[Three-dimensional finite element analysis of cement flow in abutment margin-crown platform switching]

OBJECTIVE

To analyze the cement flow in the abutment margin-crown platform switching structure by using the three-dimensional finite element analysis, in order to prove that whether the abutment margin-crown platform switching structure can reduce the inflow depth of cement in the implantation adhesive retention.

METHODS

By using ANSYS 19.0 software, two models were created, including the one with regular margin and crown (Model one, the traditional group), and the other one with abutment margin-crown platform switching structure (Model two, the platform switching group). Both abutments of the two models were wrapped by gingiva, and the depth of the abutment margins was 1.5 mm submucosal. Two-way fluid structure coupling calculations were produced in two models by using ANSYS 19.0 software. In the two models, the same amount of cement were put between the inner side of the crowns and the abutments. The process of cementing the crown to the abutment was simulated when the crown was 0.6 mm above the abutment. The crown was falling at a constant speed in the whole process spending 0.1 s. Then we observed the cement flow outside the crowns at the time of 0.025 s, 0.05 s, 0.075 s, 0.1 s, and measured the depth of cement over the margins at the time of 0.1 s.

RESULTS

At the time of 0 s, 0.025 s, 0.05 s, the cements in the two models were all above the abutment margins. At the time of 0.075 s, in Model one, the gingiva was squeezed by the cement and became deformed, and then a gap was formed between the gingiva and the abutment into which the cement started to flow. In Model two, because of the narrow neck of the crown, the cement flowed out from the gingival as it was pressed by the upward counterforce from the gingival and the abutment margin. At the time of 0.1 s, in Model one, the cement continued to flow deep inside with the gravity force and pressure, and the depth of the cement over the margin was 1 mm. In Model two, the cement continued to flow out from the gingival at the time of 0.075 s, and the depth of the cement over the margin was 0 mm.

CONCLUSION

When the abutment was wrapped by the gingiva, the inflow depth of cement in the implantation adhesive retention can be reduced in the abutment margin-crown platform switching structure.

[A historical review of dental schools founded by dentist Situ Bo in modern time]

About 8 dental schools were founded by Chinese dentists during modern times (1909-1949) in China. Only one still worked after the founding of the People's Republic of China, which was one of the three dental schools founded by dentist Situ Bo. There were no systematic researches on Situ Bo's participation in dentistry education. This paper analyzes the founder's experience in dentistry and in the two schools he founded at the beginning, focusing on the background and process of the schools' construction, management, teaching, teachers and students training, etc. The results show that the establishment of the first two dental schools have laid important foundation for the establishment and development of Shanghai Dental College by the reserve of trained professional teachers and accumulated valuable experience in running schools. The systematic review of this history will help us better understand the establishment and development of Shanghai Dental College and the efforts in dentistry education made by dentists growed up in modern China, as well as the early development process of stomatology.

[Formation of professor Mao Xiejun's thoughts on stomatological education]

Professor Mao Xiejun wrote a report about dental education of China in 1935. From 1948 to 1950, he published three articles containing the educational idea of "developing dentistry into stomatology". When he served as the director of the Faculty of Dentistry of Peking University Medical School in July 1950, he proposed to rename the Faculty of Dentistry into the Faculty of Stomatology,which were approved by the Ministry of Health and the Ministry of Education of the People's Republic of China in one month. The Chinese Medical Association established the Society of Stomatology the next year. Later, dentistry was successively changed into stomatology, and medical content was integrated into dental education, which was of great significance and far-reaching influence. During the developments of the thought of stomatological education in China, Professor Mao Xiejun evidently played a pivotal role. In this paper, the formation process of the thoughts of stomatological education related to professor Mao Xiejun's contribution is elucidated through studying the archives, personal letters, and historical documents, so as to enrich the researches on the history of stomatology in China and to facilitate better understanding and promoting the development of stomatology.

[Effects of pretreatment HIV drug resistance on the virological response of HIV-infected patients after 3-year antiretroviral therapy]

Objective: To investigate the impact of pretreatment drug resistance (PDR) on virological effect among HIV-infected patients having received antiretroviral therapy (ART) after three years. Methods: The baseline survey of PDR among HIV-infected patients was conducted in 2018, with a three-year follow up study. The clinic data and virological laboratory test variables were statistically analyzed. Results: Of the 2 433 participants, 41.6% (1 012/2 433) were aged between 18 and 34, 82.8% (2 015/2 433) were males, 46.9% (1 142/2 433) had education of high school or above, 22.4% (544/2 433) were farmers, 33.8% (823/2 433) were unmarried, 48.1% (1 169/2 433) were infected heterosexually and 41.3% (1 004/2 433) were with CRF07_BC. The prevalence of PDR was 4.5% (109/2 433). The prevalence of virological suppression failure (viral load ≥50 copies/ml) and drug resistance at three years follow up after ART was 8.1%(196/2 433) and 2.5%(60/2 433) respectively. The prevalence of virological suppression failure and drug resistance at three years follow up after ART were 18.3% (20/109) and 7.6% (176/2 324), and 4.6% (5/109) and 2.4% (55/2 324) among participants with PDR and non-PDR, respectively. The results of multivariate logistic regression model showed that illiteracy (aOR=3.26, 95%CI: 1.82-5.86), primary and junior high school education (aOR=1.54, 95%CI: 1.09-2.18), CD4⁺T lymphocyte count <200/μl (aOR=2.77, 95%CI: 1.75-4.37) and CD4⁺T lymphocyte count 200-499/μl (aOR=1.55, 95%CI: 1.10-2.18) at a three year follow up visit after ART, missed drugs in the past month (aOR=4.24, 95%CI: 2.92-6.17), and PDR (aOR=2.84, 95%CI: 1.67-4.85) were statistically significant with virological suppression failure on treatment. Conclusions: The prevalence of PDR in China at a low level currently, and the virological suppression failure rate is low after three years of ART. It is necessary to strengthen drug resistance monitoring of HIV-infected patients and pay attention to the influence of PDR on treatment effect.

[Construction and application of virtual patients in prosthodontics]

In recent years, with the rapid development of digital technology, the application of oral virtual patients in prosthodontics, orthodontics, oral and maxillofacial surgery, and other disciplines has gradually increased. Although the focus on oral virtual patients varies in different disciplines, the application of oral virtual patients in assisting the prediction of treatment effects and the formulation of treatment plans will have good prospects. The construction accuracy and presentation effects of oral virtual patients can be influenced by the source of three-dimensional (3D) image, and methods of registration. Based on the studies and clinical experiences of our team, researches of other teams, the source of 3D images, the construction methods, and the clinical applications of virtual patients in prosthodontics will be presented, so as to provide a reference for normalized application and development of oral virtual patients and to offer a future development direction of oral virtual patients.

[Factors associated with death and attrition in HIV-infected children under initial antiretroviral therapy in Guangxi Zhuang Autonomous Region, 2004 - 2019]

Objective: To investigate death and attrition in HIV-infected children under initial antiretroviral therapy (ART) and associated factors in Guangxi Zhuang autonomous region. Methods: This retrospective cohort study was conducted in HIV-infected children under initial ART in Guangxi from 2004 to 2019, data from ART information system of National comprehensive AIDS prevention and treatment information system. Cox proportional hazards models were used to assess factors associated with the death and attrition. Results: In 943 HIV-infected children, the overall mortality and attrition rates were 1.00/100 person-years and 0.77/100 person-years, respectively. The mortality and attrition rates within the first year of ART were 3.90/100 person-years and 1.67/100 person-years, respectively. The cumulative survival rate during the first, second, fifth and tenth year after ART was 96.14%, 95.80%, 93.68% and 91.54%, respectively. Multivariate Cox proportional hazards models results showed that being female (aHR=2.00, 95%CI: 1.17-3.40), CD4⁺T lymphocytes (CD4) counts before ART <200 cells/μl (aHR=2.79, 95%CI: 1.54-5.06), weight-for-age Z score before ART <-2 (aHR=2.38, 95%CI: 1.32-4.26), hemoglobin before ART <80 g/L (aHR=2.47, 95%CI: 1.24-4.92), initial ART with LPV/r (aHR=5.05, 95%CI: 1.15-22.12) were significantly associated with death; being female (aHR=2.23, 95%CI: 1.22-4.07) and initial ART with LPV/r (aHR=2.02, 95%CI: 1.07-3.79) were significantly associated with attrition. Conclusions: The effect of ART in HIV-infected children in Guangxi was better, but the mortality and attrition rates were high within the first year of treatment. It is necessary to strengthen the training in medical staff and health education in HIV-infected children and their parents in order to improve the treatment effect.

Research progress of anti-glioma chemotherapeutic drugs (Review)

Glioma is the most common primary intracranial malignancy in the central nervous system. At present, the most important treatment option is surgical resection of the tumor combined with radiotherapy and chemotherapy. The principle of operation is to remove the tumor to the maximal extent on the basis of preserving brain function. However, prominent invasive and infiltrative proliferation of glioma tumor cells into the surrounding normal tissues frequently reduces the efficacy of treatment. This in turn worsens the prognosis, because the tumor cannot be completely removed, which can readily relapse. Chemotherapeutic agents when applied individually have demonstrated limited efficacy for the treatment of glioma. However, multiple different chemotherapeutic agents can be used in combination with other treatment modalities to improve the efficacy while circumventing systemic toxicity and drug resistance. Therefore, it is pivotal to unravel the inhibitory mechanism mediated by the different chemotherapeutic drugs on glioma cells in preclinical studies. The aim of the present review is to provide a summary for understanding the effects of different chemotherapeutic drugs in glioma, in addition to providing a reference for the preclinical research into novel chemotherapeutic agents for future clinical application.

[Clinical outcome of single posterior implant-supported monolithic zirconia crowns fabricated using full digital workflow and conventional workflow: a 3-year follow-up]

Objective: To compare the clinical performance of posterior single implant-supported monolithic zirconia crowns fabricated by full digital workflow and that of those fabricated by conventional workflow. Methods: This is prospective clinical research. Thirty-five patients who participated in a previous study during August 2017 to October 2018 at Department of Prosthodontics, Peking University School and Hospital of Stomatology were included in this 3-year follow-up study. The 35 patients, 17 females and 18 males, aged (49.0±15.4) years (24-86 years old), was allocated into two groups. In the full digital workflow group, intraoral scanning was taken immediately after implant placement, and a full zirconia implant crown was fabricated using model-free computer aided design/computer aided manufacturing (CAD/CAM) procedure (n=14). In the conventional group, a conventional impression was taken 3 months after implant placement and the stone model was produced. A full zirconia implant crown was fabricated using conventional model-based procedure (n=21). Three years following crown delivery, all the prostheses were evaluated in the aspect of color, surface roughness, contour and marginal integrity using modified US Public Health Service criteria (MUSPHS criteria). The soft and hard tissue around implant was evaluated using modified plaque index, probing depth (PD), number of implants with bleeding on probing, marginal bone loss (MBL). The biological and mechanical complication were also recorded. Statistical analysis was performed using independent samples t test, Mann-Whitney U test and Fisher's exact test. Results: The total survival rate of prosthesis and implant was 100% (35/35). No significant difference in MUSPHS criteria ratings on color, surface roughness, contour and marginal integrity of these crowns were found between the full digital workflow group and the conventional group (P>0.05). Sixteen out of the 35 crowns had a contour score of B due to loss of interproximal contact. Ten out of the 35 crowns had the screw hole sealing resin sinking or falling off, four in the full digital workflow group and six in the conventional group. There was no significant difference in the rate of prostheses mechanical complications between the two groups (P=1.000). For all the implants, there was no significant difference in MBL, PD, the modified plaque index, and number of implants with bleeding on probing between the two groups (U=119.50,133.00,142.50, t=-0.53, P>0.05). Conclusions: The clinical performance of implant-supported posterior single monolithic zirconia crowns fabricated by full digital workflow was stable. There was no significant difference in the clinical performance of the single implant crowns between the full digital workflow group and the conventional group.

Advances in metformin‑based metabolic therapy for non‑small cell lung cancer (Review)

Therapeutic approaches that target the metabolism of tumor cells have been a popular research topic in recent years. Previous studies have demonstrated that glycolysis inhibitors reduce the proliferation of non‑small cell lung cancer (NSCLC) cells by interfering with the aerobic glycolytic pathway. However, the mitochondrial oxidative phosphorylation (OXPHOS) pathway in tumor cells has also been implicated in lung cancer metabolism. Metformin, a known inhibitor of mitochondrial OXPHOS, has been indicated to reduce NSCLC morbidity and mortality in clinical studies. The present article reviewed the therapeutic effects of metformin against NSCLC, both as a single agent and combined with other anticancer treatments, in order to provide a theoretical basis for its clinical use in adjuvant therapy for NSCLC.

[Application and research progress of digital virtual simulated design in dental esthetic rehabilitation]

In dental esthetic rehabilitation, patients pay great attention to the rehabilitative esthetic effect before teeth preparation, and this is also an important content of doctor-patient communication. Along with the development and combined application of intraoral scan, three-dimensional (3D) face scan, digital design, numerical control machining and 3D printing technology, digital technology is gradually applied to the virtual simulated design before irreversible operation in dental esthetic rehabilitation. Digital technology can be used in dentistry to simulate the esthetic outcome in advance, to assist communication among the dentists, patients and dental technicians, and to realize satisfactory outcome in the final restorations precisely, which, as a result, increases the clinical satisfaction. This review focuses on the application of digital virtual simulated design technology in dental esthetic rehabilitation, analyzes the current research development, deficiency and future prospects, so as to provide guidance for clinical diagnosis and treatment.

Human Motion Tracking Using 3D Image Features with a Long Short-Term Memory Mechanism Model-An Example of Forward Reaching

Human motion tracking is widely applied to rehabilitation tasks, and inertial measurement unit (IMU) sensors are a well-known approach for recording motion behavior. IMU sensors can provide accurate information regarding three-dimensional (3D) human motion. However, IMU sensors must be attached to the body, which can be inconvenient or uncomfortable for users. To alleviate this issue, a visual-based tracking system from two-dimensional (2D) RGB images has been studied extensively in recent years and proven to have a suitable performance for human motion tracking. However, the 2D image system has its limitations. Specifically, human motion consists of spatial changes, and the 3D motion features predicted from the 2D images have limitations. In this study, we propose a deep learning (DL) human motion tracking technology using 3D image features with a deep bidirectional long short-term memory (DBLSTM) mechanism model. The experimental results show that, compared with the traditional 2D image system, the proposed system provides improved human motion tracking ability with RMSE in acceleration less than 0.5 (m/s²) X, Y, and Z directions. These findings suggest that the proposed model is a viable approach for future human motion tracking applications.

[Clinical application of a prefabricated interocclusal recording cap for making interocclusal records of implant-supported fixed prostheses]

Objective: To use a self-developed, prefabricated cap for making interocclusal records in implant-supported fixed prosthetic treatment, and to evaluate its effect of clinical application and accuracy of transferring intra-oral intercuspal position. Methods: Series of prefabricated caps for occlusal recording of implant-supported fixed prostheses were designed based on the healing abutments, and fabricated with three-dimensional (3D) printing. According to the inclusion and exclusion criteria, 12 partially edentulous patients who visited the Department of Prosthodontics, Peking University School and Hospital of Stomatology between November 2020 and September 2021, had lost no fewer than 2 contiguous teeth in distal extension (Kennedy Class Ⅰ or Ⅱ), and had received implant placement 3 months ago were enrolled. Self-control study design was used. Two occlusal records of each included case were obtained by the following 2 methods: for the test group, appropriate prefabricated caps were used; and for the control group, polyvinyl siloxane occlusal record was directly set on the healing abutments. The working casts were mounted on the mechanical articulator using the 2 groups of occlusal records successively. Accuracy of occlusal relationship of the mounted casts was evaluated. Diagnostics test was performed to obtain the sensitivity and positive predictive value, which were determined in photographs by comparing the intra-oral occlusal contact points with those in the mounted casts, point-by-point. Virtual casts were taken by intraoral and extraoral scans in intercuspal position and imported to Geomagic Studio 2014. Then the root mean square values of occlusal clearance space between the upper and lower occlusal surfaces of remaining posterior teeth, and the deviations of the interocclusal position of the occlusal surfaces of the remaining teeth in the mandibular arches when superimposing the maxillary arches of the intraoral and extraoral scans were calculated. As a self-control design, paired t test was used. Results: Twelve participants were enrolled, including 3 men and 9 women aged (52.6±12.1) years, and 36 missing teeth. The prefabricated caps could fit on the healing abutments with good retention and stability. The sensitivity of the test group (0.73±0.14) was significantly better than that of control group (0.63±0.12,P<0.01), with no significant difference in positive predictive value between the 2 groups (P>0.05). The deviations of the interocclusal position of the occlusal surfaces of the remaining teeth were (357.0±140.2) μm for the test group, and (399.4±206.3) μm for the control group, with no significant difference between them (P>0.05). Conclusions: Interocclusal position record based on prefabricated cap in this study for implant-supported fixed prosthetic treatment can improve the consistency between the intra-oral occlusion and the occlusion in dental casts. This technique has good accuracy, clinical convenience and usability.

[Quantitative study of intraoral scanners' accuracy]

Objective: To establish a standard method to evaluate the scanning accuracy of intraoral scanner (IOS) and to investigate six IOS's scanning accuracy and the relationship between different scan span. Methods: Five simplified six abutments full arch model were fabricated by high accuracy (5 μm) milling machine with 7075 aluminum alloy. The machining accuracy, which was verified by a coordinate measuring machine with higher accuracy (0.7 μm), was considered as the reference accuracy. The model with the highest machining accuracy was considered as the test model in IOS's scanning accuracy test, and computer-aided design (CAD) data of the model was used as the reference data. Six IOS scanned the test model 10 times with the same scanning path, obtained 60 test data. CAD data and test data were input into Geomagic Studio 2014. The preparation part above the margin of the abutments of the data was isolated and divided into 4 segments of interest: single crown, three-unit bridge, five-unit bridge, and full arch. The test data were then best-fit aligned to CAD data or each other followed by deviation analysis. Scanning trueness and precision were then calculated. Results: The mid-value of scanning trueness and precision of six IOS in single crown, three-unit bridge, five-unit bridge and full arch were 13.3-29.6 μm and 7.6-20.7 μm, 15.4-30.9 μm and 8.7-26.5 μm, 17.0-66.1 μm and 11.3-44.2 μm, 24.0-107.9 μm and 24.6-150.1 μm respectively. Conclusions: Long-span scanning can affect the accuracy of IOS to a varying extent.

[Advances in computer aided design and computer aided manufacturing of removable partial denture]

Computer aided design, numerically controlled milling, additive manufacturing and other digital technologies have been widely used in clinical practice of prosthodontics. The application of these technologies not only changed the design and manufacturing workflow of removable partial denture (RPD), but also improved the production efficiency of dentures, and changed the design and manufacturing concept of dentures. A large number of researches on computer aided design and computer aided manufacturing (CAD/CAM) of RPD have emerged in recent years, including researches on the properties of selective laser melting metal powder and other new dental materials, the innovative design of retainers, connectors, artificial teeth and other denture components, high precision manufacturing of the RPD framework, denture base and artificial teeth, quantitative laboratory evaluations of the accuracy, adaption and mechanical properties of RPD with new structures and made of new materials, clinical evaluations of RPD and others. This paper introduces these recent developments in CAD/CAM of RPD.

[Present status and outlook of prosthodontic treatments based on three-dimensional printing technologies]

Three-dimensional (3D) printing prostheses or prosthodontic devices have been preliminarily used in the clinics of prosthodontics. These prostheses or devices include diagnostic prostheses, crowns and fixed bridges, removable denture frameworks, implant surgical template, and custom-made implants, etc. There are three major types of technologies for 3D printing according to the forming principles, namely, light curing, sintering or melting, and melting-condensation. The materials used in 3D printing prostheses or devices include polymers, metals, and ceramics, etc. The advantages of 3D printing prostheses include material-saving, customized manufacturing for restorations, and batch production. However, the precision and strength of prostheses or devices, long-term clinical effects, and grade of maturity in customized manufacturing need further investigation and improving. This article focused on the present application, and the future development of 3D printing technologies in prosthodontic treatments. It will provide beneficial references for the future studies, development, and clinical application of 3D printing technologies and restorations in prosthodontic fields.

[Investigation of posterior teeth displacement under normal bite force by an intraoral scanner]

Objective: To quantitatively evaluate the change of the long axis angle and the relative displacement of the crown feature points of the posterior teeth under normal bite force utilizing an intraoral scanner, and to provide clinical reference. Methods: From May to December 2019, fifteen graduate volunteers (5 males and 10 females, aged from 22 to 30, with an average age of 25.7 years) from Peking University School and Hospital of Stomatology were recruited to participate in the study. The surface data (U1, L1) of the maxillary and mandibular posterior teeth were scanned by an intraoral scanner i500, and saved as original data. The volunteers were guided to bite in the intercuspal position with normal bite force. The buccal bite data of the posterior teeth were scanned as the basis for registration. The digital casts were imported into Geomagic studio 2013 software and the boundary lines along the gingival margin and mesial and distal contact area of posterior teeth of data (U1, L1) were determined. Long axis of the crown, crown centroid and mesial functional cusp vertex were establishd. The data (U1, L1) were segmented into single tooth. Single tooth was aligned to buccal bite data separately using best-fit alignment command based on the buccal common area of the crown and new casts data (U2, L2) were obtained as the data under bite force. The long axis angle and centroid distance between adjacent teeth (second premolar and first molar, second molar and first molar) were measured and the deviation between data obtained at mouth-open state and that at biting state was calculated. Negative value meant centroid distance became shorter under bite force. The first molar was set as the common area and registrate the U1, L1 to U2, L2. The angle of long axes, and displacement of centroid and of functional cusp vertex between second premolar of two casts were calculated, as well as between second molar of two casts. Wilcoxon signed rank test was used to analyze the differences of teeth displacement between second premolar and second molar, and between maxillary and mandibular jaws with SPSS 26.0 statistical software. Results: The result of second premolar and second molar in the same jaw had no statistical difference (P>0.05). The centroid distance deviation of mandibular second premolar-first molar [-0.022(0.046) mm] was larger than that of maxilla [-0.006 (0.040) mm] (P<0.05). The long axis angle of second premolar itself [0.913°(0.647°)] and centroid distance of second molar itself [0.102 (0.106) mm] on the mandibular jaw were different from that on the maxillary jaw, which were 0.590°(0.550°) and 0.074(0.060) mm respectively (P<0.05). Conclusions: Under bite force, displacement of the second premolar and second molar was present, including the displacement of centroids and deflection of long axes. The mandibular posterior teeth have larger displacement than the maxillary teeth.

[Applications of stem cell-derived extracellular vesicles in bone regenerative therapy]

Stem cell-derived exosomes and microvesicles are nanoscale extracellular vesicles which have merged as mediators of intercellular communication through delivering bioactive substances. They have showed promising potential in regenerative therapy due to their capacity in promoting tissue regeneration. It has been reported that stem cell-derived extracellular vesicles could enhance bone regeneration. The underlying mechanisms included inhibiting osteocyte apoptosis induced by ischemia and hypoxia, enhancing the proliferation, migration, and osteogenic differentiation of stem cells, and promoting angiogenesis. Further investigations indicated that microRNA seemed to play an important role in exosome-mediated regeneration. In this review, we summarized the biogenesis, components and functions of stem cell-derived extracellular vesicles as well as the current progress of their mechanisms and applications in bone regeneration.

Influenza a virus and Streptococcus pneumonia coinfection potentially promotes bacterial colonization and enhances B lymphocyte depression and reduction

Influenza has frequently been epidemic in recent years. However, the mechanisms of severe pneumonia with postinfluenza Streptococcus pneumoniae (SP) secondary infection have not been fully understood. In this study, we explored the mechanisms of pneumonia in postinfluenza A virus (IAV) infection via a mouse model. Mice were intranasally inoculated with SP three days after IAV inoculation. We then collected samples at three time points to dynamically observe the pathological progression. In IAV infection alone, lymphocyte infiltration and widened alveolar intervals were observed. In the blood, levels of the CD19+, CD19+CD21+ and CD19+CD79β+B lymphocyte subpopulations were reduced, and IFN-γ and IL-10 were elevated. Slight atrophy was seen in the spleen, which was due to splenic B lymphocyteinitiated apoptosis through the mitochondrial pathway. When SP infection occurred after IAV infection, the pulmonary inflammation was significantly aggravated; a fair number of lymphocytes and neutrophils infiltrated simultaneously with exfoliated bronchial epithelial cells, vascular endothelial cells, widened alveolar septum and hemorrhaging. Increasing edema fluid and bacteria accumulated in the alveolar cavity. Decreased CD19+, CD19+CD21+ and CD19+CD79β+B lymphocyte subpopulations and increased interferon gamma (IFN-γ) or interleukin 10 (IL-10) were more prominent compared to those with viral infection alone. Spleen atrophy resulting from coinfection was more obvious because of massive splenic B lymphocyte apoptosis through the mitochondrial pathway compared to viral infection alone. This study shows that although inflammation caused by SP infection alone was temporary, preceding IAV infection provided favorable conditions for SP colonization and multiplication by destroying lung structure and suppressing humoral immunity. Synergistic IAV-SP coinfection is likely to facilitate more SP colonization and promote B lymphocyte-suppression and reduction. Eventually, the pneumonia worsened.

[Protective effects of oligomeric proanthocyanidins in mice exposed to paraquat]

Objective: To investigate the protective effect of oligomeric proanthocyanidins (OPCs) in paraquat-exposed mice. Methods: An acute lung injury model was established by a single intraperitoneal injection of paraquat (PQ) in BALB/c mice. The mice were randomized into control group, paraquat-exposed group (PQ group) , oligomeric proanthocyanidins group (OPCs group) , and paraquat and oligomeric proanthocyanidins-exposed group (PQ+OPCs group) , with 10 mice in each group. Only normal saline was intraperitoneally injected into the mice in the control group. The mice in the PQ group were divided into 8 subgroups according to the dose of poison administered, i.e., 0, 25, 50, 75, 100, 150, 200, and 300 mg/kg; the mice in each subgroup were given a single intraperitoneal injection of PQ and were observed and recorded for death at 3, 6, 12, 24, 36, 48, 60, 84, and 96 hours after PQ injection. Origin 8.0 was used to calculate the median lethal dose (LD(50)) of the mice at 24, 36, 48, and 60 hours after PQ injection, and the PQ dose (100 mg/kg, ip) was chosen based on the accumulated mortality rate. An OPCs-treated experimental model was established by an intraperitoneal injection of OPCs followed by a single PQ injection (100 mg/kg, ip) 1 hour later to observe the effects of OPCs on the apparent poisoning effect and fatality rate in PQ-induced mice. Immunohistochemistry was used to determine the effect of OPCs on PQ-induced lung tissue lesions. The peripheral blood samples of the mice were collected to determine the effects of OPCs on PQ-induced inflammatory factors such as tumor necrosis factor-α (TNF-α) , interleukine-1β (IL-1β) , and transforming growth factor-β1 (TGF-β1) using enzyme-linked immunosorbent assay. Results: The mortality rate was significantly correlated with the dose and exposure time in PQ-exposed mice; the mortality rate gradually increased with increasing dose and exposure time of the poison (P<0.05) . The LD(50) values for the mice were 216.67, 124.11, and 71.24 mg/kg at 24, 48, and 72 hours after PQ exposure, respectively. PQ could induce animal death at 12 hours after injection, and the mortality rate of the animals was 40% (4/10) at 48 hours after PQ exposure. The PQ-induced mortality rate of the mice in the PQ+OPCs group was reduced, and the mortality rate of the animals was 10% (1/10) at 48 hours after PQ exposure. Compared with treatment in the control group, OPCs exposure alone had no significant effect on the expression of TNF-α and TGF-β1 in the peripheral blood (P>0.05) , but it significantly inhibited the expression of IL-1β (P<0.05) . After 48 hours, the expression of TNF-α, TGF-β1, and IL-1β in peripheral blood significantly increased by 39%, 45%, and 38%, respectively, in the PQ group (P<0.05) , but they significantly decreased by 31%, 13%, and 22%, respectively, in the OPCs+PQ group as compared with the PQ group (P<0.05) . Conclusion: OPCs pretreatment can significantly alleviate PQ-induced poisoning effect.

[Preliminary clinical application of complete digital workflow of design and manufacturing occlusal splint for sleep bruxism]

OBJECTIVE

To establish a complete workflow of digital design and manufacturing occlusal splint for sleep bruxism, which can be preliminarily applied in clinical use, thus observe the clinical efficacy.

METHODS

Twenty-four patients with sleep bruxism were recruited in the study and randomly divided into two groups by using random number tables. Digital-occlusal-splint (experimental group) treatment plan and traditional-occlusal-splint (control-group) treatment plan were carried out for each group, respectively. For experimental group, digital models of patients' both dental arches and the occlusion relationship after elevation were captured using an intraoral scanner. The occlusal splint was carried out by computer aided design/computer aided manufacturing (CAD/CAM), including splint designing and milling. For control group, the traditional soft occlusal splint was fabricated by vacuum laminator. The two kinds of occlusal splints were tried in the patients from each group, and the occlusal contacts were tested respectively by T-scan analysis system, which recorded the changes of occlusal indicators in the two groups. The retention, appearance and occlusal comfort degree were evaluated by the two groups of patients. Mann-Whitney test was performed with IBM SPSS 20.0 software, and bilateral test was performed. P<0.05 was considered to be statistically significant.

RESULTS

The complete workflow of digital design and manufacturing occlusal splint was successfully established. During the clinical use, there was no statistical difference in the retention evaluation of two kinds of occlusal splints between the two groups of patients (Z=-0.538, P=0.590). The appearance score (Z=2.038, P=0.042) and the occlusal comfort score (Z=-2.579, P=0.010) of the experimental group were higher than those of the control group, with statistically significant differences. The T-scan analysis results showed that only the second molar on both sides of the traditional occlusal splint had occlusal contact in intercupsal position, while the digital occlusal splint had stable and bilaterally balanced contact between the maxillary and mandibular teeth. Furthermore, the occlusal force was uniformly distributed in the experimental group.

CONCLUSION

The complete workflow of digital occlusal splint improves the occlusal design, greatly simplifies and optimizes the traditional process of making occlusal splint. This new method is resource-saving and environmental-friendly, and it is able to serve patients more conveniently and efficiently.

[Establishment of a 3D printing system for bone tissue engineering scaffold fabrication and the evaluation of its controllability over macro and micro structure precision]

OBJECTIVE

To establish a 3D printing system for bone tissue engineering scaffold fabrication based on the principle of fused deposition modeling, and to evaluate the controllability over macro and micro structure precision of polylactide (PLA) and polycaprolactone (PCL) scaffolds.

METHODS

The system was composed of the elements mixture-I bioprinter and its supporting slicing software which generated printing control code in the G code file format. With a diameter of 0.3 mm, the nozzle of the bioprinter was controlled by a triaxial stepper motor and extruded melting material. In this study, a 10 mm×10 mm×2 mm cuboid CAD model was designed in the image ware software and saved as STL file. The file was imported into the slicing software and the internal structure was designed in a pattern of cuboid pore uniform distribution, with a layer thickness of 0.2 mm. Then the data were exported as Gcode file and ready for printing. Both polylactic acid (PLA) and polycaprolactone (PCL) filaments were used to print the cuboid parts and each material was printed 10 times repeatedly. After natural cooling, the PLA and PCL scaffolds were removed from the platform and the macro dimensions of each one were measured using a vernier caliper. Three scaffolds of each material were randomly selected and scanned by a 3D measurement laser microscope. Measurements of thediameter of struts and the size of pores both in the interlayer overlapping area and non-interlayer overlapping area were taken.

RESULTS

The pores in the printed PLA and PCL scaffolds were regular and interconnected. The printed PLA scaffolds were 9.950 (0.020) mm long, 9.950 (0.003) mm wide and 1.970 (0.023) mm high, while the PCL scaffolds were 9.845 (0.025) mm long, 9.845 (0.045) mm wide and 1.950 (0.043) mm high. The struts of both the PLA and PCL parts became wider inthe interlayer overlapping area, and the former was more obvious. The difference between the designed size and the printed size was greatest in the pore size of the PLA scaffolds in interlayer overlapping area [(274.09 ± 8.35) μm)], which was 26.91 μm. However, it satisfied the requirements for research application.

CONCLUSION

The self-established 3D printing system for bone tissue engineering scaffold can be used to print PLA and PCL porous scaffolds. The controllability of this system over macro and micro structure can meet the precision requirements for research application.

[Systemic lupus erythematosus with acquired hemophilia A: a case report]

Acquired hemophilia A (AHA) is anunusual disease resulting from autoantibodies (inhibitors) against coagulation factor VIII (FVIII) and clinically manifests as bleeding, which sometimes can cause potentially limb-threatening or life-threatening situations. AHA is associated with cancers, auto-immune disorders, infections, dermatologic conditions and certain medications, among which it is commonly secondary to multiple rheumatologic conditions, such as rheumatoid arthritis, systemic lupus erythematosus (SLE), pollymyositis, autoimmune hemolytic anemia and undifferentiated connective tissue disease. In autoimmune diseases, it may be the result of autoantibody producing against FVIII, and some cases of AHA may act as the first manifestation of SLE. AHA should be suspected in patients who have spontaneously hemorrhagic events with an isolated prolonged activated partial thromboplastin time (APTT), reduced FVIII activity and a negative lupus anticoagulant (LA). When FVIII inhibitor is found, it can be diagnosed. The management of AHA focuses on the following goals: (1) controlling and preventing bleeding, (2) eradication of the inhibitor, (3) treatment of the underlying disease. Here, a case of AHA in a patient with lupus is reported. A 53-year-old man with a 4-year history of SLE developed arthralgia and ecchymotic skin lesions after arthrocentesis of knee joint. Ultrasound confirmed the presence of an intramuscular hematoma. Coagulation tests revealed that FVIII activity reduced to 1% and a prolonged APTT (92.2 s), FVIII inhibitors were found to be as high as 60.0 Bethesda Units. Initial treatments with methylprednisolone 200 mg/d were started but new hemorrhagic manifestation occurred and hisbiological indexes were not good. Then the patient was treated with intravenous pulse corticosteroids (methylprednisolone 500 mg/d), intravenous cyclophosphamide, and also plasma and prothrombin complex infusion. Subsequently, FVIII activity returned within normal ranges, FVIII inhibitors decreased and clinical improvement was significantly obtained. The patient's condition kept stable till now.Hemorrhagic events due to production of antibodies directed against coagulation factors were rarely observed in SLE and attentions should be paid to the association between SLE and AHA.Bypass treatment was considered as the immediate antihemorrhagic treatment. Corticosteroid combined with immunosuppressor was recommended as the main therapy to eradicate the inhibitors. However we still lack the therapeutic guidelines and standardized treatment in patients of AHA with SLE at present.

[Association between thyroid nodule diameter measured by ultrasound and thyroid papillocarcinoma]

Objective: To investigate the association between thyroid nodule diameter measured by ultrasound and thyroid papillocarcinoma. Methods: A total of 389 cases undergoing thyroidectomy because of thyroid nodule between January 2016 and June 2017 in Beijing Anzhen Hospital were retrospectively reviewed. Of these patients, 170 cases had thyroid papillocarcinoma, and 219 cases had benign nodule. The nodules were divided into five groups according to their diameters: ≤1.0 cm, 1.1-2.0 cm, 2.1-3.0 cm, 3.1-4.0 cm, >4.0 cm. The prevalence of papillocarcinoma and lymphatic metastasis in each group were compared. Results: There were significant differences in age [(45.4±12.8) years vs (51.7±13.4) years, P<0.001], thyroid stimulating hormone (TSH) [1.75(1.28, 2.65) mU/L vs 1.48(0.99, 2.23) mU/L, P=0.003], thyroid-peroxidase antibody (TPOAb) [1.65(0.60, 8.40) kU/L vs 0.90(0.50, 2.40) kU/L, P=0.001], and C-reactive protein (CRP)[0.60(0.31, 1.37) mg/L vs 0.85(0.42, 1.66) mg/L, P=0.023] between thyroid papillocarcinoma and benign nodule. Of those(≤1.0 cm, 1.1-2.0 cm, 2.1-3.0 cm, 3.1-4.0 cm, >4.0 cm) five groups, the prevalence of papillocarcinoma was 72.5%, 52.5%, 29.7%, 16.1%, 2.4%, respectively(P<0.05). For papillocarcinoma patients, in diameter ≤1.0 cm and >1.0 cm groups, the prevalence of lymphatic metastasis was 29.9% and 45.8%, respectively (P=0.032). Binary logistic regression analysis showed that TSH (OR=1.350, 95%CI: 1.057-1.660, P=0.009), age(OR=0.960, 95%CI: 0.937-0.983, P=0.001) and nodule diameter (OR=0.359, 95%CI: 0.269-0.480, P=0.001) were independent associated factors of papillocarcinoma. Conclusion: As nodule diameter increased, the proportion of papillocarcinoma decreased, while the risk of lymphatic metastasis increased.

[Mechanism of action for oligomeric proanthocyaniclins in pava qnat-induced acute lung injury]

Objective: The present study was designed to evaluate the protective effects of oligomeric proanthocyanidins (OPC) in mice exposed to paraquat (PQ) , and to explore the molecular mechanism. Methods: Four experimental groups were designed.

CONTROL GROUP

10 BALB/c mice were intraperitoneally injected with normal saline) . PQ group: 10 BALB/c mice were intraperitoneally injected with PQ (100 mg/kg) . PQ+OPC group: 10 BALB/c mice were administered with OPC (100 mg/kg) for 1 h before PQ (100 mg/kg) expo-sure. OPC group: 10 BALB/c mice were intraperitoneally injected with OPC (100 mg/kg) . The peripheral blood samples or lung tissue samples were collected at the designed time points for measuring the levels of oxi-dative stress indicators, the related protein levels of nuclear factor-kappa B (NF-κB) pathway and nuclear fac-tor erythroid related factor-2 (Nrf2) pathway. Results: Compared with the control group, the level of reactive oxygen species (ROS) , the content of malondialdehyde (MDA) in the PQ group were significantly induced, and the activity of superoxide dismutase (SOD) in the PQ group was decreased in the peripheral blood. As com-pared with the PQ group, the level of ROS and the content of MDA in the PQ+OPC group were significantly re-duced, the activity SOD in the PQ+OPC group was increased in the peripheral blood; the level of ROS and the content of MDA were also reduced in lung tissues in the PQ+OPC group. Moreover, compared with the con-trol group, the phosphorylation of IκBα and the expression of NF-κB p65 were increased in lung tissues in the PQ group. The phosphorylation of IκBα and the expression of NF-κB p65 were decreased in lung tissues in the PQ+OPC group as compared with the PQ group. In addition, compared with the control group, the expressions of HO-1 and Nrf2 were increased in lung tissues in OPC group, and these were decreased in lung tissues in PQ groups. Furthermore, the expressions of HO-1 and Nrf2 were also increased in lung tissues in PQ+OPC as com-pared with the PQ group. Conclusion: OPC could alleviate PQ-induced systemic toxicity in mice by regulating oxidative stress via NF-κB and Nrf2 pathway.

[Renal mucinous tubular and spindle cell carcinoma combined with multiple bone metastasis: a case report and literature review]

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare sub-type of renal cell carcinoma (RCC). It has been considered to be a kind of "indolent" tumor with low-grade fashion, weak invasive capacity and relatively favorable prognosis. However, in the current case, a 3.7 cm×2.8 cm spherical mass with contrast enhancement was found in the left kidney incidentally by computed tomography (CT) in a 60-year-old male patient. A lesion in the right humerus (2.1 cm×1.6 cm×3.1 cm) was found at the same time without any symptoms or sign of pathological fracture by magnetic resonance (MR) imaging. Further positron emission tomography (PET)/CT scan which was ordered immediately after admission suggested multiple bone destruction including skull, pelvis, sternum, right humerus and femur, left scapula, multiple vertebrae and libs. Pathological examination after radical nephrectomy and palliative resection with internal fixation of the lesion in the right humerus indicated that both renal (3.0 cm×3.0 cm×2.5 cm) and bone lesions were MTSCC with the features of high-grade ovoid epithelioid cells, cord-like spindle cells and mucinous matrix under light microscope. The diagnosis of renal MTSCC concurrent with multiple bone metastasis was made. This case report suggested the necessity of general evaluation, especially bone scan for possible distant metastasis, as MTSCC might present unexpected advanced behaviors without any orthopedic symptoms. The behavior of bone metastasis might be associated with male and elderly age. MTSCC has similar enhancement features to papillary RCC on CT scan. As results, attentions are needed to differentiate MTSCC from papillary RCC as they both tend to show lesser enhancement degrees than cortex. Rather than exhibiting a dedifferentiating appearance, the pathological characteristics of bone metastasis lesion were close to those of primary renal lesion. The reason of distant metastasis to the bone remained unclear, negative expression of cytokeratin (CK) 7 might be attributed to. Though immunotherapy, chemotherapy and target therapy could all be methods for systematic therapies, procedures to remove renal lesions and prevent skeletal related events are still highly recommended.

[Three-year clinical effects of a modified semi-fixed bridge on restoring a missing posterior tooth]

OBJECTIVE

To observe the effects of a modified semi-fixed bridge to restore a missing posterior tooth for three years.

METHODS

In the study, 38 cases with a posterior tooth missed were chosen as experiment group. The inclusion criteria for these cases required that one abutment tooth be defected, and another abutment intact. The missed posterior tooth was restored with a modified semi-fixed bridge in which a metal wing retainer was applied to the intact abutment tooth and a full crown retainer was applied to the defected abutment tooth, and the non-rigid connector linked to the metal wing retainer and the pontic, while the rigid connector linked to the full crown retainer and the pontic. And 42 cases with same abutment conditions were chosen as control group. These control patients were treated with classical rigidly-fixed partial dentures. The clinical effects regarding the bridge survival, abutment conditions, and etc. were observed by examination.

RESULTS

The average observation time for experiment group was 40.3 months (from 9 to 60 months). One case failed with loose crown retainer after 7 months' usage. Another failed case was the same performance after 20 months' wearing. The restorations were rebounded after the inner face of crowns was treated, and they were used normally. No loose abutment and retainer, no decayed abutment teeth were found, and the marginal adaptations between retainers and abutment teeth were good. The average observation time of control group was 44.7 months(from 22 to 50 months). No secondary decays and loose abutment teeth were detected and the marginal adaptation of the retainers was good.

CONCLUSION

This modified semi-fixed bridge has similar survival rate and clinical effects to restore a missing posterior tooth when compared with the traditional rigidly-fixed partial dentures. But the long-term observation is required.

[Application of digital design of orthodontic-prosthodontic multidisciplinary treatment plan in esthetic rehabilitation of anterior teeth]

OBJECTIVE

To develop a digital workflow of orthodontic-prosthodontic multidisciplinary treatment plan which can be applied in complicated anterior teeth esthetic rehabilitation, in order to enhance the efficiency of communication between dentists and patients, and improve the predictability of treatment outcome.

METHODS

Twenty patients with the potential needs of orthodontic-prosthodontic multidisciplinary treatment to solve their complicated esthetic problems in anterior teeth were recruited in this study. Digital models of patients' both dental arches and soft tissues were captured using intra oral scanner. Direct prosthodontic (DP) treatment plan and orthodontic-prosthodontic (OP) treatment plan were carried out for each patient. For DP treatment plans, digital wax-up models were directly designed on original digital models using prosthodontic design system. For OP treatment plans, virtual-setups were performed using orthodontic analyze system according to orthodontic and esthetic criteria and imported to prosthodontic design system to finalize the digital wax-up models. These two treatment plans were shown to the patients and demonstrated elaborately. Each patient rated two treatment plans using visual analogue scales and the medians of scores of two treatment plans were analyzed using signed Wilcoxon test. Having taken into consideration various related factors, including time, costs of treatment, each patient chose a specific treatment plan. For the patients chose DP treatment plans, digital wax-up models were exported and printed into resin diagnostic models which would be utilized in the prosthodontic treatment process. For the patients chose OP treatment plans, virtual-setups were used to fabricate aligners or indirect bonding templates and digital wax-up models were also exported and printed into resin diagnostic models for prosthodontic treatment after orthodontic treatment completed.

RESULTS

The medians of scores of DP treatment plan and OP treatment plan were calculated and analyzed by IBM SPSS 20. The median of scores of DP treatment plan was 8.4, the minimum value was 6.9 and the maximum value was 9.3. The median of scores of OP treatment plan was 9.0, the minimum value was 7.9 and the maximum value was 9.6. The median of scores of OP was significantly higher than that of DP (Z=-3.23, P<0.01). Finally, 12 patients chose OP treatment plans and 8 patients chose DP treatment plans.

CONCLUSION

For cases with complex esthetic problems in anterior teeth, a digital workflow can demonstrate final treatment outcome and help patients make suitable treatment decisions. In our study, the orthodontic-prosthodontic multidisciplinary treatment plan is feasible which can provide predictions of treatment outcome and improve esthetic outcome with patients' satisfaction.

[Research and development of digital design and fabrication of complete denture]

Removable complete denture are still the primary prosthetic solution for edentulous patients. Functional pressure impression obtaining, jaw relation recording, personalized balance occlusion and highly precise fabrication of denture are difficult. The digital restoration technique represented by intraoral three-dimensional scanning and three-dimensional (3D) printing compensates for the shortages of the manual techniques, but there are still many limitations in the application of complete dentures. At present, a few computer aided design and computer aided manufacture (CAD/CAM) complete denture systems have been developed both domestically and abroad, and these system are mainly focused on the digital design and manufacture of denture, and are seldom used for the recording of impression and jaw relation. This review is based on the main clinical procedures of the traditional complete denture restoration, elaborating the research and application status of digital technique in each steps, in order to provide reference for clinical application.

[Influence of EDC ethanol solution on dentin shear bond strength with a self-etch adhesive system]

OBJECTIVE

To evaluate the bonding ability of one representative self-etch adhesive system by applying the micro-shear bond strength test method with different concentrations of carbodiimide [1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, EDC] ethanol solution pretreatment.

METHODS

Extracted sound human third molars were collected from patients ranging 18 to 40 years. In the study, 80 molars were first sectioned to prepare a flat middle coronal dentin surface and then were randomly divided into 5 groups (n=16) according to without/with different surface treatments [blank control; 80% (volume fraction) ethanol control; EDC ethanol solution of three concentrations (0.01 mol/L, 0.3 mol/L and 0.5 mol/L)]. Each specimen underwent a micro-shear bond strength test and failure mode observation. The data collected were subjected to statistical analysis using one-way ANOVA and post hoc Tukey's test to analyze the difference of the micro-shear bond strength, and chi-square test/Fisher's exact test for the failure mode frequency of the micro-shear bond strength test specimens at a significance level of P=0.05.

RESULTS

The micro-shear bond strength of the three concentration EDC treatments were (35.29±8.97) MPa (0.01 mol/L EDC treatment group), (40.24±9.68) MPa (0.3 mol/L EDC treatment group), (37.38±9.66) MPa (0.5 mol/L EDC treatment group) separately; and that of the 80% ethanol group was (37.49±7.76) MPa. All micro-shear bond strength value of the above four groups was statistically higher than that of the blank control group [(33.81±7.98) MPa]. The immediate micro-shear bond strength and failure mode was of no statistically significant difference among all the groups. It was noticed that the immediate micro-shear bond strength of 0.3 mol/L was higher than that of all the other groups, especially higher than that of the 80% ethanol pretreatment group despite that there was no significant difference among all the groups. And the test of failure mode indicated that the cohesive failure was more common, while the frequency of adhesive failure was rare in each experimental group.

CONCLUSION

EDC pretreatment had no adverse effect on the immediate micro-shear bond strengths of Clearfil SE Bond. Meanwhile, EDC treatment did not cause more adhesive failure in immediate micro-shear test, which had further denoted what was said above. However, it needs more research to illustrate the anti-enzymatic role of EDC in dentin bonding.

[Topographies of biomaterials regulate cell functions under epigenetic mechanisms]

Topographies of biomaterials can act as potent regulators of cell functions, including proliferation, migration, differentiation, and reprograming. The mechanisms involve not only signaling pathways, but also epigenetic regulations. A clearer picture of how topographies of biomaterials alter epigenetic states facilitates the design of highly-functionalized and individualized biomaterials, and provides novel insights into epigenetic manipulation in controlling cell fates in regenerative medicine and disease treatment.

[Quantitative evaluation of printing accuracy and tissue surface adaptation of mandibular complete denture polylactic acid pattern fabricated by fused deposition modeling technology]

Objective: To quantitatively evaluate the adaptation of polylactic acid (PLA) pattern of mandibular complete denture fabricated by fused deposition modeling (FDM) technology. Methods: A mandibular complete denture digital model was designed through a complete denture design software based on a pair of standard maxillomandibular edentulous plaster model and their occlusion bases. Ten PLA mandibular complete dentures were printed with a FDM machine. The dentures were scanned with and without the plaster model using a three-dimensional (3D) scanner. In Geomagic software, the scanning data of printed dentures were registered to its computer aided design (CAD) data, and the printing error was analyzed using the multipoint registration command. For quantitatively evaluating the adaptation of the denture, the data of plaster model and PLA denture were registered to the whole data of denture located in the plaster model using the best-fit alignment command, the 3D deviation of the plaster model and tissue surface of the denture represent the space between them. The overall area was separated into three parts: primary stress-bearing area, secondary stress-bearing area and border seal area, and the average deviations of these three parts were measured. The values were analyzed using analysis of variance. Results: Compared with the CAD data, the printing error was (0.013±0.004) mm. The overall 3D deviation between PLA denture and plaster model was (0.164±0.033) mm, in which the primary stress-bearing area was (0.165± 0.045) mm, the secondary stress-bearing area was (0.153 ± 0.027) mm, the border seal area was (0.186 ± 0.043) mm. These showed a good fit in the majority parts of the FDM denture to the plaster model. No statistically significant difference was observed between the three areas (F=1.857, P=0.175>0.05). Conclusions: Combined with the 3D scanning, CAD and FDM technology, a FDM 3D printing process of complete denture for injection moulding can be established. As a result, high efficiency and low cost can be used to print out the complete denture, to lay the basis for further clinical applications.

[Application and outlook of three-dimensional printing in prosthetic dentistry]

At present, three-dimensional (3D) printing has been applied in many aspects in the field of prosthodontics, such as dental models, wax patterns, guide plates, dental restoration and customized implants. The common forming principles include light curing, sintering and melting-condensation, the materials include pure wax, resin, metal and ceramics. However, the printing precision and the strength of multi-material integrated forming, remains to be improved. In addition, as a technology by which the internal structure of a material can be customized manufacturing, further advantage of 3D printing used in the manufacture of dental restoration lies in the customization functional bionic micro-structures, but the related research is still in its infancy. The review briefly summarizes the commonly used 3D printing crafts in prosthetic dentistry, and details clinical applications and evaluations, provides references for clinical decision and further research.

[Glucose excursion in senior patients with type 2 diabetes mellitus and coronary artery disease]

Objectives: To explore glucose excursion and incidence of hypoglycemia in senior patients with type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) with different hemoglobin A1c (HbA1c) values. Methods: Eighty-nine outpatients [58 male, 31 female, aged 69.0 (66.0, 73.0) years] diagnosed with T2DM and CAD in Beijing Anzhen Hospital between June 2013 and March 2016 were divided into group A (HbA1c<6.5%, n=25) and group B (HbA1c≥6.5%, n=64). Every patient wore continuous glucose monitoring system (CGMS) for 72 h. Glucose excursion parameters and incidence of hypoglycemia from CGMS readings were calculated. Results: Compared with group B, patients in group A experienced shorter diabetes duration [8.0 (3.5, 15.0) vs 15.0 (8.0, 20.0) years, Z=-2.222, P=0.026], lower standard deviation (SD) of blood glucose from CGMS, mean amplitude of glycemic excursions(MAGE) and mean of the daily differences(MODD) (P=0.001, 0.003, 0.001). However, incidence of hypoglycemia was significantly increased [56.0% (14/25) vs 32.8% (21/64), χ(2)=4.051, P=0.044] in group A. Compared to those who had not experienced hypoglycemia, patients with hypoglycemia had higher SD [1.8(1.4, 2.4) mmol/L vs 1.4(1.1, 1.8) mmol/L, Z=-3.198, P=0.001] and MAGE [6.0(3.2, 7.4) mmol/L vs 3.9(2.7, 4.8 )mmol/L, Z=-2.768, P=0.006] which were appropriate tools for assessing intraday glycemic variability. No statistical difference were found in MODD which was the index for estimating interday glycemic variability. Conclusions: Intensive glycemic control in senior patients with T2DM and CAD had higher incidence of hypoglycemia. Those with hypoglycemia experienced greater intraday glucose excursion.

[Immune response to one booster dose of inactivated hepatitis A vaccine in college students]

Objective: To evaluate the safety and immunogenicity of one booster dose of inactivated hepatitis A vaccine in young adults. Methods: The subjects were selected from participants in the clinical trial of immunogenicity of inactivated and attenuated live hepatitis A vaccine in young adults. Eligible subjects were those who had received one dose of inactivated or attenuated hepatitis A vaccine, could be contacted and were sero-negative before primary vaccination. All qualified subjects were immunized with one booster dose of inactivated hepatitis A vaccine. The blood samples were collected before booster dose vaccination and 28 days after the immunization. Anti-HAV antibody titer ≥20 mIU/ml was considered to be sero-protected against hepatitis A virus. Results: The GMCs in the inactivated HAV vaccine group and attenuated live vaccine group before booster dose vaccination were 70.80 mIU/ml and 50.12 mIU/ml, respectively, and the sero-protection rates were 94.7% and 65.0%, respectively. After the vaccination of the booster dose, the sero-protection rates in both groups were 100.0%, and the GMCs were 2 816.09 mIU/ml and 2 654.55 mIU/ml, respectively. Conclusion: The GMCs and sero-protection rates of anti-HAV antibody in young adults declined after three years of the primary vaccination. However, the higher GMC and sero-protection rate were observed in the inactivated vaccine group than in the attenuated live vaccine group. Significant increases of GMC levels were observed in both groups after one booster dose vaccination.

[Diagnossis and treatment of complicated anterior teeth esthetic defects by combination of whole-process digital esthetic rehabilitation with periodontic surgery]

OBJECTIVE

To explore a new method of whole-process digital esthetic prosthodontic rehabilitation combined with periodontic surgery for complicated anterior teeth esthetic defects accompanied by soft tissue morphology, to provide an alternative choice for solving this problem under the guidance of three-dimensional (3D) printing digital dental model and surgical guide, thus completing periodontic surgery and digital esthetic rehabilitation of anterior teeth.

METHODS

In this study, 12 patients with complicated esthetic problems accompanied by soft tissue morphology in their anterior teeth were included. The dentition and facial images were obtained by intra-oral scanning and three-dimensional (3D) facial scanning and then calibrated. Two esthetic designs and prosthodontic outcome predictions were created by computer aided design /computer aided manufacturing (CAD/CAM) software combined with digital photography, including consideration of white esthetics and comprehensive consideration of pink-white esthetics. The predictive design of prostheses and the facial appearances of the two designs were evaluated by the patients. If the patients chose the design of comprehensive consideration of pink-white esthetics, they would choose whether they would receive periodontic surgery before esthetic rehabilitation. The dentition design cast of those who chose periodontic surgery would be 3D printed for the guide of periodontic surgery accordingly.

RESULTS

In light of the two digital designs based on intra-oral scanning, facing scanning and digital photography, the satisfaction rate of the patients was significantly higher for the comprehensive consideration of pink-white esthetic design (P<0.05) and more patients tended to choose priodontic surgery before esthetic rehabilitation. The 3D printed digital dental model and surgical guide provided significant instructions for periodontic surgery, and achieved success transfer from digital design to clinical application. The prostheses were fabricated by CAD/CAM, thus realizing the whole-process digital esthetic rehabilitation.

CONCLUSION

The new method for esthetic rehabilitation of complicated anterior teeth esthetic defects accompanied by soft tissue morphology, including patient-involved digital esthetic analysis, design, esthetic outcome prediction, 3D printing surgical guide for periodontic surgery and digital fabrication is a practical technology. This method is useful for improvement of clinical communication efficiency between doctor-patient, doctor-technician and doctors from different departments, and is conducive to multidisciplinary treatment of this complicated anterior teeth esthetic problem.

[A novel tissue-engineered bone constructed by using human adipose-derived stem cells and biomimetic calcium phosphate scaffold coprecipitated with bone morphogenetic protein-2]

OBJECTIVE

To construct a novel biomimetic calcium phosphate (BioCaP) scaffold loaded with bone morphogenetic protein-2 (BMP-2), and to investigate its role in the osteogenesis of human adipose-derived stem cells (hASCs) in vitro and in vivo.

METHODS

The BioCaP scaffold coprecipitated with BMP-2 (BMP-2-BioCaP) was constructed in this study. Field emission scanning electron microscopy (SEM) was used to analyze the morphology of the surfaces. The release kinetics was measured to evaluate the slow-release characteristics in vitro. BMP-2-BioCaP was immersed in proliferation medium (PM) or osteogenic medium (OM), respectively. The supernatants were collected and used to culture hASCs in vitro. Cell numbers were determined using the cell-counting kit-8 (CCK-8) to assess the cell proliferation. After 7 and 14 days, alkaline phosphatase (ALP) staining and quantification were performed to test the activity of ALP. After 14 and 21 days, the calcification deposition was determined by alizarin red S (ARS) staining and quantification. The expressions of the osteoblast-related genes were tested on day 4 and day 14. In the in vivo study, 6 nude mice were used and implanted subcutaneously into the back of the nude mice for 4 groups: (1) BioCaP scaffold only, (2) BioCaP scaffold+hASCs, (3) BMP-2-BioCaP scaffold, (4) BMP-2-BioCaP scaffold+hASCs (test group). After 4 weeks of implantation, hematoxylin-eosin (HE) staining was performed to evaluate the in vivo osteogenesis of hASCs.

RESULTS

SEM observations showed that BioCaP and BMP-2-BioCaP scaffold were entirely composed of straight, plate-like and sharp-edged crystal units, and the length of the crystal units varied between 5 and 10 μm. Release kinetics analysis demonstrated that BMP-2 incorporated with BioCaP could be released at certain concentration and last for more than 21 days, and the accumulative protein release could reach 20%. CCK-8 assays showed that cell proliferation was not significantly affected by BMP-2-BioCaP. ALP activity was higher by the induction of OM+BMP-2-BioCaP than of the other groups (P<0.01). More mineralization deposition and more expressions of osteoblast-related genes such as Runt-related transcription factor 2 (RUNX2), ALP, osteopontin (OPN) and osteocalcin (OC) were determined in the OM+BMP-2-BioCaP group at different time points (P<0.01). HE staining showed that, in the test group and BMP-2-BioCaP scaffold group, the extracellular matrix (ECM) with eosinophilic staining were observed around hASCs, and newly-formed bone-like tissues could be found in ECM around the scaffold materials. Moreover, compared with the BMP-2-BioCaP scaffold group, more bone-like tissues could be observed in ECM with typical structure of bone tissue in the test groups. No obvious positive results were found in the other groups.

CONCLUSION

BMP-2-BioCaP scaffold could achieve slow-release of BMP-2 and promote the osteogenic differentiation of hASCs in vitro and in vivo. The novel tissue-engineered bone composed of hASCs and BMP-2-BioCaPis promising for the repair of bone defect.

[Evaluation of production and clinical working time of computer-aided design/computer-aided manufacturing (CAD/CAM) custom trays for complete denture]

OBJECTIVE

To compare the technician fabrication time and clinical working time of custom trays fabricated using two different methods, the three-dimensional printing custom trays and the conventional custom trays, and to prove the feasibility of the computer-aided design/computer-aided manufacturing (CAD/CAM) custom trays in clinical use from the perspective of clinical time cost.

METHODS

Twenty edentulous patients were recruited into this study, which was prospective, single blind, randomized self-control clinical trials. Two custom trays were fabricated for each participant. One of the custom trays was fabricated using functional suitable denture (FSD) system through CAD/CAM process, and the other was manually fabricated using conventional methods. Then the final impressions were taken using both the custom trays, followed by utilizing the final impression to fabricate complete dentures respectively. The technician production time of the custom trays and the clinical working time of taking the final impression was recorded.

RESULTS

The average time spent on fabricating the three-dimensional printing custom trays using FSD system and fabricating the conventional custom trays manually were (28.6±2.9) min and (31.1±5.7) min, respectively. The average time spent on making the final impression with the three-dimensional printing custom trays using FSD system and the conventional custom trays fabricated manually were (23.4±11.5) min and (25.4±13.0) min, respectively. There was significant difference in the technician fabrication time and the clinical working time between the three-dimensional printing custom trays using FSD system and the conventional custom trays fabricated manually (P<0.05).

CONCLUSION

The average time spent on fabricating three-dimensional printing custom trays using FSD system and making the final impression with the trays are less than those of the conventional custom trays fabricated manually, which reveals that the FSD three-dimensional printing custom trays is less time-consuming both in the clinical and laboratory process than the conventional custom trays. In addition, when we manufacture custom trays by three-dimensional printing method, there is no need to pour preliminary cast after taking the primary impression, therefore, it can save the impression material and model material. As to completing denture restoration, manufacturing custom trays using FSD system is worth being popularized.

[Clinical characteristics of 4 cases of scleritis associated with systemic lupus erythematosus]

Episcleritis and scleritis are relatively rare ocular diseases, which are commonly associated with rheumatic diseases including systemic lupus erythematosus (SLE). To investigate clinical and laboratory features of SLE-associated episcleritis and scleritis, we now report 4 cases of inpatients who were diagnosed with episcleritis or scleritis secondary to SLE from September 2005 to July 2016 in the Department of Rheumatology and Immunology in Peking University People's Hospital. Demographic, clinical and laboratory characteristics were summarized together with the treatment regimen and the prognosis; the literature was reviewed. There were 3 female and 1 male patients. The average age was (49.0±23.8) years and the mean duration of SLE at the onset of episcleritis or scleritis was (2.1±1.4) years. In addition to the eye involvement, the patients had mucocutaneous manifestations, serositis, lupus nephritis and interstitial pneumonia simultaneously; in the past, 1 patient experienced arthritis, 2 presented Raynaud's phenomenon, and 2 had hematologic involvement. All the patients had antinuclear antibody (ANA) of high titer. The anti double-stranded DNA (ds-DNA) antibody titers were increased in 2 patients. Three patients had positive anti-nucleosome antibody (ANuA) while the other 1 patient did not test it. The complement levels were decreased in 3 patients. The systemic lupus erythematosus disease activity index (SLEDAI) scores were more than 4 points in all the patients (ranging from 7-16), suggesting active disease. Ocular symptoms included pain, redness of the eye and tears. Ophthalmic examinations revealed 3 cases of episcleritis and 1 case of scleritis. Among the 4 patients, 2 patients experienced ocular complications including decrease in vision and uveitis. All the patients were treated with systemic corticosteroids combined with hydroxycloroquine; 3 patients were treated with immunosuppressants (cyclophosphamide in 2 patients and leflunomide in 1 patient). All of the 4 patients received topical steroid and 1 patient received periocular injection of triamcinolone acetonide; 1 patient received topical nonsteroidal anti-inflammatory drug (NSAID).No recurrence of episcleritis or scleritis was observed during the follow-ups. As a conclusion, scleritis and episcleritis, although uncommon, may occur in patients with autoimmune rheumatic diseases including SLE. The occurrence of episcleritis and scleritis may suggest active disease of SLE. Ocular complications need to be aware of in the patients. Prompt diagnosis and treatment was associated with good visual outcomes in the follow-ups.

[Progress in research and application of the edentulous custom trays]

Well designed and fabricated custom tray is the precondition to acquire qualified edentulous impression and key to successful complete denture. It has shown that primary impression without custom trays is hard to meet clinical requirements for successful restoration of complete denture. According to the fabrication techniques, edentulous custom tray can be classified into several types such as: compound trimming technique, handcrafted technique with polymerizing acrylic resin based on the study cast, and computer aided design and three dimensional printing(CAD & 3DP) technique based on the primary impression or study cast, etc. With regard to some special edentulous jaws, the custom tray and impression techniques such as open-window, frame cut, closed-mouth custom trays, and so on can be applied to acquire accurate impressions. All above technologies have their own characteristics and emphases. In clinic, appropriate custom trays should be selected according to residual ridge condition, oral status, and other clinical requirements of each edentulous patient.

Bone micro-architectural analysis of mandible and tibia in ovariectomised rats: A quantitative structural comparison between undecalcified histological sections and micro-CT

OBJECTIVES

This study aims to evaluate if micro-CT can work as a method for the 3D assessment and analysis of cancellous bone by comparing micro-CT with undecalcified histological sections in OVX rats.

METHODS

The mandible and tibia of sham, ovariectomised (OVX) and zoledronate-injected ovariectomised (OVX-ZOL) rats were assessed morphometrically. Specimens were scanned by micro-CT. Undecalcified histological sections were manufactured from the specimen scanned by micro-CT and stained with haematoxylin and eosin. Bivariate linear regressions and one-way analysis of variance were undertaken for statistics using SPSS 16.0.1 software.

RESULTS

There were highly significant correlations between undecalcified histological sections and micro-CT for all parameters (bone volume density (BV/TV), bone surface density (BS/BV), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp))in the mandible and tibia. Bone histomorphometric parameters analysed by both methods exhibited significant differences among sham, OVX, and OVX-ZOL groups. There were significant correlations between mandible and tibia in BV/TV, BS/BV, and Tb.Sp.

CONCLUSIONS

Micro-CT is a complementary tool to histological sections in basic research that could improve our understanding of bone histomorphometry. The mandible can be used as an effective site to assess bone morphometry of OVX or metabolic bone disease rat models.Cite this article: H. Liu, W. Li, Y. S. Liu, Y. S. Zhou. Bone micro-architectural analysis of mandible and tibia in ovariectomised rats: A quantitative structural comparison between undecalcified histological sections and micro-CT. Bone Joint Res 2016;5:253-262.

Effect of glycated hemoglobin on heart function of the patients with revascularization of coronary artery

BACKGROUND

Patients with diabetes after coronary artery bypass graft (CABG) or percutaneous coronary intervention (PCI) treatment for coronary artery disease (CAD) had higher mortality rates than those without diabetes. There were limited data comparing the cardiac and metabolic differences between diabetes and non-diabetes for CABG and PCI and about impact of pre-procedure GHb level on systolic heart function in patients with diabetes.

AIMS

To explore the cardio-metabolic differences and to evaluate their potential as significant risk factors.

SUBJECTS AND METHOD

124 patients with diabetes and 170 patients without diabetes were enrolled. Coronary lesions (≥ 70% stenosis in at least one major coronary artery) were documented by angiography. Patients with diabetes were divided into different groups by GHb, Coronary lesions (≥ 70% stenosis in at least one major coronary artery) were documented by angiography. CABG and PCI were performed for all the patients. Cardio-metabolic risk factors before revascularization were compared between them.

RESULTS

Diabetics with GHb ≥ 8% had lower cardiac ejection fraction (EF) values than those with GHb<8% (P<0.05) or patients without diabetes (P<0.05). And count of vascular lesions between the groups was not statistically significant. Observed EF as a dependent variable negatively correlated to GHb levels (P<0.05). The levels of glycated hemoglobin A1c (GHbA1c) rose with increased fasted blood glucose (FBG) values (P<0.001). Even with treatment for hyperglycemia and dyslipidemia, overall levels of fasting blood sugar (FBG, P<0.001), GHbA1c (P<0.001), and triglycerides (TG, P<0.05) in patients with diabetes were still higher than those without diabetes respectively.

CONCLUSION

Poorer glucose control with GHb ≥ 8% and decreased systolic heart function are significant risk factors that potentially contribute to worse prognosis for CABG or PCI treatment. Elevated levels of FBG, GHbA1c, and TG are evident for patients with diabetes compared to patients without diabetes prior to revascularization.

In situ imaging and control of layer-by-layer femtosecond laser thinning of graphene

Although existing methods (chemical vapor deposition, mechanical exfoliation, etc.) are available to produce graphene, the lack of thickness control limits further graphene applications. In this study, we demonstrate an approach to precisely thin graphene films to a specific thickness using femtosecond (fs) laser raster scanning. By using appropriate laser fluence and scanning times, graphene thinning with an atomic layer precision, namely layer-by-layer graphene removal, has been realized. The fs laser used was configured in a four-wave mixing (FWM) system which can be used to distinguish graphene layer thickness and count the number of layers using the linear relationship between the FWM signal intensity and the graphene thickness. Furthermore, FWM imaging has been successfully applied to achieve in situ, real-time monitoring of the fs laser graphene thinning process. This method can not only realize the large-scale thinning of graphene with atomic layer precision, but also provide in situ, rapid imaging capability of graphene for an accurate assessment of the number of layers.

Flame-enhanced laser-induced breakdown spectroscopy

Flame-enhanced laser-induced breakdown spectroscopy (LIBS) was investigated to improve the sensitivity of LIBS. It was realized by generating laser-induced plasmas in the blue outer envelope of a neutral oxy-acetylene flame. Fast imaging and temporally resolved spectroscopy of the plasmas were carried out. Enhanced intensity of up to 4 times and narrowed full width at half maximum (FWHM) down to 60% for emission lines were observed. Electron temperatures and densities were calculated to investigate the flame effects on plasma evolution. These calculated electron temperatures and densities showed that high-temperature and low-density plasmas were achieved before 4 µs in the flame environment, which has the potential to improve LIBS sensitivity and spectral resolution.

Contrast enhancement using silica microspheres in coherent anti-Stokes Raman spectroscopic imaging

Coherent anti-Stokes Raman scattering (CARS) microscopy is a powerful imaging technique that can provide chemical information of organic and nonorganic materials through vibrational spectroscopy. However, its contrast is not sufficient for monitoring thin film materials. In this study, silica microspheres were employed for enhancing the signal contrast in CARS imaging. One layer of optically transparent silica microspheres was self-assembled onto polymer grating samples to enhance the CARS signals. The highest contrast enhancement factor of 12.5 was achieved using 6.1-μm-diameter microspheres. Finite-difference time-domain method (FDTD) simulation was conducted to simulate the contrast enhancement with silica microspheres of different diameters.

Laser-assisted solid-state synthesis of carbon nanotube/silicon core/shell structures

A single-step solid-state synthetic approach was developed for the synthesis of silicon-coated carbon nanotube (CNT) core/shell structures. This was achieved through laser-induced melting and evaporation of CNT-deposited Si substrates using a continuous wavelength CO2 laser. The synthesis location of the CNT/Si structures was defined by the laser-irradiated spots. The thickness of the coating was controlled by tuning the laser power and synthesis time during the coating process. This laser-based synthetic technique provides a convenient approach for solid-state, controllable, gas-free, simple and cost-effective fabrication of CNT/Si core/shell structures.

Association of five SNPs at the PARK16 locus as a susceptibility locus with Parkinson's disease for forensic application

To investigate the association of five SNPs (rs823083, rs708723, rs4951261, rs823076 and rs16856110) at the PARK16 locus with Parkinson's disease (PD), and to potentiate its forensic application. The genomic DNAs of 215 PD patients and 212 matched controls from the northern Han Chinese population were amplified in two independent PCR systems and subsequently genotyped by digestion with the three endonucleases (Hinf I, Nco I and Msp I ). The genetic parameters and association studies were carried out with SPSS 13.0, Haploview version 4.2 and PLINK 1.07 softwares. We detected accurately all genotypes in the five SNPs with multiplex PCR-RFLP and mismatched multiplex PCR-RFLP techniques. The genotypes of four SNPs, except for rs823083, were in Hardy-Weinberg equilibrium. The four SNPs, rs16856110, rs4951261, rs708723 and rs823076, which were in linkage equilibrium, should not be associated with PD (P-values ranging from 0.077 to 0.544). The SNPs investigated at the PARK16 locus were not found to be involved in PD-associated blocks in the northern Han Chinese population. The allele distributions of rs708723, rs4951261, rs823076 and rs16856110 in the northern Han Chinese population can be highly polymorphic, which can be applied to genetic analysis and forensic practices.

Simulation of the Impact of Atropisomer Interconversion on Plasma Exposure of Atropisomers of an Endothelin Receptor Antagonist

BMS-207940, a potent endothelin receptor antagonist, exists as rapidly interconverting atropisomers. The plasma interconversion t(1/2) is approximately 2.5 hours at 400 microg/mL under room temperature and decreases to < 0.1 hours at 20 microg/mL, making it extremely difficult to conduct pharmacokinetic studies of individual atropisomers. The pharmacokinetics of the 50/50 racemate of BMS-207940 in humans were reasonably described by a one-compartmental model with an apparent terminal elimination t(1/2) of 15 hours. Given the above rates, simulations were conducted based on a one-compartmental model to explore the possible range of individual rates of atropisomer elimination and potential difference in plasma exposure to the two atropisomers. Simulations demonstrated that the elimination rates of the individual atropisomers are bounded between 0 and 0.046 h(-1) and between 0.046 and 0.092 h(-1), respectively. The estimation of the upper bounds for atropisomer elimination rate constants is robust and relatively insensitive to the rate of atropisomer interconversion compared to the rate of racemate elimination. Simulations of the administration of a single atropisomer or the 50/50 racemate, based on all the possible scenarios of individual atropisomer elimination, showed little difference in plasma exposure to the two atropisomers. Potential differences in plasma exposure to the two atropisomers depend, to a larger extent, on the ratio of the rate of atropisomer interconversion versus racemate elimination and, to a lesser extent, on the conformation of atropisomers administered. When atropisomer interconversion is 10-fold or more rapid than racemate elimination, the largest possible difference in plasma exposure between the two atropisomers is below 20%, regardless of the route and conformation of the atropisomer(s) administered.

Plasmonic-enhanced carbon nanotube infrared bolometers

Plasmonic nanoantennas show significant potential in photodetection applications, but the extent to which their full potential can be realized is dictated by the volume and location of the active materials within the plasmonic structure. Carbon nanotubes (CNTs) have been used as a novel material in photodetection application due to their excellent electronic and optoelectronic properties. However, difficulties in the integration of CNTs in the gaps of nanoantennas have limited the investigation of antenna-coupled CNT detectors. Here, we demonstrate a unique plasmonic approach for selectively growing CNTs in the gap of nanoantenna arrays for fabrication of plasmonic infrared bolometers operating at room temperature. Strong concentration of light at the tips of nanoantennas was utilized for localized heating and growth of CNTs. Moreover, interaction of this strong optical field with the small volume of CNTs enhanced the photoresponse of the bolometers. Consequently, a high responsivity of about 800 V W(-1) was achieved at room temperature.

Surface-enhanced Raman spectroscopy using gold-coated horizontally aligned carbon nanotubes

Gold-coated horizontally aligned carbon nanotube (Au-HA-CNT) substrates were fabricated for surface-enhanced Raman spectroscopy (SERS). The Au-HA-CNT substrates, which are granular in nature, are easy-to-prepare with large SERS-active area. Enhancement factors (EFs) of ∼10(7) were achieved using the Au-HA-CNTs as substrates for rhodamine 6G (R6G) molecules. Maximum enhancement was found when the polarization direction (E-field) of the incident laser beam was parallel to the aligned direction of the HA-CNTs. Simulations using the finite-difference time-domain (FDTD) method were carried out for the granular Au-HA-CNT samples. Enhancement mechanisms and determination of EFs were analyzed. Biological samples, including (13)C- and deuterium (D)-labeled fatty acids and Coccomyxa sp. c-169 microalgae cells, were also measured using this SERS substrate. The limits of detection (LODs) of D- and (13)C-labeled fatty acids on the SERS substrate were measured to be around 10 nM and 20 nM, respectively. Significantly enhanced Raman signals from the microalgae cells were acquired using the SERS substrate.