Preparation, Stimulus-Response Mechanisms and Applications of Micro/Nanorobots

Micro- and nanorobots are highly intelligent and efficient. They can perform various complex tasks as per the external stimuli. These robots can adapt to the required functional form, depending on the different stimuli, thus being able to meet the requirements of various application scenarios. So far, microrobots have been widely used in the fields of targeted therapy, drug delivery, tissue engineering, environmental remediation and so on. Although microbots are promising in some fields, few reviews have yet focused on them. It is therefore necessary to outline the current status of these microbots' development to provide some new insights into the further evolution of this field. This paper critically assesses the research progress of microbots with respect to their preparation methods, stimulus-response mechanisms and applications. It highlights the suitability of different preparation methods and stimulus types, while outlining the challenges experienced by microbots. Viable solutions are also proposed for the promotion of their practical use.

The influence of intra-group differences on the flocking and obstacle avoidance movement of multiagent systems

In multiagent systems, it can be hard to design individual models due to financial constraints and design challenges. Given this, most studies use the same models for each individual and fail to take into account intra-group differences. In this paper, the effects of differences within a group on flocking and obstacle avoidance movements are studied. Individual differences, group differences, and mutants are the most significant intra-group differences. The differences lie mostly in perceptual radius, inter-individual forces, and the ability to avoid obstacles and pursue goals. We designed a smooth and bounded hybrid potential function with indefinite parameters. This function satisfies the consistency control requirements of the three previously mentioned systems. It is also applicable to ordinary cluster systems without individual differences. As a result of the action of this function, the system has the advantages of rapid swarming and constant system connectivity during motion. Through theoretical analysis and computer simulation, we confirm the effectiveness of our theoretical class framework designed for a multi-agent system with internal differences.

Application of nanotechnology in reversing therapeutic resistance and controlling metastasis of colorectal cancer

Colorectal cancer (CRC) is the most common digestive malignancy across the world. Its first-line treatments applied in the routine clinical setting include surgery, chemotherapy, radiotherapy, targeted therapy, and immunotherapy. However, resistance to therapy has been identified as the major clinical challenge that fails the treatment method, leading to recurrence and distant metastasis. An increasing number of studies have been attempting to explore the underlying mechanisms of the resistance of CRC cells to different therapies, which can be summarized into two aspects: (1) The intrinsic characters and adapted alterations of CRC cells before and during treatment that regulate the drug metabolism, drug transport, drug target, and the activation of signaling pathways; and (2) the suppressive features of the tumor microenvironment (TME). To combat the issue of therapeutic resistance, effective strategies are warranted with a focus on the restoration of CRC cells’ sensitivity to specific treatments as well as reprogramming impressive TME into stimulatory conditions. To date, nanotechnology seems promising with scope for improvement of drug mobility, treatment efficacy, and reduction of systemic toxicity. The instinctive advantages offered by nanomaterials enable the diversity of loading cargoes to increase drug concentration and targeting specificity, as well as offer a platform for trying the combination of different treatments to eventually prevent tumor recurrence, metastasis, and reversion of therapy resistance. The present review intends to summarize the known mechanisms of CRC resistance to chemotherapy, radiotherapy, immunotherapy, and targeted therapy, as well as the process of metastasis. We have also emphasized the recent application of nanomaterials in combating therapeutic resistance and preventing metastasis either by combining with other treatment approaches or alone. In summary, nanomedicine is an emerging technology with potential for CRC treatment; hence, efforts should be devoted to targeting cancer cells for the restoration of therapeutic sensitivity as well as reprogramming the TME. It is believed that the combined strategy will be beneficial to achieve synergistic outcomes contributing to control and management of CRC in the future.

[Discussion on relevant issues of Technical Specifications for Occupational Health Surveillance (GBZ 188-2014)]

Technical Specifications for Occupational Health Surveillance (GBZ 188-2014) is an important basis for judging suspected occupational diseases and occupational contraindications. There are crossing over or overlap between occupational contraindications and diagnostic criteria of poisoning damage. Occupational contraindications have different meanings with the degree and range of common diseases or symptoms and the frequency of physical examination during employment conflicts with the current standard. Based on the practice of occupational health examination in a large population, the present study analyzed relevant articles and put forward some suggestions for revision, in combination with clinical medicine, occupational health standards, and diagnostic standards of occupational diseases. The modification could provide a reference for the revision of Technical Specifications for Occupational Health Surveillance and the practice of occupational health examination.

[Characteristics analysis of oral clinical trials registered in Chinese Clinical Trial Registry]

Objective: To investigate the project characteristics of oral clinical trials registered in Chinese Clinical Trial Registry (ChiCTR), and to provide reference for medical institutions to improve the quality of oral clinical trials and formulate management systems. Methods: The ChiCTR database was retrieved to collect all the oral-related clinical trials from the time of database establishment to July 25, 2021. Those clinical trials were analyzed statistically in respect of name of registered project, registration time, registration status, regional distribution of research institutions, approval status by ethics committee, sample size, source of funds, involved disease, research type and design, randomization method, and whether blind method was adopted. Results: A total of 778 oral clinical trials, which studied mainly in the oral and maxillofacial diseases, periodontal tissue diseases, oral implant diseases, oral mucosal diseases, and oral prosthetic diseases, were retrieved in the database. Beijing, Sichuan, Shanghai, Guangdong and Hubei were major regions where oral clinical trials were carried out, accounting for 69.68% (772/1 108) of the total. The top four funding sources were hospital finance [24.93% (186/746)], local government finance [22.39% (167/746)], self-financing [17.69% (132/746)], and national finance [12.47% (93/746)]. For the types of researches, 520 interventional studies and 244 observational studies were identified (accounting for 66.84% and 31.36%, respectively). The research designs were dominated by ways of randomized control (381, 48.97%), of which 240 (62.99%) trials were with missing or unspecified blinding methods. Conclusions: Oral clinical trials are increasing year by year, but they are regionally imbalanced, and still need to be further improved in registration information and research design. Administrative departments should pay more attention to strengthen the publicity and education on the registration and publication mechanism of clinical trials, and enhance researchers' cognitions in clinical trials registration and clinical trials design.

[Clinical and genetic characteristics of congenital isolated adrenocorticotropic hormone deficiency]

Objective: To investigate the clinical and genetic characteristics of congenital isolated adrenocorticotropic hormone (ACTH) deficiency. Methods: The clinical and laboratory characteristics of 5 cases with congenital isolated ACTH deficiency diagnosed in the Department of Endocrinology of the Children's Hospital, Capital Institute of Pediatrics from January 2019 to March 2021 were retrospectively analyzed. The general conditions, clinical manifestations, laboratory examinations, genetic charcteistics, treatment and follow-up (up to October 2021) were analyzed. Results: Of the 5 cases, 1 was female and 4 were males, aged from 13 months to 6 years at the time of consultation. The symptoms of hypoglycemia and convulsion were presented in infancy, and 4 cases had infantile cholestasis. Glucose level of 5 cases ranged from 0.79-2.20 mmol/L, ACTH ranged from <1.00-4.17 ng/L, and cortisol ranged from 0.2-3.8 μg/L. Whole exon sequencing revealed that 3 cases carried homozygous TBX19 variations, and 2 cases had compound heterozygous TBX19 variations, including 3 variants that had been reported before and 3 novel variants were found. After the diagnosis was confirmed, all the cases were treated with hydrocortisone. Hypoglycemia was all corrected during the follow-up, and 4 cases no longer had convulsions. Conclusion: Congenital isolated ACTH deficiency should be considered in neonates and infants with cholestasis and hypoglycemia, and the diagnosis can be confirmed by genetic testing.

Assessing the sustainable safety practices based on human behavior factors: an application to Chinese petrochemical industry

Sustainable and safe development is a key issue in petrochemical industry. However, many catastrophic accidents and irreversible environmental pollution have occurred in the petrochemical industry, most of which are caused by human behavior factor. The purpose of this paper is to evaluate and improve the sustainable safety performance of a petrochemical plant from the perspective of human behavior factors. Therefore, this study proposes an extended behavior-based safety (BBS) approach that combines the application of fuzzy analytic hierarchy process (FAHP) and fuzzy comprehensive evaluation (FCE) to assess sustainable safety performance of a petrochemical plant. The results show the importance of human behavior factors, and we should pay attention to the practical application of petrochemical industry. Finally, BBS management can reduce occupational injuries and accidents, which will enhance the sustainable safety development of the petrochemical industry.

[Histiocyte-rich rhabdomyoblastic tumor: a clinicopathological and molecular genetic analysis]

Objective: To investigate the clinicopathologic and molecular genetic characteristics, diagnosis, differential diagnosis, treatment and prognosis of histiocyte-rich rhabdomyoblastic tumor (HRRMT). Methods: The clinical data of two cases of HRRMT diagnosed in Fujian Provincial Hospital and Fujian University of Traditional Chinese Medicine Affiliated People's Hospital from 2020 to 2021 were collected. Histopathology and immunohistochemical (IHC) staining were used to assess morphological changes; the genetic changes were analyzed with next-generation sequencing. The relevant literature was reviewed. Results: Both cases showed well-defined solid nodules and soft masses. Microscopically, the tumors had a fibrous pseudocapsule with lymphocytic aggregation, and locally invaded the surrounding skeletal muscle tissue, and the tumor cells were fusiform to epithelioid with an intensive foamy histiocytic infiltrate. No necrosis or mitosis was observed. Immunophenotyping showed the tumor cells were positive for desmin, either one or both skeletal muscle markers (myogenin or MyoD1), and negative for h-caldesmon, ALK and SMA. The Ki-67 index was<5%. Using next-generation sequencing, one case was found to harbour KRAS (G12D) and MSH3 (Q470^*) mutations. Conclusions: HRRMT is a newly described skeletal muscle tumor with uncertain malignant potential. Its diagnosis and differential diagnosis depend on morphologic and IHC staining. No specific molecular genetics changes have been identified so far.

Targeting EGFR sensitizes 5-Fu-resistant colon cancer cells through modification of the lncRNA-FGD5-AS1-miR-330-3p-Hexokinase 2 axis

5-Fluorouracil (5-Fu) is a widely applied anti-cancer agent against colorectal cancer (CRC), yet a number of CRC patients have developed resistance to 5-Fu-based chemotherapy. The epidermal growth factor receptor (EGFR) is recognized as an oncogene that promotes diverse cancer progresses. In addition, long noncoding RNAs (lncRNAs) are essential regulators of cancers. Here we report that EGFR and lncRNA-FGD5-AS1 promoted 5-Fu resistance of CRC. By establishing the 5-Fu-resistant CRC cell line, we detected that EGFR, FGD5-AS1, and glucose metabolism were significantly elevated in 5-Fu-resistant CRC cells. A microRNA-microarray analysis revealed that miR-330-3p functions as a downstream effector of FGD5-AS1. FGD5-AS1 directly sponged miR-330-3p to form a competing endogenous RNA (ceRNA) network, leading to inhibition of miR-330-3p expression. Furthermore, bioinformatics analysis revealed that Hexokinase 2 (HK2) was a potential target of miR-330-3p, which was validated by luciferase assay. Rescue experiments demonstrated that FGD5-AS1 promotes glycolysis through modulating the miR-330-3p-HK2 axis, leading to 5-Fu resistance of CRC cancer cells. Finally, in vitro and in vivo xenograft experiments consistently demonstrated that inhibition of EGFR by the specific inhibitor erlotinib effectively enhanced the anti-tumor toxicity of 5-Fu by targeting the EGFR-FGD5-AS1-miR-330-3p-HK2 pathway. In summary, this study demonstrates new mechanisms of the EGFR-modulated 5-Fu resistance through modulating the noncoding RNA network, contributing to development of new approaches against chemoresistant CRC.

[Cystic echinococcosis of the abdominal wall: a case report]

Cystic echinococcosis of the abdominal wall is relatively rare. Here, a 54-year-old patient with cystic echinococcosis of the abdominal wall was reported, who was admitted to hospital due to presence of abdominal mass for one year complicated by skin ulceration of the mass for 5 days. The case was initially diagnosed as cystic echinococcosis of the abdominal wall and given sub-abdominal echinococcosis cystectomy. Post-surgical pathological examinations revealed cystic echinococcosis (type of a single locule and multiple daughter cysts). This case report aimed to provide insights into the clinical diagnosis and treatment of cystic echinococcosis of the abdominal wall.

[Cystic echinococcosis of the waist and hip: a case report]

A patient with cystic echinococcosis was presented with primary lesions in the waist and hip. The case was misdiagnosed as subcutaneous abscess at initial diagnosis, and then definitively diagnosed as echinococcosis by means of imaging examinations and anti-Echinococcus antibody test. This case was reported with aims to improve the awareness of cystic echinococcosis among clinical physicians to avoid and reduce the misdiagnosis and missing diagnosis.

[Clinical and genetic characteristics of primary hypoparathyroidism in children]

Objective: To analyze the clinical and genetic characteristics of primary hypoparathyroidism in children. Methods: The clinical data including age, symptoms, laboratory examination and cranial CT of 13 children with primary hypoparathyroidism diagnosed in the Capital Institute of Pediatrics from May 2017 to December 2019 were collected and analyzed retrospectively. These children and their parents also had gene detected by whole exome sequencing and (or) copy number variation sequencing. Results: Among the 13 patients, 7 were male and 6 female. The onset age was 3 years (1 day-12 years) old. The time from onset to confirmed diagnosis was 2 months (2 days-10 years). The clinical manifestations included convulsion (9 cases), tetany (2 cases), muscle pain (1 case), mental retardation (5 cases), deafness (1 case), and initially misdiagnosed epilepsy (5 cases). The lab examination showed average blood calcium level of (1.7±0.3) mmol/L, blood phosphorus of (2.8±0.4) mmol/L, and parathyroid hormone of 8.2 (3.9-28.7)ng/L. Head CT found 7 cases of ectopic calcification. Among the 7 cases who had genetic abnormalities according to the gene detection, 5 had heterozygous deletion of 22q11.2 region, and only one of whom was diagnosed with typical DiGeorge syndrome. As for the rest 2 cases, one had autosomal dominant hypocalcemia caused by novel heterozygous variation of CaSR gene c.2495T>G (p.F832C), and the other was hypoparathyroidism-deafness-renal dysplasia syndrome caused by GATA3 c.708dupC (p.S237Qfs*66) novel heterozygous variation. Conclusions: Primary hypoparathyroidism in children is mainly characterized by hypocalcemia and usually accompanied with diverse symptoms which may indicate genetic disorders. The detection of large fragment deletion should be considered to exclude 22q11.2 deletion syndrome.

[Effects of FoxO6 on proliferation and invasion of colorectal cancer cells]

Objective: To investigate the effects and the mechanism of FoxO6 on the proliferation and invasion of colorectal cancer cells. Methods: FoxO6 siRNA was transfected into colorectal cancer cell HCT116 and SW480. The overexpression vector pcDNA.3.1-c-Myc was constructed and co-transfected into HCT116 and SW480 cells with FoxO6 siRNA. Real-time fluorescent quantitative PCR (RT-qPCR) and western blot were used to detect the mRNA and protein expressions of FoxO6, c-Myc, and p21 in HCT116 and SW480 cells. Bromodeoxyuridine (BrdU) was used to detect cell proliferation and Transwell assay was performed to detect the invasion ability of these cells. SW480 cells transfected with FoxO6 shRNA lentivirus (LV-FoxO6) and were injected into the right armpit of BAL b/c nude mice to construct a tumor-bearing mode and the tumor volumes were measured on the days of 10, 13, 16, 19, 22, and 25 after injection. Results: The FoxO6 mRNA were 0.91±0.04, 1.72±0.07, and 2.03±0.06, and protein expression were 0.70±0.04, 1.35±0.08, and 1.56±0.07 in normal colon cell FHC, colorectal cancer cells HT116 and SW480, respectively. The protein and mRNA levels of FoxO6 in HCT116 and SW480 were significantly higher than those in FHC (both P<0.05). Knockdown of FoxO6 in HCT116 and SW480 cells decreased the mRNA and protein expressions of FoxO6 (both P<0.05), the cell proliferation ability (absorbances were 0.26±0.07 and 0.27±0.06, both P<0.05), cell invasion ability (the invaded cell numbers were 42.3±3.3 and 45.7±4.1, both P<0.05), and the mRNA and protein expressions of c-Myc, while increased the mRNA and protein expressions of p21 (both P<0.01). Overexpression of Myc in FoxO6 silenced HCT116 and SW480 cells decreased the expression of p21, while increased the cell proliferation ability (absorbances were 0.54±0.09 and 0.58±0.07, both P<0.01) and invasion ability (the invaded cell numbers were 79.2±5.9 and 80.5±6.4, both P<0.01). On the 25th day after cell inoculation in nude mice, the tumor volume of LV-FoxO6 group was (190.6±36.2) mm(3), significantly lower than (437.8.6±69.2) mm(3) of LV-NC group (P<0.05). Conclusion: FoxO6 promotes the proliferation and invasion of colorectal cancer cells through facilitating c-Myc mediated p21 expression inhibition.

Retrospective Analysis of 61 Cases of Children Died of Viral Pneumonia

Abstract

Objective To retrospectively analyze the forensic pathological postmortem examination and clinical data of children who died of viral pneumonia in identification of cause of death cases and to discuss the clinical characteristics and pathological features of viral pneumonia in children, in order to provide reference to pathological diagnosis of viral pneumonia in children caused by 2019 novel coronavirus （2019-nCoV） infection. Methods Postmortem examination data from 61 cases of children whose causes of death were identified as viral pneumonia in recent years were collected from the Center of Forensic Identification, Southern Medical University. The gender, age, clinical symptoms and pathological features were comparatively analyzed. Results Among the 61 cases of children who died of viral pneumonia, most were within 2 years old （83.61%）, and a large proportion died within 2 weeks after the onset of the disease （91.80%）. Gross changes in postmortem examination included respiratory mucosal hyperemia, pleural effusion, pulmonary swelling, variegated pulmonary pleura and serosa, as well as focal pulmonary hemorrhage and pulmonary edema. A large proportion of sick children had enlarged mesenteric lymph nodes （83.61%） and thymic dysplasia （21.31%）. Histopathological changes included edema of alveoli and interstitial substance, pneumorrhagia，shedding of alveolar epithelial cells, serous and （or） fibrous exudation in the alveoli, formation of viral inclusions, formation of transparent membranes, infiltration of inflammatory cells that mainly consisted of macrophages and lymphocytes in interstitial substance and alveoli. Viral infections often affected the heart and gastrointestinal tract. Conclusion The clinical symptoms of children with viral pneumonia are difficult to notice, and because the immune systems of children are not fully developed and they have poor immunity, they can easily become severely ill and even die. Analyzing the forensic autopsies and the histopathological characteristics could provide reference for pathological diagnosis of viral pneumonia.

[Transbronchial lung cryobiopsy in diffuse lung disease: a pathological analysis of 173 cases]

Objective: To evaluate the value of transbronchial lung cryobiopsy (TBCB) in pathological diagnosis for diffuse lung disease. Methods: The clinicopathological data of 173 patients from the first affiliated hospital of Guangzhou medical university between Jaunary 2017 and June 2019 with transbronchial lung cryobiopsy of diffuse lung disease were retrospectively analyzed and summarized with review. Among 173 cases, TBCB and conventional transbronchial lung biopsy (TBLB) were performed in 54 patients. The size of biopsy samples and diagnostic yield were compared. Results: Among 173 cases, the diagnostic yield was 85.54% (148/173) , 160 (92.49%) cases provided definite diagnosis and valuable pathological results, according to age, sex, occupation, past history, contact history, smoking history, laboratory serology and imaging findings. Among 160 cases, there were 72 cases of known etiology (45.00%), 27 cases of idiopathic interstitial pneumonia (16.88%), 7 cases of granulomatous lesions (4.38%) and 54 cases of other types (33.75%). With TBCB and TBLB in 54 patients, the specimens sizes of TBCB and TBLB were (3.3±1.3) mm(2) and (1.0±0.3) mm(2) respectively (t'=12.67 P<0.01) . The diagnostic yields of TBCB and TBLB were 81.48% (44/54) and 42.59% (23/54) respectively (χ(2)=17.33, P<0.01) . The diagnostic yields of TBCB and TBLB for interstitial lung diseases were 48.15% (26/54) and 5.56% (3/54) respectively (χ(2)=24.94, P<0.01) . However, the diagnostic yields of TBCB and TBLB for the other diffuse lung disease except interstitial lung diseases were 33.33% (18/54) and 37.04% (20/54) respectively, with no significant difference (χ(2)=0.1624, P=0.687). Conclusion: Compared with TBLB, TBCB has obvious advantages and application value in the diagnosis of diffuse pulmonary diseases, especially interstitial pulmonary diseases.

[Periostin regulated by let-7/miR-98 family mediates the apoptosis and epithelial-mesenchymal transition of colon cancer]

Objective: To observe the expressions of periostin (Postn) in colon cancer tissues and cells, and to investigate its biological effect and mechanism in colon cancer cells. Methods: Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot were used to detect the expressions of Postn, let-7a and miR-98 in 20 pairs of colon cancer tissues and adjacent normal tissues, colon cancer cell lines including SW480, HT-29, HCT-116 and human normal colon epithelial cell NCM460. Small interfering RNAs (siRNAs) of Postn, pcDNA3.1-Postn plasmids, let-7a mimic and its negative control let-7a mimic-NC, miR-98 mimic and its negative control miR-98 mimic-NC were transfected into HCT-116 cells. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) was used to detect cell viability. Flow cytometry was used to detect cell apoptosis. Luciferase reporter gene assay was used to determine the targeting relationship between miRNAs and Postn. Results: Compared with adjacent normal tissues, Postn expression was up-regulated (P<0.05) while let-7a/miR-98 expression was down-regulated (P<0.05) in colon cancer tissues. Compared with NCM460 cells, Postn expression was up-regulated (P<0.05) while let-7a/miR-98 expression was down-regulated (P<0.05) in SW480, HT-29 and HCT-116 cells. In colon cancer tissues, the expression of Postn was negatively correlated with the expressions of let-7a and miR-98 (r=-0.69, P<0.001; r=-0.80, P<0.001). Inhibition of Postn in vitro reduced the viability of HCT-116 cells [(53.73±7.63)%, P<0.05], increased the apoptotic rate [(22.88±3.40)%, P<0.05], enhanced the expression of epithelial-mesenchymal transition (EMT) marker E-cadherin (2.44±0.39, P<0.05), while down-regulated the expressions of N-cadherin and Vimentin (0.44±0.07 and 0.38±0.06, P<0.05). Overexpression of Postn in vitro enhanced the cell viability of HCT-116 cells [(134.41±8.82) %, P<0.05], decreased the expression of E-cadherin (0.55±0.09, P<0.05), increased the expressions of N-cadherin and Vimentin (2.93±0.42 and 2.24±0.34, P<0.05), but had no effect on the apoptotic rate (P>0.05). Overexpression of let-7a or miR-98 partially reversed the biological effects of Postn overexpression in colon cancer cells, which implicated that Postn was a target gene of let-7a/miR-98. Conclusions: Postn is a cancer-promoting molecule of colon cancer, and inhibition of Postn expression can increase the apoptotic rate of colon cancer cells and repress EMT. Postn expression and function is regulated by let-7a/miR-98.

[Investigation on physical activity and occupational stress among street office staffs of a city in China]

Objective: To investigate the relationship between physical activity (PA) and occupational stress(OS) among street office staffs of a city in china. Methods: A total of 504 street office staffs were collected by using stratified cluster sampling method from April to June in 2016, the international physical activity questionnaire(IPAQ) and job content questionnaire(JCQ) were used to survey the PA and OS. Results: In all subjects, the average score of job demand was(3.57±0.83), job decision was(2.71±0.63), social support was (2.79±0.79), demand-control ratio was (1.35±0.47) and 75.60% felt OS in self-evaluation. There were significant differences in OS between subjects with different gender, ages, job rank and job hours (P<0.01), also, there were significant differences in OS between different levels of occupational and leisure related PA (P<0.01). After controlling the potentially confounding effects, compared with low PA group, the OR values of medium-level and high-level groups of occupation-related PA were 1.38(95%CI=1.21~1.94) and 2.21(95%CI=2.06~2.67) respectively, however, the OR values of the medium-level and high-level groups of leisure-related PA were 0.89(95%CI=0.73~1.12) and 0.67(95%CI=0.38~0.96) respectively. Conclusion: Street office staffs have high level of OS, and leisure-related PA may be a protective factor for occupational stress.

[The efficacy and safety of transbronchial lung cryobiopsy in interstitial lung disease: a prospective study]

Objective: To evaluate the efficacy and safety of transbronchial lung cryobiopsy (TBCB) and conventional transbronchial lung biopsy (TBLB) in the diagnosis of interstitial lung diseases(ILD). Methods: A prospective, self-control study was conducted during January 2017 and April 2017 in First Affiliated Hospital of Guangzhou Medical University. A total of 25 patients [male 16, female 9; mean age (51±13) years, range 24 to 70 years] with inconclusive diagnosis of interstitial lung diseases were sequentially enrolled. In the study, TBCB (TBCB group) and TBLB (TBLB group) were performed successively under general anesthesia in all patients. The size of biopsy specimens, the duration of procedures, complications and pathological results were recorded. Gaussian distribution data were compared between 2 groups by using Student's t test, while abnormal distribution data were compared by using Wilcoxon rank sum test. The incidences of bleeding and pathologic diagnostic yield between the 2 groups were compared by using Pearson chi-square test. A P-value< 0.05 was assumed to be statistically significant. Results: The specimen sizes of TBCB group and TBLB group were (12.3+ 4.9) and (3.1+ 1.9) mm(2) respectively (t=-18.268, P=0.000). The duration of procedures was (7.8±3.2) and (5.4±2.1)min respectively (Z=-3.001, P=0.003). In TBCB group, the diagnostic yield was 72% (18/25), with valuable pathological results in 2 cases (8%), but in 5 cases (20%) it failed to provide valuable pathological results. In TBLB group, the diagnostic yield was 12% (3/25). There were no useful pathological results in other 22 cases. The difference in the rate of useful pathological results between TBCB group and TBLB group was significant (χ(2)=20.779, P=0.000). There was no pneumothorax or severe bleeding. The rate of mild to moderate bleeding in TBCB group and TBLB group was 47.2%(50/106) and 18.9%(20/106) (χ(2)=19.195, P=0.000) respectively. Conclusion: TBCB is superior to TBLB for lung biopsy as indicated by larger sample size, higher diagnostic yield and less complication. TBCB is valuable for the diagnosis of ILD.

[Homozygous ectonucleotide pyrophosphatase/phosphodiesterase 1 variants in a girl with hypophosphatemic rickets and literature review]

Objective: To investigate the clinical features and genetic characteristics of patients with ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) gene variants. Method: The clinical data of a patient with ENPP1 homozygous variants from Capital Institute of Pediatrics was collected, the related literature was searched from China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, National Center from Biotechnology Information and PubMed by using search term "ENPP1" , "hypophosphatemic rickets" . The literature retrieval was confined from 1980 to February 2017. The clinical manifestations, bone metabolism examinations, X-RAY and genotypes were reviewed. Result: Our patient was an 11 years old girl, with 7 years history of lower limb malformation. She showed significant valgus deformity of the knee (genu valgum). Metabolic examination revealed reduced level of plasma phosphate (0.86 mmol/L), a normal level of plasma calcium (2.30 mmol/L) and an elevated alkaline phosphatase level of 688 IU/L. The calcium-phosphorus product was 25.9. A homozygous nonsense variants of ENPP1 gene, c.783C>G (p.Tyr261X) in exon 7 was identified in the patient. Both parents were heterozygous carriers. Literature review identified 3 Chinese patients from one publication and 17 cases from twenty one publications around the world. None of the patients was found PHEX variants which is the most common variants among hypophosphatemic rickets patients. The disease onset age was 11 months to 10 years. Eight patients had short stature, five patients had the history of generalized arterial calcification of infancy. Four suffered from deafness, three showed localized calcifications of arteries, three patients manifested pseudoxanthoma elasticum and two suffered from ossification of posterior longitudinal ligament. Nine missense variants, six splicing variants and 4 nonsense variants were reported among these twenty patients. c.783C>G was found in two Chinese patients. Conclusion: ENPP1 gene mutation was a cause of patient with hypophosphatemic rickets. Comorbid features included generalized arterial calcification of infancy, early onset hearing loss, pseudoxanthoma and ossification of posterior longitudinal ligament. ENPP1 gene testing should be performed on hypophosphatemic rickets patients without PHEX gene variants. Long-term follow up is recommended. The most common types of ENPP1 gene variants were nonsense/splicing variants. The gene c.783C>G was the most common variants in Chinese patients.

[Clinical manifestation and gene analyses of 15 patients with intellectual disability or developmental delay complicated with congenital nystagmus]

Objective: To analyze the clinical and genetic features of 15 cases with intellectual disability or developmental delay (ID/DD) complicated with congenital nystagmus. Method: The clinical characteristics and the results of laboratory tests, images and genetics of 15 patients with ID/DD complicated with congenital nystagmus, confirmed by gene diagnosis in the Department of Neurology, Children's Hospital Affiliated to Capital Institute of Pediatrics from March 2015 to October 2016, were retrospectively analyzed. The physiological function of 13 disease genes and the molecular signaling pathways were also comparatively studied. Result: The patients included 11 males and four females, with an age of 2 months-15 years (median age 27 months). The result of multiplex ligation-dependent probe amplification was positive in two patients only with hypomyelination on head MRI. Positive results were found in 13 patients with or without abnormal head MRI or other deformities using targeted capture technology and next generation sequencing. Two patients were diagnosed with Pelizaeus-Merzbacher disease, two had hypomyelination with an atrophy of the basal ganglia and cerebellum and two had oculocutaneous albinism. Pelizaeus-Merzbacher-like disease was found in one case, cerebro-oculo-facio-skeletal syndrome in one case, Rubinstein-Taybi syndrome in one case, mental retardation type 5 in one case, methylmalonic aciduria combined with hyperhomocysteinemia in 1 case, ataxia telangiectasia in one case, hypomyelinating leukodystrophy type 8 in one case, Marinesco-Sjögren syndrome in one case and CHARGE syndrome in one case. A total of 12 novo mutations were reported in this study. Conclusion: The causes of children with ID/DD complicated with congenital nystagmusis are complex. Comprehensive clinical and auxiliary examinations should be performed to improve the accuracy of the diagnosis. Reasonable application of different genetic testing methods can significantly improve the diagnostic accuracy of molecular genetic etiology in children with ID/DD.

[Application of negative molds technology based on three-dimensional printing in digital maxillofacial prostheses]

Objective: To explore a digital negative molds technique based on three-dimensional (3D) printing to assist in the manufacture of maxillofacial prostheses, and to improve the deficiency of the current clinical treatment. Methods: Seventeen patients with maxillofacial defects (including nasal defects, orbital defects, cheek defects, auricle defect) were scanned by means of facial optical scanning and computer tomography (CT). The 3D models were then reconstructed and global registration was made to merge the reconstructed models into a new digital model for 3D design. The 3D design of the prostheses was implemented in software. The mechanical connection structure was designed by forward engineering technology for 3 patients with intra-oral defects in maxilla who needed to make removable partial dentures, so that the silicone prostheses and removable partial denture could be combined. The removable partial dentures were made by conventional method and connected with the prostheses. According to the 3D data of the prostheses, the digital negative molds were designed, and the 3D printing technology was used to finish the processing of the resin molds. Silicone for prostheses were filled and cured in the resin molds to fabricate the clinical restorations for the patients. The margin adaptation and retention of the prostheses was detected. Results: Twenty patients with varying degrees of maxillofacial defects were rehabilitated using the courses developed in the study. All patients reported no pain or discomfort during the treatment; and they were satisfied with the final prostheses of the shape, color, retention, stability, etc. Eighteen of the prostheses showed good marginal adaptation, and sixteen of the prostheses showed good retention effect. Conclusions: The digital negative molds technique used in this study could greatly reduce the intensity of manual operation and provided a good therapeutic effect for patients with maxillofacial defects.

[Predictors of rush popper use among 825 men who have sex with men in education in Guangdong Province]

Objective: To explore prevalence and predictors of the use of Rush poppers among men who have sex with men in education in Guangdong Province. Methods: An internet survey was conducted via a gay website from March to August 2014 and a sample of 833 male respondents over 16 years who had ever had anal sex with a male, studied in Guangdong Province and who had completed an online questionnaire was identified- of which 93.4% (n=825) provided valid responses and were included in the study. Respondents provided information on their socio-demographic characteristics, HIV testing history, sexual activity in last 3 months, Rush poppers use and time since first sexual encounter with a male. We used the Chi-squared test and multivariate logistic regression modeling to identify the predictors of Rush poppers use in this population group. Results: Among our sample of 825 MSM, whose ages ranged from 21-27 years, 14.8% (n=122) reported having used Rush poppers in the past 3 months. Rates of use were higher among those who had ever been tested for HIV (16.7% vs. 10.9%, χ²=4.80, P=0.028), had anal intercourse in the last 3 months (16.8% vs. 10.7%, χ²=5.48, P=0.019), had multiple sexual partners in the past 3 months (19.3% vs. 13.1%, χ²=5.14, P=0.023), had a casual partner (18.0% vs. 12.1%, χ²=5.68, P= 0.017) or had a sexually transmitted infection (23.4% vs. 14.0%, χ²=4.85, P=0.028). Those who reported having had their first sexual encounter with another male over 5 years prior had higher rates of use (18.0%) than for those who had been sexually active ≤1 year (10.7%) or 2-4 years (12.5%, χ²=6.41, P=0.041). HIV testing (OR: 1.70, 95% CI: 1.07-2.70), having a casual partner (OR: 1.67, 95% CI: 1.12-2.50) and being sexually active with other males for over 5 years (OR: 1.87, 95%CI: 1.05-3.31) were significantly associated with Rush poppers use. Conclusion: A large proportion of student MSM in Guangdong Province used Rush poppers. Proxy measures of sexual activity such as HIV testing, recent casual sexual encounters and duration of sexual activity were associated with their use.

[Application of " Internet Plus" AIDS prevention services among men who have sex with men in Guangzhou, China: results from 2010 to 2015]

Objective: To introduce the development strategy of " Internet Plus" AIDS prevention services and its implementation results from 2010 to 2015 in Guangzhou, China. Methods: A gay men's health column was created for an active website aimed at men who have sex with men(MSM), in collaboration with local community organizations and the Guangzhou CDC. We designed intervention tools(including scenario-based applications and HIV risk self-assessment systems)and an online HIV testing service platform, integrated with applied psychology and behavioral theory as well as the " Internet Plus" concept, to intervene in HIV infection risk factors among MSM. Data of clients who accessed the " Internet Plus" AIDS services from 2010 to 2015 were used to evaluate service operation. Six-year consecutive surveys, conducted between April and July of each service year, were collected using a national AIDS sentinel surveillance questionnaire. For each year of surveillance, information on HIV prevalence, HIV interventions received during the past year, unprotected anal intercourse in the past 6 months, and HIV testing in the past year were compared using the chi-squared(χ²)test, to roughly reflect the effect of"Internet Plus" AIDS prevention services. Results: As of 31 December 2015, a total of 34 395 MSM had received " Internet Plus" services and HIV testing. The number of MSM tested increased from 2 338 in 2010 to 8 054 in 2015. From 2010 to 2015, newly identified HIV cases in each year were 59, 166, 312, 283, 291, and 270, which accounted for 25.0%, 32.8%, 38.8%, 35.1%, 30.5%, and 23.2% of MSM HIV cases of Guangzhou, respectively. Sentinel surveillance data showed that during the study period, 3 047 MSM were investigated, with 405, 400, 401, 633, 608, and 600 each year, respectively. The proportion of participants who had received any HIV intervention during the past year was 74.3%(301), 70.8%(283), 83.3%(334), 85.0%(538), 69.1%(420), and 83.8%(503)each year, respectively(trend χ²=6.53, P=0.011). HIV testing done during the past year accounted for 44.0%(178), 44.3%(177), 49.4%(198), 53.4%(338), 56.1%(341), and 60.2%(361)each year, respectively(trend χ²=40.83, P<0.001). Unprotected anal intercourse in the past 6 months accounted for 59.3%(240), 62.0%(248), 56.6%(227), 57.0%(361), 48.4%(294), and 43.7%(262)each year, respectively(trend χ²=42.21, P<0.001). Conclusion: The"Internet Plus"AIDS prevention services in this study represent a manner to enhance traditional HIV prevention strategies. We found these services to be effective in implementation of the national AIDS control and prevention strategy, especially for the expansion of intervention, testing, and case identification among high-risk populations.

Comparison and analysis of Wuding and avian chicken skeletal muscle satellite cells

Chicken skeletal muscle satellite cells are located between the basement membrane and the sarcolemma of mature muscle fibers. Avian broilers have been genetically selected based on their high growth velocity and large muscle mass. The Wuding chicken is a famous local chicken in Yunnan Province that undergoes non-selection breeding and is slow growing. In this study, we aimed to explore differences in the proliferation and differentiation properties of satellite cells isolated from the two chicken breeds. Using immunofluorescence, hematoxylin-eosin staining and real-time polymerase chain reaction analysis, we analyzed the in vitro characteristics of proliferating and differentiating satellite cells isolated from the two chicken breeds. The growth curve of satellite cells was S-shaped, and cells from Wuding chickens entered the logarithmic phase and plateau phase 1 day later than those from Avian chicken. The results also showed that the two skeletal muscle satellite cell lines were positive for Pax7, MyoD and IGF-1. The expression of Pax7 followed a downward trend, whereas that of MyoD and IGF-1 first increased and subsequently decreased in cells isolated from the two chickens. These data indicated that the skeletal muscle satellite cells of Avian chicken grow and differentiate faster than did those of Wuding chickens. We suggest that the methods of breeding selection applied to these breeds regulate the characteristics of skeletal muscle satellite cells to influence muscle growth.

A Method Based on Bottleneck-Linear Assignment for Forming Complex Transport Formations

Cooperative transportation using multi-robots is a significant challenge in robotics. For the problem, each robot is required, in general, to reach a different task-point to form a transport formation, where all the task-points are determined according to the shape of the transported object and the number of robots. A method based on bottleneck-linear assignment is proposed to form complex transport formations. First, the optimal paths from each robot to all the task-points are calculated by a two-direction path algorithm, which is developed in this paper as the core of the task-points' assignment. Second, in order to optimize the travelling paths of the robots and the time taken to establish the formation, a bottleneck-linear assignment strategy is presented to assign the task-points for the robots. Finally, an improved artificial moment motion controller makes each robot move along a sub-optimal path to reach its task-point. Simulations indicate that the proposed method is feasible and efficient.

3D Printed Microtransporters: Compound Micromachines for Spatiotemporally Controlled Delivery of Therapeutic Agents

Functional compound micromachines are fabricated by a design methodology using 3D direct laser writing and selective physical vapor deposition of magnetic materials. Microtransporters with a wirelessly controlled Archimedes screw pumping mechanism are engineered. Spatiotemporally controlled collection, transport, and delivery of micro particles, as well as magnetic nanohelices inside microfluidic channels are demonstrated.

Protective role of selenium-enriched supplement on spinal cord injury through the up-regulation of CNTF and CNTF-Ralpha

OBJECTIVE

Spinal cord injury (SCI), as one of the common serious spine disorders, often leads to severe neurological dysfunction and even permanent disability, which will cause heavy economical burden for family and society. Currently, selenium-enriched products have an obvious role in the protection and recovery of SCI; however, its protective mechanism is still unclear.

MATERIALS AND METHODS

In order to explore the protective effect of selenium-enriched supplement (SES) on SCI, the adult rats were randomly divided into sham operation control (SC) group, ischemia-reperfusion model (IM) group and SES pretreatment (ST) group to investigate the change of ciliary neurotrophic factor (CNTF) and its receptor-alpha (CNTF-Ralpha) during SCI in the presence of SES. The rats in IM and ST groups were subjected to the blockage of their abdominal aorta to establish the model of SCI; but the rats in SC group were subjected to sham operation without the blockage of abdominal aorta. The rats in ST group were fed with foods containing SES at the dose of equivalent 5 mg/L selenium in water before blocking their abdominal aorta. After 7 days, the rats were sacrificed to observe the structure of nerve cells through HE staining and the expression of CNTF and CNTF-Ralpha by Western blot, immunohistochemical, and RT-PCR methods, respectively.

RESULTS

Both protein and mRNA of CNTF and CNTF-Ralpha were positively expressed in rats from SC group. The mRNA expression levels of CNTF and CNTF-Ralpha in ST group were much higher than SCI model group.

CONCLUSIONS

SES can execute a protective role in SCI through up-regulating the expression of CNTF and CNTF-Ralpha.

An in vitro study of peptide-loaded alginate nanospheres for antagonizing the inhibitory effect of Nogo-A protein on axonal growth

The adult mammalian central nervous system has limited ability to regenerate after injury. This is due, in part, to the presence of myelin-associated axon growth inhibitory proteins such as Nogo-A that bind and activate the Nogo receptor, leading to profound inhibition of actin-based motility within the growing axon tip. This paper presents an in vitro study of the use of a Nogo receptor-blocking peptide to antagonize the inhibitory effect of Nogo-A on axon growth. Alginate nanospheres were fabricated using an emulsion technique and loaded with Nogo receptor-blocking peptide, or with other model proteins. Protein release profiles were studied, and retention of the bioactivity of released proteins was verified. Primary dorsal root ganglion neurons were cultured and their ability to grow neurites was challenged with Nogo-A chimeric protein in the absence or presence of Nogo receptor antagonist peptide-loaded alginate nanospheres. Our results demonstrate that peptide released from alginate nanospheres could overcome the growth inhibitory effect of Nogo-A, suggesting that a similar peptide delivery strategy using alginate nanospheres might be used to improve axon regeneration within the injured central nervous system.

PLGA/alginate composite microspheres for hydrophilic protein delivery

Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate.

A mathematical model and computational framework for three-dimensional chondrocyte cell growth in a porous tissue scaffold placed inside a bi-directional flow perfusion bioreactor

The in vitro chondrocyte cell culture for cartilage tissue regeneration in a perfusion bioreactor is a complex process. Mathematical modeling and computational simulation can provide important insights into the culture process, which would be helpful for selecting culture conditions to improve the quality of the developed tissue constructs. However, simulation of the cell culture process is a challenging task due to the complicated interaction between the cells and local fluid flow and nutrient transport inside the complex porous scaffolds. In this study, a mathematical model and computational framework has been developed to simulate the three-dimensional (3D) cell growth in a porous scaffold placed inside a bi-directional flow perfusion bioreactor. The model was developed by taking into account the two-way coupling between the cell growth and local flow field and associated glucose concentration, and then used to perform a resolved-scale simulation based on the lattice Boltzmann method (LBM). The simulation predicts the local shear stress, glucose concentration, and 3D cell growth inside the porous scaffold for a period of 30 days of cell culture. The predicted cell growth rate was in good overall agreement with the experimental results available in the literature. This study demonstrates that the bi-directional flow perfusion culture system can enhance the homogeneity of the cell growth inside the scaffold. The model and computational framework developed is capable of providing significant insight into the culture process, thus providing a powerful tool for the design and optimization of the cell culture process.

Computational modelling of the scaffold-free chondrocyte regeneration: a two-way coupling between the cell growth and local fluid flow and nutrient concentration

The in vitro chondrocyte cell culture process in a perfusion bioreactor provides enhanced nutrient supply as well as the flow-induced shear stress that may have a positive influence on the cell growth. Mathematical and computational modelling of such a culture process, by solving the coupled flow, mass transfer and cell growth equations simultaneously, can provide important insight into the biomechanical environment of a bioreactor and the related cell growth process. To do this, a two-way coupling between the local flow field and cell growth is required. Notably, most of the computational and mathematical models to date have not taken into account the influence of the cell growth on the local flow field and nutrient concentration. The present research aimed at developing a mathematical model and performing a numerical simulation using the lattice Boltzmann method to predict the chondrocyte cell growth without a scaffold on a flat plate placed inside a perfusion bioreactor. The model considers the two-way coupling between the cell growth and local flow field, and the simulation has been performed for 174 culture days. To incorporate the cell growth into the model, a control-volume-based surface growth modelling approach has been adopted. The simulation results show the variation of local fluid velocity, shear stress and concentration distribution during the culture period due to the growth of the cell phase and also illustrate that the shear stress can increase the cell volume fraction to a certain extent.

Modelling and simulation of the chondrocyte cell growth, glucose consumption and lactate production within a porous tissue scaffold inside a perfusion bioreactor

Mathematical and numerical modelling of the tissue culture process in a perfusion bioreactor is able to provide insight into the fluid flow, nutrients and wastes transport, dynamics of the pH value, and the cell growth rate. Knowing the complicated interdependence of these processes is essential for optimizing the culture process for cell growth. This paper presents a resolved scale numerical simulation, which allows one not only to characterize the supply of glucose inside a porous tissue scaffold in a perfusion bioreactor, but also to assess the overall culture condition and predict the cell growth rate. The simulation uses a simplified scaffold that consists of a repeatable unit composed of multiple strands. The simulation results explore some problematic regions inside the simplified scaffold where the concentration of glucose becomes lower than the critical value for the chondrocyte cell viability and the cell growth rate becomes significantly reduced.

A comprehensive, prospective study of penile dimensions in Chinese men of multiple ethnicities

This study aimed to establish a reference range of penile length and circumference of adult males in China, and to compare the penile dimensions of different ethnical backgrounds. To do this, penile length and circumference measurements were obtained from 5196 healthy males attending the Urology Counseling Clinic. The mean value of penile dimensions was a flaccid length of 6.5 ± 0.7 cm, a stretched length of 12.9 ± 1.2 cm and a flaccid circumference of 8.0 ± 0.8 cm. In the subgroup of 311 males, the mean erectile length was 12.9 ± 1.3 cm and the mean erectile circumference was 10.5 ± 0.9 cm, the mean flaccid and erectile glans lengths were 2.7 ± 0.3 and 3.4 ± 0.4 cm, respectively, and the mean flaccid and erectile glans diameters were 2.6 ± 0.2 and 3.4 ± 0.4 cm, respectively. We found that flaccid penile length and circumference varied among different ethnicities. This study established a reference range for penile dimensions, which will help when counseling patients worried about their penile size or seeking penis enlargement surgery. We also found that penile dimensions are different in different ethnicities, but further investigations are needed to validate this.

Investigation of the in vitro culture process for skeletal-tissue-engineered constructs using computational fluid dynamics and experimental methods

The in vitro culture process via bioreactors is critical to create tissue-engineered constructs (TECs) to repair or replace the damaged tissues/organs in various engineered applications. In the past, the TEC culture process was typically treated as a black box and performed on the basis of trial and error. Recently, computational fluid dynamics (CFD) has demonstrated its potential to analyze the fluid flow inside and around the TECs, therefore, being able to provide insight into the culture process, such as information on the velocity field and shear stress distribution that can significantly affect such cellular activities as cell viability and proliferation during the culture process. This paper briefly reviews the CFD and experimental methods used to investigate the in vitro culture process of skeletal-type TECs in bioreactors, where mechanical deformation of the TEC can be ignored. Specifically, this paper presents CFD modeling approaches for the analysis of the velocity and shear stress fields, mass transfer, and cell growth during the culture process and also describes various particle image velocimetry (PIV) based experimental methods to measure the velocity and shear stress in the in vitro culture process. Some key issues and challenges are also identified and discussed along with recommendations for future research.

Cooperative manipulation and transport of microobjects using multiple helical microcarriers

We report a cooperative transport strategy that uses engineered microbars and multiple helical microcarriers. Cooperation of microcarriers generates higher propulsive forces while application of forces at multiple locations results in motion control with multiple degrees of freedom.

Prostanoid EP₁ receptors mediate up-regulation of the orphan nuclear receptor Nurr1 by cAMP-independent activation of protein kinase A, CREB and NF-κB

BACKGROUND AND PURPOSE

Prostaglandin E(2) (PGE(2)) stimulation of the G protein-coupled prostanoid EP(1) receptor was found to up-regulate the expression of Nur-related factor 1 (Nurr1) (NR4A2), a transcription factor in the NR4A subfamily of nuclear receptors. The present studies characterize the molecular mechanism of this up-regulation.

EXPERIMENTAL APPROACH

The expression of Nurr1 was examined by immunoblot analysis, the polymerase chain reaction and reporter gene assays in human embryonic kidney (HEK) cells stably expressing the recombinant EP(1) receptor and in SH-SY5Y neuroblastoma cells expressing endogenous EP(1) receptors. Signalling pathway inhibitors were used to examine the roles of Rho, PKA, the cAMP response element binding protein (CREB) and NF-κB on the PGE(2) stimulated up-regulation of Nurr1. CREB and NF-κB signalling were also examined by immunoblot analysis and reporter gene assays.

KEY RESULTS

The EP(1) receptor mediated up-regulation of Nurr1 was blocked with inhibitors of Rho, PKA, NF-κB and CREB; but PGE(2) failed to significantly stimulate intracellular cAMP formation. PGE(2) stimulation of the EP1 receptor induced the phosphorylation and activation of CREB and NF-κB, which could be blocked by inhibition of PKA.

CONCLUSIONS AND IMPLICATIONS

PGE(2) stimulation of the human EP(1) receptor up-regulates the expression of Nurr1 by a mechanism involving the sequential activation of the Rho, PKA, CREB and NF-κB signalling pathways. EP(1) receptors are implicated in tumorigenesis and the up-regulation of Nurr1 may underlie the anti-apoptotic effects of PGE(2) .

Modeling of cell cultures in perfusion bioreactors

Cultivating cells and tissues in bioreactors is a critical step in forming artificial tissues or organs prior to transplantation. Among various bioreactors, the perfusion bioreactor is known for its enhanced convection through the cell-scaffold constructs. Knowledge of mass transfer is essential for controlling the cell culture process; however, obtaining this information remains a challenging task. In this research, a novel mathematical model is developed to represent the nutrient transport and cell growth in a 3-D scaffold cultivated in a perfusion bioreactor. Numerical methods are employed to solve the equations involved, with a focus on identifying the effect of factors such as porosity, culturing time, and flow rate, which are controllable in the scaffold fabrication and culturing process, on cell cultures. To validate the new model, the results from the model simulations were compared to the experimental results extracted from the literature. With the validated model, further simulations were carried out to investigate the glucose and oxygen distribution and the cell growth within the cell-scaffold construct in a perfusion bioreactor, thus providing insight into the cell culture process.

Aerodynamic effects of inferior turbinate surgery on nasal airflow--a computational fluid dynamics model

BACKGROUND

Turbinate reduction surgery may be indicated for inferior turbinate enlargement when conservative treatment fails. The aim of this study was to evaluate the effects of inferior turbinate surgery on nasal aerodynamics using computational fluid dynamics (CFD) simulations.

METHODS

CFD simulations were performed for the normal nose, enlarged inferior turbinate and following three surgical procedures: (1) resection of the lower third free edge of the inferior turbinate, (2) excision of the head of the inferior turbinate and (3) radical inferior turbinate resection. The models were constructed from MRI scans of a healthy human subject and a turbulent flow model was used for the numerical simulation. The consequences of the three turbinate surgeries were compared with originally healthy nasal model as well as the one with severe nasal obstruction.

RESULTS

In the normal nose, the bulk of streamlines traversed the common meatus adjacent to the inferior and middle turbinate in a relatively vortex free flow. When the inferior turbinate was enlarged, the streamlines were directed superiorly at higher velocity and increased wall shear stress in the nasopharynx. Of the three surgical techniques simulated, wall shear stress and intranasal pressures achieved near-normal levels after resection of the lower third. In addition, airflow streamlines and turbulence improved although it did not return to normal conditions. As expected, radical turbinate resection resulted in intra-nasal aerodynamics of atrophic rhinitis demonstrated in previous CFD studies.

CONCLUSION

There is little evidence that inspired air is appropriately conditioned following radical turbinate surgery. Partial reduction of the hypertropic turbinate results in improved nasal aerodynamics, which was most evident following resection of the lower third. The results were based on a single individual and cannot be generalised without similar studies in other subjects.

Synthesis of erbium oxide nanosheets and up-conversion properties

A novel erbium-based compound as well as Er(2)O(3) nanosheets have been synthesized through a simple hydrothermal route. The nanosheets are of 200 nm width and 10-15 nm thickness. It is suggested that this erbium-based compound has a possible formula of Er(2)O(5)H(4) with a primitive tetragonal structure (cell parameters: a = 8.465(1) and c = 15.117(2) Å). Face-centered cubic and body-centered cubic structured Er(2)O(3) nanosheets were obtained after calcination of this compound at 623 and 973 K, respectively, both having a paramagnetic behavior. Er(2)O(5)H(4) and Er(2)O(3) nanosheets have similar up-conversion properties with strong blue emission, which is rarely reported in the literature. The existence of absorbed surface contaminations in nanosheets might be the origin for the blue emission enhancement.