[Analysis on early predictors of respiratory depression in patients with glufosinate poisoning]

Objective: To investigate the early predictors of respiratory depression in patients with glufosinate poisoning, and provide reference for clinicians to make decisions. Methods: In March 2022, the clinical data of patients with glufosinate poisoning admitted to the intensive care unit of the Affiliated Xiangshan Hospital of Wenzhou Medical University from March 2018 to January 2022 were retrospectively analyzed. The patients were divided into respiratory depression group and non-respiratory depression group according to the occurrence of respiratory depression during hospitalization. The clinical data such as age, gender, past history, intake, initial treatment and laboratory examination were compared between the two groups. Multivariate logistic regression was used to analyze the predictors of respiratory depression in patients with glufosinate poisoning, and its predictive value was analyzed by receiver operating characteristic (ROC) curve. Results: A total of 34 patients with glufosinate poisoning were enrolled, including 13 patients in non-respiratory depression group and 21 patients in respiratory depression group. There were significant differences in intake, blood amylase and bicarbonate radical in arterial blood gas between the two groups (P<0.05). Respiratory depression occurred at 6.5-48.0 h after ingestion, with a median of 15.0 (9.5, 24.0) h. Multivariate logistic regression analysis showed that the intake of glufosinate (OR=1.440, 95%CI: 1.033-2.009, P=0.032) and bicarbonate radical in arterial blood gas (OR=0.199, 95%CI: 0.040-0.994, P=0.049) were predictors of respiratory depression in patients with glufosinate poisoning, and the area under the curve (AUC) of ROC curves were 0.936 and 0.842. The optimal cut-off values were 15.0 g (sensitivity=95.2%, specificity=76.9%) and 17.6 mmol/L (sensitivity=71.4%, specificity=84.6%), respectively. Conclusion: The intake of glufosinate and bicarbonate radical in arterial blood gas have good prediction effects on the occurrence of respiratory depression in patients with glufosinate poisoning.

[Clinical significance of intersphincteric resection related anatomy effect on surgical safety]

The anatomical studies of intersphincteric resection (ISR) have made remarkable progress in recent years. The anatomy of internal, external sphincter and hiatal ligament has been further understood. In this paper, the generation and functional mechanism of ISR related anatomy are described from the embryonic development process, and then the influence of hiatal ligament and internal sphincter on ISR surgery is analyzed respectively according to the anatomical characteristics. Finally, the correlation analysis of anatomical factors on the common problems of mucosal bleeding and instrument anastomosis in ISR is carried out. The objective of this paper is to improve the safety of ISR surgery by providing detailed anatomical explanations.

[Recognition of surgical anatomy for intersphincteric resection]

Intersphincteric resection (ISR) involves the anatomy of hiatal ligament, internal and external sphincter and conjoined longitudinal muscle. The hiatal ligament is actually a branch of the longitudinal muscle of rectum, shown as an uneven ring attached to the levator ani muscle. The internal sphincter is the end of the circular muscle of rectum which begins at the level of hiatal ligament formation. The distance from the upper boundary of internal sphincter to dentate line is significantly different among individuals. Although there is adipose tissue in the space between the internal and external sphincters, no evidence of mesentery structure in the anal canal is found as in the rectum. The conjoined longitudinal muscle is the remaining branch of the longitudinal muscle, whose return passes through the external sphincter and ends at the anococcygeal ligament/coccyx after reaching the anal margin. The synergistic action of conjoined longitudinal muscle and the hiatal ligament participates in the defecation process. The individualized difference of ISR-related anatomy affects the operation, especially the anastomosis.

[The diagnostic performance of galactomannan detection in invasive pulmonary aspergillosis with severe and critically ill influenza]

Objective: To analyze the diagnostic performance of serum and bronchoalveolar lavage fluid (BALF) galactomannan (GM) test in invasive pulmonary aspergillosis(IPA) with severe and critically ill influenza. Methods: A retrospective study was performed for 157 patients with severe and critically ill influenza admitted to the Department of Pulmonary and Critical Care Medicine of the First Affiliated Hospital of Wenzhou Medical University from December 2017 to April 2019.Clinical characteristics and serum and BALF GM values were collected. The patients were divided into an IPA group (n=18) and a non-IPA group (n=139). The definition of IPA modified from AspICU algorithm taken as the gold standard (The corresponding clinical manifestations, imaging manifestations and microbiological diagnostic criteria should be met simultaneously), the performance of serum and BALF GM test and their combination to IPA with influenza were analyzed respectively and receiver operating characteristic curve (ROC) was drawn. Results: A total of 157 cases were enrolled, 95 were critically ill, and the mortality of IPA with influenza was 55.6%(10/18). The APACHE Ⅱ score, PSI score, urea nitrogen, influenza severity (Percentage of critically ill influenza) and invasive ventilator in IPA group were (16±6), (110±31), 10.7 (8.4, 17.8) mmol/L, 88.9% and 66.7%, respectively, which were significantly higher than those in non-IPA group [(10±5), (83±30), 5.2 (3.6, 7.6) mmol/L, 56.8% and 24.5%, P<0.05]. All patients received serum GM test and 32 patients performed BALF GM test at the same time. When the cut-off valve of serum GM test was 0.5 μg/L, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 66.7% (12/18), 95.0% (132/139), 63.2% (12/19) and 95.7% (132/138) respectively. When the cut-off value of BALF GM test was 1.0 μg/L, the sensitivity, specificity, PPV and NPV were 80%(8/10),86.4%(19/22),72.7%(8/11)and 90.5%(19/21)respectively. The BALF GM cut-off value of 0.88 μg/L showed the highest diagnostic efficacy for IPA, for which the sensitivity and specificity were 90%(9/10) and 86.4%(19/22). The areas under the ROC curve of serum GM, BALF GM, and the combination of them were 0.81, 0.85, and 0.94 respectively. The difference was statistically significant (P<0.05) and the combined diagnosis efficiency was higher. Conclusions: Critically ill influenza patients should be alert for IPA. The sensitivity of serum GM test in the diagnosis of IPA with influenza was low, while the NPV was high. The optimum BALF GM cut-off value was 0.88 μg/L. The combination with BALF and serum GM test can improve the diagnostic performance.

[Role of Orai 1-mediated store-operated calcium entry in the immune function of CD4+ T cells in septic mice]

Objective: To investigate the role of Orai1-mediated store-operated calcium entry in the immune damage of CD4⁺ T cells in septic mice. Methods: Sepsis mouse model was established by cecal ligation and puncture(CLP). Balb/c mice of clean grade were sacrificed 1, 3, and 5 days after operation. Spleen samples were harvested at given intervals. Splenic CD4⁺ T cells were selected by immunomagnetic beads and the expression of Orai1 protein was detected by western blotting, the storage operated calcium entry (SOCE) was detected by flow cytometry, the apoptosis of CD4⁺ T cells was detected by flow cytometry, the proliferation of CD4⁺ T cells was detected by CCK-8, and the IFN-γ and IL-4 were detected by enzyme-linked immunosorbent assay (ELISA). Then the expression of Orai1 protein was regulated to further detect the SOCE and immune function of splenic CD4⁺ T cells in mice. The experiment was divided into 4 groups, sham group, CLP3 group, Orai1 down group (Orai1-down group) and Orai1 up regulation group (Orai1-up group). Results: The relative expression of Orai1 protein in splenic CD4⁺ T cells in sham group was 1.03±0.16. Compared with sham group, Orai1 protein levels in CLP Group were all significantly lower (F=19.64, P=0.000 5). The increased value of splenic CD4⁺ T cells fluorescence intensity in sham group was 494±41. Compared with sham group, the levels of SOCE in CLP Group were all lower (F=30.01, P=0.001). The ratio of early and late apoptosis of CD4⁺ T cells in sham group was 8.7%±1.5%. Compared with sham group, the early and late apoptosis rates of CLP Group were significantly higher (F=32.29, P=0.000 1). The OD of sham group was 0.81±0.10 at 450 nm. Compared with sham group, the proliferation ability of splenic CD4⁺ T cells in CLP Group were significantly decreased (F=7.26, P=0.001 8). Compared with sham group, the secretion of IFN-γ and IL-4 by CD4⁺ T cells and the ratio of IFN-γ/IL-4 in CLP Group were all significantly decreased (F=19.690, 6.183, 11.230, all P<0.05). Compared with CLP3 group, the increased value of fluorescence intensity of CD4⁺ T cells was significantly decreased, the early and late apoptosis ratio of CD4⁺ T cells was significantly increased, the OD450 nm value of CD4⁺ T cells was decreased, the multiplication capacity of splenic CD4⁺ T cells were decreased, the level of IFN-γ and IL-4 secreted by T cells were decreased, and the value of IFN-γ/IL-4 in orai1-down group was decreased (t=4.819, 7.952, 2.988, 28.760, 3.140, 7.670, all P<0.05). However, Orail-up group showed the opposite trend. Conclusion: Orai1-mediated store-operated calcium entry can alleviate the immune dysfunction of CD4⁺ T cells in septic mice.

Interventional treatment of arterial injury during blind central venous catheterisation in the upper thorax: experience from two centres

AIM

To evaluate the safety and clinical efficacy of interventional treatment for arterial injury during blind, central venous catheterisation in the upper thorax at two tertiary medical centres.

MATERIALS AND METHODS

Eighteen consecutive patients (37-81 years; M:F=8:10) who underwent interventional treatment for the arterial injuries that occurred during central venous catheterisation without any imaging guidance between November 2007 and December 2018 were included. Clinical data, angiographic findings, detailed interventional procedures, and technical and clinical outcomes were analysed retrospectively.

RESULTS

Arterial injury sites were the subclavian artery/branches (n=12), axillary artery/branches (n=2), and common carotid artery (n=4). The target vein was not correlated with the corresponding artery/branches in eight patients (44.4%); internal jugular vein to subclavian artery branches. Angiographic findings were pseudoaneurysm (66.7%, 12/18), contrast medium extravasation (22.2%, 4/18), or both (11.1%, n=2). A stent graft was inserted for the main trunk injuries in nine patients, with (n=2) or without (n=7) prior arterial branch embolisation to prevent potential endoleak, while embolisation for the arterial branch injuries was performed in nine patients. Direct percutaneous access with thrombin injection to the pseudoaneurysm or residual arteriovenous fistula was utilised in two. The technical and clinical success rate was 94.4% (17/18) each. There were no procedure-related complications. In one patient without immediate clinical success, there was a persistent pseudoaneurysm after stent graft placement, which was treated with in-stent balloon dilation.

CONCLUSION

Interventional treatment serves as a safe and effective treatment modality for inadvertent arterial injury related to blind, central venous access catheterisation in the upper thorax.

Vancomycin-loaded oxidized hyaluronic acid and adipic acid dihydrazide hydrogel: Bio-compatibility, drug release, antimicrobial activity, and biofilm model

BACKGROUND

Prosthesis infection is a difficult-to-treat situation. Hydrogel is a novel biomaterial, which can be applied by simply spraying or by coating on implants before surgery and can be easily mixed with antibiotics.

METHODS

In order to evaluate the potential use of antibiotic-loaded hydrogel, we incorporated vancomycin into oxidized hyaluronic acid (HA) and adipic acid dihydrazide and evaluated the drug release and antimicrobial activity against methicillin-resistant Staphylococcus aureus (ATCC 29213).

RESULTS

The average release percentage of vancomycin on day 3 was about 86%. The antibiotic-loaded gel was biocompatible with mesenchymal stem cell, MC3T3, and L929 cell lines. The in vitro inhibition zones of vancomycin-loaded hydrogel [500X minimal inhibition concentration (MIC), 50X MIC, 10X MIC, and blank hydrogel] were 21, 13, 9, and 5 mm, respectively. In the Ti6Al4V implant biofilm model, 0.01-1% vancomycin-loaded gel exhibited significant anti-biofilm activity, measured by the MTT assay.

CONCLUSIONS

Vancomycin could be loaded onto oxidized HA and adipic acid dihydrazide, which exhibited excellent drug release and in vitro antimicrobial activity with minimal cell toxicity.

[Diagnostic performance of T-SPOT.TB on peripheral blood in combination with adenosine deaminase on pleural fluid for the diagnosis of tuberculous pleurisy within different age group]

Objective: To evaluate the performance of T cell enzyme-linked immuno-spot assay (T-SPOT) on peripheral blood in combination with adenosine deaminase (ADA) on pleural fluid for diagnosis of tuberculous (TB) pleurisy within different age groups. Methods: The data of patients with pleural effusion from the Department of Pulmonary and Critical Care Medicine of the First Affiliated Hospital of Wenzhou Medical University from April 2012 to November 2016 were retrospectively analyzed, and the diagnoses of these patients were histopathologically confirmed through medical thoracoscopy. The cases who had confirmed diagnosis, in the same time, received peripheral blood T-SPOT.TB were enrolled. The performance of peripheral blood T-SPOT.TB in combination with pleural fluid ADA on diagnosing TB pleurisy in the younger patients (16-59 years old) and elderly patients (≥60 years old) were analyzed respectively. The sensitivity, specificity and the receiver operating characteristic (ROC) curve were adopted for statistical analysis. Results: A total of 448 cases were finally enrolled, 341(76.1%) confirmed with TB pleurisy, 224 males, 117 females, (47±19) years old; and 107 (23.9%) classified as non-TB pleurisy, 65 males, 42 females, (61±14) years old. There were 285 cases who were classified as younger group, and the other 163 cases were classified as elderly group. The sensitivity and specificity of peripheral blood T-SPOT.TB were 85.4% (204/239) and 71.7% (33/46) in the younger patients, 76.5% (78/102) and 59.0% (36/61) respectively in the elderly patients. The sensitivity of peripheral blood T-SPOT.TB in the younger patients was significantly higher than that in the elderly patients (P=0.047). The sensitivity and specificity were 99.2% and 95.7% in combination with peripheral blood T-SPOT.TB and pleural fluid ADA respectively in the younger patients. The area under ROC curve (AUC) of T-SPOT.TB in the younger patients was 0.833, AUC of T-SPOT.TB combined with ADA was 0.911. The combination test of 2 tests had the sensitivity of 96.1% and the specificity of 90.2% respectively in the elderly patients. The AUC of T-SPOT.TB in the elderly patients was 0.747, AUC of T-SPOT.TB combined with ADA was 0.911. Conclusion: Peripheral blood T-SPOT.TB combined with pleural fluid ADA can improve the diagnostic performance for TB pleurisy with different ages, especially for elderly patients who can't tolerate pleural biopsy.

[The diagnostic performance of galactomannan detection for invasive pulmonary aspergillosis in non-neutropenic hosts]

Objective: To evaluate the diagnostic performance of galactomannan(GM)detection in serum and BALF for invasive pulmonary aspergillosis (IPA) in non-neutropenic hosts. Methods: A pospective study was performed for 1 356 non-neutropenic hosts admitted to the Department of Pulmonary and Critical Care Medicine of the First Affiliated Hospital of Wenzhou Medical University from September 2014 to October 2015. Serum GM test was performed for all, and BALF GM test for a proportion of the patients. The patients were divided into an IPA group and a non-IPA group. SPSS 20.0 was adopted for statistical analysis. Results: A total of 1 361 cases were enrolled, aging 18-96 years, with an average age of (64±15) years. There were 879 male and 477 female patients. Thirty-nine cases were diagnosed as IPA, accounting for 2.9%. For serum GM test, the sensitivity, specificity, PPV and NPV were 43.6%(17/39), 94.1%(1 239/1 317), 17.9%(17/95)and 98.3%(1 239/1 261)respectively. Ninety-six cases received serum and BALF GM tests at the same time. If the cut-off value of BALF GM test was 0.8, the sensitivity, specificity, PPV and NPV were 86.7%(13/15), 60.5%(49/81), 28.9%(13/45), 96.1%(49/51)respectively, but if the value was 1.0, the sensitivity, specificity, PPV and NPV were 86.7%(13/15), 74.1%(60/81), 38.2%(13/34), 96.8%(60/62)respectively. The ROC curve area of BALF GM, serum GM and the combined serum and BALF GM was 0.87, 0.75 and 0.90, respectively. Conclusions: The sensitivity of serum GM test in non-neutropenic hosts was low, but it had a high negative predictive value.The best BALF GM cut-off value was 1.0. The combined serum and BALF GM tests improved the diagnostic performance.

Evaluation of New Biphasic Calcium Phosphate Bone Substitute: Rabbit Femur Defect Model and Preliminary Clinical Results

Autogenous bone grafting, used to repair bone defects, is limited and the donor site can experience complications. Compared to autogenous bone graft, artificial bones have different porosity, which might make them suitable alternatives to bone grafts. Here, two porous biphasic calcium phosphate bone substitutes, namely Bicera™ and Triosite™, are used in an animal study and clinical practice to find a suitable porosity for implantation. Bicera™ and Triosite™ consist of 60 wt% hydroxyapatite and 40 wt% β-tricalcium phosphate, with the porosity of Bicera™ (82%) being higher than that of Triosite™ (70%). In the animal study, the implantation procedure was carried out on twenty-four female New Zealand rabbits. 12 weeks after implantation, the new bones were well infiltrated into the Bicera™ and Triosite™ bone grafts. In the clinical study, patients with comminuted fracture, fracture nonunion, or arthrodesis were included in the study of bone substitution with Bicera™. 27 patients underwent fracture fixation treatment. Bone healing of 22.22% (6/27) of patients happened within 3 months after the surgery, and that of 66.67% (18/27) of patients happened within 6 months. These results reveal that Bicera™ has good incorporation with host bone, and that new bone is able to grow within the porous structure, giving it high potential in the treatment of bone defects.

Population genetic structure of critically endangered salamander (Hynobius amjiensis) in China: recommendations for conservation

Amji's salamander (Hynobius amjiensis) is a critically endangered species (IUCN Red List), which is endemic to mainland China. In the present study, five haplotypes were genotyped for the mtDNA cyt b gene in 45 specimens from three populations. Relatively low levels of haplotype diversity (h = 0.524) and nucleotide diversity (π = 0.00532) were detected. Analyses of the phylogenic structure of H. amjiensis showed no evidence of major geographic partitions or substantial barriers to historical gene flow throughout the species' range. Two major phylogenetic haplotype groups were revealed, and were estimated to have diverged about 1.262 million years ago. Mismatch distribution analysis, neutrality tests, and Bayesian skyline plots revealed no evidence of dramatic changes in the effective population size. According to the SAMOVA and STRUCTURE analyses, H. amjiensis should be regarded as two different management units.

Effects of co-fermented Pleurotus eryngii stalk residues and soybean hulls by Aureobasidium pullulans on performance and intestinal morphology in broiler chickens

Soybean hulls are a by-product of soybean processing for oil and meal production; Pleurotus eryngii stalk residues (PESR) are by-products of the edible portion of the fruiting body enriched in bioactive metabolites. This study evaluated the effects of co-fermented PESR and soybean hulls with Aureobasidium pullulans on performance and intestinal morphology in broiler chickens. The in vitro experimental results showed that xylananse and mannanase activity of solid-state fermented soybean hulls (100% SBH) and soybean hulls partially replaced with PESR (75:25, SHP) reached peak at day 12; solid-state fermentation (SSF) enhanced the total phenolic content and trolox equivalency in both products as well. Additionally, FSHP had higher xylotriose and mannobiose levels than fermented FSBH did. A total of 400 broilers (Ross 308) were assigned randomly into four groups receiving the basal diet (control) or the basal diet supplemented with 0.5% fermented SBH (0.5% FSBH), 0.5% fermented SBHP (0.5% FSHP) and 1.0% fermented SBHP (1.0% FSHP) until 35 d of age, respectively. Results demonstrated that 0.5% FSHP addition increased body weight gain as compared with corresponding normal diet fed control in birds during entire experimental period. Compared with the control group, 0.5% FSHP group significantly increased the ratio of lactic acid bacteria to Clostridium perfringens in ceca as well as ileum villus height and jejunum villus height/crypt depth ratio of 35 d old birds. In conclusion, 0.5% FSHP supplementation in the diet could obtain not only improved body weight gain, but optimal intestinal morphology by exerting its bioactive metabolite properties when fed to broilers.

Simulation of thermal ablation by high-intensity focused ultrasound with temperature-dependent properties

An integrated computational framework was developed in this study for modeling high-intensity focused ultrasound (HIFU) thermal ablation. The temperature field was obtained by solving the bioheat transfer equation (BHTE) through the finite element method; while, the thermal lesion was considered as a denatured material experiencing phase transformation and modeled with the latent heat. An equivalent attenuation coefficient, which considers the temperature-dependent properties of the target material and the ultrasound diffraction due to bubbles, was proposed in the nonlinear thermal transient analysis. Finally, a modified thermal dose formulation was proposed to predict the lesion size, shape and location. In-vitro thermal ablation experiments on transparent tissue phantoms at different energy levels were carried out to validate this computational framework. The temperature histories and lesion areas from the proposed model show good correlation with those from the in-vitro experiments.

Application of multiple levels of fluid shear stress to endothelial cells plated on polyacrylamide gels

Measurements of endothelial cell response to fluid shear stress have previously been performed on unphysiologically rigid substrates. We describe the design and implementation of a microfluidic device that applies discrete levels of shear stress to cells plated on hydrogel-based substrates of physiologically-relevant stiffness. The setup allows for measurements of cell morphology and inflammatory response to the combined stimuli, and identifies mechanisms by which vascular stiffening leads to pathological responses to blood flow. We found that the magnitude of shear stress required to affect endothelial cell morphology and inflammatory response depended on substrate stiffness. Endothelial cells on 100 Pa substrates demonstrate a greater increase in cell area and cortical stiffness and decrease in NF-κB nuclear translocation in response to TNF-α treatment compared to controls than cells plated on 10 kPa substrates. The response of endothelial cells on soft substrates to shear stress depends on the presence of hyaluronan (HA). These results emphasize the importance of substrate stiffness on endothelial function, and elucidate a means by which vascular stiffening in aging and disease can impact the endothelium.

Synthesis and characterization of Pt nanoparticles with different morphologies in mesoporous silica SBA-15 for methanol oxidation reaction

Mesoporous SBA-15 silica materials functionalized with and without carboxylic acid groups were used to effectively control the morphology of Pt crystals, and the materials thus obtained were applied to methanol oxidation reactions. The Pt particles aggregated to form long spheroids inside the channels in pure SBA-15. When carboxylic acid groups were utilized, the SBA-15(-COOH) material facilitated the formation of higher Pt surface area, smaller Pt nanoparticles and nearly spherical shape due to the strong interaction between Pt(4+) ions and carboxylic acid on SBA-15. The Pt(4+) ions on the SBA-15(-COOH) material can be directly transformed to reduced Pt particles during calcination. The methanol oxidation activity on a Pt surface is strongly dependent on the shape of Pt particles. The near-spherical Pt nanoparticles on the SBA-15(-COOH) exhibited higher catalytic activity during methanol oxidation than Pt catalysts on unmodified SBA-15. The near-spherical Pt particles on the SBA-15(-COOH) contained large numbers of terrace sites on their surfaces, which led to high efficiency during methanol oxidation.

Laparoscopic intersphincteric resection for low rectal cancer: comparison of stapled and manual coloanal anastomosis

AIM

The study aim was to analyse the safety and feasibility of laparoscopic intersphincteric resection with stapled coloanal anastomosis for low rectal cancer.

METHOD

Between March 2009 and August 2010, 22 patients underwent laparoscopic intersphincteric resection with a stapled coloanal anastomosis without a diverting ileostomy. The results were compared retrospectively with hand-sewn coloanal anastomoses performed between January 2001 and May 2009, which included 55 open and 38 laparoscopic intersphincteric resections. The morbidity comparison only included data relevant to the anastomosis. Function was compared using the Saito function questionnaire and the Wexner score and only involved data relevant to the laparoscopy.

RESULTS

The anastomotic complication rates were similar for fistula, bleeding and neorectal mucosal prolapse (P = 0.526, P = 0.653 and P = 0.411, respectively). Anastomotic leakage and stricture formation of the stapled coloanal anastomosis were significantly lower than those of the hand-sewn coloanal anastomosis (P = 0.037 and P = 0.028, respectively). There were no significant differences in the Saito function questionnaire and the Wexner score between the stapled and hand-sewn coloanal anastomotic groups (all P > 0.05).

CONCLUSION

Laparoscopic intersphincteric resection with a stapled coloanal anastomosis is technically feasible and is less likely to result in anastomotic leakage and stricture formation than a hand-sewn anastomosis.

Sapphire-based graphene saturable absorber for long-time working femtosecond lasers

We report a long-time working femtosecond laser using metal-free sapphire-based graphene as a saturable absorber (SA). The sapphire-based graphene yielded excellent nonlinear saturable absorption properties and was demonstrated to be suitable as an SA for an ultrafast solid-state laser. Stable mode-locked pulses of 325 fs were obtained at a central wavelength of 1032 nm with a repetition rate of 66.3 MHz. At pump power of 8.23 W the average output power was 1.78 W and the highest pulse energy reached 26.8 nJ with a peak power of 72.6 kW. Our work opens up a facile route for making reliable graphene SA in the mode-locking technique and also displays an exciting prospect in making low-cost and ultrafast lasers.

Comparison of eight published static finite element models of the intact lumbar spine: predictive power of models improves when combined together

Finite element (FE) model studies have made important contributions to our understanding of functional biomechanics of the lumbar spine. However, if a model is used to answer clinical and biomechanical questions over a certain population, their inherently large inter-subject variability has to be considered. Current FE model studies, however, generally account only for a single distinct spinal geometry with one set of material properties. This raises questions concerning their predictive power, their range of results and on their agreement with in vitro and in vivo values. Eight well-established FE models of the lumbar spine (L1-5) of different research centers around the globe were subjected to pure and combined loading modes and compared to in vitro and in vivo measurements for intervertebral rotations, disc pressures and facet joint forces. Under pure moment loading, the predicted L1-5 rotations of almost all models fell within the reported in vitro ranges, and their median values differed on average by only 2° for flexion-extension, 1° for lateral bending and 5° for axial rotation. Predicted median facet joint forces and disc pressures were also in good agreement with published median in vitro values. However, the ranges of predictions were larger and exceeded those reported in vitro, especially for the facet joint forces. For all combined loading modes, except for flexion, predicted median segmental intervertebral rotations and disc pressures were in good agreement with measured in vivo values. In light of high inter-subject variability, the generalization of results of a single model to a population remains a concern. This study demonstrated that the pooled median of individual model results, similar to a probabilistic approach, can be used as an improved predictive tool in order to estimate the response of the lumbar spine.

The influence of matrix (an)isotropy on cardiomyocyte contraction in engineered cardiac microtissues

In the cardiac microenvironment, cardiomyocytes (CMs) are embedded in an aligned and structured extracellular matrix (ECM) to maintain the coordinated contractile function of the heart. The cardiac fibroblast (cFB) is the main cell type responsible for producing and remodeling this matrix. In cardiac diseases, however, adverse remodeling and CM death may lead to deterioration of the aligned myocardial structure. Here, we present an in vitro cardiac model system with uniaxial and biaxial constraints to induce (an)isotropy in 3D microtissues, thereby mimicking 'healthy' aligned and 'diseased' disorganized cardiac matrices. A mixture of neonatal mouse CMs and cFBs was resuspended in a collagen-matrigel hydrogel and seeded to form microtissues to recapitulate the in vivo cellular composition. Matrix disarray led to a stellate cell shape and a disorganized sarcomere organization, while CMs in aligned matrices were more elongated and had aligned sarcomeres. Although matrix disarray has no detrimental effect on the force generated by the CMs, it did have a negative effect on the homogeneity of contraction force distribution. Furthermore, proliferation of the cFBs affected microtissue contraction as indicated by the negative correlation between the percentage of cFBs in the microtissues and their beating frequency. These results suggest that in regeneration of the diseased heart, reorganization of the disorganized matrix will contribute to recover the coordinated contraction but restoring the ratio in cellular composition (CMs and cFBs) is also a prerequisite to completely regain tissue function.

Facile synthesis of graphene on dielectric surfaces using a two-temperature reactor CVD system

Direct deposition of graphene on a dielectric substrate is demonstrated using a chemical vapor deposition system with a two-temperature reactor. The two-temperature reactor is utilized to offer sufficient, well-proportioned floating Cu atoms and to provide a temperature gradient for facile synthesis of graphene on dielectric surfaces. The evaporated Cu atoms catalyze the reaction in the presented method. C atoms and Cu atoms respectively act as the nuclei for forming graphene film in the low-temperature zone and the zones close to the high-temperature zones. A uniform and high-quality graphene film is formed in an atmosphere of sufficient and well-proportioned floating Cu atoms. Raman spectroscopy, scanning electron microscopy and atomic force microscopy confirm the presence of uniform and high-quality graphene.

A review of central retinal artery occlusion: clinical presentation and management

Central retinal artery occlusion (CRAO) is an ophthalmic emergency and the ocular analogue of cerebral stroke. Best evidence reflects that over three-quarters of patients suffer profound acute visual loss with a visual acuity of 20/400 or worse. This results in a reduced functional capacity and quality of life. There is also an increased risk of subsequent cerebral stroke and ischaemic heart disease. There are no current guideline-endorsed therapies, although the use of tissue plasminogen activator (tPA) has been investigated in two randomized controlled trials. This review will describe the pathophysiology, epidemiology, and clinical features of CRAO, and discuss current and future treatments, including the use of tPA in further clinical trials.