Recent advances on enhancing 3D printing quality of protein-based inks: A review.

3D printing is an additive manufacturing technology that locates constructed models with computer-controlled printing equipment. To achieve high-quality printing, the requirements on rheological properties of raw materials are extremely restrictive. Given the special structure and high modifiability under external physicochemical factors, the rheological properties of proteins can be easily adjusted to suitable properties for 3D printing. Although protein has great potential as a printing material, there are many challenges in the actual printing process. This review summarizes the technical considerations for protein-based ink 3D printing. The physicochemical factors used to enhance the printing adaptability of protein inks are discussed. The post-processing methods for improving the quality of 3D structures are described, and the application and problems of fourth dimension (4D) printing are illustrated. The prospects of 3D printing in protein manufacturing are presented to support its application in food and cultured meat. The native structure and physicochemical factors of proteins are closely related to their rheological properties, which directly link with their adaptability for 3D printing. Printing parameters include extrusion pressure, printing speed, printing temperature, nozzle diameter, filling mode, and density, which significantly affect the precision and stability of the 3D structure. Post-processing can improve the stability and quality of 3D structures. 4D design can enrich the sensory quality of the structure. 3D-printed protein products can meet consumer needs for nutritional or cultured meat alternatives.

Regulation of beta-amyloid for the treatment of Alzheimer's disease: Research progress of therapeutic strategies and bioactive compounds.

Alzheimer's disease (AD) is a progressive neurodegenerative disease that is difficult to treat. Extracellular amyloid is the principal pathological criterion for the diagnosis of AD. Amyloid ß (Aß) interacts with various receptor molecules on the plasma membrane and mediates a series of signaling pathways that play a vital role in the occurrence and development of AD. Research on receptors that interact with Aß is currently ongoing. Overall, there are no effective medications to treat AD. In this review, we first discuss the importance of Aß in the pathogenesis of AD, then summarize the latest progress of Aß-related targets and compounds. Finally, we put forward the challenges and opportunities in the development of effective AD therapies.

Increasing rates of long-term nitrogen deposition consistently increased litter decomposition in a semi-arid grassland.

The continuing nitrogen (N) deposition observed worldwide alters ecosystem nutrient cycling and ecosystem functioning. Litter decomposition is a key process contributing to these changes, but the numerous mechanisms for altered decomposition remain poorly identified. We assessed these different mechanisms with a decomposition experiment using litter from four abundant species (Achnatherum sibiricum, Agropyron cristatum, Leymus chinensis and Stipa grandis) and litter mixtures representing treatment-specific community composition in a semi-arid grassland under long-term simulation of six different rates of N deposition. Decomposition increased consistently with increasing rates of N addition in all litter types. Higher soil manganese (Mn) availability, which apparently was a consequence of N addition-induced lower soil pH, was the most important factor for faster decomposition. Soil C : N ratios were lower with N addition that subsequently led to markedly higher bacterial to fungal ratios, which also stimulated litter decomposition. Several factors contributed jointly to higher rates of litter decomposition in response to N deposition. Shifts in plant species composition and litter quality played a minor role compared to N-driven reductions in soil pH and C : N, which increased soil Mn availability and altered microbial community structure. The soil-driven effect on decomposition reported here may have long-lasting impacts on nutrient cycling, soil organic matter dynamics and ecosystem functioning.

Factors related to mental health of inpatients with COVID-19 in Wuhan, China.

OBJECTIVE: To evaluate the mental health status of hospitalized patients with coronavirus disease 2019 (COVID-19) and to explore the related factors. METHOD: This was a cross-sectional survey among COVID-19 inpatients in two isolation wards of a designated hospital in Wuhan, China, from March 7, 2020, to March 24, 2020. Participants' demographic data, clinical data and levels of circulating inflammatory markers were collated. Mental health symptoms were evaluated with questionnaires, which included the Insomnia Severity Index (ISI) scale, the 9-item Patient Health Questionnaire (PHQ-9), the 7-item Generalized Anxiety Disorder (GAD-7) scale, and questions about patients' self-perceived illness severity. Multivariate linear regression analysis was performed to explore factors that associated with mental symptoms, and a structural equation model (SEM) was used to assess the possible relationships between those factors and the patients' mental health. RESULTS: Among the 85 participants, 45.9% had symptoms of depression (PHQ-9 ≥ 5), 38.8% had anxiety (GAD-7 ≥ 5), and 54.1% had insomnia (ISI ≥ 8). According to multivariate regression analysis, female sex, a higher level of interleukin (IL)-1ß and greater self-perceived illness severity were all significantly associated with a higher PHQ-9 score, higher GAD-7 score and higher ISI score. In addition, the disease duration and the neutrophil to lymphocyte ratio (NLR) were positively related to patients' self-perceived illness severity. The results of the SEM analyses suggested that sex (ß = 0.313, P < 0.001), self-perceived illness severity (ß = 0.411, P < 0.001) and levels of inflammatory markers (ß = 0.358, P = 0.002) had direct effects on patients' mental health. The disease duration (ß = 0.163, P = 0.003) and levels of inflammatory markers (ß = 0.101, P = 0.016) also indirectly affected patients' mental health, with self-perceived illness severity acting as a mediator. CONCLUSION: A majority of COVID-19 infected inpatients reported experiencing mental health disturbances. Female sex, disease duration, levels of inflammatory markers and self-perceived illness severity are factors that could be used to predict the severity of patients' mental symptoms.

The efficacy and safety of Batroxobin in combination with anticoagulation on cerebral venous sinus thrombosis.

Cerebral venous sinus thrombosis (CVST) is an uncommon subtype of stroke with highly variable clinical presentation. Although anticoagulation with heparin and/or warfarin remains the standard treatment for CVST, treatment failure is still common. This study aims to evaluate the safety and efficacy of Batroxobin in combination with anticoagulation on CVST control. In this retrospective study, a total of 61 CVST patients were enrolled and divided into Batroxobin (n = 23) and control (n = 38) groups. In addition to the same standard anticoagulation in control, patients in the treatment group received Batroxobin 5 BU intravenous infusion (10 BU for the first time) every other day, for a total of three infusions. A higher recanalization rate was found in Batroxobin group (adjusted OR [95% CI] of 2.5 [1.1-5.0], p = 0.028) compared to the control group, especially in patients with high levels of fibrinogen (adjusted OR [95% CI] of 4.7 [1.4-16.7], p = 0.015). Statistically significant differences between the two groups were seen regarding the levels of thrombin time, fibrinogen and D-dimer at each cut-off time point (all p < 0.01). Compared with baseline, NIHSS scores at discharge showed significant improvement in the Batroxobin group [0(0, 4.25)-5(2, 11), p = 0.036]. No significant difference in mRS scores was found between the two groups at discharge or at 6-month outpatient follow-up (all p > 0.05). Additionally, Batroxobin did not increase the risk of intracranial hemorrhage. We conclude that Batroxobin is a potentially safe and effective adjunct therapeutic agent promoting CVST recanalization especially in patients with high level of fibrinogen.

To Predict Visual Deterioration According to the Degree of Intracranial Hypertension in Patients with Cerebral Venous Sinus Thrombosis.

BACKGROUND: Visual damage is one of the most common complications of cerebral venous sinus thrombosis (CVST)-associated intracranial hypertension (IH). This study is aimed at stratifying the risk of IH-induced visual damage in an attempt to predict its deterioration and prevent high-risk patients from irreversible eyesight impairment promptly. METHODS: A total of 94 patients with confirmed diagnosis of CVST were eligible for enrollment in this study. According to cerebrospinal fluid pressure at admission, the involved patients were classified into mild IH (< 250 mmH2O), moderate IH (250-330 mmH2O), and severe IH (≥330 mmH2O) groups. RESULTS: The ratio of visual deterioration in the severe IH group was 75%, which was significantly higher than in either the moderate (44.4%) or the mild groups (14.3%). As regards subjects without visual symptoms at admission, visual deterioration occurred in 9.4 ± 4.5 days after admission in the severe group while it occurred in 30.5 ± 16.8 days in the moderate group (p = 0.024). The conditional inference tree and random forest revealed that severe IH might be considered as an index of visual deterioration. Visual field defect, fading eyesight, and papilledema were significantly worse in patients with severe IH as compared to patients with mild or moderate IH, all p < 0.01. CONCLUSIONS: IH ≥330 mmH2O may be a cut-off value to predict the deterioration of visual damage in CVST, revealing that ophthalmologic interventions should be considered in a timely manner in this condition, particularly when recanalization of cerebral venous sinus cannot be achieved within a short time.

Development and Characterization of High-Throughput EST-Based SSR Markers for Pogostemon cablin Using Transcriptome Sequencing.

Simple sequence repeats (SSRs) or microsatellite markers derived from expressed sequence tags (ESTs) are routinely used for molecular assisted-selection breeding, comparative genomic analysis, and genetic diversity studies. In this study, we investigated 54,546 ESTs for the identification and development of SSR markers in Pogostemon cablin (Patchouli). In total, 1219 SSRs were identified from 1144 SSR-containing ESTs. Trinucleotides (80.8%) were the most abundant SSRs, followed by di- (10.8%), mono- (7.1%), and hexa-nucleotides (1.3%). The top six motifs were CCG/CGG (15.3%), AAG/CTT (15.0%), ACC/GGT (13.5%), AGG/CCT (12.4%), ATC/ATG (9.9%), and AG/CT (9.8%). On the basis of these SSR-containing ESTs, a total of 192 primer pairs were randomly designed and used for polymorphism analysis in 38 accessions collected from different geographical regions of Guangdong, China. Of the SSR markers, 45 were polymorphic and had allele variations from two to four. Furthermore, a transferability analysis of these primer pairs revealed a 10⁻40% cross-species transferability in 10 related species. This report is the first comprehensive study on the development and analysis of a large set of SSR markers in P. cablin. These markers have the potential to be used in quantitative trait loci mapping, genetic diversity studies, and the fingerprinting of cultivars of P. cablin.

Fermentation-inspired macroporous and tough gelatin/sodium alginate hydrogel for accelerated infected wound healing.

Gelatin and sodium alginate (SA) are two important biological macromolecules, exhibiting excellent biocompatibility and gel-forming ability. However, traditional SA and gelatin hydrogel displays limited mass transport, low porosity, instability, and poor mechanical properties extremely restricted their therapeutic effect and application scenarios. Herein, microbial fermentation and synergistic toughening strategies were used for preparing macroporous and tough hydrogel. The study investigated the fermentation and toughening conditions of hydrogel. The hydrogel composed of CaCl2 cross-linked physically network and EDC/NHS cross-linked covalently network, exhibiting significantly improved mechanical properties, and excellent recovery efficiency. In addition, the hydrogel has a hierarchical macroporous structure of 100-500 µm, demonstrating high porosity of 10 times, swelling rate of 1541.0 %, and high mass infiltration capability. Further, after Ag+ treatment, the macroporous hydrogel dressing showed outstanding biocompatibility. Compared with non-porous hydrogel, the resulting macroporous hydrogel dressing displayed high antibacterial and antioxidant properties. It could effectively alleviate intracellular ROS formation induced by H2O2.In vivo experiments indicated that it has significantly better effect than non-porous hydrogel in accelerating wound healing. The overall results suggest that the gelatin/SA-based macroporous and tough hydrogel proposed in this study holds excellent prospects for application in wound dressings.

Polydopamine-assisted smart bacteria-responsive hydrogel: Switchable antimicrobial and antifouling capabilities for accelerated wound healing.

INTRODUCTION: Wound infections and formation of biofilms caused by multidrug-resistant bacteria have constituted a series of wound deteriorated and life-threatening problems. The in situ resisting bacterial adhesion, killing multidrug-resistance bacteria, and releasing dead bacteria is strongly required to supply a gap of existing sterilization strategies. OBJECTIVES: This study aims to present a facile approach to construct a bacteria-responsive hydrogel with switchable antimicrobial-antifouling properties through a "resisting-killing-releasing" method. METHODS: The smart bacteria-responsive hydrogel was constructed by two-step immersion strategy: a simple immersion-coating process to construct Polydopamine (pDA) coatings on the surface of a gelatin-chitosan composite hydrogel and followed by grafting of bactericidal quaternary ammonium chitosan (QCS) as well as pH-responsive PMAA to this pDA coating. The in vitro antimicrobial activity, biocompatibility and the in vivo wound healing effects in a mouse MRSA-infected full-thickness defect model of the hydrogel were further evaluated. RESULTS: Assisted by polydopamine coating, the pH-responsive PMAA and bactericidal QCS are successfully grafted onto a gelatin-chitosan composite hydrogel surface and hydrogels maintain the adequate mechanical properties. At physiological conditions, the PMAA hydration layer endows the hydrogel with resistance to initial bacterial attachment. Once bacteria colonize and acidize local environment, the swelling PMAA chains tend to collapse then expose the bactericidal QCS, realizing the on-demand kill bacteria. Moreover, the dead bacteria can be released and the hydrogel will resume the resistance due to hydrophilicity of PMAA at increased pH, endowing the surface renewable ability. In vitro and in vivo studies demonstrate the favorable biocompatibility and wound healing capacity of hydrogels that can inhibit infection and further facilitate granulation tissue, angiogenesis, and collagen synthesis. CONCLUSION: This strategy provides a novel methodology for the development and design of smart wound dressing to combat multidrug-resistant bacteria infections.

Greenhouse gas emissions from the growing season are regulated by precipitation events in conservation tillage farmland ecosystems of Northeast China.

Reducing greenhouse gas (GHG) emissions from agricultural ecosystems is vital to mitigate global warming. Conservation tillage is widely used in farmland management to improve soil quality; however, its effects on soil GHG emissions remain poorly understood, particularly in high-yield areas. Therefore, our study aimed to evaluate the effects of no-tillage (NT) combined with four straw-mulching levels (0 %, 33 %, 67 %, and 100 %) on GHG emission risk and the main influencing factors. We conducted in-situ observations of GHG emissions from soils under different management practices during the maize-growing season in Northeastern China. The results showed that NT0 (705.94 g m-2) reduced CO2 emissions by 18 % compared to ridge tillage (RT, 837.04 g m-2). Different straw mulching levels stimulated N2O emissions after rainfall, particularly under NT combined with 100 % straw mulching (2.89 kg ha-1), which was 45 % higher than that in any other treatments. The CH4 emissions flux among different treatments was nearly zero. Overall, straw mulching levels had no significant effect on the GHG emissions. During the growing season, soil NH4+-N (< 20 mg kg-1) remained low and decreased with the extension of growth stage, whereas soil NO3--N initially increased and then decreased. More importantly, the results of structural equation modeling indicate that: a) organic material input and soil moisture are key factors affecting CO2 emissions, b) nitrogen fertilizer and soil moisture promote N2O emissions, and c) climatic factors exert an inexorable influence on the GHG emissions process. Our conclusions emphasize the necessity of incorporating precipitation-response measures into farmland management to reduce the risk of GHG emissions.

Exopolysaccharides of Paenibacillus polymyxa: A review.

Paenibacillus polymyxa (P. polymyxa) is a member of the genus Paenibacillus, which is a rod-shaped, spore-forming gram-positive bacterium. P. polymyxa is a source of many metabolically active substances, including polypeptides, volatile organic compounds, phytohormone, hydrolytic enzymes, exopolysaccharide (EPS), etc. Due to the wide range of compounds that it produces, P. polymyxa has been extensively studied as a plant growth promoting bacterium which provides a direct benefit to plants through the improvement of N fixation from the atmosphere and enhancement of the solubilization of phosphorus and the uptake of iron in the soil, and phytohormones production. Among the metabolites from P. polymyxa, EPS exhibits many activities, for example, antioxidant, immunomodulating, anti-tumor and many others. EPS has various applications in food, agriculture, environmental protection. Particularly, in the field of sustainable agriculture, P. polymyxa EPS can be served as a biofilm to colonize microbes, and also can act as a nutrient sink on the roots of plants in the rhizosphere. Therefore, this paper would provide a comprehensive review of the advancements of diverse aspects of EPS from P. polymyxa, including the production, extraction, structure, biosynthesis, bioactivity and applications, etc. It would provide a direction for future research on P. polymyxa EPS.

Highly efficient conversion of mouse fibroblasts into functional hepatic cells under chemical induction.

Previous studies have shown that hepatocyte-like cells can be generated from fibroblasts using either lineage-specific transcription factors or chemical induction methods. However, these methods have their own deficiencies that restrict the therapeutic applications of such induced hepatocytes. In this study, we present a transgene-free, highly efficient chemical-induced direct reprogramming approach to generate hepatocyte-like cells from mouse embryonic fibroblasts (MEFs). Using a small molecule cocktail (SMC) as an inducer, MEFs can be directly reprogrammed into hepatocyte-like cells, bypassing pluripotent and immature hepatoblast intermediate stages. These chemical-induced hepatocyte-like cells (ciHeps) closely resemble mature primary hepatocytes in terms of morphology, biological behavior, gene expression patterns, marker expression levels, and hepatic functions. Furthermore, transplanted ciHeps can integrate into the liver, promote liver regeneration, and improve survival rates in mice with acute liver damage. ciHeps can also ameliorate liver fibrosis caused by chronic injuries and enhance liver function. Notably, ciHeps exhibit no tumorigenic potential either in vitro or in vivo. Mechanistically, SMC-induced mesenchymal-to-epithelial transition and suppression of SNAI1 contribute to the fate conversion of fibroblasts into ciHeps. These results indicate that this transgene-free, chemical-induced direct reprogramming technique has the potential to serve as a valuable means of producing alternative hepatocytes for both research and therapeutic purposes. Additionally, this method also sheds light on the direct reprogramming of other cell types under chemical induction.

Mechanisms of conservation tillage on nitrogen-fertilizer reduction and maize grain improvement in Mollisols of Northeast China: Insights from a 15N tracing study.

Conservation tillage is an important management practice to guarantee soil fertility in degraded Mollisols. It is still unclear, however, whether the improvement and stability of crop yield under conservation tillage can be sustainable with increasing soil fertility and reducing fertilizer-N application. Based on a long-term tillage experiment initiated in Lishu Conservation Tillage Research and Development Station by Chinese Academy of Sciences, we conducted a 15N tracing field micro-plot experiment to investigate the effects of reducing nitrogen application on maize yield and fertilizer-N transformation under long-term conservation tillage agroecosystem. There were four treatments, including conventional ridge tillage (RT), no-tillage with 0% (NT0), 100% (NTS) maize straw mul-ching, and 20% reduced fertilizer-N plus 100% maize stover mulching (RNTS). The results showed that after a complete cultivation round, the average percentages of fertilizer N recovery in soil residues, crop usage, and gaseous loss were 34%, 50%, and 16%, respectively. Compared with conventional ridge tillage, no-tillage with maize straw mulching (NTS and RNTS) significantly increased the use efficiency of fertilizer N in current season by 10% to 14%. From the perspective of N sourcing analysis, the average percentage of fertilizer N absorbed by crop parts (including seeds, straws, roots, and cobs) to the total N uptake reached nearly 40%, indicating that soil N pool was the main source of N for crop uptakes. In comparison with conventional ridge tillage, conservation tillage significantly increased total N storage in 0-40 cm by reducing soil disturbance and increasing organic inputs, and thus ensured the expansion and efficiency increment of soil N pool in degraded Mollisols. Compared with conventional ridge tillage, NTS and RNTS treatments significantly increased the maize yield from 2016 to 2018. In all, by improving fertilizer nitrogen utilization efficiency and maintaining the continuous supply of soil nitrogen, long-term management of no-tillage with maize straw mulching could achieve a stable and increasing maize yield in three consecutive growing seasons and simultaneously reduce environmental risks derived by fertilizer-N losses, even under the condition of 20% reduction of fertilizer-N application, and thus actualize the sustainable development of agriculture in Mollisols of Northeast China.

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Potassium (K) is the second most abundant nutrient in plant leaves after nitrogen (N) and the most abundant cation in plant cells. It plays an important role in plant growth regulation, homeostasis maintenance, and stress response. Previous studies on the effects of N input on plant nutrient status mainly focus on N and phosphorus (P), but less on K and its stoichiometry. We examined the effects of N input and mowing on K content and N:K at both plant functional group and community levels. We analyzed the relative contribution of changes in functional groups and community composition to changes of community level nutrition status. The results showed that N input increased N content of each plant functional group and increased K content of rhizomatous grasses and legumes. Mowing reduced N content of rhizomatous grasses and bunchgrass, but did not affect K content and N:K of all functional groups. Nitrogen input significantly increased plant N and K contents at the community level, while mowing significantly increased plant N content. Both N input and mowing did not affect plant N:K at functional group and community levels. The contribution of nutritional changes in plant functional groups to the variation at the community level was greater than that of changes in community composition. For all the three examined nutritional traits, the contribution of nutrients at functional group level and that of community composition showed negative covariation. Our results indicated that plant N:K had high homeostasis in meadow steppe and that plants could regulate N and K balance, which was of great significance for maintaining N:K stoichiometry under the background of increasing N deposition.

Therapeutic strategies of glioblastoma (GBM): The current advances in the molecular targets and bioactive small molecule compounds.

Glioblastoma (GBM) is the most common aggressive malignant tumor in brain neuroepithelial tumors and remains incurable. A variety of treatment options are currently being explored to improve patient survival, including small molecule inhibitors, viral therapies, cancer vaccines, and monoclonal antibodies. Among them, the unique advantages of small molecule inhibitors have made them a focus of attention in the drug discovery of glioblastoma. Currently, the most used chemotherapeutic agents are small molecule inhibitors that target key dysregulated signaling pathways in glioblastoma, including receptor tyrosine kinase, PI3K/AKT/mTOR pathway, DNA damage response, TP53 and cell cycle inhibitors. This review analyzes the therapeutic benefit and clinical development of novel small molecule inhibitors discovered as promising anti-glioblastoma agents by the related targets of these major pathways. Meanwhile, the recent advances in temozolomide resistance and drug combination are also reviewed. In the last part, due to the constant clinical failure of targeted therapies, this paper reviewed the research progress of other therapeutic methods for glioblastoma, to provide patients and readers with a more comprehensive understanding of the treatment landscape of glioblastoma.

The Role of Leukocyte Immunoglobulin-Like Receptors Focusing on the Therapeutic Implications of the Subfamily B2.

The leukocyte immunoglobulin (Ig)-like receptors (LILRs) are constituted by five inhibitory subpopulations (LILRB1-5) and six stimulatory subpopulations (LILRA1-6). The LILR populations substantially reside in immune cells, especially myeloid cells, functioning as a regulator in immunosuppressive and immunostimulatory responses, during which the nonclassical major histocompatibility complex (MHC) class I molecules are widely involved. In addition, LILRs are also distributed in certain tumor cells, implicated in the malignancy progression. Collectively, the suppressive Ig-like LILRB2 is relatively well-studied to date. Herein, we summarized the whole family of LILRs and their biologic function in various diseases upon ligation to the critical ligands, therefore providing more information on their potential roles in these pathological processes and giving the clinical significance of strategies targeting LILRs.

Small Molecule-Induced Differentiation As a Potential Therapy for Liver Cancer.

Despite the efficacy demonstrated by immunotherapy recently, liver cancer still remains one of the deadliest cancers, mainly due to heterogeneity of this disease. Continuous exploration of new therapeutics is therefore necessary. Chemical-induced cell differentiation can serve as a promising approach, with its ability to consistently remodel gene expression profile and alter cell fate. Inspired by advances in stem cell and reprogramming field, here it is reported that a small molecule cocktail (SMC) consisted of: SB431542 (TGFß inhibitor), CHIR99021 (GSK3ß inhibitor), BIX01294 (H3K9 methyltransferase/G9a inhibitor), and all-trans retinoic acid (ATRA), can induce differentiation of liver cancer cells including cell lines, primary cancer cells, cancer stem cells, and drug resistant cells. Treated cells lose malignant characteristics and regain hepatocyte phenotype instead. When applied in vivo, SMC induces wide range of tissue necrosis or fibrosis within the tumors, while remaining tissues begin to express hepatic nuclear factor 4α (HNF4α), the hepatic nuclear marker. SMC also leads to tumor abrogation in orthotopic xenograft models and life span extension of animals. The powerful differentiation induction of SMC is exerted through modulation of Akt/mTOR/HIF1α signaling and metabolic reprogramming, as well as suppressing Snail and enhancing HNF4α expression. Together, these results highlight that chemical-induced differentiation has the potential to effectively treat liver cancer disregard of heterogeneity.

Sleep disorders and related factors among frontline medical staff supporting Wuhan during the COVID-19 outbreak.

Sleep problems among frontline medical staff during the COVID-19 epidemic require attention. A total of 249 frontline medical staff who were recruited to support Wuhan completed this cross-sectional study. A web-based questionnaire about insomnia, depression, anxiety, and fatigue was used to assess mental health status. The prevalence of sleep disorders among frontline medical staff was 50.6%. More time spent in Wuhan and a history of insomnia, depression, anxiety, and fatigue were associated with a higher risk of insomnia. People who stayed in Wuhan for a long time with a history of insomnia, depression, anxiety, and fatigue symptoms might be at high risk of insomnia.

Sleep disorders and related factors among frontline medical staff supporting Wuhan during the COVID-19 outbreak.

Sleep problems among frontline medical staff during the COVID-19 epidemic require attention. A total of 249 frontline medical staff who were recruited to support Wuhan completed this cross-sectional study. A web-based questionnaire about insomnia, depression, anxiety, and fatigue was used to assess mental health status. The prevalence of sleep disorders among frontline medical staff was 50.6%. More time spent in Wuhan and a history of insomnia, depression, anxiety, and fatigue were associated with a higher risk of insomnia. People who stayed in Wuhan for a long time with a history of insomnia, depression, anxiety, and fatigue symptoms might be at high risk of insomnia.

Physicochemical characteristics of chitosan from swimming crab (Portunus trituberculatus) shells prepared by subcritical water pretreatment.

The physicochemical properties of chitosan obtained from the shells of swimming crab (Portunus trituberculatus) and prepared via subcritical water pretreatment were examined. At the deacetylation temperature of 90 °C, the yield, ash content, and molecular weight of chitosan in the shells prepared via subcritical water pretreatment were 12.2%, 0.6%, and 1187.2 kDa, respectively. These values were lower than those of shells prepared via sodium hydroxide pretreatment. At the deacetylation temperature of 120 °C, a similar trend was observed in chitosan molecular weight, but differences in chitosan yield and ash content were not remarkable. At the same deacetylation temperature, the structures of chitosan prepared via sodium hydroxide and subcritical water pretreatments were not substantially different. However, the compactness and thermal stability of chitosan prepared via sodium hydroxide pretreatment was lower than those of chitosan prepared via subcritical water pretreatment. Compared with the chitosan prepared by sodium hydroxide pretreatment, the chitosan prepared by subcritical water pretreatment was easier to use in preparing oligosaccharides, including (GlcN)2, via enzymatic hydrolysis with chitosanase. Results suggested that subcritical water pretreatment can be potentially used for the pretreatment of crustacean shells. The residues obtained via this method can be utilized to prepare chitosan.