Clinical features of patients with coronavirus disease 2019 from a designated hospital in Beijing, China.

Clinical and laboratory data on patients with coronavirus disease 2019 (COVID-19) in Beijing, China, remain extremely limited. In this study, we summarized the clinical characteristics of patients with COVID-19 from a designated hospital in Beijing. In total, 55 patients with laboratory-confirmed SARS-CoV-2 infection in Beijing 302 Hospital were enrolled in this study. Demographic data, symptoms, comorbidities, laboratory values, treatments, and clinical outcomes were all collected and retrospectively analyzed. A total of 15 (27.3%) patients had severe symptoms, the mean age was 44.0 years (interquartile range [IQR], 34.0-56.0), and the median incubation period was 7.5 days (IQR, 5.0-11.8). A total of 26 (47.3%) patients had exposure history in Wuhan of less than 2 weeks, whereas 20 (36.4%) patients were associated with familial clusters. Also, eighteen (32.7%) patients had underlying comorbidities including hypertension. The most common symptom of illness was fever (45; 81.8%); 51 (92.7%) patients had abnormal findings on chest computed tomography. Laboratory findings showed that neutrophil count, percentage of lymphocyte, percentage of eosinophil, eosinophil count, erythrocyte sedimentation rate, albumin, and serum ferritin are potential risk factors for patients with a poor prognosis. A total of 26 patients (47.3%) were still hospitalized, whereas 29 (52.7%) patients had been discharged. Compared with patients in Wuhan, China, the symptoms of patients in Beijing are relatively mild. Older age, more comorbidities, and more abnormal prominent laboratory markers were associated with a severe condition. On the basis of antiviral drugs, it is observed that antibiotics treatment, appropriate dosage of corticosteroid, and gamma globulin therapy significantly improve patients' outcomes. Early identification and timely medical treatment are important to reduce the severity of patients with COVID-19.

Polysaccharide Structures in the Outer Mucilage of Arabidopsis Seeds Visualized by AFM.

Evidence is presented that the polysaccharide rhamnogalacturonan I (RGI) can be biosynthesized in remarkably organized branched configurations and surprisingly long versions and can self-assemble into a plethora of structures. AFM imaging has been applied to study the outer mucilage obtained from wild-type (WT) and mutant (bxl1-3 and cesa5-1) Arabidopsis thaliana seeds. For WT mucilage, ordered, multichain structures of the polysaccharide RGI were observed, with a helical twist visible in favorable circumstances. Molecular dynamics (MD) simulations demonstrated the stability of several possible multichain complexes and the possibility of twisted fibril formation. For bxl1-3 seeds, the imaged polymers clearly showed the presence of side chains. These were surprisingly regular and well organized with an average length of ∼100 nm and a spacing of ∼50 nm. The heights of the side chains imaged were suggestive of single polysaccharide chains, while the backbone was on average 4 times this height and showed regular height variations along its length consistent with models of multichain fibrils examined in MD. Finally, in mucilage extracts from cesa5-1 seeds, a minor population of chains in excess of 30 µm long was observed.

Assembly of Protein Stacks With in Situ Synthesized Nanoparticle Cargo.

The ability of proteins to form hierarchical structures through self-assembly provides an opportunity to synthesize and organize nanoparticles. Ordered nanoparticle assemblies are a subject of widespread interest due to the potential to harness their emergent functions. In this work, the toroidal-shaped form of the protein peroxiredoxin, which has a pore size of 7 nm, was used to organize iron oxyhydroxide nanoparticles. Iron in the form of Fe2+ was sequestered into the central cavity of the toroid ring using metal-binding sites engineered there and then hydrolyzed to form iron oxyhydroxide particles bound into the protein pore. By precise manipulation of the pH, the mineralized toroids were organized into stacks confining one-dimensional nanoparticle assemblies. We report the formation and the procedures leading to the formation of such nanostructures and their characterization by chromatography and microscopy. Electrostatic force microscopy clearly revealed the formation of iron-containing nanorods as a result of the self-assembly of the iron-loaded protein. This research bodes well for the use of peroxiredoxin as a template with which to form nanowires and structures for electronic and magnetic applications.

Piperine potentiates the effects of trans-resveratrol on stress-induced depressive-like behavior: involvement of monoaminergic system and cAMP-dependent pathway.

Stress can act as a precipitation factor in the onset of emotional disorders, particularly depression. Trans-resveratrol is a polyphenolic compound enriched in polygonum cuspidatum and has been found to exert antidepressant-like effects in our previous studies. In present study, we assessed the effects of trans-resveratrol used in combination with piperine, commonly known as a bioavailability enhancer, on chronic unpredictable mild stress-induced depressive-like behaviors and relevant molecular targets. Trans-resveratrol used alone reduced the immobility time of rats in the forced swimming test, with the maximal effects of trans-resveratrol around 60 % inhibition at the highest dose tested, 40 mg/kg. However, when a subthreshold dose of piperine, 2.5 mg/kg was used in combination with trans-resveratrol, the minimum effective dose of trans-resveratrol in reducing the immobility time was reduced to 20 mg/kg. Further evidence from neurochemical (monoamines in the frontal cortex and the hippocampus), biochemical (monoamine oxidase, MAO activities) and molecular biological (cAMP, PKA, CREB and BDNF) assays supported the findings in the behavioral studies. These results suggest that the co-treatment strategy with trans-resveratrol and piperine might be an alternative therapy that provides efficacious protection against chronic stress.

Association of birth weight with cancer risk: a dose-response meta-analysis and Mendelian randomization study.

BACKGROUND: Several articles have shown that birth weight is associated with the risk of many types of cancers. However, the results are inconsistent, and whether the relationship has a causal effect remains unknown. METHODS: We searched the PubMed and Embase libraries up to March 2021 and selected observational studies reporting the relationship between birth weight and adult-onset cancer risk. Dose-response meta-analysis and two-sample Mendelian randomization (MR) analysis were used to estimate the effect. RESULT: In our dose-response meta-analysis, six cancers from 46 studies were found to have significant associations with birth weight. (Ovarian cancer: RR: 1.21, 95% CI 1.01-1.44; breast cancer: RR: 1.12, 95% CI 1.08-1.16; colorectal cancer: RR: 1.20, 95% CI 1.01-1.43; endometrial cancer: RR: 0.85, 95% CI 0.78-0.93; prostate cancer: RR: 1.27, 95% CI 1.01-1.61; testicular cancer: RR: 1.21, 95% CI 1.03-1.43). As birth weight increased, the slope of the dose-response curve of breast cancer increased continuously, and the curve of testicular cancer was U-shaped. In the MR study, seven cancers were included. Only invasive mucinous ovarian cancer was found to have a causal effect on birth weight (OR: 0.62; 95% CI 0.39-0.97), while other cancers did not. CONCLUSIONS: Our findings suggest that birth weight are unlikely to have a casual effect on risk of cancers via the MR analysis, although the dose-response meta-analysis shows that there is a nonlinear relationship between birth weight and breast cancer and testicular cancer. More relevant researches are needed to further investigate their effect.

Atomic Force Microscopy of Proteins.

Atomic force microscopy (AFM) enables imaging of surface-deposited proteins and protein structures under physiological conditions, which is a benefit compared to ultra-high vacuum techniques such as electron microscopy. AFM also has the potential to provide more information from the phase in tapping mode or from functional AFM modes. The sample preparation, probe selection, and imaging conditions are crucial for successful imaging of proteins. Here we give a detailed account of the steps toward imaging of soft samples in both air and liquid along with the basic theory underpinning these details.

Hydration dependent mechanical performance of denture adhesive hydrogels.

OBJECTIVE: Hydration in denture adhesives regulates the formation of complex morphologies and mechanical function. Multiscale experimental approaches are required to evaluate the impact of hydration on the inherent heterogeneity of denture adhesive-based hydrogels at different length scales and the impact of such phenomena on adhesion performance. METHODS: The morphology of hydrated denture adhesives was examined via cryo-scanning electron microscopy (cryo-SEM). The rheological and thermodynamic behaviour of bulk hydrated deture adhesives was examined by rheology and differential scanning Calorimetry (DSC). The microscopic mechanical properties of the denture adhesives were characterised by atomic force microscopy (AFM) and compared to the properties measured at the macroscopic scale. RESULTS: The rheological and mechanical properties of commerically available denture adhesive hydrogels were found to be critically dependent on both the formulation of the adhesives and their hydration level. Clear progression of phase separation was observed in hydrated denture adhesives as hydration increased and changed the mechanical properties of the adhesives at multiple length scales. The adhesives displaying more heterogeneous structures, which were associated with the presence of hydrophobic and organic compounds in the formulation, exhibited more variable mechanical behaviour and weaker rheological properties, but stronger adhesive properties. SIGNIFICANCE: Our results are important in defining the relationships between hydrophilicity, hydration, mechanical and adhesive properties of denture adhesives, allowing the development of improved chemical formulations that control the fixation of dentures.

Hydrophobic and hydrophilic effects on water structuring and adhesion in denture adhesives.

Denture adhesives are designed to be moisture-sensitive through the inclusion of a blend of polymer salts with varying degrees of water-sensitivity. This enables the adhesive to mix with saliva in vivo and activate its high tack, through the formation of a mucilaginous layer. We report for the first time, the use of differential scanning calorimetry to study a series of hydrophobic and hydrophilic polymeric systems in order to correlate water-structuring behavior with adhesion strength. Adhesive bonding of the more hydrophobic variants was higher than that of a commercial-based control and a more hydrophilic polymer system in both lap shear and tensile configurations. Water-binding data suggested that increasing the hydrophobicity of the maleic acid copolymer substituents led to decreased levels of freezing water. In comparison, increasing the hydrophilic nature of the polymer backbone gave higher levels of freezing water within the hydrated samples. The results of this study emphasize the importance of varying the levels of hydrophobic and hydrophilic components within denture adhesive formulations, alongside the types of water present within the adhesive systems. This phenomenon has shown the potential to fine-tune the adhesive properties and failure mode against poly(methyl methacrylate), surfaces. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1355-1362, 2018.

Preparation of transition metal composite graphite felt cathode for efficient heterogeneous electro-Fenton process.

A composite graphite felt (GF) modified with transition metal was fabricated and used as cathode in heterogeneous electro-Fenton (EF) for methyl orange (MO) degradation. Characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), the morphology and surface physicochemical properties of the cathodes after modification were observed considerably changed. After loading metals, the current response became higher, the accumulation of H2O2 and the degradation efficiency of MO were improved. Under the same conditions, GF-Co had the highest catalytic activity for electro-reduction of O2 to H2O2 and MO degradation. At pH 3, 99 % of MO degradation efficiency was obtained using GF-Co after 120 min treatment and even at initial pH 9, 82 % of that was obtained. TOC removal efficiency reached 93.8 % using GF-Co at pH 3 after 120 min treatment while that was 12.3 % using GF. After ten-time runs, the mineralization ratio of the GF-Co was still 89.5 %, suggesting that GF-Co was very promising for wastewater treatment. The addition of isopropanol proved that ·OH played an important role in degradation of MO.

Micro-mechanical properties of the tendon-to-bone attachment.

The tendon-to-bone attachment (enthesis) is a complex hierarchical tissue that connects stiff bone to compliant tendon. The attachment site at the micrometer scale exhibits gradients in mineral content and collagen orientation, which likely act to minimize stress concentrations. The physiological micromechanics of the attachment thus define resultant performance, but difficulties in sample preparation and mechanical testing at this scale have restricted understanding of structure-mechanical function. Here, microscale beams from entheses of wild type mice and mice with mineral defects were prepared using cryo-focused ion beam milling and pulled to failure using a modified atomic force microscopy system. Micromechanical behavior of tendon-to-bone structures, including elastic modulus, strength, resilience, and toughness, were obtained. Results demonstrated considerably higher mechanical performance at the micrometer length scale compared to the millimeter tissue length scale, describing enthesis material properties without the influence of higher order structural effects such as defects. Micromechanical investigation revealed a decrease in strength in entheses with mineral defects. To further examine structure-mechanical function relationships, local deformation behavior along the tendon-to-bone attachment was determined using local image correlation. A high compliance zone near the mineralized gradient of the attachment was clearly identified and highlighted the lack of correlation between mineral distribution and strain on the low-mineral end of the attachment. This compliant region is proposed to act as an energy absorbing component, limiting catastrophic failure within the tendon-to-bone attachment through higher local deformation. This understanding of tendon-to-bone micromechanics demonstrates the critical role of micrometer scale features in the mechanics of the tissue. STATEMENT OF SIGNIFICANCE: The tendon-to-bone attachment (enthesis) is a complex hierarchical tissue with features at a numerous scales that dissipate stress concentrations between compliant tendon and stiff bone. At the micrometer scale, the enthesis exhibits gradients in collagen and mineral composition and organization. However, the physiological mechanics of the enthesis at this scale remained unknown due to difficulty in preparing and testing micrometer scale samples. This study is the first to measure the tensile mechanical properties of the enthesis at the micrometer scale. Results demonstrated considerably enhanced mechanical performance at the micrometer length scale compared to the millimeter tissue length scale and identified a high-compliance zone near the mineralized gradient of the attachment. This understanding of tendon-to-bone micromechanics demonstrates the critical role of micrometer scale features in the mechanics of the tissue.

Failure mechanisms in denture adhesives.

OBJECTIVE: The mechanical properties of bio adhesives in oral care application are expected to be critical in defining the stability and release of devices such as dentures from the oral tissue. A multiscale experimental mechanical approach is used to evaluate the performance of denture adhesive materials. METHODS: The inherent mechanical behavior of denture fixatives was examined by separating adhesive material from a representative polymethyl methacrylate (PMMA) surface using atomic force microscopy (AFM) approaches and compared to macroscopic mechanical testing. RESULTS: Failure of denture adhesive material was found to be critically dependent on the formation of fibrillar structures within the adhesive. Small scale mechanical testing provided evidence for the mechanical properties of the fibrillar structures formed within the adhesive in macroscopic mechanical testing and indicated the importance of the forces required to fail the adhesive at these small length scales in controlling both the maximum forces sustained by the bulk material as well as the ease of separating the adhesive from PMMA surfaces. SIGNIFICANCE: Our results are important in defining the performance of denture fixative materials and their control of adhesive behavior, allowing the potential to tune properties required in the adhesion and removal of dentures.

Numerical simulation of airflow fields in two typical nasal structures of empty nose syndrome: a computational fluid dynamics study.

BACKGROUND: The pathogenesis of empty nose syndrome (ENS) has not been elucidated so far. Though postulated, there remains a lack of experimental evidence about the roles of nasal aerodynamics on the development of ENS. OBJECTIVE: To investigate the nasal aerodynamic features of ENS andto explore the role of aerodynamic changes on the pathogenesis of ENS. METHODS: Seven sinonasal models were numerically constructed, based on the high resolution computed tomography images of seven healthy male adults. Bilateral radical inferior/middle turbinectomy were numerically performed to mimic the typical nasal structures of ENS-inferior turbinate (ENS-IT) and ENS-middle turbinate (ENS-MT). A steady laminar model was applied in calculation. Velocity, pressure, streamlines, air flux and wall shear stress were numerically investigated. Each parameter of normal structures was compared with those of the corresponding pathological models of ENS-IT and ENS-MT, respectively. RESULTS: ENS-MT: Streamlines, air flux distribution, and wall shear stress distribution were generally similar to those of the normal structures; nasal resistances decreased. Velocities decreased locally, while increased around the sphenopalatine ganglion by 0.20 ± 0.17 m/s and 0.22 ± 0.10 m/s during inspiration and expiration, respectively. ENS-IT: Streamlines were less organized with new vortexes shown near the bottom wall. The airflow rates passing through the nasal olfactory area decreased by 26.27% ± 8.68% and 13.18% ± 7.59% during inspiration and expiration, respectively. Wall shear stresses, nasal resistances and local velocities all decreased. CONCLUSION: Our CFD simulation study suggests that the changes in nasal aerodynamics may play an essential role in the pathogenesis of ENS. An increased velocity around the sphenopalatine ganglion in the ENS-MT models could be responsible for headache in patients with ENS-MT. However, these results need to be validated in further studies with a larger sample size and more complicated calculating models.

The antidepressant-like effect of fisetin involves the serotonergic and noradrenergic system.

Flavonoids, which are polyphenolic compounds, have been reported to possess remarkable antioxidant and anti-inflammatory activities. Among the dietary flavonoids, fisetin (3,3',4',7-tetrahydroxyflavone) possesses a significant spectrum of biochemical and pharmacological actions. The present study aimed to investigate the antidepressant potential of fisetin and its possible mechanism. Two mouse models of despair tests were used to evaluate the antidepressant-like effect of fisetin. The results suggested that fisetin (10 and 20mg/kg, p.o.) dose dependently inhibited the immobility time in both behavioral tests, while the doses that affected the immobile response did not affect locomotor activity. Two behavioral models, reserpine-induced hypothermia and ptosis, and p-chlorophenylalanine (PCPA)-induced depletion of serotonin, were used to explore the possible involvement of fisetin in the noradrenergic and serotonergic system. The higher dose of fisetin was found to effectively antagonize the hypothermia, but not ptosis, induced by reserpine. Pre-treatment with PCPA abolished the anti-immobility effect of fisetin in the forced swimming and tail suspension tests. Moreover, neurochemical assays showed that fisetin produced an increase in serotonin and noradrenaline levels in the frontal cortex and hippocampus. Monoamine oxidase (MAO) activity in the mouse brain was inhibited by 14.7% after treatment with fisetin, while MAO-B activity was not affected. These findings indicate that the antidepressant-like effect of fisetin involves the regulation of the central serotonin and noradrenaline levels.