Thermodynamic analysis of carbon migration in W1-1.0C steel in plasma surface chromizing

W 1-1.0C steel was chromized at 1173 K with double glow plasma surface alloying process, and the distribution of Fe, Cr, and C contents in the chromized layer was measured using glow discharge spectrum analysis （GDA）. The behavior and mechanism of carbon migration during the formation of chromized layer were studied through thermodynamic analysis and calculation. The gradient of carbon chemical potential was regarded as the driving force of carbon migration. An equation was derived to describe the carbon content varying with the chromium content within the carbon-rich region. The calculated results from the equation approximated closely to the experimental ones.

Rho/Rock signal transduction pathway is required for MSC tenogenic differentiation

Mesenchymal stem cell （MSC）-based treatments have shown promise for improving tendon healing and repair. MSCs have the potential to differentiate into multiple lineages in response to select chemical and physical stimuli, including into tenocytes. Cell elongation and cytoskeletal tension have been shown to be instrumental to the process of MSC differentiation. Previous studies have shown that inhibition of stress fiber formation leads MSCs to default toward an adipogenic lineage, which suggests that stress fibers are required for MSCs to sense the environmental factors that can induce differentiation into tenocytes. As the Rho/ROCK signal transduction pathway plays a critical role in both stress fiber formation and in cell sensation, we examined whether the activation of this pathway was required when inducing MSC tendon differentiation using rope-like silk scaffolds. To accomplish this, we employed a loss-of-function approach by knocking out ROCK, actin and myosin （two other components of the pathway） using the specific inhibitors Y-27632, Latrunculin A and blebbistatin, respectively. We demonstrated that independently disrupting the cytoskeleton and the Rho/ ROCK pathway abolished the expression of tendon differentiation markers and led to a loss of spindle morphology. Together, these studies suggest that the tension that is generated by MSC elongation is essential for MSC teno-differentiation and that the Rho/ROCK pathway is a critical mediator of tendon differentiation on rope-like silk scaffolds.

Processing stage-guided effects of spices on the formation and accumulation of heterocyclic amines in smoked and cooked sausages

Heterocyclic amines (HAs) could be generated though sausage processing.The results showed that garlic,black pepper,chili inhibited the formation of HAs (584.29 ng/g,613.11 ng/g,677.23 ng/g) whereas ginger and Sichuan pepper intensified (965.66 ng/g,916.59 ng/g) compare with control sausage 863.86 ng/g.Furthermore,the study showed that garlic,black pepper,chilli all inhibited the formation of total HAs at stage of raw,drying,baking and steaming and had different inhibitory effect at every stage.Black pepper had the best inhibitory effect across four stages and inhibition rate reached 65%,69%,66%,84% after each stage.Chilli was the only one had inhibitory effect on both free and protein-bound HAs at every stage and inhibition rate about free and protein-bound HAs reached 38% and 76% in finished sausage.Adding certain spices properly during processing would be helpful to obtain fewer HAs in sausage.

Multiplexed imaging of tumor immune microenvironmental markers in locally advanced or metastatic non-small-cell lung cancer characterizes the features of response to PD-1 blockade plus chemotherapy

Background:Although programmed cell death 1(PD-1)blockade plus chemotherapy can significantly prolong the progression-free survival(PFS)and overall survival(OS)in first-line settings in patients with driver-negative advanced non-small-cell lung cancer(NSCLC),the predictive biomarkers remain undetermined.Here,we investigated the predictive value of tumor immune microenvironmental marker expression to characterize the response features to PD-1 blockade plus chemotherapy.Methods:Tumor tissue samples at baseline were prospectively collected from 144 locally advanced or metastatic NSCLC patients without driver gene alterations who received camrelizumab plus chemotherapy or chemotherapy alone.Tumor immune microenvironmental markers,including PD-1 ligand(PDL1),CD8,CD68,CD4 and forkhead box P3,were assessed using multiplex immunofluorescence(mIF)assays.Kaplan-Meier curveswere used to determine treatment outcome differences according to their expression status.Mutational profiles were compared between tumors with distinct expression levels of these markers and their combinations.Results:Responders had significantly higher CD8/PD-L1(P=0.015)or CD68/PD-L1 co-expression levels(P=0.021)than non-responders in the camrelizumab plus chemotherapy group,while no difference was observed in the chemotherapy group.Patients with high CD8/PD-L1 or CD68/PD-L1 co-expression level was associated with significantly longer PFS(P=0.002,P=0.024;respectively)and OS(P=0.006,P=0.026;respectively)than those with low co-expression in camrelizumab plus chemotherapy group.When comparing survival in the camrelizumab plus chemotherapy with chemotherapy by CD8/PD-L1 co-expression stratification,significantly better PFS(P=0.003)and OS(P=0.032)were observed in high co-expression subgroups.The predictive value of CD8/PD-L1 and CD68/PD-L1 co-expression remained statistically significant for PFS and OS when adjusting clinicopathological features.Although the prevalence of TP53 or KRAS mutations was similar between patients with and without CD8/PD-L1 or CD68/PD-L1 co-expression,the positive groups had a significantly higher proportion of TP53/KRAS co-mutations than the negative groups(both 13.0%vs.0.0%,P=0.023).Notably,enriched PI3K(P=0.012)and cell cycle pathway(P=0.021)were found in the CD8/PD-L1 co-expression group.Conclusion:Tumor immune microenvironmental marker expression,especially CD8/PD-L1 or CD68/PD-L1 co-expression,was associated with the efficacy of PD-1 blockade plus chemotherapy as first-line treatment in patients with advanced NSCLC.

pH-controlled DNAzymes： Rational design and their applications in DNA-machinery devices

The availability and reliability of strategies for molecular biosensing over a finely adjustable dynamic range is essential to enhance the understanding and control of vital biological process. To expand the versatility and utility of nucleic acid- related enzymes, we demonstrated a rational approach to acquiring tunable, pH-dependent deoxyribozymes （DNAzymes） with catalytic activities and response sensitivities that can be tuned through a simple change in solution pH. To do this, we capitalized upon the pH dependence of Hoogsteen interactions and designed i-motif- and triplex-based DNAzymes that can be finely regulated with high precision over a physiologically relevant pH interval. The modified DNAzymes are dependent upon pH for efficient cleavage of substrates, and their catalytic performance can be tuned by regulating the sequence of inserted i-motif/triplex structures. The principle of tunable, pH-dependent DNAzymes provides the opportunity to engineer pH-controlled DNA-machinery devices with unprecedented sensitivity to pH changes. For example, we constructed a DNA-walker device, the stepping rate of which could be adjusted by simply modulating solution pH within an interval of 5.6 to 7.4, as well as a DNA tetrahedron that can be opened at pH 6.4 and kept closed at pH 7.4. The potential of this approach is not limited to serve as pH-dependent devices, but rather may be combined with other elements to expand their practical usefulness.

Effects of fatty acid chain length and degree of unsaturation on the surface activities of monoacyl trehaloses

The surface properties of monoacyl trehaloses with different acyl chains were investigated at 30℃,40℃,50℃,and 60℃.Monoacyl trehaloses were enzymatically synthesized and purified with silica gel column chromatography and semi-preparative high-performance liquid chromatography(HPLC),and the purity of products was identified by mass spectrometry(MS)and nuclear magnetic resonance(NMR).The surface tension of monoacyl trehalose in pure water was measured using Doüy ring method at different temperatures.The critical micelle concentrations(CMC),surface tension at the CMC,γCMC,and residual area per molecule,a,were estimated from the curves.The CMC value of unsaturated monoacyl trehalose was affected by both the degree of unsaturation and the acyl chain length,and the effect of chain length on the CMC value was much stronger than that of the unsaturation degree.However,there was no significant dependency of theγCMC value and a values on the chain length or the unsaturated degree.

运用高分辨SD-OCT探测视神经脊髓炎谱系疾病视网膜厚度变化

目的分析视神经脊髓炎谱系疾病（NMOSD）在超高分辨谱域光学相干断层成像（UHR-OCT）中视网膜神经纤维和轴突损伤、视网膜厚度的亚临床变化,以更好地监测疾病进展和治疗该疾病.方法：病例对照研究.利用UHR-OCT分析21 例NMOSD患者和20 例健康志愿者（健康对照组）的9 个区域视网膜结构厚度,并根据NMOSD患者是否伴有视神经炎又分为非视神经炎（NO-ON）组（13 眼）和视神经炎（ON）组（13 眼）.运用单因素方差分析比较各组之间视网膜厚度的差异.结果：ON组在总厚度上较健康对照组、NO-ON组薄,除中央区外,其余区域差异均有统计学意义（均P 〈 0.001）.NO-ON组视网膜总厚度较健康对照组视网膜薄,主要在鼻侧内环（P=0.011）、颞侧内环（P=0.003）以及上侧外环（P=0.019）、下侧外环（P=0.002）,差异均有统计学意义.ON组视网膜神经纤维层（RNFL）及神经节细胞层＋内丛状层（GCL＋IPL）厚度在各象限与健康对照组相比较薄（P 〈 0.001）,NO-ON组的RNFL厚度较健康对照组鼻侧内环（P=0.049）和颞侧（P 〈 0.001）薄.NO-ON组的GCL＋IPL较健康对照组上侧外环（P 〈 0.001）和下侧外环（P=0.002）薄.ON组内核层厚度较对照组上侧内环（P=0.001）、下侧内环（P=0.003）、颞侧外环（P=0.043）厚,而NO-ON组较对照组在上侧外环（P=0.015）、下侧外环（P=0.012）薄.NO-ON组的Henle纤维层＋外核层厚度较对照组比较在上侧内环（P=0.009）、上侧外环（P=0.018）、下侧内环（P=0.001）、下侧外环（P=0.001）有下降,ON组与对照组比较差异无统计学意义.结论：本研究发现NMOSD患者不同层次的视网膜结构存在改变,在视神经未受累眼视网膜RNFL和GCIPL存在厚度下降,提示NMOSD患者未受累眼存在潜在的视网膜神经结构损伤.

Bevacizumab biosimilar LY01008 compared with bevacizumab(Avastin)as first-line treatment for Chinese patients with unresectable,metastatic,or recurrent non-squamous non-small-cell lung cancer:A multicenter,randomized,double-blinded,phase Ⅲ trial

Background:Previous studies have demonstrated the preclinical pharmacological and toxicological consistency,and clinical pharmacokinetic equivalence of bevacizumab biosimilar LY01008 with reference bevacizumab(Avastin).This randomized controlled trial aimed to compare the efficacy and safety of LY01008 with Avastin in first-line treatment of Chinese patients with advanced or recurrent non-squamous non-small cell lung cancer(NSCLC).Methods:StageⅢB-ⅣNSCLC patients with evaluable lesions,good physical status,and adequate organ functions from 67 centers across China were randomized in a ratio of 1:1 to receive LY01008 or Avastin 15 mg/kg intravenously in combination with paclitaxel/carboplatin(combined treatment)for 4-6 cycles,followed by maintenance monotherapy with LY01008 until disease progression,intolerable toxicity,or death.The primary endpoint was objective response rate(ORR)in accordance with Response Evaluation Criteria in Solid Tumors(RECIST)version 1.1 confirmed by independent radiological review committees(IRRC).Secondary endpoints included disease control rate(DCR),duration of response(DoR),progression-free survival(PFS),overall survival(OS),and safety.This study was registered in Clinical Trials.gov(NCT03533127).Results:Between December 15^(th),2017,and May 15^(th),2019,a total of 649 patients were randomized to the LY01008(n=324)or Avastin(n=325)group.As of September 25th,2019 for primary endpoint analysis,589 patients received ORR evaluation,with a median number of combined treatment cycles of 5(range 1-6)andmedian duration of treatment of 3.0(range 0.0-5.1)months.ORRof responseevaluable patients in the LY01008 and Avastin groups were 48.5% and 53.0%,respectively.The stratified ORR ratio was 0.91(90%CI 0.80-1.04,within the prespecified equivalence margin of 0.75-1.33).Up to May 15^(th),2020,with a median follow-up of 13.6(range 0.8-28.4)months,no notable differences in DCR,median DoR,median PFS,median OS,and 1-year OS rate were observed between the LY01008 and Avastin groups.There were no clinically meaningful differences in safety and immunogenicity across treatment groups.Conclusions:LY01008 demonstrated similarity to Avastin in terms of efficacy and safety in Chinese patients with advanced or recurrent non-squamous NSCLC.LY01008 combined with paclitaxel/carboplatin is expected to become a new treatment option for unresectable,metastatic,LY01008 and Avastin groups.There were no clinically meaningful differences in safety and immunogenicity across treatment groups.Conclusions:LY01008 demonstrated similarity to Avastin in terms of efficacy and safety in Chinese patients with advanced or recurrent non-squamous NSCLC.LY01008 combined with paclitaxel/carboplatin is expected to become a new treatment option for unresectable,metastatic,or recurrent non-squamous NSCLC patients in the first-line setting.

Photostable lysosomal imaging of living cell with hyperspectral stimulated Raman scattering microscopy using a probe based on bisarylbutadiyne

We designed a lysosome-selective Raman probe by conjugating bisphenylbutadiyne with morpholine, a well-known lysosome targeting moiety. This probe, named Lyso-BADY, has a Raman peak 28 times more intense than that of 5-ethynyl-2'-deoxyuridine. Lysosome in living cells was successfully visualized by hyperspectral stimulated Raman scattering (SRS) microscopy with this extracellular probe. Further study showed that the Raman signal of Lyso-BADY remained steady and strong even after a prolonged irradiation time. The photo-stability feature of Lyso-BADY rendered molecules of the similar structure as potentially versatile probe for continuous imaging in the future.

Enantioselective Diels-Alder reactions with left-handed G-quadruplex DNA-based catalysts

Since the discovery of left-handed G-quadruplex(L-G4)structure formed by natural DNA,there has been a growing interest in its potential functions.This study utilised it to catalyse enantioselective Diels-Alder reactions,considering its different optical rotation compared to an ordinary G4.It was determined that when L-G4 was used with a combination of copper(Ⅱ)ions,there was a good enantioselectivity(-52%ee)without further addition of ligands.When further consideration was given by adding G4 ligands,G4 was further stabilised,even obtaining a better enantioselectivity(up to-80%ee).Moreover,when using ligands that have regulatory effects on G4,the ee value can be adjusted.In this work,a minimal left-handed G4 was reported.A follow-up study was also con ducted,which recovers that the minimal left-handed G4 remains its catalytic effect and enantioselectivity,but is not so effective as the former case.This indicates that a complete G4 structure is relatively conducive to chiral catalysis.

Systematic investigation of bioorthogonal cellular DNA metabolic labeling in a photo-controlled manner

Bioorthogonal cleavage and ligation reactions together form one more integrated system about the repertoire of bioorthogonal chemistry,capacitating an array of thrilling new biological applications.The bond-cleavage type and position of biomolecular remain a great challenge,which determines the metabolic pathway of the targets in living systems.Herein we designed two linkages of methylene and carbonyl group attached the N-3 position of the 5-ethynyl-2’-deoxyuridine(EdU)base or the oxygen atom at deoxyribose 3’position to a photocaging group,which would be cleaved by irradiation with 365 nm ultraviolet light.EdU derivatives linked by methylene at the N-3 position had better photodecage efficiency and stability in the absence of light.This paper provides a strategy for studying the nucleoside metabolic pathways in cells,which can easily and conveniently evaluate the effect of the position and type of the linkages.The developed strategy affords a reference for controlling spatial and temporal metabolism of small-molecule drugs,allowing direct manipulation of intact cells under physiological conditions.

A highly efficient fluorescence-based switch-on detection method of 5-formyluracil in DNA

The identification of hydroxylmethyl- and formylpyrimidines in genomic DNA was a landmark event in epigenetics. Numerous laboratories in related fields are investigating the biology of these and other nucleic acid modifications. However, limitations in the ability to detect and synthesize appropriate modifications are an impediment. Herein, we explored a remarkable development in the selective detection of 5-formyluracil in both single-stranded and double-stranded DNA under mild conditions. The ＂switch-on＂ specificity towards 5-formyluracil enabled a high signal-to-noise ratio in qualitatively and quantitatively detecting materials containing 5-formyluradl, which is not affected by the presence of abasic sites and 5-formylcytosine, the modified cytosine counterpart of 5-formyluracil. In summar~ the innoxiousness, convenience, and cost-effidency of the 5-formyluracil phosphoramidite synthetic routine would promote the understanding of the epi^enetic role of this natural thvmidine modification.

Measurement of fast neutrons with ^(238)U-coated fission chamber

Purpose Afission chamber with two layers of 238Ufissile materials has been developed for the measurements of fast neutrons.Methods The developed fission chamber has been tested by 60Co gamma source and 252Cf neutron source.Results The results have indicated that it is very easy to cut off the gamma rays from the neutrons by using a discriminator,when the fission chamber works in the pulse mode.The detector works well,even if the static air is used as the filling gas.Conclusion To discuss the application of the detector,Monte Carlo simulations have been performed by considering four 238U-coated fission chambers located outside the spallation target for the fast neutron measurement from spallation reaction.The simulation results have indicated that the detector can be used to measure the fast neutron flux and neutron flux ratio of four fission chambers.Furthermore,a 238U-coated fission chamber can be used within a reactor for longer time,in comparison with a 235U-coated fission chamber.

Metabolic Labeling and Imaging of Cellular RNA via Bioorthogonal Cyclopropene−Tetrazine Ligation

RNA labeling is vital for the study of an RNA structure,cellular distribution,localization,and metabolism.Herein,we report N6 cyclopropane-modified adenosine(cpA)as a new analog for metabolic RNA labeling.We successfully applied inverse electrondemand Diels–Alder(iEDDA)chemistry to label cellular RNA with cpA.This labeling technique is practical and provides a new platform to study RNA roles in cells in a metal-free manner.This simple and robust assay represents a significant advancement in the profiling methods of the nascent transcriptome using chemical approaches.