Cytocompatibility with osteogenic cells and enhanced in vivo anti-infection potential of quaternized chitosan-loaded titania nanotubes

Infection is one of the major causes of failure of orthopedic implants. Our previous study demonstrated that nanotube modification of the implant surface, together with nanotubes loaded with quaternized chitosan （hydroxypropyltrimethyl ammonium chloride chitosan, HACC）, could effectively inhibit bacterial adherence and biofilm formation in vitro. Therefore, the aim of this study was to further investigate the in vitro cytocompatibility with osteogenic cells and the in vivo anti-infection activity of titanium implants with HACC-loaded nanotubes （NT-H）. The titanium implant （Ti）, nanotubes without polymer loading （NT）, and nanotubes loaded with chitosan （NT-C） were fabricated and served as controls. Firstly, we evaluated the cytocompatibility of these specimens with human bone marrow-derived mesenchymal stem cells in vitro. The observation of cell attachment, proliferation, spreading, and viability in vitro showed that NT-H has improved osteogenic activity compared with Ti and NT-C. A prophylaxis rat model with implantation in the femoral medullary cavity and inoculation with methiciUin-resistant Staphylococcus aureus was established and evaluated by radiographical, microbiological, and histopathological assessments. Our in vivo study demonstrated that NT-H coatings exhibited significant anti-infection capability compared with the Ti and NT-C groups. In conclusion, HACC-loaded nanotubes fabricated on a titanium substrate show good compatibility with osteogenic cells and enhanced anti-infection ability in vivo, providing a good foundation for clinical application to combat orthopedic implant-associated infections.

Effect of organic fertilizers used in sandy soil on the growth of tomatoes

In order to reveal the regulating capacity of organic fertilizers on sandy soil, pots experiments were carried out. The growth of tomatoes planted on sandy soil amended by organic fertilizers was measured. Organic fertilizers can be helpful to improve the plant height, stem diameter, the aerial parts fresh weight, root fresh weight, leaf photosynthetic rates and photosynthesis, and lay a good foundation for the growth of ??tomatoes. The effect of organic fertilizer is the most significant. Among all the treatments of adding 2.5%, 5%, 10% organic fertilizers, adding 10% organic fertilizers are the best. It can significantly enhance the growth and photosynthesis of tomatoes, and it is among the best of these three soil treatments for sandy soil.

Determination of Residual Amount of 15 Plant Growth Regulators in Bean Sprouts by HPLC-MS/MS

[Objectives]This study was conducted to effectively monitor PGR residues in bean sprouts to provide guarantee for the food safety of agricultural products.[Methods]A high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method for the determination of residues of 15 plant growth regulators(PGRs)in bean sprouts was established using bean sprouts as an experimental material.Samples were extracted with a solution containing 5%acetic acid-acetonitrile(1∶99,V/V),purified with anhydrous magnesium sulfate,and diluted with methanol solvent to constant volume.The solutions were filtered through 0.22μm filtering membrane and the target analytes were separated on a Phenomenex H18 column.The identification of each compound was established by retention time matching along with the accurate mass measurement of the precursor ions and their main fragment ions.The quantification was carried out using matrix-matched external standard method.[Results]The retention time of the 15 PGRs were found in the range from 5.8-11.7 min under the optimized conditions.The linear relation was good in the concentration range of 0.005-0.050μg/ml,and the correlation coefficients of the 15 PGRs were≥0.9990.The limits of detection were in the range of 0.03-0.92 g/kg,and the limits of quantification were in the range of 0.50-2.10μg/kg.The average recovery in the recovery test at 3 concentration levels was 80%-110%,and the relative standard deviations were in the range of 2.8%-7.5%.[Conclusions]This method is simple and accurate,and can quickly qualitatively and quantitatively analyze the residues of 15 PGRs in bean sprouts.The proposed procedure was simple,quick and accurate for the simultaneous determination of the 15 PGRs in bean sprout.

Irisin Attenuates Osteoarthritis by Inhibiting Apoptosis of Osteocytes Through Activating Erk Signaling Pathway

Osteoarthritis(OA)is an inflammatory disease involving the joints that is prevalent in the global aging population.The purpose of this study is to determine whether irisin can attenuate osteoarthritis(OA)progression in anterior cruciate ligament transection(ACLT)mice models and the mechanism of irisin therapy effect on OA by increase the resistance of apoptosis in MLO-Y4 cells induced by mechanical stretch in vitro.Methods For in vivo study,3-month-old male C57BL/6 J mice were randomized to three groups,sham-operated,anterior cruciate ligament transection(ACLT)-operated treated with vehicle,and ACLT-operated treated with irisin by intraperitoneal injection once a week.Cartilage erosion was observed by HE staining.Osteoarthritis Research Society International(OARSI)scores were evaluated according to the safranin O stai-ning.The microstructure of tibia cortical bone,trabecular bone,and subchondral bone was analyzed by micro-CT and the bone histomorphometry has been administrated including mineral apposition rate(MAR).Edu staining and cck-8 were used for the detection of the proliferation of MLO-Y4 cells.For mechanical stress,cells were seeded on the collagen-I coated chamber subjected with a peak biaxial stretch of 20%at 1 Hz for 16 hours to induce apoptosis.Flow cytometry was used for the detection of apoptosis and cell cycle.TUNNEL was used for staining the apoptotic cells and rt-PCR was applied for quantifying the expression of mRNA such as Bax,Bcl-2,SOST,c-myc,Opg.Western blot was utilized to confirm the mechanism of how irisin decrease the osteocyte apoptosis.Results In vivo,irisin can attenuate articular cartilage degeneration.Irisin maintains the proportion of hyaline cartilage and calcified cartilage and keep fewer cartilage erosions in ACLT-operated mice.For immunohistochemical(IHC)staining,irisin reduced the expression of caspase3,Bax and matrix metalloproteinase-13 in both cartilage and subchondral bone.Irisin-treated ACLT group shows higher Trabecular number(Tb.N)and bone volume fraction(BV/TV)compared to the vehicle-treated ACLT group.In vitro, irisin significantly increased the proliferation of MLO-Y4 cells detected by Edu and Ki67 staining,and irisin can protect the cells from both mechanical stretchinduced apoptosis detected by FITC-PI flow cytometry and maintain the cell activity by regulating the expression of Bax,Bcl-2,and c-myc.Transcriptome sequencing shows that irisin significantly activates the MAPK signaling pathway and we confirm the result by western blot:irisin effectively activates the Erk signaling pathway through phosphorylation and has a certain activation effect on p38 signaling pathway,no activation was observed for FAK signaling pathway.Conclusions Irisin can attenuate the progression of OA by decrease the apoptosis of osteocyte,which can improve the microarchitecture of subchondral bone.Erk pathway activation plays an important role in reducing the apoptosis of osteocyte.

Identification of Common Maize Diseases and Their Prevention and Control Methods

Agriculture is the basic industry of China's economic development,and maize is an important part of the agricultural economy.With the increase of global environmental warming and industrial pollution,as well as the adjustment of agricultural planting structure and the transformation of farming and cultivation methods in China,the breeding of maize varieties has been accelerated,and the planting area has increased rapidly,resulting in the condition that the occurrence of maize diseases and pests has been increasing.The damage of some minor diseases continued to increase nationwide or in local areas,and rose to major diseases,and some new diseases appeared in production,posing a threat to the safe production of maize.This paper summarized the occurrence status of important maize diseases in China,and put forward corresponding prevention and control countermeasures.

Methods for extraction of microorganism DNA from glacier surface snow

In order to thoroughly investigate the diversity of glacier microorganisms, four DNA extraction methods with differem lysis pat- terns were tested and two screened methods （the Bosshard-Bano method and the Zhou method） were optimized for the most ef- fective form of the filter membrane （cut vs. uncut）, the DNA extraction method, and the precipitation method. The two optimized methods were then compared with the commercial Mo-Bio DNA extraction kit, and the results showed that the kit was generally suitable for extraction of microorganism DNA fi＇om glacier surface snow. Procedurally, it was found that a modified Boss- hard-Bano method （i.e., cutting the filter membrane into pieces, using a specific lysis pattern [lysozyme （5 mg/mL）-protease K （ 1 mg/mL）-CTAB （ 1%）-SDS （ 1%）], performing the extraction only once by chloroform-isoamyl alcohol （24： 1）, and conducting DNA precipitation by pure ethanol） was also an effective and less expensive method for extraction of microorganism DNA from glacier surface snow.

基于决策树法构建创伤性颅脑损伤术后硬脑膜下积液的风险预测模型

目的:探讨创伤性颅脑损伤(TBI)术后硬脑膜下积液(PTSH)的影响因素,并构建TBI术后PTSH的决策树风险预测模型。方法:选取成都市郫都区人民医院重症医学科自2019年6月至2022年6月收治的344例TBI患者作为研究对象,根据是否发生PTSH将其分为观察组和对照组,分析2组患者的临床资料,采用单因素和Logistic回归分析筛选TBI患者发生PTSH的影响因素,采用SPSS Modeler软件构建TBI术后PTSH的决策树预测模型,并分析决策树预测模型的诊断效能。结果:344例TBI患者行DC后发生PTSH者68例,发生率为19.77%;单因素和多因素Logistic回归分析结果显示,蛛网膜撕裂、入院GCS评分>8分、中线移位、大骨瓣、骨窗面积>150 cm2、骨瓣边缘距中线距离>2 cm是TBI患者行DC后发生PTSH的影响因素(P<0.05);决策树模型选出了蛛网膜撕裂、入院GCS评分>8分、中线移位、大骨瓣、骨窗面积>150 cm^(2)、骨瓣边缘距中线距离>2 cm等6个解释变量作为模型的节点,其中蛛网膜撕裂是最重要的预测因子。ROC曲线分析显示,决策树模型的曲线下面积(AUC)值为0.895,Logistic回归模型的AUC值为0.881,决策树模型的预测效能优于Logistic回归模型(Z=2.423,P=0.013)。结论:蛛网膜撕裂、入院GCS评分>8分、中线移位、大骨瓣、骨窗面积>150 cm^(2)、骨瓣边缘距中线距离>2 cm是TBI患者行DC后发生PTSH的影响因素,构建的决策树模型有助于筛查DC后发生PTSH高风险人群和指导临床制定科学的防治策略,具有较高的临床价值。

Multiscale carbon foam confining single iron atoms for efficient electrocatalytic CO2 reduction to CO

Electrocatalytic CO2 reduction to CO is a sustainable process for energy conversion.However,this process is still hindered by the diffusi limited mass transfer,low electrical conductivity and catalytic activity.Therefore,new strategies for catalyst design should be adopted to solve these problems and improve the electrocatalytic performa nee for CO production.Herein,we report a multiscale carb on foam confining〔single iron atoms prepared with the assistant of S1O2 template.The pore-enriched environment at the macro-scale facilitates the diffusion of reacta nts and products.The graphe ne nano sheets at the nano-scale promote the charge tran sfer duri ng the reaction.The single iron atoms con fined in carb on matrix at the atomic-scale provide the active sites for electrocatalytic CO2 reductio n to CO.The optimized catalyst achieves a CO Faradaic efficiency of 94.9%at a moderate potential of-0.5 V vs.RHE.Furthermore,the performance can be maintained over 60 hours due to the stable single iron atoms coordi nated with four n itroge n atoms in the carb on matrix.This work provides a promising strategy to improve both the activity and stability of single atom catalysts for electrocatalytic CO2 reduction to CO.

Abundance and community of snow bacteria from three glaciers in the Tibetan Plateau

Bacterial abundance and diversity in snow of East Rongbuk, Laohugou and Halluogou glaciers on the Tibetan Plateau were investigated through epifluorescence microscope and denaturing gradient gel electrophoresis. Cell abundance ranged from 4.0 × 10^3 to 290.2 × 10^3 cells/mL. The phylogenetic trees placed the 16S rRNA sequences in four major groups： Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. Brevundimonas, Flavobacterium, Hymenobacter, Bacillus, Polaromonas, Rhodoferax and Streptomyces were widely distributed bacteria in glaciers from different cold regions. The remaining five genera of Hylemonella, Delftia, Zoogloea, Blastococcus and Rhodococcus were endemism, only recovered from our investigated glaciers. It is proposed that the three glaciers on the Tibetan Plateau provide a specific ecological niche for prolonging survival of diverse microbial lineages.

Y27632对急性视网膜缺血再灌注大鼠视网膜组织形态学的影响

目的:研究Rho激酶抑制剂Y27632对视网膜缺血再灌注损伤大鼠视网膜组织形态学的影响。方法:实验研究。将60只SD大鼠随机分为4组,每组15只:正常对照组(正常组)、急性缺血再灌注损伤组(IRI组)、0.9%氯化钠溶液对照组(生理盐水组)、Y27632治疗组(Y27632组)。再灌注损伤后24h(10只)和168h(5只)处死各组动物,行HE染色、ADP酶染色检查,光镜下观察大鼠视网膜组织病理学变化及视网膜厚度变化。数据采用单因素方差分析。结果:正常组大鼠视网膜结构清晰,三层细胞结构排列整齐。IRI组于再灌注24h后视网膜厚度增加,内外丛状层组织疏松,视网膜节细胞、内外核层细胞水肿明显、排列紊乱,视网膜节细胞减少。168h后,视网膜水肿消退、厚度变薄、呈萎缩状,神经节细胞及内外核层细胞数量减少,在视网膜前和神经纤维层可见毛细血管。再灌注24h后,IRI组视网膜厚度较正常组增加(P=0.005),Y27632组视网膜厚度低于生理盐水组(P=0.032)。再灌注168h后,IRI组视网膜厚度低于正常组(P<0.001),Y27632组视网膜厚度较生理盐水组增加(P=0.025)。正常组大鼠视网膜血管自视乳头发出,向四周呈放射状均匀分布,毛细血管网结构清晰。再灌注24h后,IRI组视网膜血管管径变细,走行较僵直,分支减少,视乳头周围及中周部视网膜可见大片无灌注区,无灌注区周围可见新生血管芽渐成网状。Y27632组可见视乳头周围及中周部视网膜局部无灌注区形成,无灌注区周围可见新生血管。后极部4PD无灌注区面积明显小于IRI组及生理盐水组。结论:Y27632玻璃体腔注射可以减轻视网膜缺血再灌注早期的视网膜水肿,减少视网膜神经节细胞的凋亡,减少视网膜新生血管生成,减轻再灌注晚期的视网膜萎缩,具有视神经保护作用。

Multi-omics analysis based on 3D-bioprinted models innovates therapeutic target discovery of osteosarcoma

Current in vitro models for osteosarcoma investigation and drug screening,including two-dimensional(2D)cell culture and tumour spheroids(i.e.cancer stem-like cells),lack extracellular matrix(ECM).Therefore,results from traditional models may not reflect real pathological processes in genuine osteosarcoma histological structures.Here,we report a three-dimensional(3D)bioprinted osteosarcoma model(3DBPO)that contains osteosarcoma cells and shrouding ECM analogue in a 3D frame.Photo-crosslinkable bioinks composed of gelatine methacrylamide and hyaluronic acid methacrylate mimicked tumour ECM.We performed multi-omics analysis,including transcriptomics and DNA methylomics,to determine differences between the 3DBPO model and traditional models.Compared with 2D models and tumour spheroids,our 3DBPO model showed significant changes in cell cycle,metabolism,adherens junctions,and other pathways associated with epigenetic regulation.The 3DBPO model was more sensitive to therapies targeted to the autophagy pathway.We showed that simulating ECM yielded different osteosarcoma cell metabolic characteristics and drug sensitivity in the 3DBPO model compared with classical models.We suggest 3D printed osteosarcoma models can be used in osteosarcoma fundamental and translational research,which may contribute to novel therapeutic strategy discovery.

Insight into the molecular mechanisms of gastric cancer stem cell in drug resistance of gastric cancer

Gastric cancer(GC)is one of the most common causes of cancer-related death worldwide,and gastric cancer stem cells(GCSCs)are considered as the major factor for resistance to conventional radio-and chemotherapy.Accumulating evidence in recent years implies that GCSCs regulate the drug resistance in GC through multiple mechanisms,including dormancy,drug trafficking,drug metabolism and targeting,apoptosis,DNA damage,epithelial-mesenchymal transition,and tumor microenvironment.In this review,we summarize current advancements regarding the relationship between GCSCs and drug resistance and evaluate the molecular bases of GCSCs in drug resistance.