基于磁柱型轴向均匀磁场产生装置的法拉第磁致旋光仪及实验设计

该文改进了法拉第磁致旋光仪的轴向磁场产生装置,设计核心是将多个沿厚度方向充磁的圆柱形钕铁硼永磁铁对称地放置在待测样品周围,具有磁场空间分布稳定、轴向磁场均匀、大小灵活可调等优点。此外,提出采用“相位法”测量法拉第磁致旋光角,通过与“消光法”比较表明,“相位法”能显著提高测量精度,测量误差小于0.5°。改进的磁场产生装置和测量方法也可用于法拉第反常色散滤光器等磁光旋转科研实验。

The complex roles of m^(6)A modifications in neural stem cell proliferation, differentiation, and self-renewal and implications for memory and neurodegenerative diseases

N6-methyladenosine(m^(6)A), the most prevalent and conserved RNA modification in eukaryotic cells, profoundly influences virtually all aspects of mRNA metabolism. mRNA plays crucial roles in neural stem cell genesis and neural regeneration, where it is highly concentrated and actively involved in these processes. Changes in m^(6)A modification levels and the expression levels of related enzymatic proteins can lead to neurological dysfunction and contribute to the development of neurological diseases. Furthermore, the proliferation and differentiation of neural stem cells, as well as nerve regeneration, are intimately linked to memory function and neurodegenerative diseases. This paper presents a comprehensive review of the roles of m^(6)A in neural stem cell proliferation, differentiation, and self-renewal, as well as its implications in memory and neurodegenerative diseases. m^(6)A has demonstrated divergent effects on the proliferation and differentiation of neural stem cells. These observed contradictions may arise from the time-specific nature of m^(6)A and its differential impact on neural stem cells across various stages of development. Similarly, the diverse effects of m^(6)A on distinct types of memory could be attributed to the involvement of specific brain regions in memory formation and recall. Inconsistencies in m^(6)A levels across different models of neurodegenerative disease, particularly Alzheimer's disease and Parkinson's disease, suggest that these disparities are linked to variations in the affected brain regions. Notably, the opposing changes in m^(6)A levels observed in Parkinson's disease models exposed to manganese compared to normal Parkinson's disease models further underscore the complexity of m^(6)A's role in neurodegenerative processes. The roles of m^(6)A in neural stem cell proliferation, differentiation, and self-renewal, and its implications in memory and neurodegenerative diseases, appear contradictory. These inconsistencies may be attributed to the timespecific nature of m^(6)A and its varying effects on distinct brain regions and in different environments.

Timing effect of high temperature exposure on the plasticity of internode and plant architecture in maize

The occurrence of high temperature(HT)in crop production is becoming more frequent and unpredictable with global warming,severely threatening food security.The state of an organ’s growth and development is largely determined by the temperature conditions it is exposed to over time.Maize is the main cereal crop,and its stem growth and plant architecture are closely related to lodging resistance,and especially sensitive to temperature.However,systematic research on the timing effect of HT on the sequentially developing internode and stem is currently lacking.To identify the timing effect of HT on the morphology and plasticity of the stem in maize,two hybrids(Zhengdan 958(ZD958),Xianyu 335(XY335))characterized by distinct morphological traits in the stem were exposed to a 7-day HT treatment from the V6 to V17 stages(Vn presents the vegetative stage with n leaves fully expanded)in 2019-2020.The results demonstrated that exposure to HT during V6-V12 accelerated the rapid elongation of stems.For instance,HT occurring at V7 and V12 specifically promoted the lengths and weights of the 3rd-5th and 9th-11th internodes,respectively.Meanwhile,HT slowed the growth of internodes adjacent to the promoted internodes.Interestingly,compared with control,the plant height was significantly increased soon after HT treatment,but the promotion effect became narrower at the subsequent flowering stage,demonstrating a self-adjusting mechanism in the maize plant in response to HT.Importantly,HT altered the plant architectures,including a rising of the ear position and increase in the ear position coefficient.XY335 exhibited greater sensitivity in stem development than ZD958 under HT treatment.These findings improve our systematic understanding of the plasticity of internode and plant architecture in response to the timing of HT exposure.

Application of multidisciplinary in situ simulation training in the treatment of acute ischemic stroke: a quality improvement project

BACKGROUND:Ischemic stroke refers to a disorder in the blood supply to a local area of brain tissue for various reasons and is characterized by high morbidity,mortality,and disability.Early reperfusion of brain tissue at risk of injury is crucial for the treatment of acute ischemic stroke.The purpose of this study was to evaluate comfort levels in managing acute stroke patients with hypoxemia who required endotracheal intubation after multidisciplinary in situ simulation training and to shorten the door-to-image time.METHODS:This quality improvement project utilized a comprehensive multidisciplinary in situ simulation exercise.A total of 53 participants completed the two-day in situ simulation training.The main outcome was the self-reported comfort levels of participants in managing acute stroke patients with hypoxemia requiring endotracheal intubation before and after simulation training.A 5-point Likert scale was used to measure participant comfort.A paired-sample t-test was used to compare the mean self-reported comfort scores of participants,as well as the endotracheal intubation time and door-to-image time on the fi rst and second days of in situ simulation training.The door-to-image time before and after the training was also recorded.RESULTS:The findings indicated that in situ simulation training could enhance participant comfort when managing acute stroke patients with hypoxemia who required endotracheal intubation and shorten door-to-image time.For the emergency management of hypoxemia or tracheal intubation,the mean post-training self-reported comfort score was signifi cantly higher than the mean pre-training comfort score(hypoxemia:4.53±0.64 vs.3.62±0.69,t=-11.046,P<0.001;tracheal intubation:3.98±0.72 vs.3.43±0.72,t=-6.940,P<0.001).We also observed a decrease in the tracheal intubation and door-to-image time and a decreasing trend in the door-to-image time,which continued after the training.CONCLUSION:Our study demonstrates that the implementation of in situ simulation training in a clinical environment with a multidisciplinary approach may improve the ability and confi dence of stroke team members,optimize the fi rst-aid process,and eff ectively shorten the door-to-image time of stroke patients with emergency complications.

Comprehensive integration of single-cell transcriptomic data illuminates the regulatory network architecture of plant cell fate specification

Plant morphogenesis relies on precise gene expression programs at the proper time and position which is orchestrated by transcription factors(TFs)in intricate regulatory networks in a cell-type specific manner.Here we introduced a comprehensive single-cell transcriptomic atlas of Arabidopsis seedlings.This atlas is the result of meticulous integration of 63 previously published scRNA-seq datasets,addressing batch effects and conserving biological variance.This integration spans a broad spectrum of tissues,including both below-and above-ground parts.Utilizing a rigorous approach for cell type annotation,we identified 47 distinct cell types or states,largely expanding our current view of plant cell compositions.We systematically constructed cell-type specific gene regulatory networks and uncovered key regulators that act in a coordinated manner to control cell-type specific gene expression.Taken together,our study not only offers extensive plant cell atlas exploration that serves as a valuable resource,but also provides molecular insights into gene-regulatory programs that varies from different cell types.

A Layered Energy-Efficient Multi-Node Scheduling Mechanism for Large-Scale WSN

In recent years, target tracking has been considered one of the most important applications of wireless sensornetwork (WSN). Optimizing target tracking performance and prolonging network lifetime are two equally criticalobjectives in this scenario. The existing mechanisms still have weaknesses in balancing the two demands. Theproposed heuristic multi-node collaborative scheduling mechanism (HMNCS) comprises cluster head (CH)election, pre-selection, and task set selectionmechanisms, where the latter two kinds of selections forma two-layerselection mechanism. The CH election innovatively introduces the movement trend of the target and establishesa scoring mechanism to determine the optimal CH, which can delay the CH rotation and thus reduce energyconsumption. The pre-selection mechanism adaptively filters out suitable nodes as the candidate task set to applyfor tracking tasks, which can reduce the application consumption and the overhead of the following task setselection. Finally, the task node selection is mathematically transformed into an optimization problem and thegenetic algorithm is adopted to form a final task set in the task set selection mechanism. Simulation results showthat HMNCS outperforms other compared mechanisms in the tracking accuracy and the network lifetime.

METTL5 promotes cell proliferation,invasion,and migration by up-regulating Toll-like receptor 8 expression in colorectal cancer

BACKGROUND N6-methyladenosine(m6A)modification represents the predominant alteration found in eukaryotic messenger RNA and plays a crucial role in the progression of various tumors.However,despite its significance,the comprehensive investigation of METTL5,a key m6A methyltransferase,in colorectal cancer(CRC)remains limited.AIM To investigate the role of METTL5 in CRC.METHODS We assessed METTL5 expression levels in clinical samples obtained from CRC patients as well as in CRC cell lines.To elucidate the downstream targets of METTL5,we performed RNA-sequencing analysis coupled with correlation analysis,leading us to identify Toll-like receptor 8(TLR8)as a potential downstream target.In vitro functional assessments of METTL5 and TLR8 were conducted using CCK-8 assays,scratch assays,as well as assays measuring cell migration and invasion.RESULTS Our findings reveal a pronounced upregulation of METTL5 expression in both CRC cells and tissues,which correlated significantly with an unfavorable prognosis.In vitro experiments unequivocally demonstrated the oncogenic role of METTL5,as evidenced by its promotion of CRC cell proliferation,invasion,and migration.Notably,we identified TLR8 as a downstream target of METTL5,and subsequent down-regulation of TLR8 led to a significant inhibition of CRC cell proliferation,invasion,and tumor growth.CONCLUSION The heightened expression of METTL5 in CRC is strongly associated with clinicopathological features and a poor prognosis,thereby underscoring its potential utility as a critical marker for facilitating early diagnosis and prognostication in CRC.

西藏纳木错沿岸表层水体浮游细菌群落结构及生态功能预测

浮游细菌群落对高原湖泊变化具有高度响应性,并且会影响高原湖泊生境的地球化学平衡。因此,了解高原湖泊中浮游细菌群落的分布特征,阐明其在高原湖泊生态系统中的生态功能具有重要科学意义。2021年5月对纳木错沿岸浮游细菌群落分布特征进行了调查研究,并采用16S rDNA高通量测序技术对样品进行分析,通过α-多样性指数分析浮游细菌群落的差异性,通过共现网络分析浮游细菌群落之间的相互作用,利用Pearson相关系数衡量理化因子与α-多样性指数的相关性,采用冗余分析(RDA)探讨水体理化因子对浮游细菌群落结构的影响,并基于PICRUSTt2对纳木错浮游细菌进行功能预测。结果表明:浮游细菌群落主要由变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、放线菌门(Actinobacteria)、蓝细菌门(Cyanobacteria)和厚壁菌门(Firmicutes)组成,其中变形菌门相对丰度最高,主要包括γ-变形菌纲(Gamma-proteobacteria)和α-变形菌纲(Alpha-proteobacteria);噬氢菌属(Hydrogenophaga)和嗜冷菌属(Algoriphagus)为相对优势菌属。α-多样性指数表明,纳木错浮游细菌群落比较丰富。共现网络节点间关系以正相关为主;总溶解固体量(TDS)和盐度(Sal)是影响纳木错浮游细菌群落结构的关键因子。功能预测结果显示,纳木错浮游细菌群落功能主要涉及代谢、遗传信息处理、环境信息处理等6类生物代谢通路,以及膜运输、氨基酸代谢、碳水化合物代谢等46个子功能。综上所述,纳木错浮游细菌群落结构在各样点间存在一定差异,浮游细菌在门级水平上类群间相互作用主要为协同作用,其群落结构是多个因子共同作用的结果。研究阐明了纳木错浮游细菌群落组成和功能及其与环境因子的相互联系,可为当地生态环境保护提供科学依据。

无人机自主抓取仿生机械手的设计

目的:设计一种无人机自主抓取仿生机械手,以实现无人机在飞行过程中精准抓取物体。方法:该机械手利用红外感应技术抓取物体,由外壳、支撑架、旋转齿轮、中央转轴、中央绕线盘、尼龙线(3根)、旋转电动机(2个)、扭簧(3个)、机械爪(3个)、机械爪固定装置(3个)、红外感应装置和Arduino开发板等组成。其中外壳采用聚乳酸材料进行3D打印,支撑架、旋转齿轮、中央转轴、中央绕线盘、机械爪采用光敏树脂进行3D打印,机械爪打印完成后再用橡胶材料浇注形成弹性结构;Arduino开发板采用OpenCM9.0控制器,可对红外感应装置和旋转电动机进行供电与控制。结果:经测试,该机械手能够实现张开与闭合操作,且可以在0.11~0.15 s完成张开—感应—启动—抓取的过程。结论:该机械手质量轻、负载低、抓取效率高,可满足无人机自主抓取物体的需求。

康莱特注射液联合化疗对晚期非小细胞肺癌患者血清肿瘤标志物的影响

目的探讨康莱特注射液联合化疗对晚期非小细胞肺癌患者血清肿瘤标志物的影响。方法将200例晚期非小细胞肺癌患者按照治疗方式的不同分为单独化疗组和联合用药组,每组100例,单独化疗组采用常规化疗方案,联合用药组加用康莱特注射液治疗,两组均治疗2个疗程。比较两组患者的治疗总有效率、免疫功能指标、血清肿瘤标志物、生活质量以及不良反应发生率。结果联合用药组患者的总有效率明显高于单独化疗组,差异有统计学意义(P﹤0.01)。治疗后,联合用药组患者CD3^(+)、CD4^(+)、CD4^(+)/CD8^(+)及生命质量测定量表各维度评分均明显高于单独化疗组,血清癌胚抗原、糖类抗原125、糖类抗原19-9水平均明显低于单独化疗组,差异均有统计学意义(P﹤0.01)。联合用药组患者不良反应总发生率低于单独化疗组,差异有统计学意义(P﹤0.05)。结论康莱特注射液联合化疗可有效改善晚期非小细胞肺癌患者的免疫功能,降低血清肿瘤标志物水平和不良反应发生率,提高生活质量,疗效确切。

色林错表层水体真核微生物多样性和群落分布格局

真核微生物作为高原湖泊生态系统食物网的关键组成部分,对维持高原湖泊生态平衡和促进生态系统营养流动过程至关重要。为研究色林错表层水体真核微生物多样性及其群落结构,2022年6月对色林错南岸(NA)、北岸(BA)和入水口(RSK)表层水体进行采样。基于18S rRNA基因高通量测序技术对样品进行分析,通过α多样性指数认识真核微生物群落的差异性,利用Pearson相关系数衡量理化因子与α多样性指数的相关性,并采用冗余分析(RDA)探究环境因子对真核微生物群落结构的影响。结果表明,调查共得到1343条OTU,分属9门15属,真核微生物群落主要由纤毛门(Ciliophora)和节足动物门(Arthropoda)组成。α多样性指数表明,色林错表层水体真核微生物群落多样性较低。NMDS分析及ANOSIM检验显示,真核微生物群落的区域间(NA、BA、RSK)差异大于区域内差异。Pearson相关性分析表明,电导率(EC)、总溶解固体量(TDS)和盐度(Salt)与α多样性指数显著相关。RDA分析结果表明,EC、TDS和Salt是影响色林错表层水体真核微生物群落结构的主要环境因子。本文阐明了色林错真核微生物群落结构组成情况及与环境的关系,为未来色林错收缩或扩张变化后的真核微生物群落动态研究提供参考依据。

农药作用下的根际微生物相对丰度变化研究进展

在我国农业生产中,农药残留一直是一个难以解决的问题。农药残留会给人类身体、农业用地以及其他生物类群带来不良影响。根际微生物作为植物根际土壤中物质交换和能量流动的重要生物类群,研究农药对其多样性的影响十分必要。研究发现:农药作用下的根际微生物多样性主要与农药适应性微生物的数量、农药种类、农药作用机制、农药半衰期、农药施用方式以及施用时间长短有关。此外,研究发现根际微生物还能直接或间接地应用于农残处理中。该文根据相关研究为土壤环境微生物多样性保护、农业用地保护、农产品生产及农残处理提供了新的思路。

湖泊生态系统中的真菌及其作用研究进展

真菌是生态系统中的主要分解者,在生态系统的物质和能量循环中扮演着重要角色。目前关于真菌多样性的研究都来自陆地环境,而水生环境的真菌多样性却未得到充分开发。湖泊真菌十分丰富,总结国内外对于湖泊中真菌的研究现状,介绍在湖滨带、浅水区、深水层和沉积物中的真菌分布,分析湖泊中真菌与病毒、细菌、原生动物及真菌之间的相互作用和真菌在湖泊生态系统中的作用(水生植物残体的分解、有机质处理的时空过程),提出湖泊真菌研究与应用前景展望。

Correlation between Hypovitaminosis D Status and Hyperactivation of IL-6/STAT3 Signaling in Clear Cell Renal Cell Carcinoma

Objective:To analyze serum vitamin D levels in patients with clear cell renal cell carcinoma(ccRCC)by flow cytometry and to investigate the relationship between hypovitaminosis D status and hyperactivation of IL-6/STAT3 signaling in ccRCC.Methods:Eighty patients diagnosed with ccRCC by our oncology department from January 2019 to December 2021 were selected as study subjects,and the control subjects were selected from patients who were receiving health check-up from our hospital(matched according to case group:control group,1:2),with 160 healthy patients.All serum samples collected from the case-control subjects were allowed to stand for 1–2 hours,centrifuged at 3000 rpm for 10 minutes,and stored in a-80°C refrigerator,from which they were removed and thawed to measure 25-hydroxyvitamin D(25(OH)D)and interleukin 6(IL-6)levels.Results:The blood calcium level of patients in the cancer group was significantly lower than that of patients in the non-cancer group,and the difference was statistically significant(P<0.05).The IL-6 level of the cancer group was significantly higher than that of the non-cancer group.In high vitamin D state,the IL-6 level of the non-cancer group was higher than that of the cancer group,and the average concentration of IL-6 in both the cancer group and the non-cancer group was significantly higher in low vitamin D state compared with high vitamin D state(P<0.05);the correlation between hypovitaminosis D status and renal Ki-67 was found to be positive.Conclusion:The results showed that serum IL-6 levels were elevated in the cancer group and circulating serum 25(OH)D levels were negatively correlated with IL-6 levels.In addition,signal transducer and activator of transcription 3(STAT3)signaling in RCC tissues was activated in ccRCC patients and in those with low vitamin D status among the cancer group and was higher than that in those with high vitamin D status.These results suggest that hypovitaminosis D status in ccRCC patients is associated with activated IL-6/STAT3 signaling and the activation of tumor proliferation markers proliferating cell nuclear antigen(PCNA),cyclin D1,and Ki-67.

Clinical Internship Teaching Management During the COVID-19 Epidemic

Against the backdrop of the global COVID-19 pandemic,the teaching and management of clinical medical interns have been facing tremendous challenges.When interns majoring in clinical medicine enter the internship position,they lack self-protection awareness and have limited ability to respond to unexpected public health events.This article explores the cognitive situation,existing problems,and improvement measures of clinical medical interns in the post-epidemic era.Therefore,this article proposes a series of improvement measures,including strengthening epidemic training and education for interns,enhancing personal protective awareness,and lastly achieving the role transition from intern to doctor.

基于自适应逆控制的永磁同步电机调速系统

针对永磁同步电机的反馈控制方法要兼顾系统动态性和抗扰性需求,在双闭环的矢量控制中采用具有扰动消除环节的自适应逆控制方法,能够避免系统的不稳定现象,提高系统的抗扰性能。首先,转速环采用基于前馈控制的自适应逆控制器,通过归一化的最小均方滤波算法使得转速误差能够快速收敛,并通过在线修正控制器权值,得到近似线性化的被控对象的逆模型。其次,为了抑制和消除电机参数摄动和外部扰动对系统的影响,采用扩张状态观测器对系统的扰动进行观测并补偿,同时提高系统动态性能和抗扰性能。最后,通过实验和仿真验证了所提方法的有效性。

老年非酒精性脂肪性肝病的营养状况及能量代谢特点

背景随着全球人口老龄化和非酒精性脂肪性肝病(nonalcoholic fatty liver disease,NAFLD)增长,老年NAFLD人群特点的研究尤为重要.目的观察老年NAFLD患者的营养状态和能量代谢特点.方法回顾性分析2017-01/2019-01天津市第三中心医院消化科就诊的NAFLD老年患者118例,进行人体成分分析仪分析及应用代谢车评估营养及能量代谢指标,与老年非脂肪肝组进行比较.统计分析中正态分布计量资料采用独立样本t检验,非正态分布计量资料采用Mann-Whitney U检验,二元Logistic回归分析老年NAFLD发生的危险因素.结果人体成分分析显示老年NAFLD组腰臀脂肪比、体脂肪含量较老年非脂肪肝组明显增加(腰臀脂肪比0.95 vs 0.92,体脂肪27.20 kg vs 19.60 kg,P<0.005);代谢车测定结果显示老年NAFLD组静息能量消耗均高于老年非脂肪肝组(1769.00 kcal/d vs 1323.00 kcal/d,P<0.05);进一步比较老年NAFLD患者轻度脂肪肝组与中重度脂肪肝组,轻度脂肪肝组体脂肪、腰臀脂肪比、基础代谢、静息能量消耗明显低于中重度脂肪肝患者.结论在老年NAFLD患者中存在营养失衡和能量代谢紊乱,随脂肪肝程度加重更为显著,通过人体成分分析仪和代谢车以综合评价和监测老年NAFLD患者的营养及能量代谢状态,为疾病干预治疗提供依据.

手术视频采集设备及应用现状进展

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