The connection of phytoplankton biomass in the Marguerite Bay polynya of the western Antarctic Peninsula to the Southern Annular Mode

Antarctic coastal polynyas are biological hotspots in the Southern Ocean that support the abundance of hightrophic-level predators and are important for carbon cycling in the high-latitude oceans.In this study,we examined the interannual variation of summertime phytoplankton biomass in the Marguerite Bay polynya(MBP)in the western Antarctic Peninsula area,and linked such variability to the Southern Annular Mode(SAM)that dominated the southern hemisphere extratropical climate variability.Combining satellite data,atmosphere reanalysis products and numerical simulations,we found that the interannual variation of summer chlorophyll-a(Chl-a)concentration in the MBP is significantly and negatively correlated with the spring SAM index,and weakly correlated with the summer SAM index.The negative relation between summer Chl-a and spring SAM is due to weaker spring vertical mixing under a more positive SAM condition,which would inhibit the supply of iron from deep layers into the surface euphotic layer.The negative relation between spring mixing and spring SAM results from greater precipitation rate over the MBP region in positive SAM phase,which leads to lower salinity in the ocean surface layer.The coupled physical-biological mechanisms between SAM and phytoplankton biomass revealed in this study is important for us to predict the future variations of phytoplankton biomasses in Antarctic polynyas under climate change.

Prognostic Role of Preoperative Tricuspid Annular Plane Systolic Excursion (TAPSE) in Mitral Valve Replacement (MVR) for Rheumatic Mitral Stenosis Patients

Tricuspid annular plane systolic excursion has been proposed as a simple and reproducible parameter for quantitative assessment of the right ventricular ejection fraction. The prognostic importance of preoperative TAPSE in patients with mitral valve replacement for rheumatic mitral stenosis patients is still under focused. Therefore, the objective of the study was to predict the outcome after MVR in rheumatic mitral stenosis patients in relation to preoperative TAPSE. This comparative cross-sectional study was conducted at the Department of Cardiac Surgery, National Heart Foundation Hospital and Research Institute. A total of 72 patients of rheumatic mitral stenosis patients who underwent mitral valve replacement were included in the study. They were divided into two groups: Group A and B. Group A included 36 patients with TAPSE 0.05) except for the preoperative TAPSE. Mean TAPSE of Group A was 13.17 (±1.40) and Group B was 18.61 (±1.57), the difference was statistically significant (p 0.05). Among the postoperative complications, including postoperative atrial fibrillation was higher in Group A (30.56%) than Group B (11.11%), mean ventilation time was higher in Group A (27.78%) than Group B (5.56%), length of intensive care was higher in Group A (33.33%) than Group B (11.12%), and hospital stay was higher in Group A (25.0%) than Group B (5.56%), (p < 0.05). Higher preoperative TASPE could be used as a prognostic tool for MVR in rheumatic mitral stenosis patients in our settings.

Slowing down of the summer Southern Hemisphere Annular Mode trend against the background of ozone recovery

20世纪末期,南半球热带外地区经历了显著的气候变化,包括夏季南半球环状模(SAM)的显著上升趋势,伴随着南极半岛的增暖和别林斯高晋海的海冰融化.这些趋势主要是由20世纪末期南极平流层臭氧消耗所驱动的.本文发现,自2001年左右以来,在南极平流层臭氧恢复的背景下,观测到的夏季SAM的上升趋势已经趋于平缓,验证了前人利用数值模拟预测的夏季SAM上升趋势减缓现象,与SAM在臭氧恢复后趋势只减缓但没有逆转不同,南极地表气温和海冰的趋势发生了逆转.南极半岛由变暖趋势转为降温趋势,别林斯高晋海域的海冰由融化趋势转为增多趋势.

Mechanical properties and microstructural evolution of rheocast A356 semi-solid slurry prepared by annular electromagnetic stirring

Nowadays,having an effective technique in preparing semi-solid slurries for rheocasting process seems to be an essential requirement.In this study,semi-solid slurry of A356 aluminum alloy was prepared by three-phase annular electromagnetic stirring(A-EMS)technique under different conditions.The effects of stirring current,pouring temperature and stirring time on microstructural evolution,mean particle size,shape factor and solid fraction were investigated.The rheocasting process was carried out by using a drop weight setup and to inject the prepared semi-solid slurry in optimal conditions into the step-die cavity.The filling behavior and mechanical properties of parts were studied.Microstructural evolution showed that the best semi-solid slurry which had fine spherical particles with the average size of~27μm and a shape factor of~0.8 was achieved at the stirring current of 70 A,melt pouring temperature of 670℃,and stirring time of 30 s.Under these conditions,the step-die cavity was completely filled at die preheating temperature of 470℃.The hardness increases by decreasing step thickness as well as die preheating temperature.Moreover,the tensile properties are improved at lower die preheating temperatures.The fracture surface,which consists of a complex topography,indicates a typical ductile fracture.

Mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device

Mass transfer performance of gas–liquid two-phase flow at microscale is the basis of application of microreactor in gas–liquid reaction systems.At present,few researches on the mass transfer property of annular flow have been reported.Therefore,the mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device are studied in the present study.We find that the main factors,i.e.,flow pattern,liquid film thickness,liquid hydraulic retention time,phase interface fluctuation,and gas flow vorticity,which influence the flow mass transfer property,are directly affected both by gas and liquid flow velocities.But the influences of gas and liquid velocities on different mass transfer influencing factors are different.Thereout,the fitting relationships between gas and liquid flow velocities and mass transfer influencing factors are established.By comparing the results from calculations using fitting equations and simulations,it shows that the fitting equations have relatively high degrees of accuracy.Finally,the Pareto front,namely the Pareto optimal solution set,of gas and liquid velocity conditions for the best flow mass transfer property is obtained using the method of multi-objective particle swarm optimization.It is proved that the mass transfer property of the gas–liquid two-phase flow can be obviously enhanced under the guidance of the obtained Pareto optimal solution set through experimental verification.

Elastic fiber degradation in the development of pediatric granuloma annulare:Report of 39 cases

BACKGROUND Granuloma annulare(GA)has diverse clinical manifestations,multiple subtypes,and unknown etiology and pathogenesis.Existing studies regarding GA in children are scarce.AIM To examine the correlation between clinical manifestation and histopathology of pediatric GA.METHODS A total of 39 patients under 18 years of age with both a clinical and pathological diagnosis of GA at Kunming Children's Hospital from 2017 to 2022 were retrieved.Their medical records were consulted,and clinical data of the children were recorded and summarized,including gender,age,disease site,etc.Existing wax blocks of skin lesion specimens of children and pathological films were retrieved for further study and relevant histology,including hematoxylin-eosin,Alcian blue,elastic fiber(Victoria blue-Lichon red method),and antacid staining.Finally,the children’s clinical manifestations,histopathological results,and special staining characteristics were analyzed.RESULTS The clinical manifestations of granuloma annulare in children were diverse:11 cases presented with a single lesion,25 with multiple lesions,and 3 with generalized lesions.The pathological typing comprised histiocytic infiltration,palisading granuloma,epithelioid nodular,and mixed types in 4,11,9,and 15 cases,respectively.Thirty-nine cases were negative for antacid staining.The positive rate of Alcian blue staining was 92.3%,and that of elastic fiber staining was 100%.The degree of elastic fiber dissolution and granuloma annulare histopathological typing were positively correlated(r=0.432,P<0.05).No correlation was found between clinical presentation and histopathological typing of the granuloma annulare in children.In the pathological diagnosis of granuloma annulare,the positive elastic fiber staining rate was higher than that of Alcian blue staining.A correlation was found between elastic fiber dissolution degree and histopathological staging.However,the differences in pathological staging may have been related to the pathological manifestation of granuloma annulare at different periods.CONCLUSION Elastic fiber degradation may be a critical step in the pathogenesis of pediatric granuloma annulare.This is also one of the first studies focused on granuloma annulare in children.

Generalized granuloma annulare in an infant clinically manifested as papules and atrophic macules:A case report

BACKGROUND Granuloma annulare(GA)has diverse clinical manifestations including papules,plaques,and nodules on the extremities that are skin-colored,pink,or purple.Approximately 15%of all GA cases are considered generalized GA.CASE SUMMARY Herein,we describe the case of a pediatric patient who initially presented with papules and later developed generalized atrophic macules.Upon examination,two different morphologic lesions were histopathologically confirmed:Epithelioid nodular GA and scattered histiocytic infiltrative GA.This patient exhibited rare clinical manifestations that differed throughout the course of the disease.The varying histopathological types and clinical manifestations of GA may be linked to the different stages of the disease.CONCLUSION This rare case demonstrates the different histopathological features of different stages and clinical manifestations of granuloma annulare in an infant.

Optimal Design of Aperture Illuminations for Microwave Power Transmission with Annular Collection Areas

This work presents an optimal design method of antenna aperture illumination for microwave power transmission with an annular collection area.The objective is to maximize the ratio of the power radiated on the annular collection area to the total transmitted power.By formulating the aperture amplitude distribution through a summation of a special set of series,the optimal design problem can be reduced to finding the maximum ratio of two real quadratic forms.Based on the theory of matrices,the solution to the formulated optimization problem is to determine the largest characteristic value and its associated characteristic vector.To meet security requirements,the peak radiation levels outside the receiving area are considered to be extra constraints.A hybrid grey wolf optimizer and Nelder–Mead simplex method is developed to deal with this constrained optimization problem.In order to demonstrate the effectiveness of the proposed method,numerical experiments on continuous apertures are conducted;then,discrete arrays of isotropic elements are employed to validate the correctness of the optimized results.Finally,patch arrays are adopted to further verify the validity of the proposed method.

环形桁架式空间薄膜展开机构运动精度可靠性建模与分析

空间薄膜展开机构的姿态和位置精度会对薄膜索网的工作形态产生影响。文章首先构建环形桁架式空间薄膜展开机构运动精度可靠性理论模型,然后基于ADAMS建立考虑展开机构杆长误差的参数化仿真模型,并采用蒙特卡罗法对展开机构进行运动精度可靠性仿真分析,求解运动精度可靠度。结果表明,以机构展开到位时折展杆支撑点所拟合的空间圆心坐标位置误差及半径误差作为其运动精度可靠性量化评价指标是正确的。该研究可为空间薄膜展开机构的可靠性设计提供参考。

三孔法腹腔镜十二指肠菱形吻合术治疗61例新生儿先天性环状胰腺

目的探讨腹腔镜手术治疗新生儿先天性环状胰腺的安全性和可行性。方法2015年6月~2023年6月我们对61例新生儿先天性环状胰腺采用三孔法腹腔镜手术,腹腔镜下分别游离环状胰腺远近端十二指肠,将十二指肠悬吊,近端扩张十二指肠横行切开,远端狭窄部分纵行切开,5-0 PDS线连续缝合十二指肠前后壁。结果3例中转开腹手术,余58例腹腔镜下完成手术。手术时间60~324 min,(163±57)min。术后经口开始喂养时间3~15 d,(6.8±2.9)d。住院时间4~83 d,中位时间17 d。1例术后12 d因肠粘连梗阻,行腹腔镜下肠粘连松解。1例术后3 d出现吻合口漏,行腹腔镜下修补。1例伴有早产,低出生体重,术后73 d出现重症感染、休克、弥散性血管内凝血,家属放弃治疗后死亡;余60例均治愈出院。60例术后胰腺超声见胰腺形态可,胰管无扩张,胆管无扩张,无胰腺炎。60例随访时间1~96个月,中位数37个月,均生长发育良好。结论腹腔镜手术治疗新生儿先天性环状胰腺是安全、可行的,对于早产儿、低出生体重儿围术期需精细化管理。

振腹环揉推拿法对失眠患者血清胃泌素、胃动素含量影响的临床研究

目的 探讨振腹环揉推拿法对失眠患者血清胃泌素、胃动素含量的影响。方法 在尊重临床伦理的前提下,招募40名胃失和降型失眠患者和20名健康志愿者,将40名患者随机分为治疗组和对照组,20名健康志愿者纳入健康组并未接受任何治疗;治疗组采取振腹环揉法进行治疗,每次30 min,每日1次;对照组采用保和丸口服,每次9 g,每日2次,5 d为1个疗程,共进行4个疗程;治疗前后,对2组患者的匹茨堡睡眠质量指数量表(PSQI)及阿森斯失眠量表(ASI)评分、胃泌素及胃动素检测结果进行统计学分析,并将胃泌素及胃动素检测结果与健康组进行对比。结果 2组治疗后与治疗前比较,各项数据均有明显改善,且治疗组较对照组改善明显,更接近健康组(P<0.05),差异具有统计学意义。结论 腹部推拿可显著地改善失眠患者的睡眠状态并提高睡眠质量,一定程度地提升了失眠患者的血清胃泌素及胃动素含量,进一步印证了“胃不和则卧不安”的经典理论的临床实用性。

烧结矿双级冷却工艺及装备技术研发与应用

烧结行业实践应用的余热回收方式主要是环冷机+余热锅炉与竖式冷却+余热锅炉,而将原烧结给料溜槽改为一级竖式冷却的双级冷却技术,可显著回收高品质余热。本文在介绍烧结双级冷却技术工艺及原理基础上,通过FLUENT流体仿真,对比了烧结双级冷却相对传统环冷机流场和温度场分布,并从冷却提效、余热回收增量、烧结矿增产和除尘增效4方面系统阐述了烧结双级冷却技术效果优势。结果表明,该技术可降低环冷机冷却风量约13%,提高过热蒸汽50℃,降低返矿率1%。该技术在湘潭钢铁新一烧360 m^(2)烧结机成功应用也表明,余热锅炉蒸汽产量可由吨矿约34 t/h增长到约40 t/h,增加发电量约为1200 kW·h年经济效益约为400万元。

复合材料双层球壳与环板耦合结构振动特性研究

以一阶剪切变形理论为基础,采用谱几何法对不同边界条件下复合材料双层球壳与环板耦合结构振动特性分析模型进行构建,其中采用人工虚拟弹簧技术模拟耦合结构的边界条件。根据耦合处的连接关系,通过布置耦合弹簧模拟器对子结构之间的耦合关系进行模拟。应用哈密顿原理对复合材料双层球壳与环板耦合结构的特征方程进行推导,对耦合结构的固有特性和稳态响应进行求解。将所得结果与有限元结果进行对比,验证了计算的正确性。分析了几何参数、材料参数对复合材料双层球壳与环板耦合结构振动响应的影响。

TMAD技术在无症状重度主动脉瓣狭窄患者预后评估中的价值

目的 探讨组织追踪二尖瓣环位移(tissue-tracking mitral annular displacement,TMAD)技术对保留射血分数(LVEF)无症状重度主动脉瓣狭窄(severe aortic stenosis,SAS)患者预后评估中的预测价值。方法 选取60例保留LVEF≥50%无症状SAS患者,依据随访有无发生主要心血管不良事件(MACE)分成A、B两组。采集患者连续4个心动周期心尖四腔、三腔及两腔切面动态图像,双平面辛普森法测量左心室LVEF。利用二维斑点追踪超声心动图技术获取左心室整体纵向应变(left ventricular globe Longitudinal straing,LVGLS),四腔心获取间隔与侧壁瓣环连线中点的纵向平均位移(TMAD),设备并可自动获取TMAD占舒张末期左心室长径的百分比(TMAD Midpt),检查后进行24个月的随访。比较两组上述各参数的差异,并分析TMAD Midpt预测SAS患者发生心脏相关事件的价值。结果 60例患者中A组21例,占35.0%,B组39例,占65.0%。A组TMAD Midpt及LVGLS显著低于B组,差异有统计学意义(P<0.01),两组间LVEF差异无统计学意义(P>0.05);A组患者心肌质量指数(myocardial mass index,MI)与B型脑钠肽(BNP)高于B组,差异有统计学意义(P<0.01),其他临床资料及超声心动图参数比较差异无统计学意义(P>0.05)。60例患者TMAD Midpt随着LVGLS的降低而降低,两者呈显著正相关(r=0.696,P<0.01)。ROC曲线分析,TMAD Midpt预测心脏事件与LVGLS具有相当的价值,曲线下面积分别为0.897、0.901(P<0.01)。结论 TMAD技术可以简便、快速地评估左心室射血分数保留的无症状SAS患者左心室功能损害,评估该类患者预后具有重要价值,值得临床推广应用。

TMAD定量评价慢性肾脏病患者左心室收缩功能的应用价值

目的探讨组织瓣环运动位移(TMAD)定量评价慢性肾脏病(CKD)患者左心室收缩功能的应用价值。方法选取30例CKD患者(实验组),再同期选取35例健康体检者(对照组)。应用组织斑点追踪技术快速获取心尖四腔及两腔心切面二尖瓣环四个位点运动位移,同期获取左心室整体纵向应变(GLS)及左心室整体圆周应变(GCS);应用线性相关分析TMAD参数与左心室射血分数(LVEF)、GLS间关系;绘制ROC曲线预测TAMD各参数诊断CKD患者左心室收缩功能减低效能。结果与对照组比较,实验组二维超声指标IVST、PWT、LVMI增大,差异有统计学意义(P<0.05);TMAD各参数T-AP4sep、T-AP4lat、T-AP4mid、T-AP4mid%、T-AP2int、T-AP2ant、T-AP2mid、T-AP2mid%、mTAMDmid及mTMADmid%均减低,差异有统计学意义(P<0.05);实验组T-AP4mid、T-AP2mid、mTMADmid、mTMADMmid%与LVEF呈正相关(r=0.522,r=0.344,r=0.475,r=0.413,P<0.05),与GLS呈负相关(r=-0.584,r=-0.430,r=-0.558,r=-0.620,P<0.01);mTMADmid%对预测CKD患者左心室收缩功能减低表现最好,mTMADmid%(AUC,0.93,敏感度、特异度分别为87.0%、95.0%,截断值11.9%)。结论应用TMAD可以早期定量评价CKD患者左心室收缩功能,且可重复性好。

TMAD评价保留射血分数无症状SAS病人左室功能受损及预后

目的:探讨组织追踪二尖瓣环位移(TMAD)技术评价保留射血分数无症状重度主动脉瓣狭窄(SAS)病人左室纵向运动功能及其对预后的预测价值。方法:入选60例保留射血分数无症状SAS病人,依据随访结果分成2组,其中有心血管相关事件定义为A组(21例),未发生心血管相关事件定义为B组(39例)。收集研究对象临床资料,所有入选病人检查后进行24个月随访。采集病人连续4个心动周期心尖四腔、三腔及两腔切面动态图像,双平面辛普森法测量左室射血分数(LVEF)。利用二维斑点追踪超声心动图技术获取左室整体纵向应变(LVGLS),四腔心获取间隔与侧壁瓣环连线中点的纵向平均位移(TMAD Midpt),设备并可自动获取TMAD占舒张末期左室长径的百分比(TMAD Midpt%)。比较2组上述各参数的差异,并分析TMAD Midpt%预测SAS病人发生心脏相关事件的价值。结果:60例病人中A组TMAD Midpt%及LVGLS低于B组(P<0.01),2组LVEF差异无统计学意义(P>0.05);A组病人心肌质量指数(MI)与B型脑钠肽(BNP)明显高于B组(P<0.01),2组其他临床资料及超声心动图参数比较差异均无统计学意义(P>0.05)。60例病人TMAD Midpt%随着LVGLS的降低而降低,两者呈正相关关系(r=0.696,P<0.01)。ROC曲线分析显示,TMAD Midpt%预测心脏事件与LVGLS具有相当的价值,曲线下面积分别为0.897、0.901(P<0.01)。结论:TMAD Midpt%在预测心脏事件发生方面与LVGLS具有相同的价值,而技术简便,可以快速地评估左室射血分数保留的无症状SAS病人左室功能损害及预测心脏事件的发生,值得临床推广应用。

储气库井在CO_(2)腐蚀作用下的环空带压安全管控

为加强储气库井在长期注采周期中的安全运行,考虑CO_(2)腐蚀对储气库井管柱的影响,建立管柱均匀腐蚀预测模型和剩余强度计算模型,在此基础上对储气库井A环空带压临界值进行计算,建立A环空带压临界控制图版。研究结果表明:在注采阶段,随着井深增大,油管柱腐蚀速率减小,而套管柱腐蚀速率先增大后减小;由于地层水和离子影响,采气阶段管柱衰减速率大于注气阶段;A环空带压临界值随油管的抗外挤强度减小而减小,油管的抗外挤强度为A环空带压临界值的主要影响因素;在储气库井正常运行时,选择初始壁厚更厚、初始强度更高的油管能够有效降低A环空带压临界值减小的速率。研究结果可为储气库井环空带压管理方案提供理论参考。

环形热管蓄冷保温箱空载均温性能研究

针对传统蓄冷箱箱内温度均匀性差的问题,提出环形热管结构蓄冷保温箱的设计,建立了空载均温性能的三维数值仿真模型,并进行了试验验证,对比分析了环形热管保温箱与常规结构蓄冷保温箱蓄冷板不同布置方式(四周布置、侧面+顶部+底部布置、中间布置)保温时间和温度均匀性的差异。结果发现,与常规结构蓄冷箱相比,环形热管结构的蓄冷保温箱的温度场、速度场均表现出较好的均匀性,其温度不均匀度为1.13,保冷时间为23 h。内部的环形热管在箱内形成环形流场,加强了对流换热,使整体温度均匀性更好。

光滑环形液体密封流态演变规律及静态稳定性研究

光滑环形密封静态刚度系数直接影响转子系统稳定性。为探究影响光滑环形液体密封的静态失稳机制及影响因素,应用计算流体力学方法建立光滑环形液体密封模型,研究密封在不同流动状态(层流、过渡流和湍流)、偏心率、进出口压力和转速下流动特性。结果表明:黏性效应是导致层流到过渡流状态下直接静态刚度先减后增主要原因;在过渡流和湍流中,黏性和惯性效应会使高偏心率下密封产生的气流力和刚度系数均为负值;随雷诺数增加,密封静态稳定性降低。

316L不锈钢掺杂SiC环状同轴送粉TIG熔覆层组织结构与性能

TIG熔覆是经济高效的表面修复方法,与传统的预置粉末法相比,同轴送粉法具有优良的适应性,但是试验研究相对较少.自主设计制造了环状同轴送粉TIG熔覆焊枪,与管状同轴送粉TIG熔覆焊枪相比,制造的熔覆层不存在熄弧位置凹坑、焊缝不够平直以及焊缝熔宽不一致等问题,而且具有更高的熔覆效率.结果表明,采用优化的焊接热输入、送粉量和SiC含量参数匹配,在316L不锈钢表面进行环状同轴送粉TIG熔覆,获得了外观优良的单层单道熔覆层、单层多道熔覆层.对熔覆层进行显微硬度测量、微观组织及元素成分分析、宏观电化学腐蚀试验、微区电化学腐蚀试验以及耐磨性能测试,并与母材进行了比对,环状同轴送粉TIG熔覆导入的SiC粉末有效地提升了熔覆层的耐蚀性与耐磨性.