Different concentrations of hyaluronic acid eye drops for dry eye syndrome: a systematic review and Meta-analysis

AIM:To compare high or low concentration of hyaluronic acid eye drops(HY)for dry eye syndromes(DES).METHODS:Randomized controlled trials(RCTs)comparing various concentrations of HY were searched in PubMed,Embase,Web of Science,Cochrane,SinoMed,CNKI,Wanfang Database,CQVIP,and Chinese journals databases between inception and July 2023.Pooled standardized mean differences(SMD)or weighted mean difference(WMD)with 95%confidence intervals(CI)from RCTs evaluating Schirmer’s I test(SIT),corneal fluorescein staining score(CFS),tear breakup time(TBUT),DES score(DESS),and Ocular Surface Disease Index(OSDI)were calculated.Sensitivity analysis,Egger’s test and Meta-regression analysis were performed for all indicators.RESULTS:We conducted a Meta-analysis of 10 RCTs that met the inclusion criteria,involving 1796 cases.High-concentrations group significantly improved the outcome of CFS according to random effects modelling(SMD,-3.37;95%CI,-5.25 to-1.48;P=0.0005).The rest of the results were not statistically significant,including indicators such as SIT,TBUT,DESS and OSDI.CONCLUSION:For dry eyes with positive corneal staining,a high concentration of HY is recommended,whereas in other cases,a high concentration of HY does not offer a more pronounced advantage over a low concentration of HY in the treatment of dry eyes.

Study on concentration distribution and detonation characteristics for non-axisymmetric fuel dispersal

The study of non-axisymmetric fuel dispersal and detonation can provide reference for the prevention of industrial cloud explosion accidents and the design of fuel air explosive(FAE).The concentration and detonation fields of 85 kg cylindrical and fan-shaped fuel are investigated by experiments and numerical simulations.A dynamic model of the whole process for fuel dispersal and detonation is built.The concentration distribution of fuel is used as the initial condition to calculate the detonation stage,thus solving the initial value problem of detonation field.The phase and component changes of fuel cloud at different locations are compared.The fuel cloud is divided into directions of 0°,90°,135°and 180°.The results show that the maximum cloud radius is 20.94 m in 135°and the minimum is 12.04 m in 0°.The diameter of the detonation fireball is 53.6 m,and the peak temperature is 3455 K.The highest peak overpressure is 3.44 MPa in 0°and the lowest is 2.97 MPa in 135°.The proportion of liquid phase in 0°is22.90%,and the fuel loss is 11.8% and 9% higher than that in 135°and cylindrical charge,respectively.The stable propagation distance of blast wave in 135°is 42.50% longer than 0°and 28.37% longer than cylindrical charge.

Dynamics and genetic regulation of macronutrient concentrations during grain development in maize

Nitrogen(N), phosphorus(P), and potassium(K) are essential macronutrients that are crucial not only for maize growth and development, but also for crop yield and quality. The genetic basis of macronutrient dynamics and accumulation during grain filling in maize remains largely unknown. In this study, we evaluated grain N, P, and K concentrations in 206 recombinant inbred lines generated from a cross of DH1M and T877 at six time points after pollination. We then calculated conditional phenotypic values at different time intervals to explore the dynamic characteristics of the N, P, and K concentrations. Abundant phenotypic variations were observed in the concentrations and net changes of these nutrients. Unconditional quantitative trait locus(QTL) mapping revealed 41 non-redundant QTLs, including 17, 16, and 14 for the N, P, and K concentrations, respectively. Conditional QTL mapping uncovered 39 non-redundant QTLs related to net changes in the N, P, and K concentrations. By combining QTL, gene expression, co-expression analysis, and comparative genomic data, we identified 44, 36, and 44 candidate genes for the N, P, and K concentrations, respectively, including GRMZM2G371058 encoding a Doftype zinc finger DNA-binding family protein, which was associated with the N concentration, and GRMZM2G113967encoding a CBL-interacting protein kinase, which was related to the K concentration. The results deepen our understanding of the genetic factors controlling N, P, and K accumulation during maize grain development and provide valuable genes for the genetic improvement of nutrient concentrations in maize.

Effects of different concentrations of nicotinamide on hematopoietic stem cells cultured in vitro

BACKGROUND In vitro expansion to increase numbers of hematopoietic stem cells(HSCs)in cord blood could improve clinical efficacy of this vital resource.Nicotinamide(NAM)can promote HSC expansion ex vivo,but its effect on hematopoietic stem and progenitor cells(HSPCs,CD34^(+)CD38)and functional subtypes of HSCs-shortterm repopulating HSCs(ST-HSCs,CD34^(+)CD38CD45RACD49f^(+))and long-term repopulating HSCs(LT-HSCs,CD34^(+)CD38CD45RACD49f^(+)CD90^(+))is not yet known.As a sirtuin 1(SIRT1)inhibitor,NAM participates in regulating cell adhesion,polarity,migration,proliferation,and differentiation.However,SIRT1 exhibits dual effects by promoting or inhibiting differentiation in different tissues or cells.We propose that the concentration of NAM may influence proliferation,differentiation,and SIRT1 signaling of HSCs.AIM To evaluate the effects and underlying mechanisms of action of different concentrations of NAM on HSC proliferation and differentiation.METHODS CD34^(+)cells were purified from umbilical cord blood using MacsCD34 beads,and cultured for 10-12 d in a serum-free medium supplemented with cytokines,with different concentrations of NAM added according to experimental requirements.Flow cytometry was used to detect phenotype,cell cycle distribution,and apoptosis of the cultured cells.Real-time polymerase chain reaction was used to detect the transcription levels of target genes encoding stemness-related factors,che mokines,components of hypoxia pathways,and antioxidant enzymes.Dichloro-dihydro-fluorescein diacetate probes were used to evaluate intracellular production of reactive oxygen species(ROS).Determination of the effect of different culture conditions on the balance of cytokine by cytometric bead array.RESULTS Compared with the control group,the proportion and expansion folds of HSPCs(CD34^(+)CD38)incubated with 5 mmol/L or 10 mmol/L NAM were significantly increased(all P<0.05).The ST-HSCs ratio and fold expansion of the 5 mmol/L NAM group were significantly higher than those of the control and 10 mmol/L NAM groups(all P<0.001),whereas the LT-HSCs ratio and fold expansion of the 10 mmol/L NAM group were significantly higher than those of the other two groups(all P<0.05).When the NAM concentration was>10 mmol/L,cell viability significantly decreased.In addition,compared with the 5 mmol/L NAM group,the proportion of apoptotic cells in the 10 mmol/L NAM group increased and the proportion of cells in S and G2 phase decreased.Compared with the 5 mmol/L NAM group,the HSCs incubated with 10 mmol/L NAM exhibited significantly inhibited SIRT1 expression,increased intracellular ROS content,and downregulated expression of genes encoding antioxidant enzymes(superoxide dismutase 1,peroxiredoxin 1).CONCLUSION Low concentrations(5 mmol/L)of NAM can better regulate the balance between proliferation and differentiation,thereby promoting expansion of HSCs.These findings allow adjustment of NAM concentrations according to expansion needs.

Rheological properties and concentration evolution of thickened tailings under the coupling effect of compression and shear

Cemented paste backfill(CPB)is a key technology for green mining in metal mines,in which tailings thickening comprises the primary link of CPB technology.However,difficult flocculation and substandard concentrations of thickened tailings often occur.The rheological properties and concentration evolution in the thickened tailings remain unclear.Moreover,traditional indoor thickening experiments have yet to quantitatively characterize their rheological properties.An experiment of flocculation condition optimization based on the Box-Behnken design(BBD)was performed in the study,and the two response values were investigated:concentration and the mean weighted chord length(MWCL)of flocs.Thus,optimal flocculation conditions were obtained.In addition,the rheological properties and concentration evolution of different flocculant dosages and ultrafine tailing contents under shear,compression,and compression-shear coupling experimental conditions were tested and compared.The results show that the shear yield stress under compression and compression-shear coupling increases with the growth of compressive yield stress,while the shear yield stress increases slightly under shear.The order of shear yield stress from low to high under different thickening conditions is shear,compression,and compression-shear coupling.Under compression and compression-shear coupling,the concentration first rapidly increases with the growth of compressive yield stress and then slowly increases,while concentration increases slightly under shear.The order of concentration from low to high under different thickening conditions is shear,compression,and compression-shear coupling.Finally,the evolution mechanism of the flocs and drainage channels during the thickening of the thickened tailings under different experimental conditions was revealed.

Effect of low concentration electrolytes on the formation and corrosion resistance of PEO coatings on AM50 magnesium alloy

In this paper,the formation process,morphology,and electrochemical performance of PEO coatings on AM50 magnesium alloy prepared in low concentration phosphate,aluminate,and phosphate-aluminate electrolytes were systematically studied.The results show that the coatings prepared from the phosphate electrolytes have a higher thickness and better corrosion resistance properties compared to the other electrolytes.The coatings prepared from low concentration phosphate-aluminate mixed electrolytes have slightly thinner thickness,a similar coating structure and an order of magnitude lower value of electrochemical impedance compared with phosphate electrolyte coatings.The Coatings prepared from low concentration aluminate electrolytes have the lowest thickness and the worst corrosion resistance properties which gets close to corrosion behavior of the bare AM50 under the same test conditions.Considering application,coatings prepared from single low concentration phosphate electrolytes and low concentration phosphate-aluminate electrolytes have greater potential than single low concentration aluminate coatings.However,reducing the electrolyte concentrations of coating forming ions too much has negative influence on the coating growth rate.

A multi-scale second-order autoregressive recursive filter approach for the sea ice concentration analysis

To effectively extract multi-scale information from observation data and improve computational efficiency,a multi-scale second-order autoregressive recursive filter(MSRF)method is designed.The second-order autoregressive filter used in this study has been attempted to replace the traditional first-order recursive filter used in spatial multi-scale recursive filter(SMRF)method.The experimental results indicate that the MSRF scheme successfully extracts various scale information resolved by observations.Moreover,compared with the SMRF scheme,the MSRF scheme improves computational accuracy and efficiency to some extent.The MSRF scheme can not only propagate to a longer distance without the attenuation of innovation,but also reduce the mean absolute deviation between the reconstructed sea ice concentration results and observations reduced by about 3.2%compared to the SMRF scheme.On the other hand,compared with traditional first-order recursive filters using in the SMRF scheme that multiple filters are executed,the MSRF scheme only needs to perform two filter processes in one iteration,greatly improving filtering efficiency.In the two-dimensional experiment of sea ice concentration,the calculation time of the MSRF scheme is only 1/7 of that of SMRF scheme.This means that the MSRF scheme can achieve better performance with less computational cost,which is of great significance for further application in real-time ocean or sea ice data assimilation systems in the future.

Relationship between plasma risperidone concentrations and clinical features in chronic schizophrenic patients in China

BACKGROUND Prior studies have noted great variability in the plasma levels of risperidone(RIS).Plasma concentrations of RIS and its active moiety are highly variable and depend on absorption,metabolism,and other predictors of metabolic dysregulation;however,these factors are poorly understood and the association between metabolic change and change in psychopathology is uncertain.AIM To ascertain the characteristics of chronic schizophrenic patients treated with RIS,and to assess their relationship with plasma RIS levels.METHODS This was a descriptive cross-sectional study of 50 patients with a diagnosis of schizophrenic psychosis treated with RIS in a psychiatric service.The plasma concentrations of RIS and its metabolite 9-hydroxyrisperidone were determined by high performance liquid chromatography.The patients’demographic and clinical characteristics,and psychopathologies were assessed,and the associations between clinical variables and plasma levels of RIS were explored.RESULTS Male patients received higher doses of RIS than female ones,but plasma concentrations of RIS and risperidone+9-hydroxyrisperidone(active moiety)were higher in female patients.Age and the mean scores of the general psychopathology subscale of the Positive and Negative Syndrome Scale(PANSS)were significantly positively correlated with plasma concentrations of risperidone+9-hydroxyrisperidone adjusted for weight and dose in all 50 subjects.In male subjects,we found a statistically significant positive correlation between the concentrations of risperidone+9-hydroxyrisperidone in plasma/(dose×kg)and age,mean PANSS negative subscale scores,mean PANSS general psychopathology subscale scores,and mean PANSS total scores.CONCLUSION Long-term use of RIS should be closely monitored in older patients and females to minimize the risk of high concentrations which could induce side effects.

急性前壁ST段抬高型心肌梗死患者直接冠状动脉介入术后微循环阻力指数与左心室不良重构的相关性

目的:评估急性前壁ST段抬高心肌梗死(acute anterior ST elevation myocardial infarction,STEMI)患者直接经皮冠状动脉介入术(primary percutaneous coronary intervention,PPCI)后微循环阻力指数(index of microcirculatory resistance,IMR)与1年后左心室不良重构(left ventricular adverse remodeling,LVAR)之间的关系。方法:采用单中心回顾性队列研究,连续选择2014年1月至2017年8月在北京大学第三医院住院的前壁STEMI并行PPCI患者,术后即刻通过压力/温度导丝测量IMR。利用血清肌酸激酶(creatine kinase,CK)峰值评估梗死面积,心肌梗死(myocardial infarction,MI)后1 d和1年时评估超声心动图,将左心室舒张末期容积(left ventricular end-diastolic volume,LVEDV)较基线增加≥20%定义为LVAR。结果:共入选43例患者,平均年龄(58.7±12.4)岁。根据IMR正常参考值将患者分为两组,IMR>25(n=23)组较IMR≤25组(n=20)患者冠状动脉造影显示梗死相关血管完全闭塞率(95.7%vs.65.0%,P=0.029)更高,血清CK峰值水平更高[4090(383,15833)vs.1580(396,5583),P=0.004],室壁瘤发生率更高(30.4%vs.5.0%,P=0.021)。MI后1 d两组LVEDV差异无统计学意义[(111.0±18.8)mL vs.(115.0±23.6)mL,P=0.503],而1年后IMR>25组LVEDV明显高于IMR≤25组[(141.5±33.7)mL vs.(115.9±27.9)mL,P=0.018]。IMR>25组LVAR发生比例更高(47.4%vs.11.8%,P=0.024)。二元Logistics回归显示IMR[B=0.079,exp(B)(95%CI)为1.082(1.018~1.149),P=0.011]和血清甘油三酯(triglyceride,TG)水平[B=1.610,exp(B)(95%CI)为5.005(1.380~18.152),P=0.014]是患者MI后1年发生LVAR的预测因素,IMR对1年后发生LVAR具有良好的预测价值(曲线下面积=0.749,P=0.019),IMR>29为良好的临界点,敏感性81.8%,特异性68.0%。结论:STEMI患者PPCI术后即刻测定IMR可以反映微血管功能,而微血管功能障碍是STEMI后1年左心室不良重构的有力预测指标。

罗斯曼指数对老年髋膝关节置换后非计划再入院和并发症的影响

背景:人工髋膝关节置换术在老年群体中有广泛应用,但临床中缺乏对患者非计划再次入院和术后并发症的准确预测方法。目的:探讨罗斯曼(Rothman)指数对老年髋膝关节置换患者术后非计划再入院和并发症的影响。方法:选择遵义市第一人民医院骨科一病区2020年12月至2022年12月接受择期髋、膝关节手术患者153例为研究对象,根据出院后90 d内是否非计划再次入院分为再入院组(n=21)和非再入院组(n=132)。通过电子病历系统统计所有患者一般性资料,包括性别、年龄、体质量指数、合并糖尿病、合并高血压、手术关节类型等,参照文献评估Rothman指数,统计患者术后并发症。结果与结论:①再入院组和非再入院组患者性别、体质量指数、手术关节类型、住院时长比较差异无显著性意义(P>0.05),两组共病数量、年龄、Rothman得分比较差异有显著性意义(P<0.05);②多因素Logistics回归分析结果显示,共病数量、年龄和Rothman得分均是老年髋、膝关节疾病患者术后90 d再入院的独立影响因素(P<0.05);③受试者工作特征曲线分析结果表明,Rothman指数预测人工髋膝关节置换术后90 d再入院曲线下面积为0.824,敏感度为80.85%,特异度为78.85%,最大youden指数为0.597,最佳截断值为46分;④Rothman<46分的老年患者总并发症发生率高于Rothman≥46分的老年患者(P<0.05);⑤提示Rothman指数可较为准确地预测老年髋、膝关节疾病患者术后非计划再入院,同时Rothman指数低于46分者发生并发症总体风险较高,关节恢复较差,可用于临床中改善患者术后管理。

基于SPI-RRV指数中国气象干旱及其风险时空演变特征研究

为全面揭示变化环境下我国多维气象干旱特征,耦合气象干旱指数(SPI)和可靠性-回弹性-脆弱性(RRV)指数,提出了一种基于SPI-RRV指数的干旱风险评价方法,定量评价了中国气象干旱及其风险的时空演变特征。结果表明:SPI-RRV指数具有特征稳定和时空可比性强的特点,能够较为准确地评估气象干旱风险时空演变特征;南方平均干旱栅格比、干旱月占比和频次大于北方,湿润区和半湿润区干旱历时短、烈度大,半干旱区和干旱区干旱历时长、烈度相对较小;干旱高风险区转移具有显著年代际变化规律,空间上从西北向西南地区转移。

基于Tei指数评价蒽环类药物对急性白血病患儿心脏毒性的研究

目的应用超声技术监测急性白血病患儿使用蒽环类药物后的心功能,以期得到心功能早期变化的指标。方法按照入组与排除标准选取2018年3月至2020年12月昆明医科大学附属儿童医院白血病患儿,记录其常规心脏超声指标和组织多普勒,并应用TeiS、TeiRL、TeiM和TeiT评估心脏收缩功能的变化。结果正常组和用药前实验组常规心脏超声指标中LVEF的均值都在60%以上,FS、SV及EDV均在正常范围,常规指标、TDI和Tei指数无统计学意义(P>0.05);实验组累积剂量为200和250 mg/m^(2)组的TeiM与用药前存在显著差异(P<0.05);200和250 mg/m^(2)组与用药前的TeiRL存在显著差异(P<0.05);200和250 mg/m^(2)组与用药前的TeiT存在显著差异(P<0.05)。结论Tei指数可作为白血病患儿应用蒽环类药物后左右心功能的早期改变较敏感监测指标。

融合尺度与信心指数的三维表面重建算法

针对包含细小结构场景的三维表面重建精度和完整度难以提高的问题,提出一种融合三维点云尺度与信心指数的三维表面重建算法。构建了一个表面隐函数,采用高斯函数为其基函数,三阶贝塞尔函数为其权重函数,并根据点云尺度与信心指数大小自适应调整基函数覆盖范围与权重函数取值。采用八叉树存储与处理数据,根据点云尺度大小自适应划分八叉树结构,从而自适应调整表面隐函数三维采样密度。通过无约束等值面提取方法,提取隐函数等值面,从而得到三维表面。与几种典型表面重建算法对比实验,结果表明所提算法重建三维表面细节清晰,整体重建精度与完整度均有提高。

基于统计的语音传输指数预测方法实验对比

良好的言语可懂度是语言声厅堂声环境设计的重要目标,语音传输指数(STI)是言语可懂度的客观评价参量。在设计阶段就能对STI做出准确预测,对语言声厅堂的声环境控制具有重要意义。基于统计的STI预测方法是IEC 60268-16标准推荐的主要预测方法,但对于使用该方法时的影响因素以及预测精度,当前仍缺少系统性的实验对比研究。该文使用4个房间中13个测点共52种听音条件下的STI实测结果,分析了基于统计的STI预测方法的精度以及影响因素,结果表明:考虑和不考虑直达声的两种预测方法,都存在着系统偏差,预测结果普遍小于实测值;在距离声源较近测点的预测都产生了较大误差,在距离声源较远测点的预测误差相对较小;基于单指数衰变声场不考虑直达声的预测方法操作简单,但误差较大,52种听音条件的平均误差达到了-0.032,最大误差达到了-0.131;考虑直达声的预测方法误差相对较小,52种听音条件的STI平均误差为-0.018,最大误差为-0.080;预测精度主要受所使用的信噪比、扬声器的指向性、房间的声场条件等因素影响,并对这些因素的影响进行了对比分析。结果可为STI预测方法的使用者提供参考。

基于蒸散发干旱指数的子牙河流域干旱时空变化特征分析

为探究子牙河流域干旱时空分布特征,基于2001—2021年逐月降水和遥感蒸散栅格数据,采用标准化降水蒸散指数(SPEI)和标准化蒸散发亏缺指数(SEDI)表征流域干旱情况,运用Sen斜率估计和Mann-Kendall检验法分析了流域2001—2021年季尺度干旱时空分布及变化趋势,统计了干旱面积、干旱次数、干旱历时和干旱烈度等特征变量。结果表明:SPEI对子牙河流域旱情发生时间、程度和范围识别的准确率更高,2001—2021年流域SPEI呈上升趋势,表现出湿润化态势,冬季SPEI呈下降趋势,表现为干旱化态势,忻州、阳泉市等地存在显著干旱化的区域;流域各季节干旱面积占比呈现波动变化,部分年份出现大范围季节性干旱,夏旱和秋旱干旱面积占比最高,超过90%;忻州和阳泉市部分区域、石家庄市西部区域和衡水市北部区域呈现干旱次数少、历时长、烈度大的特点,邯郸和邢台市部分区域、衡水市南部区域、石家庄市东部区域表现为干旱次数多、历时短、烈度小的特征。

云南县域特色农业发展指数评价与实证分析——以云南省X县为例

本文在解析特色农业概念与内涵的基础上,结合云南发展“三个经济”的重大部署,根据OSM指标体系构建原则形成云南县域特色农业发展指数评价指标体系,利用收集的X县2022年特色农业发展截面数据,通过专家打分方式获得模糊综合评价集,运用AHP进行权重测度,综合得出X县特色农业发展指数为74.879。分析X县各级指标得分,一级指标“园区经济”和“基础设施建设”对当地的特色农业发展贡献最大;“资源经济”和“口岸经济”评分均低于整体水平。在所有指标中,“资源经济”的“特色农产品认证”和“品牌影响力”两个指标和“口岸经济”的“口岸通达度”和“经济外向度”两个指标是制约当地特色农业发展的重要因素。最后根据X县特色农业发展现状提出4条建议:一是要充分挖掘本土农业资源,着力彰显特色农业显示度;二是要提升特色农业品牌建设水平;三是要着眼总部经济,提升经济外向度;四是要强化科技投入,不断提升科技支撑特色农业发展的力度。

老年人群体质量指数与慢性代谢性疾病的关系

目的·评估老年人群体质量指数(body mass index,BMI)与慢性代谢性疾病发生风险的关系。方法·以2014—2021年在上海交通大学医学院附属仁济医院体检中心进行体检的老年人(≥60岁)为研究对象。收集其各项生化指标。由经过培训的护士测量其身高、体质量和血压。采用问卷法收集研究对象既往慢性代谢性疾病史。收缩压≥140 mmHg(1 mmHg=0.133 kPa)、舒张压≥90 mmHg或既往有高血压病史,定义为高血压。空腹血糖≥7.0 mmol/L或既往有糖尿病病史,定义为糖尿病。总胆固醇≥6.2 mmol/L、三酰甘油≥2.3 mmol/L或既往有脂代谢异常病史,定义为脂质代谢紊乱。BMI与高血压、糖尿病和脂质代谢紊乱之间的关系采用受试者操作特征(receiver operator characteristic,ROC)曲线和二元Logistic回归进行分析评估。结果·共收集59083例研究对象的资料,其中男性30807例,女性28276例,平均年龄(67.9±6.3)岁。高血压、糖尿病和脂质代谢紊乱的发生率分别为76.5%(45219/59083)、24.1%(14225/59083)和50.0%(29544/59083)。与60~74岁的老年人群相比,75岁及以上的老年人患高血压和糖尿病的比例更高,患脂质代谢紊乱和无代谢异常的比例更低。通过ROC曲线分析,BMI对于高血压、糖尿病和脂质代谢紊乱的切点值分别为24.3、23.9和23.9 kg/m^(2)。老年男性高血压和糖尿病的BMI切点值和老年女性十分接近(高血压BMI切点值:老年男性24.3 kg/m^(2)vs老年女性24.2 kg/m^(2);糖尿病BMI切点值:老年男性24.0 kg/m^(2)vs老年女性23.7 kg/m^(2)),但老年男性脂质代谢紊乱的BMI切点值明显高于老年女性(老年男性24.0 kg/m^(2)vs老年女性22.5 kg/m^(2))。60~74岁老年人的BMI对慢性代谢性疾病的切点值(24.2~24.7 kg/m^(2))高于75岁及以上的老年人(22.9~23.8 kg/m^(2))。结论·60~74岁老年人群应将BMI控制在24.0 kg/m^(2)以下,而75岁及以上老年人群应将BMI控制在23.0 kg/m^(2)以下,则有利于降低其慢性代谢性疾病的风险。

CMA-GEPS极端温度预报指数及2022年夏季极端高温预报检验评估

极端预报指数(EFI)是利用集合预报获取极端天气信息的有效工具之一。为提升CMA全球集合预报系统(CMAGEPS)对极端天气的预报能力,针对CMA-GEPS历史预报数据少且再预报数据缺乏、难以合理统计模式气候分布的难题,研究利用小样本确定性预报数据形成EFI所需模式气候分布的方法。采用2020年6月15日—2022年7月22日CMA全球高分辨率(0.25°×0.25°)确定性业务预报数据,通过一种时间、空间样本扩展方法建立了与较低分辨率(0.5°×0.5°)的CMA-GEPS预报模式版本匹配的各预报时效(1—10 d)逐月模式气候分布。使用CMA-GEPS业务预报和ERA5再分析数据评估了CMA-GEPS 2 m气温EFI对2022年夏季(6—8月)中外4个代表性区域极端高温的预报能力。基于相对作用特征曲线的检验结果表明,CMA-GEPS EFI在1—10 d的短、中期预报时效上均具备区分极端高温的能力。以最大TS评分为准则,确定了用于发布极端高温预警信号的EFI临界阈值。EFI的预报能力随预报时效延长呈下降趋势,且在不同区域的表现存在差异:对中国长江中下游地区极端高温的预报能力在各时效上均优于华北地区;欧洲西部地区1—7 d时效上的EFI预报能力高于欧洲中部地区,而欧洲中部地区8—10 d时效上的EFI预报能力更好。上述结果与2 m气温的集合预报质量随预报时效与空间位置而变化有关。经济价值模型的评估结果表明,基于EFI预报信息的风险决策存在一定的经济价值和参考价值。个例分析结果进一步展现了CMA-GEPS EFI能够在中期预报时效上发出极端高温早期预警的能力。

膳食炎症指数与胃肠道炎症性疾病关系研究进展

胃炎、胃溃疡、炎症性肠病和肠易激综合征是常见的胃肠道慢性炎症性疾病,饮食是炎症的主要决定因素,是降低胃肠道疾病风险的关键可改变因素。由于不同食物和营养素之间存在复杂的相互作用,因此,提出了评估膳食整体炎症潜力的新型工具—膳食炎症指数(dietary inflammatory index,DII),DII不仅可以量化评估受试者的整体膳食炎症效应,还能在不同个体之间进行比较,已经发现DII与多种胃肠道疾病有关,本文对DII与常见胃肠道慢性炎症性疾病之间的关系进行综述,为饮食干预防治胃肠道慢性炎症性疾病提供新的思路。

婴儿体脂指数的影响因素分析

目的探究不同性别婴儿体脂指数(FMI)的影响因素。方法于2021年10月至2022年12月,在山东省开展婴儿体成分的横断面研究,对研究对象进行电子问卷调查和体成分测量获取研究数据,最终纳入9291份有效数据,应用多因素线性回归分析不同性别婴儿FMI的影响因素。结果不同性别婴儿月龄与FMI具有显著正相关。与适于胎龄儿相比,大于胎龄儿的FMI增加(β值分别为0.086、0.078,P<0.001),小于胎龄儿的FMI降低(β值分别为-0.088、-0.072,P<0.001)。与6月龄以后添加辅食相比,4~6月龄添加辅食男女婴儿FMI均增加,差异均具有统计学意义(β值分别为0.099、0.053,P<0.001)。与父母亲体重正常相比、父母亲肥胖与婴儿FMI的增加显著相关(β值分别为0.058、0.070和0.054、0.058,P<0.001),母亲体重过低与婴儿FMI降低显著相关(β值分别为-0.039、-0.046,P=0.005、0.002)。妊娠期糖尿病与婴儿FMI降低显著相关(β值分别为-0.039、-0.046,P=0.005、0.002),妊娠期高血压与男婴FMI升高显著相关(β=0.028,P=0.038)。纯配方奶喂养对女婴FMI存在显著正向影响(β=0.029,P=0.046)。孕期增重不足对女婴FMI存在显著负向影响(β=-0.033,P=0.032)。结论影响婴儿身体成分的因素有胎龄别体重、喂养方式、辅食添加时间、母亲孕期增重及孕期疾病等,应在生命早期采取干预措施进行控制,预防子代代谢性疾病的发生。