Assessment of Effects of Concomitant Exposure to Sound, Heat, and Physical Workload Changes on Physiological Parameters in Five Different Combination Modes, a Controlled Laboratory Study

Exposure to sound,heat,and increased physical workload can change physiological parameters.This study was conducted to evaluate the effect of concomitant exposure to sound,heat,and physical workload changes on physiological parameters in controlled laboratory conditions.This experimental crosssectional study was conducted in 35 male university students with a mean age of 25.75 years and a mean BMI of 22.69 kg/m2.Systolic and diastolic blood pressure and heart rate were measured after 15 min rest in the laboratory,5 and 10 min after starting the experiment,and then after 20 min in controlled laboratory conditions in five combination modes.The combination modes were(Sound:65 dB,WBGT:22°C,Speed:1.7,Slope:10%),(Sound:65 dB,WBGT:22°C,Speed:3.4,Slope:14%),(Sound:95 dB,WBGT:22°C,Speed:1.7,Slope:10%),(Sound:65 dB,WBGT:32°C,Speed:1.7,Slope:10%),and(Sound:95 dB,WBGT:32°C,Speed:3.4,Slope:14%).Mixed model analysis and paired t-test were applied for analysis.The results showed that the mean physiological parameters(Systolic and diastolic blood pressure and heart rate)increased when different combination modes worsened(Sound from 65 to 95 dB,WBGT from 22°C to 32°C,speed from 1.7 to 3.4,and slope from 10%to 14%,and when sound:95 dB,WBGT:32°C,Speed:3.4,and Slope:14%).Moreover,the mean changes of systolic and diastolic blood pressure were significant in all conditions when compared with the reference condition(Sound:65 dB,WBGT:22°C,Speed:1.7,and Slope:10%).The mean heart rate changes were also significant except for exposure to the second condition(Sound:65 dB,WBGT:22°C,Speed:3.4,Slope:14%)and the third condition(Sound:95 dB,WBGT:22°C,Speed:1.7,Slope:10%).Exposure to hazardous levels of sound,heat,and workload has adverse effects on physiological parameters.Concomitant exposure to all three hazards has a synergistic effect and increases the adverse effect.

Physiological, Enzymatic and Molecular Changes of Acipenser schrencki Induced by Heat Exposure

[Objective] The paper was to understand the physiological, enzymatic and molecular changes of Acipenser schrencki induced by heat exposure. [Method] The effects of heat exposure on A. schrencki were investigated. The temperature was increased from(18± 0.5) ℃ by 0.08 ℃/min and respectively kept at(32±0.5) ℃ for 2, 4 and 6 h. The respiration rate, related biochemical indicators and heat shock protein 70(Hsp 70) mR-NA expression were investigated. [Result] At(32±0.5) ℃, the activities of total protein, albumin, globulin, urea nitrogen, ceatinine, malondialde-hyde, aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase fluctuated dramatically from 2 h to 6 h. Meanwhile, the respi-ration rate and Hsp 70 m RNA expression in heart, liver and spleen were significantly increased from 2 h to 6 h. In comparison, the lower respira-tion rate and tiny fluctuations in activities of biochemical indicators were consistent with the lower Hsp 70 expression. [Conclusion] During the process of heat stress, A. schrencki seems to be sensitive to such temperature, and manifests generally consistent gill breathing, biochemical indica-tors and Hsp70 gene expression, implying better heat tolerance.

Influence of heating and water-exposure on the liquid limits of GMZ01 and MX80 bentonites

Bentonite has been considered as a buffer material for embedding canisters with high-level radioactive waste（HLW） in deep geological repositories.GMZ bentonite deposit,located in Xinghe County,Inner Mongolia Autonomous Region,China was proposed as a buffer/backfill material for HLW repository in China.The liquid limits of natural Na-bentonite GMZ01 and commercial Na-bentonite MX80,which are previously heated at 80 ℃ and 95 ℃,respectively,and exposed to water for different times are measured.It is observed that the liquid limit of GMZ01 increases slightly at the beginning,and then decreases as the heating time increases,while the liquid limit of MX80 decreases with the heating time.The liquid limits of both GMZ01 and MX80 decrease with increasing water-exposure time.After the samples are heated at 80℃and 95 ℃ for several months,the mineralogical composition of GMZ01 does not exhibit evident change,whereas MX80 experiences some changes.In addition,the chemical composition,cation exchange capacity（CEC） and exchangeable cation of all the samples do not change significantly.

More extreme-heat occurrences related to humidity in China

极端日夜复合高温往往会造成更为严重的社会经济影响及健康风险,受到了广泛关注。本文基于ERA5逐小时资料,针对中国区域极端日夜复合湿热和高温事件的变化及其影响进行了比较分析.结果指出,中国区域夏季极端湿热和高温在空间分布上较为一致,强度高值区主要分布在南方地区,但高频中心主要出现在北方地区.两类事件发生频次在全国范围内均呈明显增加趋势,尤其在西部和北部地区.进一步研究表明,在中国大部分地区,湿度异常在极端湿热事件变化中有着十分重要的作用,部分区域甚至超过温度异常的影响。随着极端湿热事件的增加其影响也在加剧,自1961年以来中国暴露于极端湿热事件的人口数量和城市面积增速明显大于高温事件.

安徽阜阳夏季极端高温趋势分析与风险评估

基于1970~2022年安徽阜阳5个观测站点的资料,利用热指数对阜阳夏季极端高温进行了分析,并对阜阳高温风险及人口暴露度进行了评估。结果显示:阜阳高温日数呈增加趋势,大约为1.33 d/10 a,相应的热指数也呈增加趋势。热指数的增长趋势在周末两天明显低于周一到周五的工作日,这种周末效应在14:00(北京时间)表现得最为明显。阜阳夏季的高温低风险天数以0.85 d/10 a降低,而中风险天数以1.42 d/10 a增加,即正从低风险向中风险转变。2005~2022年阜阳的高温人口暴露度是1978~2000年的2倍多,其中人口因素贡献为17.32%,气候因素贡献为75.06%,人口和气候因素共同贡献了7.62%。

Effects of glutamine pretreatment on learning and memory in heat-exposed rats

BACKGROUND： Glutamine （Gin） pretreatment can protect neural cells from injuries due to heat, ischemia, hypoxia, endotoxemia, and inflammatory factors. OBJECTIVE： To observe the effects of Gin pretreatment on learning and memory, survival time, and rectal temperature in heat-exposed rats. DESIGN, TIME AND SETTING： The present randomized grouping, neurobehavioral experiment was performed at the Laboratory of Department of Pharmacology, Basic School of Medicine, Wuhan University between March and September 2007. MATERIALS： Twenty-four healthy, Wistar rats were included in this study. SPX-160B biochemistry incubator （Shanghai Experimental Equipment Co., Ltd., China）, probe electronic thermometer （11000 type, Maikepai Science and Technology Co., Ltd., China）, Y-type maze box used in conjunction with MG-2 maze stimulator （Zhangjiagang Biomedical Instrument Factory, China）, L-Gln （Batch No. 061218, 5 g/bottle, prepared into 10% aqueous solution, Amresco Company, USA） were used. METHODS： Twenty-four rats were randomly and evenly divided into 3 groups： heat-exposed, Gln low-lose, and Gln high-dose. Following learning and memory testing with the Y-maze, rats in the heat-exposed group were subjected to heat injury （40.5-41.5 ℃） in a biochemistry incubator. Rectal temperature was measured every 5 minutes. Thirty-five minutes after heat exposure, rats were removed and placed in the Y-type maze to test learning and memory again. Subsequently, the rats were returned to the same environment of thermal stimulation until they died. Rat survival time was recorded. Subsequent to learning and memory testing, rats in the Gin low-dose and high-dose groups received an i.p. injection of Gin （0.4 g/kg and 0.8 g/kg, respectively）, and were exposed to heat injury. The remaining experimental procedures remained the same as for the heat-exposed group. MAIN OUTCOME MEASURES： Rat learning and memory, rectal temperature, and survival time in heat exposure environment. RESULTS： （1） In the Y-maze experiment, the frequency for the heat-exposed group rats to move 15 successive times through the maze without any mistakes was 13 times greater prior to heat exposure. Thirty-five minutes after heat exposure, rat learning and memory were significantly decreased, i.e., frequency was 9/15 correct trials （P 〈 0.01 ）. Following Gln pretreatment, rat learning and memory noticeably improved The frequency of Gln low-dose and high-dose rats maintained 13/15 correct trials, which was not different compared with before heat exposure （P 〉 0.05）. （2） The heat-exposed group required 14 minutes to reach the rectal temperature of 39.5℃. After 2 hours of Gln pretreatment, the Gln low-dose and high-dose groups needed 18 and 20 minutes, respectively （P 〈 0.05）. （3） Following 2 hours ofGln pretreatment, the survival time of the Gln low-dose and high-dose groups was 66 and 69 minutes, which was prolonged by 18.2% （P 〈 0.05） and 21.7% （P 〈 0.01）, respectively, compared with the heat-exposed group （54 minutes）. CONCLUSION： A 2-hour Gln pretreatment can noticeably improve learning and memory, delay ascending speed of body temperature, and prolong survival time in heat-exposed rats in a dose-dependent manner.

Specific Enthalpy Based Heat Stress Index for Indoor Environments without Radiation Effect

Over 100 human thermal indices have been developed to predict the combined thermal impact on the body.In principle,these indices based on energy thermal budget equations should not only be the most complex but also be the most accurate.However,the simple indices based on algebraic or statistical models[e.g.,the wet-bulb globe temperature(WBGT)]continue to be the most popular.A new heat stress index,the enthalpy dry-bulb temperature(EnD)for indoor environments is developed and validated in this study.The EnD index is unique in that it uses the air specific enthalpy,not the wet-bulb temperature,to measure the latent heat transfer from the skin to the surrounding environment.Theoretically,the EnD index can be treated as the equivalent temperature based on the convective heat transfer coefficient h_(c).Comparison is made between the EnD index and the widely used WBGT index based on the experimental data taken from three independent studies available in the scientific literature.The results show that the EnD index can reduce the overestimation of the dry-bulb air temperature and thus reduce heat stress in most cases,especially for hot and humid environments.It can be concluded that the EnD index has the potential to replace the WBGT index as the standard heat stress index in the future.

Experimental study on the method of efficient heat acclimatization in macaques

Twenty-eight adult macaques were divided into five groups for differenttreatments.Of these five groups,groups 1 to 3 were exposed to heat once dailyfor 10d until the rectal temperature (RT) rose to 40℃,40.8℃ and 41.6℃,respectively.The other two groups (groups 4 and 5) were exposed to heat twicedaily and every other day,respectively,until the RT of both groups reached41.6℃.The method of heat exposure to obtain the required RT was to keep themacaques in a hot chamber (Td 41℃,Tw 38℃).Before and after theacclimatization period,the macaques were given a standard high temperature testin the same environment as the heat acclimatization (HA) period until the RTrose to 41.6℃.The results revealed that the animals in groups 3 to 5 whose RTin HA increased to 41.6℃ showed a significant HA effect by prolonging the dura-tion of exposure (P【0.05～0.001) and decreasing the RT (1.14～1.83℃),especiallyin the daily exposed group.Therefore,one of the most effective ways for devel-oping full acclimatization in macaques is to expose to heat once daily for 10duntil the RT rises to 41.6℃.

Thermal stability of multi-pray deposition heat resistant Al-Fe-V-Si alloy

Rapidly solidified Al 8.4Fe 1.3V 1.7Si heat resistant alloy was made by using multi layer spray deposition technique. Its thermal stability of mechanical properties was investigated by the means of tensile and hardness tests, thermal stability of microstructure by transmission electron microscopy (TEM), X ray diffraction (XRD). The results show that after heat exposure (HE) at 753?K for 500?h the tensile strength and hardness of Al Fe V Si alloy at 623?K maintains the same values as those at room temperature. HE dose not obviously affect the thermal stabilities of Al 12 (Fe,V) 3Si phase but the lattice constant of Al 12 (Fe,V) 3Si phase decrease.

间断性热暴露导致自发性高血压大鼠的胸主动脉损伤:基于激活AMPK/mTOR/ULK1通路

目的 探讨不同热暴露方式对自发性高血压大鼠胸主动脉血管损伤的影响及其机制。方法 选用自发性高血压大鼠(SHR),构建热暴露大鼠模型,分为对照组SHR-CN(n=9,饲养在24℃室温下),间断性热暴露组SHR-8(n=9,每天接受任意连续8 h热暴露,其余时间饲养在与对照组相同的条件下)和持续性热暴露组SHR-24(n=9,持续暴露在32℃高温下)。进行自噬和通路干预的SHRs,分别于热暴露前30 min腹腔注射自噬激活剂Rapa,抑制剂3-MA和AMPK抑制剂Compound C(CC)。。通过苏木素-伊红染色(HE)观察大鼠胸主动脉形态的变化;利用Western blot和免疫荧光(IF)分别检测高血压大鼠胸主动脉自噬相关因子Beclin1、LC3B和p62的表达情况;利用TUNEL检测高血压大鼠胸主动脉凋亡的情况,Western blot检测Caspase-3,Bax和Bcl-2的表达情况;用自噬的激活剂和抑制剂干预高血压大鼠后,检测自噬和凋亡相关因子的表达情况;免疫组化(IHC)检测通路相关因子的表达情况,大鼠腹腔注射AMPK抑制剂Compound C(CC)后,进一步观察通路及自噬的表达情况。结果 HE染色显示,SHR-8组胸主动脉内膜排列分布不完整,细胞分布紊乱。Western blot显示Beclin1、LC3II/LC3I表达增高,p62降低,差异均具有统计学意义(P<0.05)。TUNEL结果表明SHR-8组中凋亡阳性细胞数明显高于对照组。Western blot表明热暴露后Bax表达升高,Bcl-2表达降低,差异具有统计学意义(P<0.05)。3-MA抑制自噬的表达,同时凋亡表达降低,Rapamycin促进自噬和凋亡的表达。IHC显示,与SHR-CN相比,SHR-8组p-mTOR明显降低,p-AMPK和p-ULK1表达升高。腹腔注射CC降低了pAMPK和p-ULK1的表达,同时自噬相关因子LC3B和Beclin1表达降低。结论 不同热暴露下,间断性热暴露导致自发性高血压大鼠胸主动脉形态、自噬和凋亡相关因子表达变化显著,其作用机制可能是通过激活AMPK/mTOR/ULK1信号通路来实现的。

Ni-Mo-Cr镍基模型高温合金中热暴露条件对TCP相析出规律的影响

本文利用扫描电镜和透射电镜,对经过不同条件热暴露实验后的Ni-20Mo-10Cr(at.%)模型合金进行研究,分析析出TCP相的物相类型及元素分布,从而找到TCP相的析出规律。研究结果表明:样品经过900℃/3 h热暴露实验后析出μ相,EDS结果表明合金中产生Mo元素的富集,Cr元素并不富集。样品经过800℃/20 h+900℃/3 h热暴露实验后析出δ相,EDS结果表明合金中产生Mo元素和Cr元素的富集。

Ta含量对铸造高温合金DZ411长期热暴露过程中γ′相粗化的影响

借鉴材料基因工程中高通量实验的做法,采用快速凝固技术和定向凝固技术制备含Ta浓度梯度的定向合金,并在900℃进行长期热暴露实验,研究不同Ta浓度对铸造高温合金热暴露中γ′相生长速率的影响。通过对不同热暴露时间γ′相尺寸变化的统计,结合粒子粗化理论计算发现,随着Ta浓度增加,粗化速率常数一直在减小。通过合金中有效扩散系数计算发现,热暴露前期,高Ta浓度处的γ′相形成元素平均扩散系数较低,使得γ′相生长速率放缓。在长期热暴露后期,高Ta浓度处γ′相生长速率依旧缓慢,并且γ相基体间产生了大量位错,经测量,两相的相界面间的晶格错配度减小,阻碍了相形成元素向γ′相内迁移,导致γ′相生长速率减缓。

一种医用防护面屏的设计与应用

本文介绍一种医用防护面屏的设计与应用,在降低暴露风险的同时提升医务人员舒适感。该医用防护面屏也有助于日常室外作业人员的有效防暑降温,降低中暑风险,提升工作效率。

Sn诱导Al−4Cu合金中θ′相向θ相的相转变机制及其对合金高温强度的影响

通过显微组织观察和拉伸试验研究添加0.02%Sn(质量分数)对Al−4Cu合金在573 K高温热暴露过程(100 h)中θ′向θ相转变机制和高温强度的影响。研究结果表明,Sn微合金化能完全改变Al−4Cu合金在持久热暴露过程中θ′相向θ相的相转变机制。在未添加Sn的Al−4Cu合金中,棒状θ相在粗化后的盘状θ′相的表面形核和生长。然而,当添加少量Sn后,θ相首先在β-Sn颗粒上异质形核,然后形成粗大的针状相。由于Sn微合金化能提高Al−4Cu合金中θ′相的数密度并降低其尺寸,因此,Al−4Cu合金在T5状态下的室温和573 K高温下的屈服强度得到显著提高。然而,Sn微合金化能同时促进持久热暴露过程中θ′相向θ相的转变,导致Al−4Cu合金在热暴露后的高温(573 K)强度显著降低。

城市人居环境热脆弱性评估及空间分布特征--以成都市主城区为例

受全球气候变暖及城市热岛效应的双重影响,高温热浪事件逐渐成为城市面临的主要灾害之一,尤其是长期居住在高密度建设、人口密集主城区的居民更易受到热岛效应带来的不良影响。因此,如何在街道尺度下通过城市人居环境热脆弱性评估进行易受灾空间分布的识别,并提出相应的适应策略成为当下气候适应性研究领域的热点。论文以成都市主城区为例,以街道为研究单元,整合人口数据、社会经济数据、POI、遥感影像等多源数据,通过构建以暴露度、敏感性及适应能力为准则层的城市人居环境热脆弱性评价指标体系,对成都市主城区进行综合评价,并识别出主城区夏季人居环境热脆弱性空间分布特征及高脆弱性街道的致脆主导因子。研究发现:成都市主城区人居环境热脆弱性呈现“内高外低”及“西北高东南低”的分布特征。同时,进一步划分不同致脆类型街道为“高暴露主导区”“高敏感主导区”及“低适应主导区”,并针对不同类型分区提出相应的气候适应性措施。

Physiological and subjective thermal responses to heat exposure in northern and southern Chinese people

When studying the thermal adaptation of building occupants,understanding the effects of different thermal experiences on adaptation is necessary,particularly for moderate and severe heat exposure.However,this area has seen limited research.Further,skin temperature,a common parameter for quantifying thermal sensation,may insufficiently reflect the automatic thermoregulation of the human body.This study investigates the effects of long-term heat exposure on the human body using multiple physiological and subjective indexes.Two heat exposure experiments were conducted on healthy male participants from northern and southern China.Participant responses,including skin temperature,heart rate,heart rate variability,blood volume pulse(BVP),subjective thermal comfort thermal sensation,thermal acceptability,and normalized high and low frequency values were collected and compared The results indicated that the subjective responses of northern and southern participants were not significantly different;however,the subjective physiological symptoms and self-reported discomfort of the latter were less than those of the former,indicating that the southern participants had superior heat tolerance.Additionally,the physiological responses of all the participants were largely similar.However,southern participants showed slightly higher normalized high frequency and BVP values,indicating that they have more active vagus nerves and better vasodilation.They also showed a wider acceptable temperature range and better acclimation to heat exposure.Notably,the mean skin temperature could not effectively predict thermal sensation during heat exposure;this was more accurately achieved using the rate of change of skin temperature.These findings suggest that long-term thermal experiences can affect building occupants’thermal adaptability.

江浙沪地区城市高温脆弱性评价

以江浙沪地区25个城市为研究对象,从暴露性、敏感性和适应能力三方面构建城市高温脆弱性评价指标体系,并应用城市高温脆弱性模型和脆弱度贡献模型分析2011年—2020年江浙沪地区城市高温脆弱性变化特征及致脆类型。结果表明:10年来,70%的城市高温脆弱性呈上升趋势,其中温州市脆弱性指数逐年升高,丽水市逐年降低,镇江等7个城市高温脆弱性呈波动下降趋势,南京等16个城市呈波动上升趋势,空间上,研究区高温热脆弱性整体呈现中部偏南地区最高,向南北两个方向递减的分布特征;其中较高等级城市数量最多,主要分布于中南部地区;低等级城市数量最少,分布在研究区北部。敏感致脆型城市数量最多,其次为暴露型致脆城市,适应能力不足致脆型城市最少。

液冷背心冰水比例对人体热湿舒适性的影响

为探究液冷服进水口温度对制冷效果及人体热舒适的影响,文章采用不同比例冰水混合物(2 kg水、0.5 kg冰加1.5 kg水、1 kg冰加1 kg水)作为冷源,通过真人着装实验,测试了皮肤温度、出汗量等客观指标及主观感受,研究了高温环境下(温度为32℃和36℃、湿度为50%)液冷服的降温效果。研究结果表明,本实验条件下,32℃时冰水比例为1︰3即可满足人体热舒适需求,36℃时冰水比例需要达到1︰1;液冷服设计时应加强肩胛部位的降温。

探讨PCB曝光机定位平台精度的提升

为了减轻印制电路板(PCB)曝光机精密定位平台因直线电机发热而引起定位精度变化的问题,设计了一种定位平台直线电机散热方案用于提升散热效率,从而提升定位平台定位精度。试验测试结果表明:定位平台增加了强制风冷装置,电机的温度变化下降了48%,平台定位精度变化降低了69%。使用该散热方案,可提升直线电机的散热效果,减少电机发热对定位平台定位精度的影响,提高精密定位平台的稳定性。

长期高温对商品肉鸡和地方品种鸡肉质及风味的影响

选择体质量相近、健康的5周龄AA肉公鸡和北京油鸡公鸡各108只,评价持续高温对其胸肌肉质性状及风味物质含量的影响。试验设3个处理:34℃持续高温,自由采食(试验组,34AL);21℃适温,自由采食(适温对照组,21AL);21℃适温,采食量与34AL组相同(采食配对组,21PF)。每个品种的鸡随机分在3个处理中,分别在3个人工环境控制舱中饲养,试验至8周龄结束。结果表明:在34℃环境温度下饲养3周后,AA肉鸡胸肌L*值和滴水损失增加(P<0.05),肌苷酸含量降低(P<0.01),肌内脂肪含量明显升高(P<0.01);热暴露北京油鸡胸肌肉质性状(除pHu外)及肌内脂肪、肌苷酸含量与对照组相比无显著差异(P>0.05)。研究指出,持续34℃高温使AA肉鸡胸肌肉质有一定程度下降;而北京油鸡对高温的适应性较强,肌纤维对高温不敏感。