DIA-based quantitative proteomic analysis on porcine meat quality at different chilling rates

The objective of this study was to evaluate the effects of chilling rate on porcine meat quality from the perspective of proteome using data independent acquisition(DIA)-based quantitative proteomic strategy. M. longissimus thoracis et lumborum(n = 9) was assigned randomly to the control group(3.72 ℃/h), very fast chilling-Ⅰ group(VFC-Ⅰ, 9.31℃/h) and VFC-Ⅱ group(14.43 ℃/h). The DIA was used to analyze the difference in proteins under different chilling rates. Results showed that tenderness was improved significantly in meat at the chilling rate of 14.43 ℃/h. Seventy-nine differential abundant proteins(fold change > 1.5, P < 0.05), including 46 up-regulated and 33 down-regulated proteins, were identified and mainly involved in carbon metabolism, pyruvate metabolism and proteasome pathways. These pathways indicated that VFC delayed cell metabolism and glycolysis by down-regulating the expression of metabolic enzymes. The tenderness was improved by up-regulating the expression of proteasome and m-calpain.

Smart Colorimetric Corn Starch Films Combined with Anthocyanin-Loaded Glutenin-Carboxymethyl Chitosan Nanocomplexes for Freshness Monitoring of Chilled Pork

In this study,intelligent,pH-responsive colorimetric films were prepared by encapsulating anthocyanins in nanocomplexes prepared from glutenin and carboxymethyl chitosan.These nanocomplexes were added to a corn starch matrix and used in the freshness monitoring of chilled pork.The effects of anthocyanin-loaded nanocomplexes on the physical,structural,and functional characteristics of the films were investigated.The addition of anthocyanin-loaded nanocomplexes increased the tensile strength,elongation at break,hydrophobicity,and light transmittance of the films while decreasing their water vapor permeability.This is because new hydrogen bonds are formed between the film components,resulting in a more homogeneous and dense structure.The colorimetric film has a significant color response to pH changes.These films were used in experiments on the freshness of chilled pork,in which the pH changes with changing freshness states.The results show that the colorimetric film can monitor changes in the freshness of chilled pork in real time,where orange,pink,and green represent the fresh,secondary fresh,and putrefied states of pork,respectively.Therefore,the intelligent colorimetric film developed in this study has good application potential in the food industry.

Temperature Trends and Accumulation of Chill Hours, Chill Units, and Chill Portions in South Carolina

There is considerable concern about the potential impact of climate change on agriculture, such as the accumulation of chilling hours needed to break the dormancy of many perennial plants, like fruit trees. Therefore, this study aimed to determine if there had been a significant change in air temperatures and chill hours, chill units, and chill portion accumulation in South Carolina over the last two decades. Two decades of daily maximum (Tmax) and minimum (Tmin) air temperature records were obtained from weather stations in thirty-one counties in South Carolina. Hourly temperature data, reconstructed from the daily data, were used to calculate the daily and annual chill hours, chill units, and chill portions accumulation using four different chill models for each location and year. The chill models included the T(t) °C model, the 0°C °C model, the Utah model, and the Dynamic model. For each county, regression analyses were conducted to evaluate the historical trends. Despite year-to-year variability, the tendency was a statistically significant (α = 0.05) increase in air temperature, averaging 0.089°C per year for 20 out of 31 counties in South Carolina. The other 11 counties had no significant change in temperature. The average temperature increase in the 31 counties was 0.072°C per year. The temperature increase resulted in a decrease in annual chill accumulation during the fall to spring, averaging 17.7 chill hours, 8.6 chill hours, 17.0 chill units, and 0.40 chill portions per year calculated with the T(t) °C, 0°C °C, Utah, and Dynamic models, respectively. However, whether this decrease in chill values was statistically significant or not depended on the chill model used. This study did not investigate the cause of the observed historical trends in temperature and chill accumulation. Still, if the trends continue, they could significantly impact the future of the temperate fruit tree industry in the state.

Exogenous melatonin improves the chilling tolerance and preharvest fruit shelf life in eggplant by affecting ROS-and senescence-related processes

Low temperature is the most common abiotic stress factors during the eggplant cultivation in solar greenhouses.Melatonin plays important roles in plant resistance to low temperature.However,the role of melatonin in regulating chilling tolerance and extending the preharvest shelf life of eggplant fruits is still unknown.In this study,we investigated the effects of exogenous melatonin on eggplant plants and fruits in response to low temperature.Under simulated low-temperature conditions,exogenous melatonin significantly relieved the chilling symptoms of seedlings by reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels and relative leakage rates.These reductions were caused by higher superoxide dismutase (SOD) and catalase (CAT) activities and increased endogenous polyamine and melatonin levels compared with those in untreated seedlings.Notably,the expression levels of SOD,CAT1/2,and polyamine synthesis genes (ADC and ODC) were also increased by 100μmol·L~(-1)melatonin,as well as those of genes involved in melatonin synthesis (TDC,T5H,SNAT,ASMT,and COMT) and cold regulation (COR1,CBFa/b,and ZAT2/6/12).To further investigate the effects of melatonin on eggplant leaves and fruits under natural low temperature conditions,100μmol·L~(-1)melatonin was sprayed on the functional leaves at three days before commodity maturation.Melatonin significantly alleviated chilling injury in the leaves and pericarp and extended the preharvest shelf life of the fruit by increasing the expression of COR1,CBF,ZAT2/6/12,and API5 and decreasing the expression of senescence-related genes (NCED1/2 and SAG12).Therefore,100μmol·L~(-1)melatonin improved chilling tolerance and fruit shelf life by upregulating ZAT2/6/12 to affect ROS-and senescence-related processes,which provides a reference for alleviating cold stress and extending the preharvest fruit shelf life in eggplant.

Genome-wide profiling of histone H3 lysine 27 trimethylation and its modification in response to chilling stress in grapevine leaves

Histone H3 lysine 27 trimethylation(H3K27me3) is a histone modification associated with transcriptional repression. However, insights into the genome-wide pattern of H3K27me3 in grapevines are limited. Here, anti-H3K27 chromatin immunoprecipitation(ChIP), high-throughput sequencing, and transcriptome analysis were performed using leaves of Vitis amurensis. The leaves were treated at 4°C for 2 h and 24 h and used to investigate changes in H3K27me3 under chilling treatment. The results show that H3K27me3 is well-distributed both in gene regions(-50%) and in the intergenic region(-50%) in the grapevine genome(Vitis vinifera ‘Pinot Noir PN40024'). H3K27me3 was found to be localized in8 368 annotated gene regions in all detected samples(leaves at normal temperature and under chilling treatments) and mainly enriched in gene bodies with the adjacent promoter and downstream areas. The short-term chilling treatments(4°C for 2 h) induced 2 793 gains and 305losses in H3K27me3 modification. Subsequently, 97.3% of the alterations were restored to original levels after 24 h treatment. The ChIP-qPCR for five differential peaks showed similar results to the data for ChIP-seq, indicating that the chilling-induced H3K27me3 modification is reliable.Integrative analysis of transcriptome and ChIP-seq results showed that the expression of H3K27me3 target genes was significantly lower than those of non-target genes, indicating transcriptional repression of H3K27me3 in grapevine leaves. Furthermore, histone methylation alterations were detected in 82 genes and were related to either repression or activation of their expression during chilling stress. The findings provide the genome-wide H3K27me3 patterns in grapevines and shed light on uncovering its regulation in chilling stress responses.

Melatonin treatment alleviates chilling injury in mango fruit 'Keitt' by modulating proline metabolism under chilling stress

Mangoes often suffer from low temperature-induced chilling injury (CI) during postharvest cold storage.Therefore,advanced techniques are crucial and in high demand to solve the chilling stress of mango fruit for a higher value.This study addresses chilling stress modulation by investigating the effects of melatonin treatment on CI,proline metabolism,and related gene expressions of ‘Keitt’ mango during cold storage after dipped in 0 (control),0.1 (MT1),and 0.2 mmol L^(-1)(MT2) melatonin solution for 30 min.The results revealed that melatonin treatment in MT1 significantly reduced CI development and increased proline content in mango fruit during cold storage compared to the control.These changes were along with increases in the activity of critical enzymes as well as the expression of encoding genes involved in proline biosynthesis,such as pyrroline-5-carboxylate synthetase (P5CS),pyrroline-5-carboxylate reductase (P5CR),ornithine D-aminotransferase (OAT),P5CS2,P5CR2,and OAT3.Additionally,proline dehydrogenase (PDH) activity and the expression of the PDH3 gene associated with proline dehydrogenation were lower in MT1-treated mangoes than the controlled group.Thus,melatonin treatment has regulated proline metabolism resulting in the accumulation of proline,subsequently contributing to enhancing the chilling tolerance of‘Keitt’mango fruit.

Down-regulation of MeMYB2 leads to anthocyanin accumulation and increases chilling tolerance in cassava(Manihot esculenta Crantz)

Chilling-induced accumulation of reactive oxygen species(ROS) is harmful to plants,which usually produce anthocyanins to scavenge ROS as protection from chilling stress.As a tropical crop,cassava is hypersensitive to chilling,but the biochemical basis of this hypersensitivity remains unclear.We previously generated Me MYB2-RNAi transgenic cassava with increased chilling tolerance.Here we report that Me MYB2-RNAi transgenic cassava accumulated less ROS but more cyanidin-3-O-glucoside than the wild type under early chilling stress.Under this stress,the anthocyanin biosynthesis pathway was more active in Me MYB2-RNAi lines than in the wild type,and several genes involved in the pathway,including Me TT8,were up-regulated by Me MYB2-RNAi in the transgenic cassava.Me MYB2 bound to the Me TT8 promoter and blocked its expression under both normal and chilling conditions,thereby inhibiting anthocyanin accumulation.Me TT8 was shown to bind to the promoter of Dihydroflavonol 4-reductase(Me DFR-2)and increased Me DFR-2 expression.Me MYB2 appears to act as an inhibitor of chilling-induced anthocyanin accumulation during the rapid response of cassava to chilling stress.

不同包装方式对冷鲜猪肉品质及假单胞菌生长的影响

【目的】探索冷鲜猪肉贮藏期间品质劣变情况及假单胞菌生长状况,为冷鲜肉贮藏期品质判断提供依据。【方法】采用真空、保鲜盒和热收缩膜3种方式包装冷鲜猪肉,检测4℃下贮藏第0、2、4、6、8天时肉样中假单胞菌菌落数及细菌菌落总数、感官指标、pH值、色差、水分活度值、TVB-N值的变化。【结果】相对于保鲜盒包装,真空包装和热收缩膜包装均能抑制冷鲜猪肉中菌落总数及假单胞菌菌落数增长;贮藏第4天,保鲜盒组肉样的菌落总数达到6.99 lg(CFU·g-1),真空包装组第6天才达到6.46 lg(CFU·g-1);贮藏第6天,保鲜盒组肉样中假单胞菌数最高达到7.58 lg(CFU·g-1),真空包装组和热收缩膜组分别达到了5.00 lg(CFU·g-1)、6.27 lg(CFU·g-1),显著低于保鲜盒组;贮藏期间,3组肉样的TVB-N值均呈现出上升的趋势,保鲜盒组第6天TVB-N值达到158.7 mg·kg-1,真空包装组和热收缩膜组在贮藏第8天时超过150 mg·kg-1;水分活度测定中,第4天真空包装组和热收缩膜包装组AW值大于保鲜盒包装组,贮藏第6天起,各组肉样的水分活度趋于稳定差异不显著(p>0.05);贮藏前2 d,保鲜盒组肉样L*值较高,而贮藏后期,热收缩膜组和真空包装组能维持较高的L*值;保鲜盒组肉样的a*值均整体先上升后下降趋势,热收缩膜组和真空包装组呈下降趋势,真空包装能较好延缓a*值下降;第8天,保鲜盒组肉样pH值最高,已接近7.0,热收缩膜组与真空包装组肉样pH值差异不显著(p>0.05),且均低于6。在反映肉质新鲜度上,猪肉的感官与a*值、pH值、AW值、TVB-N值、假单胞菌数相关性比较大。【结论】真空包装可以能抑制冷鲜猪肉细菌的增长、延缓TVB-N值的增长,在短期内能更好维护冷鲜猪肉的品质。

PI3K/AKT信号通路对冷却滩羊肉贮藏期间细胞凋亡的影响

以滩羊后腿肉为研究对象,采用10μmol/L磷脂酰肌醇3激酶(phosphoinositide 3-kinase,PI3K)抑制剂LY294002溶液对滩羊肉进行注射处理,4℃条件下分别贮藏0、2、4、6、8 d,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和蛋白质免疫印迹分析PI3K、蛋白激酶B(protein kinase B,AKT)蛋白的表达情况,以此验证PI3K/AKT信号通路抑制的有效性,同时分析滩羊肉贮藏期间能量因子、氧化应激水平、线粒体损伤程度以及胱天蛋白酶(cysteine aspastic acid-specific protease,Caspase)-3活性的变化,以探索PI3K/AKT信号通路对冷却滩羊肉贮藏期间细胞凋亡途径的诱导机制。结果表明,PI3K和AKT蛋白表达量均减少,验证了PI3K/AKT信号通路被抑制的有效性。与对照组相比,LY294002处理组线粒体ATP、糖原含量、琥珀酸脱氢酶和柠檬酸合成酶活性显著下降(P<0.05);线粒体活性氧(reactive oxygen species,ROS)逐渐增多,氧化应激水平和线粒体膜通透性转换孔(mitochondrial permeability transition pore,MPTP)开放程度增加;膜电位显著下降(P<0.05);凋亡因子Caspase-3活性显著升高(P<0.05),表明PI3K/AKT信号通路通过促进ROS产生并与PI3K相互作用,介导了下游Caspase-3的活化,使线粒体结构与功能受损,导致MPTP开放、膜电位降低,进而诱发细胞凋亡。

菠萝抗寒研究进展

低温是限制菠萝产量和品质的重要因素之一。我国菠萝种植适宜区冬季周期性地受到低温等自然灾害影响,且近年来频繁遭遇严峻气候环境挑战,造成减产或失收,严重影响菠萝产业可持续发展。目前,关于菠萝抗寒性研究主要集中于抗寒种质资源鉴定与评价、抗寒性评价方法、生理生化测定、抗寒基因挖掘和抗寒防治措施等方面,而在菠萝抗寒性分子机制方面的研究进展较缓慢,本文针对这些方面进行概述,以期为菠萝抗寒性状的遗传改良及生产上防寒防冻提供参考。

2018-2023年北京市注射用曲妥珠单抗不良反应统计分析

目的为注射用曲妥珠单抗的临床安全应用提供依据。方法收集北京市2018年6月至2023年5月上报的注射用曲妥珠单抗相关的药品不良反应(ADR)报告,运用SPSS 25.0软件进行统计,分析出现ADR的患者性别、年龄、转归情况、所患癌症种类和ADR发生时间、严重程度、累及器官/系统等,并对患者发热及ADR预后情况进行单因素Logistic回归分析。结果共有195例患者累计318例次ADR纳入研究。女性(87.69%)和60~69岁年龄段(33.85%)患者出现ADR的情况较多;在癌症种类分布上,乳腺癌占据主导位置(86.67%);从转归情况来看,大多数患者(67.69%)表现出好转,部分患者(27.69%)实现痊愈。68.72%的ADR主要在用药当天出现,95.38%的ADR严重程度为“一般”。出现ADR最多的器官/系统是全身性疾病及给药部位各种反应(40.57%),以寒战(18.87%)和发热(18.24%)最为常见。单因素Logistic回归分析结果显示,发热多出现在用药后1 d内(OR=5.63,95%CI为2.26~14.02,P<0.001);ADR发生时间≥1 d是ADR预后差的危险因素(OR=20.08,95%CI为2.45~164.43,P=0.005),多表现为骨髓抑制和肝功能异常。粒细胞增多症、心脏呼吸骤停和混合性肝损伤为该药说明书未记录的新的ADR。结论女性和≥60岁患者为注射用曲妥珠单抗ADR的高发人群;寒战和发热是该药最常见的ADR,且多在用药后1 d内出现,但预后较好。在输注该药当天应密切关注患者的体温变化,适时干预;用药后应定期监测患者的血液学指标,关注其是否存在骨髓抑制和肝功能异常。

基于作物模型与机器学习的水稻障碍型冷害脆弱性研究

以水稻障碍型冷害为例,提出一种突破数据限制并兼顾承灾体反应机理的新方法,构建农业气象灾害脆弱性曲线。基于1990-2010年气象数据设计水稻抽穗开花期的障碍型冷害情景,通过MCWLA-Rice作物模型和机器学习混合建模法计算对应的水稻单产损失,最终建立不同水稻主产区的障碍型冷害脆弱性曲线,并对1961-2010年水稻障碍型冷害单产损失快速评估。结果表明:(1)机器学习可有效重现作物模型模拟精度(RRMSE<6%,R^(2)>0.93)。(2)水稻障碍型冷害脆弱性具有明显的空间和种植制度差异,高纬地区到低纬地区水稻脆弱性整体呈下降趋势,且晚稻脆弱性普遍低于早稻。(3)一季稻抽穗开花期障碍型冷害的年均单产损失(1224kg·hm^(−2))高于双季稻(早稻:868kg·hm^(−2);晚稻:807kg·hm^(−2))。

上海地区梨品种需冷量及需热量研究

以上海地区4个梨品种为研究对象,采用不同模型测试其需冷量及需热量。结果表明:梨品种的需冷量在≤7.2℃模型下为191—518 h、0—7.2℃模型下为171—394 h、犹他模型下为138—192 C·U(‘翠冠’除外),‘翠冠’需冷量最低,其次为‘沪晶梨18号’和‘沪晶梨67号’,需冷量最高的是‘早生新水’;需热量在生长度小时模型下为10456—10781 GDH·℃,‘早生新水’需热量最低,其次为‘翠冠’,需热量最高的为‘沪晶梨18号’和‘沪晶梨67号’;有效积温模型为187—240 D·℃,‘翠冠’的需热量最低,其他品种间无明显差异。上海地区的梨品种的需冷量估算,优先推荐使用0—7.2℃模型,犹他模型更适用于需冷量高的梨品种,生长度小时模型比有效积温模型更适合梨需热量估算。

湿热地区室内气流调控对人群健康的影响

气流调控在改善湿热地区夏季热环境质量方面发挥着关键作用。然而,多数研究主要关注气流对人体全身热舒适的积极作用,而忽略了气流作用于身体局部时对人体健康的潜在影响。本研究采用随机抽样方法,于2023年8—10月在广东省21个地级市开展了问卷调研,共收集1 349份有效问卷。统计分析结果显示:当气流温度过低或气流主要作用于人体额头、腹部、太阳穴等敏感部位时,最易引发头疼、流涕、面瘫等症状;在年龄与性别差异上,青年人群相较于其他年龄段人群更容易因气流影响而出现此类症状,女性相比男性更排斥被气流直吹身体。这些发现可为制定湿热地区不同人群的健康气流调控策略提供支撑,有利于提升城市居民的生活质量和健康水平。

外源绿原酸对番茄幼苗低温耐性的生理调控效应

【目的】番茄苗期常遭遇低温冷害,严重影响花果正常发育。酚酸物质绿原酸是农作物抗逆响应的关键代谢物质,但外源绿原酸是否能增强作物耐冷性尚不明确。因此,以低温耐性不同的两个番茄品种为材料,研究外源根施绿原酸对番茄低温耐性的调控效应及可能机制。【方法】以番茄(Solunum lycopersacum)强耐低温品种京番401(JF401)和弱耐低温品种京番101(JF101)为试验材料开展室内盆栽试验。基于前期试验获得的参数,设置6个绿原酸(CGA)根施浓度处理:0、0.005、0.025、0.05、0.1和0.25 g/L。根施CGA后,番茄幼苗在正常温度下生长5周,然后在低温(昼夜温15℃/5℃)胁迫下生长6天。在低温胁迫结束后2天,用手持式叶绿素荧光仪测定完全展开叶片初始荧光产量(Fo)、最大荧光产量(Fm),光化学猝灭系数(Qp)、非光化学猝灭系数(NPQ)及PSII实际光化学效率(ФPSII);调查番茄幼苗地上部鲜重(SFW)、根系鲜重(RFW)和总鲜重(TFW);测定完全展开叶片相对电导率(REC)、叶绿体色素含量(Chl.a、Chl.b、Car)、自由水含量(LFW)和束缚水含量(LBW);测定叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、过氧化氢(H_(2)O_(2))和丙二醛(MDA)含量。【结果】在供试CGA浓度范围内,JF401和JF101番茄幼苗的耐冷性均随CGA浓度的升高先增加后降低,最高耐冷性综合评价指标D值分别出现在0.1和0.05 g/L。Pearson相关分析表明,D值与Fv/Fm、Qp、ФPSII、Chl.a、Chl.(a+b)、SFW、RFW、TFW、SOD、POD、CAT和LBW显著正相关(R=0.72~0.98),与H_(2)O_(2)、NPQ、REC、MDA和LFW显著负相关(R=0.63~0.98)。PCA主成分分析表明,SFW、Chl.b、Chl.(a+b)、Qp、ФPSII和LBW是影响两品种番茄苗期低温耐性的共性关键指标。在CGA最佳浓度下,京番101幼苗的ФPSII、Chl.(a+b)、LBW和SFW较CK的增幅分别为157.7%、35.5%、8.4%和24%,京番401幼苗的增幅分别为223.5%、64.9%、31.2%和62%。【结论】低温胁迫下,根施适量绿原酸可通过改善光能吸收及利用、降低水分生理代谢、增强酶促抗氧化防御和清除活性氧等多途径调控机制,显著提升番茄幼苗低温耐性。

甜橙精油-北五味子提取物复合膜的制备及其在冷鲜猪肉保鲜中的应用

为提高冷鲜猪肉的保鲜能力并延长其货架期,以甜橙精油(orange essential oil,OEO)、北五味子提取物(Schisandra chinensis extract,SCE)为活性成分,羧甲基纤维素钠(sodium carboxymethyl cellulose,CMC-Na)为成膜基质,采用流延法制备复合膜。利用单因素试验和正交试验优选复合膜的配制方法,以色泽、汁液流失率、pH值、感官评价、总挥发性盐基氮含量和菌落总数探究OEO-SCE复合膜对冷鲜猪肉保鲜能力的影响。结果表明,当CMC-Na添加量为1.0 g/100 mL、SCE添加量为0.9 g/100 mL、OEO添加量为0.2%(V/V)时,制备的复合膜综合性能最佳:断裂伸长率为(63.860±0.120)%,抗拉强度为(8.800±0.049)MPa,水蒸气透过率为(2.360±0.070)g·mm/(m^(2)·h·kPa)。用该膜包裹冷鲜猪肉进行保鲜,与未包膜组相比,色泽及感官评分有明显提升,可以有效降低贮藏期内的总挥发性盐基氮含量、pH值、汁液流失率及菌落总数,贮藏期从6 d延长至8 d。由此可见,OEO-SCE复合膜可以抑制冷鲜猪肉在贮藏期内的腐败变质并延长其贮藏期。

采后黄瓜在冷驯化处理过程中的转录组变化

采后黄瓜是冷敏性果菜类蔬菜,在低温贮藏时易发生冷害。前期研究结果表明,冷驯化处理通过诱导采后黄瓜耐冷性,减少冷害发生。为探究冷驯化处理诱导的转录组学变化,以采后黄瓜为试材,分析冷驯化处理期间的转录组变化。与贮藏前(0 h)相比,在冷驯化处理12 h和72 h时,分别鉴定到1 870和3 550个差异表达基因。基因表达验证结果表明,RT-qPCR和转录组结果高度一致,证明转录组测序数据的准确性和可靠性。GO富集分析结果显示,冷驯化处理诱导的差异表达基因主要富集在氧化还原过程、细胞膜组分和转录因子活性3个GO途径中,表明冷驯化处理通过调节细胞膜组分、细胞内氧化还原状态,增强冷藏黄瓜耐冷性。进一步分析发现,104个转录因子基因响应冷驯化低温,差异表达的转录因子主要是ERF、bZIP、WRKY和HSF家族,表明转录因子介导的转录调控在冷驯化诱导的耐冷性中发挥重要作用。研究结果为采后黄瓜诱导耐冷性提供了新见解,有助于加深对冷驯化诱导耐冷性分子机理的认识,为耐冷黄瓜培育提供了重要基因资源。

中国主要城市气候舒适度时空特征

人居气候舒适性是评判城市环境宜居水平的重要因素之一。利用1991-2020年中国31个主要城市的每日气象要素资料,采用室外天气舒适指数(OWCI)模型,分析了中国主要城市人居气候舒适性总体水平、舒适度年内变化类型、冬夏两季的空间差异,并剖析了城市的夏季炎热特征及其变化趋势。结果表明,中国大多数城市年平均气候舒适度高于舒适等级水平,但空间差异明显,31个主要城市一年中舒适天气累计日数均超过半年,年平均舒适日数为231天,总体人居气候环境良好。中国31个主要城市气候舒适性年内变化可分为寒冬凉夏型、冷冬凉夏型、冷冬热夏型、暖冬长夏型及四季舒适型5种类型;春秋季节天气普遍舒适,冬夏两季气候舒适性空间差异很大,冬季的差异大于夏季的,12座城市适合夏季避暑,比较适合冬季避寒的城市有海口、广州、昆明、南宁和福州。夏季酷热的城市主要分布于长江中下游流域,近30年其夏季的酷热日数和酷热程度有较明显的增加趋势。

世界及中国蓝莓产业现状

概述了世界蓝莓及中国蓝莓产业情况,笔者从蓝莓栽培面积、产量、品种等几个方面做了阐述,分析了中国蓝莓产业的发展前景,旨在提供产业信息,促进产业发展。

中镍无限冷硬球墨铸铁轧辊辊颈缺陷原因分析及应用

分析了中镍无限冷硬球墨铸铁轧辊离心铸造时产生气孔、夹渣的工艺原因,采取了预脱氧处理、控制稀土镁球化剂使用率、提高浇注速度、提高型砂透气性、控制混合保护渣使用量、配箱时间控制在3 min以内等措施,辊颈气孔和夹渣产生的废品率从40%降低到6%以内,有效降低了废品率。