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1.
摘要 目的:探讨脓毒症患者血清降钙素原(PCT)、C-反应蛋白(CRP)与凝血功能、病情评分的关系及预后的影响因素。方法:选择2017年8月至2019年10月我院诊治的150例脓毒症患者作为研究对象,根据脓毒症组患者的生存状况将其分为存活组(n=118)和死亡组(n=32)。检测两组患者血清PCT、CRP水平,凝血酶原时间(PT)和部分凝血活酶时间(APTT)。采用急性生理功能和慢性健康状况评分系统Ⅱ(APACHEⅡ)和序贯器官衰竭估计(SOFA)对两组患者病情进行评估。比较两组患者临床资料。相关性分析采用Pearson检验。患者预后的影响因素采用多因素Logistic回归分析。结果:与存活组相比,死亡组血清PCT、CRP,PT、APTT,APACHE II和SOFA评分均明显升高(P<0.05)。血清PCT>7.32 ng/mL、CRP>86.73 ng/mL、PT>15.48s、APTT>36.74s、APACHE Ⅱ评分>15.88分和SOFA评分>6.48分均是脓毒症患者死亡的危险因素(OR=2.099、1.747、2.333、1.596、1.916、2.208,P<0.05)。血清PCT和CRP均与APACHE Ⅱ评分、SOFA评分、PT和APTT呈正相关(P<0.05)。结论:血清PCT和CRP水平升高与脓毒症患者死亡相关,两者与脓毒症患者APACHE Ⅱ评分、SOFA评分、PT和APTT存在正相关,并且是患者不良预后的影响因素,在脓毒症患者预后的评估中具有一定临床价值。  相似文献   

2.
摘要 目的:探讨血清可溶性血栓调节蛋白(sTM)、降钙素原(PCT)、C-反应蛋白与前白蛋白(CRP/PAB)比值与脓毒症患者急性生理和慢性健康评估Ⅱ(APACHEⅡ)评分、序贯器官衰竭评估(SOFA)评分的相关性及其联合检测对预后的预测价值。方法:选取2020年3月~2020年12月我院重症医学科收治的97例脓毒症患者,根据Sepsis-3.0诊断标准分为普通脓毒症组44例、脓毒性休克组53例,根据入院后30 d内预后情况分为死亡组35例和存活组62例。收集患者基线资料和APACHEⅡ评分、SOFA评分,并检测血清sTM、PCT、CRP/PAB比值。采用Spearman相关性分析脓毒症患者血清sTM、PCT、CRP/PAB比值与APACHEⅡ评分、SOFA评分的相关性,多因素Logistic回归分析脓毒症患者预后不良的影响因素,受试者工作特征(ROC)曲线分析血清sTM、PCT、CRP/PAB比值对脓毒症患者预后不良的预测价值。结果:脓毒性休克组血清sTM、PCT、CRP/PAB比值和APACHEⅡ评分、SOFA评分高于普通脓毒症组(P均<0.05)。Spearman相关性分析显示,脓毒症患者血清sTM、PCT、CRP/PAB比值与APACHEⅡ评分、SOFA评分呈正相关(P<0.05)。多因素Logistic回归分析显示,收缩压升高为脓毒症患者预后不良的独立保护因素(P<0.05),脓毒性休克、合并器官损伤≥3个、机械通气时间延长、APACHEⅡ评分增加、SOFA评分增加、sTM升高、PCT升高、CRP/PAB比值升高为独立危险因素(P均<0.05)。ROC曲线分析显示,血清sTM、PCT、CRP/PAB比值联合预测脓毒症患者预后不良的曲线下面积大于各指标单独预测。结论:脓毒症患者血清sTM、PCT、CRP/PAB比值升高与APACHEⅡ评分、SOFA评分增加密切相关,血清sTM、PCT、CRP/PAB比值联合检测对脓毒症患者预后不良的预测价值较高。  相似文献   

3.
摘要 目的:探究脓毒症患者发生凝血功能紊乱的临床特征及预后影响因素。方法:选择2019年9月~2023年1月本院收治的80例脓毒症患者为本次研究对象,对所有患者开展凝血功能检验,并依据检验结果,将患者分为凝血功能异常组(n=60)及正常组(n=20),分析凝血功能障碍异常及正常患者临床特征、凝血功能障碍异常及正常患者病情严重程度,并依据脓毒症患者预后,将其分为存活组(n=64)及死亡组(n=16)脓毒症患者预后的单因素与多因素Logistic回归分析。结果:凝血功能正常组及异常组平均动脉压、体温、白细胞计数(WBC)、纤维蛋白原(FIB)、凝血酶时间(TT)指标水平无较大差异(P>0.05),与凝血功能正常组比较,凝血功能异常组患者呼吸、脉率、降钙素原(PCT)、C反应蛋白(CRP)指标水平相对较高,部分凝血活酶时间(APTT)、凝血酶原时间(PT)指标水平相对较长,PLT指标水平相对较高(P<0.05);与凝血功能正常的脓毒症患者相比较,凝血功能异常患者急性肾损伤(AKI)及急性呼吸窘迫综合征(ARDS)发生率、急性生理与慢性健康评分(APACHE Ⅱ)及急性生理功能评分(SOFA)评分更高,住ICU时间均相对较长(P<0.05),机械通气及住院时间比较(P>0.05);脓毒症患者预后影响因素分析中,结果显示,年龄、体质量指数(BMI)、性别、糖尿病史、高血压病史均未对脓毒症患者预后产生较大影响(P>0.05),PT、PCT、APTT、CRP、SOFA评分及APACHE Ⅱ评分对脓毒症预后产生严重影响,死亡组患者各指标水平均高于存活组(P<0.05);将影响脓毒症患者预后的单因素予以赋值,纳入Logistic回归分析,以PCT、PT、APTT、CRP、SOFA、APACHE Ⅱ 评分为自变量,结果显示,PCT、PT、CRP、SOFA、APACHE Ⅱ 评分是影响脓毒症患者预后的独立危险因素(P<0.05)。结论:脓毒症患者发生凝血功能紊乱会对临床相关指标产生影响,从而增加疾病严重程度,依据脓毒症患者预后,研究结果显示,PT、PCT、CRP、SOFA及APACHE Ⅱ评分均会对脓毒症患者预后产生不良影响,检验上述指标水平,可为临床评估脓毒症预后提供一定参考价值。  相似文献   

4.
摘要 目的:探讨血清降钙素原(PCT)、C反应蛋白(CRP)、糖原磷酸化酶脑型(GPBB)、高迁移率族蛋白B1(HMGB1)水平与脓毒症患儿心肌损伤指标以及预后的关系。方法:选择2019年3月至2022年3月中国人民解放军联勤保障部队第九二六医院收治的271例脓毒症心肌损伤患儿(心肌损伤组)和同期收治的227例脓毒症感染性疾病但未发生心肌损伤患儿(对照组)。检测两组血清PCT、CRP、GPBB、HMGB1水平以及心肌损伤指标水平。应用Pearson相关系数分析血清PCT、CRP、GPBB、HMGB1与心肌损伤指标之间的相关性。根据心肌损伤组患儿28d的预后情况分为死亡组和存活组,脓毒症心肌损伤患儿死亡的危险因素通过多因素Logistic回归分析。结果:心肌损伤组血清PCT、肌红蛋白(Mb)、CRP、GPBB、心肌肌钙蛋白I(cTnI)、HMGB1、肌酸激酶同工酶(CK-MB)水平均高于对照组(P<0.05)。血清PCT、CRP、GPBB、HMGB1水平均与血清Mb、CK-MB、cTnI水平呈正相关(P<0.05)。死亡组脓毒症休克比例、APACHE Ⅱ评分、SOFA评分、尿素氮、血肌酐、血清PCT、CRP、GPBB、HMGB1水平高于存活组(P<0.05)。前白蛋白低于存活组(P<0.05)。多因素Logistic回归分析结果显示,高APACHE Ⅱ评分、存在脓毒症休克、高PCT、高CRP、高GPBB、高HMGB1、高cTnI是脓毒症患儿预后的危险因素(P<0.05)。结论:脓毒症心肌损伤患儿血清PCT、CRP、GPBB、HMGB1水平增高,且与预后不良以及心肌损伤指标有关。  相似文献   

5.
摘要 目的:探讨细菌性血流感染(BSI)所致脓毒症患者血清降钙素原(PCT)、载脂蛋白M(APOM)、可溶性髓系细胞触发受体-1(sTREM-1)与预后的关系。方法:选取2021年1月~2023年10月首都医科大学附属北京朝阳医院收治的细菌性BSI所致脓毒症患者185例(脓毒症组),根据28d内预后情况分为死亡组(61例)和存活组(124例),另选取同期体检健康志愿者87例(对照组)。采用电化学发光法检测血清PCT水平,酶联免疫吸附法检测血清APOM、sTREM-1水平。单因素及多因素Logistic回归模型分析影响细菌性BSI所致脓毒症患者预后的因素。受试者工作特征(ROC)曲线分析血清PCT、APOM、sTREM-1对细菌性BSI所致脓毒症患者预后的预测价值。结果:与对照组比较,脓毒症组血清PCT、sTREM-1水平升高,APOM水平降低(P<0.05)。185例细菌性BSI所致脓毒症患者28d死亡死亡率为32.97%(61/185)。与存活组比较,死亡组血清PCT、sTREM-1水平升高,APOM水平降低(P<0.05)。多因素分析结果显示:革兰阴性菌感染、脓毒性休克、中性粒细胞/淋巴细胞比值(NLR)升高、序贯器官衰竭评估(SOFA)评分增加、急性生理和慢性健康评估Ⅱ(APACHEⅡ)评分增加、血清PCT升高和sTREM-1升高为细菌性BSI所致脓毒症患者死亡的独立危险因素,血清APOM升高为独立保护因素(P<0.05)。血清PCT、APOM、sTREM-1联合检测预测细菌性BSI所致脓毒症患者死亡的曲线下面积为0.908,大于血清PCT、APOM、sTREM-1单独检测预测的0.785、0.779、0.783。结论:细菌性BSI所致脓毒症患者血清PCT、sTREM-1水平升高和APOM水平降低与预后不良的发生有关,血清PCT、APOM、sTREM-1联合检测对细菌性BSI所致脓毒症患者死亡有较高的预测价值。  相似文献   

6.
摘要 目的:探讨血清鸢尾素(Irisin)、骨硬化蛋白(SOST)、硫化氢(H2S)与膝骨关节炎(KOA)合并骨质疏松症(OP)患者骨密度、骨代谢标志物的相关性,分析Irisin、SOST、H2S预测KOA合并OP的价值。方法:选取2020年4月至2023年4月我院收治的179例KOA患者,根据是否合并OP将其分为OP组(68例)和非OP组(111例)。检测血清Irisin、SOST、H2S和骨代谢标志物骨钙素(OC)、骨碱性磷酸酶(BALP)、Ⅰ型原胶原N-端前肽(PINP)、抗酒石酸酸性磷酸酶异体(TRACP5b)水平,股骨颈、腰椎L1~4骨密度。Pearson分析血清Irisin、SOST、H2S与股骨颈、腰椎L1~4骨密度和血清骨代谢标志物的相关性,受试者工作特征(ROC)曲线分析血清Irisin、SOST、H2S对KOA合并OP的预测价值。结果:OP组血清Irisin、H2S、OC、BALP、PINP水平,股骨颈、腰椎L1~4骨密度低于非OP组(P<0.05),TRACP、SOST水平高于非OP组(P<0.05)。OP组血清Irisin、H2S水平与股骨颈、腰椎L1~4骨密度,血清OC、BALP、PINP水平呈正相关(P<0.05),与血清TRACP水平呈负相关(P<0.05);SOST水平与股骨颈、腰椎L1~4骨密度,血清OC、BALP、PINP水平呈负相关(P<0.05),与血清TRACP水平呈正相关(P<0.05)。Irisin、SOST、H2S预测KOA合并OP的曲线下面积为0.784、0.773、0.755,联合预测KOA合并OP的曲线下面积为0.908,高于单独预测。结论:KOA合并OP患者血清Irisin、H2S水平降低、SOST水平增高,低水平Irisin、H2S和高水平SOST与骨密度降低、骨代谢异常有关,可用于预测KOA合并OP患者骨代谢异常状态和骨质流失风险。  相似文献   

7.
摘要 目的:探讨血清降钙素原(PCT)、可溶性血管内皮生长因子受体1(sFIt-1)及序贯器官衰竭(sofa)评分与重症感染的相关性及预后预测价值。方法:选取我院2020年1月到2022年12月收治的60例重症感染患者作为研究对象,依照感染严重程度分为脓毒症组(n=25),重度脓毒症组(n=20)与脓毒症休克组(n=15),另选取同期来我院体检的30名健康者作为对照组。对比四组受检者PCT、sFIt-1、sofa评分水平,分析PCT、sFIt-1、sofa与重症感染的相关性。通过对60例重症感染患者的治疗结果情况分为存活组(n=36)和死亡组(n=24),对比两组患者临床一般情况和PCT、sFIt-1、sofa评分水平,并应用;logistic回归分析分析三者对重症感染的预后预测价值。结果:四组受检者PCT、sFIt-1、sofa评分水平对比差异显著,脓毒症休克组高于重度脓毒症组、脓毒症组和对照组(P<0.05);Spearman相关分析结果显示:PCT、sFIt-1、sofa评分与重症感染呈正相关(P<0.05);存活组与死亡组患者性别、年龄、感染部位、合并冠心病、糖尿病、高血压基础疾病、病原学、重症监护室(Intensive Care Unit,ICU)住院时间对比无差异(P>0.05),存活组与死亡组患者合并心功能不全、急性生理与慢性健康评分(APACHEⅡ)评分、PCT、sFIt-1、sofa评分对比差异显著(P<0.05);logistic回归分析结果表明:PCT、sFIt-1、sofa评分为重度感染预后的独立预测指标(P<0.05)。结论:PCT、sFIt-1、sofa与重症感染呈正相关,且三者水平越高患者死亡率可能越高,因此需针对PCT、sFIt-1、sofa升高的感染患者改良治疗措施,预防预后不良情况。  相似文献   

8.
摘要 目的:探讨脓毒症患儿血清淀粉样蛋白A(SAA)、降钙素原(PCT)、C反应蛋白(CRP)与预后的关系,并分析三者对脓毒症的诊断价值。方法:纳入我院于2016年8月~2020年6月期间收治的脓毒症患儿60例开展回顾性研究,作为脓毒症组,选取同期于我院进行体检的健康儿童40例作为对照组,比较两组血清SAA、PCT、CRP水平。根据脓毒症患儿1个月内的生存、死亡情况,分成生存组(n=42)、死亡组(n=18),比较两组临床资料及血清SAA、PCT、CRP水平,经COX回归模型分析脓毒症患儿死亡的危险因素。绘制受试者工作特征(ROC)曲线分析血清SAA、PCT、CRP对脓毒症的诊断价值。结果:脓毒症组血清SAA、PCT、CRP水平显著高于对照组(P<0.05)。死亡组器官障碍数量>2个、脓毒性休克患儿占比分别为55.56%、44.44%,显著高于生存组的19.05%、9.52%(P<0.05);死亡组入院后1 h内使用抗菌治疗患儿占比为38.89%,显著低于生存组的69.05%(P<0.05);死亡组血清SAA、PCT、CRP水平高于生存组(P<0.05)。COX多因素分析结果显示,器官障碍数量>2、脓毒性休克及血清SAA、PCT、CRP水平升高是脓毒症患儿死亡的危险因素(P<0.05),而入院后1 h内使用抗菌治疗是脓毒症患儿死亡风险的保护性因素(P<0.05)。血清SAA、PCT、CRP单独及三者联合诊断脓毒症的曲线下面积(AUC)分别为0.808、0.780、0.761、0.912。结论:脓毒症患儿血清SAA、PCT、CRP明显升高,三者升高均为脓毒症患儿死亡的危险因素,且对脓毒症具有一定诊断价值。  相似文献   

9.
摘要 目的:分析小剂量糖皮质激素联合持续性血液净化治疗儿童严重脓毒症的效果及安全性。方法:选择自2021年1月至2023年1月接诊的102例儿童严重脓毒症患儿作为研究对象,随机分为对照组和观察组,各51例;对照组予以经典治疗方案,观察组在对照组的基础上,予以小剂量糖皮质激素联合持续性血液净化治疗;记录两组治疗后各项信息,比较两组治疗前后外周血乳酸、中心静脉血氧饱和度(ScvO2)、血清炎症指标、PCIS评分、APACHE Ⅱ评分,观察主要并发症发生情况。结果:与对照组相比,观察组机械通气、低血压持续及入住ICU等时间较短,7 d内停升压药率较高(P<0.05);两组28 d病死率比较无差异(P>0.05);观察组治疗后乳酸、降钙素原(PCT)、肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)水平均较对照组低,ScvO2水平较对照组高(P<0.05);观察组治疗后PCIS评分较对照组高,APACHE Ⅱ评分较对照组低(P<0.05);观察组主要并发症发生率低于对照组(P<0.05)。结论:小剂量糖皮质激素联合持续性血液净化治疗有利于儿童严重脓毒症患儿病情转归,减少主要并发症发生,可能与阻断炎症反应有关,值得进一步研究应用。  相似文献   

10.
摘要 目的:研究脓毒症大鼠肝肾功能、凝血功能和炎症指标的变化及意义。方法:选取SPF级雄性SD大鼠20只,以随机数字表法将其分成实验组与假手术组,每组各10只。其中实验组通过盲肠穿刺结扎制备脓毒症大鼠模型,假手术组大鼠仅翻动盲肠,不作结扎处理。分别采集所有大鼠术后0 h、6 h、12 h、24 h时的尾静脉血3 mL,检测并比较上述时间点两组大鼠的肝肾功能、凝血功能和炎症指标水平的差异。结果:实验组术后6 h、12 h、24 h的谷丙转氨酶(ALT)、尿素氮(BUN)以及肌酐(Cr)水平均高于假手术组(P<0.05)。实验组术后24 h的活化部分凝血活酶时间(APTT)、凝血酶原时间(PT)、纤维蛋白原(FIB)水平均高于假手术组(P<0.05)。实验组大鼠术后6 h、12 h、24 h的血清白细胞计数(WBC)、白细胞介素-6(IL-6)、降钙素原(PCT)水平均高于假手术组(P<0.05)。结论:脓毒症大鼠肝肾功能存在明显的受损,凝血功能障碍明显,且机体内会释放大量的炎症因子。  相似文献   

11.
The enantioselective composition of the amphetamines is of interest, as the enantiomers show differences in their pharmacological effects and several methods for chiral separation of amphetamines have been described. Only a few methods have used whole blood as matrix and none of these separates both classic amphetamines (amphetamine and methamphetamine) and designer amphetamines (MDA, MDMA and MDEA). The aim of this study was, therefore, to develop a method for enantioselective analysis of AM, MA, MDA, MDMA, and MDEA in whole blood. The amphetamines were extracted from 0.5 g of whole blood by liquid-liquid extraction. After derivatization with R-MTPCl, the resulting diastereomers were separated by GC on a HP-5MS column and detected by SIM-MS. R-MTPCl was used as derivatization reagent because of the stability of this reagent and good separation of these analytes. Through the method, development time and temperature of the derivatization were optimized, and by admixture of 0.02% triethylamine it became possible to detect the amphetamines in adequately low concentrations as more analytes were derivatized. The method was validated and it was linear from 0.004 to 3 microg/g per enantiomer. The accuracy was within 91-115%, while the repeatability and reproducibility were < or =15% R.S.D. A method suitable for enantioselective separation and analysis of the amphetamines has been achieved, and the method was applied to analysis of whole blood samples originating from traffic and criminal cases and post mortem cases.  相似文献   

12.
Chitosan (CS) is a naturally occurring biopolymer. It has important biological properties such as biocompatibility, antifungal and antibacterial activity, wound healing ability, anticancerous property, anticholesteremic properties, and immunoenhancing effect. Recently, CS nanoparticles have been used for biomedical applications. However, due to the limited solubility of CS in water its water-soluble derivatives are preferred for the above said applications. In this work, the nanoparticles of CS and its water-soluble derivatives such as O-carboxymethyl chitosan (O-CMC) and N,O-carboxymethyl chitosan (N,O-CMC) was synthesized and characterized. In addition, cytotoxicity and antibacterial activity of the prepared nanoparticles was also evaluated for biomedical applications.  相似文献   

13.
The genes encoding the ApaLI (5′-G^TGCAC-3′), NspI (5′-RCATG^Y-3′), NspHI (5′-RCATG^Y-3′), SacI (5′-GAGCT^C-3′), SapI (5′-GCTCTTCN1^-3′, 5′-^N4GAAGAGC-3′) and ScaI (5′-AGT^ACT-3′) restriction-modification systems have been cloned in E.␣coli. Amino acid sequence comparison of M.ApaLI, M.NspI, M.NspHI, and M.SacI with known methylases indicated that they contain the ten conserved motifs characteristic of C5 cytosine methylases. NspI and NspHI restriction-modification systems are highly homologous in amino acid sequence. The C-termini of the NspI and NlaIII (5′-CATG-3′) restriction endonucleases share significant similarity. 5mC modification of the internal C in a SacI site renders it resistant to SacI digestion. External 5mC modification of a SacI site has no effect on SacI digestion. N4mC modification of the second base in the sequence 5′-GCTCTTC-3′ blocks SapI digestion. N4mC modification of the other cytosines in the SapI site does not affect SapI digestion. N4mC modification of ScaI site blocks ScaI digetion. A DNA invertase homolog was found adjacent to the ApaLI restriction-modification system. A DNA transposase subunit homolog was found upstream of the SapI restriction endonuclease gene. Received: 15 April 1998 / Accepted: 3 August 1998  相似文献   

14.
The two malonylated pigments, malonylmalvin and malvidin 3-malonylglucoside, were identified in petals of Lavatera maritima, which belongs to the Malvaceae, a family known to synthesise such pigments. Zwitterionic anthocyanins could not be detected in four other newly examined sources and common unacylated pigments were recorded. Thus, the fruits of the palms Euterpe edulis and Pinanga polymorpha have a mixture of cyanidin 3-glucoside and cyanidin 3-rutinoside, while the fruit of Cephaelis subcoriacea is coloured by cyanidin 3-glucoside. The latter pigment was also obtained from the reddish brown inflorescence of the parasitic plant Cynomorium coccineum.  相似文献   

15.
Two isomers (R,S,R,S- and R,R,S,S-) of five coordinate complex [Cu(L)Cl]+ have been separated and characterised. These two isomers have significantly different spectrochemical and electrochemical properties. Absorption maximum of R,S,R,S-[Cu(L)Cl]+ shifts to longer wavelength and its reduction potential shifts to more positive direction comparing those of R,R,S,S-[Cu(L)Cl]+. R,S,R,S-[Cu(L)Cl]+ is significantly distorted to trigonal-bipyramidal structure, whereas R,R,S,S-[Cu(L)Cl]+ retains almost square-planar geometry. The average bond distance of Cu-N in basal plane of R,S,R,S-[Cu(L)Cl]+ is longer by 0.024 Å than that of R,R,S,S-[Cu(L)Cl]+, whereas the bond distance of Cu-Cl in former is shorter by 0.200 Å than that in latter. The isolated square-planar complexes of R,R,S,S- and R,S,R,S-[Cu(L)](ClO4)2 are converted to the R,R,S,S- and R,S,R,S-[Cu(L)Cl]+ by the addition of Cl in nitromethane solution with the rate constants, k=1.70 (±0.02) and 8.31 (±0.07) M−1 s−1, respectively.  相似文献   

16.
The reactions of [ReCl22-N2C(O)Ph}(PPh3)2] (1) with 2-aminopyrimidine (H2Npyrm), 2,2′-bipyridine (bpy) and tetraethylthiuram disulfide (tds), in MeOH upon reflux, lead to the new η1-(benzoyldiazenido)rhenium(III) complexes [ReCl{η1-N2C(O)Ph}(HNpyrm)(PPh3)2] (2) and [ReCl21-N2C(O)Ph}(bpy)(PPh3)] (3), and the known oxo(diethyldithiocarbamato)dirhenium(v) complex [Re2O2(μ-O){Et2NC(S)S}4] (4), respectively. The Et2NC(S)S ligands in 4 result from S-S bond rupture of tds molecules. The obtained compounds have been characterized by IR, 1H, 31P{1H} and 13C{1H} NMR spectroscopies, FAB+-MS, elemental and single-crystal X-ray diffraction (for 2 and 4) analyses. Complex 2 represents the first structurally characterized Re compound derived from 2-aminopyrimidine. Besides, the redox behaviour of 2-4 in CH2Cl2 solution has been studied by cyclic voltammetry, and the Lever electrochemical ligand parameter (EL) has been estimated, for the first time, for HNpyrm. The electrochemical results are discussed in terms of electronic properties of the Re centres and the ligands.  相似文献   

17.
This paper presents the advances made over the last decade in cryopreservation of economically important vegetatively propagated fruit trees. Cryopreservation protocols have been established using both dormant buds sampled on field-grown plants and shoot tips sampled on in vitro plantlets. In the case of dormant buds, scions are partially dehydrated by storage at − 5 °C, and then cooled slowly to − 30 °C using low cooling rates (c.a. 1 °C/h) before immersion in liquid nitrogen. After slow rewarming and rehydration of samples, regrowth takes place either through grafting of buds on rootstocks or excision of apices and inoculation in vitro. In the case of shoot tips of in vitro plantlets, the cryopreservation techniques employed are the following: controlled rate cooling procedures involving slow prefreezing followed by immersion in liquid nitrogen or vitrification-based procedures including encapsulation–dehydration, vitrification, encapsulation–vitrification and droplet-vitrification. The current status of cryopreservation for a series of fruit tree species including Actinidia, Diospyros, Malus, Olea, Prunus, Pyrus and Vitis is presented. Routine application of cryopreservation for long-term germplasm storage in genebanks is currently limited to apple and pear, for which large cryopreserved collections have been established at NCGRP, Fort Collins (USA), using dormant buds and in vitro shoot tips, respectively. However, there are a growing number of examples of pilot scale testing experiments under way for different species in various countries. Progress in the further development and application of cryopreservation techniques will be made through a better understanding of the mechanisms involved in the induction of tolerance to dehydration and cryopreservation in frozen explants.  相似文献   

18.
Seven species from five genera of Annonaceae were studied with regard to their flower biology and pollination in the Southwest Province of Cameroon, West Africa. They have protogynous hermaphroditic flowers, with exception of Uvariopsis species, which are monoecious. Fused petals of Isolona campanulata remain apically spreading and open during anthesis but form a deep basal urceolate tube around the reproductive organs. At anthesis the yellow pendent flowers emit a fruit-like scent and attracted small beetles, the likely pollinators. Piptostigma sp. flowers also emit a fruit-like scent but provide a closed pollination chamber formed by the three inner petals. Small staphylinid beetles attracted during the female stage of anthesis are released from the flowers at the end of the male stage 2-3 days later. Both species have diurnal anthesis, attracting and releasing the flower visitors during daytime. In contrast, Uvariodendron connivens and U. calophyllum have nocturnal anthesis with floral thermogenesis, produce spicy, aromatic and fruity scents and attract large Scarabaeidae beetles, the pollinators, along with many curculionid beetles, which were principally predators of the thick petals. The very large flowers of Monodora tenuifolia have yellowish petals which are spotted with dark red markings. Together with the sweetish, slightly disagreeable scent the flowers attract flies, principally dung flies. The two investigated Uvariopsis species are monoecious with pistillate and staminate flowers being functional at the same time. The violet red flowers of U. bakeriana visually seem to mimic the fruiting body of certain stinkhorn fungi (Phallaceae) although without producing their strong unpleasant carcass stench. Flower-visiting dung flies were rare. Conversely, U. congolana has a strong fungus-like scent, its flowers are presented at litter height and dung flies living in the litter were the flower visitors, albeit sporadic. The 4-5 days lasting anthesis of both Uvariopsis species appears to be an evolutionary consequence of their diffuse pollinator spectra. The studied African Annonaceae therefore have either cantharophilous or myiophilous/sapromyiophilous flowers with, in part, respectively, remarkably long anthesis, thermogenesis, and widely open, large flowers - all attributes unknown or rare in the hitherto better studied Neotropical Annonaceae.  相似文献   

19.
Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.  相似文献   

20.
The present work investigates some probiotic properties of four different microorganisms (Bifidobacterium animalis var. lactis BB-12, Escherichia coli EMO, Lactobacillus casei and Saccharomyces boulardii). In vitro and in vivo tests were carried out to compare cell wall hydrophobicity, production of antagonistic substances, survival capacity in the gastrointestinal tract of germ-free mice without pathological consequence, and immune modulation by stimulation of Küpffer cells, intestinal sIgA and IL-10 levels. In vitro antagonism against pathogenic bacteria and yeast was only observed for the probiotic bacteria B. animalis and L. casei. The hydrophobic property of the cell wall was higher for B. animalis and E. coli EMO, and this property could be responsible for a better ability to colonize the gastrointestinal tract of germ-free mice. Higher levels of sIgA were observed mainly for S. boulardii, followed by E. coli EMO and B. animalis, and only S. boulardii induced a significant higher level of IL-10. In conclusion, for a probiotic use, S. boulardii presented better characteristics in terms of immunomodulation, and B. animalis and L. casei for antagonistic substance production. The knowledge of the different probiotic properties could be used to choice the better microorganism depending on the therapeutic or prophylactic application.  相似文献   

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