An experimentally supported, mathematical explanation of the gas chromatographic elution behaviour of the long-chain carbon members of the homologous series

By substituting the saturated vapour phase tension of the pure normal hydrocarbons described by the Clausius-Clapeyron law into the accepted expression of the specific retention volume (V_g,T), a theoretically coherent and relatively simple mathematical evidence of the elution behaviour of the homologous members has been deduced. It gives exponential retention time dependence on carbon number for isothermal, and nearly equidistant (i.e., approximately linear retention-time dependence on carbon number) elution for linear temperature programmed gas chromatographic runs. The final equations are in close correlation with the experimental results. Special emphasis is placed on the fact that a good approximation—not strict physical laws—have been found.     

充气温控毯用于神经外科手术患者的控温效果

目的评价充气温控毯用于神经外科手术患者的控温效果。方法40例择期行平卧位脑肿瘤切除术患者,年龄16—65岁,体重41-72 kg,ASAⅠ-Ⅲ级,随机分为2组(n=20):A组,术中充气温控毯24℃风档进行降温,肿瘤切除完毕前30 min进行复温;B组,术中充气温控毯维持中心温度正常(35．2—36．60℃)。均采用气管内静吸复合麻醉,静脉注射异丙酚1．5～2 mg／kg、芬太尼4-6μg／kg、维库溴铵0．1～0．2 mg／kg诱导,吸入0．6％-1．2％异氟醚维持;吸入氧浓度40％;异丙酚1．5～2 mg·kg-1·h-1持续输注;维库溴铵1～2 mg间断静脉注射。每5分钟记录1次中心温度(鼻咽温),观察围术期不良反应及并发症。结果A组2例患者因手术时间超过24 h剔除,共38例进行统计。A组患者降温速率(1．11±0．05)℃／h,复温速率(0．74±0．09)℃／h。A组患者89％(16/18)在硬脑膜打开前达到目标温度34℃,平台期平均中心温度(34．3±0．5)℃,距34℃最大升幅0．52℃,最大降幅为0．23℃。A组患者67％(12／18)手术结束时中心温度恢复正常。返回ICU后A组患者中心温度(返回ICU时实测温度的均值)(35．8±0．6)℃低于B组(36．6±0．4)℃(P<0．05)。A组患者4例术后出现寒颤、3例发热、1例死亡。结论神经外科手术中应用充气温控毯可较理想地降低体温,相对于降温效率其复温效率偏低。     

低分子量聚合物电解质的合成与性能

研究了低分子量梳状聚合物电解质的合成方法及结构，性能。首先合成了不同分子量的甲基丙烯酸聚乙二醇单甲醚酯，并进一步合成了分子量一万左右的梳状聚合物电解质，结果表明：反应严格按照反应方程进行，精制产物是非晶的梳状聚合物，本聚合物体系均存在两个玻璃化转变温度，一个在100℃左右，归属为梳状聚合物主链的玻璃化转变，另一个在－20摄氏度以下，归属于侧链玻璃化转变，在室温下侧链可以运动，有利于电活性物质的迁移和扩散，并用超微电极研究了该电解质的行为。     

捻转补泻手法针刺合谷穴对其局部皮肤温度的影响

目的阐明针刺捻转补法与泻法的操作是否存在效应上的差异,并探讨其效应差异是否为补泻效应的差异.方法应用红外线热像技术,采用不同的捻转补泻手法针刺健康人合谷穴后,观察其在即刻,10、20、30min,对局部皮肤温度的影响.结果不同捻转补法与泻法的操作存在着不同程度的效应差异,其中补法可以使皮温升高,泻法可以使皮温降低,以石氏捻转补泻针法较为明显.结论1)补泻手法,补法和泻法的操作可产生不同的效应.2)不同捻转补泻手法对皮肤温度产生的升降效应为补泻效应,其中以石氏捻转补泻手法最为明显.3)证明补泻手法实施的必要性.     

Repeated measurements of mite and pet allergen levels in house dust over a time period of 8 years

BACKGROUND: Studies of the association between indoor allergen exposure and the development of allergic diseases have often measured allergen exposure at one point in time. OBJECTIVE: We investigated the variability of house dust mite (Der p 1, Der f 1) and cat (Fel d 1) allergen in Dutch homes over a period of 8 years. METHODS: Data were obtained in the Dutch PIAMA birth cohort study. Dust from the child's mattress, the parents' mattress and the living room floor was collected at four points in time, when the child was 3 months, 4, 6 and 8 years old. Dust samples were analysed for Der p 1, Der f 1 and Fel d 1 by sandwich enzyme immuno assay. RESULTS: Mite allergen concentrations for the child's mattress, the parents' mattress and the living room floor were moderately correlated between time-points. Agreement was better for cat allergen. For Der p 1 and Der f 1 on the child's mattress, the within-home variance was close to or smaller than the between-home variance in most cases. For Fel d 1, the within-home variance was almost always smaller than the between-home variance. Results were similar for allergen levels expressed per gram of dust and allergen levels expressed per square metre of the sampled surface. Variance ratios were smaller when samples were taken at shorter time intervals than at longer time intervals. CONCLUSION: Over a period of 4 years, mite and cat allergens measured in house dust are sufficiently stable to use single measurements with confidence in epidemiological studies. The within-home variance was larger when samples were taken 8 years apart so that over such long periods, repetition of sampling is recommended.     

Non-invasive temperature imaging of muscles with magnetic resonance imaging using spin-echo sequences

The application of spin-echo magnetic resonance imaging sequences on non-invasive temperature imaging for temperature mapping of human limbs is investigated. In an in vitro expriment performed on a meat sample, the equilibrium magnetisation P and the spin-lattice relaxation time T₁ are calculated from the values for the repetition time TR and the signal intensities obtained by a spin-echo sequence at different tissue temperatures tures as measured by a fibre-optic probe. T₁ is linearly correlated to the tissue temperature, and P is linearly correlated to the reciprocal value of the absolute temperature. Both effects, taken together, lead to a non-linear dependency of the signal intensity on temperature. Therefore a TR leading to maximum temperature dependency of the signal intensity is calculated and used in the futher experiments. In the in vivo experiments, the lower legs of two volunteers are cooled from outside. Images are acquired with a spin-echo sequence (1.5T, TR=1200 ms, TE=10 ms). A rise in signal intensity in the muscle with falling skin temperature is observed, particularly in more peripheral muscle layers. This study shows that spin-echo sequences can be used to monitor temperature changes and temperature differences in living muscle tissue.     

Effect of Glass Transition Temperature on the Stability of Lyophilized Formulations Containing a Chimeric Therapeutic Monoclonal Antibody

Purpose. The purpose of this study is to highlight the importance of knowing the glass transition temperature, T_g, of a lyophilized amorphous solid composed primarily of a sugar and a protein in the interpretation of accelerated stability data. Methods. Glass transition temperatures were measured using DSC and dielectric relaxation spectroscopy. Aggregation of protein in the solid state was monitored using size-exclusion chromatography. Results. Sucrose formulation (T_g ~ 59°C) when stored at 60°C was found to undergo significant aggregation, while the trehalose formulation (T_g ~ 80°C) was stable at 60°C. The instability observed with sucrose formulation at 60°C can be attributed to its T_g (~59°C) being close to the testing temperature. Increase in the protein/sugar ratio was found to increase the T_gs of the formulations containing sucrose or trehalose, but to different degrees. Conclusions. Since the formulations exist in glassy state during their shelf-life, accelerated stability data generated in the glassy state (40°C) is perhaps a better predictor of the relative stability of formulations than the data generated at a higher temperature (60°C) where one formulation is in the glassy state while the other is near or above its T_g.     

甲基强的松龙对低温保存大鼠肝脏的保护作用

应用Ｗｉｓｔａｒ大鼠肝脏离体灌流模型，用ＣＭＵ—１号液，含有甲基强的松龙的ＣＭＵ—１号液，以及缺血前预用甲基强的松龙后再用ＣＭＵ—１号液分别对肝脏进行灌洗保存。检测ＬＤＨ、ＡＬＴ、肝组织匀浆ＳＯＤ活性和ＭＤＡ含量，并观察肝组织结构。结果表明：甲基强的松龙对低温保存的离体大鼠肝脏具有保护作用     

肝动脉变异及其在肝癌介入治疗中的意义

本文收集１９９２年１月至１９９５年５月在我科作肝动脉化疗栓塞术和肝动脉化疗灌注术的中晚期肝癌１６０例，将每例病人的肝动脉造影所见与临床资料及随访结果一起进行分析。     

Regulation of local sweating in sleep-deprived exercising humans

Summary Thermoregulatory sweating [total body (m _sw,b), chest (m _sw,c) and thigh (m _sw,t) sweating], body temperatures [oesophageal (T _oes) and mean skin temperature (T _sk)] and heart rate were investigated in five sleep-deprived subjects (kept awake for 27 h) while exercising on a cycle (45 min at approximately 50% maximal oxygen consumption) in moderate heat (T _air andT _wall at 35° C. Them _sw,c andm _sw,t were measured under local thermal clamp (T _sk,1), set at 35.5° C. After sleep deprivation, neither the levels of body temperatures (T _oes,T _sk) nor the levels ofm _{sw, b},m _{sw, c} orm _{sw, t} differed from control at rest or during exercise steady state. During the transient phase of exercise (whenT _sk andT _sk,1 were unvarying), them _{sw, c} andm _{sw, t} changes were positively correlated with those ofT _oes. The slopes of them _{sw, c} versusT _oes, orm _{sw, t} versusT _oes relationships remained unchanged between control and sleep-loss experiments. Thus the slopes of the local sweating versusT _oes, relationships (m _{sw, c} andm _{sw, t} sweating data pooled which reached 1.05 (SEM 0.14) mg·cm^–2·min^–1°C^–1 and 1.14 (SEM 0.18) mg·cm^–2·min^–1·°C^–1 before and after sleep deprivation) respectively did not differ. However, in our experiment, sleep deprivation significantly increased theT _oes threshold for the onset of bothm _{sw, c} andm _{sw, t} (+0.3° C,P<0.001). From our investigations it would seem that the delayed core temperature for sweating onset in sleep-deprived humans, while exercising moderately in the heat, is likely to have been due to alterations occurring at the central level.