Packing and Uniaxial Alignment of Liquid Crystalline Oligofluorenes

Summary: Liquid crystalline oligomers of 9,9‐bis(2‐ethylhexyl)fluorene of defined degree of polymerization 4, 5, 6, and 7 were investigated by X‐ray diffraction in the non‐oriented and in the aligned state. The diffraction data give evidence for a smectic B type phase for all of the oligomers. Quenching below the glass transition does not change the structure of the liquid crystalline phase. This allows to align spin‐coated films of these oligomers on rubbed polyimide substrates to give monodomain films. These are stable against thermal disordering below T_g, e.g. at room temperature. The degree of alignment is characterized by the dichroic spectra and polarized fluorescence spectra. Dichroic ratios and polarization ratios increase substantially with the chain length and values as high as D = 23 and P = 41 are obtained for the heptamer. The type of packing of the oligomers in the LC phase is discussed based on the X‐ray single crystal structure of models. In one such model the packing of the 2‐ethylhexyl side chains could be fully resolved, while the other model reveals the torsional angle between adjacent fluorene units in the same molecule as 144.2° which corroborates earlier work based on fiber diffraction of corresponding polyfluorenes.

     

Accessibility, clinical effectiveness, and practice costs of providing a telephone option for routine asthma reviews: phase IV controlled implementation study.

BACKGROUND: Attendance for routine asthma reviews is poor. A recent randomised controlled trial found that telephone consultations can cost-effectively and safely enhance asthma review rates; however, concerns have been expressed about the generalisability and implementation of the trial's findings. AIM: To evaluate the effectiveness of a telephone option as part of a routine structured asthma review service. DESIGN OF STUDY: Phase IV controlled before-and-after implementation study. SETTING: A large UK general practice. METHOD: Using existing administrative groups, all patients with active asthma (n = 1809) received one of three asthma review services: structured recall with a telephone-option for reviews versus structured recall with face-to-face-only reviews, or usual-care (to assess secular trends). Main outcome measures were: proportion of patients with active asthma reviewed within the previous 15 months (Quality and Outcomes Framework target), mode of review, enablement, morbidity, and costs to the practice. RESULTS: A routine asthma review was provided for 397/598 (66.4%) patients in the telephone-option group compared with 352/654 (53.8%) in the face-to-face-only review group: risk difference 12.6% (95% confidence interval [CI] = 7.2 to 17.9, P<0.001). The usual-care group achieved a review rate of 282/557 (50.6%). Morbidity was equivalent in the three groups; however, enablement (P = 0.03) and confidence (P = 0.007) in asthma management were greater in the telephone-option versus face-to-face-only group. The cost per review achieved by providing the telephone-option service was lower than the face-to-face-only service (10.03 pounds versus 12.74 pounds, mean difference 2.71 pounds; 95% CI = 1.92 to 3.50, P<0.001); usual-care costs were 11.85 pounds per review achieved. CONCLUSION: Routinely offering telephone reviews cost-effectively increased asthma review rates, enhancing patient enablement and confidence with management, with no detriment to asthma morbidity. Practices should consider a telephone option for their asthma review service.     

窦性起搏对心室肌纤维自发节律位相重置性质的数值研究

本文应用Beeler-Reuter模型，选取损伤电流I＝23μA，产生自发振荡，施加不同程度的电流脉冲刺激，研究窦性起搏对心室肌纤维自节律位相重置的过程，结果表明：当外加电流脉冲强度小于14时，体现位相奇重置，反之，体现位相偶重置，并给出位相重置函数。     

Factors modulating the sensitivity of the relaxation to the loading conditions in rat cardiac muscle

The load sensitivity of the relaxation phase was studied in rat papillary muscle, with isotonic afterloaded contractions and stretches applied after the peak of isometric twitches.The tension decay occurred earlier in isotonic than in isometric contractions. When a central region of the preparation was marked with small stainless steel pins, a lengthening of this region could be shown during relaxation of isometric (fixed end) contractions. This lengthening was earlier and faster in isotonic afterloaded contractions. Therefore the sensitivity of relaxation to load or length changes could be described in the context of the general mechanism of relaxation which takes into account the non uniform behaviour of the muscle and the internal movement during contractions.Interventions which decelerate the activation decay rate had different effects on the load dependence of relaxation. Caffeine addition and substitution of strontium for calcium abolished the load sensitivity while a temperature reduction had no influence on it.     

多发性骨髓瘤患者血清IL-6活性与急性相蛋白浓度的相关性研究

运用敏感的B_9细胞增殖试验检测了81例多发性骨髓瘤(MM)患者血清IL-6活性,同时分析了标本的几种急性相蛋白含量,结果表明,68％MM患者血清中IL-6活性大于5μ/ml(正常对照为5μ/ml以下),几种急性相蛋白中C-反应性蛋白(CRP)在MM时升高(P<0.01),平均达正常对照组的17倍以上,MM患者补体C_4与正常对照组无差异(p>0.05),C_3、白蛋白及转铁蛋白在MM时分别比正常下降24.42％、38.83％和32.80％,且与疾病分期有关,在血清IL-6大于5μ/ml的55例中,IL-6活性与CRP、C_3、白蛋白的相关系数分别为0.46,-0.34和-0.29,IL-6与转铁蛋白浓度相关不明显。本文结果提示:CRP、C_3及白蛋白等含量的变化可作为反映MM病情的简易而敏感的指标。     

Control of the rat's circadian self-stimulation rhythm by light-dark cycles.

Rats with hypothalamic and septal electrodes were maintained in continuous test environments where bar-press responses produced brief reinforcing electrical stimulations. Long-term trends in response emission were measured under continuous exposure to light, dark and 12 hr light-dark alternations. In addition, transient behavioral adjustment to sudden 180 degrees phase shifts in the light-dark schedule was studied. The ambient light condition was found to control the period and phase of the circadian rhythm of brain self-stimulation behavior, as quantified by Fourier analysis. The circadian period was greatest under constant light (up to 24.90 hr under dim illumination), and approximated 24.00 hr under constant dark. Successful nocturnal entrainment to 12 hr light-dark alternations was obtained, with the peak of the 24 hr Fourier fundamental occurring in the middle-to-late dark segments. Three to 11 days were required for re-entrainment to 180 degrees light-dark phase shifts, during which the behavioral oscillation period increased to values comparable to periods under constant light. The rate of re-entrainment appeared to be proportional to illumination intensity during light segments.     

Conjugation of DNA fragments to protein carriers by glutaraldehyde: immunogenicity of oligonucleotide-hemocyanin conjugates

The practical realization of the concept of specific immunotherapy for systemic lupus erythematosus (SLE) has been hampered, thus far, by an inability to link DNA fragments to carrier protein. In this paper, a novel technique is described, in which glutaraldehyde is the linking agent. A 2-stage method was used to link oligonucleotides to a soluble protein carrier, such as keyhole limpet hemocyanin (KLH) or human gamma globulin (HGG), whereas a 1-stage technique was sufficient to link oligonucleotides to sheep red cells. Both the ultraviolet absorbance spectrum and diphenylamine assay demonstrated that oligonucleotides were coupled to soluble protein. The conjugate of oligonucleotide to protein carrier appears to be recognized by anti-DNA antibody since oligonucleotide linked to either KLH or HGG inhibited the binding of anti-DNA antibody in vitro, and oligonucleotide-coupled sheep cells are agglutinating by seropositve sera from lupus patients. In addition, oligonucleotide-KLH raised hemagglutinating antibody to denatured DNA in C57BL/6, DBA/2 or NZB mice, as well as IgG antibody as detected by SPRIA in C57BL/6 and DBA/2 mice. The significance of this new method for the development of an antigen specific therapy of SLE is discussed.     

Perceptual Performance as a Function of Intra-Cycle Cardiac Activity

The purpose of the experiment was to test the hypothesis of a systematic change in perceptual performance within a single cardiac cycle due to the activity of the baroreceptors in carotid sinus. As an index of perceptual performance the d_s-parameter from signal detection theory (TSD) was used. A 1000 Hz sine tone had to be detected in a background of white noise. Each of 4 subjects received on the average 4605 noise or noise plus tone stimuli distributed over 10 experimental sessions. When comparing performance during time intervals before and after baroreceptor activity onset no significant difference was found. Also, when tracing perceptual performance over the whole cardiac cycle in steps of 66,100, and 200 msec, no systematic variation could be detected. For steps of 33 msec a rhythmic pulsation of perceptual performance of about 8 Hz appeared. An influence of electrical activity of the brain on perceptual performance was postulated. This activity would have to be time-locked to carotid sinus baroreceptor activity.     

热力学模型对石油低压汽液平衡计算的适用性

以Maxwell-Bonnel图拟合式、对比态Antoine方程及Pitzer-Riedel关联式分别求算饱和蒸汽压P^0,并用RoultK值（K＝P^0／P）,计算窄留分K值。根据实测的中原、孤岛和克拉玛依石油馏分低压K值,考察上述三式,结果表明：对比态Antoine式预测精度是最好的,其温度预测绝对平均偏差为7．0℃,K值预测平均相对偏差为15．6％,其他两模型偏差均较大。