萘普生合成工艺的研究

以６－甲氧基－２－萘乙酮为原料,在氢氧化钾的作用下,与硝基甲烷亲核加成,脱氢烯比后,用Ｆｅ粉还原,再用浓硝酸氧化脱水即得萘普生。     

Rye Chromosome Variability in Wheat–rye Addition and Substitution Lines

In a study of polymorphism and stability in rye chromosomes, three rye varieties and the sets of wheat-rye addition and substitution lines were compared using two non-homologous highly repetitive DNA families, pSc200 and pSc250. The rye varieties, Petkus, Imperial and Onohoiskaya, showed polymorphism for the presence and the size of the pSc200 in-situ hybridization signals on chromosome pairs, 2R, 4R and 7R, and the pSc250 signals on chromosomes, 5R, 6R and 7R. Chromosome 1R was heteromorphic within the Onohoiskaya variety. Differences in the distribution of chromosome polymorphisms imply that intervarietal changes to these highly repetitive DNA families occurred independently, despite their juxtaposition or even overlapping locations in subtelomeric heterochromatic regions. In the set of Saratovskaya 29 wheat/Onohoiskaya substitution lines, only chromosome 2R was altered relative to its counterpart in the parental rye variety due to amplification of the pSc250 signal on the long arm, although this did not exceed intervarietal polymorphism. In the set of Chinese Spring wheat/Imperial addition lines, only two Imperial chromosomes, 4R and 6R, were unchanged. We detected the loss of one or both rye homologous chromosomes, the loss of one arm, and the deletion of subtelomeric heterochromatin accompanied by the loss of the pSc200 signal. The results show that Saratovskaya 29/Onohoiskaya chromosome substitution lines possess increased chromosome stability compared with Chinese Spring/Imperial addition lines. This revised version was published online in August 2006 with corrections to the Cover Date.     

Digital images

This tutorial introduces basic digital image processing concepts. An increasing fraction of fluoroscopic images are handled and processed using digital tools. The quality of an image in digital format depends on both the technical details of the digitization process and on the quality of the starting scene. Digital tools yield images that are difficult or impossible to achieve using analog techniques. Proper processing improves the observer's perception of clinical information. Cathet. Cardiovasc. Intervent. 46:487–496, 1999. © 1999 Wiley-Liss, Inc.     

Preliminary Study of the Rhenium Addition on the Structure and Mechanical Properties of Tungsten Heavy Alloy

The results of structure and mechanical property investigations of tungsten heavy alloy (THA) with small additions of rhenium powder are presented. The material for the study was prepared using liquid phase sintering (LPS) of mixed and compacted powders in a hydrogen atmosphere. From the specimens, the samples for mechanical testing and structure investigations were prepared. It follows from the results of the microstructure observations and mechanical studies, that the addition of rhenium led to tungsten grain size decreasing and influencing the mechanical properties of W-Ni-Fe-Co base heavy alloy.     

Synthesis of hydroxytelechelic ε‐caprolactone/poly(ethylene terephthalate) co‐oligomers, 1

In the presence of ethylene glycol, poly(ethylene terephthalate) (PET) undergoes chain scissions with the formation of α,ω‐hydroxyl oligomers, through classical transesterification by alcoholysis. ε‐Caprolactone was subsequently added on the hydroxyl end groups of PET oligomers by ring‐opening polymerization at different molar ratios of ε‐caprolactone to PET oligomers. The chemical structure of the products was investigated by size exclusion chromatography, ¹H NMR spectroscopy, and differential scanning calorimetry. A large majority of these products are soluble in common organic solvents. The thermal and ¹H NMR analyses reveal that the transesterification between base units of PET oligomers and ε‐caprolactone during the synthesis is always present whatever the reaction conditions. This phenomenon leads to copolymers having thermal properties different from those of PET. However, some co‐oligomers present the interest of keeping properties close to those of PET. The main purpose of this study was the synthesis of PET co‐oligomers that are soluble in some organic solvents that would make their use easier, and so that they can be used further as hard segment precursers for polycondensation reactions.

Ring‐opening polymerization of ε‐caprolactone onto hydroxytelechelic oligomers of PET.     

穴位按摩配合川芎茶调散加减治疗血管性头痛30例疗效观察

目的：观察穴位按摩配合川芎茶调散加减治疗血管性头痛的临床疗效.方法：30例血管性头痛的患者采用穴位按摩配合川芎茶调散加减治疗.结果：显效12例（40.0%）,有效14例（46.67%）,无效4例（13.33%）,总有效率为93.33%.结论：穴位按摩配合川芎茶调散加减治疗血管性头痛疗效显著.     

Theoretical performance of progressive addition lenses with poorly measured individual parameters

Purpose

The aim of this paper was to present a theoretical study of how poorly measured individual parameters affect the optical performance of progressive addition lenses (PALs). Modern progressive lenses can be prescribed based on parameters such as vertex distance, pantoscopic and wrap angles. These parameters can be measured from the lens wearer using specific devices; however, not all of them can be measured with the same precision, and the impact of measurement errors on the lens performance is still unknown.

Methods

Data from 1900 patients were used to simulate the performance of four PAL designs with different degrees of complexity: perfect individual design, individual design with induced errors in the individual parameters, optimised design and conventional/basic design. For each patient and design, a quality metric was calculated to describe the optical performance of the lens.

Results

The design having the best performance was the perfect individual design, followed by the individual design with induced errors, the optimised design and finally the conventional/basic design.

Conclusions

Individual designs with measurement errors have better optical performance than lenses with less complexity, such as the optimised or conventional designs. This knowledge is useful for the eye care professional to make informed choices when dispensing these lenses.     

Trapezius activity during personal computer work with progressive addition lenses for general purpose and for computer work in neophytes

Introduction

This study analysed the impact of general purpose progressive addition lenses (GP-PALs) and computer progressive addition lenses (PC-PALs) on the activity of the trapezius muscle during computer operation.

Methods

In this randomised, single-blinded, crossover study, surface electromyography (SEMG) signals were recorded bilaterally from the trapezius muscle during a 30-min computer task performed wearing different presbyopic corrections. The amplitude probability distribution function and its percentiles, gap frequency, muscular rest time and sustained low-level muscle activity periods were analysed in 32 subjects with artificially induced presbyopia. Subjectively perceived differences in vision and postural load between lenses were evaluated using a seven-item questionnaire (non-standardised, visual analogue scale ranged from 1 [bad] to 100 [good]).

Results

Considering the SEMG data, no significant difference in the muscular activity of the trapezius muscle was observed when using GP-PALs or PC-PALs for computer operation. However, PC-PALs showed statistically and clinically significantly higher results for subjectively perceived visual quality (78.4–31.3; p < 0.001), spontaneous tolerance (79.2–31.3; p < 0.001) and field of view (75.9–23.5; p < 0.001) compared with GP-PALs.

Conclusions

Even though the electromyographic approach did not show a significant differentiation between the lenses, the subjective evaluation was clearly in favour of PC-PALs. Eye care practitioners should always take an occupational history of presbyopes, ask about the workplace situation and consider the use of PC-PALs.     

角膜基质透镜植入联合角膜胶原交联术治疗圆锥角膜术后角膜上皮重塑

目的：观察飞秒激光辅助下的角膜基质透镜植入联合角膜胶原交联术(SLAK-CXL)治疗进展期圆锥角膜术后角膜上皮重塑情况，探讨角膜上皮重塑规律和影响因素，为进一步屈光矫正提供良好的时机选择。

方法：回顾性、观察性研究。纳入2020-09/2021-10于我院接受SLAK-CXL的圆锥角膜患者28例29眼，记录手术前后视力、眼压(IOP)、屈光度、角膜曲率及角膜上皮厚度(CET)，观察CET变化趋势，并根据透镜厚度和植入深度分析影响CET变化的因素。

结果：与术前比较，纳入患者术后1mo角膜前表面曲率平坦值(K_f)和陡峭值(K_s)均升高(P<0.05)，术后1、2、6mo，1a角膜最薄点厚度(TCT)均升高(P<0.05)。纳入患者术后CET随时间变化而变化，中央区CET变化趋势较明显。与术前相比，术后1、2、6mo，1a旁中央区上方、鼻上方、鼻侧和颞上方CET均降低，中周区上方、颞侧、颞上方CET均降低，外周区鼻上方CET均增加。术后1a，不同植入透镜深度和厚度患者各分区角膜上皮厚度变化量均无差异(P>0.05)。

结论：首次发现SLAK-CXL治疗圆锥角膜术后角膜形态发生变化，CET呈先减少再增加再减少趋势，术后1a中央区、旁中央区CET降低，中周区、外周区CET增加，且角膜上皮重塑程度与术中植入透镜深度和厚度均无关。     

Recognizing the causes of in-hospital cardiac arrest — A survival benefit

BackgroundThe in-hospital emergency team (ET) may or may not recognize the causes of in-hospital cardiac arrest (IHCA) during the provision of cardiopulmonary resuscitation (CPR). In a previous 4.5-year prospective study, this rate of recognition was found to be 66%. The aim of this study was to investigate whether survival improved if the cause of arrest was recognized by the ET.MethodsThe difference in survival if the causes were recognized versus not recognized was estimated after propensity score matching patients from these two groups.ResultsOverall survival to hospital discharge was 25%. After propensity score matching, the benefit of recognizing the cause regarding 1-hour survival of the episode was 29% (p < 0.01), and 19% regarding hospital discharge, respectively. Variables commonly known to affect the outcome after cardiac arrest were found to be balanced between the two groups. The largest difference was found in patients with non-cardiac causes and non-shockable presenting rhythms. Patient records and pre-arrest clinical symptoms were the information sources most frequently utilized by the ET to establish the causes of arrest.ConclusionsPatients suffering an IHCA showed a substantial survival benefit if the causes of arrest were recognized by the ET. Patient records and pre-arrest clinical symptoms were the sources of information most frequently utilized in these instances.