New stand magnifiers do not meet rated levels of performance

A new range of stand magnifiers has been released by the COIL company in the United Kingdom. Examination of these magnifiers reveals that they fail to deliver the rated magnifications labelled prominently on the appliances, as a result of the manufacturer's conformance with the requirements of the German DIN standard and the use of back vertex power (F'_v) rather than equivalent dioptric power (F_m) of the magnifier. In this study we provide information on the optometric parameters of these new stand magnifiers that will assist the more accurate specification of improvements in vision expected from their use.     

The HGAR1 familial hypercholesterolemia pedigree

Data on 232 members of a single pedigree, descended from two pairs of original parents, were made available to the participants of Genetic Analysis Workshop 8 (GAW8). In addition to information concerning age and sex, measurements for 10 quantitative traits and genotypes at 22 polymorphic marker loci were also provided for a subset of 193 of these family members. © 1993 Wiley-Liss, Inc.     

Monolateral hypoplasia of the motor vagal nuclei in a case of sudden infant death syndrome

During the development of motor vagal nuclei (MVN), the neuroblasts of the myeloencephalic basal plate migrate in the dorsolateral direction to form the dorsal motor vagal nucleus (DMVN) and ventrolaterally to form the ventral motor vagal nucleus (VMVN). Those neuroblasts that remain close to the median sulcus will form the hypoglossal nucleus. In support of the congenital origin of the alteration of the MVN in sudden infant death syndrome (SIDS), we report the case of an 8‐month‐old female child who was found dead in her cot. The neuropathological assessment revealed that the medullary triangle of the 4th ventricle floor was asymmetric, owing to the presence of three prominences to the left side of the median sulcus. The medial prominence corresponded to the hypoglossal nucleus, which showed a marked increase in the number of large neurons; the intermediate prominence corresponded to the DMVN whose large neurons were reduced and were recognizable mainly at the level of the medial fringe; the lateral prominence corresponded to the solitary nucleus. The left solitary tract showed a reduction of the transverse diameter. Also, the left VMVN showed marked reduction in the number of neurons. Inflammatory and astrocytic reactions were absent. We suggest that in SIDS cases the hypocellularity of the MVN and the increased number of neurons of the hypoglossal nucleus are intimately related, indicating a congenital alteration due to incomplete migration of the vagal neuroblasts with abnormality of the autonomic cardio‐respiratory control.     

婴儿母乳喂养与学龄前肥胖症关系的病例对照研究

①目的　探讨婴儿期母乳喂养行为与学龄前期单纯性肥胖症发生之间的关系。②方法　对 180 0名4～ 5岁儿童的婴儿期母乳喂养情况及其体质指数 (BMI)、发育情况等进行调查 ,分析母乳喂养类型和持续时间与学龄前肥胖症发生之间的关系。③结果　单因素分析发现 ,4个月内只喂母乳、主要喂母乳、母乳与配方奶量基本相同、主要喂配方奶、只喂配方奶者 4～ 5岁时肥胖发生率分别为 12 .6 3% ,13.0 4 % ,16 .98% ,18.18% ,30 .0 0 % ;儿童母乳喂养持续时间 0 ,<1,1～ 3,4～ 6 ,7～ 9,>9个月者 4～ 5岁时肥胖发生率分别为 2 9.4 1% ,30 .0 0 % ,33.33% ,17.2 4 % ,13.92 % ,12 .2 2 % .母乳喂养类型和持续时间不同的儿童学龄前期单纯性肥胖症发生率不同 ,差异有显著性 (χ2 =10 .4 0 7,P <0 .0 5 ;χ2 =2 0 .90 3,P <0 .0 0 1)。多因素Logistic回归分析发现 ,4个月内喂配方奶量越多 ,肥胖发生率越高 (OR =1.12 0 ) ;母乳喂养持续时间越长 ,肥胖发生率越低 (OR =0 .782 )。④结论　婴儿母乳喂养对学龄前期肥胖症的发生有预防作用 ;婴儿期应提倡母乳喂养 ,并尽可能延长母乳喂养时间至 9个月以上。     

脐血铅含量与婴儿神经行为发育的探讨

目的：了解广西地区儿童铅中毒状况，研究铅对婴儿神经发育的影响。方法：选择1020名婴儿，以脐血铅作为铅暴露示标，3月龄时在贝利（Bayley)婴儿发育表上以精神发育指数（MDI）和心理运动发育指数（PDI）为效应示标。结果：血铅≥0．48μmol/L的婴儿其MDI和PDI明显落后于相对低铅组，随着分界线的下移，两组间MDI和PDI差别渐趋缩小，当分界线为0.24μmol/L时，高、低铅组MDI和PDI已不存在统计学差异。结论：当血铅≥0.48μmol/L时，婴儿神经行为发育即可受到不利影响。     

妊娠合并肝内胆汁郁积症的围生儿结局57例分析

目的 探讨妊娠合并肝内胆汁郁积症（ICP）患者致围生儿不良结局的相关指标。方法 总结本院57例ICP患者的相关临床资料，将其与围生儿结局进行分组对照分析。结果 血清胆汁酸升高与围生儿不良结局关系不明显（P＞0.05)；血清转氨酶水平在产生围生儿不良结局组与未产生围生儿不良结局组之间有显著性差异（P＞0.01)；皮肤瘙痒持续时间大于3周组围生儿不良结局发生率与持续时间小于3周组有显著性差异（P＜0.05)；有、无NST基线变异消失组的围生儿不良结局发生率有极显著性差异（P＜0.01)。结论 血清转氨酶水平、皮肤瘙痒持续时间及NST基线变异是否消失是预示围生儿不良结局的相关指标。     

The Treatment of Low Grade Cerebral Astrocytomas by Radiotherapy in Queensland

The records of 108 adult patients with supratentorial low grade astrocytoma presenting between 1/1/80 and 31/12/87 were examined for the following factors which might affect survival: patient age, extent of surgical resection, site of tumour, tumour grade, radiation field size and radiation dose. Univariate analysis showed that patient age, field size and radiation dose were significant prognostic factors, but with multivariate analysis only patient age and radiation field size were significant independent variables. It is possible that field size is a proxy variable for tumour size.     

State and output feedback design for robust tracking of linear systems with rate limited actuators

A design technique (Control of Uncertain Systems with Bounded Inputs, Tarbouriech S, Garcia G, (Eds), Lecture Notes in Control and Information Sciences, vol. 227 , Springer: Berlin, 1997; 173–186) recently proposed for stabilization of a linear system with rate‐limited actuators is utilized to design feedback laws that cause the system output to track a desired command signal. This design technique combines two design techniques recently developed for linear systems with position limited actuators, piecewise‐linear LQ control (Automatica, 1994; 30 : 403–416) and low‐and‐high gain feedback (IEEE Trans. Automat. Control, 1996; 41 : 368–378), and hence takes advantage of both design techniques, while avoiding their disadvantages. In the case that only the output is available for feedback, the performance of the state feedback law is preserved by the use of a fast observer. An open‐loop exponentially unstable fighter aircraft is used to demonstrate the effectiveness of the proposed control design method. Copyright © 2002 John Wiley & Sons, Ltd.     

河南食管癌高、低发区无症状人群食管固有膜血管乳头的变化

目的：探讨食管癌高、低发区无症状居民食管上皮固有膜血管乳头（简称乳头）增生特征（乳头密度和高度）及其与病变分布的关系，加深对食管癌变早期形态学变化特征的了解。方法：2480例无症状人群食管粘膜活检组织，采用食管癌高低发区食管纤维内镜检查，粘膜活检，组织病理学检查和形态学测量技术对食管乳头的分布特征及其与病变的关系进行分析。结果：食管癌高低发区居民食管中、下段乳头升高（≥上皮厚度的1／2）发生率之间差异并不明显（P＞0．05），但是，高发区居民食管中段乳头密度（乳头数目／mm)明显高于下段，并高于低发区居民食管中段的乳头密度（P＜0．05）；高发区居民食管上皮乳头升高伴基底细胞过度增生患者明显高于正常人（P＜0．05），而低发区未观察到类似情况。结论：乳头增生表现为乳头数目增多和乳头升高是食管癌高发区人群食管上皮特征性形态学变化，高分区居民上皮乳头升高伴明显基底细胞过度增生，提示乳头增生可能是食管癌变极早期阶段的重要形态学变化，反映了上皮细胞的增生状态。