基于使用负性液晶的边沿场切换模式的局部残影分析

随着液晶显示技术的发展,PPI越来越高,像素尺寸越来越小,穿透率的提升是一重要问题。负性液晶相对正性液晶具有高穿透率,较好的画面画质及较低的颜色偏差等优点,使得主流显示模式IPS、FFS使用负性液晶研究逐渐增多。但由于负性液晶自身特性,其影像残留较正性液晶更为严重,特别是模组粘合附近区域的局部面残。为了改善负性液晶局部影像残留,本文研究了实际样品影像残留严重区域与轻微区域不同测量数据,如温度、共电压(Vcom)等,发现影像残留严重区域与轻微区域的公共电压出现漂移现象,分析了影响残影的因素,并提出改善方案,实测结果证明本文改善局部残影的方法是有效的。     

由无监管供货来源引起的接触镜并发症综述

正前言:2014年1月,美国眼科医师接触镜协会的专业权威杂志《眼睛和接触镜》发表了业界著名英国学者的文献综述,指出全球未经验配师正规验配、处方、指导、随访的隐形眼镜销售会带来更大的不良反应,特别是美容平光镜片,呼吁发展中国家借鉴英美历史经验教训,消除隐患。文章发表后引起行业内外巨大反响,现重点翻译摘要内容如下。     

Localization and chemical speciation of Pb in roots of signal grass (Brachiaria decumbens) and Rhodes grass (Chloris gayana)

Lead (Pb) contamination of soils is of global importance but little is known regarding Pb uptake, localization, or the chemical forms in which Pb is found within plants, or indeed how some plants tolerate elevated Pb in the environment. Two grasses, signal grass (Brachiaria decumbens Stapf) (Pb-resistant) and Rhodes grass (Chloris gayana Kunth)(Pb-sensitive), were grown for 14 d in dilute nutrient solutions before examination of roots using transmission electron microscopy (TEM) to determine the distribution and speciation of Pb in situ. In both grasses, Pb was initially present primarily in the cytoplasm of rhizodermal and cortical cells before being sequestered within vacuoles as the highly insoluble (and presumably nontoxic) chloropyromorphite (Pb5(PO4)3Cl). In signal grass, Pb also accumulated within membranous structures (perhaps the Golgi apparatus), prior to apoplastic sequestration as chloropyromorphite. These findings suggest that the ability of signal grass to sequester insoluble Pb in the cell wall represents an additional and potentially important mechanism of Pb tolerance not possessed by the Pb-sensitive Rhodes grass.     

Analytical techniques for the estimation of sulphite binding components in ciders and wines

Summary A rapid high performance liquid chromatography (HPLC) method based on the formation of dinitrophenylhydrazine (DNPH) derivatives was developed for the analysis of the major sulphite binding carbonyls in fermented ciders (acetaldehyde, pyruvate, α-ketoglutarate, galacturonic acid and L-xylosone). The synthesis of the DNPH derivative of L-xylosone, for use as an analytical standard, is also described. These data were used to calculate the predicted sulphite binding power of fermented ciders at various levels of free sulphur dioxide. Analysis of free and bound sulphur dioxide in the ciders, after equilibration with known amounts of added sulphite, was used to calculate the experimental sulphite binding power. These techniques were applied to a major study of sulphite binding in ciders which is reported in an accompanying paper.     

Influence of Zinc on Distiller's Yeast: Cellular Accumulation of Zinc and Impact on Spirit Congeners

Accumulation of zinc by a whisky distilling yeast strain of Saccharomyces cerevisiae was studied during fermentation of malt wort and synthetic defined medium. Zinc uptake by yeast cells was very rapid in malt wort, as zinc (0.32 μg/mL) was completely removed from the fermentation medium within one hour. The type of fermentable carbohydrate had an impact on the kinetics of zinc accumulation, with maltose most effective at enhancing metal uptake at zinc concentrations above 3.2 μg/mL. Enriching yeast cells with zinc by “preconditioning” impacted on the production of flavour congeners in the distillates produced from fermented cultures. Such distillates were characterised by an altered flavour and aroma profile. In particular, the production of some higher alcohols increased when yeast cells were preconditioned with zinc. This phenomenon is yeast strain related. Industrial fermentation processes, including brewing and distilling, may benefit from optimization of zinc bioavailability in yeast cultures resulting in more efficient fermentations and improved product quality.     

Zinc deprivation inhibits extracellular matrix calcification through decreased synthesis of matrix proteins in osteoblasts

Scope: Zinc is implicated as an activator for bone formation, however, its influence on bone calcification has not been reported. This study examined how zinc regulates the bone matrix calcification in osteoblasts. Methods and Results: Two osteoblastic MC3T3‐E1 cell subclones (SC 4 and SC 24 as high and low osteogenic differentiation, respectively) were cultured in normal osteogenic (OSM), Zinc deficient (Zn–, 1 μM), or adequate (Zn+, 15 μM) media up to 20 days. Cells (SC 4) were also supplemented with (50 μg/mL) or no ascorbic acid (AA) in combination with Zinc treatment. Zn– decreased collagen synthesis and matrix accumulation. Although AA is essential for collagen formation, its supplementation could not compensate for Zinc deficiency‐induced detrimental effects on extracellular matrix mineralization. Zn– also decreased the medium and cell layer alkaline phosphatase ALP activity. This decreased ALP activity might cause the decrease of Pi accumulation in response to Zn–, as measured by von Kossa staining. Ca deposition in cell layers, measured by Alizarin red S staining, was also decreased by Zn^–. Conclusion: Our findings suggest that zinc deprivation inhibits extracellular matrix calcification in osteoblasts by decreasing the synthesis and activity of matrix proteins, type I collagen and ALP, and decreasing Ca and Pi accumulation. Therefore zinc deficiency can be considered as risk factor for poor extracellular matrix calcification.     

Struggle with hydrogel CL wear increases with age in young adults

Purpose

To report the symptoms and experiences associated with habitual hydrogel (Hyd) and silicone hydrogel (SiHy) contact lenses (CLs) among young adults and measure their association with age.

Methods

Questionnaire responses from 699 Hyd and 183 SiHy wearers were analyzed to test the association of age with features indicating struggle with CL wear. Prevalence by age was compared between groups with Pearson's chi-square and within groups with Spearman's correlation coefficient.

Results

Hyd and SiHy groups were similar for sex and age distribution. Diagnosis of dry eye increased with age in the Hyd wearers from 10.6% to 21.1% (18-24 vs. 30-35 years), but was approximately 19% in the SiHy wearers across age. Adverse environments caused more discomfort with Hyd than SiHy lenses and Hyd wearers’ discomfort increased with age (smoky (p = 0.0001), dry air environments (p = 0.002), after napping or sleeping (p = 0.004). More Hyd wearers considered discontinuation of CL wear with age, from 4.6% to 14.2% (18-24 vs. 30-35 years, p < 0.04), but the proportion remained steady at 9% across age for SiHy wearers (p = 0.46).

Conclusions

From 18 to 35 years, hydrogel CL wearers reported increasing struggle with CL wear and more negative ratings compared to SiHy wearers. Older hydrogel CL wearers were also more likely to consider discontinuing CL wear compared with younger hydrogel or silicone hydrogel CL wearers in general. Young adult CL wearers should be routinely queried directly about specific aspects of CL wear in order to determine whether different lens types should be prescribed to avoid abandonment of CL wear.     

An improved HPLC method for single‐run analysis of the spectrum of hop bittering compounds usually encountered in beers

A single‐run reverse phase‐high performance liquid chromatography method for the quantification of humulinones, α‐acids, iso‐α‐acids and reduced iso‐α‐acids (where present) in commercial beer samples is presented. The method utilizes a binary solvent system consisting of (A) 1% v/v acetic acid and (B) 0.1% v/v orthophosphoric acid in acetonitrile. Separation was achieved on a Purospher® star RP‐18 column (250 × 46 mm, 3 µm) with a flow rate of 0.5 mL/min. The compounds of interest eluted within 32 min. The method was fully validated according to International Conference on Harmonization guidelines and subsequently applied to monitor degradation of hop acids in a storage trial where four lager beers were aged at 28 and 38 °C for 70 and 60 days, respectively. Results confirmed the widely reported degradation through storage of trans‐iso‐α‐acids whilst demonstrating that the HLPC method was sufficiently sensitive to monitor and model this degradation. One beer exhibited a significantly lower (P < 0.05) rate of trans‐iso‐α‐acid degradation than the other conventionally hopped beers in the study, which might have been linked to its higher pH (4.71 vs 4.36). The relative stability of reduced iso‐α‐acids during ageing was also confirmed.