两种手术方式对慢性中耳炎听力改善的临床分析

目的：研究慢性中耳炎患者术后听力改善及其可能相关影响因素。方法：随访自2010年3月至2012年5月于本院耳鼻喉科进行慢性中耳炎手术的患者,将随访资料的病例行回顾性分析。结果：84例置入PORP病例术后气导听阈平均39．6±14．9dB,较术前,提高平均为13．9±13．2dB（P〈0．001）;平均气骨导差为20．5±8．5dB,气骨导差改变平均为8．8±10．7dB（P〈0．001）。术后气导听阈改善在0．5KHz,1KHz,2KHz三个频率上无明显差异（P〉0．05）,而气骨导差改善显示2KHz的改善不及0．5KHz,1KHz的气骨导差改善（（P〈0．001）。6例行颞肌筋膜鼓膜成型术病例术后气导听阈平均21．1±4.3dB,较之术前提高平均为13．6±7．2dB（P〈0．05）,平均气骨导差为11．1±4．2dB,气骨导差改变平均为6．7±4．2dB（P〈0．05）。结论：置入PORP、颞肌筋膜鼓膜成型术均可明显改善听力。慢性中耳炎手术治疗效果令人满意,羟基磷灰石假体听骨对于听力改善效果肯定。     

Inkjet Printing of Back Electrodes for Inverted Polymer Solar Cells

Evaporation is the most commonly used deposition method in the processing of back electrodes in polymer solar cells used in scientific studies. However, vacuum‐based methods such as evaporation are uneconomical in the upscaling of polymer solar cells as they are throughput limiting steps in an otherwise fast roll‐to‐roll production line. In this paper, the applicability of inkjet printing in the ambient processing of back electrodes in inverted polymer solar cells with the structure ITO/ZnO/P3HT:PCBM/PEDOT:PSS/Ag is investigated. Furthermore, the limitation of screen printing, the commonly employed method in the ambient processing of back electrode, is demonstrated and discussed. Both inkjet printing and screen printing of back electrodes are studied for their impact on the photovoltaic properties of the polymer solar cells measured under 1000 Wm^?2 AM1.5. Each ambient processing technique is compared with evaporation in the processing of back electrode. Laser beam induced current (LBIC) imaging is used to investigate the impact of the processing techniques on the current collection in the devices. We report that inkjet printing of back electrode delivers devices having photovoltaic performance comparable to devices with evaporated back electrodes. We further confirm that inkjet printing represent an efficient alternative to screen printing.     

Foreigners or multicultural citizens? Press media's construction of immigrants in South Korea

This paper examines the ways in which new immigrants to South Korea are portrayed and constructed in press media. The influx of labour and marriage migrants from Southeast Asia and China to South Korea since the early 1990s has been significant enough to cause national concerns about diversity and the country's future as a multiethnic society. Mainstream newspapers in South Korea have been a major shaper of the public opinion of diverse groups of immigrants whose presence is becoming increasingly visible in this country with a strong self-image as a mono-ethnic nation. The ways in which these new immigrants, typically lower class, are constructed in public discourses expose the nexus of citizenship, class and ethnicity. Using articles from two major South Korean newspapers between 1990 and 2008 as data, the analysis highlights the economic and historical contexts in which public discourses on new immigrants have been formed and transformed.     

Social representations of ‘mixed-race’ in early twenty-first-century Britain: content,limitations, and counter-narratives

Over the last two decades, lay and professional interest in Britain's ‘mixed-race’ population has markedly increased, following dramatic growth in mixing and mixedness. As is often the case with new phenomena, agencies in the sphere of popular culture have stepped in to offer the wider public interpretative representations of this ‘new’ group. Drawing on challenging concepts, like demographic growth rates and projections, the family ‘norm’, the ostensible benefits of heterozygosity, and the drawbacks of claimed ‘in-betweenness’, they have offered us a picture of the ‘mixed-race’ population that is sometimes at variance with lived experiences or the harder image of statistical reality. Social representation theory is used to explore the limitations of these representations and to offer a number of counter-narratives that are grounded in the evidence base.     

The role of the different fermentation media and infection processes on the infectivity of the bacterial symbionts to Spodoptera littoralis (biosduval) (Lipedoptera: Noctuidae)

Abstract

Bacterial symbionts are one of the most toxic bacteria to insect pests. They have been isolated from the intestine of the entomopathogenic nematodes. Ten strains of the entomopathogenic nematodes, that may be different, have been isolated out of different soil fauna having different crops from different Governorates in Egypt. The bacterial symbionts in these strains have been isolated and tested for production parameters using four different media. Experiments showed that both Loria Broth (LB), and Nutrient Broth (NB) gave good results in laboratory production of bacterial symbionts, concerning stability, cell size, and pigment production during culturing. Experiments using different techniques of introducing the bacterial symbionts to larvae of the cotton leafworm showed that the injection technique was the most effective among all the tested techniques. This is followed by oral and forced feeding which seemed to give equal results. On the other hand, toxicity experiments showed that the four bacterial isolates named, G-NRC-A₃, SH-NRC-A₅, SH-NRC-A₆, and N.Sinai-NRC-A₈, besides the bacterial symbiont of Steinernema abbasi, Flavimonas oryzihabitans, all give 100% mortalities to Spodoptera littoralis larvae after 24 h post-treatment at the higher dose (5×10⁴ cells/10 μl) but at the lower doses 5×10³ and 5×10² cells/10 μl of injection solution, a 100% mortality was reached after 72 h post-treatment.     

Broad‐substrate screen as a tool to identify substrates for bacterial Gcn5‐related N‐acetyltransferases with unknown substrate specificity

Due to a combination of efforts from individual laboratories and structural genomics centers, there has been a surge in the number of members of the Gcn5‐related acetyltransferasesuperfamily that have been structurally determined within the past decade. Although the number of three‐dimensional structures is increasing steadily, we know little about the individual functions of these enzymes. Part of the difficulty in assigning functions for members of this superfamily is the lack of information regarding how substrates bind to the active site of the protein. The majority of the structures do not show ligand bound in the active site, and since the substrate‐binding domain is not strictly conserved, it is difficult to predict the function based on structure alone. Additionally, the enzymes are capable of acetylating a wide variety of metabolites and many may exhibit promiscuity regarding their ability to acetylate multiple classes of substrates, possibly having multiple functions for the same enzyme. Herein, we present an approach to identify potential substrates for previously uncharacterized members of the Gcn5‐related acetyltransferase superfamily using a variety of metabolites including polyamines, amino acids, antibiotics, peptides, vitamins, catecholamines, and other metabolites. We have identified potential substrates for eight bacterial enzymes of this superfamily. This information will be used to further structurally and functionally characterize them.     

Increasing the catalytic efficiency of Candida rugosa lipase for the synthesis of tert-alkyl butyrates in low-water media

Abstract

Reactions involving tert-alcohols and their esters are generally not catalyzed by lipases. Candida rugosa lipase is one of the few lipases which shows at least limited catalytic activity towards tert-alcohols and their esters. Using transesterification of tributyrin with tertiary butyl and amyl alcohols as a model reaction, it is shown that precipitation of lipase by a tertiary alcohol in the presence of a buffer with optimum concentration enhances the catalytic activity 7 fold as compared to rates obtained with lyophilized powders. Optimization of the ratio of triglyceride to tert-alcohols and medium engineering gave an initial rate which was 41 times higher than that obtained with lyophilized powders. Hence, use of a simple enzyme formulation, coupled with optimization of reaction conditions led to Candida rugosa lipase becoming a useful catalyst for catalyzing transesterification involving tertiary alcohols.     

Enzymatic esterification of dihydrocaffeic acid with linoleyl alcohol in organic solvent media

The enzymatic esterification of dihydrocaffeic acid with linoleyl alcohol, using immobilized lipases (Lipozyme IM 20 and Novozym 435), was investigated in selected organic solvent media. Novozym 435 was found to be more efficient for catalyzing the esterification reaction. The highest enzymatic activity of 0.89 μmol esterified linoleyl alcohol/g solid enzyme/min was obtained in a hexane/2-butanone mixture of 75:25 (v/v), with an esterification yield of 75%; however, an increase in the 2-butanone proportion in the mixture up to 50% (v/v) resulted in a decrease in enzymatic activity and esterification yield to 0.38 μmol esterified linoleyl alcohol/g solid enzyme/min and 40%, respectively. The maximum esterification yield of 99.3% was obtained with a dihydrocaffeic acid to linoleyl alcohol ratio of 1:8. The electrospray ionization-mass spectroscopic structural analysis of the end products confirmed the biosynthesis of dihydrocaffeic acid ester of linoleyl alcohol, which demonstrated an anti-radical activity using 2,2-diphenyl-1-picrylhydrazyl as a radical model.     

Dynamic structure–function relationships in enzyme stabilization by ionic liquids

The stability of α-chymotrypsin and Candida antarctica lipase B (CALB) in two ionic liquids (i.e. 1-ethyl-3-methyl-imidazolium, bis[(trifluoromethyl)sulfonyl]imide [emim] [NTf₂], and butyl-trimethylamonium bis[(trifluoromethyl)sulfonyl]imide [btma] [NTf₂]) has been studied. Both enzymes were strongly stabilized by the ionic liquids, the respective half-life times increasing 96 and 1660 times, with respect to those obtained in classical organic solvents such as 1-propanol and hexane, respectively. The stabilization of both enzymes by ionic liquids may be related to the associated structural changes of proteins that they can be observed by both fluorescence and circular dichroism spectroscopic studies.