Differentiation of histochemically visualized mercury and silver

Summary Accumulations of silver and mercury can be visualized in tissue sections by a technique called autometallography or physical development. In order to make a histological differentiation between mercury and silver in tissue exposed to both metals, it is necessary to remove one of the metals while leaving the other untouched. The present paper describes a technique by which silver accumulations in histological sections can be removed by potassium cyanide, yet leaving mercury accumulations intact to be developed autometallographically.     

转基因植物中标记基因的安全性新策略

转基因植物中的除草剂和抗生素抗性标记基因潜在的生态环境和食用安全性令人担忧。解决转基因植物中抗性标记基因安全性问题有两种途径：一是转化时仍使用抗性标记基因,转基因植物再生成功后,在释放大田前将标记基因剔除;二是发展安全性标记基因用于植物遗传转化。本文综述了三种标记基因剔除系统和几种安全性标记基因在植物转化中的应用进展。     

Cancer recurrence following Mohs micrographic surgery: a mechanism of tumor persistence.

Recurrence of basal cell carcinomas after Mohs micrographic surgery is rare but known to occur. This report describes the recurrence of a basal cell carcinoma of the forehead after Mohs surgery in order to illustrate a previously undescribed mechanism of tumor persistence and recurrence despite thorough microscopic evaluation of all surgical margins. The value of the surgeon's reviewing all prior histologic sections before performing micrographic surgery, the importance of resecting all scar tissue from a previous surgical site prior to determination of tumor-free margins, and the potential usefulness of a three-tiered closure after excision of a cutaneous malignancy that involves the muscular layer are discussed.     

PCR amplification of 16S rDNA sequences in Fe-rich sediment of coal refuse drainage

Acid drainage from coal mines or coal refuse, when treated in collection ponds, results in the formation of Fe-rich sediments. The Fe in these sediments inhibits the PCR and hinders identification of bacteria using non-culture 16S rDNA molecular methods. We describe a technique that employs EDTA to dissolve and remove Fe from these sediments, yielding DNA that can be amplified by PCR. The technique allows the identification of bacterial DNA sequences and increases our understanding of the bacterial community in Fe-rich sediments.     

Development of sludge filterability test to assess the solids removal potential of a sludge bed

A qualitative sludge characterisation technique called "sludge filterability technique" has been developed. This technique enables the determination of the sludge potential for the physical removal of solids, weighing the effect of different process parameters on solids removal and identifying the mechanisms of solids removal in an upflow anaerobic sludge bed system. In this paper guidelines for conducting the test are given and a "standardised" set-up is presented. The experimental set-up and protocol are simple and the results can be obtained in a period as short as a few hours. A sludge sample is added to an upflow reactor incubated at 4 degrees C, to limit gas production, washed with an anaerobically pre-treated and suspended solids free wastewater to remove solids washed out from the sludge, and then fed with a model substrate, prepared from fish meal with a standard procedure. Several experimental runs were conducted to validate and optimise the technique. The results showed that the technique is reliable, workable and reproducible.     

Demonstration of biofilm removal from type 304 stainless steel using pulsed-waveform electropolishing

Abstract

This article describes an electrochemical method to remove bacterial biofilm from a stainless steel (SS) surface using a potential pulse/reverse pulse technique. This technique employs a periodic waveform that consists of anodic and cathodic pulses. The pulses can effectively strip a thin layer of metal off the SS surface, along with the adherent biofilm, in a saline solution. Not only can the pulses effectively remove biofilm from the SS surface, but they also regenerate the original mirror-like shiny surface. The importance of this electrochemical biofilm removal method is its wide applicability for any types of biofilms. That is, instead of directly removing the biofilm, it removes a very thin layer of the metal under the biofilm. Thus, the removal process is independent to the nature of the biofilms. Furthermore, this electrochemical biofilm removal method is rapid (less than 30?s of potential pulse time) and does not require hazardous chemicals.     

Endophytic microorganisms—promising applications in bioremediation of greenhouse gases

Bioremediation is a technique that uses microbial metabolism to remove pollutants. Various techniques and strategies of bioremediation (e.g., phytoremediation enhanced by endophytic microorganisms, rhizoremediation) can mainly be used to remove hazardous waste from the biosphere. During the last decade, this specific technique has emerged as a potential cleanup tool only for metal pollutants. This situation has changed recently as a possibility has appeared for bioremediation of other pollutants, for instance, volatile organic compounds, crude oils, and radionuclides. The mechanisms of bioremediation depend on the mobility, solubility, degradability, and bioavailability of contaminants. Biodegradation of pollutions is associated with microbial growth and metabolism, i.e., factors that have an impact on the process. Moreover, these factors have a great influence on degradation. As a result, recognition of natural microbial processes is indispensable for understanding the mechanisms of effective bioremediation. In this review, we have emphasized the occurrence of endophytic microorganisms and colonization of plants by endophytes. In addition, the role of enhanced bioremediation by endophytic bacteria and especially of phytoremediation is presented.     

The use of liposuction to contour cherubism

Yet another application of suction lipectomy equipment is presented to remove the pathologic tissue in cherubism. Owing to the variations of consistency of the material in this condition, this technique may not be successful in all patients, but it is certainly recommended when indicated.     

Specific Isolation of RNA from the Grape Powdery Mildew Pathogen Erysiphe necator, an Epiphytic, Obligate Parasite

RNA expression profiling of obligately parasitic plant microbes is hampered by the requisite interaction of host and parasite. This can be especially problematic in the case of powdery mildews, such as Erysiphe necator (syn. Uncinula necator ), which grow superficially but tightly adhere to the plant epidermis. We developed and refined a simple and efficient technique in which nail polish was used to remove conidia, appressoria, hyphae, conidiophores, and developing ascocarps of E. necator from grapevine ( Vitis vinifera ) leaves and showed that RNA isolated after removal was not contaminated with V. vinifera RNA. This approach can be applied to expression analyses throughout fungal development and could be extended to other epiphytic pathogens and saprophytes.     

A Decellularization Methodology for the Production of a Natural Acellular Intestinal Matrix

Successful tissue engineering involves the combination of scaffolds with appropriate cells in vitro or in vivo. Scaffolds may be synthetic, naturally-derived or derived from tissues/organs. The latter are obtained using a technique called decellularization. Decellularization may involve a combination of physical, chemical, and enzymatic methods. The goal of this technique is to remove all cellular traces whilst maintaining the macro- and micro-architecture of the original tissue.Intestinal tissue engineering has thus far used relatively simple scaffolds that do not replicate the complex architecture of the native organ. The focus of this paper is to describe an efficient decellularization technique for rat small intestine. The isolation of the small intestine so as to ensure the maintenance of a vascular connection is described. The combination of chemical and enzymatic solutions to remove the cells whilst preserving the villus-crypt axis in the luminal aspect of the scaffold is also set out. Finally, assessment of produced scaffolds for appropriate characteristics is discussed.     

Removal of the fermentation by-product succinyl L-tyrosine from the beta-lactamase inhibitor clavulanic acid using a molecularly imprinted polymer

Clavulanic acid is a beta-lactamase inhibitor used in therapeutic combinations with the penicillin-type antibiotics. During the fermentation leading to clavulanic acid, a succinyl L-tyrosine by-product is unavoidably formed. Occasionally, the amount of this by-product is found to be as high as 2% of the product even after standard purification operations. To further remove this impurity, we prepared a highly specific adsorbent for succinyl L-tyrosine with the molecular imprinting technique. This was performed by simultaneously using vinylbenzyl trimethylammonium chloride and methacrylic acid as the functional monomers. The imprinted polymer selectively bound succinyl L-tyrosine, and could be successfully used to remove this impurity at concentrations of less than 2% in the presence of clavulanic acid.     

Gynecomastia: suction lipectomy as a contemporary solution

Suction lipectomy is adapted for the correction of gynecomastia. Previous attempts using suction lipectomy for gynecomastia still required the use of sharp dissection for removal of the glandular breast tissue as well as excision of redundant skin. With this new technique, gynecomastia is corrected solely with the use of suction lipectomy. The technique is successful if the gynecomastia is due to excess fat or parenchymal hypertrophy. A 7-mm cannula is inserted first, to remove the adipose tissue. Then a 2.4-mm cannula is used to remove the glandular and ductal tissue. The 7-mm cannula is then reinserted to remove subareolar parenchyma and to make final contour adjustments. The surrounding subcutaneous tissue is easily undermined to avoid a saucer deformity and to allow for skin contraction. Patients return to full activities in 48 hours. A compressive garment is worn for 4 to 6 weeks. The results of 10 patients are discussed.     

Preparation of leukocyte-poor erythrocyte concentrates using a simple aspiration technic

Depletion of leukocytes from red blood cells can prevent transfusion reactions in HLA-sensitized patients. We describe a simple technique of aspiration of the buffy-coat after centrifugation of red blood cells concentrates, less than 6 days old. This method can remove 87% of the leukocytes. The average leukocyte count after aspiration is 2 x 10(8). This method is inexpensive and does not require any special equipment.     

Connecting nanoscale images of proteins with their genetic sequences

We present a technique for reconstructing biomolecular structures from scanning force microscope data. The technique works by iteratively refining model molecules by comparison of simulated and experimental images. It can remove instrument artifacts to yield accurate dimensional measurements from tip-broadened data. The result of the reconstruction is a model that can be chosen to include the physically significant parameters for the system at hand. We demonstrate this by reconstructing scanning force microscope images of the cartilage proteoglycan aggrecan. By explicitly including the protein backbone in the model, we are able to associate measured three-dimensional structures with sites in the protein primary structure. The distribution of aggrecan core protein lengths that we measure suggests that 48% of aggrecan molecules found in vivo have been partially catabolized at either the E(1480)-(1481)G or E(1667)-(1668)G aggrecanase cleavage site.     

城市污水厂除臭技术的应用综述

对目前国内外污水厂除臭技术的现状进行了综述, 介绍了目前应用于城市污水厂恶臭污染治理的多种技术, 并对其优缺点进行比较。分析结果表明, 水洗法和喷淋法简单易行, 但对臭气的去除率较低; 药剂吸收法和活性炭吸收法可以达到较好的去除效果, 但是运行费用较高; 而生物除臭法对臭气的去除率高、运行费用低、无二次污染, 是一种较为经济有效的除臭技术, 也是今后污水厂除臭技术的主要发展方向。     

环境水体微囊藻毒素微生物降解技术研究进展

湖库水体富营养化及其产生的藻毒素污染已对生态环境和人类健康构成极大威胁,而目前常规水污染控制技术存在一定的局限性,因此水环境中藻毒素处理新工艺亟待研发.鉴于环境水体中的微囊藻毒素可被微生物降解为无毒或低毒的中间产物,本文综述了微囊藻毒素的降解菌株、生物降解过程影响因素与机理、降解产物及其结构特性等,总结了目前微囊藻毒素降解菌株在水环境修复中的应用,并对今后微生物降解微囊藻毒素的研究方向进行了展望,以期为解决我国日益严峻的湖库水体藻毒素污染和饮用水安全问题提供技术思路.     

Localization of insulin degradation products to an intracellular site in isolated rat hepatocytes

In the present study, we have examined whether insulin degradation products are present on the surface of isolated rat hepatocytes and can be removed by an acid dissociation technique. Hepatocytes were incubated with [125I]insulin for 30 minutes, rapidly washed to remove unbound insulin, and then briefly exposed to acidic conditions (pH 5.0) to remove bound hormone from the cell surface. The radioactive material removed from the cell by acid dissociation and that remaining with the cells were separately analyzed by high performance liquid chromatography. The two primary degradation products of insulin present in control cell extracts were found only with the cell-associated material after acid dissociation. The insulin-sized radioactive material in the extract of acid-dissociable material consisted of only intact [125I]insulin. These results show that the two primary degradation products of insulin in rat hepatocytes are found only intracellularly and suggest that the degradation of the hormone begins after it is internalized.     

An evaluation of the effectivity of the scrub technique in quantitative ectoparasite ecology

The effectivity of the scrub technique used in quantitative parasite ecology to collect ectoparasites from mammalian skins was evaluated. This was done by reprocessing already scrubbed skins with the alkali digestion technique to remove any remaining parasites. The skins of six adult impala (Aepyceros melampus) ewes were used in the study. The results showed that the scrub technique is variable in its effectivity, and on average removed only 30.2% ectoparasites from the skins. It was also shown that the scrub technique is unreliable and more labour intensive and time consuming than the digestion technique, and should preferably not be used in quantitative studies.     

Quantifying Abrasion of Stable Substrata in Streams: A New Disturbance Index for Epilithic Biota

Abrasion is a significant disturbing force to which the streambed epilithic biota is exposed during high flow periods. However, abrasion of biota in the field has not been measured, and effects of abrasion on biota are usually inferred. We describe a method that quantifies abrasion of a standardised substrate in the field. This provides an index of the level of abrasion to which flora and fauna are exposed. The method uses autoclaved lightweight aerated concrete (ALC) blocks that are fixed in place on the streambed and subsequently abraded. Two methods were used to quantify abrasion: the change in mass of the block from before to after deployment, and the reduction in cross-sectional area of the corners of the blocks as measured by image analysis. We performed preliminary trials in the laboratory to quantify the amount of work required to remove mass from the blocks. These measurements confirmed that ALC was a consistent substrate with regards to the amount of work required to remove a given mass. The technique was field-tested during a year-long survey at six sites in the Acheron valley, south-eastern Australia. Blocks were deployed for approximately 2 months at a time at each of six sites. The method was able to distinguish average differences in abrasion between trials and sites, but neither of these factors was constant. The variability of abrasion within sites was also high. Results show that the technique in its current form can be used to provide an index of the amount of abrasion to which the epilithic biota is exposed in streams and rivers. An assessment of the strengths and weaknesses of the technique is provided, and suggestions made for further improvements and research.