Air pollution control through biotrickling filters: a review considering operational aspects and expected performance

The biological removal of pollutants, especially through biotrickling filters (BTFs), has recently become attractive for the low investment and operational costs and the low secondary pollution. This paper is intended to investigate the state of the art on BTF applications. After an overview on the biodegradation process and the typical parameters involved, this paper presents the analysis of a group of 16 literature studies chosen as the references for this sector. The reference studies differ from one another by the pollutants treated (volatile organic compounds [VOC], hydrogen sulphide, nitrogen oxides and trimethylamine), the geometry and size of the BTFs, and the procedures of the tests. The reference studies are analyzed and discussed in terms of the operational conditions and the results obtained, especially with respect to the removal efficiencies (REs) and the elimination capacities (ECs) of the pollutants considered. Empty bed residence time (EBRT), pollutant loading rate, temperature, pH, oxygen availability, trickling liquid flow rate, inoculum selection and biomass control strategies revealed to be the most important operational factors influencing the removal performance of a BTF.     

Priapism: a review

Priapism is persistent penile erection in the absence of sexual stimulation. The pattern of blood flow to the penis that occurs during normal erection is altered so that sustained priapism may result in edema, increased risk of abrasion, tissue drying and necrosis of the penis. Numerous causes have been reported in animals and humans. The prognosis depends on the type of priapism and the amount of time that passes before therapeutic intervention. Surgical methods, such as aspiration and shunting procedures, have traditionally been used to treat priapism but carry a risk of postsurgical complications. Use of alpha-agonists for treatment of priapism in humans is often successful and avoids the risks of impotence and other surgical complications. Investigation of the use of alpha-agonists for treatment of priapism in animals should be considered.     

Recovery from training: a brief review: brief review

Athletes spend a much greater proportion of their time recovering than they do in training. Yet, much attention has been given to training with very little investigation of recovery. The purpose of this review is to stimulate further research into this vital area of training. Recovery can be categorized in three terms: i) immediate recovery between exertions; ii) short-term recovery between repeats (e.g., between resistance sets or interval bouts); and iii) training recovery between workouts. The focus of this review is training recovery. Full training recovery is essential to optimal performance and improvement. This review includes an examination of extant research on recovery and a very brief review of some potential modalities and techniques for hastening recovery and the time course of recovery and responses to some treatments. Measures of recovery and practical considerations are discussed briefly. Much research is needed in this area, but there are obstacles to high quality research. Attention must be given to key issues in research on recovery, especially the individual response to recovery treatments.     

Artificial molecular sieves and filters: a new paradigm for biomolecule separation

Patterned regular sieves and filters with comparable molecular dimensions hold great promise as an alternative to conventional polymeric gels and fibrous membranes to improve biomolecule separation. Recent developments of microfabricated nanofluidic sieves and filters have demonstrated superior performance for both analytical and preparative separation of various physiologically relevant macromolecules, including proteins. The insights gained from designing these artificial molecular sieves and filters, along with the promising results gathered from their first applications, serve to illustrate the impact that they can have on improving future separation of complex biological samples. Further development of artificial sieves and filters with more elaborate geometrical constraints and tailored surface functionality is believed to provide more promising ideals and results for biomolecule separation, which has great implications for proteomic research and biomarker discovery.     

草坪蒸散研究进展

草坪蒸散量是指导草坪合理灌溉的重要指标。自20世纪中叶以来,以节水为目的的草坪蒸散研究越来越受到人们的重视。草坪蒸散研究的内容主要包括相互关联的3个方面：草坪蒸散率的测定与比较,草坪蒸散机制的研究和草坪节水灌溉的研究。草坪蒸散率在不同草种间存在不同程度的差异。暖季型草坪草和冷季型草坪草相比普遍具有较低的草坪蒸散率。暖季型草坪草的夏季日平均最大蒸散率为3.0-9.0mm,而冷季型草坪草的为3.6-12.6mm。密度大,生长缓慢的杂交狗牙根、结缕草、野牛草和假俭草的耗水量很低,细羊茅的耗水量中等,而草地早熟禾、高羊茅、1年生早熟禾和匍匐剪股颖的耗水量很大。同种草坪草的不同品种的草坪蒸散率存在差异。有些草种内品种间差异的程度高达64％,不亚于种间。冷季型草坪草品种的蒸散率与留茬量显著相关,但环境因子对品种的蒸散率影响很大,品种的蒸散特性不稳定。与冷季型草坪草相比,暖季型草坪草的种内品种间蒸散率的差异和谐较小。草坪的冠层是草坪蒸散的一个主要外部条件,具有较低蒸散率的草坪往往具备高冠层阻力和低叶面积。土壤水分不受限制时,不同的暖季型草坪草种间的草坪蒸散率与叶片背面的气孔密度显著负相关。但在种内品种间没有表现出相关性。冷季型草坪草种间和种内的叶片气孔数目和草坪的蒸散率不相关。草坪的作物系数是确定最适灌溉量的关键参数,线性梯度灌溉系统比小型蒸渗仪提供的草坪作物系数更接近于实际。当草坪的质量维持在可接受的水平时,以彭曼公式推测的苜蓿的潜在蒸散量为参照蒸散量,高羊茅草坪的作物系数为0.60-0.80,草地早熟禾草坪的作物系数为0.50-0.80。基于草坪冠层温度的作物水分胁迫系数（CWSI）是确定灌溉时机的比较合理的指标。CWSI在不同的季节和不同的草种间表现不稳定,并且这种方法的节水效果也表现不一,还处于发展阶段。草坪蒸散的研究在我国几乎处于空白状态,开展我国的草坪蒸散研究,寻求适合的草坪节水途径已势在必行。     

Paracentric inversions: a review

This review of paracentric inversions in man includes what we know of the behaviour and reproductive consequences of paracentric inversions from other species. Observations of naturally occurring inversions in several species of plants and animals and results of experiments with mutagenically induced inversions in the mouse are discussed. From a review of 184 cases, it is concluded that most of the paracentric inversions in man are harmless and that the risk of heterozygotes having a child with an unbalanced karyotype is low. However, in some cases, it is difficult, if not impossible, to distinguish between a paracentric inversion and a paracentric insertion, the risk in the latter case being about 15%. Caution is also necessary in interpreting the results of prenatal diagnosis for heterozygotes of paracentric inversions, because of the possibility of a variety of unpredictable unbalanced chromosome products.     

Selachian cytogenetics: a review

The karyotype of Chondrichthyes is still the least investigated among vertebrates. Over the last 40 years, the karyotypes of 63 out of the 1100 known species (5.73%) have been described in literature, namely seven squalomorph, one squatinomorph, 20 galeomorph, 33 batoid and two holocephalian species. Generally, the diploid number ranges from a minimum of 28 to a maximum of 106 elements, with more frequent values observed between 50 and 100 chromosomes. None of the four superorders is characterized by a peculiar chromosome set or morphology; the number of uniarmed and biarmed elements is variable in all the karyotypes, and microchromosomes are often present. The general trend in all groups seems to be a progressive reduction of the telocentric chromosome number in the most specialized species, followed by the loss of the microchromosomes. Polyploidy, followed by diploidization events and Robertsonian rearrangements, might have played a key role in the karyological evolution of elasmobranch fish. Chondrichthyes have the largest genome sizes among vertebrates, with the exception of dipnoans and urodeles. In the whole class, the species examined vary greatly in size, from 3 to 34pg/N: the lowest values have been observed in holocephalians, while galeoids and batoids have a DNA amount ranging from 5 to 15 pg/N. Squaloids show heterogeneous DNA amounts, ranging from 8 to 34 pg/N. In more recent years, karyological studies have provided new data on the characterization of selachian karyotypes by C-banding, NOR staining, restriction enzymes in situ digestion and FISH with specific DNA probes, such as telomeric and SINE sequences.     

Alport syndrome: a review

Alport syndrome, a hereditary nephritis accompanied by high-tone sensorineural deafness and distinctive ocular signs was first noted in the literature during the early 1900s. This disease is caused by a genetic defect in Type IV collagen which makes up basement membranes in many body systems. The patient will usually have bilateral anterior lenticonus causing varied refractive errors. You may also note yellow-white to silver flecks within the macular and midperipheral regions of the retina. The treatment of the visual problems is an important but secondary concern due to the seriousness of the systemic disease. Dual sensory loss, however, creates an urgent need for appropriate vision care. Due to the high risk for developmental delay and decreased social integration, early intervention should be considered in the treatment plan. Coping strategies for the patient (and the family) need to be addressed because of the chronicity of this syndrome. The primary care optometrist will be challenged by the individual with Alport syndrome since a balance between oculo-visual, developmental/psycho-educational and systemic care is required. A multi-disciplinary approach by the healthcare management team will enhance the quality of life and positive outcomes for these patients.     

Invertebrate aquaporins: a review

Aquaporins (AQPs) or water channels render the lipid bilayer of cell membranes permeable to water. The numerous AQP subtypes present in any given species, the transport properties of each subtype and the variety of methods of their regulation allows different cell types to be transiently or permanently permeable to water or other solutes that AQPs are capable of transporting (e.g. urea or glycerol). AQPs have been well characterized in all vertebrate classes, other than reptilia. Here we review the current state of knowledge of invertebrate AQPs set in the context of the much more thoroughly studied vertebrate AQPs. By phylogenetic analysis of the total AQP complement of several completed insect genomes, we propose a classification system of insect AQPs including three sub-families (DRIP, BIB and PRIP) that have one representative from all the complete insect genomes. The physiological role of AQPs in invertebrates (insects, ticks and nematodes) is discussed, including their function in common invertebrate phenomena such as high-volume liquid diets, cryoprotection and anhydrobiosis.     

Mannosylerythritol lipids: a review

Mannosylerythritol lipids (MELs) are surface active compounds that belong to the glycolipid class of biosurfactants (BSs). MELs are produced by Pseudozyma sp. as a major component while Ustilago sp. produces them as a minor component. Although MELs have been known for over five decades, they recently regained attention due to their environmental compatibility, mild production conditions, structural diversity, self-assembling properties and versatile biochemical functions. In this review, the MEL producing microorganisms, the production conditions, their applications, their diverse structures and self-assembling properties are discussed. The biosynthetic pathways and the regulatory mechanisms involved in the production of MEL are also explained here.     

Megakaryocyte endomitosis: a review

During the early stages of their differentiation, megakaryocytes become polyploid through repeated DNA replication and endomitotic cycles without cytokinesis. The molecular basis for the process of polyploidization remains unknown. This review summarizes available information on the cell biology of the process of endomitosis.     

African histoplasmosis: a review

African histoplasmosis caused by Histoplasma capsulatum var. duboisii is an important deep mycosis endemic in Central and West Africa and in the island of Madagascar. The disease is characterized by presence of granulomatous lesions in the skin, subcutaneous tissues and bones. Lungs and other internal organs are rarely involved. The natural reservoir of the etiological agent has only been recently discovered in a bat cave in Nigeria. The status of asymptomatic infection is not certain. Investigations on skin and serum reactivity have suggested frequent prevalence of asymptomatic infections due to H. capsulatum var. duboisii among the residents in the vicinity of the cave microfocus of the fungus. The exact portal of entry into the body is not known, but inhalation into the lungs and direct inoculation in the skin have been incriminated. Laboratory diagnosis is confirmed by in vitro conversion into large yeast forms (8-15 mum in diameter) and by the demonstration of these forms within giant cells of tissues of experimentally infected animals There are no major clean-cut physiological differences between the two varieties, viz. capsulatum and duboisii. The cell wall of H. capsulatum var duboisii contains a glucan with beta 1-4 linkages in addition to a galactomannan shared with H. capsulatum var. capsulatum. Like the var. capsulatum var. duboisii has marked proteinase and collagenase activities in both mycelial and yeast forms, suggesting a possible pathogenic role for these enzymes. Both varieties have a common exoantigen. The yeast form of H. capsulatum var. duboisii contains the antigen found in the serotype 1,4 of var. capsulatum. A monoclonal antibody test has been developed that can recognize some epitopes in H. capsulatum var. capsulatum but not in the var. duboisii. There is need to develop specific serological diagnosis for the disease. Also there should be greater international awareness about African histoplasmosis. Amphotericin B and several antimycotic azoles like ketoconazole, itraconazole and fluconazole have been successfully employed for treatment.     

Salmonid inbreeding: a review

We review the published literature oninbreeding and its consequences in salmonidfishes. Inbreeding reduces genetic variationwithin populations by decreasingheterozygosity, either through an increasedchance of sharing parental genes or a loss ofalleles from random genetic drift. Increasedinbreeding is often associated with a reductionin mean phenotypic value of one or more traitswith respect to fitness (inbreedingdepression). We identify several sources ofinbreeding in salmonids. Although inbreedingoccurs naturally, much of the evidence forinbreeding stems from direct or indirectresults of human activity. The potentialconsequences of inbreeding highlight theimportance of maintaining genetic diversity insalmonid populations. Our weak understandingof genetic interactions between cultured andwild salmonids has allowed widespread practicesthat can reduce genetic variability in naturalpopulations. Although studies have detectedinbreeding depression in salmonids, its geneticbasis has rarely been addressed in wild,anadromous salmon. The genetic basis ofinbreeding depression is complex, andevaluating its effects over the entire lifecycle remains challenging. The experimentalevidence nevertheless reinforces the importanceof maintaining genetic variation withinpopulations as a primary goal of conservationand management.

     

寡核苷酸药物及寡核苷酸制备技术研究进展

寡核苷酸是生物医学和生命科学研究中调节基因表达的基本工具,并被开发为基因靶向治疗药物,用于治疗病毒、肿瘤和遗传病。寡核苷酸药物主要包括反义寡核苷酸、小干扰RNA、核酶、脱氧核酶、反基因、Cp G寡核苷酸、转录因子诱饵和核酸适配体等。天然的寡核苷酸在体内很容易被降解,特异性低,且有毒副作用。因此,药物寡核苷酸通常带有特定的修饰基团,如硫代磷酸二酯键、氟代、甲基以及锁核酸等,以增强寡核苷酸在体内的稳定性,提高特异性,并降低其毒副作用。目前,寡核苷酸主要采用化学方法合成,但化学合成的寡核苷酸初产物纯度低,而纯化十分困难。大规模核酸合成仪和纯化设备十分昂贵,因而大量合成和纯化寡核苷酸的成本高昂,大大限制了寡核苷酸药物的研究和应用。尽管已经涌现了多种多样的核酸扩增和检测方法,但用于扩增寡核苷酸的方法极少,且均不适合大量制备寡核苷酸。一种新的基于热循环的寡核苷酸扩增方法,称为"聚合酶-内切酶扩增反应"(Polymerase-endonuclease amplification reaction,PEAR),能够使寡核苷酸等小分子核酸在双酶催化下,利用独特的"滑动-切割机制"进行自我复制,并实现指数扩增。PEAR反应简单、高效、稳定。该方法已成功制备硫代和氟代修饰的寡核苷酸,与化学合成法相比,该技术不依赖于大规模DNA合成仪,降低了生产成本,适合大量生产高纯度的寡核苷酸,将有助于推动寡核苷酸药物的研究和应用。