流固耦合作用下真实人体上呼吸道呼吸流涡结构演化的数值仿真

通过构建真实人体上呼吸道三维规范模型,运用大涡模拟数值方法,对考虑流固耦合作用的低强度循环呼吸模式下人体上呼吸道内的呼吸流进行了数值仿真,研究分析了人体口喉模型及气管支气管内的气流涡结构及其演化过程。结果表明,循环吸气过程中,气流在口腔中部以及舌苔上部形成多个涡管,在声门部位形成强烈的射流,在气管前壁出现马蹄涡,到气管中部大尺度涡结构逐步消失,支气管中只剩下一系列小尺度涡结构;循环呼气过程中,气流在气管底部产生较为复杂的涡结构,随着气流在气管内的融合,涡强度逐步减弱,在咽喉后壁形成拱状涡,气流进入口腔后,涡结构破裂,涡量扩散,没有较大的涡结构产生。     

Structural and ultrastructural characterization of male reproductive tracts and spermatozoa in fig wasps of the genus Pegoscapus (Hymenoptera, Chalcidoidea)

The three Pegoscapus species present the same internal reproductive tract features comprising testes with a single testicular tubule, seminal vesicles, vasa deferentia, accessory glands and an ejaculatory duct. The seminal vesicle shows two morphologically distinct portions although they do not resemble the separate chambers found in other Chalcidoidea. The anterior portion of the seminal vesicle shows a prominent epithelium and stores the mature spermatozoa, while the posterior region is formed by a thicker muscular sheath that participates on ejaculation. The sexual maturation in Pegoscapus is achieved at emergence, when the testicular degeneration occurs. The spermatozoa of Pegoscapus reveal a basic structure similar to that of other Chalcidoidea. In Pegoscapus sp1. and Pegoscapus sp2. they present the same features, whereas Pegoscapus tonduzi comprises some different characteristics. It measures approximately 160 μm in Pegoscapus sp1. and Pegoscapus sp2., while in P. tonduzi the spermatozoa measure about 360 μm. The extracellular sheath thickness is another difference among the species. While Pegoscapus sp1. and Pegoscapus sp2. show a thick extracellular sheath, in P. tonduzi this sheath is very thin resulting in a large space intervening between the extracellular sheath and the nucleus. Despite these differences, the three species analyzed share some characteristics that allow the establishment of an identity to the spermatozoon of the genus Pegoscapus: the seminal vesicle not divided in chambers; the absence of acrosomal structures in the spermatozoa; the length of the extracellular sheath; the central microtubules being the firsts to terminate in the sequence of microtubular cutoff at the final axonemal portion.     

山溪鲵消化系统组织学的初步研究

采用常规石蜡切片和扫描电镜,观察了山溪鲵消化系统组织结构和粘膜表面.结果表明,除口腔外,消化道管壁由粘膜层、粘膜下层、肌层和浆膜构成.消化道各部分的差别主要在粘膜层和肌层:食道粘膜为复层柱状上皮,无纵肌层;胃、肠粘膜上皮为单层柱状上皮,胃肠肌层有内环外纵两层平滑肌组成.而且粘膜上皮细胞表面细微结构、粘膜中腺体的分布情况、肌层的相对厚度等在消化道各部分也存在差异.肝细胞以群集为主,肝小叶不明显,胰为弥散型.     

The Impact of Selected Essential Oils Applied to Non-Woven Viscose on Bacteria That Cause Lower Urinary Tract Infections—Preliminary Studies

Inflammation of the lower urinary tract is a very common problem, which occurs particularly in women. A concept of a biotextronics system for preventive and support treatment of lower urinary tract inflammations was presented. The system includes a non-woven viscose insert for essential oils application. The oils were deposited on the non-woven viscose and incubated in the temperature of 37 °C and served a model for their action in the vapor phase as the element of the biotextronics system. The essential oils used in the research were the following: chamomile (Matricaria chamomilla L.), sage (Salvia officinalis L. and Salvia lavandulaefolia), juniper (Juniperus communis L.), thyme (Thymus vulgaris L.), and mixtures of chamomile oil with oils of each sage species in a 1:1 ratio. The oils were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Staphylococcus saprophyticus, and Enterococcus faecalis. The best inhibitory effect in vapor phase was noted for chamomile essential oil at the lowest concentration (0.054 µL/cm³). Both mixtures of chamomile and sage acted antagonistically, lowering the antibacterial activity of the individual oils applied solely. Juniper and Salvia officinalis essential oils at the concentrations tested increased the growth of at least one of the bacteria tested. Salvia lavandulaefolia Vahl. essential oil inhibited all bacteria, only at the concentration 0.214 µL/cm³. The thyme oil, at the concentration 0.054 µL/cm³, reduced the growth of all bacterial species tested. Chamomile and thyme essential oils were chosen for further research in the biotextronics pantiliner system.     

Evaluating Efficacy of Antimicrobial and Antifouling Materials for Urinary Tract Medical Devices: Challenges and Recommendations

In Europe, the mean incidence of urinary tract infections in intensive care units is 1.1 per 1000 patient‐days. Of these cases, catheter‐associated urinary tract infections (CAUTI) account for 98%. In total, CAUTI in hospitals is estimated to give additional health‐care costs of £1–2.5 billion in the United Kingdom alone. This is in sharp contrast to the low cost of urinary catheters and emphasizes the need for innovative products that reduce the incidence rate of CAUTI. Ureteral stents and other urinary‐tract devices suffer similar problems. Antimicrobial strategies are being developed, however, the evaluation of their efficacy is very challenging. This review aims to provide considerations and recommendations covering all relevant aspects of antimicrobial material testing, including surface characterization, biocompatibility, cytotoxicity, in vitro and in vivo tests, microbial strain selection, and hydrodynamic conditions, all in the perspective of complying to the complex pathology of device‐associated urinary tract infection. The recommendations should be on the basis of standard assays to be developed which would enable comparisons of results obtained in different research labs both in industry and in academia, as well as provide industry and academia with tools to assess the antimicrobial properties for urinary tract devices in a reliable way.     

Fish oil based vitamin D nanoencapsulation by ultrasonication and bioaccessibility analysis in simulated gastro-intestinal tract

Recently, nanoemulsions have been employed for different applications including food and drug industries for efficient nutrient delivery system. In this study, vitamin D (a lipophilic molecule) was encapsulated in fish oil for higher oral bioavailability. The oil-in-water nanoemulsion was formulated by ultrasonication technique with a droplet size range of 300–450 nm and a shelf life of more than 90 days. The influence of oil, water and surfactant concentration was investigated by phase diagram. The formulated nanoemulsion had encapsulation efficiency in the range of 95.7–98.2%. Further, nanoemulsion passed through simulated gastro-intestinal tract revealed an increased bioavailability than non-encapsulated vitamin. Thus, the formulation can be used as a drug delivery vehicle for various lipophilic compounds. Till date, no one have fabricated an efficient nano-vehicle for the delivery of vitamin D as well as analyzed the efficient delivery system in simulated GI-tract, this is first of its kind study in this regard. This can be scaled up further after analyzing the safety aspects.     

Antimicrobial performance of nanostructured silica–titania sieves loaded with izohidrafural against microbial strains isolated from urinary tract infections

This study aimed to examine the efficiency of novel bioactive nanostructures represented by silica–titania sieves used as carriers for a new antibacterial agent izohidrafural against bacterial strains isolated from nosocomial urinary tract infections, by using biological quantitative assays. Several release trials have been established and compared with MCM-41 in parallel experiments to achieve the optimum release profile. The obtained systems showed that silica–titania sieves loaded with izohidrafural proved to be the most active material against Klebsiella pneumoniae (average minimal inhibitory concentration [MIC] 40.62 μg/mL), desaminase-positive strains (average MIC 2.925 μg/mL), and Proteus mirabilis (average MIC 9.37 μg/mL), the last being reported with the highest growth rate in the urinary tract catheters. In contrast, the nonloaded silica–titanium sieves exhibited the highest antimicrobial activity against the Gram-positive cocci. Izohidrafural exhibited the highest antimicrobial efficiency, superior to the common drug nitrofurantoin against most Escherichia coli strains, with average MIC of 4.68 μg/mL.     

What causes the hyperintense T2-weighting and increased short T2 signal in the corticospinal tract?

The corticospinal tract (CST) appears hyperintense on both T₂-weighted images and myelin water maps. Here, an extended multiecho T₂ relaxation sequence with echoes out to 1120 ms was used to characterize the longer T₂ times present in the CST. The T₂ distribution from the CST was compared to other white matter structures in 14 healthy subjects. The intra-/extracellular T₂ peak of the CST was broadened relative to other white matter structures and often split into two distinct peaks. In the CST, it appeared that the intracellular and extracellular water environments had unique T₂ times, causing the intracellular water peak to be pushed down into the myelin water T₂ regime and the extracellular peak to be pushed up to longer T₂ times. The conventional myelin water T₂ limits of 5-40 ms resulted in an artificial increase in myelin water fraction (MWF), causing the CST to be bright on myelin water images. When the upper limit for MWF was decreased to 25 ms, the CST regions exhibited MWF values similar to those found for adjacent anterior and posterior regions. The CST has unique magnetic resonance characteristics, which should be taken into consideration when being examined, especially when compared to pathological tissue.     

Mathematical models in urinary system mechanics (review)

The problems of theoretical biomechanical studies of the urine formation and excretion system (urinary system), from renal filtration to urine motion in the urethra, are reviewed.__________Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, 2005, pp. 3–23. Original Russian Text Copyright © 2005 by Bykova and Regirer.