Monoliths with chiral surface functionalization for enantioselective capillary electrochromatography

The state-of-the-art in CEC enantiomer separations with monolithic capillary columns is comprehensively reviewed. The various types of monolithic columns comprising in situ organic polymer monoliths, molecularly imprinted polymer (MIP) monoliths, silica monoliths and monoliths made from particles are discussed with a focus on materials’ synthesis, chemistry and properties as well as column aspects. Monolithic MIP-type porous layer open-tubular (PLOT) columns are treated herein as well. From this survey of the literature, the authors come to the conclusion that monolithic silica capillaries appear to become the preferred column type for CEC enantiomer separations of low-molecular drugs and other chiral pharmaceuticals or chemicals.     

不同树脂牙耐磨性和硬度的比较研究

目的 通过对7种常用的树脂牙进行硬度和耐磨性的比较研究，为临床修复牙列缺损缺失时人工牙的选择提供理论基础。 方法 选择七种不同树脂牙,它们分别为硬质复色合成树脂牙(A)、复色合成树脂牙(B)、合成树脂牙(C)、ENDURA塑钢牙(D)、三层色合成树脂牙(E)、Optostar四层色合成树脂牙(F)、CosmosHXL(G)。用销-盘式摩擦磨损试验机进行磨耗试验，用磨耗质量损耗及电镜观察比较这七种树脂牙的耐磨性能；采用努氏硬度法测试树脂亚的显微硬度。并研究树脂牙耐磨性和硬度之间的相关性。 结果 通过磨耗前后各树脂牙质量的损耗及电镜观察结果得出不同树脂牙耐磨性从高到低排列为：D>A>G>E>B>F>C；硬度测试结果是A：29.87±0.47 HK，B：22.63±0.70 HK，C：17.43±0.67 HK，D：41.24±1.71 HK，E：23.76±1.14 HK，F：23.02±1.44 HK，G：29.05±1.01 HK。树脂牙磨耗失重和硬度值的相关系数为－0.888（P<0.01）。 结论 材料组成成分、分子量和树脂牙加工工艺的差别可造成不同树脂牙硬度和耐磨性能之间的差异；不同树脂牙的硬度和耐磨性呈正相关。     

Relationship between solute transport properties and tissue morphology in human annulus fibrosus

Poor nutritional supply to the intervertebral disc is believed to be an important factor leading to disc degeneration. However, little is known regarding nutritional transport in human annulus fibrosus (AF) and its relation to tissue morphology. We hypothesized that solute diffusivity in human AF is anisotropic and inhomogeneous, and that transport behaviors are associated with tissue composition and structure. To test these hypotheses, we measured the direction‐dependent diffusivity of a fluorescent molecule (fluorescein, 332 Da) in three regions of AF using a fluorescence recovery after photobleaching (FRAP) technique, and associated transport results to the regional variation in water content and collagen architecture in the tissue. Diffusivity in AF was anisotropic, with higher values in the axial direction than in the radial direction for all regions investigated. The values of the diffusion coefficient ranged from 0.38 ± 0.25 × 10^?6 cm²/s (radial diffusivity in outer AF) to 2.68 ± 0.84 × 10^?6 cm²/s (axial diffusivity in inner AF). In both directions, diffusivity decreased moving from inner to outer AF. Tissue structure was investigated using both scanning electron microscopy and environmental scanning electron microscopy. A unique arrangement of microtubes was found in human AF. Furthermore, we also found that the density of these microtubes varied moving from inner to outer AF. A similar trend of regional variation was found for water content, with the highest value also measured in inner AF. Therefore, we concluded that a relationship exists among the anisotropic and inhomogeneous diffusion in human AF and the structure and composition of the tissue. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1625–1630, 2009     

念珠形发1例：附扫描电镜观察

２５岁男性，患念珠形发，无其他器官系统异常。头皮病理示毛囊稀疏，毛囊角化，有角栓形成。毛发扫描电镜示结节部尚存少量毛小皮，大部分毛小皮消失，狭窄处毛小皮消失，呈平行纵嵴，嵴间有沟，部分沟中有洞。口服维甲酸有效，提示发病可能与毛囊角化异常有关。     

The keratoconus epithelium studied by SEM

A keratoconus removed from an 18-year-old male was processed for SEM and examined with special attention for the epithelial surface. A broad degenerative band was found running in the vertical meridian, showing areas devoid of, or with only partially attached, epithelial cells, and also areas with abnormal cells either, with a defective cell membrane and without cell contents or with an intact cell membrane but without a cell nucleus. Stereoscopic images of these defective cells show that cell degeneration is sometimes found several cell layers deep into the epithelium.     

Vascular alterations in the canine kidney following obstruction of the urinary tract

Summary Changes in the vasculature of the canine kidney following four weeks obstruction of the ureter via double ligature is described on the basis of SEM investigation. Three significant alterations were observed: 1) A two-thirds reduction in the depth of the renal cortex as compared to controls. 2) Rarification of the entire cortical capillary bed. 3) Reduction in both the number and diameter of the glomeruli. The rarification of the post-glomerular capillaries is interpreted to be a pressure atrophy, whereas the reduction in the number of renal glomeruli and the concommitant diminuation of their capillary loops is thought to represent a functional atrophy.     

The identification of potential alternative biomarkers of nitrofurazone abuse in animal derived food products

Semicarbazide (SEM) was considered to be a characteristic protein-bound side-chain metabolite of the banned veterinary drug nitrofurazone and used as a marker of nitrofurazone abuse. It was recently discovered that SEM can arise in food from sources other than nitrofurazone. This uncertainty over the source of SEM may be overcome if alternative markers specific to tissue-bound nitrofurazone residues can be determined. The structure of nitrofurazone metabolites in vivo and particular proteins to which they are bound are not known. These proteins with altered structure due to the presence of the drug metabolites can be considered as potential alternative biomarkers of nitrofurazone abuse. The proteins implicated in the in vivo binding of nitrofurazone were separated and identified. A crude mixture of proteins extracted from the liver of a rat treated with the drug was separated using a series of different techniques such as preparative isoelectric focusing and size exclusion HPLC. Multiple fractions were assayed by LC-MS/MS to detect the presence of SEM. The proteins containing SEM residues were identified by peptide mass mapping using trypsin digestion and MALDI-TOF. The first protein identified as containing high concentration of SEM was albumin. It was also shown that low molecular weight species within a protein mixture whose main constituent was glutathione S-transferase contained a high concentration of SEM. The chemical composition of these components is under investigation. Preliminary data suggest the SEM forms part of a nitrofurazone metabolite conjugated to glutathione.     

Morphometric and molecular characterization of Parapharyngodon echinatus (Nematoda, Pharyngodonidae) from the Senegal gecko (Tarentola parvicarinata)

A West African species of gecko, Tarentola parvicarinata Joger (Gekkonidae), collected in the Niokolo Koba National Park in East Senegal is a new host species for the nematode Parapharyngodon echinatus (Rudolphi, 1819). Fifty one specimens of P. echinatus were studied under a light microscope and thirteen specimens were studied for the first time by a scanning electron microscope. The main differences between P. echinatus and other African species, especially Parapharyngodon micipsae (Seurat, 1917), were in the shape of annules on body cuticle, broad lateral alae and their terminations, the shape of the distal extremity of the spicule and number of outgrowths at the anterior cloacal lip. For the purposes of DNA characterization, partial sequence of the small subunit ribosomal RNA gene (SSU rRNA) was obtained from two specimens of P. echinatus. This is the first published sequence of a species from the family Pharyngodonidae.     

Morphometric and structural analysis of Florida manatee spermatozoa

Sperm characteristics, such as sperm morphology and sperm morphometry are important in assessing sperm quality. This is especially important for the management and conservation of endangered and exotic species, like the Florida manatee, where information of this nature is extremely limited. In this study, we fill this knowledge gap to better understand the reproductive physiology of Florida manatees by conducting the first extensive analysis of sperm morphometry and ultrastructure. Sperm were retrieved from the vas deferens of nine recently deceased Florida manatees. Computer-aided sperm morphology analysis (CASMA) was used for morphometric analysis and laser-scanning confocal microscopy and electron microscopy were used for structural and ultrastructural characterization. Our findings reveal new morphometric and structural data for the Florida manatee spermatozoon. Twelve morphometric features of Florida manatee sperm were quantified with some approximately 1.5–2 times larger than those previously reported. Ultrastructurally, the Florida manatee spermatozoon followed a mammalian structural pattern with an ovate-shaped head, midpiece containing 84–90 mitochondria, and a flagellum. However, unique ultrastructural features were identified. Distinct, rectangular-like enlargement of four outer dense fibers surrounding the axoneme was evident, which may provide additional tensile strength to counteract the forces on sperm transiting the female reproductive tract. Likewise, strong localization of F-actin fibers within the midpiece may function to maintain sperm integrity within the female reproductive tract. These findings highlight the potential effects of sexual selective pressures on sperm size and structure in the Florida manatee and provide avenues for research on the occurrence of sperm competition in this species.     

Evaluation of biofilm formation ability in different Candida strains and anti-biofilm effects of Fe3O4-NPs compared with Fluconazole: an in vitro study

Objective

Biofilm formation ability is one of the major virulence factors contributing to the pathogenesis of Candida species. Biofilms produced by Candida spp. cause complicated treatments and contribute to increasing unpleasant mortality rates. Nanoparticles of Fe₃O₄ (Fe₃O₄-NPs) are considered due to their magnetic and biochemical properties, as well as their low costs. The purpose of present study was to determine biofilm formation ability in different Candida strains and evaluation of anti-biofilm effect of Fe₃O₄-NPs compared with FLC.