60 research outputs found

    Variations in the formation of the median nerve and its clinical correlation

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    Variations in the formation of the median nerve are of interest to anatomists, radiologists, and surgeons. These variations may be vulnerable to damage in surgical operations, but their knowledge also helps in the interpretation of a nervous compression having unexplained clinical symptoms. We studied the variation in the formation of the median nerve in 87 cadavers, i.e. 174 upper limbs of formalin preserved cadavers at the department of Anatomy, Subharti medical college. We observed an additional root taking part in the formation of the median nerve in 26.4% of upper limbs, unusual low formation of the median nerve in the arm in front of the brachial artery in 18.4% of upper limbs, and median nerve formation medial to the axillary artery in 10.3% of upper limbs. Knowledge of such anatomical variations is of interest to the anatomist and clinician alike. Surgeons who perform procedures involving neoplasm or trauma repair need to be aware of these variations

    Variant origin of superior polar artery and unusual hilar branching pattern of renal artery with clinical correlation

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    Classically, a single renal artery arising from the abdominal aorta supplies the respective kidney on each side. Near the hilum of the kidney each renal artery divides into anterior and posterior branchs, which in turn divide into segmental arteries supplying the different renal segments. A total of 84 formalin fixed cadavers (73 male and 11 female, 168 kidneys in total) constituted the material for the study. During routine abdominal dissection conducted for medical undergraduates, the kidneys and their arteries were explored and variations in morphological patterns of renal arteries were noted. We observed superior polar renal artery in 22.6% cases. Superior polar renal arteries had different sources of origin. In 10.7% of cases it came directly from the abdominal aorta as an accessory renal artery; in 5.4% of cases as a direct branch from the main renal artery; in 3.6% of cases from the superior hilar renal artery (from one of the duplicated renal arteries); and in 3.0% of cases from a segmental branch of the renal artery. We also observed unusual hilar branching patterns of renal arteries, which included a fork pattern in 11.3% of cases, ladder pattern in 7.7% of cases, net pattern in 5.9% of cases, and triplicate in 3.0% of cases. Understanding the anatomy of vascular variations of the kidney is essential for the clinician to be able to perform procedures such as renal transplantation, interventional radiological procedures, and renal vascular operations more safely and efficiently. (Folia Morphol 2011; 70, 1: 24-28

    Influence of Fabrication Technique on the Fiber Pushout Behavior in a Sapphire-Reinforced Nial Matrix Composite

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    Directional solidification (DS) of \u27\u27powder-cloth\u27\u27 (PC) processed sapphire-NiAl composites was carried out to examine the influence of fabrication technique on the fiber-matrix interfacial shear strength, measured using a fiber-pushout technique. The DS process replaced the fine, equiaxed NiAl grain structure of the PC composites with an oriented grain structure comprised of large columnar NiAl grains aligned parallel to the fiber axis, with fibers either completely engulfed within the NiAl grains or anchored at one to three grain boundaries. The load-displacement behavior during the pushout test exhibited an initial \u27\u27pseudoelastic\u27\u27 response, followed by an \u27\u27inelastic\u27\u27 response, and finally a \u27\u27frictional\u27\u27 sliding response. The fiber-matrix interfacial shear strength and the fracture behavior during fiber pushout were investigated using an interrupted pushout test and fractography, as functions of specimen thickness (240 to 730 mu m) and fabrication technique. The composites fabricated using the PC and the DS techniques had different matrix and interface structures and appreciably different interfacial shear strengths. In the DS composites, where the fiber-matrix interfaces were identical for all the fibers, the interfacial debond shear stresses were larger for the fibers embedded completely within the NiAl grains and smaller for the fibers anchored at a few grain boundaries. The matrix grain boundaries coincident on sapphire fibers were observed to be the preferred sites for crack formation and propagation. While the frictional sliding stress appeared to be independent of the fabrication technique, the interfacial debond shear stresses were larger for the DS composites compared to the PC composites. The study highlights the potential of the DS technique to grow single-crystal NiAl matrix composites reinforced with sapphire fibers, with fiber-matrix interfacial shear strength appreciably greater than that attainable by the current solid-state fabrication techniques

    How to perform gastrointestinal ultrasound: Anatomy and normal findings

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    Gastrointestinal ultrasound is a practical, safe, cheap and reproducible diagnostic tool in inflammatory bowel disease gaining global prominence amongst clinicians. Understanding the embryological processes of the intestinal tract assists in the interpretation of abnormal sonographic findings. In general terms, the examination principally comprises interrogation of the colon, mesentery and small intestine using both lowfrequency and high-frequency probes. Interpretation of findings on GIUS includes assessment of bowel wall thickness, symmetry of this thickness, evidence of transmural changes, assessment of vascularity using Doppler imaging and assessment of other specific features including lymph nodes, mesentery and luminal motility. In addition to B-mode imaging, transperineal ultrasonography, elastography and contrast-enhanced ultrasonography are useful adjuncts. This supplement expands upon these features in more depth

    Processing of aluminum-graphite particulate metal matrix composites by advanced shear technology

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    Copyright @ 2009 ASM International. This paper was published in Journal of Materials Engineering and Performance 18(9) and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.To extend the possibilities of using aluminum/graphite composites as structural materials, a novel process is developed. The conventional methods often produce agglomerated structures exhibiting lower strength and ductility. To overcome the cohesive force of the agglomerates, a melt conditioned high-pressure die casting (MC-HPDC) process innovatively adapts the well-established, high-shear dispersive mixing action of a twin screw mechanism. The distribution of particles and properties of composites are quantitatively evaluated. The adopted rheo process significantly improved the distribution of the reinforcement in the matrix with a strong interfacial bond between the two. A good combination of improved ultimate tensile strength (UTS) and tensile elongation (e) is obtained compared with composites produced by conventional processes.EPSR

    New insights into the genetic etiology of Alzheimer's disease and related dementias

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    Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

    Bryophyte Diversity in Mukteshwar (Uttarakhand): an overview

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    The present study deals with the investigation of bryophytic flora of Mukteshwar (Uttarakhand). The present account deals with the study of 38 species belonging to 31 genera of 21 families. The mosses are represented by 21 species of 20 genera and 12 families, while Liverworts are represented by 15 species of 10 genera and 8 families. Hornworts consist of 1 genus and 2 species. The dominant families are Aytoniaceae, Marchantiaceae, Thuidiaceae and Pottiaceae. The dominant genera are Plagiochasma, Targionia, Marchantia, Plagiochila, Atrichum, Thuidium and Pogonatum. Macrothamnium stigmatophyllum has been identified as new to western Himalaya, while Thuidium philiberti Limpr. is new to Uttarakhand

    Transperineal Ultrasound for Perianal Fistulas and Abscesses : A Systematic Review and Meta-Analysis

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    Purpose Transperineal ultrasound (TPUS) is a practical tool for assessing perianal inflammatory lesions. We systematically review its accuracy for detecting and classifying perianal fistulae and abscesses. Method The National Library of Medicine and Embase were searched for articles on TPUS for the assessment of idiopathic and Crohn's perianal fistulae and abscesses. Two reviewers independently reviewed eligible studies and rated them for quality using the QUADAS tool. The primary outcome measure was the accuracy of TPUS as measured by its sensitivity and positive predictive value (PPV) in detecting and classifying perianal fistulae, internal openings and perianal abscesses. Results We included 12 studies (565 patients). Overall, the methodological quality of the studies was suboptimal. 3 studies were retrospective and 4 showed significant risks of bias in the application of the reference standard. The sensitivity of TPUS in detecting perianal fistulae on a per-lesion basis was 98 (95 CI 96-100) and the PPV was 95 (95 CI 90-98). The detection of internal openings had a sensitivity of 91 (95 CI 84-97) with a PPV of 87 (95 CI 76-95). The classification of fistulae yielded a sensitivity of 92 (95 CI 85-97) and a PPV of 92 (95 CI 83-98). TPUS had a sensitivity of 86 (95 CI 67-99) and PPV of 90 (95 CI 76-99) in the detection of perianal abscesses. Conclusion The current literature on TPUS illustrates good overall accuracy in the assessment of perianal fistulae and abscesses. However, many studies had methodological flaws suggesting that further research is required
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