838 research outputs found

    Structural and molecular characteristics of axons in the long head of the biceps tendon

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    The innervation of the long head of the biceps tendon (LHBT) is not sufficiently documented. This is a drawback since pathologies of the LHBT are a major source of shoulder pain. Thus, the study aimed to characterize structurally and molecularly nervous elements of the LHBT. The proximal part of 11 LHBTs was harvested intraoperatively. There were 8 female and 3 male specimens. Age ranged from 66 to 86 years. For structural analyses, nervous elements were viewed in the transmission electron microscope. For molecular characterization, we used general neuronal markers including antibodies against neurofilament and protein gene product 9.5 (PGP9.5) as well as specific neuronal markers including antibodies against myelin basic protein (MBP), calcitonin gene-related product (CGRP), substance P (SP), tyrosine hydroxylase (TH), and growth-associated protein 43 (GAP43). Anti-neurofilament and anti-PGP9.5 visualized the overall innervation. Anti-MBP visualized myelination, anti-CGRP and anti-SP nociceptive fibers, anti-TH sympathetic nerve fibers, and anti-GAP43 nerve fibers during development and regeneration. Immunolabeled sections were analyzed in the confocal laser scanning microscope. We show that the LHBT contains unmyelinated as well as myelinated nerve fibers which group in nerve fascicles and follow blood vessels. Manny myelinated and unmyelinated axons exhibit molecular features of nociceptive nerve fibers. Another subpopulation of unmyelinated axons exhibits molecular characteristics of sympathetic nerve fibers. Unmyelinated sympathetic fibers and unmyelinated nociceptive fibers express proteins that are found during development and regeneration. Present findings support the hypothesis that ingrowth of nociceptive fibers are the source of chronic tendon pain

    New Salamanders (Caudata: Plethodontidae) From Guatemala, with Miscellaneous Notes on Known Species

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    New salamanders in the genera Bolitoglossa and Dendrotriton are described from the highlands of Guatemala. These species are distinguished from their congeners by morphology and molecular differences, including elements of color pattern. These new species of salamanders were collected over the last 30 years, and for many of them the localities of some of these new species are now badly degradedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111063/1/MP200.pd

    Xenopus fraseri: Mr. Fraser, where did your frog come from?

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    A comprehensive, accurate, and revisable alpha taxonomy is crucial for biodiversity studies, but is challenging when data from reference specimens are difficult to collect or observe. However, recent technological advances can overcome some of these challenges. To illustrate this, we used modern approaches to tackle a centuries-old taxonomic enigma presented by Fraser’s Clawed Frog, Xenopus fraseri, including whether X. fraseri is different from other species, and if so, where it is situated geographically and phylogenetically. To facilitate these inferences, we used high-resolution techniques to examine morphological variation, and we generated and analyzed complete mitochondrial genome sequences from all Xenopus species, including >150-year-old type specimens. Our results demonstrate that X. fraseri is indeed distinct from other species, firmly place this species within a phylogenetic context, and identify its minimal geographic distribution in northern Ghana and northern Cameroon. These data also permit novel phylogenetic resolution into this intensively studied and biomedically important group. Xenopus fraseri was formerly thought to be a rainforest endemic placed alongside species in the amieti species group; in fact this species occurs in arid habitat on the borderlands of the Sahel, and is the smallest member of the muelleri species group. This study illustrates that the taxonomic enigma of Fraser’s frog was a combined consequence of sparse collection records, interspecies conservation and intraspecific polymorphism in external anatomy, and type specimens with unusual morphology

    Coulomb-Driven Cluster-Glass Behavior in Mn-Intercalated Ti1+yS2

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    We have investigated the low-temperature spin-glasslike phase in the intercalated transition-metal dichalcogenide Mn0.09Ti1.1S2. A departure from Curie–Weiss behavior in the paramagnetic regime indicated the formation of small ferromagnetically correlated clusters. The Vogel–Fulcher law provided an excellent description of relaxation times in the vicinity of the transition, showing that the glasslike phase occurs due to interaction between the clusters. Cole–Cole plots for data close to the transition were linear, which is consistent with a simple exponential distribution of cluster sizes. A Monte Carlo simulation of the dichalcogenide system, including excess self-intercalated Ti ions, gave an exponential cluster-size distribution for a relatively narrow range of concentration values of Mn and Ti ions, values that were consistent with those of the Mn0.09Ti1.1S2 sample. Strong commonality in the relaxation behavior with certain ferroelectric relaxor systems suggests underlying similarity in the microscopic structure of the clusters in both systems, which may be chainlike or quasi-one-dimensional

    Diversity of Mycobacterium tuberculosis strains in Nairobi, Kenya

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    Setting: Tuberculosis (TB) patients attending 16 public health facilities in Nairobi, Kenya. Objective: To determine the Mycobacterium tuberculosis (M.tuberculosis) strain families circulating in Nairobi, Kenya. Methods: Sputum specimens from consecutive new and previously treated smear positive pulmonary TB patients were collected between February and August 2010 and cultured on Lowenstein9Jensen media. Spoligotyping was done on DNA extracted from the first isolate of each patient. The international spoligotype data base (SpolDB4) was used to group isolates into strain families. Results: Fourty seven different strain families were identified from 536 isolates. The principal groups were; CAS1_KILI 96/536 (17%), T1 69/536 (12%), Beijing 65/536 (12%), LAM9 46/536 (9% ), LAM3 & S/Conversant 37/536 (7% ), LAM11_ZWE 26/536 (5%), CAS1_DELHI 24/536 (4%) and T2 24/536 (4%). Others identified and are found in the SpolDB4 were 113/536 (21%). A possible new M.tuberculosis strain family was identified with 21/536 (4%) isolates which was designated as Nairobi subtype. Others identified not previously included in the SpolDB4 accounted for 15/536 (3%). Conclusion: We found a diverse array of M.tuberculosis strain families which could be indicative of a cosmopolitant polulation with frequent migration that may suggest that the dorminant strain families may have been present in the population for an extended period of time or on going transmision of closely related strains families. The emergence of the Beijing strains poses a serious threat to TB control due to its high virulence and frequent association with multidrug resistance. We therefore call for strenghthening efforts on early case finding through enhanced public health education campains and provision of accessible diagnostic services with enhanced treatment compliance

    Existential witness extraction in classical realizability and via a negative translation

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    We show how to extract existential witnesses from classical proofs using Krivine's classical realizability---where classical proofs are interpreted as lambda-terms with the call/cc control operator. We first recall the basic framework of classical realizability (in classical second-order arithmetic) and show how to extend it with primitive numerals for faster computations. Then we show how to perform witness extraction in this framework, by discussing several techniques depending on the shape of the existential formula. In particular, we show that in the Sigma01-case, Krivine's witness extraction method reduces to Friedman's through a well-suited negative translation to intuitionistic second-order arithmetic. Finally we discuss the advantages of using call/cc rather than a negative translation, especially from the point of view of an implementation.Comment: 52 pages. Accepted in Logical Methods for Computer Science (LMCS), 201
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