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991.
Trevor A. Hart David M. Moore Syed W. Noor Nathan Lachowsky Daniel Grace Joseph Cox Shayna Skakoon-Sparling Jody Jollimore Abbie Parlette Allan Lal Herak Apelian Jordan M. Sang Darrell H. S. Tan Gilles Lambert the Engage Study Team 《Canadian journal of public health. Revue canadienne de santé publique》2021,112(6):1020
ObjectivesThe last Canadian biobehavioural surveillance study of HIV and other sexually transmitted and blood-borne infections (STBBI) among gay, bisexual and other men who have sex with men (GBM) was conducted in 2010. We designed a study to measure STBBI prevalence among GBM in metropolitan Montreal, Toronto and Vancouver and to document related preventive and risk behaviours.MethodsThe Engage Cohort Study used respondent-driven sampling (RDS) to recruit GBM who reported sex with another man in the past 6 months. At baseline, we examined recruitment characteristics of the samples, and the RDS-II-adjusted distributions of socio-demographics, laboratory-confirmed HIV and other STBBI prevalence, and related behaviours, with a focus on univariate differences among cities.ResultsA total of 2449 GBM were recruited from February 2017 to August 2019. HIV prevalence was lower in Montreal (14.2%) than in Toronto (22.2%) or Vancouver (20.4%). History of syphilis infection was similar across cities (14–16%). Vancouver had more HIV-negative/unknown participants who reported never being HIV tested (18.6%) than Toronto (12.9%) or Montreal (11.5%). Both Montreal (74.9%) and Vancouver (78.8%) had higher proportions of men who tested for another STBBI in the past 6 months than Toronto (67.4%). Vancouver had a higher proportion of men who used pre-exposure prophylaxis (PrEP) in the past 6 months (18.9%) than Toronto (11.1%) or Montreal (9.6%).ConclusionThe three largest cities of Canada differed in HIV prevalence, STBBI testing and PrEP use among GBM. Our findings also suggest the need for scale-up of both PrEP and STI testing among GBM in Canada. 相似文献
992.
A field-focusing device to increase power output of ThermoRod trade mark implants for thermal ablation of tissue 总被引:7,自引:0,他引:7
Induction heating of small, cylindrical ferromagnetic implants (1.4 cm long and 1 mm in diameter) is a method for treating deep-seated tumors. These implants, or ThermoRods trade mark, are placed within a lesion in 1-cm(2) arrays and are exposed to an alternating magnetic field. The implants absorb energy from that field and transfer it as heat to the surrounding tissue. Each ThermoRod trade mark offers approximately 400 mW of power, and to kill cells, the target temperature must be greater than 42 degrees C. In this work, a magnetic field-focusing device is employed to concentrate the induced magnetic flux toward a local region near the base of the prostate to increase the power output of proximal ThermoRods trade mark. This, in turn, allows for more complete thermal ablation of lesions near the base of the prostate where the heat-sink characteristics of the bladder can cause significant power losses. Boundary element analysis and in vitro testing have shown that the use of a ferrofluid-based field-focusing device can lead to a significant increase in power output of approximately 25% and 13%, respectively, of proximal ThermoRods trade mark. These preliminary results indicate that the incorporation of such a ferrofluid-based focusing device into ThermoRod trade mark treatments is promising for the avoidance of significant power loss and for assuring complete thermal ablation of prostatic lesions. 相似文献
993.
In many organisms completion of the first meiotic cell division depends on the correct assembly and disassembly of the synaptonemal
complex (SC). This is a structure discovered a little over 50 years ago, which is formed by the close association of axes
of homologous sister chromatid pairs. Its structure varies between organisms, although it retains a common tripartite organization
in species as evolutionarily distant as budding yeast and humans. In mammals it is essential for crossover formation and completion
of meiosis. Components of the mammalian SC have been identified only in the last 15 years, and mouse genetic approaches have
started revealing the importance for this structure only in the past 5 years. Here we discuss the progress that has been made
in the field of the mammalian SC and what approaches could be considered for its further study. 相似文献
994.
Luca Antiga Marina Piccinelli Lorenzo Botti Bogdan Ene-Iordache Andrea Remuzzi David A. Steinman 《Medical & biological engineering & computing》2008,46(11):1097-1112
We present a modeling framework designed for patient-specific computational hemodynamics to be performed in the context of
large-scale studies. The framework takes advantage of the integration of image processing, geometric analysis and mesh generation
techniques, with an accent on full automation and high-level interaction. Image segmentation is performed using implicit deformable
models taking advantage of a novel approach for selective initialization of vascular branches, as well as of a strategy for
the segmentation of small vessels. A robust definition of centerlines provides objective geometric criteria for the automation
of surface editing and mesh generation. The framework is available as part of an open-source effort, the Vascular Modeling
Toolkit, a first step towards the sharing of tools and data which will be necessary for computational hemodynamics to play
a role in evidence-based medicine. 相似文献
995.
Embryo transfer (ET) is the last stage of extracorporal fertilization during which the embryo is placed in the uterine cavity with a medium-filled catheter 2–3 days after in vitro fertilization. While fertilization in the laboratory occurs at very high rates (>:90%), the overall success of the procedure (i.e., take home baby) is still very low (<25%) and assumed to be mainly due to implantation failure. A computational model was developed to simulate ET within the uterine cavity by a fluid-filled catheter inserted into a two-dimensional channel with oscillating walls. The results showed that the speed at which the embryos are injected from the catheter dominates the procedure and controls the velocity of their transport within the uterine cavity. ET at excessively high injection speeds may lead to ectopic pregnancies, while uterine peristalsis affects transverse dispersion only during injection at low injection speeds. The presence of the catheter within the uterus does not affect flow patterns downstream of its tip. The potential risks to implantation failure due to mechanical factors involved in the ET processes are discussed. © 2003 Biomedical Engineering Society.
PAC2003: 8719-j, 8710+e 相似文献
996.
Materials are distributed throughout the body of mammals by fractal networks of branching tubes. Based on the scaling laws of the fractal structure, the vascular tree is reduced to an equivalent one-dimensional, tube model. A dispersion–convection partial differential equation with constant coefficients describes the heterogeneous concentration profile of an intravascular tracer in the vascular tree. A simple model for the mammalian circulatory system is built in entirely physiological terms consisting of a ring shaped, one-dimensional tube which corresponds to the arterial, venular, and pulmonary trees, successively. The model incorporates the blood flow heterogeneity of the mammalian circulatory system. Model predictions are fitted to published concentration-time data of indocyanine green injected in humans and dogs. Close agreement was found with parameter values within the expected physiological range. © 2003 Biomedical Engineering Society.
PAC2003: 8710+e, 8719Hh, 8719Uv 相似文献
997.
Robson C. Gutierre Mizue I. Egami Marta M. Antoniazzi Carlos Jared 《Comparative clinical pathology》2008,17(4):221-228
The caecilians (Amphibia, Gymnophiona) constitute one of the least known groups of terrestrial vertebrates because most species
live underground in quite inaccessible environments. Siphonops annulatus is an exclusively fossorial species and is the most extensively distributed caecilian in South America. Little is known of
this order concerning circulating granulocytes, including their morphological and cytochemical structure and ultrastructure.
This paper is part of a project covering the study of granulocytes in representative species of the order Amphibia. Blood
extensions were carried out and submitted to Leishman, Toluidine Blue, Periodic acid Schiff, Sirius Red and hydrogen o-toluidine peroxide methods. Part of the samples was prepared for conventional transmission electron microscopy. Among granular
leukocytes, mature and immature neutrophils and eosinophils were identified, plus basophils. The most frequent granulocyte
encountered in S. annulatus peripheral blood is the neutrophil. This is a cell with a hyper-segmented nucleus and with a very clear cytoplasm when compared
to the eosinophil, which presents large cytoplasmic acidophilic granules. On the other hand, the basophils present basophilic
and metachromatic granules. Glycogen was detected in the cytoplasm of the neutrophils and eosinophils, while basic protein
rich in amino acids was observed in the eosinophil’s granules. Myeloperoxidase activity was detected in the cytoplasm of the
neutrophils and eosinophils. Neutrophils were ultrastructurally detected with three types of small granules: eosinophils with
large and small spherical granules and basophils with large spherical granules with lamellate structures. 相似文献
998.
In vitro cellular immune responses to recombinant antigens of Mycobacterium avium subsp. paratuberculosis 下载免费PDF全文
Shin SJ Chang CF Chang CD McDonough SP Thompson B Yoo HS Chang YF 《Infection and immunity》2005,73(8):5074-5085
Five recombinant antigens (Ags; 85A, 85B, 85C, superoxide dismutase [SOD], and 35-kDa protein) were purified from Mycobacterium avium subsp. paratuberculosis and evaluated for their ability to stimulate peripheral blood mononuclear cells (PMBCs) from fecal-culture-positive cows (low and medium shedders) and culture-negative healthy cows. Recombinant Ags 85A, 85B, and 85C induced significant lymphocyte proliferation as well as the production of gamma interferon (IFN-gamma), interleukin-2 (IL-2), IL-12, and tumor necrosis factor alpha (TNF-alpha), but not IL-4, from low and medium shedders. The 85 antigen complex did not stimulate PMBC proliferation from culture-negative healthy cows. The 35-kDa protein also induced significant lymphocyte proliferation as well as the production of IFN-gamma and IL-4 from low and medium shedders. CD4(+) T cells and CD25(+) (IL-2R) T cells were stimulated the most by 85A and 85B, while the 35-kDa protein primarily stimulated CD21(+) B cells involved in humoral immune responses. Interestingly, SOD was less immunostimulatory than other antigens but strongly induced gammadelta(+) T cells, which are thought to be important in the early stages of infection, such as pathogen entry. These data provide important insight into how improved vaccines against mycobacterial infections might be constructed. 相似文献
999.
David P. Bazett-Jones Ren Li Eden Fussner Rosa Nisman Hesam Dehghani 《Chromosome research》2008,16(3):397-412
Electron microscopy has been the ‘gold standard’ of spatial resolution for studying the structure of the cell nucleus. Electron
spectroscopic imaging (ESI) offers advantages over conventional transmission electron microscopy by eliminating the need for
heavy-atom contrast agents. ESI also provides mass-dependent and element-specific information at high resolution, permitting
the distinguishing of structures that are primarily composed of protein, DNA, or RNA. The technique can be applied to understand
the structural consequences of epigenetic modifications, such as modified histones, on chromatin fiber morphology. ESI can
also be applied to elucidate the multifunctional behavior of subnuclear ‘organelles’ such as the nucleolus and promyelocytic
leukemia nuclear bodies.
The authors dedicate this paper to the memory of Ying Ren (1961–2007). We all benefited from knowing her. Our research advanced
through the technical creativity she provided. 相似文献
1000.