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111.
Moracci M Cobucci Ponzano B Trincone A Fusco S De Rosa M van Der Oost J Sensen CW Charlebois RL Rossi M 《The Journal of biological chemistry》2000,275(29):22082-22089
We here report the first molecular characterization of an alpha-xylosidase (XylS) from an Archaeon. Sulfolobus solfataricus is able to grow at temperatures higher than 80 degrees C on several carbohydrates at acidic pH. The isolated xylS gene encodes a monomeric enzyme homologous to alpha-glucosidases, alpha-xylosidases, glucoamylases and sucrase-isomaltases of the glycosyl hydrolase family 31. xylS belongs to a cluster of four genes in the S. solfataricus genome, including a beta-glycosidase, an hypothetical membrane protein homologous to the major facilitator superfamily of transporters, and an open reading frame of unknown function. The alpha-xylosidase was overexpressed in Escherichia coli showing optimal activity at 90 degrees C and a half-life at this temperature of 38 h. The purified enzyme follows a retaining mechanism of substrate hydrolysis, showing high hydrolytic activity on the disaccharide isoprimeverose and catalyzing the release of xylose from xyloglucan oligosaccharides. Synergy is observed in the concerted in vitro hydrolysis of xyloglucan oligosaccharides by the alpha-xylosidase and the beta-glycosidase from S. solfataricus. The analysis of the total S. solfataricus RNA revealed that all the genes of the cluster are actively transcribed and that xylS and orf3 genes are cotranscribed. 相似文献
112.
Abstract The Open Bay Island skink (Oligosoma taumakae) is one of New Zealand's rarest lizard species. Until 2010, it was known only from two small islands in the Open Bay Island Group, a Māori-owned wildlife sanctuary in South Westland, New Zealand. Skinks on these islands are threatened by predation from weka (Gallirallus australis), a flightless native rail thought to have been introduced to the Open Bay Islands c. 100 years ago. Here, we describe the discovery of Open Bay Island skinks on two vegetated rock stacks located off the coast of Barn Bay, 52 km southwest of the Open Bay Islands. Although small (c. 0.10 and 0.36 ha), the Barn Islands appear to be predator-free, providing an important sanctuary for the skinks. We recommend: (1) a survey of mainland sites with suitable habitat; and (2) an evaluation of the need for island biosecurity measures for detecting and responding to incursions of small mammals. 相似文献
113.
Gabriel Chamie Dalsone Kwarisiima Tamara D. Clark Jane Kabami Vivek Jain Elvin Geng Laura B. Balzer Maya L. Petersen Harsha Thirumurthy Edwin D. Charlebois Moses R. Kamya Diane V. Havlir 《PloS one》2014,9(1)
Background
The high burden of undiagnosed HIV in sub-Saharan Africa is a major obstacle for HIV prevention and treatment. Multi-disease, community health campaigns (CHCs) offering HIV testing are a successful approach to rapidly increase HIV testing rates and identify undiagnosed HIV. However, a greater understanding of population-level uptake is needed to maximize effectiveness of this approach.Methods
After community sensitization and a census, a five-day campaign was performed in May 2012 in a rural Ugandan community. The census enumerated all residents, capturing demographics, household location, and fingerprint biometrics. The CHC included point-of-care screening for HIV, malaria, TB, hypertension and diabetes. Residents who attended vs. did not attend the CHC were compared to determine predictors of participation.Results
Over 12 days, 18 census workers enumerated 6,343 residents. 501 additional residents were identified at the campaign, for a total community population of 6,844. 4,323 (63%) residents and 556 non-residents attended the campaign. HIV tests were performed in 4,795/4,879 (98.3%) participants; 1,836 (38%) reported no prior HIV testing. Of 2674 adults tested, 257 (10%) were HIV-infected; 125/257 (49%) reported newly diagnosed HIV. In unadjusted analyses, adult resident campaign non-participation was associated with male sex (62% male vs. 67% female participation, p = 0.003), younger median age (27 years in non-participants vs. 32 in participants; p<0.001), and marital status (48% single vs. 71% married/widowed/divorced participation; p<0.001). In multivariate analysis, single adults were significantly less likely to attend the campaign than non-single adults (relative risk [RR]: 0.63 [95% CI: 0.53–0.74]; p<0.001), and adults at home vs. not home during census activities were significantly more likely to attend the campaign (RR: 1.20 [95% CI: 1.13–1.28]; p<0.001).Conclusions
CHCs provide a rapid approach to testing a majority of residents for HIV in rural African settings. However, complementary strategies are still needed to engage young, single adults and achieve universal testing. 相似文献114.
Carina Marquez J. Lucian Davis Achilles Katamba Priscilla Haguma Emmanuel Ochom Irene Ayakaka Gabriel Chamie Grant Dorsey Moses R. Kamya Edwin Charlebois Diane V. Havlir Adithya Cattamanchi 《PloS one》2014,9(8)
Background
Improving childhood tuberculosis (TB) evaluation and care is a global priority, but data on performance at community health centers in TB endemic regions are sparse.Objective
To describe the current practices and quality of TB evaluation for children with cough ≥2 weeks'' duration presenting to community health centers in Uganda.Methods
Cross-sectional analysis of children (<15 years) receiving care at five Level IV community health centers in rural Uganda for any reason between 2009–2012. Quality of TB care was assessed using indicators derived from the International Standards of Tuberculosis Care (ISTC).Results
From 2009–2012, 1713 of 187,601 (0.9%, 95% CI: 0.4–1.4%) children presenting to community health centers had cough ≥ 2 weeks'' duration. Of those children, only 299 (17.5%, 95% CI: 15.7–19.3%) were referred for sputum microscopy, but 251 (84%, 95% CI: 79.8–88.1%) completed sputum examination if referred. The yield of sputum microscopy was only 3.6% (95% CI: 1.3–5.9%), and only 55.6% (95% CI: 21.2–86.3%) of children with acid-fast bacilli positive sputum were started on treatment. Children under age 5 were less likely to be referred for sputum examination and to receive care in accordance with ISTC. The proportion of children evaluated in accordance with ISTC increased over time (4.6% in 2009 to 27.9% in 2012, p = 0.03), though this did not result in increased case-detection.Conclusion
The quality of TB evaluation was poor for children with cough ≥2 weeks'' duration presenting for health care. Referrals for sputum smear microscopy and linkage to TB treatment were key gaps in the TB evaluation process, especially for children under the age of five. 相似文献115.
Mathieu Charlebois Milan Jirásek Philippe K. Zysset 《Biomechanics and modeling in mechanobiology》2010,9(5):597-611
Using the three-dimensional morphological data provided by computed tomography, finite element (FE) models can be generated
and used to compute the stiffness and strength of whole bones. Three-dimensional constitutive laws capturing the main features
of bone mechanical behavior can be developed and implemented into FE software to enable simulations on complex bone structures.
For this purpose, a constitutive law is proposed, which captures the compressive behavior of trabecular bone as a porous material
with accumulation of irreversible strain and loss of stiffness beyond its yield point and softening beyond its ultimate point.
To account for these features, a constitutive law based on damage coupled with hardening anisotropic elastoplasticity is formulated
using density and fabric-based tensors. To prevent mesh dependence of the solution, a nonlocal averaging technique is adopted.
The law has been implemented into a FE software and some simple simulations are first presented to illustrate its behavior.
Finally, examples dealing with compression of vertebral bodies clearly show the impact of softening on the localization of
the inelastic process. 相似文献
116.
117.
Several fundamental questions remain enigmatic concerning human olfactory
sensitivity, including (i) whether detection threshold differences exist
between the two sides of the nose (and, if so, whether such differences are
influenced by handedness) and (ii) whether bilateral (i.e. binasal)
stimulation leads to lower thresholds than unilateral stimulation (and, if
so, whether the degree of facilitation is inversely related to general
olfactory ability). In this study, and well-validated single staircase
procedure was used to establish bilateral and unilateral detection
thresholds for the cranial nerve I stimulant phenyl ethyl alcohol in 130
right- and 33 left-handed subjects. No differences in sensitivity between
the left and right sides of the nose were observed in either group.
Bilateral thresholds were lower, on average, than unilateral thresholds
when the latter were categorized in terms of left and right nares. However,
the bilateral thresholds did not differ significantly from those of the
side of the nose with the lower threshold. Overall smell ability, as
measured by the University of Pennsylvania Smell Identification Test, did
not interact with any of the test measures. These data imply that (i) the
left and right sides of the nose do not systematically differ in detection
threshold sensitivity for either dextrals or sinistrals and (ii) if central
integration of left:right olfactory threshold sensitivity occurs, its
effects do not exceed the function of the better side of the nose.
相似文献
118.
119.
Organizational characteristics and information content of an archaeal genome: 156kb of sequence from Sulfolobus solfataricus P2 总被引:5,自引:1,他引:4
120.
Mathieu Charlebois Hamid Motallebzadeh W. Robert J. Funnell 《Biomechanics and modeling in mechanobiology》2013,12(4):705-715
Some biological tissues are repeatedly stimulated under cyclic loading, and this stimulation can be combined with large pressures, thus leading to large deformations. For such applications, visco-hyperelastic models have been proposed in the literature and used in finite-element studies. An extensively used quasi-linear model (QLVH), which assumes linear evolution equations, is compared with a nonlinear model (NLVH), which assumes a multiplicative split of the deformation gradient. The comparison is made here using sets of simulations covering a large frequency range. Lost and stored energies are computed, and the additional parameter of the NLVH model is set to two values found in the literature (NLVH-2 and NLVH-30 models). The predicted behaviour is very similar for all models at small strains, with each time constant (and corresponding viscous modulus) being associated with a damping peak and a stored-energy increase. When the strain amplitude is increased, the ratio of lost to stored energy increases for the QLVH model, but decreases for the NLVH models. The NLVH-30 model also displays a shift of the peak damping towards higher frequencies. Before reaching a steady state, all models display a decay of energy independent of the frequency, and the additional parameter of the NLVH model permits the modelling of complex types of evolution of the damping. In conclusion, this study compares the behaviour of two viscous hyper-elastic laws to allow an informed choice between them. 相似文献