183 research outputs found
HIV Therapy without HBV Co-management in Ethiopia Fosters Emergence of Unintended HBV Drug Resistance and Vaccine Evasive Variants
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Dynamic structure mediates halophilic adaptation of a DNA polymerase from the deep-sea brines of the Red Sea.
The deep-sea brines of the Red Sea are remote and unexplored environments characterized by high temperatures, anoxic water, and elevated concentrations of salt and heavy metals. This environment provides a rare system to study the interplay between halophilic and thermophilic adaptation in biologic macromolecules. The present article reports the first DNA polymerase with halophilic and thermophilic features. Biochemical and structural analysis by Raman and circular dichroism spectroscopy showed that the charge distribution on the protein's surface mediates the structural balance between stability for thermal adaptation and flexibility for counteracting the salt-induced rigid and nonfunctional hydrophobic packing. Salt bridge interactions via increased negative and positive charges contribute to structural stability. Salt tolerance, conversely, is mediated by a dynamic structure that becomes more fixed and functional with increasing salt concentration. We propose that repulsive forces among excess negative charges, in addition to a high percentage of negatively charged random coils, mediate this structural dynamism. This knowledge enabled us to engineer a halophilic version of Thermococcus kodakarensis DNA polymerase.-Takahashi, M., Takahashi, E., Joudeh, L. I., Marini, M., Das, G., Elshenawy, M. M., Akal, A., Sakashita, K., Alam, I., Tehseen, M., Sobhy, M. A., Stingl, U., Merzaban, J. S., Di Fabrizio, E., Hamdan, S. M. Dynamic structure mediates halophilic adaptation of a DNA polymerase from the deep-sea brines of the Red Sea
High-K volcanism in the Afyon region, western Turkey: from Si-oversaturated to Si-undersaturated volcanism
Volcanic rocks of the Afyon province (eastern
part of western Anatolia) make up a multistage potassic and ultrapotassic alkaline series dated from 14 to 12 Ma. The early-stage Si-oversaturated volcanic rocks around the Afyon city and further southward are trachyandesitic volcanic activity (14.23 ± 0.09 Ma). Late-stage Si-undersaturated volcanism in the southernmost part of the Afyon volcanic province took place in three episodes inferred from their stratigraphic relationships and ages. Melilite–
leucitites (11.50 ± 0.03 Ma), spotted rachyandesites, tephryphonolites and lamproites (11.91 ± 0.13 Ma) formed in the first episode; trachyandesites in the second episode and finally phonotephrites, phonolite, basaltic trachyandesites and nosean-bearing trachyandesites during the last episode.
The parameter Q [normative q-(ne + lc + kls + ol)] of western Anatolia volcanism clearly decreased southward with time becoming zero in the time interval 10–15 Ma.
The magmatism experienced a sudden change in the extent of Si saturation after 14 Ma, during late-stage volcanic activity of Afyon volcanic province at around 12 Ma, though there was some coexistence of Si-oversaturated and Si-undersaturated magmas during the whole life of Afyon volcanic province
Spatial diversity in passive time reversal communications
A time reversal mirror exploits spatial diversity to achieve spatial and temporal focusing, a useful property for communications in an environment with significant multipath. Taking advantage of spatial diversity involves using a number of receivers distributed in space. This paper presents the impact of spatial diversity in passive time reversal communications between a probe source (PS) and a vertical receive array using at-sea experimental data, while the PS is either fixed or moving at about 4 knots. The performance of two different approaches is compared in terms of output signal-to-noise ratio versus the number of receiver elements: (1) time reversal alone and (2) time reversal combined with adaptive channel equalization. The time-varying channel response due to source motion requires an adaptive channel equalizer such that approach (2) outperforms approach (1) by up to 13 dB as compared to 5 dB for a fixed source case. Experimental results around 3 kHz with a 1 kHz bandwidth illustrate that as few as two or three receivers (i.e., 2 or 4 in array aperture) can provide reasonable performance at ranges of 4.2 and 10 km in 118 in deep water. (c) 2006 Acoustical Society of America
Quantifying risks and interventions that have affected the burden of diarrhoea among children younger than 5 years: an analysis of the Global Burden of Disease Study 2017
Background Many countries have shown marked declines in diarrhoeal disease mortality among children younger
than 5 years. With this analysis, we provide updated results on diarrhoeal disease mortality among children younger
than 5 years from the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017) and use the
study’s comparative risk assessment to quantify trends and effects of risk factors, interventions, and broader
sociodemographic development on mortality changes in 195 countries and territories from 1990 to 2017.
Methods This analysis for GBD 2017 had three main components. Diarrhoea mortality was modelled using vital
registration data, demographic surveillance data, and verbal autopsy data in a predictive, Bayesian, ensemble
modelling tool; and the attribution of risk factors and interventions for diarrhoea were modelled in a counterfactual
framework that combines modelled population-level prevalence of the exposure to each risk or intervention with the
relative risk of diarrhoea given exposure to that factor. We assessed the relative and absolute change in diarrhoea
mortality rate between 1990 and 2017, and used the change in risk factor exposure and sociodemographic status to
explain differences in the trends of diarrhoea mortality among children younger than 5 years.
Findings Diarrhoea was responsible for an estimated 533 768 deaths (95% uncertainty interval 477 162–593145)
among children younger than 5 years globally in 2017, a rate of 78·4 deaths (70·1–87·1) per 100000 children.
The diarrhoea mortality rate ranged between countries by over 685 deaths per 100000 children. Diarrhoea mortality
per 100000 globally decreased by 69·6% (63·1–74·6) between 1990 and 2017. Among the risk factors considered in
this study, those responsible for the largest declines in the diarrhoea mortality rate were reduction in exposure to
unsafe sanitation (13·3% decrease, 11·2–15·5), childhood wasting (9·9% decrease, 9·6–10·2), and low use of oral
rehydration solution (6·9% decrease, 4·8–8·4).
Interpretation Diarrhoea mortality has declined substantially since 1990, although there are variations by country.
Improvements in sociodemographic indicators might explain some of these trends, but changes in exposure to risk
factors—particularly unsafe sanitation, childhood growth failure, and low use of oral rehydration solution—appear to
be related to the relative and absolute rates of decline in diarrhoea mortality. Although the most effective interventions
might vary by country or region, identifying and scaling up the interventions aimed at preventing and protecting
against diarrhoea that have already reduced diarrhoea mortality could further avert many thousands of deaths due to
this illness.SMA acknowledges the International Centre for Casemix and Clinical
Coding, Faculty of Medicine, National University of Malaysia and
Department of Health Policy and Management, Faculty of Public Health,
Kuwait University for their approval and support to participate in this
research project. AsA acknowledges funding support from the
Department of Science and Technology, Government of India through
the INSPIRE faculty scheme. AlaB acknowledges support from the
Public Health Agency of Canada. AleB acknowledges support for
research from the Project of Ministry of Education, Science
and Technology of the Republic of Serbia (number III45005).
FC acknowledges funding support from Foundation for Science and
Technology/Minister of Science, Technology, and Higher Education
through national funds (UID/MULTI/04378/2019 and UID/
QUI/50006/2019). AMS was supported by the Egyptian Fulbright
Mission Program. MMSM acknowledges the support from the Ministry
of Education, Science and Technological Development, Republic of
Serbia (Contract No. 175087). AS acknowledges support from Health
Data Research UK
Effectiveness of nano-calcium phosphate paste on sensitivity during and after bleaching: a randomized clinical trial
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