bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Antituberculosis Drug Ethambutol Selectively Blocks Apical Growth in CMN Group Bacteria
Authors: Schubert Karin , Sieger Boris , Meyer Fabian , Giacomelli Giacomo , Böhm Kati , Rieblinger Angela , Lindenthal Laura , Sachs Nadja , Wanner Gerhard , Bramkamp Marc 
Published: February 2017

ABSTRACT

Members of the genus
Mycobacterium
are the most prevalent cause of infectious diseases. Mycobacteria have a complex cell envelope containing a peptidoglycan layer and an additional arabinogalactan polymer to which a mycolic acid bilayer is linked; this complex, multilayered cell wall composition (mAGP) is conserved among all CMN group bacteria. The arabinogalactan and mycolic acid synthesis pathways constitute effective drug targets for tuberculosis treatment. Ethambutol (EMB), a classical antituberculosis drug, inhibits the synthesis of the arabinose polymer. Although EMB acts bacteriostatically, its underlying molecular mechanism remains unclear. Here, we used
Corynebacterium glutamicum
and
Mycobacterium phlei
as model organisms to study the effects of EMB at the single-cell level. Our results demonstrate that EMB specifically blocks apical cell wall synthesis, but not cell division, explaining the bacteriostatic effect of EMB. Furthermore, the data suggest that members of the family
Corynebacterineae
have two dedicated machineries for cell elongation (elongasome) and cytokinesis (divisome).

IMPORTANCE
Antibiotic treatment of bacterial pathogens has contributed enormously to the increase in human health. Despite the apparent importance of antibiotic treatment of bacterial infections, surprisingly little is known about the molecular functions of antibiotic actions in the bacterial cell. Here, we analyzed the molecular effects of ethambutol, a first-line antibiotic against infections caused by members of the genus
Mycobacterium
. We find that this drug selectively blocks apical cell growth but still allows for effective cytokinesis. As a consequence, cells survive ethambutol treatment and adopt a pneumococcal cell growth mode with cell wall synthesis only at the site of cell division. However, combined treatment of ethambutol and beta-lactam antibiotics acts synergistically and effectively stops cell proliferation.
Isotopic signature of dissolved iron delivered to the Southern Ocean from hydrothermal vents in the East Scotia Sea
Authors: Klar Jessica K. , James Rachael H. , Gibbs Dakota , Lough Alastair , Parkinson Ian , Milton J. Andrew , Hawkes Jeffrey A. , Connelly Douglas P. 
Published: February 2017

Abstract
It has recently been demonstrated that hydrothermal vents are an important source of dissolved Fe (dFe) to the Southern Ocean. The isotopic composition (δ56Fe) of dFe in vent fluids appears to be distinct from other sources of dFe to the deep ocean, but the evolution of δ56Fe during mixing between vent fluids and seawater is poorly constrained. Here we present the evolution of δ56Fe for dFe in hydrothermal fluids and dispersing plumes from two sites in the East Scotia Sea. We show that δ56Fe values in the buoyant plume are distinctly lower (as low as −1.19‰) than the hydrothermal fluids (−0.29‰), attributed to (1) precipitation of Fe sulfides in the early stages of mixing, and (2) partial oxidation of Fe(II) to Fe(III), &gt;55% of which subsequently precipitates as Fe oxyhydroxides. By contrast, the δ56Fe signature of stabilized dFe in the neutrally buoyant plume is −0.3‰ to −0.5‰. This cannot be explained by continued dilution of the buoyant plume with background seawater; rather, we suggest that isotope fractionation of dFe occurs during plume dilution due to Fe ligand complexation and exchange with labile particulate Fe. The δ56Fe signature of stabilized hydrothermal dFe in the East Scotia Sea is distinct from background seawater and may be used to quantify the hydrothermal dFe input to the ocean interior.
Stratigraphic unmixing reveals repeated hypoxia events over the past 500 yr in the northern Adriatic Sea
Authors: Tomašových Adam , Gallmetzer Ivo , Haselmair Alexandra , Kaufman Darrell S. , Vidović Jelena , Zuschin Martin 
Published: February 2017

Abstract
In the northern Adriatic Sea and in most semienclosed coastal regions worldwide, hypoxia induced by eutrophication in the late 20th century caused major die-offs of coastal marine organisms. However, ecosystem responses to hypoxia over longer centennial scales are unclear because the duration of direct observations is limited to a few decades and/or the temporal resolution of sedimentary archives is compromised by slow sedimentation and bioturbation. To assess whether perturbations of ecosystems by hypoxia recurred over centuries in the northern Adriatic Sea, we evaluate the timing and forcing of past hypoxia events based on the production history of the opportunistic, hypoxia-tolerant bivalve Corbula gibba, using 210Pb data, radiocarbon dating, amino acid racemization, and distribution of foraminifers in sediment cores that capture the past 500 yr in the Gulf of Trieste. Unmixing the stratigraphic record on the basis of 311 shells of C. gibba, we show that the reconstructed fluctuations in abundance do not correlate with abundances in the raw stratigraphic record. We find that production of C. gibba has undergone major decadal-scale fluctuations since the 18th century, with outbreaks corresponding to density of more than 1000 individuals per square meter. These outbreaks represent long-term phenomena in the northern Adriatic ecosystem rather than novel states characteristic of the 20th century eutrophication. They positively correlate with centennial-scale fluctuations in sea-surface temperature, indicating that the hypoxia events were coupled with water-column stratification rather than with nutrient enrichment.
Do biomass fuel use and consumption of unsafe water mediate educational inequalities in stillbirth risk? An analysis of the 2007 Ghana Maternal Health Survey
Authors: Amegah A Kofi , Näyhä Simo , Jaakkola Jouni J K 
Published: February 2017

BackgroundNumerous studies have explored the association between educational inequalities and stillbirth but most have failed to elaborate how low educational attainment leads to an increased risk of stillbirth. We hypothesised that use of biomass fuels and consumption of unsafe water related to low educational attainment could explain the stillbirth burden in Ghana attributable to socioeconomic disadvantage.MethodsData from the 2007 Ghana Maternal Health Survey, a nationally representative population-based survey were analysed for this study. Of the10 370 women aged 15–49 years interviewed via structured questionnaires for the survey, 7183 primiparous and multiparous women qualified for inclusion in the present study.ResultsIn a logistic regression analysis that adjusted for age, area of residence, marital status and ethnicity of women, lower maternal primary education was associated with a 62% (OR=1.62; 95% CI 1.04 to 2.52) increased lifetime risk of stillbirth. Biomass fuel use and consumption of unsafe water mediated 18% and 8% of the observed effects, respectively. Jointly these two exposures explained 24% of the observed effects. The generalised additive modelling revealed a very flat inverted spoon-shaped smoothed curve which peaked at low levels of schooling (2–3 years) and confirms the findings from the logistic regression analysis.ConclusionsOur results show that biomass fuel use and unsafe water consumption could be important pathways through which low maternal educational attainment leads to stillbirths in Ghana and similar developing countries. Addressing educational inequalities in developing countries is thus essential for ensuring household choices that curtail environmental exposures and help improve pregnancy outcomes.
Transformer Less Voltage Quadrupler Based DC-DC Converter with Coupled Inductor and PI Filter for Increased Voltage Gain and Efficiency
Authors: Sujitha C. , Ravi S. , Diarra Bakary , Chuma Joseph 
Published: February 2017

<p>In this paper a voltage quadrupler dc-dc converter with coupled inductor and π filter is presented. The use of the coupled inductor reduces the high leakage inductance which is present in a transformer enabled converter. The output ripples in the converter is reduced by providing a π filter. The interleaved voltage quadrupler is used in this system in order to boost the output voltage. The voltage multiplier improves the output voltage gain. The main advantage of this system is more voltage gain when compared with the transformer eneabled circuit and the overall efficiency of the system is improved. The circuit is simple to control. As a final point of this research, the simulation and the hardware investigational results are presented to demonstrate the effectiveness of this proposed converter.</p>
Comparative Performance Study for Closed Loop Operation of an Adjustable Speed Permanent Magnet Synchronous Motor Drive with Different Controllers
Authors: Sain Chiranjit , Banerjee Atanu , Biswas Pabitra Kumar 
Published: February 2017

In this paper an extensive comparative study is carried out between PI and PID controlled closed loop model of an adjustable speed Permanent Magnet Synchronous Motor (PMSM) drive. The incorporation of Sinusoidal Pulse Width Modulation (SPWM) strategy establishes near sinusoidal armature phase currents and comparatively less torque ripples without sacrificing torque/weight ratio. In this closed loop model of PMSM drive, the information about reference speed is provided to a speed controller, to ensure that actual drive speed tracks the reference speed with ideally zero steady state speed error. The entire model of PMSM closed loop drive is divided into two loops, inner loop current and outer loop speed. By taking the different combinations of two classical controllers (PI &amp; PID) related with two loop control structure, different approximations are carried out. Hence a typical comparative study is introduced to familiar with the different performance indices of the system corresponding to time domain and frequency domain specifications. Therefore overall performance of closed loop PMSM drive is tested and effectiveness of controllers will be determined for different combinations.
Electric Power Converter with a Wide Input Voltage Range
Authors: Khokhlov K.O. , Khokhlov G.K. , Ishchenko A.V. , Cherepanov A.N. , Naronov A.S. 
Published: February 2017

The electric power converter for downhole telemetry systems of oil-well pumps include a downhole block connected to the pump that contains electronic circuits required for the operation of the motor pump sensors and transmission of data about their condition to the surface are described. A few methods of electric power conversion for this purpose are considered. The circuit contained two steps of voltage converting are proposed. The electrical scheme of this method is considered in the article. Proposed decisions are simulated and verified experimentally. The input high supply voltage range (200-4200 V) without loss of efficiency (even temporary) was obtained. The results of simulation and experimental studies have shown very close results.
Photovoltaic System with SEPIC Converter Controlled by the Fuzzy Logic
Authors: Oudda Meryem , Hazzab Abdeldjebar 
Published: February 2017

<span lang="EN-US">In this work, a fuzzy logic controller is used to control the output voltage of a photovoltaic system with a DC-DC converter; type Single Ended Primary Inductor Converter (SEPIC). The system is designed for 210 W solar PV (SCHOTT 210) panel and to feed an average demand of 78 W. This system includes solar panels, SEPIC converter and fuzzy logic controller. The SEPIC converter provides a constant DC bus voltage and its duty cycle controlled by the fuzzy logic controller which is needed to improve PV panel’s utilization efficiency. A fuzzy logic controller (FLC) is also used to generate the PWM signal for the SEPIC converter. </span>
Comparative Study of Various Adjustable Speed Drives During Voltage Sag
Authors: S Renukadevi , M Rathinakumar 
Published: February 2017

<p>This Paper compares the sensitivity of various adjustable speed drives to voltage sag for the process control applications. Three phase voltage sag of type B caused due to SLG fault is considered and four topologies of ASD’s are compared in this paper. The comparison is done especially in speed, voltage, current and torque of the ASDs. Diode rectifier without z source inverter, diode rectifier with z source inverter , single phase two leg Vienna rectifier and single phase neutral linked Vienna with z source inverter are compared and the best one is highlighted. The circuits of various ASD’s are simulated using Matlab /Simulink. </p>
Augmentation of Muscle Blood Flow by Ultrasound Cavitation Is Mediated by ATP and Purinergic Signaling
Authors: Belcik J. Todd , Davidson Brian P. , Xie Aris , Wu Melinda D. , Yadava Mrinal , Qi Yue , Liang Sherry , Chon Chae Ryung , Ammi Azzdine Y. , Field Joshua , Harmann Leanne , Chilian William M. , Linden Joel , Lindner Jonathan R. 
Published: February 2017

Background:
Augmentation of tissue blood flow by therapeutic ultrasound is thought to rely on convective shear. Microbubble contrast agents that undergo ultrasound-mediated cavitation markedly amplify these effects. We hypothesized that purinergic signaling is responsible for shear-dependent increases in muscle perfusion during therapeutic cavitation.

Methods:

Unilateral exposure of the proximal hindlimb of mice (with or without ischemia produced by iliac ligation) to therapeutic ultrasound (1.3 MHz, mechanical index 1.3) was performed for 10 minutes after intravenous injection of 2×10
8
lipid microbubbles. Microvascular perfusion was evaluated by low-power contrast ultrasound perfusion imaging. In vivo muscle ATP release and in vitro ATP release from endothelial cells or erythrocytes were assessed by a luciferin-luciferase assay. Purinergic signaling pathways were assessed by studying interventions that (1) accelerated ATP degradation; (2) inhibited P2Y receptors, adenosine receptors, or K
ATP
channels; or (3) inhibited downstream signaling pathways involving endothelial nitric oxide synthase or prostanoid production (indomethacin). Augmentation in muscle perfusion by ultrasound cavitation was assessed in a proof-of-concept clinical trial in 12 subjects with stable sickle cell disease.

Results:
Therapeutic ultrasound cavitation increased muscle perfusion by 7-fold in normal mice, reversed tissue ischemia for up to 24 hours in the murine model of peripheral artery disease, and doubled muscle perfusion in patients with sickle cell disease. Augmentation in flow extended well beyond the region of ultrasound exposure. Ultrasound cavitation produced an ≈40-fold focal and sustained increase in ATP, the source of which included both endothelial cells and erythrocytes. Inhibitory studies indicated that ATP was a critical mediator of flow augmentation that acts primarily through either P2Y receptors or adenosine produced by ectonucleotidase activity. Combined indomethacin and inhibition of endothelial nitric oxide synthase abolished the effects of therapeutic ultrasound, indicating downstream signaling through both nitric oxide and prostaglandins.

Conclusions:
Therapeutic ultrasound using microbubble cavitation to increase muscle perfusion relies on shear-dependent increases in ATP, which can act through a diverse portfolio of purinergic signaling pathways. These events can reverse hindlimb ischemia in mice for >24 hours and increase muscle blood flow in patients with sickle cell disease.

Clinical Trial Registration:

URL:
http://clinicaltrials.gov
. Unique identifier: NCT01566890.
Cardiac Overexpression of S100A6 Attenuates Cardiomyocyte Apoptosis and Reduces Infarct Size After Myocardial Ischemia‐Reperfusion
Authors: Mofid Azadeh , Newman Nadav S. , Lee Paul J. H. , Abbasi Cynthia , Matkar Pratiek N. , Rudenko Dmitriy , Kuliszewski Michael A. , Chen Hao H. , Afrasiabi Kolsoom , Tsoporis James N. , Gramolini Anthony O. , Connelly Kim A. , Parker Thomas G. , Leong‐Poi Howard 
Published: February 2017

Background

Cardiomyocyte‐specific transgenic mice overexpressing S100A6, a member of the family of
EF
‐hand calcium‐binding proteins, develop less cardiac hypertrophy, interstitial fibrosis, and myocyte apoptosis after permanent coronary ligation, findings that support S100A6 as a potential therapeutic target after acute myocardial infarction. Our purpose was to investigate S100A6 gene therapy for acute myocardial ischemia‐reperfusion.

Methods and Results
We first performed in vitro studies to examine the effects of S100A6 overexpression and knockdown in rat neonatal cardiomyocytes. S100A6 overexpression improved calcium transients and protected against apoptosis induced by hypoxia‐reoxygenation via enhanced calcineurin activity, whereas knockdown of S100A6 had detrimental effects. For in vivo studies, human S100A6 plasmid or empty plasmid was delivered to the left ventricular myocardium by ultrasound‐targeted microbubble destruction in Fischer‐344 rats 2 days prior to a 30‐minute ligation of the left anterior descending coronary artery followed by reperfusion. Control animals received no therapy. Pretreatment with S100A6 gene therapy yielded a survival advantage compared to empty‐plasmid and nontreated controls. S100A6‐pretreated animals had reduced infarct size and improved left ventricular systolic function, with less myocyte apoptosis, attenuated cardiac hypertrophy, and less cardiac fibrosis.

Conclusions
S100A6 overexpression by ultrasound‐targeted microbubble destruction helps ameliorate myocardial ischemia‐reperfusion, resulting in lower mortality and improved left ventricular systolic function post–ischemia‐reperfusion via attenuation of apoptosis, reduction in cardiac hypertrophy, and reduced infarct size. Our results indicate that S100A6 is a potential therapeutic target for acute myocardial infarction.
Altered Blood Flow Response to Small Muscle Mass Exercise in Cancer Survivors Treated With Adjuvant Therapy
Authors: Didier Kaylin D. , Ederer Austin K. , Reiter Landon K. , Brown Michael , Hardy Rachel , Caldwell Jacob , Black Christopher , Bemben Michael G. , Ade Carl J. 
Published: February 2017

Background
Adjuvant cancer treatments have been shown to decrease cardiac function. In addition to changes in cardiovascular risk, there are several additional functional consequences including decreases in exercise capacity and increased incidence of cancer‐related fatigue. However, the effects of adjuvant cancer treatment on peripheral vascular function during exercise in cancer survivors have not been well documented. We investigated the vascular responses to exercise in cancer survivors previously treated with adjuvant cancer therapies.

Methods and Results

Peripheral vascular responses were investigated in 11 cancer survivors previously treated with adjuvant cancer therapies (age 58±6 years, 34±30 months from diagnosis) and 9 healthy controls group matched for age, sex, and maximal voluntary contraction. A dynamic handgrip exercise test at 20% maximal voluntary contraction was performed with simultaneous measurements of forearm blood flow and mean arterial pressure. Forearm vascular conductance was calculated from forearm blood flow and mean arterial pressure. Left ventricular ejection time index (
LVET
i) was derived from the arterial pressure wave form. Forearm blood flow was attenuated in cancer therapies compared to control at 20% maximal voluntary contraction (189.8±53.8 vs 247.9±80.3 mL·min
−1
, respectively). Forearm vascular conductance was not different between groups at rest or during exercise. Mean arterial pressure response to exercise was attenuated in cancer therapies compared to controls (107.8±10.8 vs 119.2±16.2 mm Hg).
LEVT
i was lower in cancer therapies compared to controls.

Conclusions
These data suggest an attenuated exercise blood flow response in cancer survivors ≈34 months following adjuvant cancer therapy that may be attributed to an attenuated increase in mean arterial pressure.
Stroke With Unknown Time of Symptom Onset
Authors: Thomalla Götz , Boutitie Florent , Fiebach Jochen B. , Simonsen Claus Z. , Nighoghossian Norbert , Pedraza Salvador , Lemmens Robin , Roy Pascal , Muir Keith W. , Ebinger Martin , Ford Ian , Cheng Bastian , Galinovic Ivana , Cho Tae-Hee , Puig Josep , Thijs Vincent , Endres Matthias , Fiehler Jens , Gerloff Christian 
Published: February 2017

Background and Purpose—
We describe clinical and magnetic resonance imaging (MRI) characteristics of stroke patients with unknown time of symptom onset potentially eligible for thrombolysis from a large prospective cohort.

Methods—
We analyzed baseline data from WAKE-UP (Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke: A Randomized, Doubleblind, Placebo-Controlled Trial), an investigator-initiated, randomized, placebo-controlled trial of MRI-based thrombolysis in stroke patients with unknown time of symptom onset. MRI judgment included assessment of the mismatch between visibility of the acute ischemic lesion on diffusion-weighted imaging and fluid-attenuated inversion recovery.

Results—

Of 1005 patients included, diffusion-weighted imaging and fluid-attenuated inversion recovery mismatch was present in 479 patients (48.0%). Patients with daytime-unwitnessed stroke (n=138, 13.7%) had a shorter delay between symptom recognition and hospital arrival (1.5 versus 1.8 hours;
P
=0.002), a higher National Institutes of Stroke Scale score on admission (8 versus 6;
P
<0.001), and more often aphasia (72.5% versus 34.0%;
P
<0.001) when compared with stroke patients waking up from nighttime sleep. Frequency of diffusion-weighted imaging and fluid-attenuated inversion recovery mismatch was comparable between both groups (43.7% versus 48.7%;
P
=0.30).

Conclusions—
Almost half of the patients with unknown time of symptom onset stroke otherwise eligible for thrombolysis had MRI findings making them likely to be within a time window for safe and effective thrombolysis. Patients with daytime onset unwitnessed stroke differ from wake-up stroke patients with regards to clinical characteristics but are comparable in terms of MRI characteristics of lesion age.

Clinical Trial Registration—

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT01525290. URL:
https://www.clinicaltrialsregister.eu
. Unique identifier: 2011-005906-32.