bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biosynthesized Iron Sulfide Nanocluster Enhanced Anodic Current Generation by Sulfate Reducing Bacteria in Microbial Fuel Cells
Authors: Murugan Muralidharan , Miran Waheed , Masuda Takuya , Lee Dae S. , Okamoto Akihiro 
Published: September 2018

AbstractThe anodic oxidation of sulfide metabolically generated from sulfate is considered to be the primary mechanism of sulfate reducing bacteria (SRB) to contribute to the current generation in Microbial Fuel Cells (MFCs). However, the other redox active metabolic by‐product of conductive iron sulfide (FeS) has been seldomly studied in the context of anodic current generation. Here, we demonstrate that the biomineralized FeS increased the anodic current production in Desulfovibrio vulgaris Hildenborough, compared with that mediated by diffusive sulfate. Chronoamperometry on indium tin‐doped oxide electrodes (ITO) poised at +0.4 V (vs SHE) in the presence of lactate and sulfate showed that the presence of ferrous ion caused twice more anodic current than that in the absence of the iron. Linear Sweep Voltammetry (LSV), Scanning Electron Microscopy (SEM) and X‐ray Photoelectron Spectroscopy confirmed that the aggregation formation of cells with FeS and FeS2 particles on the surface of the ITO electrode. These iron sulfur precipitates were more oxidized on the anode surfaces once lactate was depleted as electron source. The presented data suggests that biosynthesized FeS mediates the electron transport from D. vulgaris Hildenborough to the electrode surface. Given microbial capability of FeS biosynthesis is general among SRB, the FeS‐mediated mechanism may dominate anodic current generation of SRB in MFCs.
Beyond Common Metal–Metal Bonds, κ3‐Bis(donor)ferrocenyl→Transition‐Metal Interactions
Authors: Ringenberg Mark R. 
Published: September 2018

AbstractLigands with 1,1′‐bis(donor)ferrocene motif are capable of a wide range of binding modes, including the trans chelation mode in which there is a Fe−M interaction (κ3‐D,Fe,D), in the form of a dative Fe→TM bond (TM=transition metal). This Minireview will explore the nature of this Fe–TM interaction thorough select examples as well as how to characterize a Fe→TM dative bond using physical, computational, and spectroscopic techniques.
The enzymatic resolution of 1‐(4‐chlorophenyl)ethylamine by Novozym 435 to prepare a novel triazolopyrimidine herbicide
Authors: Zhang Yinjun , Cheng Feifei , Yan Hongde , Zheng Jianyong , Wang Zhao 
Published: September 2018

AbstractThe kinetic resolution of (R,S)‐1‐(4‐chlorophenyl)ethylamine was accomplished using a commercial lipase from Candida antarctica (Novozym 435). The performance of this lipase was investigated for the enantioselective amidation of (R,S)‐1‐(4‐chlorophenyl)ethylamine, leaving the target product (S)‐1‐(4‐chlorophenyl)ethylamine in its unreacted form. The effects of various types of solvents and an acyl donor, the molar ratio of the substrate to the acyl donor, and the reaction temperature were studied. The optimum reaction conditions were found to result in amidation with methyl 2‐tetrahydrofuroate at 40°C in methyl tert‐butyl ether, with a substrate/acyl donor molar ratio of 1:2.4. The conversion rate of (R,S)‐1‐(4‐chlorophenyl)ethylamine was 52%, with an enantiomeric excess of 99% towards the unreacted substrate in a reaction time of 22 hours. Finally, using optically pure (S)‐1‐(4‐chlorophenyl)ethylamine as the raw material, the chemical synthesis of (S)‐N‐(1‐(4‐chlorphenyl)ethyl)‐2‐(5,7‐dimethyl‐[1,2,4]triazolo[1,5‐a]pyrimidin‐2‐ylthio)acetamide, a novel triazolopyrimidine herbicide, was achieved, and the total yield and purity were 83.5% and 95.3%, respectively.
Enantioseparation of chiral mandelic acid derivatives by supercritical fluid chromatography
Authors: Ding Jiawei , Zhang Ming , Dai Huixue , Lin Chunmian 
Published: September 2018

AbstractMandelic acid and its derivatives are important chiral analogs which are widely used in the pharmaceutical synthetic industry. The present study investigated the enantiomeric separation of six mandelic acids (mandelic acid, 2‐chloromandelic acid, 3‐chloromandelic acid, 4‐chloromandelic acid, 4‐bromomandelic acid, 4‐methoxymandelic acid) on the Chiralpak AD‐3 column by supercritical fluid chromatography. The influences of volume fraction of trifluoroacetic acid, type and percentage of modifier, column temperature, and backpressure on the separation efficiency were investigated. And the enantiomer elution order was determined. The results show that, for a given modifier, the retention factor, the separation factor, and the separation resolution decreased gradually with increasing the volume ratio of the modifier. At the same volume ratio of modifier, the retention factor of the mandelic acid and its derivatives increased in the order of methanol, ethanol, and isopropanol, except 3‐chloromandelic acid. The separation factor and the separation resolution decreased with the increase of column temperature (below the temperature limit). The backpressure affected the enantioseparation process: As the backpressure increased, a corresponding decrease in retention factor was observed. Under the same chiral column conditions, the SFC method exhibited faster and more efficient separation with better enantioselectivity than the HPLC method.
Enantioselective toxic effects and digestion of furalaxyl enantiomers in Scenedesmus obliquus
Authors: Cheng Cheng , Ma Rui , Lu Yuele , Liu Chunxiao , Zhang Wenjun , Di Shanshan , Chen Li , Diao Jinling , Zhou Zhiqiang , Hou Yuxia 
Published: September 2018

AbstractResearch on the enantioselective environmental behavior of chiral pesticides has been a hot spot of environmental chemistry recently. In this study, the acute toxicity and digestion of furalaxyl enantiomers were determined on the aquatic algae Scendesmus obliquus. After exposure for 96 hours, the EC50 values for (S)‐furalaxyl and (R)‐furalaxyl were 13.59 and 15.26 mg/L, respectively. In addition, enantioselectivity was observed from the determined chlorophyll contents and antioxidant enzyme (CAT and SOD) activities of algae cells after exposure to furalaxyl enantiomers for 96 hours. The digestion rate of (S)‐furalaxyl and (R)‐furalaxyl were almost the same in S. obliquus. On the basis of these data, the inactive enantiomers (S)‐ furalaxyl is more toxic than the active one on the non‐target species S. obliquus, indicating that such enantiomeric differences should be taken into consideration in the study of pesticide risk assessment.
Unexpected Structure of a Helical N4‐Schiff‐Base Zn(II) Complex and Its Demetallation: Experimental and Theoretical Studies
Authors: Lamine Walid , Boughdiri Salima , Jeanneau Erwan , Sanglar Corinne , Morell Christophe , Christ Lorraine , Chermette Henry 
Published: September 2018

AbstractA new Zn‐N4‐Schiff base L=((±)‐trans‐N,N’‐Bis(2‐aminobenzylidene)‐1,2‐diaminocyclohexane) complex was synthesized and fully characterized, showing an unexpected self‐assembled double‐stranded helicate structure. The X‐ray crystal analysis of the Zn2L2 complex ((C40H44N8Zn2,CH2Cl2, a=14.2375(3) Å, b=16.7976(4) Å, c=16.1613(4) Å, monoclinic, P21/n, Z=4) shows a centrosymmetrical structure in which zinc atoms are in distorted tetrahedral environments, revealing an M‐ (R, R) left‐handed helicity in its asymmetric unit. However, it was observed that this dinuclear complex is thermodynamically unstable in the presence of small water amounts and undergoes demetallation into free N4‐Schiff base ligand and ZnO nanoparticles. This hydrolysis process was thoroughly identified and monitored through detailed 1H NMR, DOSY NMR analysis. The reaction mechanism of this demetallation event was elucidated by using the DFT method, involving an activation energy smaller than 13 kcal/mol. Besides, a theoretical mechanism of the demetallation process is given for the first time.
High Resolution for Chemical Shifts and Scalar Coupling Constants: The 2D Real‐Time J‐Upscaled PSYCHE‐DIAG
Authors: Tassoti Sebastian , Novak Predrag , Butts Craig P. , Zangger Klaus 
Published: September 2018

AbstractThe facile determination of chemical shift and scalar coupling constants in NMR spectra is often prevented by spectral overlap and limited resolution. Here, we present a high‐resolution NMR experiment for the simultaneous detection of both resonance frequencies and coupling patterns even with small J‐values. A PSYCHE‐decoupled DIAG (Pure Shift Yielded by Chirp Excitation‐ DIAGonal) experiment, which resolves chemical shift in the indirect dimension of a 2D experiment is combined with real‐time J‐upscaling in order to visualize small coupling constants that would otherwise be hidden in the linewidth of a regular proton or DIAG spectrum.
Determination of Thirteen Trace and Toxic Elements in Urine Using Inductively Coupled Mass Spectrometry
Authors: Velez‐Quinones Maria A. , Xu Hanna , Vo Nhu , Gaitens Joanna M. , McDiarmid Melissa A. , Lewin‐Smith Michael R. , Strathmann Frederick G. 
Published: September 2018

AbstractWe developed and validated a method for the assessment of thirteen separate trace and toxic elements using Inductively Coupled Plasma‐Mass Spectrometry (ICP‐MS). Included elements were as follows: aluminum, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, molybdenum, cadmium, tungsten, and lead. The measurements of all elements in urine samples were conducted using ICAP‐Q ICP‐MS in a single method. The performance characteristics of the assay were determined according to clinical laboratory standards. The assay was linear in the concentration range of 1.0 to 1000.0 µg/liter for all elements. The method was precise and accurate with limits of quantitation of 1 µg/liter for chromium, manganese, cobalt, nickel, copper, cadmium, tungsten, and lead; 2 µg/liter for iron and arsenic; 5 µg/liter for aluminum; and 50 µg/liter for zinc. This method has successfully been used for the assessment of all thirteen elements included in urine and has been shown to be effective as a simple, precise, and sensitive analytical technique for biological monitoring of urine samples. © 2018 by John Wiley & Sons, Inc.
Comparison between Modified and Unmodified Carbon Paste Electrodes for Hexavalent Chromium Determination
Authors: Hilali Nazha , Ghanam Abdelghani , Mohammadi Hasna , Amine Aziz , García‐Guzmán Juan José , Cubillana‐Aguilera Laura , Palacios‐Santander José María 
Published: September 2018

AbstractThis work consists of developing a simple electroanalytical method which allows the speciation of Cr(VI). Gold modified Carbon Paste Electrodes (CPEs) and unmodified CPEs have been tested for the determination of Cr(VI) in presence of an excess of Cr(III) by using differential pulse voltammetry (DPV), without any accumulation or pre‐concentration time. Several parameters affecting the analytical performances of the designed electrodes were investigated, including: electrodeposition technique of AuNPs onto the CPE, amount of AuNPs dropped on the electrode surface, supporting electrolyte, presence of Cr(III), presence of chloride ions and concentration of diphenylcarbazide (DPC). Under the optimal conditions, the use of unmodified CPE in an acidic medium containing DPC exhibited a high selectivity and a good detection limit of 19 μg ⋅ L−1, which is much lower than the admissible concentration fixed by the World Health Organization (50 μg ⋅ L−1). A linear range from 50 to 260 μg ⋅ L−1 was obtained with a relative standard deviation of 7.75 %. Furthermore, as opposed to the AuNPs‐modified CPE, the current response of Cr(VI) obtained at the unmodified CPE was not affected by the presence of chloride ions and trivalent chromium. Finally, the proposed method was successfully applied for the determination of Cr(VI) in real tap water samples with satisfactory results.
Protracted river response to medieval earthquakes
Authors: Stolle Amelie , Schwanghart Wolfgang , Andermann Christoff , Bernhardt Anne , Fort Monique , Jansen John D. , Wittmann Hella , Merchel Silke , Rugel Georg , Adhikari Basanta Raj , Korup Oliver 
Published: September 2018

AbstractMountain rivers respond to strong earthquakes by rapidly aggrading to accommodate excess sediment delivered by co‐seismic landslides. Detailed sediment budgets indicate that rivers need several years to decades to recover from seismic disturbances, depending on how recovery is defined. We examine three principal proxies of river recovery after earthquake‐induced sediment pulses around Pokhara, Nepal's second largest city. Freshly exhumed cohorts of floodplain trees in growth position indicate rapid and pulsed sedimentation that formed a fan covering 150 km2 in a Lesser Himalayan basin with tens of metres of debris between the 11th and 15th centuries AD. Radiocarbon dates of buried trees are consistent with those of nearby valley deposits linked to major medieval earthquakes, such that we can estimate average rates of re‐incision since. We combine high‐resolution digital elevation data, geodetic field surveys, aerial photos, and dated tree trunks to reconstruct geomorphic marker surfaces. The volumes of sediment relative to these surfaces require average net sediment yields of up to 4200 t km–2 yr–1 for the 650 years since the last inferred earthquake‐triggered sediment pulse. The lithological composition of channel bedload differs from that of local bedrock, confirming that rivers are still mostly evacuating medieval valley fills, locally incising at rates of up to 0.2 m yr–1. Pronounced knickpoints and epigenetic gorges at tributary junctions further illustrate the protracted fluvial response; only the distal portions of the earthquake‐derived sediment wedges have been cut to near their base. Our results challenge the notion that mountain rivers recover speedily from earthquakes within years to decades. The valley fills around Pokhara show that even highly erosive Himalayan rivers may need more than several centuries to adjust to catastrophic perturbations. Our results motivate some rethinking of post‐seismic hazard appraisals and infrastructural planning in active mountain regions. © 2018 John Wiley & Sons, Ltd.
Fast computation of the wall distance in unsteady Eulerian fluid‐structure computations
Authors: Grimberg Sebastian , Farhat Charbel 
Published: September 2018

SummaryHighly nonlinear, turbulent, dynamic, fluid‐structure interaction problems characterized by large structural displacements and deformations, as well as self‐contact and topological changes, are encountered in many applications. For such problems, the Eulerian computational framework, which is often equipped with an embedded (or immersed) boundary method for computational fluid dynamics, is often the most appropriate framework. In many circumstances, it requires the computation of the time‐dependent distance from each active mesh vertex of the embedding mesh to the nearest embedded discrete surface. Such circumstances include, for example, modeling turbulence using the Spalart‐Allmaras or detached eddy simulation turbulence models and performing adaptive mesh refinement in order to track the boundary layer. Evaluating at each time step the distance to the wall is computationally prohibitive, particularly in the context of explicit‐explicit fluid‐structure time‐integration schemes. Hence, this paper presents two complementary approaches for reducing this computational cost. The first one recognizes that many quantities depending on the wall distance are relatively insensitive to its inaccurate evaluation in the far field. Therefore, it simplifies a state‐of‐the‐art algorithm for computing the wall distance accordingly. The second approach relies on an effective wall distance error estimator to update the evaluation of the wall distance function only when otherwise, a quantity of interest that depends on it would become tainted by an unacceptable level of error. The potential of combining both approaches for dramatically accelerating the computation of the wall distance is demonstrated with the Eulerian simulation of the inflation of a disk‐gap‐band parachute system in a supersonic airstream.
Financing health care in Bangladesh: Policy responses and challenges towards achieving universal health coverage
Authors: Fahim Shah Mohammad , Bhuayan Tofayel Ahmed , Hassan Md. Zakiul , Abid Zafr Abu Hena , Begum Farhana , Rahman Md. Mizanur , Alam Shahinul 
Published: September 2018

SummaryBangladesh has attained notable progress in most of the health indicators, but still, health system of the country is suffering badly from poor funding. Issues like burden of out‐of‐pocket expenditure, low per capita share in health, inadequate service facilities, and financial barriers in reducing malnutrition are being overlooked due to inadequacy and inappropriate utilization of allocated funds. We aimed to review the current status of health care spending in Bangladesh in response to national health policy (NHP) and determine the future challenges towards achieving universal health coverage (UHC). National health policy suggested a substantial increase in budgetary allocation for health care, although government health care expenditures in proportion to total public spending plummeted down from 6.2% to 4.04% in the past 8 years. Overall, 67% of the health care cost is being paid by people, whereas global standard is below 32%. Only one hospital bed is allocated per 1667 people, and 34% of total posts in health sector are vacant due to scarcity of funds. The country is experiencing demographic dividend with a concurrent rise of aged people, but there seems no financial protection schemes for the aged and working age populations. Such situation results in multiple obstacles in achieving financial risk protection as well as UHC. Policy makers must think effectively to develop and adapt systems in order to achieve UHC and ensure health for all.
Does ethnic identity buffer or intensify the stress of discrimination among the foreign born and U.S. born? Evidence from the Miami‐Dade Health Survey
Authors: Mossakowski Krysia N. , Wongkaren Turro , Hill Terrence D. , Johnson Robert 
Published: September 2018

AbstractThis study examines the extent to which ethnic identity is a protective factor and buffers the stress of discrimination among the foreign born compared to the U.S. born in Miami‐Dade County. Data were drawn from the 2011 Miami‐Dade Health Survey (N = 444), which is a countywide probability sample of adults in South Florida. Two interaction effects were observed: (a) a stronger ethnic identity was associated with less distress among the foreign born than the U.S. born; and (b) a stronger ethnic identity exacerbated the relationship between everyday discrimination and distress among the U.S. born. Ethnic identity, which involves ethnic pride, participation in cultural practices, and cultural commitment or sense of belonging, was associated with better psychological well‐being among the foreign born than the U.S. born. Ethnic identity, however, was not a protective factor for the U.S. born, but rather it intensified the distressing effect of discrimination.
Determination of siloxanes in water samples employing graphene oxide/Fe3O4 nanocomposite as sorbent for magnetic solid‐phase extraction prior to GC–MS
Authors: Costa dos Reis Luciana , Vidal Lorena , Canals Antonio 
Published: September 2018

AbstractA new, fast, simple, and environmentally friendly analytical method has been developed to determine six siloxanes in water samples: octamethyltrisiloxane, octamethylcyclotetrasiloxane, decamethyltetrasiloxane, decamethylcyclopentasiloxane, dodecamethylpentasiloxane and dodecamethylcyclohexasiloxane. The analytical method consists of magnetic solid‐phase extraction employing graphene oxide/Fe3O4 as sorbent for the separation and preconcentration of siloxanes prior to GC–MS determination. The extraction procedure was optimized by means of a Plackett‐Burman design. Under the optimized extraction conditions (graphene oxide/Fe3O4, 20 mg; extraction time, 10 min; eluent volume, 0.5 mL ACN; elution time, 2.5 min; sample volume, 20 mL), the method rendered repeatability levels with a relative standard deviation between 9 and 20% (n = 6, 10 μg/L). Methodological limits of detection ranged from 0.003 to 0.1 μg/L. The linearity of the method was studied between the methodological limit of quantification and 100 μg/L, obtaining correlation coefficient values between 0.990 and 0.999. The applicability of the method was assessed by analyzing drinking, river and wastewater samples. Relative recovery values ranged between 70 and 120% (1 and 60 μg/L spiking level) showing that the matrix had a negligible effect on extraction. Finally, the greenness of this method was confirmed by the semiquantitative Eco‐Scale metrics.
Facile Synthesis of Single‐Hole Crosslinked Particles with Embedded Single Bulge by Seeded Emulsion Polymerization
Authors: Sun Xu , Huang Ying , Chen Menghua , Peng Xuanyi , Dou Wenjie 
Published: September 2018

AbstractRecently, anisotropic particles with single‐hole or open‐mouth structures have been the significant support platform because they provide the contact channel for the target molecules and substrate. However, the powerless synthetic methods severely restrict the preparation efficiency and further application. Herein, a facile, and large‐scale seeded emulsion polymerization procedure is developed for controlling preparation of crosslinked PGMA/PDVB particles with controlled single hole. The morphology evolution from spotted particles to dimple particles to bulge‐in‐hole particles is investigated in detail. More importantly, this strategy opens up a novel avenue for fabricating single‐hole particles with controlled openings for encapsulation and capsulation.
A method to estimate transmission profiles of bow‐tie filters using rotating tube measurements
Authors: Al‐Senan Rani 
Published: September 2018

PurposeThe purpose of this paper was to present a method of determining the dose profile of the beam bow‐tie filter (BTF) without the need for fixing the x ray tube in a position or using special instruments or dosimeters other than the ordinary types of ion chambers used for CT dosimetry (e.g., Farmer chamber).MethodsThe idea behind this method is to try to invert the integral of exposures from axial measurements by decomposing it into fractions per degree of tube rotation. Measurements of the CT tube output were taken with a full tube rotation while the chamber was fixed in air. Starting with isocenter the output measurements were performed at 1‐cm interval above the isocenter. Measurements were repeated for three sizes of BTFs; small, medium, and large. Maximum fan angle per chamber position was computed and an effective fan angle was defined to account for the new angular range encountered per chamber position. Variation due to inverse‐square law was isolated from each measurement and contribution from the effective fan angle was computed. Resulted profiles from this method were then compared to profiles obtained with direct measurements, when the tube was in a fixed position. Effects of over and under 360° rotation per scan on results accuracy were also investigated.ResultsUsing the direct measurements as the gold standard, results from this method were accurate to 4% for most of the BTFs angular ranges. The average relative error in the small BTF was 1.5%. In the medium BTF, the average relative error was <3% for up to 16° fan angle. With the large BTF, the mean error was about 4% for up to 22°. The relative error appeared to increase at larger fan angles especially with the large BTF; reaching an average of about 32% for fan angles between 22° and 27.5°.ConclusionThe presented method is relatively easy to perform and provides BTFs profiles with reasonably good accuracy. Associated errors of >10% only appear in high angles of large and medium BTFs.