bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and validation of an endoscopic ear surgery classification system
Authors: Cohen Michael S. , Basonbul Razan A. , Barber Samuel R. , Kozin Elliott D. , Rivas Alejandro C. , Lee Daniel J. 
Published: August 2017

Objectives/HypothesisTo design and validate a classification system for endoscopic ear surgery.Study DesignValidation study.MethodsA classification system was devised that quantifies use of the endoscope during middle ear surgery. Otologic operative reports were reviewed by attending surgeons and trainees. A power analysis was performed to determine number of cases needed to review. The following categories were used: class 0 is defined by using the microscope only; class 1 describes the use of endoscope for inspection without dissection; and class 2 describes mixed use of the endoscope and the microscope. It is further subdivided into 2a and 2b, where the endoscope is used for less than 50% of dissection and more than 50% of dissection, respectively. Class 3 describes the use of the endoscope for the entire surgery. Fifty cases were reviewed by three attending otologic surgeons, one resident, and one medical student.ResultsWeighted Cohen's Kappa for inter‐rater agreement between the two institutional surgeons was 0.79 (95% bias corrected [BC] confidence interval [CI]: 0.58‐0.93). Agreement between the external surgeon and the two institutional surgeons was 0.77 (95% BC CI: 0.58‐0.89) and 0.76 (95% BC CI: 0.57‐0.88). Weighted Kappa between institutional surgeons and a resident was 0.73 (95% BC CI: 0.53‐0.88) and 0.62 (95% BC CI: 0.38‐0.80), and between institutional surgeons and a medical student was 0.75 (95% BC CI: 0.56‐0.89) and 0.70 (95% BC CI: 0.49‐0.85).ConclusionsThere was substantial inter‐rater agreement. This classification system can be used as a simple and reliable tool to describe the extent to which an endoscope was used during ear surgery.Level of EvidenceNA. Laryngoscope, 128:967–970, 2018
Tracing Pb Pollution Penetration in Temperate Podzols
Authors: Ferro‐Vázquez Cruz , Pérez‐Rodríguez Marta , Nóvoa‐Muñoz Juan Carlos , Klaminder Jonatan , Bindler Richard , Martínez Cortizas Antonio 
Published: August 2017

AbstractWe combine high‐resolution soil sampling with lead (Pb) analyses (concentrations and stable isotopes) in two temperate podzols, together with previous data obtained with selective Al and Fe dissolution techniques. We aim to assess how atmospheric Pb is incorporated into the soils during pedogenesis. Partial least squares modelling for Pb concentrations shows that the podzolization process has the largest effect on Pb concentration (80·3% of the variance). The proportion of inorganic secondary compounds, the input of fresh organic matter from the soil surface and the relative abundance of Fe versus Al are responsible for a small part of the Pb concentration variance. Lead isotopic composition (206Pb/207Pb ratios) depends on soil organic matter content either fresh/poorly humified (57·3% of the variance) or humified (24·7% of the variance). The Pb linked to inorganic compounds and the overall podzolization process play a minor role in isotopic signature (5·3 and 3·7% of the variance respectively). Soil pH appears to be the controlling variable of the different transport and retention mechanisms. The relatively low isotopic ratios observed in spodic horizons result from geogenic Pb released through the preferential dissolution of the isotopically distinct most weatherable minerals of the parent material in the eluvial horizons, which undergoes downward mobilization. An accurate knowledge of soil reactive components and formation mechanisms is essential to a correct diagnose of the scope of Pb pollution and a more effective design of remediation strategies. Copyright © 2017 John Wiley & Sons, Ltd.
Spontaneous Self‐Assembly and Micellization of Random Copolymers in Organic Solvents
Authors: Sadeghi Ilin , Asatekin Ayse 
Published: August 2017

AbstractSpontaneous self‐assembly of random and statistical copolymers in solution, especially in organic solvents, is unusual due to the structural irregularity of the copolymer chain and close proximity of short incompatible segments. This study describes the first observation of supramolecular structures such as micelles and vesicles formed by a random copolymer in organic solvents. Upon dissolution in methanol or tetrahydrofuran, the random copolymer poly(trifluoroethyl methacrylate‐random‐methacrylic acid) forms small spherical micelles, worm‐like assemblies, and large vesicles spontaneously. Self‐assembly is driven by the high incompatibility between the fluorinated and acidic repeat units. Micelle size can also be altered by the addition of metal ions, which interact with the carboxylic acid groups of methacrylic acid through complexation or Coulombic forces. These findings demonstrate an easy, single‐step approach to creating nanoscale structures with tunable size and morphologies in organic solvents from easily synthesized random copolymers, with potential applications in coatings, selective membranes, catalysis, and drug delivery.
Molecular evolution of acetohydroxyacid synthase in bacteria
Authors: Liu Yadi , Li Yanyan , Wang Xiaoyuan 
Published: August 2017

AbstractAcetohydroxyacid synthase (AHAS) is the key enzyme in the biosynthetic pathways of branched chain amino acids in bacteria. Since it does not exist in animal and plant cells, AHAS is an attractive target for developing antimicrobials and herbicides. In some bacteria, there is a single copy of AHAS, while in others there are multiple copies. Therefore, it is necessary to investigate the origin and evolutionary pathway of various AHASs in bacteria. In this study, all the available protein sequences of AHAS in bacteria were investigated, and an evolutionary model of AHAS in bacteria is proposed, according to gene structure, organization and phylogeny. Multiple copies of AHAS in some bacteria might be evolved from the single copy of AHAS, the ancestor. Gene duplication, domain deletion and horizontal gene transfer might occur during the evolution of this enzyme. The results show the biological significance of AHAS, help to understand the functions of various AHASs in bacteria, and would be useful for developing industrial production strains of branched chain amino acids or novel antimicrobials.
A theoretical and NMR lanthanide‐induced shift (LIS) investigation of the conformations of lactams.
Authors: Abraham Raymond J. , Filippi Marco , Petrillo Giovanni , Piaggio Paola , Vladiskovic Chiara , Sancassan Fernando 
Published: August 2017

Molecular mechanics (MM) with MMFF94 and MMX force fields and ab initio (RHF/6‐31G*,RHF/6‐311G**, and B3LYP/6‐311G**) calculations are used with lanthanide‐induced shift (LIS) to investigate the conformations of N‐methyl‐2‐pyrrolidone 1, N‐methyl‐2‐piperidone 2, ε‐caprolactam 3, γ‐valerolactam (1,5‐dimethyl‐2‐pyrrolidone) 4, 2‐azetidinone 5, 4‐methyl azetidinone 6, 4‐phenyl azetidinone 7, and N‐methyl‐4‐phenyl azetidinone 8. The Yb(fod)3 paramagnetic induced shifts of all the 1H and 13C nuclei are measured and the corresponding diamagnetic complexation shifts obtained by the addition of Lu(fod)3. The complexation model (two‐, three‐, or four‐site) used depends on the relative rates of the processes involved. The amide inversion is the same order as that of the 5‐ and 6‐membered lactam rings and much faster than the lanthanide complexation and the inversion of the 7‐membered ring.Both MM and ab initio calculations give an envelope conformation for 1 with C‐4 out of the ring plane in agreement with the LIS analysis. For the piperidone ring of 2, the half‐chair is calculated as the most stable form. The LIS analysis confirms this but cannot exclude a small amount (<2%) of the boat conformation. For 3, the LIS analysis gives a minimum for 90:10% chair to boat conformation, and 4 exists in two envelope conformations with the C5‐Me ps‐eq and ps‐ax in an eq/ax ratio of 94:6%. In 2‐azetidinone 5, the ab initio calculations gave both ring and nitrogen planar, but the MMFF94 calculations give a butterfly ring and pyramidal nitrogen. The LIS analysis for 5 gave good agreement (Rcryst 0.46%) for the MMFF94 geometry with endo NH but the planar ab initio geometries worse agreement (Rcryst = 1.1%). For 4‐methyl‐2‐azetidinone 6, the MMFF94 geometry gave good agreement (Rcryst 0.96%) with two butterfly conformations with axial and equatorial methyl groups in 1:1 ratio. All the planar geometries gave worse agreement (Rcryst >1.5%). In 4‐phenyl azetidinone 7, the MMFF94 geometry with 60% of the axial conformer gave Rcryst 1.2% but the other geometries Rcryst >1.5%. In contrast the N‐methyl‐4‐phenyl‐2‐azetidinone 8 gave good agreement for all the geometries. The butterfly conformation gave Rcryst 1.1% for 80% of the axial conformer and the planar geometries Rcryst 0.98%. The LIS results confirm the ab initio and MM optimised geometries, but the conformer energies at times differ from the calculated values. They also differ considerably from the corresponding values for the lactones studied previously, and possible reasons for this are discussed.
Silent navigator–triggered silent MRI of the abdomen
Authors: Iwadate Yuji , Nozaki Atsushi , Nunokawa Yoshinobu , Okuda Shigeo , Jinzaki Masahiro , Kabasawa Hiroyuki 
Published: August 2017

PurposeTo develop and demonstrate the feasibility of a silent respiratory navigator technique for prospective triggering, which was incorporated into a three‐dimensional radial zero‐echo‐time sequence for respiratory navigated silent abdominal imaging.MethodsA nonselective hard excitation radiofrequency pulse was used for the navigator sequence with a derated readout gradient, to avoid generation of high levels of acoustic noise. The acquired navigator signals were processed in real time and used for prospective triggering of the zero‐echo‐time sequence. Ten healthy volunteers were scanned using the proposed and conventional techniques at 1.5 T. An acoustic noise measurement with A‐weighted continuous equivalent sound pressure level was also performed.ResultsThe sound pressure–level values of the background noise, zero‐echo‐time imaging, conventional, and silent navigators were 68.3, 68.4, 102.5, and 69.4 dBA, respectively. Excellent correlation with correlation coefficients greater than 0.9 was observed between the bellows signals and displacement values calculated from the navigators. Sharpness of the portal vein of both conventional and silent navigator–triggered images was significantly higher than those of nontriggered images.ConclusionsThe silent navigator–triggered zero‐echo‐time technique is feasible and might improve image quality and workflow of abdominal MRI of patients who are prone to acoustic noise. Magn Reson Med 79:2170–2175, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Minimally invasive measurement of vesical pressure for diagnosis of infravesical obstruction
Authors: de Almeida João C. M. , D'Ancona Carlos A. L. , Bassani José W. M. 
Published: August 2017

AimsThis study was focused on the clinical test of an improved and portable version of a previously described urethral connector (UC), designed for minimally invasive measurement of vesical pressure and diagnosis of infravesical obstruction in men.MethodsThe conventional pressure‐flow study (PFS) and the test with the new version of UC were applied to individuals reporting lower urinary tract symptoms (LUTS), who were then classified as obstructed or non‐obstructed/equivocal based on the bladder outlet obstruction index (BOOI) from PFS data. Two‐way analysis of variance was used to compare the values of urine flow rate and vesical pressure between methods and diagnoses.ResultsVesical pressure and urine flow values were not significantly different between methods (P > 0.05), while the former was greater in the group classified as obstructed.ConclusionThe present results showed that the UC test can support the diagnosis of infravesical obstruction in a comparable way as that of the conventional urodynamic method, however with the advantages of simplicity and minimal invasiveness, having thus the potential to be an alternative method for long term follow‐up of individuals reporting LUTS.
A weighted singular value decomposition for the discrete inverse problems
Authors: Jozi Meisam , Karimi Saeed 
Published: August 2017

SummaryIn this paper, we introduce and analyze a new singular value decomposition (SVD) called weighted SVD (WSVD) using a new inner product instead of the Euclidean one. We use the WSVD to approximate the singular values and the singular functions of the Fredholm integral operators. In this case, the new inner product arises from the numerical integration used to discretize the operator. Then, the truncated WSVD (TWSVD) is used to regularize the Nyström discretization of the first‐kind Fredholm integral equations. Also, we consider the weighted LSQR (WLSQR) to approximate the solution obtained by the TWSVD method for large problems. Numerical experiments on a few problems are used to illustrate that the TWSVD can perform better than the TSVD.
Voltage Oscillations in a Polymer Electrolyte Membrane Fuel Cell with Pd‐Pt/C and Pd/C Anodes
Authors: Nogueira Jéssica Alves , Varela Hamilton 
Published: August 2017

AbstractPolymer electrolyte membrane fuel cells (PEMFC) fed with H2contaminated with CO may exhibit oscillatory behavior when operated galvanostatically. The self‐organization of the anodic overpotential is interesting because it can be accompanied by an increase in the average performance. Herein we report experimental studies of voltage oscillations that emerge in a PEMFC equipped with a Pd/C or PdPt/C anode and fed with H2contaminated with CO (100 ppm). We used on‐line mass spectrometry to investigate how the mass fragments associated with CO2and CO (m/z44 and 28, respectively) varied with the voltage oscillations. Overall, we observed that oscillations in the anodic overpotential are in phase with that of the CO and CO2signals. This fact is consistent with an autonomous adsorption–oxidation cyclic process. For both anodes, it has been observed that, in general, an increase in current density implies an increase in oscillatory frequency. By using CO stripping, we also discuss how the onset of CO oxidation is related to the maximum overpotential reached during a cycle, whereas the minimum overpotential can be associated with the catalytic activity of the electrode for H2oxidation.
Internalizing and externalizing in adolescence: the roles of academic self‐efficacy and gender
Authors: Rocchino Gabrielle H. , Dever Bridget V. , Telesford Alana , Fletcher Kristen 
Published: August 2017

AbstractThis study examines academic self‐efficacy and gender as predictors of internalizing and externalizing behaviors in adolescence. In addition, the role of gender was considered as a moderator in the relationship between academic self‐efficacy and internalizing/externalizing difficulties. Participants were 4,318 predominantly African American, low‐income high school students who completed self‐report measures on the constructs of interest. Academic self‐efficacy and gender were both significant predictors of risk for internalizing problems, whereas only academic self‐efficacy predicted risk for externalizing (hyperactivity/distractibility) problems. Gender did not predict externalizing difficulties, nor did gender serve as a moderator in any analysis. Implications include focusing on academic self‐efficacy in the development of strategies for prevention and intervention of internalizing and externalizing problems.
From Peptide Masses to Pregnancy Maintenance: A Comprehensive Proteomic Analysis of The Early Equine Embryo Secretome, Blastocoel Fluid, and Capsule
Authors: Swegen Aleona , Grupen Christopher G. , Gibb Zamira , Baker Mark A. , de Ruijter‐Villani Marta , Smith Nathan D. , Stout Tom A. E. , Aitken R. John 
Published: August 2017

AbstractEarly pregnancy in the mare is a poorly understood, high risk period during which the embryo communicates its presence to the maternal endometrium. Remarkably, the maternal recognition of pregnancy signal is unknown in the horse. This study aimed to profile the proteins secreted by equine blastocysts into their immediate environment, along with proteins contained in the blastocoel and within the acellular embryo capsule. Embryos were recovered on day 8 after ovulation and cultured for 48 hours. Secretomes of day 9 and day 10 embryos were analyzed by LC‐MS/MS and supported by analysis of blastocoel fluid and embryo capsule. Analyses revealed 72 (24 h) and 97 (48 h) unique protein IDs in the embryo secretome, 732 protein IDs in blastocoel fluid, and 11 proteins IDs in the embryo capsule. Novel findings of interest include secretion of a pregnancy specific proteinase (PAG) by the equine embryo at day 10, along with detection of a prostaglandin receptor inhibiting protein (PTGFRN) and a progesterone potentiating factor (FKBP4) in blastocoel fluid. This is the first comprehensive proteomic analysis of the equine embryo secretome, and provides new insights into the unique physiology of early pregnancy in this species.
Preparation and characterization of layer‐by‐layer self‐assembly membrane based on sulfonated polyetheretherketone and polyurethane for high‐temperature proton exchange membrane
Authors: Yu Jinming , Cheng Shicheng , Che Quantong 
Published: August 2017

ABSTRACTA concept of preparing high‐temperature proton exchange membranes with layer‐by‐layer (LBL) self‐assembly technique was proposed and the sulfonated polyetheretherketone (SPEEK) and polyurethane (PU) with 200 LBL deposition cycles denoting (SPEEK/PU)200membrane was prepared in this research. Owing to the strong electrostatic interaction between group in SPEEK and CN+group in PU, (SPEEK/PU)200membrane with LBL self‐assembly structure showed a favorable structural stability. The phosphoric acid (PA)‐doped (SPEEK/PU)200membrane showed a higher proton conductivity relative to PA doped SPEEK/PU membrane by solution casting method (SPEEK/PU)200/40%PA membrane possessed a proton conductivity value of 2.90 × 10−2S/cm at 150 °C under anhydrous conditions. The LBL self‐assembly structure provided a possibility to reduce the negative effect from polymer skeleton blocking charge carrier species even immobilizing protons. Moreover, the (SPEEK/PU)200membrane presented the particularly noteworthy mechanical property even with PA doping. The tensile stress values at break were 72.8 and 24.1 MPa, respectively, for (SPEEK/PU)200and (SPEEK/PU)200/40%PA membrane at room temperature, which were obviously higher than the reported values of 15.9 and 2.81 MPa for SPEEK/PU and SPEEK/PU/60%PA membrane. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2017,55, 3446–3454
Carbon nanofibers/polypyrrole nano metacomposites
Authors: Kou Xuechen , Yao Xiuchao , Qiu Jun 
Published: August 2017

ABSTRACTCarbon nanofibers (CNFs)/polypyrrole (PPy) nano metacomposites are prepared by in situ polymerization in this article. The negative permittivity and negative permeability of CNFs/PPy nano metacomposites are achieved simultaneously. CNFs/PPy composites form different morphologies with the increase in CNFs content. Complex conductive networks formed by overlapped CNFs are present in CNFs/PPy composites with 30 and 50 wt % CNFs. The negative permittivity of the CNFs/PPy composites is attributed to the plasma oscillation of delocalized electrons, and the negative permeability results from a large number of conductive loops. The appearance of negative permeability is accompanied by the decrease in resistivity, which reflects that a large number of conductive loops are derived from complex conductive networks. Double negative property appears in the frequency range 845–1000 MHz in CNFs/PPy composites with 30 wt % CNFs content and 825–1000 MHz in CNFs/PPy composites with 50 wt % CNFs content. CNFs/PPy composites present double negative property in a wider frequency range compared with MWCNTs/PPy nanocomposites. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1724–1729
A cautionary note on the effects of laboratory air contaminants on ambient ionization mass spectrometry measurements
Authors: Kumbhani Sambhav R. , Wingen Lisa M. , Perraud Véronique , Finlayson‐Pitts Barbara J. 
Published: August 2017

RationaleAmbient ionization mass spectrometry methods are convenient, sensitive and require little sample preparation. However, they are susceptible to species present in air surrounding the mass spectrometer. This study identifies some challenges associated with the potential impacts of indoor air contaminants on ionization and analysis involving open‐air methods.MethodsUnexpected effects of volatile organic compounds (VOCs) from floor maintenance activities on ambient ionization mass spectrometry were studied using three different ambient ionization techniques. Extractive electrospray ionization (EESI), direct analysis in real time (DART) and ionization by piezoelectric direct discharge (PDD) plasma were demonstrated in this study to be affected by indoor air contaminants. Identification of contaminant vapors was verified by comparison with standards using EESI‐MS/MS product ion scans.ResultsEmissions of diethylene glycol monoethyl ether and ethylene glycol monobutyl ether are identified from floor stripping and waxing solutions using three ambient ionization mass spectrometry techniques. These unexpected indoor air contaminants are capable of more than 75% ion suppression of target analytes due to their high volatility, proton affinity and solubility compared with the target analytes. The contaminant vapors are also shown to form adducts with one of the target analytes.ConclusionsThe common practice in MS analysis of subtracting a background air spectrum may not be appropriate if the presence of ionizable air contaminants alters the spectrum in unexpected ways. For example, VOCs released into air from floor stripping and waxing are capable of causing ion suppression of target analytes.
Fast terminal sliding‐mode finite‐time tracking control with differential evolution optimization algorithm using integral chain differentiator in uncertain nonlinear systems
Authors: Ma Ruizi , Zhang Guoshan , Krause Olav 
Published: August 2017

SummaryThis paper presents a fast terminal sliding‐mode tracking control for a class of uncertain nonlinear systems with unknown parameters and system states combined with time‐varying disturbances. Fast terminal sliding‐mode finite‐time tracking systems based on differential evolution algorithms incorporate an integral chain differentiator (ICD) to feedback systems for the estimation of the unknown system states. The differential evolution optimization algorithm using ICD is also applied to a tracking controller, which provides unknown parametric estimation in the limitation of unknown system states for trajectory tracking. The ICD in the tracking systems strengthens the tracking controller robustness for the disturbances by filtering noises. As a powerful finite‐time control effort, the fast terminal sliding‐mode tracking control guarantees that all tracking errors rapidly converge to the origin. The effectiveness of the proposed approach is verified via simulations, and the results exhibit high‐precision output tracking performance in uncertain nonlinear systems.