bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photonic crystal bandpass filter exploiting the degenerate modes tunable with MEMS actuator for terahertz application
Authors: Karakilinc Ozgur Onder , Tez Serdar , Kaya Mehmet 
Published: March 2021

AbstractIn this study, the bandpass filter characteristics in standing wave resonator formed in a two‐dimensional (2D) photonic crystal (PC) is integrated with microelectromechanical systems (MEMS) actuator to tune degenerate mode split. A single and sequentially connected indirect coupling structure consisting of waveguide as well as cavity is placed to the 2D PC. It has been shown that the modes of the bands can be split by structural deformation of the PC via MEMS actuator. The modes frequencies can be changed with the bias voltage applied to MEMS structure, which allows to tune about 1 THz (λ = 35 nm). The designed PC and MEMS structures are analyzed with simulation programs using finite difference time domain method and finite element method, respectively. The proposed PC structures can be effectively used in new generation all optical THz communication applications.
Application of piezoelectric transducers in photoacoustic spectroscopy for trace gas analysis
Authors: Lv Haohua , Luo Huijian , Zheng Huadan , Zhu Wenguo , Fang Junbin , Yu Jianhui , Tittel Frank , Chen Zhe 
Published: March 2021

AbstractPhotoacoustic spectroscopy (PAS) is a boomingly developed spectroscopic method for trace gas analysis in the past decades. Unlike traditional laser absorption spectroscopy, an acoustic transducer is employed to detect the acoustic waves instead of optical waves. Microphone is a commonly used transducer to convert the acoustic signal into electrical signal, which is related to the gas concentration. In recent years, piezoelectric materials are playing important roles in the acoustic‐to‐electrical conversion process of photoacoustic system. In this article, recently used transducers in PAS such as quartz tuning fork, polyvinylidene fluoride, lead zirconate titanate, electromechanical film and LiNbO3, BiB3O6, NbCOB crystals are summarized and discussed in detail. The different spectrophone configuration, schematic diagram, and experimental system are reported. Side by side comparison is carried out to show the gas sensing performance of these piezoelectric transducers.
NMR relaxometry analysis of molecular degradation in internal combustion engine lubricants
Authors: Erro Eustaquio M. , Gerbino Leandro J. , Fraenza Carla C. , Anoardo Esteban 
Published: March 2021

AbstractA set of experimental techniques headed by proton fast field‐cycling nuclear magnetic resonance (1HFFC‐NMR) were used to analyze the effects of degradation of lubricant oil used in an internal combustion engine (ICE). Its relaxometric, spectroscopic, and rheological properties were evaluated and interpreted in terms of changes in the chemical structure and the involved molecular dynamics. In order to better understand the relaxometric behavior, chemical changes induced by heat were investigated for selected n‐alkanes, as model‐systems due to their structural simplicity. Fourier transform infrared (FTIR) spectroscopy, viscosity measurements, and foaming were used to contrast NMR relaxometry experiments. Main observed changes associated with oil degradation can be attributed to molecular oxidation, fragmentation, and ramification. As an outstanding feature of this work, we show that the relaxometric analysis can be done without any special treatment of the sample, allowing results in less than 10 min.
Quantum chemical calculations of77Se and125Te nuclear magnetic resonance spectral parameters and their structural applications
Authors: Rusakova Irina L. , Rusakov Yuriy Yu. 
Published: March 2021

AbstractAn accurate quantum chemical (QC) modeling of77Se and125Te nuclear magnetic resonance (NMR) spectra is deeply involved in the NMR structural assignment for selenium and tellurium compounds that are of utmost importance both in organic and inorganic chemistry nowadays due to their huge application potential in many fields, like biology, medicine, and metallurgy. The main interest of this review is focused on the progress in QC computations of77Se and125Te NMR chemical shifts and indirect spin–spin coupling constants involving these nuclei. Different computational methodologies that have been used to simulate the NMR spectra of selenium and tellurium compounds since the middle of the 1990s are discussed with a strong emphasis on their accuracy. A special accent is placed on the calculations resorting to the relativistic methodologies, because taking into account the relativistic effects appreciably influences the precision of NMR calculations of selenium and, especially, tellurium compounds. Stereochemical applications of quantum chemical calculations of77Se and125Te NMR parameters are discussed so as to exemplify the importance of integrated approach of experimental and computational NMR techniques.
Joint image and field map estimation for multi‐echo hyperpolarized 13C metabolic imaging of the heart
Authors: Traechtler Julia , Vishnevskiy Valery , Fuetterer Maximilian , Kozerke Sebastian 
Published: March 2021

PurposeImage reconstruction of metabolic images from hyperpolarized 13C multi‐echo data acquisition is sensitive to susceptibility‐induced phase offsets, which are particularly challenging in the heart. A model‐based framework for joint estimation of metabolite images and field map from echo shift–encoded data is proposed. Using simulations, it is demonstrated that correction of signal spilling due to incorrect decomposition of metabolites and geometrical distortions over a wide range of off‐resonance gradients is possible. In vivo feasibility is illustrated using hyperpolarized [1‐13C]pyruvate in the pig heart.MethodsThe model‐based reconstruction for multi‐echo, multicoil data was implemented as a nonconvex minimization problem jointly optimizing for metabolic images and B0. A comprehensive simulation framework for echo shift–encoded hyperpolarized [1‐13C]pyruvate imaging was developed and applied to assess reconstruction performance and distortion correction of the proposed method. In vivo data were obtained in four pigs using hyperpolarized [1‐13C]pyruvate on a clinical 3T MR system with a six‐channel receiver coil. Dynamic images were acquired during suspended ventilation using cardiac‐triggered multi‐echo single‐shot echo‐planar imaging in short‐axis orientation.ResultsSimulations revealed that off‐resonance gradients up to ±0.26 ppm/pixel can be corrected for with reduced signal spilling and geometrical distortions yielding an accuracy of ≥90% in terms of Dice similarity index. In vivo, improved geometrical consistency (10% Dice improvement) compared to image reconstruction without field map correction and with reference to anatomical data was achieved.ConclusionJoint image and field map estimation allows addressing off‐resonance‐induced geometrical distortions and metabolite spilling in hyperpolarized 13C metabolic imaging of the heart.
Is cerebrospinal fluid amyloid‐β42 a promising biomarker of response to nusinersen in adult spinal muscular atrophy patients?
Authors: Introna Alessandro , Milella Giammarco , D'Errico Eustachio , Fraddosio Angela , Scaglione Gaspare , Ucci Maria , Ruggieri Maddalena , Simone Isabella Laura 
Published: March 2021

AbstractIntroductionNusinersen was approved as the first treatment for all types of spinal muscular atrophy (SMA), including adults with SMA types 2 and 3. Robust biomarkers of treatment response in SMA adults are lacking. Our aim was to examine cerebrospinal fluid (CSF) amyloid‐β40 (Aβ40) and amyloid‐β42 (Aβ42) peptides as biomarkers of treatment response.MethodsEight patients with SMA types 2 and 3 were recruited consecutively in a single‐center study. CSF was sampled at baseline, after a loading dose, and after three maintenance doses. Levels of Aβ42 and Aβ40 were evaluated for each CSF sampling. Wilcoxon matched‐pairs signed‐rank test was used to detect longitudinal changes.ResultsCSF levels of Aβ42 increased from baseline to day 420 (95% confidence interval, P = .018), with a significant increase at days 180 and 420 compared with days 0 and 300, respectively (95% confidence interval, P = .012 and P = .018).DiscussionThe maintenance and promotion of wellness of residual motor neurons mediated by the restored level of SMN protein due to nusinersen could result in an increased level of amyloid peptides.
Revealing of process–structure–property relationships of fine polypropylene fiber mats generated via melt blowing
Authors: Kara Yahya , Molnár Kolos 
Published: March 2021

AbstractIn this study, we presented systematic and comparative investigations on the structure of polypropylene fibers generated using different processing conditions via melt blowing. Increasing air pressure, die‐to‐collector distance, and air temperature reduced the average fiber diameter nearly 3‐fold, 2‐fold, and 1.75‐fold, respectively. An average of 1.4 μm Feret‐diameter was observed as the smallest pore size, while the fiber mat solidities ranged from 8 to 13%. Differential scanning calorimetry results showed single melting peaks in the 1st heating cycle and double melting peaks in the second one, due to the phase transition at melt blowing. The fiber crystallinities varied between 43 and 52% by changing the processing conditions. The X‐ray diffraction study revealed that the MB fibers exhibited α and mesomorphic crystals depending on the processing parameters. The reference polypropylene sheet made of the same fiber grade polypropylene resin, on the other hand, exhibited a mix of α and γ crystalline forms. The polypropylene fiber mat tensile strength improved by 48% and by 13% with increasing air pressure and air temperature, respectively. Decreasing fiber collection distances resulted in 2.5‐fold higher tensile strength while strain at break reduced eightfold. A new factor, mat consolidation coefficient, was introduced and used to efficiently summarize melt‐blown fiber mats' process–property–structure relationships. This study details how to control the melt blowing parameters to tailor the polypropylene fiber mat features for the respective application field. It also presents an insight into fiber formation mechanisms during melt blowing for generating self‐bonded, defect‐free, fine fiber mats.
Extracorporeal treatments for isoniazid poisoning: Systematic review and recommendations from the EXTRIP workgroup
Authors: Mowry James B. , Shepherd Greene , Hoffman Robert S. , Lavergne Valery , Gosselin Sophie , Nolin Thomas D. , Vijayan Anitha , Kielstein Jan T. , Roberts Darren M. , Ghannoum Marc ,   for the Extracorporeal Treatments in Poisoning workgroup
Published: March 2021

AbstractIsoniazid toxicity from self‐poisoning or dosing errors remains common in regions of the world where tuberculosis is prevalent. Although the treatment of isoniazid poisoning is centered on supportive care and pyridoxine administration, extracorporeal treatments (ECTRs), such as hemodialysis, have been advocated to enhance elimination of isoniazid. No systematic reviews or evidence‐based recommendations currently exist on the benefit of ECTRs for isoniazid poisoning. The Extracorporeal Treatments in Poisoning (EXTRIP) workgroup systematically collected and rated the available evidence on the effect of and indications for ECTRs in cases of isoniazid poisoning. We conducted a systematic review of the literature, screened studies, extracted data on study characteristics, outcomes, and measurement characteristics, summarized findings, and formulated recommendations following published EXTRIP methods. Forty‐three studies (two animal studies, 34 patient reports or patient series, and seven pharmacokinetic studies) met inclusion criteria. Toxicokinetic or pharmacokinetic analysis was available for 60 patients, most treated with hemodialysis (n = 38). The workgroup assessed isoniazid as “Moderately Dialyzable” by hemodialysis for patients with normal kidney function (quality of evidence = C) and “Dialyzable” by hemodialysis for patients with impaired kidney function (quality of evidence = A). Clinical data for ECTR in isoniazid poisoning were available for 40 patients. Mortality of the cohort was 12.5%. Historical controls who received modern standard care including appropriately dosed pyridoxine generally had excellent outcomes. No benefit could be extrapolated from ECTR, although there was evidence of added costs and harms related to the double lumen catheter insertion, the extracorporeal procedure itself, and the extracorporeal removal of pyridoxine. The EXTRIP workgroup suggests against performing ECTR in addition to standard care (weak recommendation, very low quality of evidence) in patients with isoniazid poisoning. If standard dose pyridoxine cannot be administered, we suggest performing ECTR only in patients with seizures refractory to GABAA receptor agonists (weak recommendation, very low quality of evidence).
Breath figure‐derived porous fluorine‐containing poly(ether sulfone) membranes with low dielectric constant
Authors: Zhang Chongyang , Li Mengzhu , Sun Handong , Yue Xigui 
Published: March 2021

AbstractAs an important part of electronic packaging materials, low‐dielectric materials can ensure effective signal transmission between electronic components and have an impact on the performance of microprocessor chips. Herein, a porous poly(ether sulfone) membrane with low dielectric constant is fabricated via a breath figure method to meet requirements for high performance of new packaging materials. Perfluorononyl oxide side groups are introduced into the molecular structure of a block poly(ether sulfone) polymer by post‐grafting, and the pore‐making process and the dielectric properties of the materials are studied. The resulting multi‐block copolymers are found to have different electric and thermal properties depending on the molar ratio of perfluorononyl oxide side groups. Regular honeycomb pores can be formed with a polymer segment length of 8/16. Besides, the porous membranes with ordered pore structure on the surface possess low dielectric constant values ranging from 1.57 to 2.19 at 10 kHz. © 2021 Society of Industrial Chemistry.
Synthesis and formulation of self‐immolative PEG‐aryl azide block copolymers and click‐to‐release reactivity with trans‐cyclooctene
Authors: Dadhwal Sumit , Lee Arnold , Goswami Shailesh K. , Hook Sarah , Gamble Allan B. 
Published: March 2021

AbstractSelf‐immolative aryl azides can react with trans‐cyclooctenes (TCO), triphenylphosphines or hydrogen sulfide (H2S) to activate prodrugs, imaging probes and drug delivery systems. To date, the synthesis of polymers containing these aryl azide self‐immolative linkers and their reactivity with a strained alkene (i.e., in a bioorthogonal reaction) has not been explored. Also, due to the instability of aryl azides towards light and high temperatures, the polymerization methods compatible with aryl azides are limited. Through systematic investigation of the reversible addition‐fragmentation chain transfer (RAFT) and atom transfer radical polymerization (ATRP) methods, a self‐immolative PEG‐aryl azide block copolymer (PEG45‐b‐ABOC28 2) and a non‐responsive 4‐fluoroaryl block copolymer (PEG45‐b‐FBOC24 3) was prepared. ATRP provided the desired polymers in a highly controlled manner, whereas the RAFT conditions led to higher levels of aryl azide polymer degradation. The ATRP derived polymers 2 and 3 were formulated into nanoparticles of approximately 200 nm diameter, and particle triggering was demonstrated by the [3+2]‐cycloaddition reaction of TCO with PEG45‐b‐ABOC28 2 in solution (pure polymer) and as a formulated nanoparticle. Preliminary in vitro cell viability studies suggested that the stimuli‐responsive aryl azide polymers/nanoparticles are not cytotoxic up to 200 μg/ml concentrations.
Modeling of Accelerating Universe with Bulk Viscous Fluid in Bianchi V Space‐Time
Authors: Goswami G. K. , Yadav Anil Kumar , Mishra B. , Tripathy S. K. 
Published: March 2021

AbstractIn this paper, we have investigated a bulk viscous anisotropic Universe and constrained its model parameters with recent and Pantheon compilation data. Using cosmic chronometric technique, we estimate the present value of Hubble's constant as , and by bounding our derived model with recent data, Pantheon and joint and Pantheon data respectively. The present age of the Universe is specified as Gyrs. The model favours a transitioning Universe with the transition red‐shift as . We have reconstructed the jerk parameter using the observational data sets. From the analysis of the jerk parameter, it is observed that, our derived model shows a marginal departure from the concordance ΛCDM model.
Engineered expression of the invertebrate‐specific scorpion toxin AaHIT reduces adult longevity and female fecundity in the diamondback moth Plutella xylostella
Authors: Harvey‐Samuel Tim , Xu Xuejiao , Lovett Erica , Dafa'alla Tarig , Walker Adam , Norman Victoria C , Carter Ruth , Teal Joss , Akilan Luxziyah , Leftwich Philip T , Reitmayer Christine M , Siddiqui Hamid A , Alphey Luke 
Published: March 2021

AbstractBACKGROUNDPrevious genetic pest management (GPM) systems in diamondback moth (DBM) have relied on expressing lethal proteins (‘effectors’) that are ‘cell‐autonomous’, that is, they do not leave the cell in which they are expressed. To increase the flexibility of future GPM systems in DBM, we aimed to assess the use of a non‐cell‐autonomous, invertebrate‐specific, neurotoxic effector – the scorpion toxin AaHIT. This AaHIT effector was designed to be secreted by expressing cells, potentially leading to effects on distant cells, specifically neuromuscular junctions.RESULTSExpression of AaHIT caused a ‘shaking/quivering’ phenotype that could be repressed by provision of an antidote (tetracycline): a phenotype consistent with the AaHIT mode‐of‐action. This effect was more pronounced when AaHIT expression was driven by the Hr5/ie1 promoter (82.44% of males, 65.14% of females) rather than Op/ie2 (57.35% of males, 48.39% of females). Contrary to expectations, the shaking phenotype and observed fitness costs were limited to adults in which they caused severe reductions in mean longevity (−81%) and median female fecundity (−93%). Quantitative polymerase chain reactions of AaHIT expression patterns and analysis of piggyBac‐mediated transgene insertion sites suggest that restriction of the observed effects to the adult stages may be due to the influence of the local genomic environment on the tetO‐AaHIT transgene.CONCLUSIONWe demonstrated the feasibility of using non‐cell‐autonomous effectors within a GPM context for the first time in Lepidoptera, one of the most economically damaging orders of insects. These findings provide a framework for extending this system to other pest Lepidoptera and to other secreted effectors. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Nitrogen isotope analysis of aqueous ammonium and nitrate by membrane inlet isotope ratio mass spectrometry (MIRMS) at natural abundance levels
Authors: Dyckmans Jens , Eschenbach Wolfram , Langel Reinhard , Szwec Lars , Well Reinhard 
Published: March 2021

RationaleExisting methods for the measurement of the 15N/14N isotopic composition of ammonium and nitrate are either only suitable for labelled samples or require considerable sample preparation efforts (or both). Our goal was to modify an existing analytical approach to allow for natural abundance precision levels.MethodsPublished reaction protocols were used to convert ammonium into N2 by NaOBr and nitrate into N2O by TiCl3. A membrane inlet system was developed and coupled to an isotope ratio mass spectrometer to allow precise determination of the analytes.ResultsConcentrations of ≥35 μmol/L N for both ammonium or nitrate could be analysed for δ15N values with precisions of better than 0.9 mUr. While ammonium analyses exhibited a small concentration dependency and an offset of 2.7 mUr at high ammonium concentrations irrespective of the standard isotopic composition, nitrate analysis showed no offset but a blank contribution visible at very low concentrations.ConclusionsThe presented method is capable of fast measurement of δ15N values in ammonium and nitrate from aqueous samples with reasonable accuracy at natural abundance levels. It will thus facilitate the application of isotopic methods to studies of nitrogen cycling in ecosystems.
Continuous and simultaneous measurement of triple‐oxygen and hydrogen isotopes of liquid and vapor during evaporation experiments
Authors: Brady Matthew P. , Hodell David A. 
Published: March 2021

RationaleOxygen and hydrogen isotopes are important tools for studying the modern and past hydrological cycle. Previous evaporation experiments used episodic measurement of liquid and/or vapor or did not measure all isotopologues of water. Here, we describe an evaporation experimental system that allows all isotopologues of liquid and water vapor to be measured simultaneously and near‐continuously at high precision using cavity ring‐down laser spectroscopy (CRDS).MethodsEvaporating liquid is periodically sampled from a closed recirculating loop by a syringe pump that delivers a constant supply of water to the vaporizer, achieving a water vapor concentration of 20,000 ppmV H2O (±132, 1σ). Vapor is sampled directly from the evaporation chamber. Isotope ratios are measured simultaneously with a Picarro L2140‐i CRDS instrument.ResultsFor liquid measurements, Allan variance analysis indicates an optimum data collection window of 34 min for oxygen isotopes and 27 min for hydrogen isotopes. During these periods, the mean standard error is ±0.0081‰ for δ17O values, ±0.0081‰ for δ18O values, and ±0.019‰ for δ2H values. For the derived parameters 17O‐excess and d‐excess, the standard error of the mean is 5.8 per meg and 0.07‰, respectively. For the vapor phase a 12.5 min data window for all isotopologues results in a mean standard error of ±0.012‰ for δ17O values, ±0.011‰ for δ18O values, and ±0.023‰ for δ2H values. For the derived parameters, the standard error of the mean is 9.2 per meg for 17O‐excess and 0.099‰ for d‐excess. These measurements result in consistently narrow 95% confidence limits for the slopes of ln(δ17O + 1) vs ln(δ18O + 1) and ln(δ2H + 1) vs ln(δ18O + 1).ConclusionsThe experimental method permits measurement of fractionation of triple‐oxygen and hydrogen isotopes of evaporating water under varying controlled conditions at high precision. Application of this method will be useful for testing theoretical models of evaporation and conducting experiments to simulate evaporation and isotopic equilibration in natural systems.
Neural networks‐based sliding mode tracking control for the four wheel‐legged robot under uncertain interaction
Authors: Li Jing , Wu Qingbin , Wang Junzheng , Li Jiehao 
Published: March 2021

AbstractWhen considering the accuracy of tracking control, physical interaction such as structural uncertainties and external dynamics is the main challenge in actual engineering scenarios, especially for the complex robot system. In this article, a neural network‐based sliding mode tracking control scheme (SMCR) is presented for the developed four wheel‐legged robot (BIT‐NAZA) under the uncertain interaction. First, a non‐singular fast terminal function based on the kinematic model is proposed for path tracking, which improves the motion quality during the approach movement and the sliding mode movement. At the same time, it can reduce the influence of uncertain disturbances on the premise of ensuring the path tracking control accuracy via neural networks. Finally, some demonstrations using the autonomous platform of the BIT‐NAZA robot are employed to evaluate the robustness and effectiveness of the hybrid algorithm.