bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing cytochrome P450 enzyme diversity by identification of two distinct cyclodipeptide dimerases
Authors: Liu Jing , Xie Xiulan , Li Shu-Ming
Published: August 2020

Two P450 enzymes were characterised to catalyse distinct regio- and stereospecific dimerizations of cyclo-(l-Trp-l-Trp), differing from those previously reported in actinobacteria.
Role of specific distorted metal complexes in exciton self-trapping for hybrid metal halides
Authors: Gautier Romain , Clérac Rodolphe , Paris Michael , Massuyeau Florian
Published: August 2020

The photoemission by exciton self-trapping in low-dimensional hybrid metal halides is promoted for specific distortions of the metal environment. Selected crystal structures with such distortions enables the synthesis of efficient phosphors.
Photoinduced electron transfer from carbon nanotubes to fullerenes: C60versus C70
Authors: Yang Jia-Jia , Li Zi-Wen , Liu Xiang-Yang , Fang Wei-Hai , Cui Ganglong
Published: August 2020

Nonadiabatic dynamics simulations reveal interesting photoinduced electron transfer behaviors at interfaces of single-walled carbon nanotubes and fullerenes.
Excited state Born–Oppenheimer molecular dynamics through coupling between time dependent DFT and AMOEBA
Authors: Nottoli Michele , Mennucci Benedetta , Lipparini Filippo
Published: August 2020

We present the implementation of excited state Born–Oppenheimer molecular dynamics (BOMD) using a polarizable QM/MM approach based on time-dependent density functional theory (TDDFT) formulation and the AMOEBA force field.
tert-Butyl thiol and pyridine ligand co-protected 50-nuclei clusters: the effect of pyridines on Ag–SR bonds
Authors: Shen Yang-Lin , Jin Jun-Ling , Xie Yun-Peng , Lu Xing
Published: August 2020

The presence of pyridine ligands induces expansion of AgN–SR bond lengths compared to that of AgO–SR without pyridines, which has been proved to profoundly influence the construction of thiolate–silver(i) compounds.
Photochromic organic cage-encapsulated Au nanoparticles: light-regulated cavities for catalytic reduction of 4-nitrophenol
Authors: Fu Qiu-Ting , Yan Xiaodong , Zhang Xin-Yue , He Yue , Zhang Wen-Da , Liu Yong , Li Yunxing , Gu Zhi-Guo
Published: August 2020

Encapsulated Au nanoparticles in a diarylethene-based photochromic cage with adjustable particle sizes under UV and visible light exhibited different catalytic rates for the reduction of 4-nitrophenol.
Group 13-derived radicals from α-diimines via hydro- and carboalumination reactions
Authors: Bodach Alexander , Bamford Karlee L. , Longobardi Lauren E. , Felderhoff Michael , Stephan Douglas W.
Published: August 2020

Mechanochemically synthesized alanes and (hydrido-)alanes were reacted with α-diimines to form aluminium derived radicals.
Correction: An efficient metal-free pathway to vinyl thioesters with calcium carbide as the acetylene source
Authors: Rodygin Konstantin S. , Ananikov Valentine P.
Published: August 2020

Correction for ‘An efficient metal-free pathway to vinyl thioesters with calcium carbide as the acetylene source’ by Konstantin S. Rodygin et al., Green Chem., 2016, 18, 482–486. DOI: 10.1039/C5GC01552A.
Accurate and precise in situ U–Pb isotope dating of wolframite series minerals via LA-SF-ICP-MS
Authors: Yang Ming , Yang Yue-Heng , Wu Shi-Tou , Romer Rolf L. , Che Xu-Dong , Zhao Zi-Fu , Li Wen-Sheng , Yang Jin-Hui , Wu Fu-Yuan , Xie Lie-Wen , Huang Chao , Zhang Di , Zhang Yang
Published: August 2020

We present an analytical protocol for in situ U–Pb isotope dating of wolframite series minerals [(Fe,Mn)WO4], the main ore mineral for tungsten, by LA-SF-ICP-MS.
Enhanced flux of chemically induced hot electrons on a Pt nanowire/Si nanodiode during decomposition of hydrogen peroxide
Authors: Kim Heeyoung , Kim Ye Ji , Jung Yeon Sik , Park Jeong Young
Published: August 2020

To investigate the charge transfer at the metal–semiconductor interface, novel Pt nanowires/Si nanodiodes were fabricated. By detecting hot electrons during H2O2 decomposition, higher transmission probability for charge transport through metal–oxide interfaces was observed.
Rapid and selective detection of Hg(ii) in water using AuNP in situ-modified filter paper by a head-space solid phase extraction Zeeman atomic absorption spectroscopy method
Authors: Lei Yongqian , Zhang Fang , Guan Peng , Guo Pengran , Wang Guanhua
Published: August 2020

AuNPs modified filter paper as sensitive mercury sensor was applied in the head-space solid phase extraction (HS-SPE) of Hg(ii). With negative pressure sampling, it can achieve in situ sampling and detection rapidly in a complex environment.
Preparation of Cu2O nanocubes with different sizes and rough surfaces by a seed-mediated self-assembly process and their application as a non-enzymatic glucose sensor
Authors: Liu Wenbin , Chai Guochun , Zhang Jian , Wang Mingguang , Dai Yuxiang , Yang Qi
Published: August 2020

In this study, ultrafine and uniform cuprous oxide (Cu2O) nanocubes with different sizes and rough surfaces were prepared via a seed-mediated process.
The effect of physical morphology and the chemical state of Ru on the catalytic properties of Ru–carbon for cellulose hydrolytic hydrogenation
Authors: Zhang Gang , Chen Tong , Zhang Yi , Liu Tao , Wang Gongying
Published: August 2020

Ru–carbon catalysts with different physical morphologies and chemical states of Ru were prepared by different methods and used to catalyze the hydrolytic hydrogenation of cellulose at high temperatures.
Efficient photocatalytic hydrogen production by Mn0.05Cd0.95S nanoparticles anchored on cubic NiSe2
Authors: Liu Hua , Yan Teng , Jin Zhiliang , Ma Qingxiang
Published: August 2020

In the field of catalysis, three critical factors for evaluating catalyst activity include charge separation efficiency, photoabsorption, and surface activity sites.
Assembly of nanocube super-structures directed by surface and magnetic interactions
Authors: Stanković Igor , Lizardi Luis , García Carlos
Published: August 2020

We study the stabilisation of clusters and lattices of cuboidal particles with long-ranged magnetic dipolar and short-ranged surface interactions.
Nitrogen and iron codoped porous carbon polyhedra for effectively confining polysulfides and efficiently catalyzing their conversion in lithium–sulfur batteries
Authors: Yu Jingping , Khan Shahzad Ahmad , Zhao Dengke , Li Ligui , Wu Zexing , Niu Xiaojun , Chen Shaowei
Published: August 2020

Fe–N–C microporous carbon polyhedra with a trace amount of well-dispersed Fe atoms can effectively confine polysulfides and efficiently catalyze their conversion.
Up-regulation of CXCL8 expression is associated with a poor prognosis and enhances tumor cell malignant behaviors in liver cancer
Authors: Yang Song , Wang Han , Qin Chundi , Sun Hongmei , Han Yupeng
Published: August 2020

CXCL8, a member of CXC chemokines, was constitutively expressed in many types of human cancers, and its overexpression has been shown to play a critical role in promoting tumorigenesis. The purpose of the present study was to determine CXCL8 expression in a commercial human liver tissue microarray, and elucidate the effects and underlying mechanisms by which CXCL8 is involved in the malignant progression of human liver cancer. Our data showed that high level expression of CXCL8 in tissues with liver cancer was identified as compared with non-cancer tissues, and its up-regulation was closely associated with clinical stage and tumor infiltration. In vitro, exogenous CXCL8 at concentrations of 10, 20 or 40 ng/ml obviously stimulated the proliferation abilities of HepG2 cells. Coupled with this, 10, 20 or 40 ng/ml of exogenous CXCL8 also triggered a significant elevation in HepG2 cells migration. Additionally, overexpression of CXCL8 in HepG2 cells also resulted in increased cell proliferation and migration capacities. Finally, Western blotting analysis showed that overexpression of CXCL8 increased the expression of ERK, p-ERK and survivin, decreased the expression of caspase-3 and BAX at protein level.
Factors Influencing Initiation of Pharyngeal Swallow in Healthy Adults
Authors: Bhutada Ankita M. , Dey Rajarshi , Martin-Harris Bonnie , (Focht) Garand Kendrea L.
Published: August 2020

Purpose

The purpose of this study was to investigate factors influencing the initiation of pharyngeal swallow (IPS) in healthy, nondysphagic adults.

Method

A total of 195 healthy participants ranging in age from 21 to 89 years participated in a modified barium swallow study. IPS was quantified using the Modified Barium Swallow Impairment Profile standardized scoring system across nine swallowing tasks observed in the lateral viewing plane for each participant.

Results

Large variability for bolus head location at time of hyoid burst (IPS) was observed within this healthy cohort, ranging from the ramus of the mandible to the pyriform sinuses. Significant effects of bolus volume, viscosity, sex, and race were also observed.

Conclusion

Study findings indicate that IPS is variable in healthy adults and influenced by volume, viscosity, sex, and race. Thus, variability in IPS may be considered typical in otherwise nondysphagic adults. The clinical significance of high Modified Barium Swallow Impairment Profile IPS scores in dysphagic patients, therefore, must be considered within the context of other swallowing impairments.

Supplemental Material

https://doi.org/10.23641/asha.12735935
The Impact of Communication Modality on Voice Production
Authors: Tracy Lauren F. , Segina Roxanne K. , Cadiz Manuel Diaz , Stepp Cara E.
Published: August 2020

Purpose

Communicating remotely using audio and audiovisual technology is ubiquitous in modern work and social environments. Remote communication is increasing in medicine and in voice therapy delivery, and this evolution may have an impact on speakers' voices. This study sought to determine whether these communication modalities impact the voice production of typical speakers.

Method

The speech acoustics of 12 participants with healthy voices were recorded as they held standardized conversations with a single investigator using three communication modalities: in-person, remote-audio, and remote-audiovisual. Participants rated their vocal effort on a 100-mm visual analog scale.

Results

Compared to in-person communication, self-ratings of vocal effort were statistically significantly increased for remote-audiovisual communication; vocal effort during remote-audio and in-person communication were not significantly different. In comparison to in-person communication, vocal intensity and smoothed cepstral peak prominence (CPPS) were statistically significantly higher during remote-audio and remote-audiovisual communication. Effect sizes for CPPS changes were larger than for sound pressure level (SPL), and changes in CPPS and SPL between in-person and remote-audiovisual communication were not significantly correlated.

Conclusions

Vocal effort and SPL were increased when using remote-audio and remote-audiovisual communication in comparison to in-person communication. Voice quality was also impacted by technology use, with changes in CPPS that were consistent with, but not fully explained by, increases in SPL. This may impact the telepractice delivery of voice therapy, and further investigation is warranted.
Optimal frequency combination estimation for accurate ultrasound non‐destructive testing
Authors: Kumar A. , Shakya S. , Goswami M.
Published: August 2020

A non‐destructive testing system requires multiple system configuration parameters during the operation process. For a given transducer, scanning frequency and number of measurements for averaging are just among those parameters. This work tests the central limit theorem to optimally set these parameters. The authors have designed a compact ultrasound computer tomography scanner from scratch just to test this criterion. It is shown that optimal frequency value changes with respect to the scanning angle for an object with a heterogeneous inner profile. The proposed criterion helps to estimate the multi‐spectral combination before the recovery stage minimum error. Possible industrial applications of such a system are 2D/3D multiphase flow profile recovery or crack detection in the composite matter, non‐invasively.
Estimating magnetic field strength in a porous fin from a surface temperature response
Authors: Das R. , Kundu B.
Published: August 2020

This Letter demonstrates a non‐destructive prediction methodology for determining the necessary magnetic field to be imposed in a porous fin satisfying a particular heat generation occurring within an electronic device. For the first time, all possible kinds of heat transfer have been incorporated here, which were otherwise ignored in other published studies of a similar kind. Just observing the surface thermal response, golden section search (GSS) solver, in conjunction with a forward numerical scheme, has been used in this work to determine the strength of the magnetic field. Estimations are done for various levels of additive white Gaussian noise and satisfactory reconstructions are noted for noise level even up to 12%. The numerical method has been convincingly validated with other schemes of the published literature. Sensitivity analysis reveals that the temperature distribution is per se a strong function of the fin porosity and governed by a mutual trade‐off between the heat generation rate and the imposed magnetic field. The results obtained from the present analysis using GSS are proposed to offer assistance to design efficient porous fin based heat transfer surfaces for providing safety and better cooling in addition to a considerable weight reduction of the system.
Quantitative short‐term voltage stability analysis of power systems integrated with DFIG‐based wind farms
Authors: Qin Boyu , Li Hengyi , Zhang Xuemin , Ding Tao , Ma Ke , Mei Shengwei
Published: August 2020

With the growing penetration of doubly‐fed induction generator (DFIG)‐based wind farms (WFs) in power systems, short‐term voltage stability problem has become more prominent. This study proposes a new approach for post‐fault short‐term voltage stability analysis by establishing a quantitative relationship between the system states/outputs and external disturbances. The concept of the integral‐integral estimate, which is equivalent to input‐to‐state stability, was adopted to perform quantitative analysis at the subsystem level, and practical algorithms were developed to study the local input‐to‐state/output stability properties of subsystems. System‐level quantitative analysis was achieved through the proposed criterion considering the stability properties of subsystems and their connections. The proposed method reveals the dynamic responses of the system under external disturbances and quantifies the size of the external disturbance that the system can tolerate, thus facilitating the operation of the power system integrated with DFIG‐based WFs. The short‐term voltage stability of a test power system was analysed using the proposed quantitative stability analysis approach, and the results were verified through time‐domain simulations.
Stochastic frequency constrained unit commitment incorporating virtual inertial response from variable speed wind turbines
Authors: Malekpour Mostafa , Zare Mohsen , Azizipanah‐Abarghooee Rasoul , Terzija Vladimir
Published: August 2020

Increasing the penetration of converter‐interfaced renewable energy sources like variable speed wind turbines (VSWTs) leads to drastic challenges in keeping the system frequency stability due to system inertia decrement. In this study, a novel variable virtual inertia control strategy for VSWTs is developed which considers their mechanical restriction. It also makes the implication of VSWTs virtual inertial response straightforward to be analytically considered in the system frequency dynamic constraints like rate of change of frequency and frequency nadir. Furthermore, these constraints are formulated and incorporated into a chance frequency constrained unit commitment in order to minimize system operation cost while co‐optimizing both inertial response from VSWTs/conventional units and governor‐based primary frequency response. The proposed stochastic methods can curtail the load and wind power to satisfy a predefined level of operation risk which can coordinate the unit commitment problem with wind turbines. The comparison analysis on a 10 units standard test system and 4 case studies illustrates that increasing the penetration level of VSWTs from 17% to 36% can provide important savings up to 22.5% while the frequency constraints are also met by VSWTs virtual inertia provision. This helps increasing the penetration of renewables from the view point of frequency stability.
Carbon monoxide formation and cooling in supernovae
Authors: Liljegren S. , Jerkstrand A. , Grumer J.
Published: August 2020

Context. The inclusion of molecular physics is an important piece that tends to be missing from the puzzle when modeling the spectra of supernovae (SNe). Molecules have both a direct impact on the spectra, particularly in the infrared, and an indirect one as a result of their influence on certain physical conditions, such as temperature.

Aims. In this paper, we aim to investigate molecular formation and non-local thermodynamic equilibrium (NLTE) cooling, with a particular focus on CO, the most commonly detected molecule in supernovae. We also aim to determine the dependency of supernova chemistry on physical parameters and the relative sensitivity to rate uncertainties.

Methods. We implemented a chemical kinetic description of the destruction and formation of molecules into the SN spectral synthesis code SUMO. In addition, selected molecules were coupled into the full NLTE level population framework and, thus, we incorporated molecular NLTE cooling into the temperature equation. We produced a test model of the CO formation in SN 1987A between 150 and 600 days and investigated the sensitivity of the resulting molecular masses to the input parameters.

Results. We find that there is a close inter-dependency between the thermal evolution and the amount of CO formed, mainly through an important temperature-sensitive CO destruction process with O+. After a few hundred days, CO completely dominates the cooling of the oxygen-carbon zone of the supernova which, therefore, contributes little optical emission. The uncertainty of the calculated CO mass scales approximately linearly with the typical uncertainty factor for individual rates. We demonstrate how molecular masses can potentially be used to constrain various physical parameters of the supernova.
Is NGC 300 a pure exponential disk galaxy?
Authors: Jang In Sung , de Jong Roelof S. , Minchev Ivan , Bell Eric F. , Monachesi Antonela , Holwerda Benne W. , Bailin Jeremy , Smercina Adam , D’Souza Richard
Published: August 2020

NGC 300 is a low-mass disk galaxy in the Sculptor group. In the literature, it has been identified as a pure exponential disk galaxy, as its luminosity profile can be well fit with a single exponential law over many disk scale lengths (Type I). We investigate the stellar luminosity distribution of NGC 300 using Hubble Space Telescope archive data, reaching farther and deeper than any other previous studies. Color-magnitude diagrams show a significant population of old red giant branch (RGB) stars in all fields out to R ∼ 19 kpc (32′), as well as younger populations in the inner regions. We construct the density profiles of the young, intermediate-aged, and old stellar populations, and find two clear breaks in the density profiles of the old RGB and intermediate-aged stars: one down bending (Type II) at R ∼ 5.9 kpc, and another up bending (Type III) at R ∼ 8.3 kpc. Moreover, the old RGB stars exhibit a negative radial color gradient with an upward bend at R ∼ 8 kpc, beyond which the stellar populations are uniformly old (>7 Gyr) and metal poor ([Fe/H] = −1.6−0.4+0.2 dex). The outer stellar component at R ⪆ 8 kpc is therefore well separated from the inner disk in terms of stellar density and stellar population. While our results cast doubt on the currently established wisdom that NGC 300 is a pure exponential disk galaxy, a more detailed survey should be carried out to identify the outskirts as either a disk or a stellar halo.
Imagerie LIBS : aux portes de la clinique
Authors: Motto-Ros Vincent , Leprince Marine , Duponchel Ludovic , Sancey Lucie , Bonneterre Vincent , Dujardin Christophe , Pelascini Frédéric , Busser Benoit
Published: August 2020

L’étude de la dérégulation des métaux au sein des tissus biologiques intéresse de plus en plus le monde médical car une répartition anormale des métaux est une information importante qui peut contribuer au diagnostic clinique, et orienter le choix du traitement pour de nombreuses pathologies. En tant que méthode d’analyse élémentaire « tout optique », l’imagerie LIBS (laser-induced breakdown spectroscopy) est un candidat idéal pour étudier la composition élémentaire des tissus humains.
Therapie des SLE 2020: aktueller Stand nach den EULAR-Empfehlungen
2019
Authors: Mucke Johanna , Fischer-Betz Rebecca
Published: August 2020

Die Veröffentlichung der neuen ACR/EULAR Klassifikationskriterien
für den systemischen Lupus erythematodes (SLE) und die Überarbeitung der
EULAR-Empfehlungen zum Management des SLE im vergangenen Jahr beinhalten viele wichtige
Neuerungen, die die Klassifikation und Versorgung von Lupus-Patienten verändern
werden. Dies bezieht sich sowohl auf generelle Grundprinzipien der Versorgung sowie auf
konkrete Therapieempfehlungen. So kann ein SLE erst als solcher klassifiziert werden, wenn
antinukleäre Antikörper (ANA) unabhängig von Titer-Höhe
und Fluoreszenzmuster nachgewiesen werden können. Sind ANA nachgewiesen, erhalten
Lupus-spezifische Symptome und serologische Auffälligkeiten einen Punktwert. Ab
einem Wert von 10 kann ein SLE-Patient als solcher klassifiziert werden. Im Hinblick auf
die Versorgung von SLE-Patienten sollte jede Therapie ganz im Sinne eines treat-to-target
Ansatzes mit dem Ziel der Remission verfolgt werden. Dies dient der Sicherung des
Langzeitüberlebens, der Reduktion von Schaden sowie der Verbesserung von
Lebensqualität. Erreicht werden diese Ziele durch konsequente Therapie und
regelmäßige Evaluation der Krankheitsaktivität. So sollen alle
Patienten bei Abwesenheit von Kontraindikationen Antimalariamittel erhalten. Bei
unzureichendem Ansprechen werden Steroidpulse über wenige Tage sowie der
frühzeitige Einsatz von Immunsuppressiva (IM) empfohlen. Die einzelnen IM und ihre
jeweiligen Indikationen sind im Text aufgeführt. Mit dem Einbezug von Biologika,
insbesondere Belimumab und Rituximab, haben außerdem nun ganz neue Substanzklassen
Einzug in die Empfehlungen gefunden.
Efficacy and Safety of Stereotactic Radiotherapy in Cushing’s Disease: A Single Center Experience
Authors: Apaydin Tugce , Ozkaya Hande Mefkure , Durmaz Sebnem Memis , Meral Rasim , Kadioglu Pinar
Published: August 2020

Objective To determine the efficacy and safety of stereotactic radiotherapy (RT) in patients with Cushing’s disease (CD).

Methods The study included 38 patients [31 patients who
received gamma knife radiosurgery (GKS) and 7 patients who received
cyberknife hypofractionated RT (HFRT)] with CD. Hormonal remission was
considered if the patient had suppressed cortisol levels after low dose
dexamethasone, normal 24-hour urinary free cortisol (UFC), and lack or
regression of clinical features.

Results Biochemical control after RT was observed in
52.6% of the patients with CD and median time to hormonal remission
was 15 months. Tumor size control was obtained in all of the patients. There
was no significant relationship between remission rate and laboratory,
radiological and pathological variables except for preoperative UFC.
Remission rate was higher in patients with lower preoperative UFC. Time to
remission increased in parallel to postoperative cortisol and 1mg DST level.
Although medical therapy before RT did not affect the rate of- and time to
remission, medical therapy after RT prolonged the time to hormonal
remission.

Conclusion In this current single center experience,
postoperative cortisol and 1mg DST levels were found as the determinants of
time to remission. Although medical therapy before RT did not affect the
rate of- and time to remission, medical therapy after RT prolonged the time
to biochemical control . This latter finding might suggest a radioprotective
effect of cortisol lowering medication use on peri-RT period.
Comparison of endoscopic ultrasound-guided fine-needle biopsy versus fine-needle aspiration for genomic profiling and DNA yield in pancreatic cancer: a randomized crossover trial
Authors: Kandel Pujan , Nassar Aziza , Gomez Victoria , Raimondo Massimo , Woodward Timothy A. , Crook Julia E. , Fares Natalie S. , Wallace Michael B.
Published: August 2020

Background National guidelines recommend genomic profiling of tumor tissue to guide precision therapy. We compared the specimen adequacy for genomic profiling and yield of DNA between endoscopic ultrasound (EUS)-guided fine-needle biopsy (FNB) and EUS-guided fine-needle aspiration (FNA).

Methods In our tandem, randomized controlled trial, consecutive patients undergoing EUS for evaluation of pancreatic masses underwent both conventional EUS-FNA with a 25-gauge needle and paired EUS-FNB (19 or 22-gauge needle), with the order randomized (EUS-FNA first followed by EUS-FNB, or vice versa). A minimum of one pass with each needle was obtained for histology. Second and third passes were performed to collect DNA. Specimens were evaluated by a cytopathologist blinded to the needle type. Specimen adequacy for genomic profiling was calculated based on FoundationOne clinical diagnostic (CDx) adequacy requirements. We compared the adequacy for genomic profiling DNA (quantity) and histology yields with both needles.

Results Analysis included 50 patients (25 men; mean age 68 [standard deviation (SD) 13] years), with a mean lesion size of 38 (SD 17) mm; 37 lesions (74 %) were pancreatic ductal adenocarcinoma (PDAC). The mean DNA concentrations in PDAC by FNB and FNA needles were 5.930 (SD 0.881) µg/mL vs. 3.365 (SD 0.788) µg/mL, respectively (P = 0.01). The median standardized histology score per pass with EUS-FNB was 5 (sufficient for histology) and for EUS-FNA was 2 (enough for cytology). Specimen adequacy for genomic profiling and yield of DNA was significantly higher with FNB than with FNA needles.

Conclusions In this study, adequacy for genomic profiling, DNA, and histology yield were considerably superior using an EUS-FNB needle compared with an EUS-FNA needle.
Synthesis of l-Kynurenine and Homo-l-Kynurenine via an Aza-Fries Rearrangement
Authors: Vázquez Alfredo , Bonilla-Reyes Edgar , Sánchez-Carrillo Adrian
Published: August 2020

l-Kynurenine, a non-proteinogenic amino acid, is the primary metabolite of tryptophan via the kynurenine pathway. Kynurenine is involved in a variety of biological processes occurring in the human body, notably in the central nervous system. Thus, the study of this molecule offers multiple opportunities for drug discovery; however, an essential prelude for biological studies is to secure the supply of kynurenine and analogues thereof. A simple synthetic procedure for the efficient preparation of enantiomerically pure l-kynurenine from l-aspartic acid and its implementation to prepare homo-l-kynurenine from l-glutamic acid is presented. The approach relies on a photochemical aza-Fries rearrangement of the corresponding acyl-aniline as the fundamental transformation.
Liouville-type equations for the n-particle distribution functions of an open system
Authors: Delle Site Luigi , Klein Rupert
Published: August 2020

In this work, we derive a mathematical model for an open system that exchanges particles and momentum with a reservoir from their joint Hamiltonian dynamics. The complexity of this many-particle problem is addressed by introducing a countable set of n-particle phase space distribution functions just for the open subsystem, while accounting for the reservoir only in terms of statistical expectations. From the Liouville equation for the full system, we derive a set of coupled Liouville-type equations for the n-particle distributions by marginalization with respect to reservoir states. The resulting equation hierarchy describes the external momentum forcing of the open system by the reservoir across its boundaries, and it covers the effects of particle exchanges, which induce probability transfers between the n- and (n + 1)-particle distributions. Similarities and differences with the Bergmann–Lebowitz model of open systems [P. G. Bergmann and J. L. Lebowitz, Phys. Rev. 99, 578–587 (1955)] are discussed in the context of the implementation of these guiding principles in a computational scheme for molecular simulations.
Performance of the newly installed vertical neutron cameras for low neutron yield discharges in the Large Helical Device
Authors: Sangaroon S. , Ogawa K. , Isobe M. , Kobayashi M. I. , Fujiwara Y. , Kamio S. , Seki R. , Nuga H. , Yamaguchi H. , Osakabe M.
Published: August 2020

Two new vertical neutron cameras characterized by high detection efficiency were developed on the Large Helical Device in order to observe poloidal structures of helically trapped beam ions created by the perpendicularly injected positive-ion based neutral beam (P-NB) and are newly operated since 2018. In this work, the neutron fields at the vertical neutron cameras are investigated using the Monte Carlo N-particle transport code to evaluate the performance of its collimators. The results indicate that neutrons are attenuated by the heavy concrete and are well collimated through the collimator to detectors. Neutron spectra at the detector position show over 99% of uncollided 2.45 MeV neutrons. Time evolution of neutron emission profiles during the short pulse of P-NB injection is measured by the vertical neutron cameras. Peaks on the neutron emission profiles corresponding to the helically trapped beam ion are successfully obtained, as designed. The decrease in line integrated neutron flux at the peak positions after the P-NB stops is consistent with the behavior of the total neutron emission rate measured by the neutron flux monitor.
Microfluidic polyimide gas dynamic virtual nozzles for serial crystallography
Authors: Vakili Mohammad , Vasireddi Ramakrishna , Gwozdz Paul V. , Monteiro Diana C. F. , Heymann Michael , Blick Robert H. , Trebbin Martin
Published: August 2020

Free liquid jets are a common sample delivery method in serial femtosecond x-ray (SFX) crystallography. Gas dynamic virtual nozzles (GDVNs) use an outer gas stream to focus a liquid jet down to a few micrometers in diameter. Such nozzles can be fabricated through various methods (capillary grinding, soft lithography, digital light processing, and two-photon polymerization) and materials, such as glass, polydimethylsiloxane, and photosensitive polyacrylates. Here, we present a broadly accessible, rapid prototyping laser ablation approach to micromachine solvent-resistant and inert Kapton polyimide foils with highly reproducible geometric features that result in 3D flow-focused GDVNs suitable for crystallography experiments at synchrotrons and free-electron laser facilities.
Growth mechanism of
α
-Ga2O3 on a sapphire substrate by mist chemical vapor deposition using acetylacetonated gallium source solutions
Authors: Uno Kazuyuki , Ohta Marika , Tanaka Ichiro
Published: August 2020

α-Ga2O3 is a metastable phase of gallium oxide (Ga2O3) and is important for application in solar-blind region optoelectronic devices. High-quality α-Ga2O3 thin films can be grown by mist chemical vapor deposition (mist-CVD). We systematically investigate the growth mechanism of α-Ga2O3 by mist-CVD using acetylacetonated Ga source solutions. We propose a growth mechanism of α-Ga2O3 in mist-CVD in which acetylacetonate ligands anchor to surface hydroxyls and Ga–O bonds are formed by a ligand exchange mechanism. The origin of oxygen atoms and impurity concentration profiles in grown α-Ga2O3 thin films are examined by secondary ion mass spectroscopy.
Terahertz time-domain spectroscopy of two-dimensional plasmons in AlGaN/GaN heterostructures
Authors: Pashnev Daniil , Kaplas Tommi , Korotyeyev Vadym , Janonis Vytautas , Urbanowicz Andrzej , Jorudas Justinas , Kašalynas Irmantas
Published: August 2020

Two-dimensional plasmons were investigated by terahertz time domain spectroscopy observing experimentally the distinctive minima and inflection points in the transmission power amplitude and phase spectra, respectively. Gratings of different periods (600, 800, and 1000 nm) and filling factors (50 and 80%) were provided to the two-dimensional electron gas in AlGaN/GaN heterostructures in order to measure the plasmon dispersion and the coupling efficiency with THz radiation. Comparative analysis of experimental data revealed that the resonant plasmon features in the amplitude spectrum are related to those in the phase spectrum by a simple integral relation, paving the way for phase spectroscopy of the plasmon phenomena in fields of THz physics and engineering.
An accurate machine-learning calculator for optimization of Li-ion battery cathodes
Authors: Houchins Gregory , Viswanathan Venkatasubramanian
Published: August 2020

There is significant interest in improving the performance of batteries to increase electrification of transportation and aviation. Recently, performance improvements have been in large part due to changes in the composition of the cathode material family, LiNixMnyCo(1−x−y)O2 (e.g., 111–622–811). Despite the importance of these materials and tremendous progress with density functional theory (DFT) calculations in understanding basic design principles, it is computationally prohibitively expensive to make this problem tractable. Specifically, predicting the open circuit voltage for any cathode material in this family requires evaluation of stability in a quaternary phase space. In this work, we develop machine-learning potentials using fingerprinting based on atom-centered symmetry functions, used with a neural network model, trained on DFT calculations with a prediction accuracy of 3.7 meV/atom and 0.13 eV/Å for energy and force, respectively. We perform hyperparameter optimization of the fingerprinting parameters using Bayesian optimization through the Dragonfly package. Using this ML calculator, we first test its performance in predicting thermodynamic properties within the Debye–Grüneisen model and find good agreement for most thermodynamic properties, including the Gibbs free energy and entropy. Then, we use this to calculate the Li-vacancy ordering as a function of Li composition to simulate the process of discharging/charging of the cathode using grand canonical Monte Carlo simulations. The predicted voltage profiles are in good agreement with the experimental ones and provide an approach to rapidly perform design optimization in this phase space. This study serves as a proof-point of machine-learned DFT surrogates to enable battery materials optimization.
Transition metal dichalcogenides thyristor realized by solid ionic conductor gate induced doping
Authors: Wang Guangyao , Deng Wenjie , Chen Xiaoqing , Wang Peng , Xiao Yu , Li Jingfeng , Chu Feihong , Liu Beiyun , Chen Yongfeng , Lu Yue , Sui Manling , Liu Zhihong , Diao Xungang , Yan Hui , Zhang Yongzhe
Published: August 2020

Transition metal dichalcogenides (TMDCs) are promising for future electronic and optoelectronic applications, such as field effect transistors (FETs), for their high carrier mobility with a thin layer, wide bandgap, and organic-like flexibility. However, background doping and unipolar electrical characteristics are commonly observed in TMDCs and their based FETs due to the naturally inevitable vacancy defects, which limit their application in electronics and optoelectronics systems. Here, taking MoS2 as an example, in a TMDC FET, ambipolar properties were achieved at room temperature by introducing an amorphous solid ionic conductor lithium tantalate (LiTaO3) as the gate dielectric, which could guarantee the modulation of the Fermi level in the MoS2 channel by the gate electric field. Based on the modulation mechanisms by the solid ionic conductor-gated electric field for the transformation of conduction mode, the three-terminal device exhibits a gate-controlled rectifying, that is, thyristor performance with a high rectification ratio over 300 obtained at a low gate voltage of 2 V. The present results show the great potential of TMDCs in future logic and other electronic device applications.
Current-induced bulk magnetization of a chiral crystal CrNb3S6
Authors: Nabei Yoji , Hirobe Daichi , Shimamoto Yusuke , Shiota Kohei , Inui Akito , Kousaka Yusuke , Togawa Yoshihiko , Yamamoto Hiroshi M.
Published: August 2020

Current-induced magnetization has been investigated in a monoaxial chiral crystal CrNb3S6 by means of superconducting quantum interference device magnetometry. We found that bulk magnetization was generated by applying electric current along the principal axis of the monoaxial chiral crystal and that the magnetization changed linearly with the current. Directly detecting such magnetization enables one to estimate the number of spin-polarized electrons. Using this number, we evaluated the spin polarization rate within the framework of Boltzmann's equation. We also observed that the current-induced magnetization increased in the vicinity of the phase boundary between paramagnetic and forced ferromagnetic phases, which could be attributed to the enhancement of spin fluctuation. We discuss these observations based on a chirality-induced spin selectivity effect enhanced by exchange interactions.
Identification of excess charge carriers in InP-based quantum-dot light-emitting diodes
Authors: Su Qiang , Zhang Heng , Chen Shuming
Published: August 2020

InP-based quantum-dot light-emitting diodes (QLEDs) have recently attracted a lot of attention from academia and industry owing to their environment-friendly characteristics and have been hotly investigated as promising alternatives to toxic CdSe-based QLEDs. Although the performances of InP-QLEDs have been rapidly improved in recent years, the device mechanisms are not completely clear and there are still debates in the community regarding the details of excess charge carriers, which are expected to affect the charge balance and the efficiency of the devices. In this work, by studying the influence of charge injection on the efficiency and the charge carrier dynamics, we identify that holes are over-injected in InP-QLEDs, which is different from that in CdSe-QLEDs. By enhancing the injection of electrons and/or blocking the injection of holes, the population of excess holes is reduced, consequently enabling red and green InP-QLEDs with high external quantum efficiencies of 10.78% and 7.56%, respectively. Our work provides a practical way to identify the type of excess carrier and can serve as a useful guide for the optimization of charge balance in InP-QLEDs.
Predictive modeling of disease propagation in a mobile, connected community using cellular automata
Authors: Tiwari Ishant , Sarin Pradeep , Parmananda P.
Published: August 2020

We present numerical results obtained from the modeling of a stochastic, highly connected, and mobile community. The spread of attributes like health and disease among the community members is simulated using cellular automata on a planar two-dimensional surface. With remarkably few assumptions, we are able to predict the future course of propagation of such a disease as a function of time and the fine-tuning of parameters related to interactions among the automata.
A survey and critical review of wombat diets in captivity
Authors: Stannard Hayley J. , Purdy Katherine , Old Julie M.
Published: August 2020

Much of the literature on wombat diet is concerned only with the broad categories of consumed matter, and there is little about their specific nutritional requirements despite diet playing a major role in health. This study gathered information by surveying zoological parks and wildlife carers about current feeding regime, diet and the prevalence of nutritional or dental disorders of wombats held in captivity, with the aim of improving the diets of captive wombats, thus their health and welfare outcomes. Data on the composition, variation and basis of diets for 31 bare-nosed or common wombats (Vombatus ursinus) and 19 southern hairy-nosed wombats (Lasiorhinus latifrons) were gathered from 13 facilities. The nutritional values of diets fed to wombats in captivity were calculated and compared with known dietary requirements for bare-nosed wombats. Results demonstrate that the current diet of wombats held in captivity often consists of a high portion of fruits, vegetables and livestock feed, with the fruit and vegetable portions providing higher levels of simple carbohydrates and starch compared with natural grass diets. Generally, the facilities are providing diets that are exceeding reported maintenance energy and nitrogen requirements. Due to a lack of details provided regarding quantity and species of grasses fed, we could not provide an accurate ration calculation for the proportion of grasses in the diets. Some of the health concerns noted included insufficient weight gain, endoparasites, malocclusion and insufficient tooth wear. Further research is required to assess the requirements of reproductive, lactating and juvenile wombats; however, it is clear that wombats in captivity need to be fed larger volumes and varieties of grasses, forbs and sedges than they are currently being fed to maintain good health.
Proenkephalin+regulatory T cells expanded by ultraviolet B exposure maintain skin homeostasis with a healing function
Authors: Shime Hiroaki , Odanaka Mizuyu , Tsuiji Makoto , Matoba Takuma , Imai Masaki , Yasumizu Yoshiaki , Uraki Ryuta , Minohara Kiyoshi , Watanabe Maiko , Bonito Anthony John , Fukuyama Hidehiro , Ohkura Naganari , Sakaguchi Shimon , Morita Akimichi , Yamazaki Sayuri
Published: August 2020

Significance

Regulatory T (Treg) cells, expressing CD25 and Foxp3, constitute about 5 to 10% of peripheral CD4+T cells and maintain immunological self-tolerance through the suppression of various immune responses. Here we found that skin Treg cells expanded by UVB exposure possess a unique TCR repertoire and a healing function. UVB-expanded skin Treg (UVB-skin Treg) cells expressed proenkephalin (PENK), an endogenous opioid precursor, and amphiregulin (AREG), the epidermal growth factor receptor ligand. The Treg-derived PENK and AREG promoted keratinocyte outgrowth in a skin explant assay. Moreover, UVB-expanded skin Treg cells played a key role in promoting wound healing in vivo. Our results provide a new implication in developing a therapy using PENK+UVB-skin Treg cells.
Genesis and spread of multiple reassortants during the 2016/2017 H5 avian influenza epidemic in Eurasia
Authors: Lycett Samantha J. , Pohlmann Anne , Staubach Christoph , Caliendo Valentina , Woolhouse Mark , Beer Martin , Kuiken Thijs ,   Global Consortium for H5N8 and Related Influenza Viruses, Lycett Samantha J. , Pohlmann Anne , Staubach Christoph , Caliendo Valentina , van Borm Steven , Breed Andrew , Briand Francois-Xavier , Brown Ian , Dán Ádám , DeLiberto Thomas , von Dobschuetz Sophie , Fouchier Ron , Gilbert Marius , Hill Sarah , Hjulsager Charlotte Kristiane , Ip Hon , Koopmans Marion , Larsen Lars Erik , Lee Dong-Hun , Naguib Mahmoud Mohamed , Monne Isabella , Pybus Oliver , Ramey Andrew , Savic Vladimir , Sharshov Kirill , Shestopalov Alexander , Song Chang-Seon , Steensels Mieke , Swayne David , Świętoń Edyta , Wan XiuFeng , Zohari Siamak , Woolhouse Mark , Beer Martin , Kuiken Thijs
Published: August 2020

Significance

In 2016/2017, highly pathogenic avian influenza (HPAI) virus of the subtype H5 spilled over into wild birds and caused the largest known HPAI epidemic in Europe, affecting poultry and wild birds. During its spread, the virus frequently exchanged genetic material (reassortment) with cocirculating low-pathogenic avian influenza viruses. To determine where and when these reassortments occurred, we analyzed Eurasian avian influenza viruses and identified a large set of H5 HPAI reassortants. We found that new genetic material likely came from wild birds across their migratory range and from domestic ducks not only in China, but also in central Europe. This knowledge is important to understand how the virus could adapt to wild birds and become established in wild bird populations.
A membrane-depolarizing toxin substrate of the
Staphylococcus aureus
type VII secretion system mediates intraspecies competition
Authors: Ulhuq Fatima R. , Gomes Margarida C. , Duggan Gina M. , Guo Manman , Mendonca Chriselle , Buchanan Grant , Chalmers James D. , Cao Zhenping , Kneuper Holger , Murdoch Sarah , Thomson Sarah , Strahl Henrik , Trost Matthias , Mostowy Serge , Palmer Tracy
Published: August 2020

Significance

Staphylococcus aureus
, a human commensal organism that asymptomatically colonizes the nares, is capable of causing serious disease following breach of the mucosal barrier.
S. aureus
strains encode a type VII secretion system that is required for virulence in mouse infection models, and some strains also secrete a nuclease toxin by this route that has antibacterial activity. Here we identify TspA, widely found in Staphylococci and other pathogenic bacteria, as a type VII substrate. We show that TspA has membrane-depolarizing activity and that
S. aureus
uses TspA to inhibit the growth of a bacterial competitor in vivo.
Nanodiamond ensemble-based temperature measurement in living cells and its limitations
Authors: An Haechan , Yin Zechuan , Mitchell Chandler , Semnani Abbas , Hajrasouliha Amir R , Hosseini Mahdi
Published: August 2020

We consider incubation of nanodiamonds (NDs) in endothelial culture cells as a way to measure their temperature with sub-Kelvin sensitivity. We discuss limitations of ND temperature sensing in living cells, how to overcome the limitations and potential applications of such measurements.
A fast and robust algorithm for general defocusing particle tracking
Authors: Rossi Massimiliano , Barnkob Rune
Published: August 2020

The increasing use of microfluidics in industrial, biomedical, and clinical applications requires a more and more precise control of the microfluidic flows and suspended particles or cells. This leads to higher demands in three-dimensional and automated particle tracking methods, e.g. for use in feedback-control systems. General defocusing particle tracking (GDPT) is a 3D particle tracking method based on defocused particle images which is easy to use and requires standard laboratory equipment. In this work, we describe in detail a fast and robust algorithm for performing GDPT, which is suitable for automatized and real-time applications. Its key feature is a fast, segmentation-free approach to identify particles and estimate their 3D position. This detection step is followed by a refinement and iteration step to improve accuracy and identification of overlapping particles. We show that the algorithm is versatile and can be applied to different types of images (darkfield and brightfield). We use synthetic image sets of varying particle concentration to evaluate the performance of the algorithm in terms of detected depth coordinate uncertainty, particle detection rate, and processing time. The algorithm is applied and validated on experimental images showing that it is robust towards background or illumination fluctuations. Finally, to test the algorithm on real-time applications, we use synthetic images to set up a simulation framework with experimentally-relevant parameters and where the true particle positions are known.