bluuebunny/crossref_metadata_2025 huggingface dataset:
The Bragg reflection characteristics of the fibre grating formed by chirped ultr ashort laser pulses
Authors: Wang Huai-Sheng  , Sun Da-Rui  , Zhang Zhi-Gang  , Chai Lu  , Wang Qing-Yue  ,   天津大学精仪学院超快激光实验室，光电信息技术科学教育部重点实验室，天津  300072
Published: December 2020

Under the illumination of 800 nm femtosecond laser pulse, two-photon absorption phenomenon can occur in the photosensitive glass As2S3.　 When a chirped femtosecond laser pulse meets with another femtosecond laser pulse in an As2S3 fibre, the interference pattern can be recorded permanently as a chirped grating. In this paper, the relation between the structure of the chirped fibre grating and the parameters of the incident femtosecond pulse is described. Numerical calculations show that the chirped fibre grating has a broad Bragg reflection spectrum.
Mechanism of radiation effects in floating gate ROMs
Authors: He Chao-Hui  , Geng Bin  , Yang Hai-Liang  , Chen Xiao-Hua  , Li Guo-Zheng  , Wang Yan-Ping  ,   西北核技术研究所,西安  710613
Published: December 2020

Mechanism of irradiation effects is analyzed for floating gate read only memorie s (ROMs). Phenomena in experiments are reasonably explained. It is proposed that failures in devices result from oxide trapped charge and interface trapped char ge generated by radiation in memory cells and peripheral circuitry. The neutron, proton and 60Co γ irradiation effects in FLASH ROM and EEPROM a re total dose effects.
Characterization of the nonlinearly excited magnon pair
Authors: Shi Qing-Fan  , Yan Xue-Qun  ,   北京理工大学应用物理系,北京  100081；中国科学院物理研究所,北京  100080
Published: December 2020

The Hamilton's equations of motion were derived by analyzing the process of excitation for magnon pair in magneto-ordered medium placed in a microwave oscillator. The result showed that the magnon pair couples with the microwave resonator with nonlinearly oscillatory characterization.
Electrical properties of (Bi05Na05)TiO3 ceramic prepared by sol-gel method
Authors: Zhao Ming-Lei  , Wang Chun-Lei  , Zhong Wei-Lie  , Wang Jin-Feng  , Chen Hong-Cun  ,   山东大学物理系,山东大学晶体材料国家重点实验室,济南  250100
Published: December 2020

Bismuth sodium titanate Bi05Na05TiO3 ceramic with about 96% of theoretical density was prepared by sol-gel processing. The saturate P-E hysteresis loop can be obtained under a 100kV/cm AC electric field for the sol-gel processed Bi05Na05TiO3 ceramic and the remanent polarization Pr and coercive field Ec are 32μC/cm2 and 61kV/cm respectively. Moreover, from the piezoelectric measurements, this material fabricated by sol-gel processing was found to have increased piezoelectric constant d33=102×10-12C/N and electromechanical coupling factor kt=58%. Therefore, sol-gel method is a potential fabrication technique for this lead-free piezoelectric ceramic.
The contribution of Fe atom to the magnetic moment of quaternary Heusler alloy N iMnFeGa
Authors: Qian Zheng-Nan  , Sui Yu  , Liu Yu-Qiang  , Liu Zhu-Hong  , Liu Guo-Dong  , Zhang Ming  , Cui Yu-Ting  , Chen Jing-Lan  , Wu Guang-Heng  ,   (1)哈尔滨工业大学凝聚态科技中心，哈尔滨  150001; (2)中国科学院物理研究所磁学国家重点实验室，北京  100080
Published: December 2020

We have synthesized the pseudo-quaternary Heusler alloy Ni50Mn25 -xFe xGa25(x=0—25) by arc-melting and melt-spinning techniques .The structure ,magnetic properties,and martensitic phase transformation were investigated.The thermoelastic martensitic transformation characteristics and x-ray diffraction c onfirmed the high chemical ordering L21 structure of our samples in t he whole doping range.The dopant of iron decreases the martensitic transformation tempera ture and increases the Curie temperature for the doping level of x＜17.The ferro magnetic contribution of Fe atoms in Ni50.5Mn25-xFexGa24.5 h as been investigated in detail by precisely measuring the magnetization at 4K.It has been found that Fe atoms were indeed in Mn positions and contributed a loca lized moment up to 2.55—3.55μB.
A time-dependent damped harmonic oscillator with a force quadratic in velocity
Authors: Huang Bo-Wen  ,   首都师范大学物理系，北京  100037
Published: December 2020

A time-dependent damped harmonic oscillator with a nonconservative force quadratic in velocity (THOFQV) is described by an appropriate Lagrangian,and hence the general solution of THOFQV can be found.The solution of the Schrdinger equation for the system,such as the eigenfunctions and eigenvalues,is derived by utilizing these invariant operators.
A statistical property to recover coarsely initial conditions from coupled map lattices
Authors: Zeng Yi-Cheng  , Tong Qin-Ye  ,   (1)浙江大学生物医学工程系，杭州  310027; (2)浙江大学生物医学工程系，杭州  310027;湘潭大学材料与光电物理学院，湘潭  411105
Published: December 2020

To recover the initial signals in coupled map lattices (CMLs) is a key work when CMLs are applied to signal processing.In this paper,a method to roughly recover the initial signal is proposed.Numerical simulations show that the mean of recovered initial conditions from the coupled map lattices is equal to that of the given(real value),and the variance of recovered initial conditions is less than that of the given.For explaining these properties,when a Logistic map is coupled to others,it is taben as undergoing a transformation.Meanwhile,some interesting phenomena are found to sort two sequences obtained under Logistic mapping with different parameters.The results in this paper is heuristic for CMLs study and coupled nonlinear measurement etc.
The squeezing of angular momentum and its evolutions in atomic Schrdinger cat states
Authors: Dong Chuan-Hua  ,   上海大学物理系,上海  200436
Published: December 2020

The atomic coherent states will evolve to the atomic Schrdinger cat states at some special times in a low-Q acvity. The fluctuations and higher-order fluctuations of angular momentum in these atomic Schrdinger cat states are discussed. According to the uncertainty principle, the squeezing and higher-order squeezing for atomic angular momentum are investigated. It shows that the atomic Schrdinger cat states can be squeezed to second-and sixth-order, but cannot be squeezed to fourth-order. The properties of squeezing of atomic Schrdinger cat states formed by superposing infinite terms of atomic coherent states are identical with those of atomic coherent states.
Interference enhancement of two-photon absorption caused by a pair of coherent superposition levels in Na
Authors: Zhang Yan-Liang  , Jiang Li  , Niu Yue-Ping  , Sun Zhen-Rong  , Ding Liang-En  , Wang Zu-Geng  ,   (1)华东师范大学物理系,光谱学与波谱学教育部重点实验室,上海  200062; (2)陕西师范大学,物理学与信息技术学院,西安  710062
Published: December 2020

In the sodium dimer rhomb-type four-level system with a pair of coherent superposition levels, the interference enhancement of two-photon absorption caused by coherent superposition of the coupling levels is experimentally observed. The calculated results using density matrix equation are in good agreement with the experimental results.
The choke effect on a two-dimensional granular flow and the relation with its speed
Authors: Bao De-Song  , Zhang Xun-Sheng  , Xu Guang-Lei  , Pan Zheng-Quan  , Tang Xiao-Wei  , Lu Kun- Quan  ,   (1)浙江大学物理系，杭州  310027; (2)中国科学院物理研究所，北京  100080
Published: December 2020

The motion of granular wafers relative to its speed and the opening-size at choke point has been studied experimentally on a two-dimensional conveyer belt. The result shows that there is a critical speed vc when the opening-size d is fixed. The rate of flow Q increases linearly with the speed v, when v＜vc.The change of the Q-v curve occurs at the speed of vc.The critical speed vc is dependent on the opening-size d. The interaction between the granular wafers is changed when altering the speed or the opening-size at the choke point, and affects the motion of granular flow.
Average-bond-energy method in Schottky barrier height calculation
Authors: Li Shu-Ping  , Wang Ren-Zhi  ,   厦门大学物理系，厦门  361005
Published: December 2020

Ten barrier heights of metal-semiconductor contacts are calculated by taking the average-bond-energy as the reference level- The coincidence degree of the calculational values and the experimental values is as good as that of Tersoff's charge-neutrality point method in theoretical calculation of metal-semiconductor contacts- The calculational results are much better than that of Harrison's tight-binding method and Cardona's dielectric midgap energy method-
Effects of vapour on the stability of single-bubble sonoluminescence
Authors: Liu Hai-Jun  , An Yu  ,   清华大学物理系,北京  100084
Published: December 2020

We have derived a dynamical equation of shape instability for a spherical bubble，where water vapor evaporation and condensation at a sonoluminescencing bubble wall are considered- Using the derived equation and the mass diffusive equilibrium condition for the bubble vibration, we investigate the bubble instability on those controlled conditions of water temperature and corresponding acoustic frequency (for 14％ of argon concentration dissolved in water with the frequency of 206kHz at 217℃, for a 20kPa 1% argon in nitrogen bubble with the frequency of 319kHz at 0℃ and with the frequency of 338kHz at 20℃)- Comparing the calculated results with the published experimental data, we find that the determination of critical boundaries of the instability can be improved to some extent by considering the effect of vapor-
Study on electronic structures of PuH2 with DVM
Authors: Zhu Sheng Xiang  , Li Rui  , Yang Xiu Wen  , Xue Chun Rong  ,   同济大学波耳固体物理研究所，上海  200092
Published: December 2020

There is very little data public about the molecular structures and molecular spectroscopy for plutonium hydride. The fullelectronic structures in the molecule PuH2 are calculated with the discrete variational method (DVM) based upon the density functional theory. The optimal data of the ground level molecule PuH2 is as follows: bond angle(HH))=115.011°, bond length(PuH)=0208617nm,total orbital energy is -19838.6630 a.u., Fermi energy level is -12.571 eV. The comparisons of the results of full-electronic calculation with the frozen core calculation are given.
Mechanism of magnetization reversal in nanocrystalline Pr8Fe87B5
Authors: Zhang Hong-Wei  , Rong Chuan-Bing  , Zhang Jian  , Zhang Shao-Ying  , Shen Bao-Gen  ,   中国科学院物理研究所与凝聚态物理中心磁学国家重点实验室，北京  100080
Published: December 2020

Nanocomposite Pr2Fe14B/α-Fe was prepared by melt spinning. The magnetization reversal has been examined by the initial magnetization curve, recoil curve, minor hysteresis loops, applied field dependence of coercivity and remanence, and thermal activation. Inhomogeneous pinning controls mainly the coercivity in the melt-spun ribbons. Due to the intergrain exchange coupling between soft and hard phases, the magnetization reversal is different from that in traditional permanent magnets. Thermal activation is determined by the irreversible magnetization of the hard phase.
Influence of coupling between Er3+, nc-Si and nonradiative centers on photoluminescence from Er3+-doped nc-Si/SiO2 films
Authors: Chen Chang-Yong  , Chen Wei-De  , Wang Yong-Qian  , Song Shu-Fang  , Xu Zhen-Jia  ,   (1)中国科学院半导体研究所，北京  100083；; (2)中国科学院半导体研究所，北京  100083；中国科学院凝聚态物理中心，表面物理国家重点实验室，北京  100080
Published: December 2020

Correlation between nc-Si, Er3+ and nonradiative defects in Er-doped nc-Si/SiO2 films is studied. Upon the 514.5 nm laser excitation, the samples exhibit a nanocrystal-related spectrum centered at around 750 nm and an Er3+ luminescence line at 154μm. With increasing Er3+ content in the films,the Er3+ emission becomes intense while the photoluminescence at 750 nm decreases. Hydrogen passivation of the samples is shown to result in increases of the two luminescence peaks. However, the effect of hydrogen treatment is different for the samples annealed at different temperatures. The experimental results show that the coupling between Er3+, nc-Si and nonradiative centers has a great influence on photoluminescence from nc-Si/SiO2 films.
Spatiotemporal relation of prolongable general relativity in the irreversible process of a dissipative system
Authors: Li Zong-Cheng  ,   苏州大学东校区302信箱，苏州  215000
Published: December 2020

The hypothesis on the equivalence in non-conservative system is set up for irreversible process on the basis of bring-in of the nonconservative-noninertial system;and the hypothesis on the covariance in non-conservative system is put forth for the space-time with complex action on the basis of bring-in of the ultra-gauge. Also the heterogeneity h（ρt）and coarse-grained entropy S（ρtε）of the density distribution ρ in phase space and the derived computational expression of multiscale factor η* are used in the bring-in of the nonconsorvative gravitation mass and nonconservative inertial mass.The analysis here shows that the new result could make the gravitation theory, together with the statistical theory of nonequilibrium state and the nonlinear dynamics reach harmony to some extent, so as to revise and develop general theory of relativity.
Microcavity effects in the high modulation response of thevertical cavity surface emitting laser
Authors: Zhao Hong  Dong  , Kang ZhiLong  , Wang Sheng Li  , Chen Guo Ying  , Zhang YiMo  ,   (1)河北工业大学信息工程学院,天津  300130; (2)天津大学精密仪器与光电子工程学院，天津  300072
Published: December 2020

Based on physics of micro-cavity and quantum well, the spontaneous emission spectra and spontaneous emission lifetime in the vertical cavity surface emitting laser have been calculated. It is found that the minimum spontaneous emission lifetime is the main reason that the vertical cavity surface emitting laser can realize high\|modulation response after the transfer function of the semiconductor laser is studied.
Prediction of the chaotic time series using neuro-fuzzy networks
Authors: Tan Wen  , Wang Yao-Nan  , Zhou　Shao-Wu  , Liu　Zu-Run  ,   (1)湖南大学电气与信息工程学院,长沙  410082; (2)湘潭工学院信息与电气工程系,湘潭  411201; (3)湘潭工学院信息与电气工程系,湘潭  411201;湖南大学电气与信息工程学院,长沙  410082
Published: December 2020

A novel hybrid neural fuzzy inference system is presented. Only based on the desired input-output data pairs, are the knowledge acquisition and initial fuzzy rule sets available. Then, employing neural networks learning techniques, the fuzzy logic rules,input-output fuzzy membership functions and weights in networks can be easily tuned. So the rule matching is reduced ,inferencing is accelerated, adaptability of the system is greatly improved. To illustrate the performance of the proposed neuro-fuzzy hybrid model, simulations on the chaotic Mackey-Glass time series prediction are performed. Combining either off-line or on-line learning with the proposed hybrid model, we can show that the chaotic Mackey-Glass time series are accurately predicted, and demonstrate the effectivness of the model.
Study on nonlinear absorption and optical limiting properties in an organic material ZnTBP-CA-PhR
Authors: Yu Shi-Rui  , Zhao You-Yuan  , Li Lu-Ying  ,   先进光子学材料与器件国家重点实验室,复旦大学光科学与工程系,上海200433
Published: December 2020

In this paper the nonlinear absorption in the organic material ZnTBP-CA-PhR is reported. Saturable absorption, reverse saturable absorption and re-reverse saturable absorption under an Ar+ laser beam in visible light range were observed. This material has fine optical limiting properties. Its intensity threshold is lower than that of other materials and there is no nonlinear optical effect before input intensity reaches the threshold. In order to analyse the physical mechanism of nonlinear absorption of this material, a five-level model is presented using the rate equation theory to simulate the saturable absorption and reverse saturable absorption experimental results.
Power spectra density estimation of quality of the laserbeam passing through an selffocusing media
Authors: Peng Zhi-Tao  , Jing Feng  , Liu Lan-Qin  , Zhu Qi-Hua  , Chen Bo  , Zhang Kun  , Liu Hua  , hang Qing-Quan  , Cheng Xiao-Feng  , Jiang Dong-Bin  , Liu Hong-Jie  , Peng Han Sheng  ,   中国工程物理研究院激光聚变研究中心，绵阳919信箱988分箱621900
Published: December 2020

The method of Power spectra density was introduced to estimate the quality of a high intensity laser beam, and the near field of the self-focusing laser beam was analyzed. We obtained a certain ΔB restriction of the laser beam.The results of numerical simulations were coincident with the experimental data very well .
Oscillation properties of water droplets on a superhydrophobic surface and their correlations with droplet volume
Authors: Wang Kai-Yu , Pang Xiang-Long , Li Xiao-Guang ,   School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
Published: December 2020

In-depth understanding is limited to the oscillation properties of a droplet on a superhydrophobic surface, which are closely related to the contact line movement, droplet volume, and substrate amplitude, to name only a few factors. In the present work, we investigate the characteristics of droplet resonance amplitude, mode range, and resonance frequency, as well as their correlations with droplet volume (from 20 to 500 μL). In particular, the theoretical resonance frequency is mainly concerned and addressed. To this end, a model based on general hydrophobic surfaces proposed by Noblin et al. is employed, with its applicability to superhydrophobic surfaces examined. We propose a concept “virtual stationary point” for analyzing the errors from this model, with which we modify the model through using the correction coefficients. The main results are concluded as follows. 1) Under resonance, the change rate in droplet height rises with the increase of droplet volume and reduces with the increase of oscillation mode number. 2) Each number of oscillation mode corresponds to a frequency range, and the ends of adjacent mode ranges are connected to each other. These frequency ranges decrease with the increase of droplet volume. 3) Resonance frequency, f, decreases with the increase of droplet volume, V, and they are related approximated by f -V–0.4 under high mode numbers, which is different from f -V–0.5 as found on general hydrophobic surfaces. 4) Direct application of Noblin model to a superhydrophobic surface results in nonnegligible errors, because geometric characteristics in this case are different from those on a general hydrophobic surface, which leads to inaccuracy in counting the number of surface wave segments. In contrast, results from modified Noblin model accord well with experimental results.
Antifeedant Activity of Pyrazolin-5-One Derivatives
Authors: Patel R. , Singh G. , Mandal S. , Singh M. K.
Published: December 2020

A series of substituted 4-{1-aza-2-[(aryl) amino)]}-3-methyl-2-pyrazolin-5-ones has been synthesized and evaluated for their biological activity. The title compounds (4a-l) were prepared by the diazotization of substituted anilines (1a-l) to form substituted phenyl hydrazine derivatives (2a-l) which synthesized substituted 4-{1-aza-2-[(aryl) amino)]}-3-methyl-2-pyrazolin-5-ones (4a-l) by Michael addition reaction, which is a nucleophilic addition of enolate anion to the carbon-carbon double bond of a α, β–unsaturated carboxylic acid derivatives. Twelve different pyrazolinone derivatives (4a to 4l) were synthesized. Structural assignments of these compounds have been made by elemental analysis, FTIR, 1HNMR and Mass spectral data and the purity of the compounds was determined by TLC. The antifeedant activity of the newly isolated heterocyclic compounds was evaluated against agriculture pest Achoea janata. Compound 4d found to be very effective as antifeedant while rest of the compounds showed a moderate to good degree of antifeedant activity.
The coordinated action of glucuronoyl esterase and α‐glucuronidase promotes the disassembly of lignin–carbohydrate complexes
Authors: Raji Olanrewaju , Arnling Bååth Jenny , Vuong Thu V. , Larsbrink Johan , Olsson Lisbeth , Master Emma R.
Published: December 2020

Glucuronoxylans represent a significant fraction of woody biomass, and its decomposition is complicated by the presence of lignin–carbohydrate complexes (LCCs). Herein, LCCs from birchwood were used to investigate the potential coordinated action of a glucuronoyl esterase (TtCE15A) and two α‐glucuronidases (SdeAgu115A and AxyAgu115A). When supplementing α‐glucuronidase with equimolar quantities of TtCE15A, total MeGlcpA released after 72 h by SdeAgu115A and AxyAgu115A increased from 52% to 67%, and 61% to 95%, respectively. Based on the combined TtCE15A and AxyAgu115A activities, ~ 34% of MeGlcpA in the extracted birchwood glucuronoxylan was occupied as LCCs. Notably, insoluble LCC fractions reduced soluble α‐glucuronidase concentrations by up to 70%, whereas reduction in soluble TtCE15A was less than 30%, indicating different tendencies to adsorb onto the LCC substrate.
Children With Enthesitis‐Related Arthritis and Possible Benefits From Treatments for Adults With Spondyloarthritis
Authors: Weiss Pamela F. , Fuhlbrigge Robert C. , von Scheven Emily , Lovell Daniel J. , Colbert Robert A. , Brunner Hermine I. ,   for the PRCSG Advisory Council and the CARRA Executive Committee
Published: December 2020

This review will summarize clinical, genetic, and pathophysiologic characteristics that are shared between children with enthesitis‐related arthritis (ERA) with axial involvement and adults with nonradiographic (and in some cases radiographic) axial spondyloarthritis (SpA), as well as between children with ERA and primarily peripheral disease manifestations and adults with peripheral SpA. Due to the differences in classification criteria for children with ERA and adults with axial and peripheral SpA, the US Food and Drug Administration (FDA) granted automatic full waivers of studies in children for new medications for “axial spondyloarthropathies including ankylosing spondylitis” up until July 2020. Thus, although current juvenile idiopathic arthritis treatment guidelines recommend the use of biologic disease‐modifying antirheumatic drugs as part of the early treatment for patients with ERA, none of the FDA‐approved therapies for peripheral SpA or nonradiographic axial SpA (certolizumab pegol, ixekizumab, and secukinumab) have been studied or are labeled for use in children with ERA. Considering the similarities between adult SpA and ERA in terms of etiology, genetics, pathogenesis, and clinical manifestations summarized in this review, medications approved for axial SpA or peripheral SpA should also be studied in children with active ERA involving axial or peripheral joints, respectively, with the intent to achieve labeling for use in children. Considering the current lack of effective FDA‐approved therapies for ERA, the FDA should also consider requiring pediatric studies for medications that have already been approved for the treatment of adults with SpA.
Objective and subjective measurement of sedentary behavior in human adults: A toolkit
Authors: Aunger Justin , Wagnild Janelle
Published: December 2020

Objectives

Objectives: Human biologists are increasingly interested in measuring and comparing physical activities in different societies. Sedentary behavior, which refers to time spent sitting or lying down while awake, is a large component of daily 24 hours movement patterns in humans and has been linked to poor health outcomes such as risk of all‐cause and cardiovascular mortality, independently of physical activity. As such, it is important for researchers, with the aim of measuring human movement patterns, to most effectively use resources available to them to capture sedentary behavior.

Methods

This toolkit outlines objective (device‐based) and subjective (self‐report) methods for measuring sedentary behavior in free‐living contexts, the benefits and drawbacks to each, as well as novel options for combined use to maximize scientific rigor. Throughout this toolkit, emphasis is placed on considerations for the use of these methods in various field conditions and in varying cultural contexts.

Results

Objective measures such as inclinometers are the gold‐standard for measuring total sedentary time but they typically cannot capture contextual information or determine which specific behaviors are taking place. Subjective measures such as questionnaires and 24 hours‐recall methods can provide measurements of time spent in specific sedentary behaviors but are subject to measurement error and response bias.

Conclusions

We recommend that researchers use the method(s) that suit the research question; inclinometers are recommended for the measurement of total sedentary time, while self‐report methods are recommended for measuring time spent in particular contexts of sedentary behavior.
Robinow syndrome: Genital analysis, genetic heterogeneity, and associated psychological impact
Authors: Gerber Jonathan A. , Sheth Kunj R. , Austin Paul F.
Published: December 2020

Robinow syndrome (RS) is a rare, pleiotropic genetic disorder. While it has been reported that males with Robinow syndrome may have genitourinary atypicalities, these have not been systematically studied. We hypothesized that the underlying gene involved plays a role in the clinical variability of associated genital findings and that the phenotypic appearance of the genitalia in RS may have a psychological impact. Urologic‐specific examination consisted of detailed examination and a questionnaire to investigate the psychological impact of the genital phenotype. Nine males agreed to a full evaluation. Average age was 19.9 years, penile length was 32.5 mm, stretched length 53 mm, and width 24.4 mm. Penile transposition occurred in all 9 male who allowed full examination. Undescended testicles were noted in 4/10, testicular atrophy in 5/9, buried penis in 7/9, hypospadias in 5/8, and a large penopubic gap (space between dorsum of penis base and pubic bone) in 5/6. In this cohort, 78% answered our semi‐quantitative pilot questionnaire that identified diminished sexuality, sexual function, and self‐perception. In conclusion, RS has unique, hallmark genital findings including penile transposition, buried penis, undescended testes, and large penopubic gaps. Genital phenotype in males was not shown to correlate with the specific gene involved for each patient. Surgical approaches and other interventions should be studied to address the findings of decreased sexuality and self‐perception. It is the authors' opinion that intervention to provide the appearance of penile lengthening be postponed until puberty to allow for maximal natural phallic growth.
Gold(I)‐Catalyzed Intramolecular Hydroarylation of o‐Ethynylarylphosphonium Salt Leading to the Formation of Seven‐ and Six‐membered Phosphacycles
Authors: Tsurusaki Akihiro , Shimatani Hiroki , Kamikawa Ken
Published: December 2020

The gold(I)‐catalyzed intramolecular hydroarylation of o‐ethynylarylphosphonium salt 1 gave phosphepinium 2 or phosphinium salt 3. The use of methylphosphonium salt instead of phosphine chalcogenide is key to success for the intramolecular hydroarylation. The substrate with 2‐methoxyphenyl group at the alkyne position preferentially provided seven‐membered phosphacycle 2, while that with a hydrogen did six‐membered phosphacycle 3. Theoretical calculations revealed that the activation energy of 6‐exo‐dig cyclization in the substrate with the aryl group increased due to the steric repulsion of the two aryl rings. Furthermore, the Wittig‐type reaction of phosphepinium salt 2 a afforded methyl‐substituted phosphepin oxide 4 a via the elimination of an aryl group.
Combining ion chromatography with mass spectrometry and inductively coupled plasma‐mass spectrometry: Annual review 2020
Authors: Bruggink Cees , Jensen Detlef
Published: December 2020

The demand for analyzing low molecular weight polar and ionic components in body fluids, pharmaceutical formulations, food, environmental samples, and drinking water is increasing. Ion chromatography (IC) offers significant advantages over RPLC and HILIC due to a complementary chromatographic selectivity, a different retention mechanism, and a high tolerance toward complex matrices. A continuously regenerated membrane desalter simplifies the combination of IC‐applications with MS‐ or MS/MS‐detection, improving the sensitivity and specificity. Analytical workflows are streamlined, providing higher sample throughput. Combining IC with ICP‐MS simplifies the speciation analysis of inorganic and organic polar components. The knowledge about the distribution of an element among chemical species in a sample is essential due to significantly different toxicological or environmental properties. This annual review evaluates the literature published from late 2019 until November 2020.
American College of Rheumatology Guidance for the Management of Rheumatic Disease in Adult Patients During the COVID‐19 Pandemic: Version 3
Authors: Mikuls Ted R. , Johnson Sindhu R. , Fraenkel Liana , Arasaratnam Reuben J. , Baden Lindsey R. , Bermas Bonnie L. , Chatham Winn , Cohen Stanley , Costenbader Karen , Gravallese Ellen M. , Kalil Andre C. , Weinblatt Michael E. , Winthrop Kevin , Mudano Amy S. , Turner Amy , Saag Kenneth G.
Published: December 2020

Objective

To provide guidance to rheumatology providers on the management of adult rheumatic disease in the context of the coronavirus disease 2019 (COVID‐19) pandemic.

Methods

A task force, including 10 rheumatologists and 4 infectious disease specialists from North America, was convened. Clinical questions were collated, and an evidence report was rapidly generated and disseminated. Questions and drafted statements were reviewed and assessed using a modified Delphi process. This included asynchronous anonymous voting by email and webinars with the entire panel. Task force members voted on agreement with draft statements using a 1–9‐point numerical scoring system, and consensus was determined to be low, moderate, or high based on the dispersion of votes. For approval, median votes were required to meet predefined levels of agreement (median values of 7–9, 4–6, and 1–3 defined as agreement, uncertainty, or disagreement, respectively) with either moderate or high levels of consensus.

Results

Draft guidance statements approved by the task force have been combined to form final guidance.

Conclusion

These guidance statements are provided to promote optimal care during the current pandemic. However, given the low level of available evidence and the rapidly evolving literature, this guidance is presented as a “living document,” and future updates are anticipated.
Student mobility and school segregation in an (un)controlled choice system: A counterfactual approach
Authors: Bonal Xavier , Zancajo Adrián , Scandurra Rosario
Published: December 2020

This article explores the relationship between school choice, student mobility and school segregation in Barcelona. The case of Barcelona is particularly interesting because the school admissions policy combines a particular design of catchment area with a significant level of choice options. We work on students and school register datasets for the school year 2016–2017 to observe the association between the socioeconomic characteristics of the students and their residential and educational geographical distribution. The article tests whether recent reforms that have undermined the role of residential proximity in admissions policy have impacted on the school segregation of three groups of socially disadvantaged students (foreign students, students entitled to Free School Meals (FSM) and students who are Recipients of Social Allowances (RSA)). We explore different patterns of mobility between socially disadvantaged and non‐disadvantaged students and the impact of opting out from neighbourhood schools on school segregation. By using a counterfactual approach that compares real enrolment with simulated school enrolment in proximity schools, we provide evidence of a significant reduction of school segregation for all socially disadvantaged students, showing the negative effects of the current high number of school choice options. In addition, our analysis shows that school choice boosts remarkably the inequality between public and private subsidised schools. The final section of the article reflects on the implications of our findings for potential reforms in the current definition of catchment areas and the overall school choice policy in Barcelona.
Poloxamer 407‐based Floating Hydrogels for Intravesical Instillation: Statistical Optimization Using Central Composite Design, Gel Erosion, and Drug Release
Authors: Yang Hee Mang , Yoon Ho Yup , Kim Chang Hyun , Goo Yoon Tae , Choi Ik Joon , Park Sang‐Gue , Chang In Ho , Choi Young Wook
Published: December 2020

Poloxamer 407 (POL) is widely used as a thermosensitive hydrogel for intravesical instillation. When POL hydrogel is instilled in the bladder, several problems, including urinary tract obstruction, are observed. To overcome this problem, a POL‐based floating hydrogel (PFH) system was developed. Sodium bicarbonate (BC) was used as a floating agent. PFH was optimized using a central composite design with two independent variables (X1 [POL concentration, 42.43%] and X2 [BC concentration, 5.23%]) and three response factors (Y1 [floating time, 240.33 s], Y2 [duration time, 270 min], and Y3 [viscosity, 110.39 Pa.s]). In gel erosion and drug‐release studies in vitro, the remaining PFH fraction decreased exponentially with time, while gemcitabine release was biphasic and surface erosion‐controlled. A plot of drug release versus gel erosion showed good linearity. Visual observation for floating, gel duration, and dye release supported the time‐course behaviors of the PFH, indicating its usefulness in intravesical instillation.
Polydiacetylenes Containing 2‐Picolylamide Chemosensor for Colorimetric Detection of Cadmium Ions
Authors: Kim Yong Kyun , Pham Thanh Chung , Kim Jaewon , Bae Chaeeon , Choi Yeonghwan , Jo Min Hee , Lee Songyi
Published: December 2020

This article describes the preparation and analysis of Cd2+‐sensing polydiacetylene‐based chemosensors (PDA‐MP). Polydiacetylenes (PDAs), a family of conjugated polymers, exhibit a strong response to external stimuli. Accordingly, we have designed a novel PDA sensor, which is linked to mono 2‐picolylamine, to increase the PCDA‐MP monomer content in polymer system. As a result, it enhanced sensitivity toward Cd2+ with the low detection limit (2.10 μM) in aqueous solution. Our sequential modification of chelate structure improved the Cd2+‐sensing ability of PDAs. Finally, the interaction between PCDA–MP and Cd2+ was confirmed by Raman spectroscopy, Field Emission Scanning Electron Microscopes (FE‐SEM), and Proton nuclear magnetic resonance (1H NMR).
Crosslinking of Streptavidin–Biotinylated Bovine Serum Albumin Studied with Fluorescence Correlation Spectroscopy
Authors: Lee Sujin , Kim Hahkjoon
Published: December 2020

The strong binding between streptavidin (SA) and biotin has been used as a useful tool in the study of biological system. When SA is mixed with biotinylated bovine serum albumin (bBSA), aggregates are formed by crosslinking. We employed fluorescence correlation spectroscopy to determine the hydrodynamic radius of SA‐bBSA aggregates. We found that their hydrodynamic radius depends on the molar ratio of SA to bBSA, with the maximum radius being observed for 4:1 SA to bBSA. When the molar ratio of SA to bBSA was 6:1, the size of the aggregates decreased sharply because the SA molecules surround the bBSA and as a result, crosslinking is greatly reduced. Based on the hydration radius of the aggregates, we estimate that 7 to 8 SA molecules were bound to one bBSA.
Unilateral Purtscher‐like retinopathy as the presenting feature of a case with spontaneous carotid artery dissection
Authors: İpek Şefik Can , Yaman Aylin , Men Süleyman , Saatci Ali Osman
Published: December 2020

Carotid artery dissection should be considered in the differential diagnosis when a clinician faces with a case presenting with a unilateral Purtscher‐like retinopathy.
SALAD‐BAAR: A numerical risk score for hospital admission or emergency department presentation in ambulatory patients with cardiovascular disease
Authors: Anyanwu Emeka C. , Chua Rhys F. M. , Besser Stephanie A. , Sun Deyu , Liao James K. , Tabit Corey E.
Published: December 2020

Background

While many interventions to reduce hospital admissions and emergency department (ED) visits for patients with cardiovascular disease have been developed, identifying ambulatory cardiac patients at high risk for admission can be challenging.

Hypothesis

A computational model based on readily accessible clinical data can identify patients at risk for admission.

Methods

Electronic health record (EHR) data from a tertiary referral center were used to generate decision tree and logistic regression models. International Classification of Disease (ICD) codes, labs, admissions, medications, vital signs, and socioenvironmental variables were used to model risk for ED presentation or hospital admission within 90 days following a cardiology clinic visit. Model training and testing were performed with a 70:30 data split. The final model was then prospectively validated.

Results

A total of 9326 patients and 46 465 clinic visits were analyzed. A decision tree model using 75 patient characteristics achieved an area under the curve (AUC) of 0.75 and a logistic regression model achieved an AUC of 0.73. A simplified 9‐feature model based on logistic regression odds ratios achieved an AUC of 0.72. A further simplified numerical score assigning 1 or 2 points to each variable achieved an AUC of 0.66, specificity of 0.75, and sensitivity of 0.58. Prospectively, this final model maintained its predictive performance (AUC 0.63–0.60).

Conclusion

Nine patient characteristics from routine EHR data can be used to inform a highly specific model for hospital admission or ED presentation in cardiac patients. This model can be simplified to a risk score that is easily calculated and retains predictive performance.
Coinage Metal N‐Heterocyclic Carbene Complexes: Recent Synthetic Strategies and Medicinal Applications
Authors: Nayak Swarnagowri , Gaonkar Santosh L.
Published: December 2020

New weapons are constantly needed in the fight against cancer. The discovery of cisplatin as an anticancer drug prompted the search for new metal complexes. The successful history of cisplatin motivated chemists to develop a plethora of metal‐based molecules. Among them, metal‐N‐heterocyclic carbene (NHC) complexes have gained significant attention because of their suitable qualities for efficient drug design. The enhanced applications of coinage metal‐NHC complexes have encouraged a gradually increasing number of studies in the fields of medicinal chemistry that benefit from the fascinating chemical properties of these complexes. This review aims to present recent developments in synthetic strategies and medicinal applications of copper, silver and gold complexes supported by NHC ligands.
The tale of proteolysis targeting chimeras (PROTACs) for Leucine‐Rich Repeat Kinase 2 (LRRK2)
Authors: Konstantinidou Markella , Oun Asmaa , Pathak Pragya , Zhang Bidong , Wang Zefeng , ter Brake Frans , Dolga Amalia M. , Kortholt Arjan , Dömling Alexander
Published: December 2020

Here we present the rational design and synthetic methodologies towards proteolysis‐targeting chimeras (PROTACs) for the recently‐emerged target leucine‐rich repeat kinase 2 (LRRK2). Two highly potent, selective, brain‐penetrating kinase inhibitors were selected, and their structure was appropriately modified to assemble a cereblon‐targeting PROTAC. Biological data show strong kinase inhibition and the ability of the synthesized compounds to enter the cells. However, data regarding the degradation of the target protein are inconclusive. The reasons for the inefficient degradation of the target are further discussed.
Functional, molecular and morphological heterogeneity of superficial interneurons in the larval zebrafish tectum
Authors: Barker Alison J. , Helmbrecht Thomas O. , Grob Aurélien A. , Baier Herwig
Published: December 2020

The superficial interneurons, SINs, of the zebrafish tectum, have been implicated in a range of visual functions, including size discrimination, directional selectivity, and looming‐evoked escape. This raises the question if SIN subpopulations, despite their morphological similarities and shared anatomical position in the retinotectal processing stream, carry out diverse, task‐specific functions in visual processing, or if they have simple tuning properties in common. Here we have further characterized the SINs through functional imaging, electrophysiological recordings, and neurotransmitter typing in two transgenic lines, the widely used Gal4s1156t and the recently reported LCRRH2‐RH2‐2:GFP. We found that about a third of the SINs strongly responded to changes in whole‐field light levels, with a strong preference for OFF over ON stimuli. Interestingly, individual SINs were selectively tuned to a diverse range of narrow luminance decrements. Overall responses to whole‐field luminance steps did not vary with the position of the SIN cell body along the depth of the tectal neuropil or with the orientation of its neurites. We ruled out the possibility that intrinsic photosensitivity of Gal4s1156t+ SINs contribute to the measured visual responses. We found that, while most SINs express GABAergic markers, a substantial minority express an excitatory neuronal marker, the vesicular glutamate transporter, expanding the possible roles of SIN function in the tectal circuitry. In conclusion, SINs represent a molecularly, morphologically, and functionally heterogeneous class of interneurons, with subpopulations that detect a range of specific visual features, to which we have now added narrow luminance decrements.
Ligand‐Protected Ultrasmall Pd Nanoclusters Supported on Metal Oxide Surfaces for CO Oxidation: Does the Ligand Activate or Passivate the Pd Nanocatalyst?
Authors: Farrag Mostafa , Das Mrinmoy K. , Moody Michael , Samy El‐Shall M.
Published: December 2020

Herein, we report on the synthesis of ultrasmall Pd nanoclusters (∼2 nm) protected by L‐cysteine [HOCOCH(NH2)CH2SH] ligands (Pdn(L‐Cys)m) and supported on the surfaces of CeO2, TiO2, Fe3O4, and ZnO nanoparticles for CO catalytic oxidation. The Pdn(L‐Cys)m nanoclusters supported on the reducible metal oxides CeO2, TiO2 and Fe3O4 exhibit a remarkable catalytic activity towards CO oxidation, significantly higher than the reported Pd nanoparticle catalysts. The high catalytic activity of the ligand‐protected clusters Pdn(L‐Cys)m is observed on the three reducible oxides where 100 % CO conversion occurs at 93–110 °C. The high activity is attributed to the ligand‐protected Pd nanoclusters where the L‐cysteine ligands aid in achieving monodispersity of the Pd clusters by limiting the cluster size to the active sub‐2‐nm region and decreasing the tendency of the clusters for agglomeration. In the case of the ceria support, a complete removal of the L‐cysteine ligands results in connected agglomerated Pd clusters which are less reactive than the ligand‐protected clusters. However, for the TiO2 and Fe3O4 supports, complete removal of the ligands from the Pdn(L‐Cys)m clusters leads to a slight decrease in activity where the T100% CO conversion occurs at 99 °C and 107 °C, respectively. The high porosity of the TiO2 and Fe3O4 supports appears to aid in efficient encapsulation of the bare Pdn nanoclusters within the mesoporous pores of the support.
Long‐Chain Ionic Liquids Based on Monoquaternary DABCO Cations and TFSI Anions: Towards Stable Electrolytes for Electrochemical Capacitors
Authors: Turguła Anna , Graś Małgorzata , Gabryelczyk Agnieszka , Lota Grzegorz , Pernak Juliusz
Published: December 2020

The desirable properties of ionic liquids (ILs) enable their use in various branches of chemistry, through a wide range of applications, e. g. as organic electrolytes. In the present study, an efficient two‐step method was developed for the synthesis of long‐chain ionic liquids with alkyl derivatives of DABCO as cations and bis(trifluoromethane)sulfonimide as anions. ILs obtained with high yields (≥91 %) were solids with melting points that increased with the rise in the number of carbon atoms of the alkyl substituent in the bicyclic cation. The structure of the compounds was confirmed by spectroscopic methods and elemental analysis. All compounds were soluble in the main solvents except water and hexane. The solubility in organic solvents such as acetonitrile allowed the use of synthesized ILs in electrochemical capacitors. Electrochemical tests revealed that the ILs enhanced the conductivity of organic electrolytes. This phenomenon improved the cyclability and reduced the internal resistance of the electrochemical capacitors.
Flow cytometry‐based analysis of tumor‐leukocyte ratios in peritoneal fluid from patients with advanced gastric cancer
Authors: Takahashi Kazuya , Kurashina Kentaro , Saito Shin , Kanamaru Rihito , Ohzawa Hideyuki , Yamaguchi Hironori , Miyato Hideyo , Hosoya Yoshinori , Lefor Alan Kawarai , Sata Naohiro , Kitayama Joji
Published: December 2020

Background

The frequency of tumor cell dissemination in the peritoneal cavity is critically related to the progression of peritoneal metastases (PM). Recently, flow cytometry (FCM) has been successfully used to detect tumor cells in malignant effusions.

Methods

A total of 143 single cell suspensions derived from ascites or peritoneal lavages from patients with advanced gastric cancer (GC) were stained with monoclonal antibodies to CD45 and to CD326 as well as 4,6‐diamidino‐2‐phenylindole (DAPI) and FVS780. Using FCM, tumor‐leukocyte ratio (TLR) were calculated from CD45(−)CD326(+) tumor cell counts/ CD45(+)CD326(+) leukocyte counts in DAPI (+) FVS780(−) gated area. In 54 patients, the ratios of CD11b(+), CD4(+) and CD8(+) cells in CD45(+) leukocytes were evaluated in parallel.

Results

TLR of 69 patients with PM were significantly higher than those of 74 without PM (p < .001) and log(TLR) showed strong correlation with peritoneal cancer index scores in 51 PM (+) patients (r = 0.439). TLR in PM (+) patients also correlated with the ratio of CD11b (+) myeloid cells (r = 0.547), and correlated inversely with those of CD4(+) (r = −0.490) and CD8(+) T cells (r = −0.648). In PM (−) patients who underwent gastrectomy, TLR never exceeded 0.1% in patients with primary GC without serosal involvement (<T4). However, TLR in patients with T4 GC were significantly higher (p < .05) and peritoneal recurrence occurred in 6/8 patients whose TLR exceeded 0.1%.

Conclusion

TLR in peritoneal fluid reflects tumor burden and the immune environment in peritoneal cavity. Multicolor FCM may provide additional information which can be used for the treatment of the patients with PM.
Morphological changes in the central sulcus of children with isolated growth hormone deficiency versus idiopathic short stature
Authors: Zhang Zhonghe , Wang Yu , Gao Yue , Li Zhuoran , Zhang Shuhan , Lin Xiangtao , Hou Zhongyu , Yu Qiaowen , Wang Ximing , Liu Shuwei
Published: December 2020

In this study, the morphological changes in the central sulcus between children with isolated growth hormone deficiency (IGHD) and those with idiopathic short stature (ISS) were analyzed. Thirty children with IGHD (peak growth hormone < 5 µg/L) and 30 children with ISS (peak growth hormone > 10.0 µg/L) were included. Morphological measurements of the central sulcus were obtained from T1‐weighted MRIs using BrainVISA, including the average sulcal width, maximum depth, average depth, top length, bottom length, and depth position‐based profiles (DPPs). The bilateral average width of the central sulci was significantly wider, while the left maximum depth and right average depth of the central sulcus were significantly smaller, in children with IGHD than in children with ISS. There were no significant differences in the right maximum depth, left average depth, or bilateral top length and bottom length of the central sulcus between groups. The DPPs of the middle part of both central sulci (corresponding to the hand motor activation area) and the inferior part of the right central sulcus (corresponding to the oral movement area) near the Sylvian fissure were significantly smaller in children with IGHD than in controls before false discovery rate (FDR) correction. However, all the above significant DPP sites disappeared after FDR correction. There were significant morphological changes in the three‐dimensional structure of the central sulcus in children with IGHD, which were the outcome of other more essential cortical or subcortical changes, resulting in their relatively slower development in motor, cognitive, and linguistic functional performance.