bluuebunny/crossref_metadata_2025 huggingface dataset:
A GLP-2 Analogue Protects SH-SY5Y and Neuro-2a Cells Against Mitochondrial Damage, Autophagy Impairments and Apoptosis in a Parkinson Model
Authors: Su Yunfang , Zhang Zijuan , Li Hao , Ma Jinlian , Sun Limin , Shao Simai , Zhang Zhenqiang , Hölscher Christian
Published: October 2020

Glucagon-like peptide-2 (GLP-2) is a peptide hormone that belongs to the glucagon-derived peptide family. We have previously shown that analogues of the sister hormone Glucagon-like peptide-1 (GLP-1) showed neuroprotective effects. Here we investigated the effect of a GLP-2 agonist in a cell model of Parkinsonʼs disease (PD) created by treating SH-SY5Y or Neuro-2a cells with 1-Methyl-4-phenyl-pyridine ion (MPP+). Cell viability and cell cytotoxicity was detected by MTT and LDH assays, respectively. The protein expression levels of mitochondrial, autophagy and apoptotic biomarkers including PGC-1α, Mfn2, IRE1, ATG7, LC3B, Beclin1 and Bcl-2 were detected by western blot. Mitochondrial superoxide was detected by MitoSOX Red. In addition, mitochondrial morphology, autophagosome and apoptotic corpuscles were observed by transmission electron microscope (TEM). We found that the GLP-1 and the GLP-2 agonists both protect cells against mitochondrial damage, autophagy impairments and apoptosis induced by MPP+both in SH-SY5Y and Neuro-2a cells. Cell signaling for mitogenesis was enhanced, and oxidative stress levels much reduced by the drugs. This demonstrates for the first time the neuroprotective effects of a GLP-2 analogue in PD cellular models, in which oxidative stress, autophagy and apoptosis play crucial roles. The protective effects were comparable to those seen with the GLP-1 analogue liraglutide. The results suggest that not only GLP-1, but also GLP-2 has neuroprotective properties and may be useful as a novel treatment of PD.
Estado de la urología reconstructiva en Colombia: Tratamiento de la estrechez uretral anterior, una encuesta nacional
Authors: Patiño Germán A. , Carreño Gabriel L. , Gwinner Juan Guillermo Prada , Perez Jaime
Published: October 2020

Purpose El tratamiento mínimamente invasivo de la estrechez uretral tiene altas tasas de recurrencia y re-operación a largo plazo, no obstante, encuestas realizadas en otros países han demostrado que los urólogos tienen poca experiencia con la uretroplastia abierta y hay una preferencia a la utilización de las terapias endoscópicas mínimamente invasivas. El objetivo de este estudio, es describir patrones de práctica del tratamiento de la estrechez de uretra anterior en nuestro país.

Métodos Se trata de un estudio observacional descriptivo y para ello se realizó un cuestionario adaptado a nuestro contexto nacional, basado en varios estudios previamente realizados acerca de la experiencia en Urología reconstructiva. Ese cuestionario incluía información sobre la edad, nivel de experiencia en urología general, la experiencia en urología reconstructiva, escenario de la práctica y las técnicas preferidas para el manejo de las estrecheces uretrales pendulares y bulbares. La información fue almacenada de forma anónima, los datos fueron analizados mediante el paquete estadístico SPSS y se realizó un análisis de distribución de frecuencias.

Resultados Se obtuvieron 106 respuestas de los urólogos encuestados. Para el tratamiento de la estrechez uretral pendular la mayoría de los urólogos prefiere el manejo endoscópico mínimamente invasivo, seguido de uretroplastia con injerto con porcentajes de 69,9% y 25,5% respectivamente. Solo el 5% prefiere derivar a sus pacientes a un centro especializado. Para la estrechez de la uretra bulbar se prefiere las técnicas mínimamente invasivas, uretroplastia y remisión a un centro especializado en un 44,3%, 41,5% y 14,2% respectivamente. La población más joven y con formación urológica más reciente tiende a hacer más a menudo la uretroplastia con injerto y menos manejo endoscópico, específicamente la uretrotomía interna. En las ciudades intermedias, hay una predilección por el tratamiento endoscópico, especialmente uretrotomía interna.

Conclusiones El enfoque de tratamiento mínimamente invasivo de la estrechez uretral es el más frecuentemente elegido a pesar de sus pobres tasas de éxito a largo plazo. Es de destacar que las nuevas generaciones de urólogos muestran más interés y dominio de las técnicas abiertas, tratamiento estándar hoy en día y con bajas tasas de recaídas y reoperación a largo plazo.
Predictors of PROMIS Physical Function at 2 Years following Knee Surgery
Authors: Hunt Darius , Zhang Tina , Koenig Scott , Aneizi Ali , Perraut Gregory , Shasti Keyan , Wahl Alexander J. , Meredith Sean J. , Henn R. Frank
Published: October 2020

The purpose of this study was to evaluate Patient-Reported Outcomes Measurement Information System physical function (PROMIS PF) 2 years following knee surgery, and identify preoperative factors associated with postoperative PROMIS PF. Three hundred and sixty-five patients, age 17 years and older, undergoing knee surgery at one institution were studied. Patients completed multiple questionnaires prior to surgery and again 2 years postoperatively including PROMIS PF, International Knee Documentation Committee (IKDC), joint and body numeric pain scales (NPS), Tegner's activity scale (TAS), and Marx's activity rating scale (MARS). Mean PROMIS PF improved from 41.4 to 50.9 at 2 years postoperatively (p < 0.001) and was strongly correlated with 2-year IKDC scores. Older age, female gender, non-Hispanic ethnicity, unemployment, lower income, government insurance, smoking, preoperative opioid use, having a legal claim, comorbidities, previous surgeries, higher body mass index (BMI), and knee arthroplasty were associated with worse 2-year PROMIS PF. Multivariable analysis confirmed that lower BMI, less NPS body pain, and higher MARS were independent predictors of greater 2-year PROMIS PF and better improvement in PROMIS PF. In this large, broad cohort of knee surgery patients, multiple preoperative factors were associated with PROMIS PF 2 years postoperatively. PROMIS PF scores improved significantly, but worse 2 year PROMIS PF scores and less improvement from baseline were independently predicted by higher BMI, greater NPS body pain, and lower MARS activity level. PROMIS PF can be implemented as an efficient means to assess outcomes after knee surgery.
Risk Factors for New Meniscal Tears following Anterior Cruciate Ligament Reconstruction
Authors: Chan Chloe Xiaoyun , Silas Christian , Ifran Nadia Nastassia , Mok Ying Ren , Krishna Lingaraj
Published: October 2020

This study aims to compare the rate of meniscal tears after anterior cruciate ligament (ACL) reconstruction in patients who have undergone concomitant meniscal repair during the index procedure with that in patients who have not undergone such surgery. It also evaluates other risk factors, such as age, gender, race, body mass index (BMI), site of concomitant meniscal surgery, and ACL graft failure. This is a retrospective study conducted at a large tertiary public hospital. Patients who underwent primary anterior cruciate ligament reconstruction (ACLR) surgery with or without concomitant meniscal repair from 2011 to 2016 were identified. Patients with old meniscal tears and previous meniscal surgeries were excluded. The aforementioned demographical, injury, and surgical details were obtained and analyzed using univariate and multivariate logistic regression analysis. Our study cohort included 754 patients. Primary ACLR surgery was performed with meniscal repair in 172 (22.8%) of the patients, with meniscectomy in 202 (26.8%) of the patients, and without concomitant meniscal surgery in 380 (50.4%) of the patients. A total of 81 (10.7%) patients developed meniscal tears after the index procedure. Such tears occurred in 12.2% (21 of 172) of the patients who had undergone concomitant meniscal repair during the index ACLR, and in 10.3% (60 of 582) of the patients who had not undergone concomitant meniscal repair (p = 0.30). On multivariate analysis, only ACL graft failure was significantly associated with new meniscal tears (p < 0.001, odds ratio 18.69, 95% confidence interval 9.18–38.05). ACL graft failure is the only independent risk factor for meniscal tears after ACLR surgery in our large cohort of patients. Concomitant meniscal repair was not an associated risk factor.
Increased Risk of Short-Term Complications in Smokers Undergoing Primary Unicompartmental Knee Arthroplasty
Authors: Carender Christopher N. , DeMik David E. , Bedard Nicholas A. , Glass Natalie A. , Brown Timothy S.
Published: October 2020

The effects of smoking on unicompartmental knee arthroplasty (UKA) are unknown. The purpose of this study was to evaluate the effects of smoking on short-term outcomes following primary UKA. A query of the National Surgical Quality Improvement Project (NSQIP) database was used to identify cases of primary UKA performed during years 2006 to 2017. Patient demographics, operative times, and postoperative complications were compared between smoking and nonsmoking cohorts. Descriptive statistics, univariate analyses, and multivariate analyses were conducted to evaluate the effects of smoking on primary UKA. A total of 10,593 cases of UKA were identified; 1,046 of these patients were smokers. Univariate analysis demonstrated smokers to have higher rates of any complication (4.6 vs. 3.3%, p = 0.031), any wound complication (1.82 vs. 0.94%, p = 0.008), deep wound infection (0.57 vs. 0.13%, p = 0.006), and reoperation (1.34 vs. 0.68%, p = 0.018) relative to nonsmokers. Multivariate analysis demonstrated smokers to have higher rates of any wound complication (odds ratio [OR] = 1.79; 95% confidence interval [CI]: 1.06–2.95) and reoperation (OR = 2.11; 95% CI: 1.12–3.97). Smokers undergoing primary UKA are at higher risk for any wound complication and reoperation relative to nonsmokers in the first 30 days postoperatively. Further studies evaluating the long-term effects of smoking on outcome following UKA, as well as the impact of smoking cessation on outcomes following UKA, are needed.
Central Transpatellar Tendon Portal Is Safe When Used for Anterior Cruciate Ligament Reconstruction
Authors: Perelli Simone , Erquicia Juan Ignacio , Morales Marin Carlos , Bracamonte Salgado William Teodoro , Masferrer-Pino Angel , Perez-Prieto Daniel , Monllau Juan Carlos
Published: October 2020

Central transpatellar tendon portal (CTP) was suggested first for complex meniscal lesion and subsequently for a better femoral footprint view during reconstruction of anterior cruciate ligament (ACL). A comprehensive evaluation of possible consequences of using the CTP performing an ACL reconstruction does not exist. Our hypothesis was that the use of CTP for ACL reconstruction does not lead to a higher rate of complications or clinically evident radiological abnormalities. In total, 141 patients were prospectively evaluated, 69 underwent ACL reconstruction using a standard high medial portal as view portal, and 72 where a CTP was used. Clinical evaluation, Kujala's score, patellar height, and magnetic resonance (MR) abnormalities were evaluated up to 1-year follow-up. Clinical complications were reported in 16 cases with no statistically significant differences between the two groups. The group 2 had significantly more MR abnormalities (p = 0.048), but the differences in MR alterations do not have any clinical repercussion even in a sports-active population. No differences were found between the groups in Kujala's score, time to return to work, and sport or patellar height. The overall mean preoperative Caton-Deschamps Index decreased significantly (p = 0.034) postoperatively. Postoperative patellar height seems to slightly decrease after ACL reconstruction regardless of the kind of the portals used intraoperatively and the initial patellar height. Nevertheless, this change in patellar height does not influence the postoperative outcome. CTP used for ACL reconstruction does not lead to significative major clinical complications.
A study of the vibration isolation performance of a limited phononic crystal vibration isolator based on local resonance theory
Authors: Zhao Caiyou , Gao Xin , Wang Liuchong , Yi Qiang , Wang Ping
Published: October 2020

In this study, a limited phononic crystal vibration isolation (LPCVI) model is constructed based on a vibration isolator used in the field of rail transit, and analyses of the characteristics of the bandgap, the vibration isolation effect, and the vibrational energy transfer of the model are presented. In this paper, the Boltzmann integration theory and the Bloch theorem are used to establish a mathematical model that analyzes the band structure based on the viscoelastic damping of the system. Additionally, by comparing the practical finite periodic structure model and the conventional mass-spring-damping vibration isolation model, explicit forms of the vibration isolation coefficients of the models are derived. It is found that when the external excitation frequency is within the forbidden band range, the vibration isolation coefficient of the LPCVI system with a harmonic oscillator is much smaller than that of the vibration isolation system with a general mass-spring. Furthermore, the Newmark-β integration method is adopted to solve the vibration equation of the LPCVI model. The energy input, distribution, and output of the system are obtained when the energy is under excitation in the forbidden band and bandpass frequencies. It is found that the external excitation does both positive and negative works on the vibration isolation system within a certain period under the action of the central frequency excitation of the forbidden band; therefore, the energy cannot be input into the isolation system. This makes it possible to achieve effective vibration isolation at lower frequencies.
Region-of-interest micro-focus computed tomography based on an all-optical inverse Compton scattering source
Authors: Ma Yue , Hua Jianfei , Liu Dexiang , He Yunxiao , Zhang Tianliang , Chen Jiucheng , Yang Fan , Ning Xiaonan , Yang Zhongshan , Zhang Jie , Pai Chih-Hao , Gu Yuqiu , Lu Wei
Published: October 2020

Micro-focus computed tomography (CT), which allows the hyperfine structure within objects to be reconstructed, is a powerful nondestructive testing tool in many fields. However, current x-ray sources for micro-focus CT are typically limited by their relatively low photon energy and low flux. An all-optical inverse Compton scattering source (AOCS) based on laser wakefield acceleration can generate intense quasi-monoenergetic x/gamma-ray pulses in the kilo- to megaelectronvolt range with micrometer-level source size, and its potential application for micro-focus CT has become very attractive in recent years because of the rapid progress made in laser wakefield acceleration. Reported here is a successful experimental demonstration of high-fidelity micro-focus CT using an AOCS (∼70 keV) by imaging and reconstructing a test object with complex inner structures. A region-of-interest CT method is adopted to utilize the relatively small field of view of the AOCS to ensure high spatial resolution. This demonstration of AOCS-based region-of-interest micro-focus CT is a key step toward its application in the field of hyperfine nondestructive testing.
Rare events and first passage time statistics from the energy landscape
Authors: Swinburne Thomas D. , Kannan Deepti , Sharpe Daniel J. , Wales David J.
Published: October 2020

We analyze the probability distribution of rare first passage times corresponding to transitions between product and reactant states in a kinetic transition network. The mean first passage times and the corresponding rate constants are analyzed in detail for two model landscapes and the double funnel landscape corresponding to an atomic cluster. Evaluation schemes based on eigendecomposition and kinetic path sampling, which both allow access to the first passage time distribution, are benchmarked against mean first passage times calculated using graph transformation. Numerical precision issues severely limit the useful temperature range for eigendecomposition, but kinetic path sampling is capable of extending the first passage time analysis to lower temperatures, where the kinetics of interest constitute rare events. We then investigate the influence of free energy based state regrouping schemes for the underlying network. Alternative formulations of the effective transition rates for a given regrouping are compared in detail to determine their numerical stability and capability to reproduce the true kinetics, including recent coarse-graining approaches that preserve occupancy cross correlation functions. We find that appropriate regrouping of states under the simplest local equilibrium approximation can provide reduced transition networks with useful accuracy at somewhat lower temperatures. Finally, a method is provided to systematically interpolate between the local equilibrium approximation and exact intergroup dynamics. Spectral analysis is applied to each grouping of states, employing a moment-based mode selection criterion to produce a reduced state space, which does not require any spectral gap to exist, but reduces to gap-based coarse graining as a special case. Implementations of the developed methods are freely available online.
Electrical compensation and cation vacancies in Al rich Si-doped AlGaN
Authors: Prozheev I. , Mehnke F. , Wernicke T. , Kneissl M. , Tuomisto F.
Published: October 2020

We report positron annihilation results on vacancy defects in Si-doped Al0.90Ga0.10N alloys grown by metalorganic vapor phase epitaxy. By combining room temperature and temperature-dependent Doppler broadening measurements, we identify negatively charged in-grown cation vacancies in the concentration range from below 1×1016 cm−3 to 2×1018 cm−3 in samples with a high C content, strongly correlated with the Si doping level in the samples ranging from 1×1017 cm−3 to 7×1018 cm−3. On the other hand, we find predominantly neutral cation vacancies with concentrations above 5×1018 cm−3 in samples with a low C content. The cation vacancies are important as compensating centers only in material with a high C content at high Si doping levels.
Effects of strain on defect-graphene superlattices
Authors: Barone Victor T. , Tuttle Blair R.
Published: October 2020

Defects in graphene provide both a challenge and an opportunity for scientists and engineers. Here, we report first-principles calculations of the mechanical, electronic, and magnetic properties of defect-graphene superlattices involving periodic arrays of vacancy and ring disorder defects. Using the relationship between energy and strain, we quantify the elastic moduli for these defect-graphene superlattices. Compared to pure graphene, the di-vacancy defect superlattice shows the largest change in lattice vectors but only a modest deviation in mechanical properties. Young’s modulus for the Stone–Thrower–Wales defect superlattice is found to be dramatically lower than for pure graphene. Strain has only a modest effect on the electronic structure of the defect-graphene superlattices, except for single vacancies in graphene, which display a strain-induced Jahn–Teller bond reconfiguration resulting in a discontinuous magnetic response. The effects detailed here may be exploited for device applications employing defect-graphene superlattices.
Dynamics of periodically forced finite N-oscillators, with implications for the social synchronization of animal rest–activity rhythms
Authors: Li Ying , Schwartz William J. , Indic Premananda
Published: October 2020

The possible mechanisms for the synchronization of rest–activity rhythms of individual animals living in groups is a relatively understudied question; synchronized rhythms could occur by entrainment of individuals to a common external force and/or by social synchronization between individuals. To gain insight into this question, we explored the synchronization dynamics of populations of globally coupled Kuramoto oscillators and analyzed the effects of a finite oscillator number (N) and the variable strengths of their periodic forcing (F) and mutual coupling (K). We found that increasing N promotes entrainment to a decreasing value of F, but that F could not be reduced below a certain level determined by the number of oscillators and the distribution width of their intrinsic frequencies. Our analysis prompts some simple predictions of ecologically optimal animal group sizes under differing natural conditions.
Nanopipettes—The past and the present
Authors: Stanley John , Pourmand Nader
Published: October 2020

Nanopipettes, characterized by nanoscale sized pores and simple fabrication techniques, are of increasing scientific interest due to their application in a variety of fields, including analytical chemistry, nanophysiology, molecular diagnostics, and cellular biology. Nanopipettes have been extensively used for the development of electrochemical biosensors, as they offer the combined advantage of nanoscale dimensions and the selectivity and sensitivity of conventional solid-state biosensors. Over the years, with advances in technology and the expansion of research interests, functionalized nanopipettes have been successfully employed for performing real-time quantitative measurement of changes within a single cell. They have also been routinely used to aspirate/inject attoliter to picoliter volumes at intracellular levels and have become the “go-to” tools for cutting-edge research in molecular and cell biology. The use of nanopipettes as probes for imaging soft materials through scanning probe microscope (SPM) techniques such as scanning electrochemical microscopy and scanning ion-conductance microscopy has been widely explored. Advances in both the technical and theoretical aspects of nanopipette technology have a profound impact on early diagnosis and treatment of various diseases including cancer, diabetes, and Alzheimer’s. In this review, we provide insights into the fabrication, morphological, and electrochemical characterization of the nanopipette and comprehensively discuss the various applications available in the literature of nanopipettes as sensing probes, monitoring probes for single cells, and SPMs.
Fabrication of low aspect ratio three-element Boersch phase shifters for voltage-controlled three electron beam interference
Authors: Thakkar Pooja , Guzenko Vitaliy A. , Lu Peng-Han , Dunin-Borkowski Rafal E. , Abrahams Jan Pieter , Tsujino Soichiro
Published: October 2020

A Boersch phase plate can shift the phase of electrons proportionally to the applied electrical potential, thereby allowing for in situ control of the electron phase shift. A device comprising multiple Boersch phase shifter elements will be able to modulate the wavefront of a coherent electron beam and control electron interference. Recently, fabrication of single and 2 × 2 element Boersch phase shifter devices by focused ion beam milling has been reported. Realization of a large-scale Boersch phase shifter array would demand further developments in the device design and the fabrication strategy, e.g., using lithographic processes. In the present work, we develop a fabrication method utilizing the state-of-the-art electron beam lithography and reactive ion etching processes, a combination that is widely used for high-throughput and large-scale micro- and nanofabrication of electronic and photonic devices. Using the developed method, we fabricated a three-element phase shifter device with a metal–insulator–metal structure with 100-nm-thick ring electrodes and tested its electron transmission characteristics in a transmission electron microscope with a beam energy of 200 keV. We observed voltage-controlled evolution of electron interference, demonstrating the voltage-controlled electron phase shift using the fabricated device with a phase shift of π rad per 1 V. We analyze the experimental results in comparison with a three-dimensional electrostatic simulation. Furthermore, we discuss the possible improvements in terms of beam deflection and crosstalk between phase shifter elements in a five-layer device structure.
Fusion reactor with electrodynamic stabilization
Authors: Balaci Octavian
Published: October 2020

Magnetic confinement of thermonuclear plasma can be significantly improved by using the reaction of an electrical conductive wall in combination with the AC driving of the plasma current. In this way, magnetic fields can be confined in some well-defined space and with the plasma itself. In addition, many plasma instabilities are suppressed or reduced.
Heat transfer performance of a storage system of molten-salt thermocline-packed bed
Authors: Yang Xiaoping , Cai Zhuodi , Zuo Yuanzhi
Published: October 2020

A packed bed is a good heat-storage method because of its simple structure, low cost, and good heat-transfer performance. Packed beds generally have a thermocline temperature distribution. This study analyzes a molten-salt thermocline storage system packed with a sensible heat material based on simulation and experimental research. The relationships between heat transfer and the characteristic parameters of the filling material, charging time, and initial conditions are obtained. Investigation results show that the thickness of the thermocline layer reduces with the increase in volume heat capacity but increases with time. The equivalent diameter of particles almost has zero effect on the thermocline thickness, and porosity has an indirect impact on the thickness of the thermocline layer but influences the movement speed of the thermocline. The maximum temperature difference between the fluid and solid decreases, but the range of temperature differences increases with time.
Nonlinear fluorescence spectroscopy of layered perovskite quantum wells
Authors: Ouyang Zhenyu , Zhou Ninghao , Hu Jun , Williams Olivia F. , Yan Liang , You Wei , Moran Andrew M.
Published: October 2020

Interest in layered organohalide perovskites is motivated by their potential for use in optoelectronic devices. In these systems, the smallest and largest quantum wells are primarily concentrated near the glass and air interfaces of a film, thereby establishing a gradient in the average values of the bandgaps. It has been suggested that this layered architecture promotes the funneling of electronic excitations through space in a manner similar to light-harvesting processes in photosynthetic antennae. Whereas energy and charge transfer are difficult to distinguish by conventional transient absorption techniques, it has recently been shown that these competing relaxation mechanisms may be separately targeted with nonlinear fluorescence (NLFL) and photocurrent “action spectroscopies.” Here, we present perturbative rate functions to describe NLFL experiments conducted on layered perovskite systems. The formulas reproduce the patterns of resonances observed in experimental measurements and show how signatures of energy transfer manifest in two-dimensional spectra. Overall, this work suggests that NLFL spectroscopy may be used to fully reveal the trajectories of electronic excitations by correlating ultrafast energy transfer pathways to fluorescence emission from the thickest quantum wells.
Hydrogen nuclear mean kinetic energy in water down the Mariana Trench: Competition of pressure and salinity
Authors: Bocedi Alessio , Romanelli Giovanni , Andreani Carla , Senesi Roberto
Published: October 2020

The Mariana Trench is one of the most famous and extreme environments on our planet. We report experimental values of the hydrogen nuclear mean kinetic energy in water samples at the same physical and chemical conditions than in the Challenger Deep within the Mariana Trench: a pressure of 1092 bars, a temperature of 1 °C, and a salinity of 35 g of salt per kg of water. Results were obtained by deep inelastic neutron scattering at the VESUVIO spectrometer at ISIS. We find that the effect of pressure is to increase the hydrogen nuclear mean kinetic energy with respect to ambient conditions, while ions in the solution have the opposite effect. These results confirm the recent state-of-the-art simulations of the nuclear hydrogen dynamics in water. The changes in the nuclear mean kinetic energy likely correspond to different isotopic fractionation values in the Challenger Deep compared to standard sea water.
Time-resolved imaging of an operating hard-disk-drive write head using nano-beam x-ray magnetic circular dichroism
Authors: Suto Hirofumi , Kikitsu Akira , Kotani Yoshinori , Maeda Tomoyuki , Toyoki Kentaro , Osawa Hitoshi , Kikuchi Nobuaki , Okamoto Satoshi , Nakamura Tetsuya
Published: October 2020

We studied the dynamic magnetization behavior of a hard-disk-drive (HDD) write head by using nano-beam x-ray magnetic circular dichroism (XMCD). The write head was operated by applying a square-wave write current with a frequency of 211.9 MHz to the coil of the write head, which was in synchronization with the fivefold frequency of the x-ray pulses. Snapshot images of the magnetization on the air-bearing surface of the write head were obtained with spatial and time resolutions of 100 nm and 50 ps, respectively, and temporal changes in the magnetization of the main pole and the shield were observed. When a square-wave write current with a transition time of 0.2 ns was applied, the magnetization reversal of the main pole was completed in 0.7 ns, and this reversal time was determined by the dynamic property of the write head. During the main pole reversal, the shield area showed spatially non-uniform magnetization patterns, and its response was slower than that of the main pole. These results show that the XMCD measurement setup developed in this study is a powerful tool for understanding the dynamic behavior of an HDD write head and contributes to the development of higher capacity HDDs.
Monolayer 1T-LaN2: Dirac spin-gapless semiconductor of p-state and Chern insulator with a high Chern number
Authors: Li Linyang , Kong Xiangru , Chen Xin , Li Jia , Sanyal Biplab , Peeters François M.
Published: October 2020

Two-dimensional transition-metal dinitrides have attracted considerable attention in recent years due to their rich magnetic properties. Here, we focus on rare-earth-metal elements and propose a monolayer of lanthanum dinitride with a 1T structural phase, 1T-LaN2. Using first-principles calculations, we systematically investigated the structure, stability, magnetism, and band structure of this material. It is a flexible and stable monolayer exhibiting a low lattice thermal conductivity, which is promising for future thermoelectric devices. The monolayer shows the ferromagnetic ground state with a spin-polarized band structure. Two linear spin-polarized bands cross at the Fermi level forming a Dirac point, which is formed by the p atomic orbitals of the N atoms, indicating that monolayer 1T-LaN2 is a Dirac spin-gapless semiconductor of p-state. When the spin–orbit coupling is taken into account, a large nontrivial indirect bandgap (86/354 meV) can be opened at the Dirac point, and three chiral edge states are obtained, corresponding to a high Chern number of C = 3, implying that monolayer 1T-LaN2 is a Chern insulator. Importantly, this kind of band structure is expected to occur in more monolayers of rare-earth-metal dinitride with a 1T structural phase.
Application of the exact regularized point particle method (ERPP) to bubble laden turbulent shear flows in the two-way coupling regime
Authors: Motta F. , Battista F. , Gualtieri P.
Published: October 2020

Direct numerical simulations of a bubbly laden homogeneous shear flow have been carried out using the exact regularized point particle method as the inter-phase momentum coupling approach. The aim of this study consists in addressing the modulation of shear turbulence and the bubble clustering geometry in the presence of different inter-phase momentum coupling conditions. Suspensions with different combinations of the void fraction and Kolmogorov-based Stokes number, in the dilute regime, have been addressed. Bubbles suppress the turbulent kinetic energy and turbulent dissipation as well. Turbulent modulation occurs via the direct change of the Reynolds shear stress. In fact, the bubble energy source is proved to be negligible in the scale-by-scale turbulent energy budget. The bubble clustering, in agreement with the literature, occurs in the form of thin elongated structures. The clusters are aligned with the principal strain direction of the mean flow, as usual in shear flows. The bubble clustering and turbulent modification are strictly related: both increase with the Stokes number and are independent of the void fraction. The data show that the turbulent modification is disadvantaged when the bubble distribution is homogeneous (i.e., small Stokes number). Finally, the small-scale bubble clustering is slightly reduced by two-way coupling effects even though the clustering anisotropy still persists at small scales as it occurs for inertial particles.
Field free magnetization switching in perpendicularly magnetized Pt/Co/FeNi/Ta structure by spin orbit torque
Authors: Chang Meixia , Yun Jijun , Zhai Yongbo , Cui Baoshan , Zuo Yalu , Yu Guoqiang , Xi Li
Published: October 2020

Spin orbit torque-driven magnetization switching in perpendicularly magnetized thin film relies on an extra in-plane magnetic field to break the in-plane magnetic symmetry, which is an obstacle for the integration of spin–orbit torque-based spintronic devices. Here, we propose a simple method to realize the field-free spin–orbit torque-driven magnetization switching by exploiting a tilted magnetic anisotropy, which is caused by the direct coupling of two ferromagnetic layers in the Pt/Co/FeNi/Ta structure. When preparing the sample, a 1000 Oe in-plane magnetic field was applied to ensure the magnetic moment deviating a small angle from the out-of-plane direction to this in-plane field direction. We experimentally demonstrate the deterministic field-free magnetization switching in Pt/Co/FeNi/Ta by the field-like spin–orbit torques when the electric current is applied perpendicular to this in-plane field direction. The switching performance is slightly degraded with the critical switching current density and thermal stability factor, respectively, reaching 6.4 × 106 A/cm2 and 25 due to the slightly decreased spin–orbit torque efficiency and perpendicular magnetic anisotropy with introducing the FeNi layers. Our work paves the way for realizing the field-free magnetization switching by spin–orbit torques.
Assessment of foliar-applied phosphorus fertiliser formulations to enhance phosphorus nutrition and grain production in wheat
Authors: McBeath Therese M. , Facelli Evelina , Peirce Courtney A. E. , Arachchige Viran Kathri , McLaughlin Michael J.
Published: October 2020

The ability to utilise foliar-applied phosphorus (P) as a strategy to increase the P status and yield of grain crops grown in dryland regions with variable climates is attractive. Several P formulations with varying pH, accompanying cations and adjuvants were tested for their effectiveness as foliar fertilisers for wheat (Triticum aestivum L.) plants, first under controlled and then under field conditions. Experiments under controlled conditions suggested that several formulations with specific chemistries offered promise with respect to wheat fertiliser-P recovery and biomass responses. These formulations were then evaluated in two field experiments, and although wheat grown at the sites showed substantive responses to soil-applied P, there was no significant grain-yield response to foliar-applied P. Following the limited responses to foliar-applied fertiliser in the field, we used an isotopic dilution technique to test the hypothesis that the variation in responses of wheat to foliar addition of P could be explained by a mechanism of substitution, whereby root P uptake is downregulated when P is taken up through the leaves, but this was proven not to be the case. We conclude that foliar P application cannot be used as a tactical fertiliser application to boost grain yield of wheat in dryland regions.
Nitrogen-fertiliser application effects on cotton lint percentage, seed size, and seed oil and protein concentrations
Authors: Rochester Ian J. , Constable G. A.
Published: October 2020

In order to develop a better understanding of some yield components, the response of three modern cotton (Gossypium hirsutum L.) cultivars to increasing nitrogen (N) fertiliser application was assessed for lint percentage (LP) and seed weight, as well as seed protein and oil concentrations. Application of N fertiliser led to decreased LP in all three cultivars (by 1.5 percentage points), even if the N-fertiliser rate was above the optimum rate. There was a strong negative correlation between LP and seed mass because seed mass is a component of LP. Seed protein concentration increased, and seed oil concentration decreased, with increasing N fertiliser application. Seed germination was improved in seeds with higher oil concentration; therefore, seed produced with high N fertiliser had reduced seed vigour. It was concluded that little scope exists for further lint-yield increase via LP. For cultivars with small seeds, an integrated system across seed production and crop agronomy can achieve satisfactory seed vigour in the field while also achieving high commercial yields. Future improvements in yield will come from alternative and more complex yield components such as growth habit.
Melatonin regulates ATP content and fertilising capacity of Onychostoma macrolepis spermatozoa by inhibiting ROS accumulation during semen storage in vitro
Authors: Yang Jinmeng , Dong Daqian , Peng Guofan , Sun Qingfang , Yang Chenhao , Gao Yao , Ji Hong , Dong Wuzi
Published: October 2020

Melatonin (MLT) is an efficient antioxidant that protects spermatozoa against damages caused by oxidative stress. In this study, to maintain good function of Onychostoma macrolepis spermatozoa during semen preservation invitro at 4°C, different concentrations of MLT (0.5, 1 and 2μM) were added to the semen. After storage (0, 24, 48 and 72h), 1μM MLT in semen markedly improved sperm quality, as reflected by better plasma membrane integrity, the relative steady level of reactive oxygen species (ROS) and slower rate of decrease in mitochondrial membrane potential. Activated spermatozoa in semen with 1μM MLT had higher kinematic performance (i.e. percentage of motile and progressive spermatozoa and the beat cross frequency; P<0.05) and longer duration of sperm motility (P<0.05) compared with spermatozoa in semen withother MLT concentrations. Furthermore, 1μM MLT maintained higher ATP concentrations in spermatozoa during semen storage and significantly improved the fertilising capacity of spermatozoa after 72h semen storage compared with the other MLT concentrations. To expand wild resources of O. macrolepis, 1μM MLT can be used as a semen additive to maintain better sperm function and enhance sperm fertilising capacity in artificial insemination (AI).
Flooding-induced mortality of loggerhead sea turtle eggs
Authors: Limpus Colin J. , Miller Jeffrey D. , Pfaller Joseph B.
Published: October 2020

Abstract
ContextMarine turtle eggs incubate in dynamic beaches, where they are vulnerable to both saltwater and freshwater flooding. Understanding the capacity for marine turtle eggs to tolerate flooding will aid management efforts to predict and mitigate the impacts of climate change, including sea-level rise and increases in coastal flooding.
AimsEvaluate the interactive effects of flooding duration and incubation stage on the hatching success of loggerhead turtle (Caretta caretta) eggs.
MethodsGroups of 20 eggs from multiple clutches were incubated in plastic containers in a beach hatchery. Eggs at six stages of incubation (0, 1, 2, 4, 6 and 7 weeks post-oviposition) were excavated from the hatchery and exposed to saltwater or freshwater flooding for seven durations of time (0, 1, 2, 3, 6, 24 or 48h). Containers of eggs were either submerged in a bucket of water or left outside of the bucket (control; no flooding) for their designated duration, allowed to drain, then reburied in the hatchery. Following hatchling emergence, the hatching success of each group of eggs was evaluated.
Key resultsFreshly laid eggs and eggs on the verge of hatching exposed to any flooding and all eggs exposed to extended periods of flooding (24 and 48h) suffered complete mortality. Eggs at 20–80% development exposed to short periods of flooding (1–6h) maintained high hatching success that was statistically equivalent to control eggs, while eggs at <20% and >80% development exhibited significant decreases in hatching success.
ConclusionsMarine turtle eggs in the middle of incubation can tolerate saltwater and freshwater flooding for up to 6h. Outside of this period or when flooding is longer, disruption of gas concentrations and osmotic gradients in the egg chamber can lead to embryonic mortality. These findings have reinforced concerns regarding the capacity for marine turtle populations to continue to function as rising sea levels and increases in coastal flooding alter the hydrology of nesting beaches.
ImplicationsAs current and predicted climate change threatens the suitability of the incubation environment used by marine turtles, corrective actions to maximise hatching success need to be taken before the eggs are flooded.
Neddylation is critical to cortical development by regulating Wnt/β-catenin signaling
Authors: Zhang Lei , Jing Hongyang , Li Haiwen , Chen Wenbing , Luo Bin , Zhang Hongsheng , Dong Zhaoqi , Li Lei , Su Huabo , Xiong Wen-Cheng , Mei Lin
Published: October 2020

Significance

The neocortex is characterized by a six-layered structure that is critical to brain function. Cortical development requires proper generation and differentiation of neurons that migrate out from the ventricular zone to populate the cortex. This is regulated by Wnt/β-catenin signaling, which reduces gradually during cortical development. However, how the decreasing of Wnt/β-catenin signaling is regulated is largely unclear. We demonstrate that neddylation, a ubiquitylation-like protein posttranslational modification, targets β-catenin itself to inhibit Wnt/β-catenin signaling in the process. We also show that ablating Nae1, an obligative subunit of the E1 for neddylation, from cortical progenitor cells leads to similar phenotypes in β-catenin gain-of-function mice. This study reveals a previously unappreciated role of neddylation in regulating cortical lamination by targeting β-catenin signaling.
Cross-level sociodemographic homogeneity alters individual risk for completed suicide
Authors: Pescosolido Bernice A. , Lee Byungkyu , Kafadar Karen
Published: October 2020

Significance

Recent unexpected increases in US suicides reinforce calls for fresh approaches to understanding suicide risk. Theorizing the complexity of suicide risk and harmonizing existing large data sources, we find two distinct patterns. Having more similar others in a geographical context dampens suicide risk for non–native-born, unemployed, and widowed individuals. However, social similarity heightens suicide risk in counties with a larger share of some race/ethnic and marital status groups. Knowing how social contexts alter individual suicide risk suggests innovative research directions, and provides paths to craft personalized and tailored strategies for anti-suicide programs, policies, and treatment.
Evolved differences in energy metabolism and growth dictate the impacts of ocean acidification on abalone aquaculture
Authors: Swezey Daniel S. , Boles Sara E. , Aquilino Kristin M. , Stott Haley K. , Bush Doug , Whitehead Andrew , Rogers-Bennett Laura , Hill Tessa M. , Sanford Eric
Published: October 2020

Significance

The pH of the global ocean is decreasing due to the absorption of anthropogenically emitted CO
2
, causing ocean acidification (OA). OA negatively impacts marine shellfish and threatens the continuing economic viability of molluscan shellfish aquaculture, a global industry valued at more than 19 billion USD. We identify traits linked to growth and lipid regulation that contribute tolerance to OA in abalone aquaculture, with broader implications for adaptation efforts in other shellfish species. We also identify evolved heritable variation for physiological resilience to OA that may be exploited in commercial and restoration aquaculture breeding programs to offset the negative consequences of continuing climate change.
Comparative isotope ecology of western Amazonian rainforest mammals
Authors: Tejada Julia V. , Flynn John J. , Antoine Pierre-Olivier , Pacheco Victor , Salas-Gismondi Rodolfo , Cerling Thure E.
Published: October 2020

Significance

Closed-canopy rainforests are important for climate and ecology, yet identifying this ecosystem in the fossil record is challenging. An existing paradigm for identification of closed-canopy rainforests using fossil mammal carbon isotope data is the presence of highly negative δ
13
C
diet
values (<−31‰) in the herbivore community, as observed in modern equatorial African rainforest ecosystems. Our data from western Amazonian mammals, however, show that the absence of these values is not evidence for absence of closed-canopy rainforests. Our results also document that the proposed relationship between carbon isotope spacing variables and traditional dietary ecological classifications is not straightforward, and that better characterizations of the mixture of nutrients in animal diets are necessary to fully understand diet-tissue isotopic fractionation patterns.
Peak grain forecasts for the US High Plains amid withering waters
Authors: Mrad Assaad , Katul Gabriel G. , Levia Delphis F. , Guswa Andrew J. , Boyer Elizabeth W. , Bruen Michael , Carlyle-Moses Darryl E. , Coyte Rachel , Creed Irena F. , van de Giesen Nick , Grasso Domenico , Hannah David M. , Hudson Janice E. , Humphrey Vincent , Iida Shin’ichi , Jackson Robert B. , Kumagai Tomo’omi , Llorens Pilar , Michalzik Beate , Nanko Kazuki , Peters Catherine A. , Selker John S. , Tetzlaff Doerthe , Zalewski Maciej , Scanlon Bridget R.
Published: October 2020

Significance

Rapid groundwater depletion represents a significant threat to food and water security because groundwater supplies more than 20% of global water use, especially for crop irrigation. A large swath of the US High Plains, which produces more than 50 million tons of grain yearly, depends on the Ogallala aquifer for more than 90% of its irrigation needs. A predator–prey-type model serves as a minimalist representation of groundwater use–crop production dynamics. It explains and predicts reductions in groundwater withdrawal on three High Plains states and subsequent declines in irrigated crop production. The model shows how recharge rates and the adoption of irrigation technologies control these trends. It also provides a general framework for assessing groundwater-based irrigation sustainability.
The transcription factor C/EBPβ orchestrates dendritic cell maturation and functionality under homeostatic and malignant conditions
Authors: Scholz Florian , Grau Michael , Menzel Lutz , Graband Annika , Zapukhlyak Myroslav , Leutz Achim , Janz Martin , Lenz Georg , Rehm Armin , Höpken Uta E.
Published: October 2020

Significance

Complex transcription factor networks regulate the development, maturation, and lineage commitment of dendritic cell (DC) subsets. Here, we demonstrate a previously unexpected role of the transcription factor C/EBPβ in murine DC maturation and immunogenic functionality under homeostatic and lymphoma-transformed conditions. Regulated expression of functional C/EBPβ isoforms enables a controlled maturation of DCs. In contrast, the presence of lymphoma cells leads to an up-regulation of C/EBPβ in DCs which transforms them into an immature and protumorigenic subtype. This study also shows that inhibition of the C/EBPβ/mTOR signaling axis abrogates the protumorigenic function of human DCs, suggesting that inhibitors regulating C/EBPβ activity can be used for blocking tumor-promoting functions of DCs in the treatment of hematological neoplasms.