bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Quiet and Noise on P300 Response in Individuals with Auditory Neuropathy Spectrum Disorder
Authors: Apeksha Kumari , Kumar Ajith U.
Published: March 2020

Introduction Auditory neuropathy spectrum disorder (ANSD) is a clinical condition in which individuals have normal cochlear responses and abnormal neural responses. There is a lack of evidence in the literature regarding the neural discrimination skill in individuals with ANSD, especially when the signal is presented in the presence of noise.

Objectives The present study was performed with the aim to investigate auditory discrimination skill, in quiet and in the presence of noise, in individuals with ANSD and to compare the findings with normal-hearing individuals.

Methods A total of 30 individuals with normal hearing sensitivity and 30 individuals with ANSD in the age range of 15 to 55 years old, with the mean age of 27.86 years old, were the participants. P300 response was recorded from both groups using syllable pairs /ba/-/da/ in oddball paradigm and the syllable /da/ in repetitive paradigm in quiet and at +10 dB signal-to-noise ratio (SNR).

Results There was significant prolongation in latency and reaction time, and reduction in amplitude of P300 response and sensitivity in both groups with the addition of noise. The topographic pattern analysis showed activation of the central-parietal-occipital region of the brain in individuals with ANSD, whereas activation of the central-parietal region was observed in individuals with normal hearing. The activation was more diffused in individuals with ANSD compared with that of individuals with normal hearing.

Conclusion The individuals with ANSD showed a significantly more adverse effect of noise on the neural discrimination skill than the normal counterpart.
Chordoid Meningioma: Literature Review
Authors: Massella Junior Carlos Roberto , de Morais Marcus Vinicius , Figueiredo Rafael Pontes , Morales Andrezza Garcia , Porto de Melo Paulo Mácio
Published: March 2020

Chordoid meningiomas (CMs) are a rare subgroup of tumors, accounting for ∼ 0.5% of all meningiomas. Chordoid meningioma tumors correspond to World Health Organization (WHO) Grade II lesions and behave aggressively, with an increased likelihood of recurrence. There are few genetic studies about CMs, but we understand that there is deletion at many chromosomal loci. Histologically, CMs are characterized by strands and cords of meningothelial cells arranged in a mucinous stroma. Morphologically, it can mimic other chondroid and myxoid tumors within the brain and its vicinity, thus posing a diagnostic challenge. Chordoid meningiomas have an aggressive clinical course and a propensity to recur compared with classical meningiomas. The goal of the treatment is surgery, with total resection of the tumor; however, due to its high degree of recurrence, radiotherapy is often necessary as an adjuvant treatment.
Angiomiolipoma renal con invasión de vena renal y vena cava inferior. Presentación de un caso y revisión de la literatura
Authors: Gutiérrez-Zurimendi Garazi , Albisu-Tristán Andoni , Padilla-Nieva Jesús , Acha-Pérez Marcos , Urresola-Olabarrieta Aranzazu , de Casasola-Rodríguez Gonzalo García , Arruza-Echevarría Antonio
Published: March 2020

Introducción El angiomiolipoma es un tumor benigno cuya presentación con invasión del seno renal y formación de trombo venoso tumoral es muy infrecuente, habiéndose descrito aproximadamente 50 casos desde que en 1982 Kutcher describiera el primero.

Reporte de caso Presentamos un caso angiomiolipoma renal con afectación venosa diagnosticado mediante TAC a partir del hallazgo de trombo venoso en ecografía y resonancia en una paciente de 43 años embarazada y asintomática que presentó elevación de transminasas en una analítica. Ante la posibilidad de que se tratara de una variante epitelioide y/o clásica con potencial de malignización, se decidió tratamiento mediante nefrectomía y trombectomía abierta, sin incidencias intra ni postoperatorias. La paciente se encuentra asintomática tras 6 meses de seguimiento. La histología fue compatible con angiomiolipoma clásico con trombo venoso.

Conclusión La invasión de vena renal por un angiomiolipoma es extremadamente rara. Aunque infrecuente, habría que considerar la posibilidad de malignización para no demorar su tratamiento.
The Impact of Changes to an Electronic Admission Order Set on Prescribing and Clinical Outcomes in the Intensive Care Unit
Authors: Muniga Ellen T. , Walroth Todd A. , Washburn Natalie C.
Published: March 2020

Background Implementation of disease-specific order sets has improved compliance with standards of care for a variety of diseases. Evidence of the impact admission order sets can have on care is limited.

Objective The main purpose of this article is to evaluate the impact of changes made to an electronic critical care admission order set on provider prescribing patterns and clinical outcomes.

Methods A retrospective, observational before-and-after exploratory study was performed on adult patients admitted to the medical intensive care unit using the Inpatient Critical Care Admission Order Set. The primary outcome measure was the percentage change in the number of orders for scheduled acetaminophen, a histamine-2 receptor antagonist (H2RA), and lactated ringers at admission before implementation of the revised order set compared with after implementation. Secondary outcomes assessed clinical impact of changes made to the order set.

Results The addition of a different dosing strategy for a medication already available on the order set (scheduled acetaminophen vs. as needed acetaminophen) had no impact on physician prescribing (0 vs. 0%, p = 1.000). The addition of a new medication class (an H2RA) to the order set significantly increased the number of patients prescribed an H2RA for stress ulcer prophylaxis (0 vs. 20%, p < 0.001). Rearranging the list of maintenance intravenous fluids to make lactated ringers the first fluid option in place of normal saline significantly decreased the number of orders for lactated ringers (17 vs. 4%, p = 0.005). The order set changes had no significant impact on clinical outcomes such as incidence of transaminitis, gastrointestinal bleed, and acute kidney injury.

Conclusion Making changes to an admission order set can impact provider prescribing patterns. The type of change made to the order set, in addition to the specific medication changed, may have an effect on how influential the changes are on prescribing patterns.
The Value of Simulation in Interventional Radiology
Authors: Barnett Christopher J. , Pua Bradley B.
Published: March 2020

Medicine has increasingly incorporated simulation training amidst improving simulation technologies and evolving educational perspectives. This article examines the broad concept of simulation in medicine to focus, in particular, on its multifaceted value for providers and patients within the field of interventional radiology. Simulation technology ranges in degrees of fidelity, with new advancements notably in high-fidelity endovascular simulation, as well as in augmented and virtual reality. Current evidence on the validity of simulation within interventional radiology is promising, spanning training, credentialing, preprocedural planning, and team-building applications.
Correlation of clusters: Partially truncated correlation functions and their decay
Authors: Dorlas T. C. , Rebenko A. L. , Savoie B.
Published: March 2020

In this article, we investigate partially truncated correlation functions (PTCF) of infinite continuous systems of classical point particles with pair interaction. We derive Kirkwood–Salsburg-type equations for the PTCF and write the solutions of these equations as a sum of contributions labeled by certain forest graphs, the connected components of which are tree graphs. We generalize the method developed by Minlos and Poghosyan [Theor. Math. Phys. 31, 408 (1977)] in the case of truncated correlations. These solutions make it possible to derive strong cluster properties for PTCF, which were obtained earlier for lattice spin systems.
Monitoring driver health status in real time
Authors: Hamza Cherif Fayssal , Hamza Cherif Lotfi , Benabdellah Mohammed , Nassar Georges
Published: March 2020

Nowadays, surveillance systems have evolved significantly; hence, in order to meet the specific needs of the health sector and to monitor the patients’ health conditions, intelligent systems have been proposed. These innovations represent a primordial role in road safety, which reduce the risk of traffic accidents. This paper describes an intelligent system design for remote monitoring (tele-monitoring) of a driver’s health condition in real time. The measurement using new hardware and software devices is made possible through the contact between the driver contact and an intelligent steering wheel, which is coupled either to an integrated monitor or to a bluetooth link with a local Android smartphone. The driver’s heart rate is calculated through the continuous collection of the electrocardiographic signal as well as the blood oxygen saturation SpO2 by using the photoplethysmographic technique. Consequently, it is necessary to monitor the two vital functions of the driver, cardiac and respiratory activity. This information is transmitted to a remote tele-vigilance center in the case of abnormalities in these functions under the transmission control protocol/internet protocol involving a 4G/3G connection. The application is associated with the system that triggers high and low alarms locally and remotely in the events of tachycardia, bradycardia, or cardiac arrhythmia. Furthermore, another alarm is also triggered in the event of respiratory decompensation.
Structural, magnetic, and dielectric properties of charge-order phases in manganite La(Ca0.8Sr0.2)2Mn2O7
Authors: Zhang J. H. , Zheng S. H. , Tang Y. S. , Li Y. Q. , Zhou G. Z. , Chen P. Z. , Lin L. , Yan Z. B. , Jiang X. P. , Liu J.-M.
Published: March 2020

Charge-ordered layered manganites ReA2Mn2O7 (Re = rare-earth species and A = Ca, Sr, Ba, etc.) are believed to offer a number of fascinating electronic and magnetic properties, including the long-time claimed but not yet confirmed ferroelectricity associated with charge-ordering. Experimental observations of the charge-order induced transport and electrically polar behaviors have been insufficient. In this work, we synthesize the La(Ca0.8Sr0.2)2Mn2O7 (LCSMO) single crystal and investigate its structural, magnetic, and dielectric properties. It is revealed that LCSMO undergoes two consecutive charge-ordering transitions upon decreasing temperature T before entering an antiferromagnetic state in the low-T range. The first charge-order transition occurs at temperature TCO1 ∼ 314 K from the high-T paramagnetic state. This charge-order state (CO1 state) is transferred into another charge-order state (CO2 state) by a sequence starting from ∼290 K, and the resultant CO2 state is dynamic and polar-like. The dynamic behaviors of this polar-like CO2 state is confirmed by the remarkable dielectric relaxation associated with this state. The present work provides a connection between the charge-ordering and electrically polar response in LCSMO, while ferroelectricity remains yet to be an issue.
Material coherence from trajectories via Burau eigenanalysis of braids
Authors: Yeung Melissa , Cohen-Steiner David , Desbrun Mathieu
Published: March 2020

In this paper, we provide a numerical tool to study a material’s coherence from a set of 2D Lagrangian trajectories sampling a dynamical system, i.e., from the motion of passive tracers. We show that eigenvectors of the Burau representation of a topological braid derived from the trajectories have levelsets corresponding to components of the Nielsen–Thurston decomposition of the dynamical system. One can thus detect and identify clusters of space–time trajectories corresponding to coherent regions of the dynamical system by solving an eigenvalue problem. Unlike previous methods, the scalable computational complexity of our braid-based approach allows the analysis of large amounts of trajectories.
Reactive molecular dynamics research on influences of water on aging characteristics of PMIA insulation paper
Authors: Wang Lihan , Yin Fei , Shen Yin , Tang Chao
Published: March 2020

The diffusion of moisture in the meta-aramid fiber (PMIA) oil-paper insulation system and the thermal decomposition of PMIA insulation paper in different moisture contents were studied via molecular dynamics simulations. The results showed that the PMIA insulation paper had a stronger ability to absorb water molecules than the insulating oil; therefore, water molecules in the insulating oil diffuse to the insulation paper, which further affects the thermal decomposition of the PMIA insulation paper. The activation energy of the water-bearing composite model was 129.96 kJ/mol, which was 5.5% lower than that of the pure PMIA (137.61 kJ/mol). It indicated that moisture could promote PMIA decomposition. The micromechanism of the enhanced thermal decomposition of PMIA with moisture contents could be described as follows: The O–H bond of the water can easily break to generate H atoms and hydroxyl radicals (•OH). The strong activity of H atoms allows it to easily combine with the ammonia base at the end of PMIA to generate NH3. Additionally, the free •OH radical can easily combine with the amido and carbonyl bonds at two ends of PMIA, undergo an oxidation reaction, and generate an oxhydryl. Therefore, it can reduce the chemical stability of the PMIA chain and further drive thermal decomposition. Statistical data on fragments generated by the thermal decomposition of the water-bearing PMIA composite system show that the main products include H2, C/H/O-containing molecules, hydrocarbon molecules, N-bearing molecules, and free radicals.
Effect of encapsulation and additives doping on the thermophysical properties of erythritol for thermal energy storage
Authors: Wang Yi , Qin Ziyi , Zhang Ting , Zhang Zhengfei , Li Yong
Published: March 2020

We wished to improve the thermophysical properties and thermal stability of meso-erythritol (ET) for storage of thermal energy. Hence, capsules containing ET with polysiloxane (pSiO) shells were fabricated using ultraviolet-assisted in situ polymerization, and the effects of encapsulation and additives doping on the thermophysical properties of ET were studied. Differential scanning calorimetry showed that the heat-release performance of the composite (pSiO-C-A@ET) upon addition of 3.0 wt. % carboxymethylcellulose (CMC) and 9.0 wt. % nano-α-Al2O3 increased significantly from 64.1% to 89.0%, and the supercooling degree decreased dramatically from 89.5 °C to 17.0 °C, compared with that of pure ET. Spectroscopy (Fourier transform-infrared, x-ray diffraction) implied no change in the crystal structure of ET after encapsulation by pSiO shells. Addition of a nucleation agent (nano-α-Al2O3) and thickening agent (CMC) had no effect on the crystal structure of pSiO-C-A@ET. The thermal conductivity of pSiO@ET and pSiO-C-A@ET capsules increased by 6.2% and 20.0% compared with that of pure ET (0.65 W/m·K) at 25 °C, respectively. The thermal conductivity was enhanced noticeably by doping with nano-α-Al2O3. Results from accelerated thermal cycling suggested that pSiO@ET and pSiO-C-A@ET capsules exhibited good thermal stability and thermal durability. These data suggest that composite phase-change materials could be employed for applications involving storage of thermal energy.
An apparatus to measure elastic dispersion and attenuation using hydrostatic- and axial-stress oscillations under undrained conditions
Authors: Borgomano Jan V. M. , Gallagher Ariel , Sun Chao , Fortin Jérôme
Published: March 2020

An experimental apparatus is described for the investigation of frequency dispersion, and related attenuation, of fluid-saturated rocks under confining pressure and undrained boundary conditions. The forced-oscillation method is performed on cylindrical samples. The measurement of stress and strain under hydrostatic oscillations allows the dynamic bulk modulus to be inferred, while axial oscillations give access to dynamic Young’s modulus and Poisson’s ratio. We present calibration measurements for dispersion and attenuation on standard materials such as glass, plexiglass, and gypsum. Results show that for strain amplitudes below 10−5, robust measurements can be achieved up to 1 kHz and 1.3 Hz, respectively, for axial and hydrostatic oscillations. A new experimental design of the endplatens (sample holders) allows control of drained or undrained boundary conditions using microvalves. The microvalves were tested on a porous Vosgian sandstone. In addition, numerical modeling confirms that the resonances of the apparatus only affect frequencies above 1 kHz, with little sensitivity to the sample’s stiffness.
Splashing of fuel drops impacting on heated solid surfaces
Authors: Sreenivasan Akshay , Deivandren Sivakumar
Published: March 2020

Liquid drop impact on dry, solid surfaces has been studied to elucidate the role of control parameters, such as drop size, impact velocity, liquid properties, surface roughness, and wettability, on the mechanism of splashing phenomenon. It has been shown more recently that ambient gas plays a pivotal role in initiating the disintegration mechanisms leading to the ejection of secondary droplets from an impacting drop. Through systematic experiments, the role of target surface temperature in altering the morphology of a splash outcome of impacting fuel drops is investigated in the present work. It is observed that at elevated surface temperatures, the heated air film present very close to the hot surface suppresses splashing and consequently raises the splash threshold Weber number of the impacting fuel drop. For a given Weber number, the morphology of the impacting drop shifts from splashing to spreading with a rise in the surface temperature through an intermediate transition regime, characterized by the tendency of the liquid sheet to recontact the drop lamella without ejecting any secondary droplets. The experimental observations are compared with theoretical model predictions reported in the literature, and fair agreement is found in terms of both the observed splash suppression and the underlying mechanisms that govern the identified morphological regimes.
Time-resolved photoluminescence characterization of InGaAs/GaAs nano-ridges monolithically grown on 300 mm Si substrates
Authors: Shi Yuting , Kreuzer Lisa C. , Gerhardt Nils C. , Pantouvaki Marianna , Van Campenhout Joris , Baryshnikova Marina , Langer Robert , Van Thourhout Dries , Kunert Bernardette
Published: March 2020

The monolithic growth of III–V materials directly on Si substrates provides a promising integration approach for passive and active silicon photonic integrated circuits but still faces great challenges in crystal quality due to misfit defect formation. Nano-ridge engineering is a new approach that enables the integration of III–V based devices on trench-patterned Si substrates with very high crystal quality. Using selective area growth, the III–V material is deposited into narrow trenches to reduce the dislocation defect density by aspect ratio trapping. The growth is continued out of the trench pattern and a box-shaped III–V nano-ridge is engineered by adjusting the growth parameters. A flat (001) GaAs nano-ridge surface enables the epitaxial integration of a common InGaAs/GaAs multi-quantum-well (MQW) structure as an optical gain medium to build a laser diode. In this study, a clear correlation is found between the photoluminescence (PL) lifetime, extracted from time-resolved photoluminescence (TRPL) measurements, with the InGaAs/GaAs nano-ridge size and defect density, which are both predefined by the nano-ridge related pattern trench width. Through the addition of an InGaP passivation layer, a MQW PL lifetime of up to 800 ps and 1000 ps is measured when pumped at 900 nm (only QWs were excited) and 800 nm (QWs + barrier excited), respectively. The addition of a bottom carrier blocking layer further increases this lifetime to ∼2.5ns (pumped at 800 nm), which clearly demonstrates the high crystal quality of the nano-ridge material. These TRPL measurements not only deliver quick and valuable feedback about the III–V material quality but also provide an important understanding for the heterostructure design and carrier confinement of the nano-ridge laser diode.
Analysis of elastohydrodynamics and nutrient transport through deformable porous scaffold inside a hollow fiber membrane bioreactor
Authors: Kumar Prakash , Raja Sekhar G. P.
Published: March 2020

Hydrodynamics and nutrient transport in a hollow fiber membrane bioreactor is studied by developing a two-dimensional mathematical model in Cartesian coordinates. In a more realistic scenario, the scaffold is considered to be elastic and deformable, which undergoes deformation with the applied pore pressure. A mixture model is used to deal with the scaffold matrix, cells, and the fluid present in the scaffold region. The method of lubrication theory is incorporated when the aspect ratio of the lumen is small. The nutrient transport in the scaffold region is assumed to be governed by advection–diffusion–reaction mass balance due to the presence of cells and by advection–diffusion in the lumen and porous membrane. Analytical solution of the coupled system is presented for a short time scale where the cell growth, death, or differentiation is neglected. The results obtained focus on the effect of various parameters on the fluid flow, solid deformation, and consumption of nutrients due to different kinds of cells. It is observed that the deformation of the scaffold matrix increases monotonically with the flow rate supplied to the bioreactor. This behavior ensures that one can adjust the fluid flux to achieve optimum deformation in favor of cell growth and avoid damage of the scaffold. Moreover, a general criterion for the distribution of adequate nutrient concentration inside the bioreactor is developed to prevent the formation of the necrosis region inside the scaffold. Accordingly, the current investigation helps to arrive at suitable parameter combinations to monitor and control an ongoing experiment for optimum cell growth.
Variance of the energy of a quantum system in a time-dependent perturbation: Determination by nonadiabatic transition probabilities
Authors: Mandal Anirban , Hunt Katharine L. C.
Published: March 2020

For a quantum system in a time-dependent perturbation, we prove that the variance in the energy depends entirely on the nonadiabatic transition probability amplitudes bk(t). Landau and Lifshitz introduced the nonadiabatic coefficients for the excited states of a perturbed quantum system by integrating by parts in Dirac’s expressions for the coefficients ck(1)(t) of the excited states to first order in the perturbation. This separates ck(1)(t) for each state into an adiabatic term ak(1)(t) and a nonadiabatic term bk(1)(t). The adiabatic term follows the adiabatic theorem of Born and Fock; it reflects the adjustment of the initial state to the perturbation without transitions. If the response to a time-dependent perturbation is entirely adiabatic, the variance in the energy is zero. The nonadiabatic term bk(1)(t) represents actual excitations away from the initial state. As a key result of the current work, we derive the variance in the energy of the quantum system and all of the higher moments of the energy distribution using the values of |bk(t)|2 for each of the excited states along with the energy differences between the excited states and the ground state. We prove that the same variance (through second order) is obtained in terms of Dirac’s excited-state coefficients ck(t). We show that the results from a standard statistical analysis of the variance are consistent with the quantum results if the probability of excitation Pk is set equal to |bk(t)|2, but not if the probability of excitation is set equal to |ck(t)|2. We illustrate the differences between the variances calculated with the two different forms of Pk for vibration–rotation transitions of HCl in the gas phase.
Absolute x-ray calibration of an Amersham imaging plate scanner
Authors: Dong Yufeng , Zhang Zhe , Xu Miaohua , Du Yuhan , Zhang Chenglong , Dong Xiaomei , He Yuhang , Tan Junhao , Zhang Yihang , Zhu Changqing , Feng Jie , Cheng Lei , Li Yingjun , Li Yutong
Published: March 2020

The absolute response of the GE Amersham Typhoontm imaging plate scanner is studied in this paper. The sensitivity function of the scanner with different photomultiplier tube voltages was obtained by using a pre-calibrated Cu Kα x-ray tube. The results showed that the sensitivity function decreases exponentially with higher voltage and is also affected by the scanning pixel size. The spatial resolution and the fading effect of the imaging plate system on x rays were also investigated and compared with the previous scanner models.
Extremely solvent-enhanced absorbance and fluorescence of carbazole interpreted using a damped Franck–Condon simulation
Authors: Wang Chen-Wen , Zhu Chaoyuan , Lin Sheng Hsien
Published: March 2020

Extremely solvent-enhanced absorption and fluorescence spectra of carbazole were investigated by performing a generalized multi-set damped Franck–Condon spectral simulation. Experimental absorption and fluorescence spectra of carbazole in the gas phase were first well reproduced by performing an un-damped Franck–Condon simulation, but a one-set scaling damped Franck–Condon simulation severely underestimated the intensities of the peaks of experimental absorption and fluorescence spectra of carbazole in n-hexane. Then, a multi-set scaling damped Franck–Condon simulation was proposed and carried out for simulating the extremely solvent-enhanced absorbance and fluorescence, and here, the simulated spectra agreed well with the experimental ones. Five (four) representative solvent-enhanced normal modes corresponding to the combination of ring stretching and ring breathing vibrational motions were determined to be responsible for enhanced absorbance (fluorescence) in n-hexane solution. Furthermore, different scalings were applied to the ground and first-excited states, resulting in different enhancement of absorbance and fluorescence, and this analysis revealed atoms in the carbazole interacting with n-hexane solvent molecules and, hence, leading to different normal-mode vibrational vector patterns in the ground and first-excited states, respectively. Basically, the same conclusion was drawn from a simulation with HF-CIS and the three functionals (TD)B3LYP, (TD)B3LYP-35, and (TD)BHandHLYP. The present multi-set scaling damped Franck–Condon simulation scheme was demonstrated to successfully interpret extremely solvent-enhanced absorbance and fluorescence of carbazole in n-hexane-solvent.
Verification of an improved equation-free projective integration method for neoclassical plasma-profile evolution in tokamak geometry
Authors: Sturdevant Benjamin J. , Parker Scott E. , Chang C. S. , Hager Robert
Published: March 2020

A brute-force, long-time gyrokinetic simulation of plasma profile evolution in magnetic fusion devices is not desirable due to large computational resource requirements and a possible accumulation of numerical error. The equation-free projective integration method of Keverekidis et al. [Commun. Math. Sci. 1(4), 715–762 (2003)] is one of the outstanding candidates in projecting micro-scale simulations to a longer timescale. However, its application to tokamak plasma has not been fruitful due to the appearance of spurious transient oscillations in the lifting process, which are present when the kinetic simulations are initialized with a simplified model distribution function and which make the kinetic simulations to deviate from the desired paths. In this work, a kinetically informed lifting algorithm is added to the equation-free projective integration method, which is then verified in the electrostatic gyrokinetic particle-in-cell code XGCa [R. Hager and C. S. Chang, Phys. Plasmas 23, 042503 (2016)] for a neoclassical ion heat transport problem with adiabatic electrons. This new lifting operator is demonstrated to control spurious transients, enabling an over four-times reduction in the overall computing time in the time-evolution of the ion temperature profile in an axisymmetric toroidal plasma. Further reduction in the computing time is found to be limited due to the stability properties of the linear least squares projective integrator.
3D light-field endoscopic imaging using a GRIN lens array
Authors: Guo Changliang , Urner Tara , Jia Shu
Published: March 2020

Endoscopic observation of biological tissues with quantitative depth perception, effective volumetric recognition of anatomical features, and efficient 3D navigation is critical for optical diagnostics and minimally invasive surgery for various target diseases. Light-field techniques have recently emerged as a promising approach to 3D photography and microscopy due to their scanning-free, highly scalable, and volumetric imaging capabilities. These advantages hold great potential for application to optical endoscopy, as the existing clinical endoscopy systems rely primarily on a 2D projection or use polarized glasses to provide visual parallax of complex 3D structures. Here, we report a light-field endoscopy prototype using a GRIN lens array (GLA). The GLA-based system maintains consistent spatial measurements with clinical endoscopic systems, a compact size in comparison with compound objective lenses, as well as the ability to maximally capture the angular information necessary for 3D imaging. We also present a computational strategy combining a wave-optics model and a hybrid point-spread function for high-resolution volumetric reconstruction. The system achieves spatial resolutions of 20–60 μm and 100–200 μm in the lateral and axial dimensions, respectively, across an imaging volume of ∼5 mm × 5 mm × 10 mm. We anticipate the prototype to offer a promising paradigm for glasses-free, high-resolution 3D medical endoscopy.
Constructing auxiliary dynamics for nonequilibrium stationary states by variance minimization
Authors: Ray Ushnish , Kin-Lic Chan Garnet
Published: March 2020

We present a strategy to construct guiding distribution functions (GDFs) based on variance minimization. Auxiliary dynamics via GDFs mitigates the exponential growth of variance as a function of bias in Monte Carlo estimators of large deviation functions. The variance minimization technique exploits the exact properties of eigenstates of the tilted operator that defines the biased dynamics in the nonequilibrium system. We demonstrate our techniques in two classes of problems. In the continuum, we show that GDFs can be optimized to study the interacting driven diffusive systems where the efficiency is systematically improved by incorporating higher correlations into the GDF. On the lattice, we use a correlator product state ansatz to study the 1D weakly asymmetric simple exclusion process. We show that with modest resources, we can capture the features of the susceptibility in large systems that mark the phase transition from uniform transport to a traveling wave state. Our work extends the repertoire of tools available to study nonequilibrium properties in realistic systems.
Realization of finite-rate isothermal compression and expansion using optical feedback trap
Authors: Albay John A. C. , Lai Pik-Yin , Jun Yonggun
Published: March 2020

We experimentally realize the finite-rate isothermal process of a Brownian particle in a breathing harmonic potential. For the compression process, finite-rate equilibration can be achieved by increasing and then decreasing the stiffness of the potential to the final stiffness according to the shortcuts-to-isothermal (ScI) protocol. On the other hand, the realization of the ScI expansion is experimentally impossible with optical tweezers due to the requirement of a negative stiffness. Here, we propose a simple and elegant method to resolve this problem and demonstrate the ScI expansion by using the optical feedback trap capable of creating an arbitrary spatiotemporal potential even with a negative stiffness. In addition, we check the thermodynamic energetics such as work, heat, and internal energy, which indeed obey stochastic thermodynamics. Our method provides the possibility of a Brownian heat engine with maximum efficiency but non-vanishing power.
Preparation, thermoelectric properties, and crystal structure of boron-doped Mg2Si single crystals
Authors: Hayashi Kei , Saito Wataru , Sugimoto Kazuya , Ohoyama Kenji , Hayashi Kouichi , Happo Naohisa , Harada Masahide , Oikawa Kenichi , Inamura Yasuhiro , Miyazaki Yuzuru
Published: March 2020

Mg2Si is a potential thermoelectric (TE) material that can directly convert waste energy into electricity. In expectation of improving its TE performance by increasing electron carrier concentration, the element boron (B) is doped in Mg2Si single crystals (SCs). Their detailed crystal structures are definitely determined by using white neutron holography and single-crystal x-ray diffraction (SC-XRD) measurements. The white neutron holography measurement proves that the doped B atom successfully substitutes for the Mg site. The SC-XRD measurement confirms the B-doping site and also reveals the presence of the defect of Si vacancy (VSi) in the B-doped Mg2Si SCs. The fraction of VSi increases with increasing B-doping concentration. In the case of B-doped Mg2Si polycrystals (PCs), VSi is absent; this difference between the SCs and PCs can be attributed to different preparation temperatures. Regarding TE properties, the electrical conductivity, σ, and the Seebeck coefficient, S, decreases and increases, respectively, due to the decrease in the electron carrier concentration, contrary to the expectation. The power factor of the B-doped Mg2Si SCs evaluated from σ and S does not increase but rather decreases by the B-doping. The tendencies of these TE properties can be explained by considering that the donor effect of the B atom is canceled by the acceptor effect of VSi for the B-doped Mg2Si SCs. This study demonstrates that the preparation condition of Mg2Si should be optimized to prevent the emergence of an unexpected point defect.
Molecular structure determination: Equilibrium structure of pyrimidine (m-C4H4N2) from rotational spectroscopy (reSE) and high-levelab initiocalculation (re) agree within the uncertainty of experimental measurement
Authors: Heim Zachary N. , Amberger Brent K. , Esselman Brian J. , Stanton John F. , Woods R. Claude , McMahon Robert J.
Published: March 2020

The pure rotational spectrum of pyrimidine (m-C4H4N2), the meta-substituted dinitrogen analog of benzene, has been studied in the millimeter-wave region from 235 GHz to 360 GHz. The rotational spectrum of the ground vibrational state has been assigned and fit to yield accurate rotational and distortion constants. Over 1700 distinct transitions were identified for the normal isotopologue in its ground vibrational state and least-squares fit to a partial sextic S-reduced Hamiltonian. Transitions for all four singly substituted 13C and 15N isotopologues were observed at natural abundance and were likewise fit. Deuterium-enriched samples of pyrimidine were synthesized, giving access to all eleven possible deuterium-substituted isotopologues, ten of which were previously unreported. Experimental values of rotational constants and computed values of vibration–rotation interaction constants and electron-mass corrections were used to determine semi-experimental equilibrium structures (reSE) of pyrimidine. The reSE structure obtained using coupled-cluster with single, double, and perturbative triple excitations [CCSD(T)] corrections shows exceptional agreement with the re structure computed at the CCSD(T)/cc-pCV5Z level (≤0.0002 Å in bond distance and ≤0.03° in bond angle). Of the various computational methods examined, CCSD(T)/cc-pCV5Z is the only method for which the computed value of each geometric parameter lies within the statistical experimental uncertainty (2σ) of the corresponding semi-experimental coordinate. The exceptionally high accuracy and precision of the structure determination is a consequence of the large number of isotopologues measured, the precision and extent of the experimental frequency measurements, and the sophisticated theoretical treatment of the effects of vibration–rotation coupling and electron mass. Taken together, these demanding experimental and computational studies establish the capabilities of modern structural analysis for a prototypical monocyclic aromatic compound.
Interchange of humpback whales (Megaptera novaeangliae) between northern Philippines and Ogasawara, Japan, has implications for conservation
Authors: Nakagun Shotaro , Smoll Laetitia I. , Sato Takayuki , Layusa Cynthia A. A. , Acebes Jo Marie V.
Published: March 2020

Humpback whales (Megaptera novaeangliae) in the western North Pacific breed in the Philippines and Japan, where there is relatively little scientific data available, leading to uncertainty about their population status and structure. This study investigates links between humpback whale populations in northern Philippines and Ogasawara, Japan, through a comparison of the most recent fluke identification catalogues. The Philippines catalogue (1999–2016) included 234 individuals, and the Ogasawara catalogue (1987–2014), 1389 individuals. The number of matched individuals was 86 (including 14 known females and 40 known males), corresponding to 36.8% of the Philippines and 6.2% of the Ogasawara catalogues. The findings included four within-season matches, with travel times as short as 25 days. The results suggest that a considerable portion of whales utilising Philippine waters pass through and also utilise the Ogasawara region, but the majority of whales found off Ogasawara either stay in that location, move to different breeding grounds, or remain out of the sampling area. Nevertheless, in light of the high site fidelity of individuals in the Philippines and Ogasawara area, as well as constant evidence of breeding activities, these regions are of importance to the lesser known western North Pacific subpopulation. Humpback whales migrating to this part of the world are estimated to be in relatively low abundance, therefore continued conservation attention is needed.
Novel electronic nematicity in heavily hole-doped iron pnictide superconductors
Authors: Ishida Kousuke , Tsujii Masaya , Hosoi Suguru , Mizukami Yuta , Ishida Shigeyuki , Iyo Akira , Eisaki Hiroshi , Wolf Thomas , Grube Kai , v. Löhneysen Hilbert , Fernandes Rafael M. , Shibauchi Takasada
Published: March 2020

Significance

Strongly correlated electron systems often exhibit exotic states of matter, and perhaps the most surprising is the electronic nematicity with broken rotational symmetry. In such nematic states, the nematic director usually points to certain directions of the underlying crystal, and, thus, these states have been classified as Ising-type. Here, we find in a heavily hole-doped iron-pnictide system that the director is rotated by 45° from the Fe–Fe direction. Moreover, there is a doping range that shows a signature of a class of electronic quantum liquid-crystalline state of XY type, where the nematic director can point anywhere in the Fe planes. These findings reveal another type of quantum liquid crystals, which are expected to host several unique quantum many-body phenomena.
Emergence of chromatin hierarchical loops from protein disorder and nucleosome asymmetry
Authors: Sridhar Akshay , Farr Stephen E. , Portella Guillem , Schlick Tamar , Orozco Modesto , Collepardo-Guevara Rosana
Published: March 2020

Protein flexibility and disorder is emerging as a crucial modulator of chromatin structure. Histone tail disorder enables transient binding of different molecules to the nucleosomes, thereby promoting heterogeneous and dynamic internucleosome interactions and making possible recruitment of a wide-range of regulatory and remodeling proteins. On the basis of extensive multiscale modeling we reveal the importance of linker histone H1 protein disorder for chromatin hierarchical looping. Our multiscale approach bridges microsecond-long bias-exchange metadynamics molecular dynamics simulations of atomistic 211-bp nucleosomes with coarse-grained Monte Carlo simulations of 100-nucleosome systems. We show that the long C-terminal domain (CTD) of H1—a ubiquitous nucleosome-binding protein—remains disordered when bound to the nucleosome. Notably, such CTD disorder leads to an asymmetric and dynamical nucleosome conformation that promotes chromatin structural flexibility and establishes long-range hierarchical loops. Furthermore, the degree of condensation and flexibility of H1 can be fine-tuned, explaining chromosomal differences of interphase versus metaphase states that correspond to partial and hyperphosphorylated H1, respectively. This important role of H1 protein disorder in large-scale chromatin organization has a wide range of biological implications.
Spatially separating redox centers on 2D carbon nitride with cobalt single atom for photocatalytic H
2
O
2
production
Authors: Chu Chiheng , Zhu Qianhong , Pan Zhenhua , Gupta Srishti , Huang Dahong , Du Yonghua , Weon Seunghyun , Wu Yueshen , Muhich Christopher , Stavitski Eli , Domen Kazunari , Kim Jae-Hong
Published: March 2020

Significance

Photocatalysts frequently require simultaneous loading of oxidative and reductive cocatalysts to achieve both efficient half-reactions within a single material. Nevertheless, unregulated loading and distribution of two cocatalysts will result in direct contact between oxidation and reduction centers, leading to detrimental charge recombination. This research presents a center/edge approach to load two redox cocatalysts with controlled physical separation in atomistic scale using single-atom architecture. This spatial separation is critical for enhancing surface charge separation and achieving efficient H
2
O
2
production. We report that redox cocatalysts are spatially separated on a two-dimensional (2D) photocatalyst, which opens an approach for achieving both efficient oxidation and reduction reactions on 2D photocatalysts.
Mechanism and site of action of big dynorphin on ASIC1a
Authors: Borg Christian B. , Braun Nina , Heusser Stephanie A. , Bay Yasmin , Weis Daniel , Galleano Iacopo , Lund Camilla , Tian Weihua , Haugaard-Kedström Linda M. , Bennett Eric P. , Lynagh Timothy , Strømgaard Kristian , Andersen Jacob , Pless Stephan A.
Published: March 2020

Acid-sensing ion channels (ASICs) are proton-gated cation channels that contribute to neurotransmission, as well as initiation of pain and neuronal death following ischemic stroke. As such, there is a great interest in understanding the in vivo regulation of ASICs, especially by endogenous neuropeptides that potently modulate ASICs. The most potent endogenous ASIC modulator known to date is the opioid neuropeptide big dynorphin (BigDyn). BigDyn is up-regulated in chronic pain and increases ASIC-mediated neuronal death during acidosis. Understanding the mechanism and site of action of BigDyn on ASICs could thus enable the rational design of compounds potentially useful in the treatment of pain and ischemic stroke. To this end, we employ a combination of electrophysiology, voltage-clamp fluorometry, synthetic BigDyn analogs, and noncanonical amino acid-mediated photocrosslinking. We demonstrate that BigDyn binding results in an ASIC1a closed resting conformation that is distinct from open and desensitized states induced by protons. Using alanine-substituted BigDyn analogs, we find that the BigDyn modulation of ASIC1a is primarily mediated through electrostatic interactions of basic amino acids in the BigDyn N terminus. Furthermore, neutralizing acidic amino acids in the ASIC1a extracellular domain reduces BigDyn effects, suggesting a binding site at the acidic pocket. This is confirmed by photocrosslinking using the noncanonical amino acid azidophenylalanine. Overall, our data define the mechanism of how BigDyn modulates ASIC1a, identify the acidic pocket as the binding site for BigDyn, and thus highlight this cavity as an important site for the development of ASIC-targeting therapeutics.
DNA origami protection and molecular interfacing through engineered sequence-defined peptoids
Authors: Wang Shih-Ting , Gray Melissa A. , Xuan Sunting , Lin Yiyang , Byrnes James , Nguyen Andy I. , Todorova Nevena , Stevens Molly M. , Bertozzi Carolyn R. , Zuckermann Ronald N. , Gang Oleg
Published: March 2020

Significance

DNA nanotechnology provides a structural toolkit for the fabrication of programmable DNA nano-constructs; however, their use in biomedical applications is challenging due the limited structural integrity in complex biological fluids. Here, we report a class of tailorable molecular coatings, peptoids, which can efficiently stabilize three-dimensional wireframed DNA constructs under a variety of biomedically relevant conditions, including magnesium-ion depletion and presence of degrading nuclease. Furthermore, we show that peptoid-coated DNA constructs offer a controllable anticancer drug release and an ability to display functional biomolecules on the DNA surfaces. Our study demonstrates an approach for building multifunctional and environmentally robust DNA-based molecular structures for nanomedicine and biosensing.
Molecular mechanisms of Evening Complex activity in
Arabidopsis
Authors: Silva Catarina S. , Nayak Aditya , Lai Xuelei , Hutin Stephanie , Hugouvieux Véronique , Jung Jae-Hoon , López-Vidriero Irene , Franco-Zorrilla Jose M. , Panigrahi Kishore C. S. , Nanao Max H. , Wigge Philip A. , Zubieta Chloe
Published: March 2020

The Evening Complex (EC), composed of the DNA binding protein LUX ARRHYTHMO (LUX) and two additional proteins EARLY FLOWERING 3 (ELF3) and ELF4, is a transcriptional repressor complex and a core component of the plant circadian clock. In addition to maintaining oscillations in clock gene expression, the EC also participates in temperature and light entrainment, acting as an important environmental sensor and conveying this information to growth and developmental pathways. However, the molecular basis for EC DNA binding specificity and temperature-dependent activity were not known. Here, we solved the structure of the DNA binding domain of LUX in complex with DNA. Residues critical for high-affinity binding and direct base readout were determined and tested via site-directed mutagenesis in vitro and in vivo. Using extensive in vitro DNA binding assays of LUX alone and in complex with ELF3 and ELF4, we demonstrate that, while LUX alone binds DNA with high affinity, the LUX–ELF3 complex is a relatively poor binder of DNA. ELF4 restores binding to the complex. In vitro, the full EC is able to act as a direct thermosensor, with stronger DNA binding at 4 °C and weaker binding at 27 °C. In addition, an excess of ELF4 is able to restore EC binding even at 27 °C. Taken together, these data suggest that ELF4 is a key modulator of thermosensitive EC activity.
Tumor cell-intrinsic PD-1 receptor is a tumor suppressor and mediates resistance to PD-1 blockade therapy
Authors: Wang Xiaodong , Yang Xiaohui , Zhang Chang , Wang Yang , Cheng Tianyou , Duan Liqiang , Tong Zhou , Tan Shuguang , Zhang Hangjie , Saw Phei Er , Gu Yinmin , Wang Jinhua , Zhang Yibi , Shang Lina , Liu Yajuan , Jiang Siyuan , Yan Bingxue , Li Rong , Yang Yue , Yu Jie , Chen Yunzhao , Gao George Fu , Ye Qinong , Gao Shan
Published: March 2020

Significance

This study indicates that a subpopulation of tumor cells expresses both PD-1 and PD-L1, which decreases the tumor growth by suppressing the canonical signaling pathways, i.e. the AKT and ERK1/2 pathways. In the absence of adaptive immune system, tumor cell-intrinsic PD-1/PD-L1 mediates the resistance to the treatment with FDA-approved anti-PD-1/PD-L1 antibodies by activating AKT and ERK1/2. These findings provide an additional explanation for resistance to cancer immunotherapy.