bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metal- and Additive-Free Synthesis of α-Hydroxyamino Ketones Enabled by Organophotocatalyst
Authors: Akiyama Takahiko , Yamanomoto Ken , Matsudaira Tadachika 
Published: March 2023

AbstractWe report herein a straightforward method for the synthesis of α-hydroxyamino ketones, which involves the benzoylation reaction of nitrones with 2-benzoyl-2-phenylbenzothiazoline under organophotocatalysis. This method offers access to a variety α-hydroxyamino ketones without the use of any transition-metal catalyst or base. Control experiments suggested that the reaction proceeded through a benzoyl radical addition to nitrone. Benzothiazoline was found to be a more suitable radical precursor than Hantzsch ester.
Additive Manufacturing of Titanium Implants for Skull Reconstruction in 2 Dogs after Bone Tumour Excision
Authors: van den Brink Eline J.C. , Grinwis Guy C.M. , Willemsen Koen , Driessen Floor , Boroffka Susanne A.E.B. , Meij Björn P. 
Published: March 2023

AbstractIn two dogs, skull defects were closed with a patient-specific implant created by additive manufacturing after excision of tumours of the skull. Both dogs presented with a space-occupying mass in which excisional surgery without the use of implants would have resulted in incomplete closure due to extensive bone defects of the skull. The aim of the present case report is to describe the use of individualized three-dimensional-printed titanium implants for skull reconstruction following oncological surgery. The reconstructive implant-based surgeries performed in these patients were feasible without complications.
All-fiber-device-coupled compact, transportable ultra-stable laser
Authors: Zhao W. , Yang H. , Wu H. , Fu Y. , Ge J. , Zhang S. 
Published: March 2023

In response to the demand for operation in non-laboratory environments, there has been a trend toward the development of compact, transportable ultra-stable lasers. This paper reports on this sort of laser system assembled in a cabinet. The whole optical part utilizes fiber-coupled devices to simplify the integration. In addition, spatial beam collimation and alignment into the high-finesse cavity are realized by a five-axis positioner and a focus-adjustable fiber collimator, which significantly relax the alignment and adjustment. A theoretical analysis is performed on how the collimator adjusts the beam profile and coupling efficiency. The support structure of the system is specially designed as well so that it features robustness and transportation without performance degradation. The observed linewidth is 1.4 Hz within a duration of 1 s. After subtracting the linear drift of 70 mHz/s, the fractional frequency instability is better than 4 × 10−15, for the averaging time ranging from 1 to 100 s, which is close to the thermal noise limit of the high-finesse cavity.
Dynamic measurement of gas flow using acoustic resonance tracking
Authors: Pope Jodie G. , Schmidt James W. , Gillis Keith A. 
Published: March 2023

The National Institute of Standards and Technology measured gas flows exiting large, unthermostated, gas-filled, pressure vessels by tracking the time-dependent pressure P(t) and resonance frequency fN(t) of an acoustic mode N of the gas remaining in each vessel. This is a proof-of-principle demonstration of a gas flow standard that uses P(t), fN(t), and known values of the gas's speed of sound w(p,T) to determine a mode-weighted average temperature ⟨T⟩φ of the gas remaining in a pressure vessel while the vessel acts as a calibrated source of gas flow. To track fN(t) while flow work rapidly changed the gas’s temperature, we sustained the gas's oscillations using positive feedback. Feedback oscillations tracked ⟨T⟩φ with a response time of order 1/fN. In contrast, driving the gas’s oscillations with an external frequency generator yielded much slower response times of order Q/fN. (For our pressure vessels, Q ∼ 103–104, where Q is the ratio of the energy stored to the energy lost in one cycle of oscillation.) We tracked fN(t) of radial modes in a spherical vessel (1.85 m3) and of longitudinal modes of a cylindrical vessel (0.3 m3) during gas flows ranging from 0.24 to 12.4 g/s to determine the mass flows with an uncertainty of 0.51 % (95 % confidence level). We discuss the challenges in tracking fN(t) and ways to reduce the uncertainties.
O
-GlcNAcylation promotes tumor immune evasion by inhibiting PD-L1 lysosomal degradation
Authors: Zhu Qiang , Wang Hongxing , Chai Siyuan , Xu Liang , Lin Bingyi , Yi Wen , Wu Liming 
Published: March 2023

Programmed-death ligand 1 (PD-L1) and its receptor programmed cell death 1 (PD-1) mediate T cell–dependent immunity against tumors. The abundance of cell surface PD-L1 is a key determinant of the efficacy of immune checkpoint blockade therapy targeting PD-L1. However, the regulation of cell surface PD-L1 is still poorly understood. Here, we show that lysosomal degradation of PD-L1 is regulated by
O
-linked
N
-acetylglucosamine (
O
-GlcNAc) during the intracellular trafficking pathway.
O
-GlcNAc modifies the hepatocyte growth factor-regulated tyrosine kinase substrate (HGS), a key component of the endosomal sorting machinery, and subsequently inhibits its interaction with intracellular PD-L1, leading to impaired lysosomal degradation of PD-L1.
O
-GlcNAc inhibition activates T cell–mediated antitumor immunity in vitro and in immune-competent mice in a manner dependent on HGS glycosylation. Combination of
O
-GlcNAc inhibition with PD-L1 antibody synergistically promotes antitumor immune response. We also designed a competitive peptide inhibitor of HGS glycosylation that decreases PD-L1 expression and enhances T cell–mediated immunity against tumor cells. Collectively, our study reveals a link between
O
-GlcNAc and tumor immune evasion, and suggests strategies for improving PD-L1-mediated immune checkpoint blockade therapy.
A new superhard material C5N2 assembled from diamane: a first-principles study
Authors: Shao Jinfan , Qian Yan , Kan Erjun , Wu Haiping 
Published: March 2023

Abstract
Due to the shortage of diamond and cubic boron nitride (BN) and the lack of other potential rivals, searching for suitable superhard materials is still attracting tremendous research interests, especially those with special properties except for semiconducting and insulating characteristics. Beyond previous synthetic methods, here we give a new approach of designing superhard materials (i.e. stacking diamane layers through chemical adsorption of molecules at the interface) via first-principles calculations. As a result, a superhard carbon-rich C5N2 compound with monoclinic C
2 symmetry is designed by inserting CN4 molecule between diamane layers, and it exhibits dynamical and mechanical stability at ambient environment. The hardness is estimated as 74.9 GPa, showing superhard nature. Different from indirect band gap insulators of diamond and cubic BN, C5N2 behaves as a direct band gap semiconductor with an energy gap of ∼2.10 eV. Besides, the properties of C5N2 can be effectively regulated by controlling the adsorbed molecules, for instance, it would turn into ferromagnetic phase with introduction of sp
3 hybridized three-folded C atoms and sp
2 hybridized two-fold coordinated N atoms. The estimated Curie temperatures of some ferromagnetic superhard phases are preferably above room temperature. Additionally, these ferromagnetic phases show diverse electronic properties, such as spin gapless semiconductor, bipolar magnetic semiconductor, metal, etc. This work opens a potential way to design superhard materials and tailor their physical properties, and can arouse their applications in spintronic field.
Plutonium-241 as a possible isotope for neutrino mass measurement and capture
Authors: de Groot Nicolo 
Published: March 2023

Abstract
Tritium has been the isotope of choice for measurements of the absolute neutrino mass and planned detection of the relic neutrino background. The low mass of 3H leads to large recoil energy of the nucleus. This has emerged as a limiting factor in both measurements. We investigate 241Pu as an alternative. The recoil is 80 times smaller and it has similar decay energy and a lifetime to 3H. We evaluate for the first time its soft-neutrino capture cross-section and find (σ
v)
ν
= 1.52 × 10−45 cm2. This is 40% of the capture cross-section for tritium, making 241Pu an interesting alternative for 3H.
Research on wingtip distance measurement of high-speed coaxial helicopter based on 77 GHz FMCW millimeter-wave radar
Authors: Zhang Zhiyuan , Qiu Zurong , Hu Wenchuan , Lu Yaohuan , Zheng Wenjie 
Published: March 2023

Abstract
Aiming at the requirements of short-range, high-precision, and high-speed measurement of coaxial helicopter wingtip distance measurement, a millimeter-wave radar wingtip distance measurement scheme is proposed, and the ranging accuracy of frequency-modulated continuous wave millimeter-wave radar is improved by optimizing the frequency estimation method and the beat-frequency signal processing process. The multi-antenna data coherent superposition method and the correlation search for the estimated frequency are used to shorten the measurement period, and at the same time, the ranging accuracy of the millimeter-wave radar can be improved, and the single measurement time can be guaranteed. Based on frequency refinement, frequency offset method, phase method, amplitude method and fitted approximation method, the frequency estimation of millimeter wave radar differential frequency signal is combined with the influence of bandwidth, measured target shape and material on ranging to improve millimeter wave radar ranging performance comprehensively. Through simulations and experiments, the accuracy, stability, time consuming and application conditions of the optimized algorithm are comprehensively evaluated, and the feasibility of millimeter wave radar wingtip ranging is verified.
Improved and accurate fault diagnostic model for gas turbine based on 2D-wavelet transform and generative adversarial network
Authors: Yao Kun , Wang Ying , Fan Shuangshuang , Fu Junfeng , Wan Jie , Cao Yong 
Published: March 2023

Abstract
Severe working environments cause gas turbines to break down, which can directly affect their performance. Research on the diagnostic methods for gas turbine faults, such as, gas path faults and sensor failures, has always raised concerns. However, traditional fault diagnosis algorithms mostly use instantaneous data rather than time-series data, because they cannot efficiently use time-series analysis to extract fault features and improve algorithm accuracy. Problems with sparse fault samples and categories are also encountered with these algorithms. In this study, a gas turbine fault diagnostic method based on a 2D-wavelet transform and generative adversarial network (GAN) was proposed. The data preprocessing method, 2D-wavelet transform, of multiple time series images was used to obtain fault features. Based on the Fréchet inception distance, a performance evaluation index, an optimal generator built from a deep convolutional GAN model was selected to solve sparse or imbalanced datasets. The classification accuracy of the four algorithms, namely, random forest, support vector machine, convolutional neural network, and deep neural network, verified the performance of the data preprocessing and dataset building methods mentioned earlier. Compared with the original data, the 2D wavelet transform effectively improved the model accuracy. The generated samples also improved the misclassification issue caused by the imbalanced dataset; however, the ratio of real and generated samples in datasets still requires more attention.
An adaptive threshold method with error correction for pedestrian inertial navigation system
Authors: Yang Bo , Ma Yongtao , Liang Xiuyan , Tian Chenglong , Su Dianfei 
Published: March 2023

Abstract
As an effective method for reducing accumulated errors in pedestrian navigation systems based on foot-mounted inertial measurement unit, the zero velocity update is widely used in global navigation satellite system signal rejection environments that require accurate zero velocity detection. However, the detection accuracy of the classical fixed threshold method is not satisfactory under complex gaits. In this paper, an adaptive threshold method with error correction is proposed to increase the detection accuracy without adding sensors. In this method, an adaptive threshold model based on gait intensity, which can dynamically adjust the zero velocity detection threshold under complex gaits, is established. Afterward, error correction is suggested to identify and correct misjudgments in zero velocity detection by analyzing the zero velocity interval in one gait cycle. We build an actual pedestrian inertial navigation system to evaluate the proposed method. The experimental results demonstrate that the average zero velocity detection accuracy of the proposed method under complex gaits of different people is 98.67%, and the end-to-end positioning error is about 0.53% of the total distance during long-distance movement.
6D pose estimation of object based on fused region-level feature in cluttered scenes
Authors: Liu Xiangpeng , Duanmu Huiping , An Kang , Wang Wancheng , Song Yaqing , Gu Qingying , Yuan Bo , Wang Danning 
Published: March 2023

Abstract
RGB-based methods have certain disadvantages because they lack 3D information and cannot cope with the pose estimation problem in cluttered scenes. Therefore, we propose a region-level pose estimation network that uses RGB-D images. We first extracted the objects’ color features and geometric features by convolutional neural networks (CNN) and PointNet, respectively, and then performed feature fusion. The fused features were fed into a region-level feature extraction network to obtain the region-level features, which extracted the local geometry features from the point cloud and learned the point set’s semantic information. We used the output of the region-level feature extraction network to perform region-level pose estimation, then selected the pose with the highest confidence level as the output and iteratively optimized the pose to obtain the final results. The experimental results showed that the proposed solution performed well on the LINEMOD data set, which verified the effectiveness of the proposed method in the pose estimation problem and the algorithm’s robustness in severely cluttered scenes.
Global well-posedness of slightly supercritical SQG equations and gradient estimate
Authors: Choi Hyungjun 
Published: March 2023

Abstract
We prove the global regularity of smooth solutions for a dissipative surface quasi-geostrophic (SQG) equation with both velocity and dissipation logarithmically supercritical compared to the critical equation. By this, we mean that a symbol defined as a power of logarithm is added to both velocity and dissipation terms to penalize the equation’s criticality. Our primary tool is the nonlinear maximum principle which provides transparent proofs of global regularity for nonlinear dissipative equations. Combining the nonlinear maximum principle with a modulus of continuity, we prove an uniform-in-time gradient estimate for the critical and slightly supercritical SQG equation. It improves the previous double exponential bound by Kiselev–Nazarov–Volberg to the single exponential. In addition, we prove the eventual exponential decay of the solutions.
Impact of respiratory motion on proton pencil beam scanning FLASH radiotherapy: an in silico and phantom measurement study
Authors: Yang Yunjie , Kang Minglei , Huang Sheng , Chen Chin-Cheng , Tsai Pingfang , Hu Lei , Yu Francis , Hajj Carla , Choi J Isabelle , Tome Wolfgang A , Simone Charles B , Lin Haibo 
Published: March 2023

AbstractObjective. To investigate the effects of respiratory motion on the delivered dose in the context of proton pencil beam scanning (PBS) transmission FLASH radiotherapy (FLASH-RT) by simulation and phantom measurements.Approach. An in-house simulation code was employed to performin silicosimulation of 2D dose distributions for clinically relevant proton PBS transmission FLASH-RT treatments. A moving simulation grid was introduced to investigate the impacts of various respiratory motion and treatment delivery parameters on the dynamic PBS dose delivery. A strip-ionization chamber array detector and an IROC motion platform were employed to perform phantom measurements of the 2D dose distribution for treatment fields similar to those used for simulation.Main results. Clinically relevant respiratory motion and treatment delivery parameters resulted in degradation of the delivered dose compared to the static delivery as translation and distortion. Simulation showed that the gamma passing rates (2 mm/2% criterion) and target coverage could drop below 50% and 80%, respectively, for certain scenarios if no mitigation strategy was used. The gamma passing rates and target coverage could be restored to more than 95% and 98%, respectively, for short beams delivered at the maximal inhalation or exhalation phase. The simulation results were qualitatively confirmed in phantom measurements with the motion platform.Significance. Respiratory motion could cause dose quality degradation in a clinically relevant proton PBS transmission FLASH-RT treatment if no mitigation strategy is employed, or if an adequate margin is not given to the target. Besides breath-hold, gated delivery can be an alternative motion management strategy to ensure high consistency of the delivered dose while maintaining minimal dose to the surrounding normal tissues. To the best of our knowledge, this is the first study on motion impacts in the context of proton transmission FLASH radiotherapy.
Validation of Monte Carlo simulated absorbed-dose-to-water inside a custom SPECT/CT phantom using active and passive dosimeters: a feasibility study using 99mTc
Authors: Bertinetti Andrew , Rodrigues Miesher , Palmer Benjamin , Garcia Timothy R , Vija A Hans , Culberson Wesley 
Published: March 2023

Abstract

Objective.This project aims to provide a novel method for performing dosimetry measurements on TRT radionuclides using a custom-made SPECT/CT compatible phantom, common active and passive detectors, and Monte Carlo simulations. In this work we present a feasibility study using 99mTc for a novel approach to obtaining reproducible measurements of absorbed-dose-to-water from radionuclide solutions using active and passive detectors in a custom phantom for the purpose of benchmarking Monte Carlo-based absorbed-dose-to-water estimates. Approach. A cylindrical, acrylic SPECT/CT compatible phantom capable of housing an IBA EFD diode, SNC600c Farmer type ion chamber, and TLD-100 microcubes was designed and built for the purpose of assessing internal absorbed-dose-to-water at various points within a solution of 99mTc. The phantom is equipped with removable inserts that allow for numerous detector configurations and is designed to be used for verification of SPECT/CT-based absorbed-dose estimates with traceable detector measurements at multiple locations. Three experiments were conducted with exposure times ranging from 11 to 21 h with starting activities of approximately 10–16 GBq. Measurement data was compared to Monte Carlo simulations using the egs_chamber user code in EGSnrc 2019. Main results. In general, the ionization chamber measurements agreed with the Monte Carlo simulations within k = 1 uncertainty values (±4% and ±7%, respectively). Measurements from the TLDs yielded results within k = 1 agreement of the MC prediction (±6% and ±5%, respectively). Agreement within k = 1 uncertainty (±6% and ±7%, respectively) was obtained for the diode for one of three conducted experiments. Significance. While relatively large uncertainties remain, the agreement between measured and simulated absorbed-doses provides proof of principal that dosimetry of radionuclide solutions with active detectors may be performed using this type of phantom with potential modifications for beta-emitting radionuclides to be introduced in future work.
Numerical experiments on the total D–D fusion neutron yield versus deuterium pressure for different energy plasma focus devices using the Lee model code
Authors: Wahbe S , Abou-Ali Y , Akel M , Lee S , Marciniak L 
Published: March 2023

Abstract
Numerical experiments using the Lee model code were carried out to compute the total D–D fusion neutron yield versus initial deuterium pressure for nine different plasma focus devices [PF50, AACS, PF400J, PF2.2, UNU-ICTP, PFZ200, PF24, PF78, Poseidon]. The computed data were compared with the published experimental results. In addition, the maximum discharge current, the pinch current and the pinch ion number density, as a function of initial deuterium pressure, were discussed, as well as their effect on the neutron yield. The optimum pressures that correspond to the maximum neutron yield Y
n were obtained for all considered devices, with reference to the specific plasma focus properties. The scaling laws for the D–D fusion neutron production, in terms of storage energies E
0 and pinch current I
pinch, were derived. The scaling of Y
n with I
pinch and E
0 over the whole range of investigated energies up to 300 kJ has been obtained as follows:

Y

n

∼

I

pinch

5

,

Y

n

∼

E
0

1.95

. These laws are important in the planning and design of a plasma focus as a potentially powerful pulse neutron source.
Demonstration of p-GaN/AlGaN/GaN-based ultraviolet phototransistors with sub-saturated transfer characteristics
Authors: Chen Dingbo , Zhang Penghao , Wang Luyu , Huang Wei 
Published: March 2023

Abstract
We report ultraviolet phototransistors (UVPTs) based on p-GaN/AlGaN/GaN high-electron-mobility transistors (HEMTs). Thanks to the effective depletion of the two-dimensional electron gas by the p-GaN layer, a dark current as low as 5.2 × 10−10A mm−1 was achieved. Moreover, a unique sub-saturated region can be formed in the transfer curve of the UVPTs due to the special photogenerated electric field in the heterostructure, which endows the device with a large photo-to-dark current ratio over 105. In particular, responsivity up to 1.3 × 108 and 6.1 × 103 A W−1 was demonstrated at gate voltage of 5 and 0.68 V, respectively. The minimum rise time and fall time of the device transient response were measured to be around 1.8 ms and 8.8 ms, respectively. This work shows great UV detection potential of the p-GaN/AlGaN/GaN HEMTs, which opens up possibilities of realizing multifunctional enhancement HEMTs for future III–V photonic integrated devices and systems.