bluuebunny/crossref_metadata_2025 huggingface dataset:
Modified Ultrafiltration PostExtracorporeal Membrane Oxygenation
Authors: Deptula Joseph , Karl Thomas R. , Griffin Dee Ann , Fogg Sherrie
Published: December 2023

Modified ultrafiltration (MUF) has been widely used for the removal of extracellular water in the immediate postcardiopulmonary bypass (CPB) period. The reported benefits of this technique are improved hematological status and hemodynamic stability post-CPB, as well as a decrease in blood utilization during the operation. MUF has also been associated with improved pulmonary status along with enhanced myocardial performance. With these benefits in mind, we have explored the possible advantages of using MUF following extracorporeal membrane oxygenation (ECMO). The theoretical advantages of using MUF post-ECMO are the reduction of blood use prior to removal from ECMO for optimization of hemoglobin levels, improved pulmonary compliance decreasing the duration of ventilatory support, improved myocardial function, as well as the other reported benefits described with MUF post-CPB. This report communicates the technique used to perform MUF post- ECMO, as well as a simple MUF circuit design for use in the intensive care unit setting.
Limitations Using the Vacuum-Assist Venous Drainage Technique During Cardiopulmonary Bypass Procedures
Authors: Jegger David , Tevaearai Hendrik T. , Mueller Xavier M. , Horisberger Judith , von Segesser Ludwig K.
Published: December 2023

Vacuum-assist venous drainage (VAVD) can increase venous blood return during cardiopulmonary bypass (CPB) procedures. However, the negative pressure created in the closed cardiotomy reservoir can be transmitted to the oxygenator if a nonocclusive or centrifugal arterial pump is used, resulting in bubble transgression (BT) from the gas to blood compartment of the oxygenator. We analyzed the vacuum pressure required to produce BT using an in vitro circuit including successively a closed reservoir, a pump (centrifugal or roller), and an oxygenator. A constant hydrostatic pressure was maintained onto the oxygenator. Vacuum was applied on the cardiotomy reservoir, progressively increasing negative pressure from 0 to −80 mmHg and monitoring BT with a bubble detector. Six different oxygenators were compared. A partially occlusive roller pump and a centrifugal pump were compared to a control, which was without any pump. A mean negative pressure of −53 ± 7 mmHg was necessary to produce BT in all the oxygenators in the absence of a pump. The presence of a centrifugal pump between the reservoir and the oxygenator significantly increased the negative pressure required to produce BT compared to the control (−67 ± 7 mmHg, p < .05). No bubbles were detected using the roller pump (>−80 mmHg needed for BT), thus statistically significant when compared to the centrifugal pump (p < .05). The centrifugal pump offers significant resistance to BT but not as much compared to the roller pump, though BT cannot be prevented if the pump is turned off while the vacuum remains on the reservoir. Therefore, VAVD is a safe technique as long as the perfusionist stops the vacuum when the arterial pump is no longer in use.
Nonparametric three-vector model predictive current control for permanent magnet synchronous motor
Authors: ZHANG Yufeng , WU Zihui , YAN Qi , HUANG Nan , DU Guanghui , HE Hucheng , ZHOU Yong
Published: December 2023

Multi-vector model predictive control of permanent magnet synchronous motor can effectively overcome the shortcomings of conventional single-vector model predictive control such as large motor current ripples and limited control accuracy, but its control performance is more susceptible to the influence of motor parameter perturbation. To improve the robustness of the multi-vector predictive control algorithm under the motor parameter perturbation, a novel nonparametric three-vector model predictive current control method for permanent magnet synchronous motors is proposed in this paper. Through constructing an ultra-local predictive current model based on the input and output signals of the permanent magnet synchronous motor, the influence of motor parameter perturbation on current prediction is avoided, and a disturbance observer is designed to estimate the non-modeled and perturbed parts of the ultra-local model. In addition, the direct calculation method of vector duty cycles based on current error is introduced to suppress the influence of motor parameter uncertainty on the duty cycle calculation link, which further improves the system robustness. Finally, simulations and experiments of the proposed method are demonstrated to compare with the conventional parametric three-vector model predictive current control, and the results show that the proposed control strategy can effectively suppress the disturbances caused by the motor parameters and ensure the steady-state performance during motor operation.
Research on billet optimization and forming influence rule of shaft forging
Authors: YIN Ranhao , LIU Dong , CHEN Jingqing , HAN Shun , WANG Chunxu , LI Yong , WANG Jianguo
Published: December 2023

In this paper, DEFORM-2D numerical simulation software is used to simulate the forming process parameters of C250 steel. Through the optimization of the metal flow law of the billet in the extrusion forming process and the strain evolution law of the strain zone of the big end, small end and rod in the extrusion process, studied on shape and extrusion ratio (lambda), lower die cone Angle (α4) initial temperature, extrusion speed (v), block (T0) and the sizing zone length (H2) for the peak load, forgings at the top of the building size Z strain zone width X, small head, big head end diameter end strain zone length, stem region Y strain uniformity, outlet temperature uniformity and forging parts where the head end set the influence law of temperature uniformity. Finally, the experiment is verified.
Urinscreenings auf Betäubungsmittel unter gerichtlichen
Abstinenzauflagen – Vergleichsvalidität von forensischtoxikologischen
Analysen unter Mitwirkung des Öffentlichen
Gesundheitsdienstes
Authors: Kappl Ursula , Huppertz Bernd , Stöver Heino , Stich Heribert
Published: December 2023

Ziel der Studie Erfassung der Vergleichsvalidität zwischen
qualitativen und quantitativen Analysen bei Urinscreenings auf definierte
Betäubungsmittelrückstände unter gerichtlichen
Abstinenzauflagen.

Methodik Nach Einführung eines validen Marker-Systems auf der
Basis der Einnahme einer definierten Zuckersubstanz und deren Nachweis im Urin
von Betroffenen wurden ab dem Jahre 2006 in Amtshilfe für Einrichtungen
der Bewährungshilfe Urinproben auf Nachweise von
Betäubungsmitteln (BTM) an einem bayerischen Gesundheitsamt asserviert
und an ein externes Labor übersandt, um forensisch-toxikologische
Analysen auf definierte BTMs durchzuführen. Die qualitativen und
quantitativen Laborergebnisse wurden dem Gesundheitsamt rückgemeldet,
sodass in der Folgezeit ein digitalbasierter Datensatz von insgesamt 380
Personen mit mehr als 27.000 Einzelanalysen aus insgesamt 14 konsekutiven
Kalenderjahren etabliert und retrospektiv in anonymisierter Form ausgewertet
werden konnte.

Ergebnisse Die Gesamtprävalenzen von BTM-positiven Befunden waren
für die qualitativen mit 2,7% (n=366 von 13.531) und
für die nachfolgenden quantitativen Ergebniskategorisierungen mit
2,6% (n=348 von 13.525) anzugeben, wobei in beiden Testmethoden
am häufigsten Cannabis und Opiate nachgewiesen werden konnten. Unter
Verwendung des Kappa-Koeffizienten als quantitatives Maß für die
Übereinstimmung beider Testverfahren zeigten sich mitunter bei den
Testergebnissen für Buprenorphin mit 1,000 die höchsten und
für PCP mit 0,880 die geringsten Übereinstimmungen. Für
alle zehn unterschiedlichen BTMs waren bei unterschiedlichen
substanzspezifischen Fallzahlen der Analysen keine alters- und
geschlechtsspezifischen Schichtungen festzustellen.

Schlussfolgerung Basierend auf die starken bis sehr starken
Übereinstimmungen zwischen qualitativen und quantitativen
BTM-Analyseergebnissen konnte angenommen werden, dass beide Analyseverfahren
Verstöße gegen Abstinenzauflagen präzise erfassten und
als hinreichend begründend für gerichtliche Entscheidungen
gemäß dem Betäubungsmittelgesetz (BtMG) einzustufen
waren. Vor dem Hintergrund dieser Resultate sollte die inhaltliche Ausgestaltung
von BTM-Screenings zur Abstinenzkontrolle diskutiert werden.
Optimizing the number of valid measurements for the attenuation coefficient to assess hepatic steatosis in MAFLD patients: A study of 139 patients who underwent liver biopsy
Authors: Li Xueqi , Huang Xianjue , Cheng Guangwen , Liang Jing , Qiu Luping , Zhang Jubo , Yao Qiyuan , Ding Hong
Published: December 2023

Purpose We investigated the optimal number of valid measurements (VMs) for the attenuation coefficient (AC) to assess liver steatosis using attenuation imaging (ATI) and explored factors that may affect AC measurement in patients with metabolic dysfunction-associated fatty liver disease (MAFLD).

Materials and Methods A total of 139 patients with MAFLD who underwent ATI and liver biopsy were enrolled. Hepatic steatosis was graded as S0–3 according to the SAF scoring system. The AC values from 1, 2, 3, 5, and 7 VMs were compared with the degree of liver steatosis. The correlation between AC values from different VMs was analyzed. The diagnostic performance of AC from different VMs at each steatosis grade was compared. The factors related to AC were identified using linear regression analysis.

Results The mean AC values from 1, 2, 3, 5, and 7 VMs were not significantly different between grades S0–3 (p=n.s. for all). Bland-Altman analysis showed the mean difference in AC values of 3 VMs and 7 VMs was 0.003 dB/cm/MHz, which was smaller compared with 2 VMs, and close to 5 VMs. The intraclass correlation coefficients of AC were all > 0.90 among different VM groups. AC values from different VMs all significantly predicted steatosis grade ≥S1, ≥S2, and S3 without significant statistical differences (p=n.s. for all). The multivariate analysis showed that the hepatic steatosis grade and triglyceride level were factors independently associated with AC.

Conclusion Three valid measurements of AC may be adequate to ensure the accuracy and reproducibility of hepatic steatosis assessment. The degree of liver steatosis and the triglyceride level significantly affected AC values.
Recent Advances in Photoinduced Oxidative Cleavage of Alkenes
Authors: Parasram Marvin , Hussain Waseem A.
Published: December 2023

Oxidative cleavage of alkenes leading to valuable carbonyl derivatives is a fundamental transformation in synthetic chemistry. In particular, ozonolysis is the mainstream method for the oxidative cleavage of alkenes that has been widely implemented in the synthesis of natural products and pharmaceutically relevant compounds. However, due to the toxicity and explosive nature of ozone, alternative approaches employing transition metals and enzymes in the presence of oxygen and/or strong oxidants have been developed. These protocols are often conducted under harsh reaction conditions that limit the substrate scope. Photochemical approaches can provide milder and more practical alternatives for this synthetically useful transformation. In this review, we outline recent visible-light-promoted oxidative cleavage reactions that involve photocatalytic activation of oxygen via electron transfer and energy transfer. Also, an emerging field featuring visible-light-promoted oxidative cleavage under anaerobic conditions is discussed. The methods highlighted in this review represent a transformative step toward more sustainable and efficient strategies for the oxidative cleavage of alkenes.

1 Introduction

2 Photochemical Methods for Oxidative Cleavage of Alkenes under Aerobic Conditions

2.1 Transition-Metal-Catalyzed Oxidative Cleavage of Alkenes under Visible Light

2.2 Photopromoted Organocatalyzed Oxidative Cleavage of Alkenes

2.3 Oxidative Cleavage of Alkenes with Molecular Iodine under Visible Light

2.4 Polymer-Catalyzed Oxidative Cleavage under Visible Light Irradiation

2.5 Oxidative Cleavage via Direct Visible Light Excitation with Molecular Oxygen

3 Anaerobic Oxidative Cleavage of Alkenes under Visible Light

4 Conclusion
Power harmonic and inter-harmonic detection based on fractional wavelet transform combined with variational modal decomposition algorithm
Authors: Dou Jiawei , Yang Xiaoyu , Yang Xiaozhong
Published: December 2023

Aiming at the problem of present power harmonic and inter-harmonic detection methods, which are susceptible to noise interference and have low detection accuracy for inter-harmonics, a novel power harmonic and inter-harmonic detection method based on fractional wavelet transform (FRWT) combined with variational mode decomposition (VMD) is proposed. The FRWT-VMD algorithm first preprocesses the signal with FRWT and VMD. Second, the VMD is used to extract harmonics and inter-harmonics. The method incorporates the advantages of the FRWT and VMD methods, corrects the defect that the FRWT method is difficult to detect inter-harmonics, and improves the problem that the VMD method is susceptible to noise interference. Simulation tests on various power harmonic signals have shown that under low signal-to-noise ratio conditions, the FRWT-VMD algorithm can effectively reduce the impact of noise and has high accuracy in harmonic and inter-harmonic detection. It is a powerful method for detecting harmonics and inter-harmonics in power systems.
Adaptive integral alternating minimization method for robust learning of nonlinear dynamical systems from highly corrupted data
Authors: Zhang Tao , Liu Guang , Wang Li , Lu Zhong-rong
Published: December 2023

This paper proposes an adaptive integral alternating minimization method (AIAMM) for learning nonlinear dynamical systems using highly corrupted measured data. This approach selects and identifies the system directly from noisy data using the integral model, encompassing unknown sparse coefficients, initial values, and outlier noisy data within the learning problem. It is defined as a sparse robust linear regression problem. An adaptive threshold parameter selection method is proposed to constrain model fitting errors and select appropriate threshold parameters for sparsity. The robustness and accuracy of the proposed AIAMM are demonstrated through several numerical experiments on typical nonlinear dynamical systems, including the van der Pol oscillator, Mathieu oscillator, Lorenz system, and 5D self-exciting homopolar disc dynamo. The proposed method is also compared to several advanced methods for sparse recovery, with the results indicating that the AIAMM demonstrates superior performance in processing highly corrupted data.
An asymptotic expansion for the number of two-connected chord diagrams
Authors: Mahmoud Ali Assem
Published: December 2023

We derive a functional relation between the generating functions of connected chord diagrams and two-connected chord diagrams. This relation enables us to calculate an asymptotic expansion for the number of two-connected chord diagrams on n chords. The asymptotic information obtained from this expansion refines the last established results and provides a simple alternative for calculating the asymptotic behaviour of the certain functions in (zero-dimensional) quantum electro-dynamics.
Entrainment and bulk flow characteristics of heated and unheated transient plumes using direct numerical simulations
Authors: Khan Jalil ul Rehman , Rao Samrat
Published: December 2023

An off-source volumetrically heated turbulent transient plume, known as transient diabatic plume (TDP), is compared with an unheated transient plume (TP). Both the TDP and TP are simulated using direct numerical simulations at a source Reynolds number (Re) of 2000. The flow is sufficiently resolved till the Kolmogorov (η) scale. The radius of the TP shows a self-similar behavior of linear increase with height after about five diameters from the source hot-patch. However, the velocity does not show a self-similar behavior. The addition of off-source buoyancy in the TDP triples the vertical velocity and also causes an order of magnitude increase in the vorticity magnitude (ω) due to the effect of the baroclinic torque. Compared to the TP, the entrainment coefficient and radius of the TDP increase and this shows enhanced entrainment due to heating. The transient flows fields are analyzed using local scales based on integral quantities of volume, momentum, and buoyancy. Normalizing the vorticity with these integral scales results in a more uniform scaled ωl for both flows. Hence, for both TP and TDP, we use the same values of ωl to quantify the inner and outer boundaries of the turbulent non-turbulent layer (TNTL). The width of the TNTL (δTNTL) decreases by ∼25% due to heating. The conditionally averaged velocity profiles suggest that very close to the outer irrotational boundary (IB) of the TNTL, the TDP exhibits stronger updrafts and downdrafts in comparison to the TP. Entrainment is studied using the mean relative velocity (⟨vn⟩) defined at the IB. The analysis of the components of ⟨vn⟩ reveal that the viscous diffusion component, which is of the order of the Kolmogorov velocity (uη), is balanced by the baroclinic and viscous dissipation components, while the inviscid term is negligible in comparison.
Adsorption-induced transient friction of hydrogels on hydrophilic countersurfaces
Authors: Choi Jiho , Yang Kwangmo , Lee Youn-Ki , Lee Sungho , An Kunsik , Kim Sung-Soo , Kim Jiho
Published: December 2023

Soft hydrated permeable surfaces of hydrogels exhibit unique lubrication behaviors, including frictional hysteresis found in tribo-rheometry measurements. A hydrogel lubrication model that describes the transient behavior was previously developed using the structure kinetics model in the field of rheology and rate-and-state friction model, where the friction change is described as a competition between buildup and breakdown rates. In this study, the model is further modified to include the effect of hydrophilicity of a countersurface. Ultraviolet (UV)/ozone treatment on an aluminum surface significantly removes organic materials, resulting in extremely hydrophilic surface. Friction response of a polyacrylamide hydrogel against untreated and UV/ozone-treated aluminum exhibited noteworthy difference in the trajectory of hysteresis. Model fits were conducted using the modified lubrication model on both hystereses, and the fitting parameters of both hystereses are compared with each other to identify a parameter addressing hydrophilicity. Based on the model fits, we suggest that the hydrophilicity of the countersurface initially prevents the adsorption on the hydrogel surface because it holds water better. However, once water goes out of the contact due to contact pressure, a stronger adsorption occurs, which increases friction and decreases the speed dependence of friction.
Experimental and numerical study on the Izbash equation coefficients in rough single fractures
Authors: Xing Kun , Ma Lei , Qian Jiazhong , Ma Haichun , Deng Yaping
Published: December 2023

The Izbash equation has been widely used in the subsurface applications. However, the Izbash equation is still empirical, and its coefficients (scaling factor λ and power exponent M) have not been systematically characterized and quantified. In this study, laboratory experiments and numerical simulations of fluid flow across a wide range of hydraulic gradients (J = 0–4) in horizontal rough fractures were conducted to comprehensively characterize and quantify the influence of fracture geometric attributes and fluid inertial effects on λ and M. The results showed that λ increased with fracture relative roughness (RSD). The fluid inertial effect (quantified by the non-Darcy effect factor E and Re) had a two-stage influence on λ. When the fluid flow was laminar, λ increased with E. However, when the fluid flow regime starts to transition from laminar flow to turbulent flow, λ decreased with increasing E. M is positively correlated with RSD and the fluid inertia effect E. We found that the transition of flow regime from laminar to turbulent flow depended on whether the recirculation zones are fully developed. The fully developed recirculation zones determine the distortions of the velocity field and flow field, which induced the turbulent flow. The quantitative models of λ and M were obtained based on numerical simulations, which quantified the coupling influence of the fracture geometric property and fluid inertial effect. The validity of quantitative models was verified by laboratory experiments. Our work provided a new understanding of the Izbash coefficients and laid a foundation for theoretical background exploration of the Izbash equation.
Epitaxial lattice-matched AlScN/GaN distributed Bragg reflectors
Authors: van Deurzen L. , Nguyen T.-S. , Casamento J. , Xing H. G. , Jena D.
Published: December 2023

We demonstrate epitaxial lattice-matched Al0.89Sc0.11N/GaN 10 and 20 period distributed Bragg reflectors (DBRs) grown on c-plane bulk n-type GaN substrates by plasma-assisted molecular beam epitaxy. Resulting from a rapid increase in in-plane lattice coefficient as scandium is incorporated into AlScN, we measure a lattice-matched condition to c-plane GaN for a Sc content of just 11%, resulting in a large refractive index mismatch Δn greater than 0.3 corresponding to an index contrast of Δn/nGaN = 0.12 with GaN. The DBRs demonstrated here are designed for a peak reflectivity at a vacuum wavelength of 400 nm, reaching a reflectivity of 0.98 for 20 periods. It is highlighted that AlScN/GaN multilayers require fewer periods for a desired reflectivity than other lattice-matched Bragg reflectors such as those based on AlInN/GaN multilayers.
A global 2A″ state potential energy surface for the Al (2P) + O2 (Σg−3) → AlO (2Σ+) + O (3P) reaction based on the doubly hybrid functional XYG3
Authors: Chen Jun , Wang Fengyan , Xu Xin
Published: December 2023

In this paper, a global and full-dimensional potential energy surface at the 2A″ ground state for the Al + O2 → AlO + O reaction was constructed, for the first time, based on extensive electronic structure calculations using the doubly hybrid functional XYG3 and potential energy surface fittings by neural networks. Details of the reaction paths have been analyzed. It was found that both two intermediates, the cyclic-AlO2 and the linear-OAlO, were able to dissociate to the AlO + O products, and the isomerization process between these two intermediates was controlled by conical intersections between two 2A″ states. Ro-vibrational state resolved integral cross sections have also been calculated at collision energies from 1.0 to 10.0 kcal/mol. The results support the harpooning mechanism in this metal-oxidant-involved reaction.
Optimization of the efficiency of a nanowire solar cell by nanowire tapering
Authors: Bochicchio Emanuele , Korzun Ksenia , Dubach Friso , van Gorkom Bas T. , Theeuwes Roel J. , (Erwin) Kessels Wilhelmus M. M. , Rivas Jaime Gómez , Haverkort Jos E. M.
Published: December 2023

Thermodynamics shows that the open-circuit voltage (Voc) of a solar cell is dependent on the external radiative efficiency at Voc. In planar solar cells with low photon recycling probability, this efficiency is limited to 2% due to total internal reflection of the emitted light, providing a penalty of 101 mV to the Voc. Tapered nanowire solar cells allow for an adiabatic expansion of the guided optical mode into air, allowing to reduce this loss. For this purpose, we first perform simulations of the photon escape probability in tapered nanowires with both finite difference time domain simulations as well as with rigorous coupled-wave analysis, showing photon escape probabilities up to 47.2% for normally tapered nanowires and up to 92% for inversely tapered nanowires. We subsequently show that by fine tuning the recipe for reactive ion etching of the tapered InP nanowires, we can decrease the nanowire tapering angle from 4.5° down to 1.8°, allowing to significantly increase the measured external radiative efficiency. We finally observe an open-circuit voltage of 0.746 V at a tapering angle of 2.46°.
On the internal velocity structure of sub-aqueous, gravity-driven granular flow: Measurements using MHz frequency sound
Authors: Hare Jenna , Hay Alex E.
Published: December 2023

The vertical structure of downslope velocity within sub-aqueous gravity-driven flows of (smoother) glass beads and (rougher) natural sand is investigated for both fixed roughness and erodible beds using high-resolution, MHz-frequency acoustics. The observed velocity profiles within the O(1) cm thick, O(10) cm/s flows exhibit a negative shear layer extending downward from the sediment–water interface to a velocity maximum at ∼ 9 grain diameters depth within the layer, below which the velocities decrease to near-zero values at the pre-flow bed location for fixed roughness beds and to non-zero values for mobile beds. The attenuation of sound transmitted through the moving layer is used to constrain the depth-averaged solids concentration to a value of ∼ 0.52. The observed negative shear at the interface indicates that, unlike the sub-aerial case, interfacial friction is dynamically important in gravity-driven sub-aqueous granular flows. It is shown that the observed vertical structure of velocity within the layer can be well represented by continuum viscous flow models. Solids concentration and effective viscosity are estimated from the best-fit model parameters using the Zarraga–Hill–Leighton (2000) empirical relation for suspensions of negatively buoyant particles, yielding vertically averaged values ∼ 0.57. While the sub-millimeter vertical resolution of the measurements is too coarse to provide precise estimates of the friction velocity at the interface, the model-data comparisons nevertheless indicate that the vertical structure of the downslope flow consists of a weakly stratified dense layer and a thin, dilute transition layer between the dense flow and the overlying water.
Sustainable early-stage lasing in a low-emittance electron storage ring
Authors: Zhou Kaishang , Li Renkai , Bai Zhenghe
Published: December 2023

In this Letter, we report on the concept and analysis of a low-emittance electron storage ring, in which the electron beams undergo an early-stage self-amplified spontaneous emission lasing process on a turn-by-turn basis. The lasing process for each pass through a long undulator in the ring is terminated when the radiated power is still negligible compared to the total synchrotron loss of each circulation, and the electron beams can be maintained in an equilibrium state that supports sustainable lasing. A self-consistent model is derived for evaluation of the properties of the electron beams, and a design with numerical modeling is presented that demonstrates the feasibility of generating short wavelength radiation at the kW power level.
Prospect of optical chirality logic computing
Authors: Zhang Yi , Arias-Muñoz Juan C. , Cui Xiaoqi , Sun Zhipei
Published: December 2023

In this Perspective, we summarize the current state-of-the-art and the challenges of optical chirality logic computing. We discuss the prospects of its applications in integrated photonics, quantum technologies, and other multifunctional optoelectronics for ultrafast data processing.
Perspective on defect control in semiconductors for photovoltaics
Authors: Cai Xuefen , Wei Su-Huai
Published: December 2023

Harnessing the boundless solar energy, photovoltaic cells emerge as pivotal players in the world’s sustainable energy landscape. The efficiency of solar cells is intimately tied to the carrier properties influenced by defects and impurities within the sunlight-absorbing semiconductors. In this Perspective, we offer a brief overview of recent advances in exploring doping properties with a focus on three vital thin-film photovoltaic semiconductors: CdTe, CIGS, and halide perovskites. Our discourse encompasses their electronic band structure, intrinsic and extrinsic doping behaviors, defect-assisted nonradiative recombination losses, as well as promising strategies poised to enhance solar cell efficiency. Additionally, we discuss several lingering challenges associated with defects in the advancement of photovoltaic technologies.
Efficient THz generation from low-temperature-grown GaAs photoconductive antennas driven by Yb-doped fiber amplifier at 200 kHz repetition rate
Authors: Nilforoushan N. , Kidd C. , Fournier A. , Palomo J. , Tignon J. , Dhillon S. , Lhuillier E. , Li Lianhe , Davies A. Giles , Linfield E. H. , Freeman J. R. , Mangeney J.
Published: December 2023

We demonstrate the generation of terahertz (THz) pulses with electric field strength reaching 34 kV/cm from low-temperature-grown GaAs (LT-GaAs) interdigitated photoconductive antennas driven by 1030 nm optical pulses delivered by a commercial ytterbium-doped fiber laser operating at a repetition rate of 200 kHz. By probing the Urbach absorption in LT-GaAs layers, we show that the THz generation mechanism predominantly relies on the photoexcitation of electrons from the valence band to shallow defect states arising from the incorporation of excess As during the growth process. Our THz source opens the route toward nonlinear time-resolved study of low-energy excitations in matter with high signal-to-noise ratios.
Entropy-driven optimization of radiative Jeffrey tetrahybrid nanofluid flow through a stenosed bifurcated artery with Hall effects
Authors: Kumar Sharma Bhupendra , Gandhi Rishu
Published: December 2023

Atherosclerosis, which causes the artery walls to thicken, the lumen to narrow, and the wall to thin in some places, is characterized by plaque accumulation in the arteries. These blood flow modifications can cause aneurysms and heart attacks if left unattended. Most of the arteries in the cardiovascular system are branched; therefore, a parent artery (main artery) with two daughter arteries (branched arteries) is considered in the present analysis. To examine the impact of various nanoparticle combinations on blood flow, four distinct nanoparticles, namely, gold (Au), graphene oxide (GO), copper (Cu), and tantalum (Ta), were injected into the blood to generate Au–GO–Cu–Ta/blood tetrahybrid nanofluid. In arteries with small diameters, blood behavior is regarded as non-Newtonian; therefore, blood behavior is governed by Jeffrey fluid in the present analysis. It has been investigated how Hall effects, Joule heating, radiation, and viscous dissipation affect blood flow through an artery that has an overlapping stenosis in the branches and a bell-shaped stenosis in the main artery. The approximation of mild stenosis is utilized to simplify and non-dimensionalize the governing equations. The Crank–Nicolson finite-difference scheme is used in MATLAB to solve the resulting equations. The results for velocity, temperature, wall shear stress, flow rate, and heat transfer rate are represented graphically. Furthermore, the entropy optimization has been performed for the specified problem. Enhancement in velocity with half of the bifurcation angle (η) can be observed from the velocity contours. The velocity of the tetrahybrid nanofluid increases with an increase in Jeffrey fluid parameter (λ1*) and shape parameter of the nanoparticles (n) as well. Introducing nanoparticles into the bloodstream can improve targeted drug delivery, allowing for more precise treatment at the cellular level. In addition, the tunable properties of nanoparticles offer possibilities for enhanced therapeutic and diagnostic treatments in a variety of medical disorders.
In situ annealing of nanoporous silicon thin films with transmission electron microscopy
Authors: Li Qin-Yi , Medina Fabian Javier , Kokura Kosuke , Jin Zheyu , Takahashi Koji , Hao Qing
Published: December 2023

Nanoporous films have potential applications in thermoelectric cooling on a chip, sensors, solar cells, and desalination. For phonon transport, amorphization and other pore-edge defects introduced by the nanofabrication processes can eliminate wave effects by diffusively scattering short-wavelength phonons and thus destroying the phonon phase coherence. As a result, phononic effects can only be observed at 10 K or below, when long-wavelength phonons become dominant for thermal transport. In this work, a 70-nm-thick silicon thin film with approximately 100-nm-diameter nanopores was annealed under a high vacuum, and the change of pore-edge defects was observed with in situ transmission electron microscopy. It was found that the pore-edge defects can be minimized to a sub-1-nm layer by annealing between 773 and 873 K for 30 min, without changing the pore sizes. The largely reduced pore-edge defects are critical to the desired phonon wave effects within a periodic nanoporous structure.
Multidimensional uniform semiclassical instanton thermal rate theory
Authors: Pollak Eli
Published: December 2023

Instanton-based rate theory is a powerful tool that is used to explore tunneling in many-dimensional systems. Yet, it diverges at the so-called “crossover temperature.” Using the uniform semiclassical transmission probability of Kemble [Phys. Rev. 48, 549 (1935)], we showed recently that in one dimension, one might derive a uniform semiclassical instanton rate theory, which has no divergence. In this paper, we generalize this uniform theory to many-dimensional systems. The resulting theory uses the same input as in the previous instanton theory, yet does not suffer from the divergence. The application of the uniform theory to dissipative systems is considered and used to revise Wolynes’ well-known analytical expression for the rate [P. G. Wolynes, Phys. Rev. Lett. 47, 968 (1981)] so that it does not diverge at the “crossover temperature.”
Effects of substrate on the nanoscale friction of graphene
Authors: Wang Wen , Zhang Yu , Wang Ashu
Published: December 2023

In the realm of nanotechnology, atomically thin two-dimensional graphene has garnered attention for its impeccable hexagonal physical structure and chemically inert surface properties. These attributes endow graphene with remarkable mechanical, physical, and chemical characteristics, positioning it as one of the ideal solid lubricants for mitigating friction and wear at contact interfaces. However, the performance of graphene is intricately linked to the substrate it interacts with. Consequently, an in-depth investigation of how substrate variations impact graphene's friction behavior assumes paramount significance in the realm of industrial applications. This study delves into the intricate dynamics of graphene friction through atomic force microscopy experiments, focusing on three pivotal aspects: the binding strength between graphene and the substrate, the Young’s modulus of the substrate, and substrate materials. By subjecting the SiO2/Si substrate to plasma treatment to augment its surface energy, we enhance the interface binding strength between the substrate and graphene, thereby diminishing friction on the graphene surface. Furthermore, we investigate how graphene responds to various substrates, including polypropylene carbonate films of varying Young’s modulus, as well as graphite, h-BN, and SiO2/Si substrates. Graphene demonstrates a pronounced inclination toward increased friction when interfacing with substrates characterized by lower Young's modulus, higher roughness, and adhesion. These findings elucidate the potential for fine-tuning friction in lamellar materials, underscoring the pivotal role of comprehending nanoscale friction dynamics on graphene surfaces.
Strain and stacking induced topological phase transition in bipolar ferromagnetic semiconductor OsClBr
Authors: Li Congling , Chen Hongxin , Hu Guichao , Yuan Xiaobo , Ren Junfeng , Zhao Xiuwen
Published: December 2023

The combination of valleytronics and topology has great potential significance in condensed matter and material physics. Here, based on first-principles calculations, we predict a dipolar ferromagnetic semiconductor OsClBr. Benefiting from strong spin–orbit coupling and the intrinsic exchange interaction of localized d electrons, spontaneous valley polarization occurs. In addition, the tensile strain can induce topological phase transitions between ferrovalley, half-valley-metal, and valley-polarization quantum anomalous Hall (VQAH) phases, which can be attributed to the band inversion between dz2 and dxy/dx2−y2 orbitals of Os atom. Moreover, stacking-dependent topological phase transitions can be found in bilayer OsClBr, and the robustness of VQAH phase in b − 1 configuration under a wide strain range has been proved, which is greatly beneficial for the regulation of quantum states. Our work provides a potential opportunity for the preparation and application of low-power consumption electronics devices.
Common leaf spot of lucerne and the dawn of mycology and plant pathology in Australia
Authors: Ryley Malcolm J.
Published: December 2023

As the number of livestock increased in the years following English colonisation of Australia in 1788, the need for nutritious fodder, including lucerne (Medicago sativa), grew. One of the first diseases found on lucerne was a leaf spot which was collected in 1879 by George Bancroft, a physician and naturalist, in a suburb of Brisbane. The Queensland Government Botanist Frederick Manson Bailey sent a specimen to the prominent English mycologists Miles Joseph Berkeley and Christopher Edmund Broome who in 1883 formally described and named the fungus Sphaerella destructiva. That fungus is now known as Pseudopeziza medicaginis, the causal agent of common leaf spot of lucerne. It was one of over 300 fungi that were included in a 1880 paper co-written by the Reverend Julian Tenison-Woods and Frederick Bailey. At that time almost all of these fungi which had been collected in Australia were identified by overseas mycologists, particularly Berkeley and Broome. It can be argued that their 1880 paper was the first significant one published in Australia which focussed on fungi. Just a decade or so later Australian scientists, in particular Daniel McAlpine, were describing new fungal taxa on their own.
The neuropeptide drosulfakinin enhances choosiness and protects males from the aging effects of social perception
Authors: Fedina Tatyana Y. , Cummins Easton T. , Promislow Daniel E. L. , Pletcher Scott D.
Published: December 2023

The motivation to reproduce is a potent natural drive, and the social behaviors that induce it can severely impact animal health and lifespan. Indeed, in
Drosophila
males, accelerated aging associated with reproduction arises not from the physical act of courtship or copulation but instead from the motivational drive to court and mate. To better understand the mechanisms underlying social effects on aging, we studied male choosiness for mates. We found that increased activity of insulin-producing cells (IPCs) of the fly brain potentiated choosiness without consistently affecting courtship activity. Surprisingly, this effect was not caused by insulins themselves, but instead by drosulfakinin (DSK), another neuropeptide produced in a subset of the IPCs, acting through one of the two DSK receptors, CCKLR-17D1. Activation of

Dsk
+

IPC neurons also decreased food consumption, while activation of

Dsk
+

neurons outside of IPCs affected neither choosiness nor feeding, suggesting an overlap between

Dsk
+

neurons modulating choosiness and those influencing satiety. Broader activation of

Dsk
+

neurons (both within and outside of the IPCs) was required to rescue the detrimental effect of female pheromone exposure on male lifespan, as was the function of both DSK receptors. The same broad set of

Dsk
+

neurons was found to reinforce normally aversive feeding interactions, but only after exposure to female pheromones, suggesting that perception of the opposite sex gates rewarding properties of these neurons. We speculate that broad

Dsk
+

neuron activation is associated with states of satiety and social experience, which under stressful conditions is rewarding and beneficial for lifespan.
Ring-opening metathesis polymerization of
N
-methylpyridinium-fused norbornenes to access antibacterial main-chain cationic polymers
Authors: Hancock Sarah N. , Yuntawattana Nattawut , Diep Emily , Maity Arunava , Tran An , Schiffman Jessica D. , Michaudel Quentin
Published: December 2023

Cationic polymers have been identified as a promising type of antibacterial molecules, whose bioactivity can be tuned through structural modulation. Recent studies suggest that the placement of the cationic groups close to the core of the polymeric architecture rather than on appended side chains might improve both their bioactivity and selectivity for bacterial cells over mammalian cells. However, antibacterial main-chain cationic polymers are typically synthesized via polycondensations, which do not afford precise and uniform molecular design. Therefore, accessing main-chain cationic polymers with high degrees of molecular tunability hinges upon the development of controlled polymerizations tolerating cationic motifs (or cation progenitors) near the propagating species. Herein, we report the synthesis and ring-opening metathesis polymerization (ROMP) of
N
-methylpyridinium-fused norbornene monomers. The identification of reaction conditions leading to a well-controlled ROMP enabled structural diversification of the main-chain cationic polymers and a study of their bioactivity. This family of polyelectrolytes was found to be active against both Gram-negative (
Escherichia coli
) and Gram-positive (Methicillin-resistant
Staphylococcus aureus
) bacteria with minimal inhibitory concentrations as low as 25 µg/mL. Additionally, the molar mass of the polymers was found to impact their hemolytic activity with cationic polymers of smaller degrees of polymerization showing increased selectivity for bacteria over human red blood cells.
Ozonolysis can produce long-lived greenhouse gases from commercial refrigerants
Authors: McGillen Max R. , Fried Zachary T. P. , Khan M. Anwar H. , Kuwata Keith T. , Martin Connor M. , O’Doherty Simon , Pecere Francesco , Shallcross Dudley E. , Stanley Kieran M. , Zhang Kexin
Published: December 2023

Hydrofluoroolefins are being adopted as sustainable alternatives to long-lived fluorine- and chlorine-containing gases and are finding current or potential mass-market applications as refrigerants, among a myriad of other uses. Their olefinic bond affords relatively rapid reaction with hydroxyl radicals present in the atmosphere, leading to short lifetimes and proportionally small global warming potentials. However, this type of functionality also allows reaction with ozone, and whilst these reactions are slow, we show that the products of these reactions can be extremely long-lived. Our chamber measurements show that several industrially important hydrofluoroolefins produce CHF
3
(fluoroform, HFC-23), a potent, long-lived greenhouse gas. When this process is accounted for in atmospheric chemical and transport modeling simulations, we find that the total radiative effect of certain compounds can be several times that of the direct radiative effect currently recommended by the World Meteorological Organization. Our supporting quantum chemical calculations indicate that a large range of exothermicity is exhibited in the initial stages of ozonolysis, which has a powerful influence on the CHF
3
yield. Furthermore, we identify certain molecular configurations that preclude the formation of long-lived greenhouse gases. This demonstrates the importance of product quantification and ozonolysis kinetics in determining the overall environmental impact of hydrofluoroolefin emissions.
Literary back-translation, mistranslation, and misattribution
Authors: Washbourne Kelly
Published: December 2023

This study seeks a threefold exploration of an aspect of Mark Twain’s forays into translation, particularly with
respect to one tale’s fate in its first French version. First, back-translation’s most ostensible purpose is to represent a
foreign language text’s (in)accuracy transparently; Twain, assuming a persona as a naive mistranslator, humorously reinvents the
procedure to disparage a rendering of his work, constituting an act of translation (meta)criticism and producing a work of parody.
The study turns to literary back-translation as an emerging horizon of translation “against our teleological conception of
translation” (Lane 2020a, 6), and a potential source of creative misprision or
misreading. Twain uses literalism, I demonstrate, as a comic strategy to confound sense. I show cases in which Twain indulged in
pseudotranslation and free-associational mistranslation often as imaginative perspective-taking. Secondly, I survey the intrigue
behind his famous back-translation of the jumping frog tale, including its textual variations, and locate it as a subversion.
Thirdly and finally, I perform a comparative reading of representative passages from Twain’s story, the 19th-century translation
by Theodor Bentzon (actually Marie-Thérèse Blanc), and Twain’s vengeful back-translation, in order to reveal patterns of the
American writer’s translation technique.
Green Recovery and Regenerative Tourism: The Success Story of Miso Walai Homestay in Building a Resilient Rural Tourism Destination
Authors: Hosen Nadzirah , Paulino Isabel , Hamzah Amran
Published: December 2023

Although green recovery and regenerative tourism are well-documented in the literature, case studies at the destination level are lacking, and this is because the application of these concepts is still in its early stages. Therefore, this case study examines a rural tourism community in Lower Kinabatangan, Sabah (Malaysia). The authors used longitudinal analysis from 2007 to 2019, semi-structured interviews, and participant observations to illustrate how the area has managed to successfully recover from intense deforestation following years of exploitation by timber companies and also cushion the impact of COVID-19. The community pushed for a recovery agenda based on community-based ecotourism and green recovery, which resulted in the growth of regenerative tourism. This study examines how the community has seized new opportunities through ecotourism at Miso Walai Homestay, linked to a community forest-restoration programme, and how these opportunities were intensified during the COVID-19 pandemic to compensate for the lack of tourists. Consequently, this case study shows how Miso Walai Homestay has become a model of a regenerative approach that promotes a resilient rural tourism destination. Key success factors have been the agile community leadership, an early start in community forest restoration, partnerships with volunteer organizations, the establishment of trust and reputation, the promotion of citizen science, and the embrace of green recovery initiatives.

This case highlights the success of Miso Walai Homestay in leveraging green recovery initiatives to cushion the financial impact of two situations. First, after the withdrawal of the timber companies from the Kinabatangan region (Malaysia), a new model of community-based tourism was established through a community forest restoration programme. Second, during the lockdown period of the COVID-19 pandemic, income streams were consolidated from green recovery. The Miso Walai Homestay enjoyed a subsequent recovery stage in tandem with the gradual return of international tourists.

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