bluuebunny/crossref_metadata_2025 huggingface dataset:
C-Peptid als Surrogatparameter einer residualen Beta-Zellfunktion bei Typ-1-Diabetes und ihre mögliche klinische Bedeutung
Authors: Müller-Wieland Dirk , Miszon Martin , Dunstheimer Désirée , Forst Thomas , Kapellen Thomas Michael , Schnell Oliver , Kellerer Monika
Published: December 2024

C-Peptid, ein Molekül, welches in äquimolarer Konzentration zu Insulin produziert wird, hat sich als Biomarker für die Insulinsekretion bei Menschen mit Typ-1-Diabetes etabliert. Die Messung des C-Peptidspiegels kann in der klinischen Praxis hilfreich sein, um die Restfunktion der insulinproduzierenden β-Zellen zu beurteilen, insbesondere bei Menschen unter Insulintherapie. Sinkende C-Peptidwerte spiegeln dabei eine Verschlechterung der β-Zellfunktion wider. Während die C-Peptid-Sekretion in den ersten Monaten nach Diagnosestellung des Typ-1-Diabetes ein zuverlässiger Prädiktor für eine klinische Teilremission sein kann, gibt es zunehmend Hinweise auf eine persistierende β-Zellfunktion bei Menschen mit langjährigem Typ-1-Diabetes. Bei der Mehrzahl der Menschen mit langjährigem Typ-1-Diabetes ist C-Peptid auch in geringen Mengen nachweisbar, insbesondere wenn hochempfindliche Assays verwendet werden. Trotz erheblicher Fortschritte in der Insulintherapie erreichen in Deutschland nur etwa 44% der Menschen mit Typ-1-Diabetes eine ausreichende Glukoseeinstellung, um Langzeitkomplikationen zu vermeiden. Die Verbesserung der Überlebensrate der verbleibenden β-Zellen, gemessen an der erhaltenen C-Peptid-Konzentration, steht im Mittelpunkt vieler krankheitsmodifizierender Studien. Eine krankheitsmodifizierende Therapie zur Erhaltung der β-Zellfunktion könnte eine alternative oder ergänzende Behandlungsoption zur Insulintherapie bei Typ-1-Diabetes darstellen. Ziel dieser Übersichtsarbeit ist es, die Bedeutung des C-Peptids und seine Rolle bei der Diagnose, Überwachung und Behandlung des Typ-1-Diabetes darzustellen.
Surgical Anatomy of the Retrosigmoid Approach with Endoscopic-Assisted Reverse Anterior Petrosectomy: Optimizing Meckel's Cave Access from the Posterior Fossa
Authors: De Bonis Alessandro , Torregrossa Fabio , Dang Danielle D. , Leonel Luciano César P. C. , Mortini Pietro , Link Michael , Colin Driscoll , Peris-Celda Maria
Published: December 2024

Objectives We investigated the extent of access to Meckel's cave (MC) and the middle cranial fossa (MCF) protecting the internal carotid artery (ICA) using the retrosigmoid approach with endoscopic-assisted reverse anterior petrosectomy (EA-RAP).

Methods Five specimens were dissected using the limited and extended EA-RAP. Based on the bone removal of the internal acoustic meatus (IAM) and subarcuate fossa, exposure of the MC and ICA were statistically compared.

Results The limited and extended EA-RAP allowed access to the medial and anterior MC (4 mm posterior to the first genu of the cavernous ICA, and 20 mm posterior to foramen rotundum [FR]). The access to the lateral MC varied with distance of 12 and 8 mm medial to the foramen ovale for the limited and extended EA-RAP, respectively.

In the extended EA-RAP, the exposure of the ICA was gained by drilling with the 0-degree endoscope (3 mm) versus 45-degree endoscope (9 mm). The working distances from the midpoint of the IAM to the most medial point of the exposed ICA was 24 mm. The most lateral point of the exposed ICA varied between 0- and 45-degree endoscopes with a distance of 21 and 13 mm, respectively.

Conclusion A coronal plane from the posterior genu of the cavernous ICA and a sagittal plane to the common crus of the semicircular canals can define the area of MCF accessed by the EA-RAP. Drilling of the temporal bone should be carefully customized according to the patient and can be aided by endoscopic assistance for direct visualization to minimize the risk of injuries to ICA.
Synthesis of Cyclic Diglycerols: The Utility of the BF3·OEt2-Mediated Intramolecular Epoxide Ring-Opening Reaction for the Cyclic Polyglycerol Synthesis
Authors: Hamada Masahiro , Noda Mizuki , Saeki Yu , Nakajima Noriyuki
Published: December 2024

We report the synthesis of cyclic diglycerols, which are the smallest repeating units in polyglycerols. Linear diglycerol epoxy alcohols are treated with a catalytic amount of boron trifluoride–diethyl ether complex (BF3·OEt2) in highly dilute dichloromethane (CH2Cl2) to give the corresponding 1,4-dioxepane- and 1,4-dioxane-type cyclic diglycerols in high yields as single structural isomers. The structures of the cyclic products are determined by 1D and 2D NMR spectral analysis. The observed results indicate that the cyclizations are consistent with Baldwin’s rules. The synthesized cyclic diglycerols can serve as standards for further studies.
Dengue and severe dengue with neurological complications: a challenge for prevention and control
Authors: Francelino Emanuelle de Oliveira , Puccioni-Sohler Marzia
Published: December 2024

Dengue is the main urban arbovirus in the Americas. The disease manifests in a varied spectrum: from asymptomatic cases to those with neurological involvement, which is considered a severe form of the disease. Its annual reemergence represents a serious public health problem. The rise in the number of cases causes an increase in the number of patients with neurological manifestations of the disease, which can range from headaches to more serious conditions such as encephalitis and Guillain-Barré syndrome, with high potential of death or sequelae. Dengue prevention and control strategies should also be a concern for neurologists. The aim of the present study is to carry out a narrative review of the current methods to prevent dengue fever and its severe forms, such as cases with neurological complications. The main control measures include vaccination, which is still carried out on a small scale, vector control, and individual protection. The CYD-TDV/Dengvaxia and TAK-003/DENVax vaccines, licensed for use by the Brazilian National Health Regulatory Agency (Agência Nacional de Vigilância Sanitária, ANVISA, in Portuguese), show efficacy against hospitalizations of 72.7% (95% confidence interval [95%CI]: 62.3–80.3%) and of 90.4% (95%CI: 82.6–94.7%) respectively. The TV003/TV005 vaccine, which is being studied by Intituto Butantan in Brazil, shows promising results, with an efficacy of 79.6% for symptomatic dengue. Vector control is based on biotechnological and behavioral measures, as well as on the improvement of basic sanitation conditions. The main individual protection measure is the use of topical repellents (icaridin). All of these actions represent important tools for the prevention of dengue fever and its neurological complications.
On the semiclassical limit of the Schrödinger-Lohe model and concentration estimates
Authors: Ha Seung-Yeal , Hwang Gyuyoung , Kim Dohyun
Published: December 2024

We study the semiclassical limit of quantum synchronization model and concentration estimates for the resulting limit model. From the Schrödinger-Lohe model, we rigorously derive the Vlasov-Lohe model using Wigner transform and Wigner measure method. In semiclassical limit, generalized Wigner distributions to the Schrödinger-Lohe model converge to a set of Wigner measures which corresponds to a weak solution to the Vlasov-Lohe model, and then we show the asymptotic collective behaviors of the Vlasov-Lohe model. When one-body potentials are identical, we show that complete synchronization emerges for the Vlasov-Lohe model. In contrast, for non-identical potentials the lack of boundedness results in practical synchronization for the integrals of solutions. Moreover, we construct a global existence of classical solutions to the Vlasov-Lohe model using the standard method of characteristics. Analysis in this work can deal with possibly non-identical potentials in which their differences are constant.
Miniaturized electrophoresis: An integrated microfluidic cartridge with functionalized hydrogel-assisted LAMP for sample-to-answer analysis of nucleic acid
Authors: Kumar Natish , Kumari Monika , Chander Devtulya , Dogra Sandeep , Chaubey Asha , Arun Ravi Kumar
Published: December 2024

Accurate detection of pathogenic nucleic acids is crucial for early diagnosis, effective treatment, and containment of infectious diseases. It facilitates the timely identification of pathogens, aids in monitoring disease outbreaks, and helps prevent the spread of infections within healthcare settings and communities. We developed a multi-layered, paper-based microfluidic and miniaturized electrophoresis system for rapid nucleic acid extraction, separation, amplification, and detection, designed for resource-limited settings. Constructed from acrylic, transparency film, pressure-sensitive adhesion, and Whatman paper using a CO2 laser, the setup simplifies traditional methods and eliminates the need for complex equipment. DNA extraction and purification are achieved using Zweifach–Fung bifurcation and Fahraeus effect principles, with detection via a hydrogel-assisted colorimetric isothermal reverse transcriptase-loop-mediated isothermal amplification technique. The system accurately identified the SARS-CoV-2 N-gene and β-actin human gene, validated by a compact electrophoresis setup. In clinical validation with 12 patient specimens, the system demonstrated a positive predictive agreement of 83.0% and a negative predictive agreement of 100%. The system achieves a limit of detection of 1 copy/μl and can potentially transform nucleic acid detection assays in healthcare settings. This study addresses key challenges in nucleic acid detection, such as ensuring sample quality and quantity, reducing reliance on sophisticated equipment, preventing contamination, simplifying procedures, and providing rapid and accurate diagnostics for emerging pathogens.
Investigation of a fast gate driver based on a half-turn planar transformer
Authors: Li Diangeng , Zhang Zicheng , Gao Jingming , Wang Lei , Sun Yijie , He Juntao
Published: December 2024

This paper presents a magnetically isolated gate driver for the fast switching of IGBT (Insulated Gate Bipolar Transistor) in compact pulsed power sources with sharp rising edges and flat-top pulses for the application of electromagnetic launch and food processing. The proposed gate driver is implemented based on a planar transformer with a half-turn winding arrangement to increase the amplitude of the driving voltage pulse. With the half-turn winding arrangement, the leakage inductance of transformers decreases by 31.1% compared to the interleaving structure. This decrease enables a fast rise time of the driving voltage pulse. Furthermore, the gate drivers are used to drive the IGBT switching a Blumlein pulse forming network. The results show that the di/dt of the applied commercially available Si IGBT is about 10.10 A/ns with a gate voltage of 50 V and a gate capacitance charging time of about 88 ns, proving the effectiveness of the gate driver and providing a high-performance driving scheme for the fast switching of Si IGBT.
A simple graphics processing unit-accelerated propagation routine for laser pulses in the strong-field regime
Authors: Martínez de Velasco A. , Eikema K. S. E.
Published: December 2024

We present a simple and easy-to-implement Graphics Processing Unit (GPU)-accelerated routine to numerically simulate the propagation of ultrashort and intense laser pulses as they interact with a medium. The routine is based on the solution of Maxwell’s wave equation in the frequency domain with an extended Crank–Nicolson algorithm implemented in the Nvidia CUDA C++ programming language. The main advantages of our method are its significant speed-up factor and its ease of implementation, requiring only basic knowledge of CUDA and C++. In this article, we review the strong-field wave equations to be solved and their discretization and demonstrate how to implement a numerical solver for them on an Nvidia GPU. We show the results of the simulation of a near-infrared laser pulse propagating through a partially ionized atomic gas and discuss the performance of our GPU-accelerated scheme. Compared to a naïve central processing unit implementation of the same routine, our GPU-accelerated version is up to 198 times faster in standard regimes.
Betavoltaic rechargeable Zn-ion battery based on hybrid cathode by combining betavoltaic structure with intercalation host
Authors: Ding Zan , Luo Zexiang , San Haisheng , Li Xue , Zhang Lifeng
Published: December 2024

To address the issue of low power output of betavoltaic cells in practical applications, a 63Ni-powered betavoltaic rechargeable Zn-ion battery (BRZiB) is presented in this paper for simultaneously harvesting, converting, and storing beta-radioactive energy within one device. Experimentally, a patterned ZnO microrod array nanostructure was prepared using hydrothermal and lithography methods, in which a 63Ni beta source was deposited by chemical plating to form a 63Ni@ZnO structure for betavoltaic power generation. A carbon-coated VO2 nanocomposite (C@VO2), used as the intercalation host for Zn ions, was coated on the betavoltaic structure for fabricating the hybrid cathode of BRZiB. Without using any external power source, the 63Ni-powered BRZiB demonstrated a voltage rise of 0.3 V in 82 h, which was calculated to have an energy conversion efficiency of 5.1% and an energy density of 128 mWh/g over a half-life of 63Ni (∼100 years). The experimental results verify the effectiveness of multi-energy synergistic conversion in the electrochemical betavoltaic system.
Fast and spectrally accurate construction of adaptive diagonal basis sets for electronic structure
Authors: Lindsey Michael , Sharma Sandeep
Published: December 2024

In this article, we combine the periodic sinc basis set with a curvilinear coordinate system for electronic structure calculations. This extension allows for variable resolution across the computational domain, with higher resolution close to the nuclei and lower resolution in the inter-atomic regions. We address two key challenges that arise while using basis sets obtained by such a coordinate transformation. First, we use pseudospectral methods to evaluate the integrals needed to construct the Hamiltonian in this basis. Second, we demonstrate how to construct an appropriate coordinate transformation by solving the Monge–Ampére equation using a new approach that we call the cyclic Knothe–Rosenblatt flow. The solution of both of these challenges enables mean-field calculations at a cost that is log-linear in the number of basis functions. We demonstrate that our method approaches the complete basis set limit faster than basis sets with uniform resolution. We also emphasize how these basis sets satisfy the diagonal approximation, which is shown to be a consequence of the pseudospectral method. The diagonal approximation is highly desirable for the solution of the electronic structure problem in many frameworks, including mean field theories, tensor network methods, quantum computing, and quantum Monte Carlo.
Enhancing up-conversion luminescence in Yb/Er co-doped CsPbCl3 single crystals
Authors: Muzyka T. M. , Pushak A. S. , Furgala Y. M. , Malynych S. Z. , Moroz I. E. , Kotlov A. , Demkiv T. M. , Voloshinovskii A. S. , Gamernyk R. V.
Published: December 2024

The search for and fabrication of materials for the near-infrared range of the spectrum, including telecommunication windows, is an extremely important task in modern technology. This work presents the results of studies on the photoluminescence of CsPbCl3 single crystals with varying contents of ytterbium and erbium impurities, grown using the Bridgman method. The existence of electrically neutral Yb3+–VPb–Er3+ complexes within the crystal structure was confirmed. Resonant absorption of excitation radiation λ = 980 nm by Yb3+ ions reveals a three-step energy transfer channel from Yb3+ to Er3+ ions within a single complex. The estimated quantum yield of up-conversion luminescence at λ = 524 nm (0.02%) associated with erbium ions indicates the presence of electronic transitions to higher energy levels, with the possibility of subsequent emission within the third telecommunication window.
Parrondo’s effects with aperiodic protocols
Authors: Pires Marcelo A. , Pinto Erveton P. , da Silva Rone N. , Duarte Queirós Sílvio M.
Published: December 2024

In this work, we study the effectiveness of employing archetypal aperiodic sequencing—namely, Fibonacci, Thue–Morse, and Rudin–Shapiro—on the Parrondian effect. From a capital gain perspective, our results show that these series do yield a Parrondo’s paradox with the Thue–Morse based strategy outperforming not only the other two aperiodic strategies but benchmark Parrondian games with random and periodical (AABBAABB…) switching as well. The least performing of the three aperiodic strategies is the Rudin–Shapiro. To elucidate the underlying causes of these results, we analyze the cross correlation between the capital generated by the switching protocols and that of the isolated losing games. This analysis reveals that a strong anticorrelation with both isolated games is typically required to achieve a robust manifestation of Parrondo’s effect. We also study the influence of the sequencing on the capital using the lacunarity and persistence measures. In general, we observe that the switching protocols tend to become less performing in terms of the capital as one increases the persistence and, thus, approaches the features of an isolated losing game. For the (log-)lacunarity, a property related to heterogeneity, we notice that for small persistence (less than 0.5), the performance increases with the lacunarity with a maximum around 0.4. In respect of this, our work shows that the optimization of a switching protocol is strongly dependent on a fine-tuning between persistence and heterogeneity.
relentless: Transparent, reproducible molecular dynamics simulations for optimization
Authors: Sreenivasan Adithya N , Petix C. Levi , Sherman Zachary M. , Howard Michael P.
Published: December 2024

relentless is an open-source Python package that enables the optimization of objective functions computed using molecular dynamics simulations. It has a high-level, extensible interface for model parameterization; setting up, running, and analyzing simulations natively in established software packages; and gradient-based optimization. We describe the design and implementation of relentless in the context of relative entropy minimization, and we demonstrate its abilities to design pairwise interactions between particles that form targeted structures. relentless aims to streamline the development of computational materials design methodologies and promote the transparency and reproducibility of complex workflows integrating molecular dynamics simulations.
Structural transitions of calcium carbonate by molecular dynamics simulation
Authors: Sidler Elizaveta , Cabriolu Raffaela
Published: December 2024

Calcium carbonate (CaCO3) plays a crucial role in the global carbon cycle, and its phase diagram is of significant scientific interest. We used molecular dynamics to investigate selected structural phase transitions of calcium carbonate. Using the Raiteri potential, we explored the structural transitions occurring at the constant pressure of 1 bar, with temperatures ranging from 300 to 2500 K, and at the constant temperature of 1600 K, with pressures ranging from 0 to 13 GPa. With increasing temperature, the transitions between calcite, CaCO3-IV, and CaCO3-V were characterized. In the calcite structure, the carbonate ions are ordered in a planar triangular arrangement, alternating with layers of calcium ions. As the temperature increases, the transition from calcite to CaCO3-IV occurs, leading to partial disordering of the carbonate ions. At higher temperatures, CaCO3-IV transforms into CaCO3-V. Through free energy analysis, we classified the latter transition as a continuous phase transition. At a temperature of 2000 K, a “disordered CaCO3” structure appears, characterized by low order within the calcium and carbonate sublattices and the free rotation of the carbonate ions. With increasing pressure, two calcium carbonate transformations were observed. At P = 2 GPa, the CaCO3-V phase undergoes a phase transition into CaCO3-IV, demonstrating that the model can describe the transition between these two phases as pressure- and temperature-driven. At P = 4.25 GPa, CaCO3-IV undergoes a phase transition into the CaCO3-Vb phase. This transition is classified as first-order based on free energy calculations.
Effects of total temperature and equivalence ratio on n-decane/air two-phase rotating detonation wave
Authors: Zhang Wei , Zhao Ningbo , Shao Xiaofeng , Meng Qingyang , Jin Shan , Zheng Hongtao
Published: December 2024

The Eulerian–Lagrangian method is used to conduct the numerical simulation of the non-premixed two-phase rotating detonation wave (RDW) fueled by n-decane/air. The stratified spray detonation transient phenomena, as well as the effects of total temperature (850, 900, 1000 K) and equivalence ratio (0.5, 0.7, 1.0) on the RDW dynamics and propagation characteristics are discussed in detail. The results indicate that the velocity difference caused by separate injection of fuel and air generates the low-temperature zone behind the oblique shock wave, which hinders the direct contact between the droplets and the detonation products. Droplets in the refilled zone are broken by the shear effect and evaporate in high total temperature air, forming the stratified distribution structure of droplets and vapor. In addition, the coupling–decoupling–recoupling dynamic mechanism is observed between the leading shock front and the heat release zone, which leads to the local decoupling of RDW during the propagation. Moreover, the spatial variation of high-pressure zones at the leading shock front leads to multiple leading shock fronts and transverse pressure waves. It is revealed that the increase in total temperature broadens the lower boundary of equivalence ratio to obtain two-phase RDW. RDW velocity and velocity deficit are insensitive to the total temperature in the considered parameter range. However, the increase in the total equivalence ratio not only improves the mean velocity significantly but also enlarges the velocity deficit. With the increasing total temperature and equivalence ratio, the stability of pressure becomes worse. Furthermore, the stability of velocity declines with the increasing equivalence ratio at the total temperature of 1000 K.
Experimental study of flow-induced vibration in a two degrees-of-freedom flexibly mounted triangular prism in crossflow
Authors: Chowdhury Naumi Noshin , Seyed-Aghazadeh Banafsheh
Published: December 2024

This study experimentally investigates the flow-induced vibration (FIV) of a flexibly mounted triangular prism with two degrees of freedom (DoF), capable of oscillating in its first two vibrational modes in the crossflow direction. The experiments were conducted by varying the angle of attack (α) in the range of 0°–60° and eigenfrequency ratio (R), which is the ratio between the second and first eigenfrequency, from R = 1.5 to 3. For α = 0° and 15°, no significant oscillations were observed. At α=30°, both vortex-induced vibration (VIV) and galloping-type response were detected. For higher angles of attack, α = 45° and 60°, a pure galloping type response was identified. Hydrogen bubble flow visualization was employed to analyze the vortex-dominated wake and to discern the nature of the FIV response—whether it was VIV or galloping. Although the prism was free to oscillate in both its first and second modes, only the first mode contributed to the FIV response at α = 45° and 60°, where galloping was dominant. The FIV response remained primarily influenced by the first mode, except when mode two was externally excited, resulting in pronounced hard mode-two galloping behavior. Because mode one predominantly drives the system's overall FIV response, variations in the eigenfrequency ratio had minimal impact on the system's overall FIV behavior.
Bubble dynamics in liquid metals under external horizontal magnetic field
Authors: Corrado Marino
Published: December 2024

In this study, computational fluid dynamics simulation was used to derive full understanding of a bubble rising in liquid metals with the presence of an external horizontal magnetic field. The major aim of the study was to develop new correlations for bubble velocity and stability in liquid metals. In-house code PSI-BOIL (Parallel SImulator of BOILing phenomena, developed by Paul Scherrer Institute, Switzerland) has been used for the simulations. Single bubble rising in quiescent liquid is simulated for three different sets of materials (nitrogen+mercury, argon+GalnSn, and argon+steel). The influence of external horizontal magnetic field on bubble dynamics is analyzed, and vertical magnetic field is not considered in this study. Overall, results show that horizontal magnetic field reduces bubble rising velocity, straightens the bubble trajectory, and enhances bubble interface stability.
Five-stage dynamics of discontinuous oil phase migration in the constricted microchannel: A quantitative analysis of the Jamin effect
Authors: Long Long , Cheng Shitong , Chen Xu , Gu Xiaoyu , Dong Mingzhe
Published: December 2024

The transport of discontinuous oil phases in constricted microchannels is a significant issue within the domains of the petroleum industry, bioengineering, and other industrial processes. During the transport, there is a pressure obstructing the drop flow through the narrow throat, which is named the Jamin effect. In this study, computational fluid dynamics technique is employed to observe and analyze the pressure drop of the discontinuous oil phase during its passage through a constricted microchannel and provides a quantitative analysis for the Jamin effect. The results show that the discontinuous oil phase undergoes five stages during its migration in the constricted microchannel, namely, the preparatory stage, the development stage of the forward meniscus, the quasi-stable stage, the regression stage of the rear meniscus, and the stable stage. Moreover, the composition of resistance in the Jamin effect is not solely due to capillary pressure, as traditional scholars believe. The analysis indicates that the equivalent viscosity of the discontinuous oil phase remains consistent during both the preparatory stage and the stable stage, demonstrating that the magnitude of the equivalent viscosity is unaffected by the profile of the oil phase. Additionally, the effects of oil phase saturation, viscosity, and capillary number on the Jamin effect also have been discussed.
Conformation and topology of cyclical star polymers
Authors: Breoni Davide , Locatelli Emanuele , Tubiana Luca
Published: December 2024

We study the conformation and topological properties of cyclical star polymers with f ring arms, each made of n beads. We find that the conformational properties of unlinked cyclical star polymers are compatible with those of linear star polymers with 2f arms made of n/2 beads each. This compatibility vanishes when the topology of the star, measured as the degree of linking between arms, changes. In fact, when links are allowed, we notice that the gyration radius decreases as a function of the absolute linking number |Lk| of the arms, regardless of the protocol that is employed to introduce said links. Furthermore, the internal structure of the macromolecules, as highlighted by the radial density function, changes qualitatively for large values of |Lk|.
Exploiting the positive effect of REFe2 (RE=rare earth) phase on coercivity in Nd-Ce-Fe-B sintered magnets
Authors: Lai Rongshun , Ma Qiang , Liang Qichao , Li Zhibin , Xu Haibo , Jiang Bo , Zhou Xianglong , Wang Xin , Shen Baogen
Published: December 2024

The REFe2 phase is inherent in high Ce content Nd-Ce-Fe-B magnets, and how to harness its existence and exert its beneficial effects on magnetic properties is an essential topic in the development of these magnets. In this work, we reveal the positive impact of the REFe2 phase on coercivity enhancement by designing the RE-rich B-lean composition in the Nd-Ce-Fe-B sintered magnet with 30 wt. % Ce replacing Nd. The coercivity in the as-sintered state attains 14.07 kOe and slightly increases to 14.54 kOe upon post-sinter annealing. Phase composition and microstructure analysis indicate that the Fe-storage effect of the REFe2 phase immobilizes a large amount of Fe elements in the triple junctions, resulting in the development of a continuous Fe-lean non-ferromagnetic grain boundary phase with thickness exceeding the exchange length. In addition, the magnetization and demagnetization behaviors were analyzed by the recoil loops to reveal the coercivity mechanisms. This work demonstrates that, in addition to improving wettability, the Fe-storage effect of the REFe2 phase positively influences coercivity.
Resilient Semi-Supervised Meta-Learning Network based on wavelet transform and K-means optimization for fluid classification
Authors: Li Hengxiao , Pang Shanchen , Sun Youzhuang
Published: December 2024

In the field of geological exploration, accurately distinguishing between different types of fluids is crucial for the development of oil, gas, and mineral resources. Due to the scarcity of labeled samples, traditional supervised learning methods face significant limitations when processing well log data. To address this issue, this paper presents a novel fluid classification method known as the Resilient Semi-Supervised Meta-Learning Network (RSSMLN) based on wavelet transform and K-means optimization, which combines the advantages of few-shot learning and semi-supervised learning, aiming to optimize fluid recognition in well log data. Initially, this study employs a small set of labeled samples to train the initial model and utilizes pseudo-label generation and K-means clustering to optimize prototypes, thereby enhancing the model's accuracy and generalization ability. Subsequently, during the feature extraction process, wavelet transform preprocessing techniques are introduced to enhance the time-frequency feature representation of well log data through multi-scale decomposition. This process effectively captures high-frequency and low-frequency features, providing structured information for subsequent convolution operations. By employing a dual-channel heterogeneous convolutional kernel feature extractor, RSSMLN can effectively capture subtle features of the fluids and significantly improve classification accuracy. Experimental results indicate that compared to various standard deep learning models, RSSMLN achieves superior performance in fluid identification tasks. This research provides a reliable solution for few-shot fluid recognition in oilfield applications and offers scientific support for resource exploration and evaluation.
A simulation platform for slender, semiflexible, and inextensible fibers with Brownian hydrodynamics and steric repulsion
Authors: Maxian Ondrej , Donev Aleksandar
Published: December 2024

The last few years have witnessed an explosion of new numerical methods for filament hydrodynamics. Aside from their ubiquity in biology, physics, and engineering, filaments present unique challenges from an applied-mathematical point of view. Their slenderness, inextensibility, semiflexibility, and meso-scale nature all require numerical methods that can handle multiple lengthscales in the presence of constraints. Accounting for Brownian motion while keeping the dynamics in detailed balance and on the constraint is difficult, as is including a background solvent, which couples the dynamics of multiple filaments together in a suspension. In this paper, we present a simulation platform for deterministic and Brownian inextensible filament dynamics, which includes nonlocal fluid dynamics and steric repulsion. For nonlocal hydrodynamics, we define the mobility on a single filament using line integrals of Rotne–Prager–Yamakawa regularized singularities and numerically preserve the symmetric positive definite property by using a thicker regularization width for the nonlocal integrals than for the self-term. For steric repulsion, we introduce a soft local repulsive potential defined as a double integral over two filaments, then present a scheme to identify and evaluate the nonzero components of the integrand. Using a temporal integrator developed in previous work, we demonstrate that Langevin dynamics sample from the equilibrium distribution of free filament shapes and that the modeling error in using the thicker regularization is small. We conclude with two examples, sedimenting filaments and cross-linked fiber networks, in which nonlocal hydrodynamics does and does not generate long-range flow fields, respectively. In the latter case, we show that the effect of hydrodynamics can be accounted for through steric repulsion.
Wettability and physical modification of coal under vacuum saturation invasion of SiO2 nanofluids
Authors: Ni Guanhua , Gong Li , Li Zhao , Li Moyu , Shang Yuanmeng , Zhang Xiangkun
Published: December 2024

Coal seam water injection technology could improve the water content of coal seam, which is an effective technical measure to reduce dust generation in the mining process. Water-based silica nanofluids are a green wetting agent for coal seam water injection. To understand the wetting mode of nanofluids in coal, it is necessary to explore the physico-chemical properties of nanofluid-modified coals. First, a new idea of saturation and intrusion of nanofluid into coal was proposed by using vacuum pressurized saturation device. Then, the physical and chemical properties of the modified coal were studied by Fourier transform infrared spectrometer, low-temperature liquid nitrogen adsorption experiments, and uniaxial compression mechanics experiments. The results showed that the content of oxygen-containing functional groups in the modified coal increased, which was positively correlated with the concentration of nanofluids. The pore structure of the modified coal sample changed from complex to simple, and the nanoparticles blocked the micropores to make the coal surface smooth. The saturation invasion of SiO2 nanofluids changed the mechanical properties of coal samples, and the compressive resistance of coal was weakened, and the minimum strength of the coal invaded by 1.5 wt. % SiO2 nanofluid saturation was 13.68 MPa. The saturation intrusion of SiO2 nanofluids has a negative effect on the surface adsorption of coal samples and the blockage of microporous structures, and makes the coal seam easier to be wetted, which contributes to the application and development of nanofluids in the field of coal seam water injection.
Experimental investigation of turbulent energy spectra affected by submerged vegetation in shallow open channel flows
Authors: Mao Ran-Ran , Lu Yesheng , Cheng Nian-Sheng
Published: December 2024

In the presence of vegetation in open channel flows, various physical processes, such as sediment transport, may be dominated by large-scale eddies, of which mechanisms are not well understood at present. In this study, we aimed to explore vegetation-affected turbulence from the perspective of energy spectral analysis. First, we conducted a series of laboratory experiments of open channel flows with submerged vegetation by varying the flow rate, water depth, and vegetation density. With flow velocities measured using the particle image velocimetry (PIV) technique, energy spectral analyses were then performed over several representative locations in the flow field. The results show that the Kelvin–Helmholtz (KH) vortices dominate the flow in the surface layer, while the shedding wake controls the flow in the vegetation layer, particularly downstream of individual vegetation stems. The normalized frequency of the KH vortices increases for flows with dense vegetation, of which the peak value, when normalized as the Strouhal number, has an average of 0.21. Furthermore, by applying Taylor's frozen turbulent hypothesis, it is shown that both the scale of the KH vortices and the penetration depth reduce when the vegetation becomes dense. Within the vegetation layer, the minimum of the peak streamwise wavelength is observed to be related to the shedding wake, while its maximum scales with the size of the penetrating KH vortices.
Detonation flows of explosives containing compressible inert particles
Authors: Qin Jian , Chen Qian , Zhou Rui , Jia Zupeng , Xu Aiguo
Published: December 2024

The present study employs a combination of numerical and analytical techniques to examine the detonation flows of explosives containing compressible inert particles. A two-phase numerical model incorporating the compressibility of the particles is developed, and the two-phase detonation process is simulated under the Lagrangian framework, where the explosive and the particles are treated as a fluid and discrete spheres, respectively. For small velocity difference between phases, a perturbation method is utilized for the analysis of the dynamics of the detonation front, the detonation product, and the particles. The effects of the particles' compressibility and material density are examined in detail. The results show that the material density of the particles exerts a linear influence on the detonation flow of the explosive, while the effects of the particle compressibility are much more complex. An increase in the particle's material density or compressibility can reduce the velocities of both the detonation front and the flowing-stagnant boundary. The jump of the particle volume fraction across the detonation front relies on the particle compressibility. For more compressible particles, the particle volume fraction exhibits a non-monotonic behavior in the flowing region. A concise scaling law is also obtained for the velocity difference between phases. The present research provides a quantitative prediction to the effects of compressible particles on the detonation flows of explosives.
Comprehensive study of Schottky-gated p-channel GaN field-effect transistors
Authors: Chen Jiahao , Zhang Tao , Su Huake , Xu Shengrui , Ren Zeyang , Du Yu , Li Xiangdong , Hao Yue , Zhang Jincheng
Published: December 2024

In this work, a comprehensive study of Schottky-gated p-channel GaN field-effect transistors (GaN PFETs) with an energy-band modulated AlGaN barrier layer, a variable gate structure, and various densities of holes in the p-GaN layer is demonstrated to optimize electrical performance. The design rules for high-performance Schottky-gated GaN PFETs not only offer diverse pathways to achieve enhancement-mode operation but also improve output current density. Based on the design rules, a high-performance enhancement-mode GaN PFET with a high ION/IOFF ratio of 3 × 106, a low SS of 130 mV/dec, and a negative VTH of −1.09 V is fabricated, which is conducive to promoting the development of the low-power GaN complementary metal–oxide–semiconductor driving circuits.
The association between antimicrobial resistance mutations and treatment outcomes for Mycoplasma genitalium infections from 2018 to 2022: a cross-sectional study from Auckland, New Zealand
Authors: Fox-Lewis Shivani , Forster Rose , Basu Indira , Blakiston Matthew , McAuliffe Gary
Published: December 2024

Background New Zealand has among the highest rates of antimicrobial resistance in Mycoplasma genitalium in the world. The aim of this study was to correlate treatment outcomes with 23S rRNA and parC mutations associated with macrolide and fluroquinolone resistance, respectively, in a cohort of sexual health clinic patients. Methods Laboratory and clinical data were collected for patients with M. genitalium infections attending Auckland Sexual Health Service between 1 January 2018 and 31 December 2022, who had a test-of-cure performed within 21–90 days of a treatment episode. Treatment outcomes were correlated with the presence or absence of resistance mutations and treatment regimen utilised. Results A total of 95 infections from 93 patients met the study inclusion criteria. Eighty of 93 (86%) infections with available data were macrolide resistant, with 20 of 74 (27%) having both macrolide resistance and parC mutations. Sixteen of 20 (80%) of parC mutations were G248T (S83I), three of 20 (15%) G259T (D87Y) and one of 20 (5%) A247C (S83R). All macrolide-susceptible infections treated with doxycycline and azithromycin were cured (12/12), as were all macrolide-resistant infections without parC mutations treated with doxycycline and moxifloxacin (37/37). Cure rates for macrolide-resistant infections with parC mutations were lower, with variable and often multiple treatment courses; eight of 16 (50%) were cured using one course of sequential doxycycline and moxifloxacin, seven of nine (78%) with one course of minocycline, zero of two (0%) with pristinamycin and one of one (100%) with doxycycline and sitafloxacin. Conclusions Our findings highlight the differing treatment outcomes for infections with and without parC mutations, offering opportunities to refine management of M. genitalium infections.
An efficient design methodology for a tri-state multiplier circuit in carbon nanotube technology
Authors: Haq Shams Ul , Orouji Maedeh , Khurshid Tabassum , Abbasian Erfan
Published: December 2024

This study delves into the computational aspects of ternary logic and the use of carbon nanotube field-effect transistors (CNTFETs) to develop an energy-efficient and robust ternary multiplier (TMUL). Leveraging the exceptional qualities of CNTFETs, such as balanced electron and hole mobility and easy modulation of threshold voltage, the research aims to achieve the desired designs. An innovative design method is employed, recommending a reduced count of logic gates for achieving necessary logic levels. These gates are then utilized to manage the activation and deactivation of the primary transistors within the TMUL cell to convey the intended logics to the outputs. Moreover, the suggested design is focused on a single-V

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, enhancing compatibility with the goals of a multi-valued logic platform. The proposed circuit is validated using Synopsis HSPICE simulator and Stanford’s standard 32-nm CNTFET model file. Comparative analysis with existing TMUL designs demonstrates a 25.43% decrease in average power consumption, a 42.24% reduction in power-delay product (PDP), and a 24.69% decrease in energy-delay product (EDP). The design undergoes thorough simulations under various conditions including load variations and process, voltage, and temperature (PVT) fluctuations to confirm its reliability and robustness.
Design, DFT, experimental, and NLO studies of a new hybrid containing 1,3,4-oxadiazole and indole moieties
Authors: Hassan Sabreen Mahdi , Jassem Ahmed Majeed , Hassan Qusay M A , Sultan H A , Muala Dhumad Adil , Emshary C A
Published: December 2024

In this article, design and nonlinear optical (NLO) response studies of a new synthesized hybrid molecule (HM 6) containing 1, 3, 4-oxadiazole and indole moieties are introduced. The spatial structure of the target hybrid is analytically determined using 1HNMR, 13CNMR, FT-IR, UV–vis., and Mass spectra. Efficiency of the fully optimized geometry of the synthesized HM (6) is elucidated via energy gap (EHOMO-ELUMO), potential ionization, and electron affinity. The small energy gap leads to efficient NLO response. The cooperation of 1, 3, 4-oxadiazol moiety as a good acceptor and indole as a good donor in the HM (6) enhances long π-conjugation system, led to large hyperpolarizability (β = 2.79 × 10−28 esu). Density functional theory and TD-DFT-assisted calculations proved high potential intramolecular charge transfer and effective β value verify NLO activities. The NLO activities of the HM (6) are examined under the excitation with 473 nm, single transverse, low power laser beam via diffraction patterns (DPs), and Z-scan techniques. As high as 5.49 × 10−11 m2/W of nonlinear refractive index due to the DPs technique has been obtained. Both the nonlinear refractive index and nonlinear absorption coefficient are estimated via the standard Z-scan methods. The all-optical switching, both static and dynamic, prove to occur in the HM (6) using two visible laser beams.
Biomass combined heat and power for renewable power provision in mountain environments: techno-economic assessment of cost factors and competitiveness under current and projected energy market conditions
Authors: Menin Lorenzo , Paolillo Aldo , Piazzi Stefano , Antolini Daniele , Rossi Diego , Ravazzolo Francesco , Baratieri Marco
Published: December 2024

Bioenergy is seen as a renewable energy source expected to deliver a major contribution to decarbonization of power and heat by major institutions, although its affordability in specific contexts has not been assessed in detail by the available literature. In this study, we develop a techno-economic model of a small-scale decentralized biomass gasification-combined heat and power plant based on real operating data and costs. The results obtained indicate that in the Italian mountain context, the proposed solution would deliver very limited competitiveness compared to natural gas fired generation or grid electricity in Europe, with a levelized cost of energy of 359 €/MWh for a 225-kW plant. Sensitivity analyses show that the average yearly operating hours is by far the greatest cost factor affecting plant economics, while a forecast of natural gas prices allowed estimating the subsidization requirements of the system over its full project life, indicating total subsidy of €149.4M even under a 120 €/t carbon emission allowance cost placed on natural gas. The methodology and results proposed represent an important further step in the direction of sound regional bioenergy planning and support policy development.
Development of a Power Conversion System for a Wave Energy Converter connected to the Electrical Network
Authors: Barone Piofrancesco , Vizza Pasquale , Petrocca Antonio , Pinnarelli Anna , Castiglione Teresa , Bova Sergio
Published: December 2024

Global efforts are focused on promoting a sustainable energy supply by increasing the use of renewable energies and decreasing reliance on conventional sources. Among renewable sources, Wave energy is a promising one, but it is still widely untapped worldwide. In the current energy context, it is crucial to synchronize the characteristics of renewable sources with the needs of the existing electrical network which is undergoing a deep change towards the smart grid paradigm. Power electronic converters, as interface devices, play a fundamental role in facilitating the transfer of renewable energy to the electrical network. For this reason, this study focuses on the design and optimization of an electrical power conversion system for a wave energy converter (WEC) coupled with a hydraulic power take-off. This electrical power conversion system allows the WEC to connect to the electrical network and deliver a smooth output electrical power. Indeed, thanks to a particular control system, the conversion from mechanical power to electrical power is achieved with losses of less than 5% in regular sea state conditions