bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Synthesis of N-(Difluoropropenyl)amides/Amines from Fluorinated Olefins under Base Promotion
Authors: Li Yang , Li Xin-Yue , Shi Yi-Ran , Li Zhi-Bo , Li Hong , Zhu Wen-Qing , Fan Qiang-Wei
Published: April 2024

N-(Difluoropropenyl)amides/amines are an important class of fluorinated compounds. Here, we report an efficient method for synthesizing these compounds without the use of transition metals. Under simple base-promoted conditions, 3-bromo-3,3-difluoroprop-1-ene reacts with N-methylanilines or N-arylacrylamides, with the elimination of one molecule of HBr, to give the target compound. Another efficient method for synthesizing difluoroalkenes is the reaction of 2-bromo-3,3,3-trifluoroprop-1-ene with indole or its analogues.
The Clinical Translation of α-humulene – A Scoping Review
Authors: Dalavaye Nishaanth , Nicholas Martha , Pillai Manaswini , Erridge Simon , Sodergren Mikael H.
Published: April 2024

α-humulene, a sesquiterpene found in essential oils of various plant species, has garnered interest due to its potential therapeutic applications. This scoping review aims to consolidate α-humuleneʼs evidence base, informing clinical translation, and guiding future research directions. A scoping review was conducted of EMBASE, MEDLINE, and PubMed databases up to 14th July 2023. All studies describing original research on α-humulene extraction, as well as pre-clinical and clinical research, were included for review. Three hundred and forty articles were analysed. α-humulene yields ranged from negligible to 60.90% across plant species. In vitro experiments demonstrated cytotoxicity against adenocarcinomas (such as colorectal, pulmonary, breast, prostatic, lung, and ovarian), with varying responses in other cell models. Mechanistic insights revealed its involvement in mitochondrial dysfunction, diminished intracellular glutathione levels, and the induction of oxidative stress. In rodent studies, oral administration of α-humulene at 50 mg/kg reduced inflammation markers in paw oedema and ovalbumin-induced airway inflammation. Intraperitoneal administration of α-humulene (50 – 200 mg/kg) exhibited cannabimimetic properties through cannabinoid 1 and adenosine A2a receptors. α-humulene also exhibited a multitude of properties with potential scope for therapeutic utilisation. However, there is a paucity of studies that have successfully translated this research into clinical populations with the associated disease. Potential barriers to clinical translation were identified, including yield variability, limited isolation studies, and challenges associated with terpene bioavailability. Consequently, rigorous pharmacokinetic studies and further mechanistic investigations are warranted to effectively uncover the potential of α-humulene.
Transition-Metal-Catalyzed Direct Arylation of Ammonia
Authors: Song Geyang , Dong Jianyang , Xue Dong , Song Jiameng , Li Gang
Published: April 2024

In the past few decades, transition-metal-catalyzed direct amination of aryl halides with ammonia has attracted significant attention from chemists because of its broad substrate scope, good functional group compatibility, and high reaction selectivity. Herein, recent examples of transition-metal-catalyzed syntheses of aniline derivatives starting from aryl halides are reviewed.

1 Introduction

2 Heat-Driven Transition-Metal-Catalyzed Amination of Aryl Electrophiles

2.1 Palladium-Catalyzed Amination

2.2 Copper-Catalyzed Amination

2.3 Nickel-Catalyzed Amination

3 Light-Driven Transition-Metal-Catalyzed Amination of Aryl Electrophiles

4 Conclusion and Outlook
A Comparison of Perioperative Complications and Outcomes in Patients Undergoing Cerebral Aneurysm Clipping Performed Ultra-Early (≤ 24 hours) versus Late (> 24 hours): A 7-Year Retrospective Study of 302 Patients
Authors: Muangman Saipin , Raksakietisak Manee , Vacharaksa Kamheang , Manomatangkul Kattiya , Chankaew Ekawut , Kotchasit Chayasorn , Deepinta Penpuk , Phoowanakulchai Sirima
Published: April 2024

Objectives The intracerebral aneurysm with subarachnoid hemorrhage (SAH) has a high morbidity and mortality rate. This study aimed to compare the incidences of perioperative complications in ultra-early surgery (within 24 hours) with those in late surgery (> 24 hours).

Methods Retrospective data were reviewed for 302 patients who underwent craniotomies with aneurysm clipping between January 2014 and December 2020. Perioperative data were obtained from the medical records and reviewed by the investigators. The complications were compared between ultra-early and late operations. We were interested in major complications such as delayed ischemic neurologic deficit (DIND), intraoperative aneurysm rupture (IAR), and anesthesia-related complications. The short-term (in hospital) and long-term (1 year) outcomes in patients with or without DIND and IAR were compared. The collected data was statistically analyzed.

Results Three hundred and two patients were analyzed, and 264 patients had completed follow-up. The ultra-early cases (150 patients) had a higher American Society of Anesthesiologists physical status, a lower Glasgow Coma Scale, and higher Hunt and Hess scales. The surgeons operated on more cases of the anterior cerebral artery as ultra-early operations. The incidence rates of DIND, IAR, severe hemodynamic instability, and cardiac arrest were 5.6, 8.3, 6.3, and 0.3%, respectively, which were not different between groups. However, the reintubation rate was higher in the ultra-early surgery cases (0 vs. 3.3%, p = 0.023). The DIND and IAR patients had poorer short-term (in hospital) outcomes.

Conclusions There were no differences in major complications between ultra-early and late craniotomy with aneurysm clipping. However, the reintubation rate was strikingly higher in the ultra-early group. Patients with major complications had early, unfavorable outcomes.
Prenatal Diagnosis of a Case of Asyndromic Tessier Class-7 Bilateral Complete Transverse Facial Cleft: Case Report with Review of Literature
Authors: Vikraman Seneesh Kumar , Yandamuri Shasmita , Desai Jay
Published: April 2024

Transverse or lateral facial clefts are atypical and rare forms of facial clefts identified as Tessier type 7 in the classification system for orofacial clefts. They have an overall incidence of 1 in 60,000 to 300,000 live births. We report a case diagnosed at 22 weeks of gestation. The two-dimensional (2D) ultrasound examination revealed a single live fetus with a persistently open mouth, failure of visualization of lateral commissures, and mild retrognathia. The three-dimensional (3D) surface rendering of the fetal face demonstrated a bilateral horizontal facial cleft that extended from the lateral commissures to the ears. No additional anomalies were identified. Fetal karyotype and whole exome sequencing reports did not reveal any genomic imbalances. The case highlights the importance of 2D oblique and 3D imaging of the fetal face when subtle findings are detected in routine 2D views. A review of the literature is provided to enhance the understanding of the entity.
Congenital Hallux Varus: A Rare Prenatal Detection and Postnatal Management
Authors: Aloorkar Prajakta , Vemavarapu Gayathri , T. Venkatram , R. Shantisree
Published: April 2024

Congenital hallux varus (CHV) is an uncommon anomaly of the forefoot where the big toe is positioned medially at the metatarsophalangeal joint, accompanied by a significant gap between the first and second toes. CHV is associated with difficulty in wearing clothes and footwear. CHV can cause pain that hampers the quality of life and can often be aesthetically displeasing.

Although prenatal presentation is rare, CHV can be detected by antenatal ultrasound with appropriate foot examination and a high index of suspicion. Early detection and management are recommended for optimizing antenatal and postnatal management as they may reduce the chance of permanent deformity.

We are herewith reporting a prenatally detected case of a CHV with polysyndactyly and its management. This is one of the few prenatally reported cases of isolated unilateral foot abnormalities.
Humeral Condylar Fractures in French Bulldogs: Prevalence of Contralateral Intracondylar Fissure, Treatment, and Outcome
Authors: Lopez de la Oliva Paula , Arnott Luke , Roses Leonor , Marshall William , Arnott Davinia
Published: April 2024

Objective The aim of this study was to report (1) the prevalence of contralateral humeral intracondylar GAP/HIF (HIF) in French Bulldogs with humeral condylar fractures (HCF) and (2) treatment and short- and long-term outcome in French Bulldogs with HCF.

Materials and Methods Medical records of French Bulldogs treated surgically for HCF between January 2011 and November 2022 were reviewed. Perioperative imaging, surgical technique, complications, and long-term outcome were assessed.

Results Eighty-nine dogs with HCF were included and 36/89 were diagnosed with HIF. Surgical repair was performed in all HCF and a prophylactic transcondylar screw was placed in 20/36 HIF. For prophylactic transcondylar screw placement, two dogs required immediate revision surgery. Complications occurred in 12/89 HCF, and there were major complications in 6/89 HCF. Long-term outcome evaluated by owner questionnaire (n = 27) was rated as being excellent in 18/27 dogs, good in 8/27 dogs, and fair in 1/27 dogs.

Clinical Significance Forty percent of French Bulldogs with HCF had a contralateral HIF. HIF as a cause of HCF should be considered in the French Bulldog, and a computed tomography (CT) scan of both elbows may be advisable prior to HCF repair. The complication rate of HCF surgery in the French Bulldog is significant.
Prognostic Implications of Early Prediction in Posttraumatic Epilepsy
Authors: Chen Yilun , Cappucci Stefanie P. , Kim Jennifer A.
Published: April 2024

Posttraumatic epilepsy (PTE) is a complication of traumatic brain injury that can increase morbidity, but predicting which patients may develop PTE remains a challenge. Much work has been done to identify a variety of risk factors and biomarkers, or a combination thereof, for patients at highest risk of PTE. However, several issues have hampered progress toward fully adapted PTE models. Such issues include the need for models that are well-validated, cost-effective, and account for competing outcomes like death. Additionally, while an accurate PTE prediction model can provide quantitative prognostic information, how such information is communicated to inform shared decision-making and treatment strategies requires consideration of an individual patient's clinical trajectory and unique values, especially given the current absence of direct anti-epileptogenic treatments. Future work exploring approaches integrating individualized communication of prediction model results are needed.
A Single Standard Polyvinyl Chloride 3D Skull Model to Create the Polymethyl Methacrylate Cranioplasty Flap: A Novel and Low-Cost Technique
Authors: Prajapati Hanuman Prasad , Singh Deepak Kumar
Published: April 2024

Background Although, cranioplasty is a commonly performed neurosurgical procedure worldwide, the cost of available cranioplasty implants is a major issue in a low-income country like India. The aims of this study were to introduce a novel and low-cost technique using a single standard three-dimensional (3D) skull model to guide the polymethyl methacrylate (PMMA) cranioplasty flap production and to evaluate the functional and cosmetic outcomes.

Methods We retrospectively evaluated 47 cases of PMMA cranioplasty in the period from February 2019 to June 2022. A single standard 3D skull model was used to make the PMMA cranioplasty flaps. The overall cost of this PMMA implant was compared with that of other available cranioplasty implants. The functional and cosmetic outcomes were evaluated postoperatively.

Results The mean age of our patients was 37.17 ± 13.83 years and the age range was 17 to 63 years. The primary cause of surgery was trauma in the majority of cases (n = 31, 65.96%). The mean operative time was 78.55 ± 19.82 minutes. The cosmetic results were very satisfying in 46 of 47 (97.87%) patients and moderately satisfying in 1 (2.12%) patient. Overall, there were three (6.38%) complications.

Conclusion Our technique provides excellent functional and cosmetic outcomes. The overall surgical cost of these PMMA implants was lower than that of the other available cranioplasty implants. This technique is currently the most cost-effective option for cranioplasty.
Feasibility and Safety of Bridging Antiplatelet Therapy with Cangrelor in Neuro-Oncology: A Preliminary Experience
Authors: Bertolini Giacomo , Belli Laura , Mazza Stefania , Ugolotti Pietro Tito , Tadonio Iacopo , Ceccarelli Patrizia , Rossi Sandra , Ippolito Salvatore
Published: April 2024

Antiplatelet therapy is mandatory for prevention of thrombotic events in patients with a recent history of acute coronary syndromes and/or percutaneous coronary interventions. However, if an urgent surgery is required during antiplatelet therapy, a compromise between the ischemic/thrombotic and hemorrhagic risk has to be reached. Different bridging schemes are reported in the literature, but there is no clear consensus on the optimal treatment strategy in terms of efficacy and safety. Although some indications about the perioperative management of antiplatelet therapy regarding specific surgical specializations are available, balancing the thrombotic and hemorrhagic risk on an individual basis, no evidence referring to neurosurgical or neuro-oncologic procedures is reported. Herein, we present our preliminary experience in the perioperative management of a patient who underwent a neurosurgical procedure for the resection of a primary malignant brain tumor using an intravenous P2Y12 inhibitor (cangrelor) as bridging therapy after a recent acute myocardial infarction treated with primary percutaneous coronary intervention and stenting. The oral P2Y12 inhibitor (clopidogrel) was withdrawn 5 days prior to the surgical procedure and continuous infusion of cangrelor was started 3 days before the surgery at a dose of 0.75 μg/kg/min. Cangrelor was discontinued 2 hours before surgery and resumed 72 hours after tumor resection for further 60 hours. Neither cangrelor-related bleeding nor cardiac ischemic events were observed in the perioperative period and the following 90 days, supporting data regarding the feasibility and safety of this bridging scheme. Further studies are needed to confirm our promising results.
Large Skull Metastasis in Follicular Thyroid Carcinoma: A Comprehensive Case Presentation and Systematic Review
Authors: Scalia Gianluca , Porzio Massimiliano , Costanzo Roberta , Giurato Eliana , Gibilisco Fabio , Iacopino Domenico Gerardo , Maugeri Rosario , Nicoletti Giovanni Federico , Umana Giuseppe Emmanuele , Alessandrello Raffaele
Published: April 2024

Background Skull metastases from follicular thyroid carcinoma (FTC) are infrequent but clinically significant, often presenting with localized pain, neurologic deficits, and cranial nerve dysfunction. Early detection and accurate diagnosis pose challenges due to their asymptomatic nature in some cases.

Methods A systematic literature review, conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, identified and analyzed 15 relevant studies focusing on large skull metastases in FTC. Data extraction and synthesis included clinical presentation, diagnostic methods, treatment strategies, and patient outcomes.

Results The systematic review encompassed 20 patients with secondary skull metastases from FTC, offering insights into the clinical diversity of this rare condition. Clinical presentations varied, with localized pain (70% of cases) and headaches being predominant symptoms. Imaging techniques, including computed tomography (CT) and magnetic resonance imaging (MRI), played a pivotal role in diagnosis. Surgical resection was considered in select cases, achieving complete or near-complete tumor removal in 30 to 50% of patients. Radiotherapy, including external beam radiation therapy (EBRT) and stereotactic radiosurgery (SRS), provided local control and symptom relief in 70 to 80% of cases. Systemic therapies, such as tyrosine kinase inhibitors (TKIs), showed promise in disease stabilization or regression (45% of patients). Prognosis remained poor, with a median overall survival of 6 to 12 months, reflecting an advanced and aggressive disease state.

Conclusion Managing secondary skull metastases from FTC requires a comprehensive approach, including surgical intervention, radiotherapy, and potential systemic therapies. The rarity of these metastases underscores the need for further research to establish standardized treatment guidelines, explore molecular profiling, and investigate immunotherapy and combination therapies, offering hope for improved outcomes in this challenging clinical scenario.
The Oral–Lung Microbiome Axis in Connective Tissue Disease-Related Interstitial Lung Disease
Authors: Bongers Kale S. , Massett Angeline , O'Dwyer David N.
Published: April 2024

Connective tissue disease-related interstitial lung disease (CTD-ILD) is a frequent and serious complication of CTD, leading to high morbidity and mortality. Unfortunately, its pathogenesis remains poorly understood; however, one intriguing contributing factor may be the microbiome of the mouth and lungs. The oral microbiome, which is a major source of the lung microbiome through recurrent microaspiration, is altered in ILD patients. Moreover, in recent years, several lines of evidence suggest that changes in the oral and lung microbiota modulate the pulmonary immune response and thus may play a role in the pathogenesis of ILDs, including CTD-ILD. Here, we review the existing data demonstrating oral and lung microbiota dysbiosis and possible contributions to the development of CTD-ILD in rheumatoid arthritis, Sjögren's syndrome, systemic sclerosis, and systemic lupus erythematosus. We identify several areas of opportunity for future investigations into the role of the oral and lung microbiota in CTD-ILD.
Generic Netupitant Plus Palonosetron and Dexamethasone for Prophylaxis of Chemotherapy-Induced Nausea and Vomiting (CINV) in Cancer Patients Receiving Highly or Moderately Emetogenic Chemotherapy: A Retrospective Study
Authors: Simhadri Soumya , Dayyala Sowmya , Musinipally Anjani Devi , Guram Lavanya , Madavi Mamatha , Kancha Ramakrishna , Puligundla Krishna Chaitanya
Published: April 2024

Chemotherapy-induced nausea and vomiting (CINV) is a challenging adverse effect that is associated with deteriorating quality of life. Inhibiting neurokinin 1 and 5-hydroxytryptamine type 3 receptors involved in the major emesis pathways has significantly prevented CINV and is recommended as standard treatment in international antiemetic guidelines. This retrospective study was conducted to explore the efficacy of formulated netupitant (NE; 300 mg) and palonosetron (PA; 0.50mg) tablets with dexamethasone in patients receiving high and moderate emetogenic chemotherapy. A single dose of NE, PA, and dexamethasone was given 1 hour prior to the chemotherapy for 4 days. The key end-points were to assess complete response (CR), complete protection (CP), and complete control (CC) with no emesis, no nausea, and no use of rescue medication during acute (0–24 hours) and delayed phase (24–120 hours) of CINV. This study conducted on 212 patients showed overall rates of CR, CP, and CC as 97.5, 91.1, and 92.19%, respectively, in the acute phase and 95.09, 88.06, and 87.74% in a delayed phase. These patients underwent 1,387 cycles of chemotherapy involving both high emetogenic chemotherapy and moderate emetogenic chemotherapy regimens. A decrease in the rate of CR, CP, and CC from 93.47, 76.20, and 73.90% (acute phase) to 86.95, 69.67, and 67.37% (delayed phase) with highly emetogenic chemotherapy was observed, while the combination treatment achieved 100 CR, CP, and CC in both the acute and delayed phase with the moderately emetogenic chemotherapy regimen. Our study demonstrated the promising efficacy of the triple treatment with formulated NE and PA tablets in combination with dexamethasone in preventing and managing CINV in real-world settings.
The Usefulness of YouTube Videos Related to Endoscopic Sinus Surgery for Surgical Residents
Authors: Shapiro Justin , Levin Marc , Sunba Saud , Steinberg Emily , Wu Vince , Lee John M.
Published: April 2024

Objective The use of online teaching modalities to supplement surgical learning has increased recently, demonstrating promising results. Previous studies have analyzed the value and usefulness of YouTube as an educational source to learners, including teaching surgical skills to Otolaryngology–Head and Neck Surgery (OHNS) trainees. YouTube videos on endoscopic sinus surgery (ESS) still need to be explored as ESS remains a common, yet challenging surgery that OHNS residents encounter regularly. This study aimed to objectively evaluate the usefulness of YouTube videos on ESS for surgical education.

Design YouTube was searched using the following keywords: “uncinectomy,” “maxillary antrostomy,” “anterior ethmoidectomy,” and “ethmoid bulla resection.” These represent the initial ESS steps residents learn. Each video was assessed for eligibility by two independent reviewers.

Outcome Measures The LAParoscopic surgery Video Educational Guidelines (LAP-VEGaS) and ESS-specific criteria were used to assess educational quality. Video popularity index (VPI) was used to calculate video popularity.

Results Of the 38 videos that met inclusion criteria, the average LAP-VEGaS score was 6.59 (± ) 3.23 standard deviation. Most videos were designated low quality. There was a weak positive correlation between whether a video included ESS-specific criteria and LAP-VEGaS score (r = 0.269, p = 0.102). There was a significant positive correlation between VPI and LAP-VEGaS scores (r = 0.497, p = 0.003).

Conclusions Overall, the quality of included videos was poor. OHNS residents should not rely solely or primarily on YouTube videos to learn surgical skills relevant to ESS. To maximize potential of online teaching, high-quality videos should be used to compliment other methods of teaching.
Study of pulse wave phenomena associated with blood flow model in human viscoelastic artery
Authors: Mal Tarak Nath , Soni Bharat , Nayak Ameeya Kumar
Published: April 2024

Cardiac output monitoring has proven to be a promising hemodynamic management tool especially for critically ill patients. Pulse wave analysis is a noninvasive method used to quantify cardiac output continuously with respect to time. In this article, we have proposed a novel methodology to quantify the contribution of pulse waves to further study the role of arterial wall relaxation with respect to time. The relaxation time can further help in the diagnosis of disease. The pulse wave velocity component is derived by transforming governing fluid flow equations into hyperbolic equations for laminar incompressible blood flow in an artery of viscoelastic walls. The viscoelastic behavior of the wall is analogously modeled by the modified Zener model that has the capability to measure creep, stress relaxation, and hysteresis. The derived model equations are solved numerically by the multiderivative Runge–Kutta implicit–explicit time integration method with a weighted, essentially non-oscillatory, discretization scheme. The results are well validated with clinical trial-based Riemann problems for the case of elastic walls. It is observed that the proposed modified Zener model is well suitable to identify the location of arterial stiffness where the pulse wave manifests various types of phenomena like discontinuity and reflection.
The dual nature of metal halide perovskites
Authors: Anta Juan A. , Oskam Gerko , Pistor Paul
Published: April 2024

Metal halide perovskites have brought about a disruptive shift in the field of third-generation photovoltaics. Their potential as remarkably efficient solar cell absorbers was first demonstrated in the beginning of the 2010s. However, right from their inception, persistent challenges have impeded the smooth adoption of this technology in the industry. These challenges encompass issues such as the lack of reproducibility in fabrication, limited mid- and long-term stability, and concerns over toxicity. Despite achieving record efficiencies that have outperformed even well-established technologies, such as polycrystalline silicon, these hurdles have hindered the seamless transition of this technology into industrial applications. In this Perspective, we discuss which of these challenges are rooted in the unique dual nature of metal halide perovskites, which simultaneously function as electronic and ionic semiconductors. This duality results in the intermingling of processes occurring at vastly different timescales, still complicating both their comprehensive investigation and the development of robust and dependable devices. Our discussion here undertakes a critical analysis of the field, addressing the current status of knowledge for devices based on halide perovskites in view of electronic and ionic conduction, the underlying models, and the challenges encountered when these devices are optoelectronically characterized. We place a distinct emphasis on the positive contributions that this area of research has not only made to the advancement of photovoltaics but also to the broader progress of solid-state physics and photoelectrochemistry.
A reduced-order configuration approach for the real-time calculation of three-dimensional flow behavior in a pipe network
Authors: Wang Hongjiang , Jiang Genghui , Wang Weizhe , Liu Yingzheng
Published: April 2024

The real-time computation of a three-dimensional pipe network flow is crucial for both pipe design and operational maintenance. This study devises a novel reduced-order configuration approach that combines the advantages of the acceleration characteristics of the reduced-order model and the structural applicability of the configuration model. First, a configuration model is established by categorizing sub-pipes extracted from a pipe network into sets based on the sub-pipes' type. Subsequently, reduced-order configurations are realized by a reduced-order model established for each type of configuration, enabling real-time computation of individual sub-pipes. Thus, the concatenation of sub-pipes allows the computation of an entire pipe network. A complex boundary–deep learning–reduced-order configuration model and a complex boundary–deep learning–reduced-order configuration–multi-source data–reduced-order configuration model integrated with a local multi-physical–discrete empirical interpolation method and a multi-source data fusion model are devised. These models were employed for the real-time computation and prediction of a three-dimensional velocity field for 300 snapshots composed of one to four sub-pipes extrapolated from a dataset of 294 pipe network snapshots composed of one to three sub-pipes. The maximum relative errors for snapshots from the dataset were similar to the limit precision of the proper orthogonal decomposition, with more precise accuracy than the relevant studies, indicating the excellent performance of our reduced-order configuration approach.
Unraveling thermodynamic anomalies of water: A molecular simulation approach to probe the two-state theory with atomistic and coarse-grained water models
Authors: Muthachikavil Aswin V. , Sun Gang , Peng Baoliang , Tanaka Hajime , Kontogeorgis Georgios M. , Liang Xiaodong
Published: April 2024

Thermodynamic and dynamic anomalies of water play a crucial role in supporting life on our planet. The two-state theory attributes these anomalies to a dynamic equilibrium between locally favored tetrahedral structures (LFTSs) and disordered normal liquid structures. This theory provides a straightforward, phenomenological explanation for water’s unique thermodynamic and dynamic characteristics. To validate this two-state feature, it is critical to unequivocally identify these structural motifs in a dynamically fluctuating disordered liquid. In this study, we employ a recently introduced structural parameter (θavg) that characterizes the local angular order within the first coordination shell to identify these LFTSs through molecular dynamics simulations. We employ both realistic water models with a liquid–liquid critical point (LLCP) and a coarse-grained water model without an LLCP to study water’s anomalies in low-pressure regions below 2 kbar. The two-state theory consistently describes water’s thermodynamic anomalies in these models, both with and without an LLCP. This suggests that the anomalies predominantly result from the two-state features rather than criticality, particularly within experimentally accessible temperature–pressure regions.
Classification of complex local environments in systems of particle shapes through shape symmetry-encoded data augmentation
Authors: Lee Shih-Kuang (Alex) , Tsai Sun-Ting , Glotzer Sharon C.
Published: April 2024

Detecting and analyzing the local environment is crucial for investigating the dynamical processes of crystal nucleation and shape colloidal particle self-assembly. Recent developments in machine learning provide a promising avenue for better order parameters in complex systems that are challenging to study using traditional approaches. However, the application of machine learning to self-assembly on systems of particle shapes is still underexplored. To address this gap, we propose a simple, physics-agnostic, yet powerful approach that involves training a multilayer perceptron (MLP) as a local environment classifier for systems of particle shapes, using input features such as particle distances and orientations. Our MLP classifier is trained in a supervised manner with a shape symmetry-encoded data augmentation technique without the need for any conventional roto-translations invariant symmetry functions. We evaluate the performance of our classifiers on four different scenarios involving self-assembly of cubic structures, two-dimensional and three-dimensional patchy particle shape systems, hexagonal bipyramids with varying aspect ratios, and truncated shapes with different degrees of truncation. The proposed training process and data augmentation technique are both straightforward and flexible, enabling easy application of the classifier to other processes involving particle orientations. Our work thus presents a valuable tool for investigating self-assembly processes on systems of particle shapes, with potential applications in structure identification of any particle-based or molecular system where orientations can be defined.
Global machine learning potentials for molecular crystals
Authors: Žugec Ivan , Geilhufe R. Matthias , Lončarić Ivor
Published: April 2024

Molecular crystals are difficult to model with accurate first-principles methods due to large unit cells. On the other hand, accurate modeling is required as polymorphs often differ by only 1 kJ/mol. Machine learning interatomic potentials promise to provide accuracy of the baseline first-principles methods with a cost lower by orders of magnitude. Using the existing databases of the density functional theory calculations for molecular crystals and molecules, we train global machine learning interatomic potentials, usable for any molecular crystal. We test the performance of the potentials on experimental benchmarks and show that they perform better than classical force fields and, in some cases, are comparable to the density functional theory calculations.
Numerical investigation of mixing performance in supersonic cold flow over dual-cavity in scramjet
Authors: Zhuo Ya , Qin Guoliang , Ye Ximeng
Published: April 2024

Mixing performance in the combustion chamber is important in achieving the efficiency of scramjet for its compact structure and the short residence time caused by high velocity. This study focuses on predicting the mixing performance in a viscous supersonic flow past the cavity flame holder in the scramjet, using the discontinuous spectral element method with direct numerical simulation. The arrangement and distribution of a series of cavities are calculated at various inlet velocities. By comparing the contours of Mach number and static temperature, as well as analyzing the airflow residence time with a new calculating formula and the drag based on the numerical results, it is concluded that higher inlet velocities result in faster stabilization. It also leads to longer airflow residence time when the supersonic flow passes through the dual-cavity with a tandem connection rather than the parallel one or the single-cavity structures. As for the shortened rear wall of cavities, these structures can decrease the drag quickly, but they also decrease the airflow residence time seriously, which destroys the mixing performance. In addition, these conclusions are applied to a practical case of the cavity flame holder, verifying the effectiveness of tandem dual-cavity structures in enhancing the mixing performance by increasing the airflow residence time and maintaining or reducing the drag. This study can provide valuable suggestions in further design of cavity flame holders for different flow conditions.
Dual-frequency sheath oscillations and consequences on the ion and electron transport in dielectric barrier discharges at atmospheric pressure
Authors: Robert Raphaël , Hagelaar Gerjan , Sadeghi Nader , Stafford Luc , Massines Françoise
Published: April 2024

Current–voltage characteristics, space- and time-resolved optical emission spectroscopy, and 1D fluid modeling are used to examine the effect of dual-frequency sheath oscillations on the ion and electron transport in dielectric barrier discharges sustained by a combination of low frequency (LF, 50 kHz, 650 V) and radiofrequency (RF, 5.3 MHz, 195 V) voltages, exhibiting the α-to-γ mode transition. On one hand, when polarities of the LF and RF voltages are opposite, an electric field near the LF cathode (due to LF cathode sheath) drives the secondary electrons to the plasma bulk and an opposite electric field between the sheath edge and the LF anode attracts the electrons toward the LF cathode (to maintain quasi-neutrality in the plasma bulk). At the sheath edge, electrons become trapped and ions drift toward the cathode and the anode simultaneously according to their position in the gap. On the other hand, when the RF voltage has the same polarity as the LF voltage, the total applied voltage increases and this yields to enhanced production of electrons and ions in the sheath. To maintain quasi-neutrality in the bulk, the electric field along the gap exhibits the same polarity as the one in the sheath, allowing electrons created in the sheath to be evacuated toward the LF anode. The behavior of the LF cathode is, therefore, controlled by the LF sheath, and, thus, by the LF voltage amplitude, while the behavior in the bulk and at the anode alternates on the time scale of the RF voltage.
Surprising features of the energy-mismatched nonlinear dimer
Authors: Andersen John D. , Kenkre V. M.
Published: April 2024

The quantum mechanical energy-mismatched two-state system with cubic nonlinearity in its governing equation is surprisingly rich in its dynamics and has relevance to a number of subdisciplines of physics ranging from polaron phenomena to Bose–Einstein condensation. We review some of them that have been discussed recently and describe some new results that have not, pointing out their relevance in possible experiments.
Observation of energy localization in nonlinear non-Hermitian systems
Authors: Dong Lei , Chen Dong-Yan , Huang Qing-An
Published: April 2024

Energy localization in Hermitian systems has been utilized to generate ultra-sensitivity. Here, we report the interplay between non-Hermitian parity-time (PT) symmetry breaking and the mode localization transition. In our scheme, a PT-symmetric system consists of two coupled LC (inductor–capacitor) resonators: one has a linear loss and the other has a saturated gain described by a nonlinear model. The nonlinear gain is initially set to be slightly higher than the loss, and the system is operated at the exact PT-symmetric phase close to an exceptional point. The capacitance variation applied on the loss resonator, i.e., perturbation, causes PT-symmetry to break, generating complex frequencies. As a result of nonlinear gain, the resonator will grow to reach its steady state and saturate out the gain. This stable oscillation eliminates the complex frequencies, and the mode is ultimately localized at the gain side. We have observed that the voltage amplitude of the gain resonator due to the perturbation has experienced drastic changes. The amplitude ratio before and after the perturbation is sensitive to the perturbation. Our results provide an approach to study perturbation-driven localization phenomena in a PT-symmetric system and pave the way for sensors with ultrahigh sensitivity.
Carrier tunneling and transport in coupled quantum wells: Modeling and experimental verification
Authors: Cao Fuyi , Su Zhan , Wang Cong , Chen Yuhao , Weng Guoen , Wang Chang , Hu Xiaobo , Akiyama Hidefumi , Chu Junhao , Chen Shaoqiang
Published: April 2024

We propose an approach to elucidate carrier dynamics by developing a robust rate equation model capable of explaining carrier dynamics in a dual-well system. To experimentally validate the accuracy and reliability of our model, we utilized a combination of time-resolved photoluminescence and spatially resolved cathodoluminescence measurements. The integration of these complementary techniques allowed us to thoroughly investigate the spectral characteristics in both wells, revealing distinct features attributed to carrier tunneling and transport effects and verifying the predictive ability of the model. This validation process not only confirms the model's accuracy under both coupled and uncoupled conditions but also highlights its potential applicability to quantum-well-based semiconductor lasers. Overall, our study not only advances our understanding of carrier dynamics in quantum wells but also introduces a versatile and reliable tool for designing and simulating ultrafast semiconductor lasers.
P300 intention recognition based on phase lag index (PLI)-rich-club brain functional network
Authors: Wang Zhongmin , Xiang Leihua , Zhang Rong
Published: April 2024

Brain–computer interface (BCI) technology based on P300 signals has a broad application prospect in the assessment and diagnosis of clinical diseases and game control. The paper of selecting key electrodes to realize a wearable intention recognition system has become a hotspot for scholars at home and abroad. In this paper, based on the rich-club phenomenon that exists in the process of intention generation, a phase lag index (PLI)-rich-club-based intention recognition method for P300 is proposed. The rich-club structure is a network consisting of electrodes that are highly connected with other electrodes in the process of P300 generation. To construct the rich-club network, this paper uses PLI to construct the brain functional network, calculates rich-club coefficients of the network in the range of k degrees, initially identifies rich-club nodes based on the feature of node degree, and then performs a descending order of betweenness centrality and identifies the nodes with larger betweenness centrality as the specific rich-club nodes, extracts the non-linear features and frequency domain features of Rich-club nodes, and finally uses support vector machine for classification. The experimental results show that the range of rich-club coefficients is smaller with intent compared to that without intent. Validation was performed on the BCI Competition III dataset by reducing the number of channels to 17 and 16 for subject A and subject B, with recognition quasi-departure rates of 96.93% and 94.93%, respectively, and on the BCI Competition II dataset by reducing the number of channels to 17 for subjects, with a recognition accuracy of 95.50%.
Tunable zero-field magnetoresistance responses in Si transistors: Origins and applications
Authors: Moxim Stephen J. , Harmon Nicholas J. , Myers Kenneth J. , Ashton James P. , Frantz Elias B. , Flatté Michael E. , Lenahan Patrick M. , Ryan Jason T.
Published: April 2024

The near-zero-field magnetoresistance (NZFMR) response has proven to be a useful tool for studying atomic-scale, paramagnetic defects that are relevant to the reliability of semiconductor devices. The measurement is simple to make and, in some cases, simple to interpret. In other cases, more sophisticated modeling based on the stochastic Liouville equation (SLE) is needed to access valuable information from NZFMR results. It has been shown that hyperfine and dipolar coupling interactions at atomic-scale defects affect the NZFMR line shape, but experimental parameters related to the detection method of NZFMR can also affect the nature of the response. Here, we demonstrate four distinct NZFMR detection methods in Si MOSFETs, which all access identical Si/SiO2 interface defects. In all four cases, we show that the line shape of the response is tunable based on experimental parameters alone. Using SLE-based modeling, we verify that time constants connected to physical carrier capture rates at the defect sites lead to these NZFMR line shape changes. The results demonstrate a method to extract some atomic-scale information for the purpose of defect identification. They also have broader applications to the continued development of ultra-sensitive magnetometers based on NZFMR in semiconductors. Additionally, the NZFMR effect in common Si-based devices may provide an inexpensive and accessible platform that mimics similar radical pair mechanisms that have become increasingly important in various biology fields.
A comparative study on the influences of fracture intersections on the prediction of rock mass permeability
Authors: Wang Xiaohong , Ge Qi , Chu Weijiang , Liu Ning , Wang Jingyong
Published: April 2024

Geometric predictive methods are efficient for determining the permeability of fractured rock masses, which evaluate the contribution of each fracture to the flow. However, the influences of fracture intersections are ignored during the calculation. In this study, influences of fracture intersections on the permeability prediction are studied. The result shows that the predicted flow rate can only have a good accuracy when there is an infinite-length fracture with a larger aperture. Based on this conclusion, three inferences for the applicability of geometric predictive methods are proposed: (a) for fracture networks where all fractures have infinite length, the predicted permeability can have a good accuracy; (b) for fracture networks containing both infinite-length and finite-length fractures, the predicted permeability is only accurate when the infinite-length fracture have a larger aperture; and (c) for fracture networks where all the fractures have finite length, the error rates of predicted permeability increase as the aperture ratios of fracture sets increase. Sixty-three sets of discrete fracture network models are generated for verification, and these numerical results validated our proposed inferences.
Prediction Challenge: Simulating Rydberg photoexcited cyclobutanone with surface hopping dynamics based on different electronic structure methods
Authors: Mukherjee Saikat , Mattos Rafael S. , Toldo Josene M. , Lischka Hans , Barbatti Mario
Published: April 2024

This research examines the nonadiabatic dynamics of cyclobutanone after excitation into the n → 3s Rydberg S2 state. It stems from our contribution to the Special Topic of the Journal of Chemical Physics to test the predictive capability of computational chemistry against unseen experimental data. Decoherence-corrected fewest-switches surface hopping was used to simulate nonadiabatic dynamics with full and approximated nonadiabatic couplings. Several simulation sets were computed with different electronic structure methods, including a multiconfigurational wavefunction [multiconfigurational self-consistent field (MCSCF)] specially built to describe dissociative channels, multireference semiempirical approach, time-dependent density functional theory, algebraic diagrammatic construction, and coupled cluster. MCSCF dynamics predicts a slow deactivation of the S2 state (10 ps), followed by an ultrafast population transfer from S1 to S0 (<100 fs). CO elimination (C3 channel) dominates over C2H4 formation (C2 channel). These findings radically differ from the other methods, which predicted S2 lifetimes 10–250 times shorter and C2 channel predominance. These results suggest that routine electronic structure methods may hold low predictive power for the outcome of nonadiabatic dynamics.
Thermodynamic stability and ionic conductivity in lithium–germanium binary system
Authors: Iosimovska Anastasiia V. , Maltsev Alexey P. , Chepkasov Ilya V. , Oganov Artem R.
Published: April 2024

Lithium–germanium binary compounds are promising anode materials for secondary lithium-ion batteries due to their high capacity, low operating voltage, and high electronic conductivity of lithiated Ge. For their successful application in batteries, it is essential to know the temperature stability of different Li–Ge phases and the variation of their ionic conductivity depending on the operating temperatures of the batteries. This work aims to comprehensively study the thermodynamic stability and ionic conductivity in Li–Ge binary compounds using a combination of first-principle computations and machine-learning interatomic potentials. We calculated convex hulls of the Li–Ge system at various temperatures and a temperature–composition phase diagram was obtained, delineating stability fields of each phase. Our calculations show that at temperatures higher than 590 K, LiGe undergoes a I41/a–P4/mmm transition, which leads to a change in the ionic conductivity. We show that all stable and metastable Li–Ge compounds have high ionic conductivity, but LiGe and Li7Ge12 have the lowest lithium diffusion. Trajectories of diffusion and Ge arrangements depend on lithium concentration. Based on advanced theoretical approaches, this study provides insights for the development of Li–Ge materials in lithium-ion and lithium-metal battery applications.
Enhanced controllable triplet proximity effect in superconducting spin–orbit coupled spin valves with modified superconductor/ferromagnet interfaces
Authors: Bregazzi A. T. , Ouassou J. A. , Coveney A. G. T. , Stelmashenko N. A. , Child A. , N'Diaye A. T. , Robinson J. W. A. , Dejene F. K. , Linder J. , Banerjee N.
Published: April 2024

In a superconductor/ferromagnet hybrid, a magnetically controlled singlet-to-triplet Cooper pair conversion can modulate the superconducting critical temperature. In these triplet superconducting spin valves, such control usually requires inhomogeneous magnetism. However, in the presence of spin–orbit coupling from an interfacial heavy metal layer, the singlet/triplet conversion rate and, thus, critical temperature can be controlled via the magnetization direction of a single homogeneous ferromagnet. Here, we report significantly enhanced controllable pair conversion to a triplet state in a Nb/Pt/Co/Pt superconducting spin valve in which Pt/Co/Pt is homogenously magnetized and proximity-coupled to a superconducting layer of Nb. The Co/Pt interface furthest away from Nb is modified by a sub-nanometer-thick layer of Cu or Au. We argue that the enhancement is most likely associated from an improvement of the Co/Pt interface due to the insertion of Cu and Au layers. Additionally, the higher normalized orbital moments in Au measured using x-ray magnetic circular dichroism shows that increasing spin–orbit coupling enhances the triplet proximity effect—an observation supported by our theoretical calculations. Our results provide a pathway to enhancing triplet pair creation by interface engineering for device development in superspintronics.