bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurocognitive effects of androgen deprivation therapy and new hormonal agents in a sample of patients with metastatic prostate cancer
Authors: Ihrig Andreas , Pernt Pascal Marino , Zschäbitz Stefanie , Huber Johannes , Friederich Hans-Christoph , Bugaj Till J. , Maatouk Imad
Published: July 2023

Introduction

Although the growing treatment landscape for metastatic prostate cancer (mPC) has revealed new opportunities, it has also provided challenges, such as undesirable side effects. The aim of the present study was to provide further data on domain-specific cognitive impairments in mPC patients with androgen deprivation therapy (ADT) and new hormonal agents.

Methods

Fifty-eight patients (71 ± 8 years) with mPC were investigated using a cross-sectional design. All patients had received some form of ADT (93% had received luteinizing hormone-releasing hormone (LHRH) analogs/antagonists), 66% had received chemotherapy, and 84% had received anti-resorptive therapy. We evaluated learning and memory, processing speed, and executive functions, as recommended by the International Cognition and Cancer Task Force, to determine neurocognitive deficits.

Results

Patients treated with ADT scored significantly lower on all neurocognitive tests and showed significantly more neurocognitive deficits (38–62%) than age-adjusted reference samples (16%, p < 0.05). Cognitive deficits were mild in most cases and predominantly affected visuomotor processing speed (48%). Moderate and severe deficits were found in 11% and 5% of patients, respectively, with word fluency as the predominant deficit (23%). No associations were found between the type or duration of treatment and the severity of cognitive deficits.

Conclusions

Treatment of mPC with ADT is correlated with neurocognitive deficits in several cognitive domains. Language skills and processing speed were most frequently impaired. However, a consistent pattern of cognitive impairment was not identified. Neurocognitive deficits should be considered in phase III and IV trials.

Trial registration

The study was registered in the German Clinical Trials Registry (DRKS00017727).
Upper airway morphology in adults with positional obstructive sleep apnea
Authors: Shi Xiaoxin , Sutherland Kate , Lobbezoo Frank , Berkhout Erwin , de Lange Jan , Cistulli Peter A. , Darendeliler M. Ali , Dalci Oyku , Aarab Ghizlane
Published: July 2023

Purpose

To compare the anatomical balance and shape of the upper airway in the supine position between adults with positional obstructive sleep apnea (POSA) and adults with non-positional OSA (NPOSA).

Methods

Adults diagnosed with OSA (apnea-hypopnea index (AHI) > 10 events/h) were assessed for eligibility. POSA was defined as the supine AHI more than twice the AHI in non-supine positions; otherwise, patients were classified as NPOSA. Cone beam computed tomography (CBCT) imaging was performed for every participant while awake in the supine position. The anatomical balance was calculated as the ratio of the tongue size to the maxillomandibular enclosure size. The upper airway shape was calculated as the ratio of the anteroposterior dimension to the lateral dimension at the location of the minimal cross-sectional area of the upper airway (CSAmin-shape).

Results

Of 47 participants (28 males, median age [interquartile range] 56 [46 to 63] years, median AHI 27.8 [15.0 to 33.8]), 34 participants were classified as having POSA (72%). The POSA group tended to have a higher proportion of males and a lower AHI than the NPOSA group (P = 0.07 and 0.07, respectively). After controlling for both sex and AHI, the anatomical balance and CSAmin-shape were not significantly different between both groups (P = 0.18 and 0.73, respectively).

Conclusion

Adults with POSA and adults with NPOSA have similar anatomical balance and shape of their upper airway in the supine position.

Trial registration

This study was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR Trial ACTRN12611000409976).
Head Orientation Modulates Vestibular Cerebellar Evoked Potentials (VsCEPs) and Reflexes Produced by Impulsive Mastoid and Midline Skull Stimulation
Authors: Govender Sendhil , Hochstrasser Daniel , Todd Neil PM , Colebatch James G
Published: July 2023

The cerebellum plays a critical role in the modulation of vestibular reflexes, dependent on input from proprioceptive afferents. The mechanism of this cerebellar control is not well understood. In a sample of 11 healthy human subjects, we investigated the effects of head orientation on ocular, cervical, postural and cerebellar short latency potentials evoked by impulsive stimuli applied at both mastoids and midline skull sites. Subjects were instructed to lean backwards with the head positioned straight ahead or held rotated in different degrees of yaw towards the right and left sides. Impulsive mastoid stimulation, a potent method of utricular stimulation, produced localised vestibular cerebellar evoked potentials (VsCEPs: P12-N17) which were strongly modulated by head orientation. The response was larger on the side opposite to the direction of head rotation and with stimulation on the side of rotation. In contrast, ocular VEMPs (oVEMPs: n10-p16) were present but showed little change with head posture, while cervical VEMPs (cVEMPs: p15-n23) were larger with the head held rotated away from the side of the recording. Postural effects with lateral vestibular stimulation were strongly modulated by head rotation, with more powerful effects occurring bilaterally with stimulation on the side of rotation. The duration of the postural EMG changes was similar to the post-excitation inhibition of the electrocerebellogram (ECeG), consistent with cerebellar participation. We conclude that head rotation selectively affects evoked vestibular reflexes towards different targets, consistent with their physiological roles. Changes in VsCEPs may contribute to the modulation of postural reflexes by the cerebellum.
Disinfection of vascular catheter connectors that are protected by antiseptic caps is unnecessary
Authors: Fillman Kelsey M. , Ryder Jonathan H. , Brailita Daniel M. , Rupp Mark E. , Cavalieri R. Jennifer , Fey Paul D. , Lyden Elizabeth R. , Hankins Richard J.
Published: July 2023

Objective:

Determination of whether vascular catheter disinfecting antiseptic-containing caps alone are effective at decreasing microbial colonization of connectors compared to antiseptic-containing caps plus a 5-second alcohol manual disinfection.

Setting:

The study was conducted in a 718-bed, tertiary-care, academic hospital.

Patients:

A convenience sample of adult patients across intensive care units and acute care wards with peripheral and central venous catheters covered with antiseptic-containing caps.

Methods:

Quality improvement study completed over 5 days. The standard-of-care group consisted of catheter connectors with antiseptic-containing caps cleaned with a 5-second alcohol wipe scrub prior to culture. The comparison group consisted of catheter connectors with antiseptic-containing caps without a 5-second alcohol wipe scrub prior to culture. The connectors were pressed directly onto blood agar plates and incubated. Plates were assessed for growth after 48-72 hours.

Results:

In total, 356 catheter connectors were cultured: 165 in the standard-of-care group, 165 in the comparison group, and 26 catheters connectors without an antiseptic-containing cap, which were designated as controls. Overall, 18 catheter connectors (5.06%) yielded microbial growth. Of the 18 connectors with microbial growth, 2 (1.21%) were from the comparison group, 1 (0.61%) was from the standard-of-care group, and 15 were controls without an antiseptic-containing cap.

Conclusions:

Bacterial colonization rates were similar between the catheter connectors cultured with antiseptic-containing caps alone and catheter connectors with antiseptic-containing caps cultured after a 5-second scrub with alcohol. This finding suggests that the use of antiseptic-containing caps precludes the need for additional disinfection.
Digital fashionistas: young women, wealth-in-followers and matronage in Yaoundé, Cameroon
Authors: Majczak Ewa
Published: July 2023

Against the background of post-Cold War trade and media liberalization, this article examines how young women living in Yaoundé, Cameroon, share digital images of their crafted styles via WhatsApp. Such sharing is an act of influence usually aimed at building the woman’s name as a digital ‘fashionista’, in that it constitutes a virtual potential for persuading others to copy one’s style. When this potential is actualized among women of status and rank, young women can fashion relations of matronage, opening up avenues of upward social mobility. To reach out to women of status and rank, young women circulate images of their styles to mobilize digital follower networks of peers, kin and strangers, drawing on their skills, status and knowledge. This mobilization in turn relies on the actual and potential benefits that sharing a fashionista image can bring to the follower. Thus, I argue, interdependencies between stylish leaders and their followers are key to making and maintaining a name as a digital fashionista. This article contributes to the literature on fashion and social mobility in West Africa by showing how the circulation of digital images over social media networks generates potentialities for young women living in Yaoundé to fashion matronage relations and social mobility. More broadly, the framing of followers as a form of wealth-in-people provides a critique of the neoliberal market valuation of social media influencers, illuminating alternative regimes of valuation that inform digital influencer economies.
Crustal Structure Across the Central Dead Sea Transform and Surrounding Areas: Insights Into Tectonic Processes in Continental Transforms
Authors: ten Brink U. S. , Levi E. , Flores C. H. , Koulakov I. , Bronshtein N. , Ben‐Avraham Z.
Published: July 2023

New geophysical profiles across the central Dead Sea Transform (DST) near the Sea of Galilee, Israel, and surrounding highlands, augmented by static stress modeling, allow us to study continental transform plate deformation. The DST separates a ∼10 km thick sedimentary column above a thinned (16–23 km) crust to the west from a ∼7 km column above a ∼30‐km thick crust to the east. Crustal thinning starts under the DST, as observed also farther south, indicating that the DST is indeed located along the boundary between the Arabian plate and its continental margin. Moho step here is gradual. The DST's eastern shoulder dips westward toward the DST unlike the upward flexed shoulder observed farther south, perhaps delineating the northern limit of a thinner and hotter lithosphere. The shape of the Sea of Galilee is modeled as an asymmetric pull‐apart basin formed by a left‐lateral stepover of 2.6 km between slightly divergent and underlapping strike‐slip fault strands dipping 70° to the west. Reflection data indicate that these strands are not connected. Several fault traces within the Sea of Galilee have previously been suggested to carry part of the relative plate motion. However, given slip along the main DST faults, Coulomb stress will increase only on fault portions in the northern part of the lake, in accord with the geographical distribution of seismicity, suggesting that these faults are likely secondary. Mismatch between the DST strand locations in the geophysical profiles and the subsidence model, may reflect temporal changes in fault geometry.
Pure spin current in a cobalt phthalocyanine chain induced by the photogalvanic effect
Authors: Liu Xiaojie , Tao Bairui , Wang Yin , Yin Haitao
Published: July 2023

A pure spin current can be generated in cobalt phthalocyanine chain by the photogalvanic effect when the magnetic moment directions of the left and right parts of the chain are anti-parallel.
An eco-friendly one-pot extraction process for curcumin and its bioenhancer, piperine, from edible plants in exosome-like nanovesicles
Authors: Kumar Meghana N. , Kalarikkal Sreeram Peringattu , Bethi Cathrine M. S. , Singh Sukriti Narendra , Narayanan Janakiraman , Sundaram Gopinath M.
Published: July 2023

Preparation of hybrid exosom-like nanovesicles from turmeric and pepper with novel attributes.
Green and sustainable natural derived polysulfides for a broad range of applications
Authors: Zhang Yidan , Seidi Farzad , Ahmad Mehraj , Zheng Ling , Cheng Long , Huang Yang , Xiao Huining
Published: July 2023

The review discusses the fabrication strategies for bio-based polysulfides as well as their applications in lithium-sulfur batteries, heavy metal removal, agriculture, water/oil separation, and as Portland cement alternatives.
Synthesis of a new benzoate bridged NNO tethered copper(ii) complex: exploration of its bio, catalytic and anticancer activities
Authors: Mandal Subrata , Naskar Rahul , Mukherjee Rimi , Mondal Apurba Sau , Das Akash , Murmu Nabendu , Mondal Tapan K.
Published: July 2023

The catalytic and biological activities of a new benzoate bridged NNO tethered homo-binuclear copper(ii) complex have been explored.
Microwave-synthesized narrow emitting carbon dots and their tunable fluorescence for sensing applications
Authors: Wei Xiao-Lan , Shi Qin-Lin , Jiang Lan , Qin Yu
Published: July 2023

Fluorescent carbon dots with narrow emissions were simply synthesized by open microwave-heating of ethylene glycol solution of phloroglucinol and thiosulfate.
Evaluation of DeGIR registry data on endovascular treatment of cerebral vasospasm in Germany 2018–2021: an overview of the current care situation
Authors: Neumann Alexander , Weber Werner , Küchler Jan , Schacht Hannes , Jensen-Kondering Ulf , Berlis Ansgar , Schramm Peter
Published: July 2023

Background Evaluation of endovascular therapies for cerebral vasospasm (CVS) documented in the DeGIR registry from 2018–2021 to analyse the current clinical care situation in Germany.

Methods Retrospective analysis of the clinical and procedural data on endovascular spasm therapies (EST) documented anonymously in the DeGIR registry. We analysed: pre-interventional findings of CTP and consciousness; radiation dose applied, interventional-technical parameters (local medication, devices, angiographic result), post-interventional symptoms, complications and mortality.

Results 3584 patients received a total of 7628 EST (median age/patient: 53 [range: 13–100, IQR: 44–60], 68.2 % women) in 91 (2018), 92 (2019), 100 (2020) and 98 (2021) centres; 5388 (70.6 %) anterior circulation and 378 (5 %) posterior circulation (both involved in 1862 cases [24.4 %]). EST was performed once in 2125 cases (27.9 %), with a mean of 2.1 EST/patient. In 7476 times, purely medicated EST were carried out (nimodipine: 6835, papaverine: 401, nitroglycerin: 62, other drug not specified: 239; combinations: 90). Microcatheter infusions were documented in 1132 times (14.8 %). Balloon angioplasty (BA) (additional) was performed in 756 EST (9.9 %), other mechanical recanalisations in 154 cases (2 %) and stenting in 176 of the EST (2.3 %). The median dose area product during ET was 4069 cGycm² (drug: 4002/[+]BA: 8003 [p < 0.001]). At least 1 complication occurred in 95 of all procedures (1.2 %) (drug: 1.1 %/[+]BA: 4.2 % [p < 0.001]). Mortality associated with EST was 0.2 % (n = 18). After EST, overall improvement or elimination of CVS was found in 94.2 % of cases (drug: 93.8 %/[+]BA: 98.1 % [p < 0.001]). In a comparison of the locally applied drugs, papaverine eliminated CVS more frequently than nimodipine (p = 0.001).

Conclusion EST have a moderate radiation exposure and can be performed with few complications. Purely medicated EST are predominantly performed, especially with nimodipine. With (additional) BA, radiation exposure, complication rates and angiographic results are higher or better. When considering drug EST alone, there is evidence for an advantage of papaverine over nimodipine, but a different group size has to be taken into account. In the analysis of EST, the DeGIR registry data are suitable for answering more specific questions, especially due to the large number of cases; for this purpose, further subgroupings should be sought in the data documentation.

Key points: 

Citation Format
Synthesis of β-Hydroxyhydrophosphonic Acids from Inorganic Sodium Hypophosphite
Authors: Yang Shang-Dong , Qian Dang-Wei , Yang Jin , Wang Gang-Wei
Published: July 2023

An efficient approach to access β-hydroxyhydrophosphonic acid derivatives is reported by ring-opening reaction of readily available epoxides with green, inexpensive, and safe inorganic salt sodium hypophosphate as the phosphorus source in the presence of silver trifluoromethanesulfonate as the catalyst. The reaction is achieved under simple operation and exhibits excellent selectivity as well as good functional group compatibility.
Use of Sodium Channel Blockers in the Thr226Met Pathologic Variant of SCN1A: A Case Report
Authors: Nájera-Chávez Brenda Carolina , Seeber Lea , Goldhahn Klaus , Panzer Axel
Published: July 2023

The Thr226Met pathologic variant of the SCN1A gene has been associated with the clinical development of an early infantile developmental and epileptic encephalopathy (EIDEE) different from Dravet's syndrome. The electrophysiological mechanisms of the mutated channel lead to a paradoxical gain and loss of function. The use of sodium channel blockers (SCB) that counteract this gain of function has been described in previous studies and they can be safely administered to patients carrying mutations in other sodium channel subtypes without causing a worsening of seizures. We report the use of SCB in a child harboring the Thr226Met pathologic variant of SCN1A with early-onset pharmaco-resistant migrating seizures, as well as developmental delay. Lacosamide led to a dramatic reduction in seizure frequency; however, only a mild improvement in the epileptic activity depicted by electroencephalography (EEG) was achieved. The introduction of carbamazepine as an add-on therapy led to a notable reduction in epileptic activity via EEG and to an improvement in sensorimotor development. Despite the overall clinical improvement, the patient developed febrile seizures and a nonepileptic jerking of the right hand. In this case of EIDEE with the Thr226Met variant, we demonstrate a beneficial pharmacological intervention of SCB in contrast to findings described in current literature. Our report encourages the cautious use of SCB at early stages of the disease in patients carrying this pathologic variant.
The Role of Intraoperative Radiotherapy Treatment of Locally Advanced Rectal Cancer
Authors: Amarnath Sudha R.
Published: July 2023

Intraoperative radiation therapy (IORT) has been used in the treatment of locally advanced and recurrent rectal cancers for the last several decades. Given the heterogeneity of patients treated and different indications for use and dosing at different institutions, it has been difficult to discern if IORT adds any appreciable benefit to standard of care therapies. Herein, the rationale for IORT in rectal cancer is discussed along with the most modern and best available data in 2023. IORT is likely indicated in patients with locally advanced and locally recurrent rectal cancer with threatened margins (R0 or R1 resection) to help improve local control. High-quality imaging and multidisciplinary discussion are necessary to ensure optimal patient selection. Appropriate counseling of the patient and excellent team communication are of the utmost importance given the challenging nature of these cases and the prognostic implications of R1 and R2 resections in this patient population.
Causal interaction in high frequency turbulence at the biosphere–atmosphere interface: Structure–function coupling
Authors: Hernandez Rodriguez Leila Constanza , Kumar Praveen
Published: July 2023

At the biosphere–atmosphere interface, nonlinear interdependencies among components of an ecohydrological complex system can be inferred using multivariate high frequency time series observations. Information flow among these interacting variables allows us to represent the causal dependencies in the form of a directed acyclic graph (DAG). We use high frequency multivariate data at 10 Hz from an eddy covariance instrument located at 25 m above agricultural land in the Midwestern US to quantify the evolutionary dynamics of this complex system using a sequence of DAGs by examining the structural dependency of information flow and the associated functional response. We investigate whether functional differences correspond to structural differences or if there are no functional variations despite the structural differences. We base our analysis on the hypothesis that causal dependencies are instigated through information flow, and the resulting interactions sustain the dynamics and its functionality. To test our hypothesis, we build upon causal structure analysis in the companion paper to characterize the information flow in similarly clustered DAGs from 3-min non-overlapping contiguous windows in the observational data. We characterize functionality as the nature of interactions as discerned through redundant, unique, and synergistic components of information flow. Through this analysis, we find that in turbulence at the biosphere–atmosphere interface, the variables that control the dynamic character of the atmosphere as well as the thermodynamics are driven by non-local conditions, while the scalar transport associated with CO2 and H2O is mainly driven by short-term local conditions.
Non-contact cardiopulmonary signal monitoring based on magnetic eddy current induction
Authors: Kong Li , Li Gang , Wang Yunyi , Cheng Leiyang , Lin Ling
Published: July 2023

The magnetic eddy current induction method has become an excellent solution for building home cardiopulmonary monitoring systems because of its non-contact and unobtrusive characteristics, but it has problems such as low precision and complex extraction of cardiopulmonary signals. Therefore, this paper designs a magnetic eddy current sensing system based on a Field Programmable Gate Array that can realize simultaneous real-time monitoring of cardiopulmonary signals. This system adopts a magnetic eddy current sensor design scheme that can improve the amount of cardiopulmonary information in the sensing signal. In addition, it uses a signal acquisition scheme that combines an inductance-to-digital converter (LDC) and oversampling technology to improve the resolution and signal-to-noise ratio of the sensing signal. Moreover, an optimized adaptive discrete wavelet transform algorithm is proposed in this system, which can realize the effective separation and extraction of cardiopulmonary signals in different respiration states. Comparing this system with the medical monitor, the cardiopulmonary signals obtained by the two have good consistency in the time-frequency domain. Under low motion, respiration rate and heart rate detected by this system are within the confidence interval of the 95% limit of agreement; the relative errors are less than 2.63% and 1.37%, respectively; and the accuracy rates are greater than 99.30% and 99.60%, respectively. In addition, an experiment with an asthmatic patient showed that the system still has good detection performance under pathological conditions and can monitor abnormal conditions such as coughing.
Magnetic properties of Cr-doped VO2 thin films in tetragonal phase of rutile and their synchrotron-based electronic structures
Authors: Kumar A. , Zzaman M. , Kumari A. , Franklin J. B. , Srivastava S. , Verma V. K. , Amemiya K. , Miura Y. , Kandasami A. , Singh V. R.
Published: July 2023

The present study is focused on the investigation at 400 K of the tetragonal-rutile phase of Cr-doped VO2 (CVO) thin films grown by pulsed laser deposition. Synchrotron-based x-ray measurements of both the surface-sensitive total electron yield (TEY) and bulk-sensitive total fluorescence yield (TFY) modes were used to investigate the pristine and Cr-doped VO2 (5%, 10%, 20%, and 30% of atomic weight). The structural analysis and purity of the crystalline phase of the as-deposited films are manifested via grazing incidence x-ray diffraction patterns, which confirm the tetragonal-rutile phase. The purity of the phase is also confirmed by the presence of Eg-mode phonons in the Raman spectra and its deconvolution reflects on the oxygen-mediated electronic/vibrational transitional effect. A clear hysteretic behavior obtained through vibrating sample magnetometry strongly suggests the ferromagnetic interaction in the thin films of CVO. The local-electronic property of the samples is examined using x-ray absorption spectroscopy (XAS) in TEY and TFY modes where the difference in the configured helicity photons resulted in the fine spectra of x-ray magnetic circular dichroism (XMCD). XAS and XMCD measurements performed at V L2,3 and Cr L2,3 edges explicitly demonstrate the ferromagnetism in the thin films of CVO. The strong hybridization between V 3d and Cr 3d states with O 2p states is evident from the spectra of the O K-edge, resulting in the onset of the cation-pair formation V5+–Cr3+, which is ferromagnetic by means of double-exchange interaction. The theoretical calculation of density functional theory made upon Vienna ab initio simulation package suggests that CVO is in a mixed state of a ferromagnetic-insulator and a half-metallic ferromagnet.
Generalized Heisenberg–Virasoro algebra and matrix models from quantum algebra
Authors: Melong Fridolin , Wulkenhaar Raimar
Published: July 2023

In this paper, we construct the Heisenberg–Virasoro algebra in the framework of the R(p,q)-deformed quantum algebras. Moreover, the R(p,q)-Heisenberg–Witt n-algebras is also investigated. Furthermore, we generalize the notion of the elliptic Hermitian matrix models. We use the constraints to evaluate the R(p,q)-differential operators of the Virasoro algebra and generalize it to higher order differential operators. Particular cases corresponding to quantum algebras existing in the literature are deduced.
Statistical performance of local attractor dimension estimators in non-Axiom A dynamical systems
Authors: Pons Flavio , Messori Gabriele , Faranda Davide
Published: July 2023

We investigate various estimators based on extreme value theory (EVT) for determining the local fractal dimension of chaotic dynamical systems. In the limit of an infinitely long time series of an ergodic system, the average of the local fractal dimension is the system’s global attractor dimension. The latter is an important quantity that relates to the number of effective degrees of freedom of the underlying dynamical system, and its estimation has been a central topic in the dynamical systems literature since the 1980s. In this work, we propose a framework that combines phase space recurrence analysis with EVT to estimate the local fractal dimension around a particular state of interest. While the EVT framework allows for the analysis of high-dimensional complex systems, such as the Earth’s climate, its effectiveness depends on robust statistical parameter estimation for the assumed extreme value distribution. In this study, we conduct a critical review of several EVT-based local fractal dimension estimators, analyzing and comparing their performance across a range of systems. Our results offer valuable insights for researchers employing the EVT-based estimates of the local fractal dimension, aiding in the selection of an appropriate estimator for their specific applications.
Step unbunching phenomenon on 4H-SiC (0001) surface during hydrogen etching
Authors: Sakakibara Ryotaro , Bao Jianfeng , Yuhara Keisuke , Matsuda Keita , Terasawa Tomo-o , Kusunoki Michiko , Norimatsu Wataru
Published: July 2023

We here report a step unbunching phenomenon, which is the inverse of the phenomenon of step bunching. When a 4H-SiC (0001) surface is annealed at a high temperature, step bunching arises due to the different velocities of the step motion in adjacent steps, resulting in steps with a height of more than several nanometers. We found that the bunched steps, thus, obtained by hydrogen etching in an Ar/H2 atmosphere were “unbunched” into lower height steps when annealed subsequently at lower temperatures. This unbunching phenomenon can be well explained by the consequence of the competition between energetics and kinetics. Our findings provide another approach for the surface smoothing of SiC by hydrogen etching and may give significant insight into the application of SiC power devices and two-dimensional materials growth techniques in general.
Energetic characterization during plasma electrolytic polishing of cemented tungsten carbide
Authors: An Sehoon , Hansen Luka , Wolff Thorben , Foest Rüdiger , Fröhlich Maik , Quade Antje , Stankov Marjan , Kersten Holger
Published: July 2023

Electrical and thermal measurements were conducted during the plasma electrolytic polishing (PEP) of cemented tungsten carbide (WC-Co) materials to characterize energetic aspects of the process in relation to the temporal development of the gaseous layer near the workpiece. The power transferred to the workpiece is determined using a calorimetric probe and employing the time derivative of the temperature curve. It shows distinct heating phases due to the generation of the gaseous layer. At the beginning of the process, a typical power of 367 ± 17 W is transferred to the workpiece of a surface area of 14 cm2. At longer process times, a stabilized gaseous layer limits the power transferred to the workpiece to 183 ± 3 W. In an attempt to describe the heat transferred to the electrolyte, the electrolyte temperature was measured using a thermocouple situated 15 mm away from the workpiece. The local electrolyte temperature increases from 70 to 81 °C for an immersion depth of 20 mm. Moreover, the spatiotemporal development of the electrolyte temperature was obtained by 2D-hydrodynamic modeling using COMSOL Multiphysics®. The modeling results for the local temporal temperature development are in excellent agreement with the experimental values when the turbulent model is applied up to t = 65 s. Afterward, the laminar model leads to a better agreement. Furthermore, line scan x-ray photoelectron spectroscopy revealed that aliphatic carbon was preferentially removed. Only a slight compositional gradient in the vertical direction after the PEP process was observed.
Large eddy simulation study of the airflow characteristics in a human whole-lung airway model
Authors: Jing Hao , Ge Haiwen , Wang Li , Zhou Qizhi , Chen Liang , Choi Sanghun , Cui Xinguang
Published: July 2023

Studying airflow characteristics in the human respiratory system is important for understanding the properties of the aerosol transport and deposition. This study first constructed a human whole-lung airway model (WLAM) with random features extending from the mouth to the 13th generation bronchus. The large eddy simulation method is utilized to investigate the features of both the averaged airflow fields and flow unsteadiness under inspiratory flow rates of 15 and 30 l/min, respectively. The results reveal the following novel findings: (1) secondary flow strength is not monotonically changing throughout the respiratory tract, depending on the local flow state and geometry, which allows for strong secondary flow motion even in the G13 bronchial airway. (2) In the upper airway, the peak distribution of turbulent kinetic energy (TKE) is due to in-plane secondary flow shear and longitudinal flow shear; local kinetic energy plays a vital role in the persistence of unsteadiness throughout the bronchial tree, which allows instability to still exist even in the bronchial airway with low Reynolds number. (3) TI is more dependent on the local flow state and geometric structure than TKE. These findings indicate that secondary flow and airflow unsteadiness in the thin bronchial airway are far stronger than previously reported and cannot be neglected. Therefore, further studies should investigate airflow unsteadiness in the thin bronchial airway using a suitable WLAM instead of a segmented bronchial airway model.
Deformation of a Hele–Shaw drop undergoing quadratic flow
Authors: Razzaghi A. , Ramachandran A.
Published: July 2023

A Hele–Shaw quadratic flow in the form of a six-port microfluidic device is employed to study the deformation of a single channel-spanning or Hele–Shaw Newtonian drop suspended in a Newtonian medium. An initially circular drop in a quadratic flow deforms into a regular triarcle, i.e., a rounded-corner triangle. Theoretically, the deformation is calculated in the limit of small capillary number, which is defined as Ca=Cμa4/(4γb2), where C is the quadratic flow rate, μ is the suspending fluid viscosity, a is the drop radius, γ is the interfacial tension, and b is the channel depth. The theory matches reasonably well with the experiment for small capillary numbers. This is the new way of deforming drops on a Hele–Shaw quadratic platform experimentally and may lead to measurements such as complex interfacial properties and breakup.
Demonstration of electromagnetic enhancement correlated to optical absorption of single plasmonic system coupled with molecular excitons using ultrafast surface-enhanced fluorescence
Authors: Itoh Tamitake , Yamamoto Yuko S.
Published: July 2023

The relationship between the electromagnetic (EM) enhancement of the optical responses of molecules and plasmon resonance has been investigated using Rayleigh scattering or the extinction spectra of plasmonic systems coupled with molecular excitons. However, quantum optics predicts that the EM enhancement of such optical responses, e.g., fluorescence, Raman, and their nonlinear counterparts, is related directly to optical absorption and indirectly to Rayleigh scattering and extinction. To demonstrate this prediction, a micro-spectroscopic method for obtaining Rayleigh scattering, extinction, absorption, and EM enhancement is developed using single-coupled plasmonic systems composed of silver nanoparticle dimers and dye molecules. The EM enhancement is derived from ultrafast surface-enhanced fluorescence. An evaluation of the spectral relationships demonstrates that the EM enhancement can be reproduced better by absorption than by Rayleigh scattering or extinction. This reproduction is phenomenologically confirmed by numerical calculations based on classical electromagnetism, indicating the importance of absorption spectroscopy in coupled plasmonic systems for evaluating EM enhancement.
Long-wave infrared integrated resonators in the 7.5–9 μm wavelength range
Authors: Koompai Natnicha , Nguyen Thi Hao Nhi , Turpaud Victor , Frigerio Jacopo , Falcone Virginia , Calcaterra Stefano , Lucia Luca , Bousseksou Adel , Colombelli Raffaele , Coudevylle Jean-Rene , Bouville David , Alonso-Ramos Carlos , Vivien Laurent , Isella Giovanni , Marris-Morini Delphine
Published: July 2023

We present broadband on-chip resonators based on SiGe graded-index waveguides operating in the long-wave infrared spectral range from 7.5 to 9.0 μm wavelength range. A quality factor up to 105 has been measured, while an intrinsic quality factor of 1.13 × 105 has been extracted from the measurements. Thermal tuning of the phase in the micro-ring has been used to overcome the limitation of the experimental setup in terms of spectral resolution. These results pave the way toward the development of integrated frequency comb operating in the long-wave infrared range.
Hot crystals of thermo-responsive particles with temperature dependent diameter in the presence of a temperature gradient
Authors: Karmakar Rahul , Chakrabarti J.
Published: July 2023

Structure formation under non-equilibrium steady state conditions is poorly understood. A non-equilibrium steady state can be achieved in a system by maintaining a temperature gradient. A class of cross-linked microgel particles, such as poly-N-iso-propylacrylamide, is reported to increase in size due to the adsorption of water as the temperature decreases. Here, we study thermo-responsive particles with a temperature sensitive diameter in the presence of a temperature gradient, using molecular dynamics simulations with the Langevin thermostat. We find long-ranged structural order using bond order parameters in both cold and hot regions of the system beyond a certain diameter ratio of the cold and hot particles. This is due to an increase in packing and pressure in both regions. Our observations might be useful in understanding ordered structures under extreme conditions of a non-equilibrium steady state.
Aerodynamic performance of a characteristic airfoil at low-Reynolds number and transonic flow under Mars sand-containing environment
Authors: Liu Jiachun , Li Deyou , Zuo Zhigang , Liu Chen , Wang Hongjie
Published: July 2023

The propeller tip of an unmanned aerial vehicle on Mars operates at a low-Reynolds number (Re = 1–5 × 104) and transonic velocity range (Ma = 0.7–1.2). Generally, this implies flow separation and shock waves in the flow field. Furthermore, the impact of Martian atmospheric sand particles significantly affects the aerodynamic performance, and numerical simulations of this issue have received increasing attention recently. Aimed at a characteristic airfoil, the study of a low-Reynolds number transonic flow and the influence of sand-containing flow on airfoil aerodynamic performance were analyzed in this study. The discrete phase model was adopted to simulate the two-phase flow considering Re = 8100–56 800 and Ma = 0.2–1.4. The results indicate that, compared with the atmospheric environment on Earth, the low-pressure atmosphere on Mars can delay the generation of the surface shock wave of the airfoil as well as alter the shock wave structure, significantly increasing the lift-to-drag ratio at high subsonic velocities (Ma = 0.6–0.8). Moreover, due to the weak compressive wave generated at the separation position, the low-pressure atmosphere weakens the strength of the trailing-edge oblique shock wave and reduces the drag when Ma = 0.9–1.4. Compared with a sand-free environment, sand-containing flow can affect the separation and transition positions of laminar separation bubbles, in addition to alter the shock wave structure. At different Mach numbers, the lift and drag of the airfoil first increased and then decreased as the sand particles flowed in the horizontal direction during the entire process of particles entering and exiting the airfoil flow field.
Air-bubble entrainment by translating turbulent jets in stagnant water
Authors: Amin Mahmud R. , Zhu David Z. , Rajaratnam Nallamuthu
Published: July 2023

This paper presents an experimental study on air-bubble entrainment in quiescent water by translating circular turbulent jets. The jet diameters, plunging heights, impact velocities, and translating velocities were varied during the experiments to investigate their relative effect on the bubble characteristics. The experimental observations reveal that the jet translation affects the air bubble entrainment mechanism and the distribution of bubble size. A rotating cavity forms around the plunging jet due to the translation of the jet. Depending on the translating velocity, the air bubble emanates from the cusp of the cavity and the downstream water surface meniscus with the jet. The bubble swarm produced by the translating jet exhibits vortex shedding with Strouhal numbers between 0.22 and 0.27, comparable to a circular cylinder in cross-flow. The peak of the bubble size distribution varies between 0.5 and 1.5 mm, while the Sauter mean diameter varies between 1.8 and 2.8 mm. The maximum penetration depth of bubbles is found to be a function of the jet impact to translating velocity ratio, and the Capillary number of the air–water interface. The spatial distribution of bubbles along the plume cross section exhibits Gaussian distributions. Finally, the terminal rising velocity of the bubbles shows no obvious effect of the jet translation.
Polarized vdW Schottky photodiode with high fill-factor and polarization ratio
Authors: Bu Nabuqi , Huang Jianming , Chen Shengdi , Zhu Lingyu , Yu He , Li Ling , Li Jingbo , Huo Nengjie
Published: July 2023

Against the background of a variety of polarized optical applications, a great number of polarization-sensitive photodetectors based on anisotropic two-dimensional (2D) materials and their heterojunctions have been proposed. However, the low polarization ratio (PR), describing the response sensitivity on the polarization angle of the incident light, is still demanding to be solved. In this work, we demonstrate a van der Waals (vdW) Schottky photodiode comprising 2D semiconductor InSe and semimetal 1T′-MoTe2 for the linearly polarized photodetection. The device exhibits obvious photovoltaic characters with a maximum open circuit voltage (Voc) of 0.51 V and fill factor (FF) up to 0.78, which is the highest value in the vdW heterojunction-based photovoltaic device. Due to the anisotropic in-plane structure of 1T′-MoTe2, our photodiode also shows a strong polarization-sensitive photodetection with a PR value up to ∼22, enabling the practical applications in angle-dependent photodetector and image sensors. This work reports a vdW Schottky heterojunction for polarized photodiode with high FF and polarization ratio, toward the polarization-dependent photovoltaic applications.
Fractional mode charge in Cn-symmetric higher-order topological crystalline insulators
Authors: Zheng Taotao , Hu Kaiqi , Zhou Yuxiang , Xu Chudong , Lu Ming-Hui
Published: July 2023

The measurement of topological insulators is usually achieved by measuring spectra, which is inadequate in higher-order topological insulators because the separation of bandgaps may be blurred, such as body boundaries and corner state hybridization, and the above measurement requires that the energy of the topological mode must be located in the bulk bandgap to be measured. Recent experiments have shown a strong relationship between the fractional mode charge and the location of the Wannier center in the crystal body. The fractional quantization of the corner charge originates from the filling anomaly, and the fractional mode charge can be calculated from experimental measurements of the local density of states to describe the topological state of the system, which has been demonstrated in optical systems. We have achieved a similar effect in acoustics by utilizing a coupled acoustic-cavity system featuring C3, C4, and C6 symmetries for simulation. Furthermore, we extended our study to 3D third-order topological crystalline insulators to validate the fractional-corner charge approach. The simulation and theoretical results demonstrate that the fractional mode charge can clearly identify the high-order topology, even without gap states.
On heterogeneous diffusion processes and the formation of spatial–temporal nonlocality
Authors: Arkashov N. S. , Seleznev V. A.
Published: July 2023

Heterogeneous diffusion processes defined as a solution to the overdamped Langevin equation with multiplicative noise, the amplitude of which has a power-law space-dependent form, are studied. Particular emphasis is on discrete analogs of these processes, for which, in particular, an asymptotic estimate of their variance behavior in time is obtained. In addition, a class of processes formed by deformation of the discrete analog of the fractional Brownian motion using the Cantor ladder and its inverse transformation is considered. It is found that such a class turns out to be close in structure to discrete analogs of heterogeneous processes. This class of processes allows us to illustrate geometrically the emergence of sub- and superdiffusion transport regimes. On the basis of discrete analogs of heterogeneous processes and memory flow phenomenology, we construct a class of random processes that allows us to model nonlocality in time and space taking into account spatial heterogeneity.
Failure mechanism and pressure resistance investigation of divergent magnetic fluid seals with staggered pole teeth
Authors: Liu Yang , Yang Xiaolong , Shi Miao , Han Leigang , Li Decai
Published: July 2023

This paper investigates the failure mechanism of a divergent magnetic fluid seal (MFS) with staggered pole teeth (SPT). By pole teeth, we mean the teeth machined on the inner ring surface of the pole pieces, which have a magnetic field gathering effect. A sealing apparatus capable of directly visualizing the surface deformation of the magnetic fluid film is developed, and the sealing mechanism is studied through experiments. The magnetic field distribution of the sealing apparatus is numerically analyzed to calculate its theoretical value, and this is compared against the experimental observations. The impacts of the eccentricity distance of the axial pole teeth and the addition of magnetic insulation materials on the pressure resistance of the MFS–SPT structure are investigated. The results show that, during the pressure loading process, the magnetic fluid moves to the low-pressure side. When the seal fails, micro-leakage and complete leakage occur successively in the MFS–SPT structure. There is good agreement between the experimental and theoretical pressure resistance of a divergent MFS–SPT. As the eccentricity distance of the axial pole teeth increases, the pressure resistance of the divergent MFS–SPT is enhanced. The sealing performance of the divergent MFS–SPT structure is improved when a magnetic insulation material is added to the grooves of the axial teeth.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: July 2023

In order to supplement manufacturers’ information, this department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials that supersede earlier data or suggest new research applications.
Stochastic Gradient Descent and Anomaly of Variance-Flatness Relation in Artificial Neural Networks
Authors: Xiong Xia , Chen Yong-Cong , Shi Chunxiao , Ao Ping
Published: July 2023

Stochastic gradient descent (SGD), a widely used algorithm in deep-learning neural networks, has attracted continuing research interests for the theoretical principles behind its success. A recent work reported an anomaly (inverse) relation between the variance of neural weights and the landscape flatness of the loss function driven under SGD [Feng Y and Tu Y Proc. Natl. Acad. Sci. USA
118 e2015617118 (2021)]. To investigate this seeming violation of statistical physics principle, the properties of SGD near fixed points are analyzed with a dynamic decomposition method. Our approach recovers the true “energy” function under which the universal Boltzmann distribution holds. It differs from the cost function in general and resolves the paradox raised by the the anomaly. The study bridges the gap between the classical statistical mechanics and the emerging discipline of artificial intelligence, with potential for better algorithms to the latter.
Tunable strong plasmon–exciton coupling based modulator employing borophene and deep subwavelength perovskite grating
Authors: Yan Xiao-Fei , Lin Qi , Wang Ling-Ling , Liu Gui-Dong
Published: July 2023

Two-dimensional materials support deeply confined and tunable plasmonic modes, which have great potential for achieving device miniaturization and flexible manipulation. In this paper, we propose a diffraction-unlimited system (period ≈ λ/20) composed of borophene layer and perovskite grating to investigate the strong coupling between the borophene guiding plasmon (BGP) and perovskite exciton (PE) modes. The resonant energy of the BGP mode could be electrically tuned to match the energy of the PE mode, and a remarkable Rabi splitting is attained under zero-detuning conditions. The splitting energy could reach 230 meV due to the strong field enhancement provided by the BGP mode. Taking advantage of the proposed electrically tunable hybrid system, not only is the reflective amplitude modulation depth up to 99.9%, but the 1.76π phase range modulation is achieved. Furthermore, by increasing the distance between the borophene layer and perovskite grating, a passive parity-time symmetry breaking could be observed with the vanished energy splitting. Our results deepen our understanding of light–matter interactions at the sub-wavelength scale and provide a guideline for designing active plasmonic devices.