bluuebunny/crossref_metadata_2025 huggingface dataset:
Langerhans cell histiocytosis involving the temporal bone with destruction and subsequent reossification of the bony labyrinth boundaries
Authors: Döring Katja , Ivanyi Philipp , Lanfermann Heinrich , Warnecke Athanasia , Giesemann Anja
Published: February 2024

Purpose With an incidence between 1–9/100 000 per year, Langerhans cell histiocytosis (LCH) is a rather rare disease from the hemato-oncologic disease spectrum (Hayes et al. 2009). The tumorlike disease with proliferation of histiocytic cells may manifest as localized to one organ or disseminated with infiltration of a wide variety of organs. Approximately 25–30 % of these cases show involvement of the temporal bone (Ni et al. 2017).

Case Description With vertigo persisting for three years, chronic mastoiditis, and acute progressive hearing loss bilaterally (r > l) for three weeks, a 41-year-old woman presented at an emergency department. The DVT showed extensive bony destruction of large parts of the temporal bone on both sides, involving the vestibular organ, the cochlea, and the internal auditory canal. To confirm the suspicion of a systemic inflammatory process, a PE was performed from the mastoid with bioptic confirmation of an LCH. Systemic therapy was initiated. Post-therapeutic imaging showed almost complete remission with reossification of the preexisting defect zones and the internal auditory canal and labyrinth structures again showed bony margins. Clinically, there was an improvement of the vegetative symptoms with remaining bilateral sensorineural hearing loss.

Discussion LCH of the temporal bone is a rare and often misdiagnosed disease due to its nonspecific clinical presentation. Awareness of temporal bone LCH and its occurrence in adults is essential for accurate and consistent diagnosis.

Key Points:
Energy Metabolism in Residents in the Low- and Moderate Altitude
Regions of Central Asia with MAFLD and Type 2 Diabetes Mellitus
Authors: Toktogulova Nurgul , Breidert Matthias , Eschbach Judith , Kudaibergenova Indira , Omurzakova Uulkan , Uvaidillaeva Feruzakhan , Tagaeva Bermet , Sultanalieva Roza , Eftekhari Pierre
Published: February 2024

The knowledge about the features of energy metabolism in MAFLD in the population
living at different climatic and geographic heights is lacking. The goal of this
study is to explore the biochemical parameters of blood and erythrocyte energy
consumption in patients with MAFLD with and without DM2 living in the low- and
moderate-altitude regions of Central Asia. Our study was carried out on patients
living in low-altitude mountains: Bishkek, altitude=750–800 m; n=67 (MAFLD with
DM 2: n=24; MAFLD without DM2: n=25; control: n=18), and At-Bashy District,
Naryn Region, altitude=2046–2300 m; n=58 (MAFLD with DM2: n=28; MAFLD without
DM2: n=18; control: n=12). Non-alcoholic fatty liver disease was diagnosed
according to history, laboratory tests, liver ultrasound, and exclusion of other
liver diseases. The level of liver fibrosis was determined using the FIB-4
score. Blood adenosine 5′-triphosphate (ATP) was determined using the
CellTiter-Glo method. Healthy residents living in moderate altitudes have
significantly higher levels of cytosolic ATP in their blood (p+≤+0.05) than
residents living in low mountains. MAFLD is characterized by an increase in the
level of ATP concentration in their blood. ATP concentration decreased
significantly in patients with MAFLD with DM2 living in moderate-altitude in
comparison to those living in low-altitude mountains. The results suggest that
chronic altitude hypoxia leads to a breakdown in adaptive mechanisms of energy
metabolism of ATP in patients with MAFLD with type 2 DM.
Age-Related Quality of Life in Cardiac Surgical Patients with Extracorporeal Life Support
Authors: Terrazas Jesús A. , Stadlbauer Andrea C. , Li Jing , Bitzinger Diane , Diez Claudius , Schmid Christof , Camboni Daniele
Published: February 2024

Background The rationale of the study was to analyze the impact of age on quality of life (QoL) in patients who had undergone cardiac surgery with consecutive extracorporeal life support (ECLS) treatment.

Methods The study population consisted of 200 patients, operated upon between August 2006 and December 2018. The patient cohort was divided into two groups following an arbitrary cutoff age of 70 years. Comparative outcome analysis was calculated utilizing the European Quality of Life-5-Dimensions-5-Level Version (EQ-5D-5L).

Results A total of 113 patients were 70 years or less old (group young), whereas 87 patients were older than 70 years (group old). In 45.7% of cases, the ECLS system was established during cardiogenic shock and external cardiac massage. The overall survival-to-discharge was 31.5% (n = 63), with a significantly better survival in the younger patient group (young = 38.9%; old = 21.8%, p = 0.01). Forty-two patients (66%) responded to the QoL survey after a median follow-up of 4.3 years. Older patients reported more problems with mobility (y = 52%; o = 88%, p = 0.02) and self-care (y = 24%; o = 76%, p = 0.01). However, the patients' self-rated health status utilizing the Visual Analogue Scale revealed no differences (y = 70% [50–80%]; o = 70% [60–80%], p = 0.38). Likewise, the comparison with an age-adjusted German reference population revealed similar QoL indices. There were no statistically significant differences in the EQ-5D-5L index values related to sex, number of comorbidities, and emergency procedures.

Conclusion Despite the limited sample size due to the high mortality rate especially in elderly, the present study suggests that QoL of elderly patients surviving ECLS treatment is almost comparable to younger patients.
Vertical tumor-positive resection margins and the risk of residual neoplasia after endoscopic resection of Barrett’s neoplasia: a nationwide cohort with pathology reassessment
Authors: van Tilburg Laurelle , Verheij Eva P. D. , van de Ven Steffi E. M. , van Munster Sanne N. , Weusten Bas L. A. M. , Herrero Lorenza Alvarez , Nagengast Wouter B. , Schoon Erik J. , Alkhalaf Alaa , Bergman Jacques J. G. H. M. , Pouw Roos E. , Oudijk Lindsey , Meijer Sybren L. , Jansen Marnix , Doukas Michail , Koch Arjun D. ,   on behalf of the Dutch Barrett Expert Centers and the Dutch Barrett Expert Centers Study Group
Published: February 2024

Background This study evaluated the proportion of patients with residual neoplasia after endoscopic resection (ER) for Barrett’s neoplasia with confirmed tumor-positive vertical resection margin (R1v).

Methods This retrospective cohort study included patients undergoing ER for Barrett’s neoplasia with histologically documented R1v since 2008 in the Dutch Barrett Expert Centers. We defined R1v as cancer cells touching vertical resection margins and Rx as nonassessable margins. Reassessment of R1v specimens was performed by experienced pathologists until consensus was reached regarding vertical margins.

Results 101/110 included patients had macroscopically complete resections (17 T1a, 84 T1b), and 99/101 (98%) ER specimens were histologically reassessed, with R1v confirmed in 74 patients (75%), Rx in 16%, and R0 in 9%. Presence/absence of residual neoplasia could be assessed in 66/74 patients during endoscopic reassessment (52) and/or in the surgical resection specimen (14), and 33/66 (50%) had residual neoplasia. Residual neoplasia detected during endoscopy was always endoscopically visible and biopsies from a normal-appearing ER scar did not detect additional neoplasia. Of 25 patients who underwent endoscopic follow-up (median 37 months [interquartile range 12–50]), 4 developed local recurrence (16.0%), all detected as visible abnormalities.

Conclusions After ER with R1v, 50% of patients had no residual neoplasia. Histological evaluation of ER margins appears challenging, as in this study 75% of documented R1v cases were confirmed during reassessment. Endoscopic reassessment 8–12 weeks after ER seems to accurately detect residual neoplasia and can help to determine the most appropriate strategy for patients with R1v.
Divergent Reactivity of δ-Acetoxy Allenoates with 1,3-Bisnucleo­philes: Synthesis of Multisubstituted Pyran, Dihydropyran, and 3-Vinylpent-2-enedioate Scaffolds
Authors: Swamy K. C. Kumara , Khan Shabbir Ahmed
Published: February 2024

Base-dependent synthesis of tetrasubstituted pyrans or 3,4-dihydropyrans using δ-acetoxy allenoates and enolizable carbonyls like cyclohexan-1,3-dione and ethyl benzoylacetate is reported. Thus, the use of DMAP as an organocatalytic base gives tetrasubstituted pyrans while DBU affords isomeric tetrasubstituted 3,4-dihydropyrans. The reaction of δ-acetoxy allenoates with ethyl benzoylacetate mediated by KO
t
Bu furnishes diethyl 3-vinylpent-2-enedioates.
The Impact of Sleep: From Ancient Rituals to Modern Challenges
Authors: Andersen Monica L. , Pires Gabriel Natan , Tufik Sergio
Published: February 2024

Although sleep is crucial for mental and physical health, insufficient sleep is a growing problem in our modern society. In general, adults need approximately eight hours of sleep per night, but this is often unfeasible nowadays. This sleep restriction has been observed, and it has worsened, throughout the past two centuries; therefore, it is more attributed to socioeconomic changes than to biological adaptations. The most important factors to contribute to this sleep restriction were the popularization of artificial light and industrialization. The present manuscript briefly overviews, from a socioanthropological perspective, the reasons why sleep has been impacted, disclosing its effects on individuals and on society.
Source of Pseudomonas Aeruginosa in Burn Wound
Authors: Keswani R. K. , Hooda R. S. , Behl S. N. , Naryana G. L. , Chugh T. D.
Published: February 2024

1. Ps. aerug. is the commonest causative organism of burn wound sepsis. In our patients i. e. 23 out of 35 patients it was present either alone or in combination.

2. Out of 23 patients infected with Ps. aerug., 11 were acquired in the hospital.

3. Of the 9 cases, who were sterile at the time of admission, 8 got pseudomonas during their stay in the hospital.

4. About one third uninfected individuals have been found to be faecal carriers of Pseudomonas during their hospital stay. They can conveniently be a source of wound infection, more so in the lower half of body. This has been convincingly seen in two cases by the use of epidemiological marker i. e. aeruginocine typing.

5. Our 3 patients became skin carriers during their stay in the hospital possibly because of various sources in the hospital.

6. Of 25 fomites in the hospital studied repeatedly during 12 weeks, 9 were shown to have pseudomonas aeruginosa which could be a source of cross infection.

7. 4%, dettol solution used in the hospital wards was found to be infected with Ps. aerug.in 4 of the 12 samples examined. This could be due to the use of same unsterilized container over and over again.
Testis in Postvasectomy Case – A Clinico-Pathological Study of 50 Cases
Authors: Bastian Prabha , Varghese Sara , Thomas P. A. , Nair Ramakrishnan K.
Published: February 2024

Vas deferens anastomosis was carried out in 50 cases. The different histological findings noted are normal histology, sloughing and disorganisation with active spermatogenesis, hypospermatogenesis, Leydig cell hyperplasia, focal atrophy of tubules, peritubuler thickening. extravasation of spermatozoa spermatogenic maturation arrest and sertoli cell only pattern (Table II). Surgical success was 94.8%, and pregnancy rate, 63.2%. The high percentage of successful reanastomosis of vas is likely to enhance the acceptibility of vasectomy as a method for family limitation and population control. Hcwever the relatively fow pregnancy rate in spite of high surgical success requires further investigation.
Pneumatization of Mastoid Air Cell System in Cleft Lip and Plate Cases
Authors: Bhatnagar S. K. , Gupta I. J. , Sharma R. N.
Published: February 2024

27 cases of cleft cases have undertaken in this study. Pneumatization of the mastoid air cell system has been studied in a case of cleft lip & palate. The area of pneumatization is less in cleft lip and palate populations as compared Lo control subject.
Experience With Groin Flap in the Management of Hand Injuries
Authors: Bhattacharya Dr. V. , Sinha Dr. J. K. , Tripathi Dr. F. M.
Published: February 2024

Our exprience of resurfacing hand injuries of various types requiring full thickness cover, in a series of 20 cases, with groin flap is presented. Age incidence and local causative factors are analysed. The anatomical consideration of this versatile Hlap has been discussed in brief. Predominantly the right hand of the young male members are involed. Injury to dorsal and dorsovolar surfaces were of common experience of occurence. Ipsilateral groin flap were used in seventeen cases, contrilateral flap in two cases and in one case bilateral groin flaps were given simultaneously, Flaps ol various dimensions were used. The complications encountered were few and not of serious nature. The donor area was covered by split skin graft except in small size flaps where it was sutured directly. The average duration of hospital stay was 33 days. The various advintages of this flap have been discussed. We recommend this as an ideal flap in covering injured hands requiring full thickness skin cover.
Flaps on the Limbs
Authors: Chowdhury Dr. Mrs. Siti Roy
Published: February 2024

Used for resurfacing defects of upper and lower limb have been discussed. Role of bridge flap to resurface fairly sizeable wound of the hand are discussed, also role of gastronaemius myocutaneus flap in resurfacing lower limb has been discussed in detail.
Use of Post Nasal Inlay in Leprosy
Authors: Dr Govila A.
Published: February 2024

The purpose of this paper is to present a hypothesis about the mechanism of causation of nasal deformity in leprosy, based on observations on 20 cases of nasal collapse. According to this observation the earliest site of maximum destruction and replacement fibrosis is the central point of the junction of the nasal bones and the upper nasal lateral cartilages (Referred as central core). From this point to a point on the most anterior part of the junction of the perpendicular plate of the ethmoid to the vomer. A fibrous remification forms at the posterior margin of the septal perforation. Contracture of this remification causes saddle deformity of the nose. Precise steps of the technique are definzd and the complications arising from the faulty technique and their treatment is presented. A devise for the prevention of graft contraction is presented.
Male Pseudohermaphrodite With Uterus In Scrotum
Authors: Sahai Dr. Yadava Vishwa Nath , Prakash Dr. Dubey Surya , Kumar Dr. Saxena Santosh
Published: February 2024

An unusual case of a male pseudohermaphrodite where uterus with its fallopian tubes and both the testes with their vas deference were present on one side only, has been presented. The gonadal abnormality was found to be associated with oblique inguinal hernia on the same side.
“BURNS CAUSED BY ELECTRICITY”. (A Review of one hundred cases)
Authors: Verma Prof. P. K. , Verma Dr. S. K.
Published: February 2024

Hundred cases of electrical burn have been studied. Young males adults were found to be more affected and the percentage of burn in most of the cases were rather low. High tension injury was the cause in majority of the cases. The upper extremity was involved in 80%, of cases. Cataract in the eye developed in 8 percent of the cases in which the injury was in the region of the scalp. In the region of the hand to restore function an early excision was the treatment of choice. Cases requiring amputation were delayed till a line of demarcation developed. The region of scalp was treated conservatively. As electrical injury simulates crush injury proper and adequate intravenous fluid were administered irrespective of their low percentage of burn.
Role Of Tubed Pedicle From Thigh For Resurfacing Defects Of Lower Extremity
Authors: Singh Li Col Ajaipal , Kathpalia Col P. M. L.
Published: February 2024

The utility and versatility of a tubed pedicle from the thigh hither-to unexploited for resurfacing difficult and extensive cutaneous defects of the lower extremity have been discussed. The experiences in a series of 13 patients have been presented. We advocate this method in all major defects where indications exist for importing tissues froa a distance (abdominal tubed pedicle or tubed groin flap) for reasons of convenience and ease of fixation. The donor site is well covered and leaves no residual disability.
UDCA for Drug-Induced Liver Disease: Clinical and Pathophysiological Basis
Authors: Bessone Fernando , Hillotte Geraldine L. , Ahumada Natalia , Jaureguizahar Fernanda , Medeot Anabela C. , Roma Marcelo G.
Published: February 2024

Drug-induced liver injury (DILI) is an adverse reaction to medications and other xenobiotics that leads to liver dysfunction. Based on differential clinical patterns of injury, DILI is classified into hepatocellular, cholestatic, and mixed types; although hepatocellular DILI is associated with inflammation, necrosis, and apoptosis, cholestatic DILI is associated with bile plugs and bile duct paucity. Ursodeoxycholic acid (UDCA) has been empirically used as a supportive drug mainly in cholestatic DILI, but both curative and prophylactic beneficial effects have been observed for hepatocellular DILI as well, according to preliminary clinical studies. This could reflect the fact that UDCA has a plethora of beneficial effects potentially useful to treat the wide range of injuries with different etiologies and pathomechanisms occurring in both types of DILI, including anticholestatic, antioxidant, anti-inflammatory, antiapoptotic, antinecrotic, mitoprotective, endoplasmic reticulum stress alleviating, and immunomodulatory properties. In this review, a revision of the literature has been performed to evaluate the efficacy of UDCA across the whole DILI spectrum, and these findings were associated with the multiple mechanisms of UDCA hepatoprotection. This should help better rationalize and systematize the use of this versatile and safe hepatoprotector in each type of DILI scenarios.
Development of a Coagulation Disorders Unit
Authors: Szanto Timea , Helin Tuukka , Joutsi-Korhonen Lotta , Lehtinen Anna-Elina , El Beayni Nancy , Lepäntalo Aino , Lassila Riitta
Published: February 2024

Our Coagulation Disorders Unit in Helsinki, Finland, provides 24/7 services for local and national hospitals and colleagues upon requests regarding bleeding and thrombosis diagnostics and management, including follow-up. The unit has a tight connection between the clinic and laboratory, and its maintenance and sharing knowledge and observations have been priorities, already for over 20 years and will continue to be of major importance. The consultation service is provided by phone during daytime and on-call hours, and in written form sent electronically to the consulting stakeholders. Thrombosis and hemostasis-targeted outpatient clinics are also available for the patients referred to the center. Writing local guidance and official guidelines, Nordic, European and international collaboration, and educational activities including social communication are critical elements for the Coagulation Disorders Unit. Alertness to acute coagulation abnormalities, such as occurred during COVID-19 and vaccine-induced thrombosis and thrombocytopenia, and development of strategies to manage cross-disciplinary problems are topics which call upon broad networking. The Nordic community has an ongoing historical meeting, which has been circulating among coagulation centers for the past 56 years. At the European level, the European Association of Haemophilia and Allied Disorders focuses on bleeding disorders and their management, including safety surveillance. The International Society of Thrombosis and Haemostasis offers excellent basic and clinical benchmarks for any Coagulation Disorders Unit. We hope that the description of the development and implementation of our Coagulation Disorders Unit in Helsinki achieves international interest and broadens international collaboration. Finally, we congratulate STH on its great contributions around the globe and for providing a vivid forum to foster the discipline of thrombosis and hemostasis.
Variability in Practice and Implementation of Oxygen Target Saturation Policies in United States' Neonatal Intensive Care Units
Authors: Parikh Pratik , White Robert D. , Tolia Veeral N. , Reyburn Brent , Guillory Charleta , Ahmad Kaashif A.
Published: February 2024

Objective This study aimed to describe target oxygen saturation (SpO2) ranges used for premature infants in United States' neonatal intensive care units (NICUs) and to describe if these target SpO2 ranges have changed in recent years.

Study Design A 29-question survey focused on target SpO2 practices and policies was distributed via the NICU medical directors listservs for the American Academy of Pediatrics Section of Neonatal-Perinatal Medicine and Pediatrix Medical Group between August and October of 2021. Results were collected via Research Electronic Data Capture (REDCap).

Results We received responses representing 170 unique, levels 2, 3, and 4 NICUs from 36 states. Most NICUs (130, 78%) have recently changed their SpO2 targets in response to target SpO2 clinical trials. Over time, the most commonly reported target SpO2 range has shifted from 88–92% to 90–95. Of NICUs that changed limits, the most common lower SpO2 limits increased from 88 to 90% and the upper SpO2 limits changed from 92 to 95%. The interquartile range for lower SpO2 limit shifted from 85–88% to 88–90% and the IQR for upper SpO2 limit decreased from 92–95 to 94–95%. Most NICUs had designated conditions that would allow for deviations from standard target SpO2 ranges. These most commonly include pulmonary hypertension (152, 95%), severe bronchopulmonary dysplasia (81, 51%), and retinopathy of prematurity (51, 32%).

Conclusion Oxygen saturation limits have changed over time with an overall increase in targeted SpO2. However, there remains considerable interunit variation in SpO2 policies. There is a need to achieve consensus to optimize clinical outcomes.

Key Points
Network Risk Parity: graph theory-based portfolio construction
Authors: Ciciretti Vito , Pallotta Alberto
Published: February 2024

This study presents network risk parity, a graph theory-based portfolio construction methodology that arises from a thoughtful critique of the clustering-based approach used by hierarchical risk parity. Advantages of network risk parity include: the ability to capture one-to-many relationships between securities, overcoming the one-to-one limitation; the capacity to leverage the mathematics of graph theory, which enables us, among other things, to demonstrate that the resulting portfolios is less concentrated than those obtained with mean-variance; and the ability to simplify the model specification by eliminating the dependency on the selection of a distance and linkage function. Performance-wise, due to a better representation of systematic risk within the minimum spanning tree, network risk parity outperforms hierarchical risk parity and other competing methods, especially as the number of portfolio constituents increases.
Research on accurate pipetting complementation model for high-throughput molecular detection platform
Authors: Zhang Haotian , He Xinyi , Wang Shaochen , Wu Fengxue , Zhi Yinjie , Li Yanfeng , Wang Xiaonan , Ma Yuxuan , Meng Fan , Wang Chao
Published: February 2024

The incidence of infectious diseases has risen in recent years, leading to a significant surge in the demand for medical molecular detection. High-throughput molecular detection platforms play a crucial role in facilitating rapid and efficient molecular detection. Among the various techniques employed in high-throughput molecular detection, microliquid transfer stands out as one of the most frequently utilized methods. However, ensuring the accuracy of liquid transfer poses a challenge due to variations in the physical and chemical properties of different samples and reagents. In this study, a pipetting complementation model was developed specifically for the serum, paraffin oil, and throat swabs. The aim was to enhance the transfer accuracy of diverse liquids in the context of high-throughput molecular detection, ultimately ensuring detection reliability and stability. The experimental findings revealed notable improvements in pipetting accuracy after compensating for the three liquids. In particular, the pipetting error rates decreased by 52.5, 96, and 71.4% for serum, paraffin oil, and throat swabs, respectively. These results underscore the model’s effectiveness in providing reliable support for the precise transfer of liquids on the high-throughput molecular detection platform.
A method for rheological measurements of air sensitive samples
Authors: Russell Ben A. , Wynne Klaas
Published: February 2024

The rheology of air or moisture sensitive liquids, gels, and glasses requires complicated rheometer-in-glovebox laboratory setups. Here, we demonstrate the use of a heavier-than-air cover gas, sulfur hexafluoride, and the design of a cover gas container that can attach to the lower geometry plate of any rheometer to carry out rheology experiments on air-sensitive liquids and soft solids. Rheological measurements of air-reactive ionic liquid trimethylsulfonium bromide–AlCl3, moisture sensitive titanium(IV) propoxide, and glycerin demonstrate the effectiveness of the cover-gas method for loading samples on acquiring correct temperature dependent viscosity data of the sample in the absence of reaction products.
High figure-of-merit of single-walled carbon nanotubes films with metallic type conduction
Authors: Mishra Suman K. , Kaushal Amit , Alexander Rajath , Patra Soumyabrata , Bharti Meetu , Rawat V. S. , Muthe K. P. , Singh Bhanu Pratap , Singh Ajay
Published: February 2024

Carbon nanotubes are promising candidates for thermoelectric power generation because of their one-dimensionality mediated high Seebeck coefficient, high electrical conductivity with added advantages of flexibility, light weight, and scalability. We report the temperature-dependent thermoelectric properties of single-walled carbon nanotube (SWCNTs) films. The SWCNTs films exhibit p-type metallic conduction with high Seebeck coefficient (∼69.5 μVK−1) and moderate electrical conductivity (∼76 Scm−1). The films exhibit low thermal conductivity (∼0.1 Wm−1 K−1) due to phonon scattering at the interjunction region. The synergetic combination of thermoelectric properties resulted in a high figure-of-merit of ∼0.11 at 305 K. A flexible thermoelectric generator based on SWCNTs films mounted on a curved hot surface exhibited an output of 17 mV and 54 μA under a small temperature gradient of 10 K. The present work provides possible avenues for developing wearable SWCNTs based thermoelectric power generation modules for harvesting body heat.
Dynamic property of a stochastic cooperative species system with distributed delays and Ornstein–Uhlenbeck process
Authors: Zhou Yaxin , Jiang Daqing
Published: February 2024

Scanning the whole writing, we discuss a stochastic cooperative species system with distributed delays under the influences of Ornstein–Uhlenbeck process of mean regression. We successfully obtain the existence and uniqueness of positive solutions for stochastic system at first. Secondly, by studying the Lyapunov function, we present the existence of the stationary distribution of the system. We are relatively familiar with the understanding of the density function of random systems. This paper also gives the expression of the density function of the random system near the unique positive equilibrium. In addition, the asymptotic properties of the p-moment boundedness and solution of the stochastic population system are also studied. In particular, we use numerical simulation to verify the theoretical results in the last section.
On the transport behavior of shale gas in nanochannels with fractal roughness
Authors: Lou Liqun , Chen Peijian , Peng Juan , Zhu Jiaming , Liu Guannan
Published: February 2024

As an efficient and environmentally friendly source of energy, shale gas is abundantly available and continues to contribute to the economy growth because of its huge potential for production. However, accurately predicting the transport behavior of shale gas is still challenging due to the small scale and complexity of nanochannels, which impedes the efficiency of recovery. In this paper, the transport behavior of shale gas in nanochannels with fractal roughness is studied by molecular dynamics simulation and theoretical analysis. It is found that the present work functions well to predict the transport behavior of shale gas in nanochannels with roughness. The introduction of fractal roughness hinders the transport of shale gas and leads to a complex trajectory of methane molecules in nanochannels. Furthermore, it is interesting to find the average gas viscosity increases, while the gas flux decreases with the increase in the inclined angle due to the impediment effect after the deflection. These results are helpful for understanding the migration of shale gas in nanochannels with roughness and guiding the improvement of shale gas recovery in practical applications.
Thermoelastic modeling of cubic lattices from granular materials to atomic crystals
Authors: Kim Byung-Wook , Liu Chao , Yin Huiming
Published: February 2024

When a cubic lattice is confined by a surface layer, the effective thermoelastic properties can be tailored by the prestress produced by the surface. The thermal expansion coefficient, temperature derivative of elasticity, and the equation of state (EOS) of the solid depend on the potential of each bond and the lattice structure, which can be predicted by the recently developed singum model. This paper first uses a granular lattice confined by a spherical shell to demonstrate singum modeling of the thermoelastic behavior of the cubic lattices and then extends it to atomic crystal lattices by considering the surface tension and long-range interactions. Given the elasticity and the EOS of a cubic crystal, the interatomic potential can be inversely derived. As the bond length changes with thermal expansion and pressure, the singum model predicts the temperature- and pressure-dependent elasticity. Using the orientational average, isotropic elastic constants can be obtained for polycrystals. The case study of copper (Cu) demonstrates the versatility of the model for different cubic lattices and predicts the experimental results of pressure- and temperature-dependent elasticity. The singum model is general for different lattice types and EOS forms and provides clear physical and mechanical meanings to correlate the interatomic potential, EOS, and elasticity in the closed-form formulation, which is very useful in engineering design and analysis of metal structural members in fire, geothermal, and space applications without the needs of large-scale numerical simulations.
Simulations and models for the Richtmyer–Meshkov instability with broadband perturbations
Authors: Dimonte Guy , Nagori Madhav , Ramaprabhu Praveen , Boureima Ismael
Published: February 2024

The Richtmyer–Meshkov instability (RMI) is shock driven and affects many phenomena from inertial fusion to supernova explosions. The behavior of single-modes in the RMI has been studied extensively but less is known with the broadband perturbations that occur in applications. Here, we describe extensive numerical simulations and modeling of the RMI with broadband perturbations with an initial power spectrum of the form P ∝ km, where k is the wavenumber. The hydrodynamic condition is the same as in the θ-Group Collaboration [Thornber et al., “Late-time growth rate, mixing, and anisotropy in the multimode narrowband Richtmyer–Meshkov instability: The θ-group collaboration,” Phys. Fluids 29, 105107 (2017)] with a Mach ∼1.86 shock and gamma-law = 5/3 fluids with Atwood number A = −0.5. The bubble amplitude hB is found to grow in two stages. Initially, hB undergoes a phase-inversion and grows linearly in time (t) at a rate consistent with a linear theory. Asymptotically, hB grows as a power law ∼tθ when k|hB| > O(1), where k is the average wavenumber for the initial spectrum. The RMI behavior in simulations and modeling agree over a wide range of exponent m, spectral width, initial amplitude, and time. The agreement is quantified objectively using statistical analysis.
Boosting the responsivity of amorphous-Ga2O3 solar-blind photodetector via organosilicon surface passivation
Authors: Liu Yiming , Qin Houyun , Peng Chong , Guo Jiarui , Chang Yiyang , Liu Kaiyuan , Zhao Yi
Published: February 2024

In this paper, an amorphous Ga2O3 metal–semiconductor–metal photodetectors passivated by the organosilicon layer were reported. Due to the excellent passivation property of the passivation layer and the diffusion effect of hydrogen, the responsivity of Ga2O3 photodetectors was improved effectively, while the dark state current is basically unchanged. The results of x-ray photoelectron spectroscopy have proved that the amount of oxygen vacancy near the interface between organosilicon and Ga2O3 layer has been passivated and the surface chemisorption was suppressed via capping a foreign layer after the deposition of organosilicon passivation layer. The Ga2O3 photodetectors with organosilicon passivation layer exhibit a boosted performance, with a low dark current of 2.96 × 10−12 A, a responsivity of 11.82 A/W, and a specific detectivity of 9.01 × 1014 Jones.
Solvation enhanced long-range proton transfer in aqueous phase for glycolaldehyde hydrogenation over Ru/C catalyst
Authors: Qiao Ying , Cao Wei , Qian Sheng-Jie , Yao Zhen , Wang Yang-Gang
Published: February 2024

The catalytic hydrogenation of biomass-derived chemicals is essential in chemical industry due to the growing demand for sustainable and renewable energy sources. In this study, we present a comprehensive theoretical investigation regarding the hydrogenation of glycolaldehyde to ethylene glycol over a Ru/C catalyst by employing density functional theory and ab initio molecular dynamics simulations. With inclusion of explicit solvation, we have demonstrated that the glycolaldehyde hydrogenation is significantly improved due to the fast proton transfer through the hydrogen bond network. The enhanced activity could be attributed to the participation of the solvent water as the hydrogen source and the highly positively charged state of a Ru cluster in an aqueous phase, which are critical for the activation of aldehyde groups and proton-assisted hydrogenation. Overall, our findings provide valuable insights into glycolaldehyde hydrogenation over Ru/C catalysts in the aqueous phase, highlighting the importance of solvation effects in the biomass conversion.
Highly tailorable thermomechanical properties of nanograined silicon: Importance of grain size and grain anisotropy
Authors: Cao Jiahui , Wang Han , Ferrer-Argemi Laia , Cao Penghui , Lee Jaeho
Published: February 2024

Nanocrystalline silicon can have unique thermal transport and mechanical properties governed by its constituent grain microstructure. Here, we use phonon ray-tracing and molecular dynamics simulations to demonstrate the largely tunable thermomechanical behaviors with varying grain sizes (a0) and aspect ratios (ξ). Our work shows that, by selectively increasing the grain size along the heat transfer direction while keeping the grain area constant, the in-plane lattice thermal conductivity (kx) increases more significantly than the cross-plane lattice thermal conductivity (ky) due to anisotropic phonon–grain boundary scattering. While kx generally increases with increasing ξ, a critical value exists for ξ at which kx reaches its maximum. Beyond this transition point, further increases in ξ result in a decrease in kx due to substantial scattering of low-frequency phonons with anisotropic grain boundaries. Moreover, we observe reductions in the elastic and shear modulus with decreasing grain size, and this lattice softening leads to significant reductions in phonon group velocity and thermal conductivity. By considering both thermal and mechanical size effects, we identify two distinct regimes of thermal transport, in which anisotropic phonon–grain boundary scattering becomes more appreciable at low temperatures and lattice softening becomes more pronounced at high temperatures. Through phonon spectral analysis, we attribute the significant thermal conductivity anisotropy in nanograined silicon to grain boundary scattering of low-frequency phonons and the softening-driven thermal conductivity reduction to Umklapp scattering of high-frequency phonons. These findings offer insights into the manipulation of thermomechanical properties of nanocrystalline silicon via microstructure engineering, carrying profound implications for the development of future nanomaterials.
Impact of sandpaper grit size on drag reduction and plastron stability of super-hydrophobic surface in turbulent flows
Authors: Mohammadshahi Shabnam , O'Coin Daniel , Ling Hangjian
Published: February 2024

In this work, we experimentally investigated the impact of surface roughness on drag reduction as well as the plastron stability of superhydrophobic surfaces (SHSs) in turbulent flows. A series of SHSs were fabricated by spraying hydrophobic nanoparticles on sandpapers. By changing the grit size of sandpapers from 240 to 1500, the root mean square roughness height (krms) of the SHSs varied from 4 to 14 μm. The experiments were performed in a turbulent channel flow facility, where the mean flow speed (Um) varied from 0.5 to 4.4 m/s, and the Reynolds number (Rem) based on Um and channel height changed from 3400 to 26 400. The drag reduction by SHSs was measured based on pressure drops in the fully developed flow region. The plastron status and gas fraction (φg) were simultaneously monitored by reflected-light microscopy. Our results showed a strong correlation between drag reduction and krms+ = krms/δv, where δv is the viscous length scale. For krms+ < 1, drag reduction was independent of krms+. A maximum 47% drag reduction was observed. For 1 < krms+ < 2, less drag reduction was observed due to the roughness effect. And for krms+ > 2, the SHSs caused an increase in drag. Furthermore, we found that surface roughness influenced the trend of plastron depletion in turbulent flows. As increasing Rem, φg reduced gradually for SHSs with large krms, but reduced rapidly and maintained as a constant for SHSs with small krms. Finally, we found that as increasing Rem, the slip length of SHS reduced, although φg was nearly a constant.
Study on the self-adaptive process of droplet traffic to a perturbation of flow resistance at the arms of a micro-T-junction
Authors: He Kui , Zhang Liangzhen , Yuan Wuzhi , Li Zhiyong , Yang Min-Lin , Yang Yu , Huang Si-Min
Published: February 2024

The response of the water–oil droplet flow to a perturbation of flow resistance added at the arms of a bypassed micro-T-junction is studied through a numerical method. The capillary number of the continuous flow varies between 0.007 and 0.034. Once an additional flow resistance is introduced at the arms of the T-junction, the flow self-adapts to the perturbation and droplets show complex dynamics at the junction, including splitting, merging, and reshaping. During the self-adaptive process, the instantaneous splitting ratios of the dispersed flow show positive correlations with that of the continuous flow. The correlation coefficient reduces as the increase in the amplitude of the perturbation. The ensemble splitting ratios of them, however, are independent. It shows a rather simple law that the ensemble splitting ratios of oil anchor at around a constant value while the corresponding parameter of water varies from 0 to 1. It illustrates that the droplet flow splitting at a T-junction resembles a resilient system, the stiffness of which depends on the capillary number of the flow. The energy loss of the system induced by a perturbation of the flow resistance is self-reduced by just redistributing of droplets into the two arms.
Iterative learning control for differential inclusion systems with random fading channels by varying average technique
Authors: Qiu Wanzheng , Wang JinRong , Shen Dong
Published: February 2024

The aim of this paper is to study iterative learning control for differential inclusion systems with random fading channels between the plant and the controller. In reality, the phenomenon of fading will inevitably occur in network transmission, which will greatly affect the tracking ability of output trajectory. This study discusses the impact of fading channel on tracking performance at the input and output sides, respectively. First, a set-valued mapping in a differential inclusion system with uncertainty is converted into a single-valued mapping by means of a Steiner-type selector. Then, to offset the effect of the fading channel and improve the tracking ability, a variable local average operator is constructed. The convergence of the learning control algorithm designed by the average operator is proved. The results show that the parameters in the varying local average operator can be adjusted to trade-off between the learning rate and the fading offset rate. Finally, the theoretical results are verified by numerical simulation of the switched reluctance motors.
Primary resonance characteristics of a cylindrical bubble based on the multi-scale method
Authors: Wang Xiaoyu , Zhang Xiangqing , Li Shaowei , Zhang Cheng , Zhang Yuning , Jiang Qiongqiong , Li Jingtao , Zheng Shu , Zhang Yuning
Published: February 2024

This paper describes a primary resonance theoretical model for a cylindrical bubble under acoustic excitation. Based on the multi-scale method, an analytical solution of the bubble–wall equation with second-order accuracy is obtained and numerically verified. The oscillation characteristics in the time domain and the frequency response characteristics of the oscillations under primary resonance are analyzed with different amplitudes and frequencies of acoustic excitation and the equilibrium radius of the bubble. This study yields the following primary findings: (1) For the cylindrical bubbles, the primary resonance of the bubble exists in unstable regions. Nonlinear behaviors such as jumps, hysteresis, and multivalued solutions may be widely present. (2) As the amplitude of the acoustic excitation and the bubble equilibrium radius increase, the backbone of the amplitude–frequency response curve bends to the left and the unstable region gradually expands. (3) When the dimensionless amplitude of the acoustic excitation is less than 0.005 and the bubble equilibrium radius is less than 1.0 × 10−5 m, the unstable region of resonance disappears.
Characterization of the mixing layer self-similarity with multiple parameters
Authors: Abuhegazy Mohamed , Poroseva Svetlana V. , Colmenares F. Juan D. , Murman Scott M.
Published: February 2024

In the paper, results from direct numerical simulation of a planar incompressible mixing layer spatially developing incompressible between two co-flowing laminar boundary layers are used to analyze a possibility for multiple flow parameters to achieve self-similarity within the same flow region. The Reynolds numbers for the boundary layers are 3930 and 2412 based on the free-stream velocities far above and below the splitter plate and the boundary layer thicknesses at the splitter plate trailing edge. The three-dimensional computational domain is sufficiently large for the mixing layer transition to fully turbulent far upstream the domain exit. The mixing layer growth is characterized using various definitions of the mixing layer thickness. It is shown that the proposed mixing layer thickness based on the gradient of the streamwise mean velocity in the transverse direction defines more accurately the area of turbulent mixing. Three regions of the flow linear growth are discovered using a rigorous approach, with only one of them being located within the fully turbulent mixing layer. Other parameters included in the flow self-similarity analysis are the streamwise and transverse mean velocities along with the Reynolds stresses. New normalization is proposed to observe self-similarity of the transverse mean velocity. The flow region where all considered parameters exhibit self-similarity is determined. It is shown that this region is limited by the “pulsating” streamwise distribution of the transverse mean velocity. The computational domain dimension along with the boundary conditions in the transverse direction for all considered parameters are suggested for the Reynolds-averaged Navier–Stokes simulations.
Theoretical analysis of dendrite formation generated in an electroosmotic flow with variable shape microelectrodes
Authors: Vargas Carlos , Méndez Federico , Docoslis Aristides , Escobedo Carlos
Published: February 2024

In this work, an analytical solution for the hydrodynamic forces that transport silver ions between microelectrodes of axially variable shape is presented. Four different microelectrode shapes were employed to explore the use of passive methods for silver dendritic growth. The results indicate that a fractal microelectrode shape promotes better silver dendritic formation due to lightning rod effect, while in all configurations, a condition of no-contact between dendrites is reached due to an induced pressure field.
Optimal control of N–H photodissociation of pyridinyl
Authors: Alamgir Mohammed , Mahapatra Susanta
Published: February 2024

The N–H photodissociation dynamics of the pyridinyl radical upon continuous excitation to the optically bright, first excited ππ* electronic state by an ultra-violet (UV) laser pulse has been investigated within the mathematical framework of optimal control theory. The genetic algorithm (GA) is employed as the optimization protocol. We considered a three-state and three-mode model Hamiltonian, which includes the reaction coordinate, R (a1 symmetry); the coupling coordinates (namely, out-of-plane bending coordinate of the hydrogen atom of azine group), Θ (b1 symmetry); and the wagging mode, Q9 (a2 symmetry). The three electronic states are the ground, ππ*, and πσ* states. The πσ* state crosses both the ground state and the ππ* state, and it is a repulsive state on which N–H dissociation occurs upon photoexcitation. Different vibrational wave functions along the coupling coordinates, Θ and Q9, of the ground electronic state are used as the initial condition for solving the time-dependent Schrödinger equation. The optimal UV laser pulse is designed by applying the GA, which maximizes the dissociation yield. We obtained over 95% dissociation yield through the πσ* asymptote using the optimal pulse of a time duration of ∼30 000 a.u. (∼725.66 fs).