bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of an Electronic Health Record-Based Intervention on Documentation Practices
Authors: Shah Shreya , Bedgood Michael , Devon-Sand Anna , Dolphin-Dempsey Cathriona , Cherukuri Venkata , Weng Kirsti , Lin Steven , Sharp Christopher
Published: July 2024

Background Documentation burden is one of the largest contributors to physician burnout. Evaluation and Management (E&M) coding changes were implemented in 2021 to alleviate documentation burden.

Objectives We used this opportunity to develop documentation best practices, implement new electronic health record (EHR) tools, and study the potential impact on provider experiences with documentation related to these 2021 E&M changes, documentation length, and time spent documenting at an academic medical center.

Methods Five actionable best practices, developed through a consensus-driven, multidisciplinary approach in November 2020, led to the creation of two new ambulatory note templates, one for E&M visits (implemented in January 2021) and another for preventative visits (implemented in May 2021). As part of a quality-improvement initiative at nine faculty primary care clinics, surveys were developed utilizing a 5-point Likert scale to assess provider perceptions and deidentified EHR metadata (Signal, Epic Systems) were analyzed to measure changes in EHR use metrics between a pre-E&M changes timeframe (August 2020–December 2020) and a post-E&M change timeframe (August 2021–December 2021). A subgroup analysis was conducted comparing EHR use metrics among note template utilizers versus nonutilizers. Any provider who used one of the note templates at least once was categorized as a utilizer.

Results Between January 2021 and December 2021, the adoption of the E&M visit template was 31,480 instances among 120 unique ambulatory providers, and adoption of the preventative visit template was 1,464 instances among 22 unique ambulatory providers. Survey response rate among faculty primary care providers was 82% (88/107): 55% (48/88) believed the 2021 E&M changes provided an opportunity to reduce documentation burden, and 28% reported favorable satisfaction with time spent documenting. Among providers who reported using one or both of the new note templates, 81% (35/43) of survey respondents reported favorable satisfaction with new note templates. EHR use metric analyses revealed a small, yet significant reduction in time in notes per appointment (p = 0.004) with no significant change in documentation length of notes (p = 0.45). Note template utilization was associated with a statistically significant reduction in documentation length (p = 0.034).

Conclusion This study shows modest progress in improving EHR use measures of documentation length and time spent documenting following the 2021 E&M changes, but without great improvement in perceived documentation burden. Additional tools are needed to reduce documentation burden and further research is needed to understand the impact of these interventions.
Role of Parameters in Whole Blood Analysis as in Indicator of
Systemic Inflammation in Children with Rheumatic Valve Diseases
Authors: Nurmammadova Lala , Yozgat Yilmaz , Yozgat Can Yilmaz , Babayeva Turkay , Bayramova Nigar , Talebazadeh Faraz , Koç Ertan , Kahraman Feyza Ustabas , Erenberk Ufuk
Published: July 2024

Purpose The most important cause of mortality and morbidity in acute
rheumatic fever (ARF) is carditis and rheumatic heart disease (RHD). The aim of
this study was to identify markers that may be indicators of chronic
inflammation in whole blood analyses in pediatric patients with RHD who
regularly received secondary deposilin prophylaxis.

Methods In our study, 100 children with ARF aged between 4 and 18 years
were followed up in the pediatric cardiology outpatient clinic of the patient
group. The control group consisted of 100 healthy children of the same sex and
age as the patient group. All children in the patient group regularly received
deposilin prophylaxis every 21 days. Our study included many whole blood
parameters that are reported in the literature to represent changes in chronic
inflammatory diseases. These parameters were CRP, RDW, PDW, MPV and leukocyte
subtypes, neutrophil, lymphocyte, monocyte counts and their ratios
(neutrophil/lymphocyte, platelet/lymphocyte and monocyte/lymphocyte).

Results Leukocyte count, lymphocyte count, basophil count, MLR and
basophil count were significantly lower in the patient group than in the control
group (p: 0.047, p: 0.023, p: 0.006). In addition, eosinophil count and RDW
value were significantly higher in the patient group than in the control group
(p: 0.043; p: 0.001).

Conclusion In our study, low leukocyte, lymphocyte, basophil, MLR and
higher eosinophil counts indicated that RDW could be effectively used as a
marker for regular depositilin prophylaxis in pediatric patients with RHD.
Articular Cartilage Damage in the Patellofemoral Compartment at ACL Reconstruction Predicts Poor Postoperative Subjective Outcomes in Patients Age 40 and Older
Authors: Miyamoto Ayato , Nakamae Atsuo , Tsukisaka Kazuhiro , Deie Masataka , Fujimoto Eisaku , Soda Yoshinori , Shimizu Ryo , Adachi Nobuo
Published: July 2024

The purpose of this study was to investigate factors that influence clinical outcomes after anterior cruciate ligament (ACL) reconstruction in patients aged ≥40 years. We studied 264 patients aged ≥40 and 154 patients aged ≤20 years who underwent ACL reconstruction at several surgical centers. A logistic regression analysis was conducted to identify factors that influenced the Knee Injury and Osteoarthritis Outcome Score (KOOS) at 1 year post-ACL reconstruction. In the older patient group, cartilage damage in the patellofemoral compartment at surgery was a significant risk factor for poor postoperative KOOS subscores (pain, activities of daily living [ADL], sports, and quality of life [QOL]). Articular cartilage damage in the lateral compartment also significantly influenced one of the postoperative KOOS subscores (symptoms). In the younger patient group, articular cartilage damage in any compartments did not influence the postoperative KOOS subscores; only two preoperative KOOS subscores (symptoms and QOL) significantly influenced their postoperative KOOS subscores. We concluded that the articular cartilage damage in the patellofemoral compartment at ACL reconstruction predicts poor KOOS subscores at the 1-year follow-up in patients aged ≥40 years.

Study Design Cohort study (Prevalence); Level of evidence, 2.
Comparison of the Cost-Effectiveness and Safety between Staged Bilateral Total Knee Arthroplasty and Simultaneous Bilateral Total Knee Arthroplasty: A Retrospective Cohort Study between 2001 and 2022
Authors: Tsui Omar W.K. , Chan Ping-Keung , Cheung Amy , Chan Vincent W.K. , Luk Michelle H. , Cheung Man-Hong , Lau Lawrence C.M. , Leung Thomas K.C. , Fu Henry , Chiu Kwong-Yuen
Published: July 2024

A substantial proportion of Hong Kong's aging population suffers from osteoarthritis in both knees. Bilateral total knee arthroplasty (BTKA) is a surgical option for addressing this condition and can be performed via two approaches: simultaneous BTKA (SimBTKA) and staged BTKA (StaBTKA). We compared the cost-effectiveness and safety of these two methods in our institution. We retrospectively reviewed 2,372 patients (SimBTKA, 772; StaBTKA, 1,600; females, 1,780; males, 592; mean age at SimBTKA, 70.4 ± 7.99 years; mean age at StaBTKA, 66.4 ± 7.50 years; p < 0.001) who underwent BTKA in our institution from 2001 to 2022. Patients were categorized according to the surgical approach. Patients undergoing BTKA in our institution were included. Particularly for SimBTKA, patients were assessed by anesthetists to be medically fit before undergoing the procedure according to their age, American Society of Anesthesiologists status, and osteoarthritis severity. The primary outcome was the length of stay (LOS) after surgery. The secondary outcomes were the 30-day unintended readmission, intensive care unit (ICU) admission, and death. SimBTKA had a shorter mean total LOS (acute hospital + rehabilitation center; SimBTKA, 13.09 days; StaBTKA, 18.12 days; p < 0.001) and mean LOS in acute hospital (SimBTKA, 7.70 days; StaBTKA, 10.42 days; p < 0.001). However, no significant difference was found in the mean LOS in rehabilitation centers (SimBTKA, 5.47 days; StaBTKA, 6.32 days; p > 0.05) between the two approaches. The 30-day unintended readmission rate was lower in SimBTKA (SimBTKA, 2.07%; StaBTKA, 3.30%; odds ratio [OR] = 1.60; p > 0.05) but statistically insignificant. SimBTKA was less costly than StaBTKA by US$ 8,422.22 per patient. No significant differences in ICU admission and death rates were found (p > 0.05) between the two groups. SimBTKA had a shorter LOS and lower cost than StaBTKA and comparable complication rates. Therefore, SimBTKA should be indicated in medically stable patients.
Total Knee Arthroplasty in Patients with Cerebral Palsy: A Large Database Analysis
Authors: Acuña Alexander J. , Burnett Robert A. , Jones Conor M. , Forlenza Enrico M. , Levine Brett R. , Della Valle Craig J.
Published: July 2024

Cerebral palsy (CP) is a neurodevelopmental condition that can result in altered gait biomechanics, joint dysfunction, and imbalance. The complications associated with total knee arthroplasty (TKA) in patients with CP have not yet been well described. Therefore, our analysis sought to compare the 90-day and 2-year complications following TKA in patients with and without CP. The PearlDiver Mariner database was utilized to identify patients with CP undergoing primary TKA between 2010 and 2020. This cohort was matched 1:4 to a control cohort without neurodegenerative disorders based on age, sex, Elixhauser Comorbidity Index (ECI), tobacco use, obesity, and diabetes. A total of 3,257 patients (657 CP patients 2,600 controls) were included in our final analysis. A multivariable logistic regression analysis was utilized to determine the risk of CP on medical and surgical complications at 90 days and all-cause revision rates at 2 years. Patients with CP had an increased risk of acute kidney injury (odds ratio [OR]: 1.66; 95% confidence interval [CI]: 1.07–2.5; p = 0.019), pneumonia (OR: 5.63; 95% CI: 3.69–8.67; p < 0.001), urinary tract infection (OR: 5.01; 95% CI: 3.85–6.52; p < 0.001), and transfusion (OR: 2.21; 95% CI: 1.50–3.23; p < 0.001). CP patients additionally had a higher incidence of emergency department (ED) visits (OR: 5.24; 95% CI: 3.76–7.32; p < 0.001) and readmissions (OR: 5.24; 95% CI: 2.57–4.96; p < 0.001). There were no differences in rates of periprosthetic joint infection (PJI; OR: 1.23; 95% CI: 0.69–2.10; p = 0.463), surgical site infection (SSI; OR: 0.51; 95% CI: 0.12–1.46; p = 0.463), and reoperation (OR: 1.35; 95% CI: 0.71–2.43; p = 0.339) at 90 days postoperatively. The all-cause revision rates at 2 years were comparable (OR: 1.02; 95% CI: 0.67–1.51; p = 0.927). In this database review, we found that CP patients have a higher risk of medical complications in the acute postoperative period following TKA. The 90-day surgical complication and 2-year revision rates in CP patients were comparable to matched controls.
A DIEP Dive into Patient Risk Factors for Hernia and Bulge Development: A Meta-regression
Authors: Rezania Nikki , Harmon Kelly A. , Frauchiger-Ankers Reilly , La-Anyane Okensama , Idrizi Keid , To Jocelyn , Ritz Ethan M. , Kurlander David E. , Shenaq Deana , Kokosis George
Published: July 2024

Background This meta-regression aims to investigate risk factors for abdominal hernia and bulge in patients undergoing deep inferior epigastric perforator (DIEP) flaps and the effect of prophylactic mesh placement on postoperative complications.

Methods A systematic search was conducted in July of 2022 in alignment with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Seventy-four studies published between 2000 and 2022 met the inclusion criteria. Sixty-four studies were included in the analysis for bulge and 71 studies were included in the analysis for hernia. Meta-regressions were run on the proportion of patients experiencing hernia or bulge to assess for patient risk factors and the role of prophylactic mesh placement. Proportions were transformed using the Freeman–Tukey double arcsine method.

Results The average rates of hernia and bulge after DIEP flaps were found to be 0.18% and 1.26%, respectively. Increased age (β = 0.0059, p = 0.0117), prior abdominal surgery (β = 0.0008, p = 0.046), and pregnancy history (β = −0.0015, p = 0.0001) were significantly associated with hernia. Active smoking (β = 0.0032, p = 0.0262) and pregnancy history (β = 0.0019, p < 0.0001) were significantly associated with bulge. Neither the perforator vessel laterality nor the number of perforator vessels harvested had any association with hernia or bulge. Prophylactic mesh placement was not associated with hernia or bulge.

Conclusion Understanding the comorbidities associated with hernia or bulge following DIEP flap breast reconstruction, such as advanced age, prior abdominal surgery, pregnancy history, and active smoking status, allows surgeons to proactively identify and educate high-risk patients. Future studies may further explore whether prophylactic mesh placement offers patients any benefit.
Imaging Classification of Exophytic HCC and Our Experience with Microwave Ablation of Type 2 Lesions
Authors: Singhal Soumil , Bhatter Pallav , Shankar Girendra , Khandelwal Anubhav , Baijal Sanjay Saran
Published: July 2024

Purpose The purpose of this article is to classify hepatocellular carcinoma (HCC) based on imaging and to evaluate the role of ultrasound-guided microwave ablation (MWA) in the management of type 2 exophytic HCC.

Materials and Methods A retrospective study was performed at our institution after approval by the Institutional Review Board. The study was undertaken from January 2017 to May 2022. Based on the location, HCC was classified and categorized on cross-sectional imaging into four types. All MWA procedures were performed using ultrasound guidance. Patients were followed up every 3 months with cross-sectional imaging.

Results During the study period, 225 lesions were reviewed. MWA was performed in 13 type 2 exophytic HCC patients. Segment 3 (38%) was the most common site when categorized as per Couinaud classification and segment 6 was the next common site. Technical success of complete ablation, evaluated by postprocedure contrast-enhanced computed tomography scan, was 100%. The median follow-up period was 24 months (range: 9–24 months). One patient presented with a residual lesion on the first follow-up at 30 days. Two other patients followed up to 9 months were free of HCC. Ten patients followed up at 1 year showed no recurrence, while 7 of them were followed up for 24 months, and 1 of whom showed multicentric recurrence which was treated by selective intra-arterial radiation therapy.

Conclusion A classification system for exophytic lesions can allow for better patient selection, planning, and reporting of ablative outcomes. MWA has performed well when ablating these technically challenging lesions with a certain degree of planning.
Identifying the underlying psychological constructs from self-expressed anti-vaccination argumentation
Authors: Holford Dawn , Lopez-Lopez Ezequiel , Fasce Angelo , Karlsson Linda C. , Lewandowsky Stephan
Published: July 2024

People’s negative attitudes to vaccines can be motivated by psychological factors—such as fears, ideological beliefs, and cognitive patterns—known as ‘attitude roots’. This study had two primary objectives: (1) to identify which of 11 known attitude roots are featured in individuals’ self-expressed reasons for negative vaccine attitudes (i.e., a linguistic analysis); (2) to explore how attitude roots present in self-expressed texts are linked to specific psychological measures. To achieve Objective 1, our study collected data from December 2022 to January 2023 from 556 participants from the US, who wrote texts to explain the reasons for their negative vaccine attitudes. The texts encompassed 2327 conceptually independent units of anti-vaccination argumentation, that were each coded for its attitude root(s) by at least two psychological experts. By allowing participants to spontaneously express their attitudes in their own words, we were able to observe how this differed from what participants reported to endorse when presented with a list of arguments. We found that there were four groups of attitude roots based on linguistic similarity in self-expression. In addition, latent class analysis of participants’ coded texts identified three distinct groups of participants that were characterised by their tendency to express combinations of arguments related to (1) fears, (2) anti-scientific conceptions, and (3) politicised perspectives. To achieve Objective 2, we collected participants’ responses to 11 validated measures of psychological constructs expected to underlie the respective 11 attitude roots, and used a correlational design to investigate how participants’ self-expressed attitude roots were linked to these measures. Logistic regressions showed that an expected psychological construct was the strongest, and significant, predictor for expression of three out of the four attitude root groups. We discuss the implications of these findings for health communicators and practitioners.
Methods for aggregating investor sentiment from social media
Authors: Liu Qing , Son Hosung
Published: July 2024

Social media-based investor sentiment proxies provide a brand new solution to recognize and measure investor sentiment. Aggregating individual social media text sentiments into public sentiments through a specific aggregation method is a necessary part of constructing an investor sentiment index for social media. The choice or design of the aggregation method directly affects whether or not the researcher can capture the sentiment of the market. This study provides the first systematic review of mainstream methods for aggregating investor sentiment from social media. In addition, we systematically discuss some of the key issues of historical researchers in aggregating investor sentiment, such as neutral sentiment text, simple aggregation of directly aggregated text, etc. The findings suggest that the aggregation method used by researchers directly affects the reliability of investor sentiment indices. Therefore, scholars should carefully choose sentiment aggregation algorithms based on the combination of datasets and sentiment tracking tools and articulate their rationale. This study provides important references for behavioral finance, social media mining, and microinvestor sentiment metrics.
Impedance-matched coplanar-waveguide metal-powder low-pass filters for cryogenic applications
Authors: Lyatti Matvey , Roth Raphael , Gundareva Irina , Grützmacher Detlev , Schäpers Thomas
Published: July 2024

We developed impedance-matched metal-powder low-pass filters based on coplanar waveguide design and characterized them at room temperature and 77.4 K. The coplanar waveguide metal-powder (CPW-MP) filters have a return loss better than 9.8 dB at frequencies up to 10 GHz at 77.4 K. We find that the filter attenuation per length scales linearly with frequency from 29 to 220 dB/m within the 1–5 GHz frequency range at 77.4 K, achieving the total attenuation above 100 dB for the 1 m-long CPW-MP filter at frequencies above 2 GHz. The CPW-MP filter integrated with the multipole LC filter demonstrates the low cut-off frequency, the attenuation above 100 dB in the stop band, and the high roll-off of 590 dB per decade. The proposed CPW-MP filter is easy to fabricate, has very good thermal-shock resistance, is flexible for integration with other types of low-pass filters, delivers the same performance as classical cryogenic filters, is more compact compared to 50 Ω coax cables with the same type of lossy dielectric, and provides ample opportunities for further miniaturization.
Synchrotron-based x-ray diffraction analysis of energetic ion-induced strain in GaAs and 4H-SiC
Authors: Chakravorty Anusmita , Boulle Alexandre , Debelle Aurélien , Manna Gouranga , Saha Pinku , Kanjilal D. , Kabiraj Debdulal
Published: July 2024

Strain engineering using ion beams is a current topic of research interest in semiconductor materials. Synchrotron-based high-resolution x-ray diffraction has been utilized for strain-depth analysis in GaAs irradiated with 300 keV Ar and 4H-SiC and GaAs irradiated with 100 MeV Ag ions. The direct displacement-related defect formation, anticipated from the elastic energy loss of Ar ions, can well explain the irradiation-induced strain depth profiles. The maximum strain in GaAs is evaluated to be 0.88% after Ar irradiation. The unique energy loss depth profile of 100 MeV Ag (swift heavy ions; SHIs) and resistance of pristine 4H-SiC and GaAs to form amorphous/highly disordered ion tracks by ionization energy loss of monatomic ions allow us to examine strain buildup due to the concentrated displacement damage by the elastic energy loss near the end of ion range (∼12 μm). Interestingly, for the case of SHIs, the strain-depth evolution requires consideration of recovery by ionization energy loss component in addition to the elastic displacement damage. For GaAs, strain builds up throughout the ion range, and the maximum strain increases and then saturates at 0.37% above an ion fluence of 3×1013 Ag/cm2. For 4H-SiC, the maximum strain reaches 4.6% and then starts to recover for fluences above 1×1013 Ag/cm2. Finally, the contribution of irradiation defects and the purely mechanical contribution to the total strain have been considered to understand the response of different compounds to ion irradiation.
Wafer-scale bonded GaN–AlN with high interface thermal conductance
Authors: Li Man , Pan Kaicheng , Ge Yijun , Huynh Kenny , Goorsky Mark S. , Fisher Timothy S. , Hu Yongjie
Published: July 2024

Wide and ultrawide bandgap semiconductors, such as GaN, play a crucial role in high-power applications, yet their performance is often constrained by thermal management challenges. In this work, we introduce a high-quality interface between GaN and AlN, prepared through wafer-scale bonding and verified via high-resolution transmission electron microscopy and transport experiments. We experimentally measured the thermal boundary conductance of the GaN–AlN interface, achieving up to 320 MW/m2K at room temperature using an ultrafast optical technique and sensitivity examinations. Non-equilibrium atomistic Green's functions and density functional theory simulations were conducted to model the interface phonon modes and their contributions to thermal transport, demonstrating good agreement with the experimental results from 80 to 300 K. Additionally, we observed a size-dependent effect on the thermal boundary conductance related to the GaN film thickness from 180 to 450 nm, which we attributed to quasi-ballistic thermal transport through molecular dynamics simulations. Our study has demonstrated a scalable processing route for wafer-sized chip packaging and provides fundamental insights to mitigate near-junction thermal resistance. Further exploration of interface engineering could facilitate co-design strategies to advanced thermal management technologies.
The photochemical trans → cis and thermal cis → trans isomerization pathways of azobenzo-13-crown ether: A computational study on a strained cyclic azobenzene system
Authors: Sisodiya Dilawar Singh , Chattopadhyay Anjan
Published: July 2024

The isomerization of azobenzo-13-crown ether can be expected to be hindered due to the polyoxyethylene linkage connecting the 2,2′-positions of azobenzene. The mixed reference spin-flip time-dependent density functional theory results reveal that the planar and rotational minima of the first photo-excited singlet state (S1) of the trans-isomer pass through a barrier (2.5–5.0 kcal/mol) as it goes toward the torsional conical intersection (S0/S1) geometry (<CNNC ≈ 98°), which is responsible for the cis isomer formation. The second excited singlet state (S2) of the trans form has a nearly planar minimum along the N–N stretching mode, which approaches a sloped S2/S1 intersection geometry. This excited state has a rotational minimum (<CNNC ≈ 99°) as well. Both these minima have a characteristic S2–S1 energy gap of 9 kcal/mol and may undergo internal conversion. A comparison of this system with an analogous 2,2′-dimethoxy-substituted azobenzene system reveals less strain in the rotational path of the latter on the S1 surface, indicating the possibility of its better trans → cis yield than the azocrown. The completely planar S2 geometry of the dimethoxy system has easy access to the linear concerted inversion path, which seems to be the reason behind its reported slightly lower π–π*(S2) yield than n–π*(S1). The thermal cis → trans isomerization path of the azobenzo-13-crown passes through a transition state (frequency 453i cm−1), which corresponds to Gibbs free energy of activation value of 26 kcal/mol in the gas-phase and isooctane. Our study also confirms that its trans isomer strongly binds Li+ among the alkali metal ions, and this observation may open up possibilities for practical applications of this azobenzo-crown.
Influence of heat transfer at the graphene–polyimide interface on laser-induced graphene formation
Authors: Park Won Gyun , Park Jeong-Hyeon , Park Sang-Chan , Kim Kiwan , Lee Eun-Ho , Ahn Jae-Hyuk
Published: July 2024

Laser-induced graphene (LIG) provides a three-dimensional porous structure of graphene, which is suitable for application to energy storage devices and flexible electronics. Controlling the morphology and structure of LIG and understanding its underlying principle are important for enhancing the performance of LIG-based devices. Here, we investigated the effects of graphene interfacing with a precursor material on the LIG formation. A CO2 laser with different powers and scan rates was irradiated on a polyimide film covered with mono-, bi-, and trilayer graphene to fabricate in situ LIG contacts. As the number of graphene layers increases, the threshold energy required for the LIG formation decreases. In addition, the interfacing graphene causes spreading and smoothing of the LIG electrodes in the in-plane direction. A numerical study on the effect of the interfacing graphene on heat transfer was also conducted. The simulation results showed that the graphene layer enhances thermal diffusion to facilitate the LIG formation; this was also observed in the experimental results. Our study on the interfacial effects of a nanomaterial on the LIG formation provides design guidelines for considering heat transfer in LIG electronics fabricated with heterogeneous materials and structures.
Role of dislocations on martensitic transformation temperatures and microstructure: A molecular dynamics study
Authors: Farache David , Mishra Saswat , Tripathi Shivam , Strachan Alejandro
Published: July 2024

Microstructure and defects strongly affect martensitic transformations in metallic alloys. Significant progress has been made in understanding the atomic-level processes that control the role of grain boundaries and precipitates in these solid-to-solid phase transformations. Yet, the role of dislocations and their structures on martensitic transformation temperature and the resulting microstructure remains unclear. Therefore, we used large-scale molecular dynamics simulations to study the forward and reverse transformation of a martensitic material modeled after Ni63Al37 under cyclic thermal loading. The simulations reveal that dislocations in the austenite phase act as one-dimensional seeds for the martensite phase, which is present at temperatures significantly above the martensite start value. We find a reduction in the dislocation density during cyclic thermal loading, which results in the increase in martensite and austenite transition temperatures, in agreement with experiments. Importantly, we extracted a critical martensitic nuclei size for developing stable domains and found that relatively low dislocation densities are needed to grow independent martensitic variants resulting in a multi-domain structure.
Effects of surface tension on the collapse time of an empty bubble
Authors: Iacono R.
Published: July 2024

The collapse of an empty spherical bubble in an ideal liquid, in the absence of viscosity and surface tension, was studied by Lord Rayleigh. Using energy conservation, he derived an exact expression for the total collapse time as a function of the initial radius of the bubble, the density of the liquid, and the far-field pressure. In the present work, we extend Rayleigh's expression to include surface tension effects. Results are found to depend on a dimensionless parameter ϵ that measures the ratio between the work done by surface tension and that done by pressure during the collapse. This parameter is small for large bubbles but can be of order unity or larger for bubbles of small radius and, eventually, small pressure. We show that the ratio between the collapse time in the presence of surface tension and Rayleigh's collapse time is proportional to a definite integral that is a smooth, monotonically decreasing function of ϵ. This function can be easily bounded analytically for any value of ϵ, yielding a simple and accurate approximation for the collapse time that, for all practical purposes, provides a complete analytical solution to the problem at hand. We finally extend results to the case of a hyperspherical collapsing empty bubble.
Laser-induced periodic surface structures on Fe ion doped LN crystal for pyroelectric SERS analysis
Authors: Ren Yingying , Luo Shenglin , An Peng , Zhao Lina , Cai Yangjian , Li Zhen
Published: July 2024

We proposed a sensor architecture for surface-enhanced Raman scattering (SERS) based on Fe ion doped LN (FLN) crystal, which was modified by large-area laser-induced periodic surface structures (LIPSS) and subsequently decorated with Ag nanoparticles (Ag NPs). Based on such a FLN/LIPSS/Ag substrate, strikingly boosted SERS enhancement was obtained at constant temperature owing to the LIPSS-related hot spot improvement. Benefiting from the pyroelectric effect of the FLN crystal, further enhanced SERS was achieved under heating and cooling processes, which can be ascribed to the additional charge transfer between molecules and Ag NPs triggered by pyroelectric potential. The experimental results highlight the high fabrication efficiency, ultrasensitivity, high uniformity, and high universality of the substrate, integrating the advantages of both LIPSS and the FLN crystal. More interestingly, selective suppression of Raman signals under cooling processes was observed, which further extends the applications of the FLN/LIPSS/Ag substrate for the detection of molecule complexes such as lake water polluted by crystal violet and 4-aminothiophenol molecules.
Ferroelectric proximity effects in two-dimensional FeSeTe
Authors: Disiena Matthew N. , Pandey Nilesh , Luth Christopher , Sloan Luke , Shattuck Reid , Singh Jatin V. , Banerjee Sanjay K.
Published: July 2024

Recent studies have shown that proximity effects are able to substantially modulate the superconducting properties of various quasi-two-dimensional layered materials such as FeSe, FeSeTe, NbSe2, and NbS2. Due to their high surface charge concentration and high dielectric constants, ferroelectric materials provide an interesting avenue for inducing proximity effects in layered superconductors. In this study, we explore the interactions between FeSeTe and the two-dimensional ferroelectrics CuInP2S6 and CuInP2Se6. We found that contrary to the normal behavior of FeSeTe, FeSeTe/CuInP2S6, and FeSeTe/CuInP2Se6 heterostructures display a peculiar two-step superconducting transition. Further testing revealed a hysteresis loop in the IV curves of these samples when measured below the critical temperature indicating the presence of disorder and domains within FeSeTe. We conclude that these domains are responsible for the two-step transition in FeSeTe and hypothesize that they are induced by the domain structure of the aforementioned ferroelectric materials.
Gravitational effects on large-scale premixed flame dynamics: From linear to nonlinear evolution
Authors: Wang Junjie , Wang Rui , Liang Geng , Yang Dewu , Xu Hui
Published: July 2024

Gravitational effects on premixed flame propagation, coupled with Darrieus–Landau instability, are investigated through direct numerical simulations under both thermal-diffusive (TD) stable and unstable situations. During the early stage of propagation, the dispersion relation between the linear growth rate σ and wavenumber k of perturbations exhibits good symmetry, allowing it to be well-fitted by the polynomial σ=c+ak−bk2. The modified Clavin–Garcia relation derived from asymptotic analysis aligns with numerical results only in the low-wavenumber region, since the significant error in the second-order coefficient bg renders it inapplicable for the high-wavenumber region. In the nonlinear regime, three morphological effects of gravity on the flame propagation have been identified: flattening the flame front, suppressing the cusp fusion rate, and promoting the new cusp generation (front splitting). The first two effects slow down the flame propagation, respectively, by reducing the overall flame front length and delaying the appearance of velocity peaks. Nevertheless, the promotion of front splitting accelerates the flame by facilitating more frequent velocity peaks arising from both cusp generation and fusion events. These various morphological effects, along with their distinct impacts on either accelerating or decelerating the flame propagation, result in significant variations in the behavior of large-scale flame propagation under different gravitational levels, despite gravity being a large-scale stabilizing effect.
Validation of predictive performance models for supersonic gas-jet nozzles at the Laboratory for Laser Energetics
Authors: McMillen K. R. , Heuer P. V. , Gjevre J. M. , Milder A. L. , Charles P. , Filkins T. , Rinderknecht H. G. , Froula D. H. , Shaw J. L.
Published: July 2024

We present results characterizing the neutral-density distributions produced by the supersonic nozzles used in experiments on the OMEGA-60 and OMEGA-EP laser systems at the University of Rochester’s Laboratory for Laser Energetics (LLE). Axisymmetric Fluent® simulations using LLE nozzle specifications capture the viscous effects, gas expansion, and shock waves that complicate flow predictions for offsets above the nozzle exit. These simulations show good agreement with neutral-density measurements obtained using a four-wave shearing interferometer. An analytical form is given for the plateau length. Fits to simulation data for boundary layer thickness, mean plateau density, and density ramps are given as functions of nozzle offset and nozzle backing pressure for a number of nozzles and gases.
Wind loads on a square high-rise building under aerodynamic interference effects of a short building in close proximity
Authors: Song Jie , Chen Wenliang , Hu Gang , Zou Lianghao
Published: July 2024

Although the interference effect of an equally high or higher building has been examined extensively, the interference effect of a short building in close proximity on the wind pressure of a high-rise building has not yet been investigated comprehensively and thoroughly. In view of the fact that a newly built wind-sensitive high-rise building is more likely to be close to neighboring shorter buildings, this research focuses on wind loads of a square high-rise building under the interference effect of a short building in close proximity. Wind pressure on the principal square building model is measured by wind tunnel test for a series of cases of interfering buildings with different heights and gap distances. In addition, computational fluid dynamics simulation is conducted for a few typical cases. Characteristics of wind flow and pressure on the principal building are then discussed in detail for three typical interfering configurations to uncover the mechanism of interference effect of a short building. Although a short interfering building in many cases tends to decrease wind loads on the high-rise building, especially for the dynamic component of wind loads, the interfering effect from a short building could induce damage to cladding structures from the increased tension caused by the asymmetrical wind pressure, channeling effect, and the wind-over-top flow over the short interfering building.
The x-ray absorption spectrum of the tert-butyl radical: An experimental and computational investigation
Authors: Schaffner Dorothee , Juncker von Buchwald Theo , Karaev Emil , Alagia Michele , Richter Robert , Stranges Stefano , Coriani Sonia , Fischer Ingo
Published: July 2024

We report the x-ray absorption spectrum (XAS) of the tert-butyl radical, C4H9. The radical was generated pyrolytically from azo-tert-butane, and the XAS of the pure radical was obtained by subtraction of spectra recorded at different temperatures. The bands in the XAS were assigned by ab initio calculations that are in very good agreement with the experimental data. The lowest energy signal in the XAS is assigned to the C1s electron transition from the central carbon atom to the singly occupied molecular orbital (SOMO), while higher transitions correspond to C1s excitations from terminal carbon atoms. Furthermore, we investigated the fragmentation of the radical following resonant C1s excitation by electron–ion-coincidence spectroscopy. Several fragmentation channels were identified. The C1s excitation of the terminal carbons is associated with a stronger fragmentation tendency compared to the lowest C1s excitation of the central carbon into the SOMO. For this core excited state, we still observe an intact parent ion, C4H9+, and a comparatively higher tendency to dissociate into CH3+ + C3H6+.
The structure of ice under confinement in periodic mesoporous organosilicas (PMOs)
Authors: Gießelmann Niels C. , Lenz Philip , Meinert Sophia-Marie , Simon Tamás , Bauer Robert P. C. , Jo Wonhyuk , Claas Sarah , Köhn Christian , Striker Nele N. , Fröba Michael , Lehmkühler Felix
Published: July 2024

We investigated the structure of ice under nanoporous confinement in periodic mesoporous organosilicas (PMOs) with different organic functionalities and pore diameters between 3.4 and 4.9 nm. X-ray scattering measurements of the system were performed at temperatures between 290 and 150 K. We report the emergence of ice I with both hexagonal and cubic characteristics in different porous materials, as well as an alteration of the lattice parameters when compared to bulk ice. This effect is dependent on the pore diameter and the surface chemistry of the respective PMO. Investigations regarding the orientation of hexagonal ice crystals relative to the pore wall using x-ray cross correlation analysis reveal one or more discrete preferred orientation in most of the samples. For a pore diameter of around 3.8 nm, stronger correlation peaks are present in more hydrophilically functionalized pores and seem to be connected to stronger shifts in the lattice parameters.
Effects of surface tension and viscosity on the impact process of droplets onto a rotational surface
Authors: Zhou Yi , Jin Zheyan , Yang Zhigang
Published: July 2024

In the present study, the impact process of droplets onto a rotational surface was experimentally studied. The influences of the rotational speed, liquid surface tension, and viscosity on the impact phenomena were carefully investigated. The phenomena of asymmetric spreading, splashing with and without liquid filament, finger formation, and secondary droplets were observed. The results showed that, at the same rotational speed, decrease in the surface tension could result in increase in the wetting length in angular direction and the wetting area. In addition, the splashing threshold was discussed based on the analysis of the lift force. In addition, increase in the linear velocity of the surface could promote the splashing behavior and generate more fingers and secondary droplets. Moreover, droplets with higher viscosity could produce more secondary droplets and less fingers. Meanwhile, droplets with higher surface tension could produce more fingers and less secondary droplets. In addition, new correlations for the spreading ratio, the number of fingers formed at the angle of 150° after impact, and the number of secondary droplets were proposed.
Spin echo small-angle neutron scattering using superconducting magnetic Wollaston prisms
Authors: Funama Fumiaki , Wolf Caitlyn M. , Weigandt Katie , Shen Jiazhou , Parnell Steven R. , Li Fankang
Published: July 2024

We show the implementation of superconducting magnetic Wollaston prisms for spin echo small-angle neutron scattering. Two calibration methods for the spin echo length are presented: one utilizing spin echo modulated small-angle neutron scattering and the other based on the neutron refraction by quartz wedge crystals. Our experimental results with polystyrene nano-particle colloids showcase the system’s efficacy in measuring both dilute and concentrated colloidal systems. Additionally, investigations into the pore diameter and pitch of a nano-porous alumina membrane demonstrate its capability in analyzing nano-porous materials. Furthermore, we discuss potential optimizations to further extend the accessible spin echo length.
Tunable thermal expansion via the magnetic phase competition in kagome magnets
Authors: Qiao Yongqiang , Liaquat Irfan , Zhu Yuhao , Guo Juan , Liang Erjun , Gao Qilong
Published: July 2024

Negative thermal expansion materials can solve the challenge of mismatched coefficients of thermal expansion of components in precision instruments, thereby improving the thermal shock resistance of devices. The adjustment of negative thermal expansion performance can improve the universality of its application. In this work, tunable thermal expansion has been achieved in Hf1−xTaxFe2 kagome magnets via magnetic phase competition. The transition from ferromagnetism to antiferromagnetism results in a sharp volume shrinkage of Hf0.83Ta0.17Fe2 within a narrow temperature range of 190–230 K, which limits its practical application. As the Ta content decreases, the ferromagnetic ground state becomes more robust and eventually suppresses the antiferromagnetism completely, achieving a negative thermal expansion in Hf0.88Ta0.12Fe2 caused by the ferromagnetic to paramagnetic transition over a wide temperature region and containing room temperature (αV = −37.63 × 10−6 K−1, 250–350 K). This work realizes the regulation of negative thermal expansion through magnetic phase competition, which provides guidance for the regulation of thermal expansion of magnetic materials in the future.
Numerical investigation of power-law flow past two side-by-side identical circular cylinders
Authors: Zhu Hongjun , Li Yingmei , Xie Yipu , Zhang Wenxiang , Zhou Tongming
Published: July 2024

The non-Newtonian flow past multiple cylinders is widely encountered in engineering applications, such as slurry transport, petroleum drilling, and heat transmission systems using hot kerosene. However, the wake characteristics of non-Newtonian flow past multiple cylinders are far from well understood. This paper reports the numerical results of power-law flow past two side-by-side identical circular cylinders with a various gap ratio (G/D = 1.1–6.0) and a power-law index (n = 0.8–1.5) at a fixed Reynolds number (Re = 100) based on the incoming uniform flow velocity. Six wake patterns are identified, including the single bluff-body regime, deflected regime, in-phase regime, anti-phase regime, and two subclasses of flip-flopping regime (FF1 and FF2 regimes). The hydrodynamic coefficients of two cylinders are sensitive to both the gap ratio and the power-law index. The wake structure evolution is closely related to the wake patterns, and six modes of wake evolution are accordingly observed. Since the apparent viscosity of power-law fluid changes with the shear rate, the distribution of local Reynolds number (ReL) around the cylinder surface varies with the wake pattern. As it goes outward along the normal direction from the cylinder surface, the ReL shows a trend of increasing and then decreasing when n < 1, while the opposite trend is observed when n > 1.
Aerodynamic interference between road vehicle and train during meeting on a single-level rail-cum-road bridge under crosswind
Authors: Lei Ming , Zhu Jin , Wu Mengxue , Li Yongle , Ti Zilong
Published: July 2024

A single-level rail-cum-road bridge is a relatively new type of bridge structure that accommodates both roadway and railway traffic on the same level. The aerodynamic interactions between road vehicles, trains, and the bridge deck under strong crosswind are significant, potentially posing safety risks to both vehicles and trains. This study aims to elucidate the aerodynamic interference between a road vehicle and a train during meeting on a single-level rail-cum-road bridge under crosswind. To achieve this, a three-dimensional, incompressible, unsteady Reynolds averaged Navier–Stokes method is utilized to simulate the meeting process between a van and a train on a prototype single-level rail-cum-road bridge under crosswind. Using an established computational fluid dynamics numerical model, the flow structure and aerodynamic loads of the van–train–bridge system under crosswind are studied. The results show that the auxiliary facilities on the bridge deck (such as pedestrian guardrails and anti-glare barriers) significantly alter the flow field around the van and train, affecting their aerodynamic characteristics. Additionally, the aerodynamic interference between the van and the train during their meeting under crosswind is substantial. The aerodynamic coefficients of the van and train, in terms of both magnitude and fluctuation, increase significantly with their driving speeds during the meeting process under crosswind. Furthermore, this aerodynamic interference intensifies as the lateral distance between the van and the train decreases during the meeting under crosswind.
Threshold voltage modulation on a CTL-based monolithically integrated E/D-mode GaN inverters platform with improved voltage transfer performance
Authors: Jiang Yang , Du FangZhou , Wen KangYao , Zhang Yi , Li MuJun , Tang ChuYing , Deng ChenKai , Yu WenYue , Wang ZhongRui , Wang Qing , Yu HongYu
Published: July 2024

This work demonstrates a high-performance monolithically integrated GaN inverters platform, which incorporates enhancement-mode (E-mode) and depletion-mode (D-mode) GaN high-electron-mobility transistors (HEMTs) simultaneously using an Al:HfOx-based charge trapping layer. The developed E-mode HEMT exhibits a positive threshold voltage of 2.6 V, a high ON–OFF current ratio of 1.9 × 108, a current density of 376 mA/mm, and an ON-resistance of 15.31 Ω·mm. Moreover, the direct-coupled field-effect-transistor logic (DCFL) GaN inverter was characterized with and without D-mode device threshold voltage (VTH) modulation, demonstrating improved output swing and switching threshold shift by proposed VTH modulation. The optimized DCFL GaN inverter manifests a switching threshold of 2.34 V, a logic voltage output swing of 4.98 V, and substantial logic-low and logic-high noise margins of 2.16 and 2.49 V, respectively, at a supply voltage of 5 V. These results present a promising approach toward realizing monolithically integrated GaN logic circuits for power IC applications.