bluuebunny/crossref_metadata_2025 huggingface dataset:
Frankfurter Erklärung
Authors: Bechtel Peter
Published: May 2022

Der Bundesverband Pflegemanagement fordert eine konsequente Einbindung der Pflege und des Pflegemanagements in die politische Entscheidungsfindung.
Anamnese: Grundgerüst und hilfreiche Tipps
Authors: Bierbach Elvira
Published: May 2022

Das Anamnese-Grundgerüst enthält neben den persönlichen Kenndaten Fragen zu Beschwerden, bisherigen Behandlungen und deren Resultate sowie Begleitsymptomen. Hinzu kommen Fragen zu unter anderem Vorerkrankungen, Operationen, Medikamenteneinnahme, Allergien und Unverträglichkeiten, zur Sozial- und Familienanamnese sowie zum Ernährungsverhalten. Für besondere Zielgruppen wie Kleinkinder und Säuglinge, ältere Menschen, Schmerzpatienten und Demenzpatienten gibt es zusätzliche spezifische Fragen.
Comparison of Assist/Control Ventilation with and without Volume Guarantee in Term or Near-Term Infants
Authors: Bezirganoglu Handan , Okur Nilufer , Buyuktiryaki Mehmet , Oguz Serife S. , Dizdar Evrim A. , Sari Fatma N.
Published: May 2022

Objectives This study aimed to compare the effects of volume guarantee (VG) combined with assist/control (AC) ventilation to AC alone on hypocarbia episodes and extubation success in infants born at or near term.

Methods In this prospective cohort study, infants >34 weeks of gestation at birth, who were born in our hospital supported by synchronized, time-cycled, pressure limited, assist/control ventilation (AC) or assist-controlled VG mechanical ventilation (AC + VG) were included. After admission, infants received either AC or VG + AC using by Leoni Plus ventilator. The ventilation mode was left to the clinician. In the AC group, peak airway pressure was set clinically. In the VG + AC group, desired tidal volume was set at 5 mL/kg, with the ventilator adjusting peak inspiratory pressure to deliver this volume. The study was completed once the patient extubated.

Results There were 35 patients in each group. Incidence of hypocarbia was lower in the VG + AC compared with AC (%17.1 and 22.8%, respectively) but statistically not significant. Out-of-range partial pressure of carbon dioxide (PCO2) levels were lower in the VG + AC group and it reached borderline statistical significance (p = 0.06). The median extubation time was 70 (42–110) hours in the VG + AC group, 89.5 (48.5–115.5) hours in the AC group, and it did not differ between groups (p = 0.47).

Conclusion We found combining AC and VG ventilation compared with AC ventilation alone yielded similar hypocarbia episodes and extubation time for infants of >34 gestational weeks with borderline significance lower out-of-range PCO2 incidence.

Key Points
Heterogeneity of Drug Allergies and Reaction Lists in Two U.S. Health Care Systems' Electronic Health Records
Authors: Yerneni Sharmitha , Shah Sonam N. , Blackley Suzanne V. , Ortega Carlos A. , Blumenthal Kimberly G. , Goss Foster , Seger Diane L. , Wickner Paige G. , Mancini Christian M. , Bates David W. , Zhou Li
Published: May 2022

Background Health care institutions have their own “picklist” for clinicians to document adverse drug reactions (ADRs) into the electronic health record (EHR) allergy list. Whether the lack of a nationally standardized picklist impacts clinician data entries is unknown.

Objectives The objective of this study was to assess the impact of defined reaction picklists on clinical documentation and, therefore, downstream analytics and clinical research using these data at two institutions.

Methods ADR data were obtained from the EHRs of patients who visited the emergency department or outpatient clinics at Brigham and Women's Hospital (BWH) and University of Colorado Hospital (UCH) from 2013 to 2018. Reported drug class ADR prevalences were calculated. We investigated the reactions on each picklist and compared the top 40 reactions at each institution, as well as the top 10 reactions within each drug class.

Results Of 2,160,116 patients, 640,444 (30%) had 928,973 active drug allergies. The most commonly reported drug class allergens were similar between BWH and UCH. BWH's picklist had 48 reactions, and UCH's had 160 reactions; 29 reactions were shared by both picklists. While the top four reactions overall (rash, GI upset/nausea/vomiting, hives, itching) were identical between sites, reactions by drug class exhibited greater documentation diversity. For example, while the summed prevalence of swelling-related reactions to angiotensin-converting-enzyme inhibitors was comparable across sites, swelling was represented by two terms (“swelling,” “angioedema”) at BWH but 11 terms at UCH (e.g., “swelling,” “edema,” by body locality).

Conclusion The availability and granularity of reaction picklists impact ADR documentation in the EHR by health care providers; picklists may partially explain variations in reported ADRs across health care systems.
Haploinsufficiency of PRRT2 Leading to Familial Hemiplegic Migraine in Chromosome 16p11.2 Deletion Syndrome
Authors: Sen Kuntal , Genser Ilyse , DiFazio Marc , DiSabella Marc
Published: May 2022

Microdeletion in the 16p11.2 loci lead to a distinct neurodevelopmental disorder with intellectual disability and autism spectrum disorder in addition to dysmorphia, macrocephaly, and increased body mass index. One of the deleted genes in this region is PRRT2 which codes for proline-rich transmembrane protein 2. Heterozygous variants in PRRT2 cause four distinct neurological disorders including benign familial infantile epilepsy (BFIE), paroxysmal kinesigenic dyskinesia (PKD), PKD with infantile convulsions, and familial hemiplegic migraine (FHM). A 13-year-old male with a known history of 16p11.2 deletion and resultant cognitive delay presented with sudden onset of headache, left-sided weakness, facial droop, and aphasia concerning for acute ischemic stroke. Magnetic resonance imaging of the brain was performed urgently which did not reveal any acute processes and his presentation met criteria for hemiplegic migraine. There have been reports of PKD and BFIE in this microdeletion syndrome; however, our proband is the first case that presented with FHM related to haploinsufficiency of PRRT2. This report highlights the importance of counseling patient families regarding acute paroxysmal presentations in this syndrome.
Seroprevalence of MOG and AQP4 Antibodies and Outcomes in an Indian Cohort of Pediatric Acquired Demyelinating Syndromes
Authors: Sankhyan Naveen , Rawat Amit , Vyas Sameer , Sahu Jitendra Kumar , Bhagwat Chandana , Madaan Priyanka , Saini Lokesh , Saini Arushi Gahlot , Suthar Renu , Sukhija Jaspreet , Jayashree Murlidharan
Published: May 2022

This study aimed to determine the seropositivity of myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) and aquaporin-4 antibodies (AQP4-Ab) and outcomes in children with acquired demyelinating syndromes (ADSs). Children (6 months–15 years) with suspected ADS were enrolled and tested for MOG-Ab and AQP4-Ab prospectively over 18 months at a tertiary care hospital in North India. Children with proven nonimmune-mediated neurological disorders were enrolled as controls. Of 79 children with suspected ADS, 66 were enrolled. Among the enrolled children with ADS, acute demyelinating encephalomyelitis (ADEM) (25) was the most common first clinical event followed by optic neuritis (ON) (20) and transverse myelitis (TM) (19; one child had ON and TM simultaneously [neuromyelitis optica spectrum disorders [NMOSDs]]), while two children had clinically isolated syndrome (CIS) apart from ON and TM. Fourteen (21.2%, confidence interval [CI] 11.3–31.1) tested positive for one antibody (12 [18.1%; 95% CI 10.5–25.5%] for MOG-Ab and 2 [3%; 95% CI 0–7.2%] for AQP4-Ab). None of the 62 controls tested positive for any antibody. The final diagnosis in those with the monophasic ADS was ADEM (21), ON (13), TM (16), and other CIS (1) while that in children with recurrent events was multiphasic disseminated encephalomyelitis (MDEM) (2), NMOSD (3), ADEM-ON (4), recurrent ON (4), and MS (2). Among those with the first event, 4/51 (7.8%; 95% CI 0.5–15.2%) were MOG-Ab positive and 2 AQP4-Ab positive, whereas 8/15 (53.3% [95% CI 28.1–78.6%]) with recurrent events (MDEM [2], ADEM-ON [4], recurrent ON [1], and recurrent TM [1]) were MOG-Ab positive. Hence, MOG-Abs are the most common antibodies detected in one in five children with pediatric ADS, especially in relapsing disease. AQP4-Abs are rare in children with ADS.
Video-Assisted Informed Consent in a Clinical Trial of Resuscitation of Extremely Preterm Infants: Lessons Learned
Authors: Odackal Namrita J. , Caruso Catherine G. , Klitzman Melissa , Rincon Monica , Byrne Bobbi J. , Winter Jameel , Petroni Gina R. , Fairchild Karen D. , Warren Jamie B.
Published: May 2022

Objective Obtaining informed consent for clinical trials is challenging in acute clinical settings. For the VentFirst randomized clinical trial (assisting ventilation during delayed cord clamping for infants <29 weeks' gestation), we created an informational video that sites could choose to use to supplement the standard in-person verbal and written consent. Using a postconsent survey, we sought to describe the impact of the video on patient recruitment, satisfaction with the consent process, and knowledge about the study.

Study Design This is a descriptive survey-based substudy.

Results Of the sites participating in the VentFirst trial that obtained institutional review board (IRB) approval to allow use of the video to supplement the standard informed consent process, three elected to participate in the survey substudy. From February 2018 to January 2021, 82 women at these three sites were offered the video and completed the postconsent survey. Overall, 73 of these 82 women (89%) consented to participate in the primary study, 78 (95%) indicated the study was explained to them very well or extremely well, and the range of correct answers on five knowledge questions about the study was 63 to 98%. Forty-six (56%) of the 82 women offered the video chose to watch it. There were no major differences in study participation, satisfaction with the consent process, or knowledge about the study between the women who chose to watch or not watch the video.

Conclusion Watching an optional video to supplement the standard informed consent process did not have a major impact on outcomes in this small substudy. The ways in which audiovisual tools might modify the traditional informed consent process deserve further study.

Key Points
Intra-Parenchymal Cerebellar Metastasis—A Rare Presentation of Castration-Resistant Prostate Cancer
Authors: Ibrahim Sufyan , Reddy Vyjayanth , Menon Girish
Published: May 2022

Intracranial metastases from prostate carcinoma are uncommon and usually manifest as dural secondaries in the supratentorial compartment. We present an unusual case of intra-parenchymal posterior fossa prostatic metastasis in a 61-year-old gentleman and discuss the diagnostic and management challenges involved. A 61-year-old hypertensive, diabetic man presented with gait unsteadiness for 1-month duration and no other neurological deficits. He had previously undergone bilateral orchiectomy for prostate carcinoma with multiple osseous metastases. Magnetic resonance imaging showed a well-defined lobulated, intraventricular, peripherally enhancing lesion in the fourth ventricle with obstructive hydrocephalus. He underwent sub-occipital craniectomy and decompression, and histological examination was consistent with metastatic prostate adenocarcinoma. Although cerebellar secondaries are atypical, a suspicion of metastasis should be upheld in all patients with the history of prostate carcinoma, regardless of their location and radiological characteristics of the intracranial lesion.
Diversity in Machine Learning: A Systematic Review of Text-Based Diagnostic Applications
Authors: Fitzsimmons Lane , Dewan Maya , Dexheimer Judith W.
Published: May 2022

Objective As the storage of clinical data has transitioned into electronic formats, medical informatics has become increasingly relevant in providing diagnostic aid. The purpose of this review is to evaluate machine learning models that use text data for diagnosis and to assess the diversity of the included study populations.

Methods We conducted a systematic literature review on three public databases. Two authors reviewed every abstract for inclusion. Articles were included if they used or developed machine learning algorithms to aid in diagnosis. Articles focusing on imaging informatics were excluded.

Results From 2,260 identified papers, we included 78. Of the machine learning models used, neural networks were relied upon most frequently (44.9%). Studies had a median population of 661.5 patients, and diseases and disorders of 10 different body systems were studied. Of the 35.9% (N = 28) of papers that included race data, 57.1% (N = 16) of study populations were majority White, 14.3% were majority Asian, and 7.1% were majority Black. In 75% (N = 21) of papers, White was the largest racial group represented. Of the papers included, 43.6% (N = 34) included the sex ratio of the patient population.

Discussion With the power to build robust algorithms supported by massive quantities of clinical data, machine learning is shaping the future of diagnostics. Limitations of the underlying data create potential biases, especially if patient demographics are unknown or not included in the training.

Conclusion As the movement toward clinical reliance on machine learning accelerates, both recording demographic information and using diverse training sets should be emphasized. Extrapolating algorithms to demographics beyond the original study population leaves large gaps for potential biases.
Applicability of the single-layer flat-coil-oscillator technology-based vibration and vibro-acoustic sensors in medical and biological study of the cardiovascular system: Advantages and perspectives of the carotid pulse wave registration
Authors: Gevorgyan S. G. , Khachunts A. S. , Gevorgyan G. S. , Tumanian A. A. , Tadevosyan N. E.
Published: May 2022

The possibility and feasibility of using the single-layer flat-coil-oscillator (SFCO) technology-based vibration and vibro-acoustic sensors in diagnostic devices and biomedical studies of the cardiovascular system are discussed in this paper. Using an example of recording pulse waves of left carotid artery and their analysis, the information content of the data recorded by these sensors in a number of cases is shown—assessment of age-related changes in the stiffness of the vascular wall, assessment of the dynamics of systolic volume, reflecting myocardial contractility, and rhythm disturbance (extra-systole and arrhythmia). These sensors are shown to be promising in recording heart sounds due to their high sensitivity. The possibility of assessing the dynamics of relaxation of the cardiovascular system after exercise (stress test) is shown. The advantages of using SFCO vibration and vibro-acoustic sensors are high sensitivity, ease of use, and no need to train specialists. These advantages open new perspectives for their implementation in mobile wearable “smart” devices for individual monitoring.
Stability analysis of multiplayer games on adaptive simplicial complexes
Authors: Schlager Daniela , Clauß Konstantin , Kuehn Christian
Published: May 2022

We analyze the influence of multiplayer interactions and network adaptation on the stability of equilibrium points in evolutionary games. We consider the Snowdrift game on simplicial complexes. In particular, we consider as a starting point the extension from only two-player interactions to coexistence of two- and three-player interactions. The state of the system and the topology of the interactions are both adaptive through best-response strategies of nodes and rewiring strategies of edges, respectively. We derive a closed set of low-dimensional differential equations using pairwise moment closure, which yields an approximation of the lower moments of the system. We numerically confirm the validity of these moment equations. Moreover, we demonstrate that the stability of the fixed points remains unchanged for the considered adaption process. This stability result indicates that rational best-response strategies in games are very difficult to destabilize, even if higher-order multiplayer interactions are taken into account.
Inverse algorithm for extraction of multiple parameters using analytical model of eddy current response
Authors: Contant Stephane , Klein Geoffrey , Morelli Jordan , Krause Thomas W.
Published: May 2022

Eddy current (EC) technology is commonly used for detecting flaws, measuring geometric parameters, or determining properties of conducting materials. However, the measurement of a particular parameter can become more challenging if multiple influential parameters vary simultaneously. In particular, eddy current-based measurement of separation (gap) between a pressure tube (PT) and a calandria tube (CT) in the fuel channels of CANDU® reactors is made more difficult by variations in PT wall thickness, resistivity, and probe lift-off. An analytical model of the EC response to changes in PT–CT gap has been developed by approximating the geometry of the PT within the larger diameter CT as a pair of concentric tubes, where gap is varied by changing the CT radius. In this article, this model is used in combination with an error minimization algorithm to construct an inverse algorithm for the extraction of PT–CT gap, PT resistivity (ρ), and PT wall thickness (WT) from measured multi-frequency eddy current signals. Application of a linear regression tool in MATLAB, with fourth-order polynomial fitting of modeled data with varying ρ and WT as a function of PT–CT gap, is used to obtain coefficients that depend on ρ and WT. Output of multidimensional fitting of these coefficients is scaled and rotated to calibration data. Finally, implementation of an error minimization algorithm in MATLAB is used to produce estimates of multiple target parameters from experimental data. Simultaneous extraction of either one, two, or three parameters is examined, using experimental data obtained at frequencies used for in-reactor inspection of 4.2, 8, and 16 kHz, or just two frequencies of 4.2 and 8 kHz. Under full gap variation conditions, the inverse algorithm predicts gap to within 0.1 mm at gaps between 0 and 9 mm and to within 0.4 mm at gaps between 9 and 18 mm. PT resistivity is predicted to within 1 μΩ cm (2% relative error) and PT wall thickness within 0.03 mm (1% relative error) when each is the only extracted parameter. An excellent agreement between actual and predicted values of gap demonstrates the potential of the inverse algorithm for application to in-reactor gap measurement and simultaneous extraction of either PT wall thickness or resistivity when the other parameter is known. The extraction of PT resistivity may be particularly useful, as this parameter cannot otherwise currently be measured in-reactor.
Scrutinizing thermally stimulated current transients originating from trapped charges in organic semiconductors: A drift-diffusion study
Authors: Vael Camilla , Jenatsch Sandra , Züfle Simon , Nüesch Frank , Ruhstaller Beat
Published: May 2022

Thermally stimulated current (TSC) is a widely used technique to assess trap states and extract their density, energy, and capture rate using analytical expressions. In many cases, the latter are derived from physical models pertaining to inorganic semiconductors stipulating the absence of space charge or constant lifetime of free charge carriers. Especially for organic semiconductors, the validity of these equations can, therefore, be argued. Here, we investigate the validity range of this approach by fitting the classical equations to synthetic TSC data obtained from drift-diffusion simulation using representative input parameters for organic semiconductors. We find that the equation derived for slow recapture rate as well as the initial rise method provide excellent trap parameter predictions. On the other hand, the equation using the temperature of the peak current as well as the one derived for fast retrapping have a limited range of validity. An important merit of drift-diffusion modeling is the possibility to access local variables such as charge carrier density, electric field, and recombinaton. We unravel that a small fraction of traps nearby the electrode cannot be emptied even at high temperature due to the diffusion of charge carriers from the electrode into the semiconductor. Additionally, we find that an important electrostatic factor relates the extracted charge carriers measured by the external circuit and the input trap density. For the homogeneously distributed trap states used here, this factor is precisely two. Finally, extensions of the model are analyzed by implementing temperature and field dependent mobility into the drift-diffusion model.
Protein conformational changes and protonation dynamics probed by a single shot using quantum-cascade-laser-based IR spectroscopy
Authors: Schubert Luiz , Langner Pit , Ehrenberg David , Lorenz-Fonfria Victor A. , Heberle Joachim
Published: May 2022

Mid-IR spectroscopy is a powerful and label-free technique to investigate protein reactions. In this study, we use quantum-cascade-laser-based dual-comb spectroscopy to probe protein conformational changes and protonation events by a single-shot experiment. By using a well-characterized membrane protein, bacteriorhodopsin, we provide a comparison between dual-comb spectroscopy and our homebuilt tunable quantum cascade laser (QCL)-based scanning spectrometer as tools to monitor irreversible reactions with high time resolution. In conclusion, QCL-based infrared spectroscopy is demonstrated to be feasible for tracing functionally relevant protein structural changes and proton translocations by single-shot experiments. Thus, we envisage a bright future for applications of this technology for monitoring the kinetics of irreversible reactions as in (bio-)chemical transformations.
DFT+U within the framework of linear combination of numerical atomic orbitals
Authors: Qu Xin , Xu Peng , Jiang Hong , He Lixin , Ren Xinguo
Published: May 2022

We present a formulation and implementation of the density functional theory (DFT)+U method within the framework of linear combination of numerical atomic orbitals (NAO). Our implementation not only enables single-point total energy and electronic-structure calculations but also provides access to atomic forces and cell stresses, hence allowing for full structure relaxations of periodic systems. Furthermore, our implementation allows one to deal with non-collinear spin texture, with the spin–orbit coupling (SOC) effect treated self-consistently. The key aspect behind our implementation is a suitable definition of the correlated subspace when multiple atomic orbitals with the same angular momentum are used, and this is addressed via the “Mulliken charge projector” constructed in terms of the first (most localized) atomic orbital within the d/f angular momentum channel. The important Hubbard U and Hund J parameters can be estimated from a screened Coulomb potential of the Yukawa type, with the screening parameter either chosen semi-empirically or determined from the Thomas–Fermi screening model. Benchmark calculations are performed for four late transition metal monoxide bulk systems, i.e., MnO, FeO, CoO, and NiO, and for the 5d-electron compounds IrO2. For the former type of systems, we check the performance of our DFT+U implementation for calculating bandgaps, magnetic moments, electronic band structures, as well as forces and stresses; for the latter, the efficacy of our DFT+U+SOC implementation is assessed. Systematic comparisons with available experimental results, especially with the results from other implementation schemes, are carried out, which demonstrate the validity of our NAO-based DFT+U formalism and implementation.
Carbon nanotube logic gates: An interplay of spin and light
Authors: Shah Khurshed A. , Parvaiz M. Shunaid , Dar G. N. , Misra Prabhakar
Published: May 2022

Carbon nanotubes (CNTs) are known to be the future of modern electronic devices due to their unique structure and extraordinary properties. In this paper, we modeled a first of its kind combinational carbon nanotube device consisting of a lanthanum strontium manganite molecule fused near the left CNT electrode and four-atom boron–nitrogen dopant atoms substituted near the right CNT electrode. Spin-resolved transport properties are studied using density functional theory. It is observed from the results that spin-resolved transport properties highly depend on the type of magnetic field applied and light conditions. The device shows efficient switching pattern and high spin filtration. The observations are made by calculating I–V characteristics, spin dependent transmission spectra, and molecular projected self-consistent Hamiltonian orbitals. Using light and spin polarization dependent properties, we have designed and realized the logic operations of and, or, and not gates. The study is useful to design a number of futuristic spin and light controlled electronic devices such as transistors, amplifiers, and oscillators.
Control of the shape of bubble growth on underwater substrates with different sizes of superhydrophobic circles
Authors: Qiao Shuai , Cai Chujiang , Chen Wenxin , Pan Chong , Liu Yanpeng
Published: May 2022

Inspired by the everyday experience of changing the shape of a blown-up balloon by imposing a constraint, a method to control the shape of underwater bubbles is proposed by tangential constraint forces generated by the wettability difference (WD), and two bubble growth modes are distinguished based on the tangential constraint force strength and the minimum apparent contact angle (CA) of the bubble after the WD constraint. First, the critical growth shape of the bubble with a combined shape of a vertical cylinder and hemispherical top is identified, and its corresponding critical contact radius RCritical = 2.7 mm is solved by the Young–Laplace equation. Then, the effects of the radii of the superhydrophobic circle (SBC) on the bubble growth shapes are studied experimentally. The result shows that as the SBC radius decreases, the minimum apparent CA of the bubble decreases, and the minimum tangential constraint forces increase. Therefore, the bubble growth mode changes from the bell mode (with a minimum apparent CA greater than 90°) with a weaker constraint to the Ω mode (with a minimum apparent CA less than 90°) with a stronger constraint, and the bubble growth shape tends toward spherical from a flattened sphere. The maximum bubble trapping rate, Laplace pressure difference at the apex and bottom of the bubble, the aspect ratio, and the bubble filling ratio also increase as the SBC radius deceases. Furthermore, our results suggest that the proper WD-patterned arrays on underwater substrates can enhance their application efficiency, and the size of SBCS # R4 is probably the best choice in all cases.
Influencing the coupling between network building blocks in CdSe/CdS dot/rod aerogels by partial cation exchange
Authors: Rusch Pascal , Lübkemann Franziska , Borg Hadir , Eckert J. Gerrit , Dorfs Dirk , Bigall Nadja C.
Published: May 2022

The assembly of CdSe/CdS dot/rod nanocrystals (NCs) with variable length of ZnS tips into aerogel networks is presented. To this end, a partial region selective cation exchange procedure is performed replacing Cd by Zn starting at the NC tip. The produced aerogel networks are investigated structurally and optically. The networks of tip-to-tip connected NCs have an intricate band structure with holes confined to the CdSe cores while electrons are delocalized within the CdS also within connected building blocks. However, the ZnS tips act as a barrier of variable length and strength between the NC building blocks partly confining the electrons. This results in NC based aerogel networks with tunable strength of coupling between building blocks.
Thermal budget increased alloy disorder scattering of 2DEG in III–N heterostructures
Authors: Yu Hao , Parvais Bertrand , Zhao Ming , Rodriguez Raul , Peralagu Uthayasankaran , Alian Alireza , Collaert Nadine
Published: May 2022

High-temperature processing steps are frequently used in manufacture of AlGaN/(AlN/)GaN high electron mobility transistors (HEMTs). The thermal budgets drive Al diffusion into the GaN channel, increase alloy disorder scattering (ADS) of the two-dimensional-electron-gas (2DEG), and degrade the 2DEG mobility. By correlating the ADS to device thermal budget, we propose an analytical model to calculate the ADS limited mobility as a function of Al diffusion lengths (LD,Al) in AlGaN/(AlN/)GaN HEMTs. The simulation indicates that the ADS is a significant mobility degradation mechanism whose scattering rate increases with the 2DEG density and the LD,Al. The findings explain the generally observed trends in the literature that the 2DEG mobility and sheet resistances of GaN heterostructures degrade with increased thermal budgets, especially after >900 °C processing.
The Simons Observatory: A large-diameter truss for a refracting telescope cooled to 1 K
Authors: Crowley Kevin D. , Dow Peter , Shroyer Jordan E. , Groh John C. , Dober Bradley , Spisak Jacob , Galitzki Nicholas , Bhandarkar Tanay , Devlin Mark J. , Dicker Simon , Gallardo Patricio A. , Harrington Kathleen , Iuliano Jeffrey , Johnson Bradley R. , Johnson Delwin , Kofman Anna M. , Kusaka Akito , Lee Adrian , Limon Michele , Nati Federico , Orlowski-Scherer John , Page Lyman , Randall Michael , Teply Grant , Tsan Tran , Wollack Edward J. , Xu Zhilei , Zhu Ningfeng
Published: May 2022

We present the design and measured performance of a new carbon fiber strut design that is used in a cryogenically cooled truss for the Simons Observatory small aperture telescope. The truss consists of two aluminum 6061 rings separated by 24 struts. Each strut consists of a central carbon fiber tube fitted with two aluminum end caps. We tested the performance of the strut and truss by (i) cryogenically cycling and destructively pull-testing strut samples, (ii) non-destructively pull-testing the final truss, and (iii) measuring the thermal conductivity of the carbon fiber tubes. We found that the strut strength is limited by the mounting fasteners and the strut end caps, not the epoxy adhesive or the carbon fiber tube. This result is consistent with our numerical predictions. Our thermal measurements suggest that the conductive heat load through the struts (from 4 to 1 K) will be less than 1 mW. This strut design may be a promising candidate for use in other cryogenic support structures.
Different photocurrent response of Cs4PbBr6 particles
Authors: Pu Lei , Gu Yarong , Meng Qian , Pang Qi , Lu Aijiang , Zhao Lijuan
Published: May 2022

Zero-dimensional (0D) all-inorganic cesium lead halide perovskites, particularly Cs4PbBr6, have been attracting wide attention due to their excellent optical properties and stability. The research also focuses on the origin of green emission from Cs4PbBr6, which has a bandgap located in the ultraviolet B (UVB) region. So far, both Cs4PbBr6 without visible emission and with green emission have been successfully prepared; however, the origin of green emission remains controversial. Photocurrent response is one of the effective approaches to explore how the photo-excited carriers influence the photo-physical properties of materials. In our study, Cs4PbBr6 particles without visible emission and with green emission were synthesized and their photocurrent response was investigated. The former showed a positive photocurrent response, while the latter showed a negative photocurrent response. The negative response was believed to be due to a built-in electric field constructed by the charged excitons in green-emissive Cs4PbBr6. From our calculations, numerous vacancies of Br are easier to appear in green-emissive Cs4PbBr6 lattices, which could combine the neutral excitons to form charged excitons. This work may contribute to the explanation of the origin of green emission of Cs4PbBr6 to some extent.
Numerical study on gas–liquid two phase flow characteristic of multistage electrical submersible pump by using a novel multiple-size group (MUSIG) model
Authors: Qiaorui Si , Ali Asad , Biaobiao Wang , Wang Peng , Bois Gerard , Jianping Yuan , Kubar Ameer Ali
Published: May 2022

Electrical submersible pumps (ESPs) face enormous challenges in the petroleum industry while handling gas–liquid two-phase flow. The major difficulty is caused by the accumulation of gas bubbles inside ESP-impellers, which results in mild to severe degradation in pump performance. Therefore, to analyze the influence of gas entrainment and bubble size, a combination of experimental and numerical analysis is performed on a five-stage mixed-flow ESP in the present study. The experiments are first conducted to analyze the performance of ESP under pure water conditions at different rotating speeds, followed by the gas–liquid two-phase flow experiments that are performed at constant rotating speed (1475 r/min) and for a wide range of inlet gas void fractions (IGVFs). For numerical calculations, a novel multiple-size group (MUSIG) model is applied in ANSYS CFX to analyze the performance and different flow patterns in ESP in different IGVFs and understand the coalescence and breakup phenomena of gas bubbles in the impeller flow passage. The simulation results from the MUSIG model are compared with the Euler–Euler two-fluid model and test results. The MUSIG model can more accurately predict the changes in the performance and internal flow-field of ESP under two-phase flow conditions. Moreover, when the MUSIG model is used to calculate the two-phase flow of the ESP, the first-stage impeller has a higher head than other stages because the flow inside the second and other stages is affected by the disoriented flow coming from the first-stage diffuser and other return channels. Furthermore, this study gives an insight into the comprehensive application of the novel MUSIG model for complex turbo-machine designs such as ESP.
Flame folding and conditioned concentration profiles in moderately intense turbulence
Authors: Lipatnikov Andrei N. , Sabelnikov Vladimir A.
Published: May 2022

While the flamelet paradigm offers the opportunity to simplify computations of mean species concentrations in turbulent flames, a widely accepted criterion of the validity of this paradigm has not yet been elaborated. In this regard, different physical mechanisms are discussed, and flame folding is one of them. The present work aims at exploring the eventual influence of flame folding on the local flame structure in a turbulent flow. For this purpose, a new diagnostic technique was applied to processing complex-chemistry direct numerical simulation data obtained earlier from a lean hydrogen-air turbulent flame [Dave and Chaudhuri, J. Fluid Mech. 884, A46 (2020)]. The technique consists of counting crossing numbers Nf for a cold boundary of the local reaction zone and a ray normal to the mean flame brush, followed by analyzing statistics sampled from rays characterized by Nf≥3. More specifically, profiles of species mole fractions, temperature, heat release rate, and species production rates, conditioned to combustion progress variable and either Nf or axial distance Δx between two neighboring reaction zones, are sampled and compared with the counterpart profiles obtained from the laminar flame. Results show that these doubly conditioned profiles are close to each other for various crossing numbers or for various axial distances even if the distance is as small as half laminar flame thickness. The lack of a substantial effect of the crossing number or the axial distance on the doubly conditioned profiles implies that small-scale flame folding does not limit the validity of the flamelet paradigm.
Influence of salt on the formation and separation of droplet interface bilayers
Authors: Huang Yaoqi , Chandran Suja Vineeth , Amirthalingam Layaa , Fuller Gerald G.
Published: May 2022

Phospholipid bilayers are a major component of the cell membrane that is in contact with physiological electrolyte solutions including salt ions. The effect of salt on the phospholipid bilayer mechanics is an active research area due to its implications for cellular function and viability. In this manuscript, we utilize droplet interface bilayers (DIBs), a bilayer formed artificially between two aqueous droplets, to unravel the bilayer formation and separation mechanics with a combination of experiments and numerical modeling under the effects of K+, Na+, Li+, Ca2+, and Mg2+. Initially, we measured the interfacial tension and the interfacial complex viscosity of lipid monolayers at a flat oil–aqueous interface and show that both properties are sensitive to salt concentration, ion size, and valency. Subsequently, we measured DIB formation rates and show that the characteristic bilayer formation velocity scales with the ratio of the interfacial tension to the interfacial viscosity. Next, we subjected the system to a step strain by separating the drops in a stepwise manner. By tracking the evolution of the bilayer contact angle and radius, we show that salt influences the bilayer separation mechanics, including the decay of the contact angle, the decay of the bilayer radius, and the corresponding relaxation time. Finally, we explain the salt effect on the observed bilayer separation by means of a mathematical model comprising the Young–Laplace and evolution equations.
Fanconi syndrome in a patient receiving pre-exposure prophylaxis for HIV infection: case report
Authors: Drak Douglas , Lin Jasper , Gowers Andrew , Gracey David M.
Published: May 2022

Background Tenofovir disoproxil is efficacious in the preventing HIV infection as part of a pre-exposure prophylaxis (PrEP) regimen. Although its use has been associated with impaired renal function, instances of Fanconi syndrome are extremely rare. This may change with increased uptake of PrEP. Methods A 55-year-old male patient (he/him/his) was commenced on PrEP with a baseline estimated glomerular filtration rate (eGFR) of approximately 60 mL/min/1.73 m2. Results Within 6 months, he developed new and worsening proteinuria, glycosuria and aminoaciduria despite no apparent change in eGFR. PrEP was discontinued and his urinary abnormalities rapidly resolved. The patient remains off PrEP. Conclusions Fanconi syndrome is a rare, but known complication of tenofovir disoproxil. This is the first report related to PrEP in Australia. While tenofovir associated nephrotoxicity in patients taking PrEP is uncommon, the patient’s age and pre-existing renal impairment placed him at substantially higher risk. At-risk patients need more frequent monitoring of their eGFR and proteinuria. Urinary protein to creatinine ratio is the preferred to dipstick testing for proteinuria and the latter does not readily detect the low molecular wight proteinuria characteristic of tenofovir toxicity. Early recognition of these patients is essential, as prompt cessation of PrEP can often reverse renal abnormalities.
A brain-enriched lncRNA shields cancer cells from immune-mediated killing for metastatic colonization in the brain
Authors: Liu Weiguang , Sun Peng , Xia Lingling , He Xilin , Xia Zhengmiao , Huang Yehong , Liu Wenzhuo , Li Lulu , Chen Liming
Published: May 2022

Significance

Brain metastasis with current limited treatment options is a common complication in advanced cancer patients, and breast-to-brain metastasis (B2BM) is one of the major types. In this work, we report that brain metastasis oncogenic long noncoding RNA (BMOR) is a key brain-enriched long noncoding RNA for the development of B2BM. We demonstrate that BMOR allows B2BM cells to colonize the brain tissue by evading immune-mediated killing in the brain microenvironment. At the molecular level, BMOR binds and inactivates IRF3 in B2BM cells. Finally, BMOR silencer can effectively suppress the development of brain metastasis in vivo. Therefore, our findings reveal a way in which cancer cells evade immune-mediated killing in the brain microenvironment for brain metastasis development and establish therapeutic targets with potential targeted strategies against B2BM.
Regulatory effects of gradient microtopographies on synapse formation and neurite growth in hippocampal neurons
Authors: McNaughton Ryan , Huo Yuda , Li Guicai , Di Via Ioschpe Anais , Yan Lei , Man Heng-Ye , Zhang Xin
Published: May 2022

Among approaches aiming toward functional nervous system restoration, those implementing microfabrication techniques allow the manufacture of platforms with distinct geometry where neurons can develop and be guided to form patterned connections in vitro. The interplay between neuronal development and the microenvironment, shaped by the physical limitations, remains largely unknown. Therefore, it is crucial to have an efficient way to quantify neuronal morphological changes induced by physical or contact guidance of the microenvironment. In this study, we first devise and assess a method to prepare anisotropic, gradient poly(dimethylsiloxane) micro-ridge/groove arrays featuring variable local pattern width. We then demonstrate the ability of this single substrate to simultaneously profile the morphologcial and synaptic connectivity changes of primary cultured hippocampal neurons reacting to variable physical conditons, throughout neurodevelopment, in vitro. The gradient microtopography enhanced adhesion within microgrooves, increasing soma density with decreasing pattern width. Decreasing pattern width also reduced dendritic arborization and increased preferential axon growth. Finally, decreasing pattern geometry inhibited presynaptic puncta architecture. Collectively, a method to examine structural development and connectivity in response to physical stimuli is established, and potentially provides insight into microfabricated geometries which promote neural regeneration and repair.
Determination of the partial and total pressures of the mixed gases in atomic vapor cells by optical absorption
Authors: Peng Jinpeng , Liu Zhanchao , Yin Kaifeng , Zou Sheng , Yuan Heng
Published: May 2022

We study the partial and total pressures of the mixed gases in a Rb vapor cell from its absorption spectrum under the influence of natural broadening, self-broadening, pressure broadening, the pressure shift, and Doppler broadening. A comprehensive model of the absorption coefficient on the Rb D2 line is developed, which takes into account the influence of multiple gas species. The importance of light intensity selection and frequency calibration to obtain accurate experimental results are discussed. Accurate abundances are deduced from the experimentally measured absorption spectra of vacuum cells and are used to optimize the abundance parameters in our model. We fit the experimentally measured absorption spectrum of a gas-filled cell to the optimized model and obtain a root mean square error better than 0.1%. The extracted partial pressures indicate that the mixture ratio agrees well with the designed value, while the total pressure has an increment of about 17% of its nominal value. We further estimate the amount of helium leakage in a cell to be 89.1 Torr for 6 months. Moreover, using a series of absorption spectra generated by our model as benchmarks, we evaluate the effectiveness of the commonly used single and double Lorentzian fitting models and give some suggestions for using the double Lorentzian model. This study provides a reference for designing the appropriate gas mixture for comagnetometer systems.
Generalization of deep recurrent optical flow estimation for particle-image velocimetry data
Authors: Lagemann Christian , Lagemann Kai , Mukherjee Sach , Schröder Wolfgang
Published: May 2022

Particle-image velocimetry (PIV) is one of the key techniques in modern experimental fluid mechanics to determine the velocity components of flow fields in a wide range of complex engineering problems. Current PIV processing tools are mainly handcrafted models based on cross-correlations computed across interrogation windows. Although widely used, these existing tools have a number of well-known shortcomings, including limited spatial output resolution and peak-locking biases. Recently, new approaches for PIV processing leveraging a novel neural network architecture for optical flow estimation called recurrent all-pairs field transforms (RAFT) have been developed. These have matched or exceeded the performance of classical, handcrafted models. While the RAFT-PIV method is a promising approach, it is important for the broader fluids community to more completely understand its empirical behavior and performance. To this end, in this study, we thoroughly investigate the performance of RAFT-PIV under varying image and lighting conditions. We consider applications spanning synthetic and experimental data, with a breadth and depth going far beyond currently available empirical results. The results for the wide variation of experiments shed new light on the capabilities of deep learning for PIV processing.
Collaborative detection and on-line monitoring of pipeline stress in oil and gas stations
Authors: Zhao Jianhua , Liao Kexi , Li Xiaoxiao , He Guoxi , Xia Feng , Zeng Qiang
Published: May 2022

The types of pipeline used in oil and gas stations is diverse, and it is difficult to comprehensively and accurately measure pipeline stress using a single detection method. Non-contact pipeline magnetic detection (NPMD), metal magnetic memory, ultrasonic stress measurement (USM) and ultrasonic thickness measurement (UTM)constitute a collaborative detection strategy for station pipelines. The pipeline magnetic abnormal evaluation parameter N is derived according to the sensor arrangement in NPMD devices. The magnetic field distribution based on different extraction heights is determined by the magnetic charge model and the experimental results, and a feature parameter E is constructed that can characterize the degree of stress concentration. The pipeline stress concentration points can be quickly determined in accordance with N and E. Reference stress values can be measured using USM and UTM. Monitoring is implemented at the stress concentration points, and the true stress values at the stress concentration points of the pipeline are established by combining the stress detection results. The collaborative detection method is applied to an oil and gas station, and two stress concentrations of 186.7 and 211.6 MPa are identified, respectively. The stress at the excavation pit is confirmed to be 196 MPa based on the monitoring data. Based on collaborative detection and on-line monitoring, fast and efficient collaborative detection and real-time mastering of station pipeline stress are achieved.
Pi-induced in-situ aggregation of sevelamer nanoparticles for vascular embolization
Authors: Bi Qiu-chen , Li Yan-shu , Luo Rong-guang , Chen Hong , Lv Yang-feng , Liu Zhi-Xing , Liang Qing-rong , Chen Li , Xu Bao-hua , Tang Qun
Published: May 2022

Decades have witnessed rapid progress of polymeric materials for vascular embolic or chemoembolic applications. Commercially available polymeric embolics range from gelatin foam to synthetic polymers such as poly(vinyl alcohol). Current systems under investigation include tunable, bioresorbable microspheres composed of chitosan or poly(ethylene glycol) derivatives, in situ gelling liquid embolics with improved safety profiles, and radiopaque embolics that are trackable in vivo. In this paper, we proposed a concept of ‘responsive embolization’. Sevelamer, clinically proved as an inorganic phosphate binder, was ground into nanoparticles. Sevelamer nanoparticle is highly mobile and capable of swelling and aggregating in the presence of endogenous inorganic phosphate, thereby effectively occluding blood flow in the vessel as it was administered as an embolic agent for interventional therapy. Moreover, citrated sevelamer nanoparticles delayed the aggregation, preferable to penetrate deeply into the capillary system. On the rabbit VX2 liver cancer model, both sevelamer particles aggregates occlude the tumor feeding artery, but backflow was found for the pristine one, thereby citrate passivation of sevelamer nanoparticles endows it have potential from ‘bench to bedside’ as a new type of vascular embolic.