bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Neuroendocrine Changes and Hypothalamo-Pituitary
Autoimmunity in Patients with COVID-19
Authors: Gonen Mustafa Sait , De Bellis Annamaria , Durcan Emre , Bellastella Giuseppe , Cirillo Paolo , Scappaticcio Lorenzo , Longo Miriam , Bircan Basak Ecem , Sahin Serdar , Sulu Cem , Ozkaya Hande Mefkure , Konukoglu Dildar , Kartufan Fatma Ferda , Kelestimur Fahrettin
Published: March 2022

SARS-CoV-2 may affect the hypothalamic-pituitary axis and pituitary dysfunction
may occur. Therefore, we investigated neuroendocrine changes, in particular,
secondary adrenal insufficiency, using a dynamic test and the role of
autoimmunity in pituitary dysfunction in patients with COVID-19. The
single-center, prospective, case-control study included patients with polymerase
chain reaction (PCR)-confirmed COVID-19 and healthy controls. Basal hormone
levels were measured, and the adrenocorticotropic hormone (ACTH) stimulation
test was performed. Antipituitary (APA) and antihypothalamic antibodies (AHA)
were also determined. We examined a total of 49 patients with COVID-19 and 28
healthy controls. The frequency of adrenal insufficiency in patients with
COVID-19 was found as 8.2%. Patients with COVID-19 had lower free
T3, IGF-1, and total testosterone levels, and higher cortisol and
prolactin levels when compared with controls. We also demonstrated the presence
of APA in three and AHA in one of four patients with adrenal insufficiency. In
conclusion, COVID-19 may result in adrenal insufficiency, thus routine screening
of adrenal functions in these patients is needed. Endocrine disturbances in
COVID-19 are similar to those seen in acute stressful conditions or infections.
Pituitary or hypothalamic autoimmunity may play a role in neuroendocrine
abnormalities in COVID-19.
The Combined TL-RS Approach: Advantages and Disadvantages of Working 360 Degrees around the Sigmoid Sinus
Authors: Kleijwegt Maarten , Koot Radboud , van der Mey Andel , Hensen Erik , Malessy Martijn
Published: March 2022

Objective To highlight the advantages and disadvantages of the combined translabyrinthine (TL) and classic retrosigmoid (RS) approaches.

Design Retrospective chart review.

Setting National tertiary referral center for skull base pathology.

Participants Twenty-two patients with very large cerebellopontine angle tumors were resected using the combined TL-RS approach.

Main Outcome Measures Preoperative patient characteristics including age, sex, and hearing loss. Tumor characteristics, pathology, and size. Intraoperative outcome: tumor removal. Postoperative outcomes included facial nerve function, residual tumor growth, and neurological deficits.

Results Thirteen patients had schwannoma, eight had meningioma, and one had both. The mean age was 47 years, mean tumor size was 39 × 32 × 35 mm (anterior–posterior, medial–lateral, craniocaudal), and mean follow-up period was 80 months. Tumor control was achieved in 13 patients (59%), and 9 (41%) had residual tumor growth that required additional treatment. Seventeen patients (77%) had postoperative House–Brackmann (H-B) facial nerve function grades I to II, one had H-B grade III, one H-B grade V, and three H-B grade VI.

Conclusion Combining TL and RS approaches may be helpful in safely removing large meningiomas and schwannomas in selected cases. This valuable technique should be considered when sufficient exposure cannot be achieved with the TL or RS approach alone.
Halocyclobutanol Dehydration En Route to Halocyclobutenes
Authors: Tobrman Tomáš , Oeser Petr , Petrenko Artem , Edlová Tereza , Čubiňák Marek , Koudelka Jakub
Published: March 2022

A new method for the preparation of halocyclobutenes is described. The developed process involves the dehydration of halocyclobutanols by using tetrafluoroboric acid–diethyl ether complex in dichloromethane at room temperature. The process allows for high yields of halocyclobutenes to be achieved by using alcohols that do not trigger the formation of isomeric allylic halides.
Nutrition in Asthma
Authors: Williams Evan J. , Berthon Bronwyn S. , Stoodley Isobel , Williams Lily M. , Wood Lisa G.
Published: March 2022

An emerging body of evidence suggests that diet plays an important role in both the development and management of asthma. The relationship between dietary intake and asthma risk has been explored in epidemiological studies, though intervention trials examining the effects of nutrient intake and dietary patterns on asthma management are scarce. Evidence for diets high in fruits and vegetables, antioxidants, omega-3 fatty acids and soluble fiber such as the Mediterranean diet is conflicting. However, some studies suggest that these diets may reduce the risk of asthma, particularly in young children, and could have positive effects on disease management. In contrast, a Westernized dietary pattern, high in saturated fatty acids, refined grains, and sugars may promote an inflammatory environment resulting in the onset of disease and worsening of asthma outcomes. This review will summarize the state of the evidence for the impact of whole dietary patterns, as well as individual nutrients, on the prevalence and management of asthma.
Sexual Violence Suffered by Women in Early and Late Adolescence: Care Provided and Follow-Up
Authors: Torres Alejandra Suyapa Becerra , Teixeira Ana Luiza , Côrtes Maria Teresa Ferreira , Alves Ândria Cléia , Alabarse Otávio , Azevedo Renata Cruz Soares de , Fernandes Arlete
Published: March 2022

Objective To compare the sexual violence suffered by women in early and late adolescence, the reactions triggered after the aggression, and the care provided.

Methods A retrospective study in which we reviewed the medical records of 521 female adolescents treated by a multidisciplinary team at a reference hospital in the city of Campinas, state of São Paulo, Brazil. We analyzed sociodemographic variables, and those pertainin to the characteristics of the episodes of violence, the emergency care, and the physical and psychological reactions observed during the follow-up. For the analysis, the sample was divided into groups of early (10 to 14 years) and late (15 to 18 years) adolescence. We used the Chi-squared/Fisher Exact, Mann-Whitney, and Kruskal-Wallis tests to compare the groups; the level of significance adopted was 5%.

Results The early group (n = 242) contained more adolescents who were enrolled in school (p < 0.001), suffered more daytime aggressions (p = 0.031), in their residences (p < 0.001), by an aggressor with whom they were acquainted (p < 0.001), had greater need of legal protection (p = 0.001), and took longer to seek care (p = 0.048). Feelings of guilt, shame, and the perception of violence were similar between the groups. In the late group (n = 279), there was greater consumption of alcohol during the aggression (p = 0,005); they received significantly more prophylaxis treatments; reported more physical symptoms (p = 0.033), sleep disorders (p = 0.003), symptoms of anxiety (p = 0.045), and feelings of anguish (p = 0.011); and had more prescriptions of psychotropics (p = 0.005). Only 52% completed the 6-month follow-up, with no differences between the groups.

Conclusion The age groups showed differences in the characteristics of the episodes of violence; early adolescents took longer to seek help, and the late group presented more intense symptoms and psychological worsening during the follow-up. Measures of prevention and specific care aimed at this population are needed.
Cervical Intraepithelial Neoplasia: Analyzing the Disease Present Exclusively in the Endocervical Canal
Authors: Fonseca Fernanda Villar , Cordeiro Maria Victória Gutierrez , Pozza Ariadne Cristine , Maestri Carlos Afonso
Published: March 2022

Objective To evaluate the role of cervical cytology (Pap smear) in the diagnosis of cervical intraepithelial neoplasia 2 or greater (CIN2 + ), presented exclusively in the endocervical canal, the clinical-epidemiological characteristics of this lesion, the necessary length of canal to be removed to treat, and the rate of invasive lesion hidden in the endocervical canal.

Methods Cross-sectional study, by database analysis, of patients with abnormal cytology (high-grade squamous intraepithelial lesion [HSIL]), without visible colposcopy lesion, submitted to loop electrosurgical procedure (LEEP) to evaluate the association of cytology results with the histological product of the conization, to identify the epidemiological characteristics of endocervical lesion and clinical evolution, using a p-value < 0.05 and 95% CI.

Results In 444 cases, the Pap smear sensitivity for CIN2+ diagnosis was 75% (95% CI: 69.8–79.7), specificity was 40% (95% CI: 30.2–49.5), and the prevalence rate of histological lesion was 73% (95% CI: 70.1–78.7). There was a higher prevalence of CIN2+ in women over 42 years old and invasive cancer in those over 56 years old (p < 0.001), and it was necessary to remove 2.6 cm in length of the canal to reduce the chance of recurrence (p < 0.006). The rate of invasive cancer was 2.7%.

Conclusion Cytology was related to a high prevalence to histological lesion (73%) in the diagnosis of CIN2+ in the endocervical disease; older patients presented a higher relationship with histological lesions in the canal disease, and it was necessary to remove an average of 2.6 cm in length of the endocervical canal to avoid the persistence and progression of CIN. The rate of occult neoplasia in the endocervical canal was 2.7%.
Ventrally Fused Conjoined Twins (Omphaloischiopagus): A Roadmap to Successful Separation
Authors: AbouZeid Amr A. , Mohammad Shaimaa A. , Radwan Ahmed B. , ElDieb Leila , El-Gendy Yasmin G. , Ibrahim Hanan , Amer Akram , Shabana Tarek , Elzahaby Hany , Elbarbary Amir , Saleh Mohamed , Abdelaziz Tarek H. , Elbeshry Shady , Abdel-Hay Sameh , El-Ghoneimi Alaa , Zaki Ahmad
Published: March 2022

Conjoined twining is one of the most fascinating and challenging situations which a pediatric surgeon may face in his career. Only few surgeons may have the opportunity to share in separation of such cases. In this report, we aim to share our experience with the successful separation of ventrally fused male conjoined twins (omphaloischiopagus). The case was thoroughly studied via preoperative cross-sectional imaging modalities (magnetic resonance imaging [MRI] and computed tomography [CT] angiography), complemented by data obtained from reviewing similar cases in the literature. A clear delineation of the complex anatomy was achieved preoperatively which proved to be well consistent with the operative findings. A detailed description of the operative procedure to divide/redistribute the shared abdominal/pelvic organs between both twins is provided. To the best of our knowledge, this is the first report to describe the detailed and unique internal anatomy of a common central phallus associating ischiopagus conjoined twins. The penis was centrally located in the perineum in between both twins with an open urethral plate. This common phallus had a peculiar configuration with four crura anchoring ischial bones of both twins together.
Influential Studies in Orthopaedic Platelet-Rich Plasma Research Are Recent and Consist of High Levels of Evidence: A Review of the Top 50 Most Cited Publications
Authors: Oeding Jacob F. , Lansdown Drew A. , Leucht Philipp , Bosco Joseph A. , Konopka Jaclyn , Lajam Claudette M.
Published: March 2022

Platelet-rich plasma (PRP) has garnered widespread and increasing attention in recent years. We aimed to characterize the most influential articles in PRP research while clarifying controversies surrounding its use and clinical efficacy and identifying important areas on which to focus future research efforts. The Science Citation Index Expanded subsection of the Web of Science Core Collection was systematically searched to identify the top 50 cited publications on orthopedic PRP research. Publication and study characteristics were extracted, and Spearman's correlations were calculated to assess the relationship between citation data and level of evidence. The top 50 articles were published between the years 2005 and 2016, with 68% published in the year 2010 or later. Of the 33 studies for which level of evidence was assessed, the majority were of level I or II (18, 54.5%). Seventeen articles (34%) were classified as basic science. All clinical studies were prospective, and most (12 studies, 60%) included a high number of metrics related to the PRP preparation protocol and composition. Knee osteoarthritis was the most common topic among clinical studies in the top 50 cited articles (11 studies, 34%). More recent articles were associated with higher citation rates (ρ = 0.46, p < 0.001). The most influential articles on orthopaedic PRP research are recent and consist of high–level of evidence studies mostly. Randomized controlled trials were the most common study type, while basic science articles were relatively less common. The most influential clinical studies reported a high number of metrics related to their PRP preparation protocol and the final PRP composition. These results suggest a rapidly evolving field with the potential to better explain inconsistent clinical results with improved understanding and documentation of basic science concepts such as PRP composition, preparation, and combination techniques.
Agro-sphere determinants of green branding: eco-consumption, loyalty, and price premium
Authors: Danko Yuriy , Nifatova Olena
Published: March 2022

This research is devoted to the determinants of green branding in the agro-sphere. The existence of competition between regular and green brands in the agricultural sector has necessitated the determination of the degree of influence of green branding on the formation of consumer loyalty in order to understand the effectiveness and feasibility of such practices among agricultural producers. Previous research in the study of green branding has not focused on the factors studied influencing the level of consumption of organic products or the factors influencing the size of the price premium for green brands. In this study, the influence of green branding on the loyalty of consumers of the eco-market was determined on the basis of a comparison of integrated indicators of satisfaction and importance of the regular brand and green brands by an expert survey of 250 respondents in five supermarkets in Kyiv (Ukraine). In the example comparing the coefficients of consumer loyalty of eggs of the eco-brand and the regular brand, it was found that the rate of consumer loyalty to the eco-brand exceeded the rate of consumer loyalty to the regular brand by 3%. It was established that the size of the price premium of a green brand is determined by such factors as consumer loyalty, availability of organic certificates, costs of green advertising, additional cost of organic products, average profitability of the industry, and average income of consumers. Based on cluster and discriminant analysis, green brands were divided into three levels of price premium: “high”, “medium”, and “low.” Discriminant equations for each cluster according to the level of price premium were constructed. Such equations make it possible to assign a new object of analysis (a new brand) to a certain classificational price category. The current study proves the feasibility and economic and statistical validity of the impact of green branding on consumer loyalty in the agricultural sector. The study has significant implications for brand management by providing empirical evidence that can improve brand managers’ strategic decisions in determining the level of price premium.
Equitable group work increases physics interest, belief in abilities
Authors: Piccone Ashley
Published: March 2022

Students who participate in each part of an experiment benefit more than students who split up work by task
A prototype portable instrument employing micro-preconcentrator and FBAR sensor for the detection of chemical warfare agents
Authors: Yan Xu , Qu Hemi , Chang Ye , Pang Wei , Duan Xuexin
Published: March 2022

The presence of chemical warfare agents (CWAs) in the environment is a serious threat to human safety, but there are many problems with the currently available detection methods for CWAs. For example, gas chromatography–mass spectrometry cannot be used for in-field detection owing to the rather large size of the equipment required, while commercial sensors have the disadvantages of low sensitivity and poor selectivity. Here, we develop a portable gas sensing instrument for CWA detection that consists of a MEMS-fabricated micro-preconcentrator (μPC) and a film bulk acoustic resonator (FBAR) gas sensor. The μPC is coated with a nanoporous metal–organic framework material to enrich the target, while the FBAR provides rapid detection without the need for extra carrier gas. Dimethyl methylphosphonate (DMMP), a simulant of the chemical warfare agent sarin, is used to test the performance of the instrument. Experimental results show that the μPC provides effective sample pretreatment, while the FBAR gas sensor has good sensitivity to DMMP vapor. The combination of μPC and FBAR in one instrument gives full play to their respective advantages, reducing the limit of detection of the analyte. Moreover, both the μPC and the FBAR are fabricated using a CMOS-compatible approach, and the prototype instrument is compact in size with high portability and thus has potential for application to in-field detection of CWAs.
Suitability of metallic materials for constructing metal-coated dielectric terahertz waveguides
Authors: Huang Yuyuan , Konishi Kuniaki , Deura Momoko , Shimoyama Yusuke , Yumoto Junji , Kuwata-Gonokami Makoto , Shimogaki Yukihiro , Momose Takeshi
Published: March 2022

We aimed to identify metallic materials that could be used to construct metal-coated dielectric terahertz (THz) waveguides. We examined seven different metals: gold (Au), copper (Cu), silver (Ag), aluminum (Al), nickel (Ni), chromium (Cr), and titanium (Ti). The propagation losses of our in-house metal-coated dielectric parallel-plate waveguide (PPWG) were experimentally determined. We developed a physical model to estimate the two key parameters determining the performance of metal-coated waveguides: the critical film thickness required for bulk material-like behavior and the propagation loss in a film with a thickness greater than critical film thickness. Film quality, as revealed by the thickness-dependent electrical conductivity of the metal film, was measured prior to experiments and used for model calculations because propagation loss is influenced by film conductivity, which differs from bulk conductivity and depends on film thickness. After experimentally validating the applicability of the model to different metals, suitable metals were identified based on the two key parameters calculated by the model, assuming the same high film quality. Cu was identified as the optimal metal. The effect of film quality on the two key parameters is discussed in this paper. The impact of the surface oxide (CuOx) layer on THz wave propagation was experimentally evaluated using CuOx/Cu-coated PPWG; no detectable transmittance decrease was observed regardless of the CuOx thickness (1.5–176 nm), when the underlying Cu film was of sufficient thickness. Our model also indicated that a CuOx layer <1 μm-thick had a negligible impact on THz wave propagation. Thus, native oxidation is not an issue when using Cu.
Resonant electron capture by 5-Br-2′-deoxyuridine
Authors: Shchukin P. V. , Muftakhov M. V. , Khatymov R. V. , Tuktarov R. F.
Published: March 2022

The results of the study of resonant electron capture by molecules of 5-Br-2′-deoxyuridine (BrdUrd) over the range of electron energies from near zero to 14 eV are described. In the thermal energy range, long-lived molecular negative ions, unstable with respect to autoneutralization and dehalogenation, have been registered. Examination of the kinetics of these decay processes led us to the conclusion that the most probable structure for molecular negative ions is that with an extended C–Br bond, which was predicted earlier using quantum-chemical calculations. Estimates have shown that the BrdUrd molecule owns a significant electronic affinity of 0.93–1.38 eV. The most intense fragmentation channel leads to the abundant formation of Br− ions. The dissociative electron attachment cross section for Br− ions formation was estimated to amount to no less than 1.65 × 10−15 cm2, indirectly implying a fairly intense formation of complementary highly reactive deoxyuridine-5-yl particles. These particles are known to be responsible for the radiosensitizing properties of BrdUrd.
Modeling diffusion length damage coefficient in GaAs and InGaP solar cells under electron irradiation
Authors: Bisht P.
Published: March 2022

A method is proposed for calculating the diffusion length damage coefficient for minority carriers (KL) in GaAs and InGaP solar cells under electron irradiation using the Shockley–Read–Hall (SRH) model for defect-assisted recombination. In the SRH model, the damage coefficient KL is proportional to the product kσc, where k is the defect introduction rate under particle radiation and σc is the minority carrier capture cross section of the said defects. The introduction rate k is evaluated using the atomic theory for displacement under electron radiation, and the calculation for σc is adapted from Henry and Lang’s high-temperature multiphonon emission formulation. A linear scaling relationship is observed between k,KL and nonionizing energy loss—validated by bibliographic data in the radiation energy range E≈0.7–12 MeV. Our model reproduces the increasing trend in KL with doping, as observed in the literature, while also capturing the anisotropy between the p-type and n-type materials, with the p-type exhibiting greater radiation resistance than its n-type counterpart. The calculated KL is fed into the physical model for solar cell operation to obtain the post-irradiated Isc,Voc,Pmax at a given fluence Φ. The degradation of the electrical quantities is consistent with the measurements recorded in the literature. The findings show that InGaP is more radiation resistant than GaAs. It is demonstrated that calculating k not only aids in determining the degradation of solar cell parameters from first principles, but also in obtaining the empirical function for degradation: a−blog(1+ckΦ), used in fitting the experimental measurements. The limitations and potential scope of improvements in the model are also discussed.
Design optimization and off-design performance analysis of axisymmetric scramjet intakes for ascent flight
Authors: Brahmachary Shuvayan , Fujio Chihiro , Aksay Mehmet , Ogawa Hideaki
Published: March 2022

Scramjet engines are one of the most economical and reliable high-speed airbreathing propulsion technologies that can be used for low-cost satellite launchers and hypersonic atmospheric transportation. For access to space, the flight envelope practically comprises varying freestream conditions and altitude during ascent flight, constituting a complex optimization problem subject to various constraints from design and operation perspectives. This paper presents the results and insights obtained from a multi-objective optimization study of three classes of axisymmetric scramjet intakes, i.e., three-ramp, Busemann-based, and generic intakes represented by smooth Bézier curves, with the same intake mass flow rate for all classes. Optimization is conducted by means of surrogate-assisted evolutionary algorithms coupled with computational fluid dynamics simulations using a Reynolds-averaged Navier–Stokes flow solver for steady-state flowfields. It aims to minimize the intake drag and maximize the compression efficiency at Mach 7.7 at an altitude of 30 km simultaneously. It has been found that generic intakes, which offer greater local shape control, can achieve the highest compression efficiency of 94.8%, the highest total pressure recovery, and the highest flow uniformity at the intake exit. The Busemann-based intakes, on the other hand, can produce the highest static pressure ratio while incurring the lowest drag force. The utility of principal component analysis has effectively reduced the dimensions of the solutions, and has identified clusters of non-dominated solutions according to their characteristics such as geometric attributes, exit flow profiles, and wall property distributions, thereby conducing to obtain further physical insights into the optimal configurations.
Using maximum likelihood estimation approach to adjust parameters of multiphase equations of state: Molybdenum as an example
Authors: Robert G. , Dubois V. , Legrand P.
Published: March 2022

We present a promising systematic and quite automated approach for constructing multiphase equation of state (EOS). The maximum-likelihood-estimation, a well-known statistical tool, is applied to tune the EOS model parameters to better agree with a calibration database. To perform that, we use POOH, a newly developed code for constructing sophisticated EOS. The calibration database is made up of a variety of experimental measurements and theoretical data. As statistics is involved, one crucial point is to create a calibration database including error bars. The error bars are routinely defined when experimental data are involved. We discuss how we have introduced this notion for theoretical calculations. Focusing on molybdenum, the calibration database includes isobaric data, isothermal data, density functional theory-calculations of the melt curve, liquid isotherms, and the critical point. We demonstrate the capability of our methodology to adjust model parameters, creating a reliable multiphase EOS POOH_Mo_21 that fits accurately our calibration database and data not previously considered such as principal and porous Hugoniot.
Nitrogen plasma passivated niobium resonators for superconducting quantum circuits
Authors: Zheng K. , Kowsari D. , Thobaben N. J. , Du X. , Song X. , Ran S. , Henriksen E. A. , Wisbey D. S. , Murch K. W.
Published: March 2022

Microwave loss in niobium metallic structures used for superconducting quantum circuits is limited by a native surface oxide layer formed over a timescale of minutes when exposed to an ambient environment. In this work, we show that nitrogen plasma treatment forms a niobium nitride layer at the metal–air interface, which prevents such oxidation. X-ray photoelectron spectroscopy confirms the doping of nitrogen more than 5 nm into the surface and a suppressed oxygen presence. This passivation remains stable after aging for 15 days in an ambient environment. Cryogenic microwave characterization shows an average filling-factor-adjusted two-level-system loss tangent FδTLS of (2.9±0.5)·10−7 for resonators with a 3 μm center strip and (1.0±0.3)·10−7 for a 20 μm center strip, exceeding the performance of unpassivated samples by a factor of four.
Experimental study on the micro-explosion characteristics of two blended types of droplets under different nitrogen flow rates
Authors: Han Kai , Lin Qizhao , Liu Minghou , Meng Kesheng , Ni Zhanshi , Liu Yu , Tian Junjian
Published: March 2022

Using the single droplet suspension method, the effect of nitrogen flow rate on the micro-explosion characteristics of L/H (low-boiling fuel in high one) and H/L (high-boiling fuel in low one) droplets in the laminar flow regime at 700 °C and atmospheric pressure was studied. The experimental results showed that for B80P20 (80% biodiesel and 20% 1-pentanol by volume) and B20P80 (20% biodiesel and 80% 1-pentanol), the micro-explosion intensity as well as the number of micro-explosions and strong micro-explosions increased first and then decreased with the increase in the nitrogen flow rate. In addition, the change range of B20P80 was always larger than that of B80P20. The micro-explosion intensity of B80M20 (80% biodiesel, 20% methanol) changed a little. However, for B20M80 (20% biodiesel, 80% methanol), it decreased monotonously with nitrogen flow rate. The variation of droplet lifetime was opposite to that of micro-explosion intensity except for B80M20. The micro-explosion delay time and relative micro-explosion delay time increased monotonously with nitrogen flow rate for B80P20, B20P80, and B20M80. As nitrogen flow rate increased, the micro-explosion distribution of B80M20 and B20M80 became more dense, but for B80P20 and B20P80, it became dense first and then sparse. In short, the nitrogen flow rate had a greater impact on H/L droplets than L/H ones, and a greater impact on B20M80 than B20P80. The experimental results provided a reference for further study on the micro-explosion mechanism of different blended types of droplets in different flow regimes.
Heat transfer characteristics of plasma actuation in different boundary-layer flows
Authors: Hui Weiwei , Zhang Hexiang , Wang Jianlei , Meng Xuanshi , Li Huaxing
Published: March 2022

The coupling characteristics of the aerodynamic and thermal effects of a surface dielectric barrier discharge plasma actuator and its transfer characteristics in different boundary-layer flows are studied experimentally. The actuator is attached to the surface of a flat-plate airfoil and driving by an alternative-current signal. Different boundary-layer flows are achieved in the wind tunnel by adjusting the airfoil's angle of attack with a Reynolds number of 2.02 × 105. The spatial temperature-rise distributions and velocity fields induced by plasma actuation in quiescent air show that the influence range of temperature is consistent with that of the induced velocity field. The aerodynamic and thermal effects induced by plasma actuation have strong coupling characteristics. The heat around the actuator is limited within the boundary-layer flows with a 15 m/s incoming flow. The temperature rise outside the boundary layer is close to zero. In the turbulent boundary-layer flow, the temperature is lower than that in the laminar boundary-layer flow as a whole. The maximum temperature-rise difference exceeds 10 °C. In the leading-edge separation-bubble flow, most heat generated by the plasma actuation is restricted inside the separation bubble. The results provide references for the mechanism detection of related plasma icing-control and flow-control research.
Optically pumped deep-UV multimode lasing in AlGaN double heterostructure grown by molecular beam homoepitaxy
Authors: van Deurzen Len , Page Ryan , Protasenko Vladimir , Nomoto Kazuki , Xing Huili (Grace) , Jena Debdeep
Published: March 2022

Multimode lasing at sub-300 nm wavelengths is demonstrated by optical pumping in AlGaN heterostructures grown on single-crystal AlN substrates by plasma-assisted molecular beam epitaxy. Edge-emitting ridge-based Fabry–Pérot cavities are fabricated with the epitaxial AlN/AlGaN double heterostructure by a combined inductively coupled plasma reactive ion etch and tetramethylammonium hydroxide etch. The emitters exhibit peak gain at 284 nm and modal linewidths on the order of 0.1 nm at room temperature. The applied growth technique and its chemical and heterostructural design characteristics offer certain unique capabilities toward further development of electrically injected AlGaN laser diodes.
Simultaneous measurement for amplitude and frequency of time-harmonic force based on optomechanically induced nonlinearity
Authors: Zhao Daiyue , Liu Shaopeng , Wang Junfeng , Mao Yaya , Li Ying , Liu Bo
Published: March 2022

An accurate readout of the mechanical motion using optomechanical coupling is highly desired for on-chip sensing applications but it remains challenging due to the uncertainty caused by time-dependent parameters and noisy fluctuations. Here, we propose an efficient scheme to realize simultaneous measurement for both amplitude and frequency of the time-harmonic force (THF) in a hybrid optomechanical system via a nonlinear sum sideband effect. In this optomechanical system assisted by a degenerate parametric amplifier (DPA), the nonlinear optomechanical interaction between the external THF, optical, and mechanical modes is used to construct the frequency component of optical sum sidebands. Using experimentally achievable parameters, we find that the conversion efficiency of the sum sidebands has a significant enhancement when the nonlinear gain coefficient of DPA increases. In the scheme of the dual-parameter measurement, we also report that the amplitude of THF could be independently detected by observing the intensity variation of the lower sum sideband, while the frequency of THF could be separately read by monitoring the frequency of the prominent peak in this nonlinear spectrum. Benefitting from the optical cooling of a mechanical element, the theoretical results show that the minimum resolutions for detecting the amplitude and the frequency of THF are approximately 8.8×10−12N and 16Hz, respectively.
Achieving superconductivity with higher Tc in lightweight Al–Ti–Mg alloys: Prediction using machine learning and synthesis via high-pressure torsion process
Authors: Mito Masaki , Mokutani Narimichi , Tsuji Hiroki , Tang Yongpeng , Matsumoto Kaname , Murayama Mitsuhiro , Horita Zenji
Published: March 2022

Aluminum (Al) and titanium (Ti) are superconducting materials but their superconducting transition temperatures (Tc) are quite low as 1.20 and 0.39 K, respectively, while magnesium (Mg) never exhibits superconductivity. In this study, we explored new superconductors with higher Tc in the Al–Mg–Ti ternary system, along with the prediction using machine learning. High-pressure torsion (HPT) is utilized to produce the superconducting states. While performing AC magnetization measurements, we found, for the first time, superconducting states with Tc=4.0 and 7.3 K for a composition of Al:Ti = 1:2. The magnetic anomalies appeared more sharply when the sample was processed by HPT at 573 K than at room temperature, and the anomalies exhibited DC magnetic field dependence characteristic of superconductivity. Magnetic anomalies also appeared at ∼55 and ∼93 K, being supported by the prediction using the machine learning for the Al–Ti–O system, and this suggests that Al–Ti oxides play an important role in the advent of such anomalies but that the addition of Mg could be less effective.
Magnetization plateau of the distorted diamond spin chain with anisotropic ferromagnetic interaction
Authors: Sakai Tôru , Okamoto Kiyomi , Nakano Hiroki , Furuchi Rito
Published: March 2022

The S = 1/2 distorted diamond spin chain with the anisotropic ferromagnetic interaction is investigated using the numerical diagonalization and the level spectroscopy analysis. It is known that the system exhibits a plateau of the magnetization curve at the 1/3 of the saturation. The present study indicates that as the anisotropy is varied the quantum phase transition occurs between two different mechanisms of the 1/3 magnetization plateau. The phase diagram with respect to the anisotropy and the ferromagnetic coupling is also presented.
Experimental study of emergent ground state behavior in Gd1-xCexNi5 (x = 0; 0.2; 0.5; 0.8 and 1) melt-spun ribbons
Authors: Dzubinska Andrea , Fernández Jesús Rodriguez , Reiffers Marian , Espeso Jose Ignacio , Varga Rastislav , Arun K. , Goméz Sal Jose Carlos
Published: March 2022

The ground state physical properties of Gd1-xCexNi5 (x = 0; 0.2; 0.5; 0.8 and 1) melt-spun ribbons were investigated by X-ray diffraction, magnetization and specific heat measurements. The produced ribbon samples are single phases with the hexagonal CaCu5-type crystal structure. The magnetic transition temperature decreases with increasing Ce content. At a temperature around 100 K for the CeNi5 melt-spun ribbon, the spin fluctuations effect is visible.
Effect of Joule heating on GMI and magnetic properties of Fe-rich glass-coated microwires
Authors: Gonzalez A. , Zhukova V. , Ipatov M. , Corte-Leon P. , Blanco J. M. , Zhukov A.
Published: March 2022

Influence of Joule heating on magnetic properties and GMI effect of Fe75B9Si12C4 glass-coated microwires was studied. A decrease in coercivity after Joule heating is observed, while hysteresis loops of Joule heated samples maintain a rectangular shape. However, a remarkable increase in GMI ratio is observed in Joule heated samples. Observed GMI ratio improvement has been discussed considering magnetic anisotropy induced by Oersted magnetic field during Joule heating and internal stress relaxation. A remarkable GMI effect improvement observed in Joule heated Fe-rich microwires, along the fact that Fe is a more common, less expensive metal than Co, makes them suitable for magnetic sensor applications.
Seebeck coefficient of Cr100−zOsz alloy system
Authors: Fernando P. R. , Prinsloo A. R. E. , Sheppard C. J.
Published: March 2022

The magnetic phase diagram of the Cr100−zOsz alloy system exhibits possible quantum critical behavior (QCB), with commensurate spin-density-wave to paramagnetic (CSDW-PM) phase line terminating at z ≈ 14, in a superconducting dome at z ≈ 12. Also indicated is the co-existence of SDW antiferromagnetism (AFM) and superconductivity (SC) for the z = 12.2 sample with a bcc structure. Considering the unique behaviour in the Cr100−zOsz system, this study reports on an investigation into the temperature dependence of the thermoelectric power or Seebeck coefficient, ST. With S(T) sensitive to the electronic structure and scattering mechanisms it is used here in order to investigate the unique magnetic behaviour observed in this alloy. ST measurements were performed on polycrystalline Cr100−zOsz (2.1 ≤ z ≤ 14.1) samples, as confirmed by XRD to be in a single bcc phase. The low-temperature S(T) behaviour is expressed in the form S = aT + bT3, where a and b are constants that were determined to discuss the possible contributions of phonon and/or magnon drag to S. Resulting a(z) and b(z) behaviour indicate anomalies that can be associated with three crucial points in the Cr100−zOsz magnetic phase diagram: (i) at z ≈ 8 is associated with the destabilization of the CSDW phase with the continual addition of Os into the system, (ii) at z ≈ 12 where the SC properties manifest and (iii) at z ≈ 13 associated with quantum critical behaviour this the system. Considering dS/dT where T approaches 0 K, as function of z, clear anomalies are observed at z ≈ 12 and 13, which, are associated with the onset of SC and QCB in this system. The present results suggest that S is a decisive experimental parameter in characterizing anomalous behaviour reflected in the magnetic phase diagram of Cr100−zOsz.
Interface-driven spin pumping and inverse Rashba-Edelstein effect in FeGaB/Ag/BiSb multilayers
Authors: Sharma Vinay , Bajracharya Prabesh , Johnson Anthony , Budhani Ramesh C.
Published: March 2022

Spin-orbit-coupling (SOC) plays a critical role in spin-to-charge conversion (SCC) mechanism. The SCC process is usually investigated by injecting a spin current from ferromagnet (FM) into a large SOC normal metal (SOC-NM) and then measuring the voltage generated by inverse spin Hall effect (ISHE). Recently, a new mechanism of SCC at inversion symmetry breaking interfaces between topological insulators (TIs) and magnetically ordered materials has been introduced, which is driven by the inverse Rashba-Edelstein effect (IREE). Motivated by this result, we have investigated the IREE effect of a simple binary three-dimensional TI Bi85Sb15 (BiSb). The model system used here is a trilayer of FeGaB/Ag/BiSb with different Ag thickness made insitu with a combination of dc magnetron sputtering and pulsed laser ablation. The SCC efficiency has been evaluated by measuring ferromagnetic resonance (FMR) driven ISHE voltage and extraction of the Gilbert damping (α) and interfacial spin mixing conductance (g↑↓) from the FMR line shape analysis. It is interesting to note that the charge current (Ic) increases with Ag thickness. This observation indicated that the IREE process at the Ag/BiSb interface dominates over ISHE in the bulk of BiSb film. The conversion efficiency of IREE is determined by calculating the IREE length (λIREE), which increases with the thickness of the Ag layer. These findings offer a method to generate and detect the IREE in a room temperature deposited heterostructure using simple coplanar waveguide setup.
Temperature dependent magnetostatic and dynamic properties of soft magnetic FeGaB/Al2O3 thin films for microwave applications
Authors: Wang Yuxi , Yadagiri Karampuri , Wu Peng , Wu Tao
Published: March 2022

Iron Gallium Boron (FeGaB) thin film is one of the low-loss self-biased soft magnetic films. In this report, the temperature dependent magnetostatic and dynamic properties of FeGaB/Al2O3 composite soft magnetic thin films were studied. The analysis of surface roughness, crystal orientation and magnetostatic properties indicate that the grain size and anisotropy of the thin film increase after annealing which temperature is from 573 K to 773 K. The ferromagnetic resonance spectra of different annealed thin films suggest the damping factor, linewidth and resonance magnetic fields all increase with the increased annealing temperature, which is attributed to the change of film crystallization. Moreover, the angle dependent anisotropic magnetoresistance and planar Hall effect show the percentage of magnetoresistance change increased due to the high annealing temperature.
Synthesis of Catalyst-Free Carbon Nano Onions (CNOs) for Advanced Functional Materials
Authors: Kharwar Prakhar Kumar , Verma Rajesh Kumar , Debnath Kishore , Singh Abhishek
Published: March 2022

Recent investigations in the development of nanomaterials show their compatibility with micro/macrocomposites. A little accumulation of nanomaterials in the matrix can boost the strength and other mechanical features prominently. Carbon nano-onions (CNOs) have become a suitable alternative as a participating fiber in polymer composites. It can maintain a uniform distribution and a higher aspect ratio even after insertion into the matrix due to its nanoscopic form. CNO nanocomposites are used in the fabrication of biomedical sensors, microelectronic and optical devices, light wave communication systems, etc. The 0D (zero-dimensional) CNOs are efficiently synthesized at low temperatures from wax (hydrocarbon source). This present methodology does not require any catalyst or pre-treatment with toxic chemicals. The use of an inexpensive biosource and a readily available hydrocarbon source with a simple domestic arrangement for the synthesis of 0D CNOs are presented. This chapter explains the essential details on the catalyst-free synthesis and functionalization of CNOs. Also, it aims to showcase the CNO's potential as a reinforcement agent in the epoxy matrix, which may improve its desirable material properties significantly. All this is possible by using a very low-cost fabrication methodology by a simple flame synthesis of hydrocarbon sources.
RemodelingYersinia pseudotuberculosisto generate a highly immunogenic outer membrane vesicle vaccine against pneumonic plague
Authors: Wang Xiuran , Li Peng , Singh Amit K. , Zhang Xiangmin , Guan Ziqiang , Curtiss Roy , Sun Wei
Published: March 2022

Significance

Yersinia pestis, the etiologic agent of plague, has been responsible for high mortality in several epidemics throughout human history. This plague bacillus has been used as a biological weapon during human history and is currently one of the deadliest biological threats. Currently, no licensed plague vaccines are available in the Western world. Since an array of immunogens are enclosed in outer membrane vesicles (OMVs), immune responses elicited by OMVs against a diverse range of antigens may reduce the likelihood of antigen circumvention. Therefore, self-adjuvanting OMVs from a remodeledYersinia pseudotuberculosisstrain as a type of plague vaccine could diversify prophylactic choices and solve current vaccine limitations.
Bayesian modeling of human–AI complementarity
Authors: Steyvers Mark , Tejeda Heliodoro , Kerrigan Gavin , Smyth Padhraic
Published: March 2022

Significance

With the increase in artificial intelligence in real-world applications, there is interest in building hybrid systems that take both human and machine predictions into account. Previous work has shown the benefits of separately combining the predictions of diverse machine classifiers or groups of people. Using a Bayesian modeling framework, we extend these results by systematically investigating the factors that influence the performance of hybrid combinations of human and machine classifiers while taking into account the unique ways human and algorithmic confidence is expressed.
Particle-based hematite crystallization is invariant to initial particle morphology
Authors: Wang Yining , Xue Sichuang , Lin Qingyun , Song Duo , He Yang , Liu Lili , Zhou Jianbin , Zong Meirong , De Yoreo James J. , Zhu Junwu , Rosso Kevin M. , Sushko Maria L. , Zhang Xin
Published: March 2022

Significance

Many crystallization processes occurring in nature produce highly ordered hierarchical architectures. Their formation cannot be explained using classical models of monomer-by-monomer growth. One of the possible pathways involves crystallization through the attachment of oriented nanocrystals. Thus, it requires detailed understanding of the mechanism of particle dynamics that leads to their precise crystallographic alignment along specific faces. In this study, we discover a particle-morphology–independent oriented attachment mechanism for hematite nanocrystals. Independent of crystal morphology, particles always align along the [001] direction driven by aligning interactions between (001) faces and repulsive interactions between other pairs of hematite faces. These results highlight that strong face specificity along one crystallographic direction can render oriented attachment to be independent of initial particle morphology.
Symmetry and simplicity spontaneously emerge from the algorithmic nature of evolution
Authors: Johnston Iain G. , Dingle Kamaludin , Greenbury Sam F. , Camargo Chico Q. , Doye Jonathan P. K. , Ahnert Sebastian E. , Louis Ard A.
Published: March 2022

Significance

Why does evolution favor symmetric structures when they only represent a minute subset of all possible forms? Just as monkeys randomly typing into a computer language will preferentially produce outputs that can be generated by shorter algorithms, so the coding theorem from algorithmic information theory predicts that random mutations, when decoded by the process of development, preferentially produce phenotypes with shorter algorithmic descriptions. Since symmetric structures need less information to encode, they are much more likely to appear as potential variation. Combined with an arrival-of-the-frequent mechanism, this algorithmic bias predicts a much higher prevalence of low-complexity (high-symmetry) phenotypes than follows from natural selection alone and also explains patterns observed in protein complexes, RNA secondary structures, and a gene regulatory network.
Tsc2 knockout counteracts ubiquitin-proteasome system insufficiency and delays photoreceptor loss in retinitis pigmentosa
Authors: Wang Yixiao , Punzo Claudio , Ash John D. , Lobanova Ekaterina S.
Published: March 2022

Significance

Studies in multiple experimental systems have demonstrated that an increase in proteolytic capacity of post-mitotic cells improves cellular resistance to a variety of stressors, delays cellular aging and senescence. Therefore, approaches to increase the ability of cells to degrade misfolded proteins could potentially be applied to the treatment of a broad spectrum of human disorders. An example would be retinal degenerations, which cause irreversible loss of vision and are linked to impaired protein degradation. This study suggests that chronic activation of the mammalian target of rapamycin complex 1 (mTORC1) pathway in degenerating photoreceptor neurons could stimulate the degradation of ubiquitinated proteins and enhance proteasomal activity through phosphorylation.