bluuebunny/crossref_metadata_2025 huggingface dataset:
Psychologische Strategien der Bewegungstherapie in der stationären, orthopädischen Rehabilitation – Ein-Gruppen Prä-Post-Evaluation einer Fortbildung für Bewegungstherapeut*innen
Authors: Göhner Wiebke , Schagg Daniela , Küffner Roland , Reusch Andrea
Published: October 2021

Körperliche Aktivität verbessert Erkrankungsverläufe und hat daher in der stationären orthopädischen Rehabilitation einen hohen Stellenwert. Personen mit muskuloskelettalen Erkrankungen fällt es jedoch oft schwer, auch im Alltag aktiv zu bleiben. Um die langfristige Bewegungsaktivität im Alltag zu unterstützen, sollte die Bewegungstherapie verhaltensbezogen erfolgen 10. Dazu können psychologische Strategien der Verhaltensänderung eingesetzt werden (im Folgenden: Strategien der Bewegungsförderung). Da Bewegungstherapeut*innen (BT) den Transfer von Bewegungsaktivität in den Alltag unterstützen, sollten sie über Wissen und Kompetenzen verfügen, um wirksame verhaltensbezogene Strategien der Bewegungsförderung zielgerichtet und präzise einzusetzen. Bislang wurde selten systematisch evaluiert, wie die Wissensvermittlung und Kompetenzförderung zur verhaltensbezogenen Bewegungstherapie und zur Nutzung dieser Strategien in Fortbildungen gelingen kann. Ziel eines Projekts war deshalb die Entwicklung und Evaluation einer Fortbildung. Über die Entwicklung als Inhouse-Workshop mit 2 alternativen Vertiefungsformaten (arbeitsbegleitend vs. Workshop) wurde andernorts berichtet 19. Mit der Evaluation sollte geprüft werden, ob durch die Fortbildung Wissen und Kompetenzen verbessert werden können und ob die BT die vermittelten Strategien anwenden. 51 BT aus 4 stationären Reha-Einrichtungen, die Personen mit muskuloskelettalen Erkrankungen behandeln, erklärten sich bereit, an der Studie teilzunehmen. Sie nahmen an der Fortbildung teil und erhielten zu 4 Messzeitpunkten Fragebögen: direkt vor und 2 Wochen nach der Fortbildung (T1, T2), nach den Vertiefungsformaten (T3; 5–6 Monate nach der Fortbildung) sowie 8–9 Monate nach der Fortbildung (T4). In die Analysen eingeschlossen wurden 28 BT, die an der Inhouse-Fortbildung und einem der Vertiefungsformate teilgenommen hatten sowie alle 4 Fragebögen ausgefüllt hatten. Primäre Zielgrößen waren Wissen und Kompetenzen zu Strategien der Bewegungsförderung, sekundäre Zielgrößen betrafen die Implementierung dieser Strategien in der eigenen bewegungstherapeutischen Arbeit. Außerdem wurden Unterschiede zwischen den beiden Vertiefungsformaten beschrieben. Die BT gaben nach den Inhouse-Fortbildungen (T2) signifikant höhere Werte für Wissen, theoretisches Verständnis und selbsteingeschätzte Kompetenzen zu den Strategien der Bewegungsförderung an als zu T1. Diese Werte stabilisierten sich bis zum letzten Messzeitpunkt (T4). Auch die Absicht, Strategien einzusetzen und die Häufigkeit des Einsatzes der Strategien steigerten sich signifikant. Bei den Vertiefungsformaten ergaben sich deskriptiv deutlich bessere Werte für den Workshop gegenüber den individuellen, arbeitsbegleitenden Einheiten.
peb unterstützt europäische Kindergarantie
Authors: Kranz Julia
Published: October 2021

Die Plattform und Ernährung e. V. (peb) hat am 31. Mai 2021 gemeinsam mit der Arbeitsgemeinschaft der deutschen Familienorganisationen (AGF) ein digitales Fachgespräch zur europäischen „Kindergarantie“ ausgerichtet.
Körperliche Aktivität von Menschen mit geistiger Behinderung: Ergebnisse qualitativer Nutzerinterviews und Implikationen für zielgruppenspezifische Konzepte
Authors: Mauro Antonia , Bayo Laura Herrera , Bruland Dirk , Latteck Änne-Dörte
Published: October 2021

Obwohl Menschen mit geistiger Behinderung ein vergleichsweise geringes körperliches Aktivitätsniveau aufweisen, sind zielgruppenspezifische Interventionen und Konzepte, die eine nachhaltige bewegungsbezogene Verhaltensänderung durch Stärkung bewegungsbezogener Kompetenzen anstreben, selten. Durch (systematische) Literaturrecherchen wurde angestrebt, wissenschaftlich verlässliche Aussagen zu wirksamen bewegungsfördernden Interventionen zu treffen. Bestehende Interventionen sind sehr heterogen, was dadurch nur mit hohen Einschränkungen gelang. Weiterhin wurde die Perspektive der Zielgruppe bislang kaum und somit unzureichend berücksichtigt.

Über 24 qualitative Interviews mit Menschen mit geistiger Behinderung wurden anhand eines partizipativ entwickelten Leitfadens individuelle bewegungsbezogene Wissensbestände und Erfahrungen, Strategien im Umgang mit körperlicher Aktivität und Wünsche an ein bewegungsförderndes Konzept erkundet. Individuelle und kontextuelle Einflüsse auf ein körperlich aktives Verhalten wurden identifiziert. Die Interviewergebnisse wurden genutzt, um Implikationen für die Konzeption von bewegungsfördernden Interventionen abzuleiten.

Als besonders charakteristisch für die Bevölkerungsgruppe stellten sich die sehr heterogenen kognitiven und körperlichen Fähigkeiten und die lebensweltlichen strukturellen Rahmenbedingungen dar. Es wird angenommen, dass insbesondere solche Konzepte die besonderen Eigenschaften der Zielgruppe adressieren können, welche sich flexibel an deren unterschiedliche Bedürfnisse und Fähigkeiten anpassen können. Zudem scheinen eine Förderung von selbstregulativen Kompetenzen im Umgang mit körperlicher Aktivität und das Ermöglichen eines niedrigschwelligen Zugangs zu körperlicher Aktivität zielführend.
First Total Synthesis of the Marine-Derived Anti-inflammatory Natural Product (–)-Herdmanine D through a Steglich Esterification
Authors: Bhagat Sunita , Sharma Pankaj , Sharma Nutan , Kashyap Gunjan
Published: October 2021

An efficient and regioselective route for the first total synthesis of the antiinflammatory marine natural product (–)-herdmanine D, with an excellent overall yield of 18%, is described. A key feature of the synthetic strategy is a Steglich esterification of regioselectively constructed 6-bromo-5-methoxy-1H-indole-3-carboxylic acid with protected l-tyrosine. The formation of the l-isomer was confirmed through measurement of the optical activity. The current strategy paves the way for the construction of diverse analogues of (–)-herdmanine D for drug development.
Countering COVID-19 Vaccine Hesitancy in Pregnancy: the “4 Cs”
Authors: Shook Lydia L. , Kishkovich Thomas P. , Edlow Andrea G.
Published: October 2021

Despite evidence to support the safety and efficacy of COVID-19 vaccination in pregnancy, and clear recommendations from professional organizations and the Centers for Disease Control and Prevention (CDC) for pregnant people to get vaccinated, COVID-19 vaccine hesitancy in pregnancy remains a significant public health problem. The emergence of the highly transmissible B.1.617.2 (Delta) variant among primarily unvaccinated people has exposed the cost of vaccine hesitancy. In this commentary, we explore factors contributing to COVID-19 vaccine hesitancy in pregnancy and potential solutions to overcome them.

Key Points
Racial and Ethnic Disparities in Cancer-Associated Thrombosis
Authors: Wiredu Courteney , Haynes Norrisa , Guerra Carmen , Ky Bonnie
Published: October 2021

Active malignancy increases the risk of developing venous thromboembolism (VTE) by four- to seven-fold. The risk of VTE, including deep vein thrombosis and pulmonary embolism, in patients with cancer varies based on several clinical factors, such as cancer stage and age. However, race and ethnicity are also associated with increased VTE risk. Black (African American) patients with cancer have a higher risk of developing VTE than White patients, while Asian/Pacific Islanders have a lower risk. Studies on cancer-associated thrombosis demonstrate a need to advance our understanding of both the biologic and sociologic underpinnings of the observed differences according to race. Addressing the causes of these disparities can better health outcomes for historically underserved patient populations.
Cobalt-Catalyzed Hydroxyperfluoroalkylation of Alkenes with Perfluoroalkyl Bromides and Atmospheric Oxygen
Authors: Fan Wu , Li Suhua , Li Qiankun , Sun Qilin , Pang Liangzhi , Mao Shuxian , Zhou Yuyi , Xu Jing
Published: October 2021

A mild and efficient method for the cobalt-catalyzed hydroxyperfluoroalkylation of alkenes has been developed. This method demonstrated broad substrate scope, good yields, and mild conditions with the tolerance of mono-, di-, and trisubstituted alkenes including both styrenes and non-activated aliphatic olefins. This strategy offered a valuable solution for rapid and efficient construction of β-perfluoro­alkyl alcohols using widely available and inexpensive perfluoroalkyl bromides­ and atmospheric oxygen.
Cyanide-Free Cyanation of Aryl Iodides with Nitromethane by Using an Amphiphilic Polymer-Supported Palladium Catalyst
Authors: Uozumi Yasuhiro , Suzuka Toshimasa , Niimi Ryoko
Published: October 2021

A cyanide-free aromatic cyanation was developed that uses nitromethane as a cyanide source in water with an amphiphilic polystyrene–poly(ethylene glycol) resin-supported palladium catalyst and an alkyl halide (1-iodobutane). The cyanation proceeds through the palladium-catalyzed cross-coupling of an aryl halide with nitromethane, followed by transformation of the resultant (nitromethyl)arene intermediate into a nitrile by 1-iodobutane.
Triphenylphosphine/1,2-Diiodoethane-Promoted Formylation of Indoles with N,N-Dimethylformamide
Authors: Lin Jin-Hong , Xiao Ji-Chang , Zhu Yu-Rong
Published: October 2021

Despite intensive studies on the synthesis of 3-formylindoles, it is still highly desirable to develop efficient methods for the formylation of indoles, due to the shortcomings of the reported methods, such as inconvenient operations and/or harsh reaction conditions. Here, we describe a Ph3P/ICH2CH2I-promoted formylation of indoles with DMF under mild conditions. A Vilsmeier-type intermediate is readily formed from DMF promoted by the Ph3P/ICH2CH2I system. A one-step formylation process can be applied to various electron-rich indoles, but a hydrolysis needs to be carried out as a second step in the case of electron-deficient indoles. Convenient operations make this protocol attractive.
Swallowing Problems after Thyroidectomy
Authors: Elbeltagy Yasser Mohammed , Bassiouny Samia Elsayed , Sobhy Tamer Shokry , Ismail Ahmed Essameldin , Teaima Ahmed Abdelmoneim
Published: October 2021

Introduction Thyroidectomy is a common procedure. Certain swallowing problems could happen after this surgery and affect the quality of life of the patient.

Objective To evaluate swallowing after thyroidectomy in the early and late postoperative periods and to correlate subjective and objective parameters.

Methods A prospective study with100 patients who underwent total thyroidectomy at our institution from April 2018 to September 2019. Each patient was assessed by the Arabic version of the Eating Assessment Tool (EAT-10) questionnaire and the fiberoptic endoscopic evaluation of swallowing (FEES) preoperatively, and in the early postoperative (EPO) and late postoperative (LPO) periods.

Results The rate of dysphagia was of 82% in the EPO period, and of 36% in the LPO period. Two groups were compared regarding vocal fold mobility using the FEES. Group I included 89 patients with normal vocal fold mobility, 42% of whom had early dysphagia, and only 22% had late dysphagia. Regarding swallowing, we found that in the EPO period, the rates of delayed triggering, aspiration, penetration and residue were of 12.4%, 0%, 0%, and 42.7% respectively. Group II (unilateral immobile vocal fold) included 11 patients in the EPO evaluation, and all of them had early dysphagia.

Conclusion Swallowing problems can occur in patients after thyroidectomy regardless of alterations in larynx mobility, and they are characterized by delayed triggering and stasis of food, which are also noticed in the LPO period, though more frequently in the EPO period. Moreover, there is a highly significant correlation between the subjective and objective parameters of swallowing in both EPO and LPO periods.
Understanding How Health Providers Identify Women with Postpartum Hemorrhage: A Qualitative Study
Authors: Bento Silvana Ferreira , Borovac-Pinheiro Anderson , Tanaka Erika Zambrano , Silveira Carla , Pacagnella Rodolfo Carvalho
Published: October 2021

Objective To identify how health providers recognize postpartum hemorrhage early and the difficulties involved in it.

Methods An exploratory, descriptive study using a qualitative approach through a semi-structured interview technique. In total, 27 health professionals (nursing technicians, nurses, medical residents in Gynecology and Obstetrics, hired medical doctors, and medicine professors) working in a tertiary-level hospital of reference in women's health care in the State of São Paulo, Brazil, participated in the study through an invitation. After they accepted the invitation, they signed the free and informed consent form. All interviews were recorded and transcribed, and a thematic analysis was conducted. We found three analysis categories: a) perception of the severity: “there is something wrong with the women”; b) difficulties in the early diagnosis of postpartum hemorrhage; and c) the process to improve obstetrical care.

Results Caregivers believe teamwork and communication should be improved. Besides the visual estimation of blood loss, the nursing team is attentive to behavioral symptoms like irritability, while the medical staff follow protocols and look for objective signs, such as altered vital signs.

Conclusion Besides the objective evaluations, the subjective perceptions of the providers are involved in the clinical judgement regarding the diagnosis of postpartum hemorrhage, and this should be included in a broader diagnosis strategy.
Supplementation of Vitamin D in the Postdelivery Period of Women with Previous Gestational Diabetes Mellitus: Systematic Review and Meta-Analysis of Randomized Trials
Authors: Kron-Rodrigues Meline Rossetto , Rudge Marilza Vieira Cunha , Lima Silvana Andrea Molina
Published: October 2021

Objective To evaluate the effects of vitamin D supplementation in the postpartum period of women with previous gestational diabetes mellitus (GDM).

Methods Randomized clinical trials of pregnant women with GDM of any chronological, gestational age and parity, with no history of previous disease who received vitamin D supplementation in the prenatal and/or postpartum period and were evaluated in the postpartum period were included. The PubMed, EMBASE, Cochrane, and LILACS databases were consulted until July 2019. Serum vitamin D concentration (25-hydroxyvitamin D in nmol/L), fasting blood glucose, glycated hemoglobin, serum calcium concentration, homeostatic model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), parathyroid hormone (PTH) and body mass index (BMI) were evaluated. Similar results in at least two trials were plotted using the RevMan 5; Cochrane Collaboration, Oxford, Reino Unido. The quality of the evidence was generated according to the classification, development, and evaluation of the classification of the recommendations.

Results Four studies were included in the present review (200 women). The findings indicate that there is no difference in the postpartum period in women diagnosed with previous GDM who received vitamin D supplementation in the prenatal and/or in the postpartum period, showing only that there was a significant increase in the concentration of vitamin D (relative risk [RR]: 1.85; 95% confidence interval [CI]: 1.02–2.68).

Conclusion This increase in the concentration of vitamin D should be interpreted with caution, since the assessment of the quality of the evidence was very low. For the other analyzed outcomes, there was no significance between the intervention and control groups, and the outcomes, when analyzed in their strength of evidence, were considered very low and low in their evaluation.
Association between Adverse Maternal Clinical Outcomes and Imbalance of Cytokines and Angiogenic Factors in Preterm Preeclampsia
Authors: Nunes Priscila Rezeck , Romao-Veiga Mariana , Borges Vera Therezinha Medeiros , Matias Mariana Leticia , Ribeiro Vanessa Rocha , Costa Roberto Antonio Araujo , Peracoli Maria Terezinha Serrao , Peracoli Jose Carlos
Published: October 2021

Objective Preeclampsia (PE) is a pregnancy-specific syndrome characterized by abnormal levels of cytokines and angiogenic factors, playing a role in the disease development. The present study evaluated whether immunological markers are associated with the gestational age and with the disease severity in preeclamptic women.

Methods Ninety-five women who developed PE were stratified for gestational age as preterm PE (< 37 weeks) and term PE (≥ 37 weeks of gestation) and compared for disease severity as well as plasma concentration of angiogenic factors and cytokines. The concentrations of placental growth factor (PlGF), vascular endothelial growth factor (VEGF), Fms-like soluble tyrosine kinase (sFlt-1) and soluble endoglin (sEng), as well as the cytokines, tumor necrosis factor-α (TNF-α) and interleukin 10 (IL-10), were determined by enzyme-linked immunosorbent assay (ELISA).

Results The comparison between preeclamptic groups showed a higher percentage of severe cases in preterm PE (82.1%) than in term PE (35.9%). Similarly, the concentrations of TNF-α, sFlt-1, and sEng, as well as TNF-α/IL-10 and sFlt-1/PlGF ratios were significantly higher in the preterm PE group. In contrast, concentrations of PlGF, VEGF, and IL-10 were significantly lower in women with preterm PE. Negative correlations between TNF-α and IL-10 (r = 0.5232) and between PlGF and sFlt1 (r = −0.4158) were detected in the preterm PE.

Conclusion In pregnant women with preterm PE, there is an imbalance between immunological markers, with the predominance of anti-angiogenic factors and TNF-α, associated with adverse maternal clinical outcomes.
Clinical Experience Over 15 Years with the B-Lynch Compression Suture Technique in the Management of Postpartum Hemorrhage
Authors: Nagahama Gilberto , Korkes Henri Augusto , Sass Nelson
Published: October 2021

Objective To describe the clinical experience with the B-Lynch technique in the management of postpartum hemorrhage as well as the factors related to the indication of the technique and to present the success rates of the application of the B-Lynch technique.

Methods Observational, retrospective, cross-sectional, and analytical study. Patient data was obtained through the study of medical records. The study population comprised of patients who underwent hemostatic suture using the B-Lynch technique, including 104 patients within the period from January 1, 2005, to December 31, 2019.

Results Of the total of 104 patients, 82.7% did not present any complications. Blood transfusion and intensive care unit admission were the most prevalent complications, with 13.5% and 15.4%, respectively. Only 1% of the patients had puerperal and surgical site infections. The factors most related to the application of the technique were the presence of previous cesarean section (30.8%), use of oxytocin (16.3%), and preeclampsia (11.6%). Puerperal hysterectomy was performed in 4.8% of the patients due to failure of the method.

Conclusion The clinical experience with the B-Lynch technique was satisfactory since it presented few complications, with excellent results in hemorrhagic control. Previous cesarean section, the use of oxytocin, and preeclampsia stood out as factors related to the indication of the application of the technique, and the success rate in controlling postpartum hemorrhage was 95.2%.
Pathways of IFN-alpha Activation in Patients with Cervical Intraepithelial Neoplasia (CIN)
Authors: Tirone Nelson Ranieri , Campos Carolina Guissoni , Ferreira Kézia Jesus Aguiar , Stark Léticia Montes , Vieira Jéssica Ferreira , Murta Eddie Fernando Cândido , Michelin Márcia Antoniazi
Published: October 2021

Objective The aim of the present study was to compare the local and systemic expression of the factors linked to the interferon alpha (IFN-α) activation pathway in different degrees of cervical intraepithelial neoplasia (CIN) and cervical cancer.

Methods A total of 128 patients with CIN I, CIN II, CIN III and cervical cancer was evaluated. The real-time polymerase chain reaction (RT-PCR) technique was used to evaluate the gene expression of IFNR1, IFNR2, IFN-α, oligoadenylate synthase (2'5′OAS), cytokine signal suppressor 1 (SOCS) 1, SOCS3, signal transducer and transcription activator 1 (STAT1), and IRF9 from 128 biopsies. A total of 46 out of 128 samples were evaluated by flow cytometry for IFNAR1, IFNAR2, STAT1, IRF7 and IFN-α in peripheral blood cells.

Results Patients with CIN II and III (63 samples) had a low local expression of IFNR1, but not IFNR2. Patients with some degree of injury showed high expression of SOCS1 and SOCS3. Systemically, patients with CIN II and III (20 samples) had a significant increase in IFNR1, IFNR2, STAT1, IRF7, and IFN-α in helper, cytotoxic T lymphocytes, and in monocytes.

Conclusion Patients with high-grade lesions have increased systemic expression of IFN-α and its activation pathways in helper and cytotoxic T lymphocytes, as well as in monocytes due to an exacerbation of the immune response in these patients. This phenomenon is not accompanied by resolution of the lesion due to a defect in the IFN-α activation pathway that revealed by low local IFNAR1 expression and high local expression of SOCS1 and SOCS3.
Complete Androgen Insensitivity Syndrome: A Rare Case of Prenatal Diagnosis
Authors: Coelho Maria Liz , Soares Elisa , Freixo Marília , Brandão Pedro , Marinho Carla , Rocha Juliana , Rodrigues Graça
Published: October 2021

With the widespread uptake of noninvasive prenatal testing (NIPT), a larger cohort of women has access to fetal chromosomal sex, which increases the potential to identify prenatal sex discordance. The prenatal diagnosis of androgen insensitivity syndrome (AIS) is an incidental and rare finding. We wish to present the diagnosis of a prenatal index case after NIPT of cell-free fetal DNA and mismatch between fetal sex and ultrasound phenotype. In this particular case, the molecular analysis of the androgen receptor (AR) gene showed the presence of a pathogenic mutation, not previously reported, consistent with complete androgen insensitivity syndrome. Carrier testing for the mother revealed the presence of the same variant, confirming maternal hemizygous inheritance. Identification of the molecular basis of these genetic conditions enables the preimplantation or prenatal diagnosis in future pregnancies.
A New Perspective of COVID-19 Infection: An Epigenetics Point of View
Authors: Ozturkler Ziya , Kalkan Rasime
Published: October 2021

Coronavirus disease 2019 (COVID-2019) started in Wuhan, China, in December 2019. Angiotensin-converting enzyme 2 (ACE2) receptor was one of the most important genes related to the entrance of the virus to the host. Until now, several variations have been identified in ACE2 and related transmembrane protease serine 2. Epigenetic modifications not only play an important role during the maintenance of genome and cellular homoeostasis but also for the etiopathophysiology of the virus infection. Studies showed methylation of ACE2 was changed to depend on host and age of the host during the viral infection.

In this study, we provided an epigenetics point of view to the coronavirus infection. We highlight the importance of epigenetic modifications during viral replication and infection and their interaction with COVID-19 susceptibility and host viral response.
Influence of molecular stacking pattern on excited state dynamics of copper phthalocyanine films
Authors: Li Meng , Li Wen-hui , Hu Yu-jie , Leng Jing , Tian Wen-ming , Zhao Chun-yi , Liu Jun-xue , Cui Rong-rong , Jin Sheng-ye , Cheng Chuan-hui , Cong Shu-lin
Published: October 2021

Photophysical processes occurring within organic semiconductors is important for designing and fabricating organic solar cells. Copper phthalocyanine (CuPc) is a typical electron acceptor. In this work, the triplet exciton lifetime is prolonged by altering the molecular stacking pattern of the CuPc film. For CuPc thin films, the excited state decays are mainly determined by the triplet-triplet annihilation process. The ultrafast transient absorption measurements indicate that the primary annihilation mechanism is one-dimensional exciton diffusion collision destruction. The decay kinetics show a clearly time-dependent annihilation rate constant with γ∝t−1/2. Annihilation rate constants are determined to be γ0 = (2.87±0.02)×10−20 cm3·s−1/2 and (1.42±0.02)×10−20 cm3·s−1/2 for upright and lying-down configurations, respectively. Compared to the CuPc thin film with an upright configuration, the thin film with a lying-down configuration shows longer exciton lifetime and higher absorbance, which are beneficial to organic solar cells. The results in this work have important implications on the design and mechanistic understanding of organic optoelectronic devices.
Promoting effect of Co(OH)2 for supported Pt nanocatalysts toward catalytic hydrolysis of ammonia borane
Authors: Wang Si-yu , Huang Li , Liu Cheng-yong , He Wen-xue , Long Zhi-xin , Pan Ya , Sun Zhi-hu
Published: October 2021

Catalytic hydrolysis of ammonia borane for dehydrogenation is a promising way for generation and storage of hydrogen energy. Catalysts with reduced utilization of costly noble metals while high activity and stability are highly desired. Herein we show that the catalytic activity of the prototypical Pt/SiO2 catalysts towards ammonia borane hydrolysis could be significantly improved by the presence of a layer of Co(OH)2 beneath the supported Pt nanoparticles. By changing the Pt:Co molar ratio in the Pt-Co(OH)2/SiO2 catalysts, the hydrogen generation rates from ammonia borane hydrolysis show a volcano-type curve, with the maximum catalytic activity at the Pt:Co molar ratio of 1:11. The highest turnover frequency value of 829 molH2·molPt−1·min−1 at room temperature outperforms most of the reported Pt-based catalysts, and the apparent activation energy is drastically decreased to 36.2 kJ/mol from 61.6 kJ/mol for Pt/SiO2. The enhanced catalytic performance of Pt-Co(OH)2/SiO2 is attributed to the electrons donation from Co atoms on Co(OH)2 to Pt occurring at the metal-hydroxide interface, which is beneficial for optimizing the oxidation cleavage of the O–H bond of attacked H2O.
Super-exchange and exchange-enhanced reactivity in Fe4S4-mediated activation of SAM by radical SAM enzymes
Authors: Feng Jian-qiang , Wang Bin-ju
Published: October 2021

[4Fe-4S]-dependent radical S-adenosylmethionine (SAM) proteins are a superfamily of oxidoreductases that can catalyze a series of challenging transformations using the common 5-dAdo radical intermediate. Although the structures and functions of radical SAM enzymes have been extensively studied, the electronic state-dependent reactions of the [4Fe-4S] clusters in these enzymes are still elusive. Herein we performed QM/MM calculations to elucidate the electronic state-dependent reactivity of the [4Fe-4S] cluster in pyruvate-formate lyase activating enzyme. Our calculations show that the electronic state-dependent SAM activation by the [4Fe-4S] clusters in radical SAM enzyme is determined by both the super-exchange and exchange-enhanced reactivities. The super-exchange coupling in the [4Fe-4S] cluster favors the antiferromagnetic coupling between two neighbouring pairs, which results in the α-electron rather than the β-electron donation from the [4Fe-4S]1+ cluster toward the SAM activation. Meanwhile, in the most favorable electronic state for the reductive cleavage of S-C5′, Fe4 would donate its α-electron to gain the maximum exchange interactions in the Fe4-block. Such super-exchange and exchange-enhanced reactivity could be the general principles for reactivities of [4Fe-4S] cluster in RS enzymes.
A three-dimensional reconstruction method for the inner surface of a deep hole using a rotating mechanism
Authors: Pan Shuo , Shao Xinjie , Wang Huaiguang , Song Bin
Published: October 2021

An inner surface 3D reconstruction device structure is proposed in this paper to reconstruct the complex curved inner surface of a deep hole. First, the optical paths of the camera and the structured light transmitter are converged on the deep hole inner surface through plane mirrors to form a multi-line structured light projection system (MSLPS). The parameters of the MSLPS are then calibrated before the measurement. Second, the MSLPS rotates during the measurement process to obtain the point cloud collections of the inner surface and the rotation angles at different measurement positions are recorded. The point clouds contain the 3D surface information of the measured areas. Finally, the entire surface shape is reconstructed by the proposed reconstruction algorithm, and the feature parameters of the deep hole inner surface can be calculated by the reconstructed point cloud. The development process of the system was demonstrated in the experiment. The proposed system is validated through the reconstruction experiment of different areas in a deep hole.
Gradient magnetron co-sputtered
μ
m-thick Al–Si films on dielectric substrates for operation in the millimeter-wave band
Authors: Serdobintsev Alexey A. , Galushka Victor V. , Kozhevnikov Ilya O. , Pavlov Anton M. , Starodubov Andrey V.
Published: October 2021

Ongoing active development of modern radio frequency electronic devices operating in the millimeter (V) band, such as fifth-generation wireless communications, demands new materials to control electromagnetic interference, compatibility, and reliability of such systems. This work investigates feasibility absorptive non-reflective thin coatings deposition on dielectric substrates using simultaneous magnetron co-deposition. For this, electromagnetic waves propagation in the millimeter band through in micrometer-thick Al–Si films of varied composition was studied. The co-deposition process was controlled by the ratio of sputtered atoms fluxes. Graded segregation was observed under certain parameters of the co-deposition process, resulting in a depth gradient of an aluminum content, as confirmed by the secondary ion mass spectrometry study. A qualitative model was proposed involving aluminum-induced silicon recrystallization happening in the course of a known aluminum interlayer exchange process. The observed Al–Si segregation effect in micrometer-thick films allows for preparation of the non-reflective and absorptive material for operation in the V-band with reflection losses more than 10 dB and transmission losses around 5 dB in the bandwidth of up to 20 GHz.
Experimental investigation of single bubbles rising in stagnant liquid: Statistical analysis and image processing
Authors: Kure Ida K. , Jakobsen Hugo A. , La Forgia Nicolas , Solsvik Jannike
Published: October 2021

Despite the large effort devoted to the study of single bubbles rising in a stagnant liquid, the complex phenomena involved have resulted in a large scatter in the terminal velocity. Providing new experimental data where the statistical uncertainty is thoroughly evaluated is therefore necessary. Single bubble experiments were conducted in a tall vertical column containing stagnant liquid at ambient conditions. To track the bubbles over the spatial range, high-speed cameras were mounted on a linear unit drive. The tall column allowed us to study the effect of hydrostatic pressure and late developed bubble dynamics on the bubble motion. The bubble properties, i.e., the bubble velocity, size, shape, and trajectory, were evaluated using an image analysis processing method. The analysis includes a quantitative evaluation of important parameters involved in the handling of the raw data. Several of the existing correlations for the terminal velocity were validated against the experimental data. The data are well predicted by the correlation proposed by Tomiyama et al. [“Terminal velocity of single bubbles in surface tension force dominant regime,” Int. J. Multiphase Flow 28, 1497–1519 (2002)]. The uncertainty in the experimental data has been emphasized, providing a quantitative evaluation based on several statistical methods. The number of experimental events necessary to obtain statistical significance was evaluated using a 95% confidence interval. Satisfying precision is found to be fulfilled for 10–15 bubble rise events. For bubbles of comparable size, the statistically significant terminal velocity data were found to exhibit a small scatter.
Improved optical confinement in ambipolar field-effect transistors toward electrical injection organic lasers
Authors: Li Yun , Sabatini Randy P. , Prasad Shyamal K. K. , Hockings Evan T. , Schmidt Timothy W. , Lakhwani Girish
Published: October 2021

Increasing optical confinement is critical to lowering laser thresholds and increasing modal gain in semiconductor lasers. Here, mode-solver calculations are used to demonstrate that improvements to optical confinement are possible in organic field-effect transistor geometries by using high refractive index cladding layers. Optical experiments show that the proposed structure increases the efficiency of amplified spontaneous emission (ASE) and lowers ASE thresholds without incurring additional losses. The results suggest that the structure can be used to improve optical confinement for both optically pumped and electrical injection organic lasers where thin, low refractive index active materials are required.
Size dependence of charge retention in gold-nanoparticles sandwiched between thin layers of titanium oxide and silicon oxide
Authors: Abbas Yawar , Rezeq Moh'd , Nayfeh Ammar , Saadat Irfan
Published: October 2021

Nonvolatile memory technology is a necessary component in many electronic devices. With the scaling down of memory devices to achieve high density and low power consumption, floating gate devices encounter various challenges like high leakage current, which leads to reliability issues and a decrease in charge density. Therefore, the use of metal nanoparticles (NPs) as charge storage centers is becoming a promising candidate due to their excellent scalability and favorable reliability. In this work, we demonstrate the charge storage dependency on the size of a gold-nanoparticle (Au-NP) by using a contact mode atomic force microscope. The individually dispersed Au-NPs are sandwiched between a thin layer (3 nm) of TiO2 blocking layer and SiO2 (2 nm) tunneling layer thin films. The consecutive I–V sweeps on a pristine device of stacking TiO2/Au-NP/SiO2/n-Si show that the threshold voltage (ΔV) increases with the increase in the Au-NP size, whereas the retention shows much more stability time with smaller size NPs, in the range of 10 nm.
Virtual screening of norbornadiene-based molecular solar thermal energy storage systems using a genetic algorithm
Authors: Ree Nicolai , Koerstz Mads , Mikkelsen Kurt V. , Jensen Jan H.
Published: October 2021

We present a computational methodology for the screening of a chemical space of 1025 substituted norbornadiene molecules for promising kinetically stable molecular solar thermal (MOST) energy storage systems with high energy densities that absorb in the visible part of the solar spectrum. We use semiempirical tight-binding methods to construct a dataset of nearly 34 000 molecules and train graph convolutional networks to predict energy densities, kinetic stability, and absorption spectra and then use the models together with a genetic algorithm to search the chemical space for promising MOST energy storage systems. We identify 15 kinetically stable molecules, five of which have energy densities greater than 0.45 MJ/kg, and the main conclusion of this study is that the largest energy density that can be obtained for a single norbornadiene moiety with the substituents considered here, while maintaining a long half-life and absorption in the visible spectrum, is around 0.55 MJ/kg.
The effects of roughness levels on the instability of the boundary-layer flow over a rotating disk with an enforced axial flow
Authors: Al-Malki M. A. S. , Garrett S. J. , Camarri S. , Hussain Z.
Published: October 2021

This paper investigates the effects of surface roughness on the convective stability behavior of boundary-layer flow over a rotating disk. An enforced axial flow and the Miklavčič and Wang (MW) model of roughness are applied to this flow. The effects of both anisotropic and isotropic surface roughness on the distinct instability properties of the boundary-layer flow over a rotating disk will also be examined for this model. It is possible to implement these types of roughness on this geometric shape while considering an axial flow. This approach requires a modification for the no-slip condition and that the current boundary conditions are partial-slip conditions. The Navier–Stokes equations are used to obtain the steady mean-flow system, and linear stability equations are then formulated to obtain neutral stability curves while investigating the convective instability behavior for stationary modes. The stability analysis results are then confirmed by the linear convective growth rates for stationary disturbances and the energy analysis. The stability characteristics of the inviscid type I (or cross-flow) instability and the viscous type II instability are examined over a rough, rotating disk within the boundary layer at all axial flow rates considered. Our findings indicate that the radial grooves have a strong destabilizing effect on the type II mode as the axial flow is increased, whereas the concentric grooves and isotropic surface roughness stabilize the boundary-layer flow for the type I mode. It is worth noting that the flows over a concentrically grooved disk with increasing enforced axial flow strength are the most stable for the inviscid type I instability.
Rigid fiber motion in slightly non-Newtonian viscoelastic fluids
Authors: Férec Julien , Bertevas Erwan , Khoo Boo Cheong , Ausias Gilles , Phan-Thien Nhan
Published: October 2021

The perturbation technique based on the retardation-motion expansion is a simple method to obtain flow solutions at low Weissenberg number. In this context, this perturbation analysis is used to develop simple expressions for the motion of fibers suspended in viscoelastic fluids. In particular, the suspending fluid is characterized by a second-order fluid, Giesekus and PPT (Phan–Thien–Tanner) models, and their derivatives, such as the upper and lower convected Maxwell models. The first-order perturbation results in a similar effective velocity gradient that is exploited to express the translation and rotational motion of a single fiber and the associated extra stress tensor. In terms of a parameter related to the various viscoelastic fluid models, it is found that a fiber aligns along the vorticity direction when subjected to a shear flow. However, when a lower convected Maxwell model is considered, the elongated particle orients in the flow direction, as basically predicted by the Jeffery solution for a Newtonian suspending fluid. Furthermore, the conservation equation for particle concentration leads to particle migration in a pressure-driven flow channel and good agreement is observed with experimental data.
Band structure critical point energy in germanium–tin alloys with high tin contents
Authors: Imbrenda Dominic , Carrasco Rigo A. , Hickey Ryan , Fernando Nalin S. , Zollner Stefan , Kolodzey James
Published: October 2021

The dielectric functions of germanium–tin alloy thin-films, deposited by molecular beam epitaxy on bulk Ge substrates, with relatively high Sn contents from 15 to 27 at. %, were measured by variable angle spectroscopic ellipsometry over the wavelength range from 0.190 to 6 μm, using a combination of ultraviolet-visible and infrared ellipsometers. The band structure critical point energies, specifically the E1 and E1 + Δ1 optical transitions, were extracted from the measurements by a method of parametric oscillator modeling and second derivative analysis. With increasing Sn content, the transitions shifted to lower energies, and for alloys with less than 20% Sn, the numerical values agreed reasonably with predictions based on deformation potential theory that accounted for film strain. For the higher Sn alloys, the critical point energies from measurements agreed less well with deformation potential theory. These results provide information on the band structure of GeSn alloys with high Sn contents, which are increasingly important for long-wave infrared devices and applications.
Carbon–carbon supercapacitors: Beyond the average pore size or how electrolyte confinement and inaccessible pores affect the capacitance
Authors: Lahrar El Hassane , Simon Patrice , Merlet Céline
Published: October 2021

Carbon–carbon supercapacitors are high power electrochemical energy storage systems, which store energy through reversible ion adsorption at the electrode–electrolyte interface. Due to the complex structure of the porous carbons used as electrodes, extracting structure–property relationships in these systems remains a challenge. In this work, we conduct molecular simulations of two model supercapacitors based on nanoporous electrodes with the same average pore size, a property often used when comparing porous materials, but different morphologies. We show that the carbon with the more ordered structure, and a well defined pore size, has a much higher capacitance than the carbon with the more disordered structure and a broader pore size distribution. We analyze the structure of the confined electrolyte and show that the ions adsorbed in the ordered carbon are present in larger quantities and are also more confined than for the disordered carbon. Both aspects favor a better charge separation and thus a larger capacitance. In addition, the disordered electrodes contain a significant amount of carbon atoms, which are never in contact with the electrolyte, carry a close to zero charge, and are thus not involved in the charge storage. The total quantities of adsorbed ions and degrees of confinement do not change much with the applied potential, and as such, this work opens the door to computationally tractable screening strategies.
A numerical model for the simulation of oil–ice interaction
Authors: Abbasi H. R. , Lubbad R.
Published: October 2021

Accurate modeling of the interaction between oil and sea ice is essential for predicting oil spill fate and transport in ice-infested waters. A three-dimensional numerical model based on the smoothed particle hydrodynamics (SPH) method is incorporated to model such interactions. The effects from air and water are well captured using suitable force components and without explicit inclusion of air and water phases. This reduces the four-phase SPH model into a two-phase model, significantly reducing computational costs and potentially enabling the use of this model for large-scale simulations. We validate the model against experimental data recently available in the literature on oil–ice interactions. The experiments studied the interaction in a flume between an ice floe and oil slick for different types of crude oils. The current velocities were varied and the thicknesses of the oil slicks were measured. The validation results show that our SPH model can adequately simulate the interaction between oil slicks and ice floes. The simulated average thicknesses fit well with the measured thicknesses despite the considerable difference in the viscosity of the tested crude oil. Moreover, the effects of oil density, surface tension, viscosity, and current velocity on oil slick accumulation in front of the ice floe are studied. The higher current velocities and higher oil density lead to thicker oil slick thickness next to the ice floe. The surface tension effect on oil slick thickness is not significant. Finally, we provide estimates for the minimum oil slick thickness for a finite range of oil viscosities.
Transformation of metastable dual-phase (Ti0.25V0.25Zr0.25Hf0.25)B2 to stable high-entropy single-phase boride by thermal annealing
Authors: Feltrin Ana C. , Hedman Daniel , Akhtar Farid
Published: October 2021

Transition metal borides have a unique combination of high melting point and high chemical stability and are suitable for high temperature applications (>2000 °C). A metastable dual-phase boride (Ti0.25V0.25Zr0.25Hf0.25)B2 with distinct two hexagonal phases and with an intermediate entropy formation ability of 87.9 (eV/atom)−1 as calculated via the density functional theory (DFT) was consolidated by pulsed current sintering. Thermal annealing of the sintered dual-phase boride at 1500 °C promoted the diffusion of metallic elements between the two boride phases leading to chemical homogenization and resulted in the stabilization of a single-phase high-entropy boride. Scanning electron microscopy, in situ high temperature x-ray diffraction, and simultaneous thermal analysis of the as-sintered and annealed high-entropy borides showed the homogenization of a dual-phase to a single-phase. The experimentally obtained single-phase structure was verified by DFT calculations using special quasirandom structures, which were further used for theoretical investigations of lattice distortions and mechanical properties. Experimentally measured mechanical properties of the single-phase boride showed improved mechanical properties with a hardness of 33.2 ± 2.1 GPa, an elastic modulus of 466.0 ± 5.9 GPa, and a fracture toughness of 4.1 ± 0.6 MPa m1/2.
Impact of surface polarization and ion accumulation on electroluminescence for methylammonium lead bromide light emitting diodes
Authors: Liu Zhe , Sun Xiaojuan , Tang Jun , Pan Jing , Pan Ruiheng , Xu Ling , Wang Kai
Published: October 2021

The coexistence of polarization and mobile ions is an extraordinary property for hybrid perovskites, as they are proven critical for charge generation and transport. There is a lack of study to elucidate the slow responses of surface polarization and ion accumulation on the electroluminescence (EL) for perovskite light emitting diodes (PeLEDs). Here, we adopt ac-field impedance spectroscopy combined with in situ EL measurements for the study of surface recombination, when a prototypical methylammonium lead bromide (CH3NH3PbBr3) PeLED operates at working conditions. We have found that the surface polarization due to charges and ions has remarkable impact on EL characteristics such as the illumination intensity, full width at half maximum (FWHM), and emissive peak. Such a phenomenon can be explained by the slow surface polarization relaxation and the ion vacancy-polarization interaction. Both of them promote surface band-to-band and trap-assist recombination, while giving rise to the EL intensity. This surface science study is merit for understanding the role of surface polarization and ion accumulation for the EL generation in PeLEDs.