bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of criteria for good logistics practices for agrobusiness development
Authors: Lazarova Elitsa
Published: August 2021

The main research goal is to identify criteria for good logistics practices for the development of agribusiness in Bulgaria. The thesis is that the construction of logistics chains is a market reaction of the business for efficient use of available resources and generation of added value, contributing to cohesion between the regions in the national economy. Methods are analytical tools such as: analysis and summary of literature, tabular, graphical and schematic presentation of characteristics and trends, interview and survey on the possibilities for building logistics chains in agribusiness. The results of the study are: First. There are regional inequalities and asymmetries in territorial development. The survey data show that in less developed regions there are more logistics companies with a wide range of activities, which helps generate economic growth and achieve regional cohesion. Second. Based on the survey, the main problems and positive trends in solving internal organizational problems in business organizations are outlined. Third. The following criteria for good logistics practices in business development have been identified and substantiated: internet platform for doing business, commercial packaging and design, inventory and delivery tracking systems, shortening planning time, order processing and delivery, service and maintenance, promotional policy and establishment of logistics structures.
Influence of Gender on the Advertising Responses of Young People for Products of Mobile Operators in Bulgaria
Authors: Spasova Lyubomira , Taneva Tanya
Published: August 2021

The use of gender as a marketing strategy for market segmentation requires consideration of gender differences in information processing. This would increase the effect of advertising campaigns by adapting them to the dynamically changing market. he presented empirical study was conducted after 300 men and women aged 18 to 25 years, users of functional mobile products. The aim of the study is to determine the extent to which gender determines positive and negative advertising responses, identifying subjective judgments. The results of the research are empirical confirmation of some basic hypotheses of the Selective model of information processing in advertising messages: objectivity in the processing of information by men and subjectivity in the processing of information by women; selectivity in the perception of the attributes of the product by men and integrity - by women and a stronger willingness to use new products by women than by men. The present study offers an empirical hypothesis that women form positive responses to a larger number of signals in advertising, while men form negative responses to a larger number of signals in advertising messages. Satisfaction is proving to be a very important factor in advertising responses for both sexes, as it is a stronger factor for women, and men’s frustration with a mobile product is stronger than for women.
EU funding state for improving the quality of higher education in Bulgaria
Authors: Hristova Sevdalina
Published: August 2021

The quality of higher education is one of the critical factors for increasing the competitiveness of the Bulgarian economy and the development of the regions. The financing of the higher education system is one of the main factors for the quality of the provided educational service in higher schools, which is dwelled upon in the Strategy for Development of Higher Education. The aim of the author is to explore the possibilities for using European funding for projects of higher education institutions under the operational programs and on this basis to outline some guidelines for improving the effectiveness of project funding in the sector and enhancing the quality of higher education. In order to determine the role of project funding under the operational programs for improving the quality of higher education in Bulgaria, interviews with experts have been conducted. The results of the research are processed by content analysis and are summarized in the paper. They are the basis of the main conclusions and recommendations for improving the quality of education in Bulgaria.
Main Dependences between Gender, Financial Status and Indicators Predicting Purchase of Mobile Products and Services in Bulgaria
Authors: Spasosva Lyubomira
Published: August 2021

The present study was conducted in order to establish the main relationships between gender and financial status on indicators influencing the purchase of a mobile operator. Basic indicators for measuring consumer behavior are derived, applying analysis of variations, ANOVA, and correlation analyses to check the strength of indicators influence. According to the results of statistical data processing, two groups were identified: the most favorable group for influence – young women who are financially disadvantaged, and one on which it is difficult to achieve advertising impact of mobile operator. The practical applicability of the study is significant, as mobile operators in Bulgaria can have a much more successful impact on the group with a higher propensity to try new, specific products, as well as those who declare greater confidence in a mobile company, built through the influence of advertising.
Sprachliche Validierung des Fibrose-Fragebogens zur Erfassung der Lebensqualität bei Patienten mit idiopathischer Lungenfibrose und idiopathischer nichtspezifischer interstitieller Pneumonie
Authors: Kirsten D. , de Vries U. , Costabel U. , Koschel D. , Bonella F. , Günther A. , Behr J. , Claussen M. , Schwarz S. , Prasse A. , Kreuter M.
Published: August 2021

Idiopathische interstitielle Pneumonien sind mit einer deutlichen Minderung der Lebensqualität (LQ) assoziiert. Es existiert in Deutschland lediglich der Lebensqualitätsfragebogen für Patienten mit interstitiellen Lungenerkrankungen (K-BILD; 1) und eine deutsche Validierung von Kreuter et al. 2 Dieser Fragebogen ist jedoch in der präzisen Erfassung der Lebensqualität (LQ) für Fibrosepatienten eingeschränkt. Daher wurde ein Fragebogen zur Lebensqualität von Patienten mit idiopathischer Lungenfibrose und nicht-spezifischer interstitieller Pneumonie (Fibrose-Fragebogen, FFB) entwickelt und sprachlich validiert.

Methode Die linguistische Validierung des FFB erfolgte in einem mehrstufigen Prozess durch enge Zusammenarbeit der Entwickler des Fragebogens mit bilingualen, professionellen Übersetzern durch Hin- und Rückübersetzung, um eine deutsche und englische Version zu erstellen. Ein Vergleich mit dem St. Georges Respiratory Questionnaire (SGRQ) wurde durchgeführt.

Ergebnisse Es wurden eine deutsche und eine englische Version des FFB linguistisch validiert. Die Fragen umfassen 5 Skalen und 23 Items mit Aussagen zur Befindlichkeit, Beeinträchtigung und Fragen zu Symptomen wie Atemnot und Husten sowie eine visuelle Analog-Skala zum allgemeinen Gesundheitszustand.

Schlussfolgerung Die deutsche und die englische Version des FFB erlauben den klinischen und wissenschaftlichen Einsatz bei Patienten mit progressiver Lungenfibrose wie der idiopathischen Lungenfibrose (IPF) und der idiopathischen nicht-spezifischen Lungenfibrose (iNSIP), um die Lebensqualität zuverlässig bestimmen zu können. Im Verlauf der Erkrankung kann der Einsatz dieses Fragebogens hilfreich sein.
Myositis – die Vielfalt wird neu verstanden
Authors: Feist Eugen
Published: August 2021

Seit unserem letzten Themenheft zu den „Idiopathischen inflammatorischen Myopathien“, die wir Rheumatologen auch gerne als „Myositiden“ bezeichnen, haben sich bei diesem interdisziplinären Krankheitsspektrum sehr viele neue Erkenntnisse durchgesetzt. Darauf begründet, habe ich den vormaligen Titel meines Editorials „…die Vielfalt wird neu geordnet“ nunmehr in „…die Vielfalt wird neu verstanden“ abgeändert.
Editorial
Authors: Bengel Jürgen , Meyer Thorsten
Published: August 2021

Liebe Leserinnen, liebe Leser,

in der letzten Ausgabe unserer Zeitschrift haben wir Ihnen eine neue Herausgeberin und zwei neue Herausgeber vorgestellt. Nun möchten wir eine weitere Veränderung bekanntgeben. Nach sieben Jahren wird sich Prof. Jürgen Bengel als federführender Herausgeber verabschieden. Die Schriftleitung geht zum 1. Oktober dieses Jahres an Prof. Thorsten Meyer über.
Comparison of endoscopic resection techniques for duodenal neuroendocrine tumors: systematic review
Authors: Brito Helcio Pedrosa , Torres Isabela Trindade , Turke Karine Corcione , Parada Artur Adolfo , Waisberg Jaques , Botelho Ricardo Vieira
Published: August 2021

Background and study aims Regardless of size, duodenal neuroendocrine tumors (dNETs) should be considered potentially malignant. A complete resection without complications is essential to increase safety procedures. The aim of this review was to describe effectiveness and possible complications of endoscopic techniques resection for resectioning dNETs in patients with tumors ≤ 20 mm in diameter.

Methods An electronic bibliographic search was conducted using MEDLINE (via PubMed), Embase, Cochrane Central, and Google Scholar virtual databases. The types of intervention were endoscopic mucosal resection alone (EMR) or with cap (EMR-C), with a ligation device (EMR-L), with previous elevation of the tumor (EMR-I) or with endoscopic submucosal dissection (ESD); argon plasm coagulation (APC), and polypectomy. The outcome measures adopted were presence of free margin associated with tumor resection, tumor recurrence, complications (bleeding and perforation), and length of the procedure.

Results Ten publications were included with the result of 224 dNET resections. EMR alone and polypectomy resulted in the most significantly compromised margin. The most frequent complication was bleeding (n = 21), followed by perforation (n = 8). Recurrence occurred in 13 cases, the majority of those under EMR or EMR-I.

Conclusions EMR-C or EMR-I should be preferred for resectioning of dNETs. Polypectomy should not be indicated for resection of dNETs due to the high occurrence of incomplete resections. EMR alone must be avoided due a higher frequency of compromised margin and recurrent surgery. ESD was associated with no recurrence, however, but an increased occurrence of bleeding and perforation.
Radiologisches Monitoring bei Immuntherapie des Nierenzellkarzinoms
Authors: Lennartz Simon , Persigehl Thorsten
Published: August 2021

In der Radiologie stellen die Response Evaluation Criteria in Solid Tumors (RECIST 1.1) die aktuell am weitesten etablierten Bewertungskriterien für das standardisierte Therapiemonitoring bei soliden Tumoren von klassischen zytostatischen und zytotoxischen Tumortherapien dar. Der zunehmende Einsatz von Immuncheckpointinhibitoren in der Therapie des metastasierten Nierenzellkarzinoms stellt das radiologische Therapiemonitoring durch das Auftreten atypischer Ansprechmuster und immuntherapiespezifischer Nebenwirkungen vor besondere Herausforderungen. Hier können angepasste Kriterien, wie beispielsweise immune RECIST (iRECIST), bei der Verlaufsbeurteilung des Nierenzellkarzinoms helfen, sowohl innerhalb als auch außerhalb klinischer Studien atypische Verläufe unter Immuncheckpointinhibitortherapie zu erfassen.
Education and gastroenterology fellow knowledge about endoscopic mucosal resection of colon adenomas: a survey-based study
Authors: Garg Shashank , Inamdar Sumant , Tharian Benjamin , Muniraj Thiruvengadam , Aslanian Harry R.
Published: August 2021

Background and study aims Endoscopic mucosal resection (EMR) is an effective way to remove large (> 2 cm) colon adenomas. Training about it has not been standardized in fellowship programs. This study was aimed at evaluating the education and knowledge of gastroenterology fellows about EMR of colorectal adenomas.

Methods Participation in this survey was offered to 1730 gastroenterology fellows in the United States during the academic year 2019 to 2020. The survey assessed endoscopic mucosal resection training and knowledge and was approved and administered by the American College of Gastroenterology.

Results A total of 163 fellows (9.4 %) completed the survey. Only 85 fellows (52.1 %) reported receiving formal education in endoscopic mucosal resection. Fellow confidence was lowest regarding knowing electrosurgery unit settings. Fewer fellows correctly identified Paris 0-IIb (79, 48.5 %; P < 0.0001) or NICE I (114, 69.9 %; P < 0.01) lesions as compared to other Paris and NICE III lesions, respectively. Only 73 (44.8 %) and 93 fellows (57.1 %) arranged steps of EMR in the correct order and identified the correct type of current used for resection, respectively. Training year, male sex, and provision of advanced endoscopy rotations during fellowship were associated with a higher knowledge score for EMR.

Conclusions Nearly half of all fellows reported no formal education in EMR and incorrectly ordered its steps. Adenoma assessment by Paris and NICE classifications and electrosurgery unit settings were the most prominent knowledge deficiencies. Incorporation of standardized training about EMR with inclusion of advanced endoscopy rotations appears to be an important educational opportunity during gastroenterology fellowship.
Effectiveness of hemostatic powders in lower gastrointestinal bleeding: a systematic review and meta-analysis
Authors: Facciorusso Antonio , Bertini Marco , Bertoni Michele , Tartaglia Nicola , Pacilli Mario , Ramai Daryl , Mohan Babu P. , Chandan Saurabh , Ambrosi Antonio , Sacco Rodolfo
Published: August 2021

Background and study aims There is limited evidence on the effectiveness of hemostatic powders in the management of lower gastrointestinal bleeding (LGIB). We aimed to provide a pooled estimate of their effectiveness and safety based on the current literature.

Patients and methods Literature review was based on computerized bibliographic search of the main databases through to December 2020. Immediate hemostasis, rebleeding rate, adverse events, and mortality were the outcomes of the analysis. Pooled effects were calculated using a random-effects model.

Results A total of 9 studies with 194 patients were included in the meta-analysis. Immediate hemostasis was achieved in 95 % of patients (95 % confidence interval [CI] 91.6 %–98.5 %), with no difference based on treatment strategy or bleeding etiology. Pooled 7- and 30-day rebleeding rates were 10.9 % (95 %CI 4.2 %–17.6 %) and 14.3 % (95 %CI 7.3 %–21.2 %), respectively. Need for embolization and surgery were 1.7 % (95 %CI 0 %–3.5 %) and 2.4 % (95 %CI 0.3 %–4.6 %), respectively. Overall, two patients (1.9 %, 95 %CI 0 %–3.8 %) experienced mild abdominal pain after powder application, and three bleeding-related deaths (2.3 %, 95 %CI 0.2 %–4.3 %) were registered in the included studies.

Conclusion Novel hemostatic powders represent a user-friendly and effective tool in the management of lower gastrointestinal bleeding.
Effects of Different Bleaching Agents on the Surface Topography and the Microhardness of Artificial Carious Lesions
Authors: Owda Rasha , Sancakli Hande Sar
Published: August 2021

Objectives The aim of this study was to evaluate the effects of in-office and at-home bleaching agent applications on the surface topography and microhardness of artificially demineralized enamel.

Materials and Methods A total of 224 enamel specimens were prepared using bovine sound central incisors. 4 mm × 4 mm enamel windows were exposed on the buccal surfaces covering the remaining surface with nail varnish. Samples were immersed in a demineralizing solution for 16 hours to produce artificial caries lesions, then divided into four groups according to the bleaching agent’s type and concentration. Group I; in-office bleaching 35% hydrogen peroxide (HP) (Whiteness HP Maxx; FGM, Brazil), Group II and Group III at-home bleaching 16 and 22% carbamide peroxide CP, respectively (Whiteness Perfect). Group IV; control (not bleached). The microhardness Vickers hardness number (VHN) was measured at the baseline, after demineralization, and after bleaching consequently. The micro-surface changes of the enamel surface after demineralization and bleaching were evaluated by scanning electron microscope (SEM).

Statistical Analysis Data were evaluated by the one-way analysis of variance (ANOVA) test followed by Post Hoc Tukey’s and Fisher’s least significant difference. Tow- sided p-values were considered statistically significant at p ≤ 0.05.

Results A significant reduction was noticed in the enamel microhardness after demineralization p < 0.05. However, there is no statistically significant difference between the mean VHN of the demineralized and bleached enamel (p > 0.001). SEM images showed significant changes on the surface of the demineralized enamel after bleaching (pattern type III).

Conclusions The low and high concentrations of HP and CP bleaching agents increased the demineralization severity of artificial caries lesions without significantly altering their microhardness values.
Preliminary Histological Evaluation of the Application of Ozone in the First Days of Orthodontic Force Induction in Animal Model
Authors: Faccini Melissa , Agostini Felipe , Drieu Tassio , Campos Francisco Ubiratan Ferreira de , Garcez Aguinaldo , Carinhena Glauber Fabre , Salmeron Samira , Casaroto Ana Regina , Valarelli Fabricio Pinelli , Freitas Karina Maria Salvatore
Published: August 2021

Objectives The aim of the study was to histologically evaluate the effect of ozone therapy on orthodontic force induction in an animal model.

Materials and Methods Twenty-four Wistar rats were divided into three groups (n = 8). A NiTi coil spring was installed from the maxillary first molar to the maxillary central incisor. G1 was control and G2/G3 received 1 mL of ozonated gas at concentrations of 10 and 60 µg/mL, in the buccal mucosa above the first molar roots. The animals were euthanized 3 and 5 days after the procedure. Histological sections were obtained, longitudinally of the first molar’ long axis, in the mesiodistal direction. The number of osteoclasts, osteoblasts, blood vessels, polymorphonuclear and mononuclear cells, formation of osteoid tissue and hyaline areas, and root resorption were evaluated with light microscope, in tension and pressure sides. Intergroup comparisons were performed with Kruskal–Wallis, Dunn, and Chi-square tests.

Results At 3-days pressure side, a greater number of osteoclasts was observed in ozone groups and greater number of blood vessels and polymorphonuclear cells were observed in G2. On the tension side, there was a significantly greater number of blood vessels, osteoblasts, and mononuclear cells in G2. At 5-days pressure side, there was a significantly greater number of osteoclasts in G2, blood vessels and osteoblasts in the ozone groups, and lesser number of polymorphonuclear cells in G3.

Conclusion Ozone therapy increased the number of osteoclasts on the pressure side and osteoblasts on tension side, in 10 µg/mL concentration, demonstrating histological parameters favorable to bone remodeling. The 60 µg/mL ozone concentration accelerated the periodontal ligament reorganization process.
Microscope-Assisted Arterial Anastomosis in Adult Living Donor Liver Transplantation: A Systematic Review and Meta-analysis of Outcomes
Authors: Ebner Peggy J. , Bick Katherine J. , Emamaullee Juliet , Stanton Eloise W. , Gould Daniel J. , Patel Ketan M. , Genyk Yuri , Sher Linda , Carey Joseph N.
Published: August 2021

Background Living donor liver transplantation (LDLT) has expanded the availability of liver transplant but has been associated with early technical complications including the devastating complication of hepatic artery thrombosis (HAT), which has been reported to occur in 14% to 25% of LDLT using standard anastomotic techniques. Microvascular hepatic artery reconstruction (MHAR) has been implemented in an attempt to decrease rates of HAT. The purpose of this study was to review the available literature in LDLT, specifically related to MHAR to determine its impact on rates of posttransplant complications including HAT.

Methods A systematic review was conducted using PubMed/Medline and Web of Science. Case series and reviews describing reports of microscope-assisted hepatic artery anastomosis in adult patients were considered for meta-analysis of factors contributing to HAT.

Results In all, 462 abstracts were screened, resulting in 20 studies that were included in the meta-analysis. This analysis included 2,457 patients from eight countries. The pooled rate of HAT was 2.20% with an overall effect size of 0.00906.

Conclusion Systematic literature review suggests that MHAR during LDLT reduces vascular complications and improves outcomes posttransplant. Microvascular surgeons and transplant surgeons should collaborate when technical challenges such as small vessel size, short donor pedicle, or dissection of the recipient vessel wall are present.
The Role of Fibrin(ogen) in Wound Healing and Infection Control
Authors: Kearney Katherine J. , Ariëns Robert A.S. , Macrae Fraser L.
Published: August 2021

Fibrinogen, one of the most abundant plasma proteins playing a key role in hemostasis, is an important modulator of wound healing and host defense against microbes. In the current review, we address the role of fibrin(ogen) throughout the process of wound healing and subsequent tissue repair. Initially fibrin(ogen) acts as a provisional matrix supporting incoming leukocytes and acting as reservoir for growth factors. It later goes on to support re-epithelialization, angiogenesis, and fibroplasia. Importantly, removal of fibrin(ogen) from the wound is essential for wound healing to progress. We also discuss how fibrin(ogen) functions through several mechanisms to protect the host against bacterial infection by providing a physical barrier, entrapment of bacteria in fibrin(ogen) networks, and by directing immune cell function. The central role of fibrin(ogen) in defense against bacterial infection has made it a target of bacterial proteins, evolved to interact with fibrin(ogen) to manipulate clot formation and degradation for the purpose of promoting microbial virulence and survival. Further understanding of the dual roles of fibrin(ogen) in wound healing and infection could provide novel means of therapy to improve recovery from surgical or chronic wounds and help to prevent infection from highly virulent bacterial strains, including those resistant to antibiotics.
Clopidogrel versus Ticagrelor in CYP2C19 Loss-of-Function Allele Noncarriers: A Real-World Study in China
Authors: Zhang Yunnan , Zhang Yi , Shi Xiujin , Lin Baidi , Han Jialun , Wang Yifan , Yan Jialin , Peng Wenxing , Li Wenzheng , Zheng Ze , Lin Yang
Published: August 2021

Objective This article compares the clinical outcomes of clopidogrel and ticagrelor in patients with acute coronary syndrome (ACS) without cytochrome P450 (CYP)2C19 loss-of-function (LOF) alleles and investigates whether clopidogrel could be an alternative P2Y12 inhibitor without increasing the risk of ischemic events.

Methods Patients were divided into the clopidogrel-treated group and the ticagrelor-treated group. Inverse probability of treatment weighting (IPTW) calculated by propensity scores was used to adjust confounding covariates. The primary outcome was major adverse cardiovascular or cerebrovascular events (MACCEs) within 12 months. The secondary outcomes were MACCEs plus unstable angina, and clinically significant bleeding events.

Results Finally, 2,199 patients were included. Of them, 1,606 were treated with clopidogrel, and 593 were treated with ticagrelor. The mean age of the original cohort was 59.92 ± 9.81 years. During the 12-month follow-up period, MACCEs occurred in 89 patients (4.0%). No significant differences were observed in MACCEs (IPTW-adjusted hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.65–1.18), MACCEs plus unstable angina (IPTW-adjusted HR, 1.20; 95% CI, 0.91–1.59), or clinically significant bleeding events (IPTW-adjusted HR, 0.81; 95% CI, 0.53–1.23) between the clopidogrel- and ticagrelor-treated groups.

Conclusion In patients with ACS without CYP2C19 LOF alleles, clopidogrel was not associated with a higher risk of MACCEs when compared with ticagrelor. The main findings of this study support use of clopidogrel in CYP2C19 LOF noncarriers as an alternative P2Y12 inhibitor, which may reduce medical expenses and adverse reactions caused by more potent P2Y12 inhibitors in these patients.
Prevention of Venous Thromboembolism in Microvascular Surgery Patients Using Weight-Based Unfractionated Heparin Infusions
Authors: Bertolaccini Corinne M. , Prazak Ann Marie B. , Goodwin Isak A. , Kwok Alvin , Mendenhall Shaun D. , Rockwell W. Bradford , Agarwal Jayant , Pannucci Christopher J.
Published: August 2021

Background Unfractionated heparin infusions are commonly used in microvascular surgery to prevent microvascular thrombosis. Previously, fixed-dose heparin infusions were believed to provide sufficient venous thromboembolism (VTE) prophylaxis; however, we now know that this practice is inadequate for the majority of patients. Anti-factor Xa (aFXa) level is a measure of unfractionated heparin efficacy and safety. This study evaluated the pharmacodynamics of weight-based dose heparin infusions and the impacts of real-time aFXa-guided heparin dose adjustments.

Methods This prospective clinical trial enrolled adult microvascular surgery patients who received a weight-based heparin dose following a microsurgical procedure. Steady-state aFXa levels were monitored, and patients with out-of-range levels received dose adjustments. The study outcomes assessed were aFXa levels at a dose of heparin 10 units/kg/hour, time to adequate aFXa level, number of dose adjustments required to reach in-range aFXa levels, and clinically relevant bleeding and VTE at 90 days.

Results Twenty-one patients were prospectively recruited, and usable data were available for twenty patients. Four of twenty patients (20%) had adequate prophylaxis at a heparin dose of 10 units/kg/hour. Among patients who received dose adjustments and achieved in-range aFXa levels, the median number of dose adjustments was 2 and the median weight-based dose was 11 units/kg/hour. The percentage of patients with in-range levels was significantly increased (65 vs. 15%, p = 0.0002) as a result of real-time dose adjustments. The rate of VTE at 90 days was 0%, and clinically relevant bleeding rate at 90 days was 15%.

Conclusion Weight-based heparin infusions at a rate of 10 units/kg/hour provide a detectable level of anticoagulation for some patients following microsurgical procedures, but most patients require dose adjustment to ensure adequate VTE prophylaxis.
The cosmic ray-driven streaming instability in astrophysical and space plasmas
Authors: Marcowith A. , van Marle A. J. , Plotnikov I.
Published: August 2021

Energetic non-thermal particles, or cosmic rays, are a major component of astrophysical plasmas next to magnetic fields, radiation, and thermal gas. Cosmic rays are usually sub-dominant in density but carry as much pressure as the thermal plasma background. In some cases, cosmic rays drift at faster speeds with respect to the normal modes' phase speeds of the background plasma. Because of this, cosmic rays are a strong source of free energy that causes new classes of kinetic or convective instabilities. Recent years have seen the development of intense analytical and numerical efforts to analyze the onset of an instability produced by the motion of these particles at fast bulk speeds: this is the streaming instability. The streaming instability has been applied to different space plasmas and astrophysical contexts like strong shocks, jets, or in interstellar and intergalactic medium studies. Streaming instabilities participate in the production of magnetic turbulence at scales corresponding to the gyroradius of the particles. By scattering off their self-generated waves, cosmic rays are coupled to the background thermal plasma. This mechanism is able to self-confine cosmic rays around sources and launch winds out of the disk of the galaxy, hence impacting galactic matter dynamics and ultimately the galactic star formation rate. We discuss a few science cases, which should be accessible in the near future for analytical calculations and numerical simulations.
Lees–Edwards boundary conditions for translation invariant shear flow: Implementation and transport properties
Authors: Bindgen Sebastian , Weik Florian , Weeber Rudolf , Koos Erin , de Buyl Pierre
Published: August 2021

Molecular dynamics (MD) simulations represent a powerful investigation tool in the field of soft matter. By using shear flows, one can probe the bulk rheology of complex fluids, also beyond the linear response regime, in a way that imitates laboratory experiments. One solution to impose a shear flow in particle-based simulations is the Lees–Edwards technique, which ensures that particles experience shear by imposing rules for motion and interactions across the boundary in the direction of the shear plane. Despite their presentation in 1972, a readily available public implementation of Lees–Edwards boundary conditions has been missing from MD simulation codes. In this article, we present our implementation of the Lees–Edwards technique and discuss the relevant technical choices. We used ESPResSo, the extensible simulation package for research on soft matter, for molecular dynamics simulations which can be used as a reference for other implementers. We illustrate our implementation using bulk dissipative particle dynamics fluids, compare different viscosity measurement techniques, and observe the anomalous diffusion in our samples during continuous and oscillatory shear, in good comparison with theoretical estimates.
Radius selection using kernel density estimation for the computation of nonlinear measures
Authors: Medrano Johan , Kheddar Abderrahmane , Lesne Annick , Ramdani Sofiane
Published: August 2021

When nonlinear measures are estimated from sampled temporal signals with finite-length, a radius parameter must be carefully selected to avoid a poor estimation. These measures are generally derived from the correlation integral, which quantifies the probability of finding neighbors, i.e., pair of points spaced by less than the radius parameter. While each nonlinear measure comes with several specific empirical rules to select a radius value, we provide a systematic selection method. We show that the optimal radius for nonlinear measures can be approximated by the optimal bandwidth of a Kernel Density Estimator (KDE) related to the correlation sum. The KDE framework provides non-parametric tools to approximate a density function from finite samples (e.g., histograms) and optimal methods to select a smoothing parameter, the bandwidth (e.g., bin width in histograms). We use results from KDE to derive a closed-form expression for the optimal radius. The latter is used to compute the correlation dimension and to construct recurrence plots yielding an estimate of Kolmogorov–Sinai entropy. We assess our method through numerical experiments on signals generated by nonlinear systems and experimental electroencephalographic time series.
Covalently linked hydrogen bond donors: The other side of molecular frustration in deep eutectic solvents
Authors: Recker Elizabeth A. , Hardy David , Anderson Grace I. , Mirjafari Arsalan , Wagle Durgesh V.
Published: August 2021

In this work, we investigated the effects of a single covalent link between hydrogen bond donor species on the behavior of deep eutectic solvents (DESs) and shed light on the resulting interactions at molecular scale that influence the overall physical nature of the DES system. We have compared sugar-based DES mixtures, 1:2 choline chloride/glucose [DES(g)] and 1:1 choline chloride/trehalose [DES(t)]. Trehalose is a disaccharide composed of two glucose units that are connected by an α-1,4-glycosidic bond, thus making it an ideal candidate for comparison with glucose containing DES(g). The differential scanning calorimetric analysis of these chemically close DES systems revealed significant difference in their phase transition behavior. The DES(g) exhibited a glass transition temperature of −58 °C and behaved like a fluid at higher temperatures, whereas DES(t) exhibited marginal phase change behavior at −11 °C and no change in the phase behavior at higher temperatures. The simulations revealed that the presence of the glycosidic bond between sugar units in DES(t) hindered free movement of sugar units in trehalose, thus reducing the number of interactions with choline chloride compared to free glucose molecules in DES(g). This was further confirmed using quantum theory of atoms in molecule analysis that involved determination of bond critical points (BCPs) using Laplacian of electron density. The analysis revealed a significantly higher number of BCPs between choline chloride and sugar in DES(g) compared to DES(t). The DES(g) exhibited a higher amount of charge transfer between the choline cation and sugar, and better interaction energy and enthalpy of formation compared to DES(t). This is a result of the ability of free glucose molecules to completely surround choline chloride in DES(g) and form a higher number of interactions. The entropy of formation for DES(t) was slightly higher than that for DES(g), which is a result of fewer interactions between trehalose and choline chloride. In summary, the presence of the glycosidic bond between the sugar units in trehalose limited their movement, thus resulting in fewer interactions with choline chloride. This limited movement in turn diminishes the ability of the hydrogen bond donor to disrupt the molecular packing within the lattice structure of the hydrogen bond acceptor (and vice versa), a crucial factor that lowers the melting point of DES mixtures. This inability to move due to the presence of the glycosidic bond in trehalose significantly influences the physical state of the DES(t) system, making it behave like a semi-solid material, whereas DES(g) behaves like a liquid material at room temperature.
Self-assembly of ionic and non-ionic surfactants in type IV cerium nitrate and urea based deep eutectic solvent
Authors: Manasi Iva , Andalibi Mohammad R. , Atri Ria S. , Hooton Jake , King Stephen M. , Edler Karen J.
Published: August 2021

Understanding and manipulating micelle morphology are key to exploiting surfactants in various applications. Recent studies have shown surfactant self-assembly in a variety of Deep Eutectic Solvents (DESs) where both the nature of surfactants and the interaction of the surfactant molecule with the solvent components influence the size, shape, and morphology of the micelles formed. So far, micelle formation has only been reported in type III DESs, consisting solely of organic species. In this work, we have explored the self-assembly of cationic surfactant dodecyl trimethylammonium nitrate/bromide (C12TANO3/C12TAB), anionic surfactant sodium dodecyl sulfate (SDS), and non-ionic surfactants hexaethylene glycol monododecyl ether (C12EO6) and octaethylene glycol monohexadecyl ether (C16EO8) in a type IV DES comprising metal salt, cerium (III) nitrate hexahydrate, and a hydrogen bond donor, urea, in the molar ratio 1:3.5. C12TANO3, C12TAB, C12EO6, and C16EO8 form spherical micelles in the DES with the micelle size dependent on both the surfactant alkyl chain length and the head group, whereas SDS forms cylindrical micelles. We hypothesize that the difference in the micelle shape can be explained by counterion stabilization of the SDS headgroup by polycations in the DES compared to the nitrate/bromide anion interaction in the case of cationic surfactants or molecular interaction of the urea and the salting out effect of (CeNO3)3 in the DES on the alkyl chains/polyethoxy headgroup for non-ionic surfactants. These studies deepen our understanding of amphiphile self-assembly in this novel, ionic, and hydrogen-bonding solvent, raising the opportunity to use these structures as liquid crystalline templates to generate porosity in metal oxides (ceria) that can be synthesized using these DESs.
Enhanced water transport through short nanochannels by regulating the direction of hydrostatic pressure
Authors: Zhang Qi-Lin , Wu Ya-Xian , Wang Gang , Yang Rong-Yao , Liu Shu-Guang
Published: August 2021

Molecular dynamics simulations are carried out to study the transport properties of water molecules across 1.34 nm long single-walled carbon nanotubes (SWCNTs) under hydrostatic pressure with different directions. It is found that when the deflection angle φ between the hydrostatic pressure and the tube-axis direction changes from 0° to 90°, the net flux shows significant differences. It is interesting to note that the maximum flux is counter-intuitively obtained at φ=45°, which is about three times that of at φ=0°. This enhancement is mainly attributed to the excellent intermolecular structure, the orientation distribution, and the filling rate of in-tube water at φ=45°. Yet, it is worth noting that with the increase of the length of the SWCNT, the anomalous effect will gradually weaken until it almost disappears. Our work is of great significance for the practical application of high-efficiency nanofiltration membranes under pressure gradients.
Unsteady behaviors of natural convection flow of a reactant in a thin finned enclosure
Authors: Roy Nepal Chandra
Published: August 2021

Steady, oscillating, and chaotic behaviors of natural convection flow of a reacting chemical are investigated taking into account the effects of a fin attached to the left vertical wall of a square enclosure. The steady-state results expose that an increase in the Rayleigh number for thermal diffusion leads to higher convection but lower temperature. On the other hand, the magnitude of the stream function, maximum temperature, and heat transfer through the walls of the cavity significantly increase with higher Frank-Kamenetskii number. When the height of the fin is increased, the convective flow and the maximum temperature are found to considerably decrease. For continued increasing of Rayleigh number and Frank-Kamenetskii number from their lower values, the convection demonstrates steady-state, oscillating to steady-state, single-periodic oscillating, multi-periodic oscillating, and chaotic characteristics. Moreover, the region of the steady-state convection for the fin in the middle of the left vertical wall is wider in comparison to that of the fin at 0.7. However, the converse results have been recognized for single-periodic and multi-periodic regions.
Enhancement of the photoelectrochemical properties of a CuGaSe2-based photocathode for water reduction induced by loading of a Cu-deficient layer at the p–n heterointerface
Authors: Ikeda Shigeru , Okamoto Riku , Ishizuka Shogo
Published: August 2021

Photoelectrochemical activity for water reduction (H2 liberation) over a co-evaporated CuGaSe2 compact thin film modified with a CdS layer and Pt deposits under simulated sunlight (AM 1.5G) radiation was evaluated, specifically focusing on the impact of a Cu-deficient layer (CDL) loaded on the top part of the CuGaSe2 film. It was found that the intentional loading of the CDL with an appropriate thickness was effective for achieving a large current flow and relatively positive photocurrent onset. The half-cell solar-to-hydrogen efficiency reached 6.6% over the best photocathode used. Moreover, the highest photocurrent onset potential of more than 0.9 V vs reversible hydrogen electrode was achieved over the photocathode based on the CuGaSe2 film having an extremely thick CDL (200 nm) with a relatively thick CdS layer (90 nm) due to efficient spatial separation of photogenerated carriers.
Abnormal threshold voltage shifts in p-channel low temperature polycrystalline silicon TFTs under deep UV irradiation
Authors: Cheng Hong , Lin Xinnan
Published: August 2021

The electrical properties of p-channel low temperature polycrystalline silicon (LTPS) thin film transistors (TFTs) under deep ultraviolet (UV) irradiation were studied. Characteristics including threshold voltage (Vth), hole field effect mobility (μeff) subthreshold swing (SS), and leakage current (Ioff) were investigated as a function of UV irradiation doses from 4 to 20 J/cm2. With an increase in UV irradiation dosage, the Vth shift of the TFT showed a turnaround effect, which first shifted to the positive direction and then shifted back to the negative direction after a UV irradiation dose of 16 J/cm2. The continuous degradation of SS and μeff was discovered with the enhancement of UV irradiation dose. To better understand the physical mechanisms underlying these characteristic changes, UV induced traps at poly-Si grain boundaries, traps at the poly-Si and gate oxide insulator (poly-Si/SiO2) interface, and trapped charges in the gate oxide were studied with a function of UV irradiation doses.
Experimental study of underwater pulse detonation gas jets: Bubble velocity field and time–frequency characteristics of pressure field
Authors: Liu Wei , Li Ning , Huang Xiao-long , Kang Yang , Li Can , Qiang Wei , Weng Chun-sheng
Published: August 2021

Underwater pulse detonation gas jets generated by a detonation tube are experimentally investigated in this study utilizing detonations in explosive gas mixtures to generate pulsating bubbles under water. Three stoichiometric gaseous fuels (methane, hydrogen, and acetylene) are detonated with oxygen under the same filling conditions. Digital particle image velocimetry and wavelet transform techniques are introduced to analyze bubble dynamics and pressure field characteristics by means of which the velocity field of the bubble interface and the time–frequency distributions of the pressure response under water are elucidated, respectively. Motions of the bubble interface, which can now be clearly seen with the oscillations, are indicated in high-speed photographic images. Three main frequency components and their duration are identified: reverberations of water tank, pulsations of the detonation gas bubble, and fluctuations of free water surface. Experimental results show that the reverberation concentrating in high frequencies is due to the detonation wave (DW) and reflected shock waves in the water tank; the pulsations are related to the bubble oscillating periods, which are stronger as the detonation pressure increases; and fluctuation occurs in both the bubble oscillating and floating stages. To explain the directional growth of the detonation gas bubble, an experiment of pulse detonation gas jet in air is conducted where the sudden release of detonation products behind the DW and the subsequent impulsive detonation gas jet are qualitatively presented. Results presented in this paper give in-depth analysis of pulse detonation gas jets and provide a new way to generate pulsating bubbles under water.
A hyperchaotic cycloid map with attractor topology sensitive to system parameters
Authors: Dong Chunyi , Sun Kehui , He Shaobo , Wang Huihai
Published: August 2021

We propose herein a novel discrete hyperchaotic map based on the mathematical model of a cycloid, which produces multistability and infinite equilibrium points. Numerical analysis is carried out by means of attractors, bifurcation diagrams, Lyapunov exponents, and spectral entropy complexity. Experimental results show that this cycloid map has rich dynamical characteristics including hyperchaos, various bifurcation types, and high complexity. Furthermore, the attractor topology of this map is extremely sensitive to the parameters of the map. The x--y plane of the attractor produces diverse shapes with the variation of parameters, and both the x--z and y--z planes produce a full map with good ergodicity. Moreover, the cycloid map has good resistance to parameter estimation, and digital signal processing implementation confirms its feasibility in digital circuits, indicating that the cycloid map may be used in potential applications.
Broadband X-ray generation by large krypton clusters under the effect of relativistic femtosecond laser pulses
Authors: Semenov T.A. , Ivanov K.A. , Lazarev A.V. , Tsymbalov I.N. , Volkov R.V. , Zhvaniya I.A. , Dzhidzhoev M.S. , Savel’ev A.B. , Gordienko V.M.
Published: August 2021

This paper presents a phenomenological analysis of thermodynamic parameters of a pulsed supersonic gas jet in a conical nozzle. Conditions have been found out for the condensation and formation of large krypton clusters resulting from phase transitions during adiabatic expansion of gas through the nozzle into vacuum. We have identified the phase state of the large clusters (submicron droplets consisting of ∼107 monomers) forming in the jet and obtained a high yield of X-rays from a cluster nanoplasma produced by femtosecond laser pulses of relativistic intensity I. It has been shown that, at I ≈ 3 × 1018 W cm−2, a nanoplasma consisting of large krypton clusters emits a broadband X-ray spectrum in the range 5 – 100 keV. The integrated laser to X-ray energy conversion efficiency achieved is ∼10−5 (400 nJ), and the efficiency of characteristic Kα line (12.6 keV) generation is ∼1.5 × 10−6 (68 nJ), which corresponds to a quantum yield of ∼3 × 108 photons s−1 (4π)−1, with a contrast of ∼25 relative to bremsstrahlung background.
Electron acceleration in intense laser – solid interactions at parallel incidence
Authors: Shen X.F. , Pukhov A.M. , Perevalov S.E. , Soloviev A.A.
Published: August 2021

Using multidimensional particle-in-cell simulations, we show that an electron beam with a huge space charge can be accelerated to high energies by irradiating the edge of a solid density target with an intense femtosecond laser pulse at parallel incidence. The process of energy gain of each electron is divided into two parts: the transverse laser field and the longitudinal field of the excited surface plasma wave (SPW). It is shown that the longitudinal field of the SPW dominates the acceleration of the major part of electrons. This process leads to generation of a highly collimated electron beam with a huge space charge.
Breaking of a nonlinear wake wave excited by a laser pulse during its interaction with a semi-infinite plasma
Authors: Kuznetsov S.V.
Published: August 2021

Analytical methods are used to study the properties of a wake wave excited by a relativistic laser pulse passing through a blurred boundary of a homogeneous plasma. It is found that on the plasma density plateau near its boundary, the wake wave is not regular and its phase velocity depends on the spatial coordinate. It is shown that the breaking of a wake wave is a threshold process in terms of the electron oscillation energy; the influence of the transition layer parameters on the process of wake wave breaking is determined.