bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of 7-week Resistance Training on Handcycle Performance in Able-bodied Males
Authors: Abonie Ulric Sena , Albada Tryntje , Morrien Floor , van der Woude Lucas , Hettinga Florentina
Published: August 2021

The effect of an upper body resistance training program on maximal and
submaximal handcycling performance in able-bodied males was explored.
Eighteen able-bodied men were randomly assigned to a training group (TG:
n=10) and a control group (CG: n=8). TG received 7 weeks of
upper body resistance training (60% of 1 repetition maximum (1RM),
3×10 repetitions, 6 exercise stations, 2 times per week). CG
received no training. Peak values for oxygen uptake
(V˙O2peak), power output (POpeak), heart
rate (HRpeak), minute ventilation (V˙OEpeak)
and respiratory exchange ratio (RERpeak), submaximal values (HR,
V˙O2, RER, PO, and gross mechanical efficiency (GE)),
and time to exhaustion (TTE) were determined in an incremental test pre- and
post-training. Maximal isokinetic arm strength and 1RM tests were conducted.
Ratings of perceived exertion (RPE) were assessed. A two-way repeated
measures ANOVA and post-hoc comparisons were performed to examine the effect
of time, group and its interaction (p<0.05). TG improved on
POpeak (8.55%), TTE (10.73%), and 1RM
(12.28–38.98%). RPE at the same stage during pre- and
post-test was lower during the post-test (8.17%). Despite no
improvements in V˙O2peak, training improved
POpeak, muscular strength, and TTE. Upper body resistance
training has the potential to improve handcycling performance.
Editorial
Authors: Schifferdecker-Hoch Frank , Hollmann Michael
Published: August 2021

Liebe Leserinnen und Leser,

auch in der Bewegungsförderung und der Therapie hält das Thema Digitalisierung langsam, aber sicher Einzug. Während erste Therapiemaßnahmen mit der Einführung des Digitale-Versorgung-Gesetzes und der Markteinführung der ersten DiGAs (Digitale Gesundheitsanwendungen) bereits einen digitalen Weg einschlagen, werden Abläufe vor Ort in Organisation und Therapiedurchführung vorwiegend noch mit Stift und Papier oder einfachen computergestützten Systemen gemeistert. Wie die digitale Praxis in nur wenigen Jahren aussehen kann, beschreiben Schifferdecker-Hoch et al. in ihrem Artikel.
Digitalisierung im therapeutischen Umfeld – Bestandsaufnahme und Ausblick
Authors: Schifferdecker-Hoch Frank , Droese Jens , Ayensa Jennifer Sion , Hollmann Michael
Published: August 2021

Digitalisierung hat in den letzten Jahren immer mehr Branchen erfasst. Auch das deutsche Gesundheitswesen bleibt davon nicht ausgenommen, wenngleich durch die besondere Regulatorik des deutschen Gesundheitssystems die Aufnahme von digitalen Elementen nur schleppend voran geht. Daran hat auch das Pandemiejahr nicht grundlegend etwas verändert, wie der neue Digitalindex der Initiative D 21 zeigt. Ausgehend von einer terminologischen Begriffsbestimmung zur Digitalisierung wird im Kontext des Gesundheitswesens eine Abstufung in 5 Stufen vorgeschlagen. Die Graduierung zerlegt den Komplexbegriff Digitalisierung und zeigt praxisnahe Stufen und Möglichkeiten auf. In einem darauf aufbauenden Zukunftsszenario wird eine Option der zukünftigen Inanspruchnahme eine Therapie gezeigt, von der ersten Kontaktaufnahme beim Arzt bis zur Abrechnung der Leistung in einer Praxis.
Die Videosprechstunde als Modell der Akzeptanz digitaler Leistungen im Gesundheitswesen
Authors: Hoch Paula , Arets Jana
Published: August 2021

Das Erfordernis einer flächendeckenden Gesundheitsversorgung stellt das Gesundheitswesen aktuell vor eine große Herausforderung. Genauer sollte die Digitalisierung in der Versorgungsstruktur stärker forciert werden, um dem Druck des demografischen Wandels in der Gesellschaft, der Globalisierung der Wirtschaft und des medizinisch-technischen Fortschritts standzuhalten. Doch digitale Leistungen aus dem Bereich der Telemedizin erfordern dazu die Akzeptanz auf Seiten der Patienten sowie der Ärzte als eine zentrale Voraussetzung für eine erfolgreiche Etablierung. In der vorliegenden Untersuchung wurden Patienten, die ehemals wegen Rückenschmerzen in Behandlung waren, zur Akzeptanz der Nutzung einer Videosprechstunde befragt. Mit Vorerfahrungen im beruflichen oder privaten Bereich fiel die Akzeptanz, unabhängig vom Alter der Patienten, höher aus als ohne vorherige Berührungspunkte mit digitalen Leistungen. Im Kontext der während der Befragung herrschenden Covid-19-Pandemie zeigten die Patienten dennoch eine hohe Bereitschaft zur Nutzung einer Videosprechstunde, obwohl die tatsächliche vorherige Teilnehmeranzahl an Online-Sprechstunden äußerst gering ausfiel. Zurückführbar wäre dies auf das fehlende Angebot der Ärzte, welches durch unzureichende Möglichkeiten aufgrund von einer einschränkenden rechtlichen Ausgangssituation begründet sein könnte. Die positiven Entwicklungen der letzten Jahre mit Verabschiedungen des eHealth-Gesetzes (2015) und des Digitale-Versorgung-Gesetzes (2020) können nun helfen, den Digitalisierungsprozess im deutschen Gesundheitssystem weiterzuentwickeln.
Der hybride Therapieansatz bei Hüft- und Kniearthrose: Eine Pilotstudie zu einem neuartigen Versorgungskonzept
Authors: Hirthammer Rebecca , Breitkopf Annika , Hollmann Michael , Schifferdecker-Hoch Frank
Published: August 2021

Arthrose gilt als häufigste Gelenkerkrankung, und im Hinblick auf den demografischen Wandel kann von einem weiteren Anstieg der Prävalenz ausgegangen werden. Dies bedeutet nicht nur eine Verminderung der Lebensqualität betroffener Menschen, sondern führt vor allem durch eine vermehrte Inanspruchnahme der Leistungen des Gesundheitssystems zu erheblichen volkswirtschaftlichen Kosten. Herrscht in medizinischen Leitlinien Einigkeit darüber, dass ein angepasstes Trainingsprogramm sowohl eine Schmerzreduktion erreichen als auch die Lebensqualität der Betroffenen verbessern kann, so scheinen Aufbau und Form eines Therapiekonzepts nicht klar definiert zu sein. Die vorliegende Untersuchung befasst sich daher mit den Auswirkungen einer hybriden Therapieform und versucht, diesen Ansatz als wirksames Instrument umfassend zu begründen.
Acute Cardiovascular Responses to Self-selected Intensity Exercise in Parkinson's Disease
Authors: Kanegusuku Hélcio , Cucato Gabriel Grizzo , Longano Paulo , Okamoto Erika , Piemonte Maria Elisa Pimentel , Correia Marilia Almeida , Ritti-Dias Raphael Mendes
Published: August 2021

Parkinson’s disease patients frequently present cardiovascular dysfunction. Exercise with a self-selected intensity has emerged as a new strategy for exercise prescription aiming to increase exercise adherence. Thus, the current study evaluated the acute cardiovascular responses after a session of aerobic exercise at a traditional intensity and at a self-selected intensity in Parkinson’s disease patients. Twenty patients (≥ 50 years old, Hoehn & Yahr 1–3 stages) performed 3 experimental sessions in random order: Traditional session (cycle ergometer, 25 min, 50 rpm, 60–80% maximum heart rate); Self-selected intensity: (cycle ergometer, 25 min, 50 rpm with self-selected intensity); and Control session (resting for 25 min). Before and after 30 min of intervention, brachial and central blood pressure (auscultatory method and pulse wave analysis, respectively), cardiac autonomic modulation (heart rate variability), and arterial stiffness (pulse wave analysis) were evaluated. Brachial and central systolic and diastolic blood pressure, heart rate, and the augmentation index increased after the control session, whereas no changes were observed after the exercise sessions (P<0.01). Pulse wave velocity and cardiac autonomic modulation parameters did not change after the three interventions. In conclusion, a single session of traditional intensity or self-selected intensity exercises similarly blunted the increase in brachial and central blood pressure and the augmentation index compared to a non-exercise control session in Parkinson’s disease patients.
Management of an Accidental Ingestion of a Manual Screwdriver in Implant Dentistry: A Case Report
Authors: Musu Davide , Mameli Antonello , Carreras Pierpaolo , Boero Gian Nicola
Published: August 2021

Ingestion of foreign bodies in dentistry represents an uncommon but possible event and can be life-threatening. An 82-year-old patient presented at our attention for an implant-supported rehabilitation of the maxillary arch. During the placement of the fixed prosthesis, the manual screwdriver was swallowed by the patient. From the moment of the accident, the patient did not develop any symptoms and was monitored for the following days. The instrument was not recovered within 3 days, thus a series of consecutive abdominal X-rays were performed revealing that the screwdriver was located at the level of ileocecal valve with no signs of progression. The screwdriver was removed with colonoscopy under sedation. During this treatment, a polyp was discovered and excised revealing a tubulovillous adenoma depicting low-grade dysplasia. To prevent such accidents, screwdrivers in implant dentistry should be secured with ligatures, or replaced with longer torque control wrenches.
Fracture Resistance of Teeth with Truss Endodontic Access: An In Vitro Study and Literature Review
Authors: Karobari Mohmed Isaqali , Abdul Aziz Ahmad Fareez , Makandar Saleem D. , Abdul Ghani Nik Rozainah Nik , Halim Mohamad Syahrizal , Noorani Tahir Yusuf
Published: August 2021

Objective This article evaluates the fracture resistance of teeth with different endodontic access cavities and conducts literature review on the effects of truss endodontic cavity.

Material and Methods Eighty human mandibular first molars were assigned randomly to four groups (n = 20); group 1: truss access cavity (TrussAC); group 2: conservative access cavity (ConsAC); group 3: traditional access cavity (TradAC); and group 4: served as control (no access). Accesses were prepared in groups 1 to 3, respectively. Endodontic treatment was performed on all accessed teeth and composite restoration placed. Teeth in all groups were loaded until fracture using a mechanical testing machine. The maximum load at fracture and patterns of fracture were recorded. Additionally, a literature search was performed on studies related to TrussAC and its importance.

Statistical Analysis Fracture strengths were compared using one-way analysis of variance complemented by Bonferroni test. Fracture patterns were analyzed using chi-square test.

Results TradAC showed significantly lower mean load at fracture than TrussAC, ConsAC, and intact teeth. Fracture resistance of teeth with TrussAC and ConsAC was not significantly different. All three test groups showed significantly more frequent unrestorable fractures. The literature review revealed that TrussAC did not improve the fracture strength significantly; however, pulp chamber debridement was significantly impaired.

Conclusion TrussAC improved the fracture strength of endodontically treated teeth, but not significantly as compared to ConsAC. Restorable fractures were more in intact teeth compared with all prepared ones.
Practical Aspects of Functional Magnetic Resonance Imaging in Children
Authors: Bernal Byron
Published: August 2021

Functional magnetic resonance imaging (fMRI) has become a broadly accepted presurgical mapping tool for pediatric populations with brain pathology. The aim of this article is to provide general guidelines on the pragmatic aspects of performing and processing fMRI, as well as interpreting its results across children of all age groups. Based on the author's accumulated experience of more than 20 years on this specific field, these guidelines consider many factors that include the particular physiology and anatomy of the child's brain, and how specific peculiarities may pose disadvantages or even certain advantages when performing fMRI procedures. The author carefully details the various challenges that the practitioner might face in dealing with limited volitional behavior and language comprehension of infants and small children and remedial strategies. The type and proper choice of task-based paradigms in keeping with the age and performance of the patient are discussed, as well as the appropriate selection and dosage of sedative agents and their inherent limitations. Recommendations about the scanner and settings for specific sequences are provided, as well as the required devices for appropriate stimulus delivery, response, and motion control. Practical aspects of fMRI postprocessing and quality control are discussed. Finally, given the relevance of resting-state-fMRI for use in noncooperative patients, a praxis-oriented guide to obtain, classify, and understand the spontaneous neural networks (utilizing independent component analysis) is also provided. The article concludes with a thorough discussion about the possible pitfalls at different stages of the fMRI process.
Childhood Immunoglobulin A Vasculitis Associated with COVID-19: A Case Report
Authors: Bekhit Osama E. , Alfatani Abdulelah A. , Eid Mahmoud H.R. , Mohamed Shereen A.
Published: August 2021

Primary immunoglobulin A vasculitis (IgAV) is one the most common childhood vasculitis. A 5-year and 10-month-old girl child patient presented with confluent palpable purple red rash, mainly over both ankles. This was associated with edematous, tender ankles, limited range of movement, and inability to walk. A concomitant coronavirus disease 2019 (COVID-19) was documented by nasopharyngeal swab. This case suggested that COVID-19 can trigger IgAV in children. Hence, awareness of COVID-19 infection in IgAV should be present, and it may be useful to investigate COVID-19 as one of the causes of IgAV, especially in the presence of an epidemic.
Vascularized Bone Grafting in the Treatment of Scaphoid Nonunion: A Clinical and Functional Outcome Study
Authors: Çolak İlker , Akgün Emrecan , Kılıç Zülfü , Özel Murat
Published: August 2021

Background A malreduction or missed scaphoid fracture may lead to nonunion or avascular necrosis (AVN). The aim of this study was to analyze the radiological and clinical outcome of patients with scaphoid nonunion (SN), who were treated with 1,2-intercompartmental supraretinacular artery pedicled vascularized bone graft (1,2-ICSRA-VBG) fixed with K-wires or screws between 2014 and 2018.

Methods Radiological assessment included posteroanterior, lateral, oblique, and angled posteroanterior projection. The wrist active joint range of motion was assessed with a universal goniometer, and grip and pinch strength with a dynamometer. The disabilities of the arm, shoulder and hand (DASH) questionnaire was used to evaluate functionality. Statistical analysis was performed using SPSS software (v16.0).

Results A total of 68 patients (65 male) with a mean age 29.7 ± 8.5 years were evaluated in the study, and union was achieved in 55 (81%). A total of 45 (66%) patients had scaphoid waist fracture and 48 (71%) had AVN. Fixation was achieved with K-wires in 48 of the patients, and with screw in 20. The mean length of follow-up was 31.6 ± 14.6 (12–72) months. The mean radioulnar range of motion and DASH scores improved significantly after treatment (p < 0.001, p ≤ 0.001).

Conclusions The findings of this study showed that scaphoid unions can be treated successfully with high rates of union using the 1,2-ICSRA-VBG. This surgical technique requires special surgical experience. The functional outcome of patients improved after treatment, although smoking was found to be an important factor affecting functional results.
A chemical kinetics perspective on thermoelectric transport
Authors: Chen Nan (Louise) , Pino Juan , Katz Howard E.
Published: August 2021

There is a growing community of chemists and materials scientists exploring thermoelectric properties of organic, polymeric, hybrid, and composite materials. Many of these materials are nondegenerate semiconductors, meaning that the Fermi and transport charge transport energy levels are significantly offset. Others are ionic conductors. While the meaning of the essential parameters, namely, electrical conductivity (σ) and Seebeck coefficient (S, the voltage difference per degree of temperature difference) are accessible, the origins of S are not readily apparent to one trained mainly in chemistry. The purpose of this manuscript is to illustrate S as being the result of a steady state difference between concentrations of two designations of charge carriers, those on hotter and those on colder sides of a material sample, analogous to the equilibrium among interconverting chemical species that differ in enthalpy and entropy. The ion-based Seebeck coefficient, also known as the Soret effect, can be explained using principles similar to those applicable to electrons and holes. We hope that this analysis leads to wider understanding of the origins of S through an explanation using the language of chemical kinetics and thermodynamics and appreciation of ways that thermoelectric efficiency can be enhanced in emerging materials.
Light extraction in tandem organic light emitting diodes
Authors: Fu Xiangyu , Yin Shichen , Chen Yi-An , Zhu Liping , Dong Qi , Chang Chih-Hao , So Franky
Published: August 2021

Since the invention of organic light emitting diodes (OLEDs), great research efforts have been dedicated to improving their efficiency and lifetime. For high-brightness applications, tandem OLED structures have advantages because of the lower current densities required to achieve high brightness. With the successful development of highly efficient charge generation layers, high brightness tandem OLEDs are used in displays and lighting. However, the major challenge for tandem OLEDs is the low light extraction efficiency, because about 50% of the light is trapped inside the device as waveguide modes. In this Perspective, we first review the recent works done on light extraction, analyze different waveguide mode extraction structures, and then identify the key factors determining the extraction efficiencies in tandem OLEDs.
Effective Néel relaxation time constant and intrinsic dipolar magnetism in a multicore magnetic nanoparticle system
Authors: Trisnanto Suko Bagus , Takemura Yasushi
Published: August 2021

The coexisting Néel and Brownian relaxation behaviors of magnetic nanoclusters in a viscous medium lead to a highly nonlinear field-dependent magnetization response, which can benefit magnetic particle imaging and hyperthermia. To empirically correlate the moment and particle dynamics with the core and cluster sizes, we performed spectroscopic susceptometry to assess frequency-dependent complex magnetic susceptibility of water-dispersed magnetic nanoclusters at very low field amplitude. The superparamagnetic core particles of nanoclusters should undergo fast moment dynamics. However, for the nanoclusters experiencing the field-driven Brownian relaxation, their constituent core particles appear to collectively behave as a large effective core with a long Néel relaxation time constant. We later numerically interpolated the phase-delay spectra of the immobilized nanoclusters to estimate the Néel relaxation time constant attributed to the intrinsic dipolar interparticle magnetism. From additional static magnetometry, the overlapping bimodal magnetic moment distribution predicts the secondary core sizes larger than the actual sizes from the electron microscopy images. The different estimates of the effective Néel relaxation time constant obtained from the (nearly field-free) frequency-dependent and (static) field-dependent magnetization responses further indicate the activation energies limiting the relaxation behavior of magnetic nanoclusters. This finding highlights the number of effective cores affecting the intracluster interaction energy.
Tethered-particle model: The calculation of free energies for hard-sphere systems
Authors: Moir Craig , Lue Leo , Bannerman Marcus N.
Published: August 2021

Two methods for computing the entropy of hard-sphere systems using a spherical tether model are explored, which allow the efficient use of event-driven molecular-dynamics simulations. An intuitive derivation is given, which relates the rate of particle collisions, either between two particles or between a particle and its respective tether, to an associated hypersurface area, which bounds the system’s accessible configurational phase space. Integrating the particle–particle collision rates with respect to the sphere diameter (or, equivalently, density) or the particle–tether collision rates with respect to the tether length then directly determines the volume of accessible phase space and, therefore, the system entropy. The approach is general and can be used for any system composed of particles interacting with discrete potentials in fluid, solid, or glassy states. The entropies calculated for the liquid and crystalline hard-sphere states using these methods are found to agree closely with the current best estimates in the literature, demonstrating the accuracy of the approach.
A novel higher order compact-immersed interface approach for elliptic problems
Authors: Singhal Raghav , Kalita Jiten C.
Published: August 2021

We present a new higher-order accurate finite difference explicit jump Immersed Interface Method for solving two-dimensional elliptic problems with singular source and discontinuous coefficients in the irregular region on a compact Cartesian mesh. We propose a new strategy for discretizing the solution at irregular points on a nine-point compact stencil such that the higher-order compactness is maintained throughout the whole computational domain. The scheme is employed to solve four problems embedded with circular- and star-shaped interfaces in a rectangular region having analytical solutions and varied discontinuities across the interface in source and the coefficient terms. We also simulate a plethora of fluid flow problems past bluff bodies in complex flow situations which are governed by the Navier–Stokes equations; they include problems involving multiple bodies immersed in the flow as well. In the process, we show the superiority of the proposed strategy over the explicit jump finite difference immersed interface method and other existing immersed interface methods by establishing the rate of convergence and grid independence of the computed solutions. In all the cases, our computed results are extremely close to the available numerical and experimental results.
Deep levels related to the carbon antisite–vacancy pair in 4H-SiC
Authors: Nakane Hiroki , Kato Masashi , Ohkouchi Yutaro , Trinh Xuan Thang , Ivanov Ivan G. , Ohshima Takeshi , Son Nguyen Tien
Published: August 2021

Photo-induced current transient spectroscopy (PICTS) and electron paramagnetic resonance (EPR) are used to study irradiation-induced defects in high-purity semi-insulating (HPSI) 4H-SiC. Several deep levels with the ionization energy ranging from 0.1 to ∼1.1 eV have been observed in irradiated and annealed samples by PICTS. Among these, two deep levels, labeled E370 and E700 at ∼0.72 and ∼1.07 eV below the conduction band, respectively, are detected after high-temperature annealing. The appearance and disappearance of these two deep levels and the EPR signal of the positive C antisite–vacancy pair (CSiVC+) in the sample annealed at 1000 and 1200 °C, respectively, are well correlated. Based on data from PICTS and EPR and the energies predicted by previous calculations for different charge states of dominant intrinsic defects, the E370 and E700 levels are suggested to be related to the charge transition levels (0|–) and (+|0), respectively, of the C antisite–vacancy pair. The activation energy of Ea ∼ 1.1 eV in commercial HPSI 4H-SiC materials is, therefore, reassigned to be related to the single donor (+|0) level of CSiVC.
Einstein–Rosen waves and the Geroch group
Authors: Penna Robert F.
Published: August 2021

Under the action of the Geroch group, the Minkowski metric can be transformed into any vacuum metric with two commuting Killing vectors. In principle, this reduces the problem of deriving vacuum metrics with two commuting Killing vectors to pure algebra. In this article, we use these facts to give a purely algebraic derivation of the Einstein–Rosen metric, which describes a cylindrical gravitational wave. Our derivation has a straightforward extension to gravitational pulse waves.
Investigation of effects of plasma sheath on antenna radiation based on ray tracing method
Authors: Guo Linjing , Guo Lixin , Gan Liping
Published: August 2021

The reason for communication blackout in hypersonic vehicles is strong interference from the plasma sheath on antenna radiation. This paper presents the calculation of the effects of a plasma sheath on microstrip antenna radiation using the ray tracing method, a method comprising an accurate and complex theoretical algorithm. Using an integrated model of a plasma sheath and microstrip antenna, the ray tracing method is used to obtain the disturbed electric field in the sheath with different parameters. This study reveals that the sensitivity of X-band antenna radiation to the alteration of plasma parameters is lower than that of C-band antenna radiation. These numerical results provide a reference guide for the design of antennas for use in hypersonic vehicles.
Self-limited nanosecond laser-induced bubble growth in sealed containers
Authors: Ebrahimi Orimi Hamid , Arreaza Leonardo , Narayanswamy Sivakumar , Boutopoulos Christos
Published: August 2021

We demonstrate that nanosecond laser-induced bubbles, generated in sealed containers, can experience self-limiting effects. We experimentally study such effects using simultaneous pressure and bubble dynamics recordings. We show that self-limiting effects can be drastic for mm-sized bubbles generated in sub-cm3 sized containers, resulting in 0.5-fold decrease in their size and fourfold decrease in their lifetime compared to those generated in non-sealed control containers. We use the Keller–Miksis equation to model self-limiting effects and discuss their technological implications in applications that exploit bubble growth in confined geometries.
Increased plasmin-mediated proteolysis of L1CAM in a mouse model of idiopathic normal pressure hydrocephalus
Authors: Yang Dejun , Yang Hongwei , Luiselli Gabrielle , Ogagan Charles , Dai Huijun , Chiu Lucinda , Carroll Rona S. , Johnson Mark D.
Published: August 2021

Significance

Idiopathic normal pressure hydrocephalus (iNPH) is the most common form of adult-onset hydrocephalus, but its etiology is poorly understood. Symptoms develop in previously normal individuals and include gait difficulty, incontinence, and dementia. We recently reported that 15% of iNPH patients harbor heterozygous loss-of-function deletions in CWH43, which encodes a protein that modifies other cell membrane proteins. Mice harboring CWH43 deletions develop hydrocephalus and gait dysfunction. Mutations affecting the L1CAM adhesion protein cause developmental brain abnormalities and hydrocephalus from birth. Here, we show that CWH43 deletion leads to L1CAM hypoglycosylation, decreased L1CAM association with lipid microdomains, increased plasmin-mediated L1CAM cleavage, and decreased L1CAM expression. Thus, decreased L1CAM expression appears to occur in adult-onset iNPH and congenital hydrocephalus.
A tomato LATERAL ORGAN BOUNDARIES transcription factor,
SlLOB1
, predominantly regulates cell wall and softening components of ripening
Authors: Shi Yanna , Vrebalov Julia , Zheng Hui , Xu Yimin , Yin Xueren , Liu Wenli , Liu Zimeng , Sorensen Iben , Su Guanqing , Ma Qiyue , Evanich Daniel , Rose Jocelyn K. C. , Fei Zhangjun , Van Eck Joyce , Thannhauser Theodore , Chen Kunsong , Giovannoni James J.
Published: August 2021

Significance

A tomato fruit ripening–specific transcription factor,
SlLOB1
predominantly influences fruit cell wall–related gene regulation and textural changes during fruit maturation and thus is distinct from broadly acting ripening transcription factors described to date that influence many ripening processes. As such,
SlLOB1
is an intermediate regulator primarily influencing a physiological subdomain of the overall ripening transition.
Wheat value chains in Malawi: trends, gaps, challenges and opportunities
Authors: Guwela Veronica F. , Maliro Moses F.A. , Joy Edward J.M. , Tang Kevin , Bokosi James , Hawkesford Malcolm J. , Broadley Martin R. , King Julie
Published: August 2021

Wheat (
Tritcum aestivum
L.) is an important cereal crop, consumed by over 2.5 billion people globally. The current demand for wheat in Malawi is estimated to be 200,000 tonnes/year with a projected growth in consumption of 3%–6% annually. We reviewed literature and databases on wheat production, imports, processing and consumption to describe current wheat value chains in Malawi, and to identify possible future economic and food security opportunities. The current gap between the supply and demand of wheat in Malawi is large with 99% imported due to low domestic production. The main actors in the value chain include importers, millers, bakeries, biscuit manufacturers, wholesalers and retailers. In total, 45% of milled flour is utilised by commercial bakeries, 46% is distributed to rural and urban outlets and biscuit manufacturers utilise 9%. Although there is no information on wheat exports between 2016 and 2019, FAOSTAT crop database and the ITC Trade Map databases show small quantities of wheat flour exports prior to 2016. Production constraints include the lack of a national wheat development strategy, lack of stable markets, unavailability of improved varieties, low input use and limited knowledge in the management of wheat crop. Currency devaluation and limited forex reserves further affect the annual import volumes and prices of wheat flour on the domestic market. We conclude that domestic production and wider value chain opportunities could be increased through policy support, including research for development, expansion of production into non-traditional wheat growing areas, investing in irrigation and developing market systems.
Modulation of dynamics in a pre-existing hippocampal network by neural stem cells on a microelectrode array
Authors: Moriya Fumika , Shimba Kenta , Kotani Kiyoshi , Jimbo Yasuhiko
Published: August 2021

Objective. Neural stem cells (NSCs) are continuously produced throughout life in the hippocampus, which is a vital structure for learning and memory. NSCs in the brain incorporate into the functional hippocampal circuits and contribute to processing information. However, little is known about the mechanisms of NSCs’ activity in a pre-existing neuronal network. Here, we investigate the role of NSCs in the neuronal activity of a pre-existing hippocampal in vitro network grown on microelectrode arrays. Approach. We assessed the change in internal dynamics of the network by additional NSCs based on spontaneous activity. We also evaluated the networks’ ability to discriminate between different input patterns by measuring evoked activity in response to external inputs. Main results. Analysis of spontaneous activity revealed that additional NSCs prolonged network bursts with longer intervals, generated a lower number of initiating patterns, and decreased synchronization among neurons. Moreover, the network with NSCs showed higher synchronicity in close connections among neurons responding to external inputs and a larger difference in spike counts and cross-correlations during evoked response between two different inputs. Taken together, our results suggested that NSCs alter the internal dynamics of the pre-existing hippocampal network and produce more specific responses to external inputs, thus enhancing the ability of the network to differentiate two different inputs. Significance. We demonstrated that NSCs improve the ability to distinguish external inputs by modulating the internal dynamics of a pre-existing network in a hippocampal culture. Our results provide novel insights into the relationship between NSCs and learning and memory.
Synthesis of a new phosphorus-nitrogen flame retardant and its application to polypropylene
Authors: Jinfeng Li , Wei Jiang
Published: August 2021

a new halogen-free phosphorus-nitrogen flame retardant (FR) was synthesized from triethylenetetramine, phosphorous acid, urea and other raw materials. Thermogravimetric(TG) analysis suggested that FR had good thermal stability, there was still 16.3% carbon residue at 800 °C. When the content of FR is 30%, the LOI of flame retardant composites (FR-PP) is improved from 18.0% to 25.4%, reaching the V-0 level of UL-94. SEM(Scanning electron microscope) and EDS (Energy dispersive spectrometer) results indicated that FR was successfully put on PP. The mechanical test showed that the tensile strength of FR-PP decreased from 20.8MPa to 13.1MPa, and the notched impact strength decreased from 34.5kJ/m2 to 31.6kJ/m2.
Dynamic Tunable Plasma-Induced Transparency of Periodic Images Of Graphene Nanoribbons
Authors: Xie Hanbin
Published: August 2021

Metamaterials are synthetic special structural units, usually in the wavelength or subwavelength range. When the incident light is coupled with the structural element, the free electrons on the surface can generate surface plasmons under the periodic drive of electromagnetic wave. In this paper, we mainly study the transparency of dynamically adjustable plasma-induced periodic graphical graphene nanoribbons. This paper discusses the geometric parameters that affect the variation of PIT. The gap distance G and the disc moving distance S can change the coupling strength of the light and dark modes, and the variation of coupling strength can adjust the transparency and frequency band width of PIT window. The Fermi energy of graphene can be changed by adjusting the electrical conductivity of graphene, and the change of Fermi energy can also regulate the PIT effect.
Research on the Influence of 3D Printing Speed of External Special-Shaped Parts
Authors: Lianghua Zeng
Published: August 2021

In view of the current situation that traditional processing methods are difficult to manufacture external special-shaped parts, and combined with the advantages of 3D printing technology, the thesis conducts a research on the 3D printing speed of external special-shaped parts. According to the elements of the two-dimensional cross-sectional profile, a four-jaw part model with certain structural characteristics is designed. In the experiment, the effect of changing the printing speed on the printing accuracy is discussed. Using the two-dimensional measurement method, the size and error rate of the size error at different printing speeds are calculated. The research is carried out on the basis of experiments, and a certain theoretical analysis is carried out on the experimental results, which can provide a certain reference for the 3D printing research of special-shaped parts.
Study on the Preparation of Al2O3/Al-15Si-4Mg composite material
Authors: Zhao Yingfan , Yan Zelin , Li Tieshuai , Gao Jing , Tong Weiping
Published: August 2021

In this research, microstructure refinement treatment was carried out by adding different content of lanthanum to Al-15Si-4Mg alloy. The effect of heat treatment process on the alloy after metamorphism was studied, and the optimal performance matrix was selected for A12O3/Al composite research. The results show that La has good metamorphism effect on Al-15Si-4Mg alloy. With the increase of La metamorphic agent content, the eutectic silicon structure was obviously refined. When the La content reached 1wt.%, the refining effect was the best. The hardness of the alloy was 111HBS. When the optimum amount of La was 1wt.%, the XRD phase and EDS spectrum analysis show that the alloy without modification was mainly composed of Al, Si and Mg2Si, and the metamorphic alloy also forms a rich La phase. The mechanical properties can be significant improved by the heat treatment process. After the heat treatment, the acicular structure of the eutectic silicon structure became smooth and smooth, which reduced the splitting effect on the aluminum matrix. The hardness was 113HBS. The toughness of the material can be significantly improved by the heat treatment process. The sample with 1wt.% La was selected as the matrix of the A12O3/Al composite. A12O3 Al was prepared by liquid sintering method and no rich La phase but MgAl2O4 was found near the interface which is well reactivate wetted.
Effect of Fe Content on the Microstructure and Properties of Hot-extruded 6061 Aluminum Alloy
Authors: Wu Yanda , Wang Hongfei , Ban Chunyan
Published: August 2021

The effect of Fe content on the microstructure and properties of Hot-extruded 6061 aluminum alloy was investigated. The results show that the recrystallization process can be effectively inhibited by increasing Fe content appropriately, and consequently affect the grain refinement. After hot extrusion, the iron-rich phase in 6061 aluminum alloy was broken, and fragmented phases are distributed along extrusion direction. After T4 and T6 heat treatment, a large amount of fragmented α-Al(FeMnCr)Si and Mg2Si phases are distributed for the sample with 0.3% content of Fe element. After T6 treatment, the yield strength, tensile strength and elongation of the 0.3%Fe-contenting sample are 298.95MPa, 337.43MPa and 17.88%, respectively. Compared with the hot extruded sample, its tensile strength is significantly increased, about 74.1%, but without noticeable sacrifice of its elongation.
Study on the preparation technology and high temperature oxidation characteristics of SiB4 powders
Authors: Jing Yang , Junyou Chen , Min Zhou , Yanyun Zhao , Qingmeng Zhang
Published: August 2021

High purity SiB4 powder is the key raw materials for high temperature resistant coating of rigid ceramic insulating tile, which plays the role of forming a dense coating and self-healing in the coating. Therefore, to obtain SiB4 powders with high performance and high purity at the same time can solve the problem of raw materials for high temperature resistant coating in China. However, the preparation process of SiB4 powder is complex, and no domestic manufacturer can produce it, which greatly limits the development of related industries in China. The relationship between SiB4 phase purity and boron-silicon ratio of raw materials, particle size and sintering process parameters in the synthesis of high-purity SiB4 powders was explored. The experimental results show that the yield of SiB4 can be significantly improved and the decomposition of SiB4 can be inhibited by adjusting the crystallinity of boron powder, particle size of raw material, sintering process parameters and the ratio of boron to silicon. When 1μm boron powder and 1μm silicon powder are used, the ratio of boron to silicon is 3.5:1, and the sintering process is 1320 °C - 2h, the high purity sib4 powder with only SiB4 phase detected by XRD phase analysis can be prepared after acid washing. On this basis, the high temperature oxidation characteristics of the prepared SiB4 powder were studied. The experimental results show that SiB4 powder can be oxidized at 1100 °C to form B2O3-SiO2 glass phase, which proves that it has better high temperature oxidation performance. In conclusion, it was proved that the prepared SiB4 powder had high purity and excellent high temperature resistance, which could be used for further production research.
Development and application of ZDY4300LF narrow split drilling rig
Authors: Yanjie LONG
Published: August 2021

The inconvenient drilling rig relocation, stabilization and azimuth adjustment lead to many problems in the construction of gas drainage drilling in narrow roadway, such as long auxiliary time, labor intensity of workers, low comprehensive drilling efficiency. Through the innovative layout, the power unit and the drilling unit are respectively arranged on two crawlers, and the ZDY4300LF narrow-body split crawler drilling rig is developed. The drilling rig adopts a modular design idea, Arranged the pump station and console on the pump truck. The feed revolving device and the stabilizing device are arranged on the drill carriage. The drilling rig and the pumping station are connected by high-pressure hoses. When drilling for gas drainage, the location of the drilling rig and pump truck can be arranged according to the terrain conditions to obtain the best orientation for the drilling construction. The industrial test of the drilling rig shows that the ZDY4300LF narrow-body split crawler drilling rig has the characteristics of compact structure, convenient operation, and convenient moving and relocation, which can solve the problem of gas drainage in narrow tunnels in underground coal mines. Industrial test of drilling rig shows that ZDY4300LF narrow split crawler drill has the characteristics of compact structure, convenient operation, convenient moving and moving, etc.
Finite Element Simulation of the Cooling Process of H-shaped Steel after Circular Nozzle Impinging
Authors: Zhiyu Gao , Jianzhong Xu
Published: August 2021

ANSYS fluent, a finite element numerical simulation software, was used to establish a three-dimensional model of the H-shaped steel web under the impinging impact of nozzle jet. A numerical stimulation analysis was conducted on the mode of water flow and the heat transfer of the H-shaped steel web. In the model, the finite volume method was used to discretize the model into a tetrahedral unstructured grid, the multi-flow VOF model and the achievable K-e model were used to solve the Reynolds average N-S equation, and the numerical solution method adopted the PISO algorithm. This paper aims to calculate the heat transfer performance of the ultra-fast cooling process of the H-shaped steel web under different boundary conditions, as well as explore the influence of impinging time on the distribution of water volume and temperature fields of the web by simulating the cooling process of H-shaped steel web with circular nozzle jet.
Extraction of centerline of large-format laser stripes against ambient light interference
Authors: Jun WANG , Wei CHENG , Wen-Long LI , Yi-guang Zhang
Published: August 2021

In order to carry out real-time 3D reconstruction of large components in the outdoor environment, this paper proposes a laser stripe centerline extraction algorithm that is resistant to ambient light interference. The median filter is used to preprocess the laser stripe to be extracted, and the Rosenfeld thinning and least square fitting algorithm are organically combined to extract the centerline of the laser stripe. Experimental results show that this method can effectively avoid strong light interference and accurately obtain the centerline of the laser stripe to be extracted.
Effect of Cr on Corrosion Performance of Steel Bar in Chloride Environment
Authors: Wang Baoshan , Zhang Hongliang , Liu Xin , Ma Jian , Feng Guanghong
Published: August 2021

In this article, microscopy observations, thermodynamic calculation and dry–wet cyclic corrosion test were carried out, and microstructure, properties and corrosion resistance of high strength rebar with different amounts of Cr were studied. The results show that Cr addition restrains the pearlite transformation and increases the phase change temperature range of bainite, and the Cr-contain rebars show higher pitting corrosion resistance. When the Cr content is in the range of 1–3.5%, the Cr-contain rebars show better corrosion resistance than Cr-free steel in the beginning of corrosion and the corrosion resistance is correlated positively with Cr content. As the corrosion time going, Cr-contain rebars have high corrosion rate than Cr-free steel and corrosion rate is also correlated positively with Cr content.
Experimental Research on 3D Printing Process of Square Hole
Authors: Lianghua Zeng , Lin Li
Published: August 2021

The paper designs a square hole model and uses a delta3D printer to carry out printing experiments with different process parameters. It mainly conducts experimental research on four process parameters, including printing speed, layer thickness, filling density and platform temperature. The paper carries out the analysis of the influence of process parameters on the external dimensions of the hole, the inner depth of the hole, etc., and graspes the law of the influence of different process parameters on various sizes in order to provide a certain reference for the research of the 3D printing process of special parts.
Effect of B element on Fe-10Cr-B alloy
Authors: Gao Jing , Zhao Yingfan , Tong Weiping , Chen Chu , Zhu Lin
Published: August 2021

In this paper, Fe-10Cr-B alloys with different B content were prepared by the method of liquid phase sintering. Optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), Rockwell hardness tester were used to investigate the influence of B element on the structure, phases and macro-hardness of the Fe-10Cr-B alloys. The results show that the hardness of alloys with different B content gradually increases with the increase of B content in the alloy. When the B content is 2.5 wt.%, the hardness of the alloy reaches the maximum value of 61.8HRC. A further increase in the B content will lead to a decrease in the macroscopic hardness of the alloy sample. The alloy with B content of 2.5wt.% is mainly composed of metal matrix and M23 (C, B)6 boron-carbides. The Cr and B elements are mainly enriched in boron-carbides.
Tribological behavior of WC-4.32MgO-3.68B2O3 composite
Authors: Lai Jiaming , Li Jingmao , Zhu Dezhi , Liang Liang , Qu Shengguan , Li Huiyun , Li Xiaoqiang
Published: August 2021

WC-4.32MgO-3.68B2O3 composite material was prepared by Spark plasma sintering technology, and then Si3N4 ball was used as the counter-grinding material to study the friction and wear behavior under different loading conditions by means of fretting friction. The research results show that: the distribution of the second phase has a significant effect on the wear behavior of the composites. During the fretting friction process, second phase particles peeled off from the structure, causing the abrasion of the matrix to increase. The research found that with gradually increase of the load, the friction coefficient of the material gradually decreases, but the degree of wear gradually increases. The number of furrows also increased significantly, which was related to the wear degree of convex on the surface of the materials. It can be observed from the wear scar that the main wear mechanisms of composite materials are abrasive wear and oxidative wear.
Structure and function of one-dimensional two-way pneumatic flexible bending joint
Authors: Wang X , Geng D X , Zhang L Z , Sun G D , Xu W Z , Wang P
Published: August 2021

In order to solve the problems of comprehensive flexibility of robot arm, and expand the application field of service robot and improve the safety, a one-dimensional two-way flexible bending joint is developed by using the self-developed pneumatic artificial muscle. The relevant theoretical model is established and the relevant experimental analysis is carried out. The experimental results show that the bending joint can realize one-dimensional two-way bending motion and the bending angle of the joint can be controlled by adjusting the gas pressure; when the air pressure difference between the two sides of the leaf spring is 0.22Mpa, the maximum bending angle of the joint reaches 74.12 degrees; the forward and reverse bending of the joint are consistent, and the joint bending curve is similar to the arc.
Discussion and analysis on corrosion causes of metallic components used in transmission tower
Authors: Hao Chen , Wentao Tian , Yang Guo , Zhihao Zhang , Haolun Bai
Published: August 2021

With the rapid development of power grid and the continuous aggravation of heavy industry pollution, more and more attention would be paid to the corrosion of metallic components of transmission line. The chemical and electrochemical corrosion of transmission tower and its fittings would shorten the service life. Therefore, it requires regular anti-corrosion coating treatment or even overall replacement, which not only wastes a lot of financial and material resources, but also causes safety accidents. In this paper, different testing methods such as macro inspection, metallographic analysis and energy spectrum analysis were adopt to investigat and analyse corrosion behaviour of cotter pin, fitting, guyed rod and angle steel used in transmission tower. Additionally, corresponding anti-corrosion measures were put forward in order to improve the anti-corrosion performance of the metallic components and guarantee the safety and stability of transmission line.