bluuebunny/crossref_metadata_2025 huggingface dataset:
SSVEP phase synchronies and propagation during repetitive visual stimulation at high frequencies
Authors: Tsoneva Tsvetomira , Garcia-Molina Gary , Desain Peter
Published: March 2021

Steady-state visual evoked potentials (SSVEPs), the brain response to visual flicker stimulation, have proven beneficial in both research and clinical applications. Despite the practical advantages of stimulation at high frequencies in terms of visual comfort and safety, high frequency-SSVEPs have not received enough attention and little is known about the mechanisms behind their generation and propagation in time and space. In this study, we investigated the origin and propagation of SSVEPs in the gamma frequency band (40–60 Hz) by studying the dynamic properties of EEG in 32 subjects. Using low-resolution brain electromagnetic tomography (sLORETA) we identified the cortical sources involved in SSVEP generation in that frequency range to be in the primary visual cortex, Brodmann areas 17, 18 and 19 with minor contribution from sources in central and frontal sites. We investigated the SSVEP propagation as measured on the scalp in the framework of the existing theories regarding the neurophysiological mechanism through which the SSVEP spreads through the cortex. We found a progressive phase shift from posterior parieto-occipital sites over the cortex with a phase velocity of approx. 8–14 m/s and wavelength of about 21 and 24 cm. The SSVEP spatial properties appear sensitive to input frequency with higher stimulation frequencies showing a faster propagation speed.
Fascia lata packing and tension suturing for symptomatic pseudomeningocele after recurrent cervical intradural tumour resection
Authors: Xu Huanbo , Huang Yangliang , Zhong Yi , Lu Guowang
Published: March 2021

In recurrent posterior cervical intradural tumour resections, serious complications can be developed. The dural can become affected by inflammatory factors or removed during tumor resection; if cerebrospinal fluid (CSF) leakage cannot be stopped by duraplasty, artificial meninges or fascia repair, large pseudomeningocele can develop posteriorly within the soft tissue of the neck. When the pressure of the CSF cannot be maintained steadily, persistent clinical symptoms can occur, such as postural headache or central fever. Moreover, the skin can also be penetrated in a few patients even after extension of the drainage duration, lumbar cistern drainage or skin suturing, leading to the induction of life-threatening intra-cranial infections. Is there a simple and effective surgical method to address this scenario? The aim of this study was, therefore, to investigate the effectiveness of fascia lata packing and tension suturing in the treatment of symptomatic pseudomeningocele after recurrent posterior cervical intradural tumour resection. In our study, nine consecutive spinal surgery patients were recruited from January 2008 to January 2018. All pseudomeningoceles were combined with postural headache, central neurological fever or wound non-union. There were 3 cases of melanocytoma, 3 cases of nasopharyngeal carcinoma metastasis, 2 cases of breast cancer metastasis, and 1 case of spinal canal lymphadenoma. Standard patient demographics, diagnosis, post-operative symptoms, wound healing time, and the largest pre- and last follow-up pseudomeningocele area on axial MRI sections were recorded. All cases were followed-up successfully, from 12 to 24 months, with an average of 15.3 months. Our observations indicate that all wounds healed successfully. The wound union time was 20.7 days on average. After wound union, these patients became symptom free. The largest cerebrospinal fluid area on axial MRI sections improved significantly from 42.9 ± 5.01 cm2 at p re-operation to 6.6 ± 1.89 cm2 at 1 year post-operation (P < 0.05); Our data indicate that .the proposed procedure is simple, safe and effective. And more importantly, it allows rapid closure of any cerebrospinal fluid leakage pools.
Workflow towards automated segmentation of agglomerated, non-spherical particles from electron microscopy images using artificial neural networks
Authors: Rühle Bastian , Krumrey Julian Frederic , Hodoroaba Vasile-Dan
Published: March 2021

We present a workflow for obtaining fully trained artificial neural networks that can perform automatic particle segmentations of agglomerated, non-spherical nanoparticles from scanning electron microscopy images “from scratch”, without the need for large training data sets of manually annotated images. The whole process only requires about 15 min of hands-on time by a user and can typically be finished within less than 12 h when training on a single graphics card (GPU). After training, SEM image analysis can be carried out by the artificial neural network within seconds. This is achieved by using unsupervised learning for most of the training dataset generation, making heavy use of generative adversarial networks and especially unpaired image-to-image translation via cycle-consistent adversarial networks. We compare the segmentation masks obtained with our suggested workflow qualitatively and quantitatively to state-of-the-art methods using various metrics. Finally, we used the segmentation masks for automatically extracting particle size distributions from the SEM images of TiO2 particles, which were in excellent agreement with particle size distributions obtained manually but could be obtained in a fraction of the time.
First evidence for the presence of amino acid sensing mechanisms in the fish gastrointestinal tract
Authors: Calo Jessica , Blanco Ayelén M. , Comesaña Sara , Conde-Sieira Marta , Morais Sofia , Soengas José L.
Published: March 2021

This study aimed to characterize amino acid sensing systems in the gastrointestinal tract (GIT) of the carnivorous fish model species rainbow trout. We observed that the trout GIT expresses mRNAs encoding some amino acid receptors described in mammals [calcium-sensing receptor (CaSR), G protein-coupled receptor family C group 6 member A (GPRC6A), and taste receptors type 1 members 1 and 2 (T1r1, T1r2)], while others [taste receptor type 1 member 3 (T1r3) and metabotropic glutamate receptors 1 and 4 (mGlur1, mGlur4)] could not be found. Then, we characterized the response of such receptors, as well as that of intracellular signaling mechanisms, to the intragastric administration of l-leucine, l-valine, l-proline or l-glutamate. Results demonstrated that casr, gprc6a, tas1r1 and tas1r2 mRNAs are modulated by amino acids in the stomach and proximal intestine, with important differences with respect to mammals. Likewise, gut amino acid receptors triggered signaling pathways likely mediated, at least partly, by phospholipase C β3 and β4. Finally, the luminal presence of amino acids led to important changes in ghrelin, cholecystokinin, peptide YY and proglucagon mRNAs and/or protein levels. Present results offer the first set of evidence in favor of the existence of amino acid sensing mechanisms within the fish GIT.
Ultra-high rate of temperature increment from superparamagnetic nanoparticles for highly efficient hyperthermia
Authors: Lee Jae-Hyeok , Kim Bosung , Kim Yongsub , Kim Sang-Koog
Published: March 2021

The magneto-thermal effect, which represents the conversion of magnetostatic energy to heat from magnetic materials, has been spotlighted for potential therapeutic usage in hyperthermia treatments. However, the realization of its potential has been challenged owing to the limited heating from the magnetic nanoparticles. Here, we explored a new-concept of magneto-thermal modality marked by low-power-driven, fast resonant spin-excitation followed by consequent energy dissipation, which concept has yet to be realized for current hyperthermia applications. We investigated the effect of spin resonance-mediated heat dissipation using superparamagnetic Fe3O4 nanoparticles and achieved an extraordinary initial temperature increment rate of more than 150 K/s, which is a significant increase in comparison to that for the conventional magnetic heat induction of nanoparticles. This work would offer highly efficient heat generation and precision wireless controllability for realization of magnetic-hyperthermia-based medical treatment.
A common optical approach to thickness optimization in polymer and perovskite solar cells
Authors: Iakobson Olga D. , Gribkova Oxana L. , Tameev Alexey R. , Nunzi Jean-Michel
Published: March 2021

The structure of experimentally designed solar cells was optimized in terms of the photoactive layer thickness for both organic bulk heterojunction and hybrid perovskite solar cells. The photoactive layer thickness had a totally different behavior on the performance of the organic and hybrid solar cells. Analysis of the optical parameters using transfer matrix modeling within the Maxwell–Garnett effective refractive index model shows that light absorbance and exciton generation rate in the photoactive layer can be used to optimize the thickness range of the photoactive layer. Complete agreement between experimental and simulated data for solar cells with photoactive materials that have very different natures proves the validity of the proposed modeling method. The proposed simple method which is not time-consuming to implement permits to obtain a preliminary assessment of the reasonable range of layer thickness that will be needed for designing experimental samples.
The impact of pyroclastic density currents duration on humans: the case of the AD 79 eruption of Vesuvius
Authors: Dellino Pierfrancesco , Dioguardi Fabio , Isaia Roberto , Sulpizio Roberto , Mele Daniela
Published: March 2021

Pyroclastic density currents are ground hugging gas-particle flows that originate from the collapse of an eruption column or lava dome. They move away from the volcano at high speed, causing devastation. The impact is generally associated with flow dynamic pressure and temperature. Little emphasis has yet been given to flow duration, although it is emerging that the survival of people engulfed in a current strongly depends on the exposure time. The AD 79 event of Somma-Vesuvius is used here to demonstrate the impact of pyroclastic density currents on humans during an historical eruption. At Herculaneum, at the foot of the volcano, the temperature and strength of the flow were so high that survival was impossible. At Pompeii, in the distal area, we use a new model indicating that the current had low strength and low temperature, which is confirmed by the absence of signs of trauma on corpses. Under such conditions, survival should have been possible if the current lasted a few minutes or less. Instead, our calculations demonstrate a flow duration of 17 min, long enough to make lethal the breathing of ash suspended in the current. We conclude that in distal areas where the mechanical and thermal effects of a pyroclastic density currents are diminished, flow duration is the key for survival.
Influence of intra and inter species variation in chilies (Capsicum spp.) on metabolite composition of three fruit segments
Authors: Zamljen Tilen , Jakopič Jerneja , Hudina Metka , Veberič Robert , Slatnar Ana
Published: March 2021

Twenty-one different cultivars from four different species were examined. The highest dry weight was present in seeds (between 35 and 50%) and the average water content was 60%. Placenta and pericarp contained on average 86% water. Total sugars variation between species was 60%. The most concentrated in the various cultivar pericarps were ascorbic acid ranging from 368.1 to 2105.6 mg/100 g DW and citric acid ranging from 1464.3 to 9479.9 mg/100 g DW. Total phenolic content ranged from 2599.1 mg/100 DW in ‘Chilli AS- Rot’ to 7766.7 mg/100 g DW in 'Carolina Reaper'. The placenta had 23.5 times higher phenolic content than seeds. C. chinense and C. chinense × C. frutescens had 3.5 to 5 times higher capsaicinoid content compared to C. annuum and C. baccatum, with 'Carolina Reaper' having the highest content at 7334.3 mg/100 g DW and 'Chilli AS- Rot' the lowest (318.7 mg/100 g DW).
Oleoresins and naturally occurring compounds of Copaifera genus as antibacterial and antivirulence agents against periodontal pathogens
Authors: Abrão Fariza , Silva Thayná Souza , Moura Claudia L. , Ambrósio Sérgio Ricardo , Veneziani Rodrigo Cassio Sola , de Paiva Raphael E. F. , Bastos Jairo Kenupp , Martins Carlos Henrique Gomes
Published: March 2021

Invasion of periodontal tissues byPorphyromonas gingivalisandAggregatibacter actinomycetemcomitanscan be associated with aggressive forms of periodontitis. Oleoresins from different copaifera species and their compounds display various pharmacological properties. The present study evaluates the antibacterial and antivirulence activity of oleoresins obtained from different copaifera species and of ten isolated compounds against two causative agents of periodontitis. The following assays were performed: determination of the minimum inhibitory concentration (MIC), determination of the minimum bactericidal concentration (MBC), and determination of the antibiofilm activity by inhibition of biofilm formation and biofilm eradication tests. The antivirulence activity was assessed by hemagglutination,P. gingivalisArg-X and Lis-X cysteine protease inhibition assay, andA. actinomycetemcomitansleukotoxin inhibition assay. The MIC and MBC of the oleoresins and isolated compounds1,2, and3ranged from 1.59 to 50 μg/mL againstP. gingivalis(ATCC 33277) and clinical isolates and from 6.25 to 400 μg/mL againstA. actinomycetemcomitans(ATCC 43717) and clinical isolates. About the antibiofilm activity, the oleoresins and isolated compounds1,2, and3inhibited biofilm formation by at least 50% and eradicated pre-formedP. gingivalisandA. actinomycetemcomitansbiofilms in the monospecies and multispecies modes. A promising activity concerning cysteine protease and leucotoxin inhibition was also evident. In addition, molecular docking analysis was performed. The investigated oleoresins and their compounds may play an important role in the search for novel sources of agents that can act against periodontal pathogens.
Dissociable electrophysiological measures of natural language processing reveal differences in speech comprehension strategy in healthy ageing
Authors: Broderick Michael P. , Di Liberto Giovanni M. , Anderson Andrew J. , Rofes Adrià , Lalor Edmund C.
Published: March 2021

Healthy ageing leads to changes in the brain that impact upon sensory and cognitive processing. It is not fully clear how these changes affect the processing of everyday spoken language. Prediction is thought to play an important role in language comprehension, where information about upcoming words is pre-activated across multiple representational levels. However, evidence from electrophysiology suggests differences in how older and younger adults use context-based predictions, particularly at the level of semantic representation. We investigate these differences during natural speech comprehension by presenting older and younger subjects with continuous, narrative speech while recording their electroencephalogram. We use time-lagged linear regression to test how distinct computational measures of (1) semantic dissimilarity and (2) lexical surprisal are processed in the brains of both groups. Our results reveal dissociable neural correlates of these two measures that suggest differences in how younger and older adults successfully comprehend speech. Specifically, our results suggest that, while younger and older subjects both employ context-based lexical predictions, older subjects are significantly less likely to pre-activate the semantic features relating to upcoming words. Furthermore, across our group of older adults, we show that the weaker the neural signature of this semantic pre-activation mechanism, the lower a subject’s semantic verbal fluency score. We interpret these findings as prediction playing a generally reduced role at a semantic level in the brains of older listeners during speech comprehension and that these changes may be part of an overall strategy to successfully comprehend speech with reduced cognitive resources.
Prognostic value of cardiac biomarkers in COVID-19 infection
Authors: Sheth Aakash , Modi Malak , Dawson Desiree’ , Dominic Paari
Published: March 2021

Multiple Biomarkers have recently been shown to be elevated in COVID-19, a respiratory infection with multi-organ dysfunction; however, information regarding the prognostic value of cardiac biomarkers as it relates to disease severity and cardiac injury are inconsistent. The goal of this meta-analysis was to summarize the evidence regarding the prognostic relevance of cardiac biomarkers from data available in published reports. PubMed, Embase and Web of Science were searched from inception through April 2020 for studies comparing median values of cardiac biomarkers in critically ill versus non-critically ill COVID-19 patients, or patients who died versus those who survived. The weighted mean differences (WMD) and 95% confidence interval (CI) between the groups were calculated for each study and combined using a random effects meta-analysis model. The odds ratio (OR) for mortality based on cardiac injury was combined from studies reporting it. Troponin levels were significantly higher in COVID-19 patients who died or were critically ill versus those who were alive or not critically ill (WMD 0.57, 95% CI 0.43–0.70, p < 0.001). Additionally, BNP levels were also significantly higher in patients who died or were critically ill (WMD 0.45, 95% CI − 0.21–0.69, p < 0.001). Cardiac injury was independently associated with significantly increased odds of mortality (OR 6.641, 95% CI 1.26–35.1, p = 0.03). A significant difference in levels of D-dimer was seen in those who died or were critically ill. CK levels were only significantly higher in those who died versus those who were alive (WMD 0.79, 95% CI 0.25–1.33, p = 0.004). Cardiac biomarkers add prognostic value to the determination of the severity of COVID-19 and can predict mortality.
Developingin vitromodels to assess fish gill excretion of emerging contaminants
Authors: Chang Elisabeth Dohmann , Owen Stewart F. , Hogstrand Christer , Bury Nic R.
Published: March 2021

In vitrofish gill model to study the branchial efflux of emerging contaminants at ever lower concentrations in freshwater.
Energetic and electronic properties of CsPbBr3 surfaces: a first-principles study
Authors: Yang Yi , Hou Chunju , Liang Tong-Xiang
Published: March 2021

The stability phase diagrams of CsPbBr3 (100), (110) and (111) surfaces were calculated. The origin of the stability was elucidated by electronic structures.
Electron confinement meet electron delocalization: non-additivity and finite-size effects in the polarizabilities and dispersion coefficients of the fullerenes
Authors: Lao Ka Un , Yang Yan , DiStasio Robert A.
Published: March 2021

Unique dichotomy of electron confinement and delocalization yields non-additive quantum-size effects in the polarizabilities and dispersion coefficients of the fullerenes.
Design of the persistent luminescence colour of a novel Gd3−xTbxGa3Al2O12 phosphor: synthesis methods, spectroscopic properties and mechanism
Authors: Rajfur Kamila , Głuchowski Paweł
Published: March 2021

It is demonstrated that it is possible to tune the persistent luminescence color of Gd3−xTbxGa3Al2O12 phosphor by changing the Tb3+ doping level.
Silver melamine thin film as a flexible platform for SERS analysis
Authors: Nenashkina Anastasia , Koltsov Semyon , Orlova Olga Yu. , Nikitina Anna A. , Kirilenko Demid A. , Andreeva Daria V. , Blanco-Formoso Maria , Pazos-Perez Nicolas , Alvarez-Puebla Ramon , Skorb Ekaterina V.
Published: March 2021

The new SERS detection platform is applicable for the quick and easy formation of sensing devices for food, agriculture, and environmental science.
Development of an enzyme-linked immunosorbent assay for the detection of mebendazole in chicken and mutton
Authors: He Jinxin , Zheng Yan , Chen Xiaorong , Li Na , Tang Fang , Huo Nairui , Wang Jianzhong , Gu Shaopeng
Published: March 2021

Mebendazole (MBZ), a synthetic benzimidazole, is most widely used for the treatment of intestinal helminthiasis.
Enhanced water purificationviaredox interfaces created by an atomic layer deposition strategy
Authors: Huang Liming , Yan Tingting , Mahmoud Alaa El Din , Li Shuangxi , Zhang Jianping , Shi Liyi , Zhang Dengsong
Published: March 2021

Capacitive removal of metal ions from wastewater was demonstrated by using Ti–C redox interfaces created by an ALD strategy.
Monitoring the stability of aerobic granular sludge using fractal dimension analysis
Authors: Pavissich Juan Pablo , Camus Nicolás , Campos José Luis , Franchi Óscar , Pedrouso Alba , Carrera Paula , Val del Rio Ángeles , Mosquera-Corral Anuska
Published: March 2021

The variability of the fractal dimension value can be used as an indicator of the stability of aerobic granular sludge.
Effects of fungal beta-glucans on health – a systematic review of randomized controlled trials
Authors: Vlassopoulou Marigoula , Yannakoulia Mary , Pletsa Vasiliki , Zervakis Georgios I. , Kyriacou Adamantini
Published: March 2021

Oral supplementation with beta-glucans demonstrates health-promoting properties, such as the prophylactic effect against the occurrence and severity of upper respiratory tract infections, primarily through the potentiation of the immune system.
Recyclable ZnS QDs as an efficient photocatalyst for dye degradation under the UV and visible light
Authors: Juine Rabindra Nath , Sahu Binay Kumar , Das Arindam
Published: March 2021

Energy-efficient synthesized ZnS QDs with unique visible range absorption through defects show the best photocatalytic activity under UV light and best degradation under visible light.
Panchromatic aza-Bodipy based π-conjugates
Authors: Gayathri Thumuganti , Rao Ravulakollu Srinivasa , Gupta Vinay , Singh Surya Prakash
Published: March 2021

A series of three aza-Bodipy donor molecules namely Aza-Bthp, Aza-Sty, and Aza-Fhdt have been synthesized.
Quasi-static 3D structure of graphene ripple measured using aberration-corrected TEM
Authors: Segawa Yuhiro , Yamazaki Kenji , Yamasaki Jun , Gohara Kazutoshi
Published: March 2021

Our new method of measuring monolayer graphene revealed experimentally that the ripple structure was represented as a superposition of sinusoidal waves, with their wave vectors coinciding with the specific direction of the six-membered ring.
Amidino substituted 2-aminophenols: biologically important building blocks for the amidino-functionalization of 2-substituted benzoxazoles
Authors: Ptiček Lucija , Hok Lucija , Grbčić Petra , Topić Filip , Cetina Mario , Rissanen Kari , Pavelić Sandra Kraljević , Vianello Robert , Racané Livio
Published: March 2021

A new synthetic strategy involving the Pinner reaction offers various amidino-functionalized 2-substituted benzoxazolesviaamidino-substituted 2-aminophenols with sub-micromolar antiproliferative activities.
Pd-Oxazolone complexes conjugated to an engineered enzyme: improving fluorescence and catalytic properties
Authors: Garcia-Sanz Carla , Andreu Alicia , de las Rivas Blanca , Jimenez Ana I. , Pop Alexandra , Silvestru Cristian , Urriolabeitia Esteban P. , Palomo Jose M.
Published: March 2021

A very mild and selective approach to greatly improved properties of Pd oxazolones by site-incorporation on an enzyme is reported. The new Pd–enzyme conjugates were fluorescents at ppm concentrations and excellent catalysts in different reactions.
Fe2O3 enhanced high-temperature arsenic resistance of CeO2–La2O3/TiO2 catalyst for selective catalytic reduction of NOx with NH3
Authors: Wang Na , Ye Changfei , Xie Huidong , Yang Chang , Zhou Jinhong , Ge Chengmin
Published: March 2021

The NO conversion of the CeLa0.5Fe0.2/Ti is obviously better than that of the commercial vanadium-based catalyst with regard to arsenic resistance and it has good N2 selectivity, and good SO2 resistance.
Island formation of Er(trensal) single-ion magnets on graphene observed on the micrometer scale
Authors: Dreiser Jan , Wäckerlin Christian , Buzzi Michele , Pedersen Kasper S. , Bendix Jesper
Published: March 2021

The island formation of Er(trensal) single-ion molecular magnets on graphene/Ru(0001) has been studied using X-ray photoelectron emission microscopy.
Synthesis of novel seven-membered carbasugars and evaluation of their glycosidase inhibition potentials
Authors: Athiyarath Vignesh , Roy Naveen J. , Vijil A. T. V. , Sureshan Kana M.
Published: March 2021

Here, we report the synthesis of five novel seven-membered carbasugar analogs.
Total synthesis of landomycins Q and R and related core structures for exploration of the cytotoxicity and antibacterial properties
Authors: Lai Yao-Hsuan , Mondal Soumik , Su Hsin-Tzu , Huang Sheng-Cih , Wu Mine-Hsine , Huang I.-Wen , Yang Lauderdale Tsai-Ling , Song Jen-Shin , Shia Kak-Shan , Mong Kwok-Kong Tony
Published: March 2021

Herein, we report the total synthesis of landomycins Q and R as well as the aglycone core, namely anhydrolandomycinone and a related core analogue.
Query-guided protein–protein interaction inhibitor discovery
Authors: Celis Sergio , Hobor Fruzsina , James Thomas , Bartlett Gail J. , Ibarra Amaurys A. , Shoemark Deborah K. , Hegedüs Zsófia , Hetherington Kristina , Woolfson Derek N. , Sessions Richard B. , Edwards Thomas A. , Andrews David M. , Nelson Adam , Wilson Andrew J.
Published: March 2021

Small-molecule protein–protein interaction inhibitors were prioritised on the basis of shape similarity to secondary structure-based queries incorporating hot-spot residues.
Target-templated de novo design of macrocyclic d-/l-peptides: discovery of drug-like inhibitors of PD-1
Authors: Guardiola Salvador , Varese Monica , Roig Xavier , Sánchez-Navarro Macarena , García Jesús , Giralt Ernest
Published: March 2021

In silico design of heterochiral cyclic peptides that bind to a specific surface patch on the target protein (PD-1, in this case) and disrupt protein–protein interactions.
Self-organization of a 4-miktoarm star block copolymer induced by cylindrical confinement
Authors: Gupta Supriya , Chokshi Paresh
Published: March 2021

Self-consistent field calculations reveal several interesting self-assembled ordered phases of ABCD star tetrablock copolymer confined within a cylindrical nanopore.
Collaborative compromise of two-dimensional materials in sodium ion capacitors: mechanisms and designing strategies
Authors: Jiang Yingjun , Liu Zhifang , Guo Songtao , Wang Libin , Li Yaqian , Hu Xianluo
Published: March 2021

This review provides a comprehensive summary of the research progress of emerging 2D materials in sodium ion capacitors.
Commentary on: Renin–angiotensin system overactivation in perivascular adipose tissue contributes to vascular dysfunction in heart failure
Authors: Ferrario Carlos M.
Published: March 2021

We comment on the publication of a paper in which Brazilian investigators evaluate the anticontractile response of perivascular adipose tissue (PVAT) in experimental heart failure (HF) induced in rats by occlusion of a coronary artery.
Chemical supply chain coordination based on technology level and lead-time considerations
Authors: Fander Atieh , Yaghoubi Saeed , Asl-Najafi Javad
Published: March 2021

The production and transportation of chemicals is a risky process with high-cost operations for members of the supply chain, where some of the materials deteriorate over time and deal with value-reduction challenges. This paper studies a two-stage hazardous chemicals supply chain with a supplier and a manufacturer in a finite time horizon with a constant deterioration rate for both sides. To prevent potential hazards and improve product quality, the manufacturer invests in risk reduction and quality improvement technologies that can also attract more market demand. Owing to the importance of time in the storage and production of chemical products, this study focuses on a novel lead-time based discount contract to coordinate the channel members. The contract seeks to maximize the total profit of the chain by determining the optimal lead-time and manufacturer’s technology level. By doing so, the supplier provides high-quality products and the manufacturer’s unit supplying cost reduces and can buy more chemicals from the supplier. On the other hand, the supplier will have more time to supply the product and its initial cost will be reduced. As a result, the profit of both sides increases simultaneously. Some numerical examples are applied to examine the applicability of the proposed models. Finally, several sensitivity analyses on the main parameters are conducted to extract some in-depth managerial implications.
Diagnostik und Differenzialdiagnosen der nicht traumatischen Subarachnoidalblutung
Authors: Schulte-Altedorneburg Gernot
Published: March 2021

Die nicht traumatische Subarachnoidalblutung (SAB) ist meist auf die Ruptur eines intrakraniellen Aneurysmas zurückzuführen. Aber es gibt weitere, sehr unterschiedliche Erkrankungen, die mögliche Differenzialdiagnosen sind. Sie richtig zu diagnostizieren, ist alleine schon von Relevanz, weil sich Ätiologie, Behandlung, Komplikationen, Prognose und sogar die Folgebildgebung unterscheiden.
Brave New Psychiatry? Oder: Wohin führt die Künstliche Intelligenz die Psychiatrie?
Authors: Leidinger Friedrich
Published: March 2021

Ein kritischer Überblick über Publikationen zur Anwendung von „lernenden Algorithmen“ und „künstlichen neuronalen Netzen“ in der Psychiatrie führt in ein dystopisches Zukunftszenario. Dem Ansatz einer Nosologie auf molekularbiologischer Basis wird ein aus der kritischen Auseinandersetzung mit der Geschichte und im Dialog mit den Betroffenen entwickeltes ökologisches Störungskonzept der Psychiatrie gegenübergestellt.
Increasing the yield and energy of high-intensity laser-produced positrons by adding microstructures
Authors: McConnon Aili
Published: March 2021

A microwire array target with added microstructures yields a near 100% increase in the laser-to-positron conversion efficiency and a 10 MeV increase in positron energy.
A molecular-level strategy to boost the mass transport of perovskite electrocatalyst for enhanced oxygen evolution
Authors: She Sixuan , Zhu Yinlong , Tahini Hassan A. , Hu Zhiwei , Weng Shih-Chang , Wu Xinhao , Chen Yubo , Guan Daqin , Song Yufei , Dai Jie , Smith Sean C. , Wang Huanting , Zhou Wei , Shao Zongping
Published: March 2021

Perovskite oxides are of particular interest for the oxygen evolution reaction (OER) due to their high intrinsic activity. However, low surface area and nonpores in bulk phase generally limit the mass transport and thereby result in unsatisfactory mass activity. Herein, we propose a “molecular-level strategy” with the simultaneous modulation of the ordered pores on the oxygen-deficient sites along with sulfur (S) substitution on oxygen sites at the molecular level to boost the mass transport behavior of perovskite electrocatalyst for enhanced mass activity. As a proof of concept, the elaborately designed brownmillerite oxide Sr2Co1.6Fe0.4O4.8S0.2 (S-BM-SCF) shows approximately fourfold mass activity enhancement in 1 M KOH compared with the pristine SrCo0.8Fe0.2O3-δ (SCF) perovskite. Comprehensive experimental results, in combination with theoretical calculations, demonstrate that the intrinsic molecular-level pores in the brownmillerite structure can facilitate reactive hydroxyl ion (OH−) uptake into the oxygen-vacant sites and that S doping further promotes OH− adsorption by electronic structure modulation, thus accelerating mass transport rate. Meanwhile, the S-BM-SCF can significantly weaken the resistance of O2 desorption on the catalyst surface, facilitating the O2 evolution. This work deepens the understanding of how mass transport impacts the kinetics of the OER process and opens up a new avenue to design high-performance catalysts on the molecular level.
Anharmonic Raman spectra simulation of crystals from deep neural networks
Authors: Shang Honghui , Wang Haidi
Published: March 2021

Raman spectroscopy is an effective tool to analyze the structures of various materials as it provides chemical and compositional information. However, the computation demands for Raman spectra are typically significant because quantum perturbation calculations need to be performed beyond ground state calculations. This work introduces a novel route based on deep neural networks (DNNs) and density-functional perturbation theory to access anharmonic Raman spectra for extended systems. Both the dielectric susceptibility and the potential energy surface are trained using DNNs. The ab initio anharmonic vibrational Raman spectra can be reproduced well with machine learning and DNNs. Silicon and paracetamol crystals are used as showcases to demonstrate the computational efficiency.
Mode control by rearrangement of the slow wave structure in a 12-cavity relativistic magnetron with diffraction output using single-stepped cavities driven by a transparent cathode
Authors: Li Y. , Liu M. , Liu C. , Feng J. , Schamiloglu E. , Fuks M. I. , Jiang W. , Li F. , Han J. , Yang X.
Published: March 2021

We present the design of an agile slow wave structure for a “crab-like” A12 relativistic magnetron with diffraction output using single-stepped cavities. By regrouping the interaction region as three sets of four cavities, the TE31 operating mode is generated at 2.60 GHz with 1.0 GW output power for an applied voltage of U = 350 kV and a magnetic field of B = 0.34 T. By regrouping the interaction region as four sets of three cavities, the TE41 operating mode is generated at 2.82 GHz with 1.0 GW output power for an applied voltage of U = 355 kV and a magnetic field of B = 0.36 T. Furthermore, by regrouping the interaction region as six sets of two cavities, the TE31 mode and the TE21 mode are generated. When an applied voltage of U = 350 kV and a magnetic field of B = 0.33 T are used, its output power can be as high as 1.0 GW for the TE31 mode operating at 2.5 GHz. In addition, when an applied voltage of U = 350 kV and a magnetic field of B = 0.42 T are used, its output power can be as high as 1.0 GW with operating mode TE21 at 2.62 GHz. It was found that the rearrangement of the slow wave structure can control the operating mode and, at the same time, lower the operating condition of the beam/wave interaction compared to the traditional 12-cavity relativistic magnetron. The result suggests that this configuration is favorable for mode switching through mechanical rearrangement of the slow wave structure. This work seeks to design a compact high power microwave source for a narrowband directed microwave beam that is suitable for mode switching investigations.
Development of an indirect thrust stand based on a cantilever beam
Authors: Zhang H. , Li D. T. , He F. , Chen X. W.
Published: March 2021

There is a large number of missions that have been or will be launched soon that utilize the electric propulsion (EP), which is considered a key technology for applications in present and future space missions. Accomplishing an accurate measure of the thrust is a key aspect of the laboratory verification of EP systems. In the case of ground conditions and direct measurements, it is complicated to verify the thrusters, especially for some high power (>5 kW) thrusters. For this reason, we have developed an indirect method for measuring thrust. We have carried out an experiment with a Hall effect thruster (operated in the 250 W power range) and compared results against direct thrust measurements. The difficulties in the indirect measurement are analyzed, which provides a basis for the development of indirect thrust measurement.
Nonlinear interactions in a hypersonic boundary layer
Authors: Zhang Chuanhong , Shi Zhiwei
Published: March 2021

Nonlinear interactions between different disturbances in a hypersonic boundary layer are investigated by bispectral analysis. Experiments are performed on a flared cone at Mach 6 using fast-response pressure sensors and Rayleigh-scattering flow visualization. At the modal growth stage, the phase-coupled sum interactions have profound effects on the growth of the disturbances. Then, the difference interactions between different disturbances contribute to the spectral broadening. At the final stage, the nonlinear interactions between the second mode and low-frequency waves result in the stretching and deformation of the second mode, which breaks down to smaller structures rapidly and the flow transitions to turbulence.
Analyzing the magnetic interactions in nanostructures that are candidates for applications in spintronics
Authors: Holanda José
Published: March 2021

It is very common for the qualitative study of magnetic interactions in nanostructures to lead to applications in spintronics. In this paper, a model is presented to calculate the magnetic interactions in nanostructures. The model can determine quantitative values for the types of magnetic states in the sample, which can be demagnetized or magnetized. Each magnetic interaction provides information on the magnetic behavior of the nanostructure and opens possibilities for spin-wave excitations. For the model application, numerical simulations were carried out on nanostructures of type nanowires and hexagonal nanowire arrays. Each nanowire is one chain of interacting ellipsoidal grains.
The ‘dark phase’ in Sr2Ir1−x
Rh
x
O4 revealed by Seebeck and Hall measurements
Authors: Fruchter L , Brouet V
Published: March 2021

It was found that, although isovalent, Rh substituted for Ir in Sr2IrO4 may trap one electron inducing effective hole doping of Ir sites. Transport and thermoelectric measurements on Sr2Ir1−x
Rh
x
O4 single crystals presented here reveal the existence of an electron-like contribution to transport, in addition to the hole-doped one. As no electron band shows up in ARPES measurements, this points to the possibility that this hidden electron may delocalize in disordered clusters.
Low-temperature processed tantalum/niobium co-doped TiO2 electron transport layer for high-performance planar perovskite solar cells
Authors: Duan Yanyan , Zhao Gen , Liu Xiaotao , Ma Jiale , Chen Shuyao , Song Yanlin , Pi Xiaodong , Yu Xuegong , Yang Deren , Zhang Yiqiang , Guo Feng
Published: March 2021

A low-temperature preparation process is significantly important for scalable and flexible devices. However, the serious interface defects between the normally used titanium dioxide (TiO2) electron transport layer (ETL) obtained via a low-temperature method and perovskite suppress the further improvement of perovskite solar cells (PSCs). Here, we develop a facile low-temperature chemical bath method to prepare a TiO2 ETL with tantalum (Ta) and niobium (Nb) co-doping. Systematic investigations indicate that Ta/Nb co-doping could increase the conduction band level of TiO2 and could decrease the trap-state density, boosting electron injection efficiency and reducing the charge recombination between the perovskite/ETL interface. A superior power conversion efficiency of 19.44% can be achieved by a planar PSC with a Ta/Nb co-doped TiO2 ETL, which is much higher than that of pristine TiO2 (17.60%). Our achievements in this work provide new insights on low-temperature fabrication of low-cost and highly efficient PSCs.
Spin-Seebeck effect and thermal colossal magnetoresistance in the narrowest zigzag graphene nanoribbons
Authors: Wu Dan-Dan , Fu Hua-Hua
Published: March 2021

Device miniaturization and low-energy dissipation are two urgent requirements in future spintronics devices. The narrowest zigzag graphene nanoribbons (ZGNRs), which are composed of just two coupled carbon-atom chains connected with carbon tetragons, are promising candidates that meet both of the above requirements well. Using the first-principles calculations combined with non-equilibrium Green’s function approach, thermal spin-dependent transport through this kind of narrow ZGNR is investigated, and several exotic thermal spin-resolved transport properties are uncovered: (i) when an external magnetic field is applied, the ZGNRs are transited from the intrinsic semiconducting to the metallic state, and the thermal colossal magnetoresistance effect occurs with order of magnitudes up to 104 at room temperature; (ii) the thermal spin-dependent currents display a thermal negative differential resistance effect, and a well-defined spin-Seebeck effect (SSE) together with a pure thermal spin current occurs; and (iii) under suitable device temperature settings, a nearly perfect spin-filtering effect occurs in these narrowest ZGNRs. The theoretical results not only uncover the narrowest nanoribbon structures to realize the SSE and other inspiring thermal spin transport features, but also push carbon-based material candidates towards thermoelectric conversion device applications.
Controlled electron transmission by lead chalcogenide barrier potential
Authors: Pfeffer P , Zawadzki W , Dybko K
Published: March 2021

Transmission of electrons across a rectangular barrier of IV–VI semiconductor compounds is considered. Conduction electrons arrive at the barrier and are reflected or transmitted through it depending on the relative values of the barrier potential V

b
and the electron energy E. The theory, in close analogy to the Dirac four component spinors, accounts for the boundary conditions on both sides of the barrier. The calculated transmission coefficient TC
is an oscillatory function of the barrier voltage varying between zero (for full electron reflection) and unity (for full electron transmission). Character of electron wave functions outside and inside the barrier is studied. There exists a total current conservation, i.e. the sum of transmitted and reflected currents is equal to the incoming current. The transmission TC
is studied for various barrier widths and incoming electron energies. Finally, the transmission coefficient TC
is studied as a function of V

b
for decreasing energy gaps E

g
of different Pb1 − x
Sn
x
Se compounds in the range of 150 meV

⩾

E
g

⩾

2 meV. It is indicated that for very small gap values the behavior of TC
closely resembles that of the chiral electron tunneling by a barrier in monolayer graphene. For E

g
= 0 (Pb0.81Sn0.19Se) the coefficient TC
reaches the value of 1 independently of V

b
.
Optimizing autonomous thermal machines powered by energetic coherence
Authors: Hammam Kenza , Hassouni Yassine , Fazio Rosario , Manzano Gonzalo
Published: March 2021

The characterization and control of quantum effects in the performance of thermodynamic tasks may open new avenues for small thermal machines working in the nanoscale. We study the impact of coherence in the energy basis in the operation of a small thermal machine which can act either as a heat engine or as a refrigerator. We show that input coherence may enhance the machine performance and allow it to operate in otherwise forbidden regimes. Moreover, our results also indicate that, in some cases, coherence may also be detrimental, rendering optimization of particular models a crucial task for benefiting from coherence-induced enhancements.
Improving Spectrum Sensing Under Impact of Noise Uncertainty Factor to Detect Primary User Traffic for Cognitive Radio System
Authors: Wotaif Akil H. , Hamza Bashar J. , Saad Wasan Kadhim
Published: March 2021

Nowadays, users of wireless communication networks are facing a challenge and a shortage in allocating the radio spectrum, as a result of the rapid and widespread development in the wireless field. A major cause of this scarcity is the reliance on the strategy and policy of distribution or fixed allocation of the radio spectrum, as it is a natural and limited source. Cognitive radio is the best system to deal with the scarcity of the radio spectrum at the present time, as the idea of this system is to allow secondary or unauthorized users to use the spectrum in times it is not used by the primary of authorized users. This use is made conditionally without affecting the original users. The spectrum sensing function is one of the most important functions of the cognitive radio system and is the essence of its work. The traditional methods have proven ineffective in sensing and detecting the dynamic primary user, due to its assumptions that either the primary user is totally present or completely absent, as well as neglecting the reuse of the spectrum again. The main objective of this research is to suggest an algorithm to improve the detection process and reduce sensing time. The efficiency of spectrum sensing is improved through the use of a dynamic threshold. The new work in this scheme is the modeling of the primary dynamic user signal called Activity period (A) which presents a more realistic modeling and dynamic threshold together. The signal-to-noise ratio was used low to some extent, this is to ensure the quality of communication services. Consequently, the simulation results clearly prove that the proposed scheme achieves and meets the sensing enhancing requirements much better than many other sensing technologies.
Using Cucumber Plants Leaves A Cover To Hiding Encryption Text
Authors: Abdullah Ahmed Saadi , Sleman Walead Kaled , Waleed Mohammed
Published: March 2021

The article presented a way to increase the efficiency of hiding information by relying on the leaves of the cucumber plant and using it as a cover to hide the information after applying a set of digital image processing techniques to this image. As for the text to be hidden, the text is initially encrypted based on an innovative cryptographic algorithm, three criteria were used to measure The efficiency of the algorithm is psnr, mse, rmse.
An Image of Encryption Algorithm Using Graph Theory and Speech Signal Key Generation
Authors: Abduljaleel Iman Qays , Abdul-Ghani Samaher Adnan , Naji Huda Zaki
Published: March 2021

In this paper, a color image of encryption algorithm used a graph theory has been proposed. The proposed algorithm depends on the audio files as a basis for exploiting a set of keys for encoding color images. The key generation system was built by passing the audio signal in several stages based on the graph theory. The results revealed that the proposed algorithm has generated the encrypted images with uniform distribution in pixel histograms with information entropy closes to 8, which resists different attacks. The comparison experiments with other recent algorithms were performed. The statistical results show that the proposed algorithm has a strong security against attacks.
Classification of Arabic Documents depending on Maximal Frequent Itemsets
Authors: Hamid Zeyad , Khafaji Hussein K.
Published: March 2021

In this paper we introduced techniques for classifying Arabic documents depending on association rules built from maximal frequent itemsets. Parallel Maximal Itemset Miner Algorithm (PMIMA) adopted several conditions to prune search space parallelly introduced for extracting maximal frequent itemsets. Rule length, rule weight and rule majority are three classification methods exploited to classification Arabic documents. Comparing with classification results obtained depending on all frequent itemsets extracted by Apriori, we proved efficiency of ours approach.
Design and Develop an Attendance System Based on Fingerprint and Arduino Board
Authors: Abdulkadhim Ekhlas Ghaleb
Published: March 2021

The academic attendance of students largely influences their acquired knowledge, grades, and skills and is of paramount importance. The present study aimed to reinforce a fingerprint identification system to be applied in a database. Fingerprinting is an efficient and rapid technique for attendance checks as it represents the uniqueness of humans and is easily available. Fingerprint sensors have benefited from this exclusivity for the automatic identification or recognition of individuals. To this end, we designed and developed an attendance system, the main components of which were a Fingerprint reader and Arduino board (microcontroller) for the insertion of the records into the database. As a result, the performance evaluation of students was facilitated by the recorded attendance in an accurate, efficient manner with the least possible error, as the results of testing this system was with an average of 98.833 %, as well as the improved academic performance of students as they must attend all the sessions and cannot avoid classes.