bluuebunny/crossref_metadata_2025 huggingface dataset:
Piezoelectric Nanogenerators Based on Helical Carbon Materials and Polyvinyledenedifluoride–Trifluoroethylene Hybrids with Enhanced Energy‐Harvesting Performance
Authors: Han Ying , Jiang Chunli , Lin Hechun , Luo Chunhua , Qi Ruijuan , Peng Hui
Published: March 2020

The geometry of piezoelectric materials has a great impact on the output performance of piezoelectric nanogenerators (PNGs), a promising candidate for providing electricity in wireless systems. The nanohelix has been considered as a hopeful nanostructure for PNGs due to the geometrical stress confinement effect and has been demonstrated by finite element analysis. Herein, helical nanobelts of graphene/poly(vinylidenefluoride‐co‐trifluoroethylene) (PVDF–TrFE) and multiwalled carbon nanotube (MWCNT)/PVDF–TrFE hybrids are prepared using a direct‐write technique. The PNGs based on these helical nanobelts are fabricated and effectively harness mechanical energy to generate electricity. The output voltages of the PNGs based on the pure helical PVDF–TrFE, MWCNT (0.03 wt%)/PVDF–TrFE, and graphene (0.03 wt%)/PVDF–TrFE nanobelts are recorded. The average outputs of the three kinds of PVDF helical nanobelts are approximately 10.3, 11.9, and 20.7 mV, respectively. The maximum of output voltage of 35 mV is achieved using the graphene (0.005 wt%)/PVDF–TrFE nanobelts. Geometrical stress confinement is identified as a mechanism responsible for high piezoelectricity in nanostructures, rendering the helical nanogenerators potentially advantageous for efficient energy harvesting.
Effects of honeybush (Cyclopia subternata) extract on physico‐chemical, oxidative and sensory traits of typical Italian salami
Authors: Smit Paula , Cullere Marco , Dalle Zotte Antonella , Balzan Stefania , Hoffman Louwrens Christiaan , Novelli Enrico
Published: March 2020

Honeybush (Cyclopia subternata Vogel) is an indigenous South African shrub enjoyed as hot brewed tea. “Unfermented” honeybush is also a potential antioxidant bioactive extract for foodstuffs due to its polyphenol content. The effect of “unfermented” honeybush extract (Hob; 0.5%) was evaluated in typical Italian salami and compared with nitrate (Nit; 100 mg/kg) and a control (Ctl; without nitrate or honeybush). After 35 days of ripening, Hob had a higher (p < .01) water activity (0.928), compared with Ctl (0.923) and Nit (0.924). Final pH (5.35–5.24) was not affected by treatments. Lower lipid oxidation was observed in Hob and Nit treatments (p < .001) compared with Ctl. Internal color and odor intensity were similar among treatments. Salami with honeybush extract had less spontaneous outer surface mold growth whereas the Ctl showed intermediate growth (p < .05). Honeybush extract seems a promising natural ingredient with antioxidant action.
Collaborative public spaces and upgrading through global value chains: The case of Dongguan, China
Authors: Murphree Michael , Breznitz Dan
Published: March 2020

Research Summary

How do multinational enterprises (MNEs) address host‐country challenges after the initial investment? And when does foreign direct investment (FDI) result in local upgrading? Using a study of FDI and global value chain participation in Dongguan, China, we find a mechanism in which FDI results in sustained local economic upgrading and improved MNE subsidiary performance: a collaborative public space (CPS). A CPS is a social space based on trust that enables different and divided actors to engage, sharing concerns and information in ways that they otherwise would be disinclined to consider. Using the CPS concept, we expand understanding of the effectiveness of MNE strategies in host‐country environments and the conditions in which FDI leads to change in global value chains.

Managerial Summary

The international strategy literature has found that FDI has ambiguous impacts on host‐country regions and firms, leading in some cases to upgrading or in others to local firm deskilling or decline. It has also shown that the postinvestment strategies of MNEs, particularly political connections or business associations, have mixed results. Using the concept of a CPS, we show how the construction of a trust‐based social space can improve MNE subsidiary and local firm performance and lead to changes in the structure and composition of global value chains (GVC). The GVC changes by incorporating new host‐country suppliers and buyers as well as increasing the value‐added, thus creating a new node and exchange patterns in the GVC.
Detection of amastigotes and histopathological alterations in the thymus of Leishmania infantum‐infected dogs
Authors: da Silva Aurea V. A. , de Souza Tainã L. , Figueiredo Fabiano B. , Mendes Artur A. V. , Ferreira Luiz C. , Filgueira Camila P. B. , Cuervo Patricia , Porrozzi Renato , Menezes Rodrigo C. , Morgado Fernanda N.
Published: March 2020

Introduction

In canine visceral leishmaniasis (CVL), lymphopenia, and the disorganization of lymphoid organs such as spleen and lymph nodes have been demonstrated. However, the involvement of thymus in CVL has not been evaluated so far. Herein, we investigated whether the thymus can be colonized by Leishmania infantum in naturally infected dogs.

Methods

Thymus were obtained from 16 of 58 dogs and samples of this organ were submitted to immunohistochemistry for laminin and fibronectin detection, histopathology, in situ hybridization and polymerase chain reaction (PCR) targeting the gene ITS‐1 for Leishmania and sequenced. Samples of spleen, skin and popliteal lymph nodes were collected and submitted to immunohistochemistry and parasitological culture followed by multilocus enzyme electrophoresis.

Results

L. infantum was identified in all dogs. DNA and amastigote forms of Leishmania were detected in the thymus from 16 dogs by PCR and in eight by immunohistochemistry. Besides thymus, parasites were detected in spleen, lymph nodes, and skin. A granulomatous or pyogranulomatous thymitis was observed in eight dogs associated to intact amastigotes forms of this parasite. Fibronectin deposition in thymus was higher in dogs with more clinical signs.

Conclusions

These results demonstrate that the thymus of dogs can be parasitized by L. infantum, which may generate inflammatory reactions leading to alterations in thymic microarchitecture.
Human and Arabidopsis alpha‐ketoglutarate‐dependent dioxygenase homolog proteins—New players in important regulatory processes
Authors: Marcinkowski Michał , Pilžys Tomaš , Garbicz Damian , Steciuk Jaroslaw , Zugaj Dorota , Mielecki Damian , Sarnowski Tomasz J. , Grzesiuk Elżbieta
Published: March 2020

The family of AlkB homolog (ALKBH) proteins, the homologs ofEscherichia coliAlkB 2‐oxoglutarate (2OG), and Fe(II)‐dependent dioxygenase are involved in a number of important regulatory processes in eukaryotic cells including repair of alkylation lesions in DNA, RNA, and nucleoprotein complexes. There are nine human and thirteenArabidopsis thalianaALKBH proteins described, which exhibit diversified functions. Among them, human ALKBH5 and FaT mass and Obesity‐associated (FTO) protein and Arabidopsis ALKBH9B and ALKBH10B have been recognized as N6methyladenine (N6meA) demethylases, the most abundant posttranscriptional modification in mRNA. The FTO protein is reported to be associated with obesity and type 2 diabetes, and involved in multiple other processes, while ALKBH5 is induced by hypoxia. Arabidopsis ALKBH9B is an N6meA demethylase influencing plant susceptibility to viral infections via m6A/A ratio control in viral RNA. ALKBH10B has been discovered to be a functional Arabidopsis homolog of FTO; thus, it is also an RNA N6meA demethylase involved in plant flowering and several other regulatory processes including control of metabolism. High‐throughput mass spectrometry showed multiple sites of human ALKBH phosphorylation. In the case of FTO, the type of modified residue decides about the further processing of the protein. This modification may result in subsequent protein ubiquitination and proteolysis, or in the blocking of these processes. However, the impact of phosphorylation on the other ALKBH function and their downstream pathways remains nearly unexplored in both human and Arabidopsis. Therefore, the investigation of evolutionarily conserved functions of ALKBH proteins and their regulatory impact on important cellular processes is clearly called for.
Comparing therapy outcomes of patients before and after enrolling in an anticoagulation self‐testing program
Authors: Romano Teresa , Rein Lisa , Celebre Gregory , Hardman Jennifer
Published: March 2020

Purpose

Patients managed by the Froedtert & the Medical College of Wisconsin (F&MCW) Anticoagulation Clinics (ACC) have three monitoring options: face‐to‐face management, telephone management, or self‐testing management with limited clinician interaction only when International Normalized Ratios (INRs) are out of range or when clinically appropriate. To investigate if F&MCW ACC's current method of less frequent interaction for self‐testing is safe and effective, the purpose of this study was to determine if patients taking warfarin who were previously managed either face‐to‐face or via telephone call in the F&MCW ACC can be as effectively managed while self‐testing at home.

Methods

This pre‐post study analyzed data from face‐to‐face or telephone call anticoagulation management 6 months before and after each patient's self‐testing teach‐visit date. The primary outcome was the patients' time in therapeutic range (TTR) for INR values before and after enrolling in the self‐testing program. Secondary outcomes were the number of major bleeding and thromboembolic events and the number of INRs greater than 5.0 before and after transitioning to INR self‐testing. Patients served as their own control group for all outcomes of this study.

Results

The mean (standard deviation [SD]) TTR for subjects 6 months before and after transitioning to self‐testing was 69.9% (20.9) and 73.2% (18.0), respectively, demonstrating a statistically significant increase in TTR of 3.3% (25.4) with self‐testing (P = .047). Thirty‐six critical values occurred in the 6 months before self‐testing and 24 occurred in the 6 months after transitioning to self‐testing (P = .23). Additionally, four major bleeding and thromboembolic events occurred in four different patients in the 6 months after transitioning to self‐testing (P = .13).

Conclusions

F&MCW ACC's model for self‐testing management of every 2‐week self‐tests and limited clinician interaction demonstrates statistically significant improvements in TTR after patients transitioned to self‐testing. There was no statistically significant increase in adverse events following this transition.
Green synthesis of caffeine based on methylating reagent dimethyl carbonate and environmental friendly separating method
Authors: Yang Shu‐Zhen , Dong Zhi‐Qiang , Yin Cheng‐Cheng , Yue Hui‐Juan , Gao Wei‐Wei , Yang Feng‐Ke
Published: March 2020

In this paper, a green process for the synthesis and separation of caffeine was reported. Theophylline sodium is used as the raw material, diazabicyclo[5.4.0]undec‐7‐ene as the catalyst, and Turkey red oil as the solvent, particularly, dimethyl carbonate was adopted in place of high toxic dimethyl sulfate to form a mixture of caffeine and by‐product sodium bicarbonate. After converting sodium bicarbonate to sodium carbonate, the solubility difference between caffeine and sodium carbonate at 40°C was for the first time utilized to achieve the purpose of separating caffeine with an excellent yield of 98.4% and a purity of greater than 99.0%. Furthermore, both the reaction mother liquor and separation mother liquor can be recycled and reused during the reaction and separation processes, respectively, with little caffeine loss. No industrial waste was discharged in the process of the improved synthesis and separation, which is therefore environmental friendly.
Introduction to the Special Issue: Network Analysis of Traumatic Stress
Authors: Frewen Paul , O'Donnell Meaghan , D'Andrea Wendy
Published: March 2020

Network analysis has emerged as a promising new statistical methodology for traumatic stress studies. The present special issue of the Journal of Traumatic Stress amalgamates the reports of 10 studies that employed network analysis to further the field's understanding of traumatic stress. The current issue includes reports of network analyses that sought to better understand the impact of different kinds of traumatic events, including childhood and gender‐based trauma exposure, on PTSD symptomatology as defined under the DSM‐5 and ICD‐11, and examined the relation between PTSD symptoms and trauma‐related dissociative experiences as well as the impact of psychological treatment on trauma recovery. A variety of research designs from a diverse group of international samples were employed, including concurrent, longitudinal, experience‐sampling, and treatment outcome studies. Finally, a commentary on the articles included in this special issue was provided by Dr. Carl Weems.
Ein Gerät für jeden Laborplatz
Authors: Wejner Manuel , Wilke Timm
Published: March 2020

Messwerte im Unterricht quantitativ, präzise und kostengünstig zu erfassen, ist gar nicht so einfach – Messgeräte sind teuer und daher wenig vorhanden oder erfordern längere Einarbeitungszeit. Eine Alternative für Schule, Schülerlabor und Hochschulpraktikum ist eine digitale Messstation aus Low‐Cost‐Bauteilen und Miniatursensoren.
Chemie in der Sprache: Gierige Atome und gesellige Prozesse
Authors: Romstadt Jonas Konstantin , Martens Jürgen
Published: March 2020

In journalistischen und auch wissenschaftlichen Texten mit chemischem Inhalt ist zuweilen die Redewendung „die Chemie stimmt“ zu lesen. Sie unterscheidet sich von anderen plakativen Aussagen und Werbebotschaften, in denen die Chemie negativ erscheint. Seit wann „stimmt“ also „die Chemie“ und: Was passiert eigentlich, wenn dies nicht mehr der Fall ist? Hinweise geben Zeitungen und literarische Werke.
Wettbewerb: Präzision schlägt Tempo
Authors: Bulmahn Maren
Published: March 2020

Studierende lassen Modellfahrzeuge gegeneinander antreten. Die letztjährigen Sieger starteten ihr Gefährt mit einer elektrochemischen Reaktion und stoppten über eine Kristallisation.
Mal was Elementares: Kreuzworträtsel zum April
Authors: Bracher Franz
Published: March 2020

Nicht für die Credit Points, sondern fürs Leben lernen wir – und auch bei diesem Rätsel hilft chemisches Wissen weiter. Wer spicken will (muss), findet die Auflösung auf Seite 71.
Analysentechnik: Vom lernenden Sensor bis zur Spektrenvorhersage
Authors: Ehrensberger Christian
Published: March 2020

Kalibrieren schaffen Analysengeräte heute ohne menschliches Zutun. Bildgebende Systeme sortieren schlechte Produkte aus oder beurteilen ganze Chargen. Durch Abgleich mit Spektrenbibliotheken lassen sich Störsubstanzen schnell identifizieren, und für unbekannte Substanzen sagen Computermodelle das Infrarotspektrum vorher.
Fertig, los – Startschuss für neue CheMento‐Runde gefallen
Authors: Gajda Alina
Published: March 2020

Das Mentoring‐Programm der GDCh lebt von Engagement und Zielen; im Januar startete das Programm bereits in die vierte Runde mit 30 jungen Nachwuchschemikern.
Zukunftsthemen, Forschungsdaten, Internationalisierung
Authors: Karger Gerhard
Published: March 2020

Zur zweitägigen Beratung mit dem GDCh‐Präsidenten kamen 27 Repräsentanten von GDCh‐Fachgruppen und ‐Arbeitsgemeinschaften, ein Vertreter des JungChemikerForums sowie Mitarbeiter der GDCh‐Geschäftsstelle Ende Oktober 2019 im Exerzitienhaus Himmelspforten in Würzburg zusammen.
An effective evidence‐based cleaning method for the safe reuse of intermittent urinary catheters: In vitro testing
Authors: Wilks Sandra A. , Morris Nicola S. , Thompson Richard , Prieto Jacqui A. , Macaulay Margaret , Moore Katherine N. , Keevil C. William , Fader Mandy
Published: March 2020

Aims

To determine a safe bactericidal cleaning method that does not damage urethral catheters used for intermittent catheterization. In some countries, single‐use catheters are the norm; in others, the reuse of catheters is common depending on health insurance, personal preference, or individual concerns about the environment. However, no recent study of cleaning methods has been published to provide evidence for the safe reuse of catheters.

Methods

Using advanced microbiological methods, a laboratory study of eight cleaning methods was conducted. Sections of uncoated polyvinylchloride (PVC) catheters were exposed to bacterial uropathogens in physiologically correct artificial urine media then tested with a range of heat, chemical, and mechanical cleaning methods. Analysis of culturable and viable but nonculturable (VBNC) bacteria was done and direct microscopy was used. Descriptive statistics were used to compare values.

Results

Heat treatments, although effective, resulted in catheter surface breakdown and damage. Ultrasonic cleaning and vinegar showed evidence of VBNC populations indicating the methods were bacteriostatic. Detergent and water wash followed by immersion in a commercially available 0.6% sodium hypochlorite solution and 16.5% sodium chloride (diluted Milton) gave consistent bactericidal results and no visible catheter damage.

Conclusions

Combined mechanical and chemical treatment of a detergent and water wash followed by immersion in diluted Milton (the “Milton Method”) provided consistent and effective cleaning of uncoated PVC catheters, showing bactericidal action for all uropathogens tested after repeated exposure. If found safe in clinical testing, this method could increase the reuse of catheters, reduce plastic waste in the environment, reduce cost, and increase patient choice.
N,O‐Nucleoside Analogues: Metabolic and Apoptotic Activity
Authors: Marraffa Andrea , Presenti Piero , Macchi Beatrice , Marino‐Merlo Francesca , Mella Mariella , Quadrelli Paolo
Published: March 2020

Two new families of N,O‐nucleoside analogues containing the anthracene moiety introduced through the nitrosocarbonyl ene reaction with allylic alcohols were prepared. The core structure is an isoxazolidine heterocycle that introduces either atom either a phenyl ring or dimethyl moiety at the C3 carbon. Different heterobases were inserted at the position 5 of the heterocyclic ring. One of the synthesized compounds demonstrated a good capacity to induce cell death and an appreciable nuclear fragmentation was evidenced in treated cells.
Preventing radicalism in educational institutions: Pakistan a case in point
Authors: Ali Yousaf , Ahmad Abrar , Shah Zainab A. , Awan Muhammad A.
Published: March 2020

With the recent drastic shifts in societies, thinking styles, and most importantly, the degree of online‐and‐offline exposure, it is easy for the young and developing mind to fall prey to radical or extremist ideas. Radical organizations direct their recruiting efforts toward those who have yet to reach adolescence and are incapable of forming well‐informed and educated decisions. Since it is in human nature to target the weak and the vulnerable, these organizations look for dissatisfied, isolated and friendless young people. They are especially allured when these organizations promise to get them all they lack. As there have been incidents recently reported on young students' involvement in terror activities, the study proposes alternatives to prevent them from falling prey to radical thoughts. The proposed alternatives are judged through TOPSIS (Technique of Order Preference Similarity to the Ideal Solution) and the ideal alternative is singled out after mathematical calculation. Out of the five proposed alternatives, the study, through TOPSIS analysis, proposes that parents may be trained to handle their children in order to keep them from radical thoughts. In addition to the ideal alternative, the study also suggests that the government take preventive measures to curb the evil of radicalism.
Initial in vivo testing of a multitarget kinase inhibitor, regorafenib, by the Pediatric Preclinical Testing Consortium
Authors: Harrison Douglas J. , Gill Jonathan D. , Roth Michael E. , Zhang Wendong , Teicher Beverly , Erickson Stephen , Gatto Greg , Kurmasheva Raushan T. , Houghton Peter J. , Smith Malcolm A. , Kolb Edward Anders , Gorlick Richard
Published: March 2020

Background

Regorafenib is a small molecule multikinase inhibitor that inhibits multiple kinases including BRAF, KIT, PDGFRB, RAF, RET, and VEGFR1‐3.

Procedures

The in vivo anticancer effects of regorafenib were assessed in a panel of six osteosarcoma models, three rhabdomyosarcoma models, and one Ewing sarcoma model.

Results

Regorafenib induced modest inhibition of tumor growth in the models evaluated.

Conclusion

The overall pattern of response to regorafenib appears similar to that of the kinase inhibitor sorafenib, with pronounced slowing of tumor growth in some models, limited to the period of agent administration, being the primary treatment effect.
Design, synthesis and evaluation of E2‐25K derived stapled peptides
Authors: Watson Morag E. , Scott Daniel , Jamieson Craig , Layfield Robert , Mason Andrew M.
Published: March 2020

Stabilised peptides are now established as potential drug candidates to probe previously intractable molecular targets, such as protein‐protein interactions. Herein, we report the design and synthesis of eight short helical peptide analogues of the ubiquitin conjugating enzyme, E2‐25K, as potential antagonists of the interaction between E2‐25K and the Alzheimer's Disease (AD) associated ubiquitin mutant Ubb + 1. Biochemical evaluation revealed four putative antagonists of the Ubb + 1/E2‐25K interaction that reduced incorporation of Ubb + 1 into polyubiquitin chains in vitro, validating the potential of this approach as a therapeutic strategy.
Miniaturized and Thermal‐Based Measurement System to Measure Moisture in Textile Materials
Authors: Schönfisch David , Göddel Michael , Blinn Jörg , Heyde Christian , Schlarb Heiko , Deferme Wim , Picard Antoni
Published: March 2020

Moisture in textile materials worn close to the skin greatly influences our daily comfort. The measurement of moisture in textile materials is therefore of great interest, for example, to determine the amount of perspiration in clothing or car seats, the wound fluid in dressings, or even the urine in diapers or bed linen. All these applications require a robust moisture measurement method, which is harmless to humans and measures in thin layers. One method ideally suited to fit these requirements is the transient‐heat moisture sensing (THMS) method. Herein, a miniaturized and evolved adaption of the THMS method is shown. The measurement system presented herein is optimized for low energy consumption and portability. The working principle of this measuring system is demonstrated by conducting a simple test to investigate the transplanar wicking of eight fundamentally different but garment‐typical textiles. The THMS method and its ability to measure in thin layers that is ideally suited to measure moisture in thin layers are shown. Finally, it lays a foundation to enable a multitude of future applications, wherever moisture (e.g., sweat) is to be measured with high accuracy and with a wearable system close to the human skin.
Isotopic fractionation during acid digestion of calcite: A combined ab initio quantum chemical simulation and experimental study
Authors: Pramanik Chirantan , Chatterjee Swastika , Fosu Benjamin R. , Ghosh Prosenjit
Published: March 2020

Rationale

Carbonate clumped isotope analysis involves the reaction of carbonate minerals with phosphoric acid to release CO2 for measurement in a gas‐source isotope ratio mass spectrometer. Although the clumped isotope proxy is based on the temperature dependence of 13C–18O bonding preference in the mineral lattice, which is captured in the product CO2, there is limited information on the phosphoric acid reaction mechanism and the magnitude of clumped isotopic fractionation (mass 63 in CO32− to mass 47 in CO2) during the acid digestion.

Methods

We studied the reaction mechanism for the phosphoric acid digestion of calcite using first‐principles density functional theory. We identified the transition state structures for each reaction involving different isotopologues and used the corresponding vibrational frequencies in reduced partition function theory to estimate the Δ47 acid fractionation. Experimental Δ47 data were acquired by processing the sample CO2 gas through the dual‐inlet peripheral of a ThermoFinnigan MAT253 isotope ratio mass spectrometer.

Results

We showed that the acid digestion reaction, which results in the formation of CO2 enriched with 13C–18O bonds, began with the protonation of calcium carbonate in the presence of water. Our simulations yielded a relationship between the Δ47 acid fractionation and reaction temperature as Δ47 = −0.30175 + 0.57700 × (105/T2) – 0.10791 × (105/T2)2, with T varying between 298.15 and 383.15 K.

Conclusions

We propose a reaction mechanism that shows a higher slope (Δ47 acid fractionation vs. 1/T2 curve) for the phosphoric acid digestion of calcite than in previous studies. The theoretical estimates from the present and earlier studies encapsulate experimental observations from both “sealed vessel” and “common acid bath” acid digestion methods.
Cauliflower‐Like Hierarchical Porous Nickel/Nickel Ferrite/Carbon Composite as Superior Bifunctional Catalyst for Lithium‐Air Battery
Authors: Athika Mattath , Devi Vaithiyanathan Sankar , Elumalai Perumal
Published: March 2020

Rational design of cost‐effective oxygen electrode catalysts for metal‐air batteries is indispensable for developing next‐generation energy storage devices especially to use in electric vehicles. In this work, non‐precious Nickel/Nickel Ferrite on carbon matrix (NNFOC) nanocomposite as bifunctional air‐breathing electrode for rechargeable Li‐air battery is proposed. The NNFOC composite on rotating ring disc electrode (RRDE) exhibited good oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities. The synergistic contribution from Ni, nickel ferrite and porous carbon network that resulted more reaction sites, high conductivity and fast diffusion pathways, lead to enhanced ORR and OER activities. The CR‐2032 coin‐type and conventional split cell Li‐air battery were fabricated using the NNFOC composite as air‐breathing oxygen electrode and lithium metal as anode. The open‐circuit voltage of the coin cell was invariant for more than 5 days, while the split cell exhibited high discharge capacity of 3820 mAh g‐1 at a current density of 50 mA g‐1. The charged split cell could power a commercial 2.8 V LED bulb for more than 5 h continuously.
Enhanced Oxygen Reduction Reaction by Pd‐Pt Alloy Catalyst with Stabilized Platinum Skin
Authors: Swami Anita , Patil Indrajit , Lokanathan Moorthi , Ingavale Sagar , Kakade Bhalchandra
Published: March 2020

Reducing the consumption of precious Platinum (Pt) metal by alloying with other transition metals or searching a new low cost, Pt‐free catalyst with the activity and durability higher than the state‐of‐the‐art Pt/C catalyst are the two possible approaches to accelerate the practical application of low temperature fuel cells. Herein we investigate the oxygen reduction reaction (ORR) electrocatalytic activity (1023 μA cm−2.Pt; 5 times higher than commercial Pt/C) and the corrosion stability of novel “Pt skin@PdPt” nanostructures in acidic media. An interesting trend of increment in the ORR activity with durability cycles has been found indicating a systematic surface rearrangement in “Pt skin@PdPt”. A systematic enhancement in the ORR activity from an initial value of 1023 μA cm−2.Pt to 1448 μA cm−2.Pt after 30,000 durability cycles has been observed indicating stable nature of low Pt content Pt skin@PdPt electrocatalyst. More than seven times (1448 μA cm−2.Pt) higher activity against the state‐of‐the‐art Pt/C catalyst has been seen with an electrochemical surface area (ECSA) of ∼97 m2 g−1.Pt, even after 30,000 potential cycles.
Improved Average Figure‐of‐Merit of High‐Efficiency Nonfullerene Solar Cells via Minor Combinatory Side Chain Approach
Authors: Yuan Dong , Pan Feilong , Zhang Lianjie , Jiang Haiying , Chen Mingjun , Tang Wei , Qin Guoming , Cao Yong , Chen Junwu
Published: March 2020

The cost‐effectiveness of polymer solar cells is a very important concern for future applications. In this work, a new combinatory side chain integrating siloxane terminal and alkoxy group is developed, and three polymers, PQSi05, PQSi10, and PQSi25, with 5%, 10%, and 25% contents of the siloxane‐terminated alkoxy side chain, respectively, are successfully synthesized. As the content of the combinatory side chain increases, the surface energy of the corresponding polymer film decreases, showing tunable miscibility in blend films with nonfullerene acceptor IT‐4F. A maximum power conversion efficiency (PCE) of 13.56% is achieved in the PQSi05:IT‐4F‐based device. The minor (5%) combinatory side chain approach retains a low synthetic complexity (SC) of 16.58% for PQSi05. Due to the improved device performance, a low figure‐of‐merit (FOM) of 1.22 is obtained for the PQSi05:IT‐4F blend. Furthermore, the contribution of the IT‐4F acceptor is considered for a comprehensive analysis, yielding an average SC (ASC) of 39.31% and an average FOM (AFOM) of 2.90. After statistical analyses and calculations, the PQSi05:IT‐4F is the best cost‐effective active layer to date. It is revealed that the introduction of the minor combinatory side chain is a promising strategy to develop high‐performing and cost‐effective polymer donors.
Production and Anisotropic Tensile Properties of Stainless Steel Wire Mesh/ZA8 Alloy Composites Produced by Squeeze Casting
Authors: Yao Bibo , Zhou Zhaoyao , Chen Zengtao , Wang Junwen
Published: March 2020

Novel stainless steel/zinc alloy composites are produced by infiltrating ZA8 zinc alloy into rolled 304 stainless steel wire mesh preforms via squeeze casting. Microstructural characteristics of the composite are observed, and the uniaxial tensile properties at different temperatures are investigated. The tensile properties of the composites of sintered preforms are compared with those of the composites of unsintered preforms. The results indicate that the microstructures and tensile behavior of the composites exhibit anisotropy. The tensile strength of the composite in the longitudinal direction is higher than that in the radial direction and increases with increasing wire fraction. The tensile strength and elongation at the maximum stress of the composite are lower than those of the unreinforced ZA8 alloy tested at room temperature. At an elevated temperature, the tensile strength of the alloy is improved but ductility decreases after adding wire mesh with wire fraction more than a certain value. The strength and elastic modulus of the alloy and composites sharply decrease with an increase in testing temperatures. The tensile strength of the composite decreases after sintering preforms. The fracture surface of the composite shows anisotropy in different directions and different morphologies at different temperatures.
Effect of rotor–tower interaction, tilt angle, and yaw misalignment on the aeroelasticity of a large horizontal axis wind turbine with composite blades
Authors: Santo Gilberto , Peeters Mathijs , Van Paepegem Wim , Degroote Joris
Published: March 2020

This paper presents a detailed analysis of the rotor–tower interaction and the effects of the rotor's tilt angle and yaw misalignment on a large horizontal axis wind turbine. A high‐fidelity aeroelastic model is employed, coupling computational fluid dynamics (CFD) and structural mechanics (CSM). The wind velocity stratification induced by the atmospheric boundary layer (ABL) is modeled. On the CSM side, the complex composite structure of each blade is accurately modeled using shell elements. The rotor–tower interaction is analyzed by comparing results of a rotor‐only simulation and a full‐machine simulation, observing a sudden drop in loads, deformations, and power production of each blade, when passing in front of the tower. Subsequently, a tilt angle is introduced on the rotor, and its effect on blade displacements, loads, and performance is studied, representing a novelty with respect to the available literature. The tilt angle leads to a different contribution of gravity to the blade deformations, sensibly affecting the stresses in the composite material. Lastly, a yaw misalignment is introduced with respect to the incoming wind, and the resulting changes in the blade solicitations are analyzed. In particular, a reduction of the blade axial displacement amplitude during each revolution is observed.
Continuous authentication using biometrics: An advanced review
Authors: Dahia Gabriel , Jesus Leone , Pamplona Segundo Maurício
Published: March 2020

The shortcomings of conventional access control systems for high‐security environments have led to the concert of continuous authentication. Contrary to traditional verification, in which users are authenticated only once at the start of their session, continuous authentication systems regularly check users' identities to prevent hijackings. The challenges in this area involve balancing the security of protected assets by quickly detecting intruders with the system usability for genuine users. Biometric recognition plays a major role within this context, as it is the main way to assure that users are who they claim to be. A comparative analysis of the latest works revealed different aspects of this problem. First, some biometrics traits among those applied for continuous authentication are more suitable for this task than others. Second, systems combining multiple traits have advantages over those relying on a single one. Finally, many works fail to report proper evaluation metrics. With this in mind, we were able to identify new opportunities for researchers in the field. We highlight the potential for mining new datasets on the internet, which would benefit validation and benchmarking, and how recent deep learning techniques could address some of the open challenges in the area.

This article is categorized under:

Technologies > Prediction

Technologies > Machine Learning

Application Areas > Science and Technology
Two-loop conformal invariance for Yang-Baxter deformed strings
Authors: Borsato Riccardo , Wulff Linus
Published: March 2020

Abstract

The so-called homogeneous Yang-Baxter (YB) deformations can be considered a non-abelian generalization of T-duality-shift-T-duality (TsT) transformations. TsT transformations are known to preserve conformal symmetry to all orders in α′. Here we argue that (unimodular) YB deformations of a bosonic string also preserve conformal symmetry, at least to two-loop order. We do this by showing that, starting from a background with no NSNS-flux, the deformed background solves the α′-corrected supergravity equations to second order in the deformation parameter. At the same time we determine the required α′-corrections of the deformed background, which take a relatively simple form. In examples that can be constructed using, possibly non-commuting sequences of, TsT transformations we show how to obtain the first α′-correction to all orders in the deformation parameter by making use of the α′-corrected T-duality rules. We demonstrate this on the specific example of YB deformations of a Bianchi type II background.
New R-matrices with non-additive spectral parameters and integrable models of strongly correlated fermions
Authors: Zhang Yao-Zhong , Werry Jason L.
Published: March 2020

Abstract

We present a general formula for constructing R-matrices with non-additive spectral parameters associated with a type-I quantum superalgebra. The spectral parameters originate from two one-parameter families of inequivalent finite-dimensional irreducible representations of the quantum superalgebra upon which the R-matrix acts. Applying to the quantum superalgebra Uq(gl(2|1)), we obtain the explicit expression for the Uq(gl(2|1))− invariant R-matrix which is of non-difference form in spectral parameters. Using this R­ matrix we derive a new two-parameter integrable model of strongly correlated electrons with pure imaginary pair hopping terms.
The quest for purely virtual quanta: fakeons versus Feynman-Wheeler particles
Authors: Anselmi Damiano
Published: March 2020

Abstract

The search for purely virtual quanta has attracted interest in the past. We consider various proposals and compare them to the concept of fake particle, or “fakeon”. In particular, the Feynman-Wheeler propagator, which amounts to using the Cauchy principal value inside Feynman diagrams, violates renormalizability, unitarity and stability, due to the coexistence of the prescriptions ±iE. We contrast the Feynman, fakeon and Feynman- Wheeler prescriptions in ordinary as well as cut diagrams. The fakeon does not have the problems of the Feynman-Wheeler propagator and emerges as the correct concept of purely virtual quantum. It allows us to make sense of quantum gravity at the fundamental level, and places it on an equal footing with the standard model. The resulting theory of quantum gravity is perturbative up to an incredibly high energy.
Effects of heat treatment on thermal properties of European beech wood
Authors: Czajkowski Łukasz , Olek Wiesław , Weres Jerzy
Published: March 2020

Beech wood, due to its properties, is one of the most versatile and successfully used construction materials. The wood properties could even be improved, and among different wood modification processes, the thermal modification approach is usually considered as an environment-friendly technology based only on the heat and water application during wood treatment. Changes in material properties resulting from the thermal treatment of wood increase applicability of this material, but on the other hand, detailed knowledge of the modified properties is definitely necessary for the proper application of such materials to construction engineering. Unfortunately, credible data on thermal characteristics of thermally modified wood are usually provided in a very limited way, and there is no information on specific heat in particular. An original calorimetric method was used to determine the specific heat of untreated and thermally modified European beech wood (Fagus sylvaticaL.). The inverse modeling was implemented to estimate the anisotropic thermal conductivity, and significant differences were found for the radial and tangential directions. The thermal modification highly influenced the increase in the thermal conductivity in the longitudinal direction. The validation procedure showed credibility of the applied methods, and it is clear that modeling of heat transfer in thermally modified wood leads to erroneous results when using thermal properties determined merely for untreated wood.
Risk factors for non-closure of an intended temporary defunctioning stoma after emergency resection of left-sided obstructive colon cancer
Authors:   on behalf of the Dutch Snapshot Research Group, van Ommeren–Olijve S. J. , Burbach J. P. M. , Furnée E. J. B.
Published: March 2020

Purpose

A substantial part (21–35%) of defunctioning stomas created during resection for colorectal cancer will never be reversed. Known risk factors for non-closure are age, peri- or postoperative complications, comorbidity, and tumor stage. However, studies performed to identify these risk factors mostly focus on rectal cancer and include both preoperative and postoperative factors. This study aims to identify preoperative risk factors for non-reversal of intended temporary stomas created during acute resection of left-sided obstructive colon cancer (LSOCC) with primary anastomosis.

Methods

All patients who underwent emergency resection for LSOCC with primary anastomosis and a defunctioning stoma between 2009 and 2016 were selected from the Dutch ColoRectal Audit, and additional data were collected in the local centers. Multivariable analysis was performed to identify independent preoperative factors for non-closure of the stoma.

Results

A total of 155 patients underwent acute resection for LSOCC with primary anastomosis and a defunctioning stoma. Of these, 51 patients (32.9%) did not have their stoma reversed after a median of 53 (range 7–104) months of follow-up. In multivariable analysis, hemoglobin < 7.5 mmol/L (odds ratio (OR) 4.79, 95% confidence interval (95% CI) 1.60–14.38, p = 0.005), estimated glomerular filtration rate (eGFR) ≤ 45 mL/min/1.73 m2 (OR 4.64, 95% CI 1.41–15.10, p = 0.011), and metastatic disease (OR 6.12, 95% CI 2.35–15.94, p < 0.001) revealed to be independent predictors of non-closure.

Conclusions

Anemia, impaired renal function, and metastatic disease at presentation were found to be independent predictors for non-reversal of intended temporary stomas in patients who underwent acute resection for LSOCC. In patients who have an increased risk of non-reversal, the surgeon should consider a Hartmann’s procedure.
The Steel Industry in the European Union on the Crossroad to Carbon Lean Production—Status, Initiatives and Challenges
Authors: Draxler Monika , Schenk Johannes , Bürgler Thomas , Sormann Axel
Published: March 2020

The EU commission has committed to fulfil the targets of greenhouse gas (GHG) emission reduction in 2050 by 80% in comparison to the level of 1990. The fulfilment of the EU’s climate policies brings new challenges for the iron and steel industry. The European steel industry is forced to develop strategies for the transition of their technology to a carbon lean production and to keep the competitiveness in the world market. The steel companies in EU27 are taking the challenge to secure the steel production in Europe and have launched innovation projects for CO2mitigation with the focus on the technological pathways Carbon Direct Avoidance (CDA) and Smart Carbon Usage (SCU), which are, beside Circular economy, defined as important pillars for CO2abatement in European steel industry. The transformation of the steel industry must go hand in hand with a decarbonisation of the energy supply and other industries within EU27.
From St. John’s wort to tomato and from Rhodiola to cranberry
Authors: Weixlbaumer Verena , Draxler Lukas , Zeitlinger Markus , Prantl Benedikt
Published: March 2020

Background

This study evaluated the definition, the prevalence of use and the governmental regulations of phytotherapy and four examples of herbal medicine are discussed in more detail.

Results

This research group evaluated 4 topics: St. John’s wort for treating (mild to moderate) depression, tomato extract as a platelet inhibitor, Rhodiola against stress-related fatigue and cranberries for the treatment of urinary tract infections.

Conclusion

The findings were diverse and must be individually taken into account. Evidence for efficacy varies within and between the four examples. An explanation for the lack of reproducibility of findings from preclinical and clinical experiments might be the insufficient standardization of herbal medicines. There is no scientific reason why phytotherapy should not be investigated with the same rigor as conventional drugs to establish the efficacy and potential risks. Meanwhile, it is concluded that care is essential when using herbal medicine in the daily routine and informing patients about potential shortcomings and dangers of herbal medicines should be considered a duty of pharmacists and physicians.
Permutation Matrices, Their Discrete Derivatives and Extremal Properties
Authors: Brualdi Richard A. , Dahl Geir
Published: March 2020

For a permutation π, and the corresponding permutation matrix, we introduce the notion of discrete derivative, obtained by taking differences of successive entries in π. We characterize the possible derivatives of permutations, and consider questions for permutations with certain properties satisfied by the derivative. For instance, we consider permutations with distinct derivatives, and the relationship to so-called Costas arrays.
Abnormality of multimodal evoked potentials in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)
Authors: Dziadkowiak Edyta , Ejma Maria , Wieczorek Malgorzata , Pec Pawel , Slotwiński Krzysztof , Budrewicz Slawomir , Zimny Anna , Koszewicz Magdalena
Published: March 2020

Introduction

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune disease of the peripheral nervous system, sometimes including the central nervous system. The aim of the study was the assessment of the prevalence of central sensory impairment and its reliance on peripheral nerve damage in patients with CIDP.

Material and methods

Multimodal (visual—VEP, brainstem auditory—BAEP, somatosensory—SEP) evoked potentials (EPs) were studied in 24 patients diagnosed with CIDP. The results were compared with neurographic parameters of sensory responses. The control group consisted of 35 healthy volunteers selected with respect to age and sex.

Results

Mean latency of most components of EP were considerably prolonged in patients compared with the control group. There were no correlations between the P100 VEP latency and the peripheral sensory parameters. Statistically significant negative correlations were obtained between BAEP and SEP responses and the amplitude and sensory conduction velocity of peripheral nerves. The inter-latencies were also longer.

Conclusions

The authors indicated to the possibility of central sensory involvement in patients with CIDP, especially based on the prolonged inter-latency of BAEPs with simultaneously confirmed root affection. The severity of central damage correlates with the degree of peripheral nerve impairment.
Association between food patterns and difficulties in falling asleep among adolescents in Norway — a descriptive Young-Hunt3 study
Authors: André Beate , Canhão Helena , Espnes Geir A. , Rodrigues Ana Maria Ferreira , Gregorio Maria Joao , Nguyen Camilla , Sousa Rute , Grønning Kjersti
Published: March 2020

Aim

Adolescents’ sleep duration has decreased over the past century; this is mainly caused by problems with falling asleep. Short sleep duration, poor sleep quality, and later bedtimes, in addition to difficulties in falling asleep, are further associated with adolescents’ increased food intake, poor diet quality, and excess body weight. Obesity has become a major health worldwide problem, with increasing prevalence among several age groups. In addition, higher body mass index is one of the most consistently reported correlates of short sleep duration. The aim of this study was to study if short sleep duration, connected with problems falling asleep, is associated with obesity and weight gain among Norwegian adolescents.

Subject and methods

This is a cross-sectional study using data from the Young-HUNT3 cohort study, which comprises the adolescent part of HUNT3. Young-HUNT3 includes data on 8217 participants aged 13 to 20 years old. Cluster analysis were used to categorize patterns of similarities in food consumption. Bivariate analyses were conducted to explore associations between difficulties in falling asleep and unhealthy food patterns.

Results

The analyses found statistically significant differences (< 0.001) between adolescents having an unhealthy food pattern, higher BMIs, and more difficulties with falling asleep than adolescents with a healthy food pattern.

Conclusion

This study shows that an unhealthy food pattern is associated with shorter sleep duration among Norwegian adolescents. Health promotion educational interventions focusing on disseminating knowledge to parents and adolescents about unhealthy food intake and other risk factors related to insufficient sleep ought to be developed.