bluuebunny/crossref_metadata_2025 huggingface dataset:
Central nervous system involvement by severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2)
Authors: Paniz‐Mondolfi Alberto , Bryce Clare , Grimes Zachary , Gordon Ronald E. , Reidy Jason , Lednicky John , Sordillo Emilia Mia , Fowkes Mary
Published: April 2020

Neurologic sequelae can be devastating complications of respiratory viral infections. We report the presence of virus in neural and capillary endothelial cells in frontal lobe tissue obtained at postmortem examination from a patient infected with severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2). Our observations of virus in neural tissue, in conjunction with clinical correlates of worsening neurologic symptoms, pave the way to a closer understanding of the pathogenic mechanisms underlying central nervous system involvement by SARS‐CoV‐2.
How institutional pressures and managerial incentives elicit carbon transparency in global supply chains
Authors: Villena Verónica H. , Dhanorkar Suvrat
Published: April 2020

Carbon transparency, once a niche practice, is increasingly becoming institutionalized. Firms are now required to report not only their operations' carbon emissions but also their suppliers'. This research explores the institutional pressures emanating from buyers and industry peers driving supplier firms to disclose high‐quality carbon emission publicly—our concept of carbon transparency. Many firms are increasingly adopting incentives to engage their employees in corporate climate change programs. Thus, we study the impact of three institutional pressures—coercive, mimetic, and normative—and examine when these pressures are more (or less) effective for driving supplier carbon transparency depending on the presence of climate change incentives. We used Carbon Disclosure Project's supply chain program (CDP‐SCP) as our research context. To gain deeper insight into the CDP‐SCP as well as the drivers and challenges of suppliers' carbon transparency, we conducted interviews with three CDP officials, three CDP‐SCP members (i.e., buyers), and six CDP‐SCP participants (i.e., suppliers). To test our hypotheses, we used a unique dataset from CDP‐SCP and complemented it with four other archival datasets for a sample of 835 suppliers operating in 41 countries during the 2013–2015 period. The results show that suppliers without climate change incentives are more vulnerable to coercive and mimetic pressures, whereas suppliers with climate change incentives are more receptive to normative pressure in terms of how much carbon transparency they exhibit. Thus, our study proposes an extensive concept of supplier carbon transparency, provides a comprehensive analysis of its external/internal drivers, and reveals when institutional pressures are more/less effective in eliciting supplier carbon transparency. This research also provides strategies for how buyers, suppliers, and CDP can foster more carbon transparency in supply chains.
Carotid Ultrasound to Predict Fluid Responsiveness
Authors: Beier Lance , Davis Joshua , Esener Dasia , Grant Charles , Fields J. Matthew
Published: April 2020

Objectives

To perform a systematic review of the accuracy of carotid ultrasound measures in determining volume responsiveness in adults.

Methods

We conducted a systematic review of Ovid MEDLINE and Scopus from conception until January 1, 2019. Two independent reviewers used an iterative process to identify relevant articles and abstract information from them. The quality and risk of bias were assessed with the Quality Assessment of Diagnostic Accuracy Studies version 2 tool.

Results

We identified 17 relevant articles with 956 patients. The 2 most frequently cited carotid measures of fluid responsiveness were corrected flow time and peak velocity or change in peak velocity with respiration (ΔCDPV). Accordingly, the diagnostic characteristics of corrected flow time in these studies varied widely, with sensitivities from 60% to 73%, specificities from 82% to 92%, and areas under the receiver operating characteristic curves from 0.75 to 0.88. Optimal cutoff values for ΔCDPV ranged from 9.1% to 14%, with areas under the receiver operating characteristic curves from 0.81 to 0.91, sensitivities from 73% to 86%, and specificities from 78% to 86%. Other measures, such as carotid blood flow and carotid diameter, had limited data to support their use. Heterogeneity of the studies prohibited a meta‐analysis. Most studies had a moderate risk of bias and high applicability.

Conclusions

Preliminary research suggests that carotid ultrasound measures may be useful adjunct measures of fluid status; however, they should not be interpreted as absolute and should be placed in a clinical context. The most well‐defined and supported measure currently is ΔCDPV, with cutoffs from 9% to 14%. Corrected flow time shows promise, because of heterogeneity of how this value is measured, an optimal cutoff has not been established.
Supply chain finance: A three‐party decision model with suppliers' guarantees for retailers
Authors: Yan Bo , Luo Kun , Liu Li‐Feng , Chen Yan‐Ru , Yang Yi‐Fan
Published: April 2020

Under the premise that financing constraints frequently occur in the supply chain, this paper investigates the financing model of the supplier providing guarantee for the retailer under symmetric and asymmetric information. The optimal solutions of the retailer, the supplier, and the bank are studied by using the Stackelberg game. Results show that increasing the supplier's guarantee proportion can effectively improve the bank's reasonable margin rate and increase the supplier's profit. Under the condition of asymmetric information, the bank can increase the probability of credit loan in the supply chain by reducing the cost of spot check and setting up a reasonable fine limit.
General decay and blow up of solution for a nonlinear wave equation with a fractional boundary damping
Authors: Aounallah Radhouane , Boulaaras Salah , Zarai Abderrahmane , Cherif Bahri
Published: April 2020

The paper deals with the study of global existence of solutions and the general decay in a bounded domain for nonlinear wave equation with fractional derivative boundary condition by using the Lyaponov functional. Furthermore, the blow up of solutions with nonpositive initial energy combined with a positive initial energy is established.
A 45‐61 GHz monolithic microwave integrated circuit subharmonic mixer incorporating dual‐band power divider
Authors: Zhang Liang , Tong Xiaodong , Han Jiang‐an , Cheng Xu
Published: April 2020

In this article, a novel design and realization of wideband subharmonic mixer (SHM) operating over the 45‐61 GHz frequency band is presented, in which a dual‐band power divider (DBPD), an antiparallel diode pair (APDP), and a LC low‐pass filter are employed. Working in the two corresponding frequency bands, the DBPD not only imports the RF and the LO signals, but also provides impedance transformation between the APDP, RF, and LO ports. Due to the inherent ports isolation and matching characteristics of DBPD, a simplified and miniaturized configuration of SHM has been achieved. The monolithic microwave integrated circuit (MMIC) is implemented by a GaAs 0.15 μm pHMET process with a compact chip size of 1 × 0.95 mm2 including probe pads. The mixer exhibits 14.8 to 16.5 dB conversion loss with improved return losses at the RF, LO, and IF ports. The LO‐to‐RF, LO‐to‐IF, RF‐to‐IF, 2LO‐to‐RF, and 2LO‐to‐IF isolations are 16.5 to 34.5 dB, 35 to 41.5 dB, 30 to 40 dB, 32.5 to 39.5 dB, and 50 to 61.5 dB, respectively. To the author's best knowledge, the DBPD is used in MMIC SHM design for the first time.
Miniaturized broadband‐multiband planar antenna with a symmetric quarter‐circular ground plane for WLAN/WiMAX standards
Authors: El Yassini Abdessalam , Ibnyaich Saida , Chabaa Samira , Zeroual Abdelouhab
Published: April 2020

In this paper, a novel design of miniature and broadband‐multiband coplanar waveguide‐fed planar antenna with a symmetric quarter‐circular ground plane is suggested to realize multiband with better performance. The experimental results show that the suggested antenna has achieved two bandwidths (S11 < −10 dB): the lower band from 2.34 to 2.42 GHz centered around the resonant frequency of 2.38 GHz and the upper broadband from 3.16 to 6.57 GHz resonating at 3.5 and 5.38 GHz, respectively. The bandwidths cover the two required bands: WiMAX and WLAN at the frequencies 3.5/5.5 and 2.4/5.2/5.8 GHz, respectively. All these three resonant frequencies show better impedance matching with convenient gain and high radiation efficiency; moreover, the radiation patterns in the H‐plane and E‐plane are omnidirectional and bidirectional, respectively. The patch antenna prototype is constructed on a simple substrate named FR4 epoxy and having total dimensions of 0.23λ × 0.14λ × 0.012λ, as λ is the free‐space wavelength at the lower resonant frequency. In addition, the resulting multiband antenna is a highly compact size and having a good performance, which makes it appropriate for wireless systems in diverse applications.
Educational needs of patients with rheumatic and musculoskeletal diseases attending a large health facility in Austria
Authors: Hirsch Jameson K. , Toussaint Loren , Offenbächer Martin , Kohls Niko , Hanshans Christian , Vallejo Miguel , Rivera Javier , Sirois Fuschia , Untner Johannes , Hölzl Bertram , Gaisberger Martin , Ndosi Mwidimi
Published: April 2020

Introduction

Patient education is an important part of the management of rheumatic and musculoskeletal diseases. Given that patients with diverse diseases do not have the same needs, it is crucial to assess the educational requirements of targeted groups to provide tailored educational interventions. The aim of our study was to assess educational needs of a large cohort of patients with different rheumatic and musculoskeletal diseases attending a health facility in Austria.

Methods

We assessed educational needs, via an online survey of patients with fibromyalgia (FMS), rheumatoid arthritis (RA), and ankylosing spondylitis (AS) recruited from an Austrian health‐care facility, using the Austrian version of the Educational Needs Assessment Tool (OENAT).

Results

For our sample of 603 patients, AS (62%), RA (15%), and FMS (24%), there were no educational need differences for the domains of movements, disease process, and self‐help measures. Patients with FMS had less need for pain management education and greater need for education about feelings, than other disease groups. Patients with RA had a greater need for education related to treatments than other groups, and patients with AS had a greater need for treatment education than patients with FMS. Patients with AS reported greater need for support system education than other patient groups.

Conclusion

Educational needs vary by disease groups, suggesting that health‐care professionals should assess disease‐specific needs for education to provide optimal assistance in disease management for patients.
Achieving a high thermal conductivity for segregated BN/PLA composites via hydrogen bonding regulation through cellulose network
Authors: Shen Wanting , Wu Wei , Liu Chao , Wang Zhengyi , Huang Zhengqiang
Published: April 2020

Normally, the effective dispersion of thermal conductive fillers is a prerequisite for ensuring thermally conductive networks formed in polymer composites. In this work, a facile method was provided by using cellulose to alter the distribution state of boron nitride (BN) for the preparation of high thermally conductive polylactic acid (PLA). After powder mixing and hot‐pressing process, the Cellulose@BN was located at the boundaries of PLA granules to form consecutive thermally conductive networks with more compact structure. Morphology observation and FTIR spectra confirmed that BN edges absorbed on the cellulose surface under the intermolecular hydrogen bond interaction between PLA and BN. At the BN content of 25 wt%, contrasted with traditional BN/PLA segregated polymer composites (SPCs), thermal conductivity coefficient of Cellulose@BN/PLA SPCs improved by 53.5% from 0.71 to 1.09 Wm−1 K−1. This enhancement could be attributed to the reason that the cellulose regulated stripe aggregation allowed the BN connect with each other more compact, thus a thermal conduction networks with reduced phonon scattering were formed.
Fundamental control of grade‐specific colorectal cancer morphology by Src regulation of ezrin–centrosome engagement
Authors: Rainey Lisa , Deevi Ravi K , McClements Jane , Khawaja Hajrah , Watson Chris J , Roudier Martine , Van Schaeybroeck Sandra , Campbell Frederick C
Published: April 2020

The phenotypic spectrum of colorectal cancer (CRC) is remarkably diverse, with seemingly endless variations in cell shape, mitotic figures and multicellular configurations. Despite this morphological complexity, histological grading of collective phenotype patterns provides robust prognostic stratification in CRC. Although mechanistic understanding is incomplete, previous studies have shown that the cortical protein ezrin controls diversification of cell shape, mitotic figure geometry and multicellular architecture, in 3D organotypic CRC cultures. Because ezrin is a substrate of Src tyrosine kinase that is frequently overexpressed in CRC, we investigated Src regulation of ezrin and morphogenic growth in 3D CRC cultures. Here we show that Src perturbations disrupt CRC epithelial spatial organisation. Aberrant Src activity suppresses formation of the cortical ezrin cap that anchors interphase centrosomes. In CRC cells with a normal centrosome number, these events lead to mitotic spindle misorientation, perturbation of cell cleavage, abnormal epithelial stratification, apical membrane misalignment, multilumen formation and evolution of cribriform multicellular morphology, a feature of low‐grade cancer. In isogenic CRC cells with centrosome amplification, aberrant Src signalling promotes multipolar mitotic spindle formation, pleomorphism and morphological features of high‐grade cancer. Translational studies in archival human CRC revealed associations between Src intensity, multipolar mitotic spindle frequency and high‐grade cancer morphology. Collectively, our study reveals Src regulation of CRC morphogenic growth via ezrin–centrosome engagement and uncovers combined perturbations underlying transition to high‐grade CRC morphology. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
Low prenatal detection rate of valvar pulmonary stenosis: What are we missing?
Authors: Ronai Christina , Freud Lindsay R. , Brown David W. , Tworetzky Wayne
Published: April 2020

Objectives

Critical pulmonary stenosis (PS) and pulmonary atresia with intact ventricular septum (PAIVS) require urgent neonatal intervention. Since PS may be more insidious than PAIVS during gestation, we hypothesized that neonates with PS would have lower rates of prenatal detection than PAIVS.

Methods

We performed a retrospective chart review of all neonates who underwent diagnostic or interventional cardiac catheterization between 2000 and 2014 for critical PS or PAIVS. The rates of prenatal diagnosis were calculated for PS and PAIVS. Prenatal and postnatal echocardiographic data were reviewed.

Results

178 patients met inclusion criteria: 91 with critical PS and 87 with PAIVS. The prenatal diagnosis rate for critical PS was lower than for PAIVS at 37% (34/91) vs 60% (52/87) (P = .003). At the time of diagnosis at a median gestational age of 25 weeks, the median TV z‐score for patients with critical PS was larger than in PAIVS (−0.15 vs −3.0 P = .004).

Conclusion

Critical PS had a lower prenatal detection rate than PAIVS, likely due to a relatively normal 4‐chamber view at the time of routine second trimester screening in patients with PS. Color flow Doppler of the outflow tracts may improve detection, since outflow tracts may appear normal by 2D imaging.
Advances and approaches for chemical recycling of plastic waste
Authors: Thiounn Timmy , Smith Rhett C.
Published: April 2020

The global production and consumption of plastics has increased at an alarming rate over the last few decades. The accumulation of pervasive and persistent waste plastic has concomitantly increased in landfills and the environment. The societal, ecological, and economic problems of plastic waste/pollution demand immediate and decisive action. In 2015, only 9% of plastic waste was successfully recycled in the United States. The major current recycling processes focus on the mechanical recycling of plastic waste; however, even this process is limited by the sorting/pretreatment of plastic waste and degradation of plastics during the process. An alternative to mechanical processes is chemical recycling of plastic waste. Efficient chemical recycling would allow for the production of feedstocks for various uses including fuels and chemical feedstocks to replace petrochemicals. This review focuses on the most recent advances for the chemical recycling of three major polymers found in plastic waste: PET, PE, and PP. Commercial processes for recycling hydrolysable polymers like polyesters or polyamides, polyolefins, or mixed waste streams are also discussed.
Electron ionization mass spectrometric fragmentation and detection of autoxidation products of 2,6,10,14‐tetramethyl‐7‐(3‐methylpent‐4‐enyl)‐pentadec‐5‐ene in Arctic sediments
Authors: Rontani Jean‐François , Smik Lukas , Belt Simon T.
Published: April 2020

Rationale

Some highly branched isoprenoid (HBI) alkenes are commonly used as proxies for palaeoceanographic reconstructions. However, there is a need to identify compounds that are sufficiently stable and abundant to be used as tracers of HBI oxidation in sediments. 2,6,10,14‐Tetramethyl‐7‐(3‐methylpent‐4‐enyl)‐pentadec‐5(Z/E)‐en‐4‐ols resulting from 2,6,10,14‐tetramethyl‐7‐(3‐methylpent‐4‐enyl)‐pentadec‐5‐ene appear to be useful for this purpose.

Methods

Comparison of electron ionization (EI) mass spectra and retention times with those of standards allowed formal identification of autoxidation products of 2,6,10,14‐tetramethyl‐7‐(3‐methylpent‐4‐enyl)‐pentadec‐5‐ene. EI‐MS fragmentations of TMS ethers of the main oxidation products (2,6,10,14‐tetramethyl‐7‐(3‐methylpent‐4‐enyl)‐pentadec‐5(Z/E)‐en‐4‐ols) were deduced by gas chromatography/electron ionization mass spectrometry (GC/EI‐MS), low‐energy collision‐induced dissociation tandem mass spectrometry (CID‐MS/MS) and accurate mass measurements. These compounds were then quantified in Arctic sediment samples in MS/MS multiple reaction monitoring (MRM) mode using transitions based on the main fragmentation pathways elucidated.

Results

2,6,10,14‐Tetramethyl‐7‐(3‐methylpent‐4‐enyl)‐pentadec‐5(Z/E)‐en‐4‐ols were identified after autoxidation of the HBI alkene 2,6,10,14‐tetramethyl‐7‐(3‐methylpent‐4‐enyl)‐pentadec‐5‐ene. Low‐energy CID‐MS/MS analyses and accurate mass measurements allowed the EI‐MS fragmentation pathways of their trimethylsilyl (TMS) derivatives to be elucidated. Some specific fragment ions and chromatographic retention times were also useful for further characterization. As an application of some of the described fragmentations, TMS derivatives of these metabolites were characterized and quantified in MRM mode in Arctic sediments.

Conclusions

Due to their production in high proportions during autoxidation of their parent HBI diene, their apparent stability in sediments, and their specific EIMS fragmentations, (Z and E)‐2,6,10,14‐tetramethyl‐7‐(3‐methylpent‐4‐enyl)‐pentadec‐5‐en‐4‐ol TMS derivatives appeared to be useful tracers of HBI autoxidation in sediments.
Anticancer Activity Screening of a Series of Imidazo[2,1‐c][1,2,4]triazolone and Imidazo[1,2 ‐b][1,2,4]triazolone Derivatives Synthesized Under Solvent Free Conditions
Authors: Hassan Aisha Y. , Sarg Marwa T. , El Deeb Moshira A. , El Rabeeb Shaimaa I.
Published: April 2020

In this approach we applied a green synthetic protocol for the preparation of a novel series of imidazotriazole derivatives under solvent free conditions and shorter reaction times utilizing the reactive 2‐thioxoimidazolidinone derivative 1 as a starting substrate. Different substituted imidazo[2,1‐c][1,2,4]triazolone derivatives 2–4,6 and imidazo[1,2‐b][1,2,4]triazolone derivatives 8–10, 12, 13, 15, 16 and 18 were synthesized. We carried out the synthesis of the open chain analogues phenylimidazolidin‐2‐ylidenepicolinohydrazide 5, dihydroimidazolylacetamide 11, imidazolylpicolinamide 14, pentahydroxyhexylideneaminoimidazol‐5‐one derivative 17, dihydroimidazolyl‐N,N‐dimethylformimidamide 19 and the dihydroimidazo[1,2‐b][1,2,4]triazepine‐7‐carbonitrile 20. The synthetic methods involved mainly fusion of compound 1 with the appropriate reagents. The in vitro anticancer evaluation at the National Cancer Institute (NCI), USA at a single dose (10−5 M) in full NCI 60 cell panel revealed that a significant inhibition for some cancer cells was observed with compounds 11 and 17–19 (38–67.5 % inhibition).These novel compounds displayed appreciable anticancer activities against different cancer cell lines including leukemia, colon cancer, melanoma, ovarian cancer, renal cancer and non‐small cell lung cancer cell lines.
Palladium Acetate/[CPy][Br]: An Efficient Catalytic System towards the Synthesis of Biologically Relevant Stilbene Derivatives via Heck Cross‐Coupling Reaction.
Authors: Ramsingh Girase Tejpalsingh , Patil Kesharsingh J. , Kapdi Anant R. , Gupta Gaurav R.
Published: April 2020

The main objective of this study was to replace the traditionally applicable volatile organic solvents and imidazolium‐based ionic liquid solvents with thermally stable surfactant, cetylpyridinium bromide as surfactant ionic liquid (SIL) and examine the potential of the same as viable reaction medium in the synthesis of stilbenes, quinoxaline and pyridone decorated substratesviaHeck cross‐coupling reaction. This work thoroughly investigates the thermal, spectral and morphological properties of cetylpyridinium bromide as surfactant ionic liquid. Cetylpyridinium bromide is a well‐known germicide with well‐established degradation mechanism and displays remarkable solvent properties for the homogeneously catalysed Heck cross‐coupling reactions, which is of great significance to enlarge the applications window of cetylpyridinium bromide from biologically significant surfactant material to the choice of solvent in synthetic organic chemistry.
Synthesis of Modified TiO2 Nanoparticles with Polyacrylonitrile and Poly(hydroxyethyl acrylate) via ATRP
Authors: Wang Yazhen , Liu Li , Jiang Shengyue , Li Shuang , Lan Tianyu , Zu Liwu , Dong Shaobo
Published: April 2020

The modified TiO2 nanoparticles (TiO2 NPs) with diblock copolymer were successfully synthesized via surface‐initiated atom transfer radical polymerization (SI‐ATRP). The modified TiO2 contained the ‐NH2 group (TiO2‐APTES) was obtained by 3‐aminopropyltriethoxysilane (APTES) as a coupling agent. Bromine modified TiO2 NPs (TiO2‐Br), the ATRP initiator was prepared by the reaction of ‐NH2 in TiO2‐APTES with 2‐bromoisobutyryl bromide (BiBB). The block copolymer of the polyacrylonitrile and poly(hydroxyethyl acrylate) (PAN‐b‐PHEA) on the TiO2 surface was synthesized with TiO2‐Br as initiator via ATRP. The differential scanning calorimetry (DSC) analysis revealed two Tg values corresponding to two blocks, which indicated two polymer chains of the modified TiO2. The result of Gel Permeation Chromatography (GPC) shown increasing molecular weight of the PAN‐b‐PHEA also demonstrated the block copolymer structure.
Protection and Activation of Hydroxycinnamic Acids in Water
Authors: DellaGreca Marina , Longobardo Luigi
Published: April 2020

Hydroxycinnamic acids such as p‐coumaric, ferulic, sinapic and caffeic acids were protected as carbonates and activated as mixed carbonic anhydrides in water at RT by adding a base and isobutyl chloroformate. These anhydrides were used for amine and C‐protected α‐amino acid acylation to give O‐carbonate protected phenolic amides. Acylation of free α‐amino acids was performed in acetone‐water in high yields producing the O‐carbonate protected N‐hydroxycinnamoyl‐α‐amino acids. Pure derivatives were obtained in many cases directly by crystallization. Free phenolic compounds were rapidly obtained by carbonate deprotection with piperidine. The method offers a novel route for amide bond formation in water and the direct functionalization of hydroxycinnamic acid families with free α‐amino acids, providing a facile preparation of precious natural bioactive derivatives.
Manganese Trioxide with Various Morphologies: Applications in Catalytic Dye Degradation
Authors: Alwera Vijay , Singh Seema , Srivastava Vimal C. , Mandal Tapas K.
Published: April 2020

Hierarchical manganese trioxides (Mn2O3) with different morphologies are prepared by thermal treatment of carbonate precursors synthesized using a facile and template‐free hydro‐solvothermal method. Various morphologies of Mn2O3 have evolved as a function of precursor salts keeping the solvent system and temperature of synthesis intact. On hydro‐solvothermal treatment, manganese carbonate with different microstructures is formed first and on subsequent calcination at 500 °C, the carbonates are converted into manganese trioxide with the retention of the initial microstructure. While formation of Mn2O3 microcubes is achieved with MnCl2 and Mn(NO3)2 as precursor salts, microspheres and microflakes are obtained with Mn(OAc)2 and MnC2O4 precursors, respectively. The average microcrystal size varied from ∼ 10–20 (±5) μm with somewhat high surface areas. The catalytic dye degradatin studies conducted on Mn2O3 microcubes and microspheres in aqueous acidic mediums show rapid removal of dyes in the dark. While an aqueous acidic solution of methyl orange (MO) is decolorized in 2 min, more than 90 % of rhodamine B (RhB) and methylene blue (MB) are degraded within 50–60 min. Retention of catalytic activity after five cycles indicates their reusability and promise as simple binary oxide catalysts for wastewater treatment.
Multifunctional Mesoporous CDQs/BMMs with Strong Fluorescent Property and Sustained Drug Releasing Performance
Authors: Li Junfang , Sun Jihong , Bai Shiyang , Wu Xia
Published: April 2020

A multifunctional mesoporous CQDs/BMMs with strong fluorescent property was synthesized via a facile and reliable sol‐gel approach to dope carbon quantum dots (CQDs) into the bimodal mesopores silica (BMMs) for application in sustained drug releasing performance. In which, the influences of various parameters, including hydrothermal system (glucose concentration, temperature, and time) and removing cetyltrimethyl ammonium bromide (CTAB) conditions (ethanol‐HCl, isopropanol‐H2O, and acetone) on fluorescence performances and structure properties were investigated via PL, UV, XRD, BET, SEM, TEM, EDS, FT‐IR, XPS, TG. The result showed that the resultant CQDs/BMMs possesses uniform mesopore structure with larger specific surface area of around 752 m2 g−1, and excitation‐independent emission properties at the strongest emission peak of 488 nm. Using ibuprofen as a model drug, their drug delivery behaviours were assessed by UV and mass balance equation, showing a high loading amount (154.3 mg g−1 within 20 min) and good sustained release performance along with stable and strong fluorescence.
Synthesis and Antibacterial Activity of New Chiral Aminoalcohol and Benzimidazole Hybrids
Authors: Çiçek İlknur , Tunç Turgay , Ogutcu Hatice , Abdurrahmanoglu Suzan , Günel Aslıhan , Demirel Nadir
Published: April 2020

New chiral aminoalcohol‐benzimidazole hybrids have been synthesized from commercially available aminoalcohols

[S(+)‐Phenylglycinol, S(−)‐ Phenylalaninol and S(+)‐ Leuicinol] and 2‐(chloromethyl)‐N‐tosyl‐1‐H‐benzimidazole. The synthesized compound were characterized by IR, NMR, and LC‐MS analysis. The antibacterial properties of aminoalcohol‐benzimidazole hybrid molecules 4 a, 4 b, and 4 c were investigated against both gram (+ve) and gram (‐ve) bacterial pathogens by the well‐diffusion method using several standarts. The cell‐based biological experiment was consistent with in silico studies. Furthermore, in silico studies revealed that all synthesized compounds could be suggested as potential drugs for inhibition of both peptide deformylase for bacteria and sterol 14α‐demethylase for yeast.
Synthesis, Crystal Structure and Computational Investigation of New 4‐Phenyl‐decahydro‐1H‐1,5‐benzodiazepin‐2‐one as Potent Inhibitor of Mu‐opioid Receptor
Authors: Garadi Wedad Al , Bakri Youness El , Lai Chin‐Hung , Karthikeyan Subramani , Ghayati Lhoussaine El , Mague Joel T. , Essassi El Mokhtar
Published: April 2020

A novel benzodiazepine derivative was prepared and characterized by elemental analysis, FT‐IR, NMR (1H and 13C) and HR‐MS methods. Its crystal structure was also investigated by single crystal X‐ray diffraction. In the title compound, the fused 6‐ and 7‐membered rings adopt chair and “twist boat” conformations, respectively. In the crystal, the molecules form inversion dimers through N—H⋅⋅⋅O hydrogen bonds and pack with no unusually short intermolecular contacts, which is in agreement with the results of the Hirshfeld surface analysis. The Hirshfeld surface analysis showed that the H⋅⋅⋅H contact was the most important interaction for the studied compound. Based on the DFT−B3LYP study, the studied compound owned a little different geometry in the gas phase concerning the solid phase. The molecular docking was performed between the title compound and a mu‐opioid receptor. Molecular dynamics studies were also carried up to 50 ns to understand the stability for the title compound complex with the mu‐opioid receptor.
Ag Nanoparticles/AgX (X=Cl, Br and I) Composites with Enhanced Photocatalytic Activity and Low Toxicological Effects
Authors: Assis Marcelo , Groppo Filho Francisco C. , Pimentel Dayene S. , Robeldo Thaiane , Gouveia Amanda F. , Castro Tassia F. D. , Fukushima Hirla C. S. , de Foggi Camila C. , da Costa João P. C. , Borra Ricardo C. , Andrés Juan , Longo Elson
Published: April 2020

Periodic structures induced by electron irradiation are a unique phenomenon when electron beams irradiate on the surface of some materials. These periodic structures have potential for technological applications. However, the fuzzy nature of the electron‐induced structuring hinders its further exploration in such applications. In this paper, novel Ag nanoparticle/AgX (X=Cl, Br and I) composites, with enhanced photocatalytic activity and low toxicological effects, were prepared, for the first time, using electron beam irradiation. The remarkable advantage of this approach is that the Ag nanoparticles/AgX composites can be easily prepared in one‐step without the need for high‐pressure conditions, surfactants, ionic liquids, or reducing agents. Furthermore, our method does not involve any toxic substances, which makes the as‐synthesized samples highly applicable for technological applications. The structure, morphology and physicochemical properties of the Ag nanoparticles/AgX composites were studied using various characterization techniques. Using first‐principles calculations based on density functional theory and the quantum theory of atoms in molecules, we reveal how the concentration of excess electrons in the AgX materials induces the formation of the Ag nanoparticles under electron beam irradiation. These results extend the fundamental understanding of the atomic process underlying the mechanism of Ag−X bond rupture observed during the transformation induced via electron irradiation of the AgX crystals by increasing the total number of electrons in the bulk structure. Thus, our findings provide viable guidance for the realization of new materials for the degradation of contaminated wastewater with low toxicity.
High Stability of Immobilized Acetylcholinesterase on Chitosan Beads
Authors: Işık Mesut
Published: April 2020

The enzymes are unstable and have a short lifetime; this causes a decrease in the number of enzyme usage and increases the cost. In the study, the acetylcholinesterase (AChE) enzyme was covalently immobilized to the surface of chitosan via glutaraldehyde by cross‐linking method, where glutaraldehyde contains functional amine group. The immobilized enzyme was characterized by scanning electron microscopy‐energy dispersive X‐ray analysis (SEM‐EDX). The operational and storage stability of immobilized AChE was found higher than the free enzyme by the spectrophotometric method. The storage stability of the immobilized AChE was found 81% for 60 days, while the free AChE lost a high ratio of its activity in 30 days. It was observed that 93% activity was preserved for the immobilized enzyme after reusing it approximately 30 times. Moreover, kinetic parameters, the Km and Vmax, were found 0.073 mM and 0.244 EU/mL for immobilized AChE and 0.044 mM and 0.362 EU/mL for free AChE, respectively. The AChE enzyme is used in the analysis of pesticides; that is why the high stability and reusability of the enzyme as a result of immobilization proses are important in biotechnological applications.
Pantoprazole Derivatives: Synthesis, Urease Inhibition Assay and In Silico Molecular Modeling Studies
Authors: Azizian Homa , Esmailnejad Atefeh , Fathi Vavsari Vaezeh , Mahernia Shabnam , Amanlou Massoud , Balalaie Saeed
Published: April 2020

A number of pantoprazole derivatives were synthesized and screened for their urease inhibitory properties. Some of them showed potent inhibitions against jack bean urease. All compounds showed varying degree of IC50 in the range of 25.85 to 181 μMol as compared to standard acetohydroxamic acid (AHA) (100±2.02 μMol). Derivatives bearing 5‐aryl‐1,3,4‐oxadiazole ring substitutions (aryl= pyrazyl, pyridyl and phenyl) were found to be more potent inhibitors than AHA and pantoprazole. The most promising compound, 2‐((3,4‐dimethoxypyridin‐2‐yl)methylthio)‐5‐(pyrazin‐2‐yl)‐1,3,4‐oxadiazole 12, with IC50 value of 25.85±1.21 showed remarkable urease inhibition activity. In silico molecular modeling investigation performed to rationalize the possible binding interaction and ADME properties of compounds over the active site of urease enzyme. The induced fit docking study showed that compound 12 interacted with conserved residues His593 and Arg609 located at the mouth of the urease active site flap and are essential for enzyme catalytic activity. These target compounds could be further studied as a lead skeleton for discovery of novel urease inhibitors.
Preparation of Curcubit[6]uril functionalized CuO Nanoparticles: A New Nanosensing Scheme Based on Fluorescence recovery after FRET for the Label Free Determination of Dopamine
Authors: Qasem Mayada , El Kurdi Riham , Patra Digambara
Published: April 2020

In this manuscript, the aim is to functionalize CuO nanoparticles with the supramolecular host molecule, in this case curcubit[6]uril to have a host guest interaction between the CuO nanoparticles and probe (guest) molecules. Acridine Orange (AO) is applied as a guest molecule. Acridine orange binds with curcubit[6]uril via its carbonyl rims. In the presence of curcubit[6]uril conjugated CuO nanoparticles, the fluorescence intensity of AO is quenched by the CuO NPs through fluorescence resonance energy transfer phenomenon. However, dopamine adsorbs on the surface of CuO nanoparticles by getting incorporated into CB[6] host molecules and kicks out AO from curcubit[6]uril pocket, thus, discouraging fluorescence resonance energy transfer phenomenon and thus enhancing fluorescence intensity of AO by a factor of 3. This fluorescence recovery has been utilized to design a new detection system for dopamine. The assay, measured at fluorescence excitation and emission wavelengths of 480 nm and 520 nm respectively, works in the 0–40 μM concentration range of dopamine with 40 nM limit of detection. This method is not interfered by ascorbic acid, uric acid, glucose, tryptophan and acetaminophen. The proposed method provides a good recovery from synthetic samples and shows good stability.
A New Facial Homoleptic Tris‐cyclometalated Iridium(III) Complex with Oxygen‐bridged Triarylamine Units
Authors: Zhang Xinghua , Cao Yibo , Song Jialiang , Li Kang , Jiang Qibin , Yuan Aihua , Shi Chao
Published: April 2020

A new facial homoleptic tris‐cyclometalated phosphorescent iridium(III) complex Ir(ppyNO)3 featuring three oxygen‐bridged triarylamine units has been synthesized via an efficient Suzuki–Miyaura cross‐coupling reaction of oxygen‐bridged triarylamine unit based boron reagent 1‐b with corresponding tribrominated iridium(III) complex Ir‐Br. It can not only show an effective green light emission, but also display a narrower full width at half maximum (FWHM=57 nm) and better solubility than that of the classical complex fac‐Ir(ppy)3 (FWHM=82 nm, ppy=2‐phenylpyridine). Furthermore, a longer emission lifetime (τ=1201 ns) of Ir(ppyNO)3 in polystyrene (PS) film can be found than that (τ=45 ns) in CH2Cl2 solution. In addition, the lowest triplet state (T1) of Ir(ppyNO)3 can exhibit both metal‐to‐ligand charge transfer (3MLCT) and intraligand charge transfer (3ILCT) excited state character according to DFT calculations.
Interaction of a Weak Acid Cation Exchange Resin (Dowex Mac 3H) with the Belousov‐Zhabotinsky Reaction and Estimation of Metal Ions
Authors: Rashid Sna , Ganaie Nadeem B. , Peerzada Ghulam M.
Published: April 2020

The work pertains to the study on direct and indirect interaction of a macroporous weak acid cation exchange resin‐Dowex Mac 3H form with Belousov‐Zhabotinsky (BZ) reaction based on malonic acid‐cerium‐bromate‐sulfuric acid system. In the direct mode, the above reaction was perturbed by adding 10% (w/w) of Dowex Mac 3H at three different time intervals, i. e., before the start of induction period, during the induction period and after the commencement of oscillations. This mode of interaction was studied to investigate the effect of heterogeneity on the dynamics of BZ reaction. The indirect interaction of the resin was studied by interacting the resin individually with the optimized metal catalyst for a particular period of time after which the supernatant was used as initial reagent in the otherwise optimized BZ system. The interaction was monitored with respect to the change in oscillatory parameters before and after loading the resin with metal catalyst. The selectivity of the resin towards cerium and iron (ferroin) was studied through the said BZ reaction using potentiometry as the main technique. It was found that resin is more selective towards ferroin. The selectivity of the resin towards the various metal ions was followed by their estimation using UV‐Visible spectrophotometry. The effect of solvents on the ion exchange capacity (IEC) of the resin was also studied through the BZ reaction. Some solvents increased its IEC while others decreased it. The potentiometric results obtained were validated by spectroscopic findings and electrochemical studies.
Water‐Promoted Synthesis of Azepino[3,4,5‐cd]indole Analogues via Pictet‐Spengler Reaction
Authors: Zhang Shuaizhong , Cai Yunrui , Zou Hongbin
Published: April 2020

Pictet‐Spengler reaction is an important strategy for the chemical or biosynthetic construction of alkaloids. Various suitable catalysts have thus been developed to drive the reaction. We herein report for the first time that water could directly catalyze the Pictet‐Spengler reactions of 2‐(1H‐indol‐4‐yl)ethanamines with aldehydes or ketones to generate azepino[3,4,5‐cd]indoles. Notably, this protocol is environmentally benign and highly practical with a wide substrate scope and promising gram‐scale applications. A plausible mechanism for this catalytic reaction is proposed to provide insights and potentially open a new avenue for organic synthesis.
Electrochemically Oxidative Coupling of S‐H/S‐H for S‐S Bond Formation: A Facile Approach to Diacid‐disulfides
Authors: Sun Xue‐Jie , Yang Shang‐Feng , Wang Zhi‐Tong , Liang Sen , Tian Hong‐Yu , Yang Shao‐Xiang , Liu Yong‐Guo , Sun Bao‐Guo , Zeng Cheng‐Chu
Published: April 2020

A green electrochemical method of preparing diacid‐disulfides has been developed, in which an S−S bond is formed by electrochemically oxidative coupling of S−H/S−H employing redox active NaI as mediator. The reactions are carried out in a simple undivided cell under constant current condition at room temperature and complete in 1.3 h to afford a series of diacid‐disulfides with up to 97 % yields.
Silver Nanoparticles Derived from Albizia lebbeck Bark Extract Demonstrate Killing of Multidrug‐Resistant Bacteria by Damaging Cellular Architecture with Antioxidant Activity
Authors: Das Mahapatra Ananya , Patra Chiranjit , Mondal Joy , Sinha Chittaranjan , Chandra Sadhukhan Provash , Chattopadhyay Debprasad
Published: April 2020

Silver nanoparticles (Ag‐NP‐AE) are synthesized and stabilized by the extract of an ethnomedicine, Albizia lebbeck bark aqueous extract (AE). Ag‐NP‐AE is active against several multidrug‐resistant (MDR) clinical isolates. The nanoparticles are characterized by UV‐vis spectroscopy, Fourier‐transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), Scanning electron microscope (SEM), Transmission electron microscope (TEM) and X‐ray diffraction (XRD) studies. The antibacterial potency of Ag‐NP‐AE is determined by Disc diffusion, Agar and Broth dilution assays against 14 MDR isolates along with their minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The growth kinetics was determined by quantification of colonies; while toxicity by quantification of viable cells. The Ag‐NP‐AE shows free‐radical scavenging activity at 15–20 μM and is non‐toxic up to 50 μM but demonstrated significant antibacterial activity against all the test isolates with zone diameter of 10.4–19.5 mm and MIC of 0.5–0.84 μM (0.085‐0.143 μg); while the zone diameter with AE was 10.2–15 mm and MIC of 128–1024 μg/mL, respectively; while 100 % killing was observed at 0.50 μM within 2–4 h of exposure due to damage of cellular architectures.
Electric Field Effects on the Adsorption of Dopamine Species on Ag(111): DFT Investigation of Interaction Mechanism
Authors: Rossi‐Fernández Ana C. , Meier Lorena A. , Domancich Nicolás F. , Castellani Norberto J.
Published: April 2020

The study of interactions between dopamine (DA) and noble metal surfaces as Ag, is envisaged as a fundamental factor to attain more efficient electrochemical sensor materials. We describe, in the framework of Density Functional Theory, the adsorption of four dopamine species, neutral (NDA), zwitterionic (ZDA), protonated (PDA) and deprotonated (DPDA) species on Ag(111), upon the application of an external electric field (E), a fact of pertinence for electrochemistry tests. The ZDA and PDA species show relatively large binding energies of about 2.9 eV to 4.6 eV and suffer a significant flatting upon adsorption, compared with DPDA and NDA. The adsorbates binding energy is an increasing function of the applied E for ZDA and PDA species, showing a great change when the results for positive and negative E are compared. An electron transfer is produced from NDA, ZDA and PDA species to Ag, while in the case of DPDA an opposite behavior is obtained. As the sign of E is modified, an increase of charge values in all DA species is observed. The theoretical results obtained here show that ZDA and PDA species are the most affected DA species upon adsorption on Ag(111) and when non‐zero electric fields are applied.
The association of occupational stress and sleep duration with anxiety symptoms among healthy employees: A cohort study
Authors: Kim Sun‐Young , Shin Young‐Chul , Oh Kang‐Seob , Shin Dong‐Won , Lim Weon‐Jeong , Kim Eun‐Jin , Cho Sung Joon , Jeon Sang‐Won
Published: April 2020

The aim of this study is to identify occupational stress associated with the development of new‐onset anxiety symptoms and the dose–response relationship between sleep duration and the onset of anxiety symptoms. Data from 29,251 healthy employees who had undergone at least two comprehensive health examinations at Kangbuk Samsung Hospital Health Screening Center were analysed. Anxiety symptoms were assessed using the Beck Anxiety Inventory. Occupational stress and sleep duration were measured using a self‐reported questionnaire about total sleep time and the Korean Occupational Stress Scale‐Short Form (KOSS‐SF), respectively. Flexible parametric proportional hazards model used to estimate the hazard ratios. Compared with the groups without case‐level anxiety, discomfort in an organizational climate, high job demands, job insecurity, organizational injustice and lack of reward were associated with the onset of case‐level anxiety. Compared with less than 6 hr of sleep per day, the beneficial level of sleep duration was 7 ≤ to <9 hr a day. Almost all subscales of job stress were associated with the development of anxiety symptoms. In addition, the efficacious level of sleep duration for reducing the onset of future anxiety symptoms was 7 ≤ to <9 hr a day.
Global software development governance: Challenges and solutions
Authors: Manjavacas Antonio , Vizcaíno Aurora , Ruiz Francisco , Piattini Mario
Published: April 2020

Global software development (GSD) has become a rising software development model in the last few years. Although much research has been performed in terms of GSD management, GSD governance research is scarce at the present time and presents multiple challenges that need to be addressed. In this paper, a systematic mapping study has been conducted, the aim of which was to discover the main issues dealt with in GSD governance literature, as well as to point out the particular research gaps that are still present in this domain. This allowed us to find out new challenges to be addressed, along with possible solutions to these. The results reveal a lack of research in key aspects such as tools, culture, people, and information, all of which provides a great opportunity for future approaches while also highlighting new opportunities in GSD governance research.
Trajectory functional boxplots
Authors: Yao Zonghui , Dai Wenlin , G. Genton Marc
Published: April 2020

With the development of data‐monitoring techniques in various fields of science, multivariate functional data are often observed. Consequently, an increasing number of methods have appeared to extend the general summary statistics of multivariate functional data. However, trajectory functional data, as an important subtype, have not been studied very well. This article proposes two informative exploratory tools: the trajectory functional boxplot and the modified simplicial band depth (MSBD) versus wiggliness of directional outlyingness (WO) plot, to visualize the centrality of trajectory functional data. The newly defined WO index effectively measures the shape variation of curves and hence serves as a detector for shape outliers; additionally, MSBD provides a centre‐outward ranking and works as a detector for magnitude outliers. Using these two measures, the functional boxplot of the trajectory reveals centre‐outward patterns and potential outliers using the raw curves, whereas the MSBD‐WO plot illustrates such patterns and outliers in a space spanned by MSBD and WO. The proposed methods are validated on hurricane path data and migration trace data recorded from two types of birds.
Relating and comparing methods for detecting changes in mean
Authors: Fearnhead Paul , Rigaill Guillem
Published: April 2020

In recent years, there have been a large number of proposed approaches to detecting changes in mean. A natural question for an analyst is which method is most appropriate for their applications. Answering this question is difficult because current empirical studies often give conflicting conclusions. This paper aims to show the similarities and differences between different changepoint methods. We highlight that there are two aspects to estimating changepoints: estimating the number of changes and estimating their locations, and that comparisons should separately evaluate these two aspects. We perform an extensive comparison of different methods across a range of simulation scenarios and provide code and full results for an interested practitioner to extend this comparison to more methods or different scenarios.