bluuebunny/crossref_metadata_2025 huggingface dataset:
The Stability Evaluation of Two Internal Fixation Patterns of Extracapsular Condylar Fracture Based on One Novel Measuring Method
Authors: Liao Qian , Liang Zhuangzhuang , Zhang Peng , Xu Bing , Gui Haijun
Published: July 2020

Purpose:

The most stable internal fixation pattern for extracapsular condylar fracture (ECF) has been controversial. In this study we aimed to evaluate the stability of 2 common internal fixation patterns using 1 or 2 miniplates separately. One novel measuring method based on the angle of miniplates’ localization was introduced.

Materials and Methods:

Twenty-seven patients with 30 sides of extracapsular condylar fracture were enrolled in this retrospective study. All cases were performed open reduction and internal fixation using 1 or 2 titanium plates with both the postoperative immediate CT (T1) and the over 6 months’ follow-up CT (T2). Mandibles and implants were segmented and reconstructed respectively using SIMPANT 14.04 software. For 1 miniplate group, the sagittal crossing angle (<1) between miniplate (P1) and posterior border of ipsilateral ramus was measured. For 2 miniplates group, the sagittal crossing angle (<2) between 2 miniplates (P2a, P2b) was measured. Both anteroposterior (∠AP) and mediolateral angle change (∠ML) of each miniplate between T1 and T2 was measured. The stability of 2 internal fixation patterns was measured and evaluated based on the angle change of miniplates. And also the stability of each internal fixation pattern could be investigated based on the relationship between the placement patterns of miniplates and the angle change.

Results:

Fifty-two miniplates were finally segmented and reconstructed successfully, including 8 of 1 miniplate group and 44 of 2 miniplate group. For 1 miniplate group, the average ∠AP and ∠ML were 6.10° and 8.54°, respectively. For 2 miniplate group, the average ∠AP and ∠ML of P2a were 3.02° and 2.56°, respectively, as well as 3.12° and 3.07° of P2b.

Conclusions:

The novel measuring method based on the angle of miniplates’ localization showed potential for the stability evaluation of internal fixation of condylar fracture. In summary, the internal fixation patterns using 2 miniplates shows better stability than that of 1 miniplate.
The Initial Experience on Thoracoscopic Sleeve Lobectomy: Continuous Suturing Technique of the Bronchial Anastomosis in 12 Cases
Authors: Ceylan Kenan C. , Acar Arkin , Örs Kaya Şeyda
Published: July 2020

Background:

Sleeve resection is a widely performed type of operation in the surgical treatment of non–small cell lung cancer. Video-assisted thoracoscopic surgery (VATS) is now used even in central tumor surgeries of the lung with the increasing technology and experience. Sleeve resection cases performed through VATS in our clinic in recent years were presented with demographic, surgical, pathologic, and survey characteristics.

Materials and Methods:

Twelve patients who underwent sleeve resection with VATS in our clinic between November 2015 and August 2019 were included in the study. Operative, pathologic, and postoperative characteristics of the patients were examined.

Results:

A total of 12 patients, 3 female and 9 male individuals, were included in the study. The mean age of the patients was 61.7±12.9 years. According to the localization of the tumors, left upper lobectomy was performed in 4 patients and 8 patients underwent right upper lobectomy. During the sleeve anastomosis of the patients, 3/0 prolene sutures were used in 5 patients (36%) and 4/0 prolene sutures in 4 patients (36%), whereas 3/0 polydioxanone suture (PDS) was used in 3 patients (28%). The mean operation time was 288.2±77.1 (205 to 460) minutes and the mean anastomosis time was 70±18.5 (55 to 110) minutes. In the postoperative period, 1 patient who had acute myocardial infarction died on the fourth postoperative day. The mean postoperative drainage duration of the patients was 5.5±1.9 (3 to 10) days and the mean length of hospital stay was 6.4±1.9 (4 to 11) days. When the pathologic features were examined, the mean tumor diameter was found to be 2.5±1.2 (1 to 5.5) cm. The mean follow-up period was calculated as 26.1±15.6 months (2 to 47). Other than 1 patient who died, the follow-up of 11 patients still proceeds.

Conclusions:

VATS approach of sleeve resections, which is performed cautiously even by thoracotomy, is becoming more common. These operations, which could be performed in experienced centers, offer a postoperative period of less morbidity to the patients with the advantage of reduced postoperative pain, drainage time, and hospital stay.
Five-Year Weight Loss Outcomes in Laparoscopic Vertical Sleeve Gastrectomy (LVSG) Versus Laparoscopic Roux-en-Y Gastric Bypass (LRYGB) Procedures: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Authors: Osland Emma J. , Yunus Rossita M. , Khan Shahjahan , Memon Muhammed A.
Published: July 2020

Background:

Laparoscopic vertical sleeve gastrectomy (LVSG) has overtaken the laparoscopic Roux-en-Y gastric bypass (LRYGB) as the most frequently performed bariatric surgical procedure. To date little has been reported on the long-term outcomes of the LVSG procedure comparative to the traditionally favoured LRYGB. We undertook a systematic review and meta-analysis to review the 5-year outcomes of comparing LVSG and LRYGB. We undertook a systematic review and meta-analysis to compare 5-year weight loss outcomes of randomized controlled trials comparing LVSG to LRYGB.

Materials and Methods:

Searches of electronic databases (PubMed, Embase, CINAHL, Cochrane) were undertaken for randomized controlled trials describing weight loss outcomes in adults at 5 years postoperatively. Where sufficient data was available to undertake meta-analysis, the Hartung-Knapp-Sidik-Jonkman estimation method for random effects model was utilized. The review was registered with PROSPERO and reported following in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Results:

Five studies met the inclusion criteria totaling 1028 patients (LVSG=520, LRYGB=508). Moderate but comparable levels of bias were observed within studies. Statistically significant body mass index loss ranged from −11.37 kg/m2 (range: −6.3 to −15.7 kg/m2) in the LVSG group and −12.6 kg/m2 (range: −9.5 to −15.4 kg/m2) for LRYGB at 5 years (P<0.001). Systematic review suggested that LRYGB produced a greater weight loss expressed as percent excess weight and percent excess body mass index loss than LVSG: this was not corroborated in the meta-analysis.

Conclusions:

Five year weight loss outcomes suggest both LRYGB and LVSG are effective in achieving significant weight loss at 5 years postoperatively, however, differences in reporting parameters limit the ability to reliably compare the outcomes using statistical methods. Furthermore, results may be impacted by large dropout rates and per protocol analysis of the 2 largest included studies. Further long-term studies are required to contradict or validate the results of this meta-analysis.
Ethanol antagonizes P2X4 receptors in ventral tegmental area neurons
Authors: Rodriguez Larry , You Chang , Brodie Mark S. , Davies Daryl L.
Published: July 2020

P2X4 receptors are found throughout the central nervous system, and studies have shown that these purinergic receptors are important regulators of alcohol intake. The ventral tegmental area (VTA) is an important region for the rewarding and reinforcing properties of alcohol, but the role of P2X4 receptors in this region is unknown. Using both immunohistochemical and electrophysiological methods, we examined the interaction between P2X4 receptors and alcohol on VTA neurons. Incubation of brain slices containing the VTA for 2 h with siRNA targeting P2X4 receptors resulted in about a 25% reduction in P2X4 immunoreactivity in tyrosine hydroxylase positive VTA neurons. In electrophysiological experiments, ATP (0.5–3 mM) produced a reduction in the spontaneous firing rate, and ethanol significantly reduced this inhibition. Exposure to siP2X4 for 2 h via the recording micropipette resulted in a suppression of the response of VTA neurons to ATP, but no significant reduction in the ethanol inhibition of the ATP response was observed after this P2X4 downregulation. These results support the idea that VTA neurons are inhibited by ATP, ethanol antagonizes this inhibition, and the ethanol-sensitive component of ATP inhibition is mediated by P2X4 receptors. This interaction of ethanol with P2X4 receptors may be an important regulator of the rewarding effects of ethanol, making P2X4 receptors an intriguing target for the development of agents to treat alcohol use disorders.
Rapid progression of aortic stenosis after initiation of teriparatide treatment: a case report
Authors: Solomon Arie , Birkenfeld Shlomo
Published: July 2020

Introduction

Teriparatide, a recombinant formulation of endogenous PTH, is indicated for the treatment of osteoporosis in patients at high risk for fracture including postmenopausal women, men with primary or hypogonadal osteoporosis and patients with glucocorticoid-induced osteoporosis.

Case report

A 64-year-old Jewish osteoporotic woman initiated use of Teriparatide (FORTEOTM, 250 µg per 1 ml subcutaneously per day) in April 2018. Prior to therapy initiation, the patient has undergone eight echocardiograms with an aortic valve pressure gradient ranging between 29 and 39 mmHg, defined as mild aortic stenosis (AS), with no clear trend of progression. In two subsequent echo tests conducted 4 and 7 months after treatment initiation, there was a rapid progression of AS with gradient pressures of 55 and 58 mmHg, respectively.

Conclusion

Intermittent exposure to PTH analogues may be one of the causes of rapid progression of AS. Studies with sizeable populations are required to assess causal relationship between PTH analogues use and progression of AS.
A trade-off between resistance to infection and reproduction in primate evolution
Authors: Singh Sumnima , Thompson Jessica A. , Weis Sebastian , Sobral Daniel , Truglio Mauro , Yilmaz Bahtiyar , Rebelo Sofia , Cardoso Silvia , Gjini Erida , Nuñez Gabriel , Soares Miguel P.
Published: July 2020

Most mammals express a functionalGGTA1gene encoding the N-acetyllactosaminide α-1,3-galactosyltransferase enzyme, which synthesizes Galα1-3Galβ1-4GlcNAc (αGal) and are thus tolerant to this self-expressed glycan epitope. Old World primates including humans, however, carryGGTA1loss-of-function mutations and lack αGal. Presumably, fixation of such mutations was propelled by natural selection, favoring the emergence of αGal-specific immunity, which conferred resistance to αGal-expressing pathogens. Here we show that loss ofGgta1function in mice enhances resistance to bacterial sepsis, irrespectively of αGal-specific immunity. Rather, the absence of αGal from IgG-associated glycans increases IgG effector function, via a mechanism associated with enhanced IgG-Fc gamma receptor (FcγR) binding. The ensuing survival advantage against sepsis comes alongside a cost of earlier onset of reproductive senescence. Mathematical modeling of this trade-off shows that under conditions of high exposure to virulent pathogens, selective pressure can fixGGTA1loss-of-function mutations, as likely occurred during the evolution of primates towards humans.
A diffusion-like process enables expansion of advantaged gene mutations in human colonic epithelium
Authors: Olpe Cora , Khamis Doran , Chukanova Maria , Kemp Richard , Marks Kate , Tatton Cerys , Lindskog Cecilia , Skoufou-Papoutsaki Nefeli , Nicholson Anna , Brunton-Sim Roxanne , Malhotra Shalini , ten Hoopen Rogier , Stanley Rachel , Winton Doug , Morrissey Edward
Published: July 2020

Colorectal cancer is thought to arise when the mutational burden of the clonal population of stem cells within a colonic crypt exceeds a certain threshold. Therefore, quantification of the fixation and subsequent expansion of somatic mutations in histologically normal epithelium is key to understanding colorectal cancer initiation. Here, using immunohistochemistry, loss of the histone demethylase KDM6A in normal human colonic epithelium is visualised. Interpretation of the age-related behaviour of KDM6A-negative clones revealed significant competitive advantage in intra-crypt dynamics. Further, subsequent clonal expansion into multi-crypt patches was quantified to reveal a significant 5-fold increase in crypt fission rate. To accomodate the local accumulation of new crypts, the role of crypt fusion was considered. However, no compensatory increase in fusion rate was found. Instead, evidence for crypt diffusion is presented and proposed as a means of accommodating clonal expansions. The threshold fission rate at which diffusion fails to accommodate new crypts, and which may promote polyp growth, is defined.
Macromolecular refinement of X-ray and cryo-electron microscopy structures with Phenix / OPLS3e for improved structure and ligand quality
Authors: van Zundert Gydo C.P. , Moriarty Nigel W. , Sobolev Oleg V. , Adams Paul D. , Borrelli Kenneth W.
Published: July 2020

Accurate macromolecular structure refinement is of paramount importance in structure based drug discovery as it provides a gateway to using ligand binding free energy calculations and ligand docking techniques. When dealing with high-resolution data, a simple restraint model may be preferred when the data is able to guide atom parameters to an unambiguous location. However, at lower resolution, the additional information contained in a complex force field may aid in refinement by avoiding implausible structures permitted by the simpler restraints. With the advent of the resolution revolution in cryo-electron microscopy, low resolution refinement is common, and likewise increases the need for a reliable force field. Here we report on the incorporation of the OPLS3e force field with the VSGB2.1 solvation model in the widely used structure determination package Phenix. The implementation is versatile and can be used in both reciprocal and real space refinement, alleviating the need for manually creating accurate ligand restraint dictionaries in the form of CIF files. Our results show significantly improved structure quality at lower resolution for X-ray refinement with reduced ligand strain, while showing only a slight increase in Rfree. For real space refinement of cryo-EM based structures, we find comparable quality structures, goodness-of-fit and reduced ligand strain. In addition, we explicitly show how structure quality is related to the map-model cross correlation as a function of data weight, and how it can be an insightful tool for detecting both over- and underfitting, especially when coupled with ligand energies. Further, we have compiled a user-friendly start-to-end script for refining structures with Phenix/OPLS3e, which is available starting with the Schrödinger 2020-3 distribution.
“Single-nucleus RNA-seq2 reveals a functional crosstalk between liver zonation and ploidy”
Authors: Richter M. L. , Deligiannis I.K. , Danese A. , Lleshi E. , Coupland P. , Vallejos C.A. , Colome-Tatche M. , Martinez-Jimenez C.P.
Published: July 2020

Single-cell RNA-seq reveals the role of pathogenic cell populations in development and progression of chronic diseases. In order to expand our knowledge on cellular heterogeneity we have developed a single-nucleus RNA-seq2 method that allows deep characterization of nuclei isolated from frozen archived tissues. We have used this approach to characterize the transcriptional profile of individual hepatocytes with different levels of ploidy, and have discovered that gene expression in tetraploid mononucleated hepatocytes is conditioned by their position within the hepatic lobe. Our work has revealed a remarkable crosstalk between gene dosage and spatial distribution of hepatocytes.
STING Promotes Breast Cancer Cell Survival by an Inflammatory-Independent Nuclear Pathway Enhancing the DNA Damage Response
Authors: Cheradame Laura , Guerrera Ida Chiara , Gaston Julie , Schmitt Alain , Jung Vincent , Pouillard Marion , Radosevic-Robin Nina , Modesti Mauro , Judde Jean-Gabriel , Cairo Stefano , Goffin Vincent
Published: July 2020

STING (Stimulator of Interferon Genes) is a well-known endoplasmic reticulum-anchored adaptor of the innate immunity that triggers the expression of inflammatory cytokines in response to pathogen infection. In cancer cells, this pro-inflammatory pathway can be activated by genomic DNA damage potentiating antitumor immune responses. Here we report that STING promotes cancer cell survival and resistance to genotoxic treatment in a cell-autonomous manner. Mechanistically, we show that STING partly localizes at the inner nuclear membrane in various breast cancer cell lines and clinical tumor samples, and interacts with several proteins of the DNA damage response (DDR). STING overexpression enhances the amount of chromatin-bound DNA-dependent Protein Kinase (DNA-PK) complex, while STING silencing impairs DDR foci formation and DNA repair efficacy. Importantly, this function of STING is independent of its canonical pro-inflammatory pathway. This study highlights a previously unappreciated cell-autonomous tumor-promoting mechanism of STING that opposes its well-documented role in tumor immunosurveillance.

Graphical abstract
Sparse parallel independent component analysis and its application to identify linked genomic and gray matter alterations underlying working memory impairment in attention-deficit/hyperactivity disorder
Authors: Duan Kuaikuai , Chen Jiayu , Calhoun Vince D. , Jiang Wenhao , Rootes-Murdy Kelly , Schoenmacker Gido , Silva Rogers F. , Franke Barbara , Buitelaar Jan K. , Hoogman Martine , Oosterlaan Jaap , Hoekstra Pieter J , Heslenfeld Dirk , Hartman Catharina A , Sprooten Emma , Arias-Vasquez Alejandro , Turner Jessica A. , Liu Jingyu
Published: July 2020

Most psychiatric disorders are highly heritable and associated with altered brain structural and functional patterns. Data fusion analyses on brain imaging and genetics, one of which is parallel independent component analysis (pICA), enable the link of genomic factors to brain patterns. Due to the small to modest effect sizes of common genetic variants in psychiatric disorders, it is usually challenging to reliably separate disorder-related genetic factors from the rest of the genome with the typical size of clinical samples. To alleviate this problem, we propose sparse parallel independent component analysis (spICA) to leverage the sparsity of individual genomic sources. The sparsity is enforced by performing Hoyer projection on the estimated independent sources. Simulation results demonstrate that the proposed spICA yields improved detection of independent sources and imaging-genomic associations compared to pICA. We applied spICA to gray matter volume (GMV) and single nucleotide polymorphism (SNP) data of 341 unrelated adults, including 127 controls, 167 attention-deficit/hyperactivity disorder (ADHD) cases, and 47 unaffected siblings. We identified one SNP source significantly and positively associated with a GMV source in superior/middle frontal regions. This association was replicated with a smaller effect size in 317 adolescents from ADHD families, including 188 individuals with ADHD and 129 unaffected siblings. The association was found to be more significant in ADHD families than controls, and stronger in adults and older adolescents than younger ones. The identified GMV source in superior/middle frontal regions was not correlated with head motion parameters and its loadings (expression levels) were reduced in adolescent (but not adult) individuals with ADHD. This GMV source was associated with working memory deficits in both adult and adolescent individuals with ADHD. The identified SNP component highlights SNPs in genes encoding long non-coding RNAs and SNPs in genes MEF2C, CADM2, and CADPS2, which have known functions relevant for modulating neuronal substrates underlying high-level cognition in ADHD.
Impact of genetic susceptibility to multiple sclerosis on the T cell epigenome: proximal and distal effects
Authors: Roostaei Tina , Klein Hans-Ulrich , Felsky Daniel , Kivisäkk Pia , Connor Sarah M. , Kroshilina Alexandra , Yung Christina , Ma Yiyi , Kaskow Belinda J. , Shao Xiaorong , Rhead Brooke , Liu Jia , Patsopoulos Nikolaos , Barcellos Lisa F. , Weiner Howard L. , De Jager Philip L.
Published: July 2020

We establish a genome-wide map of DNA methylation quantitative trait locus (mQTL) effects in CD4+T cells isolated from multiple sclerosis (MS) patients. Utilizing this map in a colocalization analysis, we identify 19 loci where the same haplotype drives both MS susceptibility and local (cis-) DNA methylation. We also identify two distant (trans-) mQTL effects of MS susceptibility loci: (1) a chromosome 16 MS locus affectsPRDM8methylation (a chromosome 4 region not previously associated with MS susceptibility), and (2) the aggregate effect of MS variants in the major histocompatibility complex (MHC, chromosome 6) influences DNA methylation nearPRKCAon chromosome 17. Both effects are replicated in independent samples. Overall, we present a new methylome-wide mQTL resource for a key cell type in inflammatory disease research, uncover functional consequences of MS susceptibility variants, including the convergence of MHC risk alleles onto a new gene target involved in predisposition to MS.
Endophilin Recruitment via GPCR Interactions Enables Membrane Curvature Generation in the Absence of Anionic Lipids
Authors: Mondal Samsuzzoha , Powers Imania , Narayan Karthik , Botterbusch Samuel , Baumgart Tobias
Published: July 2020

The Bin/Amphiphysin/Rvs (BAR) family protein endophilin plays key roles in membrane curvature generation during endocytosis of cellular receptors. The Src homology 3 (SH3) domain of endophilin interacts with the proline rich third intracellular loop (TIL) of various G-protein coupled receptors (GPCRs). While electrostatic interactions between BAR domain and anionic membrane lipids have been considered to be the major driving force in curvature generation, it is unclear how the direct interaction between TIL and SH3 affects this function and its coupling with receptor internalization. Here we show that TIL mediated interactions alone not only recruit endophilin to the membrane but also facilitate curvature sorting and curvature generating behavior of endophilin. To demonstrate this, we designed model membranes with covalently lipid-conjugated TIL and lipids without net negative charge so that endophilin was recruited exclusively via SH3/TIL interactions. We find curvature generation and curvature sorting under those conditions. Furthermore, we show that TIL interacts electrostatically with membranes in the presence of anionic lipids and that this interaction can interfere with binding of SH3. Overall, our study suggests that an interplay between TIL, charged membranes, BAR domain, and SH3 domain mediate membrane curvature generation to regulate receptor endocytosis following receptor stimulation.
Multi-Drug-Resistance in Drug-Naive and Drug-Exposed Ovarian Cancer Cell Lines Responds Differently to Cell Culture Dimensionality
Authors: Koshkin Vasilij , de Oliveira Mariana Bleker , Peng Chun , Ailles Laurie E. , Liu Geoffrey , Covens Allan , Krylov Sergey N.
Published: July 2020

Does cell clustering influence intrinsic and acquired multi-drug resistance (MDR) differently? To address this question, we studied cultured monolayers (representing individual cells) and cultured spheroids (representing clusters) formed by drug-naïve (intrinsic MDR) and drug-exposed (acquired MDR) lines of ovarian cancer A2780 cells by cytometry of reaction rate constant (CRRC). MDR efflux was characterized by accurate and robust “cell number vs. MDR efflux rate constant (kMDR)” histograms. Both drug-naïve and drug-exposed monolayer cells presented unimodal histograms; the histogram of drug-exposed cells was shifted towards higher kMDR value suggesting greater MDR activity. Spheroids of drug-naïve cells presented a bimodal histogram indicating the presence of two subpopulations with different MDR activity. In contrast, spheroids of drug-exposed cells presented a unimodal histogram qualitatively similar to that of the monolayers of drug-exposed cells but with a moderate shift towards greater MDR activity. The observed greater effect of cell clustering on intrinsic than on acquired MDR can help guide the development of new therapeutic strategies targeting clusters of circulating tumor cells.
PARP1 inhibitors trigger innate immunity via PARP1 trapping-induced DNA damage response
Authors: Kim Chiho , Wang Xu-dong , Yu Yonghao
Published: July 2020

It is being increasingly appreciated that the immunomodulatory functions of PARP inhibitors (PARPi) underlie their clinical activities in variousBRCA-mutated tumors. PARPi possess both PARP1 inhibition and PARP1 trapping activities. The relative contribution of these two mechanisms toward PARPi-induced innate immune signaling, however, is poorly understood. We find that the presence of the PARP1 protein with uncompromised DNA-binding activities is required for PARPi-induced innate immune response. The activation of cGAS-STING signaling induced by various PARPi closely depends on their PARP1 trapping activities. Finally, we show that a small molecule PARP1 degrader blocks the enzymatic activity of PARP1 without eliciting PARP1 trapping or cGAS-STING activation. Our findings thus identify PARP1 trapping as a major contributor of the immunomodulatory functions of PARPi. Although PARPi-induced innate immunity is highly desirable in human malignancies, the ability of “non-trapping” PARP1 degraders to avoid the activation of innate immune response could be useful in non-oncological diseases.
Fungal mycelia and bacterial thiamine establish a mutualistic growth mechanism
Authors: Abeysinghe Gayan , Kuchira Momoka , Kudo Gamon , Masuo Shunsuke , Ninomiya Akihiro , Takahashi Kohei , Utada Andrew S. , Hagiwara Daisuke , Nomura Nobuhiko , Takaya Naoki , Obana Nozomu , Takeshita Norio
Published: July 2020

Physical spaces and nutrients are prerequisites to the survival of organisms while few interspecies mutual strategies are documented that satisfies them. Here we discovered a mutualistic mechanism between filamentous fungus and bacterium,Aspergillus nidulansandBacillus subtilis. The bacterial cells co-cultured with the fungus traveled along mycelia depending on their flagella and dispersed farther with the expansion of fungal colony, indicating that the fungal mycelia supply space for bacteria to migrate, disperse and proliferate. Transcriptomic, genetic, molecular mass and imaging analyses demonstrated that the bacteria reach the mycelial edge and supply thiamine to the growing hyphae, resulting in a promotion of hyphal growth. The thiamine transfer from bacteria to the thiamine non-auxotrophic fungus is directly demonstrated by stable isotope labeling. The simultaneous spatial and metabolic interactions demonstrated in this study, reveal a mutualism that facilitates the communicating fungal and bacterial species to obtain environmental niche and nutrient respectively.
Evaluation of fluorine-mediated intermolecular interactions in tetrafluorinated tetrahydroisoquinoline derivatives: synthesis and computational studies
Authors: Singla Labhini , Yadav Hare Ram , Roy Choudhury Angshuman
Published: July 2020

Intermolecular interactions involving the aromatic C—F group in the absence of other strong hydrogen bond acceptors is the theme of this article. Weak interactions involving fluorine are known to generate various supramolecular synthons, thereby altering the crystal structures of small organic molecules. It is demonstrated that the weak interactions involving organic fluorine play a major role in directing crystal packing of highly flexible organic molecules like diphenyl tetrahydroisoquinolines reported herein. The intramolecular C—H...F hydrogen bonds are found to be significant in controlling the molecular conformation in specific cases wheras the intermolecular interactions involving the C—F groups result in a wide range of supramolecular synthons involving C—H...F and C—F...F—C interactions. The interactions are studied computationally to provide insight into their energies and the topology of the interactions is studied using Atoms in Molecules. C—H...F—C interactions are found to be quite stabilizing in nature with the stabilization energy of −13.9 kcal mol−1.
Polyoxometalate clusters in minerals: review and complexity analysis
Authors: Krivovichev Sergey V.
Published: July 2020

Most research on polyoxometalates (POMs) has been devoted to synthetic compounds. However, recent mineralogical discoveries of POMs in mineral structures demonstrate their importance in geochemical systems. In total, 15 different types of POM nanoscale-size clusters in minerals are described herein, which occur in 42 different mineral species. The topological diversity of POM clusters in minerals is rather restricted compared to the multitude of moieties reported for synthetic compounds, but the lists of synthetic and natural POMs do not overlap completely. The metal–oxo clusters in the crystal structures of the vanarsite-group minerals ([As3+V4+
2V5+
10As5+
6O51]7−), bouazzerite and whitecapsite ([M
3+
3Fe7(AsO4)9O8–;n
(OH)
n
]), putnisite ([Cr3+
8(OH)16(CO3)8]8−), and ewingite ([(UO2)24(CO3)30O4(OH)12(H2O)8]32−) contain metal–oxo clusters that have no close chemical or topological analogues in synthetic chemistry. The interesting feature of the POM cluster topologies in minerals is the presence of unusual coordination of metal atoms enforced by the topological restraints imposed upon the cluster geometry (the cubic coordination of Fe3+ and Ti4+ ions in arsmirandite and lehmannite, respectively, and the trigonal prismatic coordination of Fe3+ in bouazzerite and whitecapsite). Complexity analysis indicates that ewingite and morrisonite are the first and the second most structurally complex minerals known so far. The formation of nanoscale clusters can be viewed as one of the leading mechanisms of generating structural complexity in both minerals and synthetic inorganic crystalline compounds. The discovery of POM minerals is one of the specific landmarks of descriptive mineralogy and mineralogical crystallography of our time.
Does corporate governance affect the performance of Islamic banks? New insight into Islamic countries
Authors: Aslam Ejaz , Haron Razali
Published: July 2020

Purpose

Corporate governance plays a significant role to overcome agency issues and develop the culture of transparency and openness. In this context, this paper aims to examine how corporate governance mechanisms affect the performance of Islamic banks (IBs).

Design/methodology/approach

Stepwise, two-step system generalize method of moment estimation technique is used in the analysis in which control variables are added into the model sequentially. This study used data on 129 IBs from 29 Islamic countries (Middle East, South Asia and Southeast Asia) during the period of 2008 to 2017.

Findings

The findings suggest that the audit committee (AUDC) andShariahboard (SB) have positive impact on the performance of IBs (return on assets and return on equity). However, board size and risk management committee have negative and significant effect on the performance of IBs. CEO duality and non-executive directors have mixed relationship with the performance of IBs. These results support the argument that IBs need to improve their financial performance through appropriate governance mechanism.

Research limitations/implications

The findings of the study added a new dimension to the governance research that could be a valuable source of knowledge for policymakers and regulators to improve the existing governance mechanism for better performance of IBs.

Originality/value

The study fills the gap in the literature by addressing the issue of corporate governance on performance of IBs across countries. Agency theory is discussed to explain the relationship between corporate governance mechanism and performance.
Cognitive attunement in the face of organizational plasticity
Authors: Secchi Davide
Published: July 2020

Purpose

The paper aims to use part of the distributed cognition literature to study how employees cope with organizational plasticity, in an attempt to identify the characteristics of cognitive plasticity.

Design/methodology/approach

Evidence is collected by designing and implementing an agent-based computational simulation model (the IOP 2.0) where employees have the option to use external resources and the social environment to perform tasks. As plasticity is more effective when change and uncertainty are high, the simulation features an increase in the difficulty and number of tasks to which employees need to cope.

Findings

Cooperation and sharing of competence and ability are key to cognitive plasticity. Being able to master the use of some resources, together with other employees’ competencies, make some achieve the most efficient task performance.

Practical implications

The findings suggest that under conditions of change and plasticity, human resource management (HRM) shall attempt to develop measures to support employees' cognitive skills necessary to cope with it, for example, mostly through diagnosis, training and facilitating on-the-job dialogue.

Originality/value

This is the first study that attempts a merger between organizational cognition and plasticity, and it is the first to match its results to HRM policy recommendations.
Correcting for endogeneity in hospitality and tourism research
Authors: Assaf A. George , Tsionas Mike
Published: July 2020

Purpose

This paper aims to foster a new discussion on endogeneity in hospitality and tourism research.

Design/methodology/approach

This paper elaborates on some of the common sources of endogeneity and the methods available to address them.

Findings

The authors present a variety of methods that can be used to mitigate the endogeneity problem. The authors provide simulation evidence regarding the risk of incorrectly selecting instrumental variables. The authors also provide several important practical recommendations for future research.

Research limitations/implications

There are other issues and methods of correcting for endogeneity, that is not covered in this paper. However, the paper focuses on issues and methods that can be generalized to most contexts.

Originality/value

The paper provides practical recommendations for more rigorous regression estimation.
The cost-effectiveness of insulin analogs and regular insulin for diabetes control: a case study in Iran
Authors: pakdaman Mohsen , akbari Raheleh , Dehghan Hamid reza , Asgharzadeh Asra , Namayandeh Mahdieh
Published: July 2020

Purpose

For years, traditional techniques have been used for diabetes treatment. There are two major types of insulin: insulin analogs and regular insulin. Insulin analogs are similar to regular insulin and lead to changes in pharmacokinetic and pharmacodynamic properties. The purpose of the present research was to determine the cost-effectiveness of insulin analogs versus regular insulin for diabetes control in Yazd Diabetes Center in 2017.

Design/methodology/approach

In this descriptive–analytical research, the cost-effectiveness index was used to compare insulin analogs and regular insulin (pen/vial) for treatment of diabetes. Data were analyzed in the TreeAge Software and a decision tree was constructed. A 10% discount rate was used for ICER sensitivity analysis. Cost-effectiveness was examined from a provider's perspective.

Findings

QALY was calculated to be 0.2 for diabetic patients using insulin analogs and 0.05 for those using regular insulin. The average cost was $3.228 for analog users and $1.826 for regular insulin users. An ICER of $0.093506/QALY was obtained. The present findings suggest that insulin analogs are more cost-effective than regular insulin.

Originality/value

This study was conducted using a cost-effectiveness analysis to evaluate insulin analogs versus regular insulin in controlling diabetes. The results of study are helpful to the government to allocate more resources to apply the cost-effective method of the treatment and to protect patients with diabetes from the high cost of treatment.
An investigation of impact-sliding behavior and fretting wear of tubes against different supports in steam generators
Authors: Guo Kai , Han Zhongli , Wang Yipeng , Wang Yang , Tan Wei
Published: July 2020

Purpose

The purpose of this study is to reveal the interaction behavior between tubes and supports in steam generators and study the fretting wear of tubes in different load conditions.

Design/methodology/approach

The fretting wear tests were conducted to investigate the fretting wear behavior of the tubes against three kinds of supports: the drilled circular holes (DCH), anti-vibration bars (AVBs) and trefoil orifice holes (TOH), which are widely used supports in nuclear steam generators. In this paper, the comparison of the interaction characteristic with different impact factors was established such as clearances and loads in the three kinds of supports. The fretting wear volume and scars were analyzed by a scanning electron microscope and 3D profiler.

Findings

The results show that impact can play a more important role in the DCH and TOH supports than that in AVBs. The normal work rate can be underestimated in the DCH and TOH supports.

Originality/value

The results of this study can be reference of fretting wear calculation in the design of steam generators with different kinds of supports and can be guidance in the maintenance of steam generators.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2019-0513/
Mandatory audit firm rotation: a critical composition of practitioner views from an emerging economy
Authors: Harber Michael , Maroun Warren
Published: July 2020

Purpose

This study aims to address an acknowledged gap in the literature for the analysis of experienced practitioner views on the effects and implications of mandatory audit firm rotation (MAFR).

Design/methodology/approach

Using an exploratory and sequential design, data was collected from South African regulatory policy documents, organisational comment letters and semi-structured interviews of practitioners. These findings informed a field survey, administered to auditors, investors, chief financial officers (CFOs) and audit committee members of Johannesburg Stock Exchange (JSE) listed companies.

Findings

Practitioners expressed considerable pushback against the potential efficacy of MAFR to improve audit quality due to various “switching costs”, notably the loss of client-specific knowledge and expertise upon rotation. In addition, the cost and disruption to both the client and audit firm are considered significant and unnecessary, compared to audit partner rotation. The audit industry may suffer reduced profitability and increased strain on partners, leading to a decline in the appeal of the profession as a career of choice. This is likely to have negative implications for audit industry diversity objectives. Furthermore, the industry may become more supplier-concentrated amongst the Big 4 firms.

Practical implications

The findings have policy implications for regulators deciding whether to adopt the regulation, as well as guiding the design of policies and procedures to mitigate the negative effects of adoption.

Originality/value

The participants are experienced with diverse roles concerning the use, preparation and audit of financial statements of large exchange-listed multinational companies, as well as engagement in the auditor appointment process. The extant literature presents mixed results on the link between MAFR and audit quality, with most studies relying on archival and experimental designs. These have a limited ability to identify and critique the potential’s witching costs and unintended consequences of the regulation. Experienced participants responsible for decision-making within the audit, audit oversight and auditor appointment process, are best suited to provide perspective on these effects, contrasted against the audit regulator’s position.
Role of conspicuous value in luxury purchase intention
Authors: Jain Sheetal
Published: July 2020

Purpose

Generation Y consumers are the key drivers for luxury market growth in the future. Yet, very few studies have been performed to understand Gen Y consumers' luxury consumption behavior, mainly in context of emerging markets like India. The main objectives of this study are first, to develop a conceptual framework which integrates the role of key variables that influence Gen Y consumers' purchase intention for luxury goods. Second, to analyze the mediating effect of attitude and subjective norm on the relationship between conspicuous value and luxury purchase intention.

Design/methodology/approach

Data were collected through structured questionnaires from a sample of 215 Gen Y luxury fashion consumers in India. Collected data were analyzed through confirmatory factor analysis (CFA) and Hayes Process macro in SPSS.

Findings

The findings revealed that attitude and subjective norm partially mediated the relationship between conspicuous value and luxury purchase intention. The findings also demonstrated that mediation effect significantly differs between consumers with low and high need for status as well as consumers with low and high need for uniqueness.

Originality/value

This is the first study performed to understand the mediating and moderating effect of various contextual variables (namely, attitude, subjective norm, uniqueness value and status value) on the association between conspicuous value and luxury purchase intention. This study will have important implications for both academicians and practitioners.
Emotional intelligence as an antidote to the negative implications of perceived managerial supplication: a sectorial comparison
Authors: Meisler Galit
Published: July 2020

Purpose

This study investigated whether managers' nonaggressive political behavior can result in negative emotional and attitudinal outcomes such as aggressive behavior and the role of emotional intelligence (EI) in this context. The authors explored a moderated mediation model in which perceived managerial supplication elicited hostility that increased turnover intentions and the emotional abilities included in EI acted as antidotes to these outcomes.

Design/methodology/approach

The authors tested the moderated mediation model using two large samples, one from the public sector and the other from the private sector, providing a cross-sectorial comparison. The authors collected the data for this study in three waves.

Findings

The authors’ findings revealed that the model fit the public sector alone. Moreover, others' emotion appraisal was the only aspect of EI that moderated the hostility and turnover intentions of public servants.

Practical implications

Interventions aimed at increasing the EI level of public servants can be a powerful tool for reducing their hostility and turnover intentions. However, these interventions must focus on all four aspects of EI , particularly others' emotion appraisal.

Originality/value

Managers' nonaggressive political behavior can result in negative emotional and attitudinal outcomes such as aggressive behavior. However, EI reduces these negative outcomes among public servants.
Blockchain technology-enabled supply chain systems and supply chain performance: a resource-based view
Authors: Nandi Madhavi Latha , Nandi Santosh , Moya Hiram , Kaynak Hale
Published: July 2020

Purpose

Using the resource-based theoretical view of the firm, this paper aims to explore how firms’ efforts to integrate blockchain technology (BCT) into their supply chain systems and activities enable certain supply chain capabilities and, consequently, improve their supply chain performance.

Design/methodology/approach

Using an abductive research approach, a qualitative content analysis was conducted on 126 cases of firms attempting to implement a blockchain technology-enabled supply chain system (BCTeSCS). These firms spanning across multiple industries were identified using the Nexis Uni database.

Findings

Findings reveal that present BCTeSCS efforts are more-oriented toward improving operational-level capabilities (information sharing and coordination capabilities) than strategic-level capabilities (integration and collaboration capabilities). These operational and strategic-level capabilities alongside BCTeSCS deliver several supply chains performance outcomes such as quality compliance and improvement, process improvement, flexibility, reduced cost and reduced process time. However, outcomes may vary by industry type based on their uncertainties.

Research limitations/implications

Given the nascent state of BCT, accessibility to primary data about ongoing BCTeSCS efforts is limited. The presented framework is based on 126 cases of secondary information. Within this constraint, the paper finds scope to future empirical research by proposing a resource-based framework of BCTeSCS and related propositions.

Practical implications

The results and discussion of this study serve as useful guidance for practitioners involved in BCTeSCS integrations.

Social implications

The paper creates a BCTeSCS scenario for stakeholders to assume its potential socio-economic and socio-environmental pressures.

Originality/value

This paper is one of the initial attempts to examine BCTeSCS efforts across multiple industries, and thus, promises a broad future research scope.
Scale‐dependent changes in tree diversity over more than a century in eastern Canada: Landscape diversification and regional homogenization
Authors: Danneyrolles Victor , Vellend Mark , Dupuis Sébastien , Boucher Yan , Laflamme Jason , Bergeron Yves , Fortin Gabriel , Leroyer Marie , de Römer André , Terrail Raphaële , Arseneault Dominique
Published: July 2020

A better understanding of how disturbance impacts tree diversity at different scales is essential for our ability to conserve and manage forest ecosystems in the context of global changes. Here we test the impacts of land use‐related disturbances on tree diversity since the 19th century across a broad region (>150,000 km2) of northern temperate forests in eastern Canada.

We used a large and unique dataset of early land surveys conducted during the 19th century (>130,000 species lists), along with modern forest inventories (>80,000 plots), to analyse long‐term changes in taxonomic and functional tree diversity at several scales (grid cell resolutions ranging from 12.5 to 1,600 km2; we refer to one grid cell as a ‘landscape’).

Our results show that land use‐related disturbances have led simultaneously to (a) increased diversity within landscapes and a (b) homogenization at the regional scale (i.e. decreased composition dissimilarity among landscapes). These trends were found for both taxonomic diversity and functional diversity, with temporal changes more pronounced for taxonomic than functional diversity. We also found an increase over time in the strength of correlations between environmental variables and diversity both within and among landscapes.

Synthesis. Our results support the idea that human‐induced impacts on biodiversity are strongly scale‐dependent and not necessarily associated with biodiversity loss. This highlights possible ways that human‐driven changes in tree diversity might impact forest resistance and resilience to future global changes.