bluuebunny/crossref_metadata_2025 huggingface dataset:
Validation of a Novel Fecal Incontinence Scale
Authors: de la Portilla Fernando , Ramallo Irene , Maestre Maria V. , Roig José V. , Devesa Manuel , Padillo Francisco J.
Published: April 2020

Objective:

The development and validation of a new version of the fecal incontinence (FI) scale “Rapid Assessment Fecal Incontinence Score” (RAFIS) incorporating domains for severity, type of stool loss, and global perception of the effect of incontinence on quality of life (QoL).

Background:

FI negatively impacts on QoL. Currently used incontinence questionnaires have outstanding limitations on the global assessment of the impact of the disease on QoL that patients perceive. We developed a new version of RAFIS with a more complete questionnaire.

Materials and Methods:

A 3-phase study was performed to evaluate the applicability and reliability of our questionnaire as a tool for assessing FI. Our score was completed by 98 patients (78 women; mean age: 57±13 y) who presented with FI and who were referred from 4 colorectal surgery centers. The RAFIS was assessed for internal consistency, test-retest reliability, and sensitivity to change. A multivariate analysis was performed. Comparisons were made with the Wexner Cleveland Clinic Incontinence Score and the Fecal Incontinence Quality of Life Scale.

Results:

The RAFIS showed good internal consistency and test-retest reliability, differentiating the severity of incontinence but not the etiology. There was a moderate-high correlation between the new scale and the reference scales. Sensitivity to change, compared with the Wexner Score, was moderate. Comparison with established QoL instruments showed a moderate negative correlation. Logistic regression of the RAFIS discriminated between mild and moderate-severe impact on QoL. No correlation was detected with the new score to the presence of an anal sphincter defect or sphincter hypotonia.

Conclusion:

The RAFIS scale is easy to administer and compares well with other validated incontinence instruments.
Esophagogastric Junction Outflow Obstruction
Authors: Csucska Máté , Masuda Takahiro , Bremner Ross M. , Mittal Sumeet K.
Published: April 2020

Goals:

The authors aimed to compare preperistaltic distal esophageal pressure in patients with esophagogastric junction outflow obstruction (EGJOO) with and without reported dysphagia.

Background:

Manometric EGJOO is characterized by elevated integral relaxation pressure (>15 mm Hg) without achalasia. The nomenclature inherently implies that it should be associated with impaired food bolus transit and should theoretically present clinically as dysphagia.

Study:

The authors queried an esophageal functional test database to identify patients diagnosed with EGJOO. They excluded patients who presented with ≥2 swallows with abnormal (ie, weak, failed or hypercontractile) esophageal body motility. To elucidate differences in manometric findings, the authors formed 2 cohorts of patients on the basis of a standard esophageal symptom questionnaire: those without dysphagia and those with severe or very severe dysphagia. All studies were reanalyzed to determine the distal esophageal pressure before each peristaltic wave (ie, the preperistaltic pressure) for individual swallows. The Mann-Whitney U test was used to compare categorical variables between groups. The level of significance was set to P<0.05.

Results:

In total, 149 patients were diagnosed with EGJOO during the study period. Of these, 42 patients with ≥9 (out of 10) peristalsis (20 without dysphagia and 22 with severe/very severe dysphagia) formed the study cohorts. Patients with severe dysphagia had significantly higher median preperistaltic pressures in the distal esophagus. Preperistaltic pressure measurements showed better sensitivity and specificity for dysphagia than integral relaxation pressure.

Conclusions:

Elevated preperistaltic pressure is noted in symptomatic EGJOO patients. Inclusion of preperistaltic pressure in the diagnostic criteria for EGJOO may increase the clinical relevance of manometric classification.
A Review of Sleep Architecture and Sleep Changes During Pregnancy
Authors: Sweet Lauren , Arjyal Sushrusha , Kuller Jeffrey A. , Dotters-Katz Sarah
Published: April 2020

Importance

Poor sleep is widely recognized as a common complaint in pregnancy, and yet there are incomplete data on the exact nature of these complaints, what their implications for fetal and maternal health are, and how to best recognize and address these significant health issues.

Objectives

The purpose of this article is to review the current literature on the changes in objectively measured sleep parameters that occur during pregnancy, identify any possible trends, and discuss current implications for obstetric outcomes and treatments.

Evidence Acquisition

PubMed NCBI and Google Scholars database were searched for a variety of sleep-related terms, and articles were selected based on relevance to the topic and method of sleep pattern monitoring.

Results

Poor sleep is ubiquitous during pregnancy, and the relatively few studies evaluating the issue using objective polysomnography have small sample sizes. However, data suggests sleep architecture changes begin as early as the first trimester, and there is evidence that primigravid sleep structure never returns to prepregnancy levels after birth. In addition, cesarean delivery frequency, early labor, labor length, depression, gestational hypertension, and gestational diabetes all appear to be influenced by sleep changes. Current treatments are based on nonpregnant populations and may not be appropriate for the gravid patient.

Conclusions and Relevance

Disordered sleep is a more widespread and serious issue than most women are aware, and there are numerous obstetric and general health implications to cause clinician concern. More research is needed on both electroencephalography architecture changes and treatment options.

Target Audience

Obstetricians and gynecologists, family physicians.

Learning Objectives

After participating in this activity, the provider should be better able to outline current literature regarding trimester-specific sleep architecture changes; describe the maternal and obstetric outcomes that poor sleep may contribute too; and identify current therapies for poor sleep during pregnancy.
Preoperative Nasal Swab Culture: Is It Beneficial in Preventing Postoperative Infection in Complicated Septorhinoplasty?
Authors: Moon Kyung-Chul , Jung Jae-Eun , Dhong Eun-Sang , Jeong Seong-Ho , Han Seung-Kyu
Published: April 2020

Background:

Surgical-site infection following complicated septorhinoplasty may result in serious complications. Therefore, efforts to prevent surgical-site infections after complicated septorhinoplasty are important. The purpose of this study was to analyze the microbiological profile of preoperative nasal swab cultures and to evaluate the effect of antibiotic prophylaxis and topical antibiotic decolonization according to the antibiotic sensitivity results of surgical-site infections in complicated septorhinoplasty.

Methods:

This 10-year cohort study included the data on 437 consecutive patients who underwent complicated septorhinoplasty. The patients were categorized into three cohorts based on the time of preoperative nasal swab culture collection. Patients in cohort 1 did not undergo nasal swab cultures and received empirical antibiotics. Patients in cohort 2 underwent only one preoperative nasal swab culture and received microorganism-sensitive antibiotics. Patients in cohort 3 underwent repeated nasal swab cultures. The antibiotics were changed when microorganisms resistant to the empirical antibiotics were isolated. Microbiological data and the rates of surgical-site infection and inflammation were compared among the three cohorts.

Results:

Methicillin-sensitive Staphylococcus aureus was the most commonly isolated microorganism. In cohort 1, two (5 percent) and two (5 percent) patients experienced surgical-site infections and inflammation, respectively. In cohort 2, two (3 percent) and three (4 percent) patients experienced surgical-site infections and inflammation, respectively. In cohort 3, one (0.3 percent) and one (0.3 percent) patient experienced surgical-site infection and inflammation, respectively.

Conclusion:

The present study demonstrated that preoperative screening using repeated nasal swab cultures, followed by appropriate antibiotic prophylaxis and topical antibiotic decolonization, may reduce surgical-site infection in complicated septorhinoplasty.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, III.
Conservative Management of de Quervain Stenosing Tenosynovitis: Review and Presentation of Treatment Algorithm
Authors: Abi-Rafeh Jad , Kazan Roy , Safran Tyler , Thibaudeau Stephanie
Published: April 2020

Background:

Nonsurgical management of de Quervain disease relies mainly on the use of oral nonsteroidal antiinflammatory drug administration, splint therapy, and corticosteroid injections. Although the latter is most effective, with documented success rates of 61 to 83 percent, there exists no clear consensus pertaining to conservative treatment protocols conferring the best outcomes. This article reports on all present conservative treatment modalities in use for the management of de Quervain disease and highlights specific treatment- and patient-related factors associated with the best outcomes.

Methods:

A systematic search was performed using the PubMed database using appropriate search terms; two independent reviewers evaluated retrieved articles using strict inclusion and exclusion criteria.

Results:

A total of 66 articles met the inclusion criteria for review, consisting of 22 articles reporting on outcomes following a single conservative treatment modality, eight articles reporting on combined treatment approaches, 13 articles directly comparing different conservative treatment regimens, and 23 case reports.

Conclusions:

A multimodal approach using splint therapy and corticosteroid injections appears to be more beneficial than either used in isolation. Although there exists some evidence showing that multipoint injection techniques and multiple injections before surgical referral may provide benefit over a single point injection technique and a single injection before surgery, corticosteroid use is not benign and should thus be performed with caution. Ultrasound was proven valuable in the visualization of an intercompartmental septum, and ultrasound-guided injections were shown to both be more accurate and confer better outcomes. Several prior and concurrent medical conditions may affect conservative treatment outcome. A Level I to II evidence-based treatment protocol is recommended for the optimal nonsurgical management of de Quervain disease.
The Attachments of the Breast to the Chest Wall: A Dissection Study
Authors: Gaskin Kathryn M. , Peoples Gregory E. , McGhee Deirdre E.
Published: April 2020

Background:

The anatomical descriptions of the attachments of the female breast to the chest wall vary in their structure, location, and terminology within the published literature.

Methods:

A dissection study of the attachments of the breast to the chest wall was conducted on 18 female embalmed breasts in the coronal (n = 15) and sagittal planes (n = 3).

Results:

Perimeter, posterior wall, and horizontal septum attachments were observed. The perimeter along its entire length was attached to the chest wall. Regional and anatomical variation was observed in this structure and location. Sharp dissection was required to remove it from the chest wall, in contrast to the blunt dissection required to remove the posterior wall and horizontal septum attachments.

Conclusions:

The breast attaches to the chest wall along its entire perimeter, posterior wall, and horizontal septum, with the perimeter functioning as the primary anchor of the breast to the chest wall. The structure of the perimeter attachment is both periosteal and fascial and requires sharp dissection to remove it from the chest wall. The fascial structures of the posterior wall and horizontal septum require blunt dissection only. The structure of the perimeter has regional variation, and its location on the chest wall has anatomical variation. Detailed anatomical descriptions and illustrations are supported by photographic evidence of cadaver dissections in two planes. Clinical and anatomical terminology are linked, with clinical implications for medical anatomy education, breast modeling, and breast surgery.
Complex Linkage Disequilibrium Effects in HLA-DPB1 Expression and Molecular Mismatch Analyses of Transplantation Outcomes
Authors: Shieh Mengkai , Hayeck Tristan J. , Dinh Anh , Duke Jamie L. , Chitnis Nilesh , Mosbruger Timothy , Morlen Ryan P. , Ferriola Deborah , Kneib Carolina , Hu Taishan , Huang Yanping , Monos Dimitri S.
Published: April 2020

Background.

HLA molecular mismatch (MM) is a risk factor for de novo donor-specific antibody (dnDSA) development in solid organ transplantation. HLA expression differences have also been associated with adverse outcomes in hematopoietic cell transplantation. We sought to study both MM and expression in assessing dnDSA risk.

Methods.

One hundred three HLA-DP-mismatched solid organ transplantation pairs were retrospectively analyzed. MM was computed using amino acids (aa), eplets, and, supplementarily, Grantham/Epstein scores. DPB1 alleles were classified as rs9277534-A (low-expression) or rs9277534-G (high-expression) linked. To determine the associations between risk factors and dnDSA, logistic regression, linkage disequilibrium (LD), and population-based analyses were performed.

Results.

A high-risk AA:GX (recipient:donor) expression combination (X = A or G) demonstrated strong association with HLA-DP dnDSA (P = 0.001). MM was also associated with HLA-DP dnDSA when evaluated by itself (eplet P = 0.007, aa P = 0.003, Grantham P = 0.005, Epstein P = 0.004). When attempting to determine the relative individual effects of the risk factors in multivariable analysis, only AA:GX expression status retained a strong association (relative risk = 18.6, P = 0.007 with eplet; relative risk = 15.8, P = 0.02 with aa), while MM was no longer significant (eplet P = 0.56, aa P = 0.51). Importantly, these risk factors are correlated, due to LD between the expression-tagging single-nucleotide polymorphism and polymorphisms along HLA-DPB1.

Conclusions.

The MM and expression risk factors each appear to be strong predictors of HLA-DP dnDSA and to possess clinical utility; however, these two risk factors are closely correlated. These metrics may represent distinct ways of characterizing a common overlapping dnDSA risk profile, but they are not independent. Further, we demonstrate the importance and detailed implications of LD effects in dnDSA risk assessment and possibly transplantation overall.
Enhanced recovery after surgery (ERAS) protocols is extremely beneficial in liver surgeries – A metaanalysis
Authors: Vasavada Bhavin , Patel Hardik
Published: April 2020

BACKGROUND

Enhanced recovery after surgery (ERAS) programs aim to improve postoperative outcomes.. This metaanalysis aims to evaluate the impact of ERAS programmes on outcomes following liver surgeries.

METHODS

EMBASE, MEDLINE, PubMed and the Cochrane Database were searched for studies comparing outcomes in patients undergoing liver surgery utilizing ERAS principles with those patients receiving conventional care. The primary outcome was occurrence of 30 day morbidity and mortality. Secondary outcomes included length of stay, functional recovery, readmission rates,time to pass flatus,blood loss and hospital costs.

RESULTS

Ten articles were included in the metaanalysis. 30 days morbidity and mortality was significantly less in ERAS group.Hospital stay, time to pass flatus, time to complete recovery and hospital costs were also significantly reduced due to ERAS protocols. Blood loss and readmission rates were also significantly less in ERAS group.

CONCLUSIONS

The adoption of ERAS protocols significantly reduced morbidity, mortality hospital stay, readmission rates, time to recovery, hospital costs, time to pass flatus, blood loss and readmission rates.
GABA AND GLUTAMATE CHANGES IN PEDIATRIC MIGRAINE
Authors: Bell Tiffany , Stokoe Mehak , Khaira Akashroop , Webb Megan , Noel Melanie , Amoozegar Farnaz , Harris Ashley D
Published: April 2020

Despite migraine being one of the top five most prevalent childhood diseases, a lack of knowledge about pediatric migraine limits effective treatment strategies; standard adult pharmaceutical therapies are less effective in children and can carry undesirable side-effects. Non-pharmacological therapies have shown some success in adults; however, to appropriately apply these in children we need to understand pediatric migraine’s underlying biology. One theory is that migraine results from an imbalance in cortical excitability. Magnetic resonance spectroscopy (MRS) studies show changes in GABA and glutamate levels (the primary inhibitory and excitatory neurotransmitters in the brain, respectively) in multiple brain regions. Although there is indirect evidence of abnormal excitability in pediatric migraine, GABA and glutamate levels have yet to be assessed.

The purpose of this study was to measure levels of GABA and glutamate in the thalamus, sensorimotor cortex and visual cortex of children with migraine using MRS. We found that children with migraine and aura had significantly lower glutamate levels in the visual cortex as compared to control children, opposite to results seen in adults. Additionally, we found significant correlations between metabolite levels and migraine characteristics; higher GABA levels were associated with a higher migraine burden. We also found that higher glutamate in the thalamus and higher GABA/Glx ratios in the sensorimotor cortex were associated with duration since diagnosis, i.e., having migraines longer. Lower GABA levels in the sensorimotor cortex were associated with being closer to their next migraine attack. Together this indicates that GABA and glutamate disturbances occur early in migraine pathophysiology and emphasizes that evidence from adults with migraine cannot be immediately translated to paediatric sufferers. This highlights the need for further mechanistic studies of migraine in children, to aid in the development of more effective treatments.
Dexmedetomidine mediates microRNA-185 to suppress ovarian cancer growth via inhibiting the SOX9/Wnt/β-catenin signaling pathway
Authors: Tian Hang , Hou Lei , Xiong Yumei , Cheng Qiuju
Published: April 2020

Objective: Cervical cancer (CC) is a serious health problem, causing heavy burden each year worldwide. Long non-coding RNA (lncRNA) is implicated in CC progression. This study aims to clarify the underlying mechanism of lncRNA HAND2 AS1 in CC cellular process. Method: LncRNA expression in CC tissues and adjacent tissues was analyzed via Gene Expression Omnibus microarray. The levels of HAND2-AS1, microRNA (miR)-21 and ALEX1 in 54 cases of CC tissues, adjacent tissues, CC cell lines and normal breast cells were detected. The malignant biological behaviors of CC cells were detected after overexpressing HAND2-A S1 or inhibiting miR-21 expression. Bioinformatics analysis, luciferase reporter assay and RNA-pull down assay were performed to verify the relationship among HAND2-AS1, miR-21 and ALEX1. The effects of HAND2-AS1 on CC cell growth in vivo were verified by nude mice transplantation experiment. Results: HAND2-AS1 was lowly expressed in CC tissues and cells, and HAND2-AS1 functioned as a competitive endogenous RNA of miR-21 and enhanced ALEX1 expression and downregulated JAK1/STAT3 pathway to inhibit malignant biological behavior of CC cells. Overexpression of HAND2-AS1 or silencing of miR-21 can inhibit the malignant biological behavior of CC cells. Moreover, overexpression of HAND2-AS1 can inhibit the growth of CC cells in vivo. Conclusion: Our data supported that lncRNA HAND2-AS1 promoted ALEX1 expression through competitively binding to miR-21, thereby inhibiting the proliferation and epithelial-mesenchymal transformation and promoting apoptosis of CC cells. Keyword: Cervical cancer; LncRNA HAND2-AS1; microRNA-21; Competitive endogenous RNA; ALEX1; JAK1/STAT3 pathway
Expression from DIF1-motif promoters of hetR and patS is dependent on HetZ and modulated by PatU3 during heterocyst differentiation
Authors: Du Yaru , Zhang He , Wang Hong , Wang Shuai , Lei Qiqin , Li Chao , Kong Renqiu , Xu Xudong
Published: April 2020

HetR and PatS/PatX-derived peptides are the activator and diffusible inhibitor for cell differentiation and patterning in heterocyst-forming cyanobacteria. HetR regulates target genes via HetR-recognition sites. However, some genes (such as patS / patX ) upregulated at the early stage of heterocyst differentiation possess DIF1 (or DIF + ) motif (TCCGGA) promoters rather than HetR-recognition sites; hetR possesses both regulatory elements. How HetR controls heterocyst-specific expression from DIF1 motif promoters remains to be answered. This study presents evidence that the expression from DIF1 motif promoters of hetR , patS and patX is more directly dependent on hetZ , a gene regulated by HetR via a HetR-recognition site. The HetR-binding site upstream of hetR is not required for the autoregulation. PatU3 (3′ portion of PatU) that interacts with HetZ may modulate HetZ-dependent gene expression. These findings contribute to understanding of the mutual regulation of hetR , hetZ-patU and patS / patX in a large group of multicellular cyanobacteria.
Prevalence and antibiotic resistance of  spp. in South Punjab-Pakistan
Authors: Ismail Tariq , Qamar Aftab ,   Taiq Ismail
Published: April 2020

Present study aimed at investigating the magnitude of the prevalence and antibiotic resistance among four Salmonella spp. i.e. S. typhi , S. paratyphi A, S. paratyphi B and S. typhimurium, present in raw milk and environment samples from five districts of southern part of the Province of Punjab in Pakistan i.e. Multan , Bahawalpur, Lodhran, Dera Ghazi Khan and Muzaffargarh. A total of 3000 raw milk and environment samples were collected from these sites and analyzed for detection and confirmation of Salmonella spp. Extent of antibiotic resistance was also determined and classified as resistant, intermediate and susceptible. S. typhimurium was found to be more prevalent in Multan region as compared to other districts. Increased emergence of antibacterial resistance among Salmonella spp. from raw milk samples was noted. Amongst 13 tested antibiotics, chloramphenicol and ofloxacin were found to be the most susceptible against Salmonella spp. Present study suggested serious interventions by relevant government agencies to ensure best practices in animal husbandry at farm level and sagacious use of antibiotics for the containment of antimicrobial resistance in Salmonella spp.
VIBRIO CHOLERAE ADAPTS TO SESSILE AND MOTILE LIFESTYLES BY CYCLIC DI-GMP REGULATION OF CELL SHAPE
Authors: Fernandez Nicolas L. , Nhu Nguyen T. Q. , Hsueh Brian Y. , Franklin Joshua L. , Dufour Yann S. , Waters Christopher M.
Published: April 2020

The cell morphology of rod-shaped bacteria is determined by the rigid net of peptidoglycan forming the cell wall. WhileV. choleraegrows into a curved shape under most conditions, straight rods have been observed. However, the signals and regulatory pathways controlling cell shape transitions inV. choleraeand the benefits of switching between rod and curved shape have not been determined. We demonstrate that cell shape inV. choleraeis regulated by the bacterial second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) by repressing expression ofcrvA, a gene encoding an intermediate filament-like protein necessary for curvature formation inV. cholerae.This regulation is mediated by the transcriptional cascade that also induces production of biofilm matrix components, indicating that cell shape is coregulated withV. cholerae’s induction of sessility. Wild-typeV. choleraecells adhering to a surface lose their characteristic curved shape to become as straight as cells lackingcrvAwhile genetically engineering cells to maintain high curvature reduced microcolony formation and biofilm density. Conversely, straightV. choleraemutants have reduced speed when swimming using flagellar motility in liquid. Our results demonstrate regulation of cell shape in bacteria is a mechanism to increase fitness in planktonic or biofilm lifestyles.
TANGO1 membrane helices create a lipid diffusion barrier at curved membranes
Authors: Raote Ishier , Ernst Andreas M. , Campelo Felix , Rothman James E. , Pincet Frederic , Malhotra Vivek
Published: April 2020

We have previously shown TANGO1 organises membranes at the interface of the endoplasmic reticulum (ER) and ERGIC/Golgi (Raote et al., 2018). TANGO1 corrals retrograde membranes at ER exit sites to create an export conduit. Here the retrograde membrane is, in itself, an anterograde carrier. This mode of forward transport necessitates a mechanism to prevent membrane mixing between ER and the retrograde membrane. TANGO1 has an unusual membrane helix organisation, composed of one membrane-spanning helix (TM) and another that penetrates the inner leaflet (IM). We have reconstituted these membrane helices in model membranes and shown that TM and IM together reduce the flow of lipids at a region of defined shape. We have also shown that the helices align TANGO1 around an ER exit site. We suggest this is a mechanism to prevent membrane mixing during TANGO1-mediated transfer of bulky secretory cargos from the ER to the ERGIC/Golgi via a tunnel.
A design of resonant inelastic X-ray scattering (RIXS) spectrometer for spatial- and time-resolved spectroscopy
Authors: Chuang Yi-De , Feng Xuefei , Glans-Suzuki Per-Anders , Yang Wanli , Padmore Howard , Guo Jinghua
Published: April 2020

The optical design of a Hettrick–Underwood-style soft X-ray spectrometer with Wolter type 1 mirrors is presented. The spectrometer with a nominal length of 3.1 m can achieve a high resolving power (resolving power higher than 10000) in the soft X-ray regime when a small source beam (<3 µm in the grating dispersion direction) and small pixel detector (5 µm effective pixel size) are used. Adding Wolter mirrors to the spectrometer before its dispersive elements can realize the spatial imaging capability, which finds applications in the spectroscopic studies of spatially dependent electronic structures in tandem catalysts, heterostructures, etc. In the pump–probe experiments where the pump beam perturbs the materials followed by the time-delayed probe beam to reveal the transient evolution of electronic structures, the imaging capability of the Wolter mirrors can offer the pixel-equivalent femtosecond time delay between the pump and probe beams when their wavefronts are not collinear. In combination with some special sample handing systems, such as liquid jets and droplets, the imaging capability can also be used to study the time-dependent electronic structure of chemical transformation spanning multiple time domains from microseconds to nanoseconds. The proposed Wolter mirrors can also be adopted to the existing soft X-ray spectrometers that use the Hettrick–Underwood optical scheme, expanding their capabilities in materials research.
Dynamic analysis of a double-helical geared rotor system with oil-film bearing
Authors: Chen Ying-Chung , Yang Tsung-Hsien , Choi Siu-Tong
Published: April 2020

Purpose

This paper aims to study a dynamic analysis of a double-helical geared rotor system with oil-film bearing.

Design/methodology/approach

A finite element model of a double-helical geared rotor system with oil-film bearing is developed, in which a rigid mass is used to represent the gear and the Timoshenko beam finite element represents the shaft; the equations of motion are obtained by applying Lagrange’s equation. Natural frequencies, Campbell diagram, lateral responses, axial responses, bearing stiffness coefficients, bearing damping coefficients and bearing force are investigated.

Findings

Natural frequencies and Campbell diagram of a double-helical geared rotor system with oil-film bearing are investigated. An increased helical angle enhanced the axial response of the system and reduced its lateral response. The distance between the node and bearing affected the lateral response magnitude on the node. The farther away the gear pair was from the central part of the shaft, the higher the system’s resonance frequency became. The different gear pair position has a significant influence on the bearing stiffness coefficient and bearing force, but it just has a little effect on the bearing damping coefficient.

Practical implications

The model of a double-helical geared rotor system with oil-film bearing is established in this paper. The dynamic characteristics of a double-helical geared rotor system with oil-film bearing are investigated. The numerical results of this study can be used as a reference for subsequent personnel research.

Originality/value

Although the dynamics characteristics of geared rotor bearing system have been reported in some literature, the dynamic analysis of a double-helical geared rotor-bearing system is still rarely investigated. This paper showed some novel results that lateral and axial response results are obtained by the different helical angle and different gear positions. In the future, it makes valuable contributions for further development of dynamic analysis of a double-helical geared rotor-bearing system.
Characteristics of a co-flowing jet with varying lip thickness and constant velocity ratio
Authors: R. Naren Shankar , S. Kevin Bennett , N. Dilip Raja , K. Sathish Kumar
Published: April 2020

Purpose

This study aims to analyze co-flowing jets (CFJs) with constant velocity ratio (VR) and varying primary nozzle lip thickness (LT) to find a critical LT in CFJs below which mixing enhances and beyond which mixing inhibits.

Design/methodology/approach

CFJs were characterized with a constant VR and varying LTs. A single free jet with a diameter equal to that of a primary nozzle of the CFJ was used for characteristic comparison. Numerical simulation is carried out and is validated with the experimental results.

Findings

The results show that within a critical limit, the mixing enhanced with an increase in LT. This was signified by a reduction in potential core length (PCL). Beyond this limit, mixing inhibited leading to the elongation of PCL. This limit was controlled by parameters such as LT and constant VR. A new region termed as influential wake zone is identified.

Practical implications

In this study, the VR is maintained constant and bypass ratio (BR) was varied from low value to very high values. Presently, subsonic commercial turbo fan operates under low to ultra-high BR. Hence the present study becomes vital to the current scenario.

Originality/value

To the best of the authors’ knowledge, this is the first effort to find the critical value of LT for a constant VR for compressible co-flow jets. The CFJs with constant VR and varying LT have not been studied in the past. The present study focuses on finding a critical LT below which mixing enhances and above which mixing inhibits.
Water cycle algorithm-based PID controller for AVR
Authors: Pachauri Nikhil
Published: April 2020

Purpose

In a power system, the purpose of automatic voltage regulator (AVR) is the voltage control of synchronous generator. Power system stability and security depends on the AVR.

Design/methodology/approach

The present work is concentrated on the precise terminal voltage control of AVR system and simultaneously maintaining the stability of the system. Therefore, an optimal proportional–integral–derivative (PID) controller is proposed. An optimization technique inspired from Mother Nature, i.e. water cycle algorithm (WCA) is used to evaluate the optimum parameter values of PID controller leading to WCA-tuned PID (WCA-PID). The performance of WCA-PID is compared with other controller reported in the literature.

Findings

Simulation results show that WCA-PID regulates the terminal voltage more preciously and accurately in comparison to other controller. Further, it is more robust toward parametric uncertainty, set-point tracking and disturbance rejection in comparison to other controller reported in the literature.

Originality/value

The work is not published anywhere else.
Recognizing ragas of Carnatic genre using advanced intelligence: a classification system for Indian music
Authors: Kumaraswamy Balachandra , P G Poonacha
Published: April 2020

Purpose

In general, Indian Classical Music (ICM) is classified into two: Carnatic and Hindustani. Even though, both the music formats have a similar foundation, the way of presentation is varied in many manners. The fundamental components of ICM are raga and taala. Taala basically represents the rhythmic patterns or beats (Dandawate et al., 2015; Kirthika and Chattamvelli, 2012). Raga is determined from the flow of swaras (notes), which is denoted as the wider terminology. The raga is defined based on some vital factors such as swaras, aarohana-avarohna and typical phrases. Technically, the fundamental frequency is swara, which is definite through duration. Moreover, there are many other problems for automatic raga recognition model. Thus, in this work, raga is recognized without utilizing explicit note series information and necessary to adopt an efficient classification model.

Design/methodology/approach

This paper proposes an efficient raga identification system through which music of Carnatic genre can be effectively recognized. This paper also proposes an adaptive classifier based on NN in which the feature set is used for learning. The adaptive classifier exploits advanced metaheuristic-based learning algorithm to get the knowledge of the extracted feature set. Since the learning algorithm plays a crucial role in defining the precision of the raga recognition, this model prefers to use the GWO.

Findings

Through the performance analysis, it is witnessed that the accuracy of proposed model is 16.6% better than NN with LM, NN with GD and NN with FF respectively, 14.7% better than NN with PSO. Specificity measure of the proposed model is 19.6, 24.0, 13.5 and 17.5% superior to NN with LM, NN with GD, NN with FF and NN with PSO, respectively. NPV of the proposed model is 19.6, 24, 13.5 and 17.5% better than NN with LM, NN with GD, NN with FF and NN with PSO, respectively. Thus it has proven that the proposed model has provided the best result than other conventional classification methods.

Originality/value

This paper intends to propose an efficient raga identification system through which music of Carnatic genre can be effectively recognized. This paper also proposes an adaptive classifier based on NN.
Evaluation of the national research foundation-rated researchers’ output at a South African university
Authors: Bangani Siviwe , Onyancha Omwoyo Bosire
Published: April 2020

Purpose

The purpose of this paper is to establish the research impact of the National Research Foundation (NRF)-rated researchers’ output at the North-West University (NWU), South Africa, from 2006 to 2017.

Design/methodology/approach

The study used bibliometrics and altmetrics methods to determine the production of research outputs and the impact of NWU’s NRF-rated researchers’ publications. Various tools including Google Scholar (GS), Web of Science (WoS), Scopus, ResearchGate (RG) and Mendeley were used to collect data. The citations in the three bibliographic databases were used as proxy for academic impact, while reads and readerships in RG and Mendeley were used to determine societal impact of the researchers. The Statistical Package for the Social Sciences (SPSS) was used to test the relationship between citations in the three bibliographic databases and reads and readerships in RG and Mendeley.

Findings

The main findings were that the majority of NWU’s NRF-rated researchers’ publications emanated from GS, followed by Scopus and then WoS. GS output also had more citations. There were 6,026 research outputs in RG which were read for 676,919 times and 5,850 in Mendeley with 142,621 readerships. Correlations between RG and all three bibliographic databases’ citations were scant. Strong relationships between the three bibliographic databases’ citations and Mendeley readerships were found.

Practical implications

Academic librarians who interact with researchers who would like to predict future academic impact of their documents can be advised to consider Mendeley readerships with some level of confidence compared to RG reads. These results point to the importance of constant self-evaluation by researchers to ensure that they have balanced profiles across the three main bibliographic databases that are also considered for ratings. These results point to the relevancy of GS to evaluate research beyond the academy.

Social implications

The fact that researchers are contributing research that seeks to improve the general welfare of the population (beyond the academy) is a positive sign as society look up to researchers and research to solve their socio-economic problems. Social media play an important role as they serve as indicators that indicators point to wider research impacts and wider access by many different groups of people including the members of society at large. They point to research that is accessible to not only researchers and those who have access to their research but also the society at large.

Originality/value

Although the practice of rating researchers is common in different research ecosystems, the researchers could not find any evidence of studies conducted using a combination of bibliometrics and altmetrics to asses rated researchers’ output. This study covers and compares social impact based on data obtained from two academic social media sites and three main bibliographic databases (GS, Scopus and WoS).
How multiple large shareholders affect bank profitability under the dispersion and the coalition hypotheses? An insight from the MENA region
Authors: Boussaada Rim , Hakimi Abdelaziz
Published: April 2020

Purpose

The aim of this paper is to examine whether multiple large shareholders and their interactions affect bank profitability in the MENA region.

Design/methodology/approach

To achieve this goal, we used a sample of conventional banks in the MENA region observed during the period 2004–2015. We performed the System Generalized Method of Moment as the empirical approach.

Findings

Empirical results indicate that under the dispersion hypothesis, multiple large shareholders (MLS) tend to reduce bank profitability for both return on assets (ROA) and return on equity (ROE). However, under the alignment of interests’ hypothesis, coalition between the first and the second largest shareholder increases bank profitability only for ROA. We also find that an additional large shareholder, beyond the two largest, reduces bank return equity.

Originality/value

To the best of our knowledge, to date, there is no study that investigates the effect of MLS and the bank profitability in the MENA region. Indeed, this study shows the importance of considering ownership composition among large shareholders in banking studies.
Employee engagement in small and medium-sized enterprises in Thailand: the construction and validation of a scale to measure employees
Authors: Na-Nan Khahan , Pukkeeree Peerapong , Chaiprasit Kanokporn
Published: April 2020

Purpose

Employee engagement (EE) is an expression of a person's own preferred task behaviours that promote their relationship with work and personal physical, cognition and emotion and make them more active in terms of vigour, dedication and level of absorption with their work. To deal with EE in different environments and organisations, it is necessary to both understand and continually assess their employees. This paper presents an instrument which was developed to measure EE for small and medium-sized enterprises (SMEs) in Thailand.

Design/methodology/approach

The study was conducted in three stages to develop an EE measurement scale. To begin with, 18 questions were developed for a questionnaire based on the concepts of EE and validated using exploratory factor analysis (EFA) which is split into the dimensions of vigour, dedication and absorption. A survey was then conducted with 270 employees in SMEs. Finally, confirmatory factor analysis (CFA), convergence and validity were tested along the three engagement dimensions.

Findings

This research extended and broadened the EE concept to provide theoretical support for engaging with intelligence research. Three dimensions were developed to measure EE, including aspects of vigour, dedication and absorption with their work.

Research limitations/implications

The questionnaire used was produced primary data collection which was self-assessed, and data was collected only from the sample of employees working for SMEs in high-growth sectors of the Thai economy. The EE findings exhibited a good fit, but the results require further future refinement and validation using a larger sample size and sampling area.

Practical implications

The EE questionnaire has practical uses for monitoring management behaviour and can assist practitioners to assess the level of EE. This knowledge will help to encourage and support practitioners to improve EE. This research also provides other measurements for assessing EE in organisations.

Originality/value

The EE questionnaire validity will facilitate future studies on the boundaries of EE measurements in the context of SMEs. The empirical research results verified that EE assessment offered new perspectives to explore vital individual EE which is necessary for SMEs. This instrument can also support and help researchers to effectively understand EE and explore its potential in future studies.
International marketing agility: conceptualization and research agenda
Authors: Gomes Emanuel , Sousa Carlos M.P. , Vendrell-Herrero Ferran
Published: April 2020

Purpose

The aim of this paper is to conceptualize the notion of international marketing agility.

Design/methodology/approach

The approach adopted is to review and create a synopsis of the existing body of research on strategic agility and develop a conceptualization on how international marketing agility (IMA) should be analyzed.

Findings

International marketing agility is an emerging concept driven largely by rapid changes in global markets. There is a growing need for exporting SMEs and multinational enterprises to consider IMA as a means of building competitive advantage in foreign markets.

Research implications/limitations

While the conceptual development presented in this paper is not exhaustive, our model highlights important research avenues in IMA that need exploring.

Originality/value

This article examines an emerging concept in international marketing that serves as a platform to cope with the changes taking place in this fast-changing global environment. A framework is proposed where we conceptualize IMA as a process triggered by agile logic (a nonconformist and open mental stance) and facilitated by agile learning (being able to search and interpret data), to cause agile actions (being able to commit, co-ordinate and respond quickly with flexibility to ever-changing conditions).
Curvilinear performance effects of social cyberloafing out of class: the mediating role as a recovery experience
Authors: Wu Jinnan , Mei Wenjuan , Ugrin Joseph , Liu Lin , Wang Fang
Published: April 2020

Purpose

The purpose of this study is to investigate whether Chinese college students' social cyberloafing out of class has a curvilinear effect on academic performance and whether students' levels of psychological detachment and relaxation mediate the effect.

Design/methodology/approach

A field survey was used to collect 502 self-reported responses from student Internet users at a large university located in central China.

Findings

The results show an inverted U-shaped relationship between social cyberloafing out of class and academic performance. Two types of effort recovery experience gained from social cyberloafing, psychological detachment and relaxation, mediate that effect. Students' social cyberloafing out of class is positively associated with psychological detachment and relaxation, which in turn, have opposite effects on academic performance.

Practical implications

This study offers novel insights into the effects of social cyberloafing on college students' academic achievement. The findings illustrate how social cyberloafing can serve as a recovery experience and improve academic performance, but it can hinder performance if the cyberloafing is excessive.

Originality/value

This study extends the cyberloafing literature by focusing on Chinese college students' cyberloafing out of class. The study finds that a moderate amount of social cyberloafing out of class can result in psychological detachment, relaxation and improved performance when returning to academic work. However, both too much or too little social cyberloafing can result in difficulty returning to academic work and reduced academic performance. The findings are novel to the cyberloafing literature.
Cassava attractiveness in Nigeria: a policy improvement approach
Authors: Inegbedion Henry Egbezien , Inegbedion Emmanuel Edo , Obadiaru Eseosa David , Asaleye Abiola John , Ayeni Adebanji , Aremu Charity
Published: April 2020

Purpose

The study examined policy improvement and cassava attractiveness. The purpose was to determine the optimum rewards using three strategies: selling of farm produce to harvesters, making wholesale of harvested outputs and retailing harvested outputs.

Design/methodology/approach

Three hundred and sixty (360) cassava farmers were surveyed in three local government areas in Edo South senatorial district of Nigeria. From their responses, probabilities were assigned to rewards for each strategy from each of the locations. Subsequently, dynamic programming was employed in data analysis. Specifically, Howard policy improvement technique was used to forecast expected rewards to cassava farmers in the three local government areas using the three strategies.

Findings

Cassava farmers in Edo South senatorial district of Edo state, Nigeria, can maximize their earnings from cassava by retailing at the local markets in Oredo and Egor local government areas and by making wholesales at Ikpoba Okha local government area. Using this policy, they will realize approximately N2360 per basin and approximately N33040 per plot of 100 × 100 ft. This will translate to N143724 per acre (4.35 plots of 100 ft2).

Research limitations/implications

Availability of storage facilities as well as technical constraints to cassava production.

Social implications

Provision of jobs to the unemployed, thereby reducing the level of unemployment in the country.

Originality/value

Suggestion of the sales strategy that will yield optimum returns to cassava farmers, using policy iteration technique, and the projected estimates of the likely turnover when the strategy is adopted. This is a point of departure from previous studies. Thus, the study used operations research methodology to model solutions, through involvement in agriculture, to Nigeria's economic/financial problems, thus making it unique. In broad terms the study demonstrates that investment in agriculture will help to reduce unemployment and enhance the country's national income.