bluuebunny/crossref_metadata_2025 huggingface dataset:
MHY2013 Modulates Age-related Inflammation and Insulin Resistance by Suppressing the Akt/FOXO1/IL-1β Axis and MAPK-mediated NF-κB Signaling in Aged Rat Liver
Authors: Cho Mun Joo , Kim Dae Hyun , Ha Sugyeong , Bang EunJin , Jung Hee Jin , Moon Hyung Ryong , Chung Hae Young
Published: June 2019

Chronic inflammation is a major risk factor underlying aging and age-associated diseases. It impairs normal lipid accumulation, adipose tissue function, and mitochondrial function, which eventually lead to insulin resistance. Peroxisome proliferator-activated receptors (PPARs) critically regulate gluconeogenesis, lipid metabolism, and the lipid absorption and breakdown process, and PPAR activity decreases in the liver during aging. In the present study, we investigated the ability of 2-(4-(5,6-methylenedioxybenzo[d]thiazol-2-yl)-2-methylphenoxy)-2-methylpropanoic acid (MHY2013), synthesized PPARα/PPARβ/PPARγ pan agonist, to suppress the inflammatory response and attenuate insulin resistance in aged rat liver. Six- and 20-month-old rats were divided into 4 groups: young and old rats fed ad libitum; and old rats fed ad libitum supplemented with MHY2013 (1 mg and 5 mg/kg/d for 4 wk). We found that MHY2013 supplementation efficiently downregulated the activity of nuclear factor-κB through JNK/ERK/p38 mitogen-activated protein kinase signaling in the liver of aged rats. In addition, MHY2013 treatment increased hepatic insulin signaling, and the downstream signaling activity of FOXO1, which is negatively regulated by Akt. Downregulation of Akt increases expression of FOXO1, which acts as a transcription factor and increases transcription of interleukin-1β, leading to hepatic inflammation. The major finding of this study is that MHY2013 acts as a therapeutic agent against age-related inflammation associated with insulin resistance by activating PPARα, PPARβ, and PPARγ. Thus, the study provides evidence for the anti-inflammatory properties of MHY2013, and the role it plays in the regulation of age-related alterations in signal transduction pathways.
White Adipocytes of the Uterine Cervix Tend to Appear in Women of Older Age, Postmenopause Status, and Higher Body Mass Index
Authors: Yorita Kenji , Hirano Koki , Kai Yuka , Tanaka Yu , Takahashi Yohei
Published: June 2019

The human uterine cervix consists mainly of epithelium and stroma, including smooth muscle cells and fibrovascular tissues. Fat cells in the uterine cervix have been rarely reported, and the only previous research article has shown that intracervical adipocytes are unrelated to clinical factors. The aim of this study was to investigate the frequency of fat cells in the uterine cervix, as well as to evaluate the relationship between intracervical adipocytes and clinicopathologic factors. We retrospectively selected 405 cases in Japanese women who received cervical conization at our hospital between 2003 and 2017. Cervical conization was not performed during pregnancy or within 1 yr after childbirth. The prepared histologic specimens for pathologic diagnosis were available in all cases. Age, menopause status, body mass index, gravidity, and parity were selected clinical factors, which were obtained in 214 patients. The mean patient age was 42 yr (range, 22–80 yr). Intracervical white adipocytes were observed in 13% of patients (53/405), with no brown adipocytes detected. The existence of intracervical adipocytes was significantly correlated to older age (P<0.0001), postmenopause status (P<0.0001), and higher body mass index (P=0.0018). Intracervical adipocytes might undergo adipocytic metaplasia from cervical stromal cells in accordance with aging, postmenopause status, or weight gain. Our result also suggest that cervical malignancy involving fat cells does not necessarily imply parametrial invasion.
Delivering Opioid Overdose Prevention in Bars and Nightclubs: A Public Awareness Pilot in New York City
Authors: Allen Bennett , Sisson Laura , Dolatshahi Jennifer , Blachman-Forshay Jaclyn , Hurley Ariel , Paone Denise
Published: June 2019

Drug seizure data indicate the presence of fentanyl in the cocaine supplies nationally and in New York City (NYC). In NYC, 39% of cocaine-only involved overdose deaths in 2017 also involved fentanyl, suggesting that fentanyl in the cocaine supply is associated with overdose deaths. To raise awareness of fentanyl overdose risk among people who use cocaine, the NYC Department of Health and Mental Hygiene pilot tested an awareness campaign in 23 NYC nightlife venues. Although 87% of venue owners/managers were aware of fentanyl, no participating venues had naloxone on premises prior to the intervention. The campaign's rapid dissemination reached people at potential risk of opioid overdose in a short period of time following the identification of fentanyl in the cocaine supply. Public health authorities in states with high rates of opioid-involved overdose death should consider similar campaigns to deliver overdose prevention education in the context of a drug supply containing fentanyl.
Surgical Techniques for the Laparoscopic Treatment of Bile Duct Stones in Patients With a History of Upper Abdominal Operations: Retrospective Cohort Study
Authors: Tan Jie-hui , Zhou Lei , Zhang Guo-wei
Published: June 2019

Purpose:

Few authors have studied applying the laparoscopic approach in patients with previous upper abdominal operations, but no comparison has been made between laparoscopic and open approaches in patients with previous upper abdominal operations. This article aims to introduce surgical techniques and details in treatment to surgeons specialized in minimally invasive surgery.

Materials and Methods:

From January 2010 to January 2018, 460 eligible patients were divided into 3 groups and analyzed retrospectively. Group A: patients with a history of upper abdominal operations who underwent laparoscopy (n=124); group B: patients without a history of upper abdominal operations who underwent laparoscopy (n=140); and group C: patients with a history of upper abdominal operations who underwent an open operation (n=196). Group A was the experimental group; groups B and C served as the control groups.

Results:

No significant difference was found between groups A and B. Significant differences were found between groups A and C in estimated blood loss (258.3±67.2 vs. 424.7±103.7 mL, P<0.001), postoperative hospitalization (5.7±2.3 vs. 10.2±3.1 d, P<0.001), and postoperative complications (16.1% vs. 42.9%, P=0.013). The final rate of stones clearance was 100% in 3 groups. The total rate of stone recurrence was 7.8%.

Conclusions:

Laparoscopy with certain surgical techniques was feasible, effective, and advantageous for patients with previous upper abdominal operations by experienced surgeons. It is necessary for surgeons to have advanced skills and surgical techniques to achieve a successful laparoscopy.
Photovoltaic stimulation efficiently evokes network-mediated activity of retinal ganglion cells
Authors: Chenais Naïg A. L. , Airaghi Leccardi Marta J. I. , Ghezzi Diego
Published: June 2019

Objective

Photovoltaic retinal prostheses theoretically offer the possibility of standalone high-resolution electrical stimulation of the retina. However, in artificial vision, achieving locally selective epiretinal stimulation is particularly challenging, on the grounds of axonal activation and electrical cell coupling.

Approach

Here we show that electrical and photovoltaic stimulation of dystrophic retinal circuits with capacitive-like pulses leads to a greater efficiency for indirect network-mediated activation of retinal ganglion cells. In addition, a biophysical model of the inner retina stimulation is proposed to investigate the waveform and duration commitments in the genesis of indirect activity of retinal ganglion cells.

Main results

Both in-vitro and in-silico approaches suggest that the application of long voltage pulses or gradual voltage changes are more effective to sustainably activate the inner excitatory and inhibitory layers of the retina, thus leading to a reproducible indirect response. The involvement of the inhibitory feedback from amacrine cells in the forming of indirect patterns represents a novel biological tool to locally cluster the response of the retinal ganglion cells.

Significance

These results demonstrate that recruiting inner retina cells with epiretinal stimulation enables not only to bypass axonal stimulation but also to obtain a more focal activation thanks to the natural lateral inhibition. In this perspective, the use of capacitive-like waveforms generated by photovoltaic prostheses may allow improving the neural response resolution while standing high-frequency stimulation.
Mice with GNAO1 R209H Movement Disorder Variant Display Hyperlocomotion Alleviated by Risperidone
Authors: Larrivee Casandra L. , Feng Huijie , Quinn Josiah A. , Shaw Vincent S. , Leipprandt Jeffrey R. , Demireva Elena Y. , Xie Huirong , Neubig Richard R.
Published: June 2019

Neurodevelopmental disorder with involuntary movements (NEDIM, OMIM: 617493) is a severe, early onset neurological condition characterized by a delay in psychomotor development, hypotonia, and hyperkinetic involuntary movements. Heterozygous de novo mutations in the GNAO1 gene cause NEDIM. Gαo, the gene product of GNAO1, is the alpha subunit of Go, a member of the heterotrimeric Gi/o family of G-proteins. Go is found abundantly throughout the brain but the pathophysiological mechanisms linking Gαo functions to clinical manifestations of GNAO1-related disorders are still poorly understood. One of the most common mutant alleles among the GNAO1 encephalopathies is the c.626G>A or p.Arg209His (R209H) mutation. We developed heterozygous knock-in Gnao1+/R209H mutant mice using CRISPR/Cas9 methodology to assess whether a mouse model could replicate aspects of the NEDIM clinical pattern. Mice carrying the R209H mutation exhibited increased locomotor activity and a modest gait abnormality at 8-12 weeks. In contrast to mice carrying other mutations in Gnao1, the Gnao1+/R209H mice did not show enhanced seizure susceptibility. Levels of protein expression in multiple brain regions were unchanged from WT mice but the nucleotide exchange rate of mutant R209H Gαo was 9 times faster than WT. The atypical neuroleptic risperidone has shown efficacy in a patient with the R209H mutation. It also alleviated the hyperlocomotion phenotype observed in our mouse model but suppressed locomotion in WT mice as well. In this study, we show that Gnao1+/R209H mice mirror elements of the patient phenotype and respond to an approved pharmacological agent.
Evaluation of network architecture and data augmentation methods for deep learning in chemogenomics
Authors: Playe Benoit , Stoven Véronique
Published: June 2019

Abstract

Among virtual screening methods that have been developed to facilitate the drug discovery process, chemogenomics presents the particularity to tackle the question of predicting ligands for proteins, at at scales both in the protein and chemical spaces. Therefore, in addition to to predict drug candidates for a given therapeutic protein target, like more classical ligand-based or receptor-based methods do, chemogenomics can also predict off-targets at the proteome level, and therefore, identify potential side-effects or drug repositioning opportunities. In this study, we study and compare machine-learning and deep learning approaches for chemogenomics, that are applicable to screen large sets of compounds against large sets of druggable proteins. State-of-the-art drug chemogenomics methods rely on expert-based chemical and protein descriptors or similarity measures. The recent development of deep learning approaches enabled to design algorithms that learn numerical abstract representations of molecular graphs and protein sequences in an end-to-end fashion, i.e., so that the learnt features optimise the objective function of the drug-target interaction prediction task. In this paper, we address drug-target interaction prediction at the druggable proteome-level, with what we define as the chemogenomic neuron network. This network consists of a feed-forward neuron network taking as input the combination of molecular and protein representations learnt by molecular graph and protein sequence encoders. We first propose a standard formulation of this chemogenomic neuron network. Then, we compare the performances of the standard chemogenomic network to reference deep learning or shallow (machine-learning without deep learning) methods. In particular, we show that such a representation learning approach is competitive with state-of-the-art chemogenomics with shallow methods, but not ultimately superior. We evaluate the most promising neuron network architectures and data augmentation techniques, such as multi-view and transfer learning, to improve the prediction performance of the chemogenomic network. Our results shed new insights on the design of chemogenomics approaches based on representation learning algorithms. Most importantly, we conclude from our observations that a promising research direction is to integrate heterogeneous sources of data such as various bioactivity datasets, or independently, multiple molecule and protein attribute views, instead of focusing on sophisticated, yet intuitively relevant, encoder’s neuron network architecture.
Characterization of Mucosal Dysbiosis of Early Colonic Neoplasia
Authors: Hong Bo-young , Ideta Takayasu , Igarashi Yuichi , Tan Yuliana , DiSiena Michael , Mo Allen , Birk John W. , Forouhar Faripour , Devers Thomas J. , Weinstock George M. , Rosenberg Daniel W.
Published: June 2019

Aberrant crypt foci (ACF) are the earliest morphologically identifiable lesion in the colon that can be detected by high-definition chromoendoscopy with contrast dye-spray. Although frequently associated with synchronous adenomas, their role in colorectal tumor development, particularly in the proximal colon, is still not clear. The goal of this study was to evaluate the profile of colon-associated bacteria associated with proximal ACF and to investigate their relationship to the presence and subtype of synchronous polyps present throughout the colon. Forty-five subjects undergoing a screening or surveillance colonoscopy were included in this retrospective study. Our study cohort included a total of 16 subjects with no identifiable proximal lesions (either ACF or polyp), 14 subjects with at least 1 ACF but no polyp(s), and 15 subjects with both at least 1 ACF and a synchronous proximal polyp(s) detected at colonoscopy. Bacterial cells adherent to the epithelia of ACF and normal mucosa were visualized by in situ hybridization within confocal sections. Bacterial DNA isolated from biopsies was used to construct PCR amplicon libraries targeting the V4 hypervariable region of the 16S rRNA gene, which were then sequenced on the Illumina platform. ACF showed significantly greater heterogeneity in their bacterial profiles compared to normal mucosa. Interestingly, one of the bacterial community structures we characterized was strongly correlated with the presence of synchronous polyps. The observed dysbiosis is more prominent within the colonic epithelium that also harbors synchronous polyps. Finally using DNA-mass spectrometry to evaluate a panel of colorectal cancer hot-spot mutations present in the ACF, we found that several APC gene mutations (R1450*, R876*, S1465fs*3) were positively associated with the presence of Instestinibacter sp., whereas KRAS mutations (G12V, G12D) were positively correlated with Ruminococcus gnavus. This result indicates a potential relationship between specific colon-associated bacterial species and somatically acquired CRC-related mutations. Overall, our findings suggest that perturbations to the normal adherent mucosal flora may constitute a risk factor for early neoplasia, demonstrating the potential impact of mucosal dysbiosis on the tissue microenvironment and behavior of ACF that may facilitate (or impede) their progression towards more advanced forms of neoplasia.
Acid Experimental Evolution of the Extremely Halophilic Archaeon Halobacterium sp. NRC-1 Selects Mutations Affecting Arginine Transport and Catabolism
Authors: Kunka Karina S. , Griffith Jessie M. , Holdener Chase , Bischof Katarina M. , Li Haofan , DasSarma Priya , DasSarma Shiladitya , Slonczewski Joan L.
Published: June 2019

Background

Halobacterium sp. NRC-1 (NRC-1) is an extremely halophilic archaeon that is adapted to multiple stressors such as UV, ionizing radiation and arsenic exposure. We conducted experimental evolution of NRC-1 under acid stress. NRC-1 was serially cultured in CM+ medium modified by four conditions: optimal pH (pH 7.5), acid stress (pH 6.3), iron amendment (600 μM ferrous sulfate, pH 7.5), and acid plus iron (pH 6.3, with 600 μM ferrous sulfate). For each condition, four independent lineages of evolving populations were propagated. After 500 generations, 16 clones were isolated for phenotypic characterization and genomic sequencing.

Results

Genome sequences of all 16 clones revealed 378 mutations, of which 90% were haloarchaeal insertion sequences (ISH) and ISH-mediated large deletions. This proportion of ISH events in NRC-1 was five-fold greater than that reported for comparable evolution of E. coli. One acid-evolved clone had increased fitness compared to the ancestral strain when cultured at low pH. Seven of eight acid-evolved clones had a mutation within or upstream of arcD, which encodes an arginine-ornithine antiporter; no non-acid adapted strains had arcD mutations. Mutations also affected the arcR regulator of arginine catabolism, which protects bacteria from acid stress by release of ammonia. Two acid-adapted strains shared a common mutation in bop, which encodes the bacteriorhodopsin light-driven proton pump. Unrelated to pH, one NRC-1 minichromosome (megaplasmid) pNRC100 had increased copy number, and we observed several mutations that eliminate gas vesicles and arsenic resistance. Thus, in the haloarchaeon NRC-1, as in bacteria, pH adaptation was associated with genes involved in arginine catabolism and proton transport.

Conclusions

Our study is among the first to report experimental evolution with multiple resequenced genomes of an archaeon. Haloarchaea are polyextremophiles capable of growth under environmental conditions such as concentrated NaCl and desiccation, but little is known about pH stress. Halobacterium sp. NRC-1 (NRC-1) is considered a model organism for the feasibility of microbial life in iron-rich brine on Mars. Interesting parallels appear between the molecular basis of pH adaptation in NRC-1 and in bacteria, particularly the acid-responsive arginine-ornithine system found in oral streptococci.
TEAD4/YAP1/WWTR1 prevent the premature onset of pluripotency prior to the 16-cell stage
Authors: Frum Tristan , Watts Jennifer , Ralston Amy
Published: June 2019

In the mouse embryo, pluripotent cells arise inside the embryo around the 16-cell stage. During these early stages, Sox2 is the only gene whose expression is known to be induced specifically within inside cells as they are established. To understand how pluripotent cells are created, we investigated the mechanisms regulating the initial activation of Sox2 expression. Surprisingly, Sox2 expression initiated normally in the absence of both Nanog and Oct4, highlighting differences between embryo and stem cell models of pluripotency. However, we observed precocious, ectopic expression of Sox2 prior to the 16-cell stage in the absence of Yap1, Wwtr1, and Tead4. Interestingly, the repression of premature Sox2 expression was sensitive to LATS1/2 activity, even though it normally does not limit TEAD4/YAP1/WWTR1 activity during these early stages. Finally, we present evidence for direct transcriptional repression of Sox2 by YAP1/WWTR1/TEAD4. Taken together, our observations reveal that, while embryos are initially competent to express Sox2 as early as the 4-cell stage, transcriptional repression prevents the premature expression of Sox2, thereby restricting the pluripotency program to the stage when inside cells are first created.
Adaptation of Mycobacterium tuberculosis to biofilm growth is genetically linked to drug tolerance
Authors: Richards Jacob P. , Cai Wenlong , Zill Nicholas A. , Zhang Wenjun , Ojha Anil K.
Published: June 2019

Mycobacterium tuberculosis (Mtb) spontaneously grows at the air-medium interface forming pellicle biofilms, which harbor more drug tolerant persisters than planktonic cultures. The underlying basis for increased persisters in Mtb biofilms is unknown. Using a Tn-seq approach, we show here that multiple genes that are necessary for fitness of Mtb cells within biofilms, but not in planktonic cultures, are also important for their tolerance to a diverse set of stressors and antibiotics. Thus, development of Mtb biofilms appears to be associated with population enrichment, in which endogenous stresses presumably generated by challenging growth conditions within biofilm architecture select for cells that maintain tolerance to exogenous stresses including antibiotic exposure. We further observed that the intrinsic drug tolerance of constituent cells of biofilms determines the frequency of persisters: morphologically indistinguishable monoculture biofilms of a ΔpstC2A1 mutant hypersensitive to rifampicin harbor ∼20-fold fewer persisters than wild-type. These findings together allow us to propose that the selection of elite cells during biofilm development significantly contributes to the persister frequency. Furthermore, probing the possibility that the population enrichment is an outcome of unique environment within biofilms, we demonstrate biofilm-specific induction in the synthesis of isonitrile lipopeptides (INLP). Mutation analysis indicates that INLP is necessary for the architecture development of Mtb biofilms. In summary, the study offers an insight into persistence of Mtb biofilms under antibiotic exposure, while identifying INLP as a biomarker for further investigation of this phenomenon.

SIGNIFICANCE

The tuberculosis (TB) pathogen Mycobacterium tuberculosis (Mtb) is one of the deadliest bacterial pathogens known to mankind, and TB treatment is inefficient. A lengthy chemotherapy for TB is attributed to a small subpopulation of Mtb bacilli exhibiting phenotypic tolerance to antibiotics. Drugs targeting these persisters are expected to shorten TB chemotherapy, but their development is dependent on in vitro growth models that reproducibly generate high frequency of persisters. Biofilms of Mtb are a suitable model for understanding the origin of persisters. Here, we provide an explanation for the elevated persister frequency in Mtb biofilms. We also identify isonitrile lipopetides as a biomarker of Mtb biofilms. These findings will facilitate further advancements of our efforts to identify and target Mtb persisters.
Paired-end Mappability of Transposable Elements in the Human Genome
Authors: Sexton Corinne E , Han Mira V
Published: June 2019

Though transposable elements make up around half of the human genome, the repetitive nature of their sequences makes it difficult to accurately align conventional sequencing reads. However, in light of new advances in sequencing technology, such as increased read length and paired-end libraries, these repetitive regions are now becoming easier to align to. This study investigates the mappability of transposable elements with 50bp, 76bp and 100bp paired-end read libraries. With respect to those read lengths and allowing for 3 mismatches during alignment, over 68%, 85%, and 88% of all transposable elements in the RepeatMasker database are uniquely mappable, suggesting that accurate locus-specific mapping of older transposable elements is well within reach.
Practical and safe method of cryopreservation for clinical application of human adipose-derived mesenchymal stem cells without a programmable freezer or serum
Authors: Gao Siqiang , Takami Akiyoshi , Takeshita Kyosuke , Niwa Reiko , Kato Hidefumi , Nakayama Takayuki
Published: June 2019

Background

Adipose-derived mesenchymal stem cells (ADSCs) have emerged as a promising therapeutic modality for cellular therapy because of their rapid proliferation and potent cellular activity compared to conventional bone marrow-derived mesenchymal stem cells (MSCs). Cosmetic lipoaspirates provide an easily obtainable source of ADSCs. Cryopreservation facilitates their clinical application due to increased transportability and pooling of sufficient numbers of cells. However, proper cryopreservation techniques have not been established yet.

Methods

We evaluated the post-thaw viability and ADSC functions after cryopreservation with three cryoprotectants (serum containing 10% dimethylsulfoxide (DMSO), serum-free: CP-1TM, DMSO-free: SCB-DFTM) at two temperature (−80°C, −150°C) and two cell densities: (1 × 106, 7 × 106cells/mL) for up to 18 months using cryovials. After determining optimal conditions, we also tested if large quantities of ADSCs remained viable after 18 months of cryopreservation in a 100-mL cryobag. Rate-controlled freezing methods or liquid nitrogen storage were not exploited.

Results

ADSCs cryopreserved in serum containing 10% DMSO or CP-1TMat −150°C and 7 × 106cells/mL were most viable (>85%) after 18 months without perturbation of MSC functions. Even suboptimal conditions (−80°C, 1 × 106cells/mL, no DMSO) assured >80% viability when stored for up to 9 months. Large quantities of ADSCs in a cryobag were properly cryopreserved.

Conclusions

A programmable freezer or liquid nitrogen storage is not necessary. CP-1TMis preferable in terms of side effects. Simplified cryopreservation methods (−80°C and no DMSO) can be used for up to 9 months, resulting in reduced infusion toxicities and lower costs.
Mindfulness for teachers: notes toward a discursive cartography
Authors: Low Remy
Published: June 2019

Purpose

For the interested teacher, teacher educator and educational researcher seeking an entry point into how mindfulness relates to teachers’ work, the burgeoning and divergent appeals for the relevance of mindfulness to teachers can be bewildering. The purpose of this paper is to offer teachers, teacher educators and educational researchers a conceptual framework for understanding the different orientations and sources of mindfulness as it has been recommended to teachers.

Design/methodology/approach

Using Foucault’s (1972) concept of “discursive formations” as a heuristic device, this paper argues that mindfulness as pitched to teachers can be helpfully understood as arising from three distinct orientations.

Findings

Statements about mindfulness and its relevance to teachers emerge from three distinct discursive formations – traditional, psychological and engaged – that each constitute the “problem” faced by teachers respectively as suffering, stress or alienation. Specific conceptions of mindfulness are then advanced as a solution to these problems by certain authoritative subjects and institutions in ways that are taken as legitimate within each discursive formation.

Originality/value

Apart from offering a historical and discursive mapping of the different discursive formations from which mindfulness is pitched to teachers, this paper also highlights how each of these orientations impies a normative view of what a teacher should be. Suggestions for further historical research are also offered along the lines of genealogy, epistemology and ontology.
Thermohydraulics of the liquid films in rotating heat pipes
Authors: Hooman Kamel , Safaei Mohammad Reza , Togun Hussein , Dahari Mahidzal
Published: June 2019

Purpose

In this study, closed-form solutions are presented to investigate thermohydraulics of liquid films in a rotating heat pipe. The film thickness is expressed as a function of flow rate.

Design/methodology/approach

Further, sensitivity of both film thickness and flow rate to the length of the rotating heat pipe can now be investigated using the explicit expressions presented here.

Findings

To make it easier for practical application, an approximate solution is presented on top of the exact solution.

Originality/value

Both approximate and exact solutions are then applied to note that results are in good agreement when compared to those available in the literature.
Experimental and numerical analysis of heat transfer in the helically coiled heat exchanger
Authors: Sobota Tomasz
Published: June 2019

Purpose

The knowledge of the heat transfer coefficient is important for the proper design of heat exchangers as well as for the determination of the working medium outlet temperatures. This paper aims to present a method of simultaneous determination of coefficients in correlation formulas for the Nusselt number on both sides of the heat transfer surface.

Design/methodology/approach

The idea of the developed method is based on determining such a values of the coefficients in Nusselt number correlations that fulfill the condition of equality between the measured and calculated temperature at the outlet of heat exchanger in terms of least squares method. To test the proposed method, a special experimental installation was built. The heat transfer in helically coiled tube-in-tube heat exchanger was examined for the wide range of temperature changes and volumetric flow rates of working fluid.

Findings

The simulation results were validated with an experimental data. The results show that the heat transfer coefficient of the counter-current is higher than the co-current flow in helically coiled heat exchanger. This phenomenon can be beneficial particularly in the laminar flow regime.

Research limitations/implications

The correlation for the Nusselt number as a function of the Reynolds and Prandtl numbers for hot and cold liquid was obtained with the least squares method for the experimental data.

Practical implications

The presented method allows for the simultaneous determination of heat transfer coefficient on both sides of the wall without the necessity of indirect calculation of the overall heat transfer coefficient. The presented method can be used in the thermal design of various type heat exchangers.

Originality/value

This work presents the new methodology of determination correlations for the helically coiled tube-in-tube heat exchanger for co-current and counter-current arrangement, which can be used in thermal design.
A novel heat sink design for simultaneous heat transfer enhancement and pressure drop reduction utilizing porous fins and magnetite ferrofluid
Authors: Bezaatpour Mojtaba , Goharkhah Mohammad
Published: June 2019

Purpose

With development of the modern electronic and mechanical devices, cooling requirement has become a serious challenge. Innovative heat transfer enhancement methods are generally accompanied by undesirable increase of pressure drop and consequently a pumping power penalty. The current study aims to present a novel and easy method to manufacture a mini heat sink using porous fins and magnetite nanofluid (Fe3O4/water) as the coolant for simultaneous heat transfer enhancement and pressure drop reduction.

Design/methodology/approach

A three-dimensional numerical study is carried out to evaluate the thermal and hydrodynamic performance of the mini heat sink at different volume fractions, porosities and Reynolds numbers, using finite volume method. The solver specifications for discretization of the domain involve the SIMPLE, second-order upwind and second order for pressure, momentum and energy, respectively.

Findings

Results show that porous fins have a favorable effect on both heat transfer and pressure drop compared to solid fins. Creation of a virtual velocity slip on the channel-fin interfaces similar to the micro scale conditions and the flow permeation into the porous fins are the main mechanisms of pressure drop reduction. On the other hand, the heat transfer enhancement is attributed to the increase of the solid-fluid contact area and the improvement of the flow mixing because of the flow permeation into the porous fins. An optimal porosity for maximum convective heat transfer enhancement is obtained as a function of Reynolds number. However, taking both pressure drop and heat transfer effects into account, the overall heat sink performance is shown to be improved at high of Reynolds numbers, volume fractions and fin porosities.

Research limitations/implications

Thermal radiation and gravity effects are ignored, and thermal equilibrium is assumed between solid and fluid phases.

Originality/value

A maximum of 32 per cent increase of convective heat transfer is achieved along with a maximum of 33 per cent reduction in the pressure drop using porous fins and ferrofluid in heat sink.
Tourism and involvement of inhabitants in Paris
Authors: Loisy Marine
Published: June 2019

Purpose

The purpose of this paper is to examine the adaptation strategies of inhabitants and the forms of participation they adopt in tourism activities in Paris. As public policies have recently recognized the importance of taking into account inhabitants in the tourism development strategy in Paris and its suburbs, this paper proposes an analysis of the different forms of this participation and its stakes for the territories.

Design/methodology/approach

This paper gathers the first results of a thesis work in anthropology that is based on an ethnographic method combining participant observation, semi-directive interviews and bibliographic work. Observations took place in Paris and in several cities of the Grand Paris with inhabitants involved in tourism activities, or who are experiencing a difficult cohabitation with tourists in their neighborhoods. Thus, some 40 semi-directive interviews were conducted with inhabitants, members of associations and entrepreneurs. There were also participatory observation works within public institutions, mainly at the Paris City Hall, as well as interviews with dozens of tourism professionals from the private, public and associative sectors.

Findings

Not all residents have the same commitment to tourism and they do not all want to meet visitors. The relationship of inhabitants to tourism is complex and heterogenous. Nevertheless, this research shows that the roles played by inhabitants are multiple: producers of tourist services, ambassadors for their city or neighborhood, the permanent resident can also be seen as a product that attracts visitors, and as a tourist himself. The permanent resident offers the possibility of going off the beaten track, and promotes the revalorization of the identity of a territory and its inhabitants.

Originality/value

The originality of this research lies in the choice to focus primarily on the point of view of the visited population in a European capital. Ethnographic work allows for the observation and analysis of practices, in order to understand the stakes of visitor/visitor cohabitation and to anticipate possible movements of anti-tourist rejections.
Barriers of embedding big data solutions in smart factories: insights from SAP consultants
Authors: Li Shuyang , Peng Guo Chao , Xing Fei
Published: June 2019

Purpose

Big data is a key component to realise the vision of smart factories, but the implementation and usage of big data analytical tools in the smart factory context can be fraught with challenges and difficulties. The purpose of this paper is to identify potential barriers that hinder organisations from applying big data solutions in their smart factory initiatives, as well as to explore causal relationships between these barriers.

Design/methodology/approach

The study followed an inductive and exploratory nature. Ten in-depth semi-structured interviews were conducted with a group of highly experienced SAP consultants and project managers. The qualitative data collected were then systematically analysed by using a thematic analysis approach.

Findings

A comprehensive set of barriers affecting the implementation of big data solutions in smart factories had been identified and divided into individual, organisational and technological categories. An empirical framework was also developed to highlight the emerged inter-relationships between these barriers.

Originality/value

This study built on and extended existing knowledge and theories on smart factory, big data and information systems research. Its findings can also raise awareness of business managers regarding the complexity and difficulties for embedding big data tools in smart factories, and so assist them in strategic planning and decision making.
Examining social capital and participation in networking sites
Authors: Varshney Tanya , Rajwanshi Rohit
Published: June 2019

Purpose

The purpose of this paper is to understand the internet user behavior, in an online environment, varying due to benefits and risks of social networking sites (SNS). This study focuses on the influence of benefits and risks of SNS on an internet user’s participation and tests the developed research framework.

Design/methodology/approach

A conceptual framework has been developed after reviewing relevant literature followed by hypothesis framing. The framework considers two benefits of using SNS, i.e., utilitarian and hedonic benefits, and two risks online, i.e., word-of-mouth skepticism and online privacy concerns, determining the effect of these four variables on online participation and its effect on online social capital. An advanced PLS-SEM has been used to test the research hypothesis and to test framework. This study is based on a descriptive survey and the data have been collected using online questionnaires. The users of SNS have been targeted as respondents using purposive sampling method.

Findings

This study proposed a positive relationship of utilitarian benefits with online participation while negative relationship of word-of-mouth (WOM) skepticism, and it affirms that online participation is linked significantly in a positive manner with online social capital.

Practical implications

The study is limited to some specific aspects of SNS, and other dimensions may provide newer scope for this research. The research provides a managerial implication, depicting that inculcation of benefit factors and reduction in the risk factors into the SNS or company websites would lead to an increased participation of users.

Originality/value

This research signifies the potential for further research and recommends the tactics for companies to use SNS by identifying benefit factors that encourage participation and it also recommends to proactively take steps to minimize effects of potential risks and challenges in an online environment.
Market-based pricing in B2B service industries
Authors: Indounas Kostis
Published: June 2019

Purpose

The purpose of this paper is to investigate the pricing objectives that business-to-business (B2B) service companies pursue to set their prices and to examine the impact of market structure on these objectives.

Design/methodology/approach

To achieve the research objectives, data were collected from 193 companies operating in four different B2B service industries.

Findings

The findings of the study indicate that, in the current study, the companies investigated seem to follow various pricing objectives with a particular emphasis being placed on customer-related ones. The study also reveals that the market structure does have an impact on the pricing objectives pursued because different market conditions are found to lead to different pricing objectives.

Practical implications

The above findings indicate that the managers responsible for setting prices within their firms should follow a “situation-specific approach” and be guided by the unique characteristics of their markets.

Originality/value

Given the lack of similar studies in the existing B2B services literature, the value of the paper is that it represents one of the first attempts to empirically examine this issue.
Organizing supplier interfaces in technological development
Authors: Lind Frida , Melander Lisa
Published: June 2019

Purpose

The purpose of this paper is to investigate supplier interfaces in technological development.

Design/methodology/approach

The theoretical framework is based on the industrial network approach and, in particular, the concept of supplier interfaces (standardized, specified, translational and interactive). The empirical study consists of a case study of a supplier relationship between an established truck manufacturer and one of its partners in technological development. This supplier relationship has its base in joint projects on developments in automation.

Findings

The empirical study provides evidence of three types of interfaces that are characteristic of technological development and discusses their development and how they are used in combination. The three types are follows: specified, translational and interactive. The conclusions show that developing an interface from specified to translational or interactive is challenging and technological development characterized by uncertainty may call for certain interfaces that are not of value in other settings, such as industrial production.

Originality/value

By applying the interface concepts to technological development in collaboration with suppliers and related identifying characteristic interfaces, this paper aims to extend the literature on how suppliers can be engaged in uncertain endeavours such as development projects.
The impact of software company size and culture on commercial real estate location and design
Authors: Starr Christopher W. , Starr Eliza Ruth , Worzala Elaine
Published: June 2019

Purpose

This paper aims to investigate the relationship of software company culture and core values and project management methodologies on the demand for corporate real estate (CRE), impacting decisions regarding location, square footage, office design and amenities.

Design/methodology/approach

A researcher-administered survey was designed with the assistance of a purposive sample of brokers, architects and interior designers to elicit responses from the CRE officers in software companies at four stages of growth, from small, entrepreneurial startups to large, publicly traded software companies, located in the same metropolitan area of the USA. Quantitative responses are summarized with traditional statistics and data visualizations. Linguistic analysis, including sentiment analysis and keyword relevance, was performed on the unstructured, English text responses.

Findings

Differences exist in the office layouts, amenities and locations across the four software company size categories studied. Linguistic analysis of company descriptions of office design, culture and core values, and the relationship between the two, provide another way for brokers, investors and other stakeholders to understand company perspectives and communication idioms related to CRE needs. The research was unable to show any differences in any dependent variable based on software project management methodologies due to sampling limitations.

Research limitations/implications

This study is limited by the sample size of the participating software companies based on access to company leadership. Results are not generalizable.

Practical implications

Architects, investors, brokers and lenders may find value in using this study’s approach to better understand the needs of software technology clients. Specifically, stakeholders may find value in examining the linkage from software company size, culture and core values to CRE office layout, amenities and location.

Originality/value

The qualitative findings suggest that software company culture and core values and company size influence the design of the CRE demanded by software companies. Multivariate data visualization was designed to communicate longitudinal CRE data. Linguistic analysis was used to extract the emotional content and relevance scores from company descriptions of office design, company culture and core values and the reported effect of culture and core values on office design. Findings may be beneficial for stakeholders involved in the design, location and future CRE investments, and they suggest the need for future research on a larger sample.
Leading school change and improvement
Authors: Kovačević Jasna , Hallinger Philip
Published: June 2019

Purpose

The purpose of this paper is to quantitatively document and synthesize the knowledge base on leading school change and improvement (LSCI).

Design/methodology/approach

The authors employed bibliometric analysis to evaluate 1,613 SCOPUS-indexed documents on LSCI published between 1960 and the end of 2017. In addition to descriptive analysis of basic features of the knowledge base, the review also employed citation and co-citation analyses of authors, journals and documents. Author co-citation analysis (ACA) was used reveal the intellectual structure of the LSCI literature.

Findings

The growth trajectory of LSCI research began with low levels of publication during the 1960s and 1970s, followed by steady and then accelerating growth in subsequent decades. Citation analyses highlighted key journals, authors and documents in this field, while ACA identified four research streams or Schools of Thought that comprise the LSCI knowledge base: transformational leadership for school improvement, instructional leadership for school improvement, shared leadership for change and school improvement, school improvement.

Originality/value

The review offers empirical documentation of the changing intellectual structure of the one of the key lines of inquiry that emerged in the field of educational administration over the past six decades. More broadly, the review illustrates the benefits of bibliometric analysis as a tool capable of illuminating critical features that bear upon knowledge accumulation in a line of inquiry, or a broader discipline.
What influences Chinese fashion retail? Shopping motivations, demographics and spending
Authors: Parker Christopher J. , Wenyu Lu
Published: June 2019

Purpose

The purpose of this paper is to establish the influence of shopping motivations on Chinese fashion retail engagement relative to demographics, monthly spend on fashion items and high street/electronic commerce (e-commerce) preference. This is to determine how international fashion retailers should design more effective retails channels, expanding upon established theory in Hedonic and utilitarian motivations. While earlier research suggests shopping motivations associate with demographics while influencing retail channel preference and consumer spending, much of this exploration is Western focused, with all variables being influential. However, the degree to which these apply to China, and the unique fingerprint of influential motivations remains unknown. This paper answers these questions to allow international retailers to develop more efficient marketing strategies and design more effective retail channels.

Design/methodology/approach

In all, 403 Chinese consumers generalisable to the broader population were surveyed on their hedonic and utilitarian motivations to shop for fashion apparel in high street and e-commerce environments. Statistical analysis was commenced through direct logistic regression and MANOVA.

Findings

Demographics have limited association with shopping motivations, with gender and age only producing small effect sizes, while occupation, income and education has no significance. High street store preference is influenced by adventure and social shopping and e-commerce preference only by idea shopping. Spending over ¥1k per month on fashion apparel is influenced by gratification and idea shopping, and regular spending habits inspired by value shopping.

Originality/value

This empirical paper characterises the fingerprint of shopping motivations’ influence as singular to China while proving their limitation and need for a wider plethora of influential factors to be recognised.