bluuebunny/crossref_metadata_2025 huggingface dataset:
ECMO During Combined Heart-Kidney Transplantation: A Case Report
Authors: Chazin Shai M. , Bresticker Michael A. , Chhabra Darshika , Mital Deepak , Desai Chaitanya R. , Slakey Douglas P.
Published: August 2019

Combined heart-kidney transplantation (CHKT) is a therapy for a carefully selected subgroup of patients with concomitant heart and kidney failure. Discerning whether there is reversible or irreversible kidney disease is crucial to selection for CHKT versus heart transplant alone to optimize therapeutic value and organ allocation. Methods for determining extent of kidney disease include estimating glomerular filtration rate, creatinine clearance, kidney ultrasonography, and kidney biopsy. Additionally, the use of extracorporeal membrane oxygenation (ECMO) in the setting of CHKT only recently emerged as feasible. We present a case of a 69-year-old man with cardiogenic shock who was placed on venoarterial-ECMO (VA-ECMO) following orthotopic heart transplant (OHT) due to severe mediastinal bleeding and remained on VA-ECMO during kidney transplant. To our knowledge, this is the second report of a patient undergoing kidney transplant while on VA-ECMO following OHT.
The role of industry in advancing xenotransplantation
Authors: Shin Jordan T. , Rothblatt Martine A. , Lorber Marc I.
Published: August 2019

Purpose of review

Xenotransplantation offers the opportunity to alleviate the imbalance between the demand of patients with end stage organ failure and the supply of organs available for transplantation but remains aspirational. This review highlights how collaboration between academia and industry are essential for success.

Recent findings

The science of xenotransplantation has accelerated in recent years with key discoveries in genetic engineering, enabling disruption of genes facilitating rejection, and transgenic expression of desired human genes. Combined with similar progress directed toward induction of transplant tolerance, the stage has been set for meaningful progress. These advances are reviewed in detail elsewhere in this volume and argue that the breakthroughs needed to deliver substantial cross-species organ survival have largely been achieved, heralding a liminal stage of human xenotransplantation. However, xenotransplantation as a meaningful therapy for medically refractory end organ failure will not be realized through scientific innovation alone. The advent of broadly available, therapeutic xenogeneic tissues requires extensive development and regulatory expertise; the biotechnology/pharmaceutical industry can provide extensive resources and expertise in those essential areas.

Successful delivery of xenotransplantation as an available therapy for curing end stage organ failure is best accomplished through partnership and collaboration between academia and industry.
Translabial Ultrasound Combined With Magnetic Resonance Imaging Assessing the Distensibility of Levator Ani Muscle With Unilateral High-Grade Tears
Authors: Luo Yijia , Zhou Minzhi , Ying Tao , Shui Wen , Dou Chaoran
Published: August 2019

Objectives

It is hypothesized that unilateral high-grade tears damage levator ani muscle (LAM) integrity and increase LAM distensibility. This study aimed to investigate how a unilateral high-grade tear caused overdistension of LAM and whether tear positions affect the degree of distension.

Methods

A total of 209 women were screened by translabial ultrasonography. Then, 18 nulliparous women with an intact LAM and 26 postpartum women with unilateral levator ani defects were recruited. The anteroposterior diameter (AP), coronal diameter (LR), and hiatal area (HA) of the minimum levator hiatus were recorded and compared for assessing the distensibility. All 44 subjects underwent magnetic resonance imaging for the diagnosis of levator ani defect and detection of tear positions. Within the software, 3-dimensional pelvic models were developed from magnetic resonance imaging scans for the direct visualization and measurements.

Results

Of the 26 postpartum women, 15 were diagnosed with unilateral high-grade tear (caudad in 9, cephalad in 6). The △AP, △LR, and △HA (Valsalva-rest) values of women with a unilateral high-grade tear were significantly larger than those of women with an intact LAM (P < 0.05). The △AP, △LR, and △HA (Valsalva-rest) values of cephalad tears were larger than those of women with caudad tears (P < 0.05).

Conclusions

A unilateral high-grade tear caused the overdistension of LAM. It was validated that cephalad tears caused higher degree of LAM distension than caudad tears.
Lightning and charge processes in brown dwarf and exoplanet atmospheres
Authors: Helling Christiane , Rimmer Paul B.
Published: August 2019

The study of the composition of brown dwarf atmospheres helped to understand their formation and evolution. Similarly, the study of exoplanet atmospheres is expected to constrain their formation and evolutionary states. We use results from three-dimensional simulations, kinetic cloud formation and kinetic ion-neutral chemistry to investigate ionization processes that will affect their atmosphere chemistry: the dayside of super-hot Jupiters is dominated by atomic hydrogen, and not H
2
O. Such planetary atmospheres exhibit a substantial degree of thermal ionization and clouds only form on the nightside where lightning leaves chemical tracers (e.g. HCN) for possibly long enough to be detectable. External radiation may cause exoplanets to be enshrouded in a shell of highly ionized, H
3
+
-forming gas and a weather-driven aurora may emerge. Brown dwarfs enable us to study the role of electron beams for the emergence of an extrasolar, weather system-driven aurora-like chemistry, and the effect of strong magnetic fields on cold atmospheric gases. Electron beams trigger the formation of H
3
+
in the upper atmosphere of a brown dwarf (e.g. LSR-J1835), which may react with it to form hydronium, H
3
O
+
, as a longer lived chemical tracer. Brown dwarfs and super-hot gas giants may be excellent candidates to search for H
3
O
+
as an H
3
+
product.

This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H
3
+
, H
5
+
and beyond’.
H
3
+
as an ionospheric sounder of Jupiter and giant planets: an observational perspective
Authors: Drossart Pierre
Published: August 2019

Thirty years of observations of

H

3

+

on Jupiter have addressed many complex questions about the physics of the ionospheres of the giant planets. Spectroscopy, imaging and imaging spectroscopy in the infrared have allowed investigators to retrieve fundamental parameters of the ionosphere, overcoming the inherent limitations and complexities in radiative transfer, and these results are now introduced as model constraints for upper atmospheric structure and dynamics. This paper will focus on the mid-latitude emissions, which are fainter and less well studied than the auroral regions. A new analysis of VLT/ISAAC spectral imaging observations of Jupiter obtained in 2000 at 3.5 µm is presented and discussed in comparison with previous observations to show the spatial distribution of

H

3

+

emissions compared with other atmospheric structures. Cylindrical maps of Jupiter in three different selected wavelengths show the spatial variations at different altitudes in the atmosphere, from cloud level up to the ionosphere. Evidence for fluctuations in the

H

3

+

emissions could be due to the presence of stationary or dynamic processes. If the exact origin of these phenomena remains unidentified, several plausible mechanisms are proposed to explain the observed energy deposition and variability: future observation campaigns should deepen the understanding of these complex phenomena, in order to prepare for the future ESA/JUICE mission.

This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H
3
+
, H
5
+
and beyond’.
Eating behavior trajectories in the first ten years of life and their relationship with BMI
Authors: Herle Moritz , De Stavola Bianca , Hübel Christopher , Santos Ferreira Diana L , Abdulkadir Mohamed , Yilmaz Zeynep , Loos Ruth , Bryant-Waugh Rachel , Bulik Cynthia M. , Micali Nadia
Published: August 2019

Background

Child eating behaviors are highly heterogeneous and their longitudinal impact on childhood weight is unclear. The objective of this study was to characterize eating behaviors during the first ten years of life and evaluate associations with BMI at age 11 years.

Method

Data were parental reports of eating behaviors from 15 months to age 10 years (n=12,048) and standardized body mass index (zBMI) at age 11 years (n=4884) from the Avon Longitudinal Study of Parents and Children. Latent class growth analysis was used to derive latent classes of over-, under-, and fussy eating. Linear regression models for zBMI at 11 years on each set of classes were fitted to assess associations with eating behavior trajectories.

Results

We identified four classes of overeating; “low stable” (70%), “low transient” (15%), “late increasing” (11%), and “early increasing” (6%). The “early increasing” class was associated with higher zBMI (boys: β=0.83, 95%CI:0.65, 1.02; girls: β=1.1; 0.92, 1.28) compared to “low stable”. Six classes were found for undereating; “low stable” (25%), “low transient” (37%), “low decreasing” (21%), “high transient” (11%), “high decreasing” (4%), and “high stable” (2%). The latter was associated with lower zBMI (boys: β=-0.79; -1.15, - 0.42; girls: β=-0.76; -1.06, -0.45). Six classes were found for fussy eating; “low stable” (23%), “low transient” (15%), “low increasing” (28%), “high decreasing” (14%), “low increasing” (13%), “high stable” (8%). The “high stable” class was associated with lower zBMI (boys: β =-0.49; -0.68 -0.30; girls: β =-0.35; -0.52, -0.18).

Conclusions

Early increasing overeating during childhood is associated with higher zBMI at age 11. High persistent levels of undereating and fussy eating are associated with lower zBMI. Longitudinal trajectories of eating behaviors may help identify children potentially at risk of adverse weight outcomes.
Special care is needed in applying phylogenetic comparative methods to gene trees with speciation and duplication nodes
Authors: Begum Tina , Robinson-Rechavi Marc
Published: August 2019

How gene function evolves is a central question of evolutionary biology. It can be investigated by comparing functional genomics results between species and between genes. Most comparative studies of functional genomics have used pairwise comparisons. Yet it has been shown that this can provide biased results, since genes, like species, are phylogenetically related. Phylogenetic comparative methods should allow to correct for this, but they depend on strong assumptions, including unbiased tree estimates relative to the hypothesis being tested. Such methods have recently been used to test the “ortholog conjecture”, the hypothesis that functional evolution is faster in paralogs than in orthologs. Whereas pairwise comparisons of tissue specificity (τ) provided support for the ortholog conjecture, phylogenetic independent contrasts did not. Our reanalysis on the same gene trees identified problems with the time calibration of duplication nodes. We find that the gene trees used suffer from important biases, due to the inclusion of trees with no duplication nodes, to the relative age of speciations and duplications, to systematic differences in branch lengths, and to non-Brownian motion of tissue-specificity on many trees. We find that incorrect implementation of phylogenetic method in empirical gene trees with duplications can be problematic. Controlling for biases allows to successfully use phylogenetic methods to study the evolution of gene function, and provides some support for the ortholog conjecture using three different phylogenetic approaches.
Role of synaptic inhibition in the coupling of the respiratory rhythms that underlie eupnea and sigh behaviors
Authors: Borrus Daniel S. , Conradi Smith Gregory D. , Del Negro Christopher A.
Published: August 2019

The preBötzinger Complex (preBötC) gives rise to two types of breathing behavior: eupnea and sighing. Here, we examine the neural mechanisms that couple their underlying rhythms by recording from the preBötC in neonatal mouse brainstem slice preparations. It has been proposed that chloride-mediated synaptic inhibition couples inspiratory (eupnea-related) bursts and sigh bursts, but we find no evidence to support that notion. First, we characterize a fluctuating temporal relationship between sigh bursts and their preceding inspiratory bursts; their coupling is far weaker than previously described. Surprisingly, selective blockade of inhibitory synapses strengthened (rather than weakened) that phasic inspiratory-sigh burst relationship. Furthermore, pharmacological disinhibition did not alter the duration of the prolonged interval that follows a sigh burst prior to resumption of the inspiratory rhythm. These results demonstrate that coupling between inspiratory and sigh rhythms does not depend on synaptic inhibition.

SIGNIFICANCE STATEMENT

Breathing consists of eupnea and sigh breaths, which differ in their magnitude and frequency. Both breath types emerge from a brainstem microcircuit that coordinates their timing. Here, we advance understanding of these rhythms by assessing the nature and strength of their coordination, and by showing that synaptic inhibition does not enforce their temporal coupling in contrast to conventional understanding. This study provides insights into the basic neural mechanisms that link oscillations of different amplitude and frequency in a core oscillator.
Mitochondrial fission is increased in macrophages during mROS production in response to S. pneumoniae
Authors: Mohasin Mohammed , Balbirnie-Cumming Katharin , Fisk Emily , Prestwich Elizabeth C. , Russell Clark D. , Marshall Jennifer , Pridans Clare , Allen Scott P. , Shaw Pamela J. , De Vos Kurt J. , Hill Christopher J. , Bullough Per , Condliffe Alison M. , Mitchell Tim J. , Marriott Helen M. , Dockrell David H.
Published: August 2019

Immunometabolism and regulation of mitochondrial reactive oxygen species (mROS) are critical determinants of the immune effector phenotype of differentiated macrophages. Mitochondrial function requires dynamic fission and fusion, but whether effector function is associated with altered dynamics during bacterial responses is unknown. We show that macrophage mitochondria undergo fission after 12 h of progressive ingestion of live Streptococcus pneumoniae (pneumococci). Fission is associated with progressive reduction in oxidative phosphorylation but increased mROS generation. Fission is enhanced by mROS production, PI3Kγ signaling and by cathepsin B, but not by inflammasome activation or IL-1β generation. Reduced fission following PI3Kγ or cathepsin B inhibition is associated with reduced mROS generation and bacterial killing. Fission is associated with Parkin recruitment to mitochondria, but not mitophagy. Fission occurs upstream of apoptosis induction and independently of caspase activation. During macrophage innate responses to live bacteria mitochondria shift from oxidative phosphorylation and ATP generation to mROS production and microbicidal responses with a progressive shift towards mitochondrial fission.
Human body prediction of size and shape: a hormonal framework
Authors: van Vugt Jeroen
Published: August 2019

To achieve high prediction accuracy with minimal inputs from online retail respondents, a method was developed and tested to predict the size and shape of the human body in 3D using a hormonal framework. The prediction method is based on geometric morphometrics, image analysis, and kernel partial least squares regression. The inputs required are answers to three closed-ended questions and a passport photo. Prediction accuracy was tested with the 3D body scan dataset of the Civilian American and European Surface Anthropometry Resource project. Results from the test dataset showed that approximately 82% of the error expectations of landmarks followed a log-normal distribution with an expectation of 8.816 mm and standard deviation of 1.180 mm. The remaining 18% of the error expectations of landmarks followed a log-normal distribution with an expectation of 18.454 mm and standard deviation of 8.844 mm, which may herald future research. Benchmarked with another method, the proposed method features much less input. In addition to high accuracy, the method in this paper allows for visualisation of results as real-size meshes in millimeters.
Surveying the landscape of tRNA modifications by combining tRNA sequencing and RNA mass spectrometry
Authors: Kimura Satoshi , Dedon Peter C. , Waldor Matthew K.
Published: August 2019

Chemical modification of the nucleosides that comprise tRNAs are diverse1-3. Such modifications impact tRNA structure, stability, and mRNA decoding3,4. Although tRNA modifications are present in all kingdoms of life1, the structure, location, and extent of modifications have been systematically charted in very few organisms, in part because mapping modifications to tRNA sequences has been technically challenging. Here, we describe a new approach in which rapid prediction of modified sites through reverse transcription-derived signatures in high-throughput tRNA-sequencing (tRNA-seq) data is coupled with chemical analysis and identification of tRNA modifications through RNA mass spectrometry (tRNA-SMS). As proof of concept, we applied this method to study tRNA modification profiles in two phylogenetically close bacteria,E. coliandVibrio cholerae. Comparative tRNA-seq enabled prediction of severalV. choleraemodifications that are absent fromE. coliand showed the effects of various environmental conditions onV. choleraetRNA modification profiles. Through RNA mass spectrometric analyses, we showed that two of theV. cholerae-specific reverse transcription signatures reflected the presence of a new modification (acetylated acp3U (acacp3U)), while another results from C-to-U RNA editing, a process not described before in bacteria. By combining comparative genomics with mass spectrometry, we identified a putative N- acetyltransferase required for acacp3U acetylation. These findings demonstrate the utility of the tRNA-SMS approach for rapid characterization of tRNA modification profiles and environmental control of tRNA modification. Moreover, our identification of a new modified nucleoside and RNA editing process suggests that there are many tRNA modifications awaiting discovery.
Yersiniabactin producing AIEC promote inflammation-associated fibrosis in gnotobioticIl10−/−mice
Authors: Ellermann Melissa , Gharaibeh Raad Z , Fulbright Laura , Dogan Belgin , Moore Lyndsey N , Broberg Christopher A. , Lopez Lacey R. , Rothemich Aaron M. , Herzog Jeremy W , Rogala Allison , Gordon Ilyssa O. , Rieder Florian , Brouwer Cory R. , Simpson Kenneth W. , Jobin Christian , Sartor R Balfour , Arthur Janelle C
Published: August 2019

Fibrosis is a significant complication of intestinal disorders associated with microbial dysbiosis and pathobiont expansion, notably Crohn’s disease (CD). Mechanisms that favor fibrosis are not well understood and therapeutic strategies are limited. Here we demonstrate that colitis susceptibleIl10-deficient mice develop inflammation-associated fibrosis when mono-associated with adherent/invasiveEscherichia coli(AIEC) that harbor the yersiniabactin (Ybt) pathogenicity island. Inactivation of Ybt siderophore production in AIEC nearly abrogated fibrosis development in inflamed mice. In contrast, inactivation of Ybt import through its cognate receptor FyuA enhanced fibrosis severity. This corresponded with increased colonic expression of profibrogenic genes prior to the development of histological disease, therefore suggesting causality.FyuA-deficient AIEC also exhibited greater localization within sub-epithelial tissues and fibrotic lesions that was dependent on Ybt biosynthesis and corresponded with increased fibroblast activationin vitro. Together, these findings suggest that Ybt establishes a pro-fibrotic environment in the host in the absence of binding to its cognate receptor and indicates a direct link between intestinal AIEC and the induction of inflammation-associated fibrosis.
A time resolved interaction analysis of Bem1 reconstructs the flow of Cdc42 during polar growth
Authors: Grinhagens Sören , Dünkler Alexander , Wu Yehui , Rieger Lucia , Brenner Philipp , Gronemeyer Thomas , Johnsson Nils
Published: August 2019

Cdc42 organizes cellular polarity and directs the formation of cellular structures in many organisms. By locating Cdc24, the source of active Cdc42, to the growing edge of the yeast cell, the scaffold protein Bem1 is instrumental in shaping the cellular gradient of Cdc42. This gradient instructs bud formation, bud growth, or cytokinesis through the actions of a diverse set of effector proteins. To address how Bem1 participates in this transformation we systematically mapped its protein interactions in time and space. SPLIFF analysis defined a unique ensemble of Bem1 interaction-states for each cell cycle stage. The characterization of mutants of Bem1 that interact with a discrete subset of the interaction partners allowed to assign specific functions to different interaction states and identified the determinants for their cellular distributions. The analysis characterizes Bem1 as a cell cycle specific shuttle that distributes active Cdc42 from its source to its effectors and helps to convert the PAKs Cla4 and Ste20 into their active conformation.
The study of lumbar ligamentum flavum hypertrophy induced in bipedal mice
Authors: Zheng Zhenyu , Qian Lei , Ao Xiang , Li Peng , Peng Yongxing , Chu Jun , Jiang Tao , Zhang Zhongmin , Wang Liang
Published: August 2019

Lumbar spinal stenosis (LSS) is a common degenerative disease among the elderly. The role that mechanical stress-induced hypertrophic ligamentum flavum (HLF) plays in patients with LSS remains unclear. Here, we used a finite element analysis to investigate the stress characteristics on the ligamentum flavum (LF) and evaluate the feasibility of a mouse model of HLF. First, we induced a bipedal posture in mice by taking advantage of their hydrophobia. A micro-CT scan was performed to examine their spinal change during bipedal posture. A finite element analysis showed that the stress and strain on the upright posture were significantly increased compared with those on the sprawling posture. Tissue staining showed that the degeneration degree of the LF in bipedal standing group gradually increased over the modeling period. The amount of elastic fibers decreased under HLF, whereas the amount of collagen fibers, the number of the LF cells, and the expression of fibrosis-related factors increased. Compared with aged group, LF degeneration was more severe in the bipedal standing group. Our findings demonstrate that the increased stress caused by a posture change causes HLF and that a bipedal mouse model can be used to study HLF in vivo.
UNC-10/SYD-2 links kinesin-3 to RAB-3-containing vesicles in the absence of the motor’s PH domain
Authors: Bayansan Odvogmed , Bhan Prerana , Chang Chien-Yu , Barmaver Syed Nooruzuha , Shen Che-Piao , Wagner Oliver Ingvar
Published: August 2019

Kinesin-3 KIF1A (UNC-104 inC. elegans) is the major axonal transporter of synaptic vesicles and mutations in this molecular motor are linked to KIF1A-associated neurological disorders (KAND) including Charcot-Marie-Tooth disease, amyotrophic lateral sclerosis and hereditary spastic paraplegia. UNC-104 binds via its PH (pleckstrin homology) domain to the lipid bilayers of membranous vesicles which is considered a weak interaction. RT-PCR and Western blot experiments reveal genetic relations between SYD-2, UNC-10 and RAB-3. Co-immunoprecipitation assays reveal functional relations and bimolecular fluorescence complementation (BiFC) assays exposein situinteractions between these proteins. Though both SNB-1 and RAB-3 are actively transported by UNC-104, the movement of RAB-3 is generally enhanced and largely depending on the presence of SYD-2/UNC-10. Deletion of UNC-104’s PH domain did not affect UNC-104/RAB-3 colocalization but did affect UNC-104/SNB-1 colocalization. Similarly, motility of RAB-3-labeled vesicles is unaltered in nematodes carrying a point mutation in the PH domain while movement of SNB-1 is significantly reduced in anterograde directions. These findings suggest a dual UNC-10/SYD-2 linker acting as a sufficient buttress to connect the motor to RAB-3-containing vesicles to enhance their transport. This additional linker will also strengthen the rather weak motor-lipid interaction.

Graphical abstract
PTP-3(LAR PTPR) promotes intramolecular folding of SYD-2(liprin-α) to inactivate UNC-104(KIF1A) in neurons
Authors: Shanmugam Muniesh Muthaiyan , Barmaver Syed Nooruzuha , Huang Hsin-Yi , Wagner Oliver Ingvar
Published: August 2019

This study aims to demonstrate how PTP-3 regulates SYD-2 to control UNC-104-mediated axonal transport. UNC-104 is theC. eleganshomolog of kinesin-3 KIF-1A known for its fast shuttling of STVs (synaptic vesicle protein transport vesicles) in axons. SYD-2 is the homolog of liprin-α inC. elegansknown to directly regulate UNC-104 as well as being a substrate of LAR PTPR (leukocyte common antigen-related (LAR) protein tyrosine phosphatase (PTP) transmembrane receptor) with PTP-3 as the closest homolog inC. elegans. CoIP assays revealed increased interaction between UNC-104 and SYD-2 in lysates fromptp-3knockout worms. Intramolecular FRET analysis revealed that SYD-2 predominantly exists in an open conformation state inptp-3mutants. These assays also revealed that non-phosphorylatable SYD-2 (Y741F) exists predominately in folded conformations while phosphomimicking SYD-2 (Y741E) exists predominantly in open conformations. Inptp-3mutants, SNB-1 cargo accumulates in soma while at the same time UNC-104 motors increasingly cluster along initial segments of axons. Interestingly, the unc-104 gene is downregulated inptp-3mutants that might explain the vesicle retention phenotype. More strikingly, the few visibly moving motors and STVs were overly active in neurons of these mutants. We propose a model in which the lack of PTP-3 promotes increased open conformations of SYD-2 that in turn facilitates UNC-104/SYD-2 interactions boosting motor and STVs moving speeds.
Solutions of time-fractional third- and fifth-order Korteweg–de-Vries equations using homotopy perturbation transform method
Authors: Karunakar Perumandla , Chakraverty Snehashish
Published: August 2019

Purpose

This study aims to find the solution of time-fractional Korteweg–de-Vries (tfKdV) equations which may be used for modeling various wave phenomena using homotopy perturbation transform method (HPTM).

Design/methodology/approach

HPTM, which consists of mainly two parts, the first part is the application of Laplace transform to the differential equation and the second part is finding the convergent series-type solution using homotopy perturbation method (HPM), based on He’s polynomials.

Findings

The study obtained the solution of tfKdV equations. An existing result “as the fractional order of KdV equation given in the first example decreases the wave bifurcates into two peaks” is confirmed with present results by HPTM. A worth mentioning point may be noted from the results is that the number of terms required for acquiring the convergent solution may not be the same for different time-fractional orders.

Originality/value

Although third-order tfKdV and mKdV equations have already been solved by ADM and HPM, respectively, the fifth-order tfKdV equation has not been solved yet. Accordingly, here HPTM is applied to two tfKdV equations of order three and five which are used for modeling various wave phenomena. The results of third-order KdV and KdV equations are compared with existing results.
Theoretical and numerical models for the influence of debonding on the interaction between hydraulic fracture and natural fracture
Authors: Wang Tao , Liu Zhanli , Gao Yue , Ye Xuan , Zhuang Zhuo
Published: August 2019

Purpose

The interaction between hydraulic fracture (HF) and natural fracture (NF) in naturally fractured rocks is critical for hydraulic fracturing. This paper aims to focus on investigating the development of tensile and shear debonding zone on the NF caused by the stresses produced by HF, and the influence of NF’s debonding behavior on the interaction between HF and NF.

Design/methodology/approach

Theoretically, tensile and shear debonding modes of NF are considered, two dimensionless parameters are proposed to characterize the difficulty of tensile and shear failure of NF, respectively. Numerically, a finite element model combining the extended finite element method and cohesive zone method (CZM) is proposed to study NF’s debonding behavior and its influence on the interaction between HF and NF.

Findings

Both theoretical analysis and numerical simulation show the existence of two debonding modes. The numerical results also show that the HF can cross, offset or propagate along the NFs depending on the parameters’ value, resulting in different fracture network and stimulated reservoir volume. When they are large, the NF’s debonding area is small, HF tends to cross the NF and the fracture network is simple; when they are small, the NF’s debonding area is large, HF will propagate along the NF. In addition, HF is easier to propagate along with NF under tensile debonding mode while it is easier to pass through NF under shear debonding mode.

Originality/value

The theoretical and numerical considerations are taken into account in the influence of the debonding of NFs on the interaction between HFs and NFs and the influence on the formation of the fracture network.
A stable high-order absorbing boundary based on continued fraction for scalar wave propagation in 2D and 3D unbounded layers
Authors: Li Huifang , Zhao Mi , Wu Lihua , Wang Piguang , Du Xiuli
Published: August 2019

Purpose

The purpose of this paper is to propose a stable high-order absorbing boundary condition (ABC) based on new continued fraction for scalar wave propagation in 2D and 3D unbounded layers.

Design/methodology/approach

The ABC is obtained based on continued fraction (CF) expansion of the frequency-domain dynamic stiffness coefficient (DtN kernel) on the artificial boundary of a truncated infinite domain. The CF which has been used to the thin layer method in [69] will be applied to the DtN method to develop a time-domain high-order ABC for the transient scalar wave propagation in 2D. Furthermore, a new stable composite-CF is proposed in this study for 3D unbounded layers by nesting the above CF for 2D layer and another CF.

Findings

The ABS has been transformed from frequency to time domain by using the auxiliary variable technique. The high-order time-domain ABC can couple seamlessly with the finite element method. The instability of the ABC-FEM coupled system is discussed and cured.

Originality/value

This manuscript establishes a stable high-order time-domain ABC for the scalar wave equation in 2D and 3D unbounded layers, which is based on the new continued fraction. The high-order time-domain ABC can couple seamlessly with the finite element method. The instability of the coupled system is discussed and cured.
Fragility curves production by seismic improvement of the high-dimensional model representation method
Authors: Asadi Payam , Sourani Hosein
Published: August 2019

Purpose

In the absence of random variables, random variables are generated by the Monte Carlo (MC) simulation method. There are some methods for generating fragility curves with fewer nonlinear analyses. However, the accuracy of these methods is not suitable for all performance levels and peak ground acceleration (PGA) range. This paper aims to present a method through the seismic improvement of the high-dimensional model representation method for generating fragility curves while taking advantage of fewer analyses by choosing the right border points.

Design/methodology/approach

In this method, the values of uncertain variables are selected based on the results of the initial analyses, the damage limit of each performance level or according to acceptable limits in the design code. In particular, PGAs are selected based on the general shape of the fragility curve for each performance limit. Also, polynomial response functions are estimated for each accelerogram. To evaluate the accuracy, fragility curves are estimated by different methods for a single degree of freedom system and a reinforced concrete frame.

Findings

The results indicated that the proposed method can not only reduce the computational cost but also has a higher accuracy than the other methods, compared with the MC baseline method.

Originality/value

The proposed response functions are more consistent with the actual values and are also congruent with each performance level to increase the accuracy of the fragility curves.
Punching in two-way RC flat slabs with openings and L section columns
Authors: Pinto Valdemir Colares , Branco Vitor , Oliveira Denio Ramam
Published: August 2019

Purpose

This study aims to contribute to a better understanding of the influence of the position of openings around L cross-section columns in reinforced concrete flat slabs through a nonlinear computational analysis compared to experimental results.

Design/methodology/approach

Tests on four reinforced concrete flat slabs of 1800 x 1800 x 120 mm3 were carried out under symmetrical punching; one slab was referenced (without hole) and three had square holes of 100 x 100 mm2 close to columns and with centroid on the critical perimeter at 0.5 d and 2.0 d of the loaded area. A nonlinear analysis of the slabs was performed to aid the interpretation and preview of the experimental results, and to estimate the ultimate loads and failure modes. These estimates followed recommendations of ACI 318, Eurocode 2, NBR 6118, MC 2010 and critical shear crack theory.

Findings

The results showed that the presence of holes in the analyzed regions does not influence significantly the behavior of the slabs, leading to conservative structural design once the ultimate load estimates are low, while the computational results adequately estimated the slabs’ behavior.

Research limitations/implications

A few limitations were observed on how to implement the correct modeling system for computational nonlinear simulation.

Practical implications

All design codes underestimated failure loads and the theoretical method was not much better. The nonlinear computational simulations were satisfactory, presenting results close to experimental ones (97 per cent accuracy). Computational simulation also showed that the presence of holes does not significantly influence the load-vertical displacement behavior or failure loads.

Social implications

Structural and civil engineers and designers can observe with better details the punching phenomenon and make take secure decisions to building projects. They can preview accurate cases that are not cited in design codes and literature.

Originality/value

This is a very rare subject in literature that interests the entire scientific community and especially reinforced concrete designers. Presenting a new methodology to nonlinear flat slab with openings modeling to punching shear provoked by L cross section columns, case that is not cited in literature and design codes.
Corporate social responsibility: a pathway to sustainable competitive advantage?
Authors: Shah Syed Shujaat Ali , Khan Zia
Published: August 2019

Purpose

The purpose of this paper is to investigate the impact of customers’ perceptions of corporate social responsibility (CSR) on affective and continuance commitment. It analyses the moderation effect of relationship age on the CSR-commitment relationships in the banking industry of an emerging economy.

Design/methodology/approach

Partial least squares based structural equation modeling was used to test the proposed hypotheses in a sample of 360 respondents collected from the retail banking sector of Pakistan.

Findings

Customers’ CSR perceptions directly and positively influence affective and continuance commitment. The findings also confirm that relationship age is a positive moderator of the CSR-continuance commitment relationship, but does not influence the CSR-affective commitment relationship.

Practical implications

Marketers should use CSR activities to enhance customers’ commitment. Given the moderating role of relationship age, marketers should devise different strategies for new and long-term customers. The results clearly show that relationship age affects the CSR-continuance commitment relationship. Long-term banking customers will more likely be in a binding relationship when their banks do CSR activities and disseminate those activities to long-term customers. The study explicitly indicates that maintaining long-term customers’ base through CSR activities helps the marketers in achieving sustainable competitive advantage.

Originality/value

First, it is the pioneering study to empirically investigate the understudied relationship between CSR and continuance commitment. Second, it examines the moderation effect of relationship age on CSR-commitment relationships in the banking industry of an emerging economy.
Measuring perceived procedural fairness in the context of power grid expansion
Authors: Mueller Christoph Emanuel , Keil Silke Inga
Published: August 2019

Purpose

Governments and energy operators are often confronted with opposition to the construction of new high-voltage transmission lines. Besides other factors, a potential determinant of public opposition and acceptance that has gained increasing attention is the fairness of the planning and approval procedure as perceived by the citizens. The purpose of this study is to develop and validate a scale for measuring perceived procedural fairness (PPF).

Design/methodology/approach

The authors developed the ten-item “perceived procedural fairness scale (PPFS)” and assessed its quality by means of item response theory. By using a Rasch rating scale model, the authors tested whether the instrument met the requirements of this kind of measurement model. For conducting their research, the authors used data from two telephone surveys in Germany that were collected in areas that are affected by grid expansion.

Findings

The findings suggest that the scale can be considered a reliable and internal valid instrument for measuring citizens’ PPF.

Originality/value

At the moment, there is no psychometrically rigorously evaluated scale available for measuring PPF in the context of power grid expansion. Therefore, the study contributes to filling this gap and provides a valuable tool for researchers and practitioners concerned with further investigating citizens’ PPF and its relationships with other relevant constructs in the field.
How can a low-income household procure small-scale hybrid renewable energy system?
Authors: Babatunde Olubayo Moses , Munda Josiah Lange , Hamam Yskandar
Published: August 2019

Purpose

The application of hybrid renewable energy system (HRES) can mitigate inadequate access to clean, stable and sustainable energy among households in sub-Saharan Africa (SSA). Available studies on HRES seem to concentrate only on its techno-economic and environmental viability. In so doing, these studies do not seem to underline the likely challenges that follow the acquisition of HRES by especially low-income households. The ensuing reality is, of course, a limitation in the use of HRES in homes with low incomes. It is therefore imperative to analyze how a household with low income can afford this kind of energy system. The purpose of this study, therefore, lies in presenting a techno-economic, environmental and affordability analysis of how HRES is acquired.

Design/methodology/approach

To arrive at a grounded analysis, a typical household in SSA is used as an example. The analysis focused on the pattern of energy use, and this is obtained by visiting an active site to evaluate the comprehensive load profile. In the course of analysis, an optimal techno-economic design and sizing of a hybrid PV, wind and battery were undertaken. Additionally, an acquisition analysis was done based on loan amortization.

Findings

The interesting result is that a combination of the photovoltaic-gasoline-battery system is the most cost-effective energy system with a net present cost of $2,682. The system combination can lead to an emission reduction of approximately 98.3 per cent, compared to the use of gasoline generating sets, common mostly in SSA. If an amortized loan is used to purchase the energy system, and the payment plan is varied such that the frequency of payments is made quarterly, annually, semi-annually, bi-monthly, semi-monthly and bi-weekly, it will be observed that low-income household can conveniently acquire a HRES.

Originality/value

The result presented a framework by which a low-income household can purchase and install HRES. To facilitate this, it is recommended that low-income households should be given interest-friendly loans, so as to enhance the acquisition of HRES.
The next phase in servitization: transforming integrated solutions into modular solutions
Authors: Rajala Risto , Brax Saara A. , Virtanen Ari , Salonen Anna
Published: August 2019

Purpose

The purpose of this paper is to identify integrated solutions business as the first generation of servitized offerings and modular solution offerings as the second development phase in servitization of original equipment manufacturers. This study examines how the servitized manufacturer, Kone, moves from integrated solutions to modular solutions business and develops the requisite capabilities to design, produce and implement modular solution offerings.

Design/methodology/approach

The paper reports a longitudinal case study of a provider of integrated solutions installed in buildings. During the ten years studied, the manufacturer implemented a strategic initiative to modularize its integrated solutions offering.

Findings

The firm’s transition to modular solutions progressed through three major capability development phases: solutions based onad hocintegration, smart solutions based on modular design and through-chain modularity. The modular structure aims at fostering the efficiency of the solution offering and the associated production system.

Research limitations/implications

Leveraging the benefits of modularity calls for an aligned combination of strategic, operational and technical capabilities contributing to the integration of resources in a modular production system for the solution providers’ competitive performance.

Practical implications

The study reports how a solution provider can develop the operational capabilities to integrate the core and peripheral components into the solution, and orchestrate the modular production system.

Originality/value

This study is a rare longitudinal analysis of how a manufacturer builds a modular offering, the solution platform and the required competitive capabilities to provide the solution.
Firm characteristics and export performance in Portuguese wine firms
Authors: Bashiri Behmiri Niaz , Rebelo João Fernandes , Gouveia Sofia , António Patrícia
Published: August 2019

Purpose

The purpose of this paper is to contribute to the determinants of export performance literature. The authors investigate the effect of firm characteristics on the Douro region wine firms export performance. The authors consider the Douro region, as it has the Portugal highest wine classification, the appellation d’origine contrôlée and undertakes the first position in the Portuguese wine production and export.

Design/methodology/approach

The authors apply a pooling cross-sectional data set that includes 427 observations. The authors pooled two cross sections consisting of 214 and 213 firms for the years 2014 and 215, respectively. The firm export intensity and propensity are the dependent variables. Moreover, the firm size, age and productive efficiency are accounted as the firm characteristics. The authors use the ordinary least squares regression and the tobit and probit models for estimations.

Findings

First, size is an influential factor to improve the export performance, and the importance of size is higher for younger firms. Second, there is a positive response from export intensity to age and this response is higher for smaller firms. However, there is a negative response from the export propensity to age and this negative response is higher for bigger firms. Third, there is weak evidence to support a relationship between efficiency and export performance.

Research limitations/implications

This research and the presented results are undoubtedly under some limitations. The main limitation is about the data availability for all characteristics of a firm. For example, it will enrich the result if the authors add some other important variables such as production cost, research and development expenditure and the quality of produced wine by each firm to our analysis.

Originality/value

This research reveals that the influence of firm characteristics on the export performance of Portuguese wine firms is missing in the literature. The results provide a basis to Portuguese wineries to improve their export performance by applying the relevant strategies.
What motivates Czech and international “millennial-aged” university students to consume craft beers?
Authors: Rivaroli Sergio , Kozák Vratislav , Spadoni Roberta
Published: August 2019

Purpose

An interesting subset of millennials are university students. This study aims to investigate motivations to drink craft beers in a sample of Czech and International University students in Prague (Czech Republic).

Design/methodology/approach

Adopting a revised model of the theory of planned behaviour (TPB), a simultaneous equations model was used by performing a three-stage least squares (3SLS) regression. The data were obtained from 305 students of 18 and 35 years of age (152 Czechs and 153 Internationals) at the Czech University of Life Sciences (CULS), who completed a face-to-face interview using a questionnaire.

Findings

The findings confirm the major role played by self-identity (SI) on the intention to drink craft beers, in the whole sample, and the key role played by the perception of being able to drink, for the Czechs participants only. Attitudes and social pressure towards craft beer consumption are of secondary importance, whereas the desire for uniqueness is not a relevant aspect in the participants’ decision of drinking craft beers.

Originality/value

The study deepened the TPB by incorporating consumers’ SI and the desire for unique consumer products as additional constructs to explain the intention of drinking craft beers. Given the long tradition of brewing in the Czech Republic and its significant role in the global marketplace, the understanding of local and foreign millennials’ intention to drink craft beers would contribute to increase knowledge on consumer behaviour, bringing beneficial effects to the brewing sector. Further research developments, within the context of handcrafted food consumption, stem from the discussion of the theoretical implications.