bluuebunny/crossref_metadata_2025 huggingface dataset:
The utility of clinical ultrasonography in identifying distal forearm fractures in the pediatric emergency department
Authors: Galletebeitia Laka Iratxe , Samson Frederic , Gorostiza Inigo , Gonzalez Andrés , Gonzalez Carlos
Published: October 2017

Objective

The aim of this study is to evaluate the utility of Point-Of-Care Ultrasound (POCUS) for diagnosing distal forearm fractures in pediatric emergency departments (ED).

Patients and methods

A prospective observational study was carried out in children aged younger than 15 years attended in an ED with an indication of radiography because of a suspected distal forearm fracture. The POCUS was performed considering cortical irregularity or disruption compatible with fracture. Then, the radiography was requested and the patient was evaluated by an ED traumatologist. Both tests were blinded to each other. The radiograph was considered to be the reference diagnostic test. Diagnostic validation tests were performed.

Results

A total of 115 patients [mean age: 9.1 (SD: 3.1) years; 50.4% males] were included, with 57 of these presenting fractures: 42 (73.7%) single bone fractures and 15 (26.3%) combined fractures of the radius and ulna. As such, 72 fractures were detected (prevalence 31.3%). The sensitivity and specificity of POCUS for detecting fractures were 94.4% [95% confidence interval (CI): 86.4–98.5] and 96.8% (95% CI: 92.8–99.0), respectively. The positive and negative predictive values were 93.2% (95% CI: 84.7–97.7) and 97.5% (95% CI: 93.6–99.3), respectively.

Conclusion

POCUS enables the clinical diagnosis of distal forearm fractures in ED. In addition, this is a highly accurate technique that can be applied easily by the ED pediatrician. As such, its inclusion as part of the physical examination could improve the accuracy of the clinical diagnosis and the global management of the patient.
Ethnic Disparity in the Incidence and Outcome of Biliary Atresia in New Zealand
Authors: Evans Helen M. , Asher M. Innes , Cameron‐Christie Sophia , Farthing Sonja , McCall John , Robertson Stephen P. , Wong Hayley , Morreau Philip N.
Published: October 2017

To determine incidence and outcome of biliary atresia (BA) between ethnic groups in New Zealand (NZ), a retrospective review was undertaken of children with BA born between 2002 and 2014. Prioritized ethnicity was used to determine ethnicity and was compared to population data. Uni‐ and multivariate analyses were undertaken to determine demographic and biochemical factors associated with outcome. Overall incidence was 1 in 9181 (Māori 1 in 5285; European 1 in 16,228; P < 0.0001). Overall and transplant‐free survival rates at 1, 2, and 5 years were 92%, 86%, 82% and 70%, 49%, 30% respectively with Māori having improved transplant‐free survival (P < 0.05) despite European children undergoing Kasai earlier (49 vs 63 days). BA is more common in NZ than Europe and North America, which is attributable to a higher incidence in Māori but overall outcome is poorer. Māori have improved transplant‐free survival compared to NZ European children but the reason is unknown.
Reasoning Beyond the Potential Use of Exclusive Enteral Nutrition and Other Specified Diets in Children With Ulcerative Colitis
Authors: Shaoul Ron , Brown Stephanie , Day Andrew S.
Published: October 2017

The incidence of inflammatory bowel disease (IBD) is steadily on the rise in Western and in developing countries paralleling the increase of westernized diets, characterized by high protein and fat as well as excessive sugar intake, with less vegetables and fiber. Furthermore, nutrition is involved in several aspects of pediatric IBD, ranging from disease etiology to induction and maintenance of remission of disease. Exclusive enteral nutrition (EEN) has been shown to induce remission, including in patients with isolated colonic disease, and leads to mucosal healing in Crohn disease. One hypothesis for the beneficial effect of this modality is exclusion of dietary components thought to cause dysbiosis or impair innate immune mechanisms such as the mucous layer, intestinal permeability or colonization and adherence with adherent‐invasive Escherichia coli. Although there is not yet definitive data illustrating a role for EEN in the management of active ulcerative colitis (UC), there are several lines of evidence that illustrate that dietary interventions may be helpful. In particular, the key mechanisms of the activity of EEN (namely, changes in the intestinal microflora in Crohn disease) are likely also relevant to UC. Furthermore, the use of EEN in pediatric UC patients may add to a better bone health. Prospective studies are now required to evaluate the role of EEN in UC in children.
Prevalence and correlations between suicide attempt, depression, substance use, and functionality among patients with limb amputations
Authors: Arias Vázquez Pedro I. , Castillo Avila Rosa G. , Dominguez Zentella Mayra del C. , Hernández-Díaz Yazmín , González-Castro Thelma B. , Tovilla-Zárate Carlos A. , Juárez-Rojop Isela E. , López-Narváez María L. , Frésan Ana
Published: October 2017

Most patients undergoing limb amputations suffer significant emotional changes. The aim of this study was to estimate the prevalence of suicide attempts and depression in a sample of Mexican patients with limb amputations and, second, to determine whether the patients’ functionality correlates with the presence of depression. We studied 40 patients who had undergone a limb amputation. The suicide attempt was evaluated using the Suicide Intent Scale. The depression was assessed using the Hamilton Depression Rating Scale, whereas the functionality of the patients was measured using the Functional Independence Measure. In this sample, 90% were men, whereas only 10% were women. In terms of the suicide behavior, we identified suicide attempts in 27.5% of the patients. The rate of depression was 92.5%. In the Functional Independence Measure, we observed that 57.5% of the patients showed complete dependence. Finally, a significant correlation was found between depression and functionality (r=−0.75, P<0.001). The findings of the present study highlight the high incidence of suicide attempts and depression in Mexican patients with limb amputations. Also, we identified a correlation between the lack of functional independence and depression. Therefore, holistic interventions are necessary in these patients: rehabilitation therapy to increase their functionality, and psychological and pharmacology therapy to decrease suicidal behavior and depression. Finally, more studies using larger samples are necessary to obtain conclusive results.
Memory Guides the Comprehension of Event Changes for Older and Younger Adults
Authors: Wahlheim Christopher N. , Zacks Jeffrey M.
Published: October 2017

Two experiments examined adult age differences in the use of memory to comprehend changes in everyday activities. Participants viewed movies depicting an actor performing activities on two fictive days in her life. Some activities were repeated across days, other activities were repeated with a changed feature (e.g., waking up to analarm clockor aphone alarm), and a final set of activities was performed on Day 2 only. After a one-week delay, participants completed a cued recall test for the activities of Day 2. Unsurprisingly, exact repetition boosted final recall. More surprising, features that changed from Day 1 to Day 2 were remembered approximately as well as features that were only presented on Day 2—showing an absence of proactive interference and in some cases proactivefacilitation. Proactive facilitation was strongly related to participants’ ability to detect and recollect the changes. Younger adults detected and recollected more changes than older adults, which in part explained older adults’ differential deficit in memory for changed activity features. We propose that this pattern may reflect observers’ use of episodic memory to make predictions during the experience of a new activity, and that when predictions fail, this triggers processing that benefits subsequent episodic memory. Disruption of this chain of processing could play a role in age-related episodic memory deficits.
A mathematical and computational model of the calcium dynamics inCaenorhabditis elegansASH sensory neuro
Authors: Mirzakhalili Ehsan , Epureanu Bogdan , Gourgou Eleni
Published: October 2017

We propose a mathematical and computational model that captures the stimulus-generated Ca2+transients in theC. elegansASH sensory neuron. The model is built based on biophysical events and molecular cascades known to unfold as part of neurons’ Ca2+homeostasis mechanism, as well as on Ca2+signaling events. The state of ion channels is described by their probability of being activated or inactivated, and the remaining molecular states are based on biochemically defined kinetic equations with phenomenological adjustments. We estimate the parameters of the model using experimental data of hyperosmotic stimulus-evoked Ca2+transients detected with a FRET sensor in young and aged worms, unstressed and exposed to oxidative stress. We use a hybrid optimization method composed of a multi-objective genetic algorithm and nonlinear least-squares to estimate the model parameters. We first obtain the model parameters for young unstressed worms. Next, we use these values of the parameters as a starting point to identify the model parameters for stressed and aged worms. We show that the model, in combination with experimental data, corroborates literature results. In addition, we demonstrate that our model can be used to predict ASH response to complex combinations of stimulation pulses. The proposed model includes for the first time the ASH Ca2+dynamics observed during both "on" and "off" responses. This mathematical and computational effort is the first to propose a dynamic model of the Ca2+transients’ mechanism inC. elegansneurons, based on biochemical pathways of the cell’s Ca2+homeostasis machinery.

Significance Statement

C. elegansis widely used as a model system for monitoring neuronal Ca2+transients. The ASH neuron is the subject of several such studies, primarily due to its key importance as a polymodal nociceptor. However, despite its pivotal role inC. elegansbiology, and the special characteristics of its stimulus-evoked Ca2+transients (e.g., the "off" response), no mathematical or computational model has been developed to include special features of ASH Ca2+dynamics, i.e. the "off" response. The model includes for the first time the ASH Ca2+dynamics observed during both "on" and "off" responses, and is the first to propose a dynamical model of theC. elegansCa2+transients’ mechanism based on biochemical pathways of the cell’s Ca2+homeostasis machinery.

Abbreviations

ER

endoplasmic reticulum

PMCA

plasma membrane Ca2+ATPase

SERCA

sarco-endoplasmic reticulum Ca2+-transport ATPase

TRPV

transient receptor potential-vallinoid

VGCC

voltage gated Ca2+channels

IP3

3-phopsho inositol

IPR

IP3receptors

ROS

reactive oxygen species

GA

genetic algorithm

ES

extracellular space
Single cell transcriptional profiling reveals cellular diversity, communication, and sexual dimorphism in the mouse heart
Authors: Skelly Daniel A. , Squiers Galen T. , McLellan Micheal A. , Bolisetty Mohan T. , Robson Paul , Rosenthal Nadia A. , Pinto Alexander R.
Published: October 2017

INTRODUCTORY PARAGRAPH

Characterization of the cardiac cellulome—the network of cells that form the heart—is essential for understanding cardiac development and normal organ function, and for formulating precise therapeutic strategies to combat heart disease. Recent studies have challenged assumptions about both the cellular composition1and functional significance of the cardiac non-myocyte cell pool, with unexpected roles identified for resident fibroblasts2and immune cell populations3,4. In this study, we characterized single-cell transcriptional profiles of the murine non-myocyte cardiac cellular landscape using single-cell RNA sequencing (scRNA-Seq). Detailed molecular analyses revealed the diversity of the cardiac cellulome and facilitated the development of novel techniques to isolate understudied cardiac cell populations such as mural cells and glia. Our analyses also revealed networks of intercellular communication as well as extensive sexual dimorphism in gene expression in the heart, most notably demonstrated by the upregulation of immune-sensing and pro-inflammatory genes in male cardiac macrophages. This study offers new insights into the structure and function of the mammalian cardiac cellulome and provides an important resource that will stimulate new studies in cardiac cell biology.
Evaluation of variability in high resolution protein structures by global distance scoring
Authors: Anzai Risa , Asami Yoshiki , Inoue Waka , Ueno Hina , Yamada Koya , Okada Tetsuji
Published: October 2017

Systematic analysis of statistical and dynamical properties of proteins is critical to understanding cellular events. Extraction of biologically relevant information from a set of high-resolution structures is important because it can provide mechanistic details behind the functional properties of protein families, enabling rational comparison between families. Most of the current structure comparisons are pairwise-based, which hampers the global analysis of increasing contents in the Protein Data Bank. Additionally, pairing of protein structures introduces uncertainty with respect to reproducibility because it frequently accompanies other settings for superimposition. This study introduces intramolecular distance scoring, for the analysis of human proteins, for each of which at least several high-resolution are available. We show that the results are comprehensively used to overview advances at the atomic level exploration of each protein and protein family. This method, and the interpretation based on model calculations, provide new criteria for understanding specific and non-specific structure variation in a protein, enabling global comparison of the dynamics among a vast variety of proteins from different species.
Spatially organizing biochemistry: choosing a strategy to translate synthetic biology to the factory
Authors: Jakobson Christopher M. , Tullman-Ercek Danielle , Mangan Niall M.
Published: October 2017

Natural biochemical systems are ubiquitously organized both in space and time. Engineering the spatial organization of biochemistry has emerged as a key theme of synthetic biology, with numerous technologies promising improved biosynthetic pathway performance. One strategy, however, may produce disparate results for different biosynthetic pathways. We propose a spatially resolved kinetic model to explore this fundamental design choice in systems and synthetic biology. We predict that two example biosynthetic pathways have distinct optimal organization strategies that vary based on pathway-dependent and cell-extrinsic factors. Moreover, we outline this design space in general as a function of kinetic and biophysical properties, as well as culture conditions. Our results suggest that organizing biosynthesis has the potential to substantially improve performance, but that choosing the appropriate strategy is key. The flexible mathematical framework we propose can be adapted to diverse biosynthetic pathways, and lays a foundation to rationally choose organization strategies for biosynthesis.
Identification of potential blood-derived extracellular vesicles biomarkers to diagnose and predict distant metastases in ER+ breast cancer patients
Authors: Hamidi Zia , Tejero Eduardo , Schmidt Ronny , Tucker Rod , Pedro Ana
Published: October 2017

Abstract

The objective of this study was to identify potential extracellular vesicles (EV) which might serve as biomarkers for predictive and diagnostic purposes in metastatic breast cancer. Plasma samples from 7 different metastatic and non-metastatic ER+ (estrogen receptor -positive) breast cancer patients were collected, EV were isolated and their protein content analyzed by mass spectrometry and FunRich analysis. In this study we found several putative plasma EV biomarkers for metastatic ER+ breast cancer prediction and diagnosis, such as serum amyloid A1, known to promote widespread metastasis in a breast cancer animal model.
The language of music: Common neural codes for structured sequences in music and natural language
Authors: Chiang Jeffrey N. , Rosenberg Matthew H. , Bufford Carolyn A. , Stephens Daniel , Lysy Antonio , Monti Martin M.
Published: October 2017

The ability to process structured sequences is a central feature of natural language but also characterizes many other domains of human cognition. In this fMRI study, we measured brain metabolic response in musicians as they generated structured and non-structured sequences in language and music. We employed a univariate and multivariate cross-classification approach to provide evidence that a common neural code underlies the production of structured sequences across the two domains. Crucially, the common substrate includes Broca’s area, a region well known for processing structured sequences in language. These findings have several implications. First, they directly support the hypothesis that language and music share syntactic integration mechanisms. Second, they show that Broca’s area is capable of operating supramodally across these two domains. Finally, these results dismiss the recent hypothesis that domain general processes or proximal neural substrates explain the previously observed “overlap” between neuroimaging activations across the two domains.
Control of Mast Cell Regulated Exocytosis by Munc13 Proteins
Authors: Rodarte Elsa M. , Ramos Marco A. , Davalos Alfredo J. , Moreira Daniel C. , Moreno David S. , Cardenas Eduardo I. , Rodarte Alejandro I. , Petrova Youlia , Molina Sofia , Rendon Luis E. , Sanchez Elizabeth , Breaux Keegan , Tortoriello Alejandro , Manllo John , Gonzalez Erika A. , Tuvim Michael J. , Dickey Burton F. , Burns Alan R. , Heidelberger Ruth , Adachi Roberto
Published: October 2017

Mast cells (MCs) are involved in pathogen defense and inflammatory reactions. Upon stimulation, they release substances stored in their granules via regulated exocytosis. In other cell types, Munc13 proteins play essential roles in regulated exocytosis. We found that MCs express Munc13-2 and -4, and we studied their roles using global and conditional knockout (KO) mice. In a model of systemic anaphylaxis, we found no difference between WT and Munc13-2 KO mice, but global and MC-specific Munc13-4 KO mice developed less hypothermia. This protection correlated with lower plasma histamine levels and histological evidence of defective MC degranulation, and not with changes in MC development, distribution, numbers or morphology. In vitro assays revealed that the defective MC response in the absence of Munc13-4 was limited to regulated exocytosis, leaving other MC secretory effector responses intact. Single cell capacitance measurements in MCs from mouse mutants with different expression levels of Munc13-4 in their MCs showed that as levels of Munc13-4 decrease, the rate of exocytosis declines first, and the total amount of exocytosis follows. A requirement for Munc13-2 in MC exocytosis was revealed only in the absence of Munc13-4. Electrophysiology and electron microscopy studies showed that the number of multigranular compound events (granule-to-granule homotypic fusion) was severely reduced in the absence of Munc13-4. We conclude that while Munc13-2 plays a minor role, Munc13-4 is essential for regulated exocytosis in MCs, and that this MC effector response is required for a full IgE-mediated anaphylactic response.
Refraction and ultra-small-angle scattering of X-rays in a single-crystal diamond compound refractive lens
Authors: Gasilov S. , Mittone A. , dos Santos Rolo T. , Polyakov S. , Zholudev S. , Terentyev S. , Blank V. , Bravin A. , Baumbach T.
Published: October 2017

In this work a double-crystal setup is employed to study compound refractive lenses made of single-crystal diamond. The point spread function of the lens is calculated taking into account the lens transmission, the wavefront aberrations, and the ultra-small-angle broadening of the X-ray beam. It is shown that, similarly to the wavefront aberrations, the ultra-small-angle scattering effects can significantly reduce the intensity gain and increase the focal spot size. The suggested approach can be particularly useful for the characterization of refractive X-ray lenses composed of many tens of unit lenses.
Hit detection in serial femtosecond crystallography using X-ray spectroscopy of plasma emission
Authors: Jönsson H. Olof , Caleman Carl , Andreasson Jakob , Tîmneanu Nicuşor
Published: October 2017

Serial femtosecond crystallography is an emerging and promising method for determining protein structures, making use of the ultrafast and bright X-ray pulses from X-ray free-electron lasers. The upcoming X-ray laser sources will produce well above 1000 pulses per second and will pose a new challenge: how to quickly determine successful crystal hits and avoid a high-rate data deluge. Proposed here is a hit-finding scheme based on detecting photons from plasma emission after the sample has been intercepted by the X-ray laser. Plasma emission spectra are simulated for systems exposed to high-intensity femtosecond pulses, for both protein crystals and the liquid carrier systems that are used for sample delivery. The thermal radiation from the glowing plasma gives a strong background in the XUV region that depends on the intensity of the pulse, around the emission lines from light elements (carbon, nitrogen, oxygen). Sample hits can be reliably distinguished from the carrier liquid based on the characteristic emission lines from heavier elements present only in the sample, such as sulfur. For buffer systems with sulfur present, selenomethionine substitution is suggested, where the selenium emission lines could be used both as an indication of a hit and as an aid in phasing and structural reconstruction of the protein.
Copper(II)- and gold(III)-mediated cyclization of a thiourea to a substituted 2-aminobenzothiazole
Authors: Schroeder Zachary W. , Hiscock L. K. , Dawe Louise Nicole
Published: October 2017

Benzothiazole derivatives are a class of privileged molecules due to their biological activity and pharmaceutical applications. One route to these molecules is via intramolecular cyclization of thioureas to form substituted 2-aminobenzothiazoles, but this often requires harsh conditions or employs expensive metal catalysts. Herein, the copper(II)- and gold(III)-mediated cyclizations of thioureas to substituted 2-aminobenzothiazoles are reported. The single-crystal X-ray structures of the thiourea N-(3-methoxyphenyl)-N′-(pyridin-2-yl)thiourea, C13H13N3OS, and the intermediate metal complexes aquabis[5-methoxy-N-(pyridin-2-yl-κN)-1,3-benzothiazol-2-amine-κN
3]copper(II) dinitrate, [Cu(C13H11N3OS)2(H2O)](NO3)2, and bis{2-[(5-methoxy-1,3-benzothiazol-2-yl)amino]pyridin-1-ium} dichloridogold(I) chloride monohydrate, (C13H12N3OS)2[AuCl2]Cl·H2O, are reported. The copper complex exhibits a distorted trigonal–bipyramidal geometry, with direct metal-to-benzothiazole-ligand coordination, while the gold complex is a salt containing the protonated uncoordinated benzothiazole, and offers evidence that metal reduction (in this case, AuIII to AuI) is required for the cyclization to proceed. As such, this study provides further mechanistic insight into the role of the metal cations in these transformations.
Green synthesis and crystal structure of 3-(benzothiazol-2-yl)thiophene
Authors: Nguyen Ngoc Linh , Vu Quoc Trung , Duong Quoc Hoan , Vu Quoc Manh , Truong Minh Luong , Thang Pham Chien , Van Meervelt Luc
Published: October 2017

The title compound, C11H7NS2, was prepared in high yield (87%) using a solvent-free microwave-assisted synthesis. The structure shows whole-molecule disorder with occupancies for two orientations (A and B) of 0.4884 (10) and 0.5116 (10), respectively. The thiophene and benzothiazole rings are almost planar and make dihedral angles of 10.02 (18) and 12.54 (19)° for orientations A and B, respectively. Slipped π–π stacking between the aromatic rings, together with C—H...π, C—H...S and C—H...N interactions, result in a herringbone motif in the crystal packing.
Taguchi-based combined grey relational and principal component analyses for multi-response optimization of diesel engines
Authors: Muqeem Mohd , Sherwani Ahmad Faizan , Ahmad Mukhtar , Khan Zahid Akhtar
Published: October 2017

Purpose

Diesel engine can produce power more efficiently with lower exhaust emissions when operated at optimum input parameter settings. To achieve this goal, the purpose of this paper is to optimize the input parameters of diesel engine which will lead to optimum performance and exhaust emissions.

Design/methodology/approach

To achieve the goal of improving diesel engine performance and exhaust emissions, four input parameters were considered in the study. Five different levels of each input parameter were taken. Four response variables under no load, half load and full load conditions were recorded. Experiments were performed in random manner according to selected Taguchi L25 orthogonal array. The data were analyzed using grey relational analysis coupled with principal component analysis. Analysis of S/N ratio was performed to obtain the optimum combination of input parameters. The grey relational grade at optimum setting of the input parameters was obtained by regression analysis.

Findings

Results of the current research work give the optimum input parameter settings for no load, half load and full load conditions of diesel engine. Engine produces power more efficiently with low exhaust emissions when operated at these optimum settings.

Practical implications

In view of the compliance to the stringent air pollution norms of the nations and fast depleting fossil fuels, it is of the utmost importance to design and operate the engine in the optimum range of its input parameters so that it produces more power with low exhaust emissions. This paper aims at optimizing input parameters of diesel engine to improve performance and exhaust emissions. Results of the study presented in this paper are significantly useful for diesel engine-related researchers and professionals.

Originality/value

From the literature review, it appears that only few researchers have conducted studies pertaining to the optimization of the input parameters of diesel engine to improve performance or exhaust emissions. Although few studies related to the optimization of compression ratio, fuel injection timing, fuel injection pressure and air pressure have been reported, no work related to optimization of temperature and pressure of turbocharged air has been reported. Therefore, the main focus of the current research work is on optimizing the charge air temperature and pressure with respect to performance and exhaust emissions.
Study of a discrete grey forecasting model based on the quality cost characteristic curve
Authors: Dong Wenjie , Liu Sifeng , Fang Zhigeng , Yang Xiaoyu , Hu Qian , Tao Liangyan
Published: October 2017

Purpose

The purpose of this paper is to clarify several commonly used quality cost models based on Juran’s characteristic curve. Through mathematical deduction, the lowest point of quality cost and the lowest level of quality level (often depicted by qualification rate) can be obtained. This paper also aims to introduce a new prediction model, namely discrete grey model (DGM), to forecast the changing trend of quality cost.

Design/methodology/approach

This paper comes to the conclusion by means of mathematical deduction. To make it more clear, the authors get the lowest quality level and the lowest quality cost by taking the derivative of the equation of quality cost and quality level. By introducing the weakening buffer operator, the authors can significantly improve the prediction accuracy of DGM.

Findings

This paper demonstrates that DGM can be used to forecast quality cost based on Juran’s cost characteristic curve, especially when the authors do not have much information or the sample capacity is rather small. When operated by practical weakening buffer operator, the randomness of time series can be obviously weakened and the prediction accuracy can be significantly improved.

Practical implications

This paper uses a real case from a literature to verify the validity of discrete grey forecasting model, getting the conclusion that there is a certain degree of feasibility and rationality of DGM to forecast the variation tendency of quality cost.

Originality/value

This paper perfects the theory of quality cost based on Juran’s characteristic curve and expands the scope of application of grey system theory.
Study on distance measuring and sorting method of general grey number
Authors: Jiang Shi-quan , Liu Si-feng , Fang Zhi-geng , Liu Zhong-xia
Published: October 2017

Purpose

The purpose of this paper is to study distance measuring and sorting method of general grey number.

Design/methodology/approach

First, the concept of generalised grey number based on grey system theory is given in this paper. Second, from the perspective of kernel and degree of greyness of general grey number, the method of measuring the distance of general grey number and its properties are given. At the same time, the concepts of the kernel expectation and the kernel variance of the general grey number are proposed.

Findings

Up to now, the method of measuring the distance and sorting of general grey number is established. Thus, the difficult problem for set up sorting of general grey number has been solved to a certain degree.

Research limitations/implications

The method exposed in this paper can be used to integrate information form a different source. Distance measuring and sorting method of general grey number could be extended to the case of grey algebraic equation, grey differential equation and grey matrix which includes general grey numbers, etc.

Originality/value

The concepts of the kernel expectation and the kernel variance of the general grey number are proposed for the first time in this paper; the novel sorting rules of general grey numbers were also constructed.
The multiple attribute decision model of grey targets based on grey potential degree
Authors: Ruan Aiqing , Wang Yinao
Published: October 2017

Purpose

Grey target decision making is one of the important problems of decision-making theory. It is critical to express uncertain information effectively and depose them in a reasonable and simple way. The purpose of this paper is to solve the grey target problem by the grey potential degree method without whiten value and without distribution function. Furthermore, this new approach has an advantage of realizing both comparing and standardization work during the process of treating the data.

Design/methodology/approach

First, this paper makes a brief overview of the existing method for grey target decision. Then, the conception of a grey potential degree system is introduced and the conception of standard grey potential degree is build up, and a new grey potential-based method based on the grey target multiple attribute decision method is proposed. At the same time, the standard grey potential and its application in multiple resource data are studied.

Findings

At the same time the standard grey potential and its application in multiple resource data are studied. Standard grey potential is presented by means of three examples together with the comparison with the existing method to demonstrate that the grey potential-based method could be used to solve the problem of grey target decision conveniently and effectively.

Originality/value

It is very important to compare grey numbers to obtain scientific and reasonable results for a grey target decision-making problem. However, in the actual application of grey numbers, it is difficult to find out the probability density function or the whiten function of grey numbers. When grey numbers are compared and deposed through the whiten value, much information regarding grey numbers will be lost and, at the same time, the value of grey numbers in uncertainty is partly lost. The method discussed in this paper is reasonable and feasible.
Why teachers and students stay home
Authors: Bristol Travis J.
Published: October 2017

Purpose

The purpose of this paper is to explore the influences of teacher and student absenteeism across nine public schools (five primary and four secondary) in Guyana, South America.

Design/methodology/approach

To conduct this study, the author employed a mixed-methods study that included a descriptive analysis of a purposive sample of teacher (n=69) and student (n=175) surveys and semi-structured interviews with head teachers (n=8), teachers (n=25), students (n=36), and parents (n=9).

Findings

The findings suggested that teacher absenteeism can be attributed to school organizational challenges, such as poor working conditions and weak administrative leadership. Student absenteeism appeared to be influenced primarily by out-of-school factors such as the need to work and to take care of younger siblings.

Research limitations/implications

The study’s purposive sample may have prevented a more nuanced understanding of the various influences of teacher and student absenteeism.

Originality/value

The author provides new insight into some of the root influences of teacher and student absenteeism in Guyana, South America. As such, policymakers and practitioners in the Ministry of Education are positioned to devise evidence-based solutions.
Optimization of hybrid aluminum composites wear using Taguchi method and artificial neural network
Authors: Stojanovic Blaza , Blagojevic Jasmina , Babic Miroslav , Velickovic Sandra , Miladinovic Slavica
Published: October 2017

Purpose

This research aims to describe the influence of weight per cent of graphite (Gr), applied load and sliding speed on the wear behavior of aluminum (Al) alloy A356 reinforced with silicon carbide (SiC) (10 Wt.%) and Gr (1 Wt.% and 5 Wt.%) particles. The objective is to analyze the effect of the aforementioned parameters on a specific wear rate.

Design/methodology/approach

These hybrid composites are obtained by means of the compo-casting process. Tribological analyses were conducted on block-on-disc tribometer at three different loads (10, 20 and 30 N) and three different sliding speeds (0.25, 0.5 and 1 m/s), at the sliding distance of 900 m, in dry sliding wear conditions. Optimization of the tribological behavior was conducted via the Taguchi method, and ANOVA was used for the analysis of the specific wear rate. Confirmation tests are used to foresee and check the experimental results. Examined samples were analyzed via a scanning electron microscope (SEM). Regression models for predicting specific wear rate were developed with Taguchi and ANN (artificial neural network) methods.

Findings

The biggest impact on value of specific wear rate has the load (43.006%), while the impact of Wt.% Gr (31.514%) was less. After comparison of the results, i.e. regression models, for predicting the specific wear rate, it was observed that ANN was more efficient than the Taguchi method. The specific wear rate of Al alloy A356 with SiC (10 Wt.%) and Gr (1 Wt.% and 5 Wt.%) decreases with a decrease in the load and weight per cent of Gr-reinforcing material, as well as with a decrease in sliding speed.

Originality/value

The results obtained in this paper using the Taguchi method and the ANN method are useful for improving and further investigating the wear behavior of the SiC- and Gr-reinforced Al alloy A356.
Low friction of phytic acid as a water-based lubricant additive
Authors: Wan Yong , Yu Yankun , Gao Shuai , Gao Jianguo
Published: October 2017

Purpose

The purpose of this paper is to evaluate naturally occurring phytic acid (PA) as a green-water-based lubricant.

Design/methodology/approach

Lubrication is studied using a ball-on-disk tribometer with silica glass against silicon nitride contact, and the friction coefficient and wear are measured in the boundary lubrication regimes.

Findings

Excellent lubrication performance was found by using PA aqueous solutions. After the running-in process, the sliding coefficient of friction could drop to as low as 0.01 with a quite low concentration of 7.5 × 10−4 M. The lubricating performance of PA solution could be further improved by increasing PA concentration. The work suggests that the excellent lubricity of PA in aqueous solution can be mostly contributed to its adsorption on the silica surface.

Originality/value

The paper shows that the natural products could be used as water-based lubricant additives.
Behaviour of two-lobe hole-entry hybrid journal bearing system under the combined influence of textured surface and micropolar lubricant
Authors: Khatri Chandra B. , Sharma Satish C.
Published: October 2017

Purpose

The aim of the present paper is to study the combined influence of textured surface and micropolar lubricant behaviour on the performance of two-lobe hole-entry hybrid journal bearing system. The bearing performance parameters of the textured circular/two-lobe hole-entry hybrid journal bearing system have been computed against the constant vertical external load supported by the bearing.

Design/methodology/approach

In this work, Eringen’s micropolar fluid theory has been used to derive the governing Reynolds equation. The consequent solution of the governing Reynolds equation has been obtained by using finite element method (FEM) numerical technique.

Findings

The present study indicates that the use of the textured surface, two-lobe profile of bearing and micropolar lubricant, significantly enhances the bearing performance as compared to non-textured circular journal bearing.

Originality/value

The present study concerning the influence of surface texturing on the behaviour of the two-lobe hole-entry hybrid journal bearing lubricated with micropolar lubricant is original. The theoretically simulated results of the present study will be useful to design an efficient journal bearing system.
Effect of chromium content on cementite – pearlite interaction of white cast iron during three-body abrasive wear
Authors: Zheng Baochao , Huang Zhifu , Xing Jiandong , Xiao Yiyang , Xiao Fan
Published: October 2017

Purpose

This paper aims to demonstrate the effect of varying chromium content on the wear behavior of white cast iron, to study the interaction relationship between cementite and pearlite in white cast iron, while estimating their contribution rate in abrasive wear.

Design/methodology/approach

To study interaction of cementite-pearlite of white cast irons with different chromium content in three-body abrasive wear, three kinds of chromium white cast iron, bulk single-phase cementite, pure pearlite samples and the white cast iron (WCI), were prepared using the melting and casting technique. The so-called pure pearlite samples have the same chemical composition, microstructure and properties as the pearlite matrix in white cast iron.

Findings

Results indicated that the interaction has a negative value. Its absolute value decreased with increasing chromium addition. Meanwhile, a high load resulted in an increased interaction value. The contribution rate of cementite to interaction, which was higher than that of pearlite, increased with increasing chromium addition. This indicated cementite was a main phase. Besides, the reductive size of abrasive has a significant effect on the contribution rate at the high load. These prominent cementite occurred fracture, when small size abrasive indented the matrix. These result in the absence of a protective effect of cementite during wear process. Eventually, the contribution rate of cementite decreased significantly.

Originality/value

This paper demonstrates the effect of varying chromium content on wear behavior of white cast iron, to study the interaction relationship between cementite and pearlite in white cast iron while estimating their contribution rate in abrasive wear.
Tribological properties of hydrogen free DLC in self-mated contacts against ZDDP-added oil
Authors: Mannan Abdul , Mohd Sabri Mohd Faizul , Kalam M.A. , Masjuki H.H.
Published: October 2017

Purpose

The purpose of this study is to investigate the tribological properties of tetrahedral diamond-like carbon (DLC) films in self-mated contacts in the presence of additivated and non-additivated vegetable oils. DLC films have high practical value due to low friction and low wear properties. On the other hand, vegetable oils are considered to be lubricants for future due to its resource renewability and biodegradability. Sometimes different chemical agents are added to vegetable oils to further improve its tribological properties. Thus, the tribological study of DLC films against additivated oils becomes important.

Design/methodology/approach

The tribology tests were conducted in a four ball tribo-meter under the boundary lubricated conditions.

Findings

Ta-C DLC exhibited 80 per cent lower wear rate under Zinc dialkyldithiophosphates (ZDDP)-added oil compared to that of base oil. In contrast, the friction coefficient under additivated oil was slightly higher than the base oil lubricated case. Moreover, the carbonyl band area as well as the viscosity change of ZDDP-added oil was much smaller than that of base oil. Therefore, ZDDP reduced the wear of DLC film and prevented the oxidation of base oil during tribotests.

Originality/value

This is the first work on the tribological properties of ta-C DLC lubricated with corn oil with and without anti-wear additives.
Feature extraction of rolling bearing fault signal based on local mean decomposition and Teager energy operator
Authors: Cai Jianhua
Published: October 2017

Purpose

This paper aims to explore a new way to extract the fault feature of a rolling bearing signal on the basis of a combinatorial method.

Design/methodology/approach

By combining local mean decomposition (LMD) with Teager energy operator, a new feature-extraction method of a rolling bearing fault signal was proposed, called the LMD–Teager transform method. The principles and steps of method are presented, and the physical meaning of the time–frequency power spectrum and marginal spectrum is discussed. On the basis of comparison with the fast Fourier transform method, a simulated non-stationary signal was processed to verify the effect of the new method. Meanwhile, an analysis was conducted by using the recorded vibration signals which include inner race, out race and bearing ball fault signal.

Findings

The results show that the proposed method is more suitable for the non-stationary fault signal because the LMD–Teager transform method breaks through the difficulty of the Fourier transform method that can process only the stationary signal. The new method can extract more useful information and can provide better analysis accuracy and resolution compared with the traditional Fourier method.

Originality/value

Combining the advantage of the local mean decomposition and the Teager energy operator, the LMD–Teager method suits the nature of the fault signal. A marginal spectrum obtained from the LMD–Teager method minimizes the estimation bias brought about by the non-stationarity of the fault signal. So, the LMD–Teager transform has better analysis accuracy and resolution than the traditional Fourier method, which provides a good alternative for fault diagnosis of the rolling bearing.
Fabrication of Al/Babbitt surface bearing through friction stir processing
Authors: Arab Seyed Mohammad , Hosseini Zeidabadi Seyed Reza , Jenabali Jahromi Seyed Ahmad , Daneshmanesh Habib , Zebarjad Seyed Mojtaba , Janghorban Kamal
Published: October 2017

Purpose

A self-lubricant surface composite including Al matrix and Babbitt alloy 11 reinforcement has been fabricated via friction stir processing (FSP).

Design/methodology/approach

The optimum processing condition is estimated by statistical analysis of a L9 Taguchi design of experiment. The results of Taguchi analysis suggested four passes of FSP, traverse speed of 40 mm/min and rotational speeds of 1,250 rpm as the optimum parameters to achieve higher hardness and wear resistance.

Findings

The needle-shaped particles are fragmented into the finer particles after FSP. There is uniform distribution of precipitations after FSP. The microhardness of manufactured surface bearings has been increased. Finer particles, smaller grains and in situ formed intermetallic precipitations (AlSb) can be responsible for hardness enhancement. Wear resistance of base metal also has been remarkably enhanced after FSP.

Originality/value

The originality of this paper lies in the following: new self-lubricating surface composite; a tough and resistant to wear sheets; and using a solid-state method to fabricate a surface bearing.
Freight group behavior under freight traffic restriction policy
Authors: Yang Haoxiong , Sun Lijun , Lan Shulin , Yang Chen
Published: October 2017

Purpose

Many cities implement freight traffic restriction policy (FTRP) intending to reduce traffic congestion and air pollution. At the same time, city distribution had some negative effects. The purpose of this paper is therefore to study the freight group behavior under FTRP, and to provide some recommendations for the government.

Design/methodology/approach

This paper establishes a city distribution system model built by a simulation method of Agent, which includes the complex adaptability of freight individual, event of restriction policy, the influence factor of freight group behavior and its changes from the perspective of restriction policy. The rules of microscopic freight group behavior to macroscopic freight group behavior, the effects on freight group behavior exerted by restriction policy and the dynamic mechanism of freight group behavior are all studied. The model is also simulated with the traffic data of Beijing in China.

Findings

Theoretical results ensure that restriction of the passport is not the sole reason that may produce illegal trucks, and other measures need to be taken to solve the traffic problems. And in the long run, increasing fines has a greater effect than strengthening supervision frequency on illegal trucks reduction.

Originality/value

From city distribution perspective, this paper studied freight group behavior under FTRP. This paper also applied the Agent modeling method to build a model of urban distribution system in the FTRP.