bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of geometrical defects caused by thermal distortions in laser-beam-melting additive manufacturing: a simulation approach
Authors: Douellou Corentin , Balandraud Xavier , Duc Emmanuel 
Published: August 2019

Purpose
The purpose of this paper is to develop a numerical approach inspired by Geometrical Product Specifications (GPS) standards for the assessment of geometrical defects appearing during Additive Manufacturing (AM) by Laser Beam Melting (LBM).

Design/methodology/approach
The study is based on finite element (FE) simulations of thermal distortions, then an assessment of flatness defects (warping induced by the high-residual stresses appearing during the manufacturing) from the deformed surfaces provided by simulation, and finally the correction of the calculated flatness defects from preliminary comparison between simulated and experimental data.

Findings
For an elementary geometrical feature (a wall), it was possible to identify the variation in the flatness defect as a function of the dimensions. For a complex geometry exhibiting a significant flatness defect, it was possible to improve the geometric quality using the numerical tool.

Research limitations/implications
To the best of the author’s knowledge, this work is the first attempt using a numerical approach inspired by GPS standards to identify variations in thermal distortions caused by LBM, which is an initial step toward optimization. This paper is mainly focused on flatness defect assessment, even though the approach is potentially applicable for all types of geometrical defects (shape, orientation or position defects).

Practical implications
The study opens prospects for the optimization of complex parts elaborated using LBM, based on the minimization of the geometric defects caused by thermal distortions.

Social implications
The prospects in terms of shape optimization will extend the potential to benefit from the new possibilities offered by LBM additive manufacturing.

Originality/value
Unlike the usual approach, the proposed methodology does not require any artifacts or comparisons with the computer-aided-design (CAD) model for geometrical distortion assessment. The present approach opens up the possibility of performing metrology from FE simulation results, which is particularly promising in the AM field.
Insights into fabrication mechanism of pure copper thin wall components by selective infrared laser melting
Authors: Guan Jieren , Zhang Xiaowei , Jiang Yehua , Yan Yongnian 
Published: August 2019

Purpose
This study aims to obtain the mechanistic insights for the fabrication of pure copper thin wall components by selective infrared (IR) laser melting (SLM) and correlated with microstructure development, microhardness, surface morphology and phase analysis. Experimental processes for single track and selection of substrate materials have been studied using a combination of different laser powers and scanning speeds.

Design/methodology/approach
SLM of pure copper was performed on a YONGNIAN Laser YLMS-120 SLM machine using an Nd: YAG fiber laser operating at 1,060 nm in the NIR region. Single-track experiments and processing parameters are investigated through different combinations of laser power and scanning speed. The microstructure of the fabricated pure copper samples by SLM technique was analyzed by means of X-ray diffraction, scanning electron microscope equipped with energy disperse spectrometer, optical microscope (OM) and micro-hardness tester.

Findings
Steel-based substrates were found suitable for pure copper manufacturing due to sufficient heat accumulation. The width of a single track was determined by liner energy density, showing discontinuities and irregular morphologies at low laser powers and high scanning speeds. As a result of instability of the molten pool induced by Marangoni convection, cracks and cavities were observed to appear along grain boundaries in the microstructure. The top surface morphology of SLM-processed component showed a streamflow structure and irregular shapes. However, the powder particles attached to side surface, which manifest copper powders, are even more sensitive to melt pool of contour track. The crystal phase characteristics of copper components indicated increasing crystallite size of a-Cu, and the decreasing intensity of diffraction peak was attributed to the presence of defects during SLM. The maximum relative density and microhardness were 82 per cent and 61.48 HV0.2, respectively. The minimum thickness of a pure copper thin wall component was 0.2 mm.

Originality/value
This paper demonstrated the forming mechanism and explored feasibility of pure copper thin wall parts by SLM technology in the NIR region. The surface morphology, microstructure and crystal structure were preliminary studied with laser processing parameters.
Effect of multiple laser peening on surface integrity and microstructure of laser additive manufactured Ti6Al4V titanium alloy
Authors: Hu Yongxiang , Lai Mengqi , Hu Zonghao , Yao Zhenqiang 
Published: August 2019

Purpose
Laser additive manufacturing is widely utilized to fabricate the Ti6Al4V alloy, but it requires post-processing to improve its performance. This paper aims to propose laser peening (LP) as an effective way to improve the surface characteristics of the Ti6Al4V alloy fabricated by direct laser deposition (DLD).

Design/methodology/approach
Surface integrity including surface roughness, porosity, residual stress and microhardness are investigated in detail before and after LP treatment. Microstructure evolution is characterized by the electron backscatter diffraction (EBSD) to analyze crystal phase, grain boundary misorientation and texture.

Findings
Multiple overlapping layers of LP treatment result in slight influence on the polished surface of DLD-built samples. Porosity measured by the Archimedes test is found to be greatly decreased after LP treatment. Compressive residual stresses are significantly induced, the magnitude of which is greatly increased by increasing layers of LP treatment. And, local weakening or enhancement of residual stress in depth is observed because of pore and inclusion defects in the DLD-built Ti6Al4V alloy. Favorable hardness property can be obtained after multiple overlapping layers of LP treatment. EBSD analysis shows that LP treatment with multiple layers can introduce a large amount of lower-angle boundaries, indicating that dislocations beneath the top surface could induce a strain-hardened layer. The microtexture of the DLD-built Ti6Al4V alloy cannot be eliminated to decrease the anisotropy of the mechanical property.

Research limitations/implications
The variation of porosity observed after LP inside the DLD-built Ti-Al-4V is attractive but requires more detailed work to analyze the evolution of pore geometry.

Practical implications
Surface treatment of an additive manufactured titanium alloy was carried out to improve its fatigue resistance.

Originality/value
This work is original in proposing LP as an effective post process for the surface treatment of an additive manufactured titanium alloy through analyzing the surface integrity and microstructure evolution.
Coupling control of pore size and spatial distribution in bone scaffolds based on a random strategy for additive manufacturing
Authors: Li Jingrong , Xu Zhijia , Wang Qinghui , Hu Guanghua , Wang Yingjun 
Published: August 2019

Purpose
The three-dimensional porous scaffold is an important concept in tissue engineering and helps to restore or regenerate a damaged tissue. Additive manufacturing (AM) technology makes the production of custom-designed scaffolds possible. However, modeling scaffolds with intricate architecture and customized pore size and spatial distribution presents a challenge. This paper aims to achieve coupling control of pore size and spatial distribution in bone scaffolds for AM.

Design/methodology/approach
First, the proposed method assumes that pore size and spatial distribution have already been transformed from the requirements of scaffolds as inputs. Second, the structural characteristics of scaffolds are explicitly correlated with an all-hexahedron meshing method for scaffold design so that the average pore size could be controlled. Third, the highly coupled internal mesh vertices are adjusted based on a random strategy so that the pore size and spatial distribution conform to their respective desired values. Fourth, after the adjustment, the unit pore cell based on a triply periodic minimal surface was mapped into the hexahedrons through a shape function, thereby ensuring the interconnectivity of the porous scaffold.

Findings
The case studies of three bone scaffolds demonstrate that the proposed approach is feasible and effective to simultaneously control pore size and spatial distribution in porous scaffolds.

Practical implications
The proposed method may make it more flexible to design scaffolds with controllable internal pore architecture for AM.

Originality/value
In the control approach, the highly coupled mesh vertices are adjusted through a random strategy, which can determine the moving direction and range of a vertex dynamically and biasedly, thus ensuring the feasibility and efficiency of the proposed method.
“I am not getting your money”: boundary making and identities in immigrant economies in Hong Kong
Authors: Kwok K. 
Published: August 2019

Purpose
This paper aims to explore how immigrant small business owners construct entrepreneurial identities by deploying strategies of boundary making in Hong Kong.

Design/methodology/approach
Conceptually, it departs from the theoretical discussions of immigrant economy and ethnic boundary making. The analyzes are based on qualitative data collected from in-depth interviews and participant observation primarily in the South Asian immigrant economies in Hong Kong in the period 2014-2017.

Findings
Four strategies of boundary work including blurring boundaries, inversion of boundaries, personal repositioning and reconfirming of boundaries are identified. They bring to light that small immigrant entrepreneurs in Hong Kong still encounter considerable obstacles in the process of social integration. Boundary work serves as strategies to release sentiments that would symbolically bring them closer to the mainstream society. Following the “city as context” framework (Brettell, 1999; Foner, 2007), this paper argues that the various boundary making strategies have been shaped by the legacies of racism, neoliberal governance of integration and urban work ethos highlighting problems and individual responsibilities in Hong Kong.

Originality/value
This paper contributes to the literature of the immigrant economy and social integration. First, it sheds light on the role of symbolic meanings and non-economic gains of immigrant entrepreneurship in social integration. Second, it illuminates our understanding that immigrant economy can provide a channel for advancing and weakening social status, thus reminding us not to assume the path of social integration as a straightforward and positive one.
Gene pool transmission of multidrug resistance among Campylobacter from livestock, sewage and human disease
Authors: Mourkas Evangelos , Florez‐Cuadrado Diego , Pascoe Ben , Calland Jessica K. , Bayliss Sion C. , Mageiros Leonardos , Méric Guillaume , Hitchings Matthew D. , Quesada Alberto , Porrero Concepción , Ugarte‐Ruiz María , Gutiérrez‐Fernández José , Domínguez Lucas , Sheppard Samuel K. 
Published: August 2019

SummaryThe use of antimicrobials in human and veterinary medicine has coincided with a rise in antimicrobial resistance (AMR) in the food‐borne pathogens Campylobacter jejuni and Campylobacter coli. Faecal contamination from the main reservoir hosts (livestock, especially poultry) is the principal route of human infection but little is known about the spread of AMR among source and sink populations. In particular, questions remain about how Campylobacter resistomes interact between species and hosts, and the potential role of sewage as a conduit for the spread of AMR. Here, we investigate the genomic variation associated with AMR in 168 C. jejuni and 92 C. coli strains isolated from humans, livestock and urban effluents in Spain. AMR was tested in vitro and isolate genomes were sequenced and screened for putative AMR genes and alleles. Genes associated with resistance to multiple drug classes were observed in both species and were commonly present in multidrug‐resistant genomic islands (GIs), often located on plasmids or mobile elements. In many cases, these loci had alleles that were shared among C. jejuni and C. coli consistent with horizontal transfer. Our results suggest that specific antibiotic resistance genes have spread among Campylobacter isolated from humans, animals and the environment.
Amygdala Arginine Vasopressin Modulates Chronic Ethanol Withdrawal Anxiety‐Like Behavior in the Social Interaction Task
Authors: Harper Kathryn M. , Knapp Darin J. , Butler Ryan K. , Cook Cory A. , Criswell Hugh E. , Stuber Garret D. , Breese George R. 
Published: August 2019

BackgroundChronic ethanol (EtOH) exposure induces neurobehavioral maladaptations in the brain though the precise changes have not been fully explored. The central nucleus of the amygdala (CEA) regulates anxiety‐like behavior induced by withdrawal from chronic intermittent EtOH (CIE) exposure, and the arginine vasopressin (AVP) system within the CEA regulates many anxiety‐like behaviors. Thus, adaptations occur in the CEA AVP system due to chronic EtOH exposure, which lead to anxiety‐like behaviors in rats.MethodsChronic exposure to a low‐dose EtOH (4.5% wt/vol) induces anxiety‐like behavior in rats. Wistar or Sprague Dawley rats were exposed to a modified CIE or CIE, while intra‐CEA microinjections of AVP or a V1b receptor antagonist were used to elicit or block withdrawal‐induced anxiety. Additionally, AVP microinjections into the CEA were given 24 hours following 15 days of continuous high‐dose EtOH (7% wt/vol), a time period when rats no longer express anxiety. Chemogenetics was also used to activate the basolateral amygdala (BLA) or deactivate the dorsal periaqueductal gray=(dm/dlPAG) therefore PAG=periaqueductal gray to elicit or block withdrawal‐induced anxiety.ResultsAVP microinjected into the CEA in lieu of exposure to the first 2 cycles of CIE was sufficient to induce anxiety‐like behavior in these commonly used rat strains. The V1b receptor antagonist, but not an oxytocin receptor agonist, into the CEA during the first 2 withdrawal cycles suppressed anxiety. However, activation of the BLA in lieu of exposure to the first 2 cycles of CIE was insufficient to induce anxiety‐like behavior. AVP microinjection into the CEA 24 hours into withdrawal reelicited anxiety‐like behavior, and deactivation of the dm/dlPAG reduced this effect of CEA AVP.ConclusionsTaken together, this study demonstrates a role of CEA AVP and a CEA‐dm/dlPAG circuit in the development of anxiety induced by CIE. Such information is valuable for identifying novel therapeutic targets for alcohol‐ and anxiety‐associated disorders.
Epigenome‐Wide DNA Methylation Association Analysis Identified Novel Loci in Peripheral Cells for Alcohol Consumption Among European American Male Veterans
Authors: Xu Ke , Montalvo‐Ortiz Janitza L. , Zhang Xinyu , Southwick Steven M. , Krystal John H. , Pietrzak Robert H. , Gelernter Joel 
Published: August 2019

BackgroundHazardous alcohol consumption has significant adverse medical consequences. These effects may be mediated, in part, by alterations in DNA methylation. Thus, DNA methylation signatures in peripheral cells may provide biomarkers of the medical impact of alcohol use and the risk for future alcohol consumption.MethodUsing a high‐density methylation array, we characterized epigenome‐wide DNA methylation in saliva cells with respect to alcohol consumption in a large cohort of male European American veterans. In this study, DNA methylation of over 870,000 CpG DNA sites was profiled in 1,135 European American men. Alcohol consumption was assessed using the Alcohol Use Disorder Identification Test‐Consumption (AUDIT‐C). Linear regression was applied in an epigenome‐wide association study (EWAS), adjusted for confounders. Gene set enrichment analysis was performed in the KEGG database with a correction for gene length.ResultsWe found that a total of 70 CpG sites reached EWAS‐corrected significance (p < 6E‐08) with small effects on alcohol consumption for individual CpG sites, including 64 new CpG sites and 6 CpG sites that were previously reported as associated with alcohol use disorder, liver function, body mass index, and lipid metabolism. The most significant CpG site was located in SLC7A11 (t = −11.34, p = 2.66E‐28), a gene involved specifically in cysteine and glutamate transportation. The 70 significant CpG sites were located on 44 genes, including genes involved in amino acid transport and metabolism systems. We identified 68 pathways with a false discovery rate < 0.05.ConclusionsWe identified novel DNA methylation sites associated with alcohol consumption. Results may shed light on peripheral mechanisms of alcohol consumption on adverse health outcomes among heavy drinkers.
Efficacy of a Web‐Based Screening and Brief Intervention to Prevent Problematic Alcohol Use in Korea: Results of a Randomized Controlled Trial
Authors: Jo Sun‐Jin , Lee Hae Kook , Kang Kyonghwa , Joe Keun Ho , Lee Soo‐Bi 
Published: August 2019

BackgroundWeb‐based alcohol screenings and brief interventions have been shown to be effective methods for changing drinking behavior. This study evaluated the efficacy of the online‐based Brief Empowerment Program for Alcohol‐Use Monitor (on‐BEAM), a brief intervention applying personalized normative feedback (PNF) and components of motivational interviewing (MI) techniques.MethodsA community‐based, double‐blind, parallel‐group randomized controlled trial with individual randomization was conducted in Korea (registered at Clinical Research Information Service—KCT0003050). An e‐mail about participating in a survey on drinking behavior was sent to 5,684 individuals, aged 20 to 40, that were registered as part of a research panel. Male and female participants with AUDIT‐C scores of ≥4 and ≥3, respectively, were randomly assigned to either an intervention (received a drinking behavior assessment and the results with normative feedback) or control group (assessment and results without normative feedback). To evaluate the effects of the intervention with 2 sessions over the course of a month, a follow‐up assessment was performed online 4 weeks after completion of the intervention. The main outcome was the number of standard drinks consumed during the past week measured using the timeline followback method. The rate ratios (RRs) were calculated to test the effects of the intervention.ResultsIn total, 1,496 participants were randomized and 93% of them followed up. The intervention group reported consuming less alcohol during the past week (RR = 0.13; p = 0.012) than the control group. Additionally, the intervention group had fewer binge drinkers (RR = 0.69; p < 0.001) and a lower AUDIT‐C score (RR = 0.59; p = 0.009) than the control group.ConclusionsThe web‐based intervention, on‐BEAM, which applies PNF and MI components related to high‐risk drinking reduced the amount of alcohol consumption in our study population. Further research is needed to determine the duration of on‐BEAM's effects and evaluate its effectiveness in the real world.
Facilitating Screening and Brief Interventions in Primary Care: A Systematic Review and Meta‐Analysis of the AUDIT as an Indicator of Alcohol Use Disorders
Authors: Lange Shannon , Shield Kevin , Monteiro Maristela , Rehm Jürgen 
Published: August 2019

BackgroundThe Alcohol Use Disorders Identification Test (AUDIT) was developed for use in primary health care settings to identify hazardous and harmful patterns of alcohol consumption, and is often used to screen for alcohol use disorders (AUDs). This study examined the AUDIT as a screening tool for AUDs.MethodsA systematic literature search was performed of electronic bibliographic databases (CINAHL, Embase, ERIC, MEDLINE, PsycINFO, Scopus, and Web of Science) without language or geographic restrictions for original quantitative studies published before September 1, 2018, that assess the AUDIT's ability to screen for AUDs. Random‐effects meta‐regression models were constructed by sex to assess the potential determinants of the AUDIT's specificity and sensitivity. From these models and ecological data from the Global Information System on Alcohol and Health, the true‐ and false‐positive and true‐ and false‐negative proportions were determined. The number of people needed to be screened to treat 1 individual with an AUD was estimated for all countries globally where AUD data exist, using a specificity of 0.95.ResultsA total of 36 studies met inclusion criteria for the meta‐regression. The AUDIT score cut‐point was significantly associated with sensitivity and specificity. Standard drink size was found to affect the sensitivity and specificity of the AUDIT for men, but not among women. The AUDIT performs less well in identifying women compared to men, and countries with a low prevalence of AUDs have higher false‐positive rates compared to countries with a higher AUD prevalence.ConclusionsThe AUDIT does not perform well as a screening tool for identifying individuals with an AUD, especially in countries and among populations with a low AUD prevalence (e.g., among women), and thus should not be used for this purpose.
Risk of homelessness after discharge from psychiatric wards in Denmark: a nationwide register‐based cohort study
Authors: Nilsson S.F. , Laursen T.M. , Hjorthøj C. , Nordentoft M. 
Published: August 2019

ObjectiveTo examine the absolute and relative risk of homelessness following discharge from psychiatric wards in Denmark.MethodsA nationwide, register‐based, cohort study including people aged 18+ years discharged from psychiatric wards in Denmark between 1 January 2001 and 31 December 2015. We analysed associations between psychiatric diagnoses and risk of homelessness using survival analysis.ResultsA total of 126 848 psychiatric in‐patients were included accounting for 94 835 person‐years. The incidence of homelessness one year following discharge was 28.18 (95% CI 26.69−29.75) and 9.27 (95% CI 8.45−10.16) per 1000 person‐years at risk in men and women respectively. The one‐year cumulative probability of first homelessness after discharge from psychiatric wards was 1.58% (95% CI 1.48−1.68) in males and 0.55% (95% CI 0.50−0.61) in females. Substance use disorders increased the risk of homelessness after discharge with adjusted incidence rate ratios of 6.60 (95% CI 5.19−8.40) (men) and 13.06 (95% CI 9.31−18.33) (women), compared with depressive disorders. Prior history of homelessness was an important predictor for homelessness following discharge.ConclusionsThe first year following discharge from psychiatric wards is a high‐risk period of homelessness, especially when having a substance use disorder or a prior history of homeless shelter contact. Improved efforts to prevent homelessness are needed.