bluuebunny/crossref_metadata_2025 huggingface dataset:
Methotrexate
Authors: Malakouti Mona , Hoxie Dana , No Daniel J. , Jacob Sharon E.
Published: March 2018

A drug is defined as a medicine or substance that causes a physiologic effect on the body. A drug can be administered by various routes including oral, intravenous, intramuscular, topical, transdermal, or subcutaneous. The purpose of this section is to focus on common drugs used in dermatology, the drugs’ mechanisms of action, their indications and function, and adverse effects. The focus of this article is methotrexate and its usefulness in treating psoriasis as well as its adverse effects.
Risk Factors Linking Esophageal Squamous Cell Carcinoma With Head and Neck Cancer or Gastric Cancer
Authors: Onochi Kengo , Shiga Hisashi , Takahashi So , Watanabe Noboru , Fukuda Sho , Ishioka Mitsuaki , Koizumi Shigeto , Matsuhasi Tamotsu , Jin Mario , Iijima Katsunori
Published: March 2018

Goals:

To investigate retrospectively the risk factors for synchronous and metachronous cancers in the upper gastrointestinal tract in patients with superficial esophageal squamous cell carcinoma (ESCC).

Background:

In patients who have received endoscopic resection (ER) for ESCC, synchronous and metachronous cancers are frequently detected not only in the esophagus but also in the head and neck area and the stomach.

Study:

A total of 285 patients who received ER for superficial ESCC were enrolled in this analysis. These patients were periodically followed-up endoscopically. Cumulative occurrence rates of the metachronous second primary cancers were determined by Kaplan-Meier method. Risk factors for synchronous and metachronous cancers in the head and neck area and the stomach were determined by logistic regression analyses.

Results:

During a mean follow-up period of 76 months, the 5-year cumulative occurrence of metachronous esophageal, head and neck, and stomach cancer was 14.0%, 2.8%, and 4.1%, respectively. Although the presence of multiple lugol-voiding lesions in the esophagus was a significant risk factor for synchronous and metachronous head and neck cancers (odds ratio, 3.8; 95% confidence interval, 1.7-9.0), older age (>65 y) was a significant risk factor for synchronous and metachronous gastric cancer (odds ratio, 3.1; 95% confidence interval, 1.2-9.3).

Conclusions:

The risk factors for the cooccurrence of head and neck cancer and that of gastric cancer in patients with ESCC differ. This information will likely be useful for managing patients who have been treated with ER for ESCC and who possess carcinogenic potential throughout the upper gastrointestinal tract.
A Narrative Analysis of Nurses' Experiences With Meaning and Joy in Nursing Practice
Authors: Galuska Lee , Hahn Judith , Polifroni E. Carol , Crow Gregory
Published: March 2018

Health care transformation is guided by the triple aim of improving health, enhancing the patient experience, and reducing costs. Experts have recommended the addition of a fourth aim, improving the experience of providing care. They advise that achievement of the triple aim will only be possible if we create the conditions where health care workers can find meaning and joy in their work. Nurses' experiences with meaning and joy in their practice have not been well described. In an effort to fill this knowledge gap, nurses across the nation recently participated in a qualitative study to share their experiences with meaning and joy in their nursing practice. The study utilized a narrative inquiry approach with a lens of appreciation to elicit and interpret nurses' stories. The stories, recorded and archived in StoryCorps, provided rich insight into meaning and joy in nursing practice. The study captured contemporary themes that crossed practice settings and generations across the United States. Four themes emerged from the analysis, including: fulfilling purpose—“I am a nurse”; meaningful connection; impact—the wow factor; and the practice environment. The practice environment theme included 3 subthemes: teams work, leaders model the way, and opportunities to learn and grow. The themes are described and illustrated with participant quotes. The study findings build on published evidence related to meaning in nursing practice and our conceptual understanding of joy. Results align with recommendations for defining and focusing on the fourth aim: To improve the practice experiences of nurses so they can more fully contribute to achieving both the triple aim in health care and their own well-being. Specific implications for leaders and supportive practice environments are discussed.
LGBT Older Adults and Nurse Administrators
Authors: Thornton Marleen
Published: March 2018

One of the greatest health care challenges of the 21st century is the rapidly growing number of older adults in the United States. This aging population is also becoming increasingly diverse, and with this diversity comes an increased number of older adults who identify as lesbian, gay, bisexual, and transgender (LGBT). The needs and health outcomes of this specific subgroup of the older adult population cannot be extrapolated from the more general population of older adults. Nurses have the opportunity to lead health care providers in improving care for this vulnerable and sometimes invisible population. Leading this charge will require nurse executives who advocate, create care environments that are inclusive, and staff with nurses who can care for the specific needs of LGBT older adults. The purpose of this article is to raise awareness of the health needs of LGBT older adults and identify how nurse executives can advocate to improve care for this overlooked population.
Surgical Management and Evaluation of the Craniofacial Growth and Morphology in Cleidocranial Dysplasia
Authors: Greene Stephen L. , Kau Chung How , Sittitavornwong Somsak , Powell Kathlyn , Childers Noel K. , MacDougall Mary , Lamani Ejvis
Published: March 2018

Cleidocranial dysplasia (CCD, MIM 119600) is a rare autosomal dominant disorder affecting bone, cartilage, craniofacial growth, and tooth formation leading to supernumerary teeth. Few reports delineate the genotype–phenotype correlations related to the variations in craniofacial morphology and patterning of the dentition and the complexity of treating patient's malocclusion. Successful management of the craniofacial deformities in patients with CCD requires a multidisciplinary team of healthcare specialists. Approximately 70% of patients are due to point mutations in RUNX2 and <20% due to copy number variations with the remainder unidentified. There is no literature to date, describing the orthognathic management of CCD patients with deletion in one of the RUNX2 alleles. The purpose of this study was to evaluate the craniofacial morphology and dental patterning in a 14-year-old Caucasian female with CCD resulting from a novel microdeletion of RUNX2 in 1 allele. The CCD patient with RUNX2 haploinsufficiency due to microdeletion had decreased craniofacial bone and ankyloses in the permanent dentition. An altered extraction protocol of supernumerary teeth was followed in this patient. Craniofacial growth and morphologic analysis demonstrated atypical skull shape, persistent metopic suture, and decreased mandibular size.
Does Pediatric Obstructive Sleep Apnea Syndrome Cause Systemic Microvascular Dysfunction?
Authors: Koçak Hasan Emre , Acipayam Ayşe Şermin Filiz , Acipayam Harun , Erdoğan Bilgen Çakil , Elbistanli Mustafa Suphi , Kaya Kamil Hakan
Published: March 2018

The aim of this study was to evaluate whether pediatric obstructive sleep apnea syndrome (OSAS) secondary to adenoid hypertrophy causes systemic microvascular dysfunction. This is a prospective single-blinded case–control study. As the patient group, 81 patients diagnosed to have OSAS secondary to adenoid hypertrophy at our hospital between January 2016 and May 2016; as the control group, 26 healthy pediatric volunteers who presented to the hospital for health screening were included in this study. Three groups of OSAS patients were defined as mild, moderate, and severe respectively, according to the lateral nasopharynx x-ray. Patients with comorbid diseases were excluded from the study. For microvascular dysfunction, videocapillaroscopic evaluation was performed at the nailfold and capillary density (CD) and postocclusive reactive hyperemia (PORH) values were measured and statistical analysis between the groups was performed. The duration of complaints in all patients with OSAS was at least 6 months and <1 year. CD measurement in the control group and mild, moderate, and severe OSAS group was 94.1 ± 7.9, 96.9 ± 11, 94.7 ± 8.4, and 93.7 ± 9.4, respectively, with no significant difference between the groups (P > 0.05). PORH measurement in the control group and mild, moderate, and severe OSAS group was 95.6 ± 8.6, 97.9 ± 10.1, 96 ± 8.7, and 93.9 ± 9.3, respectively, with no significant difference between the groups (P > 0.05). OSAS secondary to adenoid hypertrophy in pediatric patients was demonstrated to cause no dysfunction in microvascular circulation and carried no cardiovascular risk in the early period.
Influence of Backscatter Radiation on Cranial Bone Fixation Devices
Authors: Sakamoto Yoshiaki , Koike Naoyoshi , Takei Hideyuki , Ohno Mari , Shigematsu Naoyuki , Kishi Kazuo
Published: March 2018

Postoperative radiation can cause ulcer formation, leading to the denudation of skin over alloplastic materials. The influence of backscatter radiation from fixation devices has not been investigated. The aim of this study is to evaluate backscatter dose variations for different cranial bone fixation devices in an experimental model designed to simulate postoperative radiotherapy. The authors assessed the radiation backscatter doses associated with resorbable (PLLA-PGA) and titanium plates. The samples were irradiated with 6 and 10 MV photon beams from a linear accelerator. Measurements were obtained using an ionization chamber and radiochromic films cut from the same batch. As a result, the backscatter radiation of water and PLLA-PGA proportionally decreased as the depth increased. However, the backscatter radiation of the titanium plate increased just above the plate. This depth lies in the region of the scalp. Each material showed a dose of radioactivity that was higher at 10 MV than that at 6 MV. These devices showed a significant difference, which suggested that these materials amplified the dose compared with water at 6 MV. In conclusion, it is supposed that PLLA-PGA should be used to fix the cranium to decrease the potential for radiation ulcers.
Comparing the Efficacy of Peritonsillar Injection of Tramadol With Honey in Controlling Post-Tonsillectomy Pain in Adults
Authors: Hatami Maryam , Mirjalili Mahdieh , Ayatollahi Vida , Vaziribozorg Sedighe , Zand Vahid
Published: March 2018

Introduction:

The authors investigated the effect of honey on post-tonsillectomy pain and compare its efficacy with tramadol.

Methods:

This clinical trial was performed on 60 patients with American Society of Anesthesia I and II aged between 18 and 55 years and underwent tonsillectomy. Induction of anesthesia was carried out using 2 mg/kg propofol and 0.5 atracurium following 1.5 μg/kg fentanyl administration. Group B was given tramadol at dose of 2 mg/kg and with volume of 4 mL and Group A was given normal saline with the same volume 2 mL of medications were injected using needle (25) into tonsil bed and anterior old of each tonsil by an anesthesiologist. Three minutes after injection, the surgery was performed by the same ENT residents for all patients. In the recovery room Group B received antibiotics and oral acetaminophen. Group A was given antibiotics, oral acetaminophen, and honey dissolved in 40 mL warm water every 6 hours from when the patient was fully awake. Patients in Group A were told to eat honey 3 times a day 7 days postoperatively. Pain was scored using Numeric Rating Scale at the time points of 2, 6, 12, and 24 hours as well as 3 and 7 days postoperatively. Moreover, the healing status and epithelialization degree of tonsillar bed were considered on 1 and 7 days after the surgery by ENT specialist.

Results:

The mean of pain score was significantly higher in Group A within 24 hours postoperatively as compared with Group B (P < 0.01). The mean of pain score was lower in Group B after 3 and 7 days but this difference was not statistically significant (P > 0.05). Considering restoration status and epithelialization degree of tonsillar bed on the 1st and 7th days, there was no statistically significant difference between 2 groups; however, tonsillar bed healing process was better in Group B on the 7th day.

Conclusion:

The current investigation confirmed the positive impact of tramadol on post-tonsillectomy pain relief in adults. The authors also found that honey can be used as a complementary treatment along with acetaminophen and other analgesics for reducing post-tonsillectomy pain. Considering honey impact on wound healing and its anti-inflammatory effect, it is suggested for relieving complications after surgery.
Ruptured Pseudoaneurysm of the Maxillary Artery and Its Branches Following Le Fort I Osteotomy: Evidence-Based Guidelines
Authors: Bykowski Michael R. , Hill Amber , Garland Catherine , Tobler William , Losee Joseph E. , Goldstein Jesse A.
Published: March 2018

Background:

Although rare, pseudoaneurysms (PA) can develop following Le Fort I osteotomy and lead to life-threatening hemorrhage. However, the typical presentation of a PA following a Le Fort I osteotomy is not well characterized. Evidence-based guidelines are not currently available for evaluation of PA following Le Fort I osteotomy.

Methods:

A case report is presented of a 27-year-old man who underwent Le Fort I advancement and subsequently developed a bleeding PA. A comprehensive search of journal articles was performed using the MEDLINE/PubMed database between 1964 and April 2016. Keywords and phrases used were “(osteotomy OR craniofacial OR orthognathic) AND (pseudoaneurysm OR aneurysm OR epistaxis).” Preferred Reporting Items for Systematic Reviews and Meta- Analyses (PRISMA) guidelines were followed.

Results:

The literature search yielded 13 reports of 18 patients. All 18 patients underwent Le Fort I osteotomy and subsequently developed a delayed postoperative bleeding PA. All studies were level IV or V evidence. Twenty-eight percent (N = 5) of the cases documented “excessive” intraoperative bleeding or more than 500 mL of estimated blood loss. The average time for the first bleeding episode and time until final bleed was 17.3 ± 14.3 days (range: 3–62 days) and 27.8 ± 21.2 days following surgery (range: 6–77 days), respectively. Sixty-seven percent (N = 12) had multiple episodes of bleeding. The duration between the bleeding events averaged 10.6 (± 7.9 days) with a range of 1 to 35 days. Bleeding PA's were treated with image-guided embolization (15/18 patients; 83.3%) or ligation or clamping (3/18 patients; 16.7%).

Conclusion:

In the setting of recurrent and/or delayed postoperative epistaxis following Le Fort I osteotomy, surgeons should maintain a high clinical suspicion for PA. Ruptured PA's are often preceded by multiple episodes of progressively worsening epistaxis. Based on the presented case report and pooled data from the literature, angiography is recommended to evaluate for PA in the setting of recurrent epistaxis following Le Fort I osteotomy, especially within the first 4 weeks following surgery.
Impairments in sensory-motor gating and information processing in a mouse model of Ehmt1 haploinsufficiency
Authors: Davis Brittany A. , David François , O’Regan Ciara , Adam Manal A. , Harwood Adrian J. , Crunelli Vincenzo , Isles Anthony R.
Published: March 2018

Regulators of chromatin dynamics and transcription are increasingly implicated in the aetiology of neurodevelopmental disorders (NDDs). Haploinsufficiency of EHMT1, encoding a histone methyl-transferase, is associated with several NDDs, including Kleefstra syndrome, developmental delay and autism spectrum disorder. Using a mouse model of Ehmt1 haploinsufficiency (Ehmt1D6Cre/+), we examined a number of brain and behavioural endophenotypes of relevance to NDDs. Specifically, we show that Ehmt1D6Cre/+ mice have deficits in information processing, evidenced by abnormal sensory-motor gating, a complete absence of object recognition memory and a reduced magnitude of auditory evoked potentials in both paired-pulse inhibition and mismatch negativity (MMN). The electrophysiological experiments show that differences in magnitude response to auditory stimulus were associated with marked reductions in total and evoked beta- and gamma-band oscillatory activity, as well as significant reductions in phase synchronisation. The pattern of electrophysiological deficits in Ehmt1D6Cre/+ matches those seen in control mice following administration of the selective NMDA-R antagonist, ketamine. This, coupled with reduction of Grin1 mRNA expression in Ehmt1D6Cre/+ hippocampus, suggests that Ehmt1 haploinsufficiency may lead to disruption in NMDA-R. Taken together, these data indicate that reduced Ehmt1 dosage during forebrain development leads to abnormal circuitry formation, which in turn results in profound information processing deficits. Such information processing deficits are likely paramount to our understanding of the cognitive and neurological dysfunctions shared across the NDDs associated with EHMT1 haploinsufficiency.
Crossbrowse: A versatile genome browser for visualizing comparative experimental data
Authors: Shenker Sol , Lai Eric
Published: March 2018

The recent beyond-exponential growth in diverse collections of deep sequencing datasets creates enormous opportunities for discovery, concomitant with new challenges for displaying and interpreting these data. Notably, the availability of scores of whole genome sequences in multiple species clades enables comparative studies of functional elements. However, current genome browsers do not permit effective visualization of multigenome experimental data. Here, we present CrossBrowse, a standalone desktop application for displaying and browsing cross-species genomic datasets. We utilize data standards and graphic representation of popular browsers, and incorporate an intuitive graphical visualization of genome synteny that facilitates and drives human interrogation of comparative data. Our platform permits users with minimal informatics capacity to select arbitrary sets of genomes for display, upload and configure multiple datasets, and interact with vertebrate-sized genomic datasets in real-time. We illustrate the utility of CrossBrowse with interrogation of comparative invertebrate and mammalian datasets that provide insights into diverse aspects of transcriptional and post-transcriptional regulation. Of note, we show examplars of both preservation and divergence of functional elements that cannot be inferred from sequence alignments alone. Moreover, we demonstrate how inspection of primary data using CrossBrowse exposes an artifact in a typical strategy for assigning species-specific functional elements, and drives the implementation of an improved computational strategy. We anticipate that CrossBrowse will greatly foster user-based discovery within multispecies genomic datasets, and inform their bioinformatic interpretation.
Collagen stiffness modulates MDA-MB231 cell metabolism through adhesion-mediated contractility
Authors: Mah Emma J. , McGahey Gabrielle E. , Yee Albert F. , Digman Michelle A.
Published: March 2018

Extracellular matrix (ECM) mechanical properties play a key role in cancer cell aggressiveness. Increasing substrate stiffness upregulates cancer invasion, cell contractility and focal adhesion formation. In addition to matrix properties, alteration in energy metabolism is a known characteristic of cancer cells (i.e., Warburg effect) and modulates cell invasion. However, there has been little evidence to show that substrate stiffness is able to affect cancer cell metabolism. Thus, we investigated changes in energy metabolism in response to varying collagen matrix stiffness in different cancer cells, MDA-MB231, AA375MM and U251MG and non-tumorigenic breast cell line MCF10A. Using the phasor approach to fluorescent lifetime imaging microscopy (FLIM), we measured the lifetime ratio of the free:bound state of NADH and determined if these cells altered their metabolism when plated on varying ECM density. This approach is a powerful tool that allows us to map the metabolic trajectory of each living cell within its cellular compartments. In our studies, we found that MDA-MB231 cells had an increase in bound NADH, indicating oxidative phosphorylation (OXPHOS), as collagen substrate density decreased. When inhibiting myosin-II contractility with Y-27632 or blebbistatin, the MDA-MB231 cells on glass shifted from glycolysis (GLY) to OXPHOS, confirming the intricate relationship between mechanosensing and metabolism in these highly invasive tumor cells. The human glioblastoma cell line, U251MG, showed an opposite trend compared to the invasive MDA-MB231 cells. However, the human melanoma cell line, A375MM did not show any significant changes in metabolic indices when they were grown on surfaces with varying collagen density but changed when grown on glass surfaces. MCF10A cells showed no changes in metabolism across all surfaces. In addition, OXPHOS or GLY inhibitors to MDA-MB231 cells showed dramatic shifts from OXPHOS to GLY or vice versa. There were slight changes detected in MCF10A cells. These results provide an important link between cellular metabolism, contractility and ECM stiffness in human breast cancer.
High Numerical Aperture Epi-illumination Selective Plane Illumination Microscopy
Authors: Yang Bin , Wang Yina , Feng Siyu , Pessino Veronica , Stuurman Nico , Huang Bo
Published: March 2018

Selective-plane illumination microscopy (SPIM) provides unparalleled advantages for long-term volumetric imaging of living organisms. In order to achieve high-resolution imaging in common biological sample holders, we designed a high numerical aperture (NA) epi-illumination SPIM (eSPIM) system, which utilizes a single objective and has an identical sample interface as an inverted fluorescence microscope with no additional reflection elements. This system has an effective detection NA of > 1.06. We demonstrated multicolor and fast volumetric imaging of live cells and single-molecule super-resolution microscopy using our system.
Sexual selection and inbreeding: two efficient ways to limit the accumulation of deleterious mutations
Authors: Noël E. , Fruitet E. , Lelaurin D. , Bonel N. , Ségard A. , Sarda V. , Jarne P. , David P.
Published: March 2018

Theory and empirical data showed that two processes can boost selection against deleterious mutations, thus facilitating the purging of the mutation load: inbreeding, by exposing recessive deleterious alleles to selection in homozygous form, and sexual selection, by enhancing the relative reproductive success of males with small mutation loads. These processes tend to be mutually exclusive because sexual selection is reduced under mating systems that promote inbreeding, such as self-fertilization in hermaphrodites. We estimated the relative efficiency of inbreeding and sexual selection at purging the genetic load, using 50 generations of experimental evolution, in a hermaphroditic snail (Physa acuta). To this end, we generated lines that were exposed to various intensities of inbreeding, sexual selection (on the male function) and nonsexual selection (on the female function). We measured how these regimes affected the mutation load, quantified through the survival of outcrossed and selfed juveniles. We found that juvenile survival strongly decreased in outbred lines with reduced male selection, but not when female selection was relaxed, showing that male-specific sexual selection does purge deleterious mutations. However, in lines exposed to inbreeding, where sexual selection was also relaxed, survival did not decrease, and even increased for self-fertilized juveniles, showing that purging through inbreeding can compensate for the absence of sexual selection. Our results point to the further question of whether a mixed strategy combining the advantages of both mechanisms of genetic purging could be evolutionary stable.
Compartmentalized RNA catalysis in membrane - free coacervate protocells
Authors: Drobot Björn , Iglesias-Artola Juan M. , Vay Kris Le , Mayr Viktoria , Kar Mrityunjoy , Kreysing Moritz , Mutschler Hannes , Tang T-Y. Dora
Published: March 2018

Phase separation of mixtures of oppositely charged polymers provides a simple and direct route to compartmentalization via coacervation, which may have been important for driving primitive reactions as part of the RNA world hypothesis. However, to date, RNA catalysis has not been reconciled with coacervation. Here we demonstrate that RNA catalysis is viable within coacervate microdroplets and further show that these membrane-free droplets can selectively retain longer length RNAs while permitting transfer of lower molecular weight oligonucleotides.
Testing competing models of dorsal anterior cingulate
Authors: Vassena Eliana , Deraeve James , Alexander William H.
Published: March 2018

Recent theories have attempted to provide unifying accounts of dorsal anterior cingulate cortex (dACC), a region routinely observed in studies of cognitive control and decision-making. Despite the proliferation of frameworks, rigorous empirical testing has lagged behind theory. Here we test competing predictions of three accounts of dACC using a simple value-based decision-making task. We find that the Predicted Response-Outcome model provides an integrative and parsimonious account of our results. Our results highlight the need for increased emphasis on empirical tests of theoretical frameworks.
Intellectual Synthesis in Mentorship Determines Success in Academic Careers
Authors: Liénard Jean F. , Achakulvisut Titipat , Acuna Daniel E. , David Stephen V.
Published: March 2018

As academic careers become more competitive, junior scientists need to understand the value that mentorship brings to their success in academia. Previous research has found that, unsurprisingly, successful mentors tend to train successful students. But what characteristics of this relationship predict success, and how? We analyzed an open-access database of about 20,000 researchers who have undergone both graduate and postdoctoral training, compiled across several fields of biomedical science. Our results show that postdoctoral mentors were more instrumental to trainees’ success compared to graduate mentors. A trainee’s success in academia was predicted by the degree of intellectual synthesis with their mentors, resulting from fusing the influence of disparate advisors. This suggests that junior scientists should have increased chances of success by training with and linking the ideas of mentors from different fields. We discuss the implications of these results for choosing mentors and determining the duration of postdoctoral training.
RNA-directed activation of cytoplasmic dynein-1 in reconstituted transport RNPs
Authors: McClintock Mark A. , Dix Carly I. , Johnson Christopher M. , McLaughlin Stephen H. , Maizels Rory J. , Hoang Ha Thi , Bullock Simon L.
Published: March 2018

Polarised mRNA transport is a prevalent mechanism for spatial control of protein synthesis. However, the composition of transported ribonucleoprotein particles (RNPs) and the regulation of their movement are poorly understood. We have reconstituted microtubule minus end-directed transport of mRNAs using purified components. A Bicaudal-D (BicD) adaptor protein and the RNA-binding protein Egalitarian (Egl) are sufficient for long-distance mRNA transport by the dynein motor and its accessory complex dynactin, thus defining a minimal transport-competent RNP. Unexpectedly, the RNA is required for robust activation of dynein motility. We show that a cis-acting RNA localisation signal stabilises the interaction of Egl with BicD, which licenses the latter protein to recruit dynein and dynactin. Our data support a model for BicD activation based on RNA-induced occupancy of two Egl-binding sites on the BicD dimer. Scaffolding of adaptor protein assemblies by cargoes is an attractive mechanism for regulating intracellular transport.
Lattice tilt and strain mapped by X-ray scanning nanodiffraction in compositionally graded SiGe/Si microcrystals
Authors: Meduňa Mojmír , Isa Fabio , Jung Arik , Marzegalli Anna , Albani Marco , Isella Giovanni , Zweiacker Kai , Miglio Leo , von Känel Hans
Published: March 2018

The scanning X-ray nanodiffraction technique is used to reconstruct the three-dimensional distribution of lattice strain and Ge concentration in compositionally graded Si1−x
Ge
x
microcrystals grown epitaxially on Si pillars. The reconstructed crystal shape qualitatively agrees with scanning electron micrographs and the calculated three-dimensional distribution of lattice tilt quantitatively matches finite-element method simulations. The grading of the Ge content obtained from reciprocal-space maps corresponds to the nominal grading of the epitaxial growth recipe. The X-ray measurements confirm strain calculations, according to which the lattice curvature of the microcrystals is dominated by the misfit strain, while the thermal strain contributes negligibly. The nanodiffraction experiments also indicate that the strain in narrow microcrystals on 2 × 2 µm Si pillars is relaxed purely elastically, while in wider microcrystals on 5 × 5 µm Si pillars, plastic relaxation by means of dislocations sets in. This confirms previous work on these structures using transmission electron microscopy and defect etching.
In situ study of the kinetics of growth of Pb nanoparticles embedded in a PbO–B2O3 glass
Authors: Gorgeski Andreia , Craievich Aldo Felix , Corrêa Leonardo Marcon , Montoro Luciano Andrei , Kellermann Guinther
Published: March 2018

The process of growth of liquid Pb nanoparticles embedded in a lead borate glass was investigated by transmission electron microscopy (TEM) and by in situ small-angle X-ray scattering (SAXS) during isothermal annealing at different temperatures within the 649–679 K range. A TEM study at room temperature of the glass–Pb nanoparticle composite, previously subjected to isothermal annealing, showed the presence of a number of nearly spherical Pb nanocrystals with some size dispersion. The analysis of several series of experimental SAXS curves recorded in situ, for increasing periods of time of isothermal annealing at different temperatures, allowed the authors to determine time and temperature dependences of the radius distribution functions of the growing spherical Pb nanoparticles. Since all selected annealing temperatures were higher than the melting temperature of bulk Pb, the Pb nanoparticles were in all cases in the liquid state during the whole growth process. A fast increase in the total volume of Pb droplets was observed during the initial stages of annealing, which indicated that the Pb droplets grow because of the incorporation of Pb atoms dispersed in the glass matrix. For more advanced stages of droplet growth, when the concentration of Pb atoms becomes close to its equilibrium concentration, the time dependences of the average radius, number density and total volume of Pb droplets are those predicted by the classical theory of coarsening proposed by Lifshitz–Slyosov–Wagner. Furthermore, it has been established that the Pb nanodroplets preserve their spherical shape and their relative dispersion in size through the whole coarsening process and that the activation energy for diffusion of Pb atoms and growth of Pb droplets embedded in the studied glass is E
a = 2.65 ± 0.09 eV per atom.
Development of a joint refinement model for the spin-resolved one-electron reduced density matrix using different data sets
Authors: Gueddida Saber , Yan Zeyin , Gillet Jean-Michel
Published: March 2018

The paper describes a joint refinement model of the spin-resolved one-electron reduced density matrix using simultaneously magnetic structure factors and magnetic directional Compton profiles. The model is guided by two strategies: (i) variation of basis functions and (ii) variation of the spin population matrix. The implementation for a finite system is based on an expansion of the natural orbitals on basis sets. To show the potential benefits brought by the joint refinement model, the paper also presents the refinement results using magnetic structure factors only. The joint refinement model provides very satisfactory results reproducing the pseudo-data. In particular, magnetic Compton profiles have a strong effect not only on the off-diagonal elements of the spin-resolved one-electron reduced density matrix but also on its diagonal elements.
Construction of poly-ellipsoidal grain shapes from SMT imaging on sand, and the development of a new DEM contact detection algorithm
Authors: Zhang Boning , Regueiro Richard , Druckrey Andrew , Alshibli Khalid
Published: March 2018

Purpose

This paper aims to construct smooth poly-ellipsoid shapes from synchrotron microcomputed tomography (SMT) images on sand and to develop a new discrete element method (DEM) contact detection algorithm.

Design/methodology/approach

Voxelated images generated by SMT on Colorado Mason sand are processed to construct smooth poly-ellipsoidal particle approximations. For DEM contact detection, cuboidal shape approximations to the poly-ellipsoids are used to speed up contact detection.

Findings

The poly-ellipsoid particle shape approximation to Colorado Mason sand grains is better than a simpler ellipsoidal approximation. The new DEM contact algorithm leads to significant speedup and accuracy is maintained.

Research limitations/implications

The paper limits particle shape approximation to smooth poly-ellipsoids.

Practical implications

Poly-ellipsoids provide asymmetry of particle shapes as compared to ellipsoids, thus allowing closer representation of real sand grain shapes that may be angular and unsymmetric. When incorporated in a DEM for computation, the poly-ellipsoids allow better representation of particle rolling, sliding and interlocking phenomena.

Originality/value

Method to construct poly-ellipsoid particle shapes from SMT data on real sands and computationally efficient DEM contact detection algorithm for poly-ellipsoids.
Uncertain dynamic responses of imprecisely defined arbitrary order fractionally damped beam subject to various loads
Authors: Behera Diptiranjan , Huang Hong-Zhong , Tapaswini Smita
Published: March 2018

Purpose

Recently, fractional differential equations have been used to model various physical and engineering problems. One may need a reliable and efficient numerical technique for the solution of these types of differential equations, as sometimes it is not easy to get the analytical solution. However, in general, in the existing investigations, involved parameters and variables are defined exactly, whereas in actual practice it may contain uncertainty because of error in observations, maintenance induced error, etc. Therefore, the purpose of this paper is to find the dynamic response of fractionally damped beam approximately under fuzzy and interval uncertainty.

Design/methodology/approach

Here, a semi analytical approach, variational iteration method (VIM), has been considered for the solution. A newly developed form of fuzzy numbers known as double parametric form has been applied to model the uncertainty involved in the system parameters and variables.

Findings

VIM has been successfully implemented along with double parametric form of fuzzy number to find the uncertain dynamic responses of the fractionally damped beam. The advantage of this approach is that the solution can be written in power series or compact form. Also, this method converges rapidly to have the accurate solution. The uncertain responses subject to impulse and step loads have also been computed and the behaviours of the responses are analysed. Applying the double parametric form, it reduces the computational cost without separating the fuzzy equation into coupled differential equations as done in traditional approaches.

Originality/value

Uncertain dynamic responses of fuzzy fractionally damped beam using the newly developed double parametric form of fuzzy numbers subject to unit step and impulse loads have been obtained. Gaussian fuzzy numbers are used to model the uncertainties. In the methodology using the alpha cut form, corresponding beam equation is first converted to an interval-based fuzzy equation. Next, it has been transformed to crisp form by applying double parametric form of fuzzy numbers. Finally, VIM has been applied to solve the same for the general fuzzy responses. Various numerical examples have been taken in to consideration.
A new sequential sampling method for constructing the high-order polynomial surrogate models
Authors: Wu Jinglai , Luo Zhen , Zhang Nong , Gao Wei
Published: March 2018

Purpose

This paper aims to study the sampling methods (or design of experiments) which have a large influence on the performance of the surrogate model. To improve the adaptability of modelling, a new sequential sampling method termed as sequential Chebyshev sampling method (SCSM) is proposed in this study.

Design/methodology/approach

The high-order polynomials are used to construct the global surrogated model, which retains the advantages of the traditional low-order polynomial models while overcoming their disadvantage in accuracy. First, the zeros of Chebyshev polynomials with the highest allowable order will be used as sampling candidates to improve the stability and accuracy of the high-order polynomial model. In the second step, some initial sampling points will be selected from the candidates by using a coordinate alternation algorithm, which keeps the initial sampling set uniformly distributed. Third, a fast sequential sampling scheme based on the space-filling principle is developed to collect more samples from the candidates, and the order of polynomial model is also updated in this procedure. The final surrogate model will be determined as the polynomial that has the largest adjusted R-square after the sequential sampling is terminated.

Findings

The SCSM has better performance in efficiency, accuracy and stability compared with several popular sequential sampling methods, e.g. LOLA-Voronoi algorithm and global Monte Carlo method from the SED toolbox, and the Halton sequence.

Originality/value

The SCSM has good performance in building the high-order surrogate model, including the high stability and accuracy, which may save a large amount of cost in solving complicated engineering design or optimisation problems.
Robust topology optimization for continuum structures with random loads
Authors: Liu Jie , Wen Guilin , Qing Qixiang , Li Fangyi , Xie Yi Min
Published: March 2018

Purpose

This paper aims to tackle the challenge topic of continuum structural layout in the presence of random loads and to develop an efficient robust method.

Design/methodology/approach

An innovative robust topology optimization approach for continuum structures with random applied loads is reported. Simultaneous minimization of the expectation and the variance of the structural compliance is performed. Uncertain load vectors are dealt with by using additional uncertain pseudo random load vectors. The sensitivity information of the robust objective function is obtained approximately by using the Taylor expansion technique. The design problem is solved using bi-directional evolutionary structural optimization method with the derived sensitivity numbers.

Findings

The numerical examples show the significant topological changes of the robust solutions compared with the equivalent deterministic solutions.

Originality/value

A simple yet efficient robust topology optimization approach for continuum structures with random applied loads is developed. The computational time scales linearly with the number of applied loads with uncertainty, which is very efficient when compared with Monte Carlo-based optimization method.
Older and Wiser: How CEOs’ Time Perspective Influences Long‐Term Investments in Environmentally Responsible Technologies
Authors: Ortiz‐de‐Mandojana Natalia , Bansal Pratima , Aragón‐Correa J. Alberto
Published: March 2018

Most theories of corporate governance argue that chief executive officers (CEOs) take less risk as they near the end of their career, and therefore are less likely to make major investments. This prediction is based on decisions related to firm‐specific benefits; however, it may not be generalizable to decisions that involve broad societal goals. In terms of societal investments, CEOs with a longer time perspective may be more likely, rather than less likely, to invest. In this paper, we argue that a CEO's future time perspective is fostered by shorter career horizons, longer tenures, higher organizational ownership and less short‐term compensation. We test these hypotheses on 150 observations from the US investor‐owned electric power generation sector over a three‐year unbalanced sample (64.3% of the population). We applied random‐effects generalized least squares (GLS) estimations to test our hypotheses, and found support for three out of four hypothesized relationships.
International Evidence on the Determinants of Organizational Ethical Vulnerability
Authors: Ullah Subhan , Ahmad Sardar , Akbar Saeed , Kodwani Devendra
Published: March 2018

This paper proposes a model to explain what makes organizations ethically vulnerable. Drawing upon legitimacy, institutional, agency and individual moral reasoning theories we consider three sets of explanatory factors and examine their association with organizational ethical vulnerability. The three sets comprise external institutional context, internal corporate governance mechanisms and organizational ethical infrastructure. We combine these three sets of factors and develop an analytical framework for classifying ethical issues and propose a new model of organizational ethical vulnerability. We test our model on a sample of 253 firms that were involved in ethical misconduct and compare them with a matched sample of the same number of firms from 28 different countries. The results suggest that weak regulatory environment and internal corporate governance, combined with profitability warnings or losses in the preceding year, increase organizational ethical vulnerability. We find counterintuitive evidence suggesting that firms’ involvement in bribery and corruption prevention training programmes is positively associated with the likelihood of ethical vulnerability. By synthesizing insights about individual and corporate behaviour from multiple theories, this study extends existing analytical literature on business ethics. Our findings have implications for firms’ external regulatory settings, corporate governance mechanisms and organizational ethical infrastructure.
From waste product to blood, brains and narratives: developing a pluralist sociology of contributions to health research
Authors: Boylan Anne‐Marie R. , Locock Louise , Machin Laura
Published: March 2018

The aim of this paper is to examine the meaning of the concept of donation in health research. Drawing on a set of narrative interviews with people invited to donate biosamples for research and a range of other studies, we identify several conceptual themes that speak to the complexity of the current landscape of critical thinking about donation. These conceptual themes are: the language of ‘donation’; a hierarchy of biosamples; alternative informational value; narratives as donation; coincidental donation, convenience and degree of invasiveness; and rights, consent and benefits of research participation. We call for a reconceptualisation of research donation to encompass not only the numerous types of sample readily classed as donations, but also other types of data and contributions, including narrative interviews, psychometric data, patient‐reported outcome measures, record‐linkage, and time and effort. We argue for the development of a pluralist sociology of research donations, and suggest that a ‘sociology of research contributions’ might better capture this complexity.
Sex Work, Sensory Urbanism and Visual Criminology: Exploring the Role of the Senses in Shaping Residential Perceptions of Brothels in Blackpool
Authors: Cooper Emily , Cook Ian R. , Bilby Charlotte
Published: March 2018

Urban studies and criminology have much to offer each other, but the links between the two have so far been underexplored. This article is an illustration of how aspects of both can, and should, be brought into conversation: namely the literatures on sensory urbanism (in urban studies) and visual criminology. The benefits of doing so are evidenced by a case study exploring the ways in which the senses shape residents’ perceptions of brothels in Blackpool. Three key findings emerge from the case study. First, the residents interviewed tended to focus on the visual aspects of brothels rather than other sensory aspects. Nevertheless, touch and smell (and their interaction with the visual) also played small but important roles in shaping residential perceptions. Second, residential perceptions of sex work and brothels are linked to, and encompass, a plurality of emotional responses. Third, while the residents could see or hear little of what was happening inside the brothels, they often sought out sensory clues from outside, typically drawn from the architectural features of the brothels. Such insights, we argue, are made possible by, and highlight the possibilities of, the bringing together of urban studies and criminology.
Drug Contamination of U.S. Paper Currency and Forensic Relevance of Canine Alert to Paper Currency: A Critical Review of the Scientific Literature
Authors: Poupko Jay M. , Hearn William Lee , Rossano Federico
Published: March 2018

Several studies have reported on wide‐spread contamination of U.S. paper currency with cocaine and to a lesser extent other illicit drugs. Canines are trained and employed to search for and alert to drugs. Canine alert to currency has been used as evidence that currency has been directly involved in illicit drug trafficking to justify currency seizure and forfeiture. This assertion, particularly when the only evidence is based upon canine alert, has been challenged in the courts considering that most currency in circulation is contaminated with cocaine. Comprehensive review of the scientific literature establishes that (i) 67–100% of circulated U.S. currency is contaminated with cocaine ranging from a few nanograms to over one milligram/bill (ii) various biological and environmental parameters impact canine alert to drugs. It is concluded that canine alert to U.S. currency is not sufficiently reliable to determine that currency was directly used in an illicit drug transaction.
Massively Parallel Sequencing of Forensic STRs Using the Ion Chef™ and the Ion S5™ XL Systems,
Authors: Wang Le , Chen Man , Wu Bo , Liu Yi‐Cheng , Zhang Guang‐Feng , Jiang Li , Xu Xiu‐Lan , Zhao Xing‐Chun , Ji An‐Quan , Ye Jian
Published: March 2018

Next‐generation sequencing (NGS) has been used to genotype forensic short tandem repeat (STR) markers for individual identification and kinship analysis. STR data from several NGS platforms have been published, but forensic application trials using the Ion S5™ XL system have not been reported. In this work, we report sensitivity, reproducibility, mixture, simulated degradation, and casework sample data on the Ion Chef™ and S5™ XL systems using an early access 25‐plex panel. Sensitivity experiments showed that over 97% of the alleles were detectable with down to 62 pg input of genomic DNA. In mixture studies, alleles from minor contributors were correctly assigned at 1:9 and 9:1 ratios. NGS successfully gave 12 full genotype results from 13 challenging casework samples, compared with five full results using the CE platform. In conclusion, the Ion Chef™ and the Ion S5™ XL systems provided an alternative and promising approach for forensic STR genotyping.