bluuebunny/crossref_metadata_2025 huggingface dataset:
Childhood Trauma, Perceived Stress, and Hair Cortisol in Adults With and Without Cardiovascular Disease
Authors: Bossé Stéphanie , Stalder Tobias , D'Antono Bianca
Published: March 2018

Objective

Childhood trauma has been associated with greater psychological and physical morbidity, including a greater risk of developing cardiovascular disease (CVD). This may partially reflect trauma-induced disturbances in how stress is later perceived and regulated. This study evaluated the associations of childhood trauma with perceived stress and hair cortisol concentrations (HCC) in a large sample of adults with coronary artery disease (CAD) and in non-CVD patients experiencing other nonfatal illnesses. Whether sex, age, or CVD status influenced these associations was also examined.

Methods

A total of 1124 men and women (aged 65.2 [6.9] years) recruited from a hospital cohort completed the Childhood Trauma and Perceived Stress Questionnaires, whereas hair samples were obtained from 598 participants. Health status was confirmed via medical records.

Results

Moderate to severe childhood trauma was experienced by 359 participants. Childhood trauma was associated with greater perceived stress levels for the past 2 years (r= .308,p= .01; β = 0.263,p< .001), but not 3-month cortisol secretion in hair. Perceived stress correlated negatively with age (r= −.241,p< .001). In secondary analyses, age moderated the relation between sexual abuse and perceived stress (β = −0.067,p= .016). Although sexual abuse was associated with greater levels of perceived stress among all participants, this relation was strongest in younger individuals.

Conclusions

Participants who experienced trauma in their youth reported greater levels of perceived stress, but not HCC, in late adulthood. Whether this suggests intact hypothalamic-pituitary-adrenal regulation in those exposed to childhood trauma or whether this reflects the characteristics of our sample requires further investigation.
Residual Symptoms After Treatment for Depression in Patients With Coronary Heart Disease
Authors: Carney Robert M. , Freedland Kenneth E. , Steinmeyer Brian C. , Rubin Eugene H. , Rich Michael W.
Published: March 2018

Objective

Depression is associated with an increased risk of mortality in patients with coronary heart disease (CHD). The risk may be reduced in patients who remit with adequate treatment, but few patients achieve complete remission. The purpose of this study was to identify the symptoms that persist despite aggressive treatment for depression in patients with CHD.

Methods

One hundred twenty-five patients with stable CHD who met the DSM-IV criteria for a moderate-to-severe major depressive episode completed treatment with cognitive behavior therapy, either alone or combined with an antidepressant, for up to 16 weeks. Depression symptoms were assessed at baseline and after 16 weeks of treatment.

Results

The M (SD) Beck Depression Inventory scores were 30.0 (8.6) at baseline and 8.3 (7.5) at 16 weeks. Seventy seven (61%) of the participants who completed treatment met remission criteria (Hamilton Rating Scale for Depression ≤7) at 16 weeks. Loss of energy and fatigue were the most common posttreatment symptoms both in remitters (n = 44, 57%; n = 34, 44.2%) and nonremitters (n = 42, 87.5%; n = 35, 72.9%). These symptoms were not predicted by baseline depression severity, anxiety, demographic, or medical variables including inflammatory markers or cardiac functioning or by medical events during depression treatment.

Conclusions

Fatigue and loss of energy often persist in patients with CHD even after otherwise successful treatment for major depression. These residual symptoms may increase the risks of relapse and mortality. Development of effective interventions for these persistent symptoms is a priority for future research.
Catatonic Stupor in Schizophrenic Disorders and Subsequent Medical Complications and Mortality
Authors: Funayama Michitaka , Takata Taketo , Koreki Akihiro , Ogino Satoyuki , Mimura Masaru
Published: March 2018

Objective

Although catatonia can occur secondary to a general medical condition, catatonia itself has been known to lead to various medical compolications. Although case reports on the association of catatonia with subsequent medical complications have been documented, no comprehensive large-scale study has been performed. To investigate specific medical complications after catatonia, we conducted a retrospective cohort study of specific medical complications of schizophrenia patients with catatonia.

Methods

The 1719 schizophrenia inpatients in our study were categorized into two groups: the catatonia group, i.e., those who exhibited catatonic stupor while they were hospitalized, and the noncatatonia group, i.e., those who never exhibited catatonic stupor. Differences between the two groups in the occurrence of subsequent medical complications were examined using linear and logistic regression analyses, and models were adjusted for potentially confounding factors.

Results

The catatonia group had an increased risk for mortality (odds ratio = 4.8, 95% confidence interval = 2.0–10.6, p < .01) and certain specific medical complications, i.e., pneumonia, urinary tract infection, sepsis, disseminated intravascular coagulation, rhabdomyolysis, dehydration, deep venous thrombosis, pulmonary embolism, urinary retention, decubitus, arrhythmia, renal failure, neuroleptic malignant syndrome, hypernatremia, and liver dysfunction (all p values < .01, except for deep venous thrombosis, p = .04 in the multiple linear regression analysis).

Conclusions

Catatonic stupor in schizophrenia substantially raises the risk for specific medical complications and mortality. Hyperactivity of the sympathetic nervous system, dehydration, and immobility, which are frequently involved in catatonia, might contribute to these specific medical complications. In catatonia, meticulous care for both mental and medical conditions should be taken to reduce the risk of adverse medical consequences.
Incidence and Causes of Adverse Events in Diagnostic Radiological Studies Requiring Anesthesia in the Wake-Up Safe Registry
Authors: Khawaja Asad A. , Tumin Dmitry , Beltran Ralph J. , Tobias Joseph D. , Uffman Joshua C.
Published: March 2018

Objectives

General anesthesia or sedation can facilitate the completion of diagnostic radiological studies in children. We evaluated the incidence, predictors, and causes of adverse events (AEs) when general anesthesia is provided for diagnostic radiological imaging.

Methods

Deidentified data from 24 pediatric tertiary care hospitals participating in the Wake-Up Safe registry during 2010–2015 were obtained for analysis. Children 18 years or younger receiving general anesthesia for radiological procedures were identified using Current Procedural Terminology codes, and reported AEs were analyzed if they were associated with anesthetic care at magnetic resonance imaging or computed tomography locations. Logistic regression was used to determine predictors of AE occurrence in cases with complete covariate data.

Results

We identified 175,486 anesthetics for diagnostic radiological exams, compared with 83 AEs in magnetic resonance imaging or computed tomography locations (AE incidence of 0.05%). In multivariable analysis, AEs were more likely among patients with American Society of Anesthesiologists physical status IV compared with American Society of Anesthesiologists physical status I patients (adjusted odds ratio, 8.9; 95% confidence interval, 2.8–28.0; P < 0.001). Twenty-three AEs resulted in harm to the patient, whereas 32 AEs required unplanned hospital or intensive care unit admission. Anesthetic complications or issues were the most common cause of AEs (n = 52).

Conclusions

Anesthesia provided for pediatric radiological studies is very safe and with an overall low AE incidence. The contribution of anesthetic complications to reported AEs suggests opportunities for further process improvement in this setting.
Trophic factors in the treatment and prevention of alimentary tract mucositis
Authors: Rathe Mathias , Shen Rene L. , Sangild Per T.
Published: March 2018

Purpose of review

Mucositis is a common adverse effect of cytotoxic anticancer treatment with serious implications for the quality of life, morbidity and mortality of cancers patients. Although, evidence supporting the use of certain treatments exists there is no gold standard for preventing or treating mucositis. Current management strategies are scarce with recommendations referring primarily to specific cytotoxic treatment regimens in certain clinical scenarios.

Recent findings

Trophic factors may contribute to preserve epithelial integrity, function, and accelerate regeneration after chemotherapeutic treatment. Accordingly, various growth factors have been evaluated in the prevention or treatment of alimentary tract mucositis. However, in spite of often showing promising results in preclinical testing currently perlifermin is the only trophic factor recommended for the prevention of mucositis.

More knowledge from representative preclinical models, and testing growth factor interventions across different models, may be the key to advance the field from basic science to clinical application of new growth factors. For promising new therapies, subsequent establishment of adequately powered clinical trials and uniform reporting of mucositis, are important elements to help establish new standard interventions that can be included into the continuously updated clinical recommendations for treatment of mucositis.
Factors Associated With Healthcare-Acquired Catheter-Associated Urinary Tract Infections
Authors: Park Jung In , Bliss Donna Z. , Chi Chih-Lin , Delaney Connie W. , Westra Bonnie L.
Published: March 2018

PURPOSE:

The purpose of this study was to identify factors associated with healthcare-acquired catheter-associated urinary tract infections (HA-CAUTIs) using multiple data sources and data mining techniques.

SUBJECTS AND SETTING:

Three data sets were integrated for analysis: electronic health record data from a university hospital in the Midwestern United States was combined with staffing and environmental data from the hospital's National Database of Nursing Quality Indicators and a list of patients with HA-CAUTIs.

METHODS:

Three data mining techniques were used for identification of factors associated with HA-CAUTI: decision trees, logistic regression, and support vector machines.

RESULTS:

Fewer total nursing hours per patient-day, lower percentage of direct care RNs with specialty nursing certification, higher percentage of direct care RNs with associate's degree in nursing, and higher percentage of direct care RNs with BSN, MSN, or doctoral degree are associated with HA-CAUTI occurrence. The results also support the association of the following factors with HA-CAUTI identified by previous studies: female gender; older age (>50 years); longer length of stay; severe underlying disease; glucose lab results (>200 mg/dL); longer use of the catheter; and RN staffing.

CONCLUSIONS:

Additional findings from this study demonstrated that the presence of more nurses with specialty nursing certifications can reduce HA-CAUTI occurrence. While there may be valid reasons for leaving in a urinary catheter, findings show that having a catheter in for more than 48 hours contributes to HA-CAUTI occurrence. Finally, the findings suggest that more nursing hours per patient-day are related to better patient outcomes.
Decreasing Incidence of Medical Device–Related Pressure Injuries in a Small Community Hospital
Authors: Monarca Melissa C. , Marteka Patty , Breda Karen
Published: March 2018

One-third of hospital-acquired pressure injuries are related to medical devices. The purpose of this quality improvement project was to create an evidence-based guideline in one acute care hospital setting for the prevention of medical device–related pressure injuries (MDRPIs) and to implement the hospital-wide use of a new nasogastric tube securement device to offload pressure to the nares. The first phase of this project comprised development of a guideline along with multiple education opportunities. The second phase of this project consisted of evaluation and subsequent conversion to a new nasogastric tube securement device. This project led to reduced MDRPI incidence rates over the past 12 months.
Ostomy Creation for Palliative Care of Patients With Nonresectable Colorectal Cancer and Bowel Obstruction
Authors: Pickard Colette , Thomas Rachel , Robertson Isabell , Macdonald Angus
Published: March 2018

PURPOSE:

The purpose of this study was to review our experience with palliative ostomy surgery in patients with bowel obstruction and advanced stage colorectal cancer.

DESIGN:

A descriptive, retrospective review of data from a prospectively collected clinical database.

SUBJECTS AND SETTING:

The sample comprised 86 patients (55 male) who underwent palliative surgery between October 1998 and January 2009.

METHODS:

All patients undergoing palliative stoma formation without resection for colorectal carcinoma were identified from a prospectively compiled colorectal cancer database. Patients having colorectal stent placement and bypass surgery were excluded from analysis.

RESULTS:

The median age at surgery was 71 years (interquartile range, 65-79 years). The median survival following ostomy creation was 103 days (interquartile range, 19-263 days). Sixty-nine percent of participants (n = 59) survived 30 days and 18% (n=16) survived 12 months.

CONCLUSIONS:

Our results confirm that patients undergoing palliative stoma formation have limited life expectancy. Nevertheless, these findings are encouraging when compared to the anticipated outcomes of untreated bowel obstruction.
Fish polyomaviruses belong to two distinct evolutionary lineages
Authors: Van Doorslaer Koenraad , Kraberger Simona , Austin Charlotte , Farkas Kata , Bergeman Melissa , Paunil Emma , Davison William , Varsani Arvind
Published: March 2018

The Polyomaviridae is a diverse family of circular double-stranded DNA viruses. Polyomaviruses have been isolated from a wide array of animal hosts. An understanding of the evolutionary and ecological dynamics of these viruses is essential to understanding the pathogenicity of polyomaviruses. Using a high throughput sequencing approach, we identified a novel polyomavirus in an emerald notothen (Trematomus bernacchii) sampled in the Ross sea (Antarctica), expanding the known number of fish-associated polyomaviruses. Our analysis suggests that polyomaviruses belong to three main evolutionary clades; the first clade is made up of all recognized terrestrial polyomaviruses. The fish-associated polyomaviruses are not monophyletic, and belong to two divergent evolutionary lineages. The fish viruses provide evidence that the evolution of the key viral large T protein involves gain and loss of distinct domains.
Genetic basis of thermal plasticity variation inDrosophila melanogasterbody size
Authors: Lafuente E , Duneau D , Beldade P
Published: March 2018

Body size is a quantitative trait that is closely associated to fitness and under the control of both genetic and environmental factors. While developmental plasticity for this and other traits is heritable and under selection, little is known about the genetic basis for variation in plasticity that can provide the raw material for its evolution. We quantified genetic variation for body size plasticity inDrosophila melanogasterby measuring thorax and abdomen length of females reared at two temperatures from a panel representing naturally segregating alleles, the Drosophila Genetic Reference Panel (DGRP). We found variation between genotypes for the levels and direction of thermal plasticity in size of both body parts. We then used a Genome-Wide Association Study (GWAS) approach to unravel the genetic basis of inter-genotype variation in body size plasticity, and used different approaches to validate selected QTLs and to explore potential pleiotropic effects. We found mostly “private QTLs”, with little overlap between the candidate loci underlying variation in plasticity for thorax versus abdomen size, for different properties of the plastic response, and for size versus size plasticity. We also found that the putative functions of plasticity QTLs were diverse and that alleles for higher plasticity were found at lower frequencies in the target population. Importantly, a number of our plasticity QTLs have been targets of selection in other populations. Our data sheds light onto the genetic basis of inter-genotype variation in size plasticity that is necessary for its evolution.

Significance Statement

The environmental conditions under which development takes place can affect developmental outcomes and lead to the production of phenotypes adjusted to the environment adults will live in. This developmental plasticity, which can help organisms cope with environmental heterogeneity, is heritable and under selection. Plasticity can itself evolve, a process that will be partly dependent on the available genetic variation for this trait. Using a wild-derivedD. melanogasterpanel, we identified DNA sequence variants associated to variation in thermal plasticity for body size. We found that these variants correspond to a diverse set of gene functions. Furthermore, their effects differ between body parts and properties of the thermal response, which can, therefore, evolve independently. Our results shed new light onto a number of key questions about the long discussed genes for plasticity.
Gene regulatory network analysis identifies sex-linked differences in colon cancer drug metabolism processes
Authors: Lopes-Ramos Camila M. , Kuijjer Marieke L. , Ogino Shuji , Fuchs Charles , DeMeo Dawn L. , Glass Kimberly , Quackenbush John
Published: March 2018

Significant sex differences are observed in colon cancer, and understanding these differences is essential to advance disease prevention, diagnosis, and treatment. Males have a higher risk of developing colon cancer and a lower survival rate than women. However, the molecular features that drive these sex differences are poorly understood. We used both transcript-based and gene regulatory network methods to analyze RNA-Seq data from The Cancer Genome Atlas for 445 patients with colon cancer. We compared gene expression between tumors in men and women and found no significant sex differences except for sex-chromosome genes. We then inferred patient-specific gene regulatory networks, and found significant regulatory differences between males and females, with drug and xenobiotics metabolism via cytochrome P450 pathways more strongly targeted in females. This finding was validated in a dataset that included 1,193 patients from five independent studies. While targeting of the drug metabolism pathway did not change the overall survival for males treated with adjuvant chemotherapy, females with greater targeting had an increase in 10-year overall survival probability, with 89% (95% CI: 78%-100%) survival compared to 61% (95% CI: 45%-82%) for women with lower targeting, respectively (p=0.034). Our network analysis uncovered patterns of transcriptional regulation that differentiate male and female colon cancer. Most importantly, targeting of the drug metabolism pathway was predictive of survival in women who received adjuvant chemotherapy. This network-based approach can be used to investigate the molecular features that drive sex differences in other cancers and complex diseases.
An afferent white matter pathway from the pulvinar to the amygdala facilitates fear recognition
Authors: McFadyen Jessica , Mattingley Jason B , Garrido Marta I
Published: March 2018

Our ability to rapidly detect threats is thought to be subserved by a subcortical pathway that quickly conveys visual information to the amygdala. This neural shortcut has been demonstrated in animals but has rarely been shown in the human brain. Importantly, it remains unclear whether such a pathway might influence neural activity and behaviour. We conducted a multimodal neuroimaging study of 622 participants from the Human Connectome Project. We applied probabilistic tractography to diffusion-weighted images, reconstructing a subcortical pathway to the amygdala from the superior colliculus via the pulvinar. We then computationally modelled the flow of neural activity during a face-viewing task and found evidence for a functionally-afferent pulvinar-amygdala pathway. Critically, individuals with greater fibre density in this pathway also had stronger dynamic coupling and enhanced fearful face recognition. Our findings provide converging evidence for the recruitment of an afferent subcortical pulvinar connection to the amygdala that facilitates fear recognition.
Limit distribution of the quartet balance index for Aldous’sβ≥ 0-model
Authors: Bartoszek Krzysztof
Published: March 2018

This paper builds up on T. Martínez-Coronado, A. Mir, F. Rossello and G. Valiente’s work “A balance index for phylogenetic trees based on quartets”, introducing a new balance index for trees. We show here that this balance index, in the case of Aldous’sβ≥ 0-model, convergences weakly to a distribution that can be characterized as the fixed point of a contraction operator on a class of distributions.
Effects of transcranial focused ultrasound on human primary motor cortex using 7T fMRI
Authors: Ai Leo , Bansal Priya , Mueller Jerel K. , Legon Wynn
Published: March 2018

Background

Transcranial focused ultrasound (tFUS) is a new non-invasive neuromodulation technique that uses mechanical energy to modulate neuronal excitability with high spatial precision. tFUS has been shown to be capable of modulating EEG brain activity in humans that is spatially restricted, and here, we use 7T MRI to extend these findings. We test the effect of tFUS on 7T BOLD fMRI signals from individual finger representations in the human primary motor cortex (M1) and connected cortical motor regions. Participants (N = 5) performed a cued finger tapping task in a 7T MRI scanner with their thumb, index, and middle fingers to produce a BOLD signal for individual M1 finger representations during either tFUS or sham neuromodulation to the thumb representation.

Results

Results demonstrated a statistically significant increase in activation volume of the M1 thumb representation for the tFUS condition as compared to sham. No differences in percent BOLD changes were found. This effect was spatially confined as the index and middle finger M1 finger representations did not show similar significant changes in either percent change or activation volume. No effects were seen during tFUS to M1 in the supplementary motor area (SMA) or the dorsal premotor cortex (PMd).

Conclusions

Single element tFUS can be paired with high field MRI that does not induce significant artifact. tFUS increases activation volumes of the targeted finger representation that is spatially restricted within M1 but does not extend to functionally connected motor regions.
Adenylosuccinate Lyase activity in the Purine recycling pathway is essential for developmental timing, germline maintenance and muscle integrity inC. elegans
Authors: Marsac Roxane , Pinson Benoît , Saint-Marc Christelle , Olmedo María , ArtalSanz Marta , Daignan-Fornier Bertrand , Gomes José-Eduardo
Published: March 2018

Purine homeostasis is ensured through a metabolic network widely conserved from prokaryotes to humans. Purines can either be synthesizedde novo, reused, or produced by interconversion of extant metabolites using the so-called recycling pathway. Although thoroughly characterized in microorganisms, such as yeast or bacteria, little is known about the regulation of this biosynthesis network in metazoans. In humans, several diseases are linked to purine biosynthesis deficiencies through yet poorly understood etiologies. Particularly, the deficiency in Adenylosuccinate Lyase (ADSL), one enzyme involved both in the purinede novoand recycling pathways, causes severe muscular and neuronal symptoms. In order to address the mechanisms underlying this deficiency, we establishedCaenorhabditis elegansas a metazoan model organism to study purine metabolism, while focusing on ADSL. We show that the purine biosynthesis network is functionally conserved inC. elegans. Moreover, ADSL is required for developmental timing and germline stem cell maintenance, and muscle integrity. Our results allow to ascribe developmental and tissue specific phenotypes to separable steps of the purine metabolic network in an animal model. Particularly, the muscle, germline and developmental defects are linked specifically to the ADSL role in the purine recycling pathway.
Distinct value encoding in striatal direct and indirect pathways during adaptive learning
Authors: Donahue Christopher H. , Liu Max , Kreitzer Anatol C.
Published: March 2018

The striatum is thought to play a central role in action selection and reinforcement, and optogenetic experiments suggest differential roles for direct- and indirect-pathway medium spiny neurons (dMSNs and iMSNs). However, the encoding of value-related information in dMSNs and iMSNs during adaptive decision-making is not well understood. We trained mice on a dynamic foraging task where they had to learn the value of different options based on their recent history of choices and outcomes. Single-cell calcium imaging in dorsomedial striatum revealed that dMSNs and iMSNs were oppositely modulated by the updated value of the different options. Additionally, we found that iMSNs were more active as animals slowed between trials, likely reflecting ongoing changes in motivational state. Together, our results demonstrate that co-activation of dMSNs and iMSNs during action initiation does not simply encode action identity, but instead reflects pathway-specific encoding of movement, motivation, and value information necessary for adaptive decision-making.
Comprehensive analysis of small RNA profile by massive parallel sequencing in HTLV-1 asymptomatic subjects with monoclonal and polyclonal rearrangement of the T-cell antigen receptor γ-chain
Authors: de Souza Daniela Raguer Valadão , Pessôa Rodrigo , Nukui Youko , Pereira Juliana , Casseb Jorge , de Oliveira Augusto César Penalva , Clissa Patricia Bianca , Sanabani Sabri Saeed
Published: March 2018

Introduction

In this study, we used a massive parallel sequencing technology to investigate the cellular small RNA (sRNA) operating in peripheral blood mononuclear cells (PBMCs) of the Human T-lymphotropic virus type I (HTLV-I) infected asymptomatic subjects with a monoclonal and polyclonal rearrangement of the T-cell antigen receptor γ-chain.

Materials and Methods

Blood samples from 15 HTLV-1 asymptomatic carriers who were tested for clonalTCR-γ gene (seven and eight subjects presented monoclonal and polyclonal expansion of HTLV-1 infected cells, respectively), and were submitted to Illumina for small RNA library construction. sRNA libraries were prepared from cryoperserved PBMCs using TrueSeq Small RNA Library Preparation Kit (Illumina). The sRNA-Seq reads were aligned, annotated, and profiled by different bioinformatics tools.

Results

Through bioinformatics analysis, we identified a total of 494 known sRNAs and 120 putative novel sRNAs. Twenty-two known and 15 novel sRNA showed a different expression (>2-fold) between the asymptomatic monoclonal (ASM) and asymptomatic polyclonal carriers (ASP). The hsa-mir-196a-5p was the most abundantly upregulated micro RNA (miRNA) and the hsa-mir-133a followed by hsa-mir-509-3p were significantly downregulated miRNAs with more than a three-fold difference in the ASM than ASP group. The target genes predicted to be regulated by the differentially expressed miRNAs play essential roles in diverse biological processes including cell proliferation, differentiation, and/or apoptosis.

Discussion

Our results provide an opportunity for a further understanding of sRNA regulation and function in HTLV-1 infected subjects with monoclonality evidence.
DeepQSM - Using Deep Learning to Solve the Dipole Inversion for MRI Susceptibility Mapping
Authors: Bøtker Rasmussen Kasper Gade , Kristensen Mads , Blendal Rasmus Guldhammer , Østergaard Lasse Riis , Plocharski Maciej , O’Brien Kieran , Langkammer Christian , Janke Andrew , Barth Markus , Bollmann Steffen
Published: March 2018

Quantitative susceptibility mapping (QSM) aims to extract the magnetic susceptibility of tissue from magnetic resonance imaging (MRI) phase measurements. The mapping of magnetic susceptibility in vivo has gained broad interest in several fields of science and medicine because it yields relevant information on biological tissue properties, predominantly myelin, iron and calcium. Thereby, QSM can also reveal pathological changes of these key components in devastating diseases such as Parkinson’s disease, Multiple Sclerosis, or hepatic iron overload. As QSM requires the solution of an ill-posed field-to-source-inversion, current techniques utilize manual optimization of regularization parameters to balance between smoothing, artifacts and quantification accuracy. We trained a fully convolutional deep neural network - DeepQSM - to invert the magnetic dipole kernel convolution. This network is capable of solving the ill-posed field-to-source inversion on real-world in vivo MRI phase data without the need for manual parameter tuning, which proves that this network has generalized the underlying mathematical principle of the dipole inversion. We demonstrate that DeepQSM’s susceptibility maps enable identification of deep brain substructures that are not visible in MRI phase data and provide information on their respective magnetic tissue properties. We illustrate DeepQSM’s clinical relevance in a patient with multiple sclerosis showing its sensitivity to white matter lesions. In summary, DeepQSM can be used to determine the composition of myelin sheets of nerve fibers in the brain, and to assess quantitative information on iron homeostasis and its dysregulation, and will subsequently contribute to a better understanding of these biological processes in health and disease.
Single-molecular and Ensemble-level Oscillations of Cyanobacterial Circadian Clock
Authors: Das Sumita , Terada Tomoki P. , Sasai Masaki
Published: March 2018

When three cyanobacterial proteins, KaiA, KaiB, and KaiC, are incubated with ATP in vitro, the phosphorylation level of KaiC hexamers shows stable oscillation with approximately 24 h period. In order to understand this KaiABC clockwork, we need to analyze both the macroscopic synchronization of a large number of KaiC hexamers and the microscopic reactions and structural changes in individual KaiC molecules. In the present paper, we explain two coarse-grained theoretical models, the many-molecule (MM) model and the single-molecule (SM) model, to bridge the gap between macroscopic and microscopic understandings. In the simulation results with these models, ATP hydrolysis drives oscillation of individual KaiC hexamers and ATP hydrolysis is necessary for synchronizing oscillations of a large number of KaiC hexamers. Sensitive temperature dependence of the lifetime of the ADP bound state in the CI domain of KaiC hexamers makes the oscillation period temperature insensitive. ATPase activity is correlated to the frequency of phosphorylation oscillation in the single molecule of KaiC hexamer, which should be the origin of the observed ensemble-level correlation between the ATPase activity and the frequency of phosphorylation oscillation. Thus, the simulation results with the MM and SM models suggest that ATP hydrolysis randomly occurring in each CI domain of individual KaiC hexamers is a key process for oscillatory behaviors of the ensemble of many KaiC hexamers.

Significance Statement

Cyanobacterial proteins, KaiA, KaiB, and KaiC, can reconstitute a circadian clock when they are incubated with ATP in vitro. In order to understand this prototypical oscillator, we need to analyze both synchronization of a macroscopically large number of oscillating molecules and microscopic reactions in individual molecules. We introduced two theoretical models to unify macroscopic and microscopic viewpoints. Simulation results suggest that ATP hydrolysis is necessary for synchronization and temperature compensation and that ATPase activity is correlated to the oscillation frequency in individual molecules. Thus, ATP hydrolysis randomly occurring in individual molecules should determine important features of the ensemble-level oscillation.
A Deep Predictive Coding Network for Learning Latent Representations
Authors: Dora Shirin , Pennartz Cyriel , Bohte Sander
Published: March 2018

It has been argued that the brain is a prediction machine that continuously learns how to make better predictions about the stimuli received from the external environment. It builds a model of the world around us and uses this model to infer the external stimulus. Predictive coding has been proposed as a mechanism through which the brain might be able to build such a model of the external environment. However, it is not clear how predictive coding can be used to build deep neural network models of the brain while complying with the architectural constraints imposed by the brain. In this paper, we describe an algorithm to build a deep generative model using predictive coding that can be used to infer latent representations about the stimuli received from external environment. Specifically, we used predictive coding to train a deep neural network on real-world images in a unsupervised learning paradigm. To understand the capacity of the network with regards to modeling the external environment, we studied the latent representations generated by the model on images of objects that are never presented to the model during training. Despite the novel features of these objects the model is able to infer the latent representations for them. Furthermore, the reconstructions of the original images obtained from these latent representations preserve the important details of these objects.
Time Dependent Stochastic mRNA and Protein Synthesis in Piecewise-deterministic Models of Gene Networks
Authors: Innocentini Guilherme C.P. , Hodgkinson Arran , Radulescu Ovidiu
Published: March 2018

We discuss piecewise-deterministic approximations of gene networks dynamics. These approximations capture in a simple way the stochasticity of gene expression and the propagation of expression noise in networks and circuits. By using partial omega expansions, piecewise deterministic approximations can be formally derived from the more commonly used Markov pure jump processes (chemical master equation). We are interested in time dependent multivariate distributions that describe the stochastic dynamics of the gene networks. This problem is difficult even in the simplified framework of piecewise-determinisitic processes. We consider three methods to compute these distributions: the direct Monte-Carlo, the numerical integration of the Liouville-master equation and the push-forward method. This approach is applied to multivariate fluctuations of gene expression, generated by gene circuits. We find that stochastic fluctuations of the proteome and much less those of the transcriptome can discriminate between various circuit topologies.
Comprehensive catalog of dendritically localized mRNA isoforms from sub-cellular sequencing of single mouse neurons
Authors: Middleton Sarah A. , Eberwine James , Kim Junhyong
Published: March 2018

RNA localization to neuronal dendrites is critical step for long-lasting synaptic potentiation, but there is little consensus regarding which RNAs are localized and the role of alternative isoforms in localization. Using independent RNA-sequencing from soma and dendrites of the same neuron, we deeply profiled the sub-cellular transcriptomes to assess the extent and variability of dendritic RNA localization in individual hippocampal neurons, including an assessment of differential localization of alternative 3’UTR isoforms. We identified 2,225 dendritic RNAs, including 298 cases of 3’UTR isoform-specific localization. We extensively analyzed the localized RNAs for potential localization motifs, finding that B1 and B2 SINE elements are up to 5.7 times more abundant in localized RNA 3’UTRs than non-localized, and also functionally characterized the localized RNAs using protein structure analysis. Finally, we integrate our list of localized RNAs with the literature to provide a comprehensive list of known dendritically localized RNAs as a resource.
Molecular structures of a series of substituted bis(η5-cyclopentadienyl)titanium dihalides Cp
R

2TiX
2 [X = F, Cl, Br and I; R = CHPh2, CH(p-Tol)2 and adamantyl]
Authors: Oswald Tim , Lauterbach Nicolai , Schmidtmann Marc , Beckhaus Rüdiger
Published: March 2018

Metallocene dihalides and derivatives thereof are of great interest as precursors for catalysts in polymerization reactions, as antitumor agents and, due to their increased stability, as suitable starting materials in salt metathesis reactions and the generation of metallocene fragments. We report the synthesis and structural characterization of a series of eleven substituted bis(η5-cyclopentadienyl)titanium dihalides, namely bis[η5-1-(diphenylmethyl)cyclopentadienyl]difluoridotitanium(IV), [Ti(C18H15)2F2], bis{η5-1-[bis(4-methylphenyl)methyl]cyclopentadienyl}difluoridotitanium(IV), [Ti(C20H19)2F2], and bis{η5-1-[bis(adamantan-2-yl)methyl]cyclopentadienyl}difluoridotitanium(IV), [Ti(C15H19)2F2], together with the bromide and iodide analogues, and the chloride analogues of the diphenylmethyl and adamantyl complexes. These eleven complexes were prepared by the reaction of the corresponding bis(η5:η1-pentafulvene)titanium complexes with different hydrogen halides (Cl, Br and I). The titanocene fluorides become available via chloride–fluoride exchange reactions.
Factors differentiating the level of crop insurance at Polish farms
Authors: Wąs Adam , Kobus Pawel
Published: March 2018

Purpose

The purpose of this paper is to identify the factors that determine demand for crop insurance in Poland.

Design/methodology/approach

To examine the determinants of decisions regarding crop insurance, the authors used logistic regression. The base source of data for the analysis was the 2013 FADN sample. The scale of yield losses, the indemnities received and the Arrow-Pratt risk aversion coefficient were examined in a representative sample of farms in consecutive years in the period 2004-2013.

Findings

Losses are the major determinants of crop insurance uptake. Additionally, it was observed that the economic determinants are in line with the expected utility theory, while contrary to expectations, farmer’s characteristics such as education level, age or even risk aversion did not prove to have any influence on crop insurance uptake.

Research limitations/implications

The FADN sample is representative as regards the type of farming, economic size of farm and location of the farm. Every farm in the sample represents a specific number of similar farms in the population. However, it must be emphasised that the representativeness of the sample with respect to other determinants, e.g., yield losses in previous years, using crop insurance or the farmers’ age and education has not been verified due to lack of data characterizing the general population with regard to these factors.

Practical implications

It could be argued that the system of crop insurance subsidies should be targeted to encourage the farmers who previously had not used insurance to join the system.

Originality/value

The paper presents the analysis of crop insurance uptake in a country with a strongly polarised agriculture. The Polish farm sector consists of 1.4 million farms with sizes ranging from 1 ha to over a few thousands hectares. The research is based on a data set of 5,202 farms which contains data from ten years (2004-2013). The novelty of the methodological approach is that it includes information on the number of farms represented by every farm in the FADN sample in the Horvitz-Thompson estimator in order to achieve results which are valid for the general population of Polish farms.
How do financially vulnerable farms finance debt in periods of falling prices?
Authors: Prager Daniel L. , Burns Christopher B. , Miller Noah J.
Published: March 2018

Purpose

The purpose of this paper is to examine the effect of falling commodity prices on farm debt usage of corn and soybean farms, and how this debt usage differs based on the financial leverage of the farm.

Design/methodology/approach

Using panel data on farms surveyed at least twice in the Agricultural Resource Management Survey (ARMS) from 1996 to 2015, this paper uses a difference-in-differences approach to measure the effect of low commodity price shocks on financially vulnerable farms. To account for the correlation in the error structure between the three dependent variables (real estate debt, non-real estate debt, and interest payments) we use a seemingly unrelated regression approach.

Findings

Following a commodity price shock, financially vulnerable farms (debt-to-asset ratio greater than 40 percent) were found to increase their non-real estate debt when compared with non-financially vulnerable farms. Off-farm business income was found to help farms reduce real estate debt and interest payments in the face of these shocks.

Research limitations/implications

Data consist of corn and soybean farms surveyed more than once in the ARMS from 1996 to 2015 and are not representative of all US farms, but have similar characteristics to US commercial farms.

Social implications

The results indicate that financially vulnerable commercial crop farms respond to lower prices by taking on non-real estate debt, increasing financial stress. Well-targeted federal programs could prevent further financial stress for this group.

Originality/value

This is the first paper to use unbalanced panel data from ARMS to examine how farm debt use responds to commodity prices. This paper can inform policymakers about the financial risks to farms resulting from the current low-price environment.
Social media as tool for facilitating knowledge creation and innovation in small and medium enterprises
Authors: Papa Armando , Santoro Gabriele , Tirabeni Lia , Monge Filippo
Published: March 2018

Purpose

The purpose of this paper is to study the effects of social media usage on four knowledge creation processes, namely socialisation, externalisation, combination and internalisation, and innovation in small and medium enterprises (SMEs).

Design/methodology/approach

A sample of 96 SMEs has been used to gather data through a standardised questionnaire and test the hypotheses through OLS regression models.

Findings

The results indicate that social media influence positively three out of four knowledge creation processes and that they help to foster the innovation process.

Originality/value

From a theoretical perspective, the study contributes to literature considering a specific digital tool and its effect on knowledge creation and innovation. In fact, a few studies have considered the impact of social media usage on other variables, such as ROI and productivity, but never on knowledge creation and innovation through a quantitative study. From a managerial perspective, the research suggests managers to implement and involve social media within business and innovation processes.
Expanding horizons and expatriate adjustment
Authors: Tahir Rizwan
Published: March 2018

Purpose

Expatriate management is a popular theme in the field of international human resource management in light of the fact that expatriates play a crucial role in a MNC’s global operations. The purpose of this paper is to explore how MNCs select, train, deploy and support expatriate managers during and after their international assignment in the United Arab Emirates (UAE).

Design/methodology/approach

This qualitative study is based on in-depth interviews with 22 Western expatriate managers who are presently based in the UAE. However, in order the ensure a diverse sample among the participants with regards to their age, professional experience, gender and nationality, purposeful sampling was utilized while selecting the participants.

Findings

The results of the present study cast light on many shortcomings of the overall expatriation process as they are implemented by MNCs in the UAE. Accordingly, there is a pressing need for MNCs in the UAE to develop strategic expatriation processes, involving the following critical factors: the selection of the right person for the right job; specific and relevant pre-departure and post-arrival cross-cultural training (CCT); practical support for the expatriate employees and their trailing spouses in the host country; and lastly, a clear repatriation strategy to mark a successful conclusion of foreign assignments in the UAE.

Research limitations/implications

It is acknowledged that the results of this purely qualitative study, based on a relatively small sample size, cannot claim to represent the management theories, practices and realities of all the Western MNCs in the UAE. Moreover, these findings narrate the views and perceptions of this particular cohort of expatriate executives with relation to their selection, pre-departure CCT, adjustment in the UAE and the support and repatriation policies utilized by their companies for doing business in the UAE.

Practical implications

This study points to the fact that technical skills are mostly considered to be the predominant selection criteria for the expatriate selections in the MNCs. Other abilities, such as language skills and relational and perceptual adjustability are considered to be less important and do not feature overtly in the selection criteria for expatriate positions. The results demonstrate that distinctive features of adjustability, which include expatriates’ willingness to communicate, their social orientation, dynamic anxiety resistance and openness ability are all critical to the adjustment in the host country and should be given more emphasis.

Originality/value

Regardless of the presence of numerous MNCs in the UAE, it is indeed surprising to see that the topic of the expatriation management process in MNCs in the UAE has received little research attention. The objective of this study is to address this deficiency. Additionally, it is hoped that these findings may also be valuable to MNCs and consultants who are preparing expatriates for international assignments, especially in the Middle East and in particular in the UAE.
The effects of association strength on attention and product evaluation
Authors: Chang Yonghwan , Ko Yong Jae
Published: March 2018

Purpose

The purpose of this study was to test whether endorsements that show a low strength of association (bottom-up bias) benefit from increased attention and processing efforts. The current study also tested whether consumer involvement level (top-down bias) dynamically interacts with the bottom-up attention phenomena.

Design/methodology/approach

Through a series of pretests, 36 potential celebrity-product matches were identified using real athletes and product brands. Two experiments were conducted: 330 individual responses (110 participants × three conditions) were obtained in a within-subjects lab experiment, and 868 participants were recruited for a between-subjects online experiment. Linear mixed modeling and moderated mediation analysis were performed.

Findings

The relationships between the strength of image associations and attention time to endorsements and recall and choice consideration of endorsed brands were U-shaped and curvilinear. Attention largely mediated the relationship between the strength of association and recall/choice. Involvement effects were diluted by the strength of association effects, rejecting top-down attentional control.

Practical implications

Brand managers for both products and celebrities are recommended to search for corresponding not only image-matched partners but also endorsement partners with dissonant pre-existing images.

Originality/value

The majority of the existing endorsement literature has conventionally suggested that congruence between the endorser and the endorsed property, rather than incongruence, induces consumers’ positive endorsement evaluation. This study constructs important theoretical advancements to the existing literature by empirically proving that through an attentional process, an endorsement contract, conventionally perceived as mismatched, can also generate positive outcomes.