bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diffusion MRI monitoring of specific structures in the irradiated rat brain
Authors: Constanzo Julie , Dumont Matthieu , Lebel Réjean , Tremblay Luc , Whittingstall Kevin , Masson‐Côté Laurence , Geha Sameh , Sarret Philippe , Lepage Martin , Paquette Benoit , Descoteaux Maxime 
Published: February 2018

PurposeThe analysis of biological and mesoscopic structures properties by diffusion MRI (dMRI) in brain after radiation therapy remains challenging. In our study, we described the consequences associated with an unwanted dose to healthy tissue, assessing radiation‐induced brain alterations of living rats with dMRI compared to histopathology and behavioral assays.MethodsThe right primary motor cortex M1 of the rat brain was targeted by stereotactic radiosurgery with a mean radiation dose of 41 Gy. Multidirectional single b‐value dMRI data of the whole brain were acquired with a 7T small‐animal scanner before irradiation until 110 days post‐irradiation. Diffusion tensor imaging metrics, such as fractional anisotropy (FA), mean diffusivity (MD), axial (AD), and radial diffusivity (RD) were compared to brain alterations detected by immunohistochemistry and motor performances measured by a behavioral test.ResultsBetween days 90 and 110, radiation necrosis was observed into the white matter spreading into M1. Results showed a reduction of FA in the corpus callosum and in the striatum, which was driven by an increase in RD from 90 to 110 days post‐irradiation, whereas only RD increased in M1. Values of RD and AD increased in the irradiated hippocampus, while FA remained constant. Moreover, an increased MD, AD and RD was observed in the hippocampus that was probably related to inflammation as well as reactive astrogliosis after 110 days post‐irradiation. Finally, rats did not exhibit locomotor deficits.ConclusionsdMRI metrics can assess brain damage; the sensitivity of dMRI metrics depends on the brain region.
Simultaneous multislice refocusing via time optimal control
Authors: Rund Armin , Aigner Christoph Stefan , Kunisch Karl , Stollberger Rudolf 
Published: February 2018

PurposeJoint design of minimum duration RF pulses and slice‐selective gradient shapes for MRI via time optimal control with strict physical constraints, and its application to simultaneous multislice imaging.Theory and MethodsThe minimization of the pulse duration is cast as a time optimal control problem with inequality constraints describing the refocusing quality and physical constraints. It is solved with a bilevel method, where the pulse length is minimized in the upper level, and the constraints are satisfied in the lower level. To address the inherent nonconvexity of the optimization problem, the upper level is enhanced with new heuristics for finding a near global optimizer based on a second optimization problem.ResultsA large set of optimized examples shows an average temporal reduction of 87.1% for double diffusion and 74% for turbo spin echo pulses compared to power independent number of slices pulses. The optimized results are validated on a 3T scanner with phantom measurements.ConclusionThe presented design method computes minimum duration RF pulse and slice‐selective gradient shapes subject to physical constraints. The shorter pulse duration can be used to decrease the effective echo time in existing echo‐planar imaging or echo spacing in turbo spin echo sequences.
An 8/15‐channel Tx/Rx head neck RF coil combination with region‐specific B1+ shimming for whole‐brain MRI focused on the cerebellum at 7T
Authors: Pfaffenrot Viktor , Brunheim Sascha , Rietsch Stefan H. G. , Koopmans Peter J. , Ernst Thomas M. , Kraff Oliver , Orzada Stephan , Quick Harald H. 
Published: February 2018

PurposeTo design and evaluate an 8/15‐channel transmit/receive (Tx/Rx) head‐neck RF coil combination with region‐specific
shimming for whole‐brain MRI with focus on improved functional MRI of the cerebellum at 7 T.MethodsAn 8‐channel transceiver RF head coil was combined with a 7‐channel receive‐only array. The noise parameters and acceleration capabilities of this 8Tx/15Rx coil setup were compared with a commercially available 1Tx/32Rx RF head coil. Region‐specific 8‐channel
shimming was applied when using the 8Tx/15Rx RF coil. To evaluate the capability for functional MRI of the cerebellum, temporal SNR and statistical nonparametric maps for finger‐tapping experiments with 14 healthy subjects were derived by applying a variable slice thickness gradient‐echo echo‐planar functional MRI sequence.ResultsThe 8Tx/15Rx setup had a lower maximum noise correlation between channels, but higher average correlations compared with the 1Tx/32Rx coil. Both RF coils exhibited identical g‐factors in the cerebellum with R = 3 acceleration. The enlarged FOV of the 8Tx/15Rx coil in combination with region‐specific
shimming increased homogeneity of the transmission field and temporal SNR in caudal cerebellar regions. Temporal SNR losses in cranial parts were reduced, resulting in more highly significant voxels in the caudally activated areas and identical patterns in the cranial cerebellar parts during a finger‐tapping task.ConclusionCompared with the 1Tx/32Rx RF coil, the presented 8Tx/15Rx RF coil combination successfully improves functional MRI of the human cerebellum at 7 T while maintaining whole‐brain coverage. A clear temporal SNR gain in caudal cerebellar regions is shown.
Simultaneous multislice acquisition without trajectory modification for hyperpolarized 13C experiments
Authors: Lau Angus Z. , Lau Justin Y. C. , Chen Albert P. , Cunningham Charles H. 
Published: February 2018

PurposeTo investigate the feasibility of performing large FOV hyperpolarized 13C metabolic imaging using simultaneous multislice excitation.MethodsA spectral‐spatial multislice excitation pulse was constructed by cosine modulation and incorporated into a 13C spiral imaging sequence. Phantom and in vivo pig experiments were performed to test the feasibility of simultaneous multislice data acquisition and image reconstruction. In vivo cardiac‐gated images of hyperpolarized pyruvate, bicarbonate, and lactate were obtained at 1 × 1 × 1 cm3 resolution over a 48 × 48 × 24 cm3 FOV with 2‐fold acceleration in the slice direction. Sensitivity encoding was used for image reconstruction with both autocalibrated and numerically calculated coil sensitivities.ResultsSimultaneous multislice images obtained with 2‐fold acceleration were comparable to reference unaccelerated images. Retained SNR figures greater than 80% were achieved over the part of the image containing the heart.ConclusionThis method is anticipated to enable large FOV imaging studies using hyperpolarized 13C substrates, with an aim toward whole‐body exams that have to date been out of reach.
Demographic features of female urethra length
Authors: Pomian Andrzej , Majkusiak Wojciech , Kociszewski Jacek , Tomasik Paweł , Horosz Edyta , Zwierzchowska Aneta , Lisik Wojciech , Barcz Ewa 
Published: February 2018

AimsTo determine cohort urethral length, identify epidemiological factors influencing the parameter and to establish the percentage of cases with clinically relevant outsized urethras.MethodsProspective cohort study conducted in two tertiary clinical centers between 2013 and 2017. Nine hundred and twenty seven consecutive adult, Caucasian females attending outpatients’ clinics were included. The urethral length has been measured in pelvic floor ultrasound examination. The exclusion criteria were inadequate bladder filling (<200 mL; >400 mL), previous history of pelvic floor surgery, and no consent.ResultsUrethral length varied from 19 to 45 mm. The distribution of the examined parameter was normal. Obese patients had significantly longer urethras as compared to non‐obese subjects. Number of vaginal deliveries was connected with shorter urethral length. The limitations of the study are: analysis only of Caucasian patients and subjects without previous pelvic floor surgeries.ConclusionsDifferences in urethral length in the female population were demonstrated. Thirty percent of patients have atypical urethras that may be a risk factor for sling surgery failure. We therefore postulate introduction of urethral measurement before the procedure.
The role of the mucosa in modulation of evoked responses in the spinal cord injured rat bladder
Authors: Doyle Claire , Cristofaro Vivian , Sack Bryan S. , Mahmood Fabliha , Sullivan Maryrose P. , Adam Rosalyn M. 
Published: February 2018

AimsMounting evidence indicates that a variety of factors released from the urothelium or suburothelium can modulate smooth muscle activity. Although the relationship between the mucosa and smooth muscle has been investigated, little is known about the pathophysiologic changes in detrusor‐mucosa interactions in neurogenic bladders. The goal of the study was to determine the impact of the mucosa on evoked responses in spinal cord injured (SCI) bladders.MethodsUrinary bladders were obtained from 6wk SCI rats or age‐matched uninjured controls. Ex vivo isometric tension studies were performed and muscarinic receptor expression was measured in bladder tissue with and without mucosa.ResultsThe magnitude and area of nerve evoked responses in SCI tissue with mucosa was higher than without mucosa. The duration and decay time of nerve‐evoked responses were longer in SCI than control tissue irrespective of the mucosa. The level of the muscarinic M2 receptor was decreased in the mucosa of SCI bladders.ConclusionsDetrusor‐mucosa interactions are substantially altered in the neurogenic bladder. After spinal cord injury, an excitatory modulation of smooth muscle contraction by the mucosa emerges, and could be targeted via intravesical treatment in the context of neurogenic bladder dysfunction.
Weight Stigma Predicts Poorer Psychological Well‐Being Through Internalized Weight Bias and Maladaptive Coping Responses
Authors: Hayward Lydia E. , Vartanian Lenny R. , Pinkus Rebecca T. 
Published: February 2018

ObjectiveWeight‐based stigmatization is associated with negative psychological and behavioral consequences, but individuals respond to stigma in different ways. The present study aimed to understand some of the factors that predict how one will cope with weight stigma and how different coping responses predict psychological well‐being.MethodsAcross four samples, 1,391 individuals who identified as having overweight or obesity completed surveys assessing the frequency of weight stigma experiences, internalized weight bias, coping responses to weight stigma, and psychological distress.ResultsFrequency of weight stigma predicted greater internalized weight bias, which predicted more frequent use of maladaptive coping responses (“disengagement coping”) and less frequent use of adaptive coping responses (“reappraisal coping”), in turn predicting more depression, anxiety, and stress symptoms.ConclusionsThe more that individuals with overweight or obesity experience weight stigma and internalize weight bias, the more they report using maladaptive coping and the less they report using adaptive coping when dealing with weight stigma. Maladaptive coping is strongly associated with poorer psychological well‐being. Thus, those who experience more frequent weight stigma may be more vulnerable to psychological distress because they appear to be at greater risk of employing maladaptive coping strategies.
Longitudinal Increases in Adiposity Contribute to Worsening Adipokine Profile over Time in Mexican Americans
Authors: Black Mary Helen , Shu Yu‐Hsiang , Wu Jun , Koebnick Corinna , MacKay Adrienne , Watanabe Richard M. , Buchanan Thomas A. , Xiang Anny H. 
Published: February 2018

ObjectiveLimited studies have assessed the relationship between longitudinal changes in adiposity and changes in multiple adipokines over time. This study examined changes in BMI, total body fat, and trunk fat associated with changes in 16 circulating adipokines in Mexican Americans at risk for type 2 diabetes.MethodsParticipants included 1,213 individuals with cross‐sectional data and a subset of 368 individuals with follow‐up measures (mean 4.6 ± 1.5 years from baseline). Joint multivariate associations between 3 adiposity measures and 16 adipokines were assessed by canonical correlation analysis.ResultsLongitudinal increases in adiposity were most strongly associated with increasing leptin, C‐reactive protein (CRP), and interleukin 1 receptor antagonist (IL‐1Ra) and decreasing adiponectin and secreted frizzled protein 5 (SFRP5) over time. Participants with BMI ≥ 30 kg/m2 at baseline had greater increases in leptin, CRP, IL‐1Ra, and interleukin 6 (IL‐6) and greater decreases in adiponectin and SFRP5, associated with increasing adiposity over follow‐up, than those with BMI < 30 kg/m2. Associations between adiposity and adipokines were most accounted for by leptin; adjustment for leptin greatly reduced the magnitude of all associations between adiposity and remaining adipokines.ConclusionsIncreasing adiposity contributes to a worsening imbalance of pro‐ and anti‐inflammatory adipokines over time, in which leptin may have an important role as a key mediator of metabolic disease risk in Mexican Americans.
Peptide therapeutics that directly target transcription factors
Authors: Inamoto Ichiro , Shin Jumi A. 
Published: February 2018

AbstractTranscription factors regulate gene expression in cells and control cellular development, function, and death. Dysregulation of transcription factors is often associated with disease, including cancer. As such, transcription factors are attractive targets for design of therapeutics against disease. Transcription factors function using protein‐protein and protein‐DNA interactions that occur over relatively large surface areas: this lack of a small and defined “ligand binding site” has proven to be challenging to target with small molecules. Peptide therapeutics, therefore, provide an alternate approach toward design of inhibitory agents. Transcription factors are conveniently modular by design: just the small domain that is responsible for the transcription factor's DNA binding or a protein‐protein interaction or another function, can serve as the basis for novel peptide therapeutics. In this review, examples of peptides that directly interfere with transcription factors will be discussed.
Meropenem and Vaborbactam: Stepping up the Battle against Carbapenem‐resistant Enterobacteriaceae
Authors: Jorgensen Sarah Christina Jane , Rybak Michael Joseph 
Published: February 2018

Vaborbactam (VAB; formerly RPX7009) is a novel beta‐lactamase inhibitor based on a cyclic boronic acid pharmacophore with potent inhibitory activity against Ambler class A and C beta‐lactamases. It has been co‐formulated with meropenem to restore its activity against Klebsiella pneumoniae carbapenemases (KPC). VAB does not inhibit class B or D carbapenemases, nor does it improve the activity of meropenem against multidrug‐resistant nonfermenting gram‐negative bacilli, notably Acinetobacter spp. and Pseudomonas aeruginosa. The purpose of this article is to review existing data pertaining to the biochemistry, mechanism of action, pharmacokinetics/pharmacodynamics, in vitro activity, and current progress in clinical trials of meropenem and VAB (MV). Phase 1 studies have demonstrated single and multiple doses of VAB up to 2000 mg, alone or in combination with meropenem 2000 mg administered as a prolonged infusion over 3 hours, are well tolerated with an adverse effect profile similar to that of meropenem monotherapy. The available data suggest preexisting resistance among KPC‐producing isolates is rare. Strains with elevated MICs have been characterized by multiple resistance determinants including porin defects, increased drug efflux, and increased blaKPC expression. It remains uncertain whether multifactorial resistance will emerge during MV treatment and with more widespread use. Early data are positive for complicated urinary tract infections and MV compared with best available therapy in patients with serious carbapenem‐resistant Enterobacteriaciae (CRE) infections. As clinicians contemplate how to incorporate MV into CRE treatment strategies, it will be important to track and understand resistance, discern the role, if any, of combination therapy in enhancing efficacy and/or preserving activity, and define the specific therapeutic niche of MV among the expanding anti‐CRE armamentarium.
Dispersion of carbon nanotubes in ultrahigh‐molecular‐weight polyethylene by melt mixing dominated by elongation stress
Authors: Xiaochun Yin , Yang Li , Guangjian He , Yanhong Feng , Jingsong Wen 
Published: February 2018

AbstractA novel melt‐mixing method and corresponding mixer for polymer materials are reported. The effects of carbon nanotube (CNT) loading, rotation rate and mixing time on the morphology and properties of CNTs/ultrahigh‐molecular‐weight polyethylene (UHMWPE) nanocomposites were experimentally investigated in detail using the mixer. Homogeneous dispersion of CNTs in intractable UHMWPE is successfully realized without the aid of any additives or solvents. Differential scanning calorimetry results showed that the crystallinity increases 13.8% when 1 wt% of CNTs is added into the composites. The maximum crystallinity increased 13.5% and then decreased slightly with increasing rotation rate. The mixing time had little effect on crystallinity. Rheological tests reveal that the effect of CNT loading on the storage modulus/complex viscosity is a result of competition between the viscosity decrease due to the selective adsorption of UHMWPE onto CNT surfaces and the viscosity increase caused by the formation of an interconnected polymer–nanotube network. The storage modulus/complex viscosity decreased with increasing rotation rate/mixing time. This is a synergic result of the selective adsorption of the long molecular chains onto the CNT surface and their thermomechanical degradation. The results showed that the mixing process dominated by elongation stress is a simple, efficient green way to prepare CNTs/UHMWPE nanocomposites via melt mixing. © 2018 Society of Chemical Industry
Effects of crosslinking agents on the physical properties of polyimide/amino‐functionalized graphene oxide hybrid films
Authors: Jeong Keuk‐Min , Li Yuheng , Yoo Dae‐Geon , Lee Nam‐Kyoung , Lee Hyeok‐Gi , Ando Shinji , Ha Chang‐Sik 
Published: February 2018

AbstractThe effects of crosslinking agents (crosslinkers) on polyimide (PI)/graphene oxide (GO) hybrid films were extensively investigated. The surface of GO was modified with amino groups using 4‐aminobenzylamine to improve compatibility with pyromellitic dianhydride/4,4′‐oxydianiline PI, and two kinds of crosslinkers were used: tris(4‐aminophenyl)amine and 1,3,5‐triazine‐2,4,6‐triamine (melamine). The mechanical, thermal and optical properties of the PI hybrid films were investigated. In particular, the transparency and physical properties of the PI hybrid films containing amino‐functionalized GO with homogeneous dispersion were improved. As the content of the crosslinker increased, a crosslinking network was formed between the PI chains, and the stiffness of the hybrid films was increased. The glass transition temperature, heat resistance and mechanical properties were also enhanced. The PI hybrids prepared with a rigid crosslinker exhibited higher optical transparency due to the reduction of the intermolecular charge transfer interactions with increasing interchain spacing between the PI chains. © 2018 Society of Chemical Industry
Comparing side chain packing in soluble proteins, protein‐protein interfaces, and transmembrane proteins
Authors: Gaines J. C. , Acebes S. , Virrueta A. , Butler M. , Regan L. , O'Hern C. S. 
Published: February 2018

AbstractWe compare side chain prediction and packing of core and non‐core regions of soluble proteins, protein‐protein interfaces, and transmembrane proteins. We first identified or created comparable databases of high‐resolution crystal structures of these 3 protein classes. We show that the solvent‐inaccessible cores of the 3 classes of proteins are equally densely packed. As a result, the side chains of core residues at protein‐protein interfaces and in the membrane‐exposed regions of transmembrane proteins can be predicted by the hard‐sphere plus stereochemical constraint model with the same high prediction accuracies (>90%) as core residues in soluble proteins. We also find that for all 3 classes of proteins, as one moves away from the solvent‐inaccessible core, the packing fraction decreases as the solvent accessibility increases. However, the side chain predictability remains high (80% within
) up to a relative solvent accessibility,
, for all 3 protein classes. Our results show that
% of the interface regions in protein complexes are “core”, that is, densely packed with side chain conformations that can be accurately predicted using the hard‐sphere model. We propose packing fraction as a metric that can be used to distinguish real protein‐protein interactions from designed, non‐binding, decoys. Our results also show that cores of membrane proteins are the same as cores of soluble proteins. Thus, the computational methods we are developing for the analysis of the effect of hydrophobic core mutations in soluble proteins will be equally applicable to analyses of mutations in membrane proteins.
Minimum explosible concentrations of mist and dust clouds
Authors: Britton Laurence G. , Harrison Benjamin Keith 
Published: February 2018

When hot vapor condenses the nucleation particles initially formed coalesce rapidly and exothermically. Most of the heat of coalescence is released in less than a millisecond while droplets are less than 100 nm diameter. Consequently, the heat is released close to the source of the vapor and has no effect on dispersion. Coagulation rate is governed by an inverse square law with respect to number density; calculations showed that a vapor cloud initially within its flammable range should produce droplets smaller than 10 µm after a minute of coalescence. Such micronized droplets completely vaporize in flame preheat zones and behave as premixed vapors rather than as individual droplets; this characteristic is not due to the increased surface energy accompanying subdivision into micronized droplets but to short evaporation times in the thick preheat zones of limit flames. Droplet growth time is a nonlinear function of cloud mass concentration and if the latter exceeds about 10 times the minimum explosible concentration (MEC), droplets quickly grow to above 20–40 µm. These larger droplets tend to burn individually and the estimation of MEC becomes complicated, although rain‐out of large droplets might hasten dispersal to below the MEC.With the assumption that micronized crystalline organic materials behave similarly to liquid droplets, we derive “intrinsic” MEC values for both hydrocarbons and a series of CHOxfuels having increasing O:C ratios. In each case, the MEC attains a constant “terminal value” as carbon number is increased. Terminal MEC values are 40 g m−3for CH (hydrocarbons), 50 g m−3for CHO (aldehydes, ethers, etc.), 60 g m−3for CHOO (esters), 67 g m−3(polyethylene glycols), and 103 g m−3(carbohydrates). MEC values for CHO and CHOO decrease rapidly with increased carbon number since additional hydrocarbon units dilute the functional oxygen group. For polyethylene glycols and carbohydrates, the MEC is less dependent on carbon number since oxygen is contained in a repeating group. Although scission and/or decomposition replace simple evaporation as carbon number increases, flash pyrolysis data for polyethylene in air show that the products of decomposition can have little effect on MEC. Nevertheless, owing to experimental deficiencies published MEC values for polyethylene are as low as 10–30 g m−3. Of the many factors affecting MEC tests, we focus on the effects of gravity and flame radiation. Radiation not only affects MEC but also the burning rates of metal dusts such as titanium; such tests should be carried out on an adequately large scale. © 2017 American Institute of Chemical Engineers Process Process Saf Prog 37:4–17, 2018