bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanofiber‐Based Hydrogels: Controllable Synthesis and Multifunctional Applications
Authors: Fu Qiuxia , Duan Cheng , Yan Zishuo , Li Yan , Si Yang , Liu Lifang , Yu Jianyong , Ding Bin
Published: April 2018

Nanofiber‐based hydrogels (NFHGs) prepared by the combination of traditional hydrogels and novel nanofibers have demonstrated great potential in various application fields, owing to their integrated advantages of superhydrophilicity, high water‐holding capacity, good biocompatibility, enhanced mechanical strength, and excellent structural tenability. In this review, a comprehensive overview of the structure design and synthetic strategy of NFHGs derived from electrospinning technique, weaving, freeze‐drying, 3D printing, and molecular self‐assembling method is provided. The widely researched multifunctional applications, primarily involving tissue engineering, drug delivery, sensing, intelligent actuator, and oil/water separation are also presented. Furthermore, some unsolved scientific issues and possible directions for future development of this field are also intensively discussed.
Structure–Property Relations in New Cyclic Galactaric Acid Derived Monomers and Polymers Therefrom: Possibilities and Challenges
Authors: Wróblewska Aleksandra A. , Noordijk Jurrie , Das Nick , Gerards Chris , De Wildeman Stefaan M. A. , Bernaerts Katrien V.
Published: April 2018

In order to fully exploit the potential of carbohydrate‐based monomers, different (and some new) functionalities are introduced on galactaric acid via acetalization, and subsequently, partially‐biobased polyamides are prepared therefrom via polycondensation in the melt. Compared to nonsubstituted linear monomer, faster advancement of the reaction is observed for the different biacetal derivatives of galactaric acid. This kinetic observation is of great significance since it allows conducting a polymerization reaction at lower temperatures than normally expected for polyamides, which allows overcoming typical challenges (e.g., thermal degradation) encountered upon polymerization of carbohydrate‐derived monomers in the melt. The polymers derived from the modified galactaric acid monomers vary in terms of glass transition temperature, thermal stability, hydrophilicity, and functionality.
Self‐Assembly of Rod‐Coil Block Copolymers on Carbon Nanotubes: A Route toward Diverse Surface Nanostructures
Authors: Han Yang , Cai Chunhua , Lin Jiaping , Gong Shuting , Xu Wenheng , Hu Rui
Published: April 2018

In this work, it is reported that poly(γ‐benzyl‐l‐glutamate)‐block‐poly(ethylene glycol) (PBLG‐b‐PEG) rod‐coil block copolymers (BCPs) can disperse carbon nanotubes (CNTs) in solution and form various surface nanostructures on the CNTs via solution self‐assembly. In an organic solvent that dissolves the BCPs, the PBLG rod blocks adsorb on CNT surfaces, and the BCPs form conformal coatings. Then, by the introduction of water, a selective solvent for PEG blocks, the BCPs in the coatings further self‐assemble into diverse surface nanostructures, such as helices (left‐handed or right‐handed), gyros, spheres, and rings. The morphology of the surface nanostructure can be tailored by initial organic solvent composition, preparation temperature, feeding ratio of BCPs to CNTs, degree of polymerization of PBLG blocks, and diameter of the CNTs.
Picophytoplankton size and biomass around equatorial eastern Indian Ocean
Authors: Wei Yuqiu , Sun Jun , Zhang Xiaodong , Wang Jing , Huang Ke
Published: April 2018

The cellular size and biomass of picophytoplankton were studied by flow cytometer during spring monsoon (March–May of 2015) in equatorial eastern Indian Ocean. We established an empirical relationship between forward scatter and cellular size to address the size and biomass of picophytoplankton. Results indicated that mean cell diameter of Prochlorococcus (0.60 μm) was the smallest, and then followed by Synechococcus (0.98 μm) and picoeukaryotic phytoplankton (1.05 μm). Thereafter, the biomass converted by abundance reached 0.64 μg·C·L−1 for Prochlorococcus, 0.34 μg·C·L−1 for Synechococcus, and 0.20 μg·C·L−1 for picoeukaryotic phytoplankton. Additionally, the distinct biomass contribution of picophytoplankton appeared to be affected by abundance, but not changes in cellular size. Vertically, the cellular sizes of picophytoplankton were remarkably small in upper waters, which was predominantly controlled by the nutrient availability. In contrast, they were larger in deeper waters, which was primarily attributed to the combined effects of low temperature and reduced light availability. Spatially, under the influence of high nutrient concentration induced by the different circulations and coastal upwelling, slightly high carbon biomass of picophytoplankton was observed around the coastal zones of Sri Lanka island and Sumatra, as well as the southern Bay of Bengal.
Culture‐independent analysis of hydrocarbonoclastic bacterial communities in environmental samples during oil‐bioremediation
Authors: Dashti Narjes , Ali Nedaa , Salamah Samar , Khanafer Majida , Al‐Shamy Ghada , Al‐Awadhi Husain , Radwan Samir S.
Published: April 2018

To analyze microbial communities in environmental samples, this study combined Denaturing Gradient Gel Electrophoresis of amplified 16S rRNA‐genes in total genomic DNA extracts from those samples with gene sequencing. The environmental samples studied were oily seawater and soil samples, that had been bioaugmented with natural materials rich in hydrocarbonoclastic bacteria. This molecular approach revealed much more diverse bacterial taxa than the culture‐dependent method we had used in an earlier study for the analysis of the same samples. The study described the dynamics of bacterial communities during bioremediation. The main limitation associated with this molecular approach, namely of not distinguishing hydrocarbonoclastic taxa from others, was overcome by consulting the literature for the hydrocarbonoclastic potential of taxa related to those identified in this study. By doing so, it was concluded that the hydrocarbonoclastic bacterial taxa were much more diverse than those captured by the culture‐dependent approach. The molecular analysis also revealed the frequent occurrence of nifH‐genes in the total genomic DNA extracts of all the studied environmental samples, which reflects a nitrogen‐fixation potential. Nitrogen fertilization is long known to enhance microbial oil‐bioremediation. The study revealed that bioaugmentation using plant rhizospheres or soil with long history of oil‐pollution was more effective in oil‐removal in the desert soil than in seawater microcosms.
Construction and application of a Xanthomonas campestris CGMCC15155 strain that produces white xanthan gum
Authors: Dai Xiaohui , Gao Ge , Wu Mengmeng , Wei Weiying , Qu Jianmei , Li Guoqiang , Ma Ting
Published: April 2018

In the industrial production of xanthan gum using Xanthomonas campestris CGMCC15155, large amounts of ethanol are required to extract xanthan gum from the fermentation broth and remove xanthomonadin impurities. To reduce the amount of ethanol and the overall production cost of xanthan gum, a xanthomonadin‐deficient strain of CGMCC15155 was constructed by inserting the Vitreoscilla globin (vgb) gene, under the control of the LacZ promoter, into the region of the pigA gene, which is involved in xanthomonadin synthesis. The insertion of vgb inactivated pigA, resulting in the production of white xanthan gum. The lack of xanthomonadins resulted in a decreased yield of xanthan gum. However, the expression product of vgb gene, VHb, could increase the metabolism of X. campestris, which allowed the production of xanthan gum to reach wild‐type levels in the engineered strain. The yield, molecular weight, and rheological properties of the xanthan gum synthesized by the engineered and wild‐type bacteria were essentially the same. When the same volume of ethanol was used, the whiteness values of the xanthan gum extracted from engineered and wild‐type bacteria were 65.20 and 38.17, respectively. To extract xanthan gum with the same whiteness, three and seven times the fermentation volume of ethanol was required for the engineered and wild‐type strains, respectively. Thus, the engineered train reduced the requirement for ethanol in xanthan gum production by 133.3%. The results demonstrated that the engineered bacteria used less ethanol, thus reducing the downstream processing cost in xanthan gum production.
A nationwide analysis of 30‐day adverse events, unplanned readmission, and length of hospital stay after peripheral nerve surgery in extremities and the brachial plexus
Authors: Martin Enrico , Muskens Ivo S. , Senders Joeky T. , Cote David J. , Smith Timothy R. , Broekman Marike L. D.
Published: April 2018

Background

Little is known on adverse events and their timing after peripheral nerve surgery in extremities. The aim of this study is to identify predictors and typical timing of complications, unplanned readmission, and length of hospital stay for patients undergoing peripheral nerve surgery in the extremities.

Methods

Data were extracted from the National Surgical Quality Improvement Program (NSQIP) registry from 2005 to 2015. Adult patients undergoing peripheral nerve surgery in the extremities were included. A subgroup analysis was performed for brachial plexus operations. Multivariable logistic regression was performed to identify predictors of any complication, surgical site infection, unplanned readmission, and reoperation.

Results

A total of 2,840 patients were identified; 628 were brachial plexus operations. Overall complications were 4.4% and 7.0%, respectively. Median time for occurrence of any complication was 8 days. The most common complications were wound‐related (1.7%), which occurred at a median of 15 days postoperatively. Reoperation occurred in 1.8% of all cases; most commonly for musculoskeletal repair (16.7%). Unplanned readmissions occurred in 2.3% and were most often due to wound‐related problems (24.1%). Preoperatively contaminated wounds, inpatient procedures, and longer operative time seemed to have the most influence on all adverse events. In brachial plexus pathology, insulin‐dependent diabetes and emergency cases also negatively affected outcomes.

Conclusions

Complications usually occur one to two weeks postoperatively. Preoperatively contaminated wounds, inpatient procedures, and longer operative times influence outcome. Anatomical level of operation results in significantly different lengths of hospital stay; brachial plexus pathology has the longest length of stay.
Asymptotic behavior of the solution of singularly perturbed transmission problems in a periodic domain
Authors: Pukhtaievych Roman
Published: April 2018

This paper is devoted to the study of the asymptotic behavior of the solutions of singularly perturbed transmission problems in a periodically perforated domain. The domain is obtained by making in
a periodic set of holes, each of them of size proportional to a positive parameter ε. We first consider an ideal transmission problem and investigate the behavior of the solution as ε tends to 0. In particular, we deduce a representation formula in terms of real analytic maps of ε and of some additional parameters. Then we apply such result to a nonideal nonlinear transmission problem.
Blowup of solutions for the initial boundary value problem of the 3‐dimensional compressible damped Euler equations
Authors: Cheung Ka Luen
Published: April 2018

The blowup phenomenon of solutions is investigated for the initial boundary value problem of the 3‐dimensional compressible damped Euler equations. It is shown that if the initial functional associated with a general test function is large enough, the solutions of the damped Euler equations will blow up on finite time. Hence, a class of blowup conditions is established. Moreover, the blowup time could be estimated.
Numerical analysis of a water wave model with a nonlocal viscous dispersive term using the diffusive approach
Authors: Dumont S. , Manoubi I.
Published: April 2018

In this paper, we numerically study the water wave model with a nonlocal viscous term

urn:x-wiley:mma:media:mma4932:mma4932-math-0001
where
is the Riemann‐Liouville half‐order derivative in time. We propose and compare different numerical schemes based on the diffusive realizations of fractional operators.
Linearized stability and instability of nonconstant periodic solutions of Lagrangian equations
Authors: Zhang Meirong , Cen Xiuli , Cheng Xuhua
Published: April 2018

This paper is motivated by the stability problem of nonconstant periodic solutions of time‐periodic Lagrangian equations, like the swing and the elliptic Sitnikov problem. As a beginning step, we will study the linearized stability and instability of nonconstant periodic solutions that are bifurcated from those of autonomous Lagrangian equations. Applying the theory for Hill equations, we will establish a criterion for linearized stability. The criterion shows that the linearized stability depends on the temporal frequencies of the perturbed systems in a delicate way.
Higher spin generalisation of Fueter's theorem
Authors: Eelbode David , Janssens Tim
Published: April 2018

In this paper, we generalize Fueter's theorem to the higher spin setting. To do so, we consider an alternative proof for the celebrated theorem that uses the Fischer decomposition. This decomposition is then extended to spaces of polynomials that depend on wedge variables, after which we can finish the proof of our higher spin Fueter theorem.
Chlorogenic Acid Protects Against oxLDL‐Induced Oxidative Damage and Mitochondrial Dysfunction by Modulating SIRT1 in Endothelial Cells
Authors: Tsai Kun‐Ling , Hung Ching‐Hsia , Chan Shih‐Hung , Hsieh Pei‐Ling , Ou Hsiu‐Chung , Cheng Yung‐Hsin , Chu Pei‐Ming
Published: April 2018

Scope

Endothelial dysfunction is an important mechanism in the development of atherosclerosis and is thought to be critical for predicting cardiovascular diseases. Previous reports suggested that chlorogenic acid (CGA) is a potent antioxidant and anti‐inflammatory compound. The molecular mechanisms underlying the inhibitory effects of CGA on oxLDL‐induced oxidative injuries in human endothelial cells are still largely unknown. This study is aimed to test the hypothesis that CGA protects against oxLDL‐facilitated oxidative stress by upregulating SIRT1 and to explore the role of AMPK/PGC‐1 pathway and mitochondrial biogenesis.

Methods and results

HUVECs were treated with oxLDL in the presence or absence of CGA pretreatment. Our data indicated that CGA pretreatment increased SIRT1 deacetylase activity levels. In addition, CGA reversed oxLDL‐impaired SIRT1 and AMPK/PGC‐1 activity and mitigated oxLDL‐induced oxidative stress and dysfunction of mitochondrial biogenesis. However, silencing SIRT1, AMPK, and PGC‐1 abated the ability of CGA to protect against oxidative stress. Results from the present study also suggested that CGA inhibits oxLDL‐induced endothelial apoptosis through modulating SIRT1 and AMPK/PGC‐1 function.

Conclusion

These findings provide new insights into possible molecular mechanisms by which CGA mitigates oxLDL‐induced endothelial oxidative stress and mitochondrial dysfunction by activating SIRT1 and modulating the AMPK/PGC‐1 signaling pathway.
NMReDATA, a standard to report the NMR assignment and parameters of organic compounds
Authors: Pupier Marion , Nuzillard Jean‐Marc , Wist Julien , Schlörer Nils E. , Kuhn Stefan , Erdelyi Mate , Steinbeck Christoph , Williams Antony J. , Butts Craig , Claridge Tim D.W. , Mikhova Bozhana , Robien Wolfgang , Dashti Hesam , Eghbalnia Hamid R. , Farès Christophe , Adam Christian , Kessler Pavel , Moriaud Fabrice , Elyashberg Mikhail , Argyropoulos Dimitris , Pérez Manuel , Giraudeau Patrick , Gil Roberto R. , Trevorrow Paul , Jeannerat Damien
Published: April 2018

Even though NMR has found countless applications in the field of small molecule characterization, there is no standard file format available for the NMR data relevant to structure characterization of small molecules. A new format is therefore introduced to associate the NMR parameters extracted from 1D and 2D spectra of organic compounds to the proposed chemical structure. These NMR parameters, which we shall call NMReDATA (for nuclear magnetic resonance extracted data), include chemical shift values, signal integrals, intensities, multiplicities, scalar coupling constants, lists of 2D correlations, relaxation times, and diffusion rates. The file format is an extension of the existing Structure Data Format, which is compatible with the commonly used MOL format. The association of an NMReDATA file with the raw and spectral data from which it originates constitutes an NMR record. This format is easily readable by humans and computers and provides a simple and efficient way for disseminating results of structural chemistry investigations, allowing automatic verification of published results, and for assisting the constitution of highly needed open‐source structural databases.
Hemodynamic response function (HRF) variability confounds resting‐state fMRI functional connectivity
Authors: Rangaprakash D. , Wu Guo‐Rong , Marinazzo Daniele , Hu Xiaoping , Deshpande Gopikrishna
Published: April 2018

Purpose

fMRI is the convolution of the hemodynamic response function (HRF) and unmeasured neural activity. HRF variability (HRFv) across the brain could, in principle, alter functional connectivity (FC) estimates from resting‐state fMRI (rs‐fMRI). Given that HRFv is driven by both neural and non‐neural factors, it is problematic when it confounds FC. However, this aspect has remained largely unexplored even though FC studies have grown exponentially. We hypothesized that HRFv confounds FC estimates in the brain's default‐mode‐network.

Methods

We tested this hypothesis using both simulations (where the ground truth is known and modulated) as well as rs‐fMRI data obtained in a 7T MRI scanner (N = 47, healthy). FC was obtained using 2 pipelines: data with hemodynamic deconvolution (DC) to estimate the HRF and minimize HRFv, and data with no deconvolution (NDC, HRFv‐ignored). DC and NDC FC networks were compared, along with regional HRF differences, revealing potential false connectivities that resulted from HRFv.

Results

We found evidence supporting our hypothesis using both simulations and experimental data. With simulations, we found that HRFv could cause a change of up to 50% in FC. With rs‐fMRI, several potential false connectivities attributable to HRFv, with majority connections being between different lobes, were identified. We found a double exponential relationship between the magnitude of HRFv and its impact on FC, with a mean/median error of 30.5/11.5% caused in FC by HRF confounds.

Conclusion

HRFv, if ignored, could cause identification of false FC. FC findings from HRFv‐ignored data should be interpreted cautiously. We suggest deconvolution to minimize HRFv.
Toward in vivo quantification of induced RF currents on long thin conductors
Authors: Griffin Gregory H. , Ramanan Venkat , Barry Jennifer , Wright Graham A.
Published: April 2018

Purpose

Most MR‐guided catheter‐based procedures, and imaging of patients with implanted medical devices, are currently contraindicated due to a significant risk of heating associated with induced RF currents. The induced RF current produces a corresponding artifact which can be used to remotely characterize current and safely predict RF heating. Application of this remote technique in vivo to safely quantify RF heating risk may allow for execution of many scans currently contraindicated. Sources of phase other than induced RF current may present difficulty in practical in vivo.

Methods

A custom ultra‐short echo time (UTE) sequence was developed to minimize unwanted phase contributions. A phantom experiment was performed to compare current characterization using a stock gradient‐echo (GRE) sequence and the custom UTE sequence following calibration of the temperature measurement apparatus using a previously published heating prediction technique. Animal experiments were used to investigate the feasibility of using the UTE sequence to quantify RF heating.

Results

Current characterization and heating prediction with a stock GRE sequence was equivalent to that with the custom UTE sequence. Heating measurements and image‐based predictions in animal experiments agreed within error in all experiments.

Conclusion

Through comparison of measured heating and image‐based prediction, feasibility of using a custom UTE sequence to quantify RF heating risk in vivo was demonstrated.
Hybrid T2‐ and T1‐weighted radial acquisition for free‐breathing abdominal examination
Authors: Benkert Thomas , Mugler John P. , Rigie David S. , Sodickson Daniel K. , Chandarana Hersh , Block Kai Tobias
Published: April 2018

Purpose

Most clinical MR examinations require acquisition of different image contrasts. For abdominal exams, the scans are conventionally performed as separate acquisitions using respiratory gating or repeated breath holding, which can be time‐inefficient and challenging for patients. Here, a hybrid imaging approach is described that creates T2‐ and T1‐weighted images from a single scan and allows for free‐breathing acquisition.

Theory and Methods

T2‐weighted data is collected using 3D fast spin‐echo (FSE) acquisition with motion‐robust radial stack‐of‐stars sampling. The wait time between the FSE trains is used to acquire T1‐weighted gradient‐echo (GRE) data. Improved robustness is achieved by extracting a respiratory signal from the GRE data and using it for motion‐weighted reconstruction.

Results

As validated in simulations and phantom scans, GRE acquisition in the wait time has minor effect on the signal strength and contrast. Volunteer scans at 1.5T showed that T2‐ and T1‐weighted hybrid imaging is feasible during free‐breathing. Furthermore, it has been demonstrated in a patient that hybrid imaging with T1‐weighted Dixon acquisition is possible.

Conclusion

The described hybrid sequence enables comprehensive T2‐ and T1‐weighted imaging in a single scan. In addition to free‐breathing abdominal examination, it promises value for clinical applications that are frequently affected by motion artifacts.
The robustness of T2 value as a trabecular structural index at multiple spatial resolutions of 7 Tesla MRI
Authors: Lee D.K. , Song Y.K. , Park B.W. , Cho H.P. , Yeom J.S. , Cho G. , Cho H.
Published: April 2018

Purpose

To evaluate the robustness of MR transverse relaxation times of trabecular bone from spin‐echo and gradient‐echo acquisitions at multiple spatial resolutions of 7 T.

Methods

The effects of MRI resolutions to T2 and
of trabecular bone were numerically evaluated by Monte Carlo simulations. T2,
, and trabecular structural indices from multislice multi‐echo and UTE acquisitions were measured in defatted human distal femoral condyles on a 7 T scanner. Reference structural indices were extracted from high‐resolution microcomputed tomography images. For bovine knee trabecular samples with intact bone marrow, T2 and
were measured by degrading spatial resolutions on a 7 T system.

Results

In the defatted trabecular experiment, both T2 and
values showed strong (
 > 0.80) correlations with trabecular spacing and number, at a high spatial resolution of 125 µm3. The correlations for MR image‐segmentation‐derived structural indices were significantly degraded (
 < 0.50) at spatial resolutions of 250 and 500 µm3. The correlations for
rapidly dropped (
 < 0.50) at a spatial resolution of 500 µm3, whereas those for T2 remained consistently high (
 > 0.85). In the bovine trabecular experiments with intact marrow, low‐resolution (approximately 1 mm3, 2 minutes) T2 values did not shorten (
 > 0.95 with respect to approximately 0.4 mm3, 11 minutes) and maintained consistent correlations (
 > 0.70) with respect to trabecular spacing (turbo spin echo, 22.5 minutes).

Conclusion

T2 measurements of trabeculae at 7 T are robust with degrading spatial resolution and may be preferable in assessing trabecular spacing index with reduced scan time, when high‐resolution 3D micro‐MRI is difficult to obtain.
Robust motion correction in CEST imaging exploiting low‐rank approximation of the z‐spectrum
Authors: Wech Tobias , Köstler Herbert
Published: April 2018

Purpose

To introduce and evaluate an image registration technique for robust quantification of CEST acquisitions corrupted by motion.

Methods

The proposed iterative algorithm exploits a low‐rank approximation of the z‐spectrum (LRAZ), to gradually separate the contrast variation due to saturation at different off‐resonance frequencies and accompanying motion. This registration method was first tested in a creatine CEST analysis of a phantom with simulated rigid motion. Subsequently, creatine CEST acquisitions in the human thigh during exercise were exemplarily corrected.

Results

The z‐spectrum obtained by applying LRAZ to the corrupted phantom series exhibited a normalized RMS error with respect to the noncorrupted gold standard series of less than 4%. The corresponding creatine map resulting from an asymmetry analysis of the registered data showed only little difference with regard to the noncorrupted determination, too. A comparable performance was observed exploiting LRAZ for the correction of nonrigid motion within the dynamic CEST acquisitions in skeletal muscles. While for the phantom simulations, high‐quality registration was also possible by using a single reference image for the whole series and mutual information as similarity metric, this conventional approach resulted in inappropriate correction of the more complicated motion of the human thigh.

Conclusion

The newly introduced method allows for a robust registration of CEST image series, which are corrupted by rigid and nonrigid motion of the investigated organ. The technique therefore improves the diagnostic value in various applications of CEST.
In‐plane “superresolution” MRI with phaseless sub‐pixel encoding
Authors: Hennel Franciszek , Tian Rui , Engel Maria , Pruessmann Klaas P.
Published: April 2018

Purpose

Acquisition of high‐resolution imaging data using multiple excitations without the sensitivity to fluctuations of the transverse magnetization phase, which is a major problem of multi‐shot MRI.

Theory and Methods

The concept of superresolution MRI based on microscopic tagging is analyzed using an analogy with the optical method of structured illumination. Sinusoidal tagging is shown to provide subpixel resolution by mixing of neighboring spatial frequency (k‐space) bands. It represents a phaseless modulation added on top of the standard Fourier encoding, which allows the phase fluctuations to be discarded at an intermediate reconstruction step. Improvements are proposed to correct for tag distortions due to magnetic field inhomogeneity and to avoid the propagation of Gibbs ringing from intermediate low‐resolution images to the final image. The method was applied to diffusion‐weighted EPI.

Results

Artifact‐free superresolution images can be obtained despite a finite duration of the tagging sequence and related pattern distortions by a field map based phase correction of band‐wise reconstructed images. The ringing effect present in the intermediate images can be suppressed by partial overlapping of the mixed k‐space bands in combination with an adapted filter. High‐resolution diffusion‐weighted images of the human head were obtained with a three‐shot EPI sequence despite motion‐related phase fluctuations between the shots.

Conclusion

Due to its phaseless character, tagging‐based sub‐pixel encoding is an alternative to k‐space segmenting in the presence of unknown phase fluctuations, in particular those due to motion under strong diffusion gradients. Proposed improvements render the method practicable in realistic conditions.
Investigating the motives of patients with knee OA undergoing a TKR: A qualitative interview study
Authors: Traumer Line , Sørensen Erik Elgaard , Kusk Kathrine Hoffmann , Skou Søren Thorgaard
Published: April 2018

Objective

Total knee replacement (TKR) is generally considered effective as treatment of pain and functional limitations in end‐stage knee osteoarthritis (OA). However, many patients delay surgery for months or are unwilling to undergo TKR despite pain and functional limitations. Hence, a qualitatively assessment of what actually affects the patient's decision to undergo TKR would be important. Therefore, the purpose of this study was to investigate the motives of patients with knee OA choosing to undergo TKR and to explore the factors considered important during their decision‐making process.

Methods

Eleven patients undergoing TKR were recruited from the outpatient orthopedic department. Using an interview guide, in‐depth semi‐structured interviews were conducted at participants' home. All interviews were recorded, transcribed and a thematic analysis was performed.

Results

The analysis revealed that the interaction between doctor and patient emerged as a factor highly influential on patients' decision‐making process with patients choosing the treatment option suggested by the doctor. Using x‐rays, revealing no cartilage between the bones, as a reason for choosing to undergo TKR was a legitimate argument among patients. The prospect of avoiding taking high doses of pain‐relieving medication and hearing positive experiences of others who had undergone TKR motivated patients to undergo TKR. However, negative experiences of others were neglected.

Conclusions

Patients' decision‐making process was influenced by several factors, with some factors being more influential than others. Knowledge of which factors patients consider important in relation to their decision to undergo TKR can facilitate and support shared decision‐making regarding TKR.
The impact of social capital on clinical risk management in nursing: a survey in Iranian public educational hospitals
Authors: Jafari Mehdi , Pourtaleb Arefeh , Khodayari‐Zarnaq Rahim
Published: April 2018

Aim

This study aimed to explore the social capital impact on clinical risk management from nurses’ viewpoints.

Design

This was a cross‐sectional and analytical study conduct in six public educational hospitals affiliated to Tehran University of Medical Sciences (TUMS).

Method

Questionnaires were used as the data collection tool. Data were analysed using descriptive statistics, parametric and non‐parametric tests by SPSS 16 at a significance level of 0.05.

Results

Risk management, social capital and all its three dimensions evaluated in moderate level. It is confirmed that the social capital is one of the factors associated with the improvement of clinical risk management. There was a significant relationship between clinical risk management and social capital. In this respect, hospital managers and decision‐makers could enhance clinical risk management by identifying and increasing different dimensions of social capital which consequently led to have a better patient safety culture in hospitals.
Development of an adjustment ability scale for outpatients with cancer: Verification of its reliability and validity
Authors: Hirokawa Keiko , Suzuki Shizue
Published: April 2018

Aims

To develop an adjustment ability scale for outpatients with cancer and to investigate its reliability and validity.

Design

Quantitative study.

Methods

A proposed adjustment ability scale was prepared based on scale development guidelines. Its reliability and validity were statistically analysed using data obtained from 369 patients.

Results

Six factors were extracted from the factor analysis. Cronbach's α coefficient was 0.95 and the test–retest reliability coefficient was 0.83. A correlation coefficient of .48 was determined between the adjustment ability scale and the Mental Adjustment to Cancer scale (Japanese version), which assesses psychological adaptations via the cognitive‐behavioural responses of patients with cancer. The correlation coefficient between the scale and the Functional Assessment of Cancer Therapy‐General (Japanese version 4), which measures quality of life among patients with cancer, was 0.15.
Pathways of Association from Stress to Obesity in Early Childhood
Authors: Miller Alison L. , Lumeng Julie C.
Published: April 2018

Objective

The objective of this study is to critically review the literature on early life stress in relation to obesity in humans, including the multiple biological and behavioral mechanisms through which early life stress exposure (birth to the age of 5 years) may associate with obesity risk during childhood.

Methods

A review of the literature was conducted to identify studies on associations between early childhood stress and risk for obesity and the mechanisms of association. Multiple databases (PubMed, PsycInfo, Google Scholar) were used in the search as well as a "snowball" search strategy. All study designs were included.

Results

Early life stress and adverse childhood experiences are associated with obesity and overweight in adults. Evidence is less consistent in children. Studies vary in the nature of the stress examined (e.g., chronic vs. acute), sample characteristics, and study designs. Longitudinal studies are needed, as the effects of early life stress exposure may not emerge until later in the life‐span. Early life stress exposure is associated with biological and behavioral pathways that may increase risk for childhood obesity.

Conclusions

There is evidence that early life stress is associated with multiple biological and behavioral pathways in children that may increase risk for later obesity. Little work has detailed the interconnections among these mechanisms across development or identified potential moderators of the association. Mapping the mechanisms connecting early life stress exposure to obesity risk in young children longitudinally should be a priority for obesity researchers. Recommendations for developmentally sensitive approaches to research that can inform obesity prevention strategies are presented.
Daily Snacking Occasions and Weight Status Among US Children Aged 1 to 5 Years
Authors: Kachurak Alexandria , Davey Adam , Bailey Regan L. , Fisher Jennifer O.
Published: April 2018

Objective

To characterize associations of snacking frequency with weight status among US children aged 1 to 5 years.

Methods

Participants were children (n = 4,669) aged 1 to 5 years in the 2005 to 2014 National Health and Nutrition Examination Survey (NHANES). Snacking was assessed by two 24‐hour dietary recalls using definitions that considered “snack” occasions as well as other foods/beverages consumed between meals. Overweight/obesity (OW/OB) was defined using percentile cutoffs: ≥ 97.7th weight‐for‐length (< 2 years) cutoff and the ≥ 85th BMI‐for‐age (≥ 2 years) cutoff. Linear/logistic regressions evaluated snacking based on daily occasions and relative to current recommendations (two to three snacks per day).

Results

During 2005 to 2014, US children aged 1 to 5 years consumed, on average, two to three snacks daily. Children with normal weight in both age groups tended to snack less frequently than children with OW/OB when considering all foods/beverages eaten between meals (P < 0.01‐0.12). Across most snacking definitions, children < 2 years who snacked more frequently than recommended had greater odds of having OW/OB (P < 0.01‐0.12) and consumed greater daily snack energy than those who snacked within recommendations (all P < 0.01). Recommendations did not clearly delineate weight status among children aged 2 to 5 years.

Conclusions

Snacking frequency and weight are positively associated among US children 1 to 5 years old, with most consistent associations seen among children < 2 years old and when considering all foods/beverages consumed between meals.
Hierarchical SAPO‐34 Architectures with Tailored Acid Sites using Sustainable Sugar Templates
Authors: Miletto Ivana , Ivaldi Chiara , Paul Geo , Chapman Stephanie , Marchese Leonardo , Raja Robert , Gianotti Enrica
Published: April 2018

In a distinct, bottom‐up synthetic methodology, monosaccharides (fructose and glucose) and disaccharides (sucrose) have been used as mesoporogens to template hierarchical SAPO‐34 catalysts. Detailed materials characterization, which includes solid‐state magic angle spinning NMR and probe‐based FTIR, reveals that, although the mesopore dimensions are modified by the identity of the sugar template, the desirable acid characteristics of the microporous framework are retained. When the activity of the hierarchical SAPO‐34 catalysts was evaluated in the industrially relevant Beckmann rearrangement, under liquid‐phase conditions, the enhanced mass‐transport properties of sucrose‐templated hierarchical SAPO‐34 were found to deliver a superior yield of ϵ‐caprolactam.
Rigid amorphous phase and constrained polymer chains in poly(L‐lactide) nanocomposites with carboxylated carbon nanotubes prepared via reactive melt mixing
Authors: Yousefzade Omid , Garmabi Hamid , Puiggali Jordi , Heydarnejad Moghadam Mohammad
Published: April 2018

Evaluation of constrained polymer chains and the glass transition behavior of the nanocomposite constituted by poly(L‐lactide) (PLLA) and functionalized carbon nanotubes (f‐CNTs) have been carried out. To control thermal degradation, nanocomposites were prepared via reactive melt mixing taking advantage of the capacity of carboxylic groups of both PLLA and f‐CNTs to participate in chain extension reactions. At low f‐CNT content (e.g., 0.2 and 0.5 wt%), a good dispersion of f‐CNTs was observed due to scarce bonds established between both components (i.e., the polymer matrix and the nanofiller), whereas at higher f‐CNT content (e.g., 1 wt%), a greater number of epoxy groups of the chain extender were bonded to carboxyl groups of f‐CNTs, giving rise to a highly significant crosslinking of CNT and a lower molecular weight of PLLA. Crystallinity, glass transition temperature and both the rigid polymer chains and constrained polymer chains were influenced by the dispersion state of f‐CNTs after reactive melt mixing and the thermal history (e.g., cooling rate form the melt) of samples. For evaluation of interphases between poly(lactic acid) and f‐CNTs, a simple method was developed for the considered tube‐like nanoparticles. Specifically, thicknesses of the generated interphases were calculated from DMA experiments. POLYM. COMPOS., 39:E1280–E1293, 2018. © 2018 Society of Plastics Engineers
Dynamic mechanical properties of sugar palm/glass fiber reinforced thermoplastic polyurethane hybrid composites
Authors: Atiqah A. , Jawaid M. , Sapuan S. M. , Ishak M. R.
Published: April 2018

Hybrid composites based on thermoplastic polyurethane were fabricated with the addition of sugar palm fiber and glass fiber. The best ratio of 30 wt% sugar palm fiber to 10 wt% glass fiber was used to reinforce the hybrid composites, which were then subjected to dynamic mechanical analysis (DMA) to determine their dynamic properties. Three types of fiber treatment were assessed as follows: 6% alkaline (TNSP), 2% silane (TSSP) and combined 6% alkaline‐ 2% silane (TNSSP) for 3 h. The untreated and treated hybrid composites were fabricated by the melt‐compounding method, followed by a hot pressing moulding. The DMA properties, including storage modulus, loss modulus and damping factor, were measured by a Dynamic Mechanical Analyzer. The hybrid composites of TNSSP showed highest storage modulus, loss modulus as compared to other treated hybrid composites. The peak height of damping factor was low for TNSSP and highest for TSSP hybrid composites. The Cole–Cole analysis was carried out to investigate the phase behavior of the untreated and treated hybrid composites. The study demonstrated that the combined 6% alkaline‐2% silane fiber treatment was the most effective in enhancing the dynamic mechanical properties of the SPF/GF reinforced TPU hybrid composites. It is clear that, the treated fibers influenced the DMA of thermoplastic polyurethane hybrid composites. The overall result showed that treated sugar pam/glass reinforced thermoplastic polyurethane improved the dynamic mechanical analysis for hybrid composites suitable for automotive parts. POLYM. COMPOS., 40:1329–1334, 2019. © 2018 Society of Plastics Engineers
Exploiting poly(ɛ‐caprolactone) and cellulose nanofibrils modified with latex nanoparticles for the development of biodegradable nanocomposites
Authors: Vilela Carla , Engström Joakim , Valente Bruno F. A. , Jawerth Marcus , Carlmark Anna , Freire Carmen S. R.
Published: April 2018

This study reports the development of nanocomposites based on poly(ɛ‐caprolactone) (PCL) and cellulose nanofibrils (CNF) modified with cationic latex nanoparticles. The physical adsorption of these water‐based latexes on the surface of CNF was studied as an environment‐friendly strategy to enhance the compatibility of CNF with a hydrophobic polymeric matrix. The latexes are composed of amphiphilic block copolymers based on cationic poly(N,N‐dimethylaminoethyl methacrylate‐co‐methacrylic acid) as the hydrophilic block, and either poly(methyl methacrylate) or poly(n‐butyl methacrylate) as the hydrophobic block. The simple and practical melt‐mixing of PCL‐ and latex‐modified CNF yielded white homogeneous nanocomposites with complete embedment of the nanofibrils in the thermoplastic matrix. All nanocomposites are semicrystalline materials with good mechanical properties (Young's modulus = 43.6–52.3 MPa) and thermal stability up to 335–340°C. Degradation tests clearly showed that the nanocomposites slowly degrade in the presence of lipase‐type enzyme. These PCL/CNF‐latex nanocomposite materials show great promise as future environmentally friendly packaging materials. POLYM. COMPOS., 40:1342–1353, 2019. © 2018 Society of Plastics Engineers
Study and evaluation of dispersion of polyhedral oligomeric silsesquioxane and silica filler in polypropylene composites
Authors: Niemczyk Arkadiusz , Dziubek Katarzyna , Czaja Krystyna , Frączek Daniel , Piasecki Ryszard , Rabiej Stanisław , Dutkiewicz Michał
Published: April 2018

Various methods were used for evaluation of homogeneity of polypropylene (PP) matrix composites with octakis([n‐octyl]dimethylsiloxy)octasilsesquioxane, octakis([n‐octadecyl]dimethylsiloxy)octasilsesquioxane, and silica (SiO2) fillers. The filler dispersion was determined on the basis of the results from the wide‐angle X‐ray scattering (WAXS) analysis, from the tests of selected mechanical properties, from scanning electron microscopy (SEM) with energy dispersive X‐ray spectroscopy and from the decomposable entropic descriptor method. The use of different methods allowed to evaluate homogeneity of PP composites on various levels and with different precisions. The dispersion degree was found to be mostly depended on the kind and amount of the filler used. The presence of long n‐alkyl chain substituents in POSS molecules greatly improved the level of filler dispersion in the polymer matrix in comparison to silica which was visually assessed by SEM. The WAXS method revealed the formation of filler aggregates in the PP matrix which influenced the structural characteristic of PP composites and changed the mechanical properties of those materials. However, the decomposable entropic descriptor method provided the possibility of quantitative and the most objective estimation of homogeneity of the obtained composite materials. POLYM. COMPOS., 40:1354–1364, 2019. © 2018 Society of Plastics Engineers
A new strategy for the preparation of silver/epoxy/poly(vinylidene fluoride) dielectric composites with a multi‐interface structure for suppressed dielectric loss
Authors: Zhang Jingjing , Li Hairong , Hu Die , Fang Dong , Luo Zhiping , Tu Junyang , Huang Jing , Jiang Ming , Xiong Chuanxi
Published: April 2018

Dielectric materials with low dielectric loss are highly desirable for future energy storage and management. Relatively high dielectric loss and complex fabrication process with high cost are current major factors limiting percolative dielectric composites for applications. In this study, low dielectric loss has been obtained using multi‐interface silver/epoxy/poly(vinylidene fluoride) (Ag/epoxy/PVDF) percolative composites by simple thermal curing and mechanical crushing, coupled with melt mixing and hot pressing. Isolated Ag/epoxy islands were formed in the PVDF matrix. The dielectric permittivity of the composite near the percolation threshold reached 132 whereas the loss tangent was around 0.1 at 100 Hz. This multi‐interface structure played an important role in suppressing the dielectric loss and achieving the relatively high dielectric permittivity in these composites. Our results suggest that the simple and low‐cost fabrication of the Ag/epoxy/PVDF is a promising approach for the development of low‐loss percolative dielectric composites. POLYM. COMPOS., 39:E2606–E2610, 2018. © 2018 Society of Plastics Engineers
Comparison between polyethylene glycol and tributyl citrate to modify the properties of wood fiber/polylactic acid biocomposites
Authors: Yang Zhaozhe , Bi Hongjie , Bi Yongbao , Rodrigue Denis , Xu Min , Feng Xinhao
Published: April 2018

In this work, polyethylene glycol (PEG) and tributyl citrate (TBC) are proposed to modify the properties of wood fiber (WF, 20 wt%)‐reinforced polylactide (PLA, 80 wt%) biocomposites. The reinforcing and toughening effects of these additives were systematically investigated by comparing their mechanical, thermal and rheological properties. It was found that 5 wt% TBC improved the compatibility between WF and PLA and resulted in increased tensile strength (15%) and thermal stability (4%) of the biocomposites compared with those of unmodified biocomposites. The glass transition temperature, melting temperature, and crystallinity of TBC‐modified biocomposites were lower than those of PEG biocomposites. In addition, the storage modulus, loss modulus and complex viscosity of TBC‐modified biocomposites were effectively improved at low TBC content (5–10 wt%), whereas reduced properties were obtained when the same PEG content was added. As wettability is always a problem in biocomposites, the contact angle was not changed with TBC content (up to 20 wt%), and a linear decrease was observed with a PEG content up to 30 wt%. POLYM. COMPOS., 40:1384–1394, 2019. © 2018 Society of Plastics Engineers
Ectopic expression of the PISTILLATA homologous MdPI inhibits fruit tissue growth and changes fruit shape in apple
Authors: Yao Jia‐Long , Xu Juan , Tomes Sumathi , Cui Wei , Luo Zhiwei , Deng Cecilia , Ireland Hilary S. , Schaffer Robert J. , Gleave Andrew P.
Published: April 2018

Fruit shape represents a key trait that consumers use to identify and select preferred cultivars, and although the manipulation of this trait is an opportunity to create novel, differentiated products, the molecular mechanisms regulating fruit shape are poorly understood in tree fruits. In this study, we have shown that ectopic expression of Malus domestica PISTILLATA (MdPI), the apple ortholog of the floral organ identity gene PISTILLATA (PI), regulates apple fruit tissue growth and shape. MdPI is a single‐copy gene, and its expression is high during flower development but barely detectable soon after pollination. Transgenic apple plants with ectopic expression of MdPI produced flowers with white sepals and a conversion of sepals to petals. Interestingly, these plants produced distinctly flattened fruit as a consequence of reduced cell growth at the basipetal position of the fruit. These altered sepal and fruit phenotypes have not been observed in studies using Arabidopsis. This study using apple has advanced our understanding of PI functions outside the control of petal and stamen identity and provided molecular genetic information useful for manipulating fruit tissue growth and fruit shape.