bluuebunny/crossref_metadata_2025_split huggingface dataset:
Treatment Options for Multinucleate Cell Angiohistiocytoma: A Case Series and Review of the Literature
Authors: Taibo Ana , Padin Cristina Prego , Losada Jesus Del Pozo , Fonseca Eduardo 
Published: March 2023

Background Multinucleate cell angiohistiocytoma (MCAH) is an unusual fibrohistiocytic proliferation in the dermis with vascular hyperplasia. Numerous clinicopathological studies of MCAH have been published, but little has been written in relation to treatment. Objectives The aim of the present study is to review the therapeutical approaches for MCAH in the literature and to report the results of the different therapies followed at our institution. Methods A literature review was conducted including all MCAH published cases that followed any therapy. Search terms included “multinucleate cell angiohistiocytoma” or “MCAH” and “treatment” or “therapy”. Also, all cases of MCAH treated at our institution from 2010 to 2020 are reported. Results The literature search revealed 16 cases of MCAH treated with any of the therapeutic options. At our institution, 9 patients have been treated of MCAH between 2010 and 2020. Over 75% of them were female, and the median age was 56 years (range 47-73). More than 50% had lesions on the dorsum of the hands. Surgical excision was indicated in 2 patients, ablative CO2 laser was used in 1 patient and the 6 remaining ones followed vascular-targeted therapies (PDL and IPL). A satisfactory cosmetic result was achieved in all of them. Conclusions We propose PDL therapy as a first-line treatment for MCAH since it achieves satisfactory esthetic results, while being well-tolerated. Selecting those amenable patients according to morphologic characteristics may be useful to avoid unsuccessful therapies. In MCAH with predominant fibrous stroma, surgery or CO2 laser may be the best option.
Factors influencing the mental health of autistic children and teenagers: Parents’ observations and experiences
Authors: Mukherjee Suzanne , Beresford Bryony 
Published: March 2023

The high prevalence of mental health and behaviour problems among autistic children and adults is an issue of concern to the autism community. Many studies have been undertaken to identify the factors that protect against/or increase the risk of such difficulties. However, this research is dominated by quantitative observational studies. In this study, we sought to investigate the same issue using a qualitative research approach, positioning parents as experts and eliciting their theories as to what influenced their child’s mental health from diagnosis to the late teenage years. In-depth interviews were undertaken with 33 parents (30 mothers, 3 fathers) of 31 autistic teenagers (21 males, 10 females) aged between 15 and 19 years (median 17 years) purposively sampled from an existing cohort (QUEST). Parents believed a wide range of child-centred, developmental and socio-environmental factors had played a role in their child’s mental health, alongside life events involving loss and separation. A number of these factors have received little or no research attention to date (e.g. aspects of the school environment). The findings have important implications, highlighting factors that should be given priority in future research, as well as interventions needed to support the mental health of autistic teenagers. Lay abstract Autistic people are more likely to experience mental health difficulties compared to neurotypical people. It is very important that we understand what increases the risk for mental health difficulties, and what helps to protect against them. So far, research on this for children and young people has only investigated a small number of factors and these have been chosen by researchers and clinicians. This study took a different approach in which parents’ expertise in their children was recognised. Parents were asked to tell the story of their autistic teenagers’ mental health from diagnosis in early childhood through to the present, and to explain the ‘theories’ they developed about what affected their child’s mental health – positively and negatively – and how. Parents believed a wide range of factors played a role. These include: (1) aspects of their child (e.g. their autistic traits, intelligence); (2) aspects of their surroundings (e.g. the efforts parents make to prevent and respond to their child’s difficulties, features of the school they attend, availability of social activities); (3) changes their child experienced growing up (e.g. puberty, awareness of being autistic); and (4) life events involving loss and separation. Many of the factors parents identified as important have received little or no research attention to date. The findings suggest issues that should be considered in future research and reveal ways that support for parents and autistic children and teenagers can be improved.
Bisphenol-A release from thermoplastic clear aligner materials: A systematic review
Authors: Peter Elbe , J Monisha , George Suja Ani 
Published: March 2023

Aim: The aim of the present study was to undertake a systematic review of the available evidence on the release of bisphenol-A (BPA) from thermoplastic materials used in the fabrication of clear aligners (CA). Methods: Electronic databases, such as MEDLINE (via PubMed), Google Scholar, Scopus, Cochrane Library, Web of Science, OpenGrey, and the U.S. National Institute of Heath-Clinical Trials, were searched up to 27 October 2022. In vivo/in vitro studies that assessed the release of BPA from different thermoplastic CA materials, with or without a control group, were selected. The risk of bias (RoB) in the randomised controlled trials (RCT) and in vitro studies was assessed using the Cochrane RoB tool and the guidelines for the reporting of pre-clinical studies, respectively. The quality of evidence was determined using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) Pro tool. Results: Six studies were considered for review from a total of 1926 records. This included one RCT and five in vitro studies. Only two studies found leaching of BPA, while four did not report any traces. The RoB was found to be moderate to high. The GRADE evidence level ranged from low to very low. Five of the included studies were conducted in vitro. Significant heterogeneity among the included studies prevented a quantitative synthesis. Conclusion: In light of the available conflicting evidence, BPA release from CAs can neither be confirmed nor denied. Safety remains questionable until high-quality in vivo trials prove otherwise. Registration: PROSPERO CRD42022310434.
The Use of Chemical Coupling Agents in Glass Reinforced Polyolefins
Authors: Cameron R. , Constable R.C. 
Published: March 2023

European demand for glass filled reinforced polyolefins continues to show significant growth rates. The main drive behind this is material replacement within the automotive and household appliance markets. In particular the automotive industry is turning towards glass filled polypropylene components both to reduce weight and increase recyclability. One route by which the performance of glass filled composites can be improved is by incorporating chemical coupling agents. In this paper the property enhancement achievable with POLYBOND 3002, supplied by BP Chemicals, is described. In addition development work with glass filled polymer alloys is presented.
Microstructure of Composite Materials Using Small-Angle Neutron Scattering and Contrast Variation: Approaches toward Understanding the Structure of Carbon Black-Elastomer Mixtures
Authors: Hjelm Rex P. , Seeger Philip A. , Wampler Wesley A. 
Published: March 2023

Mixed composites of rubber and carbon black are of fundamental importance to rubber technology, and neutron scattering provides a unique view of structure in these interesting and complex systems. This is due, in part, to the nature of the interaction of the neutron with nuclei, which is a function of the specific nucleus, not on atomic number, per se. This allows neutrons to be used to probe fluctuations in chemical and isotopic composition and density in a manner that is a distinct from x-rays or electrons. This aspect of neutron scattering has been used extensively in the study of multicomponent systems, even when components have elements of similar atomic numbers. The large difference in scattering from some isotopes—hydrogen and deuterium being the most important example—can be used to enhance fluctuations in these systems and thus to probe structures that are not accessible by other methods. We describe the use of small-angle neutron scattering in carbon black, elastomer and carbon black elastomer mixtures using the method of contrast variation. In this approach the sample is suspended in solvents containing different proportions of perdeuterated and protonated molecules. The variation in scattering observed as a function of solvent scattering power gives information on the distribution of components within the sample. Our first experiences using this approach show the potentials of the technique. The use of solvents near the average scattering length density of the carbon black allows observation of non-uniformity in carbon black particles that has not been previously noted. Further, we have established that the shape of the scattering curves in N762 carbon black can be explained as scattering from spherical particles of size and polydispersity measured by electron microscopy. In N121, in which the particle sizes are smaller than N762, contribution to the scatter from the carbon black particle interactions is observable. In gels of solvent extracted carbon black and elastomer we find that the scattering is dominated by carbon black density fluctuations. We find further that the elastomer coats the carbon black particles, at least in N762. There are differences in the association of the carbon blacks in solvent extracted mixtures compared to the carbon blacks suspended in cyclohexane. There may be changes, as well, in the elastomer conformation in the mixtures compared to the polymer alone in cyclohexane. These differences are small in gels containing low concentrations of polyisoprene and carbon black, but are quite profound in a gel containing styrene butadiene rubber with high concentrations of components. Further measurements and modelling of die data will be needed to come to a more satisfactory picture of carbon black morphology and elastomer conformation in the solvent extracted mixtures.
Amorphous and Semi-Crystalline Nylon-6: Processing and Properties
Authors: Avramova Nadka 
Published: March 2023

The influence of processing conditions on the structure and properties of nylon-6 are investigated. Amorphous nylon-6 is obtained and its properties are compared with those of semi-crystalline nylon-6. The kinetics of crystallization of nylon-6 depends strongly on the previous thermal prehistory of the melt. The recently observed cumulative character in the structural memory of nylon-6 is successfully applied for obtaining this polymer in a pure amorphous state. It was demonstrated that a critical temperature exists above which the “memory” of this polymer can be erased, and this critical temperature is close to the equilibrium melting temperature T m°. The value of T m ° ≍280°C was evaluated using an independent technique. Melt annealing above this temperature suppresses the crystallization process due to destruction of all crystal nuclei. Amorphous nylon-6 was obtained by ultraquenching of its melt, previously treated at a temperature above T m °, to a temperature well below the glass transition region. The ultraquenched nylon-6 is characterized by amorphous initial structure and improved mechanical properties. The thermal behaviour, crystallization and mechanical properties are investigated by differential scanning calorimetry (DSC), wide angle X ray scattering (WAXS) and mechanical testing. After drawing and annealing, the tensile strength and elasticity modulus of initially amorphous nylon-6 increase three times and the elongation at break decreases by half as compared with conventionally quenched samples. The thermal treatment in vacuum of semi-crystalline nylon-6 affects both the structure and the molecular weight. It is demonstrated that the most important factor for the improvement of mechanical properties is the orientation in the amorphous regions. The lower die initial degree of crystallinity, the better are the orientation and the mechanical properties of nylon-6. The best mechanical properties of initially amorphous nylon-6 are explained by achievement of better orientation of molecules in the amorphous regions.
The Effect of Mixer Type and Processing Conditions on the Morphology of Polyamide/Polypropylene Blend
Authors: Vainio Tommi P. , Seppälä Jukka V. 
Published: March 2023

The effect of mixer type and processing conditions on the morphology of immiscible binary polyamide/polypropylene blend was studied. Blends were prepared in seven different mixers operating at various screw speeds. Changing the screw speed altered the shear stress and mixing intensity applied to the melt, and also the viscosity ratio. Average panicle sizes of the dispersed phase (PP) and the particle size distributions were determined for extruded and for subsequently injection moulded blends. The number average particle size level achieved in the melt blending was fairly well transferred to the injection moulded blend although the size distribution was broadened after the injection moulding due to the formation of both small (≍1 μm) and large (>10 μm) particles. The morphology of the skin region was very different from that of the core region in both the extruded and the injection moulded blends. The dispersed phase droplet size was dependent on screw speed to some degree. This dependency was greatest for the single screw extruder. Particle size correlated strongly with shear stress, specific mechanical energy input, and mixing intensity of the mixer. Shear stress, we were led to conclude, is a more important factor in controlling the morphology than the shear-rate-dependent viscosity ratio. Mechanical properties of the blends were poor due to weak adhesion at the interface of the blend components. Additionally, we found that melt blending promoted a better and more homogeneous dispersion in the injection moulded blend.
Moisture Absorption and its Influence on the Tensile Properties of Glass-Fibre Reinforced Polyamide 6,6
Authors: Akay M. 
Published: March 2023

The equilibrium amounts of moisture absorbed by a range of grades of glass fibre reinforced polyamide 6,6 were approximately proportional to the weight fraction of the polymer. However, the moisture diffusivity was found to be also a function of variations in specimen preparation and microstructure. The diffusivities of the moulded composite specimens indicated a law of mixtures relationship; whereas those with machined edges differed significantly. Moisture-induced deterioration of tensile strength was most severe up to 1.5% and 3% by weight moisture contents for the glass-fibre containing and unfilled polyamide 6,6, respectively. Moisture ingress, as would be expected, resulted in increased elongations to failure for the unfilled polymer but caused almost no variation in the elongation behaviour of the reinforced polymer.
Thermostabilisation of Polyisoprene by Phenol Grafting in Carbene Synthesis
Authors: Davydov E.Ya. , Pustoshnyi V.P. , Vorotnikov A.P. 
Published: March 2023

The comparison between traditional and grafted antioxidants shows that grafted antioxidants has qualitative advantages. DTBP produces the most promising results in the study. The results suggest that hindered phenols grafted by carbene synthesis on macromolecules will stabilise P.I. and other elastomers.
NDT of Composite Materials - Problems and Solutions 1. NDT as a Source of Information
Authors: Matiss I. 
Published: March 2023

This introductory paper is devoted to highlighting distinctive features of the non-destructive testing (NDT) techniques used in the study of polymers and composite materials. More than 30 years experience at the Institute of Polymer Mechanics has shown that success in the application of NDT to advanced materials depends crucially on the optimal choice of the technique and on the skill of the operator. The reason for a special approach to testing of these materials is that a number of specific features characterise composite structures. Analysis of these features, recommendations to increase the reliability and the accuracy of the NDT methods and a search for new testing techniques are the major areas of research carried out in the Institute. The following topics will be covered: 1. Non-destructive testing as a source of information. 2. Relaxation spectrometry for the structural study of polymers and polymer composites. 3. Modelling of dielectric relaxation phenomena.
Effect of Styrene Content and ZnO-Stearic Acid on the Dynamic Mechanical Properties of Electron Beam Vulcanised Styrene-Co-Butadiene Rubber
Authors: Abdel-Aziz M.M. , Youssef H.A. , Miligy A.A. El , Yoshii F. , Makuuchi K. 
Published: March 2023

The dynamic mechanical properties of electron beam vulcanized Styrene-Co-butadiene rubber (SBR) in presence of different additives over a wide temperature range were investigated. Also, the effect of HAF carbon black, the ZnO-Stearic acid system, and styrene content on the other mechanical properties was studied. It was found that, the more pronounced contribution from by ZnO was in SBR (23.5% styrene) where the storage modulus and damping as well as tensile strength, elongation, tear strength, hardness and abrasion resistance were remarkably improved. The high efficiency of ZnO toward SBR (23.5% styrene) compared with SBR (46% styrene) may be attributed to the enhancement of the crosslinking density as a result of there being more butadiene units in the former.
Readmission After COVID-19 for Late Acute Venous Thrombosis; CASE SERIES and Systematic Review of the Literature
Authors: Gómez Gutiérrez Oliver Antonio , McQuary Gabriel Salinas , Gonzalez-Urquijo Mauricio , Lozano Balderas Gerardo , Fabiani Mario Alejandro 
Published: March 2023

Objective Assess heterogeneity within patients with resolved COVID-19 to broaden the vision about post-discharge thrombotic cases and postulate possible related mechanisms in search of better anticoagulation guidelines. This study details patients’ characteristics, medical history, treatment, and outcomes of readmitted patients with late acute thrombosis through a systematic review of the literature and patients from our academic center database. Methods We extracted the records of patients readmitted for venous thrombosis complications after discharge from the database of the first 2000 patients admitted with COVID-19 in our academic center; we also performed a systematic review of the literature using the Medical Subject Headings terms “late thrombosis,” “COVID-19,” + “venous thrombosis” in PubMed and Google Scholar according to PRISMA guideline. Results The literature review found 20 patients suitable for review matching the inclusion criteria. These patients were added to those in our database, summing up a total of 26 patients. The median age was 50 years old, 76.9% were male, and most were overweight or had grade 1 obesity (n = 11, 42.3%). None had a previous thrombotic history, but 50% had an underlying comorbidity. Thrombotic events presented on a median of 20 days (range: 4-150 days) from discharge. Pulmonary embolisms occurred in 23 patients (88.46%), deep vein thrombosis in 4, mesenteric thrombosis, and cerebral venous thrombosis in 1, respectively. Conclusion This study found that most patients readmitted for thrombotic events after COVID-19 discharge were middle-aged men with Venous Thrombo Embolism events.
Incidence of barotrauma in patients with COVID-19 (alpha- and beta-predominant period) requiring mechanical ventilation: Single-center retrospective study
Authors: Donohue Kristina-Noel , Sivanushanthan Shankarapryan , Etling Emily , Hockstein Michael , Yohannes Seife , Clark Paul 
Published: March 2023

Objective: We sought to determine predictors, incidence, and interventions required for patients who developed barotrauma. Pneumothorax, subcutaneous emphysema, and pneumomediastinum have all been reported as complications related to COVID-19-positive patients requiring invasive mechanical ventilation. Methods: In this retrospective study, clinical and imaging data from COVID-19 patients were collected and reviewed by two independent intensivists between January 4, 2020 and January 10, 2020. Data were used to identify COVID-19-positive patients requiring invasive mechanical ventilation and the incidence of barotrauma. Two separate cohorts were created as non-injured (no barotrauma) and injured (barotrauma present). We then sought to identify the risk factors for barotrauma in the non-injured cohort on Days 0, 7, 10, and 14 after intubation and day of injury in the injured cohort. Results: Of the 264 patients with COVID-19, 55.8% were African American. The non-injured group was older (60 ± 15 versus 49 ± 16, p  = 0.006), with male predominance in the injured group versus non-injured group (75% versus 55%). A total of 16 (6.5%) patients developed one or more complications of barotrauma, defined as subcutaneous emphysema, pneumothorax, or pneumomediastinum. Length of stay was longer for the injured group versus non-injured group (47 versus 25 days). Plateau pressure ( p  = 0.024), fraction of inspired oxygen ( p < 0.001), and driving pressure ( p = 0.001) were statistically significant in injured cohort. Mortality rate in non-injured versus injured was 49.4% versus 69%. Using random effect model, fraction of inspired oxygen ( p = 0.003) and mean airway pressure ( p  = 0.010) were significant at the time of injury. When comparing alive versus deceased in the injured cohort, thoracostomy placement in alive versus deceased was 80% versus 54.5%. Conclusion: COVID acute respiratory distress syndrome patients requiring invasive mechanical ventilation had a higher rate of barotrauma and were younger than those who did not develop barotrauma. Possible interventions to be considered to decrease barotrauma are decreased driving pressure goal and universal use of esophageal balloon manometry.