bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure and Molecular Weight Determinations of Unsaturated Polyester Prepolymers by Steric Exclusion Chromatography
Authors: Leroux F. , Mortaigne B. , Belan F.
Published: May 2023

Four model unsaturated polyester prepolymers and two industrial resins were studied by size exclusion chromatography (SEC).

A calibration curve was set up with model resins and used to characterize the industrial unsaturated polyester resins. Weight average molecular prepolymer weights were determined from the new calibration curve. They were lower than those determined with polystyrene or epoxy calibration curves.

The observation of SEC chromatographs proves the formation of diol-ISO-diol (where ISO = isophthalic acid) and MAA-diol-MAA structures (where MAA = maleic anhydride) in the beginning of polycondensation reactions. This gives information on the future structure of the UP network.
Effects of Interleaving on the Impact and Impact Fatigue Responses of Cross-ply Carbon Fibre/Epoxy Laminates
Authors: Yuan Q. , Karger-Kocsis J.
Published: May 2023

The impact performance of carbon fibre/epoxy (CF/EP) laminates with and without interleaving was investigated by an instrumented falling weight impact (IFWI) method both in the perforation and the subperforation ranges. Tests in the subperforation range were performed either by single impacts with various energy levels or by multiple impacts (impact fatigue) at the same incident energy (Ein). In the former case both the maximum load (Fmax) and the maximum deflection (xmax) increased with increasing Ein. Under impact fatigue conditions the absorbed energy (Ea) and xmax increased, whereas Fmax decreased with increasing numbers of impacts (NOI). It was recommended to relate the stiffness deterioration of the plates to the change in the initial or secant slope of the rebound fractograms represented as F-x traces. The effects of position, number and thickness of the adhesive interlayers (A) incorporated were also studied. Positioning the interleaf in the neutral axis (mid-plane) of the composite plates does not enhance the resistance to delamination are low energy levels. In contrast, interleaving in the compression and/or tension sides of the plates depressed delamination, detected by ultrasonic C-scanning, considerably. The cone of damage across the thickness became narrower due to interleaving, as revealed by microscopic and ultrasonic B-scanning techniques.
Synthesis of Poly(methacrylic Acid)-Cellulose Composites Using Different Cellulosic Materials in the Presence of Potassium Permanganate and Activator
Authors: El-Sisi F.
Published: May 2023

Polymerisation of methacrylic acid (MAA) in the presence of cellulose pulps prepared from bagasse, rice, straw and cotton stalk was carried out under a variety of conditions. Potassium permanganate (KMnO4) was used as initiator, along with either citric acid or sodium thiosulphate (Na2S2O3) as activator. The polymerisation products, including grafted cellulose, homopolymer, ungrafted cellulose and oxidised cellulose in a polyblended form, is called “composite”. Major factors affecting the polymerisation reaction were studied. These encompass initiator, activator and monomer concentrations, duration and temperature of polymerisation as well as the nature of the cellulose substrate. Results for the percent polymer yield of the composite and those of the total conversion of monomer to polymer suggest appropriate conditions for the synthesis of poly (MAA)-cellulose composite as: [KMnO4], 0 08%; [Na2S2O3], 2.5 m.mole L; [MAA], 100% based on weight of sample; material to liquor ratio, 1:30; temperature, 70°C and time, 60 minutes. The effect of the nature of the cellulose on the properties and characteristics of the composite could be realised from the following orders:

(1) for the polymer yield, graft yield and swellability: bagasse > rice straw > cotton stalk;

(2) for carboxyl content: bagasse > cotton stalk > rice straw; (3) for solubility: rice straw > cotton stalk > bagasse.
The Protection of Aluminium Alloys in Harsh, Corrosive Environments by Oxidized Polyphenylene Sulphide Coatings
Authors: Sugama T. , Carciello N.
Published: May 2023

A moderate rate of oxidation of the sulphide groups in polyphenylenesulphide (PPS) played a key role in ensuring that PPS coatings adequately protect aluminium (Al) alloys from corrosion in wet, harsh environments. There are three major reasons for a good protective performance: 1) the superior hydrothermal stability of PPS itself, 2) the limited amount of sulphonic acid formed by the oxidation of sulphide, and 3) the formation of a discontinuous, intermediate layer of Al2(SO4)3 as the interfacial reaction product between A12O3 at the top surface of Al, and oxidized PPS. Widespread oxidation of PPS led to an increase in the rate of the interfacial interaction, forming sulphonic acid-enriched A12(SO4)3 intermediate layers, thereby improving the bond strength at Al-to-PPS adhesive joints. However, an overabundance of these reaction products resulted in an inadequate coating that failed to protect the Al during a long-term exposure in a harsh, corrosive environment because of the susceptibility of these salt products to dissolution in water.
Influence of Loading Mode and Hydrothermal Environment on the Contribution of the Interface to the Cohesion of Glass/Epoxy Composites
Authors: Krawczak Patricia , Pabiot José
Published: May 2023

The aim of this paper is to make clear the way the interface contributes to the cohesion of the composite by means of several macroscopic characterization methods (interlaminar shear strength, transverse tension with monitoring of acoustic emission, mode I and mode II fracture mechanics). The paper highlights the main parameters of influence, in particular the loading mode and the hydrothermal environment. Moreover the study made it possible to recommend certain characterization methods for the interface based on the variations in mechanical and physical parameters.
Micro-Organism Adhesion to Polymer Surfaces and its Role in Biodegradation
Authors: Gumargalieva K.Z. , Kalinina I.G. , Mironova S.N. , Zaikov G.E.
Published: May 2023

Fourier Transform infra red spectra of conidien microscopic fungi, capable of accumulating on and degrading polymers, have been studied, and an interpretation is provided. It is possible to define and predict their hydrophoby, which is the crucial factor in microorganism adhesion to solid (e.g. polymer) surfaces, and hence in biodegradation.
Properties of Fibres Spun from Blends of a Thermotropic Liquid Crystalline Block Copolymer with Poly(ethylene terephthalate)
Authors: Giesa Reiner , Joslin Scott , Melot Denis , Farris Richard J.
Published: May 2023

Triad4-co-PBT, a thermotropic liquid crystalline (TLCP) block copolyester has been blended with fibre grade poly(thylene terephthalate) (PET) to investigate the potential of in-situ fibre reinforcement. Fibres containing 5 to 80 wt.% TLCP were extruded and the effects of processing conditions were studied, e.g. spinning temperature and post treatment conditions. The fibres were evaluated for mechanical performance, dimensional stability (shrinkage) and development of shrinkage stresses. The optimal processing temperature for these blends was determined to be between 270 - 275°C based on mechanical performance and their fibre WAXS diffraction patterns. The optimal blend composition was found to be 10 wt.%. The highest modulus (19.8 GPa) was achieved with a 20 wt.% blend, but this system had a low ultimate strength (725 MPa) and numerous defects in the cold drawn fibre. A study of the post treatment process revealed that fibres drawn at 220°C exhibited increased thermal stability independent of TLCP content compared to those drawn at lower drawing temperature. Scanning electron microscopy of fractured fibre cross sections revealed a two phase morphology with the LCP phase dispersed as fine spherical particles
Shrinkage Control in Fibre Reinforced Polymers II: Epoxy Resins with Expanding Monomers
Authors: Piggott M.R. , Zhang X-D (David)
Published: May 2023

Experiments have been carried out with dinorbornene spiro ortho carbonate (DNSOC) to determine the extent to which this expanding monomer can be used to reduce the shrinkage stress in a moderately high Tg epoxy resin. Although the copolymers had good mechanical properties and past experience has shown that they can be used to make excellent fibre composites, the effect of the expanding monomer on shrinkage stress was small. Only about 7% of the monomer could normally be dissolved in the epoxy at 100°C, and this contributed only a very small shrinkage stress reduction. At the same time the Tg was reduced. The lack of useful effect is because high Tg polymers can normally only be produced by curing at high temperatures. During cure, most of the beneficial effect of the expansion disappears due to stress relaxation at the curing temperature. Hence, expanding monomers are not recommended for high performance composites for aerospace use.
Speciality Polymer Blends of Carboxylated Nitrile Rubber and Polyurethane Elastomers
Authors: Roy S.K. Singha , Das C.K.
Published: May 2023

Blends of polyurethane elastomers and carboxylated nitrile rubber, prepared by three different techniques in different blend ratios, have been studied. The properties of the blends were improved by blending with polyurethanes in a sulphur cured blend system. In the peroxide cure system the improvements occurred when the preblends were heated before incorporating curatives into it. Blend properties largely depend on the blend ratio and on the blending technique. IR spectra reveal that interchain crosslinking occurred between polyurethane and carboxylated nitrile rubber on heating, in the absence of curatives. The preheating of the blends before adding curatives improved the properties of the blends; the degradation process and weight loss were retarded. The extraction of the carboxylated nitrile rubber (XNBR) phase in the solvents was also restricted on preheating, due to interchain crosslinking.
Effect of Particles on the Wear and Friction of Glass Fibre Reinforced Plastic Composites
Authors: Srivastava V.K. , Pathak J.P.
Published: May 2023

The main work of the present research program is to study the wear and friction properties of mica and mica/zirconia filled unidirectional glass-fibre-reinforced epoxy resin composites as a function of the filler content and driving load. Wear and friction coefficient rate decrease with increasing filler contents. But the increase was found only after reaching the optimum ratio of filler and fibre-epoxy contents.
Macrokinetics of the Degradation of Polyesterurethanes in Model Biological Media
Authors: Trosteniuk N.V. , Gumargalieva K.Z. , Zaikov G.E.
Published: May 2023

The degradation of samples of thrombo-resistant films of segmented polyesterurethanes (Avcothane® and Biomer®) in water and acidic solutions (acidic phosphates) has been investigated. Avcothane, being the copolymer of a segmented polyurethane with polydimethylsiloxane, degraded in water at a noticeable rate, whereas biomer samples were hydrolytically stable. It was shown that degradation from the surface of the Avcothane samples is controlled by decomposition of the siloxane component, as a result of hydrolysis. The values of the decomposition rate constant obtained allowed the authors to predict the time required for degradation of the surface layers of polyesterurethane (Avcothane), responsible for the thromboresistance.
Studies on the Synthesis of Polyarylates with Allylic Side Groups. Part 2. Photocrosslinking of Polyarylates
Authors: Brzozowski Zbigniew K. , Zadrozna Irmina , Kowalczyk Tomasz , Syromyatnikov Vladimir S.
Published: May 2023

Copolyarylates obtained from bisphenol-A and its diallyl derivative formed with isophthaloyl chloride via interfacial polycondensation were investigated. Mechanical test results were used to monitor the process of photocrosslinking. Investigations revealed that the photocrosslinking efficiency of a new monoazide photoinitiator was greater than that of a bisazide. Photoinitiator mixtures were found to improve photocrosslinking relative to solutions containing a single photoinitiator.
Influence of Compatibilizer and Additives on the Mechanical Properties of Polyethylene-Polystyrene Blends
Authors: Simitzis J. , Paitontzis C. , Economides N.
Published: May 2023

Polymer blends were prepared based on three different types of LDPE (A.B.C) and polystyrene without or with compatibilizer (KRATON G-1652) and with the addition of a pigment Iriodin, for the improvement of the optical properties. The Brabender torque and the tensile properties of the polymer blends were determined, particularly, the yield stress σy, the ultimate tensile strength (e.g. the strength at break) σB and the ultimate elongation (elongation at break) εB. By factorial experimental design, factors A (proportion of LDPE/polystyrene) and B (proportion of compatibilizer) were found to be statistically significant while C (type of LDPE) has lower significance. The compatibilizer acts as a reinforcing agent in the polymer blend of LDPE and polystyrene, changing the stress-strain curve to a ductile behaviour, increasing the torque, σB and εB and decreasing σY. Graphite, which is contained in LDPE-A, acts as a reinforcing agent. Iriodin does not act as a reinforcing agent in the polymer blend but leads to a decrease of σB, and to an increase of torque. It does not influence the stress-strain curve much. The appropriate amount of compatibilizer is determined to be up to 20%. Iriodin improves the optical properties of polymer blends and compensates for their inferior mechanical properties.
Electro-Mechanical Properties of Conductive Epoxy Composites
Authors: Strümpler R. , Maidorn G. , Garbin A. , Ritzer L. , Greuter F.
Published: May 2023

The electrical resistivity of epoxy composites was studied during curing and heating of the cured material. The initial resistivity ρ of epoxy containing a metallic filler was in the range of 106 to 107 Ωm. During curing a sudden reduction of ρ by eight orders of magnitude was observed. The shrinkage of the polymer during cross-linking and the build-up of internal stresses results in a lower inter-particle contact resistance. The contraction can be reversed by heating up again. Around the curing temperature, the resistivity increased by six to eight orders of magnitude due to the expansion of the material. The resistivity increased progressively until the contacts between the particles were opened and the composite reached a high-ohmic state.
Environmental Durability of F/A-18 Graphite/Epoxy Composite
Authors: Chester R.J. , Baker A.A.
Published: May 2023

An environmental durability trial is being conducted on F/A-18 graphite epoxy composites at five tropical test sites in Australia and Malaysia. Two types of specimen have been exposed in the external tropical environment for periods of up to 9 years and measurements have been made of moisture absorption levels, fatigue durability and residual strength. The maximum level of moisture absorption recorded has been 1.0 wt%. Sandwich beam specimens representative of an aircraft structure, containing different types of damage or simulated repairs, have withstood over 106 fatigue cycles at close to nominal design limit load in the tropical environment. This result indicates that F/A-18 composite structure should be very durable under long term tropical conditions.
Simulation and Measurement of Reinforcement Deformation during Preform Manufacture
Authors: Long A.C. , Rudd C.D. , Blagdon M. , Kendall K.N. , Demeri M.Y.
Published: May 2023

The use of liquid moulding processes including resin transfer moulding (RTM) and structural reaction injection moulding (SRIM) is now becoming increasingly popular in the automotive industry. These processes involve the injection of liquid resin into a fibre preform, which may be comprised of several layers of reinforcement mats or fabrics. Structurally demanding applications usually rely on “zero-crimp” engineered fabrics consisting of two or more groups of fibres stitched together using embroidery techniques. Preform manufacture usually involves a matched mould forming process, in which layers of reinforcement are formed between rigid tools to the component geometry. This requires a degree of fibre movement and re-orientation which can have a significant effect on the resulting processing and mechanical properties. This paper describes the development of a kinematic deformation model to predict the distribution of fibres within the preform. An automatic strain measurement system is used to characterise fabric deformation, enabling the fibre orientations within three-dimensional preforms to be determined. This is applied to a number of generic geometries with increasing depth of draw, allowing the deformation characteristics of reinforcement fabrics to be established and testing the validity of the process model.
Stress, Holes and Chemicals: Environmental Effects on Carbon Fibre Reinforced PEEK Laminates
Authors: Pritchard Geoffrey , Randies Steven J.
Published: May 2023

Carbon fibre/PEEK laminates were immersed in several liquid chemical environments including aviation jet fuel, water, Skydrol hydraulic fluid, and dichloromethane. They were simultaneously subjected to tensile, flexural and (in some cases) compressive loads. Comparison experiments were performed with samples in dry air. The rate of sorption of the liquid environments into quasi- isotropic laminates containing small circular holes was studied as a function of the (constant) strain applied. The specimens were then broken in tension. Strength and modulus retention were noted. The nature and magnitude of the load and of the environment had little effect on the failure mode, but considerable effect on the strength retention, and damage was sometimes initiated in the vicinity of the holes. Critical strain levels for damage initiation in dichloromethane are reported. A few results are also reported for unidirectional laminates, without holes.
Structure-Performance Analysis of Two-Dimensional Woven Fabric Composites
Authors: Vandeurzen Philippe , Ivens Jan , Verpoest Ignaas
Published: May 2023

A revival of interest in woven fabric composites has been observed in recent years. However, our understanding of their elastic and strength behaviour is still in its infancy. Modelling starts with the creation of a three-dimensional geometric model of the fabric structure. This analysis results in a logical and automated partition of the unit cell into a number of micro-cells, and the prediction of local fibre volume fractions and yarn orientations. Through the application of a modified Fabric Geometry Model, the full set of elastic constants for the orthotropic material unit cell is obtained. A parametric study was performed to understand how the different geometric parameters of the fabric can be combined to determine the elastic behaviour of the composite material.
Effects of Structure and Microcracks on the Flexure, Interlaminar Shear and Impact Properties of Three-Dimensional Composites
Authors: Chou Shen , Chen Hong-En
Published: May 2023

Three-dimensional carbon fibre/epoxy resin composites were prepared, which had either three-axis or five-axis carbon fabrics (3D-3A or 3D-5A) in four woven gauges, and Teflon® was embedded in the fabric structures to initiate various types of microcracks. The flexural, interlaminar shear, and impact properties of these 3-D composites were studied. The results indicated that the flexural properties of 3D-3A were better than those of 3D-5A.

However, 3D-5A structures gave better impact strength compared to 3D-3A. The interlaminar shear strength depended on the weave gauge. The effect of microcracks on the properties of 3-D composites was generally kept within 10%, but transverse microcracks lowered the flexural properties of 3-D composites by 10–20%. The 3D-3A composites showed cracks along the interface between the Z axial bundles and the matrix, whereas the 3D-5A showed 45°-axial bundle pull-out.
Electron Beam Initiated Grafting and Crosslinking of Ethylene Vinyl Acetate Copolymer. Part II: Mechanical and Electrical Properties
Authors: Datta Sujit K. , Chaki Tapan K. , Khastgir D. , Bhowmick Anil K.
Published: May 2023

Mechanical, dynamic mechanical and electrical properties of electron beam modified ethylene vinyl acetate (EVA) copolymer in presence of trimethylolpropane trimethylacrylate (TMPTMA) and triallyl cyanurate (TAC) as sensitizer have been described. The tensile strength of the TMPTMA modified EVA increases with increase in radiation dose up to a certain level due to the development of network structure, while it does not change significantly for the TAC based system due to poor stress transfer. The tensile strength deteriorates sharply at higher radiation doses because of the predominating effect of breakdown of the network structure. However, the tensile strength changes marginally with TMPTMA level and decreases with an increase in TAC level. DMTA studies indicate mainly two transitions (namely γ and α) in the order of increasing temperature for both TMPTMA and TAC based samples. The γ-transition temperature shifts to higher values and the α-transition shifts to lower values with an increase in radiation dose due to modification of the main chain and to a decrease in crystallinity. Dielectric analysis shows a sharp transition at around -20°C for all uncured and cured samples due to movement of the highly polar acetate groups present in EVA. The loss factor decreases sharply at high temperature with increase in radiation dose due to crosslinking.
Cure of an Unsaturated Polyester Coating. Effect of Various Parameters
Authors: Salhi A. , Vergnaud J.M.
Published: May 2023

The cure of an unsaturated polyester coating was studied by using experiments and a model of the process. Experiments involved spraying the catalyst-resin mixture on a surface and following the hardness of the coating. The numerical model takes into account the heat transferred by convection at the surface of the coating and by conduction through the coating and the surface, as well as the heat generated by the cure reaction. The kinetics of heat evolved from the cure reaction was determined by calorimetry. The effect of various parameters, such as the temperature of the surrounding and the thickness of the coating was studied by considering the state of cure and the hardness.
Compatibilized Polyamide/Ultra High Molecular Weight Polyethylene Blends
Authors: Qiu Chun-Hai , Komppa Veikko , Sivola Arto
Published: May 2023

A study of the compatibilization of polyamide (PA)/ultra high molecular weight polyethylene (UHMWPE) blends by reactive processing has been initiated. Attention has been focused on the effect of compatibilization on the morphology and the mechanical and thermal behaviour of the resulting blend systems. A triblock copolymer, functionalized with maleic anhydride, has been found to have a profound effect on the properties of the blends. Compatibilized PA/UHMWPE blends combining the desirable properties of the two basic polymers will offer considerable development potential.
Opto-Thermal Properties of Fibres. Part 2: Investigation of Optical Parameter Changes in Annealed and Quenched Nylon 6-6
Authors: Fouda I.M. , Kabeel M.A. , El-Sharkawy F.M.
Published: May 2023

The changes in refractive indices and birefringence of nylon 6-6 fibres with different annealing conditions were” studied by interferometry. The polarizing interference microscope was used to determine the mean refractive indices and mean birefringence of these fibres. Also, an acoustic method has been used to measure densities. The results are used to calculate some structural parameters such as the form birefringence, virtual refractive index, harmonic mean polarisability of the dielectric, and the specific refractivity of the isotropic dielectric. Also, the number of monomer units per unit volume and the refractive indices of fully oriented fibre, when using monochromatic light vibrating parallel and perpendicular to the fibre axis, were calculated and found to be 1.5543 and 1.4723. The generalized Lorentz-Lorenz equation given by de Vries was used to determine nylon 6-6 fibre structural parameters. Comparisons between Herman's optical orientation function formula and the corrected formula by de Vries are given.
Some Durability Aspects of Thermoplastics for Oilfield Flexible Pipes
Authors: Campion Robert , Morgan Glyn , Samulak Michael
Published: May 2023

Some initial mechanical property, fatigue, high pressure (HP) methane permeation and explosive decompression data are reported for plasticized PVDF thermoplastics before and after various exposures in two fluids. The exposures were for different times and elevated temperatures, and were usually performed at 5000psi (345 bar). The fluids were a 97/3 methane/carbon-dioxide mixture saturated with water vapour, and 100% methanol, both of which induce some physical or physico-chemical changes in the material, but negligible chemical change. Thus measurements were made using reasonable simulations of fluids which could be met in oil production flexible pipe service.

Effects of ‘extra’ plasticisation by absorbed gas, deplasticisation of actual plasticizer, and ageing, are shown for some combinations. Arrhenius-type plots for HP methane permeation, allowing predictions of rates at other temperatures, and showing hydrostatic compaction effects, have been obtained: HP methane permeation rate is reduced by prior exposure to the methane/carbon-dioxide gas, but is increased in the presence of methanol.
Nucleation of Impact Modified Filled Polypropylene
Authors: Shanks Robert A.
Published: May 2023

Nucleation of polypropylene is important in determining its mechanical properties. Nucleation in polypropylene is nearly always found to be heterogeneous. Control is best achieved by addition of a nucleant. Addition of a filler can provide nucleation, as well as enhancing stiffness.

Formation of blends with other polymers can change nucleation depending on the partition of the nucleant between polypropylene and the other polymer, and the nucleant activity of the interface with the other polymer. Other crystalline forms can be obtained, depending on the crystallisation conditions and additives. For instance alpha and beta forms, and transcrystallinity occur. This paper reviews the interplay of these variables on polypropylene morphology and properties.
Insert Moulding - Automatic Manufacturing of Rubber-to-Metal and Rubber-to-Plastic Moulded Components
Authors: Arning Manfred
Published: May 2023

This report describes recent developments in automated manufacturing of engineering plastics components involving rubber-to-metal and rubber-to-plastic bonded parts. Examples are based on Engel machinery and experience. Specific features mentioned include tiebarless machines, software for cure time prediction, automated work cells, and microprocessor control systems. Specific examples of automated parts manufacturing are given.
Impact of Resolving Insolvency on Entrepreneurial Activity in India
Authors: Satyanarayana Puchakayala NVV , Ramanujam Veluchamy
Published: May 2023

The main purpose of this study was to analyse the impact of resolving insolvency on entrepreneurial activity in India. The study is empirical in nature and used the secondary source of data obtained from World Bank Reports for a period of 10 years from 2010 to 2019. Resolving insolvency is an explanatory variable, and entrepreneurial activity is a dependent variable. The resolving insolvency was expressed in terms of time to resolve insolvency, cost of resolving insolvency, recovery of creditors’ claims and strength of insolvency framework. Similarly, entrepreneurial activity was expressed in terms of total business density, new business density and closed business density of limited liability companies in India. It was presumed that the dimensions of resolving insolvency would influence entrepreneurial activity positively in India in a probabilistic manner. Both descriptive statistical measures, such as mean, median and standard deviation, and inferential statistical measures, such as multiple correlation and regression models, were used for data analysis. Adjusted R2 was used to test the model fitness, and Durbin–Watson test statistic was used to know whether auto-correlation exists. Eviews Statistical Software was used for this purpose. The study concludes that resolving insolvency has a positive impact on entrepreneurial activity in India but is of insignificant nature in the short run. The study further concludes that there are chances for a significant impact of resolving insolvency on the entrepreneurial activity in India in the long run. The level of significance may be increased if the number of observations and explanatory variables increases.
Race-Conscious Caring for Anti-racist Leadership: A Narrative Ethics for Cultivating Communal Responsibility
Authors: Gunzenhauser Michael G. , Flores Osly J. , Quigley Michael W.
Published: May 2023

Background -- Limited work has been done to integrate ethical leadership and anti-racist school leadership practice. Through narrative ethics, this paper links caring with race-consciousness to form a foundation for critical praxis. Purpose -- The authors address the limitations of caring leadership by arguing for a race-conscious narrative ethics that promotes communal responsibility for students, with specific attention to racialized and marginalized students. Research Design – This conceptual paper draws on caring theory, feminism, womanism, and culturally responsive leadership. The paper considers racism within a United States context, drawing from theory developed in additional contexts. Analysis – The paper builds from the limitations of caring theory and seeks alternative caring ethics from critiques and African-American historical struggles for sustainable and anti-racist praxis. Results -- The authors argue that predispositions toward caring among teachers and school leaders are insufficient for the project of anti-racist education because of uncritical assumptions of sameness, misplaced empathy, and the evasion of race and racism. The resulting impersonal caring reproduces racist power relations and reinforces standardized and competitive notions of responsibility for children, forestalling opportunities for collective action. Conclusions -- As an alternative to impersonal caring, the authors explore the possibilities of deepening leaders’ engagement in race-conscious caring through the significance of experience, the quality of caring relations, and the value of narrative ethics. A key implication is that race-conscious caring is necessary but insufficient for the work of anti-racism unless it informs changed practices, structures, and systems.
Xanthogranulomatous Ureteritis: A Diagnostic Challenge in a Patient with Bladder Cancer
Authors: Nova-Camacho Luiz M. , Val-Carreres Castellote Andrea , Villafruela Mateos Ainara
Published: May 2023

Xanthogranulomatous ureteritis is a very rare process characterized by the presence of foamy histiocytes in a background of chronic active inflammation affecting the ureteral wall. Herein, we describe a case of a 64-year-old man with bladder cancer affecting the left posterolateral wall of the bladder. Radiologically, there was a suspicion of multifocal involvement of the ureteral wall. The patient underwent a radical cystectomy with bilateral pelvic lymphadenectomy and a laparoscopic left nephroureterectomy. Histopathologic examination of the radical cystectomy revealed an invasive high-grade urothelial carcinoma. The wall of the left ureter was replaced by abundant foamy histocytes and a mixed inflammatory infiltrate with lymphocytes and plasma cells consistent with xanthogranulomatous ureteritis. In this report, we highlight the importance of awareness of this benign process when observing a ureteral mass in cancer patients.
Innovation Districts: Assessing Their Potential as a Strategy for Urban Economic Development
Authors: Drucker Joshua , Kayanan Carla Maria
Published: May 2023

Innovation districts have gained attention as a fast-spreading urban economic development strategy, raising numerous questions. What are their distinguishing attributes? Are they a substantive policy innovation? Are they likely to succeed in fostering innovation and economic dynamism? We propose a definition of innovation districts based on their characteristic features. Given the ambiguity of the term in practice, this is crucial for understanding and analyzing the strategy. We then evaluate innovation districts by applying theories and current understandings of the spatial and economic development aspects of innovation, entrepreneurship, and human capital, illustrating with examples from Boston, Detroit, Saint Louis, and San Diego. We conclude that the combination of components that comprises innovation districts is both new and valuable. Innovation districts present a potential pathway for advancing regional economic development goals via the pathways of innovation and entrepreneurship. We stress the importance of rigorous empirical evaluation and research regarding a variety of practical and strategic concerns.
Real-World Efficacy and Safety of Extended-Release Methylphenidate (PRC-063) in the Treatment of ADHD in Pediatric and Adult Subjects: Results of a Phase IV Multicenter Comparison With Lisdexamfetamine Dimesylate
Authors: van Stralen Judy , Parhar Gurdeep , Parhar Anita , Tourjman Valérie , Khattak Sohail , Ahmed Tahira , Donnelly Graeme A. E. , Ratz Jodan
Published: May 2023

Objective:

To evaluate the real-world efficacy, safety, and functional outcomes of PRC-063 (multilayer-release methylphenidate) versus lisdexamfetamine (LDX) in ADHD subjects in a phase IV, open-label study.

Method:

The primary endpoint was the change in the ADHD-DSM-5 Rating Scale (ADHD-5-RS) total score from baseline to Month 4. Secondary endpoints included a non-inferiority comparison between PRC-063 and LDX and measures of functioning and evening behavior.

Results:

One hundred forty-three pediatric and 112 adult subjects were enrolled. Mean ADHD-5-RS scores (standard deviation) were reduced in pediatric (−16.6 [10.4]) and adult (−14.8 [10.6]) subjects treated with PRC-063 ( p < .001). PRC-063 was non-inferior to LDX in the pediatric population but not in the adult population. Significant improvements were demonstrated in quality of life and functionality. Both medications were well-tolerated; more adverse events led to study discontinuation in pediatric subjects treated with LDX versus PRC-063.

Conclusion:

PRC-063 and LDX significantly improved ADHD symptomatology and functioning and were well-tolerated.
Class voting for radical-left parties in Western Europe: The libertarian versus authoritarian class trade-off
Authors: Steiner Nils D , Hoffeller Lucca , Gutheil Yanick , Wiesenfeldt Tobias
Published: May 2023

Which classes vote for radical-left parties (RLPs) in Western Europe? Previous research indicates that RLPs are strong among production workers and socio-cultural professionals, though not necessarily among both at the same time. Starting from the observation that these two classes take opposite stances on cultural issues, we trace variation in class voting back to RLPs’ positions on the cultural dimension. Combining voter-level data from the European Social Survey (2002–2018) with information on the positions of 23 RLPs from the Chapel Hill Expert Survey, we report robust evidence of a libertarian versus authoritarian class trade-off: RLPs with less libertarian positions receive relatively less support from socio-cultural professionals and relatively more support from production workers. These findings add to evidence that class voting varies with party positions. Ours is the first study to demonstrate this for RLPs, showing how, in the early 21st century, cultural positions matter for class voting.
Referential choice in two languages: The role of language dominance
Authors: Contemori Carla , Tsuboi Naoko , Armendariz Galaviz Alma L.
Published: May 2023

Aims and Objectives:

Bilingual speakers that speak a null subject (Spanish) and a non-null subject language (English) may show some indeterminacy in referential choice in their nondominant language in comparison to monolingual speakers. The present study tests the production of referring expressions in the two languages of bilingual speakers (Spanish and English) to assess attainment at the discourse level and explore the role of language dominance on referential choice.

Methodology:

A group of 49 Spanish–English bilinguals participated in a picture description task in English and Spanish measuring referential choice in contexts of reference maintenance and topic-shift.

Data and Analysis:

The results of our study show that at a group level, bilingual speakers produced more underspecified references in maintenance contexts than English monolingual speakers and produced more overspecified references in topic-maintenance and topic-shift contexts than Spanish monolingual speakers. The results further show that language dominance in the target language is associated with more monolingual-like referential choice.

Conclusions:

We discuss the role of language dominance in the development of bilingual referential choice patterns.
Prognostic analysis and nomogram establishment in patients with early esophageal cancer receiving endoscopic therapy: a population-based study
Authors: Sun Danping , Yi Jun , Gong Lingqi , Wu Yu , Liu Xiaowei
Published: May 2023

Background:

The growing numbers of early esophageal cancer (EEC) have increased the demand for endoscopic therapy.

Objectives:

To clarify the influential factors for the prognosis of patients with EEC receiving endoscopic surgery, and to construct a nomogram to evaluate the prognostic value of endoscopic therapy.

Design:

Prognostic analysis study.

Methods:

Clinical data of EEC patients who received endoscopic therapy between 2004 and 2015 were collected from the Surveillance, Epidemiology, and End Results database and used to construct the nomogram. The prognosis was analyzed by R language; the nomogram was constructed by Cox survival analysis; and the accuracy of the nomogram was verified by C index and the receiver operating characteristic (ROC) and calibration curves. X-Tile software was used to stratify the risk of patients.

Results:

Our study constructed the nomogram of the prognosis of patients with EEC treated by endoscopic surgery, including 1118 patients and 5 independent prognostic factors of esophageal cancer-specific survival. The C index and the area under the ROC curve (AUC) of the training and verification cohorts were all >0.75. The calibration curve also reflected the good consistency of the model in predicting survival. Significant difference in the risk of patients from different stratifications with the same T staging existed, and the model had a better C index than that of the T staging.

Conclusion:

Our study reports potential influential factors affecting the prognosis of EEC patients who received endoscopic therapy and establishes a reliable nomogram to predict the risk and prognosis, which has certain advantages compared with traditional TNM staging system.
FAIR data sharing: An international perspective on why medical researchers are lagging behind
Authors: Rainey Linda , Lutomski Jennifer E , Broeders Mireille JM
Published: May 2023

FAIR data, that is, Findable, Accessible, Interoperable, and Reusable data, and Big Data intersect across issues related to data storage, access, and processing. The solution-oriented FAIR principles serve an integral role in improving Big Data; yet to date, the implementation of FAIR in multiple sectors has been fragmented. We conducted an exploratory analysis to identify incentives and barriers in creating FAIR data in the medical sector using digital concept mapping, a systematic mixed methods approach. Thirty-eight principal investigators (PIs) were recruited from North America, Europe, and Oceania. Our analysis revealed five clusters rated according to perceived relevance: ‘Efficiency and collaboration’ (rating 7.23), ‘Privacy and security’ (rating 7.18), ‘Data management standards’ (rating 7.16), ‘Organization of services’ (rating 6.98), and ‘Ownership’ (rating 6.28). All five clusters scored relatively high and within a narrow range (i.e., 6.28–7.69), implying that each cluster likely influences researchers’ decision-making processes. PIs harbor a positive view of FAIR data sharing, as exemplified by participants highly prioritizing ‘Efficiency and collaboration’. However, the other four clusters received only modestly lower ratings and largely contained barriers to FAIR data sharing. When viewed collectively, the benefits of efficiency and collaboration may not be sufficient in propelling FAIR data sharing. Arguably, until more of these reported barriers are addressed, widespread support of FAIR data will not translate into widespread practice. This research lays the preliminary foundation for conducting targeted large-scale research into FAIR data practices in the medical research community.
Mental health support for and telehealth use by Australians living with borderline personality disorder during the onset of the COVID-19 pandemic: A national study
Authors: Heidari Parvaneh , Broadbear Jillian H , Brown Rita , Dharwadkar Nitin P , Rao Sathya
Published: May 2023

Objective

To investigate mental health service use and telehealth experience of people living with BPD in Australia during the first year of the COVID-19 pandemic.

Methods

An online survey was used to collect data from people who self-identified with a diagnosis of BPD.

Results

One hundred and sixty-nine survey responses were included in the analysis. More than half of participants acknowledged receiving information from their health service about resources that they could use if they become distressed. More than 70% of participants used telehealth for receiving mental health services; the majority used telehealth to consult a psychologist or to obtain prescriptions. Telehealth sessions were conducted over the phone, via videoconferencing, or using a mix of the two. While using telehealth, some participants found it more difficult to control their impulses to self-harm, to express thoughts about self-harm and suicide, to control feelings of anger, and to establish and maintain agreed treatment boundaries. Thematic analysis of participants’ experiences of telehealth identified five main themes: Communication challenges, Technology challenges, Privacy concerns, Benefits of telehealth, and Personal preferences.

Conclusion

The study findings revealed a variety of positive and negative consumer experiences. While the majority of participants found telehealth somewhat benefitted their mental health, challenges were also reported which raise concerns about the broader utility and effectiveness of telehealth.
Mental distress and virtual mental health resource use amid the COVID-19 pandemic: Findings from a cross-sectional study in Canada
Authors: Goodyear Trevor , Richardson Chris , Aziz Bilal , Slemon Allie , Gadermann Anne , Daly Zachary , McAuliffe Corey , Pumarino Javiera , Thomson Kimberly C , Jenkins Emily K
Published: May 2023

Objective

This paper characterizes levels of mental distress among adults living in Canada amid the COVID-19 pandemic and examines the extent of virtual mental health resource use, including reasons for non-use, among adults with moderate to severe distress.

Methods

Data are drawn from a cross-sectional monitoring survey (29 November to 7 December 2021) on the mental health of adults ( N  =  3030) in Canada during the pandemic. Levels of mental distress were assessed using the Kessler Psychological Distress Scale. Descriptive statistics were used to examine virtual mental health resource use among participants with moderate to severe distress, including self-reported reasons for non-use.

Results

Levels of mental distress were classified as none to low (48.8% of participants), moderate (36.6%), and severe (14.6%). Virtual mental health resource use was endorsed by 14.2% of participants with moderate distress and 32% of those with severe distress. Participants with moderate to severe distress reported a range of reasons for not using virtual mental health resources, including not feeling as though they needed help (37.4%), not thinking the supports would be helpful (26.2%), and preferring in-person supports (23.4%), among other reasons.

Conclusions

This study identified a high burden of mental distress among adults in Canada during the COVID-19 pandemic alongside an apparent mismatch between actual and perceived need for support, including through virtual mental health resources. Findings on virtual mental health resource use, and reasons for non-use, offer directions for mental health promotion and health communication related to mental health literacy and the awareness and appropriateness of virtual mental health resources.
Computer vision quantitation of erythrocyte shape abnormalities provides diagnostic, prognostic, and mechanistic insight
Authors: Foy Brody H. , Stefely Jonathan A. , Bendapudi Pavan K. , Hasserjian Robert P. , Al-Samkari Hanny , Louissaint Abner , Fitzpatrick Megan J. , Hutchison Bailey , Mow Christopher , Collins Julia , Patel Hasmukh R. , Patel Chhaya H. , Patel Nikita , Ho Samantha N. , Kaufman Richard M. , Dzik Walter H. , Higgins John M. , Makar Robert S.
Published: May 2023

Examination of red blood cell (RBC) morphology in peripheral blood smears can help diagnose hematologic diseases, even in resource-limited settings, but this analysis remains subjective and semiquantitative with low throughput. Prior attempts to develop automated tools have been hampered by their poor reproducibility and limited clinical validation. Here, we present a novel, open-source machine-learning approach (denoted as RBC-diff) to quantify abnormal RBCs in peripheral smear images and generate an RBC morphology differential. RBC-diff cell counts showed high accuracy for single-cell classification (mean AUC, 0.93) and quantitation across smears (mean R2, 0.76 compared with experts, interexperts R2, 0.75). RBC-diff counts were concordant with the clinical morphology grading for 300 000+ images and recovered the expected pathophysiologic signals in diverse clinical cohorts. Criteria using RBC-diff counts distinguished thrombotic thrombocytopenic purpura and hemolytic uremic syndrome from other thrombotic microangiopathies, providing greater specificity than clinical morphology grading (72% vs 41%; P < .001) while maintaining high sensitivity (94% to 100%). Elevated RBC-diff schistocyte counts were associated with increased 6-month all-cause mortality in a cohort of 58 950 inpatients (9.5% mortality for schist. >1%, vs 4.7% for schist; <0.5%; P < .001) after controlling for comorbidities, demographics, clinical morphology grading, and blood count indices. RBC-diff also enabled the estimation of single-cell volume-morphology distributions, providing insight into the influence of morphology on routine blood count measures. Our codebase and expert-annotated images are included here to spur further advancement. These results illustrate that computer vision can enable rapid and accurate quantitation of RBC morphology, which may provide value in both clinical and research contexts.