bluuebunny/crossref_metadata_2025 huggingface dataset:
Somatic Double Inactivation of NF1 Associated with NF1-Related Pectus Excavatum Deformity
Authors: Chelleri Cristina , Scala Marcello , De Marco Patrizia , Guerriero Vittorio , Ognibene Marzia , Madia Francesca , Guerrisi Sara , Di Duca Marco , Torre Michele , Tamburro Serena , Scudieri Paolo , Piccolo Gianluca , Mattioli Girolamo , Buffelli Francesca , Uva Paolo , Vozzi Diego , Fulcheri Ezio , Striano Pasquale , Diana Maria Cristina , Zara Federico
Published: April 2023

Neurofibromatosis type 1 (NF1) is a neurocutaneous genetic disorder with a broad spectrum of associated signs and symptoms, including skeletal anomalies. The association of NF1 with anterior chest wall deformities has been recently reported, especially the pectus excavatum (PE). Over the years, several authors have suggested loss of heterozygosity (LOH) as the possible pathogenic mechanism underlying the development of the typical NF1 skeletal features. Here, we report a NF1 patient with severe chest deformity and harboring the germline heterozygous pathogenic NF1 variant NM_001042492.3: c.4271delC p.(Ala1424Glufs

∗

4). Through next-generation sequencing (NGS), we investigated the affected cartilage from the PE deformity and identified the additional frameshift variant NM_001042492.3: c.2953delC p.(Gln985Lysfs

∗

7), occurring as a somatic NF1 second hit mutation. Exome sequencing confirmed the absence of additional variants of potential pathogenic relevance. Western blot analysis showed the absence of wild-type NF1 protein in the cartilage of the patient, consistent with a somatic double inactivation (SDI) of NF1. Taken together, our findings support the role of SDI in NF1-related PE, widening the spectrum of the pathophysiological mechanisms involved in NF1-related skeletal features.
Optimizing Numerous Influencing Parameters of Nano-SiO2/Banana Fiber-Reinforced Hybrid Composites using Taguchi and ANN Approach
Authors: Natrayan L. , Surakasi Raviteja , Patil Pravin P. , Kaliappan S. , Selvam V. , Murugan P.
Published: April 2023

High specific strength, strength-to-weight ratio, cheap cost, and other advantages, nanofillers are now the subject of most research on natural fibers. The current research’s main goal is to combine the Taguchi and artificial neural networks (ANN) approaches to maximize the mechanical characteristics of nanocomposites. The parameters: (i) nano-SiO2 wt%, (ii) banana fiber wt%, (iii) compression pressure in MPa, and (iv) compression molding temperature in °C were selected to achieve the objectives above. An L16 orthogonal array was used to optimize the process parameters based on the Taguchi technique. According to the intended experiment, mechanical characteristics, such as tension, bending, and impact strength, were assessed. The ANN was used to forecast outcomes that were optimized. The fiber mat thickness of banana fiber and the weight ratio of nano-SiO2 showed a considerable improvement in the mechanical characteristics of hybrid composites. According to the Taguchi technique, the most significant mechanical characteristics were 47.36 MPa tensile, 64.48 MPa flexural, and 35.33 kJ of impact under circumstances of 5% SiO2, 19 MPa pressure, and 110 °C. With 95% accuracy, ANN-predicted mechanical strength. The ANN forecast was more accurate than the regression model and experimental data. The above nanobased hybrid composites are mainly employed to satisfy the needs of the contemporary vehicle sector.
Woody Species Composition, Structure, and Regeneration Status of Gosh-Beret Dry Evergreen Forest Patch, South Gondar Zone, Northeast Ethiopia
Authors: Masresha Kassa Getinet , Getnet Deribie Addis , Chekole Walle Getnet
Published: April 2023

Owing to its variable topographic features, Ethiopia is endowed with rich biological resources. However, nowadays, these vital resources, mainly forests, are declining alarmingly, largely, due to agricultural expansion and energy consumption. This study was conducted at Gosh-Beret forest with the objective of investigating the status of forest species. Fifty-one main plots, spaced at a 100 m interval, were laid on north-south oriented transects. Within the main plots, five subplots, at each corner and center, were set to collect data for juveniles. In each plot, individuals of each woody species were identified and recorded. Percent cover abundance of each woody species per plot was genuinely estimated, which was later converted into the modified Braun–Blanquet scale. For each mature woody species, diameters at breast height (DBH ≥ 2 cm) were measured. Hierarchical cluster analysis was performed to identify community types. The Shannon–Wiener diversity index and Sorensen’s similarity coefficient were used to compare the species diversity and composition among communities, respectively. The structure and regeneration status of the forest species were analyzed using structural parameters and size-class ratios, respectively. A total of 52 woody species distributed in 35 families were recorded. Fabaceae, Euphorbiaceae, and Asteraceae were the most dominant families with 4 species each. The overall species diversity of the forest was 2.6, and five community types were generated from cluster analysis. In the study forest, frequency and density of species decrease with increasing frequency and density classes. Likewise, density of individuals in each class decreases as DBH classes increase. The total basal area of the forest was 19.81 m2ha−1, and the forest was at fair regeneration status with species having small IVI values and few/no seedlings. Therefore, immediate conservation measures are required to save species with small IVI values and few/no seedlings.
Carriers of Healing Agents in Biological Self-Healing Concrete
Authors: Tan Kun , Wu Shuncheng , Ding Shengduo
Published: April 2023

Concrete is the most widely used material in civil engineering, but due to its inherent brittleness, the generation of cracks easily occurs. Crack healing is an effective method for restoring the mechanical properties of concrete and improving its durability. Of all the current concrete crack healing methods, microbial-induced calcium carbonate precipitation technology is an incredibly promising crack self-healing strategy that has received widespread attention in the field of concrete crack repair. As the biological self-healing agent has difficulty resisting the high alkali and high calcium environment in concrete, protection is required when it is used in concrete cracks.
Long‐Term Optimal Operation of the Cascade Hydro‐Wind‐Photovoltaic Hybrid System considering Transmission Section Constraints
Authors: Su Huaying , Wei Huoqing , Wei Xingchen , Wang Guosong , Zhang Yan , Wang Rongrong
Published: April 2023

With the sharply increased development of variable renewable energy resources (VRERs) in recent years, the hydro‐wind‐photovoltaic (PV) hybrid system (HWPHS) has the prospective to enhance the grid integration of VRERs. Nevertheless, the intense variation associated with wind and PV generation causes uncertainties in the long‐term operation of the HWPHS. To overcome this drawback, this paper develops a novel method to derive adaptive operating rules for a cascade HWPHS. First, a scenario‐generating method coupling Kernel density estimation with the copula function is proposed to characterize the wind and PV forecast errors. Second, based on the power generation scenarios, an optimal scheduling model for the cascade HWPHS considering transmission section constraints is proposed to simulate the hydro‐wind‐PV complementary operation; finally, the long‐term operating rules for the cascade HWPHS are extracted by grey relational analysis and BP neural network. As a case study, the HWPHS of the Wu River basin in China is chosen. Results demonstrate that the proposed model can effectively utilize the flexibility of cascade hydropower stations, improve transmission section utilization efficiency, and promote clean energy absorption.
Supplementary Figures from Distinct Cell Adhesion Signature Defines Glioblastoma Myeloid-Derived Suppressor Cell Subsets
Authors: Bayik Defne , Bartels Cynthia F. , Lovrenert Katreya , Watson Dionysios C. , Zhang Duo , Kay Kristen , Lee Juyeun , Lauko Adam , Johnson Sadie , Lo Alice , Silver Daniel J. , McGraw Mary , Grabowski Matthew , Mohammadi Alireza M. , Veglia Filippo , Fan Yi , Vogelbaum Michael A. , Scacheri Peter , Lathia Justin D.
Published: April 2023

Supplementary figures 1-6
Supplementary Data from Distinct Cell Adhesion Signature Defines Glioblastoma Myeloid-Derived Suppressor Cell Subsets
Authors: Bayik Defne , Bartels Cynthia F. , Lovrenert Katreya , Watson Dionysios C. , Zhang Duo , Kay Kristen , Lee Juyeun , Lauko Adam , Johnson Sadie , Lo Alice , Silver Daniel J. , McGraw Mary , Grabowski Matthew , Mohammadi Alireza M. , Veglia Filippo , Fan Yi , Vogelbaum Michael A. , Scacheri Peter , Lathia Justin D.
Published: April 2023

Table1-2, figure legends
Desmoglein 2 Functions as a Receptor for Fatty Acid Binding Protein 4 in Breast Cancer Epithelial Cells
Authors: Chen Dongmei , Wirth Keith M. , Kizy Scott , Muretta Joseph M. , Markowski Todd W. , Yong Peter , Sheka Adam , Abdelwahab Hisham , Hertzel Ann V. , Ikramuddin Sayeed , Yamamoto Masato , Bernlohr David A.
Published: April 2023

Fatty acid binding protein 4 (FABP4) is a secreted adipokine linked to obesity and progression of a variety of cancers. Obesity increases extracellular FABP4 (eFABP4) levels in animal models and in obese breast cancer patients compared with lean healthy controls. Using MCF-7 and T47D breast cancer epithelial cells, we show herein that eFABP4 stimulates cellular proliferation in a time and concentration dependent manner while the non-fatty acid-binding mutant, R126Q, failed to potentiate growth. When E0771 murine breast cancer cells were injected into mice, FABP4 null animals exhibited delayed tumor growth and enhanced survival compared with injections into control C57Bl/6J animals. eFABP4 treatment of MCF-7 cells resulted in a significant increase in phosphorylation of extracellular signal-regulated kinase 1/2 (pERK), transcriptional activation of nuclear factor E2-related factor 2 (NRF2) and corresponding gene targets ALDH1A1, CYP1A1, HMOX1, SOD1 and decreased oxidative stress, while R126Q treatment did not show any effects. Proximity-labeling employing an APEX2–FABP4 fusion protein revealed several proteins functioning in desmosomes as eFABP4 receptor candidates including desmoglein (DSG), desmocollin, junction plankoglobin, desomoplankin, and cytokeratins. AlphaFold modeling predicted an interaction between eFABP4, and the extracellular cadherin repeats of DSG2 and pull-down and immunoprecipitation assays confirmed complex formation that was potentiated by oleic acid. Silencing of DSG2 in MCF-7 cells attenuated eFABP4 effects on cellular proliferation, pERK levels, and ALDH1A1 expression compared with controls.

Implications:

These results suggest desmosomal proteins, and in particular desmoglein 2, may function as receptors of eFABP4 and provide new insight into the development and progression of obesity-associated cancers.
Hearing Loss Related to Gene Mutations in Distal Renal Tubular Acidosis
Authors: Ay Ezgi , Gurses Emre , Aslan Filiz , Gulhan Bora , Alniacik Asuman , Duzova Ali , Bajin Munir Demir , Sennaroglu Levent , Genc Gulsum Aydan , Ozaltin Fatih , Topaloglu Rezan
Published: April 2023

Introduction: Distal renal tubular acidosis (dRTA) is a disease that may develop either primarily or secondarily, resulting from urinary acidification defects in distal tubules. Hearing loss may accompany primary forms of dRTA. This study aims to determine the characteristics of hearing loss due to different gene mutations in patients with dRTA. Methods: Behavioral and electrophysiological audiological evaluations were performed after otolaryngology examination in 21 patients with clinically diagnosed dRTA. Radiological imaging of the inner ear (n = 9) was conducted and results of genetic analyses using next-generation sequencing method (n = 16) were included. Results: Twenty-one patients with dRTA from 20 unrelated families, aged between 8 months and 33 years (median = 12, interquartile range = 20), participated. All patients with ATP6V1B1 mutations (n = 9) had different degrees of hearing loss. There was one patient with hearing loss in patients with ATP6V0A4 mutations (n = 6). One patient with the WDR72 mutation had normal hearing. Large vestibular aqueduct syndrome (LVAS) was detected in 6 (67%) of 9 patients whose radiological evaluation results were available. Conclusions: LVAS is common in patients with dRTA and may influence the type and severity of hearing loss in these patients. The possibility of both congenital and late-onset and progressive hearing loss should be considered in dRTA patients. A regular audiological follow-up is essential for the early detection of a possible late-onset or progressive hearing loss in these patients.
Enablers and Barriers of Healthcare Services for Community-Dwelling Elderly in Rural Indonesia: A Qualitative Evidence Synthesis
Authors: Aji Budi , Masfiah Siti , Anandari Dian , Intiasari Arih Diyaning , Widyastari Dyah Anantalia
Published: April 2023

Introduction: Healthcare services for elderly populations in Indonesia have been arranged in both institutional and community services. However, only a small number of elderly individuals reside in this residential aged care home setting because of cultural norms in Indonesian communities. Poor health infrastructure is still the main constraint, particularly in rural communities, although they have the adequate social capital to deal with restrictions. It is important to explore the existing implementation of healthcare services for elderly populations in rural Indonesia to shed light on appropriate policy interventions. This review aimed to identify and synthesize relevant evidence in Indonesia regarding the barriers and enablers of healthcare for elderly individuals in rural settings. Methods: This study used a qualitative evidence synthesis method. The search strategy aimed to locate published studies. An initial limited search of PubMed, Web of Science, ScienceDirect, Embase, PsycINFO, and CINAHL was conducted to identify articles on the topic that were published in English from 2010 to 2020. A meta-aggregation approach was used to pool qualitative study findings, employing JBI SUMARI software. Results: Four synthesized statements emerged from the study analysis: (1) integration needs among institutional and community-based healthcare for elderly people in rural areas, (2) the quality of integrated health services for elderly populations must be improved, (3) community support will improve and ensure the sustainability and implementation of community-based healthcare for elderly populations, and (4) community and family awareness must be improved to support care for the elderly. These were substantial insights that can be used to address key challenges in existing healthcare services and improve the system by considering specific features of enablers and barriers. Conclusion: A collaboration between communities, healthcare institutions, families, and government authorities was needed to support the success of the program and maintain the sustainability of services, which will result in adequate healthcare for the elderly population and improved health overall in rural Indonesia.
Agudización severa de EPOC: Abriendo la puerta para el desarrollo de herramientas y dispositivos simples
Authors: Sánchez-Bustillos Marco Hugo
Published: April 2023

Background: Left heart failure (LHF) is commonly associated with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) but its role is often underestimated. Aim of the study: To evaluate the performance of a new diagnostic technique based on the measurement of the pulse amplitude ratio (PAR) using non-invasive ventilation (NIV) for the early identification LHF in patients admitted to the emergency department (ED) for AECOPD. Results: 73 patients were included in this study: 32 in LHF group and 41 in non LHF- group. The two groups had comparable demographic and clinical characteristics at admission. The mean values of PARNIV was significantly higher among LHF patients (0.86 vs. 0.71; p < 0.01). The area under the receiver operating characteristic curve of PARNIV was 0.75. Using the best cut-off (0.6), the sensitivity of PARNIV was 93% with a specificity 21%, a positive predictive value of 48%, and a negative predictive value of 81%. Correlation between PARNIV and BNP was significant (r = 0.52; p = 0.002). Conclusion: Measurement of PARNIV in patients presenting to the ED with AECOPD had a good diagnostic performance for the detection of LHF and could represent an interesting alternative for the currently available methods. Trial registration: The study was registered in the Clinical Trial Registration System (clinicaltrials.gov) under the study number NCT05189119, https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S000BOO4&selectacti on=Edit&uid=U0000QAM&ts=2&cx=qrmluh.
Lungenultraschall vs. Röntgen-Thorax – ebenbürtige Diagnostik für Früh- und Neugeborene mit Atemnot?
Authors: Jorczyk Maximilian
Published: April 2023

Lung ultrasound (LUS) has become one of the most exciting applications in neonatal point of-care ultrasound (POCUS), yet still lacks routine clinical use. This study assesses the utility of LUS for neonatal respiratory disorders (NRDs) diagnosis and follow-up compared to chest X-ray (CXR). A prospective cross-sectional study was conducted on 100 neonates having NRDs with a gestational age ≥28 weeks, excluding those having multiple congenital anomalies, chromosomal aberrations, hydrops fetalis and/or heart failure. CXR and LUS were done on admission for diagnosis and were repeated after 7 days, or if needed earlier within the 7 days. The diagnosis of NRDs by CXR and LUS on admission and after 7 days was comparable (p > 0.05). LUS diagnosis sensitivity and specificity for respiratory distress syndrome, pneumonia, meconium aspiration syndrome, pneumothorax and pulmonary atelectasis were 94.7/100%, 97.5/95%, 92.3/100%, 90.9/98.9% and 100/97.8%, respectively. The total agreement between LUS and CXR was 98.5% with 95% CI (0.88 to 0.92). LUS and CXR had considerable agreement in the diagnosis of NRDs. Being a reliable bedside modality of diagnosis and safer than CXR, LUS may be considered an alternative method for the diagnosis of neonates with NRDs.
To memory of Daniil Sergeevich Aristov (1979–2022): biography and list of publications
Authors: RASNITSYN ALEXANDR P. , STOROZHENKO SERGEY YU.
Published: April 2023

On October 3, 2022, at the age of 43, the leading researcher of the Arthropod Laboratory of the Paleontological Institute of the Russian Academy of Sciences, Doctor of Biological Sciences Daniil Sergeevich Aristov (Figs 1, 2) died suddenly. He was born on January 27, 1979 in the city of Perm (former USSR) in a family of scientists. His father, Doctor of Physical and Mathematical Sciences Sergey Nikolayevich Aristov, worked as a chief researcher at the Ural Branch of the Russian Academy of Sciences, and his mother, Tatyana Aleksandrovna Aristova, was a linguist engineer and was engaged in scientific translation. As a child, Daniel was interested in biology, read a lot of popular science literature, and his favorite author was Gerald Malcolm Durrell. Daniil was a creative person: while studying at school, he went to the children’s painting studio and the creative workshop “Woodcarving” and participated with his works in exhibitions in Perm and other cities of Russia.
Duraznoscytinum aristovi gen. et sp. nov., a new scytinopterid (Hemiptera: Cicadomorpha) from the Upper Triassic of Argentina
Authors: LARA MARÍA B. , CARIGLINO BÁRBARA , ZAVATTIERI ANA M.
Published: April 2023

A new scytinopterid (Hemiptera: Cicadomorpha), Duraznoscytinum aristovi gen. et sp. nov., is described. The specimen was recovered from the upper section of the Potrerillos Formation (Upper Triassic) at the Quebrada del Durazno locality, south of the Cerro Cacheuta, Cuyana Basin, in Mendoza, Argentina. This represents the first record of a complete forewing (tegminous + clavus) of a scytinopterid for the Triassic of South America. Additionally, we briefly discuss the Triassic scytinopterid distribution worldwide, and provide preliminary morphological differences observed between the taxa recorded in the Southern Hemisphere. The new fossil described herein contributes to the knowledge on the hemipterofauna diversity present at the south of the Cerro Cacheuta area during Early Mesozoic times.
A new family of grylloblattids (Insecta: Grylloblattida) from mid-Cretaceous Burmese amber
Authors: STOROZHENKO SERGEY YU. , GRÖHN CARSTEN
Published: April 2023

The new grylloblattid family Aristoviidae Storozhenko & Gröhn fam. nov., with the type genus and species Aristovia daniili Storozhenko & Gröhn gen. et sp. nov., is described from the lowermost Cenomanian amber (Hukawng Valley, Kachin State, northern Myanmar). The new family is similar to the Permian-Triassic family Megakhosaridae and the Permian-Jurassic Blattogryllidae but differs from both by the shape of pronotum and wing venation. Aristoviidae fam. nov. is also similar to the extant family Grylloblattidae in body structure, but can easily be distinguished from it by the presence of ocelli, large compound eyes and wings, as well as the lack of the transverse furrow which separates the anterior part of pronotum from its posterior part. The phylogenetic relationships between families Megakhosaridae, Blattogryllidae, Grylloblattidae, and a new family are briefly discussed.
Redescriptions of the Triassic Notocupes beetles (Archostemata: Ommatidae) from Kyrgyzstan and South Kazakhstan
Authors: STRELNIKOVA OLESYA D. , YAN EVGENY V.
Published: April 2023

Four Triassic species of the ommatid beetles Notocupes are redescribed using an extended list of diagnostic characters from both published sources and original study. New diagnoses for the genus as well as for four Triassic species are provided with emphasis on discrete characters of cuticular sculpture and elytral venation. A brief overview of research history of Notocupes and of taxonomic issues associated with this species-rich genus is compiled. Several morphological characters useful for identification are discussed in detail, viz., body tubercles and their distribution on the body, main and intercalary elytral veins and pronotal shape.
An annotated checklist of the Collembola (Hexapoda) from Iran
Authors: MAYVAN MAHMOOD MEHRAFROOZ , GREENSLADE PENELOPE , SADEGHI-NAMAGHI HUSSEIN
Published: April 2023

Based on available literature sources, we have listed the genera and species of springtails (Collembola) of Iran located in Southwest Asia. In total, 301 named species of Collembola are listed in catalogue. This includes 286 described species in 109 genera from 20 families recorded from Iran. Of them, 15 species are also considered as dubious species. It also includes 15 genera whose species are still unknown. Information about biology, geographical distribution, ecology, authorship records for different provinces, and bibliographical data of Iranian Collembola are included.
Taxonomic review of Ctenodontina Enderlein, 1914 with the revalidation of Catostola Hull, 1958 (Diptera: Asilidae: Asilinae) and description of a new species
Authors: CAMARGO ALEXSSANDRO , VIEIRA RODRIGO , RAFAEL JOSÉ ALBERTINO
Published: April 2023

A taxonomic review of Ctenodontina Enderlein, 1914, was performed and only two species are included: Ctenodontina mochica Lamas, 1973 and Ctenodontina pectinatipes Enderlein, 1914. Catostola Hull, 1958 stat. rev., a genus that was previously allocated as junior synonym of Ctenodontina has its status revalidated and justifications for this nomenclatural act are presented. Consequently, seven species previously allocated in Ctenodontina were transferred to Catostola stat. rev.: Catostola baleta (Walker, 1849) comb. nov., Catostola carrerai Hull, 1958 comb. rev., Catostola complicata (James, 1953) comb. nov., Catostola martini (Fisher, 1992) comb. nov., Catostola maya (Carrera & d’Andretta, 1953) comb. rev., Catostola nairae (Vieira, 2012) comb. nov., and Catostola sagta (Vieira, Ayala-Landa & Rafael, 2017) comb. nov. All species were redescribed and illustrated, except Catostola carrerai Hull, 1958 comb. rev., and Ctenodontina mochica Lamas, 1973, for which only diagnosis were provided. A new species Catostola indecisa sp. nov., was described and illustrated. In addition, new distribution records were provided for Catostola baleta comb. nov., Catostola martini comb. nov., Catostola maya comb. rev., Catostola nairae comb. nov., and Catostola sagta comb. nov. An identification key to all species is provided including distribution maps with previous and new records.
Look (Act) East Policy and Northeast India: Reimagining the Space Through Institutional, Physical and Social Connectivity
Authors: Patgiri Rubul , Hazarika Obja Borah
Published: April 2023

The underdevelopment of Northeast India is quite often explained in terms of economic isolation primarily on account of its geographical peripherality. To address this challenge, a new imagination, through the Look (Act) East Policy has been proposed. This approach, makes India’s Northeast the centre of a unified economic, physical and social space through its integration with the trans-border neighbouring regions. In this article, an attempt has been made to examine the logic of developing an ‘extended Northeast’ and how it has been sought to be realized. The article argues that the actualization of this proposed integrated space is ridden with serious difficulties and the internal fragmentation of Northeast India and the exceptional rules and administrative arrangement that are in place in the region along with the geopolitical compulsion of India may act as significant barriers in this regard. And most importantly there are apprehensions that the proposed integrated space may lead to the appropriation of resources of the Northeast by the corporate houses without benefiting the people of the region.
Morphological Assessment of the Temporomandibular Joint in Asymptomatic Brachycephalic Dogs Using Computed Tomography
Authors: Paran Emilie , Bouyssou Sarah , King Alison
Published: April 2023

Temporomandibular joint (TMJ) incongruity and morphological variations can result in clinical signs but have also been reported in asymptomatic brachycephalic dogs. The purpose of this study was to assess TMJ morphology in a group of brachycephalic dogs using computed tomography (CT). French Bulldogs, English Bulldogs, Boxers, Cavalier King Charles Spaniels (CKCS), Chihuahuas, Lhasa Apsos, Pugs, Shih Tzus, and Staffordshire Bull Terriers were retrospectively enrolled. The severity of the TMJ morphological changes was determined using a modified 5-grade classification system. The intra- and inter-observer agreements were calculated. One hundred fifty-three dogs were included. When evaluating the medial aspect of the TMJ in the sagittal plane, there was a spectrum of variations in the shape of the head of the condylar process of the mandible, the mandibular fossa and the retroarticular process ranging from a rounded concave TMJ with a long retroarticular process to a flattened TMJ with an absent process. Variations in the articular surface of the head of the condyle in the transverse plane ranged from flat, through curved and trapezoid to sigmoid. The prevalence of severe TMJ dysplasia (grades B3 and C) in the CKCS and French Bulldog was high (69.2% and 53.8%, respectively). The intra- and inter-observer agreements were moderate. Variations in TMJ morphology exist in asymptomatic brachycephalic dogs. Marked changes seem to be highly prevalent in the French Bulldog and CKCS and should be considered a breed variation. The TMJ classification described in this study could be used to standardize assessment of canine TMJ morphology. However, further research is needed to determine its clinical application.
Dielectric Behaviour of Crosslinked Polyether Resins during Moisture Absorption
Authors: Barton S.J. , Pritchard G. , Vaezi-Nejad S.M.
Published: April 2023

The moisture absorption characteristics of a novel crosslinkable polyether of relatively low polarity have been determined. The relative permittivity (dielectric constant) was found to be 3.2 at 1 kHz and 22°C. This value is compared with that obtained for other polymers. Changes in relative permittivity following exposure to moisture were compared with corresponding changes in the epoxy resin system Epikote® 828/MPD. The polyether absorbs much less water than the epoxy, and the relative permittivity changes less during exposure to moisture. A Clausius-Mossotti calculation has been used to examine the free state polarisability of the absorbed water. The analysis suggested that absorbed moisture plasticises the polyether, producing a greater change in overall dielectric response than could be attributed to the water alone. In contrast the increase observed in epoxy resins is less than expected from the mass of moisture absorbed.
The Processability, Electrical and Mechanical Properties of EMI Shielding ABS Composites
Authors: Ma Chen-Chi M. , Hu A.T. , Chen D.K.
Published: April 2023

Conducting composite materials based on acrylonitrile-butadiene-styrene (ABS) compounded with conductive fillers, i.e. carbon black and aluminium flakes were prepared. The effectiveness of such composite materials with regard to shielding against electromagnetic interference (EMI) was studied, and the relationships among electrical conductivity, processability and mechanical properties were explored. Effects of modifying the filler surface with coupling agents on various properties were also investigated.

Results show that the threshold for conductivity is about 5 vol% (20wt%) of conductive carbon black or 5 – 10 vol% (20–40wt%) of Al-flake in composites. The most optimised shielding effectiveness reaching 25dB and 30 dB when the ABS matrix contains 20 wt% of carbon black or 40 wt% of Al-flake. This performance is comparable with that of 1 mm thickness of copper sheet, or that of nickel coating. In addition, both mechanical and rheological properties of the conductive composites were studied.
Biocompatibility and Biofunctionality of a Gelatin Impregnated Polyester Arterial Prosthesis
Authors: Chakfé Nabil , Marois Yves , Guidoin Robert , Deng Xiaoyan , Marois Michel , Roy Raynald , King Martin , Douville Yvan
Published: April 2023

The gelatin-impregnated vascular graft Gelseal® and its parent Triaxial® graft were evaluated in terms of biocompatibility in rats and in vivo biofunctionality as a thoraco-abdominal bypass in dogs. The biocompatibility study was performed by implantation of small segments of graft in the peritoneal cavity of rats for scheduled periods of upto 4 weeks. Peripheral total T cells (CD3), T helper cells (CD4) and T suppressor cells (CD8) and activated T cells expressing IL-2 receptors were quantified by cytofluorometry. Enzymatic and histopathological analyses of the tissue at the implant site were also performed. In the rat, the Gelseal® graft induced a significant reduction of CD4 cells at 3 days, 1 and 4 weeks post-implantation when compared to the control group (wounded rats without prosthesis). On the other hand, the Triaxial® graft showed similar results to the control group except for a significant reduction of CD4 cells after 1 week. The percentage of CD3, CD8 and activated T cells expressing IL-2 receptors were similar to the control group. There was no statistical difference in acid phosphatase activity in the tissue surrounding the Gelseal® and the Triaxial® grafts. Histological studies of the impregnated graft have revealed an inflammatory reaction with polymorphonuclear cells which lasted slightly longer than the 2 weeks observed for the non-impregnated polyester control. Thereafter, the inflammatory response of both grafts became chronic and moderate.

The investigation of in vivo biofunctionality was carried out by implanting the grafts as a thoraco-abdominal bypass in dogs for prescheduled periods of up to 6 months. The grafts were investigated for patency, morphology, healing sequerice, fibrin and platelet uptake and prostaglandin secretion. The healing characteristics of the Gelseal® graft were similar to the preclotted control. All grafts remained patent, and the small differences in platelet and fibrin uptake on the luminal surface between the impregnated and non-impregnated grafts were not statistically significant. The two healing sequences were also similar with the development of a collagenous internal capsule at 2 weeks post-implantation followed by the laying-down of endothelial-like cells at 1 month. The gelatin coating had completely eroded within the first month, at which time the PGI 2/ TXA 2 ratios determined on whole segments of grafts was higher than one.

The Gelseal® graft has shown good biocompatibility and excellent healing characteristics as a thoraco-abdominal bypass in dogs and compares favourably with its parent graft the Triaxial® polyester prosthesis.
Amorphous and Semi-Crystalline Nylon-6: Processing and Properties
Authors: Avramova Nadka
Published: April 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.
Preparation and Characterisation of “Cellulose/Ethylene Glycol Dimethacrylate/Acrylic Acid Cation Exchange Resins”
Authors: Abo-Shosha M.H. , Ibrahim N.A.
Published: April 2023

“Cellulose/ethylene glycol dimethacrylate/acrylic acid” cation exchange resins were prepared by bulk polymerisation of acrylic acid/ethylene glycol dimethacrylate (EGDMA) mixtures in presence of cellubse using ammonium peroxydisulphate as an initiator. Factors affecting the formation of the resins, such the concentration of each of ammonium peroxydisulphate, acrylic acid and EGDMA as well as polymerisation temperature were reported. Two cation exchange resins, of different capacities, were selected for characterisation by investigating their potentiometric titrations, water solubility, and swelling index as well as durability.
Predicting the Operating Characteristics and Play of Machine Sliding Bearings Made from Composite Materials
Authors: Levin Eng A.L. , Kacevman Eng
Published: April 2023

Polymer sliding materials are being used more and more in combinations of machine parts. The sliding properties and other characteristics of thermoplastics (acetal resins, polyamides) are temperature dependent. The main limitation of thermoplastic sliding bearings is the temperature. Calculation of the load capacity of thermoplastic sliding bearings should therefore form the basis for the thermal calculation of the sub-assembly, the purpose of which is to determine the operating temperature of the sub-assembly or (at a given permissible operating temperature) to determine the permissible operating parameters for the thermoplastic sliding bearing in the sub-assembly in question. Because of the low heat conduction and high thermal expansion coefficients of polymers, there are certain difficulties with heat dissipation through the bearing and the permissible tolerances when using thermoplastic sliding bearings.

On the basis of algorithms developed for the purpose, a program package has been developed to calculate the strength and stiffness of thermoplastic sliding bearings made from the most varied of materials. This presentation points out certain graphic dependences, determined with a plotter, of the initial dimensions on material properties and sub-assembly design.

Analysis of these relationships together with others determined during these machine experiments leads to the conclusion that the greatest efficiency can be achieved by simultaneously increasing the thermal conduction of the composite material by two to two and a half times and reducing the coefficient of friction to two thirds of the original value. By adding graphite fibres, the coefficient of thermal expansion can be reduced by 35%. This parameter has a decisive effect on the magnitude of the play in the sliding combination.
FRP Corrosion Resistance: The Role of the Glass Fibre Type
Authors: Santrach Drago , Matzeg Rick
Published: April 2023

The corrosion resistance studies of glass fibre reinforced plastics (RP) have primarily compared the resins and the surfacing veil materials using the ASTM C581 standard test method. As the corrosion barrier has been shown to delay and not stop the acid attack on the structural layers of the laminate, the more recent papers, by several authors, highlight the importance of the reinforcing fibres. In particular, the use of ECRGLAS® fibres is recommended in RP laminates subjected to the simultaneous stresses of mechanical loading and exposure to dilute material acids. A brief overview of the most pertinent literature related to the present work is given.

The experimental data on the resistance of RP laminates to corrosion attack in aqueous solutions of both sodium hydroxide and sulphuric acid is discussed. This work comprises a two level fraction factorial experiment design to study five factors: the glass fibre type (E vs. E-CR), the resin type (isophthalic vs. bisphenol A), the laminate construction (mat/mat/mat vs. mat/woven roving/mat), the exposure media type (sodium hydroxide vs. sulphuric acid) and the acid/base ion concentration (IN vs. 2N).

The laminates are compared using mechanical properties, and their retention, after exposure to the corrosive environments for up to 4 years.

Analysis of this study shows that E-CR glass offers improved performance compared to E glass in both environments. E-CR glass is significantly more resistant to sulphuric acid attack over long term exposure. In sodium hydroxide, E-CR glass performs better than E glass in the short term of up to 10 months. Neither glass type is able to resist sodium hydroxide attack in the long term. The resin type also plays a significant role in the corrosion resistance but mainly in the long run and primarily insodium hydroxide medium. The ion concentration and the laminate type are much less significant. The two glass types are also compared using C581 methodology. Again, E-CR outperforms E glass in the acidic environment and this effect increases with the increase in the exposure time.

ECRGLAS® is a registered trademark of Owens-Corning Fiberglas Corporation. Fiberglas Canada Inc. is a registered user.
Zinc Acrylate and Other Solid Monomers as Crosslinking Agents for Unsaturated Polyesters*
Authors: Krolikowski Waclaw , Nowaczek Wieslawa , Penczek Piotr , Rudnik Ewa
Published: April 2023

The peroxide-initiated, copolymerisation of an unsaturated polyester with zinc acrylate, diallyl phthalate prepolymer and a solid vinyl ester resin was investigated. The curing was followed by means of gelation curves and differential scanning calorimetry. The studies showed that zinc acrylate has the highest reactivity.
Styrene Crosslinked Vinylesters II: Water Sorption, Water Diffusion and Cohesive Properties
Authors: Bellenger V. , Verdu J. , Ganem M. , Mortaigne B.
Published: April 2023

The sorption characteristics (water equilibrium concentration W m and coefficient of diffusion D) were determined gravimetrically for six styrene crosslinked vinylester networks at 30, 40 and 50°C, 95 % RH.

The equilibrium water concentration (0.5 -1.8% by weight) is independent of the temperature and appears to be closely related to the concentration of polar groups (especially hydroxyls) in the polymer. It is an increasing function of the solubility parameter. The water diffusivity is of the same order of magnitude as that of unsaturated polyesters but considerably higher than that of hydrophilic amine crosslinked epoxies. There is no apparent correlation between D and volumetric properties such as the packing density, crosslink density or local mobility determined from viscoelastic spectra. In contrast, the fact that D is a decreasing function of the hydrophilicity for all the systems under consideration (including unsaturated polyesters and epoxies) seems to indicate that water diffusion is kinetically controlled by the strength of polymer-water interactions.
Novel All-Hydrocarbon Thermosetting Resins as Matrix Materials for Carbon and Glass Fibre Composites Materials I: Reinforcements
Authors: Muthiah Jeno , Mathias Lon J.
Published: April 2023

An all-hydrocarbon resin was synthesized using commercially available materials. The resin undergoes spontaneous cure at around 200°C and cationic cure at around 100°C. This resin gives composites with excellent properties when used with glass and carbon fibres. Flexural modulus values (DuPont DMA) of ca 66 GPa were obtained for carbon fibre composites compared to 42 GPa for epoxy/carbon composites made in our laboratories using commercially available materials. The modulus value at 300°C dropped to 10% of the room temperature value for epoxy composites, whereas the new material maintained 60% of its room temperature value. When brought back to ambient temperature, the modulus value had increased to 81 GPa for the new resin samples while that of the epoxy composite dropped to 23 GPa, Glass fibre composites with the new resin performed similar to the analogous epoxy material up to 200°C but maintained their properties up to 300°C while those of the epoxy composite were drastically reduced. Boiling water treatment had a large affect on the epoxy-glass samples but no observable affect on the glass composites made with the new resin. Scanning electron micrographs showed bonding of the new resin to both carbon and glass fibre surfaces. TGA analysis of both resin and composites showed decomposition beginning at 375°C. This new thermosetting resin thus offers a low-cost approach to glass and carbon composites possessing excellent thermal and physical properties, and out standing hydrolytic stability.
The Influence on their Resilience of a Partial Removal of the Deforming Stress on Compressed Elastomers
Authors: Tobisch K.
Published: April 2023

If there is a relatively low reduction in the original deforming stress applied to an elastomer seal which is subjected to a constant compression during its practical use, this may result in a considerable drop in its resilience and the sealing capacity associated with this. The degree of the stress relaxation caused by a specific reduction in the initial deforming stress in addition to the viscoelastic and ageing processes in the elastomer was determined for six vulcanisates and a thermoplastic elastomer during long-term storage at 23, 70 and 1000°C. The stress relaxation values determined in this way were compared to the results of stress relaxation tests performed according to DIN 53 537 (method B). In parallel to the relaxation measurements, a determination was made of the compression set which is obtained if the heated and deformed test pieces are cooled to room temperature in the clamping device before the stress is removed.
Grafting of Methacrylic Acid to Loomstate Viscose Fabric Using KMnO4/NaHSO3 System
Authors: EL-Rafie M.H. , Hafiz S.A. Abdel , Hassan S.M. , Hebeish A.
Published: April 2023

Potassium permanganate/sodium bisulphite redox system induced polymerization of methacrylic acid (MAA) with viscose fabric was studied under a variety of conditions. The polymerization reaction was studied with respect to graft yield, homopolymer, total conversion and graft efficiency. Results obtained indicated that increasing the MAA concentration, duration and temperature of polymerization enhances the graft yield, total conversion and homopolymer. Similar situations were encountered with KMnO 4 and NaHSO 3 concentrations but up to a certain limit after which these polymerization criteria decrease Meanwhile, the graft efficiency exhibits different maxima, depending upon the factors determining the polymerization reaction. Conversely, all the polymerization criteria decrease as the liquor ratio increases. A tentative mechanism for the polymerization reaction is also reported.
Radial Diffusion in a Sphere with Subsequent Change in Dimension. Desorption with a Finite Surface Coefficient of Mass Transfer in an Infinite Volume
Authors: Bakhouya-Sabbahi N. , Bouzon J. , Vergnaud J.M.
Published: April 2023

The liquid located in a polymer evaporates by following a process controlled by diffusion-evaporation. The general case when the desorption is followed by subsequent shrinkage is studied by considering a spherical polymer with a radial diffusion and a finite rate of evaporation. The volume of the surrounding is so large that it can be considered as infinite. The mathematical treatment is achieved, leading to general equations of radial diffusion and evaporation with a following change in dimension of the polymer. These general equations reduce to the Fick's equation when the amount of substance transferred is small enough. These general equations have no analytical solution, and the problem is resolved by using a numerical method with finite differences. The following parameters are of interest: the diffusivity, the coefficient of mass transfer on the surface, the radius of the empty bead, the relative volume expansion of the polymer due to the presence of the diffusing substance.