bluuebunny/crossref_metadata_2025 huggingface dataset:
Local Governance Capacity Needs for Implementing Climate Change Adaptation in Seychelles: An Assessment Based on the Capital Approach
Authors: Etongo Daniel , Gill Kelsy
Published: October 2022

As a Small Island Developing State, Seychelles is disproportionately affected by climate change, and enhancing her adaptive capacity is a national priority. Identifying and integrating local capacity needs into policy measures can improve multilevel governance and the effective implementation of National Adaptation Plans (NAPs), given that local governments have contextual knowledge about their territories and the climate change challenges affecting them. Based on the Capital Approach Framework (CAF), this study carries out an analysis of local governance capacity needs for implementing climate change adaptation in Seychelles. Data were collected using two methods: (i) questionnaire-led interviews among twenty-four district administrators (DAs), and (ii) an interactive workshop involving thirty-one participants, of which twenty-six were DAs and five were members of the National Climate Change Committee. The CAF was measured in two ways: (i) through descriptive statistics such as frequencies based on interview data, and (ii) through the ranking of types of capital to assess their weightings across four categories using a consensus approach during the participatory workshop. The findings of this study indicate significant political, financial, and human resource capacity gaps, which collectively hinder local adaptation. The critical shortcomings identified include the low participation in national-level decision-making processes, the inability to access external funding sources, and the lack of technical know-how. Through a participatory approach involving the local government representatives and the National Climate Change Committee, ten recommendations for policy measures that can enhance the effectiveness of local governance in climate change adaptation were co-developed. Seven of these recommendations partly address issues related to political capital. These recommendations highlight that a siloed approach cannot effectively address the impacts of climate change. For example, one of the recommendations stated that land-use planning should be guided by location-specific vulnerabilities, as these differ across districts.
Spotlight: An Interview with Dr. Christopher A. Lowry, on the Convergence of Microbes, Nature, and Mental Health
Authors: Logan Alan C. , Lowry Christopher A.
Published: October 2022

In the ongoing series of spotlight interviews, Challenges Advisory Board member and Nova Institute for Health Fellow, Alan C. Logan, meets with thought leaders, scientists, scholars, healthcare professionals, artisans, and visionaries concerned about health at scales of persons, places, and the planet. Here in this interview, Dr. Christopher A. Lowry of the University of Colorado Boulder, responds to a set of questions posed by Challenges. For nearly twenty years, Dr. Lowry has been at the forefront of the research connecting the microbiome to mental health. Ten years ago, Dr. Lowry and his colleagues wrote a provocative article under the title ‘Can we vaccinate against depression?’; Dr. Lowry updates Challenges on where the field has moved, with its promises and possibilities. Dr. Lowry reflects on the early influences that shaped his interest in the field and discusses the ways in which microbiome sciences are casting light on the many interconnected challenges of our time.
Adsorption Properties and Hemolytic Activity of Porous Aluminosilicates in a Simulated Body Fluid
Authors: Golubeva Olga Yu. , Alikina Yulia A. , Brazovskaya Elena Yu. , Vasilenko Nadezhda M.
Published: October 2022

A study of the adsorption features of bovine serum albumin (BSA), sodium and potassium cations, and vitamin B1 by porous aluminosilicates with different structures in a medium simulating blood plasma was conducted. The objects of this study were synthetic silicates with a montmorillonite structure Na2x(Al2(1-x),Mg2x)Si4O10(OH)2·nH2O (x = 0.5, 0.9, 1), aluminosilicates of the kaolinite subgroup Al2Si2O5(OH)4 with different particle morphologies (spherical, nanosponge, nanotubular, and platy), as well as framed silicates (Beta zeolite). An assessment of the possibility of using aluminosilicates as hemosorbents for extracorporeal blood purification was carried out. For this purpose, the sorption capacity of the samples both with respect to model medium molecular weight toxicants (BSA) and natural blood components—vitamins and alkaline cations—was investigated. The samples were also studied by X-ray diffraction, electron microscopy, and low-temperature nitrogen adsorption. The zeta potential of the sample’s surfaces and the distribution of active centers on their surfaces by the method of adsorption of acid-base indicators were determined. A hemolytic test was used to determine the ability of the studied samples to damage the membranes of eukaryotic cells. Langmuir, Freundlich, and Temkin models were used to describe the experimental BSA adsorption isotherms. To process the kinetic data, pseudo-first-order and pseudo-second-order adsorption models were used. It was found that porous aluminosilicates have a high sorption capacity for medium molecular weight pathogens (up to 12 times that of activated charcoal for some samples) and low toxicity to blood cells. Based on the obtained results, conclusions were made about the prospects for the development of new selective non-toxic hemosorbents based on synthetic aluminosilicates with a given set of properties.
The Prevalence of Liver Cytolysis in Children with Helicobacter pylori Infection
Authors: Lupu Ancuta , Miron Ingrith Crenguta , Cianga Anca Lavinia , Cernomaz Andrei Tudor , Lupu Vasile Valeriu , Gavrilovici Cristina , Stârcea Iuliana Magdalena , Tarca Elena , Ghica Dragos Catalin , Fotea Silvia
Published: October 2022

(1) Background: The relationship between Helicobacter pylori (H. pylori) infection and liver disease has been discussed for many years, but the association between the infection and liver cytolysis in children has been insufficiently explored. In our study, we evaluate this relationship in a pediatric population from the northeast of Romania. (2) Methods: A retrospective study of children with H. pylori infection and liver cytolysis was conducted on a group of 1757 children, admitted to a pediatric gastroenterology regional center in northeast Romania over 3 years. (3) Results: Liver cytolysis syndrome was present in 112 children of both sexes. Of the 112 children, 20 children (17.9%) also had H. pylori infection. In the statistical analysis, we noted a significant association between liver cytolysis syndrome and H. pylori infection (χ2; p < 0.001). (4) Conclusions: This relationship requires further in-depth studies that also consider certain parameters that may influence the results of these correlations. In addition, we point out the need for further analyses evaluating, in terms of the histopathological changes in each liver disease, the efficacy of H. pylori eradication.
Process-Oriented Profiling of Speech Sound Disorders
Authors: Diepeveen Sanne , Terband Hayo , van Haaften Leenke , van de Zande Anne Marie , Megens-Huigh Charlotte , de Swart Bert , Maassen Ben
Published: October 2022

The differentiation between subtypes of speech sound disorder (SSD) and the involvement of possible underlying deficits is part of ongoing research and debate. The present study adopted a data-driven approach and aimed to identify and describe deficits and subgroups within a sample of 150 four to seven-year-old Dutch children with SSD. Data collection comprised a broad test battery including the Computer Articulation Instrument (CAI). Its tasks Picture Naming (PN), NonWord Imitation (NWI), Word and NonWord Repetition (WR; NWR) and Maximum Repetition Rate (MRR) each render a variety of parameters (e.g., percentage of consonants correct) that together provide a profile of strengths and weaknesses of different processes involved in speech production. Principal Component Analysis on the CAI parameters revealed three speech domains: (1) all PN parameters plus three parameters of NWI; (2) the remaining parameters of NWI plus WR and NWR; (3) MRR. A subsequent cluster analysis revealed three subgroups, which differed significantly on intelligibility, receptive vocabulary, and auditory discrimination but not on age, gender and SLPs diagnosis. The clusters could be typified as three specific profiles: (1) phonological deficit; (2) phonological deficit with motoric deficit; (3) severe phonological and motoric deficit. These results indicate that there are different profiles of SSD, which cover a spectrum of degrees of involvement of different underlying problems.
SCN1B Genetic Variants: A Review of the Spectrum of Clinical Phenotypes and a Report of Early Myoclonic Encephalopathy
Authors: Zhu Zahra , Bolt Elizabeth , Newmaster Kyra , Osei-Bonsu Wendy , Cohen Stacey , Cuddapah Vishnu Anand , Gupta Siddharth , Paudel Sita , Samanta Debopam , Dang Louis T. , Carney Paul R. , Naik Sunil
Published: October 2022

Background: Pathogenic variants in SCN1B, the gene encoding voltage-gated sodium channel b1/b1B subunits are associated with a spectrum of epileptic disorders. This study describes a child with early myoclonic encephalopathy and a compound heterozygous variant in the SCN1B gene (p.Arg85Cys and c.3G>C/p.Met1), along with the child’s clinical response to anti-seizure medications (ASMs) and the ketogenic diet. We reviewed the current clinical literature pertinent to SCN1B-related epilepsy. Methods: We described the evaluation and management of a patient with SCN1B-related developmental and epileptic encephalopathy (DEE). We used the Medline and Pubmed databases to review the various neurological manifestations associated with SCN1B genetic variants, and summarize the functional studies performed on SCN1B variants. Results: We identified 20 families and six individuals (including the index case described herein) reported to have SCN1B-related epilepsy. Individuals with monoallelic pathogenic variants in SCN1B often present with genetic epilepsy with febrile seizures plus (GEFS+), while those with biallelic pathogenic variants may present with developmental and epileptic encephalopathy (DEE). Individuals with DEE present with seizures of various semiologies (commonly myoclonic seizures) and status epilepticus at early infancy and are treated with various antiseizure medications. In our index case, adjunctive fenfluramine was started at 8 months of age at 0.2 mg/kg/day with gradual incremental increases to the final dose of 0.7 mg/kg/day over 5 weeks. Fenfluramine was effective in the treatment of seizures, resulting in a 50% reduction in myoclonic seizures, status epilepticus, and generalized tonic-clonic seizures, as well as a 70–90% reduction in focal seizures, with no significant adverse effects. Following the initiation of fenfluramine at eight months of age, there was also a 50% reduction in the rate of hospitalizations. Conclusions: SCN1B pathogenic variants cause epilepsy and neurodevelopmental impairment with variable expressivity and incomplete penetrance. The severity of disease is associated with the zygosity of the pathogenic variants. Biallelic variants in SCN1B can result in early myoclonic encephalopathy, and adjunctive treatment with fenfluramine may be an effective treatment for SCN1B-related DEE. Further research on the efficacy and safety of using newer ASMs, such as fenfluramine in patients under the age of 2 years is needed.
Fully Immersive Virtual Reality Game-Based Training for an Adolescent with Spastic Diplegic Cerebral Palsy: A Case Report
Authors: Lee Kyeongbong , Oh HyeJin , Lee GyuChang
Published: October 2022

Background: Recently, virtual reality-based training (VR-based training) is receiving attention as greater emphasis is placed on the importance of interest and motivation in participation. However, studies investigating the effects of fully immersive VR-based training are insufficient. Case presentation: We report a case of using a fully immersive VR game-based training in a patient with cerebral palsy. A 15-year-old girl was diagnosed with spastic diplegia cerebral palsy Gross Motor Function Classification System level II. A six-week intervention (18 sessions) phase was performed with one fully immersive VR game using PlayStation®VR in three sessions per week. After 18 sessions of training, the scores on the gross motor function measure-88 (Gross Motor Function Measure-88-GMFM-88), pediatric balance scale (PBS), timed up and go test (TUG), functional gait assessment (FGA), and 10 m walking test (10MWT) were improved: GMFM-88, 91.56 points (9.31 points increase); PBS, 45 points (6 points increase); TUG, 8.23 s (6.9 s decrease); FGA, 11 points (3 points increase); the 10 MWT, 5.27 s (6.59 s decrease). Conclusions: This study found that a fully immersive VR game-based training using PlayStation®VR may be an effective intervention for GMFCS level II adolescent, leading to some improvement of motor function, balance and gait skills in adolescents with cerebral palsy.
Maternal Risk Factors Associated with Preterm Births among Pregnant Women in Mogadishu, Somalia
Authors: Omar Abdifetah Ibrahim , Mohamed Amina Dahir , Farah Mohamed Garad , Mahad Ismail Abukar , Mohamed Suban Abdullahi , Dimbil Abyan Hassan , Mohamud Nadifo Salad , Abshir Fowziya Ahmed , Abdulkadir Umayma Abdinasir
Published: October 2022

Background: Premature birth impacts millions of newborns annually. Sixty percent of the world’s preterm births occur in Sub-Saharan Africa and South Asia. Somalia’s premature birth rates and maternal risk factors are poorly studied; hence, this study aims to identify maternal risk factors related to premature births in Mogadishu, Somalia. Methods: This unmatched case-control study was conducted at four maternity hospitals in Mogadishu, Somalia. The cases were newborns with gestational ages of less than 37 weeks; controls were newborns with gestational ages of 37 to 42 weeks. All were live singletons. Cross-tabulation and binary logistic regression were used to analyze the data; a p-value of 0.05 was deemed statistically significant. Result: Of the total of 499 newborns, 70 were cases, and 429 were controls. Adequate prenatal care, maternal urine analysis, tetanus toxoid (TT) vaccination, hemoglobin (Hb) measurement, ultrasound monitoring, intake of iron + folic acid (IFA) supplement, blood pressure (BP) measurement during the current pregnancy, as well as partograph usage during labor all significantly decreased risk of having premature births. A prior history of preterm delivery and preeclampsia, obstetric complications, and female genital mutilation (FGM) significantly increased the risk of preterm births. Conclusion: The utilization of antenatal care services, use of a partograph, obstetric complications, and prior history of premature birth and preeclampsia had a substantial effect on preterm birth rates. This study identifies female genital mutilation (FGM) as a previously unidentified risk factor for preterm birth that needs additional investigation.
Individual and Social Level Factors Influencing Repeated Pregnancy among Unmarried Adolescent Mothers in Katavi Region—Tanzania: A Qualitative Study
Authors: Mpimbi Salim Juma , Mmbaga Mwajuma , El-Khatib Ziad , Boltena Minyahil Tadesse , Tukay Samwel Marco
Published: October 2022

Adolescents’ pregnancy rates are still high in Tanzania, despite the efforts made by the national campaign. Within two years after the first pregnancy, adolescent mothers are more at risk of repeat conception. Repeated pregnancies are associated with increased maternal and perinatal outcomes. Katavi is a leading region in the country, with 45% adolescent pregnancy. Studies are scarce on factors influencing repeated pregnancy among unmarried adolescent mothers in the region. Therefore, this study explored the individual and social level factors influencing repeated pregnancy among unmarried adolescent mothers in the Katavi Region. An exploratory qualitative study, using key informant interviews (KIIs) was adopted for 16 participants. The study participants were unmarried adolescent mothers, aged 15–19 years, who were purposively sampled. Thematic analysis was used to analyze qualitative data. QSR Nvivo version 14 was used to analyze these data. The study established the individual factors influencing repeated pregnancy, which were inadequate sexuality knowledge, individually perceived barriers to contraceptive use, and the guarantee for marriage. Furthermore, the social factors identified were the power of decision-making, peer pressure, and the parent–child relationship. Inadequate education on sexuality is observed as a crucial factor influencing repeated pregnancy. Parents as primary educators should be encouraged to talk with their children, especially adolescent girls about sexual education.
Secondary Education and Class Stratification: Understanding the Hierarchy of Sexuality Education in a Chinese Vocational High School
Authors: Liu Chong
Published: October 2022

The discussion of sexuality education has a long history in China since the onset of modernisation in the early 20th century. Sexuality education has also existed in China’s educational system for a long time but in various forms. However, the discussions regarding students’ experiences and the influence of social stratification in China’s particular social context are still limited. From March to September 2019, the author visited an academic high school (pugao) and a vocational high school (zhigao) in Tianjin, China, to gain first-hand data to understand young people’s sexuality education experiences. In this paper, the author specifically paid attention to China’s social class, a rarely discussed topic in China’s society. She also tried to listen to the voices of young people and schoolteachers and help them to be heard. By presenting the insights from schoolteachers, students, as well as the materials from a nationally approved textbook, the author conducted a thematic analysis about how social class influences young people’s sexuality education experiences in secondary education in China.
Plain Radiographic Analysis of Laryngeal Dimensions in Young Children: Normal versus Croup
Authors: Kim Youngdae , Park Ji-Eun , Kim Jung-Heon
Published: October 2022

(1) Background: Contrary to a tenet of the funnel-shaped pediatric larynx with the cricoid level being narrowest, recent studies show the glottis and subglottis as the narrowest levels. To locate the functionally narrowest level of the larynx, we reported normal laryngeal dimensions and their croup-related changes in young children. (2) Methods: We reviewed normal plain neck radiographs recorded for the evaluation of minor trauma or foreign bodies in 504 children aged ≤4 years who visited the emergency department from 2016 through 2021. Using computed tomography-based localization of the glottis, we radiographically defined the subglottis and cricoid. At these levels, we measured diameters and calculated cross-sectional areas (CSAs) on the radiographs. The values were compared to the equivalent values of a 1:1 age-matched population with croup. (3) Results: In the study population (n = 401), the narrowest diameter and CSA were observed in the glottis. In detail, the mean anteroposterior/transverse diameters were 9.8/3.4 mm at the glottis, 8.5/5.6 mm at the subglottis, and 7.4/6.8 mm at the cricoid (p < 0.001), respectively. In the same order, the mean CSAs were 26.5, 38.1, and 40.5 mm2 (p < 0.001). All dimensions were narrower in the croup population (p < 0.001). We found croup-related narrowing, namely reductions in the transverse diameter and CSA that were more severe closer to the glottis (p < 0.001), without differences per level in the anteroposterior diameter. (4) Conclusions: This study confirms the glottis as the narrowest level of the larynx in young children. In addition, level-based differences in croup-related narrowing suggest some point between the glottis and subglottis as the functionally narrowest level.
Anti-Inflammatory Activity of Bilberry (Vaccinium myrtillus L.)
Authors: Sharma Anshul , Lee Hae-Jeung
Published: October 2022

Inflammation is important in the pathogenesis of several chronic diseases. The anti-inflammatory properties of berries have been investigated but the anti-inflammatory activity of bilberry has received little attention and a detailed review is yet to be published. Therefore, we compiled information on the phytochemicals of bilberry and preclinical and clinical studies of its anti-inflammatory properties. The review was based on studies from 2007 to date. Phytoconstituents of bilberries were phenolic acids, organic acids, anthocyanins, coumarins, flavonols, flavanols, tannins, terpenoids, and volatile chemicals. Data from cell and animal model studies show that bilberry has an anti-inflammatory effect by lowering tumor necrosis factor-α, interleukin (IL)-6, and IL-1β expression, inducing nitric oxide synthases and cyclooxygenases, and altering the nuclear factor kappa B and Janus kinase-signal transducer and activator of transcription signaling pathways. Bilberry supplementation as fruits (frozen, processed, and whole), juices, and anthocyanins reduced levels of inflammatory markers in most clinical studies of metabolic disorders. Therefore, bilberry may be useful for the prevention and treatment of chronic inflammatory disorders.
Influence of Antibiotics on Functionality and Viability of Liver Cells In Vitro
Authors: Doß Sandra , Blessing Corinne , Haller Katharina , Richter Georg , Sauer Martin
Published: October 2022

(1) Antibiotics are an important weapon in the fight against serious bacterial infections and are considered a common cause of drug-induced liver injury (DILI). The hepatotoxicity of many drugs, including antibiotics, is poorly analyzed in human in vitro models. (2) A standardized assay with a human hepatoma cell line was used to test the hepatotoxicity of various concentrations (Cmax, 5× Cmax, and 10× Cmax) of antibiotics. In an ICU, the most frequently prescribed antibiotics, ampicillin, cefepime, cefuroxime, levofloxacin, linezolid, meropenem, rifampicin, tigecycline, and vancomycin, were incubated with HepG2/C3A cells for 6 days. Cell viability (XTT assay, LDH release, and vitality), albumin synthesis, and cytochrome 1A2 activity were determined in cells. (3) In vitro, vancomycin, rifampicin, and tigecycline showed moderate hepatotoxic potential. The antibiotics ampicillin, cefepime, cefuroxime, levofloxacin, linezolid, and meropenem were associated with mild hepatotoxic reactions in test cells incubated with the testes Cmax concentration. Rifampicin and cefuroxime showed significantly negative effects on the viability of test cells. (4) Further in vitro studies and global pharmacovigilance reports should be conducted to reveal underlying mechanism of the hepatotoxic action of vancomycin, rifampicin, tigecycline, and cefuroxime, as well as the clinical relevance of these findings.
Water Security in South Asian Cities: A Review of Challenges and Opportunities
Authors: Sathre Roger , Antharam Sai Madhavi , Catena Michela
Published: October 2022

Achieving water security in South Asian cities will require a realistic and holistic understanding of the challenges that are growing in extent and severity. These challenges include the rapid rise in urban household water demand due to both overall population growth and increasing urbanization rate. Additionally, surface water supply in closed river basins is fully utilized, and there is little opportunity in these regions to increase the extraction of surface water to meet rising demands. Furthermore, groundwater extraction in most regions exceeds natural recharge rates, leading to rapidly falling annual water tables and seasonal depletion in hard rock regions and to gradually declining water tables requiring deeper wells and increased pumping effort in alluvial regions. Additionally, even in cities with abundant water resources, poorer segments of the population often face economic water scarcity and lack the means to access it. Nevertheless, there are important potential engineering opportunities for achieving water security in South Asian cities. Much withdrawn water is lost due to urban water distribution inefficiency, and a range of proven techniques exist to improve distribution. Metering of urban water can lead to structural improvements of management and billing, though the water needs of the poorest city residents must be ensured. Industrial water-use efficiency can be significantly improved in manufacturing and electricity generation. The quantities of wastewater generated in South Asia are large, thus treating and reusing this water for other purposes is a strong lever in enhancing local water security. There is limited potential for rooftop rainwater harvesting and storage, though capture-enhanced groundwater recharge can be important in some areas. Some individual inter-basin transfer projects may prove worthwhile, but very-large-scale projects are unlikely to contribute practically to urban water security. Overall, the water challenges facing South Asian cities are complex, and although no single intervention can definitively solve growing problems, numerous actions can be taken on many fronts to improve water security.
Corrosion Resistance of Mg/Al Vacuum Diffusion Layers
Authors: Zhang Shixue , Ding Yunlong , Zhuang Zhiguo , Ju Dongying
Published: October 2022

This study used a vacuum diffusion welding process to weld magnesium (Mg1) and aluminum (Al1060). The diffusion layers, with different phase compositions, were separated and extracted by grinding. The diffusion layers’ microstructures and phase compositions were analyzed using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Furthermore, the corrosion resistance of each diffusion layer and the substrates were investigated and compared by performing corrosion immersion tests and linear polarization measurements in a 3.5 wt.% NaCl solution. The results showed that diffusion layers consisting of Mg2Al3, Mg17Al12, and Mg17Al12/Mg-based solid solutions were formed at the interface of the Mg1/Al1060 vacuum diffusion joint. Furthermore, each diffusion layer’s structure and morphology were of good quality, and the surfaces were free from defects. This result was obtained for a welding temperature of 440 °C and a holding time of 180 min. The corrosion current density of Mg1 was 2.199 × 10−3 A/cm2, while that of the Al1060, Mg2Al3, Mg17Al12, and Mg17Al12/Mg-based solid solutions increased by order of magnitude, reaching 1.483 × 10−4 A/cm2, 1.419 × 10−4 A/cm2, 1.346 × 10−4 A/cm2, and 3.320 × 10−4 A/cm2, respectively. The order of corrosion rate was Mg1 > Mg17Al12 and Mg-based solid solution > Mg2Al3 > Mg17Al12 > Al1060. Moreover, all diffusion layers exhibited an improved corrosion resistance compared to Mg1. This was especially the situation for the Mg2Al3 layer and Mg17Al12 layer, whose corrosion resistances were comparable to that of Al1060.
Assessment of Defects under Insulation Using K-Medoids Clustering Algorithm-Based Microwave Nondestructive Testing
Authors: Tan Shin Yee , Akbar Muhammad Firdaus , Shrifan Nawaf H. M. M. , Nihad Jawad Ghassan , Ab Wahab Mohd Nadhir
Published: October 2022

Composite insulations, such as ceramics, are commonly utilized in the turbine system as a thermal coating barrier to protect the metal substrate against high temperatures and pressure. The presence of delamination in the composite insulations may cause turbine failure, leading to a catastrophic accident. Thus, regular non-destructive testing is required to detect and evaluate insulation defects. Among the non-destructive testing techniques, the microwave technique has emerged as a promising method for assessing defects in ceramic coatings. Although the method is promising, microwave non-destructive testing suffers from poor spatial imaging, making the defect assessment challenging. In this paper, a novel technique based on microwave non-destructive testing with a k-medoids clustering algorithm for delamination detection is proposed. The representative ceramic coating sample is scanned using a Q-band open-ended rectangular waveguide with 101 frequency points that operated between 33 to 50 GHz. The measured data is transformed from the frequency domain to the time domain using an inverse fast Fourier transform. The principal component analysis is then used to reduce the dimensionality of 101 time steps into only 3 dominant attributes. The attributes of each inspected location are classified as defect or defect-free using the k-medoids clustering algorithm for accurately detecting and sizing the defects in the ceramic insulation. The results reported in this paper highlight the superiority of the k-medoids clustering algorithm in delamination detection, with an accuracy rate of 95.4%. This is a significant step forward compared to earlier approaches for identifying ceramic defects.
Temperature Dependence of Electrical Resistance in Graphite Films Deposited on Glass and Low-Density Polyethylene by Spray Technology
Authors: Longo Angela , Di Bartolomeo Antonio , Faella Enver , Pelella Aniello , Giubileo Filippo , Sorrentino Andrea , Palomba Mariano , Carotenuto Gianfranco , Barucca Gianni , Tagliaferro Alberto , Coscia Ubaldo
Published: October 2022

Graphite lacquer was simply sprayed on glass and low-density polyethylene (LDPE) substrates to obtain large area films. Scanning Electron Microscopy (SEM) images, Raman spectra, X Ray Diffraction (XRD) spectra and current-voltage characteristics show that at room temperature, the as-deposited films on different substrates have similar morphological, structural and electrical properties. The morphological characterization reveals that the films are made of overlapped graphite platelets (GP), each composed of nanoplatelets with average sizes of a few tens of nanometers and about forty graphene layers. The thermoresistive properties of the GP films deposited on the different substrates and investigated in the temperature range from 20 to 120 °C show very different behaviors. For glass substrate, the resistance of the film decreases monotonically as a function of temperature by 7%; for LDPE substrate, the film resistance firstly increases more than one order of magnitude in the 20–100 °C range, then suddenly decreases to a temperature between 105 and 115 °C. These trends are related to the thermal expansion properties of the substrates and, for LDPE, also to the phase transitions occurring in the investigated temperature range, as evidenced by differential scanning calorimetry measurements.
Design and Research of Laminated Packaging Structure for Semiconductor Laser Diode
Authors: Xu Peidong , Wang Bin , Qian Yang , Wang Yong , Teng Yunjie , Wang Xiantao
Published: October 2022

The primary factor influencing semiconductor laser performance is photoelectric conversion efficiency. In this study, a heat sink structure in the form of a laminated DC-mount package was created using Solidworks 2018 in accordance with the semiconductor laser C-mount packaging structure specifications. The Workbench 17.0 program theoretically derived the link between the device’s junction temperature and power, and then optimized the size of its heat sink. The primary characteristics of semiconductor laser devices with various C-type and DC-type heat sink architectures were then packaged and compared. Results demonstrate that thermal resistance decreased by 31%, the power of the semiconductor laser device with a DC packaging structure increased by 0.5 W, and photoelectric conversion efficiency increased to over 60%, thereby lowering the temperature at the device junction and thermal resistance. at least to a certain point. the effect of the parasitic parameters of the package is effectively improved. Finally, the 3000 h life test confirmed this package construction’s stability.
Recent Advancements in Surface Modification, Characterization and Functionalization for Enhancing the Biocompatibility and Corrosion Resistance of Biomedical Implants
Authors: Thakur Abhinay , Kumar Ashish , Kaya Savaş , Marzouki Riadh , Zhang Fan , Guo Lei
Published: October 2022

Metallic materials are among the most crucial engineering materials widely utilized as biomaterials owing to their significant thermal conductivity, mechanical characteristics, and biocompatibility. Although these metallic biomedical implants, such as stainless steel, gold, silver, dental amalgams, Co-Cr, and Ti alloys, are generally used for bone tissue regeneration and repairing bodily tissue, the need for innovative technologies is required owing to the sensitivity of medical applications and to avoid any potential harmful reactions, thereby improving the implant to bone integration and prohibiting infection lea by corrosion and excessive stress. Taking this into consideration, several research and developments in biomaterial surface modification are geared toward resolving these issues in bone-related medical therapies/implants offering a substantial influence on cell adherence, increasing the longevity of the implant and rejuvenation along with the expansion in cell and molecular biology expertise. The primary objective of this review is to reaffirm the significance of surface modification of biomedical implants by enlightening numerous significant physical surface modifications, including ultrasonic nanocrystal surface modification, thermal spraying, ion implantation, glow discharge plasma, electrophoretic deposition, and physical vapor deposition. Furthermore, we also focused on the characteristics of some commonly used biomedical alloys, such as stainless steel, Co-Cr, and Ti alloys.
Effect of Microstructure on Mechanical Properties of 316 LN Austenitic Stainless Steel
Authors: Fang Kewei , Luo Kunjie , Wang Li
Published: October 2022

The microstructure development of 316 LN austenitic stainless steel (316 LNSS) during the aging process is investigated in this article. The thermal aging processes were conducted at 750 °C with different periods ranging from 50 to 500 h. The metallographic results show that the coherent and incoherent twins were present in the original 316 LNSS grains, but dwindled as the aging period increased. After 50 h of aging, many fine, dispersed particles precipitated from the matrix, which were identified as M23C6 by energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM). Additionally, the impact toughness and Brinell hardness (HBW) changed during the aging, which was closely related to the effects of dispersion strengthening and solution strengthening. A negatively linear relationship between Brinell hardness and Charpy impact energy was established, which could be utilized to predict the degree of thermal embrittlement.
Research on Dynamic Stress–Strain Change Rules of Rubber-Particle-Mixed Sand
Authors: Zhang Yunkai , Liu Fei , Bao Yuhan , Yuan Haiyan
Published: October 2022

We conducted GDS dynamic triaxial tests to study the change rules of the hysteresis curve morphology, axial strain, dynamic elastic modulus, and damping ratio of waste tire rubber-mixed sand-based subgrade model samples with different rubber particle sizes, rubber mixing amounts, and loading times. The research revealed the developmental rule of the hysteresis curves of waste tire rubber-mixed-sand samples under cyclic loading. From the analyses and comparison of the dynamic stress–strain change rules of rubber-particle-mixed-sand samples under different test conditions, it was concluded that the dynamic elastic modulus and shear stiffness of rubber-mixed-sand samples were smaller than those of pure sand samples under cyclic loading while their damping ratios were greater than that of pure sand samples, promoting vibration resistance and reduction to a larger extent. Therefore, this conclusion is of guiding significance for engineering practice.
Bi-Substituted Ferrite Garnet Type Magneto-Optic Materials Studied at ESRI Nano-Fabrication Laboratories, ECU, Australia
Authors: Nur-E-Alam Mohammad , Vasiliev Mikhail , Alameh Kamal
Published: October 2022

Since 2007, at the Electron Science Research Institute (ESRI) nano-fabrication laboratories, Edith Cowan University, Australia, we have devoted research efforts to the synthesis and characterization of bismuth-containing ferrite-garnet-type thin-film magneto-optic (MO) materials of different compositions. We report on the growth and characteristics of radio frequency (RF) magnetron sputtered bismuth-substituted iron-garnet thin films. We study the process parameters associated with the RF magnetron sputter deposition technique and investigate the results of optimizing process parameters. To achieve the best MO properties, we employ a few unique techniques, such as co-sputtered nanocomposite films and all-garnet multilayer structures, as well as the application of oxygen plasma treatment to amorphous garnet layers immediately following the deposition process. We demonstrated a remarkable enhancement in the MO properties of Bi-containing ferrite-type garnet thin-film materials, including record-high MO figures of merit and improved conventional and unconventional hysteresis loops of Faraday rotation. Previously unpublished research results on the forward-looking applications of magnetic garnet coatings applied to microparticles of advanced luminescent materials are reported. In the context of developing the next-generation ultra-fast optoelectronic devices, such as light intensity switches and modulators, high-speed flat panel displays, and high-sensitivity sensors, it is important to consider the desirable optical, magnetic, and magneto-optic properties that are found in highly bismuth-substituted iron garnet thin-film materials of various composition types.
Experimental Research on Dynamic Response of Layered Medium under Impact Load
Authors: Liu Mingqing , Gan Qinyu
Published: October 2022

Stress waves propagating through multiple parallel fractures are attenuated due to the multiple wave reflections and transmissions at the fractures. The dynamic response of a layered medium under an impact load is systematically studied by a model test in this paper. The effects of the impact energy, number of joints, thickness of the medium and joint layer, material properties of the cementation layer, and other factors of the dynamic stress propagation and attenuation of layered media are analyzed. Studies have shown that Sadovsky’s empirical formula fits the attenuation law of vertical peak velocity well, and the obtained attenuation coefficient k and index b can be used for reflecting the dynamic response characteristics of layered media. The attenuation coefficient k is positively correlated with the impact height and negatively correlated with the plate thickness in a single-layer plate impact test. The thickness of the medium layer is the main factor affecting the vibration response of the layered medium in the impact test of the multi-layer slab. The medium thickness, the number of medium layers, and the number of joints have little influence. The different cementation materials and the change of cementation thickness will have a great influence on the dynamic response of layered media, when the cementation layer is filled with joint surfaces for the impact test of multi-layer plates.
Corrosion Fatigue Test and Performance Evaluation of High-Strength Steel Wires Based on the Suspender of a 11-Year-Old Concrete-Filled Steel Tube Arch Bridge
Authors: Deng Yulin , Deng Luming
Published: October 2022

In this study, based on an actual project, the steel wire in the suspender of a concrete-filled steel tube arch bridge was selected from appropriate samples to perform acetic acid-accelerated salt spray tests, and steel wire samples with different corrosion degrees were obtained. A laser microscope was used to measure the roughness of the samples, and three corrosion samples were randomly selected from each group for grinding. Fatigue tests were performed on steel wire samples with different degrees of corrosion and polished steel wire samples, and the fatigue fracture was observed and analyzed. The results showed that few cracks on the steel wire surface could be eliminated by grinding, and the fatigue life of the specimens could be increased. Finally, the stress-life-mass loss rate (S-N-η) probability model based on the Weibull distribution was obtained using the measured fatigue data, which can be further referenced in the planning of the inspection of suspender service status, steel wire corrosion protection, and fatigue life prediction, etc.
Change in Dimensions and Surface Roughness of 42CrMo4 Steel after Nitridation in Plasma and Gas
Authors: Dobrocky David , Pokorny Zdenek , Joska Zdenek , Sedlak Josef , Zouhar Jan , Majerik Jozef , Studeny Zbynek , Prochazka Jiri , Barenyi Igor
Published: October 2022

The influence of plasma nitriding and gas nitriding processes on the change of surface roughness and dimensional accuracy of 42CrMo4 steel was investigated in this paper. Both processes almost always led to changes in the surface texture. After plasma nitriding, clusters of nitride ions were formed on the surface of steel, while gas nitriding very often led to the new creation of a formation of a “plate-like” surface texture. In both cases of these processes, a compound layer in specific thickness was formed, although the parameters of the processes were chosen with the aim of suppressing it. After the optimizing of nitriding parameters during nitriding processes, it was found that there were no changes in the surface roughness evaluated using the Ra parameter. However, it turned out that when using a multi-parameter evaluation of roughness (the parameters Rz, Rsk and Rku were used), there were presented some changes in roughness due to nitriding processes, which affect the functional behavior of the components. Roughness changes were also detected by evaluating surface roughness profiles, where nitriding led to changes in peak heights and valley depths. Nitriding processes further led to changes in dimensions in the form of an increase of 0.032 mm on average. However, the magnitude of the change has some context on chemical composition of material. A larger increase in dimensions was found with gas nitriding. The change in the degree of IT accuracy is closely related to the change in dimension. For both processes, there was a change of one degree of IT accuracy compared to the ground part (from IT8 to IT9). On the basis of the achieved dimensional accuracy results, a coefficient of change in the degree of accuracy IT was created, which can be used to predict changes in the dimensional accuracy of ground surfaces after nitriding processes in degrees of accuracy IT3–IT10. In this study, a tool for predicting changes in degrees of accuracy of ground parts after nitriding processes is presented.
Study on Vibration Compaction Energy of Basement Material
Authors: Zhou Hao , Guo Yongjian , Xu Qiang , Zhang Guixia , Wang Zhen
Published: October 2022

In order to confirm the vibrate compaction energy, the indoor vibration compaction was conducted. Indoor vibration compactor was used to compact skeleton dense cement stabilized aggregate. The acceleration and displacement of the indenter and compaction pressure during the compaction process were measured. The bounce model and the hysteresis curve based on measurement parameters were used to calculate the compaction energy. Three vibration compaction energy were affirmed as: energy of the machinery itself (Eself), energy transmitted from machinery to compacted material (Et) and energy stored by compacted materials (Es). The energy Eself was about 40 J (joule). During each compaction process, energy Et was only 1–1.8 J. In a one-minute compaction process, 2500 J of energy would be transmitted, but only 38 J could be stored by the compacted material.
Microstructure and Mechanical Properties of GH4169 Superalloy and Si3N4 Ceramic Joints Brazed with AgCuTi/Cu foam/AgCuTi Composited Filler
Authors: Yang Xiaohong , Xue Yang , Wang Shenggang , Ge Jianya , Chen Yuan , Zhang Zhengzhong , Tang Jinhua , Xiao Junjian
Published: October 2022

GH4169 superalloy and Si3N4 ceramics were vacuum-brazed with AgCuTi+Cu foam composite filler. The effect of brazing temperature on the microstructure and mechanical properties of the GH4169/Si3N4 joint was studied. The results show that the interface microstructure of the GH4169/Si3N4 joint is the GH4169 superalloy/TiCu+Ti2Ni+TiCu2+Ag(s, s)+TiCu4+Cu(s, s)+TiN+Ti5Si3/Si3N4 ceramics. With the increase in brazing temperature, the element diffusion between the base metal and the brazing filler intensifies, and the interfacial reaction layer thickens, which is conducive to the improvement of shear strength. At 850 °C, the maximum shear strength of the joint is 196.85 MPa. After further increases in the brazing temperature, Cu foam dissolves completely, and the Ti-Cu intermetallic compounds increase, which is harmful to the shear strength due to the increases in the brittle phase. However, when the brazing temperature reaches 910 °C, the shear strength of the brazing joint slightly increases under the combined effect of the Ti-Cu intermetallic compounds and the thickness of the reaction layer.
Effect of KCl Addition on First Hydrogenation Kinetics of TiFe
Authors: Manna Joydev , Huot Jacques
Published: October 2022

In this paper, the effect of the addition of potassium chloride (KCl) by ball milling on the first hydrogenation kinetics of TiFe is reported. After milling, KCl was uniformly distributed on the TiFe’s surface. As-synthesized TiFe does not absorb hydrogen. However, after ball milling with KCl, it absorbed 1.5 wt.% of hydrogen on the first hydrogenation without any thermal treatment. The storage capacity of TiFe with KCl addition is higher than that of the ball milled pure TiFe. The effects of the amount of KCl additive in TiFe and ball milling time on first hydrogenation kinetics are reported. It is noted that, with an increase in KCl amount and ball milling time, hydrogenation kinetics are improved. However, hydrogen storage capacity decreased for both cases.
Fruticose Lichen Communities at the Edge: Distribution and Diversity in a Desert Sky Island on the Colorado Plateau
Authors: Robison Abigail , Baugh Mikele , Muggia Lucia , Leavitt Steven D.
Published: October 2022

Subalpine habitats in sky islands in the Southwestern USA are currently facing large-scale transformations. Lichens have widely been used as bioindicators of environmental change. On the Colorado Plateau, fruticose lichens occur in patchy, disconnected populations, including unique lichen-draped conifer sites in subalpine forests in the La Sal Mountains in southeastern Utah. Here, we document the distribution and fungal diversity within these lichen communities. We find that lichen-draped conifer sites in the La Sal Mountains are restricted to only three known, small areas in Picea englemannii forests above 3000 m above sea level, two of which have recently been impacted by wildfire. We document 30 different species of lichen-forming fungi in these communities, several which represent the first reports from the Colorado Plateau. We also characterize mycobiont haplotype diversity for the fruticose lichens Evernia divaricata, Ramalina sinensis, and multiple Usnea species. We also report a range of diverse fungi associated with these lichens, including genetic clusters representing 22 orders spanning seven classes of Ascomycetes and fewer clusters representing Basidiomycetes. Our results provide a baseline for ongoing monitoring and help to raise awareness of unique lichen communities and other biodiversity in the region.