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Effect of discontinuous glass fibers on mechanical properties of glass ionomer cement
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This study
investigated the reinforcing effect of discontinuous glass microfibers with various
loading fractions on selected mechanical properties of self-cure glass ionomer
cement (GIC). Experimental fiber reinforced GIC (Exp-GIC) was prepared by
adding discontinuous glass microfiber (silane/non-silane treated) of 200-300 µm
in length to the powder of self-cure GIC (GC Fuji IX) with various mass ratios
(15,20,25,35, and 45 mass%) using a high speed mixing device. Flexural
strength, flexural modulus, work of fracture, compressive strength and
diametral tensile strength were determined for each experimental and control materials.
The specimens (n=8) were wet stored (37 °C for one day) before testing. Scanning electron microscopy equipped with energy
dispersive spectrometer was used to analysis the surface of silanized or
non-silanized fibers after treated with cement liquid. The results were analysed
with using multivariate analysis of variance MANOVA. Fiber-reinforced GIC (25 mass%) had significantly higher mechanical
performance of flexural modulus (3.8 GPa), flexural strength (48 MPa), and
diametral tensile strength (18 MPa) (p<0.05) compared to unreinforced
material (0.9 GPa, 26 MPa and 8 MPa). No statistical significant
difference in tested mechanical properties was recorded between silanized and non-silanized Exp-GIC groups. Compressive strength did not show any significant differences (p>0.05)
between the fiber-reinforced and unreinforced GIC. The use of discontinuous glass microfibers
with self-cure GIC matrix considerably increased the all of the studied properties
except compressive strength.
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Normal neonatal brainstem audiometry in preterm infants predicted normal hearing later in childhood
Get PDFViral acute respiratory infections in neonatal intensive care healthcare workers: a nine-month point-prevalence cohort study
Get PDFBackground: Healthcare-acquired viral acute respiratory infections (ARIs) are a common problem in neonatal care. Health-care workers may transmit viruses to neonates when having a symptomatic or asymptomatic ARI.Aim: This prospective nine-month repeated point-prevalence cohort study aimed to investigate the occurrence and aetiology of asymptomatic and symptomatic ARIs in health-care employees in a tertiary neonatal intensive care unit (NICU).Methods: Flocked nasal swabs were collected on every second Tuesday in a NICU from all personnel working on that day. Additionally, in the case of ARI symptoms, a nasal swab was self-collected by the study subjects.Findings: A virus was detected in 16 (3.3%) of the asymptomatic subjects. Altogether 36 symptomatic ARIs (mean 0.5 per person) were reported.Conclusion: Our data suggests that ARIs are not uncommon among NICU health-care workers and moreover are commonly asymptomatic. It is noteworthy that these individuals may transmit.</p
The use of event-related potentials in the investigation of cognitive performance in people with Multiple Sclerosis : Systematic review
Get PDFA biomarker of cognition in Multiple Sclerosis (MS) that is independent from the response of people with MS (PwMS) to test questions would provide a more holistic assessment of cognitive decline. One suggested method involves event-related potentials (ERPs). This systematic review tried to answer five questions about the use of ERPs in distinguishing PwMS from controls: which stimulus modality, which experimental paradigm, which electrodes, and which ERP components are most discriminatory, and whether amplitude or latency is a better measure. Our results show larger pooled effect sizes for visual stimuli than auditory stimuli, and larger pooled effect sizes for latency measurements than amplitude measurements. We observed great heterogeneity in methods and suggest that future research would benefit from more uniformity in methods and that results should be reported for the individual subtypes of PwMS. With more standardised methods, ERPs have the potential to be developed into a clinical tool in MS
aMMP-8 and MMP-9: Potential Biomarkers for periodontitis Progression in Patients Receiving Radiotherapy for Head and Neck Carcinoma
Get PDFIntroductionMatrix metalloproteinases (MMP)-8 and −9 are regarded as biomarkers for periodontitis. The impact of head and neck carcinoma (HNC) radiotherapy (RT) on these biomarkers remains largely unexplored. This study aims to evaluate the impact of HNC RT on the proteases from host and bacteria, and their associations with the progression of periodontitis.MethodsTwenty-one patients with HNC receiving RT were included in this study. Mouthrinse samples were collected before RT (T0) and at the end of RT (T1). Periodontal examinations were conducted at T0 and one month after RT (T2). Samples were analyzed using a point-of-care kit for active (a) MMP-8, and ELISA for total (t) MMP-8, MMP-9, and interleukin (IL)-6 levels. Molecular forms of MMP-9 were assessed by gelatinolytic zymography. The activity levels of bacterial proteases, gingipain from Porphyromonas gingivalis and dentilisin from Treponema denticola, were assayed by using Fluorescence Resonance Energy Transfer (FRET) peptide substrates. Modified cumulative risk score (CRS) index was used for combinatory biomarker analysis. We evaluated the impact of RT on biomarker concentrations as well as their associations with the mean clinical attachment loss (CAL) development, categorized as either progressive (CAL ≥0.1 mm) or low/no progression (CAL ResultsAll patients suffered from periodontitis. There were significant increases in the levels of aMMP-8, tMMP-8, aMMP-9, as well as in four modified CRS-indices due to RT (P P = 0.365) or dentilisin (P = 0.620). The mean levels of aMMP-8 and tMMP-9 were associated with CAL progression (P = 0.044, P = 0.029, respectively).ConclusionHNC RT may result in the progression of periodontitis by increased activities of MMP-8 and -9. It seems that HNC RT has little impact on the activities of the bacteria-derived proteases dentilisin and gingipain.</p
Entering the Classroom : Do Newcomers Experience More Peer Victimization than Their Established Peers?
Get PDFStudents changing classrooms or schools may face challenges from entering a new peer context without friends and standing out from the crowd as newcomers. Two studies examined whether newcomer status predicts peer victimization at school, exploring several potential moderating factors (e.g., social anxiety, immigrant background and having good friends in the classroom) (Study 1: n = 6,199; Mage=12.53) and whether being victimized as a newcomer varied based on the different reasons for mobility (e.g., parental dissolution, residential move, previous victimization, changing into a more suitable school) (Study 2: n = 58,738). In both studies, newcomers reported higher peer victimization compared to established students. Having good friends in the classroom was found as a protective factor in Study 1, being the only statistically significant moderator. All reasons for mobility, except changing into a more suitable school, predicted slightly higher peer victimization in Study 2, with the highest risk for those changing schools due to previous peer victimization experiences
Neonatal brain dynamic functional connectivity in term and preterm infants and its association with early childhood neurodevelopment
Get PDFBrain dynamic functional connectivity characterises transient connections between brain regions. Features of brain dynamics have been linked to emotion and cognition in adult individuals, and atypical patterns have been associated with neurodevelopmental conditions such as autism. Although reliable functional brain networks have been consistently identified in neonates, little is known about the early development of dynamic functional connectivity. In this study we characterise dynamic functional connectivity with functional magnetic resonance imaging (fMRI) in the first few weeks of postnatal life in term-born (n = 324) and preterm-born (n = 66) individuals. We show that a dynamic landscape of brain connectivity is already established by the time of birth in the human brain, characterised by six transient states of neonatal functional connectivity with changing dynamics through the neonatal period. The pattern of dynamic connectivity is atypical in preterm-born infants, and associated with atypical social, sensory, and repetitive behaviours measured by the Quantitative Checklist for Autism in Toddlers (Q-CHAT) scores at 18 months of age. © The Author(s) 2024
Sustainable International Business: Smart Strategies for Business and Society
No full textInternational business today is increasingly stimulated to be conducted in a socially and environmentally responsible way. The United Nations’ Sustainable Development Goals have emphasized the role of international business as an agent of transformation. Sustainability and related issues are global by nature; thus, they have a reach in international business and in providing international entrepreneurial opportunities. Despite this, research on international business and sustainable development has focused primarily on large multinational enterprises, while studies on international entrepreneurship (IE) have remained relatively absent. This study contributes to the literature on the internationalization of small and medium-sized enterprises (SMEs) by shedding light on how managers of international enterprises make sense of responsible business practices (RBPs). With an empirical sample of 179 Finnish internationalized SMEs and linear regression analysis, the study finds out that communication of sensemaking enhances the firms’ RBPs. This study illustrates the role of the sensemaking approach in IE, where it is essential to account for managerial sensemaking when seeking to explain how international entrepreneurial firms strategize for sustainable international business and can potentially contribute to Sustainable Development Goals.</p
Unsiloed agroforestry research and policy: Livelihood and multifunction as chestnut (Castanea sativa) management priorities for Türkiye
Get PDFIn this study, we investigate variation in the priorities for the chestnut tree held by stakeholders across T & uuml;rkiye in order to highlight the importance of unsiloed research and policy in the study area and beyond. We designed our study to evaluate the operating hypothesis of state agencies who manage the tree in sharp regional contrast, with the western provinces managed overwhelmingly for horticulture, and the northern provinces for silviculture. We utilized ethnobiological methodologies of plant trait preference cataloguing and freelisting to engage and analyze the priorities for chestnut trees for 96 stakeholder households across T & uuml;rkiye 's chestnut suitable territory. We found that no household utilized the tree for one purpose only, that every household used the tree for both its fruits and its timber, and that the vast majority utilized the tree for nuts, timber and one other category of use. We explored the resulting data using saliency analysis, multiple correspondence analysis and geospatial visualization through inverse distance weighting. We found no significant effect of western or northern location on priorities. Our findings substantiate conservation and livelihood development theories which advocate for unsiloed, interdisciplinary research informed by stakeholders, and also showcase an application of agroforestry as a framework for directly amplifying the priorities of livelihood practitioners in the formulation of land use policy. Insights generated by this study support recommendations for T & uuml;rkiye and beyond, including more thoroughly interdisciplinary research to perpetuate multifunctional use of trees as well as more regional and unified governmental strategies for conservation and rural livelihood viability.</p
Learning Analytics Methods and Tutorials A Practical Guide Using R
No full textSequence analysis is a data mining technique that is increasingly gaining ground in learning analytics. Sequence analysis enables researchers to extract meaningful insights from sequential data, i.e., to summarize the sequential patterns of learning data and classify those patterns into homogeneous groups. In this chapter, readers will become familiar with sequence analysis techniques and tools through real-life step-by-step examples of sequential trace log data of students’ online activities. Readers will be guided on how to visualize the common sequence plots and interpret such visualizations. An essential part of sequence analysis is the discovery of patterns within sequences through clustering techniques. Therefore, this chapter will demonstrate the various sequence clustering methods, calculator of cluster indices, and evaluation of clustering results.</p