208 research outputs found

    Using Orthogonal Locality Preserving Projections to Find Dominant Features for Classifying Retinal Blood Vessels

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    Automatically classifying retinal blood vessels appearing in fundus camera imaging into arterioles and venules can be problematic due to variations between people as well as in image quality, contrast and brightness. Using the most dominant features for retinal vessel types in each image rather than predefining the set of characteristic features prior to classification may achieve better performance. In this paper, we present a novel approach to classifying retinal vessels extracted from fundus camera images which combines an Orthogonal Locality Preserving Projections for feature extraction and a Gaussian Mixture Model with Expectation-Maximization unsupervised classifier. The classification rate with 47 features (the largest dimension tested) using OLPP on our own ORCADES dataset and the publicly available DRIVE dataset was 90.56% and 86.7% respectively

    Geographical distribution of freshwater fishes in Saudi Arabia

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    Species presence/absence data in different water bodies in different regions of Saudi Arabia were collated from the literature and collected from field surveys to determine the geographical distribution of fish species in the country. Freshwater fish are mainly located in drainages in the south-west of the Kingdom of Saudi Arabia, both in the lowlands (western drainage systems) and highlands (eastern drainage systems) of the Sarawat Mountain Range. The eastern drainage systems were dominated by three endemic species, while the western drainage systems had a variety of endemic and non-native species. Ten non-native fish species were reported, mainly in artificial water bodies in the north and east of the country, but also in dams located in Al Baha Region, Abha and Rabigh, meaning both western and eastern drainage systems are being colonised by non-native species such as Oreochromis and Carassius species

    Single Nucleotide Polymorphisms in HIF-1A, VEGFa, and VHL Genes: A Comparative Study between Sea Level and High-Altitude Residents in West Saudi Arabia

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    Background: This comprehensive molecular study investigates the genetic variations in individuals residing at different altitudes in West Saudi Arabia, specifically contrasting sea-level residents in Jeddah (SL) with high-altitude dwellers in Taif (HA). The study focuses on the significant role of genetic adaptations in response to environmental challenges, particularly hypoxia. Understanding these genetic differences according to geographical location is crucial for multiple reasons. It not only sheds light on the adaptive mechanisms that humans develop in response to environmental stressors like reduced oxygen levels but also has broader implications for medical, anthropological, and evolutionary studies. By exploring how distinct populations adapt to their environments, this research provides valuable insights into the complex interplay between genetics, health, and disease, highlighting the importance of considering genetic diversity in medical and genetic research.Methods: The research involved amplifying and sequencing three pivotal genes associated with hypoxia adaptation: Hif-1a, VEGFa, and VHL. Advanced genomic techniques were utilized to analyze samples from 22 volunteers, 10 from the sea level region of Jeddah and 12 from the high-altitude region of Taif. The study aimed to identify and analyze single nucleotide polymorphisms (SNPs) in these genes and their implications in altitude adaptation.Results: Distinct SNPs were identified in the Hif-1a, VEGFa, and VHL genes, with high-altitude residents displaying more pronounced variations. The phylogenetic analysis demonstrated clear genetic clustering based on altitude, highlighting the molecular adaptations induced by altitude variations. The study reveals a complex interplay between genetics and environmental conditions, significantly contributing to our understanding of human adaptation to high altitudes.Conclusion: This research underscores the profound impact of altitude on human genetics. The findings provide critical insights into how genetic variations facilitate adaptation to challenging environmental conditions, such as hypoxia, encountered at high altitudes. These insights have broad implications, potentially informing medical research related to altitude sickness and other altitude-related health issues.Keywords: High-Altitude Adaptation; Single Nucleotide Polymorphisms (SNPs); Hif-1a Gene; VEGFa Gene; VHL Gene; Phylogenetic Analysis; Saudi Arabian Populations 

    Unmodified Titanium Dioxide Nanoparticles as a potential contrast agent in photon emission computed tomography

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    Highly crystalline titanium dioxide nanoparticles (TiO2 -NPs) are synthesized via a simple hydrothermal technique. After structural and compositional analysis, the as-synthesized unmodified TiO2 -NPs are tested for improvement in two modes of kilovoltage radiation therapy and singlephoton emission computed tomography (SPECT)/computed tomography (CT). Our results show that the unmodified TiO2 -NPs provide an observable enhancement in CT scan image contrast ranging from 0 ± 3 HU (without NPs) to 283.7 ± 3 HU (0.23 g/mL). TiO2 -NPs has excellent biocompatibility, selective uptake at target sites, and reduced toxicity. The unmodified TiO2 -NPs as a contrast agent can significantly improve the existing methods of diagnosing and treating cancer

    Impact of pericardial adhesions on diastolic function as assessed by vortex formation time, a parameter of transmitral flow efficiency

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    <p>Abstract</p> <p>Background</p> <p>Pericardial adhesions are a pathophysiological marker of constrictive pericarditis (CP), which impairs cardiac filling by limiting the total cardiac volume compliance and diastolic filling function. We studied diastolic transmitral flow efficiency as a new parameter of filling function in a pericardial adhesion animal model. We hypothesized that vortex formation time (VFT), an index of optimal efficient diastolic transmitral flow, is altered by patchy pericardial-epicardial adhesions.</p> <p>Methods</p> <p>In 8 open-chest pigs, the heart was exposed while preserving the pericardium. We experimentally simulated early pericardial constriction and patchy adhesions by instilling instant glue into the pericardial space and using pericardial-epicardial stitches. We studied left ventricular (LV) function and characterized intraventricular blood flow with conventional and Doppler echocardiography at baseline and following the experimental intervention.</p> <p>Results</p> <p>Significant decreases in end-diastolic volume, ejection fraction, stroke volume, and late diastolic filling velocity reflected the effects of the pericardial adhesions. The mean VFT value decreased from 3.61 ± 0.47 to 2.26 ± 0.45 (P = 0.0002). Hemodynamic variables indicated the inhibiting effect of pericardial adhesion on both contraction (decrease in systolic blood pressure and +dP/dt decreased) and relaxation (decrease in the magnitude of -dP/dt and prolongation of Tau) function.</p> <p>Conclusion</p> <p>Patchy pericardial adhesions not only negatively impact LV mechanical functioning but the decrease of VFT from normal to suboptimal value suggests impairment of transmitral flow efficiency.</p

    Structural, optical, and antibacterial efficacy of pure and zinc-doped copper oxide against Pathogenic bacteria

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    Copper oxide and Zinc (Zn)-doped Copper oxide nanostructures (CuO-NSs) are successfully synthesized by using a hydrothermal technique. The as-obtained pure and Zn-doped CuONSs were tested to study the effect of doping in CuO on structural, optical, and antibacterial properties. The band gap of the nanostructures is calculated by using the Tauc plot. Our results have shown that the band gap of CuO reduces with the addition of Zinc. Optimization of processing conditions and concentration of precursors leads to the formation of pine needles and sea urchinlike nanostructures. The antibacterial properties of obtained Zn-doped CuO-NSs are observed against Gram-negative (Pseudomonas aeruginosa, Klebsiella pneumonia, Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria via the agar well diffusion method. Zn doped s are found to have more effective bacterial resistance than pure CuO. The improved antibacterial activity is attributed to the reactive oxygen species (ROS) generation

    Patterns and Characteristics of Children with Developmental Dysplasia of the Hip Treated in Saudi Arabia: Data from the National Saudi Program for Developmental Dysplasia of the Hip

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    The National Hip Dysplasia Program (NHDP) was launched in December 2016 to treat children with developmental dysplasia of the hip (DDH) in Saudi Arabia; however, its outcomes have not been examined or published yet. Therefore, our aim in this study was to report the findings of this unique program. In this retrospective study design, we included data of patients with DDH who received interventions provided by the NHDP, from two major Saudi regions (Northern Borders and Al-Jouf regions), from April 2017 to February 2021. Outcomes reported included age at first surgery, sex, involved side, interventions provided, and recurrence rates for failed surgeries. Independent t -tests compared age differences between Northern Borders region and Al-Jouf region, whereas chi-square tests determined the differences between Northern Borders region and Al-Jouf region regarding sex and the involved side of DDH distributions. Out of 404 children with DDH, 300 (82.3% were females and 17.7% were males) were included and were first seen at the age of 20 months in the Northern Borders region and at the age of 22 months in Al-Jouf region. We found a significant difference in the number of bilateral DDH cases between the Northern Borders ( n = 129; 70.1%) and Al-Jouf ( n = 59; 51.0%) ( P = 0.003) regions. In the Northern Borders region, the majority of children with unilateral DDH were treated by open reduction (right side = 40.7%; left side = 60.7%), with recurrence rates of 14.8% for the right side and 7.1% for left side. In the Al-Jouf region, the majority of children with unilateral DDH were treated by femoral shortening with graft (right side = 69.2%; left side = 54.9%), with a recurrence rate of 7.7% for the right-sided DDH. More than half of the children with bilateral DDH underwent operations for both sides (Northern Borders region = 62.0%; Al-Jouf region = 57.9%). The study provides a detailed analysis of DDH among children in the Northern Borders and Al-Jouf regions, highlighting significant regional differences in both the prevalence and treatment outcomes. Future studies need to develop strategies to prevent and minimize potential long-term effects of DDH

    TinderBook: Fall in love with culture

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    More than 2 millions of new books are published every year and choosing a good book among the huge amount of available options can be a challenging endeavor. Recommender systems help in choosing books by providing personalized suggestions based on the user reading history. However, most book recommender systems are based on collaborative filtering, involving a long onboarding process that requires to rate many books before providing good recommendations. Tinderbook provides book recommendations, given a single book that the user likes, through a card-based playful user interface that does not require an account creation. Tinderbook is strongly rooted in semantic technologies, using the DBpedia knowledge graph to enrich book descriptions and extending a hybrid state-of-the-art knowledge graph embeddings algorithm to derive an item relatedness measure for cold start recommendations. Tinderbook is publicly available (http://www.tinderbook.it) and has already generated interest in the public, involving passionate readers, students, librarians, and researchers. The online evaluation shows that Tinderbook achieves almost 50% of precision of the recommendations

    Social media marketing strategy: definition, conceptualization, taxonomy, validation, and future agenda

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    Although social media use is gaining increasing importance as a component of firms’ portfolio of strategies, scant research has systematically consolidated and extended knowledge on social media marketing strategies (SMMSs). To fill this research gap, we first define SMMS, using social media and marketing strategy dimensions. This is followed by a conceptualization of the developmental process of SMMSs, which comprises four major components, namely drivers, inputs, throughputs, and outputs. Next, we propose a taxonomy that classifies SMMSs into four types according to their strategic maturity level: social commerce strategy, social content strategy, social monitoring strategy, and social CRM strategy. We subsequently validate this taxonomy of SMMSs using information derived from prior empirical studies, as well with data collected from in-depth interviews and a quantitive survey among social media marketing managers. Finally, we suggest fruitful directions for future research based on input received from scholars specializing in the field
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