Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
82,809
result(s) for
"Raj, A"
Sort by:
Adjusting for truncated study duration in recurrent event analysis: A weighting approach for clinical trials
In recurrent event analysis with fixed follow-up intervals, truncated follow-up due to early dropout or study termination introduces bias and reduces precision in risk estimates, particularly in clinical trials where shorter observation periods may underestimate event risks.
We propose a time-based weighting approach using the ratio of observed-to-expected follow-up duration in the Prentice-Williams-Peterson Gap Time (PWP-GT) model. The method was evaluated in simulations and applied to a double-blinded trial (N = 4000) comparing 500 mg vs. 1500 mg daily calcium supplementation for preeclampsia prevention. For demonstration of the problem and application of the weighting method, drug non-adherence at follow-up visits was considered as the recurrent event.
Simulations showed the weighted PWP-GT model had lower bias (1.0% vs. 1.3%) and improved precision compared to the unweighted model, with coverage probabilities >94%. In the trial data, weighting yielded smaller standard errors and a more conservative hazard ratio for hypertension family history (weighted HR = 1.14, SE = 0.054 vs. unweighted HR = 1.23, SE = 0.065).
Unaccounted truncated follow-up in recurrent event studies can bias the risk estimation if unaccounted for. Our findings demonstrate that total time-based weighting effectively addresses this bias and enhances precision in both simulated and real datasets.
Journal Article
تاريخ العالم في سبعة أشياء رخيصة : دليل الرأسمالية، والطبيعة، ومستقبل الكوكب
حقق هذا الكتاب منذ صدوره ضجة كبرى في الأوساط الأكاديمية والثقافية، إذ تناول فكرة الرأسمالية من زوايا مختلفة قطعت مع القراءات الأكاديمية المغلقة. يربط الكتاب فكرة الرأسمالية بالطبيعة ويرى المؤلفان أن استغلال الطبيعة على نحو خاطئ ومتوحش مهد المجال لاستغلال البشر وبذلك نشأت الرأسمالية على ثنائية استغلال الطبيعة والإنسان، وهو استغلال جعل من العالم عالما رخيصا ففكرة الاستعمار هي التي جعلت من المال رخيصا بما أنها استطاعت توفيره من جماجم المضطهدين كما جعلت من الغذاء رخيصا بما أنها نهبت العوالم الجديدة ودمرت الحياة الإيكولوجية فيها كما دمرت حيوات الأفراد عبر تعزيز ثقافة العبودية والاستغلال والاضطهاد علاوة على آثارها في جميع مناحي الحياة. يأخذنا هذا الكتاب في رحلة مع الاكتشافات الكبرى التي شهدها العالم القديم وكيف كانت تلك الاكتشافات مدخلا لبروز عصور دموية ومريعة، علاوة على تطرقه إلى دور الأوبئة والجوائح في بروز فكرة الاستعمار بشكلها الحالي. يمكن القول إن هذا الكتاب من أبرز الكتب التي تؤرخ للعالم من منظور مختلف ومتحرر من التحيزات والمركزية الأوروبية التي سادت في أغلب البحوث الأكاديمية.
BOOK
Factors affecting students’ entrepreneurial intentions: a systematic review (2005–2022) for future directions in theory and practice
Entrepreneurship has been viewed as a critical contributor and an economic engine in a country for creating new jobs and it is crucial for graduates to alter their mindset to become self-employed. Thus, it is necessary to synthesize the factors that impact the entrepreneurial intentions (EI) of students at tertiary level. The aim of this research is twofold; first to identify the factors which have been most studied in the literature and second, to determine which factors are less explored to measure the EI of students. This research adopts the systematic review approach to identify various studies conducted between 2005 to June 2022. The paper further adopted citation analysis and identified the 36 most impactful studies in this area of research. Next, the thematic analysis was conducted and seven main themes (factors) (cognitive, personality, environmental, social, educational, contextual and demographic) of EI determinants were identified. The analysis of the papers clearly demonstrated that the TPB model and cognitive factors dominate this area of research. Furthermore, over half of the studies are conducted in Asia, hence it is important to explore other regions such as Africa, America and Europe and other comparative studies between various regions. The study offers avenues for future research and practical implications of the study for the practitioners.
Journal Article
Subversion of Immune Response by Human Cytomegalovirus
Human cytomegalovirus (HCMV) is the most common cause of congenital infections and is an important pathogen in immunocompromised individuals. Despite a robust host immune system, HCMV able to replicate, evade host defenses, establish latency for life. A significant portion of HCMV genome dedicated to encode gene products for modulation of host immune response. Growing number of HCMV gene products are being recognized to play role in immune evasion. Information on viral immune evasion mechanisms by which HCMV persists in host will be useful in devising antiviral intervention strategies and development of new vaccines. This minireview provides a brief overview of immune evasion strategy adapted by HCMV by utilizing its gene products in modulation of host immune response.
Journal Article
Investigation on the synthesis and photocatalytic activity of activated carbon–cerium oxide (AC–CeO2) nanocomposite
Nano-sized photocatalyst cerium oxide (CeO
2
) particles and activated carbon–cerium oxide (AC–CeO
2
) composite are prepared by facile hydrothermal technique. Their properties are analyzed by subjecting them to characterization techniques such as powder X-ray diffraction (PXRD), high-resolution scanning electron microscopy (HRSEM), energy dispersive X-ray analysis (EDX), high-resolution transmission electron microscopy (HRTEM), Fourier transform infra-red spectroscopy (FTIR) and Raman spectroscopy. The photocatalytic activity of the prepared samples is monitored by UV–visible spectrophotometer. The PXRD, FTIR, Raman and EDX analyses confirm the formation of CeO
2
nanoparticles. The PXRD studies revealed that the CeO
2
nanoparticles and AC–CeO
2
nanocomposite have face centered cubic structure. The average crystallite size of CeO
2
nanoparticles and AC–CeO
2
nanocomposite, estimated using Scherrer formula, is found to be 21 nm and 7 nm. The HRSEM images show that the CeO
2
nanoparticles and AC–CeO
2
nanocomposite have spherical morphology and some agglomeration. The HRTEM images strongly confirm spherical morphology of both CeO
2
nanoparticles and AC–CeO
2
nanocomposite. The particle size of the CeO
2
nanoparticles and AC–CeO
2
nanocomposite are in the size range 20–30 nm and 7–15 nm, respectively. The selected area electron diffraction (SAED) patterns reveal that both samples are polycrystalline in nature. The photocatalytic activity of the synthesized CeO
2
nanoparticles and AC–CeO
2
nanocomposite is measured by degrading methylene blue dye under solar radiation. The photocatalytic activity study shows that the AC–CeO
2
nanocomposite has a degradation efficiency of 94% in 1 h for methylene blue, which is remarkably high when compared to that of CeO
2
nanoparticles.
Journal Article
Cytokine Signature Associated with Disease Severity in Dengue
Dengue is the most rapidly spreading viral disease transmitted by the bite of infected Aedes mosquitos. The pathogenesis of dengue is still unclear; although host immune responses and virus serotypes have been proposed to contribute to disease severity. In this study, we examined the circulating dengue virus (DENV) and measured plasma levels of inflammatory mediators. Ninety-eight patients during a dengue outbreak in eastern India in 2016 were included in the study. The presence of DENV was demonstrated by detecting NS1 antigen; IgM capture ELISA and serotypes were discriminated by type-specific RT-PCR and/or sequencing. Plasma samples were assayed for 41-plex cytokine/chemokines using multiplex Luminex assay. Eighty-five (87%) samples were positive by NS1/IgM capture ELISA/RT-PCR. All four serotypes of DENV were detected in this outbreak, with DENV-2 as the predominant type, seen in 55% of cases. Mixed infections were seen in 39% of subjects. Among the host inflammatory biomarkers, GM-CSF, IFN-γ, IL-10, IL-15, IL-8, MCP-1, IL-6, MIP-1β, and TNF-α levels were significantly increased in dengue with and without warning signs, in severe dengue patients in comparison to healthy controls. Four cytokines IFN-γ, GM-CSF, IL-10, and MIP-1β correlated significantly with disease severity and could serve as potential predictor for disease severity. Information on the host biomarkers and the dengue serotype may help guide in optimizing effective intervention strategies.
Journal Article
Spatial transcriptomics reveals discrete tumour microenvironments and autocrine loops within ovarian cancer subclones
High-grade serous ovarian carcinoma (HGSOC) is genetically unstable and characterised by the presence of subclones with distinct genotypes. Intratumoural heterogeneity is linked to recurrence, chemotherapy resistance, and poor prognosis. Here, we use spatial transcriptomics to identify HGSOC subclones and study their association with infiltrating cell populations. Visium spatial transcriptomics reveals multiple tumour subclones with different copy number alterations present within individual tumour sections. These subclones differentially express various ligands and receptors and are predicted to differentially associate with different stromal and immune cell populations. In one sample, CosMx single molecule imaging reveals subclones differentially associating with immune cell populations, fibroblasts, and endothelial cells. Cell-to-cell communication analysis identifies subclone-specific signalling to stromal and immune cells and multiple subclone-specific autocrine loops. Our study highlights the high degree of subclonal heterogeneity in HGSOC and suggests that subclone-specific ligand and receptor expression patterns likely modulate how HGSOC cells interact with their local microenvironment.
Intratumoural heterogeneity in high-grade serous ovarian carcinoma (HGSOC) remains to be explored. Here, the authors perform spatial transcriptomics and reveal a high degree of subclonal heterogeneity in HGSOC.
Journal Article
Entropy guided multi level feature fusion network for high precision content based image retrieval
Content-based image retrieval (CBIR) is essential for managing and searching massive image repositories across a wide variety of applications. Nevertheless, some traditional CBIR systems exhibit low retrieval accuracy because they use predetermined feature weights, lack semantic gaps, and poorly exploit heterogeneous visual features. To overcome such difficulties, the present study will introduce a multi-feature adaptive CBIR framework that combines deep and handcrafted features using an information entropy-based fusion and a trust-based weighting system. Deep convolutional models, combined with complementary low-level descriptors, are used to extract discriminative features in the proposed approach. A PageRank-based similarity propagation strategy is also used to narrow image ranking by leveraging similarity relationships across the globe. Evaluation is performed using standard retrieval measures, such as Mean Average Precision (mAP), Precision at K, Recall at K, and NDCG. The experimental results show that the proposed approach consistently improves performance across benchmark datasets. The framework boosts mAP by up to 8.6% over traditional fixed-weight fusion methods, while Precision@10 and NDCG@10 increase by 6.2% and 7.4%, respectively. The statistical analysis shows that these improvements are significant at the 95% confidence level, indicating that retrieval behavior is robust and reliable. These findings confirm the efficiency of entropy-driven adaptive fusion and ranking refinement in overcoming the major drawbacks of current CBIR systems, and the suggested framework is appropriate for large-scale image search in practice.
Journal Article