43 research outputs found
Hopf-Galois structures of squarefree degree
Get PDFThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordLet n be a squarefree natural number, and let G, Γ be
two groups of order n. We determine the number of Hopf-Galois
structures of type G admitted by a Galois extension of fields with
Galois group isomorphic to Γ. We give some examples, including
a full treatment of the case where n is the product of three primes
Counting Hopf-Galois structures on cyclic field extensions of squarefree degree
Get PDFThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.We investigate Hopf-Galois structures on a cyclic field extension L/K of squarefree degree n. By a result of Greither and Pareigis, each such Hopf-Galois structure corresponds to a group of order n, whose isomorphism class we call the type of the Hopf-Galois structure. We show that every group of order n can occur, and we determine the number of Hopf-Galois structures of each type. We then express the total number of Hopf-Galois structures on L/K as a sum over factorisations of n into three parts. As examples, we give closed expressions for the number of Hopf-Galois structures on a cyclic extension whose degree is a product of three distinct primes. (There are several cases, depending on congruence conditions between the primes.) We also consider one case where the degree is a product of four primes.The first-named author acknowledges support from The Higher Committee for Education Development in Iraq
UDMA photo-cured adhesive systems with enhanced mechanical properties for treating dental caries
No full textDental caries are a global oral health disease caused by acidogenic bacterial on teeth whereby acid causes demineralization, loss of ions, from the tooth into the saliva. The resulting cavities can be filled with light-cured, composite, resin restorations which are less toxic than amalgam, less expensive than gold and the resin can match the natural tooth color. However, composite resins tend to suffer from polymerization shrinkage after exposure to light, this can result in a gap forming between the adhesive layer at the base of the composite restoration and the tooth surface. The gap occurs due to the combination of polymer shrinkage and weak bonding between the adhesive layer and dental tissue, this then permits microleakage and eventually secondary caries to develop.
A Dental adhesive system acts as the key intermediate layer between a composite resin restoration and the tooth tissues (enamel and dentin). Ideally, the adhesive is able to penetrate into a roughened, porous enamel surface and into open tubules in dentin, hence forming a strong interlocking bond call a hybrid layer. The properties of the hybrid layer depend on the chemical composition of the adhesive system, including the monomers, photointiators, and additives, as well as its mechanical and rheological properties.
The aim of this thesis was to develop a new photo-cured dental adhesive with improved rheological and mechanical properties to enable a good interlocking hybrid layer and reduce gap formation. Firstly, commercially available products, including self-etch and three-step adhesive systems, were investigated, applied to cow teeth, and evaluated. Graphene and hydroxyapatite were blended with the three-step adhesive as an additive in an attempt to improve performance of the hybrid layer. Secondly, a new adhesive system was developed composed of high and low molecular weight monomers, diurethane dimethacrylate (UDMA) and methyl methacrylate (MMA), respectively. Thirdly, graphene and hydroxyapatite were added in different weight percentages to UDMA-MMA blends to optimize the mechanical properties of the photo-cured adhesive system. The viscosity, mechanical properties (using nanoindentation and tensile test), and degree of conversion (using FTIR and micro-Raman) were characterized for the UDMA-MMA blends with and without additives. Samples were imaged using optical microscopy, helium ion microscopy, and scanning electron microscopy, and surface topography was viewed using AFM. Thermography was used to monitor curing rate and temperature during curing.
For the commercial adhesive systems, results indicate that gap formation occurs between the adhesive and tooth tissues, which is related to the weak adhesive and hybrid layers. For the UDMA-MMA blends, results indicate that the viscosity and mechanical properties may be tuned and optimized to improve adhesion. For example, low weight % UDMA in MMA provides low viscosity, which allows penetration into tubules in the dentin and enamel forming a good hybrid layer while still providing good mechanical properties. For UDMA-MMA blends addition of even a small weight % of graphene or hydroxyapatite gave results indicating that mechanical properties are significantly increased while viscosity can be tailored for the application. The enhanced mechanics are due to changes in bonding when the additives are present. Graphene provided a more significant increase in mechanical properties than hydroxyapatite as the additive. It is concluded that UDMA-MMA blends or UDMA-MMA blends with suitable additives are potentially a new and improved option for photo-cured dental adhesive system with the potential to avoid gap formation and microleakage.Ph.D.Includes bibliographical reference
Hopf-Galois structures on separable field extensions of degree
Get PDFIn 2020, Alabdali and Byott described the Hopf-Galois structures arising on
Galois field extensions of squarefree degree. Extending to squarefree
separable, but not necessarily normal, extensions is a natural next step.
One must consider now the interplay between two Galois groups
and , where is the
Galois closure of . In this paper, we give a characterisation and
enumeration of the Hopf-Galois structures arising on separable extensions of
degree where and are distinct odd primes. This work includes the
results of Byott and Martin-Lyons who do likewise for the special case that
.Comment: 30 pages. arXiv admin note: text overlap with arXiv:2102.05759 by
other authors Author comment: this is known and has been cleared with the
relevant author
Employing bibliometric analysis on research published in Pakistan Journal of Medical and Health Sciences from 2019 – 2009.
Get PDFIntroduction: Pakistan Journal of Medical and Health Sciences is peer review and indexed in the Scopus-Elsevier database. This study signifies the participation of (PJMHS) in the research productivity, published from 2019 - 2009.
Material and Methods: The records of the published data retrieved from PJMHS website and Scopus-Elsevier database for tabulation in MS Office Excel Sheet. Frequency of publications, type of documents, usage of pages, citations, and association of the first author with their countries.
Results: Total 3817 documents written by 15401 (4%) authors in seven categories published in 43 issues. An average of (2.8%) pages consumed with getting of 896 (23.4%) citations in publications. Collaboration of three authors contributed 1339 (36.6%) documents and got first slot, and four authors 3344 (21.7%) added 836 (22%) of documents. The first authors affiliated with 29 countries around the globe participated in publications; Pakistan with 3484 (91%), Iran 79 (2%), Indonesia 77 (2%), and Kingdome of Saudi Arabia 65 (1.7%) stand on top places.
Conclusion: Pakistan Journal of Medical and Health Sciences (PJMHS) is a peer-reviewed journal published continuously and facilitates research communities of medical and health sciences to get their attention in sharing ideas on a reciprocal basis from similar specialties or sub-specialties of common disciplines
Safety and Efficacy of Atogepant for the Preventive Treatment of Migraines in Adults: A Systematic Review and Meta-Analysis
No full textBackground: Migraine is a common neurological condition marked by unilateral recurrent pulsating headaches, often associated with systemic signs and symptoms. Recently, calcitonin gene-related peptide (CGRP) antagonists, including atogepant, an oral CGRP receptor antagonist, have emerged as effective and safe treatments. The current study sought to assess the efficacy and safety of atogepant for preventing episodic migraines in adults. Methods: A comprehensive search, following PRISMA guidelines, was conducted using PubMed, Web of Science, and Cochrane Library to identify randomized, double-blind, placebo-controlled trials published up to June 2024. Results: The studies included adult participants with episodic migraine treated with atogepant. The primary outcomes assessed were changes in mean monthly migraine days (MMDs) and monthly headache days (MHDs) over 12 weeks. Secondary outcomes included reduction in acute medication use, 50% responder rates, and adverse events. A meta-analysis using a random-effects model was performed to evaluate efficacy and safety. Six trials with 4569 participants were included. Atogepant significantly reduced mean monthly migraine days (MMDs) and monthly headache days (MHDs) compared to placebo at all doses (10 mg, 30 mg, 60 mg), with the 60 mg dose showing the greatest reduction (mean difference: −1.48 days, p < 0.001). Significant reductions in acute medication use and improved 50% responder rates were also observed for all doses. The safety profile of atogepant was favorable, with common adverse events being mild to moderate, such as constipation and nausea. There were no significant differences in serious adverse events between the atogepant and placebo groups. Conclusions: Atogepant is an effective and well-tolerated option for preventing episodic migraines, showing significant reductions in migraine frequency and acute medication use. However, further studies are necessary to assess its long-term safety and efficacy, especially at higher doses, and to investigate its potential role in personalized treatment strategies for migraine prevention
Stress Hyperglycemia as a Prognostic Indicator of the Clinical Outcomes in Patients with Stroke: A Comprehensive Literature Review
No full textBackground: Stress hyperglycemia (SH), a transient elevation in blood glucose levels during acute stress such as stroke, has been increasingly recognized as a critical determinant of clinical outcomes. This review aims to evaluate the association between SH and clinical outcomes across different stroke subtypes and its role as a prognostic indicator. Methods: The current literature review was conducted through a comprehensive literature search of PubMed, Scopus, and Web of Science electronic databases. Initial title and abstract screening was conducted by two independent reviewers depending on the relevance to the topic of interest. Final study inclusion was based on the clinical relevance and agreement between reviewers. Results: Current evidence links SH with higher stroke severity (Higher national institutes of health stroke scale (NIHSS)), larger infarct volumes, increased risk of hemorrhagic transformation, and worse functional recovery (Lower modified rankin scale (mRS)), especially in ischemic stroke. In hemorrhagic stroke, SH is associated with hematoma expansion, perihematomal edema, and worsening neurological function. Although SH has been shown to be a reliable stroke outcome predictor, there is no scientific consensus regarding the most reliable measurement method. The use of absolute blood glucose values may not accurately reflect SH, particularly in diabetic patients, where chronic baseline hyperglycemia complicates interpretation. This underscores the necessity for individualized assessment rather than a uniform interpretation. Clinically, the early detection of SH may provide enhanced monitoring and supportive care; however, rigorous glucose management remains contentious due to the risk of hypoglycemia. Conclusions: This review synthesizes evidence from recent studies and supports SH as a prognostic marker of both short- and long-term adverse outcomes in stroke patients. Further research is warranted to evaluate the efficacy of targeted glycemic treatments on such outcomes
Whole-Exome Sequencing Reveals Migraine-Associated Novel Functional Variants in Arab Ancestry Females: A Pilot Study
No full textMigraine, as the seventh most disabling neurological disease with 26.9% prevalence in Saudi females, lacks studies on identifying associated genes and pathways with migraines in the Arab population. This case control study aims to identify the migraine-associated novel genes and risk variants. More than 1900 Arab ancestry young female college students were screened: 103 fulfilled the ICHD-3 criteria for migraine and 20 cases confirmed in the neurology clinic were included for the study with age-matched healthy controls. DNA from blood samples were subjected to paired-end whole-exome sequencing. After quality control, 3365343 missense, frameshift, missense splice region variants and insertion–deletion (indels) polymorphisms were tested for association with migraine. Significant variants were validated using Sanger sequencing. A total of 17 (p-value 9.091 × 10−05) functional variants in 12 genes (RETNLB, SCAI, ADH4, ESPL1, CPT2, FLG, PPP4R1, SERPINB5, ZNF66, ETAA1, EXO1 and CPA6) were associated with higher migraine risk, including a stop-gained frameshift (-13-14*SX) variant in the gene RETNLB (rs5851607; p-value 3.446 × 10−06). Gene analysis revealed that half of the significant novel migraine risk genes were expressed in the temporal lobe (p-value 0.0058) of the cerebral cortex. This is the first study exploring the migraine risk of 17 functional variants in 12 genes among Saudi female migraineurs of Arab ancestry using whole-exome sequencing. Half of the significant genes were expressed in the temporal lobe, which expands migraine pathophysiology and early identification using biomarkers for research possibilities on personalised genetics
The research trends of emergency medical services in Saudi Arabia during the period 2004 - 2018.
No full textAim: This is retrospective study, the aim of this study is, to estimate the publications published in PubMed Indexed journals on the subject Emergency Medical Services (EMS) by authors participated as the first or as a participatory author associated with the institutes of Kingdome Saudi Arabia.
Methods: The data has been retrieved and collected from the PubMed/Medline database to tabulate publications in sub-specialties of emergency medical services, a pattern of author’s, annual growth and frequency of journals from the period 2009 – 2018 in Microsoft Excel 2010.
Results: There are n=241; 36.5% articles published in 88 journals in 15 years with an average of 16% articles per annum. The n=1290; 5.3% participated in the contribution of 241 articles in 15 years. Total n=61; 25.3% institutes published 241 articles. The majority n=181; 75.1% articles produced by 13, followed by n=12; 0.8% institutes and n=36; 0.4% out of 61 institutes. King Saud University, Riyadh take lead and presents n=48; 20% articles as single institute. The majority articles n=206; 85.4% were written collaboratively by multi-authors out of 241 articles. Solo or single n=35; 14.5% articles were written similar to n=35; 14.5% articles by two authors. There are 19 subjects has been considered in research, Hospital Management & Patient Transportation n=33; 13.6% with following Education (Emergency Medical Services / Sciences) n=32; 13.2%, and Trauma & General Surgery n=29; 12% take lead to researchers and got preferences to wright. In 15 years total n=241; 16% of articles were published in 88 journals. Saudi Medical Journal published maximum n=42; 24.1%, articles in the studied period.
Conclusion: This study determined the significant involvement of emergency medical service providers in producing research literature published in reputed journals. It also shows that the Government of Saudi Arabia and its society are conscious about the handling of man-made or nature made disasters with rapid respons
Laser Doppler Flare Imaging and Quantitative Thermal Thresholds Testing Performance in Small and Mixed Fiber Neuropathies.
No full textSmall fiber neuropathy might be a part of typical mixed small and large fiber neuropathy, or a distinct entity, affecting exclusively small nerve fibers.Explore the utility of small nerve fiber testing in patients with clinical presentation suggesting small fiber neuropathy, with and without evidence for concomitant large fiber neuropathy.Patients attending the neuromuscular clinic from 2012 to 2015 with a clinical presentation suggesting small nerve fiber impairment, who had Laser Doppler flare imaging (LDIFlare) and quantitative thermal testing (QTT) were evaluated for this study. Patients with clinical or electrophysiological evidence for concomitant large fiber neuropathy were not excluded.The sensitivities of LDIFlare, cooling and heat threshold testing were 64%, 36%, and 0% respectively for clinically highly suggestive small fiber neuropathy, 64%, 56%, and 19% respectively for mixed fiber neuropathy, and 86%, 79%, and 29% respectively for diabetic mixed fiber neuropathy.LDIFlare and cooling thresholds testing are non-invasive small nerve fiber testing modalities, with moderate performance in patients with small and mixed fiber neuropathy, and excellent performance in diabetic mixed fiber neuropathy
