145 research outputs found
Mass dimension one fields with Wigner degeneracy: A theory of dark matter
Whatever dark matter is, it must be one irreducible unitary representation of
the extended Lorentz group or another. We here develop a formalism of mass
dimension one fermions and bosons of spin one half, and show that they provide
natural dark matter candidates. By construction, they are covariant under
space-time translations and boosts. However, incorporating the rotational
symmetry is non-trivial and requires introducing a two-fold Wigner degeneracy
thus doubling the degrees of freedom for particles and anti particles from two
to four. With Wigner degeneracy, we have a well-defined theory of mass
dimension one fields of spin one half that are physically distinct from the
Dirac field. They are local, Lorentz covariant and have positive definite free
Hamiltonians. The developed framework also has the potential to resolve the
cosmological constant problem, and supply dark energy.Comment: 12 page
Male Contraceptives: A New Frontier in Contraception Medicine
In the field of contraceptive studies, discussions primarily focus on the practice of women’s health and contraception. While it is true that unintended pregnancies and sexually transmitted diseases/infections (STI) pose major challenges in global public health, historically the burden of preventing these has largely fallen on women. Assuming that sexual intercourse requires an equal contribution between two partners, we hold that contraception and STI prevention should be a shared responsibility. Additionally, the ideal contraceptive method should prevent both unplanned pregnancies and STIs simultaneously. While abstinence remains the only 100% proven method of achieving such goals, it is not always practical or achievable in sexually active consenting or nonconsenting individuals. Because pregnancy occurs in a woman’s body, contraception has been regarded as a women’s health issue and not a general health issue. This dynamic is shifting. There is currently a paucity of male contraceptives and STI prevention methods on the market, but current trends in research and clinical practice promise to equally enable both women and men when making contraception choices. This paper aims to provide a comprehensive review of the male contraceptive methods currently available, as well as to highlight some of the most recently published work in the area of male contraceptive research
Alkyl substituted poly(p-phenylene vinylene)s by ring opening metathesis polymerisation
The ring opening metathesis polymerisation (ROMP) of three n-octyl substituted [2.2]paracyclophane-1,9-dienes, initiated by Grubbs ruthenium carbene complexes is reported.</p
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Simple Integer Risk Score to Determine Prognosis of Patients With Hypertension and Chronic Stable Coronary Artery Disease
Background: It is difficult to accurately determine prognosis of patients with hypertension and chronic stable coronary artery disease (CAD). Our aim was to construct a risk score for predicting important adverse events in this population. Methods and Results: Patients with hypertension and chronic stable CAD enrolled in the INternational VErapamil‐SR/Trandolapril STudy (INVEST) comprised the study cohort. Candidate predictor variables were obtained from patients with at least 1 postbaseline visit. Patients were divided into development (n=18 484) and validation cohorts (n=2054). Cox regression model identified predictors of the primary outcome: all‐cause mortality, myocardial infarction, or stroke at a mean follow‐up of 2.3 years. The hazard ratio of each variable was rounded to the nearest integer to construct score weights. A score 0 to 4 defined low‐risk, 5 to 6 intermediate‐risk and ≥7 high‐risk. The following variables were retained in the final model: age, residence, body mass index, on‐treatment heart rate and BP, prior myocardial infarction, heart failure, stroke/transient ischemic attack, smoking, diabetes, peripheral arterial disease, and chronic kidney disease. The primary outcome occurred in 2.9% of the low‐risk group, 6.5% of the intermediate‐risk group, and 18.0% of the high‐risk group (P for trend <0.0001). The model was good at discriminating those who had an event versus those who did not (C‐statistic=0.75). The model performed well in a validation cohort (C‐statistic=0.77). Conclusion: Readily available clinical variables can rapidly stratify patients with hypertension and chronic stable CAD into useful risk categories
Packed Red Blood Cell Transfusion Associates with Acute Kidney Injury After Transcatheter Aortic Valve Replacement
Background: Acute kidney injury after cardiac surgery significantly associates with morbidity and mortality. Despite not requiring cardiopulmonary bypass, transcatheter aortic valve replacement patients have an incidence of post-procedural acute kidney injury similar to patients who undergo open surgical aortic valve replacement. Packed red blood cell transfusion has been associated with morbidity and mortality after cardiac surgery. We hypothesized that packed red blood cell transfusion independently associates with acute kidney injury after transcatheter aortic valve replacement, after accounting for other risk factors.
Methods: This is a single-center retrospective cohort study of 116 patients undergoing transcatheter aortic valve replacement. Post-transcatheter aortic valve replacement acute kidney injury was defined by Kidney Disease: Improving Global Outcomes serum creatinine-based criteria. Univariate comparisons between patients with and without post-transcatheter aortic valve replacement acute kidney injury were made for clinical characteristics. Multivariable logistic regression was used to assess independent association of packed red blood cell transfusion with post-transcatheter aortic valve replacement acute kidney injury (adjusting for pre-procedural renal function and other important clinical parameters).
Results: Acute kidney injury occurred in 20 (17.2%) subjects. Total number of packed red blood cells transfused independently associated with post-procedure acute kidney injury (OR = 1.67 per unit, 95% CI 1.13–2.47, P = 0.01) after adjusting for pre-procedure estimated glomerular filtration rate (OR = 0.97 per ml/min/1.73m2, 95% CI 0.94–1.00, P = 0.05), nadir hemoglobin (OR = 0.88 per g/dL increase, CI 0.61–1.27, P = 0.50), and post-procedure maximum number of concurrent inotropes and vasopressors (OR = 2.09 per inotrope or vasopressor, 95% CI 1.19–3.67, P = 0.01).
Conclusion: Packed red blood cell transfusion, along with post-procedure use of inotropes and vasopressors, independently associate with acute kidney injury after transcatheter aortic valve replacement. Further studies are needed to elucidate the pathobiology underlying these associations
Dynamics of MHD Convection of Walters B Viscoelastic Fluid through an Accelerating Permeable Surface Using the Soret–Dufour Mechanism
The MHD convective Walters-B memory liquid flow past a permeable accelerating surface with the mechanism of Soret-Dufour is considered. The flow equation constitutes a set of partial differential equations (PDEs) to elucidate the real flow of a non-Newtonian liquid. The radiation thermo-physical parameters were employed based on the use of Roseland approximation. This implies the fluid employed in this exploration is optically thick. Utilizing suitable similarity terms, the flow equation PDEs were simplified to become total differential equations. The spectral homotopy analysis method (SHAM) was utilized to provide outcomes to the model. The SHAM involves the addition of the Chebyshev pseudospectral approach (CPM) alongside the homotopy analysis approach (HAM). The outcomes were depicted utilizing graphs and tables for the quantities of engineering concern. The mechanisms of Soret and Dufour were separately examined. The imposed magnetism was found to lessen the velocity plot while the thermal radiation term elevates the temperature plot because of the warm particles of the fluid.This research was funded by a grant of the Romanian Ministry of Research, Innovation and
Digitalization, project number PFE 26/30.12.2021, PERFORM-CDI@UPT100—The increasing of the
performance of the Polytechnic University of Timis, oara by strengthening the research, development
and technological transfer capacity in the field of “Energy, Environment and Climate Change” at the
beginning of the second century of its existence, within Program 1—Development of the national
system of Research and Development, Subprogram 1.2—Institutional Performance—Institutional
Development Projects—Excellence Funding Projects in RDI, PNCDI III.info:eu-repo/semantics/publishedVersio
TCT-523 Multicenter Registry for Peripheral Arterial Disease Interventions and Outcomes (XLPAD Registry)
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