206 research outputs found
Physicochemical Analysis of the Aqueous Extracts of Six Nigerian Medicinal Plants
Purpose: Extracts of Picralima nitida seeds, Detarium microcarpum stem bark, Aframomum melagueta seeds, Terminalia catappa leaves, Acacia nilotica pods, and Morinda lucida stem bark, are under consideration for development into suitable dosage forms for treating diabetes mellitus, sickle cell anemia and malaria. This study aimed at evaluating the extracts for features that would influence decisions on them in the course of the project.Methods: Physicochemical determinations, including proximate analysis, were done by sensory examination, and gravimetric and electrochemical techniques. Thin layer chromatography was carried out with normal silica plates using various solvent systems. Metallic content analyses were carried out by atomic absorption spectroscopy.Results: The extracts were dry but hygroscopic, with a loss on drying range of 0.26 – 12.00 %w/w. The pH of the 5 - 10 % solutions ranged 5 - 7. No harsh sensory effects, such as lacrimation, were detected in any of the extracts. Total ash ranged from 3.79 – 20.68 %w/w, while acid insoluble ash values were below detection. The extracts yielded reproducible chromatograms on normal silica plates developed with various solvent systems. Copper, present at 0.16 - 0.58 mg/100g, was the lowest occurring microelement while calcium content was highest, at 41 - 216 mg/100g. The level of lead, a heavy metal, was 0.05 - 0.22 mg/100g.Conclusion: The results confirm that the extracts require no special handling, possess characteristics that would allow their possible development into solid dosage forms, and that their lead contentscomplied with official limits.Keywords: Aqueous extract, Picralima nitida, Detarium microcarpum, Aframomum melagueta, Terminalia catappa, Acacia nilotica, Morinda lucida
Cosmic Ray Spectra in Nambu-Goldstone Dark Matter Models
We discuss the cosmic ray spectra in annihilating/decaying Nambu-Goldstone
dark matter models. The recent observed positron/electron excesses at PAMELA
and Fermi experiments are well fitted by the dark matter with a mass of 3TeV
for the annihilating model, while with a mass of 6 TeV for the decaying model.
We also show that the Nambu-Goldstone dark matter models predict a distinctive
gamma-ray spectrum in a certain parameter space.Comment: 16 pages, 4 figure
Realization of Minimal Supergravity
Minimal supergravity mediation of supersymmetry breaking has attracted much
attention due to its simplicity, which leads to its predictive power. We
consider how Nature possibly realizes minimal supergravity through inflationary
selection of the theory. Minimality is impressively consistent with the present
observational bounds and it might be tested with the aid of low-energy soft
parameters obtained in future experiments.Comment: 18 pages, 5 figure
Viable Supersymmetry and Leptogenesis with Anomaly Mediation
The seesaw mechanism that explains the small neutrino masses comes naturally
with supersymmetric (SUSY) grand unification and leptogenesis. However, the
framework suffers from the SUSY flavor and CP problems, and has a severe
cosmological gravitino problem. We propose anomaly mediation as a simple
solution to all these problems, which is viable once supplemented by the
D-terms for U(1)_Y and U(1)_{B-L}. Even though the right-handed neutrino mass
explicitly breaks U(1)_{B-L} and hence reintroduces the flavor problem, we show
that it lacks the logarithmic enhancement and poses no threat to the framework.
The thermal leptogenesis is then made easily consistent with the gravitino
constraint.Comment: 5 pages, one figure, uses Revtex4; Discussion on the upper bound on
the LSP mass added. The version published in PR
Perceptions of Nigerian medical students regarding their preparedness for precision medicine: a cross-sectional survey in Lagos, Nigeria
Background
Advances in precision medicine in Nigeria suggest improving genomics education and competency among healthcare practitioners to facilitate clinical translation. Due to the scarcity of research in this area, this study aimed to assess Nigerian medical students’ perceptions about their preparedness to integrate precision medicine into their future clinical practice.
Methods
This was an institution-based cross-sectional study of medicine and surgery students in their clinical years attending the two fully accredited colleges of medicine in Lagos, Nigeria, between April and October 2022 using an adapted tool administered via Google Forms. The survey assessed their awareness, perceptions about knowledge, ability, and attitudes toward precision medicine, ethical concerns, and perceptions about their education in precision medicine. Multivariate linear regression models were used to assess factors associated with students’ perceptions of their knowledge, ability, and attitudes.
Results
A total of 300 students completed the questionnaires with a response rate of 40%. Awareness of genomic medicine terminology was high (92.0%). Responses to knowledge and ability questions revealed notable gaps, however, respondents had positive attitude scores overall. Higher medical school year was independently associated with lower knowledge (ptrend = 0.003) and ability (ptrend = 0.005) scores, and knowledge score was independently associated with a higher ability score (β: 0.76 95%CI: 0.67, 0.84; p Conclusion
Despite high awareness of precision medicine terminology and overall positive attitudes, our findings highlight gaps in knowledge and ability to integrate genomics into the care of patients and a need to improve precision medicine education among Nigerian medical students
F-theory, GUTs, and the Weak Scale
In this paper we study a deformation of gauge mediated supersymmetry breaking
in a class of local F-theory GUT models where the scale of supersymmetry
breaking determines the value of the mu term. Geometrically correlating these
two scales constrains the soft SUSY breaking parameters of the MSSM. In this
scenario, the hidden SUSY breaking sector involves an anomalous U(1)
Peccei-Quinn symmetry which forbids bare mu and B mu terms. This sector
typically breaks supersymmetry at the desired range of energy scales through a
simple stringy hybrid of a Fayet and Polonyi model. A variant of the
Giudice-Masiero mechanism generates the value mu ~ 10^2 - 10^3 GeV when the
hidden sector scale of supersymmetry breaking is F^(1/2) ~ 10^(8.5) GeV.
Further, the B mu problem is solved due to the mild hierarchy between the GUT
scale and Planck scale. These models relate SUSY breaking with the QCD axion,
and solve the strong CP problem through an axion with decay constant f_a ~
M_(GUT) * mu / L, where L ~ 10^5 GeV is the characteristic scale of gaugino
mass unification in gauge mediated models, and the ratio \mu / L ~
M_(GUT)/M_(pl) ~ 10^(-3). We find f_a ~ 10^12 GeV, which is near the high end
of the phenomenologically viable window. Here, the axino is the goldstino mode
which is eaten by the gravitino. The gravitino is the LSP with a mass of about
10^1 - 10^2 MeV, and a bino-like neutralino is (typically) the NLSP with mass
of about 10^2 - 10^3 GeV. Compatibility with electroweak symmetry breaking also
determines the value of tan(beta) ~ 30 +/- 7.Comment: v3: 94 pages, 9 figures, clarification of Fayet-Polonyi model and
instanton corrections to axion potentia
Soft Spectrum in Yukawa-Gauge Mediation
We introduce a model independent parametrization for a subclass of gauge
mediated theories, which we refer to as Yukawa-gauge mediation. Within this
formalism we study the resulting soft masses in the visible spectrum. We find
general expressions for the gaugino and scalar masses. Under generic
conditions, the gaugino mass is screened, vanishing at first order in the SUSY
breaking scale.Comment: 22 pages, 4 figures; v2: minor corrections, published versio
Abelian Hidden Sectors at a GeV
We discuss mechanisms for naturally generating GeV-scale hidden sectors in
the context of weak-scale supersymmetry. Such low mass scales can arise when
hidden sectors are more weakly coupled to supersymmetry breaking than the
visible sector, as happens when supersymmetry breaking is communicated to the
visible sector by gauge interactions under which the hidden sector is
uncharged, or if the hidden sector is sequestered from gravity-mediated
supersymmetry breaking. We study these mechanisms in detail in the context of
gauge and gaugino mediation, and present specific models of Abelian GeV-scale
hidden sectors. In particular, we discuss kinetic mixing of a U(1)_x gauge
force with hypercharge, singlets or bi-fundamentals which couple to both
sectors, and additional loop effects. Finally, we investigate the possible
relevance of such sectors for dark matter phenomenology, as well as for low-
and high-energy collider searches.Comment: 43 pages, no figures; v2: to match JHEP versio
Higgs Boson Mass in Low Scale Gauge Mediation Models
We consider low scale gauge mediation models with a very light gravitino
m_{3/2}~16 eV, in the light of recent experimental hints on the Higgs boson
mass. The light gravitino is very interesting since there is no gravitino
over-production problem, but it seems difficult to explain the Higgs boson mass
of ~125 GeV. This is because of the conflict between the light gravitino mass
and heavy SUSY particle masses needed for producing the relatively heavy Higgs
boson mass. We consider two possible extensions in this paper: a singlet
extension of the Higgs sector, and strongly coupled gauge mediation. We show
that there is a large parameter space, in both scenarios, where the Higgs boson
mass of ~125 GeV is explained without any conflict with such a very light
gravitino.Comment: 23 pages, 5 figure
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