A Search for Dark Higgs Bosons

Recent astrophysical and terrestrial experiments have motivated the proposal of a dark sector with GeV-scale gauge boson force carriers and new Higgs bosons. We present a search for a dark Higgs boson using 516 fb-1 of data collected with the BABAR detector. We do not observe a significant signal and we set 90% confidence level upper limits on the product of the Standard Model-dark sector mixing angle and the dark sector coupling constant.Comment: 7 pages, 5 postscript figures, published version with improved plots for b/w printin

B0 meson decays to rho0 K*0, f0 K*0, and rho-K*+, including higher K* resonances

We present branching fraction measurements for the decays B0 -> rho0 K*0, B0 -> f0 K*0, and B0 -> rho- K*+, where K* is an S-wave (K pi)_0* or a K*(892) meson; we also measure B0 -> f0 K_2*(1430)^0. For the K*(892) channels, we report measurements of longitudinal polarization fractions (for rho final states) and direct CP-violation asymmetries. These results are obtained from a sample of (471.0 +/- 2.8) x 10^6 BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e+ e- collider at the SLAC National Accelerator Laboratory. We observe rho0 K*(892)^0, rho0 (K pi)_0^{*0}, f0 K*(892)^0, and rho- K*(892)+ with greater than 5 sigma significance, including systematics. We report first evidence for f0 (K pi)_0^{*0} and f0 K_2*(1430)^0, and place an upper limit on rho- (K pi)_0^{*+}. Our results in the K*(892) channels are consistent with no direct CP-violation.Comment: 17 pages, 6 postscript figures, submitted to Phys. Rev.

Formulation and evaluation of Albendazole microcapsules for colon delivery using chitosan

AbstractObjectiveTo formulate and evaluate Albendazole microcapsules using chitosan, a natural polymer for colon-specific delivery for better treatment of helminthiasis, filariasis, colorectal cancer, avoiding the side effects.MethodsThe Albendazole microcapsules were prepared by the use of different concentrations of sodium alginate, chitosan and hydroxypropyl methylcellulose (HPMC). The polysaccharides chitosan reacted with sodium alginate in the presence of calcium chloride to form microcapsules with a polyelectrolyte complex membrane by electrostatic interactions between the two oppositely charged polymers. The microcapsules were then studied for entrapment efficiency, drug-polymer compatibility and surface morphology. In vitro drug release study in presence and absence of cecal content were also studied. Further, kinetic modellings were employed to find out release mechanisms.ResultsAlbendazole loaded microspheres showd high entrapment efficiency (72.8%) and the microcapsules were free flowing, non aggregated and spherical, between 600 and 1000 μm in diameter. The surface of microcapsules were found to be porous and wavy. The FT-IR spectrum showed that there is no interaction between the polymer and the drug. The in vitro drug release study found to be affected by change in chitosan, sodium alginate and HPMC concentration. The microcapsules with 2.5% sodium alginate and 0.4% chitosan shown minimum release in gastrointestinal simulated condition but shows maximum drug release at the end of 24th hour in presence of cecal content. The rate of drug release follows Korsmeyer-peppas model that was the drug release is by diffusion and erosion.ConclusionsThe study reveals that Albendazole loaded chitosan-alginate based microsphere can be used effectively for the colon targeting

Isolation of the mucilages from Hibiscus rosasinensis linn. and Okra (Abelmoschus esculentus linn.) and studies of the binding effects of the mucilages

AbstractObjectiveTo isolate and evaluate comparatively the binding efficacy of the mucilages obtained from the plants of Hibiscus rosasinensis and Okra (Abelmoschus esculentus).MethodsExtraction of mucilages from the leaves of Hibiscus and pods of Okra (Ladies finger) was carried out by a cold maceration process. The extracted mucilages were subjected to various physicochemical properties for its suitability as an excipient in the formulation of tablet dosage form. Different concentrations (10, 8, 5, 2 and 1% w/v) of binder solutions of Hibiscus and Okra were used for the formulation of tablets and the formulated tablets were evaluated by studying the standard parameters like diameter, thickness, weight variation, hardness, friability, disintegration and in vitro dissolution. Stability studies of the formulated tablets were conducted for four weeks.ResultsThe formulated tablets prepared using the mucilages of both Hibiscus and Okra had good appearance. The in vitro drug release profile of the tablets prepared using Okra mucilage had an optimum of 90% at a mucilage concentration of 1% w/v concentration mucilage itself within 4 h.ConclusionsAccording to the observations, the lower concentration levels of Okra can be used as an alternative binder to starch. The higher concentration levels of Okra mucilage show a slow and sustained release, and can be considered as an alternative natural excipient in the modified drug delivery systems. At the same time, the above natural excipient of Hibiscus mucilage could be used as a platform for prolonged release if its binder concentrations are increased

Evaluation of a new tablet excipient from the leaves of Mussaenda frondosa

ABSTRACT Mussaenda frondosa Linn, family, Rubiacae, traditionally used in Indian folk medicine. Here an effort was made to investigate the efficacy of the mucilage obtained from the leaves of Mussaenda frondosa Linn as tablet excipient. The mucilage extracted from the leaves of Mussaenda frondosa Linn and studied for various physicochemical properties. Tablets were manufactured using extracted mucilage as the binding agent and comparison was made against the tablets prepared with starch paste as the standard binder on studying the standard parameters like diameter, thickness, weight variation, hardness, friability, disintegration and in-vitro dissolution study. Stability studies were conducted for 4 weeks periods.The mucilage shows good physicochemical properties that assessed as an excipient in formulation of tablets. The tablets prepared by using 5-10% mucilage shows the release rate in a sustained manner and that of 1% shows the drug release more than 90% within 4 h, which can be considered as the ideal concentration for preparation of tablets. At the end of 4 th week appreciable changes was not observed for the stability study. Mussaenda frondosa mucilage could be used as a good binding agent at very low concentrations. This can be used for sustaining the drug release from tablets, since the prepared tablets produced a sticky film of hydration on the surface, which ultimately reduces drug release rate and hence it can be evaluated for its efficacy to sustain the drug release

Modeling of Virion Collisions in Cervicovaginal Mucus Reveals Limits on Agglutination as the Protective Mechanism of Secretory Immunoglobulin A

<div><p>Secretory immunoglobulin A (sIgA), a dimeric antibody found in high quantities in the gastrointestinal mucosa, is broadly associated with mucosal immune protection. A distinguishing feature of sIgA is its ability to crosslink pathogens, thereby creating pathogen/sIgA aggregates that are too large to traverse the dense matrix of mucin fibers in mucus layers overlying epithelial cells and consequently reducing infectivity. Here, we use modeling to investigate this mechanism of “immune exclusion” based on sIgA-mediated agglutination, in particular the potential use of sIgA to agglutinate HIV in cervicovaginal mucus (CVM) and prevent HIV transmission. Utilizing reported data on HIV diffusion in CVM and semen, we simulate HIV collision kinetics in physiologically-thick mucus layers–a necessary first step for sIgA-induced aggregation. We find that even at the median HIV load in semen of acutely infected individuals possessing high viral titers, over 99% of HIV virions will penetrate CVM and reach the vaginal epithelium without colliding with another virion. These findings imply that agglutination is unlikely to be the dominant mechanism of sIgA-mediated protection against HIV or other sexually transmitted pathogens. Rather, we surmise that agglutination is most effective against pathogens either present at exceedingly high concentrations or that possess motility mechanisms other than Brownian diffusion that significantly enhance encounter rates.</p></div