1,067 research outputs found

    Dark/Visible Parallel Universes and Big Bang Nucleosynthesis

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    We develop a model for visible matter-dark matter interaction based on the exchange of a massive gray boson called herein the Mulato. Our model hinges on the assumption that all known particles in the visible matter have their counterparts in the dark matter. We postulate six families of particles five of which are dark. This leads to the unavoidable postulation of six parallel worlds, the visible one and five invisible worlds. A close study of big bang nucleosynthesis (BBN), baryon asymmetries, cosmic microwave background (CMB) bounds, galaxy dynamics, together with the Standard Model assumptions, help us to set a limit on the mass and width of the new gauge boson. Modification of the statistics underlying the kinetic energy distribution of particles during the BBN is also discussed. The changes in reaction rates during the BBN due to a departure from the Debye-Hueckel electron screening model is also investigated.Comment: Invited talk at the Workshops "CompStar: the physics and astrophysics of compact stars", Tahiti, June 4-8, 2012, "New Directions in Nuclear Astrophysics", Castiglion Fiorentino, Italy, June 18-22, 2012, and "Carpathian Summer School of Physics", Sinaia, Romania, June 24 - July 7, 2012. To be published in AIP Proceeding

    Characteristics of Referrals for Gender Dysphoria Over a 13-Year Period

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    PURPOSE: Our Pediatric Endocrinology Clinic has seen a sharp increase in referrals for gender dysphoria (GD) during recent years. However, the frequency and characteristics of referrals have not been objectively examined. METHODS: A retrospective chart review of referrals for GD during the past 13 years was performed. Variables analyzed included numbers of referrals per year, patient characteristics, comorbid conditions, and hormonal therapy. Timing of referral and eligibility for treatment were measured against established recommendations. RESULTS: Of 38 patients, 74% were referred during the last 3 years. Most patients presented late in puberty before a GD-specific psychological evaluation and few were eligible for hormonal treatment at baseline. Over half had psychiatric and/or developmental comorbidities. CONCLUSIONS: A dramatic increase in referrals for GD since 2002 was confirmed. Enhanced provider education and outreach regarding care of patients with GD are needed

    Bicalutamide as an Androgen Blocker With Secondary Effect of Promoting Feminization in Male-to-Female Transgender Adolescents

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    PURPOSE: The purpose of the study was to describe the novel use of bicalutamide in transgender youth. METHODS: This is a retrospective review of patients with gender dysphoria followed in the pediatric endocrine clinic at Riley Hospital for Children. RESULTS: Of 104 patients with gender dysphoria, 23 male-to-female adolescents received bicalutamide 50 mg daily as a second-line puberty blocker after insurance company denial of a gonadotropin-releasing hormone analog. Six patients received estrogen concurrently. Of 13 patients treated exclusively with bicalutamide seen in follow-up, 84.6% had breast development within 6 months, the majority being ā‰„ Tanner stage III. CONCLUSIONS: Bicalutamide may be an alternative to gonadotropin-releasing hormone analogs in transgender male-to-female youth who are also ready to undergo physical transition

    Voltage-sensitive gating of the Pannexin-1 channel

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    Since its discovery just over a decade ago, Pannexin-1 (Px1) has been recognized in a number of important physiological and pathophysiological processes such as taste, inflammation, and tumor suppression. This large-pore, polymodal ion channel was initially identified as ā€—voltage-dependent,ā€˜ though there have been no precise studies concerning the gating properties of Px1 to date. Because Px1 is expressed in excitable cells, identifying voltage-gating properties of Px1 was our primary goal. Using the two-electrode voltage clamp technique, we showed for the first time that Px1 is a weakly voltage-gated channel. Depolarizing voltages up to +200 mV revealed half-maximal activation at +51 mV and a weak voltage-dependence through generation of a complete Boltzmann activation curve. We also showed that Px1 activates in \u3c 3.5 ms, consistent with the time frame of action potentials (1-4 ms). Opening rates of Px1 also seemed to be very weakly voltage-dependent. Further, we showed that Px1 displays consistent current decay at depolarizing voltages greater than +100 mV. Additionally, using two cell systems to exogenously express Px1, we observed a marked decrease of functional Px1 expression within ~24 hours of injection. Taken together, our findings suggest that Px1 is a fast opening, voltage-sensitive channel that may have a number of mechanisms in place to prevent uncontrolled conductivity

    The Importance of Nightside Magnetometer Observations for Electromagnetic Sounding of the Moon

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    Understanding the structure and composition of the lunar interior is a fundamental goal in furthering our knowledge of the formation and subsequent evolution of the Earth-Moon system. Among various methods, electromagnetic sounding is a valuable approach to constraining lunar interior structure. Recent analyses of plasma and field observations provide a wealth of understanding about the dynamics of the lunar plasma environment. To perform Time Domain EM (TDEM) Sounding at the Moon, the first step is to characterize the dynamic plasma environment, and to be able to isolate geophysically induced currents from concurrently present plasma currents. The TDEM Sounding transfer function method focuses on analysis of the nightside observations when the Moon is immersed in the solar wind. This method requires two simultaneous observations: an upstream reference measuring the pristine solar wind, and one downstream at or near the lunar surface. This method was last performed during Apollo and assumed the induced fields on the nightside of the Moon expand as in an undisturbed vacuum within the wake cavity. Our results indicate that EM sounding of airless bodies in the solar wind must be interpreted via self-consistent plasma models in order to untangle plasma and induced field contributions, with implications not only at the Moon but at all airless bodies exposed to the solar wind. Nightside TDEM sounding has the capability to advance the state of knowledge of the field of lunar science. This requires magnetometer operations to withstand the harsh conditions of the lunar night

    Androgen receptor acetylation governs trans activation and MEKK1-induced apoptosis without affecting in vitro sumoylation and trans-repression function

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    This work was supported by grants from the NIH (R01CA86072 to R.G.P. and R01CA72038-01 to S.A.W.F.) and The Susan Komen Breast Cancer Foundation (to R.G.P.). R.T.H. and E.J. were supported by the Medical Research Council. Y.-G.Y. is supported by grant CA26504 to E. R. Stanley. Work conducted at the Albert Einstein College of Medicine was supported by Cancer Center Core National Institutes of Health grant 5-P30-CA13330-26.The androgen receptor (AR) is a nuclear hormone receptor superfamily member that conveys both traits repression and ligand-dependent trans-activation function. Activation of the AR by dihydrotestosterone (DHT) regulates diverse physiological functions including secondary sexual differentiation in the male and the induction of apoptosis by the JNK kinase, MEKK1. The AR is posttranslationally modified on lysine residues by acetylation and sumoylation. The histone acetylases p300 and P/CAF directly acetylate the AR in vitro at a conserved KLKK motif. To determine the functional properties governed by AR acetylation, point mutations of the KLKK motif that abrogated acetylation were engineered and examined in vitro and in vivo. The AR acetylation site point mutants showed wild-type trans repression of NF-kappaS, AP-1, and Sp1 activity; wild-type sumoylation in vitro; wild-type ligand binding; and ligand-induced conformational changes. However, acetylation-deficient AR mutants were selectively defective in DHT-induced trans activation of androgen-responsive reporter genes and coactivation by SRC1, Ubc9, TIP60, and p300. The AR acetylation site mutant showed 10-fold increased binding of the N-CoR corepressor compared with the AR wild type in the presence of ligand. Furthermore, histone deacetylase 1 (HDAC1) bound the AR both in vivo and in cultured cells and HDAC1 binding to the AR was disengaged in a DHT-dependent manner. MEKK1 induced AR-dependent apoptosis in prostate cancer cells. The AR acetylation mutant was defective in MEKK1-induced apoptosis, suggesting that the conserved AR acetylation site contributes to a pathway governing prostate cancer cellular survival. As AR lysine residue mutations that abrogate acetylation correlate with enhanced binding of the N-CoR repressor in cultured cells, the conserved AR motif may directly or indirectly regulate ligand-dependent corepressor disengagement and, thereby, ligand-dependent trans activation.Publisher PDFPeer reviewe
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