1,344 research outputs found

    Mitochondrial Fusion Promotes Steroidogenesis in MA10 Leydig Cells

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    Infertility affects 1 out of every 6 couples, worldwide, with male infertility playing a primary factor in a third of all cases. Dysregulation of sex hormones is a major cause of infertility. Male hypogonadism is a condition in which the testis does not produce adequate concentrations of testosterone. Males suffering from hypogonadism can be born with the condition or develop it later in life, often from acute injury or infection. Male hypogonadism is treated with testosterone replacement to return testosterone levels to normal. However, one side effect of testosterone treatment is infertility. Understanding mechanisms that regulate the synthesis of sex steroids holds great potential to positively impact reproductive health and overall quality of life. Mitochondria play a key role in the synthesis of all steroid hormones. The first and rate-limiting step in the production of all steroid hormones is the transfer of cholesterol from the outer mitochondrial membrane to the inner membrane. In the current study, we examined the hypothesis that mitochondrial fusion promotes acute steroid synthesis in LH-responsive Leydig cells.https://digitalcommons.unmc.edu/surp2022/1005/thumbnail.jp

    Induced antiferromagnetism and large magnetoresistances in RuSr2(Nd,Y,Ce)2Cu2O10-d ruthenocuprates

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    RuSr2(Nd,Y,Ce)2Cu2O10-d ruthenocuprates have been studied by neutron diffraction, magnetotransport and magnetisation measurements and the electronic phase diagram is reported. Separate Ru and Cu spin ordering transitions are observed, with spontaneous Cu antiferromagnetic order for low hole doping levels p, and a distinct, induced-antiferromagnetic Cu spin phase in the 0.02 < p < 0.06 pseudogap region. This ordering gives rise to large negative magnetoresistances which vary systematically with p in the RuSr2Nd1.8-xY0.2CexCu2O10-d series. A collapse of the magnetoresistance (MR) and magnetisation in the pre-superconducting region may signify the onset of superconducting fluctuations.Comment: 22 pages, 11 figure

    Charge and orbital order in frustrated Pb3Mn7O15

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    The candidate magnetoelectric Pb3Mn7O15 has a structure consisting of 1/3 filled Kagome layers linked by ribbons of edge-sharing octahedra in the stacking direction. Previous reports have indicated a complex hexagonal-orthorhombic structural transition upon cooling to room temperature, although its origins are uncertain. Here both structures are revisited using a combination of neutron and synchrotron X-ray diffraction data. Large shifts of oxygen positions are detected which show that the interlayer sites and those which occupy voids in the kagome lattice are trivially charge ordered in both phases. The symmetry breaking is found to occur due to Mn3+ orbital ordering on the ribbon sites and charge ordering of the sub-set of layer sites which make up a Kagome network.Comment: Minor changes, to appear in J. Phys. Cond. Mat

    The unintegrated gluon distribution from the CCFM equation

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    The gluon distribution f(x, k_t^2,mu^2), unintegrated over the transverse momentum k_t of the gluon, satisfies the angular-ordered CCFM equation which interlocks the dependence on the scale k_t with the scale \mu of the probe. We show how, to leading logarithmic accuracy, the equation can be simplified to a single scale problem. In particular we demonstrate how to determine the two-scale unintegrated distribution f(x,k_t^2,mu^2) from knowledge of the integrated gluon obtained from a unified scheme embodying both BFKL and DGLAP evolution.Comment: 16 pages LaTeX, 3 eps figure

    Lattice collapse and quenching of magnetism in CaFe2As2 under pressure: A single crystal neutron and x-ray diffraction investigation

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    Single crystal neutron and high-energy x-ray diffraction have identified the phase lines corresponding to transitions between the ambient-pressure tetragonal (T), the antiferromagnetic orthorhombic (O) and the non-magnetic collapsed tetragonal (cT) phases of CaFe2As2. We find no evidence of additional structures for pressures up to 2.5 GPa (at 300 K). Both the T-cT and O-cT transitions exhibit significant hysteresis effects and we demonstrate that coexistence of the O and cT phases can occur if a non-hydrostatic component of pressure is present. Measurements of the magnetic diffraction peaks show no change in the magnetic structure or ordered moment as a function of pressure in the O phase and we find no evidence of magnetic ordering in the cT phase. Band structure calculations show that the transition results in a strong decrease of the iron 3d density of states at the Fermi energy, consistent with a loss of the magnetic moment.Comment: List of authors in metadata and typos in labeling of inset in Fig. 1(a) corrected. One ref. added. No other change

    Charge order at the frontier between the molecular and solid states in Ba3NaRu2O9

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    We show that the valence electrons of Ba3NaRu2O9, which has a quasi-molecular structure, completely crystallize below 210 K. Using an extended Hubbard model, we show that the charge ordering instability results from long-range Coulomb interactions. However, orbital ordering, metal-metal bonding and formation of a partial spin gap enforce the magnitude of the charge separation. The striped charge order and frustrated hcp lattice of Ru2O9 dimers lead to competition with a quasi-degenerate charge-melted phase under photo-excitation at low temperature. Our results establish a broad class of simple metal oxides as models for emergent phenomena at the border between the molecular and solid states.Comment: Minor changes, with supporting information. To appear in Phys. Rev. Let

    Chemical Tuning of Positive and Negative Magnetoresistances, and Superconductivity in 1222-type Ruthenocuprates

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    High critical-temperature superconductivity and large (colossal) magnetoresistances are two important electronic conducting phenomena found in transition metal oxides. High-Tc materials have applications such as superconducting magnets for MRI and NMR, and magnetoresistive materials may find use in magnetic sensors and spintronic devices. Here we report chemical doping studies of RuSr2(R2-xCex)Cu2O10-d ruthenocuprates which show that a single oxide system can be tuned between superconductivity at high hole dopings and varied magnetoresistive properties at low doping levels. A robust variation of negative magnetoresistance with hole concentration is found in the RuSr2R1.8-xY0.2CexCu2O10-d series, while RuSr2R1.1Ce0.9Cu2O10-d materials show an unprecedented crossover from negative to positive magnetoresistance with rare earth (R) ion radius

    E‐cigarette support for smoking cessation: Identifying the effectiveness of intervention components in an on‐line randomized optimization experiment

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    Aims, Design and Setting The aim of this study was to determine which combination(s) of five e-cigarette-orientated intervention components, delivered on-line, affect smoking cessation. An on-line (UK) balanced five-factor (2 × 2 × 2 × 2 × 2 = 32 intervention combinations) randomized factorial design guided by the multi-phase optimization strategy (MOST) was used. Participants A total of 1214 eligible participants (61% female; 97% white) were recruited via social media. Interventions The five on-line intervention components designed to help smokers switch to exclusive e-cigarette use were: (1) tailored device selection advice; (2) tailored e-liquid nicotine strength advice; (3): tailored e-liquid flavour advice; (4) brief information on relative harms; and (5) text message (SMS) support. Measurements The primary outcome was 4-week self-reported complete abstinence at 12 weeks post-randomization. Primary analyses were intention-to-treat (loss to follow-up recorded as smoking). Logistic regressions modelled the three- and two-way interactions and main effects, explored in that order. Findings In the adjusted model the only significant interaction was a two-way interaction, advice on flavour combined with text message support, which increased the odds of abstinence (odds ratio = 1.55, 95% confidence interval = 1.13–2.14, P = 0.007, Bayes factor = 7.25). There were no main effects of the intervention components. Conclusions Text-message support with tailored advice on flavour is a promising intervention combination for smokers using an e-cigarette in a quit attempt

    Impaired Langerhans cell migration in psoriasis

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    We have examined whether psoriasis is associated with systemic effects on epidermal Langerhans cell (LC) function and, specifically, the migration of LCs from the skin. Compared with normal skin, the frequency and morphology of epidermal LCs in uninvolved skin from patients with psoriasis was normal. However, mobilization of these cells in response to stimuli that normally induce migration (chemical allergen, tumor necrosis factor α [TNF-α], and interleukin-1β [IL-1β]) was largely absent, despite the fact that treatment with TNF-α and IL-1β was associated with comparable inflammatory reactions in patients and controls. The failure of LC migration from uninvolved skin was not attributable to altered expression of receptors for IL-1β or TNF-α that are required for mobilization, nor was there an association with induced cutaneous cytokine expression. Although a role for altered dynamics of LC migration/turnover has not been formally excluded, these data reveal a very consistent decrement of LC function in psoriasis that may play a decisive role in disease pathogenesis
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