Leydig Cell Tumour and Mature Ovarian Teratoma: Rare Androgen-Secreting Ovarian Tumours in Postmenopausal Women

Androgen-secreting ovarian tumours are extremely rare accounting for <5% of all ovarian neoplasms. They are more frequent in postmenopausal women and should be suspected in the case of a rapid onset of androgenic symptoms. We report 4 cases of postmenopausal women who presented with signs of virilisation. All patients revealed increased serum levels of testosterone, normal dehydroepiandrosterone-sulfate and negative pelvic ultrasound for adnexal masses. An androgen-secreting ovarian tumour was suspected and all of them were submitted to bilateral oophorectomy. Histology confirmed the diagnosis of Leydig cell tumours in 3 patients and mature teratoma in 1. A successful response to surgery, which includes a decline in serum androgen levels and signs of hyperandrogenism, was observed in our patients. This case series demonstrates that androgen-secreting ovarian neoplasms may not be detectable by imaging studies, but should be considered in the differential diagnosis of all postmenopausal women with signs of hyperandrogenism.info:eu-repo/semantics/publishedVersio

Micro-Switches with Sputtered Au, AuPd, Au-on-AuPt, and AuPtCu Alloy Electric Contacts

This work is the first to report on a new analytic model for predicting micro-contact resistance and the design, fabrication, and testing of microelectromechanical systems (MEMS) metal contact switches with sputtered bi-metallic (i.e. gold (Au)-on-Au-platinum (Pt), (Au-on-Au-(6%)Pt)), binary alloy (i.e. Au-palladium (Pd), (Au-(2%)Pd)), and tertiary alloy (i.e. Au-Pt-copper (Cu), (Au-(5%)Pt-(0.5%)Cu)) electric contacts. The micro-switches with bi-metallic and binary alloy contacts resulted in contact resistance between 1-2 /spl Omega/ and, when compared to micro-switches with sputtered Au electric contacts, exhibited a 3.3 and 2.6 times increase in switching lifetime, respectively. The tertiary alloy exhibited a 6.5 times increase in switch lifetime with contact resistance ranging from 0.2-1.8 /spl Omega/

Screening in Anyon Gas

Anyon gas with interparticle (retarded) Coulomb interaction has been studied. The resulting system is shown to be a collection of dressed anyons, with a screening factor introduced in their spin. Close structural similarity with the Chern-Simons construction of anyons has helped considerably in computing the screening effect. Finally the present model is compared with the conventional Chern-Simons construction.Comment: 10 pages Late

Myxedema Coma

Os AA. apresentam 5 casos de coma mixedematoso observados no período de 1984 a 1992. Trata-se de 4 doentes do sexo feminino e 1 do sexo masculino com idades compreendidas entre os 45 e 73 anos. Em 3 doentes não havia diagnóstico prévio de hipotiroidismo. A depressão do estado de consciência, a hipotermia, a bradicardia e a ausência de bócio eram comuns aos 5 doentes. Foi identificado factor desencadeante em 3 deles. Utilizada levotiroxina e/ou liotironina por via oral, hidrocortisona e medidas de suporte, a evolução foi favorável nos 2 doentes em que tinha sido identificado factor desencadeante, que apresentavam menor depressão do S.N.C. e normalização da temperatura corporal ao 3° dia de terapêutica

Myxedema Coma

Os AA. apresentam 5 casos de coma mixedematoso observados no período de 1984 a 1992. Trata-se de 4 doentes do sexo feminino e 1 do sexo masculino com idades compreendidas entre os 45 e 73 anos. Em 3 doentes não havia diagnóstico prévio de hipotiroidismo. A depressão do estado de consciência, a hipotermia, a bradicardia e a ausência de bócio eram comuns aos 5 doentes. Foi identificado factor desencadeante em 3 deles. Utilizada levotiroxina e/ou liotironina por via oral, hidrocortisona e medidas de suporte, a evolução foi favorável nos 2 doentes em que tinha sido identificado factor desencadeante, que apresentavam menor depressão do S.N.C. e normalização da temperatura corporal ao 3° dia de terapêutica

Teaching meiosis with the DNA triangle framework: A classroom activity that changes how students think about chromosomes

Many biology students struggle to learn about the process of meiosis and have particular difficulty understanding the molecular basis of crossing over and the importance of homologous pairing for proper segregation. To help students overcome these challenges, we designed an activity that uses a newly developed Chromosome Connections Kit® from 3-D Molecular Designs to allow learners to explore meiosis at the molecular level. We took a backwards design approach in constructing an effective classroom activity. We developed evidence-based learning objectives and designed a crossing over activity that targets students\u27 misconceptions and key concepts about meiosis. Assessment questions were designed based on the learning objectives and common student misconceptions. The activity consists of three parts: an interactive introductory video, a model-based activity, and reflection questions. The activity was first beta-tested with a small number of students and revised based on feedback. The revised activity was deployed in a mid-level Cell and Molecular Biology course. Analysis of pre-/post-assessment data from students who completed the activity (n = 83) showed strong learning gains on concepts related to ploidy, homology, segregation, and the mechanism and purpose of crossing over. Additionally, students who participated in the activity outperformed nonparticipants on a Genetics assessment about meiosis the following semester

Electron and Hole Spin Splitting and Photogalvanic Effect in Quantum Wells

A theory of the circular photogalvanic effect caused by spin splitting in quantum wells is developed. Direct interband transitions between the hole and electron size-quantized subbands are considered. It is shown that the photocurrent value and direction depend strongly on the form of the spin-orbit interaction. The currents induced by structure-, bulk-, and interface-inversion asymmetry are investigated. The photocurrent excitation spectra caused by spin splittings in both conduction and valence bands are calculated.Comment: 7 pages, 3 figure

Decoherence times of universal two-qubit gates in the presence of broad-band noise

The controlled generation of entangled states of two quantum bits is a fundamental step toward the implementation of a quantum information processor. In nano-devices this operation is counteracted by the solid-state environment, characterized by a broadband and non-monotonic power spectrum, often 1/f at low frequencies. For single-qubit gates, incoherent processes due to fluctuations acting on different time scales result in peculiar short- and long-time behavior. Markovian noise gives rise to exponential decay with relaxation and decoherence times, T1 and T2, simply related to the symmetry of the qubit-environment coupling Hamiltonian. Noise with the 1/f power spectrum at low frequencies is instead responsible for defocusing processes and algebraic short-time behavior. In this paper, we identify the relevant decoherence times of an entangling operation due to the different decoherence channels originating from solid-state noise. Entanglement is quantified by concurrence, which we evaluate in an analytic form employing a multi-stage approach. The 'optimal' operating conditions of reduced sensitivity to noise sources are identified. We apply this analysis to a superconducting \sqrt{i-SWAP} gate for experimental noise spectra.Comment: 35 pages, 11 figure

Kaposi's sarcoma with a non-Hodgkin's lymphoma. Its association in a male homosexual with human T-cell lymphotropic virus type III infection

Combined tumor syndromes, specifically reticuloendothelial malignancies and Kaposi’s sarcoma, have long been recognized. With the recognition of the acquired immunodeficiency syndrome (AIDS), several patients with concurrent non-Hodgkin’s lymphoma and Kaposi’s sarcoma have been reported at high risk for developing AIDS. The present Centers for Disease Control definition of AIDS excludes these patients on the assumption that one tumor is affecting the cellular immunity, allowing for the development of the second malignancy. In evaluating such a patient who had serologic evidence of human T-cell lymphotropic virus type III infection, the probable cause of AIDS, we have reviewed reports of patients with similar concurrent malignancies before and since the onset of the AIDS epidemic. We conclude that patients in high-risk groups for AIDS who develop similar combined tumor syndromes should be classified as having AIDS

Studies in homosexual patients with and without lymphadenopathy - Relationships to the acquired immune deficiency syndrome

We studied the immunologic function of 19 sexually active homosexual men, ten of whom had persistent lymphadenopathy. Analysis of mononuclear cell populations distinguished homosexuals from heterosexual controls since, as a group, homosexuals had increased percentages of natural killer cells (Leu 7+), decreased helper-inducer T lymphocytes (OKT-4+), increased suppressor/cytotoxic (OKT-8+) T lymphocytes, low OKT-4:OKT-8 ratios, and depressed mitogenic responses. Homosexuals without lymphadenopathy were distinguishable from controls by increased percentages of la+ cells, decreased OKT-4+ cells, and decreased OKT-4:OKT-8 ratios. Four had positive findings simultaneously for hepatitis B surface antigen (HBsAg) and surface antibody, and five had positive findings for HBsAg alone. Homosexuals with lymphadenopathy were distinguishable from controls by increased percentages of Leu 7+ cells, increased total lymphocyte numbers per cubic millimeter, decreased percentages of both OKT-4+ and OKT-8+ cells, abnormal OKT-4:OKT-8 ratios, and depressed mitogenic responses. Only histories of larger numbers of sexually acquired diseases, higher numbers of OKT-8+ cells per cubic millimeter, and lower mitogenic responses in homosexuals with lymphadenopathy distinguished this group from homosexuals without lymphadenopathy. Furthermore, none of the nine patients tested in this group was HBsAg positive. We conclude that homosexuals without lymphadenopathy are distinguishable from those with lymphadenopathy by both immunologic and serologic abnormalities