Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 83
Filtrar
1.
Int J STD AIDS ; 35(7): 569-570, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38456826

RESUMO

We report the case of a young man who has never had any sexual contact presenting with a large scrotal lump with secondary bacterial infection. He reported no prior warts - genital or cutaneous. On examination, he had a large pink cauliform mass on the scrotum with four smaller but similar satellite lesions. Appearances were thought to be consistent with giant condyloma of Buschke and Lowenstein. Once superinfection was treated with oral antibiotics, he had a trial of imiquimod without success and was then referred to urology. After surgical excision, pathology concluded it was an inflamed fibroepithelial polyp with no malignant changes. To our knowledge, this is the first case report of a giant scrotal fibroepithelial polyp with characteristic gross warty features in an adult.


Assuntos
Condiloma Acuminado , Pólipos , Escroto , Humanos , Masculino , Escroto/patologia , Pólipos/diagnóstico , Pólipos/patologia , Pólipos/cirurgia , Condiloma Acuminado/diagnóstico , Condiloma Acuminado/patologia , Condiloma Acuminado/cirurgia , Diagnóstico Diferencial , Adulto , Neoplasias Fibroepiteliais/diagnóstico , Neoplasias Fibroepiteliais/patologia , Neoplasias Fibroepiteliais/cirurgia , Resultado do Tratamento
5.
Proc Natl Acad Sci U S A ; 119(38): e2208814119, 2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-36095186

RESUMO

Ureilite meteorites are arguably our only large suite of samples from the mantle of a dwarf planet and typically contain greater abundances of diamond than any known rock. Some also contain lonsdaleite, which may be harder than diamond. Here, we use electron microscopy to map the relative distribution of coexisting lonsdaleite, diamond, and graphite in ureilites. These maps show that lonsdaleite tends to occur as polycrystalline grains, sometimes with distinctive fold morphologies, partially replaced by diamond + graphite in rims and cross-cutting veins. These observations provide strong evidence for how the carbon phases formed in ureilites, which, despite much conjecture and seemingly conflicting observations, has not been resolved. We suggest that lonsdaleite formed by pseudomorphic replacement of primary graphite shapes, facilitated by a supercritical C-H-O-S fluid during rapid decompression and cooling. Diamond + graphite formed after lonsdaleite via ongoing reaction with C-H-O-S gas. This graphite > lonsdaleite > diamond + graphite formation process is akin to industrial chemical vapor deposition but operates at higher pressure (∼1-100 bar) and provides a pathway toward manufacture of shaped lonsdaleite for industrial application. It also provides a unique model for ureilites that can reconcile all conflicting observations relating to diamond formation.

6.
Int J STD AIDS ; 33(12): 1078-1083, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36120911

RESUMO

BACKGROUND: New late HIV diagnosis (CD4 count <350cells/mm3) are higher in North West England compared to the UK average. A Greater Manchester-wide audit into individuals diagnosed with late or very late HIV was conducted in 2016 and re-audited in 2019. Our aim was to gain intelligence into key demographics of late diagnosed individuals across Greater Manchester, review opportunities for earlier diagnosis and determine if key recommendations from the 2016 audit were followed. METHODS: Individuals were identified from locally kept data or HIV and AIDS Reporting System (HARS) data. A retrospective case note review was performed for each patient using data from local notes, General Practice summary of care records and relevant clinical letters. Data was collected for 2019 and compared to 2016 results. RESULTS: In 2016, nine departments contributed data and 104 individuals were identified as having been diagnosed late. In 2019, seven departments contributed data and 65 individuals were identified as having been diagnosed late. In both years, a greater proportion of males diagnosed late were White British and for females Black African. A greater proportion of late diagnosis occurred in men who have sex with men (MSM) and in heterosexual females. In 2019, a greater proportion of patients had an AIDS-defining illness at time of diagnosis. Whilst in 2016, most patients were asymptomatic. Over one third of patients had a clinical indicator disease in their past medical history, which is an increase in proportion from 2016. The proportion of cases where clinicians felt that there had been probable missed opportunities for earlier diagnosis also increased in 2019. CONCLUSIONS: There are continued missed opportunities for earlier diagnosis. We recommend targeted interventions for groups at higher risk of late presentation, education in primary/secondary care regarding clinical indicator conditions, a formal review process for all late diagnosed cases, communication with primary/secondary care if missed opportunities are identified and broader HIV testing especially in high prevalence areas.


Assuntos
Infecções por HIV , Minorias Sexuais e de Gênero , Masculino , Feminino , Humanos , Diagnóstico Tardio , Homossexualidade Masculina , Estudos Retrospectivos , Infecções por HIV/diagnóstico , Infecções por HIV/epidemiologia , Infecções por HIV/complicações , Contagem de Linfócito CD4 , Fatores de Risco
7.
Proc Natl Acad Sci U S A ; 119(31): e2202116119, 2022 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-35901210

RESUMO

A/B testing is widely used to tune search and recommendation algorithms, to compare product variants as efficiently and effectively as possible, and even to study animal behavior. With ongoing investment, due to diminishing returns, the items produced by the new alternative B show smaller and smaller improvement in quality from the items produced by the current system A. By formalizing this observation, we develop closed-form analytical expressions for the sample efficiency of a number of widely used families of slate-based comparison tests. In empirical trials, these theoretical sample complexity results are shown to be predictive of real-world testing efficiency outcomes. These findings offer opportunities for both more cost-effective testing and a better analytical understanding of the problem.

8.
Adv Nutr ; 13(3): 970-972, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35641237
9.
Astrobiology ; 22(4): 399-415, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35100042

RESUMO

Meteorites that fall to Earth quickly become contaminated with terrestrial microorganisms. These meteorites are out of chemical equilibrium in the environments where they fall, and equilibration promotes formation of low-temperature alteration minerals that can entomb contaminant microorganisms and thus preserve them as microfossils. Given the well-understood chemistry of meteorites and their recent discovery on Mars by rovers, a similarly weathered meteorite on Mars could preserve organic and fossil evidence of a putative past biosphere at the martian surface. Here, we used several techniques to assess the potential of alteration minerals to preserve microfossils and biogenic organics in terrestrially weathered ordinary chondrites from the Nullarbor Plain, Australia. We used acid etching of ordinary chondrites to reveal entombed fungal hyphae, modern biofilms, and diatoms within alteration minerals. We employed synchrotron X-ray fluorescence microscopy of alteration mineral veins to map the distribution of redox-sensitive elements of relevance to chemolithotrophic organisms, such as Mn-cycling bacteria. We assessed the biogenicity of fungal hyphae within alteration veins using a combination of Fourier-transform infrared spectroscopy and pyrolysis gas chromatography-mass spectrometry, which showed that alteration minerals sequester and preserve organic molecules at various levels of decomposition. Our combined analyses results show that fossil microorganisms and the organic molecules they produce are preserved within calcite-gypsum admixtures in meteorites. Furthermore, the distributions of redox-sensitive elements (e.g., Mn) within alteration minerals are localized, which qualitatively suggests that climatically or microbially facilitated element mobilization occurred during the meteorite's residency on Earth. If returned as part of a sample suite from the martian surface, ordinary chondrites could preserve similar, recognizable evidence of putative past life and/or environmental change.


Assuntos
Marte , Meteoroides , Planeta Terra , Exobiologia/métodos , Meio Ambiente Extraterreno , Minerais/análise
10.
Nat Commun ; 12(1): 1388, 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33654089

RESUMO

Reaction-induced porosity is a key factor enabling protracted fluid-rock interactions in the Earth's crust, promoting large-scale mineralogical changes during diagenesis, metamorphism, and ore formation. Here, we show experimentally that the presence of trace amounts of dissolved cerium increases the porosity of hematite (Fe2O3) formed via fluid-induced, redox-independent replacement of magnetite (Fe3O4), thereby increasing the efficiency of coupled magnetite replacement, fluid flow, and element mass transfer. Cerium acts as a catalyst affecting the nucleation and growth of hematite by modifying the Fe2+(aq)/Fe3+(aq) ratio at the reaction interface. Our results demonstrate that trace elements can enhance fluid-mediated mineral replacement reactions, ultimately controlling the kinetics, texture, and composition of fluid-mineral systems. Applied to some of the world's most valuable orebodies, these results provide new insights into how early formation of extensive magnetite alteration may have preconditioned these ore systems for later enhanced metal accumulation, contributing to their sizes and metal endowment.

11.
Astrobiology ; 20(3): 364-374, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31873039

RESUMO

The advent of microfluidics has revolutionized the way we understand how microorganisms propagate through microporous spaces. Here, we apply this understanding to the study of how endolithic environmental microorganisms colonize the interiors of sterile rock. The substrates used for our study are stony meteorites from the Nullarbor Plain, Australia; a semiarid limestone karst that provides an ideal setting for preserving meteorites. Periodic flooding of the Nullarbor provides a mechanism by which microorganisms and exogenous nutrients may infiltrate meteorites. Our laboratory experiments show that environmental microorganisms reach depths greater than 400 µm by propagating through existing brecciation, passing through cracks no wider than the diameter of a resident cell (i.e., ∼5 µm). Our observations are consistent with the propagation of these eukaryotic cells via growth and cell division rather than motility. The morphology of the microorganisms changed as a result of propagation through micrometer-scale cracks, as has been observed previously for bacteria on microfluidic chips. It has been suggested that meteorites could have served as preferred habitats for microorganisms on ancient Mars. Based on our results, the depths reached by terrestrial microorganisms within meteorites would be sufficient to mitigate against the harmful effects of ionizing radiation, such as UV light, in Earth's deserts and potentially on Mars, if similar processes of microbial colonization had once been active there. Thus, meteorites landing in ancient lakes on Mars, that later dried out, could have been some of the last inhabited locations on the surface, serving as refugia before the planet's surface became inhospitable. Finally, our observations suggest that terrestrial microorganisms can colonize very fine cracks within meteorites (and potentially spaceships and rovers) on unexpectedly short timescales, with important implications for both recognition of extraterrestrial life in returned geological samples and planetary protection.


Assuntos
Eucariotos/isolamento & purificação , Exobiologia/métodos , Meio Ambiente Extraterreno/química , Meteoroides , Técnicas Analíticas Microfluídicas , Austrália , Carbonato de Cálcio/química , Marte , Porosidade , Propriedades de Superfície
12.
Perspect Public Health ; 139(1): 23-33, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29846139

RESUMO

AIMS:: Sexualised drug taking is increasingly reported on national and international levels. We aim to review existing evidence of the relationship between recreational drug use (RDU) and sexual intercourse among men who have sex with men (MSM). METHODS:: We reviewed published abstracts and full articles identified from Cochrane, MEDLINE and Embase databases from November 2010 to 2017. We included any existing studies investigating RDU in MSM and at least one of the following: high-risk sexual practices, sexually transmitted infections (STIs) or barriers to accessing specialist support. RESULTS:: In total, 112 studies were included. Of them, 38 studies specifically reported the prevalence of chemsex-related drug use. Links with sexualised drug taking and high-risk sexual practices including condomless sex and group sex were reported by several studies. Recreational drug use in the sexual setting appears linked to the acquisition of STIs, including hepatitis C, syphilis and gonorrhoea. Reports of adverse mental health outcomes are increasingly described, with several studies documenting chemsex-related inpatient admission. A paucity of research addressing barriers to those accessing specialist drug support services was identified. CONCLUSION:: This review demonstrates the complex interplay between recreational drug use, high-risk sexual practices and STIs. It identifies the description of adverse mental health outcomes in the chemsex setting, thus highlighting the need for a multidisciplinary approach across specialties in the management of those adversely affected. Finally, it illuminates the need for future research into perceived barriers of those who require access to support services to ensure timely and comprehensive support provision.


Assuntos
Homossexualidade Masculina , Comportamento Sexual/estatística & dados numéricos , Transtornos Relacionados ao Uso de Substâncias , Infecções por HIV/transmissão , Hepatite C/transmissão , Homossexualidade Masculina/psicologia , Humanos , Masculino , Infecções Sexualmente Transmissíveis/transmissão , Sexo sem Proteção/estatística & dados numéricos
13.
Int J STD AIDS ; 30(2): 201-203, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30348066

RESUMO

Did not attend (DNA) appointments create a significant impact upon resource and finance efficiency in the NHS. Despite introduction of short-message service (SMS) reminders to our patients, DNA rates remained persistently high. An option to send an SMS to cancel a booked appointment was piloted from 15 January to 16 April 2018 for integrated sexual health and human immunodeficiency virus (HIV) appointments. Absolute monthly mean DNA rates as a proportion of total bookable appointments fell by 2.24% (14.42% pre-intervention [95% CI: 13.15-15.79%] to 12.18% post-intervention [95% CI: 10.98-13.50%]). Cancellation rates increased proportionally by 14.28% from 24.4% to 38.68% (786/3224 pre-intervention [95% CI: 22.70%-26.15%] to 1184/3061 post-intervention [95% CI: 36.52-40.93%]). Findings suggest that SMS cancellations are a viable solution to reduce DNA rates in this setting.


Assuntos
Agendamento de Consultas , Visita a Consultório Médico/estatística & dados numéricos , Cooperação do Paciente/estatística & dados numéricos , Sistemas de Alerta , Envio de Mensagens de Texto , Telefone Celular , Prestação Integrada de Cuidados de Saúde , Feminino , Humanos , Masculino , Prontuários Médicos , Saúde Sexual
14.
Sci Rep ; 8(1): 16411, 2018 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-30401916

RESUMO

Changes in the oxygen fugacity (fO2) of the Earth's mantle have been proposed to control the spatial and temporal distribution of arc-related ore deposits, and possibly reflect the evolution of the atmosphere over billions of years. Thermodynamic calculations and natural evidence indicate that fluids released from subducting slabs can oxidise the mantle, but whether their oxidation potential varied in space and time remains controversial. Here, we use garnet peridotites from western Norway to show that there is a linear decrease in maximum fO2 with increasing depth in the mantle wedge. We ascribe this relation to changes in the speciation of sulfur released in slab fluids, with sulfate, controlling maximum oxidation, preferentially released at shallow depths. Even though the amount of sulfate in the Precambrian oceans, and thus in subducted lithologies, is thought to have been dramatically lower than during the Phanerozoic, garnet peridotites metasomatised during these two periods have a comparable fO2 range. This opens to the possibility that an oxidised mantle with fO2 similar to modern-day values has existed since the Proterozoic and possibly earlier. Consequently, early magmas derived from partial melting of metasomatised mantle may have had suitable fO2 to generate porphyry Cu-Au and iron-oxide Cu-Au deposits.

15.
Int J STD AIDS ; 29(13): 1351-1353, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30049255
17.
Int J STD AIDS ; 29(2): 128-134, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28691863

RESUMO

Reports of sexualised drug taking (chemsex) have increased significantly in recent years. There is currently limited intelligence on chemsex outside of London. An anonymous survey was promoted via several sources including voluntary services and a sexual health clinic in order to establish the risks associated with chemsex, and how support services can best be tailored to meet the needs of those in Greater Manchester, UK. Quantitative and qualitative data were collected on demographics, drug use, sexual practices and barriers and facilitators to accessing support. Fifty-two men who have sex with men completed the online survey. Thirty-nine (75%) were HIV-positive and 11 (21%) were hepatitis C virus (HCV) positive, all of whom were HIV/HCV co-infected. The most commonly used drugs were mephedrone (81%) and gamma hydroxybutyrate/gamma butyrolactone (79%). Nineteen (37%) reported ever injecting drugs. High-risk sexual practices were reported by respondents. Barriers to accessing support included a fear of being recognised. Findings demonstrate those engaging in chemsex are participating in a number of high-risk sexual practices, taking substances with significant risks and administering these substances in potentially high-risk ways. Results demonstrate the need for promotion of existing services, with key areas to target where chemsex sessions are most commonly arranged. Results may be useful in other metropolitan cities, both for commissioning and tailoring of chemsex support services.


Assuntos
4-Butirolactona/administração & dosagem , Infecções por HIV/epidemiologia , Hepatite C/epidemiologia , Homossexualidade Masculina/psicologia , Internet , Metanfetamina/análogos & derivados , Comportamento Sexual/efeitos dos fármacos , Oxibato de Sódio/administração & dosagem , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , 4-Butirolactona/efeitos adversos , Adulto , Coinfecção/epidemiologia , Infecções por HIV/diagnóstico , Redução do Dano , Humanos , Londres/epidemiologia , Masculino , Metanfetamina/administração & dosagem , Metanfetamina/efeitos adversos , Pessoa de Meia-Idade , Assunção de Riscos , Parceiros Sexuais , Oxibato de Sódio/efeitos adversos , Inquéritos e Questionários , Sexo sem Proteção , Adulto Jovem
18.
Sex Transm Infect ; 94(5): 337-339, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28196838

RESUMO

OBJECTIVE: To determine the prevalence of asymptomatic neurosyphilis (ANS) in HIV-positive individuals after treatment of early syphilis with single-dose benzathine penicillin G (BPG) or oral antibiotic alternatives. METHODS: Patients at high risk of neurosyphilis (defined by serum rapid plasma reagin (RPR) titre ≥1:32 and/or peripheral blood CD4 lymphocyte count ≤350/µL) underwent lumbar puncture (LP) at a median time of 8.2 months post treatment. ANS was diagnosed by a reactive cerebrospinal fluid (CSF) RPR test or CSF white blood cells (WBC) >20/µL plus a reactive CSF Treponema pallidum particle agglutination (TPPA) ≥1:640. RESULTS: Of 133 eligible patients, all were men who have sex with men. Of these, 64 consented to LP. Full CSF results were available for 59 patients. Inclusion criteria were serum RPR (21/59), CD4 count (22/59) and combined RPR and CD4 (16/59). The LP patients were white British (82%), median age 40. Syphilis stages were primary (17%) secondary (43%) and early latent (41%). Syphilis was treated with BPG (47/59), doxycycline 100 mg two times per day for 14 days (10/59) and for 21 days (1/59). Azithromycin 500 mg one time per day for 10 days was given to 1/59. At the time of LP, 100% of patients had achieved serological cure, and 66% were taking antiretroviral treatment. Only 1/59 was diagnosed with ANS. The CSF showed: RPR non-reactive (59/59); TPPA non-reactive in 54/59; WBC ≤5/µL in 51/59. CONCLUSIONS: Although the number of patients in our study is modest, single-dose BPG appears to be highly effective even in patients at high risk of neurosyphilis.


Assuntos
Infecções Assintomáticas/epidemiologia , Infecções por HIV/complicações , Neurossífilis/diagnóstico , Sífilis/tratamento farmacológico , Adulto , Antibacterianos/uso terapêutico , Infecções Assintomáticas/terapia , Contagem de Linfócito CD4 , Inglaterra/epidemiologia , Infecções por HIV/epidemiologia , Infecções por HIV/microbiologia , Homossexualidade Masculina , Humanos , Masculino , Neurossífilis/líquido cefalorraquidiano , Neurossífilis/epidemiologia , Neurossífilis/microbiologia , Penicilina G Benzatina/uso terapêutico , Prevalência , Fatores de Risco , Sífilis/complicações , Sífilis/microbiologia , Sorodiagnóstico da Sífilis , Treponema pallidum/imunologia
20.
Proc Natl Acad Sci U S A ; 114(48): 12708-12713, 2017 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-29138317

RESUMO

Peer review may be "single-blind," in which reviewers are aware of the names and affiliations of paper authors, or "double-blind," in which this information is hidden. Noting that computer science research often appears first or exclusively in peer-reviewed conferences rather than journals, we study these two reviewing models in the context of the 10th Association for Computing Machinery International Conference on Web Search and Data Mining, a highly selective venue (15.6% acceptance rate) in which expert committee members review full-length submissions for acceptance. We present a controlled experiment in which four committee members review each paper. Two of these four reviewers are drawn from a pool of committee members with access to author information; the other two are drawn from a disjoint pool without such access. This information asymmetry persists through the process of bidding for papers, reviewing papers, and entering scores. Reviewers in the single-blind condition typically bid for 22% fewer papers and preferentially bid for papers from top universities and companies. Once papers are allocated to reviewers, single-blind reviewers are significantly more likely than their double-blind counterparts to recommend for acceptance papers from famous authors, top universities, and top companies. The estimated odds multipliers are tangible, at 1.63, 1.58, and 2.10, respectively.


Assuntos
Modelos Estatísticos , Revisão da Pesquisa por Pares/métodos , Viés de Publicação/tendências , Autoria , Método Duplo-Cego , Políticas Editoriais , Feminino , Humanos , Masculino , Revisão da Pesquisa por Pares/ética , Método Simples-Cego
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA