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1.
S Afr Med J ; 111(10): 950-956, 2021 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-34949288

RESUMO

BACKGROUND: The phenomenon of silent hypoxaemia has been described in patients with COVID-19 pneumonia, which is characterised by low oxygen saturation levels of <90% in those who appear clinically well and do not show signs of significant respiratory distress. OBJECTIVES: To assess the impact on clinical outcomes for high-risk COVID-19 patients using a pulse oximeter to monitor oxygen saturation levels in a home setting. METHODS: We performed a retrospective cohort analysis using data from a large South African insurance administrator. Patients were categorised as high risk, based on age and specific underlying clinical conditions, or from predictive models derived from medical scheme administrative claims data. The impact of pulse oximetry home monitoring on COVID-19 clinical outcomes was investigated by the use of Cox proportional hazard models. RESULTS: Between 2 March 2020 and 31 October 2020, of 38 660 patients analysed, 8 115 were in the intervention group. The 60-day mortality rate for the evaluated high-risk population was 1.35%. After adjusting for age and comorbidity differences, the intervention group was found to have an adjusted hazard ratio of 0.52 (p<0.0001). No statistical significance was found between the intervened and control groups for admission to hospital, admission to intensive care unit (ICU) and use of mechanical ventilation. The intervention group had a lower median C-reactive protein (CRP) level on admission (p=0.03). After adjustment for admission CRP levels, elevated CRP was associated with an increased mortality (p<0.0001), while the statistical significance in mortality between the intervention and the control group was lost. CONCLUSIONS: High-risk COVID-19 patients who used a pulse oximeter to monitor oxygen saturation levels had significantly lower mortality rates compared with other high-risk patients. The mortality benefit may be explained by earlier presentation to hospital, as suggested by lower initial CRP levels.


Assuntos
COVID-19/fisiopatologia , Hospitalização/estatística & dados numéricos , Oximetria/métodos , Saturação de Oxigênio , Adulto , Proteína C-Reativa/metabolismo , COVID-19/mortalidade , Estudos de Coortes , Feminino , Humanos , Unidades de Terapia Intensiva/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Respiração Artificial/estatística & dados numéricos , Estudos Retrospectivos , Índice de Gravidade de Doença , África do Sul
2.
J Phys Condens Matter ; 32(37): 374013, 2020 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-32289761

RESUMO

The compound La2-2x Sr1+2x Mn2O7, x = 0.30-0.40, consists of bilayers of ferromagnetic metallic MnO2 sheets that are separated by insulating layers. The materials show colossal magnetoresistance-a reduction in resistivity of up to two orders of magnitude in a field of 7 T-at their three-dimensional ordering temperatures, T C = 90-126 K, and are the layered analogues of the widely studied pseudo-cubic perovskite manganites, R1-x A x MnO3 (R = rare earth, A = Ca, Sr, Ba, Pb). Two distinct short-range orderings-antiferromagnetic fluctuations and correlated polarons, which are related to the magnetic and the lattice degrees of freedom respectively-have previously been discovered in La2-2x Sr1+2x Mn2O7, x = 0.40, and have each been qualitatively connected to the resistivity. Here, in a comprehensive study as a function of both temperature and magnetic field for the different hole-concentrations per Mn site of x = 0.30 and 0.35, we show that antiferromagnetic fluctuations also appear at temperatures just above T C, and that the intensities of both the antiferromagnetic fluctuations and polaron correlations closely track the resistivity. In particular, for x = 0.35 we show that there is a simple scaling relation between the intensities of the antiferromagnetic fluctuations and the in-plane resistivity that applies for the temperatures and magnetic fields used in the experiments. The results show that antiferromagnetic fluctuations are a common feature of La2-2x Sr1+2x Mn2O7 with ferromagnetic bilayers, and that there is a close connection between the antiferromagnetic fluctuations and polarons in these materials.

3.
Res Rep Health Eff Inst ; (197): 1-57, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-31872749

RESUMO

INTRODUCTION: Many studies have established associations between exposure to air pollution, or atmospheric particulate matter (PM), and adverse health effects. An increasing array of studies have suggested oxidative stress as a possible mechanism by which PM-induced health effects arise, and as a result, many chemical and cellular assays have been developed to study PM-induced oxidant production. Although significant progress has been made in recent years, there are still many gaps in this area of research that have not been addressed. Many prior studies have focused on the aerosol of primary origin (e.g., the aerosol emitted from combustion engines) although the aerosol formed from the oxidation of volatile species, secondary organic aerosol (SOA), has been shown to be the predominant type of aerosol even in urban areas. Current SOA health studies are limited in number, and as such, the health effects of SOA are poorly characterized. Also, there is a lack of perspective in terms of the relative toxicities of different SOA systems. Additionally, although chemical assays have identified some SOA constituents associated with adverse health endpoints, the applicability of these results to cellular responses has not been well established. SPECIFIC AIMS: The overall objective of this study was to better understand the oxidative properties of different types and components of PM mixtures (especially SOA) through systematic laboratory chamber experiments and ambient field studies. The study had four specific aims.1 To develop a cellular assay optimized for measuring reactive oxygen and nitrogen species (ROS/RNS) production resulting from PM exposure and to identify a robust parameter that could represent ROS/RNS levels for comparison with different endpoints.2 To identify ambient PM components associated with ROS/RNS production and evaluate whether results from chemical assays represented cellular responses in terms of ROS/RNS production.3 To investigate and provide perspective on the relative toxicities of SOA formed from common biogenic and anthropogenic precursors under different conditions (e.g., humidity, nitrogen oxides [NOx], and redox-active metals) and identify bulk aerosol properties associated with cellular responses.4 To investigate the effects of photochemical aging on aerosol toxicity. METHODS: Ambient PM samples were collected from urban and rural sites in the greater Atlanta area as part of the Southeastern Center for Air Pollution and Epidemiology (SCAPE) study between June 2012 and October 2013. The concentrations of water-soluble species (e.g., water-soluble organic carbon [WSOC], brown carbon [Br C], and metals) were characterized using a variety of instruments. Samples for this study were chosen to span the observed range of dithiothreitol (DTT) activities.Laboratory studies were conducted in the Georgia Tech Environmental Chamber (GTEC) facility in order to generate SOA under well-controlled photooxidation conditions. Precursors of biogenic origin (isoprene, α-pinene, and ß-caryophyllene) and anthropogenic origin (pentadecane, m-xylene, and naphthalene) were oxidized under various formation conditions (dry vs. humid, NOx, and ammonium sulfate vs. iron sulfate seed particles) to produce SOA of differing chemical composition and mass loading. For the naphthalene system, a series of experiments were conducted with different initial hydrocarbon concentrations to produce aerosols with various degree of oxidation. A suite of instruments was utilized to monitor gas- and particle-phase species. Bulk aerosol properties (e.g., O:C, H:C, and N:C ratios) were measured using a high-resolution time-of-flight aerosol mass spectrometer. Filter samples were collected for chemical oxidative potential and cellular measurements. For the naphthalene system, multiple filter samples were collected over the course of a single experiment to collect aerosols of different photochemical aging.For all filter samples, chemical oxidative potentials were determined for water-soluble extracts using a semiautomated DTT assay system. Murine alveolar macrophages and neonatal rat ventricular myocytes were also exposed to PM samples extracted in cell culture medium to investigate cellular responses. ROS/RNS production was detected using the intracellular ROS/RNS probe, carboxy-2',7'-dichlorodihydrofluorescein diacetate (carboxy-H2DCFA), whereas cellular metabolic activity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Finally, cytokine production, that is, secreted levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), were measured post-exposure using an enzyme-linked immunosorbent assay (ELISA). To identify PM constituents associated with oxidative properties, linear regressions between oxidative properties (cellular responses or DTT activity) and aerosol composition (metals, elemental ratios, etc.) were evaluated using Pearson's correlation coefficient, where the significance was determined using multiple imputation and evaluated using a 95% confidence interval. RESULTS: We optimized several parameters for the ROS/RNS assay, including cell density (2 × 104 cells/well for macrophages and 3.33 × 104 cells/well for cardiomyocytes), probe concentration (10 µM), and sample incubation time (24 hours). Results from both ambient and laboratory-generated aerosols demonstrate that ROS/RNS production was highly dose-dependent and nonlinear with respect to PM dose. Of the dose-response metrics investigated in this study (maximum response, dose at which the response is 10% above the baseline [threshold], dose at which 50% of the response is attained [EC50], rate at which the maximum response is attained [Hill slope], and area under the dose-response curve [AUC]), we found that the AUC was the most robust parameter whose informativeness did not depend on dose range.A positive, significant correlation was observed between ROS/RNS production as represented by AUC and chemical oxidative potential as measured by DTT for ambient samples collected in summer. Conversely, a relatively constant AUC was observed for ambient samples collected in winter regardless of the corresponding DTT activity. We also identified several PM constituents (WSOC, BrC, iron, and titanium) that were significantly correlated with AUC for summer samples. The strong correlation between organic species and ROS/RNS production highlights a need to understand the contribution of organic aerosols to PM-induced health effects. No significant correlations were observed for other ROS/RNS metrics or PM constituents, and no spatial trends were observed.For laboratory-generated aerosol, precursor identity influenced oxidative potentials significantly, with isoprene and naphthalene SOA having the lowest and highest DTT activities, respectively. Both precursor identity and formation condition significantly influenced inflammatory responses induced by SOA exposure, and several response patterns were identified for SOA precursors whose photooxidation products share similar carbon-chain length and functionalities. The presence of iron sulfate seed particles did not have an apparent effect on oxidative potentials; however, a higher level of ROS/RNS production was observed for all SOA formed in the presence of iron sulfate compared with ammonium sulfate. We also identified a significant positive correlation between ROS/RNS production and average carbon oxidation state, a bulk aerosol property. It may therefore be possible to roughly estimate ROS/RNS production using this property, which is readily obtainable. This correlation may have significant implications as aerosols have an atmospheric lifetime of a week, during which average carbon oxidation state increases because of atmospheric photochemical aging. Our results suggest that aerosols might become more toxic as they age in the atmosphere. Finally, in the context of ambient samples, laboratory-generated SOA induced comparable or higher levels of ROS/RNS. Oxidative potentials for all laboratory SOA systems, with the exception of naphthalene (which was higher), were all comparable with oxidative potentials observed in ambient samples.


Assuntos
Aerossóis/metabolismo , Aerossóis/farmacologia , Bioensaio , Estresse Oxidativo/efeitos dos fármacos , Material Particulado/metabolismo , Material Particulado/farmacologia , Humanos , Laboratórios , Material Particulado/análise
4.
J Environ Radioact ; 208-209: 106010, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31302578

RESUMO

Uranium mining activities expose uranium ore and mine tailings to the surface environment, where the release of radionuclides is facilitated by weathering at rates exceeding those typically found in nature. Therefore, close to former uranium mining sites, radionuclides and especially uranium concentrations in water may surpass local background levels. The methodology proposed herein, entails coupling, gamma-ray mapping, water sampling and chemical analyses including DGT (Diffusive Gradient in Thin Film) measurements, provides new insights into describing the environment of the La Commanderie site (France). Gamma-ray mapping allows identifying water seepage, output from a waste rock pile, as a potential pathway for radionuclides into the environment. Water seepage monitoring has shown: a low pH value (4.2), high sulfate content (179 mg.L-1) and high uranium concentrations of up to 436 µg.L-1. These recordings indicate that an acid mining drainage (AMD) process is occurring inside or under the oxidized parts of the waste rock pile. Monitoring data over three flow periods revealed the release of the highest uranium concentrations during a high-flow period downstream of the site, which is compliant with local regulations. The AMD process is also responsible for the release of significant amounts of Fe, Mn and As within the immediate environment in both dissolved and particulate forms. Changes in dissolved oxygen concentration and redox potential during low flow periods, modify the speciation of Fe (in AMD waters) which acts as a scavenger for other elements such as As, Mn and U. The use of DGT under environmental conditions, and specifically AMD waters, seems to be relevant in comparison to filtered spot water sampling strategies. Moreover, based on DGT measurements, the dissolved part of the released uranium is considered as labile with concentrations above the environmental standards for freshwater organisms.


Assuntos
Monitoramento de Radiação , Oligoelementos/análise , Poluentes Radioativos da Água/análise , França , Mineração , Urânio/análise
5.
Astron Astrophys ; 6042017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29093599

RESUMO

CONTEXT: Protoplanetary disks undergo substantial mass-loss by photoevaporation, a mechanism which is crucial to their dynamical evolution. However, the processes regulating the gas energetics have not been well constrained by observations so far. AIMS: We aim at studying the processes involved in disk photoevaporation when it is driven by far-UV photons (i.e. 6 < E < 13.6 eV). METHODS: We present a unique Herschel survey and new ALMA observations of four externally-illuminated photoevaporating disks (a.k.a. proplyds). For the analysis of these data, we developed a 1D model of the photodissociation region (PDR) of a proplyd, based on the Meudon PDR code and we computed the far infrared line emission. RESULTS: With this model, we successfully reproduce most of the observations and derive key physical parameters, i.e. densities at the disk surface of about 106 cm-3 and local gas temperatures of about 1000 K. Our modelling suggests that all studied disks are found in a transitional regime resulting from the interplay between several heating and cooling processes that we identify. These differ from those dominating in classical PDRs i.e. grain photo-electric effect and cooling by [OI] and [CII] FIR lines. This specific energetic regime is associated to an equilibrium dynamical point of the photoevaporation flow: the mass-loss rate is self-regulated to keep the envelope column density at a value that maintains the temperature at the disk surface around 1000 K. From the physical parameters derived from our best-fit models, we estimate mass-loss rates - of the order of 10-7 M⊙/yr - that are in agreement with earlier spectroscopic observation of ionised gas tracers. This holds only if we assume photoevaporation in the supercritical regime where the evaporation flow is launched from the disk surface at sound speed. CONCLUSIONS: We have identified the energetic regime regulating FUV-photoevaporation in proplyds. This regime could be implemented into models of the dynamical evolution of protoplanetary disks.

6.
Biomater Sci ; 3(6): 787-99, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26221839

RESUMO

Therapeutic proteins can face substantial challenges to their activity, requiring protein modification or use of a delivery vehicle. Nanoparticles can significantly enhance delivery of encapsulated cargo, but traditional small molecule carriers have some limitations in their use for protein delivery. Nanoparticles made from protein have been proposed as alternative carriers and have benefits specific to therapeutic protein delivery. This review describes protein nanoparticles made by self-assembly, including protein cages, protein polymers, and charged or amphipathic peptides, and by desolvation. It presents particle fabrication and delivery characterization for a variety of therapeutic and model proteins, as well as comparison of the features of different protein nanoparticles.


Assuntos
Portadores de Fármacos/química , Nanopartículas/administração & dosagem , Nanopartículas/química , Peptídeos/administração & dosagem , Proteínas/química , Sistemas de Liberação de Medicamentos , Humanos , Peptídeos/química
7.
J Psychiatr Ment Health Nurs ; 21(8): 679-86, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23992114

RESUMO

The aim of this study was to elucidate the experience of participation in four sessions of cognitive behavioural group therapy for psychological distress for female university students' (n = 19), aged 22-45 years. Data were gathered with semi-structured interviews during March and April 2008 and analysed according to thematic content analysis. The results identified four themes: 'Gaining knowledge and understanding', 'Becoming more balanced and positive in thinking', 'Feeling more self-confident and in control' and 'Opportunities for practice and in-depth reflections'. Future recommendations include an increase in sessions from four to five, with one booster session to follow-up on newly acquired skills.


Assuntos
Terapia Cognitivo-Comportamental/métodos , Psicoterapia de Grupo/métodos , Estresse Psicológico/psicologia , Estresse Psicológico/terapia , Estudantes/psicologia , Adulto , Feminino , Humanos , Universidades , Adulto Jovem
8.
Dalton Trans ; 41(28): 8615-23, 2012 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-22678751

RESUMO

The in vivo(212)Pb/(212)Bi generator is promising for application in targeted alpha therapy (TAT) of cancer. One main limitation of its therapeutic application is due to potential release of (212)Bi from the radioconjugate upon radioactive decay of the mother nuclide (212)Pb, potentially leading to irradiation of healthy tissue. The objective of the present work is to assess whether the chelate CHX-A''-DTPA (N-(2-aminoethyl)-trans-1,2-diaminocyclohexane-N,N',N''-pentaacetic acid) bound to a biological carrier molecule may be able to re-complex released (212)Bi under in vivo conditions to limit its translocation from the target site. CHX-A''-DTPA was bound to bovine gamma globulin (BGG) to mimic a model conjugate and the stability of the Bi-CHX-A''-DTPA-BGG conjugate was studied in blood serum by ultrafiltration. TRLFS experiments using Cm(III) as a fluorescent probe demonstrated that linking CHX-A''-DTPA to BGG does not affect the coordination properties of the ligand. Furthermore, comparable stability constants were observed between Bi(III) and free CHX-A''-DTPA, BGG-bound CHX-A''-DTPA and DTPA. The complexation constants determined between Bi(III) and the chelate molecules are sufficiently high to allow ultra trace amounts of the ligand to efficiently compete with serum transferrin controlling Bi(III) speciation in blood plasma conditions. Nevertheless, CHX-A''-DTPA is not able to complex Bi(III) generated in blood serum because of the strong competition between Bi(III) and Fe(II) for the ligand. In other words, CHX-A''-DTPA is not "selective" enough to limit Bi(iii) release in the body when applying the (212)Pb/(212)Bi in vivo generator.


Assuntos
Bismuto/sangue , Quelantes/metabolismo , Isotiocianatos/sangue , Ácido Pentético/análogos & derivados , Ácido Pentético/sangue , Animais , Bovinos , Ácido Edético/sangue , Humanos , Técnicas In Vitro , gama-Globulinas/metabolismo
9.
Obes Surg ; 22(6): 956-66, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22438220

RESUMO

The prevalence of obesity continues to escalate in the USA; however, there is no consensus regarding the optimal therapy for obesity. For the vast majority of severely obese patients, conventional medical therapies (i.e., diet, exercise, behavioral counseling) often fail over the long term. Existing pharmacotherapy adjunctive to behavioral therapy has limited effectiveness and an imperfect safety record. In contrast, bariatric surgery has a high degree of weight loss efficacy, yet only a small fraction of the qualifying obese population undergoes these procedures because of the associated perioperative risks and potential late complications. In addition, the role of bariatric surgery is unclear in certain patient populations, such as patients with lower body mass index (BMI, 30-35 kg/m(2)), the high-risk super-super obese patients (BMI > 60), the morbidly obese adolescent, and obese patients requiring weight reduction in preparation for other procedures, such as orthopedic, transplant, or vascular surgeries. In these circumstances, there is a need for an effective but less invasive treatment to bridge the gap between medical and surgical therapy. This review examines current treatment outcomes, identifies prominent areas of unmet clinical needs, and provides an overview of two minimally invasive "temporary procedures for weight loss" that may eventually address some of the unmet needs in obesity management.


Assuntos
Terapia Comportamental/métodos , Derivação Gástrica/métodos , Avaliação das Necessidades , Obesidade Mórbida/reabilitação , Fármacos Antiobesidade/uso terapêutico , Depressores do Apetite/uso terapêutico , Terapia Comportamental/tendências , Índice de Massa Corporal , Exercício Físico , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Masculino , Obesidade Mórbida/tratamento farmacológico , Obesidade Mórbida/cirurgia , Estados Unidos/epidemiologia
10.
Anal Chim Acta ; 721: 182-8, 2012 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-22405318

RESUMO

Astatine is a rare radioelement belonging to the halogen group. Considering the trace amounts of astatine produced in cyclotrons, its chemistry cannot be evaluated by spectroscopic tools. Analytical tools, provided that they are coupled with a radioactive detection system, may be an alternative way to study its chemistry. In this research work, high performance anion exchange chromatography (HPAEC) coupled to a gamma detector (γ) was used to evaluate astatine species under reducing conditions. Also, to strengthen the reliability of the experiments, a quantitative analysis using a reactive transport model has been done. The results confirm the existence of one species bearing one negative charge in the pH range 2-7.5. With respect to the other halogens, its behavior indicates the existence of negative ion, astatide At(-). The methodology was successfully applied to the speciation of the astatine in human serum. Under fixed experimental conditions (pH 7.4-7.5 and redox potential of 250 mV) astatine exists mainly as astatide At(-) and does not interact with the major serum components. Also, the method might be useful for the in vitro stability assessment of (211)At-labeled molecules potentially applicable in nuclear medicine.


Assuntos
Astato/sangue , Cromatografia por Troca Iônica , Raios gama , Ânions/química , Cromatografia Líquida de Alta Pressão , Humanos , Concentração de Íons de Hidrogênio , Oxirredução , Radiometria
11.
Int Nurs Rev ; 58(1): 61-7, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21281295

RESUMO

BACKGROUND: Evidence suggests that multiple influences on sexual behaviour of adolescents exist, ranging from relationships with significant others including sexual or physical abuse and childhood molestation to substances used prior to sex and environmental circumstances such as sex work. PURPOSE: This study aims to describe associations between childhood molestation and sexual risk behaviour. METHOD: African American and Mexican American adolescent women aged 14-18 years (n=562) with sexually transmitted infection (STI) or abuse histories and enrolled in a randomized controlled trial of behavioural interventions were interviewed via self-report concerning sexual risk behaviour, abuse and childhood molestation at study entry. RESULTS: Sexual (59%), physical (77%) and psychological (82%) abuse and childhood molestation (25%) were self-reported without differences by ethnicity. Adolescents reporting childhood molestation experienced more forms of sexual, physical and psychological abuse than others and higher incidences of STI. Fewer attended school; however, more had arrests, convictions, incarcerations and probations. Stressors including depression, running away, thoughts of death and suicide were highest for those reporting childhood molestation. Those reporting childhood molestation engaged in higher sexual risk behaviours than adolescents experiencing other forms of sexual or physical abuse (lifetime partners, bisexual relationships, anal and group sex, sex with friends with benefits, sex for money, concurrent partners, drug use including multiple substances, alcohol use and alcohol problems). These adolescents reported 'getting high' and having sex when out of control as reasons for sex with multiple partners. CONCLUSION: Interventions for abused adolescent women necessitate a focus on associations between childhood molestation and a multiplicity of sexual risk behaviours for prevention of abuse, substance use and sex work, STI/human immunodeficiency virus (HIV) and sequelae.


Assuntos
Comportamento do Adolescente/psicologia , Negro ou Afro-Americano/psicologia , Americanos Mexicanos/psicologia , Assunção de Riscos , Delitos Sexuais/psicologia , Comportamento Sexual/psicologia , Adolescente , Comportamento do Adolescente/etnologia , Distribuição de Qui-Quadrado , Feminino , Humanos , Entrevistas como Assunto , Fatores de Risco , Delitos Sexuais/etnologia , Comportamento Sexual/etnologia
12.
J Phys Chem A ; 114(1): 576-82, 2010 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-20014840

RESUMO

A combined experimental and theoretical approach is used to define astatine (At) speciation in acidic aqueous solution and to answer the two main questions raised from literature data: does At(0) exist in aqueous solution and what is the chemical form of At(+III), if it exists. The experimental approach considers that a given species is characterized by its distribution coefficient (D) experimentally determined in a biphasic system. The change in speciation arising from a change in experimental conditions is observed by a change in D value. The theoretical approach involves quasi-relativistic quantum chemistry calculations. The results show that At at the oxidation state 0 cannot exist in aqueous solution. The three oxidation states present in the range of water stability are At(-I), At(+I), and At(+III) and exist as At(-), At(+), and AtO(+), respectively, in the 1-2 pH range. The standard redox potentials of the At(+)/At(-) and AtO(+)/At(+) couples have been determined, the respective values being 0.36 +/- 0.01 and 0.74 +/- 0.01 V vs NHE.


Assuntos
Astato/química , Ácido Nítrico/química , Oxirredução , Teoria Quântica , Soluções
14.
Sex Transm Infect ; 85(4): 283-9, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19174424

RESUMO

OBJECTIVES: Young black women are disproportionately affected by sexually transmitted infections (STI) in the UK, but effective interventions to address this are lacking. The Young Brent Project explored the nature and context of sexual risk-taking in young people to inform the translation of an effective clinic-based STI reduction intervention (Project SAFE) from the USA to the UK. METHODS: One-to-one in-depth interviews (n = 37) and group discussions (n = 10) were conducted among men and women aged 15-27 years from different ethnic backgrounds recruited from youth and genitourinary medicine clinic settings in Brent, London. The interviews explored the context within which STI-related risks were assessed, experienced and avoided, the skills needed to recognise risk and the barriers to behaviour change. RESULTS: Concurrent sexual partnerships, mismatched perceptions and expectations, and barriers to condom use contributed to STI risk exposure and difficulties in implementing risk-reduction strategies. Women attempted to achieve monogamy, but experienced complex and fluid sexual relationships. Low risk awareness, flawed partner risk assessments, negative perceptions of condoms and lack of control hindered condom use. Whereas men made conscious decisions, women experienced persuasion, deceit and difficulty in requesting condom use, particularly with older partners. CONCLUSIONS: Knowledge of STI and condom use skills is not enough to equip young people with the means to reduce STI risk. Interventions with young women need to place greater emphasis on: entering and maintaining healthy relationships; awareness of risks attached to different forms of concurrency and how concurrency arises; skills to redress power imbalances and building self-esteem.


Assuntos
Preservativos/estatística & dados numéricos , Conhecimentos, Atitudes e Prática em Saúde , Grupos Minoritários , Comportamento Sexual/etnologia , Infecções Sexualmente Transmissíveis/etnologia , Adolescente , Adulto , Fatores Etários , População Negra/etnologia , Região do Caribe/etnologia , Estudos de Viabilidade , Feminino , Humanos , Relações Interpessoais , Entrevistas como Assunto , Londres/epidemiologia , Masculino , Ensaios Clínicos Controlados Aleatórios como Assunto , Comportamento Sexual/psicologia , Infecções Sexualmente Transmissíveis/prevenção & controle , Estados Unidos , Saúde da Mulher/etnologia , Adulto Jovem , Iugoslávia/etnologia
15.
Phys Rev Lett ; 101(23): 237201, 2008 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-19113586

RESUMO

Tb2Sn2O7 has been proposed as an ordered spin ice, but the precise nature of the low temperature magnetic state remains uncertain. Recent independent muon spin relaxation (microSR) investigations suggest the possibility of exotic ground states with static order precluded on time scales longer than 10(-6) s. Here the more conventional hypothesis of canted ferromagnetism is tested by means of microSR with the muons stopped outside the sample, as well as ultralow field bulk magnetization measurements. The field cooled state shows conventional static order, while the zero field cooled state may be interpreted in terms of conventional closed domains. These results rule out purely dynamical ground states and illustrate the value of exterior muon implantation as a complement to the conventional technique.

16.
Cancer ; 112(11): 2500-8, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18386829

RESUMO

BACKGROUND: Sunitinib malate is a novel multitargeted receptor tyrosine kinase inhibitor with established efficacy in the treatment of metastatic renal cell carcinoma and imatinib-resistant gastrointestinal stromal tumor. This report describes the development of heart failure in cancer patients who received this novel agent. METHODS: A retrospective study was conducted at M. D. Anderson Cancer Center during a 1-year period on patients who received sunitinib and developed heart failure. RESULTS: During 2006, 6 of 224 (2.7%) patients who received sunitinib developed heart failure (HF) that resulted in substantial morbidity and, in some cases, mortality. Symptomatic heart failure occurred soon after initiation of sunitinib (mean onset 22 days after initiation), was associated with decline in cardiac function and elevations in blood pressure, and was not completely reversible in most patients, even after termination of sunitinib therapy. CONCLUSIONS: These observations suggested that sunitinib-associated heart failure may represent a potentially serious toxicity and underscore the need for careful monitoring of cardiac function and aggressive control of hypertension in these patients. Studies to elucidate potential mechanisms of heart failure and left ventricular dysfunction resulting from treatment with sunitinib are necessary to develop strategies for prevention and treatment of this complication.


Assuntos
Antineoplásicos/efeitos adversos , Insuficiência Cardíaca/induzido quimicamente , Indóis/efeitos adversos , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/efeitos adversos , Pirróis/efeitos adversos , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Tirosina Quinases/antagonistas & inibidores , Estudos Retrospectivos , Sunitinibe
19.
Cancer ; 109(3): 621-7, 2007 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-17167763

RESUMO

BACKGROUND: Patients with cancer who have thrombocytopenia may experience acute coronary syndromes (ACS), and the use of aspirin (ASA) poses an increased risk of bleeding. The purpose of this study was to test the hypothesis that the benefit of ASA therapy in the treatment of ACS would extend to cancer patients with thrombocytopenia and outweigh the risks of severe bleeding. METHODS: The records of all cancer patients diagnosed with an ACS in 2001 and referred for cardiology consultation were reviewed. Patients were divided into 2 groups on the basis of platelet count, >100 cells k/microL and < or = 100 cells k/microL. Data were collected on the use of ASA therapy, bleeding complications, and survival rates. The authors assessed group differences by using the Wilcoxon rank sum test or 2-tailed Fisher exact test, as appropriate. Univariate and multivariate logistic regression models were used to assess factors potentially associated with 7-day survival. RESULTS: In cancer patients with ACS and thrombocytopenia, those who did not receive ASA had a 7-day survival rate of 6% compared with 90% in those who did receive ASA (P < .0001). There were no severe bleeding complications. Patients with a platelet count (>100 cells k/microL) who received ASA had a 7-day survival rate of 88% compared with 45% in those who did not receive ASA (P = .0096). CONCLUSIONS: Therapy with ASA was associated with a significantly improved 7-day survival after ACS in cancer patients, with or without thrombocytopenia, and not associated with more severe bleeding.


Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Aspirina/uso terapêutico , Doença das Coronárias/prevenção & controle , Infarto do Miocárdio/prevenção & controle , Neoplasias/complicações , Trombocitopenia/prevenção & controle , Doença Aguda , Idoso , Doença das Coronárias/tratamento farmacológico , Doença das Coronárias/etiologia , Feminino , Hemorragia/complicações , Humanos , Masculino , Prontuários Médicos , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/etiologia , Avaliação de Resultados em Cuidados de Saúde , Contagem de Plaquetas , Estudos Retrospectivos , Taxa de Sobrevida , Trombocitopenia/tratamento farmacológico , Trombocitopenia/etiologia
20.
Res Vet Sci ; 83(1): 47-52, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17187835

RESUMO

Q fever is a zoonosis caused by the obligate intracellular bacterium, Coxiella burnetii. Aborting domestic ruminants are the main source of human infection. In January 2003, an abortion episode occurred in a dairy caprine herd where 18/60 (30%) goats experienced reproductive problems: 4/60 (7%) aborted and 14/60 (23%) had stillbirths. Serological screening for abortion-related infectious diseases suggested Q fever. The diagnosis of C. burnetii infection was confirmed with PCR based on the occurrence of C. burnetii shedding into vaginal mucus, faeces and colostrums taken after kidding from the affected animals. The pregnancy following this episode resulted in one abortion and four stillbirths; three of those goats had already experienced reproductive failure during the previous kidding season. The seroprevalence of C. burnetii infection and the bacteria shedding were investigated using both ELISA and PCR assays, respectively, during the course of the initial and subsequent kidding seasons. Serological testing, performed on the whole herd 6 weeks after the abortion episode, showed 48/60 (80%) of ELISA positive goats. PCR assay performed on both vaginal swab and milk samples showed that the bacterium was shed for almost four months after the outbreak. C. burnetii DNA was also amplified from vaginal swab and milk samples taken from goats after the second kidding season. Furthermore, the bacteria were found into 14 vaginal swabs and 12 milk samples taken from infected females at both kidding seasons.


Assuntos
Coxiella burnetii/isolamento & purificação , Doenças das Cabras/microbiologia , Febre Q/veterinária , Aborto Animal/microbiologia , Animais , Feminino , Cabras , Leite/microbiologia , Parto , Reação em Cadeia da Polimerase/veterinária , Gravidez , Complicações Infecciosas na Gravidez/microbiologia , Complicações Infecciosas na Gravidez/veterinária , Febre Q/complicações , Natimorto/veterinária , Fatores de Tempo , Vagina/microbiologia
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