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1.
Eur Arch Psychiatry Clin Neurosci ; 272(4): 679-692, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34622343

RESUMO

Substantial evidence shows that physical activity and fitness play a protective role in the development of stress related disorders. However, the beneficial effects of fitness for resilience to modern life stress are not fully understood. Potentially protective effects may be attributed to enhanced resilience via underlying psychosocial mechanisms such as self-efficacy expectations. This study investigated whether physical activity and fitness contribute to prospectively measured resilience and examined the mediating effect of general self-efficacy. 431 initially healthy adults participated in fitness assessments as part of a longitudinal-prospective study, designed to identify mechanisms of resilience. Self-efficacy and habitual activity were assessed in parallel to cardiorespiratory and muscular fitness, which were determined by a submaximal step-test, hand strength and standing long jump test. Resilience was indexed by stressor reactivity: mental health problems in relation to reported life events and daily hassles, monitored quarterly for nine months. Hierarchical linear regression models and bootstrapped mediation analyses were applied. We could show that muscular and self-perceived fitness were positively associated with stress resilience. Extending this finding, the muscular fitness-resilience relationship was partly mediated by self-efficacy expectations. In this context, self-efficacy expectations may act as one underlying psychological mechanism, with complementary benefits for the promotion of mental health. While physical activity and cardiorespiratory fitness did not predict resilience prospectively, we found muscular and self-perceived fitness to be significant prognostic parameters for stress resilience. Although there is still more need to identify specific fitness parameters in light of stress resilience, our study underscores the general relevance of fitness for stress-related disorders prevention.


Assuntos
Aptidão Física , Autoeficácia , Adulto , Estudos Transversais , Humanos , Estudos Prospectivos , Estresse Psicológico
2.
Ecotoxicol Environ Saf ; 230: 113143, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34998262

RESUMO

Neurotoxic methylmercury (MeHg) accumulates in rice grain from paddy soil, where its concentration is controlled by microbial mercury methylation and demethylation. Both up- and down-regulation of methylation is known to occur in the presence of rice plants in comparison to non-vegetated paddy soils; the influence of rice plant presence/absence on demethylation is unknown. To assess the concurrent influence of rice plant presence/absence on methylation and demethylation, and to determine which process was more dominant in controlling soil MeHg concentrations, we maintained six rhizoboxes of paddy soil with and without rice plants. At the peak of plant growth, we simultaneously measured ambient MeHg, ambient inorganic mercury (IHg), and potential rate constants of methylation and demethylation (Kmeth and Kdemeth) in soil using stable isotope tracers and ID-GC-ICPMS. We also measured organic matter content, elemental S, and water-extractable sulfate. We found MeHg concentrations were differentially controlled by MeHg production and degradation processes, depending on whether plants were present. In non-vegetated boxes, MeHg concentration was controlled by Kmeth, as evidenced by a strong and positive correlation, while Kdemeth had no relation to MeHg concentration. These results indicate methylation was the dominant driver of MeHg concentration in non-vegetated soil. In vegetated boxes, Kdemeth strongly and negatively predicted MeHg concentration, indicating that demethylation was the dominant control in soil with plants. MeHg concentration, Kmeth, and % MeHg all had significantly less variance in vegetated than in non-vegetated soils due to a consistent elimination of greater values. This pattern suggests that reduced MeHg production capacity was a secondary control on MeHg concentrations in vegetated soils. We observed no difference in the magnitude or variance of Kdemeth between treatments, suggesting that demethylation was robust to soil chemical conditions influenced by the plant, perhaps because of a wider taxonomic diversity of demethylators. Our results suggest that methylation and demethylation processes could both be leveraged to alter MeHg concentrations in rice paddy soil.

3.
Eur Arch Psychiatry Clin Neurosci ; 271(6): 1035-1051, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32683526

RESUMO

Resilience is the maintenance and/or quick recovery of mental health during and after periods of adversity. It is conceptualized to result from a dynamic process of successful adaptation to stressors. Up to now, a large number of resilience factors have been proposed, but the mechanisms underlying resilience are not yet understood. To shed light on the complex and time-varying processes of resilience that lead to a positive long-term outcome in the face of adversity, the Longitudinal Resilience Assessment (LORA) study has been established. In this study, 1191 healthy participants are followed up at 3- and 18-month intervals over a course of 4.5 years at two study centers in Germany. Baseline and 18-month visits entail multimodal phenotyping, including the assessment of mental health status, sociodemographic and lifestyle variables, resilience factors, life history, neuropsychological assessments (of proposed resilience mechanisms), and biomaterials (blood for genetic and epigenetic, stool for microbiome, and hair for cortisol analysis). At 3-monthly online assessments, subjects are monitored for subsequent exposure to stressors as well as mental health measures, which allows for a quantitative assessment of stressor-dependent changes in mental health as the main outcome. Descriptive analyses of mental health, number of stressors including major life events, daily hassles, perceived stress, and the ability to recover from stress are here presented for the baseline sample. The LORA study is unique in its design and will pave the way for a better understanding of resilience mechanisms in humans and for further development of interventions to successfully prevent stress-related disorder.


Assuntos
Resiliência Psicológica , Estresse Psicológico , Alemanha , Humanos , Estudos Longitudinais , Estresse Psicológico/psicologia
4.
Limnol Oceanogr ; 64(3): 1333-1346, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31741542

RESUMO

Arsenic contamination of lakebed sediments is widespread due to a range of human activities, including herbicide application, waste disposal, mining, and smelter operations. The threat to aquatic ecosystems and human health is dependent on the degree of mobilization from sediments into overlying water columns and exposure of aquatic organisms. We undertook a mechanistic investigation of arsenic cycling in two impacted lakes within the Puget Sound region, a shallow weakly-stratified lake and a deep seasonally-stratified lake, with similar levels of lakebed arsenic contamination. We found that the processes that cycle arsenic between sediments and the water column differed greatly in shallow and deep lakes. In the shallow lake, seasonal temperature increases at the lakebed surface resulted in high porewater arsenic concentrations that drove larger diffusive fluxes of arsenic across the sediment-water interface compared to the deep, stratified lake where the lakebed remained ~10#x00B0;C cooler. Plankton in the shallow lake accumulated up to an order of magnitude more arsenic than plankton in the deep lake due to elevated aqueous arsenic concentrations in oxygenated waters and low phosphate: arsenate ratios in the shallow lake. As a result, strong arsenic mobilization from sediments in the shallow lake was countered by large arsenic sedimentation rates out of the water column driven by plankton settling.

5.
Nanotechnology ; 26(21): 215701, 2015 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-25930680

RESUMO

The magnetization reversal of three-segment cylindrical nanoelements comprising alternating nanowire and nanotube sections is investigated by means of Monte Carlo simulations. Such nanoelements may feature a three-state behaviour with an intermediate plateau in the hysteresis curve due to a metastable pinning of the domain walls (DWs) at the wire-tube interfaces. It turns out that vortex as well as transverse DWs contribute to the magnetization reversal. By varying the geometric parameters, the sequence, or the material of the elements the nucleation location of DWs, as well as their nucleation field, can be tailored. Especially interesting is the novel possibility to drive DWs coherently in the same or in opposite directions by changing the geometry of the hybrid nanoelement. This important feature provides additional flexibility to the construction of logical devices based on DW movement. Another prominent outcome is that DWs can be nucleated near the centre of the element and then traverse to the outer tips of the cylindrical structure when the applied field is increased, which also opens the possibility to use these three-segment nanoelements for the field-induced delivery of DWs as substitutes for large nucleation pads.

6.
Clin Radiol ; 69(7): 687-94, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24625692

RESUMO

AIM: To evaluate the role of diffusion-weighted magnetic resonance imaging (DW-MRI) in the differentiation of hepatic abscesses from non-infected fluid collections. MATERIALS AND METHODS: In this retrospective study, 22 hepatic abscesses and 27 non-infected hepatic fluid collections were examined in 27 patients who underwent abdominal MRI including DW-MRI. Two independent observers reviewed T2-weighted + DW-MRI and T2-weighted + contrast-enhanced T1-weighted (CET1W) images in two sessions. Detection rates and confidence levels were calculated and compared using McNemar's and Wilcoxon's signed rank tests, respectively. Apparent diffusion coefficient (ADC) values of abscesses and non-infected fluid collections were compared using the t-test. Receiver operating characteristic (ROC) curves were constructed. RESULTS: There was no statistically significant difference in the accuracy of detecting abscesses using T2-weighted + DW-MRI (both observers: 21/22, 95.5%) versus T2-weighted + CET1W images (observer 1: 21/22, 95.5%; observer 2: 22/22, 100%; p < 0.01). Mean ADC values were significantly lower with abscesses versus non-infected fluid collections (0.83 ± 0.24 versus 2.25 ± 0.61 × 10(-3) mm(2)/s; p < 0.001). With ROC analysis there was good discrimination of abscess from non-infected fluid collections at a threshold ADC value of 1.36 × 10(-3) mm(2)/s. CONCLUSION: DW-MRI allows qualitative and quantitative differentiation of abscesses from non-infected fluid collections in the liver.


Assuntos
Abscesso Hepático/diagnóstico , Meios de Contraste , Diagnóstico Diferencial , Imagem de Difusão por Ressonância Magnética/métodos , Exsudatos e Transudatos , Feminino , Gadolínio DTPA , Humanos , Masculino , Pessoa de Meia-Idade , Padrões de Referência , Estudos Retrospectivos , Fatores de Tempo
7.
Nat Genet ; 29(2): 217-22, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11586303

RESUMO

There is considerable interest in understanding patterns of linkage disequilibrium (LD) in the human genome, to aid investigations of human evolution and facilitate association studies in complex disease. The relative influences of meiotic crossover distribution and population history on LD remain unclear, however. In particular, it is uncertain to what extent crossovers are clustered into 'hot spots, that might influence LD patterns. As a first step to investigating the relationship between LD and recombination, we have analyzed a 216-kb segment of the class II region of the major histocompatibility complex (MHC) already characterized for familial crossovers. High-resolution LD analysis shows the existence of extended domains of strong association interrupted by patchwork areas of LD breakdown. Sperm typing shows that these areas correspond precisely to meiotic crossover hot spots. All six hot spots defined share a remarkably similar symmetrical morphology but vary considerably in intensity, and are not obviously associated with any primary DNA sequence determinants of hot-spot activity. These hot spots occur in clusters and together account for almost all crossovers in this region of the MHC. These data show that, within the MHC at least, crossovers are far from randomly distributed at the molecular level and that recombination hot spots can profoundly affect LD patterns.


Assuntos
Genes MHC da Classe II , Meiose/genética , Recombinação Genética , Troca Genética , DNA/genética , Humanos , Desequilíbrio de Ligação , Masculino , Polimorfismo Genético , Espermatozoides/metabolismo
8.
Nat Genet ; 8(2): 162-70, 1994 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7842015

RESUMO

Human minisatellite mutation in the male germline frequently involves complex interallelic gene conversion events restricted to one end of the tandem repeat array. Some alleles at minisatellite MS32 show reduced variability in human populations and are associated with a G to C transversion upstream of the array. Analysis of single sperm demonstrated a frequently profound reduction in mutation rate at alleles carrying the C variant. This mutation suppression acts in cis, but does not affect the ability of an allele to act as sequence donor during gene conversion. This mutation rate polymorphism provides strong evidence for elements near the minisatellite that regulate tandem repeat instability.


Assuntos
DNA Satélite/genética , Mutação , Polimorfismo Genético , África , Alelos , Povo Asiático/genética , Sequência de Bases , População Negra/genética , Conversão Gênica , Haplótipos , Humanos , Japão , Masculino , Dados de Sequência Molecular , Sequências Repetitivas de Ácido Nucleico , Espermatozoides , População Branca/genética
9.
World J Biol Psychiatry ; 24(9): 838-848, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37334645

RESUMO

OBJECTIVES: The outbreak of Covid-19 negatively affected mental health and increased loneliness. The subjective feeling of loneliness is influenced by genetic and social factors and has a negative impact on mental health. METHODS: From March 2020 to June 2021 loneliness was investigated in N = 517 individuals using monthly acquired questionnaire data and Latent Growth Curve Analysis. Associations of social factors and polygenic risk scores (PRSs, n = 361) with class membership were investigated. RESULTS: Three classes ("average", 40%; "not lonely", 38%; "elevated loneliness", 22%) were identified, that differ significantly regarding loneliness, mental dysfunction, and response to the lockdown phases. Individuals with a high PRS for neuroticism are more likely to belong to the "elevated loneliness" class, living with another person is a protective factor. CONCLUSION: As the "elevated loneliness" class was at the highest risk of mental dysfunction, our findings underscore the importance of identifying those individuals to implement counteractive measures.


Assuntos
COVID-19 , Saúde Mental , Humanos , Solidão , Fatores Sociais , Pandemias , Controle de Doenças Transmissíveis , Alemanha/epidemiologia , Fatores de Risco
10.
J Nanosci Nanotechnol ; 11(5): 3943-8, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21780390

RESUMO

Luminescent nanorods of potassium acid phthalate (KAP) doped with rhodamine 6G (Rh 6G) dye molecules were grown by template assisted crystallization. Pores with diameters ranging from tens of nanometers to few micrometers were obtained in polycarbonate foils after heavy-ion irradiation and subsequent chemical etching of the damage trails along the ion trajectories. Crystallization from solution was employed for filling of the pores with the dye-doped KAP rods. These nanostructures were characterized using scanning electron microscopy, optical absorption spectroscopy and photoluminescence detection. X-ray diffraction was used for structural analysis. The luminescence of the dye-doped rods undergoes a redshift when the diameter of the structures decreases. This shift is probably caused by increasing dye concentration in the rods with decreasing pore diameter. The luminescence originating from the Rh 6G presence is up-converted due to the second-harmonic generation in KAP.

11.
Vasa ; 40(4): 308-14, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21780055

RESUMO

BACKGROUND: Transarterial catheter embolization of the kidneys (TAE) is a minimally invasive, image-guided procedure. In this study outcome and TAE-related complications of the patients who underwent TAE of the kidneys were evaluated retrospectively. PATIENTS AND METHODS: Between August 2003 and August 2009, 11 patients underwent selective percutaneous transarterial renal embolization for end stage renal disease associated with uncontrolled hypertension, nephrotic syndrome, bleeding or malignancy. TAE of renal arteries was performed using different embolization agents. RESULTS: Successful renal embolization was possible in all 21 kidneys. All patients became anuric. Non-target embolization was not detectable. Nevertheless, all patients developed some degree of postembolization symptoms including nausea, vomiting, fever or pain. A typical finding after embolization was an increase in the C-reactive protein. CONCLUSIONS: Renal embolization is rarely done but should be considered as an alternative to surgical nephrectomy in patients with end stage renal disease due to the lesser invasiveness. Our study confirms the safety and effectivity of percutaneous renal embolization in patients with ESRD. We were able to control the hypertension, nephrotic syndrome, and bleeding caused by ESRD.


Assuntos
Embolização Terapêutica , Falência Renal Crônica/terapia , Rim/irrigação sanguínea , Artéria Renal , Adulto , Idoso , Embolização Terapêutica/efeitos adversos , Feminino , Alemanha , Taxa de Filtração Glomerular , Hemorragia/etiologia , Hemorragia/terapia , Humanos , Hipertensão/etiologia , Hipertensão/terapia , Rim/fisiopatologia , Falência Renal Crônica/complicações , Falência Renal Crônica/diagnóstico por imagem , Falência Renal Crônica/fisiopatologia , Masculino , Pessoa de Meia-Idade , Síndrome Nefrótica/etiologia , Síndrome Nefrótica/terapia , Radiografia Intervencionista , Artéria Renal/diagnóstico por imagem , Estudos Retrospectivos , Resultado do Tratamento
12.
Transl Psychiatry ; 11(1): 392, 2021 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-34282129

RESUMO

The COVID-19 pandemic and resulting measures can be regarded as a global stressor. Cross-sectional studies showed rather negative impacts on people's mental health, while longitudinal studies considering pre-lockdown data are still scarce. The present study investigated the impact of COVID-19 related lockdown measures in a longitudinal German sample, assessed since 2017. During lockdown, 523 participants completed additional weekly online questionnaires on e.g., mental health, COVID-19-related and general stressor exposure. Predictors for and distinct trajectories of mental health outcomes were determined, using multilevel models and latent growth mixture models, respectively. Positive pandemic appraisal, social support, and adaptive cognitive emotion regulation were positively, whereas perceived stress, daily hassles, and feeling lonely negatively related to mental health outcomes in the entire sample. Three subgroups ("recovered," 9.0%; "resilient," 82.6%; "delayed dysfunction," 8.4%) with different mental health responses to initial lockdown measures were identified. Subgroups differed in perceived stress and COVID-19-specific positive appraisal. Although most participants remained mentally healthy, as observed in the resilient group, we also observed inter-individual differences. Participants' psychological state deteriorated over time in the delayed dysfunction group, putting them at risk for mental disorder development. Consequently, health services should especially identify and allocate resources to vulnerable individuals.


Assuntos
COVID-19 , Saúde Mental , Controle de Doenças Transmissíveis , Estudos Transversais , Alemanha/epidemiologia , Humanos , Pandemias , Fatores de Proteção , SARS-CoV-2
13.
Eur J Cancer Care (Engl) ; 19(6): 809-15, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20105224

RESUMO

The serodiagnostics of extracellular domain (ECD) HER-2/neu has turned into an evidenced-based tumour marker for HER-2/neu-positive breast cancer patients. This study investigated the clinical relevance of immunohistochemical and serum HER-2/neu in 44 patients with advanced ovarian cancer. The Hercept-Test® from DAKO Diagnostics was used to analyse immunohistochemical HER-2/neu expression. The HER-2/neu ECD in serum was determined quantitatively by Bayer Immuno 1™ Immunoanalyser. The HER-2/neu serum values were correlated to the clinical course of disease and to established prognostic factors, i.e. progression-free and overall survival. Some 23% of patients (n = 11) expressed HER-2/neu serum levels higher than 15 ng/mL, whereas only 7.7% (n = 2) of the patients examined by immunohistochemistry showed a HER-2/neu overexpression of the tissue. None of them revealed an overexpression of HER-2/neu ECD by serodiagnostics. HER-2/neu overexpression did not correlate significantly to any of the analysed prognostic factors. According to progression-free and overall survival, there was no significant difference between serologically HER-2/neu-positive or negative patients. For ovarian cancer patients, neither high HER-2/neu serum levels, nor immunohistochemically determined HER-2/neu positivity, appear to predict the course of disease. This study shows a lack of association between the immunohistochemical HER-2/neu status and the serum level of solute extracelluar HER-2/neu domain.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias Ovarianas/metabolismo , Receptor ErbB-2/metabolismo , Adulto , Idoso , Biomarcadores Tumorais/sangue , Progressão da Doença , Feminino , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/patologia , Prognóstico , Receptor ErbB-2/sangue , Análise de Sobrevida
14.
J Eur Acad Dermatol Venereol ; 24(5): 518-23, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-19807827

RESUMO

BACKGROUND: Variable Pulsed Light (VPL) is a new intensity pulse light (IPL) system. We evaluated VPL for safety and long-term efficacy in non-facial hair removal. STUDY DESIGN/MATERIAL AND METHODS: The Variable Pulsed Light [VPL System (Energist Limited, UK), 610-950 nm] system was used for the removal of unwanted non-facial dark pigmented body hair in 42 volunteers (40 females, two males, age: 18-43 years, mean: 30.4 +/- 7.4 years) with Fitzpatrick skin phototype (SPT) II (33.3%), III (38.1%) and IV (28.6%), and brown (43.8%) or black (56.2%) fine (19.0%), medium (47.6%) or coarse (9.4%) body hair. Minimum follow-up period was 12 months (mean: 13.14 +/- 2.38). Treatment parameters were as follows: number x duration of micropulses: 15 x 5-15 x 7 ms, pulse delay: 1-8 ms, fluence: 30-45 J/cm(2). RESULTS: Very good (> or =76% hair reduction) and good treatment efficacies (hair reduction: 51-75%) were observed in the majority of treated patients (n = 18; 42.9%; n = 14; 33.3% respectively), four patients (9.5%) had only moderate (hair reduction: 26-50%) and six (14.3%) patients had no (hair reduction < or =25%) treatment response. Side-effects (reversible erythema, leukotrichia) were sparse. More favourable long-term therapy outcomes were observed for higher SPT (III and IV), medium or coarse black hair and younger patients. CONCLUSION: The VPL System is a relatively efficient and safe treatment for long-term hair removal. Higher SPT (III and IV) with black and medium to coarse hair, and younger age of the patients appear to be factors of significant importance predicting long-term efficacy.


Assuntos
Remoção de Cabelo/métodos , Luz , Adolescente , Adulto , Feminino , Remoção de Cabelo/efeitos adversos , Humanos , Masculino , Resultado do Tratamento , Adulto Jovem
15.
Vasa ; 39(2): 185-8, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20464676

RESUMO

This paper presents a case of an undifferentiated pleomorphic sarcoma/NOS (not otherwise specified; former pleomorphic - storiform malignant fibrous histiocytoma) of the lower leg, of a huge tumor causing ulceration of the cutaneous surface. To improve preoperative conditions, selective transarterial devascularization of the tumor feeders was performed. At operation the tumor was completely ischaemic allowing for clear tumor demarcation with little blood loss during surgery.


Assuntos
Embolização Terapêutica , Sarcoma/terapia , Neoplasias de Tecidos Moles/terapia , Angiografia Digital , Biópsia , Feminino , Humanos , Perna (Membro) , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Terapia Neoadjuvante , Sarcoma/irrigação sanguínea , Sarcoma/diagnóstico , Sarcoma/cirurgia , Neoplasias de Tecidos Moles/irrigação sanguínea , Neoplasias de Tecidos Moles/diagnóstico , Neoplasias de Tecidos Moles/cirurgia , Resultado do Tratamento
16.
Nanotechnology ; 20(32): 325706, 2009 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-19620755

RESUMO

A new method for the measurement of thermal conductivity of electrically conducting single nanowires is presented. First experimental investigations are focused on the thermal conductivity of metallic Pt nanowires with a diameter of (typically) 100 nm and a length of 10 microm. Thermal conductivity data are compared with measurements of electrical conductivity in order to test the Wiedemann-Franz law for metallic nanowires. Compared to the bulk values at room temperature, electrical and thermal conductivities of the nanowire are decreased by a factor of 2.5 and 3.4, respectively. Consequently, the Lorenz number L = lambda/sigmaT = 1.82 x 10(-8) V(2) K(-2) of the nanowire is smaller than the bulk Lorenz number L(bulk) = (pi(2)/3)(k/e)(2) = 2.44 x 10(-8) V(2) K(-2) of metals. Furthermore, the temperature coefficient beta of electrical resistivity is also reduced compared to the bulk value. These decreases of lambda, sigma and beta can be attributed to size effects, mainly caused by grain boundary scattering of electrons.

17.
J Phys Condens Matter ; 21(20): 205301, 2009 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-21825526

RESUMO

We present low temperature resistance R(T) and magnetoresistance measurements for Bi nanowires with diameters between 100 and 500 nm, which are close to being single-crystalline. The nanowires were fabricated by electrochemical deposition in pores of polycarbonate membranes. R(T) varies as T(2) in the low temperature range 1.5 K

18.
J Acoust Soc Am ; 125(5): 3141-5, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19425656

RESUMO

Previous work has demonstrated that a signal receiver based on a limiting form of the Shannon entropy is, in certain settings, more sensitive to subtle changes in scattering architecture than conventional energy-based signal receivers [M. S. Hughes et al., J. Acoust. Soc. Am. 121, 3542-3557 (2007)]. In this paper new results are presented demonstrating further improvements in sensitivity using a signal receiver based on the Renyi entropy.


Assuntos
Entropia , Aumento da Imagem/métodos , Microscopia Acústica/métodos , Algoritmos , Animais , Orelha/patologia , Integrinas/metabolismo , Camundongos , Camundongos Transgênicos , Nanopartículas
19.
Rev Argent Microbiol ; 41(4): 212-4, 2009.
Artigo em Espanhol | MEDLINE | ID: mdl-20085183

RESUMO

Mycoplasma ovis is an obligatory parasite of the erythrocytes from small ruminants (sheep, goat), wherein it causes chronic or acute anaemia. This agent shows worldwide distribution. However, its dispersion is still unknown in Argentina. This work describes an outbreak of mycoplasmosis occurred in January 2007 in a sheep flock from Rosario de la Frontera, Salta, Argentina. Adult sheep became ill with a mortality rate of 17.8%. All blood smears (n = 11) examined by Giemsa stain showed the presence of small basophile bodies characteristic of M. ovis infection, indicating a high prevalence of the infection in the flock. The molecular diagnosis (n = 9) confirmed the findings through the amplification of two fragments from the 16S rRNA gene. This is the third report of M. ovis in Argentina and the first one concomitant with clinical signs at flock level.


Assuntos
Surtos de Doenças/veterinária , Infecções por Mycoplasma/veterinária , Mycoplasma/isolamento & purificação , Doenças dos Ovinos/epidemiologia , Animais , Argentina/epidemiologia , Eritrócitos/microbiologia , Mycoplasma/classificação , Infecções por Mycoplasma/diagnóstico , Infecções por Mycoplasma/epidemiologia , Infecções por Mycoplasma/microbiologia , Filogenia , Reação em Cadeia da Polimerase , Ribotipagem , Ovinos , Doenças dos Ovinos/diagnóstico , Doenças dos Ovinos/microbiologia
20.
J Nanosci Nanotechnol ; 8(11): 5659-66, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19198285

RESUMO

We have developed different electrochemical procedures for the production of gold nanowires with variable and controllable crystallographic and morphological properties using etched ion track templates. The texture of the nanowires is tuned by the variation of the electrodeposition parameters. Potentiostatic plating at low overvoltage provides strongly (110) textured wires for diameters below 100 nm. With the increase in diameter above 100 nm, this texture decreases and the signal from ({111} planes becomes more pronounced. Under reverse pulse deposition conditions, (100) textured wires are generated. The growth mechanism is discussed in detail in terms of the surface energy minimum principle. In addition, wires are shaped in a reliable way from cylindrical to conical geometry by engineering the pore structure in the template.


Assuntos
Cristalização/métodos , Eletroquímica/métodos , Ouro/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Nanotubos/química , Nanotubos/ultraestrutura , Condutividade Elétrica , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície
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