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1.
Phys Rev Lett ; 129(19): 195002, 2022 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36399755

RESUMO

The application of an external 26 Tesla axial magnetic field to a D_{2} gas-filled capsule indirectly driven on the National Ignition Facility is observed to increase the ion temperature by 40% and the neutron yield by a factor of 3.2 in a hot spot with areal density and temperature approaching what is required for fusion ignition [1]. The improvements are determined from energy spectral measurements of the 2.45 MeV neutrons from the D(d,n)^{3}He reaction, and the compressed central core B field is estimated to be ∼4.9 kT using the 14.1 MeV secondary neutrons from the D(T,n)^{4}He reactions. The experiments use a 30 kV pulsed-power system to deliver a ∼3 µs current pulse to a solenoidal coil wrapped around a novel high-electrical-resistivity AuTa_{4} hohlraum. Radiation magnetohydrodynamic simulations are consistent with the experiment.

2.
Artigo em Inglês | MEDLINE | ID: mdl-30136978

RESUMO

Much research has been done regarding how to visualize and interact with observations and attributes of high-dimensional data for exploratory data analysis. From the analyst's perceptual and cognitive perspective, current visualization approaches typically treat the observations of the high-dimensional dataset very differently from the attributes. Often, the attributes are treated as inputs (e.g., sliders), and observations as outputs (e.g., projection plots), thus emphasizing investigation of the observations. However, there are many cases in which analysts wish to investigate both the observations and the attributes of the dataset, suggesting a symmetry between how analysts think about attributes and observations. To address this, we define SIRIUS (Symmetric Interactive Representations In a Unified System), a symmetric, dual projection technique to support exploratory data analysis of high-dimensional data. We provide an example implementation of SIRIUS and demonstrate how this symmetry affords additional insights.

3.
Regul Toxicol Pharmacol ; 97: 88-97, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29894733

RESUMO

Reduced Risk Products (RRPs) do not burn tobacco and produce lower levels of toxicants than in cigarette smoke. The long-term effects of using RRPs on health are difficult to assess in a pre-market setting and a modeling approach is required to quantify harm reduction. The Population Health Impact Model (Weitkunat et al., 2015) follows a hypothetical population of individuals over time, creating their tobacco use histories and, based on these, estimating relative and absolute risks of lung cancer, ischemic heart disease, stroke and chronic obstructive pulmonary disease. Linking the tobacco use to the risk profile allow us to assess how the relative and absolute risks of these diseases vary between individuals aged 20, 30, 40 or 50 at baseline who have never smoked or who initiated smoking at 19 years old and either continued to smoke, quit smoking, or switched to RRPs with varying degrees of harm reduction. The simulations suggest that, for smokers in their 20s-30s quitting, or switching to RRP primarily prevents the accrual of risk, while in their 40s-50s it reduces risk. Though tobacco prevention has been the primary approach to limit smoking-related diseases, RRPs can also substantially reduce risks in individuals who do not quit.


Assuntos
Neoplasias Pulmonares/induzido quimicamente , Isquemia Miocárdica/induzido quimicamente , Doença Pulmonar Obstrutiva Crônica/induzido quimicamente , Acidente Vascular Cerebral/induzido quimicamente , Produtos do Tabaco/efeitos adversos , Uso de Tabaco/efeitos adversos , Adulto , Feminino , Humanos , Neoplasias Pulmonares/epidemiologia , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Isquemia Miocárdica/epidemiologia , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Fatores de Risco , Acidente Vascular Cerebral/epidemiologia , Adulto Jovem
4.
Phys Rev Lett ; 121(24): 242002, 2018 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-30608729

RESUMO

We report the first observation of the parity-violating gamma-ray asymmetry A_{γ}^{np} in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory. A_{γ}^{np} isolates the ΔI=1, ^{3}S_{1}→^{3}P_{1} component of the weak nucleon-nucleon interaction, which is dominated by pion exchange and can be directly related to a single coupling constant in either the DDH meson exchange model or pionless effective field theory. We measured A_{γ}^{np}=[-3.0±1.4(stat)±0.2(syst)]×10^{-8}, which implies a DDH weak πNN coupling of h_{π}^{1}=[2.6±1.2(stat)±0.2(syst)]×10^{-7} and a pionless EFT constant of C^{^{3}S_{1}→^{3}P_{1}}/C_{0}=[-7.4±3.5(stat)±0.5(syst)]×10^{-11} MeV^{-1}. We describe the experiment, data analysis, systematic uncertainties, and implications of the result.

5.
Phytopathology ; 107(12): 1522-1531, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28762287

RESUMO

Incorporating disease resistance into cultivars is a primary focus of modern breeding programs. Resistance to pathogens is often introgressed from landrace or wild individuals with poor fruit quality into commercial-quality cultivars. Sites of multiple disease resistance (MDR) are regions or "hot spots" of the genome with closely linked genes for resistance to different pathogens that could enable rapid incorporation of resistance. An F2-derived F6 recombinant inbred line population from a cross between 'Criollo de Morelos 334' (CMM334) and 'Early Jalapeno' was evaluated in inoculated fruit studies for susceptibility to oomycete and fungal pathogens: Phytophthora capsici, P. nicotianae, Botrytis cinerea, Fusarium oxysporum, F. solani, Sclerotinia sclerotiorum, Alternaria spp., Rhizopus oryzae, R. stolonifer, and Colletotrichum acutatum. All isolates evaluated were virulent on pepper. Significant differences in disease susceptibility were identified among lines for each of the pathogens evaluated. P. capsici was the most virulent pathogen, while R. oryzae and one Sclerotinia isolate were the least virulent. Quantitative trait loci associated with resistance were identified for Alternaria spp. and S. sclerotiorum. Positive correlations in disease incidence were detected between Alternaria spp. and F. oxysporum, F. solani, and C. acutatum, as well as between C. acutatum and Botrytis spp., F. oxysporum, F. solani, and P. capsici. No sites of MDR were identified for pathogens tested; however, positive correlations in disease incidence were detected among pathogens suggesting there may be genetic linkage among resistance genes in CM334 and Early Jalapeno.


Assuntos
Capsicum/imunologia , Resistência à Doença/genética , Fungos/fisiologia , Phytophthora/fisiologia , Doenças das Plantas/imunologia , Locos de Características Quantitativas/genética , Capsicum/genética , Capsicum/microbiologia , Frutas/genética , Frutas/imunologia , Frutas/microbiologia , Ligação Genética , Doenças das Plantas/microbiologia
6.
J Small Anim Pract ; 57(9): 459-64, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27271454

RESUMO

OBJECTIVES: To describe serum C-reactive protein and S100A12 concentrations in dogs with hepatic disease and to determine whether there is a relationship between the concentration of either and the severity of hepatic necroinflammation. METHODS: Serum C-reactive protein and S100A12 concentrations were measured in 46 dogs undergoing hepatic biopsy. Dogs were divided into three groups: congenital portosystemic shunts, chronic hepatitis and hepatic neoplasia. The histological severity of hepatic necroinflammation was scored. RESULTS: C-reactive protein and S100A12 concentrations were greater than the upper limit of the reference intervals in 39 and 26% of dogs, respectively. There was no association of disease group with C-reactive protein (P=0·1733) or S100A12 (P=0·1513) concentrations. There was a positive correlation between serum C-reactive protein concentration and hepatic necroinflammatory activity (rs =0·428, P=0·006). CLINICAL SIGNIFICANCE: Increased serum C-reactive protein and S100A12 concentrations were observed in a subpopulation of dogs with various types of hepatic diseases, suggesting acute-phase inflammation and activation of phagocytic cells, respectively. Dogs with higher hepatic necroinflammatory activity scores tended to have higher serum C-reactive protein concentrations. Further studies are needed to confirm this finding in a larger group of dogs.


Assuntos
Biomarcadores/sangue , Proteínas Sanguíneas/metabolismo , Doenças do Cão/sangue , Hepatopatias/sangue , Proteína S100A12/sangue , Animais , Doenças do Cão/patologia , Cães , Feminino , Masculino , Valor Preditivo dos Testes , Índice de Gravidade de Doença
7.
Rev Sci Instrum ; 86(5): 055101, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-26026552

RESUMO

We present the design, description, calibration procedure, and an analysis of systematic effects for an apparatus designed to measure the rotation of the plane of polarization of a transversely polarized slow neutron beam as it passes through unpolarized matter. This device is the neutron optical equivalent of a crossed polarizer/analyzer pair familiar from light optics. This apparatus has been used to search for parity violation in the interaction of polarized slow neutrons in matter. Given the brightness of existing slow neutron sources, this apparatus is capable of measuring a neutron rotary power of dϕ/dz = 1 × 10(-7) rad/m.

8.
Plant Dis ; 99(12): 1689-1694, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30699514

RESUMO

Boxwood blight caused by Calonectria pseudonaviculata is typically expressed as a foliage disease with aboveground symptoms including defoliation, dieback and formation of dark narrow stem cankers. Whether this pathogen behaves like other Calonectria spp. and has a significant soil phase in the epidemiology of boxwood blight is not known. In this study we observed experimentally that (1) the boxwood blight pathogen consistently forms microsclerotia in artificially inoculated leaves and roots of Buxus spp., (2) soil artificially inoculated with conidia and microsclerotia of this pathogen can cause foliar blight, (3) conidia and microsclerotia can remain viable in soil for up to 3 and at least 40 weeks, respectively (4) and the pathogen can cause crown and root rot to plants only when roots and crowns are directly exposed to relatively high inoculum levels. Our results suggest that C. pseudonaviculata is primarily a foliar pathogen with a potentially epidemiologically significant soil phase.

9.
Surgeon ; 13(1): 19-33, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24206935

RESUMO

BACKGROUND: Survival in oesophageal cancer remains poor with high post-operative recurrence rates. PET/CT was introduced to the Three-Counties Cancer Network (3CCN) in 2006 to detect 'occult' metastatic disease not seen with conventional staging modalities. This study aims to determine whether the introduction of Integrated fluorodeoxyglucose (18F) Positron Emission Tomography (PET/CT) has changed the management, improved survival or reduced the rate of early post-operative recurrence in patients with operable oesophageal cancer. METHODS: A retrospective review was undertaken of all patients diagnosed with oesophageal cancer in the 3CCN from 2005 to 2009. Early recurrence was defined as proven recurrence locally or at a distant site within one year of resection. RESULTS: 725 patients were identified. 200 (27.6%) patients underwent staging PET/CT. PET/CT altered treatment intent in 19 (9.5%) patients. 128 (17.7%) patients underwent oesophageal resection, 90 (70.3%) of which had a staging PET/CT. No significant difference was noted in post-operative mortality (4.4% Vs 5.3%, p = 0.8) or early recurrence where PET/CT was performed when adjusted for age, sex, stage or neo-adjuvant chemotherapy (p = 0.761, OR 1.136[95% CI 0.499-2.585]). PET/CT had no significant effect on survival (log-rank test; Chi-square 0.710, p = 0.4). CONCLUSION: PET/CT has improved the accuracy of oesophageal cancer staging avoiding potentially unnecessary surgery. Ultimately however, its use has had no effect on early recurrence or survival rates. Inaccurate identification of occult metastatic disease prior to the introduction of staging PET/CT does not appear to be the primary cause of early recurrence in patients with oesophageal cancer.


Assuntos
Neoplasias Esofágicas/diagnóstico , Fluordesoxiglucose F18/farmacologia , Recidiva Local de Neoplasia/epidemiologia , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons/métodos , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/cirurgia , Esofagectomia , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Prognóstico , Compostos Radiofarmacêuticos/farmacologia , Estudos Retrospectivos , Taxa de Sobrevida/tendências , Reino Unido/epidemiologia
10.
Br J Pharmacol ; 171(24): 5870-80, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25161074

RESUMO

BACKGROUND AND PURPOSE: Fluoxetine, a selective serotonin reuptake inhibitor, elevates brain concentrations of the neuroactive progesterone metabolite allopregnanolone, an effect suggested to underlie its use in the treatment of premenstrual dysphoria. One report showed fluoxetine to activate the aldo-keto reductase (AKR) component of 3α-hydroxysteroid dehydrogenase (3α-HSD), which catalyses production of allopregnanolone from 5α-dihydroprogesterone. However, this action was not observed by others. The present study sought to clarify the site of action for fluoxetine in elevating brain allopregnanolone. EXPERIMENTAL APPROACH: Adult male rats and female rats in dioestrus were treated with fluoxetine and their brains assayed for allopregnanolone and its precursors, progesterone and 5α-dihydroprogesterone. Subcellular fractions of rat brain were also used to investigate the actions of fluoxetine on 3α-HSD activity in both the reductive direction, producing allopregnanolone from 5α-dihydroprogesterone, and the reverse oxidative direction. Fluoxetine was also tested on these recombinant enzyme activities expressed in HEK cells. KEY RESULTS: Short-term treatment with fluoxetine increased brain allopregnanolone concentrations in female, but not male, rats. Enzyme assays on native rat brain fractions and on activities expressed in HEK cells showed fluoxetine did not affect the AKR producing allopregnanolone from 5α-dihydroprogesterone but did inhibit the microsomal dehydrogenase oxidizing allopregnanolone to 5α-dihydroprogesterone. CONCLUSIONS AND IMPLICATIONS: Fluoxetine elevated allopregnanolone in female rat brain by inhibiting its oxidation to 5α-dihydroprogesterone by a microsomal dehydrogenase. This is a novel site of action for fluoxetine, with implications for the development of new agents and/or dosing regimens to raise brain allopregnanolone.


Assuntos
3-alfa-Hidroxiesteroide Desidrogenase (B-Específica)/antagonistas & inibidores , Encéfalo/efeitos dos fármacos , Fluoxetina/farmacologia , Pregnanolona/metabolismo , Inibidores Seletivos de Recaptação de Serotonina/farmacologia , 3-alfa-Hidroxiesteroide Desidrogenase (B-Específica)/metabolismo , 5-alfa-Di-Hidroprogesterona/metabolismo , Aldeído Redutase/efeitos dos fármacos , Aldeído Redutase/metabolismo , Aldo-Ceto Redutases , Animais , Encéfalo/metabolismo , Feminino , Células HEK293 , Humanos , Masculino , Pregnanolona/biossíntese , Progesterona/metabolismo , Ratos
11.
Dev Biol ; 372(1): 5-16, 2012 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-23010510

RESUMO

Establishment and maintenance of functional stem cells is critical for organ development and tissue homeostasis. Little is known about the mechanisms underlying stem establishment during organogenesis. Drosophila testes are among the most thoroughly characterized systems for studying stem cell behavior, with germline stem cells (GSCs) and somatic cyst stem cells (CySCs) cohabiting a discrete stem cell niche at the testis apex. GSCs and CySCs are arrayed around hub cells that also comprise the niche and communication between hub cells, GSCs, and CySCs regulates the balance between stem cell maintenance and differentiation. Recent data has shown that functional, asymmetrically dividing GSCs are first established at ∼23 h after egg laying during Drosophila testis morphogenesis (Sheng et al., 2009). This process correlates with coalescence of the hub, but development of CySCs from somatic gonadal precursors (SGPs) was not examined. Here, we show that functional CySCs are present at the time of GSC establishment, and that Jak-STAT signaling is necessary and sufficient for CySC maintenance shortly thereafter. Furthermore, hyper-activation of Jak in CySCs promotes expansion of the GSC population, while ectopic Jak activation in the germline induces GSC gene expression in GSC daughter cells but does not prevent spermatogenic differentiation. Together, these observations indicate that, similar to adult testes, Jak-STAT signaling from the hub acts on both GSCs and CySC to regulate their development and differentiation, and that additional signaling from CySCs to the GSCs play a dominant role in controlling GSC maintenance during niche formation.


Assuntos
Diferenciação Celular , Proteínas de Drosophila/genética , Drosophila/embriologia , Drosophila/genética , Janus Quinases/genética , Fatores de Transcrição STAT/genética , Testículo/citologia , Fatores de Transcrição/genética , Animais , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Embrião não Mamífero/metabolismo , Células Germinativas/citologia , Células Germinativas/metabolismo , Janus Quinases/metabolismo , Masculino , Modelos Biológicos , Morfogênese , Fatores de Transcrição STAT/metabolismo , Transdução de Sinais , Nicho de Células-Tronco/genética , Células-Tronco/citologia , Células-Tronco/metabolismo , Testículo/metabolismo , Fatores de Transcrição/metabolismo
12.
Neurotoxicology ; 30(6): 934-40, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19716846

RESUMO

OBJECTIVES: A diagnostic algorithm for clinical manganism was developed to screen all employees at a South African manganese smelter. METHODS: The study design was for all 754 smelter employees in 2006/7 to be screened by an occupational health nurse using nine questions and nine brief neurological examination procedures. More than one symptom, any neurological sign, or blood manganese exceeding 40 microg/l triggered referral for neurological examination by an Occupational Medical Practioner (OMP). Abnormal findings by the OMP triggered referral to a movement disorders specialist neurologist and to a neuropsychologist. Features of parkinsonism and a clinical picture consistent with the scientific literature were used to diagnose manganism. RESULTS: Total manganese dust was mostly within (<5 mg/m(3)) or near (<9 mg/m(3)) the South African Occupational Exposure Limit, with one outlier near 20 mg/m(3). Occupational Health Service problems and uncertainty about the nature of manganism before the full diagnostic algorithm was developed, resulted in 10 referrals who were certified as manganism cases by the state compensation authorities. They were only assessed in the early stages of this screening programme, and never examined by the above specialists. Of 744 employees screened with the full diagnostic algorithm, the nurse referred 152 (20.3%) and the OMP 27 (3.5%) of all those screened respectively. No definite manganism cases were diagnosed, while one (0.13%) employee was found to have possible manganism and another had an indeterminate neurological diagnosis. A sensitivity analysis assuming that all 10 compensated cases were either normal, or alternatively had definite manganism, yielded a prevalence range for definite manganism from 0% to 1.3%. CONCLUSION: Acknowledging possible downward bias when excluding the 10 employees who did not receive the full workup, the true prevalence of definite manganism was likely to be either zero or close to zero.


Assuntos
Monitoramento Ambiental/métodos , Intoxicação por Manganês/diagnóstico , Intoxicação por Manganês/epidemiologia , Exposição Ocupacional/estatística & dados numéricos , Algoritmos , Estudos Transversais , Monitoramento Epidemiológico , Humanos , Exame Neurológico/métodos , Testes Neuropsicológicos , Exposição Ocupacional/efeitos adversos , Prevalência , Medição de Risco , África do Sul/epidemiologia , Inquéritos e Questionários
13.
BMC Evol Biol ; 8: 295, 2008 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-18950531

RESUMO

BACKGROUND: Quantifying the amount of standing genetic variation in fitness represents an empirical challenge. Unfortunately, the shortage of detailed studies of the genetic architecture of fitness has hampered progress in several domains of evolutionary biology. One such area is the study of sexual selection. In particular, the evolution of adaptive female choice by indirect genetic benefits relies on the presence of genetic variation for fitness. Female choice by genetic benefits fall broadly into good genes (additive) models and compatibility (non-additive) models where the strength of selection is dictated by the genetic architecture of fitness. To characterize the genetic architecture of fitness, we employed a quantitative genetic design (the diallel cross) in a population of the seed beetle Callosobruchus maculatus, which is known to exhibit post-copulatory female choice. From reciprocal crosses of inbred lines, we assayed egg production, egg-to-adult survival, and lifetime offspring production of the outbred F1 daughters (F1 productivity). RESULTS: We used the bio model to estimate six components of genetic and environmental variance in fitness. We found sizeable additive and non-additive genetic variance in F1 productivity, but lower genetic variance in egg-to-adult survival, which was strongly influenced by maternal and paternal effects. CONCLUSION: Our results show that, in order to gain a relevant understanding of the genetic architecture of fitness, measures of offspring fitness should be inclusive and should include quantifications of offspring reproductive success. We note that our estimate of additive genetic variance in F1 productivity (CVA=14%) is sufficient to generate indirect selection on female choice. However, our results also show that the major determinant of offspring fitness is the genetic interaction between parental genomes, as indicated by large amounts of non-additive genetic variance (dominance and/or epistasis) for F1 productivity. We discuss the processes that may maintain additive and non-additive genetic variance for fitness and how these relate to indirect selection for female choice.


Assuntos
Besouros/genética , Vigor Híbrido , Preferência de Acasalamento Animal , Seleção Genética , Animais , Cruzamentos Genéticos , Evolução Molecular , Feminino , Variação Genética , Genética Populacional , Genótipo , Padrões de Herança , Modelos Genéticos , Fenótipo , Característica Quantitativa Herdável
14.
Neuroscience ; 148(2): 375-84, 2007 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-17640817

RESUMO

Dehydroepiandrosterone sulfate (DHEAS) has been shown to enhance memory retention in different animal models and in various learning paradigms. In the present study, we investigated the effect of peripherally administered DHEAS on the acquisition, consolidation and retention of memory using a weak version of the one-trial passive avoidance task in day-old chicks. Intraperitoneally administered DHEAS (20 mg/kg) either 30 min before or 30 min and 4.5 h after training on the weakly aversive stimulus, enhanced recall at 24 h following training, suggesting a potentiation of not only the acquisition but also the early and late phases of memory consolidation. In contrast, when DHEAS was administered at 30 min prior to the 24 h retention test there was no memory enhancement, indicating a lack of effect on memory retrieval. Memory recall was unaltered when DHEAS was administered at 30 min before training in a control group trained on a strongly aversive stimulus, confirming memory-specific effects. Interestingly, the memory enhancement appeared to be sex-specific as male chicks showed higher recall than females. These findings provide further evidence that DHEAS enhances memory and may be involved in the temporal cascade of long-term memory formation.


Assuntos
Sulfato de Desidroepiandrosterona/farmacologia , Memória/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Embrião de Galinha , Galinhas , Sulfato de Desidroepiandrosterona/metabolismo , Feminino , Masculino , Fatores Sexuais , Estatísticas não Paramétricas , Fatores de Tempo , Trítio/metabolismo
15.
Plant Dis ; 91(9): 1170-1179, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30780659

RESUMO

We compared photosynthesis and multispectral radiometry (MSR) measurements with visual quality ratings for assessment of feeding injury to creeping bentgrass caused by the lance nematode (Hoplolaimus galeatus) using artificially infested microplots and a naturally infested putting green. Nematode feeding resulted in negative visual and MSR effects on creeping bentgrass in microplots. Visual quality ratings were correlated more consistently with nematode densities than either individual MSR variables or factor models of MSR variables. Threshold estimates for H. galeatus population densities associated with unacceptable bentgrass quality in microplots varied widely by month and year. Similarly, the relationship between H. galeatus population density and turf health indicators (including MSR measurements, visual ratings, and net photosynthetic rate) varied with cultivar and management practice (irrigation frequency and mowing height) in the naturally infested putting green. Notably, negative effects of nematode feeding were not consistently associated with more stressful management practices, suggesting that stress avoidance is not a reliable deterrent to H. galeatus damage in creeping bentgrass. Damage thresholds for this nematode-host association are dynamic and should be used with caution.

16.
Endocrinology ; 147(1): 179-90, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16223859

RESUMO

Steroids in the brain arise both from local synthesis and from peripheral sources and have a variety of effects on neuronal function. However, there is little direct chemical evidence for the range of steroids present in brain or of the pathways for their synthesis and inactivation. This information is a prerequisite for understanding the regulation and function of brain steroids. After extraction from adult male rat brain, we have fractionated free steroids and their sulfate esters and then converted them to heptafluorobutyrate or methyloxime-trimethylsilyl ether derivatives for unequivocal identification and assay by gas chromatography analysis and selected ion monitoring mass spectrometry. In the free steroid fraction, corticosterone, 3alpha,5alpha-tetrahydrodeoxycorticosterone, testosterone, and dehydroepiandrosterone were found in the absence of detectable precursors usually found in endocrine glands, indicating peripheral sources and/or alternative synthetic pathways in brain. Conversely, the potent neuroactive steroid 3alpha,5alpha-tetrahydroprogesterone (allopregnanolone) was found in the presence of its precursors pregnenolone, progesterone, and 5alpha-dihydroprogesterone. Furthermore, the presence of 3beta-, 11beta-, 17alpha-, and 20alpha-hydroxylated metabolites of 3alpha,5alpha-tetrahydroprogesterone implicated possible inactivation pathways for this steroid. The 20alpha-reduced metabolites could also be found for pregnenolone, progesterone, and 5alpha-dihydroprogesterone, introducing a possible regulatory diversion from the production of 3alpha,5alpha-tetrahydroprogesterone. In the steroid sulfate fraction, dehydroepiandrostrone sulfate was identified but not pregnenolone sulfate. Although pharmacologically active, identification of the latter appears to be an earlier methodological artifact, and the compound is thus of doubtful physiological significance in the adult brain. Our results provide a basis for elucidating the origins and regulation of brain steroids.


Assuntos
Androgênios/análise , Química Encefálica , Hormônios Esteroides Gonadais/análise , Progesterona/análise , Androgênios/isolamento & purificação , Animais , Cromatografia Gasosa-Espectrometria de Massas , Hormônios Esteroides Gonadais/isolamento & purificação , Masculino , Progesterona/isolamento & purificação , Ratos , Ratos Sprague-Dawley
17.
Plant Dis ; 90(1): 44-50, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30786473

RESUMO

The effects of management practices and nematode population density on the seasonal fluctuationsin lance nematode (Hoplolaimus galeatus) populations in creeping bentgrass were studiedin a naturally infested experimental putting green and in artificially infested microplots. In general, H. galeatus populations increased from late spring through midsummer, declined in August, and increased again in the fall. Population increase in microplots was strongly density dependent, with final population densities inversely proportional to inoculum levels. Ectoparasitic populationsof H. galeatus in both studies were composed of adults and juveniles, whereas endoparasiticpopulations were almost exclusively juveniles. H. galeatus populations in the naturallyinfested site were aggregated spatially, but the aggregation was not temporally stable. Nematodepopulations were not affected by bentgrass cultivar selection or irrigation frequency.

18.
Genes Brain Behav ; 4(4): 209-28, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15924554

RESUMO

The midbrain dopamine system mediates normal and pathologic behaviors related to motor activity, attention, motivation/reward and cognition. These are complex, quantitative traits whose variation among individuals is modulated by genetic, epigenetic and environmental factors. Conventional genetic methods have identified several genes important to this system, but the majority of factors contributing to the variation remain unknown. To understand these genetic and environmental factors, we initiated a study measuring 21 behavioral and neurochemical traits in 15 common inbred mouse strains. We report trait data, heritabilities and genetic and non-genetic correlations between pheno-types. In general, the behavioral traits were more heritable than neurochemical traits, and both genetic and non-genetic correlations within these trait sets were high. Surprisingly, there were few significant correlations between the behavioral and the individual neurochemical traits. However, striatal serotonin and one measure of dopamine turnover (DOPAC/DA) were highly correlated with most behavioral measures. The variable accounting for the most variation in behavior was mouse strain and not a specific neurochemical measure, suggesting that additional genetic factors remain to be determined to account for these behavioral differences. We also report the prospective use of the in silico method of quantitative trait loci (QTL) analysis and demonstrate difficulties in the use of this method, which failed to detect significant QTLs for the majority of these traits. These data serve as a framework for further studies of correlations between different midbrain dopamine traits and as a guide for experimental cross designs to identify QTLs and genes that contribute to these traits.


Assuntos
Química Encefálica/genética , Mapeamento Cromossômico/métodos , Bases de Dados Genéticas , Camundongos Endogâmicos/genética , Atividade Motora/genética , Animais , Monoaminas Biogênicas/metabolismo , Cromatografia Líquida de Alta Pressão , Dopamina/fisiologia , Eletroquímica , Variação Genética , Habituação Psicofisiológica/genética , Masculino , Mesencéfalo/metabolismo , Camundongos , Análise Multivariada , Neostriado/química , Neostriado/metabolismo , Fenótipo , Polimorfismo de Nucleotídeo Único , Análise de Componente Principal
19.
J Viral Hepat ; 12(1): 67-73, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15655050

RESUMO

One hundred and thirty-one post-liver transplantation patients with chronic hepatitis B and failing lamivudine therapy with detectable serum hepatitis B virus (HBV) deoxyribonucleic acid by hybridization assays or > or =1 x 10(6) copies/mL by polymerase chain reaction, and elevated alanine transaminase levels despite continuous lamivudine, were enrolled in an open-label study of adefovir dipivoxil. The B and C domains of HBV polymerase were sequenced for baseline samples to determine the presence of lamivudine resistance mutations. The results showed that 98% of the samples had tyrosine-methionine-aspartate-aspartate (YMDD) mutations, indicating a strong correlation between the above clinical definition of lamivudine treatment failure and the presence of YMDD mutations. In addition to the rtM204V/I and the rtL180M mutations, the mutation rtV173L was identified in 19% of patients. Four major patterns of lamivudine-resistant HBV were identified: rtL180M + rtM204V (60%), rtV173L + rtL180M + rtM204V (19%), rtM204I (9%) and rtL180M + rtM204I (9%). Treatment with adefovir dipivoxil showed similar antiviral efficacy in patients with lamivudine-resistant virus from all four patterns.


Assuntos
Adenina/análogos & derivados , Adenina/uso terapêutico , Antivirais/uso terapêutico , Hepatite B Crônica/tratamento farmacológico , Lamivudina/uso terapêutico , Organofosfonatos/uso terapêutico , Alanina Transaminase/sangue , Farmacorresistência Viral , Feminino , Produtos do Gene pol/genética , Vírus da Hepatite B/genética , Hepatite B Crônica/sangue , Hepatite B Crônica/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Tempo de Protrombina , Albumina Sérica/análise , Carga Viral
20.
J Environ Radioact ; 76(1-2): 207-23, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15245849

RESUMO

The rehabilitation of the former nuclear test site at Maralinga involved (among other processes) the removal of contaminated soil from an area of approximately 2.5 km2. The two most stringent rehabilitation criteria required measurements to ensure that no radioactive particle exceeding 100 kBq of 241Am activity, and no area of 1 ha exceeding 3 kBq/m2 of 241Am activity, remained in the rehabilitated area. The project timetable required that the area be scanned at the rate of approximately 3 ha/day. Two vehicle-mounted detection systems were developed and constructed to obtain the necessary measurements in the available timeframe. The scientific basis for the designs are presented, together with details of the selected equipment and technical solutions found. The performance of this equipment in the field is discussed in terms of both its scientific and technical operation. Based on the experience gained at Maralinga, improved versions of this equipment were produced under contract for the People's Republic of China.


Assuntos
Monitoramento Ambiental/instrumentação , Guerra Nuclear , Poluentes Radioativos do Solo/análise , Amerício/análise , China , Poluição Ambiental/prevenção & controle , Desenho de Equipamento , Veículos Automotores , Plutônio/análise , Radioisótopos/análise
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