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1.
Forensic Sci Int ; 349: 111771, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37385158

RESUMO

Radiocarbon dating is a useful tool in the examination of unknown human remains. Recent studies have shown that the analysis of hair and nail samples can provide a highly accurate estimation of the year of death (YOD). However, little research has examined factors that may influence the uptake and storage of 14C in these tissues, such as diet, or the use of beauty products. This study measured the level of 14C in human hair and nail samples collected from living individuals to determine whether diet, and the use of hair dye or nail polish, has a significant impact on the estimation of YOD. The results of this study showed that diet did not appear to impact the radiocarbon content in human hair and nail, and thus should not be considered a limitation when analysing samples obtained from unidentified human remains. The use of nail polish, and in the majority of cases, hair dye, did not significantly impact the 14C concentration in nails and hair. While the results of this study are preliminary, they suggest that in most cases, both hair and nail can be successfully analysed using radiocarbon dating to estimate an individual's YOD. However, best practice should involve the analysis of multiple tissue types, to minimise any error that may be introduced as a result of the decedent's use of beauty products.


Assuntos
Bombas (Dispositivos Explosivos) , Tinturas para Cabelo , Humanos , Unhas , Restos Mortais , Dieta , Cabelo
2.
Folia Microbiol (Praha) ; 68(6): 823-833, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37118368

RESUMO

In the constant search for new pharmacological compounds, molecular hybridisation is a well-known technique whereby two or more known pharmacophoric subunits are combined to create a new "hybrid" compound. This hybrid is expected to maintain the characteristics of the original compounds whilst demonstrating improvements to their pharmacological action. Accordingly, we report here a series of molecular hybrid compounds based upon eugenol and chloramphenicol pharmacophores. The hybrid compounds were screened for their in vitro antimicrobial potential against Gram-negative and Gram-positive bacteria and also rapidly growing mycobacteria (RGM). The results highlight that the antimicrobial profiles of the hybrid compounds improve in a very clear fashion when moving through the series. The most prominent results were found when comparing the activity of the hybrid compounds against some of the multidrug-resistant clinical isolates of Pseudomonas aeruginosa, methicillin-resistant clinical isolates of Staphylococcus aureus (MRSA) and clinical isolates of rapidly growing mycobacteria.


Assuntos
Anti-Infecciosos , Staphylococcus aureus Resistente à Meticilina , Cloranfenicol/farmacologia , Eugenol/farmacologia , Farmacóforo , Anti-Infecciosos/farmacologia , Staphylococcus aureus , Antibacterianos/uso terapêutico , Testes de Sensibilidade Microbiana
3.
Forensic Sci Int ; 341: 111480, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36257096

RESUMO

The radiocarbon (14C) analysis of skeletonised human remains can provide vital information regarding the time since death. This study analysed the 14C content in both cortical and trabecular bone from the femur and rib of 18 human remains donated to the Australian Facility for Taphonomic Experimental Research. To determine the most appropriate bone to sample for 14C analysis when estimating the time since death, differences in turnover time between the bone types, and the difference between environmental 14C during the year of death (YOD) and the level of 14C found within the bone (i.e., the lag time) were examined. Overall, the average lag time for all donors was 25 years, with the cortical bone from femur samples providing the largest lag time (39 years) and the trabecular bone from rib samples containing the lowest level of 14C (most modern), with an average lag time of 13 years. The results of this study suggest that in cases of unidentified human remains, the analysis of trabecular bone from a rib may be preferred sample, as this bone contains the most recent 14C, and can provide an estimate of both the time since death, and a broad approximation of YOD.


Assuntos
Restos Mortais , Osso e Ossos , Humanos , Radioisótopos de Carbono/análise , Austrália , Osso e Ossos/química , Fêmur/química
4.
J Athl Train ; 57(5): 464-469, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35230443

RESUMO

CONTEXT: Cold-water immersion (CWI) is the best treatment for patients with exertional heat stroke (EHS), and rectal temperature (Trec) cooling rates may differ between sexes. Previous authors have suggested that the body surface area (BSA):lean body mass (LBM) ratio is the largest factor affecting CWI Trec cooling rates in men with hyperthermia; this has never been confirmed in women with hyperthermia. OBJECTIVE: To examine whether the BSA:LBM ratio and other anthropometric characteristics affect Trec cooling rates in women with hyperthermia. DESIGN: Cross-sectional study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Sixteen women were placed in either a low BSA:LBM ratio (LOW; n = 8; age = 22 ± 1 years, height = 166.8 ± 6.0 cm, mass = 64.1 ± 4.5 kg, BSA:LBM ratio = 3.759 ± 0.214 m2/kg·102) or high BSA:LBM ratio (HIGH; n = 8; age = 22 ± 2 years, height = 162.7 ± 8.9 cm, mass = 65.8 ± 12.7 kg, BSA:LBM ratio = 4.161 ± 0.232 m2/kg·102) group. INTERVENTION(S): On day 1, we measured physical characteristics using dual-energy x-ray absorptiometry, and participants completed a maximal oxygen consumption test. On day 2, participants walked at 4.8 km/h for 3 minutes and then ran at 80% of their predetermined maximal oxygen consumption for 2 minutes in the heat (temperature = ∼40°C, relative humidity = 40%). This sequence was repeated until Trec reached 39.5°C. Then they underwent CWI (temperature = ∼10°C) until Trec was 38°C. MAIN OUTCOME MEASURE(S): Rectal temperature and CWI cooling rates. RESULTS: The groups had different BSA:LBM ratios (P = .001), LBM (LOW: 45.8 ± 3.0 kg; HIGH: 41.0 ± 5.1 kg; P = .02), and body fat percentages (LOW: 25.7% ± 5.0%; HIGH: 33.7% ± 6.3%; P = .007) but not different BSA (LOW: 1.72 ± 0.08 m2; HIGH: 1.70 ± 0.16 m2; P = .40) or body mass index (LOW: 23.1 ± 2.1; HIGH: 24.9 ± 4.7; P = .17). Despite differences in several physical characteristics, Trec cooling rates were excellent but comparable (LOW: 0.26°C/min ± 0.09°C/min; HIGH: 0.27°C/min ± 0.07°C/min; P = .39). The BSA:LBM ratio (r = 0.14, P = .59), BSA (r = -0.01, P = .97), body mass index (r = 0.37, P = .16), and body fat percentage (r = 0.29, P = .28), LBM (r = -0.10, P = .70) were not correlated with Trec cooling rates. CONCLUSIONS: Body anthropometric characteristics did not affect CWI Trec cooling rates in women with hyperthermia. Therefore, clinicians need not worry that anthropometric characteristics might slow CWI treatment in women with severe hyperthermia.


Assuntos
Exercício Físico , Hipertermia Induzida , Adulto , Temperatura Corporal , Regulação da Temperatura Corporal , Temperatura Baixa , Estudos Transversais , Feminino , Temperatura Alta , Humanos , Imersão , Masculino , Temperatura , Água , Adulto Jovem
5.
Psychol Trauma ; 14(4): 688-695, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34498900

RESUMO

OBJECTIVES: Emotion dysregulation theoretically and empirically explains the link between posttraumatic stress disorder (PTSD) and posttrauma reckless and self-destructive behaviors (RSDBs). METHOD: The current study uniquely examined the role of emotion dysregulation in the association between the four heterogeneous PTSD clusters (intrusions, avoidance, negative alterations in cognitions and mood [NACM], and alterations in arousal and reactivity [AAR]) and an overall measure of posttrauma RSDBs. Trauma-exposed participants (n = 411) completed self-report measures assessing PTSD symptoms (PTSD Checklist for DSM-5), emotion dysregulation (Difficulties in Emotion Regulation Scale-16), and engagement in RSDBs (Posttrauma Risky Behaviors Questionnaire). RESULTS: Direct and indirect effects were examined using PROCESS Model 4. The bias-corrected bootstrap revealed a significant indirect effect of emotion dysregulation in posttrauma RSDBs' relation with PTSD's intrusions (B = -.13, SE = .04, 95% CI [-.23, -.06]), avoidance (B =.15, SE =.07, 95% CI [.04, .33]), NACM (B =.17, SE =.05, 95% CI [.09, .27]), and AAR (B =.14, SE =.05, 95% CI [.05, .27]). CONCLUSIONS: Emotion dysregulation explained associations between the severity of each PTSD symptom cluster and overall posttrauma RSDBs. PTSD treatments targeting emotion dysregulation may help to reduce posttrauma RSDBs for trauma-exposed individuals. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Regulação Emocional , Comportamento Autodestrutivo , Transtornos de Estresse Pós-Traumáticos , Manual Diagnóstico e Estatístico de Transtornos Mentais , Humanos , Comportamento Autodestrutivo/psicologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Síndrome
6.
J Forensic Leg Med ; 85: 102275, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34794085

RESUMO

When human remains are discovered, confirming the identification of the decedent is the first part of the forensic medical investigation. In cases where the remains are skeletonised or badly decomposed, differential preservation often increases the difficulty of this task. Bomb pulse dating, which directly compares levels of 14 C within human tissues to atmospheric levels, can provide an estimate of the year of death, which may assist in the identification process. This study measured the 14 C content in samples of hair, nail and puparia collected from donors at the Australian Facility for Taphonomic Experimental Research (AFTER). The radiocarbon results demonstrated that the nail samples provided the most accurate year of death estimation, with 91% correctly predicting YOD, closely followed by hair, with a 79% correct prediction rate, with both hair and nails having a lag time of 0-1 years. This is consistent with the time taken for atmospheric CO 2 to enter the food chain, and be taken in by humans. Puparia was found to have the highest levels of 14 C, and was the least consistent with the actual YOD (46% correct). However, predicted YOD ranges were still within 4 years of the actual YOD. Based on the results of this study, hair, nail and puparia should be considered as useful samples to obtain accurate estimates for YOD using bomb pulse dating.


Assuntos
Bombas (Dispositivos Explosivos) , Datação Radiométrica , Austrália , Radioisótopos de Carbono/análise , Humanos , Unhas/química
7.
J Behav Ther Exp Psychiatry ; 66: 101516, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31634724

RESUMO

BACKGROUND AND OBJECTIVES: Although trauma research and therapy primarily focus on traumatic memories, recent evidence indicates positive memory processes play a role in the etiology/maintenance of posttraumatic stress disorder (PTSD) symptom severity. We examined the effects of a novel positive memory processing technique on PTSD symptom severity, depression symptom severity, affect, posttrauma cognitions, and self-esteem. METHODS: Sixty-five trauma-exposed participants were randomly assigned to one of three conditions (narrating/processing vs. writing/processing two specific positive memories, or a time-matched control) and completed self-report measures pre- and post-task (T0). About one week later, participants repeated their assigned task condition and completed self-report measures pre- and post-task (T1). We conducted mixed ANOVAs to examine the impact of the technique on study variables over time. RESULTS: The narrating condition had significant decreases in PTSD symptom severity, posttrauma cognitions, and negative affect from T0 pre-task to T1 post-task; and significant increases in positive affect from T0 pre-to-post-task and from T1 pre-to-post-task. The writing condition had significant increases in positive affect from T0 pre-to-post-task, but a significant decrease from T0 post-task to T1 post-task; and significant decreases in negative affect from T0 pre-to-post-task with an increase from T0 post-task to T1 post-task. LIMITATIONS: Use of self-report measures, non-clinical convenience sample with less gender/ethnic/racial diversity, small sample size, methodological differences in time frames for measures, and no examination of follow-up effects. CONCLUSIONS: Narrating and processing specific positive memories had a beneficial impact on PTSD symptom severity, posttrauma maladaptive cognitions, and affect; such results provide an impetus to examine positive memory interventions in trauma clinical work.


Assuntos
Memória Episódica , Saúde Mental , Rememoração Mental , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Adolescente , Adulto , Afeto , Cognição , Depressão/diagnóstico , Feminino , Humanos , Masculino , Narração , Autorrelato , Estudantes , Redação , Adulto Jovem
8.
Int J Exerc Sci ; 12(4): 1138-1148, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31839848

RESUMO

This study determined the relationship of core stability with power production, agility, and dynamic stability of collegiate lacrosse players and whether core stability is more evident in these performance variables in either males or females. Twenty male and female collegiate lacrosse players (20.3 ± 1.0 years, 173.2 ± 11.8 cm, 72.6 ± 13.0 kg) performed the pro-agility shuttle, the countermovement jump (CMJ), the Star Excursion Balance Test (SEBT), and prone, right lateral, and left lateral planks on two sessions-familiarization and testing. Independent T-tests were used to compare sexes. SPSS 24.0 was used; significance was accepted at p < 0.05. Pearson correlations were used to compare the relationship of core stability to the performance variables in participants. There was a significant relationship found between the prone plank and pro-agility shuttle in all participants (r = -0.50). No significant relationships were found between core stability and performance variables. A significant difference was found in the pro-agility shuttle (p = 0.001) and the CMJ (p = 0.001) but not in core stability or dynamic stability. Agility, power production, and dynamic stability were not related to core stability in neither male or female lacrosse players. There were no significant differences in core stability and dynamic stability between males and females. A significant difference was found in dynamic stability in the SEBT right leg and left leg composite scores between sexes. From these results, it is suggested that core stability may not directly influence the performance variables in collegiate male and female lacrosse players.

9.
Phys Rev Lett ; 122(13): 131301, 2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-31012624

RESUMO

The scattering of dark matter (DM) particles with sub-GeV masses off nuclei is difficult to detect using liquid xenon-based DM search instruments because the energy transfer during nuclear recoils is smaller than the typical detector threshold. However, the tree-level DM-nucleus scattering diagram can be accompanied by simultaneous emission of a bremsstrahlung photon or a so-called "Migdal" electron. These provide an electron recoil component to the experimental signature at higher energies than the corresponding nuclear recoil. The presence of this signature allows liquid xenon detectors to use both the scintillation and the ionization signals in the analysis where the nuclear recoil signal would not be otherwise visible. We report constraints on spin-independent DM-nucleon scattering for DM particles with masses of 0.4-5 GeV/c^{2} using 1.4×10^{4} kg day of search exposure from the 2013 data from the Large Underground Xenon (LUX) experiment for four different classes of mediators. This analysis extends the reach of liquid xenon-based DM search instruments to lower DM masses than has been achieved previously.

10.
Sci Data ; 5: 180088, 2018 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-29809175

RESUMO

The last deglacial was an interval of rapid climate and sea-level change, including the collapse of large continental ice sheets. This database collates carefully assessed sea-level data from peer-reviewed sources for the interval 0 to 25 thousand years ago (ka), from the Last Glacial Maximum to the present interglacial. In addition to facilitating site-specific reconstructions of past sea levels, the database provides a suite of data beyond the range of modern/instrumental variability that may help hone future sea-level projections. The database is global in scope, internally consistent, and contains U-series and radiocarbon dated indicators from both biological and geomorpohological archives. We focus on far-field data (i.e., away from the sites of the former continental ice sheets), but some key intermediate (i.e., from the Caribbean) data are also included. All primary fields (i.e., sample location, elevation, age and context) possess quantified uncertainties, which-in conjunction with available metadata-allows the reconstructed sea levels to be interpreted within both their uncertainties and geological context.

11.
Phys Rev Lett ; 118(25): 251302, 2017 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-28696768

RESUMO

We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5 kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41} cm^{2} (σ_{p}=5×10^{-40} cm^{2}) at 35 GeV c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

12.
Phys Rev Lett ; 118(26): 261301, 2017 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-28707937

RESUMO

The first searches for axions and axionlike particles with the Large Underground Xenon experiment are presented. Under the assumption of an axioelectric interaction in xenon, the coupling constant between axions and electrons g_{Ae} is tested using data collected in 2013 with an exposure totaling 95 live days ×118 kg. A double-sided, profile likelihood ratio statistic test excludes g_{Ae} larger than 3.5×10^{-12} (90% C.L.) for solar axions. Assuming the Dine-Fischler-Srednicki-Zhitnitsky theoretical description, the upper limit in coupling corresponds to an upper limit on axion mass of 0.12 eV/c^{2}, while for the Kim-Shifman-Vainshtein-Zhakharov description masses above 36.6 eV/c^{2} are excluded. For galactic axionlike particles, values of g_{Ae} larger than 4.2×10^{-13} are excluded for particle masses in the range 1-16 keV/c^{2}. These are the most stringent constraints to date for these interactions.

13.
J Environ Radioact ; 178-179: 349-353, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28526526

RESUMO

A slice from a Porites Lutea coral core collected inside the Enewetak Atoll lagoon, within 15 km of all major nuclear tests conducted at the atoll, was analysed for 236U, 239Pu and 240Pu over the time interval 1952-1964 using a higher time resolution than previously reported for a parallel slice from the same core. In addition two sediment samples from the Koa and Oak craters were analysed. The strong peaks in the concentrations of 236U and 239Pu in the testing years are confirmed to be considerably wider than the flushing time of the lagoon. This is likely due to the growth mechanism of the coral. Following the last test in 1958 atom concentrations of both 236U and 239Pu decreased from their peak values by more than 95% and showed a seasonal signal thereafter. Between 1959 and 1964 the weighted average of the 240Pu/239Pu atom ratio is 0.124 ± 0.008 which is similar to that in the lagoon sediments (0.129 ± 0.006) but quite distinct from the global fallout value of ∼0.18. This, and the high 239,240Pu and 236U concentrations in the sediments, provides clear evidence that the post-testing signal in the coral is dominated by remobilisation of the isotopes from the lagoon sediments rather than from global fallout.


Assuntos
Armas Nucleares , Plutônio/análise , Monitoramento de Radiação , Cinza Radioativa/análise , Urânio/análise , Poluentes Radioativos da Água/análise
14.
J Environ Radioact ; 165: 197-205, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27764678

RESUMO

A comprehensive series of nuclear tests were carried out by the United States at Enewetak Atoll in the Marshall Islands, especially between 1952 and 1958. A Porites Lutea coral that was growing in the Enewetak lagoon within a few km of all of the high-yield tests contains a continuous record of isotopes, which are of interest (e.g. 14C, 236U, 239,240Pu) through the testing period. Prior to the present work, 14C measurements at ∼2-month resolution had shown pronounced peaks in the Δ14C data that coincided with the times at which tests were conducted. Here we report measurements of 236U and 239,240Pu on the same coral using accelerator mass spectrometry, and again find prominent peaks in the concentrations of these isotopes that closely follow those in 14C. Consistent with the 14C data, the magnitudes of these peaks do not, however, correlate well with the explosive yields of the corresponding tests, indicating that smaller tests probably contributed disproportionately to the debris that fell in the lagoon. Additional information about the different tests can also be obtained from the 236U/239Pu and 240Pu/239Pu ratios, which are found to vary dramatically over the testing period. In particular, the first thermonuclear test, Ivy-Mike, has characteristic 236U/239Pu and 240Pu/239Pu signatures which are diagnostic of the first arrival of nuclear test material in various archives.


Assuntos
Antozoários/química , Plutônio/análise , Monitoramento de Radiação , Poluentes Radioativos da Água/análise , Animais , Micronésia , Armas Nucleares , Cinza Radioativa/análise
15.
J. bras. patol. med. lab ; 51(3): 162-165, May-Jun/2015. tab
Artigo em Inglês | LILACS | ID: lil-753108

RESUMO

ABSTRACT The present study aimed to genotypically and phenotypically characterize clinical isolates of carbapenem-resistant Enterobacteriaceae collected from inpatients at the University Hospital of Santa Maria, during seven months. Among the clinical isolates subjected to the modified Hodge test (MHT), 62.5% were positive, indicating possible production of carbapenemase. Polymerase chain reaction (PCR) demonstrated that blaKPC was the most frequently found gene (31%), followed by blaIMP (12.5%). Combined use of the methods is needed to identify carbapenem resistance in enterobacteria to prevent their spread and control the infections caused by these organisms.


RESUMO Objetivou-se caracterizar fenotípica e genotipicamente isolados clínicos de enterobactérias resistentes aos carbapenêmicos (CRE) provenientes do Hospital Universitário de Santa Maria (RS). Entre os isolados clínicos submetidos ao teste modificado de Hodge (MHT), 62,5% apresentaram positividade, indicando possível produção de carbapenemase. A reação em cadeia da polimerase (PCR) demonstrou que o blaKPC foi o gene mais encontrado (31%), seguido de blaIMP (12,5%). O uso conjunto de distintas metodologias faz-se necessário para identificar a resistência aos carbapenêmicos produzida pelas enterobactérias, de modo a auxiliar o controle de infecção prevenindo a disseminação desses microrganismos.

16.
J Hum Evol ; 69: 91-109, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24636733

RESUMO

Since the late 1980s, northern Iberia has yielded some of the earliest radiocarbon dated Aurignacian assemblages in Western Europe, probably produced by anatomically modern humans (AMHs). This is at odds with its location furthest from the likely eastern entry point of AMHs, and has also suggested to some that the Châtelperronian resulted from cultural transfer from AMHs to Neanderthals. However, the accuracy of the early chronology has been extensively disputed, primarily because of the poor association between the dated samples and human activity. Here, we test the chronology of three sites in northern Iberia, L'Arbreda, Labeko Koba and La Viña, by radiocarbon dating ultrafiltered collagen from anthropogenically modified bones. The published dates from Labeko Koba are shown to be significant underestimates due to the insufficient removal of young contaminants. The early (c.44 ka cal BP [thousands of calibrated years before present]) Aurignacian chronology at L'Arbreda cannot be reproduced, but the reason for this is difficult to ascertain. The existing chronology of La Viña is found to be approximately correct. Together, the evidence suggests that major changes in technocomplexes occurred contemporaneously between the Mediterranean and Atlantic regions of northern Iberia, with the Aurignacian appearing around 42 ka cal BP, a date broadly consistent with the appearance of this industry elsewhere in Western Europe.


Assuntos
Arqueologia , Osso e Ossos/química , Cronologia como Assunto , Mamíferos , Animais , Evolução Biológica , Humanos , Datação Radiométrica , Espanha
17.
Pediatr Surg Int ; 30(6): 677-9, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24668180

RESUMO

Allgrove syndrome is a rare genetic disorder typically manifested by alacrima, achalasia, and adrenal insufficiency, and is one of the rare causes of achalasia in infants. While the gold standard for achalasia treatment in adults is an esophageal myotomy with fundoplication, a standard treatment for infantile achalasia remains undetermined due to the low number of reported cases and rarity of the disease in this age group. We report a 7.7 kg infant with achalasia secondary to Allgrove syndrome who was successfully treated by Heller myotomy and simultaneous Toupet fundoplication. This case represents one of the smallest patients to ever be treated for achalasia and highlights the role that primary surgical therapy may have for the infantile variant of the disease.


Assuntos
Insuficiência Adrenal/cirurgia , Acalasia Esofágica/cirurgia , Insuficiência Adrenal/diagnóstico por imagem , Acalasia Esofágica/diagnóstico por imagem , Feminino , Fundoplicatura , Humanos , Lactente , Recém-Nascido , Laparoscopia , Radiografia
18.
Neuropsychologia ; 51(11): 2194-201, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23911779

RESUMO

Planning, the decomposition of an ultimate goal into a number of sub-goals is critically dependent upon fronto-striatal dopamine (DA) levels. Here, we examined the extent to which the val158met polymorphism in the catechol O-methyltransferase (COMT) gene, which is thought to primarily alter cortical DA levels, affects performance and fronto-parietal activity during a planning task (Tower of London). COMT genotype was found to modulate activity in the left superior posterior parietal cortex (SPC) during planning, relative to subtracting, trials. Specifically, left SPC blood oxygenation level-dependent (BOLD) response was reduced in groups with putatively low or high cortical DA levels (COMT homozygotes) relative to those with intermediate cortical DA levels (COMT heterozygotes). These set of results are argued to occur either due to differences in neuronal processing in planning (and perhaps subtracting) caused by the COMT genotype and/or the cognitively heterogeneous nature of the TOL, which allows different cognitive strategies to be used whilst producing indistinguishable behavioural performance in healthy adults. The implications of this result for our understanding of COMT's effect on cognition in health and disease are discussed.


Assuntos
Catecol O-Metiltransferase/genética , Córtex Cerebral/fisiologia , Dopamina/metabolismo , Resolução de Problemas/fisiologia , Idoso , Catecol O-Metiltransferase/metabolismo , Córtex Cerebral/metabolismo , Feminino , Neuroimagem Funcional , Genótipo , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Polimorfismo de Nucleotídeo Único , Tempo de Reação/fisiologia
19.
Cereb Cortex ; 23(2): 361-9, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22351648

RESUMO

A key mechanism by which the prefrontal cortex (PFC) supports goal-oriented behaviors is attentional set formation: the formation and maintenance of an attentional bias toward relevant features. It has previously been proposed that a common single nucleotide polymorphism (val158met) in the gene that codes for the catechol O-methyltransferase (COMT) enzyme may affect an individual's ability to form and maintain an attentional set by modulating PFC dopamine (DA) levels. Here, we present data from a functional magnetic resonance imaging study that investigated the effect of this polymorphism on the tendency for older adults to display set-like behavior, and we compare these results to preexisting data from Parkinson's Disease (PD) patients. Our results demonstrate that putatively different levels of PFC DA predict both attentional set formation and right dorsolateral PFC (DLPFC) activation. More specifically, while for PD patients, val homozygotes showed heightened DLPFC activation and increased set-like behavior, for healthy older adults, the opposite pattern of results was observed. This interaction between COMT genotype and PD accords well with previous studies that have shown an excess of DA in the PFC in early PD patients and, furthermore, supports the hypothesis that there is an inverted-U shaped functional relationship between PFC DA levels and attentional set formation.


Assuntos
Catecol O-Metiltransferase/genética , Cognição/fisiologia , Dopamina/metabolismo , Córtex Pré-Frontal/metabolismo , Idoso , Atenção/fisiologia , Dopamina/genética , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/genética , Doença de Parkinson/psicologia , Polimorfismo de Nucleotídeo Único , Córtex Pré-Frontal/química
20.
J Appl Microbiol ; 110(4): 893-902, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21214696

RESUMO

AIMS: This study aimed to assess the contamination risk of Escherichia coli in commercial lettuce grown under three different irrigation systems (overhead sprinkler, subsurface drip and surface furrow). METHODS AND RESULTS: Three replicated field trials were conducted. In an initial trial, we consistently observed higher mesophilic bacteria counts under sprinkler irrigation but visual quality was found to be dependent on the water potential of leaves at harvest. Further, in the other two trials, E. coli K-12 strains LMM1010 and ATCC 25253, was injected into the water stream of the different irrigation systems to determine survival in the field. Results showed that product samples were positive for E. coli up to 7 days when using sprinkler irrigation, whereas only one product sample was found positive for E. coli when using other irrigation methods. Survival of bacteria in soil persisted longer in furrow-irrigated areas, ranging from an estimated 17 days in winter months to 5 days during the warmer summer periods. This finding combined with results from a parallel 3-year survey of canal waters indicate that while highest risk of finding E. coli in irrigation water is in warmer months, the survival in soil is lower during the same time period. CONCLUSIONS: Our results in a study set under common commercial conditions confirmed the enhanced risk of E. coli contamination when using sprinkle irrigation. Furthermore, E. coli persistence in furrow-irrigated soil validates the importance of an early irrigation termination for both sprinkler and furrow methods.


Assuntos
Irrigação Agrícola , Escherichia coli/fisiologia , Microbiologia de Alimentos , Lactuca/microbiologia , Escherichia coli/isolamento & purificação , Viabilidade Microbiana , Folhas de Planta/microbiologia , Estações do Ano , Microbiologia do Solo , Microbiologia da Água
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