Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
1.
Sci Rep ; 14(1): 25302, 2024 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-39455744

RESUMEN

Laser-driven deuterons generate neutrons with a mean energy of 2.5 MeV, through the 2H(d,n) fusion reaction in a deuterated polyethylene (dPE) tablet. The deuterium ions are accelerated by 12 fs, 21 mJ laser pulses interacting with a 0.2 µm thin dPE foil at a peak intensity of 1018 W/cm2. The laser was operated at 1 Hz repetition rate in bursts of 75 shots. The interaction was characterized and recorded for each laser shot. The ion spectra were measured in the forward and backward directions by Thomson ion spectrometers. Neutron events were detected by a time-of-flight (ToF) system consisting of four plastic scintillators positioned at various angles around the experimental chamber. The maximum cut-off energy of the forward accelerated protons and deuterons was close to 1.4 MeV and 1 MeV, while the mean values are 428 ± 63 keV and 433 ± 80 keV, respectively. Analysis of ToF distributions from 3128 shots resulted in an average yield of 1142 ± 59 neutrons per shot in the energy range of 1.5-4 MeV. The energy distribution of forward-directed neutrons peaks between 3 and 3.5 MeV. Angular dependence analysis showed a perpendicular minimum and a maximum along the deuteron beam, consistent with the expected distribution from the literature and our simulation results.

2.
Rev Sci Instrum ; 92(4): 043701, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-34243430

RESUMEN

The detection of oxygen precipitates, voids, and other defects is critical for semiconductor wafer makers. One of the industry standard techniques for detecting these Bulk Micro-Defects (BMDs) is Semilab's Light Scattering Tomograph (LST) system. In this measurement, unpatterned wafers are nominally cleaved in half. Illumination is applied to the front surface of the sample, and the light scattered off of the defects is collected via the cleaved surface. This technique had been limited to the measurement of unpatterned wafers, but device makers show significant interest in measuring BMD distributions on patterned wafers using scattering-based techniques. A pattern on the surface of the wafer can cause significant scattering, making the standard LST technique unsuitable for this task. We present a solution for patterned wafer BMD measurements by an addition of a low-angle illumination unit to the standard LST system. This new illumination unit focuses the light into the bulk of the wafer via the cleaved surface, which enables measurement on patterned samples. The new system is called "light scattering tomograph enhanced by low-angle illumination." Excellent correlation was found between the detected defect densities obtained by the low-angle and the standard LST illumination mode.

3.
Life Sci ; 268: 118936, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33421523

RESUMEN

AIMS: During oxidative stress mitochondria become the main source of endogenous reactive oxygen species (ROS) production. In the present study, we aimed to clarify the effects of pharmacological PARP-1 inhibition on mitochondrial function and quality control processes. MAIN METHODS: L-2286, a quinazoline-derivative PARP inhibitor, protects against cardiovascular remodeling and heart failure by favorable modulation of signaling routes. We examined the effects of PARP-1 inhibition on mitochondrial quality control processes and function in vivo and in vitro. Spontaneously hypertensive rats (SHRs) were treated with L-2286 or placebo. In the in vitro model, 150 µM H2O2 stress was applied on neonatal rat cardiomyocytes (NRCM). KEY FINDINGS: PARP-inhibition prevented the development of left ventricular hypertrophy in SHRs. The interfibrillar mitochondrial network were less fragmented, the average mitochondrial size was bigger and showed higher cristae density compared to untreated SHRs. Dynamin related protein 1 (Drp1) translocation and therefore the fission of mitochondria was inhibited by L-2286 treatment. Moreover, L-2286 treatment increased the amount of fusion proteins (Opa1, Mfn2), thus preserving structural stability. PARP-inhibition also preserved the mitochondrial genome integrity. In addition, the mitochondrial biogenesis was also enhanced due to L-2286 treatment, leading to an overall increase in the ATP production and improvement in survival of stressed cells. SIGNIFICANCE: Our results suggest that the modulation of mitochondrial dynamics and biogenesis can be a promising therapeutical target in hypertension-induced myocardial remodeling and heart failure.


Asunto(s)
Hipertensión/fisiopatología , Hipertrofia Ventricular Izquierda/tratamiento farmacológico , Mitocondrias Cardíacas/efectos de los fármacos , Miocitos Cardíacos/efectos de los fármacos , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Animales , Células Cultivadas , Citrato (si)-Sintasa/metabolismo , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Electrocardiografía , Glutatión/metabolismo , Hipertrofia Ventricular Izquierda/etiología , Masculino , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Mitocondrias Cardíacas/metabolismo , Mitocondrias Cardíacas/patología , Mitocondrias Cardíacas/ultraestructura , Proteínas Mitocondriales/metabolismo , Miocitos Cardíacos/patología , Péptido Natriurético Encefálico/sangre , Piperidinas/farmacología , Quinazolinas/farmacología , Ratas Endogámicas SHR , Ratas Wistar
4.
Transplant Proc ; 40(4): 1216-7, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18555151

RESUMEN

Although the contraindications for thoracic epidural anesthesia (TEA) are well defined, the debate continues about whether TEA improves outcomes. Pro and con trials and a metaanalysis in the past have yielded equivocal results; they did not deal with new vascular intervention or drugs. The benefit of TEA in surgery is to provide analgesia. In subgroups, TEA can decrease the mortality and morbidity. In contrast, the cost can increase in the situation of a complication that is opposite to the side effects is rare, but the impairment caused by them is out of proportion to the benefits. Primary or secondary prophylaxis with antithrombotic drugs is increasing in developed countries because of the increasing cardiovascular interventions and aging of the population. The neuroaxial guidelines are useful, but the changing of the coagulation profile after hepatectomy is not included in them. The decision to use TEA in liver surgery must be individualized with steps planned from the beginning. TEA suitability is based on an evaluation of the contraindications, comorbidities, coagulation profiles, hepatic reserve, and balance of benefits and risks. The insertion or withdrawal of the epidural catheter should be made with care according to the neuroaxial guidelines and in the presence of a normal TEG. The decreasing level of prothrombin content and platelet counts after hepatectomy should be closely monitored every 2 to 5 days.


Asunto(s)
Anestesia Epidural , Analgesia Epidural , Anestesia Epidural/efectos adversos , Fibrinolíticos/uso terapéutico , Hematoma/etiología , Humanos , Hipotensión/etiología , Náusea/etiología , Periodo Posoperatorio , Traumatismos de la Médula Espinal/etiología , Negativa del Paciente al Tratamiento , Inconsciencia
5.
Transplant Proc ; 38(3): 798-800, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16647474

RESUMEN

New limits have been established to decrease mortality and morbidity rates after liver resection in cirrhotic and non-cirrhotic patients. Various laboratory data and imaging techniques have been used to complement the Child-Pugh score to predict liver failure after hepatectomy and to assess functional hepatic reserve. The greatest experiences are with the aminopyrine breath test and the galactosyl elimination capacity, which are decreased among hepatic failure patients after liver resection. However, absence of these changes do not totally exclude it. The indocyanine green retention test is the most widely used clearance test. Nevertheless, it remains imperfect because it depends both on hepatic blood flow and on the functional capacity of the liver. Nuclear imaging of the asialoglicoprotein receptors with radiolabelled synthetic asialoglicoproteins provides volumetric information as well a functional assessment of the liver. In summary, while liver function is complex, a successful liver test to assess quantitative functional hepatic reserve still needs to be established. The combination of the Child-Pugh score, the presence of ascites, the serum bilirubin levels, the indocyanine green retention (ICG R15) value, and the remnant liver CT volumetry seems to avoid an index of liver failure after hepatic resection. Cases when ICG R15 is above 15% should be combined with portal vein embolization. If there is no possibility to perform an ICG clearance test, it may be replaced with other available, well known dynamic liver function tests.


Asunto(s)
Cirrosis Hepática/cirugía , Hepatopatías/cirugía , Pruebas de Función Hepática , Aminopirina , Antiinflamatorios no Esteroideos , Bilirrubina/sangre , Pruebas Respiratorias , Hepatectomía/mortalidad , Humanos , Ensayos Clínicos Controlados Aleatorios como Asunto
6.
Neuroscience ; 115(3): 961-78, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12435433

RESUMEN

The distribution, morphology, synaptic coverage and postsynaptic targets of calbindin-containing interneurons and afferent pathways have been analyzed in the control and epileptic CA1 region of the human hippocampus. Numerous calbindin-positive interneurons are preserved even in the strongly sclerotic CA1 region. The morphology of individual cells is altered: the cell body and dendrites become spiny, the radially oriented dendrites disappear, and are replaced by a large number of curved, distorted dendrites. Even in the non-sclerotic epileptic samples, where pyramidal cells are present and calbindin-immunoreactive interneurons seem to be unchanged, some modifications could be observed at the electron microscopic level: they received more inhibitory synaptic input, and the calbindin-positive excitatory afferents - presumably derived from the CA1, the CA2 and/or the dentate gyrus - are sprouted. In the strongly sclerotic tissue, with the death of pyramidal cells, calbindin-positive terminals (belonging to interneurons and the remaining excitatory afferents) change their targets. Our data suggest that an intense synaptic reorganization takes place in the epileptic CA1 region, even in the non-sclerotic tissue, before the death of considerable numbers of pyramidal cells. Calbindin-positive interneurons participate in this reorganization: they show plastic changes in response to epilepsy. The enhanced inhibition of inhibitory interneurons may result in the disinhibition of pyramidal cells or in an abnormal synchrony in the output region of the hippocampus.


Asunto(s)
Vías Aferentes/metabolismo , Epilepsia del Lóbulo Temporal/metabolismo , Hipocampo/metabolismo , Interneuronas/metabolismo , Plasticidad Neuronal/fisiología , Proteína G de Unión al Calcio S100/metabolismo , Sinapsis/metabolismo , Adulto , Vías Aferentes/patología , Vías Aferentes/ultraestructura , Calbindinas , Dendritas/metabolismo , Dendritas/patología , Dendritas/ultraestructura , Epilepsia del Lóbulo Temporal/patología , Epilepsia del Lóbulo Temporal/fisiopatología , Femenino , Hipocampo/patología , Hipocampo/ultraestructura , Humanos , Inmunohistoquímica , Interneuronas/patología , Interneuronas/ultraestructura , Masculino , Microscopía Electrónica , Persona de Mediana Edad , Terminales Presinápticos/metabolismo , Terminales Presinápticos/patología , Terminales Presinápticos/ultraestructura , Células Piramidales/metabolismo , Células Piramidales/patología , Células Piramidales/ultraestructura , Sinapsis/patología , Sinapsis/ultraestructura , Membranas Sinápticas/metabolismo , Membranas Sinápticas/patología , Membranas Sinápticas/ultraestructura
7.
Int J Food Microbiol ; 166(1): 176-85, 2013 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-23891865

RESUMEN

Mycotoxins are secondary fungal metabolites that may have mutagenic, carcinogenic, cytotoxic and endocrine disrupting effects. These substances frequently contaminate agricultural commodities despite efforts to prevent them, so successful detoxification tools are needed. The application of microorganisms to biodegrade mycotoxins is a novel strategy that shows potential for application in food and feed processing. In this study we investigated the mycotoxin degradation ability of thirty-two Rhodococcus strains on economically important mycotoxins: aflatoxin B1, zearalenone, fumonisin B1, T2 toxin and ochratoxin A, and monitored the safety of aflatoxin B1 and zearalenone degradation processes and degradation products using previously developed toxicity profiling methods. Moreover, experiments were performed to analyse multi-mycotoxin-degrading ability of the best toxin degrader/detoxifier strains on aflatoxin B1, zearalenone and T2 toxin mixtures. This enabled the safest and the most effective Rhodococcus strains to be selected, even for multi-mycotoxin degradation. We concluded that several Rhodococcus species are effective in the degradation of aromatic mycotoxins and their application in mycotoxin biodetoxification processes is a promising field of biotechnology.


Asunto(s)
Microbiología de Alimentos , Micotoxinas/metabolismo , Rhodococcus/metabolismo , Inactivación Metabólica , Micotoxinas/química , Especificidad de la Especie
8.
Acta Physiol Hung ; 99(2): 99-110, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22849833

RESUMEN

Foregoing researches made on the N/OFQ system brought up a possible role for this system in cardiovascular regulation. In this study we examined how N/OFQ levels of the blood plasma changed in acute cardiovascular diseases. Three cardiac patient groups were created: enzyme positive acute coronary syndrome (EPACS, n = 10), enzyme negative ACS (ENACS, n = 7) and ischemic heart disease (IHD, n = 11). We compared the patients to healthy control subjects (n = 31). We found significantly lower N/OFQ levels in the EPACS [6.86 (6.21-7.38) pg/ml], ENACS [6.97 (6.87-7.01) pg/ml and IHD groups [7.58 (7.23-8.20) pg/ml] compared to the control group [8.86 (7.27-9.83) pg/ml]. A significant correlation was detected between N/OFQ and white blood cell count (WBC), platelet count (PLT), creatine kinase (CK), glutamate oxaloacetate transaminase (GOT) and cholesterol levels in the EPACS group.Decreased plasma N/OFQ is closely associated with the presence of acute cardiovascular disease, and the severity of symptoms has a significant negative correlation with the N/OFQ levels. We believe that the rate of N/OFQ depression is in association with the level of ischemic stress and the following inflammatory response. Further investigations are needed to clarify the relevance and elucidate the exact effects of the ischemic stress on the N/OFQ system.


Asunto(s)
Síndrome Coronario Agudo/sangre , Péptidos Opioides/sangre , Síndrome Coronario Agudo/diagnóstico , Anciano , Aspartato Aminotransferasas/sangre , Biomarcadores/sangre , Colesterol/sangre , Creatina Quinasa/sangre , Regulación hacia Abajo , Femenino , Humanos , Hungría , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Recuento de Plaquetas , Índice de Severidad de la Enfermedad , Nociceptina
9.
Acta Physiol Hung ; 96(4): 475-82, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19942554

RESUMEN

Fatness generally has a negative influence on the performance of a variety of motor and cardiorespiratory fitness tests. The aim of this comparison was to analyse the effects of three grades of obesity on somatic growth, physical performance and oxygen consumption during exercise. Volunteer boys with definitely different grades of obesity were recruited for the comparison. In the group of mildly obese children (G1; n=23) BMI ranged between 24 kg.m -2 and 26 kg.m -2 ; and individual percent body fat was between 33% and 33.5%. In the case of moderate obesity (G2; n=23) BMI ranged between 26.5 kg.m -2 and 28.5 kg.m -2 ; and percent body fat was between 35% and 36%. In the extremely obese group (G3; n=20) BMI was greater than 31 kg.m -2 ; percent body fat was greater than 37.5%. Oxygen consumption during the 1,200 m run-test was measured by VIMEX-ST-type (USA) telemetric equipment.The greatest absolute aerobic power referred to the G3 boys, and the lowest oxygen consumption was characteristic of the mildly obese group. The very high differences between the body mass means resulted in a more marked inter-group variability in mean relative oxygen uptake.The predicted relative fat and high body fat content observed on the trunk, and the elevated level of resting blood pressure may indicate serious risks for the development of cardio-respiratory and metabolic disease. The very low oxygen consumption relative to body mass and poor physical performance are expected consequences of physiologic and environmental influences on the obese population.


Asunto(s)
Obesidad/fisiopatología , Consumo de Oxígeno , Aptitud Física , Adiposidad , Presión Sanguínea , Índice de Masa Corporal , Niño , Prueba de Esfuerzo , Humanos , Masculino , Mecánica Respiratoria , Índice de Severidad de la Enfermedad
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA