RESUMEN
BACKGROUND: It is unclear whether and under which conditions stretch training programs lead to gains in flexibility when applied in work health promotion for office workers in order to reduce musculoskeletal disorders (MSD). OBJECTIVE: The aim of this study was to analyze whether the stretch training "five-Business" leads to gains in range of motion (ROM). Furthermore, the influence of baseline flexibility and socio-demographic factors (sex, age, weight, height and body mass index (BMI)) on trainability was assessed. METHODS: 161 office workers (nâ=â45 female; nâ=â116 male) without major MSD were recruited. Over three months, a standardized static stretch training ("five-Business") was executed on a device, supervised twice per week for 10âmin. ROM was assessed using a digital inclinometer (shoulder, hip and trunk extension) and a tape measure (fingertip-to-floor and lateral inclination). RESULTS: ROM gains (p≤0.001) were present in all tests, except for the hip extension. ROM changes correlated moderately (0.24-0.62) with the baseline flexibility (p≤0.001). Subjects with limited flexibility reached the largest gains (1.41-25.33%). Regarding the socio-demographic factors only one low correlation occurred (weight - retroflexion; -0.177). CONCLUSION: The "five-Business" stretch training effectively increases ROM in office workers, especially when baseline flexibility is limited.
Asunto(s)
Enfermedades Musculoesqueléticas , Hombro , Femenino , Humanos , Masculino , Rango del Movimiento Articular , TorsoRESUMEN
Automated seizure detection ushers the prospect for issuance of warning, but to benefit from it, patients must be responsive when warnings are issued. By use of a complex reaction time test triggered by a seizure detection algorithm, the latency to impairment of responsiveness was measured during seizure versus interictal conditions in 14 patients undergoing surgical evaluation with intracranial electrodes. Mean latency to impairment of responsiveness from electrographic onset was 27.1, 42.8, or 56.1 seconds depending on the stringency of the defining criterion. Mean, SD, and distributions of compliance and percentage of correct responses did not significantly differ between seizure and interictal tests. If reproduced in studies performed under more realistic conditions, the latency to impairment of responsiveness justifies the development of a warning device to allow patients to perform activities precluded by seizures and decrease the risk of injury. If endowed with automated therapy delivery, said device would advance epilepsy management cost-effectively.
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Encéfalo/fisiopatología , Procesamiento Automatizado de Datos/métodos , Epilepsias Parciales/diagnóstico , Tiempo de Reacción/fisiología , Adolescente , Adulto , Algoritmos , Niño , Preescolar , Electroencefalografía/métodos , Epilepsias Parciales/fisiopatología , Epilepsias Parciales/cirugía , Estudios de Factibilidad , Femenino , Lateralidad Funcional , Humanos , Masculino , Estadísticas no Paramétricas , Adulto JovenRESUMEN
Substantive advances in clinical epileptology may be realized through the judicious use of real-time automated seizure detection, quantification, warning, and delivery of therapy in subjects with pharmacoresistant seizures. Materialization of these objectives is likely to elevate epileptology to the level of a mature clinical science.
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Epilepsia/diagnóstico , Epilepsia/fisiopatología , Reconocimiento de Normas Patrones Automatizadas/métodos , Procesamiento de Señales Asistido por Computador , Algoritmos , Electroencefalografía , Epilepsia/terapia , Humanos , Dinámicas no Lineales , Factores de TiempoRESUMEN
Topological approaches for seizure abatement have received scarce attention. The ability to reset the phase of biological oscillations has been widely exploited in cardiology, as evidenced in part by the usefulness of implantable of defibrillators, but not in epileptology. The aim of this work is to investigate the feasibility of seizure blockage using single or brief monophasic (DC) pulse trains. Single DC or brief (0.1 s) pulse trains were delivered manually or automatically to generalized seizures, induced in rats with the convulsant 3-mercaptoprionic acid, a GABA inhibitor. Treatment outcome (blocked vs. not blocked seizures) was ascertained visually and correlated with the "rhythmicity index", an indirect estimate of neuronal synchrony level. Blockage using single or brief (0.1 s) DC pulses was consistently achieved for seizures with a rhythmicity index > 0.6, while seizures with levels <0.6 were not, although transient phase changes in their oscillations were effected. This work reveals that level of neuronal synchronization may be an important factor in determining the probability of seizure blockage. Seizure blockage using single or brief DC pulse trains and its effects on neural tissue merit further investigation. The clinical applicability of this therapeutic modality and means to enhance it are discussed.
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Relojes Biológicos/fisiología , Encéfalo/fisiopatología , Terapia por Estimulación Eléctrica/métodos , Epilepsia/fisiopatología , Epilepsia/terapia , Potenciales Evocados/fisiología , Ácido 3-Mercaptopropiónico/farmacología , Potenciales de Acción/fisiología , Animales , Convulsivantes/farmacología , Modelos Animales de Enfermedad , Terapia por Estimulación Eléctrica/instrumentación , Electricidad , Electrodos Implantados , Electrónica Médica/instrumentación , Electrónica Médica/métodos , Epilepsia/inducido químicamente , Masculino , Neuronas/fisiología , Periodicidad , Ratas , Ratas Wistar , Resultado del TratamientoRESUMEN
We describe a case of aseptic meningitis due to Toscana Virus imported to Switzerland and discuss the epidemiological situation. To our knowledge this is the first description of this infection acquired on the Island of Elba.
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Brotes de Enfermedades/estadística & datos numéricos , Meningitis Aséptica/diagnóstico , Meningitis Aséptica/epidemiología , Fiebre por Flebótomos/diagnóstico , Fiebre por Flebótomos/epidemiología , Virus de Nápoles de la Fiebre de la Mosca de los Arenales , Viaje , Geografía , Humanos , Italia/epidemiología , Masculino , Vigilancia de la Población , Medición de Riesgo/métodos , Factores de Riesgo , Suiza/epidemiología , Adulto JovenRESUMEN
A new entity was described by Crickx et al. in 1991, associating amicrobial pustulosis of the folds with systemic lupus erythematosus in young females. It is proposed to regroup this entity under the name of 'neutrophilic cutaneous lupus'. We report a case of a 13-year-old girl with a pustular eruption of the cutaneous folds and scalp associated with undetermined connective tissue disease. We performed a screening for the expression of 174 cytokines in the pustules and compared it with other pustular diseases (acne flare, acute generalized exanthematous pustulosis, pustulosis of Sneddon and Wilkinson). Matrix metalloproteinase 9 and Siglec-5 (CD170) were highly expressed in all types of pustules and reflect high neutrophil density. Amicrobial pustulosis of the folds was characterized by a higher expression of interleukin (IL) 1alpha, IL-2 receptor alpha, macrophage colony-stimulating factor, insulin-like growth factor binding protein 1, brain-derived neurotrophic factor, tumour necrosis factor (TNF) alpha and a lower expression of CD14, IL-1beta, IL-12, soluble TNF receptors I and II, growth-regulated oncogene alpha, fibroblast growth factor 4 and vascular endothelial growth factor as compared to the controls.
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Citocinas/metabolismo , Lupus Eritematoso Cutáneo/patología , Enfermedades de la Piel/patología , Adolescente , Anciano de 80 o más Años , Femenino , Humanos , Inmunoglobulinas/inmunología , Inmunoglobulinas/metabolismo , Lupus Eritematoso Cutáneo/clasificación , Lupus Eritematoso Cutáneo/inmunología , Masculino , Metaloproteinasa 9 de la Matriz/metabolismo , Proteínas de la Membrana/inmunología , Proteínas de la Membrana/metabolismo , Persona de Mediana Edad , Neutrófilos/clasificación , Neutrófilos/inmunología , Neutrófilos/patología , Enfermedades de la Piel/clasificación , Enfermedades de la Piel/inmunología , Enfermedades de la Piel/metabolismo , SíndromeRESUMEN
The behaviour of dry powder blends for inhalation, depending on the amount of fine lactose particles smaller than 10microm and the presence of magnesium stearate (MgSt), was studied in this work. A laser light diffraction method was developed to determine accurately size and volume fraction of these fine lactose particles in coarse carrier lactose (x(50) approximately 220microm). A linear relationship between measured volume fraction undersize at 10microm Q(3)(10microm) and added fine lactose could be established. Aerodynamic particle size distribution analysis of lactose showed that the fine lactose was attached to the coarse particles. In the presence of MgSt this interaction was increased. Consequently, the number of free active sites on the carrier surface was reduced and the investigated drug (formoterol fumarate dihydrate) was more effectively delivered. Addition of fine lactose and MgSt improved the aerodynamic performance the drug, as determined by resulting fine particle fraction, by 3% (for each 1% of added fine lactose) and 10%, respectively. Stability tests indicated that added MgSt was the most relevant of the studied parameter to achieve a stable aerodynamic performance. Its ability to protect the moisture uptake into the system was considered as rational for this effect.
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Lactosa/química , Tamaño de la Partícula , Polvos/química , Ácidos Esteáricos/química , Administración por Inhalación , Algoritmos , Broncodilatadores/administración & dosificación , Broncodilatadores/química , Estabilidad de Medicamentos , Etanolaminas/administración & dosificación , Etanolaminas/química , Excipientes/química , Fumarato de Formoterol , Luz , Mecánica , Vehículos Farmacéuticos/química , Dispersión de Radiación , SonicaciónRESUMEN
BACKGROUND: The aim of this study is to evaluate the safety and sufficiency of a fixed dose rate propofol infusion for repeated prolonged deep sedation in children for proton radiation therapy (PRT). METHODS: With ERB approval, we recorded anaesthesia monitoring data in children undergoing repeated prolonged propofol sedation for PRT. Sedation was introduced with a single bolus of i.v. midazolam 0.1 mg kg(-1) followed by repeated small boluses of propofol until sufficient depth of sedation was obtained. Sedation was maintained with fixed dose rate propofol infusion of 10 mg kg(-1) h(-1) in all patients up to the end of the radiation procedure. Patient characteristics, number and duration of sedation, propofol induction dose, necessity to alter propofol infusion rate, and heart rate, mean arterial pressure, respiratory rate were noted at the end of the radiation procedure before cessation of the propofol infusion. Data are mean (sd) or range (median) as appropriate. RESULTS: Eighteen children aged from 1.4 to 4.2 yr (2.6 yr) had 27.6 (sd 2.0) (497 in total) radiation procedures within 44.1 (4.0) days lasting 55.7 (8.8) min. Propofol bolus dose for induction, monitoring, and positioning was 3.7 (1.0) mg kg(-1). Propofol bolus requirements were quite stable over the successive weeks of treatment and variability was larger between individuals than over time. In none of the children did propofol infusion rate need to be changed from the pre-set 10 mg kg(-1) h(-1) flow rate because of haemodynamic state, respiratory conditions or inadequate anaesthesia. CONCLUSIONS: Repeated prolonged deep sedation over several weeks in very young children using a fixed rate propofol infusion was safe and adequate for all patients.
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Sedación Consciente/métodos , Hipnóticos y Sedantes , Propofol , Terapia de Protones , Radioterapia Conformacional/métodos , Presión Sanguínea/efectos de los fármacos , Preescolar , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Hipnóticos y Sedantes/administración & dosificación , Lactante , Infusiones Intravenosas , Masculino , Propofol/administración & dosificación , Mecánica Respiratoria/efectos de los fármacosRESUMEN
BACKGROUND AND OBJECTIVE: To compare the recently introduced Microcuff endotracheal tube with conventional tubes in respect of the cuff pressures required to prevent air leakage. METHODS: The following tubes (ID 7.0mm) were compared: Microcuff HVLP ICU, Mallinckrodt HiLo, Portex Profile Soft Seal, Rüsch Super Safety Clear and Sheridan CF. Fifty patients undergoing endotracheal intubation with a cuffed tube of internal diameter 7.0 mm were studied. Tracheas were intubated using one of the endotracheal tubes in random order. Cuff pressure to prevent air leakage at standardized ventilator setting (peak inspiratory pressure 20 cmH2O/PEEP 5 cmH2O/respiratory rate 15 breaths min(-1)) was assessed by auscultation of audible sounds at the mouth. Patients characteristics and cuff pressures from each brand were compared to the Microcuff group using the Mann-Whitney U-test (P < 0.05 was chosen as the level of statistical significance). RESULTS: Patients' median age (range) was 14.2 (12.0-17.1) yr, body weight 57.5 (40.0-81.9) kg and length 164.9 (146.5-190.0) cm. No significant differences in patients' characteristics were found between groups. Mean cuff pressure (all tubes) required for air sealing was 19.1 (8-42) cmH2O. The Microcuff tube required significantly lower sealing pressures (9.5 (8-12) cmH2O) compared to the other brands of endotracheal tube (P < 0.05, Mann-Whitney U-test). CONCLUSION: The Microcuff endotracheal tube with its ultra-thin polyurethane cuff membrane required the lowest sealing pressure to prevent air leakage. These features are potentially of interest for long-term intubated patients and for cuffed endotracheal tubes in children, allowing tracheal sealing at lower cuff pressures implying less damage to the trachea.
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Anestesia , Intubación Intratraqueal/instrumentación , Adolescente , Anestésicos por Inhalación , Niño , Humanos , Éteres Metílicos , Poliuretanos , Presión , Ruidos Respiratorios , SevofluranoRESUMEN
Previous studies of the effects of electrical vagus stimulation on experimental seizures were without suitable controls or statistical validation, and ignored the potential role of vagally-induced hemodynamic depression on seizure expression. This study addresses these limitations. The effects of periodic left vagus nerve stimulation (LVNS) on chemically-induced seizures in rats were compared with control groups receiving no stimulation (NoS), left sciatic nerve stimulation (LSNS) and LVNS after pretreatment with methyl atropine (MA-LVNS). Stimulation followed a 30 s on-120 s off cycle over 130 min. Seizures were scored visually and the temporal variation of their probability P(s) across the stimulation cycle was measured statistically. P(s) was significantly different (P<0.01) for all groups: LSNS had the highest and MA-LVNS the lowest seizure probability; LVNS and NoS had intermediate values. While LVNS blocked seizures, it also precipitated them, explaining why its anti-seizure effect was only slightly greater than NoS. Neither LVNS nor MA-LVNS induced changes in cortical rhythms ('activation') associated with decreased P(s), unlike LSNS which increased cortical rhythm synchrony and with it, P(s). LVNS alone induced marked bradycardia and moderate hypoxemia. In conclusion, cranial and peripheral nerve stimulation have complex, time-varying effects on cerebral excitability: low frequency LSNS facilitated seizures, while LVNS both suppressed and facilitated them. The anti-seizure effect of LVNS was small and may have, in part, been due to a hemodynamically-induced deficit in energy substrates. The effects of MA-LVNS on seizure duration and P(s) raise the possibility that, in the absence of hemodynamic depression, stimulation of this nerve does not have a strong anti-seizure effect.
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Corteza Cerebral/fisiopatología , Circulación Cerebrovascular/fisiología , Terapia por Estimulación Eléctrica , Conducción Nerviosa/fisiología , Nervio Ciático/fisiología , Convulsiones/terapia , Nervio Vago/fisiología , Animales , Derivados de Atropina/farmacología , Bradicardia/etiología , Bradicardia/fisiopatología , Corteza Cerebral/efectos de los fármacos , Circulación Cerebrovascular/efectos de los fármacos , Sincronización Cortical/efectos de los fármacos , Sincronización Cortical/métodos , Masculino , Modelos Neurológicos , Trastornos del Movimiento/etiología , Trastornos del Movimiento/fisiopatología , Parasimpatolíticos/farmacología , Ratas , Ratas Sprague-Dawley , Tiempo de Reacción/efectos de los fármacos , Tiempo de Reacción/fisiología , Fenómenos Fisiológicos Respiratorios/efectos de los fármacos , Convulsiones/inducido químicamente , Convulsiones/fisiopatología , Factores de Tiempo , Nervio Vago/efectos de los fármacosRESUMEN
PURPOSE: The purpose of this study was to determine if stimulation of the left vagus nerve (LVNS) with the neurocybernetic prosthesis (NCP) in humans is, as claimed in the literature, without cardiac chronotropic actions. METHODS: We analyzed 228 h of ECG recorded from five subjects with intractable epilepsy who had not benefited from LVNS, for effects on instantaneous heart rate (IHR) and heart rate variability (HRV). RESULTS: There were two main cardiac responses: (a) bradycardia, and (b) tachycardia during the first half, followed by bradycardia during the second half of stimulation (biphasic response). Multiphasic responses characterized by alternating bradycardia and tachycardia were rarely observed. HRV was either increased or decreased depending on the subject and on the stimulation parameters. HRV as a function of HR also showed high interindividual variability, and interestingly, in one case behaved paradoxically, increasing at higher and decreasing at lower heart rates. CONCLUSIONS: LVNS at high intensities has complex effects on IHR and HRV, which show large interindividual variability. These spectra of cardiac responses reflect the interplay of autonomic, visceral, and somatic sensory afferences and the role of central structures in their integration. These findings also point to the need for more comprehensive studies of cardiac function in humans implanted with the NCP, using sensitive methods for data processing and analysis such as those developed for this study.
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Terapia por Estimulación Eléctrica/métodos , Electrocardiografía/estadística & datos numéricos , Epilepsia/terapia , Frecuencia Cardíaca/fisiología , Nervio Vago/fisiología , Adulto , Cibernética/métodos , Femenino , Corazón/inervación , Corazón/fisiología , Humanos , Masculino , Monitoreo Fisiológico/estadística & datos numéricos , Cuidados Preoperatorios , Prótesis e ImplantesRESUMEN
The authors reexamine the correlation integral and the related correlation dimension in the context of EEG analysis with application to seizure prediction. They identify dependencies of the correlation integral and the correlation dimension on frequency and amplitude of the signal, which may result in a reinterpretation of the dynamic importance of these measures and may cast doubts on their predictive abilities for certain classes of seizures. The relevance, for clinical and research purposes, of the distinction between retrospective and prospective inference (prediction) is addressed briefly. The authors point to the need for further research, consisting of long time series, containing multiple seizures, and for the development of objective prediction criteria.
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Electroencefalografía/estadística & datos numéricos , Epilepsia/diagnóstico , Corteza Cerebral/fisiopatología , Epilepsia/fisiopatología , Potenciales Evocados/fisiología , Análisis de Fourier , Humanos , Modelos Estadísticos , Procesamiento de Señales Asistido por ComputadorRESUMEN
It has been suggested that chronic, low-level exposure to radiofrequency (RF) radiation may promote the formation of tumors. Previous studies, however, showed that low-level, long-term exposure of mammary tumor-prone mice to 435 MHz or 2450 MHz RF radiation did not affect the incidence of mammary tumors. In this study, we investigated the effects of exposure to a unique type of electromagnetic energy: pulses composed of an ultra-wideband (UWB) of frequencies, including those in the RF range. One hundred C3H/HeJ mice were exposed to UWB pulses (rise time 176 ps, fall time 3.5 ns, pulse width 1.9 ns, peak E-field 40 kV/m, repetition rate 1 kHz). Each animal was exposed for 2 min once a week for 12 weeks. One hundred mice were used as sham controls. There were no significant differences between groups with respect to incidence of palpated mammary tumors, latency to tumor onset, rate of tumor growth, or animal survival. Histopathological evaluations revealed no significant differences between the two groups in numbers of neoplasms in all tissues studied (lymphoreticular tissue, thymus, respiratory, digestive and urinary tracts, reproductive, mammary and endocrine systems, and skin). Our major finding was the lack of effects of UWB-pulse exposure on promotion of mammary tumors in a well-established animal model of mammary cancer.
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Campos Electromagnéticos/efectos adversos , Neoplasias Mamarias Experimentales/etiología , Neoplasias Inducidas por Radiación/etiología , Animales , Peso Corporal , Relación Dosis-Respuesta en la Radiación , Exposición a Riesgos Ambientales , Femenino , Predisposición Genética a la Enfermedad , Ratones , Ratones Endogámicos C3H , Microondas/efectos adversos , Metástasis de la Neoplasia , Neoplasias Experimentales/etiología , Neoplasias Experimentales/genética , Especificidad de Órganos , Ondas de Radio/efectos adversosRESUMEN
Automated seizure blockage is a top research priority of the American Epilepsy Society. This delivery modality (referred to herein as contingent or closed loop) requires for implementation a seizure detection algorithm for control of delivery of therapy via a suitable device. The authors address the many potential advantages of this modality over conventional alternatives (periodic or continuous), and the challenges it poses in the design and analysis of trials to assess efficacy and safety-in the particular context of direct delivery of electrical stimulation to brain tissue. The experimental designs of closed-loop therapies are currently limited by ethical, technical, medical, and practical considerations. One type of design that has been used successfully in an in-hospital "closed-loop" trial using subjects undergoing epilepsy surgery evaluation as their own controls is discussed in detail. This design performs a two-way comparison of seizure intensity, duration, and extent of spread between the control (surgery evaluation) versus the experimental phase, and, within the experimental phase, between treated versus untreated seizures. The proposed statistical analysis is based on a linear model that accounts for possible circadian effects, changes in treatment protocols, and other important factors such as change in seizure probability. The analysis is illustrated using seizure intensity as one of several possible end points from one of the subjects who participated in this trial. In-hospital ultra-short-term trials to assess safety and efficacy of closed-loop delivery of electrical stimulation for seizure blockage are both feasible and valuable.
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Terapia por Estimulación Eléctrica , Electroencefalografía , Epilepsia/terapia , Anticonvulsivantes/administración & dosificación , Anticonvulsivantes/efectos adversos , Ensayos Clínicos como Asunto , Electrodos Implantados , Epilepsia/fisiopatología , Potenciales Evocados/fisiología , Humanos , Procesamiento de Señales Asistido por Computador , Resultado del TratamientoRESUMEN
The authors describe an integrated bedside system for real-time seizure detection and automated delivery of electrical stimulation directly to the brain of subjects undergoing invasive epilepsy surgery evaluation. These stimulations were triggered by specific detections following a prespecified pattern. The system uses a commercially available EEG unit, two personal computers, two Grass S-12 stimulators, and other custom-built units to enable interfacing between these components. To date, more than 9,500 hours of electrocorticographic data have been acquired, displayed, and analyzed, and more than 900 closed-loop stimulations for seizure blockage have been delivered safely and reliably to eight subjects with intractable epilepsy. This system generates on-line reports containing information about seizures that provide the epileptologist with timely, valuable data while allowing adaptation of the algorithm detection parameters to improve its performance if necessary. Additionally, it can control the output of any therapeutic device and administrate automatically cognitive tests or radioactive tracers for neuroimaging purposes. This network system, which can be replicated at a relatively low cost by others, is proof of concept for a portable or implantable device that could serve identical functions. Widespread availability of this type of system will advance the fields of clinical and basic epilepsy rapidly and considerably.
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Terapia por Estimulación Eléctrica/instrumentación , Electroencefalografía/instrumentación , Epilepsia/terapia , Sistemas de Atención de Punto , Procesamiento de Señales Asistido por Computador/instrumentación , Corteza Cerebral/fisiopatología , Sistemas de Computación , Electrodos Implantados , Epilepsia/fisiopatología , Humanos , Microcomputadores , Interfaz Usuario-ComputadorRESUMEN
Relatively large thermal gradients may exist during exposure of an animal to microwaves (MWs), particularly at high frequencies. Differences in thermal gradients within the body may lead to noticeable differences in the magnitude of cardiovascular changes resulting from MW exposure. This study compares the thermal distribution and cardiovascular effects of exposure to a single MW frequency with effects of simultaneous exposure to two frequencies. Ketamine-anesthetized male Sprague-Dawley rats (n = 58) were exposed individually to one of three conditions: 1-GHz, 10-GHz, or combined 1- and 10-GHz MWs at an equivalent whole-body specific absorption rate of 12 W/kg. The continuous-wave irradiation was conducted under far-field conditions with animals in E orientation (left lateral exposure, long axis parallel to the electric field) or in H orientation (left lateral exposure, long axis perpendicular to the electric field). Irradiation was started when colonic temperature was 37.5 degrees C and was continued until lethal temperatures were attained. Colonic, tympanic, left and right subcutaneous, and tail temperatures, and arterial blood pressure, heart rate, and respiratory rate were continuously recorded. In both E and H orientations, survival time (i.e., time from colonic temperature of 37.5 degrees C until death) was lowest in animals exposed at 1-GHz, intermediate in those exposed at 1- and 10-GHz combined, and greatest in the 10-GHz group (most differences statistically significant). At all sites (with the exception of right subcutaneous), temperature values in the 1- and 10-GHz combined group were between those of the single-frequency exposure groups in both E and H orientations. During irradiation, arterial blood pressure initially increased and then decreased until death. Heart rate increased throughout the exposure period. The general, overall patterns of these changes were similar in all groups. The results indicate that no unusual physiological responses occur during multi-frequency MW exposure, when compared with results of single-frequency exposure. Bioelectromagnetics 21:159-166, 2000. Published 2000 Wiley-Liss, Inc.
Asunto(s)
Temperatura Corporal/efectos de la radiación , Corazón/efectos de la radiación , Microondas/clasificación , Análisis de Varianza , Anestesia General , Anestésicos Disociativos/administración & dosificación , Animales , Presión Sanguínea/efectos de la radiación , Colon/fisiología , Colon/efectos de la radiación , Umbral Diferencial , Oído Medio/fisiología , Oído Medio/efectos de la radiación , Exposición a Riesgos Ambientales , Frecuencia Cardíaca/efectos de la radiación , Ketamina/administración & dosificación , Masculino , Postura , Dosis de Radiación , Ratas , Ratas Sprague-Dawley , Respiración/efectos de la radiación , Temperatura Cutánea/efectos de la radiación , Tasa de Supervivencia , Cola (estructura animal)/fisiología , Cola (estructura animal)/efectos de la radiación , Factores de Tiempo , Irradiación Corporal TotalRESUMEN
A family of finite impulse-response (FIR) filters is derived which estimate the second derivative or "acceleration" of a digitized signal. The acceleration is obtained from parabolas that are continuously fit to the signal using a least squares optimization criterion. A closed-form solution for the filter coefficients is obtained. The general approach is computationally simple, can be performed in real-time, and is robust in the presence of noise. An important application of the method, that of measuring sharpness in biologic signals, is presented using the electroencephalogram (EEG) and electrocardiogram (EKG) signals as examples. Furthermore, the design method is extended to derive FIR filters for estimating derivatives of arbitrary order in digital signals of biologic or other origins.
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Electrocardiografía , Electroencefalografía , Análisis de los Mínimos Cuadrados , Procesamiento de Señales Asistido por Computador , Algoritmos , Artefactos , Epilepsia/diagnóstico , HumanosRESUMEN
We investigated the thermal distribution and cardiovascular effects produced by sustained exposure of rats to 94 GHz radio-frequency electromagnetic radiation (RFR). Sixteen ketamine-anesthetized Sprague-Dawley rats were exposed individually at a power density of 75 mW/cm2 under far-field conditions in E orientation. Irradiation began when colonic temperature was 37 degrees C and continued until death. Large, immediate increases in subcutaneous temperature on the irradiated side were accompanied by more moderate, delayed increases in colonic temperature. These body-temperature responses were similar to previous results obtained during 35 GHz RFR exposure. During irradiation, arterial blood pressure initially increased and then precipitously decreased until death. The heart rate increased throughout the exposure period. When comparing the results of these 94 GHz exposures with those in previous studies of lower RFR frequencies, it appears that the patterns of heart-rate and blood-pressure changes that occur before death are similar. We conclude that exposure to 94 GHz RFR produces extreme peripheral heating without similar levels of core heating and that this pattern of heat deposition is sufficient to produce circulatory failure and subsequent death.