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The Femtosecond X-ray Experiments (FXE) instrument at the European X-ray Free-Electron Laser (EuXFEL) provides an optimized platform for investigations of ultrafast physical, chemical and biological processes. It operates in the energy range 4.7-20â keV accommodating flexible and versatile environments for a wide range of samples using diverse ultrafast X-ray spectroscopic, scattering and diffraction techniques. FXE is particularly suitable for experiments taking advantage of the sub-MHz repetition rates provided by the EuXFEL. In this paper a dedicated setup for studies on ultrafast biological and chemical dynamics in solution phase at sub-MHz rates at FXE is presented. Particular emphasis on the different liquid jet sample delivery options and their performance is given. Our portfolio of high-speed jets compatible with sub-MHz experiments includes cylindrical jets, gas dynamic virtual nozzles and flat jets. The capability to perform multi-color X-ray emission spectroscopy (XES) experiments is illustrated by a set of measurements using the dispersive X-ray spectrometer in von Hamos geometry. Static XES data collected using a multi-crystal scanning Johann-type spectrometer are also presented. A few examples of experimental results on ultrafast time-resolved X-ray emission spectroscopy and wide-angle X-ray scattering at sub-MHz pulse repetition rates are given.
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Laboratory studies have shown that small concentrations of silver are effective at inhibiting the growth micro-organisms through the disruption of important cell structures and processes. The additional ability to incorporate silver into surfaces has increased the usage of silver in the medical field and expanded its use into the consumer market. To understand the impact of increased silver-containing antimicrobial use, it is important to determine whether silver-based consumer goods are effective at reducing bacterial populations. Our study examined the antibacterial effectiveness of Agion silver zeolite technology applied to 25 silver- and control-coated door handles across a college campus. Door handles were sampled for 6 week periods in both the fall and spring semester, and bacteria were cultured and enumerated on tryptic soy agar (TSA), MacConkey agar (MAC) and mannitol salt agar (MSA). A significant difference was observed between the bacterial populations isolated from silver- and control-coated door handles after 3 years. However, bacteria were consistently isolated from silver-coated door handles suggesting that the silver zeolite was only effective against a portion of the bacterial populations, and further studies are necessary to determine the identities of the isolated bacteria and the prevalence of silver resistance.
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Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Desinfectantes/farmacología , Contaminación de Equipos , Artículos Domésticos , Compuestos de Plata/farmacología , Universidades , Carga Bacteriana , Factores de Tiempo , ZeolitasRESUMEN
Real-Time Location Systems (RTLSs) are promising precision livestock farming tools and have been employed in behavioural studies across various farm animal species. However, their application in research with fattening pigs is so far unexplored. The implementation of these systems has great potential to gain insight into pigs' spatial behaviour such as the use of functional areas and pigs' proximity to each other as indicators for social relationships. The aim of this study was therefore to validate the accuracy, precision, and data quality of the commercial Noldus Information Technology BV TrackLab system. We conducted different measurement sets: first, we performed static measurements in 12 pens at four different locations in each pen at three heights each using a single ultra-wideband tag (UWB). We recorded unfiltered x- and y-coordinates at 1 Hz. We repeated these measurements with six tags aligned in a 2 × 3 grid with varied spacing to test interference between the tags. We also tested dynamic performance by moving the tags along the centre line of the pens. Finally, we measured the data quality with 55 growing pigs in six pens, including the identification of location 'jumps' from the inside to the outside of the pen. Each pen housed ten animals fitted with a UWB tag attached to their farm ear tag. We collected data for 10 days and analysed seven 24-h periods of raw and filtered data. The mean accuracy of the RTLS measurements was 0.53 m (precision: 0.14 m) for single and 0.46 m (precision: 0.07 m) for grouped tags. Accuracy improved with increasing measurement height for single tags but less clearly for grouped tags (P [height single] = 0.01; P [height grouped] = 0.22). When tags were fitted to animals, 63.3% of the filtered data was lost and 21.8% of the filtered location estimates were outside the pens. Altogether, the TrackLab system was capable of fairly accurate and precise assignment of the functional areas where individual animals were located, but was insufficient for the analysis of social relationships. Furthermore, the frequent occurrence of gaps in signal transmission and the overall high data loss rates presented significant limitations. Additionally, the challenging hardware requirements for attaching sensors to the animals underline the need for further technological advances in RTLS for the application with growing-finishing pigs.
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Crianza de Animales Domésticos , Animales , Crianza de Animales Domésticos/métodos , Porcinos , Sistemas de Identificación Animal/veterinaria , Sistemas de Identificación Animal/métodos , Sistemas de Identificación Animal/instrumentación , Conducta Animal , Vivienda para Animales , Sistemas de Información GeográficaRESUMEN
The purpose of this study was to examine the mechanism by which social support influences mental wellbeing. Using the thriving through relationships model to provide a theoretical underpinning, cognitive flexibility was hypothesised as a mediator. Additionally, the research examined the consistency of this pathway between elite athletes, retired athletes, and non-athletes. Survey responses from a sample of 247 participants (n = 49 elite athletes, n = 61 retired athletes, n = 137 convenience sample; of which 127 (51.4%) were males were included in the analysis. Initial mediation analysis revealed a significant indirect pathway from social support to mental wellbeing through cognitive flexibility. Moderated mediation analysis revealed this pathway was significant for retired athletes and the convenience sample, but not for elite athletes. Results provide additional insight into the mechanisms by which social support influences wellbeing. Cognitive flexibility interventions may not be as effective for elite athletes.
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Análisis de Mediación , Deportes , Masculino , Humanos , Femenino , Apoyo Social , Atletas/psicología , CogniciónRESUMEN
High error rates of viral RNA-dependent RNA polymerases lead to diverse intra-host viral populations during infection. Errors made during replication that are not strongly deleterious to the virus can lead to the generation of minority variants. However, accurate detection of minority variants in viral sequence data is complicated by errors introduced during sample preparation and data analysis. We used synthetic RNA controls and simulated data to test seven variant-calling tools across a range of allele frequencies and simulated coverages. We show that choice of variant caller and use of replicate sequencing have the most significant impact on single-nucleotide variant (SNV) discovery and demonstrate how both allele frequency and coverage thresholds impact both false discovery and false-negative rates. When replicates are not available, using a combination of multiple callers with more stringent cutoffs is recommended. We use these parameters to find minority variants in sequencing data from SARS-CoV-2 clinical specimens and provide guidance for studies of intra-host viral diversity using either single replicate data or data from technical replicates. Our study provides a framework for rigorous assessment of technical factors that impact SNV identification in viral samples and establishes heuristics that will inform and improve future studies of intra-host variation, viral diversity, and viral evolution. IMPORTANCE When viruses replicate inside a host cell, the virus replication machinery makes mistakes. Over time, these mistakes create mutations that result in a diverse population of viruses inside the host. Mutations that are neither lethal to the virus nor strongly beneficial can lead to minority variants that are minor members of the virus population. However, preparing samples for sequencing can also introduce errors that resemble minority variants, resulting in the inclusion of false-positive data if not filtered correctly. In this study, we aimed to determine the best methods for identification and quantification of these minority variants by testing the performance of seven commonly used variant-calling tools. We used simulated and synthetic data to test their performance against a true set of variants and then used these studies to inform variant identification in data from SARS-CoV-2 clinical specimens. Together, analyses of our data provide extensive guidance for future studies of viral diversity and evolution.
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COVID-19 , Orthomyxoviridae , Virus , Humanos , SARS-CoV-2/genética , Mutación , Secuenciación de Nucleótidos de Alto Rendimiento/métodosRESUMEN
INTRODUCTION: This study focuses on the nutrition of young people in schools. The Saarland state government mandates the implementation of the "quality standards for school meals", developed by the Germany Society of Nutrition (Deutschen Gesellschaft für Ernährung, DGE) in schools offering school meals. This research evaluates the state of implementation. METHODS: 4-week menu plans were evaluated using a stratified random sample of selected schools (n25%-sample=5, ntotal=23). In addition, all catering services of the district (ncaterer=5) were interviewed by written survey focused on any information on the company, the type of food, the menu design as well as general information. RESULTS: None of the analysed menu plans met the DGE standard. The analysis of the menu plans allows for an assessment of the nutritional quality of food. Interviews with caterers provide background information on menu design. DISCUSSION: The analysis of a randomised 25%-sample shows that the target specifications of the DGE are only implemented by a small number of schools in the exemplary selected district of St. Wendel, Germany. As the German Child and Youth Health Survey (KiGGS), also this evaluation shows that the quality of school meals deviates significantly from the recommendations of the DGE. There is a clear need for action.
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Alimentos/normas , Adhesión a Directriz/estadística & datos numéricos , Guías como Asunto , Comidas , Planificación de Menú/normas , Instituciones Académicas/estadística & datos numéricos , Instituciones Académicas/normas , Alemania/epidemiología , Restaurantes/normas , Restaurantes/estadística & datos numéricosRESUMEN
A new method of endometrial ablation has been presented. This is the method of bipolar tridimensional device "NOVA SURE". This innovative method enables to destruct the basal and functional layer of the uterus and thus leads to amenorrhea and hypomenorrhea.
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Endometrio/cirugía , Histerectomía/métodos , Hemorragia Uterina/cirugía , Adulto , Femenino , Humanos , Histerectomía/instrumentación , Persona de Mediana Edad , Útero/cirugíaRESUMEN
High error rates of viral RNA-dependent RNA polymerases lead to diverse intra-host viral populations during infection. Errors made during replication that are not strongly deleterious to the virus can lead to the generation of minority variants. However, accurate detection of minority variants in viral sequence data is complicated by errors introduced during sample preparation and data analysis. We used synthetic RNA controls and simulated data to test seven variant calling tools across a range of allele frequencies and simulated coverages. We show that choice of variant caller, and use of replicate sequencing have the most significant impact on single nucleotide variant (SNV) discovery and demonstrate how both allele frequency and coverage thresholds impact both false discovery and false negative rates. We use these parameters to find minority variants in sequencing data from SARS-CoV-2 clinical specimens and provide guidance for studies of intrahost viral diversity using either single replicate data or data from technical replicates. Our study provides a framework for rigorous assessment of technical factors that impact SNV identification in viral samples and establishes heuristics that will inform and improve future studies of intrahost variation, viral diversity, and viral evolution. IMPORTANCE: When viruses replicate inside a host, the virus replication machinery makes mistakes. Over time, these mistakes create mutations that result in a diverse population of viruses inside the host. Mutations that are neither lethal to the virus, nor strongly beneficial, can lead to minority variants that are minor members of the virus population. However, preparing samples for sequencing can also introduce errors that resemble minority variants, resulting in inclusion of false positive data if not filtered correctly. In this study, we aimed to determine the best methods for identification and quantification of these minority variants by testing the performance of seven commonly used variant calling tools. We used simulated and synthetic data to test their performance against a true set of variants, and then used these studies to inform variant identification in data from clinical SARS-CoV-2 clinical specimens. Together, analyses of our data provide extensive guidance for future studies of viral diversity and evolution.
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Increasing awareness of the adverse health effects of air pollution leads to a demand of low-cost sensors for the measurement of pollutants such as NO2. However, commercially available low-cost sensors lack accuracy and long-term stability, and suffer from cross-sensitivity to other gases. These drawbacks can be overcome by the method of quartz-enhanced photoacoustic spectroscopy (QEPAS). In QEPAS modulated light is absorbed by the NO2 molecules, which results in the production of a sound wave. The sound wave is detected by resonance of a quartz tuning fork, which results in a measurable electric signal. Due to the small size of the tuning forks, the gas sensing element can be smaller than 1â¯cm3. We present the first bare fork QEPAS setup for the ppb-level detection of NO2, which is ideally suited for environmental trace gas detection without the need of using micro-resonators. Micro-resonators are commonly used to amplify photoacoustic signals. However, micro-resonators have different dependencies on environmental conditions than tuning forks, which makes them difficult to operate in changing conditions. In contrast, our bare fork QEPAS setup is more robust and easily adopted by the use of a low-cost temperature and humidity sensor. By using acoustic filters the integration time could be increased to offer higher sensitivity at a continuous flow rate of 200â¯stdâ¯cm3â¯min-1. The 1σ noise equivalent concentration is determined to 21â¯ppb NO2 in synthetic air for 120â¯s measurement time, allowing detection which satisfies international health and safety standards thresholds.
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BACKGROUND: Pneumonia accounts for approximately 2 million deaths annually among children aged <5 years, with most of these deaths occurring in Africa and southern Asia. The South Asian Pneumococcal Alliance (SAPNA) network in Nepal is generating local epidemiological data to assist in the development of national and regional policies for prevention of pneumococcal and Haemophilus influenzae (Hib) disease. METHODS: Children aged 2 months to 5 years with suspected invasive bacterial disease were recruited from Kanti Children Hospital, Kathmandu, Nepal. Specimens of blood, CSF, and normally sterile body fluids were cultured, and analysis of antimicrobial susceptibility patterns and serotyping of Streptococcus pneumoniae isolates were performed. CSF specimens were also tested for S. pneumoniae and Hib antigens by a latex agglutination test and an immunochromatographic test of pneumococcal antigen (NOW S. pneumoniae Antigen Test; Binax). RESULTS: A total of 2528 children with suspected invasive bacterial disease were recruited, of whom 82% had pneumonia, 9.6% had meningitis, 2% had very severe disease, and 0.4% had bacteremia; the remainder received another diagnosis. Before hospitalization, 26.7% had received antibiotic treatment. Fifty children had S. pneumoniae identified as the etiological agent of invasive disease. Of 2461 blood cultures performed, 22 were positive for S. pneumoniae. Of 33 cases of S. pneumoniae meningitis, 11 were detected by CSF culture, and 21 were detected by latex agglutination and pneumococcal antigen tests. The rate of detection of S. pneumoniae in CSF was 3.6% by culture, compared with 7.8% by latex agglutination and 10% by pneumococcal antigen testing. The rate of detection of H. influenzae in CSF was 1.7% by culture and 6.5% by latex agglutination. The most common serotypes found were 1, 5, 2, and 7F, followed by 12A, 19B, and 23F. Of all the invasive isolates, 3.8% were resistant to penicillin, and 68% were resistant to trimethoprim-sulfamethoxazole. CONCLUSIONS: The SAPNA network has identified Hib and pneumococci as causes of significant disease in Nepal.
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Infecciones Neumocócicas/epidemiología , Streptococcus pneumoniae/aislamiento & purificación , Antibacterianos/farmacología , Antígenos Bacterianos/líquido cefalorraquídeo , Bacteriemia/epidemiología , Bacteriemia/microbiología , Sangre/microbiología , Líquido Cefalorraquídeo/microbiología , Niño Hospitalizado , Preescolar , Cromatografía de Afinidad , Farmacorresistencia Bacteriana , Humanos , Lactante , Recién Nacido , Pruebas de Fijación de Látex , Meningitis Neumocócica/epidemiología , Pruebas de Sensibilidad Microbiana , Nepal/epidemiología , Neumonía Neumocócica/epidemiología , Prevalencia , Serotipificación , Streptococcus pneumoniae/clasificaciónRESUMEN
A 51 year old man with an innominate artery aneurysm presented with claudication and ischemia of the right forearm and hand. Two-dimensional echocardiography visualized the saccular aneurysm and a pedunculated mobile thrombus within it that were not seen during aortic arch angiography. Two-dimensional echocardiography, shown to be useful in identifying intracardiac masses and aortic aneurysms, may be important in selecting patients with increased risk of embolization.
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Aneurisma/diagnóstico , Tronco Braquiocefálico , Ecocardiografía/métodos , Trombosis/diagnóstico , Brazo/irrigación sanguínea , Humanos , Isquemia , Masculino , Persona de Mediana EdadRESUMEN
Alterations in left ventricular filling can occur with aging and in patients with hypertension, ischemic heart disease, congestive and hypertrophic cardiomyopathy and congenital heart disease. This study examines the effects of blood pressure on left ventricular diastolic filling indexes measured by Doppler ultrasound technique in 47 young normotensive adolescents (mean age 13 years). Left ventricular filling was assessed by Doppler peak early and late diastolic transmitral flow velocities, early and late diastolic flow velocity integrals and early diastolic deceleration. Systolic blood pressure did not correlate with any of the Doppler filling indexes, although it was related to echocardiographic left ventricular mass (r = 0.44, p less than 0.005). Diastolic blood pressure did not correlate with left ventricular mass; however, it was inversely related to peak early diastolic flow velocity (r = -0.44, p less than 0.005), early diastolic flow velocity integral (r = -0.40, p less than 0.01) and early diastolic deceleration (r = -0.32, p less than 0.05). The ratio of late to early peak filling (A/E) was directly related to diastolic blood pressure (r = 0.48, p less than 0.001). Examination of electrocardiograms showed that there was a stronger correlation between A/E ratio and diastolic blood pressure (r = 0.63) in 22 subjects with bimodal P waves in lead V1 than in subjects with unimodal P waves (r = 0.45).(ABSTRACT TRUNCATED AT 250 WORDS)
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Presión Sanguínea , Ecocardiografía , Corazón/fisiología , Adolescente , Velocidad del Flujo Sanguíneo , Niño , Diástole , Electrocardiografía , Femenino , Corazón/fisiopatología , Frecuencia Cardíaca , Humanos , Hipertensión/diagnóstico , Masculino , Valores de Referencia , Función VentricularRESUMEN
This study compared the effectiveness of sterilizing four types of endoscope using different models of the Sterrad system (Sterrad 50, 100, 100S and 200). Sterilization levels meeting international requirements were attained in all cases with carriers inoculated with Geobacillus stearothermophilus spores. The endoscopes were tested in half cycles ('overkill'). This is the first study to compare the Sterrad models marketed to date in terms of effective sterilization of endoscopes with narrow lumens.
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Infección Hospitalaria/prevención & control , Desinfectantes/farmacología , Endoscopios Gastrointestinales/microbiología , Contaminación de Equipos/prevención & control , Peróxido de Hidrógeno/farmacología , Esterilización/métodos , Recuento de Colonia Microbiana , Equipos y Suministros/microbiología , Geobacillus stearothermophilus/efectos de los fármacos , Humanos , Control de Infecciones/métodos , Esterilización/instrumentación , TemperaturaRESUMEN
Abnormalities in left ventricular (LV) wall thickness and mass have been demonstrated in patients with mild hypertension utilizing M-mode echocardiography. In addition, studies using radionuclide angiography have demonstrated abnormalities in early diastolic LV filling in asymptomatic hypertensive patients with normal ejection fraction and cardiac output. Recently, Doppler recordings of flow velocity in the ascending aorta and through the mitral valve have been shown to provide useful information about LV function. To determine whether flow abnormalities could be detected in patients with mild hypertension, we recorded Doppler aortic and mitral valve flow velocities in 21 men with mild hypertension. Casual systolic blood pressure was 147 +/- 18 mm Hg (mean +/- SD) and diastolic blood pressure was 96 +/- 9 mm Hg. LV mass (310 +/- 75 g) was elevated (i.e., above the 95% normal prediction interval) in 8 of 19 patients who underwent M-mode echocardiography; LV ejection fraction was normal in all patients (mean, 80%). As in previous studies in normal subjects, we found in these hypertensive patients an inverse correlation between age and both aortic peak flow velocity (r = -0.51, p less than 0.05) and transmitral early diastolic peak flow velocity (r = -0.44, p less than 0.05) and a positive relationship between age and mitral valve late diastolic peak flow velocity (r = 0.73, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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Ecocardiografía/métodos , Hipertensión/diagnóstico , Adulto , Anciano , Diástole , Ventrículos Cardíacos/patología , Ventrículos Cardíacos/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , UltrasonografíaRESUMEN
A randomized, double-blind, crossover study was performed to evaluate the efficacy and tolerance of ethmozine, propranolol and a combination of ethmozine and propranolol for treatment of ventricular arrhythmias. Twenty-six patients received propranolol, 40 mg, or matching placebo 3 times daily, alone or in combination with ethmozine, 600 to 900 mg/day in 3 equally divided doses, for 1-week periods separated by matching placebo. As determined by 48-hour weekly Holter monitoring, the mean reduction in ventricular premature complex (VPC) frequency was significantly greater with ethmozine (86%) and with ethmozine plus propranolol (90%) than with propranolol (41%) (p less than 0.05). Seventy-five percent of patients had more than a 70% reduction in VPCs with ethmozine plus propranolol, although 70% of patients had an equal degree of suppression with ethmozine alone. Only 2 patients (10%) had the same degree of VPC suppression with propranolol. The results were similar for reductions in pairs of VPCs and VT runs. Two patients discontinued propranolol because of adverse effects, but no patient discontinued ethmozine or combination therapy. Adverse effects were not more frequent with combination therapy. Ventricular function as assessed by echocardiography during drug dosing showed no significant changes from placebo. Ethmozine alone or in combination with propranolol was effective in suppressing VPCs for as long as 1 year in patients who responded. It is concluded that ethmozine alone or in combination with propranolol is well tolerated. Propranolol does not appear to enhance the efficacy of ethmozine.
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Antiarrítmicos/uso terapéutico , Complejos Cardíacos Prematuros/tratamiento farmacológico , Fenotiazinas/uso terapéutico , Propranolol/uso terapéutico , Taquicardia/tratamiento farmacológico , Ensayos Clínicos como Asunto , Método Doble Ciego , Quimioterapia Combinada , Electrocardiografía , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico , Moricizina , Distribución AleatoriaRESUMEN
In the investigation of new antiarrhythmic drugs, comparative trials with clinically available antiarrhythmic agents provide a perspective from which to judge the new investigational agent. Two clinical investigations of moricizine HCl, each using a placebo-controlled, double-blind, crossover design, are summarized. In the first study, 18 patients with greater than or equal to 30 ventricular premature complexes (VPCs) per hour (mean 369 +/- 95) were given propranolol (120 mg daily) compared with moricizine HCl (816 +/- 103 mg daily). Propranolol suppressed 38% of VPCs in the study group, moricizine HCl, 81% of VPCs, and the combination of both drugs, 87%. Moricizine HCl was more effective than propranolol in suppressing VPCs at all individual levels greater than 70% (p less than 0.05, McNemar's test). The combination of moricizine HCl and propranolol was well tolerated. The second investigation used a placebo-controlled, double-blind, crossover design to compare the efficacy of disopyramide (600 mg daily) and moricizine HCl (800 mg daily) in 27 patients. Patients had greater than or equal to 40 VPCs/hr on a 24-hour ambulatory electrocardiogram. During moricizine HCl administration, the mean VPC frequency decreased from 524 to 151 VPCs/hr (71.2% reduction). In contrast, disopyramide reduced VPC frequency from 535 to 253 VPCs/hr (52.8% reduction) and demonstrated significantly greater side effects (p less than 0.05). Moricizine HCl was more effective than disopyramide in suppressing VPCs at all individual percent reduction levels greater than 70% (p less than 0.05, McNemar's test). Moricizine HCl was more effective in suppressing VPCs than either disopyramide or propranolol, with significantly fewer side effects.
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Antiarrítmicos/uso terapéutico , Arritmias Cardíacas/tratamiento farmacológico , Fenotiazinas/uso terapéutico , Adulto , Anciano , Antiarrítmicos/sangre , Arritmias Cardíacas/fisiopatología , Ensayos Clínicos como Asunto , Disopiramida/sangre , Disopiramida/uso terapéutico , Método Doble Ciego , Electrocardiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Moricizina , Fenotiazinas/sangre , Propranolol/uso terapéutico , Distribución AleatoriaRESUMEN
Pulsed Doppler mitral flow velocity measurements have been used to evaluate left ventricular diastolic filling. In normal persons these measurements are affected by age and respiration, but not by gender, body surface area or normal blood pressure. Additional factors that may influence these measurements include the imaging view and sample volume location. In this study, the effects of imaging view and sample volume location were evaluated in 52 normal subjects, aged 21 to 78 years. Pulsed Doppler recordings were obtained from the apical 4-chamber and apical 2-chamber views with the sample volume located both in the left atrium and at the level of the mitral valve leaflet tips. Doppler measurements were slightly, but not significantly, higher (4% on average) for recordings obtained from the apical 4-chamber than from the 2-chamber view for peak flow velocity in both early and late diastole. However, apical 4-chamber recordings from a sample volume in the left atrium resulted in measurements significantly lower (p less than 0.05) for both early and late diastolic mitral peak flow velocity than those obtained near the mitral leaflet tips (peak flow velocity in early diastole = 43 +/- 12 vs 57 +/- 12 cm/s and peak flow velocity in late diastole = 36 +/- 7 vs 46 +/- 11 cm/s, respectively). The higher mitral peak flow velocity values recorded in early and late diastole near the mitral leaflet tips may be related to the smaller flow area at the mitral valve orifice compared with the left atrium.(ABSTRACT TRUNCATED AT 250 WORDS)
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Ecocardiografía , Válvula Mitral/fisiología , Adulto , Anciano , Velocidad del Flujo Sanguíneo , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
A miniaturized on-line monitoring system for the detection of L-lactate and glucose is presented. The system is based on a microfabricated multi-enzyme silicon sensor chip with flow channels integrated on the chip. The sensors were fabricated in containment technology. They were characterized in test solutions. The cross-talking behaviour was investigated and was found to be practically negligible. The linear measurement ranges of both glucose and lactate sensors were large enough for most practical applications. As a result of the miniaturization the analyte consumption could be reduced to a few nmol min(-1). The system was equipped with a microdialysis probe whose recovery was 45% for lactate and 37% for glucose in test solutions using a flow rate of 3 microl min(-1). Lower flow rates of 0.5 microl min(-1) resulted in recoveries of over 90%. The long-term stability of the system was acceptable. Initial measurements have also been performed in vitro using human blood serum.
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Técnicas Biosensibles/instrumentación , Glucosa/análisis , Ácido Láctico/análisis , Técnicas Biosensibles/estadística & datos numéricos , Glucemia/análisis , Humanos , Técnicas In Vitro , Ácido Láctico/sangre , Microdiálisis , Monitoreo Fisiológico/instrumentación , Sistemas en Línea , Sensibilidad y Especificidad , SilicioRESUMEN
This paper reports some new results on enzyme based silicon containment sensors. For the first time an L-lactate sensor in containment technology is presented. Through optimization of the buffer system the stability of the lactate sensor was enhanced and the linear response of over 10 mM was achieved. The glucose sensor has also been optimized for a large linear measurement range exceeding 30 mM. A two-enzyme chip with glucose and lactate sensor elements which were integrated on one silicon chip is presented. The response behaviour of the two-enzyme chip was very similar to the single chip behaviour. No cross-talking effects could be observed. A fabrication process for mass-production is described.