Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 20 de 51
Filtrar
1.
Lett Appl Microbiol ; 74(3): 354-366, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34784062

RESUMEN

Indole-3-acetic acid (IAA) synthesis is a major property of rhizosphere bacteria. The IAA-producing ability of rhizobacteria may be influenced by agricultural management. We therefore evaluated the IAA-producing potential of rhizobacteria isolated during organic rice farming (ORF) and conventional rice farming (CRF) in Thung Kula Rong Hai areas of Thailand. The results indicated that ORF gave a significantly higher percentage of IAA producers (95·8%) than CRF (69·9%). The average IAA values of the ORF isolates were around two times higher than those of the CRF isolates both in the absence (12·8 and 5·8 µg IAA ml-1 , respectively) and presence of L-tryptophan (L-Trp) (35·2 and 17·2 µg IAA ml-1 , respectively). The 16S rRNA gene sequence analysis indicated that the 23 selected isolates belonged to 8 different genera-Sinomonas sp., Micrococcus sp., Microbacterium sp., Fictibacillus sp., Bacillus sp., Burkholderia sp., Leclercia sp. and Enterobacter sp. Interestingly, only three ORF isolates, i.e. ORF15-20 (Micrococcus sp.), ORF15-21 (Sinomonas sp.) and ORF15-23 (Sinomonas sp.), exhibited high IAA production ability without L-Trp (128·5, 160·8 and 174·7 µg IAA ml-1 , respectively). Meanwhile, a slight decrease in IAA production with L-Trp was noticed, suggesting that the L-Trp was not used for the IAA synthesis of these isolates. Biopriming with rhizobacterial isolates significantly enhanced the rate of germination of KDML 105 rice seeds compared to the control.


Asunto(s)
Oryza , Enterobacter , Ácidos Indolacéticos , ARN Ribosómico 16S/genética
2.
J Sex Med ; 18(3): 632-645, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33642235

RESUMEN

BACKGROUND: The number of adolescents presenting with gender dysphoria (GD) in healthcare services has increased significantly, yet specialized services offering transition-related care (TRC) for trans youth is lacking. AIM: To investigate satisfaction with TRC, regret, and reasons for (dis)satisfaction with transition-related medical interventions (TRMIs) in trans adolescents who had presented to the Hamburg Gender Identity Service for children and adolescents (Hamburg GIS). METHODS: Data were collected from a clinical cohort sample of 75 adolescents and young adults diagnosed with GD (81% assigned female at birth) aged 11 to 21 years (M = 17.4) at baseline and follow-up (on a spectrum of ongoing care, on average 2 years after initial consultation). To determine progress of the youth's medical transitions, an individual treatment progress score (ITPS) was calculated based on number of desired vs received TRMIs. OUTCOMES: Main outcome measures were satisfaction with TRC at the time of follow-up, ITPS, social support, reasons for regret and termination of TRC, and (dis)satisfaction with TRMIs. RESULTS: Participants underwent different stages of TRMIs, such as gender-affirming hormone treatment or surgeries, and showed overall high satisfaction with TRC received at the Hamburg GIS. Regression analysis indicated that a higher ITPS (an advanced transition treatment stage) was predictive of higher satisfaction with TRC. Sex assigned at birth, age, and time since initial consultation at the clinic showed no significant effects for satisfaction with TRC, while degree of social support showed a trend. No adolescents regretted undergoing treatment at follow-up. Additional analysis of free-text answers highlighted satisfaction mostly with the physical results of TRMI. CLINICAL IMPLICATIONS: Because youth were more satisfied with TRC when their individual transition (ITPS) was more progressed, treatment should start in a timely manner to avoid distress from puberty or long waiting lists. STRENGTHS AND LIMITATIONS: This study is one of the first to report on treatment satisfaction among youth with GD from Europe. The ITPS allowed for a more detailed evaluation of TRMI wishes and experiences in relation to satisfaction with TRC and may close a gap in research on these treatments in adolescent populations. However, all participants were from the same clinic, and strict treatment eligibility criteria may have excluded certain trans adolescents from the study. Low identification rates with non-binary identities prevented comparisons between non-binary and binary genders. CONCLUSION: The study highlights the role of TRMI and individual treatment or transition progress for youth's overall high satisfaction with TRC received at the Hamburg GIS. Nieder TO, Mayer TK, Hinz S, et al. Individual Treatment Progress Predicts Satisfaction With Transition-Related Care for Youth With Gender Dysphoria: A Prospective Clinical Cohort Study. J Sex Med 2021;18:632-645.


Asunto(s)
Disforia de Género , Personas Transgénero , Adolescente , Adulto , Niño , Estudios de Cohortes , Europa (Continente) , Femenino , Disforia de Género/terapia , Identidad de Género , Humanos , Masculino , Satisfacción Personal , Estudios Prospectivos , Adulto Joven
3.
Psychol Med ; 50(10): 1727-1735, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-31328716

RESUMEN

BACKGROUND: Previous research showed that automatic emotion regulation is associated with activation of subcortical areas and subsequent feedforward processes to cortical areas. In contrast, cognitive awareness of emotions is mediated by negative feedback from cortical to subcortical areas. Pregenual anterior cingulate cortex (pgACC) is essential in the modulation of both affect and alexithymia. We considered the interplay between these two mechanisms in the pgACC and their relationship with alexithymia. METHOD: In 68 healthy participants (30 women, age = 26.15 ± 4.22) we tested associations of emotion processing and alexithymia with excitation/inhibition (E/I) balance represented as glutamate (Glu)/GABA in the pgACC measured via magnetic resonance spectroscopy in 7 T. RESULTS: Alexithymia was positively correlated with the Glu/GABA ratio (N = 41, p = 0.0393). Further, cognitive self-awareness showed an association with Glu/GABA (N = 52, p = 0.003), which was driven by a correlation with GABA. In contrast, emotion regulation was only correlated with glutamate levels in the pgACC (N = 49, p = 0.008). CONCLUSION: Our results corroborate the importance of the pgACC as a mediating region of alexithymia, reflected in an altered E/I balance. Furthermore, we could specify that this altered balance is linked to a GABA-related modulation of cognitive self-awareness of emotions.


Asunto(s)
Síntomas Afectivos/metabolismo , Regulación Emocional/fisiología , Giro del Cíngulo/fisiología , Inhibición Psicológica , Adulto , Mapeo Encefálico , Cognición , Femenino , Ácido Glutámico/análisis , Voluntarios Sanos , Humanos , Espectroscopía de Resonancia Magnética , Masculino , Adulto Joven , Ácido gamma-Aminobutírico/análisis
4.
Opt Express ; 21(26): 32377-85, 2013 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-24514830

RESUMEN

The strong enhancement of electrical fields in subnanometer gaps of self-assembled gold nanoparticle clusters holds great promise for large scale fabrication of sensitive optical sensing substrates. Due to the large number of involved nanoparticles, however, their optical response is complex and not easily accessible through numerical simulations. Here, we use hyperspectral supercontinuum spectroscopy to demonstrate how confined optical modes of well defined energies are supported by different areas of the cluster. Due to the strong resonant coupling in those regions, the cluster essentially acts as a nanoscale optical sieve which sorts incident light according to its wavelength.


Asunto(s)
Oro/química , Nanopartículas del Metal/química , Nanopartículas del Metal/ultraestructura , Resonancia por Plasmón de Superficie/métodos , Luz , Ensayo de Materiales , Dispersión de Radiación
5.
J Prev Alzheimers Dis ; 10(4): 790-799, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37874101

RESUMEN

BACKGROUND: While the U.S. National Institute on Aging has developed a strategy for recruitment of minority populations in dementia research, including increasing awareness and engagement, minority populations remain under-represented, and the evidence-base is limited. We tested a conceptually driven communication approach targeting barriers and facilitators to research participation vs. standard education. METHODS: In this 2-phase project, input from the minority advisory board of the Cleveland Alzheimer's Disease Research Center informed development of 2 brief health communication videos which differentially focused on research barriers and facilitators (POWER) versus an education control (Phase 1). In Phase 2, a randomized prospective survey compared POWER vs. an active comparator control on pre/post video change in dementia knowledge, cumulative barriers, and facilitators to dementia research, and change in research readiness measured by the Transtheoretical behavior change model. Changes in outcomes were evaluated using two group by two time points repeated measure analysis of variance (RMANOVA) controlling for age, gender, race, and education. RESULTS: The pre-video sample (n=242) had mean age of 57.6 (SD17.2) years, mostly female (n=181, 74.8%), 42.6% non-white. The analyzable sample who completed both pre and post assessments comprised n=102 in the POWER and n=105 in the control group. Non-white participants made up 41.1% of the analyzable POWER (n=51) and 44.1% (n= 52) of controls. Adjusted for age, gender, race and education, controls had a greater increase in dementia knowledge (p=0.004). There was a significant reduction in barriers for POWER (p=.044) vs. control. There were no differences in research facilitators and research readiness between POWER vs. control. Among African Americans (n=59, 28.5% of the analyzable sample) there was a trend for improved dementia knowledge (p=.059) favoring control and in research readiness (p=.051), favoring POWER. CONCLUSIONS: Targeting barriers and attitudes towards research could inform development of approaches with potential to improve dementia research participation across diverse communities.


Asunto(s)
Demencia , Comunicación en Salud , Humanos , Femenino , Persona de Mediana Edad , Masculino , Estudios Prospectivos , Escolaridad
6.
Nat Commun ; 14(1): 3651, 2023 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-37339976

RESUMEN

Astrocyte dysfunction has previously been linked to multiple neurodegenerative disorders including Parkinson's disease (PD). Among their many roles, astrocytes are mediators of the brain immune response, and astrocyte reactivity is a pathological feature of PD. They are also involved in the formation and maintenance of the blood-brain barrier (BBB), but barrier integrity is compromised in people with PD. This study focuses on an unexplored area of PD pathogenesis by characterizing the interplay between astrocytes, inflammation and BBB integrity, and by combining patient-derived induced pluripotent stem cells with microfluidic technologies to generate a 3D human BBB chip. Here we report that astrocytes derived from female donors harboring the PD-related LRRK2 G2019S mutation are pro-inflammatory and fail to support the formation of a functional capillary in vitro. We show that inhibition of MEK1/2 signaling attenuates the inflammatory profile of mutant astrocytes and rescues BBB formation, providing insights into mechanisms regulating barrier integrity in PD. Lastly, we confirm that vascular changes are also observed in the human postmortem substantia nigra of both males and females with PD.


Asunto(s)
Barrera Hematoencefálica , Enfermedad de Parkinson , Masculino , Humanos , Femenino , Barrera Hematoencefálica/patología , Astrocitos/patología , Enfermedad de Parkinson/patología , Encéfalo/patología , Sustancia Negra/patología
7.
Psychol Med ; 42(6): 1195-202, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22030013

RESUMEN

BACKGROUND: Neuropsychological impairment is a key feature of late-life depression, with deficits observed across multiple domains. However, it is unclear whether deficits in multiple domains represent relatively independent processes with specific neural correlates or whether they can be explained by cognitive deficits in executive function or processing speed. METHOD: We examined group differences across five domains (episodic memory; executive function; language skills; processing speed; visuospatial skills) in a sample of 36 depressed participants and 25 control participants, all aged ≥ 60 years. The influence of executive function and processing speed deficits on other neuropsychological domains was also investigated. Magnetic resonance imaging correlates of executive function, processing speed and episodic memory were explored in the late-life depression group. RESULTS: Relative to controls, the late-life depression group performed significantly worse in the domains of executive function, processing speed, episodic memory and language skills. Impairments in executive function or processing speed were sufficient to explain differences in episodic memory and language skills. Executive function was correlated with anisotropy of the anterior thalamic radiation and uncinate fasciculus; processing speed was correlated with anisotropy of genu of the corpus callosum. Episodic memory was correlated with anisotropy of the anterior thalamic radiation, the genu and body of the corpus callosum and the fornix. CONCLUSIONS: Executive function and processing speed appear to represent important cognitive deficits in late-life depression, which contribute to deficits in other domains, and are related to reductions in anisotropy in frontal tracts.


Asunto(s)
Encéfalo/fisiopatología , Trastornos del Conocimiento/fisiopatología , Trastorno Depresivo/fisiopatología , Neuropsicología , Factores de Edad , Anciano , Anisotropía , Mapeo Encefálico , Estudios de Casos y Controles , Función Ejecutiva/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Memoria Episódica , Persona de Mediana Edad , Pruebas Neuropsicológicas/estadística & datos numéricos , Tiempo de Reacción/fisiología , Índice de Severidad de la Enfermedad
8.
Phys Rev Lett ; 104(2): 026801, 2010 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-20366615

RESUMEN

We report on conductance measurements in carbon nanotube based double quantum dots connected to two normal electrodes and a central superconducting finger. By operating our devices as beam splitters, we provide evidence for crossed Andreev reflections tunable in situ. This opens an avenue to more sophisticated quantum opticslike experiments with spin entangled electrons.

9.
J Neurol Neurosurg Psychiatry ; 79(6): 619-24, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17717021

RESUMEN

BACKGROUND: White matter hyperintensities in MRI scans are age related but appear to be more prevalent in depressed patients. They may be more pronounced in late onset depression. This finding, if confirmed, would potentially illuminate the heterogeneity of depression in elderly subjects. METHODS: We conducted a systematic literature search of studies investigating white matter changes in late life depression, identifying 98 studies. The 30 remaining eligible studies were scrutinised for the presence and severity measures of periventricular and deep white matter changes in late life, late onset and, if available, early onset depression as well as in controls. Comparisons between groups were entered into random effects meta-analyses using odds ratios and Cohen's d, as appropriate. Correlations with potential confounders, such as age difference between groups, were explored. RESULTS: Late life depression and, to a greater extent, late onset depression in late life were characterised by more frequent and intense white matter abnormalities. In particular, the odds of having white matter changes were over 4 for late compared with early onset depression. Similarly, on severity scales, late onset depression had scores of 0.7-0.8 standard deviations above early onset patients. CONCLUSIONS: Significant differences between early and late onset depression suggest different aetiological mechanisms, in accordance with a theory of "cerebrovascular" depression of late onset. Greater duration of depressive symptoms, signs and treatment does not appear to have a measurable impact on white matter signal in MRI scans.


Asunto(s)
Encéfalo/patología , Trastorno Depresivo Mayor/diagnóstico , Trastorno Depresivo/diagnóstico , Imagen por Resonancia Magnética , Fibras Nerviosas Mielínicas/patología , Edad de Inicio , Anciano , Ventrículos Cerebrales/patología , Trastornos Cerebrovasculares/diagnóstico , Trastornos Cerebrovasculares/patología , Trastorno Depresivo/patología , Trastorno Depresivo Mayor/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad
10.
J Colloid Interface Sci ; 475: 36-45, 2016 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-27153216

RESUMEN

The electrostatic charge density of particles is of paramount importance for the control of the dispersion stability. Conventional methods use potentiometric, conductometric or turbidity titration but require large amount of samples. Here we report a simple and cost-effective method called polyelectrolyte assisted charge titration spectrometry or PACTS. The technique takes advantage of the propensity of oppositely charged polymers and particles to assemble upon mixing, leading to aggregation or phase separation. The mixed dispersions exhibit a maximum in light scattering as a function of the volumetric ratio X, and the peak position XMax is linked to the particle charge density according to σ∼D0XMax where D0 is the particle diameter. The PACTS is successfully applied to organic latex, aluminum and silicon oxide particles of positive or negative charge using poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate). The protocol is also optimized with respect to important parameters such as pH and concentration, and to the polyelectrolyte molecular weight. The advantages of the PACTS technique are that it requires minute amounts of sample and that it is suitable to a broad variety of charged nano-objects.

11.
Int J Impot Res ; 28(5): 172-5, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27225710

RESUMEN

The majority of medical students and medical healthcare providers do not feel comfortable when addressing sexual problems. It was suggested that more courses in sexual health are needed at medical schools to overcome this shortcoming. To assess medical students' interest in and attitude about sexual health education at medical schools in Germany, a 13-item online questionnaire was developed. The link to the questionnaire was distributed at all medical schools in Germany. In total, 3264 medical students (69.9% female) from all 37 medical schools in Germany participated. Students from all universities indicated that contents related to sexual health are taught at their university. The majority (n=1809; 62.1%) answered that courses in sexual health should be mandatory. The types of educational experiences that were viewed as most appropriate were lectures (n=2281, 78.3%) and seminars without patient contact (n=1414, 48.5%). Students were most interested in child sexual abuse and sexually transmitted infections. It should be ensured that all medical students have acquired basic knowledge in diagnosing and treating frequent sexual problems at the end of their medical studies. Suggestions are made about how to improve current efforts of sexual health education at medical schools.


Asunto(s)
Actitud del Personal de Salud , Conocimientos, Actitudes y Práctica en Salud , Salud Reproductiva/educación , Educación Sexual , Adolescente , Adulto , Femenino , Alemania , Encuestas de Atención de la Salud , Humanos , Masculino , Persona de Mediana Edad , Estudiantes de Medicina , Adulto Joven
12.
Oncogene ; 19(34): 3894-901, 2000 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-10951583

RESUMEN

Mutations of the tumor suppressor protein APC (Adenomatous Polyposis Coli) are linked to familiar and sporadic human colon cancer. Here we describe a novel interaction between the APC protein and the protein tyrosine phosphatase PTP-BL carrying five PDZ protein-protein interaction domains. Exclusively, the second PDZ domain (PDZ2) of PTP-BL is binding to the extreme C-terminus of the APC protein, as determined by yeast two-hybrid studies. Using surface plasmon resonance analysis we established a dissociation constant (K(D)) of 8.1 x 10(-9) M. We find that a naturally occurring splice insertion of five amino acids (PDZ2b) abolishes its binding affinity to the APC protein. The in vivo interaction between PTP-BL and the APC protein was shown by coprecipitation experiments in transfected COS cells. Furthermore, in cultured epithelial Madine Carnine Kidney cells the subcellular colocalization was demonstrated for the nucleus and also for the tips of cellular extensions. The interaction of the APC protein with a protein tyrosine phosphatase may indirectly modulate the steady state levels of tyrosine phosphorylations of associated proteins, such as beta-catenin playing a major role in the regulation of cell division, migration and cell adhesion.


Asunto(s)
Proteínas del Citoesqueleto/metabolismo , Proteínas Tirosina Fosfatasas/genética , Proteínas Tirosina Fosfatasas/metabolismo , Transactivadores , Proteína de la Poliposis Adenomatosa del Colon , Empalme Alternativo , Secuencia de Aminoácidos , Animales , Sitios de Unión , Células COS , Línea Celular , Proteínas del Citoesqueleto/genética , Perros , Células Epiteliales/metabolismo , Humanos , Ratones , Datos de Secuencia Molecular , Pruebas de Precipitina , ARN Mensajero , Resonancia por Plasmón de Superficie , Transfección , Técnicas del Sistema de Dos Híbridos , beta Catenina
13.
Biochim Biophys Acta ; 1479(1-2): 147-54, 2000 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-11004536

RESUMEN

Transmission studies in transmissible spongiform encephalopathies (TSEs) have become increasingly important due to the possible transmission of bovine spongiform encephalopathy to humans resulting in new variant Creutzfeldt-Jacob disease. The horizontal transmission of scrapie, a TSE of sheep, is poorly understood. Possible sources of horizontal transmission are the submandibular and parotid salivary glands. TSEs like natural sheep scrapie are characterized by the conversion of a normal protease sensitive prion protein, PrP(c), to an abnormal protease resistant prion protein, PrP(Sc). Since the presence of PrP(Sc) is an indicator of disease, the salivary glands of scrapie-infected sheep were examined for the presence of PrP(Sc). Although PrP(c) mRNA was detected in the salivary glands, PrP(Sc) was not found in the salivary glands of scrapie-infected sheep. These data suggest that the salivary glands are unlikely sources of horizontal transmission of natural sheep scrapie.


Asunto(s)
Proteínas PrPC/genética , Proteínas PrPSc/genética , ARN Mensajero/genética , Glándulas Salivales/metabolismo , Scrapie/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Bovinos , Cartilla de ADN , Immunoblotting , Inmunohistoquímica , Datos de Secuencia Molecular , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Ovinos
14.
Protein Sci ; 6(3): 657-65, 1997 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9070448

RESUMEN

Thermal denaturation studies as a function of pH were carried out on wild-type iso-1-cytochrome c and three variants of this protein at the solvent-exposed position 73 of the sequence. By examining the enthalpy and Tm at various pH values, the heat capacity increment (delta Cp), which is dominated by the degree of change in nonpolar hydration upon protein unfolding, was found for the wild type where lysine 73 is normally present and for three variants. For the Trp 73 variant, the delta Cp value (1.15 +/- 0.17 kcal/mol K) decreased slightly relative to wild-type iso-1-cytochrome c (1.40 +/- 0.06 kcal/mol K), while for the Ile 73 (1.65 +/- 0.07 kcal/mol K) and the Val 73 (1.50 +/- 0.06 kcal/mol K) variants, delta Cp increased slightly. In previous studies, the Trp 73, Ile 73, and Val 73 variants have been shown to have decreased m-values in guanidine hydrochloride denaturations relative to the wild-type protein (Hermann L, Bowler BE, Dong A, Caughey WS. 1995. The effects of hydrophilic to hydrophobic surface mutations on the denatured state of iso-1-cytochrome c: Investigation of aliphatic residues. Biochemistry 34:3040-3047). Both the m-value and delta Cp are related to the change in solvent exposure upon unfolding and other investigators have shown a correlation exists between these two parameters. However, for this subset of variants of iso-1-cytochrome c, a lack of correlation exists which implies that there may be basic differences between the guanidine hydrochloride and thermal denaturations of this protein. Spectroscopic data are consistent with different denatured states for thermal and guanidine hydrochloride unfolding. The different response of m-values and delta Cp for these variants will be discussed in this context.


Asunto(s)
Grupo Citocromo c/química , Citocromos c , Proteínas de Saccharomyces cerevisiae , Solventes/química , Dicroismo Circular , Grupo Citocromo c/genética , Calor , Mutagénesis Sitio-Dirigida , Desnaturalización Proteica , Termodinámica
15.
Neuroreport ; 9(11): 2457-61, 1998 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-9721914

RESUMEN

The conversion of normal, protease sensitive prion protein (PrP-sen) to the abnormal protease-resistant form (PrP-res) is of central importance in the pathogenesis of scrapie and other transmissible spongiform encephalopathies. In the present study, the effects of reduction of the disulfide bond on the PrP-sen to PrP-res conversion in a cell-free system were examined. The addition of the disulfide reducing agent dithiothreitol inhibited the cell-free conversion reaction with an IC50 of 2-2.5 mM. Separate pretreatment of either PrP-sen or PrP-res with dithiothreitol and an alkylating agent also inhibited the conversion reaction. Results of this study show that preservation of the disulfide bond is important in the conversion of PrP-sen to PrP-res.


Asunto(s)
Priones/química , Alquilación , Animales , Ácido Ascórbico/química , Autorradiografía , Sistema Libre de Células , Cricetinae , Disulfuros/química , Ditionita/química , Ditiotreitol/química , Endopeptidasa K/química , Mesocricetus , Conformación Proteica , Sustancias Reductoras/química , Reactivos de Sulfhidrilo/química
16.
Biomed Tech (Berl) ; 45(4): 90-2, 2000 Apr.
Artículo en Alemán | MEDLINE | ID: mdl-10829542

RESUMEN

Just as the EEG reflects different wake and sleep stages, changes in pupil dynamics reflecting different levels of vigilance are also to be found. The literature contains numerous reports on experimental set-ups for the recording of the pupillogram. Interesting methods of signal processing are to be found in [7] and [5]. Currently, such recordings are being used to check the success of sleep therapy. A problem that still needs solving is the optimal handling of artifacts caused by blinking. The present article proposes a procedure for artifact detection by back-propagation networks, and subsequent reconstruction of the signal by an AR model. Estimation of the signal is first demonstrated by a test signal, and then by a corrupted pupillogram.


Asunto(s)
Parpadeo/fisiología , Electrodiagnóstico/instrumentación , Reflejo Pupilar/fisiología , Procesamiento de Señales Asistido por Computador/instrumentación , Nivel de Alerta/fisiología , Artefactos , Humanos , Red Nerviosa/fisiología
17.
Biomed Tech (Berl) ; 37(4): 69-72, 1992 Apr.
Artículo en Alemán | MEDLINE | ID: mdl-1606296

RESUMEN

Pattern recognition was an important goal in the early work on artificial neural networks. Without arousing dramatic speculation, the paper describes, how a "natural" method of dealing with the configuration of the input layer can considerably improve learning behaviour and classification rate of a modified multi-layered perception with backpropagation of the error learning rule. Using this method, recognition of complex patterns in electrophysiological signals can be performed more accurately, without rules or complicated heuristic procedures. The proposed technique is demonstrated using recognition of the J-point in the ECG as an example.


Asunto(s)
Monitoreo Fisiológico/instrumentación , Redes Neurales de la Computación , Procesamiento de Señales Asistido por Computador/instrumentación , Electrocardiografía/instrumentación , Humanos
20.
Psychol Med ; 39(1): 23-31, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18410701

RESUMEN

BACKGROUND: The dual task paradigm (Baddeley et al. 1986; Della Sala et al. 1995) has been proposed as a sensitive measure of Alzheimer's dementia, early in the disease process. METHOD: We investigated this claim by administering the modified dual task paradigm (utilising a pencil-and-paper version of a tracking task) to 33 patients with amnestic mild cognitive impairment (aMCI) and 10 with very early Alzheimer's disease, as well as 21 healthy elderly subjects and 17 controls with depressive symptoms. All groups were closely matched for age and pre-morbid intellectual ability. RESULTS: There were no group differences in dual task performance, despite poor performance in episodic memory tests of the aMCI and early Alzheimer's disease groups. In contrast, the Alzheimer patients were specifically impaired in the trail-making test B, another commonly used test of divided attention. CONCLUSIONS: The dual task paradigm lacks sensitivity for use in the early differential diagnosis of Alzheimer's disease.


Asunto(s)
Enfermedad de Alzheimer/psicología , Amnesia Retrógrada/psicología , Trastornos del Conocimiento/psicología , Trastorno Depresivo/psicología , Análisis y Desempeño de Tareas , Anciano , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/diagnóstico , Amnesia Retrógrada/complicaciones , Análisis de Varianza , Trastornos del Conocimiento/complicaciones , Trastorno Depresivo/complicaciones , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Memoria a Corto Plazo , Pruebas Neuropsicológicas/estadística & datos numéricos , Valor Predictivo de las Pruebas , Índice de Severidad de la Enfermedad , Prueba de Secuencia Alfanumérica/estadística & datos numéricos
SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda