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1.
J Phys Chem A ; 128(7): 1241-1249, 2024 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-38324399

RESUMEN

The recent implementation of attosecond and few-femtosecond X-ray pump/X-ray probe schemes in large-scale free-electron laser facilities has opened the way to visualize fast nuclear dynamics in molecules with unprecedented temporal and spatial resolution. Here, we present the results of theoretical calculations showing how polarization-averaged molecular-frame photoelectron angular distributions (PA-MFPADs) can be used to visualize the dynamics of hydrogen migration in methanol, ethanol, propanol, and isopropyl alcohol dications generated by X-ray irradiation of the corresponding neutral species. We show that changes in the PA-MFPADs with the pump-probe delay as a result of intramolecular photoelectron diffraction carry information on the dynamics of hydrogen migration in real space. Although visualization of this dynamics is more straightforward in the smaller systems, methanol and ethanol, one can still recognize the signature of that motion in propanol and isopropyl alcohol and assign a tentative path to it. A possible pathway for a corresponding experiment requires an angularly resolved detection of photoelectrons in coincidence with molecular fragment ions used to define a molecular frame of reference. Such studies have become, in principle, possible since the first XFELs with sufficiently high repetition rates have emerged. To further support our findings, we provide experimental evidence of H migration in ethanol-OD from ion-ion coincidence measurements performed with synchrotron radiation.

2.
Clin Microbiol Infect ; 26(10): 1416.e1-1416.e4, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32619735

RESUMEN

OBJECTIVES: To characterize deep skin and soft tissue infections (dSSTI) caused by Panton-Valentine leukocidin (PVL)-positive versus PVL-negative Staphylococcus aureus isolates. METHODS: We performed a retrospective analysis of patients' records including S. aureus isolates from outpatients with dSSTI. Samples had been submitted by primary care physicians, i.e. general practitioners, surgeons, dermatologists and paediatricians, located in Berlin, Germany, in 2007-2017. Bacterial isolates were identified and tested for antimicrobial susceptibility by VITEK 2; PVL was detected by PCR. RESULTS: In total, 1199 S. aureus isolates from 1074 patients with dSSTI were identified, and 613 (51.1%) of 1199 samples were PVL+. The median age of patients with PVL+S. aureus was lower than in patients with PVL- S. aureus (34 years, range 0-88 years, vs. 44 years, range 0-98 years; p < 0.0001). PVL was associated with repeated/multiple samples compared to single sample submission (69/92, 75% vs. 448/982, 45.6%, p < 0.0001; odds ratio (OR), 3.6; 95% confidence interval (CI), 2.2-5.8). Interestingly, the highest PVL positivity rate was found in isolates from gluteal (82/108, 75.9%; OR, 3.6; 95% CI, 2-5) or axillary (76/123, 61.8%; OR, 2; 95% CI, 1.1-3.3) localizations compared to isolates from the arm. The PVL positivity rate did not increase over time. Yet we noticed an increase in the trimethoprim/sulfamethoxazole (SXT) resistance rate in PVL+ isolates, mainly methicillin-sensitive S. aureus, when considering SXT resistance rates of 2007-2012 versus 2013-2017 (35/226, 15.5% vs. 74/289, 25.6%; p 0.01). CONCLUSIONS: In outpatients, gluteal and axillary dSSTI are indicative of PVL+S. aureus. Providing SXT as a complementary treatment for dSSTI should be based on susceptibility testing.


Asunto(s)
Toxinas Bacterianas/metabolismo , Exotoxinas/metabolismo , Leucocidinas/metabolismo , Infecciones de los Tejidos Blandos/patología , Infecciones Cutáneas Estafilocócicas/patología , Staphylococcus aureus/metabolismo , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antibacterianos/uso terapéutico , Proteínas Bacterianas/metabolismo , Niño , Preescolar , Humanos , Lactante , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Proteínas de Unión a las Penicilinas/metabolismo , Atención Primaria de Salud , Estudios Retrospectivos , Infecciones de los Tejidos Blandos/tratamiento farmacológico , Infecciones de los Tejidos Blandos/microbiología , Infecciones Cutáneas Estafilocócicas/tratamiento farmacológico , Infecciones Cutáneas Estafilocócicas/microbiología , Staphylococcus aureus/aislamiento & purificación , Combinación Trimetoprim y Sulfametoxazol/uso terapéutico , Adulto Joven
3.
MedEdPublish (2016) ; 9: 175, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-38073783

RESUMEN

This article was migrated. The article was marked as recommended. PROBLEM: Based on a specific community benefit analysis of Greenville, South Carolina, we identified the Dunean community with its increased prevalence of health inequities with respect to access to health care, poverty burden, and disease mortality on a county, state, and national level. The Dunean community's data reflect poorer health outcomes in terms of disease and unhealthy lifestyle as well as inadequate access to medical resources compared to other communities in South Carolina. APPROACH: Students, residents, attendings, faculty, and staff from the University of South Carolina School of Medicine Greenville (UofSC SOMG) formed a task force to engage the community and combat the root causes of diseases. This task force built partnerships with community leaders to create Root Cause, a monthly health event designed to bring community members to a unified space, share a free community dinner, and provide a wide range of health and wellness resources to educate and inspire them to make healthy lifestyle choices. Outcomes: This report describes the formation of the community engagement task force and execution of Root Cause. In five Root Cause events, we partnered with 36 community agencies and our academic health center partners who shared their resources, served 207 Dunean neighborhood members, and facilitated 1,237 total interactions between community members and partners. CONCLUSION: Under the Root Cause model, medical students and neighborhood partners have initiated a trusted, bidirectional dialogue to determine their specific needs with the desire to positively transform the health and wellness of the Dunean community. Our data suggests that based on our efforts, the neighborhood of Dunean, SC increased community cohesiveness and improved perceptions of access to health care. Additionally, participating medical students advanced their understanding of social health and economic challenges which helped to facilitate their development along the active citizen continuum, as well as increase empathy for their future patients in the local community.

4.
Br J Cancer ; 108(2): 265-70, 2013 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-23329236

RESUMEN

BACKGROUND: This study was designed to compare cisplatin/docetaxel with oxaliplatin/docetaxel in patients with advanced and metastatic non-small lung cancer as a first-line treatment. METHODS: Patients were randomly assigned to receive either cisplatin 75 mg m(-2) and docetaxel 75 mg m(-2) every 3 weeks or oxaliplatin 85 mg m(-2) and docetaxel 50 mg m(-2) every 2 weeks. The primary end point was response rate, and secondary end points were toxicity, time to progression and overall survival. RESULTS: A total of 88 patients (median age: 65 (39-86) years; stage IV: 93%) were randomly assigned. Response rate (complete and partial response) was 47% (95% CI: 33-61%) in the cisplatin/docetaxel arm and 28% (95% CI: 17-43%) in the oxaliplatin/docetaxel arm (P=0.118). There was no significant difference in time to progression (6.3 vs 4.9 months, P=0.111) and median overall survival (11.6 vs 7.0 months, P=0.102) with cisplatin/docetaxel vs oxaliplatin/docetaxel, although slight trends favouring cisplatin were seen. Oxaliplatin/docetaxel was associated with significantly less (any grade) renal toxicity (56% vs 11%), any grade fatigue (81% vs 59%), complete alopecia (76% vs 27%), any grade leukopenia (84% vs 61%) and grade 3/4 leukopenia (44% vs 14%) and neutropenia (56% vs 27%). CONCLUSION: Oxaliplatin/docetaxel has activity in metastatic non-small cell lung cancer, but it seems to be inferior to cisplatin/docetaxel.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Cisplatino/administración & dosificación , Neoplasias Pulmonares/tratamiento farmacológico , Compuestos Organoplatinos/administración & dosificación , Taxoides/administración & dosificación , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Monoclonales Humanizados/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Bevacizumab , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Cisplatino/efectos adversos , Docetaxel , Esquema de Medicación , Femenino , Humanos , Neoplasias Pulmonares/mortalidad , Masculino , Persona de Mediana Edad , Compuestos Organoplatinos/efectos adversos , Oxaliplatino , Taxoides/efectos adversos , Resultado del Tratamiento
5.
J Clin Microbiol ; 47(9): 2912-7, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19571014

RESUMEN

The clinical impact of severe infections with yeasts and yeast-like fungi has increased, especially in immunocompromised hosts. In recent years, new antifungal agents with different and partially species-specific activity patterns have become available. Therefore, rapid and reliable species identification is essential for antifungal treatment; however, conventional biochemical methods are time-consuming and require considerable expertise. We evaluated matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the rapid routine identification of clinical yeast isolates. A total of 18 type collection strains and 267 recent clinical isolates of Candida (n = 250), Cryptococcus, Saccharomyces, Trichosporon, Geotrichum, Pichia, and Blastoschizomyces spp. were identified by MALDI-TOF MS. The results were compared with those obtained by conventional phenotyping and biochemical tests, including the API ID 32C system (bioMérieux, Nürtingen, Germany). Starting with cells from single colonies, accurate species identification by MALDI-TOF MS was achieved for 247 of the clinical isolates (92.5%). The remaining 20 isolates required complementation of the reference database with spectra for the appropriate reference strains which were obtained from type culture collections or identified by 26S rRNA gene sequencing. The absence of a suitable reference strain from the MALDI-TOF MS database was clearly indicated by log(score) values too low for the respective clinical isolates; i.e., no false-positive identifications occurred. After complementation of the database, all isolates were unambiguously identified. The established API ID 32C biochemical diagnostic system identified 244 isolates in the first round. Overall, MALDI-TOF MS proved a most rapid and reliable tool for the identification of yeasts and yeast-like fungi, with the method providing a combination of the lowest expenditure of consumables, easy interpretation of results, and a fast turnaround time.


Asunto(s)
Técnicas de Laboratorio Clínico/métodos , Micosis/diagnóstico , Micosis/microbiología , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Levaduras/clasificación , Levaduras/aislamiento & purificación , Análisis por Conglomerados , Alemania , Humanos , Sensibilidad y Especificidad , Levaduras/química
6.
Torture ; 19(3): 238-47, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-20065542

RESUMEN

UNLABELLED: The substantial impact of the war in Kosovo has been documented by earlier research performed shortly after the war, but only limited data on the long term mental health impact have been published so far, mostly limited to posttraumatic stress (PTSD). The present study is aimed at extending the focus to a major question so far neglected in most post-conflict zones, namely that of depression and suicidal ideation. METHODS: The present study was based on a representative country-wide survey (n=1161) , using subscales for suicidal behaviour in the General Health Questionnaire (GHQ), comparing results with the corresponding Hopkins Symptom Checklist (HSCL-25) items and the Harvard Trauma Questionnaire (HTQ) to assess war related experiences and PTSD symptomatology. Irrespective of age, gender or education, subjects in rural areas had higher suicide ideation scores, 41.7% of respondents met criteria for moderate to severe depressive symptomatology, 41.6% for clinical anxiety. Unemployment (83.7%), and high PTSD scores were associated with suicidal ideation scores, the last contingent on depressive mood. It is concluded, that suicidal ideation linked to both past stressful experience and present social stressors is a question to be considered in mental health care plans in post-conflict zones. Under-recognition could be expected to result in increasing suicidal behaviour. Ideation also indicates, especially in the context of high post-traumatic stress and depression rates, exhaustion and despair that need to be addressed by more general interventions than individual Psychotherapeutic treatment.


Asunto(s)
Trastornos por Estrés Postraumático/psicología , Suicidio/psicología , Adolescente , Adulto , Factores de Edad , Anciano , Ansiedad/epidemiología , Ansiedad/psicología , Estudios Transversales , Depresión/epidemiología , Depresión/psicología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica , Refugiados/psicología , Factores Sexuales , Trastornos por Estrés Postraumático/epidemiología , Suicidio/estadística & datos numéricos , Factores de Tiempo , Guerra , Adulto Joven , Yugoslavia/epidemiología
7.
Nucleosides Nucleotides Nucleic Acids ; 22(5-8): 1579-81, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-14565470

RESUMEN

A photocleavable o-nitrobenzyl CE phosphoramidite building-block was synthesised and incorporated within oligonucleotides. After allele-specific primer extension, desalting was performed using genostrep purification plates. Release of the SNP information containing part through photocleavage created shortened molecules that are easily accessible for MALDI-TOF analysis. Additionally, incorporation of mass modified nucleosides enables flexible design of multiplex genotyping.


Asunto(s)
Oligonucleótidos/química , Polimorfismo de Nucleótido Simple/genética , Factor V/genética , Genotipo , Humanos , Fotólisis , Protrombina/genética , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos
8.
Micron ; 34(2): 85-96, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12801541

RESUMEN

Superconducting MgB(2) ceramics were prepared and yield superconducting transition temperatures of about 39 K. For covering the various length scales on which inhomogeneities appear in MgB(2), electron-probe micro-analysis (EPMA) and analytical transmission electron microscopy (TEM) were applied for a phase analysis. Particularly useful were the preliminary electron spectroscopic imaging (ESI) results in the TEM. It could be shown by EPMA that the microstructure consists of a Mg-B-O matrix and boron-rich secondary phases of composition close to MgB(12). It was unclear in which form oxygen was present in the superconducting matrix. By combining the acquisition of B-K and O-K edge jump ratio images and energy-dispersive X-ray spectroscopy in the TEM, we could prove that the matrix consists of superconducting MgB(2) and MgO. Most of the MgO precipitates and grains appear with diameters between 20 and 300 nm. The size distribution of MgO was inhomogeneous and oxygen-rich areas of dimensions >1 microm were also observed. Edge jump ratio images obtained by ESI were analysed for determining the signal values and effects of multiple inelastic scattering.


Asunto(s)
Compuestos de Boro/química , Cerámica/química , Microanálisis por Sonda Electrónica , Compuestos de Magnesio/química , Microscopía Electrónica , Cristalización , Conductividad Eléctrica , Oxígeno/metabolismo
9.
Depress Anxiety ; 16(3): 100-3, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12415533

RESUMEN

Past clinical research has identified depression as the most common psychiatric disorder associated with cervical dystonia (CD). The purpose of our study is to document different patterns of psychopathology, the frequency of psychiatric disorders, and possible correlation with the neurological disorder in patients with CD. Forty patients with CD were investigated to assess levels of psychopathology on two self-rated scales: the Beck Depression Inventory (BDI) and Symptom Check List (SCL-90). To determine the presence of psychiatric disorders, the patients were evaluated using the standard instrument in the DSM-III-R (Structured Clinical Interview Schedule, SCID). A small group of dystonic patients (12%) had higher levels of psychopathology, with significant amounts of concomitant anxiety and depression on the BDI and SCL-90. SCID criteria for at least one psychiatric disorder were fulfilled in 22 patients (55%), including both the lifetime and current diagnoses. The most frequent diagnostic categories were anxiety (40%) and major depressive disorders (37.5%). In 17 patients (42.5%), criteria for at least one lifetime diagnosis were fulfilled prior to the onset of CD. Psychiatric evaluation does not indicate one specific disorder associated with CD. The presence of anxiety and depression symptoms before and during the course of dystonia, without a possible causal relationship, could mean that the alteration of a chain of physiological events in the central nervous system may not lead to a single clinical picture. The relatively high overall lifetime prevalence of anxiety and depressive disorders may indicate the need for a broader diagnostic and therapeutic approach to patients with focal dystonia.


Asunto(s)
Trastornos de Ansiedad/epidemiología , Toxinas Botulínicas Tipo A/uso terapéutico , Trastorno Depresivo Mayor/epidemiología , Fármacos Neuromusculares/uso terapéutico , Tortícolis/tratamiento farmacológico , Tortícolis/epidemiología , Adulto , Edad de Inicio , Trastornos de Ansiedad/diagnóstico , Trastornos de Ansiedad/psicología , Comorbilidad , Trastorno Depresivo Mayor/diagnóstico , Trastorno Depresivo Mayor/psicología , Femenino , Humanos , Masculino , Estudios Retrospectivos , Índice de Severidad de la Enfermedad
10.
Anal Chem ; 73(17): 501A-502A, 2001 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-11569847
11.
Artículo en Inglés | MEDLINE | ID: mdl-11563035

RESUMEN

The synthesis of phosphoramidites containing 7-deazaguanine, 7-deazaadenine, uracil and cytosine carrying aminopropargyl chains is described. The corresponding oligonucleotides are stabilized in duplexes thermally as well as against degradation by exonucleases.


Asunto(s)
Oligonucleótidos/síntesis química , Compuestos Organofosforados/síntesis química , Purinas/química , Pirimidinas/química
12.
Artículo en Inglés | MEDLINE | ID: mdl-11563137

RESUMEN

The synthesis of positively charged and mass tagged nucleosides containing a quaternary ammonium functionality within the penultimate position of a primer is described. Neutralization of the sugar/thiophosphate backbone by alkylation increases the detection sensitivity in the mass spectrometric analysis by a factor of at least 100. The variable introduction of these novel compounds within the extension primers enables flexible design of multiplex genotyping reactions.


Asunto(s)
Nucleósidos/síntesis química , Pargilina/análogos & derivados , Pargilina/química , Polimorfismo de Nucleótido Simple , Propilaminas/química , ADN/química , ADN/genética , Genotipo , Humanos , Nucleósidos/química , Compuestos Organofosforados/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos
14.
Anal Chem ; 73(1): 43A-44A, 2001 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-11195510
15.
Psychopathology ; 34(6): 289-98, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11847488

RESUMEN

Although nearly a century has passed since Kraepelin's investigations in Java [Cbl Nervenheilk Psychiatr 1904; 27:468-469], one crucial question regarding guilt in the course of depression has still not been decided: Is there a more or less stable connection independent of culture, or is guilt confined to certain civilisations? This study investigated this issue in 100 Pakistani and 100 Austrian out-patients diagnosed with 'major depression' according to DSM-IV by means of standardised instruments (Schedule for Affective Disorders and Schizophrenia-Life Time Version, Hamilton Rating Scale for Depression, 21-item version). The experiences of guilt were subdivided into ethical feelings (ethical anxiety and feelings of guilt) and delusions of guilt. It turned out that ethical feelings could be found in both cultures regardless of age and sex. They seem to be primarily related to the extent of depressive retardation. However, the distribution of the two subsets of ethical feelings was culture dependent. Delusions of guilt were confined to patients of the Austrian sample. So, our data qualify the exclusivity of the aforementioned two points of view and support the need for a psychopathologically differentiated approach.


Asunto(s)
Comparación Transcultural , Trastorno Depresivo Mayor/etnología , Países en Desarrollo , Culpa , Adulto , Anciano , Austria , Cristianismo , Trastorno Depresivo Mayor/diagnóstico , Trastorno Depresivo Mayor/psicología , Femenino , Humanos , Islamismo , Masculino , Persona de Mediana Edad , Pakistán , Religión y Psicología , Valores Sociales
16.
Enantiomer ; 5(3-4): 293-302, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11126870

RESUMEN

Achiral lanthanide tris beta-diketonate complexes are added to the acid and ester derivatives of the chiral NMR solvating agents dinitrobenzoyl-L-leucine and N-1-(1-naphthyl)ethylaminocarbonyl-L-valine to enhance enantiomeric discrimination. With the acid derivative, the solvating agent bonds directly to the lanthanide(III) complex to create an anionic species, and larger shifts are usually observed for the resonances of the enantiomer that associates more strongly with the solvating agent. With the ester derivative, the solvating agent generally does not bind to the lanthanide, whereas the substrate does. In this situation, the enantiomer that associates less strongly with the solvating agent exhibits the larger lanthanide-induced shifts. The effectiveness of adding neutral lanthanide complexes containing two beta-diketonate ligands and one chiral carboxylate ligand is compared to the anionic species with three beta-diketonate ligands and a chiral carboxylate ligand.

17.
Psychopathology ; 33(6): 292-6, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11060511

RESUMEN

Post-traumatic stress disorder (PTSD) has been described as the characteristic sequel to extreme events in life such as war and especially torture. This limitation to a single approach in regard to diagnosis and treatment has been criticised as being a too narrow concept to describe the effects following extreme events in life, especially as most studies so far were limited to PTSD and a small range of symptoms or disorders. The study presents data on psychiatric disorders in a group of exiled survivors of torture presenting to an out-patient department for psychiatry. A DSM-III-R-based psychiatric interview, including the general assessment of functioning scale (GAF), an open list of symptoms and the Vienna diagnostic criteria in regard to depression were used to evaluate a broader range of possible sequels. The most frequent present diagnosis in 44 patients seen over a period of 3 years was PTSD (n = 40), but criteria for a present diagnosis of other disorders were fulfilled in 34 patients, even years after torture, mainly major depression or dysthymia (n = 26). Criteria for functional psychosis were fulfilled in 4 patients. Many patients reported symptoms not assessed by DSM-III-R criteria, including feelings of shame and guilt, and ruminations on existential fears. The impairment as indicated by the GAF (mean 59.1) correlated best with the presence of the endogenomorphic-depressive axial syndrome, but not with duration of imprisonment, age or other factors. Research on sequels to extreme trauma should not be restricted to a simple diagnosis of PTSD, but should continue to look for a broader conceptualisation, including neglected categories like the axial syndrome, as PTSD is common, but might not be the only factor of importance for research and treatment. ICD-10 might offer a more adequate interpretation of sequels.


Asunto(s)
Trastorno Distímico/etiología , Trastornos por Estrés Postraumático/etiología , Sobrevivientes/psicología , Tortura/psicología , Adulto , Trastorno Distímico/diagnóstico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Trastornos por Estrés Postraumático/diagnóstico
18.
J Psychosom Res ; 48(6): 589-91, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11033379

RESUMEN

OBJECTIVE: The purpose of this study was to assess the life-time prevalence of all major psychiatric disorders in patients suffering from blepharospasm. METHOD: A total of 31 consecutive patients with blepharospasm attending the Department of Neurology were interviewed at the Department of Psychiatry at the University of Vienna. Patients had been submitted to standard neurological diagnostic procedures, psychiatric diagnoses were made with the help of the SCID, functional impairment was assessed by the General Assessment of Functioning Scale (GAF). RESULTS: A current or life-time psychiatric diagnosis was made for 22 patients (71%). The most frequent disorders were depressive disorders, mainly major depression (five patients, 16.1%), secondary dysthymia (six patients, 19.3%), and recurrent major depression (five patients, 16.1%). A diagnosis of simple phobia was made for seven patients (22.5%), for obsessive-compulsive disorder in three patients (9.6%). The mean GAF score of our sample was 63.1%. CONCLUSION: In contrast to previously published results, we did not find a high rate of a single specific disorder or patterns in our study sample, though by the inclusion of life-time diagnostic criteria, the majority of patients fulfilled criteria for at least one diagnosis. This might indicate the considerable negative impact of blepharospasm on the patients' lives.


Asunto(s)
Blefaroespasmo/psicología , Trastornos Mentales/diagnóstico , Trastornos Psicofisiológicos/diagnóstico , Anciano , Trastorno Depresivo/diagnóstico , Trastorno Depresivo/psicología , Femenino , Humanos , Masculino , Trastornos Mentales/psicología , Persona de Mediana Edad , Determinación de la Personalidad , Trastornos Psicofisiológicos/psicología
19.
Phys Rev Lett ; 84(24): 5644-7, 2000 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-10991015

RESUMEN

We describe a new technique to determine the homogeneous linewidths of surface plasmon resonances of metal nanoparticles and thus measure the decay time of this collective electron excitation. The method is based on spectral hole burning and has been applied to supported oblate Ag particles with radii of 7.5 nm. From the experimental results and a theoretical model of hole burning the linewidth of 260 meV corresponding to a decay time of 4.8 fs was extracted. This value is shorter than expected for damping by bulk electron scattering. We conclude that additional damping mechanisms have been observed and reflect confinement of the electrons in nanoparticles with sizes below 10 nm.

20.
Lancet ; 355(9214): 1550, 2000 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-10801191
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