Unveiling the Atomic and Electronic Structure of Stacked-Cup Carbon Nanofibers.

We report results of comprehensive experimental exploration (X-ray photoemission, Raman and optical spectroscopy) of carbon nanofibers (CNFs) in combination with first-principles modeling. Core-level spectra demonstrate prevalence of sp2 hybridization of carbon atoms in CNF with a trace amount of carbon-oxygen bonds. The density functional theory (DFT)-based calculations demonstrated no visible difference between mono- and bilayers because σ-orbitals are related to in-plane covalent bonds. The influence of the distortions on π-peak is found to be significant only for bilayers as a result of π-π interlayer bonds formation. These results are supported by both experimental Raman and XPS valence band spectra. The combination of optical measurements with a theoretical modeling indicates the formation of optically active graphene quantum dots (GQDs) in the CNF matrix, with a radiative relaxation of the excited π* state. The calculated electronic structure of these GQDs is in quantitative agreement with the measured optical transitions and provides an explanation of the absence of visible contribution from these GQDs to the measured valence bands spectra.

Adecuación de las derivaciones desde atención primaria al servicio de urgencias hospitalario en el Área 9 de Madrid / Adequacy of primary health care to outpatient emergency clinic refarrals in Area 9 in Madrid

Objetivo: Conocer la adecuación de las derivaciones desde atención primaria (AP) al servicio de urgencias hospitalario en el Área 9 de Madrid. Objetivos secundarios: - Descripción de las patologías derivadas. - Grado de información clínica presente en los volantes de derivación. Métodos: Diseño: Estudio descriptivo transversal. Participantes: Pacientes atendidos en el Hospital Severo Ochoa (Leganés), remitidos con volante de derivación por médicos de AP, entre el 1 de marzo y el 10 de abril del 2003. Mediciones: Se recogieron variables sociodemográficas (edad, género), variables sobre temporalidad (día de la semana, hora de llegada), variables sobre información en los volantes de derivación (motivo de la misma, historia clínica, exploración física, juicio clínico), variables sobre la atención en urgencias (descripción de la patología, requerimiento de pruebas diagnósticas, pertinencia de la derivación). Resultados: Se consideraron adecuadas el 49,4% de las derivaciones. El grupo de edad de 0-30 años fue el más derivado y el viernes el día más frecuentado. El 64% fue dado de alta en menos de 3 horas. Ingresó el 2,7%. Los mejor derivados fueron los mayores de 65 años y en turno de noche. En los volantes constaba el juicio clínico solo en el 60,7% y el motivo de derivación más frecuente fue la demanda de valoración (89,2%). Conclusiones: La mitad de las derivaciones fueron adecuadas. Los pacientes de mayor edad y con patologías potencialmente más graves son los mejor derivados. El volante de derivación es mejorable (AU)

Aim and purpose: To assess the adequacy of referrals from the Primary Health Care (PHC) environment to the hospital Outpatient Emergency Clinic in Area 9 in Madrid (Spain). Secondary aims: To describe the conditions referred. - Level of clinical information in the referral slips. Methods: Design: Cross-sectional descriptive study. Study population: Patients attended at the "Severo Ochoa" Hospital (Leganés, Madrid, Spain) who had been referred with a referral slip by PHC physicians between March 1st and April 10, 2003. Measurements: The recorded and assessed data included sociodemographic variables (age, gender), temporality variables (day of the week, hour of arrival), variables regarding the information in the referral slips (grounds for referral, clinical history, physical examination, clinical assessment), and variables regarding the Outpatient Emergency Clinic management (description of condition, requirements for diagnostic tests, pertinence of referral). Results: Forty-nine and four tenths per cent of the referrals were considered adequate. The 0-to-30-year age group was the most often referred one, and Friday the day with most referrals. Sixty-four per cent of the cases were discharged within 3 hours, and 2.7% were admitted into hospital. The most adequately referred cases were observed among patients over 65 years and during the night shift. Only 60.7% of the referral slips contained the clinical assessment, and the most frequent grounds for referral was "request for assessment" (89.2%). Conclusions: One-half of the referrals were adequate. Patients who were older and with potentially more severe conditions were those best referred. The referral slip might be improved (AU)

Moxonidina: un nuevo simpaticolítico de acción central

Moxonidina y rilmenidina representan a una familia de fármacos simpaticolíticos de reciente aparición con propiedades antihipertensivas que actúan estimulando los receptores imidazolínicos I-1 localizados en el bulbo. La eficacia antihipertensiva de estos fármacos ha sido confirmada en estudios clínicos y experimentales con efectos favorables sobre la hipertrofia ventricular izquierda y la distensibilidad arterial. El efecto adverso más significativo es la bradicardia, por lo que debe evitarse en pacientes con menos de 50 latidos/minuto. Se puede combinar con otros fármacos excepto con aquellos que inducen bradicardia (AU)

[New concepts on atrial fibrillation]. / Nuevos conceptos sobre la fibrilación auricular.

Atrial Fibrillation (AF) is the most common sustained arrhythmia in humans. AF has a self-perpetuating nature. Perpetuation has been attributed to shortening of atrial action potential duration (APD) and APD adaptation to rate, the so called atrial electrical remodeling. There is evidence that alterations in gene expression of proteins involved in the Ca handling may be, at least partly, responsible for AF-induced electrical remodeling. This review focus on the possible cellular mechanisms involved in atrial remodeling, followed by a brief description of new therapeutic approaches that target the development of the arrhythmogenic substrate, rather than simply attacking the final electrophysiologic environment.

Deficient interleukin-2 responsiveness of T lymphocytes from patients with primary biliary cirrhosis.

There is increasing evidence that primary biliary cirrhosis is associated with an alteration of the immune system. Although the cause remains unknown, it has been suggested that the immune system of patients with primary biliary cirrhosis is involved in the pathogenesis of their disease. We have investigated the T-cell function in patients with primary biliary cirrhosis and have found defective phytohemagglutinin-induced T-cell mitogenesis. Likewise, their blastogenic response to CD3 monoclonal antibody was also depressed, although the DNA synthesis induced by stimulation with phorbol esters (12-O-tetradecanoil-phorbol-13-acetate) plus ionophore (ionomycin) was normal. These alterations could not be ascribed either to a decreased synthesis of interleukin-2 or to a defective expression of interleukin-2 receptor after cellular activation. Moreover, this defective proliferative response of T lymphocytes was observed even in the presence of saturating concentrations of exogenous interleukin-2. These results represent evidence of the deficiency in the interleukin-2-dependent pathway found in T lymphocytes from patients with primary biliary cirrhosis.

Demineralized perforated bone implants in craniofacial surgery.

Between July 1990 and September 1991, demineralized perforated allogeneic bone implants (Pacific Coast Tissue Bank, Los Angeles, CA) were placed in 72 patients. Because many patients received more than one implant, a total of 248 implants were used in 80 procedures. The technology of processing demineralized bone implants is described in detail. All patients were operated on by one surgeon (K.E.S.) at the Humana Craniofacial Institute in Dallas, Texas. Forty-one patients had craniofacial deformities, 16 had secondary deformities following cleft lip and palate repair, 8 had bony defects following removal of tumors, and 10 had various skeletal deformities following trauma. Of the 72 patients, 6 had two surgical procedures during which additional implants were inserted. Implants placed in the cranial vault and the maxillary complex, including alveolar grafts, were inlay grafts, whereas implants placed in the orbital, nasal, paranasal, temporal, and malar areas were onlay grafts used for contouring, augmentation, or both. Complications were limited to delayed wound healing in 6 patients. According to our observations, demineralized perforated bone implants represent an encouraging alternative to autogenous bone grafting. Further clinical and experimental studies are necessary to obtain more information about this material.

Late relapse with nodular lymphoma after treatment for diffuse non-Hodgkin's lymphoma.

Histologic conversion from a low-grade non-Hodgkin's lymphoma (NHL) into a more aggressive histologic pattern is a common, well-documented event in NHL. The converse phenomenon, appearance of a low-grade, follicular NHL after treatment for diffuse, intermediate, or high-grade NHL, has only recently been recognized. The clinical, morphologic, and immunologic features of a patient in whom relapse with an indolent nodular lymphoma was noticed after combination chemotherapy for diffuse lymphoma are presented. Immunologic markers at presentation and relapse were similar. Other previously reported cases are reviewed. Implications for diagnosis and therapy as well as the pathogenesis of this unique form of conversion are discussed.

Natural killer activity in patients with breast cancer.

The clinical significance of the natural killer (NK) activity of peripheral blood mononuclear cells (PBMC) was analyzed in 83 breast cancer patients and 24 healthy control women. Similar levels of NK cytotoxic activity against K-562 target cells were found in PBMC from either untreated or surgically treated patients with local or disseminated breast cancer and from normal controls. However, a transitory and significant decrease (p less than 0.05) of the NK activity of PBMC from breast cancer patients was found during chemotherapy. But, according to quantitative flow cytometry analysis, similar percentages of phenotypically defined NK cells (CD16+, CD11b+, HNK-1+) were found in PBMC from patients, whether prior to or during chemotherapy, and healthy controls. Our results demonstrate that in breast cancer patients, the percentage of NK cells present in PBMC and their lytic activity are independent of the clinical and pathological stage of the disease.

Meningeal infiltration by non-myelomatous IgD-secreting plasma cell dyscrasias.

Two cases of meningeal invasion by non-myelomatous plasma cell dyscrasias--a plasma cell leukaemia and an extramedullary plasmacytoma--are described. Both were secretors of IgD paraprotein and both were diagnosed in life, characteristics which we have not found in any other published case of plasma cell leptomeningitis. Analysis of our patients and of another 25 cases suggests as predisposing factors of meningeal invasion the male sex, presentation in the form of plasma cell leukaemia, presence of the IgD paraprotein and tumoral involvement of pleura, lung, pericardium and testicles. Aggressive treatment of this neurological complication controlled the meningeal disorder in some cases. However, the majority died of disseminated disease in spite of systemic chemotherapy. Until an effective treatment can be found, able to maintain remission or cure the systemic disease, prophylaxis of the central nervous system in plasma cell dyscrasias does not appear to be advisable.