RESUMEN
In this Letter, a new approach to distinguish liquid water and ice based on dual spectrum neutron radiography is presented. The distinction is based on arising differences between the cross section of water and ice in the cold energy range. As a significant portion of the energy spectrum of the ICON beam line at Paul Scherrer Institut is in the thermal energy range, no differences can be observed with the entire beam. Introducing a polycrystalline neutron filter (beryllium) inside the beam, neutrons above its cutoff energy are filtered out and the cold energy region is emphasized. Finally, a contrast of about 1.6% is obtained with our imaging setup between liquid water and ice. Based on this measurement concept, the temporal evolution of the aggregate state of water can be investigated without any prior knowledge of its thickness. Using this technique, we could unambiguously prove the production of supercooled water inside fuel cells with a direct measurement method.
Asunto(s)
Congelación , Hielo , Difracción de Neutrones/métodos , Agua/química , Berilio/química , Difracción de Neutrones/instrumentaciónRESUMEN
A method combining (2)H labeling of different sources of H atoms (hydrogen, water vapor) with neutron imaging for the analysis of transport parameters in the bulk and at the interfaces of Nafion polymer electrolyte membranes is proposed. The use of different isotope compositions in the steady state allows evaluation of the relation between bulk and interface transport parameters, but relies on literature data for evaluating absolute values. By using transients of isotope composition, absolute values of these parameters including the self-diffusion coefficient of H can be extracted, making this method an attractive alternative to self-diffusion measurements using nuclear magnetic resonance (NMR), allowing measurements in precisely controlled conditions in real fuel cell structures. First measurements were realized on samples with and without electrodes and we report values of the self-diffusion coefficient of the same order of magnitude as values measured using NMR, although with slightly higher numbers. In our particular case, lower interfacial exchange rates for water transport were observed for samples with an electrode.
RESUMEN
BACKGROUND: Mycosis fungoides (MF) is the most frequent cutaneous T-cell lymphoma (CTCL). Arsenic trioxide (As(2)O(3)) has recently been shown to be effective against leukemias, so we studied whether As(2)O(3) induces apoptosis of CTCL cells in vitro. We further investigated if As(2)O(3) is effective in a MF mouse model. MATERIAL AND METHODS: Annexin V/7-amino-actinomycin-D stainings were carried out to investigate if As(2)O(3) induced apoptosis of CTCL cell lines. To study the underlying mechanisms, the effects of As(2)O(3) on various transcription factors and apoptosis regulating proteins were analyzed by western blots, electrophoretic mobility shift assays and transcription factor enzyme-linked immunosorbent assays. The ability of As(2)O(3) to induce tumor regression was investigated in a MF mouse model. RESULTS: As(2)O(3)-induced apoptosis was paralleled by a reduction of the DNA-binding activities of transcription factors of the NFkB and signal transducer and activator of transcription gene families and reduced expression of the antiapoptotic proteins bcl-1, bcl-xL and mcl-1. Local injections of 200 muM As(2)O(3) into tumors caused complete remissions in five of six mice and one partial remission. CONCLUSIONS: As(2)O(3) induced apoptosis of CTCL cells by the down-regulation of transcription factors that stimulate the expression of antiapoptotic genes. Local injection of As(2)O(3) into MF tumor-bearing mice resulted in tumor regression.
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Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Arsenicales/farmacología , Micosis Fungoide/tratamiento farmacológico , Óxidos/farmacología , Neoplasias Cutáneas/tratamiento farmacológico , Animales , Apoptosis/genética , Trióxido de Arsénico , Procesos de Crecimiento Celular/efectos de los fármacos , Línea Celular Tumoral , Regulación hacia Abajo/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Genes bcl-2/efectos de los fármacos , Humanos , Ratones , Ratones Desnudos , Micosis Fungoide/genética , Micosis Fungoide/patología , Proteína 1 de la Secuencia de Leucemia de Células Mieloides , FN-kappa B/biosíntesis , FN-kappa B/genética , FN-kappa B/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/biosíntesis , Proteínas Proto-Oncogénicas c-bcl-2/genética , Factor de Transcripción STAT5/biosíntesis , Factor de Transcripción STAT5/genética , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Linfocitos T/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto , Proteína X Asociada a bcl-2/biosíntesis , Proteína X Asociada a bcl-2/genética , Proteína bcl-X/biosíntesis , Proteína bcl-X/genéticaRESUMEN
PURPOSE: To relate different types of radiographic contrast material distributions to anatomic compartments by using cadaveric specimens and to relate the injection site to treatment-induced discomfort and therapeutic effect. MATERIALS AND METHODS: The contrast material distributions of selective nerve root blocks (SNRBs) in 36 patients (13 women, 23 men; mean age, 52 years; age range, 22-88 years) were graded by two radiologists in conference as type 1 (tubular appearance), type 2 (nerve root visible as filling defect), or type 3 (nerve root not visible). These patterns were correlated with pain reduction after 15 minutes and 2 weeks (with a visual analogue scale of 100-mm length). In addition, 30 nerve roots were injected with iodine-containing contrast material and blue dye in three cadaveric specimens. Radiographs were compared with anatomic sections. RESULTS: After 15 minutes and 2 weeks, 75% and 86% of the patients, respectively, reported pain relief. Mean pain relief length after 15 minutes for type 1 distribution was 60 mm; for type 2, 44 mm; and for type 3, 22 mm; and after 2 weeks, it was 34 mm for type 1, 31 mm for type 2, and 57 mm for type 3. There was no correlation between early and late response. Pain during intervention was less pronounced in type 2 injection, compared with type 1 (P = .002). On the basis of anatomic sections, type 1 injection was intraepineural; type 2, extraepineural; and type 3, paraneural. CONCLUSION: Therapeutic SNRB is effective in sciatica, but early response does not predict the effect after 2 weeks. Type 1 injections are more painful than type 2 injections.
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Medios de Contraste/administración & dosificación , Bloqueo Nervioso , Ciática/terapia , Raíces Nerviosas Espinales , Adulto , Anciano , Anciano de 80 o más Años , Amidas/administración & dosificación , Anestésicos Locales/administración & dosificación , Antiinflamatorios/administración & dosificación , Femenino , Humanos , Técnicas In Vitro , Inyecciones/métodos , Yopamidol/administración & dosificación , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Radiografía , Ropivacaína , Ciática/diagnóstico por imagen , Raíces Nerviosas Espinales/diagnóstico por imagen , Triamcinolona Acetonida/administración & dosificaciónRESUMEN
BACKGROUND: The fate of patients suffering from laryngeal carcinoma is influenced strongly by the stage of the tumor at the time of diagnosis. This factor is also critical for preservation of the organ. It may be impossible to diagnose the tumor with the first biopsy even though the clinical and macroscopic aspect suggests a malignancy. METHODS: In a retrospective study, we examined 468 patients with laryngeal carcinoma who were treated at the departments of otorhinolaryngology at the University of Basel (B) (198 patients from 1983-1992) or in Giessen (G) (270 from 1990-1995). The number of biopsies necessary to confirm the diagnosis was analysed and the follow-up of the patients was evaluated. Thirty of 32 negative histologic samples were reexamined. RESULTS: Of 468 patients, 32 (7%, 27 [B] 14%; and 5 [C] 2%) required two to six biopsies to confirm the clinically suspected diagnosis: Twenty patients (designated as Group 1) were diagnosed within one to three months, and no patient showed a change of tumor stage within that time. Their first biopsies have to be considered as "nonrepresentative". Eight patients (Group 2) were diagnosed within four to 24 months and four patients (Group 3) more than 24 months after the first biopsy. Final treatment and outcome in patients from Group 1 was unchanged by the time delay in diagnosing the tumor. Seven of eight patients in Group 2 experienced an obvious progression of their tumor during the diagnostic period, which led to laryngectomy in several cases. In four patients, diagnosis was confirmed more than two years after the first biopsy. These were special cases such as development of cancer out of a papillomatosis or chronic laryngitis. CONCLUSIONS: A time delay of three months in diagnosing cancer of the larynx does not have a significant influence on organ preservation and prognosis, even though especially in small tumors suspicion of cancer should lead to a new representative biopsy as fast as possible to preserve the larynx.