Characterisation of neutron spectra in mixed high energy fields in lineal accelerators: response functions validation

Actualment, la resposta de la majoria d���instrumentaci�� operacional i dels dos��metres personals utilitzats en radioprotecci�� per a la dosimetria neutr��nica ��s altament dependent de l���energia dels espectres neutr��nics a analitzar, especialment amb camps neutr��nics amb una important component intermitja. En conseq����ncia, la interpretaci�� de les lectures d���aquests aparells es complicada si no es t�� un coneixement previ de la distribuci�� espectral de la flu��ncia neutr��nica en els punts d���inter��s. El Grup de F��sica de les Radiacions de la Universitat Aut��noma de Barcelona (GFR-UAB) ha desenvolupat en els ��ltims anys un espectr��metre de neutrons basat en un Sistema d���Esferes Bonner (BSS) amb un contador proporcional d���3He com a detector actiu. Els principals avantatges dels espectr��metres de neutrons per BSS s��n: la seva resposta isotr��pica, la possibilitat de discriminar la component neutr��nica de la gamma en camps mixtos, i la seva alta sensibilitat neutr��nica als nivells de dosi analitzats. Amb aquestes caracter��stiques, els espectr��metres neutr��nics per BSS compleixen amb els est��ndards de les ��ltimes recomanacions de la ICRP i poden ser utilitzats tamb�� en el camp de la dosimetria neutr��nica per a la mesura de dosis en el rang d���energia que va dels t��rmics fins als 20 MeV, en nou ordres de magnitud. En el marc de la col���laboraci�� entre el GFR - UAB i el Laboratorio Nazionale di Frascati ��� Istituto Nazionale di Fisica Nucleare (LNF-INFN), ha tingut lloc una experi��ncia comparativa d���espectrometria per BSS amb els feixos quasi monoenerg��tics de 2.5 MeV i 14 MeV del Fast Neutron Generator de l���ENEA. En l���exercici s���ha determinat l���espectre neutr��nic a diferents dist��ncies del blanc de l���accelerador, aprofitant el codi FRUIT recentment desenvolupat pel grup LNF. Els resultats obtinguts mostren una bona coher��ncia entre els dos espectr��metres i les dades mesurades i simulades.

Estudi comparatiu de la gesti�� de mem��ria de dues m��quines virtuals

En aquest projecte s'han comparat els gestors de mem��ria de les m��quines virtuals de Java i del projecte Mono.

Publicaci��n de un proyecto de Software Libre

Proceso a seguir para la publicaci��n de un proyecto de Software Libre y la creaci��n de una comunidad que lo contin��e.

Utilidad de la densitometr��a de doble energ��a (DEXA) en la valoraci��n de las alteraciones morfol��gicas y estructurales en el paciente VIH en relaci��n con distintos reg��menes de tratamiento antiretroviral (TAR)

Objetivo: Comparar la distribuci��n de la grasa corporal mediante DEXA, en pacientes VIH+ monoinfectados y coinfectados VHC, que reciben tratamiento antirretroviral basado en inhibidores de proteasa o no nucl��osidos. Materiales y M��todos: Estudio retrospectivo, observacional, unic��ntrico. Resultados: 80 pacientes, 60 hombres, 20 mujeres. 41 monoinfectados, 39 coinfectados. Edad 48 a��os, peso 71 kg, IMC 24, 39 IP, 41 NN. Los coinfectados ten��an triglic��ridos, colesterol y LDL-c inferiores a los monoinfectados (p <0.05). La DEXA no mostr�� diferencias en la comparaci��n de mono/coinfectados y grupos de tratamiento. Conclusiones: No se encontraron diferencias entre grupos. Los coinfectados muestran l��pidos plasm��ticos inferiores.

Electron localization function at the correlated level

The electron localization function (ELF) has been proven so far a valuable tool to determine the location of electron pairs. Because of that, the ELF has been widely used to understand the nature of the chemical bonding and to discuss the mechanism of chemical reactions. Up to now, most applications of the ELF have been performed with monodeterminantal methods and only few attempts to calculate this function for correlated wave functions have been carried out. Here, a formulation of ELF valid for mono- and multiconfigurational wave functions is given and compared with previous recently reported approaches. The method described does not require the use of the homogeneous electron gas to define the ELF, at variance with the ELF definition given by Becke. The effect of the electron correlation in the ELF, introduced by means of configuration interaction with singles and doubles calculations, is discussed in the light of the results derived from a set of atomic and molecular systems

Experiencia con Telaprevir en una corte de pacientes monoinfectados y coinfectados en un hospital de tercer nivel

Objetivos: avaluar tasas de respuestas y seguridad, a las 24 semanas del inicio de tratamiento, en pacientes monoinfectados por VHC y coinfectados VIH/VHC con Telaprevir. M��todos: estudio descriptivo transversal de los pacientes mono y coinfectados (tanto ���naive���, recaedores, no respondedores y respondedores parciales), tratados con Telaprevir en una Unidad de Enfermedades Infecciosas. Se recogieron los datos demogr��ficos de cada paciente, datos anal��ticos, inmunol��gicos y virol��gicos as�� como la determinaci��n de polimorfismo IL B28. Se recogen datos basales y a las 4, 8, 12 y 24 semanas. Resultados: un total de 43 pacientes analizados que iniciaron tratamiento con Telaprevir. Completan tratamiento hasta 12 semanas los 43, y hasta la semana 24 con Peginterferon y Rivabirina un total de 35 pacientes. Un 48% eran pacientes monoinfectados y un 51% coinfectados VIH-VHC. Un 80% eran hombres y un 20% mujeres, con una edad media de 52 a��os +/- 8��79. A las 12 semanas, un 76% de los pacientes monoinfectados y un 86% de los coinfectados ten��an indetectable VHC, y a las 24 semanas un 86% de los monoinfectados y un 90% de los coinfectados, manten��an respuesta viral en tratamiento, sin ser estas diferencias estad��sticamente significativas. De la misma forma no se encontraron diferencias estad��sticamente significativas en las proporciones de efectos secundarios. Conclusiones: la efectividad y la seguridad del tratamiento con triple terapia que incluye Teleprevir en la infecci��n cr��nica de VHC, son similares en pacientes monoinfectados y coinfectados.

S��ntesi i optimitzaci�� de la DPTMephos. Complexos de Mo i W

La ruta sint��tica del bis(2-((difenilfosfino)metil)fenil)sulf��, Ph2PCH2-(C6H4)S(C6H4)-CH2PPh2 , DPTMephos, involucra 5 reaccions en 4 etapes ben diferenciades. Es per aquest motiu que es fa necess��ria una optimitzaci�� de la ruta sint��tica per assolir rendiments m��s elevats. La primera reacci�� parteix del sulfur de difenil i involucra la formaci�� d���un complex litiat per acabar realitzant una carbonilaci�� amb N,N-DMF per obtindre un dialdehid. El seg��ent pas de la ruta passa per la reducci�� del producte al diol corresponent. Tot seguit ja es por preparar el substrat mitjanjant una bromaci�� per a que en l�����ltima etapa, s���acobli a l���estructura el grup difenilfosfino. Tant mateix s���han sintetitzat els is��mers de la DPTMephos amb [W(CO)6] i [Mo(CO)6], observant-se la formaci�� tant dels complexos meridionals com facials i la seva interconversi��. Tot seguit s���ha desenvolupat la sulfuraci�� de la DPTMephos per obtindre els lligands tant mono com di sulfurats. Tamb�� s���ha realitzat un estudi de l���espectre de RMN 31P{1H} del complex fac-[Mo(CO)3(DPTMephos)] a temperatura variable per determinar el senyal de cada f��sfor no equivalent a 200K. S���ha realitzat un estudi de forma qualitativa de les conformacions que adopta l���anell quelat de 6 baules en les conformacions tant meridional com facial d���un complex.

Synovial fluid examination for the diagnosis of synovial amyloidosis in patients with chronic renal failure undergoing haemodialysis

The diagnosis of synovial amyloidosis is based upon synovial biopsy. Synovial fluid (SF) in seven patients with amyloid arthropathy associated with chronic renal failure undergoing haemodialysis were studied. The SF and synovial samples of 10 consecutive patients with seronegative mono- or oligoarthritis served as controls. Six of the seven patients with amyloid positive synovial biopsy specimens showed amyloid in their SF. No amyloid was found in the synovial tissue or fluid of the 10 patients in the control group, the sensitivity being 87.7%. The finding of amyloid in SF was highly reproducible, showing its presence in the same joint on several occasions. The deposits were Congophilia resistant to potassium permanganate pretreatment, and the immunohistochemical analysis proved that they contained beta 2 microglobulin. The high sensitivity and good reproducibility of the method shows that the finding of amyloid in SF is sufficient for the diagnosis of synovial amyloidosis. It is possible to perform immunohis

Gas collisions and pressure quenching of the photoluminescence of silicon nanopowder grown by plasma-enhanced chemical vapor deposition

The quenching of the photoluminescence of Si nanopowder grown by plasma-enhanced chemical vapor deposition due to pressure was measured for various gases ( H2, O2, N2, He, Ne, Ar, and Kr) and at different temperatures. The characteristic pressure, P0, of the general dependence I(P) = I0��exp(��P/P0) is gas and temperature dependent. However, when the number of gas collisions is taken as the variable instead of pressure, then the quenching is the same within a gas family (mono- or diatomic) and it is temperature independent. So it is concluded that the effect depends on the number of gas collisions irrespective of the nature of the gas or its temperature.

An axiomatization of the nucleolus of the assignment game

[cat] En el domini dels jocs bilaterals d���assignaci��, es presenta una axiom��tica del nucleolus com l��unica soluci�� que compleix les propietats de consist��ncia respecte del joc derivat definit per Owen (1992) i monotonia de les queixes dels sectors respecte de la seva cardinalitat. Com a conseq����ncia obtenim una caracteritzaci�� geom��trica del nucleolus mitjan��ant una propietat de bisecci�� m��s forta que la que satisfan els punts del kernel (Maschler et al, 1979).

Gas collisions and pressure quenching of the photoluminescence of silicon nanopowder grown by plasma-enhanced chemical vapor deposition

The quenching of the photoluminescence of Si nanopowder grown by plasma-enhanced chemical vapor deposition due to pressure was measured for various gases ( H2, O2, N2, He, Ne, Ar, and Kr) and at different temperatures. The characteristic pressure, P0, of the general dependence I(P) = I0��exp(��P/P0) is gas and temperature dependent. However, when the number of gas collisions is taken as the variable instead of pressure, then the quenching is the same within a gas family (mono- or diatomic) and it is temperature independent. So it is concluded that the effect depends on the number of gas collisions irrespective of the nature of the gas or its temperature.

Coherent Stranski-Krastanov growth in 1+1 dimensions with anharmonic interactions: An equilibrium study

The formation of coherently strained three-dimensional (3D) islands on top of the wetting layer in the Stranski-Krastanov mode of growth is considered in a model in 1 + 1 dimensions accounting for the anharmonicity and nonconvexity of the real interatomic forces. It is shown that coherent 3D islands can be expected to form in compressed rather than expanded overlayers beyond a critical lattice misfit. In expanded overlayers the classical Stranski-Krastanov growth is expected to occur because the misfit dislocations can become energetically favored at smaller island sizes. The thermodynamic reason for coherent 3D islanding is incomplete wetting owing to the weaker adhesion of the edge atoms. Monolayer height islands with a critical size appear as necessary precursors of the 3D islands. This explains the experimentally observed narrow size distribution of the 3D islands. The 2D-3D transformation takes place by consecutive rearrangements of mono- to bilayer, bi- to trilayer islands, etc., after the corresponding critical sizes have been exceeded. The rearrangements are initiated by nucleation events, each one needing to overcome a lower energetic barrier than the one before. The model is in good qualitative agreement with available experimental observations.

An axiomatization of the nucleolus of the assignment game

[cat] En el domini dels jocs bilaterals d���assignaci��, es presenta una axiom��tica del nucleolus com l��unica soluci�� que compleix les propietats de consist��ncia respecte del joc derivat definit per Owen (1992) i monotonia de les queixes dels sectors respecte de la seva cardinalitat. Com a conseq����ncia obtenim una caracteritzaci�� geom��trica del nucleolus mitjan��ant una propietat de bisecci�� m��s forta que la que satisfan els punts del kernel (Maschler et al, 1979).

Inhibition of glutathione efflux in the perfused rat liver and isolated hepatocytes by organic anions and bilirubin. Kinetics, sidedness, and molecular forms.

Using isolated, in situ, single-pass perfused rat livers, incubations of freshly isolated hepatocytes, and sinusoidal membrane-enriched vesicles, we and others have shown the saturability of transport (efflux) of hepatic glutathione (GSH). These observations have implicated a carrier mechanism. Our present studies were designed to provide further evidence in support of a carrier mechanism for hepatic GSH efflux by demonstrating competition by liver-specific ligands which are taken up by hepatocytes. Perfusing livers with different substances, we found that: (a) sulfobromophthalein-GSH (BSP-GSH) had a dose-dependent and fully reversible inhibitory effect on GSH efflux, while GSH alone did not have any effect; (b) taurocholate had no inhibitory effect; (c) all of the organic anions studied, i.e., BSP, rose bengal, indocyanine green, and unconjugated bilirubin (UCB), manifested potent, dose-dependent inhibitory effects, with absence of toxic effects and complete reversibility of inhibition in the case of UCB. The inhibitory effects of UCB could be overcome partially by raising (CoCl2-induced) hepatic GSH concentration. Because of the physiological importance of UCB, we conducted a detailed study of its inhibitory kinetics in the isolated hepatocyte model in the range of circulating concentrations of UCB. Studies with Cl- -free media, to inhibit the uptake of UCB by hepatocytes, showed that the inhibition of GSH efflux by UCB is apparently from inside the cell. This point was confirmed by showing that the inhibition is overcome only when bilirubin-loaded cells are cleared of bilirubin (incubation with 5% bovine serum albumin). Using Gunn rat hepatocytes and purified bilirubin mono- and diglucuronides, we found that both UCB and glucuronide forms of bilirubin inhibit GSH efflux in a dose-dependent manner. We conclude that the organic anions, although taken up by a mechanism independent of GSH, may competitively inhibit the carrier for GSH efflux from inside the hepatocyte.

Synovial fluid examination for the diagnosis of synovial amyloidosis in patients with chronic renal failure undergoing haemodialysis

The diagnosis of synovial amyloidosis is based upon synovial biopsy. Synovial fluid (SF) in seven patients with amyloid arthropathy associated with chronic renal failure undergoing haemodialysis were studied. The SF and synovial samples of 10 consecutive patients with seronegative mono- or oligoarthritis served as controls. Six of the seven patients with amyloid positive synovial biopsy specimens showed amyloid in their SF. No amyloid was found in the synovial tissue or fluid of the 10 patients in the control group, the sensitivity being 87.7%. The finding of amyloid in SF was highly reproducible, showing its presence in the same joint on several occasions. The deposits were Congophilia resistant to potassium permanganate pretreatment, and the immunohistochemical analysis proved that they contained beta 2 microglobulin. The high sensitivity and good reproducibility of the method shows that the finding of amyloid in SF is sufficient for the diagnosis of synovial amyloidosis. It is possible to perform immunohis