Anomalous material-dependent transport of focused, laser-driven proton beams.

Intense lasers can accelerate protons in sufficient numbers and energy that the resulting beam can heat materials to exotic warm (10 s of eV temperature) states. Here we show with experimental data that a laser-driven proton beam focused onto a target heated it in a localized spot with size strongly dependent upon material and as small as 35 µm radius. Simulations indicate that cold stopping power values cannot model the intense proton beam transport in solid targets well enough to match the large differences observed. In the experiment a 74 J, 670 fs laser drove a focusing proton beam that transported through different thicknesses of solid Mylar, Al, Cu or Au, eventually heating a rear, thin, Au witness layer. The XUV emission seen from the rear of the Au indicated a clear dependence of proton beam transport upon atomic number, Z, of the transport layer: a larger and brighter emission spot was measured after proton transport through the lower Z foils even with equal mass density for supposed equivalent proton stopping range. Beam transport dynamics pertaining to the observed heated spot were investigated numerically with a particle-in-cell (PIC) code. In simulations protons moving through an Al transport layer result in higher Au temperature responsible for higher Au radiant emittance compared to a Cu transport case. The inferred finding that proton stopping varies with temperature in different materials, considerably changing the beam heating profile, can guide applications seeking to controllably heat targets with intense proton beams.

How high energy fluxes may affect Rayleigh-Taylor instability growth in young supernova remnants.

Energy-transport effects can alter the structure that develops as a supernova evolves into a supernova remnant. The Rayleigh-Taylor instability is thought to produce structure at the interface between the stellar ejecta and the circumstellar matter, based on simple models and hydrodynamic simulations. Here we report experimental results from the National Ignition Facility to explore how large energy fluxes, which are present in supernovae, affect this structure. We observed a reduction in Rayleigh-Taylor growth. In analyzing the comparison with supernova SN1993J, a Type II supernova, we found that the energy fluxes produced by heat conduction appear to be larger than the radiative energy fluxes, and large enough to have dramatic consequences. No reported astrophysical simulations have included radiation and heat conduction self-consistently in modeling supernova remnants and these dynamics should be noted in the understanding of young supernova remnants.

Grain-size-independent plastic flow at ultrahigh pressures and strain rates.

A basic tenet of material science is that the flow stress of a metal increases as its grain size decreases, an effect described by the Hall-Petch relation. This relation is used extensively in material design to optimize the hardness, durability, survivability, and ductility of structural metals. This Letter reports experimental results in a new regime of high pressures and strain rates that challenge this basic tenet of mechanical metallurgy. We report measurements of the plastic flow of the model body-centered-cubic metal tantalum made under conditions of high pressure (>100 GPa) and strain rate (∼10(7) s(-1)) achieved by using the Omega laser. Under these unique plastic deformation ("flow") conditions, the effect of grain size is found to be negligible for grain sizes >0.25 µm sizes. A multiscale model of the plastic flow suggests that pressure and strain rate hardening dominate over the grain-size effects. Theoretical estimates, based on grain compatibility and geometrically necessary dislocations, corroborate this conclusion.

Time-resolved compression of a capsule with a cone to high density for fast-ignition laser fusion.

The advent of high-intensity lasers enables us to recreate and study the behaviour of matter under the extreme densities and pressures that exist in many astrophysical objects. It may also enable us to develop a power source based on laser-driven nuclear fusion. Achieving such conditions usually requires a target that is highly uniform and spherically symmetric. Here we show that it is possible to generate high densities in a so-called fast-ignition target that consists of a thin shell whose spherical symmetry is interrupted by the inclusion of a metal cone. Using picosecond-time-resolved X-ray radiography, we show that we can achieve areal densities in excess of 300 mg cm(-2) with a nanosecond-duration compression pulse--the highest areal density ever reported for a cone-in-shell target. Such densities are high enough to stop MeV electrons, which is necessary for igniting the fuel with a subsequent picosecond pulse focused into the resulting plasma.

Precision shock tuning on the national ignition facility.

Ignition implosions on the National Ignition Facility [J. D. Lindl et al., Phys. Plasmas 11, 339 (2004)] are underway with the goal of compressing deuterium-tritium fuel to a sufficiently high areal density (ρR) to sustain a self-propagating burn wave required for fusion power gain greater than unity. These implosions are driven with a very carefully tailored sequence of four shock waves that must be timed to very high precision to keep the fuel entropy and adiabat low and ρR high. The first series of precision tuning experiments on the National Ignition Facility, which use optical diagnostics to directly measure the strength and timing of all four shocks inside a hohlraum-driven, cryogenic liquid-deuterium-filled capsule interior have now been performed. The results of these experiments are presented demonstrating a significant decrease in adiabat over previously untuned implosions. The impact of the improved shock timing is confirmed in related deuterium-tritium layered capsule implosions, which show the highest fuel compression (ρR~1.0 g/cm(2)) measured to date, exceeding the previous record [V. Goncharov et al., Phys. Rev. Lett. 104, 165001 (2010)] by more than a factor of 3. The experiments also clearly reveal an issue with the 4th shock velocity, which is observed to be 20% slower than predictions from numerical simulation.

Avances clínicos en calcificación vascular / No disponible

Se han seleccionado los artículos que aportan respuestas alas preguntas de más interés desde el punto de vista clínicoen cuanto a la calcificación vascular.1. ¿Cómo se mide?: Se analizan estudios que ponen demanifiesto la utilidad de diferentes herramientas paracuantificarla.2. ¿Qué mide?: En pacientes en diálisis como en la poblacióngeneral la calcificación vascular y la rigidez arterialson factores pronósticos de morbi-mortalidad. Otrosmarcadores como la fetuína A, se asocian a mortalidaden pacientes en hemodiálisis pero no en pacientes enestadios precoces de enfermedad renal crónica.3. ¿Qué la provoca?: En dos estudios seleccionados vuelvea demostrarse que el bajo recambio óseo y la diabetescondicionan enfermedad cardiovascular y calcificaciónvascular respectivamente.4. ¿Cómo se trata?: Aún no existe evidencia clínica de regresiónde la calcificación vascular. Sin embargo, enun estudio prospectivo en pacientes incidentes en hemodiálisisse demuestra que el sevelamer comparadocon los compuestos de calcio atenúa la progresión dela calcificación vascular y confiere mayor supervivencia.En un estudio en pacientes prevalentes, comparandoambos compuestos, el sevelamer sólo beneficiaen supervivencia a pacientes mayores de 65 años.Queda por demostrar en estudios clínicos prospectivossi el paricalcitol y el cinacalcet confirman los buenosresultados experimentales (AU)

The articles providing answers to the questions on vascular calcificationof most interest from a clinical point of view were selected.1. How is it measured?: Studies showing the clinical utility ofdifferent tools to quantify it were analyzed.2. What does it measure?: Both in dialysis patients and the generalpopulation, vascular calcification and arterial stiffnessare prognostic factors for morbidity and mortality. Other markerssuch as fetuin-A are associated with mortality in patientson hemodialysis but not in patients in early stages of chronickidney disease.3. What causes it?: In two selected studies, it was demonstratedagain that low bone turnover and diabetes cause cardiovasculardisease and vascular calcification, respectively.4. How is it treated?: There is still no clinical evidence of regressionof vascular calcification. However, a prospective study innew hemodialysis patients showed that sevelamer comparedto calcium compounds slows the progression of vascular calcificationand confers greater survival. A study comparingboth compounds in chronic hemodialysis patients showedthat sevelamer only had a benefit on survival in patients olderthan 65 years. It remains to be demonstrated whether thegood experimental results of paricalcitol and cinacalcet areconfirmed in prospective clinical studies (AU)

Control del fósforo y tratamiento con vitamina D enEnfermedad Renal Crónica antes del inicio de diálisis / No disponible

La hiperfosfatemia es una complicación que aparece ya enestadios tempranos de la enfermedad renal crónica (ERC) yque ha demostrado tener graves consecuencias en los pa-cientes con nefropatía. En la actualidad se están estudiadonuevos reguladores del fósforo como son el FGF-23, unahormona fosfatúrica y contra-reguladora de la vitamina D,y kloto, co-factor necesario para la activación del FGF-23.Las principales consecuencias de la hiperfosfatemia descri-tas en pacientes con ERC no en diálisis son la calcificaciónectópica, el incremento de la mortalidad y la más rápidaprogresión de la ERC. Todo ello indica la necesidad de bus-car un control estricto del Pi. Para ello, destacan en la ac-tualidad dos fármacos como son el carbonato de lantano yel sevelamer. Aunque no existen estudios diseñados espe-cíficamente para esta población aún no en diálisis, parecenser fármacos eficaces y seguros. Otra complicación de laERC es el defecto en la síntesis de vitamina D que segúnlos estudios publicados recientemente, ha resultado sermás prevalente y aparecer en estadios más tempranos dela enfermedad de lo que se creía inicialmente. Existe unamplio debate respecto a la necesidad de administrar su-plementos de vitamina D de forma sistemática por losefectos pleiotrópicos de dicha hormona, ajenos al desarro-llo de la enfermedad ósea renal. Por esas dudas, si bien nohay acuerdo en la administración rutinaria, sí hay consen-so en la necesidad de medir los valores de 1,25-dihidroxivi-tamina D y 25-hidroxivitamina D, así como esperar el re-sultado de los numerosos estudios que se están llevandoacabo acerca del impacto de la vitamina D en la progresiónde factores de riesgo cardiovascular, en la ERC y las posi-bles consecuencias de su administración indiscriminada (AU)

Hyperphosphatemia is a complication that appears in the earlystages of chronic kidney disease (CKD) and that has been shownto have serious consequences in kidney disease patients. Newphosphate regulators are currently being studied such as FGF-23, a counter-regulatory phosphaturic hormone for vitamin D,and klotho, a cofactor necessary for activation of FGF-23. Themain consequences of hyperphosphatemia described in CKD patientsnot on dialysis are ectopic calcification, increased mortalityand more rapid progression of CKD. All this indicates the needfor strict control of Pi. The two most currently used drugs for thispurpose are lanthanum carbonate and sevelamer. Althoughthere are no studies specifically designed for this predialysis population,these drugs appear to be effective and safe. Anothercomplication of CKD is vitamin D deficiency which, according torecently published studies, is more prevalent and appears in earlierstages of the disease than was initially thought. There is widedebate on the need to administer vitamin D supplements systematicallydue to the pleiotropic effects of this hormone andwhich are unrelated to development of renal bone disease. Becauseof these doubts, there is no agreement on routine administration,although there is consensus on the need to measure1,25-dihydroxyvitamin D and 25-hydroxyvitamin D values and towait for the result of numerous studies that are being carriedout on the impact of vitamin D on progression of cardiovascularrisk factors in CKD and the possible consequences of its indiscriminateadministration (AU)

[Clinical advances in vascular calcification]. / Avances clínicos en calcificación vascular.

The articles providing answers to the questions on vascular calcification of most interest from a clinical point of view were selected. 1. How is it measured?: Studies showing the clinical utility of different tools to quantify it were analyzed. 2. What does it measure?: Both in dialysis patients and the general population, vascular calcification and arterial stiffness are prognostic factors for morbidity and mortality. Other markers such as fetuin-A are associated with mortality in patients on hemodialysis but not in patients in early stages of chronic kidney disease. 3. What causes it?: In two selected studies, it was demonstrated again that low bone turnover and diabetes cause cardiovascular disease and vascular calcification, respectively. 4. How is it treated?: There is still no clinical evidence of regression of vascular calcification. However, a prospective study in new hemodialysis patients showed that sevelamer compared to calcium compounds slows the progression of vascular calcification and confers greater survival. A study comparing both compounds in chronic hemodialysis patients showed that sevelamer only had a benefit on survival in patients older than 65 years. It remains to be demonstrated whether the good experimental results of paricalcitol and cinacalcet are confirmed in prospective clinical studies.

[Control of phosphorus and treatment with vitamin D in chronic kidney disease prior to the start of dialysis]. / Control del fósforo y tratamiento con vitamina D en Enfermedad Renal Crónica antes del inicio de diálisis.

Hyperphosphatemia is a complication that appears in the early stages of chronic kidney disease (CKD) and that has been shown to have serious consequences in kidney disease patients. New phosphate regulators are currently being studied such as FGF- 23, a counter-regulatory phosphaturic hormone for vitamin D, and klotho, a cofactor necessary for activation of FGF-23. The main consequences of hyperphosphatemia described in CKD patients not on dialysis are ectopic calcification, increased mortality and more rapid progression of CKD. All this indicates the need for strict control of Pi. The two most currently used drugs for this purpose are lanthanum carbonate and sevelamer. Although there are no studies specifically designed for this predialysis population, these drugs appear to be effective and safe. Another complication of CKD is vitamin D deficiency which, according to recently published studies, is more prevalent and appears in earlier stages of the disease than was initially thought. There is wide debate on the need to administer vitamin D supplements systematically due to the pleiotropic effects of this hormone and which are unrelated to development of renal bone disease. Because of these doubts, there is no agreement on routine administration, although there is consensus on the need to measure 1,25-dihydroxyvitamin D and 25-hydroxyvitamin D values and to wait for the result of numerous studies that are being carried out on the impact of vitamin D on progression of cardiovascular risk factors in CKD and the possible consequences of its indiscriminate administration.

Laser heating of solid matter by light-pressure-driven shocks at ultrarelativistic intensities.

The heating of solid targets irradiated by 5 x 10(20) W cm(-2), 0.8 ps, 1.05 microm wavelength laser light is studied by x-ray spectroscopy of the K-shell emission from thin layers of Ni, Mo, and V. A surface layer is heated to approximately 5 keV with an axial temperature gradient of 0.6 microm scale length. Images of Ni Ly(alpha) show the hot region has 100 G bar light pressure compresses the preformed plasma and drives a shock into the solid, heating a thin layer.

[Postpartum hemolytic uremic syndrome: a rare entity and a treatment challenge]. / Síndrome hemolítico-urémico post-parto: entidad rara de manejo complejo.

Hemolytic uremic syndrome (HUS) is a rare entity that in 7% of cases has been related to oral contraceptives, pregnancy and puerperium, In this clinical setting prognosis is worse and renal replacement therapy is usually needed. Different authors agree that plamapheresis is the treatment of choice, and has improved patient survival to 80-90%. We describe a case of a young woman that 10 days postpartum developed thrombocytopenia, microangiopathic hemolytic anemia and acute renal failure with nephrotic range proteinuria. With the suspicion of HUS she was started on plasmapheresis initially stopped due to an anaphylactic reaction to plasma and finally due to hyperhidratation with acute pulmonary edema needing mechanical ventilation. Renal biopsy confirmed the diagnosis. Clinical course was complicated with refractory hypertension and infectious complications In conclusion postpartum HUS is a rare clinical entity , that forces a differential diagnosis with hypertensive complications of pregnancy. It is associated to multiple complications difficult to handle during follow-up. Plasmapheresis treatment adds complexity to clinical care but is the only treatment of proven efficacy in order to improve survival and renal prognosis.

Síndrome hemolítico-urémicopost-parto: entidad rara de manejo complejo / No disponible

El síndrome hemolítico urémico (SHU) es una entidad de escasa incidencia, donde un 7% de casos se asocia a la toma de anticonceptivos orales, al embarazo y al puerperio, siendo tales casos de peor pronóstico, pues frecuentemente necesitan tratamiento renal sustitutivo1. Distintos autores coinciden en que la plasmaféresis es la terapia de elección, que ha mejorado la supervivencia a 80-90%2,3. Describimos el caso de una joven que en el décimo día del puerperio presenta plaquetopenia, anemia hemolíticamicroangiopática (AHM), e insuficiencia renal con proteinuria nefrótica. Con la orientación de SHU se pauta plasmaféresis, que se suspende inicialmente por alergia al plasma infundido, y definitivamente por hiperhidratación con edema agudo de pulmón (EAP) que precisa ventilación mecánica. La biopsia renal confirma el diagnóstico de presunción. La evolución resulta tórpida, marcada por la hipertensión arterial (HTA) refractaria y complicaciones infecciosas. En conclusión, el SHU post-parto es una patología poco frecuente, que asocia muchas complicaciones de difícil manejo a lo largo de su evolución y que obliga al diagnóstico diferencial con los estados hipertensivos del embarazo4. A su vez, el tratamiento con plasmaféresis añade complejidad al cuadro, pero es el único procedimiento que ha demostrado mejorar la supervivencia y el pronóstico renal (AU)

Hemolytic uremic syndrome (HUS) is a rare entity that in 7% of cases has been related to oral contraceptives, pregnancy and puerperium, In this clinical setting prognosis is worse and renal replacement therapy is usually needed. Different authors agree that plamapheresis is the treatment of choice, and has improved patient survival to 80-90%. We describe a case of a young woman that 10 days postpartum developed thrombocytopenia, microangiopathic hemolytic anemia and acute renal failure with nephritic range proteinuria. With the suspiction of HUS she was started on plasmapheresis initially stopped due to an anaphylactic reaction to plasma and finally due to hyperhidratation with acute pulmonary edema needing mechanical ventilation. Renal biopsy confirmed the diagnosis. Clinical course was complicated with refractory hypertension and infectious complications In conclusion postpartum HUS is a rare clinical entity , that forces a differential diagnosis with hypertensive complications of pregnancy. It is associated to multiple complications difficult to handle during follow-up. Plasmapheresis treatment adds complexity to clinical care but is the only treatment of proven efficacy in order to improve survival and renal prognosis (AU)

Situación clínica del paciente en el momento de iniciar diálisis. Estudio INESIR / Clinical status of the patient at the time of dialysis onset: INESIR study

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Eficiencia de implantar en atención primaria un programa dirigido a conseguir la referencia precoz al nefrólogo de los pacientes con insuficiencia renal crónica / Efficiency of implementing a program aimed at achieving early referral to the nephrologist of patients with chronic renal failure in primary care

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Entomological aspects of Chagas' disease transmission in the domestic habitat, Argentina.

OBJECTIVE: To study the risk of Trypanosoma cruzi domestic transmission using an entomological index and to explore its relationship with household's characteristics and cultural aspects. METHODS: There were studied 158 households in an endemic area in Argentina. Each household was classified according to an entomological risk indicator (number of risky bites/human). A questionnaire was administered to evaluate risk factors among householders. RESULTS: Infested households showed a wide range of risk values (0 to 5 risky bites/human) with skewed distribution, a high frequency of lower values and few very high risk households. Of all collected Triatoma infestans, 44% had had human blood meals whereas 27% had had dogs or chickens blood meals. Having dogs and birds sharing room with humans increased the risk values. Tidy clean households had contributed significantly to lower risk values as a result of low vector density. The infested households showed a 24.3% correlation between time after insecticide application and the number of vectors. But there was no correlation between the time after insecticide application and T. infestans' infectivity. The statistical analysis showed a high correlation between current values of the entomological risk indicator and Trypanosoma cruzi seroprevalence in children. CONCLUSIONS: The risk of T. cruzi domestic transmission assessed using an entomological index show a correlation with children seroprevalence for Chagas' disease and householders' habits.