Thermal modeling and management in ultrathin chip stack technology

This paper presents a thermal modeling for power management of a new three-dimensional (3-D) thinned dies stacking process. Besides the high concentration of power dissipating sources, which is the direct consequence of the very interesting integration efficiency increase, this new ultra-compact packaging technology can suffer of the poor thermal conductivity (about 700 times smaller than silicon one) of the benzocyclobutene (BCB) used as both adhesive and planarization layers in each level of the stack. Thermal simulation was conducted using three-dimensional (3-D) FEM tool to analyze the specific behaviors in such stacked structure and to optimize the design rules. This study first describes the heat transfer limitation through the vertical path by examining particularly the case of the high dissipating sources under small area. First results of characterization in transient regime by means of dedicated test device mounted in single level structure are presented. For the design optimization, the thermal draining capabilities of a copper grid or full copper plate embedded in the intermediate layer of stacked structure are evaluated as a function of the technological parameters and the physical properties. It is shown an interest for the transverse heat extraction under the buffer devices dissipating most the power and generally localized in the peripheral zone, and for the temperature uniformization, by heat spreading mechanism, in the localized regions where the attachment of the thin die is altered. Finally, all conclusions of this analysis are used for the quantitative projections of the thermal performance of a first demonstrator based on a three-levels stacking structure for space application.

Fossil resource depletion and climate change emissions: the role of physical constrictions

[spa] En lo que concierne al cambio climático, los pronósticos de cercanos picos de combustible fósiles parecen buenas noticias pues la mayoría de las emisiones proceden de la quema de combustibles fósiles. Sin embargo, esto podría resultar engañoso de confirmarse las enormes estimaciones de reservas de carbón pues puede divisarse un intercambio de combustible fósiles con baja concentración de carbono (petróleo y gas) por otros de mayor (carbón). Ciñéndonos a esta hipótesis desarrollamos escenarios donde tan pronto el petróleo y el gas natural alcanzan su cénit la extracción de carbón crece lo necesario para compensar el descenso de los primeros. Estimamos las emisiones que se deriva de tales supuestos y las comparamos con el peor escenario del IPCC. Si bien dicho escenario parece improbable concluimos que los picos de petróleo y gas no son suficientes para evitar peligrosas sendas de gases de efecto invernadero. Las concentraciones de CO2 halladas superan con creces las 450 ppm sin signos de remisión.

[Illustrations des Poètes maudits] / Luque, grav. ; Paul Verlaine, aut. du texte

Comprend : [Frontispice : portrait de] Paul Verlaine. [Cote : microfilm R 89553] ; [Fig. au chap. I : portrait de] Tristan Corbière. [Cote : microfilm R 89553] ; [Fig. au chap. II : portrait d'] Arthur Rimbaud. [Cote : microfilm R 89553] ; [Fig. au chap. III : portrait de] Stéphane Mallarmé. [Cote : microfilm R 89553] ; [Fig. au chap. IV : portrait de] Marceline Desbordes-Valmore. [Cote : microfilm R 89553] ; [Fig. au chap. V : portrait de] Villiers de l'Isle-Adam. [Cote : microfilm R 89553]

Intrauterine growth restriction is associated with structural alterations in human umbilical cord and decreased nitric oxide-induced relaxation of umbilical vein.

INTRODUCTION: Intrauterine growth restriction (IUGR) affects ∼8% of all pregnancies and is associated with major perinatal mortality and morbidity, and with an increased risk to develop cardiovascular diseases in adulthood. Despite identification of several risk factors, the mechanisms implicated in the development of IUGR remain poorly understood. In case of placental insufficiency, reduced delivery of oxygen and/or nutrients to the fetus could be associated with alterations in the umbilical circulation, contributing further to the impairment of maternal-fetal exchanges. We compared the structural and functional properties of umbilical cords from growth-restricted and appropriate for gestational age (AGA) term newborns, with particular attention to the umbilical vein (UV). METHODS: Human umbilical cords were collected at delivery. Morphological changes were investigated by histomorphometry, and UV's reactivity by pharmacological studies. RESULTS: Growth-restricted newborns displayed significantly lower growth parameters, placental weight and umbilical cord diameter than AGA controls. Total cross-section and smooth muscle areas were significantly smaller in UV of growth-restricted neonates than in controls. Maximal vasoconstriction achieved in isolated UV was lower in growth-restricted boys than in controls, whereas nitric oxide-induced relaxation was significantly reduced in UV of growth-restricted girls compared to controls. CONCLUSION: IUGR is associated with structural alterations of the UV in both genders, and with a decreased nitric oxide-induced relaxation in UV of newborn girls, whereas boys display impaired vasoconstriction. Further investigations will allow to better understand the regulation of umbilical circulation in growth-restricted neonates, which could contribute to devise potential novel therapeutic strategies to prevent or limit the development of IUGR.

Pregnancy outcome after methotrexate treatment for rheumatic disease prior to or during early pregnancy: a prospective multicenter cohort study.

OBJECTIVE: High-dose methotrexate (MTX) exposure during pregnancy is associated with embryopathy. The teratogenic potential of MTX at dosages typically used in the treatment of rheumatic diseases remains uncertain. The aim of this study was to evaluate the risk of spontaneous abortion, major birth defects, elective termination of pregnancy, shortened gestational age at delivery, and reduced birth weight in women exposed to MTX. METHODS: Pregnancy outcome in women taking MTX (≤30 mg/week) either after conception or within the 12 weeks before conception was evaluated in a prospective observational multicenter cohort study. Pregnancy outcomes in the MTX group were compared to outcomes in a group of disease-matched women and a group of women without autoimmune diseases (neither group was exposed to MTX). RESULTS: The study sample included 324 MTX-exposed pregnancies (188 exposed post-conception, 136 exposed pre-conception), 459 disease-matched comparison women, and 1,107 comparison women without autoimmune diseases. In the post-conception cohort, the cumulative incidence of spontaneous abortion was 42.5% (95% confidence interval [95% CI] 29.2-58.7), which was significantly higher than the incidence of spontaneous abortion in either comparison group. The risk of major birth defects (7 of 106 [6.6%]) was elevated compared to both the cohort of women without autoimmune diseases (29 of 1,001 [2.9%]) (adjusted odds ratio [OR] 3.1 [95% CI 1.03-9.5]) and the disease-matched cohort (14 of 393 [3.6%]) (adjusted OR 1.8 [95% CI 0.6-5.7]). None of the malformations were clearly consistent with MTX embryopathy. Neither the cumulative incidence of spontaneous abortion (14.4% [95% CI 8.0-25.3]) nor the risk of major birth defects (4 of 114 [3.5%]) was increased in the pre-conception cohort. Elective termination rates were increased in both of the MTX-exposed cohorts. There were no other significant differences among groups in other study end points. CONCLUSION: Post-conception administration of MTX at dosages typically used in the treatment of rheumatic diseases was associated with an increased risk of major birth defects and spontaneous abortion. Such evidence was not found among women in our pre-conception cohort.

Pregnancy outcome following exposure to topical retinoids: a multicenter prospective study.

Concerns have been raised about the use of topical retinoids since the publication of isolated cases of characteristic retinoid embryopathy, originally described after oral use. A collaborative study of the European Network of Teratology Information Services was carried out to evaluate the rate of congenital malformations following first-trimester topical retinoid exposure. A population of 235 exposed pregnant women was compared with 444 controls. No significant differences were observed between groups with regard to the rates of spontaneous abortion (odds ratio [95% confidence interval], 1.5 [0.8-2.7]), minor birth defects (1.3 [0.4-3.7]), and major birth defects (1.8 [0.6-5.4]). No child showed features of retinoid embryopathy. The rate of elective termination in the exposed group was increased 3-fold (3.4 [1.5-7.8]). In conclusion, these results do not suggest an increased risk of retinoid embryopathy. However, according to current knowledge, topical retinoids cannot be advised for use during pregnancy because their risk/benefit ratio remains questionable.

Risk-benefit balance assessment of SSRI antidepressant use during pregnancy and lactation based on best available evidence.

INTRODUCTION: Psychiatric disorders are among the leading causes of disability in Western societies. Selective serotonin reuptake inhibitors (SSRIs) are the most frequently prescribed antidepressant drugs during pregnancy and the postpartum period. Over the last decade, conflicting findings regarding the safety of SSRI drugs during pregnancy and lactation have questioned whether such treatments should be used during this period. AREAS COVERED: We discuss the main criteria that should be considered in the risk/benefit assessment of SSRI treatment in pregnant and/or breastfeeding patients (i.e., risks associated with SSRI use and with untreated depression as well as therapeutic benefits of SSRI and some alternative treatment strategies). For each criterion, available evidence has been synthesized and stratified by methodological quality as well as discussed for clinical impact. EXPERT OPINION: Currently, it is impossible for most of the evaluated outcomes to distinguish between the effects related to the mother's underlying disease and those inherent to SSRI treatment. In women suffering from major depression and responding to a pharmacological treatment, introduction or continuation of an SSRI should be encouraged in order to prevent maternal complications and to preserve maternal-infant bonding. The choice of the right drug depends above all on individual patient characteristics such as prior treatment response, diagnoses and comorbid conditions.

Comment prévenir les chutes chez les personnes âgées vivant à domicile: revue Cochrane pour le praticien. [How to prevent falls among elderly living at home]

Free fulltex: http://www.res_franco.cochrane.org/Files/ResumesRMS2009/Chutespersagees.pdf