Optical properties and laser performance of neodymium doped fluoroapatites SrxCa5−x(PO4)3F (x = 0, 1, 2, 3, 4, and 5)

Nd doped fluoroapatites Sr_xCa_5−x(PO₄)₃F(S_xC_5−xPF, X = 0, 1, 2, 3, 4, and 5) single crystals have been grown by the Czochralski technique. Their polarized absorption and emission spectra have been recorded at room temperature and used to calculate the absorption and stimulated emission cross sections. Broadening of the absorption and emission bands is observed for Nd³⁺ in the solid solutions SPF-CPF compared to Nd³⁺ in CPF or SPF. 1% Nd:S_xC_5−xPF, X = 0, 2, 3, 4, and 5, laser rods have been tested in a cavity longitudinally pumped by a 1 W AlGaAs laser diode and compared to Nd:YAG and Nd:YVO₄ rods. All fluoroapatites exhibit very good laser performance with low thresholds and high slope efficiencies, higher than in the case of YAG and equal to the YVO₄ samples. The dependance of the laser output power versus the diode temperature has also been measured for all materials. The laser output was found to be as sensitive to the diode temperature fluctuations for fluoroapatites as for YAG.     

A new well-conditioned Integral formulation for Maxwell equations in three dimensions

We present a new boundary integral equation dedicated to the solution of the boundary problem of a perfectly electrically conducting surface for the harmonic Maxwell equations in unbounded domains. Any solution of the harmonic Maxwell equations is represented as the electromagnetic field generated by a combination of electric and magnetic potentials. These potentials are those appearing in the classical combined field integral equation (CFIE), but their coupling is realized by an operator Y/spl tilde//sup +/ instead of a coefficient. Therefore, the integral equation obtained can be viewed as a generalization of the CFIE. In this paper, we propose an explicit construction of the coupling operator Y/spl tilde//sup +/ which is designed to approximate the exterior admittance operator of the scattering obstacle. A local approximation by the admittance operator of the tangential plane seems to be relevant thanks to the localization effects related to high-frequency phenomena. The provided numerical simulations show that this formulation leads to linear systems that are better conditioned compared to more classical integral equations, which speeds up the resolution when solved with iterative techniques.     

Effect of anti-carrier antibody on carrier-determined tolerance

These experiments were originally designed to determine whether an anti-carrier antibody, e.g., anti-allotype could break hapten-specific tolerance in vivo. Tolerance to 2,4-dinitrophenyl (DNP) was induced in C57BL/6J mice using DNP-BALB/c IgG2a conjugate. When anti-allotype serum was injected in C57BL/6J mice one day after a single injection of DNP-IgG2a the mice were not tolerant. In contrast, when tolerance was induced by four weekly injections of tolerogen, the anti-allotype serum had no effect on the tolerant state. This effect was specific for tolerance-inducing carrier. Anti-carrier antibody injected in C57BL/6J mice one day after DNP-IgG2a produced a small but significant anti-DNP response without administration of the immunogen, whereas the tolerogen (DNP-IgG2a) by itself was not immunogenic. Similarly, despite multiple injections of DNP-IgG2a bearing the foreign allotype, only one out of 7 C57BL/6J mice showed a weak anti-carrier response. In contrast, a marked anti-carrier (IgG2a) response was obtained when the anti-allotype antibody was passively administered in C57BL/6J mice. In conclusion, these experiments suggest that tolerance to an antigenic determinant may be broken by an antibody directed not to this determinant, but to another on the same molecule. The significance of this finding in relationship to the mechanism of the carrier-determined tolerance and the breakdown of self-tolerance is discussed.     

Alkaline earth titanoniobates with a layer structure : A0.5H(TiNbO5)2.nH2O

The ion exchange properties of the layer oxide HTiNbO₅ in the presence of alkaline earth acetate solution A(CH₃COO)₂ has been investigated. The maximum exchange rate increases with the size of the A ion, leading to the hydrates : Ba(TiNbO₅)₂.4H₂O, Sr_0.75H_0.50(TiNbO₅)₂.4H₂O and Ca_0.50H(TiNbO₅)₂.4H₂O. The minimum exchange rate corresponds to the definite compounds A_0.5H(TiNbO₅)₂.4H₂O, labelled 4W-hydrates. The study of the thermal stability of the 4W-hydrates leads to the hydrates A_0.5H(TiNbO₅)₂.2H₂O and A_0.5H(TiNbO₅)₂.H₂O, and finally to the dehydrated oxides A_0.5H(TiNbO₅)₂. The reversibility of the ion exchange reaction and of the hydration phenomenon has been studied. The X-ray diffraction study of these compounds shows that the structure of the (TiNbO₅) layers is conserved whatever the nature of the A ion and of the hydrate may be. The structural evolution versus water content and size of the A ions is discussed.     

Crystal Structure of the Human Monoacylglycerol Lipase,a Key Actor in Endocannabinoid Signaling

2‐Arachidonoylglycerol plays a major role in endocannabinoid signaling, and is tightly regulated by the monoacylglycerol lipase (MAGL). Here we report the crystal structure of human MAGL. The protein crystallizes as a dimer, and despite structural homologies to haloperoxidases and esterases, it distinguishes itself by a wide and hydrophobic access to the catalytic site. An apolar helix covering the active site also gives structural insight into the amphitropic character of MAGL, and likely explains how MAGL interacts with membranes to recruit its substrate. Docking of 2‐arachidonoylglycerol highlights a hydrophobic and a hydrophilic cavity that accommodate the lipid into the catalytic site. Moreover, we identified Cys201 as the crucial residue in MAGL inhibition by N‐arachidonylmaleimide, a sulfhydryl‐reactive compound. Beside the advance in the knowledge of endocannabinoids degradation routes, the structure of MAGL paves the way for future medicinal chemistry works aimed at the design of new drugs exploiting 2‐arachidonoylglycerol transmission.     

Design automation in MEDEA: present and future

The semiconductor industry has been growing at an unprecedented level since its start in the early 1960s. Capitalizing on the outstanding properties of silicon and its stable oxide permitted the introduction of the CMOS industry, the leading semiconductor industry process. However, the average 15% to 16% annual growth in semiconductor sales has also presented tremendous problems of huge investments in manufacturing. Mandatory now is a rapid return of investment through advanced products (in the latest available processes) that have high added value at the system level. Sometimes the system is the product itself, which raises thoughts of new ways to design these complex systems on a single chip that mixes several functionalities. This article explores a future European evolution of design automation, discussing the present status of Europe's lack of local industrial developments as well as its tremendous knowledge reservoir. Earlier MEDEA activities paved the road to new design solutions and gave European companies the chance to influence US developments, as is evidenced by frequent technology partnerships with US software vendors. Recently, we have seen a significant increase in European start-ups in advanced design automation domains (hardware-software codesign, intellectual property reuse, deep-submicron effects)     

Millimeter wave backscatter from deciduous trees

Measurements of the millimeter-wave backscatter from deciduous (leafed) trees are explained using a simple scattering model. The backscatter from individual leaves was measured in the laboratory and used to justify the use of an average leaf radar cross section when computing the normalized radar cross section (NRCS) of tree canopies. NRCS measurements of canopies show that the direction in which incident radiation impinges on the canopy is an important factor in characterizing radar backscatter. Comparisons of measured NRCS values demonstrate that planophil and erectophil trees can be distinguished based on their backscatter at 215 GHz     

Parenteral glutamine infusion alters insulin-mediated glucose metabolism

There is no consensus of opinion on the treatment of hypertensive putaminal hemorrhage (HPH), especially in patients older than 65 years. The purpose of this study was to study the surgical outcome of HPH in patients older than 65 years while considering mortality and activity of daily life. Among eighty-three patients aged 65 or older with HPH, fifty-one patients received only medical treatment and 32 were operated upon to remove the hematoma. Each patient was measured by the intracerebral hemorrhage-intracranial hemorrhage grading scale (ICH Grade) which used the sum of eye opening and motor response scores derived from Glasgow Coma Scale. The cubic content of the HPH was calculated from measurement of maximum width (X), length (Y) and height (Z), and the hematoma volume taken as 1/2 that volume (X. Y. Z/2). The acute mortality in surgically treated group was 40.6% and three patients died during the follow-up period from one to six months after the operation. Determinant for the prognosis was the ICH grade and the volume of the hematoma. Patients who returned to ADL 1 and 2 (good recovery) after surgical treatment were 40.0% in ICH Grade I, 16.7% in ICH Grade II, and 20.0% in ICH Grade III. Among those patients who were in ICH Grade IV, none had good recovery. The acute mortality was zero in ICH Grade I, 16.7% in ICH Grade II, 40.0% in ICH Grade III, and 62.5% in ICH Grade IV. The crucial size was 60 ml with a mortality of 77.8% for hematomas larger and 39.1% for hematomas smaller than that. From our lim ited experience, we learned that operation in elderly patients with HPH was considered only in patients with hematomas between 20 to 60 ml, with a high operative mortality and only one-fourth having a good recovery postoperatively.