High-speed planar-structure Inp/InGaAsP/InGaAs avalanche photodiode grown by VPE

Planar-structure InP/InGaAsP/InGaAs avalanche photo-diodes have been realised by using a VPE-growth technique and a Be+ implanted guard ring. Sensitivity measurement has been performed at 1.3 ?m and 1.8 Gbit/s. The minimum average received level required for 10?9 BER was ?31.3 dBm, which was 1.2 dB better than the value for the Ge-APD.     

Pure red cell aplasia and myasthenia gravis with thymoma: a case report and review of the literature

In women, osteoporosis with fractures can happen between 50 years, the age of the menopause, and 80 years. Over these three decades, the condition of bone metabolism is not the same. The years after menopause present with high bone turnover. During these years, the administration of antiresorptive drugs is promising: Estrogens (plus progestagens), calcitonins, bisphosphonates. About 10 years after the menopause bone turnover slows down to low turnover. Now the administration of bone-formation stimulating agents is to be preferred: fluorides in the first line, perhaps anabolics in single cases. The prominent fracture of women older than 75 years is the hip fracture (type II osteoporosis). Bone turnover mostly is accelerated again, now due to secondary hyperparathyroidism as a consequence of long-lasting calcium and vitamin D deficiency. For treatment, calcium plus vitamin D is recommended. The exact diagnosis of the metabolic status of the skeleton is a prerequisite for the choice of the optimal therapeutic principle.     

InP-lnGaAsP planar avalanche photodiodes with self-guard-ring effect

Marked diode characteristics dependence on the distance between p-n junction and heterointerface in double heterojunction InP-InGaAsP planar a.p.d.s is described. In a diode with an optimised configuration, as high as 3000 maximum avalanche gain and less than 3×10?6 A/cm2 dark-current density at 0.9 VB are achieved.     

LanV, a bifunctional enzyme: aromatase and ketoreductase during landomycin A biosynthesis

LanV is involved in the biosynthesis of landomycin A. The exact function of this enzyme was elucidated with combinatorial biosynthesis by using Streptomyces fradiae mutants that produce urdamycin A. After expression of lanV in S. fradiae DeltaurdM, which is a mutant that accumulates rabelomycin, urdamycinon B and urdamycin B were found to be produced by the strain. This result indicates that LanV is involved in the 6-ketoreduction of the angucycline core, which preceeds a 5,6-dehydration reaction. 9-C-D-Olivosyltetrangulol was also produced by this strain; this demonstrates that LanV catalyses the aromatization of ring A of the angucycline structure. Coexpression of lanV and lanGT2 in S. fradiae AO, a mutant that lacks all four urdamycin glycosyltransferases, resulted in the production of tetrangulol and the glycoside landomycin H, both of which have an aromatic ring A. As glycosylated angucyclines were not observed after expression of lanGT2 in the absence of lanV, we conclude that LanGT2 needs an aromatized ring A for substrate recognition.     

Formation of magnesium silicate hydrate and its crystallization to talc

Mixtures of Mg(OH)₂ and colloidal silica with Mg/Si = 0.75 were treated hydrothermally at 180° to 600°C for 4 h ? 8 weeks. Reaction seemed always to proceed through the formation of magnesium silicate hydrate to talc, which had random displacements of layers parallel to b of nb/3, and gave a decrease of the basal spacing with increase of crystallinity. The magnesium silicate hydrate gave X-ray powder patterns indicative of two-dimensional crystals without basal spacing, had a specific area of about 300 m²/g, and gave an exotherm at 830°C. Dehydration and infrared spectra for products are also described.