Erythrocyte sodium lithium countertransport in normal and hypertensive pregnancy: relation to haemodynamic changes

OBJECTIVE: To establish the changes in erythrocyte sodium lithium countertransport (SLC) with advancing normal pregnancy and to determine if these changes were different in pregnancy induced hypertension (PIH). The changes in both groups were assessed in relation to haemodynamic changes. DESIGN: SLC, mean arterial pressure (MAP), cardiac output (CO) and total peripheral vascular resistance (TPVR) were determined serially during normal pregnancy and cross-sectionally in PIH. Women were studied again 20 weeks after delivery where possible. SETTING: Routine antenatal clinic and antenatal ward of a regional reference centre. SUBJECTS: Fifty-one normal primigravid women were studied serially and 41 primigravid women with PIH were studied at time of diagnosis. RESULTS: During normal pregnancy SLC (mmol Li/h/l cells) increased from a nonpregnant value of 0.24 +/- 0.02 (mean +/- SEM) to 0.32 +/- 0.02 at 14 weeks, and 0.37 +/- 0.02 at 20 weeks gestation. This was maintained until 38 weeks (0.40 +/- 0.02). The increase until 20 weeks occurred at the time of greatest change in CO (5.10 +/- 0.18 to 6.79 +/- 0.20 l/min) and TPVR (1327 +/- 58 to 969 +/- 33 dyn/s/cm-5). The decrease in TPVR with a rise in SLC is opposite to the relation reported in essential hypertension so that a functional relation is unlikely. However, the changes within pregnancy were positively correlated (r = 0.43, P < 0.01). In hypertensive pregnancies TPVR was elevated compared with normotensive pregnancies (1543 +/- 100 vs 1090 +/- 37) but the SLC was not different from that found in normotensive pregnancies (0.43 +/- 0.02 vs 0.40 +/- 0.02). CONCLUSIONS: The changes in SLC activity suggest dynamic effects on erythrocyte membrane function during pregnancy. However, no differences could be found between normal and hypertensive pregnancy and SLC is unlikely to be of value as a marker of hypertensive risk during pregnancy.     

A quadruple well, quadruple polysilicon BiCMOS process for fast 16Mb SRAM's

An advanced, high-performance, quadruple well, quadruple polysilicon BiCMOS technology has been developed for fast 16 Mb SRAM's. A split word-line bitcell architecture, using four levels of polysilicon and two self-aligned contacts, achieves a cell area of 8.61 μm² with conventional I-line lithography and 7.32 μm² with I-line plus phase-shift or with deep UV lithography. The process features PELOX isolation to provide a 1.0 μm active pitch, MOSFET transistors designed for a 0.80 μm gate poly pitch, a double polysilicon bipolar transistor with aggressively scaled parasitics, and a thin-film polysilicon transistor to enhance bitcell stability. A quadruple-well structure improves soft error rate (SER) and allows simultaneous optimization of MOSFET and bipolar performance     

Monolithic SiGe Up‐/Down‐Conversion Mixers with Active Baluns

The purpose of this paper is to describe the implementation of monolithically matching circuits, interface circuits, and RF core circuits to the same substrate. We designed and fabricated on‐chip 1 to 6 GHz up‐conversion and 1 to 8 GHz down‐conversion mixers using a 0.8 µm SiGe hetero‐junction bipolar transistor (HBT) process technology. To fabricate a SiGe HBT, we used a reduced pressure chemical vapor deposition (RPCVD) system to grow a base epitaxial layer, and we adopted local oxidation of silicon (LOCOS) isolation to separate the device terminals. An up‐conversion mixer was implemented on‐chip using an intermediate frequency (IF) matching circuit, local oscillator (LO)/radio frequency (RF) wideband matching circuits, LO/IF input balun circuits, and an RF output balun circuit. The measured results of the fabricated up‐conversion mixer show a positive power conversion gain from 1 to 6 GHz and a bandwidth of about 4.5 GHz. Also, the down‐conversion mixer was implemented on‐chip using LO/RF wideband matching circuits, LO/RF input balun circuits, and an IF output balun circuit. The measured results of the fabricated down‐conversion mixer show a positive power conversion gain from 1 to 8 GHz and a bandwidth of about 4.5 GHz.     

Effects of α‐form or β‐form nuclei on polymorphic crystalline morphology of poly(butylene adipate)

The effects of α‐form and β‐form nuclei on polymorphic morphology of poly(butylene adipate) (PBA) upon recrystallization from the molten state up to various T_max values were examined by differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD) and polarized light microscopy (PLM). In this study, PBA with complex melting and polymorphism behaviour was used as a model for examining different types and extents of residual nuclei. As the PBA initially containing the sole α‐crystal was brought to a molten state of various T_max, the extents of trace α‐form crystal nuclei varied and were dependent on T_max. Furthermore, it did not matter whether, initially, the PBA contained α‐ or β‐form crystals (or both) because only a single type of α‐nuclei could be left upon treatment to the molten liquid state at T_max. Therefore, only the α‐crystal in PBA had ‘memory capacity’ in the molten liquid state while the β‐crystal did not. This was so because the latter had been completely transformed into the solid state prior to being heated into a liquid. PBA crystallized before α‐nuclei could be packed into α‐crystal, regardless of the crystallization temperature (T_c). For recrystallization from molten PBA without any nuclei, the crystalline polymorphism was correspondingly influenced by T_c. Copyright © 2005 Society of Chemical Industry     

Error Concealment Based on Semantic Prioritization with Hardware‐Based Face Tracking

With video compression standards such as MPEG‐4, a transmission error happens in a video‐packet basis, rather than in a macroblock basis. In this context, we propose a semantic error prioritization method that determines the size of a video packet based on the importance of its contents. A video packet length is made to be short for an important area such as a facial area in order to reduce the possibility of error accumulation. To facilitate the semantic error prioritization, an efficient hardware algorithm for face tracking is proposed. The increase of hardware complexity is minimal because a motion estimation engine is efficiently re‐used for face tracking. Experimental results demonstrate that the facial area is well protected with the proposed scheme.     

New approach to enhance adhesions between carbon nanotube emitters and substrate by the combination of electrophoresis and successive electroplating

Complementary electroplating combined with electrophoresis enhanced the field emission characteristics of emitters by improving the adhesions between CNT emitters and substrate. The emitting current of the CNT emitters prepared by our combined method increased nine times higher than that of CNT emitters prepared by electrophoresis only, since electroplating improved the adhesion of CNT emitters. During the life-time measurement for 10 h, the emitting current of CNT emitters fabricated by electrophoresis only was drastically decreased to 13% of the initial current, while that prepared by the combination of electrophoresis and successive electroplating decreased to 64% of the initial current. We suggest that our method is a promising approach for the efficient fabrication of reliable CNT emitters.     

Epitaxial growth of GaN on (0001) Al<Subscript>2</Subscript>O<Subscript>3</Subscript> via solution-cast seed layer formation process using Ga(mDTC)<Subscript>3</Subscript>

This paper reports an alternative method for the growth of GaN epitaxial layer on (0001) Al₂O₃ substrate by hot-wall vapor phase epitaxy technique. Tris (N,N-dimethyldithiocarbamato)-gallium (III), Ga(mDTC)₃ was introduced as a precursor material for the seed layer formation in the growth of GaN. Optimal growth conditions with seed layers formed by the Ga(mDTC)₃ concentration of 0.047 mol/L were identified: Growth temperature was found to be 850 °C, and optimal distance between the reactant outlet and substrate was determined to be 12.5 cm. Characterization results showed that this growth method produce high-crystallinity GaN epitaxial layers at a relatively lower growth temperature compared to the existing growth techniques and simplify the growth process.     

High affinity hormone binding to the extracellular N-terminal exodomain of the follicle-stimulating hormone receptor is critically modulated by exoloop 3

The human follicle-stimulating hormone receptor (FSH-R) consists of two distinct domains of >330 amino acids, the N-terminal extracellular exodomain and membrane-associated endodomain. The exodomain alone binds hormone with high affinity, whereas the endodomain is the site of receptor activation. Coordination of these two domains is essential for successful hormone action but little is known about their functional and structural relationship. In this communication, we report that exoloop 3 of FSH-R constrains follicle-stimulating hormone binding to the exodomain. When the FSH-R exodomain was prepared by truncating its endodomain, the hormone binding affinity of the exodomain was slightly improved, compared with the wild type receptor. The binding affinity was further improved by >3-fold when the exodomain was attached to the membrane-associated domain of CD8. These results suggest that the FSH-R endodomain attenuates hormone binding at the exodomain. As a first step to test this hypothesis, the 11 amino acids except Ala589 of exoloop 3 were individually substituted with Ala. Ala substitution for Leu583 or Ile584 improved the hormone binding affinity by 4-6-fold while totally abolishing cAMP induction, indicating an inverse relationship. The Ala substitution for Lys580 or Pro582 had a similar trend but to a lesser extent. This significant improvement in the binding affinity suggests that the four residues at the N-terminal region of exoloop 3 interact with the exodomain and constrain the hormone binding in the wild type receptor. This effect is specific since substitutions for other than the 4 residues did not improve the hormone binding affinity. Computer modeling shows that the 4 residues can be positioned on one side of exoloop 3. This result and the apparent inverse relationship of hormone binding and cAMP induction suggest that these two essential functions may work against each other. Therefore, hormone binding might be compromised to preserve cAMP inducibility while maintaining a reasonably high, but below maximum, binding affinity.