Fibre management technique for optical device integration oncircuit board with hundreds of optical connections

The authors present a technique for fibre management on a circuit board, which utilises newly-developed, flexible optical fibre circuits and multifibre physical contact connectors. The technique achieves compact fibre wiring and easy fibre connection for hundreds of fibres on a circuit board. The authors have fabricated a compact 8×16 delivery and coupling switch board using the technique     

A high-speed low-power tri-state driver flip flop for ultra-lowsupply voltage GaAs heterojunction FET LSI's

This paper describes a low-supply-voltage flip flop circuit design. The advantages of low supply voltage are discussed. Based on an analytical circuit delay model, conventional flip flop operating speed degradation below 1 V supply voltage is analyzed. We then propose a new GaAs static flip flop, called TD-FF (tri-state driver flip-flop), for ultra-low supply voltage GaAs heterojunction FET LSIs. The TD-FF operates at a data rate of 10 Gbps with 18 mW power consumption at 0.8 V supply voltage, which is 1/5 of the minimum value reported for D-FFs so far. We also demonstrate a 1/8 static frequency divider IC using the TD-FF configuration. This IC operates up to 10 GHz with 38 mW at 0.8 V supply voltage     

Ceramide inhibits inwardly rectifying K+ currents via a Ras- and Raf-1-dependent pathway in cultured oligodendrocytes

Ceramide is a lipid mediator implicated in apoptosis induced by proinflammatory cytokines in many cell types, including oligodendrocytes (OLGs). To determine whether ceramide modulates transmembrane signaling events in OLGs, we studied its effect on intracellular Ca2+ (Cai), resting membrane potential and inwardly rectifying K+ currents (IKir) in cultured neonatal rat OLGs. We report here that (1) exposure to C2-ceramide (cer) rarely increases OLG Cai, whereas sphingosine elicits sustained increase in Cai; (2) cer causes OLG depolarization, an effect mimicked by sphingosine-1-phosphate but not by sphingosine; and (3) cer, but not its inactive analog dihydroceramide, inhibits OLG IKir. The cer effect is attenuated by Ras antibody Y13-259, by protein kinase C inhibitory peptide (19-36), and by suppression of c-Raf-1 expression with antisense raf-1 oligonucleotides. We conclude that cer-induced OLG depolarization is mediated via inhibition of IKir by a Ras- and raf-1-dependent pathway, which results in the phosphorylation of the inward rectifier K+ channel protein.     

Limb salvage and survival rates among elderly patients with advanced limb ischemia

Beta-Thalassemia hemoglobin E (beta-thal/Hb E) is the commonest form of hemoglobinopathy in Thailand. Shortened red cell life span, rapid iron turnover and tissue deposition of excess iron are major factors responsible for functional and physiological abnormalities found in various forms of thalassemia. Increased deposition of iron had been found in renal parenchyma of thalassemic patients, but no systematic study of the effect of the deposits on renal functions has been available. The purpose of this study is to describe the functional abnormalities of the kidney in patients with beta-thal/Hb E and provide evidence that increased oxidative stress might be one of the factors responsible for the damage. Urine and serum samples from 95 patients with beta-thal/Hb E were studied comparing with 27 age-matched healthy controls. No difference in the creatinine clearance was observed. beta-thal/Hb E patients excreted significantly more urinary protein (0.8+/-0.5 vs. 0.3+/-0.1 g/day, p < 0.001). Aminoaciduria was found in 16 % of the patients. Analysis of urinary protein by SDS-PAGE electrophoresis and silver staining revealed abnormal pattern of protein with increased small molecular weight (<45 kD) bands. Morning urine analysis showed significant lower urine osmolality (578.3+/-164.6 vs. 762.4+/-169.9 mosm/kg, p < 0.001) in patients. Patients excreted more NAG (N-acetyl beta-D-glucosaminidase, 26.3+/-41.3 vs. 8.4+/-3.9 U/g Cr, p < 0.0001) and beta2-microglobulin, 124.3+/-167 vs. 71+/-65.5 microg/g Cr, p = 0.001. Plasma and urine MDA (malonyldialdehyde) levels were both raised (p < 0.0001). Nine patients were selected for renal acidification study. All were found to be normal, but showed poor response to DDAVP challenge (urine osmolality 533+/-71). This is the first report of renal tubular defects found associated with beta-thal/Hb E disease. The mechanism leading to the damage is not known but it might be related to increased oxidative stress secondary to tissue deposition of iron, as indicated by the raised levels of serum and urine MDA. It is not known whether these functional defects would have any long-term effects on the patients. Further studies are warranted and means of prevention of these defects should urgently be sought.     

A case of neurilemmoma in the infratemporal fossa showing the antral bowing sign

A case is reported of a neurilemmoma which arose in the right infratemporal fossa of a 23-year-old male. A benign tumour was suspected when bowing of the posterior maxillary antral wall was observed on CT.     

High-efficiency power 2DEGFETS based on a surface undoped layer n-AlGaAs/GaAs selectively doped structure for Ka-band

We have evaluated the power performance of surface undoped structure n-AlGaAs/GaAs 2DEGFETs at Ka-band. This unique configuration 2DEGFET with a 0.5 ?m gate length showed a 143 W/mm output power at 28.5 GHz. Furthermore, 7 dB linear gain and 21% power-added efficiency were attained, which are the best data in the Ka-band frequency range reported to date.     

Neuronal damage following transient cerebral ischemia and its restoration by neural transplant

The middle cerebral artery (mca) was intraluminally occluded for one hour prior to reperfusion in the rat. Neuronal damage as well as motor imbalance were assessed in both acute and chronic stages with or without neural transplant in the striatum. In acute stage, argyrophil III staining demonstrated "collapsed" dark neurons in the ipsilateral striatum, cortex, reticular thalamus, amygdala and sometimes in the hippocampus. They had shrunken somata and corkscrew-like dendrites. In accordance with the appearance of dark neurons, the immunoreactivity for calpain of endogenous inactive form decreased or disappeared in ischemic areas. In chronic stage, ischemic core area (striatum and cortex) got into porencephaly, and animals made rotations following methamphetamine injection. Neural transplant (fetal striatal cells) was made during 2 to 4 weeks after the ischemia. Once the transplant survived and grew in the striatum, the methamphetamine rotations were attenuated. Using mca ischemic model rats we report here pathophysiological processes that lead to neuronal damage and infarct. Neural transplants into these animals brought partial restoration in motor disturbance, offering a valuable information concerning therapeutic possibility.     

Internationalization and geographically representative scholarship in journals devoted to behavior analysis: an assessment of 10 journals across 15 years

Scientometrics - There are many reasons to consider behavior analysis an international field. For example, the primary membership organization for the field has affiliated chapters in 33 countries,...     

Moisture-induced drift in thermo-optic phase shifters composed of deuterated and fluorinated methacrylate polymer waveguides

Using deuterated and fluorinated methacrylate polymer waveguides, we fabricated thermo-optic phase shifters that require a small electric power of 10 mW to cause a pi phase shift. The phase shifters had a phase drift that was greater at higher humidity and that was saturated in approximately 10 min. This phenomenon is ascribed to the moisture desorption-sorption of the waveguide polymers caused by heating-cooling on the basis of experimental results on the relationships among waveguide temperature increase, relative humidity, and moisture sorption of the waveguide polymers. This conclusion is supported by the calculation of temperature and moisture distribution in the waveguide when the thin-film heater is heated.