A CMOS multichannel 10-Gb/s transceiver

We describe a CMOS multichannel transceiver that transmits and receives 10 Gb/s per channel over balanced copper media. The transceiver consists of two identical 10-Gb/s modules. Each module operates off a single 1.2-V supply and has a single 5-GHz phase-locked loop to supply a reference clock to two transmitter (Tx) channels and two receiver (Rx) channels. To track the input-signal phase, the Rx channel has a clock recovery unit (CRU), which uses a phase-interpolator-based timing generator and digital loop filter. The CRU can adjust the recovered clock phase with a resolution of 1.56 ps. Two sets of two-channel transceiver units were fabricated in 0.11-/spl mu/m CMOS on a single test chip. The transceiver unit size was 1.6 mm /spl times/ 2.6 mm. The Rx sensitivity was 120-mVp-p differential with a 70-ps phase margin for a common-mode voltage ranging from 0.6 to 1.0 V. The evaluated jitter tolerance curve met the OC-192 specification.     

Effects of changes in head and neck position on a tracheal tube cuff

Thirteen patients were intubated with cuffed reinforced spiral tracheal tubes. Intracuff pressure and volume were measured as the position of the head and neck was altered. No significant changes in intracuff pressure and volume were observed with lateral rotation of the head. A significant increase in intracuff pressure was observed and excessive pressure (> 25 cm H2O) developed in 8 patients with head and neck flexion. A significant decrease of intracuff pressure and air-leak were observed in 9 patients with extension. Reinflated intracuff volume decreased and reinflated intracuff pressure increased significantly, and residual excessive pressure was observed in 4 patients with flexion. Both reinflated intracuff volume and pressure increased significantly, and excessive pressure was observed in 8 patients and residual air-leak developed in a patient in spite of excessive pressure with extension. The authors speculate that endotracheal tube movement by changes in head and neck position has effects on intracuff pressure and volume.     

A pulse-based, parallel-element macromodel for ferroelectric capacitors

A pulse-based behavioral model is proposed and implemented in HSPICE. Hysteresis-loop and pulse measurement results are used to extract the model parameters. The model accurately predicts the bitline voltage of a ferroelectric memory testchip.     

Hydrogen embrittlement susceptibility of microstructures formed in multipass weld metal for HT780 class steel

The effect of reheating by following passes on the hydrogen embrittlement of MAG weld metal for HT780 class steels has been investigated by using specimens subjected to simulated thermal cycles. The hydrogen-charged specimens exhibited transgranular quasi-cleavage fracture and intergranular fracture along prior austenite grain boundaries on slow strain rate tensile (SSRT) tests, depending on the reheated temperature and charged hydrogen content. The reduction in elongation of hydrogen-charged specimens became more significant when intergranular fracture occurred. When specimens in as-welded state and precedently reheated at coarse grained HAZ temperature of 1,623 K were reheated at a tempering temperature of 873 K, significant amount of intergranular fracture occurred at charged hydrogen contents above 3 ppm in spite of the decrease in hardness. The specimen reheated at 1,173 K showed no intergranular fracture even after receiving the reheating at 873 K at a hydrogen content of 6 ppm, suggesting the strong influence of the prior austenite grain size on the hydrogen-induced intergranular embrittlement. The measurement of hydrogen content desorbed from the hydrogen-charged specimen at room temperature suggested that the intergranular fracture caused by the reheating at 873 K was associated with an increase in susceptibility to hydrogen embrittlement of the prior austenite grain boundary itself rather than a decrease in the amounts of trapping sites such as dislocation and retained austenite.     

A 5-6.4-Gb/s 12-channel transceiver with pre-emphasis and equalization

A 5-6.4 Gb/s transceiver, consisting of a parallel 12-channel transmitter (Tx), 12-channel receiver (Rx), clock generators based on LC-VCO phase-locked loops (PLLs), and a clock recovery unit, was developed. The Tx has a five-tap pre-emphasis filter, and the Rx has an equalizer with an intersymbol interference (ISI) monitor. Monitoring the ISI enables fine adjustment of loss compensation. The pre-emphasis filter in the Tx and the equalizer in the Rx compensate for transmission losses of up to 20 dB at 6.4 Gb/s, respectively. Both the Tx and Rx channels, including the PLLs, are 3.92 mm/sup 2/ in area. The transmitter dissipates 150 mW/channel at 6.4 Gb/s when compensating for a loss of 20 dB, and the receiver 90 mW/channel when compensating for the same loss.     

Differential effect of interleukin 10 on interleukin 12- and interleukin 2-mediated killer induction from blood mononuclear cells

Symptomatic tarsal coalition is often considered to be synonymous with peroneal spastic flatfoot. The association of the cavovarus foot type with tarsal coalition is less well established and has been described only in children. This article describes a case of an adult female with symptomatic cavovarus feet with talocalcaneal coalition. The authors theorize about the pathology of muscle spasm and pain in patients with this condition.     

omega-Conotoxin GVIA and desipramine insensitive norepinephrine efflux from cardiac sympathetic nerve terminal

Magnesium is important in cerebral function. If there is a deficiency and neurological symptoms accrue, we hypothesised that Mg2+ deficiency causes neurological symptoms by decreasing the level of Mg2+ in cerebral tissue. The content of magnesium was determined in 12 brain structures in magnesium-deficient rats. Experiments were carried out for 40 days in two groups of Wistar male rats made magnesium-deficient (MD) by a well-controlled diet (50 mg of Mg2+/kg of food), and a control group (CG) rats fed normal diet (1 g of Mg2+/kg of food). At the end of the 40 days, the clinical signs of hypomagnesemia were sought in the MD rats and Mg2+ concentration levels were measured in the blood and brain. The results showed variable distribution of Mg2+ in the different brain structures, both in CG and MD rats; in the MD rats there is an important stability of global Mg2+ content of the brain. Although the global values for Mg2+ in the brain did not decline in MD rats, there was a significant decrease in Mg2+ in the brainstem. We conclude that the brain is able to maintain a stable concentration of Mg2+ during chronic hypomagnesemia, but its topographic variations could account for some of neurological signs accompanying this condition.     

Parallel voltage sag compensator with reduced capacitance using a boost‐type power factor correction rectifier

A new circuit of parallel‐type voltage sag compensator is proposed in this paper. The proposed voltage sag compensator can reduce the necessary capacity of the energy storage capacitor for compensation by boost‐type power factor correction rectifier charging the capacitor during a voltage sag. As a result the proposed system can reduce the size and maintenance of the apparatus. Copyright © 2004 Wiley Periodicals, Inc. This paper shows the principle and control system of the proposed circuit. Compensation characteristics were demonstrated by simulation and experiment. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(2): 19–33, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20261     

Increasing the current density of dielectric-base transistors withan MgO emitter-base barrier

We measured the current-voltage characteristics of YBa₂Cu₃O_7-x/oxide/n-SrTiO₃ diodes using NdGaO₃, LaAlO₃, CeO₂, and MgO as the oxide. MgO films had the highest current density. We then fabricated dielectric-base transistors with a YBa₂Cu₃ O_7-x(YBCO) emitter/collector on a SrTiO₃ dielectric base with an MgO barrier. The transistors had both voltage and current gains exceeding unity at 4.2 K. The emitter current density was about 4×10³ A/cm² at a collector-emitter voltage of 10 V and base-emitter voltage 10 V; this is 2 to 3 orders of magnitude larger than that of transistors with NdGaO₃ emitter-base barrier. We obtained a transconductance of around 0.4 mS at a collector-emitter voltage of 10 V for a device with a 6-μm-diameter emitter     

Norepinephrine efflux evoked by potassium chloride in cat sympathetic nerves: dual mechanism of action

Azithromycin prevents malaria in animal models and early clinical trials. We determined the prophylactic efficacy of three antibiotic regimens given for 10 weeks (azithromycin, 250 mg daily; azithromycin, 1,000 mg weekly; and doxycycline, 100 mg daily) relative to that of placebo for 232 adult volunteers residing in an area of intense malaria transmission. Any confirmed parasitemia during the study was considered a prophylactic failure. Two hundred thirteen volunteers (92%) completed the study. The prophylactic efficacies were as follows: daily azithromycin, 82.7% (95% confidence interval [CI], 68.5%-91.1%); weekly azithromycin, 64.2% (95% CI, 47.1%-77.1%); and daily doxycycline, 92.6% (95% CI, 79.9%-97.5%). All regimens were well tolerated. We concluded that both 100 mg of doxycycline and 250 mg of azithromycin, given daily, were effective as prophylaxis for malaria in this setting. If studies with nonimmune volunteers confirm these results for semi-immune volunteers, a daily azithromycin regimen may have special utility for individuals with contraindications to treatment with doxycycline or other antimalarial agents.