Si photonic-electronic monolithically integrated optical receiver with a built-in temperature-controlled wavelength filter.

We present a Si photonic-electronic integrated ring-resonator based optical receiver that contains a temperature-controlled ring-resonator filter (RRF), a Ge photodetector, and receiver circuits in a single chip. The temperature controller automatically determines the RRF temperature at which the maximum transmission of the desired WDM signal is achieved and maintains this condition against any temperature or input wavelength fluctuation. This Si photonic-electronic integrated circuit is realized with 0.25-µm photonic BiCMOS technology, and its operation is successfully confirmed with measurement.

High bandwidth, high responsivity waveguide-coupled germanium p-i-n photodiode.

A novel waveguide-coupled germanium p-i-n photodiode is demonstrated which combines high responsivity with very high -3 dB bandwidth at a medium dark current. Bandwidth values are 40 GHz at zero bias and more than 70 GHz at -1 V. Responsivity at 1.55 µm wavelength ranges from 0.84 A/W at zero bias to 1 A/W at -1 V. Room temperature dark current density at -1 V is about 1 A/cm2. The high responsivity mainly results from the use of a new, low-loss contact scheme, which moreover also reduces the negative effect of photo carrier diffusion on bandwidth.

Gender related differences in predictors of vascular complications: role of vessel size and BMI.

Women undergoing cardiac catheterization have an increased risk of vascular complications (VC) compared to men. Whether this is due to gender differences in common femoral artery (CFA) anatomy remains unknown. Therefore, we examined angiographic features of CFA to identify differences in predictors of VC between the genders. A case control study design enrolled 59 (30 women and 29 men) consecutive patients with VC and 59 age, gender and procedure matched controls from 2004 to 2009. VC were defined as hematoma >6 cm, any access site related bleeding requiring transfusion or injury requiring mechanical intervention. Quantitative angiography was performed on all femoral angiograms. Univariate and multivariate regression was performed to define clinical and angiographic predictors of VC. Among all patients, cases had significantly lower BMI than controls (28.4 ± 7.7 vs. 32.0 ± 6.7, p ≤ 0.01) and were more than twice likely to have CFA reference vessel diameter <5.5 mm (p = 0.04). This finding was entirely driven by the inverse relationship between BMI, CFA and VC among women. On multivariate analysis, BMI was a potent predictor of VC (OR 0.94; 95 % CI 0.89-0.99; p = 0.04). When comparing men and women, BMI and CFA size were predictors of VC among women only. Among men, site of arteriotomy and diabetes mellitus predicted risk of VC. Smaller BMI correlates with smaller CFA diameter and both are predictive of increased risk of VC. This may explain the female predisposition to VC. Risk stratification for bleeding and VC should address these gender specific findings.

Toward coherent O-band data center interconnects.

Upcoming generations of coherent intra/inter data center interconnects currently lack a clear path toward a reduction of cost and power consumption, which are the driving factors for these data links. In this work, the tradeoffs associated with a transition from coherent C-band to O-band silicon photonics are addressed and evaluated. The discussion includes the fundamental components of coherent data links, namely the optical components, fiber link and transceivers. As a major component of these links, a monolithic silicon photonic BiCMOS O-band coherent receiver is evaluated for its potential performance and compared to an analogous C-band device.

Recent developments in the use of antiplatelet agents to prevent cardiovascular events.

Platelets are pivotal contributors to arterial thrombosis. Dual antiplatelet therapy with aspirin and clopidogrel has become the standard of care for the secondary prevention of cardiovascular events in patients with acute coronary syndromes and after percutaneous coronary intervention. Clinical evidence of the continued risk of cardiovascular events plus pharmacodynamic evidence of substantial variability in on-treatment platelet reactivity has supported the development of new therapeutic strategies, using established agents and new antiplatelet drugs. This article will highlight recent pivotal clinical trials seeking to advance the use of antiplatelet therapy in patients with cardiovascular disease.

The effect of weight loss and exercise training on flow-mediated dilatation in coronary heart disease: a randomized trial.

BACKGROUND: More than 80% of patients entering cardiac rehabilitation are overweight, with a high prevalence of associated insulin resistance, diabetes, hypertension, hyperlipidemia, and a prothrombotic state. Because each of these characteristics is associated with abnormalities of endothelial-dependent flow-mediated dilatation (FMD), a predictor of long-term prognosis in patients with coronary heart disease (CHD), we assessed the effect of exercise training and weight reduction on FMD in overweight patients with CHD. METHODS: All patients (N = 38) participated in behavioral weight loss while taking their usual preventive medications. Subjects were randomized to one of two exercise protocols, which differed by caloric expenditure. The primary outcome was extent (%) of brachial artery FMD measured by ultrasonography before and after the 4-month exercise and weight-loss program. RESULTS: Both study groups experienced an increase in brachial artery FMD after weight loss and exercise. Patients randomized to the higher-caloric exercise condition (longer-distance walking) lost more weight (8.6 ± 4.1 kg vs 2.3 ± 3.3 kg [P < .001]) and experienced a greater percentage increase in brachial artery FMD (3.6% ± 4.1% vs 1.3% ± 2.1%, P < .05) than did subjects in the lower-caloric-expenditure exercise group who lost less weight. Both groups increased peak aerobic capacity similarly. Increased FMD correlated with changes in body weight more than with measures of abdominal fat, glucose disposal, lipid measure, BP, or measures of physical activity or cardiorespiratory fitness. CONCLUSIONS: Exercise and weight loss increased FMD in overweight and obese patients with CHD. Greater weight reduction was associated with a greater improvement in FMD; thus, there was a dose effect. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00628277; URL: www.clinicaltrials.gov.

Angiographic predictors of vascular complications among women undergoing cardiac catheterization and intervention.

BACKGROUND: Bleeding and vascular complications remain more common in women than men undergoing invasive cardiovascular procedures. We determined the role of femoral angiographic variables in risk-stratifying women for vascular complications. METHODS: Between 2004-2009, all major bleeding and vascular complications among women undergoing diagnostic or interventional cardiovascular procedures were identified at a single center. Thirty consecutive female patients (major bleeding or vascular complication) were then age- and procedure-matched to 90 controls (no vascular complications). Quantitative femoral angiography was performed on all cases and controls. RESULTS: Smaller minimum luminal diameter was a strong univariate predictor of vascular complications in women (odds ratio [OR] 0.65; 95% confidence interval [CI] 0.47-0.90; p = 0.009), while site of arteriotomy was not predictive of complications. The prognostic significance of smaller femoral lumen diameter was mildly attenuated after adjusting for the predictive factor of smaller patient body size, even after adjusting for the predictive factor of smaller patient body size. Finally, multivariable modeling suggests that utilization of vascular closure devices (OR 0.26, 95% CI 0.07-0.96; p = 0.04) may be protective in women. CONCLUSIONS: Women with smaller femoral arteries are at significantly higher risk for bleeding and vascular complications than women with larger femoral arteries. Risk stratification for bleeding complications among women should account for clinical, pharmacologic and femoral angiographic factors.

Recurrent left ventricular apical ballooning induced by recurrent stress.

This paper reports on a 67-year-old woman with apical ballooning and recurrent dyskinesia of left ventricular wall. During MRI-examination the patient developed severe apical dyskinesia of the left ventricle induced by agoraphobia in the magnet.

Consistent door-to-balloon times of less than 90 minutes for STEMI patients transferred for primary PCI.

BACKGROUND: Recent data from large national registries show that < 15% of patients with ST-elevation myocardial infarction (STEMI) transferred for primary percutaneous intervention (PCI) actually meet the door-to-balloon (D2B) goal of < or = 90 minutes, and only onethird achieve D2B times of < or = 120 minutes. We established a streamlined STEMI protocol to allow rapid transfer of STEMI patients for primary PCI to meet the ACC D2B goal of < or = 90 minutes in at least 75% of the patients. METHODS: From February 2007 to August 2008, 37 consecutive patients presenting with STEMI to a community hospital in Vermont were transferred 26 miles to the University of Vermont (UVM) for primary PCI. Three time intervals were evaluated: presentation to departure time at the referring hospital, transfer time and UVM PCI time (time from arrival to the cath lab to balloon time). Total D2B time was defined as presentation to the first hospital to first balloon inflation. RESULTS: The majority of transfers (69%) occurred off-hours. All patients received aspirin and clopidogrel and heparin pre-PCI. Median presentation to departure time at the STEMI referral hospital, total transfer and UVM PCI times were 26 (20, 33), 36 (34, 40) and 20 (16, 22) minutes, respectively. The median D2B time was 82 (77, 91) minutes, with 73% of patients achieving the goal D2B of < or = 90 minutes, and 94% achieving a D2B time of < or = 120 minutes. CONCLUSION: For patients in a rural setting who present with STEMI, transfer of approximately 30 miles for timely primary PCI can be achieved in nearly 75% of patients using a simplified streamlined protocol.