Electrically pumped InP-based microdisk lasers integrated with a nanophotonic silicon-on-insulator waveguide circuit

Abstract: We have achieved electrically-injected continuous-wave lasing in InP-based microdisk structures coupled to a sub-micron silicon-on-insulator wire waveguide, fabricated through bonding technology. The threshold current was 0.6 mA with up to 7 µW continuous-wave output power. ©2007 Optical Society of America OCIS codes: (140.5960) Semiconductor lasers; (250.5300) Photonic integrated circuits 1

A hybrid integration strategy for compact, broadband, and highly efficient millimeter-wave on-chip antennas

A novel hybrid integration strategy for compact, broadband, and highly efficient millimeter-wave (mmWave) on-chip antennas is demonstrated by realizing a hybrid on-chip antenna, operating in the [27.5-29.5] GHz band. A cavity-backed stacked patch antenna is implemented on a 600 mu m thick silicon substrate by using air-filled substrate-integrated-waveguide technology. A hybrid on-chip approach is adopted in which the antenna feed and an air-filled cavity are integrated on-chip, and the stacked patch configuration is implemented on a high-frequency printed circuit board (PCB) laminate that supports the chip. A prototype of the hybrid on-chip antenna is validated, demonstrating an impedance bandwidth of 3.7 GHz. In free-space conditions, a boresight gain of 7.3 dBi and a front-to-back ratio of 20.3 dB at 28.5GHz are achieved. Moreover, the antenna is fabricated using standard silicon fabrication techniques and features a total antenna efficiency above 90% in the targeted frequency band of operation. The high performance, in combination with the compact antenna footprint of 0.49 lambda(min) x 0.49 lambda(min), makes it an ideal building block to construct broadband antenna arrays with a broad steering range

Pharmacokinetic and Pharmacodynamic Variability of Fluindione in Octogenarians

In the PREPA observational study, we investigated the factors influencing pharmacokinetic and pharmacodynamic variability in the responses to fluindione, an oral anticoagulant drug, in a general population of octogenarian inpatients. Measurements of fluindione concentrations and international normalized ratio (INR) were obtained for 131 inpatients in whom fluindione treatment was initiated. Treatment was adjusted according to routine clinical practice. The data were analyzed using nonlinear mixed-effects modeling, and the parameters were estimated using MONOLIX 3.2. The pharmacokinetics (PK) of fluindione was monocompartmental, whereas the evolution of INR was modeled in accordance with a turnover model (inhibition of vitamin K recycling). Interindividual variability (IIV) was very large. Clearance decreased with age and with prior administration of cordarone. Patients who had undergone surgery before the study had lower IC50 values, leading to an increased sensitivity to fluindione. Pharmacokinetic exposure is substantially increased in elderly patients, warranting a lower dose of fluindione

Association between the number of coadministered P-glycoprotein inhibitors and serum digoxin levels in patients on therapeutic drug monitoring

BACKGROUND: The ABC transporter P-glycoprotein (P-gp) is recognized as a site for drug-drug interactions and provides a mechanistic explanation for clinically relevant pharmacokinetic interactions with digoxin. The question of whether several P-gp inhibitors may have additive effects has not yet been addressed. METHODS: We evaluated the effects on serum concentrations of digoxin (S-digoxin) in 618 patients undergoing therapeutic drug monitoring. P-gp inhibitors were classified as Class I, with a known effect on digoxin kinetics, or Class II, showing inhibition in vitro but no documented effect on digoxin kinetics in humans. Mean S-digoxin values were compared between groups of patients with different numbers of coadministered P-gp inhibitors by a univariate and a multivariate model, including the potential covariates age, sex, digoxin dose and total number of prescribed drugs. RESULTS: A large proportion (47%) of the digoxin patients undergoing therapeutic drug monitoring had one or more P-gp inhibitor prescribed. In both univariate and multivariate analysis, S-digoxin increased in a stepwise fashion according to the number of coadministered P-gp inhibitors (all P values < 0.01 compared with no P-gp inhibitor). In multivariate analysis, S-digoxin levels were 1.26 ± 0.04, 1.51 ± 0.05, 1.59 ± 0.08 and 2.00 ± 0.25 nmol/L for zero, one, two and three P-gp inhibitors, respectively. The results were even more pronounced when we analyzed only Class I P-gp inhibitors (1.65 ± 0.07 for one and 1.83 ± 0.07 nmol/L for two). CONCLUSIONS: Polypharmacy may lead to multiple drug-drug interactions at the same site, in this case P-gp. The S-digoxin levels increased in a stepwise fashion with an increasing number of coadministered P-gp inhibitors in patients taking P-gp inhibitors and digoxin concomitantly. As coadministration of digoxin and P-gp inhibitors is common, it is important to increase awareness about P-gp interactions among prescribing clinicians

Comparison of On-Track and Not-On-Track Senior High School Students: An Assessment of Student Needs and Social Characteristics

The student dropout dilemma in the American educational system has remained unchanged for the past 30 years. Dropout figures show more than 6 million high school dropouts living in the United States today. The purpose of this study was to compare and analyze potential dropout variables between two groups of senior students at a local high school. This study included 228 senior students who were identified within two groups: on-track for graduation and not-on-track for graduation based on state exit exam results. A student questionnaire and student records were used to gather data. The study included descriptive, multivariate, and analysis of variance to determine the relationship of variables between the two groups that may lead to increased probability of students belonging to either group. Findings from the study suggested the following: 1.Not-on-track students desired more assistance from their school in educational development and planning. 2.On-track students had higher mean averages in academic scores. 3.Not-on-track students had fewer mothers, more children, and more adults living in the family home and were less represented in extracurricular activities. 4.Not-on-track students endorsed more negative responses about themselves. Research suggests that state exit exam requirements for graduation most likely do not cause additional student dropouts; however, research shows that exit exams may be the tipping factor for many students to ultimately drop out. Thus, exit exams can possibly increase student dropouts. The not-on-track students in this study may be at their tipping point. The results from this study show on-track students have fewer dropout factors within their group and higher academic averages than students in the not-on-track group. The following recommendations are based on the study: 1. Further research should be conducted that uses a student need's assessment instrument but includes former students who dropped out. 2. A study that concentrates on student's feelings of their school should be conducted at the middle school grade levels. 3. A study comparing responses of students versus responses of teachers could shine light on the school environment

Apolipoprotein AI transgene corrects apolipoprotein E deficiency-induced atherosclerosis in mice.

Apolipoprotein E (apo E)-deficient mice are severely hypercholesterolemic and develop advanced atheromas independent of diet. The C57BL/6 strain differs from most inbred strains by having lower HDL concentrations and a high risk of developing early atherosclerotic lesions when fed an atherogenic diet. The relative HDL deficiency and atherosclerosis susceptibility of the C57BL/6 strain are corrected with the expression of a human apolipoprotein AI (apo AI) transgene in this genetic background. To examine if increases in apo AI and HDL are also effective in minimizing apo E deficiency--induced atherosclerosis, we introduced the human apo AI transgene into the hypercholesterolemic apo E knockout background. Similar elevations of total plasma cholesterol occurred in both the apo E knockout and apo E knockout mice also expressing the human apo AI transgene. The latter animals, however, also showed a two- to threefold increase in HDL and a sixfold decrease in susceptibility to atherosclerosis. This study demonstrates that elevating the concentration of apo AI reduces atherosclerosis in apo E deficient-mice and suggests that elevation of apo AI and HDL may prove to be a useful approach for treating unrelated causes of heightened atherosclerosis susceptibility