Driven dynamics and rotary echo of a qubit tunably coupled to a harmonic oscillator.

We have investigated the driven dynamics of a superconducting flux qubit that is tunably coupled to a microwave resonator. We find that the qubit experiences an oscillating field mediated by off-resonant driving of the resonator, leading to strong modifications of the qubit Rabi frequency. This opens an additional noise channel, and we find that low-frequency noise in the coupling parameter causes a reduction of the coherence time during driven evolution. The noise can be mitigated with the rotary-echo pulse sequence, which, for driven systems, is analogous to the Hahn-echo sequence.

Silicon waveguide infrared photodiodes with >35 GHz bandwidth and phototransistors with 50 AW-1 response.

SOI CMOS compatible Si waveguide photodetectors are made responsive from 1100 to 1750 nm by Si+ implantation and annealing. Photodiodes have a bandwidth of >35 GHz, an internal quantum efficiency of 0.5 to 10 AW-1, and leakage currents of 0.5 nA to 0.5 microA. Phototransistors have an optical response of 50 AW-1 with a bandwidth of 0.2 GHz. These properties are related to carrier mobilities in the implanted Si waveguide. These detectors exhibit low optical absorption requiring lengths from <0.3 mm to 3 mm to absorb 50% of the incoming light. However, the high bandwidth, high quantum efficiency, low leakage current, and potentially high fabrication yields, make these devices very competitive when compared to other detector technologies.

Low rate of CMV end-organ disease in HIV-infected patients despite low CD4+ cell counts and CMV viremia: results of ACTG protocol A5030.

PURPOSE: To describe cytomegalovirus (CMV) end-organ disease (EOD) rate in AIDS patients with low CD4+ cell count despite HAART who were enrolled in a randomized, placebo-controlled trial of preemptive valganciclovir (VGCV) to prevent CMV EOD in those with CMV viremia. METHODS: Subjects (N = 338) were HIV-infected with CD4+ count <100 cells/mm3, plasma HIV RNA >400 copies/mL, and on stable or no HAART. All underwent plasma CMV DNA PCR testing every 8 weeks (Step 1); those with detectable CMV DNA were randomized to VGCV or placebo (Step 2). RESULTS: Plasma CMV DNA was detected in 68 (20%), of whom 4 developed CMV EOD. During Step 1, 53 died. Of the 47 who entered Step 2 (24 VGCV, 23 placebo), CMV EOD was diagnosed in 10 (4 VGCV, 6 placebo) and 15 died (7 VGCV, 8 placebo). Of those randomized to placebo, 14% were diagnosed with CMV EOD at 12 months. CONCLUSIONS: We observed a lower CMV EOD rate among subjects receiving HAART than predicted based on published literature. However, mortality was high in this study. Our findings suggest that preemptive anti-CMV therapy in patients with persistently low CD4+ cell counts in the current treatment era may not be warranted given the low incidence of CMV EOD and high all-cause mortality observed in this study population.

Disposition of morphine in man.

The disposition of morphine was investigated by means of radioimmunoassay after a single intravenous dose (10 milligrams per 70 kilograms) was administered to 10 adult normal male subjects who had not received other drugs for 2 weeks preceding the study. A multiphasic decline in serum concentrations of morphine occurred. Detectable blood concentrations of morphine, or of a metabolite, or of both persisted for 48 hours after a single intravenous dose.

Evidence for active immunity to morphine in mice.

The serum from mice actively immunized with a morphine immunogen contained antibodies that could bind dihydromorphine. Morphine effects were diminished in these "immunized" mice, and the concentration of morphine in their plasma was altered.

Barbiturates: radioimmunoassay.

The development of a radioimmunoassay for barbiturate is described. The barbiturate is made antigenic by coupling it to a protein, bovine gamma globulin. The radioimmunoassay can measure as little as 5 nanograms of barbiturate.

Morphine: radioimmunoassay.

The development of a radioimmunoassay for morphine is described. The hapten morphine is made antigenic by coupling it to a protein at the phenolic group of the molecule. Extremely low concentrations of morphine (0.5 nanogram) can be measured by this assay procedure.

Serotonin: radioimmunoassay.

The development of a radioimmunoassay for serotonin is described. Serotonin is made antigenic by coupling it to bovine serum albumin. Thrombocyte-free plasma instead of serum from the immunized animals is used for radioimmunoassay. Less than 1 ng serotonin can be measured by this procedure.

A nonpeptide morphine-like compound: immunocytochemical localization in the mouse brain.

A nonpeptide morphine-like compound (MLC) which cross reacts with morphine-specific antibodies has been localized with the use of immunocytochemistry. This morphine-like compound is found in neuronal perikarya or processes (or both) in nuclei related to vestibular, cerebellar, and raphe systems.

Hypertension: increase of collagen biosynthesis in arteries but not in veins.

In two models of hypertension in rats, it was shown that collagen synthesis and deposition are increased in arteries where blood pressure is elevated. By contrast, there were no alterations in any of the markers of collagen synthesis in veins, where blood pressure was only slightly elevated. It would appear that the stimulus for vascular collagen synthesis is provided by a direct effect of the increased pressure on the arterial cells rather than by a humoral factor released into the general circulation.

Vascular smooth muscle reactivity in normotensive and hypertensive rats.

Aortic strips from spontaneously hypertensive rats were less responsive than normal animals to the contractile effects of norepinephrine, serotonin, and potassium chloride but more reactive to the relaxant effects of the stimulant of beta receptors, isoproterenol. Thus, hypertension is not the result of an absence of beta receptor or a hypersensitivity of the vascular smooth muscle.

Human immunodeficiency virus infection of human-PBL-SCID mice.

Severe combined immunodeficient (SCID) mice reconstituted with human peripheral blood leukocytes (hu-PBL-SCID mice) have inducible human immune function and may be useful as a small animal model for acquired immunodeficiency syndrome (AIDS) research. Hu-PBL-SCID mice infected with human immunodeficiency virus-1 (HIV-1) contained virus that was recoverable by culture from the peritoneal cavity, spleen, peripheral blood, and lymph nodes for up to 16 weeks after infection; viral sequences were also detected by in situ hybridization and by amplification with the polymerase chain reaction (PCR). Mice could be infected with multiple strains of HIV-1, including LAV-1/Bru, IIIB, MN, SF2, and SF13. HIV-1 infection affected the concentration of human immunoglobulin and the number of CD4+ T cells in the mice. These results support the use of the hu-PBL-SCID mouse for studies of the pathogenesis and treatment of AIDS.

CMOS-compatible dual-output silicon modulator for analog signal processing.

A broadband, Mach-Zehnder-interferometer based silicon optical modulator is demonstrated, with an electrical bandwidth of 26 GHz and V(pi)L of 4 V.cm. The design of this modulator does not require epitaxial overgrowth and is therefore simpler to fabricate than previous devices with similar performance.

Poor outcome is associated with delayed tuberculosis diagnosis in HIV-infected children in Baja California, Mexico.

OBJECTIVE: To describe the morbidity and mortality associated with tuberculosis (TB) in human immunodeficiency virus (HIV) infected children in Baja California, Mexico. METHODS: Retrospective review of the medical records of all children with perinatally acquired HIV infection evaluated at Tijuana General Hospital with a diagnosis of TB between 1998 and 2007. The Stegen-Toledo (ST) clinical criteria for the diagnosis of TB were used. RESULTS: A total of 73 HIV-infected children were followed during the study period. Thirteen (18%) children were diagnosed with TB; one was confirmed by culture to be positive. Among these children, the mean ages at HIV and TB diagnosis were respectively 3.6 and 5.3 years. The mean ST score was 8.1; 10/13 had a score of >or=7, or highly probable TB. There were a cumulative 29 hospital admissions prior to TB diagnosis; 24 of these were due to pneumonia. The mean duration of symptoms at TB diagnosis was 73 days. The most common symptoms were cough (92%) and anorexia (85%). Seven patients (54%) had disseminated TB and five (39%) died as a consequence of TB. CONCLUSIONS: We observed high morbidity, hospital utilization and high mortality associated with TB among HIV-infected children in Baja California.

Plasma cytomegalovirus (CMV) DNA load predicts CMV disease and survival in AIDS patients.

In this study, baseline plasma from 619 persons with acquired immunodeficiency syndrome (AIDS) (median CD4+ lymphocyte count -21/microl) who participated in a trial to determine the efficacy of oral ganciclovir for cytomegalovirus (CMV) disease prevention were evaluated for CMV DNA load by qualitative and quantitative polymerase chain reaction (PCR), and correlated with the development of CMV disease and survival. For participants without detectable plasma CMV DNA, the 12-mo Kaplan-Meier CMV disease event rate was 14% and 1% for the placebo and ganciclovir groups, respectively (P < 0.001). For PCR positive participants, CMV disease developed in 43% of placebo and 26% ganciclovir recipients (P < 0.017). Among placebo recipients, CMV PCR positivity was associated with a 3.4-fold increased risk of developing CMV disease (P < 0.001) whereas CD4+ lymphocyte count was not a useful predictor (P = 0.47). A positive plasma CMV DNA PCR was also associated with a 2.5-fold increased risk of death. Each log10 increase in baseline CMV DNA load was associated with a 3.1-fold increase in CMV disease (P < 0.001) and a 2.2-fold increase in mortality (P < 0.001). These data indicate that the risk of developing CMV disease and death in persons with advanced AIDS is directly related to the quantity of CMV DNA in plasma, and is a better predictor than CD4+ lymphocyte count in this population.

Mutations in human cytomegalovirus UL97 gene confer clinical resistance to ganciclovir and can be detected directly in patient plasma.

Specific mutations in the UL97 region of human cytomegalovirus (HCMV) have been found to confer resistance to laboratory-adapted strains subjected to ganciclovir selection. In this study, mutations in the UL97 region of HCMV isolates obtained from patients receiving ganciclovir therapy were examined to determine whether they would confer ganciclovir resistance, and if these mutations could be detected directly in the plasma of AIDS patients with progressive HCMV disease despite ganciclovir treatment. A single nucleotide change within a conserved region of UL97 was found in five resistant isolates, resulting in an amino acid substitution in residue 595: from leucine to phenylalanine in one, and from leucine to serine in four resistant isolates. A sixth resistant isolate demonstrated a single nucleotide change, leading to a threonine to isoleucine substitution in residue 659. The role of the 595 amino acid substitution in conferring ganciclovir resistance was confirmed by marker transfer experiments. In further studies, direct sequencing of HCMV DNA present in plasma obtained from persons with resistant viruses revealed the identical amino acid substitutions in plasma as those present in the cultured viruses. These findings indicate that clinical resistance to ganciclovir can result from specific point mutations in the UL97 gene, and that the emergence of the resistant genotype can be detected directly in patient plasma.

All silicon infrared photodiodes: photo response and effects of processing temperature.

CMOS compatible infrared waveguide Si photodiodes are made responsive from 1100 to 1750 nm by Si(+) implantation and annealing. This article compares diodes fabricated using two annealing temperatures, 300 and 475 degrees C. 0.25-mm-long diodes annealed to 300 degrees C have a response to 1539 nm radiation of 0.1 A W-(-1) at a reverse bias of 5 V and 1.2 A W(-1) at 20 V. 3-mm-long diodes processed to 475 degrees C exhibited two states, L1 and L2, with photo responses of 0.3 +/-0.1 A W(-1) at 5 V and 0.7 +/-0.2 A W(-1) at 20 V for the L1 state and 0.5 +/-0.2 A W(-1) at 5 V and 4 to 20 A W(-1)-1 at 20 V for the L2 state. The diodes can be switched between L1 and L2. The bandwidths vary from 10 to 20 GHz. These diodes will generate electrical power from the incident radiation with efficiencies from 4 to 10 %.

Prevalence of primary HIV-1 drug resistance in pregnant women and in newly diagnosed adults at Tijuana General Hospital, Baja California, Mexico.

At Tijuana General Hospital, between March 2003 and June 2005, pregnant women and other adults, recently identified as HIV infected, antiretroviral naïve, were enrolled to examine the prevalence of primary HIV drug resistance. All subjects had the Calypte HIV-1 BED Incidence enzyme immunoassay test to identify recent infection. Genotypic analysis of HIV-1 protease and reverse transcriptase regions in plasma was performed. Forty-six subjects participated, eight (17%) men, 38 (83%) women. Ten (22%) subjects were classified as having recent HIV infection. HIV genotype was performed in 41 subjects. One subject (2.5%) had a major mutation in the reverse transcriptase region (K219Q) conferring zidovudine resistance, one had a minor mutation at V118I (2.5%) and two subjects (5%) had minor mutation (V179D) associated with non-nucleoside reverse transcriptase inhibitor resistance. There were no major protease inhibitor-associated mutations but minor mutations were common. The prevalence of primary HIV drug resistance in Baja California is low.

Performance of rapid HIV testing using Determine HIV-1/2 for the diagnosis of HIV infection during pregnancy in Tijuana, Baja California, Mexico.

The aim of this study was to evaluate the performance of the rapid antibody test Determine HIV-1/2, in pregnant women at Tijuana General Hospital. Pregnant women seeking prenatal care or admitted in labour had blood drawn for a rapid HIV test (Determine HIV-1/2), enzyme immunoassay (EIA) and Western blot. Between March and November 2003, 1068 women in labour and 1529 women in prenatal care were enrolled. The sensitivity, specificity, positive and negative predictive values were 100%, 99.8%, 77% and 100%, respectively. For women in labour, the mean time between blood collection and rapid test results was 92 minutes (range: 20-205 minutes) compared with 41 hours (range 24-120 hours) for HIV EIA (P = 0.012). All HIV-exposed infants received oral zidovudine. These findings indicate that the rapid test Determine HIV-1/2 has a high sensitivity and specificity in pregnant women. Rapid HIV testing greatly diminishes the time to diagnosis and enables prompt intervention with antiretrovirals at delivery.

Is the St. Jude Medical mechanical valve an appropriate choice for elderly patients?: A long-term retrospective study measuring quality of life.

BACKGROUND AND AIM OF THE STUDY: The selection of a suitable valve substitute in patients requiring valvular heart surgery is an important element in the preoperative decision-making process between cardiologist, surgeon, and patient. Controversy persists regarding the use of mechanical valves in the elderly. With the population living longer, reoperative risk becomes of paramount importance. Quality of life (QOL) considerations are often as important to the patient as longevity. The influence of mechanical valve replacement on QOL in elderly patients has not been well documented. METHODS: Between June 1981 and December 1999, a total of 1,125 consecutive patients aged > or = 65 years (582 men, 543 women; mean age 71.4 +/- 4.9 years) underwent valve replacement with at least one St. Jude Medical (SJM) mechanical valve. Preoperatively, 138 patients (12.3%) were in NYHA class II, 775 (68.9%) in class III, and 212 (18.8%) in class IV. In 535 patients (47.6%), coronary artery disease required surgical intervention. Survivors were administered the Short Form (SF)-36 QOL Survey at follow up, which was 96.1% complete. RESULTS: Hospital mortality was 7.6% (85/1,125). Mean follow up was 5.9 years (range: 9 months to 18.4 years). Mean (+/- SEM) actuarial survival was 70.6 +/- 1.4% at five years, and 40.6 +/- 2.0% at 10 years. Male patients scored significantly higher on the SF-36 than controls in physical (p = 0.012) and mental health (p = 0.004). Comparing female patients with controls revealed no significant difference in physical health; however, they scored higher in mental health than controls (p = 0.001). CONCLUSION: The study results clearly demonstrate that heart surgery in the elderly with the SJM mechanical valve can be accomplished with acceptable hospital mortality, morbidity, and excellent long-term results. Moreover, long-term QOL in elderly patients with a SJM valve can be expected to meet or exceed that of age- and gender-matched controls.