Apollo Photovoltaic Overview and Assessment

This senior project aims to take the various data sheets provided to us by PIVVIR Solar, the organization in charge of Apollo photovoltaic power plant, and perform an overall assessment as well as condensing the information into a more digestible and concise document. Currently, the documents provided to us by PIVVIR Solar are scattered and disorganized. Our goal is to take what we understand about photovoltaic power plants and combine it with the Apollo plant’s datasheets and summarize everything into one focused document that more readers can understand

Serum proteins and paraproteins in women with silicone implants and connective tissue disease: a case–control study

Prior studies have suggested abnormalities of serum proteins, including paraproteins, in women with silicone implants but did not control for the presence of connective-tissue disease (CTD). This retrospective case–control study, performed in tertiary-care academic centers, assessed possible alterations of serum proteins, including paraproteins, in such a population. Seventy-four women with silicone implants who subsequently developed CTD, and 74 age-matched and CTD-matched women without silicone implants, were assessed in the primary study; other groups were used for additional comparisons. Routine serum protein determinations and high-sensitivity protein electrophoresis and immunofixation electrophoresis were performed for detection of paraproteins. Women with silicone implants, either with or without CTD, had significantly lower serum total protein and α1-globulin, α2-globulin, β-globulin, γ-globulin, and IgG levels compared with those without silicone implants. There was no significant difference, however, in the frequency of paraproteinemia between women with silicone implants and CTD (9.5%) and age-matched and CTD-matched women without silicone implants (5.4%) (odds ratio, 1.82; 95% confidence interval, 0.51–6.45). Paraprotein isotypes were similar in the two groups, and the clinical characteristics of the 13 women with paraproteinemia were comparable with an independent population of 10 women with silicone breast implants, CTD, and previously diagnosed monoclonal gammopathies. In summary, this first comprehensive study of serum proteins in women with silicone implants and CTD found no substantially increased risk of monoclonal gammopathy. Women with silicone implants, however, had unexpectedly low serum globulin and immunoglobulin levels, with or without the subsequent development of CTD. The causes and clinical implications of these findings require further investigation

Chalcogen-hyperdoped germanium for short-wavelength infrared photodetection

Obtaining short-wavelength-infrared (SWIR; 1.4 μm–3.0 μm) room-temperature photodetection in a low-cost, group IV semiconductor is desirable for numerous applications. We demonstrate a non-equilibrium method for hyperdoping germanium with selenium or tellurium for dopant-mediated SWIR photodetection. By ion-implanting Se or Te into Ge wafers and restoring crystallinity with pulsed laser melting induced rapid solidification, we obtain single crystalline materials with peak Se and Te concentrations of 1020 cm−3 (104 times the solubility limits). These hyperdoped materials exhibit sub-bandgap absorption of light up to wavelengths of at least 3.0 μm, with their sub-bandgap optical absorption coefficients comparable to those of commercial SWIR photodetection materials. Although previous studies of Ge-based photodetectors have reported a sub-bandgap optoelectronic response only at low temperature, we report room-temperature sub-bandgap SWIR photodetection at wavelengths as long as 3.0 μm from rudimentary hyperdoped Ge:Se and Ge:Te photodetectors

Evolution of the Color-Magnitude Relation in Galaxy Clusters at z ~1 from the ACS Intermediate Redshift Cluster Survey

We apply detailed observations of the Color-Magnitude Relation (CMR) with the ACS/HST to study galaxy evolution in eight clusters at z~1. The early-type red sequence is well defined and elliptical and lenticular galaxies lie on similar CMRs. We analyze CMR parameters as a function of redshift, galaxy properties and cluster mass. For bright galaxies (M_B < -21mag), the CMR scatter of the elliptical population in cluster cores is smaller than that of the S0 population, although the two become similar at faint magnitudes. While the bright S0 population consistently shows larger scatter than the ellipticals, the scatter of the latter increases in the peripheral cluster regions. If we interpret these results as due to age differences, bright elliptical galaxies in cluster cores are on average older than S0 galaxies and peripheral elliptical galaxies (by about 0.5Gyr). CMR zero point, slope, and scatter in the (U-B)_z=0 rest-frame show no significant evolution out to redshift z~1.3 nor significant dependence on cluster mass. Two of our clusters display CMR zero points that are redder (by ~2sigma) than the average (U-B)_z=0 of our sample. We also analyze the fraction of morphological early-type and late-type galaxies on the red sequence. We find that, while in the majority of the clusters most (80% to 90%) of the CMR population is composed of early-type galaxies, in the highest redshift, low mass cluster of our sample, the CMR late-type/early-type fractions are similar (~50%), with most of the late-type population composed of galaxies classified as S0/a. This trend is not correlated with the cluster's X-ray luminosity, nor with its velocity dispersion, and could be a real evolution with redshift.Comment: ApJ, in press, 27 pages, 22 figure

Microbial synthesis of core/shell gold/palladium nanoparticles for applications in green chemistry

We report a novel biochemical method based on the sacrificial hydrogen strategy to synthesize bimetallic gold (Au)–palladium (Pd) nanoparticles (NPs) with a core/shell configuration. The ability of Escherichia coli cells supplied with H2 as electron donor to rapidly precipitate Pd(II) ions from solution is used to promote the reduction of soluble Au(III). Pre-coating cells with Pd(0) (bioPd) dramatically accelerated Au(III) reduction, with the Au(III) reduction rate being dependent upon the initial Pd loading by mass on the cells. Following Au(III) addition, the bioPd–Au(III) mixture rapidly turned purple, indicating the formation of colloidal gold. Mapping of bio-NPs by energy dispersive X-ray microanalysis suggested Au-dense core regions and peripheral Pd but only Au was detected by X-ray diffraction (XRD) analysis. However, surface analysis of cleaned NPs by cyclic voltammetry revealed large Pd surface sites, suggesting, since XRD shows no crystalline Pd component, that layers of Pd atoms surround Au NPs. Characterization of the bimetallic particles using X-ray absorption spectroscopy confirmed the existence of Au-rich core and Pd-rich shell type bimetallic biogenic NPs. These showed comparable catalytic activity to chemical counterparts with respect to the oxidation of benzyl alcohol, in air, and at a low temperature (90°C)

Optical tweezers for the study of microbubble dynamics in ultrasound

2005/2006Optical tweezers enable for non-destructive, contact-free manipulation of ultrasound contrast agent (UCA) microbubbles, which are used in medical imaging for enhancing the echogenicity of the blood pool and to quantify organ perfusion. Understanding the dynamics of ultrasound-driven contrast agent microbubbles from a fundamental physical standpoint is a first step for exploiting their acoustical properties and to develop new diagnostic and therapeutic applications. However, experiments on bubble dynamics presently suffer from a lack of control on bubble position, because of buoyancy, microstreaming and bubble clustering. In this respect, optical tweezers can be used to study UCA microbubbles under controlled and repeatable conditions, by positioning them away from interfaces and from neighboring bubbles. In addition, an ultra-high speed imaging system is required to record the dynamics of UCA microbubbles in ultrasound, as their oscillations occur on the nanoseconds timescale. In this thesis, optical tweezers and an ultra-high speed camera are integrated into an experimental setup to control the boundary conditions and record the oscillations of the microbubbles. Optical tweezers are commonly obtained by focusing a laser beam through a microscope objective, as the high intensity gradient in the focal region causes dielectric microparticles to be attracted in the focus. In the special case of microbubbles, which exhibit a lower refractive index than the surrounding liquid, the opposite situation arises: they are pushed away from the region of maximum intensity. Nevertheless, microbubbles can be trapped in the dark core of a donut-shaped trap, which can be obtained e.g. by focusing a Laguerre-Gaussian beam. In our setup, a Gaussian beam is converted to a Laguerre-Gaussian mode by using diffractive optical elements implemented on a spatial light modulator. This allows to trap and manipulate single or multiple microbubbles, and to control the distance from interfaces as well as the bubbleto- bubble distance. The “Brandaris 128” ultra-high speed camera is used, in combination with the optical tweezers, to recorded the bubble oscillations at a frame rate of 15 million frames per second. The influence of a rigid wall on the resonance frequency and oscillation amplitude was experimentally investigated. An experimental phospholipid-coated agent (BR-14, Bracco Research S.A., Geneva, Switzerland) was used throughout the experiments. A resonance frequency curve was recorded for the same bubble positioned at the wall and at controlled distance from the wall. The experiments show a drop in the resonance frequency for the bubble close to the ii Abstract wall, as expected from the theoretical models. These results are highly relevant for molecular imaging applications, where the response of targeted microbubbles needs to be discriminated from that of freely flowing ones. We also quantify the bubble-to-bubble interaction, in two ways: first, we compare the change of the radial oscillations of one bubble with and without a neighboring bubble. Second, we resolve the change in distance between two bubbles during ultrasonic insonation. This results from an acoustical, generally attractive, interaction force between the bubbles, termed secondary Bjerknes force. To understand this rich two-bubble dynamics, we couple a recent single-bubble model, accounting for both gas and monolayer properties with a model quantifying the mutual interaction of bubbles in their translation and oscillations. Experiments where optical tweezers are used as a force sensor to measure the binding force in an antigen-antibody complex at the single molecule level are also presented. In the future, the possibility of combining optical micromanipulation with the force-sensing capabilities of optical tweezers will open the way to a new class of experiments which will give us a deeper insight into fundamental bubble phenomena and find direct application to new ultrasound-assisted targeting strategies.XIX Ciclo197

Combination Antifungal Therapy for Cryptococcal Meningitis

Background Combination antifungal therapy (amphotericin B deoxycholate and flucytosine) is the recommended treatment for cryptococcal meningitis but has not been shown to reduce mortality, as compared with amphotericin B alone. We performed a randomized, controlled trial to determine whether combining flucytosine or high-dose fluconazole with high-dose amphotericin B improved survival at 14 and 70 days. Methods We conducted a randomized, three-group, open-label trial of induction therapy for cryptococcal meningitis in patients with human immunodeficiency virus infection. All patients received amphotericin B at a dose of 1 mg per kilogram of body weight per day; patients in group 1 were treated for 4 weeks, and those in groups 2 and 3 for 2 weeks. Patients in group 2 concurrently received flucytosine at a dose of 100 mg per kilogram per day for 2 weeks, and those in group 3 concurrently received fluconazole at a dose of 400 mg twice daily for 2 weeks. Results A total of 299 patients were enrolled. Fewer deaths occurred by days 14 and 70 among patients receiving amphotericin B and flucytosine than among those receiving amphotericin B alone (15 vs. 25 deaths by day 14; hazard ratio, 0.57; 95% confidence interval [CI], 0.30 to 1.08; unadjusted P=0.08; and 30 vs. 44 deaths by day 70; hazard ratio, 0.61; 95% CI, 0.39 to 0.97; unadjusted P=0.04). Combination therapy with fluconazole had no significant effect on survival, as compared with monotherapy (hazard ratio for death by 14 days, 0.78; 95% CI, 0.44 to 1.41; P=0.42; hazard ratio for death by 70 days, 0.71; 95% CI, 0.45 to 1.11; P=0.13). Amphotericin B plus flucytosine was associated with significantly increased rates of yeast clearance from cerebrospinal fluid (−0.42 log10 colony-forming units [CFU] per milliliter per day vs. −0.31 and −0.32 log10 CFU per milliliter per day in groups 1 and 3, respectively; P<0.001 for both comparisons). Rates of adverse events were similar in all groups, although neutropenia was more frequent in patients receiving a combination therapy. Conclusions Amphotericin B plus flucytosine, as compared with amphotericin B alone, is associated with improved survival among patients with cryptococcal meningitis. A survival benefit of amphotericin B plus fluconazole was not found

Local Delivery of Interleukin 4 by Retrovirus-Transduced T Lymphocytes Ameliorates Experimental Autoimmune Encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory autoimmune disease of the central nervous system which serves as a model for the human disease multiple sclerosis. We demonstrate here that encephalitogenic T cells, transduced with a retroviral gene, construct to express interleukin 4, and can delay the onset and reduce the severity of EAE when adoptively transferred to myelin basic protein–immunized mice. Thus, T lymphocytes transduced with retroviral vectors can deliver “regulatory cytokines” in a site-specific manner and may represent a viable therapeutic strategy for the treatment of autoimmune disease