32 research outputs found
Cold-Adapted Influenza and Recombinant Adenovirus Vaccines Induce Cross-Protective Immunity against pH1N1 Challenge in Mice
The rapid spread of the 2009 H1N1 pandemic influenza virus (pH1N1) highlighted problems associated with relying on strain-matched vaccines. A lengthy process of strain identification, manufacture, and testing is required for current strain-matched vaccines and delays vaccine availability. Vaccines inducing immunity to conserved viral proteins could be manufactured and tested in advance and provide cross-protection against novel influenza viruses until strain-matched vaccines became available. Here we test two prototype vaccines for cross-protection against the recent pandemic virus.BALB/c and C57BL/6 mice were intranasally immunized with a single dose of cold-adapted (ca) influenza viruses from 1977 or recombinant adenoviruses (rAd) expressing 1934 nucleoprotein (NP) and consensus matrix 2 (M2) (NP+M2-rAd). Antibodies against the M2 ectodomain (M2e) were seen in NP+M2-rAd immunized BALB/c but not C57BL/6 mice, and cross-reacted with pH1N1 M2e. The ca-immunized mice did not develop antibodies against M2e. Despite sequence differences between vaccine and challenge virus NP and M2e epitopes, extensive cross-reactivity of lung T cells with pH1N1 peptides was detected following immunization. Both ca and NP+M2-rAd immunization protected BALB/c and C57BL/6 mice against challenge with a mouse-adapted pH1N1 virus.Cross-protective vaccines such as NP+M2-rAd and ca virus are effective against pH1N1 challenge within 3 weeks of immunization. Protection was not dependent on recognition of the highly variable external viral proteins and could be achieved with a single vaccine dose. The rAd vaccine was superior to the ca vaccine by certain measures, justifying continued investigation of this experimental vaccine even though ca vaccine is already available. This study highlights the potential for cross-protective vaccines as a public health option early in an influenza pandemic
Lifetime body size and reproductive factors: comparisons of data recorded prospectively with self reports in middle age
<p>Abstract</p> <p>Background</p> <p>Data on lifetime exposures are often self-reported in epidemiologic studies, sometimes many years after the relevant age. Validity of self-reported data is usually inferred from their agreement with measured values, but few studies directly quantify the likely effects of reporting errors in body size and reproductive history variables on estimates of disease-exposure associations.</p> <p>Methods</p> <p>The MRC National Survey of Health and Development (NSHD) and the Million Women Study (MWS) are UK population-based prospective cohorts. The NSHD recruited participants at birth in 1946 and has followed them at regular intervals since then, whereas the MWS recruited women in middle age. For 541 women who were participants in both studies, we used statistical measures of association and agreement to compare self-reported MWS data on body size throughout life and reproductive history, obtained in middle age, to NSHD data measured or reported close to the relevant ages. Likely attenuation of estimates of linear disease-exposure associations due to the combined effects of random and systematic errors was quantified using regression dilution ratios (RDRs).</p> <p>Results</p> <p>Data from the two studies were very strongly correlated for current height, weight and body mass index, and age at menopause (Pearson r = 0.91-0.95), strongly correlated for birth weight, parental heights, current waist and hip circumferences and waist-to-height ratio (r = 0.67-0.80), and moderately correlated for age at menarche and waist-to-hip ratio (r = 0.52-0.57). Self-reported categorical body size and clothes size data for various ages were moderately to strongly associated with anthropometry collected at the relevant times (Spearman correlations 0.51-0.79). Overall agreement between the studies was also good for most quantitative variables, although all exhibited both random and systematic reporting error. RDRs ranged from 0.66 to 0.86 for most variables (slight to moderate attenuation), except weight and body mass index (1.02 and 1.04, respectively; little or no attenuation), and age at menarche, birth weight and waist-to-hip ratio (0.44, 0.59 and 0.50, respectively; substantial attenuation).</p> <p>Conclusions</p> <p>This study provides some evidence that self-reported data on certain anthropometric and reproductive factors may be adequate for describing disease-exposure associations in large epidemiological studies, provided that the effects of reporting errors are quantified and the results are interpreted with caution.</p
Diving into the vertical dimension of elasmobranch movement ecology
Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements
Diving into the vertical dimension of elasmobranch movement ecology
Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements
Diving into the vertical dimension of elasmobranch movement ecology
Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements
Impact of Nanocrystal Spray Deposition on Inorganic Solar Cells
Solution-synthesized inorganic cadmium
telluride nanocrystals (∼4 nm; 1.45 eV band gap) are attractive
elements for the fabrication of thin-film-based low-cost photovoltaic
(PV) devices. Their encapsulating organic ligand shell enables them
to be easily dissolved in organic solvents, and the resulting solutions
can be spray-cast onto indium–tin oxide (ITO)-coated glass
under ambient conditions to produce photoactive thin films of CdTe.
Following annealing at 380 °C in the presence of CdCl<sub>2(s)</sub> and evaporation of metal electrode contacts (glass/ITO/CdTe/Ca/Al),
Schottky-junction PV devices were tested under simulated 1 sun conditions.
An improved PV performance was found to be directly tied to control
over the film morphology obtained by the adjustment of spray parameters
such as the solution concentration, delivery pressure, substrate distance,
and surface temperature. Higher spray pressures produced thinner layers
(<60 nm) with lower surface roughness (<200 nm), leading to
devices with improved open-circuit voltages (<i>V</i><sub>oc</sub>) due to decreased surface roughness and higher short-circuit
current (<i>J</i><sub>sc</sub>) as a result of enhanced
annealing conditions. After process optimization, spray-cast Schottky
devices rivaled those prepared by conventional spin-coating, showing <i>J</i><sub>sc</sub> = 14.6 ± 2.7 mA cm<sup>–2</sup>, <i>V</i><sub>oc</sub> = 428 ± 11 mV, FF = 42.8 ±
1.4%, and Eff. = 2.7 ± 0.5% under 1 sun illumination. This optimized
condition of CdTe spray deposition was then applied to heterojunction
devices (ITO/CdTe/ZnO/Al) to reach 3.0% efficiency after light soaking
under forward bias. The film thickness, surface morphology, and light
absorption were examined with scanning electron microscopy, optical
profilometry, and UV/vis spectroscopy
Inorganic Photovoltaic Devices Fabricated Using Nanocrystal Spray Deposition
Soluble
inorganic nanocrystals offer a potential route to the fabrication
of all-inorganic devices using solution deposition techniques. Spray
processing offers several advantages over the more common spin- and
dip-coating procedures, including reduced material loss during fabrication,
higher sample throughput, and deposition over a larger area. The primary
difference observed, however, is an overall increase in the film roughness.
In an attempt to quantify the impact of this morphology change on
the devices, we compare the overall performance of spray-deposited
versus spin-coated CdTe-based Schottky junction solar cells and model
their dark current–voltage characteristics. Spray deposition
of the active layer results in a power conversion efficiency of 2.3
± 0.3% with a fill factor of 45.7 ± 3.4%, <i>V</i><sub>oc</sub> of 0.39 ± 0.06 V, and <i>J</i><sub>sc</sub> of 13.3 ± 3.0 mA/cm<sup>2</sup> under one sun illumination