618 research outputs found

    Constitutional Criminal Procedure - Due Process - Judgment and Sentence - Judge\u27s Discretion to Consider Defendant\u27s False Testimony

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    The United States Supreme Court has held that neither the due process clause nor 18 U.S.C. § 3481, which guarantees a criminal defendant\u27s right to take the stand in his own defense, precludes a judge, in determining sentence, from taking into account his belief that the defendant\u27s testimony under oath contained willful and material falsehoods. United States v. Grayson, 98 S. Ct. 2610 (1978

    A self‐consistent model of Γ‐X mixing in GaAs/AlAs/GaAs quantum well structures using the quantum transmitting boundary method

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    We present a numerical study of the Γ‐X mixing in GaAs/AlAs/GaAs quantum well structures. A Γ‐X mixing model proposed by Liu [Appl. Phys. Lett. 51, 1019 (1987)] is extended to include the effects of self‐consistency and nonzero transverse momentum. In the present model, the coupled Schrödinger equations for Γ and X electron envelope wave functions are solved self‐consistently with Poisson’s equation to calculate the electron transmission probability and wave functions, which lead to the current‐voltage (I‐V) characteristics of single barrier and double barrier resonant tunneling diode structures. The quantum transmitting boundary method is employed in the model for numerical solution of the coupled Schrödinger equations, which proves to be very stable and efficient, even for large (≳2000 Å) structures. The features of Γ‐X mixing, such as the resonance/antiresonance in the transmission probability and the virtual bound states, are clearly demonstrated. Additional physical features are observed in the transmission probability and the wave functions under applied bias conditions. Our work shows that inclusion of transverse momentum, variable effective mass, and the self‐consistent potential is important in the realistic modeling of I‐V characteristics for structures exhibiting Γ‐X coupling.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69686/2/JAPIAU-74-8-5053-1.pd

    Proceedings of a conference on Cardiovascular Bioinstrumentation

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    The Ames Research Center (ARC) has a long history in the development of cardiovascular (CV) instrumentation for human and animal research. The ARC Cardiovascular Research Lab under the Space Physiology Branch, Space Research Directorate, supports both ground-based and space-based animal and human research goals. The Cardiovascular Research Laboratory was established at ARC in the mid 1960's to conduct ground-based animal research and support development of advanced cardiovascular instrumentation applicable to spaceflight. The ARC Biomedical Research Program also conducts human studies with a CV instrumentation focus

    A retrospective analysis of geriatric trauma patients: venous lactate is a better predictor of mortality than traditional vital signs

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    BACKGROUND: Traditional vital signs (TVS), including systolic blood pressure (SBP), heart rate (HR) and their composite, the shock index, may be poor prognostic indicators in geriatric trauma patients. The purpose of this study is to determine whether lactate predicts mortality better than TVS. METHODS: We studied a large cohort of trauma patients age ≄ 65 years admitted to a level 1 trauma center from 2009-01-01 - 2011-12-31. We defined abnormal TVS as hypotension (SBP < 90 mm Hg) and/or tachycardia (HR > 120 beats/min), an elevated shock index as HR/SBP ≄ 1, an elevated venous lactate as ≄ 2.5 mM, and occult hypoperfusion as elevated lactate with normal TVS. The association between these variables and in-hospital mortality was compared using Chi-square tests and multivariate logistic regression. RESULTS: There were 1987 geriatric trauma patients included, with an overall mortality of 4.23% and an incidence of occult hypoperfusion of 20.03%. After adjustment for GCS, ISS, and advanced age, venous lactate significantly predicted mortality (OR: 2.62, p < 0.001), whereas abnormal TVS (OR: 1.71, p = 0.21) and SI ≄ 1 (OR: 1.18, p = 0.78) did not. Mortality was significantly greater in patients with occult hypoperfusion compared to patients with no sign of circulatory hemodynamic instability (10.67% versus 3.67%, p < 0.001), which continued after adjustment (OR: 2.12, p = 0.01). CONCLUSIONS: Our findings demonstrate that occult hypoperfusion was exceedingly common in geriatric trauma patients, and was associated with a two-fold increased odds of mortality. Venous lactate should be measured for all geriatric trauma patients to improve the identification of hemodynamic instability and optimize resuscitative efforts

    Dynamic instabilities in resonant tunneling induced by a magnetic field

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    We show that the addition of a magnetic field parallel to the current induces self sustained intrinsic current oscillations in an asymmetric double barrier structure. The oscillations are attributed to the nonlinear dynamic coupling of the current to the charge trapped in the well, and the effect of the external field over the local density of states across the system. Our results show that the system bifurcates as the field is increased, and may transit to chaos at large enough fields.Comment: 4 pages, 3 figures, accepted in Phys. Rev. Letter

    Time Dependent Current Oscillations Through a Quantum Dot

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    Time dependent phenomena associated to charge transport along a quantum dot in the charge quantization regime is studied. Superimposed to the Coulomb blockade behaviour the current has novel non-linear properties. Together with static multistabilities in the negative resistance region of the I-V characteristic curve, strong correlations at the dot give rise to self-sustained current and charge oscillations. Their properties depend upon the parameters of the quantum dot and the external applied voltages.Comment: 4 pages, 3 figures; to appear in PR

    Translational Cell & Animal Research in Space 1965-2011

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    Translational Cell and Animal Research (TCAR). For nearly 50 years, the NASA Space Biology Program has funded, and Ames Research Center (ARC) has managed, a robust program of fundamental research including studies using a wide range of animal cells, tissues and organisms. Much of this research was conducted on spacecraft in microgravity environments including diverse platforms such as: Gemini Spacecraft, US Biosatellites, Apollo Command Modules, Skylabs, Russian Biosatellites, NASA Space Shuttles, NASA/Mir, and most recently, the International Space Station (ISS). During the Space Shuttle Era (19812011), the science of space biology took an enormous step forward with 45 missions that afforded researchers with new opportunities to conduct systematic and complex experiments aimed at a deeper understanding of how life adapts to the space environment. Beginning in the 1990s, the products of these experiments, comprised of research summaries and rare, unused biospecimens, were collected and catalogued within the ARC Life Sciences Data Archiving Office, a branch of NASAs Life Sciences Data Archive (LSDA) managed from the NASA Johnson Spaceflight Center

    Injury severity and serum amyloid A correlate with plasma oxidation-reduction potential in multi-trauma patients: a retrospective analysis

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    <p>Abstract</p> <p>Background</p> <p>In critical injury, the occurrence of increased oxidative stress or a reduced antioxidant status has been observed. The purpose of this study was to correlate the degree of oxidative stress, by measuring the oxidation-reduction potential (ORP) of plasma in the critically injured, with injury severity and serum amyloid A (SAA) levels.</p> <p>Methods</p> <p>A total of 140 subjects were included in this retrospective study comprising 3 groups: healthy volunteers (N = 21), mild to moderate trauma (ISS < 16, N = 41), and severe trauma (ISS ≄ 16, N = 78). For the trauma groups, plasma was collected on an almost daily basis during the course of hospitalization. ORP analysis was performed using a microelectrode, and ORP maxima were recorded for the trauma groups. SAA, a sensitive marker of inflammation in critical injury, was measured by liquid chromatography/mass spectrometry.</p> <p>Results</p> <p>ORP maxima were reached on day 3 (± 0.4 SEM) and day 5 (± 0.5 SEM) for the ISS < 16 and ISS ≄ 16 groups, respectively. ORP maxima were significantly higher in the ISS < 16 (-14.5 mV ± 2.5 SEM) and ISS ≄ 16 groups (-1.1 mV ± 2.3 SEM) compared to controls (-34.2 mV ± 2.6 SEM). Also, ORP maxima were significantly different between the trauma groups. SAA was significantly elevated in the ISS ≄ 16 group on the ORP maxima day compared to controls and the ISS < 16 group.</p> <p>Conclusion</p> <p>The results suggest the presence of an oxidative environment in the plasma of the critically injured as measured by ORP. More importantly, ORP can differentiate the degree of oxidative stress based on the severity of the trauma and degree of inflammation.</p

    IgG light chain-independent secretion of heavy chain dimers: consequence for therapeutic antibody production and design

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    Rodent monoclonal antibodies with specificity towards important biological targets are developed for therapeutic use by a process of humanisation. This process involves the creation of molecules, which retain the specificity of the rodent antibody but contain predominantly human coding sequence. Here we show that some humanised heavy chains can fold, form dimers and be secreted even in the absence of light chain. Quality control of recombinant antibody assembly in vivo is thought to rely upon folding of the heavy chain CH1 domain. This domain acts as a switch for secretion, only folding upon interaction with the light chain CL domain. We show that the secreted heavy-chain dimers contain folded CH1 domains and contribute to the heterogeneity of antibody species secreted during the expression of therapeutic antibodies. This subversion of the normal quality control process is dependent upon the heavy chain variable domain, is prevalent with engineered antibodies and can occur when only the Fab fragments are expressed. This discovery will impact on the efficient production of both humanised antibodies as well as the design of novel antibody formats
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