Comparison of the mean photospheric magnetic field and the interplanetary magnetic field

Polarity comparison of solar magnetic field and interplanetary magnetic fiel

Communications Biophysics

Contains reports on five research projects.National Institutes of Health (Grant 1 P01 GM-14940-01)Joint Services Electronics Program under Contract DA 28-043-AMC-02536(E

Communications Biophysics

Contains reports on three research projects.National Institutes of Health (Grant 5 P01 GM14940-04

Reactive and responsive functionalized membranes

Surface functionalization of traditional NF, RO, and UF membranes to reduce fouling has been widely reported in the literature. On the other hand, pore functionalization of MF membranes through in-situ polymerization or attachment of macromolecules brings in new opportunities through pore conformation change and creation of high density active sites. These approaches dramatically enhance the applications of membranes in water and bio-nano field. The development of responsive, multifunctional materials and membranes for environmental applications requires a high level of control of both the characteristics of the base polymeric or inorganic support layer, as well as, its corresponding surface properties. Synthesis of membranes functionalized with appropriate macromolecules or reactive groups or enzymes and nano-catalytic particles can indeed provide applications ranging from tunable flux and separations, high-capacity metal capture, to toxic organic degradation by nanoparticles or enzymes. The use of macromolecules, such as, poly-acrylic acid (PAA), poly-glutamic acid (PLGA) provides pH responsive behavior pH modulations, whereas poly-N-isopropylacrylamide (pNIPAAm) provides temperature responsive behavior. The dependence of conformation properties of polyelectrolytes provides tunable separation and membrane flux control by pH or temperature based stimuli responsive properties. Layer-by-layer (LbL) assembly technique, most commonly conducted by intercalation of positive and negative polyelectrolytes or polypeptides, is a powerful, versatile and simple method for assembling supramolecular structures where enzymes or precise porin channels can be incorporated. The presentation will include: (1) synthesis and pore functionalization approaches, and direct polymerization of acrylic acid in membrane pores (lab-scale to full-scale), (2) pH and temperature responsive behavior, and catalytic nanoparticle synthesis in pores for environmentally important reductive and oxidative reactions, (3) pore functionalized (LbL approach) membranes for enzymatic (glucose oxidase and laccase), and environmentally important reactions,(4) porin channels for selective separations, (5) combination NF-Functionalized membrane process for practical applications in energy industries. The authors acknowledge the support of NSF KY EPSCoR program, NIH-NIEHS-SRC program, Southern services Co, Chevron Corporation, and Nanostone Membranes for full-scale membrane development work. The authors also acknowledge the highly significant research contributions of Drs. Li, Lewis, Ritchie, Hestekin, Meeks, and Gui

Shock formation and the ideal shape of ramp compression waves

We derive expressions for shock formation based on the local curvature of the flow characteristics during dynamic compression. Given a specific ramp adiabat, calculated for instance from the equation of state for a substance, the ideal nonlinear shape for an applied ramp loading history can be determined. We discuss the region affected by lateral release, which can be presented in compact form for the ideal loading history. Example calculations are given for representative metals and plastic ablators. Continuum dynamics (hydrocode) simulations were in good agreement with the algebraic forms. Example applications are presented for several classes of laser-loading experiment, identifying conditions where shocks are desired but not formed, and where long duration ramps are desired

Monitoring of Tumor Promotion and Progression in a Mouse Model of Inflammation-Induced Colon Cancer with Magnetic Resonance Colonography

AbstractEarly detection of precancerous tissue has significantly improved survival of most cancers including colorectal cancer (CRC). Animal models designed to study the early stages of cancer are valuable for identifying molecular events and response indicators that correlate with the onset of disease. The goal of this work was to investigate magnetic resonance (MR) colonography in a mouse model of CRC on a clinical MR imager. Mice treated with azoxymethane and dextran sulfate sodium were imaged by serial MR colonography (MRC) from initiation to euthanasia. Magnetic resonance colonography was obtained with both T1- and T2-weighted images after administration of a Fluorinert enema to remove residual luminal signal and intravenous contrast to enhance the colon wall. Individual tumor volumes were calculated and validated ex vivo. The Fluorinert enema provided a clear differentiation of the lumen of the colon from the mucosal lining. Inflammation was detected 3 days after dextran sulfate sodium exposure and subsided during the next week. Tumors as small as 1.2 mm3 were detected and as early as 29 days after initiation. Individual tumor growths were followed over time, and tumor volumes were measured by MR imaging correlated with volumes measured ex vivo. The use of a Fluorinert enema during MRC in mice is critical for differentiating mural processes from intraluminal debris. Magnetic resonance colonography with Fluorinert enema and intravenous contrast enhancement will be useful in the study of the initial stages of colon cancer and will reduce the number of animals needed for preclinical trials of prevention or intervention

Human interaural time difference thresholds for sine tones: The high-frequency limit

[EN] The smallest detectable interaural time difference (ITD) for sine tones was measured for four human listeners to determine the dependence on tone frequency. At low frequencies, 250 700 Hz, threshold ITDs were approximately inversely proportional to tone frequency. At mid-frequencies, 700 1000 Hz, threshold ITDs were smallest. At high frequencies, above 1000 Hz, thresholds increased faster than exponentially with increasing frequency becoming unmeasurably high justabove 1400 Hz. A model for ITD detection began with a biophysically based computational model for a medial superior olive (MSO) neuron that produced robust ITD responses up to 1000 Hz, and demonstrated a dramatic reduction in ITD-dependence from 1000 to 1500 Hz. Rate-ITD functions from the MSO model became inputs to binaural display models both place based and rate-differ-ence based. A place-based, centroid model with a rigid internal threshold reproduced almost all fea- tures of the human data. A signal-detection version of this model reproduced the high-frequence divergence but badly underestimated low-frequency thresholds. A rate-difference model incorporat- ing fast contralateral inhibition reproduced the major features of the human threshold data except for the divergence. A combined, hybrid model could reproduce all the threshold data.We are grateful to Dr. Les Bernstein for a useful discussion about the centroid display and to Dr. Steve Colburn for discussions about modeling. Zane Crawford provided valuable statistical help. This research was supported by The Vicerectorado de Profesorado y Ordenacion Academica of the Universitat Politecnica de Valencia (Spain), which brought L. D. to Michigan State, by the NIDCD Grant No. DC-00181 and the AFOSR Grant No. 11NL002. A. B. was supported by NIDCD Grant Nos. DC-00100 (H. S. Colburn) and P30-DC04663 (Core Center).Brughera, A.; Dunai ., L.; Hartmann, WM. (2013). Human interaural time difference thresholds for sine tones: The high-frequency limit. The Journal of the Acoustical Society of America. 133(5):2839-2855. https://doi.org/10.1121/1.4795778S28392855133

On malfunctioning software

Artefacts do not always do what they are supposed to, due to a variety of reasons, including manufacturing problems, poor maintenance, and normal wear-and-tear. Since software is an artefact, it should be subject to malfunctioning in the same sense in which other artefacts can malfunction. Yet, whether software is on a par with other artefacts when it comes to malfunctioning crucially depends on the abstraction used in the analysis. We distinguish between “negative” and “positive” notions of malfunction. A negative malfunction, or dysfunction, occurs when an artefact token either does not (sometimes) or cannot (ever) do what it is supposed to. A positive malfunction, or misfunction, occurs when an artefact token may do what is supposed to but, at least occasionally, it also yields some unintended and undesirable effects. We argue that software, understood as type, may misfunction in some limited sense, but cannot dysfunction. Accordingly, one should distinguish software from other technical artefacts, in view of their design that makes dysfunction impossible for the former, while possible for the latter