Local existence for the non-resistive MHD equations in nearly optimal Sobolev spaces

This paper establishes the local-in-time existence and uniqueness of solutions to the viscous, non-resistive magnetohydrodynamics (MHD) equations in RdRd , where d = 2, 3, with initial data B0∈Hs(Rd)B0∈Hs(Rd) and u0∈Hs−1+ϵ(Rd)u0∈Hs−1+ϵ(Rd) for s>d/2s>d/2 and any 0<ϵ<10<ϵ<1 . The proof relies on maximal regularity estimates for the Stokes equation. The obstruction to taking ϵ=0ϵ=0 is explained by the failure of solutions of the heat equation with initial data u0∈Hs−1u0∈Hs−1 to satisfy u∈L1(0,T;Hs+1)u∈L1(0,T;Hs+1) ; we provide an explicit example of this phenomenon

Method for Improving the Pozzolanic Character of Fly Ash

A method for improving the pozzolanic character of fly ash includes the steps of first hydraulically classifying and then flotation separating the fly ash in order to reduce particle size distribution and remove carbon. The method also includes the steps of spiral concentrating separated coarse particles to recover iron, pyrite and marcasite and screening the fly ash to remove ultra-light carbon and plant debris

Block Ionomer Complexes Consisting of siRNA and \u3ci\u3ea\u3c/i\u3eRAFT-Synthesized Hydrophilic-\u3ci\u3eBlock\u3c/i\u3e-Cationic Copolymers II: The Influence of Cationic Block Charge Density on Gene Suppression

Block ionomer complex (BIC)–siRNA interactions and effectiveness in cell transfection are reported. Aqueous RAFT polymerization was used to prepare a series of hydrophilic-block-cationic copolymers in which the cationic block statistically incorporates increasing amounts of neutral, hydrophilic monomer such that the number of cationic groups remains unchanged but the cationic charge density is diluted along the polymer backbone. Reduced charge density decreases the electrostatic binding strength between copolymers and siRNA with the goal of improving siRNA release after targeted cellular delivery. However, lower binding strength resulted in decreased transfection and RNA interference pathway activation, leading to reduced gene knockdown. Enzymatic siRNA degradation studies with BICs indicated lowered binding strength increases susceptibility to RNases, which is the likely cause for poor gene knockdown

Label-Free Characterization of Organic Nanocarriers Reveals Persistent Single Molecule Cores For Hydrocarbon Sequestration

Self-assembled molecular nanostructures embody an enormous potential for new technologies, therapeutics, and understanding of molecular biofunctions. Their structure and function are dependent on local environments, necessitating in-situ/operando investigations for the biggest leaps in discovery and design. However, the most advanced of such investigations involve laborious labeling methods that can disrupt behavior or are not fast enough to capture stimuli-responsive phenomena. We utilize X-rays resonant with molecular bonds to demonstrate an in-situ nanoprobe that eliminates the need for labels and enables data collection times within seconds. Our analytical spectral model quantifies the structure, molecular composition, and dynamics of a copolymer micelle drug delivery platform using resonant soft X-rays. We additionally apply this technique to a hydrocarbon sequestrating polysoap micelle and discover that the critical organic-capturing domain does not coalesce upon aggregation but retains distinct single-molecule cores. This characteristic promotes its efficiency of hydrocarbon sequestration for applications like oil spill remediation and drug delivery. Such a technique enables operando, chemically sensitive investigations of any aqueous molecular nanostructure, label-free

Higher order commutator estimates and local existence for the non-resistive MHD equations and related models

This paper establishes the local-in-time existence and uniqueness of strong solutions in Hs for s > n/2 to the viscous, non-resistive magnetohydrodynamics (MHD) equations in Rn, n = 2, 3, as well as for a related model where the advection terms are removed from the velocity equation. The uniform bounds required for proving existence are established by means of a new estimate, which is a partial generalisation of the commutator estimate of Kato & Ponce (Comm. Pure Appl. Math. 41(7), 891–907, 1988)

Staying true with the help of others: doxastic self-control through interpersonal commitment

I explore the possibility and rationality of interpersonal mechanisms of doxastic self-control, that is, ways in which individuals can make use of other people in order to get themselves to stick to their beliefs. I look, in particular, at two ways in which people can make interpersonal epistemic commitments, and thereby willingly undertake accountability to others, in order to get themselves to maintain their beliefs in the face of anticipated “epistemic temptations”. The first way is through the avowal of belief, and the second is through the establishment of collective belief. I argue that both of these forms of interpersonal epistemic commitment can function as effective tools for doxastic self-control, and, moreover, that the control they facilitate should not be dismissed as irrational from an epistemic perspective

Chemical Inhibition of Alpha-Toxin, a Key Corneal Virulence Factor of Staphylococcus aureus

PURPOSE. ␣-Toxin mediates extreme corneal damage during Staphylococcus aureus keratitis. Chemical inhibition of this toxin was sought to provide relief from toxin-mediated pathology. METHODS. Inhibition of ␣-toxin by phosphate-buffered saline (PBS), 0.1% methyl-␤-cyclodextrin (CD), or CD plus cholesterol (0.1%, CD-cholesterol) was assayed by hemolysis of rabbit erythrocytes. Pathologic changes in rabbit corneas injected with 12 hemolytic units of ␣-toxin suspended in PBS, 1% CD, or 1% CD-cholesterol were compared over time. Rabbit corneas injected with 10 2 colony forming units (CFU) of S. aureus were treated from 7 to 13 hours postinfection (PI) with a total of 15 drops of CD-cholesterol, CD, or PBS. Slit lamp examination (SLE) and measurement of erosions were performed at 13 hours PI and bacteria were quantified at 14 hours PI. RESULTS. Toxin-mediated lysis of erythrocytes was inhibited up to 16,000-fold in the presence of CD-cholesterol compared with CD or PBS. Eyes injected with ␣-toxin mixed with CDcholesterol had, at 7 hours postinjection, significantly smaller erosions than eyes injected with ␣-toxin in PBS or ␣-toxin mixed with CD (P ϭ 0.0090 and P ϭ 0.0035, respectively). Eyes infected with S. aureus and treated with CD-cholesterol had significantly lower SLE scores than eyes treated with CD or PBS (P Յ 0.0103 and P Յ 0.0017, respectively); however, there were no differences in the number of bacteria present (P Ն 0.0648). CONCLUSIONS. CD-cholesterol is a potent inhibitor of ␣-toxin activity in vitro and an effective means to arrest corneal damage during S. aureus keratitis. (Invest Ophthalmol Vis Sci

Childhood leukemia: electric and magnetic fields as possible risk factors.

Numerous epidemiologic studies have reported associations between measures of power-line electric or magnetic fields (EMFs) and childhood leukemia. The basis for such associations remains unexplained. In children, acute lymphoblastic leukemia represents approximately three-quarters of all U.S. leukemia types. Some risk factors for childhood leukemia have been established, and others are suspected. Pathogenesis, as investigated in animal models, is consistent with the multistep model of acute leukemia development. Studies of carcinogenicity in animals, however, are overwhelmingly negative and do not support the hypothesis that EMF exposure is a significant risk factor for hematopoietic neoplasia. We may fail to observe effects from EMFs because, from a mechanistic perspective, the effects of EMFs on biology are very weak. Cells and organs function despite many sources of chemical "noise" (e.g., stochastic, temperature, concentration, mechanical, and electrical noise), which exceed the induced EMF "signal" by a large factor. However, the inability to detect EMF effects in bioassay systems may be caused by the choice made for "EMF exposure." "Contact currents" or "contact voltages" have been proposed as a novel exposure metric, because their magnitude is related to measured power-line magnetic fields. A contact current occurs when a person touches two conductive surfaces at different voltages. Modeled analyses support contact currents as a plausible metric because of correlations with residential magnetic fields and opportunity for exposure. The possible role of contact currents as an explanatory variable in the reported associations between EMFs and childhood leukemia will need to be clarified by further measurements, biophysical analyses, bioassay studies, and epidemiology

Custom Integrated Circuits

Contains reports on six research projects.U.S. Air Force - Office of Scientific Research (Contract F49620-84-C-0004)Analog Devices, Inc.Defense Advanced Research Projects Agency (Contract N00014-80-C-0622)National Science Foundation (Grant ECS83-10941