Cu-doped TiO(2) nanoparticles enhance survival of Shewanella oneidensis MR-1 under ultraviolet light (UV) exposure

It has been shown that photocatalytic TiO₂ nanoparticles (NPs) can be used as an efficient anti-microbial agent under UV light due to generation of reactive oxygen species (ROS), while Shewanella oneidensis MR-1 is a metal-reducing bacterium highly susceptible to UV radiation. Interestingly, we found that the presence of Cu-doped TiO₂ NPs in the cultural medium dramatically increased the survival rates (based on colony-forming unit) of strain MR-1 by over 10,000-fold (incubation without shaking) and ~ 200 fold (incubation with shaking) after a 2-h exposure to UV light. Gene expression results (via qPCR measurement) indicated that the DNA repair gene recA in MR-1 was significantly induced by UV exposure (indicating cellular damage under UV stress), but the influence of NPs on recA expression was not statistically evident. Plausible explanations to NP attenuation of UV stresses are: 1. TiO₂ based NPs are capable of scattering and absorbing UV light and thus create a shading effect to protect MR-1 from UV radiation; 2. more importantly, Cu-doped TiO₂ NPs can co-agglomerate with MR-1 to form large flocs that improves cells' survival against the environmental stresses. This study improves our understanding of NP ecological impacts under natural solar radiation and provides useful insights to application of photocatalytic-NPs for bacterial disinfection.     

Chemical compositions and source identification of PM₂.₅ aerosols for estimation of a diesel source surrogate

Exposure to traffic-related pollution during childhood has been associated with asthma exacerbation, and asthma incidence. The objective of the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) is to determine if the development of allergic and respiratory disease is associated with exposure to diesel engine exhaust particles. A detailed receptor model analyses was undertaken by applying positive matrix factorization (PMF) and UNMIX receptor models to two PM_2.5 data sets: one consisting of two carbon fractions and the other of eight temperature-resolved carbon fractions. Based on the source profiles resolved from the analyses, markers of traffic-related air pollution were estimated: the elemental carbon attributed to traffic (ECAT) and elemental carbon attributed to diesel vehicle emission (ECAD).Application of UNMIX to the two data sets generated four source factors: combustion related sulfate, traffic, metal processing and soil/crustal. The PMF application generated six source factors derived from analyzing two carbon fractions and seven factors from temperature-resolved eight carbon fractions. The source factors (with source contribution estimates by mass concentrations in parentheses) are: combustion sulfate (46.8%), vegetative burning (15.8%), secondary sulfate (12.9%), diesel vehicle emission (10.9%), metal processing (7.5%), gasoline vehicle emission (5.6%) and soil/crustal (0.7%). Diesel and gasoline vehicle emission sources were separated using eight temperature-resolved organic and elemental carbon fractions. Application of PMF to both datasets also differentiated the sulfate rich source from the vegetative burning source, which are combined in a single factor by UNMIX modeling. Calculated ECAT and ECAD values at different locations indicated that traffic source impacts depend on factors such as traffic volumes, meteorological parameters, and the mode of vehicle operation apart from the proximity of the sites to highways. The difference in ECAT and ECAD, however, was less than one standard deviation. Thus, a cost benefit consideration should be used when deciding on the benefits of an eight or two carbon approach.     

Nano Molecular‐Platform: A Protocol to Write Energy Transmission Program Inside a Molecule for Bio‐Inspired Supramolecular Engineering

In a coded self‐assembly, a simple code is written in the molecule, which self‐assembles the molecules into a fractal like structure, which acts as a seed for the next step. As the molecule turns into a complex seed, the code transforms into another form and several seeds self‐assemble into another structure, which acts as a seed for the next step. Until now, this technology was considered as a prerogative of nature. Here, a dendritic network is used to write a basic code by synthetically attaching 32 molecular rotors and doping two controller molecules in its cavity. The code live, which is an energy transmission path in the molecule, is imaged. When the energy transmission path or code is triggered, a series of products generate one after another spontaneously. Two examples are: i) dendritic seed (5–6 nm)→paired nanowire (≈12 nm)→nanowire (≈200 nm)→microwire (500 nm)→wire like rod (1–2 μm)→jelly→rectangular sheet (5 μm). ii) dendritic seed→nano‐sphere (20 nm)→micro‐sphere (500 nm)→large balls(1 μm)→oval shape rod (5–10 μm)→Y, L or T shaped rod assembly. The energy level interactions are tracked using spectroscopy how exactly a directed energy transfer code generates multi‐step synthesis from nano to the visible scale.     

Multisubband electron mobility in a parabolic quantum well structure under the influence of an applied electric field

We study the multisubband electron mobility in a barrier delta doped AlχGal-χAs parabolic quantum well structure under the influence of an applied electric field perpendicular to the interface plane. We consider the alloy fraction χ = 0.3 for barriers and vary x from 0.0 to 0.1 for the parabolic well. Electrons diffuse into the well and confine within the triangular like potentials near the interfaces due to Coulomb interaction with ionized donors. The parabolic structure potential, being opposite in nature, partly compensates the Coulomb potential. The external electric field further amends the potential structure leading to an asymmetric potential profile. Accordingly the energy levels, wave functions and occupation of subbands change. We calculate low temperature electron mobility as a function of the electric field and show that when two subbands are occupied, the mobility is mostly dominated by ionised impurity scattering mediated by intersubband effects. As the field increases transition from double subband to single subband occupancy occurs. A sudden enhancement in mobility is obtained due to curtailment of intersubband effects. Thereafter the mobility is governed by both impurity and alloy disorder scatterings. Our analysis of mobility as a function of the electric field for different structural parameters shows interesting results.     

Multiple forms of complement C3 in trout that differ in binding to complement activators

In all other species analyzed to date, the functionally active form of complement component C3 exists as the product of a single gene. We have now identified and characterized three functional C3 proteins (C3-1, C3-3, and C3-4) in trout that are the products of at least two distinct C3 genes. All three proteins are composed of an alpha-and a beta-chain and contain a thioester bond in the alpha-chain. However, they differ in their electrophoretic mobility, glycosylation, reactivity with monospecific C3 antibodies, and relative ability to bind to various surfaces (zymosan, Escherichia coli, erythrocytes). A comparison of the partial amino acid sequences of the three proteins showed that the amino acid sequence identity/similarity of C3-3 to C3-4 is 87/91%, while that of C3-3 and C3-4 to C3-1 is 51.5/65.5% and 60/73% respectively. Thus, trout possess multiple forms of functional C3 that represent the products of several distinct genes and differ in their ability to bind covalently to various complement activators.     

Modeling high-viscosity,melt-phase,condensation polymer reactors with a time-scales analysis

Mathematical models for simultaneous reaction and mass transfer occurring in the manufacture of high-viscosity, condensation polymers are considered. The specific example of polycondensation of polyethylene terephthalate is examined. Reactor performance is estimated by using a kinetic expression modified by an effectiveness factor. The effectiveness factor is correlated against a ratio of two characteristic times, one identified as the time scale of mixing and the other identified as the time scale of reaction. The time scale of mixing is estimated from experimental mixing data, thereby avoiding the use of potentially inaccurate mixing assumptions. In place of reaction experiments, overall reaction rates are generated using a more detailed mixing-cell model. The effectiveness factor correlation is compared against previous models. Because the correlation is based on predicted reaction rates rather than experimentally measured reaction rates, the value of the present work lies in the demonstration of the time scales modeling technique. © 1995 John Wiley & Sons, Inc.     

Flow through blood vessels under the action of a periodic acceleration field A mathematical analysis

The paper is devoted to an analytical study of flow through blood vessels subjected to a periodic acceleration field. The analysis consists of two parts. In the first case, the wall is treated as a non-linear orthotropic elastic cylindrical membrane and the blood as a Newtonian viscous fluid, while in the second case the experimentally observed material damping properties of the wall tissues and the viscoelasticity of blood have been incorporated in the analysis. In each of these two cases, analytical expressions for the displacement and shear stresses developed in the wall as well as the velocity distribution, fluid acceleration and volume flow rate of blood are derived. The influence of material damping of the wall tissues as well as the viscoelastic properties of blood on the flow and deformation characteristic of a blood vessel has been estimated by using the values of the different material constants (involved in the analysis) determined experimentally for the human abdominal aorta. Numerical results presented in the paper correspond to observed parameters of the circulatory system of living animals.     

Hemostasis in acquired hemophilia--role of intracavitary instillation of EACA

An 82 year old man developed antibodies against coagulation factor VIII:C without any apparent cause. Bleeding from the soft tissue cavity could not be controlled by factor VIII:C concentrates, immunosuppression with steroids and intravenous immunoglobulin therapy in the standard dosages. However, a single injection of Epsilon Aminocaproic Acid (EACA) instilled into the cavity under aseptic precautions achieved lasting hemostasis with resultant wound healing.     

Solutions of hydrochloric acid in formamide—IV. Thermodynamic properties from the study of cells using the quinhydrone electrode at 25°C

The emf of cells Ag AgCl, HCl(m), QH₂, Q Pt, Hg Hg₂Cl₂, HCl(m), QH₂, Q Pt and Pt H₂, HCl(m), QH₂, Q Pt have been measured at 25°C using formamide as solvent. The standard potential of the quinhydrone electrode obtained from the above cells is 0·7151 ± 0·0009, 0·7137 ± 0·0005 and 0·7140 ± 0·0002 V respectively. The calculated mean molal activity coefficients of HCl agree fairly well with earlier reported results.