The Concept of FID-detected Hole-burning in Pulsed EPR Spectroscopy

A new class of pulsed EPR experiments, based on FID-detected hole-burning, is introduced. A transient spectral hole burnt into an inhomogeneously broadened EPR line by means of a selective microwave pulse is shifted or broadened by different types of perturbations and is subsequently recorded in a single experiment via an FID following a nonselective microwave pulse. The proposed approach often exceeds corresponding electron spin-echo experiments with respect to sensitivity and resolution. A number of applications of the FID-detected hole-burning technique are discussed and the predicted features of the new experiments are verified by model calculations and experiments.     

Analysis of Caching and Replication Strategies for Web Applications

Developers often use replication and caching mechanisms to enhance Web application performance. The authors present a qualitative and quantitative analysis of state-of-the art replication and caching techniques used to host Web applications. Their analysis shows that selecting the best mechanism depends heavily on data workload and requires a careful review of the application's characteristics. They also propose a technique for Web practitioners to compare different mechanisms' performance on their own     

Stress corrosion cracking of Ag-20Au in HCLO4, AgCLO4, and KCL solutions by surface mobility

Slow, intermediate, and ultrafast strain-rate experiments were performed on Ag-20Au (atomic percent) wire samples in 1 M HC1O₄, AgClO₄, and KCl solutions. Intergranular stress corrosion cracking was found in all of the solutions tested. In the ultrafast strain-rate experiments, 9.6 s^-1, in HC1O₄ and in AgClO₄ solutions, the size of the cracks proved to be a function of the electric charge circulated before straining. AgClO₄ was also found to specifically induce stress corrosion cracking (SCC) in the Ag-20Au alloy. The surface mobility SCC mechanism was concluded to be the only one that accounted for all of the experimental observations made in the present work.     

Characterization of Pt/L-zeolite catalysts by chemisorption, EXAFS and reaction of neopentane with H2

We have prepared four series of Pt/L-zeolite Catalysts that were calcined at six different temperatures and subsequently reduced at the same temperature (773K). Two series were prepared by ion exchange and two by impregnation. In all cases the dispersion (H/Pt or CO/Pt) was a maximum after calcination at 543–643 K. The Catalysts were further characterized by EXAFS and reaction of neopentane with H₂. There is a good correlation between the particle size determined by chemisorption and the Pt first shell coordination number determined by EXAFS. The neopentane isomerization selectivity ratio was observed to be a linear function of particle size measured by chemisorption or EXAFS coordination number. In addition, enhanced isomerization and hydrogenolysis activities are found to correlate with an increase in the support acidity.     

Unsteady thermal field in bars of doubly connected cross section with heat generation

The title problem is approximately solved by means of a variational formulation. It is shown that in the case of complicated boundary shapes of the cross section, the technique of conformal mapping is, sometimes, quite advantageous. The analytical predictions are compared with the results obtained by means of the finite element method and, in general, good engineering agreement is shown to exist.     

The use of sugar cane stillage for single cell protein production

Stillage from cane molasses alcohol for SCP production was used for the growth of strains of Candida and Paecilomyces as SCP sources. The results of small and large scale experiments carried out with a Candida utilis strain with data on chemical composition, amino acid profile, vitamin content and biological value of the cell material are given.     

Hydrochloric acid leaching of nickel sulfide precipitates

Nickel sulfide precipitates produced by the AMAX Acid Leach Process for oxide nickel ores were leached in hydrochloric acid. The effects of process variables such as temperature, acid concentration, stoichiometric excess of HCl, gas sparging and heat treatment of feed were investigated. The nickel leachability was found to be in the 60–80% range. Chemical and mineralogical examination of the leach residues indicated the presence of NiS₂. This higher nickel sulfide is insoluble in hydrochloric acid, and its presence hinders the leaching of NiS. Several methods are suggested to reduce the sulfur content in order to attain complete dissolution. The thermodynamics and kinetics of nickel sulfide leaching are briefly discussed.     

An organic donor/acceptor lateral superlattice at the nanoscale

A precise control of the nanometer-scale morphology in systems containing mixtures of donor/acceptor molecules is a key factor to improve the efficiency of organic photovoltaic devices. Here we report on a scanning tunneling microscopy study of the first stages of growth of 2-[9-(1,3-dithiol-2-ylidene)anthracen-10(9H)-ylidene]-1,3-dithiole, as electron donor, and phenyl-C61-butyric acid methyl ester, as electron acceptor, on a Au(111) substrate under ultrahigh vacuum conditions. Due to differences in bonding strength with the substrate and different interactions with the Au(111) herringbone surface reconstruction, mixed thin films spontaneously segregate into a lateral superlattice of interdigitated nanoscale stripes with a characteristic width of about 10-20 nm, a morphology that has been predicted to optimize the efficiency of organic solar cells.     

Chromatin Profiling Techniques: Exploring the Chromatin Environment and Its Contributions to Complex Traits

The genetic architecture of complex traits is multifactorial. Genome-wide association studies (GWASs) have identified risk loci for complex traits and diseases that are disproportionately located at the non-coding regions of the genome. On the other hand, we have just begun to understand the regulatory roles of the non-coding genome, making it challenging to precisely interpret the functions of non-coding variants associated with complex diseases. Additionally, the epigenome plays an active role in mediating cellular responses to fluctuations of sensory or environmental stimuli. However, it remains unclear how exactly non-coding elements associate with epigenetic modifications to regulate gene expression changes and mediate phenotypic outcomes. Therefore, finer interrogations of the human epigenomic landscape in associating with non-coding variants are warranted. Recently, chromatin-profiling techniques have vastly improved our understanding of the numerous functions mediated by the epigenome and DNA structure. Here, we review various chromatin-profiling techniques, such as assays of chromatin accessibility, nucleosome distribution, histone modifications, and chromatin topology, and discuss their applications in unraveling the brain epigenome and etiology of complex traits at tissue homogenate and single-cell resolution. These techniques have elucidated compositional and structural organizing principles of the chromatin environment. Taken together, we believe that high-resolution epigenomic and DNA structure profiling will be one of the best ways to elucidate how non-coding genetic variations impact complex diseases, ultimately allowing us to pinpoint cell-type targets with therapeutic potential.     

Tailoring fiber grating sensors for assessment of highly refractive fuels

Three approaches that allow the tailoring of long period gratings based refractometric sensors for concentration measurement in fuel blends are employed to assess the fuel quality in biodiesel and biodiesel-petrodiesel blend. To allow the analysis of fuel samples with refractive index higher than fiber cladding one, the samples refractive indices were changed by thermo-optic effect and by dilution in a standard substance with low refractive index. The obtained results show the sensor can detect oil concentration in biodiesel samples with resolution as better as 0.07% and biodiesel concentration in biodiesel-petrodiesel samples with average resolution of 0.09%.