Investigation of hydrogen generation from sodium borohydride using different cobalt catalysts

Effective Co/Cu, CoB/Cu, and CoBM (M = Mo,Zn,Fe)/Cu catalysts were prepared on the copper surface by a simple electroless deposition method using a morpholine borane as a reducing agent in the glycine solution. The activity of the deposited catalysts was investigated for hydrogen generation from an alkaline sodium borohydride solution. It was determined that these synthesized catalysts demonstrated the catalytic activity for the hydrolysis reaction of NaBH₄. The lowest obtained activation energy (E_A) of the hydrolysis reaction of NaBH₄was 27 kJ mol^?1 for the CoBMo/Cu catalyst. The hydrogen generation rate of 15.30 ml min^?1 was achieved using CoBMo/Cu catalysts at 313 K and it increased ~3.5 times with the increase of temperature to 343 K. The highest hydrogen generation rate obtained by CoBMo/Cu films may be related to the hierarchical cauliflower-shaped 3D structures and the high roughness surface area. Moreover, the CoBMo/Cu catalyst showed an excellent reusability.     

The Effect of Electroporation of a Lyotroic Liquid Crystal Genistein-Based Formulation in the Recovery of Murine Melanoma Lesions

A lamellar lyotropic liquid crystal genistein-based formulation (LLC-Gen) was prepared in order to increase the aqueous solubility of the lipophilic phytocompound genistein. The formulation was applied locally, in a murine model of melanoma, with or without electroporation. The results demonstrated that, when the formulation was applied by electroporation, the tumors appeared later. During the 21 days of the experiment, the LLC-Gen formulation decreased the tumor volume, the amount of melanin and the degree of erythema, but when electroporation was applied, all these parameters indicated a better prognosis even (lower tumor volume, amount of melanin and degree of erythema). Although hematoxylin–eosin (HE) staining confirmed the above events, application of the LLC-Gen formulation by electroporation did not lead to a significant effect in terms of the serum concentrations of the protein S100B and serum neuron specific enolase (NSE), or the tissue expression of the platelet-derived growth factor receptor β (PDGFRβ) antibody.     

Searching for motifs in the behaviour of larval Drosophila melanogaster and Caenorhabditis elegans reveals continuity between behavioural states

We present a novel method for the unsupervised discovery of behavioural motifs in larval Drosophila melanogaster and Caenorhabditis elegans. A motif is defined as a particular sequence of postures that recurs frequently. The animal''s changing posture is represented by an eigenshape time series, and we look for motifs in this time series. To find motifs, the eigenshape time series is segmented, and the segments clustered using spline regression. Unlike previous approaches, our method can classify sequences of unequal duration as the same motif. The behavioural motifs are used as the basis of a probabilistic behavioural annotator, the eigenshape annotator (ESA). Probabilistic annotation avoids rigid threshold values and allows classification uncertainty to be quantified. We apply eigenshape annotation to both larval Drosophila and C. elegans and produce a good match to hand annotation of behavioural states. However, we find many behavioural events cannot be unambiguously classified. By comparing the results with ESA of an artificial agent''s behaviour, we argue that the ambiguity is due to greater continuity between behavioural states than is generally assumed for these organisms.     

An efficient method for PET image denoising by combining multi-scale transform and non-local means

Multimedia Tools and Applications - The diagnosis of dementia, particularly in the early stages is very much helpful with Positron emission tomography (PET) image processing. The most important...     

Improving accessibility of CMS-based websites using automated methods

Universal Access in the Information Society - New methods of identifying and fixing accessibility issues on websites are presented in this article. The websites taken into consideration by the...     

Unbiased Light Transport Estimators for Inhomogeneous Participating Media

This paper presents a new stochastic particle model for efficient and unbiased Monte Carlo rendering of heterogeneous participating media. We randomly add and remove material particles to obtain a density with which free flight sampling and transmittance estimation are simple, while material particle properties are simultaneously modified to maintain the true expectation of the radiance. We show that meeting this requirement may need the introduction of light particles with negative energy and materials with negative extinction, and provide an intuitive interpretation for such phenomena. Unlike previous unbiased methods, the proposed approach does not require a‐priori knowledge of the maximum medium density that is typically difficult to obtain for procedural models. However, the method can benefit from an approximate knowledge of the density, which can usually be acquired on‐the‐fly at little extra cost and can greatly reduce the variance of the proposed estimators. The introduced mechanism can be integrated in participating media renderers where transmittance estimation and free flight sampling are building blocks. We demonstrate its application in a multiple scattering particle tracer, in transmittance computation, and in the estimation of the inhomogeneous air‐light integral.     

Electrical conductivity of poly(2-ethynylthiophene) and poly(2-ethynylfuran) doped with electron acceptors

The electrical conductivity of poly(2-ethynylthiophene) (P2ET) and poly(2-ethynylfuran) (P2EF) doped with electron acceptors such as iodine, bromine, and ferric chloride was investigated. The maximum electrical conductivities of P2ET and P2EF doped with iodine were 3 × 10^?4 Ω^?1 cm^?1 and 5 × 10^?3 Ω^?1 cm^?1, respectively. The electrical conductivity was nearly independent with increasing molecular weight. The spectral measurements such as UV-visible, infrared, electron paramagnetic resonance, thermogravimetric analysis, and X-ray diffraction were also carried out.     

The Palladium(II) Complex of Aβ4−16 as Suitable Model for Structural Studies of Biorelevant Copper(II) Complexes of N-Truncated Beta-Amyloids

The Aβ4−42 peptide is a major beta-amyloid species in the human brain, forming toxic aggregates related to Alzheimer’s Disease. It also strongly chelates Cu(II) at the N-terminal Phe-Arg-His ATCUN motif, as demonstrated in Aβ4−16 and Aβ4−9 model peptides. The resulting complex resists ROS generation and exchange processes and may help protect synapses from copper-related oxidative damage. Structural characterization of Cu(II)Aβ4−x complexes by NMR would help elucidate their biological function, but is precluded by Cu(II) paramagneticism. Instead we used an isostructural diamagnetic Pd(II)-Aβ4−16 complex as a model. To avoid a kinetic trapping of Pd(II) in an inappropriate transient structure, we designed an appropriate pH-dependent synthetic procedure for ATCUN Pd(II)Aβ4−16, controlled by CD, fluorescence and ESI-MS. Its assignments and structure at pH 6.5 were obtained by TOCSY, NOESY, ROESY, 1H-13C HSQC and 1H-15N HSQC NMR experiments, for natural abundance 13C and 15N isotopes, aided by corresponding experiments for Pd(II)-Phe-Arg-His. The square-planar Pd(II)-ATCUN coordination was confirmed, with the rest of the peptide mostly unstructured. The diffusion rates of Aβ4−16, Pd(II)-Aβ4−16 and their mixture determined using PGSE-NMR experiment suggested that the Pd(II) complex forms a supramolecular assembly with the apopeptide. These results confirm that Pd(II) substitution enables NMR studies of structural aspects of Cu(II)-Aβ complexes.     

Influence of principal component analysis acceleration factor on velocity measurement in 2D and 4D PC-MRI

Objective

The objective of the study was to determine how to optimize 2D and 4D phase-contrast magnetic resonance imaging (PC-MRI) acquisitions to acquire flow velocities in millimetric vessels. In particular, we search for the best compromise between acquisition time and accuracy and assess the influence of the principal component analysis (PCA).

Materials and methods

2D and 4D PC-MRI measurements are conducted within two in vitro vessel phantoms: a Y-bifurcation phantom, the branches of which range from 2 to 5 mm in diameter, and a physiological subject-specific phantom of the carotid bifurcation. The same sequences are applied in vivo in carotid vasculature.

Results

For a vessel oriented in the axial direction, both 2D and axial 4D PC-MRI provided accuracy measurements regardless of the k-t PCA factor, while the acquisition time is reduced by a factor 6 for k-t PCA maximum value. The in vivo measurements show that the proposed sequences are adequate to acquire 2D and 4D velocity fields in millimetric vessels and with clinically realistic time durations.

Conclusion

The study shows the feasibility of conducting fast, high-resolution PC-MRI flow measurements in millimetric vessels and that it is worth maximizing the k-t PCA factor to reduce the acquisition time in the case of 2D and 4D axial acquisitions.

     

Modeling and simulation of photon-coupled,fluorescent photoswitchable protein logic

Today's society has an ever-increasing demand for smaller-scale, lower-energy-consuming, cheaper, and faster computing and digital signal processing systems. Photon-coupled, fluorescent photoswitchable protein-based architectures are promising candidates for the fulfillment of these requirements. In order to properly design digital circuits based on the aforementioned building blocks, an efficient simulation procedure is needed. We present a simple, differential equation-based model, suitable for the design and simulation of such structures. It characterizes the radiation-induced switching, the form-dependent fluorescence, and the effect of photon coupling in a fast and efficient manner. The applicability of the model is demonstrated through simulations of the OR and NOR logic gates consisting of readily available, fluorescent photoswitchable proteins. It can be a potential design tool for future molecular logic circuitry based on such molecules.