Velocity of water diffusion through germanium oxide

The diffusion of water through an oxide film on germanium was investigated by measurement of the surface conductivity, and a relation was found between the coefficient of diffusion and the humidity of the ambient medium.     

A controllable laboratory stock market for modeling real stock markets

Based on the different research approaches, econophysics can be divided into threedirections: empirical econophysics, computationaleconophysics, and experimental econophysics. Becauseempirical econophysics lacks controllability that is needed to studythe impacts of different external conditions and computational econophysicshas to adopt artificial decision-making processes that are often deviated fromthose of real humans, experimental econophysics tends to overcome theseproblems by offering controllability and using real humans in laboratory experiments.However, to our knowledge, the existing laboratory experiments have not convincinglyreappeared the stylized facts (say, scaling) that have been revealed for realeconomic/financial markets by econophysicists. A most important reason is that in theseexperiments, discrete trading time makes these laboratory markets deviated from realmarkets where trading time is naturally continuous. Here we attempt to overcome thisproblem by designing a continuous double-auction stock-trading market and conductingseveral human experiments in laboratory. As an initial work, the present artificialfinancial market can reproduce some stylized facts related to clustering and scaling.Also, it predicts some other scaling in human behavior dynamics that is hard to achieve inreal markets due to the difficulty in getting the data. Thus, it becomes possible to studyreal stock markets by conducting controlled experiments on such laboratory stock marketsproducing high frequency data.     

Determination of the surface pK of carboxylic- and amine-terminated alkanethiols using surface plasmon resonance spectroscopy

When using self-assembled monolayers (SAMs) with ionizable functional groups, such as COOH and NH2, the dissociation constant (pKd) of the surface is an important property to know, since it defines the charge density of the surface for a given bulk solution pH. In this study, we developed a method using surface plasmon resonance (SPR) spectroscopy for the direct measurement of the pKd of a SAM surface by combining the ability of SPR to detect the change in mass concentration close to a surface and the shift in ion concentration over the surface as a function of surface charge density. This method was then applied to measure the pKd values of both COOH- and NH2-functionalized SAM surfaces using solutions of CsCl and NaBr salts, respectively, which provided pKd values of 7.4 and 6.5, respectively, based on the bulk solution pH. An analytical study was also performed to theoretically predict the shape of the SPR plots by calculating the excess mass of salt ions over a surface as a function of the difference between the solution pH and surface pKd. The analytical relationships show that the state of surface charge also influences the local hydrogen ion concentration, thus resulting in a substantial local shift in pH at the surface compared to the bulk solution as a function of the difference between the bulk solution pH and the pKd of the surface.     

Relaxation and anharmonic couplings of the O-H stretching vibration of asymmetric strongly hydrogen-bonded complexes

We present infrared transient grating measurements of complexes of formic acid with pyridine and pyrazine at four excitation frequencies within the broad proton-stretching band. These experiments investigate the mechanism of the line broadening of the O-H stretching vibration. The transients show coherent oscillations that decay within a few hundred femtoseconds and population relaxation on two time scales. We fit the data using a simple model of three coupled oscillators that relax via sequential kinetics through an intermediate state. Based on this model, we conclude that the coherent oscillations result from superpositions of Fermi-resonance-coupled states involving formic acid overtone and combination states.     

Spectroscopic linear dichroism FT-IR studies of synthetic spider silk

This work deals with the analysis of the orientation behavior of different segments of synthetic spider silk samples containing hard and soft segments. Two different types of spider silk were examined, one with an aliphatic hard segment (hexamethylene-diisocyanate) and an amorphous soft segment (polytetramethylene oxide) (A40) and the other with an aromatic hard segment (4,4′-methylene bisphenyl diisocyanate) and a semicrystalline soft segment (polyethylene oxide-polypropylene oxide- polyethylene oxide) (A143). In order to observe the orientation behavior of the hard and the soft segments it was necessary to define marker bands. While for both samples the chosen marker bands for the hard segments were the same, the marker bands for the soft segments were different. FT-IR spectra were recorded while strain was applied to the material at the same time. Two parameters, the dichroic ratio R and the order Parameter f were used to evaluate the behavior of these materials under conditions of strain. It was found that sample A143 broke at a strain level of 37,5 %, while sample A40 showed a high dynamic range up to a strain level of 307 %.     

Vector fuzzy control iterative algorithm for the design of sub-wavelength diffractive optical elements for beam shaping

The vector fuzzy control iterative algorithm (VFCIA) is proposed for the design of phase-only sub-wavelength diffractive optical elements (SWDOEs) for beam shaping. The vector diffraction model put forward by Mansuripur is applied to relate the field distributions between the SWDOE plane and the output plane. Fuzzy control theory is used to decide the constraint method for each iterative process of the algorithm. We have designed a SWDOE that transforms a circular flat-top beam to a square irradiance pattern. Computer design results show that the SWDOE designed by the VFCIA can produce better results than the vector iterative algorithm (VIA). And the finite difference time-domain method (FDTD), a rigorous electromagnetic analysis technique, is used to analyze the designed SWDOE for further confirming the validity of the proposed method.     

Novel porphyrin conjugates with a potent photodynamic antitumor effect: differential efficacy of mono- and bis-beta-cyclodextrin derivatives in vitro and in vivo

In the present study we investigated the photosensitizing properties of two novel mono- and bis-cyclodextrin tetrakis (pentafluorophenyl) porphyrin derivatives in several tumor cell lines and in BALB/c mice bearing subcutaneously transplanted syngeneic mouse mammary carcinoma 4T1. Both studied sensitizers were localized mainly in lysosomes and were found to induce cell death by triggering apoptosis in human leukemic cells HL-60. In 4T1 and other cell lines both apoptotic and necrotic modes of cell death occurred depending on drug and light doses. Mono-cyclodextrin porphyrin derivative P(beta-CD)1 exhibited stronger in vitro phototoxic effect than bis-cyclodextrin derivative P(beta-CD)2. However, in vivo P(beta-CD)2 displayed faster tumor uptake with maximal accumulation 6 h after application, leading to complete and prolonged elimination of subcutaneous tumors within 3 days after irradiation (100 J cm(-2)). In contrast, P(beta-CD)1 uptake was slower (48 h) and the reduction of tumor mass was only transient, reaching the maximum at the 12 h interval when a favorable tumor-to-skin ratio appeared. Thus, P(beta-CD)2 represents a new photosensitizing drug displaying fast and selective tumor uptake, strong antitumor activity and fast elimination from the body.     

Investigation of novel monopodal and dipodal oxy-Schiff base triazine from cyanuric chloride: Structural and antimicrobial studies

During the last few years, the potential of s-triazine derivatives in agrochemical and medicinal properties have been subjected to investigation. s-Triazine derivatives have received great attention due to their significant antimicrobial, antibacterial, antifungal, anti-HIV, anticancer, and a wide array of other biological activities. The present study reported a method for achieving Dipodal systems formed by reaction 2,4,6-trichloro-1,3,5-triazine and 4-hydroxybenzaldehyde, 2-aminophenol. Herein, we reported the synthesis of a dialdehyde and its Schiff base as a new template. The reaction of cyanuric chloride with 1 equiv. methanol and 2 equiv. of p-hydroxybenzaldehyde gave the desired dialdehyde. The dialdehyde was then reacted with 2-aminophenolto afford the corresponding multidirectional oxy-Schiff base triazines. The structures of the compounds were identified by FT-IR,¹H-NMR and elemental analysis. Their antimicrobial activities were performed by using the broth microdilution method in DMSO: Phosphate Buffered Saline (PBS) against eight bacteria strain and one yeast strain. The results of the test were compared with gentamicin. It has been determined that 2,4-Bis(2-hydroxyphenylimino-4'-formylphenoxy)-6-methoxy-1,3,5-triazine (3) Padalkar, V. S., Gupta, V. D., Phatangare, K. R., Patil, V. S., Umape, P. G., Sekar, N. J. (2014) Saudi. Chem. Soc., 18, 262–268.[Crossref], [Web of Science ®] , [Google Scholar] (2DP2AF) and 2-(2-hydroxyphenylimino-4'-formylphenoxy)-4-(4'-formylphenoxy)-6-methoxy-1,3,5-triazine (2) Raval, J. P., Rai, A. R., Patel, N. H., Patel, H. V., Patel, P. S. (2009) Int. J. Chem. Tech. Res., 1, 616–620. [Google Scholar] (1DP2AF) have significant antibacterial and antifungal activity against Enterococcus faecalis and Candida albicans and these effects were close to the control antibiotic used. Ent. faecalis was the most sensitive strain against both two tested chemicals. It was determined that our chemicals have similar antifungal capacity when compared to gentamicin.     

Low-molecular weight protein profiling of genetically modified maize using fast liquid chromatography electrospray ionization and time-of-flight mass spectrometry

In this work, the use of liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC-TOFMS) has been evaluated for the profiling of relatively low-molecular weight protein species in both genetically modified (GM) and non-GM maize. The proposed approach consisted of a straightforward sample fractionation with different water and ethanol-based buffer solutions followed by separation and detection of the protein species using liquid chromatography with a small particle size (1.8 μm) C(18) column and electrospray-time-of-flight mass spectrometry detection in the positive ionization mode. The fractionation of maize reference material containing different content of transgenic material (from 0 to 5% GM) led to five different fractions (albumins, globulins, zeins, zein-like glutelins, and glutelins), all of them containing different protein species (from 2 to 52 different species in each fraction). Some relevant differences in the quantity and types of protein species were observed in the different fractions of the reference material (with different GM contents) tested, thus revealing the potential use of the proposed approach for fast protein profiling and to detect tentative GMO markers in maize.