פרסומים

We performed broadband dielectric spectroscopy (BDS) measurements of glycerol-water mixture from 0% to 100 mol% glycerol concentrations with 5 mol% interval in a frequency range from 1 Hz to 250 Nfflz at temperatures between 173 K and 323 K. Differential scanning calorimetry (DSC) measurements from 138 to 313 K were also provided. The experimental results obtained for the glycerol-rich mixtures in terms of dielectric loss ``master plots'' suggest that the main dielectric relaxation process, the high frequency ``excess wing (EW)'' and dc-conductivity, all follow the same temperature dependence. This result indicates that all of these processes have the same origin. A new phenomenological relationship for complex dielectric permittivity is proposed in order to provide a comprehensive fitting of the experimental data covering conductivity, main process and EW. Experimental data in water-rich mixtures show the existence of a critical concentration of 40 mol% of glycerol that relates to the number of hydrogen bonds of glycerol and of water molecules. Below this concentration, water cooperative domains appeared, coexisting with glycerol cooperative domains. Furthermore in the water-rich region, ice particles appeared that led to three relaxation processes due to ice, the mesoscopic glycerol-water domain, and water on the interface between former two. The ice nanocrystals showed broad melting behavior (BMB) with increasing temperature that was explained by kinetic description of the water-exchange rates between water molecules in the mesoscopic domain, ice nanocrystals, and the interfacial water. The mole fractions of these water states were determined, and the minimum number of water molecules that can gain bulk ice properties was estimated.

Sulfur mustard (SM) is powerful alkylator and highly cytotoxic blisterogen in both humans and animals. This study in male guinea pigs shows that, at an early stage (5 h) after SM exposure, a marked increase occurred in epithelial nuclear vacuolation, epidermal thickening, and dermal acute inflammation. Topical iodine treatment reduced the severity of these parameters. The rate of DNA synthesis expressed by incorporation of bromodeoxyuridine was reduced upon topical treatment with iodine only or SM only by 46 and 72%, respectively. Iodine treatment following SM exposure exerted an effect similar to that of SM only, indicating that DNA synthesis is not directly involved in the mechanism of action of iodine-induced protection.

This study examines the desired parameters for the institution of an earned income tax credit (EITC) – a subsidy for low wage earners – in Israel. The goal of the system would be to encourage individuals with low earning potential to enter the labor market and to reduce poverty among households that include wage earners. The combination of data from consecutive Labor Force and Household Incomes Surveys (using the repeated sampling feature of the Labor Force Surveys) enabled us to evaluate the sensitivity of entry into the labor force and employment, and of exit from employment to wage changes among individuals in various income groups. The estimated elasticities of entry and exit with respect to the wage were used to evaluate the effect of various policy scenarios on employment and poverty. The institution of an EITC system in the basic policy scenario, which grants benefits at income levels of 1,000–5,000 shekels, increases the number of participants in the labor force by about 13,000 which represents 0.5 percent of the working age population. At the same time, it was found that the cost of attracting a new worker was high, that most of the effect on employment was achieved in households not within the weaker segments of the population and that the program’s effectiveness in reducing poverty was relatively low. A more focused policy, which conditions benefits on family composition and household income, is less effective in increasing employment but much more efficient in reducing poverty. This policy would raise 18 percent of poor working families above the poverty line. The budgetary cost of the basic program is NIS 2.7 billion per-annum while the cost of the focused program is NIS 1.3 billion.  

The difference in the heterogeneous binding of Mg(2+), Ca(2+) and Sr(2+) ions by 1-thioglycerol (TG) and 1,4-dithiothreitol (DTT) spontaneously adsorbed monolayers on Au has been studied following the changes in the double layer capacity. A mathematical treatment, based on calculating the electrochemical potential difference at the monolayer-electrolyte interface, has followed our recent work which dealt with the acid-base equilibrium at the interface as a means of calculating the pK of ionizable SAMs and their binding with Cd(2+). Experimentally, spontaneously adsorbed monolayers of TG and DTT were assembled on Au surfaces and studied by impedance spectroscopy and alternating current voltammetry (ACV). The capacity was measured for each of the modified surfaces at increasing concentrations of the divalent metal ions separately. The goal of this study has been to examine the effect of metal ion binding by similar ligands that are differently attached onto the surface. TG and DTT monolayers differ in their flexibility, which is a result of their attachment to the surface through one and two arms, respectively. The general trend of the apparent heterogeneous association constants of the divalent metal ions, which were calculated from the capacity measurements, was substantially different from the classical Irving-Williams series that is applicable to homogeneous systems. This difference could be nicely explained by the reduction of the degree of freedom and flexibility of the attached ligands.[on SciFinder (R)]

The difference in the heterogeneous binding of Mg2+, Ca2+ and Sr2+ ions by 1-thioglycerol (TG) and 1,4-dithiothreitol (DTT) spontaneously adsorbed monolayers on Au has been studied following the changes in the double layer capacity. A math. treatment, based on calcg. the electrochem. p.d. at the monolayer-electrolyte interface, has followed our recent work1 which dealt with the acid-base equil. at the interface as a means of calcg. the pK of ionizable SAMs and their binding with Cd2+. Exptl., spontaneously adsorbed monolayers of TG and DTT were assembled on Au surfaces and studied by impedance spectroscopy and a.c. voltammetry (ACV). The capacity was measured for each of the modified surfaces at increasing concns. of the divalent metal ions sep. The goal of this study has been to examine the effect of metal ion binding by similar ligands that are differently attached onto the surface. TG and DTT monolayers differ in their flexibility, which is a result of their attachment to the surface through one and two arms, resp. The general trend of the apparent heterogeneous assocn. consts. of the divalent metal ions, which were calcd. from the capacity measurements, was substantially different from the classical Irving-Williams series2-4 that is applicable to homogeneous systems. This difference could be nicely explained by the redn. of the degree of freedom and flexibility of the attached ligands. [on SciFinder(R)]

The g(44) grating is an electroholographic transmission grating in which the applied field is perpendicular to both the grating vector and the wave vector of the incident beam. It is argued that in this configuration the incident beam traverses through a periodically rotating index ellipsoid. It is shown that in the g(44) configuration the Bragg condition is fulfilled for a specific value of the applied field and for a diffracting beam polarization that is perpendicular to that of the incident beam. Consequently, the g(44) grating can be used as an electrically controlled filter. Tunability of 7 nm is demonstrated in a 2mm thick grating.

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