Memory Effects in the Charge Response of Lightly Doped La2?x Sr x CuO4

The in-plane magnetoresistance (MR) of a single crystal La_1.97Sr_0.03CuO₄ has been studied at low temperatures T using several experimental protocols. At T well below the spin-glass transition temperature, the MR becomes positive and exhibits several glassy features, such as history dependence, memory, and hysteresis. These observations are qualitatively similar to the previously reported behavior of the out-of-plane resistance. The results suggest that the memory effects in the MR are related to the onset of glassiness in the dynamics of doped holes.     

Surface modification of macroporous glycidyl methacrylate based copolymers for selective sorption of heavy metals

Two samples of macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), poly(GMA-co-EGDMA), were synthesized by suspension copolymerization and modified with amines. Initial poly(GMA-co-EGDMA), and the samples modified with ethylene diamine [poly(GMA-co-EGDMA)-en], diethylene triamine [poly(GMA-co-EGDMA)-deta] and triethylene tetramine [poly(GMA-co-EGDMA)-teta], were characterized by mercury porosimetry, FTIR spectroscopy and elemental analysis. The most pronounced increase of specific surface area (75%) was observed for poly(GMA-co-EGDMA)-teta sample with smaller particles (D < 150 μm). The Cu(II) sorption was rapid, depending on porosity of amino-functionalized samples and ligand type. For poly(GMA-co-EGDMA)-deta and poly(GMA-co-EGDMA)-teta sorption half time required to reach 50% of total sorption capacity, t _1/2, were around 3 min. Sorption capacities for Cu(II), Co(II), Cd(II) and Ni(II) as well as for Cr(VI), Co(II), Cd(II) and Ni(II) ions were determined under competitive conditions as a function of pH, ligand type and porosity at room temperature. The results indicate selectivity of poly(GMA-co-EGDMA)-deta for Cu(II) over Cd(II) of 3:1 and for Cu(II) over Ni(II) and Co(II) of 6:1. The decrease in particle size of poly(GMA-co-EGDMA)-teta caused the increase of sorption capacities for all metal ions. At pH 1.8 the selectivity of poly(GMA-co-EGDMA)-teta with smaller particles for Cr(VI) over Ni(II), Co(II) and Cd(II) ions was 8.5:1.     

Self-assembled polyaniline 12-tungstophosphate micro/nanostructures

Polyaniline (PANI) micro/nanostructures were synthesized by the external-template-free oxidative polymerization of aniline in aqueous solution of 12-tungstophosphoric acid (WPA), using ammonium peroxydisulfate (APS) as an oxidant and starting the oxidation of aniline from slightly acidic media (pH 5.4–5.9). The effect of the initial weight ratio of WPA to aniline on molecular structure, morphology, and physicochemical properties of polyaniline 12-tungstophosphate (PANI-WPA) was investigated by FTIR, Raman and inductively coupled plasma optical emission (ICP-OES) spectroscopies, elemental analysis, X-ray powder diffraction (XRPD), scanning and transmission electron microscopies (SEM and TEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and conductivity measurements. The morphological change of polymerization products during a single polymerization process, from non-conducting submicro-/microspherical oligoaniline intermediates to semiconducting PANI-WPA consisted of self-assembled nanotubes and/or nanorods co-existing with submicro-/microspheres, has been revealed by SEM and TEM. The average diameter of nanorods in PANI-WPA samples decreased with increasing the initial WPA/aniline weight ratio. The incorporation of 12-tungstophosphate counter-ions into PANI matrix has been proved by FTIR, Raman and ICP-OES spectroscopies, TGA and DTA analysis. Electrical conductivity of PANI-WPA increased in the range (2.5–5.3) × 10^?3 S cm^?1 with the increase of the initial WPA/aniline weight ratio. The presence of branched structures and phenazine units besides the ordinary paramagnetic and diamagnetic emeraldine salt structural features in PANI-WPA was proved by FTIR and Raman spectroscopies.     

Clutter Reduction and Detection of Minelike Objects in Ground Penetrating Radar Data Using Wavelets

Ground Penetrating Radar (GPR) signatures of shallowly buried landmines are normally obscured by a strong background signal comprised of the reflections from the ground surface and the antenna crosstalk. Based on the notion that buried landmine produces an anomaly in the soil dielectric an automated procedure has been developed which detects soil dieletric anomalies of the size comparable to the size of landmine in GPR data and enhances the signatures of such anomalies. A local background estimate is computed and a soil dielectric anomaly is detected at the spatial position where a change from the estimated background signal occurs. A translation invariant wavelet packet decomposition is applied for detection. The computation takes place in a running window which allows for the algorithm to adapt to the variations in ground conditions and antenna height. The technique was tested using a number of minelike targets buried in several different soil environments and the testing results are presented.     

Phase transformations in the ternary Ag–Ga–Sb system

Phase diagram of the Ag–Ga–Sb ternary system was extrapolated using calculation of phase diagrams (CALPHAD) method. Phase transition temperatures of the alloys with compositions along three vertical sections with constant molar ratios Ga/Sb = 1, Ag/Ga = 1 and Ag/Sb = 1 were measured using differential scanning calorimetry (DSC). Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) was used for identification of phases in equilibrated samples. Experimental results were compared with thermodynamic prediction.     

Poverty and environmental impacts of electricity price reforms in Montenegro

The creation of the Energy Community of South Eastern Europe in 2005 committed countries in South Eastern Europe to liberalize their energy markets in accordance to EU regulations. The Government of Montenegro is thus in the process of reforming its energy sector, which includes an electricity tariff reform. This paper analyzes the environmental and social impacts of an increase in residential electricity tariffs contemplated – which is expected to range anywhere from 40 to over 100% increase. As this analysis shows, such a significant price rise will impose a heavy burden on the poor households and it may adversely affect the environment. In an ex ante investigation of the welfare impact of this price increase on households in Montenegro, we show that the anticipated price increase will result in a very significant increase in households' energy expenditures. A simulation of alternative policy measures analyzes the impact of different tariff levels and structures, focusing on the poor and vulnerable households. Higher electricity prices could also significantly increase the proportion of households using fuelwood for space heating. Thus the level of fuelwood consumption should be carefully monitored under the electricity tariff reforms and the Government of Montenegro should combine the tariff reforms with a carefully evaluated set of policy measures to mitigate the effect of the electricity price increase on the poor.     

Intermittent hemodialysis treatment in cefepime‐induced neurotoxicity: Case report,pharmacokinetic modeling,and review of the literature

Cefepime is a broad‐spectrum cephalosporin indicated for in‐hospital treatment of severe infections. Acute neurotoxicity, an increasingly recognized adverse effect of this drug in an overdose, predominantly affects patients with reduced renal function. Although dialytic approaches have been advocated to treat this condition, their role in this indication remains unclear. We report the case of an 88‐year‐old female patient with impaired renal function who developed life‐threatening neurologic symptoms during cefepime therapy. She was treated with two intermittent 3‐hour high‐flux, high‐efficiency hemodialysis sessions. Serial pre‐, post‐, and peridialytic (pre‐ and postfilter) serum cefepime concentrations were measured. Pharmacokinetic modeling showed that this dialytic strategy allowed for serum cefepime concentrations to return to the estimated nontoxic range 15 hours earlier than would have been the case without an intervention. The patient made a full clinical recovery over the next 48 hours. We conclude that at least 1 session of intermittent hemodialysis may shorten the time to return to the nontoxic range in severe clinically patent intoxication. It should be considered early in its clinical course pending chemical confirmation, even in frail elderly patients. Careful dosage adjustment and a high index of suspicion are essential in this population.     

Magnetotransport at the LTO-LTT Structural Transition in La<Subscript>1.48</Subscript>Nd<Subscript>0.4</Subscript>Sr<Subscript>0.12</Subscript>CuO<Subscript>4</Subscript>

Magnetoresistance (MR) was measured in a La_1.48Nd_0.4Sr_0.12CuO₄ single crystal in perpendicular magnetic fields H up to 9 T in the region of the structural transition from the low-temperature orthorhombic (LTO) to low-temperature tetragonal (LTT) phase. The hysteretic MR exhibits discrete jumps or avalanches only when the transition is approached from the LTT phase, and only during the first field sweep. The properties of the hysteresis are found to be independent of the field driving rate. The results are consistent with the presence of magnetostructural domains coupled with the charge degrees of freedom.