The influence of dietary iron on zinc in rat

Cortical bone remodeling rates for rib samples from three archaeological populations and a modern autopsy sample were determined using an algorithm developed by Frost (Frost [1987a] Calcif. Tissue Res. 3:211-237). When plotted against the relative antiquities for population samples, histomorphometric variables; i.e., activation frequency (mu rc), net bone formation (netVf,r,t), and mean annual bone formation rate (Vf,r,t), exhibit a concordant trend of increased cortical bone remodeling activity levels over time. Two intensive foraging populations, Windover and Gibson, are similar for all bone remodeling parameters and have the lowest remodeling activity levels among the samples. The more recent Ledders sample, which is reported to practice agricultural subsistence, is consistently intermediate between these and a modern autopsy sample. Although there appear to be differences in bone formation rates among the populations it is concluded that these differences cannot be attributed to differences in bone remodeling rates among the populations, but rather are reflecting different effective ages of adult compacta for their ribs. These findings suggest that the earlier populations, particularly Windsor and Gibson, appear to have reached skeletal maturity at an older age than observed for modern.     

The importance of structural and gel fractions in determining shear sensitivity of sludge.

Shear sensitivity measurements with variation of ingredients in a synthetic sludge can be related to biosolids' structural properties and particulate amount. The shear sensitivity is primarily controlled by the gel fraction, with alginate and the associated cations increasing the gel-like behavior. However the effect of particulate fraction on shear sensitivity should also be taken into account. Shear sensitivity is thus a complex parameter including two types of response: the resistance to dispersed mass concentration into centrate, and the maintenance of desired strength while the solids concentration increases in the shear field.     

Calcitonin treatment in reflex sympathetic dystrophy: a preliminary study

Reflex sympathetic dystrophy is one of the important complications effecting the rehabilitation programmes of hemiplegic patients in a negative manner by causing pain and function loss. In this study, the aim was to investigate the effects of salmon calcitonin treatment in reflex sympathetic dystrophy that develops in hemiplegia. Forty-one patients with hemiplegia resulting from cerebrovascular events and stage 1-2 reflex sympathetic dystrophy were included in the study. Salmon calcitonin, 1 x 100 IU/day intramuscularly for 4 weeks, was administered to 25 of these patients (calcitonin group) to the other 16 patients physiological saline, 1 ml/day intramuscularly for 4 weeks, was administered (control group). At the end of the fourth week of treatment the pain score of the calcitonin group was significantly lower than that of the control group. Shoulder abduction and external rotation, wrist flexion and metacarpophalangeal extension of the calcitonin group were found to be significantly better than those of the control group. In the calcitonin group the significant decrease in pain and tenderness resulted in improvement of range of motion and motor functions.     

Poly(Acrylamide-Sepiolite) Composite Hydrogels: Preparation, Swelling and Dye Adsorption Properties

Summary Polymer-clay hydrogel composite was prepared on the basis of polyacrylamide (PAAm) gel containing the clay mineral sepiolite. The properties of swelling and dye adsorption of poly(acrylamide-sepiolite) (AAm/Sep) composite hydrogel were investigated. The parameters of swelling and diffusion in water and dye solutions were calculated for the AAm and AAm/Sep hydrogels. It was found that the equilibrium swelling degree of obtained composite higher than that of AAm gel. Spectroscopic analysis of composite and composite-dye systems was done with FT-IR method. Adsorption of monovalent cationic dyes such as Basic Blue 12 (BB-12) Basic Blue 9 (BB-9), and Basic Violet 1 (BV-1), was studied on the composite. In the adsorption experiments, S (Sigmoidal) type for composite gel adsorption isotherms in the Giles classification system was found. Adsorption studies indicated that the amounts of adsorbed dyes on the AAm/Sep composite hydrogel were increased with following order; BB-12 > BB-9 > BV-1. The composite hydrogel may be considered as good candidate for environmental application to retain more water and dyes.     

Nonlinear L2-by-3 transform for PAPR reduction in OFDM systems

Orthogonal frequency division multiplexing (OFDM), the multicarrier modulation technique with high bandwidth efficiency and robustness against multipath fading, is used in several high-speed broadband communication systems including digital video broadcasting (DVB), digital audio broadcasting (DAB), asymmetric digital subscriber line (ADSL), wireless local area network (WLAN IEEE 802.11a,g), high performance radio local area network (HIPERLAN 2), and worldwide interoperability for microwave access (WiMAX IEEE 802.16). However, the transmit signal in OFDM system has a high peak-to-average power ratio (PAPR), one of the major drawbacks of multicarrier transmission, and therefore high dynamic range is required in both the digital to analog converter (DAC) and the power amplifier (PA) for proper operation. Otherwise, the nonlinearities of PA cause out-of-band distortion and increase in bit error rate (BER). Therefore, the reduction in PAPR in OFDM system is desirable in order to obtain power efficiency and increase BER performance. In this paper, a new parametric PAPR reduction technique, L₂-by-3 transform from sliding norm transform (SNT) family is proposed. Based on its parameter, a significant PAPR reduction is obtained. This paper presents the analysis of power saving and computational complexity of the proposed method L₂-by-3 and comparison to two other methods; selected mapping and partial transmit sequence.     

A fuzzy long-term investment planning model for a GenCo in a hybrid electricity market considering climate change impacts

We study the long-term generation capacity investment problem of an independent power generation company (GenCo) that functions in an environment where GenCos perform business with both bilateral contracts (BC) and transactions in the day-ahead market (DAM). A fuzzy mixed integer linear programming model with a fuzzy objective and fuzzy constraints is developed to incorporate the impacts of imprecision/uncertainty in the economic environment on the calculation of the optimal value of the GenCo’s objective function. In formulating the fuzzy objective function we also include the potential impacts of climate change on the energy output of hydroelectric power plants. In addition to formulating and solving the capacity planning/investment problem, we also performed scenario-based (sensitivity) analysis to explore how investment decisions of the GenCos change when fuzziness (tolerance) in the maximum energy output of hydroelectric units and/or drought expectation increases. The proposed model is novel and investigates the effects of factors like drought expectations of climate changes, hydroelectric power plant investments, and other power generation technology investment options.     

Electricity restructuring in Turkey and the share of wind energy production

This paper presents the current status of Turkey's electricity power sector, efforts for introducing competition in the Turkey's power industry, and concerns with the restructuring in Turkey. Turkey include long-term high-cost agreements, low quality of power, and therefore restrictions for synchronization with UCTE network, increase in the reliance on imported natural gas, and the urgent need for highly qualified staff that would be capable of fast and reliable implementation of ongoing reforms in the electricity sector. The contribution of the exploiting wind energy potential in Turkey to reconstruction of Turkey electricity structure is investigated. The strong development of wind energy in Turkey is expected to continue in the coming years.     

Synthesis and proton conductivity studies of 5‐aminotetrazole‐doped sulfonated polymer electrolyte membranes

This work reports the preparation and characterization of a new anhydrous proton conducting membrane based on poly(vinyl alcohol) (PVA), sulfosuccinic acid (SSA), and 5‐aminotetrazole (ATet) at various stoichiometric ratios. The proton conductivities of membranes were investigated as a function of ATet composition, SSA composition, and temperature. New anhydrous proton conducting membranes were characterized by infrared spectra, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), methanol permeability, and impedance measurements for proton conductivity. TGA showed that the samples were thermally stable up to 150°C. DSC results illustrated the homogeneity of the materials. Mechanical analysis showed that the storage modulus of the PVA–SSA–ATet blend polymer membranes decreased with increasing ATet content. The membranes with higher tetrazole content, or higher acid doping level presented the higher proton conductivity. PVA–SSA–ATet4 can exhibit an anhydrous proton conductivity of 1.7 × 10⁻³ S/cm at 130°C and the proton conductivity increased with increasing temperature and acid doping level. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Electrocatalytic oxidation of sodium borohydride on metal ad-atom modified Au(111) single crystal electrodes in alkaline solution

The electrochemical oxidation of borohydride was investigated by using various ad-atom modified Au(111) electrodes in alkaline media in comparison to Au(111) single crystal, polycrystalline Au, Pt and Zn electrodes. The catalytic activity of gold towards borohydride oxidation has tended to increase in more alkaline media as reflected in the oxidation peak in the concentration range of NaOH (0.01-2.0 M) studied. Additional shift on the oxidation peak potential of borohydride on Pt and Zn ad-atom modified Au(111) electrodes was observed for both ad-atom modified electrodes to more negative potentials compared to that of bare electrodes, respectively. The ad-atom modified Au(111) electrodes surfaces do not only provide a superior electrical contact, but also accelerates electron transfer as proven by the increase in peak current and positive shift in the peak potential.     

REACTIONS OF METHOXY-SUBSTITUTED AROMATIC COAL MOOELS IN SUPERCRITICAL SOLVENTS

Abstract

Reactions of α- and β-methoxy naphthalene and anisole in supercritical benzene and toluene were studied at 420 °C and 3.9-4.4 MPa pressure. The decomposition of these lower rank coal related model compounds in both solvents was found to obey the first order rate law. While naphthols were present in the reaction mixture of methoxy naphthalenes, phenol and cresoles were present in that of anisole. In addition to these products, diphenyl or dibenzyl was also present in the reaction mixture of supercritical benzene or toluene, respectively. The reactions between models and solvents might be explained by free radical and intermolecular rearrangement reaction pathways.