A multicenter community study on the efficacy of double-fortified salt

BACKGROUND: Iron and iodine deficiencies affect more than 30% of the world's population. Typical Indian diets contain adequate amounts of iron, but the bioavailability is poor. This serious limiting factor is caused by low intake of meat products rich in heme iron and intake of phytates in staple foods in the Indian diet, which inhibits iron absorption. OBJECTIVE: To test the stability of double-fortified salt (DFS) during storage and to assess its efficacy in improving the iron and iodine status of the communities. METHODS: The stability of both iodized salt and DFS during storage for a 2-year period was determined. The bioefficacy of DFS was assessed in communities covering three states of the country for a period of 1 year. This was a multicenter, single-blind trial covering seven clusters. The experimental group used DFS and the control group used iodized salt. The salts were used in all meals prepared for family members, but determination of hemoglobin by the cyanmethemoglobin method was performed in only two or three members per family, and not in children under 10 years of age (n = 393 and 436 in the experimental and control groups, respectively). The family size was usually four or five, with a male: female ratio of 1:1, consisting of two parents with two or three children. Hemoglobin was measured at baseline, 6 months (midpoint), and 12 months (endpoint). Urinary iodine was measured in only one cluster at baseline and endpoint. All the participants were dewormed at baseline, 6 months, and 12 months. RESULTS: The iron and iodine in the DFS were stable during storage for 2 years. Over a period of 1 year, there was an increase of 1.98 g/dL of hemoglobin in the experimental group and 0.77 g/dL of hemoglobin in the control group; the latter increase may have been due to deworming. The median urinary iodine changed from 200 microg/dL at baseline to 205 microg/dL at the end of the study in the experimental group and from 225 microg/dL to 220 microg/dL in the control group. There was a statistically significant (p < .05) improvement in the median urinary iodine status of subjects who were iodine deficient (urinary iodine < 100 microg/L) in both the experimental and the control groups, a result showing that DFS was as efficient as iodized salt in increasing urinary iodine from a deficient to sufficient status. There was a statistically significant increase (p < .05) in hemoglobin in all seven clusters in the experimental group compared with the control. CONCLUSIONS: The iron and iodine in the DFS are stable in storage for 2 years. The DFS has proved beneficial in the delivery of bioavailable iron and iodine.     

The origin of naturally occurring perchlorate: the role of atmospheric processes

Perchlorate, an iodide uptake inhibitor, is increasingly being detected in new places and new matrices. Perchlorate contamination has been attributed largelyto the manufacture and use of ammonium perchlorate (the oxidizer in solid fuel rockets) and/or the earlier use of Chilean nitrate as fertilizer (approximately 0.1% perchlorate). However, there are regions such as the southern high plains (Texas Panhandle) where there is no clear historical or current evidence of the extensive presence of rocket fuel or Chilean fertilizer sources. The occurrence of easily measurable concentrations of perchlorate in such places is difficult to understand. In the southern high plains groundwater, perchlorate is better correlated with iodate, known to be of atmospheric origin, compared to any other species. We show that perchlorate is readily formed by a variety of simulated atmospheric processes. For example, it is formed from chloride aerosol by electrical discharge and by exposing aqueous chloride to high concentrations of ozone. We report that perchlorate is present in many rain and snow samples. This strongly suggests that some perchlorate is formed in the atmosphere and a natural perchlorate background of atmospheric origin should exist.     

Studies on oxidation of benzo [a] pyrene by sunlight and ozone

The destruction of the carcinogen benzo[a]pyrene (BaP) by light is well known; laboratory workers are routinely advised to cover fluorescent lamps with yellow filters while treating samples containing BaP. However until recently the mechanism of oxidation by sunlight and ozone had not been studied in detail. Concentrations of benzo[a]pyrene in urban air are in the range of 5–10 μg/1000 m³. Oxidant concentrations (predominantly in the form of ozone) are reported to be in the range of 0.01 ppm (22 μg per m³). Thus a sampling system with a filter paper would filter about 22,000 μg of ozone passing through and collect about 5 μg of BaP for analysis. The effect of interactions of such large ozone concentrations with BaP deposited on the filter paper is reported; data for the oxidation rates for benzo[a]pyrene coated on quartz surface and exposed to ozone or sunlight are presented. The oxidation products were analysed by thin-layer chromatography and highpressure liquid chromatography. From about eight products detected in these experiments, three have been identified as quinones based on UV-absorption spectrometry and mass spectrometry. Oxidation rates as high as 100% per hour of exposure are observed when less than 0.1 μg of BaP is coated inside the quartz tubes and exposed to ozone or sunlight. Oxidation rates for benzo[a]pyrene (using tritiated BaP) were determined for two types of experimental conditions. In the first set, tritiated BaP was spotted onto a glass fibre paper and sampling continued for 24 h; the loss of BaP was found to be 88%. In the second set tritiated BaP was spotted at intervals of one hour, for eight hours, while sampling is being carried out and the loss of BaP during the period was estimated to be 50%.     

Effect of metal-ion-to-fuel ratio on the phase formation of bioceramic phosphates synthesized by self-propagating combustion

Synthetic calcium hydroxyapatite (HAP, Ca₁₀ (PO₄)₆ (OH)₂) is a well-known bioceramic material used in orthopedic and dental applications because of its excellent biocompatibility and bone-bonding ability due to its structural and compositional similarity to human bone. Here we report, for the first time, the synthesis of HAP by combustion employing tartaric acid as a fuel. Calcium nitrate is used as the source of calcium and diammonium hydrogen phosphate serves as the source of phosphate ions. Reaction processing parameters such as the pH, fuel-oxidant ratio and autoignition temperature are controlled and monitored. The products were characterized by powder x-ray diffraction, which revealed the formation of a hexagonal hydroxyapatite phase. Fourier transform infrared spectroscopy (FT-IR) spectra showed that the substitution of a carbonate ion occurs at the phosphate site. The morphology of the particles was imaged by scanning electron microscopy, which also revealed that the particles are of submicron size. Thermal analysis showed that the phase formation takes place at the time of combustion. Surface area and porosity analysis showed that the surface area is high and that the pores are of nanometer size. The mean grain size of the HAP powder, determined by the Debye–Scherrer formula, is in the range 20–30 nm. Chemical analyses to determine the Ca : P atomic ratio in synthesized ceramics were performed, and it was found to be 1 : 1.66.     

Mining the Web's link structure

The Web is a hypertext body of approximately 300 million pages that continues to grow at roughly a million pages per day. Page variation is more prodigious than the data's raw scale: taken as a whole, the set of Web pages lacks a unifying structure and shows far more authoring style and content variation than that seen in traditional text document collections. This level of complexity makes an “off-the-shelf” database management and information retrieval solution impossible. To date, index based search engines for the Web have been the primary tool by which users search for information. Such engines can build giant indices that let you quickly retrieve the set of all Web pages containing a given word or string. Experienced users can make effective use of such engines for tasks that can be solved by searching for tightly constrained key words and phrases. These search engines are, however, unsuited for a wide range of equally important tasks. In particular, a topic of any breadth will typically contain several thousand or million relevant Web pages. How then, from this sea of pages, should a search engine select the correct ones-those of most value to the user? Clever is a search engine that analyzes hyperlinks to uncover two types of pages: authorities, which provide the best source of information on a given topic; and hubs, which provide collections of links to authorities. We outline the thinking that went into Clever's design, report briefly on a study that compared Clever's performance to that of Yahoo and AltaVista, and examine how our system is being extended and updated     

Determination of substrate specificity for peptide deformylase through the screening of a combinatorial peptide library

Costimulatory molecules are critical in mediating Fas-dependent direct and bystander lysis. In direct lysis, the APC is the Fas-positive target. It presents Ag to the T cell, thereby activating the T cell. The activated T cell then up-regulates FasL, allowing it to kill the APC. In bystander lysis, the APC again induces FasL expression on the T cell, but the target is a third Fas-positive cell that may lack the appropriate MHC-restricting element to activate the T cell. This study shows that ICAM-1 and B7-1 can serve as important adhesion molecules in direct killing using CD4+ T cell effectors. In bystander killing, B7-1 appears to act as a signaling molecule as well. It has been demonstrated that lpr and gld mice are less susceptible to experimental allergic encephalomyelitis than their wild-type counterparts. In this study, we show that although microglia are poor targets of direct killing, they are capable of stimulating myelin basic protein-specific T cells to kill innocent Fas-positive targets. This presents a possible mechanism for the pathogenesis of experimental allergic encephalomyelitis.     

Assessment and modelling of the viability of a solar heating system for aquatic centres in southern Australia

Aquatic centres are large users of energy for water and space heating with an energy intensity which can be up to seven times that of a commercial office building in Australia. Much of the energy is used to heat water to relatively low temperatures, and therefore, solar energy technology is capable of providing this energy. In the residential sector, solar thermal systems for heating water and swimming pools are well-established. This is not the case for commercial swimming pools i.e. aquatic centres. In Australia, a program to encourage commercial pool operators to install solar systems was funded in the early 1980s. This paper has investigated the current use of and attitudes to solar systems in commercial pools through a survey of municipal pool operators in Victoria, southern Australia. The survey found that there has been very little increase in the use of solar energy and that perceived barriers to the use of the technology remain the same as they were nearly 30 years ago. Lack of roof area, poor payback periods and an inability of solar to meet pool heating needs are the most common misconceptions. The paper investigates these misconceptions by analysing the hot water needs of a large aquatic centre in Melbourne. It was found that there was sufficient roof area to accommodate a solar system that would provide a solar fraction of 0.60 and the simple payback period for a solar system using unglazed solar collectors was approximately 6.7 years at current gas prices. These are predicted to rise significantly making solar energy an even more attractive proposition for commercial pool heating. Failure of past incentives to stimulate the uptake of solar pool heating systems necessitates a revised approach. Key stakeholders (industry bodies, local governments, pool operators, manufacturers, relevant HVAC consultants and research organisations) all need to be involved in an exemplar project to demonstrate the technology’s viability for aquatic centres.     

Range map superresolution-inpainting,and reconstruction from sparse data

Range images often suffer from issues such as low resolution (LR) (for low-cost scanners) and presence of missing regions due to poor reflectivity, and occlusions. Another common problem (with high quality scanners) is that of long acquisition times. In this work, we propose two approaches to counter these shortcomings. Our first proposal which addresses the issues of low resolution as well as missing regions, is an integrated super-resolution (SR) and inpainting approach. We use multiple relatively-shifted LR range images, where the motion between the LR images serves as a cue for super-resolution. Our imaging model also accounts for missing regions to enable inpainting. Our framework models the high resolution (HR) range as a Markov random field (MRF), and uses inhomogeneous MRF priors to constrain the solution differently for inpainting and super-resolution. Our super-resolved and inpainted outputs show significant improvements over their LR/interpolated counterparts. Our second proposal addresses the issue of long acquisition times by facilitating reconstruction of range data from very sparse measurements. Our technique exploits a cue from segmentation of an optical image of the same scene, which constrains pixels in the same color segment to have similar range values. Our approach is able to reconstruct range images with as little as 10% data. We also study the performance of both the proposed approaches in a noisy scenario as well as in the presence of alignment errors.     

In situ TEM study of microplasticity and Bauschinger effect in nanocrystalline metals

In situ transmission electron microscopy straining experiments with concurrent macroscopic stress–strain measurements were performed to study the effect of microstructural heterogeneity on the deformation behavior of nanocrystalline metal films. In microstructurally heterogeneous gold films (mean grain size d_m = 70 nm) comprising randomly oriented grains, dislocation activity is confined to relatively larger grains, with smaller grains deforming elastically, even at applied strains approaching 1.2%. This extended microplasticity leads to build-up of internal stresses, inducing a large Bauschinger effect during unloading. Microstructurally heterogeneous aluminum films (d_m = 140 nm) also show similar behavior. In contrast, microstructurally homogeneous aluminum films comprising mainly two grain families, both favorably oriented for dislocation glide, show limited microplastic deformation and minimal Bauschinger effect despite having a comparable mean grain size (d_m = 120 nm). A simple model is proposed to describe these observations. Overall, our results emphasize the need to consider both microstructural size and heterogeneity in modeling the mechanical behavior of nanocrystalline metals.     

Surface characterization of passive film formed on nitrogen ion implanted Ti-6Al-4V and Ti-6Al-7Nb alloys using SIMS

The aim of this paper is to study the effect of N⁺ ion implantation on corrosion and phase formation on the implanted surfaces of Ti-6Al-4V and Ti-6Al-7Nb alloys. Nitrogen ion was implanted on Ti-6Al-4V and Ti-6Al-7Nb alloys at an energy of 70 and 100 keV, respectively using a 150 keV accelerator at different doses ranging from 5 × 10¹⁵ to 2.5 × 10¹⁷ ions/cm². Electrochemical studies have been carried out in Ringer’s solution in order to determine the optimum dose that can give good corrosion resistance in a simulated body fluid condition. The implanted surfaces of such modified doses were electrochemically passivated at 1.0 V for an hour. Secondary ion mass spectroscopy was used to study and characterize titanium oxide and titanium nitride layers produced on implanted surface and to correlate them with the corrosion resistance. The nature of the passive film of the implanted-passivated specimen was compared with the unimplanted-passivated as well as as-implanted specimens.