Corrosion of reinforcement bars embedded in structures near coastal areas is a serious problem and has been attributed to many premature distresses of structures. The passivity imparted by the ...alkalinity of the cement to reinforcement steel surface becomes ineffective when chloride concentration at the steel surface exceeds a critical threshold value. Under such a situation, the total loss of the steel thickness per unit area is negligibly small in comparison to penetration rate at certain susceptible part of the reinforcement bars. As a result of increase in stress intensity factor at the tip of localized pits formed on the surface of rebars, the tensile strength of the concrete structures which is mainly imparted by the steel reinforcement bars, is adversely affected and results in collapse of structures. Many techniques have been developed to control the corrosion problems associated with rebars. These include use of corrosion resistant alloys, corrosion inhibitors, cathodic protection and use of organic/metallic coatings on surface of steel bars. Amongst these techniques, the applications of surface coatings appear an effective and economical method to control corrosion of steel rebars. However, the efficacy and mechanism of their protective action are still matter of controversy and subject matter of studies all over the world. The present work is in continuation of our earlier studies published in different scientific journals where the above aspects had been addressed. This paper incorporates experimental results and literature review in understanding the corrosion and remedial measures to control the deterioration of reinforcement steel bars by modification in their chemistry and application of surface coatings. A brief historical background is given on development of reinforcement concrete structures. Various types of reinforcement bars used in construction industries and their merits and demerits are described. It has been established by the experimental proofs that the current scenario of protecting steel rebars used in chloride contaminated concrete, is not at all satisfactory. Amongst the protective coatings, metallic coated rebars appear to be more effective than organic based coatings. Causes and mechanism of deterioration of coated and bare steel rebars are discussed by providing experimental evidences.
In general, we know that small intestine is mostly the site for drug absorption but in some cases the drug needs to be targeted to some other sites for absorption due to various factors like any ...disease condition, degradation related situations, for sustained release of drugs etc. Colon targeted drug delivery is a relatively new concept for the absorption of drugs as it offers near neutral pH. Also it offers long residence time, thereby increasing the drug absorption. The nature of food and enzymes does not affect the drug absorption. Colon has proved to be a site for the absorption of poorly soluble drugs. For the successful targeting of drugs to colon the dosage form should be designed such that it prevents the drug release in upper GIT and releasing it in the colonic region. This review article comprises of the various aspects of colon targeting which we should know before experimenting the technique and their IVIVC using recent evaluation models through x-ray imaging and gamma-scintigrapy.
Engineering properties of sands mainly depend on the integrity of the particles, which in turn has a strong bearing on their crushing strength. Seven different Aegean sands were tested for ...mineralogy, particle shape, size and specific gravity and the influence of aspect ratio, particle composition, particle shape and size on the crushing strength was examined. As the Aegean sands have a small range of sphericity and roundness, crushing strength tests were also performed on five Anatolian sands. A multiple regression analysis was carried out and an equation proposed to determine the crushing strength value of the Aegean sands. The computed values were found to be in good agreement with those obtained from the experimental investigations. It is concluded that the equation is sufficiently accurate to be a useful, time- and cost-effective way of obtaining crushing strength estimations at the preliminary stage of site investigations.
BackgroundFailure to follow-up abnormal test results can lead to patient harm.ObjectivesWe created and validated electronic trigger algorithms that analyzed electronic health record (EHR) data from a ...large Veterans Affairs (VA) network to identify patients with potential delays in diagnostic evaluation for multiple cancers.MethodsWe developed five trigger algorithms to detect delays in diagnostic evaluation of possible bladder, breast, colorectal, hepatocellular, and lung cancer. Each used structured clinical data to identify patient records with red-flags (abnormal test results warranting further diagnostic evaluation). Red-flags included high-grade hematuria (>50 red blood cells/high powered field; bladder cancer trigger), abnormal mammograms (breast cancer trigger), iron deficiency anemia or positive fecal immunochemical tests (colorectal cancer trigger), elevated alpha-fetoprotein (hepatocellular trigger), or chest imaging flagged as suspicious for malignancy (lung cancer trigger). Algorithms excluded records where follow-up was unnecessary (e.g., hospice patient) and records where follow-up was documented within 30 (lung cancer trigger) or 60 days (all others). We validated triggers by applying them retrospectively to EHR data (see table 1 for timeframes and sample sizes).Abstract IHI ID 04 Table 1 Cancer Trigger Unique Patients with Trigger Positives Unique Patients Seen Timeframe PPV %(95% CI) NPV %(95% CI) Extrapolated Sensitivity % (95% CI) Extrapolated Specificity % (95% CI) Estimated Number of Diagnostic Delays Found per Year Bladder495310,331Jan 2012–Dec 201458.0 (53.0–62.9)97.0 (90.8–99.2)64.1 (59.4–68.5)96.2 (95.6–96.6)95.7Breast552365,686Jan 2010–May 201570.8 (66.0–75.1)93.0 (85.6–96.9)76.8 (72.7–80.4)90.8 (89.2–92.1)72.2Colorectal1,073245,158Jan 2013–Dec 201356.0 (51.0–61.0)88.0 (79.6–93.4)68.6 (65.4–71.6)81.1 (79.5–82.6)600.9Hepatocellular130333,828Jan 2011–Dec 201482.3 (74.4–88.2)98.0 (92.3–99.7)89.1 (81.8–93.8)96.5 (94.8–97.7)26.7Lung655208,633Jan 2012–Dec 201260.5 (55.5–65.3)97.0 (90.8–99.2)91.7 (88.6–94.1)81.7 (79.6–83.7)396.3 1191.8 *CI=Confidence IntervalResultsThe five triggers yielded PPVs ranging from 56.0–82.3%, NPVs ranging from 88.0–98.0%, sensitivity from 64.1–91.7%, and specificity from 81.1–96.5% (see table 1). We estimated that these triggers have the potential to identify 1192 diagnostic errors in the VA network studied per year.ConclusionsOur triggers have potential to identify large numbers of patients experiencing delays in diagnostic evaluation. Implementing prospective electronic trigger-based measurement systems using these algorithms could support health systems in reducing delays in delays in cancer diagnosis.
We estimated the Curie depth using magnetic anomalies in the tectonically complex central Indian shield. The modified centroid method for the scaling distribution of sources is applied to ...aeromagnetic data and satellite magnetic data (EMAG2) to estimate the Curie depths. We selected 80% overlapping with a window length of 300 × 300 km2 for Curie depth estimation. The estimated Curie depths are 22–46 km being shallower in the Bastar craton, northern end of the Aravalli-Delhi fold belt, and eastern part of Central Indian tectonic zone in the Deccan Volcanic Province. Deeper Curie depths are found in the eastern parts of the Aravalli-Delhi fold belt, Deccan Volcanic Province to the south of Tapti basin, parts of the Ganga and Vindhyan basins. The heat flow values estimated from the Curie depths vary from 30 to 90 mW/m2 being higher are in the northern part covering the Aravalli-Delhi fold belt and the Ganga basin and low heat flow values in the remaining study region. The computed thermal lithospheric thickness ranges 62–120 km, being 62 km thin in the Vindhyan basin, 68 km in the Aravalli-Delhi fold belt, and 73 km in the Bastar craton. We noticed a relatively thick thermal lithospheric thickness of 99 km beneath the foreland Ganga basin and 100 km in the Bundelkhand craton. The thermal lithosphere beneath the Deccan Volcanic Province is found to have a thickness ~ 120 km , which is interpreted as due to the rapid cooling of the lithosphere after Reúnion plume activity. Probably, the plume activities in the past could have modified the thermal lithospheric structure beneath central India. The upper mantle in the Deccan Volcanic Province to the south of the Tapti basin and the Aravalli-Delhi fold belt show magnetic character.
•Curie depth (22–46 km), heat flow (30–90 mW/m2) are estimated using EMAG2 data.•Deep Curie depth in the DVP is an imprint of intense cooling after plume activity.•Heat flow is high in parts of the Bastar, Aravalli-Delhi fold belt, Vindhyan basin.•Upper mantle is magnetic in parts of Aravalli-Delhi fold belt, Vindhyan basin, DVP.•Thermal lithospheric thickness varies from 62 to 120 km beneath central India.
This paper investigates the properties of thin films of chromium-doped Ni80Fe20 (Permalloy) that could potentially be useful in future low-power magnetic memory technologies. The addition of chromium ...reduces the saturation magnetization, Ms, which is useful for low-energy switching, but does not significantly degrade the excellent switching properties of the host material even down to 10 K, the lowest temperature measured, in films as thin as 2.5 nm. As an example, an alloy film composed of 15% chromium and 85% Ni80Fe20 has an Ms just over half that of pure Ni80Fe20, with a coercivity Hc less than 4 Oe, an anisotropy field Hk less than 1 Oe, and an easy-axis remanent squareness Mr/Ms of 0.9 (where Mr is the remanent magnetization). Magnetodynamical measurements using a pulsed inductive microwave magnetometer showed that the average Landau Lifshitz damping λ was relatively constant with changing Cr content, but increased significantly for thinner films (λ ≈150 MHz for 11 nm, λ ≈250 MHz for 2.5 nm), and at low bias fields likely due to increased magnetic dispersion. Density functional theory calculations show that chromium reduces Ms by entering the lattice antiferromagnetically; it also increases scattering in the majority spin channel, while adding almost insignificant scattering to the minority channel.
We report an excellent photoresponsive controlled release formulation based on a coumarin copolymer for pesticide 2,4-D. In the present work, acrylate and polyethylene glycol (PEG) based coumarin ...photoresponsive polymers were synthesised. The newly synthesised coumarin based polymers exhibited dual functionalities, namely as “fluorophores” and “phototriggers” for the controlled release of pesticide 2,4-D. The fluorescence properties of coumarin based polymers helped us to monitor the release of 2,4-D from the polymeric formulation. Release of the pesticide by coumarin based polymers was achieved on exposure to UV light. TGA results indicated that the coumarin polymer encapsulated pesticide has a good thermal stability compared to the free pesticide 2,4-D. A further leaching experiment also showed that the polymer encapsulated pesticide leaches slowly compared to the free pesticide 2,4-D. Bioassay studies in a plant suggest that the coumarin polymer encapsulated pesticide efficiently delivered 2,4-D inside the plant tissues (pumpkin plant Cucurbita maxima ) improving its herbicidal activity. Our results indicated that use of a fluorescent coumarin polymer based delivery device for controlled release of pesticide by light holds great interest for field application.
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