Determination of residues of trichlorfon and dimethoate on guava using HPLC

A supervised trial was conducted in guava orchards during 2001 and 2002 to study residue dissipation rates of two organophos insecticides, trichlorfon and dimethoate at Kohat, NWFP, Pakistan. The insecticides were sprayed at recommended doses of 80 and 120 g a.i./100 l water on the fruits of guava when the fruits were semi ripe. The treated guava fruits were randomly sampled in triplicates (2 kg per field replicate) at 0, 3, 7, 14, and 21 days intervals after insecticide application. The samples were extracted in ethyl acetate and were cleaned up through Florisil column with ethyl acetate as eluent. The cleaned up extracts were analyzed for residues by HPLC method. The residues were found to have half-lives of 2.8–3.3 days for dimethoate and 1.7–2.0 days for trichlorfon. Based on the dissipation pattern of the insecticide residues in relation to their respective prescribed maximum residue limits, withholding periods of 3 and 9 days are suggested for guava after treatment with dimethoate and trichlorfon.     

Modulating response of Zea mays to induced salinity stress through application of nitrate mediated silver nanoparticles and indole acetic acid

Nanotechnology has been amplified in different areas of science as well as agriculture in the present era. So, the present work was designed to evaluate the result of nitrate mediated silver nanoparticles (Nit-AgNPs) and indole acetic acid (IAA) on physio-biochemical features of the selected maize variety (Pahari white) under 40 and 80 mM salinity induction. Seeds were propagated in triplicates in earthen pots (18 cm inferior and superior inside diameter, 20 cm stature, and 2 cm breadth) filled with silt and soil (1:2) having 3.09–5.12 Electrical conductivity (EC), 6.8–7.3 pH, and 4–16% moisture contents. Scanning electron microscopy results showed the average particle size around 90 nm indicating a high surface area suitable for adsorption properties, agglomerated, roughly spherical, and were uniformly dispersed. Elemental quantification of biosynthesized AgNPs analyzed via energy dispersive X-ray spectroscopy showed a strong peak at 3.0 KeV along with the presence of elements K, N, O, and C. Results of Thermo-gravimetric Analysis (TGA)/Differential Thermal Analysis (DTA) showed endothermic major decline at 150–300°C, while exothermic peak at 300–400°C. The growth responses at 40 mM salinity concentration have been reduced representing from the least boundary of chlorophyll “a,” “b,” and peroxidase content, whereas; this adverse effect has been reduced by operation of Nit-AgNPs as separate treatment and in combination with IAA. From the current study, it has been concluded that salinity concentration at 80 mM adversely affected the values of osmolytes, protein, and superoxide dismutase whereas the maximum amplitude of proline reduced by the application of Nit-AgNPs as distinct treatment indicating that the plant behaves normal with the combined application of nanoparticles and IAA.     

Numerical investigation of turbulent flow generated in baffled stirred vessels equipped with three different turbines in one and two-stage system

The aim of this paper is to study the hydrodynamic behavior induced by a three different turbines: the FBT6 (six flat blades turbine), the RT6 (Rushton turbine), the PBT6 (pitched blades turbine). The turbulent flow generated in stirred tanks is numerically predicted by the resolution of the Navier-Stokes equation in conjunction with the RNG (Renormalization Group) of the k-ε turbulent model. These equations are solved by a control volume discretization method. The measurements were carried out for the one-stage and two-stage systems. The numerical results from the application of the CFD (computational fluid dynamics) code Fluent with the MRF (Multi Reference Frame) model are presented in the vertical and horizontal planes in the impeller stream region. The comparison between the numerical results and the experimental data showed a good agreement.     

Provisional reporting for rank joins

Rank join operators perform a relational join among two or more relations, assign numeric scores to the join results based on a given scoring function, and return K join results with the highest scores, while accessing a subset of data from the input relations. Most of the rank join operators compute a score upper bound for a join result that can be potentially obtained after retrieving the unseen data. A join result is kept in an output buffer, and is deterministically reported to the user if its score is greater than or equal to the score upper bound. The value of the score upper bound decreases subject to further data extraction from the relations. In case of Web services as data sources, which are characterized by non-negligible response time for every data fetch, the value of score upper bound might decrease slowly. Consequently, there is a long delay in reporting a join result stored in the output buffer. This paper addresses the problem of efficiently reporting a top join result obtained by joining the data of two Web services, which are characterized by non-negligible response time. We present a probabilistic reporting method which computes the confidence with which a join result may appear among final top-K joins. It reports a join result as soon as the measure of its confidence exceeds a given threshold. This helps in reporting a join result soon after its observation. An extensive experimental study with various settings of different operating parameters validates the importance of the proposed approach on both real and synthetic data sets. The results show that our proposed approach significantly reduces the average difference between the time when a join result is observed and the time when it is reported, while incurring negligible errors in the final results.     

Evaluation of Heat Treatment Effect on the Tensile Strength of Mild Steel Welded Joints Using Ultrasonic Testing

Russian Journal of Nondestructive Testing - The tensile strength of welded joints subjected to thermal stresses degrades with age. Tensile strength is generally assessed using tensile test, which...     

Magnetic Studies of Spin Wave in Fe/Ag Multilayer Films

Magnetic properties of Fe/Ag multilayer films are investigated and examined versus Fe layer thickness t _Fe. As a result, spontaneous magnetization M(T) temperature dependence has been revealed to be well described by a T ^3/2 law in all multilayer films (7 ?≤t _Fe≤60 ?). Spin-wave theory based on anisotropic ferromagnetic system has been also used to explain magnetization temperature dependence. For Fe layer thickness, approximate values for J ₀ bulk exchange interaction and J _s surface exchange interaction have been estimated. First principle calculations based on density functional theory (DFT) and Korringa–Kohn–Rostoker (KKR)—coherent potential approximation (CPA) method—combined with Local Spin Density Approximation (LSDA), are performed as well. Magnetic moment, in fcc Ag_1−x Fe _x and bcc Fe_1−x Ag _x systems, versus x is presented and discussed in terms of Fe content on magnetic coupling. Reasonable agreement between experimental data and theoretical calculations is highlighted.     

Explanation of Co Magnetic Moment Enhancement in (Co,Cu)-Doped ZnO by First-Principle Calculations

By ab-initio calculations on Zn_0.95?x Co_0.05Cu _x O, we study the variations of magnetic moments versus Cu concentration. The electronic structure is calculated by using the Korringa?CKohn?CRostoker (KKR) method combined with coherent potential approximation (CPA). We show that the total magnetic moment and magnetic moment of Co increase with increasing Cu content. From a density of state (DOS) analysis, we propose an explanation of the enhancement of the Co magnetic moment versus Cu concentration.     

Boronic acid-modified magnetic materials for antibody purification

Aminophenyl boronic acids can form reversible covalent ester interactions with cis-diol-containing molecules, serving as a selective tool for binding glycoproteins as antibody molecules that possess oligosaccharides in both the Fv and Fc regions. In this study, amino phenyl boronic acid (APBA) magnetic particles (MPs) were applied for the magnetic separation of antibody molecules. Iron oxide MPs were firstly coated with dextran to avoid non-specific binding and then with 3-glycidyloxypropyl trimethoxysilane to allow further covalent coupling of APBA (APBA_MP). When contacted with pure protein solutions of human IgG (hIgG) and bovine serum albumin (BSA), APBA_MP bound 170 ± 10 mg hIgG g⁻¹ MP and eluted 160 ± 5 mg hIgG g⁻¹ MP, while binding only 15 ± 5 mg BSA g⁻¹ MP. The affinity constant for the interaction between hIgG and APBA_MP was estimated as 4.9 × 10⁵ M⁻¹ (K_a) with a theoretical maximum capacity of 492 mg hIgG adsorbed g⁻¹ MP (Q_max), whereas control particles bound a negligible amount of hIgG and presented an estimated theoretical maximum capacity of 3.1 mg hIgG adsorbed g⁻¹ MP (Q_max). APBA_MPs were also tested for antibody purification directly from CHO cell supernatants. The particles were able to bind 98% of IgG loaded and to recover 95% of pure IgG (purity greater than 98%) at extremely mild conditions.     

Composition of peel essential oils from four selected Tunisian Citrus species: Evidence for the genotypic influence

The peel essential oils from four selected Tunisian Citrus species: sweet orange (Citrus sinensis Osbeck), mandarin (Citrus reticulata Blanco); sour orange (Citrus aurantium L.) and pummelo (Citrus grandis Osbeck), cultivated under the same pedoclimatic and cultural conditions have been analysed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The essential oils content ranged from 1.06% to 4.62% (w/w) in pummelo and mandarin, respectively. The qualitative and quantitative analysis led to the identification of 70 components in all oil samples. The analysed oils consist mainly in monoterpene hydrocarbons (97.59–99.3%), with limonene (92.52–97.3%) and β-pinene (1.37–1.82) being the major constituents. The remaining chemical classes were weakly represented (<1%). Both qualitative and quantitative differences between oil samples have been observed and numerous components have been proposed as marker compounds. Since the influence of different environmental factors has been eliminated, the observed chemical variability between the studied species and cultivars seems likely to results from the genetic variability.     

Determination of Gasketed and Non-gasketed Flanged Pipe Joint’s Capacity Subjected to Combined Loading: An Experimental Approach

This paper presents details of an experimental set up for the determination of a flanged pipe joint’s capacity subjected to singly and combined loading. Most international codes and design standards have rules based on internal pressure loading only and a little or no consideration is given to the loads acting in combination. The main aim of this experimental setup is the performance testing of both gasketed and non-gasketed flange pipe joints subjected to singly and combined loading i.e. internal pressure plus axial plus bending in different combinations. A test rig is designed and manufactured and details of design, strain gauging, instrumentation, calibration and assembly of different parts used in test rig are presented and discussed. Results for strains on bolts and test rig under application of combined loading observed are also presented.