6-Benzylaminopurine Alleviates the Impact of Cu2+ Toxicity on Photosynthetic Performance of Ricinus communis L. Seedlings

Copper (Cu) is an essential element involved in various metabolic processes in plants, but at concentrations above the threshold level, it becomes a potential stress factor. The effects of two different cytokinins, kinetin (KIN) and 6-benzylaminopurine (BAP), on chlorophyll a fluorescence parameters, stomatal responses and antioxidation mechanisms in castor (Ricinus communis L.) under Cu²⁺ toxicity was investigated. Ricinus communis plants were exposed to 80 and 160 μM CuSO₄ added to the growth medium. Foliar spraying of 15 μM KIN and BAP was carried out on these seedlings. The application of these cytokinins enhanced the tissue water status, chlorophyll contents, stomatal opening and photosynthetic efficiency in the castor plants subjected to Cu²⁺ stress. The fluorescence parameters, such as Fm, Fv/Fo, Sm, photochemical and non-photochemical quantum yields, energy absorbed, energy trapped and electron transport per cross-sections, were more efficiently modulated by BAP application than KIN under Cu²⁺ toxicity. There was also effective alleviation of reactive oxygen species by enzymatic and non-enzymatic antioxidation systems, reducing the membrane lipid peroxidation, which brought about a relative enhancement in the membrane stability index. Of the various treatments, 80 µM CuSO₄ + BAP recorded the highest increase in photosynthetic efficiency compared to other cytokinin treatments. Therefore, it can be concluded that BAP could effectively alleviate the detrimental effects of Cu²⁺toxicity in cotyledonary leaves of R. communis by effectively modulating stomatal responses and antioxidation mechanisms, thereby enhancing the photosynthetic apparatus’ functioning.     

Is Photoprotection of PSII One of the Key Mechanisms for Drought Tolerance in Maize?

Drought is one of the most important abiotic stress factors limiting maize production worldwide. The objective of this study was to investigate whether photoprotection of PSII was associated with the degree of drought tolerance and yield in three maize hybrids (30Y87, 31R88, P3939). To do this, three maize hybrids were subjected to three cycles of drought, and we measured the activities of photosystem II (PSII) and photosystem I (PSI). In a second field experiment, three maize hybrids were subjected to drought by withholding irrigation, and plant water status, yield and yield attributes were measured. Drought stress decreased leaf water potential (Ψ_L) in three maize hybrids, and this reduction was more pronounced in hybrid P3939 (−40%) compared to that of 30Y87 (−30%). Yield and yield attributes of three maize hybrids were adversely affected by drought. The number of kernels and 100-kernel weight was the highest in maize hybrid 30Y87 (−56%, −6%), whereas these were lowest in hybrid P3939 (−88%, −23%). Drought stress reduced the quantum yield of PSII [Y(II)], photochemical quenching (qP), electron transport rate through PSII [ETR(II)] and NPQ, except in P3939. Among the components of NPQ, drought increased the Y(NPQ) with concomitant decrease in Y(NO) only in P3939, whereas Y(NO) increased in drought-stressed plants of hybrid 30Y87 and 31R88. However, an increase in cyclic electron flow (CEF) around PSI and Y(NPQ) in P3939 might have protected the photosynthetic machinery but it did not translate in yield. However, drought-stressed plants of 30Y87 might have sufficiently downregulated PSII to match the energy consumption in downstream biochemical processes. Thus, changes in PSII and PSI activity and development of NPQ through CEF are physiological mechanisms to protect the photosynthetic apparatus, but an appropriate balance between these physiological processes is required, without which plant productivity may decline.     

Bayesian methods for time‐varying state and parameter estimation in induction machines

This paper addresses the problem of nonlinear time‐varying state and parameter estimation of induction machines (IMs) on the basis of a third‐order electrical model. The objectives of this paper are threefold. The first objective is to propose the use of an improved particle filter (IPF) with better proposal distribution for nonlinear and non‐Gaussian state and parameter estimation. The second objective is to extend the state and parameter estimation techniques (i.e., extended Kalman filter (EKF), unscented Kalman filter (UKF), particle filter (PF), and IPF) to better handle nonlinear and non‐Gaussian processes without a priori state information, by utilizing a time‐varying assumption of statistical parameters. In this case, the state vector to be estimated at any instant is assumed to follow a Gaussian model, where the expectation and the covariance matrix are both random. The third objective is to compare the performances of EKF, UKF, PF, and IPF in estimating the states of the power process model representing the IM (i.e, the rotor speed, the rotor flux, the stator flux, the rotor resistance, and the magnetizing inductance) and their abilities to estimate some of the key system parameters, which are needed to define the IM process model. The results show that the IPF provides a significant improvement over the PF because, unlike the PF, which depends on the choice of sampling distribution used to estimate the posterior distribution, the IPF yields an optimum choice of the sampling distribution, which also accounts for the observed data. This conclusion is also supported by the experimental results. Copyright © 2014 John Wiley & Sons, Ltd.     

A survey on indexing techniques for mobility in Internet of Things': Challenges,performances, and perspectives

Mobile nodes arouse new challenges that expand the performance in those environments. The nodes of Internet of Things (IoT) generate a large amount of data, which have to be stored and processed in a seamless and interpretable form by indexing. Therefore, indexing is a challenge in IoT, particularly when the nodes are mobile. The current indexing techniques dedicated to mobile environments are unsatisfying because the data are transmitted from different locations within different time periods and randomness of sensor movement. Although huge research efforts have been dedicated to this subject amid the last decades, little consideration has been paid for the research summarization and guidance. The objective of this survey is to identify the relationship between activities of mobile sensors in the context of IoT, that concerned on transferring and collecting data as well as the effectiveness of indexing techniques. The contribution of this review is to investigate the techniques of mobile IoT nodes, to find the source of challenges that adversely affect the index effectiveness. In‐depth investigation and analyses of approaches to apply IoT mobile nodes will enable the researcher to understand the behavior of mobile environments to extract the deformities that adversely affect the indexing effectiveness. The analyzed approaches are meta‐heuristic, spatial‐temporal indexing, and prediction model approach. Each approach is analyzed by discussing the features and limitations from the mobility perspectives. Furthermore, the indexing techniques are analyzed according to their features and limitations and mobile IoT indexing requirements. In conclusion, recognize and contemplate different open issues that got little focus or still unknown at this point.     

A new strategy for generating shortest addition sequences

An addition sequence problem is given a set of numbers X = {n ₁, n ₂, . . . , n _m }, what is the minimal number of additions needed to compute all m numbers starting from 1? This problem is NP-complete. In this paper, we present a branch and bound algorithm to generate an addition sequence with a minimal number of elements for a set X by using a new strategy. Then we improve the generation by generalizing some results on addition chains (m = 1) to addition sequences and finding what we will call a presumed upper bound for each n _j , 1 ≤ j ≤ m, in the search tree.     

Harvesting relational tables from lists on the web

A large number of web pages contain data structured in the form of ??lists??. Many such lists can be further split into multi-column tables, which can then be used in more semantically meaningful tasks. However, harvesting relational tables from such lists can be a challenging task. The lists are manually generated and hence need not have well-defined templates??they have inconsistent delimiters (if any) and often have missing information. We propose a novel technique for extracting tables from lists. The technique is domain independent and operates in a fully unsupervised manner. We first use multiple sources of information to split individual lines into multiple fields and then, compare the splits across multiple lines to identify and fix incorrect splits and bad alignments. In particular, we exploit a corpus of HTML tables, also extracted from the web, to identify likely fields and good alignments. For each extracted table, we compute an extraction score that reflects our confidence in the table??s quality. We conducted an extensive experimental study using both real web lists and lists derived from tables on the web. The experiments demonstrate the ability of our technique to extract tables with high accuracy. In addition, we applied our technique on a large sample of about 100,000 lists crawled from the web. The analysis of the extracted tables has led us to believe that there are likely to be tens of millions of useful and query-able relational tables extractable from lists on the web.     

Watermark location via back-lighting modelling and verso registration

We consider the location of paper watermarks in documents that present problems such as variable paper thickness, stain and other damage. Earlier work has shown success in exploiting a computational model of backlit image acquisition – here we enhance this approach by incorporating knowledge of surface verso features. Robustly removing recto features using established techniques, we present a registration approach that permits similarly robust removal of verso, leaving only features attributable to watermark, folds, chain lines and inconsistencies of paper manufacture. Experimental results illustrate the success of the approach.     

pH‐sensitive hydrogels based on bovine serum albumin for anticancer drug delivery

Protein conjugates consisting of hydroxyethyl methacrylate and acrylic acid monomers in the presence of bovine serum albumin (BSA) were prepared by gamma irradiation to examine the potential use of these hydrogels in the controlled drug release systems. The study parameter was the BSA content in the as‐prepared conjugates. Polymers were characterized with FTIR, scanning electron microscopy (SEM), and swelling studies. The polymerization reaction caused the rearrangement of the BSA carbonyl hydrogen bonding and finally led to the modification of the BSA secondary structure as proved by FTIR. SEM proved that the prepared conjugates matrices are porous, with a three‐dimensional interconnected microstructure. The swelling kinetics of the hydrogels and the release dynamics of an anticancer model drug (flutamide) have been studied. High equilibrium swelling values, up to 1550%, could be observed and were correlated with the increase in pH, temperature, and BSA content. The mechanism of swelling changed from Fickian to non‐Fickian by reducing the acidity of the medium. This study proved that there is a direct relationship between the protein content in the conjugates and both the loaded and the released drug. These pH responsive conjugates may be exploited for the delivery of flutamide. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Potentiometric Determination of Alkyl Dimethyl Hydroxyethyl Ammonium Surfactant by a New Chemically Modified Carbon Past Electrode

This paper introduces the development a new chemically modified carbon paste electrode (CMCPE) for the determination of a cationic surfactant. The paste is based on alkyl dimethyl hydroxyethyl ammonium chloride (ADHACl) with phosphomolybdic acid as an ion‐exchanger (ADHA‐PM). The electrode exhibits a Nernstian slope of 59.1 ± 0.5 mV/decade for ADHA ions in the concentration range 1.0 × 10^?6–1.0 × 10^?3 M with the limit of detection of 8.2 × 10^?7 M. The proposed electrode has a fast and stable response time of 5–8 s, a good reproducibility and it can be used in the pH range of 2.2–9.0. Selectivity coefficients, determined by a matched potential method and separate solution method, showed high selectivity for ADHA over a large number of inorganic cations and organic cations. These characteristics of the electrode enable it to be used successfully for determination of ADHA in shampoo and liquid detergents solutions by standard addition and the calibration curve methods. In addition, the modified electrode was applied as an indicator electrode in potentiometric titration and successfully used to determine ADHA in water samples with satisfactory results.