AgNPs doped TEOS sol–gel coatings to prevent the adhesion of marine fouling organisms

Biosynthesis of silver nanoparticles (AgNPs) using plants is considered to be cost effective and more eco‐friendly than conventional techniques. In the authors’ previous study, they reported the biosynthesis of AgNPs using fruit extract of Aegle marmelos which were of spherical shape and high crystallinity. In order to achieve enhanced synthesis, optimisation of process parameters influencing the yield of AgNPs has been carried out in this study. Box–Behnken design has been employed to optimise the parameters in order to enhance the synthesis of AgNPs. The antimicrofouling activity of the optimised AgNPs was determined by preparing AgNPs doped TEOS sol–gels (SNSGs) and evaluating their antibiofilm activity. In addition to this, antimacrofouling activity of the AgNPs was studied against molluscs viz. Patella sp. and Trochus sp. as model organisms. Anticrustacean assay was also performed with the larvae of brine shrimp (Artemia salina) as a model crustacean fouling organism. The results indicated that the AgNPs could completely inhibit the attachment of molluscs and significantly increased the percentage of mortality against crustacean fouling larvae. Thus, this study gives scope for the possible development of formulations containing AgNPs as effective antifouling agents that could prevent the adhesion of micro and macrofoulers thereby preventing marine biofouling.Inspec keywords: silver, nanoparticles, adhesion, nanobiotechnology, microorganisms, nanofabrication, sol‐gel processing, liquid phase deposited coatings, thin films, organic compoundsOther keywords: biosynthesis, silver nanoparticle doped TEOS sol‐gel coatings, adhesion, marine fouling organisms, Box‐Behnken design, process parameter optimisation, antimicrofouling activity, antibiofilm activity, antimacrofouling activity, molluscs, Patella sp, Trochus sp, model organisms, anticrustacean assay, brine shrimp larvae, Artemia salina, model crustacean fouling organism, crustacean fouling larvae, antifouling agents, Ag     

Ternary nanocomposite designed by MWCNT backbone PPy/Pd for efficient catalytic approach toward reduction and oxidation reactions

An induced active palladium nanoparticle (Pd NP) on multiwall carbon nanotube with polypyrrole matrix (MWCNT/PPy/Pd) was prepared and their physiochemical properties were investigated. The XPS (X-ray photoelectron spectroscopy) analysis showed the important amine and imine linkage at 400.3?eV and 398.8?eV for the interaction of the polymer matrix. FTIR spectroscopy proved the polypyrrole stretching frequencies and palladium nitrogen interaction (Pd-N at 1618?cm^?1). TGA-DSC analysis showed that 51% of polymer composite remained up to 1000?°C. The developed nanocomposite (NC) catalytic ability was tested in p-nitrophenol reduction and methanol oxidation studies. The kinetic rate constant (k) was 0.193?min^?1 and NC exhibited good reusability up to 10 cycles for p-nitrophenol reduction. The electrochemical measurements indicate that MWCNT/PPy/Pd has a significantly high active surface area (3.13?cm^?2), low onset potential and high current density. MWCNT/PPy/Pd ternary NC is a capable candidate for both electro-oxidation of methanol and a reduction of 4-nitrophenol.     

<Emphasis Type="Italic">k–µ</Emphasis> fading channels: a finite state Markov modelling approach

Finite state Markov channel (FSMC) is the automatic choice for accurate modelling of slow fading channels with memory. FSMC model for a k–µ fading channel is investigated in this paper. Small-scale variations of the fading signal under Line-Of-Sight conditions are represented by k–µ fading distributions. Here, FSMC is constructed by partitioning the fading amplitude into several regions. Each region corresponds to a particular state in the Markov model. The transition among these channel states characterizes the physical fading process. Performance measures such as steady-state probability, state-transition probability, level crossing rate and state-time duration corresponding to the k–µ fading channel are derived, plotted and analysed. Finally, numerical results prove that FSMC modelling provides an effective way to reflect the nature of the k–µ fading channel.     

Isolation and Profiling of Circulating Tumor‐Associated Exosomes Using Extracellular Vesicular Lipid–Protein Binding Affinity Based Microfluidic Device

Extracellular vesicles (EVs) are emerging as a potential diagnostic test for cancer. Owing to the recent advances in microfluidics, on‐chip EV isolation is showing promise with respect to improved recovery rates, smaller necessary sample volumes, and shorter processing times than ultracentrifugation. Immunoaffinity‐based microfluidic EV isolation using anti‐CD63 is widely used; however, anti‐CD63 is not specific to cancer‐EVs, and some cancers secrete EVs with low expression of CD63. Alternatively, phosphatidylserine (PS), usually expressed in the inner leaflet of the lipid bilayer of the cells, is shown to be expressed on the outer surface of cancer‐associated EVs. A new exosome isolation microfluidic device (^newExoChip), conjugated with a PS‐specific protein, to isolate cancer‐associated exosomes from plasma, is presented. The device achieves 90% capture efficiency for cancer cell exosomes compared to 38% for healthy exosomes and isolates 35% more A549‐derived exosomes than an anti‐CD63‐conjugated device. Immobilized exosomes are then easily released using Ca²⁺ chelation. The recovered exosomes from clinical samples are characterized by electron microscopy and western‐blot analysis, revealing exosomal shapes and exosomal protein expressions. The ^newExoChip facilitates the isolation of a specific subset of exosomes, allowing the exploration of the undiscovered roles of exosomes in cancer progression and metastasis.     

Metaheuristic Secure Clustering Scheme for Energy Harvesting Wireless Sensor Networks

Recently, energy harvesting wireless sensor networks (EHWSN) have increased significant attention among research communities. By harvesting energy from the neighboring environment, the sensors in EHWSN resolve the energy constraint problem and offers lengthened network lifetime. Clustering is one of the proficient ways for accomplishing even improved lifetime in EHWSN. The clustering process intends to appropriately elect the cluster heads (CHs) and construct clusters. Though several models are available in the literature, it is still needed to accomplish energy efficiency and security in EHWSN. In this view, this study develops a novel Chaotic Rider Optimization Based Clustering Protocol for Secure Energy Harvesting Wireless Sensor Networks (CROC-SEHWSN) model. The presented CROC-SEHWSN model aims to accomplish energy efficiency by clustering the node in EHWSN. The CROC-SEHWSN model is based on the integration of chaotic concepts with traditional rider optimization (RO) algorithm. Besides, the CROC-SEHWSN model derives a fitness function (FF) involving seven distinct parameters connected to WSN. To accomplish security, trust factor and link quality metrics are considered in the FF. The design of RO algorithm for secure clustering process shows the novelty of the work. In order to demonstrate the enhanced performance of the CROC-SEHWSN approach, a wide range of simulations are carried out and the outcomes are inspected in distinct aspects. The experimental outcome demonstrated the superior performance of the CROC-SEHWSN technique on the recent approaches with maximum network lifetime of 387.40 and 393.30 s under two scenarios.     

Magnetic susceptibility and specific heat of Pr2?xCexCuO4?y

We report here the measurements of magnetic susceptibility of Pr_2–xCe_xCuO_4–y (x=0, 0.05 and 0.15) from 2K to 300K and the specific heat of Pr_1.85Ce_0.15CuO₄ between 6K and 60K. Fitting of the magnetic susceptibility data to a Curie-Weiss law gave effective magnetic moment (p_eff) values close to the free ion value of 3.58_B for Pr³⁺. p_eff was found to decrease with increase in cerium concentration. The site symmetry of Pr³⁺ in Pr_2–xCe_xCuO_4–y (PCCO) host is D_4h and a crystal field (CF) Hamiltonian appropriate to tetragonal symmetry was used to analyze the magnetic susceptibility data. J-mixing of all the thirteen multiplets of Pr³⁺ and intermediate coupled wave functions have been included. A best set of CF parameters obtained not only explains the magnetic susceptibility but also the inelastic neutron scattering spectra (INS) reasonably well. The Schottky component together with Debye and Einstein contributions successfully accounts for the measured specific heat.     

Using aerial imagery and digital photography to monitor growth and yield in winter wheat

Monitoring wheat (Triticum aestivum L.) performance throughout the growing season provides information on productivity and yield potential. Remote sensing tools have provided easy and quick measurements without destructive sampling. The objective of this study was to evaluate genetic variability in growth and performance of 20 wheat genotypes under two water regimes (rainfed and irrigated), using spectral vegetation indices (SVI) estimated from aerial imagery and percentage ground cover (%GC) estimated from digital photos. Field experiments were conducted at Bushland, Texas in two growing seasons (2014–2015 and 2015–2016). Digital photographs were taken using a digital camera in each plot, while a manned aircraft collected images of the entire field using a 12-band multiple camera array Tetracam system at three growth stages (tillering, jointing and heading). Results showed that a significant variation exists in SVI, %GC, aboveground biomass and yield among the wheat genotypes mostly at tillering and jointing. Significant relationships for %GC from digital photo at jointing was recorded with Normalized Difference Vegetation Index (NDVI) at tillering (coefficient of determination, R² = 0.84, p< 0.0001) and with %GC estimated from Perpendicular Vegetation Index (PVI) at tillering (R² = 0.83, p< 0.0001). Among the indices, Ratio Vegetation Index (RVI), Green-Red VI, Green Leaf Index (GLI), Generalized DVI (squared), DVI, Enhanced VI, Enhanced NDVI, and NDVI explained 37–99% of the variability in aboveground biomass and yield. Results indicate that these indices could be used as an indirect selection tool for screening a large number of early-generation and advanced wheat lines.     

商业化开放原始码软件：这是一种“矛盾修饰法”吗？

根据字典的说明．所谓的“矛盾修饰法”是指“言词中包含一组位置相近的矛盾字词（通常是存在同一句子中）．或是矛盾或不协调字词的组合。”     

Effects on spermatogenesis in swiss mice of a protein isolated from the roots of Ricinus communis (Linn.) (Euphorbiaceae)

This study was aimed to evaluate the effect on spermatogenesis of a 62 kDa protein (Rp) isolated from 50% ethanolic extract of the root of Ricinus communis in mice. A dose response study in mice revealed that 25mg/kg body weight/day was the most effective dose. Swiss strain mature male mice of 30 days old were divided into two group namely control and Rp treated (25mg/kg body weight/day). The study showed that sperm motility and count were decreased significantly in the treated group as compared to the control. The fertility index of the treated groups was reduced by 100%. The activity of HMG Co A reductase and cholesterol were increased significantly in the treated group. The testicular activities of 3βHSD, 17βHSD, glucose 6-phosphate dehydrogenase and malic enzyme and the level of serum testosterone were decreased significantly in the treated group. The expression of 3βHSD and 17βHSD were decreased and the expression of StAR increased significantly in the treated group as compared to the control. Proteolytic digestion of the native protein with trypsin and chymotrypsin showed that the proteolytic cleavage did not affect the spermicidal action of Rp. Hence this study can be concluded that Rp impaired spermatogenesis in vivo by suppressing the production of testosterone.     

Linux20岁了!企鹅准备好要飞了吗?

今年度的”LinuxCon North America 2011”研讨会已于8月1 9号在加拿大的温哥华顺利落幕[注],会中也同步欢庆Linux问世20周年纪念.温哥华这座城市通常都是以灰蒙蒙又阴湿多雨的天气闻名,但是Linux 之神(如果有的话)一定是特别为了此番意义非凡的Linux 20周年纪念活动出手护持,因为这次研讨会举行期间的天气竟然出奇地晴朗!由于今年刚好也是WindRiver创建30周年的重要纪念年度,不禁让我联想到,这一切是否预示了某些重大事件即将到来.