DSBS: A Novel Dependable Secure Broadcast Stream over Lossy Channels

Confidential authenticated broadcast/multi cast over lossy channels is an important and challenging problem. Applications include the continuous confidential authentication of radio and TV internet broadcast/multicast data distribution by satellite and critical data broadcast in critical tasks (e.g. sensor network for military tasks). Main challenges are authenticity, confidentiality, loss-tolerance, efficiency. Asymmetric cryptography approaches have high security but are expensive in computation and communication. In this paper we propose and prototype a novel loss-tolerance mechanism for lossy channels ensuring authenticity, confidentiality, DoS resistance, efficiency and simplicity. Most applications in practice do not need ideal and perfect real-time task and a minor delay around some seconds is completely acceptable, except a few applications such as safety beacons in VANET. In many applications, such as updating code memory of MANET, delay around some minutes is acceptable, too. Hence, our aim is to provide a robust and dependable loss-tolerant secure broadcast stream at cost of delayed-verification. As an experimental implementation we prototype our proposal in a wireless sensor networks to show its efficiency.     

Adaptive simulation of wave propagation problems including dislocation sources and random media

An adaptive Tikhonov regularization is integrated with an h-adaptive grid-based scheme for simulation of elastodynamic problems, involving seismic sources with discontinuous solutions and random media. The Tikhonov method is adapted by a newly-proposed detector based on the MINMOD limiters and the grids are adapted by the multiresolution analysis (MRA) via interpolation wavelets. Hence, both small and large magnitude physical waves are preserved by the adaptive estimations on non-uniform grids. Due to developing of non-dissipative spurious oscillations, numerical stability is guaranteed by the Tikhonov regularization acting as a post-processor on irregular grids. To preserve waves of small magnitudes, an adaptive regularization is utilized: using of smaller amount of smoothing for small magnitude waves. This adaptive smoothing guarantees also solution stability without over smoothing phenomenon in stochastic media. Proper distinguishing between noise and small physical waves are challenging due to existence of spurious oscillations in numerical simulations. This identification is performed in this study by the MINMOD limiter based algorithm. Finally, efficiency of the proposed concept is verified by: 1) three benchmarks of one-dimensional (1-D) wave propagation problems; 2) P-SV point sources and rupturing line-source including a bounded fault zone with stochastic material properties.     

A V(L) single-domain antibody library shows a high-propensity to yield non-aggregating binders

A synthetic human V(L) phage display library, created by the randomization of all complementarity-determining regions (CDRs) in a V(L) scaffold, was panned against three test antigens to determine the propensity of the library to yield non-aggregating binders. A total of 22 binders were isolated against the test antigens and the majority (20) were monomeric. Thus, human V(L) repertoires provide an efficient source of non-aggregating binders and represent an attractive alternative to human V(H) repertoires, which are notorious for containing high proportions of aggregating species. Moreover, the solubility of V(L)s, in contrast to V(H)s, appears much less CDR dependent.     

Cu(acac)<Subscript>2</Subscript>–PVA composite nanofibers in catalysis of Michael addition of carbon nucleophiles to α,β-unsaturated carbonyl compounds

Copper (II) acetylacetonate containing nanofibers of polyvinyl alcohol (Cu(acac)₂–PVA) were prepared by electrospinning and characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, inductively coupled plasma (ICP) and diffuse reflectance spectroscopy. The obtained nanofibers were almost uniform and uniaxially aligned with their longitudinal axes oriented randomly and no entanglement was observed between them. It was also found that Cu(acac)₂ was embedded as distinct nanoparticles inside and over the walls of the nanofibers. The obtained nanocomposite was successfully used as a recoverable heterogeneous catalyst in the Michael addition reaction of carbon nucleophiles such as malononitrile, indole and 2-methylindole to various α,β-unsaturated carbonyl compounds. The Michael addition reaction proceeded smoothly at room temperature in dry THF. Under very mild reaction conditions, good to excellent yields of the desired products were obtained. Although one favorable feature of the catalyst was ease of recycling, a minor decrease in its efficiency during successive runs was observed. It was found that 7% decrease in efficiency after four successive runs may be due to the slight leaching of Cu(acac)₂ into the solution based on an ICP analysis of the recovered catalyst of the fourth run.     

Trans‐free fats through interesterification of canola oil/palm olein or fully hydrogenated soybean oil blends

Binary blends of canola oil (CO) and palm olein (POo) or fully hydrogenated soybean oil (FHSBO) were interesterified using commercial lipase, Lypozyme TL IM, or sodium methoxide. Free fatty acids (FFA) and soap content increased and peroxide value (PV) decreased after enzymatic or chemical interesterification. No difference was observed between the PV of enzymatically and chemically interesterified blends. Enzymatically interesterified fats contained higher FFA and lower soap content than chemically prepared fats. Slip melting point (SMP) and solid‐fat content (SFC) of CO and POo blends increased, whereas those of CO and FHSBO blends decreased after chemical or enzymatic interesterification. Enzymatically interesterified CO and POo blends had lower SMP and SFC (at some temperatures) than chemically interesterified blends. The status was reverse when comparing chemically and enzymatically interesterified CO and FHSBO blends. The induction period for oxidation at 120°C of blends decreased after interesterification. However, chemically interesterified blends were more oxidatively stable than enzymatically interesterified blends. Interesterified blends of CO and POo or FHSBO displayed characteristics suited to application as trans‐free soft tub, stick, roll‐in and baker's margarine, cake shortening and vanaspati fat.     

Thermal and biodegradation properties of poly(lactic acid)/rice straw composites: effects of modified pulping products

Iranian Polymer Journal - In this work, rice straw (RS) as an abundant biomass was chemically thermoplasticized through alkali pulping and benzylation reactions, which destroy inter- and...     

Digital Image Processing Technique to Investigate the Hydrodynamics of an Airlift Reactor with Double Downcomer

Digital image processing, an innovative cost‐effective technique, was employed to investigate the hydrodynamics of a rectangular internal loop airlift reactor with double downcomer. The whole reactor was divided into two downcomers and a riser by means of two vertical blades to achieve a new geometry. Air and water served as gas and liquid media. Experimental measurements were performed by visualizing the concentration of a colored tracer by a digital camera. The captured successive images at specified time intervals were analyzed by the ImageJ software to turn images into quantifiable data. For four reactor geometries, the residence time distribution curves in individual sections and the liquid mixing performance were determined by this noninvasive method. The speed of this technique to capture real‐time data of flow patterns may be one of the most important concerns for imaging multiphase flows in process industries.     

A kinetic study on the electrophoretic deposition of hydroxyapatite–titania nanocomposite based on a statistical approach

In the present study, the electrophoretic deposition (EPD) process of hydroxyapatite–titania nanocomposite was kinetically described by the use of response surface methodology (RSM). The electrostatic interaction between particles in ethanol based suspensions was determined by Zeta potential and particle size analyses. After successful electrophoretic deposition from hydroxyapatite–titania suspensions with 0, 10 and 20 wt% of titania nanoparticles, it was shown that Baldisserri model can well reproduce the experimental data among the other semi-empirical kinetic equations. The as-deposited hydroxyapatite–titania nanocomposites were characterized employing SEM, AFM, XRD, and FT-IR analyses. Then, the effects of deposition voltage, deposition time and wt% TiO₂ on the kinetic of EPD at two time intervals (10–60 s and 60–300 s) were identified and quantified via RSM based on a central composite design (CCD). According to the results obtained from the statistical analysis, it was found that the deposition rate decreases by an increase in wt% TiO₂ and time. Also, a transition in deposition mechanism from linear to parabolic mode was observed and two second order polynomial equations were fitted to the response (deposit weight) at each time intervals.     

Chlorophyllase-Catalyzed Chlorophyll Removal from Vegetable Oils Using Recombinant Eukaryotic and Prokaryotic Enzymes

Chlorophyllase converts chlorophyll and pheophytin into their colorless derivatives (chlorophyllide/pheophorbide and phytol). This activity can be used in chlorophyll removal from vegetable oils. Chlorophyllase genes from Oscillatoria acuminata (OscChlase) and Citrus aurantium (CitChlase) were isolated, cloned, and expressed in E. coli. Bioinformatics analysis showed that both chlorophyllases shared a conserved GHSXG lipase motif responsible for their catalytic activity. SDS-PAGE and immunoblot assays revealed that both enzymes had a molecular weight of 35 kDa. The purified chlorophyllases were stable at a broad range of temperatures and showed the highest activity at 40 °C. OscChlase and CitChlase exhibited the highest activity at pH 6.0 and 7.0, respectively. Enzyme kinetics analysis revealed that OscChlase was able to hydrolyze bacteriochlorophyll-a more efficiently than the recombinant CitChlase (Vmax/Km of 0.38 for OscChlase vs. 0.01 min⁻¹ mg protein for CitChlase). Instead, CitChlase hydrolyzed chlorophyll-b more efficiently than OscChlase. Both enzymes were able to reduce the chlorophyll content of olive (from 623.1 to as low as 87.2 mg per kg oil) and canola oil (from 537.2 to as low as 101.1 mg per kg oil). The ratio of oil to the aqueous reaction media affected chlorophyll hydrolysis (P < 0.05). The lower the oil ratio was (10%), the higher the chlorophyll removal was (75–86%). The efficiency of CitChlase in chlorophyll removal was higher than that of OscChlase at oil ratios of 10 and 20, but lower at 30% ratio (P < 0.05). This is the first report on the application of recombinant OscChlase and CitChlase in chlorophyll removal (up to 86%) from vegetable oils.     

Is there an association between intradialytic hypotension and serum magnesium changes?

Intradialytic hypotension (IDH) is the most common complication of hemodialysis (HD). The aim of this study was to investigate the significance of intradialytic changes of serum magnesium (sMg) and its relation to IDH. We considered 58 patients undergoing HD. Serum magnesium was measured at start, after 2 hours, and at the end of the HD sessions. Total sMg concentration corrected for albumin was according to Krolles proposed formula. Blood pressure was measured every 30 min. Data were analyzed by SPSS.15. A P value of less than 0.05 was considered as significant. Occurrence of IDH among HD patients was 27.6% (16/58). Serum magnesium decreased significantly during HD session (P<0.05). Comparing corrected sMg in IDH group with non-IDH group showed that: corrected sMg was 0.66 ± 0.14 mmol/L vs. 0.84 ± 0.26 mmol/L at the start of dialysis (P=0.43), 0.62 ± 0.17 mmol/L vs. 0.74 ± 0.23 mmol/L (P=0.04) at 2 hours, and 0.61 ± 0.12 mmol/L vs. 0.72 ± 0.22 mmol/L (P=0.03) at the end of dialysis. Intradialytic hypotension episodes were significantly related to a decrease in sMg during dialysis (P=0.02). There was a significant decrease in sMg levels during dialysis. Intradialytic hypotension was significantly related to lowered sMg levels during dialysis.