Study of hydrogen production by three strains of Chlorella isolated from the soil in the Algerian Sahara

In this study, the photosynthetic hydrogen production rates by some strains of green microalgae were investigated. Three strains of Chlorella isolated from arid soil and foggaras's water in the Algerian Sahara were used. Chlorella sorokiniana strain Ce, Chlorella salina strain Mt and Chlorella sp strain Pt6 produced hydrogen gas under sulphur-deprived conditions, but its rate was dependent on strain type and oxygen partial pressure in medium. In C. sorokiniana strain Ce, the maximum value of hydrogen accumulated was 147 ml at 222 h at 2% of O₂ pressure. Compared to C. sorokiniana strain Ce, C. salina strain Mt and Chlorella sp strain Pt6 produced less amount of hydrogen, but they were able to sustain with an O₂ partial pressure of up to 11–15.4%. Our data were compared with hydrogen production by Chlamydomonas reinhardtii. In this communication, the relationship between physiological behaviour, biochemical characteristic (starch and protein) and rates gas production (O₂ and H₂) was also specified.     

A recursive hierarchical parametric estimation algorithm for nonlinear systems described by Wiener‐Hammerstein models

In this paper, a recursive hierarchical parametric estimation (RHPE) algorithm is proposed for stochastic nonlinear systems which can be described by Wiener‐Hammerstein (W‐H) mathematical models. The formulation of parameters estimation problem is based on the prediction error approach and the gradient techniques. The convergence analysis of the developed RHPE algorithm is derived using stochastic gradient‐based theory. Wiener‐Hammerstein hydraulic process is treated to prove the efficiency of the proposed approach.     

Nutritional characteristics,biochemical composition and antioxidant activities of Moroccan Oat varieties

Oat has been recognized as a healthy food for a long time. In this study, physicochemical analysis including, moisture, pH, ash, fibres, proteins, starch, carbohydrates, some minerals, sugars, fatty acids, sterols, total phenolic, and flavonoid contents of four Moroccan Oat varieties (Amlal, Tissir, Zahri and Ghali) were investigated. Additionally, starch morphology has been described according to scanning electron microscopy, and viscosity as measured on a rotary rheometer, increased with stabilization time. Furthermore, Oat extracts were analyzed with regard to their antioxidant activities using DPPH radicals’ cation, Trolox equivalent antioxidant capacity and ferric reducing/antioxidant power. Results from this investigation demonstrated that Moroccan Oat varieties constitute an interesting supplement of natural antioxidants, especially phenolic compounds. Moreover, potassium was the main mineral in Oat seeds (1628.17–2541.52 mg/Kg); also, the oleic, linoleic, and palmitic acids were the dominant fatty acids. While the major sterols were, β-sitosterol, Δ-5-avenasterol and campesterol. Finally, sugar analysis by HPLC-RI indicate that sucrose content was higher than glucose and fructose respectively, and that Ghali and Amlal varieties exhibit an important total sugars levels. Those results highlight the possible contributions of Oat seeds to nutritional therapy.     

The relationship between social capital and traffic law violations: Israeli Arabs as a case study

Social aspects of a community may be correlated with driver's involvement in road traffic accidents. This study focused on examining this association in the context of the social capital theory. A survey of 600 Arab drivers living in 19 towns and villages was conducted using a face-to-face interview. Structural equation modeling was applied to explore paths of associations between the model components. Most of the proposed relationships in the path model were found to be significant, where the model explained 37% of the variation. The results indicate that only volunteering and reciprocity have direct correlations with traffic law violations. While the other correlations (except political involvement), were mediated by attitudes toward traffic laws violation.     

Synthesis of multiwalled carbon nanotubes from polyethylene waste to enhance the rheological behavior of lubricating grease

Abstract

Carbon nanotubes (CNTs) are attracting great interest in enhancing rheological behavior and thermal performance of lubricating grease. In this study, CNTs were synthesized by catalytic chemical vapor deposition (CCVD) method using low-density polyethylene (LDPE) waste as a cheap carbon source and Co/MgO as an effective catalyst. The effect of temperature on the catalytic pyrolysis of LDPE to produce CNTs has been studied. Catalytic pyrolysis of LDPE waste was conducted in a temperature range of 350–600?°C using the H-ZSM-5 catalyst. The structure and quality of CNTs were fully characterized using HR-TEM, XRD, and Raman spectroscopy. On the other hand, various concentrations of CNTs (0.2, 0.4, 0.6, 0.8, and 1.0?wt%) were mixed with pure lithium grease to determine the optimum percentage that improves the properties of nano-grease. The results showed that a high yield of multiwalled carbon nanotubes (MWCNTs) was obtained with high quality at temperatures ranging from 400 to 550?°C. Also, the addition of CNTs enhanced the rheological behavior of lithium grease, and the optimum percentage of CNTs was 0.8?wt%. Furthermore, the apparent viscosity and shear stress of lithium nano-grease increased by increasing the concentration of CNTs up to 0.8%. At this concentration, the penetration value of lithium nano-grease was greater than pure grease, and the dropping point increased by 12.5%. These results suggested that CNTs prepared from LDPE waste were an excellent additive to enhance the physicochemical properties of lithium grease.     

Chitosan-based bioglass composite for bone tissue healing : Oxidative stress status and antiosteoporotic performance in a ovariectomized rat model

Tissue engineering has opened up a new therapeutic avenue promising a revolution in regenerative medicine. Considerable attention has been given to chitosan composite materials and their applications in the field of the bone graft substitutes. We evaluated the antioxidative properties of chitosan-doped bioactive glass (BG-CH) with 17 wt% chitosan, and their applications in the guided bone regeneration. BG-CH was produced by a freeze-drying process and implanted in the femoral condyles of ovariectomized rats. Grafted bone tissues were carefully removed to evaluate the oxidative stress analysis, histomorphometric profile and mineral bone distribution by using inductively coupled plasma optical emission spectrometry (ICP-OES). A significant decrease of thiobarbituric acid-reactive substances (TBARs) was observed after BG-CH implantation. Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities significantly increased in ovariectomized group implanted with chitosan-doped bioactive glass (OVXBG-CH) as compared to ovariectomized group implanted with bioactive glass (OVX-BG). The histomorphometric analysis showed that bone/tissue volume (BV/TV), osteoblast number (N.Ob) and osteoblast surface/bone surface (Ob.S/BS) were significantly higher in OVX-BG-CH group than in OVX-BG group. On the other hand, a rise in Ca and P ion concentrations in the implanted microenvironment was shown to lead to the formation/deposition of Ca-P phases. Trace elements such as Sr and Fe were detected in the newly formed bone and involved in bone healing. These results suggested that BG-CH composites could become clinically useful as a therapeutic and implantable material.     

A review on powder-based additive manufacturing for tissue engineering: selective laser sintering and inkjet 3D printing

Since most starting materials for tissue engineering are in powder form, using powder-based additive manufacturing methods is attractive and practical. The principal point of employing additive manufacturing (AM) systems is to fabricate parts with arbitrary geometrical complexity with relatively minimal tooling cost and time. Selective laser sintering (SLS) and inkjet 3D printing (3DP) are two powerful and versatile AM techniques which are applicable to powder-based material systems. Hence, the latest state of knowledge available on the use of AM powder-based techniques in tissue engineering and their effect on mechanical and biological properties of fabricated tissues and scaffolds must be updated. Determining the effective setup of parameters, developing improved biocompatible/bioactive materials, and improving the mechanical/biological properties of laser sintered and 3D printed tissues are the three main concerns which have been investigated in this article.     

Incremental learning framework for real‐world fraud detection environment

For detecting malicious bidding activities in e‐auctions, this study develops a chunk‐based incremental learning framework that can operate in real‐world auction settings. The self‐adaptive framework first classifies incoming bidder chunks to counter fraud in each auction and take necessary actions. The fraud classifier is then adjusted with confident bidders' labels validated via bidder verification and one‐class classification. Based on real fraud data produced from commercial auctions, we conduct an extensive experimental study wherein the classifier is adapted incrementally using only relevant bidding data while evaluating the subsequent adjusted models' detection and misclassification rates. We also compare our classifier with static learning and learning without data relevancy.