Insecticidal activities of essential oils from leaves of Laurus nobilis L. from Tunisia,Algeria and Morocco,and comparative chemical composition

Laurus nobilis essential oils from Tunisia, Algeria and Morocco were analyzed for their chemical composition and assessed for their repellent and toxic activities against two major stored product pests: Rhyzopertha dominica and Tribolium castaneum. The three oils showed quantitative rather than qualitative differences in their chemical compositions. 1,8-cineole, linalool and isovaleraldehyde, were identified as the major common compounds whereas, α-pinene, α-terpineol, eugenylmethylether, β-pinene, spathulenol and β-myrcene were also well represented in all three oils. Results showed that L. nobilis essential oils were repellant and toxic to adults of R. dominica and T. castaneum. Repellent and fumigant toxicities were highly dependent upon insect species and oil origin.In filter paper tests, L. nobilis essential oil from Morocco was more effective compared to Tunisian and Algerian oils. RD₅₀ values were respectively 0.013 μl/cm², 0.036 μl/cm² and 0.033 μl/cm² for R. dominica versus 0.045 μl/cm², 0.139 μl/cm² and 0.096 μl/cm² for T. castaneum. Moreover, fumigant activity tests showed that both R. dominica and T. castaneum were more susceptible to L. nobilis essential oil from Morocco than that from Algeria or Tunisia. The corresponding LC₅₀ values were respectively 68, 99 and 113 μl/l air for R. dominica against 172, 194 and 217 μl/l air for T. castaneum. Our work clearly vindicates interest in the efficacy of essential oils from plants of Mediterranean origin both as insecticides and repellents against stored product pests.     

Crystal structure and infrared spectrum of thallium holmium polyphosphate, TIHo(PO3)4

Crystals of thallium-holmium polyphosphate TIHo(PO3)4 were grown by flux method technique and characterized by single crystal X-ray diffraction. Structure of TIHo(PO3)4 was solved for the first time, and it crystallized in the monoclinic P21/n space group with the following unit-cell dimensions: a=1.02225(3) nm, b=0.88536(2) nm, c=1.09541(4) nm, β=105.888(1)°, V=0.95354(5) nm3 and Z=4. The crystal structure was solved from 2174 independent reflections with final R1(F2)=0.0442 and Rw(F<2)=0.0861 refined with 164 parameters. The atomic arrangement could be described as a long chain polyphosphate organization. Holmium atoms had eighffold coordination. The structure of T1Ho(PO3)4 consisted of HoO8 polyhedra sharing oxygen atoms with phosphoric group PO4. Infrared spectrum was investigated at room temperature in the frequencies range, 350-4000 cm-1, showing some characteristic vibration bands of infinite chain structure of PO4 tetrahedra linked by bridging oxygen.     

FRET-mediated pH-responsive dual fluorescent nanoparticles prepared via click chemistry

Herein, we report an easy preparation of azide-coated polystyrene-based nanoparticles (15 nm in diameter) and their surface functionalization via CuAAC with fluorophores in water. Resultant dual fluorescent nanoparticles coated with dansyl and pH-sensitive fluorescein moieties as the donor/acceptor FRET pair show a ratiometric response to pH upon excitation at a single wavelength.     

凝胶注模法制备多孔铝铜合金

通过凝胶注模工艺,采用非水基凝胶体系,成功地制备了铝铜合金多孔材料.通过预备试验优化工艺,采用球磨的混粉手段,球料比为1:4,球磨时间30 min,非永基凝胶体系采用1 ml单体(HEMA),8 ml溶剂(PBO),0.2 ml交联剂(DEGDA),0.02 ml催化剂-引发剂(DMA-CHP),1.2g分散剂(PVP).研究不同烧结工艺参数对材料性能的影响.结果表明,在不添加发泡剂的前提下,烧结温度660℃时,烧结体的孔隙率为42.8％.烧结体中形成的第二相CuAl2,经过热处理后可使显微硬度明显提高,最大硬度可以达到95 HV.     

Purification and characterization of an amylase from Opuntiaficus‐indica seeds

BACKGROUND: In Tunisia, prickly pear fruit grow spontaneously; it is consumed as fresh fruit, juice or jam. When the fruit is used for juice production, the seeds are discarded and go to waste. Our study aimed to extract biomolecules from seeds by producing value‐added products from the fruits. RESULTS: An amylase from Opuntia ficus‐indica seeds was extracted and purified to homogeneity. An increase in specific activity of 113‐fold was observed. The apparent molecular mass of the enzyme is 64 kDa. The optimum pH and temperature for enzyme activity were pH 5 and 60 °C, respectively. Under these conditions, the specific activity is 245.5 U mg^?1. The enzyme was activated by Co²⁺ and Mg²⁺ (relative activity 117% and 113% respectively) at lower ion concentrations. It was strongly inhibited by Mn²⁺ and Fe²⁺. Cu²⁺ inhibited totally the activity of this enzyme, but Ca²⁺ has an inhibitory effect which increases with ion concentration. CONCLUSION: The extracted enzyme belongs to the exo type of amylases and is classified as a β‐cyclodextrin glycosyltransferase since it generates mainly β‐cyclodextrin from starch. It exhibits high thermal stability and a broad range of pH stability, making it a promising prospect for industrial and food applications. Copyright © 2012 Society of Chemical Industry     

Slowing deforestation pace through subsidies: a differential game

This paper deals with the issue of deforestation, one of the main global environmental problems. We consider two players having different utilities for forest conservation. The first one (call it North) represents a set of countries having as an objective to maximize the size of tropical forest at a certain time horizon. The (South) second player's revenue function involves a trade-off between forest exploitation and agricultural activities. We study two scenarios. In the first one, the assumption is a laisser-faire policy, where the South solves an optimal control problem over a finite horizon. Revenue and optimal forest exploitation obtained represent a benchmark for the second scenario, where the North offers subsidies to the South to reduce the deforestation rate. The two scenarios are analyzed and compared in terms of strategies, outcomes and forest conservation.     

On the micro and macro perspectives of stamping engineering

Sheet metal engineering is a complex, iterative and interactive process. The whole function of stamping engineering is to select the material, devise the process, the tooling, the set-up and the operational support infrastructure to produce the final part shape, subject to part specifications, budget, and time constraints. There is little application of formal engineering science. It follows from this practice that there is a requirement for extensive die tryout and rework and there is usually little confidence that the sheet steel, the process, and tooling have been optimized. This leads to high cost, long leadtimes, schedule delays and, most important, a lack of control of the whole stamping cycle. The paper provides an overview of stamping engineering from the micro and the macro perspectives. The different engineering tasks are reviewed from a system’s perspective. The role of computer modelling is also examined, with emphasis on the applicability of the different computer tools and need for a broad methodology to support the application of the computer tools. The paper concludes by describing some of the efforts at FTI aimed at formalizing and documenting some of the stamping engineering tasks’ expertise. This work reinforces the need and the necessity for a strong relationship and interaction between the steel supplier, the lubricant supplier, the press supplier, the tooling supplier, and the stamping operation team.     

Purification of Bacillus licheniformis Lipase and its Application as an Additive in Detergent for Destaining

In this study, we aimed to optimize the nutritional and environmental conditions for the production of a novel lipase (LBL) from Bacillus licheniformis (GenBank accession no. MT118724). This strain was characterized by morphological and biochemical assays and Sanger sequencing of 16S rDNA. The crude lipolytic activity reached a maximum level 7.5 U mL⁻¹ at 40 °C and pH 8.0 using olive oil as substrate. Additionally, the crude enzyme maintained 100% of its initial activity after incubation for 1 h at 50 °C and pH 9.0. It is mandatory to note that LBL lipase displayed appreciable stability over a wide pH range and extreme temperatures. After purification, the optimal lipolytic activity was observed at pH 8.0 and 40 °C. LBL was shown to be a monomeric protein with an estimated molecular weight of 40 kDa. This novel lipase exhibited high stability and excellent compatibility compared to lipase extracted from Thermomyces lanuginosa (Lipolase® from Novozymes, Denmark) toward various detergents. Washing performance analysis revealed that it efficiently removes tomato sauce stain from cotton cloth. All these interesting enzymatic properties favor this new lipase as a potent candidate for applications in detergent formulations.     

Tracking the Genetic Susceptibility Background of B-Cell Non-Hodgkin’s Lymphomas from Genome-Wide Association Studies

B-cell non-Hodgkin’s lymphoma (NHL) risk associations had been mainly attributed to family history of the disease, inflammation, and immune components including human leukocyte antigen (HLA) genetic variations. Nevertheless, a broad range of genome-wide association studies (GWAS) have shed light into the identification of several genetic variants presumptively associated with B-cell NHL etiologies, survival or shared genetic risk with other diseases. The present review aims to overview HLA structure and diversity and summarize the evidence of genetic variations, by GWAS, on five NHL subtypes (diffuse large B-cell lymphoma DLBCL, follicular lymphoma FL, chronic lymphocytic leukemia CLL, marginal zone lymphoma MZL, and primary central nervous system lymphoma PCNSL). Evidence indicates that the HLA zygosity status in B-cell NHL might promote immune escape and that genome-wide significance variants can give biological insight but also potential therapeutic markers such as WEE1 in DLBCL. However, additional studies are needed, especially for non-DLBCL, to replicate the associations found to date.     

Process signatures in metal stamping: Basic concepts

The article establishes the basic concepts relating to a novel approach for representing grid analysis data termed “process signatures.” The process signature is the shape of the strain envelope, which depicts the strain state of contiguous elements in a stamping, corresponding to a given forming depth. Apart from inheriting unique process characteristics, the signatures represent the total response of a stamping to the punch and die actions. Reactions to fundamental modes of deformation constitute the building blocks of the signature. The practical importance of this concept stems from the fact that the fundamental blocks (modules) are unique and there is a one-to-one correspondence between areas of the process signature and the punch and die actions. It is further established that the signature responds in a predictable fashion to changes in material, lubricants, tooling clearances, blankholder forces, etc. and that because of this predictability it can be used as a powerful troubleshooting tool. Some practical examples are illustrated to demonstrate the applicability of this approach.