Asymmetric reduction of ketones by biocatalysis using clementine mandarin (Citrus reticulata) fruit grown in Annaba or by ruthenium catalysis for access to both enantiomers.

Biocatalytic reduction of prochiral ketones using freshly ripened clementine mandarin (Citrus reticulata) in aqueous medium is reported. High enantioselectivities were observed, especially for the bioreduction of indanone , tetralone , and thiochromanone with respectively 95%, 99%, and 86% enantiomeric excess (ee). Enantioselective bio- and metal-catalyzed reactions were compared.

A method for predicting the number of active bubbles in sonochemical reactors.

Knowledge of the number of active bubbles in acoustic cavitation field is very important for the prediction of the performance of ultrasonic reactors toward most chemical processes induced by ultrasound. The literature in this field is scarce, probably due to the complicated nature of the phenomena. We introduce here a relatively simple semi-empirical method for predicting the number of active bubbles in an acoustic cavitation field.

Sensitivity of free radicals production in acoustically driven bubble to the ultrasonic frequency and nature of dissolved gases.

Central events of ultrasonic action are the bubbles of cavitation that can be considered as powered microreactors within which high-energy chemistry occurs. This work presents the results of a comprehensive numerical assessment of frequency and saturating gases effects on single bubble sonochemistry. Computer simulations of chemical reactions occurring inside a bubble oscillating in liquid water irradiated by an ultrasonic wave have been performed for a wide range of ultrasonic frequencies (213-1100kHz) under different saturating gases (O2, air, N2 and H2).

Variability of the dissolved nutrient (N, P, Si) concentrations in the Bay of Annaba in relation to the inputs of the Seybouse and Mafragh estuaries.

Dissolved inorganic nitrogen (DIN), phosphate (PO₄) and silicic acid (Si(OH)₄) loads from the Seybouse and the Mafragh estuaries into the Bay of Annaba, Algeria, were assessed at three stations of the Bay over three years. The Seybouse inputs had high levels of DIN and PO₄, in contrast to the Mafragh estuary's near-pristine inputs; Si(OH)₄ levels were low in both estuaries. The DIN:PO₄ molar ratios were over 30 in most samples and the Si(OH)4:DIN ratio was less than 0.

Purification and biochemical characterization of a detergent-stable keratinase from a newly thermophilic actinomycete Actinomadura keratinilytica strain Cpt29 isolated from poultry compost.

An extracellular thermostable keratinase (KERAK-29) was purified and biochemically characterized from a thermophilic actinomycete Actinomadura keratinilytica strain Cpt29 newly isolated from Algerian poultry compost. The isolate exhibited high keratinase production when grown in chicken feather meal media (24,000 U/ml). Based on matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis, the purified enzyme is a monomer with a molecular mass of 29,233.

Removal of non-steroidal anti-inflammatory drugs ibuprofen and ketoprofen from water by emulsion liquid membrane.

In this work, the removal of the worldwide non-steroidal anti-inflammatory drugs ibuprofen (IBP) and ketoprofen (KTP) by emulsion liquid membrane (ELM) was carried out. An ELM system is made up of hexane as diluent, Span 80 as the surfactant and sodium carbonate as the inner aqueous solution. Effect of experimental conditions that affect the extraction of IBP such as surfactant concentration, emulsification time, sulfuric acid concentration in external phase, acid type in external phase, internal phase concentration, type of internal phase, stirring speed, volume ratio of internal phase to membrane phase, treatment ratio, IBP initial concentration, diluent type and salt was investigated.

Theoretical estimation of the temperature and pressure within collapsing acoustical bubbles.

Formation of highly reactive species such as OH, H, HO2 and H2O2 due to transient collapse of cavitation bubbles is the primary mechanism of sonochemical reaction. The crucial parameters influencing the formation of radicals are the temperature and pressure achieved in the bubble during the strong collapse. Experimental determinations estimated a temperature of about 5000 K and pressure of several hundreds of MPa within the collapsing bubble.

Energy analysis during acoustic bubble oscillations: relationship between bubble energy and sonochemical parameters.

In this work, energy analysis of an oscillating isolated spherical bubble in water irradiated by an ultrasonic wave has been theoretically studied for various conditions of acoustic amplitude, ultrasound frequency, static pressure and liquid temperature in order to explain the effects of these key parameters on both sonochemistry and sonoluminescence. The Keller-Miksis equation for the temporal variation of the bubble radius in compressible and viscous medium has been employed as a dynamics model. The numerical calculations showed that the rate of energy accumulation, dE/dt, increased linearly with increasing acoustic amplitude in the range of 1.

Effects of ultrasound frequency and acoustic amplitude on the size of sonochemically active bubbles - Theoretical study.

Numerical simulation of chemical reactions inside an isolated spherical bubble of oxygen has been performed for various ambient bubble radii at different frequencies and acoustic amplitudes to study the effects of these two parameters on the range of ambient radius for an active bubble in sonochemical reactions. The employed model combines the dynamic of bubble collapse with the chemical kinetics of single cavitation bubble. Results from this model were compared with some experimental results presented in the literature and good apparent trends between them were observed.

Antibacterial and antioxidant activities of three endemic plants from Algerian Sahara.

Background: Saharan plants are known by their high content of antioxidant products like phenolic compounds due to the extreme climatic conditions. They constitute the basis of treatments used by local population for various diseases. The purposes of this study were to measure the total phenolic compounds and total fl avonoid compounds, to determine antioxidant capacity, and to evaluate the antibacterial activity of three wild Saharan medicinal plants.

N-tert-Butoxycarbonylation of Structurally Diverse Amines and Sulfamides under Water-Mediated Catalyst-Free Conditions.

A simple, efficient, and eco-friendly protocol for the N-Boc protection of the amine moiety in a variety of compounds with di-tert-butyl dicarbonate under water-acetone catalyst-free conditions is described. The corresponding monocarbamate is obtained in excellent yields on short reaction times. No competitive side reactions such as isocyanate urea and O-Boc were observed.

Purification and biochemical characterization of a highly thermostable xylanase from Actinomadura sp. strain Cpt20 isolated from poultry compost.

An extracellular thermostable xylanase from a newly isolated thermophilic Actinomadura sp. strain Cpt20 was purified and characterized. Based on matrix-assisted laser desorption-ionization time-of-flight mass spectrometry analysis, the purified enzyme is a monomer with a molecular mass of 20,110.

Effects of two systemic fungicides: Artea (Propiconazole+cyproconazole) and Punch (Flusilazole) on the physiology and the respiratory metabolism of durum wheat (Triticum durum L.).

The present work aimed at the study of the effects of Artea and Punch; two systemic fungicides on durum Wheat (Triticum durum L. cv. GTA dur).

Extraction of atropine by ultrasounds in different solvent systems.

The use of ultrasounds for extraction of atropine from Egyptian henbane (Hyoscyamus muticus) has been studied. The kinetic of extraction using various solvent systems was carried out. The results obtained have shown that the most efficient system of solvents was CH3OH/CH3CN (80:20).

Computed tomography of the brain in eclampsia.

Computed tomography (CT) of the brain was performed on 44 women with eclampsia, 31 during pregnancy and 13 postpartum. All CT scans were done within 24 hours of eclampsia, including 12 within 1 hour of the convulsions and eight before the repetition of additional seizures, 2 minutes to 14 hours later. Control scans were performed on 15 hypertensive pregnant patients and on ten normotensive pregnant women after fetal death or just after delivery.