Chemical composition and antioxidant activity of Borago officinalis L. leaf extract growing in Algeria

The aqueous and hydroalcoholic extracts of borage (Borago officinalis) leaves from Annaba region (Algeria) were preliminary analyzed for their phenolic profile (total phenolics, total flavonoids, total flavonols, total tannins and total anthocyanins). These extracts were evaluated for their antioxidant properties by different methods such as DPPH radical scavenging, test NBT and total antioxidant activity. The two extracts have exhibited a high antiradical capacity. Indeed, the ethanolic extract showed the lower IC50 values and the highest amount of phenolics (94.09 ± 1.72 mg gallic acid/g dry extract). Using LC-MS/MS analysis, it was possible to identify phenolic acids, flavonoids, sterol and for the first time oleuropein was identified in the aqueous extract of the plant. The obtained results have demonstrated that phenolic compounds are the major contributor to the antioxidant activity of plants.     

Petrographic, chemical and microprobe analysis of an oxidized iron nodule from Dahr Safra, NW Syria: Is it an iron ore, or a meteorite called shale-ball?

The iron nodule DS-S revealed the concentrations of Ni, Co, Ga, Ge, As, Sb, P, S, many trace and rare earth elements, Fe (> 93 wt.%), and 2 wt.% silicates. The plotting of Ga, Ge, Cr, Cu, As, Au, W, and Ir-concentrations vs. Ni/Co in the classes (groups) IIAB, IIIAB, IVA, ungrouped (ung), NBS 809B steel (st), and DS-S, confirmed the meteoritic origin for DS-S. Magnetite-hematite resulted from oxidation during the melting/solidification process of the original meteorite across the atmosphere. The silicates suggested the presence of Ca-rich plagioclase, and traces of opx, cpx, and/or olivine which explained the low concentrations of Ni-Co. The plotting of Ga/Ge vs. Ni/Co; Ni/Co, Ga vs. P; and Ni/Co, Ga/Ge vs. As revealed the affinity of the DS-S nodule with the ungrouped Bellsbank trio. The compositional homogeneity in the DS-S nodule was probably due to O-fugacity. The conformable REE-graphs, for chondrite and DS-S, and the presence of silicates with the same phases suggested a mesosideritic origin for DS-S.     

Petrographic/geochemical studies of primary and alteration–weathering minerals in garnetiferous ultramafic xenoliths–basanite, Tartous Province, NW Syria

Kimberlitic–pyropic peridotite–xenolites, probably of Jurassic–Cretaceous age, were found mixed with a younger Upper Tertiary basanitic diabase, as flow texture of plagioclase laths and ilmenite rods around those xenoliths indicated. Mafic–ultramafic rocks were crushed, sheared, and cropped along a creek about 15–18 km NE of the town of Dreikeesh, NW Syria. ⁴⁰K–⁴⁰Ar isotopic dating of a pure fresh black cpx sample, collected from the peridotite xenoliths, yielded an age of about 70 Ma. This age is concurrent to the time when Africa, Eurasia, and America were part of the super continent Pangaea. It also suggests that kimberlite–pyropic peridotitic rocks were located within a cratonic pipe prior to their 2000-km eastward journey (starting from the Mid-Atlantic Rift). Sampled outcrops were located within a ring of about 40 km diameter, considered to be a dome consisting of one or more clusters of kimberlitic pipes. The dome structure, mostly covered with Upper Jurassic–Cretaceous carbonate beds, was tilted westward, and rifted and sheared along its eastern edge. Tilting and crushing were accomplished after the opening of the Red Sea in the Miocene, and the counterclockwise movements of the Arabian plate, which folded the carbonate beds to form the N–S-trending Alawite mountain range along the Syrian coast. Olivine, cpx, and pyrope were the major phases in peridotite. Pyrope, including its Cr–Ni-contents, was found to be the best indicator to decipher the temperature–pressure (T–P) conditions for the system. The inferred temperature was found to be about 1460 °C, at a pressure of 62 kb (around 207 km-depth). Petrographic studies revealed many zoned, resorbed, octahedral and non-metasomatized tiny grains, associated with partly to wholly metasomatized and iddingsitized olivines.     

Role of water vapor and CO2 in the paleoclimatic fluctuations along northwestern and southern Syria, and the adjacent Mediterranean Sea

Microscopic petrified grains were collected from a mafic–ultramafic pipe, NE of Dreikeesh, NW Syria. The grains were identified as anthers/gynoecia in herb/grass flowers. Three of the grains showed evidence of magnetism, two slowly dissolved in concentrated HCl, and three microprobed grains showed a montmorillonitic composition. Iron originating from pyroxene was oxidized to magnetite. Released silica formed the mineral suite agate–chalcedony–opal. Warm/cold paleoclimatic fluctuations, occurring during late Pliocene–Holocene, depended on water vapor, CO₂ production, and cinders in the atmosphere. Most of these were associated with changing volcanic/tectonic events. Fluctuations were controlled by heat reflected from the Earth's surface being absorbed by water vapor and CO₂, which both re-reflected the heat back to the surface, thus, raising the temperature. This cycle was repeated several times during late Pliocene–Holocene.     

Oscillation theorems for a second order delay differential equation

A generalized version is proved of the following inequality, arising in a study of invertible measure preserving transformations: $\text{(∑}{}_{\mathrm{i\; =\; 1}}{}^{\mathrm{N}}\text{x}{}_{\mathrm{i}}{}^{\mathrm{n}}\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>n</mtext>}}\text{(∑}{}_{\mathrm{i\; =\; 1}}{}^{\mathrm{N}}\text{x}{}_{\mathrm{i}}{}^{\mathrm{m}}\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>m</mtext>}}\text{? (∑}{}_{\mathrm{i\; =\; 1}}{}^{\mathrm{N}}\text{x}{}^{\mathrm{mn}}\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>mn</mtext>}}\text{(∑}{}_{\mathrm{i\; =\; 1}}{}^{\mathrm{N}}\text{x}{}_{\mathrm{i}}\text{),}\text{where}\text{x}{}_{\mathrm{i}}\text{? 0, i = 1, 2,…, N,}\text{and}\text{(m ? 1)(n ? 1) > 0}$.     

Comparative study of catalytic activity of Pd loaded hydroxyapatite and fluoroapatite in butan-2-ol conversion and methane oxidation

Palladium loaded calcium-hydroxyapatite, Pd(z)/CaHAp, and calcium-fluoroapatite, Pd(z)/CaFAp, were synthesised and characterised by TEM, XRD, IR and UV–vis–NIR spectroscopies. Introduction of palladium does not change the structure of CaHAp and CaFAp. The average size of PdO particles was found to be around 4–5 nm on Pd(1)/CaHAp but larger (6–7 nm) on Pd(1)/CaFap. The acid–base properties of the supports and of the catalysts were studied using butan-2-ol conversion. On CaHAp and CaFAp, the butenes yield (dehydration reaction) is very low either in the absence or in the presence of oxygen. The methyl ethyl ketone yield (dehydrogenation reaction) is significant only in the presence of oxygen and higher over CaFAp. Conversely, the performances of Pd(z)/CaHAp are better than those of Pd(z)/CaFAp below 180 °C. Above 180 °C, buta-2-ol combustion is favoured on Pd/CaHAp but not on Pd/CaFAp.

In methane oxidation, Pd(z)/CaHAp showed also a much larger activity than Pd(z)/CaFAp. On 2 wt% Pd loaded CaHAp, the methane oxidation reaches a conversion of almost 100% at 350 °C, which is comparable with the performance of conventional Pd/Al₂O₃ catalysts. The reducibility of PdO under methane–oxygen mixtures is lower on Pd(z)/CaHAp. For both reactions, the lower activity of Pd(z)/CaFAp is related to its higher acidity, resulting from the substitution of OH⁻ by F⁻, and to the larger PdO particle size.     

Effect of electromagnetic actuations on the dynamics of a harmonically excited cantilever beam

The influence of electromagnetic actuators (EMAs) on the frequency response of a harmonically excited cantilever beam is investigated analytically, numerically and experimentally in this paper. Specifically, the intensity of the current generating the EMAs force is varied and its effect on the dynamic behavior of the system is analyzed. Analytical treatment based on perturbation analysis is performed on a simplified equation modeling the one mode vibration of the cantilever beam. Results indicated that EMAs produce a softening behavior in the system. Further, it is shown that as the current intensity of EMAs increases, the resonance curve shifts toward smaller values of frequency and the non-linear characteristic of the system becomes softer. The analytical predictions have been verified numerically and confirmed experimentally using a test rig.     

Enlarging the library of poly‐(L‐lysine citramide) polyelectrolytic drug carriers

Poly‐(L ‐lysine citramide) is a degradable drug carrier of the polyelectrolyte type that is composed of citric acid and L ‐lysine building blocks. In a previous work, poly‐(L ‐lysine citramide) was synthesized by the interfacial polycondensation of α‐hydroxy acid protected citryl dichloride with COOH‐protected lysine diamine. Because of head‐to‐head and head‐to‐tail and tail‐to‐tail linkages in the chains as well as various side reactions such as deprotection of the α‐hydroxy acid moieties and intramolecular imide ring formation, a very large family of degradable polyelectrolyte copolymers was obtained. All the members of this family hydrolytically degrade to the same end products. In this study, another route was explored based on the polycondensation of α‐hydroxy acid protected citric acid pentafluorophenyl diesters, namely, citrobenzal dipentafluorophenyl and citrochloral dipentafluorophenyl with N‐N′‐trimethylsilylated COOH‐protected L ‐lysine. The resulting polymers were characterized by IR, NMR, and size exclusion chromatographic analyses. The resulting chain structures and repeat units were identified from these characterizations and are discussed as compared with characteristics exhibited by analogous polymers resulting from interfacial polycondensation. Differences observed at the intermediate stage involving protected polymers were largely erased during the final deprotection stage because of imide formation during final hydrolysis under the selected conditions. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3475–3484, 2001     

A simple Abel inversion method of interferometric data for temperature measurement in axisymmetric medium

In this work, we describe a simple method of Abel inversion for temperature measurement in a natural convection axisymmetric flow. The essence of the method is that the measured lateral fringe shift profile is fitted with a polynomial with only even powers and then Abel inverse integral is evaluated analytically. This technique is compared with recent existing methods to test the accuracy and error propagation using a simulated interferogram of natural convection flow below a downward-facing heated horizontal disk in air. For this comparison, lateral fringe profiles are simulated using temperature fields computed by solving Navier Stokes and energy equations. Through random-number generation, noise profile is artificially added to the simulated noise-free lateral fringe shift profile. The results showed that the proposed technique for Abel inversion leads to accurate temperature profiles when the lateral fringe shift profile is fitted with even-power polynomials having degrees ranging from 20 to 30.