347 research outputs found
ToksikoloĆĄke metode otkrivanja opojnih droga u tragovima: kromatografska, spektroskopska i bioloĆĄka karakterizacija derivata ecstasyja
Analysis often reveals variability in the composition of ecstasy pills from pure 3,4-methylenedioxymethamphetamine (MDMA) to mixtures of MDMA derivatives, amphetamine, and other unidentifi ed substances. For a comprehensive toxicological analysis one needs to know all steps to MDMA synthesis which may originate impurities. The aim of this study was to synthesise and determine
the chemical-physical and in vitro biological properties of a series of MDMA derivatives. 3,4-methylendioxyphenyl-2-nitropropene (MDNP) was obtained by condensation of piperonal with an excess of nitroethane in the presence of ammonium acetate. MDNP was then reduced to methylenedioxyamphetamine (MDA) by LiAlH3. All compounds were analysed using HPLC and spectroscopic technique [Raman, nuclear magnetic resonance (NMR), or infrared (IR)] at all the steps of synthesis. In addition, we assessed the biological potentials of these compounds by measuring in vitro their
(i) blood cell/whole blood partition coeffi cient, (ii) binding to plasmatic proteins (Fbp), and (iii) membrane adsorption. Chemical structure was determined with antibody fl uorescence polarisation immunoassay (FPIA). This study showed the presence of solid impurities, particularly of a neurotoxic compound of Al3+ in the fi nal products. FPIA identifi ed the aminoethane group close to the substituted benzene ring, but did not detect the two major precursors of MDMA: MDNP and piperonal. Raman spectroscopy is an attractive alternative technique to characterise ecstasy pills and it can identify stereoisomeric forms such as cis-MDNP and trans-MDNP, which exhibit signals at 1650 cm-1 and 1300 cm-1, respectively.Analize Äesto otkriju neujednaÄenost sastava tableta ecstasyja od Äistoga 3,4-metilendioksimetamfetamina (MDMA) do mjeĆĄavina njegovih derivata, amfetamina i drugih neutvrÄenih tvari. Stoga je za kvalitetnu toksikoloĆĄku analizu potreban uvid u sve korake sinteze MDMA, s obzirom na to da se ondje vjerojatno kriju izvori neÄistoÄe (prekursori, katalizatori). Cilj ovog ispitivanja bio je sintetizirati derivate MDMA te napraviti njihovu kemijsko-fi zikalnu i bioloĆĄku in vitro karakterizaciju. 3,4-metilendioksifenil-2-nitropropen (MDNP) dobiven je kondenzacijom piperonala u suviĆĄku nitroetana uz
dodatak amonijeva acetata. Njegovom redukcijom s pomoÄu LiAlH3 dobiven je 3,4-metilendioksiamfetamin
(MDA). Svi spojevi iz pojedinih koraka sinteze karakterizirani su s pomoÄu tekuÄinske kromatografi je visoke djelotvornosti (HPLC) i spektroskopskih tehnika [Ramanove spektroskopije, nuklearne magnetske rezonancije (NMR-a) te infracrvene spektroskopije (IR-a)]. Usto je ocijenjen i njihov bioloĆĄki uÄinak in vitro mjerenjem (i) koefi cijenta raspodjele krvna stanica/puna krv, (ii) vezanja za bjelanÄevine u plazmi (Fbp) te (iii) adsorpcije na membranu. Kemijska je struktura utvrÄena s pomoÄu fl uorescentnoga polarizacijskog imunokemijskog testa (FPIA). Analiza je u konaÄnim proizvodima utvrdila prisutnost krutih neÄistoÄa, napose spojeva neurotoksiÄnog aluminija (Al3+). FPIA je prepoznao aminoetansku skupinu blizu supstituiranoga benzenskog prstena, ali ne i dva glavna prekursora za MDMA: MDNP i piperonal. Posebno je zanimljiva Ramanova spektroskopija buduÄi da (i) pruĆŸa privlaÄnu alternativu za karakterizaciju sastava tableta ecstasyja te (ii) moĆŸe otkriti stereoizomerne cis/trans-oblike spoja poput cis-MDNP-a odnosno
trans-MDNP-a, Äiji se signal vidi na 1650 cm-1 odnosno 1300 cm-1
Ăvaluation des niveaux dâexposition et des effets sur la santĂ© des travailleurs exposĂ©s aux poussiĂšres de bois dans la rĂ©gion de Sidi-Bel-AbbĂšs en AlgĂ©rie
ObjectifLâobjectif de notre enquĂȘte est dâĂ©valuer les risques et les niveaux dâexposition aux poussiĂšres de bois inhalables chez les travailleurs du bois. MĂ©thode Une enquĂȘte descriptive de type transversal a Ă©tĂ© menĂ©e sur une pĂ©riode de sept mois allant de novembre 2007 Ă mai 2008, auprĂšs des 100 menuiseries recensĂ©es au niveau de la wilaya de Sidi-Bel-AbbĂšs. Seulement 87 entreprises ont rĂ©pondu positivement Ă notre enquĂȘte, dont lâeffectif total est de 620 menuisiers. La population Ă©tudiĂ©e est constituĂ©e de 400 artisans menuisiers, exclusivement de sexe masculin rĂ©pondant au critĂšre majeur dâinclusion Ă savoir ayant plus de 70 % de leurs temps annuels de travail en atelier. Les menuisiers en pose seule ainsi que les apprentis ont Ă©tĂ© exclus de notre Ă©tude. Un questionnaire mĂ©dical pour chaque salariĂ© et un questionnaire technique au niveau de chaque entreprise ont Ă©tĂ© remplis par le mĂȘme mĂ©decin du travail chargĂ© de lâenquĂȘte, cela nous a permis une meilleure connaissance des pratiques de ces salariĂ©s et dâĂ©tablir un score dâexposition. La saisie et lâanalyse des donnĂ©es ont Ă©tĂ© faites avec SPSS.11.5. RĂ©sultats Un risque collectif moyen a Ă©tĂ© Ă©valuĂ© par le calcul des scores par entreprise. Les entreprises ont Ă©tĂ© classĂ©es en trois catĂ©gories de risque : fortâmoyenâfaible. LâĂąge moyen Ă©tait de 39,11 ± 1,19 ans, lâanciennetĂ© moyenne au poste est de 17,75 ± 0,98 ans. Les fumeurs reprĂ©sentaient 33,3 % de notre population dont 38,34 % supĂ©rieurs Ă 10 PA et avec 55 % des menuisiers qui travaillaient le bois dur. Les aspirations sur machines fixes existaient seulement dans 28 % versus 3 % sur machines portatives et uniquement 27 % des travailleurs utilisaient des moyens de protection individuels. Lâobstruction nasale restait le signe le plus rapportĂ© Ă 59 %. Conclusion Les scores laissent prĂ©voir un empoussiĂšrement excessif. Les signes irritatifs et allergiques sur le tractus des voies aĂ©riennes supĂ©rieures ont Ă©tĂ© observĂ©s. Axant nos prioritĂ©s sur la prĂ©vention et la sensibilisation des menuisiers
UV-induced modification of stress distribution in optical fibers and its contribution to Bragg grating birefringence
This paper discusses the importance of stress-induced contributions to the photo-induced birefringence observed in fiber Bragg gratings. Optical tomography measurements are performed in exposed and unexposed fibers to extract the stress profiles induced by UV-writing of fiber Bragg gratings for various exposure levels. A photoelastic analysis and a high-order isoparametric finite elements method are then used to calculate the birefringence caused by stress profile modifications. The results are compared to the birefringence directly measured by spectral analysis of a chirped fiber grating with multiple phase-shifts. We can therefore estimate the fraction of the photo-induced birefringence due to stress-induced anisotropy following UV exposure. © 2008 Optical Society of America
Impact of heavy hole-light hole coupling on optical selection rules in GaAs quantum dots
We report strong heavy hole-light mixing in GaAs quantum dots grown by
droplet epitaxy. Using the neutral and charged exciton emission as a monitor we
observe the direct consequence of quantum dot symmetry reduction in this strain
free system. By fitting the polar diagram of the emission with simple
analytical expressions obtained from kp theory we are able to extract
the mixing that arises from the heavy-light hole coupling due to the
geometrical asymmetry of the quantum dot.Comment: 4 pages, 2 figure
Fermat-linked relations for the Boubaker polynomial sequences via Riordan matrices analysis
The Boubaker polynomials are investigated in this paper. Using Riordan
matrices analysis, a sequence of relations outlining the relations with
Chebyshev and Fermat polynomials have been obtained. The obtained expressions
are a meaningful supply to recent applied physics studies using the Boubaker
polynomials expansion scheme (BPES).Comment: 12 pages, LaTe
High-level cefotaxime-resistant Proteus mirabilis strain isolated from a Tunisian intensive care unit ward: CTX-M-8 extended-spectrum ÎČ-lactamase coproduced with a plasmid mediated AmpC lactamase
The aimed of this study was to determine the implication of the biochemical and the molecular mechanism and to describe the properties of an extended-spectrum ÎČ-lactamase (ESBL) CTX-M-8 which was reported for the first time in Africa. A clinical isolate of Proteus mirabilis FS6449 was isolated from a patient hospitalized at an intensive care unit of the Military Hospital in Tunisia in 2009. Antimicrobial susceptibility was determined with the disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines and revealed that this strain was resistant to expanded-spectrum ÎČ-lactams. Analysis of P. mirabilis FS6449 by double-disk synergy test yielded a positive result suggesting the production of ESBLs. Sonicate of the isolate hydrolysed cefotaxime and benzylpenicillin. Isoelectric focusing exhibited four ÎČ-lactamase bands of isoelectric points (pIs) 5.6, 6, 6.5 and over 7.6. Polymerase chain reaction (PCR) and sequencing experiments revealed the presence of four ÎČ-lactamase genes encoding TEM-2, CTX-M-8, TEM-24, and an AmpC enzyme. Among them, the genes encoding TEM-24 and an AmpC enzyme were transferred to the recipient by conjugation experiments.Keywords: Resistance, ÎČ-lactamase, Proteus mirabilisAfrican Journal of Biotechnology Vol. 12(21), pp. 3278-328
ANALYSE ECO-BOTANIQUE COMPARATIVE DE DEUX POPULATIONS DU Pistacia atlantica EN ALGERIE PAR LE BIAIS DE MARQUEURS MORPHOLOGIQUES FOLIAIRES
RESUME
La sauvegarde des Ă©cosystĂšmes forestiers et steppiques passe nĂ©cessairement par la connaissance des exigences Ă©cophysiologiques des genres et espĂšces qui y sont largement prĂ©sents. Parmi ces espĂšces, nous citons Pistacia atlantica (pistachier de lâAtlas), ce dernier est adaptĂ© aux diffĂ©rentes conditions climatiques et se caractĂ©rise par une grande plasticitĂ©. Cette Ă©tude se propose dâidentifier cette espĂšce rustique dans son milieu naturel et permet Ă©galement dâapporter les premiers Ă©lĂ©ments de rĂ©ponses sur son comportement adaptatif vis-Ă -vis de lâenvironnement.
Ce travail vise Ă Ă©tablir une Ă©tude descriptive macro-morphologique de Pistacia atlantica, provenant de deux stations localisĂ©es sous diffĂ©rents bioclimats en AlgĂ©rie, avec une analyse de la variabilitĂ© morphologique intra et inter-populations par lâutilisation dâun total de 15 caractĂšres quantitatifs et qualitatifs morphologiques des feuilles dans le but dâidentifier et de mieux connaitre lâespĂšce, ce qui permet de conserver la diversitĂ© gĂ©nĂ©tique de cette espĂšce autochtone qui reste mĂ©connue et par consĂ©quent trĂšs peu employĂ©e dans la prĂ©servation des Ă©cosystĂšmes forestiers et prĂ©-forestiers malgrĂ© ses intĂ©rĂȘts, aussi bien Ă©cologique qu'Ă©conomique.
Lâanalyse statistique a permis de sĂ©parer les populations Ă©tudiĂ©es en deux groupes selon les variables Ă©tudiĂ©es et les conditions climatiques. Les dimensions des feuilles, le nombre de paires de folioles, longueur du pĂ©tiole, la forme de la foliole terminale, la forme du pĂ©tiole et la prĂ©sence de trichomes, sont les caractĂ©ristiques les plus discriminantes. De mĂȘme, les diffĂ©rentes adaptations observĂ©es lors de cette Ă©tude (variation dans la taille des feuilles) peuvent sâexpliquer par la plasticitĂ© et la prĂ©sence de cette espĂšce dans diverses conditions climatiques.
Mots clES: Algérie, feuille, macromorphologie, micromorphologie, Pistacia, trichomes, variabilité.
ABSTRACT
The protection of the forest and steppe ecosystems takes place inevitably by the knowledge of the genus and the species ecophysiological requirements which are widely present there. Among these species, we quote Pistacia atlantica (Atlas pistachio), which is adapted to the various weather conditions and is characterized by its big plasticity. This study suggests identifying this rustic species in its natural environment and also provides the first elements of answers on its adaptive behavior towards the environment.
This work aims at establishing a macro-morphological descriptive study of Pistacia atlantica, resulting from two stations located under various bioclimates in Algeria, with an analysis of morphological variability intra and inter-populations using a total of 15 quantitative and qualitative morphological characters of leaves with the aim of identifying and knowing better the species, which make it possible to preserve the genetic diversity of this native and autochthonous species which remains underestimated and consequently very little used in the conservation of the forest and pre-forest ecosystems in spite of its interests, so ecological as economic.
The statistical analysis allowed to separate the populations studied in two groups according to the studied variables and the weather conditions. The size of leaves, number of pairs of sepals, length of the petiole, shape of the terminal sepal, shape of the petiole and the presence of trichomes, are the most discriminating characteristics. Also, the various adaptations observed during this study (variation in the size of leaves) can be understandable by the plasticity and the presence of this species in various climatic conditions
A comparison of electrochemical degradation of phenol on boron doped diamond and lead dioxide anodes
This work compares two electrode materials used to mineralize phenol contained in waste waters. Two disks covered with either boron doped diamond (BDD) or PbO2 were used as anodes in a one compartment flow cell under the same hydrodynamic conditions. Efficiencies of galvanostatic electrolyses are compared on the basis of measurements of Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD). Galvanostatic electrolyses were monitored by analysis of phenol and of its oxidation derivatives to evaluate the operating time needed for complete elimination of toxic aromatics. The experimental current efficiency is close to the theoretical value for the BDD electrode. Other parameters being equal, phenol species disappeared at the same rate using the two electrode materials but the BDD anode showed better efficiency to eliminate TOC and COD. Moreover, during the electrolysis less intermediates are formed with BDD compared to PbO2 whatever the current density. A comparison of energy consumption is given based on the criterion of 99% removal of aromatic compounds
Efficient Delivery of Hydrophilic Small Molecules to Retinal Cell Lines Using Gel Core-Containing Solid Lipid Nanoparticles
In this study, we developed a novel solid lipid nanoparticle (SLN) formulation for drug delivery of small hydrophilic cargos to the retina. The new formulation, based on a gel core and composite shell, allowed up to two-fold increase in the encapsulation efficiency. The type of hydrophobic polyester used in the composite shell mixture affected the particle surface charge, colloidal stability, and cell internalization profile. We validated SLNs as a drug delivery system by performing the encapsulation of a hydrophilic neuroprotective cyclic guanosine monophosphate analog, previously demonstrated to hold retinoprotective properties, and the best formulation resulted in particles with a size of ±250 nm, anionic charge > â20 mV, and an encapsulation efficiency of ±60%, criteria that are suitable for retinal delivery. In vitro studies using the ARPE-19 and 661W retinal cell lines revealed the relatively low toxicity of SLNs, even when a high particle concentration was used. More importantly, SLN could be taken up by the cells and the release of the hydrophilic cargo in the cytoplasm was visually demonstrated. These findings suggest that the newly developed SLN with a gel core and composite polymer/lipid shell holds all the characteristics suitable for the drug delivery of small hydrophilic active molecules into retinal cells
Optimising LeadâAir Battery Performance through Innovative Open-Cell Foam Anodes
\ua9 2024 by the authors.In the dynamic realm of sustainable energy storage technologies, the global research landscape presents myriad scientific and economic challenges. The erratic growth of renewable energies alongside the phasing out of conventional power plants poses a significant hurdle in maintaining a stable balance between energy supply and demand. Consequently, energy storage solutions play a pivotal role in mitigating substantial fluctuations in demand. Metalâair batteries, distinguished by their superior energy density and enhanced safety profile compared to other storage devices, emerge as promising solutions. Leveraging the well-established leadâacid battery technology, this study introduces a novel approach utilising open-cell foam manufactured through the Excess Salt Replication process as an anode for leadâair battery cells. This innovation not only conserves lead but also reduces battery weight. By employing a 25% antimonial lead alloy, open-cell foams with diameters ranging from 2 mm to 5 mm were fabricated for the antimonial leadâair battery. Preliminary findings suggest that the effective electrical conductivity of primary battery cells, measured experimentally, surpasses that of cells composed of the same dense, non-porous antimonial lead alloy. This improvement is primarily attributed to their extensive specific surface area, facilitating oxidationâreduction reactions. A correlation between effective electrical conductivity and cell diameter is established, indicating optimal conductivity achieved with a 5 mm cell diameter. These results underscore the feasibility of implementing such an electrical system
- âŠ