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501.
The analytical behaviour of the relatively new pyrethroid insecticide tralomethrin has been evaluated by using gas chromatography (GC) with electron-capture and mass spectrometry (MS) detectors, and liquid chromatography (LC)-atmospheric pressure ionization mass spectrometry with electrospray interfacing. Under the GC conditions commonly used in pesticide residue analysis, it was found that tralomethrin is transformed into deltamethrin (in a reproducible way) in the injector port of the GC system. Results obtained in this work indicate that the GC multiresidue methodologies routinely applied in the analysis of pyrethroid pesticides in foods cannot distinguish between these two pesticides, and the chromatographic signal obtained at the retention time of deltamethrin/tralomethrin can be really quantified as either deltamethrin or tralomethrin, including when it is confirmed as deltamethrin by MS. Under the LC-MS conditions assessed in this work, deltamethrin and the two diasteroisomers of tralomethrin were well separated and identified. 相似文献
502.
A. A. Hassan N. K. Mohamed A. A. Aly A. -F. E. Mourad 《Monatshefte für Chemie / Chemical Monthly》1997,128(1):61-70
Summary The reaction of thiocarbohydrazides1a and thiocarbazones1b with tetracyanoethylene (TCNE) afforded the thiazol, thiadiazole, thiazine, and thiadiazepine derivatives4–7. 2-Dicyanomethyleneindane-1,3-dione (CNIND) reacted with1a,b to give aminoindenopyrazolopyridazinone (12) and phenyl-1,2,3,4-tetraazacyclopentafluorene (13). The indazole and oxathiadiazole derivatives17 and19 were formed during the reaction of1b with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDO). 6,7-Dichloro-5-phenylpyrazolophthalazinol (21) was obtained from the reaction of1b with 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL-p). The oxidative cyclization of thiodicarbazones2a–d with the above acceptors afforded the thiadiazole and thiadiazine derivatives8 and10.
Eine neue Synthese von Heterocyclen aus Thiocarbohydraziden
Zusammenfassung Die Reaktion der Thiocarbohydrazide1a und der Thiocarbazone1b mit Tetracyanoethylen (TCNE) ergab die Thiazol-, Thiadiazol-, Thiazin- und Thiadiazepinderivate4–7. 2-Dicyanomethylenindan-1,3-dion (CNIND) liefert mit1a,b Aminoindenopyrazolopyridazinon (12) und Phenyl-1,2,3,4-tetraazacyclopentafluoren (13). Die Indazol- und Oxathiadiazolderivate17 und19 wurden durch Reaktion von1b mit 1,3-Dichlor-5,6-dicyano-1,4-benzochinon (DDQ) gebildet. 6,7-Dichlor-5-phenylpyrazolophthalazinol (21) wurde aus1b und 2,3,5,6-Tetrachlor-1,4-benzochinon (CHL-p) erhalten. Die oxidative Cyclisierung der Thiodicarbazone2a–d mit den obengenannten Akzeptoren ergab die Thiadiazol- und Thiadiazinderivate8 und10.相似文献
503.
Lara L. Reys Vijayaganapathy Vaithilingam Mireille M. J. P. E. Sthijns Eduardo Soares Timo Rademakers Rick de Vries Sami G. Mohammed Denise de Bont Marlon J. Jetten Carolin Hermanns Omar Paulino da Silva Filho Adam Stell Nizar I. Mourad Pierre Gianello Vanessa L. S. LaPointe Simone S. Silva Rui L. Reis Tiago H. Silva Aart A. van Apeldoorn 《Advanced functional materials》2021,31(35):2011205
Microencapsulating pancreatic islets in immunoprotective alginate hydrogels is a promising strategy for treatment of type 1 diabetes. However, this strategy is limited by inflammation and hypoxia mediated oxidative stress, due to encapsulation and the hydrogel itself, leading to impaired insulin secretion and limited short and long term cell survival. Herein, the antioxidant effect of fucoidan, an algae derived polysaccharide, on beta cells, and its positive effects on encapsulated beta cell viability and function is presented. Fucoidan from Fucus vesiculosus (FF) exhibits a high total antioxidant capacity, and free radical scavenging activity, and is able to significantly alleviate intracellular oxidative stress in rat insolinoma beta cells (INS1E). In addition, FF significantly increases insulin secretion in a dose- and time-dependent manner. When FF is incorporated in ultrapure alginate used for microencapsulation of primary rat islets, both viability and glucose responsiveness of rat islets in these socalled Fucogel microcapsules (Fucocaps) are found to be significantly higher compared to islets encapsulated in alginate alone. Similar results are obtained with INS1E pseudoislets and neonatal pig islets. Fucocaps can provide a redox-modulatory niche and an immune barrier for islets and beta cells in the same time leading to significantly improved survival and endocrine function by mitigating oxidative stress. 相似文献
504.
Lahiani Sawssen Daoud Houda Ben Salem Samir Aloulou Rahma Loulou Mourad 《Analog Integrated Circuits and Signal Processing》2021,107(3):529-542
Analog Integrated Circuits and Signal Processing - In this study, a novel single-stage Digital Variable Gain Amplifier architecture (DVGA) was presented for Long Time Evolution (LTE) receivers. The... 相似文献
505.
Alberto Santos Mohamed Ajbary José A. Toledo-Fernández Víctor Morales-Flόrez Abdelhak Kherbeche Luis Esquivias 《Journal of Sol-Gel Science and Technology》2008,48(1-2):224-230
Synthetic wollastonite has been used as the active phase embedded into two different silica aerogel composites. These composites are different in respect of the route used for the synthesis of the wollastonite powder. Texture and composition of both types of composite have been characterized. In addition, several factors (pH, reaction time, CO2 saturation, etc.) that could help to optimize the carbonation process at room temperature and pressure have been studied. Under the same conditions, both composites confirm previous results showing efficiencies as CO2 sequesters between 80% and 100% in only 15 min of gas flow. The textural characteristics of the aerogel, together with the grain size of the synthetic wollastonite powder, not only increase the speed of the reaction, but also inhibit the appearance of a passivating layer on the surface of the wollastonite grains attacked by the CO2. This is an outstanding feature as it insists on a cutting-edge challenge of the CO2 research: its economical availability. 相似文献
506.
507.
Mourad Bellassoued Masahiro Yamamoto 《Journal of Mathematical Analysis and Applications》2007,329(2):1240-1259
We consider an inverse problem of determining spatially varying density and two Lamé coefficients in a non-stationary isotropic elastic equation by a single measurement of data on the whole lateral boundary. We prove the Lipschitz stability provided that initial data are suitably chosen. The proof is based on a Carleman estimate which can be obtained by the decomposition of the Lamé system into the rotation and the divergence components. 相似文献
508.
Feel like writing a review for The Mathematical Intelligencer? You are welcome to submit an unsolicited review of a book of your choice; or, if you would welcome being assigned a book to review, please write us, telling us your expertise and your predilections. 相似文献
509.
Naofumi Honda Gen Nakamura Roland Potthast Mourad Sini 《Annali di Matematica Pura ed Applicata》2008,187(1):7-37
This paper addresses the inverse obstacle scattering problem. In the recent years several non-iterative methods have been
proposed to reconstruct obstacles (penetrable or impenetrable) from near or far field measurements. In the chronological order,
we cite among others the linear sampling method, the factorization method, the probe method and the singular sources method.
These methods use differently the measurements to detect the unknown obstacle and they require the use of many incident fields
(i.e. the full or a part of the far field map). More recently, two other approaches have been added. They are the no-response
test and the range test. Both of them use few incident fields to detect some informations about the scatterer. All the mentioned
methods are based on building functions depending on some parameter. These functions share the property that their behaviors
with respect to the parameter change drastically. The surface of the obstacle is located at most in the interface where these
functions become large. The goal of this work is to investigate the relation between some of the non-iterative reconstruction
schemes regarding the convergence issue. A given method is said to be convergent if it reconstructs a part or the entire obstacle
by using few or many incident fields respectively. For simplicity we consider the obstacle reconstruction problem from far
field data for the Helmholtz equation.
Gen Nakamura is partially supported by Grant-in-Aid for Scientific research (B)(2)(N.14340038) of Japan Society for Promotion
of Science.
Mourad Sini is supported by Japan Society for Promotion of Science. 相似文献
510.
Mourad H.M. Al-Bassiouni A.A.M. Emam S.S. Al-Hussaini E.K. 《Communications Letters, IEEE》2001,5(10):405-407
A novel three-dimensional distribution traffic is proposed for low Earth orbit (LEO) satellite systems. The effect of the traffic geographical nonuniformity on the performance of these satellite systems is discussed 相似文献