Home About us Contact
|
Home About us Contact | ||
|
|
||
Efficient Procedure (efficient + procedure)
Kinds of Efficient Procedure Selected AbstractsChemInform Abstract: A Simple and Efficient Procedure for the Synthesis of Ketone Di-sec-alkyl Acetals.CHEMINFORM, Issue 26 2009Fumiaki Ono Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: An Efficient Procedure for the Synthesis of 2-N-Boc-amino-3,5-diols.CHEMINFORM, Issue 43 2008Luiz C. Dias Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Efficient Procedure for Chemoselective N-Nitrosation of Secondary Amines with Trichloromelamine,NaNO2.CHEMINFORM, Issue 8 2008A. Bamoniri Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Practical and Efficient Procedure for Reduction of Carboxylic Acids and Their Derivatives: Use of KBH4,MgCl2.CHEMINFORM, Issue 5 2008You-Chun Qiu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Ru(IV)-Catalyzed Isomerization of Allylamines in Water: A Highly Efficient Procedure for the Deprotection of N-Allylic Amines.CHEMINFORM, Issue 51 2005Victorio Cadierno Abstract For Abstract see ChemInform Abstract in Full Text. [source] An Efficient Procedure for the Preparation of 4-Methyl-2-thiocoumarins by the Reaction of 4-Methylcoumarins with Lawesson,s Reagent.CHEMINFORM, Issue 41 2005Albert Levai Abstract For Abstract see ChemInform Abstract in Full Text. [source] Hydrazine Hydrate Induced Reductive Cleavage of ,,,-Epoxy Ketones: An Efficient Procedure for the Preparation of ,-Hydroxy Ketones.CHEMINFORM, Issue 22 2005Jorge A. R. Salvador Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Mild and Efficient Procedure for the Synthesis of 1-(Alkyldithiocarbonyl)-imidazoles.CHEMINFORM, Issue 33 2004Yi-Qiang Wang Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Facile and Efficient Procedure for Deprotection of 1,1-Diacetates Catalyzed by H2NSO3H.CHEMINFORM, Issue 26 2003Tong-Shou Jin Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Highly Efficient Procedure for Regeneration of Carbonyl Groups from Their Corresponding Oxathioacetals and Dithioacetals Using Sodium Nitrite and Acetyl Chloride in Dichloromethane.CHEMINFORM, Issue 23 2003Abu T. Khan Abstract For Abstract see ChemInform Abstract in Full Text. [source] An Efficient Procedure for the Preparation of (E)-,-Alkylidenecycloalkanones Mediated by a CeCl3×7H2O,NaI System.CHEMINFORM, Issue 17 2003Novel Methodology for the Synthesis of (S)-(-)-Pulegone. Abstract For Abstract see ChemInform Abstract in Full Text. [source] A general framework for evaluating nonlinearity, noise and dynamic range in continuous-time OTA-C filters for computer-aided design and optimizationINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 4 2007S. Koziel Abstract Efficient procedures for evaluating nonlinear distortion and noise valid for any OTA-C filter of arbitrary order are developed based on matrix description of a general OTA-C filter model. Since those procedures use OTA macromodels, they allow us to obtain the results significantly faster than transistor-level simulation. On the other hand, the general OTA-C filter model allows us to apply matrix transforms that manipulate (rescale) filter element values and/or change topology without changing its transfer function. Due to this, the proposed procedures can be used in direct optimization of OTA-C filters with respect to important characteristics such as noise performance, THD, IM3, DR or SNR. As an example, a simple optimization procedure using equivalence transformations is discussed. An application example of the proposed approach to optimal block sequencing and gain distribution of 8th order cascade Butterworth filter is given. Accuracy of the theoretical tools has been verified by comparing to transistor-level simulation results and to experimental results. Copyright © 2006 John Wiley & Sons, Ltd. [source] Denitrocyclization in synthesis of dibenzo[b,f][1,4]thiazepin-11(10h)-ones and their derivativesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2007Alexey V. Smirnov A convenient synthesis of the novel dibenzo[b,f][1,4]thiazepin-11(10H)-ones is reported. As a key step, the synthetic route includes intramolecular aromatic denitrocyclization of 2-(2,4-dinitro-phenylsulfanyl)-benzoic acid amides. Efficient procedures for denitrocyclization in the presence of different bases are developed. Reduction of the nitro group in the obtained heterocycles resulted in formation of primary amines, which were transformed into amides by acylation with different carboxylic acids. The synthesized compounds have a great potential of bioactivity and are useful objects for biomedicinal screening. [source] Parameter identification of torsionally coupled shear buildings from earthquake response recordsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 11 2008Ganesh Hegde Abstract This paper presents an efficient procedure to determine the natural frequencies, modal damping ratios and mode shapes for torsionally coupled shear buildings using earthquake response records. It is shown that the responses recorded at the top and first floor levels are sufficient to identify the dominant modal properties of a multistoried torsionally coupled shear building with uniform mass and constant eccentricity even when the input excitation is not known. The procedure applies eigenrealization algorithm to generate the state-space model of the structure using the cross-correlations among the measured responses. The dynamic characteristics of the structure are determined from the state-space realization matrices. Since the mode shapes are obtained only at the instrumented floor (top and first floors) levels, a new mode shape interpolation technique has been proposed to estimate the mode shape coefficients at the remaining floor levels. The application of the procedure has been demonstrated through a numerical experiment on an eight-storied torsionally coupled shear building subjected to earthquake base excitation. The results show that the proposed parameter identification technique is capable of identifying dominant modal parameters and responses even with significant noise contamination of the response records. Copyright © 2008 John Wiley & Sons, Ltd. [source] Improved design of sliding mode control for civil structures with saturation problemEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 11 2004Sang-Hyun Lee Abstract A systematic and improved design procedure for sliding mode control (SMC) of seismically excited civil structures with saturation problem is provided in this paper. In order to restrict the control force to a certain level, a procedure for determining the upper limits of the control forces for single or multiple control units is proposed based on the design response spectrum of external loads. Further, an efficient procedure using the LQR method for determining sliding surfaces appropriate for different controller types is provided through the parametric evaluation of the dynamic characteristics of sliding surfaces in terms of SMC controller performance. Finally, a systematic design procedure for SMC required to achieve a given performance level is provided and its effectiveness is verified by applying it to multi-degree-of-freedom (MDOF) systems. Copyright © 2004 John Wiley & Sons, Ltd. [source] Monitoring of protein profiles for the optimization of recombinant fermentation processes using public domain databasesELECTROPHORESIS, Issue 1-2 2003Karin Dürrschmid Abstract The expression of human superoxide dismutase in fed-batch fermentation of E. coli HMS174(DE3)(pET3ahSOD) was studied as model system. Due to the frequently used strong T7 promoter system a high metabolic load is exerted, which triggers stress response mechanisms and finally leads to the differentiation of the host cell. As a consequence, host cell metabolism is partly shifted from growth to survival accompanied by significant alterations of the protein pattern. In terms of process optimization two-dimensional electrophoresis deserves as a powerful tool to monitor these changes on protein level. For the analysis of samples derived from different states of recombinant protein production wide-range Immobiline Dry Strips pH 3,10 were used. In order to establish an efficient procedure for accelerated process optimization and to avoid costly and time-consuming analysis like mass spectrometry (MS), a database approach for the identification of significant changes of the protein pattern was evaluated. On average, 935 spots per gel were detected, whereby 50 are presumably stress-relevant. Out of these, 24 proteins could be identified by using the SWISS-2DPAGE database (www.expasy.ch/ch2d/). The identified proteins are involved in regulatory networks, energy metabolism, purine and pyrimidine nucleotide synthesis and translation. By this database approach, significant fluctuations of individual proteins in relation to recombinant protein production could be identified. Seven proteins show strong alterations (>100%) directly after induction and can therefore be stated as reliable marker proteins for the assessment of stress response. For distinctive interpretation of this highly specific information, a bioinformatic and statistic tool would be essential in order to perceive the role and contribution of individual proteins in stress response. [source] Metal-Free Air Oxidation of Thiols in Recyclable Ionic Liquid: A Simple and Efficient Method for the Synthesis of DisulfidesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2010Devender Singh Abstract An efficient procedure for the oxidative coupling of alkyl, aryl and heteroaryl thiols with atmospheric oxygen is reported. The methodology utilizes BMIM-BF4 as a recyclable solvent and does not require support materials or metal salts. Symmetric disulfides are obtained in excellent yields. [source] Ilicic Acid as a Natural Quiron for the Efficient Preparation of Bioactive ,- and ,-EudesmolEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2009Alejandro F. Barrero Abstract An efficient procedure for the isolation of the sesquiterpene ilicic acid (3) on a multigram scale of extracts obtained from aerial parts of Inula viscosa (Asteraceae) was developed. Acid 3 is an appropriate starting material for short, enantiospecific syntheses of ,-eudesmol (1) and ,-eudesmol (2), natural products featuring significant antiangiogenic and anti-Alzheimer properties. Synthesis of 1 was achieved in six steps and the synthesis of 2 in seven, producing overall yields of 52 and 41,%, respectively.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Metal-Assisted Hybridization of Oligonucleotides, Evaluation of Circular 2,- O -Me RNA as Ligands for the TAR RNA TargetEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2003Laurence Zapata Abstract Two complementary oligonucleotides were conjugated with terpyridine ligands at their nearby 5,- and 3,-ends. Addition of a stoichiometric amount of a transition metal (Zn2+, Fe2+) resulted in a large increase in the melting temperature of the duplex. The conjugation of TPY to stem-loop oligomers provided an efficient procedure for the cyclisation of the oligomer after the addition of metal ions. Such a short stem-loop oligomer was designed to target the HIV-1 TAR RNA through loop,loop interactions. The addition of Zn2+ ions yielded a good ligand (Kd = 30 nM) for this RNA structural element. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Acoustic microfluidic chip technology to facilitate automation of phage display selectionFEBS JOURNAL, Issue 22 2008Jonas Persson Modern tools in proteomics require access to large arrays of specific binders for use in multiplex array formats, such as microarrays, to decipher complex biological processes. Combinatorial protein libraries offer a solution to the generation of collections of specific binders, but unit operations in the process to isolate binders from such libraries must be automatable to ensure an efficient procedure. In the present study, we show how a microfluidic concept that utilizes particle separation in an acoustic force field can be used to efficiently separate antigen-bound from unbound members of such libraries in a continuous flow format. Such a technology has the hallmarks for incorporation in a fully automated selection system for the isolation of specific binders. [source] Optimum design of stochastically excited non-linear dynamic systems without geometric constraintsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 11 2002M. M. Oblak Abstract This paper presents an efficient procedure for min,max dynamic response optimization of stochastically excited non-linear systems with multiple time-delayed inputs. This procedure employs a stochastic linearization technique to overcome system non-linearity and an auto-covariance analysis technique to represent the original stochastic mechanical model in a suitable form for optimization. Special attention is given to the sensitivity analysis, due to the complex nature of the problem. Therefore, exact expressions are obtained in a simple form for the evaluation of the required gradients, which greatly improve the stability and efficiency of the optimization algorithm. The numerical results and performance are presented by means of solving two min,max dynamic response optimization problems. Copyright © 2002 John Wiley & Sons, Ltd. [source] An efficient adaptive algorithm for edge detection based on the likelihood ratio testINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 4 2002A. De Santis Abstract The edge detection problem in blurred and noisy 2-D signals is dealt with. An adaptive signal processing algorithm is proposed which marks edge points according to an hypothesis test which compares the likelihoods of two models describing the local signal behaviour in the two cases of absence/presence of an edge. The two models are identified by a regularized least squares estimation algorithm, obtaining a numerically efficient procedure, quite robust with respect to additive noise and blurr perturbation. No global thresholding or data prefiltering is required. Copyright © 2002 John Wiley & Sons, Ltd. [source] Pyrazole Synthesis Using a Titanium-Catalyzed Multicomponent Coupling Reaction and Synthesis of WithasomnineADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Supriyo Majumder Abstract The titanium-catalyzed 3-component coupling of an alkyne, isonitrile, and amine can be used to generate tautomers of 1,3-diimines. These diimines produced in situ undergo cyclization with hydrazine and hydrazine derivatives in a one-pot procedure to provide pyrazoles. Seventeen examples of pyrazoles are provided using this one-pot, 4-component procedure from simple starting materials. The regioselectivity of the alkyne addition can be controlled in some cases with catalyst architecture, and regioselectivity of monosubsituted hydrazines to unsymmetrical 1,3-diimines is discussed. This multicomponent coupling strategy was applied to the synthesis of withasomnine in an efficient procedure, which gave the natural product in 24% overall yield from 4-pentyn-1-ol. [source] Alkylzinc-Mediated Addition of Alkynes to N -Tosylaldimines: Enantioselective Synthesis of (E)-(2-En-3-ynyl)-aminesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009Chao Yin Abstract An alkylzinc-mediated simple and efficient procedure for the catalytic enantioselective synthesis of N- tosyl-(E)-(2-en-3-ynyl)-amines has been developed. The method works well with various N -tosylaldimines and alkynes. [source] Reduction of Alkyl Halides by Triethylsilane Based on a Cationic Iridium Bis(phosphinite) Pincer Catalyst: Scope, Selectivity and MechanismADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Jian Yang Abstract A highly efficient procedure for the reduction of a broad range of alkyl halides by triethylsilane based on a cationic iridium bis(phosphinite) pincer catalyst has been discovered and developed. This reduction chemistry is chemoselective and has unique selectivities compared with conventional radical-based processes and the aluminum trichloride/triethylsilane (AlCl3/Et3SiH) and triphenylmethyl tetrakis[pentafluorophenyl]borate/triethylsilane {[Ph3C] [B(C6F5)4]/Et3SiH} systems. Reductions use three equivalents of triethylsilane relative to the halide and can be carried out with very low catalyst loadings and in a solvent-free manner, which may provide an environmentally attractive and safe alternative to many currently practiced methods for reduction of alkyl halides. Mechanistic studies reveal a unique catalytic cycle. The cationic iridium hydride 2,6-bis[di-(tert -butyl)phosphinyloxy)phenyl(hydrido)iridium, (POCOP)IrH+ {POCOP= 2,6-[OP(t- Bu)2]2C6H3} binds and activates the silane. This complex serves as a potent silylating reagent to generate silyl halonium ions, Et3SiXR+, which are reduced by the neutral iridium dihydride to yield alkane product and regenerate the cationic (POCOP)IrH+, thus closing the catalytic cycle. All key intermediates have been identified by in situ NMR monitoring and kinetic studies have been completed. An application of this reduction system to the catalytic hydrodehalogenation of a metal chloride complex is also described. [source] Midterm Results of Off-Pump Coronary Artery Bypass Surgery in 136 Patients: An Angiographic Control StudyJOURNAL OF CARDIAC SURGERY, Issue 1 2006Hakki Kazaz M.D. This study summarizes the midterm results of 136 off-pump bypass surgery patients. Methods: Between January 2000 and March 2002, out of 178 surgical myocardial revascularizations, 136 (76.4%) were off-pump bypass surgery. Complete revascularization was done and especially arterial grafts were used. All patients were followed clinically and with treadmill test for 2 years. Average control angiography was performed at the end of 2-year follow-up. Results: Of all the patients, 56.7% were male and the mean age of the patients was 63.6 ± 7.4 years. A total of 481 anastomoses were performed,136 (28.27%) to the left anterior descending artery (LAD), 135 (28.07%) to the circumflex coronary artery (Cx) branches, 102 (21.20%) to the right coronary artery (RCA), 108 (22.46%) to the D,. The mean graft number was 3.46. We used 96.6% of patients' left internal mammarian artery (LITA), 29.2% radial artery (RA), 4.4% right internal thoracic artery (RITA), and 100% saphenous vein. There were ischemic changes within 12 patients. All ischemic changes came back to normal within 4 and 18 hours, postoperatively. Mean extubation time was 5.36 ± 2.23 hours, mean stay in intensive care unit was 17.53 ± 3.15 hours, mean hospital stay was 5.03 ± 1.29 days. The LITA patency was 99.25%, RA patency was 97.84%, RITA patency was 100%, and saphenous vein patency was 91.79% with control angiography. Conclusion: Off-pump coronary artery bypass graft (CABG) is efficient procedure with lower index of mortality, morbidity, ICU stay, hospital stay, good wound healing, early socialization, and results in lower costs. [source] Solvent-free route to ,-enamino dichloromethyl ketones and application in the synthesis of novel 5-dichloromethyl-1H -pyrazolesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2009Marcos A. P. Martins An efficient procedure to prepare a series of five 4-amino-1,1-dichloro-3-penten-2-ones [CHCl2C(O)CHC(Me)NR1R2, where R1/R2 = H/Ph, H/Bn, H/CH2CH2OH, (CH2)4,(CH2)2O(CH2)2] from the solvent-free reaction of 1,1-dichloro-4-methoxy-3-penten-2-one with primary and secondary amines is reported. 1,1-Dichloro-4-methoxy-3-penten-2-one was reacted with hydrazine hydrochloride, phenylhydrazine hydrochloride and semicarbazide hydrochloride to obtain 5-dichloromethyl-3-methylpyrazoles. Aminoguanidine hydrochloride and 1,2-dimethylhydrazine dihydrochloride were also reacted with 1,1-dichloro-4-methoxy-3-penten-2-one to obtain 5-dichloromethyl-3-methylpyrazoline and 5-dichloromethyl-1,2,3-trimethyl pyrazolium chloride, respectively. All cyclocondensation reactions were performed in one-pot procedures. J. Heterocyclic Chem., (2009). [source] Synthesis of tritium labelled 3(R)-HETE and 3(R),18(R/S)-DiHETE through a common synthetic routeJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 1 2004Natalya V. Groza Abstract An efficient procedure for the synthesis of 3-hydroxyoxylipins labelled with tritium on all double bond positions is reported. The synthetic scheme involves a joint route for the formation of tetraacetylenic precursors followed by stereoselective reduction of the triple bonds either with hydrogen or tritium. The final tritiated products were obtained with specific activities ranging from 1.65 to 1.80 Ci/mmol. Copyright © 2003 John Wiley & Sons, Ltd. [source] Recipe determination and scheduling of gasoline blending operationsAICHE JOURNAL, Issue 2 2010Jie Li Abstract Gasoline is a major contributor to the profit of a refinery. Scheduling gasoline-blending operations is a critical and complex routine task involving tank allocation, component mixing, blending, product storage, and order delivery. Optimized schedules can maximize profit by avoiding ship demurrage, improving order delivery, minimizing quality give-aways, avoiding costly transitions and slop generation, and reducing inventory costs. However, the blending recipe and scheduling decisions make this problem a nonconvex mixed-integer nonlinear program (MINLP). In this article, we develop a slot-based MILP formulation for an integrated treatment of recipe, specifications, blending, and storage and incorporate many real-life features such as multipurpose product tanks, parallel nonidentical blenders, minimum run lengths, changeovers, piecewise constant profiles for blend component qualities and feed rates, etc. To ensure constant blending rates during a run, we develop a novel and efficient procedure that solves successive MILPs instead of a nonconvex MINLP. We use 14 examples with varying sizes and features to illustrate the superiority and effectiveness of our formulation and solution approach. The results show that our solution approach is superior to commercial solvers (BARON and DICOPT). © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Laser-assisted endoscopic third ventriculostomy for obstructive hydrocephalus: Technique and results in a series of 40 consecutive casesLASERS IN SURGERY AND MEDICINE, Issue 5 2004Bertrand C. Devaux MD Abstract Background and Objectives To report a case series of endoscopic third ventriculostomy (ETV) using laser in 40 consecutive patients with obstructive hydrocephalus. Study Design/Materials and Methods Under stereotactic and endoscopic guidance, multiple perforations in the ventricular floor using a 1.32 ,m neodymium,yttrium/aluminum/garnet (Nd,YAG) or a 0.805 ,m diode laser unit and removal of intervening coagulated tissue ensued with a 4,6 mm opening between third ventricle and basilar cisterns. Results The procedure could be completed in all cases. A transient complication occurred in five cases. In 39 patients (mean follow-up 28 months), 31 (79%) had a favorable outcome. Failure occurred in six patients, requiring permanent shunting leading to complete recovery, and two patients remained in a poor clinical status despite ETV. Conclusions Laser-assisted ETV is a safe and efficient procedure for the treatment of obstructive hydrocephalus. Laser is advantageous in cases of distorted anatomy and may reduce technical failures. Lasers Surg. Med. 34:368,378, 2004. © 2004 Wiley-Liss, Inc. [source] | |||||||||||||||||||