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Efficient Protocol (efficient + protocol)
Selected AbstractsLewis Acid-Mediated Selective Cycloadditions of Vinylidenecyclopropanes with Aromatic Aldehydes: An Efficient Protocol for the Synthesis of Benzo[c]fluorene, Furan and Furo[2,3- b]furan DerivativesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Chenliang Su Abstract Three kinds of Lewis acid-mediated reactions of vinylidenecyclopropanes and aromatic aldehydes are disclosed in this paper, providing an efficient and selective synthesis of a variety of functionalized benzo[c]fluorene, furan and furo[2,3- b]furan derivatives. [source] An Efficient Protocol for NMR-Spectroscopy-Based Structure Determination of Protein Complexes in Solution,ANGEWANDTE CHEMIE, Issue 11 2010Bernd Simon Dr. Puzzle-Arbeit: Eine effiziente, allgemein anwendbare Methode zur Bestimmung der Struktur von Proteinkomplexen und Mehrdomänenproteinen in Lösung mithilfe der NMR-Spektroskopie wird vorgestellt. Ausgehend von den bekannten hochaufgelösten Strukturen einzelner Domänen oder Untereinheiten wird die Domänenanordnung des Gesamtsystems aus NMR-Daten abgeleitet, die auch für hochmolekulare Komplexe zugänglich sind. [source] ChemInform Abstract: An Efficient Protocol for Alcohol Protection under Solvent- and Catalyst-Free Conditions.CHEMINFORM, Issue 16 2010Ch. Bhujanga Rao Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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: Tin(II) Chloride Dihydrate Catalyzed Groebke Condensation: An Efficient Protocol for the Synthesis of 3-Aminoimidazo[1,2-a]pyridines.CHEMINFORM, Issue 27 2009Ahmad Shaabani 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 Protocol for Multicomponent Stereoselective Synthesis of 3-Amino-2(1H)-pyridinones Using CeCl3×7H2O/NaI as a Reaction Promoter.CHEMINFORM, Issue 4 2009Lal Dhar S. Yadav 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 Convenient and Efficient Protocol for the Synthesis of Symmetrical N,N,-Alkylidine Bisamides by Sulfamic Acid under Solvent-Free Conditions.CHEMINFORM, Issue 25 2008Nagarajan Panneer Selvam 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] Zirconium(IV) Chloride Catalyzed New and Efficient Protocol for the Selective Cleavage of p-Methoxybenzyl Ethers.CHEMINFORM, Issue 40 2003Gangavaram V. Madhava Sharma Abstract For Abstract see ChemInform Abstract in Full Text. [source] Efficient and sensitive method of DNA silver staining in polyacrylamide gelsELECTROPHORESIS, Issue 1 2005Lujiang Qu Abstract DNA silver staining is widely used to detect DNA fragment in polyacrylamide gel with high sensitivity. Conventional procedures of the silver staining involve several steps, which take about 40 min to 2 h in total. To improve the efficiency of DNA silver staining, a more efficient protocol is developed in this study. The procedure comprises only four steps including impregnating, rinsing, developing, and stopping, and could be completed within 20 min. Nitric acid and ethanol in the silver-impregnation step of the new procedure eliminates the need for prior treatment of gels with a fixing solution and following rinse prior to impregnation with silver. The procedure has high sensitivity and long storage lifetime. The minimum detectable mass of DNA is 0.44 and 3.5 ng in denaturing and nondenaturing polyacrylamide gel, respectively. [source] A Metathesis Approach for the Preparation of Polyhydroxylated Compounds as Head Groups in Surfactant SynthesisEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2006Kristina Neimert-Andersson Abstract Starting from methyl-,- D -glucopyranoside, an efficient protocol for the preparation of polyhydroxylated surfactant head-groups is demonstrated and applied in the synthesis of a typical surfactant. The key transformation is a metathesis reaction between two monosaccharide residues to afford an octahydroxydecen. The importance of a strategic protecting-group constellation for a successful metathesis reaction is also investigated. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Optimization of culture conditions for plant regeneration of Panicum spp. through somatic embryogenesisGRASSLAND SCIENCE, Issue 1 2010Mi-Suk Seo Abstract We developed a rapid and efficient shoot regeneration system for Panicum spp. by adjusting the regeneration medium and studying the responses of different genotypes and the influence of explant types (mature seed, immature embryo and shoot apex). We used Panicum meyerianum (Nees) and Panicum longijubatum (Stapf) which were shown to perform well, to select the optimal medium for shoot regeneration. The highest frequency of shoot regeneration was obtained on Murashige and Skoog medium supplemented with 30 g L,1 maltose and 1 mg L,1 N-phenyl-N,-[(1,2,3-thidiazol-5-yl) urea]. The callus formed green spots after 1 week of culture and showed primary green shoots after 2 weeks. In this system, the calli derived from mature seed of nine Panicum genotypes showed large variation in shoot regeneration ability: from 0 to 69.9% in the frequency of shoot formation and from 0 to 8.4 in the number of shoots per callus. Guineagrass (Panicum maximum Jacq.) showed no ability and switchgrass (Panicum virgatum L.) showed low ability to regenerate from mature seed-derived calli; however, both were able to be regenerated from immature embryos and calli derived from shoot apices. We developed an efficient protocol for high shoot regeneration of various Panicum genotypes which provides a foundation for efficient tissue culture and genetic improvement of Panicum. [source] An Improved Protocol for the Synthesis of Quinoline-2,3-dicarboxylates under Neutral Conditions via Biomimetic ApproachHELVETICA CHIMICA ACTA, Issue 2 2010Bandaru Madhav Abstract A mild and efficient protocol for synthesis of quinoline derivatives in aqueous medium under neutral conditions is described. The reaction proceeded smoothly in H2O catalyzed by supramolecular catalyst , -CD. By this protocol, various quinoline derivatives were synthesized in excellent yields. [source] Preparation of Arylphosphonates by Palladium(0)-Catalyzed Cross-Coupling in the Presence of Acetate Additives: Synthetic and Mechanistic StudiesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Marcin Kalek Abstract An efficient protocol for the synthesis of arylphosphonate diesters via a palladium-catalyzed cross-coupling of H-phosphonate diesters with aryl electrophiles, promoted by acetate ions, was developed. A significant shortening of the cross-coupling time in the presence of the added acetate ions was achieved for bidentate and monodentate supporting ligands, and for different aryl electrophiles (iodo, bromo and triflate derivatives). The reaction conditions were optimized in terms of amount of the catalyst, supporting ligands, and source of the acetate ion used. Various arylphosphonates, including those of potential biological significance, were synthesized using this newly developed protocol. Some mechanistic aspects of the investigated reactions are also discussed. [source] A New Approach to Pyrrolocoumarin Derivatives by Palladium-Catalyzed Reactions: Expedient Construction of Polycyclic Lamellarin ScaffoldADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Lei Chen Abstract A new and efficient protocol for straightforward synthesis of chromeno[3,4- b]pyrrol-4(3H)-one derivatives by palladium-catalyzed sequential coupling/cyclization reactions has been developed. The key strategy relies on creation of pyrrole ring through palladium-catalyzed intramolecular hydroamination of related acetylenic aminocoumarins. The synthetic utility of the obtained chromeno[3,4- b]pyrrol-4(3H)-one product has been demonstrated by the expedient synthesis of polycyclic lamellarin scaffold in four steps. It provides a new entry to synthesis of potentially valuable lamellarin analogues. [source] Improved Suzuki,Miyaura Reactions of Aryldiazonium Salts with Boronic Acids by Tuning Palladium on Charcoal Catalyst PropertiesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2009François-Xavier Felpin Abstract An improved Suzuki,Miyaura cross-coupling reaction of aryldiazonium tetrafluoroborates with boronic acids catalyzed by a highly active palladium catalyst supported on charcoal is described as an extremely practical and efficient protocol. A properties-activity study of various catalysts clearly established that the optimal catalytic activity was obtained with palladium nanoparticles having a low oxidation degree and uniformly dispersed on the charcoal. The optimized reaction conditions allow the cross-coupling to proceed at room temperature without any base and ligand in technical grade methanol. Although the catalyst could not be recycled, the low palladium contamination of the solvent and product after a simple filtration of the palladium on charcoal (Pd/C) renders the present protocol competitive and safer for the environment compared to more conventional homogeneous conditions. We have highlighted the efficiency of this novel protocol by a short synthesis of the fungicide Boscalid®. [source] Highly Regio- and Stereoselective Iodohydroxylation of Non- Heteroatom-Substituted Allenes: An Efficient Synthesis of 4-[3,-Hydroxy-2,-iodoalk-1,(Z)-enyl]-2(5H)-furanone DerivativesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2007Zhenhua Gu Abstract An efficient protocol for the highly regio- and stereoselective synthesis of 4-(3,-hydroxy-2,-iodoalk-1,(Z)-enyl)furan-2(5H)-one derivatives via selective iodohydroxylation of non-heteroatom-substituted allenes, i.e., 4-allenyl-2(5H)furanones, has been developed. The regio- and stereoselectivity of this reaction may be controlled by the electronic and steric effects of the furanone ring. [source] Monitoring Regional Riparian Forest Cover Change Using Stratified Sampling and Multiresolution Imagery,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 2 2010Peter R. Claggett Claggett, Peter R., Judy A. Okay, and Stephen V. Stehman, 2010. Monitoring Regional Riparian Forest Cover Change Using Stratified Sampling and Multiresolution Imagery. Journal of the American Water Resources Association (JAWRA) 46(2):334-343. DOI: 10.1111/j.1752-1688.2010.00424.x Abstract:, The Chesapeake Bay watershed encompasses 165,760 km2 of land area with 464,098 km of rivers and streams. As part of the Chesapeake Bay restoration effort, state and federal partners have committed to restoring 26,000 miles (41,843 km) of riparian forest buffers. Monitoring trends in riparian forest buffers over large areas is necessary to evaluate the efficacy of these restoration efforts. A sampling approach for estimating change in riparian forest cover from 1993/1994 to 2005 was developed and implemented in Anne Arundel County, Maryland, to exemplify a method that could be applied throughout the Bay watershed. All stream reaches in the county were stratified using forest cover change derived from Landsat imagery. A stratified random sample of 219 reaches was selected and forest cover change within the riparian buffer of each sampled reach was interpreted from high-resolution aerial photography. The estimated footprint of gross change in riparian forest cover (i.e., the sum of gross gain and gross loss) for the county was 1.83% (SE = 0.22%). Stratified sampling taking advantage of a priori knowledge of locations of change proved to be a practical and efficient protocol for estimating riparian forest buffer change at the county scale and the protocol would readily extend to much broader scale monitoring. [source] Optimization of primary culture condition for mesenchymal stem cells derived from umbilical cord blood with factorial designBIOTECHNOLOGY PROGRESS, Issue 2 2009Xiubo Fan Abstract Mesenchymal stem cells (MSCs) can not only support the expansion of hematopoietic stem cells in vitro, but also alleviate complications and accelerate recovery of hematopoiesis during hematopoietic stem cell transplantation. However, it proved challenging to culture MSCs from umbilical cord blood (UCB) with a success rate of 20,30%. Many cell culture parameters contribute to this outcome and hence optimization of culture conditions is critical to increase the probability of success. In this work, fractional factorial design was applied to study the effect of cell inoculated density, combination and dose of cytokines, and presence of serum and stromal cells. The cultured UCB-MSC-like cells were characterized by flow cytometry and their multilineage differentiation potentials were tested. The optimal protocol was identified achieving above 90% successful outcome: 2 × 106 cells/mL mononuclear cells inoculated in Iscove's modified Dulbecco's medium supplied with 10% FBS, 15 ng/mL IL-3, and 5 ng/mL Granulocyte-macrophage colony-stimulating factor (GM-CSF). Moreover, the UCB-MSC-like cells expressed MSC surface markers of CD13, CD29, CD105, CD166, and CD44 positively, and CD34, CD45, and human leukocyte antigens-DR (HLA-DR) negatively. Meanwhile, these cells could differentiate into osteoblasts, chondrocytes, and adipocytes similarly to MSCs derived from bone marrow. In conclusion, we have developed an efficient protocol for the primary culture of UCB-MSCs by adding suitable cytokines into the culture system. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] ChemInform Abstract: In situ Formation of N,O-Bidentate Ligand via the Hydrogen Bond for Highly Efficient Suzuki Reaction of Aryl Chlorides.CHEMINFORM, Issue 35 2010Weibo Yang Abstract An efficient protocol is elaborated for the phosphine-free Suzuki reaction mediated by hydrogen bond complexes between EtOH and DMA. [source] ChemInform Abstract: Cross Coupling in Water: Suzuki,Miyaura Vinylation and Difluorovinylation of Arylboronic Acids.CHEMINFORM, Issue 33 2010Jan Pschierer Abstract A general and efficient protocol for the Suzuki,Miyaura vinylation of arylboronic acids in aqueous media is developed utilizing a catalyst system consisting of Na2PdCl4 and the commercially available, water-soluble fluorenylphosphine ligand cataCXium F sulf. [source] ChemInform Abstract: Efficient Synthesis of Azaspirodienones by Microwave-Assisted Radical Spirocyclization of Xanthate-Containing Ugi Adducts.CHEMINFORM, Issue 33 2010Rocio Gamez-Montano Abstract By use of a sequential combination of Ugi reaction and microwave-promoted radical spirocyclization, an efficient protocol for the preparation of five- and six-membered spirolactams is developed. [source] Organocatalytic Enantioselective Synthesis of Highly Functionalized Polysubstituted PyrrolidinesCHEMISTRY - A EUROPEAN JOURNAL, Issue 30 2008Nerea Ruiz Abstract The organocatalytic conjugate addition of different aldehydes to ,-nitroacrolein dimethyl acetal, generating the corresponding highly functionalized nitroaldehydes in high yields and with high stereoselectivities, has been studied in detail. These transformations have been achieved by using both readily available starting materials in a 1:1 ratio as well as commercially available catalysts at a 10,mol,% catalyst loading. Furthermore, a very short and efficient protocol has been devised for the preparation of highly enantioenriched pyrrolidines containing two or three contiguous stereocenters starting from the obtained Michael adducts. 3,4-Disubstituted pyrrolidines have been obtained in a single step by Zn-mediated chemoselective reduction of the nitro group followed by intramolecular reductive amination, and trisubstituted homoproline derivatives have been prepared by means of an olefination reaction and a cascade process involving chemoselective reduction of the nitro group followed by a fully diastereoselective intramolecular aza- Michael reaction. Se ha estudiado detalladamente la reacción de adición conjugada organocatalítica enantioselectiva de distintos aldehídos con el dimetil acetal de ,-nitroacroleina, obteniéndose los aductos correspondientes con excelente rendimiento y diastereo- y enantioselectividad. Esta transformación se lleva a cabo empleando cantidades equimolares de aldehído y nitroalqueno así como aminas secundarias quirales disponibles comercialmente como catalizadores en cantidad de 10,% molar. Además, se ha puesto a punto un protocolo sencillo y eficaz para la síntesis de pirrolidinas enantioenriquecidas conteniendo dos o tres estereocentros contíguos partiendo de los aductos Michael obtenidos. Así, se han preparado pirrolidinas 3,4-disustituidas desde sus precursores nitroaldehídicos a través de un proceso en cascada consistente en la reducción quemoselectiva del grupo nitro seguido de una reacción de aminación reductora intramolecular. Del mismo modo, partiendo de los mismos precursores, se han preparado derivados de homoprolina con tres centros estereogénicos mediante una reacción de Wittig seguida de un proceso en cascada de reducción/reacción aza-Michael intramolecular, cursando esta última con total diastereoselectividad. [source] A Gold(I)-Catalyzed Intramolecular Reaction of Propargylic/Homopropargylic Alcohols with OxiraneCHEMISTRY - A EUROPEAN JOURNAL, Issue 23 2008Lun-Zhi Dai Abstract The gold(I)-catalyzed cycloisomerization of epoxy alkynes in the presence of a nucleophile is an efficient protocol to provide ketal skeletons with high stereoselectivity. An intramolecular reaction of propargylic/homopropargylic alcohols with oxirane to produce ketal/spiroketals in moderate yields under mild conditions has been reported. Moreover, the mechanism of this kind of reaction has been discussed on the basis of a series of control and 18O tracer experiments. [source] Using ants as bioindicators in land management: simplifying assessment of ant community responsesJOURNAL OF APPLIED ECOLOGY, Issue 1 2002Alan N. Andersen Summary 1The indicator qualities of terrestrial invertebrates are widely recognized in the context of detecting ecological change associated with human land-use. However, the use of terrestrial invertebrates as bioindicators remains more a topic of scientific discourse than a part of land-management practice, largely because their inordinate numbers, taxonomic challenges and general unfamiliarity make invertebrates too intimidating for most land-management agencies. Terrestrial invertebrates will not be widely adopted as bioindicators in land management until simple and efficient protocols have been developed that meet the needs of land managers. 2In Australia, ants are one group of terrestrial insects that has been commonly adopted as bioindicators in land management, and this study examined the reliability of a simplified ant assessment protocol designed to be within the capacity of a wide range of land managers. 3Ants had previously been surveyed intensively as part of a comprehensive assessment of biodiversity responses to SO2 emissions from a large copper and lead smelter at Mt Isa in the Australian semi-arid tropics. This intensive ant survey yielded 174 species from 24 genera, and revealed seven key patterns of ant community structure and composition in relation to habitat and SO2 levels. 4We tested the extent to which a greatly simplified ant assessment was able to reproduce these results. Our simplified assessment was based on ant ,bycatch' from bucket-sized (20-litre) pitfall traps used to sample vertebrates as part of the broader biodiversity survey. We also greatly simplified the sorting of ant morphospecies by considering only large (using a threshold of 4 mm) species, and we reduced sorting time by considering only the presence or absence of species at each site. In this manner, the inclusion of ants in the assessment process required less than 10% of the effort demanded by the intensive ant survey. 5Our simplified protocol reproduced virtually all the key findings of the intensive survey. This puts effective ant monitoring within the capacity of a wide range of land managers. [source] Strategies for Directing the Differentiation of Stem Cells Into the Osteogenic Lineage In Vitro,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2004Boon Chin Heng Abstract A major area in regenerative medicine is the application of stem cells in bone reconstruction and bone tissue engineering. This will require well-defined and efficient protocols for directing the differentiation of stem cells into the osteogenic lineage, followed by their selective purification and proliferation in vitro. The development of such protocols would reduce the likelihood of spontaneous differentiation of stem cells into divergent lineages on transplantation, as well as reduce the risk of teratoma formation in the case of embryonic stem cells. Additionally, such protocols could provide useful in vitro models for studying osteogenesis and bone development, and facilitate the genetic manipulation of stem cells for therapeutic applications. The development of pharmokinetic and cytotoxicity/genotoxicity screening tests for bone-related biomaterials and drugs could also use protocols developed for the osteogenic differentiation of stem cells. This review critically examines the various strategies that could be used to direct the differentiation of stem cells into the osteogenic lineage in vitro. [source] Molecular pathological approaches to human tumor immunologyPATHOLOGY INTERNATIONAL, Issue 4 2009Noriyuki Sato Research on human tumor immunology has greatly advanced in the past two decades. Many immunogenic tumor antigens have been identified, and some of these antigens entered in clinical trials. Consequently, it has been shown that these antigens can inhibit tumor growth in patients to some extent, indicating that they act as potent immunogenic therapeutic vaccines in cancer patients with malignancies originating from various tissues. These patients had antigen-specific cytotoxic T-lymphocyte (CTL) responses when assessed on tetramer, enzyme-linked immunospot (ELISPOT), T-cell clonotype and CTL induction efficiency. Thus, it has become clear that human tumor vaccines can evoke clinical and immunological anti-tumor responses in patients. The tumor regression effects of tumor vaccines, however, are generally low, and it is obvious that current vaccination protocols are generally too weak to provide substantial and satisfactory clinical benefits. This means that other drastic and more potent clinical and immunological protocols are required in cancer immunotherapy. To find such efficient protocols the basic immunological and biological properties of cancers must be investigated. In the present review the identification of human tumor antigens recognized on CTL and the clinical trials are introduced. Next, the most recent analysis of human cancer-initiating cell (cancer stem cell)-associated antigens is described. These antigens might be able to act as ,universal, general and fundamental' tumor antigens. Also present is the authors' recent study for increasing cross-presentation efficiency in dendritic cells and subsequent enhancement of human leukocyte antigen (HLA)-class I-restricted peptide antigenicity by using HSP90 and ORP150 molecular chaperones that act as endogenous Toll-like receptor ligands. In addition to the aforementioned manipulation of the positive loop of tumor immunity, it is necessary to regulate and intervene in the negative loop. In particular, the potential of the expression of HLA class I molecule regulation by epigenetic mechanisms will be discussed. Finally, the type of basic and clinical tumor immunology research highly required currently, and in the very near future, are described. [source] | |||||||||||||||||||||||||||||||