Search results for "upe"

A Green Look at the Aldol Reaction

2005

Aldol reactions have been and are widely applied for the preparation of β-hydroxy aldehydes, β-hydroxy ketones or α,β-unsaturated aldehydes or ketones through addition or addition-elimination reactions of aldehydes and ketones. The study of the aldol reaction from the point of view of its greenness must have in mind first of all that a general synthetic method must be based on complete and efficient conversions of well defined selectivity and that greenness is more a term for comparison than an absolute kind of qualification. This comparison, when referred to the aldol reaction, applies here to the diverse modifications of the reaction. Thus, the original poorly selective, but highly atom e…

ChemInform Abstract: Non-Conventional Methods and Media for the Activation and Manipulation of Carbon Nanoforms

2014

Very often, chemical transformations require tedious and long procedures, which, sometimes, can be avoided using alternative methods and media. New protocols, enabling us to save time and solvents, allow us also to explore new reaction profiles. This Tutorial Review focuses on the physical and chemical behavior of carbon nanoforms, CNFs (fullerenes, nanotubes, nanohorns, graphene, etc.) when non-conventional methods and techniques, such as microwave irradiation, mechano-chemistry or highly ionizing radiations are employed. In addition, the reactivity of CNFs in non-conventional media such as water, fluorinated solvents, supercritical fluids, or ionic liquids is also discussed.

Amatas upes hidroloģiskā režīma ilgtermiņa un sezonālās izmaiņas

2017

Darba mērķis ir izvērtēt Amatas upes hidroloģiskā režīma sezonālās un ilgtermiņa izmaiņas mainīga klimata apstākļos. Darbā raksturots Gaujas baseina upju hidroloģiskais režīms un to ietekmējošie faktori, aplūkoti hidroloģiskā režīma pētījumi Latvijā un Baltijā. Veikts Amatas upes baseina fizioģeogrāfiskais raksturojums. Analizēti rezultāti par Amatas upes hidroloģiskā režīma raksturojošo parametru (caurplūdums, temperatūra, ledus izveidošanās un uzlūšanas datumi, ledstāves ilgums) sezonālajām un ilgtermiņa izmaiņām un to savstarpējo korelāciju ar meteoroloģiskajiem parametriem (gaisa temperatūra un atmosfēras nokrišņi) laika periodā no 1921.-2015. gadam. Noteces režīms raksturots, analizējo…

Triterpene saponins from the roots ofAmpelozizyphus amazonicus

1992

A new triterpene saponin was isolated from the roots of Ampelozizyphus amazonicus together with the known 3-O-beta-D-glucopyranosyl-20-O-alpha-L-rhamnopyranosyljujubogenin and the known triterpenes melaleucic acid, 3 beta,27 alpha-dihydroxylup-20(29)-en-28 beta-oic acid, betulinic acid, betulin, lupeol. The structure of this saponin was elucidated as 3-O-[beta-D-glucopyranosyl(1----2)alpha-L-arabinopyranosyl]- 20-O-alpha-L-rhamnopyranosyljujubogenin by spectral analysis and chemical transformations.

Amyloid-Like Superstructures: mechanisms of formation and morphologies

2014

Concanavalin A fibrils formation from Coagulation of Long-lived" Crinkled" Intermediates

2013

Sympathetic blocks for visceral cancer pain management: A systematic review and EAPC recommendations.

2015

The neurolytic blocks of sympathetic pathways, including celiac plexus block (CPB) and superior hypogastric plexus block (SHPB) , have been used for years. The aim of this review was to assess the evidence to support the performance of sympathetic blocks in cancer patients with abdominal visceral pain. Only comparison studies were included. All data from the eligible trials were analyzed using the GRADE system. Twenty-seven controlled studies were considered. CPB, regardless of the technique used, improved analgesia and/or decrease opioid consumption, and decreased opioid-induced adverse effects in comparison with a conventional analgesic treatment. In one study patients treated with superi…

Contribution de l’analyse de scène auditive à l’analyse de la performance

2017

Disponible sur : http://euromac2017.unistra.fr/wp-content/uploads/2017/05/Ext.-Lalitte-Philippe.pdf. Intervention donnée en Session 13C : Analyser la performance aujourd'hui : enjeux et perspectives; International audience; L’analyse de la performance de musiques savantes écrites des XXe–XXIe siècles pose des problèmes méthodologiques spécifiques à ce répertoire (Lalitte, 2015). Plus que dans un autre répertoire, l’interprète a un rôle particulièrement important pour transmettre à l’auditeur une image auditive (McAdams, 1984) la plus cohérente possible d’œuvres fréquemment qualifiées de perceptivement complexes. Cette constatation est particulièrement cruciale dans la musique polyphonique o…

Localisation optimale des établissements scolaires

1973

Sub- and supercritical fluid extraction of trichloropyridinol from soil prior to immunoassay

1997

A comparative study on the extraction of TCP (3,5,6-trichloro-2-pyridinol, a metabolite of chlorpyrifos) from soil with CO2 and H2O is reported. The polarity of the analyte requires the presence of both a cosolvent (methanol) and an ion-pair reagent [(1R)-(-)-10-camphorsulfonic acid ammonium salt] for 95% extraction in 30 min when supercritical CO2 at 40 degrees C and 383 bar is used as extractant. Subcritical water (250 degrees C and 200 bar) enables complete extraction within 15 min without additives. Quantitation of the target analyte is performed by specific immunoassay using a non-commercial monoclonal antibody which provides a linear determination range between 0.005 and 5 micrograms/…