Search results for "ALK"

A Theoretical Study of the Relationship between the Electrophilicity ω Index and Hammett Constant σp in [3+2] Cycloaddition Reactions of Aryl Azide/A…

2016

The relationship between the electrophilicity ω index and the Hammett constant σp has been studied for the [2+3] cycloaddition reactions of a series of para-substituted phenyl azides towards para-substituted phenyl alkynes. The electrophilicity ω index—a reactivity density functional theory (DFT) descriptor evaluated at the ground state of the molecules—shows a good linear relationship with the Hammett substituent constants σp. The theoretical scale of reactivity correctly explains the electrophilic activation/deactivation effects promoted by electron-withdrawing and electron-releasing substituents in both azide and alkyne components.

Spontaneous growth of 2D coordination polymers on functionalized ferromagnetic surfaces

2018

2D coordination polymers grow spontaneously on reactive surfaces due to surface oxidation. The growth process is observed in real time.

GENE CLONING AND CHRACTERIZATION OF AN ALKANE HYDROXYLASE SYSTEM IN A LONG CHAIN N.ALKANE. DEGRADER GORDONIA SP.

2008

Treatment with electrical stimulation of sensory nerves improves motor function and disability status in persons with multiple sclerosis: A pilot stu…

2021

Abstract Declines in motor function are closely associated with decreases in sensory function in multiple sclerosis (MS). The purpose of our study was to assess the changes in motor function and disability status elicited by transcutaneous electrical nerve stimulation (TENS) to limb muscles of individuals with MS. Fifteen persons with MS and 11 age-matched healthy controls were evaluated before and after receiving 9 treatment sessions during which TENS was applied over the tibialis anterior and rectus femoris muscles of each leg, and over the median nerve and the thenar eminence of each hand. Each evaluation session involved completing two questionnaires (fatigue and walking limitations) an…

Earth Degassing in Tectonically Active Regions: New Evidences from Southern Italy and the Balkans

2022

Dvīņu pilsētu-Valkas un Valgas-pārrobežu sadarbība

2017

Kopš Šengenas zonas paplašināšanās Eiropas Savienības dalībvalstu robežu funkcijas ir mainījušās. Ir attīstījušās jaunas politiskās sadarbības formas starp nacionālajām robežām, un robežas kļuvušas atvērtākas. Maģistra darba mērķis ir noskaidrot un novērtēt līdzšinējo pārrobežu sadarbību starp dvīņu pilsētām uz Latvijas un Igaunijas robežas un atklāt aspektus, kas abām dvīņu pilsētām savā pārrobežu sadarbībā būtu jāuzlabo. Lai sasniegtu maģistra darba mērķi, tika izvirzīti vairāki uzdevumi, tostarp izpētīt pārrobežu sadarbību starp dvīņu pilsētām – Valku un Valgu, noskaidrot pārrobežu sadarbības labos piemērus un problēmas, kā arī izstrādāt priekšlikumus Valkas un Valgas pārrobežu sadarbība…

Geochemical constraints on basalt petrogenesis in the Strait of Sicily Rift Zone (Italy): Insights into the importance of short lengthscale mantle he…

2020

Igneous activity from the late Miocene to historic time (most recently 1891 CE) in the Strait of Sicily has created two volcanic islands (Pantelleria and Linosa) and several seamounts. These volcanoes are dominated by transitional (ol + hy-normative) to alkaline (ne-normative) basaltic lavas and scoriae; volcanic felsic rocks (peralkaline trachyte-rhyolite) crop out only on Pantelleria. Although most likely erupted through continental crust, basalts demonstrate no evidence of crustal contamination and are geochemically similar to oceanic island basalts (OIB). Despite their isotopic similarities, there are considerable compositional differences with respect to major and trace element geochem…

Trace element partitioning in lamproitic magmas—the Gaussberg olivine leucitite

2004

Abstract Partition coefficients for compatible and incompatible trace elements for use in modelling the origin and evolution of lamproitic and other potassic rocks are reported. These are based on values obtained by in situ determination using laser ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS) on mineral/glass pairs in examples of the Gaussberg olivine leucitite, a classic leucite lamproite. Leucite/melt partition coefficients for 32 elements show values above 1 only for Cs and Rb, whereas values for Ni, Ga and Co are 0.4–0.1. DLc/Lq for most other elements are in the range 0.07–0.0005, and delineate a gently sloping pattern to lower values for elements gene…

Mobility and fluxes of major, minor and trace metals during basalt weathering and groundwater transport at Mt. Etna volcano (Sicily)

2000

Abstract The concentrations and fluxes of major, minor and trace metals were determined in 53 samples of groundwaters from around Mt Etna, in order to evaluate the conditions and extent of alkali basalt weathering by waters enriched in magma-derived CO 2 and the contribution of aqueous transport to the overall metal discharge of the volcano. We show that gaseous input of magmatic volatile metals into the Etnean aquifer is small or negligible, being limited by cooling of the rising fluids. Basalt leaching by weakly acidic, CO 2 -charged water is the overwhelming source of metals and appears to be more extensive in two sectors of the S-SW (Paterno) and E (Zafferana) volcano flanks, where out …

Geochemical mapping of magmatic gas–water–rock interactions in the aquifer of Mount Etna volcano

2001

Abstract Systematic analysis of major and minor elements in groundwaters from springs and wells on the slopes of Mt. Etna in 1995–1998 provides a detailed geochemical mapping of the aquifer of the volcano and of the interactions between magmatic gas, water bodies and their host rocks. Strong spatial correlations between the largest anomalies in pCO2 (pH and alkalinity) K, Rb, Mg, Ca and Sr suggest a dominating control by magmatic gas (CO2) and consequent basalt leaching by acidified waters of the shallow (meteoric) Etnean aquifer. Most groundwaters displaying this magmatic-type interaction discharge within active faulted zones on the S–SW and E lower flanks of the volcanic pile, but also in…