Search results for "feature"

Methacrylate monolithic columns functionalized with epinephrine for capillary electrochromatography applications.

2013

Epinephrine-bonded polymeric monoliths for capillary electrochromatography (CEC) were developed by nucleophilic substitution reaction of epoxide groups of poly(glycidyl-methacrylate-co-ethylenedimethacrylate) (poly(GMA-co-EDMA)) monoliths using epinephrine as nucleophilic reagent. The ring opening reaction under dynamic conditions was optimized. Successful chemical modification of the monolith surface was ascertained by in situ Raman spectroscopy characterization. In addition, the amount of epinephrine groups that was bound to the monolith surface was evaluated by oxidation of the catechol groups with Ce(IV), followed by spectrophotometric measurement of unreacted Ce(IV). About 9% of all th…

Cover Feature: Mannose-Decorated Multicomponent Supramolecular Polymers Trigger Effective Uptake into Antigen-Presenting Cells (ChemBioChem 9/2018)

2018

Determination of volatile fatty acids in the hot springs of Vulcano, Aeolian Islands, Italy

1998

Abstract Samples of relatively acid hydrothermal fluids were collected in the spring of 1996 from seeps, springs, and wells on the Island of Vulcano in the southern Tyrrhenian Sea and analyzed for volatile fatty acids 1 using liquid chromatography. Concentrations of VFAs in the seeps were in the range 65–140 ppb formic, 133–184 ppb acetic, and

Seasonal and spatial heterogeneity in the water chemistry of two sewage-affected saline shallow lakes from central Spain

2003

The seasonal features of the water chemistry in the saline shallow lakes Laguna de Manjavacas and Laguna del Pueblo (Castilla – La Mancha, Central Spain) were studied during 1990–1991 and in 1997. These lakes were both affected by sewage inputs driving them to a high trophic status. However, whereas sewage inputs entered Laguna del Pueblo directly, wastewater reached Laguna de Manjavacas after running for 8 km through a small riverbed, where natural processes caused partial mineralisation of organic matter. Moreover, water quality was further improved before entering the main water body of Laguna de Manjavacas, since water crossed through a wetland and high amounts of organic matter and ino…

Zur Ökologie Abwasserbelasteter Altrheine

1977

The backwaters of the Upper Rhine can be divided into two types, namely the Sondernheim type and the Leimersheim type. The first one obtains its water mainly from small tributaries of the Rhine, the latter one by the Rhine itself. Both of them are polluted to nearly the same extent by organic matter. In the Sondernheim type biological decomposition starts intensively. It leads to mass-production of a few animal species in the upper, to less production of a large number of animal species in the lower part of its flow. In the Leimersheim type neither biological decomposition, nor mass-production nor a high species-diversity are to be observed. The possible causes of this difference are under …

Cementing agents involved in the macro- and microaggregation of a Mediterranean shrubland soil under laboratory heating

2014

The heating effect on aggregation and cementing agents of a Mediterranean soil was studied in two fractions (macro- and microaggregates) in different environments: under Quercus coccifera soil (UQ), under Rosmarinus officinalis soil (UR) and between plants or bare soil (BS). Samples were heated under laboratory conditions at different temperatures (220, 380, 500, 750 and 1000. °C) to establish their effects on the studied soil properties by comparison with unheated control samples (25. °C). Increasing temperature treatments caused significant changes in most soil variables. In both soil fractions, the presence of vegetation contributed to increase of the soil organic matter (SOM) content, w…

"Dormant" secondary metal-alkyl complexes are not omnipresent.

2006

This theoretical study was inspired by the perpetual debate over the so-called “dormancy” of the active sites in propylene polymerization, i.e., a drop in their activity after a regioerror (2,1-insertion), which was reported to occur in many (although not all) catalytic systems. To explore the range of possible situations, we have selected two homogeneous systems of fundamentally different structure: an octahedral system of C 2 symmetry with a tetradentate O N N O ligand and a bridged indenyl catalyst. This choice was not accidental; it is in these two systems where the experimentalists cannot reach a consensus about dormancy. Our density-functional theory calculations explain why in certa…

The relationship between food availability and growth in Mytilus galloprovincialis in the open sea (southern Mediterranean)

1998

Abstract With the aim of gathering information about the possibility of culturing mussels ( Mytilus galloprovincialis ) in a south Mediterranean oligotrophic area, different lots of mussels were placed in culture at depths of −5 m and −15 m and their growth monitored on a monthly basis. Temperature and salinity were measured in situ and water samples were collected at different depths each month. Total suspended matter (TSM) and its inorganic (ISM) and organic (OSM) fractions were analysed by gravimetry and loss on ignition. Photosynthetic pigments (chlorophyll- a and phaeopigments), particulate organic carbon (POC) and nitrogen (PON), particulate carbohydrate (CHO), protein (PRT) and lipid…

Natural organic matter export from boreal catchments (the Salaca River basin, Latvia) and its influencing factors

2012

A noteworthy increase in the organic matter concentration and export, as well as water colour, in the catchments of the Salaca River has been observed during the last decades. This study investigates factors behind this increase: the impact of climate, land use and human loading changes on the concentrations and export of the organic matter in the Salaca River/Lake Burtnieks catchments. Proportion of wetlands in the river basin, type of land use, and runoff regime can be considered as the main factors influencing the organic carbon loadings. Despite a steady overall tendency of increase, considerable oscillations of organic matter loadings influenced by the changes in the river discharge re…

Carbon decomposition of the topsoils and soil fractions under forest and pasture in the western Brazilian Amazon basin, Rondonia

2000

The topsoils of two sites, comprising natural forest and 4- and 20-year-old pastures, respectively, were selected in Rondonia to evaluate the changes of soil organic matter due to pasture establishment. These changes were evaluated by measuring the proportions of the C and N associated with clay and silt fractions, and by the C decomposition (CD) rate of the whole topsoils and their size fractions. The topsoils studied had large proportions of C and N associated with fine fractions, especially with clay fractions. The CD rate of the silt fractions was higher than that of the clay fractions under the two forest topsoils and under the 20-year-old pasture. The CD rate of the silt fractions und…