Search results for "feature"
showing 10 items of 4091 documents
Sensitive determination of parabens in human urine and serum using methacrylate monoliths and reversed-phase capillary liquid chromatography-mass spe…
2014
A method for the determination of parabens in human urine and serum by capillary liquid chromatography (cLC) with UV-Vis and mass spectrometry (MS) detection using methacrylate ester-based monolithic columns has been developed. The influence of composition of polymerization mixture was studied. The optimum monolith was obtained with butyl methacrylate monomer at 60/40% (wt/wt) butyl methacrylate/ethylene dimethacrylate ratio and 50wt% porogens (composed of 36wt% of 1,4-butanediol, 54wt% 1-propanol and 10wt% water). Baseline resolution of analytes was achieved through a mobile phase of acetonitrile/water in gradient elution mode. Additionally, dispersive liquid-liquid microextraction (DLLME)…
Active alkaline traps to determine acidic-gas ratios in volcanic plumes: Sampling techniques and analytical methods
2014
In situ measurements have been the basis for monitoring volcanic gas emissions for many years and—being complemented by remote sensing techniques—still play an important role to date. Con- cerning in situ techniques for sampling a dilute plume, an increase in accuracy and a reduction of detection limits are still necessary for most gases (e.g., CO2, SO2, HCl, HF, HBr, HI). In this work, the Raschig-Tube tech- nique (RT) is modified and utilized for application on volcanic plumes. The theoretical and experimental absorption properties of the RT and the Drechsel bottle (DB) setups are characterized and both are applied simultaneously to the well-established Filter packs technique (FP) in the …
Gene therapy for type 1 diabetes: is it ready for the clinic?
1999
This review, in addition to updating the growing list of type 1 diabetes- relevant gene therapies, offers an outline of short-term objectives that can readily be met to move, at least, adenoviral and adeno-associated viral-based protocols into the clinic, first as a means of facilitating islet allografts as well as platforms with which to introduce immunoregulatory transgenes. A wide array of genes have been tested to restore insulin production, to drive the differentiation of insulin-producing progenitors, and to confer immunosuppression in an antigen- and tissue-restricted manner.
Errors in imaging patients in the emergency setting
2016
Emergency and trauma care produces a "perfect storm" for radiological errors: uncooperative patients, inadequate histories, time-critical decisions, concurrent tasks and often junior personnel working after hours in busy emergency departments. The main cause of diagnostic errors in the emergency department is the failure to correctly interpret radiographs, and the majority of diagnoses missed on radiographs are fractures. Missed diagnoses potentially have important consequences for patients, clinicians and radiologists. Radiologists play a pivotal role in the diagnostic assessment of polytrauma patients and of patients with non-traumatic craniothoracoabdominal emergencies, and key elements …
River Contracts for Innovation in Territorial Governance
2016
Emerged in France in 1980s as agreements oriented to the requalification of rivers and lakes, river contracts represent an important outcome of the decentralization process, developed in Europe in reply to the growing institutional fragmentation. In this scenario, rivers have become a dialectic arena in which the exploitation and management of water resources came to terms with environmental instances, and offered the breeding ground for concerted efforts between policy makers, stakeholders and communities. In this chapter, the analysis is focused on the river contract model and the related set of instruments capable of supporting concerted and participatory management processes both with r…
Tertiary maars of the Hocheifel Volcanic Field, Germany
2008
In the Hocheifel only three maars are known. The Eckfeld Maar, filled with Eocene lacustrine sediments, is located at the southern boundary of the volcanic field, where the Tertiary peneplain has been eroded only slightly. The ages of the Jungferweiher Maar in the southeast and the Dottingen Maar in the northeast of the Tertiary Hocheifel Volcanic Field (THVF) are unknown and their timing within the THVF is uncertain. In contrast to the surrounding area, the central part of the THVF is deeply eroded. Here, six large diatremes (>600 m) were identified in the area of Kelberg with one exception. So far, no relics of crater sediments have been found within the large diatremes. They probably rep…
FORMATION OF PHREATOMAGMATIC MAAR–DIATREME VOLCANOES AND ITS RELEVANCE TO KIMBERLITE DIATREMES
1975
ABSTRACT Studies of maars and diatremes suggest a specific process in their formation. Magma rises along a fissure and contacts ground– or surface derived water. The resulting phreatomagmatic eruptions give rise to base surge and air–fall deposits consisting of juvenile and wall–rock material. Spalling of the wall–rocks enlarges the fissure into an embryonic vent. At a critical diameter of the vent large-scale spalling at depth and slumping near the surface gives rise to a ring–fault of large diameter and subsidence of the enclosed wall–rocks and overlying pyroclastic debris. This subsidence leads to a maar crater at the surface. Fluidization processes are active in the narrow vent and in f…
Pesticides in the Ebro River basin: Occurrence and risk assessment
2016
In this study, 50 pesticides were analyzed in the Ebro River basin in 2010 and 2011 to assess their impact in water, sediment and biota. A special emphasis was placed on the potential effects of both, individual pesticides and their mixtures, in three trophic levels (algae, daphnia and fish) using Risk Quotients (RQs) and Toxic Units (TUs) for water and sediments. Chlorpyrifos, diazinon and carbendazim were the most frequent in water (95, 95 and 70% of the samples, respectively). Imazalil (409.73 ng/L) and diuron (150 ng/L) were at the highest concentrations. Sediment and biota were less contaminated. Chlorpyrifos, diazinon and diclofenthion were the most frequent in sediments (82, 45 and 2…
Es pot naturalitzar la intencionalitat?
2016
Resum: La intencionalitat és un element central en la nostra comprensió del món. Diàriament atribuïm estats intencionals (com ara creences, desitjos o percepcions) per a poder explicar el comportament d’altres agents, i moltes teories filosòfiques hi apel·len per a entendre altres nocions més complexes. Tanmateix, els estats intencionals són entitats enigmàtiques. Aquest article explica què és la intencionalitat i per què és tan important i problemàtica alhora. En segon lloc, examina diverses teories naturalistes que intenten mostrar que la intencionalitat és compatible amb una visió científica del món. Finalment, com que totes les propostes existents s’enfronten a dificultats significative…
Evaluation of 2,3-epoxypropyl groups and functionalization yield in glycidyl methacrylate monoliths using gas chromatography
2014
Abstract Poly(glycidyl methacrylate- co -ethylene dimethacrylate) (poly(GMA- co -EDMA)) is most frequently used as parent monolith to obtain stationary phases with a variety of surface chemistries for liquid chromatography and capillary electrochromatography. Functionalization is performed by opening the accessible 2,3-epoxypropyl groups of the monolith with a suitable reagent. The number of 2,3-epoxypropyl groups which are accessible before and after the functionalization reaction, and the grafting yield, are important parameters, required both to optimize functionalization and to interpret the chromatographic performance of functionalized monoliths. In this work, a method capable of provi…