Search results for " Phase"
showing 10 items of 1862 documents
Thermodynamics and Structure of Plate-Like Particle Dispersions
2012
A considerable amount of mineral particles are found to have a plate-like shape. The work in this thesis concerns theoretical investigations, using a Monte Carlo method, of the properties of such particles in aqueous solutions. The objectives were first to create a model that could capture the essential physics of clay suspensions and also to understand the role of thermodynamics in certain chemical processes. For all investigations, the results are related to experimental studies. The acid-base behavior of clays have been studied, using the primitive model, and an excellent agreement between simulated and experimental results was found. The formation of gel phases as a function of the char…
LC of high to moderately polar basic drugs in urine with water and detergent, and direct injection
2016
Background: Micellar LC was first proposed as a ‘green’ mode using mobile phases of water and surfactant. However, in most procedures a small amount of organic solvent is required to decrease the retention to convenient values. Results & methodology: Mixed micellar mobile phases prepared with both cationic (sodium dodecyl sulphate) and nonionic surfactant (Brij-35) modulate the retention of high to moderately polar basic drugs to practical times, eliminating the need of organic solvent. While the mobile phase is continuously recycled through the system, the stationary phase performance is maintained after repetitive injection of the samples. Discussion & conclusion: Through an exte…
Determination of benzomercaptans in environmental complex samples by combining zeolitic imidazolate framework-8-based solid-phase extraction and high…
2020
[EN] In this work, the synthesis of zeolitic imidazolate framework-8 (ZIF-8) crystals and their subsequent application as effective sorbents for extraction and preconcentration of several benzomercaptans from environmental complex samples is described. These materials were prepared by solvothermal approach varying the concentration of n-butylamine modulator to modify the surface of the metal-organic framework. The resulting materials were characterized by scanning and transmission electron microscopy, powder X-ray diffraction and Fourier transform infrared spectroscopy. The ZIF-8 material that gave the best features was selected as extractive phase and the influence of various parameters (s…
Volatile profiles of Sicilian prickly pear (Opuntia ficus indica) by SPME-GC/MS analysis
2005
The aroma compounds present in the headspace of homogenized slurries of fresh prickly pears (Opuntia ficus-indica) from Sicilian cultivars were determined. Solid Phase Microextraction (SPME) followed by Gas-chromatography/Mass Spectrometry (GC/MS) analysis was used to characterize the volatile compounds. The volatile flavour profiles of the three cultivars investigated (red, white and yellow) showed significant differences. The aromatic profile of peeled prickly pears stored for one day was different from the one of the fresh samples, mainly due to the occurrence of some oxidative and hydrolytic reactions
Host–guest complexes of conformationally flexible C-hexyl-2-bromoresorcinarene and aromatic N-oxides: solid-state, solution and computational studies
2018
Host–guest complexes of C-hexyl-2-bromoresorcinarene (BrC6) with twelve potential aromatic N-oxide guests were studied using single crystal X-ray diffraction analysis and 1H NMR spectroscopy. In the solid state, of the nine obtained X-ray crystal structures, eight were consistent with the formation of BrC6-N-oxide endo complexes. The lone exception was from the association between 4-phenylpyridine N-oxide and BrC6, in that case the host forms a self-inclusion complex. BrC6, as opposed to more rigid previously studied C-ethyl-2-bromoresorcinarene and C-propyl-2-bromoresorcinarene, undergoes remarkable cavity conformational changes to host different N-oxide guests through C–H···π(host) intera…
Determination of organophosphate flame retardants in soil and fish using ultrasound-assisted extraction, solid-phase clean-up, and liquid chromatogra…
2017
A solid–liquid extraction method in combination with high‐performance liquid chromatography and tandem mass spectrometry was developed and optimized for extraction and analysis of organophosphorus flame retardants in soil and fish. Methanol was chosen as the optimum extraction solvent, not only in terms of extraction efficiency, but also for its broader analyte coverage. The subsequent clean‐up by solid‐phase extraction is required to eliminate matrix coextractives and reduce matrix effects. Recoveries of the optimized method were 50–121% for soil and 47–123% for biota, both with high precision (RSDs <12% in soil and <23% in biota). The method limits of detection ranged from 0.06 to 0.20 ng…
Nuove ricerche a Solunto (2021)
2021
New researches in Solunto (2021) · The paper presents an overview of the ongoing researches in Solunto by the University of Palermo. In 2021 stratigraphical sondages were undertaken in two areas of the town: 1) in the great sanctuary above the theatre, in the frame of a major project aimed at addressing several still unresolved issues. That area, as a matter of fact, has never been considered as a whole; the sacred buildings have not been studied, and their mutual relationships and the links with the adjacent terraces have never been properly examined; 2) in the North Baths near the agora, as a corollary of the systematic study of water management, some sondages were made by G. Polizzi. Fin…
HCC therapies--lessons learned.
2014
The antiangiogenic multikinase inhibitor sorafenib was the first systemic agent to demonstrate a significant improvement in the overall survival of patients with advanced hepatocellular carcinoma (HCC), thereby introducing molecularly-targeted therapy in a therapeutic field of unmet needs. However, survival benefits for patients on sorafenib treatment are modest in clinical practice and advancing the field is far more challenging than initially anticipated. Molecular and clinical heterogeneity diminishes signals of potential activity in unselected populations, and underlying liver cirrhosis seals the fate of many novel targeted agents by causing relevant toxicity and mortality. The failure …
Outcomes of hepatocellular carcinoma patients treated with sorafenib: a meta-analysis of Phase III trials
2019
Aim: To benchmark overall survival (OS) and time to radiological progression (TTP) of patients enrolled in randomized controlled trials (RCTs) assessing sorafenib in advanced hepatocellular carcinoma using individual participant survival data, and to meta-analyze prognostic factors for OS and TTP. Methods: RCTs were identified through literature search until December 2018. Individual participant survival was reconstructed with an algorithm from published Kaplan–Meier curves. Results: Ten RCTs were included. Median OS was 10.0 months (95% CI: 9.6–10.5), and median TTP was 4.1 months (95% CI: 3.8–4.3). Multivariable analyses showed HCV positivity, absence of macrovascular invasion and extra-…
Enhancing extraction performance of organophosphorus flame retardants in water samples using titanium hierarchical porous silica materials as sorbent…
2021
Abstract A sorbent for the extraction of organophosphorus flame retardants has been proposed, based on UVM-7 (University of Valencia Materials) mesoporous silica doped with titanium. Designed cartridges have been applied to the extraction and preconcentration of flame retardants in water samples, followed by gas chromatography coupled to a mass spectrometry detector. Firstly, UVM-7 materials with different contents of titanium were synthesized and characterized by several techniques, thus confirming the proper mesoporous architecture. The potential of these materials was assessed in comparison with their morphological properties, resulting Ti50-UVM-7 the best solid phase. Several extraction…