3,646 research outputs found
Calcined and uncalcined carbonate layered double hydroxides for possible water defluoridation in rural communities of the East African Rift Valley
No full textHealth risks linked to the regular consumption of water with high fluoride (F − ) content seriously affect rural areas of the East African Rift Valley. The F − removal capacity has been tested on uncalcined and calcined carbonate layered double hydroxides (LDHs), with different cationic compositions (M 2+ = Mg 2+ , Zn 2+ ; M 3+ = Al 3+ , Fe 3+ ) and M 2+ /M 3+ molar ratio (2, 3, 4), taking into account the necessity of a simple defluoridation method. The 3MgAlFe-cal phase derived from calcination of a hydrotalcite-like compound with composition Mg/(Al + Fe) = 3/(0.5 + 0.5) results to be the best F − remover (43 mg/g) and can uptake up to 92.3 mg/g when the interlayer is fully saturated with F − . At the high pH reached during the experiments (up to pH 12 for calcined LDHs), the presence of carbonate species in solution significantly affects the F − removal capacity. The recyclability of the sorbent was tested by regeneration through calcination of the 3MgAlFe-cal phase: under F − unsaturated interlayer conditions, up to 80% of the starting F − removal capacity is still preserved after four regeneration cycles, indicating that LDHs can be reused after regeneration and have a potential use in water defluoridation
Prognostic markers and putative therapeutic targets for hepatocellular carcinoma.
No full textMol Aspects Med. 2010 Apr;31(2):179-93. Epub 2010 Feb 20.
Prognostic markers and putative therapeutic targets for hepatocellular carcinoma.
Frau M, Biasi F, Feo F, Pascale RM.
Source
Department of Biomedical Sciences, Division of Experimental Pathology and Oncology, University of Sassari, 07100 Sassari, Italy.
Abstract
Hepatocellular carcinoma (HCC) is the fifth most frequent human cancer and a fatal disease. Therapies with pharmacological agents do not improve the prognosis of patients with unresectable HCC. This emphasizes the need to identify new targets for early diagnosis, chemoprevention, and treatment of the disease. Available evidence indicates that clinical outcome of HCC could reflect the genetic predisposition to cancer development and progression. Numerous loci controlling HCC progression have been identified in rodents. In this review, we describe results of recent studies on effector mechanisms of susceptibility/resistance genes, responsible for HCC progression, aimed at identifying new putative prognostic markers and therapeutic targets of this tumor. Highest c-myc amplification and overexpression, alterations of iNOS crosstalk with IKK/NF-kB and RAS/ERK signaling, ubiquitination of ERK and cell cycle inhibitors, and deregulation of FOXM1 and cell cycle key genes occur in rapidly progressing dysplastic nodules and HCC, induced in genetic susceptible rat strains, compared to the lesions of resistant rats. Notably, alterations of these mechanisms in human HCC subtypes with poorer or better prognosis, are similar to those present in genetically susceptible and resistant rats, respectively, and function as prognostic markers and therapeutic targets. Attempts to cure advanced HCC by molecular therapy directed against specific targets led to modest survival benefit. Thus, efforts are necessary to identify and test, in pre-clinical and clinical studies, new therapeutic targets for combined molecular treatments of HCC. They may take advantage from the comparative analysis of signal transduction in HCCs differently prone to progress, in rats and humans
Acid production by FeSO4•nH2O dissolution: Comment
No full textDissolution of natural and commercial melanterite generates a significant decrease in pH that is not thermodynamically explained by Fe(2+) hydrolysis. It has been recently proposed that the production of acidity is actually caused by hydrolysis of Fe(3+) occurring in trace amounts in melanterite. Following this finding, the experiments of melanterite dissolution previously conducted by the author have been reviewed and modeled with PHREEQC. Without invoking oxidation of Fe(2+) to Fe(3+), modeling results indicate that the amount of Fe(3+) needed to significantly decrease solution pH is low (0.16-0.20 wt%) and already contained in melanterite in the form of contaminant
Mineralogical and geochemical techniques to investigate the relationships between minerals and contaminants in supergenic environments: an update review
No full textThe relationships between minerals and contaminants are an important topic of Environmental Mineralogy and Geochemistry. A multi-scale, multidisciplinary analytical approach is peculiar to both field-and laboratory-oriented studies conducted by means of the combined use of traditional and advanced analytical techniques available either in conventional laboratories or in synchrotron analytical facilities. An important objective in this type of studies is to develop models capable to relate molecular-and micro-scale data to macroscopic observations, i.e. mechanistic models. This is probably the greatest challenge in the near future of Environmental Mineralogy and Geochemistry
Geochemistry of lead at the old mine area of Baccu Locci (South-East Sardinia, Italy)
No full textAbout a century of exploitation of the galena-arsenopyrite deposit of Baccu Locci in Sardinia (Italy) has caused a
severe, persistent arsenic contamination that extends downstream of the mine for several kilometres. Differently
from As, the aqueous contamination of lead is only localised in the upper part of the mine despite very high Pb
concentrations in geologic materials (waste rocks, tailings, stream sediments, soils) over the whole Baccu Locci
stream catchment. The determination of aqueous and solid Pb speciation in various environmental media of the
Baccu Locci system has pointed out that the peculiar geochemical behaviour of Pb is mainly due to (i) the short
residence time of dissolved Pb in surface and ground water under near-neutral pH conditions and (ii) the low
solubility of plumbojarosite that represents the main secondary Pb-bearing mineral in the Baccu Locci
environment
Field evidences on release/removal of arsenic by hydrotalcite-like compounds in mining waters. The example of Baccu Locci mine (Sardinia, Italy)
No full textMinerals belonging to the hydrotalcite group are assuming an increasing interest in environmental mineralogy. In
fact, thanks to a high anionic exchange capacity, they can find applications in site-remediation as contaminant
removers from polluted waters. The presence of hydrotalcite-like sulphates such as glaucocerinite,
zincowoodwardite, hydrowoodwardite and woodwardite [Me2+
1-xAlx(SO4)x/2(OH)2·mH2O] has been documented
in a number of mining areas. They usually occur as fine-grained precipitates from mining waters or as porous
crusts. While their role on removing cations such as Zn, Cu and Al from waters is immediately evident, the role
they have in incorporating undesirable anions, other than (SO4)2-, is often disregarded. However, field evidences
from a mine area in Sardinia (Italy) showed that these phases have a great capability to remove arsenic, probably
as (AsO4)3-, from waters. The advantage of these hydrotalcites-like sulphates, in comparison with Fe-oxideshydroxides
(generally considered the most efficient arsenic removers, naturally occurring in mining areas), is to
act as removers in waters at high pH values, when a reduced efficiency of Fe-oxides-hydroxides for arsenic
sorption and a greater arsenic mobility account for an increased arsenic hazard
Mineral-contaminant relationships: Towards a multi-scale, multidisciplinary analytical approach. Preface
No full textMineralogical-geochemical study of the anionic competition effect on the octacalcium phosphate reaction into fluorapatite
No full textThe unstable compound octacalcium phosphate (OCP) is one of the crystalline precursors of the apatite mineral series composed by hydroxyapatite, fluorapatite and chlorapatite. The feature of OCP to react into apatite, depending on the media conditions, has been mainly exploited for biomedical applications as bone and tooth substitute material. Recently, some important applications of OCP have been documented: e.g. as electrode material for supercapacitors and as fluoride remover reagent for environmental purposes. With the aim of deepening the property of OCP to be the crystalline precursor of apatite and assessing if and how the anionic competition can influence the formation of the different apatite end-members, the OCP → apatite reaction has been here investigated placing 0.223 mmol of OCP in 50 mL aqueous solution with 0.368 mmol of dissolved fluoride, chloride, hydroxyl and carbonate anions (fluoride alone, fluoride with each of the other anions, and all the anions together) at room temperature. The post-experiment analyses of solid and liquid phases, conducted by using XRD, ESEM and ICP-OES, show that fluoride is always the main anion removed from solution during the OCP transformation reaction. The precise mineralogical characterization of solid phases formed, performed using the Rietveld algorithm, shows that fluorapatite is always the main resulting apatitic phase, followed by hydroxyapatite. Taking into account the different application fields of OCP, these results could be significant in better defining the OCP → apatite reaction in aqueous solutions where different competing anions are involved
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