10,246 research outputs found
How to guarantee the natural origin of nutraceutical and pharmaceutical products? The potential of the stable isotope ratios analysis
The analysis of the ratio between the heavy and light isotopes of the elements carbon (13C/12C), nitrogen (15N/14N), sulfur (34S/32S), oxygen (18O/16O) and hydrogen (2H/1H) is well known for its power to discriminate the geographical origin and guarantee the authenticity of many agri-food products [1]. In recent years, the field of application of this technique has expanded to include nutraceuticals and pharmaceuticals, in particular in order to guarantee their natural origin. Chemically identical molecules are significantly different from an isotopic point of view due to the isotopic fractionation that occurs in different processes and reactions (biological, biochemical, physical, chemical, etc.) which generates unique isotopic signatures in the product synthesized by plants compared to that produced in the laboratory usually starting from fossil sources. Thanks to the coupling of isotopic mass spectrometry to liquid chromatography (LC-IRMS) and gas chromatography (GC-IRMS) it is now possible to discriminate between natural and/or synthetic origin not only of the bulk product but also of its specific components. The "Compound specific analysis" makes it possible to identify much more sophisticated frauds than in the past such as, for example, the addition of a single synthetic component to a natural substrate in order to artificially increase its strength. In this context, the δ13C analysis is a suitable tool to discriminate between Monacolin K (contained in red yeast rice-based dietary supplements) and the marketed statin [2] and between natural L-theanine (extracted from Camellia Sinensis) and the biosynthetically produced one [3]. The isotope ratios of hydrogen and, in some cases, carbon exhibit significantly different ranges of variability between natural extracts (such as curcuminoids [4] and cannabidiols [5]) and their synthetic adulterant, allowing for the identification of not only the two origins, but also the fraudulent additions of synthetic products to the natural complex (spiked samples). The combination of GC-MS/MS and GC-IRMS is potentially useful for botanical classification between lavender (Lavandula angostifolia) and lavandin (Lavandula hybrida) essential oils thus representing an additional powerful tool for assessing the authenticity of commercial essential oil
Physical interaction between MYCN oncogene and polycomb repressive complex 2 (PRC2) in neuroblastoma: Functional and therapeutic implications
This article is made available through the Brunel Open Access Publishing Fund. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.CLU (clusterin) is a tumor suppressor gene that we have previously shown to be negatively modulated by the MYCN proto-oncogene, but the mechanism of repression was unclear. Here, we show that MYCN inhibits the expression of CLU by direct interaction with the non-canonical E box sequence CACGCG in the 5′-flanking region. Binding of MYCN to the CLU gene induces bivalent epigenetic marks and recruitment of repressive proteins such as histone deacetylases and Polycomb members. MYCN physically binds in vitro and in vivo to EZH2, a component of the Polycomb repressive complex 2, required to repress CLU. Notably, EZH2 interacts with the Myc box domain 3, a segment of MYC known to be essential for its transforming effects. The expression of CLU can be restored in MYCN-amplified cells by epigenetic drugs with therapeutic results. Importantly, the anticancer effects of the drugs are ablated if CLU expression is blunted by RNA interference. Our study implies that MYC tumorigenesis can be effectively antagonized by epigenetic drugs that interfere with the recruitment of chromatin modifiers at repressive E boxes of tumor suppressor genes such as CLU.SPARKS, The Neuroblastoma Society,
a Wellcome Trust grant (to A. S.), and the Italian Association for Cancer
Research
Summary of the CMS Discovery Potential for the MSSM SUSY Higgses
This work summarises the present understanding of the expected MSSM SUSY
Higgs reach for CMS. Many of the studies presented here result from detailed
detector simulations incorporating final CMS detector design and response. With
30 fb-1 the h -> gamma,gamma and h -> bb channels allow to cover most of the
MSSM parameter space. For the massive A,H,H+ MSSM Higgs states the channels A,H
-> tau,tau and H+ -> tau,nu turn out to be the most profitable ones in terms of
mass reach and parameter space coverage. Consequently CMS has made a big effort
to trigger efficiently on taus. Provided neutralinos and sleptons are not too
heavy, there is an interesting complementarity in the reaches for A,H ->
tau,tau and A,H -> chi,chi.Comment: 19 pages, 27 figure
DC and AC Electrical Characterization of Stacks of HTS Tapes
Today the Bi-2223 tape represents a suitable candidate for the use in various HTS devices. The LHC current leads use Bi-2223 tapes soldered together in short lengths, forming stacks of rugged HTS conductors. Critical current and AC loss measurements were performed on BSCCO stacks, in the temperature range of 65 K and 77 K and in magnetic fields of up to 0.5 T. The experimental results reported in this paper give a broad description of the stacks behavior in the range of current and field values of practical interest, and provide design parameters for the optimization of current leads operating both in DC and pulsed conditions
BAFF Index and CXCL13 levels in the cerebrospinal fluid associate respectively with intrathecal IgG synthesis and cortical atrophy in multiple sclerosis at clinical onset
Abstract
Background
B lymphocytes are thought to play a relevant role in multiple sclerosis (MS) pathology. The in vivo analysis of intrathecally produced B cell-related cytokines may help to clarify the mechanisms of B cell recruitment and immunoglobulin production within the central nervous system (CNS) in MS.
Methods
Paired cerebrospinal fluid (CSF) and serum specimens from 40 clinically isolated syndrome suggestive of MS or early-onset relapsing-remitting MS patients (CIS/eRRMS) and 17 healthy controls (HC) were analyzed for the intrathecal synthesis of IgG (quantitative formulae and IgG oligoclonal bands, IgGOB), CXCL13, BAFF, and IL-21. 3D-FLAIR, 3D-DIR, and 3D-T1 MRI sequences were applied to evaluate white matter (WM) and gray matter (GM) lesions and global cortical thickness (gCTh).
Results
Compared to HC, CIS/eRRMS having IgGOB (IgGOB+, 26 patients) had higher intrathecal IgG indexes ( p \u2009<\u20090.01), lower values of BAFF Index (11.9\u2009\ub1\u20096.1 vs 17.5\u2009\ub1\u20095.2, p \u2009<\u20090.01), and higher CSF CXCL13 levels (27.7\u2009\ub1\u200933.5 vs 0.9\u2009\ub1\u20091.5, p \u2009<\u20090.005). In these patients, BAFF Index but not CSF CXCL13 levels inversely correlated with the intrathecal IgG synthesis ( r \u2009>\u20090.5 and p \u2009<\u20090.05 for all correlations). CSF leukocyte counts were significantly higher in IgGOB+ compared to IgGOB\u2212 ( p \u2009<\u20090.05) and HC ( p \u2009<\u20090.01), and correlated to CSF CXCL13 concentrations ( r 0.77, p \u2009<\u20090.001).
The gCTh was significantly lower in patients with higher CSF CXCL13 levels (2.41\u2009\ub1\u20090.1 vs 2.49\u2009\ub1\u20090.1\ua0mm, p \u2009<\u20090.05), while no difference in MRI parameters of WM and GM pathology was observed between IgGOB+ and IgGOB\u2212.
Conclusions
The intrathecal IgG synthesis inversely correlated with BAFF Index and showed no correlation with CSF CXCL13. These findings seem to indicate that intrathecally synthesized IgG are produced by long-term PCs that have entered the CNS from the peripheral blood, rather than produced by PCs developed in the meningeal follicle-like structures (FLS). In this study, CXCL13 identifies a subgroup of MS patients characterized by ..
High density balsamic vinegar: application of stable isotope ratio analysis to determine watering down
Aceto balsamico di Modena IGP (ABM) is an Italian worldwide appreciated PGI (Protected Geographical Indication) vinegar, obtained from cooked and/or concentrated grape must (at least 20% of the volume), with the addition of at least 10% of wine vinegar and a maximum 2% of caramel for color stability (EU Reg. 583/ 2009). The geographical origin of ABM ingredients is never specified. Since 2013, the European Committee for Standardization (CEN) has issued a method for determining the water fraudulently added to the vinegar and the balsamic vinegar product (EN16466-3 18O-IRMS). The method is based on the stable isotope ratios analysis of the bulk AMB sample (expressed as δ18O in ‰ with respect to the international standard V-SMOW2). Balsamic vinegars with very high density (higher than 1.37 g / mL of sugar) are available on the market. They are obtained by adding a high amount of concentrated must or by a long aging of the product in the barrel, which leads to an intense evaporation and concentration. Products with such high density cannot be analyzed by using the official method as reported in the EN16466-3 18O-IRMS. Indeed, in this conditions, the equilibration between CO2 and the water in the sample, being the base principle of the process, does not occur. In this work, the official method has been modified and validated, calculating repeatability (r) and reproducibility (R), by proceeding with a prior dilution of the sample and by applying a correction to the data in order to eliminate the diluent isotopic contribution. Considering the limit value of δ18O for a non-watered product reported in the literature for vinegar and for rectified concentrated must [1-2], the threshold limit of δ18O below which the ABM product can be considered as adulterated was identified. References [1] J. Agric. Food Chem. 2014, 62, 32, 8197–8203 [2] Food Control 2013, 29(1), 107–11
Authentication and geographical characterisation of Italian grape musts through glucose and fructose carbon isotopic ratios determined by LC IRM
The authenticity of grape musts is normally checked through the stable isotopic analysis of carbon (δ13C) after fermentation and distillation by following the official OIV MA AS-312-06 method. Unfortunately, it presents some issues that are difficult to over come. Grape must samples can only be analysed after they have been fermented to obtain ethanol. The process must be carried out under careful control of the fermentation to avoid the presence of unwanted by-products arising from a premature fermentation interruption. Moreover, if the musts have been preserved by the addition of sulphur dioxide (SO2 ), they must undergo an additional step to eliminate the SO2 , which would affect the fermentation. Once the product has been fermented, the ethanol must be separated using specific distillation columns (such as the Cadiot ones) making it possible to obtain ethanol free of isotopic fractionation with a minimum alcohol degree of 95% vol. In this study, the alternative use of a technique based on δ13C isotopic analysis of the major sugars of the grape must by liquid chromatography coupled with isotope ratio mass spectrometry (LC-IRMS) is provided. In LC–IRMS, analytes are separated on an LC system and consecutively oxidized in an online reactor to CO2 , which is required for the determination of compound-specific carbon isotopic ratios. This technique has been already used in the study of matrices such as wine [1], ethanol [1,2], glycerol [2], and honey [3] to detect fraudulent alterations of their natural composition such as the addition of exogenous sugars to the products. The LC-IRMS allows a single separation of the individual components of a sample and makes it possible to determine their δ13C values online, avoiding both the disadvantages of off-line methods and the disadvantages of methods requiring a derivatization step (such as GC-C-IRMS), causing the addition of extra carbons. In order to discriminate between musts from different areas of Italy, a preliminary dataset was considered; the δ13C isotopic ratios of glucose and fructose of around 100 authentic Italian must samples from 16 different sampling regions were analysed. In addition, the δ13C variability in authentic and fake must (added with increasing percentages of exogenous sugars) has been explored and tested to verify their validity as fraud detectors. The two analysed parameters, ranging from −29.8‰ to −21.9‰, are well correlated (R2 = 0.7802) and the northern Italian regions showed significantly more negative δ13C values for both sugars than the rest of the dataset (Figure 1). By using the LC-IRMS technique, the addition of exogenous sugars, such as fructose and glucose from C4 photosynthetic cycle plants, is easily detectable as it modifies the δ13C of the individual sugar
Analyzing requirements of knowledge management systems with the support of agent organizations
Spinfoams in the holomorphic representation
We study a holomorphic representation for spinfoams. The representation is
obtained via the Ashtekar-Lewandowski-Marolf-Mour\~ao-Thiemann coherent state
transform. We derive the expression of the 4d spinfoam vertex for Euclidean and
for Lorentzian gravity in the holomorphic representation. The advantage of this
representation rests on the fact that the variables used have a clear
interpretation in terms of a classical intrinsic and extrinsic geometry of
space. We show how the peakedness on the extrinsic geometry selects a single
exponential of the Regge action in the semiclassical large-scale asymptotics of
the spinfoam vertex.Comment: 10 pages, 1 figure, published versio
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