47 research outputs found
Harmonization of VFAs measurement by GC: something more than R2 to evaluate the calibration function
Anaerobic digestion is sensitive to many environmental factors requiring a robust control of this process. One of the analytical measurements considered as key parameter is the volatile fatty acids (VFAs) content. Total amount of volatile acids (TVFA) to control the relative changes over time has been suggested as a useful tool. However, TVFA does not provide sufficient information to reveal the overall reactor performance, and individual components have been considered of particular interest. Although some attempts have been described as on-line measurements for individual VFAs, normally they are determined by off-line chromatographic techniques (GC and HPLC). A previous interlaboratory study showed the lack of harmonization in the analytical methodologies dealing to individual VFAs, and giving an overall analytical performance rather poor. One of the reasons to justify these results was the inappropriate calibration procedures. It is widely used to check the linearity of the calibration curves based on the correlation and determination coefficients. However, these statistical parameters are erroneously interpreted. The objective of this interlaboratory study was to achieve the harmonization of results. By this way, the use of internal standard methodology (ISTD) should be useful to obtain accurate calibration functions. In addition, five different statistical parameters such as lack of fit test, residual standard deviation, relative standard deviation of the slope, relative standard deviation of the sensitivity and relative error were proposed to evaluate the linearity of calibration curves. Of these, lack of fit was unable to detect appropriately the linearity mainly due to its sensitivity to the precision of analytical results. The rest of statistical parameters reported could be considered as starting point for comparative purposes, being useful as acceptance criteria. The principal advantage of the GC/ISTD analytical methodology was the normalization of the slopes obtained by the participating laboratories, being very helpful to the harmonization of results.Peer Reviewe
A multicentre outcome analysis to define global benchmarks for donation after circulatory death liver transplantation
Cellular mechanisms in basic and clinical gastroenterology and hepatolog
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Triptolide and Trail Combination Enhances Cell Death via Apoptosis in Cholangiocarcinoma Cells
Myricetin induces pancreatic cancer cell death via the induction of apoptosis and inhibition of the phosphatidylinositol 3-kinase (PI3K) signaling pathway
Pancreatic cancer is the fourth leading cause of cancer related deaths and is a disease with poor prognosis. It is refractory to standard chemotherapeutic drugs or to novel treatment modalities, making it imperative to find new treatments. In this study, using both primary and metastatic pancreatic cancer cell lines, we have demonstrated that the flavonoid myricetin induced pancreatic cancer cell death
in vitro via apoptosis, and caused a decrease in PI3 kinase activity.
In vivo, treatment of orthotopic pancreatic tumors with myricetin resulted in tumor regression and decreased metastatic spread. Importantly, myricetin was non-toxic, both
in vitro and
in vivo, underscoring its use as a therapeutic agent against pancreatic cancer
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73. Triptolide Therapy for Neuroblastoma Decreases Cell Viability in Vitro and Inhibits Tumor Growth in Vivo
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DELIVERY OF siRNA TO PANCREATIC CANCER CELLS USING NOVEL NON-VIRAL BIODEGRADABLE NANOPARTICLES
Harmonization of the quantitative determination of volatile fatty acids profile in aqueous matrix samples by direct injection using gas chromatography and high-performance liquid chromatography techniques: Multi-laboratory validation study
The performance parameters of volatile fatty acids (VFAs) measurements were assessed for the first time by a multi-laboratory validation study among 13 laboratories. Two chromatographic techniques (GC and HPLC) and two quantification methods such as external and internal standard (ESTD/ISTD) were combined in three different methodologies GC/ESTD, HPLC/ESTD and GC/ISTD. Linearity evaluation of the calibration functions in a wide concentration range (10-1000mg/L) was carried out using different statistical parameters for the goodness of fit. Both chromatographic techniques were considered similarly accurate. The use of GC/ISTD, despite showing similar analytical performance to the other methodologies, can be considered useful for the harmonization of VFAs analytical methodology taking into account the normalization of slope values used for the calculation of VFAs concentrations. Acceptance criteria for VFAs performance parameters of the multi-laboratory validation study should be established as follows: (1) instrument precision (RSDINST≤1.5%); (2) linearity (R2≥0.998; RSDSENSITIVITY≤4%; REMAX≤8%; REAVER≤ 3%); (3) precision (RSD≤1.5%); (4) trueness (recovery of 97-103%); (5) LOD (≤3mg/L); and (6) LOQ (10mg/L
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TRIPTOLIDE INHIBITS TUMOR GROWTH AND LOCAL-REGIONAL SPREAD IN VIVO VIA INCREASED APOPTOSIS AND DECREASED HEAT SHOCK PROTEIN 70 (HSP70)
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