Search results for " Reverse"

Short telomeres drive pessimistic judgement bias in zebrafish.

2021

The role of telomerase reverse transcriptase has been widely investigated in the contexts of ageing and age-related diseases. Interestingly, decreased telomerase activities (and accelerated telomere shortening) have also been reported in patients with emotion-related disorders, opening the possibility for subjective appraisal of stressful stimuli playing a key role in stress-driven telomere shortening. In fact, patients showing a pessimistic judgement bias have shorter telomeres. However, in humans the evidence for this is correlational and the causal directionality between pessimism and telomere shortening has not been established experimentally yet. We have developed and validated a judg…

The role of the dual nature of ionic liquids in the reversed-phase liquid chromatographic separation of basic drugs.

2010

The cationic nature of basic drugs gives rise to broad asymmetrical chromatographic peaks with conventional C18 columns and hydro-organic mixtures, due to the ionic interaction of the positively charged solutes with the free silanol groups on the alkyl-bonded reversed-phase packing. Ionic liquids (ILs) have recently attracted some attention to reduce this undesirable silanol activity. ILs are dual modifiers (with a cationic and anionic character), which means that both cation and anion can be adsorbed on the stationary phase, giving rise to interesting interactions with the anionic free silanols and the cationic basic drugs. A comparative study of the performance of four imidazolium-based I…

Experimental assessment of reverse electrodialysis in closed loop configuration fed by NH4HCO3-water solutions

2018

Closed loop reverse electrodialysis is a novel technology for converting low-temperature waste heat into electric energy. This innovative heat engine consists of two units: (i) a reverse electrodialysis unit where power is produced exploiting the concentration difference between a diluted and a concentrated salt solution and (ii) a thermally driven regeneration unit where low-grade waste heat is used to re-establish the original salinity gradient between the two salt solutions. Among all the possible salt solutions suitable as working fluid in such application, Thermolytic salts solutions, in particular Ammonium bicarbonate solutions, may be promising thanks to their characteristic thermall…

The Problem of Time Arrow in Financial Time Series

According to the efficient market hypothesis, future movements of the market cannot be predicted. This introduces an intrinsic time asymmetry of the financial time series as there are no laws forbidding “predicting” past based on the current market fluctuations. This clear time asymmetry in the basic laws of finance raises a question which we shall be referring to as the problem of time arrow: are there any noticeable statistical differences between forward-in-time and reverse-in-time market data. Majority of the statistical methods used for financial time series are time-symmetric and hence, not usable for our purposes. The first method used in our study is the analysis of the length-distr…

The predictive power of power-laws: An empirical time-arrow based investigation

2022

The efficient market hypothesis forbids any predictability towards future, but there is no such restriction in the case of reversed-looking approaches. We analyze if this asymmetry in non-predictability is reflected in the statistical features of financial time series. Our study is based on the analysis of the length-distribution of periods with high variability, and introduces time-asymmetric modifications of the method which are capable of revealing differences of the time series in forward and reversed time. We show that the future and reversed-looking time-series possess very similar properties, with some features being distinguishable with our method. Our findings give also evidence of…

Pievienotās vērtības nodokļa apgrieztās maksāšanas kārtības pielietojuma analīze

2020

Diplomdarba “Pievienotās vērtības nodokļa apgrieztās maksāšanas kārtības pielietojuma analīze” aktualitāte – izvairīšanās no PVN rada ievērojamus zaudējumus valstij, viens no risinājumiem ir PVN apgrieztās maksāšanas kārtības ieviešana nozarēs, kur pastāv liels PVN krāpšanās risks. Darba mērķis - izpētot PVN apgrieztās maksāšanas kārtības būtību, normatīvo regulējumu, un veicot LR „Pievienotās vērtības nodokļa likuma” 141. panta līdz 143.5 panta prasību piemērošanas analīzi, atklāt praksē novērotās kārtības piemērošanas trūkumus un nepilnības, izstrādāt priekšlikumus atbildīgajām institūcijām par PVN apgrieztās maksāšanas kārtības pilnveidošanu. Secināts, ka PVN apgrieztās maksāšanas kārtīb…

Synthesis of honokiol analogues and evaluation of their modulating action on VEGF protein secretion and telomerase-related gene expressions

2017

A group of 36 biphenyl derivatives structurally related to honokiol were synthesized by means of Suzuki coupling reactions. Their cytotoxicities were evaluated and compared to that of honokiol. Some of the compounds were then evaluated for their ability to downregulate the secretion of the VEGF protein and the expression of the VEGF, hTERT, and c-Myc genes; the two latter involved in the activation of telomerase in tumoral cells. Some of the synthetized derivatives showed promising pharmacological features as they exhibited IC50 values in low micromolar range, good therapeutic margins, and a multiple mode of action on tumor cells based on the inhibition of VEGF and, at the same time, of the…

The impact of tumor nitric oxide production on VEGFA expression and tumor growth in a zebrafish rat glioma xenograft model.

2015

International audience; To investigate the effect of nitric oxide on tumor development, we established a rat tumor xenograft model in zebrafish embryos. The injected tumor cells formed masses in which nitric oxide production could be detected by the use of the cell-permeant DAF-FM-DA (diaminofluorophore 4-amino-5-methylamino-2'-7'-difluorofluorescein diacetate) and DAR-4M-AM (diaminorhodamine-4M). This method revealed that nitric oxide production could be co-localized with the tumor xenograft in 46% of the embryos. In 85% of these embryos, tumors were vascularized and blood vessels were observed on day 4 post injection. Furthermore, we demonstrated by qRT-PCR that the transplanted glioma ce…

Hypoxia Positively Regulates the Expression of pH-Sensing G-Protein–Coupled Receptor OGR1 (GPR68)

2016

Background & Aims: A novel family of proton-sensing G-proteinâcoupled receptors, including ovarian cancer G-proteinâcoupled receptor 1 (OGR1) (GPR68) has been identified to play a role in pH homeostasis. Hypoxia is known to change tissue pH as a result of anaerobic glucose metabolism through the stabilization of hypoxia-inducible factor-1α. We investigated how hypoxia regulates the expression of OGR1 in the intestinal mucosa and associated cells. Methods: OGR1 expression in murine tumors, human colonic tissue, and myeloid cells was determined by quantitative reverse-transcription polymerase chain reaction. The influence of hypoxia on OGR1 expression was studied in monocytes/macrophages and…

Thermolytic reverse electrodialysis heat engine: model development, integration and performance analysis

2019

Abstract Salinity gradient heat engines represent an innovative and promising way to convert low-grade heat into electricity by employing salinity gradient technology in a closed-loop configuration. Among the aqueous solutions which can be used as working fluid, ammonium bicarbonate-water solutions appear very promising due to their capability to decompose at low temperature. In this work, an experimentally validated model for a reverse electrodialysis heat engine fed with ammonium bicarbonate-water solutions was developed. The model consists of two validated sub-models purposely integrated, one for the reverse electrodialysis unit and the other for the stripping/absorption regeneration uni…