126 research outputs found
Attentive monitoring of multiple video streams driven by a Bayesian foraging strategy
In this paper we shall consider the problem of deploying attention to subsets
of the video streams for collating the most relevant data and information of
interest related to a given task. We formalize this monitoring problem as a
foraging problem. We propose a probabilistic framework to model observer's
attentive behavior as the behavior of a forager. The forager, moment to moment,
focuses its attention on the most informative stream/camera, detects
interesting objects or activities, or switches to a more profitable stream. The
approach proposed here is suitable to be exploited for multi-stream video
summarization. Meanwhile, it can serve as a preliminary step for more
sophisticated video surveillance, e.g. activity and behavior analysis.
Experimental results achieved on the UCR Videoweb Activities Dataset, a
publicly available dataset, are presented to illustrate the utility of the
proposed technique.Comment: Accepted to IEEE Transactions on Image Processin
In vitro antitumor activity of water-soluble copper(I) complexes with diimine and monodentate phosphine ligands
Copper(I) complexes including diimine ligands of the bicinchoninic acid (BCA) and bathocuproinedisulfonic acid (BCS) families and water-soluble phosphines have been synthetized, characterized and investigated for their in vitro anticancer potential against human tumor cell lines representing examples of lung, breast, pancreatic and colon cancers and melanoma. All copper complexes exhibited moderate to high cytotoxic activity and the ability to overcome cisplatin resistance. Remarkably, growth-inhibitory effects evaluated in human non-transformed cells revealed a preferential cytotoxicity versus neoplastic cells. The remarkable cytotoxic effect towards BxPC3 pancreatic cancer cells, notoriously poor sensitive to cisplatin, was not related to a DNA or proteasome damage. Keywords: Copper(I) complexes, Antitumor activity, Diimine ligands, Phosphine ligands, Water solubl
Therapeutic potential of the phosphino Cu(I) complex (HydroCuP) in the treatment of solid tumors
[Cu(thp)4][PF6] (HydroCuP) is a phosphino copper(I) complex highly soluble and stable in physiological media that has been developed as a possible viable alternative to platinum-based drugs for anticancer therapy. HydroCuP potently inhibited the growth of human cancer cells derived from solid tumors by inducing endoplasmatic reticulum (ER) stress thus leading to cell death through paraptosis with a preferential efficacy against cancer rather than non-cancer cells. Aim of the present study was to assess the therapeutic potential of HydroCuP in vivo, in syngenic and xenograft murine models of solid tumors by triggering the Unfolded Protein Response (UPR) pathway. With respect to platinum drugs, HydroCuP induced a markedly higher reduction of tumor growth associated with minimal animal toxicity. In human colorectal cancer xenografts, chemotherapy with HydroCuP was extremely effective in both oxaliplatin-sensitive and resistant models. The favorable in vivo tolerability of HydroCuP was also correlated to an encouraging biodistribution profile. Additionally, no signs of drug-related neurotoxicity and nephrotoxicity were observed. Altogether, these results demonstrate that HydroCuP appears worth of further investigation to evaluate its therapeutic activity towards a broad spectrum of solid malignancies
Cu(i) and Ag(i) complex formation with the hydrophilic phosphine 1,3,5-triaza-7-phosphadamantane in different ionic media. How to estimate the effect of a complexing medium
The complexes of Cu(i) and Ag(i) with 1,3,5-triaza-7-phosphadamantane (PTA) are currently studied for their potential clinical use as anticancer agents, given the cytotoxicity they exhibited in vitro towards a panel of several human tumor cell lines. These metallodrugs are prepared in the form of [M(PTA)4]+ (M = Cu+, Ag+) compounds and dissolved in physiological solution for their administration. However, the nature of the species involved in the cytotoxic activity of the compounds is often unknown. In the present work, the thermodynamics of formation of the complexes of Cu(i) and Ag(i) with PTA in aqueous solution is investigated by means of potentiometric, spectrophotometric and microcalorimetric methods. The results show that both metal(i) ions form up to four successive complexes with PTA. The formation of Ag(i) complexes is studied at 298.15 K in 0.1 M NaNO3 whereas the formation of the Cu(i) one is studied in 1 M NaCl, where Cu(i) is stabilized by the formation of three successive chloro-complexes. Therefore, for this latter system, conditional stability constants and thermodynamic data are obtained. To estimate the affinity of Cu(i) for PTA in the absence of chloride, Density Functional Theory (DFT) calculations have been done to obtain the stoichiometry and the relative stability of the possible Cu/PTA/Cl species. Results indicate that one chloride ion is involved in the formation of the first two complexes of Cu(i) ([CuCl(PTA)] and [CuCl(PTA)2]) whereas it is absent in the successive ones ([Cu(PTA)3]+ and [Cu(PTA)4]+). The combination of DFT results and thermodynamic experimental data has been used to estimate the stability constants of the four [Cu(PTA)n]+ (n = 1-4) complexes in an ideal non-complexing medium. The calculated stability constants are higher than the corresponding conditional values and show that PTA prefers Cu(i) to the Ag(i) ion. The approach used here to estimate the hidden role of chloride on the conditional stability constants of Cu(i) complexes may be applied to any Cu(i)/ligand system, provided that the stoichiometry of the species in NaCl solution is known. The speciation for the two systems shows that the [M(PTA)4]+ (M = Cu+, Ag+) complexes present in the metallodrugs are dissociated into lower stoichiometry species when diluted to the micromolar concentration range, typical of the in vitro biological testing. Accordingly, [Cu(PTA)2]+, [Cu(PTA)3]+ and [Ag(PTA)2]+ are predicted to be the species actually involved in the cytotoxic activity of these compounds. \ua9 2017 The Royal Society of Chemistry
Phthalates and heavy metals as endocrine disruptors in food: A study on pre-packed coffee products
Phthalate plasticizers and heavy metals are widely recognized to be pollutants that interfere with key developmental processes such as masculinization. We investigated the release of phthalates and heavy metals in coffee brewed from coffee packed in single-serve coffee containers made from different types of materials: metal, biodegradable and plastics. We detected with GC\u2013MS small amounts phthalates, below the tolerated daily risks levels, in all the coffees prepared from the different types of capsules. Specifically, Di (2-ethyl-hexyl)-phthalate and DiBP: Diisobuthyl-pthalate were ubiquitously present despite the high variability among the samples (respective range 0.16\u20131.87 \u3bcg/mL and 0.01\u20130.36 \u3bcg/mL). Whereas, diethyl-phthalate (range 0.20\u20130.26 \u3bcg/mL) and di-n-buthyl-phthalate (range 0.02\u20130.14 \u3bcg/mL) were detected respectively in one and three out of the four types of capsule tested. In contrast, we detected by atomic mass spectrometry on mineralized samples heavy metals lead (Pb) and nickel (Ni), in all coffee tested. PB levels (respective range 0.32\u2013211.57 \u3bcg/dose) accounted for 42\u201379%, whereas Ni levels (respective range 166.25\u20131950.26 \u3bcg/dose) accounted for >100% of the tolerable daily intake. These results add to the already present concerns related to the multiple pathways of human exposure and the ubiquitous presence of these pollutants in consumer products and their long-term effect on human health
Evidence of noncovalent complexes in some natural extracts: Ceylon tea and mate extracts
AbstractConsidering the high complexity of natural extracts, because of the presence of organic molecules of different chemical nature, the possibility of formation of noncovalent complexes should be taken into account. In a previous investigation, the formation of bimolecular complexes between caffeine and catechins in green tea extracts (GTE) has been experimentally proven by means of mass spectrometric and 1H nuclear magnetic resonance experiments. The same approaches have been employed in the present study to evaluate the presence of bimolecular complexes in Ceylon tea and mate extracts. The obtained results show that in the case of Ceylon tea extracts, protonated theaflavin is detectable, together with theaflavin/caffein complexes, while caffeine/catechin complexes, already detected in green tea, are still present but at lower concentration. This aspect is evidenced by the comparison of precursor ion scans performed on protonated caffeine for the two extracts. The spectra obtained in these conditions for GTE and Ceylon tea show that the complexes of caffeine with epigallocatechin (EGC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG), highy abundant in the case of GTE (signalâtoâchemical noise ratio in the range 50â100), are negligible (signalâtoâchemical noise ratio in the range 2â3) in the case of Ceylon tea. Mate extracts show the formation of bimolecular complexes involving caffeine but not catechins, and chlorogenic acid becomes responsible for other complex formation. Under positive ion and negative ion conditions, accurate mass measurements allow the identification of malealdehyde, chlorogenic acid, caffeine, two isomers of dicaffeoylquinic acid, rutin, and kaempferolâ3âOârutinoside. These data indicate that the formation of complexes in natural extracts is a common behavior, and their presence must be considered in the description of natural extracts and, consequently, in their biological activity
Avaliação in vitro da atividade antileishmania de complexos de cobre (I)
In the research for the development of new drugs for the therapy of American tegumentary leishmaniasis, copper has been studied for its antileishmania activity. This study aims to report the activity of three copper(I) complexes on parasites of the species L. amazonensis and L. guyanensis. The metal complexes were tested according to in vitro antileishmanial assays, against promastigote and amastigote forms of the most prevalent species in the state of Amazonas, Brazil. Cytotoxicity of the complexes was evaluated in murine macrophage-like cell line (MJ774). The results of the in vitro assays indicated that, among the copper complexes tested, the homoleptic phosphine complex [Cu(thp)4][PF6](thp=tris-hydroxymethylphosphine) presented promising activity against the evolutionary forms of L. amazonensis, and obtained a IC50 of 26.45 and 24.61 ”M in a period of 48 and 72 h, respectively. The results for copper complex at concentration 160 ”M in amastigote forms showed a decrease in the infection index (32% of infected cells) and, in the cytotoxicity assay with MJ774, 52.43% of cell viability was observed. The results showed that the complex [Cu(thp)4][PF6] presented significant biological activity, indicating a need for future in vivo studies.Na busca do desenvolvimento de novos fĂĄrmacos para a terapia da leishmaniose tegumentar americana, o cobre tem sido estudado quanto a sua atividade antileishmania. Esse estudo tem como objetivo relatar a atividade de trĂȘs complexos de cobre (I) sobre parasitas das espĂ©cies L. amazonensis e L. guyanensis. Os complexos metĂĄlicos foram testados por meio de ensaios antileishmania in vitro contra as formas promastigota e amastigota das espĂ©cies mais prevalentes no estado do Amazonas, Brasil. A citotoxicidade dos complexos foi avaliada em linhagem de cĂ©lulas semelhantes a macrĂłfagos murinos (MJ774). Os resultados dos ensaios in vitro indicaram que, entre os complexos de cobre testados, o complexo homolĂ©ptico de fosfina [Cu(thp)4][PF6](thp=tris-hidroximetilfosfina) apresentou atividade promissora contra as formas evolutivas de L. amazonensis, e obtiveram IC50 de 26,45 e 24,61 ”M em um perĂodo de 48 e 72 h, respectivamente. Os resultados para o complexo de cobre na concentração de 160 ”M nas formas amastigotas reportaram diminuição no Ăndice de infecção (32% das cĂ©lulas infectadas) e, no ensaio de citotoxicidade com MJ774, observou-se 52,43% de viabilidade celular. Os resultados evidenciaram que o complexo [Cu(thp)4][PF6] apresentou atividade biolĂłgica significativa, indicando a necessidade de futuros estudos in vivo
Synthesis and structural characterization of new oxorhenium and oxotechnetium complexes with XN2S-tetradentate semi-rigid ligands(X = O, S, N)
Twelve novel oxo-technetium and oxo-rhenium complexes based on N2S2-, N2SO- or N3S-tetradentate semi-rigid
ligands have been synthesised and studied herein. By reacting the ligands with a slight excess of suitable [MO]3+
precursor (ReOCl3(PPh3)2 or [NBu4][99gTcOCl4]), the monoanionic complexes of general formula [MO(PhâXN2S)]â
could be easily produced in high yield. The complexes have been characterized by means of IR, electrospray mass
spectrometry, elemental analysis, NMR and conductimetry. The crystal structures of [PPh4][ReO(PhâON2S)] 1b and
[NBu4][99gTcO(PhâON2S)] 1c have been established. The [MO]3+ moiety was coordinated via the two deprotonated
amide nitrogens, the oxygen and the terminal sulfur atoms in 1b and 1c. In both compounds, the ON2S coordination
set is in the equatorial plane, and the complexes adopted a distorted square-pyramidal geometry with an axial
oxo-group. The chemical and structural identity of the different prototypic complexes (rhenium, 99gTc complexes and
their corresponding 99mTc radiocomplexes) have been also established by a comparative HPLC study
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