1,044 research outputs found
High strain rate behavior of aluminum die cast components
Abstract Research results of static and dynamic mechanical tests (É = 1 * 10-3 s-1 and É ~ 5 * 102 s-1 conducted on samples obtained from three different die cast products (component A, B and C) of AlSi10MnMg alloy are reported. All the components have thin-walled geometry except some thicker positions of component C. The dynamic (high strain rate) mechanical characterization shows an increase of tensile properties, in respect to static tensile ones (tensile strength increases approximately 15%, and the yield strength 30%, for all the die cast components) together with an evident plastic deformation, with consequent necked region in the fractured section, substantially negligible in case of static tensile tests. Moreover, fractographic observations are conducted on specimens undergone static and high strain rate test conditions, to observe the fracture morphology, together with metallographic analysis on the only polished or etched transverse specimens to reveal the porosity, and the microstructure of dendrite and inter-dendrite morphologies
Metal-based compounds containing selenium: An appealing approach towards novel therapeutic drugs with anticancer and antimicrobial effects
In recent years, both metal-based complexes and selenium-containing compounds have been widely explored for
their therapeutic properties due to their roles in biological processes and modulation of diverse molecular tar-
gets. However, despite their growing interest, there is no review to date that covers the potential use of the
combination of these entities to design new therapeutic derivatives. This review highlights the latest achieve-
ments in this particular field, with a focus on compounds with anticancer and/or antimicrobial properties. With
this aim, the formation of coordination compounds including several metals bearing selenium either with direct
interaction with the metal center or as part of the organic ligand elsewhere is covered. Besides, coordination
compounds with a Se(IV) center have been assessed. The biological properties of several selenium-containing
organometallic complexes have also been discussed, including metallocenes, half-sandwich complexes, and
compounds with N-heterocyclic carbenes, CO, and Ï-ligands, and other Ï-bonded entities. The information
compiled in this review may be helpful to design and develop novel, more potent, and safer metal-based com-
pounds for the treatment of several pathologies
Small molecules containing chalcogen elements (S, Se, Te) as new warhead to fight neglected tropical diseases
Neglected tropical diseases (NTDs) encompass a group of infectious diseases with a protozoan etiology, high
incidence, and prevalence in developing countries. As a result, economic factors constitute one of the main
obstacles to their management. Endemic countries have high levels of poverty, deprivation and marginalization
which affect patients and limit their access to proper medical care. As a matter of fact, statistics remain un-
collected in some affected areas due to non-reporting cases. World Health Organization and other organizations
proposed a plan for the eradication and control of the vector, although many of these plans were halted by the
COVID-19 pandemic. Despite of the available drugs to treat these pathologies, it exists a lack of effectiveness
against several parasite strains. Treatment protocols for diseases such as American trypanosomiasis (Chagas
disease), leishmaniasis, and human African trypanosomiasis (HAT) have not achieved the desired results. Un-
fortunately, these drugs present limitations such as side effects, toxicity, teratogenicity, renal, and hepatic
impairment, as well as high costs that have hindered the control and eradication of these diseases. This review
focuses on the analysis of a collection of scientific shreds of evidence with the aim of identifying novel chalcogen-
derived molecules with biological activity against Chagas disease, leishmaniasis and HAT. Compounds illustrated
in each figure share the distinction of containing at least one chalcogen element. Sulfur (S), selenium (Se), and
tellurium (Te) have been grouped and analyzed in accordance with their design strategy, chemical synthesis
process and biological activity. After an exhaustive revision of the related literature on S, Se, and Te compounds,
183 compounds presenting excellent biological performance were gathered against the different causative agents
of CD, leishmaniasis and HAT
M13 phages uptake of gold nanoparticles for radio-and thermal-therapy and contrast imaging improvement
The presented work deals with the uptake of gold nanoparticles (Au NPs) by M13 phages in solutions. In particular, the Au NPs uptake modalities and their localization in the filamentous phages are evaluated and measured. Gold spherical nanoparticles (with an average diameter of the order of 10 nm) are obtained by laser ablation in water with a sodium citrated surfactant. The interest of such application comes from the possibility to employ living biological structures to transport heavy metallic nanoparticles inside cells of tumoral tissues. Indeed, phages have the capability to introduce Au NPs in the proximity to the cell nucleus, increasing the efficiency of DNA destruction in the tumoral cells by employing low doses of ionizing radiation during radiotherapy and hyperthermia treatments. Several analyses and microscopy characterizations of the prepared phages samples embedding gold nanoparticles are presented, demonstrating that the presence of Au NPs increases the phages imaging contrast
Design, synthesis and anticancer evaluation of novel Se-NSAID hybrid molecules: Identification of a Se-indomethacin analog as a potential therapeutic for breast cancer
A total of twenty-five novel carboxylic acid, methylester, methylamide or cyano nonsteroidal anti-inflammatory
drug (NSAID) derivatives incorporating Se in the chemical form of selenoester were reported. Twenty Se-NSAID
analogs exhibited an increase in cytotoxic potency compared with parent NSAID scaffolds (aspirin, salicylic acid,
naproxen, indomethacin and ketoprofen). Top five analogs were selected to further study their cytotoxicity in a
larger panel of cancer cells and were also submitted to the DTP program of the NCIâs panel of 60 cancer cell lines.
Compounds 4a and 4d stood out with IC50 values below 10 ÎŒM in several cancer cells along with a selectivity
index higher than 5 in breast cancer cells. Remarkably, analog 4d was found to inhibit cell growth notably in two
breast cancer cell lines by inducing apoptosis, and to be metabolized to release the parent NSAID along with the
Se fragment. Taken together, our results show that Se-NSAID analog 4d could be a potential chemotherapeutic
drug for breast cancer
A diphenyldiselenide derivative induces autophagy via JNK in HTB-54 lung cancer cells
Symmetric aromatic diselenides are potential anticancer agents with strong cytotoxic activity. In this study, the in vitro anticancer activities of a novel series of diarylseleno derivatives from the diphenyldiselenide (DPDS) scaffold were evaluated. Most of the compounds exhibited high efficacy for inducing cytotoxicity against different human cancer cell lines. DPDS 2, the compound with the lowest mean GI50 value, induced both caspase-dependent apoptosis and arrest at the G0/G1 phase in acute lymphoblastic leucemia CCRF-CEM cells. Consistent with this, PARP cleavage; enhanced caspase-2, -3, -8 and -9 activity; reduced CDK4 expression and increased levels of p53 were detected in these cells upon DPDS 2 treatment. Mutated p53 expressed in CCRF-CEM cells retains its transactivating activity. Therefore, increased levels of p21CIP1 and BAX proteins were also detected. On the other hand, DPDS 6, the compound with the highest selectivity index for cancer cells, resulted in G2/M cell cycle arrest and caspase-independent cell death in p53 deficient HTB-54 lung cancer cells. Autophagy inhibitors 3-methyladenine, wortmannin and chloroquine inhibited DPDS 6-induced cell death. Consistent with autophagy, increased LC3-II and decreased SQSTM1/p62 levels were detected in HTB-54 cells in response to DPDS 6. Induction of JNK phosphorylation and a reduction in phospho-p38 MAPK were also detected. Moreover, the JNK inhibitor SP600125-protected HTB-54 cells from DPDS 6-induced cell death indicating that JNK activation is involved in DPDS 6-induced autophagy. These results highlight the anticancer effects of these derivatives and warrant future studies examining their clinical potential
CP--odd Correlation in the Decay of Neutral Higgs Boson into , , or
We investigate the possibility of detecting CP--odd angular correlations in
the various decay modes of the neutral Higgs boson including the modes of a
pair, a pair, or a heavy quark pair. It is a natural way to probe
the CP character of the Higgs boson once it is identified. Final state
interactions (i.e. the absorptive decay amplitude) is not required in such
correlations. As an illustrative example we take the fundamental source of the
CP nonconservation to be in the Yukawa couplings of the Higgs boson to the
heavy fermions. A similar correlation in the process is
also proposed. Our analysis of these correlations will be useful for
experiments in future colliders such as LEP II, SSC, LHC or NLC.Comment: 16 pages, plus 8 postscript graphs not posted befor
Novel N,N' -Disubstituted Acylselenoureas as Potential Antioxidant and Cytotoxic Agents
Selenium compounds are pivotal in medicinal chemistry for their antitumoral and
antioxidant properties. Forty seven acylselenoureas have been designed and synthesized following
a fragment-based approach. Different scaffolds, including carbo- and hetero-cycles, along with
mono- and bi-cyclic moieties, have been linked to the selenium containing skeleton. The doseand time-dependent radical scavenging activity for all of the compounds were assessed using the
in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,20
-azino-bis(3-ethylbenzthiazoline-6-sulfonic
acid) (ABTS) assays. Some of them showed a greater radical scavenging capacity at low doses and
shorter times than ascorbic acid. Therefore, four compounds were evaluated to test their protective
effects against H2O2-induced oxidative stress. One derivative protected cells against H2O2-induced
damage, increasing cell survival by up to 3.6-fold. Additionally, in vitro cytotoxic activity of all
compounds was screened against several cancer cells. Eight compounds were selected to determine
their half maximal inhibitory concentration (IC50) values towards breast and lung cancer cells, along
with their selectivity indexes. The breast cancer cells turned out to be much more sensitive than the
lung. Two compounds (5d and 10a) stood out with IC50 values between 4.2 ”M and 8.0 ”M towards
MCF-7 and T47D cells, with selectivity indexes greater than 22.9. In addition, compound 10b exhibited
dual antioxidant and cytotoxic activities. Although further evidence is needed, the acylselenourea
scaffold could be a feasible frame to develop new dual agents
Recommended from our members
Invasiveness of the Yersinia pestis ail protein contributes to host dissemination in pneumonic and oral plague
Yersinia pestis, a Gram-negative bacterium, is the etiologic agent of plague. A hallmark of Y. pestis infection is the organism's ability to rapidly disseminate through an animal host. Y. pestis expresses the outer membrane protein, Ail (Attachment invasion locus), which is associated with host invasion and serum resistance. However, whether Ail plays a role in host dissemination remains unclear. In this study, C57BL/6J mice were challenged with a defined Y. pestis strain, KimD27, or an isogenic ail-deleted mutant derived from KimD27 via metacarpal paw pad inoculation, nasal drops, orogastric infection, or tail vein injection to mimic bubonic, pneumonic, oral, or septicemic plague, respectively. Our results showed that ail-deleted Y. pestis KimD27 lost the ability to invade host cells, leading to failed host dissemination in the pneumonic and oral plague models but not in the bubonic or septicemic plague models, which do not require invasiveness. Therefore, this study demonstrated that whether Ail plays a role in Y. pestis pathogenesis depends on the infection route.Peer reviewe
- âŠ