Malignant gliomas are a lethal type of brain tumors that poorly respond to chemotherapeutic drugs. Several therapy resistance mechanisms have been characterized. However, the response to stress ...through mRNA translational control has not been evaluated for this type of tumor. A potential target would involve the alpha subunit of eukaryotic translation initiation factor (eIF2α) that leads to assembly of stress granules (SG) which are cytoplasmic granules mainly composed by RNA binding proteins and untranslated mRNAs. We assessed whether glioma cells are capable of assembling SG after exposure to different classes of chemotherapeutic agents through evaluation of the effects of interfering in this process by impairing the eIF2α signaling. C6 and U87MG cells were exposed to bortezomib, cisplatin, or etoposide. Forced expression of a dominant negative mutant of eIF2α (eIF2α
DN
) was employed to block this pathway. We observed that exposure to drugs stimulated SG assembly. This was reduced in eIF2α
DN
-transfected cells and this strategy enhanced chemotherapeutically-induced cell death for all drugs. Our data suggest that SG assembly occurs in glioma cells in response to chemotherapeutic drugs in an eIF2α-dependent manner and this response is relevant for drug resistance. Interfering with eIF2α signaling pathway may be a potential strategy for new co-adjuvant therapies to treat gliomas.
A cold stellar stream in Pegasus Perottoni, Hélio D; Martin, Charles; Newberg, Heidi Jo ...
Monthly notices of the Royal Astronomical Society,
06/2019, Letnik:
486, Številka:
1
Journal Article
Abstract
We report on the discovery of
SPLUS J210428.01−004934.2
, an ultra metal-poor (UMP) star first identified from the narrowband photometry of the Southern Photometric Local Universe Survey ...(S-PLUS) Data Release 1, in the SDSS Stripe 82 region. Follow-up medium- and high-resolution spectroscopy (with Gemini South and Magellan-Clay, respectively) confirmed the effectiveness of the search for low-metallicity stars using the S-PLUS narrowband photometry. At Fe/H = −4.03,
SPLUS J2104−0049
has the lowest
detected
carbon abundance,
A
(C) = +4.34, when compared to the 34 previously known UMP stars in the literature, which is an important constraint on its stellar progenitor and also on stellar evolution models at the lowest metallicities. Based on its chemical abundance pattern, we speculate that
SPLUS J2104−0049
could be a bona fide second-generation star, formed from a gas cloud polluted by a single metal-free ∼ 30
M
⊙
star. This discovery opens the possibility of finding additional UMP stars directly from narrowband photometric surveys, a potentially powerful method to help complete the inventory of such peculiar objects in our Galaxy.
The appeal for more reliable, efficient and resilient power grids has become indispensable with the recent technological development and ever-increasing demand for electrical energy. These goals ...might be achieved by introducing sensors and actuators in the power grid, with the purpose of enabling a smart control of the power network. All power devices must be connected using a reliable communication network, which should be able to operate even when the power grid fails. Currently, several communication technologies have been applied for supporting this new application scenario. This article aims for reviewing both academic and market use cases for technologies applied to the mission-critical, control networks and Smart Grid applications, such as teleprotection, self-healing, communication with control centers and field devices, among others. More specifically, the key aspects, potential technologies, main protocols and use cases of operating data networks in energy transmission, power distribution and smart grid environments, including circuit and packet switching technologies, are discussed into details. Furthermore, resilience and the main telecommunications technologies used in power grids, as well, the correlation among them, are exploited in practical point of view. The article provides a broad discussion on the best telecommunication options to build the emerging intelligent energy distribution systems, covering control networks, teleprotection, and smart grid applications.
Abstract We present a comprehensive recalibration of narrowband/medium-band and broadband photometry from the Southern Photometric Local Universe Survey (S-PLUS) by leveraging two approaches: an ...improved Gaia XP synthetic photometry (XPSP) method with corrected Gaia XP spectra, and the stellar color regression (SCR) method with corrected Gaia Early Data Release 3 photometric data and spectroscopic data from LAMOST Data Release 7. Through the use of millions of stars as standards per band, we demonstrate the existence of position-dependent systematic errors, up to 23 mmag for the main survey region, in the S-PLUS iDR4 photometric data. A comparison between the XPSP and SCR methods reveals minor differences in zero-point offsets, typically within the range of 1–6 mmag, indicating the accuracy of the recalibration, and a twofold to threefold improvement in the zero-point precision. During this process, we also verify and correct for systematic errors related to CCD position. The corrected S-PLUS iDR4 photometric data will provide a solid data foundation for conducting scientific research that relies on high-precision calibration. Our results underscore the power of the XPSP method in combination with the SCR method, showcasing their effectiveness in enhancing calibration precision for wide-field surveys when combined with Gaia photometry and XP spectra, to be applied for other S-PLUS subsurveys.
Abstract
We report on a chemo-dynamical analysis of SPLUS J142445.34−254247.1 (SPLUS J1424−2542), an extremely metal-poor halo star enhanced in elements formed by the rapid neutron-capture process (
...r
-process). This star was first selected as a metal-poor candidate from its narrowband S-PLUS photometry and followed up spectroscopically in medium resolution with Gemini-South/GMOS, which confirmed its low-metallicity status. High-resolution spectroscopy was gathered with GHOST at Gemini-South, allowing for the determination of the chemical abundances for 36 elements, from carbon to thorium. At Fe/H = −3.39, SPLUS J1424−2542 is one of the lowest-metallicity stars with measured Th and has the highest
log
ϵ
(
Th
/
Eu
)
observed to date, making it part of the “actinide-boost” category of
r
-process–enhanced stars. The analysis presented here suggests that the gas cloud from which SPLUS J1424−2542 formed must have been enriched by at least two progenitor populations. The light-element (
Z
≤ 30) abundance pattern is consistent with the yields from a supernova explosion of metal-free stars with 11.3–13.4
M
⊙
, and the heavy-element (
Z
≥ 38) abundance pattern can be reproduced by the yields from a neutron star merger (1.66
M
⊙
and 1.27
M
⊙
) event. A kinematical analysis also reveals that SPLUS J1424−2542 is a low-mass, old halo star with a likely in situ origin, not associated with any known early merger events in the Milky Way.
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•Nitrooxy compound 1 (NC1) potentially releases nitric oxide.•Plasma nitrite concentration was increased after administration of NC1.•NC1 inhibited the tactile hypersensitivity and ...paw edema in mice.•NC1 reduced neutrophil recruitment and IL-6, IL-1β, TNF-α and CXCL-1 concentrations.•NC1 increased the production of IL-10.
Considering the many biological activities of nitric oxide (NO), some lines of research focused on the modulation of these activities through the provision of this mediator by designing and synthesizing compounds coupled with an NO donor group. Thus, the objectives of the present study were to carry out an electrochemical investigation of the nitrooxy compound 4-((nitrooxy) methyl)-3-nitrobenzoic acid (1) and evaluate its activities and putative mechanisms in experimental models of pain and inflammation. Voltammetric studies performed in aprotic medium (mimetic of membranes) showed important electrochemical reduction mechanisms: nitroaromatic reduction, self-protonation, and finally reductive elimination, which leads to nitrate release. Systemic administration of the nitrooxy compound (1) inhibited the nociceptive response induced by heat and the tactile hypersensitivity and paw edema induced by carrageenan in mice. The activities in the models of inflammatory pain and edema were associated with reduced neutrophil recruitment and production of inflammatory cytokines, such as interleukin (IL)-1β, IL-6, tumor necrosis factor-α and CXCL-1, and increased production of IL-10. Concluding, electrochemical analysis revealed unequivocally that electron transfer at the nitro group of the nitrooxy compound (1) results in the cleavage of the organic nitrate, potentially resulting in the generation of NO. This electrochemical mechanism may be compared to a biochemical electron-transfer mediated nitrate release that, by appropriate in vivo bioreduction (enzymatic or not) would lead to NO production. Compound (1) exhibits activities in models of inflammatory pain and edema that may be due to reduced recruitment of neutrophils and production of inflammatory cytokines and increased production of IL-10. These results reinforce the interest in the investigation of NO donor compounds as candidates for analgesic and anti-inflammatory drugs.
Aspidosperma pyrifolium
Mart. is an endemic plant from Brazilian northeastern, which is widely used in folk medicine to treat dermatitis, gastritis, and malaria due to its anti-inflammatory activity. ...Thus, the aim of this work was to characterize by analytical techniques
A. pyrifolium
in different particle sizes to use in the production of tea. For characterization, thermal analysis, optical microscopy, and near-infrared spectroscopy (NIR) techniques were used. After sieving, five samples, named AP01 (> 355 μm), AP02 (≥ 180 μm), AP03 (≥ 155 μm), AP04 (≥ 75 μm), and AP05 (≥ 38 μm), were obtained. Thermogravimetry curves showed three steps of decomposition, with different percentages of mass loss. The second step of decomposition showed the highest mass loss for the five samples. DTA curves of five samples showed a first endothermic peak at 91.70, 96.22, 96.29, 91.09, and 86.32 °C for AP01, AP02, AP03, AP04, and AP05, respectively. Decomposition of all particles occurred from 200 °C. The activation energy obtained through kinetic models showed significant differences between the two methodologies employed. NIR spectra were treated using chemometric tools, including principal component analysis and two PC were necessary to properly separate the samples. The analytical techniques used in this study allowed us to properly characterize the powders and could be used in the production of tea.
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•Surfactants are versatile assistant molecules for the key steps of biorefineries.•Surfactants enhance solubilization of lignin during pretreatments.•Hydrolysis of lignocellulosic ...biomass is improved by surfactant addition.•Surfactants promote enzyme stability and reduce enzyme dosage during hydrolysis.•Remaining surfactants from early biorefinery steps also enhance fermentation.
The use of lignocellulosic biomass (LCB) as feedstock has received increasing attention as an alternative to fossil-based refineries. Initial steps such as pretreatment and enzymatic hydrolysis are essential to breakdown the complex structure of LCB to make the sugar molecules available to obtain bioproducts by fermentation. However, these steps increase the cost of the bioproduct and often reduces its competitiveness against synthetic products. Currently, the use of surfactants has shown considerable potential to enhance lignocellulosic biomass processing. This review addresses the main mechanisms and role of surfactants as key molecules in various steps of biorefinery processes, viz., increasing the removal of lignin and hemicellulose during the pretreatments, increasing enzymatic stability and enhancing the accessibility of enzymes to the polymeric fractions, and improving the downstream process during fermentation. Further, technical advances, challenges in application of surfactants, and future perspectives to augment the production of several high value-added bioproducts have been discussed.
In Brazil, there are few descriptions in the literature on the angiographic pattern and clinical characteristics of young patients with acute coronary syndrome, despite the evident number of cases in ...the population. The objective of this study was to evaluate which clinical characteristics are most closely related to the acute coronary syndrome in young patients, and what long-term outcomes are in this population.
This is a prospective observational study with 268 patients aged under 55 years with acute coronary syndrome, carried out between May 2010 and May 2013. Data were obtained on demographics, laboratory test and angiography results, and the coronary treatment adopted. Statistical analysis was presented as percentages and absolute values.
Approximately 57% were men and the median age was 50 years (30 to 55). The main risk factors were arterial hypertension (68%), smoking (67%), and dyslipidemia (43%). Typical pain was present in 90% of patients. In young individuals, 25.7% showed ST segment elevation. Approximately 56.5% of patients presented with a single-vessel angiographic pattern. About 7.1% were submitted to coronary bypass surgery, and 42.1% to percutaneous coronary angioplasty. Intrahospital mortality was 1.5%, and the combined event rate (cerebrovascular accident/stroke, cardiogenic shock, reinfarction, and arrhythmias) was 13.8%. After a mean follow-up of 10 months, mortality was 9.8%, while 25.4% of the patients had new ischemic events, and 37.3% required readmission to hospital.
In the short-term, young patients presented with mortality rates below what was expected when compared to the rates noted in other studies. However, there was a significant increase in the number of events in the 10-month follow-up.
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