We present a comprehensive study of the nonproportionality of NaI(Tl) scintillation detectors within the context of dark matter search experiments. Our investigation, which integrates COSINE-100 data ...with supplementary
γ
spectroscopy, measures light yields across diverse energy levels from full-energy
γ
peaks produced by the decays of various isotopes. These
γ
peaks of interest were produced by decays supported by both long and short-lived isotopes. Analyzing peaks from decays supported only by short-lived isotopes presented a unique challenge due to their limited statistics and overlapping energies, which was overcome by long-term data collection and a time-dependent analysis. A key achievement is the direct measurement of the 0.87 keV light yield, resulting from the cascade following electron capture decay of
22
Na
from internal contamination. This measurement, previously accessible only indirectly, deepens our understanding of NaI(Tl) scintillator behavior in the region of interest for dark matter searches. This study holds substantial implications for background modeling and the interpretation of dark matter signals in NaI(Tl) experiments.
Fall armyworm (FAW), Spodoptera frugiperda, is one of the most destructive pests of maize in warm regions of the Americas and a severe invasive species in Africa. Considering the armyworm management ...and its ability to develop resistance rapidly to synthetic insecticides and Bacillus thuringiensis (Bt) toxins, we assessed the response of field and laboratory populations of FAW to Bt maize hybrids and Bt-based bioinsecticides. In the laboratory, FAW neonates from two Bt-resistant colonies and three field-collected populations were fed foliage of Bt maize or Bt bioinsecticides incorporated into artificial diet, and larval survival and biomass were recorded after seven days. Larvae of the two laboratory colonies resistant to Bt maize producing Cry1 or Cry2 toxins had high larval survival rates on foliage of specific Bt maize hybrids (i.e., Cry1F or Cry1A.105 + Cry2Ab). On foliage of the Cry1A.105 + Cry2Ab Bt maize, larvae of one of the field-collected populations had survival rates similar to the Bt-resistant laboratory larvae but had strong growth inhibition. The field-collected larvae had less than 30% survival on foliage of Cry1F maize and larval weights equivalent to those of the Cry1F-resistant colony. In addition, while some larvae survived exposure to formulations of B. thuringiensis kurstaki (i.e., Dipel and Thuricide), the two formulations of B. thuringiensis aizawai (i.e., Agree and Xentari) caused 100% larval mortality in all FAW colonies and the field populations, including the ones showing reduced-susceptibility to Cry1F or Cry1A.105 + Cry2Ab Bt maize. This research shows that there are field populations of FAW with different levels of susceptibility to specific Bt toxins and that resistance to Cry1 and/or Cry2 may or may not reduce the efficacy of certain Bt bioinsecticides against the neonates.
•Field-collected FAW varied in survival/growth on Cry1F or Cry1A.105 + Cry2Ab Bt maize.•Bt aizawai killed all larvae in all FAW populations while Bt kurstaki did not.•Cry-toxin resistance may reduce the efficacy of certain Bt bioinsecticides against FAW.
The combination of pharmacophoric nuclei with different targets has been a strategy for the development of new drugs aimed at improving cancer treatment. A series of ten novel ...phthalimido-thiazolidine-2-4-dione derivatives were synthesized by two different synthetic routes. The compounds were tested and evaluated in vitro, through antineoplastic activities against cancer cells. Cell cycle analysis and clonogenic assay were also performed. The synthesized FT-12 compound (9j) exhibited antiproliferative activity against Panc-1, Sk-mel-28, and PC-3 cells. FT-12 reduced the ability to form new clones, also caused irreversibility in cell cycle, inducing arrest in the S phase. Besides, the compound (FT-12) induced necrosis and apoptosis. The results suggest that phthalimido-thiazolidine derivatives may be useful in cancer therapy, highlighting compound FT-12 (9j) as a promising candidate. However, more studies must be carried out to confirm its viability.
We report the identification of metastable isomeric states of
228
Ac at 6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These states are produced by the
β
-decay of
228
Ra, a ...component of the
232
Th decay chain, with
β
Q-values of 39.52 keV, 39.13 keV and 25.61 keV, respectively. Due to the low Q-value of
228
Ra as well as the relative abundance of
232
Th and their progeny in low background experiments, these observations potentially impact the low-energy background modeling of dark matter search experiments.
Tropical forests are being deforested worldwide, and the remaining fragments are suffering from biomass and biodiversity erosion. Quantifying this erosion is challenging because ground data on ...tropical biodiversity and biomass are often sparse. Here, we use an unprecedented dataset of 1819 field surveys covering the entire Atlantic Forest biodiversity hotspot. We show that 83-85% of the surveys presented losses in forest biomass and tree species richness, functional traits, and conservation value. On average, forest fragments have 25-32% less biomass, 23-31% fewer species, and 33, 36, and 42% fewer individuals of late-successional, large-seeded, and endemic species, respectively. Biodiversity and biomass erosion are lower inside strictly protected conservation units, particularly in large ones. We estimate that biomass erosion across the Atlantic Forest remnants is equivalent to the loss of 55-70 thousand km
of forests or US$2.3-2.6 billion in carbon credits. These figures have direct implications on mechanisms of climate change mitigation.
Abstract We report the identification of metastable isomeric states of $$^{228}$$ 228 Ac at 6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These states are produced by the ...$$\beta $$ β -decay of $$^{228}$$ 228 Ra, a component of the $$^{232}$$ 232 Th decay chain, with $$\beta $$ β Q-values of 39.52 keV, 39.13 keV and 25.61 keV, respectively. Due to the low Q-value of $$^{228}$$ 228 Ra as well as the relative abundance of $$^{232}$$ 232 Th and their progeny in low background experiments, these observations potentially impact the low-energy background modeling of dark matter search experiments.
Cancer has become one of the leading causes of morbidity and mortality worldwide. Limitations associated with existing agents increase the need to develop more effective anticancer drugs to improve ...the therapeutic arsenal available. The aim of this study was to synthesize and evaluate the antiproliferative effects of three new thiazacridine derivatives.
Using a three steps synthesis reaction, three novel thiazacridine derivatives were obtained and characterized: (Z)-5-acridin-9-ylmethylene-3-(4-methyl-benzyl)-4-thioxo-thiazolidin- 2-one (LPSF/AC-99), (Z)-5-acridin-9-ylmethylene-3-(4-chloro-benzyl)-4-thioxo-thiazolidin-2- one (LPSF/AC-119) and (Z)-5-acridin-9-ylmethylene-3-(3-chloro-benzyl)-4-thioxo-thiazolidin-2- one (LPSF/AC-129). Toxicity and selectivity assays were performed by colorimetric assay. Then, changes in cell cycle and cell death induction mechanisms were assessed by flow cytometry.
All compounds exhibited cytotoxicity to Raji (Burkitt's lymphoma) and Jurkat (acute T cell leukemia) cells, where LPSF/AC-119 showed best IC50 values (0.6 and 1.53 µ M, respectively). LPSF/AC-129 was the only cytotoxic compound in glioblastoma cell line NG97 (IC50 = 55.77 µ M). None of the compounds were toxic to normal human cells and induced neoplastic cell death primarily by apoptosis.
All derivatives were more cytotoxic to hematopoietic neoplastic cells when compared to solid tumor derived cells. All three compounds are promising for in vivo and combination therapy studies against cancer.
Thiazacridine derivatives (ATZD) are a novel class of cytotoxic agents that combine an acridine and thiazolidine nucleus. In this study, the cytotoxic action of four ATZD were tested in human colon ...carcinoma HCT-8 cells: (5Z)-5-acridin-9-ylmethylene-3-(4-methylbenzyl)-thiazolidine-2,4-dione — AC-4; (5ZE)-5-acridin-9-ylmethylene-3-(4-bromo-benzyl)-thiazolidine-2,4-dione — AC-7; (5Z)-5-(acridin-9-ylmethylene)-3-(4-chloro-benzyl)-1,3-thiazolidine-2,4-dione — AC-10; and (5ZE)-5-(acridin-9-ylmethylene)-3-(4-fluoro-benzyl)-1,3-thiazolidine-2,4-dione — AC-23. All of the ATZD tested reduced the proliferation of HCT-8 cells in a concentration- and time-dependent manner. There were significant increases in internucleosomal DNA fragmentation without affecting membrane integrity. For morphological analyses, hematoxylin–eosin and acridine orange/ethidium bromide were used to stain HCT-8 cells treated with ATZD, which presented the typical hallmarks of apoptosis. ATZD also induced mitochondrial depolarisation and phosphatidylserine exposure and increased the activation of caspases 3/7 in HCT-8 cells, suggesting that this apoptotic cell death was caspase-dependent. In an assay using Saccharomyces cerevisiae mutants with defects in DNA topoisomerases 1 and 3, the ATZD showed enhanced activity, suggesting an interaction between ATZD and DNA topoisomerase enzyme activity. In addition, ATZD inhibited DNA topoisomerase I action in a cell-free system. Interestingly, these ATZD did not cause genotoxicity or inhibit the telomerase activity in human lymphocyte cultures at the experimental levels tested. In conclusion, the ATZD inhibited the DNA topoisomerase I activity and induced tumour cell death through apoptotic pathways.
► Thiazacridine derivatives induce mitochondrial-dependent apoptotic cell death. ► Thiazacridine derivatives inhibit DNA topoisomerase I action. ► Thiazacridine derivatives failed to cause genotoxicity on human lymphocytes.
•A label-free flexible biodevice applicable to COVID-19 was developed.•Flexible transducers were modified with polypyrrole films and gold nanoparticles.•The sensor showed a limit of detection of ...258.01 copies µL−1 with high selectivity.•The resistance variation was associated with the cycle threshold value of RT-PCR.•SARS-CoV-2 diagnosis was correlated with various stages of the viral infection.
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The projection of new biosensing technologies for genetic identification of SARS-COV-2 is essential in the face of a pandemic scenario. For this reason, the current research aims to develop a label-free flexible biodevice applicable to COVID-19. A nanostructured platform made of polypyrrole (PPy) and gold nanoparticles (GNP) was designed for interfacing the electrochemical signal in miniaturized electrodes of tin-doped indium oxide (ITO). Oligonucleotide primer was chemically immobilized on the flexible transducers for the biorecognition of the nucleocapsid protein (N) gene. Methodological protocols based on cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and atomic force microscopy (AFM) were used to characterize the nanotechnological apparatus. The biosensor’s electrochemical performance was evaluated using the SARS-CoV-2 genome and biological samples of cDNA from patients infected with retrovirus at various disease stages. It is inferred that the analytical tool was able to distinguish the expression of SARS-CoV-2 in patients diagnosed with COVID-19 in the early, intermediate and late stages. The biosensor exhibited high selectivity by not recognizing the biological target in samples from patients not infected with SARS-CoV-2. The proposed sensor obtained a linear response range estimated from 800 to 4000 copies µL−1 with a regression coefficient of 0.99, and a detection limit of 258.01 copies µL−1. Therefore, the electrochemical biosensor based on flexible electrode technology represents a promising trend for sensitive molecular analysis of etiologic agent with fast and simple operationalization. In addition to early genetic diagnosis, the biomolecular assay may help to monitor the progression of COVID-19 infection in a novel manner.
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