Showing papers by "National Nuclear Energy Commission published in 2021"

Comparison of foliar spray and soil irrigation of biogenic CuO nanoparticles (NPs) on elemental uptake and accumulation in lettuce.

Abstract: Nanoparticles (NPs) can be used in several ways in agriculture, including increasing production rates and improving nutritional values in plants. The present study aims to clarify how biogenic copper oxide nanoparticles (CuO NPs) applied by two routes of exposure (foliar spray and soil irrigation) affect the elemental uptake by lettuce. In vivo experiments using lettuce (n = 4) were performed with CuO NPs in comparison with copper salt (CuSO4), considering a final mass added of 20 mg of CuO per plant. The elemental composition of roots was mostly affected by the soil irrigation exposure for both Cu forms (NPs and salt). Neither Cu form added by soil irrigation was translocated to leaves. Copper concentration in leaves was mainly affected by foliar spray exposure for both Cu forms (NPs and salt). All Cu forms through foliar spray were sequestered in the leaves and no translocation to roots was observed. Foliar spray of CuO NPs caused no visual damage in leaves, resulted in less disturbance of elemental composition, and improved dry weight, number of leaves, CO2 assimilation, and the levels of K, Na, S, Ag, Cd, Cr, Cu, and Zn in leaves without causing significant changes in daily intake of most elements, except for Cu. Although Cu concentration increased in leaves by foliar spray of CuO NPs, it remained safe for consumption.

Water-Soluble Chitosan Conjugated DOTA-Bombesin Peptide Capped Gold Nanoparticles as a Targeted Therapeutic Agent for Prostate Cancer

Abstract: Introduction Functionalization of water-soluble chitosan (WSCS) nanocolloids with, gold nanoparticles (AuNPs), and LyslLys3 (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-bombesin 1-14 (DOTA-BBN) peptide affords an innovative pathway to produce prostate tumor cell-specific nanomedicine agents with potential applications in molecular imaging and therapy. Methods The preparation involves the production and full characterization of water-soluble chitosan (WSCS), via gamma (γ) rays (80 kGy) irradiation, followed by DOTA-BBN conjugation for subsequent use as an effective template toward the synthesis of tumor cell-specific AuNPs-WSCS-DOTA-BBN. Results The WSCS-DOTA-BBN polymeric nanoparticles (86 ± 2.03 nm) served multiple roles as reducing and stabilizing agents in the overall template synthesis of tumor cell-targeted AuNPs. The AuNPs capped with WSCS and WSCS-DOTA-BBN exhibited average Au-core diameter of 17 ± 8 nm and 20 ± 7 nm with hydrodynamic diameters of 56 ± 1 and 67± 2 nm, respectively. The AuNPs-WSCS-DOTA-BBN showed optimum in vitro stability in biologically relevant solutions. The targeted AuNPs showed selective affinity toward GRP receptors overexpressed in prostate cancer cells (PC-3 and LNCaP). Discussion The AuNPs-WSCS-DOTA-BBN displayed cytotoxicity effects against PC-3 and LNCaP cancer cells, with concomitant safety toward the HAECs normal cells. The AuNPs-WSCS-DOTA-BBN showed synergistic targeting toward tumor cells with selective cytotoxicity of AuNPs towards PC-3 and LNCaP cells. Our investigations provide compelling evidence that AuNPs functionalized with WSCS-DOTA-BBN is an innovative nanomedicine approach for use in molecular imaging and therapy of GRP receptor-positive tumors. The template synthesis of AuNPs-WSCS-DOTA-BBN serves as an excellent non-radioactive surrogate for the development of the corresponding 198AuNPs theragnostic nanoradiopharmaceutical for use in cancer diagnosis and therapy.

Green nanotechnology of MGF-AuNPs for immunomodulatory intervention in prostate cancer therapy.

Abstract: Men with castration-resistant prostate cancer (CRPC) face poor prognosis and increased risk of treatment-incurred adverse effects resulting in one of the highest mortalities among patient population globally. Immune cells act as double-edged sword depending on the tumor microenvironment, which leads to increased infiltration of pro-tumor (M2) macrophages. Development of new immunomodulatory therapeutic agents capable of targeting the tumor microenvironment, and hence orchestrating the transformation of pro-tumor M2 macrophages to anti-tumor M1, would substantially improve treatment outcomes of CRPC patients. We report, herein, Mangiferin functionalized gold nanoparticulate agent (MGF-AuNPs) and its immunomodulatory characteristics in treating prostate cancer. We provide evidence of immunomodulatory intervention of MGF-AuNPs in prostate cancers through observations of enhanced levels of anti-tumor cytokines (IL-12 and TNF-α) with concomitant reductions in the levels of pro-tumor cytokines (IL-10 and IL-6). In the MGF-AuNPs treated groups, IL-12 was elevated to ten-fold while TNF-α was elevated to about 50-fold, while IL-10 and IL-6 were reduced by two-fold. Ability of MGF-AuNPs to target splenic macrophages is invoked via targeting of NF-kB signaling pathway. Finally, therapeutic efficacy of MGF-AuNPs, in treating prostate cancer in vivo in tumor bearing mice, is described taking into consideration various immunomodulatory interventions triggered by this green nanotechnology-based nanomedicine agent.

Methane conversion to higher value-added product and energy co-generation using anodes OF PdCu/C in a solid electrolyte reactor: alkaline fuel cell type monitored by differential mass spectroscopy

Abstract: PdxCuy/C catalysts combinations were employed to CH4 partial oxidation in mild condition using a solid electrolyte reactor—alkaline fuel cell type. The differential mass spectroscopy on line method was used to monitor the oxidation products obtained as methanol, dimethyl ether, methyl formate and potassium formate. It was observed that as the electrical potential of the reactor increases, the generation of products decreases. The best results for conversion of methane into methanol and energy co-generation was obtained from Pd90Cu10/C and Pd50Cu50/C due to better H2O activation effects and adsorption site for CH4 oxidation.

(INVITED) JOYSpectra: A web platform for luminescence of lanthanides

Abstract: JOYSpectra is a free-of-charge web platform to perform online calculations of spectroscopic properties of lanthanide-based compounds and materials. It has several features and functionalities to provide a detailed analysis of the intensity parameters. For instance, their dependence on the chemical environment of the lanthanide ion (Ln3+) such as structure and nature of ligating atoms, can be performed automatically and consider covalency and thermal effects. The program can also calculate the intramolecular energy transfer rates from excited donor states up to 310 transitions involving 12 Ln3+ ions. The web platform was designed to be user-friendly for experimentalists and theoreticians interested in calculations and analyses of the photophysical behavior of lanthanides. Its use requires only the structure of the compound and the choices of a few calculation options. To show its easiness and usefulness, a detailed step-by-step calculation and analysis are performed for the [Ln(tta)3(H2O)2] (Ln: Eu and Tb) complexes to explain and quantify their distinct luminescence properties.

A Constrained Analysis of the 40Ca(18O,18F)40K Direct Charge Exchange Reaction Mechanism at 275 MeV

Abstract: The 40Ca(18O,18F)40K single charge exchange (SCE) reaction is explored at 275 MeV incident energy and analyzed consistently with elastic and inelastic scattering data collected in the same experimental conditions. Fully quantum mechanical SCE calculations of the direct mechanism are performed including microscopic nuclear structure inputs and adopting either a bare optical potential or a coupled channel equivalent polarization potential constrained by elastic and inelastic data. The direct SCE mechanism describes magnitude and shape of the angular distributions rather well, thus suggesting the suppression of sequential multi-nucleon transfer processes.

Recent Advances in Brachytherapy Using Radioactive Nanoparticles: An Alternative to Seed-Based Brachytherapy

Abstract: Interstitial brachytherapy (BT) is generally used for the treatment of well confined solid tumors. One example of this is treatment of the prostate tumors by permanent placement of radioactive seeds within the prostate gland, where low doses of radiation are delivered for several months. However, successful implementation of this technique is hampered due to several post treatment adverse effects or symptoms and operational and logistical complications associated to it. Recently, with the advancements in nanotechnology, radioactive nanoparticles (radio-NPs) functionalized with tumor specific biomolecules, injected intratumorally, has been reported as an alternative to seed based BT. Successful treatment of solid tumors using radio-NPs has been reported in several preclinical studies, on both mice and canine models. In this article we review the recent advancements in the synthesis and use of radio-NPs as a substitute to seed based BT. Here we discuss the limitations of current seed based BT and advantages of radio-NPs for brachytherapy applications. Recent progress on the types of radio-NPs, their features, synthesis methods and delivery techniques are discussed. The last part of the review focuses on the currently used dosimetry protocols and studies on the dosimetry of nanobrachytherapy applications using radio-NPs. The current challenges and future research directions on the role of radio-NPs in brachytherapy treatments are​ also discussed.

Employing resilience engineering in eliciting software requirements for complex systems: experiments with the functional resonance analysis method (FRAM)

Abstract: Resilience engineering provides concepts and methods for assessing the ability of socio-technical systems to adjust their functioning before, during, or after changes or disturbances. As such, this field of study has great potential to contribute to software engineering—particularly for the requirements specification for information systems—that deals with variability, unpredictability, and adaptation in complex contexts. Despite software engineers’ efforts, the requirements phase is still challenging, especially in complex socio-technical systems. In these systems, the software must be more resilient and adaptable to deal with uncertain situations. Thus, this study aimed to investigate the contributions of resilience engineering to requirements engineering to identify software requirements for complex systems. Two experiments were performed with software professionals to produce requirements specifications in healthcare. The participants used information from the functional resonance analysis method (FRAM) compared to business process modeling notation (BPMN). Both experiments were supported by a systematic approach called MacKnight. This study indicates innovative strategies to gather resilient software requirements from FRAM models for complex systems.

Multiple adverse effects of textile effluents and reactive Red 239 dye to aquatic organisms.

Abstract: Textile dyeing consumes high volumes of water, generating proportional number of colored effluents which contain several hazardous chemical. These contaminants can implicate in significant changes in aquatic environmental, including several adverse effects to organisms in different trophic levels. The present study was developed to assess the ecotoxicological effects of textile effluent samples and reactive Red 239 dye (used in cotton dyeing) to aquatic organisms Vibrio fischeri bacteria, Daphnia similis crustacean, and Biomphalaria glabrata snail (adults and embryos). Chronic assays with lethal and sublethal effects for Daphnia similis were included and performed only for textile effluents samples. The mutagenicity was also evaluated with Salmonella/microsome assay (TA98, TA100, and YG1041 strains). V. fischeri bacteria was the most sensitive to reactive Red 239 dye (EC50 = 10.14 mg L−1) followed by mollusk embryos at all stages (EC50 = 116.41 to 124.14 mg L−1), D. similis (EC50= 389.42 mg L−1), and less sensitive to adult snails (LC50= 517.19 mg L−1). The textile effluent was toxic for all exposed organisms [E(L)C50 < 15%] and B. glabrata embryos showed different responses in the early stages of blastulae and gastrulae (EC50 = 7.60 and 7.08%) compared to advanced development stages trochophore and veliger (EC50 = 21.56 and 29.32%). Developmental and sublethal effects in B. glabrata embryos and D. similis were evidenced. In the chronic assay with effluent, the EC10/NOEC = 3% was obtained. Mutagenic effects were not detected for dye aqueous solutions neither for effluents samples. These data confirmed the importance of evaluating the effects in aquatic organisms from different trophic levels and reinforce the need for environmental aquatic protection.

Community health workers' attitudes, practices and perceptions towards the COVID-19 pandemic in brazilian low-income communities.

Abstract: BACKGROUND: Community Health Workers (CHW) are a category of social workers described in many countries’ health systems as responsible for engaging people in their residences and communities, and other non-clinical spaces to enable access to health services, especially in low-income areas. These professionals have been exposed to numerous new risks during the COVID-19 pandemic. OBJECTIVE: This study describes how the COVID-19 pandemic is perceived by CHWs who work in poor communities or slums in Brazil. METHODS: We conducted an online survey with a random sample of 775 CHWs operating in 368 municipalities of the 26 Brazilian states. At a confidence level of 95%, results of the survey were subject to a maximum sampling error of 4%. RESULTS: Our data indicate that the negationist agenda increases the challenges to the performance of CHWs within low-income communities, preventing the consensus on the necessity of social distancing, business closures and other measures to face the COVID-19 pandemic. CONCLUSION: The pandemic imposes unexpected challenges on the usual modes of interaction of public health officers with poor communities. This study provides evidence that these challenges have been ignored or minimized in Brazilian policy prescriptions for primary care in the face of the COVID-19 pandemic.

Study of Renewable Silica Powder Influence in the Preparation of Bioplastics from Corn and Potato Starch

Abstract: In the present study, 0.5–1.5% silica powder, from sugarcane waste ash, was incorporated into corn and potato starch bioplastics doped with sodium silicate solution to improve the properties of elongation at break and increase the thermal resistance of the bioplastics. The starch-based bioplastics were produced by casting and characterized by color analyses, transparency, opacity apparent, humidity, thickness, tensile strength, elongation at break, FTIR, DSC, SEM, and biodegradation assay. The addition of 0.5% of silica powder improved the elongation at break of the corn starch-based bioplastics. The sample CS5-P0.5 presented the highest percentage of elongation at the break among the studied samples, increased from 59.2% (without silica powder) to 78.9% (with silica powder). For potato starch bioplastic the addition of 0.5% of silica powder did not improve elongation at break but increased the thermal resistance. Increased until 17 °C for PS5-P0.5 sample and until 11 °C for PS7.5-P0.5 sample. The bioplastics of potato starch were biodegraded in 5 days, and those of corn starch took almost 40 days. Silica powder inhibited the growth of fungi in starch bioplastics.

Enhancing NIR emission in ZnAl2O4:Nd,Ce nanofibers by co-doping with Ce and Nd

Abstract: Development of new near infrared luminescent (NIR) emitters improves our understanding of their fundamental structure–property relationships. The ability to use efficient energy transfer to convert ultraviolet or visible light photons to enhance the NIR emission has attracted a great deal of attention in down-conversion applications. Taking advantage of the sol–gel impregnation process and growth of materials along a support or template, core–shell structured nanofibers of ZnAl2O4 – based ceramic doped with cerium and neodymium were synthesized with the help of an elaborate facile and cost-efficient strategy. The color-tunable emissions make this material a suitable host for a wide range of applications, e.g., bio-imaging, security markers, imaging devices, optical coatings, and solar cells. This research correlates the defects and the remarkable optical properties of the developed structures. Specified conditions of sol–gel processing combined with the incorporation of rare-earth elements in various concentrations provide the possibility of tuning the ratio between Ce3+ and Ce4+ in the nanofibers with an average diameter of 50 nm and, therefore, their functional response. It is important to clarify the role of trivalent and tetravalent cerium cations in the modulation of NIR emission to establish the luminescence mechanism. The NIR emitter luminescent compound ZnAl2O4:Nd,Ce, which adopts a spinel-type structure, is studied using the X-ray absorption near-edge structure technique. For the first time, this study reveals the energy transfer from Ce3+ to Nd3+ and the enhancement of the NIR emission due to the presence of Ce4+ in the ZnAl2O4:Nd,Ce spinel compound. Cytotoxicity analyses suggest the viability of the synthesized nanofibers, which opens new avenues in bio-imaging applications.

Combination of Cu-Pt-Pd nanoparticles supported on graphene nanoribbons decorating the surface of TiO2 nanotube applied for CO2 photoelectrochemical reduction

Abstract: The photoelectrocatalysis (PEC) technique was applied in CO2 reduction using different proportions of Cu, Pd, and Pt supported on graphene nanoribbons (GNR) and deposited on the surfaces of TiO2 nanotubes. Altogether, nine combinations of TiO2-NT/GNR-metal were assembled, although only three of them efficiently promoted the generation of methanol and ethanol in high quantities. Comparison with the photocatalysis, photolysis, and electrocatalysis techniques showed the extremely high efficiency of PEC, which enabled production of methanol and ethanol at levels around 19.2-fold and 44.4-fold higher, respectively, than photocatalysis, the second most efficient technique. The presence of metallic nanoparticles in the system facilitated CO2 reduction due to the trapping of the photogenerated electrons, prolonging their lifetime, lowering the reaction energy barrier for CO2 reduction, and provided active intermediates. Therefore, the assembly of these materials containing low amounts of metals is highly promising, since it can assist in alleviating environmental problems caused by CO2 emissions, while at the same time enabling the energetically efficient generation of compounds of commercial value.