Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 337
Filtrar
1.
Heliyon ; 10(19): e37653, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-39381115

RESUMO

Abstract: The strong increase in global demand for lithium, driven by the ion battery market and the use of this non-metallic mineral in various economic sectors such as mining (as a non-metallic and non-renewable mineral), health, technology, and geopolitical issues, has fueled the development of disruptive innovation, with new products linked to knowledge creation. These developments have included, among other things, the use of new processing techniques, the creation of new high-capacity cathode materials, the investigation of new sources of lithium, and increased recycling of lithium-ion batteries. This article's primary goal is to assess how this knowledge gap is related with innovation issues using the analysis of the scholar as a case study. Additionally, the examination of public policy related to the lithium business will be continued and updated in this publication. This study uses computerized bibliometric analysis based on the R program and Biblioshiny, a web interface for Bibliometrix analysis. One of the earliest studies to examine the discrepancy between lithium production and consumption based on innovation is this one. The research's contribution is to highlight the disparities and gaps in knowledge generation between producer and consumer countries, which creates a great opportunity to develop better public policies that use existing knowledge and promote collaborations between mining and technology companies for the development of a more sustainable, efficient, effective and competitive industry with future societies.

2.
Molecules ; 29(19)2024 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-39407573

RESUMO

A zeolitic sample, named MT-ZLSH, was synthesized using mining tailings (MT) as the precursor material, resulting in a structure comprising: Linde type A (LTA) and sodalite-hydroxysodalite (ZLSH). This naming convention reflects the material's origin and its structural characteristics. The material was further modified by incorporating lithium, producing MT-ZLSH-Li+. Physicochemical characterizations were performed, and the material was evaluated for its potential to remove methylene blue (MB) from synthetic wastewater through adsorption and photocatalysis. Efficient adsorption was observed under typical wastewater pH conditions, with a maximum adsorption capacity of 23.4 mg·g-1, which fit well with the Langmuir isotherm model. The key mechanisms governing MB adsorption were identified as ion exchange, electrostatic attraction, and hydrogen bonding. The adsorption process was exothermic, with kinetic data fitting both the pseudo-second order and intraparticle diffusion models, achieving 82% removal and a maximum adsorption capacity of 40 mg·g-1 over 12 h. MB adsorption followed a two-step process, initially involving film diffusion, followed by intraparticle diffusion. Additionally, photocatalytic degradation of MB achieved 77% degradation within 180 min. However, a decrease in reusability was observed during a second cycle of MB adsorption and photodegradation, highlighting the need for further optimization to enhance the material's long-term performance.

3.
Microsc Res Tech ; 2024 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-39287992

RESUMO

The purpose of this study was to introduce a novel and simple method of evaluating the crystal length and crystalline content of lithium disilicate dental ceramics using images obtained from scanning electron microscopy (SEM) and analyzed with ImageJ (NIH) processing software. Three evaluators with varying experience levels assessed the average crystal length and percentage of crystalline content in four commercial lithium disilicate reinforced glass ceramic materials: IPS e.max (Ivoclar Vivadent), Rosetta SM (Hass), T-Lithium (Talmax), and IRIS CAD (Tianjin). The specimens, prepared from partially crystallized CAD/CAM blocks (3.0 mm3), were fully crystallized and treated with 5% hydrofluoric acid for 20 s prior to SEM analysis. After acquiring the SEM images, ImageJ software was used to evaluate the average crystal length and crystalline content on the surface of the different ceramics. An inter-operator agreement was observed (ICC/p = 0.724), indicating that assessments by the various operators were similar across all ceramic materials tested (p < 0.001). When crystal length and crystalline content were compared, IRIS CAD exhibited significant differences compared to the other materials (p < 0.001), showing a less dense crystalline matrix based on the average length of crystals and the percentage of crystals per unit area. The use of this software facilitated the evaluation of crystalline content and average crystal lengths in dental ceramics using SEM images, and demonstrated very low variability among different operators. RESEARCH HIGHLIGHTS: The described method, using ImageJ open-source software, provides precise and reliable measurements of crystal length and crystalline content in lithium disilicate ceramics, with high inter-operator agreement. The proposed method identified higher crystalline content in IPS e.max CAD compared to Rosetta SM CAD and T-lithium CAD ceramics, while IRIS CAD exhibited significantly lower crystalline content and larger average crystal length. The novel, simplified method for assessing crystal length and crystalline content presented in this study may also be useful for evaluating other dental ceramics.

4.
Molecules ; 29(18)2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-39339471

RESUMO

Lithium, a natural element, has been employed as a mental stabilizer in psychiatric treatments; however, some reports indicate it has an anticancer effect, prompting the consideration of repurposing lithium for cancer treatment. The potential anticancer use of lithium may depend on its form (salt type) and the type of cancer cells targeted. Little is known about the effects of Li2CO3 or LiCl on cancer cells, so we focused on exploring their effects on proliferation, apoptosis, migration, and cell cycle as part of the hallmarks of cancer. Firstly, we established the IC50 values on HeLa, SiHa, and HaCaT cells with LiCl and Li2CO3 and determined by crystal violet that cell proliferation was time-dependent in the three cell lines (IC50 values for LiCl were 23.43 mM for SiHa, 23.14 mM for HeLa, and 15.10 mM for HaCaT cells, while the IC50 values for Li2CO3 were 20.57 mM for SiHa, 11.52 mM for HeLa, and 10.52 mM for HaCaT cells.) Our findings indicate that Li2CO3 and LiCl induce DNA fragmentation and caspase-independent apoptosis, as shown by TUNEL, Western Blot, and Annexin V/IP assay by flow cytometry. Also, cell cycle analysis showed that LiCl and Li2CO3 arrested the cervical cancer cells at the G1 phase. Moreover, lithium salts displayed an anti-migratory effect on the three cell lines observed by the wound-healing assay. All these findings imply the viable anticancer effect of lithium salts by targeting several of the hallmarks of cancer.


Assuntos
Apoptose , Movimento Celular , Proliferação de Células , Cloreto de Lítio , Neoplasias do Colo do Útero , Humanos , Cloreto de Lítio/farmacologia , Proliferação de Células/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/metabolismo , Movimento Celular/efeitos dos fármacos , Feminino , Células HeLa , Linhagem Celular Tumoral , Antineoplásicos/farmacologia , Carbonato de Lítio/farmacologia , Ciclo Celular/efeitos dos fármacos , Reposicionamento de Medicamentos
5.
Crit Anthropol ; 44(3): 381-399, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39301416

RESUMO

This article uses the ethnography of the prelives of lithium industrialization in Bolivia to contribute to wider debates - in anthropology and beyond - about the essentially contested nature of the green energy transition. Based on research conducted between 2019 and 2023, the article examines the topographies of production and sociopolitical mobilization that are entangled with Bolivia's state-controlled lithium project but which resist the various pressures to reorient social and productive worlds around arguably the most important 'critical' mineral for climate policy-making. The article develops a theoretical framework for understanding these localized counter-futurities, one in which the image of scale-making takes on both vertical and horizontal dimensions. An anthropology of energy, climate justice, and resource imaginaries that is critically attuned to these inter-scalar frictions is one that must also be able to project itself through the kaleidoscope of competing energy narratives as a form of both demystification and ethnographic truth-telling.

6.
Dent Mater ; 2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39304479

RESUMO

OBJECTIVES: To evaluate the influence of microstructure and chemical composition on the optical properties of CAD-CAM lithium disilicate glass-ceramics. METHODS: Samples (n = 5; 1.0 mm thickness) of shades A1, A2, and A3 were fabricated from CAD-CAM ceramic blocks (Ivoclar Vivadent): IPS e.max® CAD LT (emLT) and HT (emHT). Samples were polished to 1.0 ± 0.01 mm in thickness. The optical properties (R- reflectance; T- transmittance; µs'- reduced scattering and µa- absorption coefficients) from the post-crystallized samples were determined using the inverse adding-doubling (IAD) method based on integrating-sphere measurements. Additionally, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used to evaluate the microstructural properties. Energy-dispersive X-ray (EDX) was employed to analyze the chemical composition. The chemical and structural characterization were performed before and after crystallization of the ceramic samples. RESULTS: emLT showed higher values of µs'and lower values of µa and T than emHT for each shade in all wavelengths (p < 0.003). Considering T for emHT, there were no statistical differences for shades A1 and A2 at 488 nm and 514.5 nm (p > 0.003) and shades A1 and A3 at 457.9 nm (p > 0.003). emLT showed particle length ranging from 0.74 to 2.78 µm (mean = 1.57 µm and RF-relative frequency = 28 %) and particle width ranging from 0.21 to 0.74 µm (mean = 0.30 µm and RF = 31 %). emHT showed particle length ranging from 0.83 to 3.08 µm (mean = 1.86 µm and RF = 21 %) and particle width ranging from 0.24 to 1.12 µm (mean = 0.56 µm and RF = 28 %). In comparison with emHT, emLT showed greater vol% for C, K, and Zr and lower vol% for O and Al. SIGNIFICANCE: The optical properties of CAD-CAM lithium disilicate glass-ceramics are influenced by the chemical composition and, consequently, by the material microstructure.

7.
Environ Sci Pollut Res Int ; 31(43): 55187-55203, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39223413

RESUMO

Lithium (Li) exploitation promotes socioeconomic advances but may result in harmful environmental impacts. Thus, species selection for recovering environments degraded by Li mining is essential. We investigated the tolerance and early growth of four tree species to Li ore tailings (LOT), Enterolobium contortisiliquum and Handroanthus impetiginosus with wide geographic distribution and Hymenaea courbaril and H. stigonocarpa with restricted geographic distribution. The plants grew in LOT and soil for 255 days to evaluate photosynthesis, growth, and mineral nutrition. LOT negatively affected species growth, reducing the length of stems, roots, and biomass through structural and nutritional impoverishment. LOT favored the accumulation of Mg and decreased the absorption of K. The species presented a reduction in potential quantum efficiency and the chlorophyll index (b and total). E. contortisiliquum was the least tolerant species to LOT, and H. courbaril and H. stigonocarpa maintained their mass production in LOT, indicating greater tolerance to tailings. Furthermore, H. courbaril presented a translocation factor > 1 for Li and Mn, indicating the potential for phytoextraction of these metals. Our results offer first-time insights into the impacts of LOT on the early development of tree species with different geographic distribution ranges. This study may help in the tree species selection with a phytoremediation role, aiming at the recovery of areas affected by Li's mining activity.


Assuntos
Lítio , Mineração , Fotossíntese , Árvores , Fotossíntese/efeitos dos fármacos , Poluentes do Solo
8.
Sci Rep ; 14(1): 20753, 2024 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-39237591

RESUMO

Currently, there are no national and international certified reference materials (CRM) in lithium clays that can make reliable and traceable lithium measurements for the International System of Units (SI). Hence, it is necessary to have references to meet the needs in terms of mining and activities that involve the use of lithium to favor the economy derived from its multiple uses and associated benefits in the exploration, exploitation, and handling of lithium ore. In this study, a candidate for reference material (RM) of Li in clays was developed and certified based on the provisions of ISO 17034:2016 and ISO Guide 35:2017. Different mass sizes of the RM (0.05, 0.1, and 0.25 g) were used to evaluate homogeneity. An isochronous study (short-term stability) was carried out in the assessment of stability, influenced by the effects of transport at different temperatures (20, 40, and 50 °C) for a determined time of 6 weeks, in addition to a classic (long-term) study for 19 weeks. The sample was treated using microwave-assisted acid digestion and Li measurements were performed using the analytical technique of Flame Atomic Absorption Spectrometry (FAAS). The CRM is homogeneous for the sample mass sizes of 0.05 and 0.1 g, and the mass fraction of w(Li) was stable in the RM for temperatures of 20, 40, and 50 °C. The determined period of validity was 3 years.

9.
Eur J Neurosci ; 60(6): 5141-5155, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39119736

RESUMO

This study aimed to investigate the behavioral responses and circadian rhythms of mice to both rapid and gradual increases in photoperiod, mimicking the transition from winter to summer, which is associated with a heightened prevalence of hospitalizations for mania and suicidal behavior. Behavioral tests were performed in C57BL/6 male mice exposed to a transitional photoperiod, from short to long durations. To determine if circadian rhythms are affected, we measured spontaneous locomotor activity and body temperature. Mice exhibited heightened exploratory and risk-taking behaviors compared with equatorial and static long (16:8 h of light-dark cycle for several days) groups. These behaviors were prevented by lithium. Spontaneous locomotor activity and body temperature rhythms persisted and were effectively synchronized; however, the relative amplitude of activity and interdaily stability were diminished. Additionally, the animals displayed increased activity during the light phase. Photoperiodic transition modulates behavior and circadian rhythms, mirroring certain features observed in bipolar disorder patients. This study introduces an animal model for investigating mania-like behavior induced by photoperiodic changes, offering potential insights for suicide prevention strategies and the management of mood disorders.


Assuntos
Ritmo Circadiano , Mania , Camundongos Endogâmicos C57BL , Fotoperíodo , Animais , Masculino , Ritmo Circadiano/fisiologia , Camundongos , Modelos Animais de Doenças , Temperatura Corporal/fisiologia , Locomoção/fisiologia , Comportamento Exploratório/fisiologia , Comportamento Animal/fisiologia , Assunção de Riscos , Transtorno Bipolar/fisiopatologia , Atividade Motora/fisiologia
10.
Int J Mol Sci ; 25(15)2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39126018

RESUMO

Cassava starch solid biopolymer electrolyte (SBPE) films were prepared by a thermochemical method with different concentrations of lithium triflate (LiTFT) as a dopant salt. The process began with dispersing cassava starch in water, followed by heating to facilitate gelatinization; subsequently, plasticizers and LiTFT were added at differing concentrations. The infrared spectroscopy analysis (FTIR-ATR) showed variations in the wavenumber of some characteristic bands of starch, thus evidencing the interaction between the LiTFT salt and biopolymeric matrix. The short-range crystallinity index, determined by the ratio of COH to COC bands, exhibited the highest crystallinity in the salt-free SBPEs and the lowest in the SBPEs with a concentration ratio (Xm) of 0.17. The thermogravimetric analysis demonstrated that the salt addition increased the dehydration process temperature by 5 °C. Additionally, the thermal decomposition processes were shown at lower temperatures after the addition of the LiTFT salt into the SBPEs. The differential scanning calorimetry showed that the addition of the salt affected the endothermic process related to the degradation of the packing of the starch molecules, which occurred at 70 °C in the salt-free SBPEs and at lower temperatures (2 or 3 °C less) in the films that contained the LiTFT salt at different concentrations. The cyclic voltammetry analysis of the SBPE films identified the redox processes of the glucose units in all the samples, with observed differences in peak potentials (Ep) and peak currents (Ip) across various salt concentrations. Electrochemical impedance spectroscopy was used to establish the equivalent circuit model Rf-(Cdl/(Rct-(CPE/Rre))) and determine the electrochemical parameters, revealing a higher conduction value of 2.72 × 10-3 S cm-1 for the SBPEs with Xm = 17 and a lower conduction of 5.80 × 10-4 S cm-1 in the salt-free SBPEs. It was concluded that the concentration of LiTFT salt in the cassava starch SBPE films influences their morphology and slightly reduces their thermal stability. Furthermore, the electrochemical behavior is affected in terms of variations in the redox potentials of the glucose units of the biopolymer and in their ionic conductivity.


Assuntos
Condutividade Elétrica , Eletrólitos , Manihot , Amido , Amido/química , Manihot/química , Eletrólitos/química , Termogravimetria , Biopolímeros/química , Mesilatos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Varredura Diferencial de Calorimetria
11.
Chempluschem ; : e202400486, 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39196606

RESUMO

Photo-switchable coatings for lithium ion batteries (LIB) can offer the possibility to control the diffusion processes from the electrode materials to the electrolyte and thus, for example, reducing the energy loss in the fully charged state. Fulgide derivatives, as known photo-switches, are investigated concerning their use as coating for vanadium pentoxide, a potential cathode material for LIB. With the help of Density Functional Theory calculations, two fulgide derivatives are characterized with respect to their photophysics, their aggregation behaviour on the cathode material and the ability to form self-assembled monolayers (SAM). Furthermore, the two states of the photo-switchable coating are tested with respect to lithium diffusion from the cathode material, passing the SAM and entering the electrolyte. We found a difference for the energy barriers depending on the state of the photo-switch, preferring its closed form. This behaviour can be used to prevent the loss of charge in batteries of portable devices.

12.
Rev Cient Odontol (Lima) ; 12(1): e182, 2024.
Artigo em Espanhol | MEDLINE | ID: mdl-39015314

RESUMO

Introduction: In oral rehabilitation, the use of ceramic restorations is widely accepted due to its aesthetic capacity to mimic the naturalness of the dental tissue, provide longevity of the material, and present a greater marginal fit compared to crowns with a metal structure. Termination lines are biological preparations whose function is to minimize the cervical opening of the marginal seal. Consequently, analyzing the behavior of restorative materials under compressive forces decreases the risk of fracture and increases the success of the treatment. Objective: To compare the compressive stresses of lithium disilicate crowns with three different finishing lines. Methodology: In silico study of the simulation of a dental preparation on a lower right first molar with chamfer (0.6 mm), shoulder (0.5 mm) and deep chamfer (0.5 mm) finish lines. Using the SolidWorks®ï¸ version 2017 software, the maximum stresses, minimum stresses, and location of the compressive force were collected on the Megapascal (Mpa) measurement scale. Results: The chamfer type termination line (0.6mm) obtained a lower compressive stress compared to the other two shoulder type termination lines (0.5mm) and deep chamfer (0.5mm). Conclusions: It was shown that the chamfer type finishing line (0.6mm) presented a better force distribution, determining greater reliability in the selection of this finishing line with the use of a lithium disilicate crown in a unitary manner.

13.
J Prosthodont Res ; 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38925985

RESUMO

PURPOSE: Fixed restorations and dental enamel have different structures that produce different wear on opposing teeth, resulting in clinical problems. Therefore, it is necessary to determine the type of restoration that causes less wear on naturally opposing teeth to make recommendations. The objective of this study was to systematically analyze the evidence from observational studies and clinical trials on enamel wear in different ceramic restorations. STUDY SELECTION: The designs of the included studies were randomized clinical trials (RTCs), non-randomized clinical trials (non-RTCs), and observational studies (OS). The studies must answer the research question, be available in full text, be written in English or Spanish, and have had at least six months of follow-up. Protocol number: CRD42023397759. RESULTS: After screening 499 records, 20 RTCs were subjected to data extraction, 10 were excluded, 10 were included in the systematic review, and only 5 were included in the network meta-analysis. The risk of bias assessment reported moderate to high risk of bias, quality, and certainty of evidence was evaluated and rated as moderate. Network meta-analysis showed higher enamel wear was observed in natural dental enamel against metal-ceramic antagonists. CONCLUSIONS: Enamel wear occurs in all teeth, even when the antagonist is a natural tooth. The wear is larger on surfaces with the ceramic crown antagonists studied (metal-ceramic, glazed zirconia, and polished zirconia). It is necessary to conduct additional clinical trials with larger follow-up periods and sample sizes.

14.
Acta Crystallogr E Crystallogr Commun ; 80(Pt 6): 620-624, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38845724

RESUMO

The reaction of lithium hexa-methyl-disilyl-amide, [Li{N(Si(CH3)3)2}] (LiHMDS), with 4,4-dimethyl-2-phenyl-2-oxazoline (Phox, C11H13NO) in hexane produced colourless crystals of bis-(4,4-dimethyl-2-phenyl-2-oxazoline-κN)(hexa-methyl-disilyl-amido-κN)lithium, [Li(C6H18NSi2)(C11H13NO)2] or [Li{N(Si(CH3)3)2}(Phox)2] in high yield (89%). Despite the 1:1 proportion of the starting materials in the reaction mixture, the product formed with a 1:2 amide:oxazoline ratio. In the unit cell of the C2/c space group, the neutral mol-ecules lie on twofold rotation axes coinciding with the Li-N(amide) bonds. The lithium(I) centre adopts a trigonal-planar coordination geometry with three nitro-gen donor atoms, one from the HMDS anion and two from the oxazolines. All ligands are monodentate. In the phenyl-oxazoline units, the dihedral angle defined by the five-membered heterocyclic rings is 35.81 (5)°, while the phenyl substituents are approximately face-to-face, separated by 3.908 (5) Å. In the amide, the methyl groups assume a nearly eclipsed arrangement to minimize steric repulsion with the analogous substituents on the oxazoline rings. The non-covalent inter-actions in the solid-state structure of [Li{N(Si(CH3)3)2}(Phox)2] were assessed by Hirshfeld surface analysis and fingerprint plots. This new compound is attractive for catalysis due to its unique structural features.

15.
Ageing Res Rev ; 99: 102396, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38942199

RESUMO

Lithium therapy received approval during the 1970s, and it has been used for its antidepressant, antimanic, and anti-suicidal effects for acute and long-term prophylaxis and treatment of bipolar disorder (BPD). These properties have been well established; however, the molecular and cellular mechanisms remain controversial. In the past few years, many studies demonstrated that at the cellular level, lithium acts as a regulator of neurogenesis, aging, and Ca2+ homeostasis. At the molecular level, lithium modulates aging by inhibiting glycogen synthase kinase-3ß (GSK-3ß), and the phosphatidylinositol (PI) cycle; latter, lithium specifically inhibits inositol production, acting as a non-competitive inhibitor of inositol monophosphatase (IMPase). Mitochondria and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) have been related to lithium activity, and its regulation is mediated by GSK-3ß degradation and inhibition. Lithium also impacts Ca2+ homeostasis in the mitochondria modulating the function of the lithium-permeable mitochondrial Na+-Ca2+exchanger (NCLX), affecting Ca2+ efflux from the mitochondrial matrix to the endoplasmic reticulum (ER). A close relationship between the protease Omi, GSK-3ß, and PGC-1α has also been established. The purpose of this review is to summarize some of the intracellular mechanisms related to lithium activity and how, through them, neuronal aging could be controlled.


Assuntos
Senescência Celular , Compostos de Lítio , Neurônios , Neurônios/efeitos dos fármacos , Compostos de Lítio/farmacologia , Fármacos Neuroprotetores/farmacologia , Enzimas/metabolismo , Inositol/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Cálcio/metabolismo , Humanos , Animais , Senescência Celular/efeitos dos fármacos
16.
Small ; 20(31): e2306895, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38607269

RESUMO

Lithium-oxygen batteries show promising energy storage potential with high theoretical energy density; however, further investigation of chemical reactions is required. In this study, experimental Raman and theoretical analyzes are performed for a Li-O2 battery with LiClO4/dimethyl sulfoxide (DMSO) electrolyte and carbon cathode to understand the role of intermediate species in the reactional mechanism of the cell using a high donor number solvent. Operando Raman results reveal reversible changes in the DMSO bands, in addition to the formation and decomposition of Li2O2. On discharge, a decrease in DMSO polarizability is observed and bands of DMSO-Li+-anion interactions are evidenced and supported by ab initio density functional theory (DFT) calculations. Molecular dynamics (MD) force field simulations and operando Raman show that DMSO interacts with LiO2(sol), highlighting the stability of the electrolyte compared to the interaction with reactive O 2 - ${\rm O}_2^{-}$ . On charging, the presence of Li+ indicates the formation of a lithium-deficient phase, followed by the release of Li+ and oxygen. Therefore, this study contributes to understanding the discharge/charge chemistry of a Li-O2 cell, employing a common carbon cathode and DMSO electrolyte. The combination of a simple characterization technique in operando mode and theoretical studies provides essential information on the mechanism of Li-O2 system.

17.
Luminescence ; 39(4): e4732, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38556715

RESUMO

In the present work, glass samples in the (100 - x)B2O3-xLi2O binary system, with x varying from 30 to 50 mol%, were prepared using the conventional melting and moulding method, with the main objective of evaluating the thermoluminescence response when exposing these materials to ultraviolet (UV) radiation. Complementary analysis based on density, optical absorption on the UV-visible region (UV-vis absorbance), Fourier transform infrared spectroscopy on the medium region, X-ray diffraction, and differential thermal analysis measurements were performed. Thermoluminescence measurements of vitreous samples showed glow curves with at least one peak with a maximum temperature of ~170°C after exposure to UV radiation in the temperature range 50-250°C. Samples were also exposed to beta radiation in the temperature range 25-275°C, also showing single peaks with a maximum temperature of ~150°C.


Assuntos
Partículas beta , Boratos , Boratos/química , Compostos de Lítio , Temperatura
18.
Int J Mol Sci ; 25(6)2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38542200

RESUMO

Spodumene flotation stands as the most commonly used method to concentrate lithium minerals. However, it faces significant challenges related to low collector recoveries and similarity in the surface characteristics of the minerals, which make the effective separation of this valuable mineral difficult. For this reason, numerous researchers have conducted studies to address and confront this problem. In this work, an exhaustive bibliographic search was carried out using keywords and search queries, and the results were structured in three sections according to temporal, methodological, and thematic criteria. The first section covers the period from 1950 to 2004, focusing on experimental tests. The second section covers from 2004 to the present and focuses on flotation tests and measurement analysis. Simultaneously, the third section spans from 2011 to the present and is based on molecular dynamics simulations. Topics covered include spodumene surface properties, the influence of metal ions, pre-treatment techniques, and the use of collectors. Ultimately, molecular dynamics simulations are positioned as a tool that accurately represents experimental phenomena. In this context, specialized software such as Materials Studio or Gromacs prove to be reliable instruments that allow a detailed study of mineral surfaces and other elements to be carried out, which justifies their consideration for future research in this scientific field.


Assuntos
Metais , Minerais , Lítio , Íons
19.
Rev. méd. Urug ; 40(1): e204, mar. 2024.
Artigo em Espanhol | LILACS, BNUY | ID: biblio-1560246

RESUMO

El suicidio es un fenómeno que además de las pérdidas humanas que involucra, repercute negativamente en familiares y allegados, produciendo a su vez enormes gastos en el sistema sanitario. En Uruguay, la tasa de suicidio no solo ha experimentado un aumento sostenido, representando una preocupación constante para las autoridades, sino que suele ser una de la más altas de Latinoamérica, en 2022 fue de 23,08 cada 100.000 habitantes. Reconociendo que el suicidio es un fenómeno multifactorial grave, diversos estudios han indagado sobre la posible correlación entre la presencia de litio en agua corriente y tasas de suicidio, habiéndose observado una relación inversa, lo que permitiría considerar el litio como eventualmente protector de la conducta suicida. El presente estudio pretende abordar dicha correlación en los departamentos de Rocha y Montevideo, de Uruguay. Los resultados obtenidos no son concluyentes. En cuanto a las concentraciones de litio presentes en agua corriente, en general son menores a las señaladas en otros estudios como protectoras (30 µ/L). Es necesario profundizar en este eje de discusión, como en otros, para obtener un diagnóstico más detallado de este complejo y sentido fenómeno.


Suicide is a phenomenon that, in addition to the human losses it involves, has a negative impact on family members and acquaintances, leading to enormous costs in the healthcare system. In Uruguay, the suicide rate has not only experienced a sustained increase, representing a constant concern for authorities, but it also tends to be one of the highest in Latin America, reaching 23.08 per 100,000 inhabitants in 2022. Recognizing that suicide is a serious multifactorial phenomenon, several studies have investigated the possible correlation between the presence of lithium in tap water and suicide rates, noting an inverse relationship. This suggests that lithium could potentially be considered protective against suicidal behavior. This study aims to address this correlation in the departments of Rocha and Montevideo, Uruguay. The results obtained are inconclusive. Regarding the concentrations of lithium present in tap water, they are generally lower than those indicated in other studies as protective (30 µg/L). It is necessary to delve deeper into this axis of discussion, as in others, to obtain a more detailed diagnosis of this complex and profound phenomenon.


O suicídio é um fenómeno que, além das perdas humanas que envolve, tem um impacto negativo nos familiares e amigos, produzindo enormes gastos no sistema de saúde. No Uruguai, a taxa de suicídio não só tem registado um aumento sustentado, representando uma preocupação constante para as autoridades, mas geralmente é uma das mais altas da América Latina, sendo de 23,08 por 100.000 habitantes em 2022. Reconhecendo que o suicídio é um fenómeno multifatorial grave, vários estudos têm investigado a possível correlação entre a presença de lítio na água encanada e as taxas de suicídio; observa-se uma relação inversa, o que permitiria considerá-lo como um possível protetor do comportamento suicida. O presente estudo visa abordar esta correlação nos departamentos de Rocha e Montevidéu no Uruguai. Os resultados obtidos não são conclusivos. Quanto às concentrações de litio presentes na água corrente, são geralmente inferiores às indicadas em outros estudos como protetoras (30 µ/L). É necessário aprofundar esta área de discussão como em outras linhas de pesquisa, e obter um diagnóstico mais detalhado deste fenômeno complexo e significativo.


Assuntos
Suicídio , Água Potável , Lítio/uso terapêutico , Uruguai/epidemiologia
20.
Environ Mol Mutagen ; 65(3-4): 121-128, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38385761

RESUMO

Elevated concentrations of arsenic, lithium and boron in drinking water have already been reported in Bolivia. Arsenic is known to cause genotoxicity but that caused by lithium and boron is less well known. The aim of the present cross-sectional study was to evaluate potential genotoxic effects of exposure to arsenic, while considering exposure to lithium and boron and genetic susceptibility. Women (n = 230) were recruited in villages located around Lake Poopó. Exposure to arsenic was determined as the sum of concentrations of arsenic metabolites inorganic arsenic, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in urine. Exposure to lithium and boron was determined based on their concentrations in urine. Genetic susceptibility was determined by GSTM1 (glutathione S-transferase-mu-1) and GSTT1 (glutathione S-transferase-theta-1) null genotypes and AS3MT (Arsenite Methyltransferase) rs3740393. Genotoxicity was measured in peripheral blood leukocytes using the comet assay. The geometric means of arsenic, lithium, and boron concentrations were 68, 897, and 3972 µg/L, respectively. GSTM1 and GSTT1 null carriers had more DNA strand breaks than gene carriers (p = .008, p = .005). We found no correlation between urinary arsenic and DNA strand breaks (rS = .03, p = .64), and only a weak non-significant positive association in the adjusted multivariate analysis (ß = .09 [-.03; .22], p = .14). Surprisingly, increasing concentrations of lithium in urine were negatively correlated with DNA strand breaks (rS = -.24, p = .0006), and the association persisted in multivariate analysis after adjusting for arsenic (ß = -.22 [-.36; -.08], p = .003). We found no association between boron and DNA strand breaks. The apparent protective effect of lithium merits further investigation.


Assuntos
Arsênio , Boro , Água Potável , Glutationa Transferase , Lítio , Poluentes Químicos da Água , Humanos , Estudos Transversais , Feminino , Arsênio/urina , Arsênio/toxicidade , Bolívia , Glutationa Transferase/genética , Adulto , Lítio/urina , Boro/urina , Poluentes Químicos da Água/toxicidade , Pessoa de Meia-Idade , Exposição Ambiental , Dano ao DNA/efeitos dos fármacos , Ensaio Cometa , Metiltransferases/genética , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA