Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 9.033
Filtrar
1.
Water Sci Technol ; 89(9): 2429-2439, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38747958

RESUMO

Sediment microbial fuel cells (SMFCs) represent a technology that can enhance sediment quality through processes such as nutrient suppression while simultaneously generating electricity from microorganisms. Despite its importance in elucidating the principles of nutrient suppression, the complex behavior of various ions within this context has been rarely explored. Herein, we applied an SMFC and systematically evaluated alterations in ion concentrations in interstitial and overlying waters. The SMFC deployment substantially decreased Na+ concentrations and increased Cl- levels in the interstitial water. This intriguing phenomenon was attributed to reactions driven by the electrodes. These reactions induced remarkable shifts in pH. Consequently, this pH shift triggered the leaching of heavy metals, particularly Fe, and decreased HCO3- concentrations within the interstitial water, thereby inducing the migration of other ions, including Na+ and Cl-, as compensation. Moreover, the PO43- concentration in interstitial water showed an increasing trend upon SMFC application, which contradicts the results of several previous reports. This increase was primarily attributed to the release of PO43-caused by the leaching of Fe salts, which was triggered by the pH shift. These findings provide new insights into sediment improvement research through SMFCs, enhancing our understanding of the fundamental principles and broadening the potential applications of this technology.


Assuntos
Fontes de Energia Bioelétrica , Sedimentos Geológicos , Concentração de Íons de Hidrogênio , Sedimentos Geológicos/química , Íons/química
2.
Anal Chim Acta ; 1308: 342661, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38740461

RESUMO

BACKGROUND: Timely diagnosis and prevention of diseases require rapid and sensitive detection of biomarkers from blood samples without external interference. Abnormal electrolyte ion levels in the blood are closely linked to various physiological disorders, including hypertension. Therefore, accurate, interference-free, and precise measurement of electrolyte ion concentrations in the blood is particularly important. RESULTS: In this work, a colorimetric sensor based on a biphasic microdroplet extraction is proposed for the detection of electrolyte ions in the blood. This sensor employs mini-pillar arrays to facilitate contact between adjacent blood microdroplets and organic microdroplets serving as sensing phases, with any color changes being monitored through a smartphone's colorimetric software. The sensor is highly resistant to interference and does not require pre-treatment of the blood samples. Remarkably, the sensor exhibits exceptional reliability and stability, allowing for rapid enrichment and detection of K+, Na+, and Cl- in the blood within 10 s (Cl-), 15 s (K+) and 40 s (Na+) respectively. SIGNIFICANCE: The colorimetric sensor based on biphasic microdroplet extraction offers portability due to its compact size and ease of operation without the need for large instruments. Additionally, it is location-independent, making it a promising tool for real-time biomarker detection in body fluids such as blood.


Assuntos
Colorimetria , Eletrólitos , Potássio , Colorimetria/métodos , Eletrólitos/química , Humanos , Potássio/sangue , Sódio/sangue , Cloretos/sangue , Íons/química
3.
Int J Mol Sci ; 25(9)2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38732218

RESUMO

Boronate esters are a class of compounds containing a boron atom bonded to two oxygen atoms in an ester group, often being used as precursors in the synthesis of other materials. The characterization of the structure and properties of esters is usually carried out by UV-visible, infrared, and nuclear magnetic resonance (NMR) spectroscopic techniques. With the aim to better understand our experimental data, in this article, the density functional theory (DFT) is used to analyze the UV-visible and infrared spectra, as well as the isotropic shielding and chemical shifts of the hydrogen atoms 1H, carbon 13C and boron 11B in the compound 4-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)benzaldehyde. Furthermore, this study considers the change in its electronic and spectroscopic properties of this particular ester, when its boron atom is coordinated with a fluoride anion. The calculations were carried out using the LSDA and B3LYP functionals in Gaussian-16, and PBE in CASTEP. The results show that the B3LYP functional gives the best approximation to the experimental data. The formation of a coordinated covalent B-F bond highlights the remarkable sensitivity of the NMR chemical shifts of carbon, oxygen, and boron atoms and their surroundings. Furthermore, this bond also highlights the changes in the electron transitions bands n → π* and π → π* during the absorption and emission of a photon in the UV-vis, and in the stretching bands of the C=C bonds, and bending of BO2 in the infrared spectrum. This study not only contributes to the understanding of the properties of boronate esters but also provides important information on the interactions and responses optoelectronic of the compound when is bonded to a fluorine atom.


Assuntos
Benzaldeídos , Benzaldeídos/química , Espectroscopia de Ressonância Magnética , Teoria da Densidade Funcional , Flúor/química , Boro/química , Modelos Moleculares , Ésteres/química , Espectrofotometria Infravermelho , Estrutura Molecular , Íons/química
4.
Colloids Surf B Biointerfaces ; 238: 113891, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38615392

RESUMO

The three-dimensional-printed Ti6Al4V implant (3DTi) has been widely accepted for the reconstruction of massive bone defects in orthopedics owing to several advantages, such as its tailored shape design, avoiding bone graft and superior bone-implant interlock. However, the osteoinduction activity of 3DTi is inadequate when applied clinically even though it exhibits osteoconduction. This study developes a comprehensive coatless strategy for the surface improvement of 3DTi through copper (Cu) ion implantation and ultraviolet (UV) photofunctionalization to enhance osteoinductivity. The newly constructed functional 3DTi (UV/Ti-Cu) achieved stable and controllable Cu doping, sustained Cu2+ releasing, and increased surface hydrophilicity. By performing cellular experiments, we determined that the safe dose range of Cu ion implantation was less than 5×1016 ions/cm2. The implanted Cu2+ enhanced the ALP activity and the apatite formation ability of bone marrow stromal cells (BMSCs) while slightly decreasing proliferation ability. When combined with UV photofunctionalization, cell adhesion and proliferation were significantly promoted and bone mineralization was further increased. Meanwhile, UV/Ti-Cu was conducive to the migration and angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro, theoretically facilitating vascular coupling osteogenesis. In conclusion, UV/Ti-Cu is a novel attempt to apply two coatless techniques for the surface modification of 3DTi. In addition, it is considered a potential bone substrate for repairing bone defects.


Assuntos
Ligas , Adesão Celular , Cobre , Células Endoteliais da Veia Umbilical Humana , Neovascularização Fisiológica , Osteogênese , Impressão Tridimensional , Titânio , Raios Ultravioleta , Titânio/química , Titânio/farmacologia , Ligas/química , Ligas/farmacologia , Osteogênese/efeitos dos fármacos , Cobre/química , Cobre/farmacologia , Adesão Celular/efeitos dos fármacos , Humanos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos , Animais , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Propriedades de Superfície , Íons/química , Proliferação de Células/efeitos dos fármacos , Próteses e Implantes , Células Cultivadas , Angiogênese
5.
J Phys Chem Lett ; 15(16): 4468-4476, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38631022

RESUMO

The underlying mechanism and intermediate formation in the self-assembly of aromatic amino acids, peptides, and proteins remain elusive despite numerous reports. We, for the first time, report that one can stabilize the intermediates by tuning the metal ion-amino acid interaction. Microscopic and spectroscopic investigations of the self-assembly of carboxybenzyl (Z)-protected phenylalanine (ZF) reveal that the bivalent metal ions eventually lead to the formation of fibrillar networks similar to blank ZF whereas the trivalent ions develop vesicle-like intermediates that do not undergo fibrillation for a prolonged time. The time-lapse measurement of surface charge reveals that the surface charge of blank ZF and in the presence of bivalent metal ions changes from a negative value to zero, implying unstable intermediates leading to the fibril network. Strikingly, a prominent charge inversion from an initial negative value to a positive value in the presence of trivalent metal ions imparts unusual stability to the metastable intermediates.


Assuntos
Fenilalanina , Fenilalanina/química , Propriedades de Superfície , Íons/química , Metais/química
6.
Int J Mol Sci ; 25(8)2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38674002

RESUMO

2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO•), a persistent nitronyl nitroxide radical, has been used for the detection and trapping of nitric oxide, as a redox mediator for batteries, for the activity estimation of antioxidants, and so on. However, there is no report on the reactivity of PTIO• in the presence of redox-inactive metal ions. In this study, it is demonstrated that the addition of scandium triflate, Sc(OTf)3 (OTf = OSO2CF3), to an acetonitrile (MeCN) solution of PTIO• resulted in an electron-transfer disproportionation to generate the corresponding cation (PTIO+) and anion (PTIO-), the latter of which is suggested to be stabilized by Sc3+ to form [(PTIO)Sc]2+. The decay of the absorption band at 361 nm due to PTIO•, monitored using a stopped-flow technique, obeyed second-order kinetics. The second-order rate constant for the disproportionation, thus determined, increased with increasing the Sc(OTf)3 concentration to reach a constant value. A drastic change in the cyclic voltammogram recorded for PTIO• in deaerated MeCN containing 0.10 M Bu4NClO4 was also observed upon addition of Sc(OTf)3, suggesting that the large positive shift of the one-electron reduction potential of PTIO• (equivalent to the one-electron oxidation potential of PTIO-) in the presence of Sc(OTf)3 may result in the disproportionation. When H2O was added to the PTIO•-Sc(OTf)3 system in deaerated MeCN, PTIO• was completely regenerated. It is suggested that the complex formation of Sc3+ with H2O may weaken the interaction between PTIO- and Sc3+, leading to electron-transfer comproportionation to regenerate PTIO•. The reversible disproportionation of PTIO• was also confirmed by electron paramagnetic resonance (EPR) spectroscopy.


Assuntos
Acetonitrilas , Óxidos N-Cíclicos , Escândio , Água , Acetonitrilas/química , Água/química , Óxidos N-Cíclicos/química , Escândio/química , Transporte de Elétrons , Oxirredução , Cinética , Íons/química , Imidazóis/química
7.
Int J Biol Macromol ; 267(Pt 1): 131273, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38569994

RESUMO

The nanopore-based translocation of a single-stranded RNA (ssRNA) in mixed salt solution has garnered increasing interest for its biological and technological significance. However, it is challenging to comprehensively understand the effects of the mixed ion species on the translocation dynamics due to their cooperation and competition, which can be directly reflected by the ion screening and neutralizing effects, respectively. In this study, Langevin dynamics simulation is employed to investigate the properties of ssRNA conformation and translocation in mixed Na+-Mg2+ ion environments. Simulation results reveal that the ion screening effect dominates the change in the ssRNA conformational size, the ion neutralizing effect controls the capture rate of the ssRNA by the nanopore, and both of them take charge of the different changes in translocation time of the ssRNA under various mixed ion environments. Under high Na+ ion concentration, as Mg2+ concentration increases, the ion neutralizing effect strengthens, weakening the driving force inside the nanopore, leading to longer translocation time. Conversely, at low Na+ concentration, an increase in Mg2+ concentration enhances the ion screening effect, aiding in faster translocation. Furthermore, these simulation results will be explained by quantitative analysis, advancing a deeper understanding of the complicated effects of the mixed Na+-Mg2+ ions.


Assuntos
Magnésio , Conformação de Ácido Nucleico , Sódio , Sódio/química , Sódio/metabolismo , Magnésio/química , Nanoporos , Simulação de Dinâmica Molecular , Íons/química , RNA/química
8.
Int J Biol Macromol ; 267(Pt 2): 131484, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38599421

RESUMO

Adopting effective and efficient techniques for the treatment of heavy metal pollution in water bodies plays an important role in guaranteeing the quality of water and the sustainable development of water resources. In this study, GO, MMT and SA were used as raw materials to compare the adsorption behaviors of three alginate-based adsorbents crosslinked with different valence metal ions (Ca2+, Fe3+ and Zr4+) on Cu(II). The aerogels were based on sodium alginate as the matrix material with unique slit-shaped pore structures formed by stacking effect of sheets and chemical bonding. It was found that the pore structures of the aerogels were denser and more orderly with the increase of the valence states of the crosslinked ions, and the affinity for Cu(II) in planar configuration was stronger. The Zr4+-GMSA aerogel had the maximum adsorption capacity of 126.68 mg/g and the Kd of Cu(II) was up to 50.80 L/g, which exhibited good preferential adsorption performance. The adsorption mechanism of Mn+-GMSA aerogels on Cu(II) was mainly ionic exchange, surface complexation and physical adsorption, which was explored by combining XPS and EDS characterizations of Mn+-GMSA before and after adsorption. This scheme can provide valuable and meaningful contribution to realize the selective recovery of Cu(II).


Assuntos
Alginatos , Cobre , Poluentes Químicos da Água , Purificação da Água , Cobre/química , Adsorção , Alginatos/química , Porosidade , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Íons/química , Cinética , Géis/química , Concentração de Íons de Hidrogênio
9.
Int J Biol Macromol ; 267(Pt 2): 131536, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38608993

RESUMO

Cellulosic hydrogels are widely used in various applications, as they are natural raw materials and have excellent degradability. However, their poor mechanical properties restrict their practical application. This study presents a facile approach for fabricating cellulosic hydrogels with high strength by synergistically utilizing salting-out and ionic coordination, thereby inducing the collapse and aggregation of cellulose chains to form a cross-linked network structure. Cellulosic hydrogels are prepared by soaking cellulose in an Al2(SO4)3 solution, which is both strong (compressive strength of up to 16.99 MPa) and tough (compressive toughness of up to 2.86 MJ/m3). The prepared cellulosic hydrogels exhibit resistance to swelling in different solutions and good biodegradability in soil. The cellulosic hydrogels are incorporated into strain sensors for human-motion monitoring by introducing AgNWs. Thus, the study offers a promising, simple, and scalable approach for preparing strong, degradable, and anti-swelling hydrogels using common biomass resources with considerable potential for various applications.


Assuntos
Celulose , Hidrogéis , Hidrogéis/química , Celulose/química , Força Compressiva , Humanos , Íons/química
10.
ACS Nano ; 18(19): 12096-12104, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38687972

RESUMO

Direct harvesting of energy from moist air will be a promising route to supply electricity for booming wearable and distributed electronics, with the recent rapid development of the moisture-enabled electricity generator (MEG). However, the easy spatial distortion of rigid MEG materials under severe deformation extremely inconveniences the human body with intense physical activity, seriously hindering the desirable applications. Here, an intrinsically stretchable moisture-enabled electricity generator (s-MEG) is developed based on a well-fabricated stretchable functional ionic gel (SIG) with a flexible double-network structure and reversible cross-linking interactions, demonstrating stable electricity output performance even when stretched up to 150% strain and high human body conformality. This SIG exhibits ultrahigh tensile strain (∼600%), and a 1 cm × 1 cm SIG film-based s-MEG can generate a voltage of ∼0.4 V and a current of ∼5.7 µA when absorbing water from humidity air. Based on the strong adhesion and the excellent interface combination of SIG and rough fabric electrodes induced by the fabrication process, s-MEG is able to realize bending or twisting deformation and shows outstanding electricity output stability with ∼90% performance retention after 5000 cycles of bending tests. By connecting s-MEG units in series or parallel, an integrated device of "moisture-powered wristband" is developed to wear on the wrist of humans and drive a flexible sensor for tracking finger motions. Additionally, a comfortable "moisture-powered sheath" based on s-MEGs is created, which can be worn like clothing on human arms to generate energy while walking and flexing the elbow, which is promising in the field of wearable electronics.


Assuntos
Fontes de Energia Elétrica , Géis , Dispositivos Eletrônicos Vestíveis , Humanos , Géis/química , Íons/química , Água/química , Eletrodos , Corpo Humano
11.
J Chromatogr A ; 1722: 464903, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38615559

RESUMO

High-Field Asymmetric Ion Mobility Spectrometry (FAIMS) is a technique for ion separation and detection based on ion mobility variation under high electronic field. While compensation voltage scanning speed is a fundamental parameter in FAIMS, its impact on spectra remains unclear. In this work, a function referred to as F-EMG is introduced to describe the impact of compensation voltage scanning speed on FAIMS spectra, and the properties of the function are studied. Theoretical analysis emphasizes the impact of the scanning speed on peak height, position, and symmetry, as well as the capability of the F-EMG function to progressively approach Gaussian function at lower scanning speeds. Furthermore, the function indicates that spectra obtained in positive and negative scanning modes exhibits symmetry. An experimental validation, conducted with a custom FAIMS setup and analyzing hydrogen sulfide, ethylbenzene, toluene, styrene, benzene and ammonia, confirms the model's influence on peak features, fitting accuracy, and exhibits a closer alignment with the Gaussian function at lower scanning speeds. Additionally, the experimental data indicate that the spectra show symmetry in positive and negative scanning models. This work not only improves understanding of FAIMS spectral analysis but also introduces a robust method for enhancing data accuracy across varying scanning speeds.


Assuntos
Espectrometria de Mobilidade Iônica , Espectrometria de Mobilidade Iônica/métodos , Modelos Teóricos , Íons/química , Íons/análise
12.
Int J Mol Sci ; 25(8)2024 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-38673912

RESUMO

In this work, we propose a comprehensive experimental study of the diffusion of nickel ions in combination with different cyclodextrins as carrier molecules for enhanced solubility and facilitated transport. For this, ternary mutual diffusion coefficients measured by Taylor dispersion method are reported for aqueous solutions containing nickel salts and different cyclodextrins (that is, α-CD, ß-CD, and γ-CD) at 298.15 K. A combination of Taylor dispersion and other methods, such as UV-vis spectroscopy, will be used to obtain complementary information on these systems. The determination of the physicochemical properties of these salts with CDs in aqueous solution provides information that allows us to understand solute-solvent interactions, and gives a significant contribution to understanding the mechanisms underlying diffusional transport in aqueous solutions, and, consequently, to mitigating the potential toxicity associated with these metal ions. For example, using mutual diffusion data, it is possible to estimate the number of moles of each ion transported per mole of the cyclodextrin driven by its own concentration gradient.


Assuntos
Ciclodextrinas , Níquel , Níquel/química , Ciclodextrinas/química , Difusão , Solubilidade , Íons/química
13.
Chemosphere ; 357: 142071, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38641290

RESUMO

To overcome the global water shortage, the treated wastewater is increasingly utilized in agricultural irrigation, and thus reducing freshwater consumption and increasing the water sustainability. Drip irrigation technology is the most appropriate irrigation method to utilize these water sources. However, its operating performance is negatively affected by calcium carbonate (CaCO3) scaling, which is one of the most dominant precipitations and also closely related to dissolved ions and the hydraulic characteristics inside irrigation systems. Thus, the effects of eight common dissolved ions (K+, Mg2+, Mn2+, Zn2+, Fe3+, NO3-, SO42-, and PO43-) in these water sources and four hydraulic shear stresses (0, 0.2, 0.4, and 0.6 Pa) on CaCO3 scaling formation were assessed in this study. Results showed that CaCO3 scaling was primarily formed of calcite and aragonite. Fe3+ would significantly accelerate the CaCO3 scaling accumulation, as it reduced the unit cell volume and chemical bonds of calcite, enhancing calcite adhesion and stability. On the other hand, Mg2+, Mn2+, NO3-, SO42-, and PO43- significantly inhibited CaCO3 scaling. Among them, Mg2+, Mn2+, and PO43- followed the typical water chemical precipitation rule, while NO3- increased water molecule diffusion rate and thus decreased the possibility that Ca2+ and CO32- to precipitate. SO42- grabbed the binding point belonging to CO32- and was adsorbed on the calcite crystal, which inhibited crystal growth. However, those treatments under K+ and Zn2+ did not reach a significant level due to their solubleness. During the precipitation of CaCO3, there were significant (p < 0.01) interactions between dissolved ions and hydraulic shear stresses. When hydraulic shear stresses varied, the effects of Fe3+ and SO42- on the CaCO3 scaling were relatively weakened, while that of Mg2+ was relatively strengthened. In return, dissolved ions affected the effect of hydraulic shear stresses on CaCO3 scaling. Overall, the results obtained could provide theoretical reference for high-efficiency utilization of treated wastewater for agricultural irrigation through the management of CaCO3 scaling.


Assuntos
Carbonato de Cálcio , Águas Residuárias , Carbonato de Cálcio/química , Águas Residuárias/química , Eliminação de Resíduos Líquidos/métodos , Íons/química , Irrigação Agrícola/métodos , Precipitação Química
14.
Chemosphere ; 357: 142051, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38648988

RESUMO

Water purification using adsorption is a crucial process for maintaining human life and preserving the environment. Batch and dynamic adsorption modes are two types of water purification processes that are commonly used in various countries due to their simplicity and feasibility on an industrial scale. However, it is important to understand the advantages and limitations of these two adsorption modes in industrial applications. Also, the possibility of using batch mode in industrial scale was scrutinized, along with the necessity of using dynamic mode in such applications. In addition, the reasons for the necessity of performing batch adsorption studies before starting the treatment on an industrial scale were mentioned and discussed. In fact, this review article attempts to throw light on these subjects by comparing the biosorption efficiency of some metals on utilized biosorbents, using both batch and fixed-bed (column) adsorption modes. The comparison is based on the effectiveness of the two processes and the mechanisms involved in the treatment. Parameters such as biosorption capacity, percentage removal, and isotherm models for both batch and column (fixed bed) studies are compared. The article also explains thermodynamic and kinetic models for batch adsorption and discusses breakthrough evaluations in adsorptive column systems. The review highlights the benefits of using convenient batch-wise biosorption in lab-scale studies and the key advantages of column biosorption in industrial applications.


Assuntos
Metais , Poluentes Químicos da Água , Purificação da Água , Adsorção , Purificação da Água/métodos , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo , Metais/química , Cinética , Termodinâmica , Íons/química
15.
J Phys Chem B ; 128(18): 4377-4384, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38657136

RESUMO

We have studied the excited states and structural properties for the complexes of cytosine (dC)10 chains with silver ions (Ag+) in a wide range of the Ag+ to DNA ratio (r) and pH conditions using circular dichroism, steady-state absorption, and fluorescence spectroscopy along with the ultrafast fluorescence upconversion technique. We also calculated vertical electronic transition energies and determined the nature of the corresponding excited states in some models of the cytosine-Ag+ complexes. We show that (dC)10 chains in the presence of silver ions form a duplex stabilized by C-Ag+-C bonds. It is also shown that the i-motif structure formed by (dC)10 chains is destabilized in the presence of Ag+ ions. The excited-state properties in the studied complexes depend on the amount of binding ions and the binding sites, which is supported by the calculations. In particular, new low-lying excited states appear when the second Ag+ ion interacts with the O atom of cytosine in the C-Ag+-C pairs. A similar picture is observed in the case when one Ag+ ion interacts with one cytosine via the N7 atom.


Assuntos
Citosina , Prata , Prata/química , Citosina/química , DNA/química , DNA de Cadeia Simples/química , Íons/química , Dicroísmo Circular , Espectrometria de Fluorescência , Concentração de Íons de Hidrogênio , Conformação de Ácido Nucleico
17.
J Am Soc Mass Spectrom ; 35(5): 902-911, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38609335

RESUMO

Traditionally, mass spectrometry (MS) output is the ion abundance plotted versus the ionic mass-to-charge ratio m/z. While employing only commercially available equipment, Charge Determination Analysis (CHARDA) adds a third dimension to MS, estimating for individual peaks their charge states z starting from z = 1 and color coding z in m/z spectra. CHARDA combines the analysis of ion signal decay rates in the time-domain data (transients) in Fourier transform (FT) MS with the interrogation of mass defects (fractional mass) of biopolymers. Being applied to individual isotopic peaks in a complex protein tandem (MS/MS) data set, CHARDA aids peptide mass spectra interpretation by facilitating charge-state deconvolution of large ionic species in crowded regions, estimating z even in the absence of an isotopic distribution (e.g., for monoisotopic mass spectra). CHARDA is fast, robust, and consistent with conventional FTMS and FTMS/MS data acquisition procedures. An effective charge-state resolution Rz ≥ 6 is obtained with the potential for further improvements.


Assuntos
Análise de Fourier , Espectrometria de Massas em Tandem , Espectrometria de Massas em Tandem/métodos , Biopolímeros/química , Biopolímeros/análise , Íons/química , Cor
18.
ACS Sens ; 9(4): 1622-1643, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38587931

RESUMO

Genetically encoded fluorescent metal ion sensors are powerful tools for elucidating metal dynamics in living systems. Over the last 25 years since the first examples of genetically encoded fluorescent protein-based calcium indicators, this toolbox of probes has expanded to include other essential and non-essential metal ions. Collectively, these tools have illuminated fundamental aspects of metal homeostasis and trafficking that are crucial to fields ranging from neurobiology to human nutrition. Despite these advances, much of the application of metal ion sensors remains limited to mammalian cells and tissues and a limited number of essential metals. Applications beyond mammalian systems and in vivo applications in living organisms have primarily used genetically encoded calcium ion sensors. The aim of this Perspective is to provide, with the support of historical and recent literature, an updated and critical view of the design and use of fluorescent protein-based sensors for detecting essential metal ions in various organisms. We highlight the historical progress and achievements with calcium sensors and discuss more recent advances and opportunities for the detection of other essential metal ions. We also discuss outstanding challenges in the field and directions for future studies, including detecting a wider variety of metal ions, developing and implementing a broader spectral range of sensors for multiplexing experiments, and applying sensors to a wider range of single- and multi-species biological systems.


Assuntos
Proteínas Luminescentes , Metais , Humanos , Metais/química , Proteínas Luminescentes/química , Animais , Cálcio/análise , Técnicas Biossensoriais/métodos , Corantes Fluorescentes/química , Íons/química , Íons/análise
19.
Talanta ; 274: 125923, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38569366

RESUMO

Mitragyna speciosa, more commonly known as kratom, has emerged as an alternative to treat chronic pain and addiction. However, the alkaloid components of kratom, which are the major contributors to kratom's pharmaceutical properties, have not yet been fully investigated. In this study, matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry was used to map the biodistribution of three alkaloids (corynantheidine, mitragynine, and speciogynine) in rat brain tissues. The alkaloids produced three main ion types during MALDI analysis: [M + H]+, [M - H]+, and [M - 3H]+. Contrary to previous reports suggesting that the [M - H]+ and [M - 3H]+ ion types form during laser ablation, these ion types can also be produced during the MALDI matrix application process. Several strategies are proposed to accurately map the biodistribution of the alkaloids. Due to differences in the relative abundances of the ions in different biological regions of the tissue, differences in ionization efficiencies of the ions, and potential overlap of the [M - H]+ and [M - 3H]+ ion types with endogenous metabolites of the same empirical formula, a matrix that mainly produces the [M + H]+ ion type is optimal for accurate mapping of the alkaloids. Alternatively, the most abundant ion type can be mapped or the intensities of all ion types can be summed together to generate a composite image. The accuracy of each of these approaches is explored and validated.


Assuntos
Alcaloides , Encéfalo , Mitragyna , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Animais , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Mitragyna/química , Ratos , Encéfalo/metabolismo , Encéfalo/diagnóstico por imagem , Alcaloides/farmacocinética , Alcaloides/análise , Alcaloides/química , Masculino , Íons/química , Distribuição Tecidual , Ratos Sprague-Dawley
20.
Int J Biol Macromol ; 266(Pt 2): 131400, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38582480

RESUMO

The aim of the present research is to fabricate a biosorbent using agricultural waste for removal of uranium from contaminated water i.e. "waste to wealth" approach. Cellulose extracted from wheat straw was mercerized and a novel semi-interpenetrating polymer network (semi-IPN) was fabricated through graft copolymerization of polyvinyl alcohol onto hybrid mercerized cellulose + collagen backbone. Response surface methodology was used for optimization of different reaction parameters as a function of % grafting (195.1 %) was carried out. Semi-IPN was found to possess higher thermal stability. Adsorption results revealed that the optimum parameters for the elimination of uranium using semi-IPN were: adsorbent dose = 0.15 g, pH = 6.0, contact time = 120 min and initial U (VI) concentration = 100 µg/L. The pseudo-second-order kinetic model gave the best description of the adsorption equilibrium data as the calculated qe value is nearest to the experimental qe for the different initial U(VI) concentrations. Adsorption experiments followed Langmuir isotherm with R2 = 0.999. Furthermore, recyclability and reusability studies showed that the adsorption efficiency of semi-IPN was 82 % after 5 cycles indicating the superior recycling execution of fabricated biosorbent. Thus, the fabricated ecofriendly device can be used effectively for the removal of uranium from contaminated wastewater sources.


Assuntos
Celulose , Colágeno , Urânio , Purificação da Água , Urânio/química , Celulose/química , Adsorção , Purificação da Água/métodos , Cinética , Colágeno/química , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Temperatura , Íons/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA