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1.
Food Res Int ; 188: 114457, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38823859

ABSTRACT

The effect of the substitution of emulsifying salt by the young bamboo flour (BF) (0, 25, 50, 75, 100 % w/w) on requeijão cremoso processed cheese [REQ, REQ 25, REQ 75 REQ 100]) processing was investigated. Gross composition, calcium and sodium values, functional properties (melting rate), color parameters (L, a*, b*, C*, and Whiteness Index, WI), texture profile, fatty acid profile, volatile organic compounds (VOCs), and sensory profiling were evaluated. No effect was observed on the gross composition; however, sodium and melting rate values were decreased, and calcium values presented the opposite behavior. BF could modify the optical parameters, observing an increase in WI values. Higher BF addition increased hardness and lowered elasticity, and regarding the fatty acid profile, there is no significant difference. Different volatile compounds were noted in a proportional form with the BF addition, which was reflected in similar sensory acceptance for REQ 25 and control samples. Although some aspects require further in-depth studies, using BF as a substitute for emulsifying salt in requeijão cremoso processed cheese appears to be a viable option, especially when considering partial replacements.


Subject(s)
Cheese , Flour , Food Handling , Volatile Organic Compounds , Cheese/analysis , Flour/analysis , Volatile Organic Compounds/analysis , Food Handling/methods , Humans , Taste , Fatty Acids/analysis , Color , Emulsions/chemistry , Hardness , Calcium/analysis , Calcium/chemistry
2.
Food Res Int ; 187: 114329, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38763632

ABSTRACT

The utilization of non-animal-derived materials to imitate cartilage is critical for the advancement of plant-based simulated meat. In this study, gellan gum (GG), konjac glucomannan (KGM), and wheat fiber (WF) were used to construct hydrogel, and the mechanical strength, water properties, and microstructure were regulated by constructing Ca2+ cross-links and moisture control. The hardness, chewiness, resilience, shear force, and shear energy of the Ca2+ cross-linked samples were significantly improved. Extrusion dehydration further changes the related mechanical properties of the hydrogel and results in a tighter microstructure. The findings suggest that the establishment of Ca2+ cross-links and water regulation are efficacious techniques for modifying the texture of the GG/KGM/WF composite hydrogel. Correlation analysis and sensory evaluation showed that the test indexes and sensory scores of the samples with Ca2+ crosslinking and 80 % moisture content were similar to chicken breast cartilage, and the samples with Ca2+ crosslinking and 70 % moisture content were similar to pig crescent bone. This study presents a framework for designing edible cartilage simulators using polysaccharide hydrogels, with implications for enhancing the resemblance of plant-based meat products to real meat and expanding the range of vegetarian offerings available.


Subject(s)
Hydrogels , Mannans , Polysaccharides, Bacterial , Triticum , Polysaccharides, Bacterial/chemistry , Mannans/chemistry , Animals , Hydrogels/chemistry , Triticum/chemistry , Cartilage/chemistry , Water/chemistry , Cross-Linking Reagents/chemistry , Chickens , Calcium/analysis , Calcium/chemistry , Dietary Fiber/analysis
3.
J Phys Chem Lett ; 15(20): 5510-5516, 2024 May 23.
Article in English | MEDLINE | ID: mdl-38749015

ABSTRACT

Viral rhodopsins are light-gated cation channels representing a novel class of microbial rhodopsins. For viral rhodopsin 1 subfamily members VirChR1 and OLPVR1, channel activity is abolished above a certain calcium concentration. Here we present a calcium-dependent spectroscopic analysis of VirChR1 on the femtosecond to second time scale. Unlike channelrhodopsin-2, VirChR1 possesses two intermediate states P1 and P2 on the ultrafast time scale, similar to J and K in ion-pumping rhodopsins. Subsequently, we observe multifaceted photocycle kinetics with up to seven intermediate states. Calcium predominantly affects the last photocycle steps, including the appearance of additional intermediates P6Ca and P7 representing the blocked channel. Furthermore, the photocycle of the counterion variant D80N is drastically altered, yielding intermediates with different spectra and kinetics compared to those of the wt. These findings demonstrate the central role of the counterion within the defined reaction sequence of microbial rhodopsins that ultimately defines the protein function.


Subject(s)
Calcium , Rhodopsins, Microbial , Calcium/chemistry , Calcium/metabolism , Kinetics , Rhodopsins, Microbial/chemistry , Rhodopsins, Microbial/metabolism
4.
J Phys Chem B ; 128(19): 4670-4684, 2024 May 16.
Article in English | MEDLINE | ID: mdl-38717304

ABSTRACT

Ryanodine receptor type 1 (RyR1) is a Ca2+-release channel central to skeletal muscle excitation-contraction (EC) coupling. RyR1's cryo-EM structures reveal a zinc-finger motif positioned within the cytoplasmic C-terminal domain (CTD). Yet, owing to limitations in cryo-EM resolution, RyR1 structures lack precision in detailing the metal coordination structure, prompting the need for an accurate model. In this study, we employed molecular dynamics (MD) simulations and the density functional theory (DFT) method to refine the binding characteristics of Zn2+ in the zinc-finger site of the RyR1 channel. Our findings also highlight substantial conformational changes in simulations conducted in the absence of Zn2+. Notably, we observed a loss of contact at the interface between protein domains proximal to the zinc-finger site, indicating a crucial role of Zn2+ in maintaining structural integrity and interdomain interactions within RyR1. Furthermore, this study provides valuable insights into the modulation of ATP, Ca2+, and caffeine binding, shedding light on the intricate relationship between Zn2+ coordination and the dynamic behavior of RyR1. Our integrative approach combining MD simulations and DFT calculations enhances our understanding of the molecular mechanisms governing ligand binding in RyR1.


Subject(s)
Molecular Dynamics Simulation , Ryanodine Receptor Calcium Release Channel , Zinc , Ryanodine Receptor Calcium Release Channel/chemistry , Ryanodine Receptor Calcium Release Channel/metabolism , Zinc/chemistry , Zinc/metabolism , Ligands , Calcium/chemistry , Calcium/metabolism , Density Functional Theory , Binding Sites , Protein Binding , Zinc Fingers , Caffeine/chemistry , Caffeine/metabolism , Adenosine Triphosphate/chemistry , Adenosine Triphosphate/metabolism , Humans
5.
Nutrients ; 16(9)2024 May 04.
Article in English | MEDLINE | ID: mdl-38732636

ABSTRACT

(1) Background: parenteral nutrition (PN) is indispensable for patients unable to receive oral or enteral feeding. However, the complexity of PN solutions presents challenges regarding stability and compatibility. Precipitation reactions may occur. The most frequent is the formation of calcium phosphate (Ca-P). The different factors influencing these reactions must be considered to ensure patient safety. (2) Methods: eight paediatric PN solutions were prepared, following standard protocols. Samples were stored at room temperature and in a refrigerator. Electron microscopy, coupled with energy dispersive X-ray spectroscopy (EDS), was employed. Precipitates were analysed for composition and morphology. (3) Results: precipitates were observed in all samples, even at day 0. Crystalline structures, predominantly composed of calcium or magnesium, sometimes associated with chlorine or phosphorus, were detected. Additionally, amorphous precipitates, contained heterogeneous compositions, including unexpected elements, were identified. (4) Conclusions: various precipitates, primarily calcium- or magnesium-based, can form in PN solutions, although it is not expected that they can form under the real conditions of use. Calcium oxalate precipitation has been characterised, but the use of organic calcium and phosphate salts appears to mitigate calcium phosphate precipitation. Electron microscopy provides interesting results on NP precipitation, but sample preparation may present technical limitations that affect the interpretation of the results.


Subject(s)
Calcium Phosphates , Chemical Precipitation , Drug Stability , Parenteral Nutrition Solutions , Parenteral Nutrition Solutions/chemistry , Calcium Phosphates/chemistry , Humans , Parenteral Nutrition , Spectrometry, X-Ray Emission , Microscopy, Electron , Magnesium/chemistry , Calcium/chemistry , Calcium/analysis
6.
Int J Biol Macromol ; 270(Pt 1): 132069, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38705333

ABSTRACT

When creating plant-based meat analogs, it is often challenging to mimic the structural and textural attributes of real meat products during the cooking process. In this study, we investigated the potential of using potato protein/calcium alginate composite gels to formulate plant-based meat analogs. These gels provide a semi-solid texture at ambient temperature that remains intact during cooking because the electrostatic crosslinks are resistant to heat. Composite gels consisting of potato protein (10 wt%) and alginate (0-2 wt%) were prepared using the internal gelation method. This method involves dispersing an insoluble form of calcium (CaHPO4) throughout the protein-polysaccharide matrix and then using glucono-delta-lactone (GDL) to slowly lower the pH, thereby releasing the Ca2+ ions evenly throughout the system. The calcium alginate increased the strength of the potato protein gels and provided structural resistance to heat. Appreciable water loss occurred during cooking for simple calcium alginate gels, but this was prevented when potato proteins were present. Increasing the alginate concentration from 0 to 1.5 % increased the strength of the composite gels but higher levels promoted phase separation and network disruption, which reduced the gel strength. Heating did not appreciably alter the microstructure of the composite gels, but it did alter that of the pure potato protein gels. Finally, the potential of the composite gels as plant-based meat analogs was assessed by comparing their thermal denaturation and textural properties to those of real chicken breast. The potato protein/alginate composites were shown to simulate the thermal denaturation and textural changes of real chicken during the cooking process. Overall, our results suggest that calcium alginate gels may be useful in the formulation of plant-based meat products with improved cooking properties.


Subject(s)
Alginates , Calcium , Gels , Plant Proteins , Solanum tuberosum , Alginates/chemistry , Solanum tuberosum/chemistry , Gels/chemistry , Plant Proteins/chemistry , Calcium/chemistry , Meat , Hydrogen-Ion Concentration , Cooking , Animals , Meat Substitutes
7.
Int J Mol Sci ; 25(10)2024 May 13.
Article in English | MEDLINE | ID: mdl-38791360

ABSTRACT

Overly fast corrosion degradation of biodegradable magnesium alloys has been a major problem over the last several years. The development of protective coatings by using biocompatible, biodegradable, and non-toxic material such as chitosan ensures a reduction in the rate of corrosion of Mg alloys in simulated body fluids. In this study, chitosan/TiO2 nanocomposite coating was used for the first time to hinder the corrosion rate of Mg19Zn1Ca alloy in Hank's solution. The main goal of this research is to investigate and explain the corrosion degradation mechanism of Mg19Zn1Ca alloy coated by nanocomposite chitosan-based coating. The chemical composition, structural analyses, and corrosion tests were used to evaluate the protective properties of the chitosan/TiO2 coating deposited on the Mg19Zn1Ca substrate. The chitosan/TiO2 coating slows down the corrosion rate of the magnesium alloy by more than threefold (3.6 times). The interaction of TiO2 (NPs) with the hydroxy and amine groups present in the chitosan molecule cause their uniform distribution in the chitosan matrix. The chitosan/TiO2 coating limits the contact of the substrate with Hank's solution.


Subject(s)
Alloys , Chitosan , Coated Materials, Biocompatible , Magnesium , Titanium , Chitosan/chemistry , Titanium/chemistry , Alloys/chemistry , Corrosion , Magnesium/chemistry , Coated Materials, Biocompatible/chemistry , Zinc/chemistry , Materials Testing , Calcium/chemistry , Nanocomposites/chemistry
8.
Nanoscale ; 16(20): 9935-9943, 2024 May 23.
Article in English | MEDLINE | ID: mdl-38690802

ABSTRACT

Nano/micromotors outperform Brownian motion due to their self-propulsive capabilities and hold promise as carriers for drug delivery across biological barriers such as the extracellular matrix. This study employs poly(2-(diethylamino)ethyl methacrylate) polymer brushes to enhance the collagenase-loading capacity of silica particle-based motors with the aim to systematically investigate the impact of gelatine viscosity, motors' size, and morphology on their propulsion velocity. Notably, 500 nm and 1 µm motors achieve similar speeds as high as ∼15 µm s-1 in stiff gelatine-based hydrogels when triggered with calcium. Taken together, our findings highlight the potential of collagenase-based motors for navigating the extracellular matrix, positioning them as promising candidates for efficient drug delivery.


Subject(s)
Collagenases , Gelatin , Hydrogels , Hydrogels/chemistry , Gelatin/chemistry , Collagenases/metabolism , Collagenases/chemistry , Silicon Dioxide/chemistry , Viscosity , Calcium/chemistry , Calcium/metabolism
9.
Biomed Mater ; 19(4)2024 May 31.
Article in English | MEDLINE | ID: mdl-38772387

ABSTRACT

Single-cell analysis is an effective method for conducting comprehensive heterogeneity studies ranging from cell phenotype to gene expression. The ability to arrange different cells in a predetermined pattern at single-cell resolution has a wide range of applications in cell-based analysis and plays an important role in facilitating interdisciplinary research by researchers in various fields. Most existing microfluidic microwell chips is a simple and straightforward method, which typically use small-sized microwells to accommodate single cells. However, this method imposes certain limitations on cells of various sizes, and the single-cell capture efficiency is relatively low without the assistance of external forces. Moreover, the microwells limit the spatiotemporal resolution of reagent replacement, as well as cell-to-cell communication. In this study, we propose a new strategy to prepare a single-cell array on a planar microchannel based on microfluidic flip microwells chip platform with large apertures (50 µm), shallow channels (50 µm), and deep microwells (50 µm). The combination of three configuration characteristics contributes to multi-cell trapping and a single-cell array within microwells, while the subsequent chip flipping accomplishes the transfer of the single-cell array to the opposite planar microchannel for cells adherence and growth. Further assisted by protein coating of bovine serum albumin and fibronectin on different layers, the single-cell capture efficiency in microwells is achieved at 92.1% ± 1%, while ultimately 85% ± 3.4% on planar microchannel. To verify the microfluidic flip microwells chip platform, the real-time and heterogeneous study of calcium release and apoptosis behaviours of single cells is carried out. To our knowledge, this is the first time that high-efficiency single-cell acquisition has been accomplished using a circular-well chip design that combines shallow channel, large aperture and deep microwell together. The chip is effective in avoiding the shearing force of high flow rates on cells, and the large apertures better allows cells to sedimentation. Therefore, this strategy owns the advantages of easy preparation and user-friendliness, which is especially valuable for researchers from different fields.


Subject(s)
Microfluidics , Single-Cell Analysis , Single-Cell Analysis/methods , Humans , Microfluidics/methods , Cell Adhesion , Animals , Equipment Design , Microfluidic Analytical Techniques/instrumentation , Lab-On-A-Chip Devices , Fibronectins/chemistry , Fibronectins/metabolism , Calcium/metabolism , Calcium/chemistry , Serum Albumin, Bovine/chemistry , Cell Communication
10.
Sci Rep ; 14(1): 9786, 2024 04 29.
Article in English | MEDLINE | ID: mdl-38684921

ABSTRACT

Hydroxyapatite (HAP) constitutes the primary mineral component of bones, and its crystal structure, along with the surface interaction with proteins, significantly influences the outstanding mechanical properties of bone. This study focuses on natural hydroxyapatite, constructing a surface model with calcium vacancy defects. Employing a representative model of aspartic acid residues, we delve into the adsorption mechanism on the crystal surface and scrutinize the adsorption forms of amino acid residues on HAP and calcium-deficient hydroxyapatite (CDHA) surfaces. The research also explores the impact of different environments on adsorption energy. Furthermore, a simplified sandwich structure of crystal-polypeptide-crystal is presented, analyzing the distribution of amino acid residue adsorption sites on the crystal surface of the polypeptide fragment. This investigation aims to elucidate how the stick-slip mechanism of polypeptide molecules on the crystal surface influences the mechanical properties of the system. By uncovering the interface mechanical behavior between HAP and osteopontin peptides, this article offers valuable theoretical insights for the construction and biomimetic design of biocomposites.


Subject(s)
Bone and Bones , Durapatite , Osteopontin , Durapatite/chemistry , Bone and Bones/metabolism , Bone and Bones/chemistry , Osteopontin/chemistry , Osteopontin/metabolism , Adsorption , Peptides/chemistry , Peptides/metabolism , Humans , Models, Molecular , Protein Binding , Crystallization , Surface Properties , Calcium/metabolism , Calcium/chemistry
11.
J Environ Manage ; 358: 120894, 2024 May.
Article in English | MEDLINE | ID: mdl-38643621

ABSTRACT

Discharging improperly treated oily-produced water (OPW) into the environment can have significant negative impacts on environmental sustainability. It can lead to pollution of water sources, damage to aquatic ecosystems and potential health hazards for individuals living in the affected areas. Ceramic hollow fiber membrane (CHFM) technology is one of the most effective OPW treatment methods for achieving high oil removal efficiency while maintaining membrane water permeability. In this study, low-cost calcium bentonite hollow fiber membranes (CaB-HFMs) were prepared from high-alumina calcium bentonite clay with various preparation parameters, including calcium bentonite content, sintering temperature, air gap distance and bore fluid rate. The prepared CaB-HFMs were then subjected to characterization using scanning electron microscopy (SEM), a three-point bending test, porosity, average pore size, hydraulic resistance and flux recovery ratio (FRR) analysis. Statistical analysis employing central composite design (CCD) assessed the interaction between the parameters and their effect on CaB-HFM water permeability and oil removal efficiency. Higher ceramic content and sintering temperature led to reduced porosity, smaller pore size and higher mechanical strength. In contrast, increasing the air gap distance and bore fluid rate exhibit different trends, resulting in higher porosity and pore size, along with weaker mechanical strength. Other than that, all of the CaB-HFMs displayed low hydraulic resistance (<0.01 m2 h.bar/L) and high FRR value (up to 95.2%). Based on CCD, optimal conditions for CaB-HFM were determined as follows: a calcium bentonite content of 50 wt.%, a sintering temperature of 1096 °C, an air gap distance of 5 cm and a bore fluid rate of 10 mL/min, with the desirability value of 0.937. Notably, the optimized CaB-HFMs demonstrated high oil removal efficiency of up to 99.7% with exceptional water permeability up to 535.2 L/m2.h.bar. The long-term permeation study also revealed it was capable of achieving a high average water permeation and a stable oil rejection performance of 522.15 L/m2.h.bar and 99.8%, respectively, due to their inherent hydrophilic and antifouling characteristics, making it practical for OPW treatment application.


Subject(s)
Bentonite , Bentonite/chemistry , Salinity , Permeability , Calcium/chemistry , Membranes, Artificial
12.
Chemosphere ; 357: 142070, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38641297

ABSTRACT

Calcium (Ca2+) and phosphorous (PO43-) significantly influence the form and effectiveness of nitrogen (N), however, the precise mechanisms governing the adsorption of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) are still lacking. This study employed batch adsorption experiments, charge distribution and multi-site complexation (CD-MUSIC) models and density functional theory (DFT) calculations to elucidate the mechanism by which Ca2+ and PO43- affect the adsorption of NH4+-N and NO3--N on the goethite (GT) surface. The results showed that the adsorption of NH4+-N on the GT exhibited an initial increase followed by a decrease as pH increased, peaking at a pH of 8.5. Conversely, the adsorption of NO3--N decreased with rising pH. According to the CD-MUSIC model, Ca2+ minimally affected the NH4+-N adsorption on the GT but enhanced NO3--N adsorption via electrostatic interaction, promoting the adsorption of ≡FeOH-NO3- and ≡Fe3O-NO3- species. Similarly, PO43- inhibited the adsorption of ≡FeOH-NO3- and ≡Fe3O-NO3- species. However, PO43- boosted NH4+-N adsorption by facilitating the formation of ≡Fe3O-NH4+ via electrostatic interaction and site competition. DFT calculations indicates that although bidentate phosphate (BP) was beneficial to stabilize NH4+-N than monodentate phosphate (SP), SP-NH4+ was the main adsorption configuration at pH 5.5-9.5 owing the prevalence of SP on the GT surface under site competition of NH4+-N. The results of CD-MUSIC model and DFT calculation were verified mutually, and provide novel insights into the mechanisms underlying N fixation and migration in soil.


Subject(s)
Ammonium Compounds , Calcium , Density Functional Theory , Nitrates , Nitrogen , Phosphorus , Adsorption , Calcium/chemistry , Nitrogen/chemistry , Phosphorus/chemistry , Nitrates/chemistry , Ammonium Compounds/chemistry , Ferric Compounds/chemistry , Models, Chemical , Hydrogen-Ion Concentration
13.
Nanotechnology ; 35(30)2024 May 10.
Article in English | MEDLINE | ID: mdl-38663375

ABSTRACT

In this research, we utilize porous tantalum, known for its outstanding elastic modulus and biological properties, as a base material in biomedical applications. The human skeletal system is rich in elements like Ca and Zn. The role of Zn is crucial for achieving a spectrum of sterilizing effects, while Ca is known to effectively enhance cell differentiation and boost cellular activity. The focus of this study is the modification of porous tantalum using a hydrothermal method to synthesize Ca2+/Zn2+-doped Ta2O5nanorods. These nanorods are subjected to extensive characterization techniques to confirm their structure and composition. Additionally, their biological performance is evaluated through a range of tests, including antibacterial assessments, MTT assays, and bacteria/cell scanning electron microscopy (SEM) analyses. The objective is to determine the most effective method of surface modification for porous tantalum, thereby laying a foundational theoretical framework for its surface enhancement.


Subject(s)
Anti-Bacterial Agents , Calcium , Tantalum , Zinc , Tantalum/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Zinc/chemistry , Zinc/pharmacology , Calcium/chemistry , Humans , Staphylococcus aureus/drug effects , Surface Properties , Porosity , Escherichia coli/drug effects , Microbial Sensitivity Tests
14.
Colloids Surf B Biointerfaces ; 238: 113880, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38581836

ABSTRACT

In the field of orthopedics, it's crucial to effectively slow down the degradation rate of Mg alloys. This study aims to improve the degradation behavior of Mg-Zn-Ca alloys by electrodepositing fluorohydroxyapatite (FHA). We investigated the microstructure and bond strength of the deposition, as well as degradation and cellular reactions. After 15-30 days of degradation in Hanks solution, FHA deposited alloys showed enhanced stability and less pH change. The strong interfacial bond between FHA and the Mg-Zn-Ca substrate was verified through scratch tests (Critical loads: 10.73 ± 0.014 N in Mg-Zn-0.5Ca alloys). Cellular studies demonstrated that FHA-coated alloys exhibited good cytocompatibility and promoted the growth of MC3T3-E1 cells. Further tests showed FHA-coated alloys owed improved early bone mineralization and osteogenic properties, especially in Mg-Zn-0.5Ca. This research highlighted the potential of FHA-coated Mg-Zn-0.5Ca alloys in orthopedics applications.


Subject(s)
Alloys , Calcium , Magnesium , Zinc , Alloys/chemistry , Alloys/pharmacology , Corrosion , Animals , Zinc/chemistry , Zinc/pharmacology , Magnesium/chemistry , Mice , Calcium/chemistry , Calcium/metabolism , Coated Materials, Biocompatible/chemistry , Coated Materials, Biocompatible/pharmacology , Surface Properties , Materials Testing , Cell Proliferation/drug effects , Hydroxyapatites/chemistry , Cell Line , Durapatite/chemistry , Durapatite/pharmacology
15.
Anal Chim Acta ; 1305: 342590, 2024 May 29.
Article in English | MEDLINE | ID: mdl-38677844

ABSTRACT

Monitoring extracellular calcium ion (Ca2+) chemical signals in neurons is crucial for tracking physiological and pathological changes associated with brain diseases in live animals. Potentiometry based solid-state ion-selective electrodes (ISEs) with the assist of functional carbon nanomaterials as ideal solid-contact layer could realize the potential response for in vitro and in vivo analysis. Herein, we employ a kind of biomass derived porous carbon as a transducing layer to prompt efficient ion to electron transduction while stabilizes the potential drift. The eco-friendly porous carbon after activation (APB) displays a high specific area with inherit macropores, micropores, and large specific capacitance. When employed as transducer in ISEs, a stable potential response, minimized potential drift can be obtained. Benefiting from these excellent properties, a solid-state Ca2+ selective carbon fiber electrodes (CFEs) with a sandwich structure is constructed and employed for real time sensing of Ca2+ under electrical stimulation. This study presents a new approach to develop sustainable and versatile transducers in solid-state ISEs, a crucial way for in vivo sensing.


Subject(s)
Calcium , Carbon , Nanostructures , Calcium/chemistry , Calcium/analysis , Carbon/chemistry , Nanostructures/chemistry , Ion-Selective Electrodes , Animals , Porosity , Transducers , Electrochemical Techniques/instrumentation
16.
Environ Sci Pollut Res Int ; 31(20): 29836-29858, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38592627

ABSTRACT

Indirect carbonation of steel slag is an effective method for CO2 storage, reducing emissions, and promoting cleaner production in the steel industry. However, challenges remain, such as low Ca2+ leaching rates and slag management complexities arising from variations in mineral compositions. To address this, a high-temperature modification process is proposed to alter the mineral composition and facilitate the synergistic utilization of calcium and iron. This study delves into the effects of various solid waste modifications on the leaching of Ca2+ and the total iron content within steel slag. Results show that high-basicity modified slag forms Ca2(Al, Fe)2O5, reducing calcium leaching. Low-alkalinity modified slag produces calcium-rich aluminum minerals and also reduces the leaching of Ca2+ ions. At a basicity of 2.5, coal gangue, fly ash, and blast slag achieve maximum Ca2+ leaching rates of 88.93%, 89.46%, and 90.17%, respectively, with corresponding total iron contents of 41.46%, 37.72%, and 35.29%. Upgraded coal gangue exhibits a 50.02% increase in calcium leaching and a 15.58% increase in total iron content compared to the original slag. This enhances CO2 fixation and iron resource utilization. Overall, the proposed indirect carbonation and iron enrichment modification offer a novel approach for the resource utilization and environmental stability of steel slag.


Subject(s)
Calcium , Solid Waste , Steel , Calcium/chemistry , Iron/chemistry , Hot Temperature
17.
J Phys Chem B ; 128(16): 3870-3884, 2024 Apr 25.
Article in English | MEDLINE | ID: mdl-38602496

ABSTRACT

The O2-evolving Mn4CaO5 cluster in photosystem II is ligated by six carboxylate residues. One of these is D170 of the D1 subunit. This carboxylate bridges between one Mn ion (Mn4) and the Ca ion. A second carboxylate ligand is D342 of the D1 subunit. This carboxylate bridges between two Mn ions (Mn1 and Mn2). D170 and D342 are located on opposite sides of the Mn4CaO5 cluster. Recently, it was shown that the D170E mutation perturbs both the intricate networks of H-bonds that surround the Mn4CaO5 cluster and the equilibrium between different conformers of the cluster in two of its lower oxidation states, S1 and S2, while still supporting O2 evolution at approximately 50% the rate of the wild type. In this study, we show that the D342E mutation produces much the same alterations to the cluster's FTIR and EPR spectra as D170E, while still supporting O2 evolution at approximately 20% the rate of the wild type. Furthermore, the double mutation, D170E + D342E, behaves similarly to the two single mutations. We conclude that D342E alters the equilibrium between different conformers of the cluster in its S1 and S2 states in the same manner as D170E and perturbs the H-bond networks in a similar fashion. This is the second identification of a Mn4CaO5 metal ligand whose mutation influences the equilibrium between the different conformers of the S1 and S2 states without eliminating O2 evolution. This finding has implications for our understanding of the mechanism of O2 formation in terms of catalytically active/inactive conformations of the Mn4CaO5 cluster in its lower oxidation states.


Subject(s)
Carboxylic Acids , Mutation , Oxygen , Photosystem II Protein Complex , Calcium/metabolism , Calcium/chemistry , Carboxylic Acids/chemistry , Carboxylic Acids/metabolism , Electron Spin Resonance Spectroscopy , Ligands , Manganese/chemistry , Manganese/metabolism , Models, Molecular , Oxygen/chemistry , Oxygen/metabolism , Photosystem II Protein Complex/chemistry , Photosystem II Protein Complex/metabolism , Photosystem II Protein Complex/genetics , Spectroscopy, Fourier Transform Infrared
18.
Int J Biol Macromol ; 266(Pt 2): 131313, 2024 May.
Article in English | MEDLINE | ID: mdl-38569997

ABSTRACT

In recent years, considerable attention has been given to the utilization of biomass for producing bio-based foams, such as starch-based foams. Despite their renewability and widespread availability, these foams still present certain drawbacks regarding their poor mechanical properties and flammability. To tackle these concerns, a metal ion cross-linking strategy was employed by incorporating calcium ions (Ca2+) solution into foamed starch/cellulose slurry. Followed by ambient drying, starch/cellulose composite foam was successfully fabricated with a remarkable enhancement in various properties. Specifically, compared to the control sample, the compressive strength and modulus increased by 26.2 % and 123.0 %, respectively. Additionally, the Ca2+ cross-linked starch/cellulose composite foam exhibited excellent heat resistance, water stability, and flame retardancy. The limiting oxygen index (LOI) reached 52 %, with a vertical combustion rating of V-0. Along with the addition of 2 phr diatomite, it demonstrated a significant enhancement on flame retardancy with a LOI of 65 %, although the apparent density of the composite foam was not low enough. This study indicated a green and simple method to obtain starch-based composite foams with enhanced comprehensive properties including thermal, water stability, mechanical, and flame retardancy, expanding their potential applications in areas such as building materials and rigid packaging.


Subject(s)
Cellulose , Diatomaceous Earth , Flame Retardants , Starch , Cellulose/chemistry , Starch/chemistry , Diatomaceous Earth/chemistry , Compressive Strength , Water/chemistry , Calcium/chemistry
19.
Food Chem ; 451: 139268, 2024 Sep 01.
Article in English | MEDLINE | ID: mdl-38663247

ABSTRACT

Calcium-chelating peptides were found in Pacific cod bone, but their binding structure and properties have not been elucidated. Novel calcium-binding peptides were isolated by hydroxyapatite affinity chromatography (HAC), and their binding structure and properties were investigated by isothermal titration calorimetry (ITC), multispectral techniques, and mass spectrometry. Based on multiple purifications, the calcium binding capacity (CBC) of Pacific cod bone peptides (PBPs) was increased from 1.71 ± 0.15 µg/mg to 7.94 ± 1.56 µg/mg. Peptides with a molecular weight of 1-2 kDa are closely correlated with CBC. After binding to calcium, the secondary structure of peptides transitioned from random coil to ß-sheet, resulting in a loose and porous microstructure. Hydrogen bonds, electrostatic interaction, and hydrophobic interaction contribute to the formation of peptide­calcium complexes. The F21 contained 42 peptides, with repeated "GE" motif. Differential structure analysis provides a theoretical basis for the targeted preparation of high CBC peptides.


Subject(s)
Bone and Bones , Calcium , Durapatite , Fish Proteins , Peptides , Animals , Durapatite/chemistry , Bone and Bones/chemistry , Calcium/chemistry , Fish Proteins/chemistry , Peptides/chemistry , Peptides/isolation & purification , Chromatography, Affinity , Calcium-Binding Proteins/chemistry , Calcium-Binding Proteins/metabolism , Calcium-Binding Proteins/isolation & purification , Protein Binding , Amino Acid Sequence , Gadiformes , Protein Structure, Secondary
20.
Bioprocess Biosyst Eng ; 47(5): 753-766, 2024 May.
Article in English | MEDLINE | ID: mdl-38573334

ABSTRACT

Green synthesis of metal oxides as a treatment for bone diseases is still exploring. Herein, MgO and Fe2O3 NPs were prepared from the extract of Hibiscus sabdariffa L. to study their effect on vit D3, Ca+2, and alkaline phosphatase enzyme ALP associated with osteoporosis. Computational chemistry was utilized to gain insight into the possible interactions. These oxides were characterized by X-ray diffraction, SEM, FTIR, and AFM. Results revealed that green synthesis of MgO and Fe2O3 NPs was successful with abundant. MgO NPs were in vitro applied on osteoporosis patients (n = 35) and showed a significant elevation of vit D3 and Ca+2 (0.0001 > p < 0.001) levels, compared to healthy volunteers (n = 25). Thus, Hibiscus sabdariffa L. is a good candidate to prepare MgO NPs, with a promising enhancing effect on vit D3 and Ca+2 in osteoporosis. In addition, interactions of Fe2O3 and MgO NPs with ALP were determined by molecular docking study.


Subject(s)
Hibiscus , Magnesium Oxide , Osteoporosis , Hibiscus/chemistry , Humans , Osteoporosis/drug therapy , Magnesium Oxide/chemistry , Ferric Compounds/chemistry , Plant Extracts/chemistry , Female , Male , Calcium/chemistry , Molecular Docking Simulation , Metal Nanoparticles/chemistry , Middle Aged , Oxides/chemistry , Alkaline Phosphatase/metabolism , Cholecalciferol/chemistry , Cholecalciferol/pharmacology
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