10,533 results match your criteria aggregation kinetics

Modeling Amyloid Aggregation Kinetics: A Case Study with Sup35NM.

J Phys Chem B 2021 May 7. Epub 2021 May 7.

School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.

Understanding the aggregation mechanism of amyloid proteins, such as Sup35NM, is essential to understanding amyloid diseases. Significant recent work has focused on using the fluorescence of thioflavin T (ThT), which undergoes a red shift when bound to amyloid aggregates, to monitor amyloid fibril formation. In the present study, the progression of the total mass of aggregates during fibril formation is monitored for initial monomer concentrations in order to infer the relevant aggregation mechanisms. Read More

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Effect of spin labelling on the aggregation kinetics of yeast prion protein Ure2.

R Soc Open Sci 2021 Mar 3;8(3):201747. Epub 2021 Mar 3.

Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA.

Amyloid formation is involved in a wide range of neurodegenerative diseases including Alzheimer's and prion diseases. Structural understanding of the amyloid is critical to delineate the mechanism of aggregation and its pathological spreading. Site-directed spin labelling has emerged as a powerful structural tool in the studies of amyloid structures and provided structural evidence for the parallel in-register β-sheet structure for a wide range of amyloid proteins. Read More

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A semi dynamic digestion study of milk protein concentrate dispersions structured with different polysaccharides.

Curr Res Food Sci 2021 6;4:250-261. Epub 2021 Apr 6.

Department of Food Science, CiFood Multidisciplinary Center, Aarhus University, 48 Agro Food Park, Aarhus N, 8200, Denmark.

Hydrocolloids are often added as functional ingredients in foods, to better design the structure of the matrix and ensure food quality and optimal sensory properties. However, much less is known about their influence on the physical and chemical changes during gastric digestion. In this study, semi-continuous gastric digestion was applied on a model food system, prepared with milk protein concentrate (MPC) (3% w/v) and 1% alginate, pectin, guar gum, as well as a 1:1 mixture of alginate and pectin. Read More

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Are Smaller Nanoparticles Always Better? Understanding the Biological Effect of Size-Dependent Silver Nanoparticle Aggregation Under Biorelevant Conditions.

Int J Nanomedicine 2021 23;16:3021-3040. Epub 2021 Apr 23.

Department of Applied and Environmental Chemistry, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.

Purpose: Silver nanoparticles (AgNPs) are one of the most commonly investigated nanomaterials, especially due to their biomedical applications. However, their excellent cytotoxic and antimicrobial activity is often compromised in biological media due to nanoparticle aggregation. In this work, the aggregation behavior and the related biological activity of three different samples of citrate capped silver nanoparticles, with mean diameters of 10, 20, and 50 nm, respectively, were examined. Read More

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Effect of root exudates on the stability and transport of graphene oxide in saturated porous media.

J Hazard Mater 2021 Jul 17;413:125362. Epub 2021 Feb 17.

Key Laboratory of Surficial Geochemistry of Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing 210023, China.

Root exudates are a major source of dissolved organic matters that strongly affect the stability and transport behaviors of nanomaterials in porous media. This study investigated the effect of citric acid (CA) and oxalic acid (OA), two common low molecular weight root exudates, on the stability and transport of graphene oxide (GO) in saturated sand columns under different combinations of pH (4.5, 7. Read More

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Electrochemical Characterization of Aromatic Molecules with 1,4-Diaza Groups for Flow Battery Applications.

Molecules 2021 Apr 12;26(8). Epub 2021 Apr 12.

Department of Energy Conversion and Storage, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.

The aqueous redox flow battery is a promising technology for large-scale low cost energy storage. The rich possibilities for the tailoring of organic molecules and the possibility to discover active materials of lower cost and decreased environmental impact continue to drive research and development of organic compounds suitable for redox flow battery applications. In this work, we focus on the characterization of aromatic molecules with 1,4-diaza groups for flow battery applications. Read More

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Effect of Surface Roughness on Aggregation of Polypeptide Chains: A Monte Carlo Study.

Biomolecules 2021 Apr 18;11(4). Epub 2021 Apr 18.

Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland.

The self-assembly of amyloidogenic peptides and proteins into fibrillar structures has been intensively studied for several decades, because it seems to be associated with a number of neurodegenerative diseases, such as Alzheimer's and Parkinson's disease. Therefore, understanding the molecular mechanisms of this phenomenon is important for identifying an effective therapy for the corresponding diseases. Protein aggregation in living organisms very often takes place on surfaces like membranes and the impact of a surface on this process depends not only on the surface chemistry but also on its topology. Read More

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Cellular Automata Modeling of Silica Aerogel Condensation Kinetics.

Gels 2021 Apr 21;7(2). Epub 2021 Apr 21.

Faculty of Chemical and Process Engineering, Warsaw University of Technology, 00-645 Warsaw, Poland.

The formation of silica aerogels and the kinetics of condensation were investigated numerically. The influence of the reaction-limited to the diffusion-limited aggregation (RLA to DLA) transition on the reaction kinetics curves and the evolution of the aggregate size distribution during condensation were examined. The 2D cellular automaton was developed and applied to reflect the process of secondary particle aggregation. Read More

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Liquid-Liquid Phase Separation Enhances TDP-43 LCD Aggregation but Delays Seeded Aggregation.

Biomolecules 2021 Apr 8;11(4). Epub 2021 Apr 8.

Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), KU Leuven-University of Leuven, 3000 Leuven, Belgium.

Aggregates of TAR DNA-binding protein (TDP-43) are a hallmark of several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). Although TDP-43 aggregates are an undisputed pathological species at the end stage of these diseases, the molecular changes underlying the initiation of aggregation are not fully understood. The aim of this study was to investigate how phase separation affects self-aggregation and aggregation seeded by pre-formed aggregates of either the low-complexity domain (LCD) or its short aggregation-promoting regions (APRs). Read More

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Influence of pH, Temperature and Protease Inhibitors on Kinetics and Mechanism of Thermally Induced Aggregation of Potato Proteins.

Foods 2021 Apr 8;10(4). Epub 2021 Apr 8.

Food and Bioprocess Engineering, TUM School of Life Sciences, Technical University of Munich, Weihenstephaner Berg 1, 85354 Freising, Germany.

Understanding aggregation in food protein systems is essential to control processes ranging from the stabilization of colloidal dispersions to the formation of macroscopic gels. Patatin rich potato protein isolates (PPI) have promising techno-functionality as alternatives to established proteins from egg white or milk. In this work, the influence of pH and temperature on the kinetics of PPI denaturation and aggregation was investigated as an option for targeted functionalization. Read More

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Dimerization Drives Proper Folding of Human Alanine:Glyoxylate Aminotransferase But Is Dispensable for Peroxisomal Targeting.

J Pers Med 2021 Apr 6;11(4). Epub 2021 Apr 6.

Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy.

Peroxisomal matrix proteins are transported into peroxisomes in a fully-folded state, but whether multimeric proteins are imported as monomers or oligomers is still disputed. Here, we used alanine:glyoxylate aminotransferase (AGT), a homodimeric pyridoxal 5'-phosphate (PLP)-dependent enzyme, whose deficit causes primary hyperoxaluria type I (PH1), as a model protein and compared the intracellular behavior and peroxisomal import of native dimeric and artificial monomeric forms. Monomerization strongly reduces AGT intracellular stability and increases its aggregation/degradation propensity. Read More

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A Potential Role for Fructosamine-3-Kinase in Cataract Treatment.

Int J Mol Sci 2021 Apr 7;22(8). Epub 2021 Apr 7.

Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium.

Cataracts are the major cause of blindness worldwide, largely resulting from aging and diabetes mellitus. Advanced glycation end products (AGEs) have been identified as major contributors in cataract formation because they alter lens protein structure and stability and induce covalent cross-linking, aggregation, and insolubilization of lens crystallins. We investigated the potential of the deglycating enzyme fructosamine-3-kinase (FN3K) in the disruption of AGEs in cataractous lenses. Read More

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In Vitro and In Silico Screening and Characterization of Antimicrobial Napin Bioactive Protein in and .

Molecules 2021 Apr 5;26(7). Epub 2021 Apr 5.

Department of Food Science and Biotechnology, College of Agriculture and Life Science, Kangwon National University, Chuncheon 24341, Korea.

The study aimed to investigate the antibacterial activity of Mustard () and Moringa () leaf extracts and coagulant protein for their potential application in water treatment. Bacterial cell aggregation and growth kinetics studies were employed for thirteen bacterial strains with different concentrations of leaf extracts and coagulant protein. leaf extract (MOS) and coagulant protein showed cell aggregation against ten bacterial strains, whereas leaf extract alone showed growth inhibition of five bacterial strains for up to 6 h and five bacterial strains for up to 3 h. Read More

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Aggregation and Deposition Kinetics of Polystyrene Microplastics and Nanoplastics in Aquatic Environment.

Bull Environ Contam Toxicol 2021 Apr 29. Epub 2021 Apr 29.

Environment Research Institute, Shandong University, Qingdao, 266237, China.

Microplastics (MPs) and nanoplastics (NPs) attract widespread attention due to their final threats to human health. Here, 50 nm and 500 nm polystyrene particles (PS50 and PS500) were selected as the typical NPs and MPs, respectively. Their aggregation kinetics was monitored, and their deposition was investigated on silica and alumina surfaces using quartz crystal microbalance with dissipation monitoring (QCM-D). Read More

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Tau/Aβ chimera peptides: A Thioflavin-T and MALDI-TOF study of Aβ amyloidosis in the presence of Cu(II) or Zn(II) ions and total lipid brain extract (TLBE) vesicles.

Chem Phys Lipids 2021 Apr 22;237:105085. Epub 2021 Apr 22.

Istituto di Cristallografia S.S. di Catania, Via P. Gaifami 18, 95126, Catania, Italy. Electronic address:

Currently, Alzheimer's Disease (AD) is a complex neurodegenerative condition, with limited therapeutic options. Several factors, like Amyloid β (Aβ) aggregation, tau protein hyperphosphorylation, bio-metals dyshomeostasis and oxidative stress contribute to AD pathogenesis. These pathogenic processes might occur in the aqueous phase but also on neuronal membranes. Read More

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Continuous Monitoring of Tau-Induced Neurotoxicity in Patient-Derived iPSC-Neurons.

J Neurosci 2021 Apr 20. Epub 2021 Apr 20.

Harvard Medical School, Boston, Massachusetts 02115.

Tau aggregation within neurons is a critical feature of Alzheimer's disease (AD) and related tauopathies. It is believed that soluble pathologic tau species seed the formation of tau aggregates in a prion-like manner and propagate through connected neurons during the progression of disease. Both soluble and aggregated forms of tau are thought to have neurotoxic properties. Read More

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Stability of Boron Nitride Nanosphere Dispersions in the Presence of Polyelectrolytes.

Langmuir 2021 May 20;37(17):5399-5407. Epub 2021 Apr 20.

Interdisciplinary Excellence Center, Department of Applied and Environmental Chemistry, University of Szeged, Szeged H-6720, Hungary.

Boron nitride nanospheres (BNNSs) were functionalized with polyelectrolytes. The effect of the polyelectrolyte dose and ionic strength on the charging and aggregation properties was investigated. At appropriate polyelectrolyte doses, charge neutralization occurred, whereas by increasing the dose, charge reversal was observed. Read More

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Hybridization-based design of novel anticholinesterase indanone-carbamates for Alzheimer's disease: Synthesis, biological evaluation, and docking studies.

Arch Pharm (Weinheim) 2021 Apr 19:e2000453. Epub 2021 Apr 19.

Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.

Inspired by the structures of donepezil and rivastigmine, a novel series of indanone-carbamate hybrids was synthesized using the pharmacophore hybridization-based design strategy, and their biological activities toward acetylcholinesterase (AChE) and butyrylcholinesterase were evaluated. Among the synthesized compounds, 4d and 4b showed the highest AChE inhibitory activities with IC values in the micromolar range (compound 4d: IC  = 3.04 μM; compound 4b: IC  = 4. Read More

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Degradation of Alzheimer's amyloid-β by a catalytically inactive insulin-degrading enzyme.

J Mol Biol 2021 Apr 15:166993. Epub 2021 Apr 15.

Biophysics, Department of Chemistry, Macromolecular Engineering and Science, and Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. Electronic address:

It is known that insulin-degrading-enzyme (IDE) plays a crucial role in the clearance of Alzheimer's amyloid-β (Aβ). The cysteine-free IDE mutant (cf-E111Q-IDE) is catalytically inactive against insulin, but its effect on Aβ degradation is unknown that would help in the allosteric modulation of the enzyme activity. Herein, the degradation of Aβ(1-40) by cf-E111Q-IDE via a non-chaperone mechanism is demonstrated by NMR and LC-MS, and the aggregation of fragmented peptides is characterized using fluorescence and electron microscopy. Read More

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Non-phosphorylated Tau slows down Aβ aggregation, binds to Aβ oligomers and reduces Aβ toxicity.

J Biol Chem 2021 Apr 15:100664. Epub 2021 Apr 15.

Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, 20156 Milan, Italy. Electronic address:

The formation of neurofibrillary tangles and amyloid plaques accompanies the progression of Alzheimer's disease (AD). Tangles are made of fibrillar aggregates formed by the microtubule-associated protein tau, while plaques comprise fibrillar forms of amyloid-β (Aβ). Both form toxic oligomers during aggregation, and are thought to interact synergistically to each promote the accumulation of the other. Read More

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MXene-Derived Ti O Quantum Dots Distributed on Porous Carbon Nanosheets for Stable and Long-Life Li-S Batteries: Enhanced Polysulfide Mediation via Defect Engineering.

Adv Mater 2021 Apr 17:e2008447. Epub 2021 Apr 17.

Key Laboratory of Advanced Metallic Materials of Jiangsu Province, School of Materials Science and Engineering, Southeast University, Nanjing, 211189, P. R. China.

The application of Li-S batteries has been hindered by the shuttling behavior and sluggish reaction kinetics of polysulfides. Here an effective polysulfide immobilizer and catalytic promoter is developed by proposing oxygen-vacancy-rich Ti O quantum dots (OV-T QDs) decorated on porous carbon nanosheets (PCN), which are modulated using Ti C T MXene as starting materials. The T QDs not only confine polysulfides through strong chemisorption but also promote polysulfide conversion via redox-active catalysis. Read More

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Pancreastatin induces islet amyloid peptide aggregation in the pancreas, liver, and skeletal muscle: An implication for type 2 diabetes.

Int J Biol Macromol 2021 Apr 16;182:760-771. Epub 2021 Apr 16.

Pharmaceutics & Pharmacokinetics, CSIR-Central Drug Research Institute, Sitapur Road, Lucknow 226031, India; Pharmacology Division, CSIR-Central Drug Research Institute, Sitapur Road, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, Uttar Pradesh, India. Electronic address:

Recent findings suggest that the accumulation of misfolded aggregates of islet amyloid peptide (IAPP) plays an essential role in pancreatic damage and type 2 diabetes (T2D). Pancreastatin (PST), a chromogranin derived peptide, instigates insulin resistance (IR) and promotes T2D. Here, we aimed to investigate whether PST induces IAPP aggregation in the pancreas, liver, and skeletal muscles. Read More

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A study of Pb induced unfolding and aggregation of arginine kinase from : kinetics and computational simulation integrating study.

J Biomol Struct Dyn 2021 Apr 13:1-10. Epub 2021 Apr 13.

College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, P.R. China.

Arginine kinase is a crucial phosphagen kinase in invertebrates, which is associated to the environmental stress response, plays a key role in cellular energy metabolism. In this study, we investigated the Pb-induced inhibition and aggregation of arginine kinase (ESAK) and found that significantly inactivated ESAK in a dose-dependent manner (50 = 0.058 ± 0. Read More

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Kinetic analysis reveals that independent nucleation events determine the progression of polyglutamine aggregation in .

Proc Natl Acad Sci U S A 2021 Mar;118(11)

Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208-3500;

Protein aggregation is associated with a wide range of degenerative human diseases with devastating consequences, as exemplified by Alzheimer's, Parkinson's, and Huntington's diseases. In vitro kinetic studies have provided a mechanistic understanding of the aggregation process at the molecular level. However, it has so far remained largely unclear to what extent the biophysical principles of amyloid formation learned in vitro translate to the complex environment of living organisms. Read More

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Tryptophan Probes of TDP-43 C-Terminal Domain Amyloid Formation.

J Phys Chem B 2021 Apr 9;125(15):3781-3789. Epub 2021 Apr 9.

Laboratory of Protein Conformation and Dynamics, Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States.

Aggregated TAR DNA-binding protein 43 (TDP-43) forms the cytoplasmic hallmarks associated with patients suffering from amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitin. Under normal conditions, TDP-43 is a 414-amino acid protein; however, aggregates are enriched with N-terminal truncations which contain residues 267-414, known as the C-terminal domain of TDP-43 (TDP-43). To gain residue-specific information on the aggregation process of TDP-43, we created three single-Trp containing mutants (W385F/W412F, W334F/W412F, and W334F/W385F) by substituting two of the three native Trp residues with Phe, yielding fluorescent probes at W334, W385, and W412, respectively. Read More

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Evolution of Micron-Spaced Patterns within Precipitating Patterns of Synthesized Silver Nanoparticles in a Nanodot-Embedded PVA/PVP Film.

Langmuir 2021 04 8;37(15):4460-4467. Epub 2021 Apr 8.

Department of Basic Sciences & Humanities, Rajiv Gandhi Institute of Petroleum Technology, Jais, Amethi 229304, Uttar Pradesh, India.

Periodic pattern formation beyond conventional precipitation reactions of electrolytes is of greater importance for gaining insights into the driving forces behind spontaneous spatiotemporal pattern formation in living matter. The Liesegang phenomenon is considered to be one of the important models for understanding well-defined periodic patterns. In this study, we have used biomolecule-derived photoluminescent carbon nanodots as reducing agents that were embedded in thin polymer films. Read More

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Controlled aggregation enhances immunomodulatory potential of mesenchymal stromal cell aggregates.

Stem Cells Transl Med 2021 Apr 5. Epub 2021 Apr 5.

Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA.

Human mesenchymal stromal cells (MSCs) are promising candidates for cell therapy due to their ease of isolation and expansion and their ability to secrete antiapoptotic, pro-angiogenic, and immunomodulatory factors. Three-dimensional (3D) aggregation "self-activates" MSCs to augment their pro-angiogenic and immunomodulatory potential, but the microenvironmental features and culture parameters that promote optimal MSC immunomodulatory function in 3D aggregates are poorly understood. Here, we generated MSC aggregates via three distinct methods and compared them with regard to their (a) aggregate structure and (b) immunomodulatory phenotype under resting conditions and in response to inflammatory stimulus. Read More

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Modeling the Inhibition Kinetics of Curcumin, Orange G, and Resveratrol with Amyloid-β Peptide.

ACS Omega 2021 Mar 19;6(12):8680-8686. Epub 2021 Mar 19.

School of Pharmacy, Health Sciences Campus, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.

The β-amyloid (Aβ) protein aggregation into toxic forms is one of the major factors in the Alzheimer's disease (AD) pathology. Screening compound libraries as inhibitors of Aβ-aggregation is a common strategy to discover novel molecules as potential therapeutics in AD. In this regard, thioflavin T (ThT)-based fluorescence spectroscopy is a widely used in vitro method to identify inhibitors of Aβ aggregation. Read More

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The role of clearance mechanisms in the kinetics of pathological protein aggregation involved in neurodegenerative diseases.

J Chem Phys 2021 Mar;154(12):125101

Mathematical Institute, University of Oxford, Oxford, United Kingdom.

The deposition of pathological protein aggregates in the brain plays a central role in cognitive decline and structural damage associated with neurodegenerative diseases. In Alzheimer's disease, the formation of amyloid-β plaques and neurofibrillary tangles of the tau protein is associated with the appearance of symptoms and pathology. Detailed models for the specific mechanisms of aggregate formation, such as nucleation and elongation, exist for aggregation in vitro where the total protein mass is conserved. Read More

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Plasmonic Nanoparticles as Optical Sensing Probes for the Detection of Alzheimer's Disease.

Sensors (Basel) 2021 Mar 16;21(6). Epub 2021 Mar 16.

Departamento de Química Farmacológica y Toxicológica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Dr. Carlos Lorca Tobar 964, Independencia, 8380000 Santiago, Chile.

Alzheimer's disease (AD), considered a common type of dementia, is mainly characterized by a progressive loss of memory and cognitive functions. Although its cause is multifactorial, it has been associated with the accumulation of toxic aggregates of the amyloid-β peptide (Aβ) and neurofibrillary tangles (NFTs) of tau protein. At present, the development of highly sensitive, high cost-effective, and non-invasive diagnostic tools for AD remains a challenge. Read More

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