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1.
Inorg Chem ; 2024 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-39360797

RESUMEN

An organometallic iridium (Ir)-complex-functionalized nanographene catalyst Ir-PyPh-GC was prepared via a two-step strategy involving amide ligand modification and metal Ir coordination. Ir-PyPh-GC showed ultrahigh hydrogenation capability, good recyclability, and selectivity for carbonyl derivatives (ketones, aldehydes, and quinones) at a low temperature (40 °C). The as-prepared Ir-complex-based catalyst is less expensive, making it feasible for industrial application.

2.
Phys Rev Lett ; 133(12): 126701, 2024 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-39373445

RESUMEN

It has long been suspected that magnetism could play a vital role in the phase stability of multicomponent high-entropy alloys. However, the nature of the magnetic order, if any, has remained elusive. Here, by using elastic and inelastic neutron scattering, we demonstrate evidence of antiferromagnetic order below ∼80 K and strong spin fluctuations persisting to room temperature in a single-phase face-centered cubic (fcc) CrMnFeCoNi high-entropy alloy. Despite the chemical complexity, the magnetic structure in CrMnFeCoNi can be described as γ-Mn-like, with the magnetic moments confined in alternating (001) planes and pointing toward the ⟨111⟩ direction. Combined with first-principles calculation results, it is shown that the antiferromagnetic order and spin fluctuations help stabilized the fcc phase in CrMnFeCoNi high-entropy alloy.

3.
Front Neurorobot ; 18: 1456192, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39220586

RESUMEN

Combining item feature information helps extract comprehensive sequential patterns, thereby improving the accuracy of sequential recommendations. However, existing methods usually combine features of each item using a vanilla attention mechanism. We argue that such a combination ignores the interactions between features and does not model integrated feature representations. In this study, we propose a novel Feature Interaction Dual Self-attention network (FIDS) model for sequential recommendation, which utilizes dual self-attention to capture both feature interactions and sequential transition patterns. Specifically, we first model the feature interactions for each item to form meaningful higher-order feature representations using a multi-head attention mechanism. Then, we adopt two independent self-attention networks to capture the transition patterns in both the item sequence and the integrated feature sequence, respectively. Moreover, we stack multiple self-attention blocks and add residual connections at each block for all self-attention networks. Finally, we combine the feature-wise and item-wise sequential patterns into a fully connected layer for the next item recommendation. We conduct experiments on two real-world datasets, and our experimental results show that the proposed FIDS method outperforms state-of-the-art recommendation models.

4.
Polymers (Basel) ; 16(18)2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39339015

RESUMEN

The thermal stability and aging kinetics of polyimides have garnered significant research attention. As a newly developed class of high thermal stability polyimide, the thermal aging characteristics and degradation kinetics of phenylene-capped polyimide prepolymer (PMR350) have not yet been reported. In this article, the thermo-oxidative stability of PMR350 was investigated systematically. The thermal degradation kinetics of PMR350 resin under different atmospheres were also analyzed using the Flynn-Wall-Ozawa method, the Kissinger-Akahira-Sunose method, and the Friedman method. Thermogravimetric analysis (TGA) results revealed that the 5% thermal decomposition temperature (Td5%) of PMR350 in a nitrogen atmosphere was 29 °C higher than that in air, and the maximum thermal degradation rate was 0.0025%/°C, which is only one-seventh of that observed in air. Isothermal oxidative aging results indicated that the weight loss rate of PMR350 and the time-dependence relationship follow a first-order exponential growth function. PMR350 resin thermal decomposition reaction under air atmosphere includes one stage, with a degradation activation energy of approximately 57 kJ/mol. The reaction model g(α) fits the F2 model, and the integral form is given by g(α) = 1/(1 - α). In contrast, the thermal decomposition reaction under a nitrogen atmosphere consists of two stages, with degradation activation energies of 240 kJ/mol and 200 kJ/mol, respectively. The reaction models g(α) correspond to the A2 and D3 models, with the integral forms represented as g(α) = [-ln(1 - α)]2 and g(α) = [1 - (1 - α)1/3]2 due to the oxygen accelerating thermal degradation from multiple perspectives. Moreover, PMR350 resin maintained high hardness and modulus even after thermal aging at 350 °C for 300 h. The results indicate that the resin exhibits excellent resistance to thermal and oxygen aging. This study represents the first systematic analysis of the thermal stability characteristics of PMR350 resin, offering essential theoretical insights and data support for understanding the mechanisms of thermal stability modification in PMR350 and its engineering applications.

5.
Crit Rev Oncol Hematol ; 204: 104497, 2024 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-39245296

RESUMEN

Colorectal cancer (CRC) with BRAF V600E mutation presents a formidable scientific and clinical challenge due to its aggressive nature and poor response to standard therapeutic approaches. BRAF V600E mutation-induced conspicuous activation of the MAPK pathway contributes to the relentless tumor progression. Nevertheless, the efficacy of multi-targeted MAPK pathway inhibition remains suboptimal in clinical practice. Patients with high microsatellite instability (MSI-H) have shown favorable results with immune checkpoint inhibitors (ICIs). The combination of the MAPK pathway inhibition with ICIs has recently emerged as a promising regimen to improve clinical outcomes in the microsatellite stable (MSS) subgroup of BRAF V600E-mutant metastatic CRC patients. In this review, we elucidate the unique tumor biology of BRAF V600E-mutant CRC, with a particular focus on the immune features underlying the rationale for ICI treatments in the MSI-H and MSS subpopulations, then highlight the trends in clinical trials of the ICI therapy for BRAF V600E-mutant metastatic CRC.

6.
Adv Mater ; 36(41): e2408678, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39221659

RESUMEN

As an age-related disease, intervertebral disc degeneration is closely related to inflammation and aging. Inflammatory cytokines and cellular senescence collectively contribute to the degradation of intervertebral disc. Blocking this synergy reduces disc extracellular matrix damage caused by inflammation and aging. In this study, drug-loaded nanofibers with sequential targeting functions are constructed through intelligent response, hydrophilicity, and in situ self-assembly empowerment of flurbiprofen. The peptide precursor responds to the cleavage of overexpressed MMP-2 in the degenerative intervertebral disc microenvironment (intracellular and extracellular), resulting in the formation of self-assembled nanofibers that enable the on-demand release of flurbiprofen and COX-2 response. In vitro, Comp. 1 (Flurbiprofen-GFFYPLGLAGEEEERGD) reduces the expression of inflammation-related genes and proteins and the polarization of M1 macrophages by competitively inhibiting COX-2 and increases the expression of extracellular matrix proteins COL-2 and aggrecan. Additionally, it can reduce the expression of Senescence-Associated Secretory Phenotype and DNA damage in aged nucleus pulposus cells and promote the recovery of proliferation and cell cycle. In vivo, drug-loaded nanofibers delay intervertebral disc degeneration by inhibiting inflammation and preventing the accumulation of senescent cells. Therefore, the sequentially targeted self-assembled drug-loaded nanofibers can delay intervertebral disc degeneration by blocking the synergistic effect of inflammatory cytokines and cellular senescence.


Asunto(s)
Degeneración del Disco Intervertebral , Nanofibras , Nanofibras/química , Degeneración del Disco Intervertebral/tratamiento farmacológico , Degeneración del Disco Intervertebral/metabolismo , Degeneración del Disco Intervertebral/patología , Animales , Ciclooxigenasa 2/metabolismo , Metaloproteinasa 2 de la Matriz/metabolismo , Senescencia Celular/efectos de los fármacos , Núcleo Pulposo/metabolismo , Núcleo Pulposo/efectos de los fármacos , Núcleo Pulposo/patología , Humanos , Ratones , Proliferación Celular/efectos de los fármacos
7.
ACS Nano ; 18(37): 25826-25840, 2024 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-39196858

RESUMEN

Engineering nanovaccines capable of targeting dendritic cells (DCs) is desperately required to maximize antigen cross-presentation to effector immune cells, elicit strong immune responses, and avoid adverse reactions. Here, we showed that glucose transporter 1 (Glut-1) on DCs is a reliable target for delivering antigens to DCs, and thus, a versatile antigen delivery strategy using glucosylated nanovaccines was developed for DC-targeted antigen delivery and tumor immunotherapy. The developed glucosylated ovalbumin-loaded nanovaccines highly accumulated in lymph nodes and efficiently engaged with Glut-1 on DCs to accelerate intracellular antigen delivery and promote DC maturation and antigen presentation, which elicited potent antitumor immunity to prevent and inhibit ovalbumin-expressing melanoma. Moreover, immunotherapeutic experiments in DC- and macrophage-depleted animal models confirmed that the glucosylated nanovaccines functioned mainly through DCs. In addition, the neoantigen-delivering glucosylated nanovaccines were further engineered to elicit tumor-specific immune responses against MC38 tumors. This study offers a DC-targeted antigen delivery strategy for cancer immunotherapy.


Asunto(s)
Vacunas contra el Cáncer , Células Dendríticas , Inmunoterapia , Ratones Endogámicos C57BL , Células Dendríticas/inmunología , Células Dendríticas/metabolismo , Animales , Vacunas contra el Cáncer/inmunología , Vacunas contra el Cáncer/química , Vacunas contra el Cáncer/administración & dosificación , Ratones , Ovalbúmina/inmunología , Ovalbúmina/química , Nanopartículas/química , Antígenos de Neoplasias/inmunología , Antígenos de Neoplasias/química , Femenino , Presentación de Antígeno/inmunología , Línea Celular Tumoral , Humanos , Nanovacunas
8.
Int J Pharm ; 664: 124599, 2024 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-39154917

RESUMEN

Local anesthetics (LA), as part of multimodal analgesia, have garnered significant interest for their role in delaying the initiation of opioid therapy, reducing postoperative opioid usage, and mitigating both hospitalization duration and related expenses. Despite numerous endeavors to extend the duration of local anesthetic effects, achieving truly satisfactory long-acting analgesia remains elusive. Drawing upon prior investigations, vesicular phospholipid gels (VPGs) emerge as promising candidates for extended-release modalities in small-molecule drug delivery systems. Therefore, we tried to use the amphiphilicity of phospholipids to co-encapsulate levobupivacaine hydrochloride and meloxicam, two drugs with different hydrophilicity, to obtain a long-term synergistic analgesic effect. Initially, the physicochemical attributes of the formulation were characterized, followed by an examination of its in vitro release kinetics, substantiating the viability of extending the release duration of the dual drugs. Sequentially, in vivo investigations encompassing pharmacokinetic profiling and assessment of analgesic efficacy were undertaken, revealing a prolonged release duration of up to 120 h and attainment of optimal postoperative analgesia. Subsequently, inquiries into the mechanism underlying synergistic analgesic effects and safety evaluations pertinent to the delivery strategy were pursued. In summation, we successfully developed a promising formulation to achieve long-acting analgesia.


Asunto(s)
Anestésicos Locales , Preparaciones de Acción Retardada , Liberación de Fármacos , Levobupivacaína , Meloxicam , Dolor Postoperatorio , Dolor Postoperatorio/tratamiento farmacológico , Anestésicos Locales/administración & dosificación , Anestésicos Locales/farmacocinética , Anestésicos Locales/química , Animales , Meloxicam/administración & dosificación , Meloxicam/farmacocinética , Masculino , Levobupivacaína/administración & dosificación , Fosfolípidos/química , Fosfolípidos/administración & dosificación , Ratas Sprague-Dawley , Bupivacaína/administración & dosificación , Bupivacaína/farmacocinética , Bupivacaína/química , Bupivacaína/análogos & derivados , Analgésicos/administración & dosificación , Analgésicos/química , Analgésicos/farmacocinética , Geles , Sinergismo Farmacológico
9.
ChemSusChem ; : e202401527, 2024 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-39166715

RESUMEN

2,5-Diformylfuran (DFF) is a significant biomass-derived compound with diverse applications in novel furan-based materials, fragrances, fuel additives, and drug synthesis. A pivotal challenge in DFF synthesis is developing a method to produce DFF under mild conditions using sustainable feedstocks. In this study, an affordable 4-hydroxy-2,2,6,6-tetramethylpiperidine (TEMPOL)- assisted Cu(OAc)2 catalytic system for aerobic oxidation reaction of HMF to DFF in liquid sunlight methanol solvent was developed. The effects of parameters such as metal species, catalyst amount, solvent species, ligand structure, and reaction temperature were systematically investigated. The evolution of product distribution in the reaction solution at various times was monitored and analyzed using 1H-NMR spectroscopy. FT-IR and ESI-MS characterizations were employed to integrate experimental findings and elucidate the reaction mechanism. The highest DFF yield of 96% and complete conversion of HMF were obtained. Furthermore, a total DFF yield of 68.6% was achieved from fructose using a two-steps method, demonstrating the potential for scalable production. The establishment of this catalytic system presents a novel approach for the selective preparation of DFF from sustainable feedstocks.

10.
Protein Sci ; 33(9): e5101, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39149996

RESUMEN

Aberrant formation and deposition of human transthyretin (TTR) aggregates causes transthyretin amyloidosis. To initialize aggregation, transthyretin tetramers must first dissociate into monomers that partially unfold to promote entry into the aggregation pathway. The native TTR tetramer (T) is stabilized by docking of the F87 sidechain into an interfacial cavity enclosed by several hydrophobic residues including A120. We have previously shown that an alternative tetramer (T*) with mispacked F87 sidechains is more prone to dissociation and aggregation than the native T state. However, the molecular basis for the reduced stability in T* remains unclear. Here we report characterization of the A120L mutant, where steric hindrance is introduced into the F87 binding site. The x-ray structure of A120L shows that the F87 sidechain is displaced from its docking site across the subunit interface. In A120S, a naturally occurring pathogenic mutant that is less aggregation-prone than A120L, the F87 sidechain is correctly docked, as in the native TTR tetramer. Nevertheless, 19F-NMR aggregation assays show an elevated population of a monomeric aggregation intermediate in A120S relative to a control containing the native A120, due to accelerated tetramer dissociation and slowed monomer tetramerization. The mispacking of the F87 sidechain is associated with enhanced exchange dynamics for interfacial residues. At 298 K, the T* populations of various naturally occurring mutants fall between 4% and 7% (ΔG ~ 1.5-1.9 kcal/mol), consistent with the free energy change expected for undocking and solvent exposure of one of the four F87 sidechains in the tetramer (ΔG ~ 1.6 kcal/mol). Our data provide a molecular-level picture of the likely universal F87 sidechain mispacking in tetrameric TTR that promotes interfacial conformational dynamics and increases aggregation propensity.


Asunto(s)
Prealbúmina , Prealbúmina/química , Prealbúmina/genética , Prealbúmina/metabolismo , Humanos , Modelos Moleculares , Cristalografía por Rayos X , Conformación Proteica , Multimerización de Proteína , Agregado de Proteínas , Neuropatías Amiloides Familiares/genética , Neuropatías Amiloides Familiares/metabolismo , Sitios de Unión , Sustitución de Aminoácidos
11.
RSC Adv ; 14(36): 26115-26122, 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-39161433

RESUMEN

Deuterated potassium dihydrogen phosphate (DKDP) crystals with different deuterium contents have a wide range of applications, such as frequency conversion in high power lasers, electro-optic modulation, and Q-switching crystals for Pockels cells. However, there is a lack of systematic research on the effect of deuterium content on the fundamental structure and properties of these DKDP crystals. To this end, in this study, a series of DKDP crystals with different deuterium contents have been grown using the "point-seed" rapid growth method, and the structure and properties of the crystals have been characterized. The results indicate that as the deuterium content increases, the cell parameter along the a(b)-axis direction gradually increases, and the transmittance gradually increases in the infrared range. A small amount of doping (low H or D ratio) reduces the structural integrity of the crystal, and the crystals at intermediate deuterium concentrations have better crystallinity. The thermal properties of the crystals do no change significantly with the variation in the deuterium content. Overall, these findings can serve as a useful reference for boosting the application of DKDP crystals with various deuterium contents.

12.
Cell Death Dis ; 15(7): 500, 2024 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-39003253

RESUMEN

In recent years, immunotherapy, particularly PD-1 antibodies, have significantly enhanced the outcome of gastric cancer patients. Despite these advances, some patients do not respond well to treatment, highlighting the need to understand resistance mechanisms and develop predictive markers of treatment effectiveness. This study retrospectively analyzed data from 106 patients with stage IV gastric cancer who were treated with first-line immunotherapy in combination with chemotherapy. By comparing plasma cytokine levels between patients resistant and sensitive to PD-1 antibody therapy, the researchers identified elevated IL-4 expression in the resistant patients. Mechanical investigations revealed that IL-4 induces metabolic changes in macrophages that activate the PI3K/AKT/mTOR pathway. This alteration promotes ATP production, enhances glycolysis, increases lactic acid production, and upregulates FcγRIIB expression in macrophages. Ultimately, these changes lead to CD8+ T cell dysfunction and resistance to PD-1 antibody therapy in gastric cancer. These findings highlight the role of IL-4-induced macrophage polarization and metabolic reprogramming in immune resistance and verify IL-4 as potential targets for improving treatment outcomes in gastric cancer patients.


Asunto(s)
Inmunoterapia , Interleucina-4 , Macrófagos , Receptores de IgG , Transducción de Señal , Neoplasias Gástricas , Regulación hacia Arriba , Humanos , Interleucina-4/metabolismo , Macrófagos/metabolismo , Macrófagos/inmunología , Receptores de IgG/metabolismo , Inmunoterapia/métodos , Neoplasias Gástricas/patología , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/inmunología , Neoplasias Gástricas/terapia , Masculino , Resistencia a Antineoplásicos/efectos de los fármacos , Femenino , Receptores de Interleucina-4/metabolismo , Persona de Mediana Edad , Animales , Anciano
13.
Technol Health Care ; 32(4): 2115-2128, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38995811

RESUMEN

BACKGROUND: Colorectal cancer is one of the most common digestive tract tumors. OBJECTIVE: To evaluate the feasibility and safety of laparoscopic colorectal cancer surgery. METHODS: This study retrospectively analyzed early postoperative clinical data of 48 patients with colorectal cancer treated in our hospital between 2015 and 2021, of which 21 underwent laparoscopic colorectal surgery, and 27 underwent laparotomy. There was no significant difference in clinical data. Patients were included if they had colorectal cancer (confirmed by colonoscopy and biopsy pathological examination before surgery), were evaluated for possible radical surgery before surgery, and had no intestinal obstruction, tumor invasion of adjacent organs (by digital rectal examination and preoperative abdominal color Doppler ultrasound, CT confirmed) and no other history of abdominal surgery. Using the method of clinical control study, operation time, intraoperative blood loss, postoperative general condition, surgical lymph node removal (postoperative pathology), surgical complications, gastrointestinal function recovery, surgical before and after blood glucose, body temperature, white blood cells, pain visual analog scale (VAS) and other conditions were compared and analyzed to determine feasibility and safety of laparoscopic surgery for colorectal cancer. RESULTS: Colorectal cancer was successfully removed by laparoscopic radical resection without any significant problems or surgical fatalities. Age, gender, tumor location, stage, and duration of surgery did not differ between laparoscopic and laparotomy operations. Compared to laparotomy, postoperative eating, bowel movements, and blood sugar levels improved. Variations in the length of surgically removed specimens after VAS measurements revealed open and laparoscopic operations. The overall lymph node count was 10.8 ± 1.6, with no variation between the two techniques. CONCLUSION: Laparoscopic colorectal cancer radical surgery is safe and feasible. Also, it has the advantages of minimally invasive surgery. Laparoscopic colorectal cancer radical surgery can comply with the principles of oncology revolutionary.


Asunto(s)
Colonoscopía , Neoplasias Colorrectales , Laparoscopía , Humanos , Laparoscopía/métodos , Femenino , Masculino , Neoplasias Colorrectales/cirugía , Neoplasias Colorrectales/patología , Persona de Mediana Edad , Estudios Retrospectivos , Colonoscopía/métodos , Anciano , Adulto , Tempo Operativo , Estudios de Factibilidad , Complicaciones Posoperatorias/epidemiología
14.
J Pharm Sci ; 113(9): 2851-2860, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39033977

RESUMEN

Rheumatoid arthritis (RA) is a chronic inflammatory joint condition characterized by symmetric, erosive synovitis leading to cartilage erosion and significant disability. Macrophages, pivotal in disease progression, release pro-inflammatory factors upon activation. We developed a nanoparticle delivery system (DXP-PSA NPs), based on palmitic acid modified human serum albumin (PSA), to deliver dexamethasone palmitate (DXP) directly to sites of inflammation, enhancing treatment effectiveness and minimizing possible side effects. The system actively targets scavenger receptor-A on activated macrophages, achieving selective accumulation at inflamed joints. In vitro effect and preliminary targeting abilities were investigated on LPS-activated RAW264.7 cells. The in vivo efficacy and safety were evaluated and compared side to side with commercially available lipid emulsion Limethason® in an advanced adjuvant-induced arthritis rat model. DXP-PSA NPs offer a novel approach to RA treatment and presents promising prospects for clinical translation.


Asunto(s)
Artritis Experimental , Artritis Reumatoide , Dexametasona , Nanopartículas , Ácido Palmítico , Dexametasona/administración & dosificación , Dexametasona/química , Animales , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/metabolismo , Ácido Palmítico/química , Ratones , Células RAW 264.7 , Humanos , Nanopartículas/química , Ratas , Artritis Experimental/tratamiento farmacológico , Antiinflamatorios/administración & dosificación , Antiinflamatorios/farmacología , Antiinflamatorios/química , Antiinflamatorios/farmacocinética , Masculino , Albúmina Sérica Humana/química , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo
15.
Front Neurorobot ; 18: 1428785, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38947247

RESUMEN

Next Point-of-Interest (POI) recommendation aims to predict the next POI for users from their historical activities. Existing methods typically rely on location-level POI check-in trajectories to explore user sequential transition patterns, which suffer from the severe check-in data sparsity issue. However, taking into account region-level and category-level POI sequences can help address this issue. Moreover, collaborative information between different granularities of POI sequences is not well utilized, which can facilitate mutual enhancement and benefit to augment user preference learning. To address these challenges, we propose multi-granularity contrastive learning (MGCL) for next POI recommendation, which utilizes multi-granularity representation and contrastive learning to improve the next POI recommendation performance. Specifically, location-level POI graph, category-level, and region-level sequences are first constructed. Then, we use graph convolutional networks on POI graph to extract cross-user sequential transition patterns. Furthermore, self-attention networks are used to learn individual user sequential transition patterns for each granularity level. To capture the collaborative signals between multi-granularity, we apply the contrastive learning approach. Finally, we jointly train the recommendation and contrastive learning tasks. Extensive experiments demonstrate that MGCL is more effective than state-of-the-art methods.

16.
Adv Sci (Weinh) ; 11(34): e2308279, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38973194

RESUMEN

The coacervation of alpha-synuclein (αSyn) into cytotoxic oligomers and amyloid fibrils are considered pathological hallmarks of Parkinson's disease. While aggregation is central to amyloid diseases, liquid-liquid phase separation (LLPS) and its interplay with aggregation have gained increasing interest. Previous work shows that factors promoting or inhibiting aggregation have similar effects on LLPS. This study provides a detailed scanning of a wide range of parameters, including protein, salt and crowding concentrations at multiple pH values, revealing different salt dependencies of aggregation and LLPS. The influence of salt on aggregation under crowding conditions follows a non-monotonic pattern, showing increased effects at medium salt concentrations. This behavior can be elucidated through a combination of electrostatic screening and salting-out effects on the intramolecular interactions between the N-terminal and C-terminal regions of αSyn. By contrast, this study finds a monotonic salt dependence of LLPS due to intermolecular interactions. Furthermore, it observes time evolution of the two distinct assembly states, with macroscopic fibrillar-like bundles initially forming at medium salt concentration but subsequently converting into droplets after prolonged incubation. The droplet state is therefore capable of inhibiting aggregation or even dissolving aggregates through heterotypic interactions, thus preventing αSyn from its dynamically arrested state.


Asunto(s)
Agregado de Proteínas , alfa-Sinucleína , alfa-Sinucleína/química , alfa-Sinucleína/metabolismo , Sales (Química)/química , Humanos , Enfermedad de Parkinson/metabolismo , Amiloide/metabolismo , Amiloide/química , Concentración de Iones de Hidrógeno , Agregación Patológica de Proteínas/metabolismo , Separación de Fases
17.
Ultrason Sonochem ; 108: 106964, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38943849

RESUMEN

Hydrodynamic cavitation (HC) has emerged as a promising technology for water disinfection. Interestingly, when subjected to specific cavitation pressures, jet pump cavitation reactors (JPCRs) exhibit effective water treatment capabilities. This study investigated the cavitation flow and vorticty transport in a JPCR with various area ratios by utilizing computational fluid dynamics. The results reveal that cavitation is more likely to occur within the JPCR as the area ratio becomes smaller. While as the area ratio decreases, the limit flow ratio also decreases, leading to a reduced operational range for the JPCR. During the cavitation inception stage, only a few bubbles with limited travel distances are generated at the throat inlet. A stable cavitation layer developed between the throat and downstream wall during the limited cavitation stage. In this phase, the primary flow carried the bubbles towards the outlet. In addition, it was found that the vortex stretching, compression expansion, and baroclinic torque terms primarily influence the vorticity transport equation in this context. This work may provide a reference value to the design of JPCRs for water treatment.

18.
ACS Appl Mater Interfaces ; 16(27): 35447-35462, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38940537

RESUMEN

Membranous nephropathy (MN) is a common immune-mediated glomerular disease that requires the development of safe and highly effective therapies. Celastrol (CLT) has shown promise as a therapeutic molecule candidate, but its clinical use is currently limited due to off-target toxicity. Given that excess levels of reactive oxygen species (ROS) contributing to podocyte damage is a key driver of MN progression to end-stage renal disease, we rationally designed ROS-responsive cationic polymeric nanoparticles (PPS-CPNs) with a well-defined particle size and surface charge by employing poly(propylene sulfide)-polyethylene glycol (PPS-PEG) and poly(propylene sulfide)-polyethylenimine (PPS-PEI) to selectively deliver CLT to the damaged glomerulus for MN therapy. Experimental results show that PPS-CPNs successfully crossed the fenestrated endothelium, accumulated in the glomerular basement membrane (GBM), and were internalized by podocytes where rapid drug release was triggered by the overproduction of ROS, thereby outperforming nonresponsive CLT nanotherapy to alleviate subepithelial immune deposits, podocyte foot process effacement, and GBM expansion in a rat MN model. Moreover, the ROS-responsive CLT nanotherapy was associated with significantly lower toxicity to major organs than free CLT. These results suggest that encapsulating CLT into PPS-CPNs can improve efficacy and reduce toxicity as a promising treatment option for MN.


Asunto(s)
Glomerulonefritis Membranosa , Nanopartículas , Triterpenos Pentacíclicos , Podocitos , Especies Reactivas de Oxígeno , Animales , Especies Reactivas de Oxígeno/metabolismo , Nanopartículas/química , Glomerulonefritis Membranosa/tratamiento farmacológico , Glomerulonefritis Membranosa/patología , Ratas , Triterpenos Pentacíclicos/química , Triterpenos Pentacíclicos/farmacología , Podocitos/efectos de los fármacos , Podocitos/metabolismo , Polietilenglicoles/química , Glomérulos Renales/efectos de los fármacos , Glomérulos Renales/patología , Glomérulos Renales/metabolismo , Ratas Sprague-Dawley , Humanos , Masculino , Polímeros/química , Polímeros/farmacología , Sulfuros/química , Sulfuros/farmacología , Sulfuros/uso terapéutico , Polietileneimina/química , Portadores de Fármacos/química
19.
Food Chem ; 456: 139866, 2024 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-38852446

RESUMEN

Effective crosslinking among food constituents has the potential to enhance their overall quality. Distarch phosphate (DSP), a common food additive employed as a thickening agent, bears a pre-crosslinked oligosaccharide (PCO) moiety within its molecular structure. Once this moiety is released, its double reducing end has the potential to undergo crosslinking with amino-rich macromolecules through Maillard reaction. In this study, hydrolyzed distarch phosphate (HDSP) was synthesized, and spectroscopic analysis verified the presence of PCO within HDSP. Preliminary validation experiment showed that HDSP could crosslink chitosan to form a hydrogel and significant browning was also observed during the process. Furthermore, rehydrated sea cucumber (RSC) crosslinked with HDSP exhibited a more intact appearance, higher mechanical strength, better color profile, and increased water-holding capacity. This series of results have confirmed that HDSP is capable to crosslink amino-rich macromolecules and form more stable three-dimensional network.


Asunto(s)
Fosfatos , Pepinos de Mar , Animales , Pepinos de Mar/química , Hidrólisis , Fosfatos/química , Aditivos Alimentarios/química , Reactivos de Enlaces Cruzados/química , Reacción de Maillard , Oligosacáridos/química
20.
J Mol Biol ; 436(16): 168673, 2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-38909653

RESUMEN

The aggregation pathway of transthyretin (TTR) proceeds through rate-limiting dissociation of the tetramer (a dimer of dimers) and partial misfolding of the resulting monomer, which assembles into amyloid structures through a downhill polymerization mechanism. The structural features of the aggregation-prone monomeric intermediate are poorly understood. NMR relaxation dispersion offers a unique opportunity to characterize amyloidogenic intermediates when they exchange on favorable timescales with NMR-visible ground states. Here we use NMR to characterize the structure and conformational dynamics of the monomeric F87E mutant of human TTR. Chemical shifts derived from analysis of multinuclear relaxation dispersion data provide insights into the structure of a low-lying excited state that exchanges with the ground state of the F87E monomer at a rate of 3800 s-1. Disruption of the subunit interfaces of the TTR tetramer leads to destabilization of edge strands in both ß-sheets of the F87E monomer. Conformational fluctuations are propagated through the entire hydrogen bonding network of the DAGH ß-sheet, from the inner ß-strand H, which forms the strong dimer-dimer interface in the TTR tetramer, to outer strand D which is unfolded in TTR fibrils. Fluctuations are also propagated from the AB loop in the weak dimer-dimer interface to the EF helix, which undergoes structural remodeling in fibrils. The conformational fluctuations in both regions are enhanced at acidic pH where amyloid formation is most favorable. The relaxation dispersion data provide insights into the conformational dynamics of the amyloidogenic state of monomeric TTR that predispose it for structural remodeling and progression to amyloid fibrils.


Asunto(s)
Amiloide , Prealbúmina , Conformación Proteica , Prealbúmina/química , Prealbúmina/metabolismo , Prealbúmina/genética , Humanos , Amiloide/química , Amiloide/metabolismo , Multimerización de Proteína , Modelos Moleculares , Enlace de Hidrógeno , Mutación , Resonancia Magnética Nuclear Biomolecular
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