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1.
Mol Cell Proteomics ; 23(6): 100784, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38735538

RESUMEN

Colorectal cancer (CRC) is characterized by high morbidity, high mortality, and limited response to immunotherapies. The peripheral immune system is an important component of tumor immunity, and enhancements of peripheral immunity help to suppress tumor progression. However, the functional alterations of the peripheral immune system in CRC are unclear. Here, we used mass spectrometry-based quantitative proteomics to establish a protein expression atlas for the peripheral immune system in CRC, including plasma and five types of immune cells (CD4+ T cells, CD8+ T cells, monocytes, natural killer cells, and B cells). Synthesizing the results of the multidimensional analysis, we observed an enhanced inflammatory phenotype in CRC, including elevated expression of plasma inflammatory proteins, activation of the inflammatory pathway in monocytes, and increased inflammation-related ligand-receptor interactions. Notably, we observed tumor effects on peripheral T cells, including altered cell subpopulation ratios and suppression of cell function. Suppression of CD4+ T cell function is mainly mediated by high expression levels of protein tyrosine phosphatases. Among them, the expression of protein tyrosine phosphatase receptor type J (PTPRJ) gradually increased with CRC progression; knockdown of PTPRJ in vitro could promote T cell activation, thereby enhancing peripheral immunity. We also found that the combination of leucine-rich α-2 glycoprotein 1 (LRG1) and apolipoprotein A4 (APOA4) had the best predictive ability for colorectal cancer and has the potential to be a biomarker. Overall, this study provides a comprehensive understanding of the peripheral immune system in CRC. It also offers insights regarding the potential clinical utilities of these peripheral immune characteristics as diagnostic indicators and therapeutic targets.


Asunto(s)
Neoplasias Colorrectales , Proteómica , Humanos , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/inmunología , Neoplasias Colorrectales/patología , Proteómica/métodos , Masculino , Femenino , Sistema Inmunológico/metabolismo , Persona de Mediana Edad , Anciano , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Linfocitos T CD8-positivos/inmunología
2.
Int J Mol Sci ; 25(7)2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38612472

RESUMEN

Birinapant, an antagonist of the inhibitor of apoptosis proteins, upregulates MHCs in tumor cells and displays a better tumoricidal effect when used in combination with immune checkpoint inhibitors, indicating that Birinapant may affect the antigen presentation pathway; however, the mechanism remains elusive. Based on high-resolution mass spectrometry and in vitro and in vivo models, we adopted integrated genomics, proteomics, and immunopeptidomics strategies to study the mechanism underlying the regulation of tumor immunity by Birinapant from the perspective of antigen presentation. Firstly, in HT29 and MCF7 cells, Birinapant increased the number and abundance of immunopeptides and source proteins. Secondly, a greater number of cancer/testis antigen peptides with increased abundance and more neoantigens were identified following Birinapant treatment. Moreover, we demonstrate the existence and immunogenicity of a neoantigen derived from insertion/deletion mutation. Thirdly, in HT29 cell-derived xenograft models, Birinapant administration also reshaped the immunopeptidome, and the tumor exhibited better immunogenicity. These data suggest that Birinapant can reshape the tumor immunopeptidome with respect to quality and quantity, which improves the presentation of CTA peptides and neoantigens, thus enhancing the immunogenicity of tumor cells. Such changes may be vital to the effectiveness of combination therapy, which can be further transferred to the clinic or aid in the development of new immunotherapeutic strategies to improve the anti-tumor immune response.


Asunto(s)
Presentación de Antígeno , Dipéptidos , Indoles , Masculino , Animales , Humanos , Terapia Combinada , Modelos Animales de Enfermedad
3.
World J Surg Oncol ; 21(1): 128, 2023 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-37032354

RESUMEN

INTRODUCTION: Radial forearm flap (RFF) is widely used in oral reconstruction. However, the donor-site defect remains the main limit. In this paper, V-shaped kiss RFF (VRFF) is described as a novel technique to improve aesthetics and function of it. A retrospective study was conducted to introduce VRFF and evaluate its effect and safety. METHODS: A total of 21 patients who underwent VRFF for oral reconstruction, and 23 patients who underwent conventional RFF from February 2016 to April 2018 were included in this study. Direct comparisons were made on patient's subjective evaluation of postoperative hand function and degree of scarring and objective donor-site function assessment including range of wrist movements and grip strength before and after surgery between the two groups. RESULTS: No skin grafts were used in the VRFF group, and 20 of 21 patients achieved primary healing at donor site, while all patients from the RFF group had skin grafts. And 18 of 23 patients achieved primary healing. The postoperative scar score of donor site in the VRFF group was significantly higher than that in the RFF group (3.4 vs 2.8, P = 0.035). There were no significant differences in other subjective evaluation and donor-site morbidity and hand function assessment. CONCLUSION: VRFF is able to provide a new and simple method to close donor-site defect and realize a better healing in donor site.


Asunto(s)
Colgajos Tisulares Libres , Procedimientos de Cirugía Plástica , Humanos , Estudios Retrospectivos , Trasplante de Piel/métodos , Antebrazo/cirugía , Cicatriz/etiología , Cicatriz/prevención & control
4.
Ecotoxicol Environ Saf ; 262: 115311, 2023 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-37531926

RESUMEN

A complete understanding of the associations of ambient air pollution with prevalence of pulmonary nodule is lacking. We aimed to investigate the associations of ambient air pollutants with prevalence of pulmonary nodule. A total of 9991 health examination participants was enrolled and 3166 was elected in the final in Shijiazhuang between April 1st, 2018, and December 31st, 2018. 107 participants were diagnosed in pulmonary nodule while 3059 participants were diagnosed in non-pulmonary (named control). The individual exposure of participants was evaluation by Empirical Bayesian Kriging model according to their residential or work addresses. The pulmonary nodules were found and diagnosed by health examination through chest x-ray detection. Our results suggested that there were positive associations between prevalence of pulmonary nodules and PM2.5 (OR = 1.06, 95% CI: 1.02, 1.11) as well as O3 (OR = 1.49, 95% CI: 1.35, 1.66) levels. The platelet count (PLT) acted as the mediator of pulmonary nodules related with the PM2.5 exposure, while the neutrophil-to-lymphocyte ratio (NLR) as well as platelet-to-lymphocyte ratio (PLR) were the mediators of pulmonary nodules related with the O3 exposure. This study suggests that long-term exposure to PM2.5 and O3 may significantly associated with prevalence of pulmonary nodules, and the above associations are mediated by PLT, NLR and PLR.

5.
Int J Mol Sci ; 24(21)2023 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-37958984

RESUMEN

Metastasis leads to a high mortality rate in colorectal cancer (CRC). Increased neutrophil extracellular traps (NETs) formation is one of the main causes of metastasis. However, the mechanism of NETs-mediated metastasis remains unclear and effective treatments are lacking. In this study, we found neutrophils from CRC patients have enhanced NETs formation capacity and increased NETs positively correlate with CRC progression. By quantitative proteomic analysis of clinical samples and cell lines, we found that decreased secreted protein acidic and rich in cysteine (SPARC) results in massive NETs formation and integrin α5ß1 is the hub protein of NETs-tumor cell interaction. Mechanistically, SPARC regulates the activation of the nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) pathway by interacting with the receptor for activated C kinase 1 (RACK1). Over-activated NADPH oxidase generates more reactive oxygen species (ROS), leading to the release of NETs. Then, NETs upregulate the expression of integrin α5ß1 in tumor cells, which enhances adhesion and activates the downstream signaling pathways to promote proliferation and migration. The combination of NADPH oxidase inhibitor diphenyleneiodonium chloride (DPI) and integrin α5ß1 inhibitor ATN-161 (Ac-PHSCN-NH2) effectively suppresses tumor progression in vivo. Our work reveals the mechanistic link between NETs and tumor progression and suggests a combination therapy against NETs-mediated metastasis for CRC.


Asunto(s)
Neoplasias Colorrectales , Trampas Extracelulares , Humanos , Trampas Extracelulares/metabolismo , NADPH Oxidasas/metabolismo , Integrina alfa5beta1/metabolismo , Osteonectina/metabolismo , Proteómica , Neutrófilos/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Neoplasias Colorrectales/patología
6.
Analyst ; 147(22): 4980-4985, 2022 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-36197295

RESUMEN

DNA methyltransferase (MTase) is an important regulatory enzyme in various biological processes. However, current methods for investigating MTase activity are still limited in terms of sensitivity and/or generality. Herein, we proposed a dual amplification fluorescence strategy for the ultrasensitive detection of DNA adenine methylation methyltransferase (Dam MTase) activity based on strand displacement amplification (SDA) coupled with rolling circle amplification (RCA). In this study, the hairpin probe could not be cleaved by Nt.AlwI nicking endonuclease (Nt.AlwI) in the presence of Dam MTase, and the subsequent SDA-RCA reaction was blocked, resulting in a weak fluorescence signal. Moreover, the blocking effect was more pronounced at a higher concentration of Dam MTase. This assay provides a very low detection limit (down to 0.0067 U ml-1), as well as good selectivity against other types of MTases (e.g., CpG methyltransferase (M.SssI MTase)). In addition, the analytical mode improves the generality and can be extended to the detection of other types of DNA MTases.


Asunto(s)
Técnicas Biosensibles , Metilasas de Modificación del ADN , Metilación de ADN , Espectrometría de Fluorescencia/métodos , Metiltransferasas/genética , ADN/genética , Técnicas Biosensibles/métodos
7.
J Physiol ; 599(11): 2887-2906, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33873245

RESUMEN

KEY POINTS: A decrease in protein synthesis plays a major role in the loss of muscle mass that occurs in response to immobilization. In mice, immobilization leads to a rapid (within 6 h) and progressive decrease in the rate of protein synthesis and this effect is mediated by a decrease in translational efficiency. Deep proteomic and phosphoproteomic analyses of mouse skeletal muscles revealed that the rapid immobilization-induced decrease in protein synthesis cannot be explained by changes in the abundance or phosphorylation state of proteins that have been implicated in the regulation of translation. ABSTRACT: The disuse of skeletal muscle, such as that which occurs during immobilization, can lead to the rapid loss of muscle mass, and a decrease in the rate of protein synthesis plays a major role in this process. Indeed, current dogma contends that the decrease in protein synthesis is mediated by changes in the activity of protein kinases (e.g. mTOR); however, the validity of this model has not been established. Therefore, to address this, we first subjected mice to 6, 24 or 72 h of unilateral immobilization and then used the SUnSET technique to measure changes in the relative rate of protein synthesis. The result of our initial experiments revealed that immobilization leads to a rapid (within 6 h) and progressive decrease in the rate of protein synthesis and that this effect is mediated by a decrease in translational efficiency. We then performed a deep mass spectrometry-based analysis to determine whether this effect could be explained by changes in the expression and/or phosphorylation state of proteins that regulate translation. From this analysis, we were able to quantify 4320 proteins and 15,020 unique phosphorylation sites, and surprisingly, the outcomes revealed that the rapid immobilization-induced decrease in protein synthesis could not be explained by changes in either the abundance, or phosphorylation state, of proteins. The results of our work not only challenge the current dogma in the field, but also provide an expansive resource of information for future studies that are aimed at defining how disuse leads to loss of muscle mass.


Asunto(s)
Atrofia Muscular , Proteómica , Animales , Inmovilización , Ratones , Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Fosforilación
8.
Analyst ; 145(24): 7893-7897, 2021 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-33016298

RESUMEN

MicroRNAs (miRNAs) have played a vital role in the regulation of gene expression and have been considered as potential biomarker candidates for early cancer diagnosis. Rapid and sensitive detection of microRNAs is highly desired. Here, we present a new method to rapidly and sensitively determine microRNAs based on the technology of gold nanoparticle catalyzed silver staining enhancement. The new method involves the sandwich hybridization of a capture probe immobilized on a magnetic bead, a reporter probe assembled on gold nanoparticles and a miRNA target, catalytic silver precipitation by gold nanoparticles, magnetic collection of the enhanced sandwich complex, dissolution of the silver precipitation and stripping detection. Using the proposed method the microRNA-7a assay was successfully carried out in less than 70 min and the detection limit was as low as 15 fM. The proposed biosensor may hold great promise in biological monitoring of microRNAs.


Asunto(s)
Técnicas Biosensibles , Nanopartículas del Metal , MicroARNs , Catálisis , Oro , Límite de Detección , MicroARNs/genética , Plata
9.
Sex Health ; 18(1): 119-121, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33588985

RESUMEN

This study shows that there is a huge gap between young females' willingness and practice of accepting voluntary counselling and testing (VCT). Only 2.16% (894/41336) of the participants have had HIV/AIDS tests. The study identified age, education major, confidentiality, attitude, accuracy, self-assessment and expense as major factors associated with young female people's acceptance of VCT in China. Therefore, in order to promote HIV VCT among young females, it is necessary for future programs to be sensitive to the targeted population's needs.


Asunto(s)
Infecciones por VIH , Universidades , China/epidemiología , Consejo , Estudios Transversales , Femenino , Infecciones por VIH/diagnóstico , Infecciones por VIH/epidemiología , Conocimientos, Actitudes y Práctica en Salud , Humanos , Aceptación de la Atención de Salud , Estudiantes
10.
J Surg Oncol ; 118(8): 1326-1334, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30332510

RESUMEN

BACKGROUND AND OBJECTIVES: Long noncoding RNAs (lncRNAs) play key roles in carcinoma metastasis. We aimed to investigate lncRNA LINC01133 in oral squamous cell carcinoma (OSCC) metastasis. METHODS: The RNA levels of LINC01133 and growth and differentiation factor 15 (GDF15) in tissue samples from OSCC patients, and OSCC cell lines were tested by real-time quantitative polymerase chain reaction (RT-qPCR). SPSS20.0 was used to perform statistical analysis of LINC01133 expression in clinical samples and correlate expression of LINC01133 and GDF15. Cell migration/invasion was assessed via transwell assays. Downstream genes of LINC01133 were screened using RNA-seq and validated by RT-qPCR. GDF15 protein levels were evaluated via Western blot analysis. RESULTS: LINC01133 was downregulated in OSCCs; higher expression of LINC01133 in OSCCs was correlated with less metastasis and better prognosis. LINC01133 inhibited OSCC cell migration and invasion. RNA-seq data showed that LINC01133 inhibited GDF15, and GDF15 could rescue inhibition of OSCC cell migration and invasion caused by LINC01133. Interestingly, GDF15 also inhibited LINC01133. Furthermore, a significant negative correlation between expression of LINC01133 and GDF15 was validated in the clinical study. CONCLUSIONS: Collectively, these data indicate that LINC01133 inhibited OSCC metastasis via a feedback regulation loop of reciprocal inhibition with GDF15, suggesting a new diagnostic and therapeutic target for OSCC.


Asunto(s)
Factor 15 de Diferenciación de Crecimiento/antagonistas & inhibidores , Neoplasias de la Boca/genética , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Procesos de Crecimiento Celular/fisiología , Línea Celular , Línea Celular Tumoral , Movimiento Celular , Retroalimentación Fisiológica , Factor 15 de Diferenciación de Crecimiento/genética , Factor 15 de Diferenciación de Crecimiento/metabolismo , Humanos , Neoplasias de la Boca/metabolismo , Neoplasias de la Boca/patología , Metástasis de la Neoplasia , ARN Largo no Codificante/biosíntesis , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/patología , Transcriptoma
11.
Skinmed ; 15(3): 227-229, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28705290

RESUMEN

A 45-year-old Chinese man had begun to show asymmetry of the face 30 years previously. Subsequently, he developed visual extinction of the right eye, slight numbness, and weakness of the left extremities. Simultaneously, multiple atrophic brownish patches occurred on his side. He denied prior trauma or tick bites at those sites. There was no report of preceding redness, induration, or a history of trauma. The atrophic lesions extended and enlarged slowly. Ten years previously, some brownish patches with normal texture had appeared on the right side of the trunk. There was no further progression of the lesions. In November 2010, the patient consulted our department for the final diagnosis and prognosis of his disease. He did not suffer from epileptic seizures and had no history of a tick bite or Lyme disease.


Asunto(s)
Asimetría Facial/complicaciones , Dermatosis Facial/patología , Hiperpigmentación/patología , Piel/patología , Lengua/patología , Atrofia/complicaciones , Atrofia/diagnóstico , Dorso , Extremidades , Dermatosis Facial/complicaciones , Dermatosis Facial/diagnóstico , Humanos , Hiperpigmentación/complicaciones , Masculino , Persona de Mediana Edad , Trastornos de la Visión/complicaciones
12.
Anal Chem ; 87(5): 2945-51, 2015 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-25635709

RESUMEN

Genomic 5-methylcytosine (5-mC) modification is known to extensively regulate gene expression. The sensitive and convenient analysis of gene-specific methylation is wishful but challenging due to the lack of means that can sensitively and sequence-selectively discriminate 5-mC from cytosine without the need for polymerase chain reaction. Here we report a chemical-oxidation cleavage triggered exponential amplification reaction (EXPAR) method named COEXPAR for gene-specific methylation analysis. EXPAR was proved to not only have rapid amplification kinetics under isothermal condition but also show excellent sequence-selectivity and linear-dependence on EXPAR trigger. Further initiation of EXPAR by chemical-cleavage of DNA at 5-mC, the COEXPAR showed high specificity for methylated and nonmethylated DNA, and ∼10(7) copies of triggers were replicated in 20 min, which were used to quantify the methylation level at the methylation loci. As a result, the gene-specific methylation level of a p53 gene fragment, as a target model, was analyzed in two linear ranges of 10 fM-1 pM and 1 pM-10 nM, and limits of detection of 411 aM (S/N = 3) by fluorescence, and 576 aM (S/N = 3) by electrochemistry. The method fulfilled the assay in an isothermal way in ∼5 h without the need for tedious sample preparation and accurate thermocycling equipment, which is likely to be a facile and ultrasensitive way for gene-specific methylation analysis.


Asunto(s)
División del ADN , Metilación de ADN , ADN/análisis , Electroquímica , Técnicas de Amplificación de Ácido Nucleico/métodos , Compuestos Orgánicos/química , Secuencia de Bases , Fluorescencia , Humanos , Cinética , Límite de Detección , Espectrometría de Masas , Datos de Secuencia Molecular , Oxidación-Reducción
13.
Int J Mol Sci ; 15(2): 3336-55, 2014 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-24566153

RESUMEN

Ceramides are second messengers involved in several intracellular processes in cancer cells, amongst others. The aim of this study was to evaluate the anti-tumor efficacy of C2-ceramide (C2-Cer; N-acetyl-D-sphingosine) by investigating cell death and autophagy in head and neck squamous cell carcinoma (HNSCC) cells. C2-Cer showed concentration-dependent cytotoxicity in HN4 and HN30 cell lines. It simultaneously induced caspase-3-independent apoptosis and programmed necrosis. C2-Cer markedly increased the expression level of microtubule-associated protein 1 light chain 3B (LC3B) type II associated with protective autophagy. An autophagy inhibitor enhanced C2-Cer-mediated cytotoxicity, while a programmed-necrosis inhibitor produced the opposite effect. Furthermore, C2-Cer up-regulated the phosphorylation of extracellular signal-regulated kinase 1/2, but down-regulated its downstream substrate phospho-mammalian target of rapamycin (p-mTOR) during the autophagy process. These results suggested that C2-Cer exerts anti-tumor effects by inducing programmed apoptosis and necrosis in HNSCC, and these cytotoxic effects are enhanced by an autophagy inhibitor.


Asunto(s)
Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Esfingosina/análogos & derivados , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Caspasa 3/metabolismo , Línea Celular Tumoral , Fragmentación del ADN/efectos de los fármacos , Neoplasias de Cabeza y Cuello/metabolismo , Neoplasias de Cabeza y Cuello/patología , Humanos , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Necrosis , Fosforilación/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Esfingosina/toxicidad , Serina-Treonina Quinasas TOR/metabolismo
14.
Skinmed ; 12(6): 385-7, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25823087

RESUMEN

A 22-year-old woman was referred to our hospital for pigmented lesions located on her face. These had gradually increased during the past 4 years. Computed tomography (CT) of her head revealed no significant parenchymal abnormalities of temporal, maxillary and sphenoid bones or of either parietal bone. Further screening, including neurologic, ophthalmologic, orthopedic, and visceral investigations, did not reveal any abnormalities. There was no family history of abnormal cutaneous pigmentation.


Asunto(s)
Nevo de Ota/patología , Neoplasias Cutáneas/patología , Cara , Femenino , Humanos , Nevo de Ota/diagnóstico , Neoplasias Cutáneas/diagnóstico , Tomografía Computarizada por Rayos X , Adulto Joven
15.
Anal Sci ; 40(2): 285-290, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38062249

RESUMEN

The rapid and accurate detection of miRNAs is of great significance for early diagnosis and treatment of cancer. Hence, a novel enzyme-free and label-free electrochemical biosensor based on bio-barcode amplification for detecting miRNAs was presented. Sandwich structures constructed of magnetic nanoparticles modified with DNA probes, gold nanoparticles with numerous barcoded DNA strands that hybridized with target miRNAs were fabricated as the amplifier. The released barcoded DNA strands then acted as the secondary targets and triggered the electrochemical sensor with a significant electrochemical response. A highly sensitive (detection limit of 0.24 fM) and selective electrochemical miRNA detection was realized, which has great potential for application in miRNA-related clinical diagnosis and biochemical research.


Asunto(s)
Técnicas Biosensibles , Nanopartículas del Metal , MicroARNs , MicroARNs/genética , Oro/química , Nanopartículas del Metal/química , ADN/química , Técnicas Electroquímicas , Límite de Detección
16.
Carbohydr Polym ; 330: 121764, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38368079

RESUMEN

The rheological properties of a substance depend greatly on its morphology, and rod-shaped cellulose nanocrystals (RCNCs) and cellulose nanofibrils (CNFs) have been extensively studied for their rheological properties. Nevertheless, the rheological properties of disc-shaped cellulose nanocrystals (DCNCs) with crystalline allomorph II derived from mercerized cellulose remain unknown yet. This work investigated the DCNCs' rheological properties in depth using steady-shear and oscillation measurements. At the same concentration, DCNC's suspension viscosity is lower than that of RCNC; RCNC has an instinct viscosity of 258.2, while DCNC has 187.9. Comparing RCNC suspensions with cellulose nanorods, DCNC has a lower aspect ratio and exhibits a distinct steady shear behavior. Under polarized film, DCNC suspension cannot self-assemble into chiral or liquid crystal phases, and with increasing concentrations, the system transitions from an isotropic phase to a gel phase. Oscillation sweeps demonstrate that the gel transition occurs at 7 %-8 %. Based on thixotropic recovery sweep outcomes, the high-stress oscillations enhance the network structure of DCNC suspensions, which is significantly different from that of RCNC suspensions. Results demonstrate the unique properties of DCNC, highlighting its application as a rheological modifier.

17.
Carbohydr Polym ; 330: 121822, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38368103

RESUMEN

Hydroxypropyl cellulose (HPC) is a sustainable cellulose derivative valued for its excellent biocompatibility and solubility and is widely used in various fields. Recent scientific research on high-substituted HPC mainly focused on its efficient preparation and phase transition behavior. Herein, a novel strategy of high-substituted HPC synthesis was demonstrated by employing DMSO/TBAF·3H2O as a cellulose solvent, exhibiting more efficiency than traditional approaches. High-substituted HPC prepared has remarkable thermal stability, exceptional hydrophilicity, and satisfactory solubility. Phase transition behavior of HPC with varying molar degrees of substitution (MS) was delved and a notable negative correlation between MS and cloud point temperature (TCP), was revealed, particularly evident at an MS of 12.3, where the TCP drops to 33 °C. Moreover, a unique self-assembly behavior featuring structural color and responsiveness to force in a solvent-free environment emerged when the MS exceeded 10.4. These insights comprehensively strengthen the understanding and knowledge of high-substituted HPC, simultaneously paving the way for further HPC investigation and exploitation.

18.
Int J Biol Macromol ; 274(Pt 2): 133504, 2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-38944069

RESUMEN

We study the effect of electrolytes on the stability in aqueous media of spherical lignin particles (LP) and its relevance to Pickering emulsion stabilization. Factors considered included the role of ionic strength on morphology development, LP size distribution, surface charge, interfacial adsorption, colloidal and wetting behaviors. Stable emulsions are formed at salt concentrations as low as 50 mM, with the highest stability observed at a critical concentration (400 mM). We show salt-induced destabilization of LP aqueous dispersions at an ionic strength >400 mM. At this critical concentration LP flocculation takes place and particulate networks are formed. This has a profound consequence on the stability of LP-stabilized Pickering emulsions, affecting rheology and long-term stability. The results along with quartz microgravimetry and confocal microscopy observations suggest a possible mechanism for stabilization that considers the interfacial adsorption of LP at oil/water interfaces. The often-unwanted colloidal LP destabilization in water ensues remarkably stable Pickering emulsions by the effect of network formation.

19.
Int J Biol Macromol ; 258(Pt 2): 128936, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38143058

RESUMEN

The properties of cellulose nanocrystals with allomorph II (CNC-II) vary with the sources and the treatments received. In this work, the influences of hydrolysis time, temperature, and the applied acid concentration on the crystal size of CNC-II were investigated by the surface response experimental design. The results showed that temperature was the most significant factor affecting the crystal size of CNC-II during hydrolysis from mercerized cellulose. Then the morphology and colloidal properties of CNC-II were revealed by dynamic laser scattering (DLS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), etc. XRD results indicated that CNC-II had slightly lower crystallinity (80.89 % vs 82.7 %) and larger crystallite size (5.21 vs. 5.13 nm) than CNC-I. TEM and AFM results showed that the morphology of CNC-II were disc-like and rod-like particles, with an average diameter of 14.6 ± 4.7 nm (TEM) and a thickness of 4- 8 nm (AFM). TG and XPS revealed the reduced thermal stability was due to the introduced sulfate groups in CNC-II during hydrolysis. This investigation has addressed the features of CNC-II derived from mercerized cellulose, and it would be promising in fabricating advanced materials.


Asunto(s)
Celulosa , Nanopartículas , Hidrólisis , Celulosa/química , Nanopartículas/química , Temperatura
20.
Int J Biol Macromol ; 270(Pt 1): 132155, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38729462

RESUMEN

This study focuses on enhancing the strength and water stability of paper straws through a novel approach involving a binary emulsion of lignin-based polyurethane and chitosan. Kraft lignin serves as the raw material for synthesizing a blocked waterborne polyurethane, subsequently combined with carboxylated chitosan to form a stable binary emulsion. The resulting emulsion, exhibiting remarkable stability over at least 6 months, is applied to the base paper. Following emulsion application, the paper undergoes torrefaction at 155 °C. This process deblocks isocyanate groups, enabling their reaction with hydroxyl groups on chitosan and fibers, ultimately forming ester bonds. This reaction significantly improves the mechanical strength and hydrophobicity of paper straws. The composite paper straws demonstrate exceptional mechanical properties, including a tensile strength of 47.21 MPa, Young's modulus of 4.33 GPa, and flexural strength of 32.38 MPa. Notably, its water stability is greatly enhanced, with a wet tensile strength of 40.66 MPa, surpassing commercial paper straws by 8 folds. Furthermore, the composite straw achieves complete biodegradability within 120 days, outperforming conventional paper straws in terms of environmental impact. This innovative solution presents a promising and sustainable alternative to plastic straws, addressing the urgent need for eco-friendly products.


Asunto(s)
Quitosano , Emulsiones , Lignina , Papel , Poliuretanos , Resistencia a la Tracción , Poliuretanos/química , Quitosano/química , Lignina/química , Emulsiones/química , Agua/química , Biodegradación Ambiental , Fenómenos Mecánicos , Interacciones Hidrofóbicas e Hidrofílicas , Módulo de Elasticidad
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