Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 71
Filtrar
1.
Clin Transl Oncol ; 2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-39033255

RESUMEN

OBJECTIVE: To observe the clinical efficacy of Camrelizumab in patients with advanced cervical cancer who presented with resistance to initial therapy. METHODS: We retrieved data from 25 patients with advanced (stage IIA2-IV) cervical cancer who were administered a combination salvage therapy with Camrelizumab due to the poor response to initial chemotherapy. The primary outcome was objective response rate (ORR) and disease control rate (DCR), the secondary endpoints included progression-free survival (PFS) and the occurrence of adverse events. To evaluate its long-term effect on PFS, we included 64 patients diagnosed with stage IIA2-IV during the study period, who were responsive to initial radiotherapy or chemotherapy and received conventional therapy as control. RESULTS: Camrelizumab exhibits a high salvage treatment efficacy, with ORR of 80.0% (20/25) and DCR of 88.0% (22/25) in Camrelizumab salvage group (CS group). The PFS in CS group was significantly longer than that in control group. The median follow-up time were 18.1 and 18.3 months in the CS group and the control group, respectively, and neither achieved median PFS. The adverse event (AEs) rates in the CS and control groups were 52.0% (13/25) and 51.6% (33/64), in which the most common adverse events were myelosuppression, cutaneous capillary endothelial proliferation (CCEP), and elevated liver enzymes, and the grade of AEs was less than grade 3 in all patients. CONCLUSION: Camrelizumab demonstrated promising efficacy and safety as the early salvage treatment for patients with advanced cervical cancer.

2.
Spectrochim Acta A Mol Biomol Spectrosc ; 319: 124542, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-38823241

RESUMEN

Enzyme-induced in-situ fluorescence is crucial for the development of biosensing mechanisms and correlative spectroscopic analysis. Inspired by simple p-aminophenol (AP)-controlled synthesis and the specific catalytic reaction of 4-aminophenyl phosphate (APP) triggered by alkaline phosphatase (ALP), our research proposed a strategy to prepare carbon dots (CDs) as fluorescent signals for ALP detection using AP and 3-aminopropyltrimethoxysilane (APTMS) as the precursors. The further constructed ratiometric fluorescence sensor reduced the detection limit of ALP to 0.075 µU/mL by a significant margin. Considering the need for point-of-care testing (POCT), we chose agarose for the preparation of portable hydrogel sensors so that even untrained personnel can quickly achieve semi-quantitative visual detection of ALP using colorimetric cards. These results demonstrate the practical applicability of ratiometric fluorescence sensing hydrogel pillar arrays, which are important for high-sensitivity, visualization, and portable rapid enzyme activity assays.


Asunto(s)
Fosfatasa Alcalina , Técnicas Biosensibles , Hidrogeles , Espectrometría de Fluorescencia , Fosfatasa Alcalina/metabolismo , Fosfatasa Alcalina/análisis , Técnicas Biosensibles/métodos , Espectrometría de Fluorescencia/métodos , Hidrogeles/química , Límite de Detección , Silanos/química , Puntos Cuánticos/química , Carbono/química , Propilaminas/química , Colorimetría/métodos , Humanos
3.
J Affect Disord ; 361: 59-66, 2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-38815762

RESUMEN

Based on previous theories and studies, fear of negative evaluation (FNE) may be a key predictor of suicidal ideation in adolescents. However, few studies examined the longitudinal relationships between FNE and suicidal ideation. This study aimed to explore the bidirectional longitudinal relationships between FNE and suicidal ideation. Meanwhile, based on the Interpersonal Theory of Suicide, this study would examine the longitudinal mediating role of interpersonal needs factors (thwarted belongingness and perceived burdensomeness) on the relationship between FNE and suicidal ideation. A sample of 515 adolescents (Mage = 12.309, SD = 0.807; 49.3 % girls) completed questionnaires on 4 waves, 6 months apart. The Random Intercept Cross-Lagged Panel Models (RI-CLPMs) were utilized to estimate the associations among study variables. The results showed that: (1) there was a significant bidirectional longitudinal relationship between FNE and suicidal ideation; (2) thwarted belongingness and perceived burdensomeness independently and serially mediated the relationship between FNE and suicidal ideation. This study contributed to understanding the complex relationship between FNE and suicidal ideation, emphasizing the critical roles of thwarted belongingness and perceived burdensomeness. The findings underscore the bidirectional nature of these associations and provide insights into the potential pathways involved in the development of suicidal ideation among adolescents.


Asunto(s)
Miedo , Relaciones Interpersonales , Ideación Suicida , Humanos , Adolescente , Femenino , Masculino , Miedo/psicología , Estudios Longitudinales , China , Encuestas y Cuestionarios , Niño , Conducta del Adolescente/psicología , Pueblos del Este de Asia
4.
Gynecol Oncol ; 187: 212-220, 2024 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-38805876

RESUMEN

OBJECTIVE: The use of bevacizumab has been hampered by safety concerns despite demonstrable progression-free survival (PFS) benefit in subjects with platinum-resistant ovarian cancer, highlighting the need for novel effective and safe antiangiogenic agents. This study aimed to characterize the tolerability, safety, and antitumor activities of escalating doses of anti-VEGF antibody suvemcitug plus chemotherapy in platinum-resistant ovarian cancer patients. METHODS: This open-label, dose-escalation trial enrolled adult patients (≥18 years) with platinum-resistant histologically or cytologically-confirmed epithelial ovarian, fallopian tube and primary peritoneal cancer. Eligible patients received paclitaxel or topotecan plus escalating doses of suvemcitug 0.5, 1, 1.5, or 2 mg/kg once every two weeks. The primary endpoints were safety and tolerability, and antitumor activities of suvemcitug. RESULTS: Twenty-nine subjects received paclitaxel (n = 11) or topotecan (n = 18). No dose-limiting toxicities occurred. The most common adverse events of special interest were proteinuria (41.4%), hypertension (20.7%) and epistaxis (10.3%). No gastrointestinal perforations occurred. Nine subjects (31.0%, 95% CI 15.3-50.8) demonstrated investigators-confirmed objective response, including complete response in 1 and partial response in 8. The median PFS was 5.4 months (95% CI 2.2-7.4). CONCLUSIONS: Suvemcitug demonstrated an acceptable safety profile and promising antitumor activities in platinum-resistant ovarian cancer patients, supporting its further clinical development.

5.
Exp Cell Res ; 439(2): 114100, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38797258

RESUMEN

Widespread metastasis is the primary reason for the high mortality associated with ovarian cancer (OC), and effective targeted therapy for tumor aggressiveness is still insufficient in clinical practice. Therefore, it is urgent to find new targets to improve prognosis of patients. PDE4A is a cyclic nucleotide phosphodiesterase that plays a crucial role in the occurrence and development in various malignancies. Our study firstly reported the function of PDE4A in OC. Expression of PDE4A was validated through bioinformatics analysis, RT-qPCR, Western blot, and immunohistochemistry. Additionally, its impact on cell growth and motility was assessed via in vitro and in vivo experiments. PDE4A was downregulated in OC tissues compared with normal tissues and low PDE4A expression was correlated with poor clinical outcomes in OC patients. The knockdown of PDE4A significantly promoted the proliferation, migration and invasion of OC cells while overexpression of PDE4A resulted in the opposite effect. Furthermore, smaller and fewer tumor metastatic foci were observed in mice bearing PDE4A-overexpressing OVCAR3 cells. Mechanistically, downregulation of PDE4A expression can induce epithelial-mesenchymal transition (EMT) and nuclear translocation of Snail, which suggests that PDE4A plays a pivotal role in suppressing OC progression. Notably, Rolipram, the PDE4 inhibitor, mirrored the effects observed with PDE4A deletion. In summary, the downregulation of PDE4A appears to facilitate OC progression by modulating the Snail/EMT pathway, underscoring the potential of PDE4A as a therapeutic target against ovarian cancer metastasis.


Asunto(s)
Movimiento Celular , Proliferación Celular , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4 , Transición Epitelial-Mesenquimal , Regulación Neoplásica de la Expresión Génica , Neoplasias Ováricas , Factores de Transcripción de la Familia Snail , Humanos , Femenino , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/metabolismo , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/genética , Neoplasias Ováricas/patología , Neoplasias Ováricas/genética , Neoplasias Ováricas/metabolismo , Animales , Proliferación Celular/genética , Factores de Transcripción de la Familia Snail/metabolismo , Factores de Transcripción de la Familia Snail/genética , Ratones , Movimiento Celular/genética , Transición Epitelial-Mesenquimal/genética , Línea Celular Tumoral , Progresión de la Enfermedad , Ratones Desnudos , Ratones Endogámicos BALB C , Núcleo Celular/metabolismo , Pronóstico
6.
Biomater Sci ; 12(9): 2446-2447, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38602355

RESUMEN

Correction for 'Clodronate-nintedanib-loaded exosome-liposome hybridization enhances the liver fibrosis therapy by inhibiting Kupffer cell activity' by Keqin Ji et al., Biomater. Sci., 2022, 10, 702-713, https://doi.org/10.1039/D1BM01663F.

7.
Eur J Neurosci ; 59(12): 3309-3321, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38646841

RESUMEN

14-3-3 proteins are a family of regulatory proteins that are abundantly expressed in the brain and enriched at the synapse. Dysfunctions of these proteins have been linked to neurodevelopmental and neuropsychiatric disorders. Our group has previously shown that functional inhibition of these proteins by a peptide inhibitor, difopein, in the mouse brain causes behavioural alterations and synaptic plasticity impairment in the hippocampus. Recently, we found an increased cFOS expression in difopein-expressing dorsal CA1 pyramidal neurons, indicating enhanced neuronal activity by 14-3-3 inhibition in these cells. In this study, we used slice electrophysiology to determine the effects of 14-3-3 inhibition on the intrinsic excitability of CA1 pyramidal neurons from a transgenic 14-3-3 functional knockout (FKO) mouse line. Our data demonstrate an increase in intrinsic excitability associated with 14-3-3 inhibition, as well as reveal action potential firing pattern shifts after novelty-induced hyperlocomotion in the 14-3-3 FKO mice. These results provide novel information on the role 14-3-3 proteins play in regulating intrinsic and activity-dependent neuronal excitability in the hippocampus.


Asunto(s)
Proteínas 14-3-3 , Potenciales de Acción , Región CA1 Hipocampal , Ratones Noqueados , Células Piramidales , Animales , Proteínas 14-3-3/metabolismo , Proteínas 14-3-3/genética , Células Piramidales/metabolismo , Células Piramidales/fisiología , Células Piramidales/efectos de los fármacos , Región CA1 Hipocampal/metabolismo , Región CA1 Hipocampal/fisiología , Ratones , Potenciales de Acción/fisiología , Potenciales de Acción/efectos de los fármacos , Masculino , Ratones Endogámicos C57BL , Oligopéptidos/farmacología , Proteínas
8.
Artículo en Inglés | MEDLINE | ID: mdl-38529888

RESUMEN

INTRODUCTION: Adolescent suicidal ideation (SI) and non-suicidal self-injury (NSSI) are crucial public health issues, yet their co-developmental trajectories during early adolescence and their associations with predictors and outcomes are unclear. This study aimed to (a) identify heterogeneous co-developmental trajectories of SI and NSSI, (b) explore associations between transdiagnostic predictors and trajectories, and (c) assess suicide attempt risk across trajectories. METHODS: Four hundred fifty-three adolescents (Mage = 12.35 years, 48.3% boys) completed surveys at 6-month intervals across 2 years. At Time 1 (Nov 2020), participants completed surveys encompassing SI, and NSSI, along with family, peer, and individual predictors. Subsequent surveys (Times 2-4) measured SI and NSSI, with suicide attempts queried at Time 4. RESULTS: Parallel process latent class growth models revealed three co-developmental groups (i.e., Stable low NSSI and SI; Moderate-NSSI and high-SI, parallel decreasing; High-NSSI and moderate-SI, parallel increasing). Multivariate logistic regression indicated that group membership was predicted by parental rejection, parental warmth, bullying victimization, depressive and anxiety symptoms, thwarted belongingness, and perceived burdensomeness. Adolescents in the "High-NSSI and moderate-SI, parallel increasing" group reported the highest suicide attempt frequency. CONCLUSION: These findings underscore subgroup distinctions and transdiagnostic predictors in comprehending SI and NSSI progression, emphasizing the necessity of dynamic monitoring and tailored interventions for distinct subgroup characteristics.

9.
Front Bioeng Biotechnol ; 12: 1361966, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38410166

RESUMEN

The mitochondria act as the main producers of reactive oxygen species (ROS) within cells. Elevated levels of ROS can activate the mitochondrial apoptotic pathway, leading to cell apoptosis. In this study, we devised a molecular prodrug named CTT2P, demonstrating notable efficacy in facilitating mitochondrial apoptosis. To develop nanomedicine, we enveloped CTT2P within bovine serum albumin (BSA), resulting in the formulation known as CTT2P@B. The molecular prodrug CTT2P is achieved by covalently conjugating mitochondrial targeting triphenylphosphine (PPh3), photosensitizer TPPOH2, ROS-sensitive thioketal (TK), and chemotherapeutic drug camptothecin (CPT). The prodrug, which is chemically bonded, prevents the escape of drugs while they circulate throughout the body, guaranteeing the coordinated dispersion of both medications inside the organism. Additionally, the concurrent integration of targeted photodynamic therapy and cascade chemotherapy synergistically enhances the therapeutic efficacy of pharmaceutical agents. Experimental results indicated that the covalently attached prodrug significantly mitigated CPT cytotoxicity under dark conditions. In contrast, TPPOH2, CTT2, CTT2P, and CTT2P@B nanoparticles exhibited increasing tumor cell-killing effects and suppressed tumor growth when exposed to light at 660 nm with an intensity of 280 mW cm-2. Consequently, this laser-triggered, mitochondria-targeted, combined photodynamic therapy and chemotherapy nano drug delivery system, adept at efficiently promoting mitochondrial apoptosis, presents a promising and innovative approach to cancer treatment.

10.
RSC Adv ; 14(5): 3122-3134, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38249670

RESUMEN

Bacterial infections from chronic wounds affect about 175 million people each year and are a significant clinical problem. Through the integration of photodynamic therapy (PDT) and chemotherapy, a new photosensitizer consisting of ammonium salt N,N-bis-(2-hydroxyethyl)-N-(6-(4-(10,15,20-trimesitylporphyrin-5-yl) phenoxy) hexane)-N-methanaminium bromide, TMP(+) was successfully synthesized with a total reaction yield of 10%. The novel photosensitizer consists of two parts, a porphyrin photosensitizer part and a quaternary ammonium salt part, to achieve the synergistic effect of photodynamic and chemical antibacterial activity. With the increase of TMP(+) concentration, the diameter of the PCT fiber membranes (POL/COL/TMP(+); POL, polycaprolactone; COL, collagen) gradually increased, which was caused by the charge of the quaternary ammonium salt. At the same time, the antibacterial properties were gradually improved. We finally selected the PCT 0.5% group for the antibacterial experiment, with excellent performance in fiber uniformity, hydrophobicity and biosafety. The antibacterial experiment showed that the modified porphyrin TMP(+) had a better antibacterial effect than others. In vivo chronic wound healing experiments proved that the antibacterial and anti-inflammatory effect of the PCTL group was the best, further confirmed by H&E histological analysis, immunofluorescence and immunohistochemistry mechanism experiments. This research lays the foundation for the manufacture of novel molecules that combine chemical and photodynamic strategies.

11.
Small ; 20(9): e2306742, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37840450

RESUMEN

Artificial photosynthesis can convert carbon dioxide into high value-added chemicals. However, due to the poor charge separation efficiency and CO2 activation ability, the conversion efficiency of photocatalytic CO2 reduction is greatly restricted. Ultrathin 2D photocatalyst emerges as an alternative to realize the higher CO2 reduction performance. In this review, the basic principle of CO2 photoreduction is introduced, and the types, advantages, and advances of 2D photocatalysts are reviewed in detail including metal oxides, metal chalcogenides, bismuth-based materials, MXene, metal-organic framework, and metal-free materials. Subsequently, the tactics for improving the performance of 2D photocatalysts are introduced in detail via the surface atomic configuration and electronic state tuning such as component tuning, crystal facet control, defect engineering, element doping, cocatalyst modification, polarization, and strain engineering. Finally, the concluding remarks and future development of 2D photocatalysts in CO2 reduction are prospected.

12.
Adv Healthc Mater ; 13(9): e2303845, 2024 04.
Artículo en Inglés | MEDLINE | ID: mdl-38117032

RESUMEN

Quantitative fluorescence immunoassay is essential for the construction of biosensing mechanisms and the quantification of trace markers. But the interference problems caused by low fluorescence efficiency and broad fluorescence spectrum of fluorescent probes have hindered the continued development of ratiometric fluorescence sensing in biosensing. Perovskite materials, with ultra-high color purity (FWHM < 30 nm) and photoluminescence quantum yield (PLQY) (close to 100%), are expected to be next-generation fluorescent probes. However, poor water stability and biocompatibility are still non-negligible in biosensor applications. In this work, hyperstatic perovskite fluorescent microspheres prepared by swelling-shrinking method can be used as ratiometric fluorescence signals and biological immunoassay platforms. Meanwhile, inspired by p-aminophenol (AP) controlled synthesis and the catalytic reaction of 4-aminophenol phosphate (APP) triggered by alkaline phosphatase (ALP), a strategy to prepare fluorescent nanoparticles as fluorescence signals for ALP detection is proposed. Most importantly, it is proposed for the first time to combine this enzymatic fluorescence with perovskite materials using covalent linkage to create a novel cascade immunoassay and use it for quantitative and visualization determination of hepatitis B surface antigen (HBsAg) for application verification. These results indicate the biosensing potential of perovskite materials and provide a pathway for high sensitivity enzyme detection and enzyme triggered immune detection.


Asunto(s)
Técnicas Biosensibles , Compuestos de Calcio , Nanopartículas , Óxidos , Puntos Cuánticos , Titanio , Colorantes Fluorescentes , Espectrometría de Fluorescencia/métodos , Fosfatasa Alcalina , Inmunoensayo , Técnicas Biosensibles/métodos
13.
J Colloid Interface Sci ; 658: 714-727, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38141393

RESUMEN

This work developed a novel chalcopyrite (CuFeS2) incorporated catalytic ceramic membrane (CFSCM), and comprehensively evaluated the oxidation-filtration efficiency and mechanism of CFSCM/peroxymonosulfate (PMS) for organics removal and membrane fouling mitigation. Results showed that PMS activation was more efficient in the confined membrane pore structure. The CFSCM50/PMS filtration achieved almost complete removal of 4-Hydroxybenzoic acid (4-HBA) under the following conditions: pH = 6.0, CPMS = 0.5 mM, and C4-HBA = 10 mg/L. Meanwhile, the membrane showed good stability after multiple uses. During the reaction, SO4•- and •OH were generated in the CFSCM50/PMS system, and SO4•- was considered to be the dominant reactive species for pollutant removal. The roles of copper, iron, and sulfur species, as well as the possible catalytic mechanism were also clarified. Besides, the CFSCM50/PMS catalytic filtration exhibited excellent antifouling properties against NOM with reduced reversible and irreversible fouling resistances. The Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory analysis showed an increased in repulsive energy at the membrane-foulant interface in the CFSCM50/PMS system. Membrane fouling model analysis indicated that standard blocking was the dominant fouling pattern for CFSCM50/PMS filtration. Overall, this work demonstrates an efficient catalytic filtration process for foulants removal and outlines the synergy of catalytic oxidation and interface interaction.

14.
Mikrochim Acta ; 191(1): 22, 2023 12 13.
Artículo en Inglés | MEDLINE | ID: mdl-38091089

RESUMEN

A paper-based electrochemical dual-function biosensor capable of determining pH and TCO2 was synthesized for the first time using an iridium oxide pH electrode and an all-solid-state ion electrode (ASIE). In the study, to obtain highly reliable results, the biosensor was equipped with a real-time pH correction function before TCO2 measurements. Compared to traditional liquid-filling carbon dioxide detection sensors, the utilization of ferrocene endows our novel sensor with abundant positive sites, and thus greatly improves its performance. Conversely, the introduction of MXene with conductivity close to that of metals reduces electrode resistance, which is beneficial for accelerating the electrochemical reaction of the sensor and reducing LOD. After optimization, the detection range of TCO2 is 0.095 nM-0.66 M, with a detection limit of as low as 0.023 nM. In addition, the sensor was used in real serum sample-spiked recovery experiments and comparison experiments with existing clinical blood gas analyzers, which confirmed the effectiveness of its clinical application. This study provides a method for the rational design of paper-based electrochemical biosensors and a new approach for the clinical detection of blood carbon dioxide.


Asunto(s)
Técnicas Biosensibles , Dióxido de Carbono , Técnicas Electroquímicas/métodos , Técnicas Biosensibles/métodos , Electrodos
15.
Commun Biol ; 6(1): 1211, 2023 11 28.
Artículo en Inglés | MEDLINE | ID: mdl-38017066

RESUMEN

3D spheroids have emerged as powerful drug discovery tools given their high-throughput screening (HTS) compatibility. Here, we describe a method for generating functional neural spheroids by cell-aggregation of differentiated human induced pluripotent stem cell (hiPSC)-derived neurons and astrocytes at cell type compositions mimicking specific regions of the human brain. Recordings of intracellular calcium oscillations were used as functional assays, and the utility of this spheroids system was shown through disease modeling, drug testing, and formation of assembloids to model neurocircuitry. As a proof of concept, we generated spheroids incorporating neurons with Alzheimer's disease-associated alleles, as well as opioid use disorder modeling spheroids induced by chronic treatment of a mu-opioid receptor agonist. We reversed baseline functional deficits in each pilot disease model with clinically approved treatments and showed that assembloid activity can be chemogenetically manipulated. Here, we lay the groundwork for brain region-specific neural spheroids as a robust functional assay platform for HTS studies.


Asunto(s)
Células Madre Pluripotentes Inducidas , Humanos , Encéfalo , Diferenciación Celular/fisiología , Neuronas , Ensayos Analíticos de Alto Rendimiento/métodos
16.
Chemosphere ; 344: 140347, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37793552

RESUMEN

Photocatalytic degradation of pollutants is considered a promising approach for wastewater treatment, but is hampered by low efficiency and limited understanding of degradation pathways. A novel oxygen-doped porous g-C3N4/oxygen vacancies-rich BiOCl (OCN/OVBOC) heterostructure was prepared for photocatalytic degradation of bisphenol A (BPA). The synergistic defect and doping engineering favor the formation of strong bonded interface for S-scheme mechanism. Among them, 0.3 OCN/OVBOC showed the most excellent degradation rate, which was 8 times and 4 times higher than that of pure g-C3N4 and BiOCl, respectively. This excellent performance is mainly attributed to the significantly enhanced charge separation via strong bonded interface and redox capability of the S-scheme heterojunction structure, by tuning the coordination excitation and electron localization of the catalyst via O doping and vacancies. This work provides important insights into the role of synergistic defect and doping engineering in facilitating the formation of strong bonded S-scheme heterojunction and ultimately sheds new light on the design of efficient photocatalysts.


Asunto(s)
Electrones , Contaminantes Ambientales , Oxígeno , Porosidad
17.
Int J Mol Sci ; 24(9)2023 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-37175928

RESUMEN

Thermal insulating composites are indispensable in electronic applications; however, their poor thermal conductivity and flexibility have become bottlenecks for improving device operations. Hexagonal boron nitride (BN) has excellent thermal conductivity and insulating properties and is an ideal filler for preparing thermally insulating polymer composites. In this study, we report a method to fabricate BN/polyurethane (PU) composites using an improved nonsolvent-induced phase separation method with binary solvents to improve the thermal performance and flexibility of PU. The stress and strain of BN60/PU are 7.52 ± 0.87 MPa and 707.34 ± 38.34%, respectively. As prepared, BN60/PU composites with unordered BN exhibited high thermal conductivity and a volume resistivity of 0.653 W/(m·K) and 23.9 × 1012 Ω·cm, which are 218.71 and 39.77% higher than that of pure PU, respectively. Moreover, these composite films demonstrated a thermal diffusion ability and maintained good integrity after 1000 bending cycles, demonstrating good mechanical and thermal reliability for practical use. Our findings provide a practical route for the production of flexible materials for efficient thermal management.


Asunto(s)
Electrónica , Poliuretanos , Reproducibilidad de los Resultados , Conductividad Térmica
18.
Int J Spine Surg ; 17(3): 356-363, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37230800

RESUMEN

BACKGROUND: Ossification of the posterior longitudinal ligament (OPLL) may cause cervical myelopathy. In its multilevel form, it may not be easy to manage. Minimally invasive endoscopic posterior cervical decompression may be an alternative to traditional laminectomy surgery. METHODS: Thirteen patients with multilevel OPLL and symptomatic cervical myelopathy were treated with endoscopic spine surgery from January 2019 to June 2020. In this consecutive observational cohort study, pre- and postoperative Japanese Orthopaedic Association (JOA) score and Neck Disability Index (NDI) were analyzed at a final follow-up of 2 years postoperatively. RESULTS: There were 13 patients consisting of 3 women and 10 men. The patient's average age was 51.15 years. At the final 2-year follow-up, the JOA score improved from a preoperative value of 10.85 ± 2.91 to 14.77 ± 2.13 postoperatively (P < 0.001). The corresponding NDI scores decreased from 26.61 ± 12.88 to 11.12 ± 10.85 (P < 0.001). There were no infections, wound complications, or reoperations. CONCLUSION: Direct posterior endoscopic decompression for multilevel OPLL is feasible in symptomatic patients when executed at a high skill level. While 2-year outcomes were encouraging and on par with historic data obtained with traditional laminectomy, future studies will need to show whether any long-term shortcomings exist.

19.
IEEE Trans Med Imaging ; 42(6): 1859-1874, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37022266

RESUMEN

The long acquisition time has limited the accessibility of magnetic resonance imaging (MRI) because it leads to patient discomfort and motion artifacts. Although several MRI techniques have been proposed to reduce the acquisition time, compressed sensing in magnetic resonance imaging (CS-MRI) enables fast acquisition without compromising SNR and resolution. However, existing CS-MRI methods suffer from the challenge of aliasing artifacts. This challenge results in the noise-like textures and missing the fine details, thus leading to unsatisfactory reconstruction performance. To tackle this challenge, we propose a hierarchical perception adversarial learning framework (HP-ALF). HP-ALF can perceive the image information in the hierarchical mechanism: image-level perception and patch-level perception. The former can reduce the visual perception difference in the entire image, and thus achieve aliasing artifact removal. The latter can reduce this difference in the regions of the image, and thus recover fine details. Specifically, HP-ALF achieves the hierarchical mechanism by utilizing multilevel perspective discrimination. This discrimination can provide the information from two perspectives (overall and regional) for adversarial learning. It also utilizes a global and local coherent discriminator to provide structure information to the generator during training. In addition, HP-ALF contains a context-aware learning block to effectively exploit the slice information between individual images for better reconstruction performance. The experiments validated on three datasets demonstrate the effectiveness of HP-ALF and its superiority to the comparative methods.


Asunto(s)
Aprendizaje Profundo , Humanos , Imagen por Resonancia Magnética/métodos , Artefactos , Percepción Visual , Procesamiento de Imagen Asistido por Computador/métodos
20.
Int J Mol Sci ; 24(5)2023 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-36902465

RESUMEN

Reinforcement of polymer nanocomposites can be achieved by the selection of the appropriate fabrication method, surface modification, and orientation of the filler. Herein, we present a nonsolvent-induced phase separation method with ternary solvents to prepare thermoplastic polyurethane (TPU) composite films with excellent mechanical properties using 3-Glycidyloxypropyltrimethoxysilane-modified cellulose nanocrystals (GLCNCs). ATR-IR and SEM analyses of the GLCNCs confirmed that GL was successfully coated on the surface of the nanocrystals. The incorporation of GLCNCs in TPU resulted in the enhancement of the tensile strain and toughness of pure TPU owing to the enhanced interfacial interactions between them. The GLCNC-TPU composite film had tensile strain and toughness values of 1740.42% and 90.01 MJ/m3, respectively. Additionally, GLCNC-TPU exhibited a good elastic recovery rate. CNCs were readily aligned along the fiber axis after the spinning and drawing of the composites into fibers, which further improved the mechanical properties of the composites. The stress, strain, and toughness of the GLCNC-TPU composite fiber increased by 72.60%, 10.25%, and 103.61%, respectively, compared to those of the pure TPU film. This study demonstrates a facile and effective strategy for fabricating mechanically enhanced TPU composites.


Asunto(s)
Nanopartículas , Poliuretanos , Poliuretanos/química , Silanos , Celulosa/química , Polímeros/química , Nanopartículas/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA