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1.
Mol Cell Biochem ; 476(1): 303-310, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32989626

RESUMEN

Although tooth loss is a known risk factor of cognitive function, whether and how the chewing-side preference (CSP) affects memory impairment still remains unclear. This study evaluates the behavior changes in mice after the loss of teeth on one side and explores the role of serotonin (5-HT) and brain-derived neurotrophic factor (BDNF) signal pathway within these changes. To this end, CSP mouse models with either the removal of left unilateral molars (CSP-L) or right unilateral molars (CSP-R) were established. Morris water maze test and passive avoidance test were performed to evaluate the mice's learning and memory capacity in the 4th and 8th weeks. The correlation between CSP and brain function changes was validated with changes in 5-HT and BDNF levels. CSP mice's cognitive function was found to be decreased, along with a significant decline in 5-HT1A level, especially in CSP-R mice. BDNF and TrkB levels in CSP-R mice were also significantly lowered. These findings suggest that CSP results in memory impairment, which is associated with the 5-HT-BDNF signaling pathway.


Asunto(s)
Factor Neurotrófico Derivado del Encéfalo/análisis , Masticación , Trastornos de la Memoria , Serotonina/análisis , Transducción de Señal , Animales , Reacción de Prevención , Conducta Animal , Cognición , Hipocampo , Masculino , Aprendizaje por Laberinto , Glicoproteínas de Membrana/metabolismo , Memoria , Ratones , Proteínas Tirosina Quinasas/metabolismo , Temperatura , Diente/fisiología
2.
BMC Pediatr ; 21(1): 177, 2021 04 16.
Artículo en Inglés | MEDLINE | ID: mdl-33863305

RESUMEN

BACKGROUND: Dental procedures under general anesthesia (DGA) was found to improve the oral health-related quality of children's life. However, some parents and pediatricians expressed concern about the neurotoxicity of general anesthesia. The purpose of this trial was to whether DGA in children has an adverse effect on neurocognition. METHODS: In this prospective, assessor-masked, controlled, equivalence trial, we recruited 340 children younger than 7 years who were undergoing caries treatment between Feb 1, 2019, and Aug 31, 2019, without factors affecting neurodevelopment. They received either sevoflurane-based general anesthesia or awake-local anesthesia. The Wechsler Preschool and Primary Scale of Intelligence-Fourth Edition was used to evaluate the neurocognitive function of children at 6 months after surgery, and the Full-Scale IQ (FSIQ) was selected as the primary outcome. The predefined clinical equivalence margin was 5 (1/3 SD of FSIQ score). If the 95% CI of the difference between the average FSIQ score of the two groups is within - 5 to + 5, then the two groups are equivalent. RESULTS: The outcome data were obtained from 129 children in the general anesthesia group and 144 in the local anesthesia group. The median length of general anesthesia was 130 min (IQR 110-160). The mean FSIQ score in the general anesthesia group was 103·12 (SD 8.94), and the mean of the local anesthesia group was 103·58 (SD 8.40). There was equivalence in means of FSIQ score between the two groups (local minus general anesthesia 0.46, 95% CI - 2.35 to 1.61). There was no significant difference in FSIQ scores between different age groups and different anesthesia durations. Only the mother's education could affect the primary outcome. CONCLUSIONS: In this trial, prolonged DGA with a sevoflurane-only anesthetic in preschool children, does not adversely affect neurocognitive function at 6 months after surgery compared with awake-local anesthesia. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800015216 . Registered Mar 15 2018.


Asunto(s)
Anestesia General , Salud Bucal , Anestesia General/efectos adversos , Preescolar , Odontología , Humanos , Estudios Prospectivos , Sevoflurano
3.
Langmuir ; 32(7): 1828-35, 2016 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-26818185

RESUMEN

We demonstrate that the lamella-forming polystyrene-block-poly(N-methyl-4-vinylpyridinium iodine) (PS-b-P4VPQ), with similar sizes of the PS and P4VPQ blocks, can be dispersed in the aqueous solutions by forming lipid/PS-b-P4VPQ multilamellae. Using small-angle neutron scattering (SANS) and 1,2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (d62-DPPC) in D2O, a broad correlation peak is found in the scattering profile that signifies the formation of the loosely ordered d62-DPPC/PS-b-P4VPQ multilamellae. The thicknesses of the hydrophobic and hydrophilic layers of the d62-DPPC/PS-b-P4VPQ multilamellae are close to the PS layer and the condensed brush layer thicknesses as determined from previous neutron reflectometry studies on the PS-b-P4VPQ monolayer at the air-water interface. Such well-dispersed d62-DPPC/PS-b-P4VPQ multilamellae are capable of forming multilamellae with DNA in aqueous solution. It is found that the encapsulation of DNA in the hydrophilic layer of the d62-DPPC/PS-b-P4VPQ multilamellae slightly increases the thickness of the hydrophilic layer. Adding CaCl2 can enhance the DNA adsorption in the hydrophilic brush layer, and it is similar to that observed in the neutron reflectometry study of the DNA adsorption by the PS-b-P4VPQ monolayer.


Asunto(s)
ADN/química , Lípidos/química , Difracción de Neutrones , Polímeros/química , Poliestirenos/química , Compuestos de Piridinio/química , Dispersión del Ángulo Pequeño , Modelos Moleculares , Conformación Molecular
4.
J Comput Aided Mol Des ; 30(7): 533-9, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27480697

RESUMEN

In drug discovery, protonation states and tautomerization are easily overlooked. Through a Merck-Rutgers collaboration, this paper re-examined the initial settings and preparations for the Thermodynamic Integration (TI) calculation in AMBER Free-Energy Workflows, demonstrating the value of careful consideration of ligand protonation and tautomer state. Finally, promising results comparing AMBER TI and Schrödinger FEP+ are shown that should encourage others to explore the value of TI in routine Structure-based Drug Design.


Asunto(s)
Diseño de Fármacos , Descubrimiento de Drogas , Protones , Humanos , Ligandos , Modelos Moleculares , Politetrafluoroetileno/química , Unión Proteica , Termodinámica
5.
Med Sci Monit ; 21: 1617-24, 2015 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-26038188

RESUMEN

BACKGROUND: Interleukin-1ß (IL-1ß) is an important inflammatory cytokine. The associations between IL-1ß gene -511C>T/+3954C>T polymorphisms and aggressive periodontitis (AgP) susceptibility have been conflicting. We therefore conducted a meta-analysis to investigate the association of IL-1ß genetic polymorphisms with susceptibility to AgP. MATERIAL AND METHODS: PubMed and Embase electronic databases were searched for relevant studies. Odds ratios (ORs) with 95% confidence interval (CIs) were used to assess the association between IL-1ß polymorphisms and AgP risk. Heterogeneity, publication bias, and sensitivity analysis were performed to guarantee the statistical power. RESULTS: Twenty published studies involving 965 patients and 1234 control subjects were included. No significant association between IL-1ß polymorphisms and AgP was found. For -511C>T (T vs. C: OR=0.966, 95%CI=0.696-1.341, P=0.869; CT vs. CC: OR=0.936, 95%CI=0.761-1.151; TT vs. CC: OR=0.892, 95%CI=0.464-1.715, P=0.719; CT+TT vs. CC: OR=1.026, 95%CI=0.795-1.323; TT vs. CC+CT: OR=0.864, 95%CI=0.436-1.713). For +3954C>T (T vs. C: OR=1.069, 95%CI=0.901-1.268; CT vs. CC: OR=0.921, 95%CI=0.699-1.212; TT vs. CC: OR=1.064, 95%CI=0.747-1.515; CT+TT vs. CC: OR=0.990, 95%CI=0.764-1.283; TT vs. CC+CT: OR=1.229, 95%CI=0.919-1.643). Subgroup analyses were conducted with HWE, ethnicity, and study design, and no significant association was detected. CONCLUSIONS: These results demonstrate that IL-1ß -511C>T and +3954C>T polymorphisms are not the risk factors for developing AgP.


Asunto(s)
Periodontitis Agresiva/genética , Predisposición Genética a la Enfermedad/genética , Interleucina-1beta/genética , Polimorfismo de Nucleótido Simple/genética , Estudios de Asociación Genética , Humanos , Oportunidad Relativa , PubMed
6.
Soft Matter ; 10(13): 2313-9, 2014 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-24795965

RESUMEN

Disc-shaped bicelles are formed by mixing long-chain lipids with short-chain lipids at suitable molar ratios and they have a relatively uniform size, typically around a few tens of nanometers in diameter. Different from the typically formulated cationic or anionic liposome­DNA complexes, which are used as nonviral vectors for improving the transfection efficiency of gene therapy, a novel way of packing the DNA can be developed by using the much smaller disc-like bicelles. We demonstrate that anionic lipid bicelle-ion­DNA (AB­DNA) complexes can be formed with the help of divalent ions. Multi-stacked AB­DNA complexes can be formed with diameters of around 50­100 nm and lengths of around 50­150 nm as revealed by TEM. Using the anionic lipid­DNA complexes has the advantage of lower cytotoxicity than using cationic lipids. The interaction of DNA with anionic bicelles was investigated by SAXS. It was found that the anionic bicelle could not form stable complexes with DNA at low calcium ion concentrations, such as 1 mM. The AB­DNA complexes can be formed in the investigated range of 10 mM to 100 mM calcium ion concentrations. However, for an equal anionic lipid charge and DNA charge system, an ion-membrane phase (multilamellar vesicles) would gradually appear as the calcium ion concentration is increased above a critical concentration. It indicates that DNA could be packed closer at above the critical divalent ion concentration. If more DNA is added to such a two-phase coexistence system (originally with the total anionic lipid charge equal to that of DNA), the ion-membrane phase could be transformed into the AB­DNA complexes. As a result, more DNA can be packed in the form of AB­DNA complexes at above the critical calcium ion concentration.


Asunto(s)
ADN/química , Liposomas/química , Calcio/química , ADN/metabolismo , Iones/química , Liposomas/metabolismo , Simulación de Dinámica Molecular , Nanoestructuras/química , Nanoestructuras/ultraestructura , Tamaño de la Partícula
7.
Int J Biol Macromol ; 254(Pt 1): 127610, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38287579

RESUMEN

In this work, microcrystalline cellulose (MCC) treated polyamide 66 (PA66) textiles were coated with green and naturally abundant polysaccharides specifically, chitosan (CS) and sodium alginate (SA) together with phytic acid (PA) via layer by layer (LbL) deposition. The prime focus of such treatment was to intensify both the hydrophilic and flame retardant properties of PA66 fabric substrates. Subsequently, the prepared coatings were further subjected to cross-linking modification by dipping them into the barium (Ba) salt solution. Obtained results indicated that the MCC-modified PA66 exhibited a water contact angle (WCA) value of 00 and revealed a drop in peak heat release rate (pHRR) up to 31 % with complete suppression of melt-dripping. Meanwhile, the Ba-ion-induced cross-linking treatment further escalated this reduction up to 36 % by adding enhanced thermal stability, improved char quality along better wash durability of as prepared coatings. In addition, the combined modification of PA66 textiles with MCC and Ba-ion handed a superb enhancement of physical properties like tensile strength by ca. 50 % compared to the pure PA66. Thus, this MCC-assisted surface modification paves the way for a new kind of greener treatment of PA66 textiles in attaining superior hydrophilic and flame retardant properties of the same.


Asunto(s)
Retardadores de Llama , Nylons , Textiles , Polielectrolitos , Celulosa , Interacciones Hidrofóbicas e Hidrofílicas
8.
Adv Healthc Mater ; 13(12): e2303631, 2024 05.
Artículo en Inglés | MEDLINE | ID: mdl-38278138

RESUMEN

Currently, the secondary development and modification of clinical drugs has become one of the research priorities. Researchers have developed a variety of TME-responsive nanomedicine carriers to solve certain clinical problems. Unfortunately, endogenous stimuli such as reactive oxygen species (ROS), as an important prerequisite for effective therapeutic efficacy, are not enough to achieve the expected drug release process, therefore, it is difficult to achieve a continuous and efficient treatment process. Herein, a self-supply ROS-responsive cascade polyprodrug (PMTO) is designed. The encapsulation of the chemotherapy drug mitoxantrone (MTO) in a polymer backbone could effectively reduce systemic toxicity when transported in vivo. After PMTO is degraded by endogenous ROS of the TME, another part of the polyprodrug backbone becomes cinnamaldehyde (CA), which can further enhance intracellular ROS, thereby achieving a sustained drug release process. Meanwhile, due to the disruption of the intracellular redox environment, the efficacy of chemotherapy drugs is enhanced. Finally, the anticancer treatment efficacy is further enhanced due to the mild hyperthermia effect of PMTO. In conclusion, the designed PMTO demonstrates remarkable antitumor efficacy, effectively addressing the limitations associated with MTO.


Asunto(s)
Acroleína/análogos & derivados , Mitoxantrona , Especies Reactivas de Oxígeno , Mitoxantrona/química , Mitoxantrona/farmacología , Mitoxantrona/farmacocinética , Especies Reactivas de Oxígeno/metabolismo , Animales , Humanos , Ratones , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Hipertermia Inducida/métodos , Profármacos/química , Profármacos/farmacología , Acroleína/química , Acroleína/farmacología , Ratones Endogámicos BALB C , Liberación de Fármacos , Femenino , Ratones Desnudos , Portadores de Fármacos/química , Polímeros/química
9.
Int J Biol Macromol ; 239: 124252, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-36996951

RESUMEN

Rising concerns about the toxic effects and environmental issues associated with various fireproof treatments on textiles have led to a demand for "green" materials. Chitosan (CS) is an amino polysaccharide green, recyclable, and non-toxic highly biocompatible biopolymer that consists of multiple hydroxyl groups and has a wide range of applications, including as a flame retardant additive. In this study, an eco-friendly bio-based formaldehyde-free flame retardant containing a higher level of phosphorus and nitrogen in phytic acid ammonia (PAA) was synthesized to amplify the most plentiful green chitosan (CS)-modified polyamide 66 (PA66) fabric surface through a simple pad-dry-cure technique for the improvement of durable flame retardancy with hydrophilicity. The findings revealed that each UV-grafted CS fabric could entirely stop the melt-dripping tendency during the vertical burning (UL-94) test and reached a V-1 rating. Meanwhile, limiting oxygen index (LOI) testing showed a rapid increase from 18.5 % to 24 % for the PA66 control and the PAA-treated (i.e., PA66-g-5CS-PAA) fabric samples, respectively. Moreover, compared to the PA66 control sample, a dramatic decrease in the peak heat release rate (PHRR), fire growth rate (FGR), and total heat release (THR) by approximately over 52 %, 0.63 %, and 19.7 %, respectively, was observed for the PA66-g-5CS-PAA fabric sample. Additionally, this arrangement of PAA catalyzed the charring of grafted CS and acted as a condensed phase flame retardant, resulting in a significant improvement in char yield% in both air and N2 atmospheres for the PA66-g-5CS-PAA fabric sample in TGA. In addition, only the lower grafting ratio of CS with PAA-treated fabric sample (i.e., PA66-g-2CS-PAA) could encourage it to gain its lowest water contact angle of 00, as well as impersonating a positive effect in improving the flame retardant coating durability in washing and sustaining even after 10 home laundering cycles. This phenomenon suggests that an actual hydrophilic and durable flame retardant finishing procedure for polyamide 66 fabrics might be applied with the novel, plentiful, sustainable, and environmentally friendly bio-based green PAA ingredient.


Asunto(s)
Quitosano , Retardadores de Llama , Nylons , Fósforo , Textiles , Amoníaco , Ácido Fítico
10.
Chemosphere ; 311(Pt 1): 137058, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36419266

RESUMEN

As one of the most widely used polymers, the intrinsic brittleness and high flammability bring about a stringent requirement for the practical application of epoxy resins (EPs). It is difficult to toughen EP without compromising its mechanical and thermal properties for many conventional toughening agents. Here, a novel furan-derived bio-based polyphosphazene (PFMP) with a flexible backbone and rigid side groups was prepared by the nucleophilic substitution reaction between polydichlorophosphazene (PDCP) and furfuralcohol. The resultant PFMP was incorporated into EP to realize exceptional toughening, strengthening, and flame retardant function. By adding 15% of PFMP, the limit oxygen index value is from 25% (EP) to 33% (EP/PFMP-15) and reaches the UL-94 V-0 rating. According to the cone calorimeter results, EP/PFMP-15 exhibits exceedingly reduced peak heat release rate (pHRR) (50.2%) and total heat release (THR) (49.6%). The significantly increased fire performance index (FPI) and decreased fire growth rate index (FIGRA) of EP/PFMP-15 demonstrate an improvement in its flame retardancy. The catalytic carbonization effect (condensed phase) and radical quenching effect (gas phase) of PFMP account for the greatly improved flame retardancy. Moreover, the impact and tensile tests indicate that PFMP can ameliorate the mechanical performance of EP with a maximum increase of impact strength (111.8%) and elongation at break (35.2%) for EP/PFMP-5. With 15% PFMP added, the tensile strength of EP/PFMP-15 increases by 40.4%. This work demonstrates that PFMP is expected to overcome shortcomings (flammability, toughness, and strength) of EP and spread its applied fields.


Asunto(s)
Resinas Epoxi , Retardadores de Llama , Biomasa , Compuestos Organofosforados
11.
Shanghai Kou Qiang Yi Xue ; 32(3): 323-327, 2023 Jun.
Artículo en Zh | MEDLINE | ID: mdl-37803992

RESUMEN

PURPOSE: To investigate the difference in the retention effect of 3D printing resin splint and Hawley retainer combined with lingual retention wire in periodontal disease patients after orthodontic treatment. METHODS: Forty patients who finished orthodontic treatment for periodontal disease from January 2021 to February 2022 were selected and divided into experimental group and control group according to the random number table method, with 20 patients in each group. Patients in the experimental group used 3D printing resin splint for retention, while patients in the control group used Hawley retainer combined with a lingual retention wire for retention. The chair-side operation time of the retainers was recorded for both groups. The maxillary and mandibular cuspid width, molar width, overjet, overbite and irregularity index were measured at 1 month and 6 months after orthodontic treatment in both groups. Statistical analysis was performed with SPSS 12.0 software package. RESULTS: The mean time for chair-side manipulation of experimental group and control group was 8.23, 11.17 min, respectively. The difference between the two groups was statistically significant (P<0.05) when comparing the width of the maxillary and mandibular cusps, the width of the molars, overjet, overbite and the irregularity index after 1 month and 6 months of wear of the retainers, which were significantly greater in the experimental group than in the control group at 6 months(P<0.05). CONCLUSIONS: 3D printing resin splint, with short chair-side manipulation time, was more effective than Hawley retainer combined with a lingual retention wire, and the efficacy of both groups was otherwise generally consistent.


Asunto(s)
Maloclusión Clase II de Angle , Sobremordida , Enfermedades Periodontales , Humanos , Férulas (Fijadores) , Retenedores Ortodóncicos/efectos adversos , Diseño de Aparato Ortodóncico
12.
Shanghai Kou Qiang Yi Xue ; 31(2): 198-200, 2022 Apr.
Artículo en Zh | MEDLINE | ID: mdl-36110080

RESUMEN

PURPOSE: To compare the effect of different root canal preparation methods on the incidence of interappointment emergencies (IAE) and root canal filling. METHODS: A total of 96 teeth requiring root canal therapy due to pulpitis or periapical periodontitis from August 2018 to August 2021 were selected. They were randomly divided into 2 groups: MT group was treated with Mtwo root canal preparation method modified by Mtwo machine nickel-titanium file, while synchronous group was treated with modified Mtwo preparation method and synchronous root canal length measurement. After root canal preparation, the trial point film was taken, calcium hydroxide was used to seal the root canal, and routine thermoplasticizied gutta-percha root canal filling was performed during the follow-up visit. SPSS 22.0 software package was used to analyze the incidence of IAE and filling effect after root canal therapy. RESULTS: There was no significant difference in the incidence of IAE between the two groups immediately after operation, three days and 1 week after operation(P>0.05); the incidence of IAE in synchronous group was significantly lower than that in MT group at 1 and 2 days after operation(P<0.05). The qualified rate of root canal filling in synchronous group was significantly higher than that in MT group (P<0.05). CONCLUSIONS: Synchronous method can reduce mechanical stimulation of apical area during root canal preparation, strictly control the working length of root canal and maintain apical barrier, thus reducing the incidence of IAE and effectively improving the qualification rate of root canal filling.


Asunto(s)
Urgencias Médicas , Tratamiento del Conducto Radicular , Hidróxido de Calcio , Gutapercha , Humanos , Níquel , Tratamiento del Conducto Radicular/efectos adversos , Tratamiento del Conducto Radicular/métodos , Titanio , Resultado del Tratamiento
13.
J Colloid Interface Sci ; 626: 208-220, 2022 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-35797867

RESUMEN

It is of great importance to fabricate flexible polyurethane foam (FPUF) with superior mechanical properties and flame retardancy for practical applications. Herein, organosilicon and phenyl phosphorus compounds were synthesized and grafted on the surface of Ti3C2Tx (Ti3C2Tx@BPA@PCL) via in-situ polymerization. Then, the FPUF composites were fabricated, combining intrinsic flame retardancy (9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide-diethanolamine: DH-DOPO) (addition amount: 20 wt%) and Ti3C2Tx@BPA@PCL (addition amount: 4 wt%). Attributed to the rigid structure of Ti3C2Tx@BPA@PCL, the tensile strength and compression strength of FPUF showed 24.0% and 253% increase, respectively. In addition, anti-fatigue properties of FPUF composites during the cyclical test were dramatically enhanced. In contrast to pure FPUF, 36.1% and 44.0% reductions in peak heat release rate (pHRR) and total heat release (THR) were achieved for the FPUF containing Ti3C2Tx@BPA@PCL and DH-DOPO, the production rate of carbon dioxide (CO2) and carbon oxide (CO) also decreased by 40.3% and 52.1%, respectively. FPUF4 showed self-extinguishing behavior, and passed the vertical burning test (VBT). This work provides a facile approach to preparing high-performance FPUF with enhanced mechanical property and flame retardancy.


Asunto(s)
Retardadores de Llama , Óxidos , Poliuretanos , Titanio
14.
Carbohydr Polym ; 291: 119488, 2022 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-35698361

RESUMEN

Nacre mimetic coatings are attractive candidates for food packaging, electronics, textiles, protective insulation, and flame retardant materials. Inspired by the hierarchical structure of nacre, we present an environmentally friendly strategy to construct robust and flame retardant films using chitin, which is an abundantly available biopolymer. Chitin was phosphorylated to make it water-soluble. Multilayered films were constructed by assembling poly (vinyl alcohol) (PVA), graphene oxide (GO) nanosheets, phosphorylated chitin (p. chitin), and laponite (LAP) via Layer-by-Layer (LbL) and vacuum-assisted filtration (VAF) assemblies. SEM micrographs revealed the nacre-like layered structure while photographic images showed a similar sheen to that of the mother of pearl. The fabricated coatings possess good mechanical properties with a reduced modulus of 25.53 GPa and hardness of 1.45 GPa. In addition, multilayered films exhibited iridescence and attractive flame retardancy. We believe that our strategy of embedding chitin offers cost-effective and environmentally friendly coatings for textiles, food packaging, barrier, and electronic materials.


Asunto(s)
Retardadores de Llama , Nácar , Biomimética , Quitina/química , Nácar/química , Alcohol Polivinílico/química
15.
Chemosphere ; 305: 135504, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35777539

RESUMEN

This work aims at revealing and optimizing the mechanism, to promote the design of phosphorus-based flame retardants (PFRs) for controlling the spread of fire risk caused by the continuous spread of polymers. Herein, we synthesized about 10 nm TiO2 grown in situ on the surface of BP through a simple hydrothermal procedure to introduce it into epoxy (EP/BP-TiO2). In the first place, EP/BP-TiO22.0 nanocomposite achieves a reduction of 58.96% and 50.35% in PHRR and THR, respectively. Secondly, the pyrolysis of BP from Pn to P4, P3 and P2 is revealed. As a guide, P4 is established as a characteristic product of the analytical model for evaluating the effects in the gas phase for BP-based hybrids. Finally, this work clarifies the enhancement path for BP-TiO2 is optimized for the capturing of OH· and H· radicals by P4(POx). Crucially, this study reveals and controls the mechanism of the BP-based hybrids at the molecular level, which is expected to provide a promising analytical model for broad market PFRs design to address the risks and challenges of casualties and ecology caused by composites fire.


Asunto(s)
Incendios , Retardadores de Llama , Nanocompuestos , Resinas Epoxi , Fósforo
16.
J Colloid Interface Sci ; 608(Pt 1): 142-157, 2022 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-34624762

RESUMEN

Owing to the lack of research on structure-activity relationship and interaction mechanism between unsaturated polyester resins (UPR) and flame retardants, it has been a big challenge to prepare high-efficiency flame retardants for UPR in industry. In this research, to explore structural rules of high-efficiency flame retardants, several polymeric flame retardants were synthesized with varied main-chain, side-chain, phosphorus valence states and contents of flame retardant elements. The thermal stabilities of flame retardants and UPR composites were firstly assessed. It has been found the interaction existed between flame retardants and UPR, through transesterification reaction and ß scission pathway in polyester and polystyrene chains. With only 15 wt% of PCH3-S, UPR composites can reach V0 rating in UL-94. The PHRR and THR values can be maximumly decreased by 71.66 % and 77.67 %, with 20 wt% of PB-S. It has been found flame retardants with sulfone group and + 3 valence state of phosphorus in molecular backbone can release SO2 and phosphorus containing compounds in gaseous phase, which diluted fuel fragments and catalyzed H⋅ and HO⋅ radical removal. The mechanism for improved flame retardancy of UPR composites with various polymeric flame retardants were discussed in detail. Some general rules for highly efficient flame retardant UPR can be summarized: First, gaseous phase flame retardant mechanism plays the major role in improvement of flame retardant performance of UPR composites; Second, the combination of + 3 valence state of phosphorus structures, higher phosphorus contents and sulfone groups effectively improves the flame retardant efficiency of flame retardants.


Asunto(s)
Retardadores de Llama , Fósforo , Poliésteres , Polímeros
17.
J Colloid Interface Sci ; 606(Pt 2): 1395-1409, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34492475

RESUMEN

As an antioxidant, hindered phenol scavenges free radicals. Due to the oxidative degradation of black phosphorus (BP) in the presence of water and oxygen, free radical quenching of hindered phenol antioxidants can solve this issue and improve the environmental stability and flame retardant efficiency of BP. Herein, hydroxyl-modified BP (BP-OH) with active groups on the surface was obtained by hydroxylation, and then the hindered phenol antioxidant was grafted onto the surface of BP-OH through an isophorone diisocyanate bridging covalent reaction to obtain hindered phenol-modified BP (BP-HPL). The fire hazard of thermoplastic polyurethane (TPU) can be significantly reduced by introducing BP-HPL into TPU. Adding 2 wt% BP-HPL can reduce the heat release rate and total heat release values of TPU by 49.9% and 49.0%, respectively. In addition, the reductions in smoke volume and carbon monoxide production were also significant. Compared with BP-OH, the environmental stability of BP-HPL is significantly improved. This work provides a reference for the application of BP in the field of fire safety and simultaneously achieves the improvement of the environmental stability and flame retardant performance of BP.


Asunto(s)
Antioxidantes , Fósforo , Radicales Libres , Fenoles , Poliuretanos
18.
Colloids Surf B Biointerfaces ; 209(Pt 2): 112209, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34814101

RESUMEN

Biodegradable poly-(lactide-coε-caprolactone) (PLCL) scaffolds have opened new perspectives for tissue engineering due to their nontoxic and fascinating functionality. Herein, a black phosphorus-based biodegradable material with a combination of promising enhanced hydrophilicity, shape recovery and osteodifferentiation properties was proposed. First, amino black phosphorous (BP-NH2) was prepared by a simple ball milling method. Then, L-lysine-modified black phosphorous (L-NH-BP) was formed by hydrogen bonding between L-lysine and amino BP and integrated into PLCL to form PLCL/L-NH-BP composite fibers. The scaffolds had excellent shape recovery and shape fixity properties. Moreover, based on gene expression and protein level assessment, the scaffolds could enhance the expression of alkaline phosphatase (ALP) and bone morphogenetic protein 2 (BMP2), simultaneously improving the mineralization ability of bone mesenchymal stem cells. Specifically, this new composite material was experimentally verified to be degradable under mild conditions. This strategy provided new insight into the design of multifunctional materials for diverse applications.


Asunto(s)
Nanofibras , Caproatos , Dioxanos , Interacciones Hidrofóbicas e Hidrofílicas , Lactonas , Lisina , Fósforo , Poliésteres , Ingeniería de Tejidos , Andamios del Tejido
19.
J Colloid Interface Sci ; 607(Pt 2): 1300-1312, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34583035

RESUMEN

Flexible polyurethane foam (FPUF) is the most used polyurethane, but the highly flammable characteristic limits its widespread usage. In this work, ZIF-8@Ti3C2Txwas synthesized to reduce the heat and toxic gases of FPUF. Flame-retardant FPUF was characterized by cone calorimeter (Cone), thermogravimetric analysis/fourier-transform infrared spectroscopy (TG-FTIR), tensileand compression tests. Compared with pure FPUF, these results showed that the peak of heat release rate (PHRR), total heat release (THR), CO and HCN of FPUF6 decreased by 46%, 69%, 27% and 43.5%, respectively. Moreover, the tensile and compression strength of FPUF6 demonstrated a 52% and 130% increment, respectively. The superior dual metal catalytical charring-forming effect and physical barrier effect of ZIF-8@Ti3C2Tx were achieved. In summary, a simple and reliable strategy for preparing flame-retardant FPUF with reinforced mechanical and fire safety properties was provided.


Asunto(s)
Retardadores de Llama , Poliuretanos , Gases , Poliuretanos/toxicidad , Titanio
20.
Food Res Int ; 160: 111623, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36076436

RESUMEN

This article describes the development of a novel liposome nanocarrier system. Carvacrol (Car) is first embedded in ß-cyclodextrin (ß-CD) by the freeze-drying method to form the ß-cyclodextrin-carvacrol inclusion compound (ß-CD-Car), and then ß-CD-Car liposomes (ß-CD-Car-LPs) and ß-CD-Car liposomes coated with S-layer proteins (SLPs) from Lactobacillus buchneri 20023 (SLP/ß-CD-Car-LPs) were prepared. The liposomes were characterized, and their stabilities, in vitro release characteristics, and antibacterial activities were investigated. Results showed that the fabricated liposome SLP/ß-CD-Car-LPs was nanosized, oval and homogenous, with the particle size of 229.1 ± 6.81 nm, the polydispersity index of 0.139, and the zeta potential of 27.9 mV. Measurements based on Triton X-100 resistance indicated that the SLP-coated liposomes were more stable than naked liposomes. The in vitro release study results showed that the rate of release from SLP-coated liposomes was much lower than that from uncoated liposomes. The minimum inhibitory activity (MIC) of SLP/ß-CD-Car-LPs (0.05 mg/mL) was 6.4 times higher than that of the free carvacrol (0.32 mg/mL) and was twice that of ß-CD-Car-LPs (0.1 mg/mL). In general, the stability, antibacterial activity, and sustained release effect of ß-CD-Car-LPs modified with SLPs were improved. Findings suggested that SLP-coated liposomes could be developed as a favorable delivery system for potential applications in the food industry.


Asunto(s)
Liposomas , beta-Ciclodextrinas , Antibacterianos/farmacología , Cimenos , Lactobacillus , Lipopolisacáridos , Glicoproteínas de Membrana
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