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1.
Am J Forensic Med Pathol ; 44(4): 345-349, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37549028

RESUMEN

ABSTRACT: 1,2-Dichloropropane (1,2-DCP) is a common industrial solvent and chemical intermediate that can cause acute poisoning to humans through exposure during its production and industrial use. The target organs of 1,2-DCP include the eyes, respiratory system, liver, kidney, central nervous system, and skin. Forensic identification of 1,2-DCP poisoning is difficult because of the lack of characteristic pathological changes. This article reports an autopsy case of acute 1,2-DCP poisoning caused by self-ingestion of rubber cement. A woman developed seizures and coagulation dysfunction after ingesting approximately 10 mL of rubber cement and died 43 hours later. Autopsy revealed generalized subcutaneous hemorrhage, cardiopulmonary multifocal hemorrhage, bronchopneumonia, severe cerebral edema, focal hepatic necrosis, granular deposition in the glomerular capsule and renal tubules, and delipidation of the adrenal cortex. These findings indicate that 1,2-DCP poisoning can induce central nervous system dysfunction, respiratory system damage, liver and kidney function damage, hemolytic anemia, disseminated intravascular coagulation, and adrenal damage. This case may provide useful perspectives for forensic identification of 1,2-DCP poisoning in the future.


Asunto(s)
Hidrocarburos Clorados , Intoxicación , Femenino , Humanos , Autopsia , Goma , Hemorragia , Ingestión de Alimentos
2.
Macromol Rapid Commun ; 42(20): e2100364, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34418202

RESUMEN

Developing an autonomous self-healing polyurethane (PU) elastomer with excellent mechanical properties and high ductility has attracted increasing attention. Nowadays, the synthesis of elastomers with excellent mechanical properties and rapid self-healing at room temperature faces a huge challenge. Herein, This work reports a new supramolecular PU with excellent mechanical properties and rapid self-healing at room temperature through the introduction of T-type chain extender into the supramolecular polymer chain. The introduction of T-chain extender can be used to enhance the mechanical strength of PU, and the multiple hydrogen bonds on the side-chain provide theoretical support for the rapid self-healing ability of PU. Maximum stress of the synthesized PU can reach 3.4 ± 0.15 Mpa, and maximum elongation at break can reach 3200% ± 160%. Due to flexibility and re-constructability of side-chain hydrogen bonds, PU stress repair efficiency can reach 96.7%, and can be self-healing scratches rapidly and effectively at room temperature. The mechanical properties and self-healing properties of PU can be adjusted by the content of T-type chain extender. The PU is applied to the metal surface coating, which has excellent acid-base resistance, bond strength up to 2.9 ± 0.1 Mpa, and the ability to eliminate local damage on the coating surface quickly at room temperature.


Asunto(s)
Elastómeros , Poliuretanos , Enlace de Hidrógeno , Resistencia a la Tracción
3.
Inorg Chem ; 59(13): 9177-9187, 2020 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-32447953

RESUMEN

By taking advantage of the efficient Förster resonance energy transfer (FRET) between near-infrared (NIR)-responsive lanthanide-doped upconversion nanoparticles (UCNPs) and Fenton reagent ferrocenyl compounds (Fc), a series of Fc-UCNPs was designed by functionalizing NaYF4:Yb,Tm nanoparticles with Fc1-Fc5 via surface-coordination chemistry. Fc-UCNP-Lipo nanosystems were then constructed by encapsulating Fc-UCNP inside liposomes for efficient delivery. Fc-UCNP can effectively release ·OH via a NIR-promoted Fenton-like reaction. In vitro and in vivo studies of Fc1-UCNP-Lipo confirmed the preferential accumulation in a tumor site followed by an enhanced uptake of cancer cells. After cellular internalization, the released Fc1-UCNP can effectively promote ·OH generation for tumor growth suppression. Such a Fc1-UCNP-Lipo nanosystem exhibits advantages such as easy fabrication, low drug dosage, and no ferrous ion release.


Asunto(s)
Antineoplásicos/uso terapéutico , Compuestos Ferrosos/uso terapéutico , Nanopartículas del Metal/uso terapéutico , Metalocenos/uso terapéutico , Neoplasias/tratamiento farmacológico , Animales , Antineoplásicos/síntesis química , Antineoplásicos/efectos de la radiación , Línea Celular Tumoral , Portadores de Fármacos/química , Femenino , Compuestos Ferrosos/química , Compuestos Ferrosos/efectos de la radiación , Humanos , Rayos Infrarrojos , Liposomas/química , Nanopartículas del Metal/química , Nanopartículas del Metal/efectos de la radiación , Metalocenos/química , Metalocenos/efectos de la radiación , Ratones Endogámicos BALB C , Neoplasias/patología , Terbio/química , Terbio/efectos de la radiación , Ensayos Antitumor por Modelo de Xenoinjerto , Itrio/química , Itrio/efectos de la radiación
4.
J Reconstr Microsurg ; 36(6): 397-402, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32040964

RESUMEN

BACKGROUND: Immunosuppression risks are a major concern with vascularized composite allotransplantation (VCA). As an emerging strategy, the antirejection role played by mesenchymal stem cells (MSCs) is receiving attention. However, the current literature reports are inconclusive regarding the robustness of the MSC monotherapy. Using a rat forelimb VCA model, this study tested the robustness of the immunomodulation efficacy of gingival-derived MSCs (GMSCs) and bone marrow-derived MSCs (BMMSCs). METHODS: Forelimbs were transplanted on pairs of major histocompatibility complex-incompatible rats (Wistar-Kyoto donor, Lewis [LEW] recipient). Twenty-four LEW rats were randomly divided into four groups, including control (no treatment) and three treatment groups: rapamycin (2 mg/kg/day for 28 days, postoperatively), BMMSC and GMSC, both of which received donor-derived stem cells administered intravenously on postoperative days (PODs) 0, 3, 7, and 14. Rejection was considered as 80% skin necrosis of the allograft. Microcomputed tomography (µCT) was performed to evaluate healing at osteosynthesis site. On POD 14, limbs from each group underwent histological analysis and rejection grading using the Banff system. RESULTS: Both BMMSC (15.0 days) and GMSC (14.7 days) treatment failed to prolong VCA survival in comparison with the control group (13.8 days; p > 0.050), while the rapamycin significantly delayed acute VCA rejection (24.5 days; p = 0.003). Micro-CT imaging revealed no gross visual difference across all groups. Histology revealed that the control group was most severely affected (grades III and IV) followed by MSC (grade II) and rapamycin (grade I). CONCLUSION: MSC monotherapy, both BMMSC and GMSC, did not inhibit rejection in our VCA model. Skin immunogenicity is an important issue in promoting rejection, and a concomitant immunosuppression regimen should be considered to prolong allograft survival.


Asunto(s)
Células Madre Mesenquimatosas , Alotrasplante Compuesto Vascularizado , Animales , Rechazo de Injerto , Supervivencia de Injerto , Miembro Posterior , Ratas , Ratas Endogámicas Lew , Ratas Endogámicas WKY , Microtomografía por Rayos X
5.
Appl Microbiol Biotechnol ; 100(16): 7249-61, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27102128

RESUMEN

Bioremediation of areas co-contaminated with metals and polycyclic aromatic hydrocarbons (PAHs) by mushrooms has attracted considerable attention in recent years. In this study, Pleurotus eryngii was introduced for the removal of Mn and phenanthrene (Phe) from potato liquid medium (PDL) simultaneously. Effects of Tween 80 and saponin on P. eryngii growth together with Mn uptake as well as Phe removal were investigated. Although pollutants had a negative effect on mycelial morphology and growth, P. eryngii could still tolerate and remove Mn and Phe. Tween 80 increased removal of Mn and Phe through increase of P. eryngii growth, Phe solubility, pollutants bioavailability, and specific surface area of mycelium pellets, moreover, the activities of manganese peroxidase (MnP) and laccase, which played an important role on PAHs biodegradation. The maximal removal of Mn and Phe was achieved (92.17 and 93.85 % after 15 days incubation, respectively) with 0.6 g L(-1) Tween 80. Treatments with saponin markedly inhibited P. eryngii growth (50.17-66.32 % lower relative to control) due to its fungistatic activity. Nevertheless, saponin could slightly enhance Phe removal through increasing solubility of Phe, and Phe removal rate varied from 80.53 to 87.06 % in saponin treatments. Joint stress of Mn and Phe induced a strong antioxidative response, and superoxide dismutase (SOD) activity decreased in surfactants-treated mycelium compared with control. Generally, Tween 80 was more suitable for strengthening mycoremediation by P. eryngii than saponin, and could be a promising alternative for the remediation of heavy metals and PAHs co-contaminated sites by mushrooms.


Asunto(s)
Manganeso/metabolismo , Fenantrenos/metabolismo , Pleurotus/metabolismo , Hidrocarburos Policíclicos Aromáticos/metabolismo , Polisorbatos/metabolismo , Saponinas/metabolismo , Contaminantes del Suelo/metabolismo , Biodegradación Ambiental , Lacasa/metabolismo , Microscopía Electrónica de Rastreo , Micelio/metabolismo , Tensoactivos/metabolismo
6.
Sci Total Environ ; 912: 169182, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38092201

RESUMEN

During the COVID-19 pandemic, a significant increased number of masks were used and improperly disposed of. For example, the global monthly consumption of approximately 129 billion masks. Masks, composed of fibrous materials, can readily release microplastics, which may threaten various soil ecosystem components such as plants, animals, microbes, and soil properties. However, the specific effects of mask-derived microplastics on these components remain largely unexplored. Here, we investigated the effects of mask-derived microplastics (grouped by different concentrations: 0, 0.25, 0.5, and 1 % w/w) on soil physicochemical properties, microbial communities, growth performance of lettuce (Lactuca sativa L. var. ramosa Hort.) and earthworm (Eisenia fetida) under laboratory conditions for 80 days. Our findings suggest that mask-derived microplastics reduced soil bulk density while increasing the mean weight diameter of soil aggregates and modifying nutrient levels, including organic matter, potassium, nitrogen, and phosphorus. An increase in the abundance of denitrification bacteria (Rhodanobacteraceae) was also observed. Mask-derived microplastics were found to reduce lettuce germination, and a hormesis effect of low-concentration stimulation and high-concentration inhibition was observed on biomass, chlorophyll, and root activity. While the mortality of earthworms was not significantly affected by the mask-derived microplastics, but their growth was inhibited. Collectively, our results indicate that mask-derived microplastics can substantially impact soil properties, plant growth, and earthworm health, with potential implications for soil ecosystem functionality.


Asunto(s)
Oligoquetos , Contaminantes del Suelo , Animales , Humanos , Microplásticos , Suelo/química , Ecosistema , Plásticos/toxicidad , Pandemias , Contaminantes del Suelo/análisis , Oligoquetos/fisiología
7.
J Oral Maxillofac Surg ; 69(4): 1103-7, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20619950

RESUMEN

PURPOSE: Autologous microvascular submandibular gland (SMG) transfer is an effective treatment for severe keratoconjunctivitis sicca (KCS). However, epiphora (excessive tear secretion) may occur after the successful transfer of whole submandibular gland because tear secretion level is closely related to the size of the transferred gland. The aim of this study was to investigate the microanatomy of SMG to explore the possibility of partial SMG transfer to prevent postoperative epiphora. MATERIALS AND METHODS: Sixty intact and histologically normal human SMGs from patients with benign tumor of the mandible who underwent vascularized mandibular reconstruction and removal of the SMG for anastomosis of the blood vessels were included in the study. SMGs were perfused with methacrylate to form resin casts of blood vessels and ducts. The length and diameter of the blood vessels and ducts in the casts were measured using a sliding caliper. The numbers of lobules, distribution of arteries, veins, and ducts, as well as the relationship among them, were analyzed. RESULTS: The resin cast of the gland showed a treelike structure, with the vessels gradually dividing into multiple branches. The arteries, veins, and ducts run in parallel and were roughly divided into 3 levels: from the stem extending into the main branches (level I), into the narrower secondary branches (level II), and then the secondary branches subsequently divided into terminal branches (level III). The structures of the blood vessels and ducts were similar at each level in the lobules. In the vein casts, communicating vessels were found between the anterior facial vein and the concomitant vein of the facial artery. CONCLUSION: The characteristic treelike structure of the SMG vascular and ductal system may provide useful information for partial gland transfers.


Asunto(s)
Microvasos/anatomía & histología , Conductos Salivales/anatomía & histología , Glándula Submandibular/anatomía & histología , Adulto , Arterias/anatomía & histología , Arteriolas/anatomía & histología , Femenino , Humanos , Queratoconjuntivitis Seca/cirugía , Enfermedades del Aparato Lagrimal/prevención & control , Masculino , Complicaciones Posoperatorias/prevención & control , Glándula Submandibular/irrigación sanguínea , Glándula Submandibular/trasplante , Venas/anatomía & histología , Vénulas/anatomía & histología
8.
Transl Pediatr ; 10(12): 3159-3165, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35070829

RESUMEN

BACKGROUND: Dexmedetomidine (D) and esketamine (K) are used for the sedation of pediatric dental surgery. This study was designed to compare the effect of intranasal D and K in producing moderate sedation for uncooperative pediatric dental patients. METHODS: This prospective single-center cohort study was conducted at the Maternal and Child Health Hospital of Hubei Province after approval of the Medical Ethics Committee. One hundred and fifty American Society of Anesthesiologists (ASA) grade I and II patients aged 3-10 years who were uncooperative and could not be managed by conventional behavior management techniques were included in this study. Patients were classified into four groups. Group K was administered with esketamine (0.5 mg/kg), and group D was given D1 (1 µg/kg), D2 (1.5 µg/kg), or D3 (2.0 µg/kg) intranasally. The outcome measurements included the sedation level, changes in vital signs, sedation onset and recovery times, analgesia, behavior, and overall success. RESULTS: The sedation onset time was significantly shorter for K and D3 compared with D1 and D2. The recovery time was fastest in group D1. The overall success rate was highest in group D3, followed by the D2, D1, and K groups; however, the difference between them was not significant. The intra-and postoperative pain scores in the D3 and K groups were significantly lower than those in the D1 group. CONCLUSIONS: Intranasal D and K are effective in producing moderate sedation for uncooperative pediatric dental patients.

9.
J Oral Maxillofac Surg ; 68(3): 606-10, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20171479

RESUMEN

PURPOSE: To investigate the relationship between the ducts of the submandibular gland (SMG) and sublingual gland (SLG) and discuss its clinical application relating to SMG radiologic examinations and transfer. MATERIALS AND METHODS: The microanatomy of the SMG and SLG was investigated by use of 30 adult cadavers through anatomic dissection by use of a microscope. The relationship between the SMG and SLG ducts was observed and recorded during operations of microvascular autologous SMG transfer in 63 cases of severe keratoconjunctivitis sicca. RESULTS: There were 3 patterns of SLG and SMG duct anatomic variation: 1) The SMG and SLG have their own respective ducts that secrete separately at the orifices of the ducts in the floor of the mouth. 2) The SLG has a major duct that joins the duct of the SMG. 3) The SLG only has many fine ducts (7-15) that secrete in the floor of the mouth. CONCLUSIONS: The anatomy of the ducts of the SMG and SLG is quite complicated. More attention should be paid to the anatomy of the ducts during surgery or imaging procedures related to the SMG.


Asunto(s)
Queratoconjuntivitis Seca/cirugía , Conductos Salivales/anatomía & histología , Glándula Sublingual/anatomía & histología , Glándula Submandibular/anatomía & histología , Adolescente , Adulto , Cadáver , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Procedimientos Quirúrgicos Orales/métodos , Conductos Salivales/trasplante , Glándula Submandibular/trasplante , Adulto Joven
10.
J Control Release ; 328: 210-221, 2020 12 10.
Artículo en Inglés | MEDLINE | ID: mdl-32860927

RESUMEN

To date, many clinical trials have been carried out with neoantigen-specific mRNA vaccines, and positive results have been achieved. However, further improvements in the efficiency of the intracellular delivery of mRNA and the production of a stronger immune response are still worth studying. In this study, we used the cholesterol-modified cationic peptide DP7 (VQWRIRVAVIRK), which was developed in our previous study, with a transmembrane structure and immunoadjuvant function to modify DOTAP liposomes to create a common mRNA delivery system. This system was intended to improve the efficiency of the delivery of mRNA encoding individualized neoantigens to dendritic cells (DCs) and enhance the activation of DCs. The system serves dual functions as a carrier and as an immunoadjuvant. As a carrier of mRNA, DP7-C-modified DOTAP liposomes (DOTAP/DP7-C) could transfer mRNA efficiently into different type of DCs in vitro. As an immunoadjuvant, DOTAP/DP7-C liposomes were shown to be more efficacious in stimulating DC maturation, CD103+ DC (contributing to antigen presentation) production and proinflammatory cytokine secretion than DOTAP liposomes both in vitro and in vivo. In animal studies, the subcutaneous administration of DOTAP/DP7-C/LL2 neoantigen-encoding mRNA complexes significantly inhibited the growth of LL2 in situ and the growth of subcutaneous tumors and stimulated the production of antigen-specific lymphocyte reactions, which were superior to the DOTAP/LL2 neoantigen-encoding mRNA complex group. In conclusion, DOTAP/DP7-C liposomes may serve as a potential universal mRNA delivery system, providing a simple method to increase the efficiency of intracellular mRNA delivery and the immunostimulatory activity of DCs.


Asunto(s)
Liposomas , Vacunas , Animales , Antígenos , Células Dendríticas , Ácidos Grasos Monoinsaturados , Inmunidad , Compuestos de Amonio Cuaternario , ARN Mensajero
11.
J Hazard Mater ; 380: 120893, 2019 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-31325691

RESUMEN

Selective enriching low content of radionuclides from radioactive wastewater is a critical issue for environmentally benign utilization of nuclear power. Inspired by the tolerance mechanism of plants to radionuclides, we developed a pH-triggered ultraselective coordinative adsorption (CA) membrane. The as-prepared CA membrane featured the advantages of both coordinative adsorption and membrane separation, including ultrahigh selectivity coefficient of 1242, large capacity (80 L m-2) and short mass transfer distance. The adsorption isotherms of Th4+ on the CA membrane were well described by the Freundlich model (R2 > 0.99), and the adsorption kinetics have a good fitting by using the pseudo-second-order kinetic model (R2 > 0.99). In a continuous separation under gravity, the CA membrane was able to selectively enrich the low content of Th4+ (0.05 mmol L-1) in the presence of 700 folds (35 mmol L-1) of co-existing ions (Na+, Mg2+, K+, Ca2+, Sr2+, Cs+ and Ba2+). The exceptional extraction efficiency to Th4+ was 100%, superior to that (3.7%) of all co-existing ions. Notably, the Th4+ enriched on the CA membrane was facilely eluted by diluted HNO3 (0.1 mol L-1). The Th4+ in the eluents was enriched by up to 54 folds. The eluted CA membrane was further reused for selective enrichment of Th4+, which showed no obvious loss of selectivity and enrichment capability. Our strategy might open up a new strategy for realizing ultraselective and recyclable enrichment of low content of irradiation contaminants from wastewater.


Asunto(s)
Adaptación Fisiológica , Fenómenos Fisiológicos de las Plantas , Torio/metabolismo , Membranas Artificiales , Taninos/metabolismo , Torio/análisis
12.
Biomater Sci ; 5(4): 669-677, 2017 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-28154853

RESUMEN

Stimuli-responsive nanocarriers have been limited for bench-to-bedside translation mainly because the stimuli sensitivity and responsive rate are not high enough to ensure sufficient drug concentration at the target sites for superior therapeutic benefits. Herein, we reported an enhanced bioreduction-responsive and biodegradable nanocarrier based on the amphiphilic poly(ester urethane) copolymers (PAUR-SeSe) bearing multiple diselenide groups on the backbone. The copolymer could spontaneously self-assemble into stable micelles in aqueous medium with an average diameter of 68 nm, which could be rapidly disassembled in a reductive environment as a result of the reduction-triggered cleavage of diselenide groups. Furthermore, the PAUR-SeSe micelles showed an enhanced drug release profile and cellular uptake compared with the disulfide-containing analogue (PAUR-SS). CCK8 assays revealed that the antitumor activity of DOX-loaded PAUR-SeSe micelles was much higher than that of DOX-loaded PAUR-SS micelles. Besides, the blank micelles and degradation products were nontoxic up to a tested concentration of 50 µg mL-1. Therefore, the enhanced therapeutic efficacy and good biocompatibility demonstrated that this drug nanocarrier had great potential for smart antitumor drug delivery applications.


Asunto(s)
Antibióticos Antineoplásicos/administración & dosificación , Preparaciones de Acción Retardada/química , Doxorrubicina/administración & dosificación , Micelas , Poliésteres/química , Poliuretanos/química , Antibióticos Antineoplásicos/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Doxorrubicina/farmacología , Liberación de Fármacos , Humanos , Oxidación-Reducción
13.
J Biomater Sci Polym Ed ; 28(5): 459-469, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28105891

RESUMEN

A rapid prototyping technology, formed by three-dimensional (3-D) printing and then crosslinked by spraying Ca2+ solution, is developed to fabricate a sodium alginate (SA) hydrogel scaffold. The porosity, swelling ratio, and compression modulus of the scaffold are investigated. A friction mechanism is developed by studying the reproducible friction behavior. Our results show that the scaffold can have 3-D structure with a porosity of 52%. The degree of swelling of the SA hydrogel scaffold is 8.5, which is nearly the same as bulk SA hydrogel. SA hydrogel exhibits better compressive resilience than bulk hydrogel despite its lower compressive modulus compared to bulk hydrogel. The SA hydrogel scaffold exhibits a higher frictional force at low sliding velocity (10-6 to 10-3 m/s) compared to bulk SA hydrogel, and they are equal at high sliding velocity (10-2 to 1 m/s). For a small pressure (0.3 kPa), the SA hydrogel scaffold shows good friction reproducibility. In contrast, bulk SA hydrogel shows poor reproducibility with respect to friction behavior. The differences in friction behaviors between the SA hydrogel scaffold and bulk SA hydrogel are related to the structure of the scaffold, which can keep a stable hydrated lubrication layer.


Asunto(s)
Alginatos/química , Hidrogeles/química , Impresión Tridimensional , Andamios del Tejido/química , Materiales Biocompatibles , Carbonato de Calcio/química , Reactivos de Enlaces Cruzados/química , Fricción , Ácido Glucurónico/química , Ácidos Hexurónicos/química , Ensayo de Materiales , Fenómenos Mecánicos , Porosidad , Reproducibilidad de los Resultados , Soluciones , Ingeniería de Tejidos
14.
Bioresour Technol ; 216: 677-83, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27289059

RESUMEN

Syngas based co-digestion is not only more economically attractive than separate syngas methanation but also able to upgrade biogas and increase overall CH4 amount simultaneously. However, high H2 concentration in the syngas could inhibit syntrophic degradation of propionate, resulting in propionate accumulation and even failure of the co-digestion system. In an attempt to reduce propionate accumulation via enhancing both H2 interspecies transfer (HIT) and direct interspecies electron transfer (DIET) pathways, layered granule-based biofilms induced by conductive carbon felt particles (CCFP) was employed. The results showed that propionate accumulation was effectively reduced with influent COD load up to 7gL(-1)d(-1). Two types of granule-based biofilms, namely biofilm adhered to CCFP (B-CCFP) and granules formed by self-immobilization (B-SI) were formed in the reactor. Clostridium, Syntrophobacter, Methanospirillum were possibly involved in HIT and Clostridium, Geobacter, Anaerolineaceae, Methanosaeta in DIET, both of which might be responsible for the high-rate propionate degradation.


Asunto(s)
Biocombustibles , Biotecnología/métodos , Carbono , Hidrógeno , Propionatos/metabolismo , Anaerobiosis , Biopelículas , Análisis de la Demanda Biológica de Oxígeno , Reactores Biológicos/microbiología , Biotecnología/instrumentación , Fibra de Carbono , Clostridium/metabolismo , Transporte de Electrón , Geobacter/metabolismo , Metano/metabolismo , Consorcios Microbianos , Presión Parcial
15.
Mater Sci Eng C Mater Biol Appl ; 66: 92-99, 2016 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-27207042

RESUMEN

Drug-eluting stents with biodegradable polymers as reservoirs have shown great potential in the application of interventional therapy due to their capability of local drug delivery. Herein, poly(l-lactide-co-ε-caprolactone) (PLCL) with three different compositions as carriers for ciprofloxacin lactate (CIP) was coated on ureteral stents by the dipping method. To simulate a body environment, degradation behavior of PLCL as both the bulk film and the stent coating was evaluated in artificial urine (AU, pH6.20) respectively at 37°C for 120days by tracing their weight/Mn loss, water absorption and surface morphologies. Furthermore, the release profile of the eluting drug CIP on each stent exhibited a three-stage pattern, which was greatly affected by the degradation behavior of PLCL except for the burst stage. Interestingly, the degradation results on both macroscopic and molecular level indicated that the release mechanism at stage I was mainly controlled by chain scission instead of the weight loss or morphological changes of the coatings. While for stage II, the release profile was dominated by erosion resulting from the hydrolysis reaction autocatalyzed by acidic degradation residues. In addition, ciprofloxacin-loaded coatings displayed a significant bacterial resistance against E. coli and S. aureus without obvious cytotoxicity to Human foreskin fibroblasts (HFFs). Our results suggested that PLCL copolymers with tunable degradation rate as carriers for ciprofloxacin lactate could be used as a promising long-term antibacterial coating for ureteral stents.


Asunto(s)
Antibacterianos/química , Ciprofloxacina/química , Portadores de Fármacos/química , Stents Liberadores de Fármacos , Antibacterianos/farmacología , Antibacterianos/orina , Línea Celular , Supervivencia Celular/efectos de los fármacos , Ciprofloxacina/farmacología , Ciprofloxacina/orina , Liberación de Fármacos , Escherichia coli/efectos de los fármacos , Humanos , Microscopía Electrónica de Rastreo , Poliésteres/química , Staphylococcus aureus/efectos de los fármacos
16.
Guang Pu Xue Yu Guang Pu Fen Xi ; 22(5): 767-9, 2002 Oct.
Artículo en Zh | MEDLINE | ID: mdl-12938425

RESUMEN

In this paper, a series of new polymers with grafted amino acids were synthesized. The purpose of the research is to develop a kind of polymer drugs with grafted amino acids for the treatment of some patients. The preparations of polyvinyl alcohol and amino acid were described by using inorganic acid as catalyst. The reaction methods were investigated in order to find the optimal conditions for the highest yield and purity. The copolymers were analysed and characterized by IR and 1HNMR. The result indicated that the reaction products were what we needed and the yield of the polymer of polyvinyl alcohol and glycine was higher than that of polyvinyl alcohol and alanine.


Asunto(s)
Alanina/química , Glicina/química , Polímeros/química , Alcohol Polivinílico/química , Aminoácidos/química , Catálisis , Espectroscopía de Resonancia Magnética/métodos , Polímeros/síntesis química , Espectrofotometría Infrarroja/métodos
17.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 41(12): 759-61, 2006 Dec.
Artículo en Zh | MEDLINE | ID: mdl-17349202

RESUMEN

OBJECTIVE: To study the monomolecular coverage of the silane coupling agent gamma-methacryloxypropyltrimethoxysilane (gamma-MPS) on the barium glass filler surface. METHODS: Kubelka-Munk (K-M) function values of the isolated OH-groups on the barium glass filler surface, which were based on the change of gamma-MPS concentrations, were measured using the quantitative analysis of the diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. When all of the isolated OH-groups on the filler surface disappeared (where the K-M function values was zero), the monomolecular coverage of the gamma-MPS molecules on the filler surface was indicated by the linear regression analysis. RESULTS: The relationship tallied with negative linear correlation between the K-M function values of the isolated OH-groups on the barium glass surface and the concentrations of gamma-MPS. Each gamma-MPS molecule occupied 0.21 nm(2) when the monomolecular coverage was formed on the barium glass surface. CONCLUSIONS: The result of this study indicated the optimal amount of silane coupling agent on silanated barium glass filler during the production of resin composite.


Asunto(s)
Compuestos de Bario/química , Resinas Compuestas/química , Metacrilatos/química , Silanos/química , Dióxido de Silicio/química , Materiales Dentales/química
18.
J Org Chem ; 69(25): 8609-17, 2004 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-15575736

RESUMEN

The chemistry between CO(2) and primary amines was used to construct novel types of supramolecular polymers and networks. Fluorescent self-assembling gel 2 was prepared, which employs both hydrogen bonding and dynamic, thermally reversible carbamate bonds. As precursors, biscalixarenes 1, 3, 4, 6, and 7 were synthesized, which strongly aggregate (K(D) > or = 10(6) M(-1) per capsule) in apolar solution with the formation of linear self-assembling polymers. Polymer 1n possesses CO(2)-philic primary amino groups on the periphery. CO(2) rapidly reacts with chains 1n in apolar solvents and cross-links them with the formation of multiple carbamate salt bridges. Three-dimensional polymeric network 2 was characterized by (13)C NMR spectroscopy and SEM. Addition of competitive solvent breaks hydrogen bonding in 2 but does not influence the carbamate linkers. Carbamate salt 9 was obtained. On the other hand, thermal release of CO(2) from 2 and 9 was easily accomplished (1 h, 100 degrees C) with retaining the hydrogen-bonding capsules. Thus, three-dimensional polymeric networks 2 were transformed back to linear polymeric chains 1n without their breakup. Multiple pyrene fluorophores, attached on the periphery of 2, cause strong fluorescence of the gel with benzene. When approximately 5% nitrobenzene was gelated together with benzene, fluorescence strongly decreases due to the energy transfer from the pyrene donors in gel 2 to trapped nitrobenzene molecules. This opens a way to switchable fluorescent materials.


Asunto(s)
Calixarenos/síntesis química , Dióxido de Carbono/química , Polímeros/síntesis química , Aminas/química , Calixarenos/química , Fluorescencia , Geles/síntesis química , Enlace de Hidrógeno , Sustancias Macromoleculares , Conformación Molecular , Polímeros/química
19.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 38(3): 203-5, 2003 May.
Artículo en Zh | MEDLINE | ID: mdl-12887799

RESUMEN

OBJECTIVES: To investigate the effect of particle size distribution (PSD) of dental poly (methyl methacrylate) (PMMA) beads on the microstructure of denture. METHODS: It was compared and analyzed that the porosity of three groups of spherical specimens which were made of PMMA beads with different PSD at proper polymer/monomer ratios. And the final microstructure of each group was investigated using Digital High Definition Microscope. RESULTS: With proper polymer/monomer ratio increasing, the occurrence of porosity tended to decrease. The final microstructure of denture varied with PSD of PMMA beads. CONCLUSION: By means of optimizing PSD of beads, the microstructure of denture could be improved, and the occurrence of porosity could be reduced.


Asunto(s)
Dentaduras , Polimetil Metacrilato/química , Materiales Dentales/química , Tamaño de la Partícula
20.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 38(6): 461-3, 2003 Nov.
Artículo en Zh | MEDLINE | ID: mdl-14703486

RESUMEN

OBJECTIVE: To determine the rheological properties of the photo-polymerized composite resin reinforced with retentive filler (RF) and its rheological difference with normal filler (NF) composite resin. METHODS: Rheological properties of the composite resins, such as viscosity, shear stress and creep compliance, were measured with dynamic stress rheometer at room temperature (25 degrees C). RESULTS: The viscosity of the composite resin reinforced with RF is higher than that of NF composite resin (P < 0.01); at the beginning, the viscosity of the former has little change with the rising of shear stress and the latter decreases, then the viscosities of the two composite resins increase with the rising of shear stress as soon as over 203.18 Pa of shear stress; the creep compliance of the composite resin reinforced with RF is significant smaller than that of NF composite resin (P < 0.01). CONCLUSIONS: The rheological properties of the two composite resins have significant difference, so they have different clinical using properties.


Asunto(s)
Resinas Compuestas/química , Restauración Dental Permanente , Viscosidad
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