Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 25
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Environ Sci Technol ; 54(11): 6530-6539, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32369699

RESUMO

Microplastics in the air have gradually attracted our attention in recent years; however, temporal and spatial trends of microplastics in indoor air are rarely discussed. In the present study, we tracked microplastic fallout in a dormitory, an office, and a corridor on both workdays and weekends for three months. In addition, an air conditioner was used to understand airflow influence on microplastic resuspension in the dorm. Among the three sampling sites, the highest average microplastic abundance appeared in the dormitory (9.9 × 103 MPs/m2/d), followed by the office (1.8 × 103 MPs/m2/d) and the corridor (1.5 × 103 MPs/m2/d). In the dormitory, the average MP abundance on weekends (1.4 × 104 MPs/m2/d) was approximately three times of that on weekdays (5.8 × 103 MPs/m2/d). In the office; however, the abundance on weekends (1.2 × 103 MPs/m2/d) was 50% of that on weekdays (2.4 × 103 MPs/m2/d). Microplastic fallout existed mostly in the form of fibers and showed similar polymer compositions to the textile products used in indoor environments. The airflow tests using an air conditioner suggested that airflow turbulence increased resuspension of microplastics. Taken together, we conclude that indoor environments are prone to serious microplastic pollution, but microplastic level varies greatly due to different characteristics of indoor setting. Our results also indicate that textile quantity is one of the main factors affecting microplastic abundance in indoor air, whereas air conditioner-induced airflow turbulence can cause microplastic migration in indoor environments.


Assuntos
Plásticos , Poluentes Químicos da Água , Monitoramento Ambiental , Poluição Ambiental/análise , Microplásticos , Poluentes Químicos da Água/análise
2.
Environ Sci Technol ; 53(17): 10188-10196, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31393116

RESUMO

Microplastics were demonstrated to be an environmental sink for hydrophobic organic pollutants, while they can also serve as a potential source of such pollutants. In this study, the sorption and release of bisphenol A in marine water were investigated through laboratory experiments. Sorption and desorption isotherms were developed, and the results reveal that sorption and desorption depend on the crystallinity, elasticity, and hydrophobicity of the polymer concerned. The adsorption and partition of bisphenol A can be quantified using a dual-mode model of the sorption mechanisms. Polyamide and polyurethane were found to exhibit the highest sorption capacity for bisphenol A, and it was almost irreversible, probably due to hydrogen bonding. Polyethylenes and polypropylene exhibited high and reversible sorption without noticeable desorption hysteresis. Glassy polystyrene, poly(vinyl chloride), poly(methyl methacrylate), and poly(ethylene terephthalate) exhibited low sorption capacity and only partial reversibility. Low-density polyethylene and polycarbonate microplastic particles were for the first time proved to be a persistent source releasing bisphenol A into aquatic environments. Salinity, pH, coexisting estrogens, and water chemistry influence the sorption/desorption behaviors to different degrees. Plastic particles can serve as transportation vectors for bisphenol A, which may constitute an ecological risk.


Assuntos
Plásticos , Poluentes Químicos da Água , Adsorção , Compostos Benzidrílicos , Fenóis
3.
J Hazard Mater ; 442: 130037, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36179620

RESUMO

Plastic additives widely existed in plastic mulching films, but their roles in microplastics (MPs) derived from these plastics as vectors of pollutants were not clear. This work clarified the role of plastic additives on the sorption-desorption behaviors of four arsenic species (arsenite (As(Ⅲ)), arsenate (As(Ⅴ)), roxarsone (ROX), and p-arsanilic acid (p-ASA)) on/from virgin polyethylene (V-PE), white PE mulching film (W-PE, with Si-containing additives), and black PE mulching film (B-PE, with CaCO3 and TiO2 additives) MPs. The maximum sorption amounts of arsenic species on V-PE (3.33-20.10 mg/kg) and W-PE MPs (4.78-21.93 mg/kg) had no significant difference, while those on B-PE (43.02-252.19 mg/kg) facilitated by its additives were up to one order of magnitude greater than V-PE or W-PE (p < 0.05). Desorption hysteresis index (HI) indicated the irreversible arsenic sorption on three PE MPs, especially for B-PE containing additives that can co-precipitate and complex with arsenicals. The effects of pH, humic substances, and coexisting anions on arsenic sorption by B-PE were more obvious than that by V-PE or W-PE MPs, attributing to electrostatic interaction enhanced by CaCO3 and TiO2 additives. This work provides theoretical basis for migration of arsenic species on MPs containing plastic additives and their potential environmental risk assessment.


Assuntos
Arsênio , Arsenicais , Arsenitos , Poluentes Ambientais , Roxarsona , Poluentes Químicos da Água , Microplásticos , Plásticos/química , Arseniatos , Polietileno/química , Substâncias Húmicas , Ácido Arsanílico , Adsorção , Poluentes Químicos da Água/química
4.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 37(3): 302-307, 2023 Mar 15.
Artigo em Zh | MEDLINE | ID: mdl-36940988

RESUMO

Objective: To prepare a new plastic bone filler material with adhesive carrier and matrix particles derived from human bone, and evaluate its safety and osteoinductive ability through animal tests. Methods: The human long bones donated voluntarily were prepared into decalcified bone matrix (DBM) by crushing, cleaning, and demineralization, and then the DBM was prepared into bone matrix gelatin (BMG) by warm bath method, and the BMG and DBM were mixed to prepare the experimental group's plastic bone filler material; DBM was used as control group. Fifteen healthy male thymus-free nude mice aged 6-9 weeks were used to prepare intermuscular space between gluteus medius and gluteus maximus muscles, and all of them were implanted with experimental group materials. The animals were sacrificed at 1, 4, and 6 weeks after operation, and the ectopic osteogenic effect was evaluated by HE staining. Eight 9-month-old Japanese large-ear rabbits were selected to prepare 6-mm-diameter defects at the condyles of both hind legs, and the left and right sides were filled with the materials of the experimental group and the control group respectively. The animals were sacrificed at 12 and 26 weeks after operation, and the effect of bone defect repair were evaluated by Micro-CT and HE staining. Results: In ectopic osteogenesis experiment, HE staining showed that a large number of chondrocytes could be observed at 1 week after operation, and obvious newly formed cartilage tissue could be observed at 4 and 6 weeks after operation. For the rabbit condyle bone filling experiment, HE staining showed that at 12 weeks after operation, part of the materials were absorbed, and new cartilage could be observed in both experimental and control groups; at 26 weeks after operation, the most of the materials were absorbed, and large amount of new bone could be observed in the 2 groups, while new bone unit structure could be observed in the experimental group. Micro-CT observation showed that the bone formation rate and area of the experimental group were better than those of the control group. The measurement of bone morphometric parameters showed that the parameters at 26 weeks after operation in both groups were significantly higher than those at 12 weeks after operation ( P<0.05). At 12 weeks after operation, the bone mineral density and bone volume fraction in the experimental group were significantly higher than those in the control group ( P<0.05), and there was no significant difference between the two groups in trabecular thickness ( P>0.05). At 26 weeks after operation, the bone mineral density of the experimental group was significantly higher than that of the control group ( P<0.05). There was no significant difference in bone volume fraction and trabecular thickness between the two groups ( P>0.05). Conclusion: The new plastic bone filler material is an excellent bone filler material with good biosafety and osteoinductive activity.


Assuntos
Plásticos , Engenharia Tecidual , Camundongos , Animais , Masculino , Humanos , Coelhos , Criança , Engenharia Tecidual/métodos , Camundongos Nus , Osso e Ossos , Cartilagem , Osteogênese , Gelatina
5.
J Hazard Mater ; 455: 131552, 2023 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-37207479

RESUMO

The impacts of microplastics (MPs) prevalent in soil on the transport of pollutants were urged to be addressed, which has important implications for ecological risk assessment. Therefore, we investigated the influence of virgin/photo-aged biodegradable polylactic acid (PLA) and non-biodegradable black polyethylene (BPE) mulching films MPs on arsenic (As) transport behaviors in agricultural soil. Results showed that both virgin PLA (VPLA) and aged PLA (APLA) enhanced the adsorption of As(Ⅲ) (9.5%, 13.3%) and As(Ⅴ) (22.0%, 6.8%) due to the formation of abundant H-bonds. Conversely, virgin BPE (VBPE) reduced the adsorption of As(Ⅲ) (11.0%) and As(Ⅴ) (7.4%) in soil owing to the "dilution effect", while aged BPE (ABPE) improved arsenic adsorption amount to the level of pure soil due to newly generated O-containing functional groups being feasible to form H-bonds with arsenic. Site energy distribution analysis indicated that the dominant adsorption mechanism of arsenic, chemisorption, was not impacted by MPs. The occurrence of biodegradable VPLA/APLA MPs rather than non-biodegradable VBPE/ABPE MPs resulted in an increased risk of soil accumulating As(Ⅲ) (moderate) and As(Ⅴ) (considerable). This work uncovers the role of biodegradable/non-biodegradable mulching film MPs in arsenic migration and potential risks in the soil ecosystem, depending on the types and aging of MPs.


Assuntos
Arsênio , Poluentes do Solo , Microplásticos/química , Solo/química , Plásticos/química , Arsênio/análise , Ecossistema , Poluentes do Solo/análise , Poliésteres , Polietileno/química
6.
J Microencapsul ; 29(1): 21-9, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22034954

RESUMO

Coenzyme Q(10) (CoQ(10)) proliposomes were prepared using the supercritical anti-solvent (SAS) technique to encapsulate CoQ(10). The mixture of cholesterol and soya bean phosphatidylcholine (PC) was chosen as wall materials. The effects of operation conditions (temperature, pressure and components) on the recovery of CoQ(10) and the CoQ(10) loading in CoQ(10) proliposomes were studied. At the optimum conditions of pressure of 8.0 MPa, temperature of 35°C, the weight ratio of 1/10 between CoQ(10) and PC, and the weight ratio of 1/3 between cholesterol and PC, the CoQ(10) loading reached 8.92%. CoQ(10) liposomes were obtained by hydrating CoQ(10) proliposomes and the entrapment efficiency of CoQ(10) reached 82.28%. The morphologies of CoQ(10) proliposomes were characterized by scanning electron microscope, and their solid states were characterized by X-ray diffractometer. The structures of CoQ(10) liposomes were characterized by transmission electron microscope. The particle size distribution of CoQ(10) liposomes was determined by dynamic light scattering instrument. The results indicate that CoQ(10) liposomes with particle sizes about 50 nm can be easily obtained from hydrating CoQ(10) proliposomes prepared by SAS technique.


Assuntos
Lipossomos , Solventes/química , Ubiquinona/análogos & derivados , Cromatografia Líquida de Alta Pressão , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Temperatura , Ubiquinona/química , Difração de Raios X
7.
Int J Mol Sci ; 13(5): 6454-6468, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22754377

RESUMO

In this study, solution enhanced dispersion by supercritical fluids (SEDS) technique was applied for the preparation of 5-aminosalicylic acid (5-ASA) loaded Eudragit S100 (EU S100) nanoparticles. The effects of various process variables including pressure, temperature, 5-ASA concentration and solution flow rate on morphology, particle size, 5-ASA loading and entrapment efficiency of nanoparticles were investigated. Under the appropriate conditions, drug-loaded nanoparticles exhibited a spherical shape and small particle size with narrow particle size distribution. In addition, the nanoparticles prepared were characterized by X-ray diffraction, Differential scanning calorimetry and Fourier transform infrared spectroscopy analyses. The results showed that 5-ASA was imbedded into EU S100 in an amorphous state after SEDS processing and the SEDS process did not induce degradation of 5-ASA.


Assuntos
Resinas Acrílicas/química , Mesalamina/síntese química , Nanopartículas/química , Química Farmacêutica , Tamanho da Partícula , Propriedades de Superfície
8.
Water Res ; 195: 116956, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33676178

RESUMO

Due to the hydrophobicity and large specific surface area microplastics (MPs) have become the vector for the migration of environmental organic pollutants. Environmental aging process affects the physiochemical structure of MPs and their corresponding environmental behaviors, in which the effect of bisphenol A (BPA) binding mode within plastic matrix on aging behaviors of MPs is not reported. In this work, the structural properties and BPA sorption behaviors of low density polyethylene (LDPE) MPs with BPA additives and polycarbonate (PC) MPs with BPA monomers exposed to three types of artificial accelerated aging processes including UV/H2O, UV/H2O2, and UV/Cl2 systems were comparatively investigated. Virgin LDPE and PC exhibited obvious leakage of BPA additives or monomers. Aged LDPE had stronger sorption ability towards BPA in water environment with no observed leakage of BPA additives. While, aged PC had extremely high leakage of BPA monomers, which is similar to virgin PCs and was proved to be a persistent source of BPA release. The BPA sorption on aged LDPE or leaching from aged PC was influenced by aging processes, water pH, salinity, co-existing estradiol (E2), and water sources. This study reveals the potential ecological and environmental risks of MPs containing toxic additives/monomers during aging processes from a new perspective.


Assuntos
Microplásticos , Poluentes Químicos da Água , Adsorção , Compostos Benzidrílicos , Peróxido de Hidrogênio , Fenóis , Plásticos , Água , Poluentes Químicos da Água/análise
9.
Chemosphere ; 226: 726-735, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30959457

RESUMO

Microplastics (MPs) have been regarded as a vector for contaminants and greatly affect the migration and fate of hydrophobic organic compounds (HOCs) in marine water. In this study, the sorption behavior of 17ß-estradiol (E2) on MPs was investigated in marine water system. The sorption capacity of E2 varied greatly with the chemical structures of MPs. The adsorption or partition contribution of E2 sorption on MPs was well quantified with adsorption-partition dual-mode model mechanism. The hydrophobic partition dominantly regulates the sorption of E2 due to the high crystallinity of MPs and high accessibility of amorphous domain of rubbery MPs. Smaller particle size benefits the sorption of E2 on same kind of MPs. The salinity and dissolved organic matter (DOM) have minor effect on E2 sorption by MPs in real marine water. The result shows that the MPs greatly influence the transportation of E2 and cause potential environmental risk to marine ecosystem.


Assuntos
Estradiol/química , Interações Hidrofóbicas e Hidrofílicas , Plásticos/química
10.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 33(11): 1452-1456, 2019 Nov 15.
Artigo em Zh | MEDLINE | ID: mdl-31650765

RESUMO

OBJECTIVE: To study the preservation effect of true bone ceramics (TBC) prepared by high-temperature calcination of bovine bone on alveolar ridge of canine extraction socket. METHODS: Six healthy Beagle dogs (aged 1.5-2 years) were selected to extract the second and fourth premolars of both mandibles and the second premolars of the maxilla. The left extraction socket was implanted with TBC as the experimental group, and the right side was implanted with the calcined bovine bone (CBB) as the control group, to observe the alveolar ridge preservation effect. Three dogs were euthanized after general observation at 1 and 6 months after operation respectively. After separating the maxilla and mandible, cone beam CT (CBCT) was performed to measure the average gray value of the graft site and the adjacent reference area (the area between the roots of the adjacent third premolar) and calculate the gray scale ratio between the bone graft site and the reference area. Histological observation was made on the bone graft site to evaluate the new bone formation. RESULTS: General observation showed that the wounds of both groups were basically healed at 2 weeks after operation, and the bone graft materials were not exposed. The wounds healed well at 1 and 6 months after operation without swelling. The results of CBCT showed that the residual material was found in both groups at 1 month after operation, and no significant residual material was found in both groups at 6 months after operation, and the alveolar ridge height of the bone graft area was not significantly reduced. There was no significant difference in the bone mineral density between the experimental group and the control group. The gray scale ratios of the experimental group at 1 month and 6 months after operation were 0.97±0.14 and 0.93±0.06, respectively, and were 0.99±0.16 and 0.94±0.05 in control group, showing no significant difference between the two groups ( t=-1.030, P=0.333; t=-0.770, P=0.466). HE staining observation showed that a large number of bone graft materials did not degrade and new bone formed around the grafts in both groups at 1 month after operation; the bone graft materials were absorbed and a large number of new bones were formed in both groups at 6 months after operation. CONCLUSION: TBC can maintain bone mineral density and have good osteoconductivity in the alveolar ridge site preservation experiment of dogs, and can be used for alveolar ridge site preservation.


Assuntos
Perda do Osso Alveolar , Processo Alveolar , Animais , Bovinos , Cerâmica , Cães , Extração Dentária , Alvéolo Dental
11.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 36(2): 194-198, 2018 Apr 01.
Artigo em Zh | MEDLINE | ID: mdl-29779283

RESUMO

OBJECTIVE: The prevalence rate, distribution, and reasons of immature permanent-tooth trauma in Xi'an were investigated and described, and a scientific basis was provided for the decision-making of health-administration departments. METHODS: Through cluster and simple random sampling survey, 4 013 pupils in schools from nine districts and four counties in Xi'an were sampled. All pupils and their parents were requested to complete a questionnaire. Oral examinations were conducted for children who had immature permanent teeth trauma. The number of trauma teeth and teeth were recorded. Survey data were analyzed statistically. RESULTS: The prevalence rate of immature permanent dental trauma was 10.5% in Xi'an. No significant differences were observed between districts and counties (P>0.05). The peak age of permanent dental trauma was at 7-9 years old, and the most was at 8 years old (31.5%). The first reason of trauma was falling down (50.9%), and the second reason was crash (36.0%). The most common trauma teeth were maxillary incisors (75.4%). CONCLUSIONS: The prevalence rate of immature permanent teeth trauma in Xi'an was in the middle of all international levels. Children, who are vulnerable to dental trauma at their age, should be provided with appropriate prevention measures to reduce the incidence of dental trauma.


Assuntos
Dentição Permanente , Traumatismos Dentários , Criança , China/epidemiologia , Humanos , Incisivo , Lactente , Prevalência , Inquéritos e Questionários , Traumatismos Dentários/epidemiologia
12.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 36(3): 308-313, 2018 Jun 01.
Artigo em Zh | MEDLINE | ID: mdl-29984934

RESUMO

OBJECTIVE: This study aims to investigate the clinical visiting and prognosis of schoolchildren in Xi'an after immature permanent tooth trauma and explore the prognostic factors associated with this type of trauma. METHODS: Through cluster and simple random sampling surveys, 4 013 pupils in schools from nine districts and four counties in Xi'an were sampled, respectively. All pupils and their parents were requested to complete a questionnaire, and children who had immature permanent tooth trauma answered a separate questionnaire and underwent oral examinations. The data of the survey were analyzed statistically. RESULTS: The amount of valid questionnaire was 3 641. Clinical visiting rate related to immature permanent tooth trauma of Xi'an schoolchildren was low (38.2%). Gender and trauma type were the factors related to clinical visiting for dental trauma concerns. The incidence of poor prognosis was 29.7%. The incidence of poor prognosis of patients with clinical visiting (35.4%) was higher than that of patients without clinical visiting (20.6%). CONCLUSIONS: Clinical visiting rate related to immature permanent tooth trauma in Xi'an schoolchildren is extremely low, and incidence of poor prognosis is high.


Assuntos
Dentição Permanente , Traumatismos Dentários , Criança , China/epidemiologia , Humanos , Prevalência , Prognóstico , Inquéritos e Questionários , Traumatismos Dentários/epidemiologia
13.
Dalton Trans ; 46(19): 6425-6432, 2017 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-28470270

RESUMO

1D Ag3PO4-NPs/Cu-NWs have been constructed to enhance visible-light-driven photocatalytic activity via biomimetic synthesis. Cu nanowires (NWs) were synthesized by a facile hydrothermal method. During the process of biomimetic synthesis, the porous PTFE film, which can mimic the transport process of cell membranes, plays an important role in controlling the transport speed of silver ions (Ag+) to decrease the reaction speed. Thus inhibition of the replacement reaction of Ag+/Cu and the uniform growth of Ag3PO4 nanoparticles (NPs) with a diameter of about 10 nm on Cu-NWs can be realized simultaneously. The diameter of Ag3PO4-NPs/Cu-NW is about 70 nm. Owing to the high electron transport of single crystal Cu-NWs, the free electrons in Ag3PO4 are transferred out to promote photogenerated electron-hole pair separation. The stability of Ag3PO4 NPs of the Ag3PO4-NPs/Cu-NWs was improved and the photodecomposition no longer occurred. Meanwhile, the band-gap of Ag3PO4 decreased to 2.07 eV after being coated on Cu-NWs and expanded the absorption scope of visible-light. In addition, the active species-trapping experiments indicated that the holes and ˙O2- play important roles in the photocatalytic reactions. The novel Ag3PO4-NPs/Cu-NWs were used for the degradation of ciprofloxacin (CPFX) for the first time and showed high photocatalytic degradation performance. After visible-light irradiation for 15 min, the degradation rates of CPFX with pure Ag3PO4 NPs and AC0.3 as catalysts were about 27% and 53%. In the end, the degradation efficiency of Ag3PO4-NPs/Cu-NWs was 6.07 times that of the pure Ag3PO4 NPs.


Assuntos
Antibacterianos/metabolismo , Materiais Biomiméticos/síntese química , Ciprofloxacina/metabolismo , Cobre/química , Fosfatos/química , Compostos de Prata/química , Animais , Materiais Biomiméticos/química , Catálise , Transporte de Elétrons , Saúde Ambiental , Humanos , Luz , Nanopartículas/química , Nanofios/química , Fotólise , Politetrafluoretileno/química , Semicondutores
14.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 31(10): 1250-1255, 2017 10 15.
Artigo em Zh | MEDLINE | ID: mdl-29806330

RESUMO

Objective: To investigate the biocompatibility of true bone ceramic (TBC) and provide experimental basis for clinic application. Methods: TBC was prepared from healthy adult bovine cancellous bone by deproteinization and high temperature calcinations. Mouse fibroblast cell line (L929 cells) were cultured with the leaching liquor of TBC in vitro, and the cytotoxicity was evaluated at 2nd, 4th, and 7th days. L929 cells were inoculated into the TBC and cultured for 4 days. The cell adhesion and proliferation on the surface of the TBC were observed by scanning electron microscopy, and evaluated the cell compatibility of TBC. Ten New Zealand white rabbits were divided into 2 groups, and drilled holes at the tibia of both hind limbs. TBC and hydroxyapatite (HA) were implanted into the left side (experimental group) and the right side (control group), respectively. And the biocompatibility of TBC was evaluated by general observation and histological observation at 4 and 26 weeks after implantation. Results: Cytotoxicity test showed that the cytotoxicity level of leaching liquor of TBC was grade 0-1. Cell compatibility experiments showed that the L929 cells adhered well on the surface of TBC and migrated into the pores. The implantation test in vivo showed that experimental group and control group both had mild or moderate inflammatory response at 4 weeks, and new bone formation occurred. At 26 weeks, there was no inflammatory reaction observed in both groups, and new bone formation was observed in varying degrees. Conclusion: TBC have good biocompatibility and can be used to repair bone defect in clinic.


Assuntos
Materiais Biocompatíveis , Próteses e Implantes , Animais , Osso e Ossos , Bovinos , Cerâmica , Durapatita , Camundongos , Coelhos
15.
Water Environ Res ; 78(4): 392-6, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16749307

RESUMO

This study was conducted to examine the feasibility of using a moving-bed-biofilm reactor with internal circulation through aeration for the treatment of municipal wastewater. The attached film was a mixed-microorganism consortium, which used composite-refined-diatomaceous earth as novel biomass carriers to form a diatomaceous-earth-moving-bed-biofilm-reactor (DEMBBR) process. The startup of laboratory-scale, continuous-flow reactor was successfully achieved without seeding activated sludge. The DEMBBR process removed chemical oxygen demand, total phosphorus, ammonium-nitrogen, and turbidity at the highest rate of 88.5, 83, 92.3, and 96.7%, respectively, with a hydraulic retention time of only 2.5 hours. The DEMBBR was less affected by interruption and adverse operation conditions than the conventional-activated-sludge reactor. Thus, the DEMBBR could be proposed to be a cost-effective, small-wastewater-treatment-process unit.


Assuntos
Reatores Biológicos/microbiologia , Terra de Diatomáceas/química , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Biofilmes/crescimento & desenvolvimento , Estudos de Viabilidade , Membranas Artificiais
16.
Ultrason Sonochem ; 32: 300-306, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27150774

RESUMO

Ultrasound-induced synthesis of chitosan-modified nano-scale graphene oxide (CS-NGO) hybrid nanosheets, which has great potential pharmaceutical applications, in supercritical CO2 without catalyst was presented for the first time. The preparation process does not require organic solvent and post-processing, and CO2 easily escapes from the product. The morphology and structure of the CS-NGO, characterized using scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis, confirms that it was combined via the amide linkage, and had excellent dispersibility and stability toward acidic and physiological aqueous solution, which implies that it could be used as a drug-carrier. The sonication power played a crucial role in inducing forming amidation, and the conversion rate increased with the sonication time. The mechanism of this reaction was explained.


Assuntos
Quitosana , Grafite , Ultrassom , Materiais Biocompatíveis , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Óxidos
17.
Cancer Chemother Pharmacol ; 77(2): 269-80, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26666650

RESUMO

Brain tumor lacks effective delivery system for treatment. Focused ultrasound (FUS) can reversibly open BBB without impacts on normal tissues. As a potential drug carrier, cationic liposomes (CLs) have the ability to passively accumulate in tumor tissues for their positive charge. In this study, FUS introduced doxorubicin-loaded cationic liposomes (DOX-CLs) were applied to improve the efficiency of glioma-targeted delivery. Doxorubicin-loaded CLs (DOX-CLs) and quantum dot-loaded cationic liposomes (QD-CLs) were prepared using extrusion technology, and their characterizations were evaluated. With the advantage of QDs in tracing images, the glioma-targeted accumulation of FUS + CLs was evaluated by fluorescence imaging and flow cytometer. Cell survival rate, tumor volume, animal survival time, and brain histology in C6 glioma model were investigated to evaluate the glioma-targeted delivery of FUS + DOX-CLs. DOX-CLs and QD-CLs had suitable nanoscale sizes and high entrapment efficiency. The combined strategy of FUS introduced CLs significantly increased the glioma-targeted accumulation for load drugs. FUS + DOX-CLs showed the strongest inhibition on glioma based on glioma cell in vitro and glioma model in vivo experiments. From MRI and histological analysis, FUS + DOX-CLs group strongly suppressed the glioma progression and extended the animal survival time to 81.2 days. Among all the DOX treatment groups, FUS + DOX-CLs group showed the best cell viability and highest level of tumor apoptosis and necrosis. Combining the advantages of BBB reversible opening by FUS and glioma-targeted binding by CLs, ultrasound introduced cationic liposomes could achieve glioma-targeted delivery, which might be developed as a potential strategy for future brain tumor therapy.


Assuntos
Barreira Hematoencefálica , Neoplasias Encefálicas , Doxorrubicina/análogos & derivados , Sistemas de Liberação de Medicamentos/métodos , Glioma , Ultrassonografia de Intervenção/métodos , Animais , Antibióticos Antineoplásicos/farmacologia , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/metabolismo , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Doxorrubicina/farmacologia , Portadores de Fármacos/farmacologia , Glioma/tratamento farmacológico , Glioma/patologia , Polietilenoglicóis/farmacologia , Ratos , Ratos Sprague-Dawley , Resultado do Tratamento , Carga Tumoral
18.
Int J Nanomedicine ; 10: 6633-44, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26543366

RESUMO

The aim of this investigation was to develop a procedure to improve the dissolution and bioavailability of silymarin (SM) by using bile salt-containing liposomes that were prepared by supercritical fluid technology (ie, solution-enhanced dispersion by supercritical fluids [SEDS]). The process for the preparation of SM-loaded liposomes containing a bile salt (SM-Lip-SEDS) was optimized using a central composite design of response surface methodology with the ratio of SM to phospholipids (w/w), flow rate of solution (mL/min), and pressure (MPa) as independent variables. Particle size, entrapment efficiency (EE), and drug loading (DL) were dependent variables for optimization of the process and formulation variables. The particle size, zeta potential, EE, and DL of the optimized SM-Lip-SEDS were 160.5 nm, -62.3 mV, 91.4%, and 4.73%, respectively. Two other methods to produce SM liposomes were compared to the SEDS method. The liposomes obtained by the SEDS method exhibited the highest EE and DL, smallest particle size, and best stability compared to liposomes produced by the thin-film dispersion and reversed-phase evaporation methods. Compared to the SM powder, SM-Lip-SEDS showed increased in vitro drug release. The in vivo AUC(0-t) of SM-Lip-SEDS was 4.8-fold higher than that of the SM powder. These results illustrate that liposomes containing a bile salt can be used to enhance the oral bioavailability of SM and that supercritical fluid technology is suitable for the preparation of liposomes.


Assuntos
Ácidos e Sais Biliares/química , Química Farmacêutica/métodos , Silimarina/química , Silimarina/farmacocinética , Administração Oral , Disponibilidade Biológica , Lipossomos , Tamanho da Partícula , Fosfolipídeos/química , Pressão , Silimarina/administração & dosagem
19.
Bioresour Technol ; 146: 355-362, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23948273

RESUMO

The aim of the current study is to investigate the feasibility of thermo-chemical conversion of rice husk in hot-compressed water via ultrasonic pretreatment to increase the bio-oil yield. The results show that ultrasonic pretreatment remarkably changes the structures of the rice husk, such as enhancing swelling and surface area, eroding lignin structure, and resulting in more exposure of the cellulose and hemicellulose. The highest bio-oil yield of 42.8% was obtained from the thermo-chemical conversion at 300 °C and 0 min of the residence time for the 1 h pretreated rice husk. GC-MS analysis indicates that the relative contents of phenols, 5-Hydroxymethylfurfural, and lactic acid are higher in bio-oils obtained from the pretreated rice husks than that from the raw rice husk.


Assuntos
Biocombustíveis , Furaldeído/análogos & derivados , Ácido Láctico/química , Lignina/química , Oryza/metabolismo , Ultrassom , Biomassa , Celulose/química , Furaldeído/química , Cromatografia Gasosa-Espectrometria de Massas , Temperatura Alta , Óleos , Polissacarídeos/química , Eliminação de Resíduos/métodos , Propriedades de Superfície , Temperatura , Fatores de Tempo , Água/química
20.
Pediatr Pulmonol ; 48(4): 381-9, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22911964

RESUMO

OBJECTIVE: To exam the relationship between snoring and morbidities of multiple systems in children. STUDY DESIGN: Children with snoring were enrolled and divided into primary snorer (PS) group and obstructive sleep apnea hypopnea syndrome (OSAHS) group based on polysomnography. The healthy children served as the control group. The growth parameters, maxillofacial malformations, blood chemistry, electrocardiogram, and echocardiogram were recorded and intelligence testing was performed in the enrolled children who were ≥6 years old. RESULTS: The weight and height were similar in the control group (n = 60) and the PS group (n = 63), but lower in the OSAHS group (n = 89; P < 0.001). Occurrence of adenoidal face and dental malocclusion in the OSAHS and the PS group was significantly higher than that in the control group (P < 0.001). Compared with the control group, the OSAHS group had a lower serum high-density lipoprotein cholesterol level, higher low-density lipoprotein cholesterol level; and a possible higher pulmonary artery pressure based on the echocardiogram (P < 0.001). All the above parameters in the PS group were similar to those in the control group. Full-scale IQ and performance IQ of the OSAHS group was lower (P < 0.001), attention deficits were significantly higher in the OSAHS group (P < 0.001), but were similar in the PS group when compared to the control group. CONCLUSIONS: OSAHS in children is associated with delayed growth, maxillofacial malformations, impaired cognitive functions, abnormalities in lipid metabolism, and changes in pulmonary artery pressures. PS children also have higher incidence of maxillofacial malformations but have a normal growth and normal cognitive functions.


Assuntos
Apneia Obstrutiva do Sono/complicações , Ronco/complicações , Estudos de Casos e Controles , Criança , Pré-Escolar , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/etiologia , Hipertensão Pulmonar Primária Familiar , Feminino , Transtornos do Crescimento/diagnóstico , Transtornos do Crescimento/etiologia , Humanos , Hipertensão Pulmonar/diagnóstico , Hipertensão Pulmonar/etiologia , Transtornos do Metabolismo dos Lipídeos/diagnóstico , Transtornos do Metabolismo dos Lipídeos/etiologia , Masculino , Anormalidades Maxilofaciais/complicações , Anormalidades Maxilofaciais/diagnóstico , Polissonografia , Apneia Obstrutiva do Sono/diagnóstico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA