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1.
J Ginseng Res ; 48(5): 449-453, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39263310

RESUMO

Korean Red Ginseng (KRG) has long been used not only as a food supplement but also as a treatment for various diseases. Ginseng originated in South Korea, which later spread to China and Japan, has a wide range of pharmacological activities including immune, endocrine, cardiovascular, and central nervous system effects. KRG is produced by repetitions of steaming and drying of ginseng to extend preservation. During this steaming process, the components of ginseng undergo physio-chemical changes forming a variety of potential active constituents including ginsenoside-Rg3, a unique compound in KRG. Pandemic Coronavirus disease 2019 (COVID-19), has affected both men and women differentially. In particular, women were more vulnerable to COVID-related distress which in turn could aggravate menopause-related disturbances. Complementary and alternative medicinal plants could have aided middle-aged women for several menopause-related symptoms during and post COVID-19 pandemic. This review aimed to explore the beneficial effects of KRG on menopausal symptoms and gynecological cancer.

2.
Bioact Mater ; 25: 360-373, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36879666

RESUMO

The tumor microenvironment consists of diverse, complex etiological factors. The matrix component of pancreatic ductal adenocarcinoma (PDAC) plays an important role not only in physical properties such as tissue rigidity but also in cancer progression and therapeutic responsiveness. Although significant efforts have been made to model desmoplastic PDAC, existing models could not fully recapitulate the etiology to mimic and understand the progression of PDAC. Here, two major components in desmoplastic pancreatic matrices, hyaluronic acid- and gelatin-based hydrogels, are engineered to provide matrices for tumor spheroids composed of PDAC and cancer-associated fibroblasts (CAF). Shape analysis profiles reveals that incorporating CAF contributes to a more compact tissue formation. Higher expression levels of markers associated with proliferation, epithelial to mesenchymal transition, mechanotransduction, and progression are observed for cancer-CAF spheroids cultured in hyper desmoplastic matrix-mimicking hydrogels, while the trend can be observed when those are cultured in desmoplastic matrix-mimicking hydrogels with the presence of transforming growth factor-ß1 (TGF-ß1). The proposed multicellular pancreatic tumor model, in combination with proper mechanical properties and TGF-ß1 supplement, makes strides in developing advanced pancreatic models for resembling and monitoring the progression of pancreatic tumors, which could be potentially applicable for realizing personalized medicine and drug testing applications.

3.
Biotechnol Bioprocess Eng ; 27(2): 163-170, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35530367

RESUMO

In this study, nanocomplexes composed of glycyrrhizic acid (GA) derived from the root of the licorice plant (Glycyrrhiza glabra) were formulated for the delivery of curcumin (CUR). Sonication of amphiphilic GA solution with hydrophobic CUR resulted in the production of nanosized complexes with a size of 164.8 ± 51.7 nm, which greatly enhanced the solubility of CUR in aqueous solution. A majority of the CURs were released from these GA/ CUR nanocomplexes within 12 h. GA/CUR nanocomplexes exhibited excellent intracellular uptake in human breast cancer cells (Michigan cancer foundation-7/multi-drug resistant cells), indicating enhanced anti-cancer effects compared to that of free CUR. In addition, GA/CUR nanocomplexes demonstrated high intracellular uptake into macrophages (RAW264.7 cells), consequently reducing the release of the pro-inflammatory cytokine tumor necrosis factor-α. Furthermore, GA/CUR nanocomplexes successfully reduced the levels of serum pro-inflammatory cytokines and splenomegaly in a rheumatoid arthritis model.

4.
Acta Biomater ; 141: 354-363, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35007784

RESUMO

In this study, combination therapy with the transforming growth factor-ß receptor I (TGFßRI) kinase inhibitor SD-208 and a toll-like receptor (TLR)-7/8 agonist resiquimod (R848) was examined along with serum-derived exosomes (EXOs) as versatile carriers. SD-208-encapsulated EXOs (SD-208/EXOs) and R848-encapsulated EXOs (R848/EXOs) were successfully prepared with a size of 87 ± 8 nm and 51 ± 4 nm, respectively, which were stable in aqueous solution at pH 7.4. SD-208/EXOs and R848/EXOs reduced the migration of cancer cells (B16F10 and PC-3) and triggered the release of proinflammatory cytokines from stimulated macrophages and dendritic cells, respectively. The fluorescent dye-labeled EXOs showed significantly improved penetration through the PC-3/fibroblast co-culture spheroids and enhanced accumulation in the B16F10 mouse tumor model compared with the free fluorescent dye. In addition, the combination therapy of R848/EXOs (R848 dose of 0.36 mg/kg) and SD-208/EXOs (SD-208 dose of 0.75 mg/kg) reduced tumor growth and improved survival rate at low doses in the B16F10 tumor xenograft model. Taken together, the combination therapy using the TGFßRI kinase inhibitor and TLR 7/8 agonist with EXOs may serve as a promising strategy to treat melanoma and prostate cancer. STATEMENT OF SIGNIFICANCE: Owing to the prevalence of several non-responding cancers that resist treatment, it is necessary to identify a novel combined treatment strategy with biomaterials to maximize therapeutic efficacy and minimize the undesirable side effects. In this study, we aimed to examine the use of the TGFßRI kinase inhibitor SD-208 and the TLR7/8 agonist resiquimod (R848) encapsulated within serum-derived EXOs for their synergistic antitumor effects. We first demonstrated that combined treatment with SD-208 and R848 can be a convincing strategy to circumvent tumor growth in vivo using serum-derived exosomes as promising carriers. Therefore, we believe this manuscript would be of great interest to the biomaterial communities especially who are studying immunotherapy.


Assuntos
Antineoplásicos , Exossomos , Neoplasias da Próstata , Adjuvantes Imunológicos , Animais , Antineoplásicos/uso terapêutico , Corantes Fluorescentes/uso terapêutico , Humanos , Masculino , Camundongos , Neoplasias da Próstata/tratamento farmacológico , Receptor 7 Toll-Like/agonistas , Fatores de Crescimento Transformadores/uso terapêutico
5.
Macromol Biosci ; 21(7): e2100067, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33963822

RESUMO

Here, as a proof of concept, hybrid vesicles (VEs) are developed from two types of cancer cells, MCF-7 and HeLa, for the dual targeting of the anticancer drug doxorubicin (Dox) to cancer cells via homotypic interactions. Hybrid VEs with a size of 181.8 ± 28.2 nm and surface charge of -27.8 ± 1.9 mV are successfully prepared by the fusion of MCF-7 and HeLa VEs, as demonstrated by the fluorescence resonance energy transfer assay. The hybrid VEs exhibit enhanced intracellular uptake both in MCF-7 and HeLa cells. Dox-encapsulated hybrid VEs (Dox-hybrid VEs) also exhibit promising anticancer and antiproliferative activities against MCF-7/multidrug-resistant cells and HeLa cells. In addition, compared to free Dox, the Dox-hybrid VEs exhibit low intracellular uptake and reduced cytotoxicity for RAW264.7 cells. Thus, hybrid VEs with dual-targeting activity toward two types of cancer cells may be useful for the specific targeting of anticancer drugs for improved anticancer effects with reduced nonspecific toxicity.


Assuntos
Antineoplásicos , Neoplasias , Antineoplásicos/farmacologia , Doxorrubicina/farmacologia , Resistencia a Medicamentos Antineoplásicos , Células HeLa , Humanos , Células MCF-7
6.
J Ginseng Res ; 44(2): 267-273, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32148408

RESUMO

BACKGROUND: Continuous exposure to high temperatures can lead to heat stress. This stress response alters the expression of multiple genes and can contribute to the onset of various diseases. In particular, heat stress induces oxidative stress by increasing the production of reactive oxygen species. The liver is an essential organ that plays a variety of roles, such as detoxification and protein synthesis. Therefore, it is important to protect the liver from oxidative stress caused by heat stress. Korean ginseng has a variety of beneficial biological properties, and our previous studies showed that it provides an effective defense against heat stress. METHODS: We investigated the ability of Korean Red Ginseng and Korean black ginseng extracts (JP5 and BG1) to protect against heat stress using a rat model. We then confirmed the active ingredients and mechanism of action using a cell-based model. RESULTS: Heat stress significantly increased gene and protein expression of oxidative stress-related factors such as catalase and SOD2, but treatment with JP5 (Korean Red Ginseng extract) and BG1 (Korean black ginseng extract) abolished this response in both liver tissue and HepG2 cells. In addition, JP5 and BG1 inhibited the expression of inflammatory proteins such as p-NF-κB and tumor necrosis factor alpha-α. In particular, JP5 and BG1 decreased the expression of components of the NLRP3 inflammasome, a key inflammatory signaling factor. Thus, JP5 and BG1 inhibited both oxidative stress and inflammation. CONCLUSIONS: JP5 and BG1 protect against oxidative stress and inflammation induced by heat stress and help maintain liver function by preventing liver damage.

7.
Sci Rep ; 10(1): 2075, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32034213

RESUMO

The blue-green alga Spirulina maxima is a microscopic filamentous cyanobacterium. Spirulina was recently reported to elicit beneficial effects such as reducing cholesterol and inducing weight loss; however, its effects on inflammation are unknown. To determine the effect of S. maxima extract (SME) on innate immunity, we investigated the NLRP3 inflammasome activation, which is a multiprotein scaffolding complex that plays important roles in innate immune responses to many pathogenic infections in macrophages. SME suppressed lipopolysaccharide (LPS)-induced upregulation of the pro-inflammatory cytokines tumor necrosis factor-α, interleukin (IL)-12, IL-1ß, and IL-18 in RAW264.7 cells. In addition, SME attenuated LPS-induced NLRP3 inflammasome activation, and thus pro-IL-1ß could not be cleaved to IL-1ß by activated caspase-1, which is activated by the NLRP3 inflammasome in RAW264.7 cells. Moreover, SME inhibited LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK) in RAW264.7 cells, and attenuated the generation of ERK1 induced-reactive oxygen species (ROS), resulting in decreased expression of NF-κB. These findings suggest that SME suppresses the effects of the NLRP3 inflammasome via regulation of extracellular signal-regulated kinase (ERK). In summary, we demonstrated that SME prevents activation of the NLRP3 inflammasome by inhibiting ERK signaling.


Assuntos
Inflamassomos/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Spirulina/química , Animais , Anti-Inflamatórios/farmacologia , Western Blotting , Citocinas/metabolismo , Humanos , Inflamassomos/metabolismo , Interleucina-18/metabolismo , Interleucina-1beta/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Células RAW 264.7/efeitos dos fármacos , Células RAW 264.7/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células THP-1/efeitos dos fármacos , Células THP-1/metabolismo
8.
Front Oncol ; 9: 752, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31632899

RESUMO

Tumor metastasis is the end state of a multistep process that includes dissemination of tumor cells to distant organs and requires tumor cells to adapt to different tissue microenvironments. During metastasis, tumor cells undergo a morphological change known as transdifferentiation or the epithelial-to-mesenchymal transition (EMT). In normal embryonic development, the EMT occurs in the context of morphogenesis in a variety of tissues. Over the course of this process, epithelial cells lose their cell-cell adhesion and polarity properties. In this study, we investigated whether magnolol could suppress the EMT in human colorectal cancer cells. To this end, we examined the epithelial markers E-cadherin, ZO-1, and claudin and the mesenchymal markers N-cadherin, TWIST1, Slug, and Snail. Magnolol effectively inhibited EMT in human colon cancer cell lines by upregulating epithelial markers and downregulating mesenchymal markers. The EMT is induced by the TGF-ß signaling pathway. To determine whether magnolol disrupts TGF-ß signaling, we examined several mediators of this pathway, and found that magnolol decreased the levels of phosphorylated (i.e., active) ERK, GSK3ß, and Smad. We conclude that magnolol blocks migration in HCT116 cells by suppressing TGF-ß signaling.

9.
Phytomedicine ; 65: 153064, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31645009

RESUMO

BACKGROUND: Obesity develops when dietary energy intake exceeds energy expenditure, and can be associated with metabolic syndrome. Recent studies have shown that dietary phytochemicals can promote energy expenditure by inducing the browning of white adipose tissue (WAT). PURPOSE: This study investigated whether cardamonin induces the browning of 3T3-L1 adipocytes through the activation of protein kinase A (PKA). METHODS: Anti-obesity potential of cardamonin was evaluated in 3T3-L1 adipocytes. Adipocyte-specific genes were observed using western blot, qPCR analysis and immunocytochemistry. RESULTS: Cardamonin treatment inhibited lipid droplet accumulation and reduced the expression of the adipogenic proteins C/EBPα and FABP4, and the lipogenic proteins LPAATθ, lipin 1, DGAT1, SREBP1, and FAS. Cardamonin also induced the expression of the browning marker genes PRDM16, PGC1α, and UCP1 at the mRNA and protein levels, and induced mRNA expression of CD137, a key marker of beige adipocytes. It also increased the expression of the ß-oxidation genes CPT1 and PPARα at the mRNA and protein levels. In addition, cardamonin increased PKA phosphorylation and the mRNA and protein expression of the downstream lipolytic enzymes adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL). CONCLUSION: Our findings demonstrate novel effects of cardamonin to stimulate adipocyte browning, suppress lipogenesis, and promote lipolysis, implying it may have potential as an anti-obesity agent.


Assuntos
Adipócitos/efeitos dos fármacos , Fármacos Antiobesidade/farmacologia , Chalconas/farmacologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Lipogênese/efeitos dos fármacos , Células 3T3-L1 , Adipócitos/metabolismo , Adipócitos/patologia , Adipogenia/efeitos dos fármacos , Adipogenia/genética , Animais , Regulação da Expressão Gênica/efeitos dos fármacos , Lipase/metabolismo , Lipólise/efeitos dos fármacos , Camundongos , Oxirredução/efeitos dos fármacos , Esterol Esterase/metabolismo , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismo
10.
J Ginseng Res ; 43(2): 252-260, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30976163

RESUMO

BACKGROUND: Increases in the average global temperature cause heat stress-induced disorders by disrupting homeostasis. Excessive heat stress triggers an imbalance in the immune system; thus protection against heat stress is important to maintain immune homeostasis. Korean ginseng (Panax ginseng Meyer) has been used as a herbal medicine and displays beneficial biological properties. METHODS: We investigated the protective effects of Korean ginseng extracts (KGEs) against heat stress in a rat model. Following acclimatization for 1 week, rats were housed at room temperature for 2 weeks and then exposed to heat stress (40°C/2 h/day) for 4 weeks. Rats were treated with three KGEs from the beginning of the second week to the end of the experiment. RESULTS: Heat stress dramatically increased secretion of inflammatory factors, and this was significantly reduced in the KGE-treated groups. Levels of inflammatory factors such as heat shock protein 70, interleukin 6, inducible nitric oxide synthase, and tumor necrosis factor-alpha were increased in the spleen and muscle upon heat stress. KGEs inhibited these increases by down-regulating heat shock protein 70 and the associated nuclear factor-κB and mitogen-activated protein kinase signaling pathways. Consequently, KGEs suppressed activation of T-cells and B-cells. CONCLUSION: KGEs suppress the immune response upon heat stress and decrease the production of inflammatory cytokines in muscle and spleen. We suggest that KGEs protect against heat stress by inhibiting inflammation and maintaining immune homeostasis.

11.
Bioconjug Chem ; 30(6): 1690-1701, 2019 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-31018638

RESUMO

Microspheres (MS; 1-3 µm) with different degrees of surface roughness were prepared to assess the effects of surface topology on internalization into antigen-presenting cells (APCs; macrophages and dendritic cells). In this study, we demonstrated that the intracellular uptake of MS is readily enhanced by surface modification with nanoparticles or cancer cell-derived vesicles (VE) to modulate their surface topology. MS coated with nanovesicles (MS-VE) with high surface roughness was more successfully and efficiently engulfed by APCs, compared with bare MS and those with low surface roughness. Incorporated MPLA within MS-VEs (M/MS-VE) triggered greatly elevated release of immune stimulating cytokines, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), from macrophages and dendritic cells, compared to free MPLA. Taken together, this MS-VE could serve as a platform system for the delivery of immune stimulators and antigens to APCs with negligible toxicity.


Assuntos
Células Apresentadoras de Antígenos/imunologia , Micropartículas Derivadas de Células/imunologia , Neoplasias/imunologia , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/imunologia , Células A549 , Animais , Células Dendríticas/imunologia , Humanos , Imunização/métodos , Interleucina-6/imunologia , Macrófagos/imunologia , Camundongos , Células RAW 264.7 , Fator de Necrose Tumoral alfa/imunologia
12.
J Environ Manage ; 232: 330-335, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30496962

RESUMO

Acetaldehyde removal tests were performed to compare the catalytic activity of the Kraft lignin char (KC), KOH-treated Kraft lignin char (KKC), and activated carbon (AC) along with their impregnation with Mn in a plasma reactor. The gasification characteristics (syngas content, and H2/CO ratio) of yellow poplar were investigated using nickel catalysts supported on KC, KKC, AC, and γ-Al2O3 in a U-type quartz reactor. KKC and Mn/KKC improved significantly the surface area and contents of O and N functional groups over the raw char. In particular, Mn/KKC showed the highest acetaldehyde-removal efficiency. The catalytic activity of Ni-impregnated KC, KKC, AC, and γ-Al2O3 decreased in the order of Ni/KKC > Ni/AC > Ni/KC > Ni/γ-Al2O3 for the gas yield and Ni/γ-Al2O3 >Ni/KC > Ni/AC >Ni/KKC for the oil yield, respectively. The Ni/KKC provides a more conducive environment for gasification, resulting in larger amounts of syngas (H2 and CO) in the product gases. Moreover, Ni impregnated with char may be the most inexpensive and effective solution for achieving maximum tar reduction and syngas generation.


Assuntos
Acetaldeído , Gases , Biomassa , Catálise , Lignina , Metais
13.
Int J Mol Sci ; 18(11)2017 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-29137190

RESUMO

Spirulina maxima, a microalga containing high levels of protein and many polyphenols, including chlorophyll a and C-phycocyanin, has antioxidant and anti-inflammatory therapeutic effects. However, the mechanisms where by Spirulina maxima ameliorates cognitive disorders induced by amyloid-ß 1-42 (Aß1-42) are not fully understood. In this study, we investigated whether a 70% ethanol extract of Spirulina maxima (SM70EE) ameliorated cognitive impairments induced by an intracerebroventricular injection of Aß1-42 in mice. SM70EE increased the step-through latency time in the passive avoidance test and decreased the escape latency time in the Morris water maze test in Aß1-42-injected mice. SM70EE reduced hippocampal Aß1-42 levels and inhibited amyloid precursor protein processing-associated factors in Aß1-42-injected mice. Additionally, acetylcholinesterase activity was suppressed by SM70EE in Aß1-42-injected mice. Hippocampal glutathione levels were examined to determine the effects of SM70EE on oxidative stress in Aß1-42-injected mice. SM70EE increased the levels of glutathione and its associated factors that were reduced in Aß1-42-injected mice. SM70EE also promoted activation of the brain-derived neurotrophic factor/phosphatidylinositol-3 kinase/serine/threonine protein kinase signaling pathway and inhibited glycogen synthase kinase-3ß phosphorylation. These findings suggested that SM70EE ameliorated Aß1-42-induced cognitive impairments by inhibiting the increased phosphorylation of glycogen synthase kinase-3ß caused by intracerebroventricular injection of Aß1-42 in mice.


Assuntos
Glicogênio Sintase Quinase 3 beta/metabolismo , Aprendizagem em Labirinto , Transtornos da Memória/tratamento farmacológico , Extratos Vegetais/uso terapêutico , Spirulina/química , Acetilcolinesterase/metabolismo , Peptídeos beta-Amiloides/administração & dosagem , Peptídeos beta-Amiloides/toxicidade , Animais , Glutationa/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Injeções Intraventriculares , Masculino , Transtornos da Memória/etiologia , Camundongos , Camundongos Endogâmicos ICR , Fragmentos de Peptídeos/administração & dosagem , Fragmentos de Peptídeos/toxicidade , Fosforilação , Extratos Vegetais/farmacologia , Processamento de Proteína Pós-Traducional
14.
Environ Pollut ; 215: 314-321, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27213572

RESUMO

This study compared the two most frequently used disinfectants (i.e., chlorine and ozone) to understand their efficiency in wastewater effluents and the ecotoxicity of disinfection by-products created during chlorination and ozonation. Four trihalomethanes (THMs) and nine haloacetic acids (HAAs) were measured from a chlorine-disinfected sample and two aldehydes (i.e., formaldehydes and acetaldehydes) were analyzed after ozonation. Chlorination was effective for total coliform removal with Ct value in the range of 30-60 mg-min/L. Over 1.6 mg/L of ozone dose and 0.5 min of the contact time presented sufficient disinfection efficiency. The concentration of THMs increased with longer contact time (24 h), but that of HAAs showed little change with contact time. The measured concentration of formaldehyde at the ozone dose of 1.6 mg/L and the contact time of 9 min showed the greatest value in this study, approximately 330 µg L(-1), from which the corresponding ecotoxicity was determined using an indicator species, Daphnia magna. The ecotoxicity results were consistent with the toxicological features judged by occurrence, genotoxicity, and carcinogenicity. Both the disinfection efficiency as well as the DBP formation potential should therefore be considered to avoid harmful impacts on aquatic environments when a disinfection method is used for wastewater effluents.


Assuntos
Cloro/química , Daphnia/efeitos dos fármacos , Desinfetantes/química , Desinfecção/métodos , Halogenação , Ozônio/química , Águas Residuárias/química , Acetaldeído/análise , Acetaldeído/toxicidade , Animais , Cloro/toxicidade , Cloroacetatos/análise , Cloroacetatos/toxicidade , Desinfetantes/toxicidade , Formaldeído/análise , Formaldeído/toxicidade , Ozônio/toxicidade , Trialometanos/análise , Trialometanos/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos
15.
Artigo em Inglês | MEDLINE | ID: mdl-22486672

RESUMO

Air streams commonly emitted from industrial sources generally contain various mixtures of volatile organic compounds (VOCs), and these complex mixtures can present challenges with respect to bioreactor design and applications. In this study, therefore, a modified Monod-type model using interaction parameters was employed to describe the biodegradation kinetics of mixtures of aromatic compounds by a Pseudomonas isolate. In addition, the model and estimated parameters were utilized to predict the performance of a bubble-column bioreactor for the treatment of mixtures of benzene, toluene, p-xylene, and styrene (BTXS). Benzene, toluene and styrene, as individual substrates, were actively degraded by the bacterial culture, whereas p-xylene was not degraded as a single substrate. Relative to the single substrate experiments, the degradation of benzene and toluene was inhibited by the other compounds, while the degradation of styrene was significantly stimulated in the presence of the other BTXS compounds. The cometabolic degradation of p-xylene was observed in the presence of benzene and toluene. The estimated interaction parameters indicated that the degradation of benzene was substantially inhibited in the presence of styrene, whereas the degradation of styrene was strongly stimulated by toluene. The kinetic coefficients and interaction parameters were used to successfully predict the biodegradation kinetics and performance of a bioreactor subjected to the quaternary mixture. Overall, the model was able to provide reasonable predictions when substrate interactions, including inhibition, stimulation, and cometabolism, play significant roles in biodegradation processes.


Assuntos
Poluentes Atmosféricos/metabolismo , Derivados de Benzeno/metabolismo , Benzeno/metabolismo , Reatores Biológicos , Filtração , Pseudomonas/metabolismo , Biodegradação Ambiental , Simulação por Computador , Cinética , Modelos Biológicos
16.
J Hazard Mater ; 194: 385-92, 2011 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-21872983

RESUMO

A combined reaction, consisting of granular activated carbon (GAC) adsorption and catalytic oxidation, has been proposed to improve the removal efficiencies of formaldehyde, one of the major indoor air pollutants. In this study, silver nano-particles attached onto the surface of GAC (Ag-GAC) using the sputtering method were evaluated for the simultaneous catalytic oxidation and adsorption of formaldehyde. The evolution of CO(2) from the silver nano-particles indicated that formaldehyde was catalytically oxidized to its final product, with the oxidation kinetics expressed as pseudo-first order. In addition, a packed column test showed that the mass of formaldehyde removed by the Ag-GAC was 2.4 times higher than that by the virgin GAC at a gas retention time of 0.5s. However, a BET analysis showed that the available surface area and micro-pore volume of the Ag-GAC were substantially decreased due to the deposition of the silver nano-particles. To simulate the performance of the Ag-GAC, the homogeneous surface diffusion model (HSDM), developed for the prediction of the GAC column adsorption, was modified to incorporate the catalytic oxidation taking place on the Ag-GAC surface. The modified HSDM demonstrated that numerical simulations were consistent with the experimental data collected from the Ag-GAC column tests. The model predictions implied that the silver nano-particles deposited on the GAC reduced the adsorptive capacity due to decreasing the available surface for the diffusion of formaldehyde into the GAC, but the overall mass of formaldehyde removed by the Ag-GAC was increased due to catalytic oxidation as a function of the ratio of the surface coverage by the nano-particles.


Assuntos
Carbono/química , Formaldeído/isolamento & purificação , Nanopartículas Metálicas , Modelos Teóricos , Prata/química , Adsorção , Difusão , Cinética , Microscopia Eletrônica de Varredura , Termodinâmica
17.
J Nanosci Nanotechnol ; 11(2): 1714-7, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21456274

RESUMO

Amine-functionalized SBA-15 materials were synthesized by a post synthesis method. Surface area and pore size decreased by attaching functional groups to the pore surface. Furthermore, pore volume was reduced with functionalization. The carbon and nitrogen content gradually increased with the number of amine groups in the silane precursors. Among the amine-functionalized SBA-15 materials, the SBA-15/TMSPDETA showed the highest removal activity given its high reactivity with formaldehyde.

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