Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
J Food Sci Technol ; 52(7): 4600-6, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26139931

RESUMEN

To prevent the development and spread of spoilage/pathogenic microorganisms via meat foodstuffs, antimicrobial nanocomposite packaging can serve as a potential alternative. The objective of this study was to develop a new class of antimicrobial hybrid packaging mat composed of biodegradable polyurethane supplemented with virgin olive oil and zinc oxide via electrospinning. Instead of mixing antimicrobial compounds directly with food, incorporation in packaging materials allows the functional effect at food surfaces where microbial activity is localized. The nanofibers were characterized by SEM, EDX, XRD and TEM. The antibacterial activity was tested against two common foodborne pathogens viz., Staphylococcus aureus and Salmonella typhimurium. The present results indicated that incorporation of olive oil in the polymer affected morphology of PU nanofibers and nanocomposite packaging were able to inhibit growth of pathogens. Thus; as-spun mat can be used as prospective antimicrobial packaging, which potentially reduces contamination of meat/meat-products. Moreover, introduced biodegradable packaging for meat products could serve to replace PVC films and simultaneously help to protect natural environment.

2.
Colloids Surf B Biointerfaces ; 123: 664-72, 2014 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-25456994

RESUMEN

Nanoscale gold particles (Au-NPs) with a diameter below 20nm are notably important candidates for various important applications because of their extraordinary quantum size effects. Their high surface area-to-volume ratio facilitates their very high reactivities; therefore, they can be utilised in different ways in biomedical applications. For example, these nanoparticles can penetrate into cells and bind with proteins or DNA and are therefore potential nanostructures employed for sensing and detecting various biological identities. In the present work, we synthesised Au-NPs via a colloidal process using chloroauric acid (HAuCl4·4H2O) and trisodium citrate dihydrate (N3C6H5O7) as a reducing agent. The shape evolution and the structural properties of these NPs were investigated in detail using TEM and high resolution HR-TEM investigations. Different doses of Au NPs have been applied to treat C2C12 myoblast cells in a 24-h incubation period, and a dose-dependent study has also been performed. The cells were cultivated in DMEM with FBS and antibiotics (strepto-penicillin) at 37°C in a 5% humidified environment of CO2 and 95% air. Cell viability analysis using MTT assays revealed that increased concentration of Au NPs (100-1000 ng/mL) resulted in a decreased density of cells. The amount of reactive oxygen species (ROS) in C2C12 cells analysed with Au-NPs (in a dose-dependent manner), and the RT-PCR data demonstrated the up-regulation of caspase-3 and caspase-7 genes in C2C12 cells after treatment with Au-NPs. These results have been confirmed by detailed confocal microscopy (CLSM) studies. In addition, the quantitative analysis of the Au-NPs was also confirmed by statistical analytical parameters, such as precision, accuracy, linearity, limits of detection (LOD) and limit of quantitation (LOQ), quantitative recoveries and relative standard deviation (RSD), and the analyses again exhibited a significant and large effect of Au NPs on C2C12 cells.


Asunto(s)
Oro/química , Nanopartículas del Metal/química , Mioblastos/citología , Mioblastos/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Caspasa 3/metabolismo , Caspasa 7/metabolismo , Ratones , Especies Reactivas de Oxígeno/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
3.
J Biomed Nanotechnol ; 9(3): 441-9, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23621000

RESUMEN

The well-crystallized ZnO nanoparticles were synthesized by a simple and facile soft chemical approach, and their induction of oxidative stress in Cloudman S91 melanoma cancer cells was studied. The ZnO nanoparticles were characterized for their morphology, structure, and optical properties. The ZnO nanoparticles with the average size of approximately 10 nm grew in high density, possessing wurtzite hexagonal phase. To study the induction of oxidative stress by ZnO nanoparticles in Cloudman S91 melanoma cancer cells, various doses of ZnO nanoparticles were treated with melanoma cancer cells for 24 h of incubation at 37 degrees C. The viability of the cells was analyzed with MTT method, whereas the morphology of the cells was observed via confocal laser scanning microscopy (CLSM), which revealed that when the time interval was increased, the number of cells decreased. The apoptosis-correlated, intracellular production of reactive oxygen species (ROS) was also measured with melanoma cancer cells with varying ZnO nanoparticle doses.


Asunto(s)
Melanoma Experimental/patología , Nanopartículas/toxicidad , Estrés Oxidativo/efectos de los fármacos , Neoplasias Cutáneas/patología , Óxido de Zinc/toxicidad , Animales , Muerte Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Ratones , Microscopía Confocal , Nanopartículas/ultraestructura , Oxidantes/toxicidad , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos X , Óxido de Zinc/síntesis química
4.
Appl Microbiol Biotechnol ; 97(12): 5545-53, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23467821

RESUMEN

We report herein the synthesis and characterization of copper oxide quantum dots and their cytotoxic impact on mouse C2C12 cells. The utilized CuO quantum dots were prepared by the one-pot wet chemical method using copper acetate and hexamethylenetetramine as precursors. The physicochemical characterization of the synthesized CuO quantum dots was carried out using X-ray diffraction, energy-dispersive X-ray analysis, and transmission electron microscopy. To examine the in vitro cytotoxicity, C2C12 cell lines were treated with different concentrations of as-prepared quantum dots and the viability of cells was analyzed using Cell Counting Kit-8 assay at regular time intervals. The morphology of the treated C2C12 cells was observed under a phase-contrast microscope, whereas the quantification of cell viability was carried out via confocal laser scanning microscopy. To gain insight into the mechanism of cell death, we examined the effect of CuO quantum dots on the candidate genes such as caspases 3 and 7, which are key mediators of apoptotic events. In vitro investigations of the biological effect of CuO quantum dots have shown that it binds genomic DNA, decreases significantly the viability of cells in culture in a concentration (10-20 µg/mL) dependent manner, and inhibits mitochondrial caspases 3 and 7. To sum up, the elucidation of the pathways is to help in understanding CuO quantum dot-induced effects and evaluating CuO quantum dot-related hazards to human health.


Asunto(s)
Apoptosis/efectos de los fármacos , Caspasa 3/metabolismo , Caspasa 7/metabolismo , Cobre/toxicidad , Mioblastos/efectos de los fármacos , Puntos Cuánticos/toxicidad , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Fenómenos Químicos , Ratones , Microscopía Electrónica de Transmisión , Microscopía de Contraste de Fase , Mioblastos/fisiología , Espectrometría por Rayos X , Difracción de Rayos X
5.
Colloids Surf B Biointerfaces ; 106: 170-5, 2013 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-23434708

RESUMEN

The objective of our study was to develop a new class of Fe3O4 nanocrystals decorated CNFs with characteristic porous morphology by straightforward approach. The utilized CNFs-Fe3O4 hybrid was prepared by sol-gel electrospinning employing polyacrylonitrile and iron (III) nitrate nonahydrate as precursors. Scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction techniques were employed to characterize novel CNFs-Fe3O4 composite. Nanofibers are having porous morphology, diameter size in the range of ~260±20 nm. In order to demonstrate the broad applicability of CNFs-Fe3O4 scaffold, we performed different analysis. The antibacterial activity was tested using Escherichia coli as model organism. With NIH 3T3 mouse fibroblasts, cytotoxicity of prepared high aspect ratio CNFs-Fe3O4 composite was evaluated by thiazoyl blue tetrazolium-bromide (MTT) assay, and fibroblast cell growth behavior with electrospun porous scaffolds was also examined. Interestingly, the prepared nanofibers exhibited enhanced bactericidal performance (minimum inhibition concentrations (MIC) from 5 µg/mL to 80 µg/mL) and CNFs-Fe3O4 composite as scaffolds indicated favorable enhancement in cell proliferation. Results from this study suggest that CNFs-Fe3O4 scaffold with small diameters coincidence with unique porous configuration can mimic the natural extracellular matrix (ECM) well and provide potential promises for applications in the fields of tissue engineering and regenerative medicine. Our findings clearly suggest wide application potentials of this (CNFs-Fe3O4) multifunctional composite and the nanofiberous mat can be a very good candidate as a filter for water purification, antibiofouling filtration and ECM for tissue engineering.


Asunto(s)
Carbono , Compuestos Férricos/química , Nanofibras , Animales , Ratones , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Células 3T3 NIH , Espectrometría por Rayos X , Difracción de Rayos X
6.
Appl Microbiol Biotechnol ; 97(10): 4523-31, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23306644

RESUMEN

We explored electrospinning as a feasible and practicable mode for encapsulation and stabilization of Lactobacillus gasseri. The utilized nanocomposite was prepared using sol-gel composed of animate L. gasseri and inanimate PVA. The objective was to examine the ability of electrospinning method to protect functional properties of probiotic L. gasseri. The PVA was used as an encapsulation matrix as it is biocompatible and hydrophilic in nature thus facilitate an easy revival of bacteria. The characterization of as-spun bioproduct was done by energy-dispersive X-ray spectrometer, SEM, and TEM, whereas thermal behavior was analyzed by thermogravimetry. The viability was confirmed by traditional pour plate method and fluorescence microscopy. Furthermore, to test whether the functionality of L. gasseri was affected, the encapsulated L. gasseri were fed to mouse for colonization. Our results pointed out that encapsulated bacteria were viable for months, and their metabolism was not affected by immobilization; thus, they could be used in food engineering and trade.


Asunto(s)
Industria de Alimentos , Lactobacillus/metabolismo , Alcohol Polivinílico/metabolismo , Animales , Ratones
7.
Colloids Surf B Biointerfaces ; 101: 424-9, 2013 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-23010050

RESUMEN

This study was aimed at the synthesis and characterization of novel Titania nanorods by sol-gel electrospinning technique. The physicochemical properties of the synthesized nanorods were determined by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and X-ray diffraction (XRD) pattern. To examine the in vitro cytotoxicity, mouse myoblast C2C12 cells were treated with different concentrations of as prepared TiO(2) nanorods and the viability of cells was analyzed by Cell Counting Kit-8 assay at regular time intervals. The morphological features of the cells attached with nanorods were examined by Bio-SEM. Cytotoxicity experiments indicated that the mouse myoblast cells could attach to the TiO(2) nanorods after being cultured. We observed that TiO(2) nanorods could support cell adhesion and growth and guide spreading behavior of myoblasts. We conclude that the electrospun TiO(2) nanorods scaffolds with unique morphology had excellent biocompatibility. Thus, the current work demonstrates that the as-synthesized TiO(2) nanorods represent a promising biomaterial to be exploited for various tissue engineering applications.


Asunto(s)
Adhesión Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Mioblastos/efectos de los fármacos , Titanio/química , Titanio/farmacología , Animales , Materiales Biocompatibles , Línea Celular , Supervivencia Celular/efectos de los fármacos , Indicadores y Reactivos , Ratones , Microscopía Confocal , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Nanotubos , Andamios del Tejido , Difracción de Rayos X
8.
Appl Microbiol Biotechnol ; 97(4): 1725-34, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22918299

RESUMEN

Zinc oxide (ZnO) nanostructures have been commonly studied for electronic purposes due to their unique piezoelectric and catalytic properties; however, recently, they have been also exploited for biomedical applications. The purpose of this study was to fabricate ZnO-doped poly(urethane) (PU) nanocomposite via one-step electrospinning technique. The utilized nanocomposite was prepared by using colloidal gel composed of ZnO and PU, and the obtained mats were vacuum dried at 60 °C overnight. The physicochemical characterization of as-spun composite nanofibers was carried out by X-ray diffraction pattern, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron probe microanalysis, and transmission electron microscopy, whereas the thermal behavior was analyzed by thermogravimetric analysis. The viability, attachment, and proliferation of NIH 3T3 mouse fibroblast cells on the ZnO/PU composite nanofibers were analyzed by in vitro cell compatibility test. The morphological features of the cells attached on nanofibers were examined by Bio-SEM. We conclude that the electrospun nanofibrous scaffolds with unique spider nets had good biocompatibility. Cytotoxicity experiments indicated that the mouse fibroblasts could attach to the nanocomposite after being cultured. Thus, the current work demonstrates that the as-synthesized ZnO/PU hybrid nanofibers represent a promising biomaterial to be exploited for various tissue engineering applications.


Asunto(s)
Materiales Biocompatibles/química , Nanofibras/química , Poliuretanos/química , Ingeniería de Tejidos/instrumentación , Andamios del Tejido/química , Óxido de Zinc/química , Animales , Supervivencia Celular , Técnicas Electroquímicas , Ratones , Microscopía Electrónica , Células 3T3 NIH , Difracción de Rayos X
9.
Appl Opt ; 52(35): 8540-8, 2013 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-24513899

RESUMEN

The vertical profile of atmospheric temperature is a principal state variable to study atmospheric stability. A lidar system, constructed using a 355 nm Nd:YAG laser transmitter, measures the temperature profile using the rotational Raman technique. In comparison with traditional Raman lidar, the major innovations are the use of a low peak power and high repetition rate laser to achieve eye-safe operation in a compact reliable instrument and the use of an angle tuning filter to select operating wavelengths. We demonstrate the capability of both nighttime and daytime measurements as a step toward a future stand-alone capability for routine measurements of important meteorological properties in the lower atmosphere.


Asunto(s)
Monitoreo del Ambiente/instrumentación , Ojo/efectos de la radiación , Rayos Láser , Fotometría/instrumentación , Protección Radiológica/instrumentación , Espectrometría Raman/instrumentación , Termografía/instrumentación , Atmósfera/análisis , Diseño de Equipo , Humanos , Lentes , Temperatura
10.
Mater Sci Eng C Mater Biol Appl ; 33(2): 707-13, 2013 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-25427477

RESUMEN

We report the fabrication of novel Fe3O4/TiO2 hybrid nanofibers with the improved cellular response for potential tissue engineering applications. In this study, Fe3O4/TiO2 hybrid nanofibers were prepared by facile sol-gel electrospinning using titanium isopropoxide and iron(III) nitrate nonahydrate as precursors. The obtained electrospun nanofibers were vacuum dried at 80 °C and then calcined at 500 °C. The physicochemical characterization of the synthesized composite nanofibers was carried out by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and X-ray diffraction pattern. To examine the in vitro cytotoxicity, satellite cells were treated with as-prepared Fe3O4/TiO2 and the viability of cells was analyzed by Cell Counting Kit-8 assay at regular time intervals. The morphological features of unexposed satellite cells and exposed to Fe3O4/TiO2 composite were examined with a phase contrast microscope whereas the quantification of cell viability was carried out via confocal laser scanning microscopy. The morphology of the cells attached to hybrid matrix was observed by Bio-SEM. Cytotoxicity experiments indicated that the satellite cells could attach to the Fe3O4/TiO2 composite nanofibers after being cultured. We observed that Fe3O4-TiO2 composite nanofibers could support cell adhesion and growth. Results from this study therefore suggest that Fe3O4/TiO2 composite scaffold with small diameters (approximately 200 nm) can mimic the natural extracellular matrix well and provide possibilities for diverse applications in the field of tissue engineering and regenerative medicine.


Asunto(s)
Materiales Biocompatibles/química , Compuestos Férricos/química , Nanofibras/química , Titanio/química , Animales , Materiales Biocompatibles/farmacología , Materiales Biocompatibles/toxicidad , Bovinos , Adhesión Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Compuestos Férricos/toxicidad , Nanofibras/toxicidad , Células Satélite del Músculo Esquelético , Andamios del Tejido/química , Titanio/toxicidad
11.
J Biomed Nanotechnol ; 8(3): 424-31, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22764411

RESUMEN

The cytotoxic effect towards myoblast cancer cells (C3C12) of well-crystalline colloidal Pt quantum dots (QDs) was examined and presented in this paper. The Pt QDs were synthesized by facile colloidal process and characterized by transmission electron microscopy (TEM) and high-resolution TEM (HR-TEM), which confirmed that the QDs are prepared in high-density, possessing a well-crystalline structure. To examine the cytotoxicity, various doses of as-prepared QDs were treated with C2C12 myoblast cancer cells at different incubation intervals; 24, 48, 72, and 96 hours, and the viability of cells was analyzed with MTT assay. The detailed analyses revealed that in the presence of Pt-QDs, with increasing the incubation time, the number of cancer cells decreases. Moreover, with increasing concentration of Pt-QDs, the cancer cell death increases, confirming that the concentration of Pt-QDs has a significant role in controlling the number of cancer cells. The present research demonstrated that Pt-QDs can efficiently be used as anticancer agents.


Asunto(s)
Neoplasias de los Músculos/patología , Neoplasias de los Músculos/fisiopatología , Platino (Metal)/administración & dosificación , Platino (Metal)/química , Puntos Cuánticos , Animales , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Citotoxinas/administración & dosificación , Citotoxinas/química , Ensayo de Materiales , Ratones , Neoplasias de los Músculos/tratamiento farmacológico
12.
In Vitro Cell Dev Biol Anim ; 48(3): 175-85, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22271316

RESUMEN

Studies on skeletal muscle cell specification and development have demonstrated in the past that calpains interact with various transcriptional factors in regulating the cellular function. It has therefore, been assumed that transcriptional factors like myogenin, MyoD, Myf5, and MRF4 that are active during the myogenic differentiation might be affected and degraded by calpains. Therefore, to examine the biochemical adaptations of myoblasts during myocyte formation and muscle development comprehensively, the current study was designed to identify the effect of calpeptin (calpain inhibitors) on protein expression during differentiation of C2C12 mouse myoblast. Cells were proliferated to near 80% confluence under Dulbecco's modified eagle medium and differentiated further in 2% HS with 50 µM calpeptin. Incubated cells were collected at 0, 12, and 72 h and later the cell proteins were focused onto pH 4-7 IEF strip, followed by 12.5% SDS-PAGE. Obtained spots on the gels were compared and matched using commercial 2-DE analysis software and matched spots were identified by MALDI-ToF and/or Q-Tof systems. Conclusively, cell differentiation was observed to be active from 12 to 72 h however, calpeptin affected the differentiation process and cut down the rate of fusion by approximately 50%. Out of 41 proteins identified, 12 proteins were found to be upregulated where as 29 proteins were downregulated.


Asunto(s)
Calpaína/metabolismo , Diferenciación Celular , Dipéptidos/metabolismo , Mioblastos/citología , Animales , Calpaína/genética , Dipéptidos/genética , Regulación del Desarrollo de la Expresión Génica , Ratones , Desarrollo de Músculos , Mapas de Interacción de Proteínas , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
13.
Asian-Australas J Anim Sci ; 25(9): 1205-15, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25049682

RESUMEN

This study was conducted to establish genetic criteria for phenotypic characteristics of Hanwoo cattle based on allele frequencies and genetic variance analysis using microsatellite markers. Analysis of the genetic diversity among 399 Hanwoo cattle classified according to nose pigmentation and coat color was carried out using 22 microsatellite markers. The results revealed that the INRA035 locus was associated with the highest Fis (0.536). Given that the Fis value for the Hanwoo INRA035 population ranged from 0.533 (white) to 1.000 (white spotted), this finding was consistent with the loci being fixed in Hanwoo cattle. Expected heterozygosities of the Hanwoo groups classified by coat colors and degree of nose pigmentation ranged from 0.689±0.023 (Holstein) to 0.743±0.021 (nose pigmentation level of d). Normal Hanwoo and animals with a mixed white coat showed the closest relationship because the lowest DA value was observed between these groups. However, a pair-wise differentiation test of Fst showed no significant difference among the Hanwoo groups classified by coat color and degree of nose pigmentation (p<0.01). Moreover, results of the neighbor-joining tree based on a DA genetic distance matrix within 399 Hanwoo individuals and principal component analyses confirmed that different groups of cattle with mixed coat color and nose pigmentation formed other specific groups representing Hanwoo genetic and phenotypic characteristics. The results of this study support a relaxation of policies regulating bull selection or animal registration in an effort to minimize financial loss, and could provide basic information that can be used for establishing criteria to classify Hanwoo phenotypes.

14.
J Biol Inorg Chem ; 16(3): 431-42, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21140179

RESUMEN

ZnO nanostructures of diverse shape were grown via a solution process with different precursors and conditions. Morphological investigation of the nanostructures was carried out using field emission scanning electron microscopy and transmission microscopy observations and revealed that the nanostructures exhibit a wurtzite phase with an ideal lattice fringe distance of approximately 0.52 nm. The powder crystallinity was examined via X-ray diffraction spectroscopy. Screening results from anticancer studies of the effects on human brain tumor U87, cervical cancer HeLa, and normal HEK cells of ZnO nanostructures of diverse shape were obtained and indicate promising activity that varies with changes in the structure and the size of the particles. Treatment-induced cell death [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and survival assay], growth inhibition, cytogenetic damage (formation of micronuclei), and apoptosis were studied as parameters for the cellular response. Treatment with nanostructures enhanced growth inhibition and cell death in a concentration-dependent manner in both U87 and HeLa cell lines. At higher concentrations (above 15.6 µg/ml) the cytotoxic effects of the nanoparticles were highly synergistic and mainly mediated through apoptosis, implying the possible interactions of lesions caused by the agents. The enhanced cell death due to nanoparticles was accompanied by a significant increase (2-3 fold at 31.25 µg/ml) in the formation of micronuclei in U87 cells. The increase in the formation of micronuclei observed after treatment indicates that these structures may interfere with the rejoining of DNA strand breaks. Among all the nanostructures, nanoparticles and sheets exhibited potent activity against both HeLa and U87 cells. However, despite potent in vitro activity, all nanostructures exhibited diminished cytotoxicity against normal human HEK cells at all effective concentrations.


Asunto(s)
Nanoestructuras/ultraestructura , Óxido de Zinc/farmacología , Apoptosis/efectos de los fármacos , Neoplasias Encefálicas/genética , Línea Celular , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Células HeLa , Humanos , Micronúcleos con Defecto Cromosómico/efectos de los fármacos , Nanoestructuras/química , Difracción de Rayos X , Óxido de Zinc/química
15.
Anim Genet ; 39(5): 550-3, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18557975

RESUMEN

Pigmentation genes such as TYR (tyrosinase), TYRP1 (tyrosinase-related protein 1), DCT (previously TYRP2, or tyrosinase-related protein 2), ASIP (agouti) and MC1R (melanocortin receptor 1) play a major role in cattle coat colour. To understand the genotypic profile underlying coat colour in native Korean Hanwoo cattle and Angus black cattle, portions of the above-mentioned genes were amplified. Sequence analysis revealed variation in the TYRP1 (exon 5) and MC1R genes. Restriction enzyme analysis of these two genes could distinguish between different colours of Hanwoo cattle. Quantitative estimates of melanin and eumelanin in hair from three different-coloured Hanwoo phenotypes and Angus black showed significant differences at the breed and phenotypic levels. Finally, sequence variants in MC1R were associated with total melanin and eumelanin in breeds as well as in Hanwoo phenotypes.


Asunto(s)
Bovinos/genética , Cabello/metabolismo , Oxidorreductasas/genética , Pigmentación/genética , Receptor de Melanocortina Tipo 1/genética , Animales , Exones , Cabello/anatomía & histología , Melaninas/genética
16.
Chemosphere ; 71(5): 879-85, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-18166213

RESUMEN

Automobile shredder residue (ASR) was pretreated to improve its quality for fuel utilization. Composition analysis revealed that ASR components could be classified into four groups: (1) urethane and textile-light fraction and combustibles containing low levels of ash and Cl; (2) plastics and rubber-light or heavy fraction and combustibles containing high levels of Cl; (3) metals and electrical wire-heavy fraction and incombustibles, and (4) particles smaller than 5.6mm with high ash contents. Based on these results, we successively performed sieving to remove particles smaller than 5.6mm, float and sink separations to reject the heavy fraction and plastics and rubber containing Cl, thermal treatment under an inert atmosphere to remove Cl derived from PVC, and char washing to remove soluble chlorides. This series of pretreatments enabled the removal of 78% of the ash and 91% of the Cl from ASR. Sieving using a 5.6-mm mesh removed a considerable amount of ash. Product quality was markedly improved after the float and sink method. Specifically, the sink process using a 1.1 g cm(-3) medium fluid rejected almost all rubber containing Cl and a large amount of PVC. The remaining Cl in char, after heating at 300 degrees C under an inert atmosphere and washing, was considered to be present as insoluble chlorides that volatilized at temperatures above 300 degrees C. Based on a tradeoff relationship between product quality and treatment cost, ASR may be utilized as a form of refuse plastic fuel or char.


Asunto(s)
Automóviles , Cloro/aislamiento & purificación , Eliminación de Residuos/métodos , Calor , Tamaño de la Partícula
17.
Waste Manag ; 28(1): 3-14, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-17267198

RESUMEN

To evaluate carbonization as a thermal pretreatment method for landfilling, the releasing characteristics of organic and inorganic constituents from carbonization residue derived from shredded residue of bulky waste was investigated by means of batch and column leaching tests. Shredded residue of bulky waste itself and its incineration ash were tested together to compare pretreatment methods. In batch leaching tests at a liquid/solid ratio of 10, the release of organic carbon from carbonization residue was at a remarkably low level. Besides, carbonization contributed to immobilize heavy metals such as chromium, cadmium, and lead within its residue. In column tests, the discharges of organic constituents were lowest from carbonization residue under aerobic conditions due to microbial activity. The leaching of Cd, Cr, Pb, and Cu from carbonization residue was suppressed under anaerobic conditions; however, this suppression effect tended to be weaker under aerobic conditions. From the results showing that the total releasing amounts of organic and inorganic constituents from carbonization residue are so low as to be comparable to that of incineration ash, carbonization can be considered as one of the thermal pretreatment methods of organic wastes.


Asunto(s)
Contaminantes Ambientales/química , Eliminación de Residuos/métodos , Contaminación Ambiental/prevención & control , Calor , Concentración de Iones de Hidrógeno , Metales , Contaminantes Químicos del Agua/química
18.
Waste Manag ; 28(2): 424-34, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-17317141

RESUMEN

This study characterized and removed ash from waste-derived char to improve the quality of char as fuel. Municipal solid waste (MSW) and automobile shredder residue (ASR) were carbonized at 450 degrees C and at 500 degrees C, respectively, in a rotary kiln with a nitrogen atmosphere for 1h. MSW and ASR char were subjected to sieving and pulverization-sieving to screen incombustibles and the ash-rich fraction, after which float-sink separation, froth floatation, and oil agglomeration were applied to remove ash from the char. The established target quality was (1) less than 30% ash content and (2) more than 20,000 kJ/kg heating value. However, the rate of combustibles recovery had to be lowered to produce a good quality of char along with a high heating value. MSW char attained the targeted quality level using froth floatation or oil agglomeration, whereas, neither separation method was able to make ASR-derived char satisfy the target. Based on the assumption that particle properties of char are determined by the weight ratio of combustibles and ash, the densities of combustibles and ash in char were estimated using the results of float-sink separation, X-ray diffraction (XRD) analysis, and elemental content. To verify the above assumption, an energy dispersive X-ray/scanning electron microscope (EDX/SEM) analyzer was used to observe char particles.


Asunto(s)
Incineración , Administración de Residuos/métodos , Automóviles , Residuos
19.
Chemosphere ; 68(10): 1913-9, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17433411

RESUMEN

The pyrolysis residue (SP) of sewage sludge (SS) produced at 500 degrees C was subjected to batch and column leaching tests to investigate the release of its organic and inorganic constituents and metals. For comparison, incineration ash (SI) obtained from a SS incinerator was also tested. Pyrolysis and incineration reduced organic matter of SS from 0.78 kg kg(-1)-dry SS to 0.16 and 0.01 kg kg(-1)-dry SS, respectively. Heavy metals remained in SP without being volatilized, although Cd and Pb were transferred into the off-gas during incineration. In the batch leaching test with the leaching liquid-to-solid mass ratio (L/S)=10, the pH of the SS, SP, and SI filtrates was 6.3, 7.9, and 11.0, respectively. The total organic carbon concentrations were in the order SS (877 l mg l(-1))>>SP (99 mg l(-1))>SI (26 mg l(-1)). The SP and SI filtrates met the landfill standard for the Cd and Pb concentrations (<0.3 mg l(-1)). In the column tests, although the SP contained more organic matter than that of SI, its carbon discharge into the leachate under aerobic conditions was similar to that of SI under anaerobic conditions. The leaching of heavy metals, such as Cd, Cr, Pb, and Zn, was also suppressed in SP during the active decomposition of organic matter. We demonstrated that pyrolysis reduces the potential release of pollutants from sewage sludge in landfill, making it a promising method of treating sewage sludge before landfilling.


Asunto(s)
Incineración , Aguas del Alcantarillado/análisis , Contaminantes Químicos del Agua/química , Carbono/química , Concentración de Iones de Hidrógeno , Metales Pesados/química , Nitrógeno/química
20.
Waste Manag ; 27(9): 1155-66, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-16920347

RESUMEN

Carbonization is a kind of pyrolysis process to produce char from organic materials under an inert atmosphere. In this work, chars derived from various solid wastes were characterized from the standpoint of fuel recovery and pretreatment of waste before landfilling. Sixteen kinds of municipal and industrial solid wastes such as residential combustible wastes, non-combustible wastes, bulky wastes, construction and demolition wastes, auto shredder residue, and sludges were carbonized at 500 degrees C for 1h under nitrogen atmosphere. In order to evaluate the quality of char as fuel, proximate analysis and heating value were examined. The composition of raw waste had a significant influence on the quality of produced char. The higher the ratio of woody biomass in waste, the higher heating value of char produced. Moreover, an equation to estimate heating value of char was developed by using the weight fraction of fixed carbon and volatile matter in char. De-ashing and chlorine removal were performed to improve the quality of char. The pulverization and sieving method seems to be effective for separation of incombustibles such as metal rather than ash. Most char met a 0.5 wt% chlorine criterion for utilization as fuel in a shaft blast furnace after it was subjected to repeated water-washing. Carbonization could remove a considerable amount of organic matter from raw waste. In addition, the leaching of heavy metals such as chrome, cadmium, and lead appears to be significantly suppressed by carbonization regardless of the type of raw waste. From these results, carbonization could be considered as a pretreatment method for waste before landfilling, as well as for fuel recovery.


Asunto(s)
Eliminación de Residuos/métodos , Carbono/química , Cloro/química , Calor , Metales/análisis , Residuos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...