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1.
J Physiol Pharmacol ; 74(5)2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38085521

RESUMEN

Clove plant (Syzygium aromaticum) is one of the Myrtaceae family. It's a common flavor in food and the traditional medicine. The study's objective was to ascertain whether the clove bud aqueous extract (CAE) and CAE + nanosilver have any biological effects on immune cells and HT-29 colon cancer cell line. Nanosilver was produced through green synthesis approach using CAE. Produced nanosilver was characterized via electron microscope (scanning, SEM) and ultraviolet-visible spectroscopy. CAE and CAE + nanosilver were examined for their active biomolecules using FTIR analysis, p53 contents using real-time PCR, apoptosis and cell cycle arrest power on HT-29 cancer cell line via flow cytometerty and immunomodulatory potential utilizing MTT assay. Results cleared that a spherical nanosilver with a diameter range of 53 nm was formed by CAE. There were several active biomolecules in CAE and CAE + nanosilver. CAE and CAE + nanosilver increased the p53 protein expression and apoptotic cell number in HT-29 colon cancer cells. CAE and CAE + nanosilver could arrest HT-29 cells at the phase G2/M. CAE and CAE + nanosilver stimulated quiescent and PHA-pre-treated splenic cells at higher concentrations, and CAE suppressed quiescent splenic cell when diluted. In conclusion, the safe edible Syzygium aromaticum plant can be utilized to make anti-tumor agent, essentially for colon tumor. As Syzygium aromaticum plant could stimulate immune cells, it can be used as immune-stimulatory agent that can help fight tumor and tumor development.


Asunto(s)
Neoplasias del Colon , Nanopartículas del Metal , Syzygium , Humanos , Plata/farmacología , Plata/química , Syzygium/química , Proteína p53 Supresora de Tumor , Extractos Vegetales/farmacología , Extractos Vegetales/química
2.
J Chem Phys ; 159(20)2023 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-38010333

RESUMEN

Semiconductor-based photocatalysts have become increasingly used in the removal of pollutants from wastewater, especially antibiotics. A series of composite-based cuprous oxide and bismuth vanadate (Cu2O/BiVO4) composite-based photocatalysts were synthesized by using the chemical method. The structure of the Cu2O/BiVO4 composite was verified by using x-ray diffraction, scanning electron microscopy, photoluminescence, Fourier transform infrared spectroscopy, and UV-visible spectra. The degradation of methylene blue (MB) and tetracycline (TC) was investigated to check the photocatalytic activity of the Cu2O/BiVO4 composite series. The quantity of Cu2O was varied from 1% to 7% by weight to prepare the series of Cu2O/BiVO4 composites. The analysis of results verified that 5% Cu2O/BiVO4 exhibits an outstanding photocatalytic activity as compared to 1%, 3%, and 7% Cu2O/BiVO4, pure Cu2O, and pure BiVO4 under visible light irradiation. The optimum value of photocatalytic degradation achieved with 5% Cu2O/BiVO4 was 97% for MB dye and 95% for TC in 120 min, which is greater than the photocatalytic degradation of pure BiVO4 (MB 45% and TC 72%), pure Cu2O (MB 57% and TC 80%), 1% Cu2O/BiVO4 (MB 72% and TC 85%), 3% Cu2O/BiVO4 (MB 83% and TC 88%), and 7% Cu2O/BiVO4 (MB 87% and TC 91%). The stability and reusability of Cu2O/BiVO4 were also investigated. To check the major role of trapping in degradation, a trapping experiment was also performed by using three trapping agents: BQ, EDTA, and tBuOH. The results showed that Cu2O/BiVO4 exhibits an improved photocatalytic activity in the degradation of antibiotics in polluted water because the recombination rate of the electron-hole pair decreased and the surface area increased, which increased the active sites for redox reactions. Such a photocatalytic composite with high efficiency has various applications, such as energy production, environmental remediation, and water remediation.

3.
Chemosphere ; 341: 139979, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37659517

RESUMEN

Over the past 50 years, the emergence of plastic waste as one of the most urgent environmental problems in the world has given rise to several proposals to address the rising levels of contaminants associated with plastic debris. Worldwide plastic production has increased significantly over the last 70 years, reaching a record high of 359 million tonnes in 2020. China is currently the world's largest plastic producer, with a share of 17.5%. Of the total marine waste, microplastics account for 75%, while land-based pollution accounts for responsible for 80-90%, and ocean-based pollution 10-20% only in overall pollution problems. Even at small dosages (10 µg/mL), microplastics have been found to cause toxic effects on human and animal health. This review examines the sources of microplastic contamination, the prevalent reaches of microplastics, their impacts, and the remediation methods for microplastic contamination. This review explains the relationship between the community composition and the presence of microplastic particulate matter in aquatic ecosystems. The interaction between microplastics and emerging pollutants, including heavy metals, has been linked to enhanced toxicity. The review article provided a comprehensive overview of microplastic, including its fate, environmental toxicity, and possible remediation strategies. The results of our study are of great value as they illustrate a current perspective and provide an in-depth analysis of the current status of microplastics in development, their test requirements, and remediation technologies suitable for various environments.


Asunto(s)
Restauración y Remediación Ambiental , Microplásticos , Animales , Humanos , Plásticos , Ecosistema , Contaminación Ambiental
4.
Environ Sci Pollut Res Int ; 30(45): 100828-100844, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37644270

RESUMEN

Tobacco products are widely recognized as a major contributor to death. Cigarette smoke contains several toxic chemicals including heavy metals particulate causing high health risks. However, limited information has been available on the health risks associated with the heavy metals in cigarettes commonly sold in the Bangladeshi market. This study evaluated the concentrations and potential health risks posed by ten concerned heavy metals in ten widely consumed cigarette brands in Bangladesh using an atomic absorption spectrometer. The concentration (mg/kg) ranges of heavy metals Pb, Cd, Cr, As, Co, Ni, Mn, Fe, Cu, and Zn vary between 0.46-1.05, 0.55-1.03, 0.80-1.2, 0.22-0.40, 0.46-0.78, 2.59-3.03, 436.8-762.7, 115.8-184.4, 146.6-217.7, and 34.0-42.7, respectively. We assume that the heavy metals content among cigarette brands is varied due to the differences in the source of tobacco they use for cigarette preparation. The carcinogenic risks posed by heavy metals follow the order of Cr > Co > Cd > As > Ni > Pb, while the non-carcinogenic risks for Cu, Zn, Fe, and Mn were greater than unity (HQ > 1), except for Fe. The existence of toxic heavy metals in cigarette tobacco may thus introduce noticeable non-carcinogenic and carcinogenic health impacts accompanying inhalation exposure. This study provides the first comprehensive report so far on heavy metal concentration and associated health risks in branded cigarettes commonly sold in Bangladesh. Hence, this data and the information provided can serve as a baseline as well as a reference for future research and have potential implications for policy and legislation in Bangladesh.

5.
Sci Rep ; 13(1): 1631, 2023 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-36717602

RESUMEN

The zizphus seeds are considered as a biomaterial residues that has been used for removing of organic industrial waste such as 2-((10-octyl-9,10-dihydroanthracene-2-yl) methylene) malononitrile (PTZS-CN) dye from aqueous solutions utilizing graphene oxide-Ziziphus (GO-Ziziphus). A batch study explored the impacts of various experimental circumstances, including solution pH, initial dye concentration, temperature, and contact time. General order, nonlinear pseudo-first order and pseudo-second order, elvoich model and intraparticiple diffusion were utilized to analyze the kinetic data. The adsorption kinetics of dye onto GO-ziziphus adsorption was best mentioned by nonlinear pseudo-first order. Similarly, the intra-particle diffusion plots revealed one exponential line throughout the adsorption process. The Freundlich, Dubinin-Radushkevich, and Langmuir models were employed to examine isothermal data. It provided the best fit of the dye adsorption isothermal data onto GO-ziziphus Freundlich models. Besides, the calculated free energies showed that the adsorption progression was physical adsorption. Thermodynamic calculations revealed that dye adsorption onto GO-ziziphus was exothermic and spontaneous. The combined results indicated that GO-ziziphus powder might be used to treat dye-rich wastewater effectively.

6.
Sci Rep ; 12(1): 18860, 2022 11 07.
Artículo en Inglés | MEDLINE | ID: mdl-36344554

RESUMEN

A unique sperm behavior was observed in Egyptian chickens. Sperm showed a tendency to agglutinate forming motile thread-like bundles. Sperm agglutination behavior, kinematics, and some morphometric measures were studied in relation to sperm competition and fertility duration in Sharkasi and Dandarawi chickens. Sperm tendency to agglutinate was assessed by examining sperm morphology using scanning electron microscopy, Acridine orange-stained semen smears using fluorescence microscopy, and recording videos of sperm under phase contrast microscope. Sperm velocity and morphometric measures were evaluated using image-J software. To assess sperm competition, Sharkasi and Dandarawi hens were artificially inseminated by semen pools possessing equal number of Sharaksi and Dandarawi sperm. Artificial insemination was repeated ten times. The eggs obtained were incubated, and the hatchlings were discriminated as descending from Sharkasi or Dandarawi fathers according to their phenotype. To assess the fertility duration, Sharkasi and Dandarawi hens were inseminated by semen collected from roosters of the same strain. Eggs were collected for a period of 28 days post-insemination and incubated. Sharkasi spermatozoa showed higher tendency to agglutinate forming longer and thicker motile bundles. No significant differences were observed in sperm curvilinear and straight line velocity and in sperm morphometric measures between Sharkasi and Dandarawi chickens. Sharkasi roosters fathered 81.6% and 67.7% of the hatchlings produced by Sharkasi and Dandarawi mothers, respectively. The fertility period in Sharkasi and Dandarawi was 22 and 14 days, respectively. We suggest that the differences seen in sperm competitiveness and fertility duration can be attributed to sperm agglutination behavior.


Asunto(s)
Pollos , Semen , Animales , Masculino , Femenino , Fertilidad , Espermatozoides , Inseminación Artificial/veterinaria , Motilidad Espermática
7.
Flow Turbul Combust ; 109(4): 961-990, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36397974

RESUMEN

Particulate flow in closed space is involved in many engineering applications. In this paper, the prediction of particle removal is investigated in a thermally driven 3D cavity at turbulent Rayleigh number Ra = 109 using Coarse Large Eddy Simulation (CLES). The depletion dynamics of SiO2 aerosol with aerodynamic diameters between 1.4 and 14 µm is reported in an Euler/Lagrange framework. The main focus of this work is therefore to assess the effect of the subgrid-scale motions on the prediction of the particulate flow in a buoyancy driven 3D cavity flow when the mesh resolution is coarse and below optimal LES standards. The research is motivated by the feasibility of modeling more complex particulate flows with reduced CPU cost. The cubical cavity of 0.7 m side-length is set to have a temperature difference of 39 K between the two facing cold and hot vertical walls. As a first step, the carrier fluid flow was validated by comparing the first and second-moment statistics against both previous well-resolved LES and experimental databases [Kalilainen (J. Aero Sci. 100:73-87, 2016); Dehbi (J. Aero. Sci. 103:67-82, 2017)]. First moment Eulerian statistics show a very good match with the reference data both qualitatively and quantitatively, whereas higher moments show underprediction due to the lesser spatial resolution. In a second step, six particle swarms spanning a wide range of particle Stokes numbers were computed to predict particle depletion. In particular, predictions of 1.4 and 3.5 µm particles were compared to LES and available experimental data. Particles of low inertia i.e. dp < 3.5 µm are more affected by the SGS effects, while bigger ones i.e. dp = 3.5-14 µm exhibit much less grid-dependency. Lagrangian statistics reported in both qualitative and quantitative fashions show globally a very good agreement with reference LES and experimental databases at a fraction of the CPU power needed for optimal LES.

8.
Materials (Basel) ; 15(22)2022 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-36431622

RESUMEN

This study aims to prepare graphene oxide (GO) from raw date seeds (RDSs), considered one of the available agricultural wastes in Saudi Arabia. The preparation method is done by the conversion of date seeds to lignin and then to graphite which is used in a modified Hummer's method to obtain GO. The adsorption of insoluble phenothiazine-derived dye (PTZS) over raw date Seeds (RDSs) as a low-cost adsorbent was investigated in this study. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were used to characterize (RDSs). According to the calculations, Freundlich isotherms and pseudo-second-order accurately predicted the kinetic rate of adsorption. The adsorption ability was 4.889 mg/g, and the removal rate was 93.98% GO-date Seeds mass, 11 mg/L starting dye concentration, at a temperature of 328 K, pH 9, and contact length of 30 min by boosting the PTZS solution's ionic strength. In addition, the computed free energies revealed that the adsorption process was physical. Thermodynamic calculations revealed that dye adsorption onto GO-date seeds was exothermic and spontaneous.

9.
Sci Rep ; 12(1): 13003, 2022 07 29.
Artículo en Inglés | MEDLINE | ID: mdl-35906270

RESUMEN

Fertility in birds is dependent on their ability to store adequate populations of viable sperm for extended durations in sperm storage tubules (SSTs). The exact mechanisms by which sperm enter, reside, and egress from the SSTs are still controversial. Sharkasi chicken sperm showed a high tendency to agglutinate, forming motile thread-like bundles comprising many cells. Since it is difficult to observe sperm motility and behavior inside the opaque oviduct, we employed a microfluidic device with a microchannel cross-section resembling close to that of sperm glands allowing for the study of sperm agglutination and motility behavior. This study discusses how sperm bundles are formed, how they move, and what role they may have in extending sperm residency inside the SSTs. We investigated sperm velocity and rheotaxis behavior when a fluid flow was generated inside a microfluidic channel by hydrostatic pressure (flow velocity = 33 µm/s). Spermatozoa tended to swim against the flow (positive rheotaxis) and sperm bundles had significantly lower velocity compared to lonesome sperm. Sperm bundles were observed to swim in a spiral-like motion and to grow in length and thickness as more lonesome sperm are recruited. Sperm bundles were observed approaching and adhering to the sidewalls of the microfluidic channels to avoid being swept with fluid flow velocity > 33 µm/s. Scanning and transmission electron microscopy revealed that sperm bundles were supported by a copious dense substance. The findings show the distinct motility of Sharkasi chicken sperm, as well as sperm's capacity to agglutinate and form motile bundles, which provides a better understanding of long-term sperm storage in the SSTs.


Asunto(s)
Pollos/fisiología , Motilidad Espermática , Espermatozoides/fisiología , Aglutinación , Animales , Femenino , Fertilidad/fisiología , Humanos , Masculino , Microscopía Electrónica de Rastreo/veterinaria , Microscopía Electrónica de Transmisión/veterinaria , Semen , Espermatozoides/ultraestructura
10.
J Basic Microbiol ; 59(2): 123-133, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30485461

RESUMEN

Bacteriophages (phages/viruses) need host bacteria to replicate and propagate. Primarily, a bacteriophage contains a head/capsid to encapsidate the genetic material. Some phages contain tails. Phages encode endolysins to hydrolyze bacterial cell wall. The two main classes of phages are lytic or virulent and lysogenic or temperate. In comparison with antibiotics, to deal with bacterial infections, phage therapy is thought to be more effective. In 1921, the use of phages against bacterial infections was first demonstrated. Later on, in humans, phage therapy was used to treat skin infections caused by Pseudomonas species. Furthermore, phages were successfully employed against infections in animals - calves, lambs, and pigs infected with Escherichia coli. In agriculture, for instance, phages have successfully been used e.g., Apple blossom infection, caused by Erwinia amylovora, was effectively catered with the use of bacteriophages. Bacteriophages were also used to control E. coli, Salmonella, Listeria, and Campylobacter contamination in food. Comparatively, phage display is a recently discovered technology, whereby, bacteriophages play a significant role. This review is an effort to collect almost recent and relevant information regarding applications and complications associated with the use of bacteriophages.


Asunto(s)
Infecciones Bacterianas/terapia , Bacteriófagos/fisiología , Terapia de Fagos , Agricultura , Enfermedades de los Animales/microbiología , Enfermedades de los Animales/terapia , Animales , Antibacterianos/uso terapéutico , Bacterias/patogenicidad , Bacterias/virología , Bacteriófagos/ultraestructura , Bovinos , ADN Viral , Contaminación de Alimentos/prevención & control , Inocuidad de los Alimentos , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Lisogenia/fisiología , Terapia de Fagos/historia , Terapia de Fagos/métodos , Terapia de Fagos/tendencias , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/terapia , Ovinos , Porcinos
11.
J Genet Eng Biotechnol ; 16(2): 507-512, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30733767

RESUMEN

Till now not information about myostatin MSTN gene in Egyptian goat breeds. Here we show more information about MSTN in some Egyptian goat breeds to enrich the database with new sequences for Egyptian goat breeds. Our conducted study focused on detection and identifying the MSTN gene as a candidate gene of the muscles growth trait in three goat breeds (Zaraibi, Baladi and Damascus). We found the similarity between the registered sequences with the accession numbers KY463684 for Zaraibi and KY463685 for Baladi and Chinese goat breeds of the MSTN gene deposited with international gene banks by up to 99% and some other species including sheep, cows and bull breeds with percentages of 95 to 97% and between 95 to 99%, respectively. There is also a correlation between the sequences of the registered pieces of Baladi with KY463686 and Damascus and Chinese breeds with KY441464 of MSTN deposited with international gene banks by up to 99% and some other species including sheep and bull breeds at a ratio of 99% for two pieces. Results demonstrated the deposited sequences of object are part of intron 1, exon 2 is fully sequenced with Zaraibi and Baladi breeds; the intron 1, exon 1 with Baladi breed; and the intron 2, part of exon 3 with Damascus breed. Therefore, the Egyptian goat breeds consider national wealth can be used to develop breeding and improvement programs which helps in more applicable scopes like biotechnology, genetic engineering and molecular biology with the help of bioinformatics tools.

12.
Anim Reprod Sci ; 184: 228-234, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28779946

RESUMEN

With avian sperm cryopreservation protocols, the most widely used cryoprotectants (CPAs) are the glycerol (GLY; in gradual freezing: in-straw freezing method), and the dimethylacetamide (DMA; in pellets by plunging into liquid nitrogen: in-pellet rapid freezing method). Use of both methods results in a small portion of thawed live sperm with lesser fertilizing ability compared with the semen samples immediately after collection. This study was conducted to assess the pre-freezing damage occurring to the sperm due to the interaction with the cryoprotectants (CPAs) GLY (8%) and DMA (5%), as well as the post-freezing damage resulting from both freezing methods Data for each treatment, in fresh and frozen-thawed samples, were compared for sperm motility, fertilizing capacity and sperm-egg penetration holes/germinal disc (SP holes/GD). Hens (n=50) were artificially inseminated (10 hens/treatment) six times with 3day intervals between inseminations. The treatment of fresh sperm with DMA led to a reduction (P<0.05) in the count of SP holes/GD (21.4) and the fertility rate (66.7%). The addition and elimination of GLY in fresh samples resulted in a lesser (P<0.05) number of SP holes/GD (11.8) and the fertility rate (i.e., 50.0%). The number of SP-holes/GD was least in frozen-thawed samples using both DMA and GLY (14.2 and 9.2, respectively). The fertility rate when using semen frozen with DMA in- pellets was greater (P<0.05) than with use of semen that had been frozen using GLY in straws (46.4% compared with 31.3%). The reduction in fertility compared with the control when semen was cryopreserved using GLY was 64.1%; the GLY addition and elimination was responsible for two thirds of this reduction. The reduction in fertility when using semen cryopreserved with DMA was 46.7%; half of the reduction was attributed to the treatment with DMA. In conclusion, the mechanical damage attributed to the process for reducing GLY concentrations was more harmful to sperm fertilizing capacity than the toxicity of DMA and freeze/thaw process. For both freezing methods, the amount of sperm cryo-damage was similar, when the damage attributed to the CPA addition and elimination process was excluded.


Asunto(s)
Acetamidas/farmacología , Pollos/fisiología , Crioprotectores/farmacología , Congelación , Glicerol/farmacología , Animales , Criopreservación , Fertilidad/efectos de los fármacos , Masculino
13.
Br Poult Sci ; 56(2): 195-209, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25558900

RESUMEN

The effects of dietary electrolyte balance (DEB) and electrolyte-betaine (El-Be) supplements on heat-stressed broiler performance, acid-base balance and water retention were evaluated during the period 31-40 d of age in a 2 × 3 factorial arrangement of treatments. A total of 240 broilers were assigned to 6 treatment groups each with 8 replicates of 5 birds per cage and were exposed to cyclic high temperature (32 - 24 ± 1°C). Birds were provided with diets having DEB of either 180 or 220 mEq/kg. El-Be supplements were either added to the diet, water or not added to either of them to complete the array of 6 treatment groups. An additional 80 birds were kept at thermoneutral temperature (20 ± 1°C) and were provided with tap water and diets with DEB of either 180 or 220 mEq/kg to serve as negative controls. Exposure to high temperature depressed growth performance, increased rectal temperature and decreased potassium (K(+)) retention. In high-temperature room, birds fed on diets with DEB of 220 mEq/kg tended to increase BW from 35-40 d of age. However, at thermoneutral temperature, broilers fed on diets with DEB of 220 mEq/kg increased K(+) retention. Adding El-Be supplements in feed or water improved feed conversion ratio (FCR), enhanced water consumption and increased K(+) and sodium (Na(+)) retention. Interactions between DEB and El-Be supplements tended to affect body weight gain and FCR during the periods 35-40 and 31-40 d of age, respectively. It is suggested that when using a diet with DEB of 180 mEq/kg, adding the El-Be supplements in drinking water was more beneficial than in feed. Adding the supplements in feed or water was equally useful when using DEB of 220 mEq/kg.


Asunto(s)
Betaína/metabolismo , Pollos/fisiología , Suplementos Dietéticos , Electrólitos/metabolismo , Respuesta al Choque Térmico , Equilibrio Ácido-Base , Alimentación Animal/análisis , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Betaína/administración & dosificación , Temperatura Corporal , Pollos/crecimiento & desarrollo , Dieta/veterinaria , Relación Dosis-Respuesta a Droga , Electrólitos/administración & dosificación , Masculino , Carne/análisis , Agua/metabolismo
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 136 Pt B: 993-1000, 2015 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-25459625

RESUMEN

Spectroscopic (IR, Raman, NMR, UV-visible, and ESR), and structural studies of the ligand 3-methoxy-N-salicylidene-o-amino phenol (H2L) and its synthesized complexes with some transition metal ions (Mn(II), Co(II), Ni(II)), Cu(II) and Zn(II)) were recorded and analyzed. The magnetic properties and thermal gravimetric analysis (TGA and DTA) were also measured for the complexes. The metal complexes were found to have The structural formula ML⋅H2O and the metal ions Mn(II), Co(II), Ni(II)) and Zn(II) were found to form tetrahedral complexes with the ligand whereas Cu(II) formed a square planar one. Antimicrobial activity of the ligand and its complexes were also investigated and discussed.


Asunto(s)
Antibacterianos/farmacología , Antifúngicos/farmacología , Complejos de Coordinación/farmacología , Fenol/farmacología , Bases de Schiff/química , Bases de Schiff/farmacología , Espectrometría Raman , Elementos de Transición/farmacología , Bacterias/efectos de los fármacos , Complejos de Coordinación/química , Espectroscopía de Resonancia por Spin del Electrón , Electrones , Iones , Ligandos , Fenómenos Magnéticos , Pruebas de Sensibilidad Microbiana , Fenol/química , Espectroscopía de Protones por Resonancia Magnética , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría
15.
Langmuir ; 28(9): 4051-9, 2012 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-22239672

RESUMEN

Hollow metallic nanoparticles have been attracting the attention of many researchers in the past five years due to their new properties and potential applications. The unique structure of the hollow nanoparticles; presence of two surfaces (internal and external), and the presence of both cavities and pores in the wall surfaces of these nanoparticles are responsible for their unique properties and applications. Here the galvanic replacement technique is used to prepare nanocages made of gold, platinum, and palladium. In addition, hollow double shell nanoparticles are made of two metal shells like Au-Pt, Pt-Au, Au-Pd, Pd-Au, Pd-Pt, and Pt-Pd. Silver nanocubes are used as templates during the synthesis of hollow nanoparticles with single metal shell or double shell nanocages. Most of the problems that could affect the synthesis of solid Silver nanocubes used as template as well as the double shell nanocages and their possible solutions are discussed in a detail. The sizes and shapes of the single-shell and double-shell nanocages were characterized by a regular and high-resolution TEM. A SEM mapping technique is also used to image the surface atoms for the double shell hollow nanoparticles in order to determine the thickness of the two metal shells. In addition, optical studies are used to monitor the effect of the dielectric properties of the other metals on the plasmonic properties of the gold nanoshell in these mixed nanoparticles.

16.
Nano Lett ; 11(3): 946-53, 2011 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-21302928

RESUMEN

Surface plasmon resonance (SPR) wavelength of plasmonic nanoparticles is sensitive to changes in the dielectric function of its exposed surface to the medium. Gold nanocages (AuNCs) have two surfaces (inner and outer) and thus two plasmon fields., When the dielectric of the medium changes around the outer surface only, the SPR shifts to different extent from that observed when the dielectric constant of the medium changes around both surfaces. This property of plasmonic AuNCs was used to elucidate the mechanism of the catalytic reduction of 4-nitro to 4-amino phenol, whether it is occurring within the cavity or on the exterior surface of the nanocages. For this purpose two types of nanocages were prepared, one with two plasmonic surfaces and the other with Au/Pt shell-shell nanocages, where only the external surface is plasmonic as gold is outside and Pt is inside. By following the time dependence of the plasmonic band shift resulting from the addition of the reactants and comparing the reaction kinetic parameters for two types of nanocages with those of the pure single metallic nanocages, it was concluded that the catalysis is taking place within the cavity in both types of hollow nanoparticles.


Asunto(s)
Nanopartículas , Catálisis , Microscopía Electrónica de Transmisión de Rastreo , Resonancia por Plasmón de Superficie
17.
Poult Sci ; 90(1): 157-67, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21177455

RESUMEN

Exposing broilers to a high temperature increases water and electrolyte K(+) and Na(+) excretion, which negatively affects the heat dissipation capacity and acid-base homeostasis, resulting in losses in growth performance. In this experiment, the efficacy of providing oral rehydration therapy and betaine on growth performance, acid-base balance, and water and electrolyte retention was evaluated. A total of 432 one-day-old broiler chicks (Cobb) were allocated to 72 metabolic cages and reared to 31 d of age under standard conditions. From 32 to 41 d of age, chicks were exposed to heat stress (ambient temperature, 32°C) and high RH (80 to 100% RH) for 9 h daily. The ameliorative effects of a 3 × 3 factorial array of treatments administered via drinking water were evaluated in 8 replicates of 6 chicks per cage for each treatment. Two oral rehydration therapy (ORT) fluids, based on either citrate or bicarbonate salts, were added to tap water. In addition, betaine was added to tap water at an inclusion rate of 0, 500, or 1,000 mg/L to complete the array of 9 liquid-based treatments. Growth performance was assessed at 32, 35, and 41 d of age. From 32 to 35 d of age, chicks receiving ORT fluids exhibited improved growth performance, water balance, and electrolyte (K(+), Na(+)) retention. In addition, the physiological response to stress was attenuated, as indicated by lower heterophil-to-lymphocyte ratios and blood glucose concentrations relative to the negative controls. The addition of betaine at an inclusion rate of 500 mg/L improved BW gain. From d 36 to 41, treatments did not significantly influence growth performance, which suggests that chicks receiving tap water were able to compensate and adapt to the heat-stress conditions. The results demonstrate that the beneficial effects of providing ORT fluids and 500 mg of betaine/L were observed only during the first 4 d of heat exposure. After this period, adaptation to the heat appears to occur, and none of the treatments was successful in improving growth performance.


Asunto(s)
Desequilibrio Ácido-Base/tratamiento farmacológico , Betaína/farmacología , Pollos , Fluidoterapia/veterinaria , Enfermedades de las Aves de Corral/tratamiento farmacológico , Agua/administración & dosificación , Animales , Betaína/administración & dosificación , Suplementos Dietéticos , Calor , Masculino , Estrés Fisiológico/efectos de los fármacos
18.
Nano Lett ; 10(9): 3764-9, 2010 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-20701250

RESUMEN

Five different hollow cubic nanoparticles with wall length of 75 nm were synthesized from platinum and/or palladium elements. The five nanocatalysts are pure platinum nanocages (PtNCs), pure palladium nanocages (PdNCs), Pt/Pd hollow shell-shell nanocages (NCs) (where Pd is defined as the inner shell around the cavity), Pd/Pt shell-shell NCs, and Pt-Pd alloy NCs. These are used to catalyze the reduction of 4-nitrophenol with sodium borohydride. The kinetic parameters (rate constants, activation energies, frequency factors, and entropies of activation) of each shell/shell NCs are found to be comparable to that of pure metal NCs made of the same metal coating the cavity in the shell-shell NCs. These results strongly suggest that the catalytic reaction takes place inside the cavity of the hollow nanoparticles. Because of the nanoreactor confinement effect of the hollow nanocatalysts, the frequency factors obtained from the Arrhenius plots are found to be the highest ever reported for this reduction reaction. This is the reason for enhanced rate of this reaction inside the cavity. The importance of mechanism of the homogeneous and the heterogeneous nanocatalytic reactions occurring on the external surface of a solid nanoparticle are contrasted with those occurring on the nanocavity surface.


Asunto(s)
Nanoestructuras , Catálisis , Cinética , Microscopía Electrónica de Transmisión
19.
Mymensingh Med J ; 19(2): 185-90, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20395910

RESUMEN

This study was carried out in the department of Neurosurgery, Dhaka Medical College Hospital, Dhaka, Bangladesh, during the period of January 2003 to December 2006 to elucidate the effectiveness of surgical treatment in the management of low grade astrocytoma of brain. For this purpose, a total number of 50 cases admitted during the study period with low grade astrocytoma of brain supported by clinical features and radiological investigations (CT and MRI scan) were included in this study. The mean age of the patient was a 27.3+/-16.9 year ranging from 1.8 to 65.0 years. Males (64.0%) were more in comparison to females (36.0%) with a male female ratio of 1.8:1. The main presenting complaints were headache (100%), convulsion (84.0%), vomiting (80.0%), visual impairment (20.0%), motor deficit (16.0%) and ataxia (14.0%). All cases had a definite diagnostic investigation at the time of admission. Plain x-ray skull was done in all patients followed by CT scan (70%), MRI scan (60%) and both CT and MRI scan (64.0%). Out of 50 patients 60.0% had gross total removal of tumor and 40.0% sub total tumor resection. Histopathological study was done in all cases after tumor resection. Among the gross total tumor removal cases highest percentage had good recovery (93.4%) in the immediate post operative period. Only one (3.3%) patient developed severe disability and equal percentage had moderate disability. Another 2(4.0%), those underwent subtotal tumor resection died during subsequent follow up period at 8th and 14th postoperative day.


Asunto(s)
Astrocitoma/cirugía , Neoplasias Encefálicas/cirugía , Adolescente , Adulto , Anciano , Astrocitoma/diagnóstico , Astrocitoma/mortalidad , Astrocitoma/patología , Bangladesh/epidemiología , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/patología , Niño , Preescolar , Terapia Combinada , Medios de Contraste , Femenino , Humanos , Lactante , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
20.
Mymensingh Med J ; 19(2): 239-43, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20395919

RESUMEN

This prospective study was done in Neurosurgery department, Dhaka Medical College Hospital. It was conducted from December 2002 to October 2005. During this period 40 paediatric posterior fossa tumour patients was admitted. The mean age of the patients were 8.31+/-3.1 years ranging from 3.5 to 15 years. The main complaints were headache with vomiting (100%), dimming of vision (70%), Ataxia (52.5%), Blindness (25%). All cases had a definite diagnostic investigation at the time of admission. Plain x-ray skull was done in all patients followed by MRI scan (42.5%), CT scan (37.5) and both CT and MRI scan (20%). In all cases CSF diversion (VP shunt) were instituted. All patients were operated by suboccipital craniectomy followed by gross total removal of tumour in (62.5%) and subtotal removal in (37.5%). In all cases diagnosis was confirmed by histopathological examination. In cases of subtotal resection, symptoms (headache, vomiting) appeared during 7-9 months follow up period in (7.5%) and subsequent follow up in (12.5%). But in gross total removal symptoms appeared in one case (2.5%) in 13-15 months follow up period.


Asunto(s)
Neoplasias Encefálicas/cirugía , Fosa Craneal Posterior , Adolescente , Bangladesh , Neoplasias Encefálicas/diagnóstico , Niño , Preescolar , Diagnóstico Diferencial , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Estudios Prospectivos , Tomografía Computarizada por Rayos X
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