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1.
Food Chem Toxicol ; 153: 112262, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34004227

RESUMEN

Considering the increasing demand towards "ready-to-cook" processed seafood products, recognised as being potential contributors to high sodium (Na) intake by consumers, this study aimed to assess the effect of sodium chloride (NaCl) reduction on physicochemical, microbiological and sensory properties of European seabass (Dicentrarchus labrax) sausages stored in chilling conditions during 5 weeks. Three formulations were tested in comparison with a control (100% NaCl, CTR): (i) 50% NaCl+50% ME (oleoresins microcapsules) (F1); (ii) 50% NaCl+50% KCl (F2); and (iii) only 50% NaCl (F3). The NaCl reduction mainly affected the texture and the salty taste, resulting in softer and perceived as less salty sausages after processing. However, hardness differences disappeared after 5 weeks. It seems that an antioxidant protection was obtained in sausages formulated with oleoresins microcapsules. No or low growth of psychrotrophic and mesophilic bacteria was observed (≤2.40 log CFU/g). Decreasing NaCl content and/or partially replacing it (50%) by KCl or oleoresins microcapsules seem to be suitable solutions to reduce Na (30.9-36.3%) levels, while maintaining the chilled sausages quality for 5 weeks. The partial replacement of NaCl by KCl also allows obtaining a product richer in K (997.2 mg/100 g), which ingestion may contribute for a cardiovascular protective effect.


Asunto(s)
Productos Pesqueros , Productos de la Carne , Cloruro de Sodio/química , Animales , Lubina , Cápsulas/química , Color , Productos Pesqueros/análisis , Calidad de los Alimentos , Productos de la Carne/análisis , Extractos Vegetales/química , Cloruro de Potasio/química , Gusto
2.
Int J Mol Sci ; 21(18)2020 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-32899772

RESUMEN

To ameliorate ischemia-induced graft injury, optimal organ preservation remains a critical hallmark event in solid organ transplantation. Although numerous preservation solutions are in use, they still have functional limitations. Here, we present a concise review of a modified Histidine-Tryptophan-Ketoglutarate (HTK) solution, named HTK-N. Its composition differs from standard HTK solution, carrying larger antioxidative capacity and providing inherent toxicity as well as improved tolerance to cold aiming to attenuate cold storage injury in organ transplantation. The amino acids glycine, alanine and arginine were supplemented, N-acetyl-histidine partially replaced histidine, and aspartate and lactobionate substituted chloride. Several in vitro studies confirmed the superiority of HTK-N in comparison to HTK, being tested in vivo in animal models for liver, kidney, pancreas, small bowel, heart and lung transplantation to adjust ingredients for required conditions, as well as to determine its innocuousness, applicability and potential advantages. HTK-N solution has proven to be advantageous especially in the preservation of liver and heart grafts in vivo and in vitro. Thus, ongoing clinical trials and further studies in large animal models and consequently in humans are inevitable to show its ability minimizing ischemia-induced graft injury in the sequel of organ transplantation.


Asunto(s)
Soluciones Preservantes de Órganos/química , Preservación de Órganos/métodos , Alanina , Animales , Arginina , Criopreservación/métodos , Glucosa/química , Glucosa/metabolismo , Glicina , Humanos , Hígado/efectos de los fármacos , Manitol/química , Manitol/metabolismo , Trasplante de Órganos , Páncreas/efectos de los fármacos , Cloruro de Potasio/química , Cloruro de Potasio/metabolismo , Procaína/química , Procaína/metabolismo , Daño por Reperfusión
3.
Food Chem ; 248: 192-200, 2018 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-29329843

RESUMEN

Cheese is a suitable matrix to deliver probiotic strains but it contains a high amount of sodium. The effect of partial substitution of NaCl by KCl and the addition of flavor enhancers (l-arginine, yeast and oregano extract) on probiotic Prato cheese was investigated after 1, 30, and 60 d of refrigerated storage (immediately after manufacturing, and during ripening and storage). Microbiological (lactic acid bacteria and probiotic Lactobacillus casei 01 counts and survival under gastrointestinal conditions), physicochemical (pH, proteolysis, fatty acids), bioactivity (antioxidant effect and angiotensin I-converting enzyme inhibitory activity), rheological, and water mobility by means of time domain low-field nuclear magnetic resonance were investigated. Significant changes in probiotic survival were observed; however, the sodium reduction and the addition of flavor enhancers did not constitute an obstacle to L. casei 01 (>108 CFU/g) during storage. Slight changes were observed in proteolysis, bioactivity, water mobility, texture profile, and fatty acids of the cheeses as a function of the flavor enhancer added. The sodium reduction and the supplementation of Prato cheese with probiotic cultures may be an effective alternative to the production of a potentially functional cheese.


Asunto(s)
Queso , Aromatizantes/química , Cloruro de Potasio/química , Probióticos , Cloruro de Sodio/química , Inhibidores de la Enzima Convertidora de Angiotensina/análisis , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Antioxidantes/análisis , Antioxidantes/farmacología , Queso/análisis , Queso/microbiología , Ácidos Grasos/análisis , Aromatizantes/farmacología , Calidad de los Alimentos , Alimentos Funcionales , Concentración de Iones de Hidrógeno , Lacticaseibacillus casei , Cloruro de Potasio/farmacología , Sodio/análisis , Cloruro de Sodio/farmacología
4.
Trans R Soc Trop Med Hyg ; 111(5): 204-210, 2017 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-28957470

RESUMEN

Background: Severe cholera is a life-threatening illness of hypovolemic shock and metabolic acidosis due to rapid and profuse diarrheal fluid loss. Emergency life-saving therapy is i.v. saline, optionally supplemented with potassium and alkali to correct the fluid deficit, potassium losses and acidosis. After this initial rehydration, for the next 2 days ongoing stool losses are replaced with oral rehydration solution (ORS), which contains sodium chloride, potassium and alkali together with glucose or rice powder as a source of glucose to serve as a carrier for sodium. Results: In actual field trials, antibiotics are given to reduce fluid requirements, but large volumes averaging about 7 liters of i.v. fluid followed by about 14 liters of ORS have been given to adult patients. Disturbing trends during therapy have included overhydration, hyponatremia and polyuria. Conclusions: It is suggested that stool output and fluid requirements could be reduced, if borne out in future research, by avoiding overhydration by restricting ORS intake to match stool output and promoting intestinal reabsorption of luminal fluid by early introduction of glucose without salts into the intestine, more gradual correction of dehydration, giving mineralocorticoid and vasopressin, and infusing glucose or short-chain fatty acids into the proximal colon.


Asunto(s)
Antidiarreicos/uso terapéutico , Cólera/complicaciones , Defecación , Deshidratación/terapia , Diarrea/terapia , Fluidoterapia/métodos , Antidiarreicos/administración & dosificación , Antidiarreicos/farmacología , Bicarbonatos/administración & dosificación , Bicarbonatos/química , Bicarbonatos/uso terapéutico , Cólera/terapia , Defecación/efectos de los fármacos , Deshidratación/etiología , Diarrea/tratamiento farmacológico , Diarrea/etiología , Diarrea/prevención & control , Heces , Fluidoterapia/efectos adversos , Glucosa/administración & dosificación , Glucosa/química , Glucosa/uso terapéutico , Humanos , Hiponatremia/etiología , Hiponatremia/prevención & control , Poliuria/etiología , Poliuria/prevención & control , Cloruro de Potasio/administración & dosificación , Cloruro de Potasio/química , Cloruro de Potasio/uso terapéutico , Cloruro de Sodio/administración & dosificación , Cloruro de Sodio/química , Cloruro de Sodio/uso terapéutico
5.
Food Res Int ; 91: 47-54, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-28290326

RESUMEN

Emulsions containing high acyl gellan (0.025 or 0.100% w/w) as emulsifier/stabilizer with KCl addition (1.6-15,633mg of KCl/g of gellan) were evaluated. In general a decrease in apparent viscosity and an increase of the droplets size were observed as KCl content rises. Addition of intermediate KCl concentration (62.6-1,563mg of KCl/g of gellan) could improve the stability to macroscopic phase separation of emulsions with the lower gellan concentration (0.025% w/w). However it was observed that KCl content above a critical value (1,563mg of KCl/g of gellan) caused the breakup of the emulsions containing 0.025% or 0.10% w/w of gellan, showing that emulsions properties could be easily modulated by the salt-polysaccharide ratio, allowing the formation of emulsions for different purposes. High viscosity of the continuous medium and the repulsive forces of the charged droplets were the main emulsions stabilizing mechanisms. However the formation of a physical barrier on droplets interface by deposition of gellan aggregates could be occurring at particular conditions of KCl-gellan ratio.


Asunto(s)
Emulsionantes/química , Excipientes/química , Polisacáridos Bacterianos/química , Cloruro de Potasio/química , Aceite de Girasol/química , Agua/química , Emulsiones , Tamaño de la Partícula , Propiedades de Superficie , Viscosidad
6.
Molecules ; 21(6)2016 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-27322223

RESUMEN

The Chrysactinia mexicana A. Gray (C. mexicana) plant is used in folk medicine to treat fever and rheumatism; it is used as a diuretic, antispasmodic; and it is used for its aphrodisiac properties. This study investigates the effects of the essential oil of C. mexicana (EOCM) on the contractility of rabbit ileum and the mechanisms of action involved. Muscle contractility studies in vitro in an organ bath to evaluate the response to EOCM were performed in the rabbit ileum. EOCM (1-100 µg·mL(-1)) reduced the amplitude and area under the curve of spontaneous contractions of the ileum. The contractions induced by carbachol 1 µM, potassium chloride (KCl) 60 mM or Bay K8644 1 µM were reduced by EOCM (30 µg·mL(-1)). Apamin 1 µM and charybdotoxin 0.01 µM decreased the inhibition induced by EOCM. The d-cAMP 1 µM decreased the inhibition induced by EOCM. l-NNA 10 µM, Rp-8-Br-PET-cGMPS 1 µM, d,l-propargylglycine 2 mM, or aminooxyacetic acid hemihydrochloride 2 mM did not modify the EOCM effect. In conclusion, EOCM induces an antispasmodic effect and could be used in the treatment of intestinal spasms or diarrhea processes. This effect would be mediated by Ca(2+), Ca(2+)-activated K⁺ channels and cAMP.


Asunto(s)
Íleon/efectos de los fármacos , Contracción Muscular/efectos de los fármacos , Aceites Volátiles/administración & dosificación , Parasimpatolíticos/administración & dosificación , Aceites de Plantas/administración & dosificación , Animales , Apamina/administración & dosificación , Asteraceae/química , Calcio/metabolismo , Humanos , Íleon/patología , Músculo Liso/efectos de los fármacos , Aceites Volátiles/química , Parasimpatolíticos/química , Aceites de Plantas/química , Cloruro de Potasio/química , Conejos
7.
J Food Sci ; 80(6): S1399-403, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25944263

RESUMEN

Several studies have shown the close relationship between the sodium consumption and health problems such as hypertension and cardiovascular disease. Thus, the demand for products with reduced sodium content, but with sensory quality, is increasing every day. In this context, this study aimed to optimize a low sodium salts mix using sodium chloride, potassium chloride, and monosodium glutamate to the development of shoestring potatoes with low sodium content and high sensory quality, through mixture design and response surface methodology. The salts mix that promotes the same salting power and similar sensory acceptability that the shoestring potatoes with 1.6% sodium chloride (ideal concentration) and at the same time promotes the greatest possible reduction of sodium, about 65%, should provide the composition as follows: 0.48% of sodium chloride, 0.92% of potassium chloride, and 0.43% of monosodium glutamate.


Asunto(s)
Dieta Hiposódica , Sales (Química)/química , Cloruro de Sodio/química , Solanum tuberosum , Adolescente , Adulto , Comportamiento del Consumidor , Femenino , Análisis de los Alimentos , Tecnología de Alimentos , Humanos , Masculino , Cloruro de Potasio/química , Glutamato de Sodio/química , Sodio en la Dieta , Gusto , Adulto Joven
8.
Int J Pharm ; 486(1-2): 21-9, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25772413

RESUMEN

We evaluated an analytical setup to identify optimal preparation conditions for nanoplex formation of small molecule drugs and polyelectrolytes using ciprofloxacin (CIP) and dextran sulfate (DS) as model compounds. The suitability of isothermal titration calorimetry (ITC) as a screening tool for rational formulation optimization was assessed. Besides ITC, static and dynamic light scattering, zeta potential measurements and scanning electron microscopy were applied to analyze the influence of different salt types and ionic strengths on CIP/DS nanoplex formation. The addition of low amounts of salt, especially 0.1M NaCl, improved the formation of CIP/DS nanoplexes. The presence of low amounts of salt led to smaller and more numerous particles of higher uniformity but had no influence on the release of CIP from nanoplexes. Furthermore, the molar range, within which efficient complexation was achieved, was broader in the presence of 0.1M NaCl than in the absence of salt with overall comparable complexation efficiency. Importantly, binding affinity correlated with particle shape and morphology, potentially enabling optimization of critical quality attributes based on ITC data. Altogether, ITC along with supplemental methods is a versatile screening tool for the evaluation of nanoplex formulation conditions regarding mixing ratio, salt type and ionic strength.


Asunto(s)
Antibacterianos/química , Ciprofloxacina/química , Sulfato de Dextran/química , Nanopartículas/química , Cloruro de Sodio/química , Cloruro de Calcio/química , Calorimetría , Química Farmacéutica , Liberación de Fármacos , Microscopía Electrónica de Rastreo , Nanopartículas/ultraestructura , Concentración Osmolar , Cloruro de Potasio/química
9.
J Chromatogr A ; 1381: 64-73, 2015 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-25595534

RESUMEN

The two main chromatographic modes based on hydrophobicity, hydrophobic interaction chromatography (HIC) and reversed-phase chromatography (RPC), are widely used for both analytical and preparative chromatography of proteins in the pharmaceutical industry. Despite the extensive application of these separation methods, and the vast amount of studies performed on HIC and RPC over the decades, the underlying phenomena remain elusive. As part of a systematic study of the influence of mobile phase modulators in hydrophobicity-based chromatography, we have investigated the effects of both KCl and ethanol on the retention of three insulin variants on two HIC adsorbents and two RPC adsorbents. The focus was on the linear adsorption range, separating the modulator effects from the capacity effects, but some complementary experiments at higher load were included to further investigate observed phenomena. The results show that the modulators have the same effect on the two RPC adsorbents in the linear range, indicating that the modulator concentration only affects the activity of the solute in the mobile phase, and not that of the solute-ligand complex, or that of the ligand. Unfortunately, the HIC adsorbents did not show the same behavior. However, the insulin variants displayed a strong tendency toward self-association on both HIC adsorbents; on one in particular. Since this causes peak fronting, the retention is affected, and this could probably explain the lack of congruity. This conclusion was supported by the results from the non-linear range experiments which were indicative of double-layer adsorption on the HIC adsorbents, while the RPC adsorbents gave the anticipated increased tailing at higher load.


Asunto(s)
Etanol/química , Insulina/química , Cloruro de Potasio/química , Adsorción , Cromatografía , Cromatografía de Fase Inversa , Interacciones Hidrofóbicas e Hidrofílicas , Soluciones
10.
RNA ; 20(3): 331-47, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24442612

RESUMEN

Folding mechanisms of functional RNAs under idealized in vitro conditions of dilute solution and high ionic strength have been well studied. Comparatively little is known, however, about mechanisms for folding of RNA in vivo where Mg(2+) ion concentrations are low, K(+) concentrations are modest, and concentrations of macromolecular crowders and low-molecular-weight cosolutes are high. Herein, we apply a combination of biophysical and structure mapping techniques to tRNA to elucidate thermodynamic and functional principles that govern RNA folding under in vivo-like conditions. We show by thermal denaturation and SHAPE studies that tRNA folding cooperativity increases in physiologically low concentrations of Mg(2+) (0.5-2 mM) and K(+) (140 mM) if the solution is supplemented with physiological amounts (∼ 20%) of a water-soluble neutral macromolecular crowding agent such as PEG or dextran. Low-molecular-weight cosolutes show varying effects on tRNA folding cooperativity, increasing or decreasing it based on the identity of the cosolute. For those additives that increase folding cooperativity, the gain is manifested in sharpened two-state-like folding transitions for full-length tRNA over its secondary structural elements. Temperature-dependent SHAPE experiments in the absence and presence of crowders and cosolutes reveal extent of cooperative folding of tRNA on a nucleotide basis and are consistent with the melting studies. Mechanistically, crowding agents appear to promote cooperativity by stabilizing tertiary structure, while those low molecular cosolutes that promote cooperativity stabilize tertiary structure and/or destabilize secondary structure. Cooperative folding of functional RNA under physiological-like conditions parallels the behavior of many proteins and has implications for cellular RNA folding kinetics and evolution.


Asunto(s)
Pliegue del ARN , ARN/química , ARN/fisiología , Ácido Cacodílico/química , Cinética , Magnesio/química , Mutación/genética , Conformación de Ácido Nucleico , Polietilenglicoles/química , Cloruro de Potasio/química , Termodinámica
11.
Can J Microbiol ; 59(12): 837-44, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24313456

RESUMEN

Ten hydrocarbonoclastic halobacterial species and 5 haloarchaeal species that had been isolated on a mineral medium with oil as the sole carbon source grew better and consumed more crude oil, as measured by gas-liquid chromatography, in media receiving between 0.50 and 0.75 mol/L KCl and between 1.50 and 2.25 mol/L MgSO4. Chemical analysis revealed that within a certain limit, the higher the KCl and MgSO4 concentrations in the medium, the more K⁺ and Mg²âº, respectively, was accumulated by cells of all the tested halobacteria and haloarchaea. Also, in experiments in which total natural microbial consortia in hypersaline soil and water samples were directly used as inocula, the consumption of hydrocarbons was enhanced in the presence of the above given concentrations of KCl and MgSO4. It was concluded that amendment with calculated concentrations of K⁺ and Mg²âº could be a promising practice for hydrocarbon bioremediation in hypersaline environments.


Asunto(s)
Euryarchaeota/metabolismo , Magnesio/metabolismo , Petróleo/metabolismo , Potasio/metabolismo , Salinidad , Microbiología del Suelo , Contaminantes del Suelo/metabolismo , Suelo/química , Contaminantes Químicos del Agua/metabolismo , Agua/química , Archaea/aislamiento & purificación , Archaea/metabolismo , Biodegradación Ambiental , Medios de Cultivo/química , Medios de Cultivo/metabolismo , Euryarchaeota/aislamiento & purificación , Hidrocarburos/metabolismo , Sulfato de Magnesio/química , Sulfato de Magnesio/metabolismo , Consorcios Microbianos , Cloruro de Potasio/química , Cloruro de Potasio/metabolismo
12.
Nucleic Acids Res ; 41(2): 1071-80, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23222132

RESUMEN

The Type ISP Restriction-Modification (RM) enzyme LlaBIII is encoded on plasmid pJW566 and can protect Lactococcus lactis strains against bacteriophage infections in milk fermentations. It is a single polypeptide RM enzyme comprising Mrr endonuclease, DNA helicase, adenine methyltransferase and target-recognition domains. LlaBIII shares >95% amino acid sequence homology across its first three protein domains with the Type ISP enzyme LlaGI. Here, we determine the recognition sequence of LlaBIII (5'-TnAGCC-3', where the adenine complementary to the underlined base is methylated), and characterize its enzyme activities. LlaBIII shares key enzymatic features with LlaGI; namely, adenosine triphosphate-dependent DNA translocation (∼309 bp/s at 25°C) and a requirement for DNA cleavage of two recognition sites in an inverted head-to-head repeat. However, LlaBIII requires K(+) ions to prevent non-specific DNA cleavage, conditions which affect the translocation and cleavage properties of LlaGI. By identifying the locations of the non-specific dsDNA breaks introduced by LlaGI or LlaBIII under different buffer conditions, we validate that the Type ISP RM enzymes use a common translocation-collision mechanism to trigger endonuclease activity. In their favoured in vitro buffer, both LlaGI and LlaBIII produce a normal distribution of random cleavage loci centred midway between the sites. In contrast, LlaGI in K(+) ions produces a far more distributive cleavage profile.


Asunto(s)
División del ADN , Enzimas de Restricción del ADN/metabolismo , ADN/química , ADN/metabolismo , Metilación de ADN , Enzimas de Restricción del ADN/química , Enzimas de Restricción del ADN/clasificación , Cloruro de Potasio/química , Estructura Terciaria de Proteína
13.
Luminescence ; 27(5): 357-61, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23044770

RESUMEN

The lyoluminescence (LL), thermoluminescence (TL) and mechanoluminescence (ML) of γ-ray-irradiated coloured powder of KCl:Dy (0.05-0.5 mol%) phosphors are reported in this paper. To understand the mechanism of LL and ML, the LL and ML spectra are compared with TL studies. The variation of intensity of respective luminescence with different γ-ray doses and with different concentrations of Dy3+ ion doped in KCl is found to be similar in nature. The intensities differ from each other, but their nature is found to be similar with γ-ray exposures. The ML glow peak intensity is linear up to high 1 kGy exposure as compared to LL (up to 0.5 kGy) and TL (up to 0.75 kGy) techniques. Therefore, according to our results, the recommendation is that KCl:Dy (0.1 mol%) phosphor prepared by wet chemical technique is useful for high-dose measurements using the ML technique for accidental radiation dosimetry.


Asunto(s)
Sustancias Luminiscentes/química , Cloruro de Potasio/química , Radiometría/instrumentación , Rayos gamma , Luminiscencia , Mediciones Luminiscentes
14.
J Dent ; 40(9): 750-5, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22677913

RESUMEN

OBJECTIVES: The aim of this study was to investigate the effects of decreasing fluoride concentrations on repeated demineralizing challenges on human enamel. MATERIALS AND METHODS: In 24 teeth, 3mm×3mm windows were prepared on the buccal and lingual sides and treated in a cycling demineralization-remineralization model. Remineralization was achieved with 100, 10 and 0.1 ppm fluoride from anime fluoride. Coronal sections were cut through the artificial lesions, and three sections per tooth were investigated using polarized light microscopy and scanning electron microscopy with quantitative element analysis. RESULTS: The morphology of the lesions was studied, and the extensions of the superficial layer and the body of the lesion were measured. Using element analysis, the Ca, P and F content were determined. The body of the lesion appeared remineralized after application of 100 ppm fluoride, while remineralization of the lesion was less successful after application of 10 and 0.1 ppm fluoride. The thickness of the superficial layer increased with decreasing fluoride concentrations, and also the extension of the body of the lesion increased. Ca and P content increased with increasing fluoride concentrations. CONCLUSIONS: The effectiveness of fluoride in enamel remineralization increased with increasing fluoride concentration. CLINICAL RELEVANCE: A consistently higher level of fluoride in saliva should be a goal in caries prevention.


Asunto(s)
Aminas/administración & dosificación , Cariostáticos/administración & dosificación , Esmalte Dental/efectos de los fármacos , Fluoruros/administración & dosificación , Remineralización Dental/métodos , Ácido Acético/química , Calcio/análisis , Cloruro de Calcio/química , Celulosa/análogos & derivados , Celulosa/química , Esmalte Dental/ultraestructura , Microanálisis por Sonda Electrónica , Fluoruros/análisis , Humanos , Concentración de Iones de Hidrógeno , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Microscopía de Polarización , Fosfatos/química , Fósforo/análisis , Cloruro de Potasio/química , Compuestos de Potasio/química , Saliva Artificial/química , Acetato de Sodio/química , Espectrometría por Rayos X , Temperatura , Desmineralización Dental/terapia
15.
Zhongguo Zhong Yao Za Zhi ; 37(4): 466-70, 2012 Feb.
Artículo en Chino | MEDLINE | ID: mdl-22667145

RESUMEN

OBJECTIVE: To prepare kappa-carrageenan-chitosan polyelectrolyte gel pellets and detect the effects of formulation and preparation factors on in vitro drug release from the pellets. METHOD: The K-carrageenan-chitosan polyelectrolyte gel pellets with baicalin as model drug were prepared by ionotropic gelation technique. The ratio of kappa-carrageenan/chitosan in pellets was determined with the composite of K-carrageenan and chitosan. The effects of the concentration of K-carrageenan, the ratio of drug/kappa-carrageenan, the concentration of gelling solution, gelling time and drying method on the release of pellets were determined by in vitro drug release. RESULT: The mass ratio of K-carrageenan/chitosan in pellets was 6: 4. Release of the pellets in 0.1 mol x L(-1) HCl was about 10% for 2 hours and fast in PBS, indicating a typical sustained release property. The pellets released less with the increase in the concentration of K-carrageenan, the ratio of drug/kappa-carrageenan and the concentration of KCl. They also released less with the increase in gelling time, but showed little effect until 1 hour. The release of the pellets prepared by the freeze-drying method was much faster than those by vacuum drying and atmospheric drying methods which had little influence on drug release. CONCLUSION: The K-carrageenan-chitosan polyelectrolyte gel pellets had sustained release property. Their drug release rate could be regulated with different formulation and preparation factors.


Asunto(s)
Carragenina/química , Quitosano/química , Portadores de Fármacos/química , Microesferas , Química Farmacéutica , Desecación , Electrólitos/química , Geles , Cloruro de Potasio/química , Factores de Tiempo
16.
Zhong Yao Cai ; 34(2): 171-5, 2011 Feb.
Artículo en Chino | MEDLINE | ID: mdl-21823469

RESUMEN

OBJECTIVE: To study the effects of different fertilizer applications on the yield of Fagopyrum cymosum and explore the hese scheme for getting the maximum yield on purple soil in the Chongqing-west. METHODS: Experiment with implementing plan of "3414"; The quality Assessment by the contents of bipoly-chrysanthemin; The data process program under the Excel 2003, SPSS 13.0, MatlaB 7.0, Word 2003 environments. RESULTS: Various fertilizer combinations had different transformation efficiency which the N3P2K2 combination was the maximum 97.09% and the NOP2K2 combination was the minimum 4.32%; The NOP2K2 combination had the lowest yield except of the bland group which was 186 kg/667 m2; When the N fertilizer Rate was controlled in the level of 15 kg/667 m2 The yied had no obvious change as the increase of another two kinds fertilizer rate; Three kinds of function could better reflect the relationships between fertilizer and yields, which all of the R2 value were above 0.88; The best one was N K function with the maximum R2; The blank group had maximum content 8.67% of bipoly-chrysanthemin and the content had a little decrease as the increase of N or K, but all higher than 7.14% which were planted in Bei Jing area. CONCLUSIONS: Various fertilizer combinations influenced the transformation efficiency of N, P, K;N is the key fertilizer on purple soil; Reconmentation funtion was N,K function which could be as the guiding function; F; Fertilizer would not influence the quality of Fagopyrum cymosum.


Asunto(s)
Agricultura/métodos , Fagopyrum/crecimiento & desarrollo , Fertilizantes , Rizoma/crecimiento & desarrollo , Suelo/análisis , Biomasa , Fosfatos de Calcio/química , Fosfatos de Calcio/metabolismo , Fagopyrum/metabolismo , Modelos Lineales , Nitrógeno/química , Nitrógeno/metabolismo , Cloruro de Potasio/química , Cloruro de Potasio/metabolismo , Control de Calidad , Rizoma/metabolismo
17.
Anal Chim Acta ; 699(2): 127-33, 2011 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-21704767

RESUMEN

The voltammetric behaviour of selenium(IV) was studied at platinum and gold electrodes in sulphuric acid, perchloric acid and potassium chloride media as a basis for its voltammetric detection. The best voltammetric behaviour was recorded at gold electrodes with perchloric acid as the supporting electrolyte. The concomitant presence of metals, such as copper or lead, and of model biomolecules, such as bovine serum albumin, in the solution resulted in a deterioration of the electrochemical response for selenium(IV). Quantitative detection of selenium(IV) by square wave anodic stripping voltammetry at both a millimetre-sized gold disc electrode and a microband electrode array revealed linear responses to selenium concentration in the ranges 5-15 µM and 0.1-10 µM, respectively, with 60s preconcentration. The sensitivities were 6.4 µA µM(-1) cm(-2) and 100 µA µM(-1) cm(-2) at the disc and the microband array, respectively. The detection limit at the microband electrode array was 25 nM, illustrating the potentiality of such microelectrodes for the development of mercury-free analytical methods for the trace detection of selenium(IV).


Asunto(s)
Técnicas Electroquímicas/métodos , Electrólitos/química , Selenio/análisis , Animales , Bovinos , Electrodos , Oro/química , Metales/química , Percloratos/química , Platino (Metal)/química , Cloruro de Potasio/química , Albúmina Sérica Bovina/química , Ácidos Sulfúricos/química
18.
J Am Chem Soc ; 133(18): 7121-7, 2011 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-21506566

RESUMEN

A simple, high yield, chemical process is developed to fabricate layered h-BN nanosheets and BCNO nanoparticles with a diameter of ca. 5 nm at 700 °C. The use of the eutectic LiCl/KCl salt melt medium enhances the kinetics of the reaction between sodium borohydride and urea or guanidine as well as the dispersion of the nanoparticles in water. The carbon content can be tuned from 0 to 50 mol % by adjusting the reactant ratio, thus providing precise control of the light emission of the particles in the range 440-528 nm while reaching a quantum yield of 26%. Because of their green synthesis, low toxicity, small size, and stability against aggregation in water, the as-obtained photoluminescent BCNO nanoparticles show promise for diagnostics and optoelectronics.


Asunto(s)
Compuestos de Boro/química , Cloruro de Litio/química , Luminiscencia , Nanopartículas/química , Fósforo/química , Cloruro de Potasio/química , Agua/química , Borohidruros/química , Tamaño de la Partícula , Sales (Química)/química , Solubilidad
19.
Meat Sci ; 87(3): 290-8, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21123002

RESUMEN

Fermented sausages with 25% or 50% of their NaCl replaced by KCl and supplemented with 1% or 2% concentrations of yeast extract were produced. The sausage production process was monitored with physical, chemical and microbiological analyses. After production, the sausage samples were submitted to a consumer study and their volatile compounds were extracted by solid-phase microextraction and analyzed by GC-MS. The replacement of NaCl by KCl did not significantly influence the physical, chemical or microbiological characteristics. The sensory quality of the fermented sausages with a 50% replacement was poor compared with the full-salt control samples. The use of yeast extract at a 2% concentration increased volatile compounds that arose from amino acids and carbohydrate catabolism. These compounds contributed to the suppression of the sensory-quality defects caused by the KCl introduction, thus enabling the production of safe fermented sausages that have acceptable sensory qualities with half as much sodium content.


Asunto(s)
Productos Biológicos/química , Aromatizantes/química , Aditivos Alimentarios/química , Alimentos en Conserva/análisis , Productos de la Carne/análisis , Saccharomyces cerevisiae/química , Adulto , Animales , Brasil , Bovinos , Fenómenos Químicos , Dieta Hiposódica , Fermentación , Preferencias Alimentarias , Conservantes de Alimentos/química , Humanos , Persona de Mediana Edad , Cloruro de Potasio/química , Análisis de Componente Principal , Control de Calidad , Sensación , Sus scrofa , Compuestos Orgánicos Volátiles/análisis , Compuestos Orgánicos Volátiles/química , Adulto Joven
20.
J Colloid Interface Sci ; 352(1): 1-10, 2010 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-20810126

RESUMEN

Two complementary continuum theories of electrokinetic transport are examined with particular emphasis on the equivalent conductance of binary electrolytes. The "small ion" model [R.M. Fuoss, L. Onsager, J. Phys. Chem. 61 (1957) 668] and "large ion" model [R.W. O'Brien, L.R. White, J. Chem. Soc. Faraday Trans. 2 (74) (1978) 1607] are both discussed and the "large ion" model is generalized to include an ion exclusion distance and to account in a simple but approximate way for the Brownian motion of all ions present. In addition, the "large ion" model is modified to treat "slip" hydrodynamic boundary conditions in addition to the standard "stick" boundary condition. Both models are applied to the equivalent conductance of dilute KCl, MgCl(2), and LaCl(3) solutions and both are able to reproduce experimental conductances to within an accuracy of several tenths of a percent. Despite fundamental differences in the "small ion" and "large ion" theories, they both work equally well in this application. In addition, both "stick-large ion" and "slip-large ion" models are equally capable of accounting for the equivalent conductances of the three electrolyte solutions.


Asunto(s)
Lantano/química , Cloruro de Magnesio/química , Cloruro de Potasio/química , Conductividad Eléctrica , Electrólitos/química , Electroforesis , Iones/química , Modelos Químicos , Soluciones
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