Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 14 de 14
Filter
1.
Spectrochim Acta A Mol Biomol Spectrosc ; 317: 124416, 2024 Sep 05.
Article in English | MEDLINE | ID: mdl-38733915

ABSTRACT

The effects on the structure, valence state and morphological properties of FeCo-containing SnO2 nanostructured solids were investigated. The physicochemical features were tuned by distinct synthesis routes e.g., sol-gel, coprecipitation and nanocasting, to apply them as catalysts in the glycerol valorization to cyclic acetals. Based on Mössbauer and XPS spectroscopy results, all nanosized FeCoSn solids have Fe-based phases, which contain Co and Sn included in the structure, and well-dispersed Fe3+ and Fe2+ surface active sites. Raman, FTIR and EPR spectroscopies measurements of the spent solids demonstrated structural stability for the sol-gel based solid, which is indeed responsible for the highest catalytic performance, among the nanocasted and coprecipitated counterparts. Morphological and elemental analyses illustrated distinct morphologies and composition on solid surface, depending on the synthesis route. The Fe/Co and Fe/Sn surface ratios are closely related to the catalytic performance. The improved glycerol conversion and selectivities of the solid obtained by sol-gel method was ascribed to the leaching resistance and the Sn action as a structural promoter.

2.
Dalton Trans ; 53(21): 9139-9150, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38741567

ABSTRACT

In this study, metal-doped niobates and perovskites were obtained by a solid-state reaction. The solids were evaluated in the esterification of glycerol in the presence of acetic acid to produce valuable esters of glycerol. The structural features of the solids indicated the ZnNb2O6, Pb2.8Nb2O7.8 and CuNb2O6 columbite main phases and La2MnFeO6 double-perovskite. Density functional theory (DFT) studies of Pb2.8Nb2O7.8 clearly confirmed the existence of a robust orthorhombic structure and its electronic properties were correlated with the Nb and Pb interactions. The morphological and elemental analyses also indicated that not all surface elements, as well as morphology, were crucial for catalytic properties. All solids were active and selective toward triacetin formation upon glycerol esterification with acetic acid. The catalytic performance depends mainly on the availability of the surface and its structural stability, as well as defects formation. Recyclability studies indicated that the La2MnFeO6 double-perovskite was an efficient catalyst, achieving glycerol conversion of 68% and triacetin selectivity of 25% up to 4 cycles of use in the reaction. The structural defects near the Mn4+/Mn3+ surface sites resulted in the diffusion of anions and an increased concentration of oxygen vacancies contributed to the stable performance of the solid in glycerol ester production.

3.
Cureus ; 15(8): e43202, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37692741

ABSTRACT

Background Adequate nutritional support is crucial for achieving optimal growth and development in very-low-birth-weight (VLBW) preterm infants. This study evaluated the efficacy of combined nutrition (CN) (parenteral plus enteral nutrition (EN)) as an alternative nutrition protocol for VLBW infants in the neonatal intensive care unit (NICU). Methods This retrospective cohort study collected clinical and growth data from the medical records of VLBW infants weighing between 1,000 and 1,500 grams in the NICU of the Hospital of Obstetrics and Gynecology "Dr. Víctor Manuel Espinosa de los Reyes Sánchez" of the Centro Médico Nacional "La Raza" Instituto Mexicano del Seguro Social, Mexico. Parenteral nutrition (PN) alone or CN (PN plus EN) was used for nutritional management. Statistical tests, such as Student's t-test, Mann-Whitney U test, and chi-square test as appropriate, were used to compare the clinical characteristics and growth data of the two groups, and relative risk was calculated to determine the probability of comorbidities according to feeding type. Statistical significance was set at p<0.05. Results The study included 90 VLBW infants, with 27 receiving PN alone and 63 receiving CN. No statistically significant differences were found concerning sex, age, or Apgar score. The CN group showed better weight gain with statistically significant differences at 28 days (p=0.002), with no increase in the relative risk of necrotizing enterocolitis (NEC) or other complications. Conclusions The CN protocol met the caloric and nutritional needs, without increasing morbidity and mortality. The protocol had a positive impact on weight gain and a shorter NICU stay and should be considered as a nutritional alternative for VLBW infants.

4.
Talanta ; 194: 150-157, 2019 Mar 01.
Article in English | MEDLINE | ID: mdl-30609515

ABSTRACT

A simple, fast, and laboratory efficient doped P carbon nanoparticles synthesis is developed for fingerprint imaging, using 1,3-dihydroxyacetone and di-phosphorous pentoxide. Fluorescence nanoparticles, with an average size of 230 nm were obtained, without additional energy input or external heating. ATR, solid NMR, XPS and fluorescence spectroscopy revealed their surface functionalization; a reaction mechanism is proposed. Fluorescence measurements exhibited a maximum emission band at ca. 495 nm, when excited at 385 nm. The images obtained, on different surfaces such as mobile telephone screen, magnetic band and metallic surface of a credit card and a Euro banknote treated with the obtained nano-powders allows us to record positive matches, confirming that the experimental results illustrate the effectiveness of proposed method.

5.
Chemosphere ; 219: 286-295, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30543964

ABSTRACT

Ferric chloride solutions are used as coagulants or flocculants in water treatment operations for human consumption. This treatment produces large amounts of clay-type solids formed mainly of montmorillonite with iron oxides and humic substances. This ferric sludge can be used as an efficient catalyst for the removal of volatile organic compounds (VOCs) by total oxidation. This waste isolated in the purification process has been activated by calcinations in air, characterized by several physicochemical techniques and employed as a catalyst for the removal by total oxidation of representative VOCs: toluene, propane and mixtures of toluene/propane with or without water. This ferric sludge has shown a catalytic activity one order of magnitude higher than that of a commercial iron oxide. This high activity has been related to the composition of the sludge (as it contains active metal oxides such as oxides of iron and manganese) and to the porous structure (leading to a reasonably high surface area). Moreover, it can be also used as a support for platinum, showing comparable (or even higher) catalytic activity than a similar platinum catalyst supported on conventional γ-alumina. This work presents a double environmental perspective since the material employed as a catalyst is a waste sludge and the catalytic reaction studied deals about the elimination of pollutants.


Subject(s)
Sewage/chemistry , Volatile Organic Compounds/isolation & purification , Water Purification/methods , Catalysis , Ferric Compounds/chemistry , Oxidation-Reduction , Platinum/chemistry , Volatile Organic Compounds/chemistry
6.
Materials (Basel) ; 10(10)2017 Sep 21.
Article in English | MEDLINE | ID: mdl-28934136

ABSTRACT

A synthesized functionalized pillared porous phosphate heterostructure (PPH), surface functionalized phenyl group, has been used to remove the dye Acid Blue 113 from wastewater. X-ray photoemission spectroscopy XPS and X-ray diffraction (XRD) were used to study its structure. The specific surface area of this was 498 m²/g. The adsorption capacities of PPH and phenyl surface functionalized (Φ-PPH) were 0.0400 and 0.0967 mmol/g, respectively, with a dye concentration of 10-5 M when well fitted with SIPS and Langmuir isotherms respectively (pH 6.5, 25 °C). The incorporation of the dye to the adsorbent material was monitored by the S content of the dye. It is suggested as an alternative for Acid Blue 113 remediation.

7.
J Colloid Interface Sci ; 465: 165-73, 2016 Mar 01.
Article in English | MEDLINE | ID: mdl-26674232

ABSTRACT

Carbon quantum dots (CQDs) coated with poly(amidoamine) (PAMAM-NH2) dendrimer are prepared from folic acid and phosphoric acid under a hydrothermal procedure. The obtained nanoparticles are successfully used as fluorescent sensor for Pt(IV) (in the form of chloroplatinate ion). CQDs possess many attractive features including uniform dispersion with average size about 13nm for unmodified particles and, ∼30nm when they are coated with PAMAM-NH2 dendrimer. The synthesized nanoparticles have been characterized by elemental analysis, attenuated total reflectance (ATR), X-ray photoelectron (XPS) and Raman spectroscopies, transmission electron microscopy (TEM), dynamic light scattering (DLS), and steady-state and life-time fluorescence. CQDs are used as fluorescent sensor of Pt(IV) ion in aqueous media showing linear quenching effect of their fluorescence. The results obtained demonstrated a limit of detection of 657nM with an accuracy of the method of 0.13% (as RSD, n=10) and sensitivity of 78nM. Moreover, with the presence of other interference species, good results are obtained when applied in real samples from platinum nanoparticles synthesis. The dissolved platinum ions can be quantified in the range 6-96µM with an accuracy of 2.5%.

8.
Talanta ; 134: 317-324, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25618674

ABSTRACT

We report a nanocomposite of ZnS:Mn quantum dots and a third generation PAMAM-OH dendrimer (ZnS:Mn@PAMAM-OH(G=3)) which was rationalized to be used as ratiometric nanosensor for Cd(2+) in aqueous solution. The nanoparticles exhibited a bright yellow-orange emission with peaks at 448 and 595 nm. The structure of ZnS:Mn was not changed after coupling with PAMAM-OH, which was evidenced by the analysis of the emission spectra of the compounds. The results confirm that the prepared fluorescence nanoparticles could selectively detect Cd(2+) in aqueous solution with a limit of detection of 24.34 µM and RSD 4.07%, obtained by using the ratio I448/I595. The method was applied to different water samples.

9.
Anal Chim Acta ; 812: 228-35, 2014 Feb 17.
Article in English | MEDLINE | ID: mdl-24491786

ABSTRACT

A fluorescent nanocomposite based on the inclusion of CdSe quantum dots in porous phosphate heterostructures, functionalized with amino groups (PPH-NH2@CdSe), was synthesized, characterized and used for fingerprint detection. The main scopes of this work were first to develop a friendly chemical powder for detecting latent fingerprints, especially in non-porous surfaces; their further intercalation in PPH structure enables not to spread the fluorescent nanoparticles, for that reason very good fluorescent images can be obtained. The fingerprints, obtained on different non-porous surfaces such as iron tweezers, mobile telephone screen and magnetic band of a credit card, treated with this powder emit a pale orange luminescence under ultraviolet excitation. A further image processing consists of contrast enhancement that allows obtaining positive matches according to the information supplied from a police database, and showed to be more effective than that obtained with the non-processed images. Experimental results illustrate the effectiveness of proposed methods.

10.
Arch Esp Urol ; 66(1): 152-60, 2013.
Article in Spanish | MEDLINE | ID: mdl-23406811

ABSTRACT

OBJECTIVES: We aim to analyse the role of new technologies in management of small renal cancer. METHODS: We perform a non-systematic review of the literature in Medline, Cochrane Database of Systematic Reviews between period 2000-2012, using following mesh terms: partial nephrectomy, renal ablative technologies, and renal cancer. RESULTS: We don't review in this article ablative technologies such as cryotherapy, radiofrequency, as they are the subject of others manuscripts within this monographic issue. We focus on high intensity ultrasounds (HIFU) microwaves therapy, radiosurgery, laser and water jet dissection. CONCLUSIONS: New technologies in partial nephrectomy are under constant and vertiginous evolution. Although efficacy has been demonstrated in short term and isolated studies, more studies, better designed, with bigger sample size and longer follow up are needed.


Subject(s)
Carcinoma, Small Cell/surgery , Kidney Neoplasms/surgery , Minimally Invasive Surgical Procedures/methods , Nephrectomy/methods , Urologic Surgical Procedures/methods , Cryotherapy , Humans , Laser Therapy , Microwaves , Radiosurgery , Ultrasonic Surgical Procedures
11.
Arch. esp. urol. (Ed. impr.) ; 66(1): 152-160, ene.-feb. 2013. tab, ilus
Article in Spanish | IBECS | ID: ibc-109422

ABSTRACT

OBJETIVO: Analizar el papel de las nuevas tecnologías en el manejo de los tumores renales. MÉTODOS: Se realizó una revisión no sistemática incluyendo las palabras clave nefrectomía parcial, técnicas ablativas renales, y cáncer renal en las bases de datos y fuentes de información tales como Medline, Cochrane Database of Systematic Reviews entre los periodos 2000 a 2012. RESULTADOS: No repasaremos en este artículo las técnicas ablativas para los tumores renales, tales como la crioablación, la ablación por radiofrecuencia (ARF), al ser objeto de otros artículos de este monográfico y nos centraremos en los ultrasonidos focalizados de alta intensidad (HIFU), la terapia con microondas (TM), la radiocirugía, las técnicas con láseres, y la hidrodisección. CONCLUSIONES: Las nuevas tecnologías en nefrectomía parcial tales como ultrasonidos focalizados de alta intensidad (HIFU), la terapia con microondas (TM), la radiocirugía, las técnicas con láseres, y la hidrodisección se encuentran actualmente en evolución constante y vertiginosa. Aunque han demostrado eficacia en estudios a corto plazo y aislados, se necesitan estudios mejor diseñados, con un tamaño muestral más elevado y un seguimiento más largo en el tiempo(AU)


OBJECTIVES: We aim to analyse the role of new technologies in management of small renal cancer. METHODS: We perform a non-systematic review of the literature in Medline, Cochrane Database of Systematic Reviews between period 2000-2012, using following mesh terms: partial nephrectomy, renal ablative technologies, and renal cancer. RESULTS: We don’t review in this article ablative technologies such as cryotherapy, radiofrequency, as they are the subject of others manuscripts within this monographic issue. We focus on high intensity ultrasounds (HIFU) microwaves therapy, radiosurgery, laser and water jet dissection. CONCLUSIONS: New technologies in partial nephrectomy are under constant and vertiginous evolution. Although efficacy has been demonstrated in short term and isolated studies, more studies, better designed, with bigger sample size and longer follow up are needed(AU)


Subject(s)
Humans , Male , Female , Nephrectomy/instrumentation , Nephrectomy/methods , /methods , /trends , Kidney Neoplasms/complications , Kidney Neoplasms/diagnosis , Ablation Techniques/instrumentation , Ablation Techniques/methods , Nephrectomy/trends , Nephrectomy , Kidney Neoplasms/physiopathology , Kidney Neoplasms/surgery , Kidney Neoplasms , Microwaves/therapeutic use , Radiosurgery/methods , Radiosurgery
12.
Chemosphere ; 72(4): 608-15, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18485445

ABSTRACT

Copper based catalysts supported on mesoporous materials, which were in turn based on a surfactant expanded zirconium phosphate for the formation of silica galleries in the interlayer space, were prepared by the impregnation method. They were then characterised and tested in the selective catalytic reduction of NO with ammonia as active catalysts for the control of the NOx emissions from heavy duty vehicles. Copper catalysts displayed a high catalytic performance, even in the presence of 14% (v/v) of H2O and 100 ppm of SO2. They also displayed improved catalytic behaviour when compared to a CuZSM5 catalyst.


Subject(s)
Copper/chemistry , Gasoline , Nitrogen Oxides/analysis , Nitrogen Oxides/chemistry , Phosphates/chemistry , Vehicle Emissions/analysis , Adsorption , Air Pollutants/analysis , Air Pollutants/chemistry , Ammonia/chemistry , Catalysis , Oxidation-Reduction , Porosity , Substrate Specificity , Sulfur Dioxide/chemistry , Temperature
13.
Chemosphere ; 59(6): 779-86, 2005 May.
Article in English | MEDLINE | ID: mdl-15811406

ABSTRACT

The potential of removing nickel and copper from industrial electroplating wastewaters by using mesoporous materials with MCM-41 type structure functionalised with different ratios of aminopropyl groups, namely Na50, Na25 and Na5, were evaluated. The synthesised solids sorbents obtained were characterised by X-ray diffraction, elemental chemical analysis and IR spectroscopy. In preliminary experiments, studies were carried out to determine the optimal experimental conditions for the retention of heavy ions. Effects of concentration, optimal pH, interference with humic substances and other metals were studied for Na5, which showed the best capacity of absorption determined by the corresponding isotherm. This material has a greater selectivity against sodium, indicating that ionic strength does not affect the extraction. Results of an application of this material to remove nickel and copper in synthetic and real industrial wastewater samples from an electrochemical industry area are shown with successful results. The lowest level of nickel and copper were observed when Na5 was used. This observation suggests that reactive aminopropyl-Si MCM-41 and similar materials may be a promising and provide for alternative environmental technologies in the future.


Subject(s)
Copper/isolation & purification , Nickel/isolation & purification , Silanes/chemistry , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Absorption , Copper/chemistry , Electroplating , Industrial Waste , Nickel/chemistry , Silanes/chemical synthesis , Waste Disposal, Fluid
14.
Arch. esp. urol. (Ed. impr.) ; 54(9): 997-1008, nov. 2001.
Article in Es | IBECS | ID: ibc-6237

ABSTRACT

OBJETIVOS: Analizar las características clínicas, diagnósticas y terapéuticas de la litiasis úrica en la actualidad. Papel del TAC helicoidal en el diagnóstico de la LEOC junto a la farmacología en la terapéutica. Valoración metabólica y cristalográfica del cálculo de ácido úrico. MÉTODOS: En la Unidad de Litiasis-Litotricia de la Fundación "Jiménez Díaz" se estima que la litiasis úrica representa el 5-7 por ciento. Se presenta en este trabajo un caso de litiasis coraliforme renal bilateral compleja de ácido úrico que pretende mostrar todas las posibilidades diagnósticas y terapéuticas donde el TAC helicoidal y la LEOC tienen su lugar. RESULTADOS: La ecografía, la uroradiología endoscópica han sido claves para el diagnóstico urológico de esta litiasis renal bilateral obstructiva radiotransparente. El cateterismo ureteral fue preceptivo ante la anuria por insuficiencia renal obstructiva bilateral. La litolisis complementada con LEOC consiguió hacer desaparecer la voluminosa litiasis de manera más rápida. CONCLUSIONES: La litiasis radiotransparente, fundamentalmente de ácido úrico precisa de exploraciones de diagnóstico que incluye la uroradiología y la endourología. A este diagnóstico urológico tradicional se añade el TAC helicoidal sin contraste para la litiasis ureteral sobretodo en situación de cólico renal. Si bien el tratamiento tradicional de la litiasis de ácido úrico ha sido la alcalinización urinaria (farmacológico), en aquellos casos de litiasis voluminosa, obstructiva, o ureteral en cólico renal, la LEOC acelera el proceso de resolución. El estudio integral del paciente que padece litiasis úrica para evitar la recidiva, incluye el análisis metabólico y cristalográfico (AU)


Subject(s)
Aged , Female , Humans , Kidney Calculi
SELECTION OF CITATIONS
SEARCH DETAIL
...