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1.
Data Brief ; 45: 108631, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36426091

RESUMO

Silver nanoparticles (AgNP) are important materials in developing novel devices owing to their unique physical and chemical properties. It attracted much interest because it exhibits a prominent Surface Plasmon Resonance (SPR) property that is dependent on its nanodimension and nanostructure. Its green synthesis using biological extracts offers a cheap and benign process to afford AgNPs. However, natural extracts contain thousands of metabolites that affect the formation of the desired AgNP. Other factors such as temperature, pH, time, and volume also influence the formation of the nanometal hence, optimization is always carried out to afford sufficient amounts of the nanometals. To eliminate further trials and errors, this work reports the optimization of AgNP using the aqueous extract from Laxitextum bicolor, a wild type of mushroom from the family of Stereacea. Using central composite design (CCD) under Response Surface Methodology (RSM), five levels from each of the five independent parameters (pH, temperature, time, volume of extract, and volume of AgNO3) in a single-block mode afforded 32 experimental runs where SPR at 420 nm of the formed AgNP was measured as the dependent variable. ANOVA evaluation revealed that the p-value of the refined model is significant (p-value = 0.00) and the p-value of lack-of-fit is insignificant (LoF = 0.223). Model statistics displayed acceptable goodness of fit (R2 = 98.54%, adjusted R2 = 97.34, predicted R2 = 92.50%). The predicted optimal condition to synthesize AgNP from aqueous extract of L. bicolor were determined to be pH = 10, Temperature = 55 °C, Time = 180 min, Vol. Ext = 1.5 mL, and Vol. AgNO3 = 20 mL. To check the accuracy and repeatability of predicted optimal synthesis conditions, the UV-Vis analysis was employed. It showed that the peak intensity has a narrow peak with an absorbance of 3.40 at around 420 nm, which was the set criteria for choosing the optimal synthesis condition.

2.
Data Brief ; 42: 108219, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35539027

RESUMO

The upsurge of antibiotic usage in the 20th century has resulted in increasing levels of pharmaceutical compounds in bodies of water. A particular antibiotic, levofloxacin, is a third-generation quinolone known to target Gram-positive organisms like atypical pathogens. Chronic toxic effects of levofloxacin to some microorganisms lead to the disruption of marine ecosystems. Unfortunately, a relatively low concentration of levofloxacin in water bodies discourages researchers from exploring potential risk assessment and removal in wastewater treatment plants. In this article, aqueous levofloxacin was degraded using hydroxyapatite catalyst under UV-irradiation. Response Surface Methodology (Box Behnken Model) was used to model and optimize the degradation efficiency parameter. The response was fitted into a 2-factor interaction equation revealing a satisfactory ANOVA evaluation (R2=97.08%, adjusted R2= 94.89, predicted R2=91.1%). An optimal photodegradation efficiency was determined to attain the following conditions: 1.5 g/L catalyst dose, 4 ppm levofloxacin, and a pH level of 10. The model predicted a value of 71.6% degradation efficiency, which is very close to 70.6% generated experimentally.

3.
Ultrason Sonochem ; 73: 105540, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33812249

RESUMO

Degradation of polysaccharides to afford low-molecular-weight oligosaccharides have been shown to produce new bioactivities that are not present in the starting material. The simplicity of ultrasonic treatment in the degradation of a polysaccharide, such as κ-carrageenan, offers practical advantage in producing degraded products with lower molecular weight that may have new interesting potential activities. This study embarked on investigating the effects in molecular weights and structural changes of κ-carrageenan under varying ultrasonic conditions. Molecular weight (MW) monitoring of ultrasonically-treated κ-carrageenan at various conditions were done by gel permeation chromatography. The product formed using the optimized condition was characterized using FTIR and NMR. The decrease in MW has been shown to be dependent on low concentration (5.0 mg mL-1), high amplitude (85%), and long treatment time (180 mins) to afford a degraded κ-carrageenan with average molecular weight (AMW) of 41,864 Da, which is a 96.33% reduction from the raw sample with initial AMW of 1,139,927 Da. Structural analysis reveals that most of the peaks of the raw κ-carrageenan was retained with minor change. 1D and 2D NMR analyses showed that the sonic process afforded a product where the sulfate group at the G4S-4 position was cleaved forming a methylene in the G4S ring. The results would be useful in the structure-activity relationship of κ-carrageenan oligosaccharides and in understanding the effect in the various potential applications of degraded κ-carrageenan.


Assuntos
Carragenina/química , Sonicação/métodos , Cromatografia em Gel , Estrutura Molecular , Peso Molecular , Polimerização , Análise Espectral/métodos
4.
Asian Pac J Cancer Prev ; 22(1): 53-60, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33507679

RESUMO

BACKGROUND: The genus Aglaia (Meliaceae) is an established source of many anticancer compounds. The study evaluated the leaf extracts of Aglaia loheri, a tree native to the Philippines, as potential source of anticancer compounds. METHODS: Using bioassay-guided fractionation, A. loheri leaf extract was subjected to various chromatographic techniques and step-wise application of MTT assay on human colorectal carcinoma cells, HCT116, to determine the cytotoxic fractions. The most cytotoxic HPLC isolate was structurally identified using 1D and 2D NMR and its apoptotic effect was assessed by JC-1 staining, caspase 3/7 assay and TUNEL assay. RESULTS: After stepwise chromatography fractionation, an HPLC isolate, structurally identified as aglaforbesin derivative (AFD), demonstrated potent cytotoxicity against HCT116. AFD exhibited strong toxicity (IC50 = 1.13 ±0.07 µg/mL) and high selectivity on HCT116 than normal human kidney cells (HK-2). AFD-induced toxicity to HCT116 is possibly through the stimulation of the apoptotic signaling pathway via caspase 3/7 activation and DNA fragmentation independent of mitochondrial membrane depolarization. CONCLUSION: AFD exhibited selective cytotoxicity and apoptotic activity to HCT116 and could be further developed as anticancer drug lead.


Assuntos
Aglaia/química , Antineoplásicos Fitogênicos/farmacologia , Apoptose , Neoplasias Colorretais/patologia , Mitocôndrias/patologia , Extratos Vegetais/farmacologia , Proliferação de Células , Neoplasias Colorretais/tratamento farmacológico , Humanos , Mitocôndrias/efeitos dos fármacos , Células Tumorais Cultivadas
5.
RSC Adv ; 11(52): 32873-32883, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-35493555

RESUMO

Bacterial cellulose (BC) is a promising material for new technologies, but the range of application is limited due to its hydrophilicity. This work aims to design a hydrophobic material derived from BC, which may find use in a broad range of applications such as packaging, sensing, construction, and electronics. We report that ultrasonic treatment of BC increased the degree of material impregnation into the fiber network that altered the hydrophobic properties of the BC-based composite films. Measurements in XTM revealed that sonication enhanced the porosity of BC films from 5.77% to 22.54%. Materials such as magnesium hydroxide (MH), graphene oxide (GO), and stearic acid (SA) were impregnated into the BC films. FTIR analysis and SEM-EDS confirmed the absorption of these molecules into the BC fibers. The water contact angle (WCA) of BC films impregnated with these functional materials showed a three to four-fold increase in hydrophobicity. The incorporation of 0.3% GO in sonicated BC afforded WCA at 137.20°, which is way better than the commercial water repellant (114.90°). The sonicated BC film afforded better tensile strength and Young's modulus, up to 229.67 MPa and 6.85 GPa, respectively. This work has shown that ultrasonic treatment improved the absorption capability of BC towards hydrophobic functionalization.

6.
Food Chem ; 335: 127629, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32736156

RESUMO

Folate deficiencies are prevalent in countries with insufficient food diversity. Rice fortification is seen as a viable way to improve the daily intake of folates. This work reports an efficient process of rice fortification involving ultrasonic treatment and absorption of the folic acid fortificant. Increased porosity due to sonication allowed the efficient absorption of folic acid into the brown rice kernel up to 5.195 × 104 µg/100 g, a 1,982-fold increase from its inherent content. The absorbed folic acid in brown rice has 93.53% retention after washing and cooking. Fortification of ultrasound-treated milled rice with folic acid was also efficient affording 6.559 × 104 µg/100 g, a 4,054-fold increase from its basal content. The effect of fortification caused a decrease in the thermal and pasting temperatures. The fortification also caused yellow coloration, decrease in hardness, and increase in the adhesiveness of the rice. The resulting fortified brown rice showed improved textural properties favorable for consumers.


Assuntos
Absorção Fisico-Química , Ácido Fólico/química , Alimentos Fortificados/análise , Oryza/química , Ondas Ultrassônicas , Adesividade , Cor , Dureza
7.
Ultrason Sonochem ; 71: 105383, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33227580

RESUMO

As a green, nonthermal, and innovative technology, ultrasonication generates acoustic cavitation in an aqueous medium, developing physical forces that affect the starch chemistry and rice grain characteristics. This review describes the current information on the effect of ultrasonication on the morphological, textural, and physicochemical properties of rice starch and grain. In a biphasic system, ultrasonication introduced fissures and cracks, which facilitated higher uptake of water and altered the rice starch characteristics impacting textural properties. In wholegrain rice, ultrasonic treatment stimulated the production of health-related metabolites, facilitated the higher uptake of micronutrient fortificants, and enhanced the palatability by softening the rice texture. This review provides insights into the future direction on the utilization of ultrasonication for the applications towards the improvement of rice functional properties.


Assuntos
Fenômenos Químicos , Manipulação de Alimentos/métodos , Oryza/química , Sonicação , Amido/química
8.
Data Brief ; 32: 106198, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32904351

RESUMO

The data included in this article are related to research paper entitled "Efficient fortification of folic acid in rice through ultrasonic treatment and absorption". These datasets compile the folic acid uptake expressed in concentration and the effects of folic acid fortification on the physical properties of brown and milled rice. We reported the folic acid uptake of rice in increasing fortificant concentration through soaking, one-step, and stepwise fortification protocols. In addition, the data on the effects of fortification on the color, pasting, and textural properties of brown and milled rice were also presented.

9.
Ultrason Sonochem ; 68: 105234, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32593147

RESUMO

This work investigates the effect of sonication on brown and milled rice grains of both waxy and non-waxy varieties. We report herein the microstructural analysis of uncooked rice kernels under sonication and its effect on the textural properties. X-ray computed tomography results showed the formation of microporous surfaces and the creation of cracks and fissures. Sonication increased the % porosity of the rice samples allowing for easy penetration of water during the cooking process and promotes softer texture. Moreover, the effect of sonication in brown rice resulted to the decrease in endogenous iron and phosphorus contents but increased its capacity for iron uptake through fortification when sonicated rice is soaked in the mineral solution.


Assuntos
Nutrientes/análise , Oryza/química , Sonicação , Absorção Fisico-Química , Culinária , Dureza , Ferro/química , Porosidade , Reologia
10.
Food Res Int ; 119: 15-22, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30884643

RESUMO

Folic acid (FA) is an essential micronutrient but its delivery and bioavailability is a problem due to its inherent instability at various conditions. A robust protective encapsulation system for folic acid is highly desirable. This work reports the use of the divalent copper in complex with alginate as a strong encapsulation system for folic acid. Using gel spherification technique, hydrogels were formed upon dropwise addition of sodium alginate solution in a copper bath. In the presence of folic acid, encapsulation was achieved as evidenced by the yellow coloration, intact surface morphology (SEM), the presence of nitrogen (23.08% N; EDX), and thermal gravimetric degradation for folic acid (28% FA; TGA). The spherical hydrogels do not burst upon 2 m-drop test and remain intact at pH 1.2 with no evident release of folic acid indicating stability of the encapsulation system at the abdominal gastric condition. The copper alginate acted as gastro-resistant material and slow release of folic acid occurs only at pH > 5 especially at simulated intestinal conditions (pH 8.2). The study indicates the potential of copper alginates as a protective encapsulant to ensure stability and slow release of FA in simulated physiological pH conditions.


Assuntos
Alginatos/química , Ácido Fólico/química , Hidrogéis/química , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio
11.
Carbohydr Polym ; 169: 315-323, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-28504150

RESUMO

Cellulose nanocrystals (CNCs) are promising materials that are readily extracted from plants and other cellulose-containing organisms. In this study, CNCs were isolated from freshwater green algae (Cladophora rupestris) thriving in a volcanic lake, using hydrobromic acid (HBr) hydrolysis. Morphological and structural studies revealed highly crystalline CNCs (94.0% crystallinity index) with preferred orientation to [100] lattice plane as shown by XRD measurements and have an average diameter of 20.0 (±4.4)nm as shown by TEM. Thermal studies showed increased temperature for thermal decomposition of CNCs (381.6°C), which is a result of HBr hydrolysis for CNCs isolation. The isolated CNCs were reinforced into starch based biocomposites via solution casting and evaporation method. Mechanical strength was improved as high as 78% upon addition of 1% cellulose nanocrystals in the films. The produced films are promising materials for their high mechanical strength, biodegradability and availability of raw materials.


Assuntos
Celulose/química , Clorófitas/química , Nanopartículas/química , Amido , Água Doce
12.
Chem Commun (Camb) ; 46(42): 7879-93, 2010 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-20852778

RESUMO

The innovation of polyolefin with unique architecture, composition and topology continues to inspire polymer chemists. An exciting recent direction in the polyolefin field is the design of new catalysts based on late-transition metals. In this review, we highlight recent developments in rationally designing late-transition metal catalysts for olefin polymerization. The examples described in this review showcase the power of the design of well-defined late-metal catalysts for tailored polyolefin synthesis, which may usher in a new era in the polymer industry.

15.
Org Lett ; 6(6): 865-8, 2004 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-15012051

RESUMO

[structure: see text] Herein we describe an efficient synthesis of cyclophanes comprised of intra-annular nitrogen functional groups through a template-promoted cyclization by ring-closing metathesis (RCM). The synthesis proceeds through condensation of meta-styryl anilines with acenaphthenequinone to form the templates, followed by RCM with Grubb's second-generation catalyst to afford cyclophanes with internal alpha-diimine functionality. Prolonged hydrogenation efficiently removes the template to provide a macrocycle containing the diamine functionality.

16.
J Am Chem Soc ; 124(6): 924-5, 2002 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-11829598

RESUMO

Conjugated diynes undergo dimerization in the presence of acetic acid and catalytic amounts of Pd(PPh3)4. The unprecedented reaction gives a novel chromophore containing the (E)-1,2-divinyl-1.2-diethynylethene (DVDEE) module, which is a potentially viable building block for acetylenic scaffolding.

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