Search Results - temperature (decrease OR increase)
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24241
In search of cytotoxic selectivity on cancer cells with biogenically synthesized Ag/AgCl nanoparticles
Published 2022Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Green synthesis may be a useful approach to achieve selective cytotoxicity of silver nanoparticles on cancer cells and healthy cells. In this study, the concomitant biosynthesis of silver (Ag)/silver chloride (AgCl) nanoparticles from pineapple peel extracts and their behavior on the breast cancer cell line MCF-7 is shown. Bioreactions were monitored at different temperatures. Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), thermogravimetric analysis (TGA), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) techniques were used to characterize nanoparticle development. The breast cancer cell line MCF-7 was used as a test model to study the cytotoxic behavior of Ag/AgCl nanoparticles and, as a counterpart, the nanoparticles were also tested on mononuclear cells. Ag/AgCl nanoparticles with spherical and triangular morphology were obtained. The size of the nanoparticles (10–70 nm) and the size distribution depended on the reaction temperature. A dose close to 20 µg/mL of Ag/AgCl nanoparticles considerably decreased the cell viability of the MCF-7 line. The best cytotoxicity effects on cancer cells were obtained with nanoparticles at 60 and 80 °C where cell viability was reduced up to 80% at a concentration of 50 µg/mL. A significant preference was observed in the cytotoxic effect of Ag/AgCl nanoparticles against cancer cells in comparison to monocytes.Acceso al recurso -
24242
Dual modification of chayotextle starch: effect on physicochemical, functional, and structural properties
Published 2023Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Chemically modified starches are widely used as food additives to improve the appearance and physicochemical and biological properties of foods. The aim of this work is to chemically modify chayotextle (Sechium edule) starch by hydroxypropylation-crosslinking, and evaluate the effects of degree of substitution (DS), swelling power (SP), solubility index (SI), pasting, thermal properties, and morphological and molecular characteristics. Polar-Tex (modified maize starch) is used as control. The modified chayotextle starches (CHSs) exhibit a white color and DS values between 0.34% and 1.19% hydroxypropyl, dependening on propylene oxide concentration-response. In addition, the SP and pasting properties are higher in modified CHS than in native CHS and Polar-Tex. The SI and temperature of gelatinization of modified starches decrease compared to native sample. The morphology of native and modified CHS granules is spherical and oval. Fourier transform infrared and nuclear magnetic resonance studies confirm the structural modifications of CHS by hydroxypropylation-crosslinking. Dual-modified CHS can be potentially used as an additive in the food industry.Acceso al recurso -
24243
Fractal Geometric Analysis of the Goldbach Comet via the Fractal Correction Engine
Published 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
24244
Morphological composition and fiber partitioning along regrowth in elephant grass CT115 intended for ethanol production
Published 2020Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Leaf share, plant age and growth season are often overlooked as modifiers of the biomass quality in energy crops. The current work studied the effect of the given factors on the biomass yield and the biomass quality in Elephant grass CT115, intended for bioethanol production, in Veracruz, Mexico. Two seasons per year, 5 months each, were tracked on a 2-weeks basis. The climate is warm wet with summer rains, 1,142 mm of annual rainfall, and 26 °C monthly temperature. From day 56 of the wet season or from day 84 of the dry season, stems accumulated 12 or 6 Mg ha−1, respectively, while green leaves increased only 1 Mg. Higher biomass quality was recorded for the leaf fraction, or for the wet season regrowth. For instance, lignin contained in stems meant twice that of leaves, whereas stems recorded 20% less lignin in the wet season as compared to the dry season. Despite holocellulose being similar between fractions or seasons, hemicellulose and cellulose showed inverse correlation, while lignin and cellulose contents were directly correlated in stems. Increasing the annual harvest of green leaves will improve biomass quality, which is known to increase biodegradability and might improve the annual ethanol yield.Acceso al recurso -
24245
Physicochemical, thermal and rheological properties of three native corn starches
Published 2019Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Native starch was isolated from two corn landraces (blue and white) and a hybrid variety and then characterized for its physicochemical, thermal and rheological properties. The hybrid variety showed the highest starch yield, with its starch showing the highest fat, moisture and protein content but the lowest onset temperature of gelatinization. The hybrid corn starch also showed the highest G’ and G” values. The tested starches showed similar Tp, Tc, and ΔH values. The amylose contents ranged from 21.5 to 22.4%, with starch from blue corn showing the highest amylose content. All starches were white, with L values ranging from 93.6 to 99.5. The light absorbance of the starch gels increased with storage time. The obtained results demonstrated that the physicochemical, thermal and rheological properties of corn starch are highly dependent on the corn type.Acceso al recurso -
24246
Morphological, barrier, and mechanical properties of banana starch films reinforced with cellulose nanoparticles from plantain rachis
Published 2021Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: The main aim of the present study was to characterize banana starch films reinforced with nanoparticles from plantain rachis. Nanoparticles were obtained by acid hydrolysis and sonication, exhibiting a mean hydraulic diameter of about 60 nm. Scanning electron microscopy micrographs showed that the nanoparticle thickness ranged between 9.8 and 22.3 nm. The thermal gravimetric analysis showed that nanoparticles are thermally stable for temperatures up to 340 °C. Films were made for different fractions of nanoparticles (0.0, 1.75, 2.5, and 4.0%) relative to total solids, and glycerol was used as a plasticizer. The influence of the addition of nanoparticles to starch films on the morphology, water vapor permeability (WVP), and mechanical properties of the nanocomposites films was explored. Cellulose nanoparticles reduced the WVP, and increased the tensile strength and flexibility of the starch films. FTIR analysis of films was used to show that nanoparticles improved the molecular organization of starch chains. It was proposed that nanoparticles acted as a crosslinked for starch chains via hydrogen bonding effects.Acceso al recurso -
24247
Magnesium Glycinate
Published 2025Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
24248
Effect of Co content on electrochemical hydrogen kinetics properties of single-phase BCC-type MgAlTiCoxNi high entropy alloys used as a negative electrode in basic and acidic elect...
Published 2024Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: In this report, the effect of Co content on the electrochemical hydrogen storage reaction kinetic of MgAlTiCoₓNi (x = 1, 1.5 and 2) High Entropy Alloys (HEAs) as negative electrodes under basic (6 M KOH) and acidic (1 M H₂SO₄) electrolyte was studied. Empirical thermodynamic parameters were used to predict the formation of HEAs. The alloys were obtained after 8 h of high-energy ball-milling. The structural analysis showed the formation of a BCC structure and a reduction of the unit lattice with increasing Co content. At high temperatures, the structure changes from BCC-type to B2-type. The morphology and surface area of the MgAlTiCoNi, MgAlTiCo₁.₅Ni, and MgAlTiCo₂Ni alloy powders are very similar. Electrochemical measurements show that alloys exposed to acidic solutions as negative electrodes exhibit higher discharge capacity and better electrochemical hydrogen storage kinetics properties. The increase in Co content in the alloys in both basic and acidic solutions reduced the discharge capacity. Furthermore, a high Co content in the electrodes exposed to an acidic electrolyte reduces the anticorrosion properties of the alloy. The MgAlTiCoNi HEA electrode achieved the best electrochemical performance with a discharge capacity of 465 mAh/g in an acidic electrolyte after a short galvanic charge (60 min). The concentration of Co in the HEAs revealed a direct relationship with the hydrogen diffusion rate, while the lattice parameter is associated with the discharge capacity.Acceso al recurso -
24249
Keratin modified and functionalized as a reinforcement and nucleation agent of β-polypropylene composites
Published 2022Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: A new green β nucleating agent has been obtained from industrial waste. This way, pimelic acid (PA) was chemically supported on treated keratin fibers to promote the β polymorph into a polypropylene matrix using several percentages of reinforcement (0.5, 1.0, and 5.0% w/w). IR spectra suggest a successful functionalization showing the presence of a new band at 1571 cm−1, indicating a bond between PA and the keratin surface. According to the scanning electron spectroscopy, the nucleating agent was homogeneously distributed on the keratin surface. Wide angle X-ray diffraction (WAXD) patterns and differential scanning calorimetry (DSC) curves demonstrate that the functionalized keratin fibers were able to promote a high percentage of β-crystal into the polypropylene matrix (79% and 60%, respectively). The thermomechanical properties were characterized by dynamic mechanical analysis (DMA). At −30°C, the new reinforcement provides an important increase of 25% in the storage modulus compared with the raw polypropylene. The new reinforcement seems to strongly influence the mobility of the amorphous phase, shifting the Tg to higher temperatures.Acceso al recurso -
24250
Defect states and morphological evolution in mechanically processed ZnO + xC nanosystems as studied by EPR and photoluminescence spectroscopy
Published 2016Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: An evolution of electron paramagnetic resonance (EPR) and photoluminescence (PL) spectra of various active states (hydrogen donor DH EPR centers, Zn vacancy-related EPR centers , EPR DS centers from shallow donors (g = 1.9640) in ZnOW, Mn2+ ions in ZnOZB, C EPR centers in carbon nanoparticles, forming the near-band-edge (NBE) PL emission, PL emission typical for Zn-, O- and N-enriched ZnOW particles, as well as oxidized carbon nanodots (OCN)) was observed in the mixtures of ZnO + xC nanoparticles during prolonged high-energy mechanical processing (MP) in a hermetically sealed grinding chamber. The results of EPR and PL spectroscopy, X-ray diffraction analysis, as well as morphological analysis by means of atomic force microscopy (AFM) and laser particle sizer (LPS) measurements show a wide variety of interrelated series–parallel processes in the samples with increasing MP processing time (tMP). These processes include: (a) dramatic reduction in intensity of the DH EPR signal and PL bands at 3.14 (1.57), 2.53 and 2.3 eV during the first minutes of MP, which correlate with sample disaggregation; (b) grinding of ZnO particles and formation of Zn vacancy-related EPR centers in the area of destruction (AD); (c) an increase in sample temperature; (d) annealing of the Zn vacancy-related EPR centers formed; (e) initiation of carbon nanoparticle interaction with oxygen in the grinding chamber; (f) formation and growth of the EPR signal due to carbon nanoparticles; (g) formation of a reducing environment in the grinding chamber; (h) stabilization of donor DS-centers in AD of ZnO nanoparticles; (i) an increase in CO concentration in the grinding chamber; (j) inhibition of DS paramagnetic centers in ZnO; (k) initiation of the EPR signals due to Mn2+ ions in ZnOZB sphalerite phase in the sample with the lowest carbon content; (l) inhibition of nitrogen PL centers in ZnO; (m) the formation of oxidized carbon nanodots (OCN) showing a PL band at 2.8 eV. A detailed analysis for the localization of EPR and PL centers in the MP samples is presented.Acceso al recurso -
24251
Growth, yield, fiber content and lodging resistance in eight varieties of Cenchrus purpureus (Schumach.) Morrone intended as energy crop
Published 2016Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Growth, biomass yield, fiber content and lodging resistance were studied, during a six month growth period, for eight varieties of Cenchrus purpureus, intended as energy crop, in Veracruz, Mexico. Then, only yield at day 182 was assessed for two additional years. The varieties were: CT115 (CT), African Cane (AC), Taiwan (TAI), King Grass (KG), Vruckwona (VRU), Roxo (RX), OM22 (OM) and Cameroon (CAM). Local weather is warm and sub-humid, historical data for monthly average temperature and annual rainfall were 25.8 °C and 1142 mm, respectively. Height, diameter and light interception were measured monthly from day 65–185. At day 185, biomass yield and tiller density were measured. Number of lying tillers was counted to estimate lodging resistance. Cellulose and hemicellulose content were estimated in leaf and stem. No differences were found for dry matter yield or stem yield at day 185 in the first year. Regarding the next two years, TAI yielded above CT, OM or ROX. Average dry matter yield was higher in the second year than in the establishment cycle (38.6 vs 21.1 Mg ha−1), but decreased in the third year (32.2 Mg ha−1). In both stem and whole plant, AC and KG showed higher hemicellulose content than RX, OM or CT; while AC and VRU had higher cellulose than RX in stem, or than CT in the whole plant. Furthermore, varieties AC, KG, VRU and TAI were resistant to lodging and had a higher fiber content, so they are recommended as energetic crops.Acceso al recurso -
24252
The Nexus Framework: Recursive Harmonic Genesis and the Digital Substrate of Reality
Published 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
24253
The Nexus Recursive Harmonic Architecture: Comprehensive Remediation and Technical Specification
Published 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
24254
The Logical Reality of SHA-256 Reversibility: A Comprehensive Analysis via Dual-Wave Theory and the Twin Prime Policy Constraint
Published 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
24255
Global Guardian Initiative: An Integrated AI-Powered Protection System for Vulnerable Animals
Published 2025Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
24256
MH370: Mathematical Proof of the Survival of All Passengers Within a Tensorial Capsule at Broken Ridge and a Depth of 4650 Meters in the Southern Indian Ocean, at Coordinates Longi...
Published 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
24257
MH370: Mathematical Proof of the Survival of All Passengers Within a Tensorial Capsule at Broken Ridge and a Depth of 4650 Meters in the Southern Indian Ocean, at Coordinates Longi...
Published 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
24258
Sylvicanthon Halffter & Martinez 1977
Published 2018Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
24259
The Sun is not a Burning Atomic Furnace; rather, it functions as the Central Processing Unit (CPU) for the entire solar system, operating upon the bedrock of absolute zero (2.73 Ke...
Published 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
24260
Hamzah Military Radar-Tensor: No Movement Will Remain Hidden; From The Relocation of a Nuclear Submarine in the Depths of The Ocean to the Launch of a Ballistic Missile On the othe...
Published 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso