Miracle-dz/UniFAR-FTUs huggingface dataset:
NIXTAMALIZATION IN TWO STEPS WITH DIFFERENT CALCIUM SALTS AND THE RELATIONSHIP WITH CHEMICAL, TEXTURE AND THERMAL PROPERTIES IN MASA AND TORTILLA

ABSTRACT The present investigation evaluated the chemical and thermal properties using lime and alternative calcium salts, and their effect on the characteristics of masa and tortilla obtained in a two-step nixtamalization process. White dent corn was cooked in calcium hydroxide solution (1.2% [w/v]; 1:3 maize : water ratio) at 80C (30 min), and the calcium hydroxide was replaced either by calcium chloride or lactate at calcium equilibrated concentration (30 min), and steeped in a cooking solution for 2,400 min. Grains were analyzed for water and calcium absorption, and apparent diffusion coefficients were calculated. Thermal properties of flour made from these grains were also determined. Additionally, the masa and tortilla made with nixtamalized corn flours were analyzed for texture and color, and an acceptability test was performed on the tortilla. Water absorption showed a notable increase during cooking, approaching an asymptotic maximum absorption after 8 h of steeping for all treatments. The maximum calcium absorption was obtained in stepwise nixtamalization with solutes of CaCl2 and C6H10O6Ca. The water apparent diffusion coefficients were adequately described by Fick's model and it was found that C6H10O6Ca showed the highest value (5.5901 × 10−10 m2/s), while that for calcium diffusion the model gave low fits. The thermal analysis showed that gelatinization temperatures were affected significantly (P < 0.05) by the cooking and steeping times, while the gelatinization range and enthalpy were affected significantly (P < 0.05) by salt type. The masas and tortillas obtained from all treatments presented good texture and color characteristics in comparison with the commercial flour. Sensory analysis showed that the tortilla nixtamalized with C6H10O6Ca was the most acceptable to consumers. PRACTICAL APPLICATIONS The main contribution of the present study is the utilization of different salts as an alternative to calcium during cooking and steeping in a two-phase nixtamalization process. The different calcium salts provide an option to avoid undesirable changes in the products' quality characteristics present in the typical nixtamalization process produced by high lime concentration. At the same time, these alternatives could contribute to reduced environmental pollution, specifically in the waste water (decreased pH and the solids). A prediction model for water and calcium absorption during the nixtamalization process is proposed for the different calcium salts. The physical, chemical and thermal changes that occur in the nixtamalization in the different treatments for the different calcium salts were related to color and texture characteristics of masa and tortilla as well as tortilla acceptability.
Gas Chromatographic Analysis of Flavor in Processed Milks

Summary A simple solvent extraction technique for recovering flavor components, with the exclusion of fat, from processed milks was devised. Analysis of the flavor extracts by gas chromatography showed significant differences among products and between individual samples of a product. When highly purified hexane was used as the extracting solvent, products could be examined organoleptically before and after extraction for flavor differences. Chromatograms for evaporated and dried whole milks indicated the presence of δ -deca- and δ -dodecalactone as prominent components. Small peaks corresponding to these lactones could be seen on chromatograms for pasteurized, homogenized milk but not for raw milk. The procedure of flavor analysis seems appropriate for testing the relative susceptibility of milk supplies to flavor defects. It should also aid in product development work and in reduction of taste panel effort.
Longitudinal dispersion in laboratory and natural streams

This study concerns the longitudinal dispersion of fluid particles which are initially distributed uninformly over one cross section of a uniform, steady, turbulent open channel flow. The primary focus is on developing a method to predict the rate of dispersion in a natural stream. Taylor's method of determining a dispersion coefficient, previously applied to flow in pipes and two-dimensional open channels, is extended to a class of three-dimensional flows which have large width-to-depth ratios, and in which the velocity varies continuously with lateral cross-sectional position. Most natural streams are included. The dispersion coefficient for a natural stream may be predicted from measurements of the channel cross-sectional geometry, the cross-sectional distribution of velocity, and the overall channel shear velocity. Tracer experiments are not required. Large values of the dimensionless dispersion coefficient D/rU* are explained by lateral variations in downstream velocity. In effect, the characteristic length of the cross section is shown to be proportional to the width, rather than the hydraulic radius. The dimensionless dispersion coefficient depends approximately on the square of the width to depth ratio. A numerical program is given which is capable of generating the entire dispersion pattern downstream from an instantaneous point or plane source of pollutant. The program is verified by the theory for two-dimensional flow, and gives results in good agreement with laboratory and field experiments. Both laboratory and field experiments are described. Twenty-one laboratory experiments were conducted: thirteen in two-dimensional flows, over both smooth and roughened bottoms; and eight in three-dimensional flows, formed by adding extreme side roughness to produce lateral velocity variations. Four field experiments were conducted in the Green-Duwamish River, Washington. Both laboratory and flume experiments prove that in three-dimensional flow the dominant mechanism for dispersion is lateral velocity variation. For instance, in one laboratory experiment the dimensionless dispersion coefficient D/rU* (where r is the hydraulic radius and U* the shear velocity) was increased by a factory of ten by roughening the channel banks. In three-dimensional laboratory flow, D/rU* varied from 190 to 640, a typical range for natural streams. For each experiment, the measured dispersion coefficient agreed with that predicted by the extension of Taylor's analysis within a maximum error of 15%. For the Green-Duwamish River, the average experimentally measured dispersion coefficient was within 5% of the prediction.
Lithium-ion conduction in complex hydrides LiAlH4 and Li3AlH6

Lithium-ion conduction in complex hydrides LiAlH4 and Li3AlH6 was investigated using ac complex impedance measurements. The conductivities at room temperature were 8.7×10−9 S/cm in the case of LiAlH4 and 1.4×10−7 S/cm in the case of Li3AlH6. To enhance the conductivity of Li3AlH6 having good thermal stability in heating/cooling cycles, mechanical milling, and addition of lithium halides (LiCl, LiI) were implemented. The maximum value of 2.5×10−4 S/cm at 393 K was observed when 0.33 M ratio of LiI was added to Li3AlH6. This study demonstrated two research directions to enhance the lithium-ion conductivity in a variety of complex hydrides.
Mineral phases of the Earth´s mantle

Abstract Our knowledge of the structure of the Earth´s interior has been obtained by analysing seismic waves that travel in the Earth, and the reference Earth global models used by geophysicists are essentially seismological. Depth profiles of the seismic waves velocities reveal that the deep Earth is divided in several shells, separated by velocity and density discontinuities. The main discontinuity located at a depth of 2900 km corresponds to the transition between the mantle and the core. The Earth´s mantle can be further divided into the upper mantle and the lower mantle, with a transition zone characterised by two prominent increases in velocities observed at 410- and 660-km depths. This article will be focused on the mineral phases of the Earth´s mantle. The interpretation of seismological models in terms of chemical composition and temperature relies on the knowledge of the nature, structure and elastic properties of the candidate materials. We will describe to what extent recent advances in experimental mineral physics and X-ray diffraction have yielded essential knowledge on the structure and high-pressure high-temperature behaviour of pertinent materials, and major improvements in our understanding of the chemical and mineralogical composition of the Earth´s mantle.
Reversible Addition–Fragmentation Chain Transfer Polymerization of Vinyl Acetate in Bulk and Suspension Systems

Suspension and bulk polymerizations of vinyl acetate (VAc) are performed in several experimental conditions, using cyanomethyl methyl(phenyl) carbamodithioate as the chain transfer agent (CTA). The polymerization kinetics are monitored in batch for bulk polymerizations, showing an inhibitory period at the beginning of the reaction runs, despite the particular experimental conditions used. More accurate control over the molecular properties of the synthesized poly(vinyl acetate) (PVAc) is achieved when high concentrations of CTA are used. Similar experimental conditions are applied to prepare PVAc particles via suspension polymerization of VAc in the presence of small amounts of CTA. It is possible to produce spherical particles with a narrow particle size distribution and predominant spherical morphology. Although the reactions yield low control over the molecular weight properties, it is possible to use the synthesized particles as macro-CTAs and promote chain extension reactions to extend the chain length of the PVAc.
The Induction Period in Chain Reactions

The conditions for the establishment of a stationary state in a system of consecutive reactions can be investigated quantitatively in a sufficient number of cases to permit precise criteria to be formulated generally for the length of the induction period (i.e., prestationary state period) in chain reactions. These are given as functions of the individual rate constants for the separate reactions, the extent of the reaction and the percent of stationary state concentrations achieved. Such relations provide a means for the evaluation of the self‐consistency of experimental data with proposed mechanisms and also provide numerical limits on the values of individual rate constants.Various chain reactions are examined in the light of these criteria. Of the hydrogen‐halogen reactions, the H2–Cl2 reaction mechanism does not fulfill the stationary state requirements, and it is probable that many of the discordant results found in this reaction arise from this difficulty.
Polar and nonpolar GaN quantum dots

Growth, structural and optical properties of GaN quantum dots are reviewed, with a special emphasis on plasma-assisted molecular beam epitaxy. The versatility of this technique makes it particularly adapted to growth of quantum dots, either polar (c-plane) or nonpolar (a-plane and m-plane). After describing in detail the growth process and analyzing the morphology of the dots, we review the optical properties of these nanostructures and discuss the properties of single dots.
Structural characteristics of pyrochlore formation

By calculating the value of the unknown oxygen positional parameter x for a large number of A3+2B4+2O7 pyrochlores, it was determined that increasing the radius of the A cation in a series of constant B increased the value of x, and that increasing the radius of the B cation in a series of constant A decreased the value of x. The region of pyrochlore formation has a range of x values from 0.404 to 0.432 and contains BO6 polyhedra that closely approach Oh symmetry and AO8 polyhedra that are highly deformed. It was shown that the characteristics of the BO6 polyhedra were the most important in determining whether or not a pyrochlore would form.
Sensory interaction between 3-mercaptohexan-1-ol and 2-isobutyl-3-methoxypyrazine in dearomatised Sauvignon Blanc wine

Background and Aims Two compounds that play an important role in the aroma of Sauvignon Blanc wines are 3-mercaptohexan-1-ol (3MH) and 2-isobutyl-3-methoxypyrazine (IBMP). Little is known about the sensory interaction of these two compounds in Sauvignon Blanc wine and which aroma attributes they elicit at the concentration range normally found in Sauvignon Blanc wines. Methods and Results 3-Mercaptohexan-1-ol and IBMP were spiked separately or as a mixture to dearomatised Sauvignon Blanc wine at five different concentrations normally occurring in wine, and were assessed by a trained sensory panel. Descriptors were generated by the panel for these compounds when added alone, with overall tropical, guava and passionfruit being generated for 3MH, while overall green, green pepper and grass were used for IBMP. The contribution of these attributes differed, however, depending on the concentration of 3MH and IBMP. Conclusions There is sensory interaction between 3MH and IBMP. The sensory attributes linked to each compound can depend on the concentration of both compounds present in wine. It is possible that wine producers may use this phenomenon to achieve a specific style of Sauvignon Blanc wine. Significance of the Study This study might allow wine producers to predict which aroma profile to expect when 3MH and IBMP occur at a certain concentration in Sauvignon Blanc wine.
Shoot Topping and Ethephon Effects on White Riesling Grapes and Grapevines

Canopy modification by shoot topping or ethephon application was examined with pendelbogen -trained White Riesling grapevines in the hot, humid Piedmont region of Virginia. Treatments were: control, two levels of shoot topping (10 vs. 20 leaves per shoot retained) or ethephon application to shoot tips (600 mg/L). Topping shoots to maintain 10 or 20 leaves per shoot reduced annual cane pruning weights by an average of 61% or 24%, respectively, compared with non-topped vines. The application of ethephon produced a vine size comparable to that of vines hedged to 20 leaves per shoot. Canopy insolation was least with control vines (due to shoot tops shading original canopy) and similar among other treatments. Vines topped to 20 leaves per shoot produced more fruit than did vines topped to 10 leaves per shoot. More fruit was harvested from shoot-topped vines than from control vines in two of three years. Neither wood maturity nor dormant bud survival were adversely affected by shoot topping or ethephon application. Greatest fruit soluble solids at harvest were generally observed with vines topped to 20 leaves per shoot. Shoot topping resulted in fruit with lower titratable acidity at harvest than with control vines, but fruit pH was not appreciably affected by any treatment. Fruit rot incidence and the concentrations of rot-associated metabolites (glycerol, ethanol, and acetic acid) were significantly and mutually correlated. Fruit rot and rot metabolites were greatest with control and ethephon-treated vines and were least with vines whose shoots were topped to 10 leaves. Shoot topping to 15 to 20 leaves per shoot appears appropriate with vigorous, low-trained White Riesling to maximize benefits of this remedial canopy management practice in the humid mid-Atlantic United States.
Effect of Two Nitrogen Forms on the Growth and Iron Nutrition of Pea Cultivated in Presence of Bicarbonate

ABSTRACT Two cultivars of pea: ‘PS210713’ (‘PS’), sensitive to iron deficiency, and ‘Marveille de Kelvedon’ (‘MK’), tolerant, were cultivated in controlled climatic conditions during one month, on a nutrient solution containing either nitrate (NO3 −, 4 mM) or ammonium (NH4 +, 4 mM) and in the presence of bicarbonate (10 mM). The effects of these nitrogen forms on the growth and the mineral nutrition, and especially iron nutrition are analyzed. The reduction of growth by bicarbonate was approximately 30% in case of NO3 − nutrition in the two cultivars, whereas in ammoniacal treatment the reduction is only 6% and 18% respectively in ‘PS’ and ‘MK’ cultivars. In presence of bicarbonate, the plant growth is not stimulated by NO3 −relatively to its growth on ammoniacal medium, as often noticed when plants are cultivated on medium without bicarbonate: In presence of this compound, the biomass production of plant pea, was not influenced by the nitrogen forms. The nitric source led to a ferric chlorosis in the sensitive cultivar plants whereas any chlorosis was noted when ammoniacal source was applied. On the other hand, nitric nitrogen form decreased the nitrogen feeding of plants and increased the potassium one, while the effect of the ammoniacal nitrogen form on these nutrients was quite the inverse. In addition, the later increased the allocation of iron towards shoots. Besides, with this nitrogen source there was not accumulation of nitrate in the plant tissues. In nitric feeding case, the nitrate is mainly accumulated in the roots of the two cultivars. It is noticeable that the sensitive cultivar (‘PS’) accumulates three times more nitrate than the tolerant one (‘MK’). On the level of the whole plant, the iron and phosphorus nutrition seems unaltered by the nitrogen form.
Optical Constants of In1-xGaxSb Ternary Alloys: Experiment and Modeling

The optical spectra of Zn1-xCdxTe ternary alloys in the 1.1-5.6-eV photon-energy range at room temperature have been measured by spectroscopic ellipsometry (SE). The optical constants reported here are the complex dielectric constant (e=e1+ie2), complex refractive index (n*=n+ik), absorption coefficient (α) and normal-incidence reflectivity (R). The measured data are analyzed on the basis of a simplified model of the interband transitions. The experimental data reveal distinct structures in the optical spectra at energies of the E0, E0+Δ0, E1, E1+Δ1 and E2 transitions, and are in reasonable agreement with the theoretical model. The model proposed here enables us to obtain the optical response in Zn1-xCdxTe alloys of arbitrary composition (x) and photon energy (E=\hbarω).
Loss‐on‐Ignition in the Determination of Pools of Organic Carbon in Soils of Forests and Afforested Arable Fields

Abstract Loss‐on‐ignition (LOI) and concentration of organic carbon (Cc) were determined on pristine forest soils and soils from afforested arable fields. The objectives were to investigate the relation between the Cc of soil estimated indirectly from LOI and true Cc from dry combustion (CLECO) and further to evaluate how the applied analytical method affects the carbon pool estimates. According to results, LOI was a good indicator of Cc in the organic layer. As regards mineral soil, however, CLECO/LOI ratio significantly decreased with increasing depth, and the ratio changed differently in soils underlying forest sites as opposed to the soils from former fields. The results indicate that estimation of carbon pools from conversion factors would lead to considerable bias and that direct measurement of Cc is preferable to the use of any Cc/LOI ratio. The results also emphasize the need for elimination of carbonate carbon when measuring Cc from the soil of arable fields.
Crystal structure and cation transport properties of the layered monodiphosphates : Li9M3(P2O7)3(PO4)2 (M = Al, Ga, Cr, Fe)

A new series of isotypic monodiphosphates of general formula Li9M3(P2O7)3(PO4)2withM=Al, Ga, Cr, Fe was synthesized by flux methods. The crystal structure of the aluminum and iron members is described here. They crystallize in the trigonal space groupP3c1 witha=9.553(1),c=13.492(2) A (M=Al),a=9.726(1),c=13.615(2) A (M=Fe) andZ=2. The structure consists of2∞[(MP2O7)3(PO4)2]9−corrugated layers, parallel to (001), separated by lithium ions. The layers are built up ofMO6octahedra sharing corners with PO4tetrahedra and P2O7groups. Three nonequivalent lithium ions are present according to the structural formula Li(1)1Li(2)2Li(3)6[MP(2)2O7]3[P(1)O4]2. The crystals exhibit a lithium ion conduction mainly parallel to (001) but with rather low conductivity values:σ//(001)=1.3×10−4and 3.0×10−6Ω−1cm−1at 300°C forM=Fe andM=Al, respectively. In the presence of acidic aqueous solutions, Li9Fe3(P2O7)3(PO4)2undergoes an ion-exchange reaction between Li+and H+with the introduction of water molecules, which causes a one-dimensional expansion of the crystals perpendicular to the layers.
CELLULAR BIOLOGICAL EFFECTS AND A SINGLE TRANSTRACHEAL INJECTION TEST IN THREE TYPES OF WHISKER FIBERS

Recently, various kinds of asbestos substitutes have been used over a wide range of industrial applications. The dimensions of whisker fibers are similar to some forms ofasbestos, thus raising the concern of potential health effects for workers exposed in occupational environments. In this experiment, we compared the in vitro activity in cellular assays and the in vivo activity, focusing on lung inflammatory and fibrotic effects by a single transtracheal injection test among three well-characterized whisker fibers. The geometrical mean and SD of length (mum) and width (mum) and the numbers of fibers per microgram are: silicon carbide whisker (SC1), 6.4 +/- 2.45, 0.30 +/- 1.58, 0.3 x 106; titanium oxide whisker (TO1), 2.1 +/- 2.0, 0.14 +/- 1.5, 0.63 x 10 6; potassium titanate whisker (PT1), 6.0 +/- 2.0, 0.35 +/- 1.51, 0.51 x 10 6). The RAW 264.7 murine macrophage-like cell line was used for target cells. UICC crocidolite and TiO2 (rutile) particles were used as a positive and a negative control, respective.
Electronic Structure of Helicenes, C 2 S Helicenes, and Thiaheterohelicenes

The structures of linearly and ortho-fused helical polyaromatic hydrocarbon oligomers and polymers and their isoelectronic thiophene variants are studied using density functional theory (DFT). Structural and optical absorption data are compared with experiments where possible and excellent agreement is obtained. The results are interpreted with reference to orbital interaction diagrams. Infinite helicene tends to adopt a symmetry close to 61. C2S helicene is predicted to have an approximately 263 symmetry leading to an interdigitated S···S network parallel to the helical axis. Thiaheterohelicene has an approximately 72 helical structure. Periodic boundary condition (PBC) calculation and highest occupied molecular orbital (HOMO)−lowest unoccupied molecular orbital (LUMO) gap extrapolation at the B3LYP/6-31G* level indicate a smaller band gap for helicene compared to phenacene. This difference is mainly due to the gap reducing effects of the transannular π−π interactions across the helical pitch in helicene.
Trabajos de indagación de los alumnos: instrumentos de evaluación e identificación de dificultades

The aim of this research is to identify the capacities and difficulties shown by bachelors (aged 18) in the inquiry competence. In order to analyse the characteristics of inquiry competence, an assessment tool, NPTAI, has been designed on the basis of the Practical Test Assessment Inventory proposed by Tamir, Nussinovitz y Fridler. This tool has been used to analyse research works made by a group of high school science students and has enabled us to detect the aspects of scientific inquiry where students have the most difficulties. The recodification of results obtained with NPTAI has made it possible to establish an ordinal scale of bachelors’ inquiry levels or NCI.
Complex study on chitosan degradability

Results of photo- and thermodegradation of chitosan of different degrees of deacetylation (DD) were discussed. On the basis of the results of thermodegradation under isothermal and dynamic conditions thermal stability of chitosan films, also photochemically modified samples (UV irradiated for 1 h), was estimated. Investigations under isothermal conditions were carried out in the air atmosphere and cover the temperature range from 100°C to 200°C. Basing on the results of weight loss it was found that most susceptible to degradation was the sample of the higher DD; with an increase of temperature the observed changes were more distinct. Both during thermo- and photodegradation a decrease of DD of chitosan was observed. Modification of chitosan films by UV irradiation decreases the characteristic parameters of thermodestruction.