Influence of germination time on the morphological, morphometric, structural, and physicochemical characteristics of Esmeralda and Perla barley starch.

The aim of this study was to analyzing the impact of germination time on the morphology, crystallinity, gelatinization and viscosity properties on the starch of Esmeralda and Perla barley variety. The two barley were germinated for 1 to 8 days, at 26 °C and 65% relative humidity. Micrographs showed the presence of pinholes and eroded surfaces. Starch in Esmeralda was hydrolyzed completely at 8 days of germination. Birefringence was reduced from day 4, losing molecular structuring of the crystalline area. Morphometric data: fractal dimension, area, perimeter, circularity, and roundness decreased significantly along germination time in both varieties. The entropy increased significantly, from 0.79 to 10.09 in Esmeralda and from 0.46 to 7.57 in Perla. Relative crystallinity decreased significantly in the Perla from 24.7% to 23.6%. Viscosity peaks were also significantly reduced, pasting temperature was constant in Esmeralda but in Perla was significantly reduced from 95.43 to 95.19 °C with germination, the gelatinization temperature increased significantly in the Esmeralda while in Perla it remained constant. Enthalpy decreased significantly to 75.8% and 37% in Esmeralda and Perla respectively. The study of germination impact on structural and physicochemical properties is important to identify the use of hydrolyzed starches in the food industry or others.

Diabetes is associated with a higher risk of mortality among women in a middle-income country: Results form the Mexican Teacher's cohort study.

AIMS: In Mexico City, the mortality rate among patients with diabetes appears to be four times that of people without diabetes. Our study aimed to refine analyses of the impact of diabetes on mortality in a large cohort of women from different areas in Mexico with healthcare insurance. METHODS: Our study followed 111,299 women with comprehensive healthcare coverage from the Mexican Teachers' Cohort. After a median follow-up of 7.8years, 5514 (5%) prevalent self-reported diabetes cases and 4023 incident cases were identified, while deaths were identified through employers' databases and next-of-kin reports, with dates and causes of death for 1121 women obtained from mortality databases. Hazard ratios (HRs) for total and cause-specific mortality were estimated by Cox regression models, using follow-up time as the time scale and allowing for time-variable diabetes status after adjusting for age, socioeconomic status, use of health services, and anthropometric and lifestyle variables. RESULTS: In multivariable-adjusted models, the HR for all-cause mortality was 3.28 (95% CI: 2.86-3.75) in women with vs. without diabetes. The impact of diabetes on mortality was higher in rural vs. urban areas (HR: 4.72 vs. 2.98, respectively). HRs were 1.57 and 23.44 for cancer and renal disease mortality, respectively. CONCLUSION: In women with healthcare coverage in Mexico, the magnitude of the association between diabetes and all-cause mortality was higher than that observed in high-income countries, but less than what has previously been reported for Mexico. Such elevated mortality suggests a lack of adequate access to quality diabetes care in the population despite comprehensive healthcare coverage.

Measured and calculated SF-6 collision and swarm ion transport data in SF6 -Ar and SF6 -Xe mixtures.

The measurement of the mobility of SF-6 in the mixtures SF6 -Ar and SF6 -Xe is reported over the density-reduced electric field strength E/N 1-180 Td (1 Townsend = 10(-17) V cm(2)), from a time-resolved pulsed Townsend technique. Simultaneously, the mobility of SF-6 in the same binary mixtures has been calculated from a set of collision cross sections for SF-6 -Ar, SF-6 -Xe, and SF-6 - SF6 using a Monte Carlo simulation procedure for ion transport. The good agreement between measured and calculated mobilities in these gas mixtures has led us to conclude that the validation of our cross section sets is confirmed. The elastic collision cross section, a predominant process for ion energies lower than about 10 eV, was determined from a semiclassical JWKB approximation using a rigid core potential model for the ion-neutral systems under consideration. This elastic cross section was then added to several other inelastic collision cross sections found in the literature for ion conversion, electron detachment of SF-6 and charge transfer. Moreover, the calculations of the mobility and the ratios of the transverse and longitudinal diffusion coefficients to the mobility were extended into a much wider E/N range from 1 to 4000 Td. Additionally, we have also calculated the energy distribution functions and the reaction coefficients for ion conversion and electron detachment. Finally, we have shown that the range of validity for the calculation of the mobility in gas mixtures from Blanc's law is only valid for the low E/N region, where the interaction is dominated by elastic collisions and the ion distribution function remains essentially Maxwellian.

Electron drift velocities in mixtures of helium and xenon and experimental verification of corrections to Blanc's law.

Measurements of electron drift velocities were performed in pure Xe and He and in a number of mixtures ranging up to 70% of Xe. The data were obtained by using a pulsed Townsend technique over the density-normalized electric field strength E/N between 1 and 100 Td . Even for pure gases there are no data in the entire range covered here, and these data represent an extension of accurate drift velocities to higher E/N. A selection of well-established cross sections for low energies, which was extended to higher energies, led to a reasonably good agreement of the calculated transport coefficients with the available data. At the same time we have applied the standard (common E/N) Blanc's law and two forms of common mean energy (CME, due to Chiflykian) procedures. Blanc's law fails for most mixtures at low and moderate E/N, while the CME procedure is capable of following the experimental data for the mixtures much more closely, and even predicting the negative differential conductivity region when such effect does not exist for pure gases. Thus the present paper also represents an experimental test of procedures to correct the standard Blanc's law. Finally, we have used the data for two mixtures to obtain results for the third mixture and in all cases this procedure gave excellent results even though only the standard Blanc's law was used in the process.

Plasmodium vivax: ookinete destruction and oocyst development arrest are responsible for Anopheles albimanus resistance to circumsporozoite phenotype VK247 parasites.

Anopheles albimanus and An. pseudopunctipennis differ in their susceptibilities to Plasmodium vivax circumsporozoite phenotypes. An. pseudopunctipennis is susceptible to phenotype VK247 but almost refractory to VK210. In contrast, An. albimanus is almost refractory to VK247 but susceptible to VK210. To investigate the site in the mosquito and the parasite stage at which resistance mechanisms affect VK247 development in An. albimanus, parasite development was followed in a series of experiments in which both mosquitoes species were simultaneously infected with blood from patients. Parasite phenotype was determined in mature oocysts and salivary gland sporozoites by use of immunofluorescence and Western blot assays and/or gene identification. Ookinete maturation and their densities within the bloodmeal bolus were similar in both mosquito species. Ookinete densities on the internal midgut surface of An. albimanus were 4.7 times higher than those in An. pseudopunctipennis; however, the densities of developing oocysts on the external midgut surface were 6.12 times higher in the latter species. Electron microscopy observation of ookinetes in An. albimanus midgut epithelium indicated severe parasite damage. These results indicate that P. vivax VK247 parasites are destroyed at different parasite stages during migration in An. albimanus midguts. A portion, accumulated on the internal midgut surface, is probably destroyed by the mosquito's digestive enzymes and another portion is most likely destroyed by mosquito defense molecules within the midgut epithelium. A third group, reaching the external midgut surface, initiates oocyst development, but over 90% of them interrupt their development and die. The identification of mechanisms that participate in parasite destruction could provide new elements to construct transgenic mosquitoes resistant to malaria parasites.

Description and morphometric analysis of the eggs of Anopheles (Anopheles) vestitipennis (Diptera: Culcidae) from southern Mexico.

Light and scanning electron microscopy were used to compare the eggs of Anopheles vestitipennis Dyar & Knab females collected from human and animal baits in 9 villages of southern Mexico. An. vestitipennis eggs are boat-shaped, with lateral floats extending the length of the egg. Both the deck and dorsal surface are covered with hexagonal and pentagonal chorionic cells that contain round tubercles in the cell field. Crowns that enclose 3-5 lobed tubercles are present at both egg poles. By light microscopy, the mean length/width ratio of eggs of females caught at human bait were statistically different from those of females caught in horse-baited animal traps. In a regression tree model that included 19 egg attributes, the same egg groups could be separated by their posterior crown length/width ratio and mean anterior cell deck form factor (an index of their roundness). These findings support of the possible existence of 2 An. vestitipennis subpopulations with different host preferences in southern Mexico.

Validity and reproducibility of a food frequency questionnaire to assess dietary intake of women living in Mexico City.

OBJECTIVE: To assess the reproducibility and validity of a 116 item semi-quantitative food frequency questionnaire (FFQ), designed to assess the relation between dietary intake and chronic diseases. MATERIAL AND METHODS: To test the reproducibility of the FFQ questionnaire, the FFQ was administered twice to 134 women residing in Mexico City at an interval of approximately one year; to assess the validity we compared results obtained by the FFQs with those obtained by four 4-day 24-hour recalls at three month intervals. Validity and reproducibility were evaluated using regression analysis and Pearson and intraclass correlation coefficients of log-e and calorie-adjusted nutrient scores. RESULTS: Mean values for intake of most nutrients assessed by the two food frequency questionnaires were similar. However, means for the 24-hr recall were significantly lower. Intraclass correlation coefficients for nutrient intakes, assessed by questionnaires, administered one year apart, ranged from 0.38 for cholesterol to 0.54 for crude fiber. Correlation coefficients between energy-adjusted nutrient intakes, measured by diet recalls, and the first FFQ ranged from 0.12 for polyunsaturated fatty acids to 0.67 for saturated fatty acids. Regression coefficients between 24-hr recall and FFQ,s were all significant were significant for all nutrients, except for polyunsaturated fat, folic acid, vitamin E and Zinc. CONCLUSIONS: These data indicate that this semi-quantitative FFQ is reproducible and provides a useful estimate by which to categorize individuals by level of past nutrient intake. However, its application outside Mexico City or in different age and gender populations will require additional modifications and validation efforts.