Reduction of atmospheric emissions due to switching from fuel oil to natural gas at a power plant in a critical area in Central Mexico.

A case study was conducted to evaluate the SO2 emission reduction in a power plant in Central Mexico, as a result of the shifting of fuel oil to natural gas. Emissions of criteria pollutants, greenhouse gases, organic and inorganic toxics were estimated based on a 2010 report of hourly fuel oil consumption at the "Francisco Pérez Ríos" power plant in Tula, Mexico. For SO2, the dispersion of these emissions was assessed with the CALPUFF dispersion model. Emissions reductions of > 99% for SO2, PM and Pb, as well as reductions >50% for organic and inorganic toxics were observed when simulating the use of natural gas. Maximum annual (993 µg/m3) and monthly average SO2 concentrations were simulated during the cold-dry period (152-1063 µg/m3), and warm-dry period (239-432 µg/m3). Dispersion model results and those from Mexico City's air quality forecasting system showed that SO2 emissions from the power plant affect the north of Mexico City in the cold-dry period. The evaluation of model estimates with 24 hr SO2 measured concentrations at Tepeji del Rio suggests that the combination of observations and dispersion models are useful in assessing the reduction of SO2 emissions due to shifting in fuels. Being SO2 a major precursor of acid rain, high transported sulfate concentrations are of concern and low pH values have been reported in the south of Mexico City, indicating that secondary SO2 products emitted in the power plant can be transported to Mexico City under specific atmospheric conditions. Implications: Although the surroundings of a power plant located north of Mexico City receives most of the direct SO2 impact from fuel oil emissions, the plume is dispersed and advected to the Mexico City metropolitan area, where its secondary products may cause acid rain. The use of cleaner fuels may assure significant SO2 reductions in the plant emissions and consequent acid rain presence in nearby populated cities and should be compulsory in critical areas to comply with annual emission limits and health standards.

Global monitoring of volcanic SO2 degassing with unprecedented resolution from TROPOMI onboard Sentinel-5 Precursor.

Over the last four decades, space-based nadir observations of sulfur dioxide (SO2) proved to be a key data source for assessing the environmental impacts of volcanic emissions, for monitoring volcanic activity and early signs of eruptions, and ultimately mitigating related hazards on local populations and aviation. Despite its importance, a detailed picture of global SO2 daily degassing is difficult to produce, notably for lower-tropospheric plumes, due largely to the limited spatial resolution and coverage or lack of sensitivity and selectivity to SO2 of current (and previous) nadir sensors. We report here the first volcanic SO2 measurements from the hyperspectral TROPOspheric Monitoring Instrument (TROPOMI) launched in October 2017 onboard the ESA's Sentinel-5 Precursor platform. Using the operational processing algorithm, we explore the benefit of improved spatial resolution to the monitoring of global volcanic degassing. We find that TROPOMI surpasses any space nadir sensor in its ability to detect weak degassing signals and captures day-to-day changes in SO2 emissions. The detection limit of TROPOMI to SO2 emissions is a factor of 4 better than the heritage Aura/Ozone Monitoring Instrument (OMI). Here we show that TROPOMI SO2 daily observations carry a wealth of information on volcanic activity. Provided with adequate wind speed data, temporally resolved SO2 fluxes can be obtained at hourly time steps or shorter. We anticipate that TROPOMI SO2 data will help to monitor global volcanic daily degassing and better understand volcanic processes and impacts.

Antimalarial activity of neurolenin B and derivates of Eupatorium inulaefolium (Asteraceae).

Dried stems and leaves of Eupatorium inulaefolium (Austroeupatorium inulaefolium) (Asteraceae) were used to obtain four crude extracts (hexane, dichloromethane, methanol and ethanol). Two fractions were obtained from the hexane extract (S1 and S2) and three compounds (neurolenin B, lobatin A and lobatin B) from the dichloromethane extract. The ethanol, hexane, dichloromethane and methanol extracts, two fractions from the hexane extract (S1 and S2), and neurolenin B were evaluated in vitro against Plasmodium falciparum, FCB-2 strain. Two extracts (dichloromethane and methanol), the S2 fraction and neurolenin B showed statistically significant antiplasmodial activity.

Antitumor and antiviral activity of Colombian medicinal plant extracts.

Extracts of nine species of plants traditionally used in Colombia for the treatment of a variety of diseases were tested in vitro for their potential antitumor (cytotoxicity) and antiherpetic activity. MTT (Tetrazolium blue) and Neutral Red colorimetric assays were used to evaluate the reduction of viability of cell cultures in presence and absence of the extracts. MTT was also used to evaluate the effects of the extracts on the lytic activity of herpes simplex virus type 2 (HSV-2). The 50% cytotoxic concentration (CC50) and the 50% inhibitory concentration of the viral effect (EC50) for each extract were calculated by linear regression analysis. Extracts from Annona muricata, A. cherimolia and Rollinia membranacea, known for their cytotoxicity were used as positive controls. Likewise, acyclovir and heparin were used as positive controls of antiherpetic activity. Methanolic extract from Annona sp. on HEp-2 cells presented a CC50 value at 72 hr of 49.6x10(3)mg/ml. Neither of the other extracts examined showed a significant cytotoxicity. The aqueous extract from Beta vulgaris, the ethanol extract from Callisia grasilis and the methanol extract Annona sp. showed some antiherpetic activity with acceptable therapeutic indexes (the ratio of CC50 to EC50). These species are good candidates for further activity-monitored fractionation to identify active principles.

Antitumor and Antiviral Activity of Colombian Medicinal Plant Extracts

Extracts of nine species of plants traditionally used in Colombia for the treatment of a variety of diseases were tested in vitro for their potential antitumor (cytotoxicity) and antiherpetic activity. MTT (Tetrazolium blue) and Neutral Red colorimetric assays were used to evaluate the reduction of viability of cell cultures in presence and absence of the extracts. MTT was also used to evaluate the effects of the extracts on the lytic activity of herpes simplex virus type 2 (HSV-2). The 50 percent cytotoxic concentration (CC50) and the 50 percent inhibitory concentration of the viral effect (EC50) for each extract were calculated by linear regression analysis. Extracts from Annona muricata, A. cherimolia and Rollinia membranacea, known for their cytotoxicity were used as positive controls. Likewise, acyclovir and heparin were used as positive controls of antiherpetic activity. Methanolic extract from Annona sp. on HEp-2 cells presented a CC50 value at 72 hr of 49.6x103mg/ml. Neither of the other extracts examined showed a significant cytotoxicity. The aqueous extract from Beta vulgaris, the ethanol extract from Callisia grasilis and the methanol extract Annona sp. showed some antiherpetic activity with acceptable therapeutic indexes (the ratio of CC50 to EC50). These species are good candidates for further activity-monitored fractionation to identify active principles

10-Oximeguanacone, the first nitrogenated acetogenin derivative found to be a potent inhibitor of mitochondrial complex I.

A new 10-keto bis-tetrahydrofuran acetogenin, guanacone (1), has been isolated from a cytotoxic extract of Annona aff. spraguei seeds. The 10-oximeguanacone derivative 1f is the first bioactive nitrogenated acetogenin found to be a very potent inhibitor of complex I. In addition, a SAR study of guanacone analogues is reported based on the titration of the NADH oxidase and NADH:ubiquinone oxidoreductase activities.

[Aggressive behavior of the male volcano mouse Neotomodon alstoni (Rodentia: Cricetidae)]. / Comportamiento agresivo del macho del ratón de los volcanes Neotomodon alstoni (Rodentia: Cricetidae).

A study was carried out on the agonistic behavior of the male volcano mouse, Neotomodon alstoni, with 50 pairs of males which were classified as possible dominants (D) and subordinates (S), utilizing Melzack-Thompson's Method. The aggressiveness levels exhibited by this mouse were recording in the combinations: D vs. D and S vs. S. Two groups were formed: Group I with 12 pairs of D males and 13 of S males, and Group II with 11 pairs of D males and 14 of S males. In Group I the aggressiveness level was quantified after one week of mating and after another week of isolation, and in Group II the sequence of observation was inverted. The aggressiveness level was measured by the number of attacks per hour, an attack being defined as the aggressive physical contac of an animal (aggressor) with another (attacked). The kinds of behavior registered, including offense, defense, and submission patterns, revealed hierarchic relationships. Dominance was correlated significatively (p < 0.05) with a higher level of aggressiveness.

[Biliary calculi in the golden hamster. XXXVII. The prophylactic action of the creosote bush (Larrea tridentata) in pigmented cholelithiasis produced by vitamin A]. / Cálculos biliares en el jámster dorado. XXXVII. Acción preventiva de "gobernadora" (Larrea tridentata) en la colelitiasis pigmentaria producida por la vitamina A.

In the present work the results of an experiment performed in the golden hamster (Mesocricetus auratus), strain ChCM, are presented, in which the possible preventive action of pigment cholelithiasis by a powdered, desiccated, hydroalcoholic extract of leaves of "gobernadora" (Larrea tridentata) was studied. The extract was added to the lithogenic diet (basic diet + 25,000 I.U. of Vitamin A) at the 4% level; the hamsters were fed with the experimental diets during 70 days. The results showed that the group which received the diet with "gobernadora" did not develop pigment cholelithiasis, whereas the group that received the lithogenic diet alone developed cholelithiasis in 63% of cases. It is suggested that the active principle present in the leaves of "gobernadora", responsible for the prevention of the cholelithiasis is nordihydroguiaretic acid (NDGA), a potent antioxidant. On the other hand, the hamsters that received the diet containing "gobernadora" showed serious signs of toxicity and pathological changes, such as a marked reduction of growth, pronounced irritability and aggressiveness, and a marked hypoplasia both testicular and of the accessory sex glands.

Gallstones in the golden hamster. XXXVI. Pigment cholelithiasis produced by retinoic acid.

Previously we have reported on the pigmentary lithogenic action of vitamin A in the form of retinol acetate. In the present work the possible lithogenic action of retinoic acid was tested, since this differs from retinol in several metabolic aspects, which can contribute to the understanding of the pathogenesis of the pigment cholelithiasis produced by vitamin A. Two experiments were performed in which the lithogenicity of retinol acetate added to a colony chow at the level of 25,000 IU%, was compared with that of 3 dietetic levels of all-trans retinoic acid. In the first experiment seric triglycerides were determined in order to establish whether there is a relation between the hypertriglyceridemic effect of retinoids and their lithogenicity; in the second experiment GPT and GOT were determined as indicators of hepatotoxicity. The results showed that the retinoic acid at levels of 24,000 and 35,000 IU% of diet, produced a cholelithiasis incidence similar to that of 25,000 IU% of retinol acetate, whereas the retinoic acid level of 12,000 IU% was not lithogenic. The dietetic retinoic acid produced a reduction of hepatic vitamin A, that was directly proportional to the level supplied. There was no relation between the hypertriglyceridemic effect of retinoids and its lithogenicity. The retinoids produced a light increase in GPT, which was higher with retinol acetate, whereas GOT had not significative changes. It is concluded that all-trans retinoic acid produces pigment gallstones in the hamster, with an incidence similar to that produced by retinol acetate.

[The biology of the volcano mouse (N. a. alstoni). XXI. Reproductive capacity of wild females in 15 successive matings]. / Estudios sobre la biología del ratón de los volcanes (N. a. alstoni). XXI. Capacidad reproductora de hembras silvestres en 15 apareamientos sucesivos.

This study comprises an investigation on the reproductive capacity of wild females of the volcano mouse (Neotomodon alstoni alstoni), in 15 successive matings. The neotomodon were captured in the Sierra del Volcán Ajusco (Cerro Pelado, Parres, D.F.). The animals were kept under environmental laboratory conditions, being fed ALBI-LAB pellets and tap water. The matings were performed from may 1985 to August 1988 by pairs and at random, during 12 days. The females were weighed on the day 1 of the mating; the young were sexed on the 7th day of life, and weaned at the 30th day of age. The results were: the mean of the percentages of pregnancy in the 15 matings was 39.6 +/- 3.0, being the highest percentages in Spring-Summer. The size of the litter varied from 1 to 6 young, with a mode of 3 and a global average of 2.7. The means of the percentages of survival at the first week of life and at weaning were 72.9 +/- 3.6 and 70.3 +/- 3.3, respectively. The proportion males-females was 1.2:1. There was not found a significant positive correlation between the weight of the mothers at day 1 of the mating and the size of the litter (r = 0.65, p less than 0.05). These results allow to conclude that in the laboratory the wild volcano mouse exhibits a high reproductive capacity, which demonstrates that this rodent posseses very positive qualities in order to make out of him a new experimental animal.

[Biliary calculi in th golden hamster (M. a. auratus). XXXV. Effect of the hydrogenation of Polifat KA-02 on its preventive activity against pigment cholelithiasis]. / Cálculos biliares en el jámster dorado (M. a. auratus). XXXV. Efecto de la hidrogenización del Polifat KA-02 sobre su acción preventiva de la colelitiasis pigmentaria.

It has been previously reported that Polifat KA-02 (fatty acids derived from safflower oil) prevents the pigment cholelithiasis produced by vitamin A in the golden hamster. In order to establish whether the saturation or the unsaturation of Polifat is directly related with its preventive action, in the present study the effect of the hydrogenation of the derivative on this preventive action was tested. Two experiments were carried out in which the animals received the different experimental diets ad libitum during 70 days. In the 1st. experiment the effect of the additions to the lithogenic diet (Rodents Chow + 25,000 UI% of retinol acetate) of 18% of crude safflower oil, or 15% Polifat, or 15% hydrogenated Polifat (approx. 80% saturation) were assayed. In the 2nd. experiment the effect of a more hydrogenated Polifat KA-02 (greater than 99%) was tested. The results of the 1st. experiment showed that the lithogenic diet produced a high incidence (90.5%) of animals with gallstones, which was very similar (100%) to that produced by the crude safflower oil, whereas the additions of normal and hydrogenated Polifat completely prevented the formation of gallstones. The 2 forms of Polifat produced a considerable hepatomegaly. The absorption of vitamin A, measured as total hepatic vitamin A, was higher in the 3 groups that received extra lipids in their diets. The results of the 2nd. experiment fully confirmed the findings related to the hydrogenated Polifat. It is concluded that hydrogenated Polifat KA-02 prevents, as normal Polifat does it, the pigment cholelithiasis in the golden hamster produced by vitamin A.

[Biology of the volcano mouse (N. a. alstoni). XVII. Blood chemistry of animals born in the laboratory (F1)]. / Estudios sobre la biología del ratón de los volcanes (N.a. alstoni). XVII. Química sanguínea de animales nacidos en el laboratorio (F1).

This work reports an initial study of the blood chemistry of young adult (between 129 to 155 days of age), laboratory born (F1) volcano mouse (Neotomodon alstoni alstoni). The blood biochemical values determined were glucose, cholesterol, total bilirubin, total protein, albumin and globulin, as well as the electrolytes sodium, potassium, chloride, calcium and phosphorus. In most of the values there were no differences statistically significant between males and females; only the values of total bilirubin and potassium were slightly higher in females, with differences statistically significant. The values of glucose and cholesterol showed a wide range of variation in the animals of both sexes. Although several studies dealing with the blood chemistry of various laboratory rodents have been published, the experimental conditions in which these investigations were carried out were so different to the ones of the present work that cannot be compared; neither a comparison can be made of the present results with those of the blood chemistry of the members of the Peromyscus genus, which is the most phylogenetically close to the Neotomodon genus, since, as far as we know, there has been no studies reported on this subject on Peromyscus.

[Biology of the volcano mouse (N. a. alstone). XVI. Comparison of the reproductive capacity of wild females in the laboratory, following 3 mating systems]. / Estudios sobre la biología del ratón de los volcanes (N. a. alstoni). XVI. Comparación de la capacidad reproductora de hembras silvestres en el laboratorio, siguiendo 3 sistemas de apareamiento.

The aim of the present work was the comparison of the reproductive capacity of the wild volcano mouse (Neotomodon alstoni alstoni) in the laboratory, using 3 mating systems: pair, harem and collective. The mice were captured in the Sierra del Volcán Ajusco (Cerro Pelado, Parres, D. F.) The animals were kept in plastic cages with sawdust bedding under room conditions of light, humidity and temperature. They were fed with ALBI-LAB Pellets and tap water, supplemented with carrots and lettuce. All mice were under quarantine for 30 days before the matings begun. These were done in 2 series: pair versus harem (1 male with 4 females), and pair versus collective (2 males with 4 females). Each system had initially 25 females; 4 consecutive pairings were done with each mating system used in both series, with a duration of 12 days each mating. Statistical analysis of the results was done using the square chi test. The data registered in the 4 matings of each pairing system used in the 2 series were: number of mated females, number and percentage of pregnant females, total of offspring born, mean litter number, number and percentage of live offspring at the and of the first week after birth and at weaning, and relation and proportion males-females. The comparative tables of the reproductive records of all the 4 matings of each pairing system used in the 2 series, were analyzed separately and as a whole; the global comparative table (totals of the 2 series) of the reproductive record of neotomodon, according to the 3 systems of mating, i. e., pair (P), harem (H) and collective (C) showed the following results: P = number of mated females, 189; number of pregnant females, 94; percentage of pregnant females, 49.7; total of offspring born, 286; mean litter number, 3.04; number of offsprings alive at the end of the first week after birth, 173; percentage of offsprings alive at the end of the first week after birth, 60.5; number of offsprings alive at weaning, 172; percentage of offsprings alive at weaning, 60.1.(ABSTRACT TRUNCATED AT 400 WORDS)

Morphological changes in the sex glands of aged and orchidectomized hamsters.

Authors deals with a comparative study of the microscopical changes, principally of the sex glands, found in old intact and in old orchidectomized hamsters. They could see that in the Sertoli cells of the testis, and in the epithelial cells of the seminal vesicle and coagulating gland of the aged intact hamsters, a few lipofuscin granules were present. After orchidectomy the amount of lipofuscin granules increased, showing that their age related changes can be increased by orchidectomy.