A case-control study was conducted in a brickmaker’s community in Juarez City, Chihuahua in Mexico. This population has been chronically exposed to a wide spectrum of potentially health-damaging pollutants that inclu...A case-control study was conducted in a brickmaker’s community in Juarez City, Chihuahua in Mexico. This population has been chronically exposed to a wide spectrum of potentially health-damaging pollutants that include coarse, fine and ultrafine particles, carbon monoxide (CO), oxides of nitrogen and sulphur, transitional metals, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds and bioaerosols. Lipid peroxidation level (LPX) and protein carbonyl content (PCC) help to evaluate oxidized protein content and activity of the antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were evaluated in blood samples of study participants. The group of occupationally exposed (OE) workers consisted of 30 individuals ranging in age from 25 to 55 years, with a mean of 15 years in a brick production-related job. The control group included 30 volunteers who were neither environmentally nor occupationally exposed to brick production activities and whose sociodemo-graphic characteristics were similar to the OE group. Results indicate that none of workers used any type of protective equipment (respirator or face mask, gloves, coveralls) during brick manufacturing. LPX and PCC significantly increased (p < 0.5) in the OE group compared to the control group. SOD, CAT and GPx activity was significantly increased (p < 0.5) in the OE group compared to the control group. Therefore, evaluation of stress oxidative biomarkers is advisable in order to assay chronic exposure to workers in brick manufacturing.展开更多
The Desierto de los Leones National Park is a place that features recreational activities for residents and visitors to Mexico City. The Presa de los Patos (Ducks Dam) is one of the many bodies of water that are prese...The Desierto de los Leones National Park is a place that features recreational activities for residents and visitors to Mexico City. The Presa de los Patos (Ducks Dam) is one of the many bodies of water that are present in the park. By means of physico-chemical and microbiological analysis, it was determined that the water of the Presa de los Patos cannot be considered potable. The pH range was between 5.5 - 5.9. The turbidity exceeded the values established in the standards (10.7 - 32.3 Nephelometric Turbidity Units (NTU’s)). Chemical Oxygen Demand (COD) showed that large amounts of oxygen are needed to oxidize organic matter (106 - 450 mg/L). The amount of coliforms and fecal coliforms exceeds the values established by the standards used (total coliforms 98 - 956 Colony Forming Units (CFU’s), fecal coliforms 78 - 807 CFU’s). Five bacterial genera (Escherichia coli, Pseudomona, Klebsiella, Shigella and Salmonella) were isolated and identified. Most of the bacteria isolated were resistant to ampicillin (90%), while 25% were resistant to ciprofloxacin. The water consumption of the Presa de los Patos is a great risk for the habitants and visitors of the park.展开更多
This report describes a new record and two unusual and rare species of marine algae collected from Oaxaca, Michoacán, Jalisco and Baja California Sur at Mexican Pacific coast. Boodleopsis verticillata is the firs...This report describes a new record and two unusual and rare species of marine algae collected from Oaxaca, Michoacán, Jalisco and Baja California Sur at Mexican Pacific coast. Boodleopsis verticillata is the first record in the Pacific shore of Mexico, in the case of Melobesia polystromatica, this is the sixth record at tropical Pacific while Litholepis sonorensisis reported for the third time in the Gulf of California. These results suggest that the taxonomic inventory of seaweed in the Pacific coast of Mexico is not yet complete, so attention must be given to the epiphytes, and other small and delicate species that inhabit the coast of Mexico. Morphological descriptions, distributional range, reproductive stage and samples examined are included.展开更多
A constant increase in dive tourism over the past years in the Revillagigedo National Park, Mexico, could result in a stressful scenario for giant mantas (Mobula birostris). The purpose of this study was to determine ...A constant increase in dive tourism over the past years in the Revillagigedo National Park, Mexico, could result in a stressful scenario for giant mantas (Mobula birostris). The purpose of this study was to determine the degree of oxidative stress in terms of changes in catalase units (CAT) and muscle glycogen concentration in this species during two periods of different tourism intensity in this protected area. A total of 21 muscle biopsies were collected in March (peak tourism) and November (lower tourism), 2019. Stress biomarkers were analysed by commercial kits from the company Cayman Chemical. Oxidative stress (catalase activity) was significantly higher during the period with lower tourism (p = 0.002), compared to the period with more tourism, suggesting the presence of the general adaptation syndrome. In males, there was a significant difference (p = 0.0005) in oxidative stress between periods of different tourism intensity, suggesting that the reproductive season may be a stressor. Morphotypes showed different oxidative stress (p = 0.031);however, the reason is unknown. No statistical differences were detected in glycogen concentrations between the tourism periods (p = 0.123), probably because this polysaccharide is not a proper indicator of chronic stress in giant mantas. Based on these findings, giant mantas may have an adequate response in terms of oxidative stress due to an increase in tourism;however the observed increase in catalase suggests that it is within the tolerance range of these organisms.展开更多
The intensification of anthropic uses (i.e., increase of the hemerobic condition) threatens the remnants of native vegetation due to the reduction of its self-regulation capacity. In this research, the Distance to Nat...The intensification of anthropic uses (i.e., increase of the hemerobic condition) threatens the remnants of native vegetation due to the reduction of its self-regulation capacity. In this research, the Distance to Nature (D2N) index for land use and land cover was applied in the Río Grande de Comitán watershed (Southern Mexico) to answer the following questions: 1) What were the land use dynamics observed in the Rio Grande de Comitán watershed in the trajectory through 1999, 2009 and 2019? 2) Does the subcategorization of the D2N allow one to identify which anthropic uses influence more the territorial expression of the watershed? To answer these questions, we performed a supervised classification of land use and land cover was performed in this watershed, and for the D2N index, the classification was simplified to three-category scale for the subcategorization of the anthropic component. Through Principal Component Analysis (PCA), we identified that agricultural anthropogenic use had the greatest influence on territorial expression. The reported scenario indicates a trend of gradual and continuous reduction of naturalness over the last 20 years. Additionally, the D2N index proved to be a useful tool to demonstrate both the anthropic impact, with the simplified scale, and the component that most influences the territory, by subcategorizing the anthropic scale.展开更多
This paper aims to contribute to the prevention of natural disasters and generate a complement to other similar studies. The Popocatépetl volcano has showed significant and constant activity since 1994. The Color...This paper aims to contribute to the prevention of natural disasters and generate a complement to other similar studies. The Popocatépetl volcano has showed significant and constant activity since 1994. The Colorada and Quimichule canyons are located within its geologic structure;due to their topographic features, ejected volcanic material and torrential rains in the past recent years, they put nearby communities at risk. This work presents a geostatistical analysis to obtain the gravity acceleration, slope by the distance-elevation relation, height-gravity and the fluid force on the canyons. The conversion of UTM to geographical coordinates was made with the use of the program Traninv applying the ITRF2008 epoch 2010.0 Datum and the 14 Zone;the local gravity was calculated with the use of International Organization of Legal Metrology (OIML) and the statistical analysis was obtained with the use of the Geostatistical Environmental Assessment. The structural modeling was performed using Surfer, and the spending and force were calculated using hydrological models. The correlation analysis concluded that Quimichule has the greatest gravity and that it would transport lahars faster. Mapping, geomorphological and statistical techniques and models were applied in accordance with the study to obtain the results presented here.展开更多
In this study, radon-222 concentrations were measured within 34 houses distributed in the northern, southern, and central areas of the city of Querétaro in 2007. The objective of this study was to establish the s...In this study, radon-222 concentrations were measured within 34 houses distributed in the northern, southern, and central areas of the city of Querétaro in 2007. The objective of this study was to establish the spatial distribution of radon with respect to geological faults and its relation to certain environmental variables. For each sampling site, the radon-222 concentration was analyzed as a function of various climate variables, relative humidity, temperature, and atmospheric pressure, in addition to the ventilation of the house and distance of each site from any geological faults in the area. A multivariate statistical technique was used to analyze these variables based on two components. For component 1, the relative humidity and temperature had the greatest weight, 0.677 and 0.492, respectively, while for component 2, the greatest weights corresponded to radon and the temperature with 0.693 and 0.609, respectively. The average radon concentration across the entire sampling period was 38.92 Bq/m3, the minimum detected value was 6.01 Bq/m3?for site 91GAG0607, and the maximum detected value was 225.95 Bq/m3?for site 91CAM20907. This last value is outside the standards permitted by the Environmental Protection Agency of the United Stated, which is 148 Bq/m3?for indoor environments. With respect to geological faults and their relationship to radon-222, the concentrations for the sampling sites had no relationship to the closeness or distance to these faults.展开更多
Chronic kidney disease(CKD) typically evolves over many years, with a long latent period when the disease is clinically silent and therefore diagnosis, evaluation and treatment is based mainly on biomarkers that asses...Chronic kidney disease(CKD) typically evolves over many years, with a long latent period when the disease is clinically silent and therefore diagnosis, evaluation and treatment is based mainly on biomarkers that assess kidney function. Glomerular filtration rate(GFR) remains the ideal marker of kidney function. Unfortunately measuring GFR is time consuming and therefore GFR is usually estimated from equations that take into account endogenous filtration markers like serum creatinine(SCr) and cystatin C(Cys C). Other biomarkers such as albuminuria may precede kidney function decline and have demonstrated to have strong associationswith disease progression and outcomes. New potential biomarkers have arisen with the promise of detecting kidney damage prior to the currently used markers. The aim of this review is to discuss the utility of the GFR estimating equations and biomarkers in CKD and the different clinical settings where these should be applied. The CKD-Epidemiology Collaboration equation performs better than the modification of diet in renal disease equation, especially at GFR above 60 m L/min per 1.73 m2. Equations combining Cys C and SCr perform better than the equations using either Cys C or SCr alone and are recommended in situations where CKD needs to be confirmed. Combining creatinine, Cys C and urine albumin to creatinine ratio improves risk stratification for kidney disease progression and mortality. Kidney injury molecule and neutrophil gelatinase-associated lipocalin are considered reasonable biomarkers in urine and plasma to determine severity and prognosis of CKD.展开更多
An increased interest in the antioxidant effects of medicinal plants has developed in recent years.Identifying antioxidant compounds present in medicinal plants and elucidating the mechanism by which they prevent oxid...An increased interest in the antioxidant effects of medicinal plants has developed in recent years.Identifying antioxidant compounds present in medicinal plants and elucidating the mechanism by which they prevent oxidation have been the focus of the research community.We performed a systematic and exhaustive review aimed at analyzing the available data regarding the beneficial effects of secondary metabolites in plants.The result of this review is presented as a description of free radicals,as well as cellular and physiological oxidative stress,is provided.The origin and source of antioxidant compounds,and the cellular and molecular mechanism by which they exert antioxidant effects,have been reported.The absorption,distribution and,elimination of antioxidants are mentioned.The beneficial effects of secondary metabolites of medicinal plants in various high incidence disease conditions were also reviewed.Finally,disease states that benefit from antioxidant compounds includes diabetes,cancer,cardiovascular diseases,and liver,brain and,intestinal diseases.展开更多
AIM Evaluate the association between phase angle and the development of hepatic encephalopathy in the longterm follow-up of cirrhotic patients.METHODS This was a prospective cohort study. Clinical, nutritional and bio...AIM Evaluate the association between phase angle and the development of hepatic encephalopathy in the longterm follow-up of cirrhotic patients.METHODS This was a prospective cohort study. Clinical, nutritional and biochemical evaluations were performed. MannWhitney's U and χ2 tests were used as appropriate. Kaplan-Meier curves and Cox proportional Hazards analysis were used to evaluate the prediction and incidence of hepatic encephalopathy.RESULTS Two hundred and twenty were included; the most frequent etiology of cirrhosis was hepatitis C infection, 52% of the patients developed hepatic encephalopathy(18.6% covert and 33.3% overt); the main precipitating factors were infections and variceal bleeding. KaplanMeier curves showed a higher proportion of HE in the group with low phase angle(39%) compared to the normal phase angle group(13%)(P = 0.012). Furthermore, creatinine and phase angle remained independently associated to hepatic encephalopathy in the Cox regression multivariate analysis [hazard ratio = 1.80(1.07-3.03)]. CONCLUSION In our cohort of patients low phase angle was associated with an increased incidence of hepatic encephalopathy. Phase angle is a useful nutritional marker that evaluates cachexia and could be used as a part of the integral assessment in patients with cirrhosis.展开更多
AIM: To evaluate the technical failures of the Bravo pH test in a population with nonerosive gastroesophageal reflux disease. METHODS: Over the course of a year, we prospectively studied a population of 66 nonerosive ...AIM: To evaluate the technical failures of the Bravo pH test in a population with nonerosive gastroesophageal reflux disease. METHODS: Over the course of a year, we prospectively studied a population of 66 nonerosive reflux disease patients who received a Bravo pH test. The number and frequency of all technical failures were documented, quantified and analyzed. RESULTS: A total of 66 patients, with a mean age of 41.7 years, were studied. Technical failures occurred in 15.15% of the sample. The most frequent failures were due to poor data reception (4.5%), early dislodgement (4.5%) and capsule removal (6.1%). CONCLUSION: The Bravo capsule pH test involves a low but non-negligible rate of technical problems, a fact that must always be considered by physicians.展开更多
Intracerebroventricular administration (ICV) of streptozotocin (STZ) in rats has been associated to desensitization of the insulin receptor (IR) and biochemical changes similar to those occurring in Alzheimer’s disea...Intracerebroventricular administration (ICV) of streptozotocin (STZ) in rats has been associated to desensitization of the insulin receptor (IR) and biochemical changes similar to those occurring in Alzheimer’s disease (AD) or older brains, so it has been proposed as a suitable model for studying some of the pathological features of AD sporadic type (SAD). In this study, we investigated the role of glycogen synthase kinase 3β (GSK3β) and protein phosphatase 2A (PP2A) in the regulation of the phosphorylation of tau (p-tau). Results showed that ICV-STZ treated rats had deficits in short- (1.5-h) and long-term (24- and 48-h) memory after one month of ICV-STZ treatment and six months relative to control rats. The memory deficit was associated to increasing [F(3, 12) = 31.48, p β (p-GSK3β) and PP2A in hippocampus and PFC, indicating that GSK3β and PP2A contributed to regulation of p-tau. These data supporting the model with ICV-STZ in rat are adequate to study the progressive memory impairment associated to hyperphosphorylation of tau and the cascade of insulin receptor signaling;confirm that phosphatidyl-inositol-3 kinase-protein kinase B (PI3K-PKB/Akt-GSK3β) and PP2A are involved in the modulation of proteins responsible for the regulation of neurodegeneration in AD.展开更多
The potential of polyphenols for treating chronic-degenerative diseases(particularly neurodegenerative diseases)is attractive.However,the selection of the best polyphenol for each treatment,the mechanisms by which the...The potential of polyphenols for treating chronic-degenerative diseases(particularly neurodegenerative diseases)is attractive.However,the selection of the best polyphenol for each treatment,the mechanisms by which they act,and their efficacy are frequently discussed.In this review,the basics and the advances in the field,as well as suggestions for using natural and synthetic polyphenols alone or in a combinatorial strategy with stem cell assays,are compiled and discussed.Thus,stem cells exhibit several responses when polyphenols are added to their environment,which could provide us with knowledge for advancing the elucidation of the origin of neurodegeneration.But also,polyphenols are being included in the innovative strategies of novel therapies for treating neurodegenerative diseases as well as metabolic diseases related to neurodegeneration.In this regard,flavonoid compounds are suggested as the best natural polyphenols due to their several mechanisms for acting in ameliorative effects;but increasing reports are involving other polyphenols.Even if some facts limiting bioactivity prevent them from conventional use,some natural polyphenols and derivatives hold the promise for being improved compounds,judged by their induced effects.The current results suggest polyphenols as enhancers of stem cell therapy against the targeted diseases.展开更多
Over the past century,age-related diseases,such as cancer,type-2 diabetes,obesity,and mental illness,have shown a significant increase,negatively impacting overall quality of life.Studies on aged animal models have un...Over the past century,age-related diseases,such as cancer,type-2 diabetes,obesity,and mental illness,have shown a significant increase,negatively impacting overall quality of life.Studies on aged animal models have unveiled a progressive discoordination at multiple regulatory levels,including transcriptional,translational,and post-translational processes,resulting from cellular stress and circadian derangements.The circadian clock emerges as a key regulator,sustaining physiological homeostasis and promoting healthy aging through timely molecular coordination of pivotal cellular processes,such as stem-cell function,cellular stress responses,and inter-tissue communication,which become disrupted during aging.Given the crucial role of hypothalamic circuits in regulating organismal physiology,metabolic control,sleep homeostasis,and circadian rhythms,and their dependence on these processes,strategies aimed at enhancing hypothalamic and circadian function,including pharmacological and non-pharmacological approaches,offer systemic benefits for healthy aging.Intranasal brain-directed drug administration represents a promising avenue for effectively targeting specific brain regions,like the hypothalamus,while reducing side effects associated with systemic drug delivery,thereby presenting new therapeutic possibilities for diverse age-related conditions.展开更多
This paper aims to evaluate the feasibility of pressure-dependent models in the design of ship piping systems.For this purpose,a complex ship piping system is designed to operate in firefighting and bilge services thr...This paper aims to evaluate the feasibility of pressure-dependent models in the design of ship piping systems.For this purpose,a complex ship piping system is designed to operate in firefighting and bilge services through jet pumps.The system is solved as pressure-dependent model by the piping system analysis software EPANET and by a mathematical approach involving a piping network model.This results in a functional system that guarantees the recommendable ranges of hydraulic state variables(flow and pressure)and compliance with the rules of ship classification societies.Through this research,the suitability and viability of pressure-dependent models in the simulation of a ship piping system are proven.展开更多
This research is framed within the affective computing, which explains the importance of emotions in human cognition (decision making, perception, interaction and human intelligence). Applying this approach to a pedag...This research is framed within the affective computing, which explains the importance of emotions in human cognition (decision making, perception, interaction and human intelligence). Applying this approach to a pedagogical agent is an essential part to enhance the effectiveness of the teaching-learning process of an intelligent learning system. This work focuses on the design of the inference engine that will give life to the interface, where the latter is represented by a pedagogical agent. The inference engine is based on an affective-motivational model. This model is implemented by using artificial intelligence technique called fuzzy cognitive maps.展开更多
Microbial infections are typically initiated by the colonization of tissues by a specific mechanism that promotes adherence to host cells or tissues. In this work, we characterized the ability of Gallibacterium anatis...Microbial infections are typically initiated by the colonization of tissues by a specific mechanism that promotes adherence to host cells or tissues. In this work, we characterized the ability of Gallibacterium anatis F149T to express fimbriae that may be involved in mucosal attachment. Using transmission electron microscopy, the fimbriae-like structures could be observed on the surface of negatively stained G. anatis F149T, and these structures were further visualized after being released by physical shaking. When the fimbriae-like structures were separated by SDS-PAGE, the proteins comprising them were isolated and sized at 13 and 25 kDa. G. anatis F149T was able to adhere to chicken oropharyngeal epithelial cells. Adhesion could be completely inhibited by pretreatment of the bacterial cells with trypsin, whereas 25% inhibition was attained after pretreatment with an antiserum against the 13 kDa protein. We demonstrated by immuno-gold electron microscopy that the antibodies from the antiserum were specifically associated with the fimbria-like structures on G. anatis. These results indicated that G. anatis F149T expresses fimbriae that contribute to its adhesion to chicken oropharyngeal epithelial cells and may be important for colonization of the upper respiratory tract.展开更多
Large quantities of spent hydrodesulfurization (HDS) catalysts are available from petrochemical industry. Disposal of spent catalyst is a problem as it falls under the category of hazardous industrial waste due to its...Large quantities of spent hydrodesulfurization (HDS) catalysts are available from petrochemical industry. Disposal of spent catalyst is a problem as it falls under the category of hazardous industrial waste due to its vanadium concentration. Most of these catalysts are usually supported on alumina containing a variable percentage of elements such as nickel or molybdenum. Hence these catalysts contain environmentally critical, and economically valuable metals such as molyb denum, vanadium, and, nickel. In this paper, a spent HDS catalyst was treated with caustic soda solution. Parameters such as temperature, time, and NaOH solution concentration have been studied thoroughly, in order to settle the appropriate conditions for the maximum recovery of molybdenum and vanadium. Under the best leaching conditions (20 %w NaOH, room temperature, 2 h) about 95% recovery of Mo and V was achieved, and the recovery of nickel obtained was of 99% in the form of NiAlO4.展开更多
Residue conversion by combining catalytic hydrotreating and delayed coking has been evaluated comparatively with both processes alone.Optimal operating conditions are defined to achieve the greatest economic benefit f...Residue conversion by combining catalytic hydrotreating and delayed coking has been evaluated comparatively with both processes alone.Optimal operating conditions are defined to achieve the greatest economic benefit for upgrading an atmospheric residue from a heavy crude oil.A literature model was adapted to simulate the hydrotreating reactor,and for delayed coking,correlations reported in the literature were used.The results with both approaches were employed to calculate the techno-economic feasibility of the combined process scheme.The combination of hydrotreating and delayed coking presented an increase in light fractions of 29% and a reduction in coke production of 47.8%.Based on the calculated net benefit values,it was demonstrated that the combination of hydrotreating and delayed coking is technically and economically better than using each process alone,with highest benefit of 57.7 USD·m^(-3).展开更多
<b>Background:</b> Peripheral block techniques for total hip arthroplasty have been used as an analgesic strategy, only a few studies described it as an anesthetic technique, so the perioperative performan...<b>Background:</b> Peripheral block techniques for total hip arthroplasty have been used as an analgesic strategy, only a few studies described it as an anesthetic technique, so the perioperative performance and safety are poorly studied. <b>Methods:</b> 78 total hip arthroplasties were prospectively observed in our hospital. Divided into 2 groups: 1) General anesthesia;and 2) Lumbar sacral plexus block anesthesia. Variables measured in both groups were: demographics, conversion to general anesthesia, total opioid doses, surgical time, blood loss, postoperative pain, use and total dose of vasopressors drugs, transfusion and ICU transfer needs, postoperative ambulation time, and length of hospital stay. T student and chi-square tests were used upon the case. A significant difference was considered when a value of p < 0.05 was obtained. Descriptive statistics were performed in frequency, percentages, variance and standard deviation. <b>Results:</b> 3 patients (7.3%) anesthetized with combined lumbar sacral plexus block were converted to general anesthesia. When comparing peripheral nerve block and general anesthesia, less intraoperative (p = 0.000) and postoperative (p = 0.002) opioid consumption were noted, less postoperative pain in PACU (p = 0.002) and in the first 24 hours (p = 0.005), as well as earlier onset of ambulation (p = 0.008) and shorter hospital stay (p = 0.031). <b>Conclusions:</b> In our study, the lumbar and sacral plexus block anesthesia technique provided anesthetic conditions to perform hip joint arthroplasty and it was proved to be advantageous in comparison to general anesthesia.展开更多
文摘A case-control study was conducted in a brickmaker’s community in Juarez City, Chihuahua in Mexico. This population has been chronically exposed to a wide spectrum of potentially health-damaging pollutants that include coarse, fine and ultrafine particles, carbon monoxide (CO), oxides of nitrogen and sulphur, transitional metals, polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds and bioaerosols. Lipid peroxidation level (LPX) and protein carbonyl content (PCC) help to evaluate oxidized protein content and activity of the antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were evaluated in blood samples of study participants. The group of occupationally exposed (OE) workers consisted of 30 individuals ranging in age from 25 to 55 years, with a mean of 15 years in a brick production-related job. The control group included 30 volunteers who were neither environmentally nor occupationally exposed to brick production activities and whose sociodemo-graphic characteristics were similar to the OE group. Results indicate that none of workers used any type of protective equipment (respirator or face mask, gloves, coveralls) during brick manufacturing. LPX and PCC significantly increased (p < 0.5) in the OE group compared to the control group. SOD, CAT and GPx activity was significantly increased (p < 0.5) in the OE group compared to the control group. Therefore, evaluation of stress oxidative biomarkers is advisable in order to assay chronic exposure to workers in brick manufacturing.
文摘The Desierto de los Leones National Park is a place that features recreational activities for residents and visitors to Mexico City. The Presa de los Patos (Ducks Dam) is one of the many bodies of water that are present in the park. By means of physico-chemical and microbiological analysis, it was determined that the water of the Presa de los Patos cannot be considered potable. The pH range was between 5.5 - 5.9. The turbidity exceeded the values established in the standards (10.7 - 32.3 Nephelometric Turbidity Units (NTU’s)). Chemical Oxygen Demand (COD) showed that large amounts of oxygen are needed to oxidize organic matter (106 - 450 mg/L). The amount of coliforms and fecal coliforms exceeds the values established by the standards used (total coliforms 98 - 956 Colony Forming Units (CFU’s), fecal coliforms 78 - 807 CFU’s). Five bacterial genera (Escherichia coli, Pseudomona, Klebsiella, Shigella and Salmonella) were isolated and identified. Most of the bacteria isolated were resistant to ampicillin (90%), while 25% were resistant to ciprofloxacin. The water consumption of the Presa de los Patos is a great risk for the habitants and visitors of the park.
文摘This report describes a new record and two unusual and rare species of marine algae collected from Oaxaca, Michoacán, Jalisco and Baja California Sur at Mexican Pacific coast. Boodleopsis verticillata is the first record in the Pacific shore of Mexico, in the case of Melobesia polystromatica, this is the sixth record at tropical Pacific while Litholepis sonorensisis reported for the third time in the Gulf of California. These results suggest that the taxonomic inventory of seaweed in the Pacific coast of Mexico is not yet complete, so attention must be given to the epiphytes, and other small and delicate species that inhabit the coast of Mexico. Morphological descriptions, distributional range, reproductive stage and samples examined are included.
文摘A constant increase in dive tourism over the past years in the Revillagigedo National Park, Mexico, could result in a stressful scenario for giant mantas (Mobula birostris). The purpose of this study was to determine the degree of oxidative stress in terms of changes in catalase units (CAT) and muscle glycogen concentration in this species during two periods of different tourism intensity in this protected area. A total of 21 muscle biopsies were collected in March (peak tourism) and November (lower tourism), 2019. Stress biomarkers were analysed by commercial kits from the company Cayman Chemical. Oxidative stress (catalase activity) was significantly higher during the period with lower tourism (p = 0.002), compared to the period with more tourism, suggesting the presence of the general adaptation syndrome. In males, there was a significant difference (p = 0.0005) in oxidative stress between periods of different tourism intensity, suggesting that the reproductive season may be a stressor. Morphotypes showed different oxidative stress (p = 0.031);however, the reason is unknown. No statistical differences were detected in glycogen concentrations between the tourism periods (p = 0.123), probably because this polysaccharide is not a proper indicator of chronic stress in giant mantas. Based on these findings, giant mantas may have an adequate response in terms of oxidative stress due to an increase in tourism;however the observed increase in catalase suggests that it is within the tolerance range of these organisms.
文摘The intensification of anthropic uses (i.e., increase of the hemerobic condition) threatens the remnants of native vegetation due to the reduction of its self-regulation capacity. In this research, the Distance to Nature (D2N) index for land use and land cover was applied in the Río Grande de Comitán watershed (Southern Mexico) to answer the following questions: 1) What were the land use dynamics observed in the Rio Grande de Comitán watershed in the trajectory through 1999, 2009 and 2019? 2) Does the subcategorization of the D2N allow one to identify which anthropic uses influence more the territorial expression of the watershed? To answer these questions, we performed a supervised classification of land use and land cover was performed in this watershed, and for the D2N index, the classification was simplified to three-category scale for the subcategorization of the anthropic component. Through Principal Component Analysis (PCA), we identified that agricultural anthropogenic use had the greatest influence on territorial expression. The reported scenario indicates a trend of gradual and continuous reduction of naturalness over the last 20 years. Additionally, the D2N index proved to be a useful tool to demonstrate both the anthropic impact, with the simplified scale, and the component that most influences the territory, by subcategorizing the anthropic scale.
文摘This paper aims to contribute to the prevention of natural disasters and generate a complement to other similar studies. The Popocatépetl volcano has showed significant and constant activity since 1994. The Colorada and Quimichule canyons are located within its geologic structure;due to their topographic features, ejected volcanic material and torrential rains in the past recent years, they put nearby communities at risk. This work presents a geostatistical analysis to obtain the gravity acceleration, slope by the distance-elevation relation, height-gravity and the fluid force on the canyons. The conversion of UTM to geographical coordinates was made with the use of the program Traninv applying the ITRF2008 epoch 2010.0 Datum and the 14 Zone;the local gravity was calculated with the use of International Organization of Legal Metrology (OIML) and the statistical analysis was obtained with the use of the Geostatistical Environmental Assessment. The structural modeling was performed using Surfer, and the spending and force were calculated using hydrological models. The correlation analysis concluded that Quimichule has the greatest gravity and that it would transport lahars faster. Mapping, geomorphological and statistical techniques and models were applied in accordance with the study to obtain the results presented here.
基金partially supported by Dirección General de Asuntos Académicos,Universidad Nacional Autónoma de México,Projects PAPIIT IN114806 and PAPIIT IN120808.
文摘In this study, radon-222 concentrations were measured within 34 houses distributed in the northern, southern, and central areas of the city of Querétaro in 2007. The objective of this study was to establish the spatial distribution of radon with respect to geological faults and its relation to certain environmental variables. For each sampling site, the radon-222 concentration was analyzed as a function of various climate variables, relative humidity, temperature, and atmospheric pressure, in addition to the ventilation of the house and distance of each site from any geological faults in the area. A multivariate statistical technique was used to analyze these variables based on two components. For component 1, the relative humidity and temperature had the greatest weight, 0.677 and 0.492, respectively, while for component 2, the greatest weights corresponded to radon and the temperature with 0.693 and 0.609, respectively. The average radon concentration across the entire sampling period was 38.92 Bq/m3, the minimum detected value was 6.01 Bq/m3?for site 91GAG0607, and the maximum detected value was 225.95 Bq/m3?for site 91CAM20907. This last value is outside the standards permitted by the Environmental Protection Agency of the United Stated, which is 148 Bq/m3?for indoor environments. With respect to geological faults and their relationship to radon-222, the concentrations for the sampling sites had no relationship to the closeness or distance to these faults.
文摘Chronic kidney disease(CKD) typically evolves over many years, with a long latent period when the disease is clinically silent and therefore diagnosis, evaluation and treatment is based mainly on biomarkers that assess kidney function. Glomerular filtration rate(GFR) remains the ideal marker of kidney function. Unfortunately measuring GFR is time consuming and therefore GFR is usually estimated from equations that take into account endogenous filtration markers like serum creatinine(SCr) and cystatin C(Cys C). Other biomarkers such as albuminuria may precede kidney function decline and have demonstrated to have strong associationswith disease progression and outcomes. New potential biomarkers have arisen with the promise of detecting kidney damage prior to the currently used markers. The aim of this review is to discuss the utility of the GFR estimating equations and biomarkers in CKD and the different clinical settings where these should be applied. The CKD-Epidemiology Collaboration equation performs better than the modification of diet in renal disease equation, especially at GFR above 60 m L/min per 1.73 m2. Equations combining Cys C and SCr perform better than the equations using either Cys C or SCr alone and are recommended in situations where CKD needs to be confirmed. Combining creatinine, Cys C and urine albumin to creatinine ratio improves risk stratification for kidney disease progression and mortality. Kidney injury molecule and neutrophil gelatinase-associated lipocalin are considered reasonable biomarkers in urine and plasma to determine severity and prognosis of CKD.
文摘An increased interest in the antioxidant effects of medicinal plants has developed in recent years.Identifying antioxidant compounds present in medicinal plants and elucidating the mechanism by which they prevent oxidation have been the focus of the research community.We performed a systematic and exhaustive review aimed at analyzing the available data regarding the beneficial effects of secondary metabolites in plants.The result of this review is presented as a description of free radicals,as well as cellular and physiological oxidative stress,is provided.The origin and source of antioxidant compounds,and the cellular and molecular mechanism by which they exert antioxidant effects,have been reported.The absorption,distribution and,elimination of antioxidants are mentioned.The beneficial effects of secondary metabolites of medicinal plants in various high incidence disease conditions were also reviewed.Finally,disease states that benefit from antioxidant compounds includes diabetes,cancer,cardiovascular diseases,and liver,brain and,intestinal diseases.
基金supported by CONACYT/UNAMsupported by Fundación para la Salud y Educación "Salvador Zubirán". Francisco Javier Cubero is a Ramón y Cajal Researcher (RYC-2014-15242)
文摘AIM Evaluate the association between phase angle and the development of hepatic encephalopathy in the longterm follow-up of cirrhotic patients.METHODS This was a prospective cohort study. Clinical, nutritional and biochemical evaluations were performed. MannWhitney's U and χ2 tests were used as appropriate. Kaplan-Meier curves and Cox proportional Hazards analysis were used to evaluate the prediction and incidence of hepatic encephalopathy.RESULTS Two hundred and twenty were included; the most frequent etiology of cirrhosis was hepatitis C infection, 52% of the patients developed hepatic encephalopathy(18.6% covert and 33.3% overt); the main precipitating factors were infections and variceal bleeding. KaplanMeier curves showed a higher proportion of HE in the group with low phase angle(39%) compared to the normal phase angle group(13%)(P = 0.012). Furthermore, creatinine and phase angle remained independently associated to hepatic encephalopathy in the Cox regression multivariate analysis [hazard ratio = 1.80(1.07-3.03)]. CONCLUSION In our cohort of patients low phase angle was associated with an increased incidence of hepatic encephalopathy. Phase angle is a useful nutritional marker that evaluates cachexia and could be used as a part of the integral assessment in patients with cirrhosis.
文摘AIM: To evaluate the technical failures of the Bravo pH test in a population with nonerosive gastroesophageal reflux disease. METHODS: Over the course of a year, we prospectively studied a population of 66 nonerosive reflux disease patients who received a Bravo pH test. The number and frequency of all technical failures were documented, quantified and analyzed. RESULTS: A total of 66 patients, with a mean age of 41.7 years, were studied. Technical failures occurred in 15.15% of the sample. The most frequent failures were due to poor data reception (4.5%), early dislodgement (4.5%) and capsule removal (6.1%). CONCLUSION: The Bravo capsule pH test involves a low but non-negligible rate of technical problems, a fact that must always be considered by physicians.
文摘Intracerebroventricular administration (ICV) of streptozotocin (STZ) in rats has been associated to desensitization of the insulin receptor (IR) and biochemical changes similar to those occurring in Alzheimer’s disease (AD) or older brains, so it has been proposed as a suitable model for studying some of the pathological features of AD sporadic type (SAD). In this study, we investigated the role of glycogen synthase kinase 3β (GSK3β) and protein phosphatase 2A (PP2A) in the regulation of the phosphorylation of tau (p-tau). Results showed that ICV-STZ treated rats had deficits in short- (1.5-h) and long-term (24- and 48-h) memory after one month of ICV-STZ treatment and six months relative to control rats. The memory deficit was associated to increasing [F(3, 12) = 31.48, p β (p-GSK3β) and PP2A in hippocampus and PFC, indicating that GSK3β and PP2A contributed to regulation of p-tau. These data supporting the model with ICV-STZ in rat are adequate to study the progressive memory impairment associated to hyperphosphorylation of tau and the cascade of insulin receptor signaling;confirm that phosphatidyl-inositol-3 kinase-protein kinase B (PI3K-PKB/Akt-GSK3β) and PP2A are involved in the modulation of proteins responsible for the regulation of neurodegeneration in AD.
基金supported by Secretaria de Investigación y Posgrado del Instituto Politécnico Nacional(IPN),No.M-2143.
文摘The potential of polyphenols for treating chronic-degenerative diseases(particularly neurodegenerative diseases)is attractive.However,the selection of the best polyphenol for each treatment,the mechanisms by which they act,and their efficacy are frequently discussed.In this review,the basics and the advances in the field,as well as suggestions for using natural and synthetic polyphenols alone or in a combinatorial strategy with stem cell assays,are compiled and discussed.Thus,stem cells exhibit several responses when polyphenols are added to their environment,which could provide us with knowledge for advancing the elucidation of the origin of neurodegeneration.But also,polyphenols are being included in the innovative strategies of novel therapies for treating neurodegenerative diseases as well as metabolic diseases related to neurodegeneration.In this regard,flavonoid compounds are suggested as the best natural polyphenols due to their several mechanisms for acting in ameliorative effects;but increasing reports are involving other polyphenols.Even if some facts limiting bioactivity prevent them from conventional use,some natural polyphenols and derivatives hold the promise for being improved compounds,judged by their induced effects.The current results suggest polyphenols as enhancers of stem cell therapy against the targeted diseases.
基金supported by National Council of Science and Technology(CONACYT)(grants FC 2016/2672 and FOSISS 272757),INMEGEN(09/2017/I)the Ministry of Education,Science,Technology and Innovation of Mexico City(SECTEI)(grant 228/2021).
文摘Over the past century,age-related diseases,such as cancer,type-2 diabetes,obesity,and mental illness,have shown a significant increase,negatively impacting overall quality of life.Studies on aged animal models have unveiled a progressive discoordination at multiple regulatory levels,including transcriptional,translational,and post-translational processes,resulting from cellular stress and circadian derangements.The circadian clock emerges as a key regulator,sustaining physiological homeostasis and promoting healthy aging through timely molecular coordination of pivotal cellular processes,such as stem-cell function,cellular stress responses,and inter-tissue communication,which become disrupted during aging.Given the crucial role of hypothalamic circuits in regulating organismal physiology,metabolic control,sleep homeostasis,and circadian rhythms,and their dependence on these processes,strategies aimed at enhancing hypothalamic and circadian function,including pharmacological and non-pharmacological approaches,offer systemic benefits for healthy aging.Intranasal brain-directed drug administration represents a promising avenue for effectively targeting specific brain regions,like the hypothalamus,while reducing side effects associated with systemic drug delivery,thereby presenting new therapeutic possibilities for diverse age-related conditions.
文摘This paper aims to evaluate the feasibility of pressure-dependent models in the design of ship piping systems.For this purpose,a complex ship piping system is designed to operate in firefighting and bilge services through jet pumps.The system is solved as pressure-dependent model by the piping system analysis software EPANET and by a mathematical approach involving a piping network model.This results in a functional system that guarantees the recommendable ranges of hydraulic state variables(flow and pressure)and compliance with the rules of ship classification societies.Through this research,the suitability and viability of pressure-dependent models in the simulation of a ship piping system are proven.
文摘This research is framed within the affective computing, which explains the importance of emotions in human cognition (decision making, perception, interaction and human intelligence). Applying this approach to a pedagogical agent is an essential part to enhance the effectiveness of the teaching-learning process of an intelligent learning system. This work focuses on the design of the inference engine that will give life to the interface, where the latter is represented by a pedagogical agent. The inference engine is based on an affective-motivational model. This model is implemented by using artificial intelligence technique called fuzzy cognitive maps.
文摘Microbial infections are typically initiated by the colonization of tissues by a specific mechanism that promotes adherence to host cells or tissues. In this work, we characterized the ability of Gallibacterium anatis F149T to express fimbriae that may be involved in mucosal attachment. Using transmission electron microscopy, the fimbriae-like structures could be observed on the surface of negatively stained G. anatis F149T, and these structures were further visualized after being released by physical shaking. When the fimbriae-like structures were separated by SDS-PAGE, the proteins comprising them were isolated and sized at 13 and 25 kDa. G. anatis F149T was able to adhere to chicken oropharyngeal epithelial cells. Adhesion could be completely inhibited by pretreatment of the bacterial cells with trypsin, whereas 25% inhibition was attained after pretreatment with an antiserum against the 13 kDa protein. We demonstrated by immuno-gold electron microscopy that the antibodies from the antiserum were specifically associated with the fimbria-like structures on G. anatis. These results indicated that G. anatis F149T expresses fimbriae that contribute to its adhesion to chicken oropharyngeal epithelial cells and may be important for colonization of the upper respiratory tract.
文摘Large quantities of spent hydrodesulfurization (HDS) catalysts are available from petrochemical industry. Disposal of spent catalyst is a problem as it falls under the category of hazardous industrial waste due to its vanadium concentration. Most of these catalysts are usually supported on alumina containing a variable percentage of elements such as nickel or molybdenum. Hence these catalysts contain environmentally critical, and economically valuable metals such as molyb denum, vanadium, and, nickel. In this paper, a spent HDS catalyst was treated with caustic soda solution. Parameters such as temperature, time, and NaOH solution concentration have been studied thoroughly, in order to settle the appropriate conditions for the maximum recovery of molybdenum and vanadium. Under the best leaching conditions (20 %w NaOH, room temperature, 2 h) about 95% recovery of Mo and V was achieved, and the recovery of nickel obtained was of 99% in the form of NiAlO4.
基金the Mexican Institute of Petroleum(IMP)for the financial support。
文摘Residue conversion by combining catalytic hydrotreating and delayed coking has been evaluated comparatively with both processes alone.Optimal operating conditions are defined to achieve the greatest economic benefit for upgrading an atmospheric residue from a heavy crude oil.A literature model was adapted to simulate the hydrotreating reactor,and for delayed coking,correlations reported in the literature were used.The results with both approaches were employed to calculate the techno-economic feasibility of the combined process scheme.The combination of hydrotreating and delayed coking presented an increase in light fractions of 29% and a reduction in coke production of 47.8%.Based on the calculated net benefit values,it was demonstrated that the combination of hydrotreating and delayed coking is technically and economically better than using each process alone,with highest benefit of 57.7 USD·m^(-3).
文摘<b>Background:</b> Peripheral block techniques for total hip arthroplasty have been used as an analgesic strategy, only a few studies described it as an anesthetic technique, so the perioperative performance and safety are poorly studied. <b>Methods:</b> 78 total hip arthroplasties were prospectively observed in our hospital. Divided into 2 groups: 1) General anesthesia;and 2) Lumbar sacral plexus block anesthesia. Variables measured in both groups were: demographics, conversion to general anesthesia, total opioid doses, surgical time, blood loss, postoperative pain, use and total dose of vasopressors drugs, transfusion and ICU transfer needs, postoperative ambulation time, and length of hospital stay. T student and chi-square tests were used upon the case. A significant difference was considered when a value of p < 0.05 was obtained. Descriptive statistics were performed in frequency, percentages, variance and standard deviation. <b>Results:</b> 3 patients (7.3%) anesthetized with combined lumbar sacral plexus block were converted to general anesthesia. When comparing peripheral nerve block and general anesthesia, less intraoperative (p = 0.000) and postoperative (p = 0.002) opioid consumption were noted, less postoperative pain in PACU (p = 0.002) and in the first 24 hours (p = 0.005), as well as earlier onset of ambulation (p = 0.008) and shorter hospital stay (p = 0.031). <b>Conclusions:</b> In our study, the lumbar and sacral plexus block anesthesia technique provided anesthetic conditions to perform hip joint arthroplasty and it was proved to be advantageous in comparison to general anesthesia.
