The use of carbon from waste biomass has the potential to eliminate the drawbacks of Li-S batteries and improve their overall performance.Chrome-tanned-leather-shavings(CTLS)are a readily available waste product that ...The use of carbon from waste biomass has the potential to eliminate the drawbacks of Li-S batteries and improve their overall performance.Chrome-tanned-leather-shavings(CTLS)are a readily available waste product that can be transformed into porous carbon.We prepared an ac-tivated carbon by microwave pyrolysis combined with KOH activator using the CTLS as starting materials.The carbon had a specific surface area of 556 m^(2)g^(-1) and a honeycomb-like structure.Two kinds of N-doped activated carbons were then synthesized by thermal decomposition of the activated carbon,either combined with urea,or impregnated with eth-anolamine.Both N-doped activated carbons have an in-creased number of nitrogen and amine surface groups.However,only the urea treatment was effective in improv-ing the initial capacity of the cell(1363 mAh g^(-1)),which is probably linked to the sorption of long-chain polysulfides.This investigation confirms that it is possible to use the thermal de-composition of urea to obtain carbon materials from CTLS for use as the sulfur-host cathode in Li-S batteries and improve their performance.A radial basis function neural network was fitted to provide statistical support for the experimental results,which confirmed the importance of the nitrogen content of the carbons in determining the discharge capacity of the cells.展开更多
Paper devices have recently attracted considerable attention as a class of cost-effective cell culture substrates for various biomedical applications.The paper biomaterial can be used to partially mimic the in vivo ce...Paper devices have recently attracted considerable attention as a class of cost-effective cell culture substrates for various biomedical applications.The paper biomaterial can be used to partially mimic the in vivo cell microenvironments mainly due to its natural three-dimensional characteristic.The paper-based devices provide precise control over their structures as well as cell distributions,allowing recapitulation of certain interactions between the cells and the extracellular matrix.These features have shown great potential for the development of normal and diseased human tissue models.In this review,we discuss the fabrication of paper-based devices for in vitro tissue modeling,as well as the applications of these devices toward drug screening and personalized medicine.It is believed that paper as a biomaterial will play an essential role in the field of tissue model engineering due to its unique performances,such as good biocompatibility,eco-friendliness,cost-effectiveness,and amenability to various biodesign and manufacturing needs.展开更多
Segmenting vegetation in color images is a complex task, especially when the background and lighting conditions of the environment are uncontrolled. This paper proposes a vegetation segmentation algorithm that combine...Segmenting vegetation in color images is a complex task, especially when the background and lighting conditions of the environment are uncontrolled. This paper proposes a vegetation segmentation algorithm that combines a supervised and an unsupervised learning method to segment healthy and diseased plant images from the background. During the training stage, a Self-Organizing Map (SOM) neural network is applied to create different color groups from a set of images containing vegetation, acquired from a tomato greenhouse. The color groups are labeled as vegetation and non-vegetation and then used to create two color histogram models corresponding to vegetation and non-vegetation. In the online mode, input images are segmented by a Bayesian classifier using the two histogram models. This algorithm has provided a qualitatively better segmentation rate of images containing plants’ foliage in uncontrolled environments than the segmentation rate obtained by a color index technique, resulting in the elimination of the background and the preservation of important color information. This segmentation method will be applied in disease diagnosis of tomato plants in greenhouses as future work.展开更多
The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulf...The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulfate（CuSO4）.The best conditions obtained from screening experiments in shaken flasks using tomato juice,CuSO4,and soybean oil were integrated in an experimental design.Enhanced levels of tomato juice as the medium,CuSO4and soybean oil as inducers（36.8%（v/v）,3 mmol/L,and 1%（v/v）,respectively） were determined for 10 L stirred tank bioreactor runs.This combination resulted in laccase titer of 143000 IU/L（2,2＇-azino-bis（3-ethylbenzthiazoline-6- sulfonic acid）,pH 3.0）,which represents the highest activity so far reported for P.sanguineus in a 10-L fermentor.Other interesting media resulting from the screening included glucose-bactopeptone which increased laccase activity up to 20000 IU/L,whereas the inducers Acid Blue 62 and Reactive Blue 19 enhanced enzyme production in this medium 10 times.Based on a partial characterization,the laccases of this strain are especially promising in terms of thermostability（half-life of 6.1 h at 60 °C） and activity titers.展开更多
A simple and rapid Fourier Transform infrared (FTIR) spectroscopy method was developed to determine the main essential oil components (carvacrol, thymol and p-cymene) in the antimicrobial LDPE films incorporated with ...A simple and rapid Fourier Transform infrared (FTIR) spectroscopy method was developed to determine the main essential oil components (carvacrol, thymol and p-cymene) in the antimicrobial LDPE films incorporated with oregano (Origanum vulgare) and thyme (Thymus vulgaris) essential oils. The ATR-FTIR spectrum of pure active components (carvacrol, thymol and p-cymene) was characterized, and the ranges between 1125 cm-1 - 1095 cm-1, 1170 cm-1 - 1140 cm-1 and 1050 cm-1 - 1017 cm-1 were respectively used for quantitative estimation. Partial least square (PLS) analysis was used for quantitative analysis. FTIR spectroscopy with chemometrics, using the PLS-1st derivative spectra, could predict the content of active compounds accurate to an r2 greater than 0.99 and a standard error of prediction (SEP) less than 0.7. The developed method was successfully applied to predict the concentration of active compounds: carvacrol, thymol and p-cymene in oregano and thyme essential oils with results compared to those of the GC-MS method. The described non-destructive method can be applied in the industry instead of extraction, distillation and blend processes of the mentioned essential oils and can be extended to detect the content of carvacrol, thymol and p-cymene in active packaging and other commercial products.展开更多
BACKGROUND Fibroadenoma(FA)is the most common tumor found in young women,although it can occur in any age group.Ductal carcinoma in situ(DCIS)that is confined in a FA is rare;it is most frequently reported as an incid...BACKGROUND Fibroadenoma(FA)is the most common tumor found in young women,although it can occur in any age group.Ductal carcinoma in situ(DCIS)that is confined in a FA is rare;it is most frequently reported as an incidental finding.CASE SUMMARY We report a case of DCIS within a FA in a 46-year-old female without cancerrelated personal and family histories.The patient was diagnosed with a breast conglomerate of nodules and was followed for 1 year.In the current control image study,we found suspicious microcalcification,as a new finding,within one of the nodules.Consequently,a core biopsy of the tumor,which appeared hypoechoic,oval,and circumscribed,was performed.The pathological diagnosis was ductal carcinoma in situ within a fibroepithelial lesion.The patient underwent breastconserving surgery and received radiotherapy as well as endocrine therapy(tamoxifen).CONCLUSION We recommend a multidisciplinary approach for adequate treatment and followup.展开更多
Fatty liver has been present in the lives of patients and physicians for almost two centuries.Vast knowledge has been generated regarding its etiology and consequences,although a long path seeking novel and innovative...Fatty liver has been present in the lives of patients and physicians for almost two centuries.Vast knowledge has been generated regarding its etiology and consequences,although a long path seeking novel and innovative diagnostic biomarkers for nonalcoholic fatty liver disease(NAFLD)and nonalcoholic steatohepatitis(NASH)is still envisioned.On the one hand,proteomics and lipidomics have emerged as potential noninvasive resources for NAFLD diagnosis.In contrast,metabolomics has been able to distinguish between NAFLD and NASH,even detecting degrees of fibrosis.On the other hand,genetic and epigenetic markers have been useful in monitoring disease progression,eventually functioning as target therapies.Other markers involved in immune dysregulation,oxidative stress,and inflammation are involved in the instauration and evolution of the disease.Finally,the fascinating gut microbiome is significantly involved in NAFLD and NASH.This review presents state-of-the-art biomarkers related to NAFLD and NASH and new promises that could eventually be positioned as diagnostic resources for this disease.As is evident,despite great advances in studying these biomarkers,there is still a long path before they translate into clinical benefits.展开更多
The highly competitive offer of medical training programs and schools,globalization and constant mobility of physicians and medical students(MS),and the commitment to society to deliver competent physicians,demands th...The highly competitive offer of medical training programs and schools,globalization and constant mobility of physicians and medical students(MS),and the commitment to society to deliver competent physicians,demands the definition of performance standards.This would allow to make their performances comparable no matter where they studied or which textbook did they used as reference,to have evaluation mechanisms that guarantee mastery of the integral evaluation of the performance.Assessment has been the key in the teaching-learning process as this obtains a formative and summative element,at different moments,from the extent to which the students have acquired knowledge,skills and attitudes.The progress of the learner must be enhanced with effective feedback on their performance and self-direction of the results obtained in each of the mechanisms established.If,traditionally,this has been considered as the accreditation of compliance with a standard,the evaluation also functions in an integral way as a formative process that identifies advances and deficiencies in the training of residents that allows the definition of actions and strategies for improving the operation of the programs.Different assessment mechanisms are associated with the areas of competence domain,some of the most common tools are:theoretical exams,checklists and rubrics,portfolio,projects and challenges.However,the importance of defining standards which are perceived as fair and designed according to the learning objectives remains a priority to guarantee the credibility of the evaluation agencies and institutions.Some strategies to assure credibility include the involvement of expert and trained evaluators,allowing the process to be carried out with transparency and diligence,and the principles employed should be supported by educational research.展开更多
A rapid, cost effective and reliable analytical method was developed and validated for the simultaneous determination of four estrogens (17 β-estradiol, 17 α-ethinylestradiol, estrone, and estriol) in compost sample...A rapid, cost effective and reliable analytical method was developed and validated for the simultaneous determination of four estrogens (17 β-estradiol, 17 α-ethinylestradiol, estrone, and estriol) in compost samples from the biodegradation of biological infectious hazardous wastes. Ultrasonic solvent extraction, using methanol as extraction solvent, coupled with SPE clean-up, using cartridges HLB 60 mg - 6 ml Supelco®<sup></sup> and acetonitrile for reconstitution of eluents, was used for the simultaneous extraction of the four estrogens. Mean recoveries in the range of 98% - 107% were obtained. All compounds were separated in a single gradient run by UHPLC Kinetex<sup>TM</sup> 2.6 μm XB-C18 100 ÅLC (50 × 4.6 mm) column. Analytes were detected via multiple reaction monitoring (MRM) using an AB SCIEX API-5000TM triple quadrupole (Applied Biosystems/MDS SCIEX) with electrospray ionization in negative mode. Isocratic mobile phase of Water:ACN (50:50) resulted to be the optimum. Limits of detection and quantification were on the order of 0.66 ng·g<sup>-1</sup> and 2 ng·g<sup>-1</sup> for all the estrogens. These limits were lower than most of the values reported in the literature for similar matrices. Suitable level of linearity, good repeatability and reproducibility with coefficients of variation is lower than 11.7%, 6.8% and 8.3%, respectively.展开更多
This paper addresses the design of an exponential function-based learning law for artificial neural networks(ANNs)with continuous dynamics.The ANN structure is used to obtain a non-parametric model of systems with unc...This paper addresses the design of an exponential function-based learning law for artificial neural networks(ANNs)with continuous dynamics.The ANN structure is used to obtain a non-parametric model of systems with uncertainties,which are described by a set of nonlinear ordinary differential equations.Two novel adaptive algorithms with predefined exponential convergence rate adjust the weights of the ANN.The first algorithm includes an adaptive gain depending on the identification error which accelerated the convergence of the weights and promotes a faster convergence between the states of the uncertain system and the trajectories of the neural identifier.The second approach uses a time-dependent sigmoidal gain that forces the convergence of the identification error to an invariant set characterized by an ellipsoid.The generalized volume of this ellipsoid depends on the upper bounds of uncertainties,perturbations and modeling errors.The application of the invariant ellipsoid method yields to obtain an algorithm to reduce the volume of the convergence region for the identification error.Both adaptive algorithms are derived from the application of a non-standard exponential dependent function and an associated controlled Lyapunov function.Numerical examples demonstrate the improvements enforced by the algorithms introduced in this study by comparing the convergence settings concerning classical schemes with non-exponential continuous learning methods.The proposed identifiers overcome the results of the classical identifier achieving a faster convergence to an invariant set of smaller dimensions.展开更多
The potential of Plant Growth Promoting Rhizobacteria(PGPR)has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield.A.brasilense produces a wide variety of mo...The potential of Plant Growth Promoting Rhizobacteria(PGPR)has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield.A.brasilense produces a wide variety of molecules,including the natural auxin indole-3-acetic acid(IAA),as well as other phytoregulators.However,several studies have suggested that auxin induces changes in plant development during their interaction with the bacteria.The effects of A.brasilense Sp245 on the development of Arabidopsis thaliana root were investigated to help explain the molecular basis of the interaction.The results obtained showed a decrease in primary root length from the first day and remained so throughout the exposure,accompanied by a stimulation of initiation and maturation of lateral root primordia and an increase of lateral roots.An enhanced auxin response was evident in the vascular tissue and lateral root meristems of inoculated plants.However,after five days of bacterization,the response disappeared in the primary root meristems.The role of polar auxin transport(PAT)in auxins relocation involved the PGP1,AXR4-1,and BEN2 proteins,which apparently mediated A.brasilense-induced root branching of Arabidopsis seedlings.展开更多
Torin 1 is an ATP-competitive TOR inhibitor which inhibits the signaling of TOR and S6K kinase in mammals and plants.The objective of this research is to determine the effect of Torin 1 in a relatively simple and homo...Torin 1 is an ATP-competitive TOR inhibitor which inhibits the signaling of TOR and S6K kinase in mammals and plants.The objective of this research is to determine the effect of Torin 1 in a relatively simple and homogeneous plant system such as the NT-1 tobacco suspension cell cultures.Cultures of NT-1 cells were tested with 5,50,150 and 250 nM of Torin 1.During kinetics growth of NT-1 tobacco suspension cell cultures,150 and 250 nM Torin 1 inhibits the early growth and later enhanced the cellular proliferation during exponential growth by means of an increased expression of E2F1 and cyclin B.Furthermore,Torin 1 stimulates the growth of NT-1 cells during log phase with small shaped cell,characteristic of tobacco suspension cell cultures with high mitotic activity.展开更多
In this paper we study a continuous time random walk in the line with two boundaries [a,b], a < b. The particle can move in any of two directions with different velocities v1 and v2. We consider a special type of b...In this paper we study a continuous time random walk in the line with two boundaries [a,b], a < b. The particle can move in any of two directions with different velocities v1 and v2. We consider a special type of boundary which can trap the particle for a random time. We found closed-form expressions for the stationary distribution of the position of the particle not only for the alternating Markov process but also for a broad class of semi-Markov processes.展开更多
Hand injuries are a frequent problem in actual society.These are often caused while working or exercising,but simple everyday activities can also be the cause.The most common injuries are those related to soft tissue;...Hand injuries are a frequent problem in actual society.These are often caused while working or exercising,but simple everyday activities can also be the cause.The most common injuries are those related to soft tissue;specifically,muscles,tendons,and ligaments.To improve therapy results and reduce its cost and needed time,a self-rehabilitation system for soft tissue injuries in the hands was developed.The proposed system is meant to be implemented on Smart TVs and can be used in the home of the injured people.To identify the most common movements of the injured limbs,and design proper therapies to be displayed by the system,an exoskeleton prototype which supports four degrees of freedom of the hand was constructed.We examined scenarios to provide services for individuals and created a scenario-based prototype,which was tested by an exercise therapist to verify compliance with the requirements of users.展开更多
The aim of this study is to identify and analyze the pattern of visibility of the main actors in the photographic coverage of drug trafficking in six of Mexico’s national newspapers. The study was based on a sample o...The aim of this study is to identify and analyze the pattern of visibility of the main actors in the photographic coverage of drug trafficking in six of Mexico’s national newspapers. The study was based on a sample of 12,962,000 photographs published from 2006 to 2010. The images were processed by generating a codebook of key categories extracted from the informational context of drug trafficking and the war against drug trafficking. The technique used to explain the newspapers’ photographic coverage was the content analysis proposed by Johan Galtung in 1965, in its updated version of 2006. The limitations of the research are time constraints (only four years of President Felipe Calderón’s six-year term were analyzed) and information platforms (with the omission of online newspapers, supplements, and additional publications). The study offers an original analysis of the photographic coverage of drug trafficking in the Mexican press. The use of the Galtung Model reveals strong biases and imbalances in the coverage, with a clear tendency to defend the government’s position in the analyzed sample.展开更多
Cell therapy has been proposed as an alternative treatment for retinal diseases. Applications involving stem cells have shown that undifferentiated cells fail to engraft and cannot convert to retinal cells. However, p...Cell therapy has been proposed as an alternative treatment for retinal diseases. Applications involving stem cells have shown that undifferentiated cells fail to engraft and cannot convert to retinal cells. However, positive results have been reported for retinal precursor cells, suggesting that this approach is the best option. Unfortunately, the source of this cell type is controversial. Predifferentiated adult stem cells may provide an alternative source of cells. The present study proposes a sequential culture media aimed at inducing cells from this source into a preretinal-like lineage. Rat bone marrow stem cells were cultivated in a neuroinduction mix medium for 24 h. The sequence involves immunocytochemistry to detect nestin and tubulin III to demonstrate the cell’s neuronal lineage, followed by incubation in retinal-induction mixed medium for 24 h. RT-PCR was performed to detect expression of Brn3b, Pax6, THY1.1, Opn4, and Ath5 genes. Immunocytochemistry results showed increased expression of nestin and tubulin III after 24 h of incubation in the neuroinduction medium. RT-PCR showed slightly increased expression of Pax6, THY1.1, and Opn4 after 48 h of sequential incubation in the neuroinduction and predifferentiation media. Brn3b and Ath5 gene expression increased markedly. These results suggest that mesenchymal stem cells have a high predisposition to differentiate into preretinal-like cells with minimal time in culture. These cells may provide a viable alternative for restoring damaged retinas.展开更多
The use of stem cells has been proposed as an alternative treatment for certain neurodegenerative disorders. It has also been suggested that in the pre-differentiated state, stem cells might provide a better therapeut...The use of stem cells has been proposed as an alternative treatment for certain neurodegenerative disorders. It has also been suggested that in the pre-differentiated state, stem cells might provide a better therapeutic option than cells that are undifferentiated or fully differentiated. The purpose of this study was to develop a protocol aimed at reducing the incubation time required to induce the conversion of rat mesenchymal stem cells into immature dopaminergic neurons. Stem cells obtained from rat bone marrow were incubated in a control or induction media for 2-24 h. Cells incubated for 24 h in induction medium demonstrated an increase on the levels of the neuronal protein markers nestin, glial fibrillary acid protein, and β-tubulin III, as well as increases in the expression of Pax3, EN1, Thy1.1, and GEF10 genes. This manuscript presents evidence that adult mesenchymal cells are capable to respond, in a short time period, to a neuroinduction medium, and give raise to pre-differentiated neuron like cells representing an alternative for Parkinson disease cell therapy transplantation.展开更多
Stem cell therapy for cardiac infarct regeneration has been widely used in clinical research. Despite the fact that important advances in this field have been reached, the observed recovery does not demonstrate new ca...Stem cell therapy for cardiac infarct regeneration has been widely used in clinical research. Despite the fact that important advances in this field have been reached, the observed recovery does not demonstrate new cardiac muscle formation. Benefits have been observed due to an improvement in neovascularisation. The main objective of this study was to determine if pre-differentiated stem cells into cells of myocardic lineage are capable of engraftment in animal models with induced cardiac infarct and are capable of truly differentiating into myocardiocytes. Bone marrow rat stem cells were pre-differentiated with 5-AZ. After 4 weeks, pre-differentiated stem cells express muscarinic 1, 2 and β adrenergic 2 receptors. Also, proteins such as sarcomeric α-actin, cardiac myosin heavy chain, desmin and vimentin were detected by immunocytochemistry. Cells were transplanted intracardialy in an ischemic cardiac rat model. Pre-differentiated or non differentiated cells were transplanted after 4 weeks post infarct induction. Histopathology of the hearts was made 2 weeks after cell transplantation. Typical granulated tissue, scare formation and neovascularisation were observed in both groups. However, in those hearts from rats inoculated with pre-differentiated cells many appeared atypical and were α-actin sarcomeric positive. These events suggest that pre-differentiated cells conserve some muscle characteristic traits in situ that at least last for two weeks after transplantation.展开更多
Circulating CD133+ stem cells from the peripheral blood have been shown to be able to differentiate into numerous cell lineages. However, adults have only a small number of these circulating stem cells. The aim of the...Circulating CD133+ stem cells from the peripheral blood have been shown to be able to differentiate into numerous cell lineages. However, adults have only a small number of these circulating stem cells. The aim of the present study was to assess a new isolation and enrichment technique for CD133+ stem cells from peripheral blood with the use of Percoll density gradients. Our results demonstrated the presence of two large mononuclear bands when whole blood was centrifuged with 48% and 50% Percoll concentrations. Flow cytometric analysis (FACS) revealed a major CD133+ enrichment at the 48% Percoll concentration in one of the two bands. Further culture of these cells resulted in the formation of multiple colony-forming units. Our results suggest an advantage from using a simple Percoll gradient for successful CD133+ cell recovery, which could aid in differentiation and transplantation protocols.展开更多
In this work, for a control consumption-investment process with the discounted reward optimization criteria, a numerical estimate of the stability index is made. Using explicit formulas for the optimal stationary poli...In this work, for a control consumption-investment process with the discounted reward optimization criteria, a numerical estimate of the stability index is made. Using explicit formulas for the optimal stationary policies and for the value functions, the stability index is explicitly calculated and through statistical techniques its asymptotic behavior is investigated (using numerical experiments) when the discount coefficient approaches 1. The results obtained define the conditions under which an approximate optimal stationary policy can be used to control the original process.展开更多
文摘The use of carbon from waste biomass has the potential to eliminate the drawbacks of Li-S batteries and improve their overall performance.Chrome-tanned-leather-shavings(CTLS)are a readily available waste product that can be transformed into porous carbon.We prepared an ac-tivated carbon by microwave pyrolysis combined with KOH activator using the CTLS as starting materials.The carbon had a specific surface area of 556 m^(2)g^(-1) and a honeycomb-like structure.Two kinds of N-doped activated carbons were then synthesized by thermal decomposition of the activated carbon,either combined with urea,or impregnated with eth-anolamine.Both N-doped activated carbons have an in-creased number of nitrogen and amine surface groups.However,only the urea treatment was effective in improv-ing the initial capacity of the cell(1363 mAh g^(-1)),which is probably linked to the sorption of long-chain polysulfides.This investigation confirms that it is possible to use the thermal de-composition of urea to obtain carbon materials from CTLS for use as the sulfur-host cathode in Li-S batteries and improve their performance.A radial basis function neural network was fitted to provide statistical support for the experimental results,which confirmed the importance of the nitrogen content of the carbons in determining the discharge capacity of the cells.
基金This work was supported by the National Institutes of Health(R00CA201603,R21EB025270,R21EB026175,R01EB028143)the Brigham Research Institute.
文摘Paper devices have recently attracted considerable attention as a class of cost-effective cell culture substrates for various biomedical applications.The paper biomaterial can be used to partially mimic the in vivo cell microenvironments mainly due to its natural three-dimensional characteristic.The paper-based devices provide precise control over their structures as well as cell distributions,allowing recapitulation of certain interactions between the cells and the extracellular matrix.These features have shown great potential for the development of normal and diseased human tissue models.In this review,we discuss the fabrication of paper-based devices for in vitro tissue modeling,as well as the applications of these devices toward drug screening and personalized medicine.It is believed that paper as a biomaterial will play an essential role in the field of tissue model engineering due to its unique performances,such as good biocompatibility,eco-friendliness,cost-effectiveness,and amenability to various biodesign and manufacturing needs.
文摘Segmenting vegetation in color images is a complex task, especially when the background and lighting conditions of the environment are uncontrolled. This paper proposes a vegetation segmentation algorithm that combines a supervised and an unsupervised learning method to segment healthy and diseased plant images from the background. During the training stage, a Self-Organizing Map (SOM) neural network is applied to create different color groups from a set of images containing vegetation, acquired from a tomato greenhouse. The color groups are labeled as vegetation and non-vegetation and then used to create two color histogram models corresponding to vegetation and non-vegetation. In the online mode, input images are segmented by a Bayesian classifier using the two histogram models. This algorithm has provided a qualitatively better segmentation rate of images containing plants’ foliage in uncontrolled environments than the segmentation rate obtained by a color index technique, resulting in the elimination of the background and the preservation of important color information. This segmentation method will be applied in disease diagnosis of tomato plants in greenhouses as future work.
基金supported by the National Science and Technology Council of Mexico(CONACYT)(No.192118)
文摘The production of thermostable laccases from a native strain of the white-rot fungus Pycnoporus sanguineus isolated in Mexico was enhanced by testing different media and a combination of inducers including copper sulfate（CuSO4）.The best conditions obtained from screening experiments in shaken flasks using tomato juice,CuSO4,and soybean oil were integrated in an experimental design.Enhanced levels of tomato juice as the medium,CuSO4and soybean oil as inducers（36.8%（v/v）,3 mmol/L,and 1%（v/v）,respectively） were determined for 10 L stirred tank bioreactor runs.This combination resulted in laccase titer of 143000 IU/L（2,2＇-azino-bis（3-ethylbenzthiazoline-6- sulfonic acid）,pH 3.0）,which represents the highest activity so far reported for P.sanguineus in a 10-L fermentor.Other interesting media resulting from the screening included glucose-bactopeptone which increased laccase activity up to 20000 IU/L,whereas the inducers Acid Blue 62 and Reactive Blue 19 enhanced enzyme production in this medium 10 times.Based on a partial characterization,the laccases of this strain are especially promising in terms of thermostability（half-life of 6.1 h at 60 °C） and activity titers.
文摘A simple and rapid Fourier Transform infrared (FTIR) spectroscopy method was developed to determine the main essential oil components (carvacrol, thymol and p-cymene) in the antimicrobial LDPE films incorporated with oregano (Origanum vulgare) and thyme (Thymus vulgaris) essential oils. The ATR-FTIR spectrum of pure active components (carvacrol, thymol and p-cymene) was characterized, and the ranges between 1125 cm-1 - 1095 cm-1, 1170 cm-1 - 1140 cm-1 and 1050 cm-1 - 1017 cm-1 were respectively used for quantitative estimation. Partial least square (PLS) analysis was used for quantitative analysis. FTIR spectroscopy with chemometrics, using the PLS-1st derivative spectra, could predict the content of active compounds accurate to an r2 greater than 0.99 and a standard error of prediction (SEP) less than 0.7. The developed method was successfully applied to predict the concentration of active compounds: carvacrol, thymol and p-cymene in oregano and thyme essential oils with results compared to those of the GC-MS method. The described non-destructive method can be applied in the industry instead of extraction, distillation and blend processes of the mentioned essential oils and can be extended to detect the content of carvacrol, thymol and p-cymene in active packaging and other commercial products.
文摘BACKGROUND Fibroadenoma(FA)is the most common tumor found in young women,although it can occur in any age group.Ductal carcinoma in situ(DCIS)that is confined in a FA is rare;it is most frequently reported as an incidental finding.CASE SUMMARY We report a case of DCIS within a FA in a 46-year-old female without cancerrelated personal and family histories.The patient was diagnosed with a breast conglomerate of nodules and was followed for 1 year.In the current control image study,we found suspicious microcalcification,as a new finding,within one of the nodules.Consequently,a core biopsy of the tumor,which appeared hypoechoic,oval,and circumscribed,was performed.The pathological diagnosis was ductal carcinoma in situ within a fibroepithelial lesion.The patient underwent breastconserving surgery and received radiotherapy as well as endocrine therapy(tamoxifen).CONCLUSION We recommend a multidisciplinary approach for adequate treatment and followup.
文摘Fatty liver has been present in the lives of patients and physicians for almost two centuries.Vast knowledge has been generated regarding its etiology and consequences,although a long path seeking novel and innovative diagnostic biomarkers for nonalcoholic fatty liver disease(NAFLD)and nonalcoholic steatohepatitis(NASH)is still envisioned.On the one hand,proteomics and lipidomics have emerged as potential noninvasive resources for NAFLD diagnosis.In contrast,metabolomics has been able to distinguish between NAFLD and NASH,even detecting degrees of fibrosis.On the other hand,genetic and epigenetic markers have been useful in monitoring disease progression,eventually functioning as target therapies.Other markers involved in immune dysregulation,oxidative stress,and inflammation are involved in the instauration and evolution of the disease.Finally,the fascinating gut microbiome is significantly involved in NAFLD and NASH.This review presents state-of-the-art biomarkers related to NAFLD and NASH and new promises that could eventually be positioned as diagnostic resources for this disease.As is evident,despite great advances in studying these biomarkers,there is still a long path before they translate into clinical benefits.
文摘The highly competitive offer of medical training programs and schools,globalization and constant mobility of physicians and medical students(MS),and the commitment to society to deliver competent physicians,demands the definition of performance standards.This would allow to make their performances comparable no matter where they studied or which textbook did they used as reference,to have evaluation mechanisms that guarantee mastery of the integral evaluation of the performance.Assessment has been the key in the teaching-learning process as this obtains a formative and summative element,at different moments,from the extent to which the students have acquired knowledge,skills and attitudes.The progress of the learner must be enhanced with effective feedback on their performance and self-direction of the results obtained in each of the mechanisms established.If,traditionally,this has been considered as the accreditation of compliance with a standard,the evaluation also functions in an integral way as a formative process that identifies advances and deficiencies in the training of residents that allows the definition of actions and strategies for improving the operation of the programs.Different assessment mechanisms are associated with the areas of competence domain,some of the most common tools are:theoretical exams,checklists and rubrics,portfolio,projects and challenges.However,the importance of defining standards which are perceived as fair and designed according to the learning objectives remains a priority to guarantee the credibility of the evaluation agencies and institutions.Some strategies to assure credibility include the involvement of expert and trained evaluators,allowing the process to be carried out with transparency and diligence,and the principles employed should be supported by educational research.
文摘A rapid, cost effective and reliable analytical method was developed and validated for the simultaneous determination of four estrogens (17 β-estradiol, 17 α-ethinylestradiol, estrone, and estriol) in compost samples from the biodegradation of biological infectious hazardous wastes. Ultrasonic solvent extraction, using methanol as extraction solvent, coupled with SPE clean-up, using cartridges HLB 60 mg - 6 ml Supelco®<sup></sup> and acetonitrile for reconstitution of eluents, was used for the simultaneous extraction of the four estrogens. Mean recoveries in the range of 98% - 107% were obtained. All compounds were separated in a single gradient run by UHPLC Kinetex<sup>TM</sup> 2.6 μm XB-C18 100 ÅLC (50 × 4.6 mm) column. Analytes were detected via multiple reaction monitoring (MRM) using an AB SCIEX API-5000TM triple quadrupole (Applied Biosystems/MDS SCIEX) with electrospray ionization in negative mode. Isocratic mobile phase of Water:ACN (50:50) resulted to be the optimum. Limits of detection and quantification were on the order of 0.66 ng·g<sup>-1</sup> and 2 ng·g<sup>-1</sup> for all the estrogens. These limits were lower than most of the values reported in the literature for similar matrices. Suitable level of linearity, good repeatability and reproducibility with coefficients of variation is lower than 11.7%, 6.8% and 8.3%, respectively.
基金supported by the National Polytechnic Institute(SIP-20221151,SIP-20220916)。
文摘This paper addresses the design of an exponential function-based learning law for artificial neural networks(ANNs)with continuous dynamics.The ANN structure is used to obtain a non-parametric model of systems with uncertainties,which are described by a set of nonlinear ordinary differential equations.Two novel adaptive algorithms with predefined exponential convergence rate adjust the weights of the ANN.The first algorithm includes an adaptive gain depending on the identification error which accelerated the convergence of the weights and promotes a faster convergence between the states of the uncertain system and the trajectories of the neural identifier.The second approach uses a time-dependent sigmoidal gain that forces the convergence of the identification error to an invariant set characterized by an ellipsoid.The generalized volume of this ellipsoid depends on the upper bounds of uncertainties,perturbations and modeling errors.The application of the invariant ellipsoid method yields to obtain an algorithm to reduce the volume of the convergence region for the identification error.Both adaptive algorithms are derived from the application of a non-standard exponential dependent function and an associated controlled Lyapunov function.Numerical examples demonstrate the improvements enforced by the algorithms introduced in this study by comparing the convergence settings concerning classical schemes with non-exponential continuous learning methods.The proposed identifiers overcome the results of the classical identifier achieving a faster convergence to an invariant set of smaller dimensions.
基金supported by the Coordinación de la Investigación Científica UMSNH.E.C.-F.and J.A.-R.were fellows of CONACYT-México.
文摘The potential of Plant Growth Promoting Rhizobacteria(PGPR)has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield.A.brasilense produces a wide variety of molecules,including the natural auxin indole-3-acetic acid(IAA),as well as other phytoregulators.However,several studies have suggested that auxin induces changes in plant development during their interaction with the bacteria.The effects of A.brasilense Sp245 on the development of Arabidopsis thaliana root were investigated to help explain the molecular basis of the interaction.The results obtained showed a decrease in primary root length from the first day and remained so throughout the exposure,accompanied by a stimulation of initiation and maturation of lateral root primordia and an increase of lateral roots.An enhanced auxin response was evident in the vascular tissue and lateral root meristems of inoculated plants.However,after five days of bacterization,the response disappeared in the primary root meristems.The role of polar auxin transport(PAT)in auxins relocation involved the PGP1,AXR4-1,and BEN2 proteins,which apparently mediated A.brasilense-induced root branching of Arabidopsis seedlings.
文摘Torin 1 is an ATP-competitive TOR inhibitor which inhibits the signaling of TOR and S6K kinase in mammals and plants.The objective of this research is to determine the effect of Torin 1 in a relatively simple and homogeneous plant system such as the NT-1 tobacco suspension cell cultures.Cultures of NT-1 cells were tested with 5,50,150 and 250 nM of Torin 1.During kinetics growth of NT-1 tobacco suspension cell cultures,150 and 250 nM Torin 1 inhibits the early growth and later enhanced the cellular proliferation during exponential growth by means of an increased expression of E2F1 and cyclin B.Furthermore,Torin 1 stimulates the growth of NT-1 cells during log phase with small shaped cell,characteristic of tobacco suspension cell cultures with high mitotic activity.
文摘In this paper we study a continuous time random walk in the line with two boundaries [a,b], a < b. The particle can move in any of two directions with different velocities v1 and v2. We consider a special type of boundary which can trap the particle for a random time. We found closed-form expressions for the stationary distribution of the position of the particle not only for the alternating Markov process but also for a broad class of semi-Markov processes.
文摘Hand injuries are a frequent problem in actual society.These are often caused while working or exercising,but simple everyday activities can also be the cause.The most common injuries are those related to soft tissue;specifically,muscles,tendons,and ligaments.To improve therapy results and reduce its cost and needed time,a self-rehabilitation system for soft tissue injuries in the hands was developed.The proposed system is meant to be implemented on Smart TVs and can be used in the home of the injured people.To identify the most common movements of the injured limbs,and design proper therapies to be displayed by the system,an exoskeleton prototype which supports four degrees of freedom of the hand was constructed.We examined scenarios to provide services for individuals and created a scenario-based prototype,which was tested by an exercise therapist to verify compliance with the requirements of users.
文摘The aim of this study is to identify and analyze the pattern of visibility of the main actors in the photographic coverage of drug trafficking in six of Mexico’s national newspapers. The study was based on a sample of 12,962,000 photographs published from 2006 to 2010. The images were processed by generating a codebook of key categories extracted from the informational context of drug trafficking and the war against drug trafficking. The technique used to explain the newspapers’ photographic coverage was the content analysis proposed by Johan Galtung in 1965, in its updated version of 2006. The limitations of the research are time constraints (only four years of President Felipe Calderón’s six-year term were analyzed) and information platforms (with the omission of online newspapers, supplements, and additional publications). The study offers an original analysis of the photographic coverage of drug trafficking in the Mexican press. The use of the Galtung Model reveals strong biases and imbalances in the coverage, with a clear tendency to defend the government’s position in the analyzed sample.
文摘Cell therapy has been proposed as an alternative treatment for retinal diseases. Applications involving stem cells have shown that undifferentiated cells fail to engraft and cannot convert to retinal cells. However, positive results have been reported for retinal precursor cells, suggesting that this approach is the best option. Unfortunately, the source of this cell type is controversial. Predifferentiated adult stem cells may provide an alternative source of cells. The present study proposes a sequential culture media aimed at inducing cells from this source into a preretinal-like lineage. Rat bone marrow stem cells were cultivated in a neuroinduction mix medium for 24 h. The sequence involves immunocytochemistry to detect nestin and tubulin III to demonstrate the cell’s neuronal lineage, followed by incubation in retinal-induction mixed medium for 24 h. RT-PCR was performed to detect expression of Brn3b, Pax6, THY1.1, Opn4, and Ath5 genes. Immunocytochemistry results showed increased expression of nestin and tubulin III after 24 h of incubation in the neuroinduction medium. RT-PCR showed slightly increased expression of Pax6, THY1.1, and Opn4 after 48 h of sequential incubation in the neuroinduction and predifferentiation media. Brn3b and Ath5 gene expression increased markedly. These results suggest that mesenchymal stem cells have a high predisposition to differentiate into preretinal-like cells with minimal time in culture. These cells may provide a viable alternative for restoring damaged retinas.
文摘The use of stem cells has been proposed as an alternative treatment for certain neurodegenerative disorders. It has also been suggested that in the pre-differentiated state, stem cells might provide a better therapeutic option than cells that are undifferentiated or fully differentiated. The purpose of this study was to develop a protocol aimed at reducing the incubation time required to induce the conversion of rat mesenchymal stem cells into immature dopaminergic neurons. Stem cells obtained from rat bone marrow were incubated in a control or induction media for 2-24 h. Cells incubated for 24 h in induction medium demonstrated an increase on the levels of the neuronal protein markers nestin, glial fibrillary acid protein, and β-tubulin III, as well as increases in the expression of Pax3, EN1, Thy1.1, and GEF10 genes. This manuscript presents evidence that adult mesenchymal cells are capable to respond, in a short time period, to a neuroinduction medium, and give raise to pre-differentiated neuron like cells representing an alternative for Parkinson disease cell therapy transplantation.
文摘Stem cell therapy for cardiac infarct regeneration has been widely used in clinical research. Despite the fact that important advances in this field have been reached, the observed recovery does not demonstrate new cardiac muscle formation. Benefits have been observed due to an improvement in neovascularisation. The main objective of this study was to determine if pre-differentiated stem cells into cells of myocardic lineage are capable of engraftment in animal models with induced cardiac infarct and are capable of truly differentiating into myocardiocytes. Bone marrow rat stem cells were pre-differentiated with 5-AZ. After 4 weeks, pre-differentiated stem cells express muscarinic 1, 2 and β adrenergic 2 receptors. Also, proteins such as sarcomeric α-actin, cardiac myosin heavy chain, desmin and vimentin were detected by immunocytochemistry. Cells were transplanted intracardialy in an ischemic cardiac rat model. Pre-differentiated or non differentiated cells were transplanted after 4 weeks post infarct induction. Histopathology of the hearts was made 2 weeks after cell transplantation. Typical granulated tissue, scare formation and neovascularisation were observed in both groups. However, in those hearts from rats inoculated with pre-differentiated cells many appeared atypical and were α-actin sarcomeric positive. These events suggest that pre-differentiated cells conserve some muscle characteristic traits in situ that at least last for two weeks after transplantation.
文摘Circulating CD133+ stem cells from the peripheral blood have been shown to be able to differentiate into numerous cell lineages. However, adults have only a small number of these circulating stem cells. The aim of the present study was to assess a new isolation and enrichment technique for CD133+ stem cells from peripheral blood with the use of Percoll density gradients. Our results demonstrated the presence of two large mononuclear bands when whole blood was centrifuged with 48% and 50% Percoll concentrations. Flow cytometric analysis (FACS) revealed a major CD133+ enrichment at the 48% Percoll concentration in one of the two bands. Further culture of these cells resulted in the formation of multiple colony-forming units. Our results suggest an advantage from using a simple Percoll gradient for successful CD133+ cell recovery, which could aid in differentiation and transplantation protocols.
文摘In this work, for a control consumption-investment process with the discounted reward optimization criteria, a numerical estimate of the stability index is made. Using explicit formulas for the optimal stationary policies and for the value functions, the stability index is explicitly calculated and through statistical techniques its asymptotic behavior is investigated (using numerical experiments) when the discount coefficient approaches 1. The results obtained define the conditions under which an approximate optimal stationary policy can be used to control the original process.
