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Constitutive expression of the active fragment of human vasostatin Vs30 in Pichia pastoris SMD1168H
Get PDF"Vasostatin 30 (Vs30) is an active fragment derived from the N-terminal region (135–164 aa) of human calreticulin and has the ability to inhibit angiogenesis. In this work, the expression of Vs30 was performed using a protease-deficient strain of the methylotrophic yeast Pichia pastoris. The vs30 gene was optimized for P. pastoris preferential codon usage and inserted into constitutive expression vector pGAPZ?A. In addition, a plasmid with four copies of the expression cassette was obtained and transformed into P. pastoris. The flask fermentation conditions were: culture volume of 25 mL in 250 mL baffled flasks at 28 °C, pH 6 and harvest time of 48 h. Up to 21.07 mg/L Vs30 were attained and purified by ultrafiltration with a 30-kDa cut-off membrane and the recovery was 49.7%. Bioactivity of Vs30 was confirmed by the inhibition of cell proliferation, as well as the inhibition of the capillary-like structures formation of EA.hy926 cells in vitro. This work constitutes the first report on the expression of Vs30 in Pichia pastoris using a constitutive promoter and multi-copy approach such as strategies to improve the recombinant Vs30 expression.
High-pressure synthesis of β-Ir4B5 and determination of the compressibility of various iridium borides
Get PDF"A new iridium boride, beta-Ir4B5, was synthesized under high-pressure/high-temperature conditions of 10.5 GPa and 1500 degrees C in a multianvil press with a Walker-type module. The new modification beta-Ir4B5 crystallizes in a new structure type in the orthorhombic space group Pnma (no. 62) with the lattice parameters a = 10.772(2) angstrom, b = 2.844(1) angstrom, and c = 6.052(2) angstrom with R1 = 0.0286, wR2 = 0.0642 (all data), and Z = 2. The structure was determined by single-crystal X-ray and neutron powder diffraction on samples enriched in B-11. The compound is built up by an alternating stacking of boron and iridium layers with the sequence ABA'B'. Additionally, microcalorimetry, hardness, and compressibility measurements of the binary iridium borides alpha-Ir4B5, beta-Ir4B5, Ir5B4, hexagonal Ir4B3-x and orthorhombic Ir4B3-x were carried out and theoretical investigations based on density function theory (DFT) were employed to complement a comprehensive evaluation of structure-property relations. The incorporation of boron into the structures does not enhance the compressibility but leads to a significant reduction of the bulk moduli and elastic constants in comparison to elemental iridium.
Timbe (Acaciella angustissima) pods extracts reduce the levels of glucose, insulin and improved physiological parameters, hypolipidemic effect, oxidative stress and renal damage in streptozotocin-induced diabetic rats
Get PDF"In Mexico one in 14 deaths are caused by diabetes mellitus (DM) or by the macro and microvascular disorders derived from it. A continuous hyperglycemic state is characteristic of DM, resulting from a sustained state of insulin resistance and/or a dysfunction of ?-pancreatic cells. Acaciella angustissima is a little studied species showing a significant antioxidant activity that can be used as treatment of this disease or preventive against the complications. The objective of this study was to explore the effect of oral administration of A. angustissima methanol extract on physiological parameters of streptozotocin-induced diabetic rats. The results indicated a significant reduction in blood glucose levels, an increase in serum insulin concentration, a decrease in lipid levels and an improvement in the parameters of kidney damage by applying a concentration of 100 mg/Kg B.W. However, glucose uptake activity was not observed in the adipocyte assay. Moreover, the extract of A. angustissima displayed potential for the complementary treatment of diabetes and its complications likely due to the presence of bioactive compounds such as protocatechuic acid. This study demonstrated that methanol extract of Acacciella angustissima has an antidiabetic effect by reducing the levels of glucose, insulin and improved physiological parameters, hypolipidemic effect, oxidative stress and renal damage in diabetic rats.
Chemical stability of superhard rhenium diboride at oxygen and moisture ambient environmental conditions prepared by mechanical milling
Get PDF"In this study, rhenium diboride (ReB2) was obtained by mechanosynthesis at 640 minutes of milling. The obtained ReB2 was stored at oxygen and moisture ambient environmental conditions to know the chemical stability. The results indicate that ReB2 is totally decomposed at oxygen and moisture ambient environmental conditions. Furthermore, the X-ray diffraction (XRD) analysis of ReB2 samples after 26 months of storage shows that the final products of degradation are HReO4 (liquid), H3BO3, HBO2, and ReO3. Finally, a schematic diagram of the degradation sequence of ReB2 at oxygen and moisture ambient environmental conditions is proposed and validated with a thermodynamic analysis.
Bacterial wilt and canker of tomato: fundamentals of a complex biological system
Get PDF"Tomato (Solanum lycopersicum) is well-known as a model for study of plant–pathogen interactions, since it is a crop of global relevance and susceptible to multiple bacterial, fungal, viral and nematode pathogens. Among bacterial phytopathogens, the actinomycete Clavibacter michiganensis subsp. michiganensis (Cmm) is the causal agent of bacterial wilt and canker of tomato, considered a quarantine disease at international level. The tomato–Cmm interaction has been studied to decipher the pathogenicity mechanisms in Cmm, susceptibility mechanisms in tomato, molecular basis of resistance to Cmm in wild species relative to domesticated tomato, and the level of genetic variability in Cmm. The objective of this review is to discuss recent advances in tomato–Cmm compatible interaction, which can be integrated for application in early diagnosis and biological control of bacterial wilt and canker of tomato. Further study of plant–microorganism interactions is a promising field for improvements in tomato pathogen resistance.
Reappraisal of Los Humeros Volcanic Complex by New U/Th Zircon and 40Ar/39Ar Dating: Implications for Greater Geothermal Potential
Get PDF"Longevity and size of magmatic systems are fundamental factors for assessing the potential of a geothermal field. At Los Humeros volcanic complex (LHVC), the first caldera-forming event was reported at 46040 ka. New zircon U/Th and plagioclase Ar-40/Ar-39 dates of pre-, syn- and postcaldera volcanics allow a reappraisal of the evolution of the geothermally active LHVC. The age of the voluminous Xaltipan ignimbrite (115 km(3) dense rock equivalent [DRE]) associated with the formation of the Los Humeros caldera is now constrained by two geochronometers (zircon U/Th and plagioclase Ar-40/Ar-39 dating) to 1644.2 ka, which postdates a long episode of precaldera volcanism (rhyolitic domes), the oldest age of which is 693.01.9 ka (Ar-40/Ar-39). The inferred short residence time (around 5 ka) for the paroxysmal Xaltipan ignimbrite is indicative of rapid assembly of a large magma body and rejuvenation of the system due to recurrent recharge magmas, as it has been occurred in some other large magmatic systems. Younger ages than previously believed have been obtained also for the other voluminous explosive phases of the Faby fall tuff at approximate to 70 ka and the second caldera-forming Zaragoza ignimbrite with 15 km(3) DRE, which erupted immediately after. Thus, the time interval that separates the two caldera-forming episodes at Los Humeros is only 94 kyr, which is a much shorter interval than suggested by previous K-Ar dates (410 kyr). This temporal proximity allows us to propose a caldera stage encompassing the Xaltipan and the Zaragoza ignimbrites, followed by emplacement at 44.81.7 ka of rhyolitic magmas interpreted to represent a postcaldera, resurgent stage. Rhyolitic eruptions have also occurred during the Holocene (approximate to 1,200 km(3)) and these new ages indicating much younger caldera-forming volcanism than previously believed are fundamental factors in the application of classical conductive models of heat resource, enhancing the heat production capacity and favor a higher geothermal potential.
Plain Language Summary More recent ages obtained for Los Humeros volcano may increase the heat capacity of the magmatic chamber at depth, providing more favorable conditions for the development of the geothermal energy.
Distributed control for consensus on leader-followers proximity graphs
Get PDF"We propose two distributed controller solutions to the leader-followers consensus problem on inertial multiagent systems with guarantee connectivity preservation based on artificial potential functions. On the first one, we consider a virtual leader with constant velocity, in this case consensus is defined as a position reference to be tracked. On the second, the leader’s velocity is time-varying. In both cases, we consider that only a subset of agents have access to leader’s state information. Effectiveness of proposed controllers is illustrated with numerical simulations.
Molecular detection of four common Candida species from blood cultures
No full text"En este trabajo empleamos oligonucleótidos diseñados en el IPICYT para amplificar secuencias genómicas específicas de las cuatro especies principales causantes de candidemia. Realizamos la identificación de 194 aislados de 89 pacientes atendidos en el INCMNSZ y el INCAN. Encontramos que el 39.7% (n=33) de los casos correspondió a C. albicans, el 23.6% (n=21) a C. glabrata, el 19.1% a C. tropicalis (n=17) y el 12.4% C. parapsilosis (n=11). Además, utilizamos el mismo método para identificar las especies de Candida a partir de hemocultivos positivos para Candida spp. Mediante el protocolo descrito por Ausubel (FP) para la extracción de DNA genómico logramos detectar hasta 105 células/mL con la mayoría de los oligonucleótidos empleados, con una sensibilidad y especificidad del 100%. También logramos detectar hasta 104 células de C. tropicalis y C. parapsilosis y 105 células de C. glabrata y C. albicans a partir de muestras de sangre directamente sin cultivar. Realizamos un análisis de relación genética en 39 aislados de C. glabrata de 15 pacientes con el método RAPD-PCR. Encontramos seis genotipos distintos (I-VI), de los cuales el genotipo I fue el más prevalente pues se encontró en aislados de seis pacientes. Todos los aislados del mismo paciente mostraron el mismo genotipo. Finalmente, analizamos la sensibilidad a fluconazol (FLC) donde el 51.3% (19/37) de los aislados de C. glabrata (algunos provenientes de muestras consecutivas del mismo paciente) fueron resistentes de manera dosis-dependiente a FLC, el 45.9% (17/37) fueron sensibles y solo uno fue resistente a FLC. Además, dos aislados mostraron menor sensibilidad a FLC que otros aislados del mismo paciente. En conclusión, desarrollamos un método de PCR de punto final rápido, altamente sensible y específico para la detección de las cuatro principales especies del género Candida que causan candidemia en hemocultivos y en sangre. En el análisis de la población de C. glabrata observamos correlación genotípica entre los aislados de diferentes pacientes y que algunas cepas tienden a desarrollar resistencia a FLC.""In this study we used oligonucleotides designed at IPICYT to amplify speciesspecific
genomic sequences of the four main species causing candidemia. We
determined the distribution of Candida species in 194 clinical isolates from 89
patients from the INCMNSZ and the INCAN. We found that C. albicans
corresponds to 39.7% (n=33) of the cases, C. glabrata to 23.6% (n=21), C.
tropicalis to 19.1% (n=17) and C. parapsilosis to 12.4% (n=11).
We used a method described by Ausubel (FP) for the extraction of genomic DNA
from blood cultures positive for Candida spp. With this method we detected 105
cells/mL with a sensitivity and specificity of 100%. We also detected 105 cells of C.
glabrata and C. albicans and 104 cells of C. tropicalis and C. parapsilosis directly
from blood samples.
We then analyzed genetic relatedness using RAPD-PCR analysis on 39 C.
glabrata isolates from 15 different patients. We found six different genotypes;
genotype I was the most prevalent since it was found in clinical isolates from six
different patients, and some genotypes were only found in one patient. All the
isolates from the same patient showed the same genotype.
Finally, we found that 51.3% 19/37) of the C. glabrata isolates were Fluconazole
(FLC) resistant in a dose-dependent manner (FLCdd), 45.9% were sensitive to FLC
and only one isolate was FLC resistant. In addition, two isolates displayed a
decrease in sensitivity to FLC compared to the other isolates from the same
patient.
In conclusion, we developed a fast, highly sensitive and specific PCR method for
the detection of the four main Candida species that cause candidemia both, in
blood cultures and whole blood. Genetic analysis by RAPD-PCR of C. glabrata
isolates we observed genotypic relationship between isolates from different
patients. In addition, we found that and that some isolates can develop resistance
to FLC.
Regulación por fijación en redes de modelos neuronales linealmente acoplados
Get PDF"En la vida real existen muchos sistemas complejos de diferente naturaleza ya sean biológicos,
físicos, sociales o tecnológicos; los cuales pueden ser representados matemáticamente
como grafos donde los nodos son sistemas dinámicos y los enlaces describen la forma en que
interactúan para dar al sistema sus características y funcionalidad. A este modelo usualmente
se le llama red dinámica compleja ya que se caracteriza por buscar capturar la complejidad
estructural de las interacciones y la dinámica de los nodos que conforman al sistema original.
Uno de los aspectos más interesantes del estudio de redes dinámicas complejas es determinar
su comportamiento colectivo, es decir, establecer la forma en que la evolución dinámica de
sus nodos genera un comportamiento auto organizado. Un fenómeno básico que se presenta
en este tipo de sistemas es el surgimiento de comportamiento sincronizado, es decir, que los
nodos de la red evolucionan coordinados en el tiempo. En general, este tipo de evolución
dinámica al unísono no es necesariamente estable. En este caso, se pueden diseñar controladores
para imponer un comportamiento deseado en la red. La naturaleza de las conexiones
en la red permiten utilizar una metodología de diseño llamada control por fijación, en la cual
una acción de control por retroalimentación local se aplica solo a un número muy reducido
de nodos y se logra el objetivo de control en toda la red, ya sea este un estado estacionario o
seguir una referencia dada.
En este trabajo de tesis nos enfocamos en los problemas de sincronización y control por
fijación cuando los nodos son funciones matemáticas de modelos neuronales, específicamente
neuronas tipo Hindmarsh-Rose, los cuales describen matemáticamente una aproximación
al comportamiento eléctrico de la neurona. En particular, reproducen los ciclos de disparos
de picos característicos del comportamiento neuronal. Nuestro modelo de la red neuronal es
una red compleja donde las neuronas están acopladas solamente en forma eléctrica. Para este
modelo de la red neuronal establecemos condiciones para el surgimiento de sincronización
idéntica cuando las conexiones son uniformes y también para el caso en que las conexiones
tienen pesos. Así mismo, para ambos tipos de conexión proponemos controladores locales
basados en la estrategia de control por fijación para imponer un comportamiento de punto de
equilibrio estable en toda la red de neuronas.""In real life there are many complex systems of different natures, they can be biological,
physical, social or technological; which can be represented mathematically as graphs where
the nodes are dynamical systems and the links describe the form in which they interact to give
the system its characteristics and functionality. These models are usually called complex
dynamical networks since they are characterized by the aim to capture the structural complexity
of the interactions and the dynamics of the nodes that constitute the original complex
system.
One of the most interesting aspects of the study of complex dynamical networks is determining
its collective behavior, that is, establishing the way in which the nodes evolve
dynamically to generate an autoorganized behavior. A basic phenomenon that is present in
these type of systems is the emergence of synchronized behavior, that is, the nodes in the
network evolve coordinated in time.
In general, this type of dynamical evolution at unison is not necessarily stable. In that case,
controllers can be designed to impose the desired behavior on the network. The connected
nature of the system allows us to use the pinning control strategy to design the controllers.
Using this approach a local feedback control action can be applied only to a reduced number
of nodes to achieve the control objective for the entire network, the desired behavior can be
a fixed point or a given time-varying reference.
In this thesis, we focus on the synchronization and pinning control problems when the
nodes are neural models, specifically Hindmarsh-Rose type neurons, which describes mathematically
an approximation to the electrical behavior of a neuron. In particular, it reproduces
the spike bursting cycles that characterize the dynamics of a neuron. Our model of the neural
network is a complex dynamical network which is only coupled electrically. For these model
of the neural network, we establish conditions for the emergence of identical synchronization
when the connections are uniform and also when the connections have weights. Also,
for both types of connection, we propose local controllers based on the pinning strategy to
impose a stable fixed point behavior to the entire network of neurons.
Distribución espacio-temporal de radón en interiores urbanos de San Luis Potosí
Get PDF"El Radón es un gas noble el cual no reacciona con ningún otro elemento y es de origen natural, se encuentra en el suelo, rocas y en el agua, el cual asciende a través del basamento por fallas o fracturas hasta llegar al aire que respiramos. Es incoloro, inodoro e insípido y procede de la desintegración radiactiva del Uranio 238. Es importante mencionar que la unidad de medida del radón es en Bq/m3, es decir, el número de desintegraciones que se producen en 1 segundo en un metro cubico. La presente investigación expone los resultados obtenidos después de haber realizado un muestreo en interiores urbanos de 50 puntos seleccionados al azar dentro de la “Zona Urbana de San Luis Potosí” (ZUSLP) y 29 muestreos en subsuelo correspondientes a áreas cercanas (patio, calle, jardín, etc.) de algunos muestreos realizados en interiores, durante el periodo de febrero a octubre de 2017. Los puntos muestreados fueron realizados en interiores de casas, escuelas y lugares de trabajo, así como en subsuelo. En base a las concentraciones obtenidas en los 50 muestreos, se concluye que: Las concentraciones altas de radón 222 en interiores dentro de la ZUSLP, dependen principalmente al tipo de estructura de la edificación, ventilación y material de construcción. Sin embargo, el tipo de subsuelo del cual está constituida la ZUSLP, aluvión, coluvión, material de relleno, etc., no es un factor importante que determine concentraciones altas en interiores para este estudio. Con estos datos se creó el “Mapa de riesgo por radiactividad de radón en interiores urbanos de San Luis Potosí”. Comienza con una revisión estadística que permite ver el grado de cumplimiento de los niveles de radón con respecto al límite permisible, en base a la recomendación realizada
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por la Agencia de Protección Ambiental (EPA) de Estados Unidos, la cual establece un máximo permisible de 148 Bq/m3 de promedio anual. La investigación se encuentra estructurada en 5 capítulos. Dichos capítulos comienzan con una breve introducción sobre que es el radón, cuáles son sus características de transportación y que es lo que lo hace dañino para la salud. Después se desarrollará el tema para la explicación de las características del subsuelo y el porqué de algunas zonas con mayores niveles de concentración en la zona urbana de San Luis Potosí. Esto para poder tomar medidas preventivas en las zonas que el radón se encuentre encima de los límites permisibles y evitar daños a la salud de la población.""The radón is a noble gas which does not react with any other element and it is of natural origin, it is found in soil, rocks and water, which rises through the basement to faults or fractures until reaching the air we breathe. It is colorless, odorless and insipid and comes from the radioactive decay of Uranium 238. It is important to mention that the radon unit of measurement is Bq/m3, that is, the number of disintegrations that occur in 1 second in a cubic meter. The present investigation exposes the results obtained after having made a sample in urban interiors of 50 randomly selected points within the "Urban Zone of San Luis Potosí" (ZUSLP) and 29 subsoil samples corresponding to nearby areas (yard, street, garden, etc.) of some samples taken indoors, during the period from February to October 2017. The sampled points were made inside homes, schools and workplaces, as well as in the subsoil. Based on the concentrations obtained in the 50 samplings, it is concluded that: The high concentrations of radon 222 in interiors inside the ZUSLP, depend mainly on the type of structure of the building, ventilation and construction material. However, the type of subsoil of which the ZUSLP, alluvium, colluvium, filling material is constituted, etc., is not an important factor that determines high indoor concentrations for this study. With these data, the "Radon risk map of radón in urban interiors of San Luis Potosí" was created. Begins with a statistical review that allows to see the degree of compliance of the radon levels with respect to the permissible limit, based on the recommendation made by the Environmental Protection Agency (EPA) of the United States, which establishes an allowable maximum of 148 Bq/m3 annual average. The investigation is structured
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in 5 chapters. These chapters begin with a brief introduction about what radon is, what are its transportation characteristics and what makes it harmful to health. Later the subject will be developed for the explanation of the characteristics of the subsoil and the reason of some areas with higher levels of concentration in the urban area of San Luis Potosí. This is to be able to take preventive measures in areas where radon is above the permissible limits and avoid damage to the health of the population."Agradecimientos al IPICYT Y CONACY