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Microbial recovery of metallic nanoparticles from industrial wastes and their environmental applications


"In recent years, metallic nanoparticles (NPs) have been produced by biological methods using bacteria and have been used with remarkable environmental applications. This paper emphasizes the basic aspects of microbial synthesis of metallic nanoparticles, from the selection of the strain to the settings of reaction parameters. Mechanisms involved in the microbial production of NPs are also discussed, summarizing general findings and implications in the process. There is also a section dedicated to the identification of wastes as a source of precious metals and the production of metallic NPs from waste streams containing ionic metals to give a vision of the opportunities to implement microbial synthesis as a treatment–recovery technology. Environmental applications of biogenic NPs are reviewed in detail indicating that the implementation of these nanomaterials enable the achievement of higher removal efficiencies and greater extent of transformation of recalcitrant compounds in wastewater treatment systems. Under this scenario and based on the information reviewed concluding remarks and futures perspectives are enunciated. © 2018 Society of Chemical Industry."


Bioremediation Nanomaterials Microbial synthesis Recovery Wastewater treatment Nanoparticle Mechanisms CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Experimental studies on the mechanical behavior of Mayan archeological rocks

Estudios experimentales del comportamiento mecánico de rocas arqueológicas Mayas


Mayan buildings have been the subject of significant archaeological and architectural research; however, so far there have been no relevant references concerning structural or mechanical behavior. Ancient Mayan constructors used calcareous rocks to build temples and housing that were placed systematically to withstand mechanical loads in the structures. This paper studies the mineralogical and mechanical characteristics of calcareous stony material that formed part of Mayan archeological vestiges in Yucatan area. The orientation of the rocks´ geological strata was taken into account to study mechanical behavior from cylindrical cores in compressing test. On the other hand, bars were also manufactured to simulate lintel or architrave structural performance. Compression and bending tests confirmed a high influence of the geological layer orientation, since the mechanical properties of such rocks were found to vary with direction. Acoustic emission was used to provide information referring to onset and propagation of damage in cylinder and bar samples.



Determination of resistance in winter wheat genotypes to the dryland root rots caused by Fusarium Culmorum in Turkey

GUL ERGINBAS ORAKCI Alexey Morgounov Abdelfattah DABABAT (2018)

Kuru alan kök (kökboğazı/dip) çürüklükleri’ne neden olan fusarium türleri tahıllara özellikle buğdaya zarar vermekte, tane sayı ve kalitesini azaltarak önemli verim kaybına neden olmaktadır. Türkiye’de kök çürüklüğü hastalık etmeni fusarium türleri içinde buğday bitkisine zarar veren başlıca etmen olarak rapor edilen tür fusarium culmorum’dur. Maalesef, günümüze kadar fusarium türlerine karşı sadece birkaç kısmi dayanıklı buğday genotipi bulunmuştur. Bu nedenle, bu çalışma fusarium hastalığının neden olduğu zararı sınırlandırmak amacıyla çeşitli buğday genotiplerinde yeni dayanıklılık kaynaklarının bulunması amacıyla yürütülmüştür. Çalışmada, uluslararası kışlık buğday geliştirme programı (iwwip) aracılığıyla 19 farklı ülke’den toplam 141 ıslah materyali (hat ve çeşit) sağlanmıştır ve türkiye’de 3 farklı ortamda (büyütme odası,sera, tarla) yerel izolat fusarium culmorum’a karşı dayanıklılıklarının belirlenmesi amacıyla 2012 yılında test edilmiştir. Dayanıklılık bakımından en iyi performansı gösteren genotipler verilerin doğrulanması amacıyla 2013 yılında tekrar test edilmiştir. Fenotiplendirme yapılan 141 genotip içinden toplam materyalin %12’ lik kısmını oluşturan 17 genotip fide ve/veya yetişkin dönemde orta dayanıklı olarak gruplandırılmıştır. Meksika kaynaklı genotipler, fide dayanıklılığı daha fazla gösteren amerika kaynaklı genotiplerin aksine yetişkin dönem dayanıklılığı göstermiştir. Yüksek dayanıklılık gösteren kışlık buğdaylar patwin yr5 ve tast/sprw//zar/5/yuandong 3/4/ppb8-68/chrc/3/pyn//tam101/amigo kök çürüklüğü’ ne karşı ıslahta ümitvar olarak görülmektedir.



Modelling of the carrier transport properties in nanostructured devices with applications in advanced logic technologies

Hector Uribe-Vargas (2018)

Ultra-thin high-k oxides are widely used in todays advanced Complementary Metal-Oxide-Semiconductor technology to continue

scalability and to increase performance due to a large dielectric constant (k>8) and low leakage current. Understanding conduction mechanisms (CMs) through these oxides is important to accurately make predictions ensuring the long-term operation of these devices. Nevertheless, this task presents several challenges due to several physical and electronic considerations like: 1) precise atomic control of the high-k material in the ultra-thin regime (thickness, stoichiometry, dielectric constant, etc), 2) excessively large gate leakage current levels, 3) appearance of several conduction mechanisms which degrade the performance and reliability of the devices, 4) interfacial defects at the high-k/silicon interface and 5) low thermodynamic stability of the high-k materials. With the purpose to make accurate predictions of lifetime and/or reliability characteristics, this work reviews the conduction mechanisms of fabricated Metal-Insulator-Semiconductor (MIS) devices using ultra-thin Al₂O₃, HfO₂, and TiO₂, (less than 10 nm in thickness for each dielectric) deposited by Atomic Layer Deposition (ALD). This deposition technique presents several advantages like: 1) high reproducibility and conformality, 2) outstanding control (to atomic level) on the thickness and stoichiometry, 3) good interface properties with the semiconductor substrate, and 4) low deposition temperature (T ≤ 250°C) for these metal oxides which enables enhanced performance and therefore, more accurate reliability predictions. After fabrication, MIS devices were electrically characterized using standard Ig-Vg, C-V, and Ig-Vg-temperature measurement to determine the precise carrier conduction mechanism for each dielectric under different conditions of passivation (SiOx) and post-metallization annealing. Physical and electronic parameters such as barrier height 𝚽ᴃ, energy trap level 𝚽ᴛ and effective mass m* were extracted and further validated using semi-empirical models in MATLAB and SILVACO and compared with those found in literature, having excellent agreement. From this study a simple but practical correlation between materials’ properties with device performance could be obtained and compared among these high-k oxides.

Los dieléctricos ultra-delgados de alta constante son muy usados en la en la tecnología actual basada en el transistor de efecto de campo con el fin de continuar el escalamiento y mejorar el desempeño debido a que presentan una alta constante dieléctrica (k>8) y una baja corriente de fuga. Entender los mecanismos de conducción a través de estos óxidos es importante ya que podremos realizar predicciones precisas en cuanto al comportamiento a largo plazo de estos dispositivos. Sin embargo, esta tarea presenta varios retos debido a algunas consideraciones físicas y electrónicas como lo son 1) el control atómico preciso de estos óxidos en el régimen ultra-delgado (espesor, estequiometria, constante dieléctrica, etc.) 2) excesivas corrientes de fuga, 3) la aparición de diferentes mecanismos de conducción que degradan el dispositivo, 4) defectos en la interfaz entre el dieléctrico y el silicio y 5) baja estabilidad térmica.

Con el propósito de hacer predicciones precisas acerca del rendimiento y la confiabilidad de estos óxidos, en este trabajo hemos revisado y analizado los mecanismos de conducción de estructuras Metal-Aislante-Semiconductor (MIS) utilizando Al₂O₃, HfO₂ y TiO₂ como oxido de compuerta en el régimen ultra-delgado (>10 nm de espesor) depositados por Atomic Layer Deposition (ALD). Esta técnica de depósito presenta ventajas como lo son 1) alta reproducibilidad y depósito conformal, 2) excelente control en espesor y estequiometria, 3) excelentes propiedades en la interfaz oxido/semiconductor, y 4) baja temperatura de depósito (T ≤ 250°C), lo que permite un excelente desempeño y predicciones más precisas de confiabilidad.

Los dispositivos fabricados fueron caracterizados utilizando técnicas de medición estándar Ig-Vg, C-V e Ig-Vg-T para determinar los mecanismos de conducción asociados a cada uno de ellos bajo diferentes variaciones de proceso (pasivados y tratamiento térmico). De estas mediciones, parámetros físicos y electrónicos como lo son la altura de barrera 𝚽ᴃ, el nivel energético de trampas 𝚽ᴛ y la masa efectiva m* fueron obtenidos y validados usando simulaciones en MATLAB y SILVACO, para después comparar los valores obtenidos con literatura, donde hubo una gran concordancia. De este estudio, una relación entre propiedades de materiales y desempeño de dispositivos puede analizarse.

Doctoral thesis


Proteínas Involucradas en los Mecanismos de Defensa de Plantas


Las plantas careciendo de un sistema dedefensa basado en anticuerpos similar al que existe en animales, basan su protección en características físicas y en una serie de componentes que la propia planta sintetiza. Dentro de esos compuestos, las proteínas constituyen una de las principales fuentes de defensa, no sólo por su elevada especificidad y eficiencia, sino porque además algunas de ellas son altamente reguladas, respondiendo su síntesis al ataque de los depredadores (insectos) o de los patógenos. Estas proteínas representan una interesante alternativa para producir plantas con mejores características de resistencia, ya que a través de mecanismos de fitomejoramiento o bien introduciendo el gen a plantas sensibles, por medio de la ingeniería genética. El conocimiento de sus mecanismos de acción representa una forma importante para aprender a combatir plagas y enfermedades de las plantas, sin tener que utilizar compuestos altamente contaminantes, como son los insecticidas comerciales.

The plants lacking a defense system based on similar antibodies to which exists in animals, bases their protection on physical characteristics and in a series of components that the own plant synthesizes. Inside those compounds, the proteins constitute one of the main defense sources, not only for their high specificity and

efficiency, but because some of them are also highly regulated, their synthesis responding to the attack of the insects or by pathogens. These proteins represent an interesting alternative to produce plants

with better resistance characteristics, since through breeding mechanisms or introducing the gene a susceptible plant, by means of the genetic engineering. The knowledge of its action mechanisms

represents an important form to learn how to combat plagues and illnesses of the plants, without having to use compound highly polluting, like the commercial insecticides.


BIOLOGÍA Y QUÍMICA Mecanismos de defensa de plantas Proteínas de defensa Inhibidores de enzimas Defense mechanisms Defense proteins Enzyme inhibitors

Impact of the base doping concentration on the transport mechanisms in n-type a-SiGe:H/p-type c-Silicon Heterojunctions


The charge transport mechanisms occurring in n-type a-SiGe:H on p-type c-Si heterojunctions were determined by analyzing the temperature dependence of the current-voltage characteristics in structures with four different peak base doping concentrations (NB = 1x10^15, 7x10^16, 7x10^17 and 5x10^18 cm-3). From the experimental results, we observed that at low forward bias (V< 0.45V) the current is determined by electron diffusion from the n-type amorphous film to the p-type c-Si for the heterojunction with NB = 1x10^15cm-3, whereas the Multi- Tunneling Capture Emission (MTCE) was identified as the main transport mechanism for the other base doping concentrations. On the other hand, at high forward bias (V> 0.45V), the space charge limited current effect became the dominant transport mechanism for all the measured devices. Under reverse bias the transport mechanisms depends on the peak base doping, going from carrier generation inside the space charge region for the lowest doping, to hopping and thermionic field emission as the base doping concentration is increased.

Heterouniones de a-SiGe:H tipo-n sobre silicio cristalino tipo-p con cuatro diferentes concentraciones pico en la base (1x10^15, 7x10^16, 7x10^17 y 5x10^18 cm-3) fueron fabricadas y caracterizadas. Los mecanismos de transporte se determinaron por medio de sus curvas características de corriente vs voltaje en función de la temperatura. El análisis de los resultados muestra que a bajos voltajes de polarización directa (V< 0.45V) en la heterounión con la menor concentración pico la corriente es determinada por la difusión de electrones del a-SiGe:H tipo-n hacia el silicio cristalino tipo-p. Mientras que el multituneleo captura-emisión (MTCE) es el principal mecanismo de transporte en las otras heterouniones. A altos voltajes de polarización directa (V> 0.45V) el efecto de corriente limitada por carga espacial (SCLC) es el mecanismo de transporte dominante en todos los dispositivos caracterizados. El incremento en la concentración de dopantes en la base, además, causa un aumento en la corriente inversa.


Amorphous semiconductors Heterojunction diodes Transport mechanisms Base doping concentration Semiconductores amorfos Heterouniones Mecanismos de transporte Concentración de dopantes en la base CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA ELECTRÓNICA

Política ambiental: uso y manejo del estiércol en la Comarca Lagunera

Environmental policy: use and manure management in Comarca Lagunera


Teniendo en cuenta el creciente desarrollo que ha adquirido la contaminación ambiental, es necesario analizar las actividades en la cadena del estiércol, desde la recolección hasta la aplicación. El uso de estiércol como fertilizante es una de las prácticas más antiguas utilizadas en la agricultura; sin embargo, la aplicación continua incrementa el riesgo de contaminación. La aproximación es principalmente empírica y combina trabajo de campo con el análisis del marco regulatorio en México. Se encontró que una práctica común en la Comarca Lagunera es la aplicación en dosis de hasta 150 ton/ha, sin un tratamiento previo. Respecto a la regulación, el manejo del estiércol es muy puntual. No se han generado estímulos para dimensionar y disminuir el impacto ambiental que se deriva de las actividades pecuarias. Adoptar medidas establecidas en otros países es una buena opción, un tratamiento y manejo adecuado del estiércol que disminuyan los problemas ocasionados.

Considering the increasing environmental pollution, it is necessary to analyze the activities in the manure chain, from collection to the application. The use of manure as fertilizer is one of the oldest practices in agriculture; however, continuous application increases the risk of

contamination. The approach is mainly empirical, and combines fieldwork with the analysis of the regulatory framework in Mexico. A common practice in the Comarca Lagunera is the application at doses up to 150 ton/ha, without pretreatment. Regarding the regulation,

manure management is very punctual. Have not been generated incentives to dimension and reduce the environmental impact derived from livestock activities. Take measures established in other countries is a good choice, since proper treatment and manure management to decrease the problems caused.


Estiércol Manure CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA Contaminación Mecanismos de regulación Actividades pecuarias Pollution Regulatory mechanisms Livestock activities

Observational evidence for the link between the variable optical continuum and the subparsec-scale jet of the radio galaxy 3C 390.3


The mechanism and the region of generation of variable continuum emission are poorly understood for radio-loud AGN because of a complexity of the nuclear region. High-resolution radio VLBI (very long baseline interferometry) observations allow zooming into a subparsec-scale region of the jet in the radio-loud galaxy 3C390.3. We combined the radio VLBI and the optical data covering the time period of 14 years to look for a link between optical flares and parsec-scale jet. We identify two stationary and nine moving radio features in the innermost subparsec-scale region of the jet. All nine ejections are associated with optical flares. We found a significant correlation (at a confidence level of > 99.99%) between the ejected jet components and optical continuum flares. The epochs at which the moving knots pass through the location of a stationary radio feature and the optical light curve reaches the maximum are correlated. The radio events follow the maxima of optical flares with the mean time delay of 0.10 ± 0.04 years. This correlation can be understood if the variable optical continuum emission is generated in the innermost part of the jet. A possible mechanism of the energy release is the ejection of knots of high-energy electrons that are accelerated in the jet flow and generate flares of synchrotron continuum emission in the wide range of frequencies from radio to X-ray bands. In this scenario, the beamed optical continuum emission from the jet and counterjet ionizes a gas in a subrelativistic outflow surrounding the jet, which results in a formation of two outflowing conical regions with broad emission lines (in addition to the conventional broad line región around the central nucleus).


Galaxies: jets Galaxies: nuclei Galaxies: individual: 3C390.3 – Radiation mechanisms: non-thermal CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA ASTRONOMÍA Y ASTROFÍSICA

Modelo de emisión de rayos gamma de la galaxia de Andrómeda


A model of diffuse gamma-ray emission is presented. The diffuse

gamma-ray emission is directly related to the distribution of gas and radiation in

an object and to its star formation. The relationship with star formation is due

to supernovae behaving as cosmic-ray accelerators. To model this emission from

M31, I have used the HI map of Brinks & Shane (1984) to represent the atomic

gas content and the CO map of Nieten et al (2006) to represent the molecular

hydrogen content. To represent the radiation field, I have used maps of M31 in

different bands, from infrared to ultraviolet. These images have been normalized to

the spectral energy distribution of M31. The cosmic-ray spectrum is a power law

whose indices are p = 2.76 for electrons and k = 2.71 for protons; heavier nuclei

are not currently included. These two spectra have been normalized assuming

energy equipartition between cosmic-rays and the magnetic field and a protonto-

electron ratio of 100. In these calculations I used the values for the magnetic

field strength given by Beck (1981) of 3.2 ± 0.9μG in the ring and 2.4μG in the

disk. The gamma-ray mechanisms that are used in this model are neutral pion

decay, bremsstrahlung and inverse Compton scattering. Production functions that

express the number of gamma-rays produced per unit of time per unit of nucleon

energy were obtained from Berstch et al (1993) and Haung et al (2007). The

model uses maps of gas derived from HI and CO emission lines, and maps of the

radiation field, and production functions as inputs. This gives a map of emission

in gamma-rays of M31. The integrated flux above photon energies of 100MeV is

2.11 × 10−8 photon s−1cm−2. A maximum likelihood analysis was applied to the

model map and the all-sky maps observed by EGRET. With this analysis I found

an upper limit of 7.9×10−9photons cm−2s−1 to the gamma-ray flux above 100MeV

for M31, implying a modification of the input parameters to the model. The most

probable error in the input was adopting a magnetic field strength a factor of ∼ 2

too high. A field strength of ∼ 2μG is the most appropriate value on large scales

in M31. The results of this model have been compared with flux estimates of

M31 in the same energy range made by other authors. ¨Ozel & Berkhuijsen (1987)

estimated a flux of 2.4×10−8ξ photons cm−2s−1 with ξ < 5 and Pavlidou & Fields

(2001) calculated 1×10−8photons cm−2s−1 respectively.

Master thesis

Gamma-ray astronomy Astrophysical radiation mechanisms Gamma-rays CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA ASTRONOMÍA Y ASTROFÍSICA

Caracterización de los mecanismos antagónicos de Debaryomyces hansenii contra Colletotrichum gloeosporioides y su efecto en la protección poscosecha en papaya var. Maradol


"Se evaluó el efecto de control de Debaryomyces hansenii sobre Colletotrichum gloeosporioides a través de los mecanismos antagónicos de competencia por carbohidratos, producción de enzimas hidrolíticas, producción de compuestos orgánicos volátiles, adhesión al patógeno, formación de biopelículas y concentración del antagonista. Además, se analizó el efecto de control sobre C. gloeosporioides al inocular al antagonista en frutos de papaya var. Maradol en diferentes tiempos, y se realizó un ensayo bajo condiciones de comercialización local. Los resultados muestran que la concentración de 108 cel∙mL-1 de antagonista maximiza el efecto de los mecanismos antagónicos contra C. gloeosporioides. Con esta concentración se observa que la levadura es capaz de producir biopelículas sobre las heridas de frutos de papaya, evitando al 100% la infección de C. gloeosporioides. El ensayo de tiempos de inoculación del antagonista indicó que la levadura es capaz de controlar al fitopatógeno al 100%, antes y después de su establecimiento en el fruto de papaya. Bajo condiciones de comercialización local la levadura tiene un efecto de protección contra hongos en el 50% de los frutos, mientras que el fungicida comercial solo presenta un 30%. Además, la aplicación de levadura no tiene efecto en el desarrollo del color de los frutos. La levadura D. hansenii presenta todos los mecanismos antagónicos ensayados; sin embargo, la protección de los frutos de papaya contra la antracnosis está relacionada directamente con la competencia por espacio y carbohidratos, así como con la formación de biopelículas."

"The control effect of Debaryomyces hansenii on Colletotrichum gloeosporioides was evaluated through the antagonistic mechanisms of carbohydrate competition, production of hydrolytic enzymes, production of volatile organic compounds, adhesion on phytopathogen, biofilm formation and antagonist concentration. In addition, the control effect on C. gloeosporioides was tested when inoculating the antagonist on Maradol papaya fruits at different times, and an assay was performed under local marketing conditions. The results show that the antagonist concentration at 108 cel∙mL-1 maximizes the effect of antagonistic mechanisms against C. gloeosporioides. With that concentration, it is observed that the yeast is capable of producing biofilms on the wounds of papaya fruits, avoiding the infection of C. gloeosporioides at 100%. The test of inoculation times of the antagonist indicated that the yeast can control the phytopathogen at 100%, before and after its establishment in the papaya fruits. Under local commercialization conditions yeast has a protective effect against fungi in 50% of the fruits, while the commercial fungicide only presents 30%. In addition, the application of yeast has no effect on the development of fruit color. The yeast D. hansenii presents all the antagonistic mechanisms tested; however, the protection of papaya fruits against anthracnose is directly related to competition for space and carbohydrates, as well as the formation of biofilms."

Master thesis

Colletotrichum gloeosporioides, Debaryomyces hansenii, Mecanismos antagónicos, Biopelículas Antagonistic mechanisms , Biofilms CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS FITOPATOLOGÍA CONTROL BIOLÓGICO DE ENFERMEDADES