ADICI 3N DE ROCA FOSF 3RICA Y CAMBIOS EN LAS FRACCIONES DE P EN SUELOS CON DIFERENTE HUMEDAD Y PER\uedODOS DE INCUBACI 3N

El objetivo de este trabajo fue comparar la disoluci\uf3n de la roca fosf\uf3rica (RF) Monte Fresco en dos suelos \ue1cidos muy contrastantes en caracter\uedsticas f\uedsico-qu\uedmicas, mediante un esquema de fraccionamiento a diferentes per\uedodos de incubaci\uf3n y contenidos de humedad. El suelo Iguana es muy arenoso, de baja fertilidad natural y baja capacidad de retenci\uf3n de fosfatos, mientras que el suelo Bram\uf3n es mucho m\ue1s \ue1cido y mayor contenido de Al cambiable pero con mayor fertilidad natural y alta capacidad de retenci\uf3n de fosfatos. En el suelo Iguana la RF se disolvi\uf3 en una mayor proporci\uf3n que en el suelo Bram\uf3n, ya que este suelo, a pesar de su fuerte acidez present\uf3 altos niveles de P (total y disponible) y Ca intercambiable los cuales generaron condiciones menos apropiadas para la reacci\uf3n de la RF. A lo largo de la incubaci\uf3n con RF, como resultado de la redistribuci\uf3n de las fracciones mayores de P (P-HCl y P-residual) originalmente presentes en la RF, ocurri\uf3 un incremento significativo para la fracciones P-resina y P-microbiano en el suelo Iguana, y de P-resina, P-microbiano, NaOH-Pi y Po en el suelo Bram\uf3n, en este caso, posiblemente asociado con sus mayores niveles de C. Un mayor contenido de humedad disminuy\uf3 los valores de las fracciones m\ue1s l\ue1biles (resina y NaHCO3) en ambos suelos, lo que implica, una mayor adsorci\uf3n del P al establecerse un mayor contacto entre las superficies adsorbentes y el f\uf3sforo reci\ue9n liberado de la roca fosf\uf3rica. Palabras clave adicionales: Adsorci\uf3n de P, biomasa microbiana, fraccionamiento de P, suelos \ue1cidos. ABSTRACT The objective of this study was to compare the dissolution of the phosphate rock (PR) Monte Fresco in two acidic soils very contrasting in physicochemical characteristics, through a scheme of fractionation at different periods of incubation and moisture contents. Iguana, a very sandy soil with a low natural fertility and low phosphate retention; and much more acid Bram\uf3n soil with a higher exchangeable Al content but with greater natural fertility and high capacity of phosphate retention. Iguana soil dissolved the PR in a greater proportion than the soil Bram\uf3n, since this soil, despite its strong acidity presented high levels of P (total and available) and exchangeable Ca which generated less appropriate conditions for the reaction of the PR. During incubation with PR, as a result of the redistribution of the major fractions of P (P-HCl and P-residual) originally present in the PR, occurred a significant increase for the P-resin and microbial-P fractions in Iguana soil; and in P-resin, microbial-P, NaOH-Pi and Po for Bram\uf3n soil, in this case, possibly associated with its higher C content. Higher moisture contents decreased more labile P-fractions (resin and NaHCO3) values in both soils, which implies, a higher adsorption of P due to a greater contact between the adsorbent surfaces and newly released P from the PR. Additional key words: Acid soils, microbial biomass, P-adsorption, P-fractionation. <br

Expression, purification and thermal stability evaluation of an engineered amaranth protein expressed in Escherichia coli

Background: The acidic subunit of amarantin (AAC)\u2014the predominant amaranth seed storage protein\u2014has functional potential and its third variable region (VR) has been modified with antihypertensive peptides to improve this potential. Here, we modified the C-terminal in the fourth VR of AAC by inserting four VY antihypertensive peptides. This modified protein (AACM.4) was expressed in Escherichia coli. In addition, we also recombinantly expressed other derivatives of the amarantin protein. These include: unmodified amarantin acidic subunit (AAC); amarantin acidic subunit modified at the third VR with four VY peptides (AACM.3); and amarantin acidic subunit doubly modified, in the third VR with four VY peptides and in the fourth VR with the RIPP peptide (AACM.3.4). Results: E. coli BL21-CodonPlus (DE3)-RIL was the most favorable strain for the expression of proteins. After 6 h of induction, it showed the best recombinant protein titer. The AAC and AACM.4 were obtained at higher titers (0.56 g/L) while proteins modified in the third VR showed lower titers: 0.44 g/L and 0.33 g/L for AACM.3 and AACM.3.4, respectively. As these AAC variants were mostly expressed in an insoluble form, we applied a refolding protocol. This made it possible to obtain all proteins in soluble form. Modification of the VR 4 improves the thermal stability of amarantin acidic subunit; AAC manifested melting temperature (Tm) at 34\ub0C and AACM.4 at 37.2\ub0C. The AACM.3 and AACM.3.4 did not show transition curves. Conclusions: Modifications to the third VR affect the thermal stability of amarantin acidic subunit

Fast evaluation of the adsorption energy of organic molecules on metals via graph neural networks

Modeling in heterogeneous catalysis requires the extensive evaluation of the energy of molecules adsorbed on surfaces. This is done via density functional theory but for large organic molecules it requires enormous computational time, compromising the viability of the approach. Here we present GAME-Net, a graph neural network to quickly evaluate the adsorption energy. GAME-Net is trained on a well-balanced chemically diverse dataset with C1–4 molecules with functional groups including N, O, S and C6–10 aromatic rings. The model yields a mean absolute error of 0.18 eV on the test set and is 6 orders of magnitude faster than density functional theory. Applied to biomass and plastics (up to 30 heteroatoms), adsorption energies are predicted with a mean absolute error of 0.016 eV per atom. The framework represents a tool for the fast screening of catalytic materials, particularly for systems that cannot be simulated by traditional methods

Schwartz - Zippelov teorem i neke njegove primjene

U ovom radu izložen je rezultat poznat pod nazivom Schwartz - Zippelova lema ili Schwartz - Zippelov teorem. Tema rada pripada pretežno algebri, ali ima značajne primjene u drugim matematičkim područjima kao što je na primjer teorija algoritama, te kombinatorika. Rad se sastoji od tri poglavlja. U uvodu je ukratko opisana tema i cilj rada. Prvo poglavlje sadrži kratku povijest nastanka teorema, različite oblike rezultata pojedinih autora, te kratki opis pojmova korištenih u samom radu. Drugo poglavlje sastoji se od iskaza i dokaza Schwartz - Zippelovog teorema, a u trećem poglavlju izložene su neke primjene tog teorema na probleme koji se mogu svesti na testiranje jednakosti polinoma. Takvi su, primjerice, problem postojanja savršenog sparivanja u grafu i ispitivanje svojstva asocijativnosti u grupoidu. Uz svaku primjenu navedeni su i prikladni primjeri.In this diploma thesis we present the result usually called the Schwartz-Zippel lemma or the Schwartz-Zippel theorem. The nature of this theorem is basically algebraic, but it has significant applications in other areas of mathematics, such as the theory of algorithms and combinatorial theory. The thesis consists of three chapters. The main theme and objective are briefly described in the introduction. The first chapter contains a short history of the theorem’s origins, various forms of the main results by different authors and some comments of basic concepts related to this topic. The statement and a proof of the Schwartz-Zippel theorem are given in the second chapter, together with the general outline of its applications. The third and final chapter consists of some applications to problems which can be reduced to polynomial identity testing, including the existence of a perfect matching in a graph and testing of the associativity property in a groupoi

Scaling-up batch conditions for efficient sucrose hydrolysis catalyzed by an immobilized recombinant Pichia pastoris cells in a stirrer tank reactor

Background: Invert sugar is used greatly in food and pharmaceutical industries. This paper describes scaling-up batch conditions for sucrose inversion catalyzed by the recombinant Pichia pastoris BfrA4X whole cells expressing Thermotoga maritima invertase entrapped in calcium alginate beads. For the first time, we describe the application of a kinetic model to predict the fractional conversion expected during sucrose hydrolysis reaction in both, a model and a prototype bioreactor with 0.5- and 5-L working volume, respectively. Results: Different scaled-up criteria used to operate the 0.5-L bioreactor were analyzed to explore the invert sugar large scale production. After model inversion studies, a 5-L scaled-up reaction system was performed in a 7-L stirred reactor. Both scaled-up criteria, immobilized biocatalyst dosage and stirring speed, were analyzed in each type of bioreactors and the collected data were used to ensure an efficient scale-up of this biocatalyst. Conclusions: To date, there is not enough information to describe the large-scale production of invert sugar using different scaled-up criteria such as dose of immobilized biocatalyst and stirring speed effect on mass transfer. The present study results constitute a valuable tool to successfully carry out this type of high-scale operation for industrial purposes

Optimization of worm-bed leachate for culturing of tomato ( Lycopersicon esculentum Mill) inoculated with Glomus fasciculatum and Pseudomonas fluorescens

A response surface technique was used to analyze the effect of Glomus fasciculatum , Pseudomonas fluorescens and worm-bed leachate (WBL) on growth, yield and characteristics of tomato ( Lycopersicon esculentum Mill). The treatments combined inoculation with or without P. fluorescens or G. fasciculatum and the application of WBL at 20% (v/v) each day or every three days. Plant height, number of leaves and yield of tomato fruits was not affected by the factors studied. However, plants with foliar application of WBL each day developed wider stems than those with an application every three days. The pH of the fruits was lower when WBL was applied every three days compared to a daily application. The soluble solids content of the fruits was higher when WBL was applied daily compared to those sprayed every three days. Plant development was not affected by addition of P. fluorescens, G. fasciculatum or WBL, but WBL changed fruit characteristics

Catalytical properties of N-glycosylated Gluconacetobacter diazotrophicus levansucrase produced in yeast

The influence of N-glycosylation on the kinetic and catalytical properties of a bacterial fructosyltransferase (LsdA) produced in Pichia pastoris was studied. The glycosylated enzyme behaved similarly to non-glycosylated LsdA when substrate specificity, fructo-oligosaccharide (FOS) production, sucrose hydrolysis or levan formation reactions were carried out under different experimental conditions. The kinetic parameters for native or yeast-expressed LsdA determined at 60\ub0C, condition for the highest hydrolytic activity, followed a conventional Michaelis-Menten kinetics. Synthase activity of this levansucrase increased in water-restricted environments by addition of salt or organic solvent to the reaction mixtures

VALES VI: ISM enrichment in star-forming galaxies up to z∼\sim0.2 using 12^{12}CO(1-0), 13^{13}CO(1-0) and C18^{18}O(1-0) line luminosity ratios

We present Atacama Large Millimeter/sub-millimeter Array (ALMA) observations towards 27 low-redshift ($0.02< z<0.2$) star-forming galaxies taken from the Valpara\'iso ALMA/APEX Line Emission Survey (VALES). We perform stacking analyses of the $^{12}$CO($1-0$), $^{13}$CO($1-0$) and C$^{18}$O($1-0$) emission lines to explore the $L'$ ($^{12}$CO($1-0$))/$L'$($^{13}$CO($1-0$))) (hereafter $L'$($^{12}$CO)/$L'$($^{13}$CO)) and $L'$($^{13}$CO($1-0$))/$L'$(C$^{18}$O($1-0$)) (hereafter $L'$($^{13}$CO)/$L'$(C$^{18}$O) line luminosity ratio dependence as a function of different global galaxy parameters related to the star formation activity. The sample has far-IR luminosities $10^{10.1-11.9}$L$_{\odot}$ and stellar masses of $10^{9.8-10.9}$M$_{\odot}$ corresponding to typical star-forming and starburst galaxies at these redshifts. On average we find a $L'$($^{12}$CO)/$L'$($^{13}$CO) line luminosity ratio value of 16.1$\pm$2.5. Galaxies with evidences of possible merging activity tend to show higher $L'$($^{12}$CO)/$L'$($^{13}$CO) ratios by a factor of two, while variations of this order are also found in galaxy samples with higher star formation rates or star formation efficiencies. We also find an average $L'$($^{13}$CO)/$L'$(C$^{18}$O) line luminosity ratio of 2.5$\pm$0.6, which is in good agreement with those previously reported for starburst galaxies. We find that galaxy samples with high $L_{\text{IR}}$, SFR and SFE show low $L'$($^{13}$CO)/$L'$(C$^{18}$O) line luminosity ratios with high $L'$($^{12}$CO)/$L'$($^{13}$CO) line luminosity ratios, suggesting that these trends are produced by selective enrichment of massive stars in young starbursts.Comment: 16 pages, 10 figures to be published in MNRA

Synthesis of Densely Packaged, Ultrasmall Pt02Clusters within a Thioether-Functionalized MOF: Catalytic Activity in Industrial Reactions at Low Temperature

The gram\u2010scale synthesis, stabilization, and characterization of well\u2010defined ultrasmall subnanometric catalytic clusters on solids is a challenge. The chemical synthesis and X\u2010ray snapshots of Pt02 clusters, homogenously distributed and densely packaged within the channels of a metal\u2013organic framework, is presented. This hybrid material catalyzes efficiently, and even more importantly from an economic and environmental viewpoint, at low temperature (25 to 140\u2009\ub0C), energetically costly industrial reactions in the gas phase such as HCN production, CO2 methanation, and alkene hydrogenations. These results open the way for the design of precisely defined catalytically active ultrasmall metal clusters in solids for technically easier, cheaper, and dramatically less\u2010dangerous industrial reactions

Are there changes in the nutritional status of children of Oportunidades families in rural Chiapas, Mexico? A cohort prospective study

Background: In Mexico, despite that the fact that several social programs have been implemented, chronic undernutrition is still a public health problem affecting 1.5 million children of &lt;5 years. Chiapas ranks first in underweight and stunting at national level with a stunting prevalence of 31.4 % whereas for its rural population is 44.2 %. The purpose of this paper is to determine if the nutritional status of a cohort of children living in poor rural communities under Oportunidades has changed. We were interested in assessing the nutrition evolution of the children who were initially diagnosed as stunted and of those who were diagnosed as normal. Oportunidades is an anti-poverty program of the Mexican government consisting mainly in monetary transfers to the families living in alimentary poverty. Methods: A 9-year cohort prospective study was conducted with nutritional evaluations of 222 children. Anthropometric indices were constructed from measurements of weight, height, and age of the children whose nutritional status was classified following WHO standards. Results: The results showed that although these children were Oportunidades beneficiaries for 9 years and their families improved their living conditions, children still had a high prevalence of stunting (40.1 %) and 69.6 % had not recovered yet. Children who were initially diagnosed with normal nutritional status and became stunted 2 years later had a higher risk (relative risk (RR) 5.69, 2.95\u201310.96) of continuing stunted at school age and adolescence. Conclusions: Oportunidades has not impacted, as expected, the nutritional status of the study population. These findings pose the question: Why has not the nutritional status of children improved, although the living conditions of their families have significantly improved? This might be the result of an adaptation process achieved through a decrease of growth velocity. It is important to make efforts to watch the growth of the children during their first 3 years of age, to focus on improving the diet of women at fertile age and pay special attention to environmental conditions to break the vicious cycle of malnutrition