Long-range versus short-range correlations in the two-neutron transfer reaction Ni 64 (O 18, O 16) Ni 66

Recently, various two-neutron transfer studies using the (O18,O16) reaction were performed with a large success. This was achieved because of a combined use of the microscopic quantum description of the reaction mechanism and of the nuclear structure. In the present work we use this methodology to study the two-neutron transfer reaction of the O18+Ni64 system at 84 MeV incident energy, to the ground and first 2+ excited state of the residual Ni66 nucleus. All the experimental data were measured by the large acceptance MAGNEX spectrometer at the Instituto Nazionale di Fisica Nucleare -Laboratori Nazionali del Sud (Italy). We have performed exact finite range cross section calculations using the coupled channel Born approximation (CCBA) and coupled reaction channel (CRC) method for the sequential and direct two-neutron transfers, respectively. Moreover, this is the first time that the formalism of the microscopic interaction boson model (IBM-2) was applied to a two-neutron transfer reaction. From our results we conclude that for two-neutron transfer to the ground state of Ni66, the direct transfer is the dominant reaction mechanism, whereas for the transfer to the first excited state of Ni66, the sequential process dominates. A competition between long-range and short-range correlations is discussed, in particular, how the use of two different models (Shell model and IBM's) help to disentangle long- and short-range correlations

Respostas moleculares e fisiológicas de Pichia pastoris a componentes de hidrolisado lignocelulósico.

Resumo: Komagataella phaffii, anteriormente conhecida como Pichia pastoris, é um organismo modelo comummente usado na pesquisa e na indústria. Tem sido considerada para a produção de produtos de alto valor agregado, especialmente proteínas. Suas aplicações biotecnológicas envolvem principalmente a utilização de fontes clássicas de carbono como glicose, glicerol, sorbitol e metanol, embora muitos outros substratos também tenham sido pesquisados. As biomassas lignocelulósicas são ricas em açúcares fermentáveis, como a xilose, o segundo açúcar mais abundante na natureza, que pode ser usado para a produção de produtos químicos renováveis. No entanto, a utilização microbiana da xilose depende da capacidade inata de utilização desta pelo microrganismo, e de sua tolerância aos compostos inibidores presentes nos hidrolisados lignocelulósicos. Atualmente, entende-se que P. pastoris não é capaz de utilizar xilose como fonte de carbono a menos que seja modificada para isso, e sua sensibilidade a tais inibidores é pouco compreendida. Neste estudo, apresentamos as respostas moleculares e fisiológicas de P. pastoris aos principais componentes do hidrolisado lignocelulósico: inibidores derivados da lignocelulose, e a xilose. A análise fisiológica e transcricional de P. pastoris X33 para ácido acético, furaldeídos e hidrolisado de bagaço de cana-de-açúcar mostrou que eles afetam o metabolismo celular de forma dose-dependente, e se correlacionam positivamente com a quantidade de genes diferencialmente expressos. Ao contrário de outras leveduras industriais como Saccharomyces cerevisiae, P. pastoris pode consumir concomitantemente ácido acético com glicose como fonte de carbono, possivelmente ajudando a reduzir sua toxicidade para as células. A tolerância ao inibidor, e a capacidade de utilização da xilose de 25 isolados diferentes naturais e um de laboratório de Komagataella, de seis espécies diferentes, também foram avaliadas. Nenhum isolado com tolerância aos inibidores distintamente maior foi identificado, entretanto linhagens capazes de crescer em xilose foram. Três linhagens de melhor crescimento foram selecionadas e submetidas à engenharia adaptativa de laboratório (ALE) para otimização do consumo de xilose. A caracterização detalhada da assimilação da xilose pela via de oxirredução foi confirmada por ensaios utilizando marcação com isótopos de carbono 13C, apesar de precisar de mais de dez dias para duplicar. Por fim, uma estratégia de engenharia genética foi empregada para melhorar a tolerância de P. pastoris X33 ao ácido acético. Para isso, o gene homólogo HAA1, previamente descrito em S. cerevisiae como fator de transcrição envolvido na resposta ao estresse com ácido acético, foi identificado e superexpresso em P. pastoris X33. Isso melhorou o crescimento da levedura na presença de 2g.L-1 4,9 vezes após 24 h de cultivo. Juntos, os resultados apresentados aqui abrem caminho para a compreensão do metabolismo de P. pastoris na presença de hidrolisados lignocelulósicos, ácido acético, furaldeídos e xilose. Abstract: Komagataella phaffii, previously known as Pichia pastoris, is a common model organism used in research and industry. It has been considered for the production of high value-added products, especially proteins. Its biotechnological applications mostly involve the utilization of classical carbon sources like glucose, glycerol, sorbitol, and methanol, although many other substrates have also been researched. Lignocellulosic biomasses are rich in fermentable sugars, like xylose, the second most abundant sugar in nature, which can be used for the production of renewable chemicals. The microbial utilization of xylose is dependent on the innate utilization capacity by the microorganism, and its tolerance to inhibitory compounds present in lignocellulosic hydrolysates. The current understanding is that P. pastoris is not capable of utilizing xylose as a carbon source unless engineered towards it, and its sensitivity to such inhibitors is poorly understood. In this study, we present the molecular and physiological responses of P. pastoris to the major lignocellulosic hydrolysate components: lignocellulose-derived inhibitors, and xylose. The physiological and transcriptional analysis of P. pastoris X33 to acetic acid, furaldehydes, and sugarcane bagasse hydrolysate showed they affect cell metabolism in a dose-dependent way, and it positively correlates with the amount of differentially expressed genes. Unlike other industrial yeasts like Saccharomyces cerevisiae, P. pastoris can co-consume acetic acid with glucose as carbon source, possibly helping it reduce its toxicity to the cells. The inhibitor tolerance and xylose utilization capacity of 25 different natural and one laboratory Komagataella isolates of six different species was also evaluated. No isolates with higher tolerance towards inhibitors were identified, however, strains capable of growing on xylose were. The three best growing strains were selected and underwent adaptative laboratory evolution (ALE) for xylose consumption optimization. Detailed characterization of xylose assimilation via the oxidoreductase pathway was confirmed using carbon isotope 13C labeling, despite it needing more than ten days to duplicate. Finally, a genetic engineering strategy was employed to improve P. pastoris X33 tolerance towards acetic acid. For this, the homologous HAA1 gene previously described in S. cerevisiae as a transcriptional factor involved in acetic acid stress response was identified and overexpressed in P. pastoris X33. These improved yeast?s growth in the presence of 2g.L-1 4.9-fold after 24 h of cultivation. Altogether the results presented here paves the way to understanding P. pastoris metabolism in presence of lignocellulosic hydrolysates, acetic acid, furaldehydes, and xylose.Título em inglês: Molecular and physiological responses of Pichia pastoris to lignocellulosic hydrolysate components. Tese (Doutorado em Biologia Molecular) - Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Biologia Celular, Programa de Pós-Graduação em Biologia Molecular, Brasília, 2021. Orientadora: Prof. Dra. Ildinete Silva Pereira, coorientador: Prof. Dr. João Ricardo Moreira de Almeida (pesquisador da Embrapa Agroenergia), coorientador do estágio sanduíche: Prof. Dr. Diethard Mattanovich

An inexpensive direct reading tensiometer

Foi desenvolvido e testado um tensiômetro simples de leitura direta no tubo transparente e estabelecidas as relações entre a altura da câmara visível e a correspondente tensão, lida em manômetros. As regressões obedecem à lei dos gases perfeitos de Boyle-Mariotte e podem ser expressas por equações hiperbólicas, cujas constantes variam com a altura inicial da câmara. A melhor regressão é obtida quando se inicia a operação com uma câmara de ar entre 0,5 e 1,0 cm de altura. Nesse caso, a curva de regressão obtida pode ser expressa pela equação y = 800x/ (x + 1,8), onde y = tensão em mb e x = altura da câmara em cm. O tensiômetro de leitura direta, dispensando manômetros, torna-se um instrumento simples, barato e bastante confiável.A transparent tube tensiometer was developed and tested to establish the relationship between the visible chamber height and the tension read in the manometers. The regressions follow the law of perfect gas (Boyle & Mariotte) and may be expressed by hiperbolic equations. The constants of the equations varies with the initial chamber height. The best values of initial chamber height were between 0.5 to 1.0 cm, corresponding to the equation: y = 800x/ (x + 1.8), where y is the tension (mb) and x the chamber height (cm). The direct reading tensiometer described here makes unnecessary the manometers so making the tensiometer inexpresive and more reliable

STUDY OF THE O-18+Ni-64 TWO-NEUTRON TRANSFER REACTION AT 84 MeV BY MAGNEX

A study of the two-neutron transfer reaction of the O-18 + Ni-64 system at 84 MeV incident energy to the ground and first 2(+) excited state of the residual Ni-66 nucleus is presented. The experiment was performed at the INFN-LNS (Italy) by using the large acceptance MAGNEX spectrometer. Theoretical models are used in order to disentangle the competition between long-range and short-range correlations

Biogas production from dairy cattle manure, under organic and conventional production systems.

The purpose of this study was to evaluate the production of biogas, as well as the biogas production potential resulting from the anaerobic biodigestion of dairy cattle manure under organic (CMOS) and conventional (CMCS) production system. Also, the concentration of thermotolerant coliforms was evaluated after the biodigestion process. Therefore, bench biodigesters prototypes were supplied with CMOS and CMCS for 30 weeks. The experimental design was completely randomized with four repetitions for each treatment. Analysis of total solids (TS), volatile solids (VS), biogas production potential, most probable number (MPN) of thermotolerant coliforms were made. The cumulative biogas production was 6.18 L and 11.15 L, when using the CMOS and CMCS, respectively. Average biogas production potential of CMCS were 0.2; 2.6 and 2.9 L kg-1 substrate, ST and SV added, respectively and for CMOS 0.1; 1.4 and 1.9 L kg-1substrate, ST and SV added, respectively. After the anaerobic biodigestion process of CMOS and CMCS, it was observed that the concentrations of thermotolerant coliforms were well below than the limit established by law