1,910 research outputs found
Cultivo de colza para produção de biodiesel
Cultivo de colza para produção de biodieselO presente trabalho teve como objetivo principal estudar a adaptação da colza às
condições de cultivo do Nordeste de Portugal. Procedeu-se ainda à determinação laboratorial
do teor de óleo em sementes de colza. A partir de óleos alimentares usados foi
produzido biodiesel e determinados os índices de iodo e de acidez, de acordo com as
normas EN14111 e EN14104, respetivamente.
Aspetos pouco conhecidos sobre a mecanização de operações culturais como a sementeira
e colheita foram estudados, tendo-se encontrado algumas respostas para as
características que o semeador a eleger deve conter e regulações a efetuar na ceifeira-
-debulhadora a usar na colheita.
A produção de colza em campo foi bastante penalizada pelas condições de seca
severa que se registaram no Inverno e início da Primavera desse mesmo ano, não tendo
sido possível observar efeitos significativos entre as diferentes modalidades experimentais.
A produção média de colza em cada um dos talhões foi da ordem de 1000 kg
semente ha-1. O teor em óleo das sementes de colza variou entre 41.7 e 42.0%. Relativamente
ao índice de acidez do biocombustível obteve-se 0.16 g KOH/g amostra e quanto
ao índice de iodo registou-se o valor de 130.32 g iodo/100 g de biocombustível
Into the depths of deep eutectic solvents
Ionic liquids (ILs) have been successfully tested in a wide range of applications; however, their high price and complicated synthesis make them infeasible for large scale implementation. A decade ago, a new generation of solvents so called deep eutectic solvents (DESs) was reported for the first time. DESs show similar properties to ILs and they have proven to be an excellent alternative to ILs in many applications where ILs succeeded first. Besides, DESs can be prepared easily and cheaply, with low-cost starting materials, no need of solvents, no atom loss during the formation and no additional purification requirements. The main problem that scientist are facing when they want to use DESs in different applications is the lack of information on the fundamentals of these solvents. Why do they form? How do they form? How do the hydrogen bond donor (HBD) and the hydrogen bond acceptor (HBA) interact? How do DESs interact with other compounds? Can we predict their thermophysical properties? The answer to these questions will provide to researches new insights on the application of these solvents, solving the problem of trial-and-error experimentation. In this work, we present a detailed analysis of molecular interactions and conformational states of two selected DESs: lactic acid – choline chloride (2:1) and glycolic acid – choline chloride (1:1), using density functional theory (DFT) and second-order Møller¿Plesset perturbation theory (MP2) with various basis sets. Theoretical calculations were performed using the GAUSSIAN 03 software package. The obtained results are used to evaluate the nature of interactions between the HBD and HBA and their structural features. Additionally, it will contribute to the better understanding of how DESs are formed
Utilization of Pachysolen tannophilus and Pichia kudriavzevii for the production of xylitol on undetoxified corn cob hydrolysates
Received: February 19th, 2022 ; Accepted: April 24th, 2022 ; Published: April 29th, 2022 ; Correspondence: [email protected] is a natural polyol with broad applications in the food and pharmaceutical
industries. However, its large-scale production through chemical means is still an expensive and
not environmentally friendly process. Therefore, great attention has been paid to low-cost and
renewable substrates like corn cobs (CC), which can be utilized to improve the economic outlook
of xylitol production. In this study, CC were used as a feedstock for xylitol production, with the
help of yeasts and filamentous fungi. The results obtained in this study showed that the amount
of xylitol produced from CC hydrolysate was similar to the amount of xylitol obtained on xylose
substrate. Overall, yeast produced higher amounts of xylitol than filamentous fungi. Pachysolen
tannophilus had the highest xylitol production at pH 5.0, 72 h fermentation time, substrate
concentration 15%, and inoculum size 1.5×108
cfu mL-1
, while Pichia kudriavzevii performed
better at pH 5.0, with a 72 h fermentation time, substrate concentration of 20%, and inoculum
size of 2.5×108
cfu mL-1
. When comparing the combined optimal parameters with and without
supplementation, supplementation with 1.5% methanol, has increased the xylitol production of
P. tannophilus and P. kudriavzevii by 31% and 18.6%, respectively. These findings demonstrate
the robustness of these yeast strains for sustainable and cost-effective xylitol production from CC
waste
Phosphate solubilization potential of indigenous rhizosphere fungi and their biofertilizer formulations
Received: September 28th, 2021 ; Accepted: December 13th, 2021 ; Published: December 16th, 2021 ; Correspondence: [email protected] harmful effects of chemical fertilizers on soil, plants, and eco-systems have
stimulated the growth of the global biofertilizer market. However, biofertilizer use remains
limited in developing countries due to inadequate research and poor technology. The use of
readily available materials for biofertilizer production can be a good starting point. This study
aimed to investigate phosphate-solubilizing potentials of soil fungi and the shelf-life of their
biofertilizer formulations using sawdust and charcoal as carriers. Soil samples from the
rhizosphere were cultured on Pikovskaya (PVK) agar, and the best phosphate solubilizers
(Aspergillus niger, Aspergillus fumigatus and A. flavus) were screened for their phosphatesolubilization potentials on solid medium. Results obtained showed that A. niger had the highest
solubilization index of 1.72, followed by A. fumigatus, and A. flavus with a solubilization index
of 1.01 and 0.95, respectively. Optimization studies showed that after 5 days of incubation,
A. niger, A. flavus and A. fumigatus solubilized 149, 112 and 126 mg L-1 of phosphate,
respectively. These values increased to 549 mg L-1 on day 11 for A. niger, 379 mg L-1 on day 9
for A. flavus and 430 mg L-1 on day 9 for A. fumigatus. Furthermore, A. fumigatus and A. flavus
proved to be better inoculants than A. niger as they maintained higher CFU g-1 counts throughout
the experiment. Also, sawdust supported higher counts of the three inoculants than charcoal and
was thus the best carrier. The findings demonstrated that these aspergilli can be harnessed for
improving soil fertility and plant development
2,6-Diphenylpyridine
In the title compound, C17H13N, the dihedral angles between the pyridine ring and the phenyl rings are 29.68 (18) and 26.58 (17)°. In the crystal structure, the molecules are linked by a weak C-H interaction, leading to [01] chains. There are no further significant intermolecular interactions
Do the low molecular weight heparins improve efficacy and safety of the treatment of deep venous thrombosis? A meta-analysis
We compared the efficacy and safety of low molecular
weight heparins (LMWH) and unfractionated heparin (UFH) in the treatement of deep
venous thrombosis (DVT). A comparison between two daily subcutaneous injections
of LMWH against a single injection was also performed. DESIGN AND METHODS: The
study was performed by a meta-analysis. Clot improvement in venography,
recurrency, total mortality and major hemorrhages were assessed in 4,472 patients
with DVT from 21 studies treated with subcutaneous LMWH or UFH. RESULTS: An
improvement in clot reduction (odds ratio 0.73, 95% confidence interval 0.59 to
0.90, p = 0.004), a decrease in total mortality (0. 68, 0.50 to 0.91, p = 0.012)
and a lower incidence of hemorrhage (0. 65, 0.43 to 0.98, p = 0.047) were
observed in LMWH treated patients. There were no differences in recurrences
(0.78, 0.59 to 1.04, p = 0. 10). A single dose of LMWH was better than two in
reducing major bleeding (c2 = 4.99, p = 0.025); however, the two dose regimen was
more effective in clot reduction (c2 = 8.56, p = 0.004). INTERPRETATION AND
CONCLUSIONS: LMWH is superior to UFH in terms of safety and efficacy. A single
daily dose of LMWH dose is a suitable therapeutic regimen and could facilitate
the outpatient treatment of venous thromboembolism
Desempenho de um semeador adaptado para sementes pequenas
A sementeira mecânica de sementes pequenas (2.5 g – 7.6 g / 1000 grãos) nem sempre é executada com eficiência, quer pela reduzida quantidade de semente a aplicar por unidade de área (100 a 200 grãos por m2), quer pela reduzida profundidade de sementeira, até 1 a 2 cm.
Com o objetivo de avaliar o desempenho do semeador Sola Trisem 194 neste tipo de sementeira foram realizados ensaios de campo com Brassica Napus L., sendo medidos por cronometragem os tempos elementares de trabalho e calculadas a capacidade de trabalho e eficiência de campo.info:eu-repo/semantics/publishedVersio
El gusano tornillo: una amenaza para las plataneras.
El gusano tornillo (Castniomera humbolti) constituye una plaga de importancia económica en zonas plataneras de varios departamentos del país. Se describen las características morfológicas y duración de los distintos estados de este Lepidoptero, el tipo de daño que ocasiona, las plantas hospederas y las prácticas recomendadas para su contro
- …