The present work reveals the potential applicability of banana leaf waste as feedstock for bioethanol production as very less work has been reported on this feedstock. For achieving the same, the ...performance of crude cellulases of
Aspergillus niger
JD-11 is explored for saccharification of untreated and pretreated (alkaline, dilute acid and steam) banana leaf waste. Therefore, to determine the best saccharifying conditions, the effects of various parameters such as enzyme loading (5–15 FPU/g), temperature (40–50 °C), surfactant addition (0.05–0.15% Tween 80 and PEG 6000) and substrate concentrations (2–6%) were studied at 150 rpm and pH 5.0. The crude cellulases yielded maximum reducing sugars (524.83 mg/g) from the dilute acid pretreated banana leaf waste at 45 °C, 15 FPU/g enzyme loading and 2% substrate loading in the presence of 0.15% PEG 6000 (w/v) as surfactant. The fermentation of enzymatic hydrolysate was carried out using initial reducing sugars concentration of 40 g/L in the medium at pH 5.5, 150 rpm and 30 °C for 30 h with the help of
Saccharomyces cerevisiae
. Ethanol production was estimated at every 6 h and maximum ethanol yield of 0.38 g/g sugar and productivity of 1.28 g/L/h was obtained after 12 h of fermentation of banana leaf waste hydrolysate. Thus, the easily obtained banana leaf waste could be a promising feedstock for bioethanol production.
Three different drought stress levels (water potential of the nutrient solution,
Ψ
s
=
−0.6, −1.2 and −1.8
MPa, respectively), and a control treatment (
Ψ
s
=
−0.1
MPa), were applied during 2 weeks ...to three almond species, followed by 3 weeks of recovery. The selected test species were
Prunus dulcis (Miller) D.Webb (bitter almond) and two wild almond species,
P. lycioides (Spach) C.K. Schneider and
P. scoparia (Spach) C.K. Schneider. All three are species native to Iran, and can be used as rootstock, but only
P. dulcis is actually used for commercial almond production.
In the absence of drought stress, maximum net assimilation rate (
A
max) is highest for
P. scoparia and lowest for
P. dulcis. For all species
A
max was above 16
μmol
CO
2
m
−2
s
−1. A similar relationship between
A
max and dark respiration rate (
R
d), was observed for all species. This relationship suggests that optimisation of the carbon budget is independent of species.
The three investigated species seem to have a different reaction to a similar stress, indicating different drought stress coping strategies.
P. scoparia lost all its leaves during the experiment, while
P. lycioides only kept some leaves, however, the remaining leaves were almost totally wilted and did not allow for any photosynthesis measurement.
P. scoparia did not recover during the experiment, as no new leaves were developed once
Ψ
s was restored to pre-drought stress levels. However, this species has green stems, indicating that stem photosynthesis might play an important role in the plants’ overall carbon balance. This species is an opportunistic one (
sensu Higgins, S.S., Larsen, F.E., Bendel, R.B., Radamaker, G.K., Bassman, J.H., Bidlake, W.R., Alwir, A., 1992. Comparative gas-exchange characteristics of potted, glasshouse-grown almond, apple, fig, grape, olive, peach and Asian pear. Sci. Hortic. 52 (4), 313–329), where assimilation is seriously limited by non-stomatal processes as evidenced by measurements of intercellular CO
2 concentration, eventually resulting in total leaf loss. All
P. lycioides leaves almost completely wilted during the experiment, but this species recovered rather quickly. Leaves, newly formed at the end of the experiment, obtained maximal assimilation rates under control
Ψ
s levels, equivalent to those measured in the control treatment. Finally,
P. dulcis did keep at least part of its leaves during drought stress. However, assimilation rates after 2 weeks of drought treatment and 3 weeks of recovery were only about half of those measured in the control treatment. Of the three investigated species, non-stomatal limitation of assimilation seems to be the least important in
P. dulcis.
Intrinsic water use efficiency, defined as the ratio of assimilation rate over stomatal conductance, increased for
P. dulcis with increasing drought stress, while a different pattern was observed for
P. lycioides and
P. scoparia, indicating non-stomatal processes prevail over stomatal limitations of the assimilation process. It was concluded that
P. dulcis is the species most tolerant to drought.
P. scoparia tries to avoid drought, whereas
P. lycioides has an intermediate behaviour. Besides
P. dulcis, also
P. lycioides seems to have some potential for use as rootstock for commercial almond production.
The present work aimed to evaluate the osmotic conditioning and shading on the germination and on the initial growth of aroeira seedlings. The seeds were pre-imbibed in solutions with different ...concentrations of PEG (polyethylene glycol) and KNO3 and incubated at 10°C and 20°C temperatures, during 0 (control), 12 and 24 hours. After these periods, the seeds were dried until they reached the initial levels of humidity. After that, they were put for germinating in BOD (Biochemical Oxygen Demand) chambers, at alternated 20-30°C. The control treatment and the pre-conditionings that presented the best results in BOD germination were selected, PEG (-1.0 MPa) + KNO3 (-1.0 MPa) and KNO3 (-1.0 MPa), with pre-imbibition for 12 h and incubated in BOD at 20°C. The seeds were sowed on trays and then they were transplanted, keeping under a net covered with 50% and 70% of shading and at sunlight. The osmotic conditioning did not change the seeds germination in BOD, but the highest aerial part size was observed in PEG -1.0 MPa + KNO3-1.0 MPa treatment. The shading levels at 50% and 70% and the osmotic conditioning with PEG -1.0 MPa + KNO3-1.0 MPa offered a higher emergence in a greenhouse condition; however, at sunlight the seeds presented a better index of quality on the 145th day.
This study focused on an investigation of the applicability of sucrose laurate as surfactant in solid dispersions. Although this surfactant has a US Drug Master File, it has not been used so far in ...internal pharmaceutical products. High drug-loaded solid dispersion systems consisting of gemfibrozil as a model drug and PEG 6000 as a carrier, with or without sucrose laurate (D1216), were prepared by the melting method. Cytotoxicity studies on Caco-2 monolayer cells were also performed, in order to gain information on the applicability of D1216 in oral formulations. The results showed that the presence of the surface-active agent did not affect the solid-state characteristics of the model drug significantly. A markedly improved dissolution of gemfibrozil from the ternary solid dispersion systems was observed as compared with the binary solid dispersion systems. The optimum concentration range of the D1216 in the formulations was determined to be 5–10%. The effective final concentrations of D1216 in the dissolution experiments proved to be non-toxic towards CaCo-2 cells. The results suggest the potential use of D1216 in innovative internal pharmaceutical formulations.
Poor solubility in aqueous medium limits the use of many drugs. Different methods have been adopted to promote the rate of dissolution of slightly water soluble drugs. Crystallization improves ...solubility, and bioavailability by increasing the surface area of slightly water soluble drugs. Pioglitazone (PGZ), which is a class II Biopharmaceutical Classification System drug has a slight solubility in water and a slow rate of dissolution, which may have a negative effect on its metabolism leading to a therapeutic failure.
The aim of this study was to improve the solubility of PGZ-HCl; an antidiabetic drug using precipitation method.
Formulations were prepared with polyethylene glycol 6000 and isomalt using different speed of homogenizer and quantity of solvent by precipitation method. Drug-polymer interactions were examined using differential scanning calorimetry (DSC), and Powder X-Ray Diffraction (PXRD). Surface structure were shown by SEM photographs.
The particle size was significantly decreased and solubility was enhanced with increase speed, ethanol solvent and increase stabilizer, however very high amount of stabilizer resulted in a decrease in solubility.
This result however showed that solid dispersion technique is a potential method for increasing dissolution profile of a poorly aqueous soluble agent.
Grass pea (Lathyrus sativus L.), a legume crop in arid and semi-arid areas, is widely acknowledged as highly drought tolerant. We report here an analysis of grass pea and garden pea seedlings ...stressed with 20% polyethylene glycol 6000 (PEG) for five days. While leaf margins of grass pea curled inward after PEG stress, leaves of pea failed to display this trait. PEG inhibited the growth of grass pea less than that of pea. Hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) accumulation increased in pea more than in grass pea. Greater accumulation of proline and soluble sugars alleviated osmotic stress injury to grass pea compared with pea. Moreover, PEG caused a significantly greater increase of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione peroxidase (GPX) activities in grass pea compared to pea. These enzymes showed obvious up-regulation at the transcriptional level in grass pea leaves. Together, these data suggest that the accumulation of osmoprotectants and the improvement of oxidation resistance resulted in the higher drought tolerance of grass pea compared to pea.
The article presents the research results of modifying antifreeze influence on the pore structure formation of dry mortars in terms of adhesive and base layers of external thermal insulation ...composite systems within different temperature regimes of hardening.
A disponibilidade hídrica é um dos principais fatores ambientais capaz de influenciar o processo de germinação de sementes. Nessas condições, a habilidade das sementes em manter sua viabilidade ...durante o armazenamento pode ser uma vantagem adaptativa de espécies encontradas em diferentes biomas, especialmente na caatinga. Objetivou-se, com este trabalho, avaliar a influência do armazenamento na tolerância das sementes de catingueira (Caesalpinia pyramidalis Tul.) à restrição hídrica, utilizando-se como agente osmótico o polietilenoglicol 6000 (PEG 6000). Sementes de catingueira foram armazenadas por 0, 3 e 6 meses em temperatura ambiente e acondicionadas em sacos de papel kraft, avaliando-se a influência dos diferentes potenciais osmóticos (0,0; -0,2; -0,4; -0,6; -0,8; -1,0 e -1,2 MPa) das soluções de PEG 6000 sobre a porcentagem de germinação (G%), no tempo médio de germinação (Tm), na velocidade média de germinação (Vm) e no índice de velocidade de germinação (IVG) das sementes. Observou-se que a interação entre o armazenamento e os tratamentos osmóticos influenciou significativamente as variáveis cinéticas de germinação avaliadas, exceto a Vm. Em todos os meses avaliados, a redução da água disponível no meio afetou no decréscimo da G%, da Vm e do IVG e na elevação do Tm das sementes. A tolerância à deficiência hídrica nas sementes de catingueira foi relativamente alta, tendo como limite a faixa entre -0,8 e -1,0 MPa. A identificação dos fatores ambientais que governam a germinação das sementes, como a disponibilidade hídrica, representa uma importante ferramenta na interpretação do comportamento ecológico das espécies em hábitats naturais.
The present work focused on the solubility enhancement of the poorly water-soluble anti-cancer agent camptothecin which, in its natural state, presents poor solubility inducing lack of activity with ...a marked toxicity. A new approach is adopted by using a ternary system including camptothecin (CPT) and cyclodextrins (CDs) dispersed in polyethylene glycol (PEG) 6000. Camptothecin solubility variations in the presence of α-CD, β-CD, γ-CD, hydroxypropyl-α-CD (HPα-CD), hydroxypropyl-β-CD (HPβ-CD), permethyl-β-CD (PMβ-CD) and sulfobutyl ether-β-CD (SBEβ-CD), were evaluated by Higuchi solubility experiments. In the second part, the most efficient camptothecin/P-CDs binary systems, mainly HPβ-CD and PMβ-CD, were dispersed in PEG 6000. In addition to a drug release and modeling evaluation, the CPT interactions with CDs and PEG 6000 to prepared the amorphous solid dispersion in the binary and ternary systems were investigated by Fourier transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analyses (TGA) and X-ray powder diffraction (XRPD). The results showed that HPβ-CD and PMβ-CD were the most efficient for camptothecin solubilization with highest apparent equilibrium constants. Dissolution studies showed that percentage of CPT alone after two hour in 0.1 M HCI medium, did not exceed 16%, whereas under the same conditions, CPT/PMβ-CD complex reached 76%. When dispersing the binary systems CPT/β-CDs in PEG 6000, the velocity and the percentage of CPT release were considerably improved whatever the CD used, reaching the same value of 85%. The binary and ternary systems characterization demonstrated that CPT inclused into the CDs cavity, replacing the water molecules. Furthermore, a drug transition from crystalline to amorphous form was obtained when solid dispersion is realized. The present work demonstrated that ternary complexes are promising systems for CPT encapsulation, and offer opportunities to use non toxic and commonly solubilizing carriers: βCD and PEG 6000 to improve bioavailability.
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