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Accurate temperature tracking for fast heating/cooling and regulation during the batch pretreatment of lignocellulosic biomass (LCB) is required to guarantee high product yield and quality repeatability. However, yield discrepancies are frequently found in the pretreatment literature in which temperature trajectory or heating sources details are seldom reported. Innacurate temperature control may be one of the reasons for these discrepancies. This paper proposes a tracking-regulation-tracking temperature control system for batch pretreatments of LCB heated by an electrical jacket heater. The accuracy of the control system in tracking the temperature set-point trajectory is measured with the weighted integral of the absolute error IAE ¯ . The controlled process performance was measured with the percentage difference between the experimental lignin recovery percentage and the value calculated with a steady-state mathematical model using the average temperature of the isothermal reaction period. The system was tested in an ethyl lactate-based 190 ∘ C, 1 L batch organosolv pretreatment with a maximum heating rate of 8.6 ∘ C/min and a mean cooling rate of -2.4 ∘ C/min. The process performance was 2.8% for an IAE ¯ of 1044 ∘ C/min thus confirming the efficacy of the proposed control system. [ABSTRACT FROM AUTHOR]

Purpose: Butanol is an interesting biofuel and a product precursor, that could be obtained with acetone and ethanol via fermentation. The biofuels production has been identified as not economically competitive, thus, the parallel production of high value-added products, such as xylitol, could be an alternative to improve the profit. Xylitol can be produced from xylose, which might be considered as a coproduct in a second generation biorefinery. Methods: This study presents a systematic biorefinery process design for the simultaneous acetone, butanol, ethanol (ABE) and xylitol production, based on experimental and simulation approaches. Experiments were performed for the pretreatment of sugarcane bagasse and ABE fermentation. The simulation part used the experimental results and experimental data from literature, to perform rigorous calculations of the ABE and xylitol production process. The economic analysis (EA) was performed relying on some indicators such as, the net present value (NPV) and payback period (PBP); EA includes several scenarios for producing only ABE and some scenarios for simultaneous ABE and xylitol production. Results: The results showed that the combined butanol and xylitol production could reduce by 17% the selling price of butanol, compared with only producing butanol. The study also included the combustion of residual solids and carbon dioxide depletion analyses. Conclusion: This approach illustrates the opportunity to perform a rigorous techno-economic analysis, to identify the feasibility of the process at industrial scale, based on realistic data. This approach was implemented for ABE and xylitol production, but it can be used to any other bioproduct. [ABSTRACT FROM AUTHOR]

We prove that there exists no irreducible representation of the identity component of the isometry group PO (1 , n) of the real hyperbolic space of dimension n into the group O (2 , ∞) if n ≥ 3 . This is motivated by the existence of irreducible representations (arising from the spherical principal series) of PO (1 , n) ∘ into the groups O (p , ∞) for other values of p. [ABSTRACT FROM AUTHOR]

Objectives: To assess the effect of one-step temperature increase, from 35 to 55 °C, on the methane production of a mesophilic granular sludge (MGS) treating wine vinasses and the effluent of a hydrogenogenic upflow anaerobic sludge blanket (UASB) reactor.Results: One-step temperature increase from mesophilic to thermophilic conditions improved methane production regardless of the substrate tested. The biomethane potentials obtained under thermophilic conditions were 1.8-2.9 times higher than those obtained under mesophilic conditions. The MGS also performed better than an acclimated thermophilic digestate, producing 2.2-2.5 times more methane than the digestate under thermophilic conditions. Increasing the temperature from 35 to 55 °C also improved the methane production rate of the MGS (up to 9.4 times faster) and reduced the lag time (up to 1.9 times). Although the temperature increase mediated a decrease in the size of the sludge granules, no negative effects on the performance of the MGS was observed under thermophilic conditions.Conclusions: More methane is obtained from real agroindustrial effluents at thermophilic conditions than under mesophilic conditions. One-step temperature increase (instead of progressive sequential increases) can be used to implement the thermophilic anaerobic digestion processes with MGS. [ABSTRACT FROM AUTHOR]

Growth arrest specific 1 (GAS1) is a GPI-anchored protein that inhibits proliferation when overexpressed in tumors but during development it promotes proliferation and survival of different organs and tissues. This dual ability is caused by its capacity to interact both by inhibiting the signaling induced by the glial cell line-derived neurotrophic factor and by facilitating the activity of the sonic hedgehog pathway. GAS1 is expressed as membrane bound in different organs and as a secreted form by glomerular mesangial cells. In the developing central nervous system, GAS1 is found in neural progenitors; however, it continues to be expressed in the adult brain. Here, we demonstrate that soluble GAS1 is present in the cerebrospinal fluid (CSF) and it is expressed in the choroid plexus (CP) of the adult rat, the main producer of CSF. Additionally, we confirm the presence of GAS1 in blood plasma and liver of the adult rat, the principal source of blood plasma proteins. The pattern of expression of GAS1 is perivascular in both the CP and the liver. In vitro studies show that the fibroblast cell line NIH/3T3 expresses one form of GAS1 and releases two soluble forms into the supernatant. Briefly, in the present work, we show the presence of GAS1 in adult rat body fluids focusing in the CSF and the CP, and suggest that secreted GAS1 exists as two different isoforms. [ABSTRACT FROM AUTHOR]

This work studies the effect of initial solid load (4-32 %; w/v, DS) and particle size (0.41-50 mm) on monosaccharide yield of wheat straw subjected to dilute HSO (0.75 %, v/v) pretreatment and enzymatic saccharification. Response surface methodology (RSM) based on a full factorial design (FFD) was used for the statistical analysis of pretreatment and enzymatic hydrolysis. The highest xylose yield obtained during pretreatment (ca. 86 %; of theoretical) was achieved at 4 % (w/v, DS) and 25 mm. The solid fraction obtained from the first set of experiments was subjected to enzymatic hydrolysis at constant enzyme dosage (17 FPU/g); statistical analysis revealed that glucose yield was favored with solids pretreated at low initial solid loads and small particle sizes. Dynamic experiments showed that glucose yield did not increase after 48 h of enzymatic hydrolysis. Once established pretreatment conditions, experiments were carried out with several initial solid loading (4-24 %; w/v, DS) and enzyme dosages (5-50 FPU/g). Two straw sizes (0.41 and 50 mm) were used for verification purposes. The highest glucose yield (ca. 55 %; of theoretical) was achieved at 4 % (w/v, DS), 0.41 mm and 50 FPU/g. Statistical analysis of experiments showed that at low enzyme dosage, particle size had a remarkable effect over glucose yield and initial solid load was the main factor for glucose yield. [ABSTRACT FROM AUTHOR]

Potatoes play the role of a vegetable or a complementary dish in the Mexican diet. They are mainly consumed fresh. Dried vegetables of the particular interest in preparation of dry mixtures are used for soups. The rapid expansion of the fast food industry could result in an increase in the use of dehydrated potatoes, as a component for vegetable mixture and soups. However, Pre-drying treatments such as addition of antioxidants are needed for vegetable drying as the potato in order to avoid changes of color. In this work, the influence of different pre-treatments and drying conditions on physical characteristics (moisture content, water activity and color difference) of thinly sliced potato during drying by fluidized bed was investigated. The thinly sliced samples of fresh potato were dipped into solutions containing citric acid (0, 0.5 and 1 % w/w) before drying. Potato sample were dehydrated at air temperatures of 40, 50 and 60 °C. The second degree polynomial model was used to describe the response variables. The analysis of variance (ANOVA) for all coded models indicated that the models were statistically significant ( p ≤ 0.05). The temperature and citric acid increment increases color difference, and decreases the moisture content and water activity of the dehydrated samples of potato. Color closest to the original color of fresh potato was obtained in some treatments. In general, it was observed that the drying of thinly sliced potato was influenced by pretreatment. Las papas juegan un papel como verdura o como guarnición en la dieta Mexicana. Son consumidas principalmente en fresco. En sopas se usan vegetales deshidratados de interés particular en la preparación de mezclas secas. La rápida expansión en la industria de la comida rápida pudiera resultar en un aumento en el uso de papas deshidratadas, como un componente de mezcla de vegetales y sopas. No obstante, los tratamientos de pre-secado, como la adición de antioxidantes, son necesarios para el deshidratado de verduras como la papa, a fin de evitar cambios de color. En este trabajo, se investigó la influencia de diferentes pre-tratamientos y condiciones de secado en las características físicas (contenido de humedad, actividad del agua y diferencia en color) de papa rebanada muy delgada durante el deshidratado mediante cama fluidizada. Las muestras de rebanadas delgadas de papa fresca fueron inmersas en soluciones que contenían ácido cítrico (0, 0.5, y 1% p/v) antes del secado. Las muestras de papa se deshidrataron a temperaturas del aire de 40, 50, y 60 °C. Se usó un modelo polinomial de segundo grado para describir las variables-respuestas. El análisis de varianza (ANAVA) para todos los modelos codificados indicaron que los modelos fueron estadísticamente significativos ( p≤0.05). El aumento en la temperatura y el ácido cítrico incrementan la diferencia en color y disminuyen el contenido de humedad y actividad del agua de las muestras deshidratadas de papa. En algunos tratamientos se obtuvo un color cercano al original de la papa fresca. En general, se observó que el secado de rebanadas finas de papa estuvo influenciado por el pre-tratamiento. [ABSTRACT FROM AUTHOR]

The rheological behavior of a cetylpyridinium chloride 100 mmol l–1/sodium salicylate 60 mmol l–1 aqueous solution was studied in this work under homogeneous (cone and plate) and non-homogeneous flow conditions (vane-bob and capillary rheometers), respectively. Instabilities consistent with non-monotonic flow curves were observed in all cases and the solution exhibited similar behavior under the different flow conditions. Hysteresis and the sigmoidal flow curve suggested as characteristic of systems that show constitutive instabilities were observed when running cycles of increasing and decreasing stress or shear rate, respectively. This information, together with a detailed determination of steady states at shear stresses close to the onset of the instabilities, allowed one to show unequivocally that "top and bottom jumping" are the mechanisms to trigger the instabilities in this micellar system. It is shown in addition that there is not a true plateau region in between the "top and bottom jumping". Finally, the flow behavior beyond the upturn seemed to be unstable and was found accompanied by an apparent violation of the no-slip boundary condition. [ABSTRACT FROM AUTHOR]

We determined the enzymatic activity and crude subcellular distribution of four exopeptidases: Dipeptidylaminopeptidase IV (DAP-IV), Alanyl aminopeptidase (AAP), Prolyl aminopeptidase (PAP) and γ-Glutamyl transpeptidase (γGTP), and two endopeptidases: Postproline endopeptidase (PEP) and “Trypsin-like” peptidase (“T-L” P) in pars compacta (SNPC) and pars reticulata (SNPR) of substantia nigra, caudate-putamen (CAU) and cerebral cortex (CC) of the rat brain. We found: 1) DAP-IV activity is comparatively higher in SNPC and it is equally distributed in the postmitochondrial precipitate (PR) and supernatant (SN) fractions of SNPC, CAU and CC but higher in the SN from SNPR. 2) CC shows the highest activity of AAP and its activity is mainly located in the SN from all areas. 3) The activity of PAP is comparatively higher in SNPC and it is exclusively located in the SN from all areas. 4) γGTP activity is similar in all areas but its predominance is in the SN for SNPC and SNPR, and in the PR for CAU and CC. 5) CAU has higher PEP activity (higher in the PR) than CC (higher in the SN); no activity is detected in the substantia nigra. 6) The activity of a “Trypsin-like” peptidase is the highest in SNPC and SNPR; this activity have some predominance in the SN and higher predominance in the same fraction from CAU and CC. [ABSTRACT FROM AUTHOR]

An analysis of the flow of polymer solutions through capillaries by means of pressure profiles was performed in this work. The experiments were carried out with aqueous solutions of flexible and semirigid macromolecules, Polyox and Xanthan respectively. The influence of the macromolecules' conformation on the flow field development is reflected on the different magnitudes of the entry length, being of the order of 60 diameters for the solutions of rigid macromolecules, and of the order of 10 diameters for flexible ones. In addition, the calculated end effects were larger for the rigid macromolecules than for the flexible ones. From these results, it is found that an increase in the entrance length is observed when the pseudoplastic behavior of the polymer solutions is increased. [ABSTRACT FROM AUTHOR]