Effective diffusion coefficients and bioconversion rates of inhibitory compounds in flocs of Saccharomyces cerevisiae

Background: Fermentation strategies for bioethanol production that use flocculating Saccharomyces cerevisiae yeast need to account for the mechanism by which inhibitory compounds, generated in the hydrolysis of lignocellulosic materials, are tolerated and detoxified by a yeast floc. Results: Diffusion coefficients and first-order kinetic bioconversion rate coefficients were measured for three fermentation inhibitory compounds (furfural, hydroxymethylfurfural, and vanillin) in self-aggregated flocs of S. cerevisiae NRRL Y-265. Thièle-type moduli and internal effectiveness factors were obtained by simulating a simple steady-state spherical floc model. Conclusions: The obtained values for the Thiéle moduli and internal effectiveness factors showed that the bioconversion rate of the inhibitory compounds is the dominant phenomenon over mass transfer inside the flocs.

Modelamiento matemático de la cinética de secado de espagueti enriquecido con pulpa de zapallo deshidratada ( Cucurbita moschata ) / Mathematical modeling of spaghetti drying kinetics enriched with dehydrated squash pulp ( Cucurbita moschata )

RESUMEN A pesar que diversos estudios se han llevado a cabo sobre modelamiento matemático de las cinéticas de secado de espagueti, no se han desarrollado para espaguetis con sustitución de sémola de trigo Triticum durum por pulpa de zapallo deshidratada (PZD), por lo tanto, el objetivo de esta investigación fue modelar las cinéticas de secado de espagueti sustituido parcialmente con PZD (5 y 10g/100g harina), evaluar el efecto de la sustitución y la temperatura (50 y 60°C), sobre el tiempo de secado (contenido de humedad final = 0,13g/g b.s.), la difusividad efectiva (De) y algunas características que definen la calidad del producto (contenido de humedad, calidad de cocción y contenido de carotenoides totales). Para ello, se emplearon modelos matemáticos reportados en la literatura, como también la segunda ley de Fick, para un cilindro infinito. Los resultados mostraron que los modelos Henderson & Pabis y el Logarítmico presentaron mayor ajuste (R2 ≥ 0,90) a las cinéticas de secado experimentales; por el contrario, el modelo de Lewis presentó el menor ajuste. Se obtuvieron tiempos de secado de 5,00-4,10h, para las cinéticas realizadas a 50°C y tiempos de secado de 3,40-2,80h (aproximadamente), para las cinéticas a 60°C. De varió desde 1,50 hasta 2,50 x 10-7 cm2s-1, la cual, aumentó con la temperatura. En definitiva, la calidad del espagueti se afectó negativamente con el aumento de PZD y positivamente con el aumento de la temperatura de secado.

ABSTRACT Although several studies have been carried out on mathematical modeling of the spaghetti drying kinetics, they have not been developed for spaghetti with an incorporation of Triticum durum wheat semolina by dehydrated squash pulp (DSP). Therefore, the objective of this investigation was to model the kinetics of spaghetti drying partially substituted with DSP (5 and 10g/100g flour), to evaluate the effect of substitution and temperature (50 and 60°C), on the time of drying (final moisture content = 0.13g/g d.b.), the effective diffusivity (De) and some characteristics that define the quality of the product (moisture content, cooking quality and total carotenoid content). For this, mathematical models reported in the literature were used, as well as the second law of Fick for an infinite cylinder. The results showed that the Henderson & Pabis and the Logarithmic models presented greater adjustment (R2 ≥ 0.90) to the experimental drying kinetics. On the contrary, the Lewis model presented the smallest adjustment. Drying times of 5.00-4.10h were obtained for the kinetics carried out at 50°C and drying times of 3.40-2.80h (approximately) for the kinetics at 60°C. It varied from 1.50 to 2.50 x 10-7cm2s-1, which increased with temperature. Finally, the spaghetti quality was negatively affected with the increase in PZD and positively with the increase in the drying temperature.

Gray Matter Microstructural Abnormalities and Working Memory Deficits in Individuals with Schizophrenia

OBJECTIVE: Working memory impairments serve as prognostic factors for patients with schizophrenia. Working memory deficits are mainly associated with gray matter (GM) thickness and volume. We investigated the association between GM diffusivity and working memory in controls and individuals with schizophrenia. METHODS: T1 and diffusion tensor images of the brain, working memory task (letter number sequencing) scores, and the demographic data of 90 individuals with schizophrenia and 97 controls were collected from the SchizConnect database. T1 images were parcellated into the 68 GM Regions of Interest (ROI). Axial Diffusivity (AD), Fractional Anisotropy (FA), Radial Diffusivity (RD), and Trace (TR) were calculated for each of the ROIs. RESULTS: Compared to the controls, schizophrenia group showed significantly increased AD, RD, and TR in specific regions on the frontal, temporal, and anterior cingulate area. Moreover, working memory was negatively correlated with AD, RD, and TR in the lateral orbitofrontal, superior temporal, inferior temporal, and rostral anterior cingulate area on left hemisphere in the individuals with schizophrenia. CONCLUSION: These results demonstrated GM microstructural abnormalities in the frontal, temporal, and anterior cingulate regions of individuals with schizophrenia. Furthermore, these regional GM microstructural abnormalities suggest a neuropathological basis for the working memory deficits observed clinically in individuals with schizophrenia.

Characterization of the brain gray matter in amnestic mild cognitive impairmentby diffusion tensor imaging / 医学研究生学报

Objective Amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD)used to be evaluated by an-alyzing the characteristics of the brain gray matter via diffuse tensor imaging (DTI).This study was to characterize the damage to the mi-crostructural integrity of the brain gray matter in aMCI and AD patients using the mean diffusivity ( MD) of DTI and to investigateits transformation rules. Methods This retrospective study included 30 cases ofaMCI, 30 cases of AD, and another 30 normal controls. We measured the MD values of the whole brain gray matter , established the MD network of the water molecules in the gray matter , char-acterized the small-world network, and performed correlation analysis by neuropsychological assessment . Results Compared with the normal controls, the MDnetworks of the aMCI and AD groupsexhibited abnormal small world characteristics , namely, a higher clustering coefficient and a longer path , which reflected the damage to themicrostructure of the gray matter , and theaverage connectivity in the aMCI patients was lowerthan that in thenormal controls but higher than that in the AD group ( P<0.05) .The MD values of the gray matter were negatively correlated with the Montreal Cognitive Assessment Scale scores in the 11 hub regions of the brain , including the bilateral hippo-campus and the limbic system ( P<0.05) . Conclusion The diffusion feature of the water molecules in the brain gray matter of the aMCIpatient may help to detect early ADand reflect the damage to the brain microstructure in patients with neurodegenerative diseases .

Moisture Diffusivity in Chinese Herbal Medicine Ingredients / 世界科学技术-中医药现代化

This paper was aimed to study the moisture adsorption of Chinese herbal medicine ingredients at different environment.The film mass transfer model and Fick's second law were applied to evaluate the moisture diffusion for Chinese herbal medicine ingredients.The results showed that under the temperature of 25℃ and 50％ relative humidity,the diffusion coefficient of 13 medicine ingredients reached the highest.The diffusivity was controlled by film mass transfer.However,both film mass transfer and Fick's second law can be existed at the same time under different temperature and humidity.It was concluded that the diffusion of water in the traditional Chinese medicine might have been driven by a variety of diffusion mechanism,which was obviously affected by environmental factors.

Diffusion tensor imaging study of white matter fiber in patients with schizophrenia episode in early adulthood / 新乡医学院学报

Objective To explore the structure changes of white matter of the patients with schizophrenia episode in early adulthood by diffusion tensor imaging(DTI) and in order to provide a structural neuroimaging basis for understanding the pathology of schizophrenia.Methods Twenty-six patients with schizophrenia episode in early adulthood in the Second Affiliated Hospital of Xinxiang Medical University from July 2012 to March 2014 were selected as study group and twenty-eight healthy subjects whose age,sex,education were matched with study group were selected as control group.All subjects received structural magnetic resonance imaging and DTI scans.The fractional anisotropy (FA) and the mean diffusivity (MD) of the white matter of the same encephalic region were compared between the two groups by voxel-based analyses.Results The FA values of the right anterior cingulate gyrusthe,genu of corpus callosum,the right limb of internal capsule,the bilateral external capsule,the bilateral posterior of coronal radiate,the right anterior coronal radiate of patients in the study group were significantly lower than those in the control group (P ＜ 0.05).The MD values of the bilateral limbs of internal capsule,the right cingulate gyrus,left superior longitudinal tract,corpus callosum and right anterior coronal radiate of patients in the study group were significantly higher than those in the control group (P ＜ 0.05).Conclusion Schizophrenia patients who episode in early adulthood exist widespread microstructural damage of white matter.These changes may be related to the pathological change of schizophrenia.

Thermophysical properties of the pequi pulp in different concentrations / Propriedades termofísicas da polpa de pequi em diferentes concentrações

The pequi fruit (Caryocar coriaceum Wittm) has a great economic interest, regarding the use of its fruits in cooking as a source of vitamins and extraction of oils for the manufacture of cosmetics. However, are unknown studies on the thermophysical properties (specific heat, thermal diffusivity and thermal conductivity), in which properties are very important to the pulp being favored in an industrial level. The work in question was aimed at studying the physical properties of the pequi pulp with levels of total soluble solids of 6, 8, 10 and 12 °Brix. The physical properties were studied: specific heat, thermal diffusivity and thermal conductivity. The specific heat of the pulps was determined using the method of mixtures, the thermal diffusivity was determined using the method proposed by Dickerson and the thermal conductivity KD-2 equipment. Therefore, it was found that the specific heat tended to increase with the increase of temperature and total soluble solids content of the pulp. The thermal diffusivity of the pequi pulp decreased with the increase in total soluble solids; the thermal conductivity of the pulp did not show a definite increase in temperature trend in the pulps investigated.

O fruto do pequi (Caryocar coriaceum Wittm) possui um grande interesse econômico, no que se refere ao uso de seus frutos na culinária como fonte de vitaminas e na extração de óleos para a fabricação de cosméticos. Todavia, são desconhecidos estudos voltados para as propriedades termofísicas (calor específico, difusividade térmica e condutividade térmica), nas quais são propriedades de suma importância para que a polpa seja beneficiada a nível industrial. O trabalho em questão teve como objetivo estudar as propriedades físicas da polpa de pequi com teores de sólidos solúveis totais de 6, 8, 10 e 12 oBrix. As propriedades físicas estudadas foram: calor específico, difusividade térmica e condutividade térmica. O calor específico das polpas foi realizado por meio do calorímetro de mistura, a difusividade térmica utilizando-se o método do cilindro de Dickerson e a condutividade térmica no equipamento KD-2. Portanto, constatou-se que o calor específico apresentou tendência de aumento com o aumento da temperatura e do teor de sólidos solúveis totais das polpas. A difusividade térmica da polpa de pequi diminui com o aumento dos sólidos solúveis totais, a condutividade térmica das polpas não apresentou uma tendência definida com o aumento da temperatura nas polpas estudadas.

Accuracy of Diffusion Tensor Imaging for Diagnosing Cervical Spondylotic Myelopathy in Patients Showing Spinal Cord Compression

OBJECTIVE: To assess the performance of diffusion tensor imaging (DTI) for the diagnosis of cervical spondylotic myelopathy (CSM) in patients with deformed spinal cord but otherwise unremarkable conventional magnetic resonance imaging (MRI) findings. MATERIALS AND METHODS: A total of 33 patients who underwent MRI of the cervical spine including DTI using two-dimensional single-shot interleaved multi-section inner volume diffusion-weighted echo-planar imaging and whose spinal cords were deformed but showed no signal changes on conventional MRI were the subjects of this study. Mean diffusivity (MD), longitudinal diffusivity (LD), radial diffusivity (RD), and fractional anisotropy (FA) were measured at the most stenotic level. The calculated performance of MD, FA, MD∩FA (considered positive when both the MD and FA results were positive), LD∩FA (considered positive when both the LD and FA results were positive), and RD∩FA (considered positive when both the RD and FA results were positive) in diagnosing CSM were compared with each other based on the estimated cut-off values of MD, LD, RD, and FA from receiver operating characteristic curve analysis with the clinical diagnosis of CSM from medical records as the reference standard. RESULTS: The MD, LD, and RD cut-off values were 1.079 × 10⁻³, 1.719 × 10⁻³, and 0.749 × 10⁻³ mm²/sec, respectively, and that of FA was 0.475. Sensitivity, specificity, positive predictive value and negative predictive value were: 100 (4/4), 44.8 (13/29), 20 (4/20), and 100 (13/13) for MD; 100 (4/4), 27.6 (8/29), 16 (4/25), and 100 (8/8) for FA; 100 (4/4), 58.6 (17/29), 25 (4/16), and 100 (17/17) for MD∩FA; 100 (4/4), 68.9 (20/29), 30.8 (4/13), and 100 (20/20) for LD∩FA; and 75 (3/4), 68.9 (20/29), 25 (3/12), and 95.2 (20/21) for RD∩FA in percentage value. Diagnostic performance comparisons revealed significant differences only in specificity between FA and MD∩FA (p = 0.003), FA and LD∩FA (p < 0.001), FA and RD∩FA (p < 0.001), MD and LD∩FA (p = 0.024) and MD and RD∩FA (p = 0.024). CONCLUSION: Fractional anisotropy combined with MD, RD, or LD is expected to be more useful than FA and MD for diagnosing CSM in patients who show deformed spinal cords without signal changes on MRI.

Cinética de secagem de folhas de Solanum lycocarpum A. St.-Hil. (fruta-de-lobo) / Drying kinetics of leaves of Solanum lycocarpum A. St.-Hil. (wolf apple)

Objetivou-se neste trabalho determinar o tempo de secagem e modelar as curvas de secagem de folhas de fruta-de-lobo (Solanum lycocarpum A. St.-Hil.) secas em temperaturas de 40, 50 e 60ºC, num secador de leito fixo em camada fina com velocidade do ar de 0,81 m s-1, bem como estimar o coeficiente de difusão efetivo e a energia de ativação. Aos dados experimentais foram ajustados oito modelos matemáticos. As magnitudes do coeficiente de determinação (R²), do erro médio relativo (P) e do erro médio estimado (SE) foram utilizadas para verificar o grau de ajuste dos modelos. Concluiu-se que: a) O tempo de secagem diminuiu com o aumento da temperatura; b) os modelos de secagem Logaritmo e de Midilli et al. foram os que melhor se ajustaram aos dados experimentais; c) Os valores do coeficiente de difusão aumentaram de acordo com a elevação da temperatura do ar de secagem e d) O valor da energia de ativação para a folha Solanum lycocarpum A. St.-Hil. foi de 44, 60 kJ mol-1.

The aims of this study were to determine the drying time and the shape of the drying curves of leaves of wolf apple (Solanum lycocarpum A. St.-Hil.) dried at temperatures of 40, 50 and 60ºC in a thin layer fixed-bed dryer at air velocity of 0.81 m s-1, and to estimate the effective diffusion coefficient and activation energy. Eight mathematical models were fit to the experimental data. The magnitude of the coefficient of determination (R²), the mean relative error (P) and the estimated standard error (SE) were used to verify the fitting degree of the models. It was concluded that: a) The drying time decreased with increasing temperatures; b) the drying models of Logarithm and of Midilli et al. best fit to the experimental data; c) The values of the diffusion coefficient increased with the rising temperature of the drying air; d) The value of activation energy for the leaf of Solanum lycocarpum A. St.-Hil. was 44.60 kJ mol-1.

Abnormal Integrity of Corticocortical Tracts in Mild Cognitive Impairment: A Diffusion Tensor Imaging Study

Mild cognitive impairment (MCI) has been defined as a transitional state between normal aging and Alzheimer disease. Diffusion tensor imaging (DTI) can estimate the microstructural integrity of white matter tracts in MCI. We evaluated the microstructural changes in the white matter of MCI patients with DTI. We recruited 11 patients with MCI who met the working criteria of MCI and 11 elderly normal controls. The mean diffusivity (MD) and fractional anisotropy (FA) were measured in 26 regions of the brain with the regions of interest (ROIs) method. In the MCI patients, FA values were significantly decreased in the hippocampus, the posterior limb of the internal capsule, the splenium of corpus callosum, and in the superior and inferior longitudinal fasciculus compared to the control group. MD values were significantly increased in the hippocampus, the anterior and posterior limbs of the internal capsules, the splenium of the corpus callosum, the right frontal lobe, and in the superior and the inferior longitudinal fasciculus. Microstructural changes of several corticocortical tracts associated with cognition were identified in patients with MCI. FA and MD values of DTI may be used as novel biomarkers for the evaluation of neurodegenerative disorders.

Solubilidad y dffusividad de argón en soluciones acuosas de yoduro de tetrabutil amoiio / Solubiliy and diiffusivity of argon in aqueous solutions of tetrabutyl ammonium iodidesolutinss

En el presente trabajo se midió la solubilidad y la difusividad de Argón en agua y en soluciones acuosas de yoduro de tetrabutil amonio, a concentraciones de 0,02 m y 0,04 m y a temperaturas de 288.15 K y 298.15 K. Se describe el diseńo, construcción y calibración de un equipo para contacto gas-líquido, el cual cuenta con la instrumentación necesaria para el control de la temperatura, y la medida de la presión. El equipo construido permite evaluar la solubilidad y la difusividad a través del método de descenso de presión en celdas de diafragma. Las propiedades medidas permitieron comprobar el carácter hidrofóbico del catión [Bu]4N+.

In this work the solubility and the diffusivity of argon in water and in aqueous solutions of tetrabutyl ammonium iodide, at concentrations in the range 0.02 m to 0.04 m, were measured. Measurements were made at two temperatures: 288.15K and 298.15K. The design, construction and the calibration of a gas - liquid contact equipment is described. It uses auxiliary equipment for the measurement of pressure and the control of temperature. This apparatus allows the measurement of diffusivity and of solubility in diaphragm cells by the pressure decline method. The measured values of the properties confirm the hydrophobic character of the [Bu4N+] cation.

MR Diffusion Tensor Imaging in Optic Atrophy / 实用放射学杂志

Objective To study the MR diffusion tensor imaging(MR-DTI) feature of optic atrophy.Methods Diffusion tensor imaging data of optic nerve were acquired in twenty patients with optic atrophy and 20 healthy subjects.Results ①Atrophic optic nerves were thin obviously on MRI,and the signal of atrophic optic nerves decreased markedly on fractional anisotropy(FA) map and directionally encoded color(DEC) map.②The FA value(0.277?0.078) and ?∥ value(1.808?0.307) of atrophic optic nerves were declined obviously,and mean diffusivity(MD) value(1.442?0.264) and ?⊥ value(1.231?0.225) increased obviously in comparison to the normal optic nerves,there were statistically significant differences between the patients and the volunteers(P

Study on the removal of cresol for the agricultural waste water treatment / 日本農村医学会雑誌

Concerning the agricultural waste water treatment, adsorption removal of cresol which is one of disinfectants by commercial activated carbon was investigated.<BR>It was not found the significant correlation between amount of cresol adsorbed and physical properties of eight kinds of activated carbon. The intraparticle diffusivity of cresol onto the pores of activated carbon was significantly related to the mesopore volume.<BR>In the treatment of agricultural waste water, it is concluded that the activated carbon which is rich in mesopore volume is suitable for the adsorption removal of cresol from the standpoint of adsorption rate.