Interactions between Proteins and the Membrane Surface in Multiscale Modeling of Organic Fouling.

In the present paper, an improved multiscale modeling aimed at describing membrane fouling in the UltraFiltration (UF) process was proposed. Some of the authors of this work previously published a multiscale approach to simulate ultrafiltration of Bovine Serum Albumin (BSA) aqueous solutions. However, the noncovalent interactions between proteins and the membrane surface were not taken into account in the previous formulation. Herein, the proteins-surface interactions were accurately computed by first-principle-based calculations considering also the effect of pH. Both the effective surface of polysulfone (PSU) and the first layer of proteins adsorbed on the membrane surface were accurately modeled. Different from the previous work, the equilibrium distance between proteins was calculated and imposed as lower bound to the protein-protein distances in the compact deposit accumulated on the membrane surface. The computed BSA surface charges were used to estimate the protein potential and the charge density, both necessary to formulate a forces balance at microscopic scale. The protein surface potential was compared with Z-potential measurements of BSA aqueous solution, and a remarkable agreement was found. Finally, the overall additional resistance, as due to both the compact and loose layers of the deposit, was computed, thus allowing the final transition to a macroscopic scale, where an unsteady-state mass transfer model was formulated to describe the behavior of a typical dead-end UF process. A good agreement between simulated and experimental permeate flux decays was observed.

High Blood Pressure States in Children, Adolescents, and Young Adults Associate Accelerated Vascular Aging, with a Higher Impact in Females' Arterial Properties.

The aims of the study were to determine (1) whether the presence of High blood pressure (HBP) states in the youth associate a steeper rate of age-related change in arterial geometrical and wall properties with respect to subjects with no previous cardiovascular risk factor (CRF) exposure, (2) in which parameters and in what magnitude, and (3) the existence of a gender-related difference in the impact of this condition on arterial properties. 300 individuals (mean/range: 15/4-29 years; 133 females) were included. Two groups were assembled: (1) Reference: nonprevious exposure to traditional CRF and (2) HBP: subjects with arterial hypertension and/or elevated blood pressure (BP) levels during the study. Additionally, HBP subjects were separated in BP-related subgroups. Measured parameters were (1) central (aortic) arterial BP and aortic pulse wave analysis parameters, (2) carotid and femoral artery local (pressure-strain elastic modulus) and regional (pulse wave velocity; PWV) stiffness, and (3) arterial diameters and carotid intima-media thickness (CIMT). Age-related changes in these parameters (absolute values and z-scores) were explored by obtaining simple linear regression models for each group. HBP presented a steeper rate of change (accelerated vascular aging; VA) for most of the parameters assessed, mainly in central (aortic) hemodynamics. VA increased as the HBP level got higher. Both males' and females' aging rates were affected by this condition, but females presented a more marked relative age-related increase with HBP exposure. HBP states in the youth gradually associate accelerated VA, with a progressive hemodynamic-structural-functional onset of damage, with females presenting a more marked relative HBP-associated arterial repercussion.

Growing-Related Changes in Arterial Properties of Healthy Children, Adolescents, and Young Adults Nonexposed to Cardiovascular Risk Factors: Analysis of Gender-Related Differences.

The aims of our work were to determine normal aging rates for structural and functional arterial parameters in healthy children, adolescents, and young adults and to identify gender-related differences in these aging rates. Methods. 161 subjects (mean: 15 years (range: 4-28 years), 69 females) were studied. Subjects included had no congenital or chronic diseases, nor had they been previously exposed to traditional cardiovascular risk factors. Arterial parameters assessed were (1) central blood pressure (BP) and aortic pulse wave analysis, (2) arterial local (pressure-strain elastic modulus) and regional (pulse wave velocity, PWV) stiffness, and (3) arterial diameters and carotid intima-media thickness (CIMT). Simple linear regression models (age as the independent variable) were obtained for all the parameters and the resulting rates of change were compared between genders. Results. No gender-related differences were found in mean values of arterial structural and functional parameters in prepubertal ages (4-8 years), but they started to appear at ~15 years. Boys showed a greater rate of change for central systolic BP, central pulse pressure, CIMT, and carotid-femoral PWV. Conclusion. Gender-related differences in arterial characteristics of adults can be explained on the basis of different growing-related patterns between boys and girls, with no existing differences in prepubertal ages.

Nanofiltration based water reclamation from tannery effluent following coagulation pretreatment.

Coagulation-nanofiltration based integrated treatment scheme was employed in the present study to maximize the removal of toxic Cr(VI) species from tannery effluents. The coagulation pretreatment step using aluminium sulphate hexadecahydrate (alum) was optimized by response surface methodology (RSM). A nanofiltration unit was integrated with this coagulation pre-treatment unit and the resulting flux decline and permeate quality were investigated. Herein, the coagulation was conducted under response surface-optimized operating conditions. The hybrid process demonstrated high chromium(VI) removal efficiency over 98%. Besides, fouling of two of the tested nanofiltration membranes (NF1 and NF3) was relatively mitigated after feed pretreatment. Nanofiltration permeation fluxes as high as 80-100L/m(2)h were thereby obtained. The resulting permeate stream quality post nanofiltration (NF3) was found to be suitable for effective reuse in tanneries, keeping the Cr(VI) concentration (0.13mg/L), Biochemical Oxygen Demand (BOD) (65mg/L), Chemical Oxygen Demand (COD) (142mg/L), Total Dissolved Solids (TDS) (108mg/L), Total Solids (TS) (86mg/L) and conductivity levels (14mho/cm) in perspective. The process water reclaiming ability of nanofiltration was thereby substantiated and the effectiveness of the proposed hybrid system was thus affirmed.

Enzymatic transesterification of waste vegetable oil to produce biodiesel.

An experimental study on enzymatic transesterification was performed to produce biodiesel from waste vegetable oils. Lipase from Pseudomonas cepacia was covalently immobilized on a epoxy-acrylic resin support. The immobilized enzyme exhibited high catalytic specific surface and allowed an easy recovery, regeneration and reutilisation of biocatalyst. Waste vegetable oils - such as frying oils, considered not competitive with food applications and wastes to be treated - were used as a source of glycerides. Ethanol was used as a short chain alcohol and was added in three steps with the aim to reduce its inhibitory effect on lipase activity. The effect of biocatalyst/substrate feed mass ratios and the waste oil quality have been investigated in order to estimate the process performances. Biocatalyst recovery and reuse have been also studied with the aim to verify the stability of the biocatalyst for its application in industrial scale.

Response surface-optimized removal of Reactive Red 120 dye from its aqueous solutions using polyethyleneimine enhanced ultrafiltration.

Retention of toxic dyes with molecular weights lower than the molecular weight cut-off (MWCO) of the ultrafiltration membranes can be improved through selective binding of the target dyes to a water-soluble polymer, followed by ultrafiltration of the macromolecular complexes formed. This method, often referred to as polymer enhanced ultrafiltration (PEUF), was investigated in the present study, using polyethyleneimine (PEI) as the chelating agent. Model azo dye Reactive Red 120 was selected as the poorly biodegradable, target contaminant, because of its frequent recalcitrant presence in colored effluents, and its eventual ecotoxicological impacts on the environment. The effects of the governing process factors, namely, cross flow rate, transmembrane pressure polymer to dye ratio and pH, on target dye rejection efficiency were meticulously examined. Additionally, each parameter level was statistically optimized using central composite design (CCD) from the response surface methodology (RSM) toolkit, with an objective to maximize performance efficiency. The results revealed high dye retention efficiency over 99%, accompanied with reasonable permeate flux over 100L/m(2)h under optimal process conditions. The estimated results were elucidated graphically through response surface (RS) plots and validated experimentally. The analyses clearly established PEUF as a novel, reasonably efficient and economical route for recalcitrant dye treatment.

Use of continuous lactose fermentation for ethanol production by Kluveromyces marxianus for verification and extension of a biochemically structured model.

A biochemically structured model has been developed to describe the continuous fermentation of lactose to ethanol by Kluveromyces marxianus and allowed metabolic coefficients to be determined. Anaerobic lactose-limited chemostat fermentations at different dilution rates (0.02-0.35h(-1)) were performed. Species specific rates of consumption/formation, as well as yield coefficients were determined. Ethanol yield (0.655 C-mol ethanol(∗)C-mol lactose(-1)) was as high as 98% of theoretical. The modeling procedure allowed calculation of maintenance coefficients for lactose consumption and ethanol production of m(s)=0.6029 and m(e)=0.4218 (C-mol) and (C-molh)(-1), respectively. True yield coefficients for biomass, ethanol and glycerol production were calculated to be Y(true)(sx)=0.114, Y(true)(ex)=0.192 and Y(sg)=2.250 (C-mol) and (C-mol)(-1), respectively. Model calculated maintenance and true yield coefficients agreed very closely with those determined by regressions of the experimental data. The model developed provides a solid basis for the rational design of optimised fermentation of cheese whey.

Worldwide distribution of PSEN1 Met146Leu mutation: a large variability for a founder mutation.

OBJECTIVE: Large kindreds segregating familial Alzheimer disease (FAD) offer the opportunity of studying clinical variability as observed for presenilin 1 (PSEN1) mutations. Two early-onset FAD (EOFAD) Calabrian families with PSEN1 Met146Leu (ATG/CTG) mutation constitute a unique population descending from a remote common ancestor. Recently, several other EOFAD families with the same mutation have been described worldwide. METHODS: We searched for a common founder of the PSEN1 Met146Leu mutation in families with different geographic origins by genealogic and molecular analyses. We also investigated the phenotypic variability at onset in a group of 50 patients (mean age at onset 40.0 +/- 4.8 years) by clinical, neuropsychological, and molecular methodologies. RESULTS: EOFAD Met146Leu families from around the world resulted to be related and constitute a single kindred originating from Southern Italy before the 17th century. Phenotypic variability at onset is broad: 4 different clinical presentations may be recognized, 2 classic for AD (memory deficits and spatial and temporal disorientation), whereas the others are expressions of frontal impairment. The apathetic and dysexecutive subgroups could be related to orbital-medial prefrontal cortex and dorsolateral prefrontal cortex dysfunction. CONCLUSIONS: Genealogic and molecular findings provided evidence that the PSEN1 Met146Leu families from around the world analyzed in this study are related and represent a single kindred originating from Southern Italy. The marked phenotypic variability might reflect early involvement by the pathologic process of different cortical areas. Although the clinical phenotype is quite variable, the neuropathologic and biochemical characteristics of the lesions account for neurodegenerative processes unmistakably of Alzheimer nature.

Factor analysis of transesterification reaction of waste oil for biodiesel production.

In the present paper a factor analysis is presented for the enzymatic transesterification of waste oil for biodiesel production. The experimental data on batch reactor evidence two key variables: enzyme loading and mixing conditions. These variables were subjected to a factor analysis and their combined effect on the reaction performance was determined. Response surface methodology (RSM) was used based on a linear first order model (steepest ascent method) and on a second order one in proximity of the optimal solution. The result was a model able to predict reaction performance within the range of mixing rates and enzyme amount considered for model formulation and outside of it, as shown in the final validation. Best performances were obtained at high stirring and high enzyme loading.

Heterogeneity within a large kindred with frontotemporal dementia: a novel progranulin mutation.

BACKGROUND: Frontotemporal dementia (FTD) in several 17q21-linked families was recently explained by truncating mutations in the progranulin gene (GRN). OBJECTIVE: To determine the frequency of GRN mutations in a cohort of Caucasian patients with FTD without mutations in known FTD genes. METHODS: GRN was sequenced in a series of 78 independent FTD patients including 23 familial subjects. A different Calabrian dataset (109 normal control subjects and 96 FTD patients) was used to establish the frequency of the GRN mutation. RESULTS: A novel truncating GRN mutation (c.1145insA) was detected in a proband of an extended consanguineous Calabrian kindred. Segregation analysis of 70 family members revealed 19 heterozygous mutation carriers including 9 patients affected by FTD. The absence of homozygous carriers in a highly consanguineous kindred may indicate that the loss of both GRN alleles might lead to embryonic lethality. An extremely variable age at onset in the mutation carriers (more than five decades apart) is not explained by APOE genotypes or the H1/H2 MAPT haplotypes. Intriguingly, the mutation was excluded in four FTD patients belonging to branches with an autosomal dominant mode of inheritance of FTD, suggesting that another novel FTD gene accounts for the disease in the phenocopies. It is difficult to clinically distinguish phenocopies from GRN mutation carriers, except that language in mutation carriers was more severely compromised. CONCLUSION: The current results imply further genetic heterogeneity of frontotemporal dementia, as we detected only one GRN-linked family (about 1%). The value of discovering large kindred includes the possibility of a longitudinal study of GRN mutation carriers.

The effects of APOE and tau gene variability on risk of frontotemporal dementia.

Frontotemporal dementia (FTD) is a complex dementing syndrome whose genetic/non genetic risk factors are mostly unknown. Aim of the present work was to investigate whether APOE and/or tau gene variability does affect the risk of FTD. A sample of FTD cases (sporadic: n = 54; familial: n = 46, one subject per family) was collected in a genetically homogeneous population (Calabria, southern Italy) and analyzed in comparison with an age- and sex-matched control group (n = 180) extracted from the same population. Logistic regression analysis showed that APOE gene variability affects the probability of disease, with allele epsilon4 increasing (exp(beta1) = 2.68 with [1.51-4.76] 95% confidence interval; p = 0.001) and allele epsilon2 decreasing (exp(beta1) = 0.28 with [0.12-0.66] 95% confidence interval; p = 0.003) the risk of FTD. On the contrary, tau gene variability was ineffectual (exp(beta1) non significantly different from 1 for either H1 or H2 haplotypes), although a small effect was observed by the H1 haplotype in increasing the protective effect of the epsilon2 allele (p = 0.007).

A large Calabrian kindred segregating frontotemporal dementia.

Frontotemporal dementia (FTD) displays significant neuropathological and genetic heterogeneity among and within affected families. An early diagnosis is often difficult because cognitive symptoms are manifest only at a late stage of the disease. We have been studying a large pedigree segregating frontotemporal dementia (FTD) to which belong 34 identified affected persons, 11 of whom were personally examined. The kindred has been genealogically reconstructed; all FTD patients have been linked to the same ancestors who lived in the early 18(th) century (11 generations before the present one). Autosomal dominant transmission was evident. Clinical features were uniform within the kindred and met the Lund-Manchester criteria. Personality changes with absence of insight, lack of empathy and of social awareness manifested up to 5 years before medical advice was sought. Loss of fluency was the earliest neuropsychological sign, in the absence of memory, orientation and praxis deficits, which evolved late, together with hyperorality. Akinesia was observed early, rigidity appeared late, tremor was absent. Two patients showed myoclonus late in their evolution. No ALS signs were observed in this kindred. Mutations of the MAPt gene, coding for the Tau protein, were not detected in affected family members. Linkage studies excluded chromosomes 3 and 9 and gave indeterminate results that were model dependent for chromosome 17.