27 research outputs found

    Permeate flux and fouling resistance in ultrafiltration of depectinized apple juice using ceramic membranes

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    Raw depectinized apple juice was clarified in a laboratory scale ultrafiltration system using ceramic tubular membranes (Tech-Sep Carbosep) with a molecular weight cut-off of 300,000, 50,000, and 30,000 Da. The experiments have been carried out over a wide range of transmembrane pressures (100–400 kPa), temperatures (20–55 °C), and feed flow rates (100–900 ml/min). Permeate flux significantly decreased with time until a steady-state was established. The steady-state permeate flux reached a maximum at a transmembrane pressure of about 200 kPa. Higher permeate flux was obtained at higher temperatures due to lower permeate viscosity. The steady-state permeate flux was proportional to the feed flow rate raised to powers ranging between 0.22 and 0.31. All the membranes studied produced the clarified juice with a satisfactory clarity and color intensity value

    Clarification of red raspberry juice using microfiltration with gas backwashing: a viable strategy to maximize permeate flux and minimize a loss of anthocyanins

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    Red raspberry (Rubus idaeus) juice was produced by maceration of raspberry pulp at 50 °C for 2 h using 400 mg kg Klerzyme150 enzymatic pectolitic preparation followed by raw juice clarification with gelatin and bentonite or cross-flow membrane filtration. A minimal loss of anthocyanins from 630 to 540 mg l was obtained when the juice was clarified using a ceramic multichannel microfilter (MF) with a pore size of 0.2 μm. A light transmission at 625 nm in MF permeate was above 85% and the residual pectin (900 mg l) was completely removed. During ultrafiltration through ceramic or polysulfone membranes with a molecular weight cut-off of 30-300 kDa, the content of anthocyanins was reduced to 220-370 mg l, but a light transmission at 625 nm was as high as 96%. The permeate flux in MF was maintained at high values above 170 l m h at 3 bar for more than 2 h by backwashing the membrane with a compressed air every 6 min for 1 min. The cake compression at high pressures was avoided by short filtration times between backwashing

    Investigations of hydrodynamic permeability of ceramic and polysulfone membranes for microfiltration and ultrafiltration

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    The aim of this research was to compare the hydraulic resistance of several commercial ultrafiltration and microfiltration membranes. The hydraulic resistance for each membrane was calculated from the pure water permeation data collected at various transmembrane pressures and temperatures to check the effects of these parameters on the membrane resistance. The experiments have been carried out in a laboratory crossflow UF/MF equipment for clarification of fruit juices. This paper introduces the experimental results showing the influence of operating parameters, such as feed flow rate, temperature, pressure difference in the microfiltration and ultrafiltration through the ceramic Kerasep membrane (pore size 0.2 μm, Tech-Sep, Miribel, France), Carbosep M9 and M7 membrane (molecular weight cut-off of 300 and 30 kg/mol, Tech-Sep, Miribel, France) and polysulfone membranes (molecular weight cut-off of 30 kg/mol, Frenesius, Germany). The results confirmed our earlier work [1] but we provide here many additional results. The hydraulic resistance Rm was 0.65, 3.56, and 0.05 × 1013 1/m for Carbosep M7, Carbosep M9 and Kerasep membrane, respectively. The hydraulic resistance of these membranes does not depend on the operating pressure, which means that the membranes are incompressible. The hydraulic resistance of a polysulfone hollow fiber membrane slightly increased with increasing the applied pressure difference. The Rm values were in the range of (0.61 – 0.92) ⋅1013 1/m, and the applied pressure difference was in the range of (0.225 – 0.900) bar, which is an indication that this membrane was compressible

    New herbal bitter liqueur with high antioxidant activity and lower sugar content: innovative approach to liqueurs formulations

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    Herbal liqueurs are spirits with numerous functional properties, due to the presence of bioactive extractable compounds deriving from herbs. The aim of this study was to obtain new herbal bitter liqueur (HBL) on the basis of twelve selected bitter and aromatic plants extracts, with an optimal sensory profile for consumer acceptance. Also, the determination of optimal sugar content in HBL was done. Furthermore, antioxidant (AO) capacity and total phenolic content (TPC) of HBL was evaluated and compared to similar commercial herbal spirits. Among five tested formulations, assessed by 9-point hedonic scale, HBL with the ratio of bitter and aromatic plants 1:4 was the most acceptable. Ideal concentration of sugar in HBL, determined using a just-about-right scale, was found to be 80.32 g/l of sucrose, which is approximately 20% less than the minimum stipulated by European Union Regulation and several times lower than in the majority of commercial liqueurs. Obtained result indicates the possibility of sugar reduction in liqueurs, and suggests the need to carry out sensory analysis before production of these high-calorie beverages. Radical scavenging ability against DPPH and ABTS radicals, as well as ferric reducing antioxidant power and TPC of HBL were convincingly superior in comparison to similar commercial herbal alcoholic beverages. High correlation coefficients between TPC and other assays applied strongly support the significant role of the polyphenols in the total AO capacity of the HBL and other tested commercial herbal spirits. Headspace GC/MS revealed that the most abundant terpenes were menthone (3.75%), eucalyptol (3.42%) and menthol (3.10%), whereas methanol was present in a small amount (4.97 mg/l)

    Supplementing essential amino acids with the nitric oxide precursor, l-arginine, enhances skeletal muscle perfusion without impacting anabolism in older men

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    Postprandial limb blood flow and skeletal muscle microvascular perfusion reduce with aging. Here we tested the impact of providing bolus essential amino acids (EAA) in the presence and absence of the nitric oxide precursor, l-Arginine (ARG), upon skeletal muscle blood flow and anabolism in older men. Healthy young (YOUNG: 19.7 ± 0.5 y, N = 8) and older men (OLD, 70 ± 0.8 y, N = 8) received 15 g EAA or (older only) 15 g EAA +3 g ARG (OLD-ARG, 69.2 ± 1.2 y, N = 8). We quantified responses in muscle protein synthesis (MPS; incorporation of 13C phenylalanine into myofibrillar proteins), leg and muscle microvascular blood flow (Doppler/contrast enhanced ultrasound (CEUS)) and insulin/EAA in response to EEA ± ARG. Plasma EAA increased similarly across groups but argininemia was evident solely in OLD-ARG (∼320 mmol, 65 min post feed); increases in plasma insulin (to ∼13 IU ml−1) were similar across groups. Increases in femoral flow were evident in YOUNG >2 h after feeding; these effects were blunted in OLD and OLD-ARG. Increases in microvascular blood volume (MBV) occurred only in YOUNG and these effects were isolated to the early postprandial phase (+45% at ∼45 min after feeding) coinciding with detectable arterio-venous differences in EAA reflecting net uptake by muscle. Increases in microvascular flow velocity (MFV) and tissue perfusion (MBV × MFV) occurred (∼2 h) in YOUNG and OLD-ARG, but not OLD. Postprandial protein accretion was greater in YOUNG than OLD or OLD-ARG; the latter two groups being indistinguishable. Therefore, ARG rescues aspects of muscle perfusion in OLD without impacting anabolic blunting, perhaps due to the “rescue” being beyond the period of active EAA-uptake

    Correlation between visual acuity, external limiting membrane and photoreceptor status in patients with neovascular age-related macular degeneration treated with bevacizumab

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    © 2017, Institut za Vojnomedicinske Naucne Informacije/Documentaciju. All rights reserved. Background/Aim. The integrity of outer retinal structures, primarily the photoreceptor layer, is important because of its direct correlation with visual acuity. The aim of this study was to investigate the correlation between best-corrected visual acuity (BCVA), the foveal photoreceptor-inner seg-ment/outer segment (IS/OS) junction and external limiting membrane (ELM) in patients with neovascular age-related macular degeneration (NVAMD) after the treatment with bevacizumab, as well as the correlation between the above-mentioned parameters and different types of neovascular membrane, classified by fluorescein angiography (FA). Me-thods. The study included 82 patients with NVAMD, treated with intravitreal bevacizumab. All patients under-went a basic ophthalmological examination, FA and optical coherence tomography (OCT). Based on the results of FA, all the patients were divided into two main groups - type I (the occult and minimally classic) and type II (classic and predominantly classic) of the choroidal neovascular mem-brane (CNV). The OCT images revealed either the presence or the absence of IS/OS and ELM. Results. After the treatment, the mean best corrected visual acuity improved significantly in both groups (p 0.05). Conclu-sion. The patients with preserved IS/OS and ELM achieved better final visual acuity as compared to the pa-tients without preserved IS/OS and ELM. In our patients, the absence of IS/OS and ELM were more frequent in type II (classic and predominantly classic) CNV than in type I (the occult and minimally classic) CNV

    Molecular aberrations of the G1-S checkpoint in myxoid and round cell liposarcoma.

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    Myxoid and round cell liposarcoma represents a morphological spectrum in which tumor progression from low-grade myxoid to high-grade round cell areas is frequently observed. A distinctive t(12;16)(q13;p11) reciprocal translocation rearranges the CHOP gene localized to 12q13 in most cases. Data concerning the occurrence of cell cycle aberrations in this subset of mesenchymal malignancies are very limited. Therefore, we analyzed a histologically homogeneous series of 21 cases of myxoid and round cell liposarcoma. The p53 pathway was studied by investigating the TP53 gene and protein, mdm2 protein, and p21Waf1 protein. The Rb-cyclin D pathway was analyzed by studying the pRb protein, the p16MTS1 gene, cyclin D1, cyclin D3, p27Kip1, cdk4, and cdk6 proteins. In contrast with the rare involvement of the TP53 gene in well differentiated liposarcoma, aberrations of the TP53 gene were observed in approximately 30% of cases of myxoid and round cell liposarcoma. Notably, mdm2 overexpression was seen in 56% of cases and correlated with histological grade, therefore indicating a possible role in tumor progression. Abnormalities involving the Rb-cyclin D pathway were observed in more than 90% of cases. pRb loss was present in one-third of cases and, at variance with that observed in other subsets of sarcoma, overexpression of cyclin Ds represented a rare event. Interestingly, upregulation of either cdk4 or cdk6 was demonstrated in 85% of cases

    The MLL partial tandem duplication: evidence for recessive gain-of-function in acute myeloid leukemia identifies a novel patient subgroup for molecular-targeted therapy

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    MLL (ALL-1) chimeric fusions and MLL partial tandem duplications (PTD) may have mechanistically distinct contributions to leukemogenesis. Acute myeloid leukemia (AML) blasts with the t(9;11)(p22; q23) express MLL-AF9 and MLL wild-type (WT) transcripts, while normal karyotype AML blasts with the MLLPTD/WT genotype express MLL PTD but not the MLL WT. Silencing of MLL WT in MLLPTD/WT blasts was reversed by DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors, and MLL WT induction was associated with selective sensitivity to cell death. Reduction of MLL PTD expression induced MLL WT and reduced blast colony-forming units, supporting opposing functions for MLL PTD and MLL WT whereby the MLL PTD contributes to the leukemic phenotype via a recessive gain-of-function. The coincident suppression of the MLL WT allele with the expression of the MLL PTD allele, along with the functional data presented here, supports the hypothesis that loss of WT MLL function via monoallelic repression contributes to the leukemic phenotype by the remaining mutant allele. These data from primary AML and the pharmacologic reversal of MLL WT silencing associated with a favorable alteration in the threshold for apoptosis suggest that these patients with poor prognosis may benefit from demethylating or histone deacetylase inhibitor therapy, or both
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