Development of Fourier-transformed mid-infrared spectroscopy prediction models for major constituents of fractions of delactosated,defatted milk obtained through ultra- and nanofiltration

Milk filtration procedures are gaining relevance in the dairy industry because milk ultra- and nanofiltrates are used to increase milk processing efficiency, and as additives for products with improved nutraceutical properties. This study aimed to develop Fourier-transformed mid-infrared spectroscopy calibrations for ultra- and nanopermeate and retentate fractions of defatted and delactosated milk. A total of 154 samples from different milk fractions were collected and analyzed using reference methods to determine protein, solids-not-fat, glucose, and galactose content. The obtained values were matched with their respective Fourier-transformed mid-infrared spectroscopy spectra to develop new prediction models. Calibrations for each trait were built following 3 different approaches to get the best prediction models: (1) using the entire data set, (2) using 3 subsets based on component concentrations (level approach), and (3) using hierarchical clusters calculated with pairwise Mahalanobis distance among spectra (cluster approach). Calibrations were developed using partial least squares regression, after removing low signal-to-noise ratio wavelengths, and validated through a leave-one-out cross-validation procedure. In addition, the accuracy of the predicted values within each fraction was checked for each approach. Dividing the data set into subsets improved prediction models for each trait and for the samples in each milk fraction. Without considering milk fraction, the best improvement was observed for glucose and galactose. Glucose ratio performance deviation in cross-validation (RPD) increased from 7.42 to 11.31 and 11.06, for cluster and level approaches, respectively, whereas galactose RPD increased from 8.86 to 11.69 and 11.27 for cluster and level approaches, respectively. Considering milk fractions, the best improvement was observed for protein content, where RPD ranged from 0.08 to 6.06 for the whole data set calibration, whereas it ranged from 0.43 to 40.34 for the subset calibration approaches. Cluster and level approaches to build calibration models were comparable for samples from different fractions, suggesting that the 2 subsetting protocols should be both investigated to get the best prediction performances.     

Mitochondrial Malfunctioning,Proteasome Arrest and Apoptosis in Cancer Cells by Focused Intracellular Generation of Oxygen Radicals

Photofrin/photodynamic therapy (PDT) at sub-lethal doses induced a transient stall in proteasome activity in surviving A549 (p53^+/+) and H1299 (p53^−/−) cells as indicated by the time-dependent decline/recovery of chymotrypsin-like activity. Indeed, within 3 h of incubation, Photofrin invaded the cytoplasm and localized preferentially within the mitochondria. Its light activation determined a decrease in mitochondrial membrane potential and a reversible arrest in proteasomal activity. A similar result is obtained by treating cells with Antimycin and Rotenone, indicating, as a common denominator of this effect, the ATP decrease. Both inhibitors, however, were more toxic to cells as the recovery of proteasomal activity was incomplete. We evaluated whether combining PDT (which is a treatment for killing tumor cells, per se, and inducing proteasome arrest in the surviving ones) with Bortezomib doses capable of sustaining the stall would protract the arrest with sufficient time to induce apoptosis in remaining cells. The evaluation of the mitochondrial membrane depolarization, residual proteasome and mitochondrial enzymatic activities, colony-forming capabilities, and changes in protein expression profiles in A549 and H1299 cells under a combined therapeutic regimen gave results consistent with our hypothesis.     

HE4 in the Differential Diagnosis of a Pelvic Mass: A Case Report

Neoplasms of the ovary present an increasing challenge to the physician. Neoplastic ovarian cysts can resemble endometriomas in ultrasound imaging and need to be carefully considered in the differential diagnosis. We report the case of a woman with a strong family history of hereditary breast and ovarian cancer, who presented with a pelvic mass. The young girl refused oncogenetic counseling and genetic testing, even though she had a 50% a priori probability of being a BRCA1 mutation carrier. Pelvic magnetic resonance imaging (MRI) and a comparative analysis of the serum concentration of HE-4 and CA125 biomarkers provided accuracy and sensitivity in the diagnosis of a benign ovarian pathology. Based on this experience, we propose that the sensitivity of a screening program based on a HE4 and CA125 assay and MRI in high risk patients with mutations in the BRCA1 and BRCA2 genes may be considered a useful pre-operative tool for the differential diagnosis of pelvic masses.     

Up‐cycling end‐of‐use materials: Highly filled thermoplastic composites obtained by loading waste carbon fiber composite into fluidified recycled polystyrene

Carbon fibers reinforced epoxy resins are used in a wide range of applications, such as automotive and aerospace industry. Because of their thermosetting nature, recycling at the end of the life cycle is a difficult issue. However, lack of recyclability poses environmental concerns to the use of these composite materials. In this article, a sustainable, cost‐effective technological approach aiming at recycling postconsumer carbon fibers reinforced thermosets (CFRT) is proposed. Composites containing 50 and 70 wt% of CFRT particles were prepared by incorporating the filler fraction into a fluidified postconsumer expanded polystyrene matrix. A cold mixing approach consisting in the use of a low boiling solvent as a binder to guarantee the dispersion homogeneity on micro‐ and macroscopic level was set up. For comparison, analog composites were also prepared through melt mixing process. Morphological, mechanical, and thermal analyses allowed to prove the effectiveness of the cold mixing approach and to evaluate the influence of particle size on the performance of new recycled composites. Thermogravimetric analysis and thermal conductivity tests of samples highlighted further peculiarities of the cold mixing process. The approach proposed is an effective recycling technology for CFRT and could be extended to other postconsumer materials. POLYM. COMPOS., 35:1621–1628, 2014. © 2013 Society of Plastics Engineers     

Adsorptive properties of sol–gel derived hybrid organic/inorganic coatings

Hybrid organic-inorganic sol–gel derived coatings have been prepared by dip coating on glass substrates from alcoholic solutions of tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), 3-aminopropyltriethoxysilane (APTES), 3-glycidoxypropyltrimethoxysilane (GPTMS) and phenyltriethoxysilane (PhTES). The hybrid materials have been fully characterized by means of solid state NMR spectroscopy and X-ray diffraction. The degree of cross-linking and the extent of interaction between silica and silsesquioxane phases appear dependent on the ratio between TEOS and organotrialkoxysilane and on the chemical features of the organic function linked to silicon, and influence the sorption ability towards aromatic compounds of hybrid films. The hybrid coatings have been put into an optical-grade quartz chamber placed into a UV–VIS–NIR spectrophotometer and the organic compounds have been allowed flowing through the chamber recording of molecule absorption spectra vs. time. Absorbance curves vs. time have also been collected at a fixed wavelength for different molecule-coating couples and simple kinetic models have been used for comparing the adsorption capability of the different films, which has been related to the chemical interactions between molecules and coatings.     

Chemical vapor generation of arsane in the presence of L-cysteine. Mechanistic studies and their analytical feedback

The complex reactivity of the system As-AH-RSH-THB (As=As(III), As(V); AH=HCl, HClO4, CH3COOH; RSH=L-cysteine (Cys); THB=NaBH4) was investigated using continuous flow (CF) hydride generation (HG) coupled either with atomic absorption (AAS) or atomic fluorescence spectrometry (AFS). AsH3 generation was examined in the presence of Cys by varying acidity and the type of acid, the mixing sequence, and the reaction time of reagents. The strong depression of arsane generation, which is typically observed in the range of acidity of 0.2-2 M HCl, can be addressed to the low reaction rate of thiol-borane, hydroboron complexes, or both toward those As(III) substrates that are formed in the same reaction environment. The simultaneous presence of Cys-borane and As(III)-Cys species is at the origin of the gap of the arsane generation efficiency in the 0.2-2 M HCl acidity range. The selective formation of Cys-borane complexes, which are formed faster than As(III)-thiol complexes, can be achieved by a careful choice of the mixing sequence of the reagents. The simultaneous mixing of sample, Cys, and THB is able to reduce substantially the gap of the arsane generation efficiency in the 0.2-2 M HCl acidity range. These properties were employed to implement a simple method for selective determination of As(III) in samples containing inorganic arsenic: (i) Total inorganic arsenic is determined by sample treatment with 0.2 M Cys for 30 min, acidity 0.1 M HCl, followed by CF-HG-AFS; (ii) As(III) is selectively determined in 0.005 M CH3COOH in the presence of Cys using a chemifold setup allowing the simultaneous mixing of sample, 0.2 M Cys and 0.1 M THB. The selectivity, measured from the ratio between the slopes of calibration graphs As(III)/As(V), is 220. The interference effects of Cu(II), Fe(III), Ni(II), Co(II), Ag(I), Pd(II), and Pt(IV) can be kept under control using the simultaneous mixing of all the reagents. The tolerance toward the interferences was almost the same as that obtained by allowing the formation of As(III)-Cys complexes (offline sample pretreatment with Cys for 30 min). The method was tested with the application to the natural waters and mineral well waters analysis employing CF-HG-AFS.     

The Effect of a Silver Nanoparticle Polysaccharide System on Streptococcal and Saliva-Derived Biofilms

In this work, we studied the antimicrobial properties of a nanocomposite system based on a lactose-substituted chitosan and silver nanoparticles: Chitlac-nAg. Twofold serial dilutions of the colloidal Chitlac-nAg solution were both tested on Streptococcus mitis, Streptococcus mutans, and Streptococcus oralis planktonic phase and biofilm growth mode as well as on saliva samples. The minimum inhibitory and bactericidal concentrations of Chitlac-nAg were evaluated together with its effect on sessile cell viability, as well as both on biofilm formation and on preformed biofilm. In respect to the planktonic bacteria, Chitlac-nAg showed an inhibitory/bactericidal effect against all streptococcal strains at 0.1% (v/v), except for S. mitis ATCC 6249 that was inhibited at one step less. On preformed biofilm, Chitlac-nAg at a value of 0.2%, was able to inhibit the bacterial growth on the supernatant phase as well as on the mature biofilm. For S. mitis ATCC 6249, the biofilm inhibitory concentration of Chitlac-nAg was 0.1%. At sub-inhibitory concentrations, the Streptococcal strains adhesion capability on a polystyrene surface showed a general reduction following a concentration-dependent-way; a similar effect was obtained for the metabolic biofilm activity. From these results, Chitlac-nAg seems to be a promising antibacterial and antibiofilm agent able to hinder plaque formation.     

Light-emitting nanocomposite CdS-polymer electrospun fibres via in situ nanoparticle generation

We report on the simple, in situ generation of CdS nanocrystals inside electrospun polymer fibres by thermal decomposition of a cadmium thiolate precursor, leading to nanocomposite light-emitting fibres. The modifications induced in the precursor by the thermal decomposition are investigated by a morphological, structural and spectroscopic analysis of the resulting nanocomposite fibres. This approach allows us to overcome nanofabrication difficulties related to disfavoured micro- or nanofluidic molecular flow as given by the direct incorporation of particles in the electrospinning solution. This method therefore enables the synthesis of luminescent, CdS-based composite fibres with emission peaked in the visible range, suitable as building blocks for nanophotonic devices based on light-emitting nanomaterials.     

Gelation kinetics of crosslinked gelatin

Experimental results have shown that the kinetics of bond formation in chemical crosslinking of gelatin solutions is strongly affected not only by gelatin and reactant concentrations but also by the solution pH. We present an extended numerical investigation of the phase diagram and of the kinetics of bond formation as a function of the pH, via Monte Carlo simulations of a lattice model for gelatin chains and reactant agent in solution. We find that gelation can be hindered either by loop formation, at low reactant concentrations, or by saturation of active sites of the chains via formation of single bonds with crosslinkers, at high reactant concentrations. The ratio of the characteristic times for the formation of first and the second bond between the crosslinker and an active site of a chain is found to depend on the reactant reactivity, in good agreement with experimental data. POLYM. COMPOS., 2013 © 2013 Society of Plastics Engineers