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• Automatic defect detection in glass composites using terahertz radiation. • Time-domain spectroscopy reflective scanner with an electronically controlled optical sampling scheme. • Pre-selection of C-scans with defect-related features. • Thresholding method based on Gaussian histogram fitting. • Size and depth of inclusions and delaminations determined with high accuracy. We developed a method for automatic detection of defects in glass fibre reinforced polymer (GFRP) based on a terahertz time-domain spectroscopy (TDS) system. Two GFRP specimens with round defects of different sizes (inclusions and delaminations) were measured by means of a high-speed TDS reflective scanner with an electronically controlled optical sampling scheme. The algorithm provided a series of C-scans, which were then pre-selected to identify only those with features potentially associated with defects. A thresholding method based on Gaussian fitting of the histogram was developed. The results showed that 87 % of defects were detected for the specimen with inclusions and 100 % for the specimen with delaminations. The algorithm also provided information about the depth of defects, as each C-scan was assigned to a time slice. The results demonstrate that the TDS-based system, along with the proposed histogram-based method, can automatically detect defects in GFRP. © 2017 Elsevier Inc. All rights reserved. [ABSTRACT FROM AUTHOR]

• Artillery combustible cartridge case scanned with terahertz radiation. • THz rotary scanner with time domain spectroscopy in reflection configuration. • Wire polariser employed as a reference for stable time difference determination. • Case radius measured with an uncertainty of 0.04 mm. • Thickness of the case wall determined with an uncertainty of 0.03 mm. In this study, terahertz radiation was employed to determine the radius, diameter, and thickness of the nitrocellulose combustible cartridge case used for tank ammunition. The construction of the sample was outlined, and the refractive index of the case material was measured. A terahertz rotary scanner with a time-domain spectroscopy setup in reflection configuration was developed, and its performance and parameters were determined. A wire polariser was introduced as a reference to determine the stable time difference. The radius and diameter measurements of the case were based on a reference terahertz pulse reflected from its metal base. The thickness of the case was calculated based on the time difference between pulses reflected from its inner and outer surfaces. These measurements were in agreement with the reference measurements. The results prove that the developed setup and measurement methods are suitable for the non-destructive evaluation of cases and provided satisfactory performance. [ABSTRACT FROM AUTHOR]

The nanoemulsion-based delivery systems have gained particular attention due to effective encapsulation and protection of hydrophobic active compounds. However, several features like limited stability, cellular uptake or release of payloads still need to be addressed. We investigated the uptake of the nanocapsules based on the amphiphilic derivative of hyaluronate with oleic acid cores (oil-in-water nanoemulsion) and their anticancer activity in vitro. The core-shell nanocapsules exhibiting long term stability in dispersion showed an enhanced uptake by cancer cells and effectively killed them only if composed of hyaluronate-based shells and oleic acid cores - the anionic chitosan-based shells and/or corn oil cores were used for control experiments. We concluded that the nanocapsules stabilized by the amphiphilic derivative of hyaluronic acid may serve as very stable and efficient delivery systems for oil-soluble compounds without necessity of application of low molecular weight (co)surfactants. The in vitro studies indicated anticancer activity of such delivered oleic acid and crucial role of hyaluronate shell of the nanocapsules in its efficient delivery and enzyme-triggered disintegration inside cells. Corn oil was shown as a nutrient that can serve as an inert vehicle in the studied nanoemulsion that exhibit application potential in food, dietary supplement industry and medicine. Unlabelled Image • Nanocapsules with hyaluronate-based shell and oil core are efficiently uptake intracellularly. • Oleic acid in hyaluronate-based nanocapsules shows superior anticancer activity in vitro. • Cellular hyaluronidases degrade the capsules shell releasing their oil cores. [ABSTRACT FROM AUTHOR]

The lack of the N-alpha-glucosaminidase (Naglu) is responsible for the incidence of a rare disease - mucopolysaccharidosis, type IIIB (MPS IIIB). To date, studies have been conducted based on cells derived from patients suffering from MPS or using in vivo MPS mouse models. These limitations have allowed for defining our research goal - to create and characterize the first in vitro murine cellular MPS IIIB model. In the current work we present a new, stable cell line with confirmed accumulation of glycosaminoglycans. The line stability was achieved by immortalization using a lentivirus carrying the T-antigens of SV40. The Naglu −/− cells were confirmed to produce no Naglu enzyme. To confirm the proper functioning of the in vitro MPS IIIB model, we determined the activity and expression of cystathionine γ-lyase, rhodanese and 3-mercaptopyruvate sulfurtransferase, as well as the level of low molecular-weight thiols (reduced and oxidized glutathione, cysteine and cystine). The results were referred to our earlier findings originating from the studies on the tissues of the Naglu −/− mice that were used to create the lines. The results obtained in the Naglu −/− cells were in accordance with the results found in the mouse model of MPS IIIB. It suggests that the presented murine Naglu −/− cell lines might be a convenient in vitro model of MPS IIIB. • The Naglu −/− cell lines may be an in vitro model of mucopolysaccharidosis type IIIB. • The cysteine level is elevated in the Naglu −/− cells. • The Naglu −/− cells have a weak antioxidant potential. • endo- and exogenous heparan sulfate demonstrate different biological activity. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract A cationic derivative of γ-cyclodextrin (GCD) modified with propylenediamine (PDA) was synthesized. It was shown that the derivative (GCD–PDA) is mucoadhesive and resistant to the digestion with ∝-amylase indicating that it may constitute an efficient oral delivery vehicle. GCD-PDA formed an inclusion complex with berberine (BBR), an alkaloid displaying a multitude of beneficial physiological effects. The complexed BBR penetrates a lipid membrane easier than the free one. Both uncomplexed BBR and that complexed with GCD-PDA was delivered to normal (NMuMG) and cancerous (4T1) murine mammary gland cells. In the normal cells both free and complexed BBR was homogeneously dispersed in the cytoplasm and was nontoxic up to 131 μM. In the cancerous cells uncomplexed BBR was also homogeneously dispersed but it was toxic to about 25% of cells at 131 μM, while the GCD-PDA/BBR complex was preferably localized in lysosomes and its toxicity doubled at this concentration compared to that of free BBR. Moreover, free BBR and GCD-PDA/BBR showed even more efficient inhibitory effect against murine melanoma (B16-F10) cells than against 4T1 cells. [ABSTRACT FROM AUTHOR]

Abstract Lactobacillus rhamnosus GG is an environmentally and human-friendly bacteria that can be found in probiotics. However, it is incapable of forming a biofilm on metal surfaces, what limits the possibility of using it in bioelectrochemical systems (BESs) as promising and green alternatives. Hence, we propose a simple and cost-effective modification of metal surface with cationic dextran derivative (DEX-G) by using the electrostatically driven self-assembly procedure resulting in the formation of a polymeric monolayer. Modification of metal electrodes was confirmed by using infrared spectroscopy (IR) and atomic force microscopy (AFM). Synthesized metal/polycation electrodes provided a bioactive environment for L. rhamnosus GG enhancing its proliferation and formation of the biofilm as confirmed by SEM imaging. Moreover, using cyclic voltammetry (CV) and chronoamperometry measurements, it was proven that metal/polycation/ L. rhamnosus bioelectrodes are electrochemically active in the glucose-rich medium. The electrochemical activity of fabricated bioanodes allows to consider them for their potential use in the bioelectrochemical systems. Graphical abstract Image 1 Highlights • Metal surface modification method facilitating the biofilm formation is proposed. • Use of lactic acid bacteria for bioelectrochemical systems is examined. • Cationic dextran coating enhanced bacteria colonization of gold. • The electroactivity of proposed bioanodes was confirmed by cyclic voltammetry. [ABSTRACT FROM AUTHOR]

Abstract: A tunable temperature-responsive nanoparticulate system based on the ionic modifications of hydroxypropyl cellulose (HPC) was obtained. Two derivatives of HPC were successfully obtained and characterized: cationic (modified with trimethylammonium groups) and anionic (modified with styrenesulfonate groups). Due to the polycation-polyanion interactions they spontaneously self-assemble into nanoparticles in water. The size and surface charge of the nanoparticles can be controlled by the polycation/polyanion ratio. The resulting structures are spherical with diameters in the range from 150 to 250nm, as confirmed by AFM, SEM, and DLS measurements. The size of the nanospheres increases in elevated temperatures. A model compound, curcumin, known for its anti-cancer and anti-inflammatory properties, was effectively entrapped inside nanospheres. Its release profile was found to be temperature-dependent. [Copyright &y& Elsevier]

In this paper, the molecular dynamics as well as inter- and intramolecular interactions in the homogenous solid dispersions (SDs) of active pharmaceutical ingredient - probucol (PRO) with acetylated glucose (acGLU), acetylated sucrose (acSUC), and sucrose acetoisobutyrate (aibSUC), prepared in 5:1 molar ratio, have been investigated using broadband dielectric (BD) and Fourier transform infrared (FTIR) spectroscopy. Importantly, high pressure dielectric measurements revealed that as for neat PRO, a breakdown of the isochronal structural (α) and JG- β exact superpositioning, due to increasing separation between both processes under compression, can also be detected in its mixtures with acetylated saccharides (acSACCHs). Furthermore, the analysis of temperature dependences of JG- β -relaxation times for PRO and PRO-acSACCH SDs at selected isobaric conditions indicated the increase in the cooperativity of the secondary process (reflected in the value of the activation entropy, Δ S β) at elevated pressure in all systems. The mere addition of the small amount of excipient to neat PRO (p = 0.1 MPa) resulted in a greater value of Δ S β (it was the most noticeable in the case of aibSUC). Further FTIR studies carried out on the pressure densified glasses of PRO, and binary mixtures suggested that the observed changes in the cooperativity of the JG- β -process, as well as the failure of the exact isochronal superpositioning of α - and JG- β relaxation times, are due to varying H-bond pattern in the examined single- and two-component systems at high compression/in the presence of saccharide. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, we studied for the first time the impact of the molecular weight, M n , and the topology on the molecular dynamics of a series of grafted poly(poly(dimethylsiloxane methacrylate)) (polyPDMSMA). The behavior of grafted (molecular brushes) polyPDMSMA and their three-armed counterparts of tailor-made properties prepared by Atom Transfer Radical Polymerization (ATRP) was monitored by means of broadband dielectric spectroscopy (BDS), differential scanning calorimetry (DSC) and comprehensive rheology analysis. Surprisingly, the dielectric loss spectra of all studied polyPDMSMA exhibit the presence of two dielectric relaxation processes above their glass transition temperature, T g. A comparison of dielectric, calorimetric and mechanical data indicated that the faster and slower relaxation processes identified in loss spectra can be related to the segmental and chain dynamics, respectively. Interestingly, we observed that the "local" segmental dynamics of studied polyPDMSMA, involving the mobility of few repeatable units creating a segment, is almost unaffected by neither the length of polymer chain, number of grafts nor its topology. This is also reflected in a weak molecular weight-dependences of T g of studied polyPDMSMA independently to their topology. On the other hand, the time-scale separation between segmental and the chain modes as well as the amplitude of the latter process increase with growing M n of all examined polyPDMSMA. Additionally, it should be mentioned that the mechanical data collected for samples characterized by high molecular weight (of M n > 280 kg/mol) reveal the emergence of additional process (most likely related to the grafts and/or the star arm relaxation) at the intermediate regime, independently to their topology. Interestingly, this mode was observed to be much slower for the star-shaped macromolecules when compared to the grafted polymers, despite their lower M n. This implies that the observed differences are not a result of different molecular weights, but rather originate from a various molecular mechanism due to the different topology of the studied samples. In this context, one can assume that in the case of high-molecular-weight macromolecules, the backbone architecture has a significant influence on the behavior of polymers, including their molecular dynamics. [Display omitted] • Increase of the glass transition of studied polyPDMSMA with their molecular weight. • Loss spectra of polyPDMSMA exhibit multiple dielectric relaxation processes. • Observed dielectric processes were assigned as the chain and segmental modes. • Presence of grafts/arms relaxation (or entanglement segments) in mechanical data. [ABSTRACT FROM AUTHOR]

Different experimental techniques were applied to study thermal and structural properties, strength of H-bonds, possible keto - enol tautomerism and molecular dynamics at various thermodynamic conditions in the H-bonded active substance, curcumin (CRM). Dielectric measurements revealed dynamical features of examined compound that are uncharacteristic for the associated systems. This includes enormously large pressure coefficient of the glass transition temperature and prominent drop of the fragility with compression. Simultaneously, the shape of α -process slightly broadened at elevated pressures. Infrared investigations demonstrated that this effect is related to the variation in the population of H-bonds. Moreover, we studied the changes in the structural and dynamical properties of the glasses prepared upon cooling of the melt (ordinary glass, OG) and the one obtained after compression of CRM in the liquid phase and decompression at T = 293 K (dense glass, DG). Interestingly, during the aging of the latter sample, a clear shift of the β -relaxation towards higher frequencies was noted. This unexpected result indicated that the density of DG is probably getting smaller with time. Complementary X-ray diffraction experiments confirmed this supposition. Additionally, they showed that in DG there are traces of polymorph II of CRM that has a higher density than initial crystals (polymorph I). Finally, infrared studies demonstrated that H-bond pattern in DG is slightly different with respect to OG. Furthermore, Raman investigations suggested that probably keto - enol tautomerism might be shifted towards diketo form in the glass obtained at high compression. Our investigations are very interesting in the context of better understanding of the behavior of associated systems at high compression as well as provide a better insight into dynamics of higher density glasses produced at elevated pressures. Unlabelled Image [ABSTRACT FROM AUTHOR]

In this paper, the high-pressure calorimetry was used to monitor the heat of the polymerization of bisphenol-A diglycidyl ether (DGEBA) mixed with a stoichiometric amount of aniline over a wide range of pressure (p = 0.1–350 MPa at T = 298.15 K). To the best of our knowledge, this is the first high-pressure calorimetric study of the reaction kinetics of the epoxy resin curing processes. The collected novel experimental data were analysed with two models: the original Kamal and its modified version taking into account the real monomer conversion, which provides insight into the progress of two subsequent non-catalyzed and catalyzed reactions occurring during the step growth polymerization. It was found that the determined rate constants are sensitive to pressure and model dependent, resulting in different activation volumes, which fall within the range from −16 cm3/mol to −26 cm3/mol. Interestingly, these values are similar to those reported for the epoxide ring-opening polymerization reaction, which changes in the range between −15 cm3/mol to −20 cm3/mol. In addition, the analysis of the high-pressure data revealed that the original Kamal model fails to describe kinetic curves obtained for the polymerization reaction, where the monomer conversion is far below 100%. Interestingly, such effects are considered to be due to the change in the mechanism of the reaction from mass to the diffusion-controlled regime. Here, we explicitly have shown that it has nothing to do with this phenomenon since after considering solely the real monomer conversion in the Kamal model fits, quality has been significantly improved. As a consequence, estimated rate constants are more reliable. Results presented herein clearly indicated that high-pressure experiments provide a new perspective to understand the progress of the classical reactions, as step-growth polymerization that has mainly been studied as a function of the chemical composition and temperature. Image 1 - High-pressure calorimetric data for step-growth polymerization (SGP) are presented - Original Kamal and modified version considering the monomer conversion were tested - Original model fails if the real monomer conversion is far below 100% - Rate constants are sensitive to pressure and model dependent - Activation volumes of catalyzed and non-catalyzed reactions in SGP are different [ABSTRACT FROM AUTHOR]

Highlights • There are marked differences in dynamics of modified linear and cyclic carbohydrates. • A variation in the distribution of τ α between linear and cyclic compounds is observed. • The evolutions of the T g and m versus M w in both groups of materials are different. • The shape of the α -process in saccharides of the same topology doesn't change with M w. Abstract In this paper, the molecular dynamics and thermal properties of representative acetylated linear and cyclic oligosaccharides: acTRE, acRAF, acSTA, ac-α-CD, ac-β-CD, ac-γ-CD, have been investigated by using broadband dielectric spectroscopy and differential scanning calorimetry. We found that there are marked differences in the dynamics of the structural and secondary relaxation processes in both groups of materials. Just to mention a variation in the distribution of the structural relaxation times as well as different evolutions of the glass transition temperature (T g) and fragility (m) versus molecular weight (M w), which seem to be affected by the shape of the molecule, strain in the carbohydrate ring and mobility of side acetyl moieties. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated dielectric response at ambient and elevated pressure of poly(mercaptopropyl)methylsiloxane (PMMS) based oligomeric brushes, where the thiol moiety was substituted by various butyl acrylate isomers (n -butyl acrylate (nBA), iso -butyl acrylate (isoBA), tert -butyl acrylate (tertBA)). It was found that the glass transition temperature, T g , of PMMS is much lower with respect to the other systems despite its ability to form weak hydrogen (H) bonds. What is more, the length scale of cooperativity was the highest in homopolymer and scaled with the steric hindrance of the graft. We also demonstrated that in the examined grafted copolymers, there is one broad relaxation process in dielectric spectra which is wider than that recorded in mechanical response. That probably means that similarly to PMMS, there are two relaxation processes above T g in grafted copolymers. However, due to similar timescale, they cannot be separated. Further, high-pressure experiments revealed that pressure coefficient of the glass transition temperature, d T g / d p , as well as the activation volume, Δ V , calculated for the segmental process surprisingly does not scale with either the size of monomer nor steric hindrance. This unexpected result must be related to the specific structure adopted by the studied grafted oligomers. Presented herein data expand our understanding on the impact of topology on the dynamics of polymers at ambient and high pressure. [Display omitted] • The glass transition temperature is strongly affected by a graft structure. • All grafted materials revealed the broad segmental relaxation process. • The shape of the α -process remains constant with pressure for all materials. • The pressure coefficient of the glass transition changes with graft structures. [ABSTRACT FROM AUTHOR]

A new method for fabrication of chitosan-based hydrogel implants intended for peripheral nervous tissue regeneration was developed. The method is based on an electrodeposition phenomenon from a solution of chitosan and organic acid. In order to increase the mechanical strength of the implant, the solution was enriched with hydroxyapatite. Hydroxyapatite served as a source of calcium ions too. The influence of the concentration of the polymer and the additive on chemical, mechanical as well as biological properties of the obtained implant was evaluated. The study showed great dependence of the initial solution composition mainly on the physicochemical properties of the resulting structure. Basic in vitro cytotoxic and pro-inflammatory assays showed biocompatibility of manufactured implants, therefore, animal experimentations may be considered. [ABSTRACT FROM AUTHOR]

This work demonstrates the effect of a high dc bias field (up to 160 kV/cm) on the polyaddition reaction of the modeled epoxy resin system. Polymerization of bisphenol A diglycidyl ether (DGEBA) supported by high electric field results in obtaining epoxides with significantly increased molecular weight, which is seven-fold higher than the zero-field reference (M n = 4.7 kg/mol). We also found a markedly reduced dispersity (Ð = 1.52 at 0 kV/cm, Đ = 1.21 at 160 kV/cm). The molecular weight and dispersity of obtained polymers change almost linearly with the reaction time. By following polymerization kinetics in the real-time of the experiment, via dielectric spectroscopy, we observe slowing down the reaction progress at dc fields of E = 160 kV/cm, compared to the zero-field case, E = 0 kV/cm. The polymer materials obtained in the presence/absence of static electric fields exhibit distinctly different glass transition temperatures. Our study highlights a better control over the reaction and product properties attained by using only the magnitude of the applied field as the control variable. Thus, a high electric field could provide an alternative pathway in synthesizing and developing advanced polymer materials using simpler, "green", less-expensive, and technologically demanding approaches. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, we report 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) supported high-pressure approach enforcing Ring-Opening Polymerization (ROP) of γ-butyrolactone (GBL), that due to unfavorable thermodynamics and low ring strain, is considered as a hardly polymerizable monomer. Application of Broadband Dielectric Spectroscopy (BDS) allowed us to find optimal thermodynamic conditions to perform well-controlled and notably fast polymerization (even within 1 h!), avoiding undesired crystallization process. It was shown that by varying pressure and temperature conditions, we could control molecular weight, dispersity of recovered macromolecules, as well as rate and efficiency of the reaction that are significantly altered with respect to the reference process carried out at ambient conditions. Experiments performed at respectively very low temperature T = 233 K and low/moderate pressure (p = 75–250 MPa) and much higher temperatures (T = 248–268 K) and compressions (p = 1000 MPa) yielded poly(γ-butyrolactone) (PGBL) of tailored absolute molecular weight in moderate range M n = 2.8–15.0 (up to 30.3) kg/mol and narrow/moderate dispersity ranging from Đ = 1.12–1.89. What is more, the implementation of MALDI-TOF, GPC and DSC analyses, clearly indicated that as i) the time of reaction gets longer, ii) the amount of catalyst increases, iii) the temperature lowers, the content of cyclic products in produced polymers grows. This phenomenon influences the rheological properties (viscosity), foil formation ability (films) and cell culture proliferation features of the recovered macromolecules. Presented results open a highly effective and repeatable route to produce PGBL via pressure-assisted ROP and indicate the possibility of tuning properties of this polymer by varying concentration of cycles or eventual block copolymerization with other biorelevant monomers to meet the expectations of the biotechnological industry. [Display omitted] • Organocatalyzed high-pressure assisted γ-butyrolactone Ring-Opening Polymerization. • Well-defined macromolecules (M n up to 30.3 kg/mol; low to moderate Đ = 1.12–1.89). • External catalytic effect of high pressure: reduced reaction time; increased yield. • Monitoring the polymerization progress in situ using BDS technique. • Analysis: NMR, GPC, MALDI, DSC, SEM, rheology, cytotoxicity, cell proliferation. [ABSTRACT FROM AUTHOR]