High Molecular Weight Components Research Articles

Investigation of the optical, mechanical, and radiation shielding features for strontium-borotellurite glass system: Fabrication, characterization, and EPICS2017 computations

The optical, mechanical and radiation shielding features of novel (60-x) TeO2-10SrO-(30+x)B2O3 glass systems have been investigated. The density of the glasses decreases from 5.107 to 3.593 g/cm3 whereas the molar volume increases from 24.86 to 30.32 cm3 as the concentration of the TeO2 decreases. The band gap energy increases from 3.388 to 3.417 eV and from 3.083 to 3.118 eV for direct and indirect bandgap, respectively with the decreasing concentration of the TeO2. Further, the Urbach energy descends from 0.03959 to 0.03306 with an ascending insertion of the TeO2. The increase in elastic moduli indicated the improvement in the elastic properties of the samples with increase in TeO2 concentration. The mass attenuation coefficient (μ/ρ) was calculated via EPICS2017, and the results revealed that the μ/ρEPICS2017 is slightly lower than μ/ρ XCOM by an average of 0.001 cm2 g−1 for the five glasses, and this means that the two theoretical models of the five glass samples are in good agreement. The linear attenuation coefficient (µ) was calculated and we found that when the concentration of the high molecular weight component (TeO2) decreases from 60 to 40 mol%, a reduction in the µ is occurred, and the µ follows the trend: TBS30 > TBS35 > TBS40 > TBS45 > TBS50. We also determined the average half value layer (HVL̅) for each glass sample and we found that the HVL̅ varied between 1.835 cm (for TBS30) and 2.614 cm (for TBS50). An inverse relation between the TeO2 content and the HVL̅ is reported.

The Influence of Ethyl Branch on Formation of Shish-Kebab Crystals in Bimodal Polyethylene under Shear at Low Temperature

Formation of shish-kebab crystals using a bimodal polyethylene system containing high molecular weight (HMW) component with different ethyl branch contents was investigated. In situ small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques were used to monitor the formation and evolution of shish-kebab structure sheared at low temperature in simple shear mode and low rate. Only the bimodal PE with no branch formed shish-kebab crystals at the shear temperature of 129 °C, and the shish length increased with the crystallization time, while bimodal PE with branch has no observable shish under the same conditions. The degree of crystallization for bimodal PE with no branch increased with time up to above 7%, while those with ethyl branch increased continually up to above 23%. Furthermore, bimodal PE’s Hermans orientation factor with no branch increased to 0.60, while those with ethyl branch only increased to a value below 0.15. This study indicated that the shish-kebab crystal formed at the low temperature of 129 °C is due to the stretch of entangled chains under shear for the bimodal PE with no branch. Only partly oriented lamellar crystals were formed for the bimodal PE with ethyl branch. All the results at the shear temperatures higher, closed to, and lower than the melting point, the modulation of shish crystals formation owing to different mechanisms of the coil-stretch transition and the stretched network by changing shear temperature was achieved in the bimodal PE samples.

Serum creatinine and cystatin C-based estimates of glomerular filtration rate are misleading in acute heart failure.

AimsWe aimed to test whether the endogenous filtration markers serum creatinine or cystatin C and equation‐based estimates of glomerular filtration rate (GFR) based on these markers appropriately reflect changes of measured GFR in patients with acute heart failure.MethodsIn this prospective cohort study of 50 hospitalized acute heart failure patients undergoing decongestive therapy, we applied an intravenous visible fluorescent injectate (VFI), consisting of a low molecular weight component to measure GFR and a high molecular weight component to correct for measured plasma volume. Thirty‐eight patients had two sequential GFR measurements 48 h apart. The co‐primary endpoints of the study were safety of VFI and plasma stability of the high molecular weight component. A key secondary endpoint was to compare changes in measured GFR (mGFR) to changes of serum creatinine, cystatin C and estimated GFR.ResultsVFI‐based GFR measurements were safe and consistent with plasma stability of the high molecular weight component and glomerular filtration of the low molecular weight component. Filtration marker‐based point estimates of GFR, when compared with mGFR, provided only moderate correlation (Pearson's r, range 0.80–0.88, depending on equation used), precision (r 2, range 0.65–0.78) and accuracy (56%–74% of estimates scored within 30% of mGFR). Correlations of 48‐h changes GFR estimates and changes of mGFR were significant (P < 0.05) but weak (Pearson's r, range 0.35–0.39). Observed decreases of eGFR by more than 15% had a low sensitivity (range 38%–46%, depending on equation used) in detecting true worsening mGFR, defined by a >15% decrease in mGFR.ConclusionsIn patients hospitalized for acute heart failure, serum creatinine‐ and cystatin C‐based predictions performed poorly in detecting actual changes of GFR. These data challenge current clinical strategies to evaluate dynamics of kidney function in acute heart failure.

Calcium (Ca2+)-regulated exopolysaccharide biosynthesis in probiotic Lactobacillus plantarum K25 as analyzed by an omics approach

Exopolysaccharide (EPS)-producing lactic acid bacteria have been widely used in dairy products, but how calcium, the main metal ion component in milk, regulates the EPS biosynthesis in lactic acid bacteria is not clear. In this study, the effect of Ca2+ on the biosynthesis of EPS in the probiotic Lactobacillus plantarum K25 was studied. The results showed that addition of CaCl2 at 20 mg/L in a semi-defined medium did not affect the growth of strain K25, but it increased the EPS yield and changed the microstructure of the polymer. The presence of Ca2+ also changed the monosaccharide composition of the EPS with decreased high molecular weight components and more content of rhamnose, though the functional groups of the polymer were not altered as revealed by Fourier transform infrared spectral analysis. These were further confirmed by analysis of the mRNA expression of cps genes, 9 of which were upregulated by Ca2+, including cps4F and rfbD associated with EPS biosynthesis with rhamnose. Proteomics analysis showed that Ca2+ upregulated most of the proteins related to carbon transport and metabolism, fatty acid synthesis, amino acid synthesis, ion transport, UMP synthesis. Specially, the increased expression of MelB, PtlIIBC, EIIABC, PtlIIC, PtlIID, Bgl, GH1, MalFGK, DhaK, and FBPase provided substrates for the EPS synthesis. Meanwhile, metabolomics analysis revealed significant change of the small molecular metabolites in tricarboxylic acid cycle, glucose metabolism and propionic acid metabolism. Among them the content of active small molecules such as polygalitol, lyxose, and 5-phosphate ribose increased, facilitating the EPS biosynthesis. Furthermore, Ca2+ activated HipB signaling pathway to inhibit the expression of manipulator repressor such as ArsR, LytR/AlgR, IscR, and RafR, and activated the expression of GntR to regulate the EPS synthesis genes. This study provides a basis for understanding the overall change of metabolic pathways related to the EPS biosynthesis in L. plantarum K25 in response to Ca2+, facilitating exploitation of its EPS-producing potential for application in probiotic dairy products.

STUDYING FEATURES OF GEL FORMATION AND RHEOLOGICAL PROCESSES OF GELATIN-BASED HYDROGELS FOR COSMETOLOGY AND MEDICINE

This article studies the features of gelation and rheological processes of gelatin-based hydrogels for cosmetology and medicine. It is shown that the study of the features of the processes of structure formation of dispersed hydrogels in water, as well as the processes of obtaining medical and cosmetic materials of various natures is extremely important in solving a number of urgent problems. In the context of cosmetic applications, the main advantage of polymer hydrogels is the possibility of their saturation with active substances even at the manufacturing stage. Viscosimetric studies of the concentration dependence of the viscosity of gelatin solutions on temperature, the results of which can be used to judge the ability of gelatin to carry out conformational transitions, showed a significant difference in the graphical dependences of the relative viscosity of diluted solutions in the temperature range 20–25 °C. It was found that in the temperature range from 20 to 25 °C macromolecules of fish gelatin carry out the conformational transition "fibrils-ball". The presented data are evidence that gelatin macromolecules in solutions tend to spiralise, therefore, gelatin molecules retained their native state and have reactivity. It was determined that with an increase in temperature to 40 °C, no significant change in the relative viscosity was noted, which determines the homogeneity of the molecular weight distribution of the components of gelatin and is confirmed by experimental data on its molecular weight composition, which indicates the presence of high molecular weight components with the maximum preserved native structure. It has been established that the most effective from the point of view of obtaining various medical, cosmetic materials and agents are compositions with the greatest time of loss of stickiness and film formation – with 25 % gelatin and 50 % milk and honey, since they will be characterized by the longest diffusion time active substances into the human body.

Influences of Molecular Structure on the Non-Isothermal Crystallization Behavior of β-Nucleated Isotactic Polypropylene

In order to explore the effect of molecular structure on the crystallization and polymorphic behavior of β-nucleated isotactic polypropylene (β-iPP), four commercial iPP samples with different average isotacticities, molecular weights and isotactic distributions were used. The relationship between the molecular structure characteristics and β-crystallization behavior were investigated by means of xylene solvent fractionation (XS), successive self-nucleation and annealing fractionation (SSA), carbon-13 nuclear magnetic resonance spectrometry (13C NMR), gel permeation chromatography (GPC), melt index (MI) and differential scanning calorimetry (DSC). Results of molecular structure characterization revealed that their isotacticity can be ranged as F401 > 5014L > F03G ≈ T38F, while the order of their isotactic distribution width is 5014L ≈ T38F > F401 ≈ F03G. Results of crystallization kinetics revealed that the molecular weight of the samples has little effect on their crystallization and polymorphic behavior. Meanwhile, crystallization activation energy Ec can be ranged as 5014L < F401 < F03G < T38F, indicating that when the molecular weight was above a certain degree, the isotacticity is the main factor affecting the crystallization ability of β-type iPP (β-iPP). The higher the isotacticity and the wider the distribution is, the stronger the β-crystallization ability is. Moreover, the β-crystallization ability of the samples is closely related to the isotacticity of the sample, which can be effectively controlled by tuning the fraction of high isotacticity with high molecular weight components.

Optical properties of dissolved organic matter in a monsoonal headwater stream, China: Insights for structure, source and riverine pCO2

Dissolved organic matter plays a fundamental geochemical role in aquatic systems. However, not much is known about interactions of dissolved organic matter characteristics, source, and partial pressure of carbon dioxide in the monsoonal streams of Asia. The ultraviolet visible and fluorescence spectroscopic indices were used as proxies for dissolved organic matter quantity and quality, and consequently associations and controls of dissolved organic matter quality, nutrients and partial pressure of carbon dioxide were examined in a monsoonal headwater River Jinshui. The source, composition, and molecular weight of dissolved organic matter showed temporal variations, mainly contributable to hydrological seasonality and potentially biological productivity. The allochthonous (land-derived) high-molecular weight components (aromatic, humification and lignin substances) were the dominant source of dissolved organic matter in the River with more terrestrial contributions in the wet season (much higher absorption coefficient at a wavelength of 350 nm and specific ultraviolet–visible absorption at 254 nm, and lower biological index and freshness index). The autochthonous low-molecular weight fractions contributed more in the dry season (significantly higher biological index and freshness index). Dissolved organic matter quality indices rather than dissolved organic carbon concentration showed significant relationships with partial pressure of carbon dioxide, this observation coupled with correlation seasonality could demonstrate the origins and controls of partial pressure of carbon dioxide. The new findings advanced the interactions of dissolved organic matter geochemistry, nutrients and partial pressure of carbon dioxide in rivers. This is critical for water environmental assessment and regional sustainable development. Further studies on discrimination and controls of dissolved organic matter quality, dissolved carbon dioxide and nutrients remain to be conducted.

Assessment of low intensivities γ-irradiation chronic influence on the state of thiol-disulphide exchange in the small intestine of rats

Today considerable attention is paid to the effects of ionizing radiation.chronic exposure in low doses and intensivity to humans and other bio-objects. The changes in the structural characteristics of the genome, nuclear, microsomal, mitochondrial, plasma membranes, cell proliferation, and the processes underlying radioresistance / radiosensitivity caused by irradiation have been experimentally studied. prolonged exposure to ionizing rays in small doses gradually causes a decrease in the endogenous reserve of thiol-dependent systems, and their complete depletion, which negatively affects the body's resistance to adverse environmental factors. There is a possibility of disturbances in the synthesis of thiol disulfide high molecular weight components. The objective: to study the state of thiol disulfide, glutathione redox system and acetylcholinesterase activity in the small intestine of rats of different sexes and ages under physiological conditions and under conditions of prolonged γ-irradiation in a total dose of 0.75 and 1.0 Gy. Results. It has been established that in a small bowel of intact mature rats after prolonged total γ-irradiation with a dose of 1.0 Gy, there were quite significant changes in the content of thiol compounds in the tissues of the small intestine. It was found that the content of SH-groups of protein origin in the tissues of the small intestine decreased relative to the age of control group animals by 28.8% and at the same time was lower than the value of males of the previous stage by 32.8%. The number of disulfide groups of protein origin in the small intestine of males three months after irradiation at a total dose of 1.0 Gy, relative to the same age control group animals, was 85.6% and at the same time was lower than the previous stage by 31.8%. Conclusions: 1.Under physiological conditions there are clear gender and age differences in the functional state of thiol-disulfide, glutathione redox system and acetylcholinesterase activity.Prolonged total γ-irradiation in the total dose of 0.75 and 1.0 Gy causes quite stable and profound changes in the functional state of the systems under study.The dependence of the detected changes on the time elapsed after radiation damage, the dose of γ-irradiation and the sex of the animals is clearly monitored.4. Females have been shown to be more radioresistant than males.

A high-throughput assay to quantify protein hydrolysis in aerobic and anaerobic wastewater treatment processes.

Proteins, an important fraction of the organic matter in wastewater, typically enter a treatment facility as high molecular weight components. These components are degraded by extracellular protein hydrolytic enzymes, denoted as proteases. Adequate protein hydrolysis monitoring is crucial, since protein hydrolysis is often a rate-limiting step in wastewater treatment. However, current monitoring tools lack a high sample throughput and reliable quantification. Here, we present an improved assay for high-throughput protein hydrolysis rate measurements in wastewater treatment applications. A BODIPY FL casein model substrate was implemented in a microplate format for continuous fluorescent quantification. Case studies on a conventional and a high-rate aerobic municipal wastewater treatment plant and a lab-scale, two-stage, anaerobic reactor provided proof-of-concept. The assay presented in this study can help to obtain monitoring-based process insights, which will in turn allow improving biological performance of wastewater treatment installations in the future. KEY POINTS: • Protein hydrolysis is a crucial step in biological wastewater treatment. • Quantification of the protein hydrolysis rate enables in-depth process knowledge. • BODIPY FL casein is a suitable model substrate for a protein hydrolysis assay. • High sample throughput was obtained with fluorescent hydrolysis quantification. Graphical abstract.

Modeling of hydrothermal processes of transformation of super-viscous oil of the Ekaterinovsky deposit in the presence of clay minerals

Using a set of physicochemical methods, the influence of hydrothermal effects on the composition of super-heavy oil of the Ekaterinovsky field in a carbon dioxide medium in the presence of a composition of catalysts - metals of variable valence in model experiments on clay rock-forming minerals was studied. Peculiarities of the transformation of the oil composition associated with the destruction of its high molecular weight components - resins and asphaltenes, and the formation of light saturated and aromatic hydrocarbons are revealed. Changes in the structural-group composition indicate an increase in the aromaticity of the products of the experiments. The greatest changes occur in the composition of resins and asphaltenes, which is reflected in a change in their structural-group composition and their paramagnetic properties. The high sorption ability of the rock to metals included in the composition of the used catalyst composition was revealed.

Refining super-viscous oil in supercritical aqueous fluid

A comparative analysis of products of hydrothermal transformation of super-viscous oil above the critical point of water at elevated temperatures of 375-385°C and pressures of 22-23 MPa in the presence of coal and oxides of iron, aluminum, copper and nickel was carried out. The regularities of changes in the structural-group and component composition, as well as the physicochemical properties of aquathermolysis products of super-viscous oil of B2 type of Ashalchinskoye field, were established. It was shown that destruction of high molecular weight components of super-viscous oil under conditions of its watermolysis in the presence of manganese and iron oxides lead to the formation of low-boiling hydrocarbon fractions. The predominant course of the destruction of resinous components, aliphatic substituents of asphaltenes and branched aliphatic structures with the redistribution of alkanes of normal structure towards their low molecular weight homologs has been established.

Characteristics of pressurized hot water extract from abalone muscle and the antioxidant ability during simulated digestion in vitro.

The physicochemical properties of pressurized hot-water extract (PHE) from abalone muscle and the antioxidant activities of its digestive products were investigated in this study. The PHE contained protein of 49.58% and carbohydrate of 41.95%. After ethanol graded precipitation, most of carbohydrate and protein in PHE were successively remained in 40% ethanol precipitate (EP40) and 80% ethanol precipitate (EP80), respectively. High proportions of Glu and Gly were found in the PHE, EP40 and EP80, but the proportion of Ala in ethanol soluble extract (ESE) reached up to 46.00%. Both PHE and EP40 were rich in glucose, while galactose and glucose were main monosaccharides in the EP80 and ESE. Based on the results of SDS-PAGE and HPLC, high molecular weight components from PHE were precipitated in the EP40, but oligopeptides and free amino acids were fractionated in EP80 and ESE. Among the PHE and the digestive products, the highest antioxidant ability was found to be EP80 hydrolysate, the IC50 values of which for scavenging activity on hydroxyl radical, DMPD radical and ABTS radical were 1.05mg/mL, 1.40mg/mL and 0.56mg/mL, respectively. It is concluded that carbohydrate of abalone muscle was dissolved more easily into hot water than protein, and protein hydrolysate of PHE might play an important role in antioxidant activity of gastrointestinal digestion.

Pressure-Sensitive Tissue Adhesion and Biodegradation of Viscoelastic Polymer Blends.

Viscoelastic blends of biodegradable polyesters with low and high molecular weight distributions have remarkably strong adhesion (significantly greater than 1 N/cm2) to soft, wet tissue. Those that transition from viscous flow to elastic, solidlike behavior at approximately 1 Hz demonstrate pressure-sensitivity yet also have sufficient elasticity for durable bonding to soft, wet tissue. The pressure-sensitive tissue adhesive (PSTA) blends produce increasingly stronger pull-apart adhesion in response to compressive pressure application, from 10 to 300 s. By incorporating a stiffer high molecular weight component, the PSTA exhibits dramatically improved burst pressure (greater than 100 kPa) when used as a tissue sealant. The PSTA's biodegradation mechanism can be switched from erosion (occurring primarily over the first 10 days) to bulk chemical degradation (and minimal erosion) depending on the chemistry of the high molecular weight component. Interestingly, fibrosis toward the PSTA is reduced when fast-occurring erosion is the dominant biodegradation mechanism.

Non-isothermal decomposition kinetics of in-chain functionalized poly(MMA-co-ethylene)

Efficient incorporation of polar monomers in polyolefin can lead to many desirable properties in the parent chain. Herein, we report the synthesis of ethylene and methyl methacrylate (MMA)-based copolymers by transition metal-catalysed reverse atom transfer radical polymerization technique with controlled ethylene feed pressure. Successful copolymerization was confirmed by 1H nuclear magnetic resonance analysis. With increasing polymerization time, resultant copolymers exhibit bimodal molecular weight distributions with controlled high molecular weight component and less-controlled low molecular weight component as confirmed by size-exclusion chromatography analysis. Morphological and crystal structures of the copolymer were established using scanning electron microscope and X-ray diffraction analysis, respectively. Thermogravimetric analysis of the copolymer under non-isothermal condition shows a two-step decomposition process with the major decomposition in the range of 320–450 °C. Based on approaches of Friedman and Flynn–Wall–Ozawa, model-free multivariate nonlinear regression analyses were performed to find out the formal mechanisms, kinetic model and its corresponding kinetic triplets. The results revealed the nth-order (Fn) mechanism responsible for the decomposition of the copolymer. The estimated kinetic parameters for the decomposition of poly(MMA-co-ethylene) copolymer were Ea= 227.80 kJ mol−1 and A = 6.76 × 1015 s−1.

Membrane fouling potential of the denitrification filter effluent and the control mechanism by ozonation in the process of wastewater reclamation

A process of denitrification filter (DNF) coupled with ultrafiltration (UF) and ozonation (DNF-UF-O3) has been widely applied to advanced nitrogen removal for wastewater reclamation. Despite of the effective removal of nitrogen by DNF, the influence of DNF stage on the operation of UF was still unclear. In this study, a laboratory filtration system was used to investigate the membrane fouling potential of DNF effluent and the fouling control of ozonation. The membrane fouling potential was proved to be increased significantly after DNF stage and alleviated with ozonation treatment. With the help of UV–vis, fluorescence spectroscopy, scanning electron microscopy (SEM) and molecular weight (MW) analysis, the change of DOM component characteristics was proved to be in accordance with the change of fouling potential. The water samples were further fractionated into six hydrophobic/hydrophilic acidic/basic/neutral fractions, among which hydrophobic acids (HOA) and hydrophobic neutrals (HON) dominated the membrane fouling potential of DNF effluent. Detailed study of each fraction revealed that higher MW components in HOA and HON played a crucial role in the fouling of UF membrane. The dominant component of membrane fouling could be degraded and removed by ozonation, and therefore significant fouling alleviation was achieved. These results indicated that in the process of wastewater reclamation, besides conventional water quality indexes, more detailed water features should also be taken into consideration to optimize the whole process. Moreover, the control effects by ozonation could be monitored simply according to the change of specific UV absorbance (SUVA) and fluorescence intensity as surrogates in engineering applications. According to these results, a modified DNF-O3-UF process with O3 dosage of 3 mg/L was proposed simply by reversing the sequence of UF and O3 with no more infrastructure. This modified DNF-O3-UF process was expected to enlarge the produce capacity of reclaimed water with much lower electricity costs and chemical consumption.

Exercise‐induced allergic reactions on desensitization to wheat after rush oral immunotherapy

The effect of oral immunotherapy (OIT) on wheat allergy is promising in terms of the potential to obtain desensitization; however, the frequency of exercise-induced allergic reactions on desensitization (EIARDs) and the associated risk factors remain to be determined. Twenty-five patients underwent rush OIT for wheat allergy, and 21 achieved the full-dose intake of wheat products (5g of wheat protein). Exercise-provocation tests were repeatedly performed after the ingestion of a full-dose wheat product. The time-course of the levels of the specific IgEs (sIgE) to wheat extract, total gliadin, deamidated gliadin, recombinant gliadin components (α/β-, γ- and ω-5-), and glutenin (high and low molecular weight) components was analyzed using ImmunoCAP® , ELISA, or IgE immunoblotting. Fourteen patients (66.7%) were diagnosed as EIARD+, which remained 5years after rush OIT in 11 patients (52.4%). There were no differences in the clinical backgrounds of the EIARD+and EIARD-patients. However, EIARD+patients showed significantly higher sIgE levels to all gliadin and glutenin components than EIARD- patients before OIT. The sIgE levels to each component decreased equally after 1 and 2years of OIT. On IgE immunoblotting, sera from all patients reacted to the multiple gluten bands, and some reacted to the water-soluble bands. The intensity of all IgE-reactive bands also became equally lighter after OIT. EIARDs were frequently observed and remained for a long period after successful OIT for wheat allergy. None of the specific wheat components were found to contribute to EIARDs.

Profiling of high molecular weight esters by flow injection analysis-high resolution mass spectrometry for the characterization of raw and archaeological beeswax and resinous substances

This work presents a method to characterize high molecular esters in beeswax and resinous substances based on the use of microwave-assisted extraction and flow injection analysis-high resolution mass spectrometry that combines the high efficiency of the extraction procedure with the advantages of high resolution mass spectrometry. This approach allows us to identify archaeological beeswax and plant resinous substances by the characterization of the survived intact high molecular weight components. By this way, several raw materials (beeswax, pine resin and pitch, and resin extracted from Euphorbia tirucalli) were studied and used as reference substances. The procedure was then tested on an adhesive dated 44–42 ka BP recovered from Border Cave (KwaZulu-Natal, Africa), allowing us to detect the high molecular weight species even after almost 50,000 years, and then used to chemically investigate unknown archaeological adhesives from Antinoopolis (Egypt), dated to the 4th-5th century AD. The results allowed us to extend our knowledge on the long-term behavior of beeswax and resinous substances.

Spectroscopy goes viral: Diagnosis of hepatitis B and C virus infection from human sera using ATR-FTIR spectroscopy

The development of a new fast, portable and reagent-free diagnostic technique for hepatitis B (HBV) and hepatitis C (HCV) viruses would be an enormous benefit to society. Here, we evalulate the ability of Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy combined with multivariate data analysis to classify human serum samples based on the presence of HBV and HCV infection. Sera samples were prepared using three different methodologies: i) Sera depsoited onto glass cover slips, airdried and placed onto the ATR crystal. ii) Whole serum dried directly onto the ATR crystal. iii) Serum separated into high and low molecular weight compounds using a filtration approach and the high molecular weight fraction placed directly onto the ATR-FTIR diamond window and dried. For methodology i) the Partial Least Squares Discriminate Analysis (PLS-DA) calibration set included 313 (70 %) samples and the validation set 93 (30 %) samples. For HBV vs control the sensitivity and specificity was found to be 69.4 % and 73.7 % (10 latent variables (LV)), respectively. For HCV vs control the sensitivity and specificity was 51.3 % and 90.9 % (LV 11), respectively. In the second set of experiments the serum samples were dried directly onto the ATR diamond. PLS-DA models were constructed using 144 (70 %) samples for the calibration set and tested using an independent test set containing 62 (30 %) samples. For HBV versus control the sensitivity and the specificity was 84.4 % and 93.1 %, respectively (LV 8). For HCV versus control the sensitivity and specificity was 80.0 % and 97.2 %, respectively (LV 9). For HBV versus HCV the sensitivity and the specificity was 77.4 % and 83.3 %, respectively (LV 5). To increase the sensitivity and specificity serum sample was fractionated into high and low molecular weight components. In PLS-DA cross validated model (LV 8) the sensitivity and specificity was 87.5 % and 94.9 %, respectively for HBV vs control (high molecular concentrate). The PLS-DA cross-validated model (LV 8) for HCV vs control high molecular fraction produced a sensitivity and specificity of 81.6 % and 89.6 %, respectively. No linear correlation was observed for sera samples spiked with known viral loads using Partial Least Squares Regression (PLS-R) modelling.Spectra of positive serum (HBV and HCV) showed a strong band observed at 1631 cm−1, which was absent in the spectra of controls and assigned to the β-pleated sheet protein marker of immunoglobulin (Ig). A band at 1093 cm−1, observed in spectra of HBV infected sera, was assigned to CC and COmodes of polysaccharide N-glycan from hepatitis B surface antigen (HBsAg). The assignment was confirmed by atomic force microsocpy infrared (AFM-IR) spectroscopy of the isolated protein. This band represents a unique marker for HBV infection. In summary, ATR-FTIR spectroscopy is a powerful tool to study blood composition and identify potential disease markers but care must be taken to ensure that the modelling is not biased by inflammation markers, which may confound diagnosis.

Diethylaminoethyl chitosan–hyaluronic acid polyelectrolyte complexes

Polysaccharide-based polyelectrolyte complexes (PECs) are of great interest for the development of drug delivery systems, as they are easily prepared and exhibit a wide range of colloidal properties. The water-soluble diethylaminoethyl chitosan (DEAE-CS) was synthesized with various degrees of substitution (DS), ranging from 26 to 113%. Analysis of the substitution pattern of DEAE-CS by different NMR techniques revealed N- and O-substitution, as well as quaternization of the tertiary amino group of the DEAE substituent; the fraction of quaternary amino groups increased with the DS. Unlike the tertiary amino groups, the quaternary amino groups did not support increases in the ζ-potential of DEAE-CS with the DS and the complexation with hyaluronic acid (HA). The influence of the PEC composition, DS of DEAE-CS, and mixing order on the size and polydispersity of PEC nanoparticles was investigated by dynamic and static light scattering. Internal disordered heterogeneous PEC nanoparticles were formed by the aggregates of several primary PECs. Disordered and structurally heterogeneous spherical complexes were formed (Rg/Rh = 1.0 ± 0.3). The obtained PECs were metastable and their properties were influenced by mixing order. The high molecular weight component (HA), being a minor component, was more exposed on the surface than was the low molecular weight DEAE-CS.

Occurrence, source, and risk assessment of atmospheric parent polycyclic aromatic hydrocarbons in the coastal cities of the Bohai and Yellow Seas, China

Parent polycyclic aromatic hydrocarbons (PPAHs) in the ambient air of the coastal cities near the Bohai and Yellow Seas were measured over a full year. The range and geometric average of total PPAH29 (29 species) were 5.16-1.22 × 103 and 118 ng/m3, respectively, with 77 ± 14% in a gaseous phase. The 16 priority components accounted for 90 ± 4% of the total mass concentration. The incremental life cancer risk (ILCR) via inhalation exposure to the PPAHs (3.17 × 10−4) was underestimated by 80%, as only the priority PPAHs were considered. The air concentrations of PPAHs in the Bohai Sea area were generally higher (p < 0.01) than those in the Yellow Sea area. A significant increase (p < 0.01) in the levels of PPAHs and large fractions of high molecular weight (HMW) components were observed in winter. Absorption by particulate organic carbon dominated in gas-particle partitioning of the PPAHs, and the seasonal variations in gas-particle partitioning of the low and moderate molecular weight compounds were more noticeable relative to the HMW species. In summer, significantly higher concentrations of PPAHs were found in the daytime than during nighttime, while the opposite case occurred in winter (p < 0.05). The positive matrix factorization (PMF) results indicated greater contributions of coal and biomass combustion to the PPAH emissions in the coastal cities of the Bohai Sea area compared with the Yellow Sea area. The burning of coal and biomass served as the main source of PPAHs in winter, while traffic exhaust was the dominant source in other seasons. The potential source contribution function (PSCF) revealed the important impacts of the external inputs on the local PPAHs via air mass transport. The contributions of the resolved emission sources to the ILCR were clearly different from those of the mass concentrations, indicating the necessity for source-oriented risk assessments.