Tailoring surface properties of paper using nanosized precipitated calcium carbonate particles

Pigment particles used in paper coatings are typically of micrometer size and consequently the thickness of the coatings is, even at its lowest, in micrometer scale. Progress in nanotechnology has given way to the development of nanosized materials to be used in coatings, yet their exploitation has not been studied to a great extent. This study examines utilization of nanosized precipitated calcium carbonate (nanoPCC) particles in nanoscale thin coating layers. In contrast to commonly used coatings, a thin nanoparticle-based coating was targeted to change the substrate surface characteristics via controlled surface structure rather than via high coat weight. A novel approach for stabilizing and modifying the nanoPCC particles with pectin and alkenyl succinic anhydride (ASA) was utilized and a nanoparticle coating with uniform particle distribution was created. The coating applied on paper substrate was hydrophobic, having a water contact angle of 125°. Particle surface modification provided dispersion stability, enabling control of the coating layer structure. The introduced concept provides a new approach to paper coatings utilizing controlled deposition of nanoparticles with extremely low coat weight, yet having high impact on substrate surface properties. Additionally, as paper is an environmentally sound product, the approach to form a controllable nanostructure on a green substrate has potential in applications outside the traditional paper products.     

Inactivation of Aerosolized Viruses in Continuous Air Flow with Axial Heating

Thermal inactivation of viruses has been studied in relevance to food sterilization, water purification, and other “non-aerosol” applications, in which heat treatment is applied for a relatively long time. No data are available on the inactivation of airborne viruses exposed to dry heat for a short time, although this is relevant to bio-defense and indoor air quality control. In this study, we investigated inactivation of aerosolized MS2 viruses in a continuous air flow chamber with axial heating resulted from exposures during ～ 0.1–1 s. For an airborne virion, the characteristic exposure temperature, T _e , was defined utilizing the air temperature profiles in the chamber. The tests were conducted at two air flow rates, Q, which allowed for establishing different thermal flow regimes and exposure time intervals. The experimentally determined inactivation factor, IF, was subjected to correction to account for the temperature profiles. At T _e up to ～ 90°C (Q = 18 L/min) and up to ～ 140°C (Q = 36 L/min), the loss of viral infectivity was relatively modest (≤ 10). However, IF increased exponentially as T _e rose from ～ 90°C to ～ 160°C (for 18 L/min) or from ～ 140°C to ～ 230°C (for 36 L/min). Under specific thermal exposure conditions (～ 170°C and ～ 250°C, respectively), IF exceeded ～ 2.4 × 10⁴ (～ 99.996% infectivity loss)—the maximum quantifiable in this study. The airborne MS2 virions exposed to hot air for < 1 s were found to have survived much higher temperatures than those subjected to thermal treatment in liquid for minutes or hours. The findings are significant for establishing limitations of the heat-based bioaerosol control methods.     

Airborne enteric coliphages and bacteria in sewage treatment plants

The concentrations of airborne culturable microorganisms were determined in wastewater and sludge treatment processes of seven sewage treatment plants. Two types of coliphages, Salmonella and total viable bacteria were sampled by the BioSampler and the numbers of faecal coliforms and enterococci were obtained from the Andersen 6-stage impactor. The BioSampler recovered higher numbers of airborne coliphage viruses than has been measured with other liquid samplers in previous studies, suggesting that this sampler has improved efficiency for sampling airborne coliphages. Airborne coliphages were detected in many stages of the wastewater or sludge treatment process. The highest microbiological air contaminations were found in pre-treatment and aerated grit separation stages of the operation. This was attributed to aerosolisation of microorganisms by mechanical handling or forced aeration. Aeration and settling processes located outdoors caused low microbial concentrations, but the brush aerator released more microorganisms into the air. Our results emphasize the necessity for controlling the exposure of sewage workers to airborne microorganisms, especially in process areas that involve mechanical agitation or forced aeration of wastewater.     

High-performance real-time quantitative RT-PCR using lanthanide probes and a dual-temperature hybridization assay

We report a time-resolved fluorescence-based, homogeneous approach for multiplex, real-time or end-point detection of PCR products. Signal generation consists of PCR associated digestion of a 5'-labeled oligonucleotide probe, rapid cooling of the reaction mixture, and hybridization of undigested probe oligonucleotides with a complementary, shorter probe that incorporates a quencher at its 3' end. The signal coming from intact fluorescent probe molecules is, thus, quenched. The fluorophores we have used are environmentally sensitive lanthanide chelates. Their signals can be measured in a time-resolved manner that eliminates most of the unspecific fluorescent background. Signal-to-noise ratios are further enhanced by the environmental sensitivity of these chelates; they exhibit a higher fluorescence intensity when free in solution than when coupled to intact probe molecules. Because of the minimal background fluorescence, the signal-to-noise ratios are higher and threshold cycles are lower than those obtained using conventional TaqMan probes. The multiplexing capacity of the assay chemistry is demonstrated through simultaneous amplification and detection of prostate specific antigen (PSA) cDNA and an internal standard mRNA (mmPSA) using probes labeled with terbium and europium. The applicability of the assay chemistry to routine clinical diagnostics is demonstrated through absolute quantification of PSA mRNA in peripheral blood.     

An Interpersonal Circumplex Model of Children's Social Goals: Links With Peer-Reported Behavior and Sociometric Status.

The objective of the present research was to develop an assessment model for children's social goals. The aims were (a) to fit children's social goals to a circumplex model and to examine links between goals and peer-reported social behaviors (aggression, withdrawal, and prosocial behavior) in a sample of 276 participants (134 girls, 11- to 12-year-olds) and (b) to replicate these findings and examine whether social behavior mediates the relationship between goals and sociometric status in an independent cross-validation sample of 310 participants (143 girls, 11- to 13-year-olds). Results showed a satisfactory fit to the circumplex model and adequate psychometric properties of the goal scales of the new measure, the Interpersonal Goals Inventory for Children. Other findings included significant and meaningful relations between goals and peer-reported behavior. Social behavior mediated the relations between goals and sociometric status. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of pre-treatment on the anthocyanin and flavonol content of black currant juice (Ribes nigrum L.) in concentration by reverse osmosis

Reverse osmosis process for the concentration of black currant juice was carried using AFC-99 tubular membrane at 30 °C and 45 bar. The contents of selected flavonols and anthocyanins were analyzed after centrifugation; enzyme treatment by Panzym Super E and by Rohapect berry followed by centrifugation; and ultrafiltration black currant juices and juice concentrates. The total soluble solid (TSS) content of the juices increased from the initial 17.6–17.9 °Brix to 24–24.8 °Brix in the case of the centrifuged juice in the concentration process. Similarly, it increased from 14.5–15.5 °Brix to 23.1–23.4 °Brix for the Panzym Super E treated juice, and from 16.1–16.9 °Brix to 22.5–23.1 °Brix for the Rohapect berry treated black currant juices. The ultrafiltered juice had the lowest initial TSS content between 14.1 and 14.9 °Brix and it increased to 22.1–23.1 °Brix. The average permeate fluxes during the concentration process were 7.3 L m⁻² h⁻¹ for the centrifuged juice, 11.9 L m⁻² h⁻¹ for the Panzym Super E treated juice, 9.2 and 13.1 L m⁻² h⁻¹ for the Rohapect berry treated and ultrafiltered juice, respectively. Analysis indicated that the enzymatic treatment resulted in the increase of anthocyanin and flavonol content of the juices. The centrifugation process decreased the amount of anthocyanins and flavonols to some extent. The juice clarified by ultrafiltration had significantly lower concentrations of anthocyanins and flavonols, while the juices treated by Panzym Super E had the highest levels of these flavonoids. This study recommends enzymatic pre-treatment by Panzym Super E, since it improves the permeate flux in reverse osmosis during the concentration process, and results in a juice concentrates highest in anthocyanins and flavonols.     

Status report of the Finnish spent fuel geologic repository programme and ongoing corrosion studies

Posiva Oy is preparing to submit an operating licence application for a spent nuclear fuel geologic repository located at Olkiluoto, Finland. The construction licence for the underground disposal facility and encapsulation plant was granted in 2015 and construction of the disposal facility began in December 2016. Safe disposal is achieved by the KBS-3 concept, developed in collaboration with Posiva's Swedish counterpart, the Swedish Nuclear Fuel and Waste Management Co, (SKB). The KBS-3 concept consists of disposal canisters (a cast iron insert and a copper overpack), surrounded by swelling bentonite and disposed in crystalline bedrock. The copper overpack ensures containment of radioactive materials and its performance against corrosion is a key driver for the design of the engineered barrier system and the repository overall. This paper describes the current status of the Posiva programme, recent learnings from the construction of the repository, and the implications for the long-term performance of the canister.     

Influence of Heavy Atom Effect on the Photophysics of Coinage Metal Carbene-Metal-Amide Emitters

The effect of the heavy metal atom on the photophysics of carbene-metal-amide (CMA) photoemitters is explored, where the metal bridge is either Au, Ag, or Cu. Spectroscopic investigations reveal the coupling mechanism responsible for communication between the singlet and triplet manifolds. The photophysical properties do not reflect expected trends based upon the heavy atom effect, as both direct coupling between charge-transfer states and spin-vibronic coupling via a ligand-centered triplet state are present. Direct coupling is weakest for CMA(Ag), increasing the importance of the spin-vibronic pathway and rendering its properties more sensitive to inter-state energy gaps than for the Au and Cu-bridged analogues. The measured activation energy correlates with the expected exchange energy of the charge-transfer state, which is also closely related to the length of the bonds joining the carbene and amide ligands, and decreases in the order CMA(Cu) > CMA(Au) > CMA(Ag). These findings reveal that reducing interference between charge-transfer and ligand-centers excited, and minimizing exchange energy, are required for developing efficient luminescent CMA complexes.     

Тhe Еffectiveness of Metal and Metalloid Sorption from Mining Influenced Waters by Natural and Modified Peat

This study investigated the sorption behaviour of natural (N peat) and HCl-acid-modified peat (HCl peat) for contaminants in water collected at a mine site in northern Finland. Batch sorption experiments were conducted at room temperature and at 5 °C. Characterization of the sorbents by FTIR and XPS revealed no substantial change in the peat’s functional groups due to the acid treatment. Generally, the N peat was a more efficient sorbent for the mine water, although the HCl peat exhibited better nickel uptake capacity (21 mg Ni/g) than the N peat (16 mg Ni/g) from synthetic water. This is attributed to the lower equilibrium pH in samples treated with the HCl peat as well as the water’s different chemical composition. At room temperature, the N peat removed As(V) (80%) and Ni (85%) at low dosage (1–2 g/L), whereas the HCl peat presented good removal of As(V) (80%) at low dosage (1 g/L) but did not achieve satisfactory removal of Ni, even at a higher dosage (4 g/L). The performance of both sorbents was significantly affected by contact time. Ni removal by N peat increased substantially with contact time whereas removals achieved by HCl peat increased slightly up to 60 min, but decreased significantly at 24 h. Unlike with HCl peat, the N peat was less efficient in the experiments conducted at 5 °C. Overall, for both sorbents, As(V) and Ni were the most efficiently removed contaminants from the mine water. HCl peat had slightly better settling properties, however, both products settled poorly, thus rendering the studied mixing and settling system unsuitable for the proposed application. Nevertheless, both peat products, and especially the N peat, exhibited high contaminant removal potential and could represent a cost-effective and sustainable option for mine water treatment.