Capillary pressure of van der Waals liquid nanodrops

The dependence of the surface tension on a nanodrop radius is important for the new-phase formation process. It is demonstrated that the famous Tolman formula is not unique and the size-dependence of the surface tension can distinct for different systems. The analysis is based on a relationship between the surface tension and disjoining pressure in nanodrops. It is shown that the van der Waals interactions do not affect the new-phase formation thermodynamics since the effect of the disjoining pressure and size-dependent component of the surface tension cancel each other.Comment: The paper is dedicated to the 80th anniversary of A.I. Rusano

Evaluation design of a systematic, selective, internet-based, Chlamydia screening implementation in the Netherlands, 2008-2010: implications of first results for the analysis

A selective, systematic, Internet-based, Chlamydia Screening Implementation for 16 to 29-year-old residents started in three regions in the Netherlands in April 2008: in the cities of Amsterdam and Rotterdam and a more rural region, South Limburg. This paper describes the evaluation design and discusses the implications of the findings from the first screening round for the analysis. The evaluation aims to determine the effects of screening on the population prevalence of Chlamydia trachomatis after multiple screening rounds. A phased implementation or 'stepped wedge design' was applied by grouping neighbourhoods (hereafter: clusters) into three random, risk-stratified blocks (A, B and C) to allow for impact analyses over time and comparison of prevalences before and after one or two screening rounds. Repeated simulation of pre- and postscreening Chlamydia prevalences was used to predict the minimum detectable decline in prevalence. Real participation and positivity rates per region, block, and risk stratum (high, medium, and low community risk) from the 1st year of screening were used to substantiate predictions. The results of the 1st year show an overall participation rate of 16% of 261,025 invitees and a positivity rate of 4.2%, with significant differences between regions and blocks. Prediction by simulation methods adjusted with the first-round results indicate that the effect of screening (minimal detectable difference in prevalence) may reach significance levels only if at least a 15% decrease in the Chlamydia positivity rate in the cities and a 25% decrease in the rural region after screening can be reached, and pre- and postscreening differences between blocks need to be larger. With the current participation rates, the minimal detectable decline of Chlamydia prevalence may reach our defined significance levels at the regional level after the second screening round, but will probably not be significant between blocks of the stepped wedge design. Evaluation will also include other aspects and prediction models to obtain rational advice about future Chlamydia screening in the Netherland

Protein adsorption on preadsorbed polyampholytic monolayers

The adsorption behaviour of five different globular proteins on pure silicon substrates and on preadsorbed polyampholytic monolayers has been investigated as a function of protein concentration. The prelayers were prepared by adsorption of the ampholytic diblock copolymer poly(methacrylic acid)-block-poly ((dimethylamino)ethyl methacrylate) (PMAA-b-PDMAEMA). This polyampholyte adsorbs in densely packed micelles directly from aqueous solution. Ellipsometry was used to determine the amount of adsorbed polyampholyte and protein. While ATR-IR spectroscopy gives information about the adsorption and desorption behaviour of the preadsorbed polyampholytic layer, the lateral structures of the dried films were investigated by scanning force microscopy (SFM). The amount of protein adsorbed was found to be strongly influenced by the preadsorbed polyampholyte compared to the adsorption on the pure silicon substrates. No displacement of the polyampholyte by the proteins was detected. In most cases the protein adsorption was reduced by the preadsorbed polyampholytic layer. The observed trends are explained by the change in electrostatic and hydrophilic characteristics of the substrates. Furthermore, the entropy of adsorption has to be taken into account.Peer reviewe

Nanoscale Confinement and Fluorescence Effects of Bacterial Light Harvesting Complex LH2 in Mesoporous Silicas

Many key chemical and biochemical reactions, particularly in living cells, take place in confined space at the mesoscopic scale. Toward understanding of physicochemical nature of biomacromolecules confined in nanoscale space, in this work we have elucidated fluorescence effects of a light harvesting complex LH2 in nanoscale chemical environments. Mesoporous silicas (SBA-15 family) with different shapes and pore sizes were synthesized and used to create nanoscale biomimetic environments for molecular confinement of LH2. A combination of UV-vis absorption, wide-field fluorescence microscopy, and in situ ellipsometry supports that the LH2 complexes are located inside the silica nanopores. Systematic fluorescence effects were observed and depend on degree of space confinement. In particular, the temperature dependence of the steady-state fluorescence spectra was analyzed in detail using condensed matter band shape theories. Systematic electronic-vibrational coupling differences in the LH2 transitions between the free and confined states are found, most likely responsible for the fluorescence effects experimentally observed

Polyelectrolyte Adsorption on Solid Surfaces: Theoretical Predictions and Experimental Measurements

This work utilizes a combination of theory and experiments to explore the adsorption of two different cationic polyelectrolytes onto oppositely charged silica surfaces at pH 9. Both polymers, poly(diallyldimethylammonium chloride), PDADMAC, and poly(4-vinyl N-methylpyridinium iodide), PVNP, are highly charged and highly soluble in water. Another important aspect is that a silica surface carries a relatively high surface charge density at this pH level. This means that we have specifically chosen to investigate adsorption under conditions where electrostatics can be expected to dominate the interactions. Of specific focus in this work is the response of the adsorption to the addition of simple salt (i.e., a process where electrostatics is gradually screened out). Theoretical predictions from a recently developed correlation-corrected classical density functional theory for polyelectrolytes are evaluated by direct quantitative comparisons with corresponding experimental data, as obtained by ellipsometry measurements. We find that, at low concentrations of simple salt, the adsorption increases with ionic strength, reaching a maximum at intermediate levels (about 200 mM). The adsorption then drops but retains a finite level even at very high salt concentrations, indicating the presence of nonelectrostatic contributions to the adsorption. In the theoretical treatment, the strength of this relatively modest but otherwise largely unknown nonelectrostatic surface affinity was estimated by matching predicted and experimental slopes of adsorption curves at high ionic strength. Given these estimates for the nonelectrostatic part, experimental adsorption data are essentially captured with quantitative accuracy by the classical density functional theory

Nicotiana tabacum L. cv. Solaris: an innovative forage for dairy heifers

Nicotiana tabacum L. cv. Solaris: an innovative forage for dairy heifers A. Fatica1, F. Di Lucia2, F. Fantuz3, H.F. De Feijter2, B.P. Brandt2 and E. Salimei1 1Università degli Studi del Molise, Dip. Agricoltura, Ambiente, Alimenti, via de Sanctis, 86100, Campobasso, Italy, 2Sunchem BV, Johann Siegerstraat 20, 1096 BH Amsterdam, the Netherlands, 3Università degli Studi di Camerino, Scuola di Bioscienze e Medicina Veterinaria, Via Gentile III Da Varano, 62032, Camerino, Italy; [email protected] The chemical composition of Nicotiana tabacum L. cv Solaris has been studied and its biomass has been successfully conserved by ensiling (SiloSolaris). The aim of this trial was to investigate the effects of the innovative ensiled forage in heifers’ diet. Sixteen growing heifers of Friesian breed, weighing 220-360 kg and aged 8-16 months, were selected and divided in two homogeneous groups, Control (CTR) and SiloSolaris (SS) Group. Balanced and nutritionally equivalent rations were developed based on the nutritional needs, age and weight: CTR Group received 2.3 kg of concentrates mixture/head and 5-6 kg of hay/head daily, while SS Group was daily fed with 2.3 kg of concentrates mixture/head, 3.25-5.5 kg of hay/head and 0.5 kg (in the adaptation phase, 20 d) to 5 kg of SiloSolaris/ head. The trial lasted 49 days. Body condition (BCS), faecal consistency (FS) and locomotion (LS) were scored on each animal, according to the literature. In addition, the investigated consumption of feedstuffs (offered-refusals), body weight (WG) and average daily gain (ADG) were monitored. The effect of the dietary treatment on dry matter (DM) consumption, WG, ADG, BCS, FS and LS were processed by analysis of the variance, also considering the covariate effect of values at d 0, when significant. Significance was declared at P<0.05. In average, DM intake was 5.8 and 6.5 kg, respectively for SS and CTR heifers. ADG was 0.96 vs 0.88 kg/d for SS and CTR group (P>0.05). Taken together, the results suggest that N. tabacum L. cv. Solaris ensiled biomass is appreciated by Frisian heifers and did not negatively affect both growth performances and animal welfare. In a view of circular and green economy, this study represents a further successful proof of this innovative multitasking (energy and animal feeding) crop, able of recovering the ‘know-how’ of the traditional tobacco cultivation in Centre-South Italy

Study on Nicotiana tabacum L. cv Solaris as a source of biomass for animal feeding

Study on Nicotiana tabacum L. cv Solaris as a source of biomass for animal feeding A. Fatica1, A. Alvino1, S. Marino1, F. Di Lucia2, H.F. De Feijter2, B.P. Brandt2, F. Fantuz3 and E. Salimei1 1Università degli Studi del Molise, Dip. Agricoltura, Ambiente, Alimenti, via de Sanctis, 86100, Campobasso, Italy, 2Sunchem BV, Johann Siegerstraat 20, 1096 BH Amsterdam, the Netherlands, 3Università degli Studi di Camerino, Scuola di Bioscienze e Medicina Veterinaria, Via Gentile III Da Varano, 62032, Camerino, Italy; [email protected] While a deep crisis is affecting the smoke tobacco cultivation in Italy, the non GMO Nicotiana tabacum L. cv. Solaris has been developed (PCT/IB/2007/053412) as ‘energy crop’, since its maximized production of flowers/seeds are rich in oil used as biofuel. In certain climatic conditions, after the harvest of the inflorescences, a second harvest of biomass is possible. The aim of this study is to assess the use of this biomass as an innovative forage. In the triennium 2016-2018, Solaris biomass samples (n=15) were collected in three experimental sites (Vicenza, Chieti and Perugia), dried and chopped at 4 cm and analysed for chemical constituents (humidity, crude protein, crude oil and fat, crude ash, neutral detergent fibre, acid detergent fibre and acid detergent lignin), sugars (glucose, fructose, sucrose), starch, total alkaloids (expressed as nicotine), minerals (Ca, P, Mg, K, Na and chlorides), according to official analytical methods. Descriptive statistical analysis of data was performed and results are reported on a dry matter basis (mean ± standard deviation, per 100 g DM). Results allow to define the Solaris biomass as a good quality forage, in terms of crude protein (19.0±2.4 g), crude oil and fats (7.9±4.06 g) and fibre contents (46.6±4.1 g NDF; 37.5±5.0.g ADF), despite high levels of lignin (12.9±3.9 g ADL), ash content (17.2±2.4 g) and calcium content (2.5±0.6 g Ca). The content of non-structural carbohydrates (sugars and starch) allows the use of Solaris biomass as silage. The average content of total alkaloids was 350±185 mg, which is much lower than values reported for smoking tobacco varieties. The results confirm the use of cv. Solaris from the second harvest biomass as a good quality forage, adding value to the Solaris multitasking attitude as a source o