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

Multivalent Patchy Colloids for Quantitative 3D Self-Assembly Studies.

We report methods to synthesize sub-micron- and micron-sized patchy silica particles with fluorescently labeled hemispherical titania protrusions, as well as routes to efficiently characterize these particles and self-assemble these particles into non-close-packed structures. The synthesis methods expand upon earlier work in the literature, in which silica particles packed in a colloidal crystal were surface-patterned with a silane coupling agent. Here, hemispherical amorphous titania protrusions were successfully labeled with fluorescent dyes, allowing for imaging by confocal microscopy and super-resolution techniques. Confocal microscopy was exploited to experimentally determine the numbers of protrusions per particle over large numbers of particles for good statistical significance, and these distributions were compared to simulations predicting the number of patches as a function of core particle polydispersity and maximum separation between the particle surfaces. We self-assembled these patchy particles into open percolating gel networks by exploiting solvophobic attractions between the protrusions

Multivalent Patchy Colloids for Quantitative 3D Self-Assembly Studies.

We report methods to synthesize sub-micron- and micron-sized patchy silica particles with fluorescently labeled hemispherical titania protrusions, as well as routes to efficiently characterize these particles and self-assemble these particles into non-close-packed structures. The synthesis methods expand upon earlier work in the literature, in which silica particles packed in a colloidal crystal were surface-patterned with a silane coupling agent. Here, hemispherical amorphous titania protrusions were successfully labeled with fluorescent dyes, allowing for imaging by confocal microscopy and super-resolution techniques. Confocal microscopy was exploited to experimentally determine the numbers of protrusions per particle over large numbers of particles for good statistical significance, and these distributions were compared to simulations predicting the number of patches as a function of core particle polydispersity and maximum separation between the particle surfaces. We self-assembled these patchy particles into open percolating gel networks by exploiting solvophobic attractions between the protrusions

Main-Sequence Stars and the Star Formation History of the Outer Disk in the Large Magellanic Cloud

Using the Wide Field Planetary Camera 2 on the Hubble Space Telescope, we have obtained a deep color-magnitude diagram in V- and I-band equivalents for more than 2000 stars in a patch of the outer disk of the Large Magellanic Cloud LMC). Aperture photometry is feasible from these data with good signal-to-noise ratio for stars with V ≤ 25, which allows us for the first time to construct a color magnitude diagram for LMC disk stars on the lower main sequence, extending beyond the oldest main sequence turnoff point. We analyze the structure of the main-sequence band and overall morphology of the color-magnitude diagram to obtain a star formation history for the region. A comparison between the distribution of stars across the main-sequence band for M_v ≤ 4 and a stellar population model constrains historical star formation rates within the past 3 Gyr. The stellar populations in this region sample the outer LMC disk for stars with ages of 1 Gyr or older that have had time to spatially mix. The structure of the main-sequence band requires that star formation occurred at a roughly constant rate during most of the past ≈ 3 Gyr. However, the distribution of subgiant stars indicate that a pronounced peak in the star formation rate likely occurred about 2 Gyr ago, prior to which the star formation rate had not been enhanced for several Gyr. Studies over timescales of more than 3 Gyr require a separation of the effects of star formation history and the chemical evolution on the LMC color-magnitude diagrams, which is difficult to achieve without additional constraints. If lower main-sequence stars in the LMC have moderate metallicities, then the age for most LMC disk stars is less than about 8 Gyr

CD81 is dispensable for hepatitis C virus cell-to-cell transmission in hepatoma cells

Hepatitis C virus (HCV) infects cells by the direct uptake of cell-free virus following virus engagement with specific cell receptors such as CD81. Recent data have shown that HCV is also capable of direct cell-to-cell transmission, although the role of CD81 in this process is disputed. Here, we generated cell culture infectious strain JFH1 HCV (HCVcc) genomes carrying an alanine substitution of E2 residues W529 or D535 that are critical for binding to CD81 and infectivity. Co-cultivation of these cells with naïve cells expressing enhanced green fluorescent protein (EGFP) resulted in a small number of cells co-expressing both EGFP and HCV NS5A, showing that the HCVcc mutants are capable of cell-to-cell spread. In contrast, no cell-to-cell transmission from JFH1ΔE1E2-transfected cells occurred, indicating that the HCV glycoproteins are essential for this process. The frequency of cell-to-cell transmission of JFH1W529A was unaffected by the presence of neutralizing antibodies that inhibit E2–CD81 interactions. By using cell lines that expressed little or no CD81 and that were refractive to infection with cell-free virus, we showed that the occurrence of viral cell-to-cell transmission is not influenced by the levels of CD81 on either donor or recipient cells. Thus, our results show that CD81 plays no role in the cell-to-cell spread of HCVcc and that this mode of transmission is shielded from neutralizing antibodies. These data suggest that therapeutic interventions targeting the entry of cell-free HCV may not be sufficient in controlling an ongoing chronic infection, but need to be complemented by additional strategies aimed at disrupting direct cell-to-cell viral transmission

Computed tomography coronary angiography accuracy in women and men at low to intermediate risk of coronary artery disease

Objectives To investigate the diagnostic accuracy of CT coronary angiography (CTCA) in women at low to intermediate pre-test probability of coronary artery disease (CAD) compared with men. Methods In this retrospective study we included symptomatic patients with low to intermediate risk who underwent both invasive coronary angiography and CTCA. Exclusion criteria were previous revascularisation or myocardial infarction. The pre-test probability of CAD was estimated using the Duke risk score. Thresholds of less than 30 % and 30-90 % were used for determining low and intermediate risk, respectively. The diagnostic accuracy of CTCA in detecting obstructive CAD (≥50 % lumen diameter narrowing) was calculated on patient level. P<0.05 was considered significant. Results A total of 570 patients (46 % women [262/570]) were included and stratified as low (women 73 % [80/109]) and intermediate risk (women 39 % [182/461]). Sensitivity, specificity, PPV and NPV were not significantly different in and between women and men at low and intermediate risk. For women vs. me

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

Integrated analysis of pain, health-related quality of life, and analgesic use in patients with metastatic castration-resistant prostate cancer treated with Radium-223

BACKGROUND: Radium-223 (Ra-223), an alpha-emitting radiopharmaceutical, established an improved overall survival and health-related quality of life (HRQoL) in symptomatic metastatic castration-resistant prostate cancer (mCRPC) patients. However, effects on pain were not specifically evaluated. Here we assess integrated HRQoL, pain, and opioid use in a contemporary, more extensively pretreated, symptomatic and asymptomatic mCRPC population. METHODS: mCRPC patients scheduled for Ra-223 treatment were included and analyzed for HRQoL, pain, and opioid use, using Functional Assessment of Cancer Therapy-Prostate (FACT-P) and Brief Pain Inventory-Short Form (BPI-SF) questionnaires and recording of opioid use and dosage, respectively. Primary outcome measure was the percentage of patients experiencing a complete pain response (score of 0 on the BPI-SF Worst pain item and no increase in daily use of analgesics). A complete or partial pain response (better BPI-SF score and decrease in opioid use) and a better or no change in HRQoL was evaluated as an integrated overall clinical response (IOCR). Secondary endpoints included the time to pain progression (TPP) and Total FACT-P deterioration (TTFD), defined as time from first Ra-223 treatment to clinical meaningful increase in BPI-SF Worst pain item score and Total FACT-P score, respectively. RESULTS: This registry included 300 patients, of whom 105 (35%) were evaluable for FACT-P and BPI-SF during Ra-223 treatment. Forty-five (43%) patients had pain at baseline (PAB) (BPI-SF Worst pain score 5-10 points) and 60 (57%) had no pain at baseline (no-PAB) (BPI-SF Worst pain score 0-4 points). Complete pain response was achieved in 31.4% of the patients, while 58% had an IOCR. The median TTP and TTFD were 5.6 and 5.7 months, respectively, while the difference between PAB and no-PAB patients was not significant. CONCLUSIONS: In contemporary, extensively pretreated mCRPC patients, Ra-223 treatment induced complete pain responses while integrated analysis of HRQoL, pain response, and opioid use demonstrated that the majority of patients derive clinical benefit