Facing negative emotions: Evaluation of a brief training in validating communication for contact nurses in cancer care.

Background: Contact nurses in cancer care (CNCC) often face challenges when communicating with patients and their families. The overall aim was to evaluate a brief digital validation training for CNCC, to test whether it was associated with increased validation and decreased invalidation. Associations between communication skills in validation and markers of work-related stress were also investigated.

Measuring viscosity inside mesoporous silica using protein-bound molecular rotor probe.

Fluorescence spectroscopy of protein-bound molecular rotors Cy3 and Cy5 is used to monitor the effective viscosity inside the pores of two types of mesoporous silica (SBA-15 and MCF) with pore diameters between 8.9 and 33 nm. The ratio of the peak intensities is used to measure viscosity independently of solvent polarity, and the response of the lipase-bound dyes is calibrated using glycerol/water mixtures (no particles).

Interaction of DNA with water soluble complex of Nickle and formation of DNA cross-links.

Interaction of double stranded DNA with bulky and hydrophobic Salen type Schiff base complex: [N, N' Bis [3- tert-butyl-5-[triphenyl-phosphonium - methyl] - salicylidene] 1,2 ethylene-diamine nickel(III) acetate (refer to Ni Salen complex) was extensively investigated using the spectroscopic techniques and gel electrophoresis. Absorption titration experiment showed the hypochromic effect and the significant red shift of the complex absorption. In competition experiments with ethidium bromide (EB), Ni Salen complex exhibited non-competitive binding at high concentrations.

Immobilization of Enzymes in Mesoporous Silica Particles: Protein Concentration and Rotational Mobility in the Pores.

Enzyme immobilization in porous silica particles is used to improve enzyme function in biocatalytic applications. Here, we study the effective protein concentration and rotational mobility of lipase and bovine serum albumin in the pores, when confined in five types of mesoporous silica particles with different pore and particle sizes, exploiting the intrinsic UV-vis absorption and fluorescence anisotropy of the tryptophan residues. For all investigated combinations of proteins and particles, the steady-state anisotropy is higher than for the same protein in free solution, indicating a slower protein rotation inside the pores.

A fluorescence spectroscopy assay for real-time monitoring of enzyme immobilization into mesoporous silica particles.

Mesoporous silica particles are used as support material for immobilization of enzymes. Here we investigated a fluorescence-based assay for real-time monitoring of the immobilization of lipase, bovine serum albumin, and glucose oxidase into micrometer-sized mesoporous silica particles. The proteins are labeled with the dye epicocconone, and the interaction with the particles is observed as an increase in emission intensity of the protein-dye conjugates that can be quantified if correcting for a comparatively slow photobleaching.

Characterization of self-assembled DNA concatemers from synthetic oligonucleotides.

Studies of DNA-ligand interaction on a single molecule level provide opportunities to understand individual behavior of molecules. Construction of DNA molecules with repetitive copies of the same segments of sequences linked in series could be helpful for enhancing the interaction possibility for sequence-specific binding ligand to DNA. Here we report on the use of synthetic oligonucleotides to self-assembly into duplex DNA concatemeric molecules.

Sensing conformational changes in DNA upon ligand binding using QCM-D. Polyamine condensation and Rad51 extension of DNA layers.

Biosensors, in which binding of ligands is detected through changes in the optical or electrochemical properties of a DNA layer confined to the sensor surface, are important tools for investigating DNA interactions. Here, we investigate if conformational changes induced in surface-attached DNA molecules upon ligand binding can be monitored by the quartz crystal microbalance with dissipation (QCM-D) technique. DNA duplexes containing 59-184 base pairs were formed on QCM-D crystals by stepwise assembly of synthetic oligonucleotides of designed base sequences.

Construction and modeling of concatemeric DNA multilayers on a planar surface as monitored by QCM-D and SPR.

The sequential hybridization of a 534 base pair DNA concatemer layer was monitored by QCM-D and SPR, and the QCM-D data were analyzed by Voigt viscoelastic models. The results show that Voigt-based modeling gives a good description of the experimental data but only if shear viscosity and elasticity are allowed to depend on the shear frequency. The derived layer thickness, shear viscosity and elasticity of the growing film give a representation of the DNA film in agreement with known bulk properties of DNA, and reveal a maximum in film viscosity when the molecules in the layer contain 75 base pairs.

Force-induced melting of DNA--evidence for peeling and internal melting from force spectra on short synthetic duplex sequences.

Overstretching of DNA occurs at about 60-70 pN when a torsionally unconstrained double-stranded DNA molecule is stretched by its ends. During the transition, the contour length increases by up to 70% without complete strand dissociation. Three mechanisms are thought to be involved: force-induced melting into single-stranded DNA where either one or both strands carry the tension, or a B-to-S transition into a longer, still base-paired conformation.

Enzymes immobilized in mesoporous silica: a physical-chemical perspective.

Mesoporous materials as support for immobilized enzymes have been explored extensively during the last two decades, primarily not only for biocatalysis applications, but also for biosensing, biofuels and enzyme-controlled drug delivery. The activity of the immobilized enzymes inside the pores is often different compared to that of the free enzymes, and an important challenge is to understand how the immobilization affects the enzymes in order to design immobilization conditions that lead to optimal enzyme activity. This review summarizes methods that can be used to understand how material properties can be linked to changes in enzyme activity.

Heterogeneous staining: a tool for studies of how fluorescent dyes affect the physical properties of DNA.

The commonly used fluorescent dye YOYO-1 (YOYO) has, using bulk techniques, been demonstrated to stain DNA heterogeneously at substoichiometric concentrations. We here, using nanofluidic channels and fluorescence microscopy, investigate the heterogeneous staining on the single DNA molecule level and demonstrate that the dye distribution is continuous. The equilibration of YOYO on DNA is extremely slow but can be accelerated by increasing the ionic strength and/or the temperature.

Tension induces a base-paired overstretched DNA conformation.

Mixed-sequence DNA molecules undergo mechanical overstretching by approximately 70% at 60-70 pN. Since its initial discovery 15 y ago, a debate has arisen as to whether the molecule adopts a new form [Cluzel P, et al. (1996) Science 271:792-794; Smith SB, Cui Y, Bustamante C (1996) Science 271:795-799], or simply denatures under tension [van Mameren J, et al.

Short oligonucleotides aligned in stretched humid matrix: secondary DNA structure in poly(vinyl alcohol) environment.

We report that short, synthetic, double- as well as single-stranded DNA can be aligned in stretched humid poly(vinyl alcohol) (PVA) matrix, and the secondary structure (nucleobase orientation) can be characterized with linear dichroism (LD) spectroscopy. Oligonucleotides of lengths varying between 10 (3.4 nm) and 60 bases (20.

Direct probing of ion pair formation using a symmetric triangulenium dye.

The 2,6,10-tris(dialkylamino)trioxatriangulenium dyes (ATOTA(+)) are highly stabilised cationic chromophores with D(3h) symmetry. The symmetry gives rise to a degeneracy of the main electronic transition. In low polarity solvents significant splitting of this degenerate transition is observed and assigned to ion pair formation.

Spectroscopic characterization of Coomassie blue and its binding to amyloid fibrils.

Coomassie brilliant blue G-250 (CB) is the dye used frequently in the Bradford assay for protein concentration determination. In this study, we investigated how the solvent polarity and viscosity affect the CB absorption and fluorescence spectra and apply this understanding to investigate the binding of CB to lysozyme and insulin in the native and amyloid fibril states. Coomassie blue binds both to the native protein and to amyloid fibrils but gives distinctly different spectral responses.

DNA in a polyvinyl alcohol matrix and interactions with three intercalating cyanine dyes.

We investigate how DNA interacts with drugs in humid polyvinyl alcohol (PVA) films by using a homologous set of cyanine dyes (YO(+), YO-PRO(2+), and YOYO(4+)) known to intercalate into DNA with increasing affinity with increasing charge. UV-vis spectroscopy shows that the PVA matrix destabilizes all three DNA-dye complexes compared to aqueous solution but to a lesser degree as the dye charge increases. The monovalent YO is fully dissociated from DNA within minutes, whereas the dissociation of the divalent YO-PRO takes about one hour and occurs by a two-step mechanism.

Electrophoretic transport of latex particles in lipid nanotubes.

Lipid vesicles can be connected by membrane nanotubes to build networks with promising bioanalytical properties. Here we characterize electrophoretic transport in such membrane tubes, with a particular eye to how their soft-material nature influences the intratube migration. In the absence of field, the tube radius is 110 +/- 26 nm, and it remains in this range during electrophoresis even though the applied electric field causes a slight decrease in the tube radius (approximately 6-11%).

Binding of intercalating and groove-binding cyanine dyes to bacteriophage t5.

The interaction between four related cyanine dyes and bacteriophage T5 is investigated with fluorescence and absorption spectroscopy. The dyes, which differ in size, charge, and mode of DNA-binding, penetrate the capsid and bind the DNA inside. The rate of association decreases progressively with increasing dye size, from a few minutes for YO to more than 50 h for YOYO (at 37 degrees C).

Single-molecule measurements of trapped and migrating circular DNA during electrophoresis in agarose gels.

The effect of agarose gel concentration and field strength on the electrophoretic trapping of open (relaxed) circular DNA was investigated using microscopic measurements of individual molecules stained with a fluorescent dye. Three open circles with sizes of 52.5, 115, and 220 kbp were trapped by the electric field (6 V/cm) and found to be predominately fixed and stretched at a single point in the gel.

Diamond cubic phase of monoolein and water as an amphiphilic matrix for electrophoresis of oligonucleotides.

We used a cubic liquid crystal formed by the nonionic monoglyceride monoolein and water as a porous matrix for the electrophoresis of oligonucleotides. The diamond cubic phase is thermodynamically stable when in contact with a water-rich phase, which we exploit to run the electrophoresis in the useful submarine mode. Oligonucleotides are separated according to size and secondary structure by migration through the space-filling aqueous nanometer pores of the regular liquid crystal, but the comparatively slow migration means the cubic phase will not be a replacement for the conventional DNA gels.

Comparison of oligonucleotide migration in a bicontinuous cubic phase of monoolein and water and in a fibrous agarose hydrogel.

Porous hydrogels such as agarose are commonly used to analyze DNA and water-soluble proteins by electrophoresis. More recently lyotropic liquid crystals, such as the diamond cubic phase formed by the lipid monoolein and water, has become a new type of well-defined porous structure of interest for both hydrophilic and amphiphilic analytes. Here we compare these two types of matrixes by investigating the nature of retardation they confer to an oligonucleotide that migrates in their respective aqueous phases.

Comparing mono- and divalent DNA groove binding cyanine dyes -- binding geometries, dissociation rates, and fluorescence properties.

The unsymmetrical cyanine dyes BOXTO-PRO and BOXTO-MEE were derived from the DNA groove binder BOXTO, by adding a positively charged or a non-ionic hydrophilic tail to BOXTO, respectively. The main objective was to obtain more efficient DNA probes, for instance in electrophoresis and microscopy, by slowing down the dissociation of BOXTO from DNA. The interactions with mixed sequence DNA was studied with fluorescence and absorbance spectroscopy, stopped-flow dissociation and gel electrophoresis.

Bicontinuous cubic phase of monoolein and water as medium for electrophoresis of both membrane-bound probes and DNA.

Porous hydrogels such as agarose are commonly used to analyze DNA and water-soluble proteins by electrophoresis. However, the hydrophilic environment of these gels is not suitable for separation of important amphiphilic molecules such as native membrane proteins. We show that an amphiphilic liquid crystal of the lipid monoolein and water can be used as a medium for electrophoresis of amphiphilic molecules.

Electrophoretic properties of complexes between DNA and the cationic surfactant cetyltrimethylammonium bromide.

We use agarose gel electrophoresis to characterize how the monovalent catioinic surfactant cetyltrimethylammonium bromide (CTAB) compacts double-stranded DNA, which is detected as a reduction in electrophoretic DNA velocity. The velocity reaches a plateau at a ratio R = 1.8 of CTAB to DNA-phosphate charges, i.

Electrophoretic properties of DNA-modified colloidal gold nanoparticles.

Oligonucleotide-modified gold nanoparticles are used in various kinds of colorimetric DNA targeting biosensors and nanoparticle assembly techniques. Herein we focus on how the size of 13 nm gold colloids changes upon DNA modification. We have performed a series of electrophoresis experiments of particles modified both thiol specifically and nonspecifically with single- and double-stranded oligonucleotides of different lengths (12- and 25-mers).