Search results for "Brush"
showing 10 items of 158 documents
Using Copolymers to Design Tunable Stimuli-Reponsive Brushes
2020
Recently, a new design for switch sensors has been proposed that exploits a conformational transition of end-grafted minority adsorption-active homopolymers in a monodisperse polymer brush [Klushin...
Wetting of polymer liquids: Monte Carlo simulations and self-consistent field calculations
2003
Using Monte Carlo simulations and self-consistent field (SCF) theory we study the surface and interface properties of a coarse grained off-lattice model. In the simulations we employ the grand canonical ensemble together with a reweighting scheme in order to measure surface and interface free energies and discuss various methods for accurately locating the wetting transition. In the SCF theory, we use a partial enumeration scheme to incorporate single-chain properties on all length scales and use a weighted density functional for the excess free energy. The results of various forms of the density functional are compared quantitatively to the simulation results. For the theory to be accurate…
Mutations in the Bacillus thuringiensis Cry1Ca toxin demonstrate the role of domains II and III in specificity towards Spodoptera exigua larvae
2004
Several mutants of the Bacillus thuringiensis Cry1Ca toxin affected with regard to specific activity towards Spodoptera exigua were studied. Alanine was used to replace single residues in loops 2 and 3 of domain II (mutant pPB19) and to replace residues 541– 544 in domain III (mutant pPB20). Additionally, a Cry1Ca mutant combining all mutations was constructed (mutant pPB21). Toxicity assays showed a marked decrease in toxicity against S. exigua for all mutants, while they retained their activity against Manduca sexta, confirming the importance of these residues in determining insect specificity. Parameters for binding to the specific receptors in BBMV (brush border membrane vesicles) of S.…
Effects of elevated hydrogen peroxide 'strip' bleaching on surface and subsurface enamel including subsurface histomorphology, micro-chemical composi…
2007
Abstract Objectives This study examined the effects of elevated concentration hydrogen peroxide tooth whitening treatments on tooth surface and subsurface integrity. Methods Sound human molars were ground and polished to prepare an uniform substrate for bleaching treatments. A cycling treatment included alternating ex vivo human salivary exposures with bleaching treatments under conditions of controlled temperature and durations of treatment. Bleaching was carried out with prototype bleaching strips containing hydrogen peroxide gel at 13% and 16% concentrations. A non-bleached group was used as a control. Treatments included 28 h of total bleaching exposure in vitro . Surface color was meas…
Molecular dynamics simulations of capillary rise experiments in nanotubes coated with polymer brushes.
2007
The capillary filling of a nanotube coated with a polymer brush is studied by molecular dynamics simulations of a coarse-grained model, assuming various conditions for the fluid-wall and fluid-brush interactions. Whereas the fluid is modeled by simple point particles interacting with Lennard-Jones forces, the (end-grafted, fully flexible) polymers that form the brush coating are described by a standard bead-spring model. Our experiments reveal that capillary filling is observed even for walls that would not be wetted by the fluid, provided the polymer brush coating itself wets. Generally, it is found that the capillary rise always proceeds through a t1/2 law with time t while the underlying…
Role of AMPA receptor desensitization in short term depression : lessons from retinogeniculate synapses
2021
Repetitive synapse activity induces various forms of short-term plasticity. The role of presynaptic mechanisms such as residual Ca2+ and vesicle depletion in short-term facilitation and short-term depression is well established. On the other hand, the contribution of postsynaptic mechanisms such as receptor desensitization and saturation to short-term plasticity is less well known and often ignored. In this review, I will describe short-term plasticity in retinogeniculate synapses of relay neurons of the dorsal lateral geniculate nucleus (dLGN) to exemplify the synaptic properties that facilitate the contribution of AMPA receptor desensitization to short-term plasticity. These include high …
Biopsy vs. brushing: comparison of two sampling methods for the detection of HPV-DNA in squamous cell carcinoma of the oral cavity
2012
Background: HR HPV infection was proposed as aetiological factor of oral squamous cell carcinomas (OSCC). HPV frequency in OSCC is highly variable, due to the discrepancy in oral sampling procedures, HPV testing methods and inclusion criteria regarding tumour site (strictly oral cavity vs. nearby structures). Our aim was to compare HPV DNA frequency and type-specific distribution in paired cytological and histological samples of SCC strictly located in oral cavity. The correlation between HPV detection rate by each method of sampling and demographical, behavioural and clinical-pathological variables was also examined. Patients and methods: HPV DNA was detected in brushed cells and formalin-…
Clinical Validation of 13-gene DNA Methylation Analysis from Oral Brushing: A Non Invasive Sampling Procedure for Early Detection of Oral Squamous Ce…
2019
In a recent study our research group described a non-invasive sampling procedure based on [...]
DEFECTIVE JEJUNAL BRUSH BORDER Na+/H+ EXCHANGE IN LETHAL FAMILIAN PROTRACTED DIARRHOEA
1989
The clinical spectrum of disease associated with the recently described defect in jejunal brush border membrane (BBM) Na+/H+ exchange remains poorly defined. We describe a further, lethal case of protracted diarrhoea in a child from a family in whom 2 previous siblings died of protracted diarrhoea at 2 and 11 months. The patient, a boy, was born at term weighing 2.9 kg and was admitted at 6d with profuse watery diarrhoea, severe dehydration and metabolic acidosis. Parenteral nutrition was started but the diarrhoea persisted, and he developed severe necrotising enterocolitis requiring an ileostomy. A high-output secretory diarrhoea persisted during nil by mouth (ileostomy fluid mmol/l: Na+ 1…
Adjuvant Effect of Titanium Brushes in Peri-Implant Surgical Treatment: A Systematic Review
2021
Background: the prognosis of peri-implant surgery can be affected by poor decontamination of the implant surface, which could be improved with the use of titanium brushes. The objectives of this systematic review were to evaluate the effectiveness of titanium brushes in the decontamination of the implant surface in terms of plaque index, probing depth, bleeding on probing and bone loss/gain; as well as its effectiveness according to the type of peri-implant bone defect. Methods: an electronic search was carried out in the PubMed, Scopus, Cochrane and Embase databases, as well as a manual search. The search strategy included four keywords: “Peri-implantitis”, “Periimplantitis”, “Implant Surf…