The effect of disinfectant agents in eliminating the contamination of dental unit water

High concentrations of water-borne organisms cause multiple public health problems. Contamination of water exiting the dental unit water lines could be inhibited with the use of some disinfectants. The purpose of this investigation was to establish the effect of two disinfectants and to test their capacity to eliminate colony forming units (CFU) per mL. Vacuum lines of four chairs were treated for a total of 2 weeks. Two disinfectants (Bio(R) 2000 and Alpron(R)) were used as per manufacturer's instructions. Water samples for hetereothrophic counts from each unit's air/water syringe line were collected before treating the first patient of the day. Baseline, daily, first and second week samples of 10 mL were plated on blood agar plates and eosin ethylene blue agar. For meosifilic bacterial counts, Mueller Hinton agar plates with 1 mL direct and 1/10 were used in sterile serum and CFU were counted. The suspected colonies were further evaluated using API 20E and API 20NE. No Gram(-) opportunistic pathogens were found during the entire observation. Baseline contamination level (>102 CFU mL(-1)) without use of disinfectants was significantly higher (P <0.0001) than at both first and second weeks when disinfectants were used. No colony was formed when Bio 2000 was used after both first and second weeks, whereas small number of CFU mL(-1) was found at the end of the first week when Alpron

Spatially controlled occlusion of polymer-stabilized gold nanoparticles within ZnO

In principle, incorporating nanoparticles into growing crystals offers an attractive and highly convenient route for the production of a wide range of novel nanocomposites. Herein we describe an efficient aqueous route that enables the spatially controlled occlusion of gold nanoparticles (AuNPs) within ZnO crystals at up to 20 % by mass. Depending on the precise synthesis protocol, these AuNPs can be (i) solely located within a central region, (ii) uniformly distributed throughout the ZnO host crystal or (iii) confined to a surface layer. Remarkably, such efficient occlusion is mediated by a non-ionic water-soluble polymer, poly(glycerol monomethacrylate)70 (G70 ), which is chemically grafted to the AuNPs; pendent cis-diol side groups on this steric stabilizer bind Zn2+ cations, which promotes nanoparticle interaction with the growing ZnO crystals. Finally, uniform occlusion of G70 -AuNPs within this inorganic host leads to faster UV-induced photodegradation of a model dye

Incorporating Diblock Copolymer Nanoparticles into Calcite Crystals: Do Anionic Carboxylate Groups Alone Ensure Efficient Occlusion?

New spherical diblock copolymer nanoparticles were synthesized via RAFT aqueous dispersion polymerization of 2- hydroxypropyl methacrylate (HPMA) at 70 °C and 20% w/w solids using either poly(carboxybetaine methacrylate) or poly(proline methacrylate) as the steric stabilizer block. Both of these stabilizers contain carboxylic acid groups, but poly(proline methacrylate) is anionic above pH 9.2, whereas poly(carboxybetaine methacrylate) has zwitterionic character at this pH. When calcite crystals are grown at an initial pH of 9.5 in the presence of these two types of nanoparticles, it is found that the anionic poly(proline methacrylate)-stabilized particles are occluded uniformly throughout the crystals (up to 6.8% by mass, 14.0% by volume). In contrast, the zwitterionic poly(carboxybetaine methacrylate)- stabilized particles show no signs of occlusion into calcite crystals grown under identical conditions. The presence of carboxylic acid groups alone therefore does not guarantee efficient occlusion: overall anionic character is an additional prerequisite

Thermal–electrical transport of high purity, melt impregnated, polycrystalline MgB2

In the polycrystalline superconductor MgB2 the fraction of cross section that carries electrical current was previously shown to be obtained from the normal state electrical resistivity. The latest single crystal measurements show the thermal transport properties of MgB2 to be dominated by electrical transport. For the first time we apply the electrical cross section to the thermal conductivity of three polycrystalline samples with different grain size and porosity. It is found that the results can be readily discussed in the context of granular thermal–electrical properties consisting of common temperature dependent transport properties independent of grain size and porosity. The result gives an alternative interpretation to the temperature dependent thermal transport than given in previous publications

Impact of postmenopausal vaginal discomfort on sex and relationships in Brazil: the CLOSER survey.

The CLOSER (CLarifying Vaginal Atrophy's Impact On SEx and Relationships) survey investigated how postmenopausal vaginal atrophy (VA) affects relationships between Brazilian women and male partners.Postmenopausal women (age 55-65 years) with VA, and male partners of women with the condition, completed an online survey on the impact of VA and local estrogen treatment on intimacy and relationships.A total of 360 women and 352 men from Brazil were included. Women (83%) and men (91%) reported that they were comfortable discussing VA with their partners. Women's key source of information on VA was health-care providers (HCPs), but 44% felt that not enough information is available. VA caused 70% of women to avoid sexual intimacy and resulted in less satisfying sex. VA had a negative impact on women's feelings and self-esteem. Women (76%) and men (70%) both reported that treatment with vaginal estrogen improved their sexual relationship, primarily by alleviating women's pain during sex. Women (56%) and men (59%) felt closer to each other after treatment.VA had a negative impact on sexual relationships for both women and men in Brazil, and reduced women's self-confidence. Vaginal hormone therapy improved couples' sexual relationships. A proactive attitude of HCPs is essential to educate women on VA and the potential benefits of treatment

Strain-relief by single dislocation loops in calcite crystals grown on self-assembled monolayers

Most of our knowledge of dislocation-mediated stress relaxation during epitaxial crystal growth comes from the study of inorganic heterostructures. Here we use Bragg coherent diffraction imaging to investigate a contrasting system, the epitaxial growth of calcite (CaCO3) crystals on organic self-assembled monolayers, where these are widely used as a model for biomineralization processes. The calcite crystals are imaged to simultaneously visualize the crystal morphology and internal strain fields. Our data reveal that each crystal possesses a single dislocation loop that occupies a common position in every crystal. The loops exhibit entirely different geometries to misfit dislocations generated in conventional epitaxial thin films and are suggested to form in response to the stress field, arising from interfacial defects and the nanoscale roughness of the substrate. This work provides unique insight into how self-assembled monolayers control the growth of inorganic crystals and demonstrates important differences as compared with inorganic substrates

3D Visualisation of Additive Occlusion and Tunable Full-Spectrum Fluorescence in Calcite

From biomineralization to synthesis, organic additives provide an effective means of controlling crystallisation processes. There is growing evidence that these additives are often occluded within the crystal lattice, where this promises an elegant means of creating nanocomposites and tuning physical properties. Here, we use the incorporation of sulfonated fluorescent dyes to gain new understanding of additive occlusion in calcite (CaCO3), and to link morphological changes to occlusion mechanisms. We demonstrate that these additives are incorporated within specific zones, as defined by the growth conditions, and show how occlusion can govern changes in crystal shape. Fluorescence spectroscopy and lifetime imaging microscopy also show that the dyes experience unique local environments within different zones. Our strategy was then extended to simultaneously incorporate mixtures of dyes, whose fluorescence cascade creates calcite nanoparticles that fluoresce white. This offers a simple strategy for generating biocompatible and stable fluorescent nanoparticles whose output can be tuned as required

Physical Confinement Promoting Formation of Cu2O−Au Heterostructures with Au Nanoparticles Entrapped within Crystalline Cu2O Nanorods

Building on the application of cuprite (Cu2O) in solar energy technologies and reports of increased optical absorption caused by metal-to-semiconductor energy transfer, a confinement-based strategy was developed to fabricate high aspect ratio, crystalline Cu2O nanorods containing entrapped gold nanoparticles (Au nps). Cu2O was crystallized within the confines of track-etch membrane pores, where this physical, assembly based method eliminates the necessity of specific chemical interactions to achieve a well-defined metal−semiconductor interface. With high-resolution scanning/transmission electron microscopy (S/TEM) and tomography, we demonstrate the encasement of the majority of Au nps by crystalline Cu2O and show crystalline Cu2O−Au interfaces that are free of extended amorphous regions. Such nanocrystal heterostructures are good candidates for studying the transport physics of metal/semiconductor hybrids for optoelectronic applications