Brush Material Research Articles

The diagnostic accuracy of colonoscopic brush cytology in diagnosis of colorectal malignancies: A study of 49 patients.

To find the spectrum and frequency of lower gastrointestinal malignancies and diagnostic accuracy of colonoscopic brush cytology in their diagnosis. This was a prospective study carried out on 49 patients in the Department of Pathology over 1 year. Brushing material was smeared directly onto at least two clean glass slides. The air dried smears were stained with May Grunwald Giemsa stain. The endoscopic biopsies were examined grossly and were fixed in 10% formalin, processed and stained with Hematoxylin and Eosin stain, respectively. Special stains were used wherever required. The study was done on 49 patients presented with colorectal and anal lesions. Age of the patients ranged from 17 to 72 years with male to female ratio being 1.57:1. On statistical analysis, the sensitivity of colonoscopic brush cytology was found to be 85.71% and specificity 61.53%. The accuracy came out to be 79.16%. Brush cytology is a reliable, safe, inexpensive, and rapid method of diagnosing gastrointestinal lesions. Since brushing is a relatively noninvasive procedure, routine use of brushings of colonoscopically visible lesions should be done, in addition, to biopsy to increase the diagnostic yield.

Tooth loss and associated risk factors among rural population of Wardha District: A cross-sectional study

Introduction: Regular dental care and daily cleansing habits are one of the key aspects of keeping healthy teeth for a lifetime. Common Indian concept is, with age people become more prone to oral health problems. If they follow their oral hygiene practices meticulously, then age may not act as a risk factor for tooth loss. Aim: The aim of this study is to evaluate the risk factors associated with tooth loss among adults and the elderly among the rural population of Wardha District. Materials and Methods: In this cross-sectional study, among the rural population, two World Health Organization index age groups (35–44 and 65–74 years) were selected. A self-administered questionnaire was distributed, and complete clinical oral examination was done. The data were statistically analyzed using descriptive statistics and Chi-square test. The value of P < 0.05 was considered statistically significant. Results: Nearly 75.3% of laborers were partially edentulous. Habits, including smoking, tobacco chewing, and alcohol consumption, had an impact on tooth loss. Patients suffering from diabetes and hypertension had 97.5% and 100% had tooth loss, respectively. Regarding the first visit to the dentist, 65.6% population underwent dental treatment from the dental college in the vicinity. “No dental problems” were reported by 68.4% of patients of the total population and among them 81.3% were edentulous. Regarding “Self-perceived treatment” the result revealed that 72% of them had felt the need for dental treatment. Conclusion: The study showed that risk factors such as habits, systemic diseases, and self-perceived oral health played a significant role in tooth loss. Brushing type, method, and material used for cleaning were some other factors that influenced tooth loss.

Thermomechanical Properties and Glass Dynamics of Polymer-Tethered Colloidal Particles and Films.

Polymer-tethered colloidal particles (aka “particle brush materials”) have attracted interest as a platform for innovative material technologies and as a model system to elucidate glass formation in complex structured media. In this contribution, Brillouin light scattering is used to sequentially evaluate the role of brush architecture on the dynamical properties of brush particles in both the individual and assembled (film) state. In the former state, the analysis reveals that brush–brush interactions as well as global chain relaxation sensitively depend on grafting density; i.e., more polymer-like behavior is observed in sparse brush systems. This is interpreted to be a consequence of more extensive chain entanglement. In contrast, the local relaxation of films does not depend on grafting density. The results highlight that relaxation processes in particle brush-based materials span a wider range of time and length scales as compared to linear chain polymers. Differentiation between relaxation on local and global scale is necessary to reveal the influence of molecular structure and connectivity on the aging behavior of these complex systems.

Preliminary Assessment of Risk Factors for Tooth Wear

Abstract Background: Epidemiological studies have reported an increasing prevalence of tooth wear, and general dental practitioners see a greater number of patients seeking treatment with worn dentition. Improper oral hygiene, unhealthy habits, occupational hazards, and potentially erosive processed foods seem to play a major role in the non-carious loss of dental hard tissue. The aim of this study is to assess the factors and cofactors that may play a major role in the genesis of dental attrition, dental abrasion, and, especially, dental erosion. Material and methods: Seventy-nine consecutive patients, aged between 17 and 78 years, have enrolled in our study, completing a questionnaire regarding chronic illnesses, eating habits, and dental hygiene, followed by a dental clinical examination. Results: The male-female ratio was 1.4:1, with a mean age of 35.6 years. Forty-four (55.7%) patients presented objective signs of tooth wear. Regarding oral hygiene habits, the use of a hard toothbrush is linked to increased tooth wear, while brushing in a circular motion seems to be the least abrasive. We found a considerable prevalence of bruxism (19%), which led to severe generalized attrition in almost half of such patients. The most popular drinks with erosive potential were coffee (58.2%), soft drinks (57%), and tea (24.1%), and extrinsic erosion was more frequent in patients younger than 30 years. Understandably, physiological tooth wear was more common in older patients. The questionnaire revealed that over 60% of patients have inaccurate knowledge of tooth wear. Conclusions: Tooth wear is partially a progressive physiological process. Unfortunately, we see it increasing in younger patients due to pathological influencing factors. These include improper tooth brushing technique and materials, bruxism, dental prosthesis, dietary habits. Primordial and primary prevention is the key to reducing morbidity, health education being an essential part of it.

Structure zone diagram and particle incorporation of nickel brush plated composite coatings

This work studies the deposition of aluminium-incorporated nickel coatings by brush electroplating, focusing on the electroplating setup and processing parameters. The setup was optimised in order to increase the volume of particle incorporation. The optimised design focused on increasing the plating solution flow to avoid sedimentation, and as a result the particle transport experienced a three-fold increase when compared with the traditional setup. The influence of bath load, current density and the brush material used was investigated. Both current density and brush material have a significant impact on the morphology and composition of the coatings. Higher current densities and non-abrasive brushes produce rough, particle-rich samples. Different combinations of these two parameters influence the surface characteristics differently, as illustrated in a Structure Zone Diagram. Finally, surfaces featuring crevices and peaks incorporate between 3.5 and 20 times more particles than smoother coatings. The presence of such features has been quantified using average surface roughness Ra and Abbott-Firestone curves. The combination of optimised setup and rough surface increased the particle content of the composite to 28 at.%.

Accelerated testbed for studying the wear, optical and electrical characteristics of dry cleaned PV solar panels

A testbed was designed and built for studying the impact of brush-based dry cleaning on glass samples and photovoltaic (PV) solar panels. A sand deposition shaking system was integrated into the testbed to continuously deposit dust on the brushed surfaces simulating the real environmental dust conditions for a 20-year equivalent time of cleaning. The cleaning efficiency was evaluated for different types of brush materials of nylon, cloth and silicon rubber foam. In this piece of work, the focus was mainly on brushing real solar panels, which already have anti-reflective coating applied to measure the output short circuit current, which is the IV characteristics dominant factor. While some materials had a notable impact on the solar panels, no permanent or significant negative impact was found to affect the solar panels as a result of the brush-based dry cleaning with the other materials. In fact, an enhancement in the maximum power output of solar panels cleaned with silicone rubber was around 1% from the unbrushed initial power output, which could be attributed to the created surface geometry. The silicon rubber foam — a novel brush material, with no previous research literature describing its use as a brush material — provides a low cost material and allows for a simple brush design, which could reduce the cost of the brush used in robotic cleaning systems, while providing highly effective, nonabrasive cleaning.

Surface affinity role in graphoepitaxy of lamellar block copolymers

Overcoming the optical limitations of 193-nm immersion lithography can be achieved using directed self-assembly (DSA) of block-copolymers (BCPs) as a low-cost and versatile complementary technique. The goal of this paper is to investigate the potential of DSA to address line and space (L/S) high-resolution patterning by performing the density multiplication of lines with the graphoepitaxy approach. As surface affinity is a key parameter in self-assembly, three variations, or “flavors,” of DSA template affinity are investigated regarding several success criteria such as morphology control or defectivity. More precisely, both the methodology to register DSA defects and the impact of process parameters on defectivity are detailed. Using the 300-mm pilot line available in LETI and Arkema’s advanced materials, we investigate process optimization of DSA line/space patterning of a 38-nm period lamellar PS-b-PMMA BCP (L38). Our integration scheme is based on BCP self-assembly inside organic hard mask guiding patterns obtained using 193i-nm lithography. Defect analysis coupled with the fine tuning of process parameters (annealing, brush material) provided the optimum conditions for the L38 self-assembly. Using such conditions, DSA using the three affinity flavors is investigated by means of SEM top-view and cross-section review. Lithographic performances of one selected flavor are then evaluated with the comparison of process windows function of either commensurability, morphology, or roughness. This work is meant as a guideline for the graphoepitaxy optimization of materials and process parameters on a 300-mm platform.

Diagnostic accuracy of endoscopic brush cytology in malignancies of upper gastrointestinal tract: A prospective study of 251 patients in North India

To find the spectrum and frequency of upper gastrointestinal malignancies and diagnostic accuracy of endoscopic brush cytology in their diagnosis. This study was a prospective study carried out on 251 patients over 1-year in the Department of Pathology. Brushing material was smeared directly on to at least two clean glass slides and was stained with May-Grunwald-Giemsa stain. The endoscopic biopsies were examined grossly and were fixed in 10% formalin, processed, and stained with hematoxylin and eosin stain. The age range of the patients varied from 8 to 90 years, with the mean being 56 years. Male to female ratio was 2.5:1. On brush cytology, out of 251 cases, 110 had benign lesions and 97 had malignant lesions. Forty-four samples were considered suspicious of malignancy. On histopathology, benign lesions were present in 105 patients while malignant lesions were seen in 139 patients. In seven cases, results were inconclusive due to inadequate/superficial biopsy. Statistical analysis revealed the overall sensitivity of upper gastrointestinal brush cytology as 83.45% and specificity 80.95%. The accuracy of brush cytology came out to be 82.37% in upper gastrointestinal tract. Brush cytology is a reliable, safe, inexpensive, and rapid method of diagnosing upper gastrointestinal lesions. Although endoscopic biopsies are established gold standard for diagnosing gastrointestinal malignancy, use of both biopsy and brushing together increases the diagnostic accuracy.

Tailoring structure formation and mechanical properties of particle brush solids via homopolymer addition.

Recent progress in the area of surface-initiated controlled radical polymerization (SI-CRP) has enabled the synthesis of polymer-grafted colloids with precise control over the architecture of grafted chains. The resulting 'particle brush materials' are of interest both from a fundamental as well as applied perspective because structural frustrations (associated with the tethering of chains to a curved surface) imply a sensitive dependence of the interactions between brush particles on the architecture of surface-tethered chains that offers new opportunities to design hybrid materials with novel functionalities. An important prerequisite for establishing structure-property relations in particle brush materials is to understand the role of homopolymer impurities that form, for example, by thermal self-initiation. This contribution presents a detailed discussion of the role of homopolymer additives on the structure and mechanical properties of particle brush materials. The results suggest that the dissolution of homopolymer fillers follows a two-step mechanism comprised of the initial segregation of homopolymer to the interstitial regions within the array and the subsequent swelling of the particle brush (depending on the respective degree of polymerization of brush and linear chains). Addition of even small amounts of homopolymer is found to significantly increase the fracture toughness of particle brush assembly structures. The increased resistance to failure could enable the synthesis of robust colloidal crystal type materials that can be processed into complex shapes using 'classical' polymer forming techniques such as molding or extrusion.

Processing fragile matter: effect of polymer graft modification on the mechanical properties and processibility of (nano-) particulate solids.

The effect of polymer modification on the deformation characteristics and processibility of particle assembly structures is analyzed as a function of particle size and degree of polymerization of surface-tethered chains. A pronounced increase of the fracture toughness (by approximately one order of magnitude) is observed as the degree of polymerization exceeds a threshold value that increases with particle size. The threshold value is interpreted as being related to the transition of tethered chains from stretched-to-relaxed conformation (and the associated entanglement of tethered chains) and agrees with predictions from scaling theory. The increase in toughness is reduced with increasing particle size - this effect is rationalized as a consequence of the decrease of entanglement density with increasing dimension of interstitial (void) space in particle array structures. The increased fracture toughness of particle brush materials (with sufficient degree of polymerization of tethered chains) enables the fabrication of ordered colloidal films and even complex 3D shapes by scalable polymer processing techniques, such as spin coating and micromolding. The results, therefore, suggest new opportunities for the processing of colloidal material systems that could find application in the economical fabrication of functional components or systems compromised of colloidal materials.

Aspects regarding the tribological evaluation of sintered composites obtained from mixture of copper with carbon fibers

This paper presents a study of the tribological properties of sintered composite materials made from combination of copper with short carbon fibers. Sintered composite materials are more effective if refer to specific properties per unit volume compared to conventional isotropic materials. Potential advantages of copper - carbon composite materials are: high resistance to breakage and high value ratios strength/density; resistance to high temperatures; low density and high resistance to wear; low or high friction coefficient. The sintered composite materials used in this research work are obtained combining different percentages of copper with short carbon fibres with iron and lead in order to investigate the variation of the friction behaviour. Varying the percentage of copper from 92,2% to 97,6% and the percentage of short carbon fibres from 7,8% to 2,4%, five different composite materials are obtained and tested. Friction tests are carried out, at room temperature, in dry conditions, on a pin-on-disc machine. The friction coefficient was measured using abrasive discs made from steel 4340 having the average hardness of 40 HRC, and sliding velocity of 0,6 m/sec. The main objective of this research work it was to identify a combination of materials with improved friction behaviour. The experimental results revealed that the force applied on the specimen during the tests, is playing a very important role regarding friction coefficient and also the wearing speed. Graphite particles are conveyed consistently inside the net, enhancing scraped spot safety and voltage drop over normal composite material. The static tests demonstrated that this new kind of sintered composite material has preferable electrical execution over previous brush material in the same conditions, and the element tests demonstrated that the temperature climb is not enormous when the brush with this new composite material is exchanged on with huge current and the surface scraped spot is littler amid sliding. The new method of obtained sintered composites, using high-energy and high speed is adequate for production of tribological parts.

Synthesis and Quantitative Characterization of Novel Copper-Graphite Composite Materials for Use as Electrical Sliding Contacts

Abstract This work presents quantitative microstructures and triboelectric properties of melt-infiltrated copper-graphite composites which are characterized by a specific structural composition. It compares them with commercially available carbon brush material. The structural design requires the synthesis of open porous graphite preforms. This work reports on advances in the powder preparation and the production of composites by means of direct squeeze casting. A specially developed tribo-electric testing device is presented. It is used to simultaneously test tribological, thermal, as well as electrical influences.

COREL PAINTER: FOR THE WHOLE SKETCHING AND COLORING

Corel Painter is a raster-based digital art application created to simulate as accurately as possible the appearance and behavior of traditional media associated with drawing, painting, and printmaking. It is intended to be used in real-time by professional digital artists as a functional creative tool. The current version is Painter X3, released on July 2013.Corel Painter emulates the visual characteristics of traditional media, such as oil paint, pastel sticks, air brush, charcoal, felt pens, and other traditional artists' materials on various textured surfaces. Many of these emulated media types work with the advanced features of Wacom tablets. For instance, the airbrush tool in Painter responds to pressure as well as tilt, velocity and rotation. Corel History:

Tribological behavior of brass fiber brush against copper, brass, coin-silver and steel

The brass fiber brushes with various packing fractions were prepared by the method of filling and dissolving aluminum fibers. The compression tests of brass fiber brushes and brass block were conducted. The tribological behavior of the selected brass fiber brush of 23% packing fraction sliding against the copper, brass, coin-silver and steel discs was investigated. The microstructure, worn surface and wear debris of the brush and counterface materials were observed and analyzed to investigate the involved wear mechanisms. The compressibility of brass fiber brushes increases with the increase of packing fraction, and is much higher than the brass block. The brush against the four discs exhibits significantly high friction coefficient values range from 0.8 to 1.0 but the curves are fairly smooth. The brass fiber brush sliding against copper and brass discs experiences severe adhesive wear and gives a high wear rate compared with that against coin-silver and steel discs. The wear behavior of the brass fiber brush strongly depends on the counterface materials under dry sliding condition. The differences of the friction and wear mechanisms between fiber brushes and solid brushes were also discussed.

Role of Polymer Graft Architecture on the Acoustic Eigenmode Formation in Densely Polymer-Tethered Colloidal Particles.

The concurrent evaluation of the vibration eigenfrequencies in densely polymer-tethered particle systems ("particle brushes") by Brillouin light scattering and elastodynamic theory reveals a distinctive change of acoustic eigenmode formation associated with polymer graft modification of colloidal particles. The eigenfrequencies of particle brushes reveal a characteristic red-shift compared to uniform core-shell particles that can only be rationalized by assuming imperfect boundary conditions and anisotropic elastic properties of the graft layer. The distinct characteristics of vibration modes in particle brush materials provide direct evidence for the implications of chain confinement on the nanomechanical properties of tethered chains. The results highlight a rich and hitherto unexplored parameter-space for controlling properties and interactions in particle-brush based systems that could spur the development of hybrid materials with novel functionalities.

Effect of Thermal Self-Initiation on the Synthesis, Composition, and Properties of Particle Brush Materials

Surface-initiated atom transfer radical polymerization (SI-ATRP) has emerged as a powerful tool to synthesize polymer-tethered particles (here called particle brushes) that can self-assemble into hybrid materials with well-defined microstructure, morphology, and enhanced mechanical properties or optical transparency, as compared to binary particle/polymer nanocomposite materials. However, side reactions—such as the thermal self-initiation (TSI) of some monomers, such as styrene, during the polymerization—can result in the formation of varying amounts of homopolystyrene, in addition to particle brushes. The presence of homopolystyrene impurity reduces the predictability of properties and impedes the interpretation of structure–property relations in particle brush materials. This contribution presents a systematic evaluation of the formation of TSI homopolystyrene and its implications on the properties of polystyrene-tethered silica based particle brush materials. Kinetic and molecular weight studies reveal that the fraction of untethered chains generated by TSI depends on reaction conditions and increases with the degree of polymerization of surface-tethered chains. The presence of homopolystyrene results not only in a decrease of the softening temperature but also in an increase of ductility and toughness of particle brush solids. Structural analysis of particle brush assemblies admixed with small particle tracer inclusions suggests that the increase in ductility is related to the preferential segregation of the polystyrene impurity within the corner regions of the Wigner–Seitz cell of the particle brush array.

Study of Preparation Technology and Properties of Silver Based Electric Brush Materials

This paper introduced the preparation technology and properties of Ag-MoS2, silver-graphite and AgPd/BZn series silver based brush materials, the existing problems on materials and preparation technology were also analyzed and studied. Materials with the best performance were filtered out through selection of added elements. Influence of added elements and the material properties were analyzed, and the brush material suitable for different application requirements were summarized by analysis the experimental data; so new ideas for the further development of silver matrix brush materials with excellent properties were propounded.

Surface-Initiated Polymerization as an Enabling Tool for Multifunctional (Nano-)Engineered Hybrid Materials

Surface-initiated atom transfer radical polymerization (SI-ATRP) has become an indispensable tool for engineering the structure and properties of polymer/inorganic and polymer/organic interfaces. This article describes the progress and challenges that are associated with the application of SI-ATRP to precisely control the molecular characteristics of polymer chains tethered to nanoparticle surfaces and explores the properties and potential applications of the resulting particle brush materials. Even for the conceptually most “simple” particle brush systems—that is, spherical particles uniformly grafted with amorphous nonpolar polymers—the complex superposition of interactions as well as time- and length-scales related to particle core and tethered chains provides a rich and largely unexplored parameter space for the design of novel functional materials. The application of the particle brush approach to the development of materials for applications ranging from photonic inks and paints to advanced high “k” dielectrics for energy storage and advanced nanocomposite materials with improved optical, mechanical, or transport characteristics is discussed.

Effect of Polymer-Graft Modification on the Order Formation in Particle Assembly Structures

The propensity of particle brush materials to form long-ranged ordered assembly structures is shown to sensitively depend on the brush architecture (i.e., the particle radius as well as molecular weight and grafting density of surface-bound chains). In the limit of stretched chain conformations of surface-grafted chains the formation of regular particle array structures is observed and interpreted as a consequence of hard-sphere-type interactions between polymer-grafted particles. As the degree of polymerization of surface-grafted chains increases beyond a threshold value, a reduction of the structural regularity is observed that is rationalized with the increased volume occupied by relaxed polymer segments. The capacity of polymer grafts to increase or decrease order in particle brush assembly structures is interpreted on the basis of a mean-field scaling model, and "design criteria" are developed to help guide the future synthesis of colloidal systems that are capable of forming mechanically robust yet ordered assembly structures.

Effect of sintering temperature on the preparation of Cu–Ti3SiC2 metal matrix composite

Ti3SiC2 has the potential to replace graphite as reinforcing particles in Cu matrix composites for applications in brush, electrical contacts and electrode materials. In this paper the fabrication of Cu–Ti3SiC2 metal matrix composites prepared by warm compaction powder metallurgy forming and spark plasma sintering (SPS) was studied. The stability of Ti3SiC2 at different sintering temperatures was also studied. The present experimental results indicate that the reinforcing particles in Cu–Ti3SiC2 composites are not stable at and above 800°C. The decomposition of Ti3SiC2 will lead to the formation of TiC and/or other carbides and TiSi2. If purity is the major concern, the processing and servicing temperatures of the Cu–Ti3SiC2 composite should be limited to 750°C or lower. The composites prepared by warm compaction forming and SPS sintering at 750°C have lower density when compared with the composites prepared by SPS sintering at 950°C, but their electrical resistivity values are very close to each other and even lower.