Acrylic Pieces Research Articles

The Comparison between Black Cumin Extract and Betel Leaf Extract As Antifungal Potential to Candida Albicans on Acrylic Resin Denture Base

Porosity in acrylic resin denture base causes a rough surface and can absorb fluid, leading to plaque. Candida albicans can stick to a plaque on the denture base and engender denture stomatitis. Denture base submersion has to be carried out in traditional plant solutions to prevent denture stomatitis. Traditional plants such as black cumin and betel leaf are considered to have anti-fungal properties. This study aims to identify the comparison of antifungal properties between black cumin and betel leaf extract to Candida albicans on the acrylic resin denture base. This study is an experimental laboratory. Treatment group 1 used aquadest as a control negative, treatment group 2 used a black cumin extract with a concentration of 0.25%, while treatment group 3 used betel leaf extract with a concentrate of 50%. In every group, 9 acrylic resin pieces were soaked for 8 hours. The colony calculation was then conducted and analyzed using the Mann-Whitney test to compare the average difference level between the two tested groups. There was no significant difference level among a total colony of Candida albicans in the treatment group with a concentration of 0.25% black cumin and the treatment group with a 50% concentration of betel leaf. The result showed that the black cumin extract is no more effective in hindering the growth of Candida albicans on the acrylic resin denture base than betel leaf extract.

Management of large inflammatory dentigerous cysts adapted to the general condition of the patient: Two case reports.

Dentigerous cysts may be of developmental or inflammatory origin. The latter occur in unerupted permanent teeth as a result of inflammation from a preceding non-vital primary tooth or from another source spreading to involve the tooth follicle. This report presents two clinical cases of children with dentigerous cysts of inflammatory origin. Case 1 is a healthy boy (7 years 11 months) referred for a large cystic cavity in the right mandibular premolar region. Extraction of 84 and 85 and marsupialization of the cyst were performed under nitrous sedation. A removable appliance with an acrylic piece fitted into the socket was applied on the same occasion. The in-socket piece was progressively reduced as the cystic cavity was shrinking. After a 20-month follow-up, 44 and 45 are sound and correctly erupted and 46 remains unaffected. Case 2 is an autistic girl (10 years 9 months) with bilateral large odontogenic cysts enclosing the crowns of 35 and 45. Extractions of 75, 85 were performed under general anesthesia, leaving large bone defects. Given the limited compliance of the patient under common dental office circumstances, no appliance was used. Thirteen months after extraction, 35 and 45 are sound, fully erupted and no visible mesial drifting of 36 and 46 occurred. In conclusion, conservative treatment of large inflammatory dentigerous cysts in children gives good results with minimal intervention, ensures physiologic development of teeth and proper bone healing. The general condition of the patient can influence treatment choice. Patients must be followed up until eruption of the displaced permanent teeth and bony consolidation of the cyst.

A Simple Way to Demonstrate Fluorescent Image by Employing a Conventional Microscope and Transparent Colored Acrylic Pieces

In this study, we describe a method to employ a conventional compound light microscope, usually available in laboratories, to obtain fluorescence. In particular, two pieces of colored acrylic plastic were utilized to assist the microscope in filter performance. We also attempted to examine the applicability of the setup by staining onion cells with highlighter ink. This activity is intended to serve as an experiment for life sciences courses using physics-based methods in a biological context. This setup has the advantages of ease of use and low cost.

Open source 3D printable replacement parts for the WHO insecticide susceptibility bioassay system

BackgroundMalaria vector control and research rely heavily on monitoring mosquito populations for the development of resistance to public health insecticides. One standard method for determining resistance in adult mosquito populations is the World Health Organization test (WHO bioassay). The WHO bioassay kit consists of several acrylic pieces that are assembled into a unit. Parts of the kit commonly break, reducing the capacity of insectaries to carry out resistance profiling. Since there is at present only a single supplier for the test kits, replacement parts can be hard to procure in a timely fashion.MethodsUsing computer-aided design software and widely available polylactic acid (PLA) filament as a printing material, we 3D designed and printed replacement parts for the WHO bioassay system. We conducted a comparison experiment between original WHO bioassay kits and 3D printed kits to assess congruence between results. The comparison experiment was performed on two Kenyan laboratory strains of Anopheles gambiae (s.s.), Kilifi and Mbita. Studentʼs t-tests were used to assess significant differences between tube types. Finally, we exposed the PLA filament to common solutions used with the bioassay kit.ResultsWe were able to design and print functional replacements for each piece of the WHO bioassay kit. Replacement parts are functionally identical to and interchangeable with original WHO bioassay parts. We note no significant difference in mortality results obtained from PLA printed tubes and WHO acrylic tubes. Additionally, we observed no degradation of PLA in response to prolonged exposure times of commonly used cleaning solutions.ConclusionsOur designs can be used to produce replacement parts for the WHO bioassay kit in any facility with a 3D printer, which are becoming increasingly widespread. 3D printing technologies can affordably and rapidly address equipment shortages and be used to develop bespoke equipment in laboratories.

The Effectiveness of Nigella Sativa Alcoholic Extract on the Inhibition of Candida Albicans Colonization and Formation of Plaque on Acrylic Denture Plates: an In Vitro Study.

Statement of the Problem: Due to growing concerns on complications of chemical drugs, the use of herbal extracts has been considered as denture cleaning solutions. Purpose: The aim of this study was to evaluate the in-vitro effects of Nigella sativa on the cleansing of the formation of Candida albicans plaque on the acrylic resin pieces. Materials and Method: In this experimental study, 30 pieces of acrylic resin were contaminated by Candida albicans suspension. Then, the acrylic pieces were randomly divided into six groups and treated with 0.2, 0.4, 20, and 200 mg/ml of Nigella sativa, 100,000 units of nystatin (positive control), and distilled water (negative control) for 8 hours. At the end of the exposure period of the drugs, the rinse solution from acrylic pieces was cultured in Sabouraud Dextrose Agar and the average of the colonies from each group was compared. Results: The average number of colonies obtained at concentrations of 0.2, 0.4, 20, and 200 mg/ml of Nigella sativa were 122.6, 117.8, 73.4, and 14.4 colonies, respectively, as compared to distilled water (141.6) and nystatin (0) that had a significant difference (p< 0.001). Conclusion: Nigella sativa extract at definite concentration is capable of clearing dental prosthesis, but compared to nystatin, it is weaker. However, due to the indirect immune-regulatory effects of Nigella sativa, it is suggested that other studies be conducted to investigate the therapeutic properties of Nigella sativa from the aspects of antimicrobial, anti-inflammatory, and oral ulcer healing in candida oral lesions.

Agarose-based Tissue Mimicking Optical Phantoms for Diffuse Reflectance Spectroscopy.

This protocol describes how to make agarose-based tissue-mimicking phantoms and demonstrates how to determine their optical properties using a conventional optical system with an integrating sphere. Measuring systems for the acquisition of the diffuse reflectance and total transmittance spectra are constructed with a broadband white light source, a light guide, an achromatic lens, an integrating sphere, a sample holder, an optical fiber probe, and a multi-channel spectrometer. An acrylic mold consisting of two rectangular acrylic pieces and a U-shaped acrylic piece is constructed to create an epidermal phantom and a dermal phantom with whole blood. The application of a sodium dithionite (Na2S2O4) solution to the dermal phantom enables the researcher to deoxygenate hemoglobin in red blood cells distributed in the dermal phantom. The inverse Monte Carlo simulation with the diffuse reflectance and total transmittance spectra measured by a spectrometer with an integrating sphere is performed to determine the absorption coefficient spectrum µa(λ) and the reduced scattering coefficient spectrum µs'(λ) of each layer phantom. A two-layered phantom mimicking the diffuse reflectance of human skin tissue is also demonstrated by piling up the epidermal phantom on the dermal phantom.

A simple magic cup to inject excitement and curiosity in physics

This article highlights a simple demonstration kit that can be easily fabricated in Design & Technology (D&T) workshops to inject excitement and curiosity into students’ learning of physics concepts such as density and optics. Using an ice cream cup from a fast food restaurant and a transparent circular acrylic piece, students can be guided to make a ‘magic’ cup, while at the same time get inquisitive about the physics behind the magic. The project highlights a way of linking physics to D&T in a feasible manner which can motivate and engage students.

Refractive index and its impact on pseudophakic dysphotopsia.

PurposeIt has been shown that the biggest dissatisfier for uncomplicated cataract surgery patients is pseudophakic dysphotopsia (PD). While edge design of an intraocular lens (IOL) impacts this problem, refractive index is still controversial as to its impact. This retrospective cohort study was designed to determine the role of increasing refractive index in PD.Patients and methodsThis study was conducted at the John A. Moran Eye Center, University of Utah, USA. A retrospective chart review identified patients who received one of two hydrophobic acrylic single piece IOLs (AcrySof WF SP [SN60WF] or Tecnis SP [ZCB00]), which differed mainly by refractive index (1.55 versus 1.47). Eighty-seven patients who had received implantation of a one-piece hydrophobic acrylic IOL were enrolled. Patients were included if the surgery had been uncomplicated and took place at least a year before study participation. All eligible patients had 20/20 best corrected vision, without any disease known to impact visual quality. In addition to conducting a record review, the enrolled patients were surveyed for PD, using a modified National Eye Institute Visual Function questionnaire, as well as for overall satisfaction with visual quality.ResultsStatistical analysis demonstrated no difference between the two cohorts regarding PD, general visual function, and overall visual satisfaction.ConclusionThe study suggests that with the two IOLs assessed, increasing the refractive index does not increase incidence of PD or decrease overall visual satisfaction.

Hologravure as a computer-generated and laser engraved scratch hologram

We presented “hologravure” as the generalization of a scratch hologram, generated by computer from a three-dimensional (3D) model by using an appropriate software, and laser-drawing with a conventional engraver-laser system. For making this type of computer-generated hologram, neither diffractive optics, nor mask pattern or photo-reduction of a transparency onto a high resolution film plate is needed. The shape of a 3D virtual object is encoded in a two-dimensional (2D) multiple circular-scratch drawing. A computer program was created for generating the holograms. Hologravures representing several 3D models are engraved on different materials, and the quality of the lines traced by the CO 2 laser is considered. Sheets of acrylic, polycarbonate, glass and thermo-resistant pieces of acetate were tested. Reconstructed images of all this computer-generated and laser engraved holograms and also of computer assisted and hand-drawn scratch holograms, synthesized by means of the same software are shown.

A Practical Method for Fatigue Crack Initiation Detection Using an Ion-Sputtered Film

The development of fatigue in a machine element can be divided into the fatigue crack initiation stage and the crack growth stage. The effects of the surface conditions, such as roughness and surface qualities, on the fatigue strength are considered to be restricted to the fatigue crack initiation stage. Thus, these effects can be evaluated exactly by the investigation on the fatigue crack initiation life. In this research a practical method is presented for detecting fatigue crack initiation during fatigue tests using an ion-sputtered film. Ion-sputtered films were formed on acrylic and steel test pieces having a specially designed round notch. Three-point bending fatigue tests were performed and the instants of fatigue crack initiation on the notched surface of both acrylic and steel test pieces during the tests were identified clearly; thus the fatigue crack initiation life can also be determined experimentally using the presented method. In addition, since the system used to measure the electric resistance of the film, which indicates the crack initiation, is extremely simple, that is, it consists of a variable resistor, a DC power source, and a data recorder, this method is considered very practical for monitoring crack initiation.

B107 タービンシュラウドの傾斜インピンジメント冷却に関する実験的研究

Very effective cooling methods have been required for high-temperature gas turbines. Reduction of cooling air also contributes to the improvement of jet engine performance, because the cooling air is bled from compressor of jet engine. Therefore, from this point of view, Multiple inclined impingement cooling for turbine shroud cooling has been invented by IHI, JAXA and authors' group. This cooling structure realizes 50% reduction of cooling air compared with conventional one maintaining same cooling efficiency. However detailed internal cooling behavior has not been clarified. This study is one of the researches in collaboration with IET, JAXA and us. The main purpose is to clarify the cooling behavior by Particle Image Velocimetry (PIV) and heat transfer measurement on the impingement wall by IR camera. In this paper, we describe the results of PIV for 4 types of acrylic test pieces (impingement angle=90°, 45°, 35°, 25°). The characteristics of time-averaged velocity, turbulence intensity and pressure drop were considered.

2129 反応度投入事象模擬試験用の X 線ボイド率計の開発

During a Reactivity Initiated Accident (RIA) in a boiling water reactor (BWR), rapid power increase might be occurred. In order to evaluate fuel rod integrity properly, it is very important to understand the void fraction behavior under rapid power increase. In this study, test section and X-ray void meter for RIA tests were developed. The test section was composed of 3×3bundle heater, upper and lower electrodes, channel box and pressure vessel. The direct heaters were used for 3×3 bundle in order to simulate rapid power increase during RIA event. Sampling rate for the X-ray void meter was 5 ms. Measuring axial length for the meter was 100mm. The accuracy of the developed void measurement system was verified by acrylic test piece simulating the two-phase flow. As the verification test result, the accuracy of the void meter was about 2%.

A new device for standardized intraoral projection: An observation of radiographic changes after root planing

The purposes of this study were to evaluate the geometric and densitometric reproducibility of a newly developed standardized X-ray system and to examine the radiographic changes after scaling/root planing as shown by this device. The system was comprised of three parts: an acrylic bite piece for the individual patient, an aluminum wedge-equipped holder, and a holder-connecting device. The experiment was performed at 32 sites of premolar and molar areas in 19 patients. Radiographs were retaken 6 weeks after scaling/root planing and the reproducibility and radiographic changes were examined. The vertical and horizontal geometric reproducibility of the system at 32 sites in 19 patients were 1.0% and 1.8%, respectively. Of 351 scaled sites, 39 (11.1%) exhibited bone regeneration, and 6 (1.7%) exhibited bone loss. These results indicate that the newly developed system has high accuracy and clinical usefulness. Early bone remodeling can be observed radiographically after 6 weeks with our standardized X-ray system.

Personal Identification by DNA Analysis of Samples from Dental Prostheses Made of Acrylic Resin.

The procedures and possibilities for personal identification by DNA analysis of samples from dental prostheses made of acrylic resin were investigated. Acrylic resin pieces dipped in whole saliva for a moment, dried in air and left for at least two months at room temperature retained saliva stains that could be used as materials for DNA analysis for personal identification. The amounts of DNA extracted from 0.5×0.5×0.1cm resin pieces prepared from 55 resin prostheses used by the patients ranged from 35.7ng to 1.52μg and were significantly different among the samples. The amounts of extractable DNA did not correlate with the period of time the prostheses were left at room temperature or the period of time they were used in the oral cavity. Sex determination by amplification of segments of the amelogenin gene and typing of the 184bp fragment in the D4S43 locus was possible from all of the extracted DNA. Resin prostheses used in the oral cavity and left at room temperature for as long as approximately 200 days could be used for DNA extraction followed by DNA analysis. The present results provide a procedure that can be used from sampling of DNA from resin prostheses used in the oral cavity to typing by DNA analysis.

The influence of morphological variation on Candida albicans adhesion to denture acrylic in vitro

Using denture acrylic pieces coated with either whole human stimulated saliva or oral streptococci, the binding ability of three different Candida albicans strains was investigated. The C. albicans strains include a clinical isolate with the commonly observed, smooth, round colonial morphology (strain 613p), a morphological variant spontaneously derived from the clinical isolate strain 613p (strain 613mlBK) and a clinical isolate from an oral lesion that was also a morphological variant upon primary isolation (strain 228). Levels of adhesion to the acrylic pieces were determined radiometrically using C. albicans cells metabolically labelled with [ 35S]-methionine. Whole stimulated saliva significantly increased the binding of all strains compared to uncoated acrylic. However, the level of binding of strain 613p to saliva-coated acrylic was significantly greater than the levels observed for the morphological variant strain 613mlBK. Coating acrylic pieces with either Streptococcus sanguis NCTC 10904, Strep. mutans GS-5 or Strep, sobrinus ATCC 27352 instead of saliva resulted in significantly greater binding by strain 613p compared to uncoated acrylic. Pre-coating the acrylic with the oral streptococci did not significantly increase the binding of morphological variant strains 613mlBK and 228 compared to uncoated acrylic. In general, preincubation of adherent streptococci with sucrose to induce the synthesis of extracellular carbohydrate polymers did not significantly increase the binding levels of the C. albicans strains above those observed using streptococci in buffer alone. Compared to its parental strain 613p, morphological variant strain 613mlBK adhered poorly to denture acrylic coated with either salivary constituents or oral streptococci, while strain 228 adhered to the same substrates at an intermediate level. Furthermore, physical disaggregation of clusters of the morphological variant strain 613mlBK did not appear to increase its binding capacity to saliva-coated denture acrylic. The effect of whole stimulated saliva on the adherence of C. albicans 613p to a variety of plastic substrates in addition to denture acrylic was examined. Overall, saliva pre-coating of the various plastics promoted C. albicans 613p adhesion. The adhesion of strain 613p to denture acrylic coated with whole stimulated saliva from each of five different donors or with parotid and submandibular/sublingual saliva from each of two donors was also examined. Regardless of donor, a coating of whole stimulated saliva significantly increased the binding of strain 613p to denture acrylic compared to uncoated acrylic. In addition, a coating of parotid saliva significantly increased the binding of strain 613p to denture acrylic compared to submandibular/sublingual saliva.

Inhibition of adherence of Candida albicans to acrylic by a chitin derivative.

The purpose of this study was to assess the effect of a chitin derivative (CSE) on the adherence of Candida albicans to acrylic. Fungal adherence to acrylic dentures is considered an essential step in the development of denture stomatitis. Adherence of C. albicans to acrylic pieces (5 x 5mm) was assessed microscopically using a calibrated ocular objective and expressed as number of adherent yeasts/mm2 of acrylic. CSE was prepared from commercial chitin (crab shell) and from chitin isolated from C. albicans blastospores. The effect of both CSE types on the adherence of C. albicans to acrylic was examined in two experimental systems: CSE present during the adherence assay and acrylic pieces pretreated with CSE prior to the assay. Both CSE types exerted a significant inhibitory effect when tested in the two experimental systems. These findings are significant for possible prevention of denture stomatitis.

Output switch for a megavolt electron beam generator

An improved gas output switch for a 12 Ω, 1.2 MV electron beam generator has been developed. The previous design used a cast epoxy switch housing with an embedded field shaper electrode. The original switch design was difficult to fabricate without defects in the casting, and several replacements failed during operation. The new design employs machined acrylic pieces instead of cast epoxy, and a glycol cavity surrounds the field shaper. Electric fields around the field shaper are therefore considerably lower. The present switch has demonstrated greater reliability and superior performance.

The Effect of pH on Adhesion and Hyphal Formation by Strains ofCandida albicans

The adhesion of five strains of Candida albicans to smooth acrylic was compared. Early exponential phase cells were suspended in buffers at pH 2.6-7.3 and allowed to adhere to acrylic pieces. Attachment was measured in terms of percentage area coverage of a microscopic field covered by cells, using automated image analysis. The strain that adhered in the highest numbers also adhered best at pH 7.3; however, for the other strains pH did not significantly influence adhesion. Two strains, isolated from cases of denture stomatitis, produced hyphae, particularly at lower pH values, in buffer without any carbon or nitrogen sources. For two ‘carrier’ strains hyphal formation was minimal. The fifth strain studied did not produce hyphae although it had been isolated from a case of denture stomatitis. A strain from each of the above categories was selected and the adhesion to buccal epithelial cells (BEC) was measured, at pH 7.3, 6.0 and 2.6, using a visual microscopic count. All strains were capable of adhering at all the pH values studied although the adhesion was low (1-9 Candida cells per BEC). The adhesion of the strains to BEC was increased when stationary phase cells were used compared to early exponential phase cells. Strain GDH 2346 produced hyphae at pH 2.6. All strains gave a very low cell surface hydrophobicity which could not be related to the ability of strains to adhere to either acrylic or BEC. Keywords: pH; Adhesion; Candida albicans ; Buccal epithelial cells; Acrylic; Denture stomatitis.

A rudimentary touch input device for visual displays

An inexpensive and simple device that can be fitted to existing computer visual display units and that gives a limited touch input capability is described. Small transparent acrylic pieces are held in front of the CRT by stiff wires attached to microswitches. The device has proved useful in the provision of computer-assisted instruction for young children.

Practical variations of cranioplasty

Indications for the repair of skull defects may be brain protection, cosmetic and psychologic. As there is no panacea for all skull deformities the best method must be determined for each case depending on the size and type of defect as well as the age and health of the patient. Whether the repair be with metal, plastic or bone, closure of the scalp over the area must be achieved without tension. Young active adults with moderate sized skull defects are best reconstructed with autogenous split rib grafts. If the defect is tremendous, split ribs will cover the brain and silicone can be used later to further bolster the contour. In the older age group with other contraindications for rib resections an acrylic contour piece is simple and effective. For extensive congenital anomalies an acrylic onlay can transform a generally bizarre shape into a more normal contour.