Colour stability of the material is an essential factor that contributes to the selection of a flexible denture material. Staining effects on the denture may result in unattractive appearance, the dissatisfaction of the wearer, and limited usage period of the denture. This study aims to identify the colour stability of the Valplast flexible denture material using three types of beverages. Methods: A total of 32 disc-shaped flexible resin materials (20 +/- 0.1 mm in diameter and thickness 3 +/- 0.1 mm) were prepared based on the manufacturer instructions. The samples were randomly divided into 4 groups of immersion: distilled water (control), coffee solution, tea solution and red wine. The samples were left in the specified immersion solution for up to 60 days. Colour changes were measured after 1, 3, 7, 14, 21, 30, 45 and 60 days of immersion. Results: The samples immersed in coffee solution changed from S1 to S2, whereas samples in tea solution changed from S1 to S3. Additionally, samples in red wine changed from S1 to S4, as observed using the Valplast colour tone guide. The highest reflection measured using spectroscopy was 65.146 at 385.19 nm of the control samples, whereas the lowest reflection was 1.974 at the wavelength of 385.97 nm on the samples immersed in the red wine. Conclusion: The most significant difference can be observed in the red wine group, followed by samples in tea and coffee solutions. Moreover, increasing the immersion period causes increasing staining effect of the denture.
Craniofacial and Biomaterial Sciences Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200, Bertam, Penang, Malaysia 2 Institut Latihan Kementerian Kesihatan Malaysia (Pergigian), No.3 Jalan Sepoy Lines, 10450 Georgetown, Penang, Malaysia 3 Division of Research and Networking, Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200, Bertam, Penang, Malaysia 4 School of Physics, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia

Traumatic injury to the eye can occur due to various causes, most of which are avoidable. Here we report three cases of intrastromal corneal foreign bodies (FB) which required surgical removal. Most corneal FBs are removed easily at the slit lamp, however, these cases required surgical intervention due to the mechanism of which the FB penetrated into the stroma. Although the mechanism of injury was similar, with all three cases occurring at high velocity, we observed that the entry and level of penetration differed in each case. In the first case, the corneal FB penetrated the cornea and was embedded in the anterior stroma, whereas in the second case, the FB was embedded in the posterior stroma, but with an intact endothelium. In the third case, the FB caused a full thickness, self-sealed laceration wound but remained embedded in the stroma. Through further evaluation, we noted that several factors contribute towards the severity of the injury, namely, anatomy of the cornea, area affected, shape, size, mass and velocity of the object. We speak in depth about the mechanism of injury and physics associated with these injuries and why the penetration differed in each case.
corneal stroma ; foreign bodies ; injury ; mechanics ; physics

In this paper, it was studied how physics affected development of optometry in the United States, from aspects of formation and academization of optometry. It was also revealed that history of optometry was analogous to history of engineering. Optics in the 19th century was divided into electromagnetic study of light and visual optics. Development of the visual optics promoted professionalization of ophthalmology that had already started in the 18th century. The visual optics also stimulated formation of optometry and optometrists body in the late 19th century of the United States. The American optometrists body were originated from opticians who had studied visual optics. Publication of several English academic textbooks on visual optics induced appearance of educated opticians (and jewelers). They acquired a right to do the eye examination in the early 20th century after C. F. Prentice's trial in 1897, evolving into optometrists. The opticians could be considered as craftsmen, and they were divided into (dispensing) opticians and optometrists. Such history of American optometrists body is analogous to that of engineers body in the viewpoints of craftsmen origin and separation from craftsmen. Engineers were also originated from educated craftsmen, but were separated from craftsmen when engineering was built up. Education system and academization of optometry was strongly influenced by physics, too. When college education of optometry started at American universities, it was not belonged to medical school but to physics department. Physics and optics were of great importance in curriculum, and early faculty members were mostly physicists. Optometry was academized in the 1920s by the college education, standardization of curriculum, and formation of the American Academy of Optometry. This is also analogous to history of engineering, which was academized by natural sciences, especially by mathematics and physics. The reason why optometry was academized not by medicine but by physics is because ophthalmologists did not have conciliatory attitudes to optometry education. Optometry became independent of physics from the 1930s to the 1940s. Optometric researches concentrated on binocular vision that is not included to discipline of physics, and faculty members who majored in optometry increased, so that optometry departments and graduate schools were established around 1940. Such independence from natural sciences after academization also resembles history of engineering. On the contrary, history of optometry was different from history of ophthalmology in several aspects. Ophthalmology had already been formed in the 18th century before development of visual optics, and was not academized by visual optics. Ophthalmologists body were not originated from craftsmen, and were not separated from craftsmen. History of optometry in the United States from the late 19th to the mid 20th century is analogous to history of engineering rather than history of medicine, though optometry is a medical discipline.
History, 19th Century ; History, 20th Century ; Humans ; Ophthalmology/history ; Optics and Photonics/history ; Optometry/*history ; Physics/*history ; United States

The link between micro- and macro-parameters for radiation interactions that take place in living biological systems is described in this paper. Meanwhile recent progress and development in microdosimetry and nanodosimetry are introduced, including the methods to measure and calculate these micro- or nano-parameters. The relationship between radiobiology and physical quantities in microdosimetry and nanodosimetry was presented. Both the current problems on their applications in radiation protection and radiotherapy and the future development direction are proposed.
Humans ; Physics ; Radiation Protection ; Radiobiology ; Radiometry

This paper introduces the development on the research of measuring theory for orthopaedic biomechanics in detail. Then, the measuring method and corresponding measuring device are also mentioned. Advantages, disadvantages and development for the device are also introduced. Finally, the research prospect for it is introduced.
Biomechanical Phenomena ; Bone and Bones ; physiology ; physiopathology ; Physics ; instrumentation ; methods

Taiki is a kind of fundamental vital energy filling the upper aspect of the body, and it can fall because of stress, heavy labor, diarrhea, excessive intake of drugs for regulating the flow of vital energy, or extreme deficiency in vital energy.We report the case of a 39 year old female patient who complained of dyspnea, psychic enervation, and other symptoms of falling taiki from the upper aspect of the body, caused by taking a cathartic drug (mashiningan) for constipation, while being treated for agitation and emotional incontinence. Shokanto improved this state of falling taiki from the upper aspect of the body.
Energy, Physics ; Vital ; Cathartics ; g <3> ; Due to

The same physics applies to the largest scale, Universe, as well as to the smallest scale, Elementary Particles
Elementary Particles ; Physics

Oriental medicine explains that Kikyo (deficiency of Qi) is an exhausted state of the human body's energy. Hence a lack of energy state could be equal to a state of low metabolism. It would affect any blood test. Kikyo-scores were evaluated in 333 new patients who had visited our clinic within a 13-month period, and their blood samples were collected on the same days. A chi-square test was done with the Kikyo cases, indicating points of 30 and above of Kikyo-score, and patients who indicated lower than standard levels in their blood tests. A relationship between Kikyo, and points lower than normal chemical screening test values was proved (p<0.0001). Forty-nine percent of Kikyo-patients were under normal limits, but the positive predictive ratio was85%. We have to recognize it is an exhaustive Qi state we see, when chemical screening data values are low.
Qi ; deficiency ; Energy, Physics ; seconds ; Related

To prevent protein-energy malnutrition in elderly inpatients with dysphagia, weexamined the current meals for them in detail. The thickeners seemed to be a ploblem. Changes of viscosity over time and temperature were reduced when a starch thickener was changed to a xanthan gum thickener. When a gelatinizer was added to soft meals to allow cutting into shape, etc., the meals looked better were less sticky, more cohesive, and easier to eat. Thus, the smooth texture required of meals for dysphagia patients was obtained. When conventional mixed meals were changed to soft meals, there was an improvement of appearance and the meals became more palatable.The change of food intake after these improvements was investigated in five inpatients who had difficulty in swallowing. Food intake was increased in four of these five patients after these improvements, suggesting that their appetite might have been increased by improvement of the appearance and palatability of their meals. We will continue making improvements of these meals in hopes that patients can eat solid food again as early as possible.
Deglutition Disorders ; Eating ; Energy, Physics ; Solid ; Malnutrition

According to the World Health Organization (WHO), the basic sciences to support the human health are chemistry, physics and informatics. Chemistry is the base of pharmacy. Physics is the base of medical instruments and equipments (MIE). The diagnosis and therapy of diseases are relying on informatics. Therefore, as the fusion results of physics and medicine, medical physics is the creative source science of MIE. Among all diagnosis tools, medical imaging devices are the fastest-developed and the most-complicated MIE since Roentgen discovered X-ray which was quickly used in medical diagnosis in 1895. Among all treatment tools, the radiotherapeutical devices are the most-widely used and the most effective MIE for tumor treatments since Mrs. Courier found the nature radiation isotope Radium at the end of 19th century and began to use it in tumor therapy. Although the research and development (R&D) of so-complicated MIE need many subjects of science and engineering, the kernel science is medical physics. With the results of more than 50 years' development in developed countries, medical physics has defined its own field, which is the medical imaging physics and the radiotherapeutical physics. But, the definition has been expanded to be wider and wider. Therefore, we should pay more attention to the establishment of Medical Physics in China. In order to develop medical physics in china, the bases of R&D and clinical practice should be also built.
China ; Diagnostic Imaging ; Equipment and Supplies ; Health Physics ; Neoplasms ; diagnosis ; therapy ; Physics ; instrumentation