A Review on the Alzheimer Disease Animal Models and Retinal Degeneration

Alzheimer’s disease (AD) is a chronic neurodegen- erative disease, serving as the most common form of dementia among the elderly population. AD targets various neurological processes in humans such as the visual pathway and hence resulting in various forms of visual abnormalities. Several studies have reported the loss of retinal ganglion cells, reduced thickness of nerve fibre layers (NFL) and damage of the optic nerve head and fiber layers. These findings suggest a putative link between AD and visual function deficits. As genetic defects have been found to be associated with AD, it is possible to experimentally mimic this condition in animal models. AD gene mutations discovered in human amyloid pre- cursor protein (APP), presenilin 1/2 (PS1/PS2) and microtubule- associated tau protein have been used to engineer AD animal models. In this review, we discuss the underlying molecular mecha- nisms of AD in terms of amyloidogenesis and tauopathies, as well as explain the pathological changes leading to vision loss in AD patients. Subsequently, the biology of the genes/proteins which have a causative link to AD, including APP, PS1 and PS2 will be discussed. Several recent reports of retinal degeneration in AD transgenic mouse models are selected to examine the relationship between AD and visual disturbance. We believe that a well- established method to generate transgenic mice will enhance our understanding of AD pathology and its correlation with retinal degeneration, leading to possible detection and treatment methods for AD

Research on the Cleaning Efficacy of Micro-bubbles on Dental Plaque

AbstractLong-term bed-ridden patients do not usually have the same opportunity for proper dental hygiene as normal individuals, as they often have difficulty using toothbrushes to clean their teeth. Patients with periodontal disease are also at risk of increased bacterial infection due to the propensity for teeth brushing causing bleeding of the gums. Therefore, an alternative method of dental hygiene maintenance is required for these individuals. Our study proposed a method to clean dental plaque through a tooth tray with micro-bubbles and verified its cleaning efficacy through experiment. A cleaning device that produces micro bubbles (Braun MD20) was used in the study with five separately modified nozzle diameters as the independent variable: 0.16mm, 0.30mm, 0.63mm, 0.8mmand 1.2mm. The five different rotation speed settings of the device act as the other independent variable, with the resulting flow volume, velocity and the diameter of the micro-bubbles as the intermediate variables. The effects of these variables on cleaning dental plaque were investigated. Our results showed that an average of 45%∼75% cleaning rate of dental plaque was achieved under all combinations of the variables. The best dental plaque removal variable combination was nozzle diameter 0.8mm with speed of 3527rpm, in which 98% dental plaque removal was achieved. The dimension of the nozzle exerted greater influence on flow volume, flow velocity and bubble diameter than rotation speed. The effect of the control variables on plaque removal was also more significant than intermediate variables, with the nozzle dimension influencing plaque removal at 0.05 significance level

Drug discovery from Chinese medicine against neurodegeneration in Alzheimer's and vascular dementia

Alzheimer's disease and vascular dementia are two major diseases associated with dementia, which is common among the elderly. While the etiology of dementia is multi-factorial and complex, neurodegeneration may be the major cause of these two diseases. Effective drugs for treating dementia are still to be discovered. Current western pharmacological approaches against neurodegeneration in dementia develop symptom-relieving and disease-modifying drugs. Current integrative and holistic approaches of Chinese medicine to discovering drugs for neurodegeneration in dementia include (1) single molecules from the herbs, (2) standardized extracts from a single herb, and (3) herbal formula with definite composition. This article not only reviews the concept of dementia in western medicine and Chinese medicine but also evaluates the advantages and disadvantages of these approaches

The Space-Time Conservation Element and Solution Element Method-A New High-Resolution and Genuinely Multidimensional Paradigm for Solving Conservation Laws

Without resorting to special treatment for each individual test case, the 1D and 2D CE/SE shock-capturing schemes described previously (in Part I) are used to simulate flows involving phenomena such as shock waves, contact discontinuities, expansion waves and their interactions. Five 1D and six 2D problems are considered to examine the capability and robustness of these schemes. Despite their simple logical structures and low computational cost (for the 2D CE/SE shock-capturing scheme, the CPU time is about 2 micro-secs per mesh point per marching step on a Cray C90 machine), the numerical results, when compared with experimental data, exact solutions or numerical solutions by other methods, indicate that these schemes can accurately resolve shock and contact discontinuities consistently