This threshold intraocular pressure depends on the phase shift, varying over a range of approximately 1.5mmHg for mean ICP of 0mmHg. There are two encouraging features emerging from this model: first, the threshold for the onset of large amplitude oscillations appears to be an approximately linear relationship between the IOP and the CSF pressure over a significant range, consistent with measurements in canines; second, predictions show only a modest dependency on the phase shift between the IOP and the ICP oscillations – for the model parameters chosen the maximal difference in the predicted onset IOP was 1.5mmHg across the range of phase shift. The model employs an idealized representation of the elastic vessel wall (neglecting bending stiffness), assumes simple sinusoidal waveforms for the ICP and IOP and neglects pulsatility in the inlet flow into the vein. The model also assumes that the diameter of the vein is constant along its length and ignores bifurcations. When the mean IOP is 18.5mmhg then the ICP is 0mmhg, IOP is increased to 18.5mmHg, the vessel wall in compartment
In addition, the anisotropic responses of porcine sclera in the presence of shear stress were quantified through a new strain measurement technique, namely, ultrasound speckle tracking . Downs et al.  in this case characterized the linear viscoelastic material properties of peripapillary sclera in both the rabbit and monkey eyes using a coupled spectral reduced relaxation function. The
The corneal thinning that occurs in Pellucid Marginal Degeneration is identified by 1- 2 mm of inferior peripheral thinning, spreading from the 4 o' clock to 8 o' clock positions . This thinning represents the clinical feature of Pellucid Marginal Degeneration in view of it resembling a crescent shaped band . The area of approximately 1-2 mm between the thinning cornea and the limbus remains unaffected and the centre of the cornea maintains its normal thickness [1,5]. The standard corneal sensation remains intact . In some cases following corneal thinning, acute hydrops or corneal perforation may result.
Orthokeratology lenses work particularly on the anterior corneal tissue, however it is not clear whether the effect is mainly on the epithelium, anterior stroma, or both (6). Moreover , there are several theories on forces which are involved in inducing corneal change in orthokeratology. One of such theory proposed that the downward pressure of the central portion of the orthokeratology lens was flattening the underlying corneal epithelial cells (6). Another theory suggested that the orthokeratology lens created an outward pulling pressure in the tear film. This pressure gradient was thought to pull the epithelial cells peripherally, hence resulting in re-distribution of epithelial cells in the cornea (6).
This theory has proposed there is a gating mechanism within spinal cord working in the pain perception which the gate will be facilitated and thus allowing the sensory input to reach our brain (Melzack & Wall, 1965). The impulse will then be interpreted by our brain and sends message which might causes either the gate to be opened wider causing higher intensity of pain or diminished the pain by closing it (Ciccarelli & White, 2012). There is psychological factor affecting in how the pain is prioritized by the brain (Sams, 2006). Melzack and Wall (1965) have proposed that sensation of pain is unlikely to be dissociated from our emotional experience which was extremely varied from the conventional theory of pain that focusing on the seriousness of injured tissues in that era. As we can see from Marina, despite the fact of the pain widespread all over her body previously was eventually subsided, her fear of being unable backs to running did actually intensified the perception of pain.
The goal directed (top-down) system is influenced by individuals’ current goals, expectations and knowledge and keeps attention to the task, while the stimulus-driven (bottom-up) attentional system is influenced by salient stimuli (Corbetta & Shulman, 2002). Many studies indicate that in individuals with high levels of anxiety the balance between these two systems can be affected and consequently altered (Corbetta & Shulman, 2002; Bishop et al, 2004). So, there is an increase in the function of the ‘’bottom-up stimulus-driven system’’, while there is a decrease in the use of the ‘’top-down goal-driven system’’, or stated in other words, attention is distracted by threatening stimuli and individuals with high levels of anxiety have not enough resources for the task at hand. Taking everything into consideration, it can be stated that anxiety does influence and impair the overall function and capacity of attentional system (Corbetta & Shulman,
Cornea was hazy with visible iris details. There was corneal epithelial loss, which extended a vertical line from 4 to 11 o clock to the limbus (Figure 1 c). Anterior chamber was deep and quite, lens was clear, there was hazy fundus view showing flat retina. The left eye had normal anterior & posterior chambers on examination. The patient was diagnosed as grade II alkali chemical eye injury.
Testing the Strength of the Electromagnet by Changing the Number of Coils Aim The aim of this experiment is to investigate how the strength of an electromagnet is affected by the number of coil turns around the iron c-core. Hypothesis As the number of wire coils increases, the strength of the magnetic field (the electromagnet’s strength) will also increase. This means that the number of paper clips that attach to the electromagnet will increase. Explanation of Hypothesis/background: When a DC (Direct Current) electric current flows through a wire, a magnetic field is created. Wrapping the wire in a coil concentrates and increases the magnetic field, because the additive effect of each turn of the wire.
Setting centrals perpendicular to alveolar ridge to establish a setting for class I patient which is the most aesthetic Get a nice soft look for the set up by setting centrals following the curve of the arch Mesial flare is esthetically unacceptable for centrals Don’t reflect in or deflect out the neck it will make one central look light and the other will look dark Avoid diastemas they don’t work for everybody Lateral mesial inclination is considered not acceptable whereas distal inclination of the long axis of the lateral is considered soft Mesial flare of lateral gives a soft effect is more feminine unlike the distal flare which is bold In young patients 1-2 mm higher than occlusal rim Canines Never upright or labial inclination The neck out palatal inclination to form the curvature of the arch Mesial flare naturally forms the arch form and never distal flare or else it will appear bold For gd overjet For gd overbite Location and orientation of the median
(1) Where ε_ij and τ_kl denote the strain and stress tensor, respectively. S_ijkl is the compliance, and it is fourth-rank tensor quantity. The direct consequence of the symmetry in the strain and the stress tensors is that only 36 components of the compliance tensor are independent and distinct terms, instead of 81 components of the compliance tensor. The relation between the stress and the strain can be simplified through applying the Voigt notation as the following: ε_i=S_ij τ_j ………….. (2) Because of the symmetry in the compliance tensor for the general anisotropic linear elastic solid, there are 21 independent elastic constants. By considering the symmetry conditions found in the wurtzite crystal structure of the ZnO NRs, the stress-strain relations are expressed as (the z-axis is the c-axis for wurtzite crystal): …………….