Accommodation amplitude

Previous studies have shown that accommodation mediated via ciliary smooth muscle activity also receives sympathetic innervation. Sympathetic nerves reach the ciliary muscle through the uveal blood vessels in close association with arteries and terminal arterioles. The distribution of the adrenergic fibers in the ciliary muscle appears to vary across species. In primates sympathetic nerve terminals, mainly 3 receptors, can generally be found in the anterior portion of the ciliary muscle. The accommodative amplitude significantly decreased in human subjects after instillation of phenylephrine (an a agonist) or hydroxyamphetamine (an a and (3 agonist). Such observations provide evidence that both sympathetic and parasympathetic divisions of the autonomic nervous system can affect accommodation but not equally. Furthermore, the nature of sympathetic innervation can be summarized as follows ... 

Accommodative amplitude measurements after instillation of 2.5% or 10% phenylephrine generally indicate that the effect is far less than the decrease observed with cycloplegic agents such as tropicamide (see Chapter 9). A loss of approximately 2.00 D (7.93 D from 9.95 D) at... 

Dapiprazole was specifically developed for ocular use. After topical instillation it produces miosis and a reduction in lOP. Like thymoxamine, dapiprazole reverses mydriasis by blocking a receptors in the iris dilator muscle. Concentrations ranging from 0.12% to 1.5% significantly reduce pupil size in both normal and glaucomatous eyes. The miotic effect is concentration dependent and can last up to 6 hours after instillation. lOP can be reduced for up to 6 hours. In patients with decreased amplitude of accommodation associated with tro-picamide-induced cycloplegia, dapiprazole may partially increase the accommodative amplitude (Figure 8-5). This restoration of near vision seems to come from a combination of increasing depth of field due to pupillary recovery and an actual increase in accommodative amplitude independent of pupillary size. 

The outline of this paper is as follows. First, a theoretical model of unsteady motions in a combustion chamber with feedback control is constructed. The formulation is based on a generalized wave equation which accommodates all influences of acoustic wave motions and combustion responses. Control actions are achieved by injecting secondary fuel into the chamber, with its instantaneous mass flow rate determined by a robust controller. Physically, the reaction of the injected fuel with the primary combustion flow produces a modulated distribution of external forcing to the oscillatory flowfield, and it can be modeled conveniently by an assembly of point actuators. After a procedure equivalent to the Galerkin method, the governing wave equation reduces to a system of ordinary differential equations with time-delayed inputs for the amplitude of each acoustic mode, serving as the basis for the controller design. 

The device must be dimensioned so that at resonance a half-wavelength is accommodated in the distance L. The amplitude of motion at the outer metal surface will be related to that of the ceramic through the ratio q of their acoustic... 

Fig. 7 Development of fatigue cracks in an epoxy/glass contact under gross slip condition (1Hz, displacement amplitude 60 xm) (from [97]). White arrows indicate the occurrence of crack initiation and propagation at the edge of the contact under the action of tensile stresses. The lateral contact stiffness, K, is essentially a measurement of the elastic response of the epoxy substrate within the contact zone. Brittle crack propagation is associated to a drop in stiffness due to the additional accommodation of the imposed displacement provided by crack opening mechanisms...

Amplitude of Accommodation. Because of the cycloplegic and mydriatic effects of anticholinergic drugs, amplitude... 

To within 2 D of original amplitude of accommodation abUity to read fine print is possible by the third day after atropine and scopolamine instillation and by 6 hours after homatropine instillation. 

One instmment capable of measuring the dynamic shear modulus is a dynamic mechanical analyzer (DMA). A DMA measures the viscoelastic properties of a material by measuring the mechanical response that is deformed under periodic stress. Operation of a DMA tool offered by TA Instruments is as follows The sample is clamped between the ends of two parallel arms, which are mounted on low-force flexure pivots, allowing motion only in the horizontal plane. The distance between the two arms is adjustable by means of a precision mechanical slide to accommodate a wide range of sample lengths (from < 1 mm up to 65 mm). An electromagnetic motor attached to one arm drives the arm/sample to a strain (amplitude) selected by the operator. As the arm/sample system is displaced, the sample undergoes a flexural deformation [as depicted schemati-... 

The loss of intensity with increasing temperature in the quadrupolar d—d transitions of the tetrahedral halide complexes [C0X4 ] is accommodated by a calculation of the mean-square amplitudes of vibration in the electronic ground state as a function of temperature for the four tetrahedral modes ). The observed temperature dependence of the d—d transitions to the Ti (F) and Ti (P) excited state from the... 

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