We describe the complex time dependence of the buildup of force exerted by a clamped photoelastomer under illumination. Nonlinear (non-Beer) absorption leads to a bleaching wave of a significant cis isomer dye concentration deeply penetrating the solid with a highly characteristic dynamics. We fit our experimental response at one temperature to obtain material parameters. Force-time data can be matched at all other temperatures with no fitting required; our model provides a universal description of this unusual dynamics. The description is unambiguous since these are clamped systems where gross polymer motion is suppressed as a possible source of anomalous dynamics. Future experiments are suggested.
The most common lacrimal sac pathology is chronic inflammation with or without occlusive fibrosis. However, a substantial number of lacrimal sac-specific pathologies were reported throughout the literature which may mimic chronic inflammation and be misdiagnosed. From a tertiary ophthalmic care centre in Serbia, in a single ophthalmic pathology laboratory, during a 7-year period (January 2004 to October 2010), a 599 consecutive lacrimal sac wall biopsy samples routinely obtained during external dacryocystorhinostomy in adult patients with clinically presumed primary acquired lacrimal drainage system obstruction were analysed. Although non-specific lacrimal sac pathology was present in the vast majority of cases (578 biopsy specimens; 96.49%), this report also reveals a relatively substantial number (21 biopsy specimens; 3.51%) of clinically non-suspected or intraoperatively unexpected primary lacrimal sac-specific pathology--among them, six lesions with malignant biological behaviour were identified: one microinvasive squamous cell carcinoma and five malignant lymhoproliferative lesions. Usefulness of routine lacrimal sac wall biopsy during surgery for primary acquired lacrimal drainage system obstruction is undoubtful and commensurate with the constant need for better understanding of the pathological processes that involve lacrimal drainage system.
Purpose
Patients with Graves’ orbitopathy can present with asymmetric disease. The aim of this study was to identify clinical characteristics that distinguish asymmetric from unilateral and symmetric Graves’ orbitopathy.
Methods
This was a multi-centre study of new referrals to 13 European Group on Graves’ Orbitopathy (EUGOGO) tertiary centres. New patients presenting over a 4 month period with a diagnosis of Graves’ orbitopathy were included. Patient demographics were collected and a clinical examination was performed based on a previously published protocol. Patients were categorized as having asymmetric, symmetric, and unilateral Graves’ orbitopathy. The distribution of clinical characteristics among the three groups was documented.
Results
The asymmetric group (
n
= 83), was older than the symmetric (
n
= 157) group [mean age 50.9 years (SD 13.9) vs 45.8 (SD 13.5),
p
= 0.019], had a lower female to male ratio than the symmetric and unilateral (
n
= 29) groups (1.6 vs 5.0 vs 8.7,
p
< 0.001), had more active disease than the symmetric and unilateral groups [mean linical Activity Score 3.0 (SD 1.6) vs 1.7 (SD 1.7),
p
< 0.001 vs 1.3 (SD 1.4),
p
< 0.001] and significantly more severe disease than the symmetric and unilateral groups, as measured by the Total Eye Score [mean 8.8 (SD 6.6) vs 5.3 (SD 4.4),
p
< 0.001, vs 2.7 (SD 2.1),
p
< 0.001].
Conclusion
Older age, lower female to male ratio, more severe, and more active disease cluster around asymmetric Graves’ orbitopathy. Asymmetry appears to be a marker of more severe and more active disease than other presentations. This simple clinical parameter present at first presentation to tertiary centres may be valuable to clinicians who manage such patients.
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