Dynamic modelling of electrooptically modulated vertical compound cavity surface emitting semiconductor lasers

A generalized rate equation model is used to simulate the interrelated amplitude and frequency modulation properties of Electrooptically Modulated Vertical Compound Cavity Surface Emitting Semiconductor Lasers in both large and small signal modulation regimes. It is shown that the photon lifetime in the modulator subcavity provides the ultimate limit for the 3 dB modulation cutoff frequency. It is shown that there is an optimum design (number of periods) of both the intermediate and top multistack reflectors to maximise the large-signal modulation quality

Corticosteroid Use and Recurrence Risk Factors in Granulomatous Mastitis: A 17-Year Saudi Arabian Cohort Study—Steroids in Granulomatous Mastitis

Background: Granulomatous mastitis (GM) is a rare, chronic inflammatory breast condition with poorly understood etiology and variable clinical presentation. The efficacy of corticosteroid therapy in reducing recurrence remains controversial, particularly in Middle Eastern populations where the condition appears more prevalent. This study aimed to describe the demographic and clinical characteristics of patients with GM, evaluate the efficacy of corticosteroid therapy in reducing recurrence rates, and identify risk factors associated with disease recurrence. Methods: A retrospective cohort analysis was conducted on 56 patients diagnosed with GM between 2003 and 2020 at a single tertiary referral center. Patients were stratified into two groups based on steroid use (n = 14 with steroids and n = 42 without steroids). Results: The mean age of the cohort was 46.3 ± 13.2 years, with no significant differences in baseline characteristics between the steroid and non-steroid groups. The most common presentation was a breast mass (32.69%), often associated with abscess formation (25%). Core biopsy was the primary diagnostic tool used (51.79%). Recurrence of GM occurred in 10 patients (18%) overall: 7 patients (17%) in the non-steroid group and 3 patients (21%) in the steroid group. The difference in recurrence rates between the treatment groups was not statistically significant (HR = 1.40, 95% CI:0.30–6.52, p = 0.671). A history of infection (HR = 5.85, 95% CI: 1.60–21.44, p = 0.008) and hormonal disorders (hyperprolactinemia in one patient) (HR = 13.90, 95% CI: 1.43–135.52, p = 0.024) were significantly associated with recurrence. Conclusions: GM remains diagnostically challenging with an 18% recurrence rate in our cohort. We observed no statistically significant reduction in recurrence with corticosteroids, though our analysis was limited by sample size. These findings suggest that targeted management of these conditions may be beneficial in GM patients, though larger multicenter studies are needed to confirm these associations and establish standardized treatment protocols