Wide-range optical carrier recovery via broadened Brillouin filters.

Stimulated Brillouin scattering has great potential for wide-wavelength-range optical carrier recovery, as it can act as a parametrically defined narrowband gain filter. However, due to the dispersion of the Brillouin frequency shift, prior demonstrations have been limited in wavelength range. Here, we demonstrate that frequency modulating the pump light for a gain filter based on stimulated Brillouin scattering enables optical carrier recovery for a broad range of input wavelengths.

Pure PBL, Hybrid PBL and Lecturing: which one is more effective in developing cognitive skills of undergraduate students in pediatric nursing course?

Background: Nursing education in Iran has conventionally focused on lecture-based strategies. Improvements in teaching and learning over the years have led to an expansion of the pedagogies available to educators. Likewise, there has been a suggestion for a move toward more learner-centered teaching strategies and pedagogies that can result in improvement in learning.

Brillouin spectroscopy of a hybrid silicon-chalcogenide waveguide with geometrical variations.

Recent advances in design and fabrication of photonic-phononic waveguides have enabled stimulated Brillouin scattering in silicon-based platforms such as underetched silicon waveguides and hybrid waveguides. Due to the sophisticated design and, more importantly, high sensitivity of the Brillouin resonances to geometrical variations in micro- and nano-scale structures, it is necessary to have access to the localized opto-acoustic response along those waveguides to monitor their uniformity and maximize their interaction strength. In this Letter, we design and fabricate photonic-phononic waveguides with a deliberate width variation on a hybrid silicon-chalcogenide photonic chip and confirm the effect of the geometrical variation on the localized Brillouin response using a distributed Brillouin measurement.

Gain-shift induced by dopant concentration ratio in a Thulium-Bismuth doped fiber amplifier.

This paper details the effect of Thulium and Bismuth concentration ratio on gain-shift at 1800 nm and 1400 nm band in a Thulium-Bismuth Doped Fiber Amplifier (TBDFA). The effect of Thulium and Bismuth's concentration ratio on gain shifting is experimentally established and subsequently numerically modeled. The analysis is carried out via the cross relaxation and energy transfer processes between the two dopants.

Micro-bending based optical band-pass filter and its application in S-band Thulium-doped fiber amplifier.

A new approach for filtering an optical band-pass in optical amplifier is proposed using a macro bending. The proposed filter leverages the bending loss of higher order modes at shorter wavelengths. At longer wavelengths, the filter increases fiber's bending loss as the fundamental mode 'tail' is leak out from the cladding.

The recent-transmission of Mycobacterium tuberculosis strains among Iranian and Afghan relapse cases: a DNA-fingerprinting using RFLP and spoligotyping.

Background: Relapse of tuberculosis (TB) may develop as the result of reactivation of the endogenous primary infection, or as a result of a exogenous reinfection. This survey evaluated the rate of reactivation versus recent transmission among Iranian and Afghan relapse cases.

Methods: The sputum specimens were digested, examined microscopically for acid-fast bacilli, and inoculated into Löwenstein-Jensen slants by standard procedures.

Linear optical and quadratic electro-optic response of carbon nanotubes: universal analytic expressions for arbitrary chirality.

Using a universal density of states (Mintmire and White 1998 Phys. Rev. Lett.

Extensively drug-resistant tuberculosis: 2 years of surveillance in Iran.

Background: Extensively drug-resistant (XDR) tuberculosis (TB) is a cause of concern, because it renders patients untreatable with available drugs. In this study, we documented the existence and transmission of XDR TB among patients with multidrug-resistant TB. These patients were referred to the National Research Institute of Tuberculosis and Lung Diseases (Tehran, Iran) for treatment and diagnosis from 2003 to 2005.

Evaluation of tuberculosis transmission in Tehran: using RFLP and spoligotyping methods.

Objectives: To evaluate the DNA polymorphism among Mycobacterium tuberculosis (MTB) strains isolated from new smear positive tuberculosis (TB) patients residing in Tehran capital city of Iran, during the year 2001.

Methods: IS6110-restriction fragment length polymorphism (RFLP) and spoligotyping analyses were performed on 129 M. tuberculosis strains.

Effectiveness of conservative treatment for craniomandibular disorders: a 2-year longitudinal study.

The severity of symptoms of craniomandibular disorders was studied during a 2-year period in 195 patients treated with conservative therapeutic schemes. Results revealed a continuing improvement and a statistically significant tendency for the great majority of patients to become asymptomatic or show a decrease in the severity of symptoms. By the end of the 2 years, 66.

Effect of age and sex on craniomandibular disorders.

The purpose of this study was to investigate the effect of age and sex on craniomandibular disorders. A total of 195 subjects were examined, 148 women and 47 men. The range of age was 16 to 70 years.