Efficient graphene saturable absorbers on D-shaped optical fiber for ultrashort pulse generation.

We demonstrated a method to construct high efficiency saturable absorbers based on the evanescent light field interaction of CVD monolayer graphene deposited on side-polished D-shaped optical fiber. A set of samples was fabricated with two different core-graphene distances (0 and 1 µm), covered with graphene ranging between 10 and 25 mm length. The mode-locking was achieved and the best pulse duration was 256 fs, the shortest pulse reported in the literature with CVD monolayer graphene in EDFL. As result, we find a criterion between the polarization relative extinction ratio in the samples and the pulse duration, which relates the better mode-locking performance with the higher polarization extinction ratio of the samples. This criterion also provides a better understanding of the graphene distributed saturable absorbers and their reproducible performance as optoelectronic devices for optical applications.

Oral health in prehistoric San Pedro de Atacama oases, Northern Chile.

After almost 2000 years of local development, including limited trading with neighboring ethnic groups, the societies that occupied the oases of San Pedro de Atacama, Northern Chile, became part of the trade web of the Tiwanaku empire, between 500 and 1000 CE. Archaeological evidence tends to support the idea that the period under the influence of the altiplano (high plane) empire was very affluent. Here we investigate the possibility that this affluence had a positive impact on the health status of the Atacameneans, using the oral health as an indirect indicator of quality of life. Dental decay, dental abscess, dental wear, linear enamel hypoplasia, periodontal disease and dental calculus were analyzed on 371 skeletons from 12 sites from San Pedro de Atacama oases. We believe that if, indeed, there were better biological conditions during the altiplano influence, this could have been caused by the access to a more diversified food intake promoted by the intensification of the trading network established by Tiwanaku in the central-south Andes, of which San Pedro de Atacama became an important node.

Causes of nonuse of corneas donated in 2007 in Minas Gerais.

UNLABELLED: We sought to unfold the causes of nonuse of donated corneas in 2007 in the state of Minas Gerais, seeking to show the flaws in the process that could be repaired in to achieve a better rate of collection and transplantation. METHODS: We analyzed, the medical records of multiple organ donors (with brain death) and tissue donors (with heart stopped) in the data system of Tissue Banks and the Human Eye of Minas Gerais to identify the reasons for discard of donated and collected corneas for transplantation. RESULTS: The survey showed that 14% of donated corneas were not removed, 62% were used for transplantation (optical and tectonics), and 24% were removed but not transplanted. There were several reasons for transplantation failure after the withdrawal, including contraindications (sepsis, positive serology [anti-HIV, anti-hepatitis B and C], beyond 6 hours after death, and unsatisfactory quality of the donated tissue upon biomicroscopic evaluation and/or endothelial counting). CONCLUSIONS: Recognition of the causes of rejecting donated corneas allows the possibility of actions to reduce preventable causes of discard, thereby reducing the number of donated and not transplanted corneas. Causes, such as extended time between death and removal of corneas or between death and preservation of corneas, can be reduced to effectively increase the number of cornea transplantations.

Antimicrobial susceptibility and survey of macrolide resistance mechanisms among Streptococcus pyogenes isolated in Rio de Janeiro, Brazil.

A total of 357 clinical Streptococcus pyogenes isolates collected between 1994 and 1999 in Rio de Janeiro city were tested for susceptibility to 10 antimicrobial drugs by agar-diffusion tests. All isolates were susceptible to penicillin, cephems, and vancomycin. High resistance rates were observed for tetracycline (43.1%) and trimethoprim/sulfamethoxazole (77.9%). Three isolates (0.8%) were resistant to erythromycin, and three exhibited intermediate susceptibility. Determination of the erythromycin MICs by the agar dilution method, showed 1.6% of erythromycin resistant isolates (the three erythromycin-resistant and the three erythromycin-intermediate isolates found by agar-diffusion test). Of the erythromycin-resistant isolates subjected to the double-disc diffusion test for erythromycin and clindamycin, three isolates expressed the iMLSB and three the M phenotype. The resistance phenotypes were confirmed by comparing the clindamycin MICs determined under normal testing conditions and those determined after induction by pre-growth in 0.06 microg/ml of erythromycin. Three ermTR and three mefA-containing isolates were detected by PCR. In strains belonging to the iMLSB phenotype, two clones were identified by PFGE following restriction with SmaI. M phenotype isolates could not be restricted with SmaI. Our results indicate a low rate of erythromycin resistance among S. pyogenes isolated in Rio de Janeiro, Brazil, and pointed to the presence of both resistance mechanisms found in streptococci.