Highly efficient, high average power, narrowband, pump-tunable BWOPO.

We demonstrate a continuously tunable mid-infrared source that produces narrowband radiation at 1981 nm and 2145 nm based on a tunable Yb-based hybrid MOPA pump and a backward-wave optical parametric oscillator (BWOPO). The BWOPO employs a PPRKTP crystal with 580 nm domain periodicity. The BWOPO has a record-low oscillation threshold of 19.

Beat note stabilization in dual-polarization DFB fiber lasers by an optical phase-locked loop.

A fully fibered microwave-optical source at 1.5 µm is studied experimentally. It is shown that the beat note between two orthogonally polarized modes of a distributed-feedback fiber laser can be efficiently stabilized using an optical phase-locked loop.

Efficacy and safety of a switch to rilpivirine-based regimens in treatment-experienced HIV-1-infected patients: a cohort study.

Background: Rilpivirine (RPV) is a second-generation once-daily non-nucleoside reverse transcriptase inhibitor (NNRTI) which has shown non-inferior antiviral activity to efavirenz in treatment-naive patients. Data in treatment-experienced patients are more limited. We wished to assess the efficacy and safety of a switch to RPV-based regimens in well-suppressed treatment-experienced patients.

Beta-lactamase stability of imipenem.

The beta-lactamase stability and interactions of imipenem were analysed in comparison with those of cefazolin, cefuroxime, cefoxitin, cefotaxime, ceftazidime, mezlocillin, piperacillin and penicillin G for a set of representative beta-lactamases. These enzymes included penicillinases such as those obtained from Staphylococcus aureus, Escherichia coli and other Enterobacteriaceae (TEM-1 and similar enzymes) (group A); cephalosporinases produced by Esch. coli (Amp C type), Serratia liquefaciens, Enterobacter cloacae, Pseudomonas aeruginosa (group B); and beta-lactamases produced by Klebsiella spp.

[Klebsiella oxytoca beta-lactamases: study of their action on 3d-generation cephalosporins].

Indole-positive Klebsiella pneumoniae or K. oxytoca are usually resistant to penicillins as a result of the production of a chromosomally-mediated beta-lactamase with a low level of synthesis (specific activity approximately 50 to 100 mU/mg). Although most strains are susceptible to the majority of cephalosporins, some strains exhibit resistance to cephalosporins including third-generation drugs.