Ultra-broadband frequency shifting of laser pulses in a square multicore chalcogenide fiber.

The process of Raman frequency shifting of out-of-phase laser pulses in fibers with a square configuration of weakly coupled cores having two or more zero dispersion wavelengths has been studied. The use of out-of-phase distributions in multicore fibers makes it possible to increase pulse energies by orders of magnitude in comparison with the case of single-core fibers. Conditions for the stability of out-of-phase laser pulses are determined and confirmed by numerical simulations. A configuration of chalcogenide multicore fiber with three zero dispersion wavelengths is proposed, allowing ultra-broadband frequency shifting of laser pulses up to 6.2 µm with an energy efficiency of more than 25%.

Stable few-cycle out-of-phase solitons in a rectangular multi-core fiber.

Stable out-of-phase soliton-like distributions of the wave field with few-cycle durations are found in fibers consisting of a rectangular lattice of weakly coupled cores. The stability of found distributions for durations larger than the critical value is shown analytically and numerically. Numerical simulation shows that the radiation of linear dispersive waves rather quickly transforms shorter pulses to the found solution with critical duration.

Laser pulse cutoff at nonlinear reflection due to Raman backscattering in plasma.

A method for generating subrelativistic laser pulses with a sharp leading edge is proposed, which is based on Raman backscattering of an intense short pump pulse by a counter-propagating long low-frequency pulse propagating in a thin plasma layer. A thin plasma layer serves both to attenuate parasitic effects and to effectively reflect the central part of the pump pulse when the field amplitude exceeds the threshold value. A prepulse with a lower field amplitude passes through the plasma almost without scattering. This method works for subrelativistic laser pulses with durations up to 100 fs. The contrast of the leading edge of the laser pulse is determined by the seed pulse amplitude.

Coherent amplification of high-power laser radiation in multicore fibers from a rectangular array of cores.

The coherent propagation and amplification of high-power laser radiation in a multicore fiber consisting of a square array of weakly bound cores are studied. Exact stable analytical solutions are found for the out-of-phase mode, which describes the coherent propagation of wave beams in such fibers. The analytical results are confirmed by direct numerical simulation of the wave equation. The stability conditions of the out-of-phase mode in the active medium are found.

Improved tolerability of neratinib in patients with HER2-positive early-stage breast cancer: the CONTROL trial.

BACKGROUND: Neratinib is an irreversible pan-HER tyrosine kinase inhibitor approved for extended adjuvant treatment in early-stage HER2-positive breast cancer based on the phase III ExteNET study. In that trial, in which no antidiarrheal prophylaxis was mandated, grade 3 diarrhea was observed in 40% of patients and 17% discontinued due to diarrhea. The international, open-label, sequential-cohort, phase II CONTROL study is investigating several strategies to improve tolerability. PATIENTS AND METHODS: Patients who completed trastuzumab-based adjuvant therapy received neratinib 240 mg/day for 1 year plus loperamide prophylaxis (days 1-28 or 1-56). Sequential cohorts evaluated additional budesonide or colestipol prophylaxis (days 1-28) and neratinib dose escalation (DE; ongoing). The primary end point was the incidence of grade ≥3 diarrhea. RESULTS: Final data for loperamide (L; n = 137), budesonide + loperamide (BL; n = 64), colestipol + loperamide (CL; n = 136), and colestipol + as-needed loperamide (CL-PRN; n = 104) cohorts, and interim data for DE (n = 60; completed ≥six cycles or discontinued; median duration 11 months) are available. No grade 4 diarrhea was observed. Grade 3 diarrhea rates were lower than ExteNET in all cohorts and lowest in DE (L 31%, BL 28%, CL 21%, CL-PRN 32%, DE 15%). Median number of grade 3 diarrhea episodes was one; median duration per grade 3 episode was 1.0-2.0 days across cohorts. Most grade 3 diarrhea and diarrhea-related discontinuations occurred in month 1. Diarrhea-related discontinuations were lowest in DE (L 20%, BL 8%, CL 4%, CL-PRN 8%, DE 3%). Decreases in health-related quality of life did not cross the clinically important threshold. CONCLUSIONS: Neratinib tolerability was improved with preemptive prophylaxis or DE, which reduced the rate, severity, and duration of neratinib-associated grade ≥3 diarrhea compared with ExteNET. Lower diarrhea-related treatment discontinuations in multiple cohorts indicate that proactive management can allow patients to stay on neratinib for the recommended time period. CLINICALTRIALS.GOV: NCT02400476.

Coherent propagation and amplification of intense laser pulses in hexagonal multicore fibers.

Propagation and amplification of intense coherent laser pulses in a multicore fiber of 24 weakly coupled cores arranged in the form of seven close-packed hexagons were studied. Exact stable analytical solutions are found for the out-of-phase mode, which describes the coherent propagation of wave beams and temporal soliton solutions in such fibers. Their stability is demonstrated. The analytical results are confirmed by the direct numerical simulation of the wave equation.

Laser pulse compression up to few-cycle durations in multicore fiber.

A mechanism for self-compression of laser pulses in a multicore fiber on the basis of nonlinear combining of radiation from many cores, surrounding the central core in a ring and its trapping into the central core in a chirp-free and pedestal-free soliton-like pulse, is proposed. It is shown that the compression ratio is weakly dependent on the energy and the number of cores in the fiber and approximately equal to 6 with an almost 100% energy efficiency. The compression ratio can be increased to 40 with an efficiency of more than 50% by using additional compression of longer pulses with approximately the same energy. The possibility of a 38-fold compression of a laser pulse to a duration of 15 fs with a pulse energy of 4 nJ in the fiber with realistic parameters was demonstrated numerically.

High-energy femtosecond pulse shaping, compression, and contrast enhancement using multicore fiber.

Nonlinear spatiotemporal dynamics of femtosecond pulses in a hexagonal seven-core silica fiber pumped by a sub-µJ 370 fs Er:fiber chirped pulse amplification (CPA) system were studied. Nonlinear pulse shaping and compression in the central core and pedestal coupling to the outer cores were directly measured by frequency-resolved optical gating. Further compression of the pulses spectrally broadened in the multicore fiber down to 53 fs was demonstrated. Two orders of magnitude contrast enhancement of the pulses after compression was observed.

Partial penectomy. Technique to eliminate meatal stricture.

A surgical technique for partial penile amputation is described which prevents meatal retraction and stenosis, and results in a functionally and cosmetically acceptable phallus.

Leiomyosarcoma of renal vein.

Primary leiomyosarcoma of the renal vein has not been previously reported in the urologic literature. A case report with long-term survival is described and the literature reviewed.

Comparison of serum and prostatic levels of tobramycin.

Tobramycin sulfate, an aminoglycoside antibiotic, has been shown to be effective in the treatment of complicated urinary tract infections. Because of this, a study was undertaken to determine the penetrance of tobramycin into the prostate gland. It was found that the drug is concentrated at inhibitory levels in the prostate gland after the routinely recommended administration and should be useful in the treatment of bacterial prostatic infection.

Evaluation of closed suprapubic cystostomy.

Closed suprapubic cystostomy is an expeditious procedure for a variety of clinical conditions requiring urinary drainage. Its benignity is reflected by a low complication rate of 1.6 per cent and no deaths in this series of 244 consecutive patients. Nevertheless, major complications can occur if proper technique is not adhered to or contraindications are not observed.

Cefazolin and cephalexin levels in prostatic tissue and sera.

A study was carried out on 18 patients given cefazolin intramuscularly and 17 patients given cephalexin by mouth preoperatively prior to transurethral resection of the prostate. Prostatic tissue and serum levels of the two drugs were determined and contrasted with previously reported mean inhibitory concentrations. It was found that cefazolin was present in the sera and prostatic tissues in levels greater than was cephalexin and that cefazolin frequently exceeded the minimum inhibitory concentrations necessary for sensitive organisms to be affected, whereas cephalexin did not. Therefore, it would appear that cefazolin would be preferable to cephalexin in treatment of acute bacterial prostatitis.

Effectiveness of smokeless ashtrays.

Most environmental tobacco smoke (ETS) issues from the tips of smoldering cigarettes between puffs. Smokeless ashtrays are designed to reduce ETS exposure by removing particulate and/or gas-phase contaminants from this plume. This paper describes an experimental investigation of the effectiveness of four smokeless ashtrays: two commercial devices and two prototypes constructed by the authors. In the basic experimental protocol, one or more cigarettes was permitted to smolder in a room. Particulate or gas-phase pollutant concentrations were measured in the room air over time. Device effectiveness was determined by comparing pollutant concentrations with the device in use to those obtained with no control device. A lung deposition model was applied to further interpret device effectiveness for particle removal. The commercial ashtrays were found to be substantially ineffective in removing ETS particles because of the use of low-quality filter media and/or the failure to draw the smoke through the filter. A prototype ashtray using HEPA filter material achieved better than 90% particle removal efficiency. Gas-phase pollutant removal was tested for only one prototype smokeless ashtray, which employed filters containing activated carbon and activated alumina. Removal efficiencies for the 18 gas-phase compounds measured (above the detection limit) were in the range of 70 to 95%.