Effects of weak input side mode suppression ratio and output filtration on the intensity noise of a self-seeded gain switched optical pulses at 2.5 GHz

Mode partition noise is shown to be a cause for concern in terms of the intensity noise induced on a self-seeded gain-switched pulse when filtering is used to increase the side mode suppression ratio (SMSR) of the output signal to >30 dB. The inherent SMSR of a self-seeded gain switched pulse is revealed to be a vital parameter especially when output filtration is used. Our results portray the fact that such a procedure would lead to an introduction of noise on the SSGS pulses if the inherent SMSR is weak, and may ultimately determine whether or not a source is suitable for use in WDM or OTDM optical communication networks

80 Gb/s optimised pulse source using a gain-switched laser diode in conjunction with a nonlinearly chirped grating

The authors demonstrate the generation of transforms limited short optical pulses, which display excellent spectral and temporal qualities by employing a novel technology, based on an externally injected gain-switched laser in conjunction with a non-linearly chirped grating. Using this technique, 3.5 ps optical pulses, exhibiting a time bandwidth product of 0.45, are generated, which are suitable for use in high-speed 80 Gb/s OTDM communications systems

Pulse source for 80 Gb/s systems using a gain-wwitched laser diode followed by a nonlinearly chirped grating

This work presents the generation of 3.5 ps pulses at a repetition rate of 10 GHz and the optimization of the pulse spectrum. The output pulses are near transform limited and have pulse pedestals that are virtually eliminated to 35 dB down from the peak of the pulse, thus providing a source suitable for use in 80 Gb/s OTDM systems

Optimized pulse source employing an externally injected gain-switched laser diode in conjunction with a nonlinearly chirped grating

In this paper, we demonstrate the generation of transform-limited short optical pulses, which display excellent spectral and temporal qualities by employing a novel technology, based on an externally injected gain-switched laser in conjunction with a nonlinearly chirped grating. Using this technique, 3.5-ps optical pulses exhibiting a time-bandwidth product (TBP) of 0.45 are generated, which are suitable for use in high-speed 80 Gb/s optical time-division multiplexing (OTDM) communications systems. The numerical integration of a set of rate equations using suitable parameters for the devices used in the experiments were carried out to further confirm the feasibility of the proposed method for developing an optimized pulse source for high-speed photonic systems

Discrete mode laser diodes with ultra narrow linewidth emission <3kHz

Ex-facet, free-running ultra-low linewidth (<3 kHz), single mode laser emission is demonstrated using low cost, regrowth-free ridge waveguide discrete mode Fabry-Perot laser diode chips

Pediatric Sacral Nerve Stimulator Explanation due to Complications or Cure: A Survival Analysis

Introduction Historically, there have been few treatment options for children with severe, refractory bladder and bowel dysfunction (BBD). Sacral neuromodulation (SNM) continues to show promising results in this challenging pediatric population with recalcitrant lower urinary tract symptoms. At our institution, we have begun offering explantation to those with persistent improvement after >6 months of having device turned off. We hypothesized that 1.) SNM explantation for cure increases with extended follow-up, and 2.) those explanted for cure would have improved symptoms and quality of life when compared to those explanted for complication. Materials & Methods We retrospectively reviewed all consecutive patients <18 years old who underwent SNM placements at our institution (2012-2017). We excluded those without the second stage procedure. Reasons for device explantation were categorized as: cure (resolution of symptoms with the device turned off for at least 6 months), or a complication (e.g. infection, need for MRI, or pain). Non-parametric tests and survival analysis were used for analysis to account for differential follow-up time. Of those explanted, surveys were electronically sent to assess BBD severity, and overall quality of life. Results Of 67 children who underwent a first stage procedure, 62 (92.5%) underwent a second stage procedure. 61 met inclusion criteria (68.9% female, 29.5 % with previous filum section, median age at implantation 10.3 years old). During follow-up (median 2.3 years), 12 patients (19.7 %) had the SNM exchanged/revised due to lead fracture/breakage and return of urinary symptoms. To date, 50 patients remain with their SNM implanted, and 11 have been explanted. Adjusting for follow-up time, the risk of explantation was 6.5% at 2 years (2.2% for cure, 4.3% for complications) (Figure 1). Explantation increased to 24.5% at 3 years (16.5% for cure, 8.0% for complications) and 40.4% at 4 years (32.4% for cure, 8.0% for complications). Questionnaires were collected on patients post explant (median 2.2 years), with improvement in those explanted for cure compared to complication (Figure 2). Discussion SNM explantation for cure is a novel concept previously not described in the literature. Limitations of this study include the relatively small numbers, and lack of objective data in the cohort that remains with SNM device implanted. Conclusion SNM is a safe, viable option for the pediatric patient with refractory bladder dysfunction. Furthermore, SNM explantation for cure is an option with increasing likelihood after two years

Is surgical antibiotic prophylaxis necessary for pediatric orchiopexy?

Introduction Surgeons frequently use surgical antibiotic prophylaxis (SAP), despite limited evidence to support its efficacy. Potential adverse events associated with antibiotic use include allergic reaction (including anaphylaxis), Clostridium difficile infection, and selecting for resistant bacteria. Surgical site infections (SSI) are very rare in patients undergoing clean pediatric urologic procedures. Current guidelines are unclear about the efficacy of surgical antibiotic prophylaxis for prevention of SSI in the pediatric population. Objective It was hypothesized that children who received SAP prior to orchiopexy would have no reduction in surgical site infection (SSI) risk but an increased risk of antibiotic-associated adverse events. Methods A retrospective cohort study was conducted of all males aged between 30 days and 18 years who underwent an orchiopexy (ICD-9 CM 62.5) in an ambulatory or observation setting from 2004 to 2015 using the Pediatric Health Information System database. Inpatients and those with concomitant procedures were excluded. Chi-squared or Fisher's exact tests were used to determine the association between SAP and allergic reaction (defined as a charge for epinephrine or ICD-9 diagnosis code for allergic reaction on the date of surgery) and any of the following within 30 days: SSI, hospital readmission or any repeat hospital encounter. Mixed effects logistic regression was performed, controlling for age, race, and insurance, and clustering of similar practice patterns by hospital. Results A total of 71,767 patients were included: median age was 4.6 years, 61.4% were white, and 49.3% had public insurance; 33.5% received SAP. Of these participants, 996/71,767 (1.4%) had a perioperative allergic reaction and <0.1% were diagnosed with an SSI. On mixed effects logistic regression, those who received SAP had 1.2 times the odds of a perioperative allergic reaction compared with those who did not receive SAP ( P = 0.005). Surgical antibiotic prophylaxis was not associated with decreased rates of SSI, lower hospital readmission, nor a lower chance of a repeat encounter within 30 days. Conclusions In patients undergoing orchiopexy, it was found that SAP did not reduce the risk of postoperative SSI, readmissions, or hospital visits. Patients who received SAP had significantly increased odds of perioperative allergic reaction. This demonstrated that the risks of SAP outweigh the benefits in children undergoing orchiopexy

Antimicrobial Activity of Metals and Metalloids

Competition shapes evolution. Toxic metals and metalloids have exerted selective pressure on life since the rise of the first organisms on the Earth, which has led to the evolution and acquisition of resistance mechanisms against them, as well as mechanisms to weaponize them. Microorganisms exploit antimicrobial metals and metalloids to gain competitive advantage over other members of microbial communities. This exerts a strong selective pressure that drives evolution of resistance. This review describes, with a focus on arsenic and copper, how microorganisms exploit metals and metalloids for predation and how metal- and metalloid-dependent predation may have been a driving force for evolution of microbial resistance against metals and metalloids.BFU2016-75425-P (70% FEDER), PID2020-112634GB-I0

Could recombinant insulin compounds contribute to adenocarcinoma progression by stimulating local angiogenesis?

Negative effects on the progression of adenocarcinomas by hyperinsulinaemia and the insulin analogue glargine (A21Gly,B31Arg,B32Arg human insulin) have recently been suggested. Most actions of this insulin analogue have hitherto been explained by direct stimulation of growth potential of neoplastic cells and by its IGF-1 related properties. However, insulin-stimulated angiogenesis could be an additional factor involved in tumour progression and clinical outcomes associated with cancer. Five types of human adenocarcinoma (breast, colon, pancreas, lung and kidney) were evaluated for the presence of insulin receptors (IRs) on angiogenic structures. In an in vitro angiogenesis assay, various commercially available insulin compounds were evaluated for their potential to increase capillary-like tube formation of human microvascular endothelial cells (hMVEC). Insulin compounds used were: human insulin, insulin lispro (B28Lys,B29Pro human insulin), insulin glargine and insulin detemir (B29Lys[e-tetradecanoyl],desB30 human insulin). Insulin receptors were found to be strongly expressed on the endothelium of microvessels in all evaluated adenocarcinomas, in addition to variable expression on tumour cells. Low or no detectable expression of IRs was seen on microvessels in extratumoral stroma. Incubation with commercially available insulin compounds increased capillary-like tube formation of hMVEC in vitro. Our results suggest that all tested insulin compounds may stimulate tumour growth by enhancing local angiogenesis. Future studies need to confirm the association between insulin therapy in type 2 diabetes and tumour progressio