Degradation Kinetics of Lignocellulolytic Enzymes in a Biogas Reactor Using Quantitative Mass Spectrometry

The supplementation of lignocellulose-degrading enzymes can be used to enhance the performance of biogas production in industrial biogas plants. Since the structural stability of these enzyme preparations is essential for efficient application, reliable methods for the assessment of enzyme stability are crucial. Here, a mass-spectrometric-based assay was established to monitor the structural stability of enzymes, i.e., the structural integrity of these proteins, in anaerobic digestion (AD). The analysis of extracts of Lentinula edodes revealed the rapid degradation of lignocellulose-degrading enzymes, with an approximate half-life of 1.5 h. The observed low structural stability of lignocellulose-degrading enzymes in AD corresponded with previous results obtained for biogas content. The established workflow can be easily adapted for the monitoring of other enzyme formulations and provides a platform for evaluating the effects of enzyme additions in AD, together with a characterization of the biochemical methane potential used in order to determine the biodegradability of organic substrates

Antibiotic prophylaxis for selected gynecologic surgeries

BackgroundAntibiotic prophylaxis for surgery is commonly used and is recommended by multiple organizations.ObjectiveTo critically review gynecology‐specific data regarding surgical antibiotic prophylaxis in selected benign gynecologic surgeries.Search strategyMEDLINE and Cochrane databases were searched from inception to July 2010.Selection criteriaRandomized controlled trials of benign vaginal, cervical, transcervical, abdominal, or laparoscopic procedures other than hysterectomy comparing prophylactic antibiotic use with placebo or with another antibiotic. Outcomes of interest were postoperative infections, additional treatments, and adverse events.Data collection and analysisIn total, 19 trials met the inclusion criteria. Studies were individually assessed for methodologic quality, then grouped by procedure and evaluated for evidence quality.Main resultsThere was no difference in infectious outcome for loop electrosurgical excision, hysteroscopic ablation, or laparoscopy, although evidence quality was poor. Fair evidence supports antibiotic prophylaxis for suction curettage or laparotomy. There were insufficient data regarding vaginal surgery prophylaxis.ConclusionAntibiotic prophylaxis may be beneficial in first‐trimester suction curettage and laparotomy. No advantage was found for loop electrosurgical excision, hysteroscopy, or laparoscopic gynecologic surgery. Newer procedures and vaginal surgery lack research and merit study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135267/1/ijgo10.pd

Suppression of Penning discharges between the KATRIN spectrometers

The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective electron (anti)-neutrino mass with a sensitivity of 0.2eV/c$^{2}$ by precisely measuring the endpoint region of the tritium β-decay spectrum. It uses a tandem of electrostatic spectrometers working as magnetic adiabatic collimation combined with an electrostatic (MAC-E) filters. In the space between the pre-spectrometer and the main spectrometer, creating a Penning trap is unavoidable when the superconducting magnet between the two spectrometers, biased at their respective nominal potentials, is energized. The electrons accumulated in this trap can lead to discharges, which create additional background electrons and endanger the spectrometer and detector section downstream. To counteract this problem, “electron catchers” were installed in the beamline inside the magnet bore between the two spectrometers. These catchers can be moved across the magnetic-flux tube and intercept on a sub-ms time scale the stored electrons along their magnetron motion paths. In this paper, we report on the design and the successful commissioning of the electron catchers and present results on their efficiency in reducing the experimental background