Formation and mobilization of methylmercury across natural and experimental sulfur deposition gradients

We investigated the influence of sulfate (SO42-) deposition and concentrations on the net formation and solubility of methylmercury (MeHg) in peat soils. We used data from a natural sulfate deposition gradient running 300 km across southern Sweden to test the hypothesis posed by results from an experimental field study in northern Sweden: that increased loading of SO42- both increases net MeHg formation and redistributes methylmercury (MeHg) from the peat soil to its porewater. Sulfur concentrations in peat soils correlated positively with MeHg concentrations in peat porewater, along the deposition gradient similar to the response to added SO42- in the experimental field study. The combined results from the experimental field study and deposition gradient accentuate the multiple, distinct and interacting roles of SO42- deposition in the formation and redistribution of MeHg in the environment. (c) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Opposing spatial trends in methylmercury and total mercury along a peatland chronosequence trophic gradient

Peatlands are abundant elements of boreal landscapes where inorganic mercury (IHg) can be transformed into bioaccumulating and highly toxic methylmercury (MeHg). We studied fifteen peatlands divided into three age lasses (young, intermediate and old) along a geographically constrained chronosequence to determine the role of biogeochemical factors and nutrient availability in controlling the formation of MeHg. In the 10 cm soil layer just below the average annual growing season water table, concentrations of MeHg and %MeHg (of total Hg) were higher in younger, more mesotrophic peatlands than in older, more oligotrophic peatlands. In contrast, total mercury (THg) concentrations were higher in the older peatlands. Partial least squares (PLS) analysis indicates that the net MeHg production was positively correlated to trophic demands of vegetation and an increased availability of potential electron acceptors and donors for Hg methylating microorganisms. An important question for further studies will be to elucidate why there is less THg in the younger peatlands compared to the older peatlands, even though the age of the superficial peat itself is similar for all sites. We hypothesize that ecosystem features which enhance microbial processes involved in Hg methylation also promote Hg reduction that makes previously deposited Hg more available for evasion back to the atmosphere. (C) 2020 Elsevier B.V. All rights reserved

A scalable adenovirus production process, from cell culture to purified bulk

Adenovirus (AdV) vectors are commonly used in cancer gene therapy trials, evaluated in gene therapy and used as vaccines for various diseases. AdV vectors are well studied and are suitable as vaccine vectors due to their ability to infect different cell types, remain episomal and produce stable high titer material. Manufacturing of safe and efficacious clinical-grade virus relies on a scalable and cost-effective production process. In this study, we have combined experimental work and process economy calculations, from AdV production in cell culture to purified bulk product up to 10L scale. An efficient and scalable process for AdV production was developed by evaluation of each process step. The most studied vector is serotype 5, making this a suitable system for process development of AdV vectors. Human AdV5 expressing the green fluorescent protein (GFP) was used for process development. First, suspension HEK 293 cells adapted to serum-free cell culture medium were optimized for AdV production and evaluated in different single use bioreactor systems. Tween 20 was used for cell lysis as a replacement for the traditionally used Triton X-100 (now on the Authorization list (Annex XIV) of REACH, the regulation on Registration, Evaluation, Authorization and restriction of Chemicals). A residual Tween 20 assay with low detection limit was set-up. Filters and conditions for clarification, concentration and buffer exchange by tangential flow filtration were optimized. Anion exchange based capture step alternatives were compared, including different chromatography resins and membrane formats. Finally, core bead technology was evaluated as an alternative to size exclusion chromatography for the polishing step before the final formulation. Analytical methods for virus titer are challenging and depend on purity and quality of the sample. For total virus titer, qPCR and HPLC methods were used. Furthermore, a method based on surface plasmon resonance (Biacore) was developed for analysis of adenovirus titer. For infectious virus titer, we have used a cell based assay with automatic image analysis. Based on analytical data different downstream process alternatives were compared regarding load capacity, recovery and purity and we propose a robust and scalable process with a favorable process economy. Please click Additional Files below to see the full abstract

Biogeochemical influences on net methylmercury formation proxies along a peatland chronosequence

A geographically constrained chronosequence of peatlands divided into three age classes (young, intermediate and old) was used to explore the role of biogeochemical influences, including electron donors and acceptors as well as chemical speciation of inorganic mercury (Hg(II)), on net formation of methylmercury (MeHg) as approximated by the fraction of MeHg to total mercury (THg) in the peat soil. We hypothesized that removing vascular plants would reduce availability of electron donors and thus net MeHg formation. However, we found no effect of the vascular plant removal. The sum of the potential electron donors (acetate, lactate, propionate and oxalate), the electron donation proxy organic C/Organic N, and the potential electron acceptors (Fe(III), Mn and sulfate) in porewater all showed significant correlations with the net MeHg formation proxies in peat soil (MeHg concentration and %MeHg of THg). Thus differences in both electron donor and acceptor availability may be contributing to the pattern of net MeHg formation along the chronosequence. In contrast, Hg(II) concentrations in peat porewater showed small differences along the gradient. A chemical speciation model successfully predicted the solubility of Hg and MeHg in the porewater. The modeling pointed to an enhanced concentration of Hg-polysulfide species in the younger peatlands as a potential factor behind increased Hg(II) solubility and methylation in the more nutrient-rich peatlands. This work contributes to the understanding of Hg and MeHg cycling in peatlands which can help guide mitigation measures to reduce aquatic MeHg biomagnification in peatland dominated landscapes. (C) 2021 The Authors. Published by Elsevier Ltd

Gear Geometry for Reduced and Robust Transmission Error and Gearbox Noise

Gear geometry was optimized for decreased transmission error in order to reduce gearbox noise. Robustness with respect to gear deviations and varying torque was considered in order to find a gear geometry giving low noise in the appropriate torque interval despite deviations from the nominal geometry due to manufacturing tolerances. Static and dynamic transmission error as well as noise and housing vibration were measured using a gear test rig. The correlation between dynamic transmission error, housing vibration, and noise was investigated. In speed sweeps from 500 to 2500 rpm at constant torque, no correlation was found between dynamic transmission error and noise. Static transmission error seems to be the excitation of dynamic transmission error as well as housing vibration and noise, but different natural frequencies for different degrees of freedom of the dynamic system consisting of gears shafts, bearings, and housing lead to lack of correlation between dynamic transmission error and noise.QC 2010092

Gear Noise and Vibration : A Literature Survey

This paper is a survey of the literature on gear noise and vibration. It is divided into three parts, “Transmission error”, “Dynamic models” and “Noise and vibration measurement”. Transmission error (TE) is considered to be an important excitation mechanism for gear noise and vibration. The definition of transmission error is “The difference between the actual position of the output gear and the position it would occupy if the gear drive were perfectly conjugate”. Dynamic models of the system consisting of gears, shafts, bearings and gearbox casing are useful in order to understand and predict the dynamical behaviour of a gearbox. Noise and vibration measurement and signal analysis are important tools when experimentally investigating gear noise because gears create noise at specific frequencies, related to number of teeth and the rotational speed of the gear.QC 2010092

Gear Noise and Vibration : A Literature Survey

This paper is a survey of the literature on gear noise and vibration. It is divided into three parts, “Transmission error”, “Dynamic models” and “Noise and vibration measurement”. Transmission error (TE) is considered to be an important excitation mechanism for gear noise and vibration. The definition of transmission error is “The difference between the actual position of the output gear and the position it would occupy if the gear drive were perfectly conjugate”. Dynamic models of the system consisting of gears, shafts, bearings and gearbox casing are useful in order to understand and predict the dynamical behaviour of a gearbox. Noise and vibration measurement and signal analysis are important tools when experimentally investigating gear noise because gears create noise at specific frequencies, related to number of teeth and the rotational speed of the gear.QC 2010092

Gear Test Rig for Noise and Vibration Testing of Cylindrical Gears

Gear noise is sometimes the dominating noise in commercial vehicles. Noise testing of complete gearboxes is very time-consuming and expensive. A test rig has been designed for testing gears under controlled conditions. The test rig is of the recirculating power type. Finite element analysis has been used to predict the dynamical properties of the gear test rig. Experimental modal analysis has been carried out on the gearbox housing to verify the theoretical predictions of natural frequencies. The test rig can be used for noise and vibration testing of gears with different manufacturing errors and different design parameters. In addition to noise testing, the rig can be used for gear life testing and measurement of efficiency.QC 2010092

Gearbox noise : Correlation with transmission error and influence of bearing preload

The five appended papers all deal with gearbox noise and vibration. The first paper presents a review of previously published literature on gearbox noise and vibration. The second paper describes a test rig that was specially designed and built for noise testing of gears. Finite element analysis was used to predict the dynamic properties of the test rig, and experimental modal analysis of the gearbox housing was used to verify the theoretical predictions of natural frequencies. In the third paper, the influence of gear finishing method and gear deviations on gearbox noise is investigated in what is primarily an experimental study. Eleven test gear pairs were manufactured using three different finishing methods. Transmission error, which is considered to be an important excitation mechanism for gear noise, was measured as well as predicted. The test rig was used to measure gearbox noise and vibration for the different test gear pairs. The measured noise and vibration levels were compared with the predicted and measured transmission error. Most of the experimental results can be interpreted in terms of measured and predicted transmission error. However, it does not seem possible to identify one single parameter, such as measured peak-to-peak transmission error, that can be directly related to measured noise and vibration. The measurements also show that disassembly and reassembly of the gearbox with the same gear pair can change the levels of measured noise and vibration considerably. This finding indicates that other factors besides the gears affect gear noise. In the fourth paper, the influence of bearing endplay or preload on gearbox noise and vibration is investigated. Vibration measurements were carried out at torque levels of 140 Nm and 400 Nm, with 0.15 mm and 0 mm bearing endplay, and with 0.15 mm bearing preload. The results show that the bearing endplay and preload influence the gearbox vibrations. With preloaded bearings, the vibrations increase at speeds over 2000 rpm and decrease at speeds below 2000 rpm, compared with bearings with endplay. Finite element simulations show the same tendencies as the measurements. The fifth paper describes how gearbox noise is reduced by optimizing the gear geometry for decreased transmission error. Robustness with respect to gear deviations and varying torque is considered in order to find a gear geometry giving low noise in an appropriate torque range despite deviations from the nominal geometry due to manufacturing tolerances. Static and dynamic transmission error, noise, and housing vibrations were measured. The correlation between dynamic transmission error, housing vibrations and noise was investigated in speed sweeps from 500 to 2500 rpm at constant torque. No correlation was found between dynamic transmission error and noise. Static loaded transmission error seems to be correlated with the ability of the gear pair to excite vibration in the gearbox dynamic system.QC 2010092

Automatiserat installationsskript för Sopimus Pro

Uppgiften för arbetet var att utveckla ett automatiserat installationsskript som automatiskt och utan användarens inblandning installerar Sopimus Pro-systemet på en dator med Windows som operativsystem. Sopimus Pro är flaggskeppsprodukten för Rediteq Ab, som utvecklar utbildningsmjukvara för utbildare i Finland. Det färdiga skriptet installerar alla nödvändiga komponenter i tur och ordning samt gör alla nödvändiga konfigurationer som krävs för att systemet ska fungerra. Detta arbete behandlar hela installationsprocessen från början till slut, samt grunderna för hur en automatisk installation går till med hjälp av användning av s.k. svarsfiler. Skriptet använder sig av batchfiler som körs med CMD eller komandopromten. Inom installationen används även en automatiseringsapplikation vid namnet AutoIt. Som anställd hos Rediteq Ab har jag redan haft användning av skriptet inom mina egna arbetsuppgifter. Slutresultatet är ett automatiserat skript som klarar av att installera Sopimus Pro-systemet snabbare än en installation som görs manuellt.The task for this thesis was to develop an automated and unattended install script for installation of the Sopimus Pro-system on a computer with Windows as its operating system. Sopimus Pro is the flagship product for Rediteq Ltd, a software development company focusing on solutions for education providers in Finland. The complete script installs all the components required for Sopimus Pro to run. This thesis deals with the whole installation process from start to finish. It also covers the basics of an automated install and the usage of answer files. The script uses batch files which are run with CMD or the Command Prompt. An automation application named AutoIt was used to solve various tasks during the installation. As an employee at Rediteq Ltd I have already had the chance to use my script in my work tasks. The end result is an automated script which is capable of installing the Sopimus Pro-system by itself faster than a user would do manually