A collocated finite volume scheme to solve free convection for general non-conforming grids

We present a new collocated numerical scheme for the approximation of the Navier-Stokes and energy equations under the Boussinesq assumption for general grids, using the velocity-pressure unknowns. This scheme is based on a recent scheme for the diffusion terms. Stability properties are drawn from particular choices for the pressure gradient and the non-linear terms. Numerical results show the accuracy of the scheme on irregular grids

Optical in-line biosensor for long-term continuous glucose monitoring and control in cell culture

Monitoring important process variables such as glucose in real-time is a major goal of bioprocess engineering, because it allows process control, which is not only essential for product quality and yield, but also important for the documentation and understanding of the production process and therefore relates to risk management [1]. This thesis deals with the development, thorough characterization and application of a disposable, optical in-line biosensor for monitoring and control of glucose in suspension cell culture. The in-line sensor, developed in this thesis, utilizes a commercially available oxygen sensor, that is coated with a crosslinked glucose oxidase (GOD) enzyme layer. The sensitivity of the sensor was tuned by the addition of a hydrophilic perforated diffusion membrane, to customize the dynamic range in order to meet the desired specifications. The biosensor was modelled in order to gain crucial insights into the internal concentration profile of the enzyme deactivating by-product hydrogen peroxide. The one-dimensional biosensor model revealed that the turnover rate of the enzyme GOD plays a crucial role for the functional stability of the biosensor in combination with the internal hydrogen peroxide accumulation. This insight was utilized to optimize the glucose biosensor for long-term continuous glucose monitoring over typical cell culture durations. A comprehensive biosensor characterization was performed to study the applicability and limitations of the developed biosensor for cell culture. Hereby, it was demonstrated that the sensor is sterilisable with beta, gamma and UV irradiation and is only subject to minor cross sensitivity to oxygen in combination with a reference oxygen sensor. The presented optical biosensor provides information in real-time and was therefore used in combination with a reference oxygen sensor to control the glucose level continuously in CHO cell culture with an automated feeding systems. It was found that the sialylation of the hyperglycosylated erythropoietin analog Darbepoetin alfa, could be significantly increased through continuous glucose feeding by retaining a high glucose level during the production phase of the cell culture. Therefore, the developed biosensor provides a valuable tool for optimizing culture conditions in biotechnological applications

Characterization of an internal slope movement structure by hydrogeophysical surveying

International audienceA hydrogeophysical study was carried out by a water controlled injection within a landslide situated on an active part of the La Clapière landslide foot (Alpes Maritimes, France). Coupling of both real-time geophysical and hydrological follow ups allowed the representation and quantification of the surface water drainage in space and time within the slipped mass. Thus, 30% of the injected water is quickly drained by a complex slipping surface meanly situated at 10-m depth. The transit time between injection and outflow of the water allowed an overloading of about 10 m3 (i.e. 10 tons) comparable with classical rain events in the area. This weight and the associated interstitial pressures increase have not led to any movements asking for the origin of the water volumes which could induce destabilizations. This experiment enabled an accurate redefinition of the internal slope structure and the understanding of the dynamics of the slipped mass with a surface hydraulic request

Geophysical survey to estimate the 3D sliding surface and the 4D evolution of the water pressure on part of a deep seated landslide

International audienceGeophysical surveys were conducted on the very unstable front part of the La Clapière landslide in the French Alps (Alpes Maritimes). The electrical resistivity survey was carried out to obtain, for the first time on this deep-seated landslide, 3D information on the slipping surface and the vertical drained faults. Moreover, we planned to follow within time (6 months) the evolution of the saturated zones (presence of gravitational water) and their percolation into the shearing zones. Our 4D results showed the importance of the complex water channelization within the slope and relation to geological discontinuities

The one-hour post-load plasma glucose predicts progression to prediabetes in a multiethnic cohort of obese youths

One-hour post-load hyperglycemia has been proposed as an independent predictor of type 2 diabetes in adults. We examined whether 1-hour plasma glucose (1hPG) during an oral glucose tolerance test (OGTT) can predict changes in the glucose tolerance status in a multiethnic cohort of youths with normal glucose tolerance (NGT)

Experimental analysis of groundwater flow through a landslide slip surface using natural and artificial water chemical tracers.

International audienceArtificial and natural tracer tests combined with high accurate electronic distancemeter measurements are conducted on a small landslide with a well known slip surface geometry. Outflow yields and chemical contents are monitored for all the experiment duration and they analyzed to estimate the slip surface hydraulic parameters. The main result is that the slip surface acts as a drain for groundwater flows that evacuates interstitial pressures in the slope and brings the sliding mass to be more stable one

Continuous optical in-line glucose monitoring and control in CHO cultures contributes to enhanced metabolic efficiency while maintaining darbepoetin alfa product quality

Great efforts are directed towards improving productivity, consistency and quality of biopharmaceutical processes and products. One particular area is the development of new sensors for continuous monitoring of critical bioprocess parameters by using online or in-line monitoring systems. Recently, we developed a glucose biosensor applicable in single-use, in-line and long-term glucose monitoring in mammalian cell bioreactors. Now, we integrated this sensor in an automated glucose monitoring and feeding system capable of maintaining stable glucose levels, even at very low concentrations. We compared this fed-batch feedback system at both low (< 1 mM) and high (40 mM) glucose levels with traditional batch culture methods, focusing on glycosylation and glycation of the recombinant protein darbepoetin alfa (DPO) produced by a CHO cell line. We evaluated cell growth, metabolite and product concentration under different glucose feeding strategies and show that continuous feeding, even at low glucose levels, has no harmful effects on DPO quantity and quality. We conclude that our system is capable of tight glucose level control throughout extended bioprocesses and has the potential to improve performance where constant maintenance of glucose levels is critical. © 2021 The Authors. Biotechnology Journal published by Wiley-VCH Gmb

A randomised non-inferiority controlled trial of a single versus a four intradermal sterile water injection technique for relief of continuous lower back pain during labour

Background: Almost one third of women suffer continuous lower back pain during labour. Evidence from three systematic reviews demonstrates that sterile water injections (SWI) provide statistically and clinically significant pain relief in women experiencing continuous lower back pain during labour. The most effective technique to administer SWI is yet to be determined. Therefore, the aim of this study is to determine if the single injection SWI technique is no less effective than the routinely used four injection SWI method in reducing continuous lower back pain during labour.Methods/design: The trial protocol was developed in consultation with an interdisciplinary team of clinical researchers. We aim to recruit 319 women presenting at term, seeking analgesia for continuous severe lower back pain during labour. Participants will be recruited from two major maternity hospitals in Australia. Randomised participants are allocated to receive a four or single intradermal needle SWI technique. The primary outcome is the change in self-reported pain measured by visual analogue scale at baseline and thirty minutes post intervention. Secondary outcomes include VAS change scores at 10, 60, 90 and 120 min, analgesia use, mode of birth and maternal satisfaction.Statistical analysis: Sample size was calculated to achieve 90% power at an alpha of 0.025 to detect a non-inferiority margin of ≤ 1 cm on the VAS, using a one-sided, two-sample t-test. Baseline demographic and clinical characteristics will be analysed for comparability between groups. Differences in primary (VAS pain score) and secondary outcomes between groups will be analysed by intention to treat and per protocol analysis using Student's t-test and ANOVA.Conclusion: This study will determine if a single intradermal SWI technique is no less effective than the routinely used four injection technique for lower back pain during labour. The findings will allow midwives to offer women requesting SWI during labour an evidence-based alternative technique more easily administered by staff and accepted by labouring women. Trial Registration: ACTRN12609000964213

Domain wall pinning and dislocations: Investigating magnetite deformed under conditions analogous to nature using transmission electron microscopy

In this study, we deformed samples cut from a single magnetite octahedron and used transmission electron microscopy (TEM) and magnetic measurements to experimentally verify earlier computational models of magnetic domain wall pinning by dislocations and to better understand the nature of dislocations in magnetite. Dislocations in magnetite have been of interest for many decades because they are often cited as a likely source of stable thermoremanent magnetizations in larger multidomain (MD) magnetite grains, so a better understanding of dislocation effects on coercivity in MD magnetite is crucial. TEM imaging shows, for the first time, domain walls sweeping through the magnetite sample and being pinned at dislocations. In agreement with theory, these findings demonstrate that domain walls are more strongly pinned at networks of dislocations than at single dislocations and that domain walls pinned at longer dislocations have higher microcoercivities than those pinned at shorter dislocations. This experimentally illustrates the ability of dislocations to increase the coercivity of larger multidomain magnetite grains. The observed values for microcoercivity and bulk coercivity are in reasonable agreement with theoretical calculations. Burgers vectors were determined for some dislocations to verify that they were in keeping with expected dislocation orientations. The dislocations were found to be primarily located on close-packed {111} planes within the magnetite. Deformation caused only a minor change in bulk coercivity, but first-order reversal curve diagrams show populations with increased coercivity not visible in hysteresis loops.The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC grant agreement 320750. The Institute for Rock Magnetism and LacCore are supported by the NSF EAR Instrumentation and Facilities Program and by the University of Minnesota, Earth Sciences Division, National Science Foundation. To obtain the data used for this paper, please contact A.K.L. This work was funded by EAR-0810085 to J.M.F., by EAR-0810252 to A.J.N., and by a Geological Society of America grant to A.K.L. This is IRM publication 1406.This is the final published version. It first appeared at http://onlinelibrary.wiley.com/doi/10.1002/2014JB011335/abstract?rememberMePresent=false