Seasonal Variability of Forces Controlling Sedimentation in the Sundarbans National Forest, Bangladesh

Southwest Bangladesh, located on the Ganges-Brahmaputra-Meghna delta, is experiencing the impacts of sea level rise (SLR) due to processes at both the local and global scale. In particular, regional alterations of the hydrodynamic network, due to embankment construction, have drastically altered effective SLR, placing millions of inhabitants at risk of prolonged inundation, and threatening the world’s largest continuous mangrove stand, the Sundarbans National Forest (SNF). In order to effectively employ landscape recovery solutions, an understanding of local sediment transport and deposition is critical. This field-based study investigates the sediment dynamics between the mangrove platform and tidal channels of the SNF using data from a variety of instruments and sediment samples collected within a forested sub-basin (∼20 km2) fed by a major tidal channel. We observe profound seasonal variability within the sub-basin, with the wet season exhibiting a deeper and longer inundation of the mangrove platform and greater suspended sediment concentrations (SSC). Further, there exists a trend of decreasing SSC and median grain size from the perimeter of the SNF to the interior, and decreasing SSC from the tidal channel to the platform at both locations. We project seasonal platform sedimentation rates ranging from 0.17 ± 0.16 cm in the dry season to 1.8 ± 0.35 cm in the wet season. Importantly, the annual deposition rate measured at either location is sufficiently rapid to keep pace with observed rates of effective SLR published in other studies (∼1.0–1.7 cm/year). Based on our results, it appears that many controls on sedimentation are both covariant and of similar importance to land aggradation in the SNF. While inundation depth and frequency will likely increase under future SLR scenarios, sediment supply is threatened by India’s proposed River Linking Project, which could decrease the sediment loads of the Ganges and Brahmaputra Rivers by as much as 75 and 25%, respectively. These rivers provide the sediment for the entire delta, and we predict that with decreasing SSC, some regions—particularly interior sediment-depleted regions—may begin to deteriorate and become submerged, including within the SNF

PHARAO Laser Source Flight Model: Design and Performances

In this paper, we describe the design and the main performances of the PHARAO laser source flight model. PHARAO is a laser cooled cesium clock specially designed for operation in space and the laser source is one of the main sub-systems. The flight model presented in this work is the first remote-controlled laser system designed for spaceborne cold atom manipulation. The main challenges arise from mechanical compatibility with space constraints, which impose a high level of compactness, a low electric power consumption, a wide range of operating temperature and a vacuum environment. We describe the main functions of the laser source and give an overview of the main technologies developed for this instrument. We present some results of the qualification process. The characteristics of the laser source flight model, and their impact on the clock performances, have been verified in operational conditions.Comment: Accepted for publication in Review of Scientific Instrument

Modular ATR FT-IR microreactor chip for optimizing reaction conditions

A silicon chip for attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopy in combination with a modular PDMS herringbone mixer and a microreactor has been successfully fabricated and tested. The modular design allows the chip to be used for a variety of reactions. A model synthesis of 1-butyl-2,5-dimethyl-1H-pyrrole from hexane-2,5-dione with 1-butylamine has been performed on chip. When plotting the natural logarithm of the peak area corresponding to the ketone stretch vibration at 1710cm-1, against the residence time, a linear curve can be fitted, suggesting this step to be a first order reaction

Integrated microfluidic biosensing platform for simultaneous confocal microscopy and electrophysiological measurements on bilayer lipid membranes and ion channels

Combining high-resolution imaging and electrophysiological recordings is key for various types of experimentation on lipid bilayers and ion channels. Here, we propose an integrated biosensing platform consisting of a microfluidic cartridge and a dedicated chip-holder to conduct such dual measurements on suspended lipid bilayers, in a user-friendly manner. To illustrate the potential of the integrated platform, we characterize lipid bilayers in terms of thickness and fluidity while simultaneously monitoring single ion channel currents. For that purpose, POPC lipid bilayers are supplemented with a fluorescently-tagged phospholipid (NBD-PE, 1% mol) for Fluorescence Recovery After Photobleaching (FRAP) measurements and a model ion channel (gramicidin, 1 nM). These combined measurements reveal that NBD-PE has no effect on the lipid bilayer thickness while gramicidin induces thinning of the membrane. Furthermore, the presence of gramicidin does not alter the lipid bilayer fluidity. Surprisingly, in lipid bilayers supplemented with both probes, a reduction in gramicidin open probability and lifetime is observed compared to lipid bilayers with gramicidin only, suggesting an influence of NBD-PE on the gramicidin ion function. Altogether, our proposed microfluidic biosensing platform in combination with the herein presented multi-parametric measurement scheme paves the way to explore the interdependent relationship between lipid bilayer properties and ion channel function

Proton acceleration by irradiation of isolated spheres with an intense laser pulse

We report on experiments irradiating isolated plastic spheres with a peak laser intensity of 2-3 x 10(20) W cm(-2). With a laser focal spot size of 10 mu m full width half maximum (FWHM) the sphere diameter was varied between 520 nm and 19.3 mu m. Maximum proton energies of similar to 25 MeV are achieved for targets matching the focal spot size of 10 mu m in diameter or being slightly smaller. For smaller spheres the kinetic energy distributions of protons become nonmonotonic, indicating a change in the accelerating mechanism from ambipolar expansion towards a regime dominated by effects caused by Coulomb repulsion of ions. The energy conversion efficiency from laser energy to proton kinetic energy is optimized when the target diameter matches the laser focal spot size with efficiencies reaching the percent level. The change of proton acceleration efficiency with target size can be attributed to the reduced cross-sectional overlap of subfocus targets with the laser. Reported experimental observations are in line with 3D3V particle in cell simulations. They make use of well-defined targets and point out pathways for future applications and experiments.DFG via the Cluster of Excellence Munich-Centre for Advanced Photonics (MAP) Transregio SFB TR18NNSA DE-NA0002008Super-MUC pr48meIvo CermakCGC Instruments in design and realization of the Paul trap systemIMPRS-APSLMUexcellent Junior Research FundDAAD|ToIFEEuropean Union's Horizon research and innovation programme 633053Physic

A Mass Spectrometry-Based Approach for Mapping Protein Subcellular Localization Reveals the Spatial Proteome of Mouse Primary Neurons

We previously developed a mass spectrometry-based method, Dynamic Organellar Maps, for the determination of protein subcellular localisation, and the identification of translocation events in comparative experiments. The use of metabolic labelling for quantification (SILAC) renders the method best suited to cells grown in culture. Here we have adapted the workflow to both label-free quantification (LFQ) and chemical labelling/multiplexing strategies (Tandem Mass Tagging, TMT). Both new methods are highly effective for generation of organellar maps and capture of protein translocations. Furthermore, application of label-free organellar mapping to acutely isolated mouse primary neurons provided subcellular localisation and copy number information for over 8,000 proteins, allowing a detailed analysis of organellar organisation. Our study extends the scope of Dynamic Organellar Maps to any cell type or tissue, and also to high throughput screening.This work was funded by the German Research Foundation (DFG/Gottfried Wilhelm Leibniz Prize MA 1764/2-1), the Louis-Jeantet Foundation, the Max Planck Society for the Advancement of Science, a Wellcome Trust Senior Clinical Research Fellowship 108070/Z/15/Z (to M.P.W.), and a strategic award to Cambridge Institute for Medical Research from the Wellcome Trust (100140)

The Role of Cathepsin D in the Pathophysiology of Heart Failure and its Potentially Beneficial Properties:a translational approach

Aims: Cathepsin D is a ubiquitous lysosomal protease that is primarily secreted due to oxidative stress. The role of circulating cathepsin D in heart failure (HF) is unknown. The aim of this study is to determine the association between circulating cathepsin D levels and clinical outcomes in patients with HF and to investigate the biological settings that induce the release of cathepsin D in HF. Methods and results: Cathepsin D levels were studied in 2174 patients with HF from the BIOSTAT-CHF index study. Results were validated in 1700 HF patients from the BIOSTAT-CHF validation cohort. The primary combined outcome was all-cause mortality and/or HF hospitalizations. Human pluripotent stem cell-derived cardiomyocytes were subjected to hypoxic, pro-inflammatory signalling and stretch conditions. Additionally, cathepsin D expression was inhibited by targeted short hairpin RNAs (shRNA). Higher levels of cathepsin D were independently associated with diabetes mellitus, renal failure and higher levels of interleukin-6 and N-terminal pro-B-type natriuretic peptide (P < 0.001 for all). Cathepsin D levels were independently associated with the primary combined outcome [hazard ratio (HR) per standard deviation (SD): 1.12; 95% confidence interval (CI) 1.02–1.23], which was validated in an independent cohort (HR per SD: 1.23, 95% CI 1.09–1.40). In vitro experiments demonstrated that human stem cell-derived cardiomyocytes released cathepsin D and troponin T in response to mechanical stretch. ShRNA-mediated silencing of cathepsin D resulted in increased necrosis, abrogated autophagy, increased stress-induced metabolism, and increased release of troponin T from human stem cell-derived cardiomyocytes under stress. Conclusions: Circulating cathepsin D levels are associated with HF severity and poorer outcome, and reduced levels of cathepsin D may have detrimental effects with therapeutic potential in HF

Dynamic loading of human engineered heart tissue enhances contractile function and drives a desmosome-linked disease phenotype

The role that mechanical forces play in shaping the structure and function of the heart is critical to understanding heart formation and the etiology of disease but is challenging to study in patients. Engineered heart tissues (EHTs) incorporating human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes have the potential to provide insight into these adaptive and maladaptive changes. However, most EHT systems cannot model both preload (stretch during chamber filling) and afterload (pressure the heart must work against to eject blood). Here, we have developed a new dynamic EHT (dyn-EHT) model that enables us to tune preload and have unconstrained contractile shortening of >10%. To do this, three-dimensional (3D) EHTs were integrated with an elastic polydimethylsiloxane strip providing mechanical preload and afterload in addition to enabling contractile force measurements based on strip bending. Our results demonstrated that dynamic loading improves the function of wild-type EHTs on the basis of the magnitude of the applied force, leading to improved alignment, conduction velocity, and contractility. For disease modeling, we used hiPSC-derived cardiomyocytes from a patient with arrhythmogenic cardiomyopathy due to mutations in the desmoplakin gene. We demonstrated that manifestation of this desmosome-linked disease state required dyn-EHT conditioning and that it could not be induced using 2D or standard 3D EHT approaches. Thus, a dynamic loading strategy is necessary to provoke the disease phenotype of diastolic lengthening, reduction of desmosome counts, and reduced contractility, which are related to primary end points of clinical disease, such as chamber thinning and reduced cardiac output