Performance Study of MXene/Carbon Nanotube Composites for Current Collector‐ and Binder‐Free Mg–S Batteries

The realization of sustainable and cheap Mg-S batteries depends on significant improvements in cycling stability. Building on the immense research on cathode optimization from Li-S batteries, for the first time a beneficial role of MXenes for Mg-S batteries is reported. Through a facile, low-temperature vacuum-filtration technique, several novel current collector- and binder-free cathode films were developed, with either dipenthamethylene thiuram tetrasulfide (PMTT) or $S_{8}$ nanoparticles as the source of redox-active sulfur. The importance of combining MXene with a high surface area co-host material, such as carbon nanotubes, was demonstrated. A positive effect of MXenes on the average voltage and reduced self-discharge was also discovered. Ascribed to the rich polar surface chemistry of $Ti_{3}C_{2}T_{x}$ MXene, an almost doubling of the discharge capacity (530 vs. 290 mA h $g^{−1}$) was achieved by using MXene as a polysulfide-confining interlayer, obtaining a capacity retention of 83 % after 25 cycles

Cleavage of the urokinase receptor (uPAR) on oral cancer cells: Regulation by transforming growth factor - beta1 (TGF-beta1) and potential effects on migration and invasion

Source at https://doi.org/10.1186/s12885-017-3349-7 Background: Urokinase plasminogen activator (uPA) receptor (uPAR) is up-regulated at the invasive tumour front of human oral squamous cell carcinoma (OSCC), indicating a role for uPAR in tumour progression. We previously observed elevated expression of uPAR at the tumour-stroma interface in a mouse model for OSCC, which was associated with increased proteolytic activity. The tumour microenvironment regulated uPAR expression, as well as its glycosylation and cleavage. Both full-length- and cleaved uPAR (uPAR (II-III)) are involved in highly regulated processes such as cell signalling, proliferation, migration, stem cell mobilization and invasion. The aim of the current study was to analyse tumour associated factors and their effect on uPAR cleavage, and the potential implications for cell proliferation, migration and invasion. Methods: Mouse uPAR was stably overexpressed in the mouse OSCC cell line AT84. The ratio of full-length versus cleaved uPAR as analysed by Western blotting and its regulation was assessed by addition of different protease inhibitors and transforming growth factor - β 1(TGF- β 1). The role of uPAR cleavage in cell proliferation and migration was analysed using real-time cell analysis and invasion was assessed using the myoma invasion model. Results: We found that when uPAR was overexpressed a proportion of the receptor was cleaved, thus the cells presented both full-length uPAR and uPAR (II-III). Cleavage was mainly performed by serine proteases and urokinase plasminogen activator (uPA) in particular. When the OSCC cells were stimulated with TGF- β 1, the production of the uPA inhibitor PAI-1 was increased, resulting in a reduction of uPAR cleavage. By inhibiting cleavage of uPAR, cell migration was reduced, and by inhibiting uPA activity, invasion was reduced. We could also show that medium containing soluble uPAR (suPAR), and cleaved soluble uPAR (suPAR (II-III)), induced migration in OSCC cells with low endogenous levels of uPAR. Conclusions: These results show that soluble factors in the tumour microenvironment, such as TGF- β 1, PAI-1 and uPA, can influence the ratio of full length and uPAR (II-III) and thereby potentially effect cell migration and invasion. Resolving how uPAR cleavage is controlled is therefore vital for understanding how OSCC progresses and potentially provides new targets for therapy

Intra‐clinothem variability in sedimentary texture and process regime recorded down slope profiles

Shelf‐margin clinothem successions can archive process interactions at the shelf to slope transition, and their architecture provides constraints on the interplay of factors that control basin‐margin evolution. However, detailed textural analysis and facies distributions from shelf to slope transitions remain poorly documented. This study uses quantitative grain‐size and sorting data from coeval shelf and slope deposits of a single clinothem that crops out along a 5 km long, dip‐parallel transect of the Eocene Sobrarbe Deltaic Complex (Ainsa Basin, south‐central Pyrenees, Spain). Systematic sampling of sandstone beds tied to measured sections has captured vertical and basinward changes in sedimentary texture and facies distributions at an intra‐clinothem scale. Two types of hyperpycnal flow‐related slope deposits, both rich in mica and terrestrial organic matter, are differentiated according to grain size, sorting and bed geometry: (i) sustained hyperpycnal flow deposits, which are physically linked to coarse channelized sediments in the shelf setting and which deposit sand down the complete slope profile; (ii) episodic hyperpycnal flow deposits, which are disconnected from, and incise into, shelf sands and which are associated with sediment bypass of the proximal slope and coarse‐grained sand deposition on the medial and distal slope. Both types of hyperpycnites are interbedded with relatively homogenous, organic‐free and mica‐free, well‐sorted, very fine‐grained sandstones, which are interpreted to be remobilized from wave‐dominated shelf environments; these wave‐dominated deposits are found only on the proximal and medial slope. Coarse‐grained sediment bypass into the deeper‐water slope settings is therefore dominated by episodic hyperpycnal flows, whilst sustained hyperpycnal flows and turbidity currents remobilizing wave‐dominated shelf deposits are responsible for the full range of grain sizes in the proximal and medial slope, thus facilitating clinoform progradation. This novel dataset highlights previously undocumented intra‐clinothem variability related to updip changes in the shelf process‐regime, which is therefore a key factor controlling downdip architecture and resulting sedimentary texture

Cleavage of the urokinase receptor (uPAR) on oral cancer cells : regulation by transforming growth factor - beta 1 (TGF-beta 1) and potential effects on migration and invasion

Background: Urokinase plasminogen activator (uPA) receptor (uPAR) is up-regulated at the invasive tumour front of human oral squamous cell carcinoma (OSCC), indicating a role for uPAR in tumour progression. We previously observed elevated expression of uPAR at the tumour-stroma interface in a mouse model for OSCC, which was associated with increased proteolytic activity. The tumour microenvironment regulated uPAR expression, as well as its glycosylation and cleavage. Both full-length- and cleaved uPAR (uPAR (II-III)) are involved in highly regulated processes such as cell signalling, proliferation, migration, stem cell mobilization and invasion. The aim of the current study was to analyse tumour associated factors and their effect on uPAR cleavage, and the potential implications for cell proliferation, migration and invasion. Methods: Mouse uPAR was stably overexpressed in the mouse OSCC cell line AT84. The ratio of full-length versus cleaved uPAR as analysed by Western blotting and its regulation was assessed by addition of different protease inhibitors and transforming growth factor - beta 1 (TGF-beta 1). The role of uPAR cleavage in cell proliferation and migration was analysed using real- time cell analysis and invasion was assessed using the myoma invasion model. Results: We found that when uPAR was overexpressed a proportion of the receptor was cleaved, thus the cells presented both full-length uPAR and uPAR (II-III). Cleavage was mainly performed by serine proteases and urokinase plasminogen activator (uPA) in particular. When the OSCC cells were stimulated with TGF-beta 1, the production of the uPA inhibitor PAI-1 was increased, resulting in a reduction of uPAR cleavage. By inhibiting cleavage of uPAR, cell migration was reduced, and by inhibiting uPA activity, invasion was reduced. We could also show that medium containing soluble uPAR (suPAR), and cleaved soluble uPAR (suPAR (II-III)), induced migration in OSCC cells with low endogenous levels of uPAR. Conclusions: These results show that soluble factors in the tumour microenvironment, such as TGF-beta 1, PAI-1 and uPA, can influence the ratio of full length and uPAR (II-III) and thereby potentially effect cell migration and invasion. Resolving how uPAR cleavage is controlled is therefore vital for understanding how OSCC progresses and potentially provides new targets for therapy.Peer reviewe

A database solution for the quantitative characterisation and comparison of deep-marine siliciclastic depositional systems

In sedimentological investigations, the ability to conduct comparative analyses between deep-marine depositional systems is hindered by the wide variety in methods of data collection, scales of observation, resolution, classification approaches and terminology. A relational database, the Deep-Marine Architecture Knowledge Store (DMAKS), has been developed to facilitate such analyses, through the integration of deep-marine sedimentological data collated to a common standard. DMAKS hosts data on siliciclastic deep-marine system boundary conditions, and on architectural and facies properties, including spatial, temporal and hierarchical relationships between units at multiple scales. DMAKS has been devised to include original and literature-derived data from studies of the modern sea-floor, and from ancient successions studied in the sub-surface and in outcrop. The database can be used as a research tool in both pure and applied science, allowing the quantitative characterisation of deep-marine systems. The ability to synthesise data from several case studies and to filter outputs on multiple parameters that describe the depositional systems and their controlling factors enables evaluation of the degree to which certain controls affect sedimentary architectures, thereby testing the validity of existing models. In applied contexts, DMAKS aids the selection and application of geological analogues to hydrocarbon reservoirs, and permits the development of predictive models of reservoir characteristics that account for geological uncertainty. To demonstrate the breadth of research applications, example outputs are presented on: (i) the characterisation of channel geometries, (ii) the hierarchical organisation of channelised and terminal deposits, (iii) temporal trends in the deposition of terminal lobes, (iv) scaling relationships between adjacent channel and levee architectural elements, (v) quantification of the likely occurrence of elements of different types as a function of the lateral distance away from an element of known type, (vi) proportions and transition statistics of facies in elements and beds, (vii) variability in net-to-gross ratios among element types

Numerical modelling and photo-electrochemical characterization of dye sensitized solar cells

Current-potential characteristics were recorded, and intensity modulated photocurrent spectroscopy (IMPS), intensity modulated photovoltage spectroscopy (IMVS), and electrochemical impedance spectroscopy (EIS) was performed on two DSSC s. The two DSSC s were made identical, except that one was made with a well-known ruthenium dye (N719), and the other one with a novel ruthenium-free purely organic dye (AFB5-098, abbreviated AFB8). Anta et al. s numerical version of the diffusion model[1] was extended to include small amplitude perturbation and used to interpret the experimental data. This made a basis from which the solar cells could be characterized and compared, and suggestions for ways to improve the cells were presented. The extended numerical model reproduced both the experimental IV-characteristic and the IMPS and IMVS spectra with good, if not perfect, accuracy. It was further revealed by the model that the N719- DSSC had poor charge capture efficiency, but excellent injection and absorption efficiency. The AFB8-DSSC on the other hand, had excellent charge collection efficiency, but seemed to have sub-optimal injection and/or absorbance efficiency. There were strong indications that the N719-DSSC could benefit significantly from decreased thickness of the titanium dioxide layer and quicker diffusion. There were some indications that the AFB8- DSSC could increase its efficiency moderately from a thicker titanium dioxide layer. Both cells would gain a higher potential from slower recombination, while the N719-DSSC would also gain increased current density from it. All in all, the combination of the numerical modelling and the photo-electrochemical experimental work was successful at both characterizing and suggesting ways to optimize the solar cells

Role of leptin in reproductive function of male dog

Studies investigating leptins role in canine male reproductive function has not previously been done. For that particular reason, this evaluation of a previous pilot study was designed to investigate the presence of leptin and leptin receptors in canine testis, epididymis and spermatozoa. Obesity is currently the most frequent nutritional disease existing in companion animals, however this increasingly issue is not given proper attention. In obese animals an increased amount of adipose tissue is found. With an excess of adipocytes, an increased level of leptin will be produced. An interesting question is therefore raised, and it could possibly be of great value if we were capable of finding out whether leptin demonstrates an impact towards the male reproductive function. However, this issue should be investigated by first examining the role of leptin in the function of the male genital tract of healthy dogs in normal condition. In this research we obtained samples from six healthy and mature dogs. The samples were collected through routinely neutering and manual semen collection. In this thesis, we performed the analysis of results from a previously performed sample collection and immunohistochemical examination. I compared these results to the data in literature in other species. Testis and epididymis were fixed in formalin and finally embedded in paraffin prior to immunohistochemistry identification. We used an indirect immunoperoxidase method to perform the immunohistochemistry. Rabbit polyclonal antibodies were used for detection of leptin and goat polyclonal antibodies for leptin receptors. Murine ovaries with CL and canine CL were used as positive controls, and a chromogenic agent was applied to make it possible to evaluate the result. The slides were assessed under 100x magnification. A full sperm-rich portion of semen was collected by manual stimulation. Both epididymal and ejaculated spermatozoa were further purified using the swim-up technique prior to immunocytochemistry identification. The samples were collected, purified and processed and 4 the immunocytochemical expression of the antibodies was obtained through the same indirect immunoperoxidase method as used in immunohistochemistry. The Objective of this study is to investigate if it is possible to detect leptin and its receptors in the male reproductive tract of canines with the use of immunohistochemistry and immunocytochemistry