Thermal power transfer system using applied potential difference to sustain operating pressure difference

A thermal power transfer system using a phase change liquid gas fluid in a closed loop configuration has a heat exchanger member connected to a gas conduit for inputting thermal energy into the fluid. The pressure in the gas conduit is higher than a liquid conduit that is connected to a heat exchanger member for outputting thermal energy. A solid electrolyte member acts as a barrier between the gas conduit and the liquid conduit adjacent to a solid electrolyte member. The solid electrolyte member has the capacity of transmitting ions of a fluid through the electrolyte member. The ions can be recombined with electrons with the assistance of a porous electrode. An electrical field is applied across the solid electrolyte member to force the ions of the fluid from a lower pressure liquid conduit to the higher pressure gas conduit

IST Austria Thesis

The medial habenula (MHb) is an evolutionary conserved epithalamic structure important for the modulation of emotional memory. It is involved in regulation of anxiety, compulsive behavior, addiction (nicotinic and opioid), sexual and feeding behavior. MHb receives inputs from septal regions and projects exclusively to the interpeduncular nucleus (IPN). Distinct sub-regions of the septum project to different subnuclei of MHb: the bed nucleus of anterior commissure projects to dorsal MHb and the triangular septum projects to ventral MHb. Furthermore, the dorsal and ventral MHb project to the lateral and rostral/central IPN, respectively. Importantly, these projections have unique features of prominent co-release of different neurotransmitters and requirement of a peculiar type of calcium channel for release. In general, synaptic neurotransmission requires an activity-dependent influx of Ca2+ into the presynaptic terminal through voltage-gated calcium channels. The calcium channel family most commonly involved in neurotransmitter release comprises three members, P/Q-, N- and R-type with Cav2.1, Cav2.2 and Cav2.3 subunits, respectively. In contrast to most CNS synapses that mainly express Cav2.1 and/or Cav2.2, MHb terminals in the IPN exclusively express Cav2.3. In other parts of the brain, such as the hippocampus, Cav2.3 is mostly located to postsynaptic elements. This unusual presynaptic location of Cav2.3 in the MHb-IPN pathway implies unique mechanisms of glutamate release in this pathway. One potential example of such uniqueness is the facilitation of release by GABAB receptor (GBR) activation. Presynaptic GBRs usually inhibit the release of neurotransmitters by inhibiting presynaptic calcium channels. MHb shows the highest expression levels of GBR in the brain. GBRs comprise two subunits, GABAB1 (GB1) and GABAB2 (GB2), and are associated with auxiliary subunits, called potassium channel tetramerization domain containing proteins (KCTD) 8, 12, 12b and 16. Among these four subunits, KCTD12b is exclusively expressed in ventral MHb, and KCTD8 shows the strongest expression in the whole MHb among other brain regions, indicating that KCTD8 and KCTD12b may be involved in the unique mechanisms of neurotransmitter release mediated by Cav2.3 and regulated by GBRs in this pathway. In the present study, we first verified that neurotransmission in both dorsal and ventral MHb-IPN pathways is mainly mediated by Cav2.3 using a selective blocker of R-type channels, SNX-482. We next found that baclofen, a GBR agonist, has facilitatory effects on release from ventral MHb terminal in rostral IPN, whereas it has inhibitory effects on release from dorsal MHb terminals in lateral IPN, indicating that KCTD12b expressed exclusively in ventral MHb may have a role in the facilitatory effects of GBR activation. In a heterologous expression system using HEK cells, we found that KCTD8 and KCTD12b but not KCTD12 directly bind with Cav2.3. Pre-embedding immunogold electron microscopy data show that Cav2.3 and KCTD12b are distributed most densely in presynaptic active zone in IPN with KCTD12b being present only in rostral/central but not lateral IPN, whereas GABAB, KCTD8 and KCTD12 are distributed most densely in perisynaptic sites with KCTD12 present more frequently in postsynaptic elements and only in rostral/central IPN. In freeze-fracture replica labelling, Cav2.3, KCTD8 and KCTD12b are co-localized with each other in the same active zone indicating that they may form complexes regulating vesicle release in rostral IPN. On electrophysiological studies of wild type (WT) mice, we found that paired-pulse ratio in rostral IPN of KCTD12b knock-out (KO) mice is lower than those of WT and KCTD8 KO mice. Consistent with this finding, in mean variance analysis, release probability in rostral IPN of KCTD12b KO mice is higher than that of WT and KCTD8 KO mice. Although paired-pulse ratios are not different between WT and KCTD8 KO mice, the mean variance analysis revealed significantly lower release probability in rostral IPN of KCTD8 KO than WT mice. These results demonstrate bidirectional regulation of Cav2.3-mediated release by KCTD8 and KCTD12b without GBR activation in rostral IPN. Finally, we examined the baclofen effects in rostral IPN of KCTD8 and KCTD12b KO mice, and found the facilitation of release remained in both KO mice, indicating that the peculiar effects of the GBR activation in this pathway do not depend on the selective expression of these KCTD subunits in ventral MHb. However, we found that presynaptic potentiation of evoked EPSC amplitude by baclofen falls to baseline after washout faster in KCTD12b KO mice than WT, KCTD8 KO and KCTD8/12b double KO mice. This result indicates that KCTD12b is involved in sustained potentiation of vesicle release by GBR activation, whereas KCTD8 is involved in its termination in the absence of KCTD12b. Consistent with these functional findings, replica labelling revealed an increase in density of KCTD8, but not Cav2.3 or GBR at active zone in rostral IPN of KCTD12b KO mice compared with that of WT mice, suggesting that increased association of KCTD8 with Cav2.3 facilitates the release probability and termination of the GBR effect in the absence of KCTD12b. In summary, our study provided new insights into the physiological roles of presynaptic Cav2.3, GBRs and their auxiliary subunits KCTDs at an evolutionary conserved neuronal circuit. Future studies will be required to identify the exact molecular mechanism underlying the GBR-mediated presynaptic potentiation on ventral MHb terminals. It remains to be determined whether the prominent presence of presynaptic KCTDs at active zone could exert similar neuromodulatory functions in different pathways of the brain

Robust Thermal Control of Propulsion Lines for Space Missions

A document discusses an approach to insulating propulsion lines for spacecraft. In spacecraft that have propulsion lines that are located externally with open bus architecture, the lines are typically insulated by Multi Layer Insulation (MLI) blankets. MLI on propulsion lines tends to have large and somewhat random variances in its heat loss properties (effective emittance) from one location to the next, which makes it an un-robust approach to control propulsion line temperatures. The approach described here consists of a clamshell design in which the inner surface of the shell is coated with low-emissivity aluminized Kapton tape, and the outer surface is covered with black tape. This clamshell completely encloses the propulsion line. The line itself is covered with its heater, which in turn, is covered completely with black tape. This approach would be low in heater power needs because even though the outer surface of the prop line (and its heater) is covered with black tape as well as the outer surface of the clamshell, the inner surface of the clamshell is covered with low-emissivity aluminized Kapton tape. Hence, the heat loss from the line will be small and comparable to the MLI based one. In terms of contamination changing the radiative properties of surfaces, since the clamshell s inner surface is always protected during handling and is only installed after all the work on the prop line has been completed, the controlling surface, which is the clamshell s inner surface, is always in pristine condition. This proposed design allows for a much more deterministic and predictable design using a very simple and implementable approach for thermal control. It also uses low heater power and is robust to handling and contamination during and after implementation

Recent advances in the management of large and complex colonic polyps

The endoscopic management of large colonic polyps is a rapidly changing field. Rapid evolution in endoscopic techniques and skills has resulted in diminishing the role of surgery in the management of larger and complex polyps. This is resulting in organ preservation for many who otherwise would have undergone surgery. However, it also poses new challenges. This article reviews these new advances and the developments which are overcoming these difficulties

Advances in the endoscopic diagnosis and treatment of Barrett’s neoplasia

Barrett’s oesophagus is a well-recognised precursor of oesophageal adenocarcinoma. The incidence of oesophageal adenocarcinoma is continuing to rise in the Western world with dismal survival rates. In recent years, efforts have been made to diagnose Barrett’s earlier and improve surveillance techniques in order to pick up cancerous changes earlier. Recent advances in endoscopic therapy for early Barrett’s cancers have shifted the paradigm away from oesophagectomy and have yielded excellent results

Deep learning-assisted high-throughput analysis of freeze-fracture replica images applied to glutamate receptors and calcium channels at hippocampal synapses

The molecular anatomy of synapses defines their characteristics in transmission and plasticity. Precise measurements of the number and distribution of synaptic proteins are important for our understanding of synapse heterogeneity within and between brain regions. Freeze–fracture replica immunogold electron microscopy enables us to analyze them quantitatively on a two-dimensional membrane surface. Here, we introduce Darea software, which utilizes deep learning for analysis of replica images and demonstrate its usefulness for quick measurements of the pre- and postsynaptic areas, density and distribution of gold particles at synapses in a reproducible manner. We used Darea for comparing glutamate receptor and calcium channel distributions between hippocampal CA3-CA1 spine synapses on apical and basal dendrites, which differ in signaling pathways involved in synaptic plasticity. We found that apical synapses express a higher density of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors and a stronger increase of AMPA receptors with synaptic size, while basal synapses show a larger increase in N-methyl-D-aspartate (NMDA) receptors with size. Interestingly, AMPA and NMDA receptors are segregated within postsynaptic sites and negatively correlated in density among both apical and basal synapses. In the presynaptic sites, Cav2.1 voltage-gated calcium channels show similar densities in apical and basal synapses with distributions consistent with an exclusion zone model of calcium channel-release site topography