Research on duplex underwater wireless laser communication system

To improve the bit error rate (BER) of underwater wireless laser communication and increase communication speed, a duplex underwater wireless laser communication system is designed. The system uses both blue and green lasers to transmit signals simultaneously, and adopts an improved modulation and demodulation algorithm to achieve separate modulation of the two sets of signals. A duplex underwater wireless laser communication system builds based on 440 and 550 nm lasers. On the basis of analyzing the absorption and scattering characteristics of seawater in laser communication, the influence of turbulence on communication efficiency is discussed. Improved the traditional duplex modulation algorithm and conducted communication testing at a depth of 2.0 m underwater. The experimental results show that when the communication distance increases from 5 to 50 m, the BER of the unoptimized duplex mode increases from 2.34 × 10−7 to 3.5 × 10−5. After adopting the optimization algorithm, the BER increases from 2.81 × 10−7 to 1.18 × 10−6, and the signal attenuation has been significantly suppressed. The duplex communication structure and algorithm can effectively reduce the impact of communication distance on bit BER

Transition from continental collision to tectonic escape? A geophysical perspective on lateral expansion of the northern Tibetan Plateau

A number of tectonic models have been proposed for the Tibetan Plateau, which origin, however, remains poorly understood. In this study, investigations of the shear wave velocity (Vs) and density (ρ) structures of the crust and upper mantle evidenced three remarkable features: (1) There are variations in Vs and ρ of the metasomatic mantle wedge in the hanging wall of the subduction beneath different tectonic blocks of Tibet, which may be inferred as related to the dehydration of the downgoing slab. (2) Sections depicting gravitational potential energy suggest that the subducted lithosphere is less dense than the ambient rocks, and thus, being buoyant, it cannot be driven by gravitational slab pull. The subduction process can be inferred by the faster SW-ward motion of Eurasia relative to India as indicated by the plate motions relative to the mantle. An opposite NE-ward mantle flow can be inferred beneath the Himalaya system, deviating E and SE-ward toward China along the tectonic equator. (3) The variation in the thickness of the metasomatic mantle wedge suggests that the leading edge of the subducting Indian slab reaches the Bangoin-Nujiang suture (BNS), and the metasomatic mantle wedge overlaps with a region with poor Sn-wave propagation in north Tibet. The metasomatic layer, north of the BNS, deforms in the E-W direction to accommodate lithosphere shortening in south Tibet

Excitatory microcircuits within superficial layers of the medial entorhinal cortex

The distinctive firing pattern of grid cells in the medial entorhinal cortex (MEC) supports its role in the representation of space. It is widely believed that the hexagonal firing field of grid cells emerges from neural dynamics that depends on the local microcircuitry. However, local networks within the MEC are still not sufficiently characterized. Here, applying up to eight simultaneous whole-cell recordings in acute brain slices, we demonstrate the existence of unitary excitatory connections between principal neurons in the superficial layers of the MEC. In particular, we find prevalent feed-forward excitation from pyramidal neurons in layer III and layer II onto stellate cells in layer II, which might contribute to the generation or the inheritance of grid-cell patterns

Dataset for: Modeling chemotherapy induced neurotoxicity with human induced pluripotent stem cell (iPSC)-derived sensory neurons

Chemotherapy-induced peripheral neuropathy (CIPN) is a frequent and potentially irreversible adverse event of cytotoxic chemotherapy. We evaluate whether sensory neurons derived from induced pluripotent stem cells (iPSC-DSN) can serve as human disease model system for chemotherapy induced neurotoxicity. Sensory neurons differentiated from two established induced pluripotent stem cell lines were used (s.c. BIHi005-A https://hpscreg.eu/cell- line/BIHi005-A and BIHi004-B https://hpscreg.eu/cell-line/BIHi004-B, Berlin Institute of Health Stem Cell Core Facility). Cell viability and cytotoxicity assays were performed, comparing susceptibility to four neurotoxic and two non-neurotoxic drugs. RNA sequencing analyses in paclitaxel vs. vehicle (DMSO)treated sensory neurons were performed. Treatment of iPSC-DSN for 24 h with the neurotoxic drugs paclitaxel, bortezomib, vincristine and cisplatin led to a dose dependent decline of cell viability in clinically relevant IC50 ranges, which was not the case for the non-neurotoxic compounds doxorubicin and 5-fluorouracil. RNA sequencing analyses at 24 h, i.e. before paclitaxel-induced cell death occurred, revealed the differential expression of genes of neuronal injury, cellular stress response, and sterol pathways in response to 1 mu M paclitaxel. Neuroprotective effects of lithium chloride co-incubation, which were previously shown in rodent dorsal root ganglia, could be replicated in human iPSC-DSN. Cell lines from the two different donors BIHi005-A and BIHi004-B showed different responses to the neurotoxic treatment in cell viability and cytotoxicity assays

Layer-specific organization of local excitatory and inhibitory synaptic connectivity in the rat presubiculum

Das Präsubiculum ist Teil des parahippocampalen Systems für die räumliche Navigation und beinhaltet als vorgeschaltete Region zum medialen entorhinalen Cortex sowohl "head direction" als auch "grid" Zellen. Aufgrund dieser Position innerhalb des parahippocampalen Cortex ist das Präsubiculum besonders geeignet um die Netzwerkstruktur zu untersuchen, die nötig für räumlich- kodierte Aktivität ist. Wir haben die synaptische Konnektivität zwischen Pyramidenzellen und Interneuronen in allen Schichten des Präsubiculums untersucht. Mit Einzelzellableitungen von bis zu acht Zellen gleichzeitig nach dem patch-clamp Verfahren haben wir 4250 potentielle synaptische Verbindungen getestet. Die Netzwerktopologie zeigte schichtspezifische Unterschiede, vereinbar mit der bekannten Unterscheidung in oberflächige und tiefe Schichten. Verbindungen zwischen Pyramidenzellen in den oberflächigen Schichten waren kaum vorhanden, während die tiefen Schichten eine exzitatorische Konnektivität von 3.9% aufwiesen. Im Gegensatz dazu war die synaptische Konnektivität bezüglich der Inhibition in den oberflächigen Schichten höher, jedoch deutlich niedriger als in anderen kortikalen Regionen. Die exzitatorischen als auch inhibitorischen postsynaptischen Amplituden zeigten eine log-normale Verteilung, die auf eine nicht zufällige funktionale Konnektivität hinweist. Unsere Studie hat neue region- und schichtspezifische Aspekte der lokalen Netzwerkarchitektur aufgedeckt, die als Randbedingungen für zukünftige Modelle zur räumlichen Navigation wichtig sind.The presubiculum is a brain region located between the hippocampus and the entorhinal cortex. It accommodates grid and head direction cells which are key components of the spatial navigation system. Being upstream to the medial entorhinal cortex, it is an ideal region to investigate the network properties required for the generation of spatially tuned activity. We analyzed the synaptic connectivity of interneurons and pyramidal cells throughout all layers using simultaneous whole-cell patch-clamp recordings of up to 8 cells. We tested 4250 potential synaptic connections and found layer-specific differences in network organization consistent with the established separation in superficial and deep layers. Superficial layers almost lacked any excitatory connectivity among pyramidal cells while deep layers showed a connectivity of 3.9%. On the contrary, inhibitory connectivity was higher in superficial layers, however clearly lower than in other brain regions. Additionally, postsynaptic amplitudes of excitatory and inhibitory connections exhibited log-normal distributions, indicating a non-random functional connectivity. Summing up, we have provided new insights into the network topology of the presubiculum by finding layer- and area-specific rules of connectivity. These organization principles are necessary to constrain future models of the spatial navigation system

Trans-Polyisoprene/Poly (Ethylene-co-Vinyl Acetate) Polymer Composites as High-Performance Triple Shape Memory Materials

The performance and programming conditions of the triple shape memory of crosslinked trans-polyisoprene/poly (ethylene-co-vinyl acetate) (TPI/EVA) composites with different contents of dicumyl peroxide (DCP) were investigated. The effect of triple shape memory in the TPI/EVA composites was studied by tensile loading, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and dynamic thermomechanical analysis (DMA). It was demonstrated that the content of DCP increased, the crystallization temperature of TPI decreased from 55.2 to 38.3 °C, and the crystallization temperature of EVA decreased slightly. The SEM results showed that DCP, as an initiator, could form a graft copolymer of TPI-g-EVA at the interface of the two phases, which could improve the adhesion of the two phases. The DMA showed that the higher the content of DCP, the higher the first-stage shape recovery ratio. Moreover, the composites exhibited favorable shape fixity ratio (Rf) and shape recovery ratio (Rr) with the incorporation of 0.4 phr DCP. At the same time, it was demonstrated that the TPI/EVA composites showed excellent mechanical strength, including tensile strength up to 24.3 MPa, as well as elongation at break reaching 508%

Building a Multi-FPGA-based Emulation Framework to Support networks-on-chip Design and Verification

In this article, we present a highly scalable, flexible hardware-based network-on-chip (NoC) emulation framework, through which NoCs built upon various types of network topologies, routing algorithms, switching protocols and flow control schemes can be explored, compared, and validated with injected or self-generated traffic from both real-life and synthetic applications. This high degree of scalability and flexibility is achieved due to the field programmable gate array (FPGA) design choices made at both functional and physical levels. At the functional level, a NoC system to be emulated can be partitioned into two parts: (i) the processing cores and (ii) the network. Each part is mapped onto a different FPGA so that when there is any change to be made to any one of these parts, only the corresponding FPGA needs to be reconfigured and the rest of the FPGAs will be left untouched. At the physical level, two levels of interconnects are adopted to mimic NoC on-chip communications: high bandwidth and low latency parallel on-board wires, and high-speed serial multigigabit transceivers available in FPGAs. The latter is particularly important as it helps the proposed NoC emulation platform scale well with the size increase of the NoCs

Magmatic underplating beneath the Emeishan large igneous province (South China) revealed by the COMGRA-ELIP experiment

Loyang [Luoyang] Lung Men [Longmen]ColorVolume 55, Page 1

Lithospheric structure in the Cathaysia block (South China) and its implication for the Late Mesozoic magmatism

Mesozoic granitoids are widely distributed in South China, but the mechanism for generating the felsic magmas is still in debate. To understand the possible origin of the granitoids, we use joint inversion methods and forward modelling of receiver functions to reveal the lithospheric structure in the Cathaysia block. The joint inversion of receiver functions and surface wave dispersion with P-velocity constraints is applied to a dense array in the Cathaysia block, and the specific crustal Vp/Vs ratios obtained from a generalized H-kappa stacking method are introduced to the traditional joint inversion for passive seismic stations. The detailed structures provide valuable knowledge of the geological processes: 1) The present-day lithosphere is 60-70 km thick, which has been thinned since the Late Mesozoic with reference to geochemical data; 2) there is a lack of high Vp and Vs in the lower crust in this region. The results may have limited resolution on the localized magmatic underplating, but they do not support the extensive magmatic underplating at the Late Mesozoic. Other factors could be the mechanism for the granitoid formation in this region