Simultaneous control of natural and extra degrees of freedom by isometric force and electromyographic activity in the muscle-to-force null space

Objective. Muscle activation patterns in the muscle-to-force null space, i.e., patterns that do not generate task-relevant forces, may provide an opportunity for motor augmentation by allowing to control additional end-effectors simultaneously to natural limbs. Here we tested the feasibility of muscular null space control for augmentation by assessing simultaneous control of natural and extra degrees of freedom. Approach. We instructed eight participants to control translation and rotation of a virtual 3D end-effector by simultaneous generation of isometric force at the hand and null space activity extracted in real-time from the electromyographic signals recorded from 15 shoulder and arm muscles. First, we identified the null space components that each participant could control more naturally by voluntary co-contraction. Then, participants performed several blocks of a reaching and holding task. They displaced an ellipsoidal cursor to reach one of nine targets by generating force, and simultaneously rotated the cursor to match the target orientation by activating null space components. We developed an information-theoretic metric, an index of difficulty defined as the sum of a spatial and a temporal term, to assess individual null space control ability for both reaching and holding. Main Results. On average, participants could reach the targets in most trials already in the first block (72%) and they improved with practice (maximum 93%) but holding performance remained lower (maximum 43%). As there was a high inter-individual variability in performance, we performed a simulation with different spatial and temporal task conditions to estimate those for which each individual participants would have performed best. Significance. Muscular null space control is feasible and may be used to control additional virtual or robotics end-effectors. However, decoding of motor commands must be optimized according to individual null space control ability.

Compact And Scalable Large Vortex Array Generation Using Azocarbazole Polymer And Digital Hologram Printing Technique

An integrated device capable of generating large number of multiplexed optical vortex beams with arbitrary topological charges is considered as one of the crucial requirement for driving information photonics forward. Here we report a simple method for simultaneous generation of 100 multiplexed optical vortex beams from a polymer film of size 1mm2 and thickness of 30µm. This is achieved through a combination of computer generated holography, digital hologram printing and photoisomeric polymers. When the fabricated sample is illuminated with a collimated laser beam, a predetermined vortex array with arbitrary topological charge is emitted. The polymer film easy to synthesise and exhibits good diffraction efficiency and long retention time.

Phonon-assisted electronic states modulation of few-layer PdSe2 at terahertz frequencies

Information technology demands high-speed optoelectronic devices, but going beyond the one terahertz (THz) barrier is challenging due to the difficulties associated with generating, detecting, and processing high-frequency signals. Here, we show that femtosecond-laser-driven phonons can be utilized to coherently manipulate the excitonic properties of semiconductors at THz frequencies. The precise control of the pump and subsequent time-delayed broadband probe pulses enables the simultaneous generation and detection processes of both periodic lattice vibrations and their couplings with electronic states. Combining ultralow frequency Raman spectroscopy with first-principles calculations, we identify the unique phonon mode-selective and probe-energy dependent features of electron–phonon interactions in layered PdSe2. Two distinctive types of coherent phonon excitations could couple preferentially to different types of electronic excitations: the intralayer (4.3 THz) mode to carriers and the interlayer (0.35 THz) mode to excitons. This work provides new insights to understand the excited-state phonon interactions of 2D materials and to achieve future applications of optoelectronic devices operating at THz frequencies.

Performance analysis of a novel cascade vapor compression system for small-scale desalination and cooling

The demand for improving living standards has led to increasing freshwater consumption and comfort cooling, requiring significant performance improvements. In this regard, a novel and efficient cascade refrigeration system for simultaneous generation of considerable freshwater and cooling amounts is proposed. The system does not require dedicated components for desalinating seawater because they are dual-purpose. Utilizing the cascade configuration enhances energy efficiency by lowering the compression work while improving energy recovery by utilizing existing heat to vaporize seawater for desalination. A mathematical model of the innovative system based on thermodynamic and economic principles has been developed and utilized to predict the proposed system's thermal performance and cost savings. A comprehensive analysis has been conducted to study the effect of multiple parameters such as the evaporator, condenser, and brine boiling temperatures. The main studied parameters were COP, GOR, freshwater production, and total cost savings. For a 10 TR unit, the freshwater production was between 56.11 – 73.36 kg/h, with cost savings reaching 2,226 US$/yr. It was found that the freshwater production increased with condenser and brine boiling temperature but decreased with evaporator temperature. The COP improvement can be as much as 26% over the reference cooling system without desalination.

Degradation of Micropollutants and Formation of Oxidation By-Products during the Ozone/Peroxymonosulfate System: A Critical Review

The O3/PMS system has appeared as an effective wastewater treatment method because of the simultaneous generation of hydroxyl radicals (•OH) and sulfate radicals (SO4•−). Many research achievements have been made on the degradation of micropollutants and the reaction mechanism of the O3/PMS system. However, an integral understanding of the O3/PMS system is lacking, which limits the development of safe and effective AOP-based water treatment schemes. Therefore, in this review, the degradation effects, toxicity changes, and reaction mechanisms of various micropollutants in the O3/PMS system are reviewed. The formation of oxidation by-products (OBPs) is an important issue that affects the practical application of O3/PMS systems. The formation mechanism and control methods of OBPs in the O3/PMS system are overviewed. In addition, the influence of different reaction conditions on the O3/PMS system are comprehensively evaluated. Finally, future research needs are proposed based on the limited understanding of O3/PMS systems in the degradation of micropollutants and formation of OBPs. Specifically, the formation rules of several kinds of OBPs during the O3/PMS system are not completely clear yet. Furthermore, pilot-scale research, the operational costs, sustainability, and general feasibility of the O3/PMS system also need to be studied. This review can offer a comprehensive assessment on the O3/PMS system to fill the knowledge gap and provide guidance for the future research and engineering applications of the O3/PMS system. Through this effort, the O3/PMS system can be better developed and turned towards practical applications.

Is low dose Tranexamic acid less effective than a standard dose at reducing blood loss and inhibiting hyperfibrinolysis in hemorrhagic caesarean section? Multicenter double–blind placebo-controlled dose-ranging (TRACES) trial.

Objective: To study the effect of a low (0.5g) or a standard (1g) tranexamic acid (TA) dose compared to placebo on clinical and biological endpoints in women experiencing postpartum hemorrhage (PPH) Design: TRACES trial is a double-blind, randomized, placebo-controlled, dose-ranging study Setting: 8 women hospitals in France. Population: Women experiencing PPH > 800 mL during caesarean section. Method: After informed consent, patients were randomized to receive either TA 0.5g (n=57), TA 1g (n=58), or a placebo (n=60). Data were collected at 8 time-points. Main outcome measures: Efficacy: additional blood loss after study drug, maternal morbidity, safety, biology: D-dimers, plasmin-antiplasmin complexes (PAP), simultaneous-generation-thrombin-plasmin-potential. Results: Compared to 1g dose, 0.5g TA was less effective to reduce additional blood loss (300 mL [95% confidence interval (95%CI) 68 to 630] vs 134 mL [95%CI50 to 419] (p=0.042)). Compared to placebo, 1g TA, but not 0.5g, inhibited hyperfibrinolysis as shown by plasmin generation potential, % increase in D-dimers from injection to 120 minutes (93% [95%CI 68 to 118] vs 58% [ 95%CI 32 to 84] (p=0.06) vs 38% [95%CI 13 to 63] (p=0.003) and % increase in PAP from injection to 30 minutes (56% [95%CI 25 to 87] vs 13% [ 95%CI 18 to 43] (p=0,051) vs -2% [95%CI -32 to 28] (p=0.009)). Conclusions: In this study, fibrinolysis inhibition was more sustained after the administration of 1g TA compared to 0.5g TA or a placebo. Further pharmacokinetic-pharmacodynamic modelling will be needed to determine the optimal TA dose to be administered in PPH. NCT 02797119

Electro-optic Q-switched Cr:LiSAF laser

We demonstrate electro-optic Q-switched solid state laser with Cr:LiSAF active medium. A single 50 ns pulse with 14 mJ of output energy is demonstrated. Simultaneous generation of several peaks with a step of 1.4 nm within the spectrum envelope with a full width at half maximum of 10.3 nm is demonstrated. For an electro-optic Q-switched mode a Pockels cell is used. Demonstrated laser can be used in differential absorption lidar systems.