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This study was undertaken to elucidate the molecular mechanisms by which lithium regulates the development of spinal cord-derived neural progenitor cells (NPCs) in vitro and after transplanted in vivo. Our results show that lithium at the therapeutic concentration significantly increases the proliferation and neuronal differentiation of NPCs in vitro. Specific ELISAs, western blotting, and quantitative real-time RT-PCR assays demonstrate that lithium treatment significantly elevates the expression and production of brain-derived neurotrophic factor (BDNF) by NPCs in culture. Application of a BDNF neutralizing antibody in culture leads to a marked reduction in the neurogenesis of lithium-treated NPCs to the control level. However, it shows no effects on the proliferation of lithium-treated NPCs. These findings suggest that the BDNF pathway is possibly involved in the supportive role of lithium in inducing NPC neurogenesis but not proliferation. This study also provides evidence that lithium is able to elevate the neuronal generation and BDNF production of NPCs after transplantation into the adult rat ventral horn with motoneuron degeneration because of spinal root avulsion, which highlights the therapeutic potential of lithium in cell replacement strategies for spinal cord injury because of its ability to promote neuronal differentiation and BDNF production of grafted NPCs in the injured spinal cord. [ABSTRACT FROM AUTHOR]

AbstractIn the present study, we transplanted E13.5 spinal cord–derived neural progenitor cells (NPCs) into the acutely avulsed ventral horn of adult rats. The results showed that NPCs survived and integrated nicely within the host ventral horn at 6 weeks post-grafting. Although the majority of grafted NPCs differentiated into astrocytes and only a small proportion into neuronal cells, interestingly, grafted NPCs in the avulsed ventral horn significantly enhanced the survival of injured motoneurons and promoted their regeneration into a peripheral nerve (PN) graft, as revealed by retrograde FluoroGold (FG) labeling. Specific ELISAs, Western blotting, and quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR) demonstrated that NPCs produced nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and glial cell line–derived neutrophilic factor (GDNF), both in vitroand after transplantation in vivo. These results indicate that NPCs have beneficial effects on the survival and axonal regeneration of avulsion-injured motoneurons after transplantation. Such beneficial effects are possibly due to their inherent ability to secrete various trophic factors after transplantation in vivo. [ABSTRACT FROM AUTHOR]

Dynamic modeling and vibration characteristics of a rotating sandwich beam filled with an electrorheological (ER) materials layer are investigated in this study. The stress-strain relationship for the ER fluids is described by a complex shear modulus using linear visco-elasticity theory. A dynamic equation of the rotating ER beam is derived based on Hamilton's principle. The coupling and nonlinear equation is discretized and solved by the finite element method (FEM). The influence of various electric field strengths and rotating speeds on the natural frequencies and damping loss factors of the rotating ER beam are presented. The amplitudes of vibration at different operation conditions are compared. The results obtained indicate that significant vibration attenuation is achieved as the electric field is increased at different rotating speeds, and demonstrate the feasibility of using the ER fluids to control the vibration of the rotating beam. [ABSTRACT FROM AUTHOR]

Demyelinating diseases, such as multiple sclerosis, are characterized by the loss of the myelin sheath around neurons, owing to inflammation and gliosis in the central nervous system (CNS). Current treatments therefore target anti-inflammatory mechanisms to impede or slow disease progression. The identification of a means to enhance axon myelination would present new therapeutic approaches to inhibit and possibly reverse disease progression. Previously, LRR and Ig domain–containing, Nogo receptor–interacting protein (LINGO-1) has been identified as an in vitro and in vivo negative regulator of oligodendrocyte differentiation and myelination. Here we show that loss of LINGO-1 function by Lingo1 gene knockout or by treatment with an antibody antagonist of LINGO-1 function leads to functional recovery from experimental autoimmune encephalomyelitis. This is reflected biologically by improved axonal integrity, as confirmed by magnetic resonance diffusion tensor imaging, and by newly formed myelin sheaths, as determined by electron microscopy. Antagonism of LINGO-1 or its pathway is therefore a promising approach for the treatment of demyelinating diseases of the CNS. [ABSTRACT FROM AUTHOR]

This paper proposes a dynamical model and the governing equations of motion of the micro-cantilever beams based MEMS with piezoelectric actuator (PZT). The Rayleigh–Ritz method is used to reduce the order of the system and the state equations are presented in modal space. The first ten mode frequencies and mode shapes of the micro-cantilever beam with and without PZT are studied. The effects of PZT on the modal frequencies and shapes of the beam system can be ignored for the reason that the beam holds larger nature frequencies and Q values in micro-scale. A rational linearizing feedback controller with a high gain observer is designed to eliminate the unwanted deflection of the micro-cantilever beam system. The open-loop step response and the effects of situated places of PZT on the frequency responses of the system are discussed. Various frequency responses of the beam system, subject to different applied control voltages and feedback gains, are illustrated. The four resonances are well controlled, while the anti-resonance has little change. Computer simulations are provided to demonstrate the performance of the designed control scheme. [ABSTRACT FROM AUTHOR]

A novel three-dimensional (3D) bifunctional electrocatalyst, CoNi alloy nanoparticle and carbon nanotube decorated N-doped carbon nanosheet arrays on carbon cloth (CoNi alloy/NCNSAs/CC) derived from polymetallic organic frameworks, is firstly prepared. The CoNi alloy/NCNSAs/CC-800 fabricated by pyrolyzing at 800 °C exhibits an oxygen reduction reaction (ORR, limiting current density) of 6.5 mA cm−2 and a superior oxygen evolution reaction (OER, at 10 mA cm−2) of 1.51 V, as well as a smaller potential difference of 0.676 V between OER and ORR half-wave potential, outperforming previous self-supporting cathodes. Flexible Zn-air batteries (FZABs) assembled with the CoNi alloy/NCNSAs/CC-800 exhibit higher energy density (98.8 mW cm−2) and higher capacity (879 mAh g−1), as well as excellent mechanical cycle ability (lower voltage gap of 0.66 V during the charge/discharge cycles at flat and folded state), significantly outstripping all other FZABs with self-supporting electrodes currently reported. Such a remarkable performance is ascribed to the 3D hierarchical nanostructure which promotes mass transport, the higher graphitization facilitating electronic mobility and the evenly dispersed active sites which accelerate kinetic reactions. So CoNi alloy/NCNSAs/CC-800 is a promising cathode candidate for ideal wearable energy devices and has great potential application in the field of electrochemical energy storage and conversion. [ABSTRACT FROM AUTHOR]

The displacement measurement with frequency-modulated continuous-wave radar based on radar interferometry technique has attracted growing interest in recent years. One of the main challenging issues is the static clutter interference in the same range bin, which results in amplitude shrinkage. A novel approach from signal processing side is proposed, i.e. implementing a post-processing procedure based on phasor offset compensation, which can be formulated as a circle fitting problem regarding phasor representation. Both simulated and experimental results are provided to validate the effectiveness and superiority of the proposed technique. [ABSTRACT FROM AUTHOR]

In this paper, aiming to achieve high-resolution frequency estimation for frequency-modulated continuous wave (FMCW) radar applications, a novel frequency estimation algorithm based on parameterized de-alternating (PDA) is proposed. According to the beat signal model, the proposed PDA method is performed with a matched kernel function to achieve the best de-alternating performance (i.e. the maximum conversion from an oscillating signal to a constant signal). The kernel parameter is estimated by solving an optimization problem which is simple and computationally efficient. Moreover, for a multiple target scenario, the intrinsic chirp component decomposition (ICCD) method is employed to isolate different components of the beat signal, which can eliminate the mutual interference between adjacent components when performing the PDA method. Compared with the commonly used FFT technique, our method can greatly improve the frequency estimation resolution and achieve superior ranging performance with a limited bandwidth. Both simulated and experimental validations are provided to show the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

Artificial multi-enzyme cascades bear great potential for bioconversion of C1 compounds to value-added chemicals. Over the past decade, massive efforts have been devoted to constructing multi-enzyme cascades to produce glycolic acid, rare functional sugars and even starch from C1 compounds. However, in contrast to traditional fermentation utilizing C1 compounds with the expectation of competitive economic performance in future industrialization, multi-enzyme cascades systems in the proof-of-concept phase are facing the challenges of upscaling. Here, we offered an overview of the recent advances in the construction of in vitro multienzyme cascades and whole-cell transformation using C1 compounds as substrate. In addition, the existing challenges and possible solutions were also discussed aiming to combine the strengths of in vitro and in vivo multi-enzyme cascades systems for upscaling. [ABSTRACT FROM AUTHOR]

Flexible pressure sensors have received significant attention for applications in wearable devices and human health monitoring in healthcare. Nevertheless, the preparation of pressure sensors with a wide operating range and high sensitivity remains a huge challenge. Herein, a piezoresistive sensor with a porous microstructure is prepared by using a sandpaper and salt dual-template method. Carbon black and carbon nanotubes are used as conductive fillers and the pressure sensor shows a high sensitivity (58.33 kPa-1) and extremely fast response and recovery times (3 and 10 ms, respectively). Furthermore, this CNT/PDMS/CB sensor shows a high detection limit of 400 kPa and excellent cycling stability of over 20 000 cycles. This high-performance pressure sensor is promising for many applications such as wearable electronics and health monitoring. [ABSTRACT FROM AUTHOR]

Consolidated bioprocessing (CBP) is a promising approach to directly convert lignocellulose feedstocks into targeted biochemicals and biofuels, and is commonly executed by single engineered microorganisms. Alternatively, the complex metabolic functions can be compartmentalized into different specialized microorganisms by using microbial consortia. In this study, a simplified microbial consortium was reassembled consisting of the lignocellulose degrader Trichoderma asperellum and lactic acid (LA) producer Lactobacillus paracasei, which were derived from the same native microbial consortium. The novel strategy of "learning from nature" combined with "simplifying the native microbial consortium" successfully increased cellulosic LA production from 7.36 g L-1 (native microbial consortium) to 57.57 g L-1 owing to the members' co-operation. Especially, over 80% carbon flux flowed from Avicel into LA synthesis with a yield of 0.92 g g-1. Furthermore, these two members can co-exist after compartmentalization into different spatial structures based on an aggregated granule of hydrogel-embedded L. paracasei and the formed biofilm of T. asperellum, leading to a 29.41% increase of LA productivity. This successfully constructed microbial consortium creates individual ecological niches to meet different oxygen demands, which enables more efficient co-operative performance in LA production from lignocellulose biomass. The analysis of interactions between these two members also provides insights on synthetic microbial consortium construction for the synthesis of other chemicals. [ABSTRACT FROM AUTHOR]

Treatment of malodor in the sewer system is a priority in many municipalities for human health concerns, sewer pipe corrosion prevention. In this study, the removal effects of iron-carbon (Fe–C) particles on the inhibition of sulfide in the liquid phase, as well as hydrogen sulfide (H 2 S) and methyl mercaptan (MeSH) in the headspace were investigated using laboratory-scale reactors simulating gravity-flow sewer system. The results indicated that the sulfide in the liquid phase can be reduced from 15.1 to 16.5 mg S/L to 0.05 and 0.14 mg S/L after 70 g/L and 50 g/L Fe–C particles dosing. The flux of H 2 S and MeSH in the headspace was also inhibited, and its flux decreased by up to 99%. Meanwhile, the microbial community structures of sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) in the sediment surface and water were also analyzed, and the results revealed that the relative abundance of SRB in the water and sediment surface was inhibited greatly after adding Fe–C particles, especially for Sulfurospirillum , Clostridium , and Desulfovibrio , while Fe–C particles promoted the growth of SOB. Moreover, the surface deposition was collected and analyzed through X-ray photoelectron spectroscopy (XPS), and the results indicated that sulfide can be removed by co-precipitation with ferrous ions formed through micro-electrolysis of Fe–C. This study provides a new approach to control the in-situ odor pollution for sewage systems. • Above 50 g/L Fe–C particles dosing can removal up to 99% sulfide. • H 2 S and MeSH flux decreased by above 99% after Fe–C particles dosing. • Fe–C particles dosing inhibited sulfate-reducing bacteria and promoted sulfur-oxidizing bacteria in water and sediment surface. • HS− was alleviated through precipitation as FeS and oxidation partially into Sulfur. [ABSTRACT FROM AUTHOR]

The article reports the wave-confining metasphere beamforming acoustic sensor (MBAS) for superior human-machine voice interaction. It shows the MBAS-based auditory system, high-performance audio cloning, source localization, and speech recognition in a noisy environment without any signal enhancement, revealing its applications in various voice interaction systems.

The elongation growth of the mushroom stipe is a characteristic but not well-understood morphogenetic event of Basidiomycetes. We found that extending native stipe cell walls of Coprinopsis cinerea were associated with the release of N-acetylglucosamine and chitinbiose and with chitinase activity. Two chitinases, ChiE1 and ChiIII, among all detected chitinases from C. cinerea reconstituted heat-inactivated stipe wall extension and released N-acetylglucosamine and chitinbiose. Interestingly, both ChiE1 and ChiIII hydrolyze insoluble crystalline chitin powder while other C. cinerea chitinases do not, suggesting that crystalline chitin components of the stipe cell wall are the target of action for ChiE1 and ChiIII. ChiE1- or ChiIII-reconstituted heat-inactivated stipe walls showed maximal extension activity at pH 4.5, consistent with the optimal pH for native stipe wall extension in vitro; ChiE1- or ChiIII-reconstituted heat-inactivated stipe wall extension activities were associated with stipe elongation growth regions; combination of ChiE1 and ChiIII showed a synergism to reconstitute heat-inactivated stipe wall extension at a low action concentration. Field emission scanning electron microscopy images explored that the inner surface of acid-induced extended native stipe cell walls and ChiE1- or ChiIII-reconstituted extended heat-inactivated stipe cell walls exhibited a partially broken parallel microfibril architecture, however, this broken transversely arranged microfibrils were not observed in the unextended stipe cell walls that were induced by neutral pH buffer or heat-inactivated. Double knockdown of ChiE1 and ChiIII resulted in the reduction of stipe elongation, mycelium growth, and heat-sensitive cell wall extension of native stipes. Above results indicate a chitinase-hydrolyzing mechanism for stipe cell wall extension. Importance A remarkable feature in the development of basidiomycete fruiting bodies is stipe elongation growth that results primarily from manifold cell elongation. Some scientists have suggested that stipe elongation is the result of enzymatic hydrolysis of cell wall polysaccharides, while other scientists have proposed that stipe elongation results from the nonhydrolytic disruption of the hydrogen bonds between cell wall polysaccharides. Here, we show direct evidences for a chitinase-hydrolyzing mechanism of stipe cell wall elongation in the model mushroom C. cinerea which is different from the expansin non-hydrolysis mechanism of plant cell wall extension. We presumed that in the growing stipe cell walls, parallel chitin microfibrils are tethered by β-1,6-branched β-1,3-glucans and that the breaking of the tether by chitinases leads to separation of these microfibrils to increase their spacing for insertion of new synthesized chitin and β-1,3-glucans under turgor pressure in vivo. [ABSTRACT FROM AUTHOR]

In this work, the nonlinear dynamic characteristics of a large-scale tilting pad journal bearings-rotor system with oil-film force model are investigated. The oil-film force of the 4-tilting-pad journal bearings considering oil cavitation is studied, and it is indicated that preload coefficient, wrapping and swing angle of pad have effects on the force. The system state trajectory, Poincaré maps, frequency spectra and bifurcation diagram are constructed to analyse the nonlinear dynamic characteristics of the double cantilever rotor supported by the tilting pad journal bearings in a large-scale turbo expander. The result from the numerical analysis is in agreement with behaviors of the turbo expander, and it is shown that the tilting pad journal bearings are more stable because of better oil-film distribution and larger oil-film force than that of the conventional plain bearing. Oil whirl and oil whip have an important influence on vibration of the rotor system. The study makes sense to improvement of the turbo expander and may contribute to a further understanding of its nonlinear dynamics. [ABSTRACT FROM AUTHOR]

This paper concerns the characteristics of a novel quasi-zero stiffness (QZS) isolator developed by parallelly combining a slotted conical disk spring with a vertical linear spring. The static characteristics of the slotted conical disk spring as well as the QZS isolator are presented. The configurative parameters are optimized to achieve a wide displacement range around the equilibrium position for which the stiffness has a low value and changes slightly. The overload and underload conditions are taken into account, resulting in a Helmoholtz-Duffing equation. The primary resonance response of the nonlinear system composed by a loaded mass and the QZS isolator are determined by employing the Harmonic Balance Method (HBM) and confirmed with the results of numerical simulation. The frequency response curves (FRCs) are obtained for both force and displacement excitations. The force transmissibility, the absolute displacement and acceleration transmissibility are defined and investigated. The study shows that the overloaded or underloaded system can exhibit linear stiffness, softening stiffness, softening-hardening stiffness and hardening stiffness with the increasing excitation amplitude. The response and the resonance frequency of the system are affected by the excitation amplitude and the offset displacement to the position at which the dynamic stiffness is zero. To enlarge the isolation frequency range and improve the isolation performance, the loaded mass and the excitation amplitude should be suitably controlled. [ABSTRACT FROM AUTHOR]