Enhanced axon outgrowth of spinal motor neurons in co-culturing with dorsal root ganglions antagonizes the growth inhibitory environment.

Introduction: Forming a bridge made of functional axons to span the lesion is essential to reconstruct the motor circuitry following spinal cord injury (SCI). Dorsal root ganglion (DRG) axons are robust in axon growth and have been proved to facilitate the growth of cortical neurons in a process of axon-facilitated axon regeneration. However, whether DRG transplantation affects the axon outgrowth of spinal motor neurons (SMNs) that play crucial roles in motor circuitry remains unclear. Methods: We investigated the axonal growth patterns of co-cultured DRGs and SMN aggregates (SMNAs) taking advantage of a well-designed 3D-printed in vitro system. Chondroitin sulphate proteoglycans (CSPG) induced inhibitory matrix was introduced to imitate the inhibitory environment following SCI. Axonal lengths of DRG, SMNA or DRG & SMNA cultured on the permissive or CSPG induced inhibitory matrix were measured and compared. Results: Our results indicated that under the guidance of full axonal connection generated from two opposing populations of DRGs, SMNA axons were growth-enhanced and elongated along the DRG axon bridge to distances that they could not otherwise reach. Quantitatively, the co-culture increased the SMNA axonal length by 32.1 %. Moreover, the CSPG matrix reduced the axonal length of DRGs and SMNAs by 46.2 % and 17.7 %, respectively. This inhibitory effect was antagonized by the co-culture of DRGs and SMNAs. Especially for SMNAs, they extended the axons across the CSPG-coating matrix, reached the lengths close to those of SMNAs cultured on the permissive matrix alone. Conclusions: This study deepens our understanding of axon-facilitated reconstruction of the motor circuitry. Moreover, the results support SCI treatment utilizing the enhanced outgrowth of axons to restore functional connectivity in SCI patients.

Along with cyclic electron flow and non-photochemical quenching, water-to-water cycle is involved uniquely in alleviating Zn stress-caused photodamage in Melia azedarach.

Zinc (Zn) is a widespread industrial pollutant that has detrimental effects on plant growth and development. Photoprotective properties ensure plant survival during stress by protecting the photosynthetic apparatus. This occurs via numerous mechanisms, including non-photochemical quenching (NPQ), cyclic electron flow (CEF) and the water-to-water cycle (WWC). However, whether and how Zn stress affects the photoprotective properties of plants to enhance the tolerance of Zn toxicity remains unknown. In this study, we treated Melia azedarach plants with different Zn concentrations ranging from 200 to 1000 mg kg-1. We then analyzed the activities of two leaf photosynthetic pigment components-photosystems I and II (PSI and PSII)-and the relative expression levels of their subunit genes. As expected, we found that Zn treatment decreases photosynthesis and increases photodamage in M. azedarach leaves. The Zn treatments exacerbated a variety of photodamage phenotypes in photosystem activities and altered the expression levels of key photosystem complex genes and proteins. Furthermore, our results demonstrated that PSI was more seriously damaged than PSII under Zn stress. Subsequently, we compared differences in photodamage in the NPQ, CEF and WWC photoprotection pathways under Zn stress and found that each exerted a protective function again photodamage under 200 mg kg-1 Zn stress. The NPQ and CEF may also play major protective roles in the avoidance of irreversible photodamage and helping to ensure survival under higher (i.e., 500 and 1000 mg kg-1) levels of Zn stress. Thus, our study revealed that NPQ- and CEF-based photoprotection mechanisms are more effective than WWC in M. azedarach upon Zn stress.

Soil microbial communities and their co-occurrence networks in response to long-term Pb-Zn contaminated soil in southern China.

Mining causes extreme heavy metal (HM) contamination to surrounding environments and poses threats to soil microbial community. The effects of HMs on soil microbial communities are not only related to their total amounts but also associated with the distribution of chemical fractions. However, the effects of chemical fractions on soil microbes and their interactions remain largely unclear. Here we investigated soil physicochemical properties and bacterial and fungal communities of soil samples from the control area and lightly (L), moderately (M), and heavily (H) contaminated areas, respectively, which were collected from long-term Pb-Zn slag contamination area in the southern China. The results showed that bacterial and fungal community composition and structure were significantly affected by HMs, while community diversity was not significantly affected by HMs. The critical environmental factor affecting bacterial and fungal communities was pH, and the impacts of chemical fractions on their changes were more significant than the total amounts of HMs. Variance partitioning analysis (VPA) revealed fungal community changes were mostly driven by HM total amounts, but bacterial community changes were mostly driven by soil chemical properties. Co-occurrence network indicated that interactions among species of fungal network were sparser than that of bacterial network, but fungal network was more stable, due to a more significant number of keystone taxa and a lower percentage of positive associations. These illustrated that the fungal community might serve as indicator taxa for HM-contaminated status, and specific HM-responsive fungal species such as Triangularia mangenotii, Saitozyma podzolica, and Cladosporium endophytica, and genus Rhizophagus can be considered relevant bioindicators due to their less relative abundance in contaminated areas. Additionally, HM-responsive bacterial OTUs representing five genera within Sulfurifustis, Thiobacillus, Sphingomonas, Qipengyuania, and Sulfurirhabdus were found to be tolerant to HM stress due to their high relative abundance in contaminated levels.

Study on Self-Humidification in PEMFC with Crossed Flow Channels and an Ultra-Thin Membrane.

In this study, a 3D model of a proton exchange membrane fuel cell (PEMFC) with crossed channels and an ultra-thin membrane is developed to investigate the feasibility of self-humidification; experiments utilizing a PEMFC stack with identical configurations are conducted to validate the simulation results and further investigate the effects of various operating conditions (OCs) on self-humidification. The results indicate that the crossed flow channel leads to enhanced uniformity of water distribution, resulting in improved cell performance under low/no humidification conditions. External humidifiers for the anode can be removed since the performance difference is negligible (≤3%) between RHa = 0% and 100%. Self-humidification can be achieved in the stack at 90 °C or below with an appropriate back pressure among 100-200 kPa. As the current density increases, there is a gradual convergence and crossing of the voltage at low RH with that at high RH, and the crossover points are observed at 60-80 °C with suitable pressure when successful self-humidification is achieved. Below the current density of the point, the stack's performance is inferior at lower RH due to membrane unsaturation, and conversely, the performance is inferior at higher RH due to flooding; this current density decreases with higher pressure and lower temperature.

Cascaded Attention: Adaptive and Gated Graph Attention Network for Multiagent Reinforcement Learning.

Modeling the interactive relationships of agents is critical to improving the collaborative capability of a multiagent system. Some methods model these by predefined rules. However, due to the nonstationary problem, the interactive relationship changes over time and cannot be well captured by rules. Other methods adopt a simple mechanism such as an attention network to select the neighbors the current agent should collaborate with. However, in large-scale multiagent systems, collaborative relationships are too complicated to be described by a simple attention network. We propose an adaptive and gated graph attention network (AGGAT), which models the interactive relationships between agents in a cascaded manner. In the AGGAT, we first propose a graph-based hard attention network that roughly filters irrelevant agents. Then, normal soft attention is adopted to decide the importance of each neighbor. Finally, gated attention further refines the collaborative relationship of agents. By using cascaded attention, the collaborative relationship of agents is precisely learned in a coarse-to-fine style. Extensive experiments are conducted on a variety of cooperative tasks. The results indicate that our proposed method outperforms state-of-the-art baselines.

Thymosin beta 4 alleviates non-alcoholic fatty liver by inhibiting ferroptosis via up-regulation of GPX4.

Thymosin beta 4 (Tß4) can improve the liver fibrosis and reduce inflammation, while the role of Tß4 in non-alcoholic fatty liver disease (NAFLD) whether mediated by ferroptosis remains unclear. A rat model of NAFLD was established on a high-fat diet (HFD), and rats were assigned ferroptosis inducer erastin and inhibitor Ferrostatin 1 (Fer-1). Subsequently, histopathology of the liver and the expression of ferroptosis-related genes in rat liver were detected. The steatosis of LO2 cells was induced by palmitic acid (PA) to reproduce the results of the rat experiment. The small interfering RNA (siRNA) was used to interfere with GPX4 expression to explore the influence on Tß4 function. Tß4 improved the inflammation, biochemical and lipid metabolism indexes, increased the antioxidant level, and inhibited abnormal accumulation of intracellular reactive oxygen species in HFD-induced NAFLD rats. Also, Tß4 improved PA-induced LO2 damage and inhibited apoptosis of PA-induced LO2 cells. Both in vivo and in vitro, Tß4 regulated expression of genes associated with ferroptosis, and Fer-1 treatment exaggerated the above effects of Tß4, while erastin attenuated the protective effect of Tß4. Moreover, siRNA GPX4 attenuated the protective effect of Tß4 on the rat liver and on the mitochondrial membrane integrity of LO2 cells. Interfered expression of GPX4 with siRNA also regulated the expression of Bcl-2, Bax, Caspase-3 and SOD1, which attenuated therapeutic effect of Tß4 on rat liver and LO2 cells. This study revealed that Tß4 protects hepatocytes by inhibiting the GPX4-mediated ferroptosis pathway, which provides a new strategy and target for the treatment of NAFLD.

Photosynthesis Performance and Antioxidative Enzymes Response of Melia azedarach and Ligustrum lucidum Plants Under Pb-Zn Mine Tailing Conditions.

Lead-zinc (Pb-Zn) mine tailings pose a great risk to the natural environment and human health because of their high toxicity. In this study, the responses of photosynthesis, chlorophyll fluorescence, and antioxidative enzyme of Melia azedarach and Ligustrum lucidum in the soil contaminated by Pb-Zn mine tailings were investigated. Results showed that Pb-Zn mine tailings significantly reduced net photosynthetic rates and leaf photosynthetic pigment content of both trees, and the reduction of net photosynthetic rates was mainly caused by their biochemical limitation (BL). The chlorophyll fluorescence parameters from Pb-Zn tailing stressed leaves indicated that Pb-Zn tailings affected PSII activity which was evident from the change values of energy fluxes per reaction center (RC): probability that an electron moves further than QA - (ETO/TRO), maximum quantum yield for primary photochemistry (TRO/ABS), the density of PSII RC per excited cross-section (RC/CSO), the absorption of antenna chlorophylls per PSII RC (ABS/RC), and the turnover number of QA reduction events (N). Pb-Zn mine tailings also affected the oxidation and reduction of PSI, which resulted in a great increase of reactive oxygen species (ROS) contents and then stimulated the rate of lipid peroxidation. Both trees exhibited certain antioxidative defense mechanisms as elevated superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, then declined under high level of Pb-Zn tailing treatment. Comparatively, L. lucidum showed less extent effect on photosynthesis and higher antioxidative enzyme activities than M. azedarach; thus L. lucidum was more tolerant than M. azedarach at least under the described Pb-Zn tailing treatment. These results indicate that the effect of Pb-Zn mine tailings on photosynthesis performance mainly related to imbalance of the PSII activity and PSI redox state in both trees. We propose that M. azedarach and L. lucidum could relieve the oxidative stress for phytoremediation under the appropriate Pb-Zn mine tailing content.

Photosystem II of Ligustrum lucidum in response to different levels of manganese exposure.

The toxic effect of excessive manganese (Mn) on photosystem II (PSII) of woody species remains largely unexplored. In this study, five Mn concentrations (0, 12, 24, 36, and 48 mM) were used, and the toxicity of Mn on PSII behavior in leaves of Ligustrum lucidum was investigated using in vivo chlorophyll fluorescence transients. Results showed that excessive Mn levels induced positive L- and K- bands. Variable fluorescence at 2 ms (VJ) and 30 ms (VI), absorption flux (ABS/RC), trapped energy flux (TRo/RC), and dissipated energy flux (DIo/RC) increased in Mn-treated leaves, whereas the performance index (PIABS), electron transport flux (ETo/RC), maximum quantum yield (φPo), quantum yield of electron transport (φEo), and probability that an electron moves further than QA- (ψo) decreased. Also, excessive Mn significantly decreased the net photosynthesis rate and increased intercellular CO2 concentration. The results indicated that Mn blocked the electron transfer from the donor side to the acceptor side in PSII, which might be associated with the accumulation of QA-, hence limiting the net photosynthetic rate.

Algorithm and VLSI Architecture Design of Low-Power SPIHT Decoder for mHealth Applications.

A real-time cost and power-efficient (CPE) set partitioning in hierarchical trees (SPIHT) decoder design with low hardware complexity and low-power dissipation is introduced in one-dimension (1-D) wavelet-based quality-assured electrocardiograph (ECG) compression systems for mobile health (mHealth) applications. However, current SPIHT coding architectures are designed for image/video processing. These architectures require a large amount of memory as well as complicated sorting algorithms, which both require time-consuming tasks and are unsuitable for mobile ECG applications. Based on our previously modified SPIHT coding work, which used flags and check bits to reduce memory requirements and coding complexity by merging three search processes into one step. Therefore, to achieve the real-time design goal for mobile ECG applications, in this paper, we first introduce a hardware-oriented SPIHT decoding algorithm that is suitable for decoding the previously presented SPIHT coding work. Accordingly, an appropriate low-power hardware architecture is developed to implement a real-time high-performance and low-cost SPIHT VLSI design for our proposed decoder algorithm, which is appropriate for mobile ECG applications. Using the distinct ECG signals in the MIT-BIH arrhythmia database (sampling rate of 360 Hz), the final simulation and VLSI implementation results reveal that the proposed CPE SPIHT decoder design outperforms the state-of-the-art designs in terms of the average decoding time, the decoding quality, the VLSI speed, and the power consumption. Most importantly, the design can be exploited to a 1-D 1024 × 1 wavelet-based quality-assured ECG data compression system.

Effects of cadmium on photosynthesis of Schima superba young plant detected by chlorophyll fluorescence.

Contamination by heavy metals has become a serious environmental pollution issue today due to its potential threat to plant, wildlife, and human health. Photosynthesis, a process in which light energy is used to produce sugar and other organic compounds, is sensitive to heavy metals. In the present study, the response of photosynthetic process and carbon assimilation of Schima superba was investigated under cadmium (Cd) stress. Three Cd concentrations (0, 300, and 600 mg kg-1) were used designated as control (CK), low Cd (L1), and high Cd treatment (L2) of plants. Results showed that photosystem II (PSII) acceptor and donor side electron transport were more easily blocked in treatment compared to control, and L2 have more significant changes than L1. A substantial decrease of 820 nm reflection curve absorption was observed both in L1 and L2 treatments. Special energy fluxes showed significant difference between the control group and the treated group, which indicated that low concentration Cd stress can cause decrease in quantum yield of PSII in plants studied. Non-stomatal factors resulted in a decrease in net photosynthetic rate and a decrease in photosystem activity. Our results suggested that Cd can damage structure and function of the photosynthesis of S. superba young plants.

Combination of gemcitabine and erlotinib inhibits recurrent pancreatic cancer growth in mice via the JAK-STAT pathway.

Compared to single gemcitabine treatment, the combination of gemcitabine and erlotinib has shown effective response in patients with locally advanced or metastatic pancreatic cancer. However, the combination therapy has not proven effective in patients with pancreatic cancer after R0 or R1 resection. In the present study, a nude mice model of orthotopic xenotransplantation after tumor resection was established using pancreatic cancer cell lines, BxPC-3 and PANC­1. Mice were divided in four groups (each with n=12) and were treated as follows: the control group received a placebo via intraperitoneal injection (i.p.), while the other three groups were treated with gemcitabine (50 mg/kg i.p., twice a week), erlotinib (50 mg/kg oral gavage, once every three days), and combined treatment of gemcitabine and erlotinib, respectively. The treatment lasted for 21 days, after which all mice were sacrificed and tumors were examined ex vivo. We determined that the combination of gemcitabine and erlotinib inhibited recurrent tumor growth and induced apoptosis in vivo by downregulating phosphorylation levels of JAKs and STATs, which in turn downregulated the downstream proteins HIF­1α and cyclin D1, and upregulated caspase­9 and caspase­3 expression. To sum up, the combination of gemcitabine with erlotinib was effective in treating patients with pancreatic cancer after R0 or R1 resection.