Amyloid β (Aβ) is considered to be responsible for the pathogenesis of Alzheimer's disease (AD). Mitochondrial and ER apoptotic pathways are considered to be involved in this process. Galantamine is ...an acetylcholinesterase (AChE) inhibitor widely used for patients with AD. In this study, we investigated the neuroprotective effects of galantamine on Aβ25–35-induced apoptosis in PC12 cells and the underlying mechanisms. Exposure of PC12 cells to 20μM Aβ25–35 caused significant cell viability loss and apoptosis, Aβ aggregation, mitochondrial and ER morphological changes, as well as mitochondrial membrane potential dissipation, reactive oxygen species (ROS) production, intracellular calcium elevation, and cytochrome c release from mitochondria. Pretreatment with 10μM galantamine for 24h prior to Aβ25–35 exposure significantly reduced Aβ25–35-induced apoptosis not only by preventing Aβ aggregation, mitochondrial and ER morphological changes, mitochondrial membrane potential dissipation, ROS production, intracellular calcium elevation, and cytochrome c release, but also via reversing Bcl-2/Bax ratio and suppressing the activity of GADD153, Grp78/94, caspase-9, caspase-12, and caspase-3. All these data indicate that galantamine protects PC12 cells against Aβ25–35-induced apoptosis by preventing mitochondrial dysfunction and endoplasmic reticulum (ER) stress.
This paper presents an analytic lower bound of ergodic capacity for distributed MIMO (D-MIMO) systems that experience not only Rician fading but also shadowing effects of Lognormal distributed. In ...particularly, we consider that the Rician fading channel is spatially correlated at both transmitter and receiver. In the communication environment corresponding to this setting, the angle spread at the transmitter and the angle spread at the receiver are both insufficient, and the non-fading components co-exists with the fading components. Such communication environment is very common. In the process of deriving the analytic lower bound, in order to avoid Hayakawa polynomials that cannot be analytically expressed, non-central quadratic forms are transformed to non-central Wishart matrices by use of inequality. The validity of the presented lower bound is verified by computer simulations. The simulation results show the influence of the number of radio ports at the transmitter, the number of antennas at the transmitter or receiver, correlation level (angle spreads) and Rician K-factor on the capacity of systems. In all cases, the presented bound remains tight across the entire signal-to-noise ratio (SNR) regime.
Secretion of leptin from adipocytes communicates body energy status to the brain by activating the leptin receptor long form (LRb). LRb regulates energy homeostasis and neuroendocrine function; the ...absence of LRb in db/db mice results in obesity, impaired growth, infertility and diabetes. Tyr 1138 of LRb mediates activation of the transcription factor STAT3 during leptin action. To investigate the contribution of STAT3 signalling to leptin action in vivo, we replaced the gene encoding the leptin receptor (lepr) in mice with an allele coding for a replacement of Tyr 1138 in LRb with a serine residue (leprS1138) that specifically disrupts the LRb-STAT3 signal. Here we show that, like db/db mice, leprS1138 homozygotes (s/s) are hyperphagic and obese. However, whereas db/db mice are infertile, short and diabetic, s/s mice are fertile, long and less hyperglycaemic. Furthermore, hypothalamic expression of neuropeptide Y (NPY) is elevated in db/db mice but not s/s mice, whereas the hypothalamic melanocortin system is suppressed in both db/db and s/s mice. LRb-STAT3 signalling thus mediates the effects of leptin on melanocortin production and body energy homeostasis, whereas distinct LRb signals regulate NPY and the control of fertility, growth and glucose homeostasis.
The magnesium alloy was made into orthopedic steel plates to repair tibial fractures of New Zealand white rabbits and to explore the biocompatibility, degradation behavior, and mechanical properties ...of the magnesium alloy plates in repairing fractures in vivo. Fifty-four rabbits were randomly divided into experimental, control, and sham-operated groups. Tibial fractures in the experimental and the control groups were fixed with magnesium alloy and titanium alloy plates, respectively, and only bone tunnels were established without any implants in the sham-operated group. The concentrations of serum alanine transaminase, creatinine (CREA), creatine kinase (CK), and magnesium ion were measured before and 1 day, 1, 2, 4, 8, and 16 weeks after operation, respectively, to evaluate the biocompatibility of magnesium alloy plates. The corrosion products and components were observed using a scanning electron microscope with an energy-dispersive spectroscopy system, and the corrosion rate was observed by weight loss testing. Then the degradation behavior of magnesium alloy plate was analyzed. Analysis of mechanical properties of magnesium alloy plates was done by four-point bending tests. There were no statistically significant differences in serum alanine transaminase, CREA, or CK at each time point among the three groups (P>0.05). The degradation behavior of the magnesium alloy plates increased with the longer implantation time. The four-point bending test results indicated that the mechanical properties of magnesium alloy plates decreased gradually during the degradation. The results showed that magnesium alloy plates implanted into rabbit tibias degrade gradually with the implantation time, and the mechanical properties of the magnesium alloy weaken gradually during the degradation. Meanwhile, the magnesium alloy plate had excellent biocompatibility and biosafety in the process of degradation in vivo.
To fully utilize the frequency regulation (FR) capability of wind turbines (WTs) and to avoid a secondary frequency drop caused by the rotor speed recovery, this paper firstly proposes an FR ...capability evaluation method for wind farms based on the principle of equal rotational kinetic energy of WTs, and analyses the essence of cooperative rotor speed recovery for WTs. Based on these, a cooperative synthetic inertia control (CSIC) for wind farms considering FR capability is proposed. By introducing the cooperative coefficient, the CSIC can fully utilize the FR capability of WTs, maintain the fast response of WTs with synthetic inertia control, and reduce communication requirements for the wind farm control center. By directly compensating the auxiliary FR power of WTs, the CSIC realizes the cooperative rotor speed recovery for WTs between different wind farms, avoiding a secondary frequency drop and a complex schedule of rotor speed recovery for multiple WTs. Finally, the simulation results verify the effectiveness and feasibility of the proposed control.
Vegetation growth is affected by both climate changes and human activities. In this study, we investigated the vegetation growth response to climate change (precipitation and temperature) and human ...activities in nine subregions and for nine vegetation types in China from 1982 to 2015. The normalized difference vegetation index (NDVI) and the RESTREND method based on a multiple linear regression model were employed to this end. An overall increasing trend in the NDVI was observed in recent decades, and the fastest increases were identified in southern China (TrendNDVI = +0.0190) and evergreen broad-leaved forests (TrendNDVI = +0.0152). For >66% of China, vegetation is more sensitive to temperature and less sensitive to precipitation based on the regression coefficients. The water demand for vegetative growth increased significantly from 1999 to 2015 with global warming, especially in parts of the temperate zone. We defined a relative change in the residual trend to quantify the impact of human activities on vegetation. RESTRENDNDVI/NDVI in two periods (P1, 1982–1998 and P2, 1999–2015) markedly increased, indicating that human activities play a key role in the reversal of land degradation.
Vertical diversity of sediment bacterial communities in 2 different trophic states (macrophyte-dominated and algae-dominated) of the large shallow eutrophic Lake Taihu, China, were investigated using ...denaturing gradient gel electrophoresis (DGGE) and 16S rRNA sequence analysis. Clustering analysis of DGGE profiles showed that different clusters were recognized in different depths of sediment cores in the 2 lake trophic states. Analyses of the bacterial diversity, as estimated by the Shannon index (H'), showed that different sediment layers of the macrophyte-dominated state had higher diversity than the algae-dominated state. In addition, bacterial diversity of the sediment in the macrophyte-dominated state changed abruptly throughout the layers, but bacterial diversity of the algae-dominated state decreased gradually with sediment depth. Phylogenetic analysis showed that Proteobacteria was the most abundant phylum in the middle sediment of the 2 lake trophic states. In the macrophyte-dominated state, clone sequences related to Betaproteobacteria (50.0%) were the most abundant, followed by Epsilonproteobacteria (21.1%), Acidobacteria (7.9%), Deltaproteobacteria (7.9%), Chloroflexi (7.9%), and Bacteroidetes (5.3%); whereas in the algae-dominated state, sequences affiliated with Betaproteobacteria (84.4%) were predominant, followed by Deltaproteobacteria (12.5%) and Acidobacteria (3.1%). Canonical correspondence analysis showed that organic matter and pH play key roles in driving the vertical changes of bacterial community composition.
Alcohol Use Disorder (AUD) is one of the most prevalent mental disorders worldwide. Considering the widespread occurrence of AUD, a reliable, cheap, non-invasive biomarker of alcohol consumption is ...desired by healthcare providers, clinicians, researchers, public health and criminal justice officials. microRNAs could serve as such biomarkers. They are easily detectable in saliva, which can be sampled from individuals in a non-invasive manner. Moreover, microRNAs expression is dynamically regulated by environmental factors, including alcohol. Since excessive alcohol consumption is a hallmark of alcohol abuse, we have profiled microRNA expression in the saliva of chronic, heavy alcohol abusers using microRNA microarrays. We observed significant changes in salivary microRNA expression caused by excessive alcohol consumption. These changes fell into three categories: downregulated microRNAs, upregulated microRNAs, and microRNAs upregulated
. Analysis of these combinatorial changes in microRNA expression suggests dysregulation of specific biological pathways leading to impairment of the immune system and development of several types of epithelial cancer. Moreover, some of the altered microRNAs are also modulators of inflammation, suggesting their contribution to pro-inflammatory mechanisms of alcohol actions. Establishment of the cellular source of microRNAs in saliva corroborated these results. We determined that most of the microRNAs in saliva come from two types of cells: leukocytes involved in immune responses and inflammation, and buccal cells, involved in development of epithelial, oral cancers. In summary, we propose that microRNA profiling in saliva can be a useful, non-invasive biomarker allowing the monitoring of alcohol abuse, as well as alcohol-related inflammation and early detection of cancer.
Long-distance transmission of renewable energy
via
DC is currently a more economical transmission scheme. As the proportion of renewable energy at the generation end continues to rise, the inertia ...and damping level of the system is reduced, causing serious frequency-related issues. This paper first analyzes the working principle and control method of the LCC-HVDC system, summarizes the frequency control methods of the sending end power grid and their existing problems, and proposes a frequency control scheme for the LCC-HVDC sending end system based on the concept of rapid power compensation (RPC). Finally, the LCC-HVDC system model integrated with the large-capacity wind farm and thermal power plant is built in MATLAB/Simulink. Under conditions of load power fluctuation and sudden wind speed change, the proposed strategy fully utilizes the spare capacity of the system, effectively improves the frequency indexes of the system, and improves the frequency characteristics of the renewable energy sending end grid.
The mammalian olfactory epithelium (OE) has a unique stem cell or progenitor niche, which is responsible for the constant peripheral neurogenesis throughout the lifespan of the animal. However, ...neither the signals that regulate the behavior of these cells nor the lineage properties of the OE stem cells are well understood. Multiple Wnt signaling components exhibit dynamic expression patterns in the developing OE. We generated Wnt signaling reporter TOPeGFP transgenic mice and found TOPeGFP activation predominantly in proliferating Sox2(+) OE basal cells during early postnatal development. FACS-isolated TOPeGFP(+) OE basal cells are required, but are not sufficient, for formation of spheres. Wnt3a significantly promotes the proliferation of the Sox2(+) OE sphere cells. Wnt-stimulated OE sphere cells maintain their multipotency and can differentiate into most types of neuronal and non-neuronal epithelial cells. Also, Wnt activators shift the production of differentiated cells toward olfactory sensory neurons. Moreover, TOPeGFP(+) cells are robustly increased in the adult OE after injury. In vivo administration of Wnt modulators significantly alters the regeneration potential. This study demonstrates the role of the canonical Wnt signaling pathway in the regulation of OE stem cells or progenitors during development and regeneration.
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