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Background: Exposure to air pollution is associated with an increased risk of all-cause mortality in older adults. Promoting physical activity (PA) and avoiding sedentary behavior (SB) serve as key strategies to maintain and improve human health. However, ambient air pollution can adversely affect PA and SB, increasing the risks of health problems. This study aimed to visualize national spatial patterns of average AQI concentration, PA, and SB distributions and to examine the associations between air pollution and PA and SB in a national sample of Chinese older adults aged 60 years or older. Methods: We analyzed the data of the China Longitudinal Aging Social Survey 2020 (CLASS 2020), which sampled 11,399 older men and women from 30 cities in China. Moderate, vigorous, and light PA and SB were measured using the Chinese version of the International Physical Activity Questionnaire-Short Form (IPAQ-C). The environmental measures included the average hourly air quality index (AQI), PM2.5, PM10, and NO2 (µg/m3). The data were analyzed using multivariable linear regression. Results: Increases in the standard deviations (±SD) of AQI, PM2.5, PM10, and NO2 concentrations were associated with decreases in MVPA per week of −2.34 (95%CI = −3.36, −1.32), −2.58 (95%CI = −3.61, −1.55), −1.96 (95%CI = −3.05, −0.08), and −1.19 (95%CI = −2.06, −0.31) and decreases in LPA per week of −6.06 (95%CI = −7.15, −4.97), −4.86 (95%CI = −5.88, −3.85), −4.78 (95%CI = −5.89, −3.68), and −4.59 (95%CI = −5.57, −3.61) h/week, respectively. Increases in one SD of AQI, PM2.5, PM10, and NO2 were associated with increases in SB per week of 1.32 (95%CI = 0.77, 1.88), 0.62 (95%CI = 0.09, 1.14), 1.03 (95%CI = 0.48, 1.59), and 0.98 (95%CI = 0.46, 1.49) h/week, respectively. Conclusions: The spatial distributions of the average AQI concentration, MVPA, LPA, and SB are useful and allow environmental and health policymakers to identify the areas with the highest priority air pollution environmental equality concerns. AQI was positively associated with MVPA and LPA, and it was negatively associated with SB among older adults. AQI, PM2.5, PM10, and NO2 were hardly associated with women’s average time spent engaged in MVPA. Region-specific and multi-level health policy options are needed to reduce ambient air pollution by taking different types of pollutants into account in order to avoid changes in PA and SB in this population, especially in locations with high air pollution concentrations.

Content caching in wireless edge is considered to be a feasible approach to improve the user’s quality of experience by caching popular multimedia content from data center. In this letter, we focus on movie on-demand streaming from Internet-based servers and propose a novel proactive caching strategy over time in small cell network. First, it constructs a weighted feature matrix (WFM) and estimates content popularity in terms of spatiotemporal variation using content-aware WFM (CWFM). According to estimated content popularity, the CWFM-based proactive caching algorithm makes a caching decision by cooperatively caching the contents with a approach of linear programming and variable recovery to minimize the average delivery latency (ADL) in each time slot. The simulation results show that our algorithm improves the performance in terms of ADL based on MovieLens data set.

In this paper, we propose a W-band 8-quadrature-amplitude-modulation (8QAM) frequency tripling photonic vector millimeter-wave (mm-wave) signal generation method by using a phase modulator (PM) with only amplitude pre-coding. The PM is driven by 2-Gbaud 8QAM-modulated amplitude precoded signal at 25 GHz. Instead of phase pre-coding, we only need to reverse the real part of the signal at the receiver after photo detector (PD). The structure of the transmitter and the structure of the receiver are simple. The frequency tripling scheme is completed by numerical simulation, the output optical spectrum is consistent with the theoretical analysis, and bit-error-ratio (BER) curves indicate that the put forward 75 GHz 8QAM vector signal generation technique has good performance. The BER of 6 Gbit/s 75 GHz 8QAM vector mm-wave signal is below 3.8 × 10-3 after 12 km optical fiber transmission. For all we know, it is the first time to report on the generation of high-order QAM photonic mm-wave signal with odd times of RF frequency by using a single external modulator.

In this paper, we propose a novel quadrature phase-shift keying (QPSK) vector millimeter-wave (mm-wave) signal generation based on odd times of frequency without precoding. The radio frequency (RF) vector signal generation module is universal for the generation of millimeter-wave signal with any odd frequency multiplication. Instead of phase precoding, the phases of electrical mm-wave signal are multiplied by the frequency multiplication number at the receiver after carrier phase estimation. The frequency tripling, quintupling, and septupling schemes are achieved by simulation, and bit-error-ratio curves demonstrate that the proposed QPSK vector mm-wave signal generation scheme works well.

In this paper, we propose a Packet Cache-Forward (PCF) method based on improved Bayesian outlier detection to eliminate out-of-order packets caused by transmission path drastically degradation during handover events in the moving satellite networks, for improving the performance of TCP. The proposed method uses an access node satellite to cache all received packets in a short time when handover occurs and forward them out in order. To calculate the cache time accurately, this paper establishes the Bayesian based mixture model for detecting delay outliers of the entire handover scheme. In view of the outliers' misjudgment, an updated classification threshold and the sliding window has been suggested to correct category collections and model parameters for the purpose of quickly identifying exact compensation delay in the varied network load statuses. Simulation shows that, comparing to average processing delay detection method, the average accuracy rate was scaled up by about 4.0%, and there is about 5.5% cut in error rate in the meantime. It also behaves well even though testing with big dataset. Benefiting from the advantage of the proposed scheme in terms of performance, comparing to conventional independent handover and network controlled synchronized handover in simulated LEO satellite networks, the proposed independent handover with PCF eliminates packet out-of-order issue to get better improvement on congestion window. Eventually the average delay decreases more than 70% and TCP performance has improved more than 300%.

Maximum traffic intensity supported by a low earth orbit mobile satellite system (LEO-MSS) is important in practical application for providing satisfactory service. Applying fix channel reservation with first in first out queueing handover scheme into LEO-MSS, a novel analytical approach is proposed for determining the maximum traffic intensity under pre-set quality of service (QoS) constraints on new call blocking probability and handover failure probability. The relationship between QoS constraints and maximum traffic intensity is established. The expression of maximum traffic intensity is then deduced. The optimal number of reserved channels is obtained. By comparing the results between the proposed approach and existing method, the correctness of the proposed approach is verified. The proposed approach greatly reduces the calculation complexity. Lastly, the accuracy of the analysis has been verified by computer simulations.

Magnetofluorescent nanocomposites (MFNCs) providing a single nanoscale platform with multimodal properties are gaining momentum in biological manipulation, biomedical imaging and therapy. In this work, we report the preparation of MFNCs integrating MnFe2O4 magnetic nanoparticles (MNPs), CuInS2/ZnS quantum dots (QDs) and poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PEG-PLGA) in a tetrahydrofuran (THF)/water solvent system. Through sonication and quick solvent displacement, multiple nanoparticles of each type are co-encapsulated within the hydrophobic core of PEG-PLGA micelles. The developed fabrication process is simple and fast. Moreover, due to the low toxicity of CuInS2/ZnS QDs, the fabrication process is environmentally benign. The fabricated MFNCs were further characterized regarding their fundamental physical, chemical and biological properties. Results reveal that the MFNCs possess high (Mn + Fe) recovery rates, and the optical properties and magnetic relaxivity of the MFNCs are sensitive to the MNP:QD mass ratios in the fabrication. Furthermore, the MFNCs present excellent stability in aqueous solutions, minimal cytotoxicity, and capability for bioconjugation. This study opens an avenue for the MFNCs to be employed in broad biological or biomedical applications.

Summary Dysfunction of PTEN-induced kinase 1 (PINK1) or DJ-1 promotes neuronal death and is implicated in the pathogenesis of Parkinson’s disease, but the underlying mechanisms remain unclear. Given the roles of N-methyl-d-aspartate receptor (NMDAr)-mediated neurotoxicity in various brain disorders including cerebral ischemia and neurodegenerative diseases, we investigated the effects of PINK1 and DJ-1 on NMDAr function. Using protein overexpression and knockdown approaches, we showed that PINK1 increased NMDAr-mediated whole-cell currents by enhancing the function of NR2A-containing NMDAr subtype (NR2ACNR). However, DJ-1 decreased NMDAr-mediated currents, which was mediated through the inhibition of both NR2ACNR and NR2B-containing NMDAr subtype (NR2BCNR). We revealed that the knockdown of DJ-1 enhanced PTEN expression, which not only potentiated NR2BCNR function but also increased PINK1 expression that led to NR2ACNR potentiation. These results indicate that NMDAr function is differentially regulated by DJ-1-dependent signal pathways DJ-1/PTEN/NR2BCNR and DJ-1/PTEN/PINK1/NR2ACNR. Our results further showed that the suppression of DJ-1, while promoted NMDA-induced neuronal death through the overactivation of PTEN/NR2BCNR-dependent cell death pathway, induced a neuroprotective effect to counteract DJ-1 dysfunction-mediated neuronal death signaling through activating PTEN/PINK1/NR2ACNR cell survival–promoting pathway. Thus, PINK1 acts with DJ-1 in a common pathway to regulate NMDAr-mediated neuronal death. This study suggests that the DJ-1/PTEN/NR2BCNR and DJ-1/PTEN/PINK1/NR2ACNR pathways may represent potential therapeutic targets for the development of neuroprotection strategy in the treatment of brain injuries and neurodegenerative diseases such as Parkinson’s disease.

The widespread distribution of the tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10) in the adult brain suggests its role in a broad range of brain functions. Here we show evidence supporting a physical interaction of PTEN with a region in the third intracellular loop (3L4F) of the serotonin 5-HT2C receptor (5-HT2cR, formerly 5-HT1c receptor) in cell cultures. PTEN limits agonist-induced phosphorylation of 5-HT2cR through its protein phosphatase activity. We showed the probable existence of PTEN:5-HT2cR complexes in putative dopaminergic neurons in the rat ventral tegmental area (VTA), a brain region in which virtually all abused drugs exert rewarding effects by activating its dopamine neurons. We synthesized the interfering peptide Tat-3L4F, which is able to disrupt PTEN coupling with 5-HT2cR. Systemic application of Tat-3L4F or the 5-HT2cR agonist Ro600175 suppressed the increased firing rate of VTA dopaminergic neurons induced by delta9-tetrahydrocannabinol (THC), the psychoactive ingredient of marijuana. Using behavioral tests, we found that Tat-3L4F or Ro600175 blocks conditioned place preference of THC or nicotine, and that Ro600175, but not Tat-3L4F, produces anxiogenic effects, penile erection, hypophagia and motor functional suppression. These results suggest a potential strategy for treating drug addiction with the Tat-3L4F peptide.

Magnetofluorescent nanocomposites (MFNCs) providing a single nanoscale platform with multimodal properties are gaining momentum in biological manipulation, biomedical imaging and therapy. In this work, we report the preparation of MFNCs integrating MnFe2O4 magnetic nanoparticles (MNPs), CuInS2/ZnS quantum dots (QDs) and poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PEG-PLGA) in a tetrahydrofuran (THF)/water solvent system. Through sonication and quick solvent displacement, multiple nanoparticles of each type are co-encapsulated within the hydrophobic core of PEG-PLGA micelles. The developed fabrication process is simple and fast. Moreover, due to the low toxicity of CuInS2/ZnS QDs, the fabrication process is environmentally benign. The fabricated MFNCs were further characterized regarding their fundamental physical, chemical and biological properties. Results reveal that the MFNCs possess high (Mn + Fe) recovery rates, and the optical properties and magnetic relaxivity of the MFNCs are sensitive to the MNP:QD mass ratios in the fabrication. Furthermore, the MFNCs present excellent stability in aqueous solutions, minimal cytotoxicity, and capability for bioconjugation. This study opens an avenue for the MFNCs to be employed in broad biological or biomedical applications.

The tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10) is a lipid and protein phosphatase. We report here that PTEN physically associates with the NR1 and NR2B subunits of NMDA receptors (NMDARs) in rat hippocampus. Downregulating the protein expression of PTEN inhibits the function of extrasynaptic NMDARs and decreases NMDAR surface expression, suggesting a crucial role for endogenous PTEN in the modulation of NMDAR-mediated neuronal function. Reducing PTEN expression also enhances Akt/Bad phosphorylation in hippocampal neurons. Importantly, suppressing lipid and protein phosphatase activity of PTEN, respectively, activates Akt and inhibits extrasynaptic NMDAR activity and thereby protects against ischemic neuronal deathin vitroandin vivo. Thus, our study reveals a dual neuroprotective mechanism by which Akt/Bad and extrasynaptic NMDARs are regulated via downregulation of two distinct PTEN phosphatase activities and present the possibility of PTEN as a potential therapeutic target for stroke treatment.

A surface modification approach adopting polymer encapsulation was developed to prepare zwitterion-like quantum dots (ZWL-QDs). The fundamental physical, chemical, and biological properties of the ZWL-QDs were characterized. It is found that the ZWL-QDs almost preserve the quantum yield (QY) of native hydrophobic QDs in organic solvents, and also are compact in size (7 ~ 10 nm hydrodynamic diameter) and stable over wide pHs or in high salinity solutions. Further cellular study shows that the ZWL-QDs with a concentration less than 100 nM have a minimal cytotoxicity and thus are biocompatible. Characterizing and understanding these essential properties of the ZWL-QDs are an important step before employing them for various applications.

The developmental variation of 2-[125I]iodomelatonin binding sites in membrane preparations of the chicken spinal cords was investigated. In 19-day-old embryos, the maximum number of binding sites (Bmax) was the highest during the development. With the increase in age posthatch, the Bmax decreased gradually and significantly from 1-day-old to 4-month-old chickens. However, there were no significant changes in equilibrium dissociation constant (Kd) among all age-groups studied. To study the circadian variation, the 2-[125I]iodomelatonin binding sites in the spinal cords of 3-week-old chickens were determined at 4-hour intervals throughout a 24-hour period under a 12-hour light/12-hour dark cycle. There was a diurnal rhythm in both Bmax and Kd of [125I]iodomelatonin binding sites in which Bmax decreased and Kd increased in the dark period. The characteristics of developmental and circadian variation of melatonin receptors in the chicken spinal cord suggest that melatonin may exert a direct action on spinal cord functions and that it plays a more important role in the young animal.

In this paper, we designed a Reed-Solomon(240,K) structure for CMMB system,which was based on analyzing the coding theory of Reed-Solomon(RS) code in CMMB system,the design of encoder was taking advantage of FPGA,could complete coding for data stream from the upper layer quickly and efficiently.We also analyzed the structure of multipliers in RS encoder,that are simple and can achieve high speed operation. Finally,under the ModelSim6.2b,the coding function was simulated,The simulation results show that the designed structure has such advantages as high efficiency and low complexity with good coding performance,it is consistent with the theoretical analysis.

Dysfunction of PTEN-induced kinase 1 (PINK1) or DJ-1 promotes neuronal death and is implicated in the pathogenesis of Parkinson's disease, but the underlying mechanisms remain unclear. Given the roles of N-methyl-d-aspartate receptor (NMDAr)-mediated neurotoxicity in various brain disorders including cerebral ischemia and neurodegenerative diseases, we investigated the effects of PINK1 and DJ-1 on NMDAr function. Using protein overexpression and knockdown approaches, we showed that PINK1 increased NMDAr-mediated whole-cell currents by enhancing the function of NR2A-containing NMDAr subtype (NR2ACNR). However, DJ-1 decreased NMDAr-mediated currents, which was mediated through the inhibition of both NR2ACNR and NR2B-containing NMDAr subtype (NR2BCNR). We revealed that the knockdown of DJ-1 enhanced PTEN expression, which not only potentiated NR2BCNR function but also increased PINK1 expression that led to NR2ACNR potentiation. These results indicate that NMDAr function is differentially regulated by DJ-1-dependent signal pathways DJ-1/PTEN/NR2BCNR and DJ-1/PTEN/PINK1/NR2ACNR. Our results further showed that the suppression of DJ-1, while promoted NMDA-induced neuronal death through the overactivation of PTEN/NR2BCNR-dependent cell death pathway, induced a neuroprotective effect to counteract DJ-1 dysfunction-mediated neuronal death signaling through activating PTEN/PINK1/NR2ACNR cell survival-promoting pathway. Thus, PINK1 acts with DJ-1 in a common pathway to regulate NMDAr-mediated neuronal death. This study suggests that the DJ-1/PTEN/NR2BCNR and DJ-1/PTEN/PINK1/NR2ACNR pathways may represent potential therapeutic targets for the development of neuroprotection strategy in the treatment of brain injuries and neurodegenerative diseases such as Parkinson's disease.

Dysfunction of PTEN-induced kinase-1 (PINK1) is implicated in neurodegeneration. We report here that oxygen-glucose deprivation (OGD), an in vitro insult mimicking ischemic neuron injury, resulted in a significant reduction of PINK1 protein expression in cultured cortical neurons. The decrease of PINK1 expression was blocked by the antagonists of NMDA receptors. We revealed that the overactivation of NR2B-containing NMDA receptors (NR2BRs) was responsible for the OGD-induced PINK1 reduction. The overactivated NR2BRs also inhibited the phosphorylation, but not the protein expression, of the cell survival-promoting kinase Akt after OGD insult, indicating that OGD-induced reduction of PINK1 protein is specific in the injury paradigm. We further showed that enhancing the protein expression of PINK1 antagonized OGD-induced reduction of Akt phosphorylation, suggesting that Akt may be a downstream target of PINK1 in ischemic neuron injury. Importantly, we provided evidence that both NR2BR antagonist and PINK1 over-expression protected against OGD-induced neuronal death. These results suggest that the overactivation of NR2BRs may contribute to ischemic neuron death through suppressing PINK1-dependent survival signaling. Thus, selectively antagonizing NR2BR signal pathway-induced neurotoxicity may be a potential neuroprotection strategy.

The type A GABA receptors are thought to mediate synchronization of clock cell activity within the suprachiasmatic nuclei (SCN). Here we report that casein kinases I epsilon and delta (CKI epsilon and CKI delta), the crucial clock regulators, form a complex with GABA(A) receptors and inhibit the receptors' function within the SCN according to a circadian rhythm. These results indicate that circadian variation of the kinase-receptor association may mediate regulation of GABA(A) receptor function by CKI epsilon-CKI delta in the SCN.

Melatonin receptors in the rabbit spinal cord were studied. Using in vitro quantitative autoradiography we have localized and characterized 2-[ 125 I]iodomelatonin ([ 125 I]MEL) binding sites in the central gray substance (lamina X) of the rabbit spinal cord. Saturation study revealed a single class of high affinity binding sites in the central gray substance with an equilibrium dissociation constant ( K d ) o 38.8 ± 5.25 pM and a maximum number of binding sites of 5.69 ± 0.84 fmol/mg protein in the mid-light period. These [ 125 I]MEL binding sites were highly specific for melatonin. Coincubation with 10 μM or 50 μM guanosine 5′- O -(3-thiotriphosphate) produced a significant change in K d . These results suggest that melatonin receptors in the rabbit spinal cord are coupled to a guanine-nucleotide-bind protein (G-protein). Our studies suggest that melatonin exerts a direct action on the rabbit spinal cord.

Circadian regulation of GABA A receptor function by CKIe-CKIδ in the rat suprachiasmatic nuclei