Neuronal activity,synaptic transmission,and molecular changes in the basolateral amygdala play critical roles in fear memory.Cylindromatosis(CYLD)is a deubiquitinase that negatively regulates the nuclear factor kappa-...Neuronal activity,synaptic transmission,and molecular changes in the basolateral amygdala play critical roles in fear memory.Cylindromatosis(CYLD)is a deubiquitinase that negatively regulates the nuclear factor kappa-B pathway.CYLD is well studied in non-neuronal cells,yet underinvestigated in the brain,where it is highly expressed.Emerging studies have shown involvement of CYLD in the remodeling of glutamatergic synapses,neuroinflammation,fear memory,and anxiety-and autism-like behaviors.However,the precise role of CYLD in glutamatergic neurons is largely unknown.Here,we first proposed involvement of CYLD in cued fear expression.We next constructed transgenic model mice with specific deletion of Cyld from glutamatergic neurons.Our results show that glutamatergic CYLD deficiency exaggerated the expression of cued fear in only male mice.Further,loss of CYLD in glutamatergic neurons resulted in enhanced neuronal activation,impaired excitatory synaptic transmission,and altered levels of glutamate receptors accompanied by over-activation of microglia in the basolateral amygdala of male mice.Altogether,our study suggests a critical role of glutamatergic CYLD in maintaining normal neuronal,synaptic,and microglial activation.This may contribute,at least in part,to cued fear expression.展开更多
Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these...Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these muscles may not effectively engage any of the remaining neurons in the descending pathway.A previous study unexpectedly found that a brief clinical round of passive activity significantly increased volitional muscle activation,as measured by surface electromyography.In this study,we further explored the effect of passive activity on surface electromyographic signals during volitional control tasks among individuals with complete spinal cord injury.Eleven patients with chronic complete thoracic spinal cord injury were recruited.Surface electromyography data from eight major leg muscles were acquired and compared before and after the passive activity protocol.The results indicated that the passive activity led to an increased number of activated volitional muscles and an increased frequency of activation.Although the cumulative root mean square of surface electromyography amplitude for volitional control of movement showed a slight increase after passive activity,the difference was not statistically significant.These findings suggest that brief passive activity may enhance the ability to initiate volitional muscle activity during surface electromyography tasks and underscore the potential of passive activity for improving residual motor control among patients with motor complete spinal cord injury.展开更多
Taking the 13-point smoothed monthly sunspot number,Ri, and the deviation of the 13 associated monthly sunspot numbers from the smoothed one, Di, as a number-pair describing the global level of sunspot activity, the e...Taking the 13-point smoothed monthly sunspot number,Ri, and the deviation of the 13 associated monthly sunspot numbers from the smoothed one, Di, as a number-pair describing the global level of sunspot activity, the evolution of the level is statistically studied for the period from the month which is just 48 months before the minimum to the minimum in the descending phase, using the observed data of Solar Cycles 10 to 22. Our results show (1) for 46 months (94%) of the studied 49 months it is found that for a given month, the distribution of the 13 pairs which come from the 13 solar cycles on a log Ri - Di plane may be fitted by a straight line with a correlation coefficient larger than the critical one at confidence level a = 5%, and for 36 months (73%) the fitting is even better, for a = 1%; (2) time variations of these two parameters and their correlations in the studied period can be described respectively by functions of time, whose main trends may be expressed by a linear or simple curvilinear function; (3) the evolutionary path of the level of sunspot activity may be represented by a logarithmic function as log/~ = 0.704 lnDi - 0.291.展开更多
The relationships between solar flare parameters (total importance, time duration, flare index, and flux) and sunspot activity (R z ) as well as those between geomagnetic activity (aa index) and the flare parame...The relationships between solar flare parameters (total importance, time duration, flare index, and flux) and sunspot activity (R z ) as well as those between geomagnetic activity (aa index) and the flare parameters can be well described by an integral response model with the response time scales of about 8 and 13 months, respectively. Compared with linear relationships, the correlation coefficients of the flare parameters with R z , of aa with the flare parameters, and of aa with R z based on this model have increased about 6%, 17%, and 47% on average, respectively. The time delays between the flare parameters with respect to R z , aa to the flare parameters, and aa to R z at their peaks in a solar cycle can be predicted in part by this model (82%, 47%, and 78%, respectively). These results may be further improved when using a cosine filter with a wider window. It implies that solar flares are related to the accumulation of solar magnetic energy in the past through a time decay factor. The above results may help us to understand the mechanism of solar flares and to improve the prediction of the solar flares.展开更多
Climate change in the Arctic region is more rapid than that in other areas owing to Arctic amplification. To better understand climate change and the driving mechanisms, long-term historical reconstructions throughout...Climate change in the Arctic region is more rapid than that in other areas owing to Arctic amplification. To better understand climate change and the driving mechanisms, long-term historical reconstructions throughout the Holocene and high-resolution records of the past few hundred years are required. Intense anthropogenic activities in the Arctic have had a great impact on the local environment. Here, we review the Holocene climate change record, responses of the ecosystems to climate change, and the anthropogenic impacts on the environment based mainly on Chinese research from Ny-Alesund. Climate reconstruction studies from Svalbard have revealed several cold episodes during the Holocene, which are consistent with ice rafting events in the North Atlantic region and glacier activity from Greenland, Iceland, and Svalbard. The ecosystem also showed corresponding responses to climate change, especially during the late Holocene. Over recent decades, anthropogenic activities have caused serious pollution and deterioration to the local environment in Svalbard in areas frequented by people. Greater environmental protection is therefore needed to reduce the anthropogenic impacts on the local environment.展开更多
Vertical occurrence of soil urease activity along with ammonia content from three distinct regions viz. Deep forest region (No tidal action and wave attack occurs as it is furthest from river shore and it contains max...Vertical occurrence of soil urease activity along with ammonia content from three distinct regions viz. Deep forest region (No tidal action and wave attack occurs as it is furthest from river shore and it contains maximum content of organic carbon and minimum soil salinity and silicate concentration. In this zone plenty of pneumatophores, below ground root and dense vegetation are found), Rooted region (It is situated in between Deep forest region and Un-rooted region. This region contains only pneumatophores but it is devoid of long roots and vegetations. It faces wave attack and tidal action less than that of Un-rooted region) and Un-rooted region (It is closest to river shore and faces maximum wave attack and tidal action;it contains minimum organic carbon but maximum soil salinity and silicate concentration. This zone is totally devoid of any roots, pneumatophores and vegetations) of Sundarban mangrove forest ecosystem, India revealed an interesting explanation. Soil urease activity showed a decreasing pattern with increase in depth from the deep forest region of the Sundarban forest ecosystem. Soil urease activity was found to be more sensitive to soil temperature and pH rather than soil salinity. This ensured that soil urease along with the microbes present in the Sundarban forest ecosystem are more tolerant to fluctuation in salinity than that of temperature. Soil ammonia concentration was found to be directly governed by the soil urease activity [The regression equation is Ammonia in soil = -1.64 + 0.0402 Urease Activity (R-Sq = 62.9%, P < 0.001, n = 41)].展开更多
Studies on the periodic variation and the phase relationship between different solar activity indicators are useful for understanding the long-term evolution of solar activity cycles.Here we report the statistical ana...Studies on the periodic variation and the phase relationship between different solar activity indicators are useful for understanding the long-term evolution of solar activity cycles.Here we report the statistical analysis of grouped solar flare(GSF) and sunspot number(SN) during the time interval from January 1965 to March 2009.We find that,(1) the significant periodicities of both GSF and SN are related to the differential rotation periodicity,the quasi-biennial oscillation(QBO),and the eleven-year Schwabe cycle(ESC),but the specific values are not absolutely identical;(2) the ESC signal of GSF lags behind that of SN with an average of 7.8 months during the considered time interval,which implies that the systematic phase delays between GSF and SN originate from the inter-solar-cycle signal.Our results may provide evidence about the storage of magnetic energy in the corona.展开更多
Objective: To isolate and evaluate the antimicrobial activity of the active principle(s) from the ethyl acetate(EtOAc) extract of endophytic fungus Colietotrichum gloeosporioides(C.gloeosporioides) isolated from Sonne...Objective: To isolate and evaluate the antimicrobial activity of the active principle(s) from the ethyl acetate(EtOAc) extract of endophytic fungus Colietotrichum gloeosporioides(C.gloeosporioides) isolated from Sonneratia apetala. Methods: Water agar technique was used to isolate the fungus, and both microscopic and molecular techniques were used for identification of the strain. Potato dextrose broth was used to grow the fungus in large-scale. Reversed-phase preparative HPLC analysis was performed to isolate the major active compound, kojic acid. The EtOAc extract and kojic acid were screened for their antimicrobial activity against two Grampositive and two Gram-negative bacteria as well as a fungal strain using the resazurin 96-well microtitre plate antimicrobial assay. Results: The fungus C. gloeosporioides was isolated from the leaves of Sonneratia apetala. Initial identification of the fugal isolate was carried out using spore characteristics observed under the microscope. Subsequently, the ITS1-5.8 S-ITS2 sequencing was employed for species-level identification of the fungus C. gloeosporioides. Five litres of liquid culture of the fungus produced approximately 610 mg of a mixture of secondary metabolites.Kojic acid(1) was isolated as the main secondary metabolite present in the fungal extract, and the structure was confirmed by 1 D, 2 D NMR and mass spectrometry. The EtOAc extract and compound 1 exhibited considerable antimicrobial activity against all tested microorganisms.Whilst the minimum inhibitory concentration(MIC) values from the EtOAc extract ranged between 2.4×10^(-4)mg/mL and 2.5 mg/mL, those of kojic acid(1) were between 0.125 mg/mL and1 mg/mL. The EtOAc extract and kojic acid(1) were most active against Pseudomonas aeruginosa(MIC = 2.4×10^(-4). mg/mL) and Micrococcus luteus(MIC = 0.125 mg/mL), respectively. Conclusions:The results revealed that the endophytic fungus C. gloeosporioides could be a good source of commercially important kojic acid, which exhibited antimicrobial properties.展开更多
Populations of culturable microbes and activities of dehydrogenase & ?-D glucosidase were found maximum in surface soil and decreased with increase in depth in Sundarban mangrove environment.The maximum (13.529 X ...Populations of culturable microbes and activities of dehydrogenase & ?-D glucosidase were found maximum in surface soil and decreased with increase in depth in Sundarban mangrove environment.The maximum (13.529 X 106 C.F.U g-1 dry weight of soil) and minimum (11.547 X 106 C.F.U g-1 dry weight of soil) total microbial popu- lations in surface soil were recorded during po- st-monsoon and monsoon respectively. At 60 cm depth, the lower (6.396 X 106 C.F.U g-1 dry weight of soil) and higher (8.003 X 106 C.F.U g-1 dry weight of soil) numbers of total microbial populations were observed during monsoon and post-monsoon respectively. A decreasing trend of total microbial load, enzyme activities and nutrient status with organic carbon were found with increase in depth throughout the year. Present study revealed the relationship among depth integrated variations of physico-chemical compo- nents (viz. soil temperature, pH, moisture, orga- nic-C, .nitrogen, and available-P) and microbial populations as well as activity of dehydrogenase and ?-D glucosidase enzymes.展开更多
CuO was synthesized by thermal decomposition of Cu(NO3)2·3H2O at various temperatures and characterized by powder X-ray diffractometry(XRD) as well as scanning electron microscopy(SEM).The effects of calcination ...CuO was synthesized by thermal decomposition of Cu(NO3)2·3H2O at various temperatures and characterized by powder X-ray diffractometry(XRD) as well as scanning electron microscopy(SEM).The effects of calcination temperature,category of sacrificial reagent,initial sacrificial reagent concentration,and Ag loading content on the photocatalytic activity of the as-obtained CuO sample were investigated.The results show that the as-obtained CuO exhibits high activity for photocatalysis of H2 evolution reaction(HER) in oxalic acid solution under simulated sunlight irradiation.The highest photocatalytic activity of the as-obtained CuO was achieved at the calcination temperature of 1000℃,and oxalic acid was used as the sacrificial reagent with the concentration 0.05 mol/L.H2 evolution rate is as high as 2.98 mmol/(h·g) with 2%(mass fraction) loaded Ag.The possible photocatalytic reaction mechanism on the CuO photocatalyst for HER in oxalic acid solution was also discussed.展开更多
The atmospheric activity of the Sun and Sun-like stars is analyzed involving observations from the HK-project at the Mount Wilson Observatory, the California and Carnegie Planet Search Program at the Keck and Lick Obs...The atmospheric activity of the Sun and Sun-like stars is analyzed involving observations from the HK-project at the Mount Wilson Observatory, the California and Carnegie Planet Search Program at the Keck and Lick Observatories and the Magellan Planet Search Program at the Las Campanas Observatory. We show that for stars of E G and K spectral classes, the cyclic activity, similar to the 11-yr solar cycle, is different: it becomes more prominent in K-stars. Comparative study of Sun-like stars with different levels of chromospheric and coronal activity confirms that the Sun belongs to stars with a low level of chromospheric activity and stands apart among these stars by its minimum level of coronal radiation and minimum level of variations in photospheric flux.展开更多
Zirconia-supported CuO (CuO/ZrO2) composite photocatalysts were successfully synthesized via citric acid-assisted sol-gel technique. For comparison, CuO/ZrO2 materials were also prepared by solid state reaction and ...Zirconia-supported CuO (CuO/ZrO2) composite photocatalysts were successfully synthesized via citric acid-assisted sol-gel technique. For comparison, CuO/ZrO2 materials were also prepared by solid state reaction and co-precipitation method. The as-prepared powders were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), and thermogravimetric-differential thermal analysis (TG-DTA). The photocatalytic activity of CuO/ZrO2 catalyst was investigated based on the H2 evolution from oxalic acid solution under simulated sunlight irradiation. The effects of molar ratio of CuO to ZrO2, preparation method, phase change with the calcination temperature and the durability on the photocatalytic activity of the photocatalyst were investigated in detail. It is found that the optimal activity of photocatalytic H2 evolution (2.41 mmol.h i.g-~) can be obtained when CuO/ZrO2 composite photocatalyst is synthesized by sol-gel technique and the mole ratio of CuO to ZrO2 is 40%. The activity of copper oxide supported on monoclinic ZrO2 calcined at higher temperature is much higher than that on tetragonal ZrO2 calcined at lower temperature, and the best calcination temperature is 900 ℃.展开更多
The wavelet transform method for high-quality time-frequency analysis is applied to sets of observations of relative sunspot numbers and stellar chromosphere fluxes of 10 Sun-like stars. Wavelet analysis of solar data...The wavelet transform method for high-quality time-frequency analysis is applied to sets of observations of relative sunspot numbers and stellar chromosphere fluxes of 10 Sun-like stars. Wavelet analysis of solar data shows that in a certain interval of time there are several cycles of activity with pe- riods of duration which vary considerably from each other: from quasi-biennial cycles to lO0-yr cycles. Cyclic activity was detected in almost all Sun-like stars that we examined, even those that previously were not considered as stars with cyclic activity according to analysis using a Scargle periodogram. The durations of solar and stellar cycles significantly change during the observation period.展开更多
The effect of chitosan on the development of infection caused by Tobacco mosaic virus(TMV) in leaves of Nicotiana tabacum L. cv. Samsun has been studied. It was shown that the infectivity and viral coat protein conten...The effect of chitosan on the development of infection caused by Tobacco mosaic virus(TMV) in leaves of Nicotiana tabacum L. cv. Samsun has been studied. It was shown that the infectivity and viral coat protein content in leaves inoculated with a mixture of TMV(2 μg/mL) and chitosan(1 mg/mL) were lower in the early period of infection(3 days after inoculation), by 63% and 66% respectively, than in leaves inoculated with TMV only. Treatment of leaves with chitosan 24 h before inoculation with TMV also caused the antiviral effects, but these were less apparent than when the virus and polysaccharide were applied simultaneously. The inhibitory effects of the agent decreased as the infection progressed. Inoculation of leaves with TMV together with chitosan considerably enhanced the activity of hydrolases(proteases, RNases) in the leaves, in comparison with leaves inoculated with TMV alone. Electron microscope assays of phosphotungstic acid(PTA)-stained suspensions from infected tobacco leaves showed that, in addition to the normal TMV particles(18 nm in diameter, 300 nm long), these suspensions contained abnormal(swollen, "thin" and "short") virions. The highest number of abnormal virions was found in suspensions from leaves inoculated with a mixture of TMV and chitosan. Immuno-electron microscopy showed that "thin" virus particles, in contrast to the particles of normal diameter, lost the ability to bind to specific antiserum. It seems that the chitosan-induced activation of hydrolases stimulates the intracellular degradation of TMV particles and hence hydrolase activation may be considered to be one of the polysaccharide-mediated cellular defense mechanisms that limit virus accumulation in cells.展开更多
Sunflower seed meal peptide as one sort of bioactive peptide has intensively application prospects. However, preparation of low salt peptide from sunflower seed meal with high efficiency remains a challenge. In this s...Sunflower seed meal peptide as one sort of bioactive peptide has intensively application prospects. However, preparation of low salt peptide from sunflower seed meal with high efficiency remains a challenge. In this study, single and compound proteases were optimized to hydrolyze protein. Results showed that hydrolysis at pH 7.0 by proteases resulted in ash content in the range of 5.66%-7.37% and small peptides. Among all hydrolysis processes, sequential hydrolysis of Alcalase with Flavourzyme and Alcalase with Protamex showed higher nitrogen recovery ratio (67.66% and 66.49%, respectively). Furthermore, biological activities of peptides were investigated by testing their ABTS (2,2-azinobis (3-ethylben-zothiazoline-6-sulfonic acid) diammonium salt) radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazil) radical scavenging activity and angiotensin converting enzyme (ACE) inhibitory activity. Peptide hydrolyzed by Alcalase with Papain presented the highest antioxidant activity, followed by Alcalase with Protamex, with ABTS scavenging rate as 63.01% and 31.75%, and DPPH scavenging rate as 56.04% and 28.06%, respectively. Synchronously, peptide hydrolyzed by Alcalase with Protamex and Alcalase with Alcalase had the highest ACE inhibitory activity (56.74%, 56.76%). In conclusion, hydrolysis by proteases Alcalase with Protamex at pH 7.0 was the most effective method for the preparation of low salt peptide from sunflower seed meal, which could be an alternative for anti-oxidants and anti-vasoconstrictor.展开更多
Two primary solar-activity indicators- sunspot numbers (SNs) and sunspot areas (SAs) in the time interval from November 1874 to December 2012 - are used to determine the chaotic and fractal properties of solar act...Two primary solar-activity indicators- sunspot numbers (SNs) and sunspot areas (SAs) in the time interval from November 1874 to December 2012 - are used to determine the chaotic and fractal properties of solar activity. The results show that (1) the long-term solar activity is governed by a low-dimensional chaotic strange attractor, and its fractal motion shows a long-term persistence on large scales; (2) both the fractal dimension and maximal Lyapunov exponent of SAs are larger than those of SNs, implying that the dynamical system of SAs is more chaotic and complex than SNs; (3) the predictions of solar activity should only be done for short- to mid-term behaviors due to its intrinsic complexity; moreover, the predictability time of SAs is obviously smaller than that of SNs and previous results.展开更多
Baculoviruses are effective biocontrol agents except of their short persistence under sunlight conditions. Four promising additives containing different groups of antioxidants were tested on cotton plant foliage. Spod...Baculoviruses are effective biocontrol agents except of their short persistence under sunlight conditions. Four promising additives containing different groups of antioxidants were tested on cotton plant foliage. Spodoptera littoralis test insect and its nuclepolyhedrovirus (SpliNPV) are the standard material used in the investigation. Results are based on leaf-bioassays, to test Original Activity Remaining (OAR) and Lethal Infectivity Time to 50% (LIT50)of tested population of the virus after exposure to natural sunlight. The results showed that cacao additive at 10%, sustained 50% of virus activity for five days post application (113.11 hours) and three days and a half (83.33 hours) at 5% concentration. The virus alone treatment sustained 50% of its activity for only 24.07 hours. The obtained results suggested the possibility of prolonging the virus activity on plant foliage under field applications.展开更多
The HDPFF (heavy-disaster-period of forest fire) takes up 1 / 4-1 / 3 of all observation years, but the loss takes up 80-90% of all. The author studied the relations between forest fire activity in Heilongiiang Provin...The HDPFF (heavy-disaster-period of forest fire) takes up 1 / 4-1 / 3 of all observation years, but the loss takes up 80-90% of all. The author studied the relations between forest fire activity in Heilongiiang Province from 1950 to 1989 and activity of sunspot, SSTA (sea surface temperature abnormality) of the North Pacific Ocean. The study discovered that : (1 )there was a negative correlation between forest fire condition in Heilongjiang Province and annual average of sunspot relative numbers, furthermore, the heavy-disaster-period was prone to occur in valley year and the next year; (2) SSTA in the North Pacific Ocean markedly influenced the forest fire activity and the level of its conditions in Heilongjiang province.展开更多
We present a study of seven large solar proton events in the current solar cycle 24(from 2009 January up to the current date). They were recorded by the GOES spacecraft with the highest proton fluxes being over 200 ...We present a study of seven large solar proton events in the current solar cycle 24(from 2009 January up to the current date). They were recorded by the GOES spacecraft with the highest proton fluxes being over 200 pfu for energies 〉10 Me V. In situ particle measurements show that:(1) The profiles of the proton fluxes are highly dependent on the locations of their solar sources, namely flares or coronal mass ejections(CMEs), which confirms the "heliolongitude rules" associated with solar energetic particle fluxes;(2) The solar particle release(SPR) times fall in the decay phase of the flare emission, and are in accordance with the times when the CMEs travel to an average height of 7.9 solar radii; and(3) The time differences between the SPR and the flare peak are also dependent on the locations of the solar active regions. The results tend to support the scenario of proton acceleration by the CME-driven shock,even though there exists a possibility of particle acceleration at the flare site, with subsequent perpendicular diffusion of accelerated particles in the interplanetary magnetic field. We derive the integral time-of-maximum spectra of solar protons in two forms: a single power-law distribution and a power law roll-over with an exponential tail. It is found that the unique ground level enhancement that occurred in the event on 2012 May 17 displays the hardest spectrum and the largest roll-over energy which may explain why this event could extend to relativistic energies.展开更多
In this paper we present an approach for forecasting the imminent regional seismic activity by using geomagnetic data and Earth tide data. The time periods of seismic activity are the time periods around the Sun-Moon ...In this paper we present an approach for forecasting the imminent regional seismic activity by using geomagnetic data and Earth tide data. The time periods of seismic activity are the time periods around the Sun-Moon extreme of the diurnal average value of the tide vector module. For analyzing the geomagnetic data behaviour we use diurnal standard deviation of geomagnetic vector components F (North, East, Down) for calculating the time variance GeomagSignal. The Sun storm influence is avoided by using data for daily A-indexes (published by NOAA). The precursor signal for forecasting the incoming regional seismic activity is a simple function of the present and previous day GeomagSignal and A-indexes values. The reliability of the geomagnetic “when, regional” precursor is demonstrated by using statistical analysis of day difference between the times of “predicted” and occurred earthquakes. The base of the analysis is a natural hypothesis that the “predicted” earthquake is the one whose surface energy density in the monitoring point is bigger than the energy densities of all occurred earthquakes in the same period and region. The reliability of the approach was tested using the INTERMAGNET stations data located in Bulgaria, Panagurishte, PAG (Jan 1, 2008-Jan 29, 2014), Romania, Surlari, SUA (Jan 1, 2008-Jan 27, 2014), Italy, L’Aquila, AQU (Jan 1, 2008-May 30, 2013) in the time of EU IRSES BlackSeaHazNet (2011-2014) project. The steps of program for solving the “when, where and how” earthquake prediction problem are shortly described.展开更多
基金supported by the National Natural Science Foundation of China,Nos.32371065(to CL)and 32170950(to LY)the Natural Science Foundation of the Guangdong Province,No.2023A1515010899(to CL)the Science and Technology Projects in Guangzhou,Nos.2023A4J0578 and 2024A03J0180(to CW)。
文摘Neuronal activity,synaptic transmission,and molecular changes in the basolateral amygdala play critical roles in fear memory.Cylindromatosis(CYLD)is a deubiquitinase that negatively regulates the nuclear factor kappa-B pathway.CYLD is well studied in non-neuronal cells,yet underinvestigated in the brain,where it is highly expressed.Emerging studies have shown involvement of CYLD in the remodeling of glutamatergic synapses,neuroinflammation,fear memory,and anxiety-and autism-like behaviors.However,the precise role of CYLD in glutamatergic neurons is largely unknown.Here,we first proposed involvement of CYLD in cued fear expression.We next constructed transgenic model mice with specific deletion of Cyld from glutamatergic neurons.Our results show that glutamatergic CYLD deficiency exaggerated the expression of cued fear in only male mice.Further,loss of CYLD in glutamatergic neurons resulted in enhanced neuronal activation,impaired excitatory synaptic transmission,and altered levels of glutamate receptors accompanied by over-activation of microglia in the basolateral amygdala of male mice.Altogether,our study suggests a critical role of glutamatergic CYLD in maintaining normal neuronal,synaptic,and microglial activation.This may contribute,at least in part,to cued fear expression.
基金supported by the Fundamental Research Funds for Central Public Welfare Research Institute,No.2020CZ-5(to WS and GS)the National Natural Science Foundation of China,No.31970970(to JSR)Fundamental Research Funds for the Central Universities,No.YWF-23-YG-QB-010(to JSR)。
文摘Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these muscles may not effectively engage any of the remaining neurons in the descending pathway.A previous study unexpectedly found that a brief clinical round of passive activity significantly increased volitional muscle activation,as measured by surface electromyography.In this study,we further explored the effect of passive activity on surface electromyographic signals during volitional control tasks among individuals with complete spinal cord injury.Eleven patients with chronic complete thoracic spinal cord injury were recruited.Surface electromyography data from eight major leg muscles were acquired and compared before and after the passive activity protocol.The results indicated that the passive activity led to an increased number of activated volitional muscles and an increased frequency of activation.Although the cumulative root mean square of surface electromyography amplitude for volitional control of movement showed a slight increase after passive activity,the difference was not statistically significant.These findings suggest that brief passive activity may enhance the ability to initiate volitional muscle activity during surface electromyography tasks and underscore the potential of passive activity for improving residual motor control among patients with motor complete spinal cord injury.
基金Supported by the National Natural Science Foundation of China.
文摘Taking the 13-point smoothed monthly sunspot number,Ri, and the deviation of the 13 associated monthly sunspot numbers from the smoothed one, Di, as a number-pair describing the global level of sunspot activity, the evolution of the level is statistically studied for the period from the month which is just 48 months before the minimum to the minimum in the descending phase, using the observed data of Solar Cycles 10 to 22. Our results show (1) for 46 months (94%) of the studied 49 months it is found that for a given month, the distribution of the 13 pairs which come from the 13 solar cycles on a log Ri - Di plane may be fitted by a straight line with a correlation coefficient larger than the critical one at confidence level a = 5%, and for 36 months (73%) the fitting is even better, for a = 1%; (2) time variations of these two parameters and their correlations in the studied period can be described respectively by functions of time, whose main trends may be expressed by a linear or simple curvilinear function; (3) the evolutionary path of the level of sunspot activity may be represented by a logarithmic function as log/~ = 0.704 lnDi - 0.291.
基金supported by the National Natural Science Foundation of China (Grant Nos.10973020, 40890161 and 10921303)the National Basic Research Program of China (973 Program, Grant No.2011CB811406)
文摘The relationships between solar flare parameters (total importance, time duration, flare index, and flux) and sunspot activity (R z ) as well as those between geomagnetic activity (aa index) and the flare parameters can be well described by an integral response model with the response time scales of about 8 and 13 months, respectively. Compared with linear relationships, the correlation coefficients of the flare parameters with R z , of aa with the flare parameters, and of aa with R z based on this model have increased about 6%, 17%, and 47% on average, respectively. The time delays between the flare parameters with respect to R z , aa to the flare parameters, and aa to R z at their peaks in a solar cycle can be predicted in part by this model (82%, 47%, and 78%, respectively). These results may be further improved when using a cosine filter with a wider window. It implies that solar flares are related to the accumulation of solar magnetic energy in the past through a time decay factor. The above results may help us to understand the mechanism of solar flares and to improve the prediction of the solar flares.
基金supported by the Chinese Polar Environment Comprehensive Investigation and Assessment Program (Grant nos. CHINARE2017-02-01, CHINARE2017-04-04, and CHINARE 2017-04-03)
文摘Climate change in the Arctic region is more rapid than that in other areas owing to Arctic amplification. To better understand climate change and the driving mechanisms, long-term historical reconstructions throughout the Holocene and high-resolution records of the past few hundred years are required. Intense anthropogenic activities in the Arctic have had a great impact on the local environment. Here, we review the Holocene climate change record, responses of the ecosystems to climate change, and the anthropogenic impacts on the environment based mainly on Chinese research from Ny-Alesund. Climate reconstruction studies from Svalbard have revealed several cold episodes during the Holocene, which are consistent with ice rafting events in the North Atlantic region and glacier activity from Greenland, Iceland, and Svalbard. The ecosystem also showed corresponding responses to climate change, especially during the late Holocene. Over recent decades, anthropogenic activities have caused serious pollution and deterioration to the local environment in Svalbard in areas frequented by people. Greater environmental protection is therefore needed to reduce the anthropogenic impacts on the local environment.
文摘Vertical occurrence of soil urease activity along with ammonia content from three distinct regions viz. Deep forest region (No tidal action and wave attack occurs as it is furthest from river shore and it contains maximum content of organic carbon and minimum soil salinity and silicate concentration. In this zone plenty of pneumatophores, below ground root and dense vegetation are found), Rooted region (It is situated in between Deep forest region and Un-rooted region. This region contains only pneumatophores but it is devoid of long roots and vegetations. It faces wave attack and tidal action less than that of Un-rooted region) and Un-rooted region (It is closest to river shore and faces maximum wave attack and tidal action;it contains minimum organic carbon but maximum soil salinity and silicate concentration. This zone is totally devoid of any roots, pneumatophores and vegetations) of Sundarban mangrove forest ecosystem, India revealed an interesting explanation. Soil urease activity showed a decreasing pattern with increase in depth from the deep forest region of the Sundarban forest ecosystem. Soil urease activity was found to be more sensitive to soil temperature and pH rather than soil salinity. This ensured that soil urease along with the microbes present in the Sundarban forest ecosystem are more tolerant to fluctuation in salinity than that of temperature. Soil ammonia concentration was found to be directly governed by the soil urease activity [The regression equation is Ammonia in soil = -1.64 + 0.0402 Urease Activity (R-Sq = 62.9%, P < 0.001, n = 41)].
基金supported by the National Key Research and Development Program of China(2018YFA0404603)the Joint Research Fund in Astronomy(Nos.U1831204,U1931141 and U1631129)under cooperative agreement between the National Natural Science Foundation of China(NSFC)and the Chinese Academy of Sciences(CAS)+3 种基金the NSFC(11903009)the Yunnan Key Research and Development Program(2018IA054)the open research program of the CAS Key Laboratory of Solar Activity(KLSA201807)the major scientific research project of Guangdong regular institutions of higher learning(2017KZDXM062)
文摘Studies on the periodic variation and the phase relationship between different solar activity indicators are useful for understanding the long-term evolution of solar activity cycles.Here we report the statistical analysis of grouped solar flare(GSF) and sunspot number(SN) during the time interval from January 1965 to March 2009.We find that,(1) the significant periodicities of both GSF and SN are related to the differential rotation periodicity,the quasi-biennial oscillation(QBO),and the eleven-year Schwabe cycle(ESC),but the specific values are not absolutely identical;(2) the ESC signal of GSF lags behind that of SN with an average of 7.8 months during the considered time interval,which implies that the systematic phase delays between GSF and SN originate from the inter-solar-cycle signal.Our results may provide evidence about the storage of magnetic energy in the corona.
基金financially supported by the Robert S McNamara Fellowship Programme from the World Bank offered to Tauhidur Rahman Nurunnabi
文摘Objective: To isolate and evaluate the antimicrobial activity of the active principle(s) from the ethyl acetate(EtOAc) extract of endophytic fungus Colietotrichum gloeosporioides(C.gloeosporioides) isolated from Sonneratia apetala. Methods: Water agar technique was used to isolate the fungus, and both microscopic and molecular techniques were used for identification of the strain. Potato dextrose broth was used to grow the fungus in large-scale. Reversed-phase preparative HPLC analysis was performed to isolate the major active compound, kojic acid. The EtOAc extract and kojic acid were screened for their antimicrobial activity against two Grampositive and two Gram-negative bacteria as well as a fungal strain using the resazurin 96-well microtitre plate antimicrobial assay. Results: The fungus C. gloeosporioides was isolated from the leaves of Sonneratia apetala. Initial identification of the fugal isolate was carried out using spore characteristics observed under the microscope. Subsequently, the ITS1-5.8 S-ITS2 sequencing was employed for species-level identification of the fungus C. gloeosporioides. Five litres of liquid culture of the fungus produced approximately 610 mg of a mixture of secondary metabolites.Kojic acid(1) was isolated as the main secondary metabolite present in the fungal extract, and the structure was confirmed by 1 D, 2 D NMR and mass spectrometry. The EtOAc extract and compound 1 exhibited considerable antimicrobial activity against all tested microorganisms.Whilst the minimum inhibitory concentration(MIC) values from the EtOAc extract ranged between 2.4×10^(-4)mg/mL and 2.5 mg/mL, those of kojic acid(1) were between 0.125 mg/mL and1 mg/mL. The EtOAc extract and kojic acid(1) were most active against Pseudomonas aeruginosa(MIC = 2.4×10^(-4). mg/mL) and Micrococcus luteus(MIC = 0.125 mg/mL), respectively. Conclusions:The results revealed that the endophytic fungus C. gloeosporioides could be a good source of commercially important kojic acid, which exhibited antimicrobial properties.
文摘Populations of culturable microbes and activities of dehydrogenase & ?-D glucosidase were found maximum in surface soil and decreased with increase in depth in Sundarban mangrove environment.The maximum (13.529 X 106 C.F.U g-1 dry weight of soil) and minimum (11.547 X 106 C.F.U g-1 dry weight of soil) total microbial popu- lations in surface soil were recorded during po- st-monsoon and monsoon respectively. At 60 cm depth, the lower (6.396 X 106 C.F.U g-1 dry weight of soil) and higher (8.003 X 106 C.F.U g-1 dry weight of soil) numbers of total microbial populations were observed during monsoon and post-monsoon respectively. A decreasing trend of total microbial load, enzyme activities and nutrient status with organic carbon were found with increase in depth throughout the year. Present study revealed the relationship among depth integrated variations of physico-chemical compo- nents (viz. soil temperature, pH, moisture, orga- nic-C, .nitrogen, and available-P) and microbial populations as well as activity of dehydrogenase and ?-D glucosidase enzymes.
基金Project(20876039) supported by the National Natural Science Foundation of ChinaProject(09JJ3023) supported by Natural Science Foundation of Hunan Province, China
文摘CuO was synthesized by thermal decomposition of Cu(NO3)2·3H2O at various temperatures and characterized by powder X-ray diffractometry(XRD) as well as scanning electron microscopy(SEM).The effects of calcination temperature,category of sacrificial reagent,initial sacrificial reagent concentration,and Ag loading content on the photocatalytic activity of the as-obtained CuO sample were investigated.The results show that the as-obtained CuO exhibits high activity for photocatalysis of H2 evolution reaction(HER) in oxalic acid solution under simulated sunlight irradiation.The highest photocatalytic activity of the as-obtained CuO was achieved at the calcination temperature of 1000℃,and oxalic acid was used as the sacrificial reagent with the concentration 0.05 mol/L.H2 evolution rate is as high as 2.98 mmol/(h·g) with 2%(mass fraction) loaded Ag.The possible photocatalytic reaction mechanism on the CuO photocatalyst for HER in oxalic acid solution was also discussed.
文摘The atmospheric activity of the Sun and Sun-like stars is analyzed involving observations from the HK-project at the Mount Wilson Observatory, the California and Carnegie Planet Search Program at the Keck and Lick Observatories and the Magellan Planet Search Program at the Las Campanas Observatory. We show that for stars of E G and K spectral classes, the cyclic activity, similar to the 11-yr solar cycle, is different: it becomes more prominent in K-stars. Comparative study of Sun-like stars with different levels of chromospheric and coronal activity confirms that the Sun belongs to stars with a low level of chromospheric activity and stands apart among these stars by its minimum level of coronal radiation and minimum level of variations in photospheric flux.
基金Project(20876039) supported by the National Natural Science Foundation of ChinaProject(09JJ3023) supported by the Natural Science Foundation of Hunan Province,China
文摘Zirconia-supported CuO (CuO/ZrO2) composite photocatalysts were successfully synthesized via citric acid-assisted sol-gel technique. For comparison, CuO/ZrO2 materials were also prepared by solid state reaction and co-precipitation method. The as-prepared powders were characterized by X-ray diffractometry (XRD), transmission electron microscopy (TEM), and thermogravimetric-differential thermal analysis (TG-DTA). The photocatalytic activity of CuO/ZrO2 catalyst was investigated based on the H2 evolution from oxalic acid solution under simulated sunlight irradiation. The effects of molar ratio of CuO to ZrO2, preparation method, phase change with the calcination temperature and the durability on the photocatalytic activity of the photocatalyst were investigated in detail. It is found that the optimal activity of photocatalytic H2 evolution (2.41 mmol.h i.g-~) can be obtained when CuO/ZrO2 composite photocatalyst is synthesized by sol-gel technique and the mole ratio of CuO to ZrO2 is 40%. The activity of copper oxide supported on monoclinic ZrO2 calcined at higher temperature is much higher than that on tetragonal ZrO2 calcined at lower temperature, and the best calcination temperature is 900 ℃.
文摘The wavelet transform method for high-quality time-frequency analysis is applied to sets of observations of relative sunspot numbers and stellar chromosphere fluxes of 10 Sun-like stars. Wavelet analysis of solar data shows that in a certain interval of time there are several cycles of activity with pe- riods of duration which vary considerably from each other: from quasi-biennial cycles to lO0-yr cycles. Cyclic activity was detected in almost all Sun-like stars that we examined, even those that previously were not considered as stars with cyclic activity according to analysis using a Scargle periodogram. The durations of solar and stellar cycles significantly change during the observation period.
基金supported by the Programs for Fundamental Research of the Presidium of the Russian Academy of Sciences"Molecular-cell biology"
文摘The effect of chitosan on the development of infection caused by Tobacco mosaic virus(TMV) in leaves of Nicotiana tabacum L. cv. Samsun has been studied. It was shown that the infectivity and viral coat protein content in leaves inoculated with a mixture of TMV(2 μg/mL) and chitosan(1 mg/mL) were lower in the early period of infection(3 days after inoculation), by 63% and 66% respectively, than in leaves inoculated with TMV only. Treatment of leaves with chitosan 24 h before inoculation with TMV also caused the antiviral effects, but these were less apparent than when the virus and polysaccharide were applied simultaneously. The inhibitory effects of the agent decreased as the infection progressed. Inoculation of leaves with TMV together with chitosan considerably enhanced the activity of hydrolases(proteases, RNases) in the leaves, in comparison with leaves inoculated with TMV alone. Electron microscope assays of phosphotungstic acid(PTA)-stained suspensions from infected tobacco leaves showed that, in addition to the normal TMV particles(18 nm in diameter, 300 nm long), these suspensions contained abnormal(swollen, "thin" and "short") virions. The highest number of abnormal virions was found in suspensions from leaves inoculated with a mixture of TMV and chitosan. Immuno-electron microscopy showed that "thin" virus particles, in contrast to the particles of normal diameter, lost the ability to bind to specific antiserum. It seems that the chitosan-induced activation of hydrolases stimulates the intracellular degradation of TMV particles and hence hydrolase activation may be considered to be one of the polysaccharide-mediated cellular defense mechanisms that limit virus accumulation in cells.
基金supports of the National Key R & D Program of China (2017YFD0400402)the National Natural Science Foundation of China (31501409)
文摘Sunflower seed meal peptide as one sort of bioactive peptide has intensively application prospects. However, preparation of low salt peptide from sunflower seed meal with high efficiency remains a challenge. In this study, single and compound proteases were optimized to hydrolyze protein. Results showed that hydrolysis at pH 7.0 by proteases resulted in ash content in the range of 5.66%-7.37% and small peptides. Among all hydrolysis processes, sequential hydrolysis of Alcalase with Flavourzyme and Alcalase with Protamex showed higher nitrogen recovery ratio (67.66% and 66.49%, respectively). Furthermore, biological activities of peptides were investigated by testing their ABTS (2,2-azinobis (3-ethylben-zothiazoline-6-sulfonic acid) diammonium salt) radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazil) radical scavenging activity and angiotensin converting enzyme (ACE) inhibitory activity. Peptide hydrolyzed by Alcalase with Papain presented the highest antioxidant activity, followed by Alcalase with Protamex, with ABTS scavenging rate as 63.01% and 31.75%, and DPPH scavenging rate as 56.04% and 28.06%, respectively. Synchronously, peptide hydrolyzed by Alcalase with Protamex and Alcalase with Alcalase had the highest ACE inhibitory activity (56.74%, 56.76%). In conclusion, hydrolysis by proteases Alcalase with Protamex at pH 7.0 was the most effective method for the preparation of low salt peptide from sunflower seed meal, which could be an alternative for anti-oxidants and anti-vasoconstrictor.
基金Supported by the National Natural Science Foundation of China
文摘Two primary solar-activity indicators- sunspot numbers (SNs) and sunspot areas (SAs) in the time interval from November 1874 to December 2012 - are used to determine the chaotic and fractal properties of solar activity. The results show that (1) the long-term solar activity is governed by a low-dimensional chaotic strange attractor, and its fractal motion shows a long-term persistence on large scales; (2) both the fractal dimension and maximal Lyapunov exponent of SAs are larger than those of SNs, implying that the dynamical system of SAs is more chaotic and complex than SNs; (3) the predictions of solar activity should only be done for short- to mid-term behaviors due to its intrinsic complexity; moreover, the predictability time of SAs is obviously smaller than that of SNs and previous results.
文摘Baculoviruses are effective biocontrol agents except of their short persistence under sunlight conditions. Four promising additives containing different groups of antioxidants were tested on cotton plant foliage. Spodoptera littoralis test insect and its nuclepolyhedrovirus (SpliNPV) are the standard material used in the investigation. Results are based on leaf-bioassays, to test Original Activity Remaining (OAR) and Lethal Infectivity Time to 50% (LIT50)of tested population of the virus after exposure to natural sunlight. The results showed that cacao additive at 10%, sustained 50% of virus activity for five days post application (113.11 hours) and three days and a half (83.33 hours) at 5% concentration. The virus alone treatment sustained 50% of its activity for only 24.07 hours. The obtained results suggested the possibility of prolonging the virus activity on plant foliage under field applications.
文摘The HDPFF (heavy-disaster-period of forest fire) takes up 1 / 4-1 / 3 of all observation years, but the loss takes up 80-90% of all. The author studied the relations between forest fire activity in Heilongiiang Province from 1950 to 1989 and activity of sunspot, SSTA (sea surface temperature abnormality) of the North Pacific Ocean. The study discovered that : (1 )there was a negative correlation between forest fire condition in Heilongjiang Province and annual average of sunspot relative numbers, furthermore, the heavy-disaster-period was prone to occur in valley year and the next year; (2) SSTA in the North Pacific Ocean markedly influenced the forest fire activity and the level of its conditions in Heilongjiang province.
基金Supported by the National Natural Science Foundation of China
文摘We present a study of seven large solar proton events in the current solar cycle 24(from 2009 January up to the current date). They were recorded by the GOES spacecraft with the highest proton fluxes being over 200 pfu for energies 〉10 Me V. In situ particle measurements show that:(1) The profiles of the proton fluxes are highly dependent on the locations of their solar sources, namely flares or coronal mass ejections(CMEs), which confirms the "heliolongitude rules" associated with solar energetic particle fluxes;(2) The solar particle release(SPR) times fall in the decay phase of the flare emission, and are in accordance with the times when the CMEs travel to an average height of 7.9 solar radii; and(3) The time differences between the SPR and the flare peak are also dependent on the locations of the solar active regions. The results tend to support the scenario of proton acceleration by the CME-driven shock,even though there exists a possibility of particle acceleration at the flare site, with subsequent perpendicular diffusion of accelerated particles in the interplanetary magnetic field. We derive the integral time-of-maximum spectra of solar protons in two forms: a single power-law distribution and a power law roll-over with an exponential tail. It is found that the unique ground level enhancement that occurred in the event on 2012 May 17 displays the hardest spectrum and the largest roll-over energy which may explain why this event could extend to relativistic energies.
文摘In this paper we present an approach for forecasting the imminent regional seismic activity by using geomagnetic data and Earth tide data. The time periods of seismic activity are the time periods around the Sun-Moon extreme of the diurnal average value of the tide vector module. For analyzing the geomagnetic data behaviour we use diurnal standard deviation of geomagnetic vector components F (North, East, Down) for calculating the time variance GeomagSignal. The Sun storm influence is avoided by using data for daily A-indexes (published by NOAA). The precursor signal for forecasting the incoming regional seismic activity is a simple function of the present and previous day GeomagSignal and A-indexes values. The reliability of the geomagnetic “when, regional” precursor is demonstrated by using statistical analysis of day difference between the times of “predicted” and occurred earthquakes. The base of the analysis is a natural hypothesis that the “predicted” earthquake is the one whose surface energy density in the monitoring point is bigger than the energy densities of all occurred earthquakes in the same period and region. The reliability of the approach was tested using the INTERMAGNET stations data located in Bulgaria, Panagurishte, PAG (Jan 1, 2008-Jan 29, 2014), Romania, Surlari, SUA (Jan 1, 2008-Jan 27, 2014), Italy, L’Aquila, AQU (Jan 1, 2008-May 30, 2013) in the time of EU IRSES BlackSeaHazNet (2011-2014) project. The steps of program for solving the “when, where and how” earthquake prediction problem are shortly described.