Apple (<i><span style="font-family:Verdana;">Malus </span></i><span style="font-family:Verdana;">× </span><i><span style="font-family:Verdana;...Apple (<i><span style="font-family:Verdana;">Malus </span></i><span style="font-family:Verdana;">× </span><i><span style="font-family:Verdana;">domestica </span></i><span style="font-family:Verdana;">Borkh.)</span><b><i> </i></b><span style="font-family:Verdana;">is a perennial woody plant that often suffers from various biological stresses. Many harmful pathogens can infect apple trees and lead to reduced production. We comprehensively identified the </span><i><span style="font-family:Verdana;">WRKY</span></i><span style="font-family:Verdana;"> genes in the apple genome and analyzed their expression in response to several biological stressors, including </span><i><span style="font-family:Verdana;">Alternaria alternata</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Pythium ultimum</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Botryosphaeria dothidea</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Erwinia amylovora</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Penicillium expansum</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Gymnosporangium yamadae</span></i><span style="font-family:Verdana;">, and Apple replant disease. There were 113 </span><i><span style="font-family:Verdana;">MdWRKYs</span></i><span style="font-family:Verdana;"> identified in the apple genome. Twenty-two </span><i><span style="font-family:Verdana;">MdWRKYs</span></i><span style="font-family:Verdana;"> were differentially expressed in response to at least five pathogens. Promoter sequence analysis showed that these genes carried many defense- and stress-responsive elements, such as MeJA-response elements, salicylic acid-response elements, and W-box elements, in their promoters. Transient expression assays showed that </span><i><span style="font-family:Verdana;">MdWRKY</span></i><span style="font-family:Verdana;">40</span><i><span style="font-family:Verdana;">a</span></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">MdWRKY</span></i><span style="font-family:Verdana;">54</span><i><span style="font-family:Verdana;">h</span></i><span style="font-family:Verdana;"> played negative roles in defense against </span><i><span style="font-family:Verdana;">B. dothidea</span></i><span style="font-family:Verdana;"> infection. </span><i><span style="font-family:Verdana;">WRKY</span></i><span style="font-family:Verdana;">40 and </span><i><span style="font-family:Verdana;">WRKY</span></i><span style="font-family:Verdana;">60 and the </span><i><span style="font-family:Verdana;">MdWKRY</span></i><span style="font-family:Verdana;">33</span><i><span style="font-family:Verdana;">s</span></i><span style="font-family:Verdana;"> might play important roles in responding to pathogens and are conserved in some plants. These differentially expressed </span><i><span style="font-family:Verdana;">MdWRKYs</span></i><span style="font-family:Verdana;"> might play key roles in the apple response to multiple pathogens.</span>展开更多
AIM: To evaluate the clinical outcomes of 240-wk treatment with entecavir(0.5 mg) in Chinese nucleosidenaive patients with cirrhosis.METHODS: A total of 204 nucleoside-naive patients with compensated(n = 96) or decomp...AIM: To evaluate the clinical outcomes of 240-wk treatment with entecavir(0.5 mg) in Chinese nucleosidenaive patients with cirrhosis.METHODS: A total of 204 nucleoside-naive patients with compensated(n = 96) or decompensated(n = 108) hepatitis B virus(HBV)-induced cirrhosis at the Department of Gastroenterology of the China-Japan Union Hospital(Jilin University, Changchun, China) who were treated with entecavir(0.5 mg) for 240 wk were enrolled in this study. Liver biopsy samples obtained from 38 patients prior to treatment(baseline) and at week 240 were evaluated by different independent histopathologists. Efficacy assessments included the proportions of patients who achieved an HBV DNA level < 500 copies/m L, the association of interleukin-28 B genetic variation with antivirus therapy, clinical outcomes, and histologic improvement. Changes in liver disease severity were analyzed, and liver histologic evaluation was performed in 38 patients with paired biopsies. Student t tests were used to compare the means of continuous variables between the groups, and the proportions of patients who achieved the endpoints were compared using the χ2 test.RESULTS: At week 240, 87.5% of the patients with compensated cirrhosis and 92.6% of the patients with decompensated cirrhosis achieved a HBV DNA level < 500 copies/m L. Three patients had genotypic entecavir resistance within the 240-wk period. No significant association was observed between virologic response and interleukin-28 genotype(CT, 88.2% vs CC, 90.6%). The proportion of patients with Child-Pughclass A disease was significantly increased at week 240(68%) from the baseline(47%; P < 0.01). The proportion of patients with Child-Pugh class B disease was significantly decreased at week 240(25%) from the baseline(39%; P = 0.02). In the patients with paired liver biopsies, the mean reduction in the Knodell necroinflammatory score from the baseline was 3.58 ± 1.03 points(7.11 ± 1.80 vs 3.53 ± 1.35, P < 0.01). The mean reduction in Ishak fibrosis score from the baseline was 1.26 ± 0.64 points(5.58 ± 0.50 vs 4.32 ± 0.81, P < 0.01).CONCLUSION: Entecavir is an effective treatment option for patients with HBV-related compensated or decompensated cirrhosis that can result in sustained virologic suppression and histologic improvement.展开更多
AIM To investigate the utility of 1H magneticresonance spectroscopy (1H MRS) as a noninvasivetest for steatosis in patients infected with hepatitis Cvirus.METHODS: Ninety patients with chronic hepatitisC and pathol...AIM To investigate the utility of 1H magneticresonance spectroscopy (1H MRS) as a noninvasivetest for steatosis in patients infected with hepatitis Cvirus.METHODS: Ninety patients with chronic hepatitisC and pathology data underwent 3.0T 1H MRS, andthe results of MRS and pathological analysis werecompared.RESULTS: This group of patients included 26 peoplewith mild fatty liver (28.89%), 16 people withmoderate fatty liver (17.78%), 18 people with severefatty liver (20.0%), and 30 people without fatty liver(33.33%). The water peak was near 4.7 parts permillion (ppm), and the lipid peak was near 1.3 ppm.Analysis of variance revealed that differences in thelipid peak, the area under the lipid peak, ratio of thelipid peak to the water peak, and ratio of the areaunder the lipid peak to the area under the waterpeak were statistically significant among the groups.Specifically, as the severity of fatty liver increased, thevalue of each index increased correspondingly. In thepairwise comparisons, the mean lipid peak, area underthe lipid peak, ratio of the lipid peak to the waterpeak, and ratio of the area under the lipid peak to thearea under the water peak were significantly differentbetween the no fatty liver and moderate fatty liver groups, whereas no differences were noted betweenthe severe fatty liver group and the mild or moderatefatty liver group. Area under the ROC curve (AUC) ofarea ratio in lipid and water and ratio in lipid and waterin the no fatty liver group to mild fatty liver group, mildfatty liver group to moderate fatty liver group, andmoderate fatty liver disease group to severe fatty livergroup, were 0.705, 0.900, and 0.975, respectively.CONCLUSION: 1H MRS is a noninvasive techniquethat can be used to provide information on the effectof liver steatosis on hepatic metabolic processes. Thisstudy indicates that the 1H MRS can be used as anindicator of steatosis in patients with chronic hepatitis C.展开更多
This paper proposes a novel Ka band non-orthogonal multiple access(NOMA)uplink relay system for Lunar farside exploration,where a satellite relay node with the help of NOMA scheme,amplifies and forwards the signal fro...This paper proposes a novel Ka band non-orthogonal multiple access(NOMA)uplink relay system for Lunar farside exploration,where a satellite relay node with the help of NOMA scheme,amplifies and forwards the signal from the Earth Base Station(EBS)to a Lunar rover and a lander.We assume that the signal undergoes shadowed-Rician fading for the source-relay link and Rayleigh fading for the relay-destination link.Then,the analytical expressions for the outage probability(OP)and ergodic capacity are derived for the satellite relay node equipped with single and multiple antennas,respectively.In addition,we obtain the optimal power allocation coefficients by maximizing the sum ergodic capacity of the system,and we calculate the power consumption of the NOMA uplink relay system to achieve the same OP performance of OMA system and provide some useful guides for the design of the Earth-to-Lunar communication system.Simulations are provided to confirm the reliability of our analytical results and show the impact of various parameters on the system performance.展开更多
Drought stress is one of the major environmental obstacles that limit the production and development of apples(Malus domestica Borkh.).The role of melatonin is well known in the protection of plants under environmenta...Drought stress is one of the major environmental obstacles that limit the production and development of apples(Malus domestica Borkh.).The role of melatonin is well known in the protection of plants under environmental stresses.In this study,we investigated the effect of melatonin on apple rootstock M.hupehensis Rehd under drought stress.The results showed that drought inhibited the growth of M.hupehensis and dramatically reduced root surface area,root volume,the number of tips and forks,and root diameter.Drought-induced growth inhibition was significantly decreased by adding melatonin.Net photosynthetic rate(Pn),intercellular CO_(2)concentration(Ci),stomatal conductance(Gs),transpiration rate(Tr),were markedly reduced under drought stress.However,the application of melatonin could mitigate the damage to the photosynthetic apparatus and increase the quantum yield of PSII photochemistry.Additionally,generation of hydrogen peroxide(H_(2)O_(2))and superoxide radicals(O_(2)^(•–))sharply increased in apple leaves after 4 days under drought stress,and the accumulation of electrolyte leakage(EL)represented oxidative stress,while by applying melatonin under drought stress,the generation of O_(2)^(•–)and H_(2)O_(2)were significantly reduced and protected the membrane from drought damages.These results suggest that the adverse effects of drought can be minimized by applying melatonin to apples.展开更多
BACKGROUND Colorectal cancer(CRC)is one of the most common malignant tumors of the digestive tract.Lymphatic metastases of this tumor are mostly confined to the regional lymph nodes,and distant supraclavicular lymph n...BACKGROUND Colorectal cancer(CRC)is one of the most common malignant tumors of the digestive tract.Lymphatic metastases of this tumor are mostly confined to the regional lymph nodes,and distant supraclavicular lymph node metastases are very rare.CASE SUMMARY In this report,we describe a patient with sigmoid carcinoma and isolated synchronous supraclavicular lymph node metastases.A 56-year-old male presented with a left cervical mass that was confirmed as a lymph node metastasis from sigmoid cancer by several auxiliary examinations.After 6 cycles of chemotherapy with the 5-fluorouracil,leucovorin and oxaliplatin+cetuximab regimen,the sigmoid colon tumor and Virchow’s lymph node metastasis were significantly smaller than before treatment,and no new metastatic sites were observed.Considering the effects of chemotherapy on quality of life,resection of the primary tumor was performed followed by 4 cycles of chemotherapy with the original chemotherapy regimen.Virchow’s lymph node dissection was selected by mutual consultation between the patient and us.After the second surgery,the patient received capecitabine and cetuximab chemotherapy and did not experience recurrence or metastasis during follow-up.CONCLUSION In conclusion,supraclavicular lymph node metastasis without any other solid organ metastasis is a potential metastatic pathway for CRC.In addition,after resection of the primary lesion,postoperative chemotherapy combined with supraclavicular lymph node dissection is feasible for the treatment of patients with CRC and isolated synchronous Virchow’s lymph node metastases.展开更多
Apple is one of the most important fruit trees in temperate zones, and is cultivated widely throughout the world. Drought stress affects the normal growth of apple tree, and further affects fruit yield and quality. Th...Apple is one of the most important fruit trees in temperate zones, and is cultivated widely throughout the world. Drought stress affects the normal growth of apple tree, and further affects fruit yield and quality. The present study examined the effects of drought on photosynthesis and water use efficiency (WUE) of two apple cultivars (Honeycrisp and Yanfu 3) that differ in drought tolerance. The results showed that the photosynthetic rate decreased in response to drought stress for both cultivars, with significant differences in intensity. Values for net photosynthetic rate (Pn) in stressed Yanfu 3 remained significantly lower than in the controls, while, for Honeycrisp, only a slight drop in photosynthesis. Similarly, stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) were markedly reduced in Yanfu 3 under drought stress. However, Honeycrisp showed only minor changes. Under drought stress, the contents of Chl a, Chl b and Chl t in Yanfu 3 were all decreased significantly compared with the control. However, little difference in Honeycrisp was noted between stressed plants and controls. Values for WUE in stressed Yanfu 3 remained higher than in the controls from day 3 until the end of the experiment, while no significant difference was observed in Honeycrisp. Furthermore, Honeycrisp also exhibited superior physiological traits, as indicated by its anatomical and morphological characteristics. Therefore, we conclude that the superior drought tolerance of Honeycrisp was due to its anatomical and morphological characteristics, which possibly contributed to the maintenance of higher photosynthetic capacity than Yanfu 3.展开更多
Mollisols are rich in organic matter,which makes them suitable for cultivation and for enhancing global food security.Mollisols are experiencing severe soil erosion due to overfarming and a lack of mainte-nance.Thus,s...Mollisols are rich in organic matter,which makes them suitable for cultivation and for enhancing global food security.Mollisols are experiencing severe soil erosion due to overfarming and a lack of mainte-nance.Thus,suitable soil and water conservation measures(SWCMs)are needed to protect Mollisols.However,how SWCMs respond to changes in slope gradient and rainfall and their effective application area remain ambiguous.Using a long-term field observation dataset,meta-analysis,and statistical test methods,we reveal the typical erosion reduction effect of SWCMs and their responses to changes in slope gradient and rainfall.Next,we calculated a coupling factor,P.S,by slope gradient and rainfall in flood season to determine the effective SWCMs application threshold.Compared with bare land,no-tillage(NT),contour ridge tillage(CT),ridge hedgerows(RH),and terraced fields(TF)had an average erosion reduction coefficient of 91.5%.There was a significant exponential increase in the correlation between P.S and the soil erosion amount in plots with typical measures.According to this correlation and soil loss tolerance(200 t/km^(2)),the upper limits of PS(NT:564 mm;CT:885 mm;RH:1135 mm)were determined and utilized to determine the effective application areas(NT:311.40103 km^(2);CT:320.86103 km^(2);RH:323.72103 km^(2))at the plot scale.In wet years,the applicable area of SWCMs declined toward the low-elevation foothills and flat terrain.All the results are applicable when slope length within 20 m.These results provide a basis for the precise allocation of SWCMs in Mollisols area and promote the scientific utilization of Mollisols resources.展开更多
Excellent impedance matching and high conduction loss are important factors for the preparation of high-performance electromagnetic wave(EMW)absorbing materials,but these two properties are of-ten contradictory.In thi...Excellent impedance matching and high conduction loss are important factors for the preparation of high-performance electromagnetic wave(EMW)absorbing materials,but these two properties are of-ten contradictory.In this work,three absorbers with unique hollow structures,H-Ag/CuO@CuS,H-O-Ag/CuO@CuS,and H-P-Ag/CuO@CuS,are designed and synthesized by adopting hollow CuO@CuS with double shell as carrier and silver nitrate as the structural regulator.The more voids coming from hol-low structures,window-opened structures,and stacked pores improve the impedance matching of these absorbers,and the introduction of elemental Ag effectively regulates the conduction loss.Therefore,a balance between impedance matching and conduction loss is achieved to improve the reflection loss(RL)value and broadens the absorbing band of the absorbers.In comparison to H-Ag/CuO@CuS and H-O-Ag/CuO@CuS(hollow structure with open window)in which elemental Ag is uniformly dispersed in the CuO layer,H-P-Ag/CuO@CuS exhibits more excellent EMW absorption performance due to more voids and an optimized conductive network arising from Ag/CuO pieces distributed between the hol-low Ag/CuO@CuS particles and Ag distributed in the CuS layer.When the thickness is 2.3 mm,H-P-Ag/CuO@CuS provides an ultra-wide electromagnetic absorption band of 8.56 GHz(9.44-18 GHz),in which the RL<-10 dB and the minimum reflection loss of-41 dB.展开更多
The tumor suppressor p53 protein is either lost or mutated in about half of all human cancers.Loss of p53 function is well known to influence cell spreading,migration and invasion.While expression of mutant p53 is not...The tumor suppressor p53 protein is either lost or mutated in about half of all human cancers.Loss of p53 function is well known to influence cell spreading,migration and invasion.While expression of mutant p53 is not equivalent to p53 loss,mutant p53 can acquire new functions to drive cell spreading and migration via different mechanisms.In our study,we found that mutant p53 significantly increased cell spreading and migration when comparing with p53-null cells.RNA-Seq analysis suggested that Rho GTPase activating protein 44(ARHGAP44) is a new target of mutant p53,which suppressed AKHGAP44 transcription.ARHGAP44 has GAP activity and catalyze GTP hydrolysis on Cdc42.Higher level of GTP-Cdc42 was correlated with increase expression of mutant p53 and reduced ARHGAP44.Importantly,wt-ARHGAP44 but not mutant ARHGAP44(R291A) suppressed mutant p53 mediated cell spreading and migration.Bioinformatics analysis indicated lower expression of ARHGAP44 in lung carcinoma compared with normal tissues,which was verified by RT-qPCR using specimens from patients.More interestingly,ARHGAP44 mRNA level was lower in tumors with mutant p53 than those with normal p53.Collectively,our results disclose a new mechanism by which mutant p53 stimulates cell spreading and migration.展开更多
Periodontitis is an inflammatory disease initiated by bacterial infection,developed by excessive immune response,and aggravated by high level of reactive oxygen species(ROS).Hence,herein,a versatile metal-organic fram...Periodontitis is an inflammatory disease initiated by bacterial infection,developed by excessive immune response,and aggravated by high level of reactive oxygen species(ROS).Hence,herein,a versatile metal-organic framework(MOF)-based nanoplatform is prepared using mesoporous Prussian blue(MPB)nanoparticles to load BA,denoted as MPB-BA.The established MPB-BA nanoplatform serves as a shelter and reservoir for vulnerable immunomodulatory drug BA,which possesses antioxidant,anti-inflammatory and anti-bacterial effects.Thus,MPB-BA can exert its antioxidant,anti-inflammatory functions through scavenging intracellular ROS to switch macrophages from M1 to M2 phenotype so as to relieve inflammation.The underlying molecular mechanism lies in the upregulation of phosphorylated nuclear factor erythroid 2-related factor 2(Nrf2)to scavenge ROS and subsequently inhibit the nuclear factor kappa-B(NF-κB)signal pathway.Moreover,MPB-BA also exhibited efficient photothermal antibacterial activity against periodontal pathogens under near-infrared(NIR)light irradiation.In vivo RNA sequencing results revealed the high involvement of both antioxidant and anti-inflammatory pathways after MPB-BA application.Meanwhile,micro-CT and immunohistochemical staining of p-Nrf2 and p-P65 further confirmed the superior therapeutic effects of MPB-BA than minocycline hydrochloride.This work may provide an insight into the treatment of periodontitis by regulating Nrf2/NF-κB signaling pathway through photothermal bioplatform-assisted immunotherapy.展开更多
A study on the removal of Co(Ⅱ) from aqueous solutions by water treatment residuals(WTR)was conducted in batch conditions. The sorption process of Co(Ⅱ) followed pseudosecondorder kinetics, with 30 hr required to re...A study on the removal of Co(Ⅱ) from aqueous solutions by water treatment residuals(WTR)was conducted in batch conditions. The sorption process of Co(Ⅱ) followed pseudosecondorder kinetics, with 30 hr required to reach equilibrium. Using the Langmuir adsorption isotherm model, a relatively high maximum sorption capacity of 17.31 mg/g Co(Ⅱ) was determined. The adsorption of Co(Ⅱ) was dependent on pH values and was affected by the ionic strength. Results show that Co(Ⅱ) adsorption was a spontaneous endothermic process and was favorable at high temperature. Most of the adsorbed Co(Ⅱ) stayed on the WTR permanently, whereas only small amounts of adsorbed Co(Ⅱ) were desorbed. The shifting of peaks in FT-IR spectra indicated that Co(Ⅱ) interacted with the WTR surface through strong covalent bond formation with Fe(Al)–O functional groups. It was concluded that WTR can be a suitable material from which to develop an efficient adsorbent for the removal of Co(Ⅱ) from wastewater.展开更多
Detailed survey and inspection of the structure of the lecture hall of the Anyuan Miners’Club were conducted during a restoration project.Nondestructive inspection measures were used to assess the physical and mechan...Detailed survey and inspection of the structure of the lecture hall of the Anyuan Miners’Club were conducted during a restoration project.Nondestructive inspection measures were used to assess the physical and mechanical conditions of the structure.The brick and wood structures of the building were tested,the overall bearing capacity was calculated,and a safety appraisal was conducted in accordance with the codes and standards of the existing building.Inspection results provide architects and construction engineers with reliable data to develop a preservation plan and ensure the safety of the heritage building.展开更多
To screen novel antifungal agents targeting the succinate dehydrogenase(SDH),a series of pyrazole-4-carbohydrazides were rationally designed,synthesized,and characterized under the guidance of the structures of succin...To screen novel antifungal agents targeting the succinate dehydrogenase(SDH),a series of pyrazole-4-carbohydrazides were rationally designed,synthesized,and characterized under the guidance of the structures of succinate dehydrogenase inhibitors(SDHIs).Bioassay results in vitro indicated that most of the target compounds exhibited excellent activity against Rhizoctonia solani(R.solani),Fusarium graminearum(F.graminearum),Botrytis cinerea(B.cinerea)and Colletotrichum capsica(C.cinerea).Compounds 7d,7l,7t and 7x were identified as the most promoting candidates,and their anti-F.graminearum EC50 values were as low as 0.56,0.47,0.46 and 0.49μg/mL,respectively,presenting the similar antifungal activity as that of the commonly used fungicide carbendazim(0.43μg/mL).The 3D-QSAR models were built for a systematic structure-activity relationship profile to explore more potent pyrazole-4-carbohydrazides as novel fungicides.Molecular docking of 7d,7l and 7r with SDH was performed to reveal the binding modes in active pocket and analyze the interactions between the molecules and the SDH protein.展开更多
Background:There is limited evidence of the effects of local anesthesia(LA)on outcomes of non-surgical periodontal treatment(NSPT),in particular among the Chinese.This retrospective cohort study aimed to evaluate the ...Background:There is limited evidence of the effects of local anesthesia(LA)on outcomes of non-surgical periodontal treatment(NSPT),in particular among the Chinese.This retrospective cohort study aimed to evaluate the effects of LA on short-term treatment outcomes of NSPT and to determine under what circumstances LA should be prescribed to improve these outcomes.Methods:Data from periodontal examinations of 3980 patients were used.The data were from 3-month re-evaluation records of an electronic periodontal charting record system in the Department of Periodontology of Peking University School and Hospital of Stomatology from June 2008 to January 2015.Descriptive analyses included changes in probing depth(PD)and the Mazza bleeding index(BI).Two-level(patient and tooth)logistic regression models and three-level(patient,tooth,and site)linear regression models were constructed to analyze the influence of LA on PD for all teeth/sites and teeth/sites with an initial PD≥5 mm.Decreases in PD and BI at sites under LA using the initial PD were also compared.Results:A significantly higher mean decrease in PD after NSPT was found in the LA group than in the no local anesthesia(NLA)group(0.98 vs.0.54 mm,t=24.12,P<0.001).A significantly higher probability of decreases was found in the LA group in BI(percentages of teeth with BI>1 and BI>2)for all teeth(16.7%vs.13.8%,t=3.75,P<0.001;34.7%vs.28.1%,t=6.73,P<0.001)and PD for teeth with PD≥5mm(32.3%vs.17.3%,t=28.48,P<0.001).The difference in PD between the LA and NLA groups increased as the initial PD increased.The difference between the two groups was 0.12 to 0.22 mm for sites with a baseline PD<7 mm;however,it increased to 0.41 to 1.37 mm for sites with a baseline PD≥7 mm.Conclusions:LA improved the decrease in PD after NSPT.Root debridement at sites with initial PD≥7 mm should be performed under routine LA.展开更多
The increasing demands in terms of high data rate and quality of services over the hybrid satellite-terrestrial relay networks(HSTRN)have pushed for the development of millimeter-wave(mmWave)band high-throughput satel...The increasing demands in terms of high data rate and quality of services over the hybrid satellite-terrestrial relay networks(HSTRN)have pushed for the development of millimeter-wave(mmWave)band high-throughput satellites(HTS)with multibeams.The next generation of mmWave multibeam HTS communication systems(HTSCS)is viewed as the backbone network to enhance the throughput of the HSTRN.The article first investigates the basic backbone topology architecture of HTSCS,and an M-state Markov channel for the Ka/Q/V band mmWave systems is reviewed.Then,we propose a long-term optimal power allocation scheme over two in-dependent and identical spot beams based on the partially observable Markov decision process(POMDP),which can partly mitigate the negative effects of severe weather conditions.The key conditions for selecting the optimal power allocation action in the multibeam HTSCS are given.Simulation results show that our POMDP-based power allocation scheme can enhance the long-term throughput of the HTSCS.展开更多
文摘Apple (<i><span style="font-family:Verdana;">Malus </span></i><span style="font-family:Verdana;">× </span><i><span style="font-family:Verdana;">domestica </span></i><span style="font-family:Verdana;">Borkh.)</span><b><i> </i></b><span style="font-family:Verdana;">is a perennial woody plant that often suffers from various biological stresses. Many harmful pathogens can infect apple trees and lead to reduced production. We comprehensively identified the </span><i><span style="font-family:Verdana;">WRKY</span></i><span style="font-family:Verdana;"> genes in the apple genome and analyzed their expression in response to several biological stressors, including </span><i><span style="font-family:Verdana;">Alternaria alternata</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Pythium ultimum</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Botryosphaeria dothidea</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Erwinia amylovora</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Penicillium expansum</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Gymnosporangium yamadae</span></i><span style="font-family:Verdana;">, and Apple replant disease. There were 113 </span><i><span style="font-family:Verdana;">MdWRKYs</span></i><span style="font-family:Verdana;"> identified in the apple genome. Twenty-two </span><i><span style="font-family:Verdana;">MdWRKYs</span></i><span style="font-family:Verdana;"> were differentially expressed in response to at least five pathogens. Promoter sequence analysis showed that these genes carried many defense- and stress-responsive elements, such as MeJA-response elements, salicylic acid-response elements, and W-box elements, in their promoters. Transient expression assays showed that </span><i><span style="font-family:Verdana;">MdWRKY</span></i><span style="font-family:Verdana;">40</span><i><span style="font-family:Verdana;">a</span></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">MdWRKY</span></i><span style="font-family:Verdana;">54</span><i><span style="font-family:Verdana;">h</span></i><span style="font-family:Verdana;"> played negative roles in defense against </span><i><span style="font-family:Verdana;">B. dothidea</span></i><span style="font-family:Verdana;"> infection. </span><i><span style="font-family:Verdana;">WRKY</span></i><span style="font-family:Verdana;">40 and </span><i><span style="font-family:Verdana;">WRKY</span></i><span style="font-family:Verdana;">60 and the </span><i><span style="font-family:Verdana;">MdWKRY</span></i><span style="font-family:Verdana;">33</span><i><span style="font-family:Verdana;">s</span></i><span style="font-family:Verdana;"> might play important roles in responding to pathogens and are conserved in some plants. These differentially expressed </span><i><span style="font-family:Verdana;">MdWRKYs</span></i><span style="font-family:Verdana;"> might play key roles in the apple response to multiple pathogens.</span>
基金Supported by Grant from the Youth scientific research fund,No.2013207059
文摘AIM: To evaluate the clinical outcomes of 240-wk treatment with entecavir(0.5 mg) in Chinese nucleosidenaive patients with cirrhosis.METHODS: A total of 204 nucleoside-naive patients with compensated(n = 96) or decompensated(n = 108) hepatitis B virus(HBV)-induced cirrhosis at the Department of Gastroenterology of the China-Japan Union Hospital(Jilin University, Changchun, China) who were treated with entecavir(0.5 mg) for 240 wk were enrolled in this study. Liver biopsy samples obtained from 38 patients prior to treatment(baseline) and at week 240 were evaluated by different independent histopathologists. Efficacy assessments included the proportions of patients who achieved an HBV DNA level < 500 copies/m L, the association of interleukin-28 B genetic variation with antivirus therapy, clinical outcomes, and histologic improvement. Changes in liver disease severity were analyzed, and liver histologic evaluation was performed in 38 patients with paired biopsies. Student t tests were used to compare the means of continuous variables between the groups, and the proportions of patients who achieved the endpoints were compared using the χ2 test.RESULTS: At week 240, 87.5% of the patients with compensated cirrhosis and 92.6% of the patients with decompensated cirrhosis achieved a HBV DNA level < 500 copies/m L. Three patients had genotypic entecavir resistance within the 240-wk period. No significant association was observed between virologic response and interleukin-28 genotype(CT, 88.2% vs CC, 90.6%). The proportion of patients with Child-Pughclass A disease was significantly increased at week 240(68%) from the baseline(47%; P < 0.01). The proportion of patients with Child-Pugh class B disease was significantly decreased at week 240(25%) from the baseline(39%; P = 0.02). In the patients with paired liver biopsies, the mean reduction in the Knodell necroinflammatory score from the baseline was 3.58 ± 1.03 points(7.11 ± 1.80 vs 3.53 ± 1.35, P < 0.01). The mean reduction in Ishak fibrosis score from the baseline was 1.26 ± 0.64 points(5.58 ± 0.50 vs 4.32 ± 0.81, P < 0.01).CONCLUSION: Entecavir is an effective treatment option for patients with HBV-related compensated or decompensated cirrhosis that can result in sustained virologic suppression and histologic improvement.
基金Supported by National Natural Science Foundation of China,No.30970415
文摘AIM To investigate the utility of 1H magneticresonance spectroscopy (1H MRS) as a noninvasivetest for steatosis in patients infected with hepatitis Cvirus.METHODS: Ninety patients with chronic hepatitisC and pathology data underwent 3.0T 1H MRS, andthe results of MRS and pathological analysis werecompared.RESULTS: This group of patients included 26 peoplewith mild fatty liver (28.89%), 16 people withmoderate fatty liver (17.78%), 18 people with severefatty liver (20.0%), and 30 people without fatty liver(33.33%). The water peak was near 4.7 parts permillion (ppm), and the lipid peak was near 1.3 ppm.Analysis of variance revealed that differences in thelipid peak, the area under the lipid peak, ratio of thelipid peak to the water peak, and ratio of the areaunder the lipid peak to the area under the waterpeak were statistically significant among the groups.Specifically, as the severity of fatty liver increased, thevalue of each index increased correspondingly. In thepairwise comparisons, the mean lipid peak, area underthe lipid peak, ratio of the lipid peak to the waterpeak, and ratio of the area under the lipid peak to thearea under the water peak were significantly differentbetween the no fatty liver and moderate fatty liver groups, whereas no differences were noted betweenthe severe fatty liver group and the mild or moderatefatty liver group. Area under the ROC curve (AUC) ofarea ratio in lipid and water and ratio in lipid and waterin the no fatty liver group to mild fatty liver group, mildfatty liver group to moderate fatty liver group, andmoderate fatty liver disease group to severe fatty livergroup, were 0.705, 0.900, and 0.975, respectively.CONCLUSION: 1H MRS is a noninvasive techniquethat can be used to provide information on the effectof liver steatosis on hepatic metabolic processes. Thisstudy indicates that the 1H MRS can be used as anindicator of steatosis in patients with chronic hepatitis C.
基金supported in part by the National Natural Sciences Foundation of China(NSFC)under Grant 61771158,Grant 61871147,Grant 61831008,Grant 91638204,and Grant 61525103in part by the Shenzhen Basic Research Program under Grant J CYJ20170811154309920,Grant JCYJ20170811160142808,and Grant ZDSYS201707280903305+2 种基金in part by the Guangdong Science and Technology Planning Project under Grant 2018B030322004in part by the Natural Science Foundation of Guangdong Province under Grant 2020A1515010505in part by the project The Verification Platform of Multi-tier Coverage Communication Network for Oceans under Grant LZC0020。
文摘This paper proposes a novel Ka band non-orthogonal multiple access(NOMA)uplink relay system for Lunar farside exploration,where a satellite relay node with the help of NOMA scheme,amplifies and forwards the signal from the Earth Base Station(EBS)to a Lunar rover and a lander.We assume that the signal undergoes shadowed-Rician fading for the source-relay link and Rayleigh fading for the relay-destination link.Then,the analytical expressions for the outage probability(OP)and ergodic capacity are derived for the satellite relay node equipped with single and multiple antennas,respectively.In addition,we obtain the optimal power allocation coefficients by maximizing the sum ergodic capacity of the system,and we calculate the power consumption of the NOMA uplink relay system to achieve the same OP performance of OMA system and provide some useful guides for the design of the Earth-to-Lunar communication system.Simulations are provided to confirm the reliability of our analytical results and show the impact of various parameters on the system performance.
基金This study was financially supported by the National Key Research and Development Projects(2019YFD1000100,2018YFD1000301)the National Natural Science Foundation of China(31872058)+1 种基金Program of Young-Backbone Teacher of University in Henan Province(2018GGJS029)the Special Fund for Henan Agriculture Research System(S2014-11-G02).
文摘Drought stress is one of the major environmental obstacles that limit the production and development of apples(Malus domestica Borkh.).The role of melatonin is well known in the protection of plants under environmental stresses.In this study,we investigated the effect of melatonin on apple rootstock M.hupehensis Rehd under drought stress.The results showed that drought inhibited the growth of M.hupehensis and dramatically reduced root surface area,root volume,the number of tips and forks,and root diameter.Drought-induced growth inhibition was significantly decreased by adding melatonin.Net photosynthetic rate(Pn),intercellular CO_(2)concentration(Ci),stomatal conductance(Gs),transpiration rate(Tr),were markedly reduced under drought stress.However,the application of melatonin could mitigate the damage to the photosynthetic apparatus and increase the quantum yield of PSII photochemistry.Additionally,generation of hydrogen peroxide(H_(2)O_(2))and superoxide radicals(O_(2)^(•–))sharply increased in apple leaves after 4 days under drought stress,and the accumulation of electrolyte leakage(EL)represented oxidative stress,while by applying melatonin under drought stress,the generation of O_(2)^(•–)and H_(2)O_(2)were significantly reduced and protected the membrane from drought damages.These results suggest that the adverse effects of drought can be minimized by applying melatonin to apples.
基金by Key Research and Development Program of Shandong Province,No.2019JZZY010104Special Foundation for Taishan Scholars Program of Shandong Province,No.ts20190978and Science and Technology Innovation Development Program of Jinan,No.2020019082.
文摘BACKGROUND Colorectal cancer(CRC)is one of the most common malignant tumors of the digestive tract.Lymphatic metastases of this tumor are mostly confined to the regional lymph nodes,and distant supraclavicular lymph node metastases are very rare.CASE SUMMARY In this report,we describe a patient with sigmoid carcinoma and isolated synchronous supraclavicular lymph node metastases.A 56-year-old male presented with a left cervical mass that was confirmed as a lymph node metastasis from sigmoid cancer by several auxiliary examinations.After 6 cycles of chemotherapy with the 5-fluorouracil,leucovorin and oxaliplatin+cetuximab regimen,the sigmoid colon tumor and Virchow’s lymph node metastasis were significantly smaller than before treatment,and no new metastatic sites were observed.Considering the effects of chemotherapy on quality of life,resection of the primary tumor was performed followed by 4 cycles of chemotherapy with the original chemotherapy regimen.Virchow’s lymph node dissection was selected by mutual consultation between the patient and us.After the second surgery,the patient received capecitabine and cetuximab chemotherapy and did not experience recurrence or metastasis during follow-up.CONCLUSION In conclusion,supraclavicular lymph node metastasis without any other solid organ metastasis is a potential metastatic pathway for CRC.In addition,after resection of the primary lesion,postoperative chemotherapy combined with supraclavicular lymph node dissection is feasible for the treatment of patients with CRC and isolated synchronous Virchow’s lymph node metastases.
文摘Apple is one of the most important fruit trees in temperate zones, and is cultivated widely throughout the world. Drought stress affects the normal growth of apple tree, and further affects fruit yield and quality. The present study examined the effects of drought on photosynthesis and water use efficiency (WUE) of two apple cultivars (Honeycrisp and Yanfu 3) that differ in drought tolerance. The results showed that the photosynthetic rate decreased in response to drought stress for both cultivars, with significant differences in intensity. Values for net photosynthetic rate (Pn) in stressed Yanfu 3 remained significantly lower than in the controls, while, for Honeycrisp, only a slight drop in photosynthesis. Similarly, stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) were markedly reduced in Yanfu 3 under drought stress. However, Honeycrisp showed only minor changes. Under drought stress, the contents of Chl a, Chl b and Chl t in Yanfu 3 were all decreased significantly compared with the control. However, little difference in Honeycrisp was noted between stressed plants and controls. Values for WUE in stressed Yanfu 3 remained higher than in the controls from day 3 until the end of the experiment, while no significant difference was observed in Honeycrisp. Furthermore, Honeycrisp also exhibited superior physiological traits, as indicated by its anatomical and morphological characteristics. Therefore, we conclude that the superior drought tolerance of Honeycrisp was due to its anatomical and morphological characteristics, which possibly contributed to the maintenance of higher photosynthetic capacity than Yanfu 3.
基金supported by the IWHR Research&Development Support Program(No.SE0145B032021)the National Key Research and Development Program of China(No.2018YFC0507002).
文摘Mollisols are rich in organic matter,which makes them suitable for cultivation and for enhancing global food security.Mollisols are experiencing severe soil erosion due to overfarming and a lack of mainte-nance.Thus,suitable soil and water conservation measures(SWCMs)are needed to protect Mollisols.However,how SWCMs respond to changes in slope gradient and rainfall and their effective application area remain ambiguous.Using a long-term field observation dataset,meta-analysis,and statistical test methods,we reveal the typical erosion reduction effect of SWCMs and their responses to changes in slope gradient and rainfall.Next,we calculated a coupling factor,P.S,by slope gradient and rainfall in flood season to determine the effective SWCMs application threshold.Compared with bare land,no-tillage(NT),contour ridge tillage(CT),ridge hedgerows(RH),and terraced fields(TF)had an average erosion reduction coefficient of 91.5%.There was a significant exponential increase in the correlation between P.S and the soil erosion amount in plots with typical measures.According to this correlation and soil loss tolerance(200 t/km^(2)),the upper limits of PS(NT:564 mm;CT:885 mm;RH:1135 mm)were determined and utilized to determine the effective application areas(NT:311.40103 km^(2);CT:320.86103 km^(2);RH:323.72103 km^(2))at the plot scale.In wet years,the applicable area of SWCMs declined toward the low-elevation foothills and flat terrain.All the results are applicable when slope length within 20 m.These results provide a basis for the precise allocation of SWCMs in Mollisols area and promote the scientific utilization of Mollisols resources.
基金support from the Natural Science Basic Research Plan in Shaanxi Province of China (No.2020JM-087).
文摘Excellent impedance matching and high conduction loss are important factors for the preparation of high-performance electromagnetic wave(EMW)absorbing materials,but these two properties are of-ten contradictory.In this work,three absorbers with unique hollow structures,H-Ag/CuO@CuS,H-O-Ag/CuO@CuS,and H-P-Ag/CuO@CuS,are designed and synthesized by adopting hollow CuO@CuS with double shell as carrier and silver nitrate as the structural regulator.The more voids coming from hol-low structures,window-opened structures,and stacked pores improve the impedance matching of these absorbers,and the introduction of elemental Ag effectively regulates the conduction loss.Therefore,a balance between impedance matching and conduction loss is achieved to improve the reflection loss(RL)value and broadens the absorbing band of the absorbers.In comparison to H-Ag/CuO@CuS and H-O-Ag/CuO@CuS(hollow structure with open window)in which elemental Ag is uniformly dispersed in the CuO layer,H-P-Ag/CuO@CuS exhibits more excellent EMW absorption performance due to more voids and an optimized conductive network arising from Ag/CuO pieces distributed between the hol-low Ag/CuO@CuS particles and Ag distributed in the CuS layer.When the thickness is 2.3 mm,H-P-Ag/CuO@CuS provides an ultra-wide electromagnetic absorption band of 8.56 GHz(9.44-18 GHz),in which the RL<-10 dB and the minimum reflection loss of-41 dB.
基金supported by the National Program on Key Basic Research Project(2015CB901402)the National Natural Science Foundation of China(91629103,31670882, 81471066,81261120555,81672883,81401837,31071875,31200878, 31100946)+1 种基金the Science and Technology Commission of Shanghai Municipality(14430712100,11ZR1410000,16ZR1410000,16QA1401500)the Applied Basic Research Program of Science and Technology Department of Sichuan Province(2015JY0038)
文摘The tumor suppressor p53 protein is either lost or mutated in about half of all human cancers.Loss of p53 function is well known to influence cell spreading,migration and invasion.While expression of mutant p53 is not equivalent to p53 loss,mutant p53 can acquire new functions to drive cell spreading and migration via different mechanisms.In our study,we found that mutant p53 significantly increased cell spreading and migration when comparing with p53-null cells.RNA-Seq analysis suggested that Rho GTPase activating protein 44(ARHGAP44) is a new target of mutant p53,which suppressed AKHGAP44 transcription.ARHGAP44 has GAP activity and catalyze GTP hydrolysis on Cdc42.Higher level of GTP-Cdc42 was correlated with increase expression of mutant p53 and reduced ARHGAP44.Importantly,wt-ARHGAP44 but not mutant ARHGAP44(R291A) suppressed mutant p53 mediated cell spreading and migration.Bioinformatics analysis indicated lower expression of ARHGAP44 in lung carcinoma compared with normal tissues,which was verified by RT-qPCR using specimens from patients.More interestingly,ARHGAP44 mRNA level was lower in tumors with mutant p53 than those with normal p53.Collectively,our results disclose a new mechanism by which mutant p53 stimulates cell spreading and migration.
基金This work is jointly supported by the National Natural Science Foundation of China,Nos.81870809,81500886 and 31470920,and Tianjin Natural Science Foundation No.16JCYBJC28700Tianjin Health Science and Technology Project,ZD20021,and the China National Funds for Distinguished Young Scientists(no.51925104).
文摘Periodontitis is an inflammatory disease initiated by bacterial infection,developed by excessive immune response,and aggravated by high level of reactive oxygen species(ROS).Hence,herein,a versatile metal-organic framework(MOF)-based nanoplatform is prepared using mesoporous Prussian blue(MPB)nanoparticles to load BA,denoted as MPB-BA.The established MPB-BA nanoplatform serves as a shelter and reservoir for vulnerable immunomodulatory drug BA,which possesses antioxidant,anti-inflammatory and anti-bacterial effects.Thus,MPB-BA can exert its antioxidant,anti-inflammatory functions through scavenging intracellular ROS to switch macrophages from M1 to M2 phenotype so as to relieve inflammation.The underlying molecular mechanism lies in the upregulation of phosphorylated nuclear factor erythroid 2-related factor 2(Nrf2)to scavenge ROS and subsequently inhibit the nuclear factor kappa-B(NF-κB)signal pathway.Moreover,MPB-BA also exhibited efficient photothermal antibacterial activity against periodontal pathogens under near-infrared(NIR)light irradiation.In vivo RNA sequencing results revealed the high involvement of both antioxidant and anti-inflammatory pathways after MPB-BA application.Meanwhile,micro-CT and immunohistochemical staining of p-Nrf2 and p-P65 further confirmed the superior therapeutic effects of MPB-BA than minocycline hydrochloride.This work may provide an insight into the treatment of periodontitis by regulating Nrf2/NF-κB signaling pathway through photothermal bioplatform-assisted immunotherapy.
基金supported by the National Natural Science Foundation of China(No.51278055)the National Science and Technology Major Project(No.2012ZX07203-003)
文摘A study on the removal of Co(Ⅱ) from aqueous solutions by water treatment residuals(WTR)was conducted in batch conditions. The sorption process of Co(Ⅱ) followed pseudosecondorder kinetics, with 30 hr required to reach equilibrium. Using the Langmuir adsorption isotherm model, a relatively high maximum sorption capacity of 17.31 mg/g Co(Ⅱ) was determined. The adsorption of Co(Ⅱ) was dependent on pH values and was affected by the ionic strength. Results show that Co(Ⅱ) adsorption was a spontaneous endothermic process and was favorable at high temperature. Most of the adsorbed Co(Ⅱ) stayed on the WTR permanently, whereas only small amounts of adsorbed Co(Ⅱ) were desorbed. The shifting of peaks in FT-IR spectra indicated that Co(Ⅱ) interacted with the WTR surface through strong covalent bond formation with Fe(Al)–O functional groups. It was concluded that WTR can be a suitable material from which to develop an efficient adsorbent for the removal of Co(Ⅱ) from wastewater.
基金the National Natural Science Foundation of China(No.51608104 and No.51878139)Natural Science Foundation of Jiangsu Province(No.SBK2015043274)Jiangsu Southeast University Testing and Inspection Technology Company.
文摘Detailed survey and inspection of the structure of the lecture hall of the Anyuan Miners’Club were conducted during a restoration project.Nondestructive inspection measures were used to assess the physical and mechanical conditions of the structure.The brick and wood structures of the building were tested,the overall bearing capacity was calculated,and a safety appraisal was conducted in accordance with the codes and standards of the existing building.Inspection results provide architects and construction engineers with reliable data to develop a preservation plan and ensure the safety of the heritage building.
基金the National Natural Science Foundation of China(No.31772209)the Funda-mental Research Funds for the Central Universities of China(No.KYTZ201604)the Postgraduate Research&Practice Innova-tion Program of Jiangsu Province(KYCX20_0562).
文摘To screen novel antifungal agents targeting the succinate dehydrogenase(SDH),a series of pyrazole-4-carbohydrazides were rationally designed,synthesized,and characterized under the guidance of the structures of succinate dehydrogenase inhibitors(SDHIs).Bioassay results in vitro indicated that most of the target compounds exhibited excellent activity against Rhizoctonia solani(R.solani),Fusarium graminearum(F.graminearum),Botrytis cinerea(B.cinerea)and Colletotrichum capsica(C.cinerea).Compounds 7d,7l,7t and 7x were identified as the most promoting candidates,and their anti-F.graminearum EC50 values were as low as 0.56,0.47,0.46 and 0.49μg/mL,respectively,presenting the similar antifungal activity as that of the commonly used fungicide carbendazim(0.43μg/mL).The 3D-QSAR models were built for a systematic structure-activity relationship profile to explore more potent pyrazole-4-carbohydrazides as novel fungicides.Molecular docking of 7d,7l and 7r with SDH was performed to reveal the binding modes in active pocket and analyze the interactions between the molecules and the SDH protein.
基金Supported by grants from the Peking University School and Hospital of Stomatology(PKUSS20180205&PKUSS20130201).
文摘Background:There is limited evidence of the effects of local anesthesia(LA)on outcomes of non-surgical periodontal treatment(NSPT),in particular among the Chinese.This retrospective cohort study aimed to evaluate the effects of LA on short-term treatment outcomes of NSPT and to determine under what circumstances LA should be prescribed to improve these outcomes.Methods:Data from periodontal examinations of 3980 patients were used.The data were from 3-month re-evaluation records of an electronic periodontal charting record system in the Department of Periodontology of Peking University School and Hospital of Stomatology from June 2008 to January 2015.Descriptive analyses included changes in probing depth(PD)and the Mazza bleeding index(BI).Two-level(patient and tooth)logistic regression models and three-level(patient,tooth,and site)linear regression models were constructed to analyze the influence of LA on PD for all teeth/sites and teeth/sites with an initial PD≥5 mm.Decreases in PD and BI at sites under LA using the initial PD were also compared.Results:A significantly higher mean decrease in PD after NSPT was found in the LA group than in the no local anesthesia(NLA)group(0.98 vs.0.54 mm,t=24.12,P<0.001).A significantly higher probability of decreases was found in the LA group in BI(percentages of teeth with BI>1 and BI>2)for all teeth(16.7%vs.13.8%,t=3.75,P<0.001;34.7%vs.28.1%,t=6.73,P<0.001)and PD for teeth with PD≥5mm(32.3%vs.17.3%,t=28.48,P<0.001).The difference in PD between the LA and NLA groups increased as the initial PD increased.The difference between the two groups was 0.12 to 0.22 mm for sites with a baseline PD<7 mm;however,it increased to 0.41 to 1.37 mm for sites with a baseline PD≥7 mm.Conclusions:LA improved the decrease in PD after NSPT.Root debridement at sites with initial PD≥7 mm should be performed under routine LA.
基金supported in part by the National Natural Sciences Foundation of China(Nos.61771158,61871147,61831008,91638204 and 61525103)the Shenzhen Basic Research Program(Nos.JCYJ20170811154309920,JCYJ20170811160142808,and ZDSYS201707280903305)Guangdong Science and Technology Planning Project(No.2018B030322004).
文摘The increasing demands in terms of high data rate and quality of services over the hybrid satellite-terrestrial relay networks(HSTRN)have pushed for the development of millimeter-wave(mmWave)band high-throughput satellites(HTS)with multibeams.The next generation of mmWave multibeam HTS communication systems(HTSCS)is viewed as the backbone network to enhance the throughput of the HSTRN.The article first investigates the basic backbone topology architecture of HTSCS,and an M-state Markov channel for the Ka/Q/V band mmWave systems is reviewed.Then,we propose a long-term optimal power allocation scheme over two in-dependent and identical spot beams based on the partially observable Markov decision process(POMDP),which can partly mitigate the negative effects of severe weather conditions.The key conditions for selecting the optimal power allocation action in the multibeam HTSCS are given.Simulation results show that our POMDP-based power allocation scheme can enhance the long-term throughput of the HTSCS.