Tracking Regulatory Mechanism of Trace Fe on Graphene Electromagnetic Wave Absorption

Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the first time, the reduced graphene oxide(RGO) based absorbers are developed with regulatory absorption properties and the absorption mechanism of RGO is mainly originated from the carrier injection behavior of trace metal Fe nanosheets on graphene. Accordingly, the minimum reflection loss(RLmin) of Fe/RGO-2composite reaches-53.38 dB(2.45 mm), and the effective absorption bandwidth achieves 7.52 GHz(2.62 mm) with lower filling loading of 2 wt%. Using off-axis electron hologram testing combined with simulation calculation and carrier transport property experiments, we demonstrate here the carrier injection behavior from Fe to graphene at the interface and the induced charge accumulation and rearrangement, resulting in the increased interfacial and dipole polarization and the conductance loss. This work has confirmed that regulating the dielectric property of graphene itself by adding trace metals can not only ensure good impedance matching, but also fully exploit the dielectric loss ability of graphene at low filler content,which opens up an efficient way for designing lightweight absorbers and may be extended to other types materials.

Preparation of CIP@TiO_(2) composite with broadband electromagnetic wave absorption properties

Scholars aim for the improved impedance matching (Z) of materials while maintaining their excellent wave absorption properties. Based on the hydrolysis characteristics of isopropyl titanate, a simple preparation process for the coating of carbonyl iron powder(CIP) with TiO_(2) was designed. Given the TiO2coating, the Z of the CIP@TiO_(2) composite was adjusted well by decreasing the dielectric constant. Moreover, the interfacial polarization of CIP@TiO_(2) was enhanced. Ultimately, the electromagnetic-wave (EMW) absorption property of the CIP@TiO_(2)composite was improved substantially, the minimum reflection loss reached-46.07 dB, and the effective absorption bandwidth can reach 8 GHz at the composite thickness of 1.5 mm. Moreover, compared with CIP, the oxidation resistance of CIP@TiO_(2)showed remarkable improvement. The results revealed that the oxidation starting temperature of CIP@TiO_(2) as about 400℃,whereas the uncoated CIP had an oxidation starting temperature of approximately 250℃. Moreover, the largest oxidation rate temperature of CIP@TiO_(2) increased to around 550℃. This work opens up a novel strategy for the production of high-performance EMW absorbers via structural design.

中心孔型有晶状体眼人工晶状体植入术治疗高度近视的疗效

目的:观察中心孔型有晶状体眼人工晶状体(ICL V4c)植入术治疗高度近视的效果及对眼前节形态的改变。方法:前瞻性研究。选取2018-02/2021-03本院收治的高度近视患者100例200眼,均行ICL V4c植入术治疗。比较患者术前,术后6、12mo最佳矫正视力(BCVA)、裸眼视力(UCVA)、眼压、高阶像差、眼前节形态[前房角(ICA)、中央前房深度(ACD)、前房容积(ACV)、角膜厚度(CCT)、角膜曲率(K)]、明视与暗视下对比敏感度。结果:所有患者均完成随访。术后6、12mo UCVA、BCVA较术前明显改善(P<0.05);手术前后总高阶像差、水平彗差、垂直彗差比较均无差异(P>0.05),术后6、12mo球差、ICA、ACD、ACV均较术前明显减小(P<0.05);明视状态下,术后6、12mo 3.0、6.0c/d对比敏感度较术前明显增大(P<0.05);暗视状态下,术后6、12mo 6.0c/d对比敏感度较术前明显增大(P<0.05);手术前后CCT、K、眼压比较均无差异(P>0.05)。结论:ICL V4c植入术虽然减小了高度近视患者ICA、ACD、ACV,但能有效提高其视力与视觉质量。

Evaluating the weekly changes in terrestrial water storage estimated by two different inversion strategies in the Amazon River Basin

In this study,we estimated the weekly Gravity Recovery and Climate Experiment(GRACE)spherical harmonic(SH)solutions and regional mascon solutions using GRACE-based Geopotential Difference(GPD)data and investigated their abilities in retrieving terrestrial water storage(TWS)changes over the Amazon River Basin(ARB)from January 2003 to February 2013.The performance of the weekly GPD-SH and GPDmascon solutions was evaluated by comparing them with the weekly GFZ-SH solutions,Global Land Data Assimilation Systems(GLDAS)-NOAH hydrological model outputs,and monthly GFZ-SH,GPD-SH,and CSRmascon solutions in the spatio-temporal and spectral domains.The results demonstrate that the weekly GPD-SH and GPD-mascon present good consistency with the weekly GFZ-SH solutions and GLDAS-NOAH estimates in the spatio-temporal domains,but GPD-mascon presents stronger signal amplitudes and more spatial details.The comparison of the monthly average of weekly estimates and monthly solutions demonstrates that the weekly GPD-mascon and GFZ-SH with DDK1 filtering are close to the monthly CSRmascon and GFZ-SH solutions,respectively.However,the signal amplitudes of TWS changes from GPD-SH and GFZ-SH with 650 km Gaussian filtering are smaller than the monthly solutions,and the corresponding Root Mean Square Errors between the TWS change time series from the monthly average of weekly solutions and monthly estimates are 18.12 mm(GPD-mascon),18.81 mm(GFZ-SH-DDK1),24.93 mm(GPDSH-G650km),and 33.07 mm(GFZ-SH-G650km),respectively.Additionally,the TWS change time series derived from weekly solutions present more high-frequency time-varying information than monthly solutions.Furthermore,the 300 km Gaussian filtering can improve the signal amplitudes of TWS changes from the weekly GPD-SH solutions more than those with 650 km Gaussian filtering,but the corresponding noise level is higher.The weekly GPD-SH and GPD-mascon solutions can extend the application scopes of GRACE and provide good complements to the current GRACE monthly solutions.

Recent Progress on Hydrogeodesy in China

Modern geodetic technologies,including high-precision ground-based gravity measurements,satellite gravimetry,satellite altimetry,Global Navigation Satellite Systems(GNSS),and Interferometric Synthetic Aperture Radar(InSAR),offer a wealth of observations for monitoring global hydrological processes with exceptional accuracy and spatio-temporal resolutions.Mass redistribution and Earth’s surface deformation over land related to global and regional water cycling can be inferred from modern gravimetry,altimetry,GNSS,and InSAR techniques.Hydrogeodesy becomes an emerging field of geodesy aiming to analyze the changes of water in the Earth system.The paper introduces the China’s advances in hydrogeodesy in recent years.It brings together multiple geodetic teams’work from China,showcasing the application of modern geodetic technologies in the field of hydrology,including research on terrestrial water storage,groundwater storage,glaciers/ice sheets,and reservoir water storage.

美军联合任务环境下的能力试验方法分析

针对武器装备联合试验方法研究不够深入的问题,研究了美军面向联合试验的能力试验法;着重介绍了该方法的流程步骤,包括策划试验与评估策略、描述试验特征、制定试验计划、构建LVC-DE仿真环境、管理执行试验和评估试验能力六个部分,并指出和分析了该方法所具有的继承与兼容性、模块化驱动、线程式实现、灵活性、规范性等特点,以及在实践中开展的相关应用。

GRACE-based estimates of water discharge over the Yellow River basin

As critical component of hydrologic cycle, basin discharge is a key issue for understanding the hydrological and climatologic related to water and energy cycles. Combining GRACE gravity field models with ET from GLDAS models and precipitation from GPCP, discharge of the Yellow River basin are estimated from the water balance equation. While comparing the results with discharge from GLDAS model and in situ measurements, the results reveal that discharge from Mosaic and CLM GLDAS model can partially represent the river discharge and the discharge estimation from water balance equation could reflect the discharge from precipitation over the Yellow River basin.

Analysis of terrestrial water storage changes in the Shaan-Gan-Ning Region using GPS and GRACE/GFO

Both the Global Positioning System(GPS)and Gravity Recovery and Climate Experiment(GRACE)/GRACE Follow-On(GFO)provide effective tools to infer surface mass changes.In this paper,we combined GPS,GRACE/GFO spherical harmonic(SH)solutions and GRACE/GFO mascon solutions to analyze the total surface mass changes and terrestrial water storage(TWS)changes in the Shaan-Gan-Ning Region(SGNR)over the period from December 2010 to February 2021.To improve the reliability of GPS inversion results,an improved regularization Laplace matrix and monthly optimal regularization parameter estimation strategy were employed to solve the ill-posed problem.The results show that the improved Laplace matrix can suppress the edge effects better than that of the traditional Laplace matrix,and the corre-lation coefficient and standard deviation(STD)between the original signal and inversion results from the traditional and improved Laplace matrix are 0.84 and 0.88,and 17.49 mm and 15.16 mm,respectively.The spatial distributions of annual amplitudes and time series changes for total surface mass changes derived from GPS agree well with GRACE/GFO SH solutions and mascon solutions,and the correlation coefficients of total surface mass change time series between GPS and GRACE/GFO SH solutions,GPS and GRACE/GFO mascon solutions are 0.80 and 0.77.However,the obvious differences still exist in local regions.In addition,the seasonal characteristics,increasing and decreasing rate of TWS change time series derived from GPS,GRACE/GFO SH and mascon solutions agree well with the Global Land Data Assimilation System(GLDAS)hydrological model in the studied area,and generally consistent with the precipitation data.Meanwhile,TWS changes derived from GPS and GRACE mascon solutions in the SGNR are more reliable than those of GRACE SH solutions over the period from January 2016 to June 2017(the final operation phase of the GRACE mission).

Simulation analysis of regional surface mass anomalies inversion based on different types of constraints

Surface mass anomalies estimated by mass concentration(mascon)approach using Gravity Recovery and Climate Experiment(GRACE)observations with regularization constraints generally present higher spatial resolution than the spheric harmonic(SH)solutions.To analyze the influence of different types of constraints on the estimation of mascon solutions,we carried out a closed-loop simulation experiment to estimate surface mass anomalies over South America based on simulated GRACE intersatellite geopotential differences.Tikhonov regularization with spatial constraint(SC),uniform weighting constraint(UWC),and a prior information constraint(APC)were employed to stabilize the mascon solutions,and the corresponding optimal regularization parameters were determined based on the minimum residual root-mean-square(RMS)criterion.The results show that mascon solutions estimated under different types of constraints are consistent and equivalent when the optimal regularization parameters are selected.The spatial distributions and main characteristics of regional surface mass anomalies estimated by the three types of constraints agree well,and the values of residual RMS with different constraints are very close.But due to the smoothing effect of regularization,the signal strength of mascon solutions is a bit weaker than that of original true signal,especially in the regions with strong signals.In addition,due to the ill-conditioned problem is more serious for higher grid resolution,the relative contribution of the three types of constraints to the final mascon solutions would be stronger.The results show that the averages of relative contribution percentages of these constraints for 2°×2° mascon grids are 80%-90%,while the corresponding values for 4°×4° mascon grids are 30%-60%.However,based on the minimum residual RMS criterion,the accuracy of estimation results is not affected by the type of constraints and their relative contribution to the final mascon solutions.

Scattering Inversion Study for Suspended Label-Free Lymphocytes with Complex Fine Structures

Objective and Impact Statement.Distinguishing malignant lymphocytes from normal ones is vital in pathological examination.We proposed an inverse light scattering(ILS)method for label-free suspended lymphocytes with complex fine structures to identify their volumes for pathological state.Introduction.Light scattering as cell’s“fingerprint”provides valuable morphology information closely related to its biophysical states.However,the detail relationships between the morphology with complex fine structures and its scattering characters are not fully understood.Methods.To quantitatively inverse the volumes of membrane and nucleus as the main scatterers,clinical lymphocyte morphologies were modeled combining the Gaussian random sphere geometry algorithm by 750 reconstructed results after confocal scanning,which allowed the accurate simulation to solve ILS problem.For complex fine structures,the specificity for ILS study was firstly discussed(to our knowledge)considering the differences of not only surface roughness,posture,but also the ratio of nucleus to the cytoplasm and refractive index.Results.The volumes of membrane and nucleus were proved theoretically to have good linear relationship with the effective area and entropy of forward scattering images.Their specificity deviations were less than 3.5%.Then,our experimental results for microsphere and clinical leukocytes showed the Pearson product-moment correlation coefficients(PPMCC)of this linear relationship were up to 0.9830~0.9926.Conclusion.Our scattering inversion method could be effectively applied to identify suspended label-free lymphocytes without destructive sample pretreatments and complex experimental systems.

Facile fabrication of graphene/g-C_(3)N_(4) for electromagnetic wave absorption

With the development of the miniaturization of electronic equipment and lightweight weapon equipment,there are new requirements for electromagnetic wave absorption material(EMWAM).EMWAM has outstanding electromagnetic wave absorption properties and lightweight characteristics become an important direction of research.In this study,graphene/g-C_(3)N_(4)(GGCN)EMWAM was first synthesized in situ by simple heat treatment,in which the g-C_(3)N_(4) had a porous structure and dispersed on the surface of graphene.The impedance matching of the GGCN was well adjusted by decreasing the dielectric constant and attenuation constant due to the g-C_(3)N_(4) semiconductor property and the graphite-like structure.The EMW loss mechanism of GGCN was also analyzed by simulating GGCN’s electric field mode distribution and resistance loss power density.The analysis result shows that the distribution of g-C_(3)N_(4) among GGCN sheets can produce more polarization effects and relaxation effects by increasing the lamellar spacing.Furthermore,the polarization loss of GGCN could be increased successfully by porous g-C_(3)N_(4).Ultimately,the EMW absorption property of GGCN is optimized significantly,and GGCN exhibits excellent EMW absorption performance.When the thickness is 2 mm,the effective absorption bandwidth(EAB)can reach 4.6 GHz,and when the thickness is 4.5 mm,the minimum reflection loss(RLmin)at 4.56 GHz can reach-34.69 dB.Moreover,the practical application of EMWAM was studied by radar cross-section(RCS)simulation,showing that GGCN has a good application prospect.

Disulfiram ameliorates STING/MITA-dependent inflammation and autoimmunity by targeting RNF115

STING(also known as MITA)is an adaptor protein that mediates cytoplasmic DNA-triggered signaling,and aberrant activation of STING/MITA by cytosolic self-DNA or gain-of-function mutations causes severe inflammation.Here,we show that STING-mediated inflammation and autoimmunity are promoted by RNF115 and alleviated by the RNF115 inhibitor disulfiram(DSF).Knockout of RNF115 or treatment with DSF significantly inhibit systemic inflammation and autoimmune lethality and restore immune cell development in Trex1^(–/–)mice and STING^(N153S/WT) bone marrow chimeric mice.In addition,knockdown or pharmacological inhibition of RNF115 substantially downregulate the expression of IFN-α,IFN-γand proinflammatory cytokines in PBMCs from patients with systemic lupus erythematosus(SLE)who exhibit high concentrations of dsDNA in peripheral blood.Mechanistically,knockout or inhibition of RNF115 impair the oligomerization and Golgi localization of STING in various types of cells transfected with cGAMP and in organs and cells from Trex1^(–/–)mice.Interestingly,knockout of RNF115 inhibits the activation and Golgi localization of STINGN153S as well as the expression of proinflammatory cytokines in myeloid cells but not in endothelial cells or fibroblasts.Taken together,these findings highlight the RNF115-mediated cell type-specific regulation of STING and STINGN153S and provide potential targeted intervention strategies for STING-related autoimmune diseases.

Effect of boron doping on waterproof and dielectric properties of polyborosiloxane coating on SiO2f/SiO2 composites

A hydrophobic coating of the silica fiber reinforced silica composites(SiO2f/SiO2) was synthesized by sol-gel method using methyltriethoxy-silane(MTES) and boric acid(B(OH)3) as raw materials. The relationship among boron doping, chemical structure of precursors and durability of hydrophobic coatings was discussed. The Si-O-B and methyl groups were successfully introduced in the gel precursors according to the FT-IR and XPS results. The resins were filled in the internal and surface holes of the SiO2f/SiO2 composites partially or completely, which is beneficial to reduce the physical adsorption of the moisture. In addition, hydroxyl groups of the SiO2f/SiO2 composites reacted with the resins and hydrophobic methyl groups were introduced, leading to the reduction of the chemical adsorption of water. Also, the boron doping was beneficial to enhancing the physical cross-linking between the coating and the SiO2f/SiO2 composites, and improved the adhesion of the coating to the substrate. The results show that the optimal hydrophobic coating with contact angle 130.33°, moisture absorption 0.33% and adhesion level 1 is obtained when the molar ratio of MTES to B(OH)3 is 10:4. The real permittivity of M10B4 is constant in the range of 2.32–2.51 and the dielectric tangent loss is constant in the range of 5.5 × 10-4–8.7 × 10-3. The hydrophobic coating has excellent dielectric properties.

Carbonized wood with ordered channels decorated by NiCo_(2)O_(4) for lightweight and high-performance microwave absorber

Wood-derived carbon has a 3D porous framework composed of through channels along the growth direction,which is a suitable matrix for preparing electromagnetic wave(EMW)absorbing materials with low cost,light weight,and environmental friendliness.Herein,the carbonized wood decorated by short cone-like NiCo_(2)O_(4)(NiCo_(2)O_(4)@CW)with highly ordered straight-channel architecture was successfully manufactured through a facile calcination procedure.The horizontal arrangement of the through channels of NiCo_(2)O_(4)@CW(H-NiCo_(2)O_(4)@CW)exhibits a strong reflection loss value of-64.0 dB at 10.72 GHz with a thickness of 3.62 mm and a low filling ratio of 26 wt%(with the density of 0.98 g-cnf3),and the effective absorption bandwidth(EAB)is 8.08 GHz(9.92-18.0 GHz)at the thickness of 3.2 mm.The excellent microwave absorption(MA)property was ascribed to the ordered-channel structure with abundant interfaces and defects from NiCo_(2)O_(4)@CW,which could promote the interfacial polarization and dipole polarization.What is more,this advantageous structure increased the multiple reflections and scattering.Finite element analysis(FEA)simulation is carried out to detect the interaction between the prepared material and EMW when the ordered channels are arranged in different directions.This research provides a low-cost,sustainable,and environmentally friendly strategy for using carbonized wood to fabricate microwave absorbers with strong attenuation capabilities and light weight.

Friction and wear behavior of carbon fiber reinforced lithium aluminosilicate composites sliding against GCr15 steel

Carbon fibers reinforced lithium aluminosilicate matrix composites(Cf/LAS)were prepared by slurry infiltration combined with a hot press procedure.The friction,wear behavior,and wear mechanisms of Cf/LAS composites under dry sliding conditions were investigated.The results show that the coefficient of friction(COF)initially increased with the increase in carbon fiber content,and reached the maximum value of 0.20 for the 33%Cf/LAS composite.The COF increased sharply with increasing sample temperature from RT to 300℃.The COF remained stable in the temperature range of 300–500℃.The two wear mechanisms of LAS glass-ceramics are fatigue wear and abrasive wear.The Cf/LAS composites demonstrate slight spalling and shallow scratches.These results show that carbon fibers improve the mechanical properties and wear resistance of Cf/LAS composites.

Combined targeting of CCL7 and Flt3L to promote the expansion and infiltration of cDC1s in tumors enhances T-cell activation and anti-PD-1 therapy effectiveness in NSCLC

mmune checkpoint inhibitors(ICIs),represented by anti-PD-1/PD-L1 antibodies,have been widely applied in various cancers,and the efficacy of ICIs is closely associated with the tumor immune microenvironment(TIME)[1,2].We previously demonstrated that the alveolar macrophage-derived chemokine CCL7 recruited conventional type 1 dendritic cells(cDC1s)to remodel the TIME,thereby promoting the expansion of T cells to inhibit non-small cell lung cancer(NSCLC)progression in KrasLSL-G12D/+Tp53fl/fl(KP)and KrasLSL-G12D/+Lkb1fl/fl(KL)mouse models[3].Here,we showed that the fusion protein PD-1Ab7,in which CCL7 was fused with the single-chain variable fragment region(scFv)of an anti-PD-1 antibody(PD-1Ab),exhibited antitumor activity superior to that of PD-1Ab in a manner dependent on cDC1s.In addition,Fms-like tyrosine kinase 3 ligand(Flt3L)synergized with PD-1Ab7 to inhibit NSCLC progression in both the KP and the KL mouse models.Mechanistically,Flt3L promoted the generation and proliferation of cDC1s,whereas PD-1Ab7 increased the infiltration and migration of cDC1s in the TIME to potentiate the activation and proliferation of T cells.These findings not only highlight the essential roles of the PD-1Ab-based chemokine fusion strategy in targeting cDC1s and T cells to potentiate the efficacy of ICIs for cancer prevention but also provide therapeutic lead molecules for antitumor therapy.

Review of risk factors for human echinococcosis prevalence on the Qinghai-Tibet Plateau, China: a prospective for control options

Objective: Echinococcosis is a major parasitic zoonosis of public health importance in western China. In 2004, the Chinese Ministry of Health estimated that 380,000 people had the disease in the region. The Qinghai-Tibet Plateau is highly co-endemic with both alveolar echinococcosis (AE) and cystic echinococcosis (CE). In the past years, the Chinese government has been increasing the financial support to control the diseases in this region. Therefore, it is very important to identify the significant risk factors of the diseases by reviewing studies done in the region in the past decade to help policymakers design appropriate control strategies. Review: Selection criteria for which literature to review were firstly defined. Medline, CNKI (China National Knowledge Infrastructure), and Google Scholar were systematically searched for literature published between January 2000 and July 2011. Significant risk factors found by single factor and/or multiple factors analysis were listed, counted, and summarized. Literature was examined to check the comparability of the data;age and sex specific prevalence with same data structures were merged and used for further analysis. A variety of assumed social, economical, behavioral, and ecological risk factors were studied on the Plateau. Those most at risk were Tibetan herdsmen, the old and female in particular. By analyzing merged comparable data, it was found that females had a significant higher prevalence, and a positive linearity relationship existed between echinococcosis prevalence and increasing age. In terms of behavioral risk factors, playing with dogs was mostly correlated with CE and/or AE prevalence. In terms of hygiene, employing ground water as the drinking water source was significantly correlated with CE and AE prevalence. For definitive hosts, dog related factors were most frequently identified with prevalence of CE or/and AE;fox was a potential risk factor for AE prevalence only. Overgrazing and deforestation were significant for AE prevalence only. Conclusion: Tibetan herdsmen communities were at the highest risk of echinococcosis prevalence and should be the focus of echinococcosis control. Deworming both owned and stray dogs should be a major measure for controlling echinococcosis;treatment of wild definitive hosts should also be considered for AE endemic areas. Health education activities should be in concert with the local people's education backgrounds and languages in order to be able to improve behaviors. Further researches are needed to clarify the importance of wild hosts for AE/CE prevalence, the extent and range of the impacts of ecologic changes (overgrazing and deforestation) on the AE prevalence, and risk factors in Tibet.

Interruption of schistosomiasis transmission in mountainous and hilly regions with an integrated strategy:a longitudinal case study in Sichuan,China

Background:Schistosomiasis remains a major public health concern in China.Since 2004,an integrated strategy was developed to control the transmission of Schistosoma japonicum in China.However,the long-term effectiveness of this integrated strategy for the interruption of schistosomiasis transmission remains unknown in the mountainous and hilly regions of China until now.This longitudinal study aims to evaluate the effectiveness of the integrated strategy on transmission interruption of schistosomiasis in Sichuan Province from 2005 through 2014.Methods:The data regarding replacement of bovines with machines,improved sanitation,access to clean water,construction of public toilets and household latrines,snail control,chemotherapy,and health education were captured from the annual report of the schistosomiasis control programmes in Sichuan Province from 2005 to 2014,and S.japonicum infection in humans,bovines and snails were estimated to evaluate the effectiveness of the integrated strategy.Results:During the 10-year period from 2005 through 2014,a total of 536568 machines were used to replace bovines,and 3284333 household lavatories and 15523 public latrines were built.Tap water was supplied to 19116344 residents living in the endemic villages.A total of 230098 hm2 snail habitats were given molluscicide treatment,and 357233 hm2 snail habitats received environmental improvements.There were 7268138 humans and 840845 bovines given praziquantel chemotherapy.During the 10-year study period,information,education and communication(IEC)materials were provided to village officers,teachers and schoolchildren.The 10-year implementation of the integrated strategy resulted in a great reduction in S.japonicum infection in humans,bovines and snails.Since 2007,no acute infection was detected,and no schistosomiasis cases or infected bovines were identified since 2012.In addition,the snail habitats reduced by 62.39%in 2014 as compared to that in 2005,and no S.japonicum infection was identified in snails since 2007.By 2014,88.9%of the endemic counties achieved the transmission interruption of schistosomiasis and transmission control of schistosmiasis was achieved in the whole province in 2008.Conclusion:The government-directed and multi-department integrated strategy is effective for interrupting the transmission of schistosomiasis in the mountainous and hilly regions of China.

Seasonal pattern of Echinococcus re-infection in owned dogs in Tibetan communities of Sichuan, China and its implications for control

Background:Human cystic echinococcosis(CE)and alveolar echinococcosis(AE)are highly endemic in Tibetan communities of Sichuan Province.Previous research in the region indicated that domestic dog was the major source of human infection,and observations indicated that domestic dog could have more access to intermediate hosts of Echinococcus spp.:both domestic livestock(CE)viscera and small mammals(AE),in early winter and again in spring.We hypothesized that there would therefore be a significant increase in the risk of canine infection with Echinococcus spp.in these two seasons and conducted a reinfection study to investigate this further.Methods:Faecal samples were collected from owned dogs in seven townships in Ganze Tibetan Autonomous Prefecture(Sichuan Province,China),and Echinococcus spp.infection status was determined using copro-antigen ELISA.Dogs were sampled in April(spring),July(early summer),September/October(autumn/early winter)and December(winter)in 2009;and in April(spring)2010.Dogs were treated with praziquantel following each of the five sample collections to eliminate any tapeworms.Information on dog sex,age and body weight was also collected.The t-test,Fisher’s exact test,Poisson regression and logistic regression were used to compare means and prevalences,and to identify factors associated with infection status.Results:The proportion of female dogs was significantly lower than that of male dogs;female dogs had significantly higher(22.78%)baseline copro-ELISA prevalence than males(11.88%).Dog body weight,sex,age,county and previous infection status at any sampling point had no influence on the re-infection prevalence in general.Poisson regression did not found a significant influence on the re-infection prevalence due to different deworming/sampling time spans.Dogs exhibited significantly higher re-infection prevalences in spring and early summer of 2009 and in early winter between September/October and December of 2009,suggesting a higher infection pressure in these seasons comparing with other seasons.Conclusion:Following praziquantel treatment,dog body weight,sex,age,county,deworming time span and previous infection status at any sampling point had no influence on the re-infection prevalence in the region in general.The differences between re-infection prevalences were probably due to the seasonality in Echinoccocus spp.infection pressure in the region.Early winter,spring and early summer should be important seasons for optimal dog deworming intervention in these Tibetan communities.

A multiplex PCR for differential detection of Echinococcus granulosus sensu stricto,Echinococcus multilocularis and Echinococcus canadensis in China

Background:Echinococcosis caused byEchinococcus is one of the most major infectious diseases in north-west highland of China.E.granulosus sensu strict,E.multilocularis,andE.canadensis are known to be the only three species related to human health transmitting in the areas.To achieve targeted treatment and control of echinococcosis,the accurate identification and discrimination of the species are important.However,currently the available diagnostic approaches do not present ideal results either in accuracy or efficiency.Methods:In the study,a set of primers were designed to aim at the three human-pathogenicEchinococcus species in China.The one-step multiplex PCR assay was developed and evaluated for the specificity and sensitivity.A total of 73parasitic lesions and 41 fecal materials obtained from human and various animals collected in the clinic and the field were tested to assess the applicability of this method.Results:The multiplex PCR effectively detected the individual DNA from the targeted species and their random mixtures generating with distinguishable expected size of products.The detection limit of the assay for each of the three species was 5 pg/μl when they were tested separately.When DNA mixtures of the targeted species containing the same concentration were used as templates,the lowest amount of DNA which can be detected was 50 pg/μl,10 pg/μl and 5 pg/μl forE.granulosus s.s.,E.multilocularis,andE.canadensis respectively.No cross-reactivity was observed when DNA from eight genetically close species was used as control templates.The multiplex PCR identifications of all samples were in line with the original sequencing results except for those infected withE.shiquicus,which showed negative signals in the developed assay.Of all the tested stool materials,16 were previously found positive forEchinococcus by visual and microscopic examination.Among these 16 samples,13 were confirmed by the multiplex PCR,and the other three tested negative.Additionally,the multiplex PCR identified another 14 positive feces from the remained 25 stool samples which absence of worms.Conclusions:The developed multiplex PCR shows advantages in fast diagnosis and large-scale epidemiological investigation,which proven to be a promising tool utilized in clinic and surveillance system.