The present paper carries a corpus-based study on the use of adverbial conjuncts in order to reveal the difference between Chinese EFL learners and native speakers. It is based on two corpora of CLEC and LOB. Accordin...The present paper carries a corpus-based study on the use of adverbial conjuncts in order to reveal the difference between Chinese EFL learners and native speakers. It is based on two corpora of CLEC and LOB. According to the data-driven analysis, the research shows that Chinese EFL learners tend to overuse listing conjuncts while underuse other categories. This may result from the limitation of writing topics and the lack of cohesion in their writings. Besides, the incomplete understanding of adverbial conjuncts may cause the avoiding of certain conjuncts and thus turning to the easier listing conjuncts for help.展开更多
Linking words,also called transition words,are quite useful in English expressions.Linking words are not the same as conjunctions,although some conjunctions can function as linking words.Here's a clear explanation...Linking words,also called transition words,are quite useful in English expressions.Linking words are not the same as conjunctions,although some conjunctions can function as linking words.Here's a clear explanation for English learners,followed by a wellorganized passage on the functions of linking words in writing and communication.展开更多
AIM:To investigate the factors influencing meibomian gland atrophy(MGA)in children with allergic conjunctivitis(AC).METHODS:In this cross-sectional study,60 children with AC aged 6-17y and 20 age-matched children with...AIM:To investigate the factors influencing meibomian gland atrophy(MGA)in children with allergic conjunctivitis(AC).METHODS:In this cross-sectional study,60 children with AC aged 6-17y and 20 age-matched children without signs or symptoms of ocular surface dysfunction were included.Information on the duration of AC,untreated time,electronic screen time(EST),outdoor exercise time,body mass index(BMI),and frequency of eye rubbing was collected using a health history form.The Standard Patient Evaluation of Eye Dryness(SPEED)score was used for dry eye assessment.Images of the meibomian glands(MGs)were obtained using Keratograph 5M,and the rate of meibomian gland atrophy(MGAR)was calculated using Image J.All subjects underwent routine eye examinations.RESULTS:The average age of the AC group was 10.43±2.75y(range 6-17y)and 10.35±3.42y(range 6-14y)in the control group.The MGAR in the AC group was 33.42%±11.91%,significantly higher than that in the control group(18.10%±11.74%,P<0.001).Moreover,the MGAR in younger children(aged 12 and below)was significantly higher than in older children(P<0.05).Multi-factor linear regression analysis revealed that EST non-projector was a risk factor for MGAR(β=0.332,95%CI 0.04-0.22,P=0.004),while outdoor exercise time was a protective factor against MGAR(β=-0.407,95%CI-0.39 to-0.10,P=0.001).The untreated time of AC was identified as a risk factor for MGAR(β=0.24,95%CI 0.07-1.98,P=0.037),and the frequency of eye rubbing was associated with MG distortion score(P=0.00).CONCLUSION:Children with AC exhibit exacerbate MGA,with the degree of atrophy worsening as the untreated time of AC prolongs.Children under 12 years old show a higher MGAR,and EST non-projector negatively impacts MGA,while increased outdoor exercise time acts as a protective factor against MGA.展开更多
Data privacy leakage has always been a critical concern in cloud-based Internet of Things(IoT)systems.Dynamic Symmetric Searchable Encryption(DSSE)with forward and backward privacy aims to address this issue by enabli...Data privacy leakage has always been a critical concern in cloud-based Internet of Things(IoT)systems.Dynamic Symmetric Searchable Encryption(DSSE)with forward and backward privacy aims to address this issue by enabling updates and retrievals of ciphertext on untrusted cloud server while ensuring data privacy.However,previous research on DSSE mostly focused on single keyword search,which limits its practical application in cloud-based IoT systems.Recently,Patranabis(NDSS 2021)[1]proposed a groundbreaking DSSE scheme for conjunctive keyword search.However,this scheme fails to effectively handle deletion operations in certain circumstances,resulting in inaccurate query results.Additionally,the scheme introduces unnecessary search overhead.To overcome these problems,we present CKSE,an efficient conjunctive keyword DSSE scheme.Our scheme improves the oblivious shared computation protocol used in the scheme of Patranabis,thus enabling a more comprehensive deletion functionality.Furthermore,we introduce a state chain structure to reduce the search overhead.Through security analysis and experimental evaluation,we demonstrate that our CKSE achieves more comprehensive deletion functionality while maintaining comparable search performance and security,compared to the oblivious dynamic cross-tags protocol of Patranabis.The combination of comprehensive functionality,high efficiency,and security makes our CKSE an ideal choice for deployment in cloud-based IoT systems.展开更多
This study investigates the transmission dynamics of conjunctivitis using stochastic delay differential equations(SDDEs).A delayed stochastic model is formulated by dividing the population into five distinct compartme...This study investigates the transmission dynamics of conjunctivitis using stochastic delay differential equations(SDDEs).A delayed stochastic model is formulated by dividing the population into five distinct compartments:susceptible,exposed,infected,environmental irritants,and recovered individuals.The model undergoes thorough analytical examination,addressing key dynamical properties including positivity,boundedness,existence,and uniqueness of solutions.Local and global stability around the equilibrium points is studied with respect to the basic reproduction number.The existence of a unique global positive solution for the stochastic delayed model is established.In addition,a stochastic nonstandard finite difference scheme is developed,which is shown to be dynamically consistent and convergent toward the equilibrium states.The scheme preserves the essential qualitative features of the model and demonstrates improved performance when compared to existing numerical methods.Finally,the impact of time delays and stochastic fluctuations on the susceptible and infected populations is analyzed.展开更多
Objective To observe the clinical efficacy of bloodletting at Erjian(耳尖EX- HN 6) combined with traditional Chinese herbal medication (heat-clearing I recipe) ultrasonic atomization in treatment of acute catarrha...Objective To observe the clinical efficacy of bloodletting at Erjian(耳尖EX- HN 6) combined with traditional Chinese herbal medication (heat-clearing I recipe) ultrasonic atomization in treatment of acute catarrhal conjunctivitis (fulminant wind and invading fever). Method One hundred and twenty- two patients (244 eyes) were randomly divided into 3 groups. In group A (40 cases, 80 eyes), levofloxacin hydrochloride eye drops were administrated for four times per day; in group B (42 cases, 84 eyes), "heat-clearing I recipe" ultrasonic atomization was applied for twice per day with 20 rain for each time; and in group C (40 cases, 80 eyes), bloodletting at EX-HN 6 was applied before ultrasonic atomization on the first 3 days of treatment, with once per day. Result (1) The total effective rate of group C was 100.00% which was significantly superior to 88.75% in group A (P〈0.05); (2) the average course of treatment of clinical cured patients of group C was significantly shorter than those of group A and group B (P〈0.05). Conclusion It is indicated from this study that "heat-clearing I recipe" ultrasonic atomization combined with bloodletting at EX-HN 6 in treatment of acute catarrhal conjunctivitis (fulminant wind and invading fever) have definite efficacy, its clinical efficacy is significantly superior to traditional levofloxacin treatment, and its course of treatment is obviously shorter than that of simple traditional Chinese medicine ultrasonic atomization. Cold ultrasonic atomization can effectively relieve local burning sensation, obviously relieve reddening and swelling and heat pain of patients, and ease subjective discomfort and emotional tension of patients.展开更多
The effects of BCG PSN on T cell subsets and cytokines in vernal conjunctivitis were observed. The level of total IgE was quantitatively determined before and after treatment with BCG PSN by allergen diagnostic ins...The effects of BCG PSN on T cell subsets and cytokines in vernal conjunctivitis were observed. The level of total IgE was quantitatively determined before and after treatment with BCG PSN by allergen diagnostic instrument in vitro . The content of T cell subsets of peripheral blood and cytokine were determined by using indirect immune fluorescence method, and IL 4 and INF γ were quantified by ELISA. The results showed that the level of total IgE was substantially reduced ( P <0.01) after treatment in the BCG PSN group. Meanwhile, CD + 8 was decreased, CD + 4 and CD + 4/CD + 8 ratio elevated with significant differences ( P <0.05) as compared with pre treatment results. The changes in total IgE, CD + 8 ,CD + 4 and CD + 4/CD + 8 ratio after treatment also presented significant differences ( P <0.05) between BCG PSN group and routine treatment group. The level of IL 4 in serum declined ( P <0.05) after treatment in the BCG PSN group, and INF γ went up ( P <0 05). IL 4 and INF γ in serum showed significant differences ( P <0.05) between two groups after treatment. It is concluded that BCG PSN has a bi directional immunoregulating effect. It can bring CD + 4 and CD + 8 into homeostasis, thereby preventing the occurrence of anaphylaxis. At the same time, BCG PSN can restrain Th 2, decrease the synthesis of IL 4, switch the balance of Th l/Th 2 to Th 1 side, boost up the predominance of Th 1 relatively, which is propitious to perennial stabilization and recovery of vernal conjunctivitis.展开更多
AIM: To assess the efficacy of topical Semaphorin 3A(SEMA3A) in the treatment of allergic conjunctivitis.METHODS: Experimental allergic conjunctivitis(EAC)mice model induced by short ragweed pollen(SRW) in 4-week-old ...AIM: To assess the efficacy of topical Semaphorin 3A(SEMA3A) in the treatment of allergic conjunctivitis.METHODS: Experimental allergic conjunctivitis(EAC)mice model induced by short ragweed pollen(SRW) in 4-week-old of BALB/c mice, mice were evaluated using haematoxylin and eosin(H&E) staining, immunofluor-escence and light microscope photographs. Early phase took the samples in 24 h after instillation and late phase took the samples between 4 to 14 d after the start of treatment. The study use of topical SEMA3A(10 U, 100 U,1000 U) eye drops and subconjunctival injection of SEMA3 A with same concentration. For comparison, five types of allergy eyedrops were quantified using clinical characteristics.· RESULTS: Clinical score of composite ocular symptoms of the mice treated with SEMA3 A were significantly decreased both in the immediate phase and the late phase compared to those treated with commercial ophthalmic formulations and non-treatment mice. SEMA3 A treatment attenuates infiltration of eosinophils entering into conjunctiva in EAC mice. The score of eosinophil infiltration in the conjunctiva of SEMA3 A 1000 U-treated group were significantly lower than low-concentration of SEMA3 A treated groups and non-treated group. SEMA3 A treatment also suppressed T-cell proliferation in vitro and decreased serum total Ig E levels in EAC mice. Moreover, treatment of SEMA3 A suppressed Th2-related cytokines(IL-5, IL-13 and IL-4)and pro-inflammatory cytokines(IFN-γ, IL-17 and TNF-α)release, but increased regulatory cytokine IL-10 concentration in the conjunctiva of EAC mice.CONCLUSION: SEMA3 A as a biological agent, showed the beneficial activity in ocular allergic processes with the less damage to the intraocular tissue. It is expected that SEMA3 A may be contributed in patients with a more severe spectrum of refractory ocular allergic diseases including allergic conjunctivitis in the near future.展开更多
AIM: To demonstrate the effects of two different types of allergic conjunctivitis on severity of keratoconus (KC). ·METHODS: We retrospectively reviewed the medical records of 171 KC patients referred between Jun...AIM: To demonstrate the effects of two different types of allergic conjunctivitis on severity of keratoconus (KC). ·METHODS: We retrospectively reviewed the medical records of 171 KC patients referred between June 2010 and June 2011. The KC patients were divided into 3 groups as KC (group A), KC with vernal keratoconjunctivitis (VKC) (group B) and KC with allergic conjunctivitis (AC) (group C). Main outcome measures were demographic and ocular clinical features including age at presentation, gender, spherical equivalent (SE), best spectacle corrected visual acuity (BCVA), mean keratometric measurement (Km), central corneal thickness (CCT), and intraocular pressure (IOP). Groups were compared in term of study variables. · RESULTS: The median age at presentation was significantly lower in group B (P 【0.001). According to the median SE (P =0.003), BCVA(P =0.022), Km(P 【0.001), CCT (P =0.015) and Amsler-Krumeich classification (P 【 0.001), KC was more severe in group B. There was no significant difference in terms of IOP and corrected IOP among the groups (P =0.44), however there were 4 patients who had increased corrected IOP developed after topical corticosteroid use in group B. The differences among the groups persisted even after controlling for age and gender. · CONCLUSION: Our findings demonstrated a more severe KC in VKC patients despite their younger age which suggests evaluation of VKC patients as a separate group in keratoconus disease.展开更多
AIM: To evaluate the relative efficacy and safety of besifloxacin for treatment of acute bacterial conjunctivitis.METHODS: A comprehensive search in PubMed, EMBASE Web of Science, Cochrane Central Database and CNKI wa...AIM: To evaluate the relative efficacy and safety of besifloxacin for treatment of acute bacterial conjunctivitis.METHODS: A comprehensive search in PubMed, EMBASE Web of Science, Cochrane Central Database and CNKI was undertaken for randomized controlled trials(RCTs) comparing besifloxacin with other treatments or placebo. The primary outcome measures were clinical resolution, rates of bacterial eradication, individual clinical outcomes, cure rates, and bacterial eradication rates of different kinds of pathogens. Safety outcomes were the number of adverse effects(AEs). The final search was performed on August 2018.RESULTS: Eight RCTs were included. Five studies compared the efficacy and safety of besifloxacin with placebo, 2 studies compared besifloxacin with moxifloxacin, and 1 study compared besifloxacin with gatifloxacin. A total of 3105 patients met the inclusion criteria. Besifloxacin presented higher efficacy and safety than did placebo in clinical resolution, rates of bacterial eradication, individual clinical outcomes, cure rates, bacterial eradication rates of different kinds of pathogens and the number of AEs. There was no significant difference between besifloxacin and moxifloxacin or gatifloxacin in the comparison items mentioned above.CONCLUSION: Besifloxacin is highly effective and safe for treatment of acute bacterial conjunctivitis. Further comparative trials regarding the effect of besifloxacin for treatment of acute bacterial conjunctivitis will aid in treatment decisions.展开更多
AIM:To investigate the feasibility and mechanism of immune tolerance in allergic conjunctivitis.METHODS:The allergic conjunctivitis immune tolerance mice model was established by ragweed pollen(RW)and the related cyto...AIM:To investigate the feasibility and mechanism of immune tolerance in allergic conjunctivitis.METHODS:The allergic conjunctivitis immune tolerance mice model was established by ragweed pollen(RW)and the related cytokines were detected.The mice were divided into 9 groups and the maslinic acid(MA)or PBS were given for different group after modeling.The expression levels of chemokine ligand 5(CCL5)and P-65 in the conjunctival tissue were analyzed by immunohistochemistry,quantitative reverse transcription polymerase chain reaction(q RT-PCR)and Western blot.The percentage of interleukin-17(IL-17)and CD4+CD25+in the splenocyte supernatant was analyzed by flow cytometry.Fur thermore,the serum and splenocyte supernatant concentration of total-IgE,interleukin-10(IL-10),and IL-17 was analyzed by enzyme linked immune response(ELISA).RESULTS:After the model was established,symptoms of conjunctivitis were alleviated,the level of P-65,CCL5,IL-17,and total-IgE was raised,while the expression of IL-10,CD4+CD25+was decreased.This result fully demonstrated that a typical IL-17/regulatory-T-cells(Treg cells)imbalance and NF-κB activation.When the NF-κB signal pathway was suppressed,it showed that there was a further relief of conjunctivitis in mice.At the same time,the expression of total-IgE,IL-17,and CCL5 was decreased and the expression of anti-inflammatory factor(IL-10,CD4+CD25+)was increased.CONCLUSION:In the state of immune tolerance,symptoms of conjunctivitis in mice are alleviated,the Th-17 cells of allergic conjunctivitis mice are inhibited,and Treg cells activity is enhanced.展开更多
Taking the hot working die steel (HWDS) 4Cr3Mo2NbVNi as an example, the phase electron structures (PES) and the biphase interface electron structures (BIES) of Mo2C and V4 C3 , which are two kinds of important c...Taking the hot working die steel (HWDS) 4Cr3Mo2NbVNi as an example, the phase electron structures (PES) and the biphase interface electron structures (BIES) of Mo2C and V4 C3 , which are two kinds of important carbides precipitated during tempering in steel were calculated, on the basis of the empirical electron theory of solids and molecules and the improved TFD theory. The influence of Mo2 C and V4 C3 on the mechanical properties of HWDS has been analyzed at electron structure level, and the fundamental reason that the characteristic of the PES and the BIES of carbides decides the behavior of them has been revealed.展开更多
Single-site metal atoms or clusters(SMCs)present high potential to enable the exploration of energetics and kinetics in heterogeneous photocatalysis owing to their unique properties.Here,we report the first work for h...Single-site metal atoms or clusters(SMCs)present high potential to enable the exploration of energetics and kinetics in heterogeneous photocatalysis owing to their unique properties.Here,we report the first work for highly no ligands-protected atomic-level Cu clusters by mediating them in Cd vacancies at the edge of Cd S nanorods(Cu CR SCC)towards photocatalytic CO_(2)conversion.X-ray absorption spectrometric analysis and photoelectric dynamic characterizations demonstrate that the well-defined Cu clusters across the Cd vacancies induce a synergistic effect on CO_(2)reduction through the interfacial conjunction,accelerating charge carrier mobility and facilitating atom utilization.In situ diffuse reflectance infrared Fourier transform spectroscopy,low-coverage calculated isosteric heat,and theoretical studies unveil that the direct cluster/substrate conjunction provides a driving force for interfacial electronic modification and dynamic cooperation.Besides,Cu acts as the active site in the process of CO_(2)photoreduction,which enhances the adsorption and activation of CO_(2).Consequently,this leads to outstanding CO_(2)-to-CO conversion with a turnover number of more than 90 without the addition of any sacrificial agent.Particularly,the Cu clusters-mediated Cd S nanorods are able to serve as carrier provider,allowing the photogenerated electrons transfer from Cd S to Cu clusters.These electrons received from Cd S can further enhance the charge carrier separation and thus achieve high photostability during longtime light irradiation.展开更多
AIM: To evaluate the clinical characteristics of adenoviral keratoconjunctivitis, the management modalities, as well as the incidence of subepithelial corneal infiltrates(SEI).METHODS: Patients with characteristic cli...AIM: To evaluate the clinical characteristics of adenoviral keratoconjunctivitis, the management modalities, as well as the incidence of subepithelial corneal infiltrates(SEI).METHODS: Patients with characteristic clinical symptoms and signs, who presented to our clinic within the first week of symptoms and received the diagnosis of adenoviral keratoconjunctivitis between January 2013 and April 2016, were included in the study. A total of 211 patients were included in the study. Patients were evaluated for the incidence of clinical signs, late complications, management preferences, and the effect of diluted povidone-iodine(d-PVP-I) 2%. RESULTS: Patients’ mean age was 33.03±14.76 y. We observed an increase in the number of cases according to the years. At presentation and/or early follow-up, the clinical signs were conjunctival hyperemia(100%), conjunctival follicules(79.1%), edema of the eyelids(39.3%), chemosis(16.1%), pseudomembrane formation(16.6%), and corneal epitheliopathy(29.9%). During late follow-up 13.3% patients developed conjunctival subepithelial fibrosis, and 39.8% developed SEI. A significant decrease in the incidence of SEI development was observed in patients who used d-PVP-I 2%(P=0.032;33.3% vs 45.9%, respectively in patients who received d-PVP-I 2% and who did not).CONCLUSION: Adenoviral keratoconjunctivitis has a tremendous effect on patient’s comfort and abilities in short-term. Additionally, almost half of the patients develop visual problems related to SEI. According to our clinical experience, using d-PVP-I 2% in the first days of adenoviral keratoconjunctivitis might be helpful in reducing the risk of SEI as a complication.展开更多
Coxsackievirus A24 variant(CVA24v)is a major pathogen that causes continued outbreaks and pandemics of acute hemorrhagic conjunctivitis(AHC).In China,the first confirmed outbreak of CVA24v-related AHC occurred in Beij...Coxsackievirus A24 variant(CVA24v)is a major pathogen that causes continued outbreaks and pandemics of acute hemorrhagic conjunctivitis(AHC).In China,the first confirmed outbreak of CVA24v-related AHC occurred in Beijing in 1988,followed by another two significant outbreaks respectively in 1994 and 2007,which coincides with the three-stage dynamic distribution of AHC in the world after 1970s.To illustrate the genetic characteristics of CVA24v in different periods,a total of 23 strains were isolated from those three outbreaks and the whole genome of those isolations were sequenced and analyzed.Compared with the prototype strain,the 23 strains shared four nucleotide deletions in the 5'UTR except the 0744 strain isolated in 2007.And at the 98th site,one nucleotide insertion was found in all the strains collected from 2007.From 1994 to 2007,amino acid polarity in the VP1 region at the 25th and the 32nd site were changed.Both the 3C and VP1 phylogenetic tree indicated that isolates from 1988 and 1994 belonged to Genotype III(GIII),and 2007 strains to Genotype IV(GIV).According to the Bayesian analysis based on complete genome sequence,the most recent common ancestors for the isolates in1988,1994 and 2007 were respectively estimated around October 1987,February 1993 and December 2004.The evolutionary rate of the CVA24v was estimated to be 7.45×10^(-3) substitutions/site/year.Our study indicated that the early epidemic of CVA24v in Chinese mainland was the GIII.Point mutations and amino acid changes in different genotypes of CVA24v may generate intensity differences of the AHC outbreak.CVA24v has been evolving constantly with a relatively rapid rate.展开更多
The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplane...The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions,and simultaneously monitor the auroral response of the Northern Hemisphere ionosphere.Combining these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE mission.Here,we describe current community efforts to prepare for SMILE,and the benefits and context various experiments that have explicitly expressed support for SMILE can offer.A dedicated group of international scientists representing many different experiment types and geographical locations,the Ground-based and Additional Science Working Group,is facilitating these efforts.Preparations include constructing an online SMILE Data Fusion Facility,the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar,and the consideration of particular observing strategies and spacecraft conjunctions.We anticipate growing interest and community engagement with the SMILE mission,and we welcome novel ideas and insights from the solar-terrestrial community.展开更多
Theempiricalelectrontheory of solidsand molecules( EET) and theimproved TFDtheory wereapplied tocalculatethe phasestructurefactorsand interfaceconjunction factorsofcom mon alloying elementsincastiron. Akind of Si- M...Theempiricalelectrontheory of solidsand molecules( EET) and theimproved TFDtheory wereapplied tocalculatethe phasestructurefactorsand interfaceconjunction factorsofcom mon alloying elementsincastiron. Akind of Si- Mo- Cu ductileiron with rareearth Mg asnodularizer was designed accordingtothese valenceelectron structure parameters. Actual applicationtestsshow thatthelongevity of thisiron is 1.5 timesof thatof high manganesesteel. This accordance of theoretical results and actual effectsshows the composition design methodcan beused in othercastiron research.展开更多
AIM: To evaluate the relative efficacy and safety of besifloxacin for treatment of acute bacterial conjunctivitis. METHODS: A comprehensive search in PubM ed, EMBASE Web of Science, Cochrane Central Database and CNKI ...AIM: To evaluate the relative efficacy and safety of besifloxacin for treatment of acute bacterial conjunctivitis. METHODS: A comprehensive search in PubM ed, EMBASE Web of Science, Cochrane Central Database and CNKI was undertaken for randomized controlled trials(RCTs) comparing besifloxacin with other treatments or placebo. The primary outcome measures were clinical resolution, rates of bacterial eradication, individual clinical outcomes, cure rates, and bacterial eradication rates of different kinds of pathogens. Safety outcomes were the number of adverse effects(AEs). The final search was performed on August 2018. RESULTS: Six RCTs were included. Four studies compared the efficacy and safety of besifloxacin with placebo, 1 study compared besifloxacin with moxifloxacin, and 1 study compared besifloxacin with gatifloxacin. A total of 2780 patients met the inclusion criteria. Besifloxacin presented higher efficacy and safety than did placebo in clinical resolution, rates of bacterial eradication, individual clinical outcomes, cure rates, bacterial eradication rates of different kinds of pathogens and the number of AEs. There was no significant difference between besifloxacin and moxifloxacin or gatifloxacin in the comparison items mentioned above. CONCLUSION: Besifloxacin is highly effective and safe for treatment of acute bacterial conjunctivitis. Further comparative trials regarding the effect of besifloxacin for treatment of acute bacterial conjunctivitis will aid in treatment decisions.展开更多
篇章连贯性(Text-coherence)是篇章语言学研究的重要课题.人们无论说话或写文章,都是根据话题和会话目的把句子通过一定的连接手段有机地结合起来.语言符号组装的线性特征规定了言者只能将语言单位在"时间线条"上进行线性的排...篇章连贯性(Text-coherence)是篇章语言学研究的重要课题.人们无论说话或写文章,都是根据话题和会话目的把句子通过一定的连接手段有机地结合起来.语言符号组装的线性特征规定了言者只能将语言单位在"时间线条"上进行线性的排列,构成言语链.话语中的句子如同这一链条上的环节,彼此都不是孤立的,而是首尾相顾,环环紧扣,体现了表达思想,传递信息的连续性和条理性.构成英语篇章连贯性的因素很多.Halliday在Cohesion in English 一书中把衔接手段分为五大类:照应(reference),替代(substitution),省略(ellipsis),连接词语(conjunction)。展开更多
文摘The present paper carries a corpus-based study on the use of adverbial conjuncts in order to reveal the difference between Chinese EFL learners and native speakers. It is based on two corpora of CLEC and LOB. According to the data-driven analysis, the research shows that Chinese EFL learners tend to overuse listing conjuncts while underuse other categories. This may result from the limitation of writing topics and the lack of cohesion in their writings. Besides, the incomplete understanding of adverbial conjuncts may cause the avoiding of certain conjuncts and thus turning to the easier listing conjuncts for help.
文摘Linking words,also called transition words,are quite useful in English expressions.Linking words are not the same as conjunctions,although some conjunctions can function as linking words.Here's a clear explanation for English learners,followed by a wellorganized passage on the functions of linking words in writing and communication.
基金Supported by the Natural Science Foundation of the Zhejiang Province(No.LGD22H120002).
文摘AIM:To investigate the factors influencing meibomian gland atrophy(MGA)in children with allergic conjunctivitis(AC).METHODS:In this cross-sectional study,60 children with AC aged 6-17y and 20 age-matched children without signs or symptoms of ocular surface dysfunction were included.Information on the duration of AC,untreated time,electronic screen time(EST),outdoor exercise time,body mass index(BMI),and frequency of eye rubbing was collected using a health history form.The Standard Patient Evaluation of Eye Dryness(SPEED)score was used for dry eye assessment.Images of the meibomian glands(MGs)were obtained using Keratograph 5M,and the rate of meibomian gland atrophy(MGAR)was calculated using Image J.All subjects underwent routine eye examinations.RESULTS:The average age of the AC group was 10.43±2.75y(range 6-17y)and 10.35±3.42y(range 6-14y)in the control group.The MGAR in the AC group was 33.42%±11.91%,significantly higher than that in the control group(18.10%±11.74%,P<0.001).Moreover,the MGAR in younger children(aged 12 and below)was significantly higher than in older children(P<0.05).Multi-factor linear regression analysis revealed that EST non-projector was a risk factor for MGAR(β=0.332,95%CI 0.04-0.22,P=0.004),while outdoor exercise time was a protective factor against MGAR(β=-0.407,95%CI-0.39 to-0.10,P=0.001).The untreated time of AC was identified as a risk factor for MGAR(β=0.24,95%CI 0.07-1.98,P=0.037),and the frequency of eye rubbing was associated with MG distortion score(P=0.00).CONCLUSION:Children with AC exhibit exacerbate MGA,with the degree of atrophy worsening as the untreated time of AC prolongs.Children under 12 years old show a higher MGAR,and EST non-projector negatively impacts MGA,while increased outdoor exercise time acts as a protective factor against MGA.
基金supported in part by the Major Science and Technology Projects in Yunnan Province(202202AD080013)King Khalid University for funding this work through Large Group Project under grant number RGP.2/373/45.
文摘Data privacy leakage has always been a critical concern in cloud-based Internet of Things(IoT)systems.Dynamic Symmetric Searchable Encryption(DSSE)with forward and backward privacy aims to address this issue by enabling updates and retrievals of ciphertext on untrusted cloud server while ensuring data privacy.However,previous research on DSSE mostly focused on single keyword search,which limits its practical application in cloud-based IoT systems.Recently,Patranabis(NDSS 2021)[1]proposed a groundbreaking DSSE scheme for conjunctive keyword search.However,this scheme fails to effectively handle deletion operations in certain circumstances,resulting in inaccurate query results.Additionally,the scheme introduces unnecessary search overhead.To overcome these problems,we present CKSE,an efficient conjunctive keyword DSSE scheme.Our scheme improves the oblivious shared computation protocol used in the scheme of Patranabis,thus enabling a more comprehensive deletion functionality.Furthermore,we introduce a state chain structure to reduce the search overhead.Through security analysis and experimental evaluation,we demonstrate that our CKSE achieves more comprehensive deletion functionality while maintaining comparable search performance and security,compared to the oblivious dynamic cross-tags protocol of Patranabis.The combination of comprehensive functionality,high efficiency,and security makes our CKSE an ideal choice for deployment in cloud-based IoT systems.
基金supported by Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2025R899)Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabiasupported by the Deanship of Scientific Research,Vice Presidency for Graduate Studies and Scientific Research,King Faisal University,Saudi Arabia(KFU252831)。
文摘This study investigates the transmission dynamics of conjunctivitis using stochastic delay differential equations(SDDEs).A delayed stochastic model is formulated by dividing the population into five distinct compartments:susceptible,exposed,infected,environmental irritants,and recovered individuals.The model undergoes thorough analytical examination,addressing key dynamical properties including positivity,boundedness,existence,and uniqueness of solutions.Local and global stability around the equilibrium points is studied with respect to the basic reproduction number.The existence of a unique global positive solution for the stochastic delayed model is established.In addition,a stochastic nonstandard finite difference scheme is developed,which is shown to be dynamically consistent and convergent toward the equilibrium states.The scheme preserves the essential qualitative features of the model and demonstrates improved performance when compared to existing numerical methods.Finally,the impact of time delays and stochastic fluctuations on the susceptible and infected populations is analyzed.
文摘Objective To observe the clinical efficacy of bloodletting at Erjian(耳尖EX- HN 6) combined with traditional Chinese herbal medication (heat-clearing I recipe) ultrasonic atomization in treatment of acute catarrhal conjunctivitis (fulminant wind and invading fever). Method One hundred and twenty- two patients (244 eyes) were randomly divided into 3 groups. In group A (40 cases, 80 eyes), levofloxacin hydrochloride eye drops were administrated for four times per day; in group B (42 cases, 84 eyes), "heat-clearing I recipe" ultrasonic atomization was applied for twice per day with 20 rain for each time; and in group C (40 cases, 80 eyes), bloodletting at EX-HN 6 was applied before ultrasonic atomization on the first 3 days of treatment, with once per day. Result (1) The total effective rate of group C was 100.00% which was significantly superior to 88.75% in group A (P〈0.05); (2) the average course of treatment of clinical cured patients of group C was significantly shorter than those of group A and group B (P〈0.05). Conclusion It is indicated from this study that "heat-clearing I recipe" ultrasonic atomization combined with bloodletting at EX-HN 6 in treatment of acute catarrhal conjunctivitis (fulminant wind and invading fever) have definite efficacy, its clinical efficacy is significantly superior to traditional levofloxacin treatment, and its course of treatment is obviously shorter than that of simple traditional Chinese medicine ultrasonic atomization. Cold ultrasonic atomization can effectively relieve local burning sensation, obviously relieve reddening and swelling and heat pain of patients, and ease subjective discomfort and emotional tension of patients.
文摘The effects of BCG PSN on T cell subsets and cytokines in vernal conjunctivitis were observed. The level of total IgE was quantitatively determined before and after treatment with BCG PSN by allergen diagnostic instrument in vitro . The content of T cell subsets of peripheral blood and cytokine were determined by using indirect immune fluorescence method, and IL 4 and INF γ were quantified by ELISA. The results showed that the level of total IgE was substantially reduced ( P <0.01) after treatment in the BCG PSN group. Meanwhile, CD + 8 was decreased, CD + 4 and CD + 4/CD + 8 ratio elevated with significant differences ( P <0.05) as compared with pre treatment results. The changes in total IgE, CD + 8 ,CD + 4 and CD + 4/CD + 8 ratio after treatment also presented significant differences ( P <0.05) between BCG PSN group and routine treatment group. The level of IL 4 in serum declined ( P <0.05) after treatment in the BCG PSN group, and INF γ went up ( P <0 05). IL 4 and INF γ in serum showed significant differences ( P <0.05) between two groups after treatment. It is concluded that BCG PSN has a bi directional immunoregulating effect. It can bring CD + 4 and CD + 8 into homeostasis, thereby preventing the occurrence of anaphylaxis. At the same time, BCG PSN can restrain Th 2, decrease the synthesis of IL 4, switch the balance of Th l/Th 2 to Th 1 side, boost up the predominance of Th 1 relatively, which is propitious to perennial stabilization and recovery of vernal conjunctivitis.
基金A grant-in-aid for Scientific Research from the Japanese Ministry of Education,Culture,Sports,Science and Technology
文摘AIM: To assess the efficacy of topical Semaphorin 3A(SEMA3A) in the treatment of allergic conjunctivitis.METHODS: Experimental allergic conjunctivitis(EAC)mice model induced by short ragweed pollen(SRW) in 4-week-old of BALB/c mice, mice were evaluated using haematoxylin and eosin(H&E) staining, immunofluor-escence and light microscope photographs. Early phase took the samples in 24 h after instillation and late phase took the samples between 4 to 14 d after the start of treatment. The study use of topical SEMA3A(10 U, 100 U,1000 U) eye drops and subconjunctival injection of SEMA3 A with same concentration. For comparison, five types of allergy eyedrops were quantified using clinical characteristics.· RESULTS: Clinical score of composite ocular symptoms of the mice treated with SEMA3 A were significantly decreased both in the immediate phase and the late phase compared to those treated with commercial ophthalmic formulations and non-treatment mice. SEMA3 A treatment attenuates infiltration of eosinophils entering into conjunctiva in EAC mice. The score of eosinophil infiltration in the conjunctiva of SEMA3 A 1000 U-treated group were significantly lower than low-concentration of SEMA3 A treated groups and non-treated group. SEMA3 A treatment also suppressed T-cell proliferation in vitro and decreased serum total Ig E levels in EAC mice. Moreover, treatment of SEMA3 A suppressed Th2-related cytokines(IL-5, IL-13 and IL-4)and pro-inflammatory cytokines(IFN-γ, IL-17 and TNF-α)release, but increased regulatory cytokine IL-10 concentration in the conjunctiva of EAC mice.CONCLUSION: SEMA3 A as a biological agent, showed the beneficial activity in ocular allergic processes with the less damage to the intraocular tissue. It is expected that SEMA3 A may be contributed in patients with a more severe spectrum of refractory ocular allergic diseases including allergic conjunctivitis in the near future.
文摘AIM: To demonstrate the effects of two different types of allergic conjunctivitis on severity of keratoconus (KC). ·METHODS: We retrospectively reviewed the medical records of 171 KC patients referred between June 2010 and June 2011. The KC patients were divided into 3 groups as KC (group A), KC with vernal keratoconjunctivitis (VKC) (group B) and KC with allergic conjunctivitis (AC) (group C). Main outcome measures were demographic and ocular clinical features including age at presentation, gender, spherical equivalent (SE), best spectacle corrected visual acuity (BCVA), mean keratometric measurement (Km), central corneal thickness (CCT), and intraocular pressure (IOP). Groups were compared in term of study variables. · RESULTS: The median age at presentation was significantly lower in group B (P 【0.001). According to the median SE (P =0.003), BCVA(P =0.022), Km(P 【0.001), CCT (P =0.015) and Amsler-Krumeich classification (P 【 0.001), KC was more severe in group B. There was no significant difference in terms of IOP and corrected IOP among the groups (P =0.44), however there were 4 patients who had increased corrected IOP developed after topical corticosteroid use in group B. The differences among the groups persisted even after controlling for age and gender. · CONCLUSION: Our findings demonstrated a more severe KC in VKC patients despite their younger age which suggests evaluation of VKC patients as a separate group in keratoconus disease.
文摘AIM: To evaluate the relative efficacy and safety of besifloxacin for treatment of acute bacterial conjunctivitis.METHODS: A comprehensive search in PubMed, EMBASE Web of Science, Cochrane Central Database and CNKI was undertaken for randomized controlled trials(RCTs) comparing besifloxacin with other treatments or placebo. The primary outcome measures were clinical resolution, rates of bacterial eradication, individual clinical outcomes, cure rates, and bacterial eradication rates of different kinds of pathogens. Safety outcomes were the number of adverse effects(AEs). The final search was performed on August 2018.RESULTS: Eight RCTs were included. Five studies compared the efficacy and safety of besifloxacin with placebo, 2 studies compared besifloxacin with moxifloxacin, and 1 study compared besifloxacin with gatifloxacin. A total of 3105 patients met the inclusion criteria. Besifloxacin presented higher efficacy and safety than did placebo in clinical resolution, rates of bacterial eradication, individual clinical outcomes, cure rates, bacterial eradication rates of different kinds of pathogens and the number of AEs. There was no significant difference between besifloxacin and moxifloxacin or gatifloxacin in the comparison items mentioned above.CONCLUSION: Besifloxacin is highly effective and safe for treatment of acute bacterial conjunctivitis. Further comparative trials regarding the effect of besifloxacin for treatment of acute bacterial conjunctivitis will aid in treatment decisions.
基金Supported by the Provincial Innovation Team for Cataract and Ocular Fundus Disease in the Second People’s Hospital of Yunnan Province(No.2017HC010)the Key Laboratory of Yunnan Province for the Prevention and Treatment of Ophthalmology(No.2017DG008)Expert Workstation of Yao Ke(No.2017IC064)。
文摘AIM:To investigate the feasibility and mechanism of immune tolerance in allergic conjunctivitis.METHODS:The allergic conjunctivitis immune tolerance mice model was established by ragweed pollen(RW)and the related cytokines were detected.The mice were divided into 9 groups and the maslinic acid(MA)or PBS were given for different group after modeling.The expression levels of chemokine ligand 5(CCL5)and P-65 in the conjunctival tissue were analyzed by immunohistochemistry,quantitative reverse transcription polymerase chain reaction(q RT-PCR)and Western blot.The percentage of interleukin-17(IL-17)and CD4+CD25+in the splenocyte supernatant was analyzed by flow cytometry.Fur thermore,the serum and splenocyte supernatant concentration of total-IgE,interleukin-10(IL-10),and IL-17 was analyzed by enzyme linked immune response(ELISA).RESULTS:After the model was established,symptoms of conjunctivitis were alleviated,the level of P-65,CCL5,IL-17,and total-IgE was raised,while the expression of IL-10,CD4+CD25+was decreased.This result fully demonstrated that a typical IL-17/regulatory-T-cells(Treg cells)imbalance and NF-κB activation.When the NF-κB signal pathway was suppressed,it showed that there was a further relief of conjunctivitis in mice.At the same time,the expression of total-IgE,IL-17,and CCL5 was decreased and the expression of anti-inflammatory factor(IL-10,CD4+CD25+)was increased.CONCLUSION:In the state of immune tolerance,symptoms of conjunctivitis in mice are alleviated,the Th-17 cells of allergic conjunctivitis mice are inhibited,and Treg cells activity is enhanced.
基金ItemSponsored by National Natural Science Foundation of China (50271030) Provincial Natural Science Foundation ofLiaoning Province of China (972072)
文摘Taking the hot working die steel (HWDS) 4Cr3Mo2NbVNi as an example, the phase electron structures (PES) and the biphase interface electron structures (BIES) of Mo2C and V4 C3 , which are two kinds of important carbides precipitated during tempering in steel were calculated, on the basis of the empirical electron theory of solids and molecules and the improved TFD theory. The influence of Mo2 C and V4 C3 on the mechanical properties of HWDS has been analyzed at electron structure level, and the fundamental reason that the characteristic of the PES and the BIES of carbides decides the behavior of them has been revealed.
基金supported by the National Natural Science Foundation of China(Nos.51672099 and 52073263)the Sichuan Science and Technology Program under(No.2021JDTD0026)the Fundamental Research Funds for the Central Universities(Nos.2017-QR-25 and ZYGX2019J031)。
文摘Single-site metal atoms or clusters(SMCs)present high potential to enable the exploration of energetics and kinetics in heterogeneous photocatalysis owing to their unique properties.Here,we report the first work for highly no ligands-protected atomic-level Cu clusters by mediating them in Cd vacancies at the edge of Cd S nanorods(Cu CR SCC)towards photocatalytic CO_(2)conversion.X-ray absorption spectrometric analysis and photoelectric dynamic characterizations demonstrate that the well-defined Cu clusters across the Cd vacancies induce a synergistic effect on CO_(2)reduction through the interfacial conjunction,accelerating charge carrier mobility and facilitating atom utilization.In situ diffuse reflectance infrared Fourier transform spectroscopy,low-coverage calculated isosteric heat,and theoretical studies unveil that the direct cluster/substrate conjunction provides a driving force for interfacial electronic modification and dynamic cooperation.Besides,Cu acts as the active site in the process of CO_(2)photoreduction,which enhances the adsorption and activation of CO_(2).Consequently,this leads to outstanding CO_(2)-to-CO conversion with a turnover number of more than 90 without the addition of any sacrificial agent.Particularly,the Cu clusters-mediated Cd S nanorods are able to serve as carrier provider,allowing the photogenerated electrons transfer from Cd S to Cu clusters.These electrons received from Cd S can further enhance the charge carrier separation and thus achieve high photostability during longtime light irradiation.
文摘AIM: To evaluate the clinical characteristics of adenoviral keratoconjunctivitis, the management modalities, as well as the incidence of subepithelial corneal infiltrates(SEI).METHODS: Patients with characteristic clinical symptoms and signs, who presented to our clinic within the first week of symptoms and received the diagnosis of adenoviral keratoconjunctivitis between January 2013 and April 2016, were included in the study. A total of 211 patients were included in the study. Patients were evaluated for the incidence of clinical signs, late complications, management preferences, and the effect of diluted povidone-iodine(d-PVP-I) 2%. RESULTS: Patients’ mean age was 33.03±14.76 y. We observed an increase in the number of cases according to the years. At presentation and/or early follow-up, the clinical signs were conjunctival hyperemia(100%), conjunctival follicules(79.1%), edema of the eyelids(39.3%), chemosis(16.1%), pseudomembrane formation(16.6%), and corneal epitheliopathy(29.9%). During late follow-up 13.3% patients developed conjunctival subepithelial fibrosis, and 39.8% developed SEI. A significant decrease in the incidence of SEI development was observed in patients who used d-PVP-I 2%(P=0.032;33.3% vs 45.9%, respectively in patients who received d-PVP-I 2% and who did not).CONCLUSION: Adenoviral keratoconjunctivitis has a tremendous effect on patient’s comfort and abilities in short-term. Additionally, almost half of the patients develop visual problems related to SEI. According to our clinical experience, using d-PVP-I 2% in the first days of adenoviral keratoconjunctivitis might be helpful in reducing the risk of SEI as a complication.
基金funded by the National Science and Technology Major project of China(Project No.2017ZX10104001)the National key research and development project(Project No.2021YFC0863000)the Beijing Natural Science Foundation(Project No.L192014)。
文摘Coxsackievirus A24 variant(CVA24v)is a major pathogen that causes continued outbreaks and pandemics of acute hemorrhagic conjunctivitis(AHC).In China,the first confirmed outbreak of CVA24v-related AHC occurred in Beijing in 1988,followed by another two significant outbreaks respectively in 1994 and 2007,which coincides with the three-stage dynamic distribution of AHC in the world after 1970s.To illustrate the genetic characteristics of CVA24v in different periods,a total of 23 strains were isolated from those three outbreaks and the whole genome of those isolations were sequenced and analyzed.Compared with the prototype strain,the 23 strains shared four nucleotide deletions in the 5'UTR except the 0744 strain isolated in 2007.And at the 98th site,one nucleotide insertion was found in all the strains collected from 2007.From 1994 to 2007,amino acid polarity in the VP1 region at the 25th and the 32nd site were changed.Both the 3C and VP1 phylogenetic tree indicated that isolates from 1988 and 1994 belonged to Genotype III(GIII),and 2007 strains to Genotype IV(GIV).According to the Bayesian analysis based on complete genome sequence,the most recent common ancestors for the isolates in1988,1994 and 2007 were respectively estimated around October 1987,February 1993 and December 2004.The evolutionary rate of the CVA24v was estimated to be 7.45×10^(-3) substitutions/site/year.Our study indicated that the early epidemic of CVA24v in Chinese mainland was the GIII.Point mutations and amino acid changes in different genotypes of CVA24v may generate intensity differences of the AHC outbreak.CVA24v has been evolving constantly with a relatively rapid rate.
基金supported by Royal Society grant DHFR1211068funded by UKSA+14 种基金STFCSTFC grant ST/M001083/1funded by STFC grant ST/W00089X/1supported by NERC grant NE/W003309/1(E3d)funded by NERC grant NE/V000748/1support from NERC grants NE/V015133/1,NE/R016038/1(BAS magnetometers),and grants NE/R01700X/1 and NE/R015848/1(EISCAT)supported by NERC grant NE/T000937/1NSFC grants 42174208 and 41821003supported by the Research Council of Norway grant 223252PRODEX arrangement 4000123238 from the European Space Agencysupport of the AUTUMN East-West magnetometer network by the Canadian Space Agencysupported by NASA’s Heliophysics U.S.Participating Investigator Programsupport from grant NSF AGS 2027210supported by grant Dnr:2020-00106 from the Swedish National Space Agencysupported by the German Research Foundation(DFG)under number KR 4375/2-1 within SPP"Dynamic Earth"。
文摘The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions,and simultaneously monitor the auroral response of the Northern Hemisphere ionosphere.Combining these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE mission.Here,we describe current community efforts to prepare for SMILE,and the benefits and context various experiments that have explicitly expressed support for SMILE can offer.A dedicated group of international scientists representing many different experiment types and geographical locations,the Ground-based and Additional Science Working Group,is facilitating these efforts.Preparations include constructing an online SMILE Data Fusion Facility,the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar,and the consideration of particular observing strategies and spacecraft conjunctions.We anticipate growing interest and community engagement with the SMILE mission,and we welcome novel ideas and insights from the solar-terrestrial community.
文摘Theempiricalelectrontheory of solidsand molecules( EET) and theimproved TFDtheory wereapplied tocalculatethe phasestructurefactorsand interfaceconjunction factorsofcom mon alloying elementsincastiron. Akind of Si- Mo- Cu ductileiron with rareearth Mg asnodularizer was designed accordingtothese valenceelectron structure parameters. Actual applicationtestsshow thatthelongevity of thisiron is 1.5 timesof thatof high manganesesteel. This accordance of theoretical results and actual effectsshows the composition design methodcan beused in othercastiron research.
文摘AIM: To evaluate the relative efficacy and safety of besifloxacin for treatment of acute bacterial conjunctivitis. METHODS: A comprehensive search in PubM ed, EMBASE Web of Science, Cochrane Central Database and CNKI was undertaken for randomized controlled trials(RCTs) comparing besifloxacin with other treatments or placebo. The primary outcome measures were clinical resolution, rates of bacterial eradication, individual clinical outcomes, cure rates, and bacterial eradication rates of different kinds of pathogens. Safety outcomes were the number of adverse effects(AEs). The final search was performed on August 2018. RESULTS: Six RCTs were included. Four studies compared the efficacy and safety of besifloxacin with placebo, 1 study compared besifloxacin with moxifloxacin, and 1 study compared besifloxacin with gatifloxacin. A total of 2780 patients met the inclusion criteria. Besifloxacin presented higher efficacy and safety than did placebo in clinical resolution, rates of bacterial eradication, individual clinical outcomes, cure rates, bacterial eradication rates of different kinds of pathogens and the number of AEs. There was no significant difference between besifloxacin and moxifloxacin or gatifloxacin in the comparison items mentioned above. CONCLUSION: Besifloxacin is highly effective and safe for treatment of acute bacterial conjunctivitis. Further comparative trials regarding the effect of besifloxacin for treatment of acute bacterial conjunctivitis will aid in treatment decisions.
文摘篇章连贯性(Text-coherence)是篇章语言学研究的重要课题.人们无论说话或写文章,都是根据话题和会话目的把句子通过一定的连接手段有机地结合起来.语言符号组装的线性特征规定了言者只能将语言单位在"时间线条"上进行线性的排列,构成言语链.话语中的句子如同这一链条上的环节,彼此都不是孤立的,而是首尾相顾,环环紧扣,体现了表达思想,传递信息的连续性和条理性.构成英语篇章连贯性的因素很多.Halliday在Cohesion in English 一书中把衔接手段分为五大类:照应(reference),替代(substitution),省略(ellipsis),连接词语(conjunction)。