OBJECTIVE: To assess the diagnostic value of endoscopic pancreatic duct brushing in detecting mutation of the K-ras gene at codon 12 in cytologic specimens from patients with pancreatic cancer. METHODS: Thirty-five pa...OBJECTIVE: To assess the diagnostic value of endoscopic pancreatic duct brushing in detecting mutation of the K-ras gene at codon 12 in cytologic specimens from patients with pancreatic cancer. METHODS: Thirty-five patients treated at Changhai Hospital, Shanghai between 1999 and 2001 were enrolled. Their cells obtained by pancreatic duct brushing during endoscopic retrograde tholangiopancreatography (ERCP) were suspended with phosphate buffer solution (PBS). DNA of the cells was extracted and mutation of the K-ras gene at codon 12 detected by means of PCR-SSCP. RESULTS: The K-ras gene mutation rate of pancreatic cancer was 70%, which was higher than that of chronic pancreatitis (14%, P<0.05). K-ras gene mutation was not found in patients with pancreatic cystorcarcinoma and duodenum carcinoma. As to the location of pancreatic cancer, no significant difference was observed between the head, the body and tail. The sensitivity, specificity, accuracy of pancreatic duct brushing in detecting pancreatic cancer was 70%, 94%, and 83%, respectively. CONCLUSION: K-ras analysis of pancreatic brushing samples is helpful in the diagnosis of patients with early pancreatic cancer.展开更多
Preoperative cytologic brushing and biopsy under direct Vision withfiberoptic colonoscopy(FC)and postoperative histopathologic examination wereperformed in 147 patients who were suspected of suffering from carcinoma o...Preoperative cytologic brushing and biopsy under direct Vision withfiberoptic colonoscopy(FC)and postoperative histopathologic examination wereperformed in 147 patients who were suspected of suffering from carcinoma of co-lon.In FC cytologic brushing,128 cases were positive for malignancy(87.1percent),18 false-negative(12.2 percent)and only one false-positive(0.7 percent).In the 146 FC biopsy specimens,124 were positive for malignancy(84 4 percent)and 22 false-negative and no false-positive.Combination of FC cytologic brushingwith FC biopsy could raise the diagnostic rate of colonic carcinoma to 95.2% anddecrease false-negative and false-positive because the two methods may replenisheach other in sampling and observation.Cytologic brushing is most valuable tothe early diagnosis of colonic carcinoma.When colonic stricture and obstructionprevent the colonoscope from reaching the lesion and FC biopsy cannot bedone,FC cytologic brushing is an effective method for diagnosis.The positiverate and false-negative rate of the cytologic brushing did not correlate to grosstyping,histopathologic typing and Dukes staging(P】0.05).The factorsinfluencing the correct diagnosis of colonic carcinoma by FC cytologic brushingare discussed in this paper.展开更多
The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture base resins were compared. Acrylic denture base resins （auto-polymerizing, heat-polymerizing, ...The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture base resins were compared. Acrylic denture base resins （auto-polymerizing, heat-polymerizing, injected heat-polymerizing resins） were examined after a tungsten carbide bur, and after chairside polishing using 3 polishing kits and pumice. The specimens were subjected to mechanical brushing using a wear tester to simulate 30 000 strokes of brushing. The surface roughness of the acrylic denture base resin specimens was measured using a contact pro-filometer. After the test, the random polished acrylic resins were evaluated by scanning electron mi-croscopy （SEM） and atomic force microscopy （AFM）. Acrylic denture base resins polished using the 3 types of polishing kits had a smoother surface than those finished with the tungsten carbide bur （p〈0.05）. The surface of the resin polished by a TC cutter exceeded the Ra of 0.2 μm （p〈0.05）. The auto-polymerizing resin showed a significantly higher surface roughness than the heat-polymerizing resin and injected heat-polymerizing resin （p〉0.05）. In the case of polishing step wise, there was almost no change in surface roughness after brushing （p〉0.05）.展开更多
Introduction and Objective: The aim of this research was to find out the interaction of anthropometric measurements particularly body mass and oral health status of Turkish young adult nationals regionally, depending ...Introduction and Objective: The aim of this research was to find out the interaction of anthropometric measurements particularly body mass and oral health status of Turkish young adult nationals regionally, depending on the effects of diet (food and fluid consumption), smoking and tooth brushing habits, which were determined by using the body mass index (BMI) and dental health index (DMFT). Material and Methods: The BMI and DMFT of 202 cases, with an age average 22.5 years, were recorded through physical and clinical examinations. Statistical evaluation of the data was checked by Cronbach’s Alpha Reliability Scale and performed by analysis of variance, Somer’s d and Pearson Chi-Square statistics, Poisson Regression and Odds Ratio analysis. Results: The results showed that the mean of BMI was at the optimum level (21.52) for all cases. The DMFT was higher for underweight females and for overweight males. The mean of DMFT according to sexes seemingly had no significant difference;however, females had 8.6% more DMFT than males. When the risk factors of dental caries were evaluated, the DMFT was found as 19.3% more for cases consuming high carbohydrate foods, 4.5% more for high beverage consumption and 18% more for smokers. Conclusions: In conclusion, tooth brushing 3 or more times a day is necessary to decrease the DMFT and tooth brushing 3 times a day as opposed to 1 or 2 times shows significant difference regarding oral health.展开更多
Background:Tissue specimens for nasopharyngeal carcinoma(NPC)research are scarce because of sampling dif-ficulties.Previous studies have suggested non-invasive nasopharyngeal brushing as an effective sampling method f...Background:Tissue specimens for nasopharyngeal carcinoma(NPC)research are scarce because of sampling dif-ficulties.Previous studies have suggested non-invasive nasopharyngeal brushing as an effective sampling method for NPC diagnosis.The present study aimed to evaluate the feasibility of nasopharyngeal brushing in the acquisition of NPC nucleic acids for research.Methods:Nasopharyngeal brushing samples were acquired from 24 healthy individuals and 48 NPC patients.Tissues from 48 NPC and 18 nasopharyngitis patients were collected by endoscopic biopsy.The expression levels of tumor suppressor genes(TSGs)and Epstein-Barr virus(EBV)-encoded microRNAs as well as EBV DNA copy number were measured by quantitative polymerase chain reaction in both types of samples.Results:Among six TSGs examined,the expression levels of two genes were significantly decreased in nasopharyn-geal brushing and tissue samples from NPC patients as compared with those from healthy/nasopharyngitis indi-viduals.Four EBV-encoded microRNAs,mir-bart1-5p,mir-bart5,mir-bart6-5p,and mir-bart17-5p,were significantly up-regulated in both NPC brushing and tissue samples compared with those from healthy/nasopharyngitis controls(P<0.001).EBV DNA was significantly increased in both nasopharyngeal brushing samples(P<0.001)and tissue sam-ples(P<0.001)from NPC patients in comparison with those from healthy controls.Conclusions:Nasopharyngeal brushing can obtain sufficient tumoral materials for the analysis of viral nucleic acid,including EBV-encoded microRNAs and EBV DNA.For the detection of TSG expression,nasopharyngeal brushings was feasible but inferior to tissue samples.This study confirms nasopharyngeal brushing as an applicable sampling method that can aid in nucleic acid-based NPC research.展开更多
A polarization-sensitive and flexible photodetector was fabricated through the precise alignment of perovskite nanowires(NWs)using a brush coating technique.The alignment of the NWs was meticulously examined,consideri...A polarization-sensitive and flexible photodetector was fabricated through the precise alignment of perovskite nanowires(NWs)using a brush coating technique.The alignment of the NWs was meticulously examined,considering various chemical properties of the solvent,such as boiling point,viscosity,and surface tension.Notably,when the NWs were brush-coated with toluene dispersion,the NWs were aligned in higher order than those processed from octane dispersion.The degree of alignment was correlated with the photodetector property.Especially,the well-aligned NW photodetector exhibited a two-fold disparity in current response contingent on the polarization direction.Furthermore,even after enduring 500 bending cycles,the device retained 80%of its photodetector performance.This approach underscores the potential of solution-processed flexible photodetectors for advanced optical applications under dynamic operating conditions.展开更多
Hello,everyone!I am Cici.I had a summer holiday that was both busy and happy.From July 11th to July 20th,I went to school every day to learn traditional Chinese painting.The soft brushes glided across the paper,creati...Hello,everyone!I am Cici.I had a summer holiday that was both busy and happy.From July 11th to July 20th,I went to school every day to learn traditional Chinese painting.The soft brushes glided across the paper,creating beautiful and vivid images.展开更多
一、阅读理解[核心素养·文化意识](2024·贵州铜仁一模) The brush pen, one of the “Four Treasures of the Study”, was invented thou-sands of years ago. However, the oldest pen was just a stick or a piece of bamb...一、阅读理解[核心素养·文化意识](2024·贵州铜仁一模) The brush pen, one of the “Four Treasures of the Study”, was invented thou-sands of years ago. However, the oldest pen was just a stick or a piece of bamboo. It was difficult for people to write well on thin silk.展开更多
Amphiphilic asymmetric brush copolymers(AABCs)possess unique self-assembly behaviors owing to their asymmetric brush architecture and multiple functionalities of multicomponent side chains.However,the synthesis of AAB...Amphiphilic asymmetric brush copolymers(AABCs)possess unique self-assembly behaviors owing to their asymmetric brush architecture and multiple functionalities of multicomponent side chains.However,the synthesis of AABCs presents challenges,which greatly limits the exploration of their self-assembly behaviors.In this work,we employed dissipative particle dynamics(DPD)simulations to investigate the self-assembly behaviors of AABCs in selective solution.By varying the copolymer concentration and structure,we conducted the self-assembly phase diagrams of AABCs,revealing complex morphologies such as channelized micelles with one or more solvophilic channels.Moreover,the number,surface area,and one-dimensional density distribution of the channelized micelles were calculated to demonstrate the internal structure and morphological transformation during the self-assembly process.Our findings indicate that the morphology of the internal solvophilic channels is greatly influenced by the copolymer structure,concentration,and interaction parameters between the different side chains.The simulation results are consistent with available experimental observations,which can offer theoretical insights into the self-assembly of AABCs.展开更多
人类对人体奥秘的探索与了解尚处初级阶段。本文提出的一个问题就让我们感到新奇与愕然。洁齿与口腔卫生有助于抑制糖尿病: Gum(齿龈)disease may even be more important than obesity or age as a factorin the onset of diabetes in ...人类对人体奥秘的探索与了解尚处初级阶段。本文提出的一个问题就让我们感到新奇与愕然。洁齿与口腔卫生有助于抑制糖尿病: Gum(齿龈)disease may even be more important than obesity or age as a factorin the onset of diabetes in adults。 上句可译:就诱发成年人糖尿病的因素而言,齿龈疾病也许比肥胖和年龄这两个因素更为重要。 因此,我们有必要认识:the importance of prevention and early treatment ofgum disease in people who are at risk of developing diabetes。 本文对inflammation([医]炎症,发炎)提出了一个颇有原创性的观点:…heart disease has a substantial inflammatory component。】展开更多
What damage can be done to teeth by over-brushing?The enamel of the teeth ran he worn out;the gum can he hurt by over-brushing.And your teeth will feel sensitive if the enamel gets thinner and/or the gum recedes.How o...What damage can be done to teeth by over-brushing?The enamel of the teeth ran he worn out;the gum can he hurt by over-brushing.And your teeth will feel sensitive if the enamel gets thinner and/or the gum recedes.How often should we be brushing our teeth?Two to three rimes a day.What is the recommended amount of time people should spend brushing their teeth?展开更多
Titanium dioxide(TiO_(2))hollow nanoparticles present significant potential for photocatalytic applications while their straightforward preparation with precise structure control is still challenging.This work reports...Titanium dioxide(TiO_(2))hollow nanoparticles present significant potential for photocatalytic applications while their straightforward preparation with precise structure control is still challenging.This work reports the approach to preparing tunable hollow TiO_(2) nanospheres by utilization of spherical polyelectrolyte brushes(SPB)as nanoreactors and templates.During the preparation,the evolution of the structure was characterized by small angle X-ray scattering(SAXS),and in combination with dynamic light scattering and transmission electron microscopy.The formation of TiO_(2) shell within the brush(SPB@TiO_(2))is confirmed by the significant increase of the electron density,and its internal structure has been analyzed by fitting SAXS data,which can be influenced by Titanium precursors and ammonia concentration.After calcining SPB@TiO_(2) in a muffle furnace,hollow TiO_(2) nanospheres are produced,and their transition to the anatase crystal form is triggered,as confirmed by X-ray diffraction analysis.Utilizing the advantages of their hollow structure,these TiO_(2) nanospheres exhibit exceptional catalytic degradation efficiency of methylene blue(MB),tetracycline(TC),and 2,4-dichlorophenoxyacetic acid(2,4-D),and also demonstrate excellent recyclability.展开更多
Confronting the severe health threats and environmental impacts of Cr(Ⅵ) in aquatic environments demands innovative and effective remediation approaches. In this study, Graphene oxide(GO)-decorated poly(dimethyl amin...Confronting the severe health threats and environmental impacts of Cr(Ⅵ) in aquatic environments demands innovative and effective remediation approaches. In this study, Graphene oxide(GO)-decorated poly(dimethyl amino ethyl methacrylate)(PDMAEMA) brush nanocomposites(GOP1, GOP2, GOP3, and GOP4) were fabricated using atom transfer radical polymerization(ATRP) by the “graft from” method.The resulting nanocomposites were utilized for removing Cr(Ⅵ) with good adsorption performance due to the electrostatic interaction of protonated nitrogen groups in the brush chains with negatively charged particles in the solution. The kinetic model of pseudo-second-order best represented the contaminants' adsorption characteristics. The Weber-Morris model further indicated that surface adsorption and intraparticle diffusion mechanisms primarily controlled the adsorption procedure. Additionally, the Langmuir and Temkin isotherm models were found to most accurately represent the adsorption characteristics of the pollutants on the nanocomposites, and GOP4 can achieve the maximum adsorption capacity of 164.4 mg·g^(-1). The adsorbents' capacity maintains above 85% after five cycles of adsorption-desorption. The nanocomposites in this study demonstrate promising potential for eliminating Cr(Ⅵ) from aqueous solutions.展开更多
The aim of this study was to develop self-healable and robust elect roconductive film based on polyaniline copolymer for application as electrode in flexible supercapacitor.For this purpose,the electroconductive polym...The aim of this study was to develop self-healable and robust elect roconductive film based on polyaniline copolymer for application as electrode in flexible supercapacitor.For this purpose,the electroconductive polymer brushes(EPB)was elaborated.The synthesis of EPB is based on graft polymerizations of acrylamide(AAm)on poly(vinyl alcohol)(PVA)with formation of PVA-PAAm polymer brush and subsequent graft copolymerization of aniline and p-phenylenediamine on PVA-PAAm resulting in formation of EPB with electroconducting copoly(aniline-co-pphenylenediamine)(PAPh DA).It was found that the ratio between PVA and PAAm at the first stage greatly influence the electrochemical performance of the EPBs.Electroconducting films were prepared by casting of EPB solution with subsequent drying.Investigation of electrical current distribution through the film with AFM reveal more uniform distribution of PAPhDA in EPB in comparison with reference PVA-PAPhDA and PAAm-PAPhDA samples.It was demonstrated that mechanical cha racteristics and electrical conductivity values of films restore at large extent after curring and self-healing under optimal relative humidity level(58%).The flexile supercapacitor cell with EPB film electrodes demon strate specific capacitance 602 mF·cm^(-2)at the current density of 1 mA·cm^(-2)and retention 94%of initial capacitance after 5000 charge/discharge cycles.展开更多
We present the results of molecular dynamics simulations of steady shear between a pair of neutral polymer brushes,as well as a pair of charged polymer brushes in the strongly compressed regime.The results of the mole...We present the results of molecular dynamics simulations of steady shear between a pair of neutral polymer brushes,as well as a pair of charged polymer brushes in the strongly compressed regime.The results of the molecular dynamic simulations of neutral and polyelectrolyte brushes in implicit solvent including normal forces,shear forces,viscosities and friction coefficients as a function of separation between brushes,are presented in the study.The comparison of the simulation results of neutral and charged brushes shows that the charged brushes is in the quasi-neutral regime,and the dependence of viscosity on the separation distance show the similar power law of neutral brushes.Our simulation results confirm that the implicit solvent simulations of polyelectrolyte brushes that ignore hydrodynamics interaction are in agreement with the scaling predictions qualitatively because of screening of hydrodynamic interaction and long-range electrostatic interactions on the correlation length scale.Both of neutral and charged brushes show the lubrication properties that the friction coefficient decreases with the separation decreases at enough large loads.However,a maximum of friction coefficients is observed for polyelectrolyte brushes,which is in contrast to the neutral brushes with monotonical dependence.展开更多
The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to...The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to the charged groups of polyelectrolyte chains and act as hydrogen bond donors or acceptors to form hydrogen bonds with the hydrogen bond sites associated with polyelectrolyte chains simultaneously.A large number of literatures illustrate that strong polyelectrolytes(SPs)are insensitive to pH,which severely limmits the applications of SPs as smart materials.However,our studies have demonstrated that the CMHB makes SPs pH-responsive.This perspective discusses the mechanism of pH responsiveness of SPs and the pH-tunable properties of SPs,based on the pH-controlled CMHB effect.The future research directions on the pH responsiveness of SPs are also discussed here.It is anticipated that the study of the pH responsiveness of SPs not only will provide a new understanding of the fundamental properties of SPs,but also will greatly expand the applications of SPs in the field of smart materials.展开更多
Polyelectrolyte brushes(PEBs)are commonly used to modify surface that have attracted great research interest.The dielectric permittivity of the grafted surface is typically significantly different from that of solutio...Polyelectrolyte brushes(PEBs)are commonly used to modify surface that have attracted great research interest.The dielectric permittivity of the grafted surface is typically significantly different from that of solution,which results in surface polarization(SP)effect with a jump of electric field.It is thus important to study how SP alters the PEB’s structure and properties.In this work,the SP effects on PEB structure was studied using a statistical thermodynamic theory.The free energy functional to describe SP effect was constructed by using the image-charge method.Meanwhile,the electrostatic potential was solved from a modified Poisson-Boltzmann equation taking the ion solvation effect into consideration.In the absence of SP,the thickness of PEB exhibited a continuous collapse transition when decreasing the solvent quality.In the presence of SP,the collapse became a jump-like transition.Free energy analysis showed that the long-range Coulombic interaction dominated the transition because of the enhanced counterion condensation in the presence of SP.The theory provides an effective tool to study SP effect on PEBs,and the results explain the underlying physics in PEB collapse transition.展开更多
Polyelectrolyte solutions are more variable than uncharged macromolecule due to electrical interaction between charged molecules and surrounding counterions.Therefore,the subject of polyelectrolyte solutions has attra...Polyelectrolyte solutions are more variable than uncharged macromolecule due to electrical interaction between charged molecules and surrounding counterions.Therefore,the subject of polyelectrolyte solutions has attracted a wide range of interests in both basic and applied research,and has also been extensively explored.However,the understanding of the molecular dynamics and conformation of polyelectrolytes in solution remains to be deepened,and universal consensus on some key issues have not been reached.Many methods have contributed to solving the above problems in different ways,including dielectric relaxation spectroscopy(DRS).In this perspective,we briefly reviewed the history of dielectric spectroscopic research on polyelectrolyte solution,with emphasis on summarizing our efforts.In particular,we expound the characteristics of DRS and its ability to obtain the internal information of the system of interest.Finally,we evaluate the advantages and limitations of the dielectric method and discussed future prospects of this field.展开更多
Herein,binary mixed brushes consisting of poly(2-methyl-2-oxazoline)(PMOXA)and poly(2-(dimethylamine)ethyl methacrylate)(PDMAEMA)with different chain lengths were fabricated by successive grafting of NH_(2)-terminated...Herein,binary mixed brushes consisting of poly(2-methyl-2-oxazoline)(PMOXA)and poly(2-(dimethylamine)ethyl methacrylate)(PDMAEMA)with different chain lengths were fabricated by successive grafting of NH_(2)-terminated PMOXA and SH-terminated PDMAEMA onto polydopamine-anchored substrates.The mixed-brush coating was characterized by variable-angle spectroscopic ellipsometry,X-ray photoelectron spectroscopy,Fourier transform infrared spectroscopy,zeta potential measurements,water contact angle,and atomic force microscopy.The mixed brushes showed tunable surface charge,wettability,and surface roughness,depending on the degree of PDMAEMA swelling under varying pH and ionic strength(Ⅰ).Then the adsorption behaviors of pepsin,bovine serum albumin(BSA),γ-globulin,and lysozyme,four very different proteins with regard to isoelectric point,on the mixed brushes coating were studied by using fluorescence microscopy and surface plasmon resonance.When the chain length of PDMAEMA was about twice as long as PMOXA,the mixed brushes not only had high adsorption capacity for pepsin,BSA,and y-globulin but also had a desorption efficiency of 86.9%,87.1%,and 93.5%,respectively.It is explained that electrostatic attraction between the protonated PDMAEMA and positively charged acidic proteins(pepsin and BSA,whose isoelectric points were below the pK_(a) of PDMAEMA)would drive the intensive adsorption(at pH 3,I=10^(-3)mol·L^(-1)for pepsin,and pH 5,I=10^(-5)mol·L^(-1)for BSA),while desorption was dominated by the hydrophilic PMOXA when PDMAEMA was shrinking(at pH 7,I=10^(-1)mol·L^(-1)for pepsin,and pH 9,I=10^(-1)mol·L^(-1)for BSA).Furthermore,the isoelectric precipitation led to the adsorption of neutral protein(γ-globulin,whose isoelectric point was near the pK_a of PDMAEMA)at pH 7,I=10^(-5)mol·L^(-1),while electrostatic repulsion and antifouling PMOXA triggered the desorption of y-globulin at pH 3,I-10^(-1)mol·L^(-1).However,alkaline protein(lysozyme,whose isoelectric point was higher than the pK_(a) of PDMAEMA)exhibited slight adsorption on PMOXA/PDMAEMA mixed brushes under test conditions,regardless of whether PMOXA or PDMAEMA occupied the outermost layer.The antibacterial property of the mixed brushes against Escherichia coli was investigated.PMOXA/PDMAEMA mixed brushes showed significant bactericidal activity at pH 3,I=10^(-3)mol·L^(-1),while the rinse of pH 9,I=10^(-1)mol·L^(-1)solution could remove most of the residual bacteria.This work not only enables controlled adsorption of proteins with different isoelectric points but also ensures that the surface of the coating is minimized from bacterial contamination.展开更多
文摘OBJECTIVE: To assess the diagnostic value of endoscopic pancreatic duct brushing in detecting mutation of the K-ras gene at codon 12 in cytologic specimens from patients with pancreatic cancer. METHODS: Thirty-five patients treated at Changhai Hospital, Shanghai between 1999 and 2001 were enrolled. Their cells obtained by pancreatic duct brushing during endoscopic retrograde tholangiopancreatography (ERCP) were suspended with phosphate buffer solution (PBS). DNA of the cells was extracted and mutation of the K-ras gene at codon 12 detected by means of PCR-SSCP. RESULTS: The K-ras gene mutation rate of pancreatic cancer was 70%, which was higher than that of chronic pancreatitis (14%, P<0.05). K-ras gene mutation was not found in patients with pancreatic cystorcarcinoma and duodenum carcinoma. As to the location of pancreatic cancer, no significant difference was observed between the head, the body and tail. The sensitivity, specificity, accuracy of pancreatic duct brushing in detecting pancreatic cancer was 70%, 94%, and 83%, respectively. CONCLUSION: K-ras analysis of pancreatic brushing samples is helpful in the diagnosis of patients with early pancreatic cancer.
文摘Preoperative cytologic brushing and biopsy under direct Vision withfiberoptic colonoscopy(FC)and postoperative histopathologic examination wereperformed in 147 patients who were suspected of suffering from carcinoma of co-lon.In FC cytologic brushing,128 cases were positive for malignancy(87.1percent),18 false-negative(12.2 percent)and only one false-positive(0.7 percent).In the 146 FC biopsy specimens,124 were positive for malignancy(84 4 percent)and 22 false-negative and no false-positive.Combination of FC cytologic brushingwith FC biopsy could raise the diagnostic rate of colonic carcinoma to 95.2% anddecrease false-negative and false-positive because the two methods may replenisheach other in sampling and observation.Cytologic brushing is most valuable tothe early diagnosis of colonic carcinoma.When colonic stricture and obstructionprevent the colonoscope from reaching the lesion and FC biopsy cannot bedone,FC cytologic brushing is an effective method for diagnosis.The positiverate and false-negative rate of the cytologic brushing did not correlate to grosstyping,histopathologic typing and Dukes staging(P】0.05).The factorsinfluencing the correct diagnosis of colonic carcinoma by FC cytologic brushingare discussed in this paper.
文摘The effects of 3 chairside polishing kits and mechanical brushing on the surface roughness of 3 different acrylic denture base resins were compared. Acrylic denture base resins （auto-polymerizing, heat-polymerizing, injected heat-polymerizing resins） were examined after a tungsten carbide bur, and after chairside polishing using 3 polishing kits and pumice. The specimens were subjected to mechanical brushing using a wear tester to simulate 30 000 strokes of brushing. The surface roughness of the acrylic denture base resin specimens was measured using a contact pro-filometer. After the test, the random polished acrylic resins were evaluated by scanning electron mi-croscopy （SEM） and atomic force microscopy （AFM）. Acrylic denture base resins polished using the 3 types of polishing kits had a smoother surface than those finished with the tungsten carbide bur （p〈0.05）. The surface of the resin polished by a TC cutter exceeded the Ra of 0.2 μm （p〈0.05）. The auto-polymerizing resin showed a significantly higher surface roughness than the heat-polymerizing resin and injected heat-polymerizing resin （p〉0.05）. In the case of polishing step wise, there was almost no change in surface roughness after brushing （p〉0.05）.
文摘Introduction and Objective: The aim of this research was to find out the interaction of anthropometric measurements particularly body mass and oral health status of Turkish young adult nationals regionally, depending on the effects of diet (food and fluid consumption), smoking and tooth brushing habits, which were determined by using the body mass index (BMI) and dental health index (DMFT). Material and Methods: The BMI and DMFT of 202 cases, with an age average 22.5 years, were recorded through physical and clinical examinations. Statistical evaluation of the data was checked by Cronbach’s Alpha Reliability Scale and performed by analysis of variance, Somer’s d and Pearson Chi-Square statistics, Poisson Regression and Odds Ratio analysis. Results: The results showed that the mean of BMI was at the optimum level (21.52) for all cases. The DMFT was higher for underweight females and for overweight males. The mean of DMFT according to sexes seemingly had no significant difference;however, females had 8.6% more DMFT than males. When the risk factors of dental caries were evaluated, the DMFT was found as 19.3% more for cases consuming high carbohydrate foods, 4.5% more for high beverage consumption and 18% more for smokers. Conclusions: In conclusion, tooth brushing 3 or more times a day is necessary to decrease the DMFT and tooth brushing 3 times a day as opposed to 1 or 2 times shows significant difference regarding oral health.
基金supported by the Major International Cooperation Projects of the National Natural Science Foundation of China(No.81220108022)the National Natural Science Funds for Distinguished Young Scholars(No.81325018)+3 种基金the National Key Research and Development Program(No.2016YFC1302704)Guangdong Special Support Programs for High-level Personnel(No.2014TX01R201)the Science and Technology Project of Guangdong Province(No.2014B050504004)the Health&Medical Collaborative Innovation Project of Guangzhou City(No.201604020003).
文摘Background:Tissue specimens for nasopharyngeal carcinoma(NPC)research are scarce because of sampling dif-ficulties.Previous studies have suggested non-invasive nasopharyngeal brushing as an effective sampling method for NPC diagnosis.The present study aimed to evaluate the feasibility of nasopharyngeal brushing in the acquisition of NPC nucleic acids for research.Methods:Nasopharyngeal brushing samples were acquired from 24 healthy individuals and 48 NPC patients.Tissues from 48 NPC and 18 nasopharyngitis patients were collected by endoscopic biopsy.The expression levels of tumor suppressor genes(TSGs)and Epstein-Barr virus(EBV)-encoded microRNAs as well as EBV DNA copy number were measured by quantitative polymerase chain reaction in both types of samples.Results:Among six TSGs examined,the expression levels of two genes were significantly decreased in nasopharyn-geal brushing and tissue samples from NPC patients as compared with those from healthy/nasopharyngitis indi-viduals.Four EBV-encoded microRNAs,mir-bart1-5p,mir-bart5,mir-bart6-5p,and mir-bart17-5p,were significantly up-regulated in both NPC brushing and tissue samples compared with those from healthy/nasopharyngitis controls(P<0.001).EBV DNA was significantly increased in both nasopharyngeal brushing samples(P<0.001)and tissue sam-ples(P<0.001)from NPC patients in comparison with those from healthy controls.Conclusions:Nasopharyngeal brushing can obtain sufficient tumoral materials for the analysis of viral nucleic acid,including EBV-encoded microRNAs and EBV DNA.For the detection of TSG expression,nasopharyngeal brushings was feasible but inferior to tissue samples.This study confirms nasopharyngeal brushing as an applicable sampling method that can aid in nucleic acid-based NPC research.
基金supported by a Commercialization Promotion Agency for R&D Outcomes(COMPA)Grant funded by the Korean Government(Ministry of Science and ICT)(No.RS-2023-00304743)the National Research Foundation of Korea(NRF)Grant funded by the Korean Government(MSIT)(No.2022M3J7A1066428)"Regional Innovation Strategy(RIS)"through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(MOE)(No.2023RIS-008).
文摘A polarization-sensitive and flexible photodetector was fabricated through the precise alignment of perovskite nanowires(NWs)using a brush coating technique.The alignment of the NWs was meticulously examined,considering various chemical properties of the solvent,such as boiling point,viscosity,and surface tension.Notably,when the NWs were brush-coated with toluene dispersion,the NWs were aligned in higher order than those processed from octane dispersion.The degree of alignment was correlated with the photodetector property.Especially,the well-aligned NW photodetector exhibited a two-fold disparity in current response contingent on the polarization direction.Furthermore,even after enduring 500 bending cycles,the device retained 80%of its photodetector performance.This approach underscores the potential of solution-processed flexible photodetectors for advanced optical applications under dynamic operating conditions.
文摘Hello,everyone!I am Cici.I had a summer holiday that was both busy and happy.From July 11th to July 20th,I went to school every day to learn traditional Chinese painting.The soft brushes glided across the paper,creating beautiful and vivid images.
文摘一、阅读理解[核心素养·文化意识](2024·贵州铜仁一模) The brush pen, one of the “Four Treasures of the Study”, was invented thou-sands of years ago. However, the oldest pen was just a stick or a piece of bamboo. It was difficult for people to write well on thin silk.
基金supported by the National Science Foundation for Distinguished Young Scholars(No.52325308)the National Natural Science Foundation of China(Nos.52273008 and 52073092)+1 种基金Shanghai Scientific and Technological Innovation Projects(No.22ZR1479300)Shanghai Rising-Star Program(No.23QA1402500).
文摘Amphiphilic asymmetric brush copolymers(AABCs)possess unique self-assembly behaviors owing to their asymmetric brush architecture and multiple functionalities of multicomponent side chains.However,the synthesis of AABCs presents challenges,which greatly limits the exploration of their self-assembly behaviors.In this work,we employed dissipative particle dynamics(DPD)simulations to investigate the self-assembly behaviors of AABCs in selective solution.By varying the copolymer concentration and structure,we conducted the self-assembly phase diagrams of AABCs,revealing complex morphologies such as channelized micelles with one or more solvophilic channels.Moreover,the number,surface area,and one-dimensional density distribution of the channelized micelles were calculated to demonstrate the internal structure and morphological transformation during the self-assembly process.Our findings indicate that the morphology of the internal solvophilic channels is greatly influenced by the copolymer structure,concentration,and interaction parameters between the different side chains.The simulation results are consistent with available experimental observations,which can offer theoretical insights into the self-assembly of AABCs.
文摘人类对人体奥秘的探索与了解尚处初级阶段。本文提出的一个问题就让我们感到新奇与愕然。洁齿与口腔卫生有助于抑制糖尿病: Gum(齿龈)disease may even be more important than obesity or age as a factorin the onset of diabetes in adults。 上句可译:就诱发成年人糖尿病的因素而言,齿龈疾病也许比肥胖和年龄这两个因素更为重要。 因此,我们有必要认识:the importance of prevention and early treatment ofgum disease in people who are at risk of developing diabetes。 本文对inflammation([医]炎症,发炎)提出了一个颇有原创性的观点:…heart disease has a substantial inflammatory component。】
文摘What damage can be done to teeth by over-brushing?The enamel of the teeth ran he worn out;the gum can he hurt by over-brushing.And your teeth will feel sensitive if the enamel gets thinner and/or the gum recedes.How often should we be brushing our teeth?Two to three rimes a day.What is the recommended amount of time people should spend brushing their teeth?
基金funded by the National Key Research and Development Program of China,grant number 2023YFD1700303.
文摘Titanium dioxide(TiO_(2))hollow nanoparticles present significant potential for photocatalytic applications while their straightforward preparation with precise structure control is still challenging.This work reports the approach to preparing tunable hollow TiO_(2) nanospheres by utilization of spherical polyelectrolyte brushes(SPB)as nanoreactors and templates.During the preparation,the evolution of the structure was characterized by small angle X-ray scattering(SAXS),and in combination with dynamic light scattering and transmission electron microscopy.The formation of TiO_(2) shell within the brush(SPB@TiO_(2))is confirmed by the significant increase of the electron density,and its internal structure has been analyzed by fitting SAXS data,which can be influenced by Titanium precursors and ammonia concentration.After calcining SPB@TiO_(2) in a muffle furnace,hollow TiO_(2) nanospheres are produced,and their transition to the anatase crystal form is triggered,as confirmed by X-ray diffraction analysis.Utilizing the advantages of their hollow structure,these TiO_(2) nanospheres exhibit exceptional catalytic degradation efficiency of methylene blue(MB),tetracycline(TC),and 2,4-dichlorophenoxyacetic acid(2,4-D),and also demonstrate excellent recyclability.
基金the Qatar National Research Fund for funding this work through NPRP(10-0127-170270,acknowledged under the grant code KK-2018-008).
文摘Confronting the severe health threats and environmental impacts of Cr(Ⅵ) in aquatic environments demands innovative and effective remediation approaches. In this study, Graphene oxide(GO)-decorated poly(dimethyl amino ethyl methacrylate)(PDMAEMA) brush nanocomposites(GOP1, GOP2, GOP3, and GOP4) were fabricated using atom transfer radical polymerization(ATRP) by the “graft from” method.The resulting nanocomposites were utilized for removing Cr(Ⅵ) with good adsorption performance due to the electrostatic interaction of protonated nitrogen groups in the brush chains with negatively charged particles in the solution. The kinetic model of pseudo-second-order best represented the contaminants' adsorption characteristics. The Weber-Morris model further indicated that surface adsorption and intraparticle diffusion mechanisms primarily controlled the adsorption procedure. Additionally, the Langmuir and Temkin isotherm models were found to most accurately represent the adsorption characteristics of the pollutants on the nanocomposites, and GOP4 can achieve the maximum adsorption capacity of 164.4 mg·g^(-1). The adsorbents' capacity maintains above 85% after five cycles of adsorption-desorption. The nanocomposites in this study demonstrate promising potential for eliminating Cr(Ⅵ) from aqueous solutions.
文摘The aim of this study was to develop self-healable and robust elect roconductive film based on polyaniline copolymer for application as electrode in flexible supercapacitor.For this purpose,the electroconductive polymer brushes(EPB)was elaborated.The synthesis of EPB is based on graft polymerizations of acrylamide(AAm)on poly(vinyl alcohol)(PVA)with formation of PVA-PAAm polymer brush and subsequent graft copolymerization of aniline and p-phenylenediamine on PVA-PAAm resulting in formation of EPB with electroconducting copoly(aniline-co-pphenylenediamine)(PAPh DA).It was found that the ratio between PVA and PAAm at the first stage greatly influence the electrochemical performance of the EPBs.Electroconducting films were prepared by casting of EPB solution with subsequent drying.Investigation of electrical current distribution through the film with AFM reveal more uniform distribution of PAPhDA in EPB in comparison with reference PVA-PAPhDA and PAAm-PAPhDA samples.It was demonstrated that mechanical cha racteristics and electrical conductivity values of films restore at large extent after curring and self-healing under optimal relative humidity level(58%).The flexile supercapacitor cell with EPB film electrodes demon strate specific capacitance 602 mF·cm^(-2)at the current density of 1 mA·cm^(-2)and retention 94%of initial capacitance after 5000 charge/discharge cycles.
基金supported by the National Natural Science Foundation of China (Nos. 21574139 and 21973103)
文摘We present the results of molecular dynamics simulations of steady shear between a pair of neutral polymer brushes,as well as a pair of charged polymer brushes in the strongly compressed regime.The results of the molecular dynamic simulations of neutral and polyelectrolyte brushes in implicit solvent including normal forces,shear forces,viscosities and friction coefficients as a function of separation between brushes,are presented in the study.The comparison of the simulation results of neutral and charged brushes shows that the charged brushes is in the quasi-neutral regime,and the dependence of viscosity on the separation distance show the similar power law of neutral brushes.Our simulation results confirm that the implicit solvent simulations of polyelectrolyte brushes that ignore hydrodynamics interaction are in agreement with the scaling predictions qualitatively because of screening of hydrodynamic interaction and long-range electrostatic interactions on the correlation length scale.Both of neutral and charged brushes show the lubrication properties that the friction coefficient decreases with the separation decreases at enough large loads.However,a maximum of friction coefficients is observed for polyelectrolyte brushes,which is in contrast to the neutral brushes with monotonical dependence.
基金supported by the National Natural Science Foundation of China(Nos.22273098,52033001,22373003 and 22103002)the Fundamental Research Funds for the Central Universities(No.WK2480000007).
文摘The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to the charged groups of polyelectrolyte chains and act as hydrogen bond donors or acceptors to form hydrogen bonds with the hydrogen bond sites associated with polyelectrolyte chains simultaneously.A large number of literatures illustrate that strong polyelectrolytes(SPs)are insensitive to pH,which severely limmits the applications of SPs as smart materials.However,our studies have demonstrated that the CMHB makes SPs pH-responsive.This perspective discusses the mechanism of pH responsiveness of SPs and the pH-tunable properties of SPs,based on the pH-controlled CMHB effect.The future research directions on the pH responsiveness of SPs are also discussed here.It is anticipated that the study of the pH responsiveness of SPs not only will provide a new understanding of the fundamental properties of SPs,but also will greatly expand the applications of SPs in the field of smart materials.
基金supported by the National Natural Science Foundation of China(No.21978079).
文摘Polyelectrolyte brushes(PEBs)are commonly used to modify surface that have attracted great research interest.The dielectric permittivity of the grafted surface is typically significantly different from that of solution,which results in surface polarization(SP)effect with a jump of electric field.It is thus important to study how SP alters the PEB’s structure and properties.In this work,the SP effects on PEB structure was studied using a statistical thermodynamic theory.The free energy functional to describe SP effect was constructed by using the image-charge method.Meanwhile,the electrostatic potential was solved from a modified Poisson-Boltzmann equation taking the ion solvation effect into consideration.In the absence of SP,the thickness of PEB exhibited a continuous collapse transition when decreasing the solvent quality.In the presence of SP,the collapse became a jump-like transition.Free energy analysis showed that the long-range Coulombic interaction dominated the transition because of the enhanced counterion condensation in the presence of SP.The theory provides an effective tool to study SP effect on PEBs,and the results explain the underlying physics in PEB collapse transition.
基金supported by the National Natural Science Foundation of China(Nos.21673002,21473012 and 21173025).
文摘Polyelectrolyte solutions are more variable than uncharged macromolecule due to electrical interaction between charged molecules and surrounding counterions.Therefore,the subject of polyelectrolyte solutions has attracted a wide range of interests in both basic and applied research,and has also been extensively explored.However,the understanding of the molecular dynamics and conformation of polyelectrolytes in solution remains to be deepened,and universal consensus on some key issues have not been reached.Many methods have contributed to solving the above problems in different ways,including dielectric relaxation spectroscopy(DRS).In this perspective,we briefly reviewed the history of dielectric spectroscopic research on polyelectrolyte solution,with emphasis on summarizing our efforts.In particular,we expound the characteristics of DRS and its ability to obtain the internal information of the system of interest.Finally,we evaluate the advantages and limitations of the dielectric method and discussed future prospects of this field.
基金the financial support of the National Natural Science Foundation of China(21674102)。
文摘Herein,binary mixed brushes consisting of poly(2-methyl-2-oxazoline)(PMOXA)and poly(2-(dimethylamine)ethyl methacrylate)(PDMAEMA)with different chain lengths were fabricated by successive grafting of NH_(2)-terminated PMOXA and SH-terminated PDMAEMA onto polydopamine-anchored substrates.The mixed-brush coating was characterized by variable-angle spectroscopic ellipsometry,X-ray photoelectron spectroscopy,Fourier transform infrared spectroscopy,zeta potential measurements,water contact angle,and atomic force microscopy.The mixed brushes showed tunable surface charge,wettability,and surface roughness,depending on the degree of PDMAEMA swelling under varying pH and ionic strength(Ⅰ).Then the adsorption behaviors of pepsin,bovine serum albumin(BSA),γ-globulin,and lysozyme,four very different proteins with regard to isoelectric point,on the mixed brushes coating were studied by using fluorescence microscopy and surface plasmon resonance.When the chain length of PDMAEMA was about twice as long as PMOXA,the mixed brushes not only had high adsorption capacity for pepsin,BSA,and y-globulin but also had a desorption efficiency of 86.9%,87.1%,and 93.5%,respectively.It is explained that electrostatic attraction between the protonated PDMAEMA and positively charged acidic proteins(pepsin and BSA,whose isoelectric points were below the pK_(a) of PDMAEMA)would drive the intensive adsorption(at pH 3,I=10^(-3)mol·L^(-1)for pepsin,and pH 5,I=10^(-5)mol·L^(-1)for BSA),while desorption was dominated by the hydrophilic PMOXA when PDMAEMA was shrinking(at pH 7,I=10^(-1)mol·L^(-1)for pepsin,and pH 9,I=10^(-1)mol·L^(-1)for BSA).Furthermore,the isoelectric precipitation led to the adsorption of neutral protein(γ-globulin,whose isoelectric point was near the pK_a of PDMAEMA)at pH 7,I=10^(-5)mol·L^(-1),while electrostatic repulsion and antifouling PMOXA triggered the desorption of y-globulin at pH 3,I-10^(-1)mol·L^(-1).However,alkaline protein(lysozyme,whose isoelectric point was higher than the pK_(a) of PDMAEMA)exhibited slight adsorption on PMOXA/PDMAEMA mixed brushes under test conditions,regardless of whether PMOXA or PDMAEMA occupied the outermost layer.The antibacterial property of the mixed brushes against Escherichia coli was investigated.PMOXA/PDMAEMA mixed brushes showed significant bactericidal activity at pH 3,I=10^(-3)mol·L^(-1),while the rinse of pH 9,I=10^(-1)mol·L^(-1)solution could remove most of the residual bacteria.This work not only enables controlled adsorption of proteins with different isoelectric points but also ensures that the surface of the coating is minimized from bacterial contamination.
