Objective:To investigate the effect of silver diamine fluoride(SDF)on the bonding strength between dentine and glass ion-omer cement(GIC).Methods:1 2 extracted sound molars were prepared into dintine samples and distributed into sound dentine group and demineralized dentine group.According to the treatment methods,the samples in each group were respectively divided into 3 sub-groups:A(control group),B[coated with 38% Ag(NH3 )F2 ]and C(SDF treatment with additional lighting-curing)(n =20).Then a hand-mixed conventional glass ionomer cement Fuji IX was placed on the dentine surface.After 24 h,micro tensile bond strength test and scanning electron microscope (SEM)analysis were conducted.Results:The bonding strength of demineralized dentine was higher than that of sound dentine(P <0.01 ).SDF with additional lighting-curing treated dentine showed a higer bonding strength value than only SDF treated dentin(P <0.01 ).Conclusion:SDF may improve the bonding between dentine and GIC.

Objective To develop a simple microfluidic chip technology for analyzing the electrotaxis of cancer cells . Methods The basic structure of the proposed microfluidic electrotaxis chip included a straight microchannel and liquid storage pools located on both sides of the microchannel .Two platinum electrodes were inserted into the liquid pools to create a controllable direct current ( DC ) field in the microchannel .The distribution and strength of the DC field in the microchannel was analyzed by the finite element analysis software COMSOL multiphysics and experiment tests .Finally, the electrotactic behavior of the rhabdomyosarcoma RD cells in the DC field of different strength was characterized using the accumulated distance, average velocity, x forward migration index ( xFMI) and y forward migration index ( yFMI) as quantitative parameters.Results The results of element analysis and experiments showed that the structure of the designed microfluidic electrotaxis chip was able to guarantee a uniform and strength-controllable DC field in the microchannel .The experiment of cell electrotaxis showed that the RD cells migrated toward the anode of the DC field .Meanwhile , the values of xFMI and accumulated distance for RD cells increased with the enlargement of the DC field , with the strength ranging from 188 to 1320 V/m.Conclusion The microfluidic chip technology developed in this paper for assaying the electrotaxis of cancer cells is simple and easily implementable , and it can be used for studies of the electrotactic behavior and underlying mechanisms of various cancer cells and normal cells in the future .

Objective To establish a method for detection of aminophylline in blood samples of preterm infants . Methods A molecularly imprinted electrochemical sensing film on the glassy carbon electrode surface was prepared by electropolymerization using aminophylline as the template molecule and pyrrole as the functional monomer in 0.2 mol/L HAc-NaAc buffer solution ( pH 4.0).The surface morphology and properties of molecularly imprinted sensing films were characterized by three dimensional laser scanning microscopy , differential pulse voltammetry ( DPV) and electrochemical impedance spectroscopy ( EIS) while the effects of scanning cycle number and incubation time were investigated by square wave voltammetry(SWV) method in 5 mmol/L K3[Fe(CN)6] -0.1 mol/L KCl solution.Results Under optimized experimental conditions ,the SWV peak current difference was linear to the negative logarithm of aminophylline concentration in the range from 1.0 ×10 -7 to 1.0 ×10 -3mol/L with a detection limit (S/N=3) of 0.5 ×10 -8mol/L.The recovery rate was 92.2% -101.4%.Also, the molecularly imprinted electrochemical sensor for aminophylline had good selectivity , stability and reproducibility .Conclusion The molecularly imprinted electrochemical sensor for aminophylline can be used for rapid and accurate detection of clinical blood concentrations of aminophylline molecules in preterm infants in the future .

Objective To explore the significance of palpation-negative breast tumor resection with ultrasound-guided methylene blue labeling and percutaneous suture traction.Methods 46 cases of small breast tumors with the diameter from 0.5 cm to 1.0 cm were double labeled with methylene blue under the guide of ultrasound l hour preoperatively.The tumors were fixed,drew outward with percutaneous suture and resected accurately.All the 46 cases were rechecked by ultrasound to verify whether residual or false resection occurred 1 month later.Results All the 58 tumors of the 46 patients were accurately resected.No residue or false resection occurred.The average operation duration was 10 min to 20 min.Conclusion Palpable-negative breast tumor resection with ultrasound-guided methylene blue labeling and percutaneous suture traction has the advantages of small invasion,accurate positioning and short operation duration.

In this study,a fluorescent(FL)aptasensor was developed for on-site detection of live Salmonella typhimurium(S.T.)and Vibrio parahaemolyticus(V.P.).Complementary DNA(cDNA)of aptamer(Apt)-functionalized multicolor polyhedral oligomeric silsesquioxane-perovskite quantum dots(cDNA-POSS-PQDs)were used as encoded probes and combined with dual-stirring-bar-assisted signal amplification for pathogen quantification.In this system,bar 1 was labeled with the S.T.and V.P.Apts,and then bar 2 was functionalized with cDNA-POSS-PQDs.When S.T.and V.P.were introduced,pathogen-Apt complexes would form and be released into the supernatant from bar 1.Under agitation,the two complexes reached bar 2 and subsequently reacted with cDNA-POSS-PQDs,which were immobilized on MXene.Then,the encoded probes would be detached from bar 2 to generate FL signals in the supernatant.Notably,the pathogens can resume their free state and initiate next cycle.They swim between the two bars,and the FL signals can be gradually enhanced to maximum after several cycles.The FL signals from released encoded probes can be used to detect the analytes.In particular,live pathogens can be distinguished from dead ones by using an assay.The detection limits and linear range for S.T.and V.P.were 30 and 10 CFU/mL and 102-106 CFU/mL,respectively.Therefore,this assay has broad application potential for simultaneous on-site detection of various live pathogenic bacteria in water.

Objective To explore the effects of lung rehabilitation using Spiro-tiger training apparatus on the respiratory mechanics and airway remodeling in patients with chronic obstructive pulmonary disease(COPD)in stable stage.Methods Ninety-three stable COPD patients admitted to Nanxiang Branch of Shanghai Ruijin Hospital were randomly divided into control group(46 cases)and observation group(47 cases).Control group was treated with the training for pursed lips breathing and abdominal breathing,and observation group was trained with Spiro-tiger training apparatus in addition to the treatment given to control group.Both groups were intervened continuously for 9 weeks.The two groups were compared in terms of respiratory mechanics(respiratory frequency,tidal volume,minute ventilation,and peak respiratory pressure),airway remodeling[matrix metalloproteinase-9(MMP-9),vascular endothelial growth factor(VEGF),and transforming growth factor-β1(TGF-β1)],and lung function[forced vital capacity(FVC),forced expiratory volume in the first second(FEV1),and FEV1/FVC],blood gas analysis indexes[arterial partial pressure of oxygen(PaO2),arterial partial pressure of carbon dioxide(PaCO2)],6-minute walking distance(6MWD)and health status[Borg scale and St.George's respiratory questionnaire(SGRQ)].The patients were followed up for 6 months,and the incidence of acute exacerbation of COPD was recorded.Results After 9 weeks of intervention,compared with control group,observation group had lower peak respiratory frequency and respiratory pressure,and higher tidal volume(P<0.05).There was no significant difference in minute ventilation between two groups(P>0.05).The levels of MMP-9,VEGF,TGF-β1 and PaCO2 were lower,and FVC,FEV1,FEV1/FVC and PaO2 were higher in observation group than in control group(P<0.05).Observation group had longer 6MWD,and lower Borg score and SGRQ score as compared with control group(P<0.05).After 6-month follow-up,the incidence of COPD acute exacerbation in observation group was lower than that in control group(4.26%vs19.57%,P<0.05).Conclusion Lung rehabilitation using Spiro-tiger training apparatus can effectively improve respiratory mechanics,lung function,blood gas analysis indexes and health status in stable COPD patients,alleviate airway remodeling,and avoid acute exacerbation of COPD.

Abscisic acid, a plant hormone that inhibits growth, is a key factor in balancing plant endogenous hormones and regulating growth and metabolism. Abscisic acid can improve the drought resistance and salt tolerance of crops, reduce fruit browning, reduce the incidence rate of malaria and stimulate insulin secretion, so it has a broad application potential in agriculture and medicine. Compared with traditional plant extraction and chemical synthesis, abscisic acid synthesis by microorganisms is an economic and sustainable route. At present, a lot of progress has been made in the synthesis of abscisic acid by natural microorganisms such as Botrytis cinerea and Cercospora rosea, while the research on the synthesis of abscisic acid by engineered microorganisms is rarely reported. Saccharomyces cerevisiae, Yarrowia lipolytica and Escherichia coli are common hosts for heterologous synthesis of natural products due to their advantages of clear genetic background, easy operation and friendliness for industrial production. Therefore, the heterologous synthesis of abscisic acid by microorganisms is a more promising production method. The author reviews the research on the heterologous synthesis of abscisic acid by microorganisms from five aspects: selection of chassis cells, screening and expression enhancement of key enzymes, regulation of cofactors, enhancement of precursor supply and promotion of abscisic acid efflux. Finally, the future development direction of this field is prospected.
Abscisic Acid/metabolism* ; Plant Growth Regulators/metabolism* ; Plants/metabolism* ; Yarrowia/metabolism*