Dual-functional poly(2-methyl-2-oxazoline)/poly(2-(dimethylamine)ethyl methacrylate)mixed brushes with switchable protein adsorption and antibacterial properties

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.

Sliding electrical contact behavior of AuAgCu brush on Au plating

The sliding electrical contact behavior of AuAgCu brush on Au plating was investigated at various normal loads and sliding speeds.The contact voltage drop and electrical noise between the two brushes were measured and the resistance waveforms were recorded.The morphologies of the worn surfaces and wear debris of the brush and plating were observed.The results show that the contact voltage drop and electrical noise decrease with the addition of load whereas increase drastically with increasing sliding speed.With the electrical current in vacuum,the wear process of AuAgCu brush on Au plating involves adhesion,transfer of gold from the plating to the brush,rolling of wear debris between contact surfaces and arc-induced melt at the contact edge,and this gold-on-gold sliding electrical contact system is reliable within experiment period.

How to Clean Your Sneakers

1 Mix warm water and a little detergent in a bowl.2 Take the shoelaces out of your sneakers.3 Brush the dirt from your sneakers with a brush.

口腔健康

The health of your teeth and gums affects your whole body.You should brush your teeth in the morning and before bed.Brushing them after you eat is also good.Remember to floss your teeth,too.Then your mouth will be clean,and your breath will be fresh!Since you use your toothbrush so often,be sure to get a new one every three months.

Endoscopic transpapillary brush cytology and forceps biopsy in patients with hilar cholangiocarcinoma

AIM: To evaluate the sensitivity of brush cytology and forceps biopsy in a homogeneous patient group with hilar cholangiocarcinoma.METHODS: Brush cytology and forceps biopsy were routinely performed in patients with suspected malignant biliary strictures. Fifty-eight consecutive patients undergoing endoscopic retrograde cholangio-pancreatography (ERCP) including forceps biopsy and brush cytology in patients with hilar cholangiocarcinoma between 1995-2005.RESULTS: Positive results for malignancy were obtained in 24/58 patients (41.4%) by brush cytology and in 31/58 patients (53.4%) by forceps biopsy. The combination of both techniques brush cytology and forceps biopsy resulted only in a minor increase in diagnostic sensitivity to 60.3% (35/58 patients). In 20/58 patients (34.5%), diagnosis were obtained by both positive cytology and positive histology, in 11/58 (19%) by positive histology (negative cytology) and only 4/58 patients (6.9%) were confirmed by positive cytology (negative histology).CONCLUSION: Brush cytology and forceps biopsy have only limited sensitivity for the diagnosis of malignant hilar tumors. In our eyes, additional diagnostic techniques should be evaluated and should become routine in patients with negative cytological and histological findings.

PIEZOELECTRIC PROPERTIES OF SINGLE-STRAND DNA MOLECULAR BRUSH BIOLAYERS

The paper is devoted to investigations on nanomechanical behaviors of biochips in label-free biodetections. The chip consists of Si-layer, Ti-layer, Au-layer and single-strand DNA （ssDNA） molecular brush biolayer immobilized by self-assembly technology of thiol group. Unlike previous viewpoints, such as force-bending, entropy-bending and curvature electricity effect, etc., the piezoelectric effect of the biopolymer brush layer is viewed as the main factor that induces nanomechanical bending of biochips, and a classical macroscopic piezoelectric constitutive relation is used to describe the piezoelectric effect. A new laminated cantilever beam model with a piezoelectric biolayer in continuum mechanics, the linearized Poisson-Boltzmann equation in statistical mechanics and the scaling method in polyelectrolyte brush theory are combined to es- tablish a relationship between the nanomechanical deflection of DNA chips and the factors such as nanoscopic structural features of ssDNA molecules, buffer salt concentration, macroscopic mechanical/piezoelectric parameters of DNA chips etc. Curve fitting of experimental data shows that the sign of the piezoelectric constant of the biolayer may control the deflection direction of DNA chips during the packaging process.

Influence of air addition on surface modification of polyethylene terephthalate treated by an atmospheric pressure argon plasma brush

An atmospheric pressure argon plasma brush with air addition is employed to treat polyethylene terephthalate(PET)surface in order to improve its hydrophilicity.Results indicate that the plasma plume generated by the plasma brush presents periodically pulsed current despite a direct current voltage is applied.Voltage-current curve reveals that there is a transition from a Townsend discharge regime to a glow one during one discharge period.Optical emission spectrum indicates that more oxygen atoms are produced in the plume with increasing air content,which leads to the better hydrophilicity of PET surface after plasma treatment.Besides,an aging behavior is also observed.The hydrophilicity improvement is attributed to the production of oxygen functional groups,which increase in number with increasing air content.Moreover,some grain-like structures are observed on the treated PET surface,and its mean roughness increases with increasing air content.These results are of great importance for the hydrophilicity improvement of PET surface with a large scale.

Comparison of brush and basket cytology in differential diagnosis of bile duct stricture at endoscopic retrograde cholangiopancreatography

BACKGROUND： A previous report has identified a significantly higher sensitivity of cancer detection for dedicated grasping basket than brushing at endoscopic retrograde cholangiopancreato- graphy （ERCP）. This study aimed to compare the diagnostic accuracy of Geenen brush and Dormia basket cytology in the differential diagnosis of bile duct stricture. METHOD： The current study enrolled one hundred and fourteen patients who underwent ERCP with both Geenen brush and Dormia basket cytology for the differential diagnosis of bile duct stricture at our institution between January 2008 and December 2012. RESULTS： We adopted sequential performances of cytologic samplings by using initial Geenen brush and subsequent Dormia basket cytology in 59 patients and initial Dormia basket and subsequent Geenen brush cytology in 55 patients. Presampling balloon dilatations and biliary stentings for the stricture were performed in 17 （14.9%） and 107 patients （93.9%）, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of Geenen brush cytology for the diagnosis of malignant bile duct stricture were 75.0%, 100.0%, 100.0%, 66.7% and 83.3%, respectively, and those of Dormia basket cytology were 64.5%, 100.0%, 100.0%, 58.5% and 76.3%, respectively （P=0.347 and 0.827 for sensitivity and accuracy, respectively）. The good and excellent cellular yields （≥grade 2） were obtained by Geenen brush and Dormia basket cytology in 88 （77.2%） and 79 （69.3%） patients, respectively.CONCLUSION： The sensitivity, specificity and accuracy of biliary sampling with a Dormia basket are comparable to those with conventional Geenen brush cytology in the detection of malignant bile duct stricture.

Composition and corrosion resistance of palladium film on 316L stainless steel by brush plating

Palladium films with good adhesive strength were deposited on 316L stainless steel by brush plating. Scanning electronic microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy （XPS）, mass loss tests and electrochemical methods were used to study the properties of the films. The brush plated palladium film mainly consisted of palladium. XPS analysis indicated that palladium was present in the films as metal state. The palladium plated stainless steel samples showed excellent corrosion resistance in boiling 20% H2SO4 solution and boiling acetic/formic acids with 0.005 mol/L Br- ions added. The corrosion rates of the palladium plated 316L stainless steel samples were about two orders of magnitude lower than those of the original 316L stainless steel samples. This method provides a possibility to prepare protective palladium films on stainless steel facilities with large areas in industrial sites.

Efficacy of SpyGlass^(TM)-directed biopsy compared to brush cytology in obtaining adequate tissue for diagnosis in patients with biliary strictures

AIM: To evaluate the diagnostic yield(inflammatory activity) and efficiency(size of the biopsy specimen) of SpyGlassTM-guided biopsy vs standard brush cytology in patients with and without primary sclerosing cholangitis(PSC).METHODS: At the University Medical Center Mainz, Germany, 35 consecutive patients with unclear biliarylesions(16 patients) or long-standing PSC(19 patients) were screened for the study. All patients underwent a physical examination, lab analyses, and abdominal ultrasound. Thirty-one patients with non-PSC strictures or with PSC were scheduled to undergo endoscopic retrograde cholangiography(ERC) and subsequent per-oral cholangioscopy(POC). Standard ERC was initially performed, and any lesions or strictures were localized. POC was performed later during the same session. The Boston Scientific SpyGlass SystemTM(Natick, MA, United States) was used for choledochoscopy. The biliary tree was visualized, and suspected lesions or strictures were biopsied, followed by brush cytology of the same area. The study endpoints(for both techniques) were the degree of inflammation, tissue specimen size, and the patient populations(PSC vs non-PSC). Inflammatory changes were divided into three categories: none, low activity, and high activity. The specimen quantity was rated as low, moderate, or sufficient.RESULTS: SpyGlassTM imaging and brush cytology with material retrieval were performed in 29 of 31(93.5%) patients(23 of the 29 patients were male). The median patient age was 45 years(min, 20 years; max, 76 years). Nineteen patients had known PSC, and 10 showed non-PSC strictures. No procedure-related complications were encountered. However, for both methods, tissues could only be retrieved from 29 pa-tients. In cases of inflammation of the biliary tract, the diagnostic yield of the SpyGlassTM-directed biopsies was greater than that using brush cytology. More tissue material was obtained for the biopsy method than for the brush cytology method(P = 0.021). The biopsies showed significantly more inflammatory characteristics and greater inflammatory activity compared to the cy-tological investigation(P = 0.014). The greater quantity of tissue samples proved useful for both PSC and non-PSC patients.CONCLUSION: SpyGlassTM imaging can be recom-mended for proper inflammatory diagnosis in PSC pa-tients. However, its value in diagnosing dysplasia wasnot addressed in this study and requires further investi-gation.

Properties and strengthening mechanism of brush plated nanoparticle reinforced composite coatings

Nanoparticle reinforced nickel matrix composite coatings, such as n-Al2O3/Ni, n-SiO2/Ni, n-SiC/Ni and n-TiO2/Ni, were fabricated by brush plating technique. Hardness, wear resistance and contact-fatigue resistance of the composite coatings were determined, and strengthening mechanism of the composite coatings was discussed. Results show that the composite coatings have superior properties to the Ni metal coating. Compared with properties of brush plated Ni metal coating, the composite coatings have hardness over 1.5 times and wear resistance capability of about 2.5 times. The strengthening mechanism of the composite coatings mainly includes fine-crystal grain effect, nanoparticle dispersion effect and dislocation effect.

Detection of K-ras gene mutation at codon 12 by pancreatic duct brushing for pancreatic cancer

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.

Friction and Wear Characteristics of Brush Plating Ni/nano-Al2O3 Composite Coating under Sand-Containing Oil

Ni-matrix composite coating containing AI2O3 nano-particles is prepared by brush plating. The effects of the nano-particles on the microstructure, microhardness and tribological properties of the composite coating under the lubrication of a diesel oil containing sand are investigated. The results show that the microstructure of the composite coating is finer than that of the pure nickel coating due to the codeposition of the nano-particles. When the nano-particle concentration in the electroplating bath reaches 20 g/L, the microhardness, and wear resistance of the composite coating is as much as 1.6 times and 1.3-2.5 times of those of the pure nickel coating respectively. The main hardening mechanism of the composite coating is superfine crystal grain strengthening and dispersion strengthening. The composite coating is characterized by scuffing as it slides against Si3N4 under the present test conditions.

Low temperature bonding of LD31 aluminum alloys by electric brush plating Ni and Cu coatings

Soldering of LD31 aluminum alloys using Sn-Pb solder paste after electric brush plating Ni and Cu coatings was investigated. The technology of electric brush plating Ni and Cu was studied and plating solution was developed. The microstructure of the coatings, soldered joint and fracture face were analyzed using optic microscopy, SEM and EDX. The shear strength of soldered joint could reach as high as 26.83MPa. The results showed that reliable soldered joint could be obtained at 230℃, the adhesion of coatings and LD31 aluminum alloy substrate was high enough to bear the thermal process in the soldering.

Microstructure and Contact Fatigue Behavior of Nano-SiO_2/Ni Coating Prepared by Electro-Brush Plating

The composite coating nano SiO 2/Ni was prepared by co depositing nano SiO 2 particles with pure nickel through electro brush plating. By taking into account the effect of microstructure, heat treatment and load on the contact fatigue life, the anti contact fatigue behavior of the composite coating was examined and compared with that of nickel coating. As a result, the contact fatigue life decreased with the increasing of load. The contact fatigue lives of nano SiO 2/Ni coating were 16.5% and 45.2% higher than those of nickel coating respectively under the loads of 60 N and 140 N, and 326.3% higher than its counterpart of nickel coating after annealed under the load of 140 N. From the SEM image of fatigue fracture, it has been observed that the fatigue fracture of the composite coating initiated in the sub surface as well as at the track surface due to the huddling of units, and propagated along the interface between grain units.

Deposition of stain resistance coating by non-thermal plasma brush application to dental whitening

A non-thermal plasma brush is employed to deposit stain-resistant SiO2-like coatings on resin composite fillings and bovine teeth.With post-treating by plasma,the hardness of the coating increases from H to 8H and the water contact angle decreases from 98.8° to 61.7°.The Fourier transform infrared spectroscopy (FTIR) results show that,after plasma post-treating,the Si-O-Si and Si-OH bonds of the coating increase.Scanning electron microscope (SEM) images show the coatings to be uniform,without cracks.The coatings present outstanding performance in a stain resistance test both on resin composite and bovine teeth.Being easy to handle and less time consuming than traditional methods,with a body-friendly temperature and material,this plasma brush provides a promising in-situ coating method on patient teeth in dental clinics.

Formation of surface-attached microstructured polyelectrolyte brushes

Surface-attached micropattemed polyelectrolyte brushes on planar solid surfaces are generated using free radical polymerization photo-initiated by self-assembled initiator monolayers. It is shown that the formed patterns can be either negative or positive with different patterning processes.

The Mathematical Simulation of Brush Drums in a Dual Saw Cylinder Chamber Gin for the Purpose of Increasing the Quantity of Captured Cotton Fiber from Saw

An analysis of the efficiency of the ginning of cotton fibers with two saw cylinders has been carried out. In comparison to a one-cylinder machine, the 2 cylinder approach can help to preserve the natural characteristics of cotton fiber and seeds. This technology allows economizing electricity and decreasing damage to fiber and also increases the productivity of the machine.

Morphologies of a spherical bimodal polyelectrolyte brush induced by polydispersity and solvent selectivity

It is commonly realized that polydispersity may significantly affect the surface modification properties of polymer brush systems. In light of this, we systematically study morphologies of bidisperse polyelectrolyte brush grafted onto a spherical nanocolloid in the presence of trivalent counterions using molecular dynamics simulations. Via varying polydispersity, grafting density, and solvent selectivity, the effects of electrostatic correlation and excluded volume are focused, and rich phase behaviors of binary mixed polyelectrolyte brush are predicted, including a variety of pinned-patch morphologies at low grafting density and micelle-like structures at high grafting density. To pinpoint the mechanism of surface structure formation, the shape factor of two species of polyelectrolyte chains and the pair correlation function between monomers from different polyelectrolyte ligands are analyzed carefully. Also, electrostatic correlations, manifested as the bridging through trivalent counterions, are examined by identifying four states of trivalent counterions. Our simulation results may be useful for designing smart stimuli-responsive materials based on mixed polyelectrolyte coated surfaces.