A knife-edge method is used here to measure the beam width of the highly repetitive high-power thin disk Yb:KYW femtosecond laser (MABEL-Mannheim Biomedical Engineering Lab, University of Heidelberg, Germany). Presented in this paper is the detailed measuring process together with the results verified by theoretical calculating and scanning electron microscope measurements respectively. Therefore, it is concluded that the knife-dege method is an effective beam width measurement tool of high-power femtosecond lasers.
Bioengineering ; instrumentation ; Lasers ; Microscopy, Electron, Scanning ; instrumentation

Sutures may cause endothelial trauma and occlusion. The vascular clip system (VCS) clip applier may minimize endothelial injury. Fourteen carotid arteries of nine adult rabbits were transected and re-anastomosed with either #7-0 polypropylene (Group I, n=8) or VCS clips (Group II, n=6). The animals were sacrificed at 1, 3, 8, 14, and 30 days postoperatively. The operation time and bleeding amount were checked for each anastomosis. Carotid angiograms, photography, H&E staining and scanning electron microscopy (SEM) were performed. Fibrin and thrombus, inflammatory cell infiltration, endothelial disruption, luminal distortion, fibrosis, and wall thickening were compared. The luminal diameter was greater in group II. There were minimal differences in thrombosis, wall thickening and fibrosis between the two groups. However, fibrin, inflammatory cell infiltration, multinucleated giant cell formation, endothelial disruption, and luminal distortion were greater in group I. On SEM, group I showed trans-mural penetration. In contrast, group II showed suture margin eversion and no transmural penetration. Stenosis was greater in group I than in group II on carotid angiogram. The operation time was shorter in group II than in group I, i.e. 5+/-1.4 min vs. 11+/-3.8 min, respectively. The current data showed similar or superior results with VCS clips in comparison to conventional suturing with polypropylene.
Angiography ; Animal ; Arteriovenous Shunt, Surgical/*instrumentation/methods ; Carotid Arteries/pathology/*surgery/ultrastructure ; Microscopy, Electron, Scanning ; Rabbits ; Surgical Stapling/*instrumentation/methods

OBJECTIVETo investigate the nitrifying characteristics of both suspended- and attached-biomass in a hybrid bioreactor.

METHODSThe hybrid biological reactor was developed by introducing porous ceramic particles into the reactor to provide the surface for biomass attachment. Microorganisms immobilized on the ceramics were observed using scanning electron microscopy (SEM). All chemical analyses were performed in accordance with standard methods.

RESULTSThe suspended- and attached-biomass had approximately the same nitrification activity. The nitrifying kinetic was independent of the initial biomass concentration, and the attached-biomass had a stronger ability to resist the nitrification inhibitor.

CONCLUSIONThe attached biomass is superior to suspended-biomass for nitrifying wastewater, especially that containing toxic organic compounds. The hybrid biological reactor consisting of suspended- and attached-biomass is advantageous in such cases.

Biomass ; Bioreactors ; Cells, Immobilized ; Ceramics ; Microscopy, Electron, Scanning ; Nitrogen ; metabolism ; Phenol ; pharmacology ; Sewage ; Waste Disposal, Fluid ; instrumentation

The effect of hemodialysis on the mechanical behavior of a cellulosic Hemophane ME-IOH and one Polysulfone type hollow fibers was investigated. Mechanical tests showed that the deformation of polysulfone type of hollow fibers is entirely different than that of the other dialyser for the samples used and unused in hemodialysis. All the samples exposed to the dialysis showed decreased in ductility. Fracture surface studies proved that there was some alignment on the fracture surface. XRD and DSC experiments revealed structural changes had occurred.
*Biocompatible Materials ; Biomechanics ; *Cellulose/*analogs & derivatives ; Materials Testing ; *Membranes, Artificial ; Microscopy, Electron, Scanning ; *Polymers ; Renal Dialysis/*instrumentation ; *Sulfones ; Surface Properties

OBJECTIVEApplication of rapid expansion of supercritical solution (RESS) in preparing micropaticles of SCF-CO2 extraction of Salvia miltiorrhiza.

METHODThe mixture which was composed of beta-cyclodextrin and SCF-CO2 extraction of S. miltiorrhiza with proportion 8:1 by weight, was granulated by RESS. The characteristics of the resululting particles were studied by scanning electron microscopy (SEM) and the assay of salviol IIA in particles which was determinated by HPLC.

RESULTThe resulting particles were jacinth and photomicrograph produced by SEM showed that the morphology were silkiness and rugosity globular, the size distribution between 2 and 80 microm, and the contents of salviol IIA was 0.54%.

CONCLUSIONThe RESS method is applicable for preparing microparticles of SCF-CO2 extraction of S. miltiorrhiza and low operating temperature, simple processing, and no environmental pollution, and no residual solvent.

Chromatography, High Pressure Liquid ; Drugs, Chinese Herbal ; chemistry ; Microscopy, Electron, Scanning ; Nanostructures ; Salvia miltiorrhiza ; chemistry ; Technology, Pharmaceutical ; instrumentation ; methods

Pseudomonas sp. ZD8 isolated from contaminated soil was immobilized with platane wood chips to produce packing materials for a novel biofilter system utilized to control restaurant emissions. The effects of operational parameters including retention time, temperature, and inlet gas concentration on the removal efficiency and elimination capacity were evaluated. Criteria necessary for a scale-up design of the biofilter was established. High and satisfactory level of rapeseed oil smoke removal efficiency was maintained during operation and the optimal retention time was found to be 18 s corresponding to smoke removal efficiency greater than 97%. The optimal inlet rapeseed oil smoke loading was 120 mg/(m(3) x h) at the upper end of the linear correlation between inlet loading and elimination capacity.
Air Pollutants ; isolation & purification ; Biodegradation, Environmental ; Cells, Immobilized ; Filtration ; instrumentation ; methods ; Microscopy, Electron, Scanning ; Oils ; metabolism ; Pseudomonas ; metabolism ; ultrastructure ; Restaurants ; Smoke ; Temperature ; Time Factors ; Waste Management ; instrumentation ; methods

OBJECTIVE:To evaluate the biodurability of the covering material in retrievable metallic stents covered with polycarbonate polyurethane. MATERIALS AND METHODS: Using a peristaltic pump at a constant rate of 1ml/min, bile was recirculated from a reservoir through a long tube containing four stents. Each of these was removed from the system every two weeks and a radial tensile strength test and scanning electron microscopy (SEM) were performed. Each stent, removed at 2, 4, 6 and 8 weeks, was compared with a control stent not exposed to bile juice. RESULTS: Gross examination showed that stents were intact at 2 weeks, but at 4, 6 and 8 weeks cracks were observed. The size of these increased gradually in accordance with the duration of exposure, and at 8 weeks several large holes in the polyurethane membrane were evident. With regard to radial tensile strength, extension and peak load at break were 84.47% and 10.030 N/mm, 54.90% and 6.769 N/mm, 16.55% and 2.452 N/mm, 11.21% and 1.373 N/mm at 0, 2, 4 and 6 weeks, respectively. Scanning electron microscopy at 2 weeks revealed intermittent pitting and cracking, and examination at 4, 6 and 8 weeks showed that the size of these defects was gradually increasing. CONCLUSION: When the polyurethane membrane was exposed to bile, biodegradation was first observed at week two and increased gradually according to the duration of exposure.
Bile Acids and Salts/physiology ; Biodegradation ; Hydrogen-Ion Concentration ; Microscopy, Electron, Scanning/*instrumentation ; Phantoms, Imaging ; *Polyurethanes ; *Stents ; Support, Non-U.S. Gov't ; Tensile Strength ; Time Factors

OBJECTIVETo investigate the stress shielding rate, ultrastructural and biomechanical property of the healing bone fixed by Swan-like Shape Memory Connector (SMC) during experimental fracture healing in rabbits.

METHODSUnilateral osteotomy of left humeral diaphysis was performed in 140 adult New Zealand rabbits. The humeral fracture was fixed with SMC in study group and 4-hole dynamic compression plate (DCP) in control group. The animals were sacrificed at the 2nd, 4th, 8th, 12th, and 16th weeks postoperatively. The humeral shafts were harvested for three-point bending tests and stress shielding rate examination. Samples from the fracture gaps were observed with scanning electron microscope.

RESULTSWithin an observation period of 12 weeks after operation, the stress shielding rates were significantly lower in study group than those in control group, and the bending strength and the bending rigidity were statistically higher. It was also found that collagen fibers in callus was arranged more regulate and early mineral deposition in study group.

CONCLUSIONThese results suggest that SMC contributes to the proliferation and differentiation of osteoblasts, promoting the formation and calcification of bone matrix and enhancing biomechanical property of the healing bone, which might be closely correlated with a less stress shielding effect produced by SMC.

Animals ; Bony Callus ; physiopathology ; Fracture Fixation, Internal ; instrumentation ; Fracture Healing ; Humeral Fractures ; pathology ; physiopathology ; surgery ; Male ; Microscopy, Electron, Scanning ; Nickel ; Rabbits ; Stress, Mechanical ; Titanium

OBJECTIVETo investigate the effect of autocontrol micromotion locking nail (AMLN) on experimental fracture healing and its mechanism.

METHODS16 goats undergoing both sides of transverse osteotomy of the femoral shafts were fixed intramedullary with AMLN and Gross-Kempf (GK) nail, respectively. The follow-up time was 7, 14, 28 and 56 days. Roentgenographic, biomechanical, histological, scanning electromicroscopic and biochemical analyses were done.

RESULTS(1) The strength of anticompression, antiflexion and antitorsion in the fractural end in the AMLN-fixed group was higher than that of GK nail-fixed group; whereas, the rate of stress shelter in the fractured end decreased significantly (P<0.01). (2) The content of the total collagen, insoluble collagen, calcium and phosphate in the AMLN-fixed group was higher than that in the GK nail-fixed group (P<0.05). (3) Histological observation and quantitative analysis of calluses revealed that AMLN could promote the growth of bridge calluses and periosteum calluses. Hence the fracture healing and remolding process achieved early, which was much better than traditional GK nail fixation. (P<0.05). (4) 7-14 days postoperation, the calluses of AMLN-fixed group was flourish and camellarly arranged and the collagen fibril formed constantly in the absorption lacuna of bone trabecula. 28-56 days postoperation, the collagen fibril was flourish around the absorption lacuna and was parallel to the bone's longitudinal axis. Active bony absorption and formation were seen, so was remolding and rebuilding. Haversian system was intact and the bony structural net was very tenacious because of the deposition of calcium salt. None of the above findings was observed in the GK nail-fixed group.

CONCLUSIONSThe design of AMLN accords well with the plastic fixation theory. As the geometry ametabolic system constituted by the intramedullary fixation instruments and the proximal and distal end of the fracture is very firm and stable, the disturbance to the physical stress distributed in the fractural end is light. The generation and conduct of the intermittent physical stress between the fractural parts could reach the balance between stress conduct and stress protection. The feature that the healing and remolding take place at the same time speeds up the fractural healing process.

Animals ; Biomechanical Phenomena ; Bone Nails ; Femoral Fractures ; surgery ; Fracture Fixation, Intramedullary ; instrumentation ; Fracture Healing ; physiology ; Goats ; Microscopy, Electron, Scanning ; Stress, Mechanical

OBJECTIVETo evaluate the microleakage of fiber post and core systems after high-speed handpiece preparation at different time points.

METHODSThe crowns of forty-five extracted human premolar were removed and the roots were endodontically treated. The samples were devided into five groups. Root canal preparation was performed on each premolar followed by fiber post cementation and core build up. Tooth preparation was applied at 5 min in group 1, at 15 min in group 2 and at 30 min in group 3 after post cementation. Five teeth with only 5 mm apical sealing were served as a positive control group, and ten with fiber post and core build-up but no coronal preparation were taken as a negative control group. Microleakage was evaluated using a fluid filtration system. The bonding interface was observed by scanning electronic microscope (SEM).

RESULTSThe microleakage was significantly increased after coronal preparation with high-speed handpiece. The negative control group has less leakage [(1.50 × 10(-6) ± 0.37 × 10(-6)) µl×min(-1)×Pa(-1)] than the groups with coronal preparation (P < 0.05); Group 1 leaked significantly more [(6.02 × 10(-5) ± 1.02 × 10(-5)) µl×min(-1)×Pa(-1)] than group 2 [(1.50 × 10(-5) ± 0.26 × 10(-5)) µl·min(-1)×Pa(-1)] and group 3 [(1.50 × 10(-5) ± 0.39 × 10(-5)) µl×min(-1)×Pa(-1)] did (P < 0.05). Corresponding to microleakage, the micro gaps between the resin cement and dentine in group 1 were wider than those in the other groups. The coronal section was wider than the apical part.

CONCLUSIONSHigh-speed handpiece had negative effects on microleakage of fiber post and core systems. Coronal preparation should be performed 15 min or more after post cementation.

Cementation ; Dental Bonding ; Dental Leakage ; Dentin-Bonding Agents ; Humans ; Microscopy, Electron, Scanning ; Post and Core Technique ; instrumentation ; Resin Cements ; Root Canal Preparation ; Time Factors