Amount Of Adhesion Research Articles

Evaluation of Candida albicans adherence on the surface of various maxillofacial silicone materials

Fungal infection resulting from Candida adherence on material surface is one of the most important medical risks for maxillofacial prosthesis wearers. Despite wide usage, there is a sparse data evaluating C. albicans adherence on various commercial maxillofacial silicone materials that have different surface contact angles. The objective of this study was to investigate the relationship between surface contact angle and fungal adherence on widely used maxillofacial silicone materials. Three maxillofacial silicone materials titled VST-50, A-2006, and A-2186F were used for fabrication of disc-shaped specimens. Surface contact angle of specimens were measured by the goniometric method. Adhesion quantity of two different C. albicans strains was evaluated with a colorimetric method using XTT/Coenzyme Q0. The Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis of data. The lowest surface contact angle values with the highest Candida adhesion quantity were measured on the specimens fabricated with A-2006 silicone material. Statistically significant differences were found among three maxillofacial silicone materials in terms of both surface contact angle values and adhesion quantity (P<0.01). There is a close relationship between surface contact angle and quantity of Candida adherence. However, it should be noted that various factors arising from material properties may affect the complex nature of the Candida adhesion process.

Case Studies of Foamed Adhesive Failures of Low Sloped Roofing Rigid Insulation Board

Abstract In low sloped roofing systems, poorly adhered roofing assemblies are unable to resist significant wind loads and are likely to be further damaged or destroyed by wind events well below the design wind pressures for the assembly. The design and installation of rigid insulation boards are a critical parameter in the service life of this roofing assembly in that, if the insulation boards become detached, there is increased risk for complete roofing assembly failure. Foamed adhesive is a common alternative to traditional hot-mopped asphalt adhesive in contemporary roofing assemblies. The proper design and installation of insulation board roofing assemblies in foamed adhesive is paramount to the successful performance of these roofing assemblies. Some of the critical parameters that could influence foamed adhesive performance are: insulation board adhesive pattern defects; insulation board adhesive quantity; inadequate insulation board adhesive contact; and failure to maintain insulation board contact with the substrate until the insulation adhesive is sufficiently set. The present paper discusses these critical parameters through case studies that clearly demonstrate how these parameters can lead to the failure of roofing assemblies, and discusses the lessons to be learned from these insulation board adhesion failures.

A prospective, randomized, experimental study to investigate the peritoneal adhesion formation of noncontact argon plasma coagulation in a rat model

To investigate the peritoneal adhesion formation of two pulsed noncontact argon plasma coagulation (APC) modes in a rat model. Prospective, randomized, controlled, and blinded study. Laboratory facilities of a university department of obstetrics and gynecology. Ten female Wistar rats. Bilateral lesions were created on the abdominal wall with low and high APC energy in a standard fashion. After 10 days the rats were killed to evaluate the peritoneal trauma sites. Adhesion incidence, quantity, and quality were scored 10 days after surgery and studied by histopathologic analysis. The area of coagulation was 30 ± 8.4 mm(2) in the case of high APC energy and 12 ± 5.6 mm(2) (low APC energy). Macroscopic thermal damage of the peritoneum is significantly higher when applying high APC energy. Adhesions due to APC with high energy occurred in 64% and with low energy in 6% of cases. High energy results mainly in dense adhesions. The lesions in the high-energy group showed intense granulation tissue formation with centrally located myocyte necrosis with intense neutrophilic inflammation. This study describes for the first time that different noncontact APC energy settings induce peritoneal adhesions in a reproducible rat model. Higher energy produced significantly deeper tissue defects and adhesions of higher grade. A plasma coagulation system that develops fewer adhesions can be achieved by lower temperature and a more homogeneous application and if the application area desiccates more slowly.

The effectiveness of local anesthetics in preventing postoperative adhesions in rat models

Intra-abdominal adhesions are fibrous bands that develop after abdominal surgery or inflammation and cause significant surgical morbidity and mortality. In this study, the effectiveness of lidocaine, prilocaine and bupivacaine in preventing experimental intra-abdominal adhesions in rats was studied. After obtaining the approval of our local institutional review board, 50 female Wistar-Albino rats weighing 250-320g underwent laparotomy via a standard 5-cm midline incision under intramuscular anesthesia with ketamine (40mg/kg) and xylazine (10mg/kg). The cecal serosa and adjacent abdominal wall were superficially injured using sterile gauze. The laparotomy incision was closed after irrigation of the peritoneal cavity with the following: 5ml saline in Group II, (the sham group), 7mg/kg prilocaine in Group III, 3mg/kg lidocaine in Group IV or 2mg/kg bupivacaine in Group V. No irrigation was performed in Group I rats (the control group). After laparotomy closure, all rats were allowed to wake spontaneously. Two weeks after the initial experimental procedure, all rats underwent a second laparotomy, and adhesions were scored using the Linsky scale. The adhesion quantity and quality were comparable among all groups (P>0.05); however, adhesion severity scores were significantly lower in the prilocaine and bupivacaine groups vs. the other groups (P<0.05). Prilocaine and bupivacaine were found to decrease the severity of intra-peritoneal adhesions.

An Improved Model for the Induction of Experimental Adhesions

ABSTRACTBackground: The creation of ischemic buttons from parietal peritoneal tissue using a ligature is among the most established models for adhesion induction. However this model is plagued by slipping of ligatures and subsequent obliteration of the buttons when the animals mobilize postoperatively. Here we describe an improved model that involves creating the buttons with a backstitch ligature and compare it to the traditional model. Methods: A total of 160 ischemic buttons were created in 20 adult Wistar rats. Ischemic buttons in the control group (n == 80) were created using the traditional technique whereas ischemic buttons in the investigative group (n == 80) were created using the novel technique with a backstitch ligature. The resulting adhesions and the frequency of slipped ligatures were analyzed on postoperative day 10. Results: Slipping of the ligature with obliteration of the button occurred in 18.8%% (n == 15/80) of buttons in the control group and in 3.8%% (n == 3/80) of buttons in the investigative group (p < .01). Adhesions formed to 69.2%% (n == 45/65) of the remaining buttons in the control group and to 62.3%% (n == 48/77) of the remaining buttons in the investigative group (p == .38). Conclusion: There was no statistically significant difference in adhesion quantity between the models. However, the novel technique significantly reduced postoperative slipping of the ligatures with obliteration of buttons. As a result, a greater number of intact buttons are available for data collection. Furthermore slipped sutures, which act as foreign bodies in uncontrollable locations, no longer confound adhesion formation to the remaining buttons.

The extent of adhesion induction through electrocoagulation and suturing in an experimental rat study

To investigate the effect of three types of peritoneal trauma occurring during surgery (high-frequency bipolar current, suturing, and mechanical damage) on postoperative adhesion formation in a rodent animal model. Randomized, controlled experimental trial in an in vitro animal model. Laboratory facilities of a university department of obstetrics and gynecology. Thirty-five female Wistar rats. Bilateral experimental lesions were created on the abdominal wall in every animal. The effect of minimal electrocoagulation was examined by creating lesions (n = 14) through sweeps of a bipolar forceps with a duration of 1 second and standardized pressure. For extensive electrocoagulation standardized lesions (n = 14) were created using sweeps of a duration of 3 seconds and three times more pressure. For mechanical trauma, standardized lesions (n = 14) were created by denuding the peritoneum mechanically. To study the additive effect of suturing, experimental lesions were created by suturing plus minimal electrocoagulation (n = 14) or mechanical denuding (n = 14). Adhesion incidence, quantity, and quality of the resulting adhesions were scored 14 days postoperatively. Adhesions were studied histopathologically. Mechanical denuding of the peritoneum did not result in adhesion formation. After minimal electrocoagulation, mean adhesion quantity of the traumatized area averaged 0%. This contrasted with extensive electrocoagulation, where there was 50% adhesion. Additional suturing increased mean adhesion quantity to 73% and 64% for superficial electrocoagulation and mechanical denuding, respectively. We conclude that superficial trauma limited mostly to the parietal peritoneum may be a negligible factor in adhesion formation in this model. This appears to be irrespective of the mode of trauma. However, additional trauma to the underlying tissues, either by deeper electrocoagulation or suturing, leads to significantly increased adhesion formation. These data also show that there is a spectrum of electrocoagulation trauma at the lower end of which there is little adhesion formation.

120-Day Comparative Analysis of Adhesion Grade and Quantity, Mesh Contraction, and Tissue Response to a Novel Omega-3 Fatty Acid Bioabsorbable Barrier Macroporous Mesh After Intraperitoneal Placement

This study aimed to evaluate adhesion formation, mesh contraction, and tissue response to an omega-3 fatty acid barrier-coated lightweight polypropylene mesh (C-Qur) after intra-abdominal placement, and compare these properties to those of other commercially available meshes. After randomization, 3 x 3 cm pieces of Atrium C-Qur, Mesh ProLite Ultra, Composix, Parietex, Proceed, Sepramesh, and DualMesh were sewn to the intact peritoneum on either side of a midline incision in 41 New Zealand white rabbits. Necropsy was performed at 120 days, and explants were evaluated for adhesion grade, adhesion amount, and mesh contraction. Histologic evaluation included extent of capsule formation, abdominal wall tissue ingrowth, degrees of inflammation and vascularization of the surrounding tissue, and the presence of mesothelialization. Results. There were no significant differences between the C-Qur mesh and the commercially available meshes tested with regard to adhesion grade or amount, although percentage adhesion coverage for the C-Qur mesh was much less than for Composix and Proceed. The C-Qur mesh contracted less than all meshes, significantly less (P < .05) than DualMesh or Proceed. DualMesh exhibited the greatest amount of capsule formation and inflammation on its parietal side as compared with the other meshes. Placing lightweight polypropylene mesh with an omega-3 fatty acid barrier coating intraperitoneally results in more favorable adhesion characteristics compared with Composix and Proceed meshes at 120-day explantation after intraperitoneal placement. The minimal amount of contraction and favorable tissue response in comparison to other commercially available meshes makes C-Qur mesh a practical alternative for laparoscopic and open ventral hernia repair.

Fabrication of a micro-spherical tool in EDM combined with Ni-diamond co-deposition

This paper demonstrates a novel fabrication process using electro-discharge-machining (EDM) combined with co-deposited Ni-diamond composites to build a unique micro-spherical diamond tool. A micro tool is made by a hybrid process including wire electro-discharge grinding, EDM spherical forming, electrochemical machining and co-deposition. Tungsten carbide material is used as the tool substrate. The influence of EDM spherical forming and co-deposition parameters on the tool geometry is presented. The experimental result shows a unique micro-spherical diamond tool can be successfully built with suitable spherical forming parameters that are a peak current of 3 A, pulse duration of 40 µs and spindle rotational speed of 0 rpm in the air, and in Ni-diamond co-deposition are a current density of 7 A dm−2, diamond particle size of 3 µm, diamond particle concentration of 10 g l−1 and rotational speed of 15 rpm. When using this method, the micro tool has a better geometric shape, uniform particle distribution and suitable particle adhesion quantity. The tool is tested to machine a mold provided with a micro-spherical cavity in a high nickel alloy.

Fabrication of a micro-tool in micro-EDM combined with co-deposited Ni–SiC composites for micro-hole machining

This paper presents an in situ process using a micro-tool in micro-electro-discharge-machining combined with co-deposited Ni–SiC composites to drill and finish micro-holes. During the machining process, a micro-tool is fabricated by wire electro-discharge grinding and electrodeposition. The experimental result shows that the suitable parameters obtained for fabricating micro-tools for Ni–SiC composite coatings are a current density of 7 A dm−2, positive ring hole diameter of 5 mm, SiC particle size of 4 µm, SiC particle concentration of 10 g l−1, rotational speed of 15 rpm and surfactant cetyltrimethylammonium bromide concentration of 150 ppm. When using this method, the micro-tool is provided with a smooth Ni layer, uniform particle distribution and suitable particle adhesion quantity. Then, circular micro-holes are machined in high nickel alloy. Scanning electron microscopy micrographs and atomic force microscopy measurements show that micro-grinding can improve the surface roughness from 1.47 µm Rmax to 0.462 µm Rmax.

Biofilm adhesion and microbially influenced corrosion of SUS304 welds exposed to dam water

Microbially influenced corrosion (MIC) of stainless steel welds has been confirmed not only in natural sea water but also in fresh water recently. In this study, four kinds of SUS304 test coupons, like as base metal, as welded by GTAW without filler metal, as welded by GTAW with filler metal and polished after welding by GTAW, have been prepared. These test coupons have been exposed to the dam water, which caused the MIC failure on the SUS304 piping in the last few years, for 550 days in order to investigate the relation between the adhesion of biofilms and MIC. Visual inspection, measuring of adherent bacteria, proteins and corrosion potential have been executed on the immersed test coupons for each exposure times of 170, 420 and 550 days. The adhesion quantity of biofilms on the test coupons exposed for 170 and 550 days have increased much more than that on the test coupons exposed for 420 days. The effect on the adhesion of biofilms based on the difference of the surface treatments between polishing and as welded has not been confirmed. The ennoblement of the corrosion potential has a connection with not only the adhesion of biofilms but also algae and sedimentation. Furthermore, all test coupons have been observed by SEM. No corrosion pits has been observed on any test coupons of the base metal. On the other hand, some corrosion pits has been confirmed on the test coupons of welds regardless of reinforcement or oxide scale in this study.

A comparison of the shear bond strength of a resin cement and two orthodontic resin adhesive systems.

The object of this study was to compare the shear bond strength and the quantity of adhesive remaining on the tooth after the debonding of brackets bonded with two light-cured orthodontic resin adhesive systems (Transbond XT and Light-Bond) and a dual-cured resin cement (RelyX Unicem). Seventy-five premolars were divided into three groups. In each group, brackets were bonded with one of the adhesives according to the manufacturer's instructions. Shear bond strength was measured using a universal test machine at a crosshead speed of one mm/min, and adhesive remnant was quantified using image analysis equipment. Our results showed that the resin cement produced significantly lower bond strength than the two orthodontic resin adhesive systems. It was also observed that the bond strength produced by Light-Bond was significantly greater than that of Transbond XT. RelyX left significantly less remnant adhesive than Transbond XT and Light-Bond. Between the two orthodontic systems, Light-Bond left significantly less adhesive on the tooth than Transbond XT.

ダム貯水におけるＳＵＳ３０４溶接部の生物皮膜付着と微生物腐食

Microbially influenced corrosion (MIC) of stainless steel welds has been confirmed not only in natural sea water but also in fresh water recently. In this study, four kinds of SUS304 test coupons, like as base metal, as welded by GTAW without filler metal, as welded by GTAW with filler metal and polished after welding by GTAW, have been prepared. These test coupons have been exposed to the dam water, which caused the MIC failure on the SUS304 piping in the last few years, for 550 days in order to investigate the relation between the adhesion of biofilms and MIC. Visual inspection, measuring of adherent bacteria, proteins and corrosion potential have been executed on the immersed test coupons for each exposure times of 170, 420 and 550 days. The adhesion quantity of biofilms on the test coupons exposed for 170 and 550 days have increased much more than that on the test coupons exposed for 420 days. The effect on the adhesion of biofilms based on the difference of the surface treatments between polishing and as welded has not been confirmed. The ennoblement of the corrosion potential has a connection with not only the adhesion of biofilms but also algae and sedimentation. Furthermore, all test coupons have been observed by SEM. No corrosion pits has been observed on any test coupons of the base metal. On the other hand, some corrosion pits has been confirmed on the test coupons of welds regardless of reinforcement or oxide scale in this study.

Twelve elastic constants of Betula platyphylla Suk

Wood elastic constants are needed to describe the elastic behaviors of wood and be taken as an important design parameter for wood-based composite materials and structural materials. This paper clarified the relationships between compliance coefficients and engineering elastic constants combined with orthotropic properties of wood, and twelve elastic constants of Betula platyphylla Suk. were measured by electrical strain gauges. Spreading the adhesive quantity cannot be excessive or too little when the strain flakes were glued. If excessive, the glue layer was too thick which would influence the strain flakes’ performance, and if too little, glues plastered were not firm, which could not accurately transmit the strain. Wood as an orthotropic material, its modulus of elasticity and poisson’s ratios are related by two formulas: μ ij/Ei=µji/Ej and μ ij 0.95) between the reciprocal of elastic modulus MOE−1 and the square of the ratio of depth to length (h/l)2, which indicate that shear modulus values measured were reliable by three point bending experiment.

Recombinant tissue plasminogen activator reduces adhesion formation in a rabbit uterine horn model

To evaluate the potential benefit of recombinant tissue plasminogen activator (rt-PA) as an agent for reducing postoperative adhesions, a rabbit uterine horn model was studied. Fifty-five rabbits underwent laparotomy, at which time the uterus was abraded with scalpel and a thermal injury was induced with electrocautery. Before abdominal closure, rt-PA was applied topically in various dosages. Adhesions were evaluated at a second laparotomy performed 2 weeks later. Treatment significantly reduced both adhesion quantity (P less than 0.001) and adhesion density (P less than 0.001). In the second phase of the study, the efficacy of rt-PA as an adjunct to surgical adhesiolysis was investigated. Again, a dose-related treatment effect was observed (P less than 0.001). No wound healing or bleeding complications were seen.

Characterization of Worker Exposures to Methylene Chloride Resulting from Application of Aerosol Glue in the Asbestos Abatement Industry

Abstract Adhesives containing large percentages of methylene chloride are commonly utilized in the asbestos abatement industry. The adhesive is used to seal polyethylene sheeting to the underlying surfaces, which in turn is used to contain the work area. When completely contained, the work area is essentially a confined space. During subsequent asbestos removal procedures, High Efficiency Particulate Air filter (HEPA)-equipped exhaust systems provide dilution ventilation to the work area, exhausting 1000 to 2000 cubic feet of air per minute per machine. This study characterizes worker exposure levels to methylene chloride when applying these adhesives during the construction of asbestos abatement containments. Personal samples were collected with both 3M organic vapor monitors and standard SKC charcoal tubes. Analysis of the sampling media was conducted by gas chromatography according to NIOSH Method 1005. Exposure periods, ranging from four to six hours, corresponded to a personal time-weighted average (TWA) of 0.09 to 270 ppm. This corresponded to an eight-hour TWA range from 0.06 to 140 ppm, respectively. Short-term exposure limits (STEL), 15 minutes in duration, ranged in concentration from non-detectable to 1294 ppm. Exposure concentrations greatly varied depending upon dilution ventilation, exposure period, adhesive quantity, and room volume. Sample results revealed that use of large quantities of adhesive in a confined area can result in high concentrations of methylene chloride. It is recommended that the HEPA-equipped exhaust systems, primarily designed to control airborne asbestos fiber levels during subsequent removal procedures, be utilized to provide dilution ventilation to the work area when applying these adhesives. It is a current Environmental Protection Agency and Occupational Safety and Health Administration recommendation to start the HEPA-equipped exhaust systems after the work area is completely sealed off and the decontamination unit has been constructed. If these systems are activated at the beginning of the preparation phase, they will create dilution ventilation that can decrease methylene chloride concentrations by a minimum of fourfold. In addition, air purifying respirators equipped with organic vapor cartridges or supplied air respirators should be worn by the workers to reduce their exposure levels even more. Finally, the aerosol manufacturers should substitute the methylene chloride in these products with a suitable, less toxic replacement.

Quantitative analysis of rat brain neurons developing in primary cultures. II. Changes in the distribution of N-CAM associated to neuronal cell surfaces

Cultured rat fetal brain cells underwent morphological differentiation, as quantitatively described in the companion paper. In the same system, biochemical and immunolabeling studies were performed to analyze the developmental changes in neural cell adhesion molecule (N-CAM) distribution and quantity at the cell surface of neurons. The cell surface-associated N-CAM, related to the culture protein content, remained stable during the two-week period under study, as demonstrated by 125I-protein A binding assays. Immunogold labeling experiments, both in transmission and scanning electron microscopy, indicated a dramatic decrease in N-CAM site density in each membrane compartment, perikarya and neurites. This temporal variation of N-CAM distribution was not accompanied by differences in N-CAM site density between these two membrane compartments. On the other hand, individual perikarya, observed in scanning electron microscopy, showed various levels of labeling. In addition, immunoblot experiments demonstrated the absence of chemical modulation of N-CAM during the period under study, since the high molecular weight (embryonic) form remained dominant. Moreover, an increase in the total N-CAM amount was detected, contrasting with the stable quantity of cell surface-associated N-CAM. This suggested the existence of an N-CAM intracellular pool in cultured neurons. Finally, since the neurite membrane surface area increased 9-fold (companion paper) and since only a 5-fold decrease in N-CAM site density was observed in this compartment, N-CAM supply to neurite membranes was postulated.