Short-term Contact Research Articles

Weibull statistics of lap-shear strength development at partially self-healed polymer-polymer interfaces: a short-term contact

Weibull statistics of lap-shear strength development at partially self-healed polymer-polymer interfaces: a short-term contact

Postoperative time dependent tibiofemoral articular cartilage contact kinematics during step-up after ACL reconstruction

This study was to investigate the in vivo tibiofemoral cartilage contact locations before and after anterior cruciate ligament (ACL) reconstruction at 6 and 36 months.Ten patients with unilateral ACL injury were included. A step-up motion was analyzed using a combined magnetic resonance modeling and dual fluoroscopic imaging techniques. The preoperative (i.e. ACL deficient and healthy contralateral) and postoperative cartilage contact locations at 6 and 36 months were analyzed.Similar patterns of the cartilage contact locations during the step-up motion were found for the preoperative and postoperative knee states as compared to the preoperative healthy contralateral side. At the end of step-up motion, the medial contact locations at postoperative 36 months were more anterior when compared to the preoperative healthy contralateral (p=0.02) and 6 months postoperative knee states (p=0.01). The changes of the cartilage contact locations at 36 months after ACL reconstruction compared to the healthy contralateral side were strongly correlated with the changes at 6 months postoperatively.This study showed that the tibiofemoral cartilage contact locations of the knee changes with time after ACL reconstruction, implying an ongoing recovery process within the 36 months after the surgery. There could be an association between the short-term (6 months) and longer-term (36 months) contact kinematics after ACL reconstruction. Future studies need to investigate the intrinsic relationship between knee kinematics at different times after ACL reconstruction.

Dike-induced thermal alteration of the Springfield Coal Member (Pennsylvanian) and adjacent clastic rocks, Illinois Basin, USA

A basaltic dike intrusion caused a short-term and short-distance contact aureole in the vitrinite-rich Springfield Coal Member of the Carbondale Formation (Pennsylvanian) and in the underlying paleosol and overlying black shale in the Illinois Basin. Parallel series of samples from all three horizons were analyzed for vitrinite reflectance (Ro, %) and other parameters to evaluate the lateral extension of the thermal aureole. Ro values in the porous and fluid-permeable coal increase from a background value of ~0.66% at ≥4.0m distance from the dike to more than 5.0% at the intrusive contact. Ro values in the underlying paleosol increase from a background of ~0.65% at ≥3m distance to 1.74% at the dike contact. In contrast, roof rock shale close to the contact had a higher Ro value than the paleosol (Ro=2.56%). These differences cannot be explained by thermal conductivity of heat alone, or the coal having lower thermal conductivity would show lower vitrinite reflectance values. Apparently, the coal having much higher Ro values experienced enhanced lateral convective heat transfer in comparison to the denser and less permeable, but more conductive, rocks in the paleosol and overlying black shale. The advection of relatively cold fluid in the lower part of the coal seam streaming towards the dike may have provided cooling for floor rock close to the coal near the contact. In contrast, roof rock close to the contact had a higher Ro value than the paleosol (Ro=2.56%) in the absence of cooling.

Formation and composition of adsorbates on hydrophobic carbon surfaces from aqueous laccase-maltodextrin mixture suspension

A robust procedure for the surface bio-functionalization of carbon surfaces was developed. It consists on the modification of carbon materials in contact with an aqueous suspension of the enzyme laccase from Trametes versicolor and the lyophilization agent maltodextrin, with the pH value adjusted close to the isoelectric point of the enzyme. We report in-situ investigations applying Quartz Crystal Microbalance with Dissipation (QCM-D) for carbon-coated sensor surfaces and, moreover, ex-situ measurements with static contact angle measurements, X-ray Photoelectron Spectroscopy (XPS) and Scanning Force Microscopy (SFM) for smooth Highly Oriented Pyrolytic Graphite (HOPG) substrates, for contact times between the enzyme formulation and the carbon material surface ranging from 20s to 24h. QCM-D studies reveals the formation of rigid layer of biomaterial, a few nanometers thin, which shows a strongly improved wettability of the substrate surface upon contact angle measurements. Following spectroscopic characterization, these layers are composed of mixtures of laccase and maltodextrin. The formation of these adsorbates is attributed to attractive interactions between laccase, the maltodextrin-based lyophilization agent and the hydrophobic carbon surfaces; a short-term contact between the aqueous laccase mixture suspension and HOPG surfaces is shown to merely result in de-wetting patterns influencing the results of contact angle measurements. The new enzyme-based surface modification of carbon-based materials is suggested to be applicable for the improvement of not only the wettability of low energy substrate surfaces with fluid formulations like coatings or adhesives, but also their adhesion in contact with hardened polymers.

Influence of the surface properties on bactericidal and fungicidal activity of magnetron sputtered Ti–Ag and Nb–Ag thin films

In this study the comparative investigations of structural, surface and bactericidal properties of Ti–Ag and Nb–Ag thin films have been carried out. Ti–Ag and Nb–Ag coatings were deposited on silicon and fused silica substrates by magnetron co-sputtering method using innovative multi-target apparatus. The physicochemical properties of prepared thin films were examined with the aid of X-ray diffraction, grazing incidence X-ray diffraction, scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy methods. Moreover, the wettability of the surface was determined. It was found that both, Ti–Ag and Nb–Ag thin films were nanocrystalline. In the case of Ag–Ti film presence of AgTi3 and Ag phases was identified, while in the structure of Nb–Ag only silver occurred in a crystal form. In both cases the average size of crystallites was ca. 11nm. Moreover, according to scanning electron microscopy and atomic force microscopy investigations the surface of Nb–Ag thin films was covered with Ag-agglomerates, while Ti–Ag surface was smooth and devoid of silver particles. Studies of biological activity of deposited coatings in contact with Bacillus subtilis, Pseudomonas aeruginosa, Enterococcus hirae, Klebisiella pneumoniae, Escherichia coli, Staphylococcus aureus and Candida albicans were performed. It was found that prepared coatings were bactericidal and fungicidal even in a short term-contact, i.e. after 2h.

Abstract B055: The impact of rapamycin and tacrolimus treatment on resident CD8+ T-cell populations in cutaneous squamous cell carcinoma

Abstract Organ transplant recipients have an increased risk of non-melanoma skin cancer (NMSC) development. Immunosuppressive agents, given to these patients to prevent organ rejection, are widely recognized to play a key role in the increased incidence of malignancy. However, different immunosuppressive agents, such as rapamycin and tacrolimus, which both prevent organ rejection, convey different risks of tumor formation. Using a UV-induced murine model of squamous cell carcinoma (SCC); HPV38 E6E7, we aim to determine whether these discrepancies are due to differences in the mechanism of immune suppression, in contrast to the much discussed direct effects of these drugs on tumor cells (i.e. immune-independent). Using customized rapamycin- and tacrolimus-incorporated feed to allow long-term administration, clinically relevant whole blood drug concentrations were obtained and validated using LC-MS/MS. Both systemic and local immunosuppression was functionally determined via adoptively transferred transgenic T-cell assay and skin allograft rejection profile, respectively. Notably however, preliminary data suggests phenotypic and functional differences of skin-residing T-cell subpopulations may exist when mice are treated with either rapamycin or tacrolimus, alluding to their potential role in the pathogenesis of NMSC. Short-term contact hypersensitivity responses (CHS) to OVA were abrogated in both rapamycin and tacrolimus-treated mice. However, prolonging the challenge phase enhanced the long-term CHS response in rapamycin-treated but not in tacrolimus-treated mice compared to normal feed controls. This enhanced response was correlated with an increased number of effector memory CD8+ T-cell population in the challenged ear skin. Using established chronic UV dosing schedules for SCC development in HPV38 E6E7 mice, tumor samples along with surrounding UV-exposed skin and fur-covered UV-protected skin samples were analyzed with FACs under the influence of these drugs. Preliminary data suggests that the formation of resident-memory CD8+ T-cells may be favored when treated with rapamycin, as higher percentages of CD8+ T-cells were present in the lesions of rapamycin-treated mice compared to tacrolimus and controls. In addition, LC-MS/MS analysis indicated that the concentration of rapamycin in the skin was significantly lower when compared to tacrolimus, whilst clinically relevant immunosuppressive concentrations of both drugs were maintained in the blood and kidneys. Through this project, we will expand our knowledge base regarding mechanisms of SCC formation in immunosuppressed patients. Citation Format: Ji-Won Jung, Paul J. Taylor, Fiona Simpson, Ian H. Frazer, James W. Wells. The impact of rapamycin and tacrolimus treatment on resident CD8+ T-cell populations in cutaneous squamous cell carcinoma. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B055.

Morphological changes in the conjunctiva, episclera and sclera following short-term miniscleral contact lens wear in rigid lens neophytes.

To quantify the influence of short-term wear of miniscleral contact lenses on the morphology of the corneo-scleral limbus, the conjunctiva, episclera and sclera. OCT images of the anterior eye were captured before, immediately following 3h of wear and then 3h after removal of a miniscleral contact lens for 10 young (27 ± 5 years) healthy participants (neophyte rigid lens wearers). The region of analysis encompassed 1mm anterior, to 3.5mm posterior to the scleral spur. Natural diurnal variations in thickness were measured on a separate day and compensated for in subsequent analyses. Following 3h of lens wear, statistically significant tissue thinning was observed across all quadrants, with a mean decrease in thickness of -24.1 ± 3.6 μm (p<0.001), which diminished, but did not return to baseline 3h after lens removal (-16.9 ± 1.9 μm, p<0.001). The largest tissue compression was observed in the superior quadrant (-49.9 ± 8.5 μm, p<0.01) and in the annular zone 1.5mm from the scleral spur (-48.2 ± 5.7 μm), corresponding to the approximate edge of the lens landing zone. Compression of the conjunctiva/episclera accounted for about 70% of the changes. Optimal fitting miniscleral contact lenses worn for three hours resulted in significant tissue compression in young healthy eyes, with the greatest thinning observed superiorly, potentially due to the additional force of the eyelid, with a partial recovery of compression 3h after lens removal. Most of the morphological changes occur in the conjunctiva/episclera layers.

Influence of Cu-Ti thin film surface properties on antimicrobial activity and viability of living cells.

The paper describes properties of thin-film coatings based on copper and titanium. Thin films were prepared by co-sputtering of Cu and Ti targets in argon plasma. Deposited coatings consist of 90at.% of Cu and 10at.% of Ti. Characterization of the film was made on the basis of investigations of microstructure and physicochemical properties of the surface. Methods such as scanning electron microscopy, x-ray microanalysis, x-ray diffraction, x-ray photoelectron spectroscopy, atomic force microscopy, optical profilometry and wettability measurements were used to assess the properties of deposited thin films. An impact of Cu-Ti coating on the growth of selected bacteria and viability of the living cells (line L929, NCTC clone 929) was described in relation to the structure, surface state and wettability of the film. It was found that as-deposited films were amorphous. However, in such surroundings the nanocrystalline grains of 10-15nm and 25-35nm size were present. High surface active area with a roughness of 8.9nm, had an effect on receiving relatively high water contact angle value (74.1°). Such wettability may promote cell adhesion and result in an increase of the probability of copper ion transfer from the film surface into the cell. Thin films revealed bactericidal and fungicidal effects even in short term-contact. High activity of prepared films was directly related to high amount (ca. 51 %) of copper ions at 1+ state as x-ray photoelectron spectroscopy results have shown.

The Benefits of Mouse Keeping—an Empirical Study on Students’ Flow and Intrinsic Motivation in Biology Lessons

Contact with living animals is an exceptional possibility within biology education to facilitate an intense immersion into the study topic and even allow for a flow experience (Csikszentmihalyi 2000). Further, it might affect the perceptions of the students’ basic needs for autonomy and competence and thereby their quality of motivation (Deci and Ryan 1985, 2002). Still, there is little empirical evidence about the duration of the exposure with living animals that is required. We investigated the students’ flow experience, and the students’ motivation, reported retrospectively in three different treatments: lessons involving short-term or long-term contact with living harvest mice and a control group without living animals. Our sample consisted of 156 fifth graders (10.76 years, SD = 0.513). The test instruments were adapted versions of the Flow Short Scale (FSS, Rheinberg et al. 2003) and of the Intrinsic Motivation Inventory (IMI, Ryan 1982). As expected, the control group produced significantly lower scores for both FSS and IMI. In addition, we found a significant difference between students with short-term versus long-term contact. Whereas the flow experience was indistinguishable for all pupils who had contact with living animals, those with long-term experience reported significantly higher intrinsic motivation.

The effects of short-term contact lens-induced hypoxia tried on ourselves

The effects of short-term contact lens-induced hypoxia tried on ourselves

PHARMACOEPIDEMIOLOGY AND THE EFFICACY OF ANTIHYPERTENSIVE TREATMENT IN REAL-LIFE PRACTICE OF THE CARDIOLOGY REFERRAL CLINIC

Arterial hypertension is a disease which leads to severe negative social and economic consequences. Pharmacoepidemiologic studies allow assessment of present situation on high blood pressure (BP) treatment and search of ways of its efficacy improvement. Aim. To study treatment of hypertensive patients who had visited the cardiology referral clinic for the first time and to assess treatment dynamics over the following 6 months with the estimation of its efficacy. Material and methods. The study included two steps. At the first step a primary sample of the study participants was formed out of hypertensive patients who had visited for the first time a cardiologist in one of the Moscow district cardiologic dispensary in 2010 with the further completion of expert cards in accordance with the primary medical documentation (n=1766). At the second step the phone survey was conducted 6 months after the first visit with the completion of special questionnaires (n=1419). Results. Recommendations for antihypertensive treatment given to the cardiologic dispensary patients are in line with the current guidelines, and 6 months after the first visit 91% of the patients had continued antihypertensive treatment. However, the efficacy of BP control turned out to be low: target BP level was only detected in 28.8% of the patients, and 36.7% of the respondents developed hypertensive crises during the 6 months. Conclusion. Despite the follow-up in the referral clinic and the intake of the prescribed drugs the patients revealed low efficacy of BP control. The reasons for this fact require further investigation. Probably, the improvement of BP control requires implementation of special education and motivational techniques as short-term contact with specialists does not lead to high efficacy of antihypertensive treatment.

Effects of sex and reproductive state on interactions between free-roaming domestic dogs.

Free-roaming dogs (Canis familiaris) are common worldwide, often maintaining diseases of domestic pets and wildlife. Management of these dogs is difficult and often involves capture, treatment, neutering and release. Information on the effects of sex and reproductive state on intraspecific contacts and disease transmission is currently lacking, but is vital to improving strategic management of their populations. We assessed the effects of sex and reproductive state on short-term activity patterns and contact rates of free-roaming dogs living in an Australian Indigenous community. Population, social group sizes and rates of contact were estimated from structured observations along walked transects. Simultaneously, GPS telemetry collars were used to track dogs' movements and to quantify the frequency of contacts between individual animals. We estimated that the community's dog population was 326±52, with only 9.8±2.5% confined to a house yard. Short-term activity ranges of dogs varied from 9.2 to 133.7 ha, with males ranging over significantly larger areas than females. Contacts between two or more dogs occurred frequently, with entire females and neutered males accumulating significantly more contacts than spayed females or entire males. This indicates that sex and reproductive status are potentially important to epidemiology, but the effect of these differential contact rates on disease transmission requires further investigation. The observed combination of unrestrained dogs and high contact rates suggest that contagious disease would likely spread rapidly through the population. Pro-active management of dog populations and targeted education programs could help reduce the risks associated with disease spread.

Prevention of Neointimal Formation After Angioplasty Using Nuclear Factor-κB Decoy Oligodeoxynucleotide-Coated Balloon Catheter in Rabbit Model

Despite the advent of drug-eluting stents, restenosis after endovascular intervention is still a major limitation in the treatment of cardiovascular disease. To regulate the multiple biological mechanisms underlying restenosis, we focused on inhibition of an important transcription factor, nuclear factor-kappaB (NFκB), using a decoy strategy. For site-specific application of NFκB decoy oligodeoxynucleotides into target vessels during angioplasty, we developed a balloon catheter-based delivery system combined with biocompatible nanoparticles as oligodeoxynucleotides carriers. To clarify the therapeutic effect at the site of neointima, balloon angioplasty of the rabbit carotid arteries was performed at 4 weeks after initial endothelial denudation. This delivery system exhibited successful transfer of fluorescence-labeled nanospheres into the neointima in short-term contact with target vessels, and fluorescence could be detected ≥1 week after angioplasty. Consistently, local application of NFκB decoy oligodeoxynucleotides -loaded nanospheres resulted in significant inhibition of neointimal formation, associated with inhibition of NFκB binding activity in the injured arteries. The therapeutic effects were caused by inhibition of macrophage recruitment through the suppression of monocyte chemoattractant protein-1, vascular cell adhesion molecule-1, and CC chemokine ligand 4 expression and inhibition of vascular smooth muscle cell growth via a decrease in the expression of cyclin A and proliferating cell nuclear antigen. Importantly, application of NFκB nanospheres accelerated restoration of the endothelial cell monolayer, associated with enhanced expression of phosphorylated Bcl-2 in endothelial cells. A drug-coated balloon catheter using NFκB decoy oligodeoxynucleotides significantly inhibited the development of neointimal hyperplasia in rabbits. The present study indicates the possibility of a novel therapeutic option to prevent restenosis after angioplasty.

Wood impregnation of yeast lees for winemaking

This study develops a new method to produce more complex wines by means of an indirect diffusion of wood aromas from yeast cell-walls. An exogenous lyophilized biomass was macerated with an ethanol wood extract solution and subsequently dried. Different times were used for the adsorption of polyphenols and volatile compounds to the yeast cell-walls.The analysis of polyphenols and volatile compounds (by HPLC/DAD and GC–MS, respectively) demonstrate that the adsorption/diffusion of these compounds from the wood to the yeast takes place. Red wines were also aged with Saccharomyces cerevisiae lees that had been impregnated with wood aromas and subsequently dried. Four different types of wood were used: chestnut, cherry, acacia and oak. Large differences were observed between the woods studied with regards to their volatile and polyphenolic profiles.Sensory evaluations confirmed large differences even with short-term contact between the wines and the lees, showing that the method could be of interest for red wine making. In addition, the results demonstrate the potential of using woods other than oak in cooperage.

Use of reflectance near-infrared spectroscopy to investigate the effects of daily moisturizer application on skin optical response and barrier function.

A number of noninvasive techniques and instruments have emerged over the years allowing much progress toward clarifying the structure and function of human skin and studying the effects of various applied substances. All of this research has provided great insight into the interactions between skin and various products through quantitative and qualitative measurements. Such methods include near-infrared spectroscopy (NIRS), a technique which has gained popularity over the years and has often been employed to accurately determine the moisture levels and water content of skin based on its sensitivity to hydrogen bonding. NIRS has also been applied in many studies to report the efficacy of moisturizing products and assess their benefits to the skin. However, many of these studies have reported an increase in skin water content following moisturizer application while some have challenged the benefits of long-term moisturizer use, particularly on normal skin, and even suggested that it can increase the skin's susceptibility to irritants. This paper reports the results of a pilot in vivo study carried out on the skin of 20 healthy volunteers, categorized into groups depending on their skin type and frequency of moisturizer use, in order to investigate the optical response of human skin after direct short-term contact with water followed by application of a moisturizer. The measurements were obtained using a highly advanced spectrophotometer in the region of 900 to 2100 nm equipped with a customized reflectance fiber optic handheld probe. Scatter graphs of group results and second derivative spectra have shown an interesting pattern between frequent users of moisturizers and individuals who do not use moisturizers, suggesting that long-term daily moisturization may have an effect on skin barrier function. The results also raise some questions regarding the optical characteristics of different skin types, as well as the varying response between different water bands in the NIR region. Future work will focus on gaining more knowledge about these subjects and obtaining results from a larger population, as well as performing statistical analysis through regression methods in order to further improve optical skin measurements.

The effect of 5% sodium hypochlorite, 17% EDTA and triphala on two different rotary Ni-Ti instruments: An AFM and EDS analysis.

Aim:To use Atomic Force Microscope and Energy Dispersive X-ray Spectroscopy to evaluate the effect of 5% NaOCl, 17% EDTA and triphala on ProTaper and iRaCe rotary Ni-Ti instruments.Methodology:A total of eight Ni-Ti rotary files, four files each of ProTaper - S2 (Dentsply) and iRaCe - R3 (FKG DENTAIRE) were used. Three out of four files each from ProTaper and iRaCe were immersed in 5% NaOCl, 17% EDTA and Triphala separately for five minutes. The Roughness average (Ra), Root Mean Square (RMS) and Mean Height of Roughness Profile Elements (Rc) of the scanned profiles were then recorded using AFM and the elemental composition was evaluated with EDS. Data were analyzed by Student's t test, One Way ANOVA and Duncan's Multiple Range Test.Results:Topographic irregularities at the nanometric scale were observed for all files. Files immersed in EDTA and NaOCl showed highly significant surface roughness than untreated files.Conclusion:Short-term contact with 17% EDTA and 5% NaOCl can cause significant surface deterioration of ProTaper and iRaCe rotary NiTi files. AFM proves to be a suitable method for evaluating the instrument surface.

Scientific Opinion on the safety evaluation of the substance, 1,3,5‐tris(2,2‐dimethylpropanamido)benzene, CAS No. 745070‐61‐5, for use in food contact materials

This scientific opinion of EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety evaluation of the additive 1,3,5-tris(2,2-dimethylpropanamido)benzene with the CAS No. 745070-61-5, the Ref. No 95420, the FCM Substance No 784, for use as a nucleating agent/clarifier at a maximum use level of 250 mg/kg in polyprolylene (PP). Final articles are intended to be used in contact with all type of foods for short term contact (1 hour) at temperatures up to 100 ºC and/or for long term storage at ambient temperature or below. Specific migration of the substance into 3 % acetic acid, 10 % ethanol and olive oil, was measured to be up to 48 µg/kg, 79 µg/kg and 94 µg/kg, respectively. In vitro and in vivo genotoxicity tests showed no evidence for a genotoxic potential of the substance. A 90-day dietary toxicity study in Wistar rats showed no effects at any dose and the NOAEL was considered to be 961 mg/kg bw/day in males and 1104 mg/kg bw/day in females or higher. Therefore, the CEF Panel concluded that the substance 1,3,5-tris(2,2-dimethylpropanamido)benzene does not raise a safety concern for the consumer if it is used in polyolefins and the migration does not exceed 5 mg/kg food.

Dermal Uptake of 18 Dilute Aqueous Chemicals: In Vivo Disappearance‐Method Measures Greatly Exceed In Vitro‐Based Predictions

Average rates of total dermal uptake (Kup ) from short-term (e.g., bathing) contact with dilute aqueous organic chemicals (DAOCs) are typically estimated from steady-state in vitro diffusion-cell measures of chemical permeability (Kp ) through skin into receptor solution. Widely used ("PCR-vitro") methods estimate Kup by applying diffusion theory to increase Kp predictions made by a physico-chemical regression (PCR) model that was fit to a large set of Kp measures. Here, Kup predictions for 18 DAOCs made by three PCR-vitro models (EPA, NIOSH, and MH) were compared to previous in vivo measures obtained by methods unlikely to underestimate Kup . A new PCR model fit to all 18 measures is accurate to within approximately threefold (r = 0.91, p < 10(-5) ), but the PCR-vitro predictions (r > 0.63) all tend to underestimate the Kup measures by mean factors (UF, and p value for testing UF = 1) of 10 (EPA, p < 10(-6) ), 11 (NIOSH, p < 10(-8) ), and 6.2 (MH, p = 0.018). For all three PCR-vitro models, log(UF) correlates negatively with molecular weight (r(2) = 0.31 to 0.84, p = 0.017 to < 10(-6) ) but not with log(vapor pressure) as an additional predictor (p > 0.05), so vapor pressure appears not to explain the significant in vivo/PCR-vitro discrepancy. Until this discrepancy is explained, careful in vivo measures of Kup should be obtained for more chemicals, the expanded in vivo database should be compared to in vitro-based predictions, and in vivo data should be considered in assessing aqueous dermal exposure and its uncertainty.

Anti-platelet and tissue engineering approaches to biomaterial blood compatibilization: how well have these been translated into the clinic?

In this article, we provide an update on the various approaches to "blood compatibilization", and include both passive and active approaches to compatibilizing biomaterials in contact with blood. Broadly speaking, the surface modification approaches involved either repel platelets or attract endothelial cells. For platelet-repelling surfaces, heparin immobilization seems to be the most successful approach. At least two such surfaces have been approved by the health authorities in various countries for applications involving short-term contact with blood. For active endothelialization, ex vivo seeding with autologous cells has been translated into the clinic, while selective endothelial cell capture is a promising approach. In spite of over 30years of research in this area, a truly intrinsically non-clotting surface has not been developed yet; certain promising avenues have been indicated by the research, which we will critically assess here.

Corneal changes following short-term rigid contact lens wear

The aim of this cross-over study was to investigate the changes in corneal thickness, anterior and posterior corneal topography, corneal refractive power and ocular wavefront aberrations, following the short term use of rigid contact lenses. Fourteen participants wore 4 different types of contact lenses (RGP lenses of 9.5mm and 10.5mm diameter, and for comparison a PMMA lens of 9.5mm diameter and a soft silicone hydrogel lens) on 4 different days for a period of 8h on each day. Measures were collected before and after contact lens wear and additionally on a baseline day. Anterior corneal curvature generally showed a flattening with both of the RGP lenses and a steepening with the PMMA lens. A significant negative correlation was found between the change in corneal swelling and central and peripheral posterior corneal curvature (all p ≤ 0.001). RGP contact lenses caused a significant decrease in corneal refractive power (hyperopic shift) of approximately 0.5D. The PMMA contact lenses caused the greatest corneal swelling in both the central (27.92 ± 15.49 μm, p<0.001) and peripheral (17.78 ± 12.11 μm, p=0.001) corneal regions, a significant flattening of the posterior cornea and an increase in ocular aberrations (all p ≤ 0.05). The corneal swelling associated with RGP lenses was relatively minor, but there was slight central corneal flattening and a clinically significant hyperopic change in corneal refractive power after the first day of lens wear. The PMMA contact lenses resulted in significant corneal swelling and reduced optical performance of the cornea.