Organic modification of layered silicates for use as barrier pigments in coating systems

Functional coatings and the barrier pigments they contain are an indispensable part of corrosion or product protection. The frequently used layered silicates in their pure form often do not achieve a sufficient protection of the components or products. The barrier effect of the silicates can be significantly improved through targeted organic modification. The general use of commercial (unmodified) silicates leads to an improvement in the barrier of about 20 %. In contrast, the use of modified silicates achieves an improvement of up to 80 % [1], due to the extent of the diffusion path [2]. Decisive for the diffusion path and therefore for the subsequent functionality of the barrier is the exfoliation and orientation of the silicates, which depends on the compatibility with the coating system. Due to the large number of coating systems and the associated binder classes, the silicates should be specifically adapted to the respective polymer by being modified with reactive groups, which represents the main focus of this work. As a first polymer system an epoxy matrix was chosen. Thus, commercial silicates were modified by an epoxy-oligomer matrix based on 1,4-butanediol diglycidyl ether. The produced silicates were examined with the aid of scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The expansion of the layers and the attachment of the organic molecules were investigated using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS)

Skin Disinfection by Plasma-Tissue Interaction: Comparison of the Effectivity of Tissue-Tolerable Plasma and a Standard Antiseptic

Wound healing disorders frequently occur due to biofilm formation on wound surfaces requiring conscientious wound hygiene. Often, the application of conventional liquid antiseptics is not sufficient and sustainable as (1) the borders and the surrounding of chronic wounds frequently consist of sclerotic skin, impeding an effectual penetration of these products, and (2) the hair follicles representing the reservoir for bacterial recolonization of skin surfaces are not affected. Recently, it has been reported that tissue-tolerable plasma (TTP), which is used at a temperature range between 35 and 45°C, likewise has disinfecting properties. In the present study, the effectivity of TTP and a standard liquid antiseptic was compared in vitro on porcine skin. The results revealed that TTP was able to reduce the bacterial load by 94%, although the application of the liquid antiseptic remained superior as it reduced the bacteria by almost 99%. For in vivo application, however, TTP offers several advantages. On the one hand, TTP enables the treatment of sclerotic skin as well, and on the other hand, a sustainable disinfection can be realized as, obviously, also the follicular reservoir is affected by TTP

The effect of high-dose erythropoietin perinatally on retinal function in school-aged children born extremely or very preterm

PURPOSE: To investigate the long-term effects of high-dose recombinant human erythropoietin (rhEPO) administered during the perinatal period on retinal and visual function in children born extremely or very preterm. DESIGN: Randomized, double-blind clinical trial follow-up plus cohort study. METHODS: Setting: Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland. Study population: extremely or very preterm-born children aged 7-15 years, previously randomized to receive either high-dose rhEPO or placebo in the perinatal period. Inclusion criteria: participation in an ongoing neuropediatric study (EpoKids), written informed consent (IC). Exclusion criteria: previous ocular trauma or surgery; retinal or developmental disease unrelated to prematurity. Healthy control (HC) children of comparable age were recruited. Inclusion criteria: term birth, IC. Exclusion criteria: any ocular/visual abnormality, high refractive error. Intervention status (rhEPO/placebo) was unknown to examiners and subjects at examination, with examiners unblinded only after completion of all analyses. Observation procedures: Electroretinography (ERG) was performed with the RETeval device (LKC Technologies, Inc., Gaithersburg MD). Ophthalmological and orthoptic examinations excluded comorbidity in the prematurely born cohort and ocular diseases in the HC group. Main outcome measures: Scotopic and photopic ERG response amplitudes and peak times (6 amplitudes; 6 peak times). Secondary outcomes were habitual visual acuity and color discrimination performance (for descriptive summary only). RESULTS: No differences in ERG parameters between EPO (n=52; 104 eyes) and placebo (n=35; 70 eyes) subgroups were observed (all corrected p>0.05). Two cone system-mediated peak times were slightly slower in the placebo than HC (n=52; 104 eyes) subgroup (coefficient/95% confidence interval (CI) = 0.53/0.21 to 0.85 and 0.36/0.13 to 0.60; p = 0.012 and 0.022); a predominantly rod system-mediated peak time was slightly faster in the EPO than the HC subgroup (coefficient/95% CI = -4.33/-6.88 to -1.78; p = 0.011). Secondary outcomes were comparable across subgroups. CONCLUSIONS: Administration of high-dose rhEPO to infants born extremely or very preterm during the perinatal period has no measurable effects on retinal function in childhood compared to placebo. Premature birth may cause small, likely clinically insignificant effects on retinal function in childhood, which may be partially mitigated by administration of rhEPO during the perinatal period

Dynamics of hydration water in deuterated purple membranes explored by neutron scattering

The function and dynamics of proteins depend on their direct environment, and much evidence has pointed to a strong coupling between water and protein motions. Recently however, neutron scattering measurements on deuterated and natural-abundance purple membrane (PM), hydrated in H2O and D2O, respectively, revealed that membrane and water motions on the ns–ps time scale are not directly coupled below 260 K (Wood et al. in Proc Natl Acad Sci USA 104:18049–18054, 2007). In the initial study, samples with a high level of hydration were measured. Here, we have measured the dynamics of PM and water separately, at a low-hydration level corresponding to the first layer of hydration water only. As in the case of the higher hydration samples previously studied, the dynamics of PM and water display different temperature dependencies, with a transition in the hydration water at 200 K not triggering a transition in the membrane at the same temperature. Furthermore, neutron diffraction experiments were carried out to monitor the lamellar spacing of a flash-cooled deuterated PM stack hydrated in H2O as a function of temperature. At 200 K, a sudden decrease in lamellar spacing indicated the onset of long-range translational water diffusion in the second hydration layer as has already been observed on flash-cooled natural-abundance PM stacks hydrated in D2O (Weik et al. in J Mol Biol 275:632–634, 2005), excluding thus a notable isotope effect. Our results reinforce the notion that membrane-protein dynamics may be less strongly coupled to hydration water motions than the dynamics of soluble proteins

Combination chemotherapy with or without s.c. IL-2 and IFN-α: results of a prospectively randomized trial of the Cooperative Advanced Malignant Melanoma Chemoimmunotherapy Group (ACIMM)

The purpose of this randomized trial was to evaluate the efficacy of combination chemoimmunotherapy compared with chemotherapy alone. A total of 124 patients were randomized to receive intravenous cisplatin (35 mg m−2, days 1–3), carmustine (150 mg m−2, day 1, cycles 1 and 3 only), dacarbacine (220 mg m−2, days 1–3) and oral tamoxifen (20 mg m−2, daily) in combination with (n=64) or without (n=60) sequential subcutaneous IL-2 and IFN-α. In those patients who received sequential immunotherapy, each cycle of chemotherapy was followed by outpatient s.c. IL-2 (10×106 IU m−2, days 3–5, week 4; 5×106 IU m−2, days 1, 3, 5, week 5) and s.c. IFN-α (5×106 IU m−2, day 1, week 4; days 1, 3, 5, week 5). The overall response rate of patients treated with the combination of chemotherapy and IL-2/IFN-α was 34.3% with seven complete responses (10.9%) and 15 partial responses (23.4%). In patients treated with chemotherapy, only, the overall response rate was 29.9% with eight complete responses (13.3%) and 10 partial responses (16.6%). There was no significant difference in median progression free survival (0 months vs 4 months) and in median overall survival (12 months vs 13 months) for combined chemoimmunotherapy and for chemotherapy, respectively

Trueness of CAD/CAM digitization with a desktop scanner – an in vitro study

Desktop scanners are devices for digitization of conventional impressions or gypsum casts by indirect Computer-Aided Design/Computer-Assisted Manufacturing (CAD/CAM) in dentistry. The purpose of this in vitro study was: 1, to investigate whether virtual models produced by the extraoral scanner have the same trueness as sectioned casts; and 2, to assess if digitization with an extraoral scanner influences the surface information

Livestock browsing affects the species composition and structure of cloud forest in the Dhofar Mountains of Oman

Questions: It is frequently reported that overstocking of camels, cattle and goats is degrading the Anogeissus cloud forest, which is endemic to a 200 km stretch of coastal mountains in southern Arabia. However, livestock impacts on the vegetation have not been assessed. Furthermore, we have a limited understanding of the impacts of large-bodied browsing livestock, such as camels, in woodland and forest rangelands. Therefore, in this study, we examine the effects of livestock browsing on the species composition, density, and hytomorphology of woody vegetation in the Anogeissus cloud forests in the Dhofar Mountains of Oman. Location: Data was collected at 30 sites in the Jabal Qamar mountain range in western Dhofar, Oman. Methods: The point-centered quarter method was used to sample the composition, density and structure of woody vegetation. Constrained correspondence analysis was used to quantify the effects of livestock browsing on woody plant species composition, whilst effects on plant density were analysed using mixed effects models. Standardised major axis regression was used to examine differences in height-diameter allometry (stunting) under different stocking rates. Results: Fog density, topographic position and long-term stocking rates were found to be important factors affecting woody species composition. We found lower species diversity and plant density, and higher frequencies of unpalatable species, under higher stocking rates. Juveniles showed a stronger response to stocking rates than adults, and several common species exhibited stunted morphology under high stocking rates. Conclusions: Browsing by large-bodied livestock, such as camels and cattle, can substantially alter the species composition, structure, and phytomorphology of woody vegetation in semi-arid woodlands and forests. Juveniles are particularly susceptible to browsing which alters woody vegetation demography and inhibits regeneration potential. Our results support previous suggestions of overstocking in Dhofar and highlight the importance of swift measures to reduce livestock browsing pressure in the Anogeissus cloud forests