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Electronic devices utilize the foremost advances in technology. In order to make progress we must understand not only the properties of novel materials but also how best to synthesize these materials in an appropriate way so that they can be used in an industrial setting. Transition metal dichalcogenides, specifically molybdenum ditelluride (MoTe2) is a class of 2D material that has been well studied for their semiconducting nature in the 2H phase yet they also have 2 other phases with vastly different properties: 1T’ and 1T. The 1T’ phase has metallic properties. There is a 3rd phase, however, that prior to my work has been largely left unstudied, the 1T phase. This phase is calculated to be semi metallic from its calculated band structure but is also highly unfavorable at room temperature. With this in mind we set out to synthesis this elusive phase via a chemical vapor deposition process by selectively using process gases and varying cooling rates to stabilize the 1T phase at ambient temperatures. Measurements confirm the 1T phase of MoTe2 is in fact semi-metallic. In addition, mixed phase 2H/1T films were synthesized and electronically tested to yield a semiconducting film with significantly improved conductivity that could still be gated for on/off current switching.As copper interconnects decrease in cross-section to below 100 nm in size the resistivity of this, typically, highly conductive metal starts to increase exponentially do to surface and grain boundary scattering of electrons. Quasi-1D Transition metal trichalcogenides, like tantalum triselenide (TaSe3), can have metallic properties. The main issue that is being addressed is that of copper interconnects as they reach their scaling limits. The concentration is 2-fold, 1) develop a growth method/process that could synthesis TaSe3 at temperatures at or lower than 400°C and 2) measure the materials resistivity as a function of decreasing cross-sectional area to see if these highly crystalline transition metal trichalcogenide maintains its bulk resistivity unlike that of copper. Given this momentous task we again set out to develop a chemical vapor deposition process to synthesis TaSe3 using volatilized reagents to help aid in the formation of the crystals at low temperatures. The resistivity of the nanowires grown using this method were tested down to 7nm in cross-sectional area and found no scaling effect present with regards to resistivity. In addition, it was also found to have an electromigration activation energy, the main failing point of interconnects, to be double that of copper and able to withstand current densities of 108 A/cm2, orders of magnitude higher than copper. The results give credence to this class of materials potential for future downscaled devices.

In a joint effort utilizing modified sample preparation, microscopy, X‐ray diffraction and micro‐fabrication, it became possible to prepare single crystals of the “hidden” phase AlCr2. High‐resolution X‐ray diffraction analysis is described in detail for two crystals with the similar overall composition, but different degree of disorder, which seems to be the main cause for the differing unit cell parameters. Chemical bonding analysis of AlCr2 in comparison to prototypical MoSi2 shows pronounced differences reflecting the interchange of main group element vs. transition metal as majority component., Hidden crystals: With a modified synthesis approach and micro‐fabrication technique, it was possible to isolate micrometer‐sized single crystals of AlCr2 from a largely polycrystalline sample. Chemical bond analysis shows close relation to elements, in contrast to a quite localized bonding pattern in the prototype, MoSi2.

Numerous bioactive components exist in human milk including free oligosaccharides, which represent some of the most important, and provide numerous health benefits to the neonate. Considering the demonstrated value of these compounds, much interest lies in characterising structurally similar oligosaccharides in the dairy industry. In this study, the impacts of days post-parturition and parity of the cows on the oligosaccharide and lactose profiles of their milk were evaluated. Colostrum and milk samples were obtained from 18 cows 1&ndash, 5 days after parturition. Three distinct phases were identified using multivariate analysis: colostrum (day 0), transitional milk (days 1&ndash, 2) and mature milk (days 3&ndash, 5). LS-tetrasaccharide c, lacto-N-neotetraose, disialyllacto-N-tetraose, 3&rsquo, sial-N-acetyllactosamine, 3&rsquo, sialyllactose, lacto-N-neohexaose and disialyllactose were found to be highly affiliated with colostrum. Notably, levels of lactose were at their lowest concentration in the colostrum and substantially increased 1-day post-parturition. The cow&rsquo, s parity was also shown to have a significant effect on the oligosaccharide profile, with first lactation cows containing more disialyllacto-N-tetraose, 6&rsquo, sialyllactose and LS-tetrasaccharide compared to cows in their second or third parity. Overall, this study identifies key changes in oligosaccharide and lactose content that clearly distinguish colostrum from transitional and mature milk and may facilitate the collection of specific streams with divergent biological functions.

Efficient delivery of oral drugs is dependent on their solubility in human intestinal fluid, a complex and dynamic fluid that contains colloidal structures composed of small molecules. These structures solubilize poorly water-soluble compounds, increasing their apparent solubility, and possibly their bioavailability. In this study, we conducted coarse-grained molecular dynamics simulations with data from duodenal fluid samples previously acquired from five healthy volunteers. In these simulations, we observed the self-assembly of mixed micelles of bile salts, phospholipids, and free fatty acids. The micelles were ellipsoids with a size range of 4-7 nm. Next, we investigated micelle affinities of three model drugs. The affinities in our simulation showed the same trend as literature values for the solubility enhancement of drugs in human intestinal fluids. This type of simulations is useful for studies of events and interactions taking place in the small intestinal fluid. ispartof: MOLECULAR PHARMACEUTICS vol:17 issue:10 pages:3837-3844 ispartof: location:United States status: published

Hydrogen is a clean energy with high efficiency, while the storage and transport problems still prevent its extensive use. Because of the large specific surface area and unique electronic structure, two-dimensional materials have great potential in hydrogen storage. Particularly, monolayer 2H-WS2 has been proven to be suitable for hydrogen storage. But there are few studies concerning the other two phases of WS2 (1T, 1T′) in hydrogen storage. Here, we carried out first-principle calculations to investigate the hydrogen adsorption behaviors of all the three phases of WS2. Multiple hydrogen adsorption studies also evaluate the hydrogen storage abilities of these materials. Comprehensive analysis results show that the 1T′-WS2 has better hydrogen storage performance than the 2H-WS2, which means phase engineering could be an effective way to improve hydrogen storage performance. This paper provides a reference for the further study of hydrogen storage in two-dimensional materials.

Scanning electron microscopy coupled with microanalysis (SEM-EDX) is an important analytical tool for the morphological and chemical characterization of different types of materials. In many applications, SEM-EDX elemental maps are usually used and processed as images, thus flattening and reducing the spectroscopic information contained in EDX hyperspectral data cubes. The exploitation of the full hyperspectral dataset could be indeed very useful for the study of complex matrices like soil. In order to maximize the information attainable by SEM-EDX data cubes analysis, the software package “Datamuncher Gamma” was implemented and applied to study soil aggregates. By using this approach, different phases (silicates, aluminosilicates, Ca-carbonates, Ca-phosphates, organic matter, iron oxides) inside soil aggregates were successfully identified and segmented. The advantages of this method over the common ROI imaging approach are presented. Finally, this method was used to compare different aggregates in a Cr-polluted soil and understand their possible pedological history. The present method can be used for the analysis of every type of SEM-EDX data cubes, allowing its application to different types of samples and fields of study.

With the purpose of investigating the reactivity of Fe carbide as an active phase in Fischer-Tropsch catalysis, we studied the formation of a well-defined Fe carbide surface structure resulting from carbon exposure of an Fe film on Au(111). Using two different sources of carbon (C), namely atomic carbon and ethylene gas, we used synchrotron X-ray photoelectron spectroscopy (XPS) to show that a 6 ML Fe film readily converts into a well-defined and thermodynamically stable carbide phase. Scanning tunneling microscopy (STM) showed that the surface of the Fe carbide film is crystalline and is dominated by Fe(110)-like facets perturbed into a (2 × 2) periodic structure due to insertion of C in the interstitial sites. The reactivity of the carbide film toward CO, H 2 , and O 2 was furthermore probed by XPS under vacuum conditions. While the pristine Fe carbide surface was unreactive toward hydrogen gas at 500 K, we interestingly found that CO dissociation from a preadsorbed monolayer of CO takes place already at low temperature. This observation points to an intrinsic activity of the Fe carbide phase where additional carbon originating from CO can be placed in the Fe carbide surface. The catalytic significance of the model catalyst surface presented here is that it can be seen as a stable Fe carbide phase with intrinsically vacant sites for additional C insertion at elevated pressure, and we propose that such additional C may act as active species in C-C coupling reactions during FTS. The studies pave the way for a better understanding of FTS processes on Fe-based catalysts on the basis of a well-defined model surface.

The purpose of this study was to evaluate the effect of fat sources and emulsifier supplementation in different phases on growth performance of broilers. Treatments were; (T1) basal ration (BR) which contained soy oil (SO) and had inclusion of emulsifier for whole life, (T2) BR which contained poultry fat (PO) and had inclusion of emulsifier for whole life, (T3) BR which contained oxidized oil (OO) and had inclusion of emulsifier for whole life, (T4) BR which contained SO and had inclusion of emulsifier during starter phase (T5) BR which contained PO and had inclusion of emulsifier during the starter phase, (T6) BR which contained OO and had inclusion of emulsifier during the starter phase, (T7) BR which contained SO and had inclusion of emulsifier during the starter phase (T8) BR which contained PO and had inclusion of emulsifier during the grower phase, (T9) BR which contained OO and had inclusion of emulsifier during the grower phase, (T10) BR which contained SO and had inclusion of emulsifier during the finisher phase, (T11) BR which contained PO and had inclusion of emulsifier during the finisher phase (T12) BR which contained OO and had inclusion of emulsifier during the finisher phase. The Basal ration which contained SO and supplemented emulsifier during the grower phase and throughout life increased the body weight gain. The supplementation of emulsifier in the finisher phase and throughout life in a diet which contained SO had better feed conversion ratio. The supplementation of emulsifier in the finisher phase and throughout life in SO based diet increased the dry matter and crude fat digestibility. We recommend emulsifier supplementation in the finisher phase for the economic point of view.

International audience; According to a recent Hume-Rothery approach, the electron concentration, e/a, and the average radius can be used to identify the domain of stability of HEAs and to estimate the phases that may occur in the alloy. The present study investigates the influence of the electronic polymorphism of nickel on the efficiency of the classification and on the design of HEAs for magnetic applications. Many different compositions were used, based on 4 to 7 elements out of a total 13 different elements (Co, Cr, Fe, Ni, Al, Cu, Pd, Ti, Mn, V, Nb, Sn, Ru). Phases have been determined by X-ray and neutron diffraction as well as in some cases high energy X-ray diffraction. The e/a for the constituent elements is calculated according to Massalski. The two polymorphic electronic structure of nickel, namely (e/a) Ni ¼ 1 or (e/a) Ni ¼ 2 are considered. The average e/a for the alloy is calculated assuming a solid solution case. The electronic structure [Ar] 3d 9 4s 1 seems to be more appropriate for the classification of HEAs. Based on a Self-organising Map predictions are made for the average magnetic moment at saturation for this electronic structure of Ni. Non-saturated values and data from the literature are compared with the predictions. The consequences of such results when modelling the structure and properties of Ni containing HEAs are presented, in particular the consideration of the shape and transformation of the Brillouin zone.

Ytterbium silicate coatings were deposited on SiCf/SiC ceramics matrix composite (CMC) substrates by plasma spray-physical vapor deposition (PS-PVD), and the microstructures and phase constituents of the coatings were studied. The results show that the Yb2SiO5 coating prepared with high power and low pressure (65 kW/2 mbar) had quasi-columnar structure, mainly deposited from the vapor phase, whereas the coating prepared with low power and high pressure (40 kW/10 mbar) had a typical layered structure, mainly deposited from the liquid phase. The deposition efficiency of parameter A (~2 &mu, m/min) was also significantly lower than that of parameter B (~20 &mu, m/min). After annealing at 1300 &deg, C for 20 h, the coating prepared by 65 kW/2 mbar was mainly composed of ytterbium disilicate phase (77.2 wt %). The coating also contained some silicon-rich phase. The coating prepared by 40 kW/10 mbar basically consisted of ytterbium monosilicate (63.6 wt %). In addition, a small amount of silicon-rich phase and ytterbium-rich phase were also present in the coating. Accompanied with calculation results by the FactSage software, the cause of deviations in phase compositions was analyzed.

Intestinal permeability assessment is an important aspect of drug development, which strongly depends on the solvent system used in the intestinal donor compartment. For this purpose, human intestinal fluids (HIF) can be considered as the golden standard. A recent study demonstrated a reduced apparent permeation across rat intestinal tissue from fed versus fasted state HIF for 9 out of 16 compounds tested. Commercially available fed and fasted state simulated fluids (FeSSIF and FaSSIF) reproduced this food effect for only 3 out of 16 compounds. To elucidate this observed difference, the current study assessed the impact of relevant intestinal fluid factors (bile salt, phospholipids, cholesterol, free fatty acids (FFA), monoacylglycerides (MAG)) and 2-factor interactions at a fixed pH of 6.5 on drug permeation across both rat tissue (Ussing chambers setup) and an artificial membrane (dialysis setup). Four representative compounds were selected for the permeation experiments: for propranolol and indomethacin, a food-induced permeation reduction was previously seen in both HIF and SIF; for metoprolol and darunavir, a reduction was only seen in HIF. Using a fractional 25-1 design of experiments (DoE) approach, 16 SIF combinations were defined as donor media for permeation studies. In the Ussing chambers (rat tissue), FFA and MAG reduced the permeation for all 4 compounds. Only for propranolol and indomethacin, permeation was further reduced by bile salts and phospholipids. This explains why the use of FeSSIF vs FaSSIF, lacking FFA and MAG, predicted a negative food effect for propranolol and indomethacin but not for metoprolol and darunavir. In the dialysis set-up using an artificial membrane, significantly higher permeation rates compared to the Ussing chambers were observed. Under those conditions, FFA and MAG no longer reduced permeation, while bile salts and phospholipids still did. This may indicate that lipidic structures can provide depot release in the case of a dynamic equilibrium between free and entrapped drug. ispartof: EUROPEAN JOURNAL OF PHARMACEUTICAL SCIENCES vol:121 pages:338-346 ispartof: location:Netherlands status: published

Tantalum is a very popular material for the industry as a whole because of very important characteristics such as: high melting point, significant thermal and electrical conductivity, high toughness and resistance to corrosion and good biocompatibility. Since the tantalum metal is sensitive to O, N and H gases, tantalum coating layers are deposited only using the vacuum plasma spray process (VPS), which has, in the past few years been used successfully for preparing coatings which are widely used in the preparation of metal implants. The aim of this paper was to, at a low pressure inert gas eliminate the influence of the surrounding atmosphere on the melted Ta powder particles and produce coatings with mechanical and structural characteristics which will find application in biomedicine. For depositing the coating a commercial tantalum powder AMPERIT® 151065 grain size of 10 - 30 μm was used. The powder was deposited with a plasma F4 gun at a distance of substrates at 300 mm. The Ta coating layers were deposited with a thickness of 60 to 70 μm on steel substrates. As the plasma gas used was a mixture of Ar and He inert gases. The microhardness of the coating was tested using the HV0.3 method and the tensile strength of the coatings bond was tested by the tensile method in accordance with the ASTM C633-1 standard. The microstructure of the coating in deposited state and after etching was studied on an optical microscope (OM) and scanning electron microscope (SEM). Etching the coating was carried out in the reagent which consisted of two parts of nitric acid, two parts hydrofluoric acid, and five parts water (2HNO3: 2HF: 5H2O). The structure of the coating consists solely of a tough αTa phase with a body centered cubic lattice. Tests have shown that layers of VPS - Ta coatings have the microstructure and mechanical properties which completely support the use of the coating in the process of making implants. Tantal je veoma atraktivan materijal za industriju u celini zbog veoma bitnih osobina kao što su: visoka temperatura topljenja, značajna toplotna i električna provodljivost, visoka žilavost i otpornost na koroziju i dobra biokompatibilnost. Pošto je tantal metal osetljiv na gasove O, N i H, slojevi prevlake tantala se isključivo deponuju vakuum plazma sprej procesom (VPS), koji se u poslednjih nekoliko godina uspešno koristi za izradu prevlaka koje imaju široku primenu u izradi metalnih implanata. Cilj rada bio je da se na niskom pritisku inertnog gasa eliminiše uticaj okolne atmosfere na istopljene čestice praha Ta i proizvedu prevlake mehaničkih i strukturnih karakteristika koje će naći primenu u biomedicini. Za deponovanje prevlake koristio se komercijalni prah tantala AMPERIT® 151.065 granulacije od 10 - 30µm. Prah je deponovan sa plazma pištoljem F4 na odstojanju podloge od 300 mm. Slojevi Ta prevlaka su deponovani sa debljinom od 60 do 70µm na čeličnim podlogama. Kao plazma gas koristila se mešavina inertnih gasova Ar i He. Mikrotvrdoća prevlake ispitana je metodom HV0.3 a zatezna čvrstoća spoja prevlake ispitana je metodom na zatezanje u skladu sa standardom ASTM C633-1. Mikrostruktura prevlake u deponovnom stanju i u stanju posle nagrizanja ispitana je na optičkom mikroskopu (OM) i na skening elektronskom mikroskopu (SEM). Nagrizanje prevlake sprovedeno je u reagensu koji se sastojao od dva dela azotne kiseline, dva dela fluorovodonične kiseline i pet delova vode (2HNO3 : 2HF : 5H2O). Struktura prevlake se isključivo sastoji od žilave α-Ta faze sa zapreminski centriranom kubnom rešetkom. Ispitivanja su pokazala da slojevi VPS - Ta prevlake imaju mikrostrukturu i mehaničke karakteristike koje u potpunosti omogućavaju primenu prevlake u procesu izrade implanata.

Global warming may modify the timing of dormancy release and spring growth of buds of temperate fruit crops. Environmental regulation of the activity-dormancy cycle in perennial plants remains poorly understood at the metabolic level. Especially, the fine-scale metabolic dynamics in the meristematic zone within buds has received little attention. In this work we performed metabolic profiling of intact floral primordia of Ribes nigrum isolated from buds differing in dormancy status using high-resolution magic angle spinning (HR-MAS) NMR. The technique proved useful in monitoring different groups of metabolites, e.g., carbohydrates and amino acids, in floral primordia and allowed metabolic separation of primordia from endo- and ecodormant buds. In addition, due to its nondestructive character, HR-MAS NMR may provide novel insights into cellular compartmentation of individual biomolecules that cannot be obtained using liquid-state NMR. Out results show that HR-MAS NMR may be an important method for metabolomics of intact plant structures.

The use of secondary aluminum alloys is increasing because it contributes to the decrease of production costs. However, these alloys contain bigger amount of iron. Iron has a negative effect and therefore its elimination is necessary in order to add some elements, which are also called correctors of iron. The most frequently used corrector is manganese. Another quite often used correctors are chromium, potassium, magnesium, vanadium. In the following work, vanadium is used as a corrector of iron phases. The application of vanadium in aluminum alloys has a positive impact on their mechanical properties, increases the tensile strength, ductility and hardness. As experimental material AlSi6Cu4 alloy was used. It was alloyed by master alloy AlFe10. After adding to the master alloy the iron content, the critical value in the alloy exceeded. Vanadium was added to AlSi6Cu4 alloy in different quantities. The image analysis (software NIS-Elements) was used for quantifying the amount of iron based intermetallic phases and determination of average values.

The synthesis and self-assembly behavior of newly designed BINOL-based amphiphiles is presented. With minor structural modifications, the aggregation of these amphiphiles could be successfully tuned to form different types of assemblies in water, ranging from vesicles to cubic structures. Simple sonication induced rearrangement of different kinetically stable aggregates into thermodynamically stable self-assembled nanotubes as observed by Cryo-TEM.

Selection of wasteform materials for higher activity nuclear waste containment is considered. Utilization of materials such as glasses, ceramics, glass composite materials and cements is discussed as practiced in different countries. Emphasis is on multiple parameter approach on selecting the wasteform where the durability is not solely the most important characteristic.

BACKGROUND AND PURPOSE: In vivo detection of β-amyloid (Aβ) plaques in Alzheimer's disease (AD) is now possible with 11C-PiB positron emission tomography (PET). Conventionally, a cortical:cerebellar PiB uptake ratio threshold of 1.4-1.5 has been used to categorize at-risk subjects as “amyloid-positive” and “amyloid-negative.” It has been suggested that this threshold is too conservative and may miss early amyloid pathology. We investigated the relationship between conventional and lower baseline 11C-PiB PET thresholds for raised amyloid load and the subsequent clinical and radiological progression of mild cognitive impairment (MCI) cases longitudinally. METHODS: We serially determined the cortical amyloid load with 11C-PiB PET of 44 MCI subjects over 2 years and compared findings with those for 12 healthy controls (HC) and 5 AD cases. RESULTS: Twenty-four subjects were classified as normal at baseline with mean cortical PiB standard uptake value ratios (SUVR) between 1.2 and 1.5. Their cognitive status remained stable over time. Three of these cases increased their amyloid load above a threshold of 1.5 over 2 years. Twenty-seven “raised amyloid” MCI cases with baseline cortical SUVRs above 1.5, showed deteriorating cognition. Note that 50% of these cases converted clinically to AD during the follow-up period. CONCLUSION: Use of a PiB SUVR threshold of >1.5 for raised amyloid missed 14.3% of MCI cases who likely had Thal stage 1 or 2 pathology and showed a progressive amyloid increase over 2 years. Lowering the threshold for abnormality to 1.3 abolished all false negatives but resulted in 75% of HCs being falsely diagnosed as raised amyloid subjects.

The circadian clock is an endogenous oscillator that controls daily rhythms in metabolism, physiology, and behavior. Although the timekeeping components differ among species, a common design principle is a transcription-translation negative feedback loop. However, it is becoming clear that other mechanisms can contribute to the generation of 24 h rhythms. Peroxiredoxins (Prxs) exhibit 24 h rhythms in their redox state in all kingdoms of life. In mammalian adrenal gland, heart and brown adipose tissue, such rhythms are generated as a result of an inactivating hyperoxidation reaction that is reduced by coordinated import of sulfiredoxin (Srx) into the mitochondria. However, a quantitative description of the Prx/Srx oscillating system is still missing. We investigate the basic principles that generate mitochondrial Prx/Srx rhythms using computational modeling. We observe that the previously described delay in mitochondrial Srx import, in combination with an appropriate separation of fast and slow reactions, is sufficient to generate robust self-sustained relaxation-like oscillations. We find that our conceptual model can be regarded as a series of three consecutive phases and two temporal switches, highlighting the importance of delayed negative feedback and switches in the generation of oscillations. Deutsche Forschungsgemeinschaft

Liquid crystalline phases (LCs) readily exhibit optical responsivity to small fluctuations in their immediate environment. By encapsulating LC phase forming compounds within polymer fibers through the electrospinning process (a fiber spinning method known for being a fast way of forming chemically diverse non-woven mats), it is possible to create functionalized LC-polymer fiber mats that are responsive as well. As these fiber mats can be handled macroscopically, a usercan observe the responses of the mats macroscopically without the need for bulky electronics. This thesis presents several non-woven fiber mats that were coaxially electrospun to contain LC within their individual polymer fibers cores for use as novel volatile organic compound (VOC) sensors. The mats are flexible, lightweight, and shown to both macroscopically and microscopically respond to toluene gas. Such gas responsive mats may be incorporated into garments for visually alerting the wearer when they are exposed to harmful levels of VOCs for example. Additionally, the interaction and re-prioritization of several electrospinning variables (from the chemistry based to the processing based) for forming the LC-mats are also discussed. The balance of these variables determines whether a wide range of phenomena occur during fiber formation. For instance, unexpected phase separation between the polymer sheath solution and the LC core can mean the difference between forming fully dried fibrous mats and wet/meshed films. A chapter is devoted to discussing the impact that solvent miscibility with an LC can have on fiber production, including also the effect that water can have when condensed into the electrospinning coaxial jet. The fiber shapes that the polymer fiber sheaths adopt (beaded versus non-beaded), as well as the continuity of the LC core, will influence the visual app earance of the mats. These optical properties, in turn, influence the mats’ responsivity to gases and whether the responses can be macroscopically observed with or without additional polarizers. During two types of gas sensing experiments --mats exposed to gas when contained in a cell, and mats exposed to gas diffused in ambient air without containment, we see that not all fibers within a mat respond at the same time. Moreover, different segments of the fibers within the same non-woven mat also show slightly different rates of response due to variations in fiber thickness, LC content, and whether the fiber cores had variations in LC filling (i.e. LC director twists, and gaps).

The retardant effects of citric acid on the properties of ettringite binders are not yet fully understood. This investigation provides insights into the effects of citric acid on both the fresh and hardened state properties of the binder produced from the hydration between ladle slag and gypsum (LSG). The results revealed that LSG's initial setting time could be controlled via different citric acid contents and could range from 20 min to 2 h. Citric acid is effective at relatively high dosages; in its absence, ettringite formed almost immediately directly following exposure to water. The presence of citric acid alters the hydration reactions in LSG. AFm was found to be one of main hydration products; citric acid promoted the conversion from ettringite to monosulfate, detected by using solid-state 27Al magic-angle spinning nuclear magnetic resonance spectroscopy. In addition, citric acid increased the compressive strength of LSG mortars by up to 45%. This work was done as part of the FLOW project (project number 8904/31/2017) funded by Business Finland in the ERA-MIN 2 Innovation program (EU Horizon 2020 program) and industrial partners including SSAB Europe Oy, Saint-Gobain Finland Oy, Kiertokaari Oy, and Destaclean Oy. The authors appreciate support from Prof. Yiannis Pontikes (KU Leuven, Belgium) for in situ XRD measurements and Samppa Hyvarinen for lab work. Hoang Nguyen gratefully acknowledges financial support from the Tauno Tonning Research Foundation. A.M.K. and V.-V.T. acknowledge financial support from the Kvantum Institute (University of Oulu) and the Academy of Finland (grant numbers 289649 and 294027).

This contribution concentrates on the possibilities of additive manufacturing of high-entropy clad layers by laser processing. In particular, the effects of the laser surface processing parameters on the microstructure and hardness of high-entropy alloys (HEAs) were examined. AlCoCrFeNi alloys with different amounts of aluminum prepared by arc melting were investigated and compared with the laser beam remelted HEAs with the same composition. Attempts to form HEAs coatings with a direct laser deposition from the mixture of elemental powders were made for AlCoCrFeNi and AlCrFeNiTa composition. A strong influence of solidification rate on the amounts of face-centered cubic and body-centered cubic phase, their chemical composition, and spatial distribution was detected for two-phase AlCoCrFeNi HEAs. It is concluded that a high-power laser is a versatile tool to synthesize interesting HEAs with additive manufacturing processing. Critical issues are related to the rate of (re)solidification, the dilution with the substrate, powder efficiency during cladding, and differences in melting points of clad powders making additive manufacturing processing from a simple mixture of elemental powders a challenging approach.

In this study, the impact of impurities incorporated into plated nickel seed layer on silicide formation and the influence of annealing temperature on the fill-factor (FF) loss of solar cells with Ni-Cu contacts is investigated. The silicide growth of electro-less plated nickel seed layer is significantly retarded compared with literature data on physical-vapor-deposition (PVD)-based nickel annealed at 550 degrees C. X-ray photoelectron spectroscopy and X-ray diffraction reveal the presence of SiO2 at the Ni-Si interface and the formation of nickel phosphides in addition to nickel silicide. The retardation in silicide growth is attributed to the presence of (111) planes after the texturing process and contaminants in the seed layer. Varying the annealing temperature of fabricated cells from 350 degrees C to 425 degrees C led to a decrease in the average FF from 79.3% to 77.5%. The loss analysis is based on Suns-V-oc measurements, illuminated current-voltage parameters, and dark current-voltage curve fitting based on a three-diode model. It reveals that the FF loss is dominated by increased junction recombination, whereas losses due to third-diode component become significant for annealing at 400 degrees C and higher temperatures. The results highlight the need to carefully tune the seed layer annealing parameters to the interface conditions and junction depth of solar cells.

Measuring martian organics and methane The Curiosity rover has been sampling on Mars for the past 5 years (see the Perspective by ten Kate). Eigenbrode et al. used two instruments in the SAM (Sample Analysis at Mars) suite to catch traces of complex organics preserved in 3-billion-year-old sediments. Heating the sediments released an array of organics and volatiles reminiscent of organic-rich sedimentary rock found on Earth. Most methane on Earth is produced by biological sources, but numerous abiotic processes have been proposed to explain martian methane. Webster et al. report atmospheric measurements of methane covering 3 martian years and found that the background level varies with the local seasons. The seasonal variation provides an important clue for determining the origin of martian methane. Science , this issue p. 1096 , p. 1093 ; see also p. 1068

Metallic oxynitrides are materials of interest, since they represent the combination between the properties of the respective nitrides and oxides. The thermal stability of the oxynitride films is important for different applications, but it has to be differentiated from oxidation resistance. For this evaluation, x-ray diffraction (XRD) patterns have been acquired in situ during heating under two different atmospheres selected to avoid external oxidation (vacuum and a He/H2 mixture). Such tests were performed on selected Zr-O-N films presenting different chemical compositions and phases (metal-rich N-deficient nitride, (oxy)nitride, and O-rich disordered oxynitride). The influence of the addition of Ti has been studied in films including also TiN-like phases. To facilitate the phase identification, the intensity of the different peaks in the XRD patterns was tuned to highlight the weaker ones. In addition, the intensity of representative peaks of the main phases has been monitored to represent the overall behavior under heating. It has been found that the structure of the films evolves to the formation of ZrO2, the phase with tetragonal symmetry at lower temperature and the monoclinic one at higher temperature. Films including Ti showed an improved thermal stability, without the formation of the monoclinic oxide even at 1000 ºC., The financial support of Portuguese Foundation of Science and Technology (FCT), under the project number IF/00671/2013 is gratefully acknowledged.

Uranium encapsulated in grout was exposed to water vapour for extended periods of time. Through synchrotron x-ray powder diffraction and tomography measurements, uranium dioxide was determined the dominant corrosion product over a 50-week time period. The oxide growth rate initiated rapidly, with rates comparable to the U + H2O reaction. Over time, the reaction rate decreased and eventually plateaued to a rate similar to the U + H2O + O2 reaction. This behaviour was not attributed to oxygen ingress, but instead the decreasing permeability of the grout, limiting oxidising species access to the metal surface.

Zr-Nb alloys are known to perform better in corrosion and hydrogen pick-up than other Zr alloys but the mechanism by which this happens is not well understood. Atomistic simulations using density functional theory of both tetragonal and monoclinic ZrO2 were performed, with intrinsic defects and Nb dopants. The overall defect populations with respect to oxygen partial pressure were calculated and presented in the form of Brouwer diagrams. Nb is found to favour 5 + in monoclinic ZrO2 at all partial pressures, but can exist in oxidation states ranging from 5 + to 3 + in the tetragonal phase. Nb5+ is charge balanced by Zr vacancies in both phases, suggesting that contrary to previous assumptions, Nb does not act as an n-type dopant in the oxide layer. Clusters containing oxygen vacancies were considered, Nb2+ was shown to exist in the tetragonal phase with a binding energy of 2.4 eV. This supports the proposed mechanism whereby low oxidation state Nb ions (2 + or 3+) charge balance the build-up of positive space-charge in the oxide layer, increasing oxygen vacancy and electron mobility, leading to near-parabolic corrosion kinetics and a reduced hydrogen pick-up. Previous experimental work has shown that tetragonal ZrO2 transforms to the monoclinic phase during transition, and that during transition a sharp drop in the instantaneous hydrogen pick-up fraction occurs. The oxidation of lower charge state Nb defects to Nb5+ during this phase change, and the consequent temporary n-doping of the oxide layer, is proposed as an explanation for the drop in hydrogen pick-up during transition.

Understanding the surface chemistry and oxygen surface exchange activity in mixed conducting perovskite and related perovskite oxides is of great relevance in developing electrochemical devices. Mixed conducting Ruddlesden–Popper Lan+1NinO3n+1 phases (n = 1, 2 and 3) have been considered as promising electrodes for electrochemical energy conversion cells due to their layered structure allowing non-stoichiometric defect structures. This study focuses on a systematic investigation of the chemical composition of the outermost atomic surfaces of as-deposited and annealed epitaxial films of Lan+1NinO3n+1 (n = 1, 2 and 3). For both as-deposited and annealed films, the analysis of the outermost surface using low energy ion scattering shows preferential LaO-termination. The results also provide evidence of an associated Ni-enrichment below the outermost surface. These findings suggest significant atomic rearrangement occurs during deposition and subsequent annealing. To investigate the thermal stability of these films during deposition, further microstructural analysis was carried out by means of high-resolution scanning transmission electron microscopy, showing significant re-orientation of LaO layers after a post-annealing heat treatment. In thin films of n = 2, 3 phases, surface restructuring reduces the epitaxy of the films and hence any potential beneficial anisotropy in transport properties will be lost. Care must therefore be exercised in processing these materials for electrode applications.

Giant unilamellar vesicles (GUVs) are well-established model systems for studying membrane structure and dynamics. Electroformation, also referred to as electro-swelling, is one of the most prevalent methods for producing GUVs, as it enables modulation of the lipid hydration process to form relatively mono-disperse, defect-free vesicles. Currently, however, it is relatively expensive and time-consuming compared to other methods. In this study, we demonstrate that 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) GUVs can be prepared readily at a fraction of the cost on stainless steel electrodes such as commercially available syringe needles, without any evidence of lipid oxidation or hydrolysis.

Colloidal suspensions are an experimental model system for studying structural and mechanical properties of soft materials. These properties are manifested differently in colloidal solid-like phases such as crystals, glasses and gels. To further understand relations between structural and mechanical properties, it is necessary to develop well-defined colloids and employ techniques such as microscopy and rheology to study the structure and mechanics of their suspensions. This thesis presents five experimental chapters dealing with the synthesis and characterization of colloids and their suspensions. The first part of the thesis describes facile synthesis methods for latex, conjugated polymer and microgel colloids. In the second part, measurements of crystal-to-glass and glass-to-gel phase transformations in dense suspensions of microgel particles are presented.

Recent experiments [A. M. Schaeffer et al., Proc. Natl. Acad. Sci. USA 112, 60 (2015)] have shown that lithium presents an extremely anomalous isotope effect in the 15–25 GPa pressure range. In this article we have calculated the anharmonic phonon dispersion of 7Li and 6Li under pressure, their superconducting transition temperatures, and the associated isotope effect. We have found a huge anharmonic renormalization of a transverse acoustic soft mode along ΓK in the fcc phase, the expected structure at the pressure range of interest. In fact, the anharmonic correction dynamically stabilizes the fcc phase above 25 GPa. However, we have not found any anomalous scaling of the superconducting temperature with the isotopic mass. Additionally, we have also analyzed whether the two lithium isotopes adopting different structures could explain the observed anomalous behavior. According to our enthalpy calculations including zero-point motion and anharmonicity it would not be possible in a stable regime., The authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (Grant No. FIS2016-76617-P) and the Department of Education, Universities and Research of the Basque Government and the University of the Basque Country (Grant No. IT756-13). M.B. is also thankful to the Department of Education, Language Policy and Culture of the Basque Government for a predoctoral fellowship (Grant No. PRE-2015-2-0269).

The combustion of poultry litter, which is rich in phosphorus, in a fluidized bed combustor (FBC) is associated with agglomeration problems, which can lead to bed defluidization and consequent shutdown of the installation. Whereas earlier research indicated coating induced agglomeration as the dominant mechanism for bed material agglomeration, it is shown experimentally in this paper that both coating and melt induced agglomeration occur. Coating induced agglomeration mainly takes place at the walls of the FBC, in the freeboard above the fluidized bed, where at the prevailing temperature the bed particles are partially molten and hence agglomerate. In the ash, P2O5 forms together with CaO thermodynamically stable Ca3(PO4)2, thus reducing the amount of calcium silicates in the ash. This results in K/Ca silicate mixtures with lower melting points. On the other hand, in-bed agglomeration is caused by thermodynamically unstable, low melting HPO42- and H2PO4- salts present in the fuel. In the hot FBC these salts may melt, may cause bed particles to stick together and may subsequently react with Ca salts from the bed ash, forming a solid bridge of the stable Ca3(PO4)2 between multiple particles. © 2014 Elsevier Ltd. publisher: Elsevier articletitle: Coating and melt induced agglomeration in a poultry litter fired fluidized bed combustor journaltitle: Biomass and Bioenergy articlelink: http://dx.doi.org/10.1016/j.biombioe.2014.07.013 content_type: article copyright: Copyright © 2014 Elsevier Ltd. All rights reserved. ispartof: Biomass & Bioenergy vol:69 pages:71-79 status: published

We report the preparation and characterization of monoolein cubosomes that can be easily surface modified through adsorption of a single layer of cationic poly-epsilon-lysine. Poly-epsilon-lysine coated cubosomes show remarkable stability in serum solution, are nontoxic and, are readily internalized by HeLa cells. The poly-epsilon-lysine coating provides chemical handles for further bioconjugation of the cubosome surface. We also demonstrate that the initial release rate of a hydrophilic drug, Naproxen sodium, from the cubosomes is retarded with just a single layer of polymer. Interestingly, cubosomes loaded with Naproxen sodium, recently shown to have anticancer properties, cause more apoptosis in HeLa cells when compared to free unencapsulated drug.

By means of CALPHAD approach, thermodynamic assessments of the Mg-Pb and Mg-Bi systems were carried out based on the available experimental data including thermodynamic properties and phase equilibrium data. The liquid phase was described with both the substitutional solution model and the associate model, and two sets of self-consistent thermodynamic parameters for the Mg-Pb and Mg-Bi systems were obtained, respectively. It was found that the associate model can account for the experimental data more satisfactorily than the substitutional solution one, especially for the liquid phase with the short-range order behavior.

An array of quartz crystals coated with different room-temperature ionic liquids (RTILs) is proposed for the analysis of flavors by quartz crystal microbalance (QCM) measurements. Seven RTILs were adopted as sensing layers, all containing imidazolium or phosphonium cations, differing from one another in the length and branching of alkyl groups and neutralized by different anions. The array was at first applied to the analysis of 31 volatile organic compounds (VOCs), such as alcohols, phenols, aldehydes, esters, ketones, acids, amines, hydrocarbons and terpenes, chosen as representative components of a wide variety of food flavors. Multivariate data analysis by the principal component analysis (PCA) approach of the set of the corresponding responses led to separated clusters for these different chemical categories. To further prove the good performance of the RTIL-coated quartz crystal array as an "electronic nose", it was applied to the analysis of headspaces from cinnamon samples belonging to different botanical varieties ( Cinnamon zeylanicum and Cinnamon cassia ). PCA applied to responses recorded on different stocks of samples of both varieties showed that they could be fully discriminated.

In this paper, the results of the investigation of the morphology and phase composition of the oxide layers formed on the surface of the 1H18N9T acid proof steel foil by confocal Raman micro-spectroscopy with optical microscopy, SEM, XRD and TEM-EDS-SADP are presented. The foil oxidation was performed by thermo-programmed heating up to 823, 1023 or 1113 K and next annealing at the final temperatures in the air flow for 48 h, 4 h and 4 h, respectively. The great advantages of the use of the Raman spectroscopy for the phase determining in the oxide layers on the acid proof steel foil are shown. Moreover the possibility of applying the optical microscopy for investigation of the surface morphology of both the initial steel foil and the oxide layers is pointed out.

We report on the effect of fullerenes (C-60) on the stability of nanostructured lipid emulsions. These (oil-in-water) emulsions are essentially aqueous dispersions of lipid particles exhibiting self-assembled nanostructures at their cores. The majority of previous studies on fullerenes were focused on planar and spherical lipid bilayer systems including pure lipids and liposomes. In this work, fullerenes were interacted with a lipid that forms nanostructured dispersions of non-lamellar self-assemblies. A range of parameters including the composition of emulsions and sonication parameters were examined to determine the influence of fullerenes on in-situ and pre-stabilized lipid emulsions. We found that fullerenes mutually stabilize very low concentrations of lipid molecules, while other concentration emulsions struggle to stay stable or even to form at first instance; we provide hypotheses to support these observations. Interestingly though, we were able to encapsulate varying amounts of fullerenes in sterically stabilized emulsions. This step has a significant positive impact, as we could effectively control an inherent aggregation tendency of fullerenes in aqueous environments. These novel hybrid nanomaterials may open a range of avenues for biotechnological and biomedical applications exploiting properties of both lipid and fullerene nanostructures. (C) 2016 Elsevier Inc. All rights reserved.

Upon addition of a chiral dopant to a nematic liquid crystal, amplification of molecular chirality can occur and consequently a cholesteric liquid crystal is formed. A major challenge in materials science consists in designing efficient chiral dopants that allow for control over chiral amplification by use of an external trigger, for example by irradiation with light, and thereby achieving the control of the dynamic and responsive structure of cholesteric liquid crystals. Here, a chiral photochromic switch bearing two chiral imine units connected viaphenyl spacers was synthesized and characterized in solution, where it can be photo-chemically converted from a colourless ring-opened form 1o to a coloured ring-closed form 1c, reversibly. We show that a small amount of 1o used as a dopant induces the formation of a stable cholesteric liquid crystal. The retention of the photochromic properties of 1, when used as a chiral dopant, allows for reversible photocontrol over the period of the cholesteric helix, and shows the highest values of helical twisting power achieved so far with diarylethene-based photoswitchable dopants.

Surface functionalisation with viscosity sensitive dyes termed 'molecular rotors' can potentially open up new opportunities in sensing, for example for non-invasive biological viscosity imaging, in studying the effect of shear stress on lipid membranes and in cells, and in imaging contacts between surfaces upon applied pressure. We have functionalised microscope slides with BODIPY-based molecular rotor capable of viscosity sensing via its fluorescence lifetime. We have optimised functionalisation conditions and prepared the slides with the BODIPY rotor attached directly to the surface of glass slides and through polymer linkers of 5 kDa and 40 kDa in mass. The slides were characterised for their sensitivity to viscosity, and used to measure viscosity of supported lipid bilayers during photooxidation, and of giant unilamellar vesicles lying on the surface of the slide. We conclude that our functionalised slides show promise for a variety of viscosity sensing applications.

A novel lithium zinc niobium oxide LiZnNb(4)O(11.5) (LZNO) has been found in the Nb-rich part of Li(2)O-ZnO-Nb(2)O(5) system. LZNO, with an original alpha-PbO(2) related structure, has been synthesized by the routine ceramic technique and characterized by X-ray diffraction and transmission electron microscopy (TEM). Reflections belonging to the LZNO phase, observed in X-ray powder diffraction (XRPD) and electron diffraction, have been indexed as monoclinic with unit cell parameters a=17.8358(9)angstrom, b=15.2924(7)angstrom, c=5.0363(3)angstrom and gamma=96.607(5)degrees or as alpha-PbO(2)-like with lattice constants a=4.72420(3)angstrom, b=5.72780(3)angstrom, c=5.03320(3)angstrom, gamma=90.048(16)degrees and modulation vector q=0.3a*+1.1b* indicating a commensurately modulated alpha-PbO(2) related structure. The monoclinic cell is a supercell related to the latter. Using synchrotron powder diffraction data, the structure has been solved and refined as a commensurate modulation (superspace group P112(1)/n(alpha beta 0)00) as well as a supercell (space group P2(1)/b). The superspace description allows us to consider the LZNO structure as a member of the proposed alpha-PbO(2)-Z (3 + 1)D structure type, which unifies both incommensurately and commensurately modulated structures. HRTEM reveals several types of defects in LZNO and structural models for these defects are proposed. Two new phases in Li(2)O-ZnO-Nb(2)O(5) system are predicted on the basis of this detailed HRTEM analysis. (C) 2009 Elsevier Inc. All rights reserved.

The role of superheated water on hydrogen bonding in amide crystallization was examined by the use of low molecular weight N,N'-1,2-ethanediyl-bis(6- hydroxy-hexanamide) model crystals that form hydrogen bonded sheets stacked by van der Waals forces. Thermodynamic, structural and conformational studies reveal that despite a low temperature transition, which originates in a reversible change from cooperative configurational flip-flop to conformational hydroxylic hydrogen bonding, a delicate balance between conformational disorder/order in the aliphatic segments and hydrogen bonding efficiency between the hydrogen bonded moieties validates the role of N,N'-1,2-ethanediyl- bis(6-hydroxy-hexanamide) as a model compound representing the crystalline domains in polyamides. Crystallization from the superheated state of water results in the formation of a thermodynamically metastable phase, where water molecules in the vicinity of the amide moieties shield the interchain hydrogen bonding. Because of this shielding water molecules erase the conformational limitations of the planar amide motifs during crystallization, and trans methylene conformations along the entire molecules coexist with strong intermolecular hydroxylic hydrogen bonding. By annealing or sequential temperature cycles the metastable crystals tend to transform irreversibly into thermodynamically more stable crystals. During the transformation the water molecules migrate from the amide moieties. Since the highly efficient hydrogen bonding between highly ordered hydroxylic end groups decreases the effect of thermally triggered rotating gauche conformers, less effect of the crankshaft type of motion in the methylene segments requires more energy to pursue a solid state crystalline transition. Conclusively, physically bound water molecules near the amide motifs shield intermolecular hydrogen bonding and mediate the formation of stabilizing hydroxylic hydrogen bonds. © 2008 American Chemical Society.

All aluminium products come from melting processes. At the melting temperature, aluminium and its alloys are highly reactive with the metals and the refractories which line the furnace inside. Investigation of interactions of aluminium and its alloys with the refractory materials upon heating is therefore an issue. In this paper this investigation is focused on the model system made of aluminium-silicon mixture at eutectic composition and corundum. In particular, the structural and microstructural features are investigated by high-temperature resolved X-ray diffraction (HTXRD) and bidimensional micro X-Ray diffraction (XRD2). During cooling we followed the crystallization of aluminium and silicon and few single crystallites of a new phase, possibly related to A(19)Fe(5)Si(2), were detected by microXRD(2).

Sodium soap fibers with varying alkyl chain lengths were studied by cryotransmission electron microscopy and differential scanning calorimetery in water and water-propylene glycol mixtures. The morphology of the lamellar fibers was found to be dependent on the chain length of the alkyl chain and the solvent polarity. Cryoelectron microscopy revealed that short-chain (C-10-C-14) sodium soaps have the bilayer plane perpendicular to the fiber width, which enables one to see the bilayer striations on the fibers, whereas long-chain (C-16-C-20) sodium soaps have bilayer planes parallel to the fiber width, and the bilayer striations are not visible. This change in morphology is accompanied by a change in dissolution enthalpy.

The main product of Portland cement hydration is C-S-H. Despite constituting more than half of the volume of hydrated pastes and having an important role in strength development, very little is known about the factors that determine its morphology. To investigate the relationship between the chemical composition, silicate anion structure and morphology of C-S-H, samples were synthesised via silica-lime reactions and by the hydration of C3S under controlled lime concentrations and with/without accelerators. The silicate anion structure of the samples was studied by 29Si magic angle spinning nuclear magnetic resonance spectroscopy and the morphology and chemical composition by TEM and SEM. All samples prepared via silica-lime reactions with bulk Ca/Si up to 1.5 were foil-like. The hydration of C3S at fixed lime concentration yielded foil-like C-S-H for [CaO] 22 mmol L−1. A relationship between the silicate anion structure and the morphology of C-S-H was found for the...

In situ X-ray diffraction studies of structural evolution of colloidal crystal films formed by polystyrene spherical particles upon incremental heating are reported. The Bragg peak parameters, such as peak position, integrated intensity, and radial and azimuthal widths were analyzed as a function of temperature. A quantitative study of colloidal crystal lattice distortions and mosaic spread as a function of temperature was carried out using Williamson-Hall plots based on mosaic block model. The temperature dependence of the diameter of polystyrene particles was obtained from the analysis of Bragg peaks, and the form factor contribution extracted from the diffraction patterns. Four stages of structural evolution in a colloidal crystal upon heating were identified. Based on this analysis, a model of the heating and melting process in the colloidal crystal film is suggested.

Controlling ferroelectric switching in Mg doped lithium niobate (Mg:LN) is of fundamental importance for optical device and domain wall electronics applications that require precise domain patterns. Stable ferroelectric switching has been previously observed in undoped LN layers above proton exchanged (PE) phases that exhibit reduced polarization, whereas PE layers have been found to inhibit lateral domain growth. Here, Mg doping, which is known to significantly alter ferroelectric switchingproperties including coercive field and switching currents, is shown to inhibit domain nucleation and stability in Mg:LN above buried PE phases that allow for precise ferroelectric patterning via domain growth control. Furthermore, piezoresponse force microscopy(PFM) and switching spectroscopy PFM reveal that the voltage at which polarization switches from the 'up' to the 'down' state increases with increasing thickness in pure Mg:LN, whereas the voltage required for stable back switching to the original 'up' state does not exhibit this thickness dependence. This behavior is consistent with the presence of an internal frozen defect field. The inhibition of domain nucleation above PE interfaces, observed in this study, is a phenomenon that occurs in Mg:LN but not in undoped samples and is mainly ascribed to a remaining frozen polarization in the PE phase that opposes polarization reversal. This reduced frozen depolarization field in the PE phase also influences the depolarization field of the Mg:LN layer above due to the presence of uncompensated polarization charge at the PE-Mg:LN boundary. These alterations in internal electric fields within the sample cause long-range lattice distortions in Mg:LN via electromechanical coupling, which were corroborated with complimentary Raman measurements. European Commission - Seventh Framework Programme (FP7) Science Foundation Ireland Swedish Research Council

In situ time-resolved energy dispersive X-ray diffraction (EDXD) was applied to investigate the hydration kinetics of oriented dioleoylphosphocoline (DOPC) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) membranes. The long-range order in the investigated lipid multilayers has been found to vary as a function of hydration in a nonmonotic way. In the first stage, water adsorption increased the long-range order along the normal to the lipid bilayer whereas, in the second one, a progressive loss of interbilayer coherence was observed. Possible molecular mechanisms underlying the experimental observations are discussed.