Hydrate Film Research Articles

Ionomers From Kraft Lignin for Renewable Energy Applications.

Converting industrial/agricultural lignin-rich wastes to efficient, cost-effective materials for electrochemical devices (e.g., fuel cells) can aid in both bio- and energy economy. A major limitation of fuel cells is the weak ion conductivity within the ~2–30-nm thick, ion-conducting polymer (ionomer)-based catalyst-binder layer over electrodes. Here, we strategically sulfonated kraft lignin (a by-product of pulp and paper industries) to design ionomers with varied ion exchange capacities (IECs) (LS x; x = IEC) that can potentially overcome this interfacial ion conduction limitation. We measured the ion conductivity, water uptake, ionic domain characteristics, density, and predicted the water mobility/stiffness of Nafion, LS 1.6, and LS 3.1 in submicron-thick hydrated films. LS 1.6 showed ion conductivity an order of magnitude higher than Nafion and LS 3.1 in films with similar thickness. The ion conductivity of these films was not correlated to their water uptake and IECs. Within the three-dimensional, less dense, branched architecture of LS 1.6 macromolecules, the –SO3H and –OH groups are in close proximity, which likely facilitated the formation of larger ionic domains having highly mobile water molecules. As compared to LS 1.6, LS 3.1 showed a higher glass transition temperature and film stiffness at dry state, which sustained during humidification. On the contrary, Nafion stiffened significantly upon humidification. The smaller ionic cluster within stiff LS 3.1 and Nafion films thus led to ion conductivity lower than LS 1.6. Since LS x ionomers (unlike commercial lignosulfonate) are not water soluble, they are suitable for low-temperature, water-mediated ion conduction in submicron-thick films.

Replacement in CH4-CO2 hydrate below freezing point based on abnormal self-preservation differences of CH4 hydrate

CH4-CO2 replacement for natural gas hydrate exploitation is a win-win method to simultaneously realize CH4 recovery and CO2 sequestration. However, the exchange progress is severely blocked by the reformation of compact CO2 hydrate film. Constructing porous CO2 hydrate could be a promising approach to solve this annoyance. In consideration of the difference in ice layer defects and decomposition rate of CH4 hydrates at different temperatures in its anomalous self-preservation region, in this study, we proposed a concept of CH4-CO2 hydrate replacement by utilizing the multi-defective ice generated from dissociated CH4 hydrate to form porous CO2 hydrate. The CH4-CO2 hydrate exchange experiments occurred at 268.15 K and 272.15 K with rapid CH4 exhaust-CO2 injection were conducted. The results showed that the replacement efficiency at 272.15 K was much higher than at 268.15 K. In addition, we examined the replacement at 274.15 K and replacement with slow gas sweep at 268.15 K for comparison. These experimental results confirmed the possibility of the replacement concept.

Phase behavior of high-pressure CH4-CO2 hydrates in NaCl solutions

Understanding the phase behavior of CH4-CO2 hydrates formed in NaCl solutions is important for gas recovery from hydrate reservoirs, CO2 sequestration, and flow assurance. The observations of CH4-CO2 hydrates formed in NaCl solutions are limited at high-pressure and high-temperature conditions. In this work, a high-pressure experimental apparatus is built to investigate the phase behavior of CH4-CO2 hydrates. The interfacial phenomenon is observed during hydrate formation and dissociation. The phase boundary of CH4-CO2 hydrates is determined by using the isochoric pressure-search method with pressure above 10 MPa. A novel theoretical model is developed to calculate the phase boundary pressure of hydrates by implementing a modified PR EoS for the fluid phases, the van der Waals-Platteeuw model for the hydrate phase, and the Pitzer model for the effect of ions. It is revealed that the roughness of water–gas interface is greatly increased at the initial hydrate formation stage due to the occurrence of fine pillars at the interface, which is explained by two hypotheses, i.e., the non-equilibrium state of gas and water phases and the non-uniform lateral growth of hydrates at the interface. The roughness decreases as time goes by during hydrate formation owing to the thickness growth of the hydrate film. The deviation of the calculated phase boundary pressure from the 86 collected experimental data points of CH4-CO2 hydrates formed in pure water is 3.7%, and is 5.3% for the 24 collected phase boundary data points of CH4-CO2 hydrates formed in the NaCl solutions, which proves the reliability of the newly developed model. The measured phase boundary data points of CH4-CO2 hydrates formed in NaCl solutions in this work extend the phase boundary pressure up to 61.99 MPa and the temperature to 295.09 K, which have filled the blank of the database in the high-pressure and high-temperature region. The deviations of the calculated phase boundary pressure from these two groups of measured ones are 8.9% and 6.2% respectively.

Composite Films Based on Polyvinyl Alcohol and Na-Carboxymethyl Cellulose for Separation

The possibility of using composite films based on polyvinyl alcohol (PVA) and Na-carboxymethylcellulose (Na-CMC) as a separating material is considered for nickel-zinc and silver-zinc batteries. The sorption properties and porous structure of PVA/Na-CMC composite films treated with potassium hydroxide, as well as the electrochemical characteristics of nickel-zinc battery cells (open circuit voltage, average discharge voltage, charge retention) were investigated. The fundamental possibility of using PVA/Na-CMC composite films instead of a cellulose hydrate film is shown as a separating material for nickel-zinc and silver-zinc batteries.

Surface modified zero-valent aluminum for Cr(VI) removal at neutral pH

Zero-valent aluminum has attracted considerable attention in degradation of organic contaminants and reduction of heavy metal ions due to its very low redox potential (E0(Al3+/Al0) = −1.662 V). Usually there is a passive oxide film on Al surface, inhibiting its electron transfer and leading to low reaction efficiency. In this work, metal Al surface was modified by loose fine Al2O3 (SM-Al) using a procedure of soaking Al powder in water for a time period and then heat-treating in vacuum. It was found that surface modification remarkably enhanced the reaction efficiency of zero-valent Al in reduction of Cr(VI) to Cr(III) ions in aqueous solution. The longer the soaking time of Al powder in water is, the higher the efficiency in removing Cr(VI) is. The effects of Al particle size and dosage, initial Cr(VI) concentration and reaction temperature on Cr(VI) removal were investigated as well. XPS analyses revealed that the decrease in thickness of Al surface passive oxide films and the promotion of surface covered loose Al2O3 phases on hydration of passive oxide films are two main reasons responsible for the rapid removal of Cr(VI) by SM-Al. Meanwhile, SM-Al exhibited an excellent recyclability and the reused SM-Al has a very fast reaction rate relative to as-prepared SM-Al, 80% of Cr(VI) can be removed even it was reused up to five cycles. The present study provides a new route to activate Al in removal of contaminants in aqueous solution.

Effect of Bubble Surface Properties on Bubble–Particle Collision Efficiency in Froth Flotation

In research on the particle–bubble collision process, due to the adsorption of surfactants and impurities (such as mineral particles, slime, etc.), most studies consider the bubble surface environment to be immobile. However, in the real situation of froth flotation, the nature of the bubble surface (degree of slip) is unknown. Mobile surface bubbles increase the critical thickness of the hydration film rupture between particles and bubbles, and enhance the collision between particles and bubbles. Sam (1996) showed that when the diameter of the bubble is large enough, a part of the surface of the bubble can be transformed into a mobile state. When the bubble rises in a surfactant solution, the surface pollutants are swept to the end of the bubble, so when the bubble reaches terminal velocity, the upper surface of the bubble is changed into a mobile surface. This paper analyzes the collision efficiency and fluid flow pattern of bubbles with mobile and immobile surfaces, and expounds the influence of surface properties on collision efficiency.

A predictive model for the thermal conductivity of silty clay soil based on soil porosity and saturation

Soil thermal conductivity is a property that represents a soil’s capability of transferring energy and has been a common subject of study in soil science, geotechnical engineering, and geology. In this study, the quantitative effects of density, water content, saturation, and porosity on thermal conductivity of soil in Fengxian County are investigated by the field and laboratory tests. A new model for predicting soil thermal conductivity from its porosity, saturation, and quartz content is developed. In the field test, the thermal conductivity has a linear relationship with water content due to the increase in thickness of hydration film which decreases the thermal contact resistance between particles. A good logarithmic function is found for the relationship between thermal conductivity and natural density of silty clay soil in Fengxian County. In the laboratory test, there is a linear function for the relationship between thermal conductivity and density of silty clay soil. The thermal conductivity linearly increases with water content and decreases slightly when water content exceeds 17.65% due to the decreased density. The predicted thermal conductivity with the new model is compared with measured thermal conductivity from the field and laboratory tests. The root mean square error (RMSE) of the new model is 0.098 and 0.096 W m−1 K−1, respectively, which indicates that the new model provides accurate approximations of soil thermal conductivity in Fengxian County, China.

Impact of biodegradation of oil on the kinetics of gas hydrate formation and decomposition

Nowadays the biological methods based on utilization of bacteria for different purposes in oilfields are becoming more and more popular because these methods potentially may become a cheaper alternative to chemical treatments. Gas hydrates formation in pipelines is the one of the main flow assurance problems. In previous works it has been shown that some biodegraded oils can have components that may act as natural Anti-Agglomerants. These natural Anti-Agglomerants can prevent hydrate particles from agglomeration which allow the particles to flow downstream along with oil in form of slurry. But there is lack of understanding of how products of oil biodegradation affect the kinetic aspects of hydrate nucleation, formation and decomposition. This information might be useful for development of new approached of treatment of the hydrate related issues in oil pipelines.Impact of the changes in component composition of crude oil caused by biodegradation process on the kinetics of gas hydrates nucleation, formation and decomposition has been studied with different methods. It was demonstrated that the changes of chemical composition of crude oil caused by biodegradation can have a strong impact on the hydrate nucleation rates at static conditions. Almost twofold decrease of hydrate nucleation rate was observed in the experiments with the water-in-oil emulsion for the biodegraded oils compared to one obtained with emulsion in the original crude oil. At the same time, no significant effect of biodegradation on the hydrate film growth rates at static conditions was observed. Similar tangential and normal hydrate film growth rates were obtained in experiments with both crude oil and with biodegraded oil. Initial growth rates of hydrate in stirring emulsions were an order of magnitude higher for water emulsions in the biodegraded oil compared to ones for the original crude oil. The studies of the decomposition rates of hydrates at sub-zero temperatures and at dynamic conditions showed that the products of vital activity of bacteria promoted self-preservation of hydrates dispersed in the biodegraded oil.

Therapeutic Potential of Melaleuca alternifolia Essential Oil in New Drug Delivery Systems.

Medicinal plants produce secondary metabolites with special biological activities, which may be used as new therapeutic alternatives. For instance, tea tree essential oil (TTO) was shown to exert antimicrobial, antifungal, anthelmintic, antiviral, anti-tumor and anti-inflammatory activities. Due to their thermal instability, active principles can be easily degraded by physicochemical processes; therefore, they must be protected to increase their time of action and improve their controlled release. The aim of this review is to discuss formulations incorporating encapsulated TTO as the active ingredient. Micro and nanoencapsulated systems proved to be more thermostable than TTO and to exert better antimicrobial, antifungal, antiparasitic and larvicidal effects. Nanoencapsulation also reduced oil toxicity. Emulsified and hybrid systems developed by various methods showed improved repellent, antibacterial, antifungal and anti-inflammatory activities, thereby proving promising for the pharmaceutical industry. Liposomal formulations produced by hydration of lipid films exhibited constant rate of terpinen-4-ol release. In addition, their incorporation into biomaterials, such as sponges, nanofibers and films, showed great potential for treating infections. Mainly due to the advantages of their incorporation into new drug delivery systems over conventional formulations, there is an interest in the development of systems containing TTO as a pharmaceutical ingredient of plant origin.

In situ molecular imaging of adsorbed protein films in water indicating hydrophobicity and hydrophilicity

In situ molecular imaging of protein films adsorbed on a solid surface in water was realized by using a vacuum compatible microfluidic interface and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Amino acid fragments from such hydrated protein films are observed and identified in the positive ion mode and the results are in agreement with reported works on dry protein films. Moreover, water clusters from the hydrated protein films have been observed and identified in both the positive and negative ion mode for a series protein films. Thus, the detailed composition of amino acids and water molecules in the hydrated protein films can be characterized, and the protein water microstructures can be revealed by the distinct three-dimensional spatial distribution reconstructed from in situ liquid ToF-SIMS molecular imaging. Furthermore, spectral principal component analysis of amino acid fragment peaks and water cluster peaks provides unique insights into the water cluster distribution, hydrophilicity, and hydrophobicity of hydrated adsorbed protein films in water.

Nanoscale insights on the interface between passive film of steel and cement hydrate: Diffusion, kinetics and mechanics

The interfacial region between concrete and steel reinforcement (SCI) determines strength and durability of reinforced concrete structure. In this work, the molecular dynamics simulations were employed for understanding the bonding mechanism of SCI region. In the interfacial region, the calcium ions play the mediation of bonding CSH surface and the passivation film by combing the oxygen atoms and hydroxyl groups of CSH in the nearest neighbors. The hydroxyl groups in the γ-FeOOH and the unbinding O atom in the CSH provide enough oxygen sites to form the hydrogen bonds and hydration, which also improve the bond strength of the interlayer region. Furthermore, introducing single-layer water results in the hydrated Ca2+-water cluster formation, weakening the CaO connectivity between CSH and passive film. Double-layer water can significantly increase the diffusion of interfacial components and decrease the stability of interfacial bonds. In addition, simulated pull-out test and uniaxial tensile test were performed to evaluate bond strength of CSH and γ-FeOOH. Hydrolytic weakening is found due to water ingress in the interfacial region. Double-layer water penetration results in reduction of interfacial shear strength from 0.53 GPa to 0.38 GPa. Also, the Young’s modulus and cohesive strength reduced by more than 50% percentage. This work is expected as an important reference for design and development of reinforced concrete in engineering application.

Studying interactions between undecane and graphite surfaces by chemical force microscopy and molecular dynamics simulations

Collectors are often used to increase the hydrophobicity of valuable minerals during flotation. Hence, it is necessary to know the forces between them, especially the hydrophobic force, which closely associated with hydrophobic minerals floating, such as graphite, coal, and molybdenite. In the present study, graphite sheets were used as the hydrophobic mineral, and the force characteristics and interfacial adsorption structures of undecane (a model collector) on graphite surface with different hydrophobicities were investigated by chemical force microscopy and molecular dynamics simulations. Undecane experiences repulsive interactions as it approaches hydrophilic graphite; however, an obvious jump-in phenomenon driven by hydrophobic force was observed for hydrophobic graphite, which triggers their adhesion. Derjaguin–Landau–Verwey–Overbeek (DLVO) and extended DLVO fitting reveal that the hydrophobic force decays at 1.35 nm in a single-exponential manner. The adhesion force during retraction increases with increasing surface hydrophobicity. The hydrophilic surface adsorbs a large amount of water to form a dense and ordered hydration film that interferes with the adsorption of undecane, while a water-depletion layer exists on the hydrophobic surface with closely adsorbed undecane molecules. This study improves our understanding of the action mechanism of flotation collectors for hydrophobic minerals.

Hydrate Nucleation, Growth, and Induction.

The first stage of any phase transition is a dynamic coupling of transport processes and thermodynamic changes. The free energy change of the phase transition must be negative and large enough to also overcome the penalty work needed for giving space to the new phase. The transition from an unstable situation over to a stable growth is called nucleation. Hydrate formation nucleation can occur along a variety of different routes. Heterogeneous formation on the interface between gas (or liquid) and water is the most commonly studied. A hydrate can also form homogeneously from dissolved hydrate formers in water, and the hydrate can nucleate toward mineral surfaces in natural sediments or a pipeline (rust). A hydrate particle’s critical size is the particle size needed to enter a region of stable growth. These critical sizes and the associated nucleation times are nanoscale processes. The dynamics of the subsequent stable growth can be very slow due to transport limitations of hydrate-forming molecules and water across hydrate films. Induction times can be defined as the time needed to reach a visible hydrate. In the open literature, these induction times are frequently misinterpreted as nucleation times. Additional misunderstandings relate to the first and second laws of thermodynamics and the number of independent thermodynamics variables. It is not possible to reach thermodynamic equilibrium in systems where hydrates form in a pipeline or in sediments. Finally, there are common misconceptions that only one type of hydrate will form. In a non-equilibrium situation, several hydrates will form, depending on which phases the hydrate formers and water come from. In this paper, we utilize a simple nucleation theory to illustrate nucleation and growth of some simple hydrates in order to illustrate the non-equilibrium nature of hydrates and the fast nucleation times. To illustrate this, we apply thermodynamic conditions for a real pipeline transporting natural gas from Norway to Germany. This specific example also serves as a case for illustration of the possible impact of rusty pipeline surfaces in kicking out water from the gas. Specifically, we argue that the tolerance limit for water concentration according to current industrial hydrate risk practice might overestimate the tolerance by a factor of 20 as compared to tolerance concentration based on adsorption on rust.

Insight into Hydrate Film Growth: Unusual Growth of Methane Hydrate Film at the Interface of Methane and the Aqueous Solution of Malonic Acid

In this paper, we argue there is a new way of growing hydrate film other than two currently known ones, namely, a hydrate shell on the water surface without a surfactant and various hydrate dendrim...

Optimized Double Manganese Oxide Deposition for Enhanced Electrochemical Capacitor Performance

Manganese oxide pseudocapacitive materials are deposited using a novel procedure involving first depositing a heat-treated base layer followed by a hydrous top layer. The ratio of heat-treated to hydrous film is optimized to generate films that excel across a wide range of electrochemical capacitor (EC) properties and to elucidate the mechanisms underpinning the film performance. We show that a thin heat-treated base layer imparts low resistance, high energy efficiency and power-capability and enhanced film stability in a large potential window. These benefits are due to an improved oxide-current collector connection; however, if the layer is too thin (<25 nm), the stability is lost. Conversely, heat-treatment causes more parasitic oxidation reactions during initial film cycling, though these reactions are mitigated with a thick hydrous top layer. This hydrous film also affords high capacitance, capacity, coulombic efficiency and energy density due to an abundance of hydrated sites in the oxide to facilitate the cation insertion/removal needed for pseudocapacitance. The double-deposited films also show less self-discharge. We find that a dry:wet film ratio of 5:95 results in optimal film performance. While this novel dry-wet double-deposition has been demonstrated with manganese oxide, we anticipate similar performance benefits with other pseudocapacitive materials.

Применение гидратцеллюлозной пленки для исследования роста и развития корневой системы модельного растения Arabidopsis thaliana L.

A new technique for Arabidopsis thaliana cultivation has been proposed that combines the use of a phytogel-based nutrient medium and a hydrophilic membrane of hydrate cellulose film, separating the root system of the plant from the medium thickness. Growth rates of both main and lateral roots were faster in the plants cultivated on the surface of hydrate cellulose film than in the plants grown in the phytogel volume. The location of the root system on the surface of the transparent hydrate film simplifies its observation and analysis and facilitates plant transplantation with preservation of the root system configuration. The proposed technique allowed us to first assess the effect of exogenous auxin on the growth of lateral roots at the 5-6 developmental stage. methods to study plant root systems, hydrate cellulose film, A. thaliana, lateral roots, differential root growth rate, auxin The work was financially supported by the Russian Foundation for Basic Research (Project Bel_mol_a 19-54-04015) and the basic topic of the Russian Academy of Sciences - IBMP RAS «Regularities of the Influence of Extreme Environmental Factors on the Processes of Cultivation of Higher Plants and the Development of Japanese Quail Tissues at Different Stages of its Ontogenesis under the Conditions of Regenerative Life Support Systems».

Effects of inhibitors on the morphology and kinetics of hydrate growth on surface of bubble

This study provided direct evidences for the evolution of the growth modes, morphology, lateral growth rate and the mass transfer channels during the thickening growth of hydrates on gas (CH4 – C3H8) bubble suspended in water with inhibitors. Uniform and dense hydrate film was observed on the bubble and at the gas-liquid planar interface during thickening growth in absence of inhibitor (Growth Mode 1), but the film was heterogeneous when low concentration kinetic inhibitor was added (Growth Mode 2) and even not able to form when high concentration thermodynamic inhibitor was added (Growth Mode 3). In the Growth Mode 2, the adsorption of inhibitor on the frontier of the hydrate film destroyed the continuity of the hydrate growth and decreased the lateral growth rate of the hydrate film on the bubble. Moreover, the heterogeneousness resulted in numerous cross-shaped or circular craters on the film, which served a new mass transfer channel and accelerated the initial thickening growth of the hydrate. In the Growth Mode 3, the evolution of the hydrate morphology was correlated to the viscosity of the hydrate formed in the reaction systems and the spreading ability of the aqueous solution on the reactor wall. To the best of our knowledge, this was the first study on the microscopic effects of inhibitors on the kinetics of the hydrate growth on gas bubbles, which is of added value for better understanding the hydrate evolution process in the hydrate inhibition scenarios with gas bubbles.

Hydrate Growth on Methane Gas Bubbles in the Presence of Salt.

Methane bubble dispersions in a water column can be observed in both vertical subsea piping as well as subsea gas seepages. Hydrate growth has been shown to occur at the gas-water interface under flowing conditions, yet the majority of the current literature is limited to quiescent systems. Gas hydrate risks in subsea piping have been shown to increase in late life production wells with increased water content and with gas-in-water bubble dispersions. The dissolution of subsea methane seepages into seawater, or methane release into the atmosphere, can be affected by hydrate film growth on rising bubbles. A high-pressure water tunnel (HPWT), was used to generate a turbulent, continuous water flow system representative of a vertical jumper line to study the relationship between bulk methane hydrate growth and bubble size during a production-well restart. The HPWT comprises a flow loop of 19.1 mm inner diameter and 4.9 m length, with a vertical section containing an optical window to enable visualization of the bubble and hydrate flow dynamics via a high-speed, high-resolution video camera. Additional online monitoring includes the differential pressure drop, viscosity, temperature, flow rates, and gas consumption. Experimental conditions were maintained at 275 K and 6.2 MPa during hydrate formation and 298 K and 1.4 MPa during hydrate dissociation. Hydrate growth using freshwater and saltwater (3.5 wt % NaCl) was measured at four flow velocities (0.8, 1.2, 1.6, and 1.9 m s-1). The addition of salt is shown in this work to alter the surface properties of bubbles, which introduces changes to bubble dynamics of dispersion and coalescence. Hydrate volume fractions and growth rates in the presence of salt were on average ∼32% lower compared to that in freshwater. This was observed and validated to be due to bubble size and dynamic factors and not due to the 1.5 K thermodynamic inhibition effect of salt. Throughout hydrate growth, methane bubbles in pure freshwater maintained larger diameters (2.4-4.2 mm), whereas the presence of salt promoted fine gas bubble dispersions (0.1-0.7 mm), increasing gas-water interfacial area. While gas bubble coalescence was observed in all freshwater experiments, the addition of salt limited coalescence between gas bubbles and reduced bubble size. Consequently, earlier formation of solid hydrate shells in saltwater produced early mass-transfer barriers reducing hydrate growth rates. While primarily directed toward flow assurance, the observed relationship between hydrates, bubble size, and saltwater also applies to broader research fields in subsea gas seepages and naturally occurring hydrates.

IRGD-guided tamoxifen polymersomes inhibit estrogen receptor transcriptional activity and decrease the number of breast cancer cells with self-renewing capacity

BackgroundTamoxifen (Tam) is the most frequent treatment for estrogen receptor (ER) positive breast cancer. We recently showed that fibronectin (FN) leads to Tam resistance and selection of breast cancer stem cells. With the aim of developing a nanoformulation that would simultaneously tackle ER and FN/β1 integrin interactions, we designed polyethylene glycol-polycaprolactone polymersomes polymersomes (PS) that carry Tam and are functionalized with the tumor-penetrating iRGD peptide (iRGD-PS-Tam).ResultsPolyethylene glycol-polycaprolactone PS were assembled and loaded with Tam using the hydration film method. The loading of encapsulated Tam, measured by UPLC, was 2.4 ± 0.5 mol Tam/mol polymer. Physicochemical characterization of the PS demonstrated that iRGD functionalization had no effect on morphology, and a minimal effect on the PS size and polydispersity (176 nm and Pdi 0.37 for iRGD-TAM-PS and 171 nm and Pdi 0.36 for TAM-PS). iRGD-PS-Tam were taken up by ER+ breast carcinoma cells in 2D-culture and exhibited increased penetration of 3D-spheroids. Treatment with iRGD-PS-Tam inhibited proliferation and sensitized cells cultured on FN to Tam. Mechanistically, treatment with iRGD-PS-Tam resulted in inhibition ER transcriptional activity as evaluated by a luciferase reporter assay. iRGD-PS-Tam reduced the number of cells with self-renewing capacity, a characteristic of breast cancer stem cells. In vivo, systemic iRGD-PS-Tam showed selective accumulation at the tumor site.ConclusionsOur study suggests iRGD-guided delivery of PS-Tam as a potential novel therapeutic strategy for the management of breast tumors that express high levels of FN. Future studies in pre-clinical in vivo models are warranted.

A precise deconvolution method to derive methane hydrate cage occupancy ratios using Raman spectroscopy

Raman spectroscopy was used to analyze cage occupancy of thin homogeneous methane hydrate (MH) films at (2.9 to 7.6) MPa and (273 to 276) K. The MH films were synthesized on the lower surface of a sapphire window of a high-pressure cell to eliminate noise associated with the CH stretching vibration of bulk methane gas. Methane medium-size to small-size cage occupancy ratios of the MH films were determined for purposes of assessing the reliability of deconvolution functions used in data reduction. Gaussian, Lorentzian and Voigt functions were considered and the Voigt function was found to provide the most reliable function in terms of fitting precision. Methane occupancy ratios tend to decrease with increasing pressure which is important for practical scale simulations.