3,152 research outputs found

    High throughput microbalance and methods of using same

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    The method and apparatus is particularly adapted for providing microbalance measurement of solid materials as part of a combinatorial research program. The method and apparatus contemplate monitoring the response of a resonator holding a sample and correlating the response with mass change in the samples

    A combined phenotypic and metabolomic approach for elucidating the biostimulant action of a plant-derived protein hydrolysate on tomato grown under limited water availability

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    Plant-derived protein hydrolysates (PHs) are an important category of biostimulants able to increase plant growth and crop yield especially under environmental stress conditions. PHs can be applied as foliar spray or soil drench. Foliar spray is generally applied to achieve a relatively short-term response, whereas soil drench is used when a long-term effect is desired. The aim of the study was to elucidate the biostimulant action of PH application method (foliar spray or substrate drench) on morpho-physiological traits and metabolic profile of tomato grown under limited water availability. An untreated control was also included. A high-throughput image-based phenotyping (HTP) approach was used to non-destructively monitor the crop response under limited water availability (40% of container capacity) in a controlled environment. Moreover, metabolic profile of leaves was determined at the end of the trial. Dry biomass of shoots at the end of the trial was significantly correlated with number of green pixels (R2 = 0.90) and projected shoot area, respectively. Both drench and foliar treatments had a positive impact on the digital biomass compared to control while the photosynthetic performance of the plants was slightly influenced by treatments. Overall drench application under limited water availability more positively influenced biomass accumulation and metabolic profile than foliar application. Significantly higher transpiration use efficiency was observed with PH-drench applications indicating better stomatal conductance. The mass-spectrometry based metabolomic analysis allowed the identification of distinct biochemical signatures in PH-treated plants. Metabolomic changes involved a wide and organized range of biochemical processes that included, among others, phytohormones (notably a decrease in cytokinins and an accumulation of salicylates) and lipids (including membrane lipids, sterols, and terpenes). From a general perspective, treated tomato plants exhibited an improved tolerance to reactive oxygen species (ROS)-mediated oxidative imbalance. Such capability to cope with oxidative stress might have resulted from a coordinated action of signaling compounds (salicylic acid and hydroxycinnamic amides), radical scavengers such as carotenoids and prenyl quinones, as well as a reduced biosynthesis of tetrapyrrole coproporphyrins

    High throughput microbalance and methods of using same

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    A method and apparatus for measurement of mass of small sample sizes. The method and apparatus is particularly adapted for providing microbalance measurement of solid materials as part of a combinatorial research program. The method and apparatus contemplate monitoring the response of a resonator holding a sample and correlating the response with mass change in the samples

    A Review of Parameters and Mechanisms in Spray Cooling

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    Miniaturisation in avionics, electronics, and medical appliances has led to demands for rapid heat dissipation techniques. The spray cooling technique has gained importance recently due to its advantage over other cooling methods. Parameters affecting heat transfer mechanisms during spray cooling are contemplated. This review presents different heat transfer parameters and their effect on spray cooling by analysis from past studies. Heat transfer surface modifications and different coolant variations to enhance heat transfer effectiveness are also reviewed. Apart from high heat flux having more applications, low heat flux studies have also grabbed the researchers to find solutions with a temperature range lower than 250˚C. Therefore, the upcoming spray cooling technology will have broad applications that will contribute to the maximum efficiency of the heat removal rate

    Biostimulants in horticulture: evaluation of their mode of action on crops using a platform for high-throughput automated phenotyping

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    In the last decades, with the constant increase in world population, the fast reduction of fertile arable land and the deteriorating environmental conditions, optimization of agriculture has become a priority. The main focus is on increasing the final yield and protecting the crops from unfavourable growing conditions in a sustainable way. A possible solution to this problem is represented by biostimulants, bioactive substances of diverse origins. A very large number of new biostimulants enter the market every year. However, a thorough knowledge of the mode of action of the substances in different crops and in different environmental conditions is still lacking. Traditional testing methods are time-consuming, expensive and, in most cases, destructive. Therefore, in the last years high-throughput automated phenotyping platforms started to be considered an interesting alternative to traditional characterization assays, drawing the attention of biostimulant producers. Different cameras and sensors can be implemented into high-throughput phenotyping platforms, allowing to screen the effects of different substances on a large number of morpho-physiological plant traits in a fast, efficient, cost-effective and non-destructive manner. In our work, we developed a precise methodology to test the effects of a large set of protein hydrolysates on multiple plant species (wheat, Arabidopsis, lettuce and tomato) subjected to abiotic stresses (drought and salinity) at all phenological phases, from seed up to the crop maturity. A large number of morpho-physiological traits of the plants were analysed throughout their life cycle, before and after the application of the PHs substances. The original set of PHs has been subjected to an initial in vitro screening on Arabidopsis plantlets; the substances were applied as seed priming in three different concentrations. The best-performing PHs in control and salt stress conditions have then been used for trials in planta, where they were applied as foliar spray. With the use of a Plant Biostimulant Characterization Index (PBC), we were able to categorize the substances into functional classes according to their mode of action, classifying them as Growth Promoters and /or Stress Alleviators. Leaves of the plants treated with the best- and worst-performing substances were collected and subjected to untargeted metabolomic analysis to elucidate the biochemical pathways activated by the PHs applications. It was clear that the effects of the biostimulants on plants can vary depending on the mode and time of application, the growing conditions, the dose and the plant species they are applied to; therefore, before putting a new biostimulant on the market, it is essential to select the target crop species that could benefit from the treatment. High-throughput automated phenotyping platforms can be an extremely useful tool to speed up the testing process and precisely investigate the effects of the same substance on multiple morpho-physiological traits

    Employing Response Surface Methodology for the Optimization of Ultrasound Assisted Extraction of Lutein and β-Carotene from Spinach

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    Abstract: The extraction of lutein and β-carotene from spinach (Spinacia oleracea L.) leaves is important to the dietary supplement industry. A Box-Behnken design and response surface methodology (RSM) were used to investigate the effect of process variables on the ultrasound-assisted extraction (UAE) of lutein and β-carotene from spinach. Three independent variables, extraction temperature (°C), extraction power (%) and extraction time (min) were studied. Thin-layer chromatography (TLC) followed by UV visualization and densitometry was used as a simple and rapid method for both identification and quantification of lutein and β-carotene during UAE. Methanol extracts of leaves from spinach and authentic standards of lutein and β-carotene were separated by normal-phase TLC with ethyl acetate-acetone (5:4 (v/v)) as the mobile phase. In this study, the combination of TLC, densitometry, and Box–Behnken with RSM methods were effective for the quantitative analysis of lutein and β-carotene from spinach extracts. The resulting quadratic polynomial models for optimizing lutein and β-carotene from spinach had high coefficients of determination of 0.96 and 0.94, respectively. The optimal UAE settings for output of lutein and β-carotene simultaneously from spinach extracts were an extraction temperature of 40 °C, extraction power of 40% (28 W/cm3) and extraction time of 16 min. The identity and purity of each TLC spot was measured using time-of-flight mass spectrometry. Therefore, UAE assisted extraction of carotenes from spinach can provide a source of lutein and β-carotene for the dietary supplement industr

    Materials for Fusion Applications

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    An overview of materials foreseen for use or already used in fusion devices is given. The operating conditions, material requirements and characteristics of candidate materials in several specific application segments are briefly reviewed. These include: construction materials, electrical insulation, permeation barriers and plasma facing components. Special attention will be paid to the latter and to the issues of plasma-material interaction, materials joining and fuctionally graded interlayers

    Distance Sensing with Dynamic Speckles

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    Study to design stable lansoprazole pellets

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    Pharmaceutical product development is a complex and creative design process, that involves many factors, many unknowns, many disciplines and has a multiple iterations and a long lifecycle. In the development of pharmaceutical dosage forms, one of persistent challenges is getting an early stability assessment providing an understanding of critical formulation and process parameters. In depth and science based knowledge, whether to use one excipient or another, or to apply one process before the other, could help shortening the process time and as a consequence save the money which is one of the goals of pharmaceutical industry. Pelletization processes are usually lengthy and expensive. Processing of a single batch may sometimes require hours or even days to be completed, and it can result in a non-robust process. Formulation of a stable delivery system for lansoprazole is extremely difficult. Lansoprazole belongs to class II drugs of the Biopharmaceutical Classification System (BCS), characterized by low solubility and high permeability. Furthermore, lansoprazole degrades in a highly acidic and highly basic environment, and it is also unstable under conditions of high temperature and also high humidity, with a decrease in the amount of lansoprazole and discoloration of the material being noted on storage under such conditions Tetsuro et al., 1992. Additionally, a strong pH-dependent solubility of the drug was observed. There is therefore a need for a pharmaceutical delivery system which protects the active substance both during storage as well as the passage through the stomach. The aim of this study was on the one hand the multifactorial investigation of crucial parameters involved in the stability of lansoprazole pellets focusing on the formulation parameters and preparation technique and on the other hand application of Arrhenius equation as a comparative technique in stability of pellets as a solid dosage form. Firstly, thermal characterization of lansoprazole has been conducted in order to clarify the differences reported in the literature and elucidate the reason of the uncommon behaviour when different heating rates were applied. Combining a differential scanning calorimeter (DSC), thermogravimetric analysis (TGA) and hot-stage microscopy (HSM) technique, the results confirmed that the melting point depression at low heating rates was due to eutectic behavior of the drug with its decomposition products formed at low heating rates. Even when the high heating rates (30 and 40°C/min) were applied melting point of lansoprazole did not show independence on the heating rate and difference in the melting point was 1°C. Combination of different techniques and highly dynamic and standardized methods for determination of thermal properties of decomposable substances should be used. Series of experiments were devised to study the effects of various formulation and processing variables on preparation and the stability of lansoprazole in order to examine some of the precautions which can be taken to minimize the loss of activity. Lansoprazole pellets were prepared using two different pelletizing techniques, solution suspension layering in bottom spraying fluidized bed and direct pelletization in rotor processor. Firstly, in a solution suspension layering, influence of type of neutral pellet (sugar based and microcrystalline cellulose based), type of stabilizing agent (influence of neutral and weak basic microenvironmental pH), presence of protective HPMC coating, type of aqueous enteric polymer based on shellac or methacrylic acid copolymer (Marcoat 125® or Eudragit L30 D-55®) and the coating levels on surface morphology, porosity, dissolution and stability of enteric coated pellets containing acid-liable drug, was evaluated. Furthermore, the aim was to investigate the feasibility of rotary processor for preparing lansoprazole loaded pellets based on Balocel®, which is a pre-mixed excipient blend containing microcrystalline cellulose, lactose and sodium carboxymethyl cellulose. Since pelletization in fluidized bed rotary processor is a multivariable process and the final characteristics of produced pellets are affected by several factors, in order to achieve a controlled, robust process and to optimize desired pellet properties, experimental design has been applied using expert design system STAVEX. The most important process variables related to the geometric mean diameter of lansoprazole pellets and the moisture content at the end of liquid addition phase, according to the pre-experiments, included spray rate and rotor speed, while the most influential formulation variable was a level of drug load. The study revealed that even though the process has been optimized to obtain pellets of optimum size and shape, another crucial property of pellets, dissolution, was disregarded and was confounded by another factor which could not be controlled (inlet air humidity) and which was not included in the design. This led to a conclusion, that no matter how comprehensive pre-experimental part of the design is, screening design should be applied. Accelerated degradation, studying the temperature effects in the presence of moisture on the degradation rate constant of lansoprazole in pellets prepared using different pelletization techniques, has been applied. In order to obtain rapid degradation with science based screening approach, Arrhenius equation has been used as a screening and comparative technique to describe a breakdown of lansoprazole in a solid dosage form and it has proved to be helpful tool in obtaining information on the most important formulation parameters and the optimum formulation of lansoprazole pellets for stability. Solution suspension layering technique proved to be more controllable process and more advantageous in terms of pellets size, shape and stability, but more time consuming in comparison to the direct pelletization. Study has confirmed that the key mechanism in obtaining a stabile lansoprazole delivery system is not only suppression of proton attacks but also a limitation of its solubility in the moisture layer, since it was found that in the pellets, lansoprazole degrades following apparent zero-order kinetics. With weak basic microenvironmental pH in the pellets it was possible to keep the degradation and solubility of lansoprazole on a low level. Sugar core stabilized lansoprazole in a way of incorporating the drug in the core forming a less porous active layer on the surface, disabling a contact of water and the active substance. Presence of the protective layer has been justified since it increased the stability of lansoprazole acting as a physical barrier between the drug and the free carboxyl groups of enteric coating polymer. Predicted shelf-lives of pellets on room temperature should be confirmed with the data obtained in a real time stability testing under the same conditions of relative humidity
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