A Fast Determination of Chlorophylls in Barley Grass Juice Powder Using HPLC Fused-Core Column Technology and HPTLC

This work presents a novel approach to qualitative and quantitative evaluation of chlorophyll content in food supplement using simple and fast separation techniques (high performance liquid chromatography (HPLC) and high performance thin layer chromatography (HPTLC)). For the first time, an Ascentis® Express C-18 HPLC column (100?×?4.6 mm; 2.7 μm), based on fused-core particles, was utilised for the analysis of chlorophyll a and chlorophyll b in green young barley grass juice powder extracts. The mobile phase was composed of methanol, water and ethyl acetate of 40:10:50 (v/v/v) at a flow rate of 1.5 mL/min. Chlorophylls were separated in time less than 6 min. The extraction procedure was optimised by using of 90 % of acetone in water, and the method was validated. The method precision was found in the range of 1.15–2.85 %, and the method recovery was established at three concentration levels. Calibration graphs were linear in the range of 0.75–25.5 mg/L, with correlation coefficients r ²?=?0.99958 for chlorophyll a and r ²?=?0.99961 for chlorophyll b. The comparative HPTLC fingerprint analysis of three samples from different continents showed only slight qualitative differences between the particular samples. The results demonstrated that the proposed methods can be used as fast and powerful techniques for the characterisation of barley juice extracts in quality control.     

Optimization of powder injection molding of feedstock based on aluminum oxide and multicomponent water‐soluble polymer binder

Analyses crucial to optimize powder injection molding of feedstock based on aluminum oxide powder and multicomponent polymeric binder are provided with the aim to obtain defect‐free, high density parts. As the critical step of the process is the flow of highly filled (60 vol%) compound into a mold cavity, rheological properties supplemented by thermal and pressure‐volume‐temperature characteristics are measured and described. Upon shear deformation the feedstock undergoes structural changes, which are quantified in terms of yield stresses obtained using Herschel‐Bulkley and Casson methods. Further, the rheological model is developed to describe the flow behavior of the feedstock in the whole shear rate range measured. Thermogravimetric analysis is performed to optimize debinding step of the process, and two possible ways of the binder removal are proposed: purely thermal andcombined solvent/thermal. The quality of the final sintered parts is demonstrated on scanning electron microscopic images of their surfaces. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Sulfation of Phenolic Acids: Chemoenzymatic vs. Chemical Synthesis

Phenolic acids are known flavonoid metabolites, which typically undergo bioconjugation during phase II of biotransformation, forming sulfates, along with other conjugates. Sulfated derivatives of phenolic acids can be synthesized by two approaches: chemoenzymatically by 3′-phosphoadenosine-5′-phosphosulfate (PAPS)-dependent sulfotransferases or PAPS-independent aryl sulfotransferases such as those from Desulfitobacterium hafniense, or chemically using SO₃ complexes. Both approaches were tested with six selected phenolic acids (2-hydroxyphenylacetic acid (2-HPA), 3-hydroxyphenylacetic acid (3-HPA), 4-hydroxyphenylacetic acid (4-HPA), 3,4-dihydroxyphenylacetic acid (DHPA), 3-(4-hydroxyphenyl)propionic acid (4-HPP), and 3,4-dihydroxyphenylpropionic acid (DHPP)) to create a library of sulfated metabolites of phenolic acids. The sulfates of 3-HPA, 4-HPA, 4-HPP, DHPA, and DHPP were all obtained by the methods of chemical synthesis. In contrast, the enzymatic sulfation of monohydroxyphenolic acids failed probably due to enzyme inhibition, whereas the same reaction was successful for dihydroxyphenolic acids (DHPA and DHPP). Special attention was also paid to the counterions of the sulfates, a topic often poorly reported in synthetic works. The products obtained will serve as authentic analytical standards in metabolic studies and to determine their biological activity.     

Adaptive Synthesis of Functional Amphiphilic Dendrons as a Novel Approach to Artificial Supramolecular Objects

Supramolecular structures, such as micelles, liposomes, polymerosomes or dendrimerosomes, are widely studied and used as drug delivery systems. The behavior of amphiphilic building blocks strongly depends on their spatial distribution and shape of polar and nonpolar component. This report is focused on the development of new versatile synthetic protocols for amphiphilic carbosilane dendrons (amp-CS-DDNs) capable of self-assembly to regular micelles and other supramolecular objects. The presented strategy enables the fine modification of amphiphilic structure in several ways and also enables the facile connection of a desired functionality. DLS experiments demonstrated correlations between structural parameters of amp-CS-DDNs and the size of formed nanoparticles. For detailed information about the organization and spatial distribution of amp-CS-DDNs assemblies, computer simulation models were studied by using molecular dynamics in explicit water.     

The Role of MAPK3/1 and AKT in the Acquisition of High Meiotic and Developmental Competence of Porcine Oocytes Cultured In Vitro in FLI Medium

The developmental potential of porcine oocytes cultured in vitro was remarkably enhanced in a medium containing FGF2, LIF and IGF1 (FLI) when compared to a medium supplemented with gonadotropins and EGF (control). We analyzed the molecular background of the enhanced oocyte quality by comparing the time course of MAPK3/1 and AKT activation, and the expression of genes controlled by these kinases in cumulus-oocyte complexes (COCs) cultured in FLI and the control medium. The pattern of MAPK3/1 activation in COCs was very similar in both media, except for a robust increase in MAPK3/1 phosphorylation during the first hour of culture in the FLI medium. The COCs cultured in the FLI medium exhibited significantly higher activity of AKT than in the control medium from the beginning up to 16 h of culture; afterwards a deregulation of AKT activity occurred in the FLI medium, which was not observed in the control medium. The expression of cumulus cell genes controlled by both kinases was also modulated in the FLI medium, and in particular the genes related to cumulus-expansion, signaling, apoptosis, antioxidants, cell-to-cell communication, proliferation, and translation were significantly overexpressed. Collectively, these data indicate that both MAPK3/1 and AKT are implicated in the enhanced quality of oocytes cultured in FLI medium.     

Ash decline assessment in emerald ash borer-infested regions: A test of tree-level, hyperspectral technologies

The emerald ash borer (EAB) is an exotic insect pest currently threatening ash species in the Great Lakes region. Because of the potential impact on forests in this area, multiple government agencies are currently focusing their efforts on developing new technologies to detect, monitor and control this insect pest. Previous work has shown that hyperspectral remote sensing technologies can produce detailed maps of forest health and species abundance on a landscape scale. This study examines the capability of a commercially available sensor (SpecTIR VNIR) to map ash decline due to exotic EAB infestations in Michigan and Ohio. A 6-term linear regression equation based on known stress- and chlorophyll-sensitive indices was able to predict decline on a continuous 0- to 10 scale with an r-squared of 0.71 and an average jackknifed residual of 0.61. Treated as an integer, decline was predicted to within one class with 97% accuracy. The ability of this instrument to assess decline below class 4 (when dieback and transparency reach levels first noticeable in the field) is based upon pre-visual reductions in chlorophyll content and function that are characteristic of early stress. The identification of early stress is critical in containing newly introduced exotics such as EAB. While this decline prediction technique is not stress- or species-specific, it will enable land managers to assess and monitor detailed forest health across the landscape.     

Cervical cancer mortality in Belgium, 1955-1989. A descriptive study

This study describes trends in cervical cancer mortality among women in Belgium from 1954 to 1989. Data are analysed by means of the standardised mortality rate, age- and cohort-specific mortality rates and standardised cohort mortality ratios. The age-standardised mortality rate decreased progressively from 6.3/100,000 women-years in the first period (1955-1959) to 3.8/100,000 in 1985-1989, indicating a decline of 39.7% over the seven quinquennial periods. A decrease was observed in almost all age groups between 30 and 69 years. In the last 15 years, no further decline, but even a discrete increase, occurred for the age categories younger than 50 years. The successive cohorts born between 1915 and 1939 expressed a continuing lower risk of cervical cancer mortality. This trend was not observed for the most recent generations, for whom even a slight increase of the standardised cohort mortality ratio could be distinguished.     

Differences in characteristics of pellets prepared by different pelletization methods

Pellets are currently a very popular dosage form for oral application. They can be prepared by several pelletization techniques. Extrusion/spheronization, commonly used in the pharmaceutical industry, and modern agglomeration in a rotoprocessor were the methods chosen for pellet preparation in our study. Theophylline (in 10% to 65% concentration) was the model drug, lactose monohydrate was used as filler, microcrystalline cellulose Avicel® PH 101 was thespheronization enhancer, and the wetting agent was purified water. Both techniques led to the formation of pellets of appropriate shape and mechanical properties. Pellets of a higher density, hardness, lower friability, and slightly slower dissolution profiles were obtained by extrusion/spheronization. This method of pelletization also led to production of particles with narrower size distribution and bigger yield of pellets with the requested size.     

Adhesion and growth of vascular smooth muscle cells in cultures on bioactive RGD peptide-carrying polylactides

The surface of poly(l-lactide) (PLLA) films deposited on glass coverslips was modified with poly(dl-lactide) (PDLLA), or 1:4 mixtures of PDLLA and PDLLA-b-PEO block copolymers, in which either none, 5% or 20% of the copolymer molecules carried a synthetic extracellular matrix-derived ligand for integrin adhesion receptors, the GRGDSG oligopeptide, attached to the end of the PEO chain. The materials, perspective for vascular tissue engineering, were seeded with rat aortic smooth muscle cells (11,000 cells/cm²) and the adhesion, spreading, DNA synthesis and proliferation of these cells was followed on inert and bioactive surfaces. In 24-h-old cultures in serum-supplemented media, the number of cells adhering to the PDLLA-b-PEO copolymer was almost eight times lower than that on the control PDLLA surface. On the surfaces containing 5% and 20% GRGDSG-PEO-b-PDLLA copolymer, the number of cells increased 6- and 3-fold respectively, compared to the PDLLA-b-PEO copolymer alone. On PDLLA-b-PEO copolymer alone, the cells were typically round and non-spread, whereas on GRGDSG-modified surfaces the cell spreading areas approached those found on PDLLA, reaching values of 991 μm² and 611 μm² for 5% and 20% GRGDSG respectively, compared to 958 μm² for PDLLA. The cells on GRGDSG-grafted copolymers were able to form vinculin-containing focal adhesion plaques, to synthesize DNA and even proliferate in a serum-free medium, which indicates specific binding to the GRGDSG sequences through their adhesion receptors.