Low temperature synthesis of magnetite and maghemite nanoparticles

We report on the synthesis of iron oxide nanoparticles below 100 degrees C by a simple chemical protocol. The uniqueness of the method lies in the use of Ferrous ammonium sulphate (in conjugation with FeCl3) which helps maintain the stability of Fe2+ state in the reaction sequence thereby controlling the phase formation. Hexamine was added as the stabilizer. The nanoparticles synthesized at three different temperatures viz, 5 degrees, 27 degrees, and 95 degrees C are characterized by several techniques. Generally, when a mixture of Fe3+ and Fe2+ is added to sodium hydroxide, alpha-Fe2O3 (the anti-ferromagnetic phase) is formed after the dehydration process of the hydroxide. In our case however, the phases formed at all the three temperatures were found to be ferro (ferri) magnetic, implying modification of the formation chemistry due to the specifics of our method. The nanoparticles synthesized at the lowest temperature exhibit magnetite phase, while increase in growth temperature to 95 degrees C leads to the maghemite phase.     

New Silicone Composites for Dielectric Elastomer Actuator Applications In Competition with Acrylic Foil

Several polydimethylsiloxane elastomers were developed and investigated regarding their potential use as materials in dielectric elastomer actuators (DEA). A hydroxyl end‐functionalized polydimethylsiloxane was reacted with different crosslinkers and the electromechanical properties of the resulting elastomers were investigated. The silicone showing the best actuation at the lowest electric field was further used as matrix and compounded with encapsulated conductive polyaniline particles. These composites have enhanced properties including increased strain at break, higher dielectric constant as well as, gratifyingly, breakdown fields higher than that of the matrix. One of the newly synthesized composites is compared to the commercially available acrylic foil VHB 4905 (3M) which is currently the most commonly used elastomer for DEA applications. It was found that this material has little hysteresis and can be activated at lower voltages compared to VHB 4905. For example, when the newly synthesized composite was 30% prestrained, a lateral actuation strain of about 12% at 40 V μm^?1 was measured while half of this actuation strain at the same voltage was measured for VHB 4905 film that was 300% prestrained. It also survived more than 100 000 cycles at voltages which are close to the breakdown field. Such materials might find applications wherever small forces but large strains at low voltages are required, in, for example, tactile displays.     

A mouse model of spontaneous preterm birth based on the genetic ablation of biglycan and decorin

Preterm premature rupture of membranes is responsible for one-third of preterm births. Ehlers-Danlos syndrome (EDS) is associated with preterm premature rupture of membranes in humans. In particular, an EDS variant is caused by a genetic mutation resulting in abnormal secretion of biglycan and decorin, two small leucine-rich proteoglycans highly expressed in reproductive tissues. Because biglycan/decorin null mutant (Bgn(-/-)Dcn(-/-)) mice demonstrate phenotypic changes similar to EDS, we used this model to test whether either biglycan or decorin or both play a role in the attainment of successful term gestation. Wild-type biglycan null mutant, decorin null mutant, and biglycan/decorin null mutant pregnancies were assessed for the length of gestation, pup and placenta weight, and litter size. Quantitative real-time PCR was performed to measure biglycan and decorin gene expression, and immunohistochemistry was performed to assess protein expression in placenta and fetal membranes at embryonic days E12, E15, and E18. Bgn(-/-)Dcn(-/-) dams displayed preterm birth, whereas the possession of at least two biglycan or decorin wild-type alleles was protective of preterm birth. The number of Bgn(-/-)Dcn(-/-) pups was decreased at postnatal day P1 but not at E18. Biglycan and decorin were upregulated in the placenta in the absence of each other and were developmentally regulated in fetal membranes, suggesting that these two proteoglycans demonstrate genetic complementation and contribute to gestational success in a dose-dependent manner. Thus, the biglycan/decorin null mutant mouse is a model of genetically induced preterm birth and perinatal loss. This model presents novel targets for preventive or therapeutic manipulation of preterm birth.     

Quantification of Lactulose and Epilactose in the Presence of Lactose in Milk using a dual HPLC analysis

The valuable lactose derivatives lactulose and epilactose can be derived from lactose either by the Lobry de Bruyn-Alberda van Ekenstein transformation during heat treatments or by enzymatic conversion using cellobiose 2-epimerases (EC 5.1.3.11). The chromatographic determination of lactose, lactulose, and epilactose in milk is challenging, due to the variable ratio of the three saccharides and their similar retention properties. In this work, a dual high-performance liquid chromatography (HPLC) analysis for the quantification of lactose, lactulose, and epilactose in milk samples was developed and validated. The samples originated from an enzymatic lactose conversion using the cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus. Application of this enzyme led to the formation of high lactulose concentrations (28.0 g/L) in milk. The dual HPLC analysis utilized a combination of two chromatographic separation techniques, configured in two parallel systems. After precolumn derivatization, the samples were analyzed as follows: Method 1 determined the concentration of lactose and epilactose using a C₁₈ column with an ion-pair reagent as eluent, coupled with a UV detector. Method 2 determined the concentration of lactulose using a trimodal stationary phase (hydrophilic interaction, anion- and cation-exchange properties) with acetonitrile/ammonium formiate buffer as eluent, coupled with an evaporative light scattering detector. Both methods were validated in terms of linearity, precision and recovery. The revealing detection limits in the milk samples were 3.32 mg/L for lactose, 4.73 mg/L for epilactose and 139 mg/L for lactulose. The dual HPLC analysis presented allows accurate lactose, lactulose, and epilactose separation in complex food matrices such as milk.     

Improvement of bioactive phenol content in virgin olive oil with an olive-vegetation water concentrate produced by membrane treatment

Olive-vegetation water (OVW) is very rich in phenols, which can cause pollution problems, due to their high hydrophilicity and antimicrobial activity. In this study, a three-phase membrane system was applied for the recovery of hydrophilic phenols from fresh OVW in an industrial plant, through a prior enzymatic treatment. This innovation yielded both a crude phenolic concentrate (CPC) and a very high reduction in OVW pollution. Furthermore, the CPC was utilised in a virgin olive oil (VOO) extraction process with the aim of improving VOO phenolic content. The results obtained with four different olive cultivars showed that the CPC extraction increased the phenolic content of the VOOs without any alteration of their aroma profiles.     

Effects of selenium addition on minimally processed leafy vegetables grown in a floating system

BACKGROUND: In recent years the consumption of minimally processed leafy vegetables has been increasing. At the same time food quality and its effects on human health have become crucial issues. Since selenium (Se) is an important microelement due to its ability to defend human organisms against free radicals, we investigated the effects of Se on chicory and lettuce production, and assessed the feasibility of a floating system as a method of producing Se‐enriched vegetables. RESULTS: The addition of 0.5 and 1.0 mg Se L^?1 to the nutrient solution resulted in an increase in the selenium concentration in the leaves, which had a positive effect on the plant yield. Selenium was generally effective in decreasing the production of ethylene and phenylalanine ammonia lyase (PAL) activity, even though a seasonal effect seemed to be present, consequently improving the quality of leafy vegetables and the shelf life in both species. The amount of Se accumulated in plants grown in the nutrient solution containing 0.5 mg Se kg^?1 could provide the rational Se intake for human nutrition in accordance with the recommended dietary allowance (RDA) guidelines. CONCLUSIONS: The addition of Se in a nutrient solution can be a useful system for providing enriched leafy vegetables. The floating system can be used to modulate the availability of Se in nutrient solutions and to grow vegetables with the optimal Se content for human health. Copyright © 2009 Society of Chemical Industry     

Effects of Rare Phytocannabinoids on the Endocannabinoid System of Human Keratinocytes

The decriminalization and legalization of cannabis has paved the way for investigations into the potential of the use of phytocannabinoids (pCBs) as natural therapeutics for the treatment of human diseases. This growing interest has recently focused on rare (less abundant) pCBs that are non-psychotropic compounds, such as cannabigerol (CBG), cannabichromene (CBC), Δ⁹-tetrahydrocannabivarin (THCV) and cannabigerolic acid (CBGA). Notably, pCBs can act via the endocannabinoid system (ECS), which is involved in the regulation of key pathophysiological processes, and also in the skin. In this study, we used human keratinocytes (HaCaT cells) as an in vitro model that expresses all major ECS elements in order to systematically investigate the effects of CBG, CBC, THCV and CBGA. To this end, we analyzed the gene and protein expression of ECS components (receptors: CB₁, CB₂, GPR55, TRPV1 and PPARα/γ/δ; enzymes: NAPE-PLD, FAAH, DAGLα/β and MAGL) using qRT-PCR and Western blotting, along with assessments of their functionality using radioligand binding and activity assays. In addition, we quantified the content of endocannabinoid(-like) compounds (AEA, 2-AG, PEA, etc.) using UHPLC-MS/MS. Our results demonstrated that rare pCBs modulate the gene and protein expression of distinct ECS elements differently, as well as the content of endocannabinoid(-like) compounds. Notably, they all increased CB_1/2 binding, TRPV1 channel stimulation and FAAH and MAGL catalytic activity. These unprecedented observations should be considered when exploring the therapeutic potential of cannabis extracts for the treatment of human skin diseases.     

Design,Synthesis and Evaluation of Novel Molecular Hybrids between Antiglaucoma Drugs and H2S Donors

Glaucoma is a group of eye diseases consisting of optic nerve damage with corresponding loss of field vision and blindness. Hydrogen sulfide (H₂S) is a gaseous neurotransmitter implicated in various pathophysiological processes. It is involved in the pathological mechanism of glaucomatous neuropathy and exerts promising effects in the treatment of this disease. In this work, we designed and synthetized new molecular hybrids between antiglaucoma drugs and H₂S donors to combine the pharmacological effect of both moieties, providing a heightened therapy. Brinzolamide, betaxolol and brimonidine were linked to different H₂S donors. The H₂S-releasing properties of the new compounds were evaluated in a phosphate buffer solution by the amperometric approach, and evaluated in human primary corneal epithelial cells (HCEs) by spectrofluorometric measurements. Experimental data showed that compounds 1c, 1d and 3d were the hybrids with the best properties, characterized by a significant and long-lasting production of the gasotransmitter both in the aqueous solution (in the presence of L-cysteine) and in the intracellular environment. Because, to date, the donation of H₂S by antiglaucoma H₂S donor hybrids using non-immortalized corneal cells has never been reported, these results pave the way to further investigation of the potential efficacy of the newly synthesized compounds.