Structural characterization of CdSe-doped Sol-Gel silicophosphate films

SiO₂-P₂O₅ films doped with CdSe have been prepared and investigated for temperature sensors applications. The films have been synthesized by sol-gel method, spin coating technique, the deposition being made on glass substrates. The sols have been prepared from tetraethylorthosilicate (TEOS) and phosphoric acid as precursors for SiO₂ and P₂O₅, respectively, together with ethanol and water as reaction environment and a hydrolysis reagent, respectively. The films have been deposited at three rotation rates: 1000, 2000 and 3000 rpm, starting on the first day after the sol preparation moment and going on, four days consecutively, and then on the eighth day. We have analyzed the influence of the rotation rate and the time elapsed since the sol preparation till the deposition moment on the structural properties of the doped films. The films deposited at each rotation rate have been annealed at 200, 300, 350, 400, and 550°C in order to investigate the structural modifications noticed during the formation process of silicophosphate network.     

Peptides from fish and crustacean by-products hydrolysates stimulate cholecystokinin release in STC-1 cells

Fish protein hydrolysates (FPH) are of significant interest, due to their potential application as a source of bioactive peptides in nutraceutical and pharmaceutical domains. Here, we investigated the action of FPH from blue whiting (Micromesistius poutassou) and brown shrimp (Penaeus aztecus) on cholecystokinin release from intestinal endocrine cells (STC-1). We demonstrated for the first time that FPH were able to highly stimulate CCK-releasing activity from STC-1 cells and that this stimulation was mainly due to peptide molecules. The partial purification of CCK-stimulating peptides showed that their apparent molecular weight ranged between 1000 and 1500 Da for fish and crustacean FPH, respectively. Finally, in an aim to industrially produce hydrolysates enriched in CCK-stimulating molecules, we tested the effects of membrane processes (ultrafiltration and nanofiltration) on active peptide enrichments.     

Crosslinked polysulfone obtained by Wittig‐Horner reaction in biphase system

Phase transfer catalyzed reactions are often more easily and cheaply performed than conventional method and they are therefore of particular interest. A polysulfone functionalized with phosphonate (2‐PSF) was prepared under phase transfer catalysis (PTC) conditions, and it was evaluated by spectrometric method (Fourier transform infrared spectroscopy, using potassium bromide (KBr) pellet). The phosphorus content of the modified polysulfone was determined, and it was used for the determination the fraction of repeating units functionalized with phosphonate groups. The modified polysulfone contains 1.40 mmol phosphonate/g polysulfone. Polysulfone functionalized with phosphonate groups and polysulfone functionalized with aldehyde groups (3‐PSF) were used in Wittig‐Horner reaction, to introduce double bonds on polymer and to obtain crosslinked polysulfone (4‐PSF). The reactions were performed using PTC method, solid‐liquid (potassium carbonate (K₂CO₃), tetrahydrofuran (THF), tetraethylammonium iodide (TEAI)) system. The structure of polysulfone functionalized with phosphonate groups and polysulfone functionalized with aldehyde group were confirmed by ¹H‐, ¹³C‐, and ³¹P‐nuclear magnetic resonance (NMR). The peak for phosphorus in PSF‐phosphonate appears in ³¹P NMR spectrum as a singlet at 25.712 ppm. The thermal properties of aldehyde, phosphonate, and crosslinked polysulfone were studied by thermogravimetric analysis (TG) and differential thermogravimetric analysis (DTG). Scanning electron microscopy images for polysulfone functionalized with phosphonate and crosslinked polysulfone are in concordance with nitrogen (N₂) adsorption‐desorption isotherms.POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Comparison of multiple chemical sanitizers for reducing Salmonella and Escherichia coli O157:H7 on spinach (Spinacia oleracea) leaves

Effectiveness of multiple chemical sanitizers on the reduction of Salmonella spp. and Escherichia coli O157:H7 on spinach was compared. Fresh spinach (Spinacia oleracea) was inoculated with a bacterial suspension containing multiple strains of rifampin-resistant Salmonella and E. coli O157:H7. Inoculated spinach leaves were treated with a water wash or water wash followed by 2% L-lactic acid at 55 °C, peroxyacetic acid (80 mg/L), calcium hypochlorite (200 mg/L), ozonated water (mg/L) or ClO₂ gas (1.2 or 2.1 mg/L). The l-lactic acid produced a 2.7 log CFU/g reduction for E. coli O157:H7 and a 2.3 log CFU/g reduction for Salmonella, statistically significant compared to water wash alone (P < 0.05), which resulted in a reduction of 0.7 log CFU/g for both pathogens. These findings indicate that 2% l-lactic acid at 55 °C may be an effective treatment for reducing pathogens on spinach leaves.     

Molecular assembly of multifunctional ⁹⁹(m)Tc radiopharmaceuticals using "clickable" amino acid derivatives

Synthetic strategies that enable the efficient and selective combination of different biologically active entities hold great promise for the development of multifunctional hybrid conjugates useful for biochemical and medical applications. Starting from side‐chain‐functionalized N(α)‐propargyl lysine derivatives, conjugates containing a ^99mTc‐based imaging probe for SPECT and two different moieties (e.g., tumor‐targeting vectors, pharmacological modifiers, affinity tags, or second imaging probes) can be assembled using the Cu^I‐catalyzed alkyne–azide cycloaddition in efficient one‐pot protocols. This strategy was successfully applied to the preparation of a ^99mTc‐labeled conjugate comprising a tumor‐targeting peptide sequence (bombesin(7–14)) and a low‐molecular‐weight albumin binder, a pharmacological modifier that prolongs the blood circulation time of the conjugate. Evaluation of the conjugate in vitro and in vivo provided promising results for its use as an imaging agent for the visualization of tumors positive for the gastrin‐releasing peptide receptor. The methodology presented herein provides an attractive synthetic tool for the preparation of multifunctional ^99mTc‐based radiopharmaceuticals with significant potential for a multitude of applications.     

Novel 3‐Carboxy‐ and 3‐Phosphonopyrazoline Amino Acids as Potent and Selective NMDA Receptor Antagonists: Design,Synthesis, and Pharmacological Characterization

The design and synthesis of new N1‐substituted 3‐carboxy‐ and 3‐phosphonopyrazoline and pyrazole amino acids that target the glutamate binding site of NMDA receptors are described. An analysis of the stereochemical requirements for high‐affinity interaction with these receptors was performed. We identified two highly potent and selective competitive NMDA receptor antagonists, (5S,αR)‐ 1 and (5S,αR)‐ 4 , which exhibit good in vitro neuroprotective activity and in vivo anticonvulsant activity by i.p. administration, suggesting that these molecules may have potential use as therapeutic agents.     

Highly Conducting Polypyrrole/Cellulose Nanocomposite Films with Enhanced Mechanical Properties

PPy was synthesised by oxidative chemical polymerisation using xylan, CMC and NFC as additives. Conducting nanocomposite films were cast from aqueous slurries using doped PPy particles, CMC and NFC as the conducting and reinforcing phase, respectively. NFC‐based composites had higher conductivity and lower mechanical properties than CMC‐based homologues. SEM analysis showed that in PPy/NFC composites, PPy and NFC were arranged in two entangled networks, whereas, in PPy/NFC composites, CMC formed a continuous matrix around PPy particles, thus limiting conductivity. Mechanical properties of nanocomposite films were interpreted as reflecting the presence of different structures when using NFC or CMC as reinforcing phase.

     

Urinary mycoestrogens, body size and breast development in New Jersey girls

Background

Despite extensive research and interest in endocrine disruptors, there are essentially no epidemiologic studies of estrogenic mycotoxins, such as zeranol and zearalenone (ZEA). ZEA mycoestrogens are present in grains and other plant foods through fungal contamination, and in animal products (e.g., meat, eggs, dairy products) through deliberate introduction of zeranol into livestock to enhance meat production, or by indirect contamination of animals through consumption of contaminated feedstuff. Zeranol is banned for use in animal husbandry in the European Union and other countries, but is still widely used in the US. Surprisingly, little is known about the health effects of these mycoestrogens, including their impact on puberty in girls, a period highly sensitive to estrogenic stimulation.

Objectives and methods

We conducted a cross-sectional analysis among 163 girls, aged 9 and 10 years, participating in the Jersey Girl Study to measure urinary mycoestrogens and their possible relationship to body size and development.

Results

We found that mycoestrogens were detectable in urine in 78.5% of the girls, and that urinary levels were predominantly associated with beef and popcorn intake. Furthermore, girls with detectable urinary ZEA mycoestrogen levels tended to be shorter and less likely to have reached the onset of breast development.

Conclusions

Our findings suggest that ZEA mycoestrogens may exert anti-estrogenic effects similar to those reported for isoflavones. To our knowledge, this was the first evaluation of urinary mycoestrogens and their potential health effects in healthy girls. However, our findings need replication in larger studies with more heterogeneous populations, using a longitudinal approach.     

Niemann-Pick C2 Protein Expression Regulates Lithogenic Diet-Induced Gallstone Formation and Dietary Cholesterol Metabolism in Mice

Niemann-Pick C2 protein (NPC2) is a lysosomal soluble protein that is highly expressed in the liver; it binds to cholesterol and is involved in intracellular cholesterol trafficking, allowing the exit of lysosomal cholesterol obtained via the lipoprotein endocytic pathway. Thus, this protein may play an important role in controlling hepatic cholesterol transport and metabolism. The aim of this work was to study the relevance of NPC2 protein expression in hepatic cholesterol metabolism, biliary lipid secretion and gallstone formation by comparing NPC2 hypomorph [NPC2 (h/h)] and wild-type mice fed control, 2% cholesterol, and lithogenic diets. NPC2 (h/h) mice exhibited resistance to a diet-induced increase in plasma cholesterol levels. When consuming the chow diet, we observed increased biliary cholesterol and phospholipid secretions in NPC2 (h/h) mice. When fed the 2% cholesterol diet, NPC2 (h/h) mice exhibited low and high gallbladder bile cholesterol and phospholipid concentrations, respectively. NPC2 (h/h) mice fed with the lithogenic diet showed reduced biliary cholesterol secretion, gallbladder bile cholesterol saturation, and cholesterol crystal and gallstone formation. This work indicates that hepatic NPC2 expression is an important factor in the regulation of diet-derived cholesterol metabolism and disposal as well as in diet-induced cholesterol gallstone formation in mice.     

A New Family of Conformationally Constrained Bicyclic Diarylprolinol Silyl Ethers as Organocatalysts

Simple chemical manipulations of trans‐4‐L ‐hydroxy proline allow the access to a new family of bicyclic silyl ether organocatalysts that display some remarkable features. Apart from being extremely stable to hydrolytic conditions and possessing excellent catalytic performances, the rigidity of the bicyclic structure imposes a synclinal endo disposition of the bulky substituents with respect to the pyrrolidine ring, opposed to the more stable synclinal exo conformations of Jørgensen–Hayashi catalysts.