Effects of protein-simulated body fluid mixing methods on characteristics of bone-like mineral

This study examined effects of protein mixing methods into modified simulated body fluid (mSBF) on the crystalline structure and morphology of bone-like mineral (BLM) coated on a poly(lactic-co-glycolic acid) template (PLGA). Using bovine serum albumin (BSA) as a model protein, four sample groups were prepared: the N-BLM group was coated by soaking substrates in mSBF without BSA; the B-BLM group was coated by soaking in mSBF with BSA added immediately before soaking; the Ca-BLM group was coated by soaking in Ca-mSBF prepared by premixing BSA with a CaCl₂ solution before preparing the mSBF; the P-BLM group was coated by soaking in P-mSBF made by premixing the BSA with a KH₂PO₄ solution. The B-BLM and Ca-BLM groups exhibited densely coated, thick BLM layers, whereas the P-BLM group exhibited loosely connected BLM clusters. The hydroxyapatite (HAp) crystallites of the B-BLM and Ca-BLM groups were aligned along the c-axis, but those of the P-BLM group were disordered and had a lower crystallinity. The alignment to the c-axis of Ca-BLM and the disordered orientation of P-BLM were caused by calcium ions bound to BSA in Ca-mSBF and phosphate ions bound to BSA in P-mSBF, respectively. These results show that the crystallinity and morphology of BLM can be controlled by the mixing of BSA in mSBF. The crystallinity of BLM is closely connected to its solubility. Therefore, the release characteristics of growth factors and cell regulation on BLM could be affected by the changes in the crystalinity of BLM.     

Environmentally Friendly Vegetable Oil Microemulsions Using Extended Surfactants and Linkers

Microemulsion formation of triglyceride oils at ambient conditions (temperature and pressure) and without the addition of co-oil and/or alcohols is challenging at best. Undesirable phases, such as macroemulsions, liquid crystals and sponge phases, are often encountered when formulating triglyceride microemulsions. The purpose of this study is to investigate the use of extended surfactants, lipophilic linkers, and hydrophilic linkers in enhancing triglyceride solubilization and interfacial tension reduction. We have studied two classes of extended surfactants, linear alkyl polypropoxylated sulfate (LAPS) surfactants and linear alkyl polypropoxylated ethoxylated sulfate (LAPES) surfactants. Linkers evaluated were oleyl alcohol (lipophilic linker), sodium mono and dimethyl naphthalene sulfonate (SMDNS), and polyglucoside (hydrophilic linkers). Oils studied include olive, peanut, soybean, canola and sunflower oils. The effect of electrolyte concentration on microemulsion phase behavior was studied. The microemulsion “fish” diagram was obtained by plotting the total surfactant and linker concentrations versus the electrolyte concentration. We were able to form Winsor Type I, II, III and IV microemulsions at ambient conditions and without co-oil or short and medium chain length alcohol addition. Winsor Type III and IV triglyceride microemulsions are particularly useful in numerous applications such as cosmetics, vegetable oil extraction and soil remediation.

Suppression of LPS-Induced Inflammation and Cell Migration by Azelastine through Inhibition of JNK/NF-κB Pathway in BV2 Microglial Cells

The c-Jun N-terminal kinases (JNKs) are implicated in many neuropathological conditions, including neurodegenerative diseases. To explore potential JNK3 inhibitors from the U.S. Food and Drug Administration-approved drug library, we performed structure-based virtual screening and identified azelastine (Aze) as one of the candidates. NMR spectroscopy indicated its direct binding to the ATP-binding site of JNK3, validating our observations. Although the antihistamine effect of Aze is well documented, the involvement of the JNK pathway in its action remains to be elucidated. This study investigated the effects of Aze on lipopolysaccharide (LPS)-induced JNK phosphorylation, pro-inflammatory mediators, and cell migration in BV2 microglial cells. Aze was found to inhibit the LPS-induced phosphorylation of JNK and c-Jun. It also inhibited the LPS-induced production of pro-inflammatory mediators, including interleukin-6, tumor necrosis factor-α, and nitric oxide. Wound healing and transwell migration assays indicated that Aze attenuated LPS-induced BV2 cell migration. Furthermore, Aze inhibited LPS-induced IκB phosphorylation, thereby suppressing nuclear translocation of NF-κB. Collectively, our data demonstrate that Aze exerts anti-inflammatory and anti-migratory effects through inhibition of the JNK/NF-κB pathway in BV2 cells. Based on our findings, Aze may be a potential candidate for drug repurposing to mitigate neuroinflammation in various neurodegenerative disorders, including Alzheimer’s and Parkinson’s diseases.     

Using Fish Sauce as a Substitute for Sodium Chloride in Culinary Sauces and Effects on Sensory Properties

Historically, fish sauce has been a standard condiment and ingredient in various Southeast Asian cuisines. Moreover, fish sauce imparts umami taste, which may enhance perceived saltiness in food. This quality suggests that fish sauce may be used as a partial substitute for sodium chloride (NaCl) in food preparation, which may present a valuable option for health‐conscious and salt‐restricted consumers. However, the degree to which NaCl can be decreased in food products without compromising taste and consumer acceptance has not been determined. We hypothesized that NaCl content in food may be reduced by partial replacement with fish sauce without diminishing palatability and consumer acceptance. Preparations of 3 types of food were assessed to test this hypothesis: chicken broth (n = 72); tomato sauce (n = 73); and coconut curry (n = 70). In the first session, the percentage of NaCl that could be replaced with fish sauce without a significant change in overall taste intensity was determined for each type of food using the 2‐Alternative Forced Choice method. In the second session, subjects rated 5 samples for each food with varying NaCl and/or fish sauce content on 3 sensory attributes: deliciousness; taste intensity; and saltiness. Our results demonstrate that NaCl reduction was possible in chicken broth, tomato sauce, and coconut curry at 25%, 16%, and 10%, respectively, without a significant loss (P < 0.05) in deliciousness and overall taste intensity. These results suggest that it is possible to replace NaCl in foods with fish sauce without reducing overall taste intensity and consumer acceptance.     

Safety of raw meat and shellfish in Vietnam: an analysis of Escherichia coli isolations for antibiotic resistance and virulence genes

This study was conducted to examine a current baseline profile of antimicrobial resistance and virulence of Escherichia coli isolated from foods commonly sold in the market place in Vietnam. E. coli were isolated from 180 samples of raw meat, poultry and shellfish and also isolated from 43 chicken faeces samples. Ninety-nine E. coli isolates recovered from all sources were selected for the investigation of their susceptibility to 15 antimicrobial agents by the disk diffusion method. Eighty-four percent of the isolates were resistant to one or more antibiotics, and multi-resistance, defined as resistance to at least 3 different classes of antibiotics, was detected in all sources. The rates of multi-resistance were up to 89.5% in chicken, 95% in chicken faeces and 75% in pork isolates. Resistance was most frequently observed to tetracycline (77.8%), sulfafurazole (60.6%), ampicillin (50.5%), amoxicillin (50.5%), trimethoprim (51.5%), chloramphenicol (43.4%), streptomycin (39.4%), nalidixic acid (34.3%) and gentamicin (24.2%). In addition, the isolates also displayed resistance to fluoroquinolones (ciprofloxacin 16.2%, norfloxacin 17.2%, and enrofloxacin 21.2%), with chicken isolates showing the highest rates of resistance to these antibiotics (52.6-63.2%). Thirty-eight multi-resistant isolates were selected for further the examination of antibiotic resistance genes and were also evaluated for virulence gene profiles by multiplex and uniplex polymerase chain reaction. The beta-lactam TEM gene and tetracycline resistance tetA, tetB genes were frequently detected in the tested isolates (84.2% and 89.5% respectively). Genes which are responsible for resistance to streptomycin (aadA) (68.4%), chloramphenicol (cmlA) (42.1%), sulfonamides (sulI) (39.5%), trimethoprim (dhfrV) (26.3%) and kanamycin (aphA-1) (23.7%) were also widely distributed. Plasmid-mediated ampC genes were detected in E. coli isolates from chicken and pork. The isolates were tested for the presence of 58 virulence genes for adhesins, toxins, capsule synthesis, siderophores, invasins and others from different E. coli pathotypes. All of the tested isolates contained at least one virulence gene and there were 16 genes detected. Virulence genes detected were fimH (92.1%), bmaE (84.2%), TSPE4.C2 (42.1%), aidA AIDA-I (orfB) (31.6%), east1 (26.3%), traT (23.7%), and others including fyuA, iutA, chuA, yjaA, iss, iroN(E. coli), ibeA, aah (orfA), iha and papG allele III (10.5-2.6%). Typical toxin genes produced by enterohemorrhagic and enterotoxigenic E. coli pathotypes (a heat-stable toxin (ST), heat-labile toxin (LT) and Shiga toxin stx1, stx2) were not detected in any of these 38 isolates. The study has revealed that E. coli in raw foods is a significant reservoir of resistance and virulence genes.     

A digital microfluidic droplet generator produces self-assembled supramolecular nanoparticles for targeted cell imaging

Controlling the size distribution of polymer-based nanoparticles is a challenging task due to their flexible core and surface structures. To accomplish such as task requires very precise control at the molecular level. Here we demonstrate a new approach whereby uniform-sized supramolecular nanoparticles (SNPs) can be reliably generated using a digital microfluidic droplet generator (DMDG) chip. A microfluidic environment enabled precise control over the processing parameters, and therefore high batch-to-batch reproducibility and robust production of SNPs with a very narrow size distribution could be realized. Digitally adjustment of the mixing ratios of the building blocks on the DMDG chip allowed us to rapidly scan a variety of synthesis conditions without consuming significant amounts of reagents. Nearly uniform SNPs with sizes ranging from 35 to 350?nm were obtained and characterized by transmission electron microscopy and dynamic light scattering. In addition, we could fine-tune the surface chemistry of the SNPs by incorporating an additional building block functionalized with specific ligands for targeting cells. The sizes and surface properties of these SNPs correlated strongly with their cell uptake efficiencies. This study showed a feasible method for microfluidic-assisted SNP production and provided a great means for preparing size-controlled SNPs with desired surface ligand coverage.     

High-speed two-dimensional electron-gas FET logic

Ring oscillators using planar enhancement-mode two-dimensional electron-gas FETs (TEGFETs) and ungated transistor loads are described. A propagation delay time of 19.1 ps has been measured at room temperature, the lowest yet reported for this temperature. Improvements on materials and circuit design should lead to a delay time of 10 ps at 300 K.     

The growth of silver on GaAs{001}: Epitaxial relationships,mode of growth and interfacial diffusion

In this paper we report a detailed investigation of the epitaxial growth of silver films on GaAs{001} layers prepared in situ by molecular beam epitaxy. The epitaxial relationship between silver and GaAs{001} together with the mode of metal growth and the interfacial diffusion were mainly determined by low energy electron diffraction, Auger electron spectroscopy (AES) and scanning electron microscopy. The epitaxial relationship was shown to depend markedly on the growth temperature: below 200 °C it is Ag(011)//GaAs{001} while above 200 °C it is Ag(001)//GaAs{001} The temperature of growth also plays a key role in determining the mechanism of the metal growth. The very first stages of growth (submonolayer and monolayer range) were studied using the method of Auger signal-time plots: at low temperature (about 50 °C) the growth mechanism is very close to the two-dimensional layer-by-layer type (Franck-van der Merwe mode) while three-dimensional growth begins to appear when the temperature is raised and becomes completely dominant above 400 °C, where well-defined crystallites develop. AES results are well correlated with the topology of the metal films as revealed by scanning electron microscopy. AES was also used to probe interfacial diffusion: it was found that gallium out-diffusion through the metal layer becomes significant above 400 °C.     

Etude thermochimique de la synthese en phase vapeur de Y3Fe5O12

Thermochemistry of oxidation and hydrolysis of YCl₃ and FeCl₂ have been studied. It has been shown that Y₃Fe₅O₁₂ cannot be formed by hydrolysis. Conditions of synthesis have been established in oxidation, particularly it is pointed out that excess of HCl or Cl₂ is not recommended for moderating reactions. It makes the synthesis difficult to control. Theoretical results are compared to experimental data.     

Speed power in planar two-dimensional electron gas FET DCFL circuit: a theoretical approach

A comparative study is made on the speed power of the two-dimensional electron gas FET (TEGFET) and the conventional GaAs FET. It is shown that the TEGFET is three times faster than the GaAs FET. Propagation delay times of 10 and 6 ps are predicted at 300 and 77 K, respectively, for a gate length of about 1 ?m. Effects of electron velocity and mobility are given.