Effect of dopant concentration and particle size on fluorescence properties of Y2O3:Eu3+ derived in presence of NIPAM/AAc copolymer

Y₂O₃:Eu³⁺ nano phosphors (about 65 nm in size) were prepared via co-precipitation method by using co-polymer NIPAM/AAc as a template with narrow size distribution. The aim of the paper is to indicate the co-polymer influence on size and luminescence characteristics of nano phosphors. In this respect, phase content and morphology were characterized by X-ray diffraction and transmission electron microscopy. All the powders were well crystallized and the particles were clearly spherical with good dispersibility. Luminescence measurements were used to investigate the role of precursor in powders and the utmost luminescence intensity was observed at 4 mol% of Eu³⁺ while the quenching concentration of Eu³⁺ ions has occurred at 5 mol%.     

A New Strategy for the Aminolysis of Epoxides with Amines Under Solventfree Conditions Using Fe-Mcm-41 as a Novel and Efficient Catalyst

A highly efficient method for the aminolysis of epoxides in the presence of a catalytic amount of Fe-MCM-41 is reported. An important advantage of this catalyst is the ease of separating it from the reaction mixture, as well as the fact that it could be recycled a number of times.     

A glutamic Acid-producing lactic Acid bacteria isolated from malaysian fermented foods

l-glutamaic acid is the principal excitatory neurotransmitter in the brain and an important intermediate in metabolism. In the present study, lactic acid bacteria (218) were isolated from six different fermented foods as potent sources of glutamic acid producers. The presumptive bacteria were tested for their ability to synthesize glutamic acid. Out of the 35 strains showing this capability, strain MNZ was determined as the highest glutamic-acid producer. Identification tests including 16S rRNA gene sequencing and sugar assimilation ability identified the strain MNZ as Lactobacillus plantarum. The characteristics of this microorganism related to its glutamic acid-producing ability, growth rate, glucose consumption and pH profile were studied. Results revealed that glutamic acid was formed inside the cell and excreted into the extracellular medium. Glutamic acid production was found to be growth-associated and glucose significantly enhanced glutamic acid production (1.032 mmol/L) compared to other carbon sources. A concentration of 0.7% ammonium nitrate as a nitrogen source effectively enhanced glutamic acid production. To the best of our knowledge this is the first report of glutamic acid production by lactic acid bacteria. The results of this study can be further applied for developing functional foods enriched in glutamic acid and subsequently γ-amino butyric acid (GABA) as a bioactive compound.     

Manganese chloride tetrahydrate (CMC-001) enhanced liver MRI: evaluation of efficacy and safety in healthy volunteers

Object

To evaluate the efficacy of three dose levels of the oral hepatobiliary manganese-based magnetic resonance imaging (MRI) contrast agent CMC-001, and assess its safety profile and patient acceptability.

Materials and methods

After ethics committee approval, 32 healthy volunteers (males/females: 18/14) were included. Liver MRI was performed before and 3?h after ingestion of 0.8, 0.4, and 0.2?g of CMC-001 on separate occasions. Liver-to-muscle signal intensity (SI) ratio from baseline to post-contrast and image quality was assessed. Adverse drug reactions/adverse events (ADRs/AEs) and clinico-laboratory tests were monitored.

Results

The increase in liver-to-muscle SI ratio was significantly higher after 0.8?g (0.696) compared to 0.4?g (0.458) and 0.2?g (0.223) (in all pair-wise comparisons, P?Conclusion Liver MRI using 0.8?g CMC-001 has the highest efficacy and still acceptable ADRs and should therefore be preferred.     

Preparation of Polydopamine Sulfamic Acid-Functionalized Silica Gel as Heterogeneous and Recyclable Nanocatalyst for Acetylation of Alcohols and Amines Under Solvent-Free Conditions

To fabricate SiO₂/PDA–SO₃H nanocatalyst, a suitable method is designed for the loading of sulfonic acid groups on the surface of polydopamine (PDA)-encapsulated SiO₂ nanoparticles. To bridge the gap between heterogeneous and homogeneous catalysis, surface functionalization of silica gel is an elegant procedure. The morphology, structure, and physicochemical features were specified using different analytical techniques including field emission scanning electron microscopy (FESEM), Fourier transformed infrared spectroscopy (FT-IR), high resolution-transmission electron microscopy (HR-TEM), energy dispersive X-ray spectroscopy (EDS), wavelength-dispersive X-ray spectroscopy (WDX), X-ray photoelectron spectroscopy (XPS), and back titration. The SiO₂/PDA–SO₃H nanoparticles are efficient nanocatalysts for the acetylation of many alcohols, phenols, and amines with acetic anhydride under solvent-free conditions in good to excellent yields. Moreover, the reuse and recovery of the catalyst was shown seven times without detectible loss in activity.

Graphical Abstract

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The effect of heat pretreatment temperature on fermentative hydrogen production using mixed cultures

The effect of heat treatment at different temperatures on two types of inocula, activated sludge and anaerobically digested sludge, was investigated in batch cultures. Heat treatments were conducted at 65, 80 and 95 °C for 30 min. The untreated inocula produced less amount of hydrogen than the pretreated inocula, with lactic acid as the main metabolite. The maximum yields of 2.3 and 1.6 mol H₂/mol glucose were achieved for the 65 °C pretreated anaerobically digested and activated sludges, respectively. Approximately a 15% decrease in yield was observed with increasing pretreatment temperature from 65 to 95 °C concomitant with an increase in butyrate/acetate ratio from 1.5 to 2.4 for anaerobically digested sludge. The increase of pretreatment temperature of activated sludge to 95 °C suppressed the hydrogen production by lactic acid fermentation. DNA analysis of the microbial community showed that the elevated pretreatment temperatures reduced the species diversity.     

Interprovider IP-MPLS services: requirements, implementations, and challenges

With the worldwide success of IP-MPLS [E. Rosen et al., Jan. 2001] networks deployment, inter-connecting multiple provider IP-MPLS networks for global reachability becomes the next important step. Many providers have implemented MPLS interprovider connections. In this article we first briefly describe the drivers behind the need of interprovider IP-MPLS services, such as layer 3 VPNs [E. Rosen and Y. Rekhter, Oct 2004], pseudowire emulation for transporting layer 2 traffic over IP-MPLS, VoIP, and others. We then discuss the general requirements for the interconnections, from end users' and service providers' perspectives, including security, scalability, manageability, QoS, and end-to-end SLAs. We then address the deployment options and challenges faced by service providers. Specifically, we discuss the following areas of interprovider service implementation: protocol implementation options for L3 VPN and their trade-offs, methods for guaranteeing consistent QoS across providers' boundaries, interprovider traffic engineering approaches, and operation challenges: from business to processes, from troubleshooting/monitoring to SLAs. By identifying the issues and challenges, our ultimate goal is to move toward the development of much needed common practices and procedures to assist in the establishment of interprovider IP-MPLS services.