Poly(ethylene oxide)-block-poly(α-cinnamyl-ε-caprolactone-co-ε-caprolactone) diblock copolymer nanocarriers for enhanced solubilization of caffeic acid phenethyl ester

We report novel micellar carriers, comprising pendant cinnamyl moieties in the core-forming block, designed to increase the solubilization of caffeic acid phenethyl ester (CAPE) in aqueous media. Amphiphilic poly(ethylene oxide)-block-poly(α-cinnamyl-ε-caprolactone-co-ε-caprolactone) (PEO-b-P(CyCL-co-CL) diblock copolymers were synthesized by ring-opening copolymerization of α-propargyl-ε-caprolactone and ε-caprolactone from a monofunctional PEO macroinitiator and subsequent attachment of cinnamyl groups via click reaction. In addition, a linear PEO-b-PCL diblock copolymer was synthesized and used in this study for comparison. Next, nanosized micelles from PEO-b-P(CyCL-co-CL) and PEO-b-PCL were formed via the solvent evaporation method and then loaded with CAPE. Dynamic and electrophoretic light scattering, and transmission electron microscopy were used to characterize both blank and loaded carriers. The potential of the micelles comprising pendant cinnamyl group to solubilize CAPE in water was evaluated in a comparative fashion to that of nonmodified PEO-b-PCL diblock copolymer.     

Global analytic and Gevrey solvability of sublaplacians under Diophantine conditions

In this paper we consider the problem of global analytic and Gevrey solvability for a class of partial differential operators on a torus in the form of squares of vector fields. We prove that global analytic and Gevrey solvability on the torus is equivalent to certain Diophantine approximation properties. Mathematics Subject Classification (2000) 35D05, 46E10, 46F05, 58J99     

Composition and antimicrobial activity of Seseli globiferum essential oil

The essential oil from aerial parts of Seseli globiferum Vis. obtained by hydrodistillation with Clevenger-type apparatus was analyzed by GC-MS. Twenty-eight compounds were identified, representing 99.4% of the total oil. The main components of the oil were sabinene (38.0%), alpha-pinene (21.2%) and beta-phellandrene (13.5%). The microbial growth inhibitory properties of the isolated essential oil were determined using the broth microdilution method against seven bacterial species: Salmonella typhimurium (ATCC 13311), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Enterobacter cloacae (clinical isolates), Bacillus cereus (clinical isolates), Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Micrococcus flavus (ATCC 10240) and three fungal species: Aspergillus niger (ATCC 6275), Aspergillus versicolor (ATCC 11730), Trichoderma viride (IAM 5061) and Penicillium funiculosum (ATCC 36839). The essential oil showed activity against bacteria P. aeruginosa, followed by M flavus, L. monocytigenes and E. coli, and all investigated fungal species.     

On the uniqueness of generalized and quasi-regular solutions to equations of mixed type in ℝ<Superscript>3</Superscript>

Some three-dimensional (3D) problems for mixed type equations of first and second kind are studied. For equation of Tricomi type, they are 3D analogs of the Darboux (or Cauchy-Goursat) plane problem. Such type problems for a class of hyperbolic and weakly hyperbolic equations as well as for some hyperbolic-elliptic equations are formulated by M. Protter in 1952. In contrast to the well-posedness of the Darboux problem in the 2D case, the new 3D problems are strongly ill-posed. A similar statement of 3D problem for Keldysh-type equations is also given. For mixed type equations of Tricomi and Keldysh type, we introduce the notion of generalized or quasi-regular solutions and find sufficient conditions for the uniqueness of such solutions to the Protter’s problems. The dependence of lower order terms is also studied.     

Linear loss networks

This paper investigates theoretical properties of throughput and cost in linear loss networks. The maximum throughput of the network with exponential service times is derived and the arrival process that maximizes throughput, given a fixed arrival rate, is established. For general service times, an asymptotically critical loading regime is identified such that the probability of an arbitrary customer being lost is strictly within (0,1) as the network size increases. This regime delivers throughput comparable to the maximum at a relatively low network cost. The paper establishes the asymptotic throughput and network cost under this critical loading.     

Multifunctional PES fabrics modified with colloidal Ag and TiO2 nanoparticles

This study is aimed to highlight the possibility of engineering the multifunctional textile nanocomposite material based on the polyester (PES) fabric modified with colloidal Ag and TiO₂ nanoparticles (NPs). The effects of concentration of NPs as well as the order of Ag and TiO₂ NPs loading on antimicrobial, UV protective, and photocatalytic properties of PES fabrics were examined. The antimicrobial activity of differently modified PES fabrics was tested against Gram‐negative bacterium Escherichia coli, Gram‐positive bacterium Staphylococcus aureus, and fungus Candida albicans. The concentration of Ag colloid and the order of Ag and TiO₂ NPs loading considerably affected the antimicrobial efficiency of PES fabrics. The fabrics provided maximum UV protection upon surface modification with Ag and TiO₂ NPs. Ag NPs enhanced Ag NPs enhanced the photodegradation activity of TiO₂ NPs and total photodegradation of methylene blue was achieved after 24 hr of UV illumination. Copyright © 2010 John Wiley & Sons, Ltd.     

Gevrey Hypoellipticity for Maximally Hypoelliptic Fourth Order Partial Differential Operators

Local C∞ and (sharp) Gevrey hypoellipticity are proved for maximally hypoelliptic fourth order partial differential operators of the form P = D|c|<4 aa(x)Xa in R" where the independent real vector fields Xj,j<n - l, satisfy the Hörmander condition that at most k brackets of the Xj spans the tangent space at each point.     

In situ Spectroscopic Insight into the Origin of the Enhanced Performance of Bimetallic Nanocatalysts towards the Oxygen Reduction Reaction (ORR)

It is vital to understand the oxygen reduction reaction (ORR) mechanism at the molecular level for the rational design and synthesis of high activity fuel‐cell catalysts. Surface enhanced Raman spectroscopy (SERS) is a powerful technique capable of detecting the bond vibrations of surface species in the low wavenumber range, however, using it to probe practical nanocatalysts remains extremely challenging. Herein, shell‐isolated nanoparticle‐enhanced Raman spectroscopy (SHINERS) was used to investigate ORR processes on the surface of bimetallic Pt₃Co nanocatalyst structures. Direct spectroscopic evidence of *OOH suggests that ORR undergoes an associative mechanism on Pt₃Co in both acidic and basic environments. Density functional theory (DFT) calculations show that the weak *O adsorption arise from electronic effect on the Pt₃Co surface accounts for enhanced ORR activity. This work shows SHINERS is a promising technique for the real‐time observation of catalytic processes.