Mobile anchor-assisted localization over android

While localization is essential to many applications, there are quantities of wireless nodes whose accurate locations remain unknown or hard to tell. As a remedy, this paper is leveraging a GPS-capable Android handset that features portability and sufficient computing capability to collect data and display localization results thereof. Our objective is to locate the unknown nodes under irregular radio coverage. To this end, we first devise a range-free approach that computes the most likely circumcenter from a convex polygon representative of radio coverage. Preliminary simulations corroborate the effectiveness of our development. Then the first approach is simplified by allowing for received signal strengths with the notion of estimative regions, namely rectangular areas enclosing an unknown node, to refine the area of interest for localization. Free from involved computations, our treatment mitigates the errors of estimation resulting from different radio signal propagation scenarios, by taking an additional parameter for ameliorating localization accuracy. Field experiments were conducted to demonstrate performance results overlying Google Maps on the handset and through quantitative comparisons in different settings. Performance results show that our development can get fielded in practice.     

MUC1 Aptamer Targeted SERS Nanoprobes

Recently, surface‐enhanced Raman scattering (SERS) nanoprobes (NPs) have shown promise in the field of cancer imaging due to their unparalleled signal specificity and high sensitivity. This study reports the development of a DNA aptamer targeted SERS NP. Recently, aptamers are being investigated as a viable alternative to more traditional antibody targeting due to their low immunogenicity and low cost of production. A strategy is developed to functionalize SERS NPs with DNA aptamers, which target Mucin1 (MUC1) in human breast cancer (BC). Thorough in vitro characterization studies demonstrate excellent serum stability and specific binding of the targeted NPs to MUC1. In order to test their in vivo targeting capability, MUC1‐targeted SERS NPs are coinjected with nontargeted or blocked MUC1‐targeted SERS NPs in BC xenograft mouse models. A two‐tumor mouse model with differential expression of MUC1 (MDA‐MB‐468 and MDA‐MB‐453) is used to control for active versus passive targeting in the same animals. The results show that the targeted SERS NPs home to the tumors via active targeting of MUC1, with low levels of passive targeting. This strategy is expected to be an advantageous alternative to antibody‐based targeting and useful for targeted imaging of tumor extent, progression, and therapeutic response.     

A quadrature method for a class of strongly oscillatory infinite integrals

A constructive process is presented which leads to a class of quadrature formulas with any preassigned compound precision for the numerical integration of rapidly oscillating functions on (0, ) of the forme ^–x F(x, x), where is a large parameter andF(·,y) is periodic of period unity iny.1980 Mathematics Subject Classification, Primary 41A55, Scondary 41A60     

Structural studies on ceramides as lithiated adducts by low energy collisional-activated dissociation tandem mass spectrometry with electrospray ionization

We applied electrospray ionization (ESI) tandem quadrupole mass spectrometry to establish the fragmentation pathways of ceramides under low energy collisional-activated dissociation (CAD) by studying more than thirty compounds in nine subclasses. The product-ion spectra of the [M + Li]+ ions of ceramides contain abundant fragment ions that identify the fatty acyl substituent and the long-chain base (LCB) of the molecules, and thus, the structure of ceramides can be easily determined. Fragment ions specific to each ceramide subclasses are also observed. These feature ions permit differentiation among different ceramide subclasses. The ion series arising from the classical C-C bond cleavages that were reported in the fast-atom bombardment (FAB)-high energy tandem mass spectrometry is not observable; however, the product-ion spectra contain multiple fragment ions informative for structural characterization and isomer identification. We also investigated the tandem mass spectra of the fragment ions generated by in-source CAD (pseudo-MS3) and of the deuterium-labeling molecular species obtained by H/D exchange to support the ion structure assignments and the proposed fragmentation pathways that lead to the ion formation.     

Synthesis and reactivity of the hydrido- and alkylrhenium methylidene complexes Cp*(PMe3)2(R)Re=CH2 (R = H, CH3)

Protonolysis of the dimethylrhenium(III) compound Cp(PMe(3))(2)Re(CH(3))(2) (3) led to formation of the highly reactive hydridorhenium methylidene compound [Cp(PMe(3))(2)Re(CH(2))(H)][OTf] (4), which was characterized spectroscopically at low temperature. Although 4 decomposed above -30 degrees C, reactivity studies performed at low temperature indicated it was in equilibrium with the coordinatively unsaturated methylrhenium complex [Cp(PMe(3))(2)Re(CH(3))][OTf] (2). Methylidene complex 4 was found to react with PMe(3) to afford [Cp(PMe(3))(3)Re(CH(3))][OTf] (6) and with chloride anion to give Cp(PMe(3))(2)Re(Me)Cl (7). When BAr(f) anion was added to 4, the thermally stable methylrhenium methylidene complex [Cp(PMe(3))(2)Re(CH(2))(CH(3))][BAr(f)] (8) was isolated upon warming to room temperature. The mechanisms of formation of both 4 and 8 are discussed in detail, including DFT calculations. The novel carbonyl ligated complex Cp(CO)(2)Re(CH(3))OTf (12) was prepared, isolated, and found to not undergo migration reactions to form methylidene complexes.     

Polymer supported catalyst for the effective autoxidation of cumene to cumene hydroperoxide

The autoxidation of cumene to cumene hydroperoxide (CHP) in the presence of catalyst which was prepared by adsorbing copper(II) acetate onto polymer support, was investigated. When a styrene-divinylbenzene copolymer with sulfonic acid functional groups was used as a support, the resulting catalyst had no catalytic activity. When a macroreticular acrylic polymer containing carboxylic acid exchange groups was used as a support, an effective catalyst was obtained. In the presence of this catalyst (0.2 g Cu(OAc)₂-BR-0.6 per 10 mL of cumene) at 353 K, the steady autoxidation rate is 84% faster than that initiated with CHP; the selectivity is 99% at 6.8% conversion. The catalyst is stable at 383 K. Furthermore, the catalyzed cumene autoxidation rate increases linearly with copper acetate loading as well as the amount of catalyst. But when the steady autoxidation rate increases, the selectivity to cumene hydroperoxide reduces, but is still satisfactory. Hence, it is possible to speed up the cumene autoxidation rate by raising the reaction temperature, using catalysts with high metal loading and using more catalyst.     

The Effects of Various Alcohols on the Stability of Melittin: A Molecular Dynamics Study

In this study, 200 ps molecular dynamics simulations were conducted to investigate the effects of various alcohols on the structural stability of melittin. The averaged helicity of melittin remained 80% in pure butanol, whereas it was below 60% both in pure water and in pure methanol. The α‐helix propensity of melittin increased with the aliphatic chain length of the alcohol. Charge‐charge interaction between Lys21 and Arg24 and polar‐nonpolar interaction between Trp19 and Arg22 are probably responsible for the higher structural integrity of the C‐terminal α‐helix over the N‐terminal one. The weaker dielectric constant of longer aliphatic chain length of alcohol possibly reduces the hydrogen bonding between amide protons and surrounding solvent molecules and simultaneously promotes the intramolecular hydrogen bonding in melittin and therefore stabilizes the secondary structure of melittin. The effect of various alcohols on stabilizing melittin is most likely due to their ability to form clusters on the surface of melittin effectively, favoring the formation of intramolecular hydrogen bonds instead of intermolecular hydrogen bonds and promoting the formation of stable α‐helices.     

Highly active and reusable heterogeneous catalysts for acylation of anisole

In the present study, non-conventional solid acid catalysts such as NaY, metal ion exchanged zeolite NaY (Zn²⁺, Fe³⁺, Ce³⁺, La³⁺ and Nd³⁺), H-mordenite, H-β and HZSM-5 were used in order to overcome the disadvantages of conventional Friedel-Crafts catalysts for the acylation of anisole with acetic anhydride. Among the various zeolites studied, the HY zeolite shows an intermediate activity. Zeolite containing transition metal ions (Zn²⁺ and Fe³⁺) are less active and zeolite NaY is nearly inactive. The catalysts exhibit the activity in the order H-β>transition metal ions (Zn²⁺ and Fe³⁺)>HY>NaY zeolite. The highest catalytic activity of H-β could be due to its larger pore size. The type of acidity and the acid strength in zeolite Y were determined by FTIR and differential scanning calorimetric (DSC) studies on the pyridine adsorbed catalysts. The correlation of catalytic activity with acidity reveals that Brönsted acid sites in zeolite promote the acylation of anisole.     

A Study of S(3P2,1,0; 1D2; 1S0) Production in the 193 nm Photodissociation of CH3SH

The dynamics of S(³P_2,1,0; ¹D₂; ¹S₀) production from the 193 nm photodissociation of CH₃SH has been examined by 2+1 resonance-enhanced-multiphoton-ionization (REMPI) techniques. Using the rate equation scheme, we have rationalized the intensities of S(³P_2,1,0; ¹D₂; ¹S₀) observed according to the sequential two-photon dissociative pathways, (A): CH₃SH + hv (193 nm) → CH₃S + hv (193 nm) → S and (B): CH₃SH + hv (193 nm) → HS + hv (193 nm) → S, as the major mechanisms for S production. We have satisfactorily fitted the photodissociation laser power dependencies for S(³P) and S(¹D) produced from CH₃SH by invoking photodissociation cross sections and branching ratios S(³P)/S(¹D) for CH₃S and HS similar to those determined previously in the 193 nm photodissociation of CH₃SCH₃ and H₂S. This observation supports that the 193 nm photodissociation of CH₃S and HS prepared from CH₃SH yield predominantly S(^lD) and S(³P), similar to the cases for CH₃S prepared from CH₃SCH₃ and for HS prepared from H₂S, respectively. A small amount of S(¹S₀) observed from the 193 nm photodissociation of CH₃SH is attributed to pathway (B).