Aggregation-based fabrication and assembly of roughened composite metallic nanoshells: Application in surface-enhanced Raman scattering

This paper reports an aggregation-based method for the fabrication of composite Au/Ag nanoshells with tunable thickness and surface roughness. It is found that the resultant roughened composite Au/Ag nanoshells can attract each other spontaneously to form films at the air-water interface. Importantly, such films can be transferred onto the solid substrates without being destroyed and show excellent surface-enhanced Raman scattering (SERS) enhancement ability. Their strong enhancement ability may stem from the unique two-dimensional structure itself.

Nanometer scale mechanical study on well defined nanostructured chain aggregation of polyethylene

Two kinds of polyethylene chain aggregation with chain axis perpendicular and parallel to the supported substrate were designed and successfully obtained from melt under an electric field and by melt-drawn method

Aggregation behavior of amphiphilic D-pi-A molecules bearing recognition group

Aggregation behavior of two amphiphilic D-pi -A molecules bearing barbituric acid as both recogniton group and electron-drawing substituent, 5-(4-dodecyl oxybenzylidene)-(1H, 3H)-2,4,6-pyrimidine trione (PB12) and 5-(4-N,N-didodecyl aminobenzylidene)-(1H,3H)-2,4,6-pyrimidine trione (AB(12)) was studied by UV-visible, fluorescence, and surface voltaic spectroscopies (SPS). The experimental results indicate that PB12 tends to form J-aggregate and AB(12) tends to form H-aggregate under increasing concentration. An intramolecular twisted charge transfer (TICT) emission around 500 nm is observed when J-aggregate is formed between PB12 molecules, and an excimer emission around 600 nm is observed when H-aggregate is formed between AB(12) molecules.

Tuning the aggregation of polyimide thin films by modification of their molecular interactions

Thin films of an organo-soluble polyimide based on 1,4-(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) and 2,2'-dimethyl-4,4'-methylene dianiline (DMMDA) have been studied. A prism coupler was used to measure the refractive indices. The average refractive indices of thin films prepared by annealing at different temperatures and times were chosen to characterize the condensation states of thin films. Thin films annealed at 200 degrees C show irreversible changes in physical properties, eg solubility. FTIR spectroscopy showed that the chain structures of the above thin films remained unchanged. It is proposed that specific molecular interactions induce the irreversible changes revealed by fluorescence spectroscopy. (C) 2000 Society of Chemical Industry.

Fluorescence and aggregation behavior of a polyimide in solutions

The UV-visible absorption and fluorescence spectra of a soluble polyimide, YS-30, in several organic solvents were measured over a wide range of concentration. The experimental results show that there exist both intramolecular and intermolecular electron donor acceptor interactions for YS-30 molecules. The fluorescence behavior of YS-30 in N,N-dimethylacetamide and in chloroform solutions is similar in general, except that its ground-state intermolecular charge transfer emission is more obvious in N,N-dimethylacetamide solution. This difference is attributed to the greater extent of disruption of the chain packing by solvent or/and the more efficient radiationless energy dissipation process from the excited state complexes to chloroform. The intensity ratio of intermolecular charge transfer emission to intramolecular charge transfer emission is used to characterize the state of aggregation of YS-30 molecules in solutions. The plot of this ratio versus concentration indicates the existence of two critical concentrations. It is also found from the same plot that the decrease of coil size is very pronounced during the initial stage of shrinkage.

Synchronous fluorescence spectra of hemoglobin: A study of aggregation states in aqueous solutions

The synchronous fluorescence spectra of hemoglobin solutions are reported for the first rime. The main fluorescence peaks observed in the spectra are assigned. The effect of the concentration of hemoglobin solution on the spectra is studied. Characteristic fluorescence peaks due to the dimer and tetramer of hemoglobin molecules are recognized. (C) 1998 Academic Press.

The aggregation state of polyimide

The aggregation slate of polyimide in solution and in the solid state were studied using the NMR and fluorescence techniques. The experiment results show that the decay of spin-spin relaxation of polyimides with concentration can be described as a single exponential, biexponential, triexponential, biexponential profile. Meanwhile, the intensities of fluorencence spectra increase rapidly with the concentration, and some peaks have a red-shift. Based upon these experiment results, it can be concluded that polyimide in solution is very flexible, and there are several critical concentrations at which polyimide has distinctly different aggregation states. The existence of intermolecular charge transfer interaction between polyimide chains has been proved, and the interaction has a profound effect on the glass transition temperature, T-g, and the dynamic mechanical modulus of polyimide. (C) 1997 Elsevier Science Ltd.

Inhibitory effects and mechanisms of high molecular-weight phlorotannins from Sargassum thunbergii on ADP-induced platelet aggregation

We evaluated the effects of high molecular-weight phlorotannins from Sargassum thunbergii (STP) on ADP-induced platelet aggregation and arachidonic acid (AA) metabolism in New Zealand white rabbits and Wistar rats. The inhibition of STP on platelet aggregation was investigated using a turbidimetric method, and the levels of the terminal products of AA metabolism were measured using the corresponding kits for maleic dialdehyde (MDA), thromboxane B-2 (TXB2) and 6-keto-prostaglandin F-1 alpha (6-keto-PGF(1 alpha)) by colorimetry and radioimmunoassay, as appropriate. We found that STP could inhibit ADP-induced platelet aggregation, and the inhibitory ratio was 91.50% at the STP concentration of 4.0 mg/mL. Furthermore, STP markedly affected AA metabolism by decreasing the synthesis of MDA (P < 0.01) and increasing the synthesis of 6-keto-PGF(1 alpha), thus changing the plasma TXB2/6-keto-PGF(1 alpha) balance when the platelets were activated (P < 0.01). Therefore, STP altered AA metabolism and these findings

Influence of albumen on aggregation and O-2 evolution of protoplasm from Bryopsis hypnoides Lamourou

The extruded protoplasm from the coenocytic green alga, Bryopsis hypnoides Lamouroux, was able to reform a cell wall and develop further into a mature alga in seawater. In this paper, the influence of albumen on the ability of aggregation and on the photosynthesis of protoplasm was examined. Results show that the protoplasm of B. hypnoides could aggregate in either albumen or chicken egg, which is similar to that in seawater. However unlike in seawater, the aggregation from B. hypnoides in albumen and chicken egg failed to develop into a mature individual. Interestingly, the protoplasm of B. hypnoides could maintain its photosynthetic O-2 evolution in albumen and chicken egg, while the time in chicken egg was longer than that in albumen.

Semi-Supervised OWA Aggregation for Link-Based Similarity Evaluation and Alias Detection

T.Boongoen and Q. Shen. Semi-Supervised OWA Aggregation for Link-Based Similarity Evaluation and Alias Detection. Proceedings of the 18th International Conference on Fuzzy Systems (FUZZ-IEEE'09), pp. 288-293, 2009. Sponsorship: EPSRC

Habit, aggregation and long memory: Evidence from television audience data

Byers, D., Peel, D., Thomas, D. (2007). Habit, aggregation and long memory: Evidence from television audience data. Applied Economics, 39 (3), 321-327. RAE2008

Handedness and social anxiety: using Bryden's research as a catalyst to explore the influence of familial sinistrality and degree of handedness

Phil Bryden's work has impacted on many areas of laterality, including degree and measurement of hand preference, as well as influences of familial sinistrality (FS). For example, Bryden[(1977). Measuring handedness with questionnaires. Neuropsychologia, 15, 617–624] is a well-cited and influential paper that remains relevant to this day. Inspired by this we extended our analysis of the relationship between handedness and anxiety in a number of ways. We used familial handedness and strength of handedness to examine their potential influences on anxiety, and extended our research by exploring their relationship to social anxiety, using the Social Phobia Inventory (SPIN). Inconsistent left-handers (ILH) were found to be more socially anxious. In all categories of SPIN except avoidance, ILH were significantly more anxious than consistent right- and left-handers. There were FS differences between ILH with a first degree left-handed relative (FS+) compared to ILH with no first degree left-handed relative (FS−) on all categories of anxiety scores. Within FS+ participants, ILH had significantly higher anxiety scores, compared with consistent handers across all categories. This suggests that ILH's social anxiety may be influenced by a close left-handed relative. Inspired by examining Bryden's work for this special issue, we will continue to add both strength of preference and familial handedness to our work.

Non-anonymous ballot aggregation: an axiomatic generalization of Approval Voting

We study axiomatically situations in which the society agrees to treat voters with different characteristics distinctly. In this setting, we propose a set of intuitive axioms and show that they jointly characterize a new class of voting procedures, called Type-weighted Approval Voting. According to this family, each voter has a strictly positive and finite weight (the weight is necessarily the same for all voters with the same characteristics) and the alternative with the highest number of weighted votes is elected. The implemented voting procedure reduces to Approval Voting in case all voters are identical or the procedure assigns the same weight to all types. Using this idea, we also obtain a new characterization of Approval Voting.

On the Interaction between Data Aggregation and Topology Control in Wireless Sensor Networks

Wireless sensor networks are characterized by limited energy resources. To conserve energy, application-specific aggregation (fusion) of data reports from multiple sensors can be beneficial in reducing the amount of data flowing over the network. Furthermore, controlling the topology by scheduling the activity of nodes between active and sleep modes has often been used to uniformly distribute the energy consumption among all nodes by de-synchronizing their activities. We present an integrated analytical model to study the joint performance of in-network aggregation and topology control. We define performance metrics that capture the tradeoffs among delay, energy, and fidelity of the aggregation. Our results indicate that to achieve high fidelity levels under medium to high event reporting load, shorter and fatter aggregation/routing trees (toward the sink) offer the best delay-energy tradeoff as long as topology control is well coordinated with routing.