Nanostructures increase water droplet adhesion on hierarchically rough superhydrophobic surfaces

Hierarchical roughness is known to effectively reduce the liquid-solid contact area and water droplet adhesion on superhydrophobic surfaces, which can be seen for example in the combination of submicrometer and micrometer scale structures on the lotus leaf. The submicrometer scale fine structures, which are often referred to as nanostructures in the literature, have an important role in the phenomenon of superhydrophobicity and low water droplet adhesion. Although the fine structures are generally termed as nanostructures, their actual dimensions are often at the submicrometer scale of hundreds of nanometers. Here we demonstrate that small nanometric structures can have very different effect on surface wetting compared to the large submicrometer scale structures. Hierarchically rough superhydrophobic TiO(2) nanoparticle surfaces generated by the liquid flame spray (LFS) on board and paper substrates revealed that the nanoscale surface structures have the opposite effect on the droplet adhesion compared to the larger submicrometer and micrometer scale structures. Variation in the hierarchical structure of the nanoparticle surfaces contributed to varying droplet adhesion between the high- and low-adhesive superhydrophobic states. Nanoscale structures did not contribute to superhydrophobicity, and there was no evidence of the formation of the liquid-solid-air composite interface around the nanostructures. Therefore, larger submicrometer and micrometer scale structures were needed to decrease the liquid-solid contact area and to cause the superhydrophobicity. Our study suggests that a drastic wetting transition occurs on superhydrophobic surfaces at the nanometre scale; i.e., the transition between the Cassie-Baxter and Wenzel wetting states will occur as the liquid-solid-air composite interface collapses around nanoscale structures. Consequently, water adheres tightly to the surface by penetrating into the nanostructure. The droplet adhesion mechanism presented in this paper gives valuable insight into a phenomenon of simultaneous superhydrophobicity and high water droplet adhesion and contributes to a more detailed comprehension of superhydrophobicity overall.     

Excitation energy transfer in isolated chlorosomes from Chlorobaculum tepidum and Prosthecochloris aestuarii

Excitation energy transfer in chlorosomes from photosynthetic green sulfur bacteria, Chlorobaculum (Cba.) tepidum and Prosthecochloris (Pst.) aestuarii, have been studied at room temperature by time-resolved femtosecond transient absorption spectroscopy. Bleach rise times from 117 to 270 fs resolved for both chlorosomes reflect extremely efficient intrachlorosomal energy transfer. Bleach relaxation times, from 1 to 3 ps and 25 to 35 ps, probed at 758 nm were tentatively assigned to intrachlorosomal energy transfer based on amplitude changes of the global fits and model calculations. The anisotropy decay constant of about 1 ps resolved at 807 nm probe wavelength for the chlorosomes from Chloroflexus aurantiacus, Pst. aestuarii and Cba. tepidum was related to energy transfer between bacteriochlorophyll a molecules of the baseplate and partly to intrachlorosomal energy transfer. The longer anisotropy components 6.6, 8.8 and 12.1 ps resolved for the three chlorosomes, respectively, were assigned to chlorosome to baseplate energy transfer. Global fits of magic-angle data also revealed longer chlorosome to baseplate energy transfer components from 95 to 135 ps, in accord with results from simulations.     

Temporal networks

A great variety of systems in nature, society and technology–from the web of sexual contacts to the Internet, from the nervous system to power grids–can be modeled as graphs of vertices coupled by edges. The network structure, describing how the graph is wired, helps us understand, predict and optimize the behavior of dynamical systems. In many cases, however, the edges are not continuously active. As an example, in networks of communication via e-mail, text messages, or phone calls, edges represent sequences of instantaneous or practically instantaneous contacts. In some cases, edges are active for non-negligible periods of time: e.g., the proximity patterns of inpatients at hospitals can be represented by a graph where an edge between two individuals is on throughout the time they are at the same ward. Like network topology, the temporal structure of edge activations can affect dynamics of systems interacting through the network, from disease contagion on the network of patients to information diffusion over an e-mail network. In this review, we present the emergent field of temporal networks, and discuss methods for analyzing topological and temporal structure and models for elucidating their relation to the behavior of dynamical systems. In the light of traditional network theory, one can see this framework as moving the information of when things happen from the dynamical system on the network, to the network itself. Since fundamental properties, such as the transitivity of edges, do not necessarily hold in temporal networks, many of these methods need to be quite different from those for static networks. The study of temporal networks is very interdisciplinary in nature. Reflecting this, even the object of study has many names—temporal graphs, evolving graphs, time-varying graphs, time-aggregated graphs, time-stamped graphs, dynamic networks, dynamic graphs, dynamical graphs, and so on. This review covers different fields where temporal graphs are considered, but does not attempt to unify related terminology—rather, we want to make papers readable across disciplines.     

Coherent-mode representation of supercontinuum

We apply the coherent-mode expansion to correlation functions used to describe the coherence properties of supercontinuum generated in nonlinear ?bers. We show that the leading term of the expansion represents the quasi-coherent part of the ?eld while the quasi-stationary part is embedded into the higher-order modes. The evolution of the modal expansion and the number of modes needed to describe the supercontinuum ?eld are also discussed.     

Maximal spanning trees,asset graphs and random matrix denoising in the analysis of dynamics of financial networks

We study the time dependence of maximal spanning trees and asset graphs based on correlation matrices of stock returns. In these networks the nodes represent companies and links are related to the correlation coefficients between them. Special emphasis is given to the comparison between ordinary and denoised correlation matrices. The analysis of single- and multi-step survival ratios of the corresponding networks reveals that the ordinary correlation matrices are more stable in time than the denoised ones. Our study also shows that some information about the cluster structure of the companies is lost in the denoising procedure. Cluster structure that makes sense from an economic point of view exists, and can easily be observed in networks based on denoised correlation matrices. However, this structure is somewhat clearer in the networks based on ordinary correlation matrices. Some technical aspects, such as the random matrix denoising procedure, are also presented.     

Search for Higgs bosons in SUSY cascades in CMS and dark matter with non-universal gaugino masses

In grand-unified theories (GUT), non-universal boundary conditions for the gaugino masses may arise at the unification scale and may affect the observability of the neutral MSSM Higgs bosons (h/H/A) at the LHC. The implications of such non-universal gaugino masses are investigated for Higgs boson production in the SUSY cascade decay chain , , , produced in pp interactions. In the singlet representation with universal gaugino masses only the light Higgs boson can be produced in this cascade with the parameter region of interest for us, while with non-universal gaugino masses heavy neutral MSSM Higgs boson production may dominate. The allowed parameter space in the light of the WMAP constraints on the cold dark-matter relic density is investigated in the above scenarios for gaugino mass parameters. We also demonstrate that combination of representations can give the required amount of dark matter in any point of the parameter space. In the non-universal case we show that heavy Higgs bosons can be detected in the cascade studied in parameter regions with the WMAP preferred neutralino relic density.     

Linearization of holomorphic mappings onC(K)-spaces

We prove a universal mapping theorem for “integral” holomorphic mappings on the open unit ball ofC(K). In our theorem, the universal space isC(K), and the universal mapping is increasing in the positive cone ofC(K).     

Analysis of volatile sesquiterpenoids in environmental and geological samples

In order to evaluate vloatile compounds, especiallly sesquiter-penoids, in environmental and geological samples a method was penoids, in environmental and geological samples a method was required to characterize these components when they occur at low concentrations. After fractionation of the total sample extracts by TLC the aliphatic fractions were analyzed by HRGC AND THE kovats indices of all resolved peaks were calculated and comkpared with indices of all resolved peaks were calculated and compared with those obtained for commercial standards. As final step, the fractions were analyzed by HRGC-MS and structures confirmed by comparison of their mass spectra with those of certified sesuiterpene standards. Additionally sesquiterpenoids present in the dissolved phase in water samples were concentrated by solid phase extraction using XAD-2 resin. In this initial study, recovery tests with the resin were carried out in order to evaluate its performance rather than validating the methodology.     

High temperature gas chromatography on narrow bore capillary columns

The use of high-temperature-stable, medium polarity glass capillary columns coated with immobilized PS-090 (a 20 % diphenyl-substituted, CH₃O-terminated polydimethylsiloxane) has made it possible to analyze routinely, and with good separation efficiency, high molecular weight compounds such as triglycerides and free base porphyrins. Cold on-column injection was used throughout this work to avoid discrimination against involatile compounds, and disposable (fused silica) retention gaps were used to protect the column against contamination with involatile material. On-column injection into narrow bore glass columns was achieved by using glass-to-silica connections to attach wider bore (0.2 mm i.d.) deactivated fused silica tubing to the columns.     

Analysis of small molecules by ultra thin-layer chromatography-atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry

The feasibility of ultra thin-layer chromatography atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry (UTLC-AP-MALDI-MS) has been studied in the analysis of small molecules. Because of a thinner adsorbent layer, the monolithic UTLC plates provide 10-100 times better sensitivity in MALDI analysis than conventional high performance thin-layer chromatography (HPTLC) plates. The limits of detection down to a low picomole range are demonstrated by UTLC-AP-MALDI-MS. Other advantages of UTLC over HPTLC include faster separations and lower solvent consumption. The performances of AP-MALDI-MS and vacuum MALDI-MS have been compared in the analysis of small drug molecules directly from the UTLC plates. The desorption from the irregular surface of UTLC plates with an external AP-MALDI ion source combined with an ion trap instrument provides clearly less variation in measurements of m/z values when compared with a vacuum MALDI-time-of-flight (TOF) instrument. The performance of the UTLC-AP-MALDI-MS method has been applied successfully to the purity analysis of synthesis products produced by solid-phase parallel synthesis method.