A New Numerical Method for Accurate Simulation of Fast Cyclic Adsorption Processes

In the simulation of fast cyclic adsorption processes, to apply the Fickian diffusion model it is necessary to include an increasing number of numerical discretization points as the cycle time is reduced in comparison to the characteristic diffusional time constant. We propose a new numerical method based on the definition of two distinct regions within an adsorbent particle: an outer layer where the concentration varies significantly with large internal gradients leading to enhanced mass fluxes, and an internal region where the concentration profile is virtually flat. The proposed method leads to the automated generation of a numerical grid that has a constant number of elements independent of the process cycle time. The procedure is demonstrated on a model for the simulation of a heatless dryer pressure swing adsorption process.     

Excitation-energy migration in self-assembled cyclic zinc(II)-porphyrin arrays: a close mimicry of a natural light-harvesting system

The excitation-energy-hopping (EEH) times within two-dimensional cyclic zinc(II)-porphyrin arrays 5 and 6, which were prepared by intermolecular coordination and ring-closing metathesis reaction of olefins, were deduced by modeling the EEH process based on the anisotropy depolarization as well as the exciton-exciton annihilation dynamics. Assuming the number of energy-hopping sites N = 5 and 6, the two different experimental observables, that is, anisotropy depolarization and exciton-excition annihilation times, consistently give the EEH times of 8.0 +/- 0.5 and 5.3 +/- 0.6 ps through the 1,3-phenylene linkages of 5 and 6, respectively. Accordingly, the self-assembled cyclic porphyrin arrays have proven to be well-defined two-dimensional models for natural light-harvesting complexes.     

A rapid polyol combustion strategy towards scalable synthesis of nanostructured LiFePO4/C cathodes for Li-ion batteries

In the present study, carbon-coated lithium iron phosphate (LiFePO₄/C) is prepared directly by a polyol-assisted pyro-synthesis performed under reaction times of a few seconds in open-air conditions. The polyol solvent, tetraethylene glycol (TTEG), acts as a low-cost fuel to facilitate combustion and the released exothermic energy promotes the nucleation and growth processes of the olivine nanoparticles. In addition, phosphoric acid (used as the phosphorous source) acts as a catalyst to accelerate polyol carbonization. The structure analysis of the as-prepared LiFePO₄/C using X-ray, neutron diffraction and ⁷Li NMR studies suggested the efficacy of the rapid technique to produce highly crystalline phase-pure olivine nanocrystals. The electron microscopy and particle-size distribution studies revealed that the average particle diameters lie below 100 nm and confirmed the presence of a surface carbon layer of 2–3 nm thickness. The thermal and elemental studies indicated that the carbon content in the sample was approximately 5 %. The prepared LiFePO₄/C cathode delivered capacities of 162 mA h g^-1 at 0.1 °C rates with impressive capacity retention for extended cycling. The polyol-assisted pyro-synthesis, which evades the use of external energy sources, is not only a straightforward, simple and timely approach but also offers opportunities for large-scale LiFePO₄/C production.     

The influence of alkaline reserve on the aging behavior of book papers

Degradation of cellulose under alkaline conditions is involved either involuntarily or deliberately in many different cellulose processing steps, such as pulping, bleaching, or aging within the viscose process, and the underlying chemistry has been the topic of numerous studies. When it comes to aging under alkaline conditions—either natural or accelerated (artificial)—the degradation processes are by far less investigated and understood. A prominent example of moderately alkaline cellulosic material is deacidified book paper from libraries which had undergone a mass-deacidification treatment. We studied their aging behavior under accelerated conditions in comparison to non-deacidified duplicates in order to better understand how the alkaline reserve, which was introduced by the deacidification treatment, affects the stability of the books on the long run. GPC analysis of cellulose and determination of carbonyl functionalities were performed, which were critical parameters to achieve a deeper insight into hydrolytic and oxidative changes of cellulose structure upon deacidification treatment and subsequent aging. Also, model book papers impregnated with different amounts of alkaline reserve were used to support the findings from the original book samples. Hydrolytic degradation rates of the original book papers were significantly reduced after mass deacidification compared to the non-deacidified duplicates. The beneficial effect of mass deacidification on cellulose stability was found to be strongly related to the amount of alkaline reserve deposited, independent of varying parameters of book papers. Although some indication of alkali-induced β-elimination was found (a minor decrease of the along-chain carbonyl content in the original deacidified book papers during aging), it did not occur to an extent that significantly influenced the molar mass of cellulose. The beneficial effect of retarded hydrolytic degradation by mass deacidification thus clearly outweighed possible negative alkalinity effects of the deposited alkaline reserve.     

Poly(ethylene glycol)‐crosslinked fullerenes for high efficient phototherapy

Poly(ethylene glycol)‐crosslinked multimeric C₆₀ was developed for use in photothermal/photodynamic therapy of malignant cells. We showed that: (i) the tumor surface temperature on KB tumor‐bearing nude mice treated with multimeric C₆₀ reached about 44 °C; (ii) this hyperthermic condition and tremendous singlet oxygen generation from multimeric C₆₀ resulted in significant tumor volume regression in KB tumor‐bearing nude mice; and (iii) multimeric C₆₀ also efficiently inhibited arthritic progress in the arthritis‐induced DBA/1 J mice model. This multimeric C₆₀ may be useful for photothermal/photodynamic cell ablation in various malignant cells. Copyright © 2012 John Wiley & Sons, Ltd.     

Chemical Composition of a Novel Distillate from Fermented Mixture of Nine Anti-Inflammatory Herbs and Its UVB-Protective Efficacy in Mouse Dorsal Skin via Attenuating Collagen Disruption and Inflammation

Since ancient times, various herbs have been used in Asia, including Korea, China, and Japan, for wound healing and antiaging of the skin. In this study, we manufactured and chemically analyzed a novel distillate obtained from a fermented mixture of nine anti-inflammatory herbs (Angelica gigas, Lonicera japonica, Dictamnus dasycarpus Turcz., D. opposita Thunb., Ulmus davidiana var. japonica, Hordeum vulgare var. hexastichon Aschers., Xanthium strumarium L., Cnidium officinale, and Houttuynia cordata Thunb.). The fermentation of natural plants possesses beneficial effects in living systems. These activities are attributed to the chemical conversion of the parent plants to functional constituents which show more potent biological activities. In our current study, the distillate has been manufactured after fermenting the nine oriental medical plants with Lactobacillus fermentum, followed by distilling. We analyzed the chemical ingredients involved in the distillate and evaluated the effects of topical application of the distillate on ultraviolet B (UVB)-induced skin damage in Institute of Cancer Research (ICR) mice. Topical application of the distillate significantly ameliorated the macroscopic and microscopic morphology of the dorsal skin against photodamage induced by UVB radiation. Additionally, our current results showed that topical application of the distillate alleviated collagen disruption and reduced levels of proinflammatory cytokines (tumor necrosis factor alpha and interleukin 1 β expressions) in the dorsal skin against UVB radiation. Taken together, our current findings suggest that the distillate has a potential to be used as a material to develop a photoprotective adjuvant.     

Melampyrosid,ein neus iridoid aus Melampyrum silvaticum L.

From Melampyrum silvaticum L. (Scrophulariaceae) the new Iridoid melampyrosid (2) was isolated beside aucubin (1). The structure of 2 is determined by spectral data and chemical reactions.     

Synthesis and characterisation of photopolymerisable liquid crystals based on the π-extended fluorene core and their corresponding non-reactive analogues

We have synthesised a series of new reactive mesogens with photopolymerisable di-acrylates and their corresponding non-reactive analogues based on the π-conjugated aromatic core, fluorene (F)-di-[thiophene (T)-benzene (B)], using the Stille and Suzuki coupling reaction. The effect of lateral alkyl chains on the 9-position of the central fluorene moiety as well as α, ω- side alkyl chains attached to the π-conjugated aromatic core on the mesomorphism was investigated by utilising differential scanning calorimetry (DSC) and polarising optical microscopy (POM). A wide angle X-ray scattering (WAXS) study at the various temperatures was also carried out to reveal phase structures. Photopolymerisable di-acrylates connected directly to the rigid aromatic core showed higher phase transition temperatures, probably due to the induced dipole moment in comparison with those of a non-reactive methyl–ether counterpart.     

Luminescence characteristics of minerals separated from irradiated onions during storage under different light conditions

The aim of this study was to determine the effects of light conditions during 2 years of storage on the luminescence characteristics of contaminating minerals, isolated from irradiated onions of 2 different origins. The potential use of photostimulated luminescence (PSL) as a screening and thermoluminescence (TL) as a confirmatory identification method was investigated during post-irradiation periods. Nonirradiated onions had 1,612 photon counts (PCs), However, the irradiated onions had much higher PCs (45,672–469,696, positive). The PCs of the irradiated onions decreased with storage time. However, all the irradiated onions had PCs with positive values (>5,000) even after 2 years of storage except onions stored under natural light. The decline in PCs because of light conditions during storage was in the order of sunlight, artificial light, and a darkroom, respectively. Minerals extracted from the nonirradiated samples exhibited TL glow curves of low intensities with maximum peak after 300 ^°C. However, all irradiated samples had TL glow peaks in the temperature ranges of 185–225 ^°C. The TL intensity and TL ratio of the irradiated samples decreased during storage with a slight shift in the TL peak temperature towards higher temperatures. The TL characteristics were most promising for samples stored under natural light conditions, however all the irradiated onions could be identified even after 2 years of storage.