The effect of substrate concentration on biohydrogen production by using kinetic models

The effect of substrate concentration ranging from 0 to 300 g/L on fermentative hydrogen production by mixed cultures was investigated in batch tests using glucose as substrate. The experimental results showed that, at 35℃ and initial pH 7.0, during the fermentative hydrogen production, the hydrogen production potential and hydrogen production rate increased with increasing substrate concentration from 0 to 25 g/L. The maximal hydrogen production potential of 426.8 mL and maximal hydrogen pro-duction rate of 15.1 mL/h were obtained at the substrate concentration of 25 g/L. The maximal hydrogen yield and the maximal substrate degradation efficiency were respectively 384.3 mL/g glucose and 97.6%, at the substrate concentration of 2 g/L. The modified Logistic model could be used to describe the progress of cumulative hydrogen production in this study successfully. The Han-Levenspiel model could be used to describe the effect of substrate concentration on fermentative hydrogen production rate.     

基于磁泳的生物分离分析技术

利用磁场诱导的微粒运动即磁泳对磁响应性粒子进行精细分离,是近年来发展起来的选择性分离细胞和高分子量核酸的有效技术。本文在阐明磁泳分离原理的基础上,介绍了磁泳分离的分流薄层分级技术、四极磁场流动分离技术和微芯片上的自由流磁泳分离技术的装置构造、工作原理及其在生物分离分析中的应用。     

A theoretical study of electronic excited states of photosynthetic reaction center in Rhodopseudomonas viridis

The electronic singlet vertical excited states of photosynthetic reaction center (PSRC) in Rhodopseudomonas (Rps.) viridis were investigated by ZINDO and INDO/S methods. The effects of the interactions of pigment-pigment and pigment-protein on the electronic excitations were examined. The calculation results showed that the interactions of pigment-pigment and pigment-protein play an important role in reasonably assigning the experimental absorption and circular dichroism (CD) spectra of PSRC in Rps. virids. By comparing the theoretically computed excited states with the experimental absorption and CD spectra, satisfactory assignments of the experimental spectroscopic peaks were achieved.     

A Novel UWB Antenna with Small Side-Leakage

A successful design for a UWB (ultra-wideband antennas) antenna based on NRD-guide (nonradiative dielectric waveguide) with small side-leakage is presented. The rule of the theoretical selection of its parameters, if NRD-guide is used as the UWB antennas, is studied firstly, then the temporal propagation characteristics of the NRD-guide and the radiation characteristics for an tapered open-ended NRD-guide are calculated by FDTD (finite-difference time-domain) method.     

Simultaneous Quantification of Seven Main Triterpenoid Saponins in Radix et Rhizoma Clematidis by LC–ELSD

Chinese clematis is a Chinese medicine with anti-inflammatory and anti-rheumatoid properties. Studies showed the triterpenoid saponins of this herb represent the major active components with therapeutic activities for the treatment of inflammatory diseases. The LC–ELSD method was developed to quantitatively analyze seven major triterpenoid saponins in 22 samples from different habitats. The linearity, sensitivity, precision, and accuracy were investigated. It showed the great variation of the contents of each saponin. We concluded clematichinenoside AR is the major saponin in all the samples. This method can be used to effectively evaluate and monitor the quality of Chinese clematis in clinical use.     

Inhibition of J-aggregation of meso-tetra(4-sulfonatophenyl)porphyrin by an ionic liquid with π-conjugated character

Abstract  

UV–visible spectral observations indicate that the J-aggregation of protonated meso-tetra(4-sulfonatophenyl)porphyrin ([H₂TSPP]²⁺) under acidic conditions is completely inhibited by the π–π counteraction between 1-butyl-pyridinium tetrafluoroborate ([bpy]BF₄) and [H₂TSPP]²⁺. The studies also suggest that the intermolecular π–π force is of relative importance for the J-aggregates of [H₂TSPP]²⁺ and the intermolecular electrostatic force for the H-aggregates.     

Novel method for the synthesis of hydrophobic Pt-Ru nanoparticles and its application to preparing a Nafion-free anode for the direct methanol fuel cell

Pt-Ru alloy is a bimetallic catalyst most commonly used in the direct methanol fuel cell (DMFC). In this paper, a new process to synthesize an unsupported Pt-Ru colloid has been introduced. The characteristics of synthesized nanoparticles were identified by XRD, TEM/EDX, and SEM, and it shows that Ru atoms are incorporated into the Pt fcc structure and the well-dispersed particles (diameter approximately 4 nm) possess a Pt-rich feature. This catalyst shows a hydrophobic characteristic which can adsorb very well on the hydrophobic-treated carbon paper or carbon cloth without the need of Nafion. Accordingly, this method can avoid particle agglomeration, and the synthesized catalyst demonstrates strong adsorption with carbon paper. In addition, this colloid-type Nafion-free catalyst was measured via linear sweep voltammetry (LSV) and exhibited electrochemical activity for methanol oxidation comparable to the commercial one with Nafion binding.     

Dehydrogenative Silylation of Alkenes for the Synthesis of Substituted Allylsilanes by Photoredox,Hydrogen‐Atom Transfer,and Cobalt Catalysis

A synergistic catalytic method combining photoredox catalysis, hydrogen‐atom transfer, and proton‐reduction catalysis for the dehydrogenative silylation of alkenes was developed. With this approach, a highly concise route to substituted allylsilanes has been achieved under very mild reaction conditions without using oxidants. This transformation features good to excellent yields, operational simplicity, and high atom economy. Based on control experiments, a possible reaction mechanism is proposed.     

Radioactivity of plutonium isotopes, <Superscript>137</Superscript>Cs and their ratio in sediment,seawater and biota from the east coast of Peninsular Malaysia

This study with sampling expeditions of marine sediment, seawater and biota were performed at 30 stations within Malaysian Exclusive Economic Zone (EEZ). A total of >400 samples were collected to determine the activity concentration of anthropogenic radionuclides (^239+240Pu, ¹³⁷Cs) and their activity ratio (^239+240Pu/¹³⁷Cs) in sediments, seawater and biota. The purpose of this study was to determine the concentration levels for these radionuclides and to evaluate any occurrence of radioactive contamination. Sediment cores were obtained using multicorer device, while water samples via co-precipitation techniques and biota was purchased from local fishermen. The activity concentrations of ^239+240Pu in sediment, seawater and biota were ranged 0.21–0.45 Bq/kg dry wt., 2.33–7.95 mBq/m³ and <0.008 Bq/kg fresh wt., respectively. Meanwhile, the values of ¹³⁷Cs were ranged <1.00–2.71 Bq/kg dry wt. in sediment, 3.40–5.89 Bq/m³ in seawater and <0.05–0.41 Bq/kg fresh wt. in biota, respectively. Activity ratios of ^239+240Pu to ¹³⁷Cs obtained seem to confirm that these artificial radioactivities were mainly due to global nuclear fallout.     

Chiral hierarchical molecular nanostructures on two-dimensional surface by controllable trinary self-assembly

The bottom-up fabrication of surface hierarchical nanostructures is of great importance for the development of molecular nanostructures for chiral molecular recognition and enantioselective catalysis. Herein, we report the construction of a series of 2D chiral hierarchical structures by trinary molecular self-assembly with copper phthalocyanine (CuPc), 2,3,7,8,12,13-hexahexyloxy-truxenone (TrO23), and 1,3,5-tris(10-carboxydecyloxy) benzene (TCDB). A series of flower-like chiral hierarchical molecular architectures with increased generations are formed, and the details of these structures are investigated by high resolution scanning tunneling microscopy (STM). The flower-like hierarchical molecular architectures could be described by a unified configuration in which the lobe of each architecture is composed of a different number of triangular shape building units (TBUs). The off-axis edge-to-edge packing of TBUs confers the organizational chirality of the hierarchical assemblies. On the other hand, the TBUs can tile the surface in a vertex-sharing configuration, resulting in the expansion of chiral unit cells, which thereby further modulate the periodicity of chiral voids in the multilevel hierarchical assemblies. The formation of desired hierarchical structures could be controlled through tuning the molar ratio of each component in liquid phase. The results are significant for the design and fabrication of multicomponent chiral hierarchical molecular nanostructures.