Structural fluctuation of dimers on Ge(0 0 1) surface near transition temperature

The structural fluctuation of the orientational arrangement of buckled dimers on a Ge(0 0 1) surface near the transition temperature of the order-disorder phase transition is investigated by time-resolving dynamical Monte Carlo simulations. STM images averaged in a finite period are derived from the simulation. The coexistence of the c(4 × 2) and the apparent (2 × 1) domains in the STM images observed by experiments is reproduced in the simulated STM images. We show that the coexistence on the Ge(0 0 1) surface can be attributed to the critical slowing down near the transition temperature.     

GaP Raman Terahertz high accuracy spectrometer and its application to detect organic and inorganic crystalline defects

One of the most important uses of THz spectrometry is to detect defects in molecular structure or in crystals efficiently. We applied GaP Raman THz (GRT) spectrometer to detect and evaluate defects in inorganic and organic materials. High THz-wave absorption due to high defect density of GaSe crystal lowered the efficiency of THz wave generation, when the crystal is used as nonlinear material for DFG (Difference Frequency Generation). Defects in organic molecules could be observed as changes in frequency, intensities of the absorption, and broadenings of the spectra.     

Colloidal titration of aqueous zirconium solutions with poly(vinyl sulfate) by potentiometric endpoint detection using a toluidine blue selective electrode.

Zirconium oxy-salts were hydrolyzed to form positively charged polymer or cluster species in acidic solutions. The zirconium hydrolyzed polymer was found to react with a negatively charged polyelectrolyte, such as poly(vinyl sulfate), and to form a stoichiometric polyion complex. Thus, colloidal titration with poly(vinyl sulfate) was applied to measure the zirconium concentration in an acidic solution by using a Toluidine Blue selective plasticized poly(vinyl chloride) membrane electrode as a potentiometric end-point detecting device. The determination could be performed with 1% of the relative standard deviation. The colloidal titration stoichiometry at pH < or = 2 was one mol of zirconium per equivalent mol of poly(vinyl sulfate).     

Combustion of partially premixed spray jets

Gas turbines, liquid rocket motors, and oil-fired furnaces utilize the spray combustion of continuously injected liquid fuels. In most cases, the liquid spray is mixed with an oxidizer prior to combustion, and further oxidizer is supplied from the outside of the spray to complete diffusion combustion. This rich premixed spray is called “partially premixed spray.” Partially premixed sprays have not been studied systematically although they are of practical importance. In the present study, the burning behavior of partially premixed sprays was experimentally studied with a newly developed spray burner. A fuel spray and an oxidizer, diluted with nitrogen, was injected into the air. The overall equivalence ratio of the spray jet was set larger than unity to establish partially premixed spray combustion. In the present burner, the mean droplet diameter of the atomized liquid fuel could be varied without varying the overall equivalence ratio of the spray jet. Two combustion modes with and without an internal flame were observed. As the mean droplet diameter was increased or the overall equivalence ratio of the spray jet was decreased, the transition from spray combustion only with an external group flame to that with the internal premixed flame occurred. The results suggest that the internal flame was supported by flammable mixture through the vaporization of fine droplets, and the passage of droplet clusters deformed the internal flame and caused internal flame oscillation. The existence of the internal premixed flame enhanced the vaporization of droplets in the post-premixed-flame zone within the external diffusion flame.     

A micropatterned carbohydrate display for tissue engineering by self-assembly of heparin

A novel strategy to construct a fibroblast scaffold on substrates has been demonstrated via top-down photolithography and the subsequent bottom-up processes of molecular self-assembly and molecular recognition. 3-Aminopropyltrimethoxysilane (APS) self-assembled monolayer was micropatterned by photolithography. An anionic polysaccharide heparin was adsorbed selectively on the cationic APS region of the micropatterned substrate. Basic fibroblast growth factor (bFGF) was selectively bound to the displayed heparin region and then micropatterned cultivation of fibroblast cells was successful on the bFGF-heparin-APS substrate.     

Absorption and fluorescence spectra of 9-anthrol and its chemical species in solution

The absorption, fluorescence, and fluorescence-excitation spectra of 9-anthrol (and/or anthrone) have been observed in various solvents, one of which includes a silicon-aluminium ester (diisobutoxyaluminium triethyl silane[(OBu)₂−Al−O−Si−(OEt)₃ SAE]). The fluorescence spectra of 9-anthrol shows peak wavelengths at 442 nm in benzene, 454 nm in methanol, 539 nm in triethylamine, and 550 nm in basic solution, which can be assigned to a neutral, a hydrogen-bonded neutral, an ion pair, and an anionic species of 9-anthrol, respectively. In ethanol solution including SAE, on the other hand, a new fluorescence peak appears at 473 nm. This new band originates from a complex formed between 9-anthrol and SAE. The excited-state ion pair is formed through the hydrogen-bonded form in water and the complex form in triethylamine. CNDO/S calculations support the experimental results.     

Joint Function and Arthropathy Severity in Patients with Hemophilia

Background: The Arnold-Hilgartner classification is one of the most popular evaluation systems for the progression hemophilic arthropathy. A previous study reported an association between arthropathy severity and arc range of motion (ROM). However, associations between arthropathy severity and angular ROM and muscle strength remain unclear. AIM: The purpose of this study was to clarify the association between joint function and arthropathy severity in hemophilia. Methods: We studied the knee, ankle, and elbow joints of 31 patients with hemophilia (PWH). The condition of the affected joints was evaluated on the basis of the interview data, joint function measurements, and roentgenography of the affected joints. In assessment of joint function, we evaluated knee strength (flexor, extensor) and grip strength as well as the passive ROM of the elbow, knee, and ankle. During the interview, all patients were asked about the history of intra-articular bleeding over the past year and pain. Results: As arthropathy severity worsened, knee flexor strength, knee extensor strength, grip strength, and ROM (elbow flexion, elbow extension, knee flexion, knee extension, and ankle extension) significantly decreased. Even patients with mild arthropathies experienced knee extensor weakness and extension limitation. In addition, joint function of severe ankle arthropathy was significantly related to the history of intra-articular bleeding and pain. Conclusion: Our results suggest that physical therapy is necessary to improve joint function in PWH and mild or no arthropathy. Pain control and prophylactic hematological management are necessary for patients with severe arthropathy because intra-articular bleeding and pain significantly decrease joint function.     

Impairing effect of fibrinogen on the mono-/bi-layer form of bovine lung surfactant

Lung surfactant (LS), a lipid–protein mixture responsible for alveolar stability, is inhibited by serum proteins leaked into the lungs in disease. Interaction of bovine lipid extract surfactant (BLES), a clinical replacement lung surfactant, with serum protein fibrinogen (Fbg) was studied employing various structural and biophysical techniques in adsorbed films and bulk bilayer dispersions. Surface tension area isotherms of the adsorbed films revealed the suppression of interfacial activity of BLES by Fbg (adsorption and surface tension reduction). Fbg, predominantly associated with the fluid phase of BLES films, resulted in the aggregation of the gel lipid domains as evidenced by atomic force microscopy. BLES bilayer dispersion showed phase transition from a diffused gel to liquid–crystalline phase in the temperature range 10–35 °C as studied by differential scanning calorimetry (DSC). Fbg resulted in the shift of peak to a higher transition temperature for the maximal heat flow (T _max) of BLES dispersions. Combined Raman and FTIR spectral studies of the BLES/Fbg dispersions revealed that Fbg altered the –CH₂–, –CH₃, and –PO₄ ^? vibrational modes of the phospholipids present in BLES, suggesting the condensing and dehydrating effect of the protein on surfactant. Studies suggest that Fbg, by directly interacting with the gel lipids in LS in bulk dispersions, alter the packing of the films formed at the interface, and can be used as a specific model for lung disease.     

Conjugated Copper–Catecholate Framework Electrodes for Efficient Energy Storage

A conjugated copper(II) catecholate based metal–organic framework (namely Cu-DBC) was prepared using a D₂-symmetric redox-active ligand in a copper bis(dihydroxy) coordination geometry. The π-d conjugated framework exhibits typical semiconducting behavior with a high electrical conductivity of ca. 1.0 S m⁻¹ at room temperature. Benefiting from the good electrical conductivity and the excellent redox reversibility of both ligand and copper centers, Cu-DBC electrode features superior capacitor performances with gravimetric capacitance up to 479 F g⁻¹ at a discharge rate of 0.2 A g⁻¹. Moreover, the symmetric solid-state supercapacitor of Cu-DBC exhibits high areal (879 mF cm⁻²) and volumetric (22 F cm⁻³) capacitances, as well as good rate capability. These metrics are superior to most reported MOF-based supercapacitors, demonstrating promising applications in energy-storage devices.     

A Novel Type of Luciferin from the Siberian Luminous Earthworm Fridericia heliota: Structure Elucidation by Spectral Studies and Total Synthesis

The structure elucidation and synthesis of the luciferin from the recently discovered luminous earthworm Fridericia heliota is reported. This luciferin is a key component of a novel ATP‐dependent bioluminescence system. UV, fluorescence, NMR, and HRMS spectroscopy studies were performed on 0.005 mg of the isolated substance and revealed four isomeric structures that conform to spectral data. These isomers were chemically synthesized and one of them was found to produce light when reacted with a protein extract from F. heliota. The novel luciferin was found to have an unusual extensively modified peptidic nature, thus implying an unprecedented mechanism of action.