An IEF-PCM study of solvent effects on the Faraday {\mathcal{B}} term of MCD

We present the first theoretical investigation of solvent effects on the Faraday ${\mathcal{B}}$ term of magnetic circular dichroism (MCD) at the density–functional level of theory. In our model, the solvent is described by the polarizable continuum model in its integral-equation formulation. We present the extensions required for including electron correlation effects using density–functional theory (DFT) as well as the necessary extensions for including the effects of a dielectric continuum. The new code is applied to the study of the Faraday ${\mathcal{B}}$ term of MCD in a series of benzoquinones. It is demonstrated that electron correlation effects, as described by DFT, are essential in order to recover the experimentally observed signs of the ${\mathcal{B}}$ term. Dielectric continuum effects increase, in general, the magnitude of the ${\mathcal{B}}$ term, leading to an overestimation of the experimental observations in most cases.     

Volumetric properties of the glycyl group of proteins in aqueous solution at high pressures

Sound speeds have been measured for aqueous solutions of alanine and the peptides alanylglycine (alagly), alanylglycylglycine (ala(gly)(2)), alanylglycylglycylglycine (ala(gly)(3)) and alanylglycylglycylglycylglycine (ala(gly)(4)) at T=298.15 K and at the pressures p=0.1, 5.0, 10.0, 20.0, 40.0, 60.0, 80.0 and 100.0 MPa. A method is described whereby reliable partial molar volumes at infinite dilution, Vo2, partial molar isentropic compressions at infinite dilution, Ko(S,2), and partial molar isothermal compressions at infinite dilution, Ko(T,2), for the solutes can be derived from the sound speed data. These results were used to obtain partial molar volumes, isentropic and isothermal compressions for the backbone glycyl group of proteins, CH(2)CONH, over the pressure range p=0.1 to 100.0 MPa. The variations of these properties with pressure are discussed in terms of the likely glycyl-group-water interactions.     

Enamino derivatives of 1,3-dioxoindane-2-carboxylic acid

Although 1,3-dioxoindane-2-carboxylic acid is highly unstable, its enamino derivatives can be isolated by careful hydrolysis of their esters with 2,4-dihydroxy-1,4-naphthoquinone. Crystal structure determination reveals the formation of two intramolecular hydrogen bonds, offering thus a possible explanation for the stability of these acids.     

Bi‐directional ACET micropump for on‐chip biological applications

The ability to control and pump high ionic strength fluids inside microchannels forms a major advantage for clinical diagnostics and drug screening processes, where high conductive biological and physiological buffers are used. Despite the known potential of AC electro‐thermal (ACET) effect in different biomedical applications, comparatively little is known about controlling the velocity and direction of fluid inside the chip. Here, we proposed to discretize the conventional electrodes to form various asymmetric electrode structures in order to control the fluid direction by simple switching the appropriate electric potential applied to the discretized electrodes. The ACET pumping effect was numerically studied by solving electrical, thermal and hydrodynamic multi‐physic coupled equations to optimize the geometrical dimensions of the discretized system. PBS solutions with different ionic strength were seeded with 1 μm sized fluorescent particles and electrothermally driven fluid motion was observed inside the channel for different electrode structures. Experimental analyses confirm that the proposed micropump is efficient for a conductivity range between 0.1 and 1 S/m and the efficiency improves by increasing the voltage amplitude. Behavior of the proposed electrode–electrolyte system is discussed by lumped circuit model. Frequency response of system illustrated that the optimal frequency range increases by increasing the conductivity of medium. For 0.18 S/m PBS solution, the constant pumping effect was observed at frequency range between 100 kHz and 1 MHz, while frequency range of 100 kHz to 5 MHZ was observed for 0.42 S/m. The characteristics of experimental results were in good agreement with the theoretical model.     

The influence of thermo-hygro-mechanical treatment on the micro- and nanoscale architecture of wood cell walls using small- and wide-angle X-ray scattering

Tracking the changes of cellulose crystallites upon thermo-hygro-mechanical treatment is essential to understand the response of wood cell walls to steam and compression. In this paper the influence of Compression combined with Steam (CS) treatment on wood cellulose crystallites and pores structure of Chinese fir (Cunninghamia lanceolata) was studied under different steaming temperatures and compression ratios. Small-angle X-ray scattering and wide-angle X-ray scattering were used to investigate the changes of cellulose crystallites dimension, aspect ratio, fibril diameter distribution, non-crystalline fraction, the number of chains in each microfibril, as well as the fractal dimension and size of pores in response to CS treatment conditions. Results indicate that the crystallinity increased due to CS treatment, but did not show alteration with varying CS treatment conditions, i.e. seemed nearly unaffected by higher temperatures or compression ratio, both for earlywood and latewood. The cellulose crystallite diameter depended on processing parameters: it increased with increasing treatment temperature. No considerable differences were found for earlywood and latewood. We interpret our findings as a rearrangement of adjacent cellulose chains towards higher crystalline perfection attributing to the increase in crystallinity. The same effect allows a larger coherence length of crystalline order and therefore features an increasing cross-sectional dimension. In general we can state that the CS treatment leads to higher crystallinity and more perfectly arranged cellulose crystals, while it does not greatly affect the microfibril diameter but rather the amorphous regions of the microfibrils and the surrounding hemicellulose and lignin.     

Optimization of a biocatalytic single-step alkene cleavage of aryl alkenes

The oxidative cleavage of a CC double bond adjacent to an aryl moiety was achieved in the presence of a protein preparation of Trametes hirsuta G FCC 047 to yield the corresponding aldehydes. Molecular oxygen was the only oxidant required. All positive substrates had a CC bond conjugated to an aromatic system, all other compounds tested not fulfilling this requirement were non-substrates. The optimum reaction conditions are 20 °C, pH 6-6.5, 15% v/v ethanol as co-solvent at an apparent oxygen pressure of 2 bar.     

Electrophoretic methods for analysis of urinary polypeptides in IgA-associated renal diseases

We evaluated the utility of SDS-PAGE/Western blot and CE coupled with MS (CE-MS) for detection of urinary polypeptide biomarkers of renal disease in patients with IgA-associated glomerulonephritides. In a reference cohort of 402 patients with various renal disorders and 207 healthy controls, we defined CE-MS patterns of renal damage and IgA nephropathy (IgAN). In a blinded analysis of a separate cohort of patients with IgAN (n = 10), Henoch-Schoenlein purpura (HSP) with nephritis (n = 10), and IgA-associated glomerulonephritis due to hepatitis C virus (HCV)-induced cirrhosis (n = 9), and healthy controls (n = 12), we compared SDS-PAGE/Western blot and CE-MS against clinical urinalysis for detection of urinary proteins/polypeptides. Urinalysis indicated proteinuria for 50, 90, and 33% of patients, respectively, and for none of the healthy controls. SDS-PAGE/Western blot showed urinary polypeptides abnormality for 90, 80, and 67% of patients, respectively, and for none of the healthy controls. CE-MS indicated a Renal Damage Pattern in 80, 80, and 100 of patients, respectively, and in 17% of healthy controls, with the more specific IgAN Pattern in 90, 90, and 1%, respectively, and in none of the healthy controls. Based on differences in CE-MS patterns, the disease mechanisms may differ among various IgA-associated glomerulonephritides. These exploratory findings should be evaluated in a prospective study with contemporaneous renal biopsy and urinary testing. If validated, it may be feasible to adapt the CE-MS methodology to develop novel tests to detect renal injury at earlier stages, assess clinical manifestations, and monitor responses to therapy in patients with IgA-associated renal diseases.