Communication: probable scenario of the liquid-liquid phase transition of SnI4

We have shown from in situ synchrotron x-ray diffraction measurements that there are two thermodynamically stable liquid forms of SnI(4), depending on the pressure. Based on the liquid-liquid critical point scenario, our recent measurements suggest that the second critical point, if it exists, may be located in a region close to the point at which the melting curve of the crystalline phase abruptly breaks. This region is, unlike that of water, experimentally accessible with relative ease.     

Development of the carboxamide protecting group, 4-(tert-butyldimethylsiloxy)-2-methoxybenzyl

The new carboxamide protecting group, 4-(tert-butyldimethylsiloxy)-2-methoxybenzyl (SiMB), has been developed. While this SiMB group can be removed using mild basic desilylation methods, it can also be deprotected under strongly acidic or oxidative conditions. An application of this group to simple carboxamide groups, as well as to more complex and acid-sensitive adenosine derivatives containing a cyclophane scaffold, was also demonstrated.     

Active thionium species mediated functionalization at the 2α-position of indole derivatives

A combination of dimethyl sulfoxide (DMSO) and trifluoroacetic anhydride (TFAA) mediates functionalization at the 2α-position of indole derivatives. Carbon and heteroatom nucleophiles were directly introduced via a one-pot procedure in excellent yields.     

Color tuning in photofunctional proteins

Depending on protein environment, a single photofunctional chromophore shows a wide variation of photoabsorption/emission energies. This photobiological phenomenon, known as color tuning, is observed in human visual cone pigments, firefly luciferase, and red fluorescent protein. We investigate the origin of color tuning by quantum chemical calculations on the excited states: symmetry-adapted cluster-configuration interaction (SAC-CI) method for excited states and a combined quantum mechanical (QM)/molecular mechanical (MM) method for protein environments. This Minireview summarizes our theoretical studies on the above three systems and explains a common feature of their color-tuning mechanisms. It also discuss the possibility of artificial color tuning toward a rational design of photoabsorption/emission properties.     

Lattice- and network-structure in plastic ice

We have investigated structural and energetic characteristics of plastic ice, which was found in a high pressure region such as 10 GPa by molecular dynamics simulation and free energy calculation. It was predicted that plastic ice intervenes between ice VII and liquid water, in which diffusion is suppressed but rotation is allowed. In the present work, the structure in plastic ice is explored from both local and global view points and focus is placed on the local arrangement, the extent of deviation from the ideal lattice position, and the hydrogen-bonded patterns. The roles of the attractive interaction and the repulsive part of Lennard-Jones potential are also examined. It is found that the higher interaction energy in plastic ice induces a large dislocation of water molecules, which eventually conducts a facile rotation. There are a large amount of hydrogen-bonds which do not orient to the tetrahedral directions. These orientational defects give rise to fusion of the two interpenetrating sublattices of ice VII leading to a plastic phase rather than defect-containing ice VII, which results in a unique network structure of the plastic ice.     

Medical Rehabilitation Need,Case Complexity,and Related Issues among Patients in an Acute Stroke Rehabilitation Setting

This narrative review introduces case complexity and medical rehabilitation needs in a stroke rehabilitation setting, and proposes methods to more efficiently enhance functional recovery in the acute stage after stroke onset. Therapists may measure a construct of individual need complexity around and beyond the basic and common needs for medical necessity, and thereby screen acute patients who could benefit more from additional rehabilitation inputs. This review also describes the clinical significance of medical rehabilitation needs and challenges for efficient stroke rehabilitation. Overall, we propose that challenging research trials should be conducted to compare the effectiveness of the arrangement of rehabilitation service allocation based on needs assessment after stroke with the usual care pathway.     

Detection limit estimated from slope of calibration curve: an application to competitive ELISA.

This paper theoretically derives a general rule that while the slope of the semi-logarithmic plot (Y vs. log X) of a calibration curve varies depending on analyte concentration, X, the slope takes a specific value at the detection limit (L(D)). This rule holds good irrespective of the shape of the calibration curve (linear or non-linear) and in this paper, is applied to competitive ELISA (enzyme linked immunosorbent assay). The following relationship is deduced: slope of log-dose B/B0 at L(D) = [relative standard deviation (RSD) of blank responses] / 0.13. The L(D) obtained from the above-mentioned slope corresponds to the dose at which the RSD of dose estimates is 0.3 (= 30%). A commercial kit for 17alpha-hydroxyprogesterone is taken as an example.     

Molecular-dynamics simulation for the characterization of liquid chromatographic stationary phase: effect of temperature.

The influence of temperature on the surface structure of the octadecylsilica (ODS) bonded phase was investigated with a molecular dynamics (MD) simulation. The MD simulation was applied to a molecular model consisting of three parts: amorphous silica base, dimethyloctadecylsilyl ligands and n-hexane as a mobile phase solvent. More detailed information on the effect of temperature was obtained at the low temperature region than that reported in our previous study. The motion of ODS ligands could be estimated by the mean square displacement (MSD) of the terminal carbon atoms of ODS ligands. The gauche fraction in the ODS ligand conformation can also be estimated to obtain the ligand conformation for each simulation condition in detail. It can be seen that an elevated temperature induced the more bent ligand conformation. The trend has a good agreement to that of the results experimentally observed by using various spectroscopic techniques such as nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), and Raman spectroscopy.     

Submillimeter-wave spectrum of carbonyl sulfide: rare isotopic species

Rotational spectra of four rare isotopic species of OCS were observed in the 110-690 GHz region with a source-modulated submillimeter-wave spectrometer. Spectral lines of ¹⁸O¹³CS, O¹³C³⁶S, ¹⁸OC³⁶S, and ¹⁸O¹³C³⁴S were measured in their natural abundances, 21.4, 1.51, 0.29, and 0.95 ppm, respectively. The rotational constants and centrifugal distortion constants were precisely determined from observed line frequencies by least squares methods. In order to facilitate sensitivity examination in the submillimeter-wave region, transition frequencies and peak absorption coefficients were calculated and tabulated for the spectral lines of the four species up to the 1000 GHz region.