Use of organic solvents in large research institutions in Japan

OBJECTIVES

Laboratories in research institutions use organic solvents in research and development. Nevertheless, the types of solvents in use have been seldom reported. This study was initiated to elucidate types of organic solvents used in large research institutions in Japan, with a focus on possible different use among research fields.

METHODS

In 2010-2011, 4517 laboratories in seven large research institutions were visited. In accordance with legal stipulations, air in each laboratory was collected in polyvinyl fluoride bags and analyzed by direct injection into a gas-chromatograph for 47 types of organic solvents. In evaluation, the laboratories were grouped by 5 research fields, i.e., agriculture, biology, medicine, natural science, and technology and engineering.

RESULTS

Types of organic solvents commonly used in research activities were not diverse. Those commonly used were chloroform and 1,2-dichloroethane out of 7 Group 1 organic solvents (with high toxicities); 6 organic solvents, i.e., acetone and methyl alcohol in general, ethyl acetate, hexane and toluene in technology and engineering laboratories; and xylenes in medical fields out of 40 Group 2 organic solvents (with relatively low toxicities). Judging from solvent vapor concentrations, work environments in more than 99 % of laboratories were considered adequate. Nevertheless, use of chloroform in high-performance liquid chromatography (HPLC) resulted in inadequate environments in 30 laboratories (0.7 %).

CONCLUSIONS

Organic solvents commonly used were not very diverse. Work environments in research laboratories were generally good, but the environment with use of chloroform in HPLC analysis remained yet to be improved.

Cryopreservation of osteoblasts by use of a programmed freezer with a magnetic field

In order to determine a suitable condition for osteoblasts cryopreservation, murine osteoblasts were freezed by programmed freezer with a magnetic field (CAS freezer). After 7 days cryopreservation at -150°, the number of survival cells immediately after thawing and the growth rate of cultured cells for 48 hours were examined. Gene and protein expression of alkaline phosphatase (ALP), osteopontin (OPN) and bone sialoprotein (BSP) were compared between cryopreserved and non-cryopreserved groups. As a result, a plunging temperature of -30°, a hold-time at -5° for 15 minutes and a 0.1 mT of magnetic field led to the largest survival and growth rate. Moreover, there was no significant difference in ALP, OPN and BSP mRNA and protein expression between cryopreserved and control groups. From these results, it was suggested that the CAS freezer is available for osteoblast cryopreservation and bone tissue banking can be established in the future.

Synthesis and characterization of antiapicophilic arsoranes and related compounds

Utilizing bulky bidentate ligand systems with C(2)F(5) and n-C(3)F(7) groups, antiapicophilic arsoranes (5b and 5c, respectively) were synthesized. A kinetic study on the isomerization of these arsoranes to their more stable isomers showed that the barriers increased in the order of CF(3) < C(2)F(5) < n-C(3)F(7) in accord with their steric bulk. It was also revealed that the degree of freezing isomerization was larger for the change from CF(3) to C(2)F(5) than from C(2)F(5) to n-C(3)F(7), obvious from the differences in activation free energy at 363 K of 1.6 and 0.3 kcal mol(-1), respectively. X-ray structural analysis of several precursors of these two systems disclosed the unique structures of these compounds.

The photonuclear neutron and gamma-ray backgrounds in the fast ignition experiment

In the fast-ignition scheme, very hard x-rays (hereinafter referred to as γ-rays) are generated by Bremsstrahlung radiation from fast electrons. Significant backgrounds were observed around the deuterium-deuterium fusion neutron signals in the experiment in 2010. In this paper the backgrounds were studied in detail, based on Monte Carlo simulations, and they were confirmed to be γ-rays from the target, scattered γ-rays from the experimental bay walls (γ'-rays), and neutrons generated by (γ, n) reactions in either the target vacuum chamber or the diagnostic instruments (γ-n neutrons).

Broken local symmetry in paraelectric BaTiO3 proved by second harmonic generation

Precursor dynamics of a cubic to tetragonal ferroelectric phase transition in BaTiO3 is studied by the accurate measurement of the second harmonic generation (SHG) integral intensities. A finite signal holds for the SHG integrated intensity above the ferroelectric Curie temperature T(c)=403  K. Above the Burn's temperature T(d)≈580  K, the power law with the exponent γ=1 shows normal SHG nature originating from the hyper-Raman scattering by dynamical polar excitations, while, below T(d), a SHG signal from polar nanoregions becomes dominant with the larger exponent γ=2. Such a crossover of the power law exponent near T(d) is discussed on the basis of the effective Hamiltonian method and Monte Carlo simulation.

Temperature-dependent Raman scattering study of the defect pyrochlores RbNbWO6 and CsTaWO6

Lattice dynamics calculations and temperature-dependent Raman scattering experiments were performed on RbNbWO(6) and CsTaWO(6) pyrochlore oxides. The observed bands were assigned to the respective motions of atoms in the unit cell. The spectra showed the presence of additional Raman bands not allowed for by the [Formula: see text] cubic structure. We have shown that these bands appear due to both substitutional disorder in the 16c sites and displacive disorder of the A ions. Raman studies also revealed the presence of an additional 80 cm(-1) band at room temperature for RbNbWO(6), not observed for CsTaWO(6). The presence of this band has been attributed to off-center displacement of the Nb and W ions due to structural phase transition into a tetragonal ferroelectric phase. The temperature evolution of the 80 cm(-1) band intensity revealed that it disappeared at a much higher temperature (about 650 K) than the reported phase transition temperature (about 360 K). This behavior is reminiscent of chemically disordered perovskite ferroelectrics, including relaxor ferroelectrics, and was attributed to the presence of small polar regions with local tetragonal distortion embedded in the paraelectric matrix of the [Formula: see text] structure.

Maternal contact differentially modulates central and peripheral oxytocin in rat pups during a brief regime of mother-pup interaction that induces a filial huddling preference

Central oxytocin mediates the acquisition of a filial preference for maternal odour in rat pups, manifested by their huddling preferences. The present study was designed to examine whether maternal care modulates oxytocin concentrations in rat pups and, if so, how different types of maternal contact are associated with the pups' oxytocin concentrations. Pairs of 14-day-old littermates were removed from their home cage for 1 h and then placed with a lactating foster mother for 2 h, or they remained isolated at room temperature. Enzyme immunoassays revealed that maternal care and maternal separation can differentially modulate pups' oxytocin concentrations. Both hypothalamic and serum oxytocin increased during the 1-h separation. Pups placed with a foster mother after the separation maintained the same concentrations in the hypothalamus and serum through the fostering period. By contrast, pups placed with no mother showed a further increase in hypothalamic oxytocin but serum oxytocin decreased. Behavioural analyses revealed that skin-to-skin contact with the mother, but not simple physical contact or maternal licking/grooming, was positively correlated with the pups' hypothalamic oxytocin concentrations. These neuroendocrine data match previous findings showing that skin-to-skin contact with mother facilitates the acquisition of the pups' huddling preference for a maternally-associated odour. Taken together, the present study suggests that maternal skin-to-skin contact stimulates pups' central oxytocin, at the same time as creating the conditions for inducing a preference for maternal odour and establishing a social affiliation in rat pups; the natural schedule of maternal separation and reunion may modulate pups' oxytocin concentrations, providing scaffolding for the acquisition of their filial huddling preference.

Synthesis and characterization of the most distorted 16π porphyrin: 16π octaisopropyltetraphenylporphyrin (OiPTPP)

Previously unreported octaisopropyltetraphenylporphyrin (OiPTPP) was prepared from 3,4-diisopropylpyrrole, an unstable previously unisolated heterocyclic compound. Purification of the free-base 18π porphyrin required conversion to its 18π zinc(II) complex, chromatographic separation, and acid mediated demetalation. Oxidation of the 18π porphyrin with SbCl5 furnished metal-free 16π octaisopropyltetraphenylporphyrin (OiPTPP). X-ray structural determination revealed that the novel species is the most distorted 16π porphyrin to date. The time course of decomposition of the oxidized species monitored by UV-vis spectra implied that the introduction of high steric repulsion was effective for enhancing stability of the 16π porphyrin. The reaction of metal-free 16π OiPTPP with LiBF4 followed by Pd2(dba)3 gave the corresponding 18π OiPTPP palladium(II) complex via reduction of the OiPTPP lithium(I) complex as previously reported for 16π octaisobutyltetraphenylporphyrin (OiBTPP). The new 18π porphyrin system could be characterized by the X-ray analysis of the 18π OiPTPP palladium(II) complex. The X-ray structure of the 18π metal complex also indicated that the distortion of the porphyrin ring had become larger than that of previously known 18π porphyrins