Dynamics of structure and energy of horse carboxymyoglobin after photodissociation of carbon monoxide.

The energetics and structural volume changes after photodissociation of carboxymyoglobin are quantitatively investigated by laser-induced transient grating (TG) and photoacoustic calorimetric techniques. Various origins of the TG signal are distinguished: the phase grating signals due to temperature change, due to absorption spectrum change, and due to volume change. We found a new kinetics of approximately 700 ns (at room temperature), which was not observed by the flash photolysis technique. This kinetics should be attributed to the intermediate between the geminate pair and the fully dissociated state. The enthalpy of an intermediate species is determined to be 61 +/- 10 kJ/mol, which is smaller than the expected Fe-CO bond energy. The volume of MbCO slightly contracts (5 +/- 3 cm(3)/mol) during this process. CO is fully released from the protein by an exponential kinetics from 25 to -2 degrees C. During this escaping process, the volume expands by 14.7 +/- 2 cm(3)/mol at room temperature and 14 +/- 10 kJ/mol is released, which should represent the protein relaxation and the solvation of the CO (the enthalpy of this final state is 47 +/- 10 kJ/mol). A potential barrier between the intermediate and the fully dissociated state is DeltaH(*) = 41.3 kJ/mol and DeltaS(*) = 13.6 J mol(-1) K(-1). The TG experiment under a high wavenumber reveals that the volume expansion depends on the temperature from 25 to -2 degrees C. The volume changes and the energies of the intermediate species are discussed.     

Behavior of Mn3+ ions in four-layered hexagonal (Sr1−x−yLaxBay)MnO3

Stoichiometric four-layered hexagonal (4H) (Sr_1?x?yBa_xLa_y)MnO₃ was synthesized using a standard ceramic technique. Rietveld analysis at room temperature indicated that the Mn–O(1) distance increased and the Mn–O(2) distance decreased with the increase in x. The samples were n-type semiconductors and exhibited hopping conductivity in a small-polaron model below 533 K. The Mn³⁺ ion acted as a donor and the electron transfer became active through the Mn³⁺–O–Mn⁴⁺ path. The samples were antiferromagnetic and the Néel temperature (T_N) was constant regardless of y when x was fixed to 0.3, whereas T_N shifted to a high temperature when y was fixed to 0.02. The face-sharing Mn³⁺–O(2)–Mn⁴⁺ interaction strengthened as the Mn–O(2) distance decreased, and T_N shifted to a high temperature as a result.     

Retroperitoneal ancient schwannoma presenting as an adrenal incidentaloma: CT and MR findings

A 35-year-old woman was referred to our institution for additional examinations to evaluate bilateral suprarenal masses incidentally found on abdominal ultrasonographic images obtained during an annual medical health checkup. Our computed tomographic scans showed bilateral and well-circumscribed low-density suprarenal masses, while MRI revealed the tumors to be heterogeneous with low intensity on T₁-weighted images and high intensity on T₂-weighted images. A laparoscopic adrenalectomy was performed under the suspicion of a malignant tumor, such as a malignant fibrous histiocytoma. Pathologic findings indicated a retroperitoneal ancient schwannoma of two histologic types: Antoni A and Antoni B. We considered that elucidation of the characteristic features of a schwannoma would provide helpful preoperative information for diagnosis.     

A new class of rhodamine luminophores: design, syntheses and aggregation-induced emission enhancement

A new class of rhodamine luminophores, 3',3'-bis(oxospiroisobenzofuran)-3,7-bis(dialkylamino)benzopyrano-xanthene derivatives (ABPX), have been successfully developed. The emission behavior of ABPX series is directly opposite to the concentration quenching of conventional rhodamine dyes. ABPX series exhibit aggregation-induced emission enhancement (AIEE).     

Anti-inflammatory sesquiterpenes from Curcuma zedoaria

From the methanolic extract of the rhizome of Curcuma zedoaria, we isolated anti-inflammatory sesquiterpene furanodiene (1) and furanodienone (2) along with new sesquiterpene compound 3 and known eight sesquiterpenes, zederone (4), curzerenone (5), curzeone (6), germacrone (7), 13-hydroxygermacrone (8), dehydrocurdione (9), curcumenone (10), and zedoaronediol (11). Their structures were elucidated on the basis of spectroscopic data. The anti-inflammatory effect of isolated components on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation of mouse ears were examined. Compounds 1 and 2 suppressed the TPA-induced inflammation of mouse ears by 75% and 53%, respectively, at a dose of 1.0 micromol. Their activities are comparable to that of indomethacin, the normally used anti-inflammatory agent.     

Rücktitelbild: C?H Activation Generates Period‐Shortening Molecules That Target Cryptochrome in the Mammalian Circadian Clock (Angew. Chem. 24/2015)

The synthesis and functional analysis of KL001 derivatives, which are modulators of the mammalian circadian clock, are described. By using cutting‐edge C H activation chemistry, a focused library of KL001 derivatives was rapidly constructed, which enabled the identification of the critical sites on KL001 derivatives that induce a rhythm‐changing activity along with the components that trigger opposite modes of action. The first period‐shortening molecules that target the cryptochrome (CRY) were thus discovered. Detailed studies on the effects of these compounds on CRY stability implicate the existence of an as yet undiscovered regulatory mechanism.     

Microwave-induced delayed phosphorescence studies of the total and radiationless decay processes of 3ππ* aromatic carbonyls

We have investigated the details of the radiationless decay processes of ³ππ* aromatic carbonyls of benzaldehyde type using microwave-induced delayed phosphorescence (MIDP) technique. Correlations between the decay rates from the spin sublevels and the energy separations between the ³ππ* and ³nπ* state (ΔE _TT) and those between the ³ππ* and ¹ππ* states (ΔE _ST) were examined in detail for a series of systems. It is shown that the decay rates from the z and x sublevels depend on both ΔE _TT and ΔE _ST strongly, but the y sublevel decay is independent of them. An empirical model to explain the correlations among the decay rates, ZFS, ΔE _TT and ΔE _ST is presented. It is shown that the decays from the z and x sublevels of the ³ππ* aromatic carbonyls are dominantly radiationless and are primarily determined by the mixing with the ¹nπ* states unless ΔE _TT is very small. On the other hand, the radiationless decay from the y sublevel is likely due to the mixing with the ¹σπ* (¹πσ*) states. The mechanism for the radiationless decay from each spin sublevel is discussed in view of the results obtained.     

Revised structure of tetrapetalone A and its absolute stereochemistry

The chemical structure of tetrapetalone A (1), a novel lipoxygenase inhibitor from Streptomyces sp., was revised by using the ¹H-¹⁵N HMBC technique. Furthermore, the absolute stereochemistry of all the asymmetric carbons in 1 was determined based on the detailed NOE data of 1 and its derivative.     

Binding of poly(amido amine) dendrimer to sodium hyaluronate in aqueous NaCl solution

Binding of poly(amido amine) dendrimer to sodium hyaluronate (NaHA) in aqueous 0.25 M NaCl solution has been investigated by static light scattering. It was observed that the apparent weight-average molecular weight and the radius of gyration increase with the ratio of NH(2) terminal groups in the dendrimer to the carboxylate groups in the NaHA, [NH(2)]/[COO(-)]. Up to [NH(2)]/[COO(-)]=31, the observed variation of molecular weight was reproduced by the "average binding" model, where an average number of dendrimers binds to each NaHA chain. Based on the "critical binding" model, the maximum number, n(max), of dendrimers which can bind to a NaHA chain was calculated to be n(max)=300 for a solution of [NH(2)]/[COO(-)]=56. The obtained value corresponds to the binding of one dendrimer per 1.5 repeating units on a NaHA chain. It is suggested from the observed radius of gyration that, while the dendrimer-NaHA complexes of [NH(2)]/[COO(-)] up to 5 maintain a wormlike character similar to NaHA without bound dendrimers, those of [NH(2)]/[COO(-)] above 10 behave like rigid rods. It is concluded that the hydrogen-bonding interaction, besides the electrostatic interaction, should play an important role in the formation of the NaHA-dendrimer complexes.