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Recent applications of decellularized tissues include the ectopic use of sheets and powders for three-dimensional (3D) tissue reconstruction. Decellularized tissues are modified (or fabricated) with the desired functions for application to the target (transplanted or used) tissue, including soft-hard interregional tissues, such as ligaments, tendons, and periodontal ligaments. This study aimed to prepare a mineralized decellularized pericardium to construct a soft-hard interregional tissue by 3D fabrication of decellularized pericardium, for example, rolling up to a cylindrical form. The decellularized pericardial tissue was prepared using the high hydrostatic pressurization (HHP) and surfactants method. The pericardium consisted of bundles of aligned fibers, and the bundles were slightly disordered when prepared with the surfactant decellularization method compared with that prepared using the HHP decellularization method. Mineralization of the decellularized pericardium was performed using an alternate soaking process with various cycles. The surface of the decellularized pericardium was covered with calcium phosphate precipitates, which accumulated on the surface with an increasing number of soaking cycles. The inside of the HHP decellularized pericardium was mineralized uniformly, whereas the mineralization of the decellularized pericardium decreased toward the interior. These findings suggest that the decellularization method strongly affects the structure and mineralized parts of the decellularized pericardium. The mineralized decellularized pericardium could be a candidate material for reconstructing alternative interregional tissues, such as ligaments and tendons.

The aim of this study was to determine an in vitro evaluation method that could directly predict in vivo performance of decellularized tissue for cardiovascular use. We hypothesized that key factors for in vitro evaluation would be found by in vitro assessment of decellularized aortas that previously showed good performance in vivo, such as high patency. We chose porcine aortas, decellularized using three different decellularization methods: sodium dodecyl-sulfate (SDS), freeze-thawing, and high-hydrostatic pressurization (HHP). Immunohistological staining, a blood clotting test, scanning electron microscopy (SEM) analysis, and recellularization of endothelial cells were used for the in vitro evaluation. There was a significant difference in the remaining extracellular matrix (ECM) components, ECM structure, and the luminal surface structure between the three decellularized aortas, respectively, resulting in differences in the recellularization of endothelial cells. On the other hand, there was no difference observed in the blood clotting test. These results suggested that the blood clotting test could be a key evaluation method for the prediction of in vivo performance. In addition, evaluation of the luminal surface structure and the recellularization experiment should be packaged as an in vitro evaluation because the long-term patency was probably affected. The evaluation approach in this study may be useful to establish regulations and a quality management system for a cardiovascular prosthesis.

Recent applications of decellularized tissue have included the use of hydrogels for injectable materials and three-dimensional (3D) bioprinting bioink for tissue regeneration. Microvascular formation is required for the delivery of oxygen and nutrients to support cell growth and regeneration in tissues and organs. The aim of the present study was to evaluate the formation of capillary networks in decellularized extracellular matrix (d-ECM) hydrogels. The d-ECM hydrogels were obtained from the small intestine submucosa (SIS) and the urinary bladder matrix (UBM) after decellularizing with sodium deoxycholate (SDC) and high hydrostatic pressure (HHP). The SDC d-ECM hydrogel gradually gelated, while the HHP d-ECM hydrogel immediately gelated. All d-ECM hydrogels had low matrix stiffness compared to that of the collagen hydrogel, according to a compression test. D-ECM hydrogels with various elastic moduli were obtained, irrespective of the decellularization method or tissue source. Microvascular-derived endothelial cells were seeded on d-ECM hydrogels. Few cells attached to the SDC d-ECM hydrogel with no network formation, while on the HHP d-ECM hydrogel, a capillary network structure formed between elongated cells. Long, branched networks formed on d-ECM hydrogels with lower matrix stiffness. This suggests that the capillary network structure that forms on d-ECM hydrogels is closely related to the matrix stiffness of the hydrogel.

Due to an increasing number of cardiovascular diseases, artificial heart valves and blood vessels have been developed. Although cardiovascular applications using decellularized tissue have been studied, the mechanisms of their functionality remain unknown. To determine the important factors for preparing decellularized cardiovascular prostheses that show good in vivo performance, the effects of the luminal surface structure of the decellularized aorta on thrombus formation and cell behavior were investigated. Various luminal surface structures of a decellularized aorta were prepared by heating, drying, and peeling. The luminal surface structure and collagen denaturation were evaluated by immunohistological staining, collagen hybridizing peptide (CHP) staining, and scanning electron microscopy (SEM) analysis. To evaluate the effects of luminal surface structure of decellularized aorta on thrombus formation and cell behavior, blood clotting tests and recellularization of endothelial cells and smooth muscle cells were performed. The results of the blood clotting test showed that the closer the luminal surface structure is to the native aorta, the higher the anti-coagulant property. The results of the cell seeding test suggest that vascular cells recognize the luminal surface structure and regulate adhesion, proliferation, and functional expression accordingly. These results provide important factors for preparing decellularized cardiovascular prostheses and will lead to future developments in decellularized cardiovascular applications.

This study aimed to clarify the factors related to self-efficacy experienced by psychiatric nurses. Analysis of qualitative descriptive data from a free self-description questionnaire administered to 16 psychiatric nurses working in psychiatric hospitals revealed 24 codes across the following 8 categories as factors that increase self-efficacy: A1. possibility of practical use in nursing, A2. nursing judgment, A3. improvement of psychiatric symptoms, A4. the patients presenting a positive attitude, A5. building a relationship of trust with the patients, A6. building a relationship of trust with other nurses, A7. work progressing according to plan and A8. team medical practice. Twenty-five codes across the following 10 categories were identified as factors that decrease self-efficacy: B1. lack of communication, B2. uncertainty in caregiving, B3. recurrence of psychiatric symptoms, B4. feeling overpowered by a patient, B5. sense of being too busy to work adequately, B6. difficulty in bringing about self-improvement, B7. sense of loss regarding one's role as a nurse, B8. lack of physical strength, B9. mechanical performance of nursing and B10. fluctuating view of nursing due to mistakes. These factors require intervention for psychiatric nurses' self-efficacy.

This paper investigates the vibration of one-degree-of-freedom magnetically levitated body. Especially, the influences of the nonlinearity of the system and the dynamical characteristics of electric circuit and magnetic circuit are focused. This paper's object is extended to the case that electric current supplied from a power-operational amplifier is limited in a positive range. Thus, the system may have piecewise nonlinearity when the vibration amplitude is large. The nonlinear analysis for this system is discussed. The dynamical characteristics of the system are clarified by numerical simulation and theoretical analysis. These obtained results are confirmed by experiment.

Six C3 cyclic trinuclear complexes [{M(Cp*)(L)}3]3+ (M = RhIII and IrIII; Cp* = η5–C5Me5) containing adenosine nucleosides [L: adenosine (Hado), 2′-deoxyadenosine (Hdeoado) and 5′-acetyl-2′,3′-isopropylideneadenosine (Haipado)] were prepared and characterized by UV/Vis and circular dichroism (CD) spectra, NMR spectroscopy, electrospray ionization mass spectroscopy and X-ray crystal structure analysis. The isolations of one and/or two diastereomers were successfully carried out for the four systems by second-order asymmetric transformation and/or fractional crystallization. Interestingly, a striking kinetic difference was found between the present RhIII– and IrIII–ado systems. The crystal structure of CCC-[{Rh(Cp*)(ado)}3](CF3SO3)3·2.5H2O·CH3OH revealed that the ado ligand adopts a μ-1κN1:2κ2N6,N7 bridging mode and the three purine rings forming a triangle dome-like cavity can include one methanol molecule into its cavity. The absolute configurations were assigned to these complexes based on the crystal structural result and CD spectral arguments. The RhIII–N-methyl adenosine (HNMeado) system exceptionally gave a di-μ-hydroxy anti-dinuclear structure because of the weak coordination ability of the N(6) donor.

Optically active 2-thiazolidinecarboxylic acid (2-THC), a substrate for D-amino acid oxidase in animal kidney, is known to undergo racemization quickly in solution. The association of (+)- and (−)-2-THC with antimony potassium tartrate K2[Sb2(L or D-tart)2] was studied by electrospray ionization mass spectrometry (ESI-MS). We observed that relative intensities of associated ions in acetonitrile/water solution were changing as the racemization progressed. For [Sb2(L-tart)2]2−, the intensities of the associated ions increased as (+)-2-THC underwent racemization to a (−)-isomer; on the other hand, the intensity of the associated ion decreased as (−)-2-THC underwent racemization to a (+)-isomer. In the case of [Sb2(D-tart)2]2−, an opposite effect on the intensities of the associated ions was observed. The change in the intensities of associated ions can be used for chiral recognition of (+)-2-THC and (−)-2THC. Stereochemical models of the association of the optical isomers with [Sb2(L- or D-tart)2]2− were constructed from the consideration of both hydrogen bonding of NH-O functions and HSAB (hard and soft acids and bases) interaction of S and Sb atoms. Comparison of the stereochemical models with the ESI-MS results enabled us to predict the absolute configurations of the 2-THC isomers. Copyright © 2001 John Wiley & Sons, Ltd.

High-energy collision-induced dissociation (CID) experiments on polycyclic aromatic hydrocarbons (PAHs) having 2-6 rings, naphthalene, anthracene, phenanthrene, fluoranthene, pyrene and coronene, were performed, and the relative abundances of their fragment ions were investigated as a function of collision energy. The results revealed that the PAHs except naphthalene showed a bimodal-type distribution of positive fragmentation ions, which is closely similar to the fragment-ion distribution reported for the CID of three-dimensional fullerene, C(60)(+) and C(70)(+). The three-ring isomers of anthracene and phenanthrene and the four-ring isomers of fluoranthene and pyrene can be distinguishable in their spectra under an electron ionization energy of 70 eV, but the high-energy CID spectra of the three- and four-ring isomers were almost identical. The fragmentation corresponding to fragment ions in the low-mass region of the bimodal CID spectra could be interpreted by the simple statistical model that fragment ions are formed by random evaporation from the molecular ions after a considerable structural rearrangement, 'phase transition', occurring at some high-energy state.

[Pt(hfac)2] (hfac: hexafluoroacetylacetonate) reacts with MeNH2 in CH2Cl2/MeOH to give an –NHMe adduct complex on one of the carbonyl carbons, (MeNH3)[Pt(hfac)(hfac–NHMe)] 1 which is a tetrahedral intermediate of a Schiff base complex, [Pt(CF3COCHC(Nme)CF3)2] 2. Complex 1 activates H2O, MeOH, MeNO2 or acetone in solution to form the corresponding conjugate base adducts. The C–C bond in –CH2NO2 adduct 6, easily cleaves and generates nitromethane in solution.

The chiral recognition of metal complexes by a quick and sensitive mass spectrometric analysis was investigated. The principle is introduction of an external chiral standard compound and detection of the differential association with two optical isomers. Using electrospray ionization mass spectrometry we detected weak intermolecular association between the external chiral anion bis(μ-L-, D-tartrato)-diantimonate(III), [Sb2(L-, D-tart)2]2− and isomeric bis(L-alaninate) ethylenediamine cobalt(III) complex ions, [Co(L-ala)2(en)]+ in acetonitrile/water solution. The difference in the association with optical isomers of the Co complex was measured. The results were interpreted based on a model of intermolecular interaction involving hydrogen bonding. The prospects of the mass spectrometry method for chiral recognition using the external chiral negative ion [Sb2(L-, D-tart)2]2− was discussed.