Beta and gamma decays of J π = 1+, 24mAl state

A β-γ spectroscopy of the J ^π , 426 keV isomeric state of ²⁴Al (^24m Al) has been carried out by using a ²⁴Al secondary beam with high purity and high isomeric ratio. From the absolute γ-ray and β-particle intensities observed in the decay of the isomeric state, the branching ratio R _B of the isomeric γ decay from ^24m Al to the J ^π = 4⁺, ground state of ²⁴Al have been derived. The obtained R _B value of 69.6(7)% is much smaller than the previously accepted value of 82.5(30)%. The precise half-life for the isomer decay, T _1/2 ^m = 130.9(13) ms, has been also determined in this experiment. Accordingly, the M3 γ-decay strength B(M3) of the ^24m Al decay becomes smaller and the total β-decay branching ratio becomes larger. In particular, the β-decay branching ratio to the ground state of ²⁴Mg becomes 24.3(9)%, which is 2.4 times larger than the previous value of 10.1(28)%. By combining the branching ratio and the half-life, the Gamow-Teller (GT) transition strength B(GT) of 0.0194(7) is deduced for the GT transition from ^24m Al to the J ^π = 0⁺, ground state of ²⁴Mg. This value is in good agreement with the values derived from charge-exchange reactions.     

Quantum protocols for untrusted computations

In this paper, we propose new quantum arithmetic protocols among multiple parties. Let some parties have values. A problem is to find a protocol such that under the condition that any eavesdropper intercepting any quantum system being exchanged among the parties must not be able to acquire information, the parties compute an arithmetic operation such as addition and multiplication, and transfer its computing result to another party. One of main ideas to solve this problem is based on operating state phases. A quantum addition algorithm based on operating phases has been proposed by Draper, but his algorithm was not considered being eavesdropped. We propose secure quantum arithmetic protocols.     

Hyperfine Interactions of Short-Lived β Emitters in Pd

The Knight shifts K and the spin-lattice relaxation time T ₁ for the short-lived β-emitters ¹²B and ¹²N implanted into Pd have been measured by means of the β-NMR method. The results show that K depends on temperature. The obtained values of experimental K were compared with theoretical values derived with the KKR method.     

Silica gel-promoted synthesis of 3,4,5-triaryltetrahydro-1,4-thiazine derivatives from β,β′-dichloro sulfides and aromatic amines

A novel and efficient synthesis of 3,4,5-triaryltetrahydro-1,4-thiazine derivatives by treatment of β,β′-dichloro sulfides, 2:1 adducts of alkenes and sulfur dichloride, with aromatic amines in the presence of silica gel is described. The silica gel can be easily recovered and reused in up to four consecutive reactions without any significant decrease in product yield.     

Chemical states of localized Fe atoms in ethylene matrices using in-beam Mössbauer spectroscopy

The reaction products of isolated single iron atoms in a low concentration matrix of ethylene were studied using in-beam Mössbauer spectroscopy with a short-lived ⁵⁷Mn (T _1/2=1.45 m) beam. The in-beam Mössbauer spectrum of ⁵⁷Fe arising from ⁵⁷Mn in a matrix of ethylene and argon measured at 16 K was analyzed with four components. Density functional theory calculations were carried out to confirm the assignments. It was suggested that the reaction produced monoiron species of Fe(C ₂ H ₄) with a spin state of S = 2.     

Mössbauer spectra obtained using β − γ coincidence method after 57Mn implantation into LiH and LiD

Highly energetic ⁵⁷Mn (T_1/2 = 1.45 m) was generated by nuclear projectile fragmentation in a heavy-ion accelerator, and implanted into lithium hydride (LiH) and lithium deuteride (LiD) at 578 K. Mössbauer spectroscopy with β ? γ coincidence detection was then carried out on the ⁵⁷Fe obtained from β^?decay of the ⁵⁷Mn to study the time dependence of the site distributions and coordination environments of dilute Fe atoms implanted in the LiH and LiD. The results suggest that the Fe atoms can substitute for either the Li and H or D atoms within 100 ns. Additionally, the displacement behavior of the substitutional ⁵⁷Fe atoms on the lattice sites is discussed.     

New metal-organic frameworks with large cavities: selective sorption and desorption of solvent molecules

Five novel transition metal complexes [Cd(II) (3)(tpba-2)(2)(SCN)(6)].6 THF.3 H(2)O (1), [Cu(II) (3)(tpba-2)(2)(SCN)(6)].6 THF.3 H(2)O (2), [Ni(II) (3)(tpba-2)(2)(SCN)(6)].6 THF.3 H(2)O (3), [Cd(II) (2)(tpba-2)(SCN)(3)]ClO(4) (4), [Cu(I) (3)(SCN)(6)(H(3)tpba-2)] (5) [TPBA-2 = N',N',N'-tris(pyrid-2-ylmethyl)-1,3,5-benzenetricarboxamide, THF=tetrahydrofuran] were obtained by reactions of the corresponding transition metal salts with TPBA-2 ligand in the presence of NH(4)SCN using layering or solvothermal method, respectively. The results of X-ray crystallographic analysis showed that complexes 1, 2 and 3 are isostructural and have the same 2D honeycomb network structure with Kagomé lattice, in which all the M(II) (M = Cd, Cu, Ni) atoms are six-coordinated, and the TPBA-2 ligands adopt cis,cis,cis conformation while the thiocyanate anions act as terminal ligands. Capsule-like motifs are found in 1, 2 and 3, in which six THF molecules are hosted, and the results of XPRD and solid-state (13)C NMR spectral measurements showed that the compound 1 can selectively desorb and adsorb THF molecules occurring along with the re-establishment of its crystallinity. In contrast to 1, 2 and 3, complex 4 has different 2D network structure, resulting from TPBA-2 ligands with cis,trans,trans conformation, thiocyanate anions serving as end-to-end bridging ligands, and the incomplete replacement of perchlorate anions, which further link the 2D layers into 3D framework by the hydrogen bonds. In complex 5, the Cu(II) atoms are reduced to Cu(I) during the process of solvothermal reaction, and the Cu(I) atoms are connected by thiocyanate anions to form a 3D porous framework, in which the protonated TPBA-2 ligands are hosted in the cavities as templates.     

Design of peptides that form amyloid-like fibrils capturing amyloid beta1-42 peptides

Amyloid beta-peptide (Abeta) plays a critical role in Alzheimer's disease (AD). The monomeric state of Abeta can self-assemble into oligomers, protofibrils, and amyloid fibrils. Since the fibrils and soluble oligomers are believed to be responsible for AD, the construction of molecules capable of capturing these species could prove valuable as a means of detecting these potentially toxic species and of providing information pertinent for designing drugs effective against AD. To this aim, we have designed short peptides with various hydrophobicities based on the sequence of Abeta14-23, which is a critical region for amyloid fibril formation. The binding of the designed peptides to Abeta and the amplification of the formation of peptide amyloid-like fibrils coassembled with Abeta are elucidated. A fluorescence assay utilizing thioflavin T, known to bind specifically to amyloid fibrils, revealed that two designed peptides (LF and VF, with the leucine and valine residues, respectively, in the hydrophobic core region) could form amyloid-like fibrils effectively by using mature Abeta1-42 fibrils as nuclei. Peptide LF also coassembled with soluble Abeta oligomers into peptide fibrils. Various analyses, including immunostaining with gold nanoparticles, enzyme-linked immunosorbent assays, and size-exclusion chromatography, confirmed that the LF and VF peptides formed amyloid-like fibrils by capturing and incorporating Abeta1-42 aggregates into their peptide fibrils. In this system, small amounts of mature Abeta1-42 fibrils or soluble oligomers could be transformed into peptide fibrils and detected by amplifying the amyloid-like fibrils with the designed peptides.     

Phosphate-mediated molecular memory driven by two different protein kinases as information input elements

There is increasing interest in studying molecular-based devices that perform Boolean logic operations whose output state (0 or 1) depends on the input conditions (0/0, 1/0, 0/1, or 1/1). So far, great efforts have been devoted to establish molecular-scaled logic gates activated by chemical, physical, and biological inputs. We herein describe the design and synthesis of a tandem protein kinase substrate peptide acting as a phosphate-mediated molecular memory. The molecular-based memory system is comprised of two different phosphorylatable substrate regions joined in series and a spiropyran derivative at the N-terminus. We also demonstrated three basic "AND", "OR", and "NOR" logic operations on the basis of alterations in the spiropyran-to-merocyanine (SP-to-MC) thermocoloration properties of the spiropyran moiety in the peptide upon kinase-catalyzed phosphorylation. The three logic functions were successfully performed by adding ionic polymers as programming elements with preset thresholds of a signal intensity in a microplate format. Throughout this study, information was recorded on the substrate peptide by protein kinase-catalyzed phosphorylation, stored stably as phosphoesters, read according to the extent of the SP-to-MC thermocoloration, and erased by phosphatase-catalyzed dephosphorylation, resulting in the peptide returning to the initial recordable state. Thus, the proof-of-concept experiments described herein could be used to provide clues for developing practical molecular-based processing and computing.