2′,4′-BNA/LNA with 9-(2-Aminoethoxy)-1,3-diaza-2-oxophenoxazine Efficiently Forms Duplexes and Has Enhanced Enzymatic Resistance**

Artificial nucleic acids are widely used in various technologies, such as nucleic acid therapeutics and DNA nanotechnologies requiring excellent duplex-forming abilities and enhanced nuclease resistance. 2′-O,4′-C-Methylene-bridged nucleic acid/locked nucleic acid (2′,4′-BNA/LNA) with 1,3-diaza-2-oxophenoxazine (BNAP ( B^H )) was previously reported. Herein, a novel B^H analogue, 2′,4′-BNA/LNA with 9-(2-aminoethoxy)-1,3-diaza-2-oxophenoxazine (G-clamp), named BNAP-AEO ( B^AEO ), was designed. The B^AEO nucleoside was successfully synthesized and incorporated into oligodeoxynucleotides (ODNs). ODNs containing B^AEO possessed up to 10⁴-, 152-, and 11-fold higher binding affinities for complementary (c) RNA than those of ODNs containing 2′-deoxycytidine ( C ), 2′,4′-BNA/LNA with 5-methylcytosine ( L ), or 2′-deoxyribonucleoside with G-clamp ( P^AEO ), respectively. Moreover, duplexes formed by ODN bearing B^AEO with cDNA and cRNA were thermally stable, even under molecular crowding conditions induced by the addition of polyethylene glycol. Furthermore, ODN bearing B^AEO was more resistant to 3′-exonuclease than ODNs with phosphorothioate linkages.     

Water revealed as molecular mirror when measuring low concentrations of sugar with near infrared light

Near infrared spectroscopy is an overtone spectroscopy regarded as a quick and non-destructive method that provides analytical solutions for components that represent approximately 1% or more of the total mass of the investigated composite samples. Aquaphotomics offers the possibility for disentanglement of information remaining hidden in the spectra when conventional data evaluation methods are used, since this concept utilizes changes of the water structure induced by the measured solute as specific molecular vibrations at water bands. Here, near infrared technique and aquaphotomics are applied for non-destructive identification and quantification of mono- and di-saccharide solutes at 100–0.02 mM concentration that is accepted as unachievable with near infrared spectroscopy. The results presented in this study support the aquaphotomics' water molecular mirror concept that explores spectral changes related to water molecular rearrangements caused by minute changes of the solutes in the aqueous systems. The method provides quick and accurate alternative for classical analytical measurements of saccharides even at millimolar concentration levels.     

α- and γ-Regiocontrol and Enantiospecificity in the Copper-Catalyzed Substitution Reaction of Propargylic Phosphates with Grignard Reagents

The regioselectivity (r.s.) and enantiospecificity (e.s.) of the substitution reactions of secondary propargylic alcohol derivatives using reagents derived from ArMgBr and Cu salts were studied. First, the picolinate, 3-methylpicolinate, and diethylphosphonate derivatives of Ph(CH₂)₂CH(OH)C≡CTMS were reacted with PhMgBr/CuCN in ratios of 2.5:2.7–2.5:0.25. The use of 2.5:0.25 ratio in THF/DME (6:1) at 0 °C for 1 h afforded the α-substitution product from the phosphate with ≥98 % r.s. and 99 % e.s. CuBr⋅Me₂S gave similar selectivity. The reaction system was then applied to phosphates derived from R¹CH(OH)C≡CR² and ArMgBr to obtain synthetically sufficient r.s. and e.s. values with R²=TMS, Ph, whereas iPr was borderline in terms of size as an R¹ substituent. The presence of a substituent at the o-position of Ar marginally affected the selectivity. We also found that the use of PhMgBr/Cu(acac)₂ in a 2:1 ratio in THF produced the γ-substitution products (allenes) with high r.s. and e.s.     

Synthesis and toxicity assay of ceramic nanophosphors for bioimaging with near-infrared excitation

Yttrium hydroxyl carbonate (Y(OH)CO₃) precursors were synthesized by the homogeneous co-precipitation method in the presence of polyacrylic acid (PAAc). Resultant precursor particle size is about 15–20 nm with narrow size distribution whereas the particle size is smaller than those acquired by the conventional homogeneous precipitation method. Effective decrease of Y(OH)CO₃ particle size was found to be higher for the presence of weak polyanionic ionomer such as PAAc than the presence of strong polyanionic ionomer such as sodium polystyrene sulfonate (PSS). It was observed that the morphology and size of the precursors are almost unchanged after the calcination process. Er³⁺ doped Y₂O₃ nanoparticles were synthesized by PAAc assisted homogeneous co-precipitation method showed bright green (550 nm) and red (660 nm) upconversion (UC) as well as near-infrared (NIR) fluorescence (1550 nm) under 980-nm excitation. UC and NIR fluorescence bioimaging and in-vitro cytotoxicity assay of Er³⁺ doped Y₂O₃ nanoparticles were successfully attempted with commercially available macrophages and B-cell hybridomas. Cellular uptake of nanoparticles is evidenced from bright field, UC and NIR fluorescence images of macrophages.     

Efficient Synthesis of Polycyclic γ-Lactams by Catalytic Carbonylation of Ene-Imines via Nickelacycle Intermediates

The nickel(0)-catalyzed carbonylative cycloaddition of 1,5- and 1,6-ene-imines with carbon monoxide (CO) is reported. Key to this reaction is the efficient regeneration of the catalytically active nickel(0) species from nickel carbonyl complexes such as [Ni(CO)₃L]. A variety of tri- and tetracyclic γ-lactams were thus prepared in excellent yields with 100 % atom efficiency. Preliminary results on asymmetric derivatives promise potential in the synthesis of enantioenriched polycyclic γ-lactams.     

Three lanostane triterpenoids with antitrypanosomal activity from the fruiting body of Hexagonia tenuis

During the search for new antitrypanosomal drug leads, three new antitrypanosomal compounds, hexatenuins A–C (1–3), were isolated from the fruiting body of Hexagonia tenuis. 1 and 3 possessed an unusual malonate half-ester functional group at C-3 position, and 1 and 2 had a spirostructure in the side-chain. Their structures were elucidated using MS analyses, extensive 2D-heteronuclear NMR data interpretation. Compounds 1–3 showed in vitro antitrypanosomal activity against Trypanosoma brucei brucei with IC₅₀ values of 0.57, 8.60 and 5.62 μg/ml, respectively.     

Interaction of Short Laser Pulses in Wavelength Range from Infrared to X‐ray with Metals,Semiconductors, and Dielectrics

Laser‐matter interaction is defined by an electronic band structure of condensed matter and frequency ω_L of electromagnetic radiation. In the range of moderate fluences, the energy absorbed by electrons from radiation finally thermalizes in the ion thermal energy. The thermalization processes are different for optical as compared with X‐ray quanta and for metals relative to semiconductors and dielectrics, since the light absorption and electron‐electron, electron‐ion dynamics are sensitive to the electron population in a conduction band and the width of a forbidden gap. Although the thermalization processes are different, the final state is simply a heated matter. Laser heating creates powerful stresses in a target if duration of a laser pulse τ_L is short in acoustic time scale. Nucleation and material removal take place under such stresses. Such way of removal is called here the spallative ablation. Thus the spallative ablation is an ablation mechanism universally important for qualitatively different materials and quanta (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Commutativity in special unitary groups at odd primes

It is a classical result by Bott that SU(s) and SU(t) homotopy commute in SU(n) if and only if s+t?n. We consider the p-localization analog of this problem and give an answer at odd primes.     

In-flight (K~-,N) Reactions for Study of Kaon-nucleus Interaction

We would like to emphasize that the in-flight (K~-,N) reactions are particularly useful for the study of the K-nucleus interaction.Since the reaction mechanism is well known,there is little ambiguity to derive the K-nucleus interaction from the measured missing mass spectra.Here we discuss the missing mass spectra of the (K~-,N) reactions on the ~(12)C and ~(16)O targets.The spectra show an appreciable amount of strength below the K-nucleus threshold which indicates that the K-nuclear potential is strongly attractive.Comparison of the missing mass spectra with theoretical calculations leads to a potential depth of around-190 MeV for the ~(12)C(K~-,n) reaction.A less deep potential of around-160 MeV reproduces well that of the ~(12)C(K~-,p) reaction.The difference can be due to isospin dependence of the interaction.Our data show that the K-nucleus potential is very deep to realize kaon condensation in the core of neutron stars.