Computer-generated hologram fabricated by electron-beam lithography for noise reduction

A Lohmann-type computer-generated hologram (CGH) is fabricated using an electron-beam lithographic system. A high-resolution groove width of 0.2 μm is attained in relief gratings by changing the e-beam exposures. A diffraction efficiency close to ∼30.4% is obtained by using resist-on-silicon recording materials and cell-structural apertures in a CGH. The reconstructed images exhibit fewer phase noises owing to the incorporation of a non-overflow cell structure into a CGH. The CGH is designed for reconstruction-noise reduction by using an iterative error-reduction algorithm. The designed CGH exhibits fewer reconstruction noises such that the performance function in the convergence is smaller by a factor of 1/3 than that in the first iteration. Experiments demonstrating the performance of CGHs obtained by electron-beam lithography are presented.     

Ultrasound activates ataxia telangiectasia mutated- and rad3-related (ATR)-checkpoint kinase 1 (Chk1) pathway in human leukemia Jurkat cells

Low-intensity ultrasound (US) has been shown to induce death of cancer cells; however, the underlying mechanism remains unclarified. Here, we provide novel evidence that the inhibition of checkpoint kinase 1 (Chk1) by a selective inhibitor or small interfering RNA (siRNA) enhances US-induced apoptosis in Jurkat cells. Jurkat cells showed insignificant lysis immediately after US at any applied intensity, whereas approximately 70% of the cells were γH2AX-positive 30min after US at 0.4W/cm(2). Regarding DNA damage response (DDR), Chk1, known as a target of ataxia telangiectasia mutated (ATM) and rad3-related (ATR), was phosphorylated in cells after US exposure. An ATM inhibitor showed nearly no effect on Chk1 phosphorylation, whereas chemicals showing the ATR inhibitory effect markedly abrogated the phosphorylation, indicating that Chk1 phosphorylation is preferentially more dependent on ATR than on ATM in cells exposed to US. The pharmacological inhibition of Chk1 promoted caspase-3 cleavage and increased the percentage of cells in SubG1 after US exposure. siRNA targeting Chk1 abrogated approximately 55% of Chk1 expression and also promoted apoptosis, suggesting that Chk1 plays anti-apoptotic roles in response to US. These findings revealed, for the first time, that US activates Chk1 dependently on ATR and the activated Chk1 is involved in apoptosis of cells exposed to US. Moreover, we propose that Chk1 may be a promising target in US-aided therapy.     

NAD(P)+–NAD(P)H models. 84. Stereochemistry controlled by the electronic effect from a sulfinyl group

2,3-Dihydro-2,2,4-trimethylthieno[3,2-b]pyridinium 1-oxide iodide ( 1 ) has been reacted with various inorganic and organic hydride donors. It has been found that the stereochemistry of reaction is controlled by the orientation of the sulfinyl dipole, and the relative bulkiness of substituents plays no role in determining the reaction face: a reactive hydride donor prefers to attack at the anti-face with respect to the sulfinyl dipole, whereas a less reactive hydride donor prefers to attack at the syn-face.     

In situ Raman and optical microscopy of the relaxation behavior of amorphous ices under pressure

The transformation of low‐density amorphous (LDA) ice produced from high‐density amorphous (HDA) ice was studied up to 400 MPa as a function of temperature by in situ Raman spectroscopy and optical microscopy. Changes in these amorphous states of H₂O were directly tracked without using emulsions to just above the crystallization temperature T_x. The spectra show significant changes occurring above ∼125 K. The results are compared with data reported for the relaxation behavior of HDA, to form what we call relaxed HDA, or rHDA. We find a close connection with expanded HDA (eHDA), which is reported to exist as another metastable form in this P–T region. The observation of this temperature‐induced LDA transition under pressure complements the previously observed pressure‐induced reversible transition between LDA and HDA at 120–140 K. Copyright © 2009 John Wiley & Sons, Ltd.     

A Significant Two-Dimensional Structural Transformation in a Coordination Polymer that Changes Its Electronic and Protonic Behavior

A 2D-to-2D (2D: two-dimensional) structural transformation accompanying significant bond rearrangement and coordination environment change is demonstrated in a coordination polymer (CP) comprised of copper(II) ions and terephthalate (BDC²⁻) ligands for the first time. When immersed in water, a free-standing membrane of 2D Cu(BDC)(DMF) ( Cu-1 ; DMF: N,N-dimethylformamide) transforms into 2D Cu(BDC)(H₂O)₂ ( Cu-2 ) while maintaining its highly oriented layered structure. In the 2D sheet, paddlewheel-type Cu^II dimers coordinated with four bidentate BDC ligands in a square-planar array in Cu-1 were released to form uniform aqua-bridged Cu^II chains, which are cross-linked with each other by unidentate BDC ligands, in Cu-2 . The present facile approach to implement the 2D-to-2D transformation accompanied by bond rearrangement, which is characteristic of CPs, leads to a marked increase in in-plane magnetic susceptibility and proton conductivity. In situ experiments in support of theoretical calculations unveiled the energy diagram that governs the unique structural transformation.     

Self-modeling curve resolution analysis of on-line vibrational spectra of polymerisation and transesterification

This article discusses the potential of self-modeling curve resolution analysis (SMCR) for the evolution of on-line vibrational spectral data of polymerisation and transesterification. After the general introduction of the SMCR approach, representative SMCR techniques like orthogonal projection analysis (OPA) and simple-to-use interactive self-modeling mixture analysis (SIMPLISMA) are briefly outlined. As examples the SMCR analysis of the Raman spectra of the block copolymerisation of styrene and 1,3-butadiene and that of the near-infrared (NIR) spectra of the melt-extrusion transesterification of ethylene-vinylacetate copolymer will be illustrated. In the last part of this review paper, a new powerful SMCR method that we have recently proposed is demonstrated.     

The enzymatic degradation of commercial biodegradable polymers by some lipases and chemical degradation of them

Biodegradable polyesters, poly(butylene succinate adipate) (PBSA), poly(butylene succinate) (PBS), poly(ethylene succinate) (PES), poly(butylene succinate)/poly(caprolactone) blend (HB02B) and poly(butylene adipate terephthalate) (PBAT), were evaluated about degradability for enzymatic degradation by lipases and chemical degradation in sodium hydroxide solution. In enzymatic degradation, PBSA was the most degradable by lipase PS, on the other hand, PBAT containing aromatic ring was little degraded by eleven kinds of lipases. In 1N NaOH solution, degradation rate of PES with ethylene unit was extremely fast, in comparison with other polyesters. Interestingly the degradation rate of PBSA in enzymatic degradation by lipase PS was faster than in chemical degradation.     

Biodegradable ultra high strength poly(L-lactide) rods for bone fixation

The hydrostatic molecular orientation technique was used to explore the highest mechanical improvements achievable for poly-L-lactide (PLLA). The mechanical attributes of these materials designed for bone fracture fixation devices, i.e. bending strength and modulus were measured and compared with those prepared by stretching method. The starting samples were prepared by conventional melt extrusion at 200 °C followed by hydrostatic extrusion at 140 °C using glycerin filled extruder. Uniaxially stretched rods were prepared by drawing in silicon oil at 120 °C. The physical properties of these rods are inadequate as mechanical supports in the dynamic healing process of the bone. Moreover, they underwent a marked strength deterioration when immersed in aqueous buffered solution for 90 days. On the other hand, the hydrostatic extrusion technique produced rods with progressively higher bending strength that showed only a small drop after 90 days hydrolytic degradation. Micrographs suggested a superior molecular orientation and packing, which could be associated with the improved performance. The hydrostatic extrusion technique proved to be a safe and effective approach for strengthening biodegradable polymeric materials for dynamic mechanical support in orthopedic medical devices.     

Selective SERS detection of each polycyclic aromatic hydrocarbon (PAH) in a mixture of five kinds of PAHs

This paper reports the qualitative analysis and quantitative detection of polycyclic aromatic hydrocarbon (PAH) molecules with per‐6‐deoxy‐(6‐thio)‐β‐cyclodextrin (CD‐SH) modified gold nanoparticles (AuNPs) by surface‐enhanced Raman scattering (SERS) spectroscopy. For the selective sensing of PAHs, which are environmental pollutants with very low affinity to metallic surfaces, by SERS, a stable substrate with AuNPs and CD‐SH was utilized by supramolecular interaction. Quantitative detection of each PAH was carried out by SERS on inclusion complexes with different concentrations. From the SERS spectra of a mixture of five different PAHs, we could easily distinguish each PAH by its discriminant peaks. In addition, quantitative analysis of one component in a mixture of five PAHs was also investigated. This sensing platform revealed matching relationship between the host and the guest and the host–guest interaction mechanism. The proposed approach for the selective detection of PAHs holds great potential in the detection of environmental organic pollutants. Copyright © 2010 John Wiley & Sons, Ltd.     

Fourier‐Transform Raman Spectroscopic On‐Line Monitoring of the Anionic Dispersion Block Copolymerization of Styrene and 1,3‐Butadiene

The anionic dispersion block copolymerization of styrene and 1,3‐butadiene has proved a suitable technique to synthesize block copolymers of tailor‐made blocklength under technically relevant conditions. For this purpose, however, an efficient analytical on‐line technique is required to control the concentrations of individual reactants and product. The present communication shortly outlines the potential of non‐invasive light‐fiber Fourier‐transform Raman spectroscopy in combination with a self‐modeling curve‐resolution analysis to monitor the polymerization progress and to derive concentration profiles of the two monomers and polybutadiene without prior calibration of the investigated system.