The development of a portable line-shaping optical system for silicon surface treatment

This study proposes a beam shaper for converting a circle beam profile generated with a Gaussian intensity distribution by an 808 nm diode laser into a line beam profile for silicon surface treatment applications. To produce a hand-held and low-cost device with a large spot-size laser, this study uses a portable optical system consisting of a diode laser source, a collimator, a cylindrical lens, and a plano-convex lens to generate an approximately 40 × 3:5mm² line beam profile at a working distance of 200 mm. The silicon surface treated by the line-shaped laser beam has significantly reduced reflectance spectra. The proposed system is also suitable for the surface cleaning of materials.     

Formation and characterization of mixed polyelectrolyte–surfactant Langmuir layer templates for silver nanoparticle growth

The hydrophilic characteristic of the polyelectrolyte, poly(4-styrenesulfonic acid) (PSS), was modified by associating with the surfactant, dodecyltrimethylammonium bromide (DTMAB), to form polyelectrolyte–surfactant (PSS–DTMA) Langmuir layers at air/liquid interfaces. The interfacial behavior of the PSS–DTMA complexes was investigated with the Langmuir trough technique. The mixed PSS–DTMA Langmuir layers were then used as the two-dimensional templates to incorporate with silver precursors from the subphase, and were transferred onto mica substrates with the Langmuir–Blodgett (LB) deposition technique. The silver nanoparticles were fabricated in the resulting LB films with UV irradiation, and the morphology of the silver nanoparticle structures was analyzed by atomic force microscopy (AFM). The results indicated that increasing the DTMA⁺ content in the mixed PSS–DTMA system would enhance the hydrophobic characteristic of the complexes and then form stable PSS–DTMA Langmuir layers at interfaces. In addition, by varying the DTMA⁺ content, one could adjust the charge density in the Langmuir layer templates and thus control the association behavior between the two-dimensional templates and the silver precursors in the subphases. The AFM images demonstrated that the formation of the silver nanoparticle structures in the UV-treated LB films could be regulated with the DTMA⁺ content in the Langmuir layer templates. It is inferred that the polyelectrolyte–surfactant template offers a potential of designing structures of polyelectrolyte–nanoparticle materials with a template-synthesis procedure.     

One‐ and Two‐Component Bottle‐Brush Polymers: Simulations Compared to Theoretical Predictions

Scaling predictions for bottle‐brush polymers with a rigid backbone and flexible side chains under good solvent conditions are discussed and their validity is assessed by a comparison with Monte Carlo simulations of a simple lattice model. It is shown that typically only a rather weak stretching of the side chains is realized, and then the scaling predictions are not applicable. Also two‐component bottle brush polymers are considered, where two types (A,B) of side chains are grafted, assuming that monomers of different kind repel each other. In this case, variable solvent quality is allowed. Theories predict “Janus cylinder”‐type phase separation along the backbone in this case. The Monte Carlo simulations, using the pruned‐enriched Rosenbluth method (PERM) give evidence that the phase separation between an A‐rich part of the cylindrical molecule and a B‐rich part can only occur locally. The correlation length of this microphase separation can be controlled by the solvent quality. This lack of a phase transition is interpreted by an analogy with models for ferromagnets in one space dimension.

     

Synthesis and Characterization of Cationic Glycidyl-Based Poly(aminoester)-Folic Acid Targeting Conjugates and Study on Gene Delivery

A new poly(aminoester) (EPAE-FA) containing folic acid and amino groups in the backbone and side chain was synthesized. EPAE-FA self-assembled readily with the plasmid DNA (pCMV-βgal) in HEPES buffer and was characterized by dynamic light scattering, zeta potential, fluorescence images, and XTT cell viability assays. To evaluate the transfection effect of graft ratio of FA on the EPAE system, EPAE-FA polymers with two different graft ratios (EPAE-FA12k and EPAE-FA14k) were also prepared. This study found that all EPAE-FA polymers were able to bind plasmid DNA and yielded positively charged complexes with nano-sized particles ( < 200 nm). To assess the transfection efficiency mediated by EPAE and EPAE-FA polymers, we performed in vitro transfection activity assays using FR-negative (COS-7) and FR-positive (HeLa) cells. The EPAE-FA12k/DNA and EPAE-FA14k/DNA complexes were able to transfect HeLa cell in vitro with higher transfection efficiency than PEI25k/DNA at the similar weight ratio. These results demonstrated that the introduction of FA into EPAE system had a significant effect on transferring ability for FR-positive cells (HeLa). Examination of the cytotoxicity of PEI25k and EPAE-FA system revealed that EPAE-FA system had lower cytotoxicity. In this paper, EPAE-FA seemed to be a novel cationic poly(aminoester) for gene delivery and an interesting candidate for further study.     

Ruthenium-catalyzed oxidation of a carbon-carbon triple bond: facile syntheses of alkenyl 1,2-diketones from alkynes

A new oxidation procedure of alkynes catalyzed by Tp(PPh(3))(CH(3)CN)Ru-Cl is presented, which provides an efficient way to obtain alkenyl 1,2-diketones via ruthenium alkenyl 1,2-diketone intermediates. In contrast, the analogous reactions with Tp(PPh(3))(PhCN)Ru-Cl gave rise to the ruthenium metallacycle complexes.     

High-throughput 3D spheroid culture and drug testing using a 384 hanging drop array

Culture of cells as three-dimensional (3D) aggregates can enhance in vitro tests for basic biological research as well as for therapeutics development. Such 3D culture models, however, are often more complicated, cumbersome, and expensive than two-dimensional (2D) cultures. This paper describes a 384-well format hanging drop culture plate that makes spheroid formation, culture, and subsequent drug testing on the obtained 3D cellular constructs as straightforward to perform and adapt to existing high-throughput screening (HTS) instruments as conventional 2D cultures. Using this platform, we show that drugs with different modes of action produce distinct responses in the physiological 3D cell spheroids compared to conventional 2D cell monolayers. Specifically, the anticancer drug 5-fluorouracil (5-FU) has higher anti-proliferative effects on 2D cultures whereas the hypoxia activated drug commonly referred to as tirapazamine (TPZ) are more effective against 3D cultures. The multiplexed 3D hanging drop culture and testing plate provides an efficient way to obtain biological insights that are often lost in 2D platforms.     

Simultaneous determination of uric acid and creatinine in urine by an eco-friendly solvent-free high performance liquid chromatographic method

A simple, rapid, and eco-friendly analytical method for simultaneous determination of uric acid and creatinine in urine applying high performance liquid chromatography (HPLC) is described. After dilution, de-protein, and filtration, the sample solution was injected to separate the species with C-18 column by an eluent containing 0.05 M ammonium phosphate buffer at pH 7.4. An UV detector was used to monitor the separation of species at 235 nm. Optimum conditions for separation and detection were investigated. Results indicated that under optimized condition measurements were achieved within 13 min. The detection limits were 0.127 and 0.156 mug ml(-1) for uric acid and creatinine respectively. The recovery was 95% (0.57% RSD) for uric acid and 99.2% (0.98% RSD) for creatinine, from five measurements. Real urine specimens were tested.     

Zirconium complexes containing a diarylamido diphosphine ligand: Structural preferences controlled by ligand electronics and sterics

This work describes the preparation of [PNP]ZrX₃ ([PNP]⁻ = [N(o-C₆H₄PⁱPr₂)₂]⁻; X = Cl, Me, CH₂SiMe₃) whose structural preference is found to be a function of the electronic and steric nature of the monodentate ligand X⁻. The reaction of ZrCl₄(THF)₂ with [PNP]Li in toluene at room temperature generates [PNP]ZrCl₃ as a red solid in 60% yield. Alkylation of [PNP]ZrCl₃ with three equivalents of Grignard reagents in diethyl ether at −35 °C produces cleanly [PNP]ZrR₃ (R = Me, CH₂SiMe₃) as yellow crystalline materials. An X-ray diffraction study of [PNP]ZrCl₃ showed it to be a chloride-bridged binuclear species {[PNP]ZrCl₂(μ−Cl)}₂ in which both zirconium atoms are 7-coordinate whereas that of [PNP]ZrMe₃ revealed a mononuclear, 6-coordinate core structure. Interestingly, with the incorporation of more sterically demanding alkyls, [PNP]Zr(CH₂SiMe₃)₃ is a 5-coordinate compound wherein the amido phosphine ligand is κ²-N,P bound to zirconium. The solution structures of these molecules were also assessed by variable-temperature NMR spectroscopy.     

Spectrophotometric determination of deacetylation degree of chitinous materials dissolved in phosphoric acid

A simple spectrophotometric method is proposed for determining deacetylation degrees (DD) of chitinous materials using phosphoric acid as the UV-transparent solvent system. Calibrating by the extinction coefficients (A(210)) of D-glucosamine and N-acetyl-D-glucosamine, DD values (24-88%) were computed numerically. The results correlated well (R(2) = 0.9805, n = 50) with those obtained by solid-state (13)C NMR. Comparison of the results obtained by the proposed UV method and solid-state (13)C NMR.     

Cytotoxic phenylpropanoids and a new triterpene, turformosinic acid, from Turpinia formosana Nakai

One new phenylpropanoid, turformosin A (1), and one new triterpene, turformosinic acid (2), together with 16 known compounds, were isolated from the stems of Turpinia formosana Nakai. All structures were elucidated on the basis of spectroscopic analysis, including 1D- and 2D-NMR techniques and MS analysis. Selected isolated compounds were evaluated for in vitro cytotoxicity against four human cancer cell lines and antioxidant scavenging effects on DPPH. (-)-(7'S,8'S)-threo-carolignan X (3) exhibited cytotoxicity against Hep2, WiDr, Daoy, and MCF-7 cell lines with ED(50) values of 3.60, 4.45, 6.07, and 13.7 μg/mL, respectively. Turformosin A (1), (-)-(7'S,8'S)- threo-carolignan X (3), methoxyhydroquinone-4-β-D-glucopyranoside (5), and methoxy-hydroquinone-1-β-D-glucopyranoside (6), exhibited similar anti-oxidative activity. Hep2 cells treated with 10 μg/mL of 3 showed elevation of sub-G1 population (from 20% at 8 h to 60% at 48 h), and activation of caspase-9/caspase-3/PARP cascade. Compound 3 induced intrinsic apoptotic pathway in Hep2 cells with dose and time dependence (10 μg/mL for 8 h).