Two New Cytotoxic Spirostane‐Steroidal Saponins from the Roots of Bletilla striata

Two new spirostane‐steroidal saponins, bletilnoside A ( 1 ) and bletilnoside B ( 2 ), together with five known compounds, 3 – 7 , were isolated from the roots of Bletilla striata (Thunb .) Reichb . F. The structures of the new compounds were determined based on their 1D‐ and 2D‐NMR spectral data. The isolated compounds 1 – 7 were tested for cytotoxicity against four human tumor cells (A549, SK‐OV‐3, SK‐MEL‐2, and HCT15) in vitro using a sulforhodamin B bioassay, and compounds 1, 2 , and 5 showed significant cytotoxicities against all tested tumor cell lines with IC₅₀ values ranging from 3.98±0.16 to 12.10±0.40 μM .     

Multi-class classification using a signomial function

We propose two multi-class classification methods using a signomial function. Each of these methods directly constructs a multi-class classifier by solving a single optimization problem. Since the number of possible signomial terms is extremely large, we propose a column generation method that iteratively generates good signomial terms. Both of these methods obtain better or comparable classification accuracies than existing methods and also provide more sparse classifiers.     

Facile preparation of recyclable biocatalyst-decorated magnetic nanobeads in aqueous media

A facile process was developed to manufacture biocatalyst-conjugated magnetic nanobeads, which afford no loss of the intrinsic activity and enantioselectivity of biocatalysts. Up to 90% of their activities remained after six-time recycling in aqueous media.     

Development of a method for nuclide leaching from glass fiber in HEPA filter

For the disposal of the high efficiency particulate air (HEPA) glass filter to environment, the glass fiber should be leached to lower its radioactive concentration. To derive the optimum method for removal of Co and Cs from HEPA glass fiber, four methods were applied in this study. Results of electrochemical leaching of glass fiber by 4.0 M HNO₃–0.1 M Ce(IV) solution showed that the removal efficiency of ¹³⁴Cs, ¹³⁷Cs, and ⁶⁰Cs from glass fiber after 5 h was 96.4, 93.6, and 93.8%, respectively. Results by 5 wt% NaOH solution showed that the removal efficiency of ¹³⁴Cs, ¹³⁷Cs, and ⁶⁰Cs after 30 h was 81.7, 82.1, and 10.0%, respectively. Results by repeat 2.0 M HNO₃ solution showed that the removal efficiencies of ¹³⁴Cs, ¹³⁷Cs, and ⁶⁰Cs after 2 h of three repetitions were 96.2, 99.4, and 99.1%, respectively. Finally, results by repeat 4.0 M HNO₃ solution showed that the removal efficiencies of ¹³⁴Cs, ¹³⁷Cs, and ⁶⁰Cs after 4 h of three repetitions were 100, 99.9, and 99.9%, respectively, and their radioactivities were below 0.1 Bq/g. Therefore, the chemical leaching method by 4.0 M HNO₃ solution was considered as an optimum one for removal of cesium and cobalt from HEPA glass fiber for self disposal. Also the removal efficiencies of ⁶⁰Co, ¹³⁴Cs, and ¹³⁷Cs from the waste-solution after its precipitation-filtration treatment for reuse of 4.0 M HNO₃ waste-solution were 88.0, 95.0, and 99.8%.     

Analysis of the HDO content in heavy water by ATR-FTIR

The applicability of ATR-FTIR for the determination of the HDO content in heavy water (D₂O) was investigated. Two groups of calibration standard solutions, of low contents (0–1 n% H₂O in heavy water) and of higher contents (0–10 n% H₂O in heavy water) were prepared by adding properly calculated amount of H₂O to D₂O by weight. The absorbances at 3400 cm⁻¹ (ν, O–H) against the calibration standards were measured five times using two kinds of interchangeable IREs (1 bound and 9 bound reflections). And four calibration curves were obtained by linear least square fit of the measured absorbances for the four different measurement conditions, which are (1) for low contents group using 1 bound reflection, (2) for low contents group using 9 bound reflections, (3) for higher contents group using 1 bound reflection, (4) for higher contents group using 9 bound reflections. Determined contents (c ₀) of each calibration standards for the four measurement conditions were obtained by the calibration curves and compared to the calculated contents (c _cal). The uncertainty sources were considered when the HDO in heavy water is determined according to the procedure of this work. The uncertainties u(c ₀) of the determined contents (c ₀) for the four different measurement conditions were calculated.     

Enhancement of surface wettability via the modification of microtextured titanium implant surfaces with polyelectrolytes

Micrometer- and submicrometer-scale surface roughness enhances osteoblast differentiation on titanium (Ti) substrates and increases bone-to-implant contact in vivo. However, the low surface wettability induced by surface roughness can retard initial interactions with the physiological environment. We examined chemical modifications of Ti surfaces [pretreated (PT), R(a) ≤ 0.3 μm; sand blasted/acid etched (SLA), R(a) ≥ 3.0 μm] in order to modify surface hydrophilicity. We designed coating layers of polyelectrolytes that did not alter the surface microstructure but increased surface ionic character, including chitosan (CHI), poly(L-glutamic acid) (PGA), and poly(L-lysine) (PLL). Ti disks were cleaned and sterilized. Surface chemical composition, roughness, wettability, and morphology of surfaces before and after polyelectrolyte coating were examined by X-ray photoelectron spectroscopy (XPS), contact mode profilometry, contact angle measurement, and scanning electron microscopy (SEM). High-resolution XPS spectra data validated the formation of polyelectrolyte layers on top of the Ti surface. The surface coverage of the polyelectrolyte adsorbed on Ti surfaces was evaluated with the pertinent SEM images and XPS peak intensity as a function of polyelectrolyte adsorption time on the Ti surface. PLL was coated in a uniform thin layer on the PT surface. CHI and PGA were coated evenly on PT, albeit in an incomplete monolayer. CHI, PGA, and PLL were coated on the SLA surface with complete coverage. The selected polyelectrolytes enhanced surface wettability without modifying surface roughness. These chemically modified surfaces on implant devices can contribute to the enhancement of osteoblast differentiation.