Environmental factors relating to arsenic accumulation by Dunaliella sp

The accumulation of arsenic by Dunaliella sp. was examined by using a solution containing arsenic only as a first approach to the study of arsenic recovery by aqueous systems. The accumulation of arsenic by Dunaliella sp. was rapid, with equilibrium established in 8 h with respect to arsenic partioning between dissolved and particulate phase. The optimum accumulation was at pH 8.2, NaCl 20 g dm^?3, illumination 5000–10000 lux and temperature 22°C. Increased phosphate concentration significantly decreased the uptake of arsenic in the culture. These results suggested that accumulation of arsenic by Dunaliella sp. depended upon biological activity.     

Studies on the biological activity of tocotrienols

Tocotrienols were evaluated for activity against transplantable murine tumors inoculated i.p. into mouse, and the activities of two tocotrienols and alpha-tocopherols were compared. When the compounds were injected i.p., alpha- and gamma-tocotrienols were effective against sarcoma 180, Ehrlich carcinoma, and IMC carcinoma, and gamma-tocotrienol showed a slight life-prolonging effect in mice with Meth A fibrosarcoma, but the tocotrienols had no antitumor activity against P388 leukemia at doses of 5-40 mg/kg/d. On the other hand alpha-tocopherol had only a slight effect against sarcoma 180 and IMC carcinoma. The antitumor activity of gamma-tocotrienol was higher than that of alpha-tocotrienol. Tocotrienols showed growth inhibition of human and mouse tumor cells when the cells were exposed to these agents for 72 h in vitro, whereas tocopherol did not show any marked cytotoxic activity. Alpha- and gamma-tocotrienols had inhibitory effects on lipid peroxidation of murine microsomes by adriamycin.     

Synthesis of bhimamycin B based on oxidative rearrangement of 4-acetylnaphtho[1,2-b]furan-5-ol to naphtho[2,3-c]furan-4,9-dione

The first total synthesis of bhimamycin B, a novel member of naphtho[2,3-c]furan quinone antibiotics, was achieved by oxidative skeletal rearrangement of 4-acetylnaphtho[1,2-b]furan-5-ol.     

Replica multichannel polymer chips with a network of sacrificial channels sealed by adhesive printing method

Replica microchips for capillary array electrophoresis containing 10 separation channels (50 microm width, 50 microm depth and 100 microm pitch) and a network of sacrificial channels (100 microm width and 50 microm depth) were successfully fabricated on a poly(methyl methacrylate) (PMMA) substrate by injection molding. The strategy involved development of moving mask deep X-ray lithography to fabricate an array of channels with inclined channel sidewalls. A slight inclination of channel sidewalls, which can not be fabricated by conventional deep X-ray lithography, is highly required to ensure the release of replicated polymer chips from a mold. Moreover, the sealing of molded PMMA multichannel chips with a PMMA cover film was achieved by a novel bonding technique involving adhesive printing and a network of sacrificial channels. An adhesive printing process enables us to precisely control the thickness of an adhesive layer, and a network of sacrificial channels makes it possible to remove air bubbles and an excess adhesive, which are crucial to achieving perfect sealing of replica PMMA chips with well-defined channel and injection structures. A CCD camera equipped with an image intensifier was used to simultaneously monitor electrophoretic separations in ten micro-channels with laser-induced fluorescence detection. High-speed and high-throughput separations of a 100 bp DNA ladder and phi X174 Hae III DNA restriction fragments have been demonstrated using a 10-channel PMMA chip. The current work establishes the feasibility of mass production of PMMA multichannel chips at a cost-effective basis.     

Analysis of blood plasma proteins in patients with Alzheimer's disease by two-dimensional electrophoresis, sequence homology and immunodetection

Blood plasma proteins of patients with Alzheimer's disease (AD; senile dementia) and non-AD-type dementia were resolved by two-dimensional electrophoresis and identified by migration position in the electrophoresis pattern, sequence homology, and immunodetection by using antibodies. For the control experiments, blood plasma proteins of a healthy young individual and non-dementia patients were examined in a manner similar to that of the plasma samples of AD patients. In the plasma sample of the healthy young individual, more than 350 spots of silver-stained proteins were observed and among these spots, 73 spots were identified. Blood plasma proteins of the AD and non-AD-type dementia patients were compared with those of the control and non-dementia patients. In the blood plasma samples of five AD patients, three patients had apolipoprotein E4, and another patient showed apolipoprotein L and complement factor H. For the AD-related proteins apolipoprotein E, tau-1, and presenilin 2, proteins were examined by immunostaining with antibodies, in both AD and non-AD patients. Among the three samples of non-AD-type dementia patients, one was distinguishable by amyloid A proteins, and the other by haptoglobin isoforms.     

Synthesis of Glc1Man9‐Glycoprotein Probes by a Misfolding/Enzymatic Glucosylation/Misfolding Sequence

Glycoproteins in non‐native conformations are often toxic to cells and may cause diseases, thus the quality control (QC) system eliminates these unwanted species. Lectin chaperone calreticulin and glucosidase II, both of which recognize the Glc₁Man₉ oligosaccharide on glycoproteins, are important components of the glycoprotein QC system. Reported herein is the preparation of Glc₁Man₉‐glycoproteins in both native and non‐native conformations by using the following sequence: misfolding of chemically synthesized Man₉‐glycoprotein, enzymatic glucosylation, and another misfolding step. By using synthetic glycoprotein probes, calreticulin was found to bind preferentially to a hydrophobic non‐native glycoprotein whereas glucosidase II activity was not affected by glycoprotein conformation. The results demonstrate the ability of chemical synthesis to deliver homogeneous glycoproteins in several non‐native conformations for probing the glycoprotein QC system.     

Heterotactic‐specific radical polymerization of N‐isopropylacrylamide and phase transition behavior of aqueous solution of heterotactic poly(N‐isopropylacrylamide)

Radical polymerization of N‐isopropylacrylamide (NIPAAm) in toluene at low temperatures, in the presence of fluorinated‐alcohols, produced heterotactic polymer comprising an alternating sequence of meso and racemo dyads. The heterotacticity reached 70% in triads when polymerization was carried out at ?40 °C using nonafluoro‐tert‐butanol as the added alcohol. NMR analysis revealed that formation of a 1:1 complex of NIPAAm and fluorinated‐alcohol through C?O···H? O hydrogen bonding induces the heterotactic specificity. A mechanism for the heterotactic‐specific polymerization is proposed. Examination of the phase transition behavior of aqueous solutions of heterotactic poly(NIPAAm) revealed that the hysteresis of the phase transition between the heating and cooling cycles depended on the average length of meso dyads in poly(NIPAAm). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2539–2550, 2009     

Stereospecific radical polymerization of N‐tert‐butoxycarbonylacrylamide in the presence of fluorinated alcohols

Radical polymerization of N‐tert‐butoxycarbonylacrylamide (NBocAAm) in toluene at low temperatures in the presence of the fluorinated alcohols, 2,2,2‐trifluoroethanol, 1,1,1,3,3,3‐hexafluoro‐2‐propanol, and nonafluoro‐tert‐butanol, afforded atactic, heterotactic, and syndiotactic polymers, respectively. NMR analysis revealed that the fluorinated alcohols formed hydrogen bonding‐assisted complexes with NBocAAm, with different structures. The difference in the structures of the complexes was responsible for the differences in the induced stereospecificities. Based on the structures of the complexes between NBocAAm and the fluorinated alcohols, mechanisms for the three kinds of stereospecific radical polymerizations are proposed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Global existence and nonexistence of solutions for second-order nonlinear differential equations

This paper deals with the global existence and nonexistence of solutions of the second-order nonlinear differential equation (φ(x^′))^′+λφ(x)=0${(\phi (x^{\prime }))}^{\prime }+\lambda \phi (x)=0$ satisfying x(0)=_x0$x(0)=x_0$ and x^′(0)=_x1$x^{\prime }(0)=x_1$, where λ   is a positive parameter and φ:(−ρ,ρ)→(−σ,σ)$\phi :(-\rho ,\rho )\to (-\sigma ,\sigma )$ with 0<ρ?∞$0<\rho ?\infty$ and 0<σ?∞$0<\sigma ?\infty$ is strictly increasing odd bijective and continuous on (−ρ,ρ)$(-\rho ,\rho )$. Necessary and sufficient conditions are obtained for the initial value problem to have a unique global solution which is oscillatory and periodic. Examples are given to illustrate our main result. Finally, a nonexistence result for the equation with a damping term is discussed as an application to our result.