ACTION SPECTRA FOR THE GENERATION OF SINGLET OXYGEN FROM MITOCHONDRIAL MEMBRANES FROM SOYBEAN (Glycine max) HYPOCOTYLS

Abstract— The action spectrum for the generation of singlet oxygen (¹O₂) from mitochondrial membranes under aerobic conditions was measured at wavelengths between 360 and 600 nm, using sub-mitochondrial particles (SMP) prepared from soybean hypocotyls. The spectrum, showing a peak at about 420 nm, remarkably resembles the absorption spectra of the Fe-S centers of nonheme iron proteins. Disruption of the Fe-S centers by treating SMP with mersalyl acid resulted in a substantial decrease in the efficiency of ¹O₂ generation, leaving an action spectrum whose pattern is significantly similar to the absorption spectrum of flavins, at least in the region of near UV and blue light wavelengths. Estimating the contribution of the Fe-S centers to the generation of ¹O₂ from SMP, we suggest that the Fe-S centers act as very important endogenous photosensitizers in plant cells, in so far as the type II mechanism is concerned. Possible involvement of mitochondrial flavoproteins in the generation of ¹O₂ is also discussed.     

Facile, alternative synthesis of lanthanum phosphate nanocrystals by ultrasonication

Highly luminescent, rhabdophane (Ce(0.33)La(0.66))PO4.nH2O nanorods and nanoparticles were prepared in aqueous solutions by ultrasonication, at pH 1 and pH 12, respectively. Both nanorods (5 to 9 nm wide and several tens to several hundreds nm long) and nanoparticles (elongated, connected 5 nm particles) were as small and as uniform as products obtained from methods that utilize complexing agents or surfactants, only with no complexing agent. This method of synthesis by ultrasonication is a fast and simple method and it is expected to be applicable for the synthesis of other nanocrystalline lanthanide phosphates.     

Structural and luminescence properties of [Ln(ODA)(phen)·4H2O] complexes (Ln=Sm and Dy, ODA=oxydiacetate, phen=1,10-phenanthroline)

Two novel complexes of Sm(III) and Dy(III) with mixed oxydiacetate (ODA) and 1,10-phenanthroline (phen) ligands were synthesized and their structure and luminescence properties were characterized. The complexes of [Ln(ODA)(phen)·4H₂O]Cl·5H₂O [Ln=Sm and Dy] crystallize in the monoclinic space group P2₁/n with Sm: a=12.3401(14) Å, b=16.821(2), c=12.6847(11) Å, β=107.939(10)°, V=2505.0(5) Å³, Z=4 and ρ=1.841 mg/m³, and with Dy: a=12.289(7) Å, b=16.805(6) Å, c=12.705(4) Å, β=108.144(18)°, V=2493.4(19) Å³, Z=4 and ρ=1.786 mg/m³. The complexes of [Sm(ODA)(phen)·4H₂O]⁺ and [Dy(ODA)(phen)·4H₂O]⁺ excited by UV light produce orange red and lightly white emissions, respectively, via the nonradiative energy transfer from phen to the metals. The quantum yield of the sensitized luminescence of [Dy(ODA)(phen)·4H₂O]⁺ (Q=19%) is much greater than that of [Sm(ODA)(phen)·4H₂O]⁺ (Q=1.4%). The luminescence decay times of the complexes were in a few microsecond range and independent of temperature.     

Development and validation of a sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method for quantitative analysis of bambermycin in livestock and aquatic products: Implications for food safety control and regulatory enforcement

A sensitive and accurate analytical method was developed and validated to detect bambermycin, a commonly used antibiotic in animal feed and livestock. The presence of bambermycin residues in food products can pose health risks to consumers, emphasizing the need for a sensitive and accurate analytical method. A reversed-phase analytical column was utilized with a mobile phase comprising 0.005 mol/L ammonium acetate in 5% acetonitrile (A) and 0.005 mol/L ammonium acetate in 95% acetonitrile (B) to achieve effective chromatographic separation. Quantitative determination of bambermycin in various samples, including beef, pork, chicken, milk, eggs, flatfish, eel, and shrimp, was performed using ultra-high-performance liquid chromatography-tandem mass spectrometry. Sample extraction involved a mixture of methanol and a 25% ammonium hydroxide solution, followed by low-temperature purification and phospholipid removal utilizing a Phree cartridge. The method exhibited a satisfactory recovery rate ranging from 69% to 100%. Validation results demonstrated the reliability, robustness, and accuracy of the method, exhibiting good linearity, precision, and recovery. This validated method can be applied for routine analysis of bambermycin residues, assisting in the development of effective monitoring and control measures to ensure the safety of livestock and aquatic products.     

Gluonic Distribution in the Constituent Quark and Nucleon Induced by the Instantons

Abstract Instanton effects can give large contribution to strong interacting processes, especially at the energy scale where perturbative QCD is no longer valid. However instanton contribution to the gluon contribution in constituent quark and nucleon has never been calculated before. Based on both the constituent quark picture and the instanton model for QCD vacuum, we calculate the unpolarized and polarized gluon distributions in the constituent quark and in the nucleon for the first time. We find that the pion field plays an important role in producing both the unpolarized and the polarized gluon distributions.     

A study of 222Rn concentration of salty underground water and spring water in Jeju,Korea

Journal of Radioanalytical and Nuclear Chemistry - The efficiency transfer procedure from a geometry where a volume source was placed directly on the endcap of a germanium detector to three...     

Scintillators for Alpha and Neutron Radiations Synthesized by Room Temperature Sol–Gel Processing

Solid-state scintillating materials were synthesized by the co-doping of sol–gel components with neutron absorbers [⁶Li and ¹⁰B], organic fluorescence sensitizers such as salicylic acid and 2,5-diphenyloxazole (PPO) and activator 1,4-bis-2-(5-phenyloxazolyl)-benzene (POPOP). The room-temperature sol–gel process through the addition of organic polymers is the key to the successful entrapment of the organic sensitizers and activator in inorganic matrixes. These transparent or translucent sol–gel scintillators were evaluated for alpha radiation and neutron detections.     

Sensitive high-performance anion-exchange chromatographic determination of paeoniflorin and albiflorin by pulsed amperometric detection after solid-phase extraction

We developed a method to simultaneously determine paeoniflorin and albiflorin levels using high-performance anion-exchange liquid chromatography with pulsed amperometric detection (HPAEC-PAD). The main principle of our method includes solid-phase extraction step using Amberlite XAD-2 sorbent to remove sugars and to selectively determine glycosides by PAD. Under these conditions, the linear dynamic range was 0.01–100 μg/mL, and the albiflorin and paeoniflorin detection limits (S/N = 3) were 5 and 10 pg, respectively. The intra- and inter-day precisions (RSDs) were <5.07%, and the average recoveries from Paeoniae Radix and Si-ni-san ranged from 97.12 to 101.15%. Our method showed high selectivity, high sensitivity, and good repeatability for analyzing albiflorin and paeoniflorin in oriental medicinal preparation.     

Effect of water-droplet sizes and radiation-field exposure on the transfer of I<Subscript>2</Subscript> and CH<Subscript>3</Subscript>I gases adsorbed in water

Experimental findings on the transfer of I₂ and CH₃I gases adsorbed in water were accomplished according to different water-droplet sizes with or without exposure to a radiation field, using two different analysis methods: quantitative analyses based on ultraviolet-visible light and gas chromatography-mass spectroscopies. The amount of transferred volatile iodine was strongly influenced by the existence of water, and a little larger amount of I₂ or CH₃I was transferred with bigger sized water droplets than smaller ones when the same amount of water was applied. The decomposition effect was superior to the charging effect under a γ-radiation field in our experimental condition, and the relationship between transferred volatile iodine concentrations and water-droplet sizes in the presence of radioactive sources was following the trend of the absence of radioactive sources.     

Production and Characterization of Cellobiohydrolase from a Novel Strain of <Emphasis Type="Italic">Penicillium purpurogenum</Emphasis> KJS506

A high cellobiohydrolase (CBH)-producing strain was isolated and identified as Penicillium purpurogenum KJS506 according to the morphology and comparison of internal transcribed spacer rDNA gene sequence. When rice straw and corn steep powder were used as carbon and nitrogen sources, respectively, a maximum CBH activity of 2.6 U mg-protein⁻¹, one of the highest among CBH-producing microorganisms, was obtained. The optimum temperature and pH for CBH production were 30 °C and 4.0, respectively. The increased production of CBH in P. purpurogenum culture at 30 °C was confirmed by two-dimensional electrophoresis followed by MS/MS sequencing of the partial peptide. The internal amino acid sequences of P. purpurogenum CBH showed a significant homology with hydrolases from glycoside hydrolase family 7. The extracellular CBH was purified to homogeneity by sequential chromatography of P. purpurogenum culture supernatants on a DEAE-sepharose column, a gel filtration column, and then on a Mono Q column with fast-protein liquid chromatography. The purified CBH was a monomeric protein with a molecular weight of 60 kDa and showed broad substrate specificity with maximum activity towards p-nitrophenyl β-d-cellobiopyranoside. P. purpurogenum CBH showed t _1/2 value of 4 h at 60 °C and V _max value of 11.9 μmol min⁻¹ mg-protein⁻¹ for p-nitrophenyl-d-cellobiopyranoside. Although CBHs have been reported, the high specific activity distinguishes P. purpurogenum CBH.