Formation and magnetic properties of InFeP:Ag nanorods fabricated with noble metal Ag using an ion milling method.

The formation, including the density and height of the InFeP:Ag nanorods doped with noble metal Ag using an ion milling method, was preponderantly determined from transmission electron microscopy and x-ray diffraction analyses. We investigate, in particular, the enhanced ferromagnetism of the well-aligned InFeP:Ag nanorods. Auger electron spectroscopy and x-ray photoelectron spectroscopy measurements were carried out in order to investigate the incorporation of Ag and to verify the local chemical bonding of the InFeP:Ag nanorods. The variation of FWHM for the double-crystal x-ray rocking curve and triple-axis diffraction peaks demonstrates that noble metal Ag is incorporated into the InFeP:Ag nanorods. The noticeable ferromagnetic signature (M-H curve) of the InFeP:Ag nanorods is observed and T c persists up to almost 350 K (3.9 × 10-4 emu g-1), as determined by temperature-dependence magnetization (M-T curve) measurements. This study suggests that the InFeP:Ag nanorods should be a potential candidate for the application of spintronic devices.

Dislocation-driven growth of porous CdSe nanorods from CdSe·(ethylenediamine)(0.5) nanorods.

Porous CdSe nanorods having a novel flute-like morphology have been prepared facilely via the hydrothermal treatment of CdSe·(en)0.5 (en = ethylenediamine) nanorods as sacrificial templates. During the hydrothermal process, various crystalline imperfections such as stacking faults and twinning planes appear due to lattice mismatches between orthorhombic CdSe·(en)0.5 and hexagonal wurtzite porous CdSe nanorods and subsequently disappear to release mismatched strains. In the self-healing process of defects, due to the imbalance of in-and-out atomic diffusion, point defects of atomic vacancies are heavily generated in CdSe nanorods to produce volume defects of voids eventually. The photoluminescence of CdSe nanorods shifts to the red region and decreases in intensity with the increase of the hydrolysis time as surface states and selenium vacancies increase. The mean lifetime of photoluminescence increases with the increase of the hydrothermal-treatment time as the fractional amplitude of the surface-state-related component increases.

Ultrastructure of late spermatids and spermatozoa during spermiogenesis in longtooth grouper Epinephelus bruneus from Jeju, Korea.

Ultrastructural characteristics of late spermatids and spermatozoa during spermiogenesis in longtooth grouper Epinephelus bruneus from Jeju, Korea were investigated using transmission and scanning electron microscopy. The spermiogenesis type of E. bruneus belongs to type I because of nuclear rotation occurrence. The spherical head of late spermatids and spermatozoa ultrastructurally consist of apple-shaped nucleus, nuclear notch (Y or branch-shaped) and nuclear fossa. The midpiece contains the proximal centriole (9+0 microtubule structure), two centrioles connection structure (three osmophilic filaments), the distal centriole (9+0 microtubule structure), an osmophilic basal foot, two necklaces (six or seven osmophilic particles) and osmophilic alar sheets. It contains six to nine spherical mitochondria showing two rows arrangement type. Also a flagellum (9+2 microtubule structure) presents six swelling shaped segments type lateral fins with regular interval. Consequently, ultrastructural features of E. bruneus spermatids and spermatozoa contribute to provide useful systematic characters for taxonomic purpose. It may contribute to study that whether ultrastructural features of cellular organelles (cytoplasmic canal, necklace and lateral fins) correlate to physiological function or not on the duration of motility and survival in fish spermatozoa.

Characterization of cholecystokinin-producing cells and mucus-secreting goblet cells in the blacktip grouper, Epinephelus fasciatus.

The characteristics and distributions of cholecystokinin (CCK)-producing cells and mucus-secreting goblet cells were investigated in the digestive tract of the blacktip grouper (Epinephelus fasciatus). CCK-producing cells were scattered throughout the digestive tract. The highest frequency of CCK-producing cells was observed in the anterior intestine portion and pyloric ceca, with a very small number of cells distributed as far as the rectum. Mucus-secreting goblet cells were found to differ remarkably in their regional distributions and relative frequencies. High frequencies of mucus-secreting goblet cells were found in the digestive tract, mainly in the anterior intestine portion and pyloric ceca, but not the esophagus; the frequency decreased slightly toward the rectum. Our result suggests that food digested by gastric acid in the stomach moves on the anterior (including the pyloric ceca) and mid intestine portion, thereby ensuring effective stimulation of the CCK-producing cells. In addition, the distribution pattern of the CCK-producing cells closely resembled that of mucus-secreting goblet cells. In E. fasciatus, CCK-producing cells and mucus-secreting goblet cells seem to be well adapted to promoting optimal control of the digestive process.

Electrophoretic separation of gold nanoparticles according to bifunctional molecules-induced charge and size.

Gold nanospheres modified with bifunctional molecules have been separated and characterized by using agarose gel electrophoresis as well as optical spectroscopy and electron microscopy. The electrophoretic mobility of a gold nanosphere capped with 11-mercaptoundecanoic acid (MUA) has been found to depend on the number of MUA molecules per gold nanosphere, indicating that it increases with the surface charge of the nanoparticle. The extinction spectrum of gold nanospheres capped with MUA at an MUA molecules per gold nanosphere value of 1000 and connected via 1,6-hexanedithiol (HDT) decreases by 33% in magnitude and shifts to the red as largely as 22 nm with the increase of the molar ratio of HDT to MUA (R(HM)). Gold nanospheres capped with MUA and connected via HDT have been separated successfully using gel electrophoresis and characterized by measuring reflectance spectra of discrete electrophoretic bands directly in the gel and by monitoring transmission electron microscope images of gold nanoparticles collected from the discrete bands. Electrophoretic mobility has been found to decrease substantially with the increment of HDT to MUA, indicating that the size of aggregated gold nanoparticles increases with the concentration of HDT.

Evaluation of Fertilizing Ability using Frozen Thawed Sperm in the Longtooth Grouper, Epinephelus bruneus.

This study examines the effects on fertilization rate (FR), hatching rate (HR), and normal individual rate after artificial fertilization using frozen thawed sperm according to the cryoprotectant (DMSO) concentration and the period of cryopreserved sperm of longtooth grouper, Epinephelus bruneus. Performing artificial fertilization using frozen-thawed sperm, after freezing the sperm at different DMSO concentration of 5.0%, 7.5%, 10.0% respectively, FR were (DMSO 5.0%: 99.5±0.8%, DMSO 7.5%: 99.5±0.7%, and DMSO 10.0%: 99.6±0.6%). The results are not significantly different from the control fresh sperm (100%). HR also (DMSO 5.0%: 96.2±2.3%, DMSO 7.5%: 95.3±3.6%, 10.0%: 96.6±1.8%) were not significantly different in each group. The normal individual rate after hatching using with control fresh sperm (98.4%±0.5) and DMSO concentration level of 5.0% (97.8±0.1%) were not significantly different. However, with 7.5% (97.2±0.6%) and 10.0% DMSO concentrations (95.9±0.2%) are lower than the normal individual rate after hatching observed in the control and 5.0% DMSO. Performing artificial fertilization using frozen-thawed sperm at different frozen period (2 days, 2 years, and 3 years), 10% DMSO FR and HR of 3 years (FR; 66.8±1.8%, HR: 82.0±12.9%) and 2 years (FR; 78.5±14.8%, HR: 79.3±0.6%) cryopreserved sperm were lower than control (FR; 100%, HR: 91.1±3.6%) and 2 days cryopreserved sperm (FR; 99.6±0.6%, HR: 96.6±1.8%). These results suggest suitable DMSO concentration ranges of cryopreservation sperm for E. bruneus is 5 to 10% and with 2 to 3 years cryopreservation period, cryopreservation sperm can be useful for seed production.

Effect of Water Temperature and Salinity on the Fertilized Egg Development and Larval Development of Sevenband Grouper, Epinephelus septemfasciatus.

The fertilized eggs of E. septemfasciatus are spherical and transparent with buoyancy at 790 to 890 µm (average 821.8±2.0 µm) in diameter with 170 to 230 µm oil globules (average 192.9±0.93 µm). Hatching began approximately 46 and 35 hours after fertilization at 22.0°C and 25.0°C water temperature, respectively. The average total length of newly hatched larvae was 1.75±0.03 mm. Most of the yolk and oil globules were absorbed within 3 to 4 days after hatching. The larvae reached 2.48 to 2.72 mm in total length, and their mouths and anuses opened at 3 to 4 days after hatching. In this time, the mouth diameters of the larvae were 0.209 to 0.238 mm. The larvae reached 3.24 to 4.15 mm in total length at 11 to 17 days after hatching, and began to metamorphose at the time the second dorsal and pelvic spines appeared and elongated. The abdominal cavity was densely lined with melanophores. The larvae reached 5.12 mm in total length at 24 days after hatching.

Direct observation of conformation-dependent pathways in the excited-state proton transfer of 7-hydroxyquinoline in bulk alcohols.

The excited-state proton transfer (ESPT) of 7-hydroxyquinoline (7HQ) in bulk alcoholic solvents has been explored with variation of protic hydrogen atoms as well as alcohols. By measuring time-resolved kinetic profiles at two different excitation wavelengths, we have observed conformation-specific pathways in the ESPT of 7HQ. There are two possible rotamers of 7HQ according to the configuration of its hydroxyl group, which are trans and cis. On one hand, trans-7HQ cannot undergo proton transfer within its excited-state lifetime because the internal rotation of the hydroxyl group to form cis-7HQ hardly occurs. On the other hand, some cis-7HQ molecules exist as cyclic complexes of 7HQ·(alcohol)(2) at the moment of excitation, and the cyclic complexes can undergo ESPT rapidly via tunneling. However, the other cis-7HQ molecules should undergo solvent reorganization to form cyclic 7HQ·(alcohol)(2) complexes prior to intrinsic ESPT, and the solvent reorganization becomes the rate-determining step. In contrast to proton transfer, where intrinsic ESPT and solvent reorganization have been observed separately in time-resolved kinetic profiles, intrinsic deuteron transfer is too slow to be distinguished kinetically from solvent reorganization.

Identification of small molecules inducing apoptosis by cell-based assay using fission yeast deletion mutants.

The cell-based assay using yeast deletion mutants has been recognized as an efficient analysis to discover therapeutic compounds and reveal their mode of action. In this study, S. pombe deletion mutants-based HTS screening was carried out to identify potential anti-cancer agents. The NCI chemical library of 5700 compounds was screened using kit strains, which consisted of S. pombe mutants harboring deletions in genes involved in DNA repair and mitotic control. During the screening, we identified 40 compounds conferring growth inhibition of S. pombe. Their anti-tumorigenic properties were examined by phenotypic effect on S. pombe, flow cytometry and apoptosis analysis of human cancer. Here, we report hit compounds inducing apoptosis for development of anti-cancer agents suggesting that S. pombe deletion mutants are useful in identifying potential anti-cancer agents in human cancer therapeutics.