Energy Transport and Conversion in Semiconductor Nanocrystal Solids

Solids constructed with single and multicomponent nanocrystal represent an exciting new form of condensed matter, as they can potentially capture not only the quantum features of the individual building blocks but also novel collective properties that arise from coupling of nanocrystal components. In this thesis, measurement and interpretation of temperature-dependent thermopower in semiconductor nanocrystal solids are used to elucidate the Fermi energy level and the density of state distribution. The physical understating of temperature dependence of thermopower is, in turn, utilized to develop a powerful tool with which to monitor doping in PbTe nanocrystal solids with different concentrations of Ag2Te nanocrystal dopants. Combining the temperature-dependent thermopower and electrical conductivity measurements provides a unique electronic spectroscopy tool with which to reveal the carrier distribution and dynamics in semiconductor nanocrystal solids

Size-Dependent Phase Transition Memory Switching Behavior and Low Writing Currents in GeTe Nanowires

Synthesis and device characteristics of highly scalable GeTe nanowire-based phase transition memory are reported. The authors have demonstrated reversible phase transition memory switching behavior in GeTe nanowires, and obtained critical device parameters, such as write and erase currents, threshold voltage, and programming curves. The diameter dependence of memory switching behavior in GeTe nanowires was studied and a systematic reduction of writing currents with decreasing diameter was observed, with currents as low as 0.42 mA for a 28 nm nanowire. Results show that nanowires are very promising for scalable memory applications and for studying size-dependent phase transition mechanisms at the nanoscale

Fabrication of Photofunctional Nanoporous Membrane and Its Photoinactivation Effect of Vesicular Stomatitis Virus

Fabrication and photophysical study of photofunctional nanoporous alumina membrane (PNAM) were performed, and its application of photodynamic antimicrobial chemotherapy (PACT) was investigated. Nanoporous alumina membrane (NAM) was fabricated by two-step aluminium anodic oxidation process. Surface of the fabricated NAM was modified with organo-silane agent to induce covalent bonding between NAM and a photosensitizer (PtCP: [5,10,15-triphenyl-20-(4-methoxycarbonylphenyl)-porphyrin] platinum). PtCP was covalently bonded to the surface of the modified NAM by nucleophilic acyl substitution reaction process. The morphology and the photophysical properties of the fabricated PNAM were confirmed with field emission scanning electron microscope (FE-SEM), steady-state spectroscopies, and nanosecond laser-induced time-resolved spectroscopy. For the efficacy study of PNAM in PACT, an enveloped animal virus, vesicular stomatitis virus (VSV), was utilized as a target organism. Antiviral effect of the PNAM-PACT was measured by the extent of suppression of plaque-forming units (PFU) after the light irradiation. In the cultures inoculated with PACT-treated VSV, the suppression of PFU was prominent, which demonstrates that PNAM is a potential bio clean-up tool

Persistent Pemphigus Vulgaris Showing Features of Tufted Hair Folliculitis

Pemphigus vulgaris is an autoimmune blistering disease that commonly involves the scalp. Lesions of pemphigus vulgaris that persist on the scalp for a long period may be accompanied by tufted hair folliculitis. Only two previous accounts of tufted hair folliculitis developing in a lesion of pemphigus vulgaris have been reported. We report a 51-year-old-man with erosions and clusters of hair on the scalp. The scalp lesion had persisted for about 20 years. A histopathological examination of the skin lesion on the scalp revealed separation of the epidermis and clusters of several adjacent hair follicles. The patient was diagnosed with persistent pemphigus vulgaris of the scalp showing features of tufted hair folliculitis

Protein-Directed Self-Assembly of a Fullerene Crystal

Learning to engineer self-assembly would enable the precise organization of molecules by design to create matter with tailored properties. Here we demonstrate that proteins can direct the self-assembly of buckminsterfullerene (C 60) into ordered superstructures. A previously engineered tetrameric helical bundle binds C 60 in solution, rendering it water soluble. Two tetramers associate with one C 60, promoting further organization revealed in a 1.67-Å crystal structure. Fullerene groups occupy periodic lattice sites, sandwiched between two Tyr residues from adjacent tetramers. Strikingly, the assembly exhibits high charge conductance, whereas both the protein-alone crystal and amorphous C 60 are electrically insulating. The affinity of C 60 for its crystal-binding site is estimated to be in the nanomolar range, with lattices of known protein crystals geometrically compatible with incorporating the motif. Taken together, these findings suggest a new means of organizing fullerene molecules into a rich variety of lattices to generate new properties by design

Vardenafil Enhances Oxytocin Expression in the Paraventricular Nucleus without Sexual Stimulation

PurposeOxytocin is associated with the ability to form normal social attachments. c-Fos is an immediate early gene whose expression is used as a marker for stimulus-induced changes in neurons. The effect of phosphodiesterase-5 (PDE-5) inhibitors on oxytocin activation in the brain without sexual stimuli has not yet been reported. In the present study, we investigated the effects of vardenafil on oxytocin and c-Fos expression in the paraventricular nucleus (PVN) of conscious rats.MethodsMale Sprague-Dawley rats weighing 300±10 g were divided into 6 groups (n=5 in each group): the control group, the 1-day-0.5 mg/kg, the 1-day-1 mg/kg, the 1-day-2 mg/kg, the 3-day-1 mg/kg, and the 7-day-1 mg/kg vardenafil administration group. The experiment was conducted without sexual stimulation. Vardenafil was orally administered. The animals in the control group received an equivalent amount of distilled water orally. The expression of oxytocin and c-Fos in the PVN was detected by immunohistochemistry.ResultsOxytocin expression in the PVN was increased by 1 day administration of 2 mg/kg vardenafil, and this effect of vardenafil appeared in a duration-dependent manner. c-Fos in the oxytocin neurons of the PVN was increased by 1 day administration of 2 mg/kg vardenafil, and this effect of vardenafil also appeared in a duration-dependent manner. These results showed that vardenafil augments the expression of oxytocin with activation of oxytocin neurons in the PVN.ConclusionsIn this study, we showed that the PDE-5 inhibitor, vardenafil directly enhances oxytocin expression and also activates oxytocin neurons in the PVN, which indicates that vardenafil may exert positive effects on affiliation behavior and social interaction

Inter-arm arterial pressure difference caused by prone position in the thoracic outlet syndrome patient -A case report-

Thoracic outlet syndrome has neurologic symptoms caused by compression of brachial plexus, blood vessel symptoms are caused by compression of the artery or vein. The authors report a case of sudden decrease in blood pressure of the left arm after turning the patient from supine position to prone position. They confirmed that the patient had thoracic outlet syndrome after performing computed tomography