Coherent optical control of the quantum state of a single quantum Dot

Picosecond optical excitation was used to coherently control the excitation in a single quantum dot on a time scale that is short compared with the time scale for loss of quantum coherence. The excitonic wave function was manipulated by controlling the optical phase of the two-pulse sequence through timing and polarization. Wave function engineering techniques, developed in atomic and molecular systems, were used to monitor and control a nonstationary quantum mechanical state composed of a superposition of eigenstates. The results extend the concept of coherent control in semiconductors to the limit of a single quantum system in a zero-dimensional quantum dot.     

Localization of metastable atom beams with optical standing waves: nanolithography at the heisenberg limit

The spatially dependent de-excitation of a beam of metastable argon atoms, traveling through an optical standing wave, produced a periodic array of localized metastable atoms with position and momentum spreads approaching the limit stated by the Heisenberg uncertainty principle. Silicon and silicon dioxide substrates placed in the path of the atom beam were patterned by the metastable atoms. The de-excitation of metastable atoms upon collision with the surface promoted the deposition of a carbonaceous film from a vapor-phase hydrocarbon precursor. The resulting patterns were imaged both directly and after chemical etching. Thus, quantum-mechanical steady-state atom distributions can be used for sub-0.1-micrometer lithography.     

Broth from canned clams is suitable for use as an excellent source of free vitamin B12

Vitamin B(12) was assayed and characterized in the broth of canned clams (boiled plain). The broth contained considerable amounts of vitamin B(12) (2.7-14.1 μg/100 g, 1.3-6.7 μg/can). HPLC and LC/ESI-MS/MS chromatograms demonstrated that the clam broth contained true vitamin B(12). Gel filtration experiments indicated that most (72%) of the vitamin B(12) found in the broth was recovered in free vitamin B(12) fractions. These results indicate that the clam broth would be suitable for use an excellent source of free vitamin B(12) for elderly persons with food-bound vitamin B(12) malabsorption.     

Infiltrating Foxp3+ Regulatory T cells and Histopathological Features in Canine Classical and Spermatocytic Seminomas

In humans, regulatory T (T reg) cells are known to play a critical role in both the regulation of immune homoeostasis and the progression of cancer. However, there is little information about the identification, characterization and the function of T reg cells in canine tumours. We identified T reg cells in 28 canine seminoma samples using a Forkhead box P3 (Foxp3) antibody and investigated the relationship between T reg cell infiltration and histopathological features of classical and spermatocytic seminomas (SE and SS, respectively). The Foxp3 protein showed nuclear immunostaining in infiltrating lymphocytes, and Foxp3+ cells were diffused or focally distributed in seminoma tissues. Foxp3+ cells were frequently present in the SS histotype, in seminomas that showed no evidence of tumour cell invasion into the vessels and in seminomas showing a diffuse growth pattern with three cell types. Neither the SE/SS histotype nor the histopathological features of the tumour correlated with Foxp3+ cell counts. These results indicate that Foxp3+ T reg cells may be associated with a less malignant histological phenotype or may not play a critical role in the immune response of canine seminomas. Moreover, Foxp3+ T reg cells may be associated with SS seminoma, but further studies, involving a larger number of samples, are required to better understand whether these cells play a critical role in the immune response in canine seminomas. This is the first report to demonstrate the characteristics of T reg cell infiltration in canine seminoma.     

Identification of the DDAH2 Protein in Pig Reproductive Tract Mucus: A Putative Oestrus Detection Marker

Precisely detecting oestrus is important for artificial insemination. The aims of this study were to identify oestrus‐specific sow mucus proteins to determine the optimal time for artificial insemination. The proestrous‐ and oestrous‐stage mucus proteins were purified and analysed with proteomic tools such as two‐dimensional gel electrophoresis and matrix‐assisted laser desorption/ionization–time‐of‐flight analyses. Among the differentially expressed proteins, the dimethylarginine dimethylaminohydrolase 2 (DDAH2) protein showed a 3.6‐fold increase during the proestrous stage compared to that during the oestrous stage. A western immunoblot study revealed that two of three sow mucus samples clearly showed negative anti‐DDAH2 antibody activity during the oestrous stage. This study demonstrated that the pig DDAH2 mucus protein exists during the proestrous stage, but not during the oestrous stage, suggesting that mucus DDAH2 could be useful as an oestrus detection marker.     

Identification of vitamin B12 and pseudovitamin B12 from various edible shellfish using liquid chromatography–electrospray ionization/tandem mass spectrometry

In this study, the vitamin B₁₂ contents were analyzed in the edible portions of various shellfish (bivalves and snails). High vitamin B₁₂ contents (30.5–53.3 μg/100 g wet weight) were detected in mussels, surf clams, bloody clams, and freshwater clams. However, scallops and abalone had extremely low vitamin B₁₂ contents (0.1–1.1 μg/100 g wet weight) which was attributed to only the muscle portions being edible. These results suggest that high levels of vitamin B₁₂ are accumulated in the viscera of shellfish. Vitamin B₁₂ levels were also significantly higher in bivalves than in snails. The corrinoid compounds purified from all bivalves were identified as “true” vitamin B₁₂ using liquid chromatography–electrospray ionization/tandem mass spectrometry. In edible snails, abalone, and pond snails, however, both vitamin B₁₂ and pseudovitamin B₁₂ (an inactive corrinoid) were observed to be the major and minor corrinoid compounds, respectively. Based on these results, we conclude that the whole bodies of these edible bivalves are excellent sources of vitamin B₁₂ for humans.     

Two functional channels from primary visual cortex to dorsal visual cortical areas

Relationships between the M and P retino-geniculo-cortical visual pathways and "dorsal" visual areas were investigated by measuring the sources of local excitatory input to individual neurons in layer 4B of primary visual cortex. We found that contributions of the M and P pathways to layer 4B neurons are dependent on cell type. Spiny stellate neurons receive strong M input through layer 4Calpha and no significant P input through layer 4Cbeta. In contrast, pyramidal neurons in layer 4B receive strong input from both layers 4Calpha and 4Cbeta. These observations, along with evidence that direct input from layer 4B to area MT arises predominantly from spiny stellates, suggest that these different cell types constitute two functionally specialized subsystems.     

Femtosecond Dynamics of Excited-State Evolution in

Time-resolved absorption spectroscopy on the femtosecond time scale has been used to monitor the earliest events associated with excited-state relaxation in tris-(2,2'-bipyridine)ruthenium(II). The data reveal dynamics associated with the temporal evolution of the Franck-Condon state to the lowest energy excited state of this molecule. The process is essentially complete in approximately 300 femtoseconds after the initial excitation. This result is discussed with regard to reformulating long-held notions about excited-state relaxation, as well as its implication for the importance of non-equilibrium excited-state processes in understanding and designing molecular-based electron transfer, artificial photosynthetic, and photovoltaic assemblies in which compounds of this class are currently playing a key role.     

Morpho-Physiological Response of Oryza glaberrima to Gradual Soil Drying

Soil drought occurrence during dry season has been the main constraint, besides prolonged flooding during rainy season, in increasing cropping intensity and rice productivity in tropical riparian wetland. Use of drought tolerant rice genotype might be a suitable option for overcoming such problem. This study focused on the effects of gradual soil drying during early vegetative growth stage on morphological and physiological traits of five Oryza glaberrima genotypes, namely RAM12, RAM14, RAM59, RAM97 and RAM101, and two Oryza sativa subsp japonica genotypes, i.e. Koshihikari and Minamihatamochi. The plants were subjected to 6 d of gradual soil drying condition from 15 days after transplanting (DAT) to 20 DAT, and were allowed to recover until 22 DAT. Gradual soil drying reduced plant growth as indicated by dry mass accumulation. Drought reduced stomatal conductance and increased leaf rolling score of all the genotypes. All the genotypes showed comparable response on stomatal conductance, but O. glaberrima genotypes performed higher in leaf rolling recovery. Meanwhile, O. sativa genotypes decreased total leaf area and specific leaf area, but increased specific leaf weight in order to avoid further damages due to drought stress. Drought tolerance mechanisms in RAM101, RAM12, RAM59 and RAM14 were associated with leaf morpho-physiological responses, root traits and dry biomass accumulation.