222 research outputs found
Glaciological Data Collected by the 43rd Japanese Antarctic Research Expedition during 2001-2003
Energy metabolism during the maturation of reticulocyte in vitro
1. For the purpose to clarify the mechanism of the revolutional changes in energy metabolism during the reticulocyte maturation the metabolisms of glucose and of the pentose moieties of acid soluble nucleotides have been observed on rabbit reticulocytes incubated in vitro under
various conditions. 2. The maturation of reticulocyte proceeds by using the energy produced by aerobic glycolysis and is arrested in the glucose deficient medium,
but the pentose moieties of purine nucleotide and nucleoside added exogenously serve as the energy source for reticulocyte maturation even in the absence of glucose.
3. The test on the utility efficiency of glucose and inosine as the energy source for reticulocyte maturation revealed that glucose is used more effectively than the pentose moiety of inosine under aerobic condition, which is advantageous for reticulocyte maturation, and vice versa under anaerobic condition, which is comparable to the metabolism of mature red cell. 4. From these results it has been suggested that the maturation of reticulocyte is the process of degradation of RNA and acid soluble nucleotides supported by the aerobic glycolysis, where the degradation products of RNA and acid soluble purine nucleotides provide the purine derivatives as the material for ATP synthesis (36) and the pentose moieties as energy
source. 5. A possible mechanism for the superior utility of glucose to nucleoside pentose during reticulocyte maturation and vice versa in mature red cell has been discussed.</p
Superconductivity of MI(MII0.5, Si0.5)2 (MI=Sr and Ba, MII=Al and Ga), ternary silicides with the AlB2-type structure
Ternary silicides MI(MII0.5, Si0.5)2 (MI=Sr and Ba, MII=Al and Ga) were
prepared by Ar arc melting. Powder X-ray diffraction indicates that they have
the AlB2-type structure, in which Si and MII atoms are arranged in honeycomb
layers and MI atoms are intercalated between them. Electrical resistivity and
dc magnetization measurements revealed that Sr(Al0.5, Si0.5)2 is
superconductive, with a critical temperature for superconductivity (TC) of 4.2
K, while Ba(Al0.5, Si0.5)2 is not at temperatures ranging above 2.0 K.
Sr(Ga0.5, Si0.5)2 and Ba(Ga0.5, Si0.5)2 are also superconductors, with TCs of
5.1 and 3.3 K, respectively.Comment: 5 pages, 3 tables, 4 figure
Age- and sun exposure-dependent differences in 8-hydroxy-2'-deoxyguanosine and Nε-(carboxymethyl)lysine in human epidermis
Aging and exposure to sunlight are two major factors in the deterioration of skin function. In this study, thirty-six fixed human skin samples from sun-exposed and unexposed areas from young and old individuals were used to evaluate the localization of oxidative stress according to levels and distribution of 8-hydroxy-2'-deoxyguanosine and Nε-(carboxymethyl)lysine in samples using immunohistochemistry. In the epidermis of the young, negligible amounts of 8-hydroxy-2'-deoxyguanosine and Nε-(carboxymethyl)lysine were detected in unexposed areas, whereas nuclear 8-hydroxy-2'-deoxyguanosine and cytoplasmic Nε-(carboxymethyl)lysine were increased in the lower epidermis in sun-exposed areas. In contrast, the aged presented prominent nuclear 8-hydroxy-2'-deoxyguanosine and nuclear Nε-(carboxymethyl)lysine in the epidermis of unexposed areas, concomitant with dermal increase in Nε-(carboxymethyl)lysine. However, the immunostaining of 8-hydroxy-2'-deoxyguanosine and Nε-(carboxymethyl)lysine revealed a decrease in the epidermis of sun-exposed areas in the aged. These results suggest an age-dependent difference in the adaptation and protective mechanisms of the epidermis against sunlight-associated oxidative stress, thus necessitating distinct standards for evaluation in each age group. Further investigation is warranted to elucidate underlying molecular mechanisms
Combined index to evaluate N0 neck
To predict occult nodal metastasis in clinical N0 patients with tongue cancer, we developed combined index (CI) : SUVmax of the largest lymph node in PET/CT by weighting coefficient plus its maximum minor axis (< 10 mm) in contrast-enhanced CT (CECT). In this retrospective study, 57 clinical N0 patients with tongue cancer, who underwent elective supraomohyoid neck dissection at cervical levels of I-III were enrolled. The cutoff value of SUVmax of 2.0 obtained using receiver operating characteristic (ROC) analysis predicted the postoperative positive cervical levels containing metastatic lymph nodes from clinical N0 cervical levels in tongue cancer patients with a sensitivity of 54.5% and a specificity of 78.2%. The cutoff value of CI with weighting coefficient of 1.5 obtained using ROC analysis was 9.8 at the maximum area under the curve of 0.750. The cutoff value of 9.8 predicted the postoperative positive cervical levels containing metastatic lymph nodes from clinical N0 cervical levels in tongue cancer patients with a sensitivity of 68.2% and a specificity of 81.5%. These findings suggest that CI of functional PET/CT and morphological CECT components might improve the diagnostic performance of occult nodal metastasis to select clinical N0 patients with tongue cancer preferable for elective neck dissection
Low-Metallicity Star Formation : Prestellar Collapse and Protostellar Accretion in the Spherical Symmetry
The collapse of dense cores with different metallicities is studied by
hydrodynamical calculations coupled with detailed chemical and radiative
processes. For this purpose, we construct a simple chemical network with
non-equilibrium reactions among 15 chemical species, which reproduces the
abundance of important molecular coolants by more detailed network very well.
The evolution is followed until the formation of a hydrostatic protostar at the
center. In a lower-metallicity gas cloud, the temperature during the collapse
remains high owing to less efficient cooling. Using the temperature evolution
at the center as a function the density, we discuss the possibility of
fragmentation during the dust-cooling phase. The critical metallicity for the
fragmentation is 10^{-5}Z_sun assuming moderate elongation of the cloud cores
at the onset of this phase. From the density and velocity distributions at the
time of protostar formation, we evaluate the mass accretion rate in the
subsequent accretion phase. Using these accretion rates, we also calculate the
evolution of the protostars under the assumption of stationary accretion flow.
Finally, we discuss possible suppression of fragmentation by heating of the
ambient gas by protostellar radiation, which is considered important in the
contemporary star formation. We argue that it is negligible for <10^{-2}Zsun.Comment: ApJ in pres
Insertable inductively coupled volumetric coils for MR microscopy in a human 7T MR system
PURPOSE: To demonstrate the capability of insertable inductively coupled volumetric coils for MR microscopy in a human 7T MR system. METHODS: Insertable inductively coupled volume coils with diameters of 26 and 64 mm (D26 and D64 coils) targeted for monkey and mouse brain specimen sizes were designed and fabricated. These coils were placed inside the imaging volume of a transmit/receive knee coil without wired connections to the main system. Signal-to-noise ratio (SNR) evaluations were conducted with and without the insertable coils, and the g-factor maps of parallel imaging (PI) were also calculated for the D64 coil. Brain specimens were imaged using 3D T 2 ∗ -weighted images with spatial resolution of isotropic 50 and 160 μm using D26 and D64 coils, respectively. RESULTS: Relative average (SD) SNRs compared with knee coil alone were 12.54 (0.30) and 2.37 (0.05) at the center for the D26 and D64 coils, respectively. The mean g-factors of PI with the D64 coil for the factor of 2 were less than 1.1 in the left-right and anterior-posterior directions, and around 1.5 in the superior-inferior direction or when the PI factor of 3 was used. Acceleration in two directions showed lower g-factors but suffered from intrinsic low SNR. Representative T 2 ∗ -weighted images of the specimen showed structural details. CONCLUSION: Inductively coupled small diameter coils insertable to the knee coil demonstrated high SNR and modest PI capability. The concept was successfully used to visualize fine structures of the brain specimen. The insertable coils are easy to handle and enable MR microscopy in a human whole-body 7T MRI system
Associations between non-motor symptoms and patient characteristics in Parkinson’s disease: a multicenter cross-sectional study
ObjectiveParkinson’s disease (PD) is characterized by various non-motor symptoms (NMS), such as constipation, olfactory disturbance, sleep disturbance, mental disorders, and motor symptoms. This study aimed to investigate factors associated with NMS in patients with PD.MethodsSymptoms of PD were evaluated using the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), Parts I–IV. NMS was assessed using the MDS-UPDRS Part I (self-assessment of NMS) and rapid eye movement sleep behavior disorder (RBD) questionnaires. Patients were categorized by age into <70 years and ≥ 70 years (older adults) groups, according to disease duration into early-stage and advanced-stage groups with a cut-off value of 5 years for motor symptoms, and by sex into male and female groups.ResultsA total of 431 patients with PD (202 males and 229 females) with a mean age of 67.7 years, a mean disease duration of 6.4 years, and a mean Part I total score of 9.9 participated in this study. The Part I total score was significantly positively correlated (p < 0.01) with disease duration and Part II, III, and IV scores. For Part I sub-item scores, the older group had significantly higher scores for cognitive impairment, hallucinations, sleep problems, urinary problems, and constipation than the <70 years group, whereas the advanced-stage group had significantly higher scores for hallucinations, sleep problems, daytime sleepiness, pain, urinary problems, and constipation (p < 0.05) than the early-stage group. Anxiety was higher in female patients than in male patients, whereas daytime sleepiness, urinary problems, and RBD were higher in male patients than in female patients (p < 0.05). Factors affecting Part I included disease duration, Part II total scores, Part IV total scores, and RBD.ConclusionAccording to the self-questionnaire assessment, NMS was highly severe in older adult patients, those with longer illness duration, subjective and objective motor function impairments, and RBD. Sex-based differences were also observed
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