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We present recent observation results of Sgr A* at millimeter obtained with VLBI arrays in Korea and Japan.
7 mm monitoring of Sgr A* is part of our AGN large project. The results at 7 epochs during 2013-2014, including high resolution maps, flux density and two-dimensional size measurements are presented. The source shows no significant variation in flux and structure related to the G2 encounter in 2014. According to recent MHD simulations by kawashima et al., flux and magnetic field energy can be expected to increase several years after the encounter; We will keep our monitoring in order to test this prediction.
Astrometric observations of Sgr A* were performed in 2015 at 7 and 3.5 millimeter simultaneously. Source-frequency phase referencing was applied and a combined ”core-shift” of Sgr A* and a nearby calibrator was measured. Future observations and analysis are necessary to determine the core-shift in each source.
Glutathione peroxidase (GPx; EC 220.127.116.11) is an important antioxidant enzyme that catalyses the reduction of organic and inorganic hydroperoxides to water in oxygen-consuming organisms, using glutathione as an electron donor. Here, we report the characterization of a GPx of Cryptosporidium parvum (CpGPx). CpGPx contained a standard UGU codon for cysteine instead of a UGA opal codon for seleno-cysteine (SeCys) at the active site, and no SeCys insertion sequence (SECIS) motif was identified within the 3′-untranslated region (UTR) of CpGPx, which suggested its selenium-independent nature. In silico and biochemical analyses indicated that CpGPx is a cytosolic protein with a monomeric structure. Recombinant CpGPx was active over a wide pH range and was stable under physiological conditions. It showed a substrate preference against organic hydroperoxides, such as cumene hydroperoxide and t-butyl hydroperoxide, but it also showed activity against inorganic hydroperoxide, hydrogen peroxide. Recombinant CpGPx was not inhibited by potassium cyanide or by sodium azide. The enzyme effectively protected DNA and protein from oxidative damage induced by hydrogen peroxide, and was functionally expressed in various developmental stages of C. parvum. These results collectively suggest the essential role of CpGPx for the parasite's antioxidant defence system.
We present the results of radio monitoring observations of Sgr A* at 7 mm (i.e. 43 GHz) with the VLBI Exploration of Radio Astrometry (VERA), which is a VLBI array in Japan. VERA provides angular resolution on millisecond scales, resolving structures within 100 Schwarzschild radii of Sgr A* , similar to the Very Large Baseline Array (VLBA). We performed multi-epoch observations of Sgr A* in 2005 - 2008, and started monitoring it again with VERA from 2013 January to trace the current G2 encounter event. Our preliminary results in 2013 show that Sgr A* on mas scales has been in an ordinary state as of August 2013, although some fraction of the G2 cloud already passed the pericenter of Sgr A* in April 2013. We will continue monitoring Sgr A* with VERA and the newly developed KaVA (KVN and VERA Array).
We searched the time lag between the intra-day variables (IDVs) of Sagittarius A* at 22, 43, and 86 GHz bands using the Korean VLBI Network (KVN). The time lags between the IDV flare peaks at 22 and 43 GHz are reported, and they suggest that the flare emissions come from adiabatically expanding plasma blobs, ejected close to the Galactic center black hole. We searched the time lags between light curves at 90 and 102 GHz using the Nobeyama Millimeter Array, but could not find significant time lags. In order to detect the diversity of the time lags of Sgr A* flares, we performed observations of Sgr A* in the 22, 43, and 86 GHz bands using the KVN in the winter of 2013. Because the receiver system of KVN can observe Sgr A* in these three bands simultaneously, the KVN is very useful to detect the time lags of Sgr A* flares.
Cysteine proteases of pathogenic protozoan parasites play pivotal roles in the life cycle of parasites, but strict regulation of their activities is also essential for maintenance of parasite physiology and interaction with hosts. In this study, we identified and characterized cryptostatin, a novel inhibitor of cysteine protease (ICP) of Cryptosporidium parvum. Cryptostatin showed low sequence identity to other chagasin-family ICPs, but 3 motifs (NPTTG, GXGG, and RPW/F motifs), which are evolutionarily conserved in chagasin-family ICPs, were found in the sequence. The overall structure of cryptostatin consisted of 8 β-strands that progressed in parallel and closely resembled the immunoglobulin fold. Recombinant cryptostatin inhibited various cysteine proteases, including papain, human cathepsin B, human cathepsin L, and cryptopain-1, with Ki's in the picomolar range. Cryptostatin was active over a wide pH range and was highly stable under physiological conditions. The protein was thermostable and retained its inhibitory activity even after incubation at 95°C. Cryptostatin formed tight complexes with cysteine proteases, so the complexes remained intact in the presence of sodium dodecyl sulfate and β-mercaptoethanol, but they were disassembled by boiling. An immunogold electron microscopy analysis demonstrated diffused localization of cryptostatin within oocystes and meronts, but not within trophozoites, which suggests a possible role for cryptostatin in host cell invasion by C. parvum.
Leucine aminopeptidases (LAPs) are a group of metalloexopeptidases that catalyse the sequential removal of amino acids from the N-termini of polypeptides or proteins. They play an important role in regulating the balance between catabolism and anabolism in living cells. LAPs of apicomplexa parasitic protozoa have been intensively investigated due to their crucial roles in parasite biology as well as their potentials as drug targets. In this study, we identified an M17 leucine aminopeptidase of Cryptosporidium parvum (CpLAP) and characterized the biochemical properties of the recombinant protein. Multiple sequence alignment of the deduced amino acid sequence of CpLAP with those of other organisms revealed that typical amino acid residues essential for metal binding and active-site formation in M17 LAPs were well conserved in CpLAP. Recombinant CpLAP shared similar biochemical properties such as optimal pH, stability at neutral pHs, and metal-binding characteristics with other characterized LAPs. The enzyme showed a marked preference for Leu and its activity was effectively inhibited by bestatin. These results collectively suggest that CpLAP is a typical member of the M17 LAP family and may play an important role in free amino acid regulation in the parasite.
Cryptosporidium parvum is an intracellular protozoan parasite that causes cryptosporidiosis in mammals including humans. In the current study, the gene encoding the cysteine protease of C. parvum (cryptopain-1) was identified and the biochemical properties of the recombinant enzyme were characterized. Cryptopain-1 shared common structural properties with cathepsin L-like papain family enzymes, but lacked a typical signal peptide sequence and contained a possible transmembrane domain near the amino terminus and a unique insert in the front of the mature domain. The recombinant cryptopain-1 expressed in Escherichia coli and refolded to the active form showed typical biochemical properties of cathepsin L-like enzymes. The folding determinant of cryptopain-1 was characterized through multiple constructs with or without different lengths of the pro-domain of the enzyme expressed in E. coli and assessment of their refolding abilities. All constructs, except one that did not contain the full-length mature domain, successfully refolded into the active enzymes, suggesting that cryptopain-1 did not require the pro-domain for folding. Western blot analysis showed that cryptopain-1 was expressed in the sporozoites and the enzyme preferentially degraded proteins, including collagen and fibronectin, but not globular proteins. This suggested a probable role for cryptopain-1 in host cell invasion and/or egression by the parasite.
Lithium based complex hydrides, including lithium aluminum hydrides and lithium borohydride (LiAlH4, Li3AlH6 and LiBH4), are among the most promising materials due to their high hydrogen contents. In the present work, we investigated the hydrogen storage properties of a new combined system of Li3AlH6-LiBH4. The samples were made with small amounts of catalyst under low energy milling conditions. Thermogravimetric analysis (TGA) of a Ti-doped Li3AlH6/2LiBH4 indicated that the degree of hydrogen release reached 7.3 wt. % by the time the sample reached 450iÆc under a heating rate of 2iÆC/min. This increased to 8.8 wt. % when the sample was held at 450iÆCfor additional 8 hours minutes under this condition. The dehydrogenation product was a mixture of LiH and AlB2. This product could be rehydrogenated up to 3.8 wt. % under 24.1 MPa hydrogen pressure and 450iÆC.
This study was performed to assess the efficacy and safety profile of combination treatment with S-1 and cisplatin in patients with locally advanced squamous cell carcinoma of the head and neck.
Eligibility criteria comprised: histologically confirmed squamous cell carcinoma of the head and neck; stage three or four disease with no evidence of distant metastasis; evaluable lesions; adequate organ function; age 20–80 years; and a performance status of two or less. Cisplatin was infused over one hour on day one (75 mg/m2) and S-1 was administered orally for 14 consecutive days (days two to 15). The dosages of S-1 were calculated according to the patients' body surface area: 50 mg twice a day (body surface area <1.5 m2) or 60 mg twice a day (body surface area >1.5 m2). Each course was repeated every three weeks. After two courses, tumour response was evaluated by computed tomography and laryngoscopy. If a response was evident (either complete or partial), the patient received one more course of chemotherapy, before undergoing radical treatment such as radiotherapy or surgery.
All 30 patients were assessable for toxicity, and 29 patients for treatment response. The overall response was 89.7 per cent (complete response: nine; partial response: 17). The two-year estimated overall survival rate was 79.2 per cent. Adverse reactions occurred 128 times during 81 courses in the 30 cases. The most common grade three to four adverse event was neutropenia, which occurred in eight patients. Cases of non-haematological grade three or four toxicity included nausea and vomiting in four patients, stomatitis in two and diarrhoea in one.
S-1 plus cisplatin combination chemotherapy is effective against locally advanced squamous cell carcinoma of the head and neck, with only mild toxicity.
Faecal examinations for helminth eggs were performed on 1869 people from two
riverside localities, Vientiane Municipality and Saravane Province, along the
Mekong River, Laos. To obtain adult flukes, 42 people positive for small
trematode eggs (Opisthorchis viverrini, heterophyid, or
lecithodendriid eggs) were treated with a 20–30 mg kg−1 single dose
of praziquantel and purged. Diarrhoeic stools were then collected from 36 people
(18 in each area) and searched for helminth parasites using stereomicroscopes.
Faecal examinations revealed positive rates for small trematode eggs of 53.3%
and 70.8% (average 65.2%) in Vientiane and Saravane Province, respectively.
Infections with O. viverrini and six species of intestinal
flukes were found, namely, Haplorchistaichui, H. pumilio, H.
yokogawai, Centrocestus caninus,Prosthodendrium molenkampi, and Phaneropsolus
bonnei. The total number of flukes collected and the proportion of
fluke species recovered were markedly different in the two localities; in
Vientiane, 1041 O. viverrini (57.8 per person) and 615 others
(34.2 per person), whereas in Saravane, 395 O. viverrini (21.9
per person) and 155207 others (8622.6 per person). Five people from Saravane
harboured no O. viverrini but numerous heterophyid and/or
lecithodendriid flukes. The results indicate that O. viverrini
and several species of heterophyid and lecithodendriid flukes are endemic in
these two riverside localities, and suggest that the intensity of infection and
the relative proportion of fluke species vary by locality along the Mekong River
The principal interests in this work are energetic-beam control of carbon-film properties and the roles of doping and surface morphology in field emission. Carbon films with variable sp3-bonding fraction were deposited on n-type Si substrates by ArF (193 nm) pulsed-laser ablation (PLA) of a pyrolytic graphite target, and by direct metal ion beam deposition (DMIBD) using a primary Cs+ beam to generate the secondary C- deposition beam. The PLA films are undoped while the DMIBD films are doped with Cs. The kinetic energy (KE) of the incident C atoms/ions was controlled and varied over the range from ∼25 eV to ∼175 eV. Earlier studies have shown that C films' sp3-bonding fraction and diamond-like properties can be maximized by using KE values near 90 eV. The films' surface morphology, sp3–bonding fraction, and Cs-content were determined as a function of KE using atomic force microscopy, TEM/EELS, Rutherford backscattering and nuclear reaction measurements, respectively. Field emission (FE) from these very smooth undoped and Cs-containing films is compared with the FE from two types of deliberately nanostructured carbon films, namely hot-filament chemical vapor deposition (HF-CVD) carbon and carbon nanotubes grown by plasma-enhanced CVD. Electron field emission (FE) characteristics were measured using ∼25-μm, ∼5-μm and ∼1-μm diameter probes that were scanned with ∼75 nm resolution in the x-, y-, and z-directions in a vacuum chamber (∼5 × 10-7 torr base pressure) equipped with a video camera for viewing. The hydrogen-free and very smooth a-D or a-C films (with high or low sp3 content, and with or without ∼1% Cs doping) produced by PLD and DMIBD are not good field emitters. Conditioning accompanied by arcing was required to obtain emission, so that their subsequent FE is characteristic of the arc-produced damage site. However, deliberate surface texturing can eliminate the need for conditioning, apparently by geometrical enhancement of the local electric field. But the most promising approach for producing macroscopically flat FE cathodes is to use materials that are highly nanostructured, either by the deposition process (e.g. HF-CVD carbon) or intrinsically (e.g. carbon nanotubes). HF-CVD films were found to combine a number of desirable properties for FE displays and vacuum microelectronics, including the absence of conditioning, low turn-on fields, high emission site density, and apparent stability and durability during limited long-term testing. Preliminary FE measurements revealed that vertically aligned carbon nanotubes are equally promising.
The present study aims at investigating the effect of co-doping on the photoluminescence(PL) property of Zn2SiO4:Mn phosphor. Experimental data were interpreted by the first principles embedded-cluster discrete variational (DV)-Xα method.
In the last few years, many proposals have been made requiring either changes in the administration and financing of the United Nations or a revision of the Charter of the United Nations. While some progress has been made in the first category of problems, to the extent that they require primarily changes in the working of the United Nations Secretariat, it became quite obvious that a revision of the Charter is not likely to be made in the near future. It may be possible, however, to achieve important changes in the functioning of the principal organs of the United Nations—the Security Council, the General Assembly and the International Court of Justice—without revision. Pending a change in the international situation, various steps can be taken in the interim that would considerably improve the functioning of these organs, and achieve some of the desirable goals by measures that, while not ideal, will provide practical solutions for a few important problems. Several such solutions are investigated in the three sections of this essay.
The transport mechanism underlying the colossal magnetoresistance (CMR) of doped manganites is not yet understood and their technological applications are limited by the high fields (∼IT) required to obtain any significant MR. Following the development of a polymeric chemical synthesis route, we have investigated the O2p unoccupied density of states in sol-gel derived Lal-xSrxMnO3 (0 < x < 0.7) thin films grown epitaxially on LaA1O3, by electron energy-loss spectroscopy at sub-eV resolution. The spectra show a distinct prepeak in the OK edge at the Fermi level, the intensity of which correlates directly with the conductivity of the film. Similar correlation was also obtained for La0.7Sr0.3MnO3-z annealed in vacuum to obtain well defined oxygen content (z) in the film. This confirms that the charge carriers in these manganese perovskites have significant oxygen 2p hole character and suggests that the “double exchange” mechanism has to be modified. In another set of experiments we have studied room-temperature field amplification effects to enhance the low-field sensitivity of La0.7Sr0.3MnO3-z films sandwiched between two thin rectangular slices of either α-Fe or Mn-Zn ferrite. This field amplification leads to an enhanced low-field MR value as high as 6% at an external field of 500 Oe which is 6 times the value observed without the amplification.
Polycrystalline Si (Poly-Si) films were successfully grown at temperature less than 500 °C by using a direct Si ion beam deposition technique. In this process, the ion beam energy of Si- is directly coupled to the formation of the films. High substrate temperature (>600 °C), normally required for conventional CVD techniques, has been a major barrier for the Poly-Si Thin Film Transistor Liquid Crystal Display (TFT LCD) which uses a glass substrate. Thus, the ability to produce Poly-Si film below the glass transition temperature and to control the grain size will make this direct Si- ion beam deposition process a potential alternative technique for future TFT LCD. The grain size dependence on the ion beam energy and substrate temperature was investigated using a Transmission Electron Microscope (TEM). The grain size could be controlled from 0.1 μm to 1 μm at ion beam energies from 10 to 50 eV with a substrate temperature less than 500 °C. The resistivity of the as-deposited film was of the order of 100 Ωcm due to in-situ doping effect.
Too much has been written lately about the limited approach to human rights at Dumbarton Oaks, the struggle at the San Francisco Conference, and the great flowering of declarations, conventions, covenants and instruments to implement them in the last fifty years. Instead of adding another retelling of these more than twice-told tales, this essay tries to look at the origin of two less known contributions to the law of human rights—the broad nondiscrimination clause which added a more practical meaning to the vague “human rights and fundamental freedoms” phrase; and the bold addition of economic and social rights to the more traditional civil and political rights.
This paper analyzes the legal implications of the Draft Resolution and Draft Agreement Relating to the Implementation of Part XI of the United Nations Convention on the Law of the Sea of 10 December 1982, as well as the effectiveness of the proposed arrangements under international law.