Dispersion of Graphene in an Aqueous Solution with Poly(sodium 4-styrenesulfonate) Monitored by Capillary Electrophoresis

Graphene was dispersed in an aqueous solution with poly(sodium 4-styrenesulfonate) as a dispersant. The charge of the graphene came to be apparently negative by the adsorption of poly(4-styrenesulfonate) ion (PSS). Two kinds of PSS were examined: the average molecular masses of 70,000 and 1,000,000 (PSS 70,000 and PSS 1,000,000, respectively). Capillary electrophoresis was used to evaluate the dispersion of the apparently anionic graphene in an aqueous solution. A broad signal corresponding to the dispersed graphene was detected in the electropherograms. The effective electrophoretic mobility of the dispersed graphene was somewhat larger at higher concentrations of PSS 70,000, suggesting that the adsorbed amount of PSS 70,000 increased. Even when the separation buffer did not contain PSS, the broad signal of the anionic graphene was still detected. The peak height and/or the peak area, as well as the effective electrophoretic mobility of the graphene decreased little at the reduced applied voltages, i.e., at longer separation/detection time. Therefore, the adsorption of PSS is irreversible or the desorption of PSS from the graphene surface is very slow. Accordingly, the dispersed graphene with PSS would be separated from the matrix PSS by the electrophoretic separation

Potential for Porphyry Copper Deposits in Northern Tōhoku (or the Exploration Potential for Base and Precious Metal Deposits in Japan 2020)

There are no known porphyry copper deposits in Japan. Attempts were made in the past to explain this paradox as the Japanese islands sit above a subduction zone of the type widely accepted to give rise to porphyry-type deposits within subvolcanic magmatic-hydrothermal systems. Is it possible that porphyry copper systems are incompatible with the volcanoplutonic setting of the Japanese islands? In other words, is the established model for the genesis of porphyry copper systems not completely correct, or is it that the elusive Japanese porphyry deposit has not yet been found? We argue that, until proven otherwise, the answer lies in the latter option. In this article, we focus on Akita Prefecture and the surrounding areas and consider the potential for the existence of porphyry copper deposits mainly from an empirical and practical point of view, in contrast with the obviously important petrogenetic and/or tectonic perspectives. We argue that this region is representative of the Thoku province of northern Honshu and that it serves as a proxy for Japan in general. Akita is rich in mineralization styles and deposits, including two main magmatic-hydrothermal deposit types of Neogene age: (i) middle Miocene submarine stratiform volcanogenic massive sulfide (VMS) deposits (Kuroko) and (ii) late Miocene to Pleistocene Ag-Au-bearing polymetallic epithermal/subepithermal veins. In particular the Au-Ag-bearing polymetallic veins, which are comparable to intermediate-sulfidation epithermal deposits commonly associated with porphyry copper systems, were discovered and mined for several centuries before the first Kuroko deposits were found in the late 1800s. Osarizawa, the last active vein mine, closed in 1978. Kuroko deposits, the main source of metal production in Akita in the 20th century, had peak of production in the 1970s, followed by a rapid decline during the 1980s and complete cessation of all mining by 1995. Not surprisingly, the end of mining in Akita, combined with a series of strategic decisions made by the Government and the Japanese metal mining industry, coincided with a cessation of mineral exploration, both in Akita and throughout Japan, with the exception of VMS deposits offshore and limited exploration for bonanza-grade, low-sulfidation epithermal gold deposits in Hokkaido. Our analysis of post-1945 regional exploration in northern Thoku indicates that Kuroko deposits were by far the dominant target and that the number of drill holes in the 1990s accounted for less than 4% of the total completed from the early 1960s to 1995. These data indicate that essentially no mineral exploration has been conducted in Thoku for Au-Ag-bearing polymetallic vein deposits during the past 30+ years. We conclude that exploration stopped too early and certainly before it could have benefited from the significant applicable metallogenic and technological breakthroughs of the last few decades

Enterovirus isolation from children with acute respiratory infections and presumptive identification by a modified microplate method

AbstractObjective: To evaluate a modified microplate method, utilizing HEF, HEp-2, Vero, MDCK and newly introduced RD-18S and GMK cell lines, for virus isolation.Methods: From June to October 2001, 723 throat swab specimens taken from children with acute respiratory infections (ARIs) were inoculated onto these cells. To analyze cell sensitivity, we also inoculated 20 serotypes of stocked enteroviruses.Results: During the period, we isolated 40 Coxsackie A2 (CoxA2), 13 CoxA4, 16 CoxA16, 1 CoxB2, 11 CoxB3, 2 CoxB5, 54 echo16, 2 entero7l and 1 polio2. By observing a cell sensitivity pattern with HEF, HEp-2, Vero, RD-18S, and GMK, we could finally differentiate five enterovirus groups: CoxA except for CoxA16, CoxA16/entero7l, CoxB, echovirus, and poliovirus.Conclusions: With this system, the RD-18S cell line enabled us to isolate CoxA virus, except for CoxA16, for the first time. Differentiation of five enterovirus groups by cell sensitivity simplified the specific identification by neutralization test as a presumptive identification. A modified microplate method may be an appropriate cell combination for virus isolation, especially for enteroviruses, and is expected to be used routinely for virologic diagnosis and to clarify the epidemiology of ARI in children

Measurement of Coolant in a Flat Heat Pipe Using Neutron Radiography

Proceedings of the 10th World Conference on Neutron Radiography (WCNR-10) Grindelwald, Switzerland October 5–10, 2014A newly developed flat heat pipe FGHPTM (Morex Kiire Co.) was experimentally investigated by using neutron radiography. The test sample of the FGHP heat spreader was 65 × 65 × 2 mm3 composed of several etched copper plates and pure water was used as the coolant. Neutron radiography was performed at the E-2 port of the Kyoto University Research Reactor (KUR). The coolant distributions in the wick area of the FGHP and its heat transfer characteristics were measured at heating conditions. Experimental results show that the coolant distributions depend slightly on its installation posture and that the liquid thickness in the wick region remains constant with increasing heat input to the FGHP. In addition, it is found that the wick surface does not dry out even in the vertical posture at present experimental conditions

Modality-Specific Impairment of Hippocampal CA1 Neurons of Alzheimer’s Disease Model Mice

Impairment of episodic memory, a class of memory for spatiotemporal context of an event, is an early symptom of Alzheimer's disease. Both spatial and temporal information are encoded and represented in the hippocampal neurons, but how these representations are impaired under amyloid β (Aβ) pathology remains elusive. We performed chronic imaging of the hippocampus in awake male amyloid precursor protein (App) knock-in mice behaving in a virtual reality environment to simultaneously monitor spatiotemporal representations and the progression of Aβ depositions. We found that temporal representation is preserved, while spatial representation is significantly impaired in the App knock-in mice. This is due to the overall reduction of active place cells but not time cells, and compensatory hyperactivation of remaining place cells near Aβ aggregates. These results indicate the differential impact of Aβ aggregates on two major modalities of episodic memory, suggesting different mechanisms for forming and maintaining these two representations in hippocampus.SIGNIFICANCE STATEMENT:Spatiotemporal memory impairments are common at the early stage of Alzheimer's disease patients. We demonstrate the different impairment patterns of place and time cells in the dorsal hippocampus of head-fixed App knock-in mouse by in vivo two-photon calcium imaging over months under the virtual reality spatiotemporal tasks. These results highlight that place cells were preferentially and gradually damaged nearby Aβ aggregates, while time cells were less vulnerable. We further show these impairments were due to neuronal hyperactivity that occurs near the Aβ deposition. We suggest the differential and gradual impairment in two major modalities of episodic memory under Aβ pathology

A comprehensive survey on quantum computer usage: How many qubits are employed for what purposes?

Quantum computers (QCs), which work based on the law of quantum mechanics, are expected to be faster than classical computers in several computational tasks such as prime factoring and simulation of quantum many-body systems. In the last decade, research and development of QCs have rapidly advanced. Now hundreds of physical qubits are at our disposal, and one can find several remarkable experiments actually outperforming the classical computer in a specific computational task. On the other hand, it is unclear what the typical usages of the QCs are. Here we conduct an extensive survey on the papers that are posted in the quant-ph section in arXiv and claim to have used QCs in their abstracts. To understand the current situation of the research and development of the QCs, we evaluated the descriptive statistics about the papers, including the number of qubits employed, QPU vendors, application domains and so on. Our survey shows that the annual number of publications is increasing, and the typical number of qubits employed is about six to ten, growing along with the increase in the quantum volume (QV). Most of the preprints are devoted to applications such as quantum machine learning, condensed matter physics, and quantum chemistry, while quantum error correction and quantum noise mitigation use more qubits than the other topics. These imply that the increase in QV is fundamentally relevant, and more experiments for quantum error correction, and noise mitigation using shallow circuits with more qubits will take place.Comment: 14 pages, 5 figures, figures regenerate