32 research outputs found

    日本の沖縄での潰瘍性大腸炎患者のサイトメガロウイルスの遺伝子型の分布

    Get PDF
    博士(医学)琉球大

    Molecular chemical concepts for the synthesis of novel ceramics

    No full text
    There is presently much effort in basic science and applied research to work on-novel ceramics with properties far beyond those of the existing materials. Aim and scope of the research in this field is to develop materials with superior thermomechanical, physical and chemical properties. In particular, the synthesis of carbide- and nitride-based ceramic,devices from molecular compounds such as inorganic polymers has attracted increasing attention for the production of dense and porous ceramic composites, fibers or coatings. Another important novel development is the synthesis of hybrid materials using sol-gel techniques. In our studies hybrid organic-inorganic xerogels; of general formula (NCN)(1.5)Si-(CH2)(n)-Si(NCN)(1.5) and (NCN)(1.5)Si-CH2-C6H4-CH2-Si(NCN)(1.5) were prepared. These polymeric carbodiimide-gels represent a novel approach to the field of non-oxidic hybrid materials. All the products were characterized by nitrogen adsorption (BET), SEM, TEM and FTIR spectroscopy. Moreover, novel ceramic compositions such as binary carbon nitrides can be synthesized by the polymer-to-ceramic transformation route. The sp(3)-hybridised carbon nitrides are expected to exhibit ultra high hardness. We prepared ON precursor compounds based on the tri-s-triazine unit. The molecular, oligomeric and polymeric compounds exhibit not only high thermal stability, but also interesting optical properties such as strong photoluminescence. Preliminary experiments indicate that the precursors are promising candidates for high pressure bulk synthesis of ceramic CNx materials

    Synthesis and characterization of alkylene-bridged silsesquicarbodiimide hybrid xerogels

    No full text
    Hybrid polymers consisting of flexible organic chains within an inorganic silsesquicarbodiimide network of the type [(NCN)1.5Si-(CH2)x-Si(NCN)1.5]n (where x=2, 6, and 8) were prepared by mild sol–gel polycondensation reactions of bis(trichlorosilyl)alkanes and bis(trimethylsilyl)carbodiimide. The presence of the NCN groups in xerogel structures was identified by FTIR spectra. The composition and molecular structures were characterized by elemental analysis, solid-state 13C CP MAS- and 29Si CP MAS-NMR spectroscopies, and XRD. Scanning as well as transmission electron microscopies were used to examine the morphology of the xerogels. In addition, the pore structure of the materials was examined by the gas adsorption (BET) method and it is found that the surface area decreased with increasing length of the alkylene spacing group. Hybrid polymers consisting of flexible organic chains within an inorganic silsesquicarbodiimide network of the type [(NCN)1.5Si-(CH2)x-Si(NCN)1.5]n (where x=2, 6, and 8) were prepared by mild sol–gel polycondensation reactions of bis(trichlorosilyl)alkanes and bis(trimethylsilyl)carbodiimide. The presence of the NCN groups in xerogel structures was identified by FTIR spectra

    Polymer-derived SiBCN ceramic and their potential application for high temperature membranes

    No full text
    A novel preceramic polymer suitable to form a SiBCN ceramic was synthesized by hydroboration reaction of 1,3,5-trivinyl-1,3,5-trimethyl-cyclotrisilazane with borane dimethylsulphide. The obtained polymer denoted as poly (borosilazane) was characterised by FT-IR and NMR spectroscopy and its thermal stability was studied by thermal gravimetric analysis in combination with in situ mass spectrometry (TG/MS). The polymer-to-ceramic transformation was achieved at 1050 degrees C in inert argon atmosphere yielding black and X-ray amorphous SiBCN ceramics thermally stable up to 1800 degrees C. Using the dip-coating technique, a SiBCN ceramic thin film was formed on a porous alumina substrate. N-2 sorption isotherm analysis revealed that the thin film contained a small amount of micropores of about 0.6 nm in diameter, as well as mesopores between 2.7 and 6 nm in size. The total pore volume was found to be about three orders of magnitude smaller than that of a hydrogen permselective amorphous silica membrane derived from polysilazane. These results indicated potential application of the SiBCN thin film as a molecular sieve membrane suitable for high-temperature separation of small gas molecules like hydrogen below 0.3 nm in size

    COVID-19 Pneumonia Classification Based on NeuroWavelet Capsule Network

    No full text
    Since it was first reported, coronavirus disease 2019, also known as COVID-19, has spread expeditiously around the globe. COVID-19 must be diagnosed as soon as possible in order to control the disease and provide proper care to patients. The chest X-ray (CXR) has been identified as a useful diagnostic tool, but the disease outbreak has put a lot of pressure on radiologists to read the scans, which could give rise to fatigue-related misdiagnosis. Automatic classification algorithms that are reliable can be extremely beneficial; however, they typically depend upon a large amount of COVID-19 data for training, which are troublesome to obtain in the nick of time. Therefore, we propose a novel method for the classification of COVID-19. Concretely, a novel neurowavelet capsule network is proposed for COVID-19 classification. To be more precise, first, we introduce a multi-resolution analysis of a discrete wavelet transform to filter noisy and inconsistent information from the CXR data in order to improve the feature extraction robustness of the network. Secondly, the discrete wavelet transform of the multi-resolution analysis also performs a sub-sampling operation in order to minimize the loss of spatial details, thereby enhancing the overall classification performance. We examined the proposed model on a public-sourced dataset of pneumonia-related illnesses, including COVID-19 confirmed cases and healthy CXR images. The proposed method achieves an accuracy of 99.6%, sensitivity of 99.2%, specificity of 99.1% and precision of 99.7%. Our approach achieves an up-to-date performance that is useful for COVID-19 screening according to the experimental results. This latest paradigm will contribute significantly in the battle against COVID-19 and other diseases

    COVID-19 Identification from Low-Quality Computed Tomography Using a Modified Enhanced Super-Resolution Generative Adversarial Network Plus and Siamese Capsule Network

    No full text
    Computed Tomography has become a vital screening method for the detection of coronavirus 2019 (COVID-19). With the high mortality rate and overload for domain experts, radiologists, and clinicians, there is a need for the application of a computerized diagnostic technique. To this effect, we have taken into consideration improving the performance of COVID-19 identification by tackling the issue of low quality and resolution of computed tomography images by introducing our method. We have reported about a technique named the modified enhanced super resolution generative adversarial network for a better high resolution of computed tomography images. Furthermore, in contrast to the fashion of increasing network depth and complexity to beef up imaging performance, we incorporated a Siamese capsule network that extracts distinct features for COVID-19 identification.The qualitative and quantitative results establish that the proposed model is effective, accurate, and robust for COVID-19 screening. We demonstrate the proposed model for COVID-19 identification on a publicly available dataset COVID-CT, which contains 349 COVID-19 and 463 non-COVID-19 computed tomography images. The proposed method achieves an accuracy of 97.92%, sensitivity of 98.85%, specificity of 97.21%, AUC of 98.03%, precision of 98.44%, and F1 score of 97.52%. Our approach obtained state-of-the-art performance, according to experimental results, which is helpful for COVID-19 screening. This new conceptual framework is proposed to play an influential task in the issue facing COVID-19 and related ailments, with the availability of few datasets

    Distribution of cytomegalovirus genotypes among ulcerative colitis patients in Okinawa, Japan

    No full text
    Background/AimsTo determine the prevalence of glycoprotein B (gB), glycoprotein N (gN), and glycoprotein H (gH) genotypes of human cytomegalovirus (HCMV) superimposed on ulcerative colitis (UC) patients in Japan.MethodsFour archived stool samples and 7-archived extracted DNA from stool samples of 11 UC patients with positive multiplex polymerase chain reaction (PCR) results for HCMV were used UL55 gene encoding gB, UL73 gene encoding gN, and UL75 gene encoding gH were identified by PCR. Genotypes of gB and glycoprotein N were determined by sequencing.ResultsAmong 11 samples, 8 samples were amplified through PCR. gB, gN, and gH genotypes were successfully detected in 3 of 8 (37.5%), 4 of 8 (50%), and 8 of 8 (100%), respectively. The distribution of gB and gN genotypes analyzed through phylogenetic analysis were as follows: gB1 (2/3, 66.7%), gB3 (1/3, 33.3%), gN3a (2/4, 50%), and gN3b (2/4, 50%). Other gB genotypes (gB2 and gB4) and gN genotypes (gN1, gN2, and gN4) were not detected in this study. Out of successfully amplified 8 samples of gH genotype, gH1 and gH2 were distributed in 12.5% and 75% samples, respectively. Only 1 sample revealed mixed infection of gH genotype. The distribution of gH1 and gH2 differed significantly (1:6, P<0.05) in UC patients. The distribution of single gH genotype also revealed significant difference in UC patients who were treated with immunosuppressive drug (P<0.05).ConclusionsIn this study, gB1, gN3, and gH2 gene were determined as the most frequently observed genotypes in UC patients, which suggest that there might be an association between these genotypes of HCMV and UC
    corecore