2,734 research outputs found
Preparation and characterization of carbamoylethyl hemicelluloses
No full textThe reaction of hemicelluloses, isolated from wheat straw, with acrylamide in alkaline aqueous solution was investigated. The degree of substitution (DS, up to 0.65) of the products could be obtained by adjusting the molar ratios of reagent to xylose unit in hemicelluloses (1.0-10.0) and the molar ratios of catalyst to xylose unit in hemicelluloses (0.5-1.6). Changes in the structure of hemicelluloses were verified by FT-IR and 1H and 13C NMR spectroscopies. The results showed that carbamoylethyl groups surely were grafted onto the main chain of hemicelluloses. Moreover, it was also found that the saponification of carbamoylethyl groups to carboxyl groups occurred in alkaline medium. The behavior of modified hemicelluloses was monitored by means of thermo gravimetry (TG) and differential thermal analysis (TGA). It was found that the products had a lower thermal stability than the native hemicelluloses
TP-FRET-Based Fluorescent Sensor for Ratiometric Detection of Formaldehyde in Real Food Samples, Living Cells, Tissues, and Zebrafish
No full textFormaldehyde
(FA, HCHO) is a highly reactive carbonyl species,
which is very harmful to humans and the environment as a tissue fixative
and preservative. Therefore, developing some highly sensitive, selective,
and rapid detection methods is significant for human health in food
safety and environmental protection. Herein, a two-photon (TP) ratiometric
sensor, CmNp-CHO, has been constructed by conjugating
a TP donor (Π-push–pull-structure) with a FA off–on
acceptor (functioned with hydrazide moiety) via a nonconjugated linker
through the fluorescence resonance energy transfer mechanism. Such
a scaffold affords CmNp-CHO a reliable and specific probe
for detecting FA with two well-resolved emission peaks separated by
124 nm. Also, it responds to FA rapidly with high selectivity and
sensitivity during 1.0 min and a large ratio enhancement at I550/I426 with addition
of 0–20μM FA, exhibiting ∼4-fold ratio increase
and a fairly low LOD of 8.3 ± 0.3 nM. Moreover, CmNp-CHO has been successfully employed for detecting FA in live cells, onion
tissues, and zebrafish, exhibiting that CmNp-CHO can
serve as a useful tool for investigating FA in real food application
and offering strong theoretical support and technical means for investigation
of physiological and pathological functions of FA
Relationship between biodistribution of a novel thymidine phosphorylase (TP) imaging probe and TP expression levels in normal mice
No full textObjective: Thymidine phosphorylase (TP) is a key enzyme in the pyrimidine nucleoside salvage pathway and its expression is upregulated in a wide variety of solid tumors. In mice, we previously observed high and specific accumulation levels of our TP imaging probe, radioiodinated 5-iodo-6-[(2-iminoimidazolidinyl)methyl]uracil (IIMU) not only in high-TP-expressing tumors, but also in the liver and small intestine. To clarify the reason for the high accumulation levels of radioiodinated IIMU in the liver and small intestine, we investigated the expression levels of TP in mice in comparison with the biodistribution of radioiodinated IIMU (123I-IIMU). Methods: BALB/cCrSlc mice were injected with 123I-IIMU, and the radioactivity levels [%ID/g (normalized to a mouse of 25 g body weight)] in the tissues of interest were determined 0.5, 1, 3 and 24 h after the injection (n = 5, each time point). To determine the expression levels of TP, BALB/cCrSlc and ddy mice (n = 3/each strain) were euthanized, and the heart, liver, lung, spleen, kidney, stomach, small intestine, large intestine and brain were collected. The mRNA and protein expression levels of TP in these organs were examined by quantitative reverse transcription-polymerase chain reaction and western blot analyses, respectively. Results: In BALB/cCrSlc mice administered 123I-IIMU, markedly high radioactivity levels were observed in the liver [1.568 ± 0.237 (%ID/g)] and small intestine [0.506 ± 0.082 (%ID/g)], whereas those in the other tissues were fairly low [<0.010 ± 0.003 (%ID/g)] 30 min after the injection. The highest expression levels of TP mRNA were also observed in the liver and small intestine among the tissues tested. Immunoblotting showed intense immunoreactive bands of the TP protein for the liver and small intestine, whereas no notable bands were detected for other tissues. Similar expression profiles of TP mRNA and protein were observed in ddy mice. Conclusion: We confirmed TP expression in various tissues of mice at the mRNA and protein levels: high TP expression levels were observed in the liver and small intestine. These high TP expression levels are consistent with the high accumulation levels of 123I-IIMU in these tissues. Our results may provide important information about the physiological accumulation of 123I-IIMU, which may be useful for the clinical diagnostic imaging of TP
Arc-like volcanic rocks from the southern Lancangjiang zone, SW China: Geochronological and geochemical constraints on their petrogenesis and tectonic implications
No full textJourney with Ting-Peng Liang in Pacific Asia Information Systems Field
No full textOur respectful old friend Professor Ting-Peng Liang (in short, TP) whom we loved suddenly passed away on May 20, 2021. But we cannot forget his smile and passion, and his inerasable footprints in PACIS, PAJAIS, and AIS Community. He was the founder of PACIS, founding editor-in-chief of PAJAIS, and past president of AIS to list just a few. He was the pioneer who received the first AIS Fellow and the first LEO Award from Asia Pacific. That is why the leaders of the information systems field organized the first ever special tribute session in PACIS 2021 in memory of TP (https://aisel.aisnet.org/pacis2021/253/
TP-model transformation-based-control design frameworks
No full textThis book covers new aspects and frameworks of control, design, and optimization based on the TP model transformation and its various extensions. The author outlines the three main steps of polytopic and LMI based control design: 1) development of the qLPV state-space model, 2) generation of the polytopic model; and 3) application of LMI to derive controller and observer. He goes on to describe why literature has extensively studied LMI design, but has not focused much on the second step, in part because the generation and manipulation of the polytopic form was not tractable in many cases. The author then shows how the TP model transformation facilitates this second step and hence reveals new directions, leading to powerful design procedures and the formulation of new questions. The chapters of this book, and the complex dynamical control tasks which they cover, are organized so as to present and analyze the beneficial aspect of the family of approaches (control, design, and optimization). Additionally, the book aims to convey simple TP modeling; a new convex hull manipulation based possibilities for optimization; a general framework for stability analysis; standardized modeling and system description; relaxed and universal LMI based design framework; and a gateway to time-delayed systems
Biochemical assessing SMDU-TP.
No full text(A) Representative TLC plate showing 32-PPP accumulations over 20–300 sec. time course when using 1.25 μCi/μL [γ-32P]-dTTP with 3000 (left side) and 1000 (right side) μM of dTTP (cold) as the substrate in the presence of 1 μM of SAMHD1 enzyme. (B) Graphing data from TLC analysis to generate slopes for the different dTTP concentrations tested. Data displayed as Product (μM) (y-axis) vs. Time (sec) (x-axis). Km of dTTP was calculated to be 845 ± 229 μM from the slopes generated using Prism software. (C) TLC analysis was done at various concentrations of dTTP (3000–30 μM) in the presence of various concentrations of SMDU-TP (1000–30 μM). Data are graphed as 1/V (μM/s) (y-axis) vs. 1/[dTTP] (μM) (x-axis). From the slopes generated, the Ki of SMDU-TP was calculated to be 256 ± 70 μM. (D) Biochemical HLPC analysis of reactions with and without SAMHD1, and in the presence of pppCH2dU or SMDU-TP analog is graphed. We observed that both pppCH2dU and SMDU-TP analogs inhibit SAMHD1’s activity ((p < 0.01) by one-way ANOVA analysis with Bonferroni’s multiple comparisons), leading to more dGTP substrate remaining after the 2 h incubation with enzyme. All data are representative of two independent studies with mean and SEM displayed.</p
LA-ICPMS zircon U-Pb dating for three Indosinian granitic plutons from central Hunan and western Guangdong provinces and its petrogenetic implications
No full textThe prediction theory of stationary random fields. III. Fourfold Wold decompositions
No full textAbstractIn this paper, we investigate various fourfold Wold-type decompositions of stationary random fields under different hypotheses of commutation properties. Spectral characterizations of the three multiplicities of the innovation subspaces are obtained. The equivalence relations between the weak commutation property, fourfold Wold-type decomposition, and quarter-plane moving average representation are proved. A complete spectral characterization of the weak commutation property is also given
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