Catalytic synthesis and enhanced Curie temperature of ε-Fe₃N@C nanostructure synthesized in a tetraethylenepentamine solution

Li, Yong,Pan, Desheng,Li, Da,Feng, Yang,Choi, C.J.,Liu, Wei,Zhang, Zhidong Elsevier 2018 Journal of magnetism and magnetic materials Vol.465 No.-

<P><B>Abstract</B></P> <P>ε-Fe<SUB>3</SUB>N@C nanocrystals without oxidation are one-pot synthesized by using the iron(II) acetylacetonate and tetraethylenepentamine (TEPA) as Fe and N precursors under a low temperature (533 K) in the presence of a small quantity of Pt atoms as the co-catalyst. The ε-Fe<SUB>3</SUB>N@C nanoparticles with a core-shell structure are nearly spherical and have a wide particle size distribution of 100–500 nm in diameter. Fe nanoparticles obtained by reduction of Fe<SUP>2+</SUP> with TEPA are an effective catalyzer for decomposing TEPA to produce N and C atoms at a temperature much lower than the boiling point of TEPA. The diffusion of N atoms into Fe nanoparticles for the formation of ε-Fe<SUB>3</SUB>N@C is proposed, based on the results obtained by kinetically controlling the synthetic temperature and surfactants. The ε-Fe<SUB>3</SUB>N@C nanoparticles have an excellent saturation magnetization of 135.5 emu/g at room temperature. A significantly enhanced Curie temperature (T<SUB>C</SUB>) of 614 K is reached in the present ε-Fe<SUB>3</SUB>N@C nanoparticles, which is much higher than the T<SUB>C</SUB> values in the previously reported ε-Fe<SUB>3</SUB>N<SUB>x</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Tetraethylenepentamine is proposed as a new N source to synthesize Fe nitride. </LI> <LI> Core-shelled ε-Fe<SUB>3</SUB>N@C nanoparticles are one-pot synthesized at 260 °C. </LI> <LI> Curie temperature of ε-Fe<SUB>3</SUB>N is significantly enhanced to 614 K. </LI> <LI> ε-Fe<SUB>3</SUB>N@C shows a high saturation magnetization of 135.5 emu/g at 300 K. </LI> </UL> </P>

C₂H <i>N</i> = 1 − 0 and N₂H⁺<i>J</i> = 1 − 0 observations of <i>Planck</i> Galactic cold clumps

Liu, X.-C.,Wu, Y.,Zhang, C.,Liu, T.,Yuan, J.,Qin, S.-L.,Ju, B.-G.,Li, L.-X. EDP Sciences 2019 Astronomy and astrophysics Vol.622 No.-

<P>A survey of C2H <I>N</I> = 1 − 0 and N2H<SUP>+</SUP><I>J</I> = 1 − 0 toward <I>Planck</I> Galactic cold clumps (PGCCs) was performed using the Purple Mountain Observatory’s 13.7 m telescope. C2H and N2H<SUP>+</SUP> were chosen to study the chemical evolutionary states of PGCCs. Among 121 observed molecular cores associated with PGCCs, 71 and 58 are detected with C2H <I>N</I> = 1 − 0 and N2H<SUP>+</SUP><I>J</I> = 1 − 0, respectively. The detected lines of most sources can be fitted with a single component with compatible <I>V</I>LSR and line widths, which confirms that these PGCC cores are very cold (with gas temperatures 9-21 K) and quiescent while still dominanted by turbulence. The ratio between the column densities of C2H and N2H<SUP>+</SUP> (<I>N</I>(C2H)/<I>N</I>(N2H<SUP>+</SUP>)) is found to be a good tracer for the evolutionary states of PGCC cores. Gas-grain chemical model can reproduce the decreasing trend of <I>N</I>(C2H)/<I>N</I>(N2H<SUP>+</SUP>) as a function of time. The cores with the lowest abundances of N2H<SUP>+</SUP> (<I>X</I>[N2H<SUP>+</SUP>] < 10<SUP>−10</SUP>) are the youngest, and have nearly constant abundances of C2H. In evolved cores with <I>X</I>[N2H<SUP>+</SUP>] ~10<SUP>−9</SUP>, abundances of C2H drop quickly as the exhaustion of carbon atoms. Although these PGCC cores are in different evolutionary states, they are all quite young (< 5 × 10<SUP>5</SUP> yr) with <I>N</I>(C2H) > <I>N</I>(N2H<SUP>+</SUP>). Mapping observations are carried out toward 20 PGCC cores. The PGCC cores in Cepheus have lower <I>N</I>(C2H)/<I>N</I>(N2H<SUP>+</SUP>) and larger line widths compared with those in Taurus. This implies that PGCC cores in Taurus are less chemically evolved than those in Cepheus.</P>

Impact of low dose atorvastatin on development of new-onset diabetes mellitus in Asian population: Three-year clinical outcomes

Park, J.Y.,Rha, S.W.,Choi, B.,Choi, J.W.,Ryu, S.K.,Kim, S.,Noh, Y.K.,Choi, S.Y.,Akkala, R.G.,Li, H.,Ali, J.,Xu, S.,Ngow, H.A.,Lee, J.J.,Lee, G.N.,Kim, J.,Lee, S.,Na, J.O.,Choi, C.U.,Lim, H.E.,Kim, J.W Elsevier/North-Holland Biomedical Press 2015 INTERNATIONAL JOURNAL OF CARDIOLOGY Vol.184 No.-

Background: High dose atorvastatin is known to be associated with new onset diabetes mellitus (NODM) in patients with high risk for developing diabetes mellitus (DM). However, low dose atorvastatin is more commonly used as compared with high dose atorvastatin. The aim of this study is to investigate the impact of low dose atorvastatin (LDA, 10mg or 20mg) on the development of NODM up to three years in Asian patients. Methods: From January 2004 to September 2009, we investigated a total of 3566 patients who did not have DM. To adjust for potential confounders, a propensity score matching (PSM) analysis was performed using the logistic regression model. After PSM (C-statistics: 0.851), a total of 818 patients (LDA group, n=409 patients and control group, n=409 patients) were enrolled for analysis. Results: Before PSM, the cumulative incidence of NODM (5.8% vs. 2.1%, p<0.001), myocardial infarction (0.5% vs. 0.1%, p-value=0.007), and major adverse cardio-cerebral event (MACCE, 1.8% vs. 0.7%, p-value=0.012) at three-years were higher in the LAD group. However, after PSM, there was a trend toward higher incidence of NODM (5.9% vs. 3.2%, p=0.064) in the LDA group, but the incidence of MACCE (1.2% vs. 1.5%, p-value=1.000) was similar between the two groups. In multivariable analysis, the LDA administration was tended to be an independent predictor of NODM (OR: 1.99, 95% CI: 1.00-3.98, p-value 0.050). Conclusions: In this study, the use of LDA tended to be a risk factor for NODM in Asian patients and reduced clinical events similar to the control group. However, large-scale randomized controlled trials will be needed to get the final conclusion.

SEARCHES FOR MILLISECOND PULSAR CANDIDATES AMONG THE UNIDENTIFIED<i>FERMI</i>OBJECTS

Hui, C. Y.,Park, S. M.,Hu, C. P.,Lin, L. C. C.,Li, K. L.,Kong, A. K. H.,Tam, P. H. T.,Takata, J.,Cheng, K. S.,Jin, Ruolan,Yen, T.-C.,Kim, Chunglee IOP Publishing 2015 The Astrophysical journal Vol.809 No.1

<P>Here we report the results of searching millisecond pulsar (MSP) candidates from the Fermi LAT second source catalog (2FGL). Seven unassociated gamma-ray sources in this catalog are identified as promising MSP candidates based on their gamma-ray properties. Through the X-ray analysis, we have detected possible X-ray counterparts, localized to an arcsecond accuracy. We have systematically estimated their X-ray fluxes and compared them with the corresponding gamma-ray fluxes. The X-ray to gamma-ray flux ratios for 2FGL J1653.6-0159 and 2FGL J1946.4-5402 are comparable with the typical value for pulsars. For 2FGL J1625.2-0020, 2FGL J1653.6-0159, and 2FGL J1946.4-5402, their candidate X-ray counterparts are bright enough to perform a detailed spectral and temporal analysis to discriminate their thermal/non-thermal nature and search for the periodic signal. We have also searched for possible optical/IR counterparts at the X-ray positions. For the optical/IR source coincident with the brightest X-ray object associated with 2FGL J1120.0-2204, its spectral energy distribution is comparable with a late-type star. Evidence for the variability has also been found by examining its optical light curve. All the aforementioned 2FGL sources resemble a pulsar in one or more aspects, making them promising targets for follow-up investigations.</P>

DISCOVERY OF X-RAY PULSATIONS FROM THE NEXT GEMINGA, PSR J1836+5925

Lin, L. C. C.,Hui, C. Y.,Li, K. T.,Takata, J.,Hu, C. P.,Kong, A. K. H.,Yen, D. C. C.,Chou, Y. IOP Publishing 2014 ASTROPHYSICAL JOURNAL LETTERS - Vol.793 No.1

<P>We report recent XMM-Newton investigations of PSR J1836+5925, the 'next Geminga,' which determined an X-ray pulsation of similar to 173.3 ms. Its X-ray periodicity is consistent with the gamma-ray ephemeris at the same epoch. The X-ray folded light curve has a sinusoidal structure that is different from the double-peaked gamma-ray pulse profile. We have also analyzed the X-ray phase-averaged spectra which shows that the X-ray emission from PSR J1836+5925 is thermal dominant. This suggests that the X-ray pulsation mainly originates from the modulated hot spot on the stellar surface.</P>

Five-year clinical outcomes in patients with significant coronary artery spasm: A propensity score-matched analysis

Choi, B.G.,Park, S.H.,Rha, S.W.,Park, J.Y.,Choi, S.Y.,Park, Y.,Xu, S.,Ngow, H.A.,Ali, J.,Li, H.,Kim, J.B.,Lee, S.,Na, J.O.,Choi, C.U.,Lim, H.E.,Kim, J.W.,Kim, E.J.,Park, C.G.,Seo, H.S.,Oh, D.J. Elsevier/North-Holland Biomedical Press 2015 INTERNATIONAL JOURNAL OF CARDIOLOGY Vol.184 No.-

Background: Coronary artery spasm (CAS) is known to be a risk factor of acute coronary syndrome and angina pectoris. However, there is no currently available data with larger study population regarding long-term clinical outcomes of CAS in real world clinical practice. Objectives: We evaluated the prevalence of CAS and the impact of CAS on 5-year clinical outcomes in a series of Asian CAS patients documented by intracoronary acetylcholine (Ach) provocation test. Methods: A total of 1413 consecutive patients without significant coronary artery disease (CAD) who underwent Ach provocation test between Nov. 2004 and Oct. 2008 were enrolled. Significant CAS was defined as >70% of narrowing by incremental intracoronary injection of 20, 50 and 100μg. Patients were divided into two groups based on the presence of significant CAS (the non-CAS group: n=640, the CAS group; n=773). To adjust potential confounders, a propensity score matched (PSM) analysis was performed using the logistic regression model. Results: A total of 54.7% (773/1413) patients were diagnosed as CAS documented by Ach provocation test. After PSM analysis, 2 propensity-matched groups (451 pairs, n=902, C-statistic=0.677) were generated. Despite of similar incidence of individual hard endpoints including mortality, myocardial infarction and revascularization, the CAS group showed the higher trend of recurrent angina requiring follow up angiography than the non-CAS group up to 5years (HR; 1.56, 95% C.I.; 0.99-2.46, p=0.054). Conclusions: The prevalence of CAS was 54.7%. Although the cumulative incidence of recurrent angina requiring follow up coronary angiography seems to be increased up to 5years in CAS patients, CAS patients was not associated with major individual and composite clinical outcomes such as mortality, MI, PCI, CVA with optimal medical therapy as compared with patients without CAS.

Polymorphisms in the Promoter Region of the Chinese Bovine PPARGC1A Gene

Li, M.J.,Liu, M.,Liu, D.,Lan, X.Y.,Lei, C.Z.,Yang, D.Y.,Chen, H. Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.4

The peroxisome proliferator-activated receptor gamma coactivator-1 alpha protein, encoded by the PPARGC1A gene, plays an important role in energy homeostasis. The genetic variations within the PPARGC1A gene promoter region were scanned in 808 Chinese native bovines belonging to three cattle breeds and yaks. A total of 6 SNPs and one 4 bp insertion variation in the promoter region of the bovine PPARGC1A gene were identified: SNP -259 T>A, -301_-298insCTTT, -915 A>G, -1175 T>G, -1590 C>T, -1665 C>T and -1690 G>A, which are in the binding sites of some important transcription factors: sex-determining region Y (SRY), myeloid-specific zinc finger-1 (MZF-1) and octamer factor 1(Oct-1). It is expected that these polymorphisms may regulate PPARGC1A gene transcription and might have consequences at a regulatory level.

J-Sim: a simulation and emulation environment for wireless sensor networks

Sobeih, A.,Hou, J.C.,Lu-Chuan Kung,Ning Li,Honghai Zhang,Wei-Peng Chen,Hung-Ying Tyan,Hyuk Lim IEEE 2006 IEEE wireless communications Vol.13 No.4

<P>Wireless sensor networks have gained considerable attention in the past few years. They have found application domains in battlefield communication, homeland security, pollution sensing, and traffic monitoring. As such, there has been an increasing need to define and develop simulation frameworks for carrying out high-fidelity WSN simulation. In this article we present a modeling, simulation, and emulation framework for WSNs in J-Sim - an open source, component-based compositional network simulation environment developed entirely in Java. This framework is built on the autonomous component architecture and extensible internetworking framework of J-Sim, and provides an object-oriented definition of target, sensor, and sink nodes, sensor and wireless communication channels, and physical media such as seismic channels, mobility models, and power models (both energy-producing and energy-consuming components). Application-specific models can be defined by subclassing classes in the simulation framework and customizing their behaviors. We also include in J-Sim a set of classes and mechanisms to realize network emulation. We demonstrate the use of the proposed WSN simulation framework by implementing several well-known localization, geographic routing, and directed diffusion protocols, and perform performance comparisons (in terms of the execution time incurred and memory used) in simulating WSN scenarios in J-Sim and ns-2. The simulation study indicates the WSN framework in J-Sim is much more scalable than ns-2 (especially in memory usage). We also demonstrate the use of the WSN framework in carrying out real-life full-fledged Future Combat System (FCS) simulation and emulation</P>

<i>Swift</i>,<i>XMM</i>-<i>Newton</i>, and<i>NuSTAR</i>Observations of PSR J2032+4127/MT91 213

Li, K. L.,Kong, A. K. H.,Tam, P. H. T.,Hou, X.,Takata, J.,Hui, and C. Y. American Astronomical Society 2017 The Astrophysical journal Vol.843 No.2

<P>We report our recent Swift, NuSTAR, and XMM-Newton X-ray and Lijiang optical observations on PSR J2032 + 4127/MT91 213, the gamma-ray binary candidate with a period of 45-50 years. The coming periastron of the system was predicted to be in 2017 November, around which high-energy flares from keV to TeV are expected. Recent studies with Chandra and Swift X-ray observations taken in 2015/2016 showed that its X-ray emission has been brighter by a factors of similar to 10 than that before 2013, probably revealing some ongoing activities between the pulsar wind and the stellar wind. Our new Swift/XRT lightcurve shows no strong evidence of a single vigorous brightening trend, but rather several strong X-ray flares on weekly to monthly timescales with a slowly brightening baseline, namely the low state. The NuSTAR and XMM-Newton observations taken during the flaring and the low states, respectively, show a denser environment and a softer power-law index during the flaring state, implying that the pulsar wind interacted with the stronger stellar winds of the companion to produce the flares. These precursors would be crucial in studying the predicted giant outburst from this extreme gamma-ray binary during the periastron passage in late 2017.</P>

Effect of Alcohol Fermented Feed on Lactating Performance, Blood Metabolites, Milk Fatty Acid Profile and Cholesterol Content in Holstein Lactating Cows

Li, X.Z.,Park, B.K.,Yan, C.G.,Choi, J.G.,Ahn, J.S.,Shin, J.S. Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.11

A feeding experiment with 40 lactating Holstein cows and 4 dietary treatments was conducted to investigate supplementation with different levels of alcohol fermented feed to the TMR on lactating performance, blood metabolites, milk fatty acid profile and cholesterol concentration of blood and milk. Forty Holstein lactating cows ($106{\pm}24$ d post-partum; mean${\pm}$SD) were distributed into four groups and randomly assigned to one of four treatments with each containing 10 cows per treatment. The treatment supplemented with TMR (DM basis) as the control (CON), and CON mixed with alcohol-fermented feeds (AFF) at a level of 5%, 10% and 15% of the TMR as T1, T2 and T3, respectively. Dry matter intake and milk yield were not affected by supplementation of AFF. An increased 4% FCM in the milk occurred in cows fed T3 diet compared with CON, while T1 and T2 diets decreased 4% FCM in a dose dependent manner. Supplementation of AFF increased the concentration of albumin, total protein (TP), ammonia, and high density lipoprotein-cholesterol in serum compared with CON. In contrast, supplementation with AFF clearly decreased concentration of blood urea nitrogen (BUN) and total cholesterol (TC) compare with CON. AFF supplementation increased the proportion of C18:1n9 and C18:2n6 compared to CON. A decrease in the concentration of saturated fatty acid (SFA) for T1, T2 and T3 resulted in an increased unsaturated fatty acid (USFA) to SFA ratio compared to CON. Concentration of cholesterol in milk fat was reduced in proportion to the supplemental level of AFF. Feeding a diet supplemented with a moderate level AFF to lactating cows could be a way to alter the feed efficiency and fatty acid profile of milk by increasing potentially human consumer healthy fatty acid without detrimental effects on feed intake and milk production. A substantially decreased cholesterol proportion in milk induced by supplementation AFF suggests that alcohol fermented feed may improve milk cholesterol levels without any negative effects in lactating cows.