bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification and Characterization of Phenylpropanoid Biosynthetic Genes and Their Accumulation in Bitter Melon (Momordica charantia)
Authors: Cuong Do Manh , Kwon Soon-Jae , Jeon Jin , Park Yun Ji , Park Jong Seok , Park Sang Un
Published: February 2018

Phenylpropanoids and flavonoids belong to a large group of secondary metabolites, and are considered to have antioxidant activity, which protects the cells against biotic and abiotic stresses. However, the accumulation of phenylpropanoids and flavonoids in bitter melon has rarely been studied. Here, we identify ten putative phenylpropanoid and flavonoid biosynthetic genes in bitter melon. Most genes were highly expressed in leaves and/or flowers. HPLC analysis showed that rutin and epicatechin were the most abundant compounds in bitter melon. Rutin content was the highest in leaves, whereas epicatechin was highly accumulated in flowers and fruits. The accumulation patterns of trans-cinnamic acid, p-coumaric acid, ferulic acid, kaempferol, and rutin coincide with the expression patterns of McPAL, McC4H, McCOMT, McFLS, and Mc3GT, respectively, suggesting that these genes play important roles in phenylpropanoid and flavonoid biosynthesis in bitter melon. In addition, we also investigated the optimum light conditions for enhancing phenylpropanoid and flavonoid biosynthesis and found that blue light was the most effective wavelength for enhanced accumulation of phenylpropanoids and flavonoids in bitter melon.
Stable Value Funds Performance
Authors: Babbel David , Herce Miguel
Published: February 2018

Little in the scholarly economics literature is directed specifically to the performance of stable value funds, although they occupy a leading place among retirement investment vehicles. They are currently offered in more than one-third of all defined contribution plans in the USA, with more than $800 billion of assets under management. This paper rigorously examines their performance throughout the entire period since their inception in 1973. We produce a composite index of stable value returns. We next conduct mean-variance analysis, Sharpe and Sortino ratio analysis, stochastic dominance analysis, and optimal multi-period portfolio composition analysis. Our evidence suggests that stable value funds dominate (on average) two major asset classes based on a historical analysis, and that they often occupy a significant position in optimized portfolios across a broad range of risk aversion levels. We discuss factors that contributed to stable value funds’ past performance and whether they can continue to perform well into the future. We also discuss considerations regarding whether or not to include stable value as an element in target date funds within defined contribution pension plans.
Active Prior Tactile Knowledge Transfer for Learning Tactual Properties of New Objects
Authors: Feng Di , Kaboli Mohsen , Cheng Gordon
Published: February 2018

Reusing the tactile knowledge of some previously-explored objects (prior objects) helps us to easily recognize the tactual properties of new objects. In this paper, we enable a robotic arm equipped with multi-modal artificial skin, like humans, to actively transfer the prior tactile exploratory action experiences when it learns the detailed physical properties of new objects. These experiences, or prior tactile knowledge, are built by the feature observations that the robot perceives from multiple sensory modalities, when it applies the pressing, sliding, and static contact movements on objects with different action parameters. We call our method Active Prior Tactile Knowledge Transfer (APTKT), and systematically evaluated its performance by several experiments. Results show that the robot improved the discrimination accuracy by around

10
%

when it used only one training sample with the feature observations of prior objects. By further incorporating the predictions from the observation models of prior objects as auxiliary features, our method improved the discrimination accuracy by over

20
%

. The results also show that the proposed method is robust against transferring irrelevant prior tactile knowledge (negative knowledge transfer).
Robust Rate Maximization for Heterogeneous Wireless Networks under Channel Uncertainties
Authors: Xu Yongjun , Hu Yuan , Li Guoquan
Published: February 2018

Heterogeneous wireless networks are a promising technology in next generation wireless communication networks, which has been shown to efficiently reduce the blind area of mobile communication and improve network coverage compared with the traditional wireless communication networks. In this paper, a robust power allocation problem for a two-tier heterogeneous wireless networks is formulated based on orthogonal frequency-division multiplexing technology. Under the consideration of imperfect channel state information (CSI), the robust sum-rate maximization problem is built while avoiding sever cross-tier interference to macrocell user and maintaining the minimum rate requirement of each femtocell user. To be practical, both of channel estimation errors from the femtocells to the macrocell and link uncertainties of each femtocell user are simultaneously considered in terms of outage probabilities of users. The optimization problem is analyzed under no CSI feedback with some cumulative distribution function and partial CSI with Gaussian distribution of channel estimation error. The robust optimization problem is converted into the convex optimization problem which is solved by using Lagrange dual theory and subgradient algorithm. Simulation results demonstrate the effectiveness of the proposed algorithm by the impact of channel uncertainties on the system performance.
Melioidosis in Sri Lanka
Authors: Corea Enoka M. , De Silva Aruna Dharshan , Thevanesam Vasanthi
Published: February 2018

Until recently, Sri Lanka was not considered a country with endemic melioidosis. However, an increasing number of cases is being reported. National surveillance for melioidosis was instituted after 2008. A total of 250 culture-positive cases was recorded between 2006 and May 2017. Males predominated (71.6%). The age range was wide (2–92 years) reflecting a ubiquity of exposure. The majority (201/250, 80%) lived in rural areas. All provinces were affected. Case load increased during the two monsoonal periods (67%). There was representation of every population group including farmers (n = 44), housewives (n = 24), school children (n = 10), professionals (n = 5), businesspersons (n = 6), white-collar workers (n = 10) and blue-collar workers (n = 8). Diabetes was the predominant risk factor (n = 163, 65.2%). Clinical presentations included community-acquired sepsis and pneumonia, superficial and deep abscesses, and septic arthritis. Mortality was 20.4% (51/250). A majority (n = 212) of isolates belonged to the YLF (Yersinia-like fimbrial) clade but 38 were BTFC (B. thailandensis-like flagellum and chemotaxis). A total of 108 isolates was genotyped and 46 sequence types (STs) were identified, 40 being novel. It is clear that melioidosis is endemic in Sri Lanka with a wide geographic and demographic distribution. There is an urgent need to extend surveillance of melioidosis to under-resourced parts of the country and to populations at high risk.
Stellar Multiplicity Meets Stellar Evolution and Metallicity: The APOGEE View
Authors: Badenes Carles , Mazzola Christine , Thompson Todd A. , Covey Kevin , Freeman Peter E. , Walker Matthew G. , Moe Maxwell , Troup Nicholas , Nidever David , Prieto Carlos Allende , Andrews Brett , Barbá Rodolfo H. , Beers Timothy C. , Bovy Jo , Carlberg Joleen K. , Lee Nathan De , Johnson Jennifer , Lewis Hannah , Majewski Steven R. , Pinsonneault Marc , Sobeck Jennifer , Stassun Keivan G. , Stringfellow Guy S. , Zasowski Gail
Published: February 2018

We use the multi-epoch radial velocities acquired by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey to perform a large-scale statistical study of stellar multiplicity for field stars in the Milky Way, spanning the evolutionary phases between the main sequence (MS) and the red clump. We show that the distribution of maximum radial velocity shifts (ΔRVmax) for APOGEE targets is a strong function of log g, with MS stars showing ΔRVmax as high as ∼300

, and steadily dropping down to ∼30

for log g ∼ 0, as stars climb up the red giant branch (RGB). Red clump stars show a distribution of ΔRVmax values comparable to that of stars at the tip of the RGB, implying they have similar multiplicity characteristics. The observed attrition of high ΔRVmax systems in the RGB is consistent with a lognormal period distribution in the MS and a multiplicity fraction of 0.35, which is truncated at an increasing period as stars become physically larger and undergo mass transfer after Roche Lobe overflow during H-shell burning. The ΔRVmax distributions also show that the multiplicity characteristics of field stars are metallicity-dependent, with metal-poor ([Fe/H] ≲ −0.5) stars having a multiplicity fraction a factor of 2–3 higher than metal-rich ([Fe/H] ≳ 0.0) stars. This has profound implications for the formation rates of interacting binaries observed by astronomical transient surveys and gravitational wave detectors, as well as the habitability of circumbinary planets.
Curvature from Strong Gravitational Lensing: A Spatially Closed Universe or Systematics?
Authors: Li Zhengxiang , Ding Xuheng , Wang Guo-Jian , Liao Kai , Zhu Zong-Hong
Published: February 2018

Model-independent constraints on the spatial curvature are not only closely related to important problems, such as the evolution of the universe and properties of dark energy, but also provide a test of the validity of the fundamental Copernican principle. In this paper, with the distance sum rule in the Friedmann–Lemaître–Robertson–Walker metric, we achieve model-independent measurements of the spatial curvature from the latest type Ia supernovae and strong gravitational lensing (SGL) observations. We find that a spatially closed universe is preferred. Moreover, by considering different kinds of velocity dispersion and subsamples, we study possible factors that might affect model-independent estimations for the spatial curvature from SGL observations. It is suggested that the combination of observational data from different surveys might cause a systematic bias, and the tension between the spatially flat universe and SGL observations is alleviated when the subsample only from the Sloan Lens ACS Survey is used or a more complex treatment for the density profile of lenses is considered.
The Luminous X-Ray Halos of Two Compact Elliptical Galaxies
Authors: Buote David A. , Barth Aaron J.
Published: February 2018

There is mounting evidence that compact elliptical galaxies (CEGs) are local analogs of the high-redshift “red nuggets” that are thought to represent progenitors of today’s early-type galaxies (ETGs). We report the discovery of extended X-ray emission from a hot interstellar/intragroup medium in two CEGs, Mrk 1216 and PGC 032873, using shallow Chandra observations. We find that PGC 032873 has an average gas temperature of k

B

T = 0.67 ± 0.06 keV within a radius of 15 kpc and a luminosity L
x = (1.8 ± 0.2) × 1041 erg s−1 within a radius of 100 kpc. For Mrk 1216, which is closer and more luminous (L
x(<100 kpc) = (12.1 ± 1.9) × 1041 erg s−1), we used an entropy-based hydrostatic equilibrium (HE) procedure and obtained a good constraint on the H-band stellar mass-to-light ratio, M
stars/L

H
 = 1.33 ± 0.21 solar, that is in good agreement with stellar dynamical (SD) studies, which supports the HE approximation. We obtain a density slope of 2.22 ± 0.08 within R

e
that is consistent with other CEGs and normal local ETGs, while the dark matter fraction within R

e
, f
DM = 0.20 ± 0.07 is similar to local ETGs. We constrain the supermasssive black hole mass, M
BH = (5 ± 4) × 109
M
⊙, with M
BH > 1.4 × 1010
M
⊙ (90% confidence), which is consistent with a recent SD measurement. We obtain a halo concentration (c
200 = 17.5 ± 6.7) and mass (M
200 = (9.6 ± 3.7) × 1012
M
⊙), where c
200 exceeds the mean ΛCDM value (≈7), which is consistent with a system that formed earlier than the general halo population. We suggest that these galaxies should be classified as fossil groups.
Chemical Abundances in the Leading Arm of the Magellanic Stream∗
Authors: Fox Andrew J. , Barger Kathleen A. , Wakker Bart P. , Richter Philipp , Antwi-Danso Jacqueline , Casetti-Dinescu Dana I. , Howk J. Christopher , Lehner Nicolas , D’Onghia Elena , Crowther Paul A. , Lockman Felix J.
Published: February 2018

The Leading Arm (LA) of the Magellanic Stream is a vast debris field of H i clouds connecting the Milky Way and the Magellanic Clouds. It represents an example of active gas accretion onto the Galaxy. Previously, only one chemical abundance measurement had been made in the LA. Here we present chemical abundance measurements using Hubble Space Telescope/Cosmic Origins Spectrograph and Green Bank Telescope spectra of four AGN sightlines passing through the LA and three nearby sightlines that may trace outer fragments of the LA. We find low oxygen abundances, ranging from

solar to

solar, in the confirmed LA directions, with the lowest values found in the region known as LA III, farthest from the LMC. These abundances are substantially lower than the single previous measurement, S/H = 35 ± 7% solar, but are in agreement with those reported in the SMC filament of the trailing Stream, supporting a common origin in the SMC (not the LMC) for the majority of the LA and trailing Stream. This provides important constraints for models of the formation of the Magellanic System. Finally, two of the three nearby sightlines show high-velocity clouds with H i columns, kinematics, and oxygen abundances consistent with LA membership. This suggests that the LA is larger than traditionally thought, extending at least 20° further to the Galactic northwest.
On the Gas Content and Efficiency of AGN Feedback in Low-redshift Quasars
Authors: Shangguan Jinyi , Ho Luis C. , Xie Yanxia
Published: February 2018

The interstellar medium is crucial to understanding the physics of active galaxies and the coevolution between supermassive black holes and their host galaxies. However, direct gas measurements are limited by sensitivity and other uncertainties. Dust provides an efficient indirect probe of the total gas. We apply this technique to a large sample of quasars, whose total gas content would be prohibitively expensive to measure. We present a comprehensive study of the full (1 to 500 μm) infrared spectral energy distributions of 87 redshift <0.5 quasars selected from the Palomar-Green sample, using photometric measurements from 2MASS, WISE, and Herschel, combined with Spitzer mid-infrared (5–40 μm) spectra. With a newly developed Bayesian Markov Chain Monte Carlo fitting method, we decompose various overlapping contributions to the integrated spectral energy distribution, including starlight, warm dust from the torus, and cooler dust on galaxy scales. This procedure yields a robust dust mass, which we use to infer the gas mass, using a gas-to-dust ratio constrained by the host galaxy stellar mass. Most (90%) quasar hosts have gas fractions similar to those of massive, star-forming galaxies, although a minority (10%) seem genuinely gas-deficient, resembling present-day massive early-type galaxies. This result indicates that “quasar mode” feedback does not occur or is ineffective in the host galaxies of low-redshift quasars. We also find that quasars can boost the interstellar radiation field and heat dust on galactic scales. This cautions against the common practice of using the far-infrared luminosity to estimate the host galaxy star formation rate.
The Spectral Energy Distribution of the Hyperluminous, Hot Dust-obscured Galaxy W2246–0526
Authors: Fan Lulu , Gao Ying , Knudsen Kirsten K. , Shu Xinwen
Published: February 2018

Hot dust-obscured galaxies (Hot DOGs) are a luminous, dust-obscured population recently discovered in the WISE All-Sky survey. Multiwavelength follow-up observations suggest that they are mainly powered by accreting supermassive black holes (SMBHs), lying in dense environments, and being in the transition phase between extreme starburst and UV-bright quasars. Therefore, they are good candidates for studying the interplay between SMBHs, star formation, and environment. W2246−0526 (hereafter, W2246), a Hot DOG at z ∼ 4.6, has been taken as the most luminous galaxy known in the universe. Revealed by the multiwavelength images, the previous Herschel SPIRE photometry of W2246 is contaminated by a foreground galaxy (W2246f), resulting in an overestimation of its total IR luminosity by a factor of about two. We perform the rest-frame UV/optical-to-far-IR spectral energy distribution (SED) analysis with SED3FIT and re-estimate its physical properties. The derived stellar mass

makes it among the most massive galaxies with spectroscopic redshift z > 4.5. Its structure is extremely compact and requires an effective mechanism to puff-up. Most of (>95%) its IR luminosity is from AGN torus emission, revealing the rapid growth of the central SMBH. We also predict that W2246 may have a significant molecular gas reservoir based on the dust mass estimation.
Simulations of Core-collapse Supernovae in Spatial Axisymmetry with Full Boltzmann Neutrino Transport
Authors: Nagakura Hiroki , Iwakami Wakana , Furusawa Shun , Okawa Hirotada , Harada Akira , Sumiyoshi Kohsuke , Yamada Shoichi , Matsufuru Hideo , Imakura Akira
Published: February 2018

We present the first results of our spatially axisymmetric core-collapse supernova simulations with full Boltzmann neutrino transport, which amount to a time-dependent five-dimensional (two in space and three in momentum space) problem. Special relativistic effects are fully taken into account with a two-energy-grid technique. We performed two simulations for a progenitor of 11.2 M
☉, employing different nuclear equations of state (EOSs): Lattimer and Swesty’s EOS with the incompressibility of K = 220 MeV (LS EOS) and Furusawa’s EOS based on the relativistic mean field theory with the TM1 parameter set (FS EOS). In the LS EOS, the shock wave reaches ∼700 km at 300 ms after bounce and is still expanding, whereas in the FS EOS it stalled at ∼200 km and has started to recede by the same time. This seems to be due to more vigorous turbulent motions in the former during the entire postbounce phase, which leads to higher neutrino-heating efficiency in the neutrino-driven convection. We also look into the neutrino distributions in momentum space, which is the advantage of the Boltzmann transport over other approximate methods. We find nonaxisymmetric angular distributions with respect to the local radial direction, which also generate off-diagonal components of the Eddington tensor. We find that the rθ component reaches ∼10% of the dominant rr component and, more importantly, it dictates the evolution of lateral neutrino fluxes, dominating over the θθ component, in the semitransparent region. These data will be useful to further test and possibly improve the prescriptions used in the approximate methods.
Massive Outflows Associated with ATLASGAL Clumps
Authors: Yang A. Y. , Thompson M. A. , Urquhart J. S. , Tian W. W.
Published: February 2018

We have undertaken the largest survey for outflows within the Galactic plane using simultaneously observed

and

data. Out of a total of 919 ATLASGAL clumps, 325 have data suitable to identify outflows, and 225 (69% ± 3%) show high-velocity outflows. The clumps with detected outflows show significantly higher clump masses (

), bolometric luminosities (

), luminosity-to-mass ratios (

), and peak H2 column densities (

) compared to those without outflows. Outflow activity has been detected within the youngest quiescent clump (i.e.,

weak) in this sample, and we find that the outflow detection rate increases with

,

,

, and

, approaching 90% in some cases (UC H ii regions = 93% ± 3%; masers = 86% ± 4%; HC H ii regions = 100%). This high detection rate suggests that outflows are ubiquitous phenomena of massive star formation (MSF). The mean outflow mass entrainment rate implies a mean accretion rate of

, in full agreement with the accretion rate predicted by theoretical models of MSF. Outflow properties are tightly correlated with

,

, and

and show the strongest relation with the bolometric clump luminosity. This suggests that outflows might be driven by the most massive and luminous source within the clump. The correlations are similar for both low-mass and high-mass outflows over 7 orders of magnitude, indicating that they may share a similar outflow mechanism. Outflow energy is comparable to the turbulent energy within the clump; however, we find no evidence that outflows increase the level of clump turbulence as the clumps evolve. This implies that the origin of turbulence within clumps is fixed before the onset of star formation.
Epidemiology of multi drug resistant organisms in pigs in Lebanon
Authors: Dandachi Iman , Fayad Elie , El-Bazzal Bassel , Sleiman Ahmad , Rolain Jean-marc , Daoud Ziad
Published: February 2018

Introduction: Livestock are nowadays considered potent reservoirs of multi drug resistance. Enteric resistant organisms in animals can be transmitted to humans and be causative agents of infections with therapeutic challenges. The aim of this study is to determine the prevalence of multi drug resistant organisms in Lebanese swine farms.

Methodology: In May 2017, 94 fecal samples were collected from pigs in the south of Lebanon. Three media supplemented with cefotaxime, ertapenem, colistin were used for the screening of ESBL, carbapenemase producers and colistin resistance respectively. MALDI-TOF was used for bacterial identification. Double disk synergy test, ampC disk test and carpa np test were used for the detection of ESBL, ampC and carbapenemase producers respectively. RT-PCR was performed for the screening of beta lactamase and mcr colistin resistance genes.

Results: 77/94 fecal samples, showed growth on the medium supplemented with cefotaxime. In total 111 strains were isolated: 94% were identified as E.coli, 6% other organisms such as E. fergusonii and K. pneumoniae. Phenotypic tests showed that 72% of isolated strains were ESBL producers while 28% were ampC beta lactamase producers. RT-PCR analysis revealed that blaCTX-M was present in 45% of isolated strains, blaTEM in 26% and blaSHV in 10%. In parallel, 22 colistin resistant E.coli strains and 1 K.pneumoniae carrying mcr-1 were isolated.

Conclusions: This study showed the importance of swine farms as reservoirs of resistance in Lebanon. The emergence of colistin resistance in pigs is worrying. A re-evaluation of antibiotic consumption in pigs is therefore warranted.
Multi Drug resistant Organisms in Chicken farms and their Surrounding Environment
Authors: Dandachi Iman , Fayad Elie , El-Bazzal Bassel , Sleiman Ahmad , Rolain Jean-Marc , Daoud Ziad
Published: February 2018

Background: Chicken farms are nowadays regarded as reservoirs of multi-drug resistance. Studies have shown that resistant organisms can be readily transferred from animals to their surrounding ecosystem. The aim of this study is to determine if any link exists between the prevalence of multi-drug resistance in chicken farms and their surrounding environment.

 

Material/methods: In May-2017, 200 fecal swabs were collected from a chicken farm in Lebanon. Fecal samples from six workers and 41 environmental samples surrounding the farm were also taken. Three different selective media were used for the screening of multi-drug resistant and colistin resistant organisms. MALDI-TOF was used for bacterial identification. Double disk synergy test and ampC disk test were used for the screening of ESBL and ampC producers respectively. Furthermore, RT-PCR was performed for the detection of beta lactamase and mcr colistin resistance genes.

 

Results: In chicken, 315 E.coli strains were isolated: 53% were ESBL/ampC co-producers, 27% ampC and 42.5% mcr-1 positive isolates. Furthermore, 29 K.pneumoniae harboring mcr-1 were also isolated. In workers, ESBL producing E.coli were detected in 4/6 workers whereas mcr-1 carrying E.coli were detected in all workers. In the environment, ESBLs and mcr-1 positives were detected in 95% and 7% of the samples respectively. RT-PCR revealed the detection of B-lactamase genes in all samples at different rates.  

Conclusions: This study showed a relatively high prevalence of ESBL and mcr-1 positive isolates in chicken and their environment. MLST is in progress to determine if any link exists between multi-drug resistant organisms in these ecosystems investigated.
Genotyping of Mycobacterium tuberculosis in Lebanon using a novel rapid spoligotyping multiplex luminex method
Authors: Massoud Khaldoun , Araj George F , Fadlallah Sukayna , Reslan Lina , Itani Lina , Avedissian Aline , Dbaibo Ghassan , Saade Antoine , Matar Ghassan M
Published: February 2018

Introduction: Incidence of Tuberculosis (TB) in Lebanon, according to the WHO, is estimated to be 35 cases per 100,000 people. However, data about the genotypes of circulating Mycobacterium tuberculosis isolates (MTB) in this country is lacking. This study aims to reveal the genotypes of TB isolates recovered from patients in Lebanon.

Methodology: Fifty M. tuberculosis isolates from patients in Lebanon were recovered and identified at the reference TB center of the Ministry of Public Health. All isolates were heat killed and subjected to DNA extraction. Spoligotyping method (TB-Spol, Beamedex, France) was used to identify the presence of 43 spacers via a multi-analyte profiling system (Luminex, Bio-Rad). Generated patterns were assigned to families using the SITVIT2 international database of the Pasteur Institute of Guadeloupe.

Results: The spoligotyping of the 50 MTB isolates revealed 13 lineages, one being novel. The most frequent shared-types (SIT) identified lineage was the Ural (34%), followed by the Central Asian lineage (10%) and a single isolate (2%) belonging to the rare Manu-Ancestor SIT523 lineage, associated with a highly virulent XDR MTB phenotype. The rest of the SIT isolates (18%) were equally distributed along 9 different lineages. The 13th non-SIT lineage is a novel one constituting 36% of the total isolates.

Conclusion:  The application of Spoligotyping Multiplex Luminex method is a novel, discriminatory and rapid method to use for genotyping of MTB isolates employing the multi-spacer analysis system. Our study showed genomic diversification of MTB isolates from Lebanon.
Epidemiology of pneumococcal infections in hospitalised adult patients in Lebanon with a highlight on non-invasive disease
Authors: Moghnieh Rima , Awad Lyn , Abdallah Dania , Sleiman Rahil , Jisr Tamima , Tamim Hani , Al Helou Mona , Ibrahim Ahmad , Mugharbil Anas , Droubi Nabila , Reslan Lina , Matar Ghassan , Zahran Kamal , Dbaibo Ghassan
Published: February 2018

Introduction: Streptococcus pneumoniae causes a wide range of infections classified as invasive and non-invasive pneumococcal disease (non-IPD).

Methodology: We retrospectively reviewed over a decade the clinical course and outcome of 103 adult subjects infected with S. pneumoniae.

Results: The majority of the subjects (92%) were eligible for pneumococcal vaccination, however none were vaccinated. Most of the infective strains caused non-IPD (64%), with CAP being the leading primary infection (49%). Clinical success was achieved in 71% of the cases and microbiological success in 94% of the cases with available documented follow-up cultures. Yet, 19% of the subjects developed superinfections caused by extensive-drug resistant bacteria with the predominance of ventilator-associated pneumonia (13%). Total in-hospital mortality reached 27% and S. pneumoniae infection attributed mortality was 20%. Using multivariate logistic regression, kidney disease and septic shock were independent risk factors for mortality [Odd’s Ratio (OR) = 14.96 (2.34–95.45), p = 0.004; OR = 5.09 (1.33–19.51), p = 0.02, respectively]. On comparing outcome between subjects with IPD and those with non-IPD, death attributed to S. pneumoniae infection was found to be significantly higher in subjects with IPD (23%, p = 0.023). Nevertheless, clinical success and total in-hospital mortality rates were not statistically different between the two groups (p = 0.056, p = 0.174, respectively).

Conclusion: S. pneumoniae remains a pathogen causing considerable mortality. In adults, non-IPD should be considered of comparable importance as IPD. Increasing pneumococcal vaccine awareness at the healthcare professional and patient levels is essential for increasing vaccine uptake, thus decreasing the incidence, severity and sequelea of pneumococcal disease.
Viral infections of the central nervous system in Qatar: epidemiology, pathogenesis and clinical outcomes
Authors: Ben Abed Fatma , Abukhattab Muhamed , Khalil Obada , Gohar Ahmed , Gazwani Hafedh , Al Masalmani Muna , Al Khal Abdullatif , Butt Adeel A
Published: February 2018

Introduction: Virus-induced diseases of the central nervous system (CNS) represent a significant burden to human health worldwide. They are common causes of morbidities and mortality. There are no previous epidiomologic studies about viral CNS infections done in Qatar or in the Gulf region. We conducted this study to determine the etiology, clinical and epidimiological characteristics, and outcome of viral central nerveous system infection in patients across a larger national healthcare system.

Methodology: We retrospectively evaluated all cerebrospinal fluid findings from January 2011 – March 2015 at any of the 7 hospitals in the Hamad Medical Corporation healthcare system. We included those with an abnormal CSF finding in our study. We excluded those with missing medical records, those with no clinical evidence of CNS infection or proven bacterial CNS infection. Based on pre-defined clinical and CSF (lab, culture, PCR) criteria, persons with abnormal CSF and CNS clinical findings were classified as having meningitis, meningoencephalitis, encephalitis or myelitis. We reviewed the laboratory results to determine the proportion of persons with confirmed viral etiology.

Results: Among 7690 patients with available CSF results, 550 cases met the case definition criteria for viral CNS infection (meningitis 75%; meningoencephalitis 16%; encephalitis 9%; myelitis 0.4%). Two-thirds (65%) were male and 50% were between 16-60 years old. Persons from Southeast Asia (India, Pakistan, Bangladesh, Nepal, and Sri Lanka) accounted for 39.6 of all infections.  A definitive virologic etiologic agent was found in 38%, among whom enterovirus was the most common (44.3%) followed by Epstein-Barr virus (31%) and varicella zoster virus (12.4%). The clinical outcome was overall good, only 2 cases died and the rest discharged to home. Ninety-eight per cent were admitted to medical ward (mean stay 7.8±6.4 days) and 2 % to an intensive care unit. (mean stay 2.7±5.4 days). Among those with confirmed viral etiology, 83.8% received ceftriaxone, 38% received vancomycin and 38% received at least one other antibiotic.

Conclusion: Viral etiology is not uncommon among those evaluated for CNS infection in Qatar, and is most commonly seen in Southeast Asian immigrants. Clinical outcomes are generally excellent in this group of patients. Antibiotics are overly used even when a viral etiology is confirmed. There is a need for clinician education regarding etiology and treatment of CNS infections.
Visceral leishmaniasis in Lebanon a report of four cases: case series and review
Authors: Eldbouni Oussaima , Abihanna Pierre , Beaini Mona , Minari Afaf , Khalife Ibrahim , Gemayel Gladys
Published: February 2018

Introduction: Leishmaniasis comprises a complex of vector-borne diseases, caused by more than 20 species of the protozoan genus Leishmania, and ranging from localized skin ulcers to lethal systemic disease. It is endemic in Asia, Africa, the Americas, and the Mediterranean region. In the Middle East countries like Syria reports high incidence of the disease. In addition to the endemicity of the region for leishmaniasis, the Middle East has seen a great deal of human migration either for earning of livelihood or due to political upheaval in the region. Cutaneous form can be disfiguring but visceral form can be lethal.

Methodology: In this article we report the clinical presentation of 4 cases of visceral leishmaniasis; 3 cases were pediatrics and one immunosuppressed adult patient all of them were from Syria from different regions. The diagnosis was made by bone marrow aspirate; PCR was made for 2 of them and was positive for leishmania infantum. All of them were treated with Amphotericn B lipid formulation (ABELCET) with complete response (definite cure).

Results: We report in this article 4 cases of visceral leishmaniasis treated with amphotericin B lipid complex (Abelcet) following the guidelines with complete remission.

Conclusion: Visceral leishmaniasis is a serious disease and if not treated can lead to death. Lebanon is not known to be endemic for leishmania but since the war the ministry of health reported an outbreak of leishmania and mainly cutaneous leishmania. Here we present 4 cases of visceral leishmania and a review of the latest guidelines on the treatment modalities and protocols.
« Laissons de côté les questions de sentimentalité »
Authors: Depecker Thomas
Published: February 2018

L’imbrication des recherches sur la nutrition animale et de la réforme des techniques de quantification dans les exploitations agricoles entraîne au xix e siècle la transformation des préoccupations agronomiques concernant le rationnement du bétail et l’équivalence des matières alimentaires. Hormis les débats savants, ce sont d’abord chez les maîtres de poste au cours du second tiers du siècle que ces considérations sont mises en œuvre, puis dans deux grandes écuries issues de fusions des compagnies parisiennes de transport en 1855, la Compagnie générale des omnibus (CGO) et la Compagnie générale des voitures de place et de remise (CGV). Le passage d’acteurs « isolés » et pas totalement organisés sur le mode de l’entreprise capitaliste à de grandes compagnies possédant les ressources économiques et intellectuelles pour mener ou faire mener en grand des expérimentations, et intégrer au sein de leurs problématiques économiques l’évolution des techniques de mesure physico-chimique, est tout à fait crucial dans l’analyse de la genèse et du développement de « l’alimentation rationnelle ». La réduction des coûts de la ration reste toujours un sujet sensible, mais à la différence de leurs prédécesseurs la CGO et la CGV font usage de l’expertise scientifique pour assurer au public et aux actionnaires le caractère quantifié et contrôlé des expériences, et montrer à un public de plus en plus large que processus physiologiques et optimisation économique ne sont pas étrangers l’un à l’autre.
Structure and Surface Properties of Al3+- Modified Sepiolite
Authors: Liu Wen Bo , Jin Sheng Ming , Cui Kui Xin , Zhan Xue Hui
Published: February 2018

Al3+-modified sepiolite was synthesized through hydrothermal treatment of acidified sepiolite using sodium aluminate as a modifier. The structure and surface properties of the modified sepiolite were characterized by XRD, FTIR, NMR, and Zeta potentials. The XRD and FTIR results demonstrated that Al3+ions were introduced into the sepiolite lattice.29SiNMR of the sepiolite ore showed that Si atoms had three configurations with chemical shifts of -98.4, -95.2, and -92.5 ppm with the atomic ratio of 1.39: 1.43: 1, which was assigned to the center silicon, edge silicon, and near-edged silicon atoms, respectively. For the as-prepared Al3+-modified sepiolite, the signal intensity of the edge silicon atoms decreased and shifted from -95.2 ppm to -94.5 ppm. Moreover, a new chemical shift of - 87.4ppm belonging to Q1structure appeared. The ratio of four configurations of silicon atoms was 1.43: 1: 1.53: 1.04.27AlNMR of Al3+-modified sepiolite showed that Al atoms have two configurations corresponding to the tetra-coordination and octahedral coordination, respectively. The results of NMR revealed that the sepiolite was modified by substitution of Si atoms in the framework and Mg atoms in the interlayer, resulting in a less negative charge on the surface of Al3+-modified sepiolite.
Investigation on Rheological Characteristics of Fresh Cement Mortar
Authors: Cao Zhi Long , Xue Li Hui , Tian Sha Sha , Yu Jian Ying , Zhang Huang
Published: February 2018

The rheological properties of cement-based materials can be used to guide its construction. In this paper, rheological characteristics of fresh cement mortar (FCM) were investigated. The rheological model and its parameters of the FCM under different hydration time, different water to cement ratio (w/c) and sand to cement ratio (s/c) were obtained by the rheological testing and model analyzer. The result indicated that rheological model of the FCM is transformed from Burgers model to Bingham model with the extension of hydration time. And the model transformed from Burgers model to five component model with the decrease of w/c and the increase of s/c. However, the superplasticizer has little effect on the rheological model of cement mortar. The plastic deformation of the fresh cement mortar increased gradually with the prolongation of the hydration time, and the plastic yield value increased gradually from 50Pa to 250Pa with the increase of s/c. The change rate of plasticity of mortar is reduced from 422Pa/h to 107Pa/h with the increase of superplasticizer’s dosage, which shows the addition of superplasticizer retards the hydration rate.
Effects of Process Parameters on Morphologies and Microstructures of Laser Melting Deposited V-5Cr-5Ti Alloys
Authors: Bai Lin Rui , Le Guo Min , Li Jin Feng , Liu Xue , Li Xiu Yan
Published: February 2018

V-Cr-Ti alloys are promising structural materials for future nuclear systems. In this study, a laser melting deposition process has been applied to the fabrications of V-5Cr-5Ti alloys. Laser powers of 1200W, 1400W and 1600W, scanning speeds of 400 mm/min and 600 mm/min, and scanning strategies of single directional scanning and dual directional scanning have been applied to investigate the effects on the morphologies and microstructures of formed individual deposits and thin walls. The dual directional scanning is favored for fabricating thin walls with regular shape, comparing to the single directional scanning. Microstructures of the deposits and walls consist of columnar grains and equiaxed grains. Due to the effects on temperature gradients, both the laser powers and deposition duration show significant effects on the microstructural evolutions of the thin wall samples. As the laser power and deposition duration increase, columnar to equiaxed transitions have been observed. The regions containing columnar grains and equiaxed grains have a <100> fiber texture and a random texture, respectively.
Fatigue Mechanism of Domestic 316LN Stainless Steel in Simulated AP1000 First-Loop Water Environment
Authors: Zhong Wei Hua , Tong Zhen Feng , Wang Zheng , Li Jin Xu , Yang Wen
Published: February 2018

Fatigue fracture surfaces and crack morphologies of 316LN stainless steel that test in a simulated AP1000 first-loop water and air environment were investigated by SEM, LSCM and EBSD. The results showed that, the fatigue crack initiated at persistent slip band, impurities and grain boundary, and then propagated in a trans-granular manner with typical fatigue striations. Characteristics of corrosion fatigue, such as brittle fatigue striation, rhomboid corrosion product and the trace of corrosions were found on the fracture surface of first-loop water environment specimen. The strain on first-loop water environment specimen is unevenly distributed surrounding the crack, and the gradient is not obvious, while that on air environment ones is evenly distributed , and the distribution gradient is associated with the distance of crack from . The fatigue crack propagation was accelerated in the first-loop water environment, and the EAC mechanism is most likely to be HIC.
Effect of Slab Centerline Segregation on DWTT Properties of 22mm Thick X80M Hot Rolled Steel Strip
Authors: Wang Hao , Bao Yan Ping , Wang Min , An Hang Hang , Su Cheng
Published: February 2018

The replacement of 22mm thick X80M hot rolled strip for the traditional heavy plate production technology has remarkable advantages in improving the yield, reducing the cost of manufacturing and improving the outer diameter adjustment of pipeline. Low temperature anti Drop Weight Tear Test (for short DWTT) performs one of the key research problems of 2250mm hot rolling line production of this specification. Aiming at the problem of the substandard performance of rolled DWTT development process, the slab fracture morphology of different proportion and slab thickness direction component segregation degree of system were analyzed through the electron microscope. The results showed that the thickness of steel strip was serious segregation and is the main factor affecting the performance of DWTT. By optimizing the caster arc alignment and secondary cooling water, then improving the central segregation effect, the performance of DWTT can be effectively improved, and a stable development and production of 22mm thickness X80M pipeline steel hot rolledstrip can be achieved.
Effect of Ultra-Fast Cooling Rate on the Microstructure and Mechanical Properties of High Strength Cold-Rolled Sheet under Continuous Annealing
Authors: Zhang Kai , Song Ren Bo , Gao Feng , Niu Wen Jie , Chen Chi
Published: February 2018

The effect of different fast cooling rates on the microstructure and mechanical properties of the V and Ti microalloyed high strength cold-rolled sheet was studied under laboratory conditions. Five different fast cooling rates were set up as 20°C/s, 50°C/s, 200°C/s, 500°C/s and 1000°C/s, respectively. Optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the microstructure, and the mechanical properties were also tested. The results showed that with the increase of fast cooling rate from 20°C/s to 1000°C/s, the grains of martensite and ferrite were finer, and the average grain size of both martensite and ferrite decreased from 7.7μm to 3.9μm. The proportion of ferrite in the two phases decreased while that of the martensite increased from 25.7% to 62.1%. The morphology of martensite tended to be lath, and the density of dislocation in the ferrite grains nearby the martensite gradually increased. With cooling rate rising from 20°C/s to 1000°C/s, the yield strength of the experimental steel increased from 381MPa to 1074MPa, and the tensile strength increased from 887MPa to 1199MPa. And the elongation decreased from 14.2% to 7.2%, and the product of strength and elongation decreased from 12.6GPa·% to 8.6GPa·%.
Simulation Study on Heating Process of Hot Rolled Steel Strip for X80M Pipeline Steel
Authors: Wang Jian Gang , Wang Hao , Bao Yan Ping , Wang Min , Jing Guo
Published: February 2018

The simulation experiments of heating process for X80 pipeline steel were carried out to investigate the influence of austenite grain size and micro alloy element solution. The results showed that a reasonable industrial production process of slab heating control system was developed, and the guidance of good industrial test could be provided for the acquisition of reasonable microstructure of 22mm thickness X80 pipeline steel hot rolled steel strip.
Interfacial Microstructure and Formation Mechanism of Zirconia Ceramic and Nb Brazed with Ag-Cu-Ti Powder without and with Mo-Particle-Reinforced
Authors: Wang Na , Wang D.P. , Yang Zhen Wen , Wang Ying
Published: February 2018

Zirconia (ZrO2) ceramic and Nb were brazed using Ag-Cu-Ti powder without and with Mo-particle-reinforced. The effects of the brazing temperature, holding time and Mo content of the composite filler on the interfacial microstructures and joining mechanism of ZrO2/Nb brazed joints were investigated. By increasing the brazing temperature and holding time, the thickness of Ti3Cu3O layer increased and the thickness of TiO layer decreased, while the total thickness of the reaction layers increased slightly with the sufficient interfacial reaction. Meanwhile, the blocky Ti-Cu compounds gradually accumulate and grow up in the brazing seam. The calculated Ti activity increased first and then decreased as the Mo content was increased from 5 to 40 wt%. When the Mo content was 5wt%, only single Ti3Cu3O reaction layers formed adjacent to the ceramic substrate. By increasing of Mo particles, TiO layer became thicker. When 40 wt% Mo particles were added to the composite filler, Mo particles aggregated into larger clumps damaged the shear strength of brazing joint.
Tensile Properties of Carbon Nanoring Linked Graphene Sheets: A Molecular Dynamics Investigation
Authors: Shi Gang , He Yong Lyu , Zhang Jian Wei , Jiang Da Zhi
Published: February 2018

The effects of CNR diameter and CNR number on tensile properties of the CNR-graphene hybrid structure (CGHS) were studied by molecular dynamics simulation in this paper. Results show that interactions between adjacent graphene sheets are significantly strengthened by the cross-linked CNRs. For CGHSs, the maximum strength is ~64.0 GPa and the maximum Young’s modulus strength is ~763 GPa. When the diameter of CNRs is large or the CNR linkers are dense, the tensile strength of CGHSs reached the maximum and the fracture mechanism of CGHSs changed from CNR-graphene junction fracture to graphene sheet fracture. Present work should serve as guide to experiments concerning physical properties of this novel material.
Design of New Weathering Steels through Thermodynamic Model of Nitrogen Solubility and CALPHAD
Authors: Cheng Jian , Guo Yue Hua , Liu Ming , Shen Hou Fa
Published: February 2018

In this paper, a new vanadium nitrogen (V-N) microalloyed high strength weathering steel with the yield strength and tensile strength higher than 550 MPa and 650 MPa was designed and developed by using thermodynamic model of nitrogen solubility and phase diagram database of CALPHAD. Based on the established thermodynamic model, the effect of C content on nitrogen solubility in molten steel was investigated. The nitrogen solubility increases with the decrease of C content and the increase of temperature. In order to obtain higher N content in steel, C content must be controlled at a low range of 0.03~0.04%. Furthermore, an allowable concentration range of C and N was selected based on the phases quantity prediction of VN/V(C,N), (Cr, Fe)7C3, AlN and γ through the CALPHAD approach. Consequently, five new weathering steels were designed with variations of (C+N) content or N/C ratio. And then the four selected steels were cast, hot rolled and air cooled. The tensile tests at the room temperature show that the yield strength and tensile strength of steel with 0.032% C and 0.038%N satisfy the requirements of new generational weathering steel.