bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on the Densification Process of the Mechanically-Alloyed Amorphous 2Si-B-3C-N Powder
Authors: Zhang Peng Fei , Jia De Chang , Yang Bin , Wang Guang Xin
Published: August 2018

A mixture of the commercially available cubic silicon powder, hexagonal boron nitride powder and graphite powder was mechanically alloyed to prepare amorphous 2Si-B-3C-N composite powder. The amorphous powder was heated up to 1900°C in nitrogen, with a heating rate of 20°C/min and under a pressure of 80 MPa. Careful investigation was carried out on the densification curve, the microstructure and the mechanical properties of the prepared ceramics. Results show that the amorphous 2Si-B-3C-N powder mainly consists of near-spherical agglomerates, with an average size of 3.5±2.4 micrometers. When the amorphous powder was hot pressed, the densification process mainly included three stages, the denser packing of powder particles with the help of axial pressure, the initial sintering at about 1500-1800°C, and the rapid sintering at temperatures approximately higher than 1830°C. When the 2Si-B-3C-N ceramic was hot pressed at 1900°C for 10-30 mins, it exhibited large volume shrinkage, noticeable reduction of pores, and significantly improvement of density and mechanical properties. The applied high temperature and large pressure may give rise to severe plastic deformation, viscous flow and creep of powder particles, which greatly contribute to the rapid densification of the amorphous 2Si-B-3C-N powder.
Thermal Expansion of SrZr4-xTix(PO4)6 Ceramics
Authors: Wang Yang , Song Yuan Yuan , Zhou Yuan Yuan , Yang Lu Ping , Liu Fu Tian
Published: August 2018

Low thermal expansion ceramics have been widely applied in multiple fields. In this paper, a series of low thermal expansion ceramics SrZr4-xTix(PO4)6 was prepared and characterized. The SrZr4-xTix(PO4)6 ceramics could be well sintered in the temperature range of 1400~1500 °C. The effect of the addition of Ti substituting Zr and the sintering temperature was studied. The Ceramic with x =0.1 sintered at 1450 °C, the SrZr4-xTix(PO4)6 had a high relative density. The thermal expansion coefficients were about 3.301×10-6 °C-1. It was demonstrated that the microstructure of the SrZr4-xTix(PO4)6 could be altered by adding varying amount of Ti to tailor the thermophysical properties of the material.
The Mechanical Properties and Thermal Resistance of Fly Ash Geopolymer Foams
Authors: Ng Hui Teng , Heah Cheng Yong , Liew Yun Ming , Abdullah Mohd Mustafa Al Bakri , Hussin Kamarudin
Published: August 2018

In the present work, a comparative study of the thermal performance of unfoamed and foamed geopolymers was investigated. The geopolymers were prepared by mixing fly ash with alkali activator (a mixture of sodium hydroxide and sodium silicate). The geopolymer foams were prepared by adding hydrogen peroxide (H2O2, 2wt.% and 4wt.%). The geopolymers were cured at room temperature (29°C) for 24 hours and at 60°C for another 24 hours. The bulk density and compressive strength decreased with increasing H2O2 up to 2wt.% and increased when 4wt.% of H2O2 was added. In order to test the thermal resistance, the geopolymers were heated at elevated temperature (200- 1000°C). Unheated geopolymers showed bulk density and compressive strength in the range of 1.6– 1.7g/cm3 and 15–17MPa, respectively. When heated up to 1000°C, the geopolymers could withstand high temperature without any disintegration and spalling. Both unfoamed and foamed geopolymers showed highest compressive strength at 200°C (17–22MPa). Further decreased in compressive strength was observed upon heating up to 800°C (10–17MPa). The compressive strength regained (14–21MPa) when heated up to 1000°C. The compressive strength was even higher than that recorded at room temperature. In the present work, unfoamed geopolymers showed overall higher thermal resistance than foamed geopolymers.
Preparation and Characterization of 3Y-ZrO2 Composite Ceramics
Authors: Ju Yin Yan , Gan Xue Xian , Song Jie Guang , Wang Fang , Huang Qun , Xiong Chao
Published: August 2018

Dense 3Y-ZrO2composite ceramics were prepared by using 3Y-ZrO2nanopowders as the raw materials, via the process of ball milling, granulating, molding and calcination.We investigated the microstructure, surface morphologies, the mechanical property, the density and linear shrinkage rate of the sintered ceramics and the effect of the ball milling technics and the sintering technics on the above properties of the3Y-ZrO2composite ceramics via SEM and testing. The results show that the most excellent technics in all was explored as follows: the ultrafine ball milling by adding zirconium balls of 2 mm at the speed of 35 r/min for 10 h, with the mass ratio of zirconium ball, water and mixed powders of 6:1:1, the granulaing with 1.5% PVA, the CIP, the pre-sintering to remove the organic substrate to 500°C and the microwave sintering from 20°C to 1450 °Cin 80 min in which the duration at 1450°C was 20 min and the natural cooling time of the samples was 90 min. And the 3Y-ZrO2composite ceramics obtained by this process have a relative density of 99.2%, bending strength of 1098 MPa, and a fracture toughness of 7.8 MPa·m1/2.
Fabrication of Dense Silica Ceramics through a Stereo Lithography-Based Additive Manufacturing
Authors: Wang Ying Ying , Li Ling , Wang Zai Yi , Liu Fu Tian , Zhao Jia Hui , Zhang Ping Ping , Lu Chun
Published: August 2018

Silica ceramics were fabricated via an additive manufacturing process based on stereolithography. Ceramic suspension with low viscosity and high solid loading is of importance to stereolithography based UV-curable. In this work, to meet the requirements of stereolithography, effects of temperature, additive content and ball-milling time on the viscosity of silica slurry were investigated, and properties of silica ceramics sintered at different temperature were also researched.The results show that increasing temperatures strongly decrease the viscosity unless when the temperature is above 70°C. The minimum of viscosity was observed for an appropriate addition of dispersant, which is corresponding to the best dispersion state of silica particles in the photopolymerizable monomer. And optimizing ball-milling time showed the lowest viscosity suitable for the stereolithography process. The appropriate temperature, additive content and ball-milling time facilitating stereolithography was 70°C, 2% and 60min respectively. The prepared ceramics sintered at 1220°C showed a density and flexural strength of 1.57g/cm3 and 13.31MPa respectively.
The Impedance Spectroscopy Study of the Oxides Layer in Thermal Barrier Coatings
Authors: Wang Zi Yuan , Wang Min , Yuan Ya Jie , Pan Wei
Published: August 2018

Air-plasma-sprayed (APS) thermal barrier coatings (TBCs) were oxidized in air at different temperatures for 1000h and sequentially investigated by impedance spectroscopy (IS) and scanning electron microscopy (SEM). After oxidation at temperatures higher than 900°C, a thermally grown oxide (TGO) layer was formed at the bond coat/topcoat interface in TBCs. The impedance spectra of oxidized TBCs typically contains two relaxation processes that stem from the yttria-stabilized zirconia (YSZ) topcoat of TBCs and the TGO layer. The TGO resistivity that obtained by simulating the impedance spectra increased with the increasing of annealing temperature, demonstrating the growth and the densification of TGO layer.
Preparation and Characterization of Na2O-Y2O3-P2O5-SiO2 Transparent Glass Ceramics
Authors: Zhao Meng Jie , Zou Xiang Yu , Wei Qin Lei , Meng Shuo , Zhang Hong Bo , Su Chun Hui
Published: August 2018

Transparent glass ceramics containing Na3.6Y1.8(PO4)3 crystals were successfully synthesized using high temperature melting quenching and subsequent heat treatment of the precursor glass with a composition 15Na2CO3-3Y2O3-45SiO2-31H3BO3- 5.4P2O5-0.6Sb2O3 (mol%). The impact of heat treatment is investigated in detail. The glass sample was tested by differential scanning calorimetry analysis to determine the heat treatment system. The ideal heat-treated condition is at 650°C for 2 h. The structure and morphology properties were systematically analyzed by recording X-ray diffraction patterns and scanning electron microscopy images, which indicate that Na3.6Y1.8(PO4)3 crystal were precipitated homogeneously among the glass matrix. The microstructural of precursor glass and glass ceramic were compared by analyzing FTIR spectra, indicating the formation of phosphate groups in glass ceramic. The refractive index of glass ceramics samples were measured. In the visible region, the transmittance of glass ceramics is up to 85%. Moreover, the relationship between the refractive index of the sample and the transmittance is discussed.
Fabrication of YSZ/SNDC Bilayer Electrolytes by Spark Plasma Sintering
Authors: Li Tian Jun , Zhang Meng Fei , Yuan Ya Jie , Zhao Xiao Hui , Pan Wei
Published: August 2018

Doped ceria has been reported as a promising candidate of electrolyte applicable for solid oxide fuel cells (SOFCs) and oxygen sensors due to its high ionic conductivity at intermediate temperature. However, it suffers from certain limitations including the existence of electronic conductivity at reduced atmosphere, which would thus increase the leakage current in cells, and the low fracture strength. In this work, we fabricated a bilayer electrolyte with samarium and neodymium co-doped ceria (SNDC) and yttrium stabilized zirconia (YSZ) using spark plasma sintering (SPS) method, which possess the advantages of two layers, high conductivity of SNDC and good electron blocking ability of YSZ. Both layers of the specimen we obtained were dense and well crystallized according to the scanning electron microscope (SEM) and X-ray diffraction (XRD). The bilayer electrolyte exhibits improved ionic conductivity than YSZ with the value of 1.7 S/cm at 550.
Preparation and Property of LSGM-Carbonate Composite Electrolyte for Low Temperature Solid Oxide Fuel Cell
Authors: Lin Xu Ping , Zhong Hai Tao , Chen Xing , Ge Ben , Ai De Sheng
Published: August 2018

The LSGM-carbonate composite electrolyte is a new type of medium and low temperature SOFC electrolyte material, which has great application potential. In this paper, the molten salt infiltration method was used to prepare the LSGM-carbonate composite electrolyte. The results of SEM test proved that the molten salt infiltration method was more appropriate in preparing the LSGM-carbonate composite electrolyte comparing with direct mixing method. The influence of the type and content of pore forming agent was investigated. The result showed that the polymethyl methacrylate (PMMA) had an excellent pore forming performance and could create interconnected pore structures successfully in LSGM matrix. The XRD result indicated that the LSGM-carbonate composite electrolyte showed almost a single LSGM phase and the carbonate remained glass state. Four terminal method was used to measure the conductivity. The result showed that the conductivity of the LSGM-carbonate composite electrolytes was increased by one order of magnitude compared with pure LSGM. The conductivity of LSGM-carbonate composite electrolytes increased firstly and then decreased with the increasing of PMMA. The LSGM-carbonate composite electrolyte prepared by 25 wt.% PMMA addition has the highest conductivity during the whole range of test temperature and reached 0.3 S.cm-1 at 600°C.
The Microstructure and Growth Behavior of Bi2Fe4O9 Superfine Particles Synthesized by Hydrothermal Method
Authors: Song Hai Peng , Sun Qi , Wang Yuan Yu
Published: August 2018

In this work, Bi2Fe4O9superfine particles were prepared by hydrothermal method and effects of hydrothermal conditions on the microstructure of Bi2Fe4O9, especially the concentration of OH-([OH-]) in initial solutions, were investigated. The results showed that [OH-] had obvious influences on the growth of Bi2Fe4O9under the same hydrothermal temperature and hydrothermal time. Phase structure of Bi2Fe4O9unchanged with the increase of [OH-] and maintained orthorhombic structure. Besides, the microstructure of Bi2Fe4O9was carefully studied through transmission electron microscopy (TEM). The results suggested that the mechanism of Bi2Fe4O9growth was Ostwald ripening. In conclusion, Bi2Fe4O9superfine particles with good morphology and microstructure can be successfully synthesized when the concentration of OH-is 2 mol/L and hydrothermal conditions are 240 °C for 6h.Keywords: Bi2Fe4O9, hydrothermal method, phase structure, growth mechanism Topic code numbers: C2
Effects of Prilling Process on the Microstructures and Electrical Properties of Lanthanum Chromite Ceramics
Authors: Yin Xing Lian , Zhao Qing , He Dong Lin , Chang Ai Min
Published: August 2018

Lanthanum chromite(LaCrO3) with different amounts of PVB solution were synthesized by classical solid state reaction. We have studied the effects of different amounts of PVB solution( 0 mL, 1 mL, 2 mL, 3 mL) during prilling process on the microstructures and electrical properties of LaCrO3. The scanning electron microscopes, relative densities and resistivities of samples suggest: (1) the sinterability of LaCrO3is optimal among samples when adding 1 mL PVB solution to LaCrO3powder during prilling process. (2) sample with 1 mL PVB solution has the highest resistivity, while other counterparts’ resistivities have no distinct correspondence with the amount of PVB solution.
Preparation and Performance of Zirconia Fiber Board
Authors: Tao Liu Shi , Chen Yu Feng , Zhang Shi Chao , Deng Ke Wei , Sun Hao Ran , Sun Xian Kai , Yan Da Chen , Fang Kai , Li Na
Published: August 2018

Zirconia fiber not only can be used for a long time in 1600°C, but also has low thermal conductivity at high temperature. Due to the excellent insulation performance, it has a broad application prospect in aerospace, aviation, energy and other areas. In the present study, we chose yttrium stabilized zirconia fibers and nanometer zirconia powder as main material and adding soluble starch, zirconium sol as low temperature and high temperature binder. Rigid zirconia fiber board was prepared by material slurry, filter shaping, stripping drying and high temperature calcination. After high temperature calcination of 1600°C for 12h, sample pore are mainly concentrated in 25-75μm, bending strength performance is best when the adding amount of nanometer zirconia powder was 7%, the thermal conductivity is only 0.132 W·m-1·K-1 at 1400°C.
Computer Modeling of Ceramics Sintering: Effects of Inhomogeneity on Sintering Kinetics
Authors: Luo Wen Dong , Qiu Hai Peng , Pan Jing Zhe
Published: August 2018

In the sintering of ceramics, cracks are inevitably encountered after sintering. But very few studies have been presented in the literature for qualifying and quantifying effects of inhomogeneity on sintering kinetics. Therefore, a series of detailed sintering variables such as grain size, surface tension and diffusivity are chosen to study the effects of their inhomogeneity on sintering kinetics through a computational model calculated by computer.Furthermore, there are two main achievements in this computational model that first one is providing a numerical solution for the curvature at triple junction (pore tip) of microscopic particles, and second one is considering the effect of surface diffusion on first-stage sintering where diffusion mechanism is coupled by grain-boundary and surface diffusion.
Mechanism and Technics to Produce Geographical Indication Products of Chinese Blue-and-White Porcelain
Authors: Shao Gang Qin , Zhong Xiao Bin , Zhang Yong , Feng Xin Yi , Zhu Can , Mao Jia Wei , Qiu Zhao Biao , Xie Gui Zhen , Li Hong Bin , Zhong Zhen Chang , Zhong You Yan
Published: August 2018

For over 1400 years, Dapu county, under the jurisdiction of Meizhou city, Guangdong province, one cradleland of the Hakka traditional culture, is renowned for the blue and white porcelain in China. In this work, the mechanism and technics to produce Dapu geographical indication products of blue-and-white porcelains with high quality were studied, based on the distinct characteristics of local resources.
Effect of B4C and SiO2 on Bond Property for Phenolic Resin-Based Adhesive
Authors: Zhang Feng , Hu Chuan Qi , Zhang Shi Chao , Sun Hao Ran , Tian Yuan , Sun Xian Kai , Fang Kai , Yan Da Chen , Chen Yu Feng
Published: August 2018

In this paper, the modified phenolic resin-based adhesive was prepared by dissolving different components. After low temperature curing, SiC samples were bonded by the binder. The samples were treated at different temperatures (400°C, 800°C, 1200°C, 1500°C) under an inert atmosphere. The bonding strength of samples was tested after heat treatment at room temperature. The results showed that the bonding strength of the B4C modified phenolic resin (PF) based adhesive is the highest. When the heat treatment temperature was above 1200°C, the bond strength increased with the additive amount of boron carbide at room temperature. The microstructures of the samples were observed by optical microscope and scanning electron microscope. The effects of the modified filler and heat treatment temperature on the bonding strength of the phenolic resin based adhesive were investigated. The bonding strength of boron carbide-modified phenolic resin-based binder was tested under high temperature. It was found that the bond strength at high temperature was lower than that at room temperature, and the bond strength decreased with the increase of temperature.
Customized Chemical Compositions Adaptable for Cleaning Virtually all Post-Etch Residues
Authors: Cazes M. , Pizzetti Christian , Daviot Jerome , Garnier Philippe , Broussous Lucile , Gabette Laurence , Besson Pascal
Published: August 2018

A post-etch residue cleaning formulation, based on balancing the aggressiveness of hydrofluoric acid with its well-known residue removal properties is introduced. In a series of investigations originally motivated by the cleaning challenge provided by high-k dielectric-based residues, a formulation platform is developed that successfully cleans residues resulting from the plasma patterning of tantalum oxide and similar materials while maintaining metal and dielectric compatibility. It is further shown that the fundamental advantages of this solution can be extended to the cleaning of other, more traditional post-etch residues, with no sacrifice in compatibility, as demonstrated by measurements on blanket films and through SEM data.
Surface Recombination Velocity Imaging of HF-Etched Si Wafers Using Dynamic Heterodyne Lock-In Carrierography
Authors: Sun Qi Ming , Melnikov Alexander , Mandelis Andreas , Pagliaro Robert
Published: August 2018

Surface electronic quality of wet-cleaned Si wafers was characterized quantitatively and all-optically via spatially-resolved surface recombination velocity (SRV) imaging using InGaAs-camera-based dynamic heterodyne lock-in carrierography. Six samples undergone four different hydrofluoric special-solution etching conditions were tested, their SRV distributions at different queue times after the hydrogen passivation processes were obtained, and a quantitative assessment of their surface electronic quality was made based on the evolution behavior of globally-integrated information from the SRV images. The data acquisition time for an SRV image with full camera pixel resolution was about 3 min. The methodology introduced here is promising for in-line nondestructive testing/evaluation and quality control at different fabrication/manufacturing stages in the electronic industry. Keywords: heterodyne lock-in carrierography, surface recombination velocity, quantitative imaging, HF etching, Si wafers
Industry Context for Semiconductor Wet Etch and Surface Preparation
Authors: Gale Glenn W.
Published: August 2018

The semiconductor industry is undergoing a transition driven by end use markets. In recent years, mobile devices have been the leading generator of growth. Now the connection of various products and machines to the internet is generating new and extensive demands for memory (storage of the data), logic (intelligent processing of the data including machine learning), and sensing (e.g., image sensors generating visual data). Thus the versatile planar MOS transistor based semiconductor technology has diverged into various specialized and complex branches, with each technology type using unique approaches to address scaling challenges. These lead to specific requirements for semiconductor wafer surface preparation. This paper will review the high level industry trends and how they affect surface preparation specifically.
Toward the Surface Preparation of InGaAs for the Future CMOS Integration
Authors: Lim Sang Woo
Published: August 2018

The integration of III-V and Ge materials on Si surface causes many issues with complexity such as lattice mismatch with silicon. In particular, the surface preparation and passivation of InGaAs is very challenging, because the formation of InGaAs/high-K interface is important, but not well understood. For the systematical study of InGaAs surface during wet processes, the effect of various wet etching processes on the surfaces of binary III-V compound semiconductors (GaAs, InAs, GaSb and InSb) was studied from the viewpoints of surface oxidation, material loss (dissolution), and passivation. Based on that, further effort to understand the surface reactions on ternary InGaAs compound semiconductor was made. In addition, process sequential effect on the InGaAs surface was investigated.
Neutrophils Promote Amphiregulin Production in Intestinal Epithelial Cells through TGF-β and Contribute to Intestinal Homeostasis
Authors: Chen Feidi , Yang Wenjing , Huang Xiangsheng , Cao Anthony T. , Bilotta Anthony J. , Xiao Yi , Sun Mingming , Chen Liang , Ma Chunyan , Liu Xiuping , Liu Chang-Gong , Yao Suxia , Dann Sara M. , Liu Zhanju , Cong Yingzi
Published: August 2018

Neutrophils are the first responders to sites of inflammation when the intestinal epithelial barrier is breached and the gut microbiota invade. Despite current efforts in understanding the role of neutrophils in intestinal homeostasis, the complex interactions between neutrophils and intestinal epithelial cells (IECs) is still not well characterized. In this study, we demonstrated that neutrophils enhanced production of amphiregulin (AREG), a member of the EGFR ligand family, by IECs, which promoted IEC barrier function and tissue repair. Depletion of neutrophils resulted in more severe colitis in mice because of decreased AREG production by IECs upon dextran sodium sulfate (DSS) insult. Administration of AREG restored epithelial barrier function and ameliorated colitis. Furthermore, neutrophil-derived TGF-β promoted AREG production by IECs. Mechanistically, TGF-β activated MEK1/2 signaling, and inhibition of MEK1/2 abrogated TGF-β–induced AREG production by IECs. Collectively, these findings reveal that neutrophils play an important role in the maintenance of IEC barrier function and homeostasis.
INVASIVE ASPERGILLOSIS IN CHILDREN: UPDATE ON CURRENT GUIDELINES
Authors: Apsemidou Athanasia , Petridis Nikolaos , Vyzantiadis Timoleon-Achilleas , Tragiannidis Athanasios
Published: August 2018

Invasive aspergillosis (IA) is an important cause of infectious morbidity and mortality in immunocompromised paediatric patients. Despite improvements in diagnosis, prevention and treatment, IA is still associated with high mortality rates. To address this issue, several international societies and organisations have proposed guidelines for the management of IA in the paediatric population. In this article, we review current recommendations of the Infectious Diseases Society of America, the European Conference on Infection in Leukaemia and the European Society of Clinical Microbiology and Infectious Diseases for the management and prevention of IA in children.
EPIDEMIOLOGY OF MALARIA IN THE STATE OF QATAR, 2008-2015
Authors: Farag Elmoubasher , Bansal Devendra , Chehab Mohamad Abdul Halim , Al-Dahshan Ayman , Bala Mohamed , Ganesan Nandakumar , Al Abdulla Yosuf Abdulla , Al Thani Mohammed , Sultan Ali H. , Al-Romaihi Hamad
Published: August 2018

Background and ObjectivesImported malaria poses a serious public health problem in Qatar because its population is “naïve” to such infection; where local transmission might lead to serious life-threatening infection and might even trigger epidemics.MethodsThis study is a retrospective review of the imported malaria cases in Qatar reported by the malaria surveillance program at the Ministry of Public Health (MoPH), during the period between January 2008 and December 2015. All cases were imported and underwent parasitological confirmation through microscopy.ResultsA total of 4092 malaria cases were reported during 2008-2015 in Qatar. The demographic features of the imported cases show that the majority of cases were males (93%), non-Qatari(99.6%), and aged 15 to 44 years(82.1%). Moreover, P. vivax was found to be the main etiologic agent accounting for more than three-quarters (78.7%) of the imported cases. In addition, almost a third (33.1%) of the cases were reported during the months of July, August, and September.ConclusionsImported malaria in Qatar has witnessed an increase during the past 7 years, despite a long period of constant reduction; where the people most affected were adult male migrants from endemic countries. Many challenges need to be overcome to prevent the reintroduction of malaria into the country.
OUTBREAK OF BURKHOLDERIA CEPACIA INFECTION: A SYSTEMATIC STUDY IN A HEMATOLOGY-ONCOLOGY UNIT OF A TERTIARY CARE HOSPITAL FROM EASTERN INDIA.
Authors: Baul Shuvra Neel , De Rajib , MANDAL PRAKAS KUMAR , Roy Swagnik , Dolai Tuphan Kanti , Chakrabarti Prantar
Published: August 2018

Background: Burkholderia cepacia, an aerobic gram-negative bacillus, is a frequent colonizer of fluids used in the hospital ward. It poses little risk of infection to healthy people; however it is a known important opportunistic pathogen causing morbidity and mortality due to its intrinsic resistance to most of the antibiotics in hospitalized patients. Small hospital outbreaks are frequent. B. cepacia may occur as an opportunistic infection in hemato-oncology patients.  Here we present an outbreak of  Burkholderia cepacia infection in hematology ward of our institute.Methods: Febrile episodes as defined by IDSA guideline, 2010 were followed, and blood for culture and sensitivity was sent in all the events. The culture was done by an automated method using Bactalert 3d  Biomeriux  & sensitivity pattern by Microscan Siemens method and subsequently detected by  PCR based method.Results: During   September 2016 to February 2017 (six months), a total of 498 blood cultures were sent during febrile episodes. Out of which 60 (12%) came out to be positive for different microorganisms. Out of all positive cultures, Burkholderia cepacia was detected in 29 (48%)  patients, which reduced drastically following the change in antibiotic administration practice.  All isolates showed sensitivity to pipercillin+tazobactum, cefoperazone+sulbactum, fluoroquinolones, cotrimoxazole and carbapenems and resistance to polymyxin B and colistin. With timely intervention by appropriate intravenous antibiotics as per culture sensitivity result and change in antibiotic preparation practice, overall mortality was low 1 (4%) out of 29 culture positive episodes.
THE EMERGING RESISTANCE IN NOSOCOMIAL URINARY TRACT INFECTIONS: FROM THE PEDIATRICS PERSPECTIVE.
Authors: Devrim Fatma , Serdaroğlu Erkin , Çağlar İlknur , Oruç Yeliz , Demiray Nevbahar , Bayram Nuri , Ağın Hasan , Çalkavur Şebnem , Sorguç Yelda , Dinçel Nida , Ayhan Yüce , Yılmaz Ebru , Devrim İlker
Published: August 2018

Background: Healthcare–associated infections results increased healthcare costs and mortality. There are limited studies concerning the distribution of the etiologic agents and the resistance patterns of the microorganisms causing healthcare–associated urinary tract infections (HA-UTI) in pediatric settings.Objectives: The aim of this study was to evaluate the distribution and antibiotic susceptibility patterns of pathogens causing HA-UTI in children.Material and Methods: Isolates from 138 children with UTI who were hospitalized in pediatric, neonatal and pediatric surgery intensive care units were reviewed.Results: Most common isolated organism was Kleibsella pneumoniae (34.1%) and Escherichia coli (26.8%). Among the Pseudomonas aeruginosa, Meropenem and imipenem resistance rates were 46.2% and 38.5%. Extended spectrum beta-lactamase (ESBL) production was present in 48 Klebsiella species (82.75%). Among ESBL positive Klebsiella species, the rate of meropenem and  imipenem resistance was 18.8% and ertapenem resistance was 45.9%. Extended spectrum beta-lactamase production was present in 27 (72.9%) Escherichia coli species. Among ESBL positive E.coli, the rate of meropenem and imipenem resistance was 7.4% and ertapenem resistance was 14.8%Conclusions: Emerging meropenem resistance in P. aeruginosa, higher rates of ertapenem resistance in ESBL positive ones in E.coli and Klebsiella species in pediatric nosocomial UTI are important  notifying signs for superbug infections.
Welcome to the First Issue of 2012
Authors: Sivan Yesha Y.
Published: August 2018

This year we focus on JVWR international expansion. This issue was led by David Herold from Hong Kong; our next issue is led by Ken Lim from Singapore; in May, 2012 JVWR hosts a Special Seminar on Virtuality as a Frontier for MIS Research as part of The Eleventh Wuhan International Conference on E-Business, in Wuhan, China.
Skull osteomyelitis as a rare complication of cat scratch disease
Authors: Rafee Yaseen , English B Keith
Published: August 2018

Bartonella henselae, the causative agent of cat scratch disease (CSD), is one of the most common causes of regional lymphadenitis in children. Other less common manifestations of B. henselae infection including fever of unknown origin, neuroretinitis, and osteomyelitis are being increasingly recognized. We describe a 3-year-old female with a recent history of typical CSD involving lymph nodes who developed osteomyelitis of the skull, a very rarely recognized complication of this infection.
Radiative feedbacks of dust in snow over eastern Asia in CAM4-BAM
Authors: Xie Xiaoning , Liu Xiaodong , Che Huizheng , Xie Xiaoxun , Li Xinzhou , Shi Zhengguo , Wang Hongli , Zhao Tianliang , Liu Yangang
Published: August 2018

Abstract. Dust in snow on the Tibetan Plateau (TP) could reduce the
visible snow albedo by changing surface optical properties and removing the
snow cover through increased snowmelt, which leads to a significant positive
radiative forcing and remarkably alters the regional energy balance and the
eastern Asian climate system. This study extends our previous investigation in
dust–radiation interactions to investigate the dust-in-snow radiative forcing
(SRF) and its feedbacks on the regional climate and the dust cycle over eastern Asia through the use of the Community Atmosphere Model version 4 with a Bulk Aerosol
Model parameterizations of the dust size distribution (CAM4-BAM). Our results
show that SRF increases the eastern Asian dust emissions significantly by
13.7 % in the spring, countering a 7.6 % decrease in the regional
emissions by the dust direct radiative forcing (DRF). SRF also remarkably
affects the whole dust cycle, including transport and deposition of dust
aerosols over eastern Asia. The simulations indicate an increase in dust
emissions of 5.1 %, due to the combined effect of DRF and SRF. Further
analysis reveals that these results are mainly due to the regional climatic
feedbacks induced by SRF over eastern Asia. By reducing the snow albedo over the
TP, the dust in snow mainly warms the TP and influences its thermal effects by
increasing the surface sensible and latent heat flux, which in turn increases
the aridity and westerly winds over northwestern China and affects the regional
dust cycle. Additionally, the dust in snow also accelerates the snow-melting process,
reduces the snow cover and then expands the eastern Asian dust source region, which results in increasing the regional dust emissions. Hence, a
significant feature of SRF on the TP is the creation of a positive feedback loop
that affects the dust cycle over eastern Asia.
Characterization of black carbon-containing fine particles in Beijing during wintertime
Authors: Wang Junfeng , Liu Dantong , Ge Xinlei , Wu Yangzhou , Shen Fuzhen , Chen Mindong , Zhao Jian , Xie Conghui , Wang Qingqing , Xu Weiqi , Zhang Jie , Hu Jianlin , Allan James , Joshi Rutambhara , Fu Pingqing , Coe Hugh , Sun Yele
Published: August 2018

Abstract. Refractory black carbon (BC) is a product from incomplete combustion of fossil fuel, biomass and biofuel, etc. By mixing with other species, BC can play significant roles in climate change, visibility impairment and human health. Such BC-containing particles in very densely-populated megacities, like Beijing, may have specific sources and properties, that are very important to the haze formation and air quality. In this work, we characterized exclusively the BC-containing particles only in urban Beijing, by using a laser-only Aerodyne soot particle aerosol mass spectrometer (SP-AMS), as a part of the Air Pollution and Human Health (APHH) 2016 winter campaign. The average mass ratio of coating-to-BC (RBC) was found to be ~ 5.0, much smaller than those of highly aged BC, indicating dominant contributions from primary emissions. Positive matrix factorization indeed shows the dominance of fossil fuel and biomass burning organics. Yet secondary species, including both sulfate, nitrate and oxygenated organic aerosol (OA) species, could have significant impacts on the properties of BC-containing particles, especially for ones with larger BC core sizes and thicker coatings. Analyses of the sources and diurnal cycles of organic coating reveal significant afternoon photochemical production of secondary OA (SOA), as well as the nighttime production of a portion of highly oxygenated OA. Besides SOA, photochemical production of nitrate, not sulfate, was very important. Further investigations on BC-containing particles at different periods show that, on average, more polluted periods would have more contributions from secondary species, and more thickly coated BC tended to associate with more secondary species, indicating the important role of chemical aging to the air pollution in urban Beijing during wintertime. However, for individual pollution events, aqueous-phase production of sulfate, nitrate and SOA might aggravate the pollution obviously under high relative humidity conditions, while sometimes local primary emissions (coal and biomass burning) could lead to serious and extremely polluted event too.
The 4.2-ka event, ENSO, and coral-reef development
Authors: Toth Lauren T. , Aronson Richard B.
Published: August 2018

Abstract. Variability of sea-surface temperature related to shifts in the mode of the El Niño–Southern Oscillation (ENSO) has been implicated as a possible forcing mechanism for the changes in global-scale, tropical and subtropical precipitation known as the 4.2-ka event. We explore records of coral-reef development and paleoceanography from the tropical eastern Pacific (TEP) to evaluate the potential impact of the 4.2-ka event on coral reefs. Our goal is to identify the regional climatic and oceanographic drivers of a 2500-year shutdown of vertical reef accretion in the TEP beginning 4.2 ka. The 2500-year hiatus represents ~ 40 % of the Holocene history of reefs in the TEP and was tied to increased variability of ENSO. When ENSO variability abated approximately 1.7–1.6 ka, coral populations recovered and vertical accretion of reef framework resumed apace. The 4.2-ka event appears to have suppressed coral populations and reef accretion elsewhere in the Pacific Ocean as well. Although the ultimate causality behind the global 4.2-ka event remains elusive, correlations between shifts in ENSO variability and the impacts of the 4.2-ka event suggest that ENSO played a role in climatic changes at that time, at least in the tropical and subtropical Pacific. We outline a framework for testing hypotheses of where and under what conditions ENSO may be expected to have impacted coral-reef environments around 4.2 ka. Although most studies of the 4.2-ka event have focused on terrestrial environments, we suggest that understanding the event in marine systems may prove to be the key to deciphering its ultimate cause.
A extensão universitária em debate: o curso pré-universitário como espaço de educação popular
Authors: Ingrassia Pereira Thiago , Gomes Tatiane Fernanda
Published: August 2018

Integrante do eixo que caracteriza a universidade brasileira junto com a pesquisa e o ensino, a extensão potencializa a relação da educação superior com a comunidade. O estudo em tela aborda as potencialidades de cursos pré-universitários populares em processos de aprendizagem, formação inicial de docentes e diálogo entre a universidade e sujeitos sociais diversos. Objetiva discutir a extensão universitária a partir de uma experiência de curso pré-universitário vinculada ao desafio da democratização do acesso à universidade. Embasado em princípios da educação popular de matriz freireana e em estudos e pesquisas sobre educação, universidade e extensão, este trabalho situa historicamente a extensão como uma prática dialógica, permeada por intencionalidade política, com desdobramentos epistemológicos e metodológicos no conhecimento acadêmico. Por meio de grupos focais com estudantes universitários(as) que atuam como educadores(as) em curso pré-universitário, a pesquisa desenvolvida explora as diferentes contribuições desse espaço para a formação docente e em processos de conscientização mais amplos que potencializam a reinvenção da universidade, tendo compromisso com cenários de transformação social. Dessa forma, sinaliza para o potencial de projetos de extensão universitária como mecanismos de produção e difusão de conhecimento emancipatório.
Preparing for High-Stakes Admissions Tests: A Moderation Mediation Analysis
Authors: Appelrouth Jed. I. , Moore DeWayne , Zabrucky Karen M. , Cheung Janelle H.
Published: August 2018

For decades researchers have examined the effects of SAT preparation, but only recently have they begun to explore the factors that inform successful test preparation (Appelrouth & Zabrucky, 2717). In their regression analysis of the factors of successful SAT preparation, Appelrouth, Moore, & Zabrucky (2015) found significant effects of homework completion, instructional hours, practice and official testing, distribution of study, and timing of test preparation. The current study builds upon that research in constructing a functional model of SAT preparatory factors. It was hypothesized that direct and indirect relationships would exist between preparatory factors, and that some of these relationships would be moderated by student characteristics such as gender and socioeconomic status. Archival data from 1,933 students were analyzed, and significant direct relations were reported between tutoring start time and the following variables: session distribution, individual tutoring hours, group tutoring hours, homework completion, number of official tests, number of practice tests and total SAT increase. Commencing test preparation earlier yielded positive direct and indirect effects, and session distribution, individual and group tutoring hours, and official SAT and practice SAT tests all mediated the relationship between start time and SAT score increase. School type and socioeconomic status moderated the relationship between start time and individual tutoring hours, and school type also moderated the relationship between homework completion and score increase. The results of this analysis have implications for the thousands of high schools and educational entities that offer SAT coaching programs. By encouraging earlier program start times, adequate instructional hours, distribution of sessions and practice effects, administrators can create more effective SAT preparation programs to serve their college-bound students.
Testis-sparing surgery: Experience in 13 patients with oncological and functional outcomes
Authors: Keske Murat , Canda Abdullah Erdem , Atmaca Ali Fuat , Cakici Ozer Ural , Arslan Muhammed Ersagun , Kamaci Davut , Balbay Mevlana Derya
Published: August 2018

Introduction: We present oncological and functional outcomes of patients who underwent testis-sparing surgery (TSS).

Methods: Overall, 13 patients were included. Mean patient age was 29.9±12.5 years. In five patients, TSS was performed for sequential bilateral testicular tumours. One patient underwent concurrent left radical orchiectomy and right TSS. In eight patients with normal contralateral testis, seven underwent left and one underwent right TSS.

Results: Mean pathological tumour size was 14.6±12.5 mm. Intraoperative frozen section evaluation of the mass was performed in eight patients that revealed benign lesions. No intraoperative tumour bed biopsies were taken in this patient group. Regarding the remaining five patients, intraoperative tumour bed biopsies were taken and testicular intraepithelial neoplasia (TIN) was reported in two (40%) patients; no local testicular radiotherapy was given postoperatively. Tumour pathology was malignant in all but one lesion, including Leydig cell tumour (n=1), seminoma(n=2), embryonal carcinoma (n=1), and adenomatoid tumour (n=1). During 47.2±22.5 months of followup, local recurrence was detected in one patient who underwent radical orchiectomy. No additional local recurrence or systemic metastasis was identified in other patients with malignant lesions. For patients with malignant tumours, of the three patients with a normal preoperative testosterone levels, testosterone level was normal in one patient (with no erectile dysfunction [ED]) and was decreased in two patients (with ED) following TSS. No ED was reported in the nine patients with benign lesions.

Conclusions: In carefully selected cases, TSS appears to be a safe, feasible procedure with adequate cancer control that could preserve sexual function.
Personality Factors, Academic Stress and Socio-economic Status as Factors in Suicide Ideation among Undergraduates of Ebonyi State University
Authors: Oginyi Ronald C. N. , Mbam Ofoke S. , Sampson Nwonyi , Chukwudi Ekwo J. , Nwoba Martin O. E.
Published: August 2018

The major purpose of this research was to investigate personality factors, academic stress and socio-economic status as factors in suicide ideation among undergraduates. The second purpose was to determine the extent to which personality factors, academic stress and socio-economic status could buffer the negative impacts of suicidal ideation. Cross sectional survey was used for the design of this study and hierarchical multiple regression was adopted for data analysis. Results showed that personality factors, academic stress and socio-economic status jointly and separately predicted suicidal ideation. The research findings implied that interventions strategies to improve social network and assessment of their personality factors may have positive outcome in reducing or preventing suicide ideation among undergraduates.
Patterns of Family Breeding Relationship with the Behavior of Violence at Students of the Secondary Stage
Authors: Maali Ibarhim Bajes
Published: August 2018

The study aimed at disclosing the relationship of family breeding with the behavior of violence at students of the secondary stage. The sample of study consisted of (311) male and female students had been chosen randomly from the community of study. To achieve the objectives of study, a scale of family breeding styles had been prepared, and have three dimensions, they are: the democratic style, the predominant style and the abandonment style.Results of study indicated that predominant style came in the first rank, the abandonment style in the second rank, and the democratic in the last rank. Results disclosed the effect of sex for the interest of males in the differences and behavior of violence, and non-existence of differences ascribed to the effect of the grade, and existence of positive connective relationship statistically significant between the behavior of the violence and the predominant style.
Anatomia da madeira e casca de Acacia tucumanensis Gris.
Authors: Marchiori José Newton Cardoso
Published: August 2018

The wood and bark anatomy of Acacia tucumanensis Gris. is described. Quantitative data from 33 different features of the secondary xylem are furnished, as well as photomicrographs and drawings of its structure. The presence of libriform fibres, simple perforation plates, paratracheal parenchyma and homogeneous rays, are important characteristics of the wood anatomy. The presence of septa in fibres and of rays with 3-4 cells wide, indicate the position of the species in the sub-genus Aculeiferum VassaI (= series Vulgares Benth.). Phloematic fibres in tangential bands, with 3-5 cells wide, and the irregular course of rays in the late bark, are the most conspicuous features of the bark structure. Photomicrographs of bark are also furnished.
My Favorite Lesson: Developing Intuition for Logarithms
Authors: Quintanilla John
Published: August 2018

Before students had ready access to computers and calculators, many developed intuition for the numerical values of logarithms through the use of printed tables of log values. One of my favorite lessons promotes this intuition for today's students through creative use of the laws of logarithms.
Exploring the Woolly Properties of Quadrilaterals
Authors: Chedister Matthew
Published: August 2018

To explore properties of quadrilaterals in a creative setting that focuses on discovery over memorization, assign your students the Wolves and Sheep problem.
Traveling at the Speed of Light
Authors: Beigie Darin
Published: August 2018

Students use scientific notation to calculate how long it takes light to travel a variety of astronomical distances and then interpret the significance of their findings.