bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Ce and Homogeneous Annealing on Microstructure and Deformation Performance of ZM21 Alloy
Authors: Li Quan , Zhu Wei Bo , Wang Si Ya , Jiang Xian Quan , Pan Fu Sheng
Published: April 2015

The rare earth element Ce was added in Mg-2.0Zn-1.0Mn magnesium alloys. And the homogenizing treatment and the extrusion deformation tests for the alloy were carried out. The effects of the Ce addition and homogenization on the microstructure and mechanical properties of Mg-2.0Zn-1.0Mn magnesium alloys were studied in the present investigation. The results showed that the addition of Ce can effectively refine the grain size of ZM21 alloy, improve the mechanical properties of magnesium alloy ZM21 and reduce the latent heat and solidification temperature range of the alloy. Homogenizing annealing treatment slightly affected the microstructure and mechanical properties of ZM21 alloy extrusion products but significantly affected the ZM21+Ce magnesium alloy. The fracture analysis indicated that the fracture of the two alloys was mixed fracture, while the fracture of magnesium alloy ZM21+Ce showed more ductile fracture feature.
Microstructural Evolution of Mg-4Al-2.5Ca Alloy during Solidification
Authors: Jiang Zhong Tao , Jiang Bin , Zhang Jian Yue , Xia Xiang Sheng , Pan Fu Sheng
Published: April 2015

In the present work, the microstructure evolution of Mg-4Al-2.5Ca alloy during solidification was investigated by means of scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and differential scanning calorimetry (DSC). The results showed that the as-cast microstructure was typical dendritic structure, consisting of α-Mg and the Al2Ca with a C15 structure formed at inter-dendritic regions. But during slow solidification, the sequence of phase formation of this alloy consisted of following stages: L→ L + α-Mg → L + α-Mg + (Mg, Al)2Ca → α-Mg + (Mg, Al)2Ca + Al2Ca → α-Mg + Al2Ca. Thermal analysis showed that the (Mg, Al)2Ca and Al2Ca phase separation temperature was about 520°C and 510°C respectively, which is different from thermodynamic calculation. With the temperature decreasing, the liquid (Mg, Al)2Ca phase with thick and continuous morphology transformed into lamellar-shaped eutectic phase, and parts of (Mg, Al)2Ca phase translated into Al2Ca phase with bone-shaped and needle-like.
Forming of the Battery Cell Packing in Extruded AZ31 Magnesium Alloys through Backward Extrusion
Authors: Wang Li Fei , Huang Guang Sheng , Liu Ding Kai , Pan Fu Sheng , Vedani Maurizio
Published: April 2015

Mg batteries have received increasing attention mainly because of their high volumetric capacity (3832 mAhcm−3). In order to form type NO.5 cell packing for Magnesium battery the finite element simulation by Deform 3D was carried out. Then backward extrusion was conducted on an AZ31 magnesium alloy at 300°C. The results show that battery cell packing with the wall of 0.35 mm can be formed through backward extrusion with an AZ31 Mg alloys. A significant grain size refining was resulted from hot BE, however, the microstructure in different positions of the Mg cell packing was inhomogeneous. At bottom of the packing, the microstructure was formed by equiaxial and relatively coarse grains. The wall of the Mg cell packing was made of much finer grains.
Influence of Cooling Method on the Microstructure and Stress Rupture Property of a Single Crystal Superalloy
Authors: Shi Zhen Xue , Liu Shi Zhong , Wang Xiao Guang , Li Jia Rong
Published: April 2015

The single crystal superalloy with [001] orientation were prepared by screw selecting method in the directionally solidified furnace. Three different cooling method, water cooling (WC), air cooling (AC) and furnace cooling (FC) were used after same solution treatment. Then these specimens received same two-step aging treatment. Influence of solution cooling method on the microstructure and stress rupture properties of the alloy under the test condition of 980 °C and 300 MPa was investigated. The microstructures of the samples were examined by scanning electron microscope (SEM). The results showed that the solution cooling method of heat treatment played an important role in the microstructure and stress rupture properties of the alloy. The size of γ′ phase and the width of the γ matrix channel of the alloy increased with decreasing cooling rate. The stress rupture properties of the alloy increased at first and decreased afterwards with decreasing cooling rate. The alloy with air cooling (AC) has the best stress rupture properties. The γ′ phase changed into a perfect raft structure during the stress rupture process of the specimens with AC method. However, the γ′ phase changed into a very irregular raft microstructure in the specimens with the water cooling (WC) and furnace cooling (FC) method. The micro-cracks in the specimen with irregular raft make the initiation and interconnection easier than that in the specimen with regular raft. Therefore, the alloy with AC method has optimum microstructure and stress rupture property.
Microstructures and Creep Behavior of As-Cast TiAl-Nb Alloy
Authors: Tian Su Gui , Wu Xiao Xia , Yu Hui Chen , Sun Hao Fang , Jiao Ze Hui
Published: April 2015

By means of creep properties measurement and microstructure observation, an investigation was carried out to study the creep behaviors of the as-cast TiAl-Nb alloy at temperature near 910 oC. Results showed that the microstructure of as-cast TiAl-Nb alloy consisted of γ/α2 phases with the lamellar feature, and the boundaries with irregular serrated configuration consisted of single γ phase, and located in between the lamellar γ/α2 phases with different orientations. The as-cast TiAl-Nb alloy displayed a better creep resistance at high temperature and longer creep life. Compared to α2 -Ti3Al phase, the γ phase possessed a weaker strength, therefore, the crack was easily initiated along the boundaries at about 45° angles relative to the stress axis, and propagated along the boundaries parallel to the orientation of lamellar γ/α2 phases up to the occurrence of creep fracture. Thereinto, the tearing edges formed on the surface of the fracture being inclined with the lamellar γ/α2 phases are attributed to the α2-Ti3Al phase with better strength hindering the crack propagation during creep.
Effect of Heat Treatment on Microstructure and High Temperature Wear Properties of High Boron Medium Carbon Alloy
Authors: Shi Xiao Li , Jiang Ye Hua , Li Zu Lai , Tan Jun
Published: April 2015

The microstructures and 500 °C high temperature wear properties of a high boron medium carbon alloy (HBMCA) quenched at 950 °C and then tempered at 500 °C were investigated, compared with a typical high speed steel (HSS). The results showed that the matrix structure of HBMCA after heat treatment was tempered sorbite. The content of herringbone-like and rodlike eutectic decreased. Hard phase precipitation (boron carbon compounds, e.g.M23 (C, B) 6, MB and M3B2) increased in the matrix. And the abrasion resistance of HBMCA after heat treatment at high temperature was 2.39 times of a typical HSS for roller. The wear mechanism of HSS at high temperature is a typical oxide fatigue wear mechanism, while as-quenched HBMCA is oxidation, adhesive wear mechanism.
Effect of Mo Addition on the Grain Growth of IN718 Alloy
Authors: Han Da Wei , Liu Fang , Jia Dan , Qi Feng , Yang Hong Cai , Sun Wen Ru , Hu Zhuang Qi
Published: April 2015

The effect of Mo addition on the grain growth of Inconel 718 alloy has been investigated. It was revealed that δ phase was precipitated at the grain boundaries when the Mo addition is in the range of 2.80% - 4.00%, while the Mo-bearing phase was precipitated at the grain boundaries when the Mo addition is in the range of 5.50% - 7.50%. By pinning the grain boundary, the grain boundary precipitate can effectively prevent the grain growths. So the grains grow rapidly with increase the solution temperature when the grain boundary precipitate is absent. The activation energy value for grain growth of IN718 alloys with different Mo addition is 210 - 255 kJ/mol and the grain growth mechanism is controlled by the self-diffusion. The grain growth exponent reduces with increasing Mo addition.
Effect of Rhenium on Microstructure of Directionally Solidified Ni-Based Superalloys with High Chromium Content
Authors: Li Xiu Hui , Liu Enze , Zheng Zhi
Published: April 2015

The microstructure of high Cr-containing directionally solidified Ni-based superalloys with different Re content were observed by scanning electron microscope. The segregation of alloying elements was also investigated by electron microprobe. According to the observation, the microstructure of as-cast samples included γ, γ', MC carbides and few (γ + γ') eutectic while that of heat-treated samples consists of γ, γ', MC carbides, M23C6 carbides and Re-containing carbides. With the addition of Re, some conclusions can be made as follows: Re exhibits the strongest degree of segregation to dendrite region and the segregation of Ti, Ta, Al become more serious. The γ' phase of as-cast samples is butterfly-like. For heat-treated samples, the γ' phase evolves from sphere to cube, the size of the γ' phase in the dendrite region decreases from 464 nm to 235 nm while the volume fraction of them barely changes.
Low Cycle Fatigue Behavior of Several Typical Powder Metallurgy Superalloys
Authors: Nai Qi Liang , Dong Jian Xin , Yao Zhi Hao
Published: April 2015

Powder metallurgy superalloy has become the preferred material of aircraft engine turbine disc and turbine damper due to advantages of uniform structure, fine grain size, high yield strength, high fatigue strength, etc. The low cycle fatigue behavior of several typical powder metallurgy superalloys at different holding time was studied in this work. The analysis of the microstructure, curves of Lga-LgNi/Nf, da/dN-a and da/dN-N indicated the ratio of crack preparation, initiation, propagation and final fracture in whole process fatigue failure. The mechanism of fatigue crack growth was investigated by comparing the chemical composition, microstructure, fracture morphology of different alloys.
Effect of Hafnium on the Microstructure and Creep Property of a Hot Corrosion Resistant Superalloy
Authors: Hou Jie Shan , Guo Jian Ting , Yuan Chao , Guo Yong An , Li Gu Song , Zhou Lan Zhang
Published: April 2015

The effects of the selective addition of Hafnium (Hf) on the grain boundary, phase, carbides and creep properties of experimented nickel superalloy after standard heat treatment and long-term exposure were investigated. Predicted by the Bayesian neural network, the creep life is prolonged with Hf content of 0-0.6 mass%, which is more effective at low stresses. The decrease of creep life of Hf free alloy after long term exposure was pronounced. Comparative study showed that the mainly small, coherent, blocky and closely spaced MC(2) and M23C6 carbides precipitated on the grain boundaries in the 0.4wt% Hf contained alloy, and that relatively larger, incoherent MC(1) carbides precipitated on the grain boundaries in the Hf free alloy. During long term thermal exposure, fine discrete M23C6 carbides decomposed from primary carbide, inducing a layer along the grain boundary, and the coarsening of grain boundary in Hf free alloy is more pronounced. At high stresses, the Hf-free alloy exhibited a stronger tendency of rafting than the 0.4Hf alloy, while the tendency of appearance of rafting was very similar at low stresses. However, Hf can render the alloy prone to the formation of σ phase, according to D-electrons method. Thus, the Hf content needs to be controlled to a suitable level.
Study on Hot Deformation Behavior of Cast-and-Homogenized Superalloy GH706
Authors: Yang Yan Hui , Liu Dong , Peng Jian Bing , Wang Jian Guo , Liu Guo Wei , Hu Yang
Published: April 2015

Hot deformation behavior of cast-and-homogenized GH706-ingot material was studied in this work. Isothermal uniaxial compression tests were performed at temperatures (°C): 990, 1020, 1050, 1080 and 1100 with strain rates (s-1): 0.01, 0.1 and 1. The stress-strain curves as well as changes in microstructures of various hot deformed specimens were analyzed. Inhomogeneous microstructures were found in the specimens and the flow curves were resulted from the comprehensive functions of microstructures change in all part of the specimens. The constitutive relationship of alloy GH706 has been established by linear regression analysis of the experimental data taken from the Arrhenius equations as a model. Then hot compression tests were carried out to estimate the allowable reductions, and 52.5% and 50.6% are suggested as the allowable reductions during cogging processing of GH706 alloy in each blow at 1110°C and 1130°C.
Preparing Amorphous/Nanocrystalline TiNbZrTaFe Powder by Mechanical Alloying
Authors: Zou Li Ming , Cai Yi Xiang
Published: April 2015

(Ti69.7Nb23.7Zr4.9Ta1.7)100-xFex (x=0, 2, 6, and 10) nanocrystalline, nanocomposite and amorphous powders were synthesized by mechanical alloying from blended element powder. The structural transition for the milled powders was confirmed by X-ray diffraction (XRD). Results shows with the increasing Fe content in alloy system, the glass forming ability become larger. Only for x=10, it can obtain nearly completely amorphous structure with wide super cooled liquid region (△Tx =122 K). For x=2 and 6, residual nanocrystals of the β-Ti structure dispersed in the amorphous matrix. For x=0, the milled powder has full nanocrystalline structure. These as-milled powders offer the potential to fabricating the bulk glass material or nanocrystal/glass matrix composites by powder metallurgy for biomedical use.
Corrosion Behavior of Tungsten Copper Alloy Produced by Infiltration Sintering
Authors: Lv Bo , Zhang Da Tong
Published: April 2015

In this paper, W80CuNi0.3 alloy was prepared by cold isostatic pressing (CIP) and infiltration sintering, and its corrosion behavior was investigated by neutral salt spray accelerated test, immersion test and electrochemical measurement. It turned out that in the neutral salt spray and immersion test,the mass loss and corrosion rate of W80CuNi0.3 were far lower than those of 45 steel. The corrosion mainly occurs in the bonding phase of Cu, and the initial corrosion form of W80CuNi0.3 was pitting, the main reason of W80CuNi0.3 corrosion was Cl- erosion. The polarization curves analysis showed that compared with 45 steel, W80CuNi0.3 alloy had higher corrosion potential and lower corrosion current. Therefore, W80CuNi0.3 alloy are prone to stable passivation, so it has superior corrosion resistance.
Effect of Pre-Quenching Process on Microstructure and Mechanical Properties in a Nb-Microalloyed Low Carbon Q-P Steel
Authors: Zhang Jun , Ding Hua , Zhao Jing Wei
Published: April 2015

A refined microstructure consisting of martensite and retained austenite at room temperature has been produced in a Nb-microalloyed low carbon Si-Mn steel by a novel heat-treatment, pre-quenching prior to quenching and partitioning processes (Q&Q-P). The results showed that compared with the conventional quenching and partitioning steel the mechanical properties of steel obtained by the novel treatment have been significantly improved, with a good combination of ultimate tensile strength (1000MPa) and total elongation (above 30%). Meanwhile, the volume fraction of retained austenite has been increased. It was found that the improvement of mechanical properties was mainly attributed to the enhanced TRIP effect due to the relatively high fraction of metastable retained austenite at room temperature. The increased stability of austenite results from the C and Mn partitioning during inter-critical annealing, which increased the chemical stability of austenite. The formation of refined austenite at inter-critical annealing also had a positive effect on the stability of the austenite. As a consequence, the volume fraction of retained austenite at room temperature was significantly increased. Compared with the Q-P steel, the Q&Q-P steel exhibited higher work hardening exponents during the stage of TRIP effect and had the higher ductility.
Effect of Rolling Process on Impact Toughness in High Strength Low Carbon Bainitic Steel
Authors: Yang Xiao Long , Tan Xiao Dong , Xu Yun Bo , Hu Zhi Ping , Yu Yong Mei , Wu Di
Published: April 2015

Based on TMCP and UFC technology, the microstructures and impact toughness of low carbon bainitic steel were studied in this paper. The bainite morphology and fracture surfaces of Charpy impact specimens were observed by SEM, and mechanical properties of bainitic steel were measured by tensile and impact test. The results showed that the yield and tensile strengths of steel were 804MPa and 1015MPa, and elongation was 15.7% when the rolling was finished in the austenite recrystallization region. The steel rolled below Tnr temperature obtained tht yield strength of 930 MPa, tensile strength of 1090 MPa and elongation of 16.2%. However, the impact toughness was deteriorated in the steel rolled above Tnr temperature while the excellent impact toughness existed in the steel rolled below Tnr temperature. The impact toughness of steel rolled below Tnr temperature was 140J at-60°C, while the impact toughness of 15J at the same temperature was obtained for the steel rolled above Tnr temperature. The large cleavage fracture region on the fracture surface occured with the decrease of tested temperature in the steel rolled above Tnr temperature and inevitably reduced the impact toughness, while the main ductile fracture existed in the steel rolled below Tnr temperature at the same temperature. The rolling process of steel can strongly affect impact toughness of low carbon bainitic steel. Hence, the different rolling processes can adjust the occurrence of cleavage fracture and ductile fracture in order to improve the impact toughness.
Microstructure and Mechanical Properties of a Cold-Rolled Medium Manganese Steel with Delta Ferrite
Authors: Hu Zhi Ping , Xu Yun Bo , Tan Xiao Dong , Yang Xiao Long , Yu Yong Mei
Published: April 2015

In this paper, a quenching and tempering process was applied to the cold-rolled medium Mn steel with the delta ferrite (Fe-0.18C-6.4Mn-2.8Al). Microstructure characterization was carried out by means of optical microscope, scanning electron microscope (SEM) equipped with electron backscattered diffraction (EBSD) and transmission electron microscope (TEM). Mechanical properties tests were carried out by uniaxial tension tests. The microstructure characterization results revealed that the steel possessed a complex microstructure composed of three phases (austenite, martensite and delta ferrite). The volume fractions of austenite before and after a deformation were determined by X-ray diffraction (XRD). The XRD results indicated that the amount of austenite reached up to 20 vol.% and the TRIP effect occurred quite apparently. The mechanical property results showed that the steel possessed adequate ultimate tensile strength of 800MPa and excellent elongation of 25%. The outstanding combination of strength and ductility with the product of strength and elongation (PSE) reaching up to over 20GPa% indicates that the steel has a bright application prospect.
Effect of Cooling Procedure on Tensile and Charpy Impact Properties of Cr-Mo Ultra-High Strength Steel
Authors: Xie Hui , Du Lin Xiu , Hu Jun
Published: April 2015

The effect of cooling procedure on the transformation behavior of low-carbon Cr-Mo microalloyed steel was investigated by using microstructural observations, mechanical properties and impact fractographs. Three steel plates were adopted under three different cooling rates, and their microstructure, tensile and impact properties were evaluated. The results indicated that the strength of experimental steels was increased and the impact toughness was decreased with decreasing the coiling temperature. Steel A consisted of granular bainite, coarse bainitic ferrite lath and M/A constituent subjected to a coiling temperature of 560 oC. The yield strength, tensile strength and impact energy of 1/2-size Charpy impact at-20 oC were 740MPa, 1020MPa, and 33.5J, respectively, which were imperfect in strength. The effects of coiling temperature were potent on the refinement of microstructure and the size of M/A constituents. Steel B consisted of a small amount of lath bainite, fine M/A constituents and bainitic ferrite lath subjected to a lower coiling temperature of 520 oC. The yield strength, tensile strength and impact energy of 1/2-size Charpy impact at-20°C were 840MPa, 1030MPa, and 30.7J, respectively. However, steel C was composed of lath bainite and lath martensite subjected to the lowest coiling temperature of 380 oC (slightly above Ms point). The yield strength, tensile strength and impact energy of 1/2-size Charpy impact at-20 oC were 985MPa, 1200MPa and 22.5J, respectively, which could meet the demand of ultra high strength structural steel applications.
Influences of High Temperature Treatment of C/C on the Mechanical Properties of C/C-SiC Composites
Authors: Lin Dong , Wang Jing , Zhang Chang Rui , Cao Ying Bin , Liu Rong Jun
Published: April 2015

C/C-SiC composite as low expansion material for space opto-mechanical structures was prepared by gaseous silicon infiltration after high temperature treatment (HTT) on C/C. 2000°C and 2400°C were selected as the treatment temperatures for C/C to study the influences on the properties of C/C-SiC composite. The graphitization level of amorphous C in C/C was improved by HTT. The porosity of C/C increased from 32.88% to 34.25% (2000°C) and 41.06% (2400°C) respectively. In addition, a higher HTT temperature led to a higher density of C/C-SiC composite and a lower SiC content. Furthermore, the mechanical properties and coefficient of thermal expansion (CTE) of the composite decreased as the temperature increased. After 2000°C HTT, the CTE of C/C-SiC composite decreased to-0.055×10-6·K-1 and the mechanical properties (218 MPa) could meet the application demand at the same time.
Effect of Ni Alloying on the Corrosion Resistance of 355MPa High Weather-Resistant Steel
Authors: Hou Z.R. , Yi H.L. , Zhao X.M.
Published: April 2015

Based on the 355MPa high weather-resistant steel, three different kinds of high weather-resistant steels were designed by varying the content of Ni. The the corrosion resistance of the high weather-resistant steel as well as the influence of Ni content on the corrosion resistance were studied in the present investigation. The results of the cycle corrosion tests indicated that with the addition of Ni, the corrosion resistance was improved to some extent. The rust layer of the weathering steel was composed of α-FeOOH and γ-FeOOH at the beginning of corrosion, and the α-FeOOH turned to γ-FeOOH which enhanced the corrosion resistance.
Dynamic Behaviors of near β-Type Ti-5Al-5Mo-5V-3Cr Titanium Alloys under High Strain Rate
Authors: Wang Yan Ling , Hui Song Xiao , Ye Wen Jun , Liu Rui
Published: April 2015

The mechanical properties and fracture failure behavior of the near β-type Ti-5Al-5Mo-5V-3Cr-X (X = 1Fe or 1Zr) titanium alloys were studied by Split Hopkinson Pressure Bar (SHPB) experiment under the dynamic loading conditions at a strain rate of 1.5 × 103 s-1–5.0 × 103 s-1. Results showed that the SHPB specimen fractured in the direction of maximum shearing stress at an angle of 45° with the compression axis. The fracture surface revealed the shear and tension zones with cleavage steps and parabolic dimples. Severe early unloading was observed on the Ti-5553 alloy under a strain rate of 4,900 s-1 loading condition, and the dynamic property of the Ti-55531Zr alloy was proved to be the optimal.
Influence of Yb2O3 and Y2O3 on the Mechanical Properties of Porous Si3N4 Ceramics
Authors: Cheng Chuan Bing , Fan Run Hua , Liu Fu Tian , Wang Chong Hai , Wang Hong Sheng , Zhou Chang Ling
Published: April 2015

Using Yb2O3 or Y2O3 as s single sintering additive, the porous Si3N4 ceramics with excellent mechanical properties were successfully fabricated by pressureless sintering. The influence of Y2O3 and Yb2O3 on the microstructure and mechanical properties of porous Si3N4 ceramics was investigated. The results show that both sintering additives can effectively promote α to β phase transformation, and microstructures with elongated β-Si3N4 grains interlocking and superimposing on each other can be obtained. However, sinterability, phase transformation and mechanical properties of the porous Si3N4 ceramics with Yb2O3 were more excellent than the ceramics with Y2O3. The specimens with Yb2O3 had high aspect ratio β-Si3N4 grains, and formed the high melting crystalline Yb4Si2N2O7.
Phosphatase PTPN4 Preferentially Inhibits TRIF-Dependent TLR4 Pathway by Dephosphorylating TRAM
Authors: Huai Wanwan , Song Hui , Wang Lijuan , Li Bingqing , Zhao Jing , Han Lihui , Gao Chengjiang , Jiang Guosheng , Zhang Lining , Zhao Wei
Published: April 2015

TLR4 recruits TRIF-related adaptor molecule (TRAM, also known as TICAM2) as a sorting adaptor to facilitate the interaction between TLR4 and TRIF and then initiate TRIF-dependent IRF3 activation. However, the mechanisms by which TRAM links downstream molecules are not fully elucidated. In this study, we show that TRAM undergoes tyrosine phosphorylation upon TLR4 activation and that is required for TLR4-induced IRF3 activation. Protein tyrosine phosphatase nonreceptor type 4 (PTPN4), a protein tyrosine phosphatase, inhibits tyrosine phosphorylation and subsequent cytoplasm translocation of TRAM, resulting in the disturbance of TRAM–TRIF interaction. Consequently, PTPN4 specifically inhibits TRIF-dependent IRF3 activation and IFN-β production in TLR4 pathway. Therefore, our results provide new insight into the TLR4 pathway and identify PTPN4 as a specific inhibitor of TRIF-dependent TLR4 pathway. Targeting PTPN4 would be beneficial for the development of new strategy to control TLR4-associated diseases without unwanted side effects.
Elevated serum levels of macrophage migration inhibitory factor and stem cell growth factor β in patients with idiopathic and systemic sclerosis associated pulmonary arterial hypertension
Authors: Stefanantoni K. , Sciarra I. , Vasile M. , Badagliacca R. , Poscia R. , Pendolino M. , Alessandri C. , Vizza C.D. , Valesini G. , Riccieri V.
Published: April 2015

Pulmonary arterial hypertension (PAH) can be idiopathic or secondary to autoimmune diseases, and it represents one of the most threatening complications of systemic sclerosis (SSc). Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine with proinflammatory functions that appears to be involved in the pathogenesis of hypoxia-induced PH. In SSc patients, high serum levels of MIF have been associated with the development of ulcers and PAH. Stem cell growth factor β (SCGF β) is a human growth factor that, together with MIF, is involved in the pathogenesis of chronic spinal cord injury. The aim of our study was to measure serum levels of MIF in patients with idiopathic and SSc-associated PAH. We enrolled 13 patients with idiopathic PAH and 15 with SSc-associated PAH. We also selected 14 SSc patients without PAH and 12 normal healthy controls, matched for sex and age. PAH was confirmed by right hearth catheterism (mPAP>25 mmHg). MIF and SCGF β levels were measured by ELISA. We found significantly higher circulating levels of MIF and of SCGF β in patients with idiopathic PAH (P=0.03 and P=0.004) and with PAH secondary to SSc (P=0.018 and P=0.023) compared to SSc patients without PAH. Higher levels of MIF were found in those patients with an higher New York Heart Association (NYHA) class (P=0.03). We can hypothesize that MIF and SCGF β are able to play a role in PAH, both idiopathic or secondary, and in the future they may be evaluated as useful biomarkers and prognostic factors for this serious vascular disease.
A Rare Occurrence of Neonatal Nephroblastoma in Sub-Saharan Africa: A Case Report and Management in a Resource-Constrained Region
Authors: Matondo Féfé Khuabi , Budiongo Aléine Nzazi , Tady Bruno Muyala , Lebwaze Bienvenu Massamba , Lelo Michel Tshikwela , Gini-Ehungu Jean Lambert , Mwepu Idesbald , Nkidiaka Emmanuel Dimbu , Aloni Michel Ntetani
Published: April 2015

Neonatal nephroblastoma has been rarely reported in African neonate. A premature newborn (a 5-day-old male) was transferred with a history of neonatal abdominal mass. Ultrasonography revealed 75×46 mm, well-defined mass with mixed echogenicity replacing the right kidney. The patient underwent right radical nephrectomy and the tumor was confirmed to be a blastemal predominant Wilms’ tumor by the histopathological examination and has an unfavorable prognosis. The child died secondary to multiple organ failure, three days after surgery. Our case report serves to remind us the need to bear in mind the possibility of the diagnosis of neonatal nephroblastoma in neonate with renal mass.
A Case of Lymphoepithelioma-like Carcinoma in the Uterine Cervix
Authors: Takebayashi Kanetoshi , Nishida Masakazu , Matsumoto Harunobu , Nasu Kaei , Narahara Hisashi
Published: April 2015

Lymphoepithelioma-like carcinoma occurring in the reproductive organs is a rare variant of squamous cell carcinoma, and this tumor of the uterine cervix accounts for 0.7% of all primary cervical uterine neoplasms. Associations with Epstein-Barr virus (EBV) and human papilloma virus (HPV) have been demonstrated in some studies. Some investigators suggested that EBV has an important role in the initiation of lymphoepitheliomalike carcinoma in Asian women. Here we report the case of a 45-year-old Japanese woman, gravida 2 and parity 2. She was admitted due to severe atypical genital bleeding caused by uterine cervical cancer. A >60-mm tumor was detected at the uterine cervix, and no distal metastasis or swallowing of lymph nodes was revealed by magnetic resonance imaging and a computed tomography scan. The cervical cancer stage FIGO Ib2 was diagnosed, and a radical hysterectomy was performed for this malignant tumor. The in situ hybridization for EBV was negative. HVP infection was strongly suspected because the squamous cell carcinoma was observed macroscopically in the uterine cervix. The prognosis of uterine lymphoepithelioma-like carcinoma is thought to be better than those of other cervical cancer types, but careful follow-up at fixed intervals is recommended. The patient has been followed up for 4 months since her surgery, and no evidence of recurrence has been detected.
Whole Exome Sequencing of a Patient with Metastatic Hidradenocarcinoma and Review of the Literature
Authors: Gupta Eva , Guthrie Kimberly J. , Krishna Murli , Asmann Yan , Parker Alexander S. , Joseph Richard W.
Published: April 2015

Hidradenocarcinoma is a rare malignancy of the sweat glands with only a few cases reported in literature. The management of these tumors is based on the extent of disease with local disease managed with surgical resection. These can tumors carry a high potential of lymphatic and vascular spread and local and distant metastases are not uncommon. Given the rarity of the tumor and lack of genetic and clinical data about these tumors, there is no consensus on the proper management of metastatic disease. Here in we report the first case of metastatic hidradenocarcinoma with detailed molecular profiling including whole exome sequencing. We identified mutations in multiple genes including two that are potentially targetable: PTCH1 and TCF7L1. Further work is necessary to not only confirm the presence of these mutations but also to confirm the clinical significance.
Chemical and mineralogical characteristics of milled coal, ashes, and stack-emitted material from Unit No. 5, Battle River coal-fired power station, Alberta, Canada
Authors: Goodarzi F , Peel W P , Huggins F E , Brown J R , Charland J -P , Percival J
Published: April 2015

Elemental compositions of milled-coal, bottom and fly ash, and stack flue gas were determined in order to assess the amounts of elements of environmental concern emitted from the stack at Unit No. 5, Battle River coal-fired power station in central Alberta. The
species of arsenic (As+3,+5), chromium (Cr+3,+6) and nickel (Ni0,+2) in coal and ash, and stack-emitted polyaromatic hydrocarbons were also determined. The study indicates that, at 0.05 tonnes/year, emissions of hazardous air pollutants, such as arsenic, cadmium, mercury, lead, and selenium, are
low. The total emissions of other elements (Be, Ba, Co, Cr, Cu, Mn, Mo, Ni and V) are 1.0 tonnes/year, much less than the legislated total emission level of 25 tonnes/year for all these elements, or 10 tonnes/year for any individual element. Radionuclide (thorium and uranium) emissions are 17
kg/year. The activity of the 235U series is below the detection limit for all samples analyzed. The emissions of polyaromatic hydrocarbons (PAHs) are low. Three PAHs (phenanthrene, fluoranthrene, and pyrene) were detected at low concentrations in stack gas. Fly ash is ferrocalcsialic and contains
both nonmetallic and metallic microspheres and angular feldspar fragments. Fly ash collected from the inlet and hopper of the electrostatic precipitators contains plerospheres (spheres in spheres). There are no plerospheres in the particles emitted from the stack, indicating that some of the
microspheres are retained within the power plant.
Elements removed by ammonium acetate from milled coal are limited to As, Ba, Be, Co, Mn and Na, indicating that they are associated with exchangeable sites in an organic fraction, carboxylic group (as chelate) and carbonates. Most elements in milled coal are leached by HCl. The ion-exchangeable
elements in bottom ash and fly ash consist of Ba, Be, Co, Cr, Cu, Mn, Na, and Ni. All elements are leached by HCl from bottom and fly ashes, and most of the elements have their highest leachate in this stage. The study on the speciation of elements suggests that arsenic in milled coal is present as
arsenical pyrite (As+3) and is associated with coal macerals. Arsenic in bottom and fly ashes predominantly consists of less toxic As+5 (arsenate) species. Chromium and nickel in milled coal, bottom and fly-ash samples are present predominantly as Cr+3 that is essential to health, and nontoxic Ni+2
in co-ordination with oxygen.
Facilitative and obstructive factors in the clinical learning environment: Experiences of pupil enrolled nurses
Authors: Lekalakala-Mokgele Eucebious , Caka Ernestine M.
Published: April 2015

Background: The clinical learning environment is a complex social entity that influences student learning outcomes in the clinical setting. Students can experience the clinical learning environment as being both facilitative and obstructive to their learning. The clinical environment may be a source of stress, creating feelings of fear and anxiety which in turn affect the students’ responses to learning. Equally, the environment can enhance learning if experienced positively.Objectives: This study described pupil enrolled nurses’ experiences of facilitative and obstructive factors in military and public health clinical learning settings.Method: Using a qualitative, contextual, exploratory descriptive design, three focus group interviews were conducted until data saturation was reached amongst pupil enrolled nurses in a military School of Nursing.Results: Data analysed provided evidence that acceptance by clinical staff and affordance of self-directed learning facilitated learning. Students felt safe to practise when they were supported by the clinical staff. They felt a sense of belonging when the staff showed an interest in and welcomed them. Learning was obstructed when students were met with condescending comments. Wearing of a military uniform in the public hospital and horizontal violence obstructed learning in the clinical learning environment.Conclusion: Students cannot have effective clinical preparation if the environment is not conducive to and supportive of clinical learning, The study shows that military nursing students experience unique challenges as they are trained in two professions that are hierarchical in nature. The students experienced both facilitating and obstructing factors to their learning during their clinical practice. Clinical staff should be made aware of factors which can impact on students’ learning. Policies need to be developed for supporting students in the clinical learning environment.
Perspectives on family and youth ministry embedded in the missio Dei – an African perspective
Authors: Knoetze Johannes
Published: April 2015

The largest part of the population in Africa is classified as youth, but most churches in Africa are still without a contextual African family and youth theology. In many instances, the first question which is asked by churches is how to reach families and youth, without understanding who the ones are that are involved and what the calling is of those who participate in the ministry, as well as who those families and youth are that are ministered too. This article will contribute to the theological understanding of why a family and youth ministry specific for Africa is important. Since identity is a key issue in family and youth ministry, the article takes a short reality check on African family and youth ministry in relation to identity. A missional hermeneutical key is proposed and attention is given to the what question. In the last part, family and youth ministry is discussed from the missio trinitatis Dei perspective to give perspectives on the how, who and what questions.Perspektiewe op ’n gesins- en jeugbediening vanuit die missio Dei – ’n Afrika-perspektief. Die meeste kerke in Afrika beskik nie oor ’n kontekstuele teologie vir ’n gesins- en jeugbediening spesifiek vir Afrika nie, alhoewel die grootste gedeelte van die bevolking in Afrika as jeuggeklassifiseer word. Wanneer daar aan gesins- en jeugbediening gedink word, is die eerste vraag wat gewoonlik gevra word hoe dit gedoen word, sonder om duidelikheid te verkry oor wie by die bediening betrokke is en wat die roeping van die bedienaars is, asook wie die gesinne en die jeug is wat bedien word. Hierdie artikel wil ’n bydrae lewer tot die teologiese verstaan van waarom ’n eie gesins- en jeugbediening vir Afrika belangrik is. Aangesien die vraag oor identiteit wesenlik in gesins- en jeugbediening is, word oorsigtelik na omstandighede in Afrika gekyk om daardeur gesinne en die jeug se identiteit binne ’n bepaalde konteks te plaas. ’n Missionale hermeneutiek word as sleutel voorgestel om die roepings- of wat-vraag te beantwoord. Laastens word gesins- en jeugbediening in Afrika vanuit die missio trinitatis Dei bespreek as ’n perspektief om die hoe, wie en wat-vrae te beantwoord.
Teologie van die koninkryk (Basileiologie)? Teologies nagedink oor die plek en betekenis van die koninkryk van God in die teologie en die kerk
Authors: Van Wyk Jan H.
Published: April 2015

Hierdie artikel is ’n poging om aan te toon dat daar ’n groot leemte bestaan in die wyse waarop die klassieke leerstukke in dogmatiek in die verlede hanteer is, omdat dit ’n sentrale tema soos die koninkryk van God óf volkome geïgnoreer, óf totaal onderbelig het. Hierdie leemte word vervolgens nader ondersoek. Eers word aandag gegee aan die eskatologiese modelle wat in hierdie verband ontstaan het. Daarna word op die sentraliteit van die tema van die koninkryk in die Ou en Nuwe Testament gefokus en hierna word op die dinamiese uitwerking daarvan gelet wat dit op die samelewing behoort te hê. Die konklusie waartoe die outeur kom, is dat die tema van die koninkryk van God in die geheel gesien in die kerk en in die teologie totaal onderbeklemtoon was en steeds is. Vir ’n relevante kerkbeskouing (ekklesiologie) kan dit ’n groot bevryding bring indien die fokus van die kerk na die (gekome en komende) ryk van God verskuif. Die dogmatiek benodig ’n afsonderlike locus wat oor die Basileiologie handel.Theology of the kingdom (Basileiology)? Theological reflections on the place and role of the kingdom of God in church and theology. This article is an attempt to demonstrate that there is a great void in the way in which classical doctrine was treated in dogmatics in the past, since it either completely ignored a central theme like the kingdom of God, or shed altogether insufficient light on it. This void will subsequently be investigated more closely.Firstly, attention is given to the eschatological models which came into being for it. Next, the focus is on the centrality of the theme of the kingdom in the Old and New Testament after which its dynamic effect on society is pointed out.The conclusion reached by the author is that the theme of the kingdom of God was and is on the whole underemphasised in the church and in theology. For a relevant view of the church (ecclesiology) it could be liberating if the church shifted its focus to the kingdom of God (that has come and is coming). Dogmatics needs a separate locus dealing with Basileiology.
Statutory compliance in assets disposal practices in the public sector: Evidence from Ghana
Authors: Atiga Oswald , Adafula Christopher J. , Nyeadi Joseph D.
Published: April 2015

Background: This article examined the unserviceable assets disposal practices of five polytechnics (tertiary educational institutions) in Ghana.Objectives: The aim was to determine the extent of statutory compliance, and the degree to which value for money was achieved in actual disposal.Method: A survey was conducted using interviewer-administered questionnaires containing five-point likert scale test items. Descriptive statistics and a one-way analysis of variance (ANOVA) were employed to analyse the data.Results: The study results showed that a limited number of polytechnics had internal policies to operationalise statutory procurement legislation. Top management demonstrated very clear understanding of procurement legislation whilst senior-level managers displayed mixed levels of understanding. The section of the legislation dealing with disposals and the procedures pertaining thereto is perceived to be difficult to implement and does not promote value for money. Top management’s interference in auctions was the toughest challenge in the process, whilst public auction was the predominant method used in assets disposal.Research limitations: The research was carried out in only five polytechnics. This study could be replicated in other tertiary institutions or in other sectors outside higher education.
Review of the Umthombo Youth Development Foundation scholarship scheme, 1999–2013
Authors: Ross Andrew , MacGregor Gavin , Campbell Laura
Published: April 2015

Introduction: Staffing of rural and remote facilities is a challenge throughout the world. Umthombo Youth Development Foundation (UYDF) has been running a rurally based scholarship scheme since 1999.The aim of this review is to present data on the number of students selected, their progress, graduation and work placement from inception of the scheme until 2013.Methods: Data were extracted from the UYDF data base using a data collection template to ensure all important information was captured.Results: Since 1999, 430 rural students across 15 health disciplines have been supported by UYDF. The annual pass rate has been greater than 89%, and less than 10% of students have been excluded from university. All graduates have spent time working in rural areas (excluding the 32 currently doing internships) and 72% (52/73) of those with no work-back obligation continue to work in rural areas.Discussion and conclusion: The UYDF model is built around local selection, compulsory academic and peer mentoring and social support, comprehensive financial support and experiential holiday work. The results are encouraging and highlight the fact that rural students can succeed at university and will come back and work in rural areas. With 46% of the South African population situated rurally, greater thought and effort must be put into the recruitment and training of rural scholars as a possible solution to the staffing of rural healthcare facilities. The UYDF provides a model which could be replicated in other parts of South Africa.
A comparative cost analysis of picture archiving and communications systems (PACS) versus conventional radiology in the private sector
Authors: Moodley Indres , Moodley Sivani
Published: April 2015

Background: Radiology is rapidly advancing, with a global transition to digital imaging technology to improve productivity and enhance communication. The major challenge confronting radiology practices is to demonstrate cost savings and productivity gains when a picture archiving and communication system (PACS) is established.Aim: To undertake an incremental cost analysis of PACS compared with conventional radiology to determine productivity gains, if any, at two private hospitals in Durban.Method: An incremental cost analysis for chest radiographs, computed tomography and magnetic resonance imaging brain scans with and without contrast were performed. The overall incremental cost for PACS in comparison with a conventional radiology site was determined. The net present value was also determined to evaluate the capital budgeting requirements for both systems.Results: The incremental cost of both capital and the radiology information system for installing PACS shows an expected increase. The incremental PACS image cost shows a reduction.Conclusion: The study provides a benchmark for the cost incurred when implementing PACS. It also provides a decision framework for radiology departments that plan to introduce PACS and helps to determine the feasibility of its introduction.
Incidentally Detected Mediastinal Vascular Anatomical Variants on PET-CT: A Pictorial Essay
Authors: Paidipati Kathyayini Gopalkrishna Murthy , Kashyap Raghava , Tadimeti Hima , Peyyeti Mahidhar
Published: April 2015

Positron emission tomography with computed tomography (PET–CT) is an integral part of oncology practice in the current-day scenario. The hybrid anatomical and metabolic imaging information in this imaging modality provides access to a wealth of incidental findings which can have implications in the management of the patient, especially when surgical options are being considered. In this pictorial essay, we present incidentally detected mediastinal vascular anomalies on PET–CT, along with a review of associated literature.
Targeting modulation of noradrenalin release in the brain for amelioration of REMS loss-associated effects
Authors: Singh Abhishek , Nath Mallick Birendra
Published: April 2015

Rapid eye movement sleep (REMS) loss affects most of the physiological processes, and it has been proposed that REMS maintains normal physiological processes. Changes in cultural, social, personal traits and life-style severely affect the amount and pattern of sleep, including REMS, which then manifests symptoms in animals, including humans. The effects may vary from simple fatigue and irritability to severe patho-physiological and behavioral deficits such as cognitive and behavioral dysfunctions. It has been a challenge to identify a molecule(s) that may have a potential for treating REMS loss-associated symptoms, which are very diverse. For decades, the critical role of locus coeruleus neurons in regulating REMS has been known, which has further been supported by the fact that the noradrenalin (NA) level is elevated in the brain after REMS loss. In this review, we have collected evidence from the published literature, including those from this laboratory, and argue that factors that affect REMS and vice versa modulate the level of a common molecule, the NA. Further, NA is known to affect the physiological processes affected by REMS loss. Therefore, we propose that modulation of the level of NA in the brain may be targeted for treating REMS loss-related symptoms. Further, we also argue that among the various ways to affect the release of NAlevel, targeting α2 adrenoceptor autoreceptor on the pre-synaptic terminal may be the better option for ameliorating REMS loss-associated symptoms.