bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Thermal Exposure on the Microstructure, Surface Stability and Strength of a New Fe-Ni-Base Superalloy for A-USC Applications
Authors: Zhong Zhi Hong , Gu Yue Feng , Yuan Yong , Shi Zhan , Wu Yu Cheng
Published: April 2015

A low-cost, high-creep strength wrought Fe‒Ni-base superalloy for 700 °C advanced ultra-supercritical coal-fired power plant applications has been developed. The microstructural stability of this alloy during long-term exposures at 700 °C‒750 °C for up to 10000 h was investigated by SEM and TEM. The correlation between the microstructure evolution and the mechanical properties was studied. The experimental results showed that the major precipitates in the alloy were spherical γ′, MC and discrete M23C6 after the long-term exposure at 700 °C and 750 °C and no harmful phases, such as σ phase and η phase, were observed. The amount of M23C6 increased with exposure time at 700 °C while it decreased at 750 °C. During thermal exposure γ′ coarsened with increasing the exposure time and exposure temperature. Alloy showed good oxidation resistance due to the formation of external layer of Cr2O3. The yield strength of the alloy increased at first and then decreased with increasing exposure time at 700 °C, but it decreased gradually with increasing exposure time at 750 °C. The relationship between yield strength and the dominant deformation mechanisms of the alloy was discussed.
Creep Behavior of a Single Crystal Nickel-Based Superalloy Containing Re/Ru at 1100°C/137MPa
Authors: Tian Su Gui , Wang Bao Shuai , Ding Xin , Shu De Long , Wu Jing
Published: April 2015

Creep behavior of a heat treated single crystal nickel base superalloy containing Re/Ru under the test condition of 1100°C/137MPa high temperatures was investigated. The experimental results showed that the segregation extent of elements in the dendrite and inter-dendrite regions of single crystal superalloy decreases by heat treatment at high temperature. The creep life of the alloy at 1100°C/137MPa was measured to be 321 h displaying a better creep resistance. Wherein, significant amount of fine cubiodal γ′ particles precipitated in the γ matrix channels are considered to be the main reason of the alloy having the better creep resistance. The deformation feature of the alloy during steady state creep is dislocations slipping in the γ matrix and climbing over the rafted γ′ phase. But in the latter stage of creep, the deformation feature of the alloy is dislocations shearing into the rafted γ′ phase. As creep goes on, the main / secondary slipping dislocations in the alloy are alternately activated to result in the initiation and propagation of the cracks along the interface of the rafted γ′/γ phase up to fracture, which is thought to be the fracture mechanism of the alloy during creep.
Effect of Hot Isostatic Pressing on the Microstructure of K417G Cast Turbine Discs
Authors: Li Jie , Yuan Chao , Guo Jian Ting , Hou Jie Shan , Zhou Lan Zhang
Published: April 2015

The present study focused on the effect of hot isostatic pressing (HIP) treatment on the microstructure of K417G superalloy. The experimental results showed that after the HIP treatment the size and volume fraction of the porosities significantly decreased. In addition, the dendritic structure and γ/γ' eutectics in the as-cast specimens became obscure after the HIP treatment due to the improvement of segregation. The γ′ phases in the dendrite core were smaller than those in the interdendritic region, whether in the as-cast or HIP specimens. The slow cooling at the end of the HIP treatment leads to the irregular morphology of the γ′ phases.
Interface Reaction between Ti3Al-based Alloy and Oxide Mold
Authors: Qian Luo
Published: April 2015

Ti3Al based alloys are light and high-temperature materials, having potential wide applications in the aerospace and the aeronautical industries. Molten Ti is lively, and it is easy to react with the mold material during in the investment casting, and hence to form casting defects such as α contaminated layer in the metal near the surface and gas porosity, resulting in the deterioration of the surface quality and castings mechanical properties. Therefore, the mechanism of interfacial reaction between Ti3Al-based alloys and mold is necessary to study. In this paper, the interface reaction samples of Ti-24Al-15Nb-1Mo alloy and ZrO2 (Y2O3 stabilized) mold were prepared by actually investment casting. Optical microscopy, SEM, EMPA and micro-hardness tests were used to study the microstructures at metal side of interface, consider the element distribution and discuss the interfacial reaction mechanism. The results show that there is interface reaction between Ti-24Al-15Nb-1Mo alloy and ZrO2 (Y2O3 stabilized) mold, and it belongs to the typical bilateral diffusion reaction. The elements of Zr, Y, O diffuse into molten metal, at the same time, the matrix elements spread to the oxide mold, then form interfacial reaction layer. It has been found that the interfacial reaction was not uniform in the whole interface. In the thick-wall of castings, the interfacial reaction layer was thicker, and in thin-wall, the interfacial reaction layer was thinner.
New-Type Co-Based Superalloys Designed by CALPHAD Method
Authors: Yang Shu Yu , Jiang Min , Wang Lei
Published: April 2015

The phase equilibria of new-type Co-based superalloys which include the system of Co-Al-W were studied by CALPHAD method. It was shown that γ+γ' two-phase regions were existed in the calculated phase diagrams. The compositions of new-type Co-based superalloys which can obtain γ+γ' microstructures were predicted due to the calculated phase diagram. The mole fractions of the constituent phases of Co-Al-W-Ni-Cr alloys were calculated. The temperature of γ' phase began to precipitate at about 1050°C.
Microstructure and Mechanical Properties of a New Ni-Cr-Fe-W-Al Alloy for Advanced Ultra-Supercritical Power Plants
Authors: Hao Xian Chao , Zhang Long , Zhao Xiu Juan , Liang Tian , Ma Ying Che , Liu Kui
Published: April 2015

Optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermodynamic calculation were used to study the phase stability and precipitation in a Ni-Cr-Fe-W-Al alloy. Mechanical properties were also studied. The major precipitates after standard heat treatment or prolonged aging at 725 oC and 800 oC were M23C6 and γ′. M23C6 precipitated intergranularly. P-phase was not detected after thermal exposure, which was different from the results of thermodynamic calculation. The average diameter of γ′ increased with the increasing exposure temperature and time, and could be depicted by the LSW theory. Specimens in solution-annealed condition exhibited excellent ductility. During the prolonged exposure at 725 oC, tensile strength and ductility at room and elevated temperatures kept well, which means this alloy possessed good microstructural stability after a long time exposure.
Effects of Co on the Solidification and Precipitation Behaviors of IN 718 Alloy
Authors: Xin Xin , Zhang Wei Hong , Yu Lian Xu , Liu Fang , Jia Dan , Sun Wen Ru , Hu Zhuang Qi
Published: April 2015

The effects of Co from 0 to 11.60 % (in mass fraction) on the solidification and precipitation behaviors of IN 718 alloy had been investigated. The results showed that the volume fraction of the dendrite core increased with the addition of Co. In the alloys with 0-5.84 %Co, the addition of Co could restrain the precipitation of blocky Laves phase and promoted the formation of eutectic Laves phase. In the alloys with 9.00-11.60 % Co, the eutectic gray phase and small blocky Laves phase precipitated in the interdendritic region. The eutectic gray phase increased and small blocky Laves phase decreased with increasing Co. The parallel lath-like δ-Ni3Nb phase was observed to precipitate in some interdendritic region without the formation of gray phase and Laves phase in the 9.00-11.60 % Co alloys. Further research found that Co slightly segregated in the dendrite core and markedly raised the solubility of element Mo in the dendrite core which resulted in reduced Mo in the residual liquid, and consequently, restrained Laves phase while promoted the precipitation of Mo-depleted gray phase and δ-Ni3Nb phase. Furthermore, Co was seemed to elevate the solidification point of the γ matrix while decrease that of the Laves phase.
Study of Isothermal Oxidation Behavior of FGH91 Superalloy
Authors: Peng Zi Chao , Ma Guo Jun , Wang Xu Qing , Luo Xue Jun
Published: April 2015

Oxidation behavior of FGH91 superalloy in air and the temperature range of 540 to 980 °C for period up to 100h has been studied. The results indicate that oxidation kinetics obeyed parabolic law, and the activation energy of oxidation was calculated to be 98.2 KJ/mol. The scales on the surface were determined by SEM, EDS and XRD, the results show that the oxidation scales were composed of three layers: the outer layer was composed of Cr2O3 layer with a small amount of TiO and NiCr2O4 spinel; the intermediate layer was made up of Al2O3 and matrix alloy; and a small amount of titanium-nitride disperse in the inner layer. Besides, γ’-free layer was formed under the oxidation scales due to the impoverishment of Al in this layer, which was induced by the formations of Al2O3.
Microstructure and Mechanical Properties of BN Nanotubes Reinforced Si3N4 Porous Composites
Authors: Liu Hai Kuan , Li Bin , Zhang Chang Rui , Wang Si Qing , Liu Kun
Published: April 2015

The high dielectric constant of Si3N4 ceramic limited its application as wave-transparent materials, thus Si3N4 ceramics always been prepared as porous ceramics to enhance the properties of wave transparent. While the mechanical properties would be declined in this way, so the BNNTs were used to improve the properties of the composites in this paper. The porous BNNTs/ Si3N4 composites were prepared by normal pressure sintering in nitrogen atmosphere. Then the effects of sintering temperature and contents of BNNTs to Si3N4 porous ceramics and composites were investigated. The results show that the Si3N4 phase was transformed to β-Si3N4 completely when the sintering temperature was raised to 1750°C. The BNNTs and rod-like β-Si3N4 guaranteed the considerable mechanical properties of the composites, and the mechanical properties increased with the increase of the sintering temperature and the addition of the BNNTs. When the sintering temperature was 1750°C and the content of BNNTs was 0.5wt.%, the porosity and density of the composite are 35% and 2.0g/cm3, respectively. While the flexural strength and the elastic modulus of the composite are 231.8MPa and 62.04GPa, respectively.
Microstructure Characteristics of TIG Welding Joint of 740H Pipe for Ultra-Supercritical Power Plant Boilers
Authors: Ye Jian Shui , Dong Jian Xin , Zhang Mai Cang , Yao Zhi Hao , Zheng Lei
Published: April 2015

Microstructure and mechanical property of tungsten inert gas (TIG) welding joint of 740H pipe were studied by optical microscope, scanning electron microscope and HV tester in this paper. The principal segregated elements in fusion zone of 740H weldment were Nb and Ti. The discontinuous MC-type phase with irregular shape and γ′ phase were distributed in the interdendritic region. The γ′, M23C6 and MC phases on grain boundary in heat affected zone (HAZ) dissolved into matrix. Hardness of weld metal and HAZ were apparantly lower than that of base metal. The previous weld bead was the heat affected zone of the subsequent weld metal, thus hardness was different in different area of the fusion zone (FZ). After the postweld heat treatment of 800°C/4h followed by air cooling, the volume fraction of γ′ in the interdendritic region was larger than that in the dendrite arm. The hardness of HAZ and FZ were approximately equal to that of base metal (BM).
Study on Preparation of LiNi0.5Co0.2Mn0.3O2 Precursor-Spherical Ni0.5Co0.2Mn0.3O2(OH)2
Authors: Qu Xiao Long , Zhang Zheng Fu , Cheng Jin , Wang Xiao Yan
Published: April 2015

The spherical Ni0.5Co0.2Mn0.3(OH)2 powders were prepared by ammonia-hydroxide co-precipitation method. The influence of different synthesizing factors on the precursors characteristic were investigated. The product prepared with optimized condition has tap density of D≥1.7g·cm-3, and middle particle size D50≈3.6μm. The X-ray diffraction (XRD) results showed that the precursor can be indexed by a hexagonal β-Ni (OH)2 structure. The scanning electron microscope (SEM) results showed that the powders had quasi-spherical pattern and homogeneous particle size distribution.
Preparation and Characterization of Amorphous Al-Based Metal Foams
Authors: Li Cong Bo , Chen Wei Wei , Wang Lu
Published: April 2015

Amorphous Al-Cu-Ti metal foams with the porosity of 65% were prepared by spark plasma sintering with both the diameter and height of 10 mm. The SPS process was carried out under the pressure, the dwell time and the temperatures of 300 MPa, 5min and 623-673K, respectively. The microstructure and mechanical behavior of the amorphous Al-Cu-Ti metal foams were investigated. The results showed that sintering at high temperatures improved the crystallinity and adhesion between particles. The intermetallic compounds, i.e. Al-Ti, Al-Cu and Al-Cu-Ti were identified from the XRD patterns. It was found that weak adhesion and irregular shape of NaCl might reduce the mechanical properties. The highest strength of amorphous Al-based metal foam sintered at 653K, 300MPa was 7.97MPa.
Effects of Co Element on Microstructure and Magnetic Properties of Fe-6.5wt%Si Magnetic Powder Cores
Authors: Liu Xin , Le Chen , Mao Xin Hua , Xie Huan Wen , Cai Yi Cang
Published: April 2015

Fe100-xCox-6.5wt%Si (x=0, 1, 3, 5, 7, 10, 15, 35, 50) magnetic powder cores (MPCs) were prepared by gas atomization,insulation, compression molding, and heat treatment. The effects of Co element on microstructure and magnetic properties of the Fe-6.5wt%Si MPCs were investigated. The results showed that the addition of Co element doesn’t change the phase structure of Fe-6.5wt%Si alloy powders. The saturation magnetization of the powders decreased after the first increase with the increase of the Co content, reaching the maximumfor Fe90Co10-6.5wt%Sipowder sample.The saturation magnetization of the MPCs decreased after the first increase with the increase of the Co content, reaching the maximumfor Fe93Co7-6.5wt%Si sample.The effective permeability of the MPCsdecreased after the first increase with the increase of the Co content, reaching the maximum for Fe95Co5-6.5wt%SiMPCs. The core loss of the MPCsincreased after the first decrease with the increase of the Co content, reaching the minimumfor Fe97Co3-6.5wt%SiMPCs. A small amount of Co element can improve effectively the whole magnetic properties of the Fe-6.5wt%Si MPCs.
Effect of HA Content on Microstructure and Compression Properties of Ti-Nb-Sn/HA Composites Fabricated by Plasma Current Activated Sintering
Authors: Wang Xiao Peng , Chen Yu Yong , Kong Fan Tao , Xiao Shu Long
Published: April 2015

Novel bio-composites were synthesized by plasma current activated sintering from the Ti-35Nb-2.5Sn/HA powders ball-milled for 12 h. The aim of this study was to investigate the effects of HA content (5, 10 and 15 wt%) on sintering properties, microstructure and compression properties of Ti-35Nb-2.5Sn/HA bio-composites. Results indicated that sintering rate decreased slightly with the increase of HA content. The phases of sintered composites were mainly˰ڂ˽̤̹˼˰̘̑˼˰Ca3(PO4)2(TCP), TiO2, CaTiO3 and TixPy. The grain size of sintered composites reduced with the increasing of HA content, and sintered composites with ultra fine grains were fabricated finally. The compression test showed that all the sintered composites had low elastic modulus and high compression strength. The elastic modulus of Ti-35Nb-2.5Sn/15HA sintered composites was 22GPa with a high strength of 877MPa.
Effect of Infiltration Temperature on the Composition and Mechanical Property of RMI C/C-SiC Composite
Authors: Wang Jing , Cao Ying Bin , Lin Dong , Liu Rong Jun , Zhang Chang Rui
Published: April 2015

C/C-SiC composites were prepared by reactive melt infiltration process at different temperatures. The composition, microstructures and mechanical properties of the composites were investigated. The results showed that infiltration temperature could affect composite’s properties through regulating the chemical composition and interfacial bonding strength of the composites. The C/C-SiC composite prepared at 1650°C exhibited the relatively highest performance with density of 2.24 g·cm-3 and SiC content of 31.44 vol.%. The flexural strength and the fracture toughness were 238MPa and 10.04 MPa·m1/2, respectively.
Double Inhibitory Actions on WC Grains of Microwave Sintered WC-12wt%Co-VC Alloy
Authors: Bao Rui , Yi Jian Hong , Zhang Jia Min , Liu Yi Chun , Li Feng Xian , Xin You , Tan Song Lin
Published: April 2015

It is well known that grain-refinement has a positive impact on the mechanical properties of WC-Co cemented carbide. The effect of VC inhibitor and microwave on density, microstructure and mechanical properties of the sintered WC–12wt%Co alloy was investigated in the present study. The ball milled WC-12wt%Co-xVC composites were compressed and fabricated by using microwave sintering method. The experimental results indicate that the microwave sintering cycle was significantly shorter to that of vacuum processing, and the density of bulk alloys increased with VC inhibitor contents and microwave sintering temperatures. Moreover, the microstructure observation of the sintered samples suggests that VC inhibitor had prominent inhibitory action on WC grains in microwave exposure, and the WC average grain size of alloy with 0.7wt%VC inhibitor was 0.43μm when the sintering temperature reached 1420°C. It is also evident that WC-12wt% alloys with an appropriate proportion of VC inhibitor exhibited higher hardness (92.1HRA) and better transverse rupture strength (2380MPa). And finally the mechanism of inhibitory effects on WC grains under microwave irradiation was discussed.
Microstructure and Mechanical Properties of X70 Pipeline Steel with High H2S Resistance
Authors: Li Jing , Gao Xiu Hua , Lu Yong , Du Lin Xiu
Published: April 2015

Anti-H2S X70 pipeline steel was developed. The microstructure of X70 pipeline steel was studied by the analysis of OM, SEM and TEM. The precipitation behavior was discussed. The comprehensive mechanical properties, HIC and SCC performance were systematically studied. The results indicated that the microstructure of the experimental steel was mainly acicular ferrite and granular bainite. The second phase precipitates dispersedly distributed in the matrix. The experimental steel possessed excellent strength, plasticity, low temperature toughness and low yield ratio. And therefore, the X70 pipeline steel in the study is suitable for sour service with the high strength, excellent toughness and low HIC&SSC susceptibility.
Thermodynamics of Amorphous Silicon Oxides in Sub-Rapid Solidified Low Carbon Steel
Authors: Zhao Dan , Cheng Jie Yun , Chen Jing , Li Hui Gai , Zheng Shao Bo
Published: April 2015

Strip casting technology leads a new revolutionary change for steel industry, which solidification rate could be 100-1000 K/s. The study on the size and structure of deoxidation products from the sub-rapid solidification will be of great significant in promoting the mechanical properties of the strip continuous casting steels. In the paper, the silicon oxide inclusions precipitated in sub-rapid solidified low carbon steel were investigated by transmission electron microscopy. The experimental results indicated that a large number of spherical silicon oxides were dispersed as amorphous state, and the size range was in hundreds nanometers. According to the thermodynamic calculation and inference, the silicon oxides would precipitate during the sub-rapid solidification of low carbon steel. SiO2, which structure is as approximate “liquid” and the melting temperature has been reduced under nanoeffect, has been frozen in amorphous state under high solidification rate. Amorphous SiO2 precipitated in steel may be due to the structural relaxation caused by high viscosity. The larger average size of amorphous SiO2 was detected at higher solidification rate, which is attributed to the cause to the higher hardening rate.
Influence of Duplex Annealing on the Microstructure and Mechanical Properties of Ti62421S Titanium Alloy Plate
Authors: Song Xiao Yun , Wang Yong Ling , Zhang Wen Jing , Hui Song Xiao , Ye Wen Jun
Published: April 2015

The effects of different duplex annealing treatments on the microstructure and mechanical properties of Ti62421S alloy plate were studied by optical microscope (OM), scanning electron microscope (SEM), electron probe microanalysis (EPMA) and tensile tests, The experimental results indicated that the original microstructure of Ti62421S was composed of primary α phase (αp) and intergranular β phase. With the increase of first-stage annealing temperature, the volume fraction of equiaxed αp phase decreased. In contrast, the content of transformed β structure (βt) increased, and the width of lamellar secondary α phase (αs) in βt increased. Consequently, the yield strength (σ0.2) and ultimate tensile strength (σb) at room temperature and 600°C increased, while the elongation (δ5) declined. After 1000°C/2h/AC+ 600°C/2h/AC duplex annealing treatment, Ti62421S alloy plate showed superior tensile properties. The values of σb and δ5 at room temperature reached 1133MPa and 6%, as well as the value of σb at 600°C exceeded 710MPa.
Effect of Sample Size upon Quasi-Static Compressive Loading of Ti48Zr20Cu5Nb12Be15 Amorphous Composites
Authors: Shen Yong Hua , Cheng Huan Wu , Xue Yun Fei , Wang Lu , Chen Wen Jia , Wang Ben Peng , Liu Huan , Zhu Chen Ke
Published: April 2015

In-suit β-Ti (Zr,Nb) dendrite/amorphous matrix composites were prepared by copper injection casting, specimens (1.5:1 aspect ratio) with different diameters were tested under quasi-static compressive loading at different strain rate. The results show that the structure of amorphous composites is amorphous matrix and in-suit β dendritic crystal phase; for 3mm and 4mm specimens, with the change of strain rate, the compressive strength and the fracture strain have no obvious changes. however, positive strain rate sensitivity was observed to 5mm specimens; in the same strain rate, with the decrease of the diameters, compressive strength and fracture strain all have great increases, which indicate the amorphous composites has obvious size effect.
Standards for Resuscitation After Cardiac Surgery
Authors: Ley S. Jill
Published: April 2015

Of the 250 000 patients who undergo major cardiac operations in the United States annually, 0.7% to 2.9% will experience a postoperative cardiac arrest. Although Advanced Cardiac Life Support (ACLS) is the standard approach to management of cardiac arrest in the United States, it has significant limitations in these patients. The European Resuscitation Council (ERC) has endorsed a new guideline specific to resuscitation after cardiac surgery that advises important, evidence-based deviations from ACLS and is under consideration in the United States. The ACLS and ERC recommendations for resuscitation of these patients are contrasted on the basis of the essential components of care. Key to this approach is the rapid elimination of reversible causes of arrest, followed by either defibrillation or pacing (as appropriate) before external cardiac compressions that can damage the sternotomy, cautious use of epinephrine owing to potential rebound hypertension, and prompt resternotomy (within 5 minutes) to promote optimal cerebral perfusion with internal massage, if prior interventions are unsuccessful. These techniques are relatively simple, reproducible, and easily mastered in Cardiac Surgical Unit–Advanced Life Support courses. Resuscitation of patients after heart surgery presents a unique opportunity to achieve high survival rates with key modifications to ACLS that warrant adoption in the United States.
Nurse-Physician Collaboration and Hospital-Acquired Infections in Critical Care
Authors: Boev Christine , Xia Yinglin
Published: April 2015

Background

Nurse-physician collaboration may be related to outcomes in health care–associated infections. OBJECTIVE To examine the relationship between nurse-physician collaboration and health care–associated infections in critically ill adults.

Methods

A secondary analysis was done of 5 years of nurses’ perception data from 671 surveys from 4 intensive care units. Ventilator-associated pneumonia and central catheter–associated bloodstream infections were examined. Multilevel modeling was used to examine relationships between nurse-physician collaboration and the 2 infections.

Results

Nurse-physician collaboration was significantly related to both infections. For every 0.5 unit increase in collaboration, the rate of the bloodstream infections decreased by 2.98 (P= .005) and that of pneumonia by 1.13 (P= .005). Intensive care units with a higher proportion of certified nurses were associated with a 0.43 lower incidence of bloodstream infections (P= .02) and a 0.17 lower rate of the pneumonia (P= .01). With nursing hours per patient day as a covariate, units with more nursing hours per patient day were associated with a 0.42 decrease in the rate of bloodstream infections (P= .05).

Conclusion

Nurse-physician collaboration was significantly related to health care–associated infections.
Coordinated Expression of DNAM-1 and LFA-1 in Educated NK Cells
Authors: Enqvist Monika , Ask Eivind Heggernes , Forslund Elin , Carlsten Mattias , Abrahamsen Greger , Béziat Vivien , Andersson Sandra , Schaffer Marie , Spurkland Anne , Bryceson Yenan , Önfelt Björn , Malmberg Karl-Johan
Published: April 2015

The functional capacity of NK cells is dynamically tuned by integrated signals from inhibitory and activating cell surface receptors in a process termed NK cell education. However, the understanding of the cellular and molecular mechanisms behind this functional tuning is limited. In this study, we show that the expression of the adhesion molecule and activation receptor DNAX accessory molecule 1 (DNAM-1) correlates with the quantity and quality of the inhibitory input by HLA class I–specific killer cell Ig-like receptors and CD94/NKG2A as well as with the magnitude of functional responses. Upon target cell recognition, the conformational state of LFA-1 changed in educated NK cells, associated with rapid colocalization of both active LFA-1 and DNAM-1 at the immune synapse. Thus, the coordinated expression of LFA-1 and DNAM-1 is a central component of NK cell education and provides a potential mechanism for controlling cytotoxicity by functionally mature NK cells.
IL-10 Critically Modulates B Cell Responsiveness in Rankl−/− Mice
Authors: Marrella Veronica , Lo Iacono Nadia , Fontana Elena , Sobacchi Cristina , Sic Heiko , Schena Francesca , Sereni Lucia , Castiello Maria Carmina , Poliani Pietro Luigi , Vezzoni Paolo , Cassani Barbara , Traggiai Elisabetta , Villa Anna
Published: April 2015

The immune and the skeletal system are tightly interconnected, and B lymphocytes are uniquely endowed with osteo-interactive properties. In this context, receptor activator of NF-κB (RANK) ligand (RANKL) plays a pivotal role in lymphoid tissue formation and bone homeostasis. Although murine models lacking RANK or RANKL show defects in B cell number, the role of the RANKL–RANK axis on B physiology is still a matter of debate. In this study, we have characterized in detail B cell compartment in Rankl−/− mice, finding a relative expansion of marginal zone B cells, B1 cells, and plasma cells associated with increased Ig serum levels, spontaneous germinal center formation, and hyperresponse to CD40 triggering. Such abnormalities were associated with an increased frequency of regulatory B cells and augmented B cell–derived IL-10 production. Remarkably, in vivo IL-10-R blockade reduced T cell–triggered plasma cell differentiation and restrained the expansion of regulatory B cells. These data point to a novel role of the RANKL–RANK axis in the regulation of B cell homeostasis and highlight an unexpected link between IL-10 CD40 signaling and the RANKL pathway.
Newly Recruited CD11b+, GR-1+, Ly6Chigh Myeloid Cells Augment Tumor-Associated Immunosuppression Immediately following the Therapeutic Administration of Oncolytic Reovirus
Authors: Clements Derek R. , Sterea Andra M. , Kim Youra , Helson Erin , Dean Cheryl A. , Nunokawa Anna , Coyle Krysta Mila , Sharif Tanveer , Marcato Paola , Gujar Shashi A. , Lee Patrick W. K.
Published: April 2015

Tumor-associated immunosuppression aids cancer cells to escape immune-mediated attack and subsequent elimination. Recently, however, many oncolytic viruses, including reovirus, have been reported to overturn such immunosuppression and promote the development of a clinically desired antitumor immunity, which is known to promote favorable patient outcomes. Contrary to this existing paradigm, in this article we demonstrate that reovirus augments tumor-associated immunosuppression immediately following its therapeutic administration. Our data show that reovirus induces preferential differentiation of highly suppressive CD11b+, Gr-1+, Ly6Chigh myeloid cells from bone marrow hematopoietic progenitor cells. Furthermore, reovirus administration in tumor-bearing hosts drives time-dependent recruitment of CD11b+, Gr-1+, Ly6Chigh myeloid cells in the tumor milieu, which is further supported by virus-induced increased expression of numerous immune factors involved in myeloid-derived suppressor cell survival and trafficking. Most importantly, CD11b+, Gr-1+, Ly6Chigh myeloid cells specifically potentiate the suppression of T cell proliferation and are associated with the absence of IFN-γ response in the tumor microenvironment early during oncotherapy. Considering that the qualitative traits of a specific antitumor immunity are largely dictated by the immunological events that precede its development, our findings are of critical importance and must be considered while devising complementary interventions aimed at promoting the optimum efficacy of oncolytic virus–based anticancer immunotherapies.
SNX17 Affects T Cell Activation by Regulating TCR and Integrin Recycling
Authors: Osborne Douglas G. , Piotrowski Joshua T. , Dick Christopher J. , Zhang Jin-San , Billadeau Daniel D.
Published: April 2015

A key component in T cell activation is the endosomal recycling of receptors to the cell surface, thereby allowing continual integration of signaling and Ag recognition. One protein potentially involved in TCR transport is sorting nexin 17 (SNX17). SNX proteins have been found to bind proteins involved in T cell activation, but specifically the role of SNX17 in receptor recycling and T cell activation is unknown. Using immunofluorescence, we find that SNX17 colocalizes with TCR and localizes to the immune synapse in T– conjugates. Significantly, knockdown of the SNX17 resulted in fewer T–APC conjugates, lower CD69, TCR, and LFA-1 surface expression, as well as lower overall TCR recycling compared with control T cells. Lastly, we identified the 4.1/ezrin/radixin/moesin domain of SNX17 as being responsible in the binding and trafficking of TCR and LFA-1 to the cell surface. These data suggest that SNX17 plays a role in the maintenance of normal surface levels of activating receptors and integrins to permit optimum T cell activation at the immune synapse.
Epigenetic Downregulation of SFRP4 Contributes to Epidermal Hyperplasia in Psoriasis
Authors: Bai Jing , Liu Zhaoyuan , Xu Zhenyao , Ke Fang , Zhang Lingyun , Zhu Huiyuan , Lou Fangzhou , Wang Hong , Fei Ye , Shi Yu-Ling , Wang Honglin
Published: April 2015

Psoriasis is a chronic recurrent inflammatory skin disorder characterized by the dysregulated cross-talk between epidermal keratinocytes and immune cells, leading to keratinocyte hyperproliferation. Several studies demonstrated that Wnt pathway genes were differentially expressed in psoriatic plaques and likely were involved in the pathophysiology of disease. However, the molecular mechanisms underlying Wnt signaling regulation in epidermal hyperplasia in psoriasis remain largely unknown. We report that the expression of secreted frizzled-related protein (SFRP) 4, a negative regulator of the Wnt signaling pathway, was diminished in lesional skin of mouse models and patients with psoriasis. SFRP4 directly inhibited excessive keratinocyte proliferation evoked by proinflammatory cytokines in vitro. Pharmacological inhibition of Wnt signaling or intradermal injection of SFRP4 decreased the severity of the psoriasiform skin phenotype in vivo, including decreased acanthosis and reduced leukocyte infiltration. Mechanistically, we identified that aberrant promoter methylation resulted in epigenetic downregulation of SFRP4 in inflamed skin of patients with psoriasis and in the IL-23–induced mouse model. Our findings suggest that this epigenetic event is critically involved in the pathogenesis of psoriasis, and the downregulation of SFRP4 by CpG island methylation is one possible mechanism contributing to the hyperplasia of epidermis in the disease.
A Unique Mouse Strain That Develops Spontaneous, Iodine-Accelerated, Pathogenic Antibodies to the Human Thyrotrophin Receptor
Authors: Rapoport Basil , Aliesky Holly A. , Banuelos Bianca , Chen Chun-Rong , McLachlan Sandra M.
Published: April 2015

Abs that stimulate the thyrotropin receptor (TSHR), the cause of Graves’ hyperthyroidism, only develop in humans. TSHR Abs can be induced in mice by immunization, but studying pathogenesis and therapeutic intervention requires a model without immunization. Spontaneous, iodine-accelerated, thyroid autoimmunity develops in NOD.H2h4 mice associated with thyroglobulin and thyroid-peroxidase, but not TSHR, Abs. We hypothesized that transferring the human TSHR A-subunit to NOD.H2h4 mice would result in loss of tolerance to this protein. BALB/c human TSHR A-subunit mice were bred to NOD.H2h4 mice, and transgenic offspring were repeatedly backcrossed to NOD.H2h4 mice. All offspring developed Abs to thyroglobulin and thyroid-peroxidase. However, only TSHR-transgenic NOD.H2h4 mice (TSHR/NOD.H2h4) developed pathogenic TSHR Abs as detected using clinical Graves’ disease assays. As in humans, TSHR/NOD.H2h4 female mice were more prone than male mice to developing pathogenic TSHR Abs. Fortunately, in view of the confounding effect of excess thyroid hormone on immune responses, spontaneously arising pathogenic human TSHR Abs cross-react poorly with the mouse TSHR and do not cause thyrotoxicosis. In summary, the TSHR/NOD.H2h4 mouse strain develops spontaneous, iodine-accelerated, pathogenic TSHR Abs in female mice, providing a unique model to investigate disease pathogenesis and test novel TSHR Ag-specific immunotherapies aimed at curing Graves’ disease in humans.
Evaluation of right ventricular function performed by 3d-echocardiography in scleroderma patients
Authors: Pigatto E. , Peluso D. , Zanatta E. , Polito P. , Miatton P. , Bourji K. , Badano L. P. , Punzi L. , Cozzi F.
Published: April 2015

The impairment of the right ventricle (RV) in systemic sclerosis (SSc) is usually related to pulmonary arterial hypertension (PAH). New echocardiographic techniques, such as 3-dimensional echocardiography (3DE) and 2-dimensional speckle tracking (2DSTE), allow an accurate evaluation of the RV function. The aim of this study was to evaluate the RV function using 3DE and 2DSTE in SSc patients with no history of heart disease and no PAH. Forty-five SSc patients, 42 females and 3 males, 28 with limited cutaneous SSc (lcSSc) and 17 with diffuse cutaneous SSc (dcSSc), were studied. Forty-three age- and gender-matched healthy subjects were enrolled as controls. All of them underwent a 3DE and 2DSTE ecocardiographic evaluation of the RV function. Systolic pulmonary arterial pressure (sPAP) and total pulmonary vascular resistance (tPVR) were also estimated by power doppler. RV echocardiographic parameters were compared in the different subsets of SSc patients. A statistical analysis was performed by t-test, ANOVA and multiple logistic regression. RV areas in 2DSTE and volumes in 3DE were higher and RV function parameters were reduced in SSc patients compared with controls. Also sPAP and tVPR were higher, but they did not reach pathological values. Echocardiographic alterations were more pronounced in patients with lcSSc. 3DE and 2DSTE echocardiography allowed us to detect morphological and functional alterations of the RV in a group of SSc patients with no clinical signs of heart disease and no PAH. These patients had significantly higher sPAP and tPVR than healthy controls without reporting values compatible with PAH. These data suggest that RV alterations are related to a pressure overload rather than to an intrinsic myocardial involvement in SSc.
Change perspective to increase diagnostic accuracy of ultrasonography in calcium pyrophosphate dihydrate deposition disease! A new approach: the axial scan of the meniscus
Authors: Filippou G. , Picerno V. , Adinolfi A. , Di Sabatino V. , Bertoldi I. , Galeazzi M. , Frediani B.
Published: April 2015

Ultrasonography (US) is a relevant tool in the study of calcium pyrophosphate dihydrate (CPP) deposition disease. However, differential diagnosis of hyperechoic deposits within the fibrocartilage can be difficult; moreover, US study is limited by the need of an adequate acoustic window. We describe a US scanning technique that offers a new viewpoint in the study of knee meniscal structure: a longitudinal scan performed according to the long axis of meniscus. This technique proves to be particularly useful for the identification of CPP deposition, but could also improve the US diagnostic utility and accuracy in other meniscal pathologies.
Comparative Outcome of Computed Tomography-guided Percutaneous Radiofrequency Ablation, Partial Nephrectomy or Radical Nephrectomy in the Treatment of Stage T1 Renal Cell Carcinoma
Authors: Cooper Chad J. , Teleb Mohamed , Dwivedi Alok , Rangel Gabriela , Sanchez Luis A. , Laks Shaked , Akle Nassim , Nahleh Zeina
Published: April 2015

Renal cell carcinoma (RCC) accounts for 3% of all cancers in adults. The indications for Radiofrequency Ablation (RFA) for renal carcinomas include T1a (tumor 4 cm or less, limited to the kidney), elderly patients, renal impairment, comorbidities, poor surgical candidate, and multiple bilateral renal masses. We retrospectively reviewed medical records, specifically investigating the indications, complications and outcomes of RFA and nephrectomy for treatment of RCC in a tertiary medical center with a predominantly Hispanic patient population. Forty-nine patients with RCC were evaluated. Nine patients had RFA, 9 had partial nephrectomy and 31 had radical nephrectomy. All patients among the 3 groups had stage T1N0M0 RCC at diagnosis. Tumor recurrence was observed in 2 (22%) patients that had RFA, one (11%) patient that had partial nephrectomy and no patients that had radical nephrectomy. One patient had recurrence of the tumor at the opposite kidney pole from the initial RFA site 4 years later. This particular patient did not have any tumor recurrence at the site of the initial RFA. A second RFA was performed on the recurrent tumor with no recurrence upon subsequent follow up visits. The second patient had recurrence of the RCC on 1 year follow that was discovered to be sarcomatoid RCC, which is an aggressive type with a poor prognosis. Our results support the clinical utility of RFA in patients with stage T1 RCC who are poor surgical candidates or those with reduced renal function. The clinical utility of RFA as an equally effective approach when compared to partial nephrectomy in patients with stage T1 RCC that meet strict indications for the procedure. The treatment choice should be individualized and based on the characteristics of the renal tumor such as size, location and histological type of RCC. We conclude that RFA presents a safe treatment choice for patients with RCC if long term follow up is maintained.
Paraneoplastic Autoimmune Hemolytic Anemia in Ovarian Cancer: A Marker of Disease Activity
Authors: Loh Kah Poh , Kansagra Ankit , Asik Armen , Ali Syed , Dahiya Saurabh
Published: April 2015

Autoimmune hemolytic anemia (AIHA) is a rare paraneoplastic syndrome associated with ovarian malignancies. We report a case of a 77 year-old female with metastatic ovarian carcinoma who presented with worsening anemia from her baseline, and was found to have a warm autoimmune hemolytic anemia. We performed a literature review and analyzed all 10 cases (including our patient) that have been reported to date, and incorporated the clinical presentation, histology and stage of underlying malignancies, types, treatment, prognosis and mechanisms of AIHA in ovarian carcinoma.
Retroperitoneal Schwannomas of Renal and Pararenal Origin: Presentation of Two Case Reports
Authors: Herden Jan , Drebber Uta , Ural Yasemin , Zimmer Sandra , Wille Sebastian , Engelmann Udo H.
Published: April 2015

Retroperitoneal schwannomas are a rare entity. They originate from the Schwann cells of the nerve sheaths and may be of renal or pararenal origin. We report on two patients with retroperitoneal schwannomas, who received surgery under the suspicion of renal cell carcinoma.
Giant Cells Glioblastoma: Case Report and Pathological Analysis from this Uncommon Subtype of Glioma
Authors: Belsuzarri Telmo A.B. , Araujo João F.M. , Catanoce Aguinaldo P. , Neves Maick W.F. , Sola Rodrigo A.S. , Navarro Juliano N. , Brito Leandro G. , Silva Nilton R. , Pontelli Luis Otavio C. , Mattos Luiz Gustavo A. , Gonçales Tiago F. , Zeviani Wolnei M. , Marques Renata M.B.
Published: April 2015

Glioblastoma multiforme (GBM) is the most common glial tumor of the brain system; nevertheless, the giant cell (GC) subtype is uncommon. Recent reviews report for an incidence of 1% in adults and 3% in children. The GCs usually have a better prognosis than GBM and also an increasing long-term survival rate. It is known that the diagnosis of this tumor is due to its histological findings and patterns, such as the unusual increased number of giant cells. Unfortunately, due to its rarity, the immunohistochemical and cytogenetical analysis of this tumor is not well known. Some authors also suggest that there are few subtypes of GCs and their patterns of aggressiveness could be due to cytogenetical markers. It is recognized that maximum safe resection treatment and adjuvant radiotherapy can improve survival rate (5-13 months) similar to GBM patients.
Soft Tissue Sarcomas of the Kidney
Authors: Köhle Olivia , Abt Dominik , Rothermundt Christian , Öhlschlegel Christian , Brugnolaro Christiane , Schmid Hans-Peter
Published: April 2015

Soft tissue sarcomas are rare mesenchymal tumors. Amongst others, primitive neuroectodermal tumors (PNET) of the kidney and synovial sarcoma of the kidney belong to the group of soft tissue sarcomas. Synovial sarcomas can occur almost anywhere in the body, most frequently, however, in the lower (62%) or upper extremities (21%). Metastases occur in 50-70% of cases, and thus the prognosis is poor. PNETs are rare, highly aggressive neoplastic lesions which mainly occur in the torso or axial skeleton in young adults. The prognosis is poor with a 5-year disease-free survival rate of 45-55%. The primary therapeutic approach is surgical resection. Most randomized studies assessing adjuvant chemotherapy for all types of localized soft tissue sarcomas did not show statistically significantly better overall survival times after chemotherapy, although they did show longer progression-free survival. We report on two cases of primary renal synovial sarcoma and one case of PNET of the kidney.
Cherubism in Sub-Saharan Africa: A First Case-Report in a Child
Authors: Aloni Michel Ntetani , Kambere Renault Sitwaminya , Molua Antoine , Dilu Joseph Nzinga , Tshibassu Pierre Manianga , Kazadi-Lukusa Aimé , Ngiyulu René Makuala , Kalengayi Raphael Mbona , Ehungu Jean Lambert Gini
Published: April 2015

Cherubism is rare disease and has been rarely reported in African pediatric population. We report here the case of a 10-year-old child who was referred to our hospital for bilateral jaws swelling. Physical examination revealed bilateral swelling symmetry of the face. Histopathological examination of the biopsy specimen showed loose fibrous stroma, proliferating fibrous connective with tissue interspersed with multinucleated giant cells, small thin walled blood vessels and scattered sparse mononuclear inflammatory infiltrate. Our patient presented cherubism. Cherubism is rarely described in children living in sub-Saharan Africa. Genetic and molecular investigations plays an important role in diagnosis but were not available in poor resources settings in developing countries such as the Democratic Republic of Congo.
Primary Gastric Hemangioblastoma: Report of a Case
Authors: Basave Horacio N. López , Morales-Vasquez Flavia , Monterrubio Juan Carlos Tenorio , Gomez Angel Herrera , Molina Juan Manuel Ruiz , Esquivel Gonzalo Montalvo , Lino-Silva Leonardo Saúl
Published: April 2015

Capillary hemangioblastoma (CHB) is a benign, highly vascularized tumor that generally occurs in central nervous system either in the setting of von Hippel-Lindau (VHL) disease or, more often, as a solitary sporadic lesion that is increasingly recognized in extraneural sites. We present the case of a 18 year-old man with abdominal pain, nausea and hematemesis, the endoscopy showed polypoid tumor bleeding of 5 cm in gastric antrum. The patients had not signs of VHL disease and was subjected to subtotal gastrectomy and referred to our institution. To our knowledge this is the first reported case of CHB occurring in stomach.
Primary Gastric Melanoma: Case Report of a Rare Malignancy
Authors: Augustyn Alexander , de Leon Emma Diaz , Yopp Adam C.
Published: April 2015

We report the case of a 64-year-old white male who presented to his primary care physician with complaints of fatigue. Physical exam was unremarkable and laboratory studies revealed profound anemia, for which the patient received a transfusion. Esophagogastroduodenoscopy revealed a bleeding mass in the proximal stomach that was histologically determined to be malignant melanoma, with immunohistochemical staining demonstrating positivity for SOX10, S100, MART-1, and HMG-45. After an extensive dermatological exam no other primary lesion was identified. Whole body positron emission tomography (18-FDG-PET/CT) demonstrated pathologic uptake only in the area of the proximal stomach. For this reason, primary gastric melanoma was suspected in this patient. The patient underwent subtotal gastrectomy with mass excision followed by Roux-en-Y reconstruction. Very few cases of primary gastric melanoma have been reported. We report this case and present diagnostic criteria for primary non-cutaneous melanoma and discuss potential non-surgical therapies.
Seasonal tropospheric oscillations observed in InSAR time series
Authors: Samsonov S V , Trishchenko A , Tiampo K
F , González P J , Fernández J , Zhang Y
Published: April 2015

Applying the Multidimensional Small Baseline Subset Interferometric Synthetic Aperture Radar (MSBAS InSAR) algorithm to 250 ENVISAT and RADARSAT-2 SAR images spanning 2003-2013 we computed time series of ground deformation over Naples Bay Area in Italy. Two
active volcanoes, Vesuvius and Campi Flegrei, are located in this area in close proximity to a densely populated city of Naples. For the first time with a remarkable clarity in the vertical component of time series we observed elevation dependent seasonal oscillations with an amplitude of up to 1.5
cm, substantially larger than the longterm annual deformation rate. Analysis, utilizing ground weather station and radiosonde data, linked observed oscillations with seasonal fluctuations of water vapor, air pressure and temperature in a lower troposphere. Atmospherically corrected time series
confirmed continuing subsidence at Vesuvius previously observed by GPS and levelling techniques. Developed methodology demonstrated that for spatially localized studies the Atmospheric Path Delay (APD) can be successfully modeled as an elevation dependent seasonally oscillating
signal.