bluuebunny/crossref_metadata_2025 huggingface dataset:
Coalescent species delimitation of a Sumatran parachuting frog
Authors: O'Connell Kyle A , Smith Eric N , Shaney Kyle J , Arifin Umilaela , Kurniawan Nia , Sidik Irvan , Fujita Matthew K
Published: December 2017

We conduct species delimitation of the widespread parachuting frog species Rhacophorus catamitus using samples from across the island of Sumatra, Indonesia. We use mitochondrial, genomic and morphological data, and find that R. catamitus is composed of three lineages corresponding to northern, central and southern lineages. Mitochondrial and genomic data show admixture or incomplete lineage sorting between the central and southern lineages, but deep divergence from the northern lineage. Coalescent species delimitation supports a three species model for this complex, and we recommend that the northern lineage be described as a new species. Our study highlights the power of coalescent species delimitation in an integrative framework for identifying unrecognised diversity in understudied tropical species complexes. We also emphasise the evolutionary importance of northern Sumatra, a region that harboured montane refugia during Pliocene–Pleistocene climate change, but has also been heavily affected by volcanic activity.
Restoration of metabolic health by decreased consumption of branched‐chain amino acids
Authors: Cummings Nicole E. , Williams Elizabeth M. , Kasza Ildiko , Konon Elizabeth N. , Schaid Michael D. , Schmidt Brian A. , Poudel Chetan , Sherman Dawn S. , Yu Deyang , Arriola Apelo Sebastian I. , Cottrell Sara E. , Geiger Gabriella , Barnes Macy E. , Wisinski Jaclyn A. , Fenske Rachel J. , Matkowskyj Kristina A. , Kimple Michelle E. , Alexander Caroline M. , Merrins Matthew J. , Lamming Dudley W.
Published: December 2017

Key points

We recently found that feeding healthy mice a diet with reduced levels of branched-chain amino acids (BCAAs), which are associated with insulin resistance in both humans and rodents, modestly improves glucose tolerance and slows fat mass gain.

In the present study, we show that a reduced BCAA diet promotes rapid fat mass loss without calorie restriction in obese mice.

Selective reduction of dietary BCAAs also restores glucose tolerance and insulin sensitivity to obese mice, even as they continue to consume a high‐fat, high‐sugar diet.

A low BCAA diet transiently induces FGF21 (fibroblast growth factor 21) and increases energy expenditure.

We suggest that dietary protein quality (i.e. the precise macronutrient composition of dietary protein) may impact the effectiveness of weight loss diets.

Obesity and diabetes are increasing problems around the world, and although even moderate weight loss can improve metabolic health, reduced calorie diets are notoriously difficult to sustain. Branched‐chain amino acids (BCAAs; leucine, isoleucine and valine) are elevated in the blood of obese, insulin‐resistant humans and rodents. We recently demonstrated that specifically reducing dietary levels of BCAAs has beneficial effects on the metabolic health of young, growing mice, improving glucose tolerance and modestly slowing fat mass gain. In the present study, we examine the hypothesis that reducing dietary BCAAs will promote weight loss, reduce adiposity, and improve blood glucose control in diet‐induced obese mice with pre‐existing metabolic syndrome. We find that specifically reducing dietary BCAAs rapidly reverses diet‐induced obesity and improves glucoregulatory control in diet‐induced obese mice. Most dramatically, mice eating an otherwise unhealthy high‐calorie, high‐sugar Western diet with reduced levels of BCAAs lost weight and fat mass rapidly until regaining a normal weight. Importantly, this normalization of weight was mediated not by caloric restriction or increased activity, but by increased energy expenditure, and was accompanied by a transient induction of the energy balance regulating hormone FGF21 (fibroblast growth factor 21). Consumption of a Western diet reduced in BCAAs was also accompanied by a dramatic improvement in glucose tolerance and insulin resistance. Our results link dietary BCAAs with the regulation of metabolic health and energy balance in obese animals, and suggest that specifically reducing dietary BCAAs may represent a highly translatable option for the treatment of obesity and insulin resistance.
Microstructure Stability of Alloy 740H and its Effect on Material Properties
Authors: de Barbadillo John J. , Baker Brian A. , Xie Xishan
Published: December 2017

Alloy 740H was developed specifically for boiler tube and steam transfer pipe for the Advanced-Ultrasupercritical steam boiler application. The composition was formulated to provide creep strength, weldability and oxidation and coal ash corrosion resistance. It is the first nickel-base age-hardened alloy to be approved under Section 1 of the ASME Boiler and Pressure Vessel Code. Although a significant amount of microstructure and creep data was submitted to support the code case, it was largely collected on tube and light plate, much of this from pilot-scale material. The data package did not cover other product forms, sizes, hot working methods and weld joint configurations that may be required to construct a power plant. These include large diameter pipe, bends, fittings, heavy section welds, dissimilar metal welds, etc. that have complex thermal cycles and composition gradients. An ongoing effort is underway to characterize the microstructure and properties of alloy 740H under a range of manufacturing processes and to project these results through the potential life cycle of a plant. This paper describes the current status of this work.

Paper published with permission.
Microstructural Stability of Alloy 617 Mod. During Thermal Aging
Authors: Yan Guo , Rongcan Zhou , Liying Tang , Shufang Hou , Bohan Wang
Published: December 2017

The microstructural stability of Alloy 617 mod. during aging for up to 3000 h at temperatures of 700°C and 750°C was investigated. The precipitates of the aged alloy included M23C6 carbides located both inside grains (intragranular) and at grain boundaries (intergranular) and γ′ phase dispersed within grains. During aging, the intergranular precipitates showed a good stability. Intragranular particles increased substantially after the aging for 3000h at 750°C. Inter and intragranular carbide particles resulted in the precipitation hardening of the aged alloys. The precipitation of γ′ phase particles during aging at 700°C and 750°C is also an important factor for an enhanced hardness and an obvious decrease of the impact absorbed energy. Additionally, the intergranular cracks apparently lead to a decrease in the impact absorbed energy for the aged alloys due to carbide particles at grain boundaries. The impact absorbed energies of the aged alloys were fairly stable within the dwelling time from 300 h to 3000 h and were in the range of 63∼65J and 75∼83J for the 700°C and 750°C aging, respectively.

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Biaxial Thermal Creep of Alloy 617 and Alloy 230 for VHTR Applications
Authors: Mo Kun , Lv Wei , Tung Hsiao-Ming , Yun Di , Miao Yinbin , Stubbins James F.
Published: December 2017

In this study, we employed pressurized creep tubes to investigate the biaxial thermal creep behavior of Inconel 617 (Alloy 617) and Haynes 230 (Alloy 230). Both alloys have been considered to be the primary candidate structural materials for very high temperature reactors (VHTRs) due to their exceptional high-temperature mechanical properties. The current creep experiments were conducted at 900°C for the effective stress range of 15–35 MPa. For both alloys, complete creep strain development with primary, secondary, and tertiary regimes were observed in all studied conditions. The tertiary creep was found to be dominant in the entire creep lives of both alloys. With increasing applied creep stress, the fraction of the secondary creep regime decreases. The nucleation, diffusion, and coarsening of creep voids and carbides on grain boundaries was found to be the main reason for the limited secondary regime, and was also found to be the major cause of creep fracture. The creep curves computed using the adjusted creep equation of the form ε = Aσ cosh−1(1 + rt) + Pσntm agree well with the experimental results for both alloys at the temperatures of 850–950°C.

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Alloy Design of Creep- and Oxidation-Resistant 9Cr-Boron Steel Beyond Grades 91, 92 and 122
Authors: Abe Fujio , Tabuchi Masaaki , Tsukamoto Susumu , Kutsumi Hiroyuki
Published: December 2017

The addition of boron and nitrogen without the formation of any boron nitrides during normalizing heat treatment at high temperature improves long-term creep strength and rupture ductility of base metal and suppresses Type IV fracture in welded joints of 9Cr ferritic power plant steel at 650°C. The enrichment of soluble boron near prior austenite grain boundaries (PAGBs) by the segregation is essential for the stabilization of fine distribution of M23C6 carbides along boundaries in the vicinity of PAGBs, enhancing the boundary and subboundary hardening. 9Cr-3W-3Co-VNb steel (MARBN) with 120–150 ppm boron and 60–90 ppm nitrogen, in which no boron nitride formed during normalizing, exhibits not only much higher creep strength and rupture ductility of base metal than Gr.92 but also substantially no degradation in creep strength due to Type IV fracture in welded joints at 650°C. The formation of protective Cr2O3-rich oxide scale is achieved on the surface of MARBN by pre-oxidation treatment in argon gas, which significantly improves the oxidation resistance in steam. The present results suggest that MARBN is superior to Gr.91, Gr.92, and Gr.122 in terms of creep strength of base metal and welded joints and can be applied to boiler components in next-generation USC power plant.

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Prediction of Long-Term Creep Rupture Life of Grade 122 Steel by Multi-Region Analysis
Authors: Maruyama K. , Nakamura J. , Yoshimi K.
Published: December 2017

Conventional time-temperature-parameter (TTP) methods often overestimate long-term rupture life of creep strength enhanced ferritic steels. Decrease in activation energy Q for rupture life in long-term creep is the cause of the overestimation, since the TTP methods cannot deal with the change in Q. Creep rupture data of a heat of Gr.122 steel (up to 26200h) were divided into several data sets so that Q was unique in each divided data set. Then a TTP method was applied to each divided data set for rupture life prediction. This is the procedure of multi-region analysis of creep rupture data. The predicted rupture lives have been reported in literature. Long-term rupture lives (up to 51400h) of the same heat of the steel have been published in 2013. The multi-region analysis of creep rupture life can predict properly the long-term lives reported. Stress and temperature dependences of rupture life show similar behavior among different heats. Therefore, database on results of the multi-region analyses of various heats of the steel is helpful for rupture life estimation of another heat.

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New Ferritic Steel Beyond Grade 92 and its Creep Degradation Assessment by Hardness Method for Grade 91
Authors: Masuyama Fujimitsu , Yamaguchi Tomiko
Published: December 2017

The alloy development R&D activities for weld construction components, such as boiler piping and headers of high-efficient fossil-fired power plants have been conducted to introduce creep strength enhanced ferritic (CSEF) steels, grades 91, 92, 122, 911, 23 and 24 for last three decades. The grade 92 among these CSEF steels has the highest creep rupture strength to increase the steam temperature up to 620°C however the weld heat affected zone is much weaker in creep than the base metal due to the Type IV failure. Alloy design trials or proposal of the candidate steels in laboratory level has been conducted to improve the creep rupture strength than that of grade 92. Presently it is becoming possible in a very near future to introduce the new high strength ferritic steels beyond grade 92 on the commercial basis, and also the new steels could mitigate the Type IV failure at the welds to be applicable at the maximum use temperature of 625°C and above. But the creep degradation behavior in such new advanced steels is not yet well investigated and it is not verified that the creep degradation/life assessment techniques studied for the existing CSEF steels are applicable. Therefore the creep degradation and softening behavior of new advanced CSEF steels were studied and the hardness creep life assessment technique developed using grade 91 was applied to investigate the similarity of degradation process with the conventional CSEF steels. The present paper introduces the development status of new advanced steels beyond grade 92 in Japan and deals with the creep degradation and softening behavior of the new steels in comparison with grades 91 and 92.

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A Combined Experimental-Computational Approach to Design Optimization of High Temperature Alloys
Authors: Jha Rajesh , Dulikravich George S. , Pettersson Frank , Saxén Henrik , Chakraborti Nirupam
Published: December 2017

Experimental data were used to develop metamodels to predict high temperature alloy chemistry trends influencing stress-to-rupture and time-to-rupture of Nickel based superalloys. Chemistry optimization utilized evolutionary neural networks, bi-objective genetic programming and pruning algorithm. Optimization results were compared with the experimental data and IOSO optimization algorithm. Response surfaces were developed through various modules available in a commercial optimization package. Pareto optimized chemistries were tested using thermodynamic database, FactSage™, by studying the phase distribution as a function of temperature of manufacture and exposure. Uniformity in the amount of critical phases over 0–1200 °C range confirmed high temperature stability for optimized alloys.

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Improvement of Creep Performance of Creep Strength Enhanced Ferritic (CSEF) Steel Weldments Through Non-Standard Heat Treatments
Authors: Yamamoto Yukinori , Yu Xinghua , Babu Sudarsanam Suresh
Published: December 2017

Significant improvement of creep-rupture life was observed in Grade 91 (modified 9Cr-1Mo) steel weldments when a non-standard heat-treatment was applied prior to welding. A lower temperature pre-weld tempering (LTT) than the typical heat-treatment resulted in a complete dissolution of M23C6 carbides in the fine-grained heat affected zone (FGHAZ) during welding, which allowed re-precipitation of the M23C6 as strengthening carbides after post-weld heat treatment. However, the LTT also raised the ductile-brittle transition temperature of the base metal above room temperature. A thermo-mechanical treatment (TMT) has been proposed in the present study as a way of balancing the need for improved creep properties in the weld region and an acceptable level of room temperature ductility in the base metal. Aus-forging and subsequent aus-aging promotes MX formation prior to martensitic transformation which effectively increases the creep resistance, even in the FGHAZ. The application of the standard tempering after the TMT process improves the room temperature ductility without losing the advantage of improved strength. Preliminary results indicate a successful improvement of the cross-weld creep properties of the TMT sample similar to the LTT sample.

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A Method to Evaluate the Temper Embrittlement From Step Cooling Test
Authors: Hankui Wang , Tong Xu , Binan Shou
Published: December 2017

A new mathematic approach is proposed to evaluate the temper embrittlement from the step cooling test. The approach is composed of two parts. A nonlinear model, which acts as weight factor, is used to fit the variance at different test temperatures, and the maximum likelihood method is used to determine the curve parameters. In the ASME specification SA-542, there is no instruction provided on how to determine the transition temperature from the test results. This method could be adopted as an additional supplementary requirement to assess the temper embrittlement of Chromium-Molybdenum steel.

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The Microstructure Stability of the 10Cr9MoW2VNbBN Heat Resistant Steel
Authors: Baolan Gu , Binan Shou , Tong Xu , Zhiying Wu
Published: December 2017

In this paper, the microstructure of 9%Cr steel 10Cr9MoW2VNbBN under different heat treatment or creep testing was investigated. The morphology of tempered martensite microstructure varies after different heat treatment. After the creep test at 620°C or 650°C, the martensite lath microstructure kept unchanged, although the amounts and the sizes of precipitates, such as the carbides M23C6, carbonitrides MX, and Laves phase, increased with the creep time. The martensite laths microstructure morphology changed after the creep test at 700°C, with the carbides coarsened severely at grain boundaries.

Paper published with permission.
High Temperature Constitutive Model Development for Alloy 617
Authors: Quayyum Shahriar , Pritchard Patrick Graham , Hassan Tasnim
Published: December 2017

One of the most challenging tasks in the design code development for Next Generation Nuclear Plant (NGNP) is the design of intermediate heat exchanger (IHX), whose operation temperature may range from 800°C–950°C (1472°F–1742°F). The ASME design code does not have any design provisions for any material at this temperature range. Hence, different candidate materials are under consideration for IHX and one of the leading candidate materials is Ni based Alloy 617. The operating temperature of IHX will be in the creep regime of Alloy 617 and low-cycle creep-fatigue and creep-ratcheting failure mechanisms of Alloy 617 need to be understood. This study is developing a unified constitutive model (UCM) for Alloy 617 based on a broad set of uniaxial and multiaxial creep-fatigue and creep-ratcheting experiments at high temperatures. The experiments were conducted at different temperatures, loading rates and strain ranges prescribing different loading histories. The unified constitutive model was developed based on the Chaboche viscoplastic model framework. Model improvement was performed by including cyclic hardening/softening, dynamic and static recovery, strain rate and strain range dependence, nonproportional loading parameter and multiaxial ratcheting features. The simulated responses of the modified UCM were compared against the broad range of experimental data to demonstrate the robustness of the improved model. The strengths and shortcomings of the model are discussed.

Paper published with permission.
The Application of Elevated Temperature Materials for USC Boilers in China
Authors: Xu Tong , Shou Binan , Wang Hankui , Sun Chao
Published: December 2017

In this paper, the history of elevated temperature material production in China was reviewed, and the application status of elevated temperature materials for USC boilers in China was introduced. A comparison of Chinese standard GB5310 and ASME relevant codes of elevated temperature material designations was also proposed. Finally, statistical analysis of chemical compositions and mechanical properties of some domestic and imported material productions, including T/P91 and T/P92, was presented.

Paper published with permission.
Evaluation of Limit Load Analysis Methods Applied to High Temperature Design: Part 1 — Consistent Material Modeling
Authors: Dewees Dave , Jain Rahul
Published: December 2017

Design-by-Rule codes (i.e. ASME Section I, EN 12952) already exist for elevated temperature (creep) design and have been successfully used for decades; however, there is motivation to optimize designs, or to assess non-standard ones. Limit Load Analysis (LLA) is the simplest advanced analysis method, and a powerful and widely-used tool for establishing compliance with required pressure part safety margins for operation at temperatures below the creep range. However, there is no direct relationship between LLA and elevated temperature allowable stresses and failure modes, such that the basic LLA methods or results must be manipulated in some way to be generally meaningful. With this in mind, review of proposed elevated temperature LLA methods (which are discussed in Part 2 of this work) by comparison to detailed transient inelastic finite element analysis allows for rigorous assessment of simplifications. Specification of an elevated temperature material model that is consistent with traditional allowable stresses for the detailed analysis is described in this paper (Part 1), and the material model and simplified methods are applied to the case of a typical steam header in the next (Part 2).

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A Study for Evaluating Local Damage to RC Panels Subjected to Oblique Impact: Part 1 — A Study for Evaluating Local Damage Caused by Oblique Impact of Rigid Projectiles
Authors: Ohta Yoshimi , Nishida Akemi , Tsubota Haruji , Li Yinsheng
Published: December 2017

Many empirical formulae have been proposed to evaluate the local damage to reinforced concrete structures caused by the impact of rigid projectiles. Most of these formulae have been derived based on impact tests perpendicular to the target structures. To date, few impact tests oblique to the target structures have been conducted. The purpose of this study is to propose a new formula for evaluating the local damage caused by oblique impacts based on experiments and simulations. The new formula is derived by modifying an empirical formulation for normal impact and the agreement with results of past oblique impact tests is discussed.
A Study for Evaluating Local Damage to Reinforced Concrete Panels Subjected to Oblique Impact: Part 3 — Simulation Analysis for Evaluating Perforation Phenomena Caused by Oblique Impact of Deformable Projectiles
Authors: Tsubota Haruji , Ohta Yoshimi , Nishida Akemi , Li Yinsheng
Published: December 2017

The purpose of this study is to propose a new formula for evaluating the local damage to reinforced concrete structures caused by oblique impact based on past experimental results and simulation results. In this paper, we present the results of simulation analyses for evaluating the perforation of concrete panels due to oblique impact by deformable projectiles. Various response characteristics and perforation mechanisms such as detailed perforation behavior, damage to reinforced concrete panels, rupture states of the deformable projectiles, reduction in projectile velocity, and residual velocity of the projectile after perforation, and energy transfer processes are clarified. Especially, it is found that the sliding energy consumed by friction occurring at the contact surface between a projectile and a reinforced concrete panel due to oblique impact is remarkably larger than that due to normal impact.
Research on the Fracture Mechanics Analysis Method for Reactor Pressure Vessel Nozzle Corner Flaw
Authors: Rui Shen , Ming Cao , Yinbiao He , Hongxin Tao
Published: December 2017

This paper has discussed the stress intensity factor solution method of most popular used nuclear equipment design code and published papers. A series of inlet and outlet nozzle of reactor pressure vessel 3-D FEA fracture mechanics models with different size of corner flaw are created by ABQUAS software. Moreover, the crack front has been specially processed by ZENRCAK software. By compare the stress intensity factor solutions of FEA method and the solutions of influence function method for a 1/4 infinite symmetry plate, the influence functions for PWR reactor pressure vessel inlet and outlet nozzle corner flaw solution are obtained.
Nuclear Island Basemat Modeling for Generation III Nuclear Power Plant Design in China
Authors: Shang Ziduan , Wu Chunhua , Han Boyu , Chang Chenyu , Zhang Lutong
Published: December 2017

Nuclear Island (NI) basemat is a very thick reinforced concrete mat sitting on sub-grade soil to function as one-piece-foundation to support all super-structures anchored above the basemat. The Generation III (GEN III) NI is designed with more structures housing on the basemat, as such it is even greater in dimensions compared to GEN II. In the design process of a GEN III Passive-Safety-Plant (PSP), NI base mat is the most critical part for foundation design, since it is not only serves as the pressure boundary in foundation system but also support the whole nuclear island, carrying vertical load from upper structures, seismic loads both in vertical and horizontal directions, lateral soil pressures and buoyant force due to water table etc. For a typical AP plant the main structural systems which are housing within NI comprises of steel containment vessel (SCV), shield building (SC wall), internal structures, and auxiliary buildings etc. The scope for this paper is to investigate the approach and method which are suitable for modeling GEN III passive-safety-plant basemat. The investigation scopes are focused on (1) concrete basemat FE modeling and related subgrade medium (soil) modeling; (2) Design loads evaluation method and application for a typical basemat FE static analysis. Structurally speaking SCV is designed to directly anchored in concrete basemat, the interface between upper structure and foundation, its geometry and connection are unique and complicated, this lead to the modeling of basemat not only have to consider an appropriate FE meshing and element type selection but also need to consider the load application and transferring from the SCV to the basemat basin.

Since passive-safety-plant NI basemat is a deep foundation, basemat is deeply buried below the grade, the complete foundation model not only shall consider the basemat and immediate soil under the basemat, but also need to consider the backfill soil, the surrounding soil in vicinity, fill concrete under the basemat and deeper soil condition under the basemat. Since seismic loads pose great effects on basemat and its foundation design, how to evaluation seismic loadings and simplified their application for basemat static analysis is critical for such type of foundation.
Researches on the Test of Web Local Failure Modes and Related FEA Study
Authors: Xiao Wenyu , Liang Bingbing
Published: December 2017

In the analysis of structure steel beam member of mechanical module and piping support in nuclear power plant, beam web shall be analyzed complying with the ASME III NF requirements against web local failure including web local yielding, web local crippling, web sideway buckling and web compression buckling when the beam is subjected to concentrated loads. Referring to the H Type steel structure beam of China GB code; this paper researches the tests of carrying capacity related to the above mentioned local failure mechanism. The results could show that the evaluation method of web local failure mechanism in ASME III NF cover the China GB code steel structure member on one hand; And on the other hand, the results could show the rationalities of the sectional dimension design of the member and the rationality of the beam span. And based on the analysis of the test results, reasonable suggestions could made for the above mentioned member dimension design and beam span design.
Qualification of Ultrasonic Examination for RPV Nozzle to Shell Welds of EPR Nuclear Power Plant
Authors: Wang WeiQiang , Yu Zhe , Ye Xin , Chen HuaiDong , Ma GuanBing
Published: December 2017

European Pressurized Reactor (EPR) nuclear power plant is now under construction in China. One of the biggest changes in the EPR reactor pressure vessel (RPV) is the nozzle to shell welds are designed as “set-on” principle instead of “set-in” principle in the CPR1000 units. The nozzle to shell welds of the EPR pressure vessel must be inspected according to the RSE-M code. This is necessary in order to guarantee the integrity of the primary circuit. The In-Service Inspection (ISI) program of EPR nuclear power plant demands the automatic ultrasonic inspection of the nozzle to shell welds from nozzle inner surface. This paper presents the technical characteristics of the EPR reactor vessel, and analyzes the in-service examination requirements of nozzle to shell welds. Technical solutions have been designed to perform the examination of the component. The qualification process of the ultrasonic examination of the nozzle to shell welds is also presented.
Research on the Shaking Table Test Model of PCS Storage Tank of AP1000 Nuclear Power Engineering
Authors: Xiong Jie
Published: December 2017

Since the responses of Liquid storage tanks (LST) include the liquid motion, structural motion, and fluid-structure interaction (FSI) under the earthquake ground motion, it is a difficult problem about shaking table test model for satisfying similarity ratio requirement. The two experimental models, namely satisfied FSI similarity ratio model (FSI model) and unsatisfied FSI similarity ratio (un-FSI) model, respectively, are presented in this paper. The PCS storage tank of AP1000 Nuclear Power Engineering, as the study project, is studied by Adina software, and the responses, such as stress, stain, and displacement, etc., of prototype model, FSI model, and un-FSI model are compared. The results provide that when researchers study the rigidity LST dynamic response parameters and vibration characteristics, such as displacement, acceleration and liquid wave height, the tank wall stress response parameters etc., FSI model should be used.
Development of Analysis Method for Impact and Splash Behavior of Water-Filled Tank
Authors: Takazawa Hidekazu , Hirosaka Kazuma , Miyazaki Katsumasa , Tohyama Norihide , Matsumoto Naomi
Published: December 2017

A new Japanese nuclear regulation requirement prepares estimating the possible damage to plant structures due to acts of terrorism, such as intentional aircraft impact. Aircraft impact needs to be considered in existing nuclear power plants. The structural damage and fuel splash behavior after aircraft impact into plant structures can be estimated using finite element analysis (FEA). FEA needs validated experimental data to determine the reliability of results.

In this study, an analysis method was validated using a simple model such as a cylindrical tank. Numerical simulations were conducted to estimate the impact and splash behavior for a water-filled cylindrical tank. The simulated results were compared with the test results of the VTT Technical Research Centre of Finland. Simulations were carried out using a multipurpose FEA code LS-DYNA®. The cylindrical tank was modeled using a shell element, and filled water was modeled using a smoothed particle hydrodynamics (SPH) element. First, two analysis models were used to estimate the effect of the number of SPH elements. One was generated with about 300,000 SPH elements. The other was generated with 37,000 SPH elements. The cylindrical tank ruptured in the longitudinal direction after impact into a rigid wall, and the filled water splashed. Few differences emerged in the simulated results using different numbers of SPH elements. The impact test of the VTT was simulated with an arbitrary Lagrangian-Eulerian (ALE) element to consider the air drag. The analytical splash pattern and history of splash velocity ratio agreed well with the impact test results.
Correlation between Contrast-Enhanced Ultrasound and Microvessel Density via CD31 and CD34 in a rabbit VX2 lung peripheral tumor model
Authors: Xing Jin , He Wen , Ding Yi-Wen , Li Yang , Li Yan-Dong
Published: December 2017

Aim: To evaluate the tumor angiogenesis in lung peripheral VX2 tumor model by contrast-enhanced ultrasound (CEUS) and to determine the correlation between CEUS parameters and microvessel density (MVD) calculated via CD31 and CD34 expression.Material and methods: VX2 pulmonary tumors were created in eight Japanese white rabbits by implanting a VX2 sarcoma into the lower portion of the right lung through ultrasound guidance. Tumors were allowed to grow for 14-21 days to achieve a diameter of 7-15 mm, and were examined by CEUS using a SonoVue contrast agent. The results were recorded as digital video images, and the time-intensity curves and hemodynamic parameters were analyzed. Pathological tumor specimens were immediately obtained after the ultrasound examinations. Tumor specimens were stained with hematoxylin and eosin (H&E) and expressed as CD31 and CD34. The different endothelial cell markers were determined by immunohistochemical staining. MVD was calculated via CD 31 and CD34, and the relationship between CEUS parameters and MVD was analyzed.Results: Two distinct types of microvessels were identified in lung peripheral VX2 tumors: differentiated (CD34+) and undifferentiated (CD31+) vessels. A significant correlation was found between CEUS parameters and undifferentiated MVD (CD31+ vessels) in lung peripheral VX2 tumors (p<0.05). A reverse correlation was observed between different MVDs.Conclusions: Two different degrees of differentiation of vascular endothelial cells (CD31 and CD34) exist in the rabbit lung peripheral VX2 tumor model. CD31 MVD can more effectively evaluate tumor angiogenesis compared with CD34 MVD. CEUS, as a non-invasive imaging method, can effectively evaluate tumor angiogenesis in rabbit peripheral lung cancer.
Greyscale and contrast enhanced ultrasonography for characterization of gastric malignant tumors
Authors: Neciu Cristian Vasile , Puia Ion Cosmin , Badea Alexandru Florin , Socaciu Mihai , Botan Emil , Chiorean Ioana , Opincariu Iulian , Iancu Cornel , Badea Radu
Published: December 2017

Aims: To evaluate the utility of grey scale ultrasonography (US) and contrast enhanced ultrasonography (CEUS) for characterization of malignant gastric tumors.Material and methods: The study was conducted prospectively and it included a number of 30 patients with malignant gastric tumors diagnosed through upper tract endoscopy and biopsy: 25 adenocarcinomas, 3 lymphomas, and 2 stromal tumors. All the patients were examined by US, followed immediately by CEUS, using both oral and intravenous contrast agents. CEUS assessed the dynamics of the contrast agent during the arterial phase and the venous phase. The distribution characteristics of the contrast agent inside the region of interest (ROI) were also evaluated. Twenty four patients underwent surgery.Results: Adenocarcinomas presented heterogeneous enhancement with variable pattern, followed by a delayed wash-out in almost all of the situations. Lymphomas presented a variable pattern, intensity and homogeneity of the enhancement, followed by delayed wash-out. Stromal tumors showed early arterial intense and homogenous enhancement followed by moderate wash-out in venous phase.Conclusions: Grey scale US and CEUS are useful methods in characterizing gastric tumors and contribute to a more adequate evaluation of the lesions. The dynamics of the contrast agent may be suggestive for the anatomopathological nature of the tumor. Larger studies will be necessary in order to determine thepractical value of the method.
A new larval species of Balaustium (Acari: Erythraeidae) from northern Iran and Turkey with a key to the genera of larval Balaustiinae and species of Balaustium
Authors: Noei Javad , Asadollahzadeh Solmaz , Cakmak Ibrahim , Hadizadeh Alireza
Published: December 2017

Balaustium akramii Noei sp. nov. is described and illustrated from forest soils in Sari city, Mazandaran province, Iran and from building walls and windows edges in Aydin, Turkey. A key to genera of the subfamily Balaustiinae and a key to species of Balaustium of the world (larva) are provided.
Optical properties of borosilicate glass from 3.1 mm to 210 nm (0.4 meV to 5.89 eV) by spectroscopic ellipsometry
Authors: Uprety Prakash , Junda Maxwell M. , Podraza Nikolas J.
Published: December 2017

Borosilicate glass is of significant interest and utility to for a variety of applications, often for its robust ability to withstand significant thermal stresses resulting from a low coefficient of thermal expansion. Here, ellipsometric spectra of borosilicate glass from the millimeter wavelength range (terahertz) to the ultraviolet are collected from rotating compensator configuration ellipsometers. Specifically, spectra from three instruments each measuring a separate spectral range (0.4–4.1 meV; 0.035–0.75 eV; 0.75–5.89 eV) are modeled simultaneously. Continuous parameterization of the complex dielectric function (ε = ε1 + iε2) spectra from 0.4 meV to 5.89 eV describing the optical response of the glass is determined by modeling the measured spectra. Additionally, intensity-based transmittance measurement spanning 0.75–5.89 eV is used to determine the absorption coefficient at photon energies greater than 4 eV. Phonon absorption features are identified at low energies in the infrared and terahertz ranges.
Enhancing acoustic signal response and absorption of an underwater coated plate by embedding periodical inhomogeneities
Authors: Zhang Yanni , Pan Jie
Published: December 2017

An underwater structure is proposed for simultaneous detection and stealth purposes by embedding periodic signal conditioning plates (SCPs) at the interface of two elastic coatings attached to an elastic plate. Results show that the embedded SCPs can enhance sound absorption at frequencies below the coincidence frequency of the plate (fc). Significantly enhanced absorption occurs at five peaks, of which the peak due to excited localized bending resonance in the outer coating between SCPs is the most significant. When the dilatational velocity of the outer coating equals that of the inner coating, nearly total absorption occurs in a wideband, owing to strong coupling between the localized waveguide resonance in the outer coating and that in the inner coating, and the diffraction waves by the SCPs. Meanwhile, an amplified acoustic signal of over 14 dB is observed at most frequencies within 0 ∼ fc at the coatings' interface close to the SCPs' edges, owing to focused stress formed there. Peaks in the signal response at maximal 30 dB are also observed. These peak frequencies are coincident with or close to the peak frequencies of absorption, demonstrating that significantly enhanced acoustic signal and absorption can be achieved simultaneously through the use of embedded periodic SCPs.
Synergistic action of the MCL-1 inhibitor S63845 with current therapies in preclinical models of triple-negative and HER2-amplified breast cancer
Authors: Merino Delphine , Whittle James R. , Vaillant François , Serrano Antonin , Gong Jia-Nan , Giner Goknur , Maragno Ana Leticia , Chanrion Maïa , Schneider Emilie , Pal Bhupinder , Li Xiang , Dewson Grant , Gräsel Julius , Liu Kevin , Lalaoui Najoua , Segal David , Herold Marco J. , Huang David C. S. , Smyth Gordon K. , Geneste Olivier , Lessene Guillaume , Visvader Jane E. , Lindeman Geoffrey J.
Published: December 2017

The MCL-1 inhibitor S63845 is effective in combination with conventional therapy for targeting triple-negative and HER2-amplified breast cancer.
Statins are skin safe, now go innovate!
Authors: Lev-Tov Hadar
Published: December 2017

Epidemiological data demonstrate no overall increased risk of skin cancer with statin use.
New clues from Earth’s most elusive impact crater: Evidence of reidite in Australasian tektites from Thailand
Authors: Cavosie Aaron J. , Timms Nicholas E. , Erickson Timmons M. , Koeberl Christian
Published: December 2017

Australasian tektites are enigmatic drops of siliceous impact melt found in an ∼8000 × ∼13,000 km strewn field over Southeast Asia and Australia, including sites in both the Indian and Pacific oceans. These tektites formed only 790,000 yr ago from an impact crater estimated to be 40–100 km in diameter; yet remarkably, the young and presumably large structure remains undiscovered. Here we report new evidence of a rare high-pressure phase in Australasian tektites that further constrains the location of the source crater. The former presence of reidite, a high-pressure polymorph of zircon, was detected in granular zircon grains within Muong Nong–type tektites from Thailand. The zircon grains are surrounded by tektite glass and are composed of micrometer-sized neoblasts that contain inclusions of ZrO2. Each grain consists of neoblasts in three distinct crystallographic orientations as measured by electron backscatter diffraction, where all [001] directions are orthogonal and aligned with one <110> direction from the other two orientations. The systematic orientation relationships among zircon neoblasts are a hallmark of the high-pressure polymorphic transformation to reidite and subsequent reversion to zircon. The preserved microstructures and dissociation of zircon to ZrO2 and SiO2 require a pressure >30 GPa and a temperature >1673 °C, which represent the most extreme conditions thus far reported for Australasian Muong Nong–type tektites. The data presented here place further constraints on the distribution of high-pressure phases in Australasian tektites, including coesite and now reidite, to an area centered over Southeast Asia, which appears to be the most likely location of the source crater.
Latest Neoproterozoic to Cambrian detrital zircon facies of western Laurentia
Authors: Matthews William , Guest Bernard , Madronich Lauren
Published: December 2017

Late Neoproterozoic to Cambrian sandstone units are common in western Laurentia and record initial transgression of the craton after the formation of the western passive margin during the latest Neoproterozoic to earliest Cambrian. Detrital zircon measurements from 42 latest Neoproterozoic to Cambrian basal Sauk sequences and five older Neoproterozoic sandstone samples from a region extending from the Mexico–United States border to central British Columbia, Canada, are combined with previous results to characterize sediment source areas and dispersal systems. Detrital zircon populations in Neoproterozoic and Cambrian sedimentary rocks are divided into six facies based on a statistical comparison using multidimensional scaling. Detrital zircon facies are found in unique geographical regions reflecting proximity to the major tectonic provinces of Laurentia. Samples from northern regions are dominated by Archean and Paleoproterozoic zircons derived from Archean tectonic provinces and the orogenic belts that record the assembly of the Laurentian craton. More southerly sample locations show an increase in detrital zircons derived from younger Paleoproterozoic orogenic belts and early Mesoproterozoic intrusive suites. Detrital zircons from Grenville-aged sources are common in the south. The Transcontinental Arch, a feature interpreted to have controlled large-scale sediment dispersal patterns in the mid- to late Cambrian, likely played a major role in isolating the southern and northern signatures. Our data set can be used to test tectonic models for the Cordilleran orogen that invoke Jurassic or Cretaceous collision of a ribbon continent as the driving mechanism for orogenesis. Cambrian rocks of the Cassiar-Antler platform juxtaposed with North America during the hypothetical ribbon continent collision show the same geographic distribution of detrital zircon facies as similar-aged rocks from autochthonous and parautochthonous locations on the Laurentian margin. The concordance of detrital zircon facies across the proposed suture is a negative result for models that predict large dextral displacements, on the order of 2000 km, across the suture.
Men’s health and co-residence with older generations in Russia: better or worse?
Authors: Permyakova Natalia Vadimovna , Billingsley Sunnee
Published: December 2017

Background

Previous studies show contradictory findings on the relationship between health and intergenerational living arrangements (ILAs), which may be due to variation in who selects themselves into and out of ILA. Addressing the selectivity into ILA and the health of the older generation, we assess whether there is a health-protective or health-damaging effect of ILA. We locate our study in the Russian context, where ILA is prevalent and men’s health has become a public health issue.

Methods

We apply a fixed-effects logistic regression to self-rated health status of 11 546 men aged 25 years or older who participated in at least two waves in the Russian Longitudinal Monitoring Survey from 1994 to 2015. To further isolate the health effect of ILA, we observe only associations after transitioning into or out of ILA.

Results

A transition into co-residence with an unhealthy older generation increases men’s odds of reporting poor health (OR=0.64, CI 0.44 to 0.93). A transition out of co-residence with a healthy older generation decreases men’s odds of reporting fine health by 63% (OR=0.37, CI 0.28 to 0.50), whereas continuing to live with an unhealthy older generation decreases the odds by half (OR=0.49, CI 0.38 to 0.63).

Conclusions

We reveal a health interlinkage between co-residing generations by finding a detrimental health effect of co-residence with an unhealthy older generation. No longer living with an older generation who was in fine health also negatively affects men’s health. Future studies should address heterogeneity related to the health of older generations, unobserved time-constant characteristics of younger generations and selectivity into/out of ILA.
Hemodynamics and coil distribution with changing coil stiffness and length in intracranial aneurysms
Authors: Fujimura Soichiro , Takao Hiroyuki , Suzuki Takashi , Dahmani Chihebeddine , Ishibashi Toshihiro , Mamori Hiroya , Yamamoto Makoto , Murayama Yuichi
Published: December 2017

Purpose

The purpose of this study was to investigate hemodynamics and coil distribution with changing coil stiffness and length using the finite element method (FEM) and computational fluid dynamics (CFD) analysis.

Methods

Basic side-wall and bifurcation type aneurysm models were used. Six types of coil models were generated by changing the coil stiffness and length, based on commercially available embolic coils. Coil embolization was simulated using FEM. CFD was performed to characterize the hemodynamics in the aneurysms after embolization. Coil distribution and velocity reduction in the aneurysms were evaluated.

Results

The median value of radial coil distribution was shifted from the center to the outer side of the aneurysmal dome by changing coil stiffness: harder coils entered the outer side of the aneurysmal dome more easily. Short coils were more distributed at the neck region, since their small size made it easy for them to enter the tighter area. CFD results also indicated that velocity in the aneurysm was effectively reduced when the coils were more distributed at the neck region and the outer side of the aneurysmal dome because of the disturbance in blood inflow.

Conclusions

It is easier for coils to enter the outer side of the aneurysmal sphere when they are harder. If coils are short, they can enter tighter areas more easily. In addition, high coil density at the outer side of the aneurysmal dome and at the neck region is important to achieve effective velocity reduction.