bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gene–environment interactions at the FKBP5 locus: sensitive periods, mechanisms and pleiotropism
Authors: Zannas A. S. , Binder E. B. 
Published: November 2013

AbstractPsychiatric phenotypes are multifactorial and polygenic, resulting from the complex interplay of genes and environmental factors that act cumulatively throughout an organism's lifetime. Adverse life events are strong predictors of risk for a number of psychiatric disorders and a number of studies have focused on gene–environment interactions (GxEs) occurring at genetic loci involved in the stress response. Such a locus that has received increasing attention is the gene encoding FK506 binding protein 51 (FKBP5), a heat shock protein 90 cochaperone of the steroid receptor complex that among other functions regulates sensitivity of the glucocorticoid receptor. Interactions between FKBP5 gene variants and life stressors alter the risk not only for mood and anxiety disorders, but also for a number of other disease phenotypes. In this review, we will focus on molecular and system‐wide mechanisms of this GxE with the aim of establishing a framework that explains GxE interactions. We will also discuss how an understanding of the biological effects of this GxE may lead to novel therapeutic approaches.
Sensitivity of Two Quinoa (ChenopodiumquinoaWilld.) Varieties to Progressive Drought Stress
Authors: Sun Y. , Liu F. , Bendevis M. , Shabala S. , Jacobsen S.‐E. 
Published: November 2013

AbstractQuinoa (ChenopodiumquinoaWilld.) is a highly nutritious Andean seed crop which shows great potential to grow under a range of hostile environments. The objective of this study was to investigate the differences of drought tolerance of a Bolivian (Achachino) and a Danish (Titicaca) variety, and especially drought‐related adaption strategies. Soil water status was expressed as the fraction of transpirable soil water (FTSW). Relative stomatal conductance (RSC), relative transpiration (RT) and relative leaf water potential (RLW) were calculated by determining stomatal conductance, transpiration rate and leaf water potential of the drought‐treated plants relative to those of fully irrigated plants. The responses of RSC, RT and RLW to decreasing FTSW were described by a linear‐plateau model. The critical value of FTSW was the threshold of FTSW where the parameters studied decreased. The thresholds increased CS for stomatal conductance, CT for transpiration and CLfor leaf water potential. Achachino showed significantly lower CT and CL when compared with Titicaca, implying that transpiration and leaf water potential were less affected under mild drought conditions in the Bolivian variety. CS in Achachino was significantly higher than CL and CT, which indicated that stomatal conductance declined before transpiration and leaf water potential were reduced. Such difference was found in Titicaca where reduction of leaf area had more effect on transpiration than stomatal closure. Slower growth rate and smaller leaf area in combination with a lower stomatal conductance was found to contribute to drought resistance in Achachino. ABA concentration in the xylem sap tended to increase in both varieties after 2 days onset of drought, prior to decline in leaf water potential. Titicaca showed significantly (P < 0.05) higher ABA concentration when compared with Achachino under both fully irrigated and drought conditions. Titicaca had higher xylem nutrient concentration in comparison with Achachino in both fully‐watered and drought plants at day 2 after onset of soil drying. It was concluded that Titicaca was more sensitive to progressive drought than Achachino which avoided water loss by means of lower growth rate and smaller leaf area.
Comparative Analysis of mRNA Expression of Surface Antigens between Histiocytic and Nonhistiocytic Sarcoma in Dogs
Authors: Yamazaki H. , Takagi S. , Oh N. , Hoshino Y. , Hosoya K. , Okumura M. 
Published: November 2013

BackgroundDefinitive diagnosis of histiocytic sarcoma (HS) in dogs is relatively difficult by conventional histopathological examination because objective features of HS are not well defined.HypothesisQuantitative analysis of mRNA expression of selected cellular surface antigens (SAs) specific to HS in dogs can facilitate objective and rapid diagnosis.AnimalsDogs with HS (n = 30) and dogs without HS (n = 36), including those with other forms of lymphoma (n = 4), inflammatory diseases (n = 6), and other malignant neoplasias (n = 26).MethodsRetrospective clinical observational study. Specimens were collected by excisional biopsy, needle core biopsy, or fine needle aspiration. To determine HS detection efficacy, mRNA expression levels of selected SAs specific to HS in dogs, including MHC class IIα, CD11b, CD11c, and CD86, were quantitatively analyzed using real‐time quantitative polymerase chain reaction.ResultsEach SA mRNA expression level was significantly higher in HS dogs than in non‐HS dogs (P = .0082). Cutoff values for discriminating between HS and non‐HS dogs based on these expression levels were calculated on the basis of receiver‐operating characteristic analysis. Accuracy of the cutoff values, including MHC class IIα, CD11b, CD11c, and CD86, was 87.9, 86.4, 86.4, and 84.8%, respectively.Conclusions and Clinical ImportanceOur results suggest that quantitative analysis of mRNA expression of the selected SAs could be an adjunctive diagnostic technique with high diagnostic accuracy for HS in dogs. Substantial investigation is required for exclusion of diseases with similar cell types of origin to lymphoma.
Time to adequate oxygenation following ventilation using the Enk oxygen flow modulator versus a jet ventilator via needle cricothyrotomy in rabbits
Authors: Wong Carrie F. P. , Yuen Vivian M. , Wong Gordon T. C. , To Jensen , Irwin Michael G. 
Published: November 2013

SummaryIntroductionLimited information is available on the management of the ‘cannot intubate, cannot ventilate’ (CICV) situation in infants. We compared the time to achieve adequate oxygenation following rescue ventilation using the Enk oxygen flow modulator (OFM) with a jet ventilator in a simulated CICV situation using the rabbit as an infant respiratory model.MethodsFollowing institutional ethics committee approval, needle cricothyrotomy was performed under direct vision in nine anesthetized rabbits following surgical exposure of the larynx. After ensuring adequate level of anesthesia and analgesia, and confirming proper positioning of the 18G cannula, apnea was induced by the administration of myorelaxant and the SpO2 was allowed to drop to 75% before initiating rescue ventilation via either the OFM or jet ventilator.ResultsFive rabbits were ventilated with the OFM and four with the jet ventilator. Ventilation was maintained with either device for 15 min. All rabbits were successfully rescued using either device. There was no statistical difference in the time required for SpO2 to return to 80%, 85%, 90%, and 95%.ConclusionsBoth devices facilitated successful rescue ventilation through a needle cricothyrotomy.
Implicit memory formation using the word stem completion task during anesthesia in children
Authors: Bonett Emily , Pham Xiuzhi , Smith Katherine R. , Howard Kelly , Sheppard Suzette , Davidson Andrew 
Published: November 2013

SummaryAimsTo determine whether there is evidence of implicit memory formation during pediatric anesthesia using the word stem completion task.BackgroundIn adults, there is mixed evidence for implicit memory formation during anesthesia; however, there is no evidence in children. Implicit memory in adults has been detected using the word stem completion task. This test has not been used in a pediatric anesthetic setting.MethodsA total of 200 patients aged 7–12 were randomized to hear one of the two lists of 10 words played continuously while anesthetized. Group 1 heard List A and Group 2 heard List B. Postoperatively, 194 completed a word stem completion task where they were required to complete the stems (the first part of words) corresponding to the words on the two word lists combined, with the first word that came to mind.ResultsGroup 1 completed a mean of 2.78 words correctly from List A and a mean of 2.70 words correctly from List B. Group 2 completed a mean of 3.29 words correctly from List A and a mean of 3.66 words correctly from List B. For List A, there was no evidence (P = 0.70) for an association between intraoperative exposure to this list and the odds of successfully completing a stem from this list with the corresponding target word. There was little evidence (P = 0.09) for an association with List B.ConclusionThis study found no strong evidence that children form implicit memories for auditory words during anesthesia. Given the difference between lists, future research is warranted using carefully chosen word stems.
The Role of Pain Catastrophizing in Experimental Pain Perception
Authors: Kristiansen Frederik L. , Olesen Anne E. , Brock Christina , Gazerani Parisa , Petrini Laura , Mogil Jeffrey S. , Drewes Asbjørn M. 
Published: November 2013

AbstractBackgroundPain is a subjective experience influenced by multiple factors, and tremendous variety within individuals is present. To evaluate emotional state of pain, catastrophizing score can be used. This study investigated pain catastrophizing ratings in association with experimental pain perception.MethodExperimental pain was induced using thermal heat and cold stimulation of skin, mechanical stimulation of muscle and bone, and thermal, mechanical, and electrical stimulation of the gastrointestinal tract in healthy participants (N = 41). Prior to experimental sessions, a pain catastrophizing questionnaire was filled out by each participant.ResultsBased on the median catastophizing score, participants were divided into two groups: noncatastrophizers and low‐catastrophizers. No significant difference was found between low‐catastrophizers and noncatastrophizers in thermal heat stimulation of skin, mechanical stimulation of muscle and bone, and rectal electrical stimulation (All P > 0.05). Low‐catastrophizers were more sensitive to visceral thermal stimulation (4.7%, P = 0.02) and visceral mechanical stimulation (29.7%, P = 0.03). For participants that completed the 120 seconds ice water stimulation, noncatastrophizers reported 13.8% less pain than low‐catastrophizers (P = 0.02). A positive correlation between PCS score and pain perception on cold pressor test was found (r = 0.4, P = 0.02). By extrapolating data, further analysis of the total group was performed and no differences (both P > 0.05) were observed.ConclusionEven small increments in pain catastrophizing score can influence pain perception to deep and tonic stimulations. Catatrophizing may partly explain the variability found in experimental pain studies.
Engineering a Pressurised Wind Tunnel Aimed at Developing CO2 Turbomachinery
Authors: Sánchez D. , Monje B. , Chacartegui R. , Barragán J. M. , Pajuelo E. , Gómez J. R. , Sánchez T. 
Published: November 2013

The number of people researching the supercritical CO2 power cycle has largely increased in the last few years. Just to mention, in contrast to the one or two technical papers in the topic submitted yearly to Turbo Expo until 2011, the number of contributions in the topic has rocketed to twenty in the last conference held in Copenhagen. Such astounding and unexpected growth has eventually given rise to the International Gas Turbine Institute creating a new dedicated technical committee. Nevertheless, in spite of the large attention captured by the SCO2 power cycle, most efforts are devoted to the adaption of existing equipment (turbomachinery and heat exchangers) rather than to analysing the particular features of this unconventional working fluid. Hence, the test plants already in operation as well as the numerous CFD analyses under development rely on the existing ideal-gas based knowledge typically used by the gas turbine industry. This is the reason why the compressors in these test plants are far from their theoretical performance (typically 65% real vs. 80% theoretical efficiency).
The partnership formed by the University of Seville and Altran has engineered a first-of-a-kind wind tunnel for aerodynamic testing of carbon dioxide flows at high pressure. This unique facility incorporates special features like new seals, variable pressure operation and remote data acquisition which cannot be adapted from conventional wind tunnels. This development is expected to provide the industry with a tool to increase the efficiency of SCO2 turbomachinery by large what would eventually allow for a faster and wider deployment of the technology. The university of Seville and Altran are currently raising capital to construct the facility.
Compressor Modifications for 300 MW IGCC Gas Turbine Stable Behaviour
Authors: Cerri Giovanni , Basilicata Carmine , Giovannelli Ambra 
Published: November 2013

Economic reasons, leading to the use of coal and the environmental concerns, call for clean technologies for the electric power production. Accordingly the adoption of Integrated Gasification Combined Cycle (IGCC) plants with Carbon Capture and Storage (CCS) has been pushed. Such a technology is promising but it still shows some critical aspects. Some of them are related to stable and controllable operations of commercially available Gas Turbines (GTs) designed to be fed with Natural Gas (NG) once the original fuel is replaced by the hydrogen-rich syngas produced in an IGCC-CCS plant.
The thermo-physical properties of the H2-rich syngas require investigations and modifications of the combustor and of the turbomachines to meet stable and safe GT behaviour. Such properties strongly affect the matching between GT compressor and expander.
To run the GT with the syngas, various options can be taken into account. Some of them do not require GT flow function modifications, while other options involve compressor and expander structural changes.
In the present paper some compressor modifications that can be adopted to maintain an F Class GT performance and stability are explored. Such modifications have been analysed by means of a high fidelity quasi-one-dimensional model based on an Elemental Component Finite Volume approach for the GT sizing and analysis. Results have been compared and deeply discussed.
Labyrinth Seal and Pocket Damper Seal High Pressure Rotordynamic Test Data
Authors: Vannini Giuseppe , Cioncolini Stefano , Del Vescovo Giuseppe , Rovini Massimiliano 
Published: November 2013

The current centrifugal compressor design for the Oil & Gas market is more and more challenging, and the presence of many competitors is pushing technology towards both a casing size reduction and a rotational speed increase. The first point is leading to an increase in the number of wheels per rotor (to do the same service), and the second point is forcing to cross two or even three rotor modes (hence a higher control of rotor damping is necessary). The two points together are leading to increase the rotor “Flexibility Ratio” (defined as the ratio between the Maximum Continuous Speed and the first critical speed at infinite support stiffness according to [1]), and finally the rotordynamic stability is very much challenged.
The centrifugal compressors rotordynamic stability is strongly related to the internal seals’ dynamic behaviour, and for this reason, the authors’ company decided several years ago to develop internally a High Pressure Seal Test Rig [2] to measure internal seals stiffness and damping. The rig is now in operation, and in a previous paper the authors described its main capabilities, the applied identification procedures and the preliminary test results captured for a long Labyrinth seal (smooth rotor, straight toothed stator) tested up to 200bar.
This paper is intended to show more data for the same long Laby with special focus on some peculiar test as:
• Negative preswirl test
• Single frequency vs. Multi-frequency test
• Offset vs. Centered Seal test
The negative preswirl test shows a drastic change in the effective damping (from destabilizing to stabilizing) and provides a support in favor of the selection of swirl reversal devices at seals upstream.
The multi-frequency excitation test approach (based on the concurrent presence of several frequencies not multiples at each other) is compared with a single frequency excitation providing similar results and thus confirming the soundness of the multiple effects linear superimposition assumption.
The effect of a static offset (simulating the real position of a rotor inside an annular seal) is also investigated proving that the relevant impact is negligible within the range of eccentricity explored (10% of seal clearance).
Moreover, a Pocket Damper Seal (PDS) with the same nominal diameter, clearance and effective length has been tested (up to 300bar) and compared with the Laby. As expected, the PDS shows both a higher effective stiffness and damping at the same test conditions, so the promising results already collected in a previous test campaign which was performed on a smaller scale and lower pressure test rig [3] were mostly confirmed with the only exception for the effective damping cross-over frequency which was lower than expected.
Anti-Optimisation Applied to the Analysis of Rotor/Stator Interaction
Authors: Butlin Tore , Batailly Alain 
Published: November 2013

There is a drive towards minimising operating clearances within turbomachines in order to limit reverse leakage flows and hence improve their efficiency. This increases the likelihood of contact occurring between the blade and the casing, which can give rise to high amplitude vibration. Modelling this interaction represents a significant computational challenge. The non-linear contact precludes the use of well-established linear methods, and is also subject to uncertainties: the contact law is imprecisely known and the exact geometry of imperfections that trigger contact may be unknown.
In this paper a novel approach is presented that aims to account for the uncertainties associated with the non-linearity in a non-probabilistic way. The worst case is sought, by framing the system as a constrained anti-optimisation problem. The target to be maximised represents a metric of the output of interest. The degrees of freedom of the anti-optimisation are the non-linear input forces (considered as external loads), and the constraints are designed to capture what is thought to be known about the non-linear contact law and geometry.
A realistic three-dimensional model of a turbine blade is used to explore the approach, with contact considered at the leading and trailing edge. The blade dynamics are described in terms of a linear transfer function matrix and the target metric of interest is chosen to be the peak displacement of the contact points. The non-linearity is taken to result from an offset shaft, giving a sinusoidal clearance variation. The blade is driven at constant frequency and the scope of the study is limited to finding bounds on periodic solutions. A variety of constraint conditions are explored that describe aspects of the non-linearity. For example, only compressive forces are permitted (no tension from the contact), and the displacement must not exceed the clearance.
The method yields encouraging initial results: constraints can be identified that give efficient estimates of the upper bound response of the system as a function of drive frequency. The results are compared with a benchmark time-domain simulation and are found to correctly over-predict the response without being overly conservative. Broad trends are also in agreement with the benchmark solution. The proposed method appears to be a promising approach for efficiently accounting for uncertainties associated with the non-linearity and thus improving blade design.
Common Practice for Verification of Integrity of New Emerging Technologies for Heavy Crude Oil Pumping Applications
Authors: Delgado Hector , Kurz Rainer , Brun Klaus 
Published: November 2013

In the current emerging development of technologies for heavy crude oil pumping, it is essential to be able to predict and verify the reliable operation of new pumping technologies. Engineering studies are required for verification of the reliable operation of crude oil pumps and pumping systems. The specific requirements to be met by the pump and pumping system for ensuring reliable operation vary depending on their characteristics. However, it has been commonly based on the author’s experience to perform several analyses specifically for heavy crude oil applications including positive displacement pumps. Such analyses include skid mechanical vibration study, coupled acoustic-mechanical piping analysis, and lateral and torsional rotordynamic study.
This paper presents a case study where the previously mentioned studies are conducted for a gas turbine driven screw pump train. A lateral rotordynamic analysis has been conducted by the turbomachinery original equipment manufacturer (OEM) and its details are not included in this paper. The results from the skid mechanical vibration study confirm that vibration issues are not predicted during normal or transient operation. A coupled acoustic-mechanical analysis identifies areas of concern that can then be addressed to avoid excessive vibration levels on the piping. Finally, results from a torsional rotordynamic study verify that vibration levels are expected to be within allowable limits.
Study on the Influence of Total Pressure Distortion on End Wall Flow Field in a Supersonic Compressor
Authors: Sun Peng , Gao Haiyang , Zhong Jingjun , Yang Muxiao 
Published: November 2013

Inlet total pressure distortion has great effects on the performance and stability of compressors. The Non-uniform flow influences the flow field of rotor tip and stator hub more significantly. If stall occurs, it often begins in one or both of these two regions. Which region is more sensitive to the nonuniform flow and how the mechanism of distorted flow influences the compressor flow field are topics of great importance and should be studied carefully.
In this paper, the exploration of how the inlet total pressure distortion influences the flow field of rotor and stator end walls will base on the study of one-stage supersonic compressor with one rotor and one stator. Two aspects of the results will be analyzed in detail. The first aspect is about the dynamic response of shock wave to the inlet parameters in rotor casing area, the variation of shock wave intensity and structure with inlet flow parameters, and the mechanism of shock motion. The process of flow parameters variation in rotor cycle can be divided into four stages. The second aspect is about the analysis on the flow parameters near end walls and development of corner separation in stator. The study indicates that corner separation is induced by the distorted flow near stator hub and casing. Flow structures in each passage are different due to the different positions of distorted regions. The relationship between intensity and range of corner separation, and the change of inlet velocity angle and flow capacity, will be discussed in detail.