bluuebunny/crossref_metadata_2025 huggingface dataset:
Unsteady Wake-Induced Boundary Layer Transition in High Lift LP Turbines
Authors: Schulte Volker , Hodson Howard P.
Published: February 2015

The development of the unsteady suction side boundary layer of a highly loaded LP turbine blade has been investigated in a rectilinear cascade experiment. Upstream rotor wakes were simulated with a moving-bar wake generator. A variety of cases with different wake-passing frequencies, different wake strength and different Reynolds-numbers were tested. Boundary layer surveys have been obtained with a single hot-wire probe. Wall shear stress has been investigated with surface-mounted hot-film gauges. Losses have been measured.

The suction surface boundary layer development of a modern highly loaded LP turbine blade is shown to be dominated by effects associated with unsteady wake-passing. Whereas without wakes the boundary layer features a large separation bubble at a typical cruise Reynolds-number, the bubble was largely suppressed if subjected to unsteady wake-passing at a typical frequency and wake strength. Transitional patches and becalmed regions, induced by the wake, dominated the boundary layer development. The becalmed regions inhibited transition and separation and are shown to reduce the loss of the wake-affected boundary layer.

An optimum wake-passing frequency exists at cruise Reynolds-numbers. For a selected wake-passing frequency and wake-strength, the profile loss is almost independent of Reynolds-number. This demonstrates a potential to design highly loaded LP turbine profiles without suffering large losses at low Reynolds-numbers.
Investigation of the Calmed Region Behind a Turbulent Spot
Authors: Gostelow J. P. , Walker G. J. , Solomon W. J. , Hong G. , Melwani N.
Published: February 2015

Measurements are presented of the calmed region behind triggered wave packets and turbulent spots under a controlled diffusion adverse pressure gradient in a wind tunnel. Similar measurements are also presented from the stator blades of an axial flow compressor, where turbulent spots are induced by the passing of rotor wakes. The purpose is to gain an appreciation of turbulent spot behavior under a strong adverse pressure gradient as a foundation for the more accurate modeling of spots and their environment in predictions of transitional boundary layer flows. Under an adverse pressure gradient the calmed region behind the spot is extensive; its interaction with the surrounding turbulent layer is complex and is dependent on whether the surrounding natural boundary layer is laminar or turbulent. Some insights are gleaned concerning the behavior of the calmed region which will subsequently be used in attempts to model the calmed region. Although these fundamental investigations of the calmed region have been extensive much remains to be understood.
An Experimental Investigation of the Velocity and Temperature Fields of Cold Jets Injected Into a Hot Crossflow
Authors: Rydholm Hans A.
Published: February 2015

It is shown here by dimensional analysis that the near-wall flow field of an effusion cooled combustor, can be scaled if the Reynolds, Mach and Prandtl numbers and the temperature and velocity ratios are kept constant. It is also demonstrated that a practical model experiment can be designed, which fulfils all the scaling laws. A test rig meeting these requirements has been designed, built and tested. The experimental conditions have been chosen to correspond to the conditions usually met in a real effusion cooled combustion chamber.

One geometrical configuration has been investigated. This consists of one transverse row of holes drilled with a 30° angle to the wall through which the cooling air enters into a cross flowing mainstream. The mean values of all three velocity components and the three normal fluctuating Reynolds stresses as well as the mean temperature have been measured in a large number of points surrounding the central injection hole.

Experiments were carried out for jet-to mainstream density ratios of 1.2 and 1.8 and the results indicate that realistic density ratios are necessary to provide data directly applicable in effusion cooling design.
SNECMA Experience With Cost Effective DS Airfoil Technology Applied Using CM 186 LC® Alloy
Authors: Caruel F. , Bourguignon S. , Lallement B. , Fargeas S. , DeBussac A. , Harris K. , Erickson G. L. , Wahl J. B.
Published: February 2015

From a cost point of view SNECMA has found DS columnar grain manufacturing technology to be highly attractive compared to single crystal. CM 186 LC alloy exhibits enhanced mechanical and environmental properties and temperature capability compared to MAR M 200 Hf alloy; these properties are close to first generation single crystal alloys up to 982°C (1800°F). The alloy is shown to be amenable to various coating and brazing high temperature processes. The longer term creep-rupture/phase stability data base on the alloy has now been extended out to 8300 hours at 1038°C (1900°F). Castings for engine test have been produced using CM 186 LC alloy.
Some Significant Highlights in Allison Regenerator Development
Authors: Davis Leonard C. , Jackman Anthony J.
Published: February 2015

Allison Engine Company has 26 years of experience in vehicular gas turbines with rotating disc regenerators for waste heat recovery including 7 different engine models ranging up to 350 hp. We have completed the first 140 hr of endurance testing on a one-piece extruded ceramic disc regenerator of 231 mm (9.1 in.) diameter. Our disc supplier is finalizing extrusion additives and firing schedule for a lithium aluminum silicate material with up to 85% mined mineral content for low cost.

Unique Allison regenerator experience is cited as follows: first gas turbine with rotating regenerator in production, thermal cyclic strength loss of ceramic disc materials and cyclic oxidation of metal disc materials, regenerator leakage as low as 3.4%, metal regenerator time versus temperature ignition limits of various metals, and damping of friction-induced torsional vibration of regenerator discs.
Influence of Tip-Clearance, Aspect Ratio, Blade Loading, and Inlet Boundary Layer on Secondary Losses in Compressor Cascades
Authors: Hübner Jürgen , Fottner Leonhard
Published: February 2015

Within the scope of a compressor research program on endwall flows a highly loaded linear compressor cascade of NACA 65 profiles was investigated.

Detailed study of the three-dimensional flow field was carried out for three different cases of tip-clearance including zero clearance with a variation of blade loading, blade height, and inlet boundary layer thickness. Using a small five hole probe measurements have been performed inside and downstream of the blade passage. Additional information about the formation and development of the passage and tip-clearance vortices is obtained from static pressure tappings at midspan and on the endwall, and a surface flow visualization technique.

The cascade performance is presented in terms of turning angle and loss coefficient. It is found that in addition to the frequently investigated effects of tip-clearance and blade loading, the displacement thickness of the inlet boundary layer has a significant influence on the radial distribution of the losses and the outlet angle. However, the overall loss behavior remains almost unaffected by the inlet boundary layer. Only for low values of the aspect ratio around one, zero tip-clearance, and high values of incidence the influence of the aspect ratio becomes important. In this case the endwall flow regions from both blade ends are linked.

The experimental results provide an extended basis for the improvement of the known correlations on aerodynamic losses and flow angle deviation as well as for the validation of 3D-Navier-Stokes calculations. An improved approach for loss correlations is presented in this paper.
Effects of Downstream Stator Pressure Field on Upstream Rotor Performance
Authors: Graf Martin B. , Sharma Om P.
Published: February 2015

Results of numerical simulations conducted for a high pressure compressor rotor with two different levels of tip clearance are presented. A three-dimensional, steady, Reynolds-Averaged Navier-Stokes code was utilized to perform the computations. The simulations were executed over a range of flow coefficients by specifying different axisymmetric radial profiles in static pressure downstream of the rotor. In this manner, the effect of the downstream stator row was approximated using a simple, circumferentially averaged, radial pressure profile as the boundary condition behind the rotor. The back pressure profiles utilized were those deduced from inviscid flow computations for two different stator designs: (1) a conventional radial stator, and (2) a three-dimensional “bowed” stator. Results of the rotor simulations with nominal tip clearance show that the boundary condition induced by the bowed stator causes a 2% decrease in rotor pressure rise capability, and a 9% increase in rotor loss as compared with the conventional stator. In addition, as the tip clearance is increased to twice the nominal value, the rotor loss grows at a rate 25% higher for the rotor subjected to the bowed stator pressure profile. Accompanying this is a dramatic reduction in rotor speedline slope and pressure rise capability. Analysis of the simulations shows these effects to be linked to the response of the rotor tip clearance vortex to the exit pressure profile set by the downstream stator. These results indicate the need to accurately model the effects of the radial variation in static pressure imposed by the downstream airfoil rows.
Data Transmission Systems for a Transient Gas Turbine Rotor
Authors: Byrne Catherine M. , Davies Mark R. D.
Published: February 2015

The design and testing of multi-channel data transmission systems for a transient turbine test rotor are presented. Two multi-channel systems were required for the conditioning and transmission of the electrical signals from thin film gauges and un-packaged embedded pressure transducers which are to be used for the measurement of rotor blade surface heat transfer and pressure respectively. All measurements will be taken from the same rotor at design Mach and Reyoolds numbers. Signal conditioning and amplification will be performed in the rotating frame to solve the problems associated with accurate sigoal transmission. Also, the use of a multi-chanoel array of light emitting diodes for data transmission is described which allows accurate signal reconstruction. Both systems have been initially stress screened and are shown to have an adequate bandwidth for resolving wake blade interactions.
Newly Developed Filter Products for Gas Turbine Intake Air Filtration
Authors: Schroth Thomas , Rudolph Antje , Freudenberg Carl
Published: February 2015

The newly developed depth-loading filter types MaxiPleat filter and depth-loading filter cartridge offer gas turbine users numerous advantages in terms of clean air quality in the combustion air, cost-efficiency due to favourable pressure drop, long life and high functional reliability over the entire operating period.

The MaxiPleat filters fitted with a paper-like filter medium are produced by using the patented thermal embossing process, distinctive for its solution to the spacing problem. Without using any foreign materials as separators, depths of 250 mm can be achieved in pleating, with V-shaped, flow-optimized pleat geometries. This ensures low pressure drops and high dust holding capacities.

The depth-loading filter cartridge is intended as a replacement filter for surface-loading filter cartridges given unsatisfactory results. A conventional pulse-jet system can be converted to a depth-loading filter without any expensive modification. The depth-loading filter cartridge extends substantially the useful life of the filters and significantly improves the pressure drop characteristics, especially when sticky dusts and high humidity locations are involved.
35-Year Old Splined-Disc Rotor Design for Large Gas Turbines
Authors: Janssen Manfred J. , Joyce John S.
Published: February 2015

The design principles of the splined-disc-type rotor with Hirth-serration couplings used in all Siemens heavy-duty gas turbines since 1960 are explained. The benefits of this rotor construction are elaborated against the operational requirements imposed on rotors by present-day large advanced gas turbines for electric power generation. Details of the stress assessment, analysis and testing underlying the design, as well as a description of the assembly of the rotor are also presented, using mostly the 170 MW-class 3600 rpm Model V84.3A gas turbine to illustrate the most recent technology.
Improved Turbine Cylinder Bolting System
Authors: Gosling Martin C.
Published: February 2015

This paper describes the design and development of a new Cylinder Bolting System to replace the Main Joint Hardware for both Combustion (and Steam) Turbine applications. The new bolts are designed to be hydraulically tensioned to the specified preloed and utilize ultrasonic verification of elongation. The new Bolting System uses a reduced number of components in each assembly and the individual components themselves are of a simplified design. The new hardware can be applied to new equipment without modification and retrofitted to customer owned equipment as a direct replacement for existing joint hardware. The prototype, production and field testing of this hardware, the installation tooling and ultrasonic elongation measuring equipment is described. This testing has shown significant savings in assembly and disassembly cycle times even after prolonged exposure to turbine operating temperatures in a corrosive environment. The new design of bolting is now standard equipment for the CW251B11/B12 Combustion Turbine manufactured by Westinghouse P.G.B.U.
CTV: A New Method for Mapping a Full Scale Prototype of an Axial Compressor
Authors: Mezzedimi Vasco , Nava Pierluigi , Hamilla Dave
Published: February 2015

The full mapping of a new gas turbine axial compressor at different speeds, IGV settings and pressure ratios (from choking to surge) has been performed utilizing a complete gas turbine with a suitable set of modifications.

The main additions and modifications, necessary to transform the turbine into the Compressor Test Vehicle (CTV), are:

- Compressor inlet throttling valve addition

- Compressor discharge bleed valve addition

- Turbine 1st stage nozzle area reduction

- Starting engine change (increase in output and speed range).

This method has been successfully employed on two different single shaft heavy-duty gas turbines (with a power rating of 11MW and 170 MW respectively).

The paper describes the theoretical basis of this testing method and a specific application with the above mentioned 170 MW machine.
Heat Transfer Measurements to a Gas Turbine Cooling Passage With Inclined Ribs
Authors: Wang Z. , Ireland P. T. , Kohler S. T. , Chew J. W.
Published: February 2015

The local heat transfer coefficient distribution over all four walls of a large scale model of a gas turbine cooling passage have been measured in great detail. A new method of determining the heat transfer coefficient to the rib surface has been developed and the contribution of the rib, at 5% blockage, to the overall roughened heat transfer coefficient was found to be considerable. The vortex dominated flow field was interpreted from the detailed form of the measured local heat transfer contours. Computational Fluid Dynamics calculations support this model of the flow and yield friction factors which agree with measured values. Advances in the heat transfer measuring technique and data analysis procedure which confirm the accuracy of the transient method are described in full.
Design, synthesis, and carbon-heteroatom coupling reactions of organometallic nickel(IV) complexes
Authors: Camasso Nicole M. , Sanford Melanie S.
Published: February 2015

Taking advantage of four for a nickel

Metal atoms change their oxidation state—i.e., lose or gain electrons—relatively easily. This is a major reason why metal compounds accelerate so many chemical reactions. Camasso and Sanford now report a straightforward way to prepare complexes of nickel in the +4 oxidation state, based on careful tuning of the coordination environment around the metal center (see the Perspective by Riordan). These complexes could prove useful in coupling carbon to oxygen, nitrogen, or sulfur, and complement more traditional nickel catalysts that operate in lower oxidation states.

Science
, this issue p.
1218
; see also p.
1203
Complete Genome Sequences of Novel Anelloviruses from Laboratory Rats
Authors: Nishiyama Shoko , Dutia Bernadette M. , Sharp Colin P.
Published: February 2015

Anelloviruses are nonenveloped single-stranded DNA viruses infecting a wide range of mammals. We report three complete genomes of novel anelloviruses detected in laboratory rats. Phylogenetic analysis demonstrates that these viruses are related to but distinct from recently described rodent Torque teno viruses (RoTTVs) found in wild rodent species.
Draft Genome Sequence of Listeria monocytogenes LM201, Isolated from Foodstuff
Authors: Wu Yongpeng , Zheng Jinshui , Wang Yunxiao , Li Shaowen , Jin Hui , Li Zili , Bi Dingren , Sun Ming , Liu Mei
Published: February 2015

Listeria monocytogenes
is a facultative intracellular foodborne pathogen that can cause listeriosis in humans and animals.
L. monocytogenes
LM201 was isolated from foodstuff. The draft genome sequence of strain LM201 provides the genetic basis for the application of this strain in biotechnological vaccine production.
Draft Genome of Escherichia coli O146 Isolate from Maulana Azad Medical College, New Delhi, India
Authors: Rajeshwari K. , Uppal Beena , Singh Rakesh , Malakar Abhishek K. , Chikara Surendra K.
Published: February 2015

Here, we report the draft genome sequence of enteropathogenic
Escherichia coli
(EPEC) O146 strain isolated from a 1-year-old child with acute diarrhea in Delhi who recovered completely. The multidrug transporter (
mdtABCD
) gene, responsible for drug resistance, is present. The strain also contains the
astA
gene, an additional virulence determinant.
Genome Sequence of Sphingobium yanoikuyae B1, a Polycyclic Aromatic Hydrocarbon-Degrading Strain
Authors: Zhao Qiang , Hu Hongbo , Wang Wei , Peng Huasong , Zhang Xuehong
Published: February 2015

Sphingobium yanoikuyae
B1 can utilize biphenyl, naphthalene, phenanthrene, toluene, and m-/p-xylene as sole sources of carbon and energy. Here, we present a 5.2-Mb assembly of its genome. An analysis of the genome can provide insights into the mechanisms of polycyclic aromatic hydrocarbon (PAH) degradation and potentially aid in bioremediation applications.
Draft Genome Sequences of Two Xanthomonas euvesicatoria Strains from the Balkan Peninsula
Authors: Vancheva Taca , Lefeuvre Pierre , Bogatzevska Nevena , Moncheva Penka , Koebnik Ralf
Published: February 2015

We report the draft genome sequences of two
Xanthomonas euvesicatoria
strains from the Balkan Peninsula, which were isolated from symptomatic pepper plants. The availability of these genome sequences will facilitate the development of modern genotyping assays for X. euvesicatoria strains and to define targets for resistance breeding.
Giant prolactinoma mimicking low-tension glaucoma at presentation
Authors: Karl David , Gillan Stewart Neil , Goudie Colin , Sanders Roshini
Published: February 2015

We describe a case of a 68-year-old man, referred by his optometrist with suspected low-tension glaucoma, who presented with advanced cupped optic discs and field of vision loss that were subsequently found to be due to a giant prolactinoma. Failing vision in low-tension glaucoma suspects should have a low threshold for neuroimaging.
Emergent interventional approach for aortogastric tube fistula with massive gastrointestinal bleeding
Authors: Kuhara Asako , Koganemaru Masamichi , Onitsuka Seiji , Abe Toshi
Published: February 2015

This report describes the successful endovascular treatment of a rare case of aortogastric tube fistula with massive gastrointestinal haemorrhage. The patient's history included oesophageal reconstruction for oesophageal carcinoma using a gastric tube. Emergent angiography revealed extravasation from the thoracic aorta into the thinner aortogastric tube fistula. A microcatheter was inserted into the aortogastric tube with the aortic approach for embolisation with a mixture ofn-butyl cyanoacrylate and iodised oil to enable fluoroscopic visualisation. Aortography confirmed the complete absence of extravasation after embolisation, after which a stent graft was placed. This procedure demonstrated that transcatheter embolisation of the aortogastric tube fistula was possible, and that the technique can be used as an emergency option. CT imaging was performed 21 days after the procedure, and revealed no trace of extravasation or inflammation. There were no complications during the 14 months following the endovascular treatment; the patient remains in stable condition.
Diffuse alveolar haemorrhage secondary to propylthiouracil-induced vasculitis
Authors: Ferreira Catarina , Costa Teresa , Marques Ana Vieira
Published: February 2015

Propylthiouracil is a drug used to treat hyperthyroidism. It can cause several side effects including pulmonary disorders that, although rare, can be severe. The authors describe the case of a woman treated with propylthiouracil who developed diffuse alveolar haemorrhage with severe respiratory failure and anaemia, which improved with discontinuation of the antithyroid drug and on starting systemic corticosteroid therapy.
The effect of preinjury warfarin use on mortality rates in trauma patients: a European multicentre study
Authors: Lecky Fiona E , Omar Mahad , Bouamra Omar , Jenks Tom , Edwards Antoinette , Battle Ceri E , Evans Phillip A
Published: February 2015

Objective

To define the relationship between preinjury warfarin use and mortality in a large European sample of trauma patients.

Methods

A multicentred study was conducted using data collated from European (predominately English and Welsh) trauma receiving hospitals. Patient data from the Trauma Audit and Research Network database from 2009 to 2013 were analysed. Univariate and multivariate logistic regression was used to estimate OR for mortality associated with preinjury warfarin use in the whole adult trauma cohort and a matched sample of patients comparable in terms of age, gender, GCS, pre-existing medical conditions and injury severity.

Results

A total of 136 617 adult trauma patients (2009–2013) were included, with 499 patients reported to be using warfarin therapy at the time of trauma. Preinjury warfarin use was associated with a significantly higher mortality rate at 30 days postinjury compared with the non-users. Following adjustment of age, injury severity and GCS, preinjury warfarin use was associated with increased mortality in trauma patients (adjusted OR 2.14; 95% CI 1.66 to 2.76; p<0.001). In the matched subset, 22% of warfarinised trauma patients died compared with 16.3% of non-warfarinised trauma patients with comparable age, injury severity and GCS (adjusted OR 1.94; 95% CI 1.25 to 3.01; p=0.003).

Conclusions

Preinjury warfarin use has been demonstrated to be an independent predictor of mortality in trauma patients. Clinicians managing major trauma patients on warfarin need to be aware of the vulnerability of this group.
A genome-wide identification and classification of basic helix-loop-helix genes in the jewel wasp,Nasonia vitripennis(Hymenoptera: Pteromalidae)
Authors: Liu Xiao-Ting , Wang Yong , Wang Xu-Hua , Tao Xia-Fang , Yao Qin , Chen Ke-Ping
Published: February 2015

Basic helix-loop-helix (bHLH) proteins are highly conserved DNA-binding transcription factors of a large superfamily. Animal bHLH proteins play important regulatory roles in various developmental processes such as neurogenesis, myogenesis, heart development, and hematopoiesis. The jewel wasp (Nasonia vitripennis) is a good model organism of hymenoptera insects for studies of developmental and evolutionary genetics. In this study, we identified 48 bHLH genes in the genome of N. vitripennis. According to phylogenetic analysis, based on N. vitripennis bHLH (NvbHLH) motif sequences and structural domain distribution in their full-length protein sequences, the identified NvbHLH genes were classified into 36 bHLH families with 19, 12, 9, 1, 6, and 1 member(s) in groups A, B, C, D, E, and F, respectively. Our classification to the identified NvbHLH family members confirms GenBank annotations for 21 of the 48 NvbHLH proteins and provides useful information for further characterization and annotation of the remaining 27 NvbHLH proteins. Compared to other insect species, N. vitripennis has the lowest number of bHLH family members. No NvbHLH members have been found in the families Net, MyoRa, and PTFa, while all other insect species have at least one member in each of the families. These data constitute a solid basis for further investigations into the functions of bHLH proteins in developmental regulation of N. vitripennis.
A New SVM Kernel for Keyword Spotting Using Confidence Measures
Authors: Ben Ayed Yassine
Published: February 2015

In this paper, we propose an alternative keyword spotting method relying on confidence measures and support vector machines. Confidence measures are computed from phone information provided by a Hidden Markov Model based speech recognizer. We use three kinds of techniques, i.e., arithmetic, geometric and harmonic means to compute a confidence measure for each word. The acceptance/rejection decision of a word is based on the confidence vector processed by the SVM classifier for which we propose a new Beta kernel. The performance of the proposed SVM classifier is compared with spotting methods based on some confidence means. Experimental results presented in this paper show that the proposed SVM classifier method improves the performances of the keyword spotting system.
Monte Carlo and Experimental Magnetic Studies of Molecular Spintronics Devices
Authors: Tyagi Pawan , D'Angelo Christopher , Baker Collin
Published: February 2015

Molecule-based spintronics devices (MSDs) are highly promising candidates for discovering advanced logic and memory computer units. An advanced MSD will require the placement of paramagnetic molecules between the two ferromagnetic (FM) electrodes. Due to extreme fabrication challenges, only a couple of experimental studies could be performed to understand the effect of magnetic molecules on the overall magnetic and transport properties of MSDs. To date, theoretical studies mainly focused on charge and spin transport aspects of MSDs; there is a dearth of knowledge about the effect of magnetic molecules on the magnetic properties of MSDs. This paper investigates the effect of magnetic molecules, with a net spin, on the magnetic properties of 2D MSDs via Monte Carlo (MC) simulations. Our MC simulations encompass a wide range of MSDs that can be realized by establishing different kinds of magnetic interactions between molecules and FM electrodes at different temperatures. The MC simulations show that ambient thermal energy strongly influenced the molecular coupling effect on the MSD. We studied the nature and strength of molecule couplings (FM and antiferromagnetic) with the two electrodes on the magnetization, specific heat and magnetic susceptibility of MSDs. For the case when the nature of molecule interaction was FM with one electrode and antiferromagnetic with another electrode the overall magnetization shifted toward zero. In this case, the effect of molecules was also a strong function of the nature and strength of direct coupling between FM electrodes. In the case when molecules make opposite magnetic couplings with the two FM electrodes, the MSD model used for MC studies resembled with the magnetic tunnel junction based MSD. The experimental magnetic studies on these devices are in agreement with our theoretical MC simulations results. Our MC simulations will enable the fundamental understanding and designing of a wide range of novel spintronics devices utilizing a variety of molecules, nanoclusters and quantum dots as the device elements.
Facile preparation of size-controlled TiO2 nanoparticles by hot-filament metal oxide deposition method and their gas sensing properties to NO2
Authors: San Xiaoguang , Xu Weiwei , Wang Guosheng , Liang Bing , Hou Nannan , Meng Fanli
Published: February 2015

Titanium dioxide ( TiO 2) nanoparticles were prepared by resistive heating Ti filament under an oxygen atmosphere. The obtained nanoparticles were confirmed to be a tetragonal crystal TiO 2 and the particle size increased with increasing the oxygen pressure. The NO 2 gas sensing properties of the TiO 2 nanoparticles were investigated. All the sensors made of TiO 2 nanoparticles with different particle sizes exhibited the maximum sensitivities to 1 ppm NO 2 at a relative low operating temperature of 150°C. Comparing with the large particle size of TiO 2 nanoparticles, the ones with the smallest particle size exhibited the highest sensitivity and the best response and recovery characteristic to various NO 2 gas concentrations.
Sex-dependent expression of water channel AQP1 along the rat nephron
Authors: Herak-Kramberger Carol M. , Breljak Davorka , Ljubojević Marija , Matokanović Mirela , Lovrić Mila , Rogić Dunja , Brzica Hrvoje , Vrhovac Ivana , Karaica Dean , Micek Vedran , Dupor Jana Ivković , Brown Dennis , Sabolić Ivan
Published: February 2015

In the mammalian kidney, nonglycosylated and glycosylated forms of aquaporin protein 1 (AQP1) coexist in the luminal and basolateral plasma membranes of proximal tubule and descending thin limb. Factors that influence AQP1 expression in (patho)physiological conditions are poorly known. Thus far, only angiotensin II and hypertonicity were found to upregulate AQP1 expression in rat proximal tubule in vivo and in vitro (Bouley R, Palomino Z, Tang SS, Nunes P, Kobori H, Lu HA, Shum WW, Sabolic I, Brown D, Ingelfinger JR, Jung FF. Am J Physiol Renal Physiol 297: F1575–F1586, 2009), a phenomenon that may be relevant for higher blood pressure observed in men and male experimental animals. Here we investigated the sex-dependent AQP1 protein and mRNA expression in the rat kidney by immunochemical methods and qRT-PCR in tissue samples from prepubertal and intact gonadectomized animals and sex hormone-treated gonadectomized adult male and female animals. In adult rats, the overall renal AQP1 protein and mRNA expression was ∼80% and ∼40% higher, respectively, in males than in females, downregulated by gonadectomy in both sexes and upregulated strongly by testosterone and moderately by progesterone treatment; estradiol treatment had no effect. In prepubertal rats, the AQP1 protein expression was low compared with adults and slightly higher in females, whereas the AQP1 mRNA expression was low and similar in both sexes. The observed differences in AQP1 protein expression in various experiments mainly reflect changes in the glycosylated form. The male-dominant expression of renal AQP1 in rats, which develops after puberty largely in the glycosylated form of the protein, may contribute to enhanced fluid reabsorption following the androgen- or progesterone-stimulated activities of sodium-reabsorptive mechanisms in proximal tubules.
Decreased muscle endurance associated with diabetic neuropathy may be attributed partially to neuromuscular transmission failure
Authors: Allen Matti D. , Kimpinski Kurt , Doherty Timothy J. , Rice Charles L.
Published: February 2015

Diabetic polyneuropathy (DPN) can cause muscle atrophy, weakness, contractile slowing, and neuromuscular transmission instability. Our objective was to assess the response of the impaired neuromuscular system of DPN in humans when stressed with a sustained maximal voluntary contraction (MVC). Baseline MVC and evoked dorsiflexor contractile properties were assessed in DPN patients ( n = 10) and controls ( n = 10). Surface electromyography was used to record tibialis anterior evoked maximal compound muscle action potentials (CMAPs) and neuromuscular activity during MVCs. Participants performed a sustained isometric dorsiflexion MVC for which task termination was determined by the inability to sustain ≥60% MVC torque. The fatigue protocol was immediately followed by a maximal twitch, with additional maximal twitches and MVCs assessed at 30 s and 2 min postfatigue. DPN patients fatigued ∼21% more quickly than controls ( P < 0.05) and featured less relative electromyographic activity during the first one-third of the fatigue protocol compared with controls ( P < 0.05). Immediately following fatigue, maximal twitch torque was reduced similarly (∼20%) in both groups, and concurrently CMAPs were reduced (∼12%) in DPN patients, whereas they were unaffected in controls ( P > 0.05). Twitch torque and CMAP amplitude recovered to baseline 30 s postfatigue. Additionally, at 30 s postfatigue, both groups had similar (∼10%) reductions in MVC torque relative to baseline, and MVC strength recovered by 2 min postfatigue. We conclude DPN patients possess less endurance than controls, and neuromuscular transmission failure may contribute to this greater fatigability.
Investigation of Dietary Factors and Endometrial Cancer Risk Using a Nutrient-wide Association Study Approach in the EPIC and Nurses' Health Study (NHS) and NHSII
Authors: Merritt Melissa A. , Tzoulaki Ioanna , Tworoger Shelley S. , De Vivo Immaculata , Hankinson Susan E. , Fernandes Judy , Tsilidis Konstantinos K. , Weiderpass Elisabete , Tjønneland Anne , Petersen Kristina E.N. , Dahm Christina C. , Overvad Kim , Dossus Laure , Boutron-Ruault Marie-Christine , Fagherazzi Guy , Fortner Renée T. , Kaaks Rudolf , Aleksandrova Krasimira , Boeing Heiner , Trichopoulou Antonia , Bamia Christina , Trichopoulos Dimitrios , Palli Domenico , Grioni Sara , Tumino Rosario , Sacerdote Carlotta , Mattiello Amalia , Bueno-de-Mesquita H.B(as). , Onland-Moret N. Charlotte , Peeters Petra H. , Gram Inger T. , Skeie Guri , Quirós J. Ramón , Duell Eric J. , Sánchez María-José , Salmerón D. , Barricarte Aurelio , Chamosa Saioa , Ericson Ulrica , Sonestedt Emily , Nilsson Lena Maria , Idahl Annika , Khaw Kay-Tee , Wareham Nicholas , Travis Ruth C. , Rinaldi Sabina , Romieu Isabelle , Patel Chirag J. , Riboli Elio , Gunter Marc J.
Published: February 2015

Data on the role of dietary factors in endometrial cancer development are limited and inconsistent. We applied a “nutrient-wide association study” approach to systematically evaluate dietary risk associations for endometrial cancer while controlling for multiple hypothesis tests using the false discovery rate (FDR) and validating the results in an independent cohort. We evaluated endometrial cancer risk associations for dietary intake of 84 foods and nutrients based on dietary questionnaires in three prospective studies, the European Prospective Investigation into Cancer and Nutrition (EPIC; N = 1,303 cases) followed by validation of nine foods/nutrients (FDR ≤ 0.10) in the Nurses' Health Studies (NHS/NHSII; N = 1,531 cases). Cox regression models were used to estimate HRs and 95% confidence intervals (CI). In multivariate adjusted comparisons of the extreme categories of intake at baseline, coffee was inversely associated with endometrial cancer risk (EPIC, median intake 750 g/day vs. 8.6; HR, 0.81; 95% CI, 0.68–0.97, Ptrend = 0.09; NHS/NHSII, median intake 1067 g/day vs. none; HR, 0.82; 95% CI, 0.70–0.96, Ptrend = 0.04). Eight other dietary factors that were associated with endometrial cancer risk in the EPIC study (total fat, monounsaturated fat, carbohydrates, phosphorus, butter, yogurt, cheese, and potatoes) were not confirmed in the NHS/NHSII. Our findings suggest that coffee intake may be inversely associated with endometrial cancer risk. Further data are needed to confirm these findings and to examine the mechanisms linking coffee intake to endometrial cancer risk to develop improved prevention strategies. Cancer Epidemiol Biomarkers Prev; 24(2); 466–71. ©2015 AACR.
Improved Innate Immune Responses by Frondanol A5, a Sea Cucumber Extract, Prevent Intestinal Tumorigenesis
Authors: Janakiram Naveena B. , Mohammed Altaf , Bryant Taylor , Lightfoot Stan , Collin Peter D. , Steele Vernon E. , Rao Chinthalapally V.
Published: February 2015

Sea cucumbers are a source of antibacterial, anti-inflammatory, and anticancer compounds. We show that sea cucumber extract Frondanol A5 is capable of enhancing innate immune responses and inhibiting intestinal tumors in APCMin/+ mice. APCMin/+ mice were fed semi-purified diets containing 0, 250, or 500 ppm FrondanolA5 for 14 weeks before we assessed intestinal tumor inhibition. Dietary Frondanol A5 suppressed small intestinal polyp sizes and formation up to 30% (P < 0.02) in males and up to 50% (P < 0.01) in females. Importantly, 250 and 500 ppm Frondanol A5 diet suppressed colon tumor multiplicities by 65% (P < 0.007) and 75% (P < 0.0001), compared with untreated male APCMin/+ mice. In female APCMin/+ mice, both dose levels of Frondanol A5 suppressed colon tumor multiplicities up to 80% (P < 0.0001). Isolated peritoneal macrophages from treated mice showed increased phagocytosis efficiency (control 24% vs. treated 50%; P < 0.01) and an increase in GILT mRNA expression, indicating increased innate immune responses by these cells in treated animals. Similarly, we observed an increase in GILT expression in treated tumors, compared with untreated tumors. Furthermore, an increase in G-CSF cytokine, a decrease in inflammatory cytokines and marker 5-LOX, its regulator FLAP, proliferation (PCNA), and angiogenesis (VEGF) markers were observed in treatment groups. These data suggest that Frondanol A5 decreased inflammatory angiogenic molecules and increased GILT expression and macrophage phagocytosis. These decreases may have improved the innate immune systems of the treated mice, thus aiding in inhibition of intestinal tumor formation. These results suggest that Frondanol A5 exhibits significant chemopreventive potential against intestinal tumorigenesis. Cancer Prev Res; 8(4); 327–37. ©2015 AACR.
Dissecting the Roles of MicroRNAs in Coronary Heart Disease via Integrative Genomic Analyses
Authors: Huan Tianxiao , Rong Jian , Tanriverdi Kahraman , Meng Qingying , Bhattacharya Anindya , McManus David D. , Joehanes Roby , Assimes Themistocles L. , McPherson Ruth , Samani Nilesh J. , Erdmann Jeanette , Schunkert Heribert ,   Coronary ARteryDIsease Genome wide Replication and Meta-analysis (CARDIoGRAM) Consortium, Courchesne Paul , Munson Peter J. , Johnson Andrew D. , O’Donnell Christopher J. , Zhang Bin , Larson Martin G. , Freedman Jane E. , Levy Daniel , Yang Xia
Published: February 2015

Objective—

The roles of microRNAs (miRNAs) in coronary heart disease (CHD) have not been well characterized. This study sought to systematically characterize the complex genomic architecture of CHD by integrating whole blood miRNA and mRNA expression with genetic variation in 186 CHD cases and 186 controls.

Approach and Results—

At false discovery rate <0.2, 15 miRNAs were differentially expressed between CHD cases and controls. To explore regulatory mechanisms, we integrated miRNA and mRNA expression with genome-wide genotype data to investigate miRNA and mRNA associations and relationships of genetic variation with miRNAs. We identified a large number of correlated miRNA–mRNA pairs and genetic loci that seem to regulate miRNA levels. Subsequently, we explored the relationships of these complex molecular associations with CHD status. We identified a large difference in miRNA–mRNA associations between CHD cases and controls, as demonstrated by a significantly higher proportion of inversely correlated miRNA–mRNA pairs in cases versus controls (80% versus 30%;
P
<1×10
−16
), suggesting a genome-wide shift in the regulatory structure of the transcriptome in CHD. The differentially coexpressed miRNA–mRNA pairs showed enrichment for CHD risk genetic variants affecting both miRNA and mRNA expression levels, implicating a putatively causal role in CHD. Furthermore, 3 miRNAs (miR-1275, miR-365a-3p, and miR-150-5p) were associated with an mRNA coexpression module that was causally linked to CHD and reflected the dysregulation of B-cell centered immune function.

Conclusions—

Our results provide novel evidence that miRNAs are important regulators of biological processes involved in CHD via genetic control and via their tight coexpression with mRNAs.
Direct Evaluation of Myocardial Viability and Stem Cell Engraftment Demonstrates Salvage of the Injured Myocardium
Authors: Kim Paul J. , Mahmoudi Morteza , Ge Xiaohu , Matsuura Yuka , Toma Ildiko , Metzler Scott , Kooreman Nigel G. , Ramunas John , Holbrook Colin , McConnell Michael V. , Blau Helen , Harnish Phillip , Rulifson Eric , Yang Phillip C.
Published: February 2015

Rationale:

The mechanism of functional restoration by stem cell therapy remains poorly understood. Novel manganese-enhanced MRI and bioluminescence reporter gene imaging were applied to follow myocardial viability and cell engraftment, respectively. Human-placenta–derived amniotic mesenchymal stem cells (AMCs) demonstrate unique immunoregulatory and precardiac properties. In this study, the restorative effects of 3 AMC-derived subpopulations were examined in a murine myocardial injury model: (1) unselected AMCs, (2) ckit
+
AMCs, and (3) AMC-derived induced pluripotent stem cells (MiPSCs).

Objective:

To determine the differential restorative effects of the AMC-derived subpopulations in the murine myocardial injury model using multimodality imaging.

Methods and Results:

SCID (severe combined immunodeficiency) mice underwent left anterior descending artery ligation and were divided into 4 treatment arms: (1) normal saline control (n=14), (2) unselected AMCs (n=10), (3) ckit
+
AMCs (n=13), and (4) MiPSCs (n=11). Cardiac MRI assessed myocardial viability and left ventricular function, whereas bioluminescence imaging assessed stem cell engraftment during a 4-week period. Immunohistological labeling and reverse transcriptase polymerase chain reaction of the explanted myocardium were performed. The unselected AMC and ckit
+
AMC–treated mice demonstrated transient left ventricular functional improvement. However, the MiPSCs exhibited a significantly greater increase in left ventricular function compared with all the other groups during the entire 4-week period. Left ventricular functional improvement correlated with increased myocardial viability and sustained stem cell engraftment. The MiPSC-treated animals lacked any evidence of de novo cardiac differentiation.

Conclusion:

The functional restoration seen in MiPSCs was characterized by increased myocardial viability and sustained engraftment without de novo cardiac differentiation, indicating salvage of the injured myocardium.
Comparative Risk of Ischemic Stroke Among Users of Clopidogrel Together With Individual Proton Pump Inhibitors
Authors: Leonard Charles E. , Bilker Warren B. , Brensinger Colleen M. , Flockhart David A. , Freeman Cristin P. , Kasner Scott E. , Kimmel Stephen E. , Hennessy Sean
Published: February 2015

Background and Purpose—

There is controversy and little information about whether individual proton pump inhibitors (PPIs) differentially alter the effectiveness of clopidogrel in reducing ischemic stroke risk. We, therefore, aimed to elucidate the risk of ischemic stroke among concomitant users of clopidogrel and individual PPIs.

Methods—

We conducted a propensity score-adjusted cohort study of adult new users of clopidogrel, using 1999 to 2009 Medicaid claims from 5 large states. Exposures were defined by prescriptions for esomeprazole, lansoprazole, omeprazole, rabeprazole, and pantoprazole—with pantoprazole serving as the referent. The end point was hospitalization for acute ischemic stroke, defined by
International Classification of Diseases Ninth Revision
Clinical Modification codes in the principal position on inpatient claims, within 180 days of concomitant therapy initiation.

Results—

Among 325 559 concomitant users of clopidogrel and a PPI, we identified 1667 ischemic strokes for an annual incidence of 2.4% (95% confidence interval, 2.3–2.5). Adjusted hazard ratios for ischemic stroke versus pantoprazole were 0.98 (0.82–1.17) for esomeprazole; 1.06 (0.92–1.21) for lansoprazole; 0.98 (0.85–1.15) for omeprazole; and 0.85 (0.63–1.13) for rabeprazole.

Conclusions—

PPIs of interest did not increase the rate of ischemic stroke among clopidogrel users when compared with pantoprazole, a PPI thought to be devoid of the potential to interact with clopidogrel.
Magnetic Resonance Imaging in Experimental Stroke and Comparison With Histology
Authors: Milidonis Xenios , Marshall Ian , Macleod Malcolm R. , Sena Emily S.
Published: February 2015

Background and Purpose—

Because the new era of preclinical stroke research demands improvements in validity and generalizability of findings, moving from single site to multicenter studies could be pivotal. However, the conduct of magnetic resonance imaging (MRI) in stroke remains ill-defined. We sought to assess the variability in the use of MRI for evaluating lesions post stroke and to examine the possibility as an alternative to gold standard histology for measuring the infarct size.

Methods—

We identified animal studies of ischemic stroke reporting lesion sizes using MRI. We assessed the degree of heterogeneity and reporting of scanning protocols, postprocessing methods, study design characteristics, and study quality. Studies performing histological evaluation of infarct size were further selected to compare with corresponding MRI using meta-regression.

Results—

Fifty-four articles undertaking a total of 78 different MRI scanning protocols met the inclusion criteria. T
2
-weighted imaging was most frequently used (83% of the studies), followed by diffusion-weighted imaging (43%). Reporting of the imaging parameters was adequate, but heterogeneity between studies was high. Twelve studies assessed the infarct size using both MRI and histology at corresponding time points, with T
2
-weighted imaging–based treatment effect having a significant positive correlation with histology (

;
P
<0.001).

Conclusions—

Guidelines for standardized use and reporting of MRI in preclinical stroke are urgently needed. T
2
-weighted imaging could be used as an effective in vivo alternative to histology for estimating treatment effects based on the extent of infarction; however, additional studies are needed to explore the effect of individual parameters.
Time Course and Predictors of Neurological Deterioration After Intracerebral Hemorrhage
Authors: Lord Aaron S. , Gilmore Emily , Choi H. Alex , Mayer Stephan A.
Published: February 2015

Background and Purpose—

Neurological deterioration (ND) is a devastating complication after intracerebral hemorrhage but little is known about time course and predictors.

Methods—

We performed a retrospective cohort study of placebo patients in intracerebral hemorrhage trials. We performed computed tomographic scans within 3 hours of symptoms and at 24 and 72 hours; and clinical evaluations at baseline, 1-hour, and days 1, 2, 3, and 15. Timing of ND was predefined as follows: hyperacute (within 1 hour), acute (1–24 hours), subacute (1–3 days), and delayed (3–15 days).

Results—

We enrolled 376 patients and 176 (47%) had ND within 15 days. In multivariate analyses of ND by category, hyperacute ND was associated with hematoma expansion (odds ratio [OR], 3.6; 95% confidence interval [CI], 1.7–7.6) and baseline intracerebral hemorrhage volume (OR, 1.04 per mL; 95% CI 1.02–1.06); acute ND with hematoma expansion (OR, 7.59; 95% CI, 3.91–14.74), baseline intracerebral hemorrhage volume (OR, 1.02 per mL; 95% CI, 1.01–1.04), admission Glasgow Coma Scale (OR, 0.77 per point; 95% CI, 0.65–0.91), and interventricular hemorrhage (OR, 2.14; 95% CI, 1.05–4.35); subacute ND with 72-hour edema (OR, 1.03 per mL; 95% CI, 1.02–1.05) and fever (OR, 2.49; 95% CI, 1.01–6.14); and delayed ND with age (OR, 1.11 per year; 95% CI, 1.04–1.18), troponin (OR, 4.30 per point; 95% CI, 1.71–10.77), and infections (OR, 3.69; 95% CI, 1.11–12.23). Patients with ND had worse 90-day modified Rankin scores (5 versus 3;
P
<0.001).

Conclusions—

ND occurs frequently and predicts poor outcomes. Our results implicate hematoma expansion and interventricular hemorrhage in early ND, and cerebral edema, fever, and medical complications in later ND.