bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of the NOx-Emissions of a Swirl Burner in Partially and Fully Premixed Mode on the Basis of Water Channel LIF and PIV Measurements
Authors: Sangl J. , Mayer C. , Sattelmayer T.
Published: November 2013

The paper describes the development and validation of an efficient and cost effective method for the prediction of the NOx emissions of turbulent gas turbine burners in the early burner design phases which are usually focused on the optimization of the swirler aerodynamics and the fuel air mixing. As the method solely relies on non-reacting tests of burner models in the water channel it can be applied before any test equipment for combustion experiments exists.

In order to achieve optimum similarity of fuel air mixing in the water channel tests with engine operation the model is operated at the engine momentum ratio. During the LIF measurements the water flow representing the fuel is doped with fluorescent dye, a plane perpendicular to the length axis near the burner exit plane is illuminated with a 5W Ar-Ion Laser and the fluorescence is recorded with a video camera from downstream. From the video sequences the local probability density functions (PDF) of the dye concentration fluctuations are calculated from the data. Furthermore, the time mean velocity fields are measured with PIV. From the LIF data the PDFs of the local equivalence ratio are derived. Assuming flamelets, the NOx generation in the entire equivalence ratio range observed in the water channel tests is computed using the unstrained freely propagating one-dimensional flame model in Cantera and the GRI3.0 reaction scheme. Although neither flame stretch nor post flame NOx generation were considered the NOx values computed were in excellent agreement with the experimental data from perfectly premixed combustion experiments. The local time averaged NOx mole fraction is obtained by integrating the flamelet NOx over the mixture PDF. Finally the global NOx emission of the burner at the considered operating point is obtained by spatial integration considering the measured velocity field.

The method was validated using a conical swirl burner with two fuel injection stages, allowing the degree of premixedness to be adjusted over a wide range depending on the specific fuel injection scenario. For the case with fuel injection along the air inlet slots NOx values slightly above the minimum NOx limit for perfectly premixed combustion were computed. This is consistent with the emission measurements and indicates finite mixing quality of this injection method. In the partially premixed regime the configurations with potential for low NOx emissions were reliably identified with the LIF and PIV based water channel method. The method also shows the steep increase of the NOx emissions with decreasing degree of premixing observed in the experiments but quantitative predictions would have required a postprocessing of the data from the LIF mixing study with a higher spacial resolution than available.
Heat Transfer Enhancement Using Angled Grooves as Turbulence Promoters
Authors: Saha Krishnendu , Acharya Sumanta
Published: November 2013

An experimental study is conducted on a simulated internal cooling channel of a turbine airfoil using angled grooves and combination of grooves-ribs to enhance the heat transfer from the wall. The grooves are angled at 45° to the mainstream flow direction and combinations of four different geometries are studied that include: (1) angled grooves with a pitch, p/δ = 10, (2) angled groove with a larger pitch, p/δ = 15, (3) combination of angled groove and 45° angled rib, and (4) combination of angled groove with transverse rib. Transient liquid crystal experiments are conducted for a Reynolds number range of 13,000–55,000, and local and averaged heat transfer coefficient values are presented for all the geometries. Pressure drops are measured between the inlet and the exit of the grooved channel and friction factors are calculated. The combination of the angled groove and 45° angled rib provided the highest performance factor of the four cases considered, and these values were higher or comparable to among the best-performing rib geometries (45-degree broken ribs) commonly used in gas turbine airfoils.
The Effects of the Tangential Leans for the Last Stage Nozzles of Steam Turbine
Authors: Ono Hideki , Senoo Shigeki , Kudo Takeshi , Murata Kenichi
Published: November 2013

In general, since the aspect ratio defined by the ratio of blade height and blade cord length of the last stage blades (LSBs) of a low pressure steam turbine is considerably larger compared to those of other stages, there is anxiety concern about the possibility of flow separation in the vicinity of the root section of the blades. In addition to the above fact, possible efficiency deterioration due to supersonic inflow resulting from the usage of longer blades has to be avoided to obtain an efficient steam turbine. In this paper, the effects of various types of leans for the last stage nozzles have been studied with the help of 3D-CFD. Then, several characteristics charts related to the stage performance for each type of lean including the s-shaped lean were created. By applying well-designed s-shaped lean nozzles, the undesirable effect of supersonic inflow could be significantly mitigated, giving a fair improvement in stage efficiency.
Stall Margin Improvement by Use of Casing Treatments
Authors: Pixberg Christian T. , Schiffer Heinz-Peter , Ross M. H. , Cameron J. D. , Morris S. C.
Published: November 2013

The beneficial impact of casing treatments on the stall margin of tip-critical compressors has been proven many times. However, there is still no simple and general method to predict their actual effectiveness. The present work considers the axial velocity deficit that is generally observed at the blade tip. This so called tip-blockage is caused by the tip clearance flow. That is investigated for different configurations of the transonic compressor test facilities in Darmstadt and Notre Dame and the results are presented in this paper. Similar circumferential groove casing treatments were applied to different single-stage and 1.5-stage compressors. They all had a tip critical behavior in common, but exhibited different design philosophies. The effectiveness of similar casing treatments on different stages was observed. A new method for calculating tip-blockage is introduced based on compressor performance and the results of a through-flow tool. A direct link between blockage growth and stall margin improvement was found for circumferential grooves casing treatments. Additionally, the results of an axial slot casing treatment are taken into account.
Impingement Heat Transfer From Jet Arrays on Turbulated Target Walls at Large Reynolds Numbers
Authors: Mhetras Shantanu , Han Je-Chin , Huth Michael
Published: November 2013

Experiments to investigate heat transfer and pressure loss from jet array impingement are performed on the target wall at high Reynolds numbers. Reynolds numbers up to 450,000 are tested. The presence of a turbulated target wall and its effect on heat transfer enhancement against a smooth surface is investigated. Two different jet plate configurations are used with closely spaced holes and with angled as well as normal impingement holes. The test section cross-section is designed to expand along the streamwise direction maintaining the jet plate to target wall distance in order to reduce cross-flow effects. The jet plate holes are chamfered or filleted to minimize pressure loss through the jet plate. Heat transfer and pressure loss measurements are performed on a smooth target wall as well as turbulated target walls. Three turbulators configurations are used with streamwise riblets, short pins and spherical dimples. A steady state heat transfer measurement method is used to obtain the heat transfer coefficients while pressure taps located in the plenum and at several streamwise locations are used to record the pressure losses across the jet plate. Experiments are performed for a range of Reynolds numbers from 50,000 to 450,000 based on average jet hole diameters to cover the incompressible as well as compressible flow regimes. A target wall with short pins provides the best heat transfer with the dimpled target wall giving the lowest heat transfer among the three turbulators geometries studied. Addition of turbulators though does not significantly increase the pressure losses in the test section over the smooth target wall.
Effect of Hydrogen Content on the Gas Turbine Combustion Performance of Synthetic Natural Gas
Authors: Lee Min Chul , Park Seik , Kim Uisik , Kim Sungchul , Yoon Jisu , Joo Seongpil , Yoon Youngbin
Published: November 2013

This paper investigates the effect of hydrogen content on the gas turbine combustion performance of synthetic natural gases to determine whether they are adaptable to industrial gas turbines. Synthetic natural gases which are composed of methane, propane and varying amounts of hydrogen (0%, 1%, 3% and 5%), are tested in ambient pressure and high temperature conditions at the combustion test facility of a 60kWth industrial gas turbine. Combustion instabilities, flame structures, temperatures at nozzle, dump plane and turbine inlet, and emissions of NOx and CO are investigated for the power outputs from 35 to 60kWth. With increasing hydrogen content, combustion instabilities are slightly alleviated and the frequency of pressure fluctuation and heat release oscillation is increased. NOx and CO emissions are almost similar in trends and amounts for all tested fuels, and the undesirable phenomena from addition of hydrogen such as flashback, auto-ignition and overheating of fuel nozzle were not observed. Synthetic natural gas with less than 1% hydrogen showed no difference in gas turbine combustion characteristics, while synthetic natural gases containing hydrogen of over 3% showed a slight difference in combustion instability such as amplitude and frequency of pressure fluctuations and heat release oscillations. From these results, we conclude that the synthetic natural gas containing less than 1% hydrogen is adaptable without retrofitting any part of the combustor, and Korea coal-SNG Quality Standard Bureau is planning to establish the SNG quality standards, guaranteeing hydrogen content of up to 1%.
Experimental and Numerical Investigation of Streamwise Surface Waviness on Axial Compressor Blades
Authors: Winter Katharina , Hartmann Joerg , Jeschke Peter , Lahmer Manfred
Published: November 2013

This paper gives an account of an experimental and numerical assessment of the aerodynamic influence of surface imperfections, in the form of sinusoidal waviness, as typically caused by manufacturing malfunctions, on a highly subsonic compressor blade. This knowledge marks a step forward towards an aerodynamically and commercially adequate zero-scrap-rate industrial manufacturing process of expensive integral parts like integrally bladed rotors. The investigation itself used the following approach. First, five potential setups were identified by intensive numerical pre-examination, differing in respect of the two parameters, wave length and wave height. The setups were investigated in the linear cascade wind tunnel of the IST for three operating conditions, with a peak profile Mach number around one, all at constant Reynolds number. It was possible to confirm three main effects responsible for higher losses due to surface waviness. These were: an acceleration on the raising edge of the wave; small shock systems on the first two wave crests; and a shock-induced separation in the wave hollow which leads to a strong shear layer.
Exploitation of Subharmonics for Separated Shear Layer Control on a High-Lift LPT Using Acoustic Forcing
Authors: Bernardini Chiara , Benton Stuart , Chen Jen-Ping , Bons Jeffrey P.
Published: November 2013

The mechanism of separation control by sound excitation is investigated on the aft loaded LPT blade profile, the L1A, which experiences a large boundary layer separation at low Reynolds numbers. Previous work by the authors has shown that on a laminar separation bubble such as that experienced by the front-loaded L2F profile, sound excitation control has its best performance at the most unstable frequency of the shear layer due to the exploitation of the linear instability mechanism. The different loading distribution on the L1A increases the distance of the separated shear layer from the wall and the exploitation of the same linear mechanism is no longer effective in these conditions. However, significant control authority is found in the range of the first subharmonic of the natural unstable frequency. The amplitude of forced excitation required for significant wake loss reduction is higher than that needed when exploiting linear instability, but unlike the latter case, no threshold amplitude is found. The fluid-dynamics mechanisms under these conditions are investigated by PIV measurements. Phase-locked PIV data gives insight into the growth and development of structures as they are shed from the shear layer and merge to lock into the excited frequency. Unlike near-wall laminar separation sound control, it is found that when such large separated shear layers occur, sound excitation at subharmonics of the fundamental frequency is still effective with high Tu levels.
On the Influence of Fuel Distribution on the Flame Structure of Bluff-Body Stabilized Flames
Authors: Lovett Jeffery A. , Ahmed Kareem A. , Bibik Oleksandr , Smith Andrew G. , Lubarsky Eugene , Menon Suresh , Zinn Ben T.
Published: November 2013

This paper describes recent learning on the flame structure associated with bluff-body stabilized flames and the influence of the fuel distribution with nonpremixed, jet-in-crossflow fuel injection. Recent experimental and analytical results disclosing the flame structure are discussed in relation to classical combustion reaction zone regimes. Chemiluminescence and planar fluorescence imaging of OH* radicals as an indicator of the flame zone are analyzed from various tests conducted at Georgia Tech using a two-dimensional vane-type bluffbody with simple wall-orifice fuel injectors. The results described in this paper support the view that combustion occurs in separated flame zones aligned with the non-premixed fuel distribution associated with the fuel jets that are very stable and contribute to flame stability at low fuel flow rates. The experimental data is also compared with computational reacting flow large-eddy simulations and interpreted in terms of the fundamental reaction zone regimes for premixed flames. For the conditions of the present experiment, the results indicate combustion occurs over a wide range of flame regimes including the broken reaction zone or separated flamelet regimes.
Performance Prediction of Gas Turbine Under Different Strategies Using Low Heating Value Fuel
Authors: da Silva Edson Batista , Assato Marcelo , de Lima Rosiane Cristina
Published: November 2013

Usually, the turbogenerators are designed to fire a specific fuel, depending on the project of these engines may be allowed the operation with other kinds of fuel compositions. However, it is necessary a careful evaluation of the operational behavior and performance of them due to conversion, for example, from natural gas to different low heating value fuels. Thus, this work describes strategies used to simulate the performance of a single shaft industrial gas turbine designed to operate with natural gas when firing low heating value fuel, such as biomass fuel from gasification process or blast furnace gas (BFG). Air bled from the compressor and variable compressor geometry have been used as key strategies by this paper. Off-design performance simulations at a variety of ambient temperature conditions are described. It was observed the necessity for recovering the surge margin; both techniques showed good solutions to achieve the same level of safe operation in relation to the original engine. Finally, a flammability limit analysis in terms of the equivalence ratio was done. This analysis has the objective of verifying if the combustor will operate using the low heating value fuel. For the most engine operation cases investigated, the values were inside from minimum and maximum equivalence ratio range.
Effect of Mode of Operation on Gas Turbine Combustor Performance
Authors: Mohammad Bassam S. , McManus Keith , Vandervort Christian , Goldmeer Jeffrey , Symonds Richard
Published: November 2013

The primary goal of this study is to quantify the differences in combustor performance under different modes of operation as a function of the combustor exit temperature. The main focus is the effect on liner heat loading since liner durability is strongly dependent on the metal peak temperature as well as temperature gradients. The study also includes the effect on emissions and acoustics. Three modes of operation are discussed: non premixed natural gas operation, dry liquid fuel operation and wet liquid fuel. Limited, premixed, natural gas data are also discussed when appropriate. Experiments are conducted on a Single Nozzle Rig (SNR) at conditions representative of different power levels of F class gas turbines. The results are analyzed to show the natural gas vs. dry liquid fuel performance, followed by the effect of water injection and effect of load variation. The results show that heat loading impact is amplified in the head end region since this is where the flame stabilizes. The combustor head end average temperature is 55.6 K (100 F) higher for dry fuel oil when compared to natural gas. However, the tail section of the liner is 25.3 K (50 F) lower for fuel oil. The difference is mainly attributed to the change in flame shape and flame radiation. CO emissions were roughly 80 ppm lower for natural gas. NOx is higher for liquid fuel (35–80% depending on flame temperature). Emissions profiles at the combustor exit are similar for both fuels with a variability of 40% indicating [the profile] is controlled by flow-flame interaction. Acoustics are lower in amplitude for non-premixed natural gas, but peak frequency is similar. Liquid fuel wet mode of operation results in significant reduction in the head end temperature due to the water impingement on the liner 166.8 K (∼300F). However, the maximum temperature over the tail section is 25.3 K (50F) higher than dry operation. Yet, the average tail temperature is similar under both modes of operation with higher variability under wet operation (70%). This strong temperature variability can influence the liner life. More than 80% reduction in NOx emissions is achieved with water injection. Water injection impact on CO is dictated by CO generation mode (quenching vs. dissociation). More important is the significant improvement in emissions profile at the combustor exit with water injection (60% reduction in variability). At higher load, the maximum liner temperature is 44.5–83.5 K (80–150 F) higher than part load. This is mainly attributed to the increase in air inlet temperature and increase in radiation heat flux which is dependent on both flame temperature and pressure. More investigations are required to determine the impact on complicated engine configurations as well as to isolate the effect of flame shape.
Effects of Combustor Exit Temperature Profile on Adiabatic Effectiveness of Leakage Flow Film Cooling Over an Axisymmetric Endwall
Authors: Seah Yuh Yen , Erickson Ryan , Simon Terrence , Moon Hee-Koo , Zhang Luzeng
Published: November 2013

The effects of a representative combustor exit temperature profile on leakage flow film cooling effectiveness were experimentally documented. This was done in a stationary, linear blade row cascade with an axisymmetric blade platform of dolphin-nose-shape. Endwall adiabatic film cooling effectiveness distributions and near-endwall passage thermal fields are documented. Results from the case with a representative combustor exit temperature profile are compared to those with other combustor exit temperature profiles including a base case with a uniform temperature distribution. All cases were done in the same facility over a range of disk cavity leakage flow rates. This study quantifies the sensitivity of endwall film cooling due to coolant in the leakage flow and in the approach flow to the shape of the combustor exit temperature profile. The results indicate that leakage flow film cooling effectiveness is significantly lower with a well-mixed (uniform temperature) combustor exit temperature profile than in cases in which the combustor exit temperature distribution is strongly variable. That is, it is demonstrated that combustor cooling flow aids endwall protection considerably. It is also shown that leakage flow has only a mild influence over the endwall cooling that can be attributed to coolant in the approach flow.
Iron(IV)hydroxide p
K
a
and the Role of Thiolate Ligation in C–H Bond Activation by Cytochrome P450
Authors: Yosca Timothy H. , Rittle Jonathan , Krest Courtney M. , Onderko Elizabeth L. , Silakov Alexey , Calixto Julio C. , Behan Rachel K. , Green Michael T.
Published: November 2013

The p
K
a
of P450

Cytochrome P450 enzymes oxidize hydrocarbons through activation of oxygen at heme iron centers. However, the protein backbone has various sites (particularly tyrosine residues) that are also sensitive to oxidation, so how can the enzyme rapidly transform substrates without attacking itself?

Yosca
et al.

(p.
825
) explored the energetics of the competition between substrate and self-oxidation by measuring the p
K
a
of the enzyme's iron(IV)hydroxide motif. Cysteine thiolate coordination to iron in the P450 structure raised the p
K
a
almost to 12—rendering the iron oxo far more basic than analogous motifs in other heme environments. Correspondingly, the electronic environment for H-atom transfer from the substrate was relatively favorable, compared to electron transfer from a backbone residue.
Hint of Dark Matter May Be Just Cosmic Ray Debris
Authors: Cho Adrian
Published: November 2013

Researchers hoped an unexpected surplus of positrons measured in space would reveal the particles behind dark matter, but new work shows the purported excess simply might not exist.
A Putative Antiaging Drug Takes a Step From Mice to Men
Authors: Leslie Mitch
Published: November 2013

A new clinical trial is gauging whether rapamycin, a drug that increases longevity in mice, alleviates infirmities of old age in people.
Toll-Like Receptor 2 in Serum: a Potential Diagnostic Marker of Prosthetic Joint Infection?
Authors: Galliera Emanuela , Drago Lorenzo , Vassena Christian , Romanò Carlo , Gioia Marazzi Monica , Salcito Lucia , Corsi Romanelli Massimiliano M.
Published: November 2013

Prosthetic joint infection (PJI) is a severe complication of arthroplasty and is still lacking diagnostic gold standards. PJI patients display high Toll-like receptor 2 (TLR2) serum levels, correlating with canonical inflammatory markers (C-reactive protein [CRP], interleukin 6 [IL-6], tumor necrosis factor alpha [TNF-α], and IL-1). Therefore, TLR2 serum levels could be considered a new potential diagnostic tool in the early detection of PJI.
Comparative Analysis of Hepatitis B Virus Polymerase Sequences Required for Viral RNA Binding, RNA Packaging, and Protein Priming
Authors: Jones Scott A. , Clark Daniel N. , Cao Feng , Tavis John E. , Hu Jianming
Published: November 2013

Hepatitis B virus replicates a DNA genome through reverse transcription of a pregenomic RNA (pgRNA) by using a multifunctional polymerase (HP). A critical function of HP is its specific association with a viral RNA signal, termed ε (Hε), located on pgRNA, which is required for specific packaging of pgRNA into viral nucleocapsids and initiation of viral reverse transcription. HP initiates reverse transcription by using itself as a protein primer (protein priming) and Hε as the obligatory template. HP is made up of four domains, including the terminal protein (TP), the spacer, the reverse transcriptase (RT), and the RNase H domains. A recently developed, Hε-dependent,
in vitro
protein priming assay was used in this study to demonstrate that almost the entire TP and RT domains and most of the RNase H domain were required for protein priming. Specific residues within TP, RT, and the spacer were identified as being critical for HP-Hε binding and/or protein priming. Comparison of HP sequence requirements for Hε binding, pgRNA packaging, and protein priming allowed the classification of the HP mutants into five groups, each with distinct effects on these complex and related processes. Detailed characterization of HP requirements for these related and essential functions of HP will further elucidate the mechanisms of its multiple functions and aid in the targeting of these functions for antiviral therapy.
Processing of the L1 52/55k Protein by the Adenovirus Protease: a New Substrate and New Insights into Virion Maturation
Authors: Pérez-Berná Ana J. , Mangel Walter F. , McGrath William J. , Graziano Vito , Flint Jane , San Martín Carmen
Published: November 2013

Late in adenovirus assembly, the viral protease (AVP) becomes activated and cleaves multiple copies of three capsid and three core proteins. Proteolytic maturation is an absolute requirement to render the viral particle infectious. We show here that the L1 52/55k protein, which is present in empty capsids but not in mature virions and is required for genome packaging, is the seventh substrate for AVP. A new estimate on its copy number indicates that there are about 50 molecules of the L1 52/55k protein in the immature virus particle. Using a quasi-
in vivo
situation, i.e., the addition of recombinant AVP to mildly disrupted immature virus particles, we show that cleavage of L1 52/55k is DNA dependent, as is the cleavage of the other viral precursor proteins, and occurs at multiple sites, many not conforming to AVP consensus cleavage sites. Proteolytic processing of L1 52/55k disrupts its interactions with other capsid and core proteins, providing a mechanism for its removal during viral maturation. Our results support a model in which the role of L1 52/55k protein during assembly consists in tethering the viral core to the icosahedral shell and in which maturation proceeds simultaneously with packaging, before the viral particle is sealed.
Equine Tetherin Blocks Retrovirus Release and Its Activity Is Antagonized by Equine Infectious Anemia Virus Envelope Protein
Authors: Yin Xin , Hu Zhe , Gu Qinyong , Wu Xingliang , Zheng Yong-Hui , Wei Ping , Wang Xiaojun
Published: November 2013

Human tetherin is a host restriction factor that inhibits replication of enveloped viruses by blocking viral release. Tetherin has an unusual topology that includes an N-terminal cytoplasmic tail, a single transmembrane domain, an extracellular domain, and a C-terminal glycosylphosphatidylinositol anchor. Tetherin is not well conserved across species, so it inhibits viral replication in a species-specific manner. Thus, studies of tetherin activities from different species provide an important tool for understanding its antiviral mechanism. Here, we report cloning of equine tetherin and characterization of its antiviral activity. Equine tetherin shares 53%, 40%, 36%, and 34% amino acid sequence identity with feline, human, simian, and murine tetherins, respectively. Like the feline tetherin, equine tetherin has a shorter N-terminal domain than human tetherin. Equine tetherin is localized on the cell surface and strongly blocks human immunodeficiency virus type 1 (HIV-1), simian immunodeficiency virus (SIV), and equine infectious anemia virus (EIAV) release from virus-producing cells. The antiviral activity of equine tetherin is neutralized by EIAV envelope protein, but not by the HIV-1 accessory protein Vpu, which is a human tetherin antagonist, and EIAV envelope protein does not counteract human tetherin. These results shed new light on our understanding of the species-specific tetherin antiviral mechanism.
Postcaesarean open-heart surgery forStreptococcus sanguinisinfective endocarditis
Authors: Kongwattanakul Kiattisak , Tribuddharat Sirirat , Prathanee Sompop , Pachirat Orathai
Published: November 2013

A 33-week pregnant (gravida 3), 29-year-old woman was transferred for management ofStreptococcus sanguinisinfective endocarditis. A vegetation was present on the posterior leaflet of the mitral valve with moderate mitral regurgitation. On admission (day 1), the ultrasound examination revealed splenic abscesses and retarded intrauterine growth albeit with normal vessels. The fetal heart rate was 140 bpm. On day 11, the baby was delivered by Caesarean, and then the mother underwent tubal ligation followed by a mitral valve repair. The splenic abscess was treated with antibiotics. The woman was clinically stable and recovered uneventfully. This successful outcome was achieved by a strategic (optimal and sequential) timeline for selecting the mode of delivery and type of mitral valve correction.
Intermediate vaginal flora and bacterial vaginosis are associated with the same factors: findings from an exploratory analysis among female sex workers in Africa and India
Authors: Guédou Fernand A , Van Damme Lut , Deese Jennifer , Crucitti Tania , Mirembe Florence , Solomon Suniti , Becker Marissa , Alary Michel
Published: November 2013

Objectives

Several recent studies suggest that intermediate vaginal flora (IVF) is associated with similar adverse health outcomes as bacterial vaginosis (BV). Yet, it is still unknown if IVF and BV share the same correlates. We conducted a cross-sectional and exploratory analysis of data from women screened prior to enrolment in a microbicide trial to estimate BV and IVF prevalence and examine their respective correlates.

Methods

Participants were interviewed, examined and provided blood and genital samples for the diagnosis of IVF and BV (using Nugent score) and other reproductive tract infections. Polytomous logistic regressions were used in estimating respective ORs of IVF and BV, in relation to each potential risk factor.

Results

Among 1367 women, BV and IVF prevalences were 47.6% (95% CI 45.0% to 50.3%) and 19.2% (95% CI 17.1% to 21.2%), respectively. Multivariate polytomous analysis of IVF and BV showed that they were generally associated with the same factors. The respective adjusted ORs were for HIV 1.98 (95% CI 1.37 to 2.86) and 1.62 (95% CI 1.20 to 2.20) (p=0.2248), for gonorrhoea 1.25 (95% CI 0.64 to 2.4) and 2.01 (95% CI 1.19 to 3.49) (p=0.0906), for trichomoniasis 3.26 (95% CI 1.71 to 6.31) and 2.39 (95% CI 1.37 to 4.33) (p=0.2630), for candidiasis 0.52 (95% CI 0.36 to 0.75) and 0.59 (95% CI 0.44 to 0.78) (p=0.5288), and for hormonal contraception 0.65 (95% CI 0.40 to 1.04) and 0.62 (95% CI 0.43 to 0.90) (p=0.8819). In addition, the association between vaginal flora abnormalities and factors such as younger age, HIV, gonorrhoea trichomoniasis and candidiasis were modified by the study site (all p for interaction ≤0.05).

Conclusions

IVF has almost the same correlates as BV. The relationship between some factors and vaginal flora abnormalities may be site-specific.
The Flin Flon paleosol revisited
Authors: Babechuk Michael G. , Kamber Balz S.
Published: November 2013

A ca. 1.85 Ga paleosol developed on seafloor-altered mafic rocks is preserved beneath continental sandstones and conglomerates of the Missi Group near Flin Flon, Manitoba. Previous work has focused on a locality where the paleosol is developed on pillowed greenstone (chlorite + albite + epidote + calcite + quartz + Fe–Ti oxides ± mica). This area has been revisited and a new (∼5 m) profile was excavated and sampled at a very high density for geochemical (major element; ∼60 samples) and mineralogical (petrography, X-ray diffraction) investigation. The high sampling density has revealed a relatively sharp immobile-element offset (e.g., Al/Ti) in the profile. This could reflect weathering across two separate parent rocks or preferential addition of allochthonous material into the top of the profile. Regardless, comparison with a wide suite of volcanic rocks in the stratigraphy suggests that the original concentration of Fe and probably also Ca and Mg in the greenstone on either side of the boundary was similar, permitting quantitative treatment of major-element trends. The profile shows pronounced upward loss of Ca, Mg, Mn2+, and Fe2+and a corresponding increase in Al, Ti, and total Fe. Physical weathering features, such as corestones, are well preserved and show progressive alteration upwards in the profile in parallel with the chemical trends. Deep in the profile, Na and Ca are lower than the greenstone due to the weathering of albite and epidote, whereas Mg, Fe, and Mn were largely retained in chlorite and secondary dolomite. Upwards in the profile, the loss of chlorite and dolomite and the increase of illite – mixed-layer clays and white mica (probably 2:1 layer or mixed-layer clays originally) and hematite are accompanied by a transition from green to maroon colour. Above a well-defined depth in the profile, carbonate is virtually absent, and the paleosol is highly depleted in Ca. This transition in the paleosol coincides with the immobile-element offset. The significance of this coincidence remains to be explored. Reworking of regolith (e.g., rip-up clasts) occurred during deposition of the Missi sediments, and burial and subsequent metamorphism resulted in the upward enrichment of K and Na and the associated conversion of pedogenic clays to illite and micas (muscovite and paragonite). Crosscutting quartz and epidote veins and tourmaline formation near the unconformity contact implies minor post-burial fluid movement. Despite these complexities, there is consistent retention of Fe through formation of pedogenic Fe oxides, attested by the near-constant ∑Fe/Al ratio in the profile. There is very little evidence for subsequent Fe reduction by hydrothermal or organic fluids. Instead, trends in the Fe speciation are controlled predominantly by the modal variation of Fe–Ti oxides in the greenstone and spheroidal weathering textures in the paleosol.
Do metaboreceptors alter heat loss responses following dynamic exercise?
Authors: McGinn Ryan , Swift Brendan , Binder Konrad , Gagnon Daniel , Kenny Glen P.
Published: November 2013

Metaboreceptor activation during passive heating is known to influence cutaneous vascular conductance (CVC) and sweat rate (SR). However, whether metaboreceptors modulate the suppression of heat loss following dynamic exercise remains unclear. On separate days, before and after 15 min of high-intensity treadmill running in the heat (35°C), eight males underwent either 1) no isometric handgrip exercise (IHG) or ischemia (CON), 2) 1 min IHG (60% of maximum, IHG), 3) 1 min IHG followed by 2 min of ischemia (IHG+OCC), 4) 2 min of ischemia (OCC), or 5) 1 min IHG followed by 2 min of ischemia with application of lower body negative pressure (IHG+LBNP). SR (ventilated capsule), cutaneous blood flow (Laser-Doppler), and mean arterial pressure (Finometer) were measured continuously before and after dynamic exercise. Following dynamic exercise, CVC was reduced with IHG exercise ( P < 0.05) and remained attenuated with post-IHG ischemia during IHG+OCC relative to CON (39 ± 2 vs. 47 ± 6%, P < 0.05). Furthermore, the reduction in CVC was exacerbated by application of LBNP during post-IHG ischemia (35 ± 3%, P < 0.05) relative to IHG+OCC. SR increased during IHG exercise ( P < 0.05) and remained elevated during post-IHG ischemia relative to CON following dynamic exercise (0.94 ± 0.15 vs. 0.53 ± 0.09 mg·min−1·cm−2, P < 0.05). In contrast, application of LBNP during post-IHG ischemia had no effect on SR (0.93 ± 0.09 mg·min−1·cm−2, P > 0.05) relative to post-IHG ischemia during IHG+OCC. We show that CVC is reduced and that SR is increased by metaboreceptor activation following dynamic exercise. In addition, we show that the metaboreflex-induced loading of the baroreceptors can influence the CVC response, but not the sweating response.
Differential requirement for NMDAR activity in SAP97β-mediated regulation of the number and strength of glutamatergic AMPAR-containing synapses
Authors: Liu Mingna , Lewis Laura D. , Shi Rebecca , Brown Emery N. , Xu Weifeng
Published: November 2013

PSD-95-like, disc-large (DLG) family membrane-associated guanylate kinase proteins (PSD/DLG-MAGUKs) are essential for regulating synaptic AMPA receptor (AMPAR) function and activity-dependent trafficking of AMPARs. Using a molecular replacement strategy to replace endogenous PSD-95 with SAP97β, we show that the prototypic β-isoform of the PSD-MAGUKs, SAP97β, has distinct NMDA receptor (NMDAR)-dependent roles in regulating basic properties of AMPAR-containing synapses. SAP97β enhances the number of AMPAR-containing synapses in an NMDAR-dependent manner, whereas its effect on the size of unitary synaptic response is not fully dependent on NMDAR activity. These effects contrast with those of PSD-95α, which increases both the number of AMPAR-containing synapses and the size of unitary synaptic responses, with or without NMDAR activity. Our results suggest that SAP97β regulates synaptic AMPAR content by increasing surface expression of GluA1-containing AMPARs, whereas PSD-95α enhances synaptic AMPAR content presumably by increasing the synaptic scaffold capacity for synaptic AMPARs. Our approach delineates discrete effects of different PSD-MAGUKs on principal properties of glutamatergic synaptic transmission. Our results suggest that the molecular diversity of PSD-MAGUKs can provide rich molecular substrates for differential regulation of glutamatergic synapses in the brain.
Cortical regulation of dopaminergic neurons: role of the midbrain superior colliculus
Authors: Bertram C. , Dahan L. , Boorman L. W. , Harris S. , Vautrelle N. , Leriche M. , Redgrave P. , Overton P. G.
Published: November 2013

Dopaminergic (DA) neurons respond to stimuli in a wide range of modalities, although the origin of the afferent sensory signals has only recently begun to emerge. In the case of vision, an important source of short-latency sensory information seems to be the midbrain superior colliculus (SC). However, longer-latency responses have been identified that are less compatible with the primitive perceptual capacities of the colliculus. Rather, they seem more in keeping with the processing capabilities of the cortex. Given that there are robust projections from the cortex to the SC, we examined whether cortical information could reach DA neurons via a relay in the colliculus. The somatosensory barrel cortex was stimulated electrically in the anesthetized rat with either single pulses or pulse trains. Although single pulses produced small phasic activations in the colliculus, they did not elicit responses in the majority of DA neurons. However, after disinhibitory intracollicular injections of the GABAA antagonist bicuculline, collicular responses were substantially enhanced and previously unresponsive DA neurons now exhibited phasic excitations or inhibitions. Pulse trains applied to the cortex led to phasic changes (excitations to inhibitions) in the activity of DA neurons at baseline. These were blocked or attenuated by intracollicular administration of the GABAA agonist muscimol. Taken together, the results indicate that the cortex can communicate with DA neurons via a relay in the SC. As a consequence, DA neuronal activity reflecting the unexpected occurrence of salient events and that signaling more complex stimulus properties may have a common origin.
Random Response Forest for Privacy-Preserving Classification
Authors: Szűcs Gábor
Published: November 2013

The paper deals with classification in privacy-preserving data mining. An algorithm, the Random Response Forest, is introduced constructing many binary decision trees, as an extension of Random Forest for privacy-preserving problems. Random Response Forest uses the Random Response idea among the anonymization methods, which instead of generalization keeps the original data, but mixes them. An anonymity metric is defined for undistinguishability of two mixed sets of data. This metric, the binary anonymity, is investigated and taken into consideration for optimal coding of the binary variables. The accuracy of Random Response Forest is presented at the end of the paper.
CFD Analysis of Energy Separation in Ranque-Hilsch Vortex Tube at Cryogenic Temperature
Authors: Dutta T. , Sinhamahapatra K. P. , Bandyopadhyay S. S.
Published: November 2013

Study of the energy separation phenomenon in vortex tube (VT) at cryogenic temperature (temperature range below 123 K) has become important because of the potential application of VT as in-flight air separator in air breathing propulsion. In the present study, a CFD model is used to simulate the energy separation phenomenon in VT with gaseous air at cryogenic temperature as working fluid. Energy separation at cryogenic temperature is found to be considerably less than that obtained at normal atmospheric temperature due to lower values of inlet enthalpy and velocity. Transfer of tangential shear work from inner to outer fluid layers is found to be the cause of energy separation. A parametric sensitivity analysis is carried out in order to optimize the energy separation at cryogenic temperature. Also, rates of energy transfer in the form of sensible heat and shear work in radial and axial directions are calculated to investigate the possible explanation of the variation of the hot and cold outlet temperatures with respect to various geometric and physical input parameters.
Predictive Value of Admission N-Terminal Pro-B-Type Natriuretic Peptide and Renal Function in Older People Hospitalized for Dyspnoea
Authors: Fabbian Fabio , De Giorgi Alfredo , Pala Marco , Volpato Stefano , Portaluppi Francesco , Zuliani Giovanni , Manfredini Roberto
Published: November 2013

Background. We investigated the relationship between NT-pro-BNP, glomerular filtration rate (GFR), and all-cause mortality rates in a cohort of older people discharged from an internal medicine unit after admission for dyspnoea.Patients and Methods. NT-pro-BNP was evaluated in serum samples of 134 patients aged 80 ± 6 years who presented to a single academic centre with worsening dyspnoea. History data and anthropometric, clinical, and biochemical parameters including GFR were collected at the time of admission. 119 out of 134 were discharged alive from hospital and were included in the follow-up of 779 ± 370 days.Results. 35 out of 119 subjects died after a follow-up of 266 ± 251 days. Cox proportional hazards model showed that GFR and Ln (NT-pro-BNP) were predictors for all-cause mortality with estimated hazard ratios of 0.969 (95% confidence interval: 0.950–0.988;P=0.001) and 2.360 (95% confidence interval: 1.208–4.610;P=0.012), respectively. Patients characterized by high NT-pro-BNP levels and GFR ≥ 60 mL/min/1.73 m2showed a dramatic reduction in survival duration compared with the groups with different combinations of the two variables (P=0.008).Conclusions. In the elderly, NT-pro-BNP and GFR are predictors of all-cause mortality after admission because of dyspnoea. Since the fact that subjects with high NT-pro-BNP and GFR≥60 mL/min/1.73 m2exhibited a reduced survival, high admission NT-pro-BNP suggests future negative outcome.
Trends in the Incidence of Childhood Type 1 Diabetes Mellitus in Beijing Based on Hospitalization Data from 1995 to 2010
Authors: Gong Chunxiu , Meng Xi , Saenger Paul , Wu Dongning , Cao Bingyan , Wu Di , Wei Liya
Published: November 2013

Objectives: To study the incidence trend of type 1 diabetes mellitus (T1DM) in children in Beijing from 1995 to 2010, to compare it with incidences reported worldwide and to predict the requirement of medical resources in the future. Methods: This study involved newly diagnosed T1DM cases younger than 15 years of age in the Beijing Children's Hospital from January 1995 to December 2010. We calculated the incidence of T1DM children in Beijing according to hospitalization data and Beijing's population. We defined it as the underestimated incidence rate (UE-IR). Results: The UE-IRs of T1DM ranged from around 0.88/100,000 to 2.37/100,000 for children in Beijing younger than 15 years of age from 1995 to 2010. The UE-IR increased faster in boys (1.47 times) and in the age group of 0-4 years (1.89 times) after 2003. The UE-IR was greatest in children aged 5-9 years (1.81/100,000) followed by the age of puberty (10-14 years, 1.76/100,000). The predicted number of new T1DM cases in Beijing will increase 1.97 times over the next 10 years. Conclusions: The incidence trend of T1DM was increasing gradually in those younger than 15 years of age in Beijing. The incidence of younger children and boys grew faster. The 5- to 14-year-old children represented a high-risk population of T1DM. The number of predicted new T1DM cases will grow rapidly. This means that we should train more health care providers for pediatric diabetes patients, in order to achieve high-quality medical care and to be able to prevent or postpone chronic complications.
Histological Evaluation to Study the Effects of Dental Amalgam and Composite Restoration on Human Dental Pulp: An in vivo Study
Authors: Chandwani Neelam D. , Pawar Mansing G. , Tupkari Jagdish V. , Yuwanati Monal
Published: November 2013

Objective: To study and compare the effects of dental amalgam and composite restorations on human dental pulp. Materials and Methods: One hundred sound premolars scheduled for orthodontic extraction were divided equally into two groups: group A, teeth restored with silver amalgam, and group B, teeth restored with composite resin. Each group was equally subdivided into two subgroups [extracted after 24 h (A-1 and B-1) or 7 days (A-2 and B-2)], and the histological changes in the pulp related to the two different materials at the two different intervals were studied. Results: It was found that after 24 h, the inflammatory response of the pulp in teeth restored with amalgam and composite was similar (p = 1.00). However, after 7 days, the severity of the inflammatory response of the pulp in teeth restored with amalgam was less compared to that in teeth restored with composite (p = 0.045). Conclusion: This study confirmed that amalgam continues to be the mechanically as well as biologically more competent restorative material. Composite could be a promising restorative material to satisfy esthetic needs for a considerable period of time. However, its biological acceptance is still in doubt.
Height Gain in Ullrich-Turner Syndrome after Early and Late Growth Hormone Treatment Start: Results from a Large Retrospective German Study and Potential Basis for an Individualized Treatment Approach
Authors: Bettendorf Markus , Inta Ioana M. , Doerr Helmuth G. , Hauffa Berthold P. , Mehls Otto , Ranke Michael B.
Published: November 2013

Background: Ullrich-Turner syndrome (UTS) girls often present with short stature in adolescence to the endocrinologist when the efficacy of growth hormone (GH) to improve growth remains unknown and parameters to estimate individual GH responsiveness have yet to be determined. Objective: Retrospective evaluation of adult height (AH) and predicted adult height at GH start (descriptive model of Ranke, Model PredAH) in early and late GH-treated German UTS patients. Subjects/Methods: 313 patients treated with GH, early [chronological age (CA) at GH start <12 years, n = 259] or late (CA at GH start ≥12 years, n = 54) who reached AH were selected from KIGS (Pfizer International Growth Database). Results: AH (152.5 ± 5.9 vs. 151.1 ± 5.4 cm, p = n.s.) after GH treatment for 7.5 ± 2.12 years (GH start early) and for 5.2 ± 1.2 years (GH start late) were similar (p = n.s.) as Model PredAH (155.7 ± 4.8 vs. 154.7 ± 4.8 cm; p = n.s.) but higher (p < 0.001) than projected adult height (Ranke, ProjAH; 148.2 ± 5.5 vs. 145.2 ± 6.7 cm; p = 0.001). Total height gain over ProjAH was 4.3 ± 4.6 cm (GH start early) and 5.8 ± 4.7 cm (GH start late, p = 0.021), respectively. Conclusions: GH may improve AH in UTS patients even when started late. The individual growth response could be estimated by the descriptive Model PredAH independent of age at treatment start.