bluuebunny/crossref_metadata_2025 huggingface dataset:
Variational Method in Limit Load Analysis—A Review
Authors: Adibi-Asl Reza , Seshadri R.
Published: August 2018

This paper reviews the literature on variational method in limit load analysis and presents both analytical and numerical approaches. One of the most successful applications of variational method in theory of plasticity is limit load analysis. The main objective of the limit load analysis is to estimate the load at the impending plastic limit state of a body. However, for complicated problems it may be very difficult to find the exact limit load. Therefore, based on the extremum principles of limit load analysis, the lower-bound theorem or the upper bound theorem is employed to estimate the limit load directly without considering the entire loading history. In general, limit load analysis plays an important role in design and fitness-for-service assessment of pressurized vessels and piping.
Drift-Flux Correlation of Oil–Water Flow in Horizontal Channels
Authors: Baotong Somchai , Rassame Somboon , Nilsuwankosit Sunchai , Hibiki Takashi
Published: August 2018

An accurate and practical approach is necessary for predicting oil fraction in horizontal oil–water flows. In this study, a concept of a drift-flux model is adopted to develop a predictive method for the oil fraction in the horizontal oil–water flows due to its simplicity and practicality. A new drift-flux correlation for the horizontal oil–water flows is developed based on the least square method using collected experimental data. The distribution parameter is determined to be 1.05 for the data with the ratio of oil density to water density ranging from 0.787 to 1.00, whereas the oil fraction weighted mean drift velocity is set at 0 m/s due to the flow direction perpendicular to the gravity direction. The physical meaning for the order of unity of the distribution parameter is explained by introducing a simple model. The predictive capability of the new drift-flux correlation is examined using the collected database of oil–water flows in horizontal pipes under a variety of test conditions. It is demonstrated that the new drift-flux correlation can predict the existing oil fractions in the horizontal pipe channels with the mean absolute error, standard deviation, mean relative deviation, and mean absolute relative deviation being −0.0124, 0.0338, −3.25%, and 9.57%, respectively.
Blowoff and Reattachment Dynamics of a Linear Multinozzle Combustor
Authors: Kwong Wing Yin , Steinberg Adam M.
Published: August 2018

This paper describes the coupled flow and flame dynamics during blowoff and reattachment events in a combustor consisting of a linear array of five interacting nozzles using 10 kHz repetition-rate OH planar laser-induced fluorescence and stereoscopic particle image velocimetry (S-PIV). Steady operating conditions were studied at which the three central flames randomly blew-off and subsequently reattached to the bluff-bodies. Transition of the flame from one nozzle was rapidly followed by transition of the other nozzles, indicating cross-nozzle coupling. Blow-off transitions were preferentially initiated in one of the off-center nozzles, with the transition of subsequent nozzles occurring in a random order. Similarly, the center nozzle tended to be the last nozzle to reattach. The blow-off process of any individual nozzle was similar to that for a single bluff-body stabilized flame, though with cross-flame interactions providing additional means of restabilizing a partially extinguished flame. Subsequent to blowoff of the first nozzle, the other nozzles underwent similar blow-off processes. Flame reattachment was initiated by entrainment of a burning pocket into a recirculation zone, followed by transport to the bluff-body; the other nozzles subsequently underwent similar reattachment processes. Several forms of cross-nozzle interaction that can promote or prevent transition are identified. Furthermore, the velocity measurements indicated that blowoff or reattachment of the first nozzle during a multinozzle transition causes significant changes to the flow fields of the other nozzles. It is proposed that a single-nozzle transition redistributes the flow to the other nozzles in a manner that promotes their transition.
Reduced-Order Modeling of Bladed Disks Considering Small Mistuning of the Disk Sectors
Authors: Schwerdt Lukas , Willeke Sebastian , Scheidt Lars Panning-von , Wallaschek Jörg
Published: August 2018

A model order reduction method based on the component mode synthesis for mistuned bladed disks is introduced, with one component for the disk and one component for each blade. The interface between the components at the blade roots is reduced using the wave-based substructuring (WBS) method, which employs tuned system modes. These system modes are calculated first, and used subsequently during the reduction of the individual components, which eliminates the need to build a partially reduced intermediate model with dense matrices. For the disk, a cyclic Craig–Bampton (CB) reduction is applied. The deviations of the stiffness and mass matrices of individual disk sectors are then projected into the cyclic basis of interior and interface modes of the disk substructure. Thereby, it is possible to model small disk mistuning in addition to large mistuning of the blades.
Central Composite Experimental Design Applied to the Dry Sliding Wear Behavior of Mg/Mica Composites
Authors: John Iruthaya Raj M. , Manisekar K. , Gupta Manoj
Published: August 2018

A five-level four-factor central composite design multivariable model was constructed for the evaluation of the combined effect of operating parameters such as percentage reinforcement (0–10%), load (5–25 N), sliding speed (1–5 m/s), sliding distance (500–2500 m) on the wear rate of mica reinforced metal matrix composites. The microwave-assisted powder metallurgy technique was used to fabricate the composites. The wear tests were performed according to statistical designs to develop an empirical predictive regression model. The interaction of percentage reinforcement and sliding distance indicated the significant impact on wear rate. The statistical analysis confirms the optimum composition of mica blends leading to the best possible wear rate. No rapid wear region was identifiable in the morphology of worn composite surfaces.
Effect of Geometric Parameters on Mean Drop Sizes From Dual-Orifice Pressure Nozzles
Authors: Wei Xiao , Zhengyan Guo , Pimin Chen
Published: August 2018

Experimental studies have been conducted to investigate the effect of nozzle geometries on the atomization. Extensive measurements of mean drop size are conducted on the 15 dual-orifice pressure nozzles. These nozzles provide a range of discharge coefficient from 0.06 to 0.13. These experimental results are used to substantiate a semi-empirical correlation derived for determining the Sauter mean diameter (SMD) of sprays generated by dual-orifice pressure nozzles. The correlation is obtained by modeling the liquid internal and outer flow that govern the atomization process in dual-orifice pressure nozzles. A very satisfactory agreement is demonstrated between the predictions based on the correlations and the actual measured values of the SMD.
The Influence of an Upstream Pylon on Open Rotor Aerodynamics at Angle of Attack
Authors: Sohoni Nishad G. , Hall Cesare A. , Parry Anthony B.
Published: August 2018

The aerodynamic impact of installing a horizontal pylon in front of a contra-rotating open rotor engine, at take-off, was studied. The unsteady interactions of the pylon's wake and potential field with the rotor blades were predicted by full-annulus URANS CFD calculations at 0 deg and 12 deg angle of attack (AoA). Two pylon configurations were studied: one where the front rotor blades move down behind the pylon (DBP), and one where they move up behind the pylon (UBP). When operating at 12 deg AoA, the UBP orientation was shown to reduce the rear rotor tip vortex sizes and separated flow regions, whereas the front rotor wake and vortex sizes were increased. In contrast, the DBP orientation was found to reduce the incidence variations onto the front rotor, leading to smaller wakes and vortices. The engine flow was also time-averaged, and the variation in work done on average midspan streamlines was shown to depend strongly on variation in incidence, along with a smaller contribution related to change of radius.
A Proxy Model for Predicting SAGD Production From Reservoirs Containing Shale Barriers
Authors: Zheng Jingwen , Leung Juliana Y. , Sawatzky Ronald P. , Alvarez Jose M.
Published: August 2018

Artificial intelligence (AI) tools are used to explore the influence of shale barriers on steam-assisted gravity drainage (SAGD) production. The data are derived from synthetic SAGD reservoir simulations based on petrophysical properties and operational constraints gathered from the Suncor's Firebag project, which is representative of Athabasca oil sands reservoirs. The underlying reservoir simulation model is homogeneous and two-dimensional. Reservoir heterogeneities are modeled by superimposing sets of idealized shale barrier configurations on this homogeneous reservoir model. The individual shale barriers are categorized by their location relative to the SAGD well pair and by their geometry. SAGD production for a training set of shale barrier configurations was simulated. A network model based on AI tools was constructed to match the output of the reservoir simulation for this training set of shale barrier configurations, with a focus on the production rate and the steam-oil ratio (SOR). Then the trained AI proxy model was used to predict SAGD production profiles for arbitrary configurations of shale barriers. The predicted results were consistent with the results of the SAGD simulation model with the same shale barrier configurations. The results of this work demonstrate the capability and flexibility of the AI-based network model, and of the parametrization technique for representing the characteristics of the shale barriers, in capturing the effects of complex heterogeneities on SAGD production. It offers the significant potential of providing an indirect method for inferring the presence and distribution of heterogeneous reservoir features from SAGD field production data.
Growth Media Affects Microalgae Susceptibility to Disruption by Low-Frequency Power Ultrasound
Authors: Klinger Rory , Garoma Temesgen
Published: August 2018

The effect of microalgae growth medium on power ultrasound treatment of microalgal biomass was investigated. Chlorella vulgaris was grown in Bold's basal medium (BBM), Bristol's medium, sueoka medium, and MiracleGro All Purpose Water Soluble Plant Food. These media showed statistically indistinguishable intrinsic growth rates, averaging 0.052/day. Power ultrasound treatment was applied at 9.5 W for 5 min. MiracleGro showed chemical oxygen demand (COD) solvation post-sonication of 66%, twice that of other growth media per cell ruptured; which was unexpected based on observed consistent biomass quality. Media differences do not appear to have an effect on ultrasound power transfer; thus, C. vulgaris grown in MiracleGro medium has a decreased strength in terms of resistance to rupture by ultrasound. These results suggest that while biomass productivity and composition are important for the efficiency of extraction, media effects on the susceptibility of cells to pretreatment should not be ignored in overall process design.
On Analyzing the Optical Performance of Solar Central Tower Systems on Hillsides Using Biomimetic Spiral Distribution
Authors: Kiwan Suhil , Al Hamad Saif
Published: August 2018

The optical performance of solar central tower (CT) systems on hillsides of mountain areas is investigated based on the biomimetic spiral heliostat field distribution algorithm. The optical efficiencies and the field characteristics of different hillside solar field configurations are examined. The effect of various geometric parameters such as hillside tilt angle and the location of the receiver on the optical efficiency of the field are investigated and documented. The study is based on generating a 25 MWth power plant at the location of Sierra Sun Tower in California, USA, using Planta Solar 10 (PS10) heliostats' parameters. This study is performed numerically using a specially developed code using matlab software. The biomimetic spiral distribution pattern and the particle swarm optimization (PSO) method were used to obtain optimum solar fields. The spiral distribution shape factors were optimized for pursuing maximum annual weighted field efficiency. It is found that the annual optical weighted field efficiency for hillside solar fields is always lower than that for a flat field for same receiver height. On the other hand, the field land area for small hillside-slopes is smaller than that of a flat field area. It is found that there is an optimum field tilt angle where the land area is minimum. The minimum field area for the system studied in this paper was associated with (15 deg) field tilt angle. Furthermore, it was found that as the tower height increases the annual optical field weighted efficiency increases until it reaches a peak value. It was also found that, the closer the tower to the beginning of the heliostat field, the higher the field efficiency with less number of heliostats and less land area.
Optimization of the Taper/Twist Stacking Axis Location of NREL VI Wind Turbine Rotor Blade Using Neural Networks Based on Computational Fluid Dynamics Analyses
Authors: Kaya Mustafa , Elfarra Munir
Published: August 2018

The stacking axis locations for twist and taper distributions along the span of a wind turbine blade are optimized to maximize the rotor torque and/or to minimize the thrust. A neural networks (NN)-based model is trained for the torque and thrust values calculated using a computational fluid dynamics (CFD) solver. Once the model is obtained, constrained and unconstrained optimization is conducted. The constraints are the torque or the thrust values of the baseline turbine blade. The baseline blade is selected as the wind turbine blade used in the National Renewable Energy Laboratory (NREL) Phase VI rotor model. The Reynolds averaged Navier–Stokes (RANS) computations are done using the FINE/turbo flow solver developed by NUMECA International. The k-epsilon turbulence model is used to calculate the eddy viscosity. It is observed that achieving the same torque value as the baseline value is possible with about 5% less thrust. Similarly, the torque is increased by about 4.5% while maintaining the baseline thrust value.
Dissipative Kerr solitons in optical microresonators
Authors: Kippenberg Tobias J. , Gaeta Alexander L. , Lipson Michal , Gorodetsky Michael L.
Published: August 2018

Shrinking optical metrology

The ability to generate laser frequency combs—light sources comprising equidistant laser lines spanning a large range of wavelengths—has revolutionized metrology and precision spectroscopy. The past decade has seen frequency combs being generated in optical microresonator circuits, offering the prospect of shifting precision metrology applications from the realm of national laboratories to that of everyday devices. Kippenberg
et al.
review the development of microresonator-generated frequency combs and map out how understanding and control of their generation is providing a new basis for precision technology.

Science
, this issue p.
eaan8083
Slab2, a comprehensive subduction zone geometry model
Authors: Hayes Gavin P. , Moore Ginevra L. , Portner Daniel E. , Hearne Mike , Flamme Hanna , Furtney Maria , Smoczyk Gregory M.
Published: August 2018

Detailing subduction zones

Subduction zones are responsible for the most-damaging and tsunami-generating great earthquakes. Hayes
et al.
updated their Slab1.0 model to include all seismically active subduction zones, including geometrically complex regions like the Philippines. The new model, Slab2, details the geometry of 24 million square kilometers of subducted slabs, from ocean trench to upper mantle. The model will be vital for fully understanding seismic hazard in some of the most populated regions in the world.

Science
, this issue p.
58
Treatment of Infections by OXA-48-Producing Enterobacteriaceae
Authors: Stewart Adam , Harris Patrick , Henderson Andrew , Paterson David
Published: August 2018

Carbapenemase-producing
Enterobacteriaceae
(CPE) contribute significantly to the global public health threat of antimicrobial resistance. OXA-48 and its variants are unique carbapenemases with low-level hydrolytic activity toward carbapenems but no intrinsic activity against expanded-spectrum cephalosporins.
Developmental Dynamics of Long Noncoding RNA Expression during Sexual Fruiting Body Formation in Fusarium graminearum
Authors: Kim Wonyong , Miguel-Rojas Cristina , Wang Jie , Townsend Jeffrey P. , Trail Frances
Published: August 2018

Long noncoding RNA (lncRNA) plays important roles in sexual development in eukaryotes. In filamentous fungi, however, little is known about the expression and roles of lncRNAs during fruiting body formation. By profiling developmental transcriptomes during the life cycle of the plant-pathogenic fungus
Fusarium graminearum
, we identified 547 lncRNAs whose expression was highly dynamic, with about 40% peaking at the meiotic stage. Many lncRNAs were found to be antisense to mRNAs, forming 300 sense-antisense pairs. Although small RNAs were produced from these overlapping loci, antisense lncRNAs appeared not to be involved in gene silencing pathways. Genome-wide analysis of small RNA clusters identified many silenced loci at the meiotic stage. However, we found transcriptionally active small RNA clusters, many of which were associated with lncRNAs. Also, we observed that many antisense lncRNAs and their respective sense transcripts were induced in parallel as the fruiting bodies matured. The nonsense-mediated decay (NMD) pathway is known to determine the fates of lncRNAs as well as mRNAs. Thus, we analyzed mutants defective in NMD and identified a subset of lncRNAs that were induced during sexual development but suppressed by NMD during vegetative growth. These results highlight the developmental stage-specific nature and functional potential of lncRNA expression in shaping the fungal fruiting bodies and provide fundamental resources for studying sexual stage-induced lncRNAs.

IMPORTANCE
Fusarium graminearum
is the causal agent of the head blight on our major staple crops, wheat and corn. The fruiting body formation on the host plants is indispensable for the disease cycle and epidemics. Long noncoding RNA (lncRNA) molecules are emerging as key regulatory components for sexual development in animals and plants. To date, however, there is a paucity of information on the roles of lncRNAs in fungal fruiting body formation. Here we characterized hundreds of lncRNAs that exhibited developmental stage-specific expression patterns during fruiting body formation. Also, we discovered that many lncRNAs were induced in parallel with their overlapping transcripts on the opposite DNA strand during sexual development. Finally, we found a subset of lncRNAs that were regulated by an RNA surveillance system during vegetative growth. This research provides fundamental genomic resources that will spur further investigations on lncRNAs that may play important roles in shaping fungal fruiting bodies.
Three-year outcomes after high hyperopia correction using photorefractive keratectomy with a large ablation zone
Authors: Kaluzny Bartlomiej J , Piotrowiak-Slupska Ilona , Kaszuba-Modrzejewska Magdalena , Stachura Joanna , Arba-Mosquera Samuel , Verma Shwetabh
Published: August 2018

Aim

To evaluate refractive and visual outcomes of photorefractive keratectomy (PRK) to treat high hyperopia using an aberration-neutral profile and large ablation zone.

Methods

This was a retrospective, consecutive observational case series at the Oftalmika Eye Hospital, Bydgoszcz, Poland. We included 51 consecutive eyes of 34 patients who underwent alcohol-assisted PRK to correct hyperopia within the range of +3.6 to +6.15 D (mean+4.61±0.67 D). Procedures were performed with an Amaris 750S excimer laser (Schwind eye-tech-solutions GmbH, Kleinostheim, Germany) using an aberration-neutral profile and a 10 mm total ablation zone. Refractive results, predictability, safety and efficacy were evaluated 3 years postoperatively.

Results

At 1-year postsurgery, the mean manifest refraction spherical equivalent (MRSE) was −0.002±0.43 D and mean cylinder was −0.181±0.31 D, while the values were +0.09±0.46 D and −0.15±0.26 D, respectively, at 2 years (MRSE p<0.001) and +0.15±0.44 D and −0.15±0.26 D, respectively, at 3 years (MRSE p<0.001). 78% of eyes were within ±0.50 D of the attempted spherical equivalent correction. Three years postoperatively, 22% of eyes lost one line of corrected distance visual acuity and 27% gained a line or two. The change in the mean corneal spherical aberrations for the 6 mm zone was from 0.27±0.07 to 0.08±0.13 µm.

Conclusions

High hyperopia correction with PRK using an aberration-neutral profile and large ablation zone provides good efficacy, safety, predictability and visual outcomes. Relatively low change of corneal spherical aberrations and low increase of hyperopia in the first three postoperative years were observed.
Prevalence of anaphylaxis among adults admitted to critical care for severe asthma exacerbation
Authors: Akenroye Ayobami T , Ajala Abayomi , Azimi-Nekoo Elham , de Vos Gabriele S
Published: August 2018

Background

In asthmatics, making a diagnosis of anaphylaxis could be challenging as respiratory symptoms are a common feature of both conditions. Identifying anaphylaxis is important to providing appropriate care. A prior study showed that anaphylaxis is sometimes misdiagnosed as acute asthma in children. We sought to identify the percentage of adults admitted to the intensive care unit (ICU) with asthma exacerbations who met criteria for anaphylaxis.

Methods

Retrospective chart review of adults admitted with acute asthma to the ICU at Jacobi Medical Center, a Level 1 trauma centre in Bronx, New York. Study period was January 2012 to December 2014. Using the criteria outlined in the World Allergy Organization’s Anaphylaxis Guidelines, we identified patients who met criteria for anaphylaxis.

Results

105 patients were identified: 17 were excluded because their main reason(s) for admission was not asthma. 7 (8%) of the 88 cases eligible for the study met diagnostic criteria for anaphylaxis while 3 (3.4%) were highly likely to have had anaphylaxis. The baseline characteristics of the seven patients were similar to that of the overall population studied. They however had shorter onset of symptoms (median (IQR): 3.5 (2–6) vs 24 hours (12–72), p<0.001), were more likely to have been intubated (71%vs31%, p=0.04), received intramuscular epinephrine by the emergency medical services or in the emergency room (86%vs42%, p=0.04) and received antihistamines (28.6%vs1.2%, p=0.02). None of these seven patients died. Only one of the seven patients was prescribed an epinephrine pen injector and referred to an allergist at discharge.

Conclusion

In this single-centre retrospective review, 3.4% of adults admitted to the ICU for acute severe asthma also met criteria for anaphylaxis.
A mixed methods study of the impact of consultant overnight working in an English Emergency Department
Authors: Penn Marion L , Monks Thomas , Pope Catherine , Clancy Mike
Published: August 2018

Background

There is a growing expectation that consultant-level doctors should be present within an ED overnight. However, there is a lack of robust evidence substantiating the impact on patient waiting times, safety or the workforce.

Objectives

To evaluate the impact of consultant-level doctors overnight working in ED in a large university hospital.

Methods

We conducted a controlled interrupted time series analysis to study ED waiting times before and after the introduction of consultant night working. Adverse event reports (AER) were used as a surrogate for patient safety. We conducted interviews with medical and nursing staff to explore attitudes to night work.

Results

The reduction seen in average time in department relative to the day, following the introduction of consultant was non-significant (−12 min; 95% CI −28 to 4, p=0.148). Analysis of hourly arrivals and departures indicated that overnight work was inherited from the day. There were three (0.9%) moderate and 0 severe AERs in 1 year. The workforce reported that night working had a negative impact on sleep patterns, performance and well-being and there were mixed views about the benefits of consultant night presence. Additional time off during the day acted as compensation for night work but resulted in reduced contact with ED teams.

Conclusions

Our single-site study was unable to demonstrate a clinically important impact of consultant night working on total time patients spend in the department. Our analysis suggests there may be more potential to reduce total time in department during the day, at our study site. Negative impacts on well-being, and likely resistance to consultant night working should not be ignored. Further studies of night working are recommended to substantiate our results.
Eighty-two-year-old man with a systolic murmur
Authors: Kupsky Daniel F , Ananthasubramaniam Karthikeyan , Lee James
Published: August 2018

Clinical Introduction

An 82-year-old man with a history of coronary artery bypass surgery, hypertension and small bowel gastrointestinal stromal tumour underwent cardiac risk evaluation prior to surgical resection of his tumour. He was asymptomatic from a cardiovascular perspective, but his activity level was less than four metabolic equivalents. Physical examination was notable for a 2/6 systolic murmur at the apex. ECG showed sinus rhythm. A transthoracic echocardiogram was performed (figure 1 and online supplementary video 1).

Supplementary file 1

Figure 1

Transthoracic echocardiography. (A) Mitral valve continuous wave Doppler and (B) tricuspid valve continuous wave Doppler.

QUESTION:

The findings in figure 1 are most likely due to which of the following?

Atrioventricular conduction block.

Acute severe aortic regurgitation.

Patent ductus arteriosus.

Atrial flutter.

Severe mitral stenosis.
Testing messages about comparative risk of electronic cigarettes and combusted cigarettes
Authors: Yang Bo , Owusu Daniel , Popova Lucy
Published: August 2018

Introduction

Health agencies are grappling with communicating risks of electronic cigarettes (e-cigarettes) compared with combusted cigarettes. This study examined smokers’ responses to two types of comparative risk messages with one type incorporating more negative antismoking elements in the design.

Methods

In an online experiment, 1400 US adult (18+ years) current smokers and recent quitters were randomised to view one of three comparative risk messages about e-cigarettes (CR messages), one of three comparative risk messages that included more negative antismoking elements in the design (CR− messages) or a control message. Selection of outcomes was guided by the antismoking message impact framework. Multivariate analyses of covariance and logistic regression models analysed effects of messages on message evaluations, e-cigarette-related and cigarette-related beliefs and behavioural intentions.

Results

Both CR and CR− messages decreased smokers’ intentions to smoke cigarettes, increased intentions to switch to e-cigarettes completely and increased perceptions that e-cigarettes are less harmful than combusted cigarettes. Neither message type increased dual use intentions relative to exclusive e-cigarettes use or smoking cessation. CR messages decreased perceived absolute risks of e-cigarettes and self-exempting beliefs about smoking, whereas CR− versus CR messages produced higher self-efficacy to quit smoking.

Conclusion

Comparative risk communication might encourage smokers to switch to lower-harm tobacco products. Comparative risk messages with more negative antismoking elements in the design might be particularly effective, because they led to higher self-efficacy to quit smoking. Regulatory agencies may consider using comparative risk messages with more negative antismoking elements to educate the public about lower risk of e-cigarettes.
Classification of El Niño and La Niña years for water resources management in Alberta
Authors: Islam Zahidul
Published: August 2018

Classification of El Niño and La Niña years in a historical time period is necessary to analyze their impacts on hydrology and water resources management. In this study, various El Niño-Southern Oscillation (ENSO) indices, and how they are used to classify El Niño or La Niña years have been reviewed. Based on the review, a simple method of classifying El Niño or La Niña years has been proposed.
Design of Broadband LNA Using Improved Self-Bias Architecture
Authors: Qi Tian , He Songbai
Published: August 2018

A broadband low-noise amplifier (LNA) using 0.13 [Formula: see text]m GaAs HEMT technology for Ku-band applications is presented in this paper. By introducing an improved self-bias architecture, the LNA is achieved with low noise figure (NF) and high power gain. Compared with traditional LNA, self-bias architecture can reduce DC supplies to single one, and the improved architecture proposed here also takes part in source matching to reduce the complexity matching networks for broadband applications. To verify, an LNA operating over 12–18-GHz bandwidth is fabricated. The measurement results, for all the 72 chips on the wafer, and their average values are in great accordance with the simulation results, with 25.5–27.5-dB power gain, 1.1–1.8-dB NF, 15–17.5-dBm output power at [Formula: see text] and with a chip size of 2 mm [Formula: see text] 1.5 mm.
A geometric statement of the Harnack inequality for a degenerate Kolmogorov equation with rough coefficients
Authors: Anceschi Francesca , Eleuteri Michela , Polidoro Sergio
Published: August 2018

We consider weak solutions of second-order partial differential equations of Kolmogorov–Fokker–Planck-type with measurable coefficients in the form [Formula: see text] where [Formula: see text] is a symmetric uniformly positive definite matrix with bounded measurable coefficients; [Formula: see text] and the components of the vector [Formula: see text] are bounded and measurable functions. We give a geometric statement of the Harnack inequality recently proved by Golse et al. As a corollary, we obtain a strong maximum principle.
The Chalk Group (Upper Cretaceous) of the Northern Province, eastern England – a review
Authors: Mitchell Simon F.
Published: August 2018

A review of the Chalk of the Northern Province recognizes six formations, five of which (Hunstanton, Ferriby, Welton, Burnham and Flamborough formations) crop out in northern Norfolk, Lincolnshire and Yorkshire, and a sixth (Rowe Formation) is buried beneath the drift of Holderness. The Hunstanton, Ferriby and Flamborough formations are largely devoid of flints, whereas the Welton (other than its two basal members) and Burnham formations have nodular and tabular flints, respectively. Previous work on the lithostratigraphy and marker beds is presented, and an overview of the distribution of the more important macrofossils is provided. Especial attention is given to the succession at Speeton through the Hunstanton, Ferriby and lower Welton formations with details of the oxygen and carbon isotope signatures. The Speeton section is internationally important because of its expanded Albian-Mid Cenomanian succession. Small sections of the Burnham Formation in Speeton–Buckton cliffs are also presented for the first time. The appendix reviews the relevant Cretaceous stage boundaries with reference to the Chalk of the Northern Province together with details of the fossil zones that are used in this paper.
Geophysical log characterization of the Flamborough Chalk Formation (Late Cretaceous, Santonian – Early Campanian), East Yorkshire, UK: implications for understanding the onshore and offshore occurrence of the Late Campanian Rowe Chalk Formation
Authors: Woods M. A.
Published: August 2018

Whilst borehole geophysical log profiles have been matched with formational subdivisions for large parts of the Chalk Group in Lincolnshire and Yorkshire, characterization of the youngest and thickest part of the outcropping succession, represented by the marl-rich and largely flint-free Flamborough Chalk Formation, has been hindered by lack of cored and geophysically logged boreholes. In the absence of optimal primary data, a stratigraphical interpretation of geophysical logs in the Flamborough Chalk has been developed by comparison of logs from deep hydrocarbons boreholes (penetrating more than 260 m of Flamborough Chalk) beneath Holderness (East Yorkshire) with generalized patterns of outcrop stratigraphy. This approach reveals geophysical log patterns that are consistent with lithology and thickness variations seen at outcrop, compatible with core and geophysical data for a deep borehole in the Flamborough Chalk at Carnaby (near Bridlington), and traceable northwards and westwards towards the margin of the Flamborough Chalk outcrop. These interpretations, and comparisons with geophysically logged offshore successions, suggest the presence of Flamborough Chalk beneath Holderness that is younger (?Late Campanian) than anything seen at outcrop, and, with the exception of possible
ex-situ
chalk rafts of glacial origin, cast doubt on the likely subsurface onshore extent of typically flint-rich Rowe Chalk Formation.
Skeletal muscle fiber characteristics in patients with chronic heart failure: impact of disease severity and relation with muscle oxygenation during exercise
Authors: Niemeijer Victor M. , Snijders Tim , Verdijk Lex B. , van Kranenburg Janneau , Groen Bart B. L. , Holwerda Andrew M. , Spee Ruud F. , Wijn Pieter F. F. , van Loon Luc J. C. , Kemps Hareld M. C.
Published: August 2018

Skeletal muscle function in patients with heart failure and reduced ejection fraction (HFrEF) greatly determines exercise capacity. However, reports on skeletal muscle fiber dimensions, fiber capillarization, and their physiological importance are inconsistent. Twenty-five moderately impaired patients with HFrEF and 25 healthy control (HC) subjects underwent muscle biopsy sampling. Type I and type II muscle fiber characteristics were determined by immunohistochemistry. In patients with HFrEF, enzymatic oxidative capacity was assessed, and pulmonary oxygen uptake (V̇o2) and skeletal muscle oxygenation during maximal and moderate-intensity exercise were measured using near-infrared spectroscopy. While muscle fiber cross-sectional area (CSA) was not different between patients with HFrEF and HC, the percentage of type I fibers was higher in HC (46 ± 15 vs. 37 ± 12%, respectively, P = 0.041). Fiber type distribution and CSA were not different between patients in New York Heart Association (NYHA) class II and III. Type I muscle fiber capillarization was higher in HFrEF compared with HC[capillary-to-fiber perimeter exchange (CFPE) index: 5.70 ± 0.92 vs. 5.05 ± 0.82, respectively, P = 0.027]. Patients in NYHA class III had slower V̇o2 and muscle deoxygenation kinetics during onset of exercise and lower muscle oxidative capacity than those in class II ( P < 0.05). Also, fiber capillarization was lower but not compared with HC. Higher CFPE index was related to faster deoxygenation ( rspearman = −0.682, P = 0.001), however, not to muscle oxidative capacity ( r = −0.282, P = 0.216). Type I muscle fiber capillarization is higher in HFrEF compared with HC but not in patients with greater exercise impairment. Greater capillarization may positively affect V̇o2 kinetics by enhancing muscle oxygen diffusion.

NEW & NOTEWORTHY The skeletal myopathy of chronic heart failure (HF) includes a greater percentage of fatigable type II fibers and, for less impaired patients, greater skeletal muscle fiber capillarization. Near-infrared spectroscopy measurements of skeletal muscle oxygenation indicate that greater capillarization may compensate for reduced blood flow in mild HF by enhancing the diffusive capacity of skeletal muscle. This thereby augments and speeds oxygen extraction during contractions, which is translated into faster pulmonary oxygen uptake kinetics.
Acclimatization of low altitude-bred deer mice (Peromyscus maniculatus) to high altitude
Authors: Dane D. Merrill , Cao Khoa , Lu Hua , Yilmaz Cuneyt , Dolan Jamie , Thaler Catherine D. , Ravikumar Priya , Hammond Kimberly A. , Hsia Connie C. W.
Published: August 2018

A colony of deer mice subspecies ( Peromyscus maniculatus sonoriensis) native to high altitude (HA) has been maintained at sea level for 18–20 generations and remains genetically unchanged. To determine if these animals retain responsiveness to hypoxia, one group (9–11 wk old) was acclimated to HA (3,800 m) for 8 wk. Age-matched control animals were acclimated to a lower altitude (LA; 252 m). Maximal O2uptake (V̇o2max) was measured at the respective altitudes. On a separate day, lung volume, diffusing capacity for carbon monoxide (DLCO), and pulmonary blood flow were measured under anesthesia using a rebreathing technique at two inspired O2tensions. The HA-acclimated deer mice maintained a normal V̇o2maxrelative to LA baseline. Compared with LA control mice, antemortem lung volume was larger in HA mice in a manner dependent on alveolar O2tension. Systemic hematocrit, pulmonary blood flow, and standardized DLCOdid not differ significantly between groups. HA mice showed a higher postmortem alveolar-capillary hematocrit, larger alveolar ducts, and smaller distal conducting structures. In HA mice, absolute volumes of alveolar type I epithelia and endothelia were higher whereas that of interstitia was lower than in LA mice. These structural changes occurred without a net increase in whole-lung septal tissue-capillary volumes or surface areas. Thus, deer mice bred and raised to adulthood at LA retain phenotypic plasticity and adapt to HA without a decrement in V̇o2maxvia structural (enlarged airspaces, alveolar septal remodeling) and nonstructural (lung expansion under hypoxia) mechanisms and without an increase in systemic hematocrit or compensatory lung growth.

NEW & NOTEWORTHY Deer mice ( Peromyscus maniculatus) are robust and very active mammals that are found across the North American continent. They are also highly adaptable to extreme environments. When introduced to high altitude they retain remarkable adaptive ability to the low-oxygen environment via lung expansion and remodeling of existing lung structure, thereby maintaining normal aerobic capacity without generating more red blood cells or additional lung tissue.
A Standardized Approach to Quantitative Analysis of Nicotine in e-Liquids Based on Peak Purity Criteria Using High-Performance Liquid Chromatography
Authors: Gholap Vinit V. , Kosmider Leon , Halquist Matthew S.
Published: August 2018

The use of electronic cigarettes (e-cigarettes) is a growing trend in population. E-cigarettes are evolving at a rapid rate with variety of battery powered devices and combustible nicotine refills such as e-liquids. In contrast to conventional cigarettes which are studied well for their toxicity and health effects, long-term clinical data on e-cigarettes are not available yet. Therefore, safety of e-cigarettes is still a major concern. Although the Food and Drug Administration (FDA) has recently started regulating e-cigarette products, no limits on nicotine and other ingredients in such products have been proposed. Considering the regulatory requirements, it is critical that reliable and standardized analytical methods for analyzing nicotine and other ingredients in e-cigarette products such as e-liquids are available. Here, we are reporting a fully validated high-performance liquid chromatography (HPLC) method based on nicotine peak purity for accurately quantifying nicotine in various e-liquids. The method has been validated as per ICH Q2(R1) and USP <1225> guidelines. The method is specific, precise, accurate, and linear to analyze nicotine in e-liquids with 1 to >50 mg/mL of nicotine. Additionally, the method has been proven robust and flexible for parameters such as change in flow rate, column oven temperature, and organic phase composition, which proves applicability of the method over wide variety of e-liquids in market.
Comparison of Complication and Success Rates of ProGlide Closure Device in Patients Undergoing TAVI and Endovascular Aneurysm Repair
Authors: Durmuş Gündüz , Belen Erdal , Bayyiğit Akif , Can Mehmet Mustafa
Published: August 2018

Introduction. Usage of the Perclose ProGlide® (PP: Abbott Laboratories, Chicago, IL, USA) closure device is becoming increasingly prevalent during percutaneous endovascular aortic repair (EVAR) and transcatheter aortic valve implantation (TAVI). The respective conditions treated via these procedures, abdominal aortic aneurysm and aortic valve stenosis, share risk factors but are two different physiopathological problems. Aim. Our aim was to compare the complication and success rates of PP closure device use in patients undergoing EVAR and TAVI. Materials and Methods. A total of 74 patients, including 58 undergoing TAVI and 16 undergoing EVAR, were analysed in our study. Results. Of the TAVI patients treated using the PP closure device, two (3.4%) had access to site-related bleeding complications and two (3.4%) experienced device failure. Of the EVAR patients who received the PP closure device, three (18.8%) had bleeding complications and three (18.8%) experienced device failure. Conclusion. Due to the underlying diffuse aortic wall pathology, the success rate of PP closure device use was lower and the complication rate of PP closure device was higher in the EVAR group versus the TAVI group.
Outer Synchronization of a Modified Quorum-Sensing Network via Adaptive Control
Authors: Zhang Jianbao , Zhang Wenyin , Zhang Denghua , Yang Chengdong , Zhu Kongwei , Qiu Jianlong
Published: August 2018

Motivated by the quorum-sensing mechanism of bacteria, this paper modifies the network model by adding unknown parameters and noise disturbances and investigates the problem of outer synchronization via adaptive control. In case there exist three unknown parameters, updating laws are presented to identify the unknown parameters with help of Lyapunov stability theory, and the negative effects of noise disturbances are also compensated by designing adaptive controllers. In addition, we simplify the obtained conditions and carry out two succinct and utilitarian corollaries. Finally, numerical simulations are provided to show the validity of the obtained results.
Evaluation of Human Exposure toAedesBites in Rubber and Palm Cultivations Using an Immunoepidemiological Biomarker
Authors: Yobo Céline Mabot , Sadia-Kacou Cécile Agnimou Malanfoua , Adja Maurice Akré , Elanga-Ndille Emmanuel , Sagna André Barembaye , Guindo-Coulibaly Négnorogo , Poinsignon Anne , Remoue Franck , Koudou Benjamin Guibéhi
Published: August 2018

Arbovirus infections, mainly transmitted byAedesmosquito, are emerging in Africa. Efficient vector control requires an understanding of ecological factors which could impact on the risk of transmission, such as environmental changes linked to agricultural practices. The present study aims to assess the level of human exposure toAedesmosquito bites in different agroecosystem area, using an immunological tool which quantifies human IgG antibody response to oneAe. aegyptisalivary peptide. Specific IgG responses were assessed during dry and rainy seasons, in children living in different villages in Côte d’Ivoire: N’Zikro (rubber and oil palm exploitations), Ehania-V5 (oil palm), and Ayébo (without intensive agricultural activities). In the dry season, specific IgG levels were significantly lower in Ayébo compared to Ehania-V5 and N’Zikro and, interestingly, were similarly high in both villages with cultivations. In the rainy season, no difference of specific IgG was observed between villages. Specific IgG responses remained therefore high during both seasons in villages associated with intensive agricultural. The rubber and oil palm cultivations could maintain a high level of human exposure toAedesmosquito bites during both dry and rainy seasons. These agricultural activities could represent a permanent risk factor of the transmission of arboviruses.
A Unified Level Set Framework Combining Hybrid Algorithms for Liver and Liver Tumor Segmentation in CT Images
Authors: Zheng Zhou , Zhang Xuechang , Xu Huafei , Liang Wang , Zheng Siming , Shi Yueding
Published: August 2018

Accurate and reliable segmentation of liver tissue and liver tumor is essential for the follow-up of hepatic diagnosis. In this paper, we present a method for liver segmentation and a method for liver tumor segmentation. The two methods are grounded on a novel unified level set method (LSM), which incorporates both region information and edge information to evolve the contour. This level set framework is more resistant to edge leakage than the single-information driven LSMs for liver segmentation and surpasses many other models for liver tumor segmentation. Specifically, for liver segmentation, a hybrid image preprocessing scheme is used first to convert an input CT image into a binary image. Then with manual setting of a few seed points on the obtained binary image, the following region-growing is performed to extract a rough liver region with no leakage. The unified LSM is proposed at last to refine the segmentation result. For liver tumor segmentation, a local intensity clustering based LSM coupled with hidden Markov random field and expectation-maximization (HMRF-EM) algorithm is applied to construct an enhanced edge indicator for the unified LSM. With this development, expected segmentation results can be obtained via the unified LSM, even for complex tumors. The two methods were evaluated with various datasets containing a local hospital dataset, the public datasets SLIVER07, 3Dircadb, and MIDAS via five measures. The proposed liver segmentation method outperformed other previous semiautomatic methods on the SLIVER07 dataset and required less interaction. The proposed liver tumor segmentation method was also competitive with other state-of-the-art methods in both accuracy and efficiency on the 3Dircadb database. Our methods are evaluated to be accurate and efficient, which allows their adoptions in clinical practice.
H∞ Optimal Performance Design of an Unstable Plant under Bode Integral Constraint
Authors: Meng Fanwei , Pang Aiping , Dong Xuefei , Han Chang , Sha Xiaopeng
Published: August 2018

This paper proposed the H∞ state feedback and H∞ output feedback design methods for unstable plants, which improved the original H∞ state feedback and H∞ output feedback. For the H∞ state feedback design of unstable plants, it presents the complete robustness constraint which is based on solving Riccati equation and Bode integral. For the H∞ output feedback design of unstable plants, the medium‐frequency band should be considered in particular. Besides, this paper presents the method to select weight function or coefficients in the H∞ design, which employs Bode integral to optimize the H∞ design. It takes a magnetic levitation system as an example. The simulation results demonstrate that the optimal performance of perturbation suppression is obtained with the design of robustness constraint. The presented method is of benefit to the general H∞ design.