bluuebunny/crossref_metadata_2025 huggingface dataset:
Coupling techniques for computational non-linear transient aeroelasticity
Authors: Unger R , Haupt M C , Horst P
Published: July 2008

Some numerical aspects for the coupling process of a discrete non-linear aeroelastic system are presented. The objective of this paper is two-fold: first, a consistent time-integration method of the whole coupled system is developed and the robustness is shown. Second, several data transfer methods — conservative interpolation, Galerkin-based transfer, dual-Lagrange-based transfer, and Sobolev-norm-based transfer — are employed and the importance of an accurate transfer scheme is demonstrated. Numerical results obtained from simulations of an oscillating one-dimensional plate in a transonic flow and a three-dimensional wing example serve as a typical benchmark problem to show the applicability of the presented concepts and the importance on the behaviour of an aeroelastic system.
Closed versus open cycle energy recovery from solid oxide fuel cells
Authors: Angelino G , Invernizzi C , Iora P
Published: July 2008

A computer model of a solid oxide fuel cell (SOFC) was implemented with a number of operational options to evaluate the best use of the cell waste heat. The simplest solution for heat recovery is represented by adopting a pressurized fuel cell with the eventual expansion of the exhaust stream in a gas turbine. Other alternatives feature the adoption of various closed cycle recovery systems: a standard steam cycle, an inter-refrigerated helium cycle, and an advanced binary cycle. Assuming a fuel energy input of 100 MW, the overall efficiency of a hybrid cell was computed, which was much higher than that of a small capacity (100 kW) existing plant (67 versus ∼53 per cent). Such high efficiency hybrid SOFC systems were taken as the reference to evaluate the performance of alternate options. Reclaiming the cell waste heat by means of a subcritical steam cycle yields a performance similar to that of a hybrid system. Similar results are obtained resorting to a closed helium cycle. Advanced binary cycles, using either potassium or cesium as working fluids, were extensively investigated in view of achieving a superior overall performance. The hot, clean stream exhausted by the fuel cell is recognized as an ideal heat source for a binary plant. The SOFC-binary cycle system was fully optimized yielding top efficiencies ∼74 per cent and an additional power output of ∼45 per cent of the cell rating (30 per cent in the case of the hybrid system). The excellent efficiency of a binary cycle combined with the large amount of oxygen that is available in the cell exhaust flow suggests that a supplementary firing of the fuel could improve the overall merit of the system. Burning 75 per cent of the additional natural gas, for example, reduces the total efficiency to a level of that of a hybrid system but makes available an extra power 1.35 times greater than the fuel cell capacity. Pushing further this concept, the fuel cell could become an auxiliary equipment of a binary cycle.
Cavitation in a non-circular opening spool valve with U-grooves
Authors: Zou J , Fu X , Du X W , Ruan X D , Ji H , Ryu S , Ochiai M
Published: July 2008

A numerical method and an experimental analysis were applied to obtain a better understanding on the characteristics of cavitation inside the non-circular opening spool valve with U-grooves. The relationship between structural parameters and cavitating flow inside the valve, as well as acoustic noise, are studied. A two-staged flow resistance model was brought forward for the qualitative prediction of the cavitation intensity and incipient cavitation number inside the valve. The throttling effect of the first throttling stage plays an important role in the incipience and development of cavitation inside the valve. The reduction of pressure loss caused by the first throttling stage benefits to the cavitation resistance. With the decrease of cavitation number, the acoustic noise level increases until the former reaches the critical value (σ=0.04). Once cavitation number is below the critical value, the flowrate of the valve is choked, and the acoustic noise level decreases instead.
Cooling, heating, and power energy performance for system feasibility
Authors: Fumo N , Mago P J , Chamra L M
Published: July 2008

Buildings with heating and cooling energy requirements are usually supplied by separated systems such as furnaces or boilers for heating, and vapour compression systems for cooling. For these types of buildings, the use of cooling, heating, and power (CHP) systems is an alternative for energy savings. Different investigations have claimed that the use of CHP systems reduces the energy consumption related to transmission and distribution of energy. However, most of these analyses are based on the reduction of operating cost without measuring the actual energy use reduction. In this study, the definition of building primary energy ratio (BPER) is introduced as a new parameter to evaluate the CHP energy performance. BPER measures the variation of the building primary energy (BPE) when the building is operated without a CHP system versus the BPE when a CHP system is used. Results show that using the thermal efficiency alone is not the best approach to describe the CHP system energy performance and that using the BPER provides a more comprehensive CHP evaluation. For this investigation, values of BPER greater than 1 indicate that primary energy is being saved for that specific time, which makes this concept a reliable tool for the CHP design and operational control.
Film thickness variations in elasto-hydrodynamically lubricated circular contacts induced by oscillatory entrainment speed conditions
Authors: Venner C H , Hagmeijer R
Published: July 2008

In this paper, the effects of an oscillatory entrainment speed on the film thickness in an elasto-hydrodynamically lubricated circular contact operating in the piezo-viscous regime as predicted by a conventional elasto-hydrodynamic lubrication model are described in detail. The relative variation of the film thickness on the centreline of the contact mainly depends on two dimensionless parameters: relative entrainment velocity amplitude and dimensionless entrainment velocity frequency. For small to moderate values of dimensionless frequency, the results can be accurately predicted through a simplified ‘engineering approach’: propagation of inlet modulations along oscillatory characteristics. For values of the dimensionless frequency of O(1), film thickness modulations occur on a sub-contact scale. This work was initiated by the experimental results of Glovnea and Spikes obtained for two lubricants PAO and 5P4E, which have the same ambient viscosity but a different viscosity—pressure coefficient. During the experiments significant difference in behaviour was observed. In this paper, it is shown that a conventional model assuming Newtonian rheological behaviour predicts the same relative film thickness results for both the lubricants. This agrees well with the behaviour observed for PAO, which can be considered as a standard oil that is well characterized by its bulk viscosity, density, and their pressure dependence alone. Nevertheless, further experiments need to be carried out to validate the predictions for larger values of the dimensionless frequency. The behaviour observed in the experiments for 5P4E is significantly different. For accurate prediction of friction, the need to include non-Newtonian lubricant behaviour in models is well known. Film thickness predictions are often less sensitive to the specifics of the lubricant behaviour. However, the results presented here indicate that for film thickness calculations, under rapidly varying conditions in time, more advanced rheological models, including visco-elastic behaviour, may have to be considered as well.
A note on the lubricating film in hydrostatic mechanical face seals
Authors: Luan Z , Khonsari M M
Published: July 2008

A hydrostatic model for analysing the lubrication film in mechanical seals with provision for surface roughness is presented. The model takes into account the wedge angle between the seal faces developed due to thermal gradient. It is useful for predicting the mean pressure distribution, fluid-film thickness, power loss, and leakage rate. An analytical solution for the fluid pressure distribution is obtained by solving the axis-symmetric Reynolds equation, without assuming constant fluid-film thickness. It is demonstrated that surface roughness considerably increases the mean fluid-film thickness. On the basis of predicted film thickness, the leakage rate and dissipated power can be easily predicted. The method and results can be useful as an adjunct analysis for more complicated thermoelastohydrodynamic analysis of mechanical seals.
Non-linear transient analysis of multiple axial groove water-lubricated journal bearings
Authors: Pai R S , Pai R
Published: July 2008

The stability characteristics of water-lubricated journal bearings having multiple axial grooves are studied theoretically. These bearings can use the process fluid as the lubricant as in the case of feed water pumps. The process fluid (water) is fed from one end of the bearing, through the multiple axial grooves (groove angles may vary). A non-linear analysis of a rigid rotor supported on journal bearings under unidirectional constant load, unidirectional periodic load, and variable rotating load is carried out.

The time-dependent Reynolds equation in two-dimension for incompressible fluid is solved numerically by the finite-difference method with a successive over relaxation scheme satisfying the Jakobsson—Floberg—Olsson boundary conditions, to obtain the hydrodynamic forces. Using these forces, the equations of motion are solved by the fourth-order Runge—Kutta method to predict the transient behaviour of the rotor. The analysis gives the orbital trajectory within the clearance circle.
Effect of hydrodynamic pressures near solid surfaces in the incubation stage of cavitation erosion
Authors: Chen H S , Wang J D , Li Y J , Chen D R
Published: July 2008

Ultrasonic vibration cavitation erosion experiments were performed to study the erosion on a steel specimen at different pitch angles. Experimental results show that the number and size of the erosion pits decrease as the pitch angle increases. This result is thought to be related to the hydrodynamic pressures generated near the solid surface. Numerical analyses from the Reynolds equation prove that the hydrodynamic pressures are generated in the fluid film when a bubble is moving towards the surface of the specimen. Simulation of the bubble collapse process shows that the hydrodynamic pressures shorten the collapse time of a bubble and strengthen the microjet at the moment of bubble collapse. As the pitch angle of the specimen surface increases, the squeeze pressure due to normal velocity decreases, and the increased dynamic pressure due to tangential velocity cannot compensate for the loss of the squeeze pressure. Thus, the total hydrodynamic pressure decreases, and a decrement in the number and the size of the erosion pits occurs.
Behaviour of hydromagnetic squeeze films between two conducting rough porous circular plates
Authors: Vadher P A , Vinodkumar P C , Deheri G M , Patel R M
Published: July 2008

In this paper, the problem of squeeze films between electrically conducting rough porous surfaces and electrically conducting lubricant in the presence of transverse magnetic field is investigated for circular shape of the bearing surfaces. The bearing surfaces are assumed to be transversely rough. The roughness of the bearing surface is modelled by a stochastic random variable with non-zero mean, variance, and skewness. The associated Reynolds equation is stochastically averaged with respect to the random roughness parameter. Then, it is solved with appropriate boundary conditions to get the pressure distribution, which is further used to obtain the load carrying capacity leading to the calculation of response time. The results are presented graphically. It is noticed that the bearing suffers on account of transverse surface roughness in general. However, the situation can be retrieved up to a certain extent in the case of negatively skewed roughness especially, when negative variance occurs by suitable choice of plate conductivities. In addition, it is observed that the bearing with magnetic field can support a load even when there is no flow.
Air-bearing surface design of an optical flying head considering dynamic characteristics
Authors: Lee J , Kim J , Park N-C
Published: July 2008

The near-field recording (NFR) system requires the clearance between a slider and disk surface in order to maintain the significant effect on the evanescent wave. The optical flying head (OFH) should also have a small pitch to control the contamination effect. The larger the gap between the leading edge of the slider and the disk, the more the particles come into solid immersion lens (SIL), thereby causing a negative influence on the NFR system. However, the flying stability turns out to be ineffective as the pitch angle reduces. Accordingly, it is necessary to consider dynamic characteristics of OFH in air-bearing surface (ABS) design. The objective of the ABS design is such that the flying height (FH) of the OFH should be as flat as possible over the inner diameter (ID) and outer diameter (OD) of the disk, and FH should be controlled at about 50 nm for both ID and OD in the static state. The better NFR system can also be obtained by a smaller modulation. The numerical optimization in the static state is first carried out, and the dynamic optimization is subsequently performed based on the static optimal model. The dynamic simulation and experiments are additionally performed to verify the proposed design optimization results.
Characterization of the friction properties of various coatings at the tool—chip—workpiece interfaces in dry machining of AISI 4140 steel
Authors: Rech J , Claudin C , Grzesik W , Zalisz Z
Published: July 2008

This work deals with the development of a new tribometer designed for the characterization of the frictional properties at the tool—chip—workpiece interfaces in cutting processes. The average contact pressure can be selected up to 3 GPa under sliding velocities reaching 300 m/min. Moreover, the system provides a continuously regenerated contact surface. Under such severe conditions, which are not reachable with conventional tribometers, the apparent friction coefficient is quantified in parallel to the heat flux transmitted to the pin. This new system has been applied to the characterization of the frictional properties during the dry machining of a AISI 4140 treated steel with various coated carbide substrates. The coatings investigated in this work are: TiN, TiAlN, AlCrN coatings deposited by physical vapour deposition (PVD). A wide range of sliding velocities and pressures have been investigated in dry conditions. It has been shown that the coating is the most influential parameter, followed by the sliding velocity, and finally the pressure. As far as the friction coefficient is concerned, the superiority of AlCrN and TiAlN coatings in dry cutting has been revealed.
Optimal passive vibration control of Timoshenko beams with arbitrary boundary conditions traversed by moving loads
Authors: Younesian D , Kargarnovin M H , Esmailzadeh E
Published: July 2008

Passive control of vibration of beams subjected to moving loads is studied in which, an optimal tuned mass damper (TMD) system is utilized to suppress the undesirable beam vibration. Timoshenko beam theory is applied to the beam model having three types of boundary conditions, namely, hinged-hinged, hinged-clamped, and the clamped-clamped ends, and the governing equations of motion are solved using the Galerkin method. For every set of boundary conditions, a minimax problem is solved using the sequential quadratic programming method and the optimum values of the frequency and damping ratios for the TMD system are obtained. To show the effectiveness of the designed TMD system, simulations of an actual railway bridge traversed by the S.K.S. Japanese high-speed train are carried out and the dynamic performance of the bridge before and after the installation of the TMD system are compared.
Modelling and ride dynamics of a flexible multi-body model of an urban bus
Authors: Georgiou G , Badarlis A , Natsiavas S
Published: July 2008

Dynamic response of a large order mechanical model of an urban bus is investigated in this paper. The emphasis is first put on developing a quite complete model, which can be utilized in order to extract sufficiently reliable and accurate information related to its dynamics in a fast way. Since some of the components of the bus undergo large rigid body rotation, in addition to motion resulting from their deformability, a multi-body dynamics framework is adopted. This implies that the resulting equations of motion appear in the form of a strongly non-linear set of differential-algebraic equations, which are difficult to handle even numerically. In fact, the modelling becomes more involved because all the significant non-linearities appearing in the interconnections of the structural components and especially in the front and rear suspension subsystems of the bus are taken into account. In order to alleviate some of these complexities, the number of degrees of freedom of each component, associated with its deformability, is reduced drastically by applying an appropriate coordinate condensation methodology. Finally, this model is employed and numerical results are obtained for motions resulting from typical road excitation. In particular, selected response quantities related to ride comfort are examined for characteristic combinations of the bus suspension stiffness and damping parameters.
Fundamentals of Statistical Evidence—A Primer for Legal Professionals
Authors: Aitken C. G. G. , Taroni F.
Published: July 2008

Criminal courts are today frequently confronted with statistical evidence, notably in relation to DNA profiling. Recent experience tends to confirm both widespread perceptions and more systematic research indicating that probability and statistics are not handled confidently, or always competently, by lawyers, judges, jurors or even by forensic scientists. Conceived as a primer for legal professionals, this article reviews basic statistical terminology and its forensic applications, and explores the options for presenting statistical information to fact-finders effectively. In raising awareness of the issues and by encouraging improved comprehension of probability and statistics amongst legal and forensic science professionals, we aim to contribute directly to the administration of justice by promoting more successful applications of forensic statistics in legal adjudication.
Highly Sensitive Cardiac Troponin T Values Remain Constant after Brief Exercise- or Pharmacologic-Induced Reversible Myocardial Ischemia
Authors: Kurz Kerstin , Giannitsis Evangelos , Zehelein Joerg , Katus Hugo A
Published: July 2008

Background: Using a new precommercial high-sensitivity cardiac troponin T (hsTnT) assay, we evaluated whether hsTnT increases after reversible myocardial ischemia.

Methods: In 195 patients undergoing nuclear stress testing (ST) using single-photon emission computed tomography (SPECT) for suspected ischemic heart disease, we measured hsTnT before and 18 min, 4 h, and 24 h after the stress test. Thirty patients were excluded before ST because of cardiac troponin T (cTnT) >30 ng/L (0.03 μg/L) as measured by the fourth-generation commercial test. Another 65 patients were excluded because of a combination of fixed and reversible perfusion defects (PDs) after SPECT.

Results: We studied 18 patients with reversible PDs, 41 patients with fixed PDs, and 41 patients without any PDs. Of these 100 patients, 61 received dynamic ST and 39 pharmacological ST. Median baseline hsTnT concentrations (25th, 75th percentile) were comparable in patients with reversible, fixed, and no PDs [5.57 (2.47, 12.60), 8.01 (4.55, 12.44), and 6.90 (4.63, 10.59) ng/L, respectively]. After ST, median hsTnT concentrations did not change in the reversible, fixed, or no PD groups from baseline to 18 min [−0.41 (−0.81, 0.01), 0.01 (−0.75, 0.79), and 0.36 (−0.42, 1.01) ng/L] or from baseline to 4 h [−0.56 (−1.82, 0.74), 0.24 (−0.60, 1.45), and 0.23 (−0.99, 1.15) ng/L]. Median baseline hsTnT concentrations tended to be higher in patients undergoing pharmacological vs dynamic ST; however, there were no significant increases in hsTnT concentrations after either type of ST.

Conclusions: Elevation of cTnT is rather a consequence of irreversible myocyte death than reversible myocardial ischemia after exercise or pharmacologic myocardial ischemia.
Elastic deformation mechanisms of softwoods in radial tension – Cell wall bending or stretching?
Authors: Modén Carl S. , Berglund Lars A.
Published: July 2008

Radial softwood modulus E

R
is typically twice as high as the tangential modulus E

T
. The reason for this is unclear, although cell geometry is likely to contribute. The established hexagonal honeycomb model for prediction of E

R
is based on a cell wall bending mechanism only. If cell wall stretching also takes place, the dependence of E

R
on relative density will be different. If experimental data for E

R
as a function of relative density show deviations from cell wall bending predictions, this may indicate the presence of cell wall stretching. A SilviScan apparatus is used to measure density distribution. A procedure by means of digital speckle photography is then developed for measurements of local E

R
within the annual rings of spruce. Comparison is made between experimental data and the two expected density dependencies from cell wall bending and from stretching. The hypothesis of cell wall stretching as a contributing mechanism is supported based on the observed linear dependence of E

R
over a wide density range.
Effects of refining steam pressure on the properties of loblolly pine (Pinus taeda L.) fibers
Authors: Neimsuwan Trairat , Wang Siqun , Philip Ye Xiaofei
Published: July 2008

Medium density fiberboard is widely used with increasing tendency in North America, particularly in the furniture sector, including door skin and cabinets. Sorption property is one of the most important factors for quality judgment. This study will present water vapor sorption behavior of fibers in the range of varying relative humidity from 11% to 89% as affected by steam pressure of thermomechanical refining in small-scale measurement. A 54-year-old loblolly pine tree was refined at 2 to 18 bar of steam pressure. Fiber properties were determined by scanning electron microscope, dynamic contact angle analyzer, wide angle X-ray diffractometer, and water activity meter. The results showed that steam pressure has a dramatic effect on sorption behavior and surface properties of the refined fiber. In conclusion, a higher rate of sorption was found in juvenile fiber at low steam pressure. Higher water activity and lower crystallinity was found at low steam pressure. The sorption isotherm of refined fiber was fitted very well by the Hailwood-Horrobin model.
Exploring Scots pine fibre development mechanisms during TMP processing: Impact of cell wall ultrastructure (morphological and topochemical) on negative behaviour
Authors: Fernando Dinesh , Daniel Geoffrey
Published: July 2008

A study was carried out aiming at understanding the fundamental reasons for different fibre behaviour exhibited by Norway spruce and Scots pine causing large energy consumption differences during thermomechanical pulping (TMP). Ultrastructural characterization of TMP fibres and shives, which were sampled from the two wood species after primary refining, was performed using scanning electron microscopy, transmission electron microscopy (TEM) and TEM-immunogold labelling for their morphological and topochemical properties. As expected, pine wood chips needed higher electrical energy consumption to be refined to a given Canadian Standard Freeness and it produced inferior strength properties compared to spruce. Electron microscopy (EM) observations indicated that the mechanisms of fibre development during primary refining of pine and spruce were different. The two stages of pine fibre separation and development were not concurrent. Results indicated that pine fibre defibration/fracture occurred predominantly through the compound middle lamella/S1 interphase or through the S1 layer producing lesser amounts of shives during the primary refining stage than spruce. In contrast, spruce fibres defibrated mainly through the S2 layer. Detailed EM observations on shives and pulp fibres from TMP revealed the ultrastructural characteristics associated with pine fibre cell walls. Morphological and topochemical features of the S1 layer, S1/S2 interphase, such as lignin and galactoglucomannan distribution across cell walls were explored. The ultrastructural properties are discussed in relation to the TMP parameters (i.e., electrical energy consumption) and strength data. It is concluded that ultrastructural characteristics of Scots pine fibre cell walls govern the different fibre development mechanisms and explain the negative response of this wood during TMP processing.
“Arithmetic of Bedlam!”: Markets and Manhood in Charles Reade's Hard Cash
Authors: Walsh Susan
Published: July 2008

In Charles Reade's underread sensation novel Hard Cash (1863), the hero is imprisoned in an insane asylum so that his father's fiscal crimes may remain concealed. The exposé of asylum abuse that follows this development, together with Reade's fierce critique of how committal laws may be exploited by unscrupulous others, has understandably foregrounded the lunacy plot as the novel's defining feature. This essay, however, presents an economic reading that examines how the lunacy thread extends from the title Hard Cash, which announces the novel's theme. The Cash in question is a coveted and surprisingly mobile sum of money, £14,000, whose nominal amount and vicissitudes reflect aspects of the larger Victorian economy. It is the “one point” toward which action and interests converge. Hard Cash captures a structure of feeling at mid-century, a sense of what it feels like to be an economic man, rendering modern consciousness in melodramatic and sensational modes. By literalizing idioms of anxiety and assaulting male characters with relentless reversals of fortune, Reade dramatizes how economic pressures shape the hero's psychology, behavior, and conception of heroic manliness, fashioning him into a modern subject suited to the commercial age. The examples of madness in Hard Cash extend far beyond the hero's case, and are rooted in financial realities that include unreliable monetary instruments, panic-stricken markets, speculative fevers, and perennial debates about risk, credit, and the nature of money.
Long-Term Safety and Impact on Infection Rates of Postnatal Probiotic and Prebiotic (Synbiotic) Treatment: Randomized, Double-Blind, Placebo-Controlled Trial
Authors: Kukkonen Kaarina , Savilahti Erkki , Haahtela Tari , Juntunen-Backman Kaisu , Korpela Riitta , Poussa Tuija , Tuure Tuula , Kuitunen Mikael
Published: July 2008

OBJECTIVE. Live probiotic bacteria and dietary prebiotic oligosaccharides (together termed synbiotics) increasingly are being used in infancy, but evidence of long-term safety is lacking. In a randomized, placebo-controlled, double-blind trial, we studied the safety and long-term effects of feeding synbiotics to newborn infants.

METHODS. Between November 2000 and March 2003, pregnant mothers carrying infants at high risk for allergy were randomly assigned to receive a mixture of 4 probiotic species (Lactobacillus rhamnosus GG and LC705, Bifidobacterium breve Bb99, and Propionibacterium freudenreichii ssp shermanii) or a placebo for 4 weeks before delivery. Their infants received the same probiotics with 0.8 g of galactooligosaccharides, or a placebo, daily for 6 months after birth. Safety data were obtained from clinical examinations and interviews at follow-up visits at ages 3, 6, and 24 months and from questionnaires at ages 3, 6, 12, and 24 months. Growth data were collected at each time point.

RESULTS. Of the 1018 eligible infants, 925 completed the 2-year follow-up assessment. Infants in both groups grew normally. We observed no difference in neonatal morbidity, feeding-related behaviors (such as infantile colic), or serious adverse events between the study groups. During the 6-month intervention, antibiotics were prescribed less often in the synbiotic group than in the placebo group (23% vs 28%). Throughout the follow-up period, respiratory infections occurred less frequently in the synbiotic group (geometric mean: 3.7 vs 4.2 infections).

CONCLUSION. Feeding synbiotics to newborn infants was safe and seemed to increase resistance to respiratory infections during the first 2 years of life.
Tuberculosis Screening in Internationally Adopted Children: The Need for Initial and Repeat Testing
Authors: Trehan Indi , Meinzen-Derr Jareen K. , Jamison Linda , Staat Mary Allen
Published: July 2008

OBJECTIVE. Because most internationally adopted children come from areas of high tuberculosis prevalence, an initial tuberculin skin test is recommended after arrival to the United States. We evaluated whether repeat testing of children ≥3 months after arrival to the United States would identify additional children with latent tuberculosis infection.

METHODS. Internationally adopted children who were seen at our International Adoption Center and had a tuberculin skin test within 2 months of arrival to the United States were eligible for the study. Children not diagnosed with tuberculosis with initial testing were retested at least 3 months later. The prevalence of tuberculosis on arrival and after repeat testing was determined, and potential risk factors for infection were examined.

RESULTS. Of the 527 internationally adopted children with an initial tuberculin skin test completed, 111 (21%) had evidence of latent tuberculosis infection. Repeat tuberculosis testing was complete for 191 internationally adopted children (46.9% of those who had an initially negative tuberculin skin test). Latent tuberculosis infection was found in 20% of those who were retested. No children were found to have active tuberculosis disease. Children with an initially positive tuberculin skin test result had slightly higher weight-for-age z scores at their initial clinic visit, whereas those whose tuberculin skin test result was positive after repeat testing had slightly lower weight-for-age z scores. A strong correlation between BCG immunization and tuberculin skin test result was observed.

CONCLUSIONS. Latent tuberculosis infection is common in internationally adopted children. A high proportion of internationally adopted children had an initially false-negative tuberculin skin test. Repeat tuberculosis testing of all internationally adopted children with an initially negative tuberculin skin test should be the standard of care for identifying tuberculosis infection and preventing tuberculosis disease in this high-risk population.
What's in a Smile? Maternal Brain Responses to Infant Facial Cues
Authors: Strathearn Lane , Li Jian , Fonagy Peter , Montague P. Read
Published: July 2008

OBJECTIVES. Our goal was to determine how a mother's brain responds to her own infant's facial expressions, comparing happy, neutral, and sad face affect.

METHODS. In an event-related functional MRI study, 28 first-time mothers were shown novel face images of their own 5- to 10-month-old infant and a matched unknown infant. Sixty unique stimuli from 6 categories (own-happy, own-neutral, own-sad, unknown-happy, unknown-neutral, and unknown-sad) were presented randomly for 2 seconds each, with a variable 2- to 6-second interstimulus interval.

RESULTS. Key dopamine-associated reward-processing regions of the brain were activated when mothers viewed their own infant's face compared with an unknown infant's face. These included the ventral tegmental area/substantia nigra regions, the striatum, and frontal lobe regions involved in (1) emotion processing (medial prefrontal, anterior cingulate, and insula cortex), (2) cognition (dorsolateral prefrontal cortex), and (3) motor/behavioral outputs (primary motor area). Happy, but not neutral or sad own-infant faces, activated nigrostriatal brain regions interconnected by dopaminergic neurons, including the substantia nigra and dorsal putamen. A region-of-interest analysis revealed that activation in these regions was related to positive infant affect (happy > neutral > sad) for each own–unknown infant-face contrast.

CONCLUSIONS. When first-time mothers see their own infant's face, an extensive brain network seems to be activated, wherein affective and cognitive information may be integrated and directed toward motor/behavioral outputs. Dopaminergic reward-related brain regions are activated specifically in response to happy, but not sad, infant faces. Understanding how a mother responds uniquely to her own infant, when smiling or crying, may be the first step in understanding the neural basis of mother–infant attachment.
Overweight in Children and Adolescents in Relation to Attention-Deficit/Hyperactivity Disorder: Results From a National Sample
Authors: Waring Molly E. , Lapane Kate L.
Published: July 2008

OBJECTIVE. As the prevalence of childhood obesity increases, identifying groups of children who are at increased risk of overweight is important. The current study estimated the prevalence of overweight in children and adolescents in relation to attention-deficit/hyperactivity disorder and medication use.

PATIENTS AND METHODS. This study was a cross-sectional analysis of 62 887 children and adolescents aged 5 to 17 years from the 2003–2004 National Survey of Children's Health, a nationally representative sample of children and adolescents in the United States. Attention-deficit disorder/attention-deficit/hyperactivity disorder was determined by response to the question “Has a doctor or health professional ever told you that your child has attention-deficit disorder or attention-deficit/hyperactive disorder, that is, ADD or ADHD?” Children and adolescents were classified as underweight, normal weight, at risk of overweight, or overweight according to BMI for age and gender.

RESULTS. After adjustment for age, gender, race/ethnicity, socioeconomic status, and depression/anxiety, children and adolescents with attention-deficit disorder/attention-deficit/hyperactivity disorder not currently using medication had ∼1.5 times the odds of being overweight, and children and adolescents currently medicated for attention-deficit disorder/attention-deficit/hyperactivity disorder had ∼1.6 times the odds of being underweight compared with children and adolescents without either diagnosis.

CONCLUSIONS. This study provides heightened awareness for pediatric providers about the relationship between attention-deficit disorder/attention-deficit/hyperactivity disorder, medication use, and weight status. Future work is needed to better understand the longitudinal and pharmacologic factors that influence the relationship between attention-deficit disorder/attention-deficit/hyperactivity disorder and weight status in children and adolescents.
Universal Screening for Hearing Loss in Newborns: US Preventive Services Task Force Recommendation Statement
Authors:   US Preventive Services Task Force
Published: July 2008

DESCRIPTION. This is the 2008 update of the 2001 US Preventive Services Task Force recommendation on universal newborn hearing screening.

METHODS. The US Preventive Services Task Force weighed the benefits and harms of universal newborn hearing screening, incorporating new evidence addressing gaps identified in the 2001 US Preventive Services Task Force recommendation statement. Published literature on this topic was identified (by using Medline and Cochrane databases) and systematically reviewed.

RECOMMENDATION. Screen for hearing loss in all newborn infants (B recommendation).
Care Coordination for Children and Youth With Special Health Care Needs: A Descriptive, Multisite Study of Activities, Personnel Costs, and Outcomes
Authors: Antonelli Richard C. , Stille Christopher J. , Antonelli Donna M.
Published: July 2008

OBJECTIVES. Objectives included testing use of the care-coordination measurement tool in pediatric primary care practices; describing care-coordination activities for children and youth that occur in primary care practices; assessing the relationship of care-coordination activities in the medical home with outcomes related to resource use; and measuring the direct personnel costs of care-coordination activities.

METHODS. Six general pediatric practices were selected, representing a diverse range of sizes, locations, patient demographics, and care-coordination activity model types. The care-coordination measurement tool was used over a period of 8 months in 2003 to record all of the nonreimbursable care-coordination activity encounters performed by any office-based personnel. The tool enabled recording of activities, resources-use outcomes, and time. Cost of personnel performing care-coordination activities was derived by extrapolation from the time spent.

RESULTS. Care-coordination activity services were used by patients of all complexity levels. Children and youth with special health care needs with acute-onset, family-based psychosocial problems experienced 14% of the care-coordination activity encounters and used 21% of the care-coordination activities minutes. Children and youth without special health care needs, without complicating family psychosocial problems, received 50% of the encounters and used 36% of the care-coordination activity minutes. The average cost per care-coordination activity encounter varied from $4.39 to $12.86, with an overall mean of $7.78. A principal cost driver seemed to be the percentage of care-coordination activities performed by physicians. Office-based nurses prevented a large majority of emergency department visits and episodic office visits.

CONCLUSIONS. Care-coordination activity was assessed at the practice level, and the care-coordination measurement tool was used successfully during the operations of typical, pediatric, primary care settings. The presence of acute, family-based social stressors was a significant driver of need for care-coordination activities. A high proportion of dependence on care-coordination performed by physicians led to increased costs. Office-based nurses providing care coordination were responsible for a significant number of episodes of avoidance of higher cost use outcomes.
Patient Factors Used by Pediatricians to Assign Asthma Treatment
Authors: Okelo Sande O. , Patino Cecilia M. , Riekert Kristin A. , Merriman Barry , Bilderback Andrew , Hansel Nadia N. , Thompson Kathy , Thompson Jennifer , Quartey Ruth , Rand Cynthia S. , Diette Gregory B.
Published: July 2008

OBJECTIVE. Although asthma is often inappropriately treated in children, little is known about what information pediatricians use to adjust asthma therapy. The purpose of this work was to assess the importance of various dimensions of patient asthma status as the basis of pediatrician treatment decisions.

PATIENTS AND METHODS. We conducted a cross-sectional, random-sample survey, between November 2005 and May 2006, of 500 members of the American Academy of Pediatrics using standardized case vignettes. Vignettes varied in regard to (1) acute health care use (hospitalized 6 months ago), (2) bother (parent bothered by the child's asthma status), (3) control (frequency of symptoms and albuterol use), (4) direction (qualitative change in symptoms), and (5) wheezing during physical examination. Our primary outcome was the proportion of pediatricians who would adjust treatment in the presence or absence of these 5 factors.

RESULTS. Physicians used multiple dimensions of asthma status other than symptoms to determine treatment. Pediatricians were significantly more likely to increase treatment for a recently hospitalized patient (45% vs 18%), a bothered parent (67% vs 18%), poorly controlled symptoms (4–5 times per week; 100% vs 18%), or if there was wheezing on examination (45% vs 18%) compared with patients who only had well-controlled symptoms. Pediatricians were significantly less likely to decrease treatment for a child with well-controlled symptoms and recent hospitalization (28%), parents who reported being bothered (43%), or a child whose symptoms had worsened since the last doctor visit (10%) compared with children with well-controlled symptoms alone.

CONCLUSIONS. Pediatricians treat asthma on the basis of multiple dimensions of asthma status, including hospitalization, bother, symptom frequency, direction, and wheezing but use these factors differently to increase and decrease treatment. Tools that systematically assess multiple dimensions of asthma may be useful to help further improve pediatric asthma care.
Implementation of Rotavirus Immunization in Philadelphia, Pennsylvania: High Levels of Vaccine Ineligibility and Off-Label Use
Authors: Daskalaki Irini , Spain C. Victor , Long Sarah S. , Watson Barbara
Published: July 2008

OBJECTIVE. Our goal was to predict, using delayed diphtheria-tetanus-acellular pertussis vaccination as an indicator, whether the current narrowly defined age limits for pentavalent rotavirus vaccine exclude a substantial proportion of children from complete immunization against rotavirus and to assess adherence of providers to recommended age limits by examining the first 6 months of use of pentavalent rotavirus vaccine in Philadelphia, Pennsylvania.

PATIENTS AND METHODS. Data from a computerized children's immunization registry in Philadelphia were analyzed. Demographics and age at immunization with first 3 diphtheria-tetanus-acellular pertussis doses were examined from 2001 to 2005. Similar characteristics were evaluated for children who received pentavalent rotavirus vaccine doses during the first 6 months of its availability (August 2006 through January 2007).

RESULTS. During the 5-year period, 24 403 of 103 967 recipients of first diphtheria-tetanus-acellular pertussis vaccine were >12 weeks of age; only 56 411 of 79 564 first diphtheria-tetanus-acellular pertussis recipients ≤12 weeks of age received the first 3 doses at ages that they could have completed the pentavalent rotavirus vaccine series if vaccines were given at the same visit. Children using public providers were more likely to have delayed immunization. During the first 6 months of pentavalent rotavirus vaccine implementation, 5566 pentavalent rotavirus vaccine doses were recorded in the Kids Immunization Database/Tracking System: 3912 first doses, 1419 second doses, and 235 third doses. Of 3912 first-dose pentavalent rotavirus vaccine recipients, 770 were >12 weeks of age. Hospital-based providers were less likely to administer pentavalent rotavirus vaccine off-label.

CONCLUSIONS. With the current level of vaccine implementation and current pentavalent rotavirus vaccine recommendations for series initiation, a substantial proportion of children are expected to be excluded from receiving any pentavalent rotavirus vaccine or completing the series. In the first 6 months of availability, pentavalent rotavirus vaccine frequently was used off-label for age, underscoring the importance of education of immunization providers. Current outreach programs for finding 10-month-old toddlers delinquent for immunizations will not improve the possibility of protection against rotavirus.
Is Office-Based Counseling About Media Use, Timeouts, and Firearm Storage Effective? Results From a Cluster-Randomized, Controlled Trial
Authors: Barkin Shari L. , Finch Stacia A. , Ip Edward H. , Scheindlin Benjamin , Craig Joseph A. , Steffes Jennifer , Weiley Victoria , Slora Eric , Altman David , Wasserman Richard C.
Published: July 2008

OBJECTIVE. The objective of this study was to determine whether patients' families' violence-prevention behaviors would be affected by their primary care practitioner's use of a violence-prevention clinical intervention during the routine well-child examination.

METHODS. In this cluster-randomized, controlled trial (2002–2006), 137 Pediatric Research in Office Settings practices were randomly assigned and initiated patient recruitment for either an office-based violence-prevention intervention or a control group (educational handout on literacy promotion provided). Primary caregivers of children who were aged 2 to 11 years and presented for a well-child visit were surveyed at baseline and 1 and 6 months. Practitioners were trained to (1) review a parent previsit summary regarding patient-family behavior and parental concern about media use, discipline strategies, and children's exposure to firearms, (2) counsel using brief principles of motivational interviewing, (3) identify and provide local agency resources for anger and behavior management when indicated, and (4) instruct patient-families on use of tangible tools (minute timers to monitor media time/timeouts and firearm cable locks to store firearms more safely where children live or play). Main outcomes were change over time in self-reported media use <120 minutes per day, use of timeouts, and use of firearm cable locks.

RESULTS. Generalized estimating equation analysis revealed a significant effect at 6 months for decreased media use and safer firearm storage. The intervention group compared with the control group showed an increase in limiting media use to <120 minutes per day. There was no significant effect for timeout use. There was a substantial increase in storing firearms with cable locks for the intervention group versus a decrease for the control group.

CONCLUSIONS. This randomized, controlled trial demonstrated decreased media exposure and increased safe firearm storage as a result of a brief office-based violence-prevention approach.
Community-wide Intervention to Improve the Attention-Deficit/Hyperactivity Disorder Assessment and Treatment Practices of Community Physicians
Authors: Epstein Jeffery N. , Langberg Joshua M. , Lichtenstein Philip K. , Mainwaring Beth A. , Luzader Carolyn P. , Stark Lori J.
Published: July 2008

OBJECTIVES. The goals were to implement and to test a quality-improvement intervention aimed at improving community-based primary care providers’ adherence to the American Academy of Pediatrics, evidence-based diagnostic and treatment guidelines for attention-deficit/hyperactivity disorder.

METHODS. Nineteen practices (with 84 primary care providers) from a large urban community were trained by using quality-improvement methods with some academic detailing. Pretraining and posttraining adherence to evidence-based practices was assessed through review of patient charts.

RESULTS. Preintervention rates of guideline usage were uniformly low. After the intervention, primary care providers showed substantial improvement in their use of the guidelines for the assessment and treatment of elementary school-aged patients with newly diagnosed attention-deficit/hyperactivity disorder. Use of parent and teacher assessment rating scales increased from levels of 52% to 55% to levels of nearly 100%. Systematic monitoring of responses to medication improved from a baseline level of 9% to 40%.

CONCLUSIONS. Quality-improvement interventions such as the one used in this study seem quite effective in improving primary care providers’ practices at offices that express interest in improving the quality of care for attention-deficit/hyperactivity disorder. The design of the intervention, problems associated with improving and sustaining treatment monitoring, and issues related to generalizability of the intervention model are discussed.