bluuebunny/crossref_metadata_2025 huggingface dataset:
Cord Blood Leptin and Adiponectin as Predictors of Adiposity in Children at 3 Years of Age: A Prospective Cohort Study
Authors: Mantzoros Christos S. , Rifas-Shiman Sheryl L. , Williams Catherine J. , Fargnoli Jessica L. , Kelesidis Theodoros , Gillman Matthew W.
Published: January 2009

OBJECTIVES. Leptin and adiponectin are adipocyte-secreted hormones that regulate energy homeostasis and metabolism. Because their roles in the neonatal period and in early childhood are poorly understood, we aimed in this prospective cohort study to determine the extent to which umbilical cord blood leptin and adiponectin concentrations predict measures of adiposity and growth at 3 years of age.

PATIENTS AND METHODS. We studied 588 children participating in the prospective prebirth cohort study Project Viva. We examined associations of cord blood leptin and adiponectin levels with weight changes during the first 6 months of life, 3-year circulating leptin and adiponectin concentrations, and the following adiposity-related outcomes at 3 years of age: BMI z score, height-for-age z score, and sums of triceps and subscapular skinfold thicknesses to represent overall adiposity, as well as subscapular/triceps skinfold ratio to represent central adiposity.

RESULTS. Cord blood leptin and adiponectin were each directly associated with the duration of gestation and birth weight for gestational age z scores. Cord blood leptin levels were negatively associated with change in weight-for-length, weight-for-age, and length-for-age z scores between birth and 6 months of age. Similarly, cord blood adiponectin was negatively associated with change in weight-for-length and weight-for-age z scores. After adjusting for several maternal and child factors related to obesity, each 10 ng/mL increment of cord blood leptin was associated with a reduction in BMI z score and higher leptin levels at 3 years but not with skinfold thicknesses. Each 10 μg/mL increment of cord blood adiponectin was positively associated with a higher subscapular skinfold thickness/triceps skinfold thickness ratio at 3 years.

CONCLUSIONS. Lower cord blood leptin levels are associated with smaller size at birth but more pronounced weight gain in the first 6 months of life and higher BMI at 3 years of age. Cord blood adiponectin levels are also directly associated with birth weight for gestational age, inversely associated with weight gain in the first 6 months of life, and predict an increase in central adiposity at age 3 years.
Prenatal Alcohol Exposure and Language Delay in 2-Year-Old Children: The Importance of Dose and Timing on Risk
Authors: O'Leary Colleen , Zubrick Stephen R. , Taylor Catherine L. , Dixon Glenys , Bower Carol
Published: January 2009

OBJECTIVE. The aim of this study was to investigate the association of dose and timing of prenatal alcohol exposure with early language acquisition.

METHODS. We examined language delay in a randomly selected, population-based sample of Western Australian children born in 1995–1996 whose mothers had agreed to participate in a longitudinal study on health-related behaviors and who had completed the 2-year questionnaire (N = 1739). Information on alcohol consumption was collected at 3 months after birth for four periods; the three months pre-pregnancy and for each trimester separately. Prenatal alcohol exposure was grouped into none, low, moderate-heavy and binge (>5) based on the total quantity consumed per week, quantity consumed per occasion, and frequency of consumption. The communication scale from the Ages & Stages Questionnaire was used to evaluate language delay. Logistic regression analysis was used to generate odds ratios and 95% confidence intervals, adjusted for confounding factors.

RESULTS. There was no association between low levels of alcohol consumption and language delay at any time period, although there was a nonsignificant 30% increase in risk when moderate-to-heavy levels of alcohol were consumed in the third trimester. Children exposed to a binge pattern of maternal alcohol consumption in the second trimester had nonsignificant, three-fold increased odds of language delay, with a similar estimate following third trimester alcohol exposure after controlling for covariates.

CONCLUSIONS. This study did not detect an association between low levels of prenatal alcohol exposure and language delay when compared with women who abstained from alcohol during pregnancy. A nonsignificant threefold increase in the likelihood of language delay was seen in children whose mothers binged during late pregnancy. However, the small numbers of women with a binge-drinking pattern in late pregnancy limited the power of this study; studies analyzing larger numbers of children exposed to binge drinking in late pregnancy are needed.
Parenting Behavior Is Associated With the Early Neurobehavioral Development of Very Preterm Children
Authors: Treyvaud Karli , Anderson Vicki A. , Howard Kelly , Bear Merilyn , Hunt Rod W. , Doyle Lex W. , Inder Terrie E. , Woodward Lianne , Anderson Peter J.
Published: January 2009

OBJECTIVE. There is an increasing focus on social and environmental factors that promote and support the early development of highly vulnerable children such as those born very preterm. The aim of this study was to assess the relationship between parenting behavior, parent-child synchrony, and neurobehavioral development in very preterm children at 24 months of age.

METHODS. Participants were 152 very preterm children (<30 weeks’ gestation or <1250 g birth weight) and their parents/guardians. At 2 years’ corrected age, parents/guardians and children completed a semistructured parent-child interaction task assessing dyad synchrony and parenting behavior (positive affect, negative affect, sensitivity, facilitation, and intrusiveness). Cognitive and motor development was assessed by using the Bayley Scales of Infant Development II, and the Infant Toddler Social and Emotional Assessment was used to assess socioemotional development (social-emotional competence and internalizing and externalizing behavior).

RESULTS. After controlling for social risk, most parenting domains were associated with cognitive development, with parent-child synchrony emerging as the most predictive. Greater parent-child synchrony was also associated with greater social-emotional competence, as was parenting that was positive, warm, and sensitive. Parents who displayed higher levels of negative affect were more likely to rate their children as withdrawn, anxious, and inhibited, but, unexpectedly, higher negative affect was also associated with more optimal psychomotor development. Parenting was not associated with externalizing behaviors at this age.

CONCLUSIONS. Specific parenting behaviors, particularly parent-child synchrony, were associated with neurobehavioral development. These findings have implications for the development of targeted parent-based interventions to promote positive outcomes across different developmental domains during the first 2 years of life for very preterm children.
Economic Evaluation of Tandem Mass Spectrometry Newborn Screening in Australia
Authors: Norman Richard , Haas Marion , Chaplin Meredyth , Joy Pamela , Wilcken Bridget
Published: January 2009

OBJECTIVE. The goal was to investigate the cost-effectiveness of tandem mass spectrometry screening for the detection of inborn metabolic errors in an Australian setting.

METHODS. Cost-effectiveness analysis from the health service perspective was undertaken on the basis of registry data for affected individuals. The intervention group was contrasted with both a contemporaneous group in nonscreening states and a historical cohort. The registry covers all individuals identified in Australia between 1994 and 2002. Main outcome measures were the total net cost of screening, the cost of treatment, life-years saved, and deaths averted.

RESULTS. The total net cost of testing was estimated to be A$218 000 per 100 000 infants. Medical costs incurred by the intervention group exceeded those for the control group by A$131 000 per 100 000 infants. The number of life-years saved per 100 000 infants screened was 32.378 life-years per 100 000 infants through an expected mortality rate reduction of 0.738 deaths per 100 000 infants. The cost per death averted was estimated to be A$472 913 and the cost per life-year saved was estimated to be A$10 779, which compare favorably with existing cost-effectiveness standards. This conclusion is particularly robust because conservative assumptions were made throughout, because of data limitations. Sensitivity analyses suggested that this result was relatively robust to adjustment of model parameters.

CONCLUSIONS. Tandem mass spectrometry screening for conditions caused by rare errors of metabolism is likely to be a cost-effective intervention in Australia.
Impact of the 2004–2005 Influenza Vaccine Shortage on Pediatric Practice: A National Survey
Authors: McQuillan Lon , Daley Matthew F. , Stokley Shannon , Crane Lori A. , Beaty Brenda L. , Barrow Jennifer , Babbel Christine , Dickinson L. Miriam , Kempe Allison
Published: January 2009

BACKGROUND. A severe influenza vaccine shortage occurred during the 2004–2005 influenza season because of the loss of all vaccine made by Chiron (Emeryville, CA) for US distribution.

OBJECTIVES. The objectives of this study were to assess among pediatricians nationally: (1) influenza vaccine-delivery strategies; (2) reported vaccine shortages and factors associated with experiencing shortages; and (3) the impact of shortages on vaccine redistribution, patient referral, and clinical practice, including patient prioritization.

METHODS. A survey was administered in March 2005 through June 2005 to 427 pediatricians who participated in a national network representative of the American Academy of Pediatrics membership.

RESULTS. Our response rate was 82%. Thirty-nine percent of the pediatricians had a computerized method for identifying patients at high risk needing vaccination. Ninety-four percent and 79% reported giving high-priority to children ≥24 months old with high-risk conditions and children 6 to 23 months old, respectively, whereas 41% gave high-priority to household contacts and caregivers of children <6 months old. Forty-three percent reported experiencing shortages of vaccine for patients at high risk, whereas only 14% ordered Chiron vaccine. In multivariate analyses, ordering vaccine from Chiron and ordering Aventis Pasteur (Lyon, France) vaccine solely from a vaccine distributor were associated with experiencing a shortage. Forty-eight percent of respondents obtained additional vaccine from another source, most frequently the public health sector, whereas 37% reported selling or giving away vaccine. In addition, 47% referred patients at high risk elsewhere for vaccination, primarily to public health clinics. Forty-nine percent reported having unused vaccine remaining at the end of the season.

CONCLUSIONS. Although few pediatricians ordered Chiron vaccine, substantial influenza vaccine shortages were reported, highlighting the tenuousness of injectable influenza vaccine supplies for children. The extensive redistribution of vaccine suggests that cooperative efforts between the private and public sectors were widespread. Efforts to vaccinate patients at high risk during shortages would be aided by better systems to identify and recall these patients.
Clinical Inactivity Among Pediatricians: Prevalence and Perspectives
Authors: Freed Gary L. , Dunham Kelly M. , Switalski Kara E.
Published: January 2009

INTRODUCTION. During their careers, physicians may have periods of clinical inactivity for a variety of reasons. Concerns have been raised about the impact of clinical inactivity on the growing physician workforce shortage. It is unknown how these periods of clinical inactivity impact physician competence and patient safety. With this study we sought to determine the rates of clinical inactivity, the duration of periods of inactivity, professional activities during those periods, and the perspective of pediatricians regarding future requirements of competency for return to clinical practice.

PATIENTS AND METHODS. A random sample of 6757 American Board of Pediatrics diplomates aged ≤65 years received a structured questionnaire by mail. The survey explored the prevalence of and reasons for clinical inactivity and perspectives on the return to clinical practice. Clinical inactivity was defined as a period of absence of ≥12 months from any direct or consultative clinical care.

RESULTS. The response rate was 74%. Of respondents, 88% (n = 4176) were currently engaged in pediatric clinical care. Twelve percent (n = 554) indicated that they had experienced a period of clinical inactivity lasting ≥12 months. Women were more likely than men (16% vs 7%) to have had periods of clinical inactivity. Controlling for gender, generalists were no more likely than subspecialists to report a past period of clinical inactivity. More than one third of the respondents (n = 1672 [36%]) agreed that pediatricians who return from clinical inactivity after >1 year should undergo a competency evaluation.

CONCLUSIONS. Almost 1 in 8 pediatricians has suspended clinical care for ≥1 year, and a similar proportion of respondents were inactive at the time of our survey. Currently, all of these physicians may maintain both their licensure and board certification during these periods. The impact of clinical inactivity on patient care and patient safety is unknown.
Genetic Contribution to Patent Ductus Arteriosus in the Premature Newborn
Authors: Bhandari Vineet , Zhou Gongfu , Bizzarro Matthew J. , Buhimschi Catalin , Hussain Naveed , Gruen Jeffrey R. , Zhang Heping
Published: January 2009

BACKGROUND. The most common congenital heart disease in the newborn population, patent ductus arteriosus, accounts for significant morbidity in preterm newborns. In addition to prematurity and environmental factors, we hypothesized that genetic factors play a significant role in this condition.

OBJECTIVE. The objective of this study was to quantify the contribution of genetic factors to the variance in liability for patent ductus arteriosus in premature newborns.

PATIENTS AND METHODS. A retrospective study (1991–2006) from 2 centers was performed by using zygosity data from premature twins born at ≤36 weeks' gestational age and surviving beyond 36 weeks' postmenstrual age. Patent ductus arteriosus was diagnosed by echocardiography at each center. Mixed-effects logistic regression was used to assess the effect of specific covariates. Latent variable probit modeling was then performed to estimate the heritability of patent ductus arteriosus, and mixed-effects probit modeling was used to quantify the genetic component.

RESULTS. We obtained data from 333 dizygotic twin pairs and 99 monozygotic twin pairs from 2 centers (Yale University and University of Connecticut). Data on chorioamnionitis, antenatal steroids, gestational age, body weight, gender, respiratory distress syndrome, patent ductus arteriosus, necrotizing enterocolitis, oxygen supplementation, and bronchopulmonary dysplasia were comparable between monozygotic and dizygotic twins. We found that gestational age, respiratory distress syndrome, and institution were significant covariates for patent ductus arteriosus. After controlling for specific covariates, genetic factors or the shared environment accounted for 76.1% of the variance in liability for patent ductus arteriosus.

CONCLUSIONS. Preterm patent ductus arteriosus is highly familial (contributed to by genetic and environmental factors), with the effect being mainly environmental, after controlling for known confounders.
Effect of Cell Phone Distraction on Pediatric Pedestrian Injury Risk
Authors: Stavrinos Despina , Byington Katherine W. , Schwebel David C.
Published: January 2009

OBJECTIVE. Early adolescents are using cell phones with increasing frequency. Cell phones are known to distract motor vehicle drivers to the point that their safety is jeopardized, but it is unclear if cell phones might also distract child pedestrians. This study was designed to examine the influence of talking on a cell phone for pediatric pedestrian injury risk.

PARTICIPANTS AND METHODS. Seventy-seven children aged 10 to 11 years old completed simulated road crossings in an immersive, interactive virtual pedestrian environment. In a within-subjects design, children crossed the virtual street 6 times while undistracted and 6 times while distracted by a cell phone conversation with an unfamiliar research assistant. Participants also completed several other experimental tasks hypothesized to predict the impact of distraction while crossing the street and talking on a cell phone.

RESULTS. Children's pedestrian safety was compromised when distracted by a cell phone conversation. While distracted, children were less attentive to traffic; left less safe time between their crossing and the next arriving vehicle; experienced more collisions and close calls with oncoming traffic; and waited longer before beginning to cross the street. Analyses testing experience using a cell phone and experience as a pedestrian yielded few significant results, suggesting that distraction on the cell phone might affect children's pedestrian safety no matter what their experience level. There was some indication that younger children and children who are less attentive and more oppositional may be slightly more susceptible to distraction while talking on the cell phone than older, more attentive, and less oppositional children.

CONCLUSION. Our results suggest that cell phones distract preadolescent children while crossing streets.
Clarification of Laboratory and Clinical Variables That Influence Cystic Fibrosis Newborn Screening With Initial Analysis of Immunoreactive Trypsinogen
Authors: Kloosterboer Molly , Hoffman Gary , Rock Michael , Gershan William , Laxova Anita , Li Zhanhai , Farrell Philip M.
Published: January 2009

OBJECTIVES. To ensure that each newborn receives an equitable test of the highest possible sensitivity, we recognized the necessity to reassess immunoreactive trypsinogen and DNA issues in cystic fibrosis newborn screening algorithms. Our objectives included clarification of various factors that influence immunoreactive trypsinogen concentrations and resolution of long-standing questions about variations in immunoreactive trypsinogen levels among newborns.

METHODS. Immunoreactive trypsinogen data on 660443 newborns who were born between July 1, 1994, and June 30, 2004, were abstracted from the Wisconsin State Laboratory of Hygiene databases and deidentified for analysis. Using a compiled data set, we analyzed various demographic characteristics to determine their role, if any, in immunoreactive trypsinogen variation. Specifically, season of birth, reagent lot, and birth weight were examined. Sensitivities of the most common cystic fibrosis newborn screening protocols, namely immunoreactive trypsinogen/immunoreactive trypsinogen and immunoreactive trypsinogen/DNA, were also investigated.

RESULTS. Mean and 95th percentile immunoreactive trypsinogen levels were shown to vary by both season and reagent lot number and affect sensitivity of the assay. Low birth weight infants had significantly higher immunoreactive trypsinogen values than normal birth weight infants. Sensitivities were also found to vary on the basis of the algorithm used, with the highest sensitivity of 96.2% calculated for an immunoreactive trypsinogen/DNA protocol with 23 cystic fibrosis transmembrane conductance regulator mutation analyses compared with 80.2% with the immunoreactive trypsinogen/immunoreactive trypsinogen method used in 9 states.

CONCLUSIONS. Floating, rather than fixed, cutoff values for the initial immunoreactive trypsinogen portion of any cystic fibrosis newborn screening protocol are generally necessary on the basis of the seasonal and reagent lot variations observed. Because of its lower sensitivity, immunoreactive trypsinogen/immunoreactive trypsinogen does not optimize detection of patients with cystic fibrosis.
Who Will Speak for Me? Improving End-of-Life Decision-Making for Adolescents With HIV and Their Families
Authors: Lyon Maureen E. , Garvie Patricia A. , McCarter Robert , Briggs Linda , He Jianping , D'Angelo Lawrence J.
Published: January 2009

OBJECTIVES. The purpose of this research was to test the effectiveness of a model of family/adolescent-centered advance care planning for adolescents living with HIV and their families for increasing congruence and quality of communication while decreasing decisional conflict.

PATIENTS AND METHODS. Ours was a 2-group, randomized, controlled trial in 2 hospital-based outpatient clinics in Washington and Memphis from 2006 to 2008. Participants (N = 38 dyads) included medically stable adolescents aged 14 to 21 years with HIV/AIDS and surrogates/families aged ≥21 years. Three 60- to 90-minute sessions were conducted 1 week apart via a semistructured family interview with a trained/certified interviewer. Each session encompassed, respectively: (1) Lyon Advance Care Planning Survey; (2) Respecting Choices interview; and (3) Five Wishes. Controls received (1) developmental history, (2) safety tips, and (3) future plans. Family congruence was measured by the Statement of Treatment Preferences and adolescent decisional conflict by the Decisional Conflict Scale, immediately after session 2. Communication was measured by the Quality of Participant-Interviewer Communication Scale after each session.

RESULTS. Adolescent demographics were as follows: mean age was 16 years; 40% were boys; 92% were black; HIV transmission rate was 68% perinatal and 32% sexually acquired; 42% were asymptomatic; 29% were symptomatic; and 29% had a diagnosis of AIDS. Significantly increased congruence for testing the difference of the 2 κ values for the 2 conditions was observed for intervention versus control dyads. Intervention adolescents reported feeling significantly better informed about end-of-life decisions. Intervention adolescents and all of the surrogates were more likely to feel that their attitudes and wishes were known by the interviewer over time. Intervention families, significantly more so than controls, rated the overall quality of discussion as very good to excellent.

CONCLUSIONS. Family-centered advance care planning by trained facilitators increased congruence in adolescent/surrogate preferences for end-of-life care, decreased decisional conflict, and enhanced communication quality. Families acknowledged a life-threatening condition and were willing to initiate end-of-life conversations when their adolescents were medically stable.
Skeletal Surveys in Infants With Isolated Skull Fractures
Authors: Wood Joanne N. , Christian Cindy W. , Adams Cynthia M. , Rubin David M.
Published: January 2009

OBJECTIVE. The goal was to describe the utility of skeletal surveys and factors associated with both skeletal survey use and referral to child protective services for infants with skull fractures in the absence of significant intracranial injury.

METHODS. A retrospective chart review was performed for infants who were evaluated at a tertiary children's hospital because of an isolated, non–motor vehicle-related, skull fracture between 1997 and 2006. Logistic regression analyses were used to test for associations of demographic factors, clinical findings that raised suspicion for abuse (absence of trauma history, changing history, delay in care, previous child protective services involvement, and other cutaneous injuries), and fracture type (simple versus complex) with the primary outcomes of skeletal survey use and reports to child protective services.

RESULTS. Among the 341 infants in the study, 31% had clinical findings that raised suspicion for abuse and 42% had complex skull fractures. Skeletal surveys were obtained for 141 infants (41%) and detected additional fractures for only 2 (1.4%) of those 141 infants. Child protective services reports were made for 52 (15%) of the 341 children. Both infants with positive skeletal survey findings had other clinical findings that raised suspicion for abuse, and they were among those reported. With controlling for race and age, Medicaid-eligible/uninsured infants were more likely than privately insured infants to receive skeletal surveys and child protective services reports in the presence of a complex skull fracture or clinical findings that raised suspicion for abuse.

CONCLUSION. Skeletal surveys were ordered frequently for infants with isolated skull fractures, but they rarely added additional information, beyond the history and physical findings, to support a report to child protective services.
Reference Ranges for Hematocrit and Blood Hemoglobin Concentration During the Neonatal Period: Data From a Multihospital Health Care System
Authors: Jopling Jeffery , Henry Erick , Wiedmeier Susan E. , Christensen Robert D.
Published: January 2009

OBJECTIVE. “Reference ranges” are developed when it is impossible or inappropriate to establish “normal ranges” by drawing blood on healthy normal volunteers. Reference ranges for the hematocrit and the blood hemoglobin concentration of newborn infants have previously been reported from relatively small sample sizes by using measurement methods that now are considered outmoded.

METHODS. We sought to develop reference ranges for hematocrit and hemoglobin during the neonatal period (28 days) by using very large sample sizes and modern hematology analyzers, accounting for gestational and postnatal age and gender. Data were assembled from a multihospital health care system after exclusion of patients with a high likelihood of an abnormal value and those who were receiving blood transfusions.

RESULTS. During the interval from 22 to 40 weeks' gestation, the hematocrit and blood hemoglobin concentration increased approximately linearly. For every week advance in gestational age, the hematocrit increased by 0.64% and the hemoglobin concentration increased by 0.21 g/dL. No difference was seen on the basis of gender. During the 4-hour interval after birth, hematocrit/hemoglobin values of late preterm and term neonates (35–42 weeks' gestation) increased by 3.6% ± 0.5% (mean ± SD), those of neonates of 29 to 34 weeks' gestation remained unchanged, and those of <29 weeks' gestation decreased by 6.0% ± 0.3%. During the first 28 days after birth, an approximately linear decrease in hematocrit/hemoglobin occurred.

CONCLUSIONS. The figures presented herein describe reference ranges for hematocrit and blood hemoglobin concentration during the neonatal period, accounting for gestational and postnatal age.
The Role of Preschool Home-Visiting Programs in Improving Children's Developmental and Health Outcomes
Authors:   Council on Community Pediatrics
Published: January 2009

Child health and developmental outcomes depend to a large extent on the capabilities of families to provide a nurturing, safe environment for their infants and young children. Unfortunately, many families have insufficient knowledge about parenting skills and an inadequate support system of friends, extended family, or professionals to help with or advise them regarding child rearing. Home-visiting programs offer a mechanism for ensuring that at-risk families have social support, linkage with public and private community services, and ongoing health, developmental, and safety education. When these services are part of a system of high-quality well-child care linked or integrated with the pediatric medical home, they have the potential to mitigate health and developmental outcome disparities. This statement reviews the history of home visiting in the United States and reaffirms the support of the American Academy of Pediatrics for home-based parenting education and support.
Spark plasma sintering of zirconium carbide and oxycarbide: Finite element modeling of current density, temperature, and stress distributions
Authors: Antou Guy , Mathieu Gendre , Trolliard Gilles , Maître Alexandre
Published: January 2009

A combined experimental/numerical approach was developed to determine the distribution of current density, temperature, and stress arising within the sample during spark plasma sintering (SPS) treatment of zirconium carbide (ZrCx) or oxycarbide (ZrCxOy). Stress distribution was calculated by using a numerical thermomechanical model, assuming that a slip without mechanical friction exists at the interfaces between the sample and the graphite elements. Heating up to 1950 °C at 100 °C min−1 and a constant applied pressure of 100 MPa were retained as process conditions. Simulated temperature distributions were found to be in excellent agreement with those measured experimentally. The numerical model confirms that, during the zirconium oxycarbide sintering, the temperature measured by the pyrometer on the die surface largely underestimates the actual temperature of the sample. This real temperature is in fact near the optimized sintering temperature for hot-pressed zirconium oxycarbide specimens. It is also shown that high stress gradients existing within the sample are much higher than the thermal ones. The amplitude of the stress gradients was found to be correlated with those of temperature even if they are also influenced by the macroscopic sample properties (coefficient of thermal expansion and elastic modulus). At high temperature, the radial and angular stresses, which are much higher than the vertical applied stress, provide the more significant contribution to the stress-related driving force for densification during the SPS treatment. The heat lost by radiation toward the wall chambers controlled both the thermal and stress gradients.
A new solder wetting layer for Pb-free solders
Authors: Oh Chang Yul , Roh Hee-Ra , Kim Young Min , Lee Jin Soo , Cho Hae Young , Kim Young-Ho
Published: January 2009

We developed a new Cu–Zn wetting layer for Pb-free solders. By adding Zn to the Cu wetting layer, intermetallic growth in the Sn–Ag–Cu (SAC) solder interfaces was delayed. Cu3Sn intermetallic compounds and microvoids were not observed in the SAC/Cu–Zn interfaces after aging. The drop reliability of the SAC solder/Cu–Zn joints was excellent.
Nanopatterned optical and magnetic La0.6Ca0.4MnO3 arrays: Synthesis, fabrication, and properties
Authors: Wu Ming-Chung , Chuang Chih-Min , Lin Jhih-Fong , Huang Yu-Ching , Chen Yang-Fang , Su Wei-Fang
Published: January 2009

We have fabricated La0.6Ca0.4MnO3 periodic arrays exhibiting tunable optical properties and magnetic properties using nontoxic and environmentally friendly electron beam resist made from La0.6Ca0.4MnO3 sol-gel precursor. We studied their unique optical properties by using the spectral microreflectometer and their magnetic properties using the superconducting quantum interference device and magnetic force microscopy. Additionally, the resist has the ability to demonstrate both positive and negative resist behaviors depending on the electron beam dosage. With these special characteristics, we can fabricate periodic structure on a thin film possessing controlled optical reflectance properties with one fixed design electron beam pattern without changing the structural parameters but changing the electron beam dosage only. Our approach provides an uncomplicated route for the fabrication of nanometer scale magnetic patterns, which serve as the building blocks in the search for novel properties of periodic magnetic arrays.
The influence of prior cold deformation on precipitation of alpha phase and variation of hardness in Ti-10Mo-8V-1Fe-3.5Al during aging treatment
Authors: Song Z.Y. , Sun Q.Y. , Xiao L. , Liu L. , Wang H. , Chen W. , Sun J. , Ge P.
Published: January 2009

The influence of prior cold deformation on precipitating of alpha phase as well as the variation of hardness during aging has been investigated in solution-treated Ti-10Mo-8V-1Fe-3.5Al alloys. The results show that alpha phase precipitation could be obviously accelerated by the prior cold deformation. In the predeformed samples, a network pattern structure was observed with an optical microscope after aging treatment. It could be attributed to the phenomenon that the plate-shape alpha precipitates prefer to nucleate and grow in the regions with a high density of dislocations, especially inside slip bands. The hardness of both the predeformed and undeformed TB3 specimens after different aging times was measured and further predicted by a proposed strengthening model based on the grain refinement mechanism of the beta phase. The predicted results are consistent with the experimental results, especially in the later aging stages.
Serrated flow behavior induced by blunt mechanism of shear crack propagation in metallic glass
Authors: Fan J.T. , Zhang Z.F. , Mao S.X. , Shen B.L. , Eckert J.
Published: January 2009

We present a blunt mechanism to explain the serrated flow behavior and slight “work hardening” at the beginning of yielding during the compression of metallic glass, which is in line with the piling-up of parallel shear bands on the fracture surface with a gradually increasing space from the edge of surface to inside. Meanwhile, two intrinsic parameters, i.e., strength intensity of blunt behavior, , and global work-hardening sensitivity exponent, , are introduced to characterize the blunt effect on the net increase in flow stress or work-hardening behavior of metallic glass.
Growth and assembly of monodisperse Ag nanoparticles by exchanging the organic capping ligands
Authors: Hao Chenhui , Wang Dingsheng , Zheng Wen , Peng Qing
Published: January 2009

Nearly monodisperse Ag nanoparticles capped with octadecylamine were prepared by direct thermal decomposition of silver nitrate in octadecylamine. Then the “oriented attachment” assembly process of these monodisperse nanoparticles was exhibited by exchanging the organic capping ligands, and Ag short nanorods capped with dodecanethiol could be obtained as a result. The composition of Ag was analyzed by x-ray diffraction, and the morphological change from nanoparticle to short-nanorod was examined by transmission electron microscopy. Moreover, we also propose a probable mechanism for this transformation process.
Parâmetros biométricos e produtividade da cana-de-açúcar após tombamento dos colmos
Authors: Carlin Samira Domingues , Silva Marcelo de Almeida , Rossetto Raffaella
Published: January 2009

Os efeitos do tombamento dos colmos à produtividade da cana-de-açúcar são do interesse de pesquisadores em diversas regiões do mundo; no Brasil, entretanto, essa pesquisa é escassa. O objetivo deste trabalho foi avaliar os efeitos causados pelo tombamento e o aparecimento de brotões em parâmetros biométricos e na produtividade de duas variedades de cana-de-açúcar. O experimento foi desenvolvido no município de Jaú (SP), no período de março de 2003 a setembro de 2004. O delineamento experimental foi o de blocos ao acaso, em fatorial com quatro tratamentos (duas variedades e dois manejos de condução da cultura) em quatro repetições. Os manejos consistiram de plantas mantidas eretas e de plantas sujeitas ao tombamento dos colmos. Avaliaram-se dados biométricos e quantificaram-se brotões aos 5, 50, 95, 140 e 185 dias após o tombamento (DAT). Os valores de comprimento e números de colmos foram aumentados pelo tombamento até 95 DAT, mas a emissão de brotões foi favorecida, com conseqüente aumento da produtividade agrícola das variedades. Esses resultados são indicativos de que a colheita de colmos deve ser realizada após 95 dias do tombamento das plantas a fim de se evitar excesso de brotões na matéria-prima.
Resistência à ferrugem da folha e potencial produtivo em genótipos de trigo
Authors: Felicio João Carlos , Camargo Carlos Eduardo de Oliveira , Chaves Márcia Soares , Castro Jairo Lopes de
Published: January 2009

Foram avaliados 18 genótipos de trigo provenientes de cruzamentos entre a linhagem BH1146//AA"S"/WIN"S", oriunda de cruzamentos interespecíficos entre Triticum aestivum L. e Triticum durum L., e as cultivares IAC 289 e IAC 1004, em experimentos instalados em condições de sequeiro em Manduri (Zona A); Capão Bonito e Itapeva (Zona B) e Paranapanema (Zona C), no período de 2003 a 2005. As avaliações dos genótipos ao agente causal da ferrugem da folha foram feitas no estádio de plântulas em casa de vegetação, onde os genótipos foram submetidos à inoculação, individualmente, com esporos de 12 raças de Puccinia triticina, as quais representavam o espectro de virulência do patógeno ocorrente no Brasil e sob infecção natural no campo. Foram avaliados os rendimentos de grãos de cada genótipo nas diferentes regiões e no conjunto dos experimentos, bem como a estabilidade e adaptabilidade. Os genótipos 8 (BH1146//AA"S"/WIN"S"/3/BUC/FKL//MYNA/VUL), 12 e 14 (BH1146//AA"S"/WIN"S"/3/VEE//DOVE/BUC) destacaram-se por sua resistência às raças fisiológicas de Puccinia triticina em casa de vegetação na fase de plântulas. Em condições de infecção natural da doença, destacaram-se os genótipos 4, 5, 8, 12, 13, 16 e 20 e a cultivar IAC 1004 (T. durum) com resistência à ferrugem da folha no triênio. Os melhores rendimentos de grãos foram obtidos pelos genótipos 8 (BH1146//AA"S"/WIN"S"/3/BUC/FKL//MYNA/VUL), 7 (BH1146//AA"S"/WIN"S"/3/HANN*2/PRL) e 18 (CMH 75.A.66/ SERI/3/BH1146//AA"S"/WIN"S"). O menor foi obtido pelo genótipo 16 (KAUZ/3/ BH1146//AA"S"/WIN"S").
Comportamento de dois genótipos de milho cultivados em sistema de aléias preestabelecido com diferentes leguminosas arbóreas
Authors: Leite Andréia Araújo Lima , Ferraz Junior Altamiro Souza de Lima , Moura Emanoel Gomes de , Aguiar Alana das Chagas Ferreira
Published: January 2009

O cultivo em aléias tem sido recomendado como alternativa para a substituição da agricultura de corte e queima, no trópico úmido, devido à grande capacidade de produção de matéria orgânica e de reciclagem de nutrientes, mas algumas dúvidas quanto à sustentabilidade e à competição interespecífica são persistentes. O objetivo no trabalho foi avaliar a viabilidade da cultura do milho em um sistema de cultivo em aléias de leguminosas arbóreas. O delineamento experimental utilizado foi em blocos casualisados, com quatro repetições dos tratamentos: aléias de sombreiro (Clitoria fairchildiana), ingá (Inga edulis), guandu (Cajanus cajan) e leucena (Leucaena leucocephala) e uma testemunha sem aléias. Foram avaliadas a remobilização de carbono e nitrogênio, massa de grãos, massa de mil grãos e competição interespecífica entre as cultivares de milho e as leguminosas. A produção de grãos foi maior nas parcelas com C. fairchildiana e L. leucocephala. A produtividade do híbrido de milho foi superior à da variedade em todos os tratamentos. A produtividade e a massa de mil grãos de milho não são negativamente afetadas pela distância da linha da leguminosa arbórea. Esse estudo conclui que o sistema de aléias com leguminosas arbóreas é uma alternativa importante ao manejo sustentável dos agroecossistemas no tropico úmido. Além disso, nessa região a produtividade em grãos na cultura do milho é favorecida no sistema de aléias preeestabelecidas com as leguminosas arbóreas sombreiro, ingá e leucena e pela utilização de genótipos eficientes no aproveitamento do nitrogênio, cujo sincronismo entre a liberação e a absorção do N aplicado por meio das leguminosas deve ser aprimorado.
Resistência induzida ao pulgão-gigante-do-pinus (Hemiptera: Aphididae) em plantas de Pinus taeda adubadas com silício
Authors: Camargo Joelma Melissa Malherbe , Moraes Jair Campos , Oliveira Edilson Batista de , Iede Edson Tadeu
Published: January 2009

Este trabalho objetivou avaliar o efeito da aplicação de silício na indução de resistência de Pinus taeda L. ao pulgão-gigante-do-pinus Cinara atlantica (Wilson). Foram realizados testes com chance de escolha em plantas com e sem aplicação de silício, onde foi avaliada a preferência e a capacidade reprodutiva dos afídeos. Os testes foram realizados em laboratório (T: 20ºC; UR: 70%; fotofase: 12 horas), em delineamento experimental inteiramente casualizado, com três tratamentos e dez repetições. Os tratamentos foram: T1 - (sem aplicação de silício); T2 - uma dose de 0,01g de silício e T3 - quatro doses de 0,01g de silício, com intervalos de cinco dias entre as aplicações. As aplicações das doses foram via solo. Vinte dias após a aplicação, realizaram-se os testes de preferência e de capacidade reprodutiva com chance de escolha, utilizando-se como arena placas de Petri com ramos de pinus e gaiolas de PVC com mudas de pinus em tubetes. Em cada arena foram liberados 20 pulgões adultos. As avaliações em placas de Petri foram realizadas aos 40 e 90 minutos e às 4, 12, 18, 24, 36, 48 e 72 horas após a liberação dos insetos; em gaiolas as avaliações foram realizadas no primeiro, segundo, terceiro, quarto e sétimo dia, estendendo-se este período por mais três semanas. A aplicação de silício influenciou negativamente a preferência e a capacidade reprodutiva de C. atlantica.
Oviposição e dispersão de ninfas de Bemisia tabaci biótipo B em genótipos de tomateiro
Authors: Fancelli Marilene , Vendramim José Djair , Lourenção André Luiz
Published: January 2009

Diversos métodos têm sido empregados para avaliar a resistência de plantas a moscas-brancas. Todavia, poucos trabalhos têm sido realizados visando determinar a dispersão de ninfas desses insetos sobre as plantas. O objetivo do presente trabalho foi avaliar a oviposição de B. tabaci biótipo B e a dispersão de suas ninfas em folíolos com e sem exsudatos de genótipos de tomateiro. Foram utilizados sete genótipos de tomateiro: LA716, LA1739, PI134417, LA462, LA1584, 'Santa Clara' e P25 (controle suscetível). A oviposição de B. tabaci biótipo B foi avaliada em gaiolas plásticas (2,8 cm²) fixadas na face abaxial dos folíolos, nas quais foram inseridos dez casais do inseto. Para avaliação da dispersão das ninfas, considerou-se o deslocamento dos insetos além do limite da área ocupada pelas gaiolas. As variáveis observadas foram: mortalidade de adultos 24 horas após a liberação, número de ovos, viabilidade da fase de ovo, período de incubação, número de ninfas e dispersão. Em folíolos com exsudato, LA716, LA1739 e PI134417 provocaram as maiores mortalidades. Adultos mortos nos folíolos desses genótipos ficaram aderidos aos tricomas glandulares, o que provocou redução na oviposição do inseto. Para dispersão, nos folíolos com exsudato, os máximos valores ocorreram nos genótipos LA716, LA462 e P25. Na condição sem exsudato, LA716 promoveu a menor dispersão das ninfas. A presença do exsudato influencia negativamente a sobrevivência e oviposição do inseto. A dispersão das ninfas também é afetada pelo exsudato, embora outros fatores possam ser importantes para o deslocamento do inseto.
Doses de fósforo e zinco na cultura do alho em condições de casa de vegetação
Authors: Büll Leonardo Theodoro , Novello Aline , Corrêa Juliano Corulli , Villas Boas Roberto Lyra
Published: January 2009

A adubação fosfatada promove o aumento de produtividade na cultura do alho, mas doses de fósforo (P) podem proporcionar a deficiência de zinco (Zn) na planta, sobretudo em solos com baixos teores deste micronutriente. O objetivo do trabalho foi verificar o efeito da interação entre P e Zn no solo sobre o desenvolvimento e produção de plantas de alho. Foram instalados três experimentos, cada um com um tipo de solo, em vasos com 17 kg de solo, em casa de vegetação telada. Empregou-se delineamento em blocos casualizados em esquema fatorial com 4 doses de P (0, 100, 200 e 400 mg dm-3) utilizando-se superfosfato triplo e 4 doses de Zn (0, 2,5, 5,0 e 10 mg dm-3) aplicados na forma de ZnSO4.7H2O, ambos incorporados ao solo, com três repetições. A produtividade e o desenvolvimento de plantas de alho foram influenciados, isoladamente, pelas doses de P e Zn, não havendo a interação entre esses nutrientes. Para os solos Neossolo Quartzarênico (NQ) textura arenosa, Latossolo Vermelho Distrófico (LE) textura média e Latossolo Vermelho Distroférrico (LR), textura argilosa, as melhores doses de P para a produção de alho foram de 190, 400 e 400 mg dm-3 e para o Zn de 2,2; 6,5 e 5,1 mg dm-3 respectivamente.
Resposta de soqueiras de cana-de-açúcar à aplicação de nitrogênio em sistema de colheita sem queima
Authors: Prado Renato de Mello , Pancelli Márcio Alexandre
Published: January 2009

São restritas as informações sobre a resposta de soqueiras de cana-de-açúcar à aplicação de nitrogênio em colheita sem a despalha a fogo. Diante deste contexto, objetivou-se avaliar a nutrição nitrogenada em soqueiras de cana-de-açúcar, em sistema de colheita sem queima, através de análises químicas do solo, da diagnose foliar, de avaliações biológicas (altura da planta, diâmetro de colmos e número de colmos industrializáveis e da produtividade de colmos). Para esse estudo, instalou-se um experimento em campo, na Fazenda Experimental Santa Terezinha, município de Jaboticabal (SP), em soqueira de cana-de-açúcar cultivar SP 79-1011, em Latossolo Vermelho distrófico, com as doses de nitrogênio: zero; 50; 100 ; 150 e 200 kg ha-1 de N. Os tratamentos foram aplicados após o corte da cana-planta em junho/2005. Foram avaliados durante os dois primeiros cortes da soqueira de cana-de-açúcar a fertilidade do solo (camadas 0-20 e 20-40 cm), o estado nutricional, o desenvolvimento e a produtividade de colmos. A adubação nitrogenada em soqueira de cana-de-açúcar promoveu acidificação do solo restrita à camada superficial (0-20 cm); entretanto, não aumentou significativamente os teores de macro e micronutrientes nas folhas, exceto o N na segunda soqueira. A resposta das duas primeiras soqueiras de cana-de-açúcar à aplicação de nitrogênio, em sistema de colheita sem queima, ocorreu apenas no segundo corte. A dose de 200 kg ha-1 de N promoveu aumento no desenvolvimento da cultura, na nutrição da planta e na produtividade de colmos da soqueira da cana-de-açúcar.
Revisão de Pseudoparlatoria (Hemiptera, Diaspididae)
Authors: Wolff Vera Regina dos S.
Published: January 2009

Revisou-se a taxonomia das espécies incluídas em Pseudoparlatoria Cockerell, 1892, através do exame das séries tipo, exemplares obtidos nas localidades-tipo e material disponível em coleções científicas. Foram redescritas: P. argentata Hempel, 1912; P. browni McKenzie, 1963; P. campinensis Lepage & Giannotti, 1946; P. carolilehmanni Balachowsky, 1959; P. caucae Balachowsky, 1959; P. circularis Lepage, 1942; P. constricta Fonseca, 1975; P. elongata Ferris, 1941; P. fuscaFerris, 1941; P. fusiformisFonseca, 1969; P. lentigo Ferris, 1942; P. maculata Ferris, 1942; P. noacki Cockerell, 1898; P. occultata (Hempel, 1937); P. ostreataCockerell, 1892; P. parlatorioides(Comstock, 1883); P. perparvula Ferris, 1942; P. pisai (Hempel, 1904); P. punctata Ferris, 1942; P. rossetae Fonseca, 1969; P. serrulata Townsend & Cockerell, 1898; P. subcircularis Balachowsky, 1959; P. tillandsiae Tippins, 1970; P. trimaculata Lepage & Giannotti, 1946; P. turgida Ferris, 1941. Duas novas combinações são estabelecidas, P. mammata(Ferris, 1941); P. sculpta (Ferris, 1941). Uma chave para identificação das espécies é apresentada.