bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbon fibre-reinforced plastic truss structures for satellite using braiding/resin transfer moulding process
Authors: Uozumi T , Kito A
Published: May 2007

Surveillance satellites require dimensional stability against temperature variation since the performance of precision optical devices depends on dimensional stability. Dimensional stability can be improved by decreasing the linear thermal expansion of truss structural parts. In this study, a whole truss structure was produced, consisting of several structural units including joints made by using a braiding/resin transfer moulding (RTM) process. Our braiding technologies with a robotic mechanism are capable of braiding not only straight tubes but also divaricate configurations such as of tri-axial truss joints. Braided carbon fibre preforms were moulded using an RTM process with polycyanate resin in order to investigate the mechanical properties and coefficient of linear thermal expansion. Braided carbon fibre-reinforced plastic (CFRP) truss joints and truss structures were produced as examples of aerospace applications by using the braiding/RTM process, in order to evaluate their mechanical properties and carry out structural testing. The modulus and stiffness of braided CFRP truss joints and truss structures were evaluated by comparison with aluminium (Al) and titanium (Ti) alloys. It was clarified that CFRP truss joints have superior specific mechanical and thermal properties as compared to the conventional materials such as Al and Ti alloys. The CFRP truss joint makes the truss structure construction lighter.
Perspective: Quantifying Osteoblast and Osteocyte Apoptosis: Challenges and Rewards
Authors: Jilka Robert L , Weinstein Robert S , Parfitt A Michael , Manolagas Stavros C
Published: June 2007

Since the initial demonstration of the phenomenon in murine and human bone sections ∼10 yr ago, appreciation of the biologic significance of osteoblast apoptosis has contributed greatly not only to understanding the regulation of osteoblast number during physiologic bone remodeling, but also the pathogenesis of metabolic bone diseases and the pharmacology of some of the drugs used for their treatment. It is now appreciated that all major regulators of bone metabolism including bone morphogenetic proteins (BMPs), Wnts, other growth factors and cytokines, integrins, estrogens, androgens, glucocorticoids, PTH and PTH-related protein (PTHrP), immobilization, and the oxidative stress associated with aging contribute to the regulation of osteoblast and osteocyte life span by modulating apoptosis. Moreover, osteocyte apoptosis has emerged as an important regulator of remodeling on the bone surface and a critical determinant of bone strength, independently of bone mass. The detection of apoptotic osteoblasts in bone sections remains challenging because apoptosis represents only a tiny fraction of the life span of osteoblasts, not unlike a 6-mo -long terminal illness in the life of a 75-yr -old human. Importantly, the phenomenon is 50 times less common in human bone biopsies because human osteoblasts live longer and are fewer in number. Be that as it may, well-controlled assays of apoptosis can yield accurate and reproducible estimates of the prevalence of the event, particularly in rodents where there is an abundance of osteoblasts for inspection. In this perspective, we focus on the biological significance of the phenomenon for understanding basic bone biology and the pathogenesis and treatment of metabolic bone diseases and discuss limitations of existing techniques for quantifying osteoblast apoptosis in human biopsies and their methodologic pitfalls.
Pregnancy and STD Prevention Counseling Using an Adaptation of Motivational Interviewing: A Randomized Controlled Trial
Authors: Petersen Ruth , Albright Jennifer , Garrett Joanne M. , Curtis Kathryn M.
Published: June 2007

CONTEXT:  Given levels of unintended pregnancy and STDs, an effective counseling intervention is needed to improve women’s consistent use of effective prevention methods.

METHODS:  A sample of 764 women aged 16–44 who were at risk of unintended pregnancy were enrolled in a randomized controlled trial in North Carolina in 2003–2004. Intervention participants received pregnancy and STD prevention counseling, adapted from motivational interviewing, both at enrollment and two months later; controls received only a session of general health counseling. Levels of contraceptive use (categorized as high, low or none on the basis of the effectiveness of the method and the consistency of use) and barriers to use were measured at two, eight and 12 months; chi‐square tests were used to compare selected outcomes between the groups. Rates of unintended pregnancy and chlamydia infection were assessed over the study period.

RESULTS:  At baseline, 59% of all participants reported a high level of contraceptive use, 19% a low level and 22% nonuse. At two months, the proportions of intervention and control participants who had improved their level of use or maintained a high level (72% and 66%, respectively) were significantly larger than the proportions who had reported a high level of use at baseline (59% and 58%, respectively). No significant differences were found between the groups at 12 months, or between baseline and 12 months for either group. During the study, 10–11% of intervention and control participants became pregnant, 1–2% received a chlamydia diagnosis and 7–9% had another STD diagnosed.

CONCLUSIONS:  Repeated counseling sessions may be needed to improve contraceptive decision‐making and to reduce the risk of unintended pregnancy and STDs.
Social Ecological Predictors of Repeat Adolescent Pregnancy
Authors: Raneri Leslie G. , Wiemann Constance M.
Published: June 2007

CONTEXT: Women with multiple pregnancies in adolescence may experience medical, psychological and social complications. Improved understanding of the individual‐, dyad‐, family‐, peer/community‐ and social system‐level risk factors for repeat pregnancy may lead to the development of more effective prevention strategies for adolescent mothers in a variety of settings.

METHODS: Between 1993 and 1996, white, black and Mexican American adolescent mothers at a labor and delivery unit in Texas were interviewed after delivery and completed written surveys prospectively for up to 48 months. Logistic regression analyses were used to determine predictors of repeat pregnancy within 24 months, using social ecological theory as a guide.

RESULTS: Forty‐two percent of adolescent mothers experienced a repeat pregnancy within 24 months; 73% of these delivered a second child. Individual‐level predictors were planning to have another baby within five years (odds ratio, 1.6) and not using long‐acting contraceptives within three months of delivery (2.4). Dyad‐level predictors were not being in a relationship with the father of the first child three months after delivery (2.0), being more than three years younger than the first child’s father (1.6) and experiencing intimate partner violence within three months after delivery (1.9). Peer/community‐level predictors were not being in school three months postpartum (1.8) and having many friends who were adolescent parents (1.5).

CONCLUSION: Adolescent mothers are at high risk for a rapid subsequent pregnancy. Interventions that address the complex and multifaceted aspects of the lives of adolescent mothers are needed to prevent repeat pregnancy.
Building Bridges, Not Barriers: Inviting Chuukese Family Involvement in Hawaii Schools
Authors: Iding Marie , Cholymay Novia , Kaneshiro Sandra
Published: June 2007

Chuukese students and parents in Hawaii were interviewed about differences between schools in Hawaii and Chuuk, aspects of schooling in Hawaii that affected adjustment and suggestions for increasing Chuukese family involvement. Differences between schools in Hawaii and Chuuk included availability of materials, different expectations for teachers and students, lack of English language instruction in Chuuk and variable reading background or preparation. Barriers to adjustment to Hawaii schools included limited English proficiency, peer pressure, teachers' negative expectations or prejudice about Micronesian students and ethnic conflicts. Suggestions to facilitate family involvement and make schools more inviting included providing sports clubs for Micronesian students, opportunities for Micronesian students to share about their culture with other students and providing translators at parent–teacher meetings.
A Snapshot of Five Materialism Studies in Australia
Authors: Saunders Shaun A.
Published: June 2007

Our consumer-driven society is dependent upon economic growth and people's belief that acquiring possessions will make them happier. However, the present results suggest that materialistic values and behaviours might not be associated with psychological health or individual life satisfaction in Australia. This might be attributed in part to materialism being based largely on the process of social comparison. Furthermore, materialistic values and behaviours also do not appear to be congruent with either a love of life itself — biophilia — or environmental concerns. If materialistic persons are indeed more dependent on comparisons with others, then it might be reasonably hypothesised that they would also score lower on self-esteem, and this should be a direction for future research.
Firearm Ownership and Storage Patterns Among Families With Children Who Receive Well-Child Care in Pediatric Offices
Authors: DuRant Robert H. , Barkin Shari , Craig Joseph A. , Weiley Victoria A. , Ip Edward H. , Wasserman Richard C.
Published: June 2007

OBJECTIVE. In this study we examined firearm storage patterns and their associations in a diverse sample of families who attended pediatric practices from both rural and nonrural areas across the United States.

METHODS. Parents who brought their children who were aged 2 to 11 years (N = 3745) to 96 Pediatric Research in Office Settings practices from 45 states, Canada, and Puerto Rico participated in an office-based survey before a well-child examination. The survey measured demographic variables; family history of guns in the home; and firearm types, storage behaviors, and ownership.

RESULTS. Twenty-three percent of families reported firearm ownership. The majority (60%) of respondents reported making firearm storage decisions. Only one third of firearm owners reported safe firearm storage. Gun type owned was associated with storage habits, with long-gun owners storing their gun in places other than locked cabinets but with ammunition separate from guns and handgun users more likely to store guns loaded and to use gun locks. In a multivariate analysis, not being raised with a firearm was associated with safe storage behaviors. Families who had children aged 2 to 5 years and owned long guns were more likely to store their guns safely than families with older children.

CONCLUSIONS. Few families reported safe firearm storage. Storage patterns are most influenced by firearm type(s) owned, family socialization with guns, and the age of the child. Primary care providers need to understand better not only whether firearms are in the home but also which types are present and whether parents were raised in homes with guns.
The Role of Mometasone Furoate Aqueous Nasal Spray in the Treatment of Adenoidal Hypertrophy in the Pediatric Age Group: Preliminary Results of a Prospective, Randomized Study
Authors: Berlucchi Marco , Salsi Daria , Valetti Luisa , Parrinello Giovanni , Nicolai Piero
Published: May 2007

OBJECTIVE. We evaluated the efficacy of mometasone furoate aqueous nasal spray in decreasing adenoid size and reducing the severity of chronic nasal obstruction symptoms in children affected by adenoidal hypertrophy.

METHODS. Sixty children were recruited in a 2-stage, randomized, placebo-controlled trial. All patients complained of chronic nasal obstruction symptoms, and nasal endoscopy showed >75% choanal obstruction attributable to adenoid pads. In the first stage, 30 patients (group A) underwent mometasone treatment (50 μg per nostril per day) for 40 days, and 30 children (group B) received placebo. In the second stage, at the end of the first 40-day treatment period, patients in group A who showed subjective and objective clinical improvement were divided into 2 subgroups; group A1 (11 children) received topical intranasal steroid treatment on alternate days for the first 2 weeks per month, whereas group A2 (10 children) continued daily mometasone treatment for the first 2 weeks per month. After 3 months, all children were reassessed.

RESULTS. Fifty-seven children completed the study according to the protocol. After the first treatment period, the severity of symptoms and adenoid size decreased for 21 patients (77.7%) in group A. No improvement was observed in the placebo group. After 3 months of additional therapy, group A2 patients demonstrated a more-pronounced reduction in adenoid size compared with group A1 patients. No statistically significant change in symptoms was identified. Mometasone treatment was well tolerated by all patients.

CONCLUSIONS. Mometasone furoate aqueous nasal spray may be considered useful in decreasing adenoid pad size and the severity of symptoms related to adenoidal hypertrophy. Children with adenoidal hypertrophy that is not associated with tonsillar hypertrophy should be considered for intranasal mometasone treatment before surgery is planned.
Intensive Home Visiting Is Associated With Decreased Risk of Infant Death
Authors: Donovan Edward F. , Ammerman Robert T. , Besl John , Atherton Harry , Khoury Jane C. , Altaye Mekibib , Putnam Frank W. , Van Ginkel Judith B.
Published: June 2007

OBJECTIVE. The goal was to test the hypothesis that participation in a community-based home-visiting program is associated with a decreased risk of infant death.

METHODS. A retrospective, case-control design was used to compare the risk of infant death among participants in Cincinnati's Every Child Succeeds program and control subjects matched for gestational age at birth, previous pregnancy loss, marital status, and maternal age. The likelihood of infant death, adjusted for level of prenatal care, maternal smoking, maternal education, race, and age, was determined with multivariate logistic regression. The interaction between race and program participation and the effect of home visiting on the risk of preterm birth were explored.

RESULTS. Infants whose families did not receive home visiting (n = 4995) were 2.5 times more likely to die in infancy compared with infants whose families received home visiting (n = 1665). Black infants were at least as likely to benefit from home visiting as were nonblack infants. No effect of program participation on the risk of preterm birth was observed.

CONCLUSION. The current study is consistent with the hypothesis that intensive home visiting reduces the risk of infant death.
Do Skinfold Measurements Provide Additional Information to Body Mass Index in the Assessment of Body Fatness Among Children and Adolescents?
Authors: Mei Zuguo , Grummer-Strawn Laurence M. , Wang Jack , Thornton John C. , Freedman David S. , Pierson Richard N. , Dietz William H. , Horlick Mary
Published: June 2007

OBJECTIVES. The purpose of this work was to validate the performance of age- and gender-specific BMI, triceps, and subscapular skinfold for the classification of excess of body fat in children and adolescents and to examine how much additional information these 2 skinfold measurements provide to BMI-for-age.

METHODS. The receiver operating characteristic curve was used to characterize the sensitivity and specificity of these 3 indices in classifying excess body fat. Percentage of body fat was determined by dual-energy radiograph absorptiometry. Both ≥85th and ≥95th percentile of percentage of body fat were used to define excess body fat. Data from the New York Pediatric Rosetta Body Composition Project were examined (n = 1196; aged 5–18 years).

RESULTS. For children aged 5 to 18 years, BMI-for-age, triceps skinfold-for-age, and subscapular skinfold-for-age each performed equally well alone in the receiver operating characteristic curves in the identification of excess body fat defined by either the 85th or 95th percentile of percentage of body fat by dual-energy radiograph absorptiometry. However, if BMI-for-age was already known and was >95th percentile, the additional measurement of skinfolds did not significantly increase the sensitivity or specificity in the identification of excess body fat.

CONCLUSIONS. In contrast to the recommendations of expert panels, skinfold measurements do not seem to provide additional information about excess body fat beyond BMI-for-age alone if the BMI-for-age is >95th percentile.
Between Stillness and Story: Lessons of Children's Illness Narratives
Authors: DasGupta Sayantani
Published: June 2007

In answer to an increasingly impersonal medical environment, educators in the medical humanities frequently turn to narrative studies to teach students for an emotionally fulfilling and interpersonally related professional practice. However, to elicit, to interpret, and to integrate patient stories into their work effectively, physicians must be in a state of awareness and attention, attuned to their emotional and intellectual reactions. The experiences of children and their families, in the form of pediatric illness narratives, hold unique insights for physicians in how to engage in an ethical, empathetic, and self-reflective practice. In particular, these narratives demonstrate the importance not only of story but also of stillness or silence to the practice of medicine. The voices of patients and their families hold both literal and allegorical lessons for physicians in how to move toward a medical practice involving not only diagnosis and treatment but also recognition and healing.
Maternal Asthma and Maternal Smoking Are Associated With Increased Risk of Bronchiolitis During Infancy
Authors: Carroll Kecia N. , Gebretsadik Tebeb , Griffin Marie R. , Dupont William D. , Mitchel Edward F. , Wu Pingsheng , Enriquez Rachel , Hartert Tina V.
Published: June 2007

OBJECTIVE. Our goal was to determine whether maternal asthma and maternal smoking during pregnancy are associated with the incidence and severity of clinically significant bronchiolitis in term, otherwise healthy infants without the confounding factors of small lung size or underlying cardiac or pulmonary disease.

PATIENTS AND METHODS. We conducted a population-based retrospective cohort study of term, non–low birth weight infants enrolled in the Tennessee Medicaid Program from 1995 to 2003. The cohort of infants was followed through the first year of life to determine the incidence and severity of bronchiolitis as determined by health care visits and prolonged hospitalization.

RESULTS. A total of 101245 infants were included. Overall, 20% of infants had ≥1 health care visit for bronchiolitis. Compared with infants with neither factor, the risk of bronchiolitis was increased in infants with maternal smoking only, maternal asthma only, or both. Infants with maternal asthma only or with both maternal smoking and asthma had the highest risks for emergency department visits and hospitalizations. Infants with a mother with asthma had the highest risk of a hospitalization >3 days, followed by infants with both maternal asthma and smoking, and maternal smoking only.

CONCLUSIONS. Maternal asthma and maternal smoking during pregnancy are independently associated with the development of bronchiolitis in term, non–low birth weight infants without preexisting cardiac or pulmonary disease. The risk of bronchiolitis among infants with mothers who both have asthma and smoke during pregnancy is ∼50% greater than that of infants with neither risk factor. Efforts to decrease the illness associated with these 2 risk factors will lead to decreased morbidity from bronchiolitis, the leading cause of hospitalization for severe lower respiratory tract infections during infancy.
Incidence of Acute Otitis Media and Sinusitis Complicating Upper Respiratory Tract Infection: The Effect of Age
Authors: Revai Krystal , Dobbs Laura A. , Nair Sangeeta , Patel Janak A. , Grady James J. , Chonmaitree Tasnee
Published: June 2007

Infants and young children are prone to developing upper respiratory tract infections, which often result in bacterial complications such as acute otitis media and sinusitis. We evaluated 623 upper respiratory tract infection episodes in 112 children (6–35 months of age) to determine the proportion of upper respiratory tract infection episodes that result in acute otitis media or sinusitis. Of all upper respiratory tract infections, 30% were complicated by acute otitis media and 8% were complicated by sinusitis. The rate of acute otitis media after upper respiratory tract infection declined with increasing age, whereas the rate of sinusitis after upper respiratory tract infection peaked in the second year of life. Risk for acute otitis media may be reduced substantially by avoiding frequent exposure to respiratory viruses (eg, avoidance of day care attendance) in the first year of life.
Temporal Relationships Between Colds, Upper Respiratory Viruses Detected by Polymerase Chain Reaction, and Otitis Media in Young Children Followed Through a Typical Cold Season
Authors: Winther Birgit , Alper Cuneyt M. , Mandel Ellen M. , Doyle William J. , Hendley J. Owen
Published: June 2007

INTRODUCTION. Otitis media is a frequent complication of a viral upper respiratory tract infection, and the reported co-incidence of those diseases increases with assay sensitivity and sampling density. We determined the incidence of otitis-media complications in young children when referenced to cold-like illnesses and to concurrent virus recovery from the nasopharynx.

METHODS. A total of 60 children from 24 families were followed from October 2003 through April 30, 2004, by daily parental recording of illness signs, weekly pneumatic otoscopic examinations, and periodic polymerase chain reaction assay of collected nasal fluids for common viruses.

RESULTS. One hundred ninety-nine cold-like illnesses were observed, but a sample for virus assay was not collected concurrent with 71 episodes. Of the remainder, 73% of cold-like illnesses were temporally related to recovery of 1 or a combination of the assayed viruses, with rhinovirus predominating. For non–cold-like illness periods, 54 (18%) of 297 assays were positive for virus, and the virus frequency distribution was similar to that for cold-like illnesses. There were 93 diagnosed otitis-media episodes; 65 (70%) of these occurred during a cold-like illness. For the 79 otitis-media episodes with available nasal samples, 61 (77%) were associated with a positive virus result. In this population, the otitis-media complication rate for a cold-like illness was 33%.

CONCLUSIONS. A cold-like illness was not a prerequisite for polymerase chain reaction detection of viruses in the nose and nasopharynx of young children. Viral detection by polymerase chain reaction in the absence of a cold-like illness is associated with complications in some subjects. Otitis media is a complication of viral infection both with and without concurrent cold-like illnesses, thus downwardly biasing coincidence estimates that use cold-based illnesses as the denominator.
A National Outbreak of Ralstonia mannitolilytica Associated With Use of a Contaminated Oxygen-Delivery Device Among Pediatric Patients
Authors: Jhung Michael A. , Sunenshine Rebecca H. , Noble-Wang Judith , Coffin Susan E. , St John Keith , Lewis Felicia M. , Jensen Bette , Peterson Alicia , LiPuma John , Arduino Matthew J. , Holzmann-Pazgal Galit , Atkins Jane T. , Srinivasan Arjun
Published: June 2007

OBJECTIVES. In August 2005, the Centers for Disease Control and Prevention was notified of a Ralstonia species outbreak among pediatric patients receiving supplemental oxygen therapy with the Vapotherm 2000i (Vapotherm, Inc, Stevensville, MD). The Vapotherm 2000i is a reusable medical device that was used in >900 hospitals in the United States in 2005. Ralstonia are waterborne bacilli that have been implicated in hospital-acquired infections. We initiated an investigation to determine the source of the outbreak and implement infection control and prevention measures.

PATIENTS AND METHODS. We performed a case-control study at 1 hospital and conducted national case findings to obtain clinical and environmental samples for laboratory analysis. Case-patients had health care–acquired Ralstonia colonization or infection. Isolates were compared by using pulsed-field gel electrophoresis. We tested manufacturer-recommended disinfection protocols for the Vapotherm 2000i under simulated-use conditions.

RESULTS. Case-patients at the hospital (n = 5) were more likely to have received Vapotherm therapy than controls. Nationally, Ralstonia mannitolilytica was confirmed in 38 patients (aged 5 days to 7 years); 35 (92%) of the patients were exposed to the Vapotherm 2000i before recovery of the organism. Pulsed-field gel electrophoresis showed related R mannitolilytica strains from isolates sent from 18 hospitals in 12 states. A Vapotherm machine reprocessed with a protocol proposed by the manufacturer grew Ralstonia spp after 7 days of simulated use. In December 2005, Vapotherm recalled the 2000i.

CONCLUSIONS. Our findings suggest intrinsic contamination of Vapotherm devices with Ralstonia spp. New medical devices may provide therapy equivalent to current devices yet pose novel reprocessing challenges.
Overuse Injuries, Overtraining, and Burnout in Child and Adolescent Athletes
Authors: Brenner Joel S. ,   and the Council on Sports Medicine and Fitness
Published: June 2007

This Clinical Report was revised. See https://doi.org/10.1542/peds.2023-065129.

Overuse is one of the most common etiologic factors that lead to injuries in the pediatric and adolescent athlete. As more children are becoming involved in organized and recreational athletics, the incidence of overuse injuries is increasing. Many children are participating in sports year-round and sometimes on multiple teams simultaneously. This overtraining can lead to burnout, which may have a detrimental effect on the child participating in sports as a lifelong healthy activity. One contributing factor to overtraining may be parental pressure to compete and succeed. The purpose of this clinical report is to assist pediatricians in identifying and counseling at-risk children and their families. This report supports the American Academy of Pediatrics policy statement on intensive training and sport specialization.
Densification and microstructure development in spark plasma sintered WC–6 wt% ZrO2 nanocomposites
Authors: Biswas Krishanu , Mukhopadhyay Amartya , Basu Bikramjit , Chattopadhyay Kamanio
Published: June 2007

In this paper, we report the results of a transmission electron microscopy investigation on WC–6 wt% ZrO2nanocomposite, spark plasma sintered at 1300 °C, for varying times of up to 20 min. The primary aim of this work was to understand the evolution of microstructure during such a sintering process. The investigation revealed the presence of nanocrystalline ZrO2particles (30–50 nm) entrapped within submicron WC grains. In addition, relatively coarser ZrO2(60–100 nm) particles were observed to be either attached to WC grain boundaries or located at WC triple grain junctions. The evidence of the presence of a small amount of W2C, supposed to have been formed due to sintering reaction between WC and ZrO2, is presented here. Detailed structural investigation indicated that ZrO2in the spark plasma sintered nanocomposite adopted an orthorhombic crystal structure, and the possible reasons for o-ZrO2formation are explained. The increase in kinetics of densification due to the addition of ZrO2is believed to be caused by the enhanced diffusion kinetics in the presence of nonstoichiometric nanocrystalline ZrO2.
Titania nanotubes prepared by anodization in fluorine-free acids
Authors: Richter C. , Panaitescu E. , Willey R. , Menon L.
Published: June 2007

Recently, we reported the discovery of new high-aspect ratio titania nanotubes. These nanotubes were synthesized by means of anodization in an oxalic acid electrolyte containing chlorine ions and were found to have significant carbon content. In this article, the synthesis of similar titania nanotubes in oxalic, formic, trichloroacetic, gluconic, hydrochloric, and sulfuric acid is reported. Differences in carbon content and morphology are analyzed, which in turn provides information on the chemistry of the formation of these nanotubes. Our results suggest that the carbon content in the nanotubes can be controlled by the use of an appropriate organic acid.
Assessment of geometrical and transport properties of a fibrous C/C composite preform as digitized by x-ray computerized microtomography: Part II. Heat and gas transport properties
Authors: Vignoles Gerard L. , Coindreau Olivia , Ahmadi Azita , Bernard Dominique
Published: June 2007

Raw and partially infiltrated carbon–carbon composite preforms have been scanned by high-resolution synchrotron radiation x-ray computerized microtomography. Three-dimensional high-quality images of the pore space have been produced at two distinct resolutions and have been used for the computation of transport properties: heat conductivity, binary gas diffusivities, Knudsen diffusivities, and viscous flow permeabilities. The computation procedures are based on a double change-of-scale strategy suited to the bimodal nature of pore space and on the local determination of transport anisotropy. Good agreement has been found between all calculated quantities and experimental data.
Tissue Engineering with Chondrogenically Differentiated Human Embryonic Stem Cells
Authors: Koay Eugene J. , Hoben Gwen M. B. , Athanasiou Kyriacos A.
Published: June 2007

This study describes the development and application of a novel strategy to tissue engineer musculoskeletal cartilages with human embryonic stem cells (hESCs). This work expands the presently limited understanding of how to chondrogenically differentiate hESCs through the use of chondrogenic medium alone (CM) or CM with two growth factor regimens: transforming growth factor (TGF)-β3 followed by TGF-β1 plus insulin-like growth factor (IGF)-I or TGF-β3 followed by bone morphogenic protein (BMP)-2. It also extends the use of the resulting chondrogenically differentiated cells for cartilage tissue engineering through a scaffoldless approach called self-assembly, which was conducted in two modes: with (a) embryoid bodies (EBs) or (b) a suspension of cells enzymatically dissociated from the EBs. Cells from two of the differentiation conditions (CM alone and TGF-β3 followed by BMP-2) produced fibrocartilage-like constructs with high collagen I content, low collagen II content, relatively high total collagen content (up to 24% by dry weight), low sulfated glycosaminoglycan content (∼4% by dry weight), and tensile properties on the order of megapascals. In contrast, hESCs treated with TGF-β3 followed by TGF-β1 + IGF-I produced constructs with no collagen I. Results demonstrated significant differences among the differentiation conditions in terms of other biochemical and biomechanical properties of the self-assembled constructs, suggesting that distinct growth factor regimens differentially modulate the potential of the cells to produce cartilage. Furthermore, this work shows that self-assembly of cells obtained by enzymatic dissociation of EBs is superior to self-assembly of EBs. Overall, the results of this study raise the possibility of manipulating the characteristics of hESC-generated tissue toward specific musculoskeletal cartilage applications.

Disclosure of potential conflicts of interest is found at the end of this article.
Functional characterization of human 1-acylglycerol-3-phosphate-O-acyltransferase isoform 9: cloning, tissue distribution, gene structure, and enzymatic activity
Authors: Agarwal Anil K , Sukumaran Suja , Bartz Rene , Barnes Robert I , Garg Abhimanyu
Published: May 2007

Most cells synthesize their glycerophospholipids and triglycerides (TG) to maintain the cellular integrity and to provide energy for cellular functions. The phospholipids are synthesized de novo in cells through an evolutionary conserved process involving serial acylations of glycerol-3-phosphate. Several isoforms of the enzyme 1-acylglycerol-3-phosphate-O-acyltransferase (AGPAT) acylate lysophosphatidic acid at the sn-2 position to produce phosphatidic acid. We cloned a cDNA predicted to be an AGPAT isoform and designated it AGPAT9. The human AGPAT9 gene spans across 14 exons and encodes for a polypeptide of 534 amino acids. AGPAT9 is highly expressed in the lung and spleen, followed by leukocyte, omental adipose tissue, and placenta. In the Chinese Hamster Ovary (CHO), cell lysates overexpressing AGPAT9, we observed AGPAT activity but not the lysophosphatidylcholine acyltransferase activity. When AGPAT9 is coexpressed with AGPAT1 in CHO cells, both the isoforms localize to the endoplasmic reticulum (ER) and occupy the same ER domain as AGPAT1. Despite substitution of asparagine with proline in the NHX4D motif and arginine with cysteine in the EGTR motif, AGPAT9 retains AGPAT activity suggesting that residues asparagine and arginine in the NHX4D and EGTR motifs respectively are not essential for the enzymatic activity. Based on the X-ray crystallographic structure of a related acyltransferase, squash gpat, a model is proposed in which a hydrophobic pocket in AGPAT9 accommodates fatty acyl chains of both substrates in an orientation, whereas the HX4D motif participates in catalysis. Based on the activity and expression pattern of AGPAT9 in the lung and spleen, this novel isoform could be implicated in the biosynthesis of phospholipids and TG in these tissues.
Regulation of glucokinase in pancreatic islets by prolactin: a mechanism for increasing glucose-stimulated insulin secretion during pregnancy
Authors: Weinhaus Anthony J , Stout Laurence E , Bhagroo Nicholas V , Brelje T Clark , Sorenson Robert L
Published: May 2007

Glucokinase activity is increased in pancreatic islets during pregnancy and in vitro by prolactin (PRL). The underlying mechanisms that lead to increased glucokinase have not been resolved. Since glucose itself regulates glucokinase activity in β-cells, it was unclear whether the lactogen effects are direct or occur through changes in glucose metabolism. To clarify the roles of glucose metabolism in this process, we examined the interactions between glucose and PRL on glucose metabolism, insulin secretion, and glucokinase expression in insulin 1 (INS-1) cells and rat islets. Although the PRL-induced changes were more pronounced after culture at higher glucose concentrations, an increase in glucose metabolism, insulin secretion, and glucokinase expression occurred even in the absence of glucose. The presence of comparable levels of insulin secretion at similar rates of glucose metabolism from both control and PRL-treated INS-1 cells suggests the PRL-induced increase in glucose metabolism is responsible for the increase in insulin secretion. Similarly, increases in other known PRL responsive genes (e.g. the PRL receptor, glucose transporter-2, and insulin) were also detected after culture without glucose. We show that the upstream glucokinase promoter contains multiple STAT5 binding sequences with increased binding in response to PRL. Corresponding increases in glucokinase mRNA and protein synthesis were also detected. This suggests the PRL-induced increase in glucokinase mRNA and its translation are sufficient to account for the elevated glucokinase activity in β-cells with lactogens. Importantly, the increase in islet glucokinase observed with PRL is in line with that observed in islets during pregnancy.
Effects of maternal nuclear genome on the timing of puberty in mice offspring
Authors: Zhou Yuxun , Zhu Wangsheng , Guo Zhengxia , Zhao Ying , Song Zijun , Xiao Junhua
Published: May 2007

The timing of puberty is a complex trait which is regulated by environmental and genetic factors, but the detailed regulatory mechanism remains elusive. Maternal nutrition administration during late gestation in rats revealed that the time of onset of puberty in daughter rats was influenced by the mother’s nutritional and physiological status during the embryonic development period. In this study, the potential effects of the maternal nuclear genome on the timing of puberty of offspring were investigated. Two inbred strains of mice (C3H/HeJ (C3H) and C57BL/6J (B6)) were used to set up two pedigrees (direct and reciprocal crosses), and the timing of puberty in all these mice (parent, F1 and F2) was recorded (the females were assessed by vaginal opening (VO) and the males by balano preputial separation (BPS)). The results from data of 822 mice showed that: 1) in female mice, the heritability of the timing of puberty in direct and reciprocal crosses is 68.51% and 63.97% respectively; 2) in female mice, a significant difference in the timing of puberty is observed between B6 and C3H (P = 3.7 × 10−13) mice as well as between direct and reciprocal F1 hybrids (P = 5.4 × 10−3), but not between direct and reciprocal F2 hybrids (P = 0.0941); 3) in male mice, direct and reciprocal F1 hybrids differ significantly from each other in the timing of BPS (P = 2.7 × 10−7), while such differences vanish in their male progenitor and progeny. The significant discrepancy between direct and reciprocal crosses in F1 but not in either cross of F2 hybrids reveals that the maternal nuclear genome has effects on the timing of puberty in mice progeny, probably through imprinting genes or the genes associated with intra-uterine physiological status.
Reconstruction of Bryn-y-Felin Railway Bridge, Snowdonia
Authors: Sreeves J. C.
Published: June 2007

A project is under way to reinstate the narrow gauge Welsh Highland Railway between Caernarfon and Porthmadog in North Wales. Progress to date has seen the railway opened for 19·4 km between Caernarfon and Rhyd Ddu. The remaining 20·3 km section between Rhyd Ddu and Porthmadog is due for completion in 2009, which when connected with the existing Ffestiniog Railway at Porthmadog will result in the longest heritage railway in Britain by far, with a total length of nearly 62 km. Bryn-y-Felin Bridge forms a prominent landmark where the railway crosses over the Glaslyn River near Beddgelert in the heart of the Snowdonia National Park, near to the popular and much photographed beauty spot of the Aberglaslyn Pass. The structural form of the bridge is a steel half-through Warren truss, replicating the style of the previous bridge on the site. The aim was to produce a cost-effective design that reflected the heritage of the railway, and that could be readily constructed and maintained.
Jamestown Viaduct, UK: strengthening of an early steel viaduct
Authors: Roberts C. , Hanson A. , Henderson D. , Bell G.
Published: June 2007

Jamestown Viaduct is a six-span railway viaduct constructed between 1887 and 1890 in Scotland, UK. The four main spans are of early steel construction, supported by masonry piers and abutments. Each of the steel spans comprises two simply supported main truss girders with cross-girders supported on the top chords at truss nodes with rail bearers and steel deck plates supporting ballasted track. The structure is Grade B listed. Previous structural assessments had shown that the viaduct did not meet Network Rail's requirements in terms of live load-carrying capacity. A design competition was used by Network Rail and Mowlem (now part of Carillion plc) to choose an outline design for strengthening. This paper describes the unique solution proposed and developed by Corus to take advantage of an eight-day possession for maintenance work on the nearby Forth Bridge. The work involved removal of the track and construction of an in situ reinforced concrete slab at deck level designed to act compositely with the existing truss girder top chords and cross-girders.
Deflectometer-based analysis of ballasted railway tracks
Authors: Burrow M. P. N. , Chan A. H. C. , Shein A.
Published: May 2007

The falling weight deflectometer (FWD) device is used in the UK for the dynamic testing of ballasted railway track. Using the deflection data obtained from the test, elastic modulus values of the track substructure required to build a numerical model of the track can be determined using a procedure known as back-analysis. The numerical model so calibrated can be used to determine the effect of the traffic loads on the stresses, strains and deformations in the railway track system, and is an important component of an analytical approach to track substructure design. In this paper, the use of dynamic finite-element analysis to back-analyse the material properties of the railway substructure from FWD deflection data has been demonstrated by means of an example. The numerical approach presented is the rational method for FWD-based inverse analysis and condition evaluation of ballasted railway tracks, and becomes practicable owing to continued advances in finite-element and computer technologies.
Parental Grief in Three Societies: Networks and Religion as Social Supports in Mourning
Authors: Hass Jeffrey K. , Walter Tony
Published: May 2007

How do people respond to the grief of parents over the death of their infant child? This article documents the experience of one of the authors, an American married to a Russian whose child died in England. Responses to this death by friends, colleagues and family in the USA, England, and two cities in Russia varied considerably in terms of depth and degree of engagement (emotional engagement, respect, or distance and avoidance). What factors underlie these varied responses? Two are identified, one structural, the other cultural: the strength of the social ties within social networks, and religiosity as historically sedimented within a culture. The degree of engagement is correlated with network form; but the content of engagement depends on religiosity.
Effects of Timber Management on Pond‐Breeding Salamanders
Authors: MORRIS KATRINA M. , MARET TIMOTHY J.
Published: June 2007

Abstract: Pond‐breeding salamanders spend most of their lives in forested habitat surrounding the vernal pools where they breed. Timber harvesting has been demonstrated to have negative impacts on salamander populations due to changes in soil temperature, soil compaction, and general degradation of habitat. However, little is known about how long it takes for harvested forest habitat to once again become suitable for salamanders. Questions also remain as to whether salamanders will use an area that has been harvested in recent years if an older intact forest area is available. We used drift fences and pitfall traps to capture adult spotted salamanders (Ambystoma maculatum) and marbled salamanders (A. opacum) migrating to 3 vernal ponds during their breeding seasons. The study area contained tracts of forest that were clear‐cut 11–12 years prior to the study. All 3 ponds were surrounded by areas of clear‐cut and intact forest and drift fences were placed in both habitat types. Similar numbers of spotted salamanders entered the ponds from clear‐cut and intact forest areas. The number of marbled salamanders migrating to the ponds did not differ between areas of clear‐cut and intact forest. These results suggest that clear‐cut habitats may become suitable for adult pond‐breeding salamanders after a relatively short regeneration period.
Estimates of Survival from Radiotelemetry: a Response to Guthery and Lusk
Authors: FOLK TRAVIS H. , GRAND JAMES B. , PALMER WILLIAM E. , CARROLL JOHN P. , SISSON D. CLAY , TERHUNE THERON M. , WELLENDORF SHANE D. , STRIBLING H. LEE
Published: June 2007

Abstract: Radiotelemetry has become an important and frequently used tool in wildlife research. Inferences drawn from radiotelemetry data depend on the assumption that the radiotransmitters are not influencing parameter(s) of interest. An article by Guthery and Lusk (2004) in the Wildlife Society Bulletin questioned the validity of this assumption for estimating survival rates of northern bobwhites (Colinus virginianus) using radiotelemetry data. In this evaluation, we address technical and philosophical flaws in Guthery and Lusk's (2004) critique of northern bobwhite studies utilizing radiotelemetry. They concluded that biologists should be skeptical of radiotelemetry studies and they advised researchers to design studies to address potential biases caused by radiotransmitters using independent data. Although we agree that researchers are responsible for testing key assumptions of their techniques, we believe Guthery and Lusk's (2004) conclusions were not well supported and were based on tenuous assumptions. Guthery and Lusk (2004) calculated the level of productivity (given as a fall age ratio) required to balance a simple population model that contained published estimates of annual survival and assumed an annual finite population growth rate of 1.0. We review their population model and show that the relationship between an annual survival rate and fall age ratio is nonlinear. This nonlinearity can lead to biased estimates of a fall age ratio, especially at lower values of annual survival. We also question the validity of using fall age ratios as an estimator of productivity. Further, we suggest that this assessment of a radiotransmitter effect from a survival rate itself is not appropriate. This rate can be depressed (or elevated) for a variety of reasons not related to the influence of radiotransmitters. In addition, Guthery and Lusk (2004) assumed that daily survival rates (as calculated from both annual and seasonal published estimates) were constant throughout the year; thus, they scaled daily survival rates from seasonal to annual estimates. Further, their meta‐analysis was hindered by temporal pseudoreplication and a lack of independence among the observations used in the analysis. We conclude the weight of the evidence presented by Guthery and Lusk (2004) is not as strong as they claim because it fails to meet the test of sufficient causation. While scientists should always be skeptical and critical of assumptions of all methods employed in wildlife research, more rigorous tests are necessary before we discredit a valuable technique without sufficient empirical evidence.
Stress Response of Working African Elephants to Transportation and Safari Adventures
Authors: MILLSPAUGH JOSHUA J. , BURKE TARRYNE , VAN DYK GUS , SLOTOW ROB , WASHBURN BRIAN E. , WOODS RAMI J.
Published: June 2007

Abstract:African elephants (Loxodonta africana) are intensively managed in southern Africa and are routinely translocated between reserves. Domesticated elephants are used for elephant‐back safaris and interactions with guests. Understanding how elephants respond to such activities is critical because of welfare issues associated with both humans and elephants. We investigated the stress response (i.e., fecal glucocorticoid metabolite secretion [FGM]) of working elephants in Letsatsing Game Reserve, South Africa, over 1 year to evaluate their response to transportation and ecotourism activities. We used free‐ranging elephants in adjacent Pilanesburg National Park as controls. Fecal glucocorticoid metabolites were greatest prior to and during translocation and declined over the year. Within 1–2 months of transportation, FGM levels in working elephants became indistinguishable from those in wild elephants. Fecal glucocorticoid metabolite levels were higher during human interaction days than days without interaction. The highest observed FGM levels were associated with transportation and episodic loud noises. Transportation is a stressful activity for elephants, and ≥3 months should be provided to translocated elephants to acclimate to their new surroundings. Although stress levels of elephants increased slightly when interacting with humans in the contexts we studied, evaluating interactions under a wider range of contexts is necessary to minimize danger to elephants and humans.