bluuebunny/crossref_metadata_2025 huggingface dataset:
Isoflavones prevent bone loss following ovariectomy in young adult rats
Authors: Tsuang Yang-Hwei , Chen Li-Ting , Chiang Chang-Jung , Wu Lien-Chen , Chiang Yueh-Feng , Chen Pei-Yu , Sun Jui-Sheng , Wang Chien-Che
Published: March 2008

Soy protein, a rich source of phytoestrogens, exhibit estrogen-type bioactivity. The purpose of this study was to determine if ingestion of isoflavones before ovariectomy can prevent bone loss following ovariectomy. Twenty-four nulliparous Wistar rats were randomly divided into four groups. In the normal diet groups, a sham operation was performed on Group A, while ovariectomy was performed on Group B. For Groups C and D, all rats were fed with an isoflavone-rich (25 mg/day) diet for one month, then bilateral ovariectomy were performed. In the rats in Group C, a normal diet was begun following the ovariectomy. The rats in Groups D continued to receive the isoflavone-rich diet for two additional months postoperatively. All rats were sacrificed 60 days after surgery. The weight of bone ash of the long bones and whole lumbar spine were determined. A histological study of cancellous bone was done and biochemical indices of skeletal metabolism were performed and analyzed. The markers of bone metabolism exhibited no significant changes. When compared with the sham-operated rats fed a normal diet, the bone mass of ovariectomized rats decreased significantly; pre-ovariectomy ingestion of an isoflavone-rich diet did not prevent bone loss. The bone mass of rats treated with an isoflavone-rich diet for three months was higher than controls two months after ovariectomy.

Dietary isoflavones did not prevent the development of post-ovariectomy bone loss, but long-term ingestion of an isoflavone-rich diet increased the bone mineral contents after ovariectomy in young rats.
Metabolic profiling reveals therapeutic effects of Herba Cistanches in an animal model of hydrocortisone-induced 'kidney-deficiency syndrome'
Authors: Qiu Yunping , Chen Minjun , Su Mingming , Xie Guoxiang , Li Xin , Zhou Mingmei , Zhao Aihua , Jiang Jian , Jia Wei
Published: March 2008

Background

Herba Cistanches (Roucongrong) is effective in treating Shenxu Zheng ('kidney-deficiency syndrome'). However, the mechanisms and systemic metabolic responses to the herbal intervention are unclear.

Methods

Using GC-MS-based metabolic profiling, we investigated the metabolic responses to Herba Cistanches intervention in a rat model of the hydrocortisone-induced 'kidney-deficiency syndrome'.

Results

The metabolic profiles of the rats after hydrocortisone injection deviated from the pre-dose metabolic state at different time points, ranging from day 1 to day 10, whereas the metabolic profiles of the rats treated with both hydrocortisone and water extract of Herba Cistanches returned to the pre-dose state on day 10.

Conclusion

The intervention of Herba Cistanches caused a systemic recovery from the hydrocortisone-induced metabolic perturbation in rats. This study also demonstrates that metabolic profiling is useful in studying therapeutic mechanisms of herbal medicines.
Evolution of insect proteomes: insights into synapse organization and synaptic vesicle life cycle
Authors: Yanay Chava , Morpurgo Noa , Linial Michal
Published: March 2008

Background

The molecular components in synapses that are essential to the life cycle of synaptic vesicles are well characterized. Nonetheless, many aspects of synaptic processes, in particular how they relate to complex behaviour, remain elusive. The genomes of flies, mosquitoes, the honeybee and the beetle are now fully sequenced and span an evolutionary breadth of about 350 million years; this provides a unique opportunity to conduct a comparative genomics study of the synapse.

Results

We compiled a list of 120 gene prototypes that comprise the core of presynaptic structures in insects. Insects lack several scaffolding proteins in the active zone, such as bassoon and piccollo, and the most abundant protein in the mammalian synaptic vesicle, namely synaptophysin. The pattern of evolution of synaptic protein complexes is analyzed. According to this analysis, the components of presynaptic complexes as well as proteins that take part in organelle biogenesis are tightly coordinated. Most synaptic proteins are involved in rich protein interaction networks. Overall, the number of interacting proteins and the degrees of sequence conservation between human and insects are closely correlated. Such a correlation holds for exocytotic but not for endocytotic proteins.

Conclusion

This comparative study of human with insects sheds light on the composition and assembly of protein complexes in the synapse. Specifically, the nature of the protein interaction graphs differentiate exocytotic from endocytotic proteins and suggest unique evolutionary constraints for each set. General principles in the design of proteins of the presynaptic site can be inferred from a comparative study of human and insect genomes.
Analysis of 142 genes resolves the rapid diversification of the rice genus
Authors: Zou Xin-Hui , Zhang Fu-Min , Zhang Jian-Guo , Zang Li-Li , Tang Liang , Wang Jun , Sang Tao , Ge Song
Published: March 2008

Background

The completion of rice genome sequencing has made rice and its wild relatives an attractive system for biological studies. Despite great efforts, phylogenetic relationships among genome types and species in the rice genus have not been fully resolved. To take full advantage of rice genome resources for biological research and rice breeding, we will benefit from the availability of a robust phylogeny of the rice genus.

Results

Through screening rice genome sequences, we sampled and sequenced 142 single-copy genes to clarify the relationships among all diploid genome types of the rice genus. The analysis identified two short internal branches around which most previous phylogenetic inconsistency emerged. These represent two episodes of rapid speciation that occurred approximately 5 and 10 million years ago (Mya) and gave rise to almost the entire diversity of the genus. The known chromosomal distribution of the sampled genes allowed the documentation of whole-genome sorting of ancestral alleles during the rapid speciation, which was responsible primarily for extensive incongruence between gene phylogenies and persisting phylogenetic ambiguity in the genus. Random sample analysis showed that 120 genes with an average length of 874 bp were needed to resolve both short branches with 95% confidence.

Conclusion

Our phylogenomic analysis successfully resolved the phylogeny of rice genome types, which lays a solid foundation for comparative and functional genomic studies of rice and its relatives. This study also highlights that organismal genomes might be mosaics of conflicting genealogies because of rapid speciation and demonstrates the power of phylogenomics in the reconstruction of rapid diversification.
Experimenting with Spirituality: AnalyzingThe God Genein a Nonmajors Laboratory Course
Authors: Silveira Linda A.
Published: March 2008

References linking genes to complex human traits, such as personality type or disease susceptibility, abound in the news media and popular culture. In his book The God Gene: How Faith is Hardwired into Our Genes, Dean Hamer argues that a variation in the VMAT2 gene plays a role in one's openness to spiritual experiences. In a nonmajors class, we read and discussed The God Gene and conducted on a small scale an extension of the study it describes. Students used polymerase chain reaction to replicate a portion of their VMAT2 genes, and they analyzed three polymorphic sites in the sequence of these products. Associations between particular VMAT2 alleles and scores on a personality test were assessed by t test. The course, of which this project was a major part, stimulated student learning; scores on a test covering basic genetic concepts, causation/correlation, and laboratory methodology improved after completion of the course. In a survey, students reported the laboratory project aided their learning, especially in the areas of statistics and the linking of genes to behaviors. They reported high levels of engagement with the project, citing in particular its personal nature as motivating their interest.
More than a Picture: Helping Undergraduates Learn to Communicate through Scientific Images
Authors: Watson Fiona L. , Lom Barbara
Published: March 2008

Images are powerful means of communicating scientific results; a strong image can underscore an experimental result more effectively than any words, whereas a poor image can readily undermine a result or conclusion. Developmental biologists rely extensively on images to compare normal versus abnormal development and communicate their results. Most undergraduate lab science courses do not actively teach students skills to communicate effectively through images. To meet this need, we developed a series of image portfolio assignments and imaging workshops in our Developmental Biology course to encourage students to develop communication skills using images. The improvements in their images over the course of the semester were striking, and on anonymous course evaluations, 73% of students listed imaging skills as the most important skill or concept they learned in the course. The image literacy skills acquired through simple lab assignments and in-class workshops appeared to stimulate confidence in the student's own evaluations of current scientific literature to assess research conclusions. In this essay, we discuss our experiences and methodology teaching undergraduates the basic criteria involved in generating images that communicate scientific content and provide a road map for integrating this curriculum into any upper-level biology laboratory course.
Identification and functional characterization of a bovine orthologue to DC-SIGN
Authors: Yamakawa Yoshika , Pennelegion Christopher , Willcocks Samuel , Stalker Amanda , MacHugh Niall , Burt Dave , Coffey Tracey J , Werling Dirk
Published: March 2008

Dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN) C-type lectin is almost exclusively expressed at the cell surface of DC. In addition to its normal function facilitating contact of DC with T cells, DC-SIGN has been shown to bind a variety of pathogens, including Mycobacterium bovis, and HIV-1 envelope protein gp120. In this study, we identified the bovine ortholog of the human DC-SIGN gene within the bovine genome, which exists as a single copy. PCR amplified a product, showing a 100% match with the predicted sequences as well as a sequence predicted to be similar to that of SIGNR7. Furthermore, a protein with the same molecular weight as human DC-SIGN was detected by Western blot in cell lysate derived from bovine DC. To characterize this molecule functionally, the uptake of FITC-labeled OVA and FITC-labeled gp120 (FITC-gp120) by bovine and human DC was assessed. FITC-gp120 was shown to bind to bovine DC in a time- and temperature-dependent manner. Binding was blocked by a polyclonal anti-DC-SIGN antibody but not by a control antibody. Furthermore, blocking of this molecule also reduced the binding of M. bovis bacillus Calmette-Guerin expressing GFP. Confocal microscopy showed that DC-SIGN was expressed on the surface of bovine DC. Subsequent pulse-chase studies revealed that FITC-gp120 was internalized by bovine monocyte-derived DC as early as 10 min. Thus, there is evidence of a DC-SIGN-like molecule expressed specifically by bovine DC. This molecule may play an important role in the infection of bovine (DC) cells with M. bovis.
Wild-Type KRAS Is Required for Panitumumab Efficacy in Patients With Metastatic Colorectal Cancer
Authors: Amado Rafael G. , Wolf Michael , Peeters Marc , Van Cutsem Eric , Siena Salvatore , Freeman Daniel J. , Juan Todd , Sikorski Robert , Suggs Sid , Radinsky Robert , Patterson Scott D. , Chang David D.
Published: March 2008

Purpose

Panitumumab, a fully human antibody against the epidermal growth factor receptor (EGFR), has activity in a subset of patients with metastatic colorectal cancer (mCRC). Although activating mutations in KRAS, a small G-protein downstream of EGFR, correlate with poor response to anti-EGFR antibodies in mCRC, their role as a selection marker has not been established in randomized trials.

Patients and Methods

KRAS mutations were detected using polymerase chain reaction on DNA from tumor sections collected in a phase III mCRC trial comparing panitumumab monotherapy to best supportive care (BSC). We tested whether the effect of panitumumab on progression-free survival (PFS) differed by KRAS status.

Results

KRAS status was ascertained in 427 (92%) of 463 patients (208 panitumumab, 219 BSC). KRAS mutations were found in 43% of patients. The treatment effect on PFS in the wild-type (WT) KRAS group (hazard ratio [HR], 0.45; 95% CI: 0.34 to 0.59) was significantly greater (P < .0001) than in the mutant group (HR, 0.99; 95% CI, 0.73 to 1.36). Median PFS in the WT KRAS group was 12.3 weeks for panitumumab and 7.3 weeks for BSC. Response rates to panitumumab were 17% and 0%, for the WT and mutant groups, respectively. WT KRAS patients had longer overall survival (HR, 0.67; 95% CI, 0.55 to 0.82; treatment arms combined). Consistent with longer exposure, more grade III treatment-related toxicities occurred in the WT KRAS group. No significant differences in toxicity were observed between the WT KRAS group and the overall population.

Conclusion

Panitumumab monotherapy efficacy in mCRC is confined to patients with WT KRAS tumors. KRAS status should be considered in selecting patients with mCRC as candidates for panitumumab monotherapy.
Acquisition of relations between the conceptual and linguistic dimensions of linearization in descriptive text composition in grades five to nine: A comparison with oral production
Authors: Favart Monik , Passerault Jean‐Michel
Published: March 2008

The present study looked at how children establish a relationship between the conceptual and linguistic dimensions of linearization in descriptive text composition. Written productions were compared with oral ones. French‐speaking participants, drawn from the fifth, seventh, and ninth grades, produced both a written and an oral description of a picture divided up into five clusters of specific units. This material made it possible to distinguish between the macro‐structural and micro‐structural levels of the resulting productions. The conceptual dimension of linearization was levelled out: participants were only selected if their texts reflected the hierarchical structure of the referent, successively describing the five clusters. The linguistic dimension of linearization was tested by comparing the use made of connectives in both modalities and analysing punctuation marks and speech pauses according to the modality. We established a specific classification for the analysis of spatial connectives, distinguishing between absolute and relative connectives. As expected, the proportion of texts reflecting the hierarchy of the referent increased through grade levels. From fifth grade onwards, and in both modalities, this hierarchy was marked by appropriate linguistic devices: at the macro‐structural level, absolute spatial connectives were mainly used, as well as strong punctuation marks in writing and longer pauses in speech. At the micro‐structural level, relations were mainly marked by relative spatial connectives. A grade level effect was observed, mainly in the written texts. However, results showed that, in writing as well as in speech, the management of the linguistic component of discourse linearization was, to a considerable degree, determined by the conceptual one.
Considerations for Development of Surrogate Endpoints for Antifracture Efficacy of New Treatments in Osteoporosis: A Perspective
Authors: Bouxsein Mary L , Delmas Pierre D
Published: March 2008

Because of the broad availability of efficacious osteoporosis therapies, conduct of placebo-controlled trials in subjects at high risk for fracture is becoming increasing difficult. Alternative trial designs include placebo-controlled trials in patients at low risk for fracture or active comparator studies, both of which would require enormous sample sizes and associated financial resources. Another more attractive alternative is to develop and validate surrogate endpoints for fracture. In this perspective, we review the concept of surrogate endpoints as it has been developed in other fields of medicine and discuss how it could be applied in clinical trials of osteoporosis. We outline a stepwise approach and possible study designs to qualify a biomarker as a surrogate endpoint in osteoporosis and review the existing data for several potential surrogate endpoints to assess their success in meeting the proposed criteria. Finally, we suggest a research agenda needed to advance the development of biomarkers as surrogate endpoints for fracture in osteoporosis trials. To ensure optimal development and best use of biomarkers to accelerate drug development, continuous dialog among the health professionals, industry, and regulators is of paramount importance.
Abortion in the United States: Incidence and Access to Services, 2005
Authors: Jones Rachel K. , Zolna Mia R. S. , Henshaw Stanley K. , Finer Lawrence B.
Published: March 2008

CONTEXT:  Accurate information about abortion incidence and services is necessary to monitor levels of unwanted pregnancy and women’s ability to access abortion services.

METHODS:  All known abortion providers in the United States were contacted for information about abortion services in 2004 and 2005. This information, along with data from the U.S. Census Bureau, was used to examine national and state trends in numbers of abortions and abortion rates, proportions of counties and metropolitan areas without an abortion provider, and accessibility of abortion services.

RESULTS:  An estimated 1.2 million abortions were performed in the United States in 2005, 8% fewer than in 2000. The abortion rate in 2005 was 19.4 per 1,000 women aged 15–44; this rate represents a 9% decline from 2000. There were 1,787 abortion providers in 2005, only 2% fewer than in 2000. Some 87% of U.S. counties, containing 35% of women aged 15–44, did not have an abortion provider in 2005. Early medication abortion, offered by an estimated 57% of known providers, accounted for 13% of abortions (and for 22% of abortions before nine weeks’ gestation). The average amount paid for an abortion at 10 weeks was $413—after adjustment for inflation, $11 less than in 2001.

CONCLUSION:  The numbers of abortions and the abortion rate continued their long‐term decline through 2005. Reasons for this trend are unknown but may include improved access to and use of contraceptives or decreased access to abortion services.
Older Sexual Partners During Adolescence: Links to Reproductive Health Outcomes in Young Adulthood
Authors: Ryan Suzanne , Franzetta Kerry , Manlove Jennifer S. , Schelar Erin
Published: March 2008

CONTEXT:  Sex at a young age with an older partner has been linked to poor reproductive health outcomes during adolescence, but minimal research has examined the influence of teenagers’ having an older sexual partner on reproductive health outcomes during the transition to young adulthood.

METHODS:  Logistic regression and contrast analyses of three waves of data from the National Longitudinal Study of Adolescent Health were used to examine whether individuals who had had sex before age 16 with a partner at least three years their senior were at increased risk of becoming teenage or unmarried parents or of contracting an STD by young adulthood.

RESULTS:  Ten percent of females and 2% of males had had early sex with an older partner. These females were more likely to acquire an STD as young adults than were those whose riskiest relationship was before age 16 with a similar‐aged partner (odds ratio, 2.1) or at age 16 or later with a similar‐aged or older partner (2.4 and 2.6, respectively). For males, having sex before 16, regardless of partner age, was associated with an elevated STD risk (odds ratio, 1.9), although controlling for relationship history characteristics attenuated the association.

CONCLUSIONS:  Adolescents, particularly young adolescents, should be made aware of the potential risks associated with having older sexual partners. In particular, program providers should be alerted that females who engage in early sexual activity with older partners are at especially high risk of experiencing adverse reproductive health consequences.
Sexual Behavior of Single Adult American Women
Authors: Lindberg Laura Duberstein , Singh Susheela
Published: March 2008

CONTEXT:  Public policies promoting abstinence until marriage attempt to influence the sexual behavior of the more than 18 million American women who are currently single. An analysis of these women’s behavior is needed to inform policies that are responsive to their sexual and reproductive health needs.

METHODS:  Sexual behaviors, risk factors and reproductive health needs were examined among a nationally representative sample of 6,493 women aged 20–44 from the 2002 National Survey of Family Growth. Paired t tests were used to assess differences among single, married and cohabiting women by selected demographic, behavioral and risk measures.

RESULTS:  Thirty‐six percent of women aged 20–44 are single, and nine in 10 single women are sexually experienced. Seventy percent of the latter women are currently sexually active; on average, they had intercourse in seven of the last 12 months. A higher proportion of single women (22%) than of cohabiting (9%) or married women (2%) have had two or more partners in the past year, and half of single women are at risk of unintended pregnancy. Furthermore, single women and cohabiting women are more likely to lack health insurance than are married women (21–25% vs. 12%).

CONCLUSIONS:  Because of the high level of sexual activity among single adult women, providers must address their reproductive health care needs and offer appropriate counseling and services. Government policies aimed at encouraging adult women to have sex only within marriage appear out of touch with the reality of the sexual behavior of single women.
Effects of a School‐Based, Theory‐Driven HIV and Pregnancy Prevention Curriculum
Authors: Zimmerman Rick S. , Cupp Pamela K. , Donohew Lewis , Kristin Sionéan C. , Feist‐Price Sonja , Helme Donald
Published: March 2008

CONTEXT:  Although a number of interventions are effective at reducing risky adolescent sexual behavior, it may be possible to make them even more effective by addressing adolescents’ approaches to risk‐taking.

METHODS:  Schools were assigned to teach one of three curricula in a quasi‐experimental intervention study: the school’s standard pregnancy and HIV prevention curriculum; the Reducing the Risk curriculum; or a modified Reducing the Risk curriculum, adapted for high sensation seekers and impulsive decision makers. A sample of 1,944 students from 17 schools was surveyed at three time points between 1995 and 1997. Mixed models regression and logistic regression were used to examine the difference in impact among curricula.

RESULTS:  Differences in the impact of the original and modified Reducing the Risk interventions were not significant for the total sample or for high sensation seekers and impulsive decision makers separately. Students from both intervention groups demonstrated short‐term improvements in knowledge; students who received their schools’ standard curriculum were significantly more likely than those assigned to either intervention to have initiated sexual intercourse by the third time point (odds ratio, 2.4).

CONCLUSION:  More work is necessary to understand the best ways to design classroom messages that will be effective in reducing the risk behaviors of high sensation seekers and impulsive decision makers.
Geo-cultural proximity, genre exposure, and cultivation
Authors: Hetsroni Amir
Published: March 2008

This work investigates the influence of geo-cultural proximity and exposure to news and crime-action drama on the cultivation effect. A content analysis of prime-time programming (N = 63 hours) was used to compose questions about the prevalence of policemen, lawyers, and salesmen in the USA and Israel. A sample of 655 students answered the questions. Viewing of American programming is significantly correlated with a tendency to hold a biased estimation of the prevalence of all three occupations in America in a manner that resembles the world of TV content. Viewing of Israeli programs has no such impact. Viewing of news and crime-action drama and general viewing have no systematic influence on the estimations made about any of the countries.
Kritik der Tatherrschaftslehre
Authors: Haas Volker
Published: March 2008

I. Einleitung

Die Theorie der Tatherrschaft, die ganz maßgeblich von Roxin ausgearbeitet und kasuistisch ausgeformt worden ist, stellt in Deutschland gegenwärtig noch die ganz herrschende Doktrin im Bereich der strafrechtlichen Beteiligungslehre dar. Partiell wird sie nunmehr auch von der Rechtsprechung anerkannt, wie sich am deutlichsten in der Übernahme der Rechtsfigur der mittelbaren Täterschaft kraft organisierter Machtapparate in den Mauerschützenfällen zeigt. Ihr unaufhaltsam scheinender Siegeszug ist jedoch in jüngster Zeit etwas ins Stocken geraten. Zu beobachten ist zunehmende Kritik, die allerdings weniger das Lehrgebäude in seinen Grundfesten insgesamt, sondern vielmehr einzelne seiner Facetten betrifft. Es besteht daher Anlass, die Voraussetzungen und Annahmen zu hinterfragen, auf denen die Tatherrschaftslehre als Ganzes fußt. Im Folgenden soll zunächst in einem ersten Schritt kurz skizziert werden, auf welche Weise die Tatherrschaftslehre ein Gegenmodell zum subjektiven Täterbegriff einerseits und zum formalobjektiven Täterbegriff andererseits entworfen hat, um dann in einem zweiten Schritt Unstimmigkeiten der Tatherrschaftslehre aufzuzeigen. Abschließend werden einige Konsequenzen skizziert, die sich aus den geäußerten Bedenken ergeben. Insbesondere wird versucht zu begründen, dass wir des Rückgriffs auf den berechtigten Nukleus der subjektiven Lehre (wenn auch in modifizierter Gestalt) durchaus bedürfen.
One-Month Adherence in Children With New-Onset Epilepsy: White-Coat Compliance Does Not Occur
Authors: Modi Avani C. , Morita Diego A. , Glauser Tracy A.
Published: March 2008

OBJECTIVES. Adherence to antiepileptic drug therapy plays an important role in the effectiveness of pharmacologic treatment of epilepsy. The purpose of this study was to use an objective measure of adherence to (1) document patterns of adherence for the first month of therapy for children with new-onset epilepsy, (2) examine differences in adherence by demographic and epilepsy variables, and (3) determine whether treatment adherence improves for a short time before a clinic visit (eg, “white-coat compliance”).

METHODS. Participants included 35 children with new-onset epilepsy (mean age: 7.2 years; 34% female; 66% white) and their caregivers. Children had a diagnosis of partial (60%), generalized (29%), or unclassified (11%) epilepsy. Adherence to treatment was electronically monitored with Medication Event Monitoring System TrackCap, starting with the first antiepileptic drug dose. Adherence was calculated across a 1-month period and for the 1, 3, and 5 days before and 3 days after the clinic appointment.

RESULTS. Adherence for the first month of treatment in children with new-onset epilepsy was 79.4%. One-month adherence was higher in children of married parents and those with higher socioeconomic status but did not correlate with child's gender, age, epilepsy type, prescribed medication, seizure frequency, or length of time since seizure onset. Adherence across the entire 1-month period was not different from adherence for the 1, 3, or 5 days before or 3 days after the clinic visit.

CONCLUSIONS. Poor adherence seen for children with new-onset epilepsy during the first month of antiepileptic drug therapy is a cause for concern. Several demographic variables influence adherence to treatment, whereas the proximity to a clinic visit does not. Additional studies are needed to document whether this trend continues longitudinally and determine the clinical impact of poor adherence.
Utility of Total Lower Extremity Radiography Investigation of Nonweight Bearing in the Young Child
Authors: Baron Christopher M. , Seekins Jayne , Hernanz-Schulman Marta , Yu Chang , Kan J. Herman
Published: March 2008

OBJECTIVES. The purpose of this work was to determine the utility of total lower extremity radiographs versus dedicated tibia radiographs in the evaluation of the young child presenting with nonweight bearing without localizing signs.

METHODS. This was an institutional review board-approved retrospective review of 263 consecutive patients between the ages of 9 months and 4 years who were referred for total lower extremity radiography between September 29, 2001, and November 7, 2006. Among these, a total of 133 study subjects met inclusion criteria of presentation with nonweight bearing without localizing signs or history of previous trauma. The control population was selected from 1089 consecutive patients between the ages of 9 months and 4 years evaluated from January 5, 1999 and December 8, 2006, who had only tibia radiographs at presentation. From this group, a final control population of 128 patients was selected with similar presentation of nonweight bearing without localizing signs or history of previous trauma. Causes of nonweight bearing were recorded for both groups based on radiograph findings and additional studies performed during workup.

RESULTS. At initial presentation, fractures were present in 13 study patients (9.8%) and in 23 control patients (17.9%). Total fractures (when including follow-up) were present in 14 study patients (10.5%) and in 26 control patients (20.3%). Fractures were located in the tibia alone in 100% of patients in the study group. Extratibial fracture (metatarsal) was present in 1 patient in the control group (0.7%). Among the study group, additional diagnoses included rickets (n = 1), cerebellar ataxia (n = 1), and discitis with epidural abscess (n = 1).

CONCLUSIONS. Our study findings indicate that the diagnostic value of total lower extremity radiography is similar to dedicated tibia radiography in the workup of the nonweight-bearing young child without trauma history or localizing signs. Radiation and cost savings can be realized by reserving additional radiographs for patients with high clinical suspicion and normal findings on dedicated tibia radiography.
Preparation and properties of spray dried precursor powder for melt-processed bulk YBCO ceramics
Authors: Lo Wai , Cardwell David A. , Dung Shiang-Lung , Barter Richard G.
Published: March 2008

YBa2Cu3O7−δ precursor powder suitable for the fabrication of melt-processed ceramic has been prepared by spray drying and subsequent calcination. The dehydration and decomposition processes in the nitrate-based spray-dried powder and the formation processes of the YBa2Cu3O7−δ and Y2BaCuO5 phases have been studied in detail using thermal analysis and powder x-ray diffractometry. The morphology, microstructure, and size distribution of the particles in the calcined powder have been investigated using high resolution scanning electron microscopy and particle size analysis and found to contain a significant proportion of submicron sized particles of Y2BaCuO5. Melt-processed samples prepared using the spray-dried powder have been observed to exhibit a significantly finer distribution of the 211 phase than is typically obtained in similar specimens prepared via a mixed oxide route. This provides direct evidence of the suitability of spray-dried precursor powder for the fabrication of large grain, high Jc melt-processed YBCO ceramics.
The microstructure and creep deformation of hot-pressed Si3N4 with different amounts of sintering additives
Authors: Yoon Sang-Young , Akatsu Takashi , Yasuda Eiichi
Published: March 2008

Compressive creep deformation of hot-pressed silicon nitride with different amounts of grain boundary glassy phase was investigated at 1300–1400 °C under 30–100 MPa. The stress exponent of the creep rate was determined to be nearly unity. The apparent activation energy of silicon nitride with a larger amount of glassy phase was measured to be about 700 kJ/mole, and that with a smaller amount of glassy phase was found to be 400 kJ/mole. In addition, the microstructural observation found that no cavity appeared and grain boundary glass was recrystallized during creep test. Thus, the rate-limiting steps in solution/precipitation creep mechanism change from the solution-reprecipitation of Si3N4 grains to the diffusion through the grain boundary with increasing the amount of glassy phase.
Characterization of highly oriented (110) TiN films grown on epitaxial Ge/Si(001) heterostructures
Authors: Zheleva T. , Oktyabrsky S. , Jagannadham K. , Vispute R. D. , Narayan J.
Published: March 2008

The characteristics of epitaxial growth of titanium nitride films on Ge/Si(001) have been studied. The growth of titanium nitride and germanium films on (001)Si was carried out in situ in a high vacuum chamber (<10−7 Torr) using a multitarget stage in a pulsed laser deposition system. Electrical resistivity, stoichiometry, crystallinity, and epitaxial relationships as a function of deposition temperature have been studied. Electrical resistivity of the titanium nitride films grown at deposition temperatures in the range of 450 °C–750 °C was measured using a four-point probe. The stoichiometry of these films was investigated using Auger electron spectroscopy and Raman spectroscopy. The crystalline quality and epitaxial nature of TiN films grown at different substrate temperatures were characterized using x-ray diffraction and transmission electron microscopy. Highly oriented titanium nitride films with (110) orientation were obtained on Ge(001) film when the substrate temperature was maintained between 550 °C and 650 °C. The epitaxial growth of the titanium nitride films was found to be a function of two-dimensional or three-dimensional growth mode of germanium film on silicon (001) substrate. Titanium nitride films grown at a substrate temperature of 650 °C exhibited the lowest room temperature resistivity (26 μΩ-cm), highest nitrogen content (close to stoichiometry), and the best epitaxiality with the Ge(001) films on Si(001). The epitaxial relationships for the TiN/Ge/Si(001) heterostructure are found to be [001]TiN‖ [110]Ge‖ [110]Si and [110]TiN‖ [110] Ge‖ [110]Si. To explain the epitaxial growth in a large mismatch system (∼28%) such as TiN/Ge(001), the domain matching mechanism is proposed. Domains of size four (001)TiN by seventeen (220)TiN in the titanium nitride film match closely with domains of size three (220)Ge by sixteen (220)Ge in the germanium film, respectively. The lattice matching epitaxy involving a 4% mismatch between Ge and Si provides a mechanism for epitaxial growth of Ge on Si(001).
Rapidly quenched Y–Pd–B–C borocarbides: Identification of the superconducting metastable phases
Authors: Ström V. , Kim K. S. , Grishin A. M. , Rao K. V.
Published: March 2008

Rapidly quenched melt-spun ribbons of palladium-based borocarbides with large fractions of the superconducting phase (Tc > 20 K) have been obtained. Superconductivity in the Pd-based alloys seems to be metastable and exists only in the rapidly quenched state. Thus, while in the as-cast state the YPd2B2C ingot is found to be paramagnetic, the rapidly quenched ribbon superconducts and has a simple XRD pattern characteristic for a fcc lattice with a lattice parameter of 4.15 Å. A systematic study in an annealing sequence shows decay of the superconducting phase above 750 °C. The reduction in the integral intensities of XRD fcc peaks correlates well with the loss of the superconducting fraction on successive annealing. The recently reported tetragonal phase, attributed to the superconducting state in this system, is not found in any of our rapidly quenched samples. We present the phase diagrams indicating the optimum composition regimes for superconductivity in the Y–Ni–B–C and Y–Pd–B–C systems. From our magnetic data the values for the upper critical field Hc2(0), and the coherence length ξ(0) are estimated to be 10 Tesla and 57 Å, respectively, for the rapidly quenched YPd2B2C superconducting ribbons.
Effects of lanthanum modification on rhombohedral Pb(Zr1−xTix)O3 ceramics: Part I. Transformation from normal to relaxor ferroelectric behaviors
Authors: Dai Xunhu , Xu Z. , Li Jie-Fang , Viehland Dwight
Published: March 2008

The interruption of long-range polar order in rhombohedral ferroelectricPb(Zr1−xTix)O3 (PZT) ceramics has been systematically studied by incorporating La onto the A-site of the perovskite (ABO3) structure for Zr/Ti ratios of 65/35 and 80/20 and various La contents. Studies have been performed by hot-stage transmission electron microscopy, dielectric spectroscopy, and Sawyer–Tower polarization (P-E) techniques. The evolution of a polar nanodomain state from a normal micron-sized domain state with increasing La content was observed. The emergence of this polar cluster state was characterized by the onset of strong frequency dispersion in the dielectric response, indicative of relaxor behavior. The La content that drives the structure into the relaxor state was found to be related to the lattice distortion of the undoped base composition.
Sol-gel synthesis of rare-earth-doped fluoride glass thin films
Authors: Ballato John , Dejneka Matthew , Riman Richard E. , Snitzer Elias , Zhou Weimin
Published: March 2008

This paper describes ZBLA fluoride glass thin films produced via an inexpensive, low-temperature reactive atmosphere sol-gel approach. Luminescence from erbium at 1.55 μm has been observed in x-ray-amorphous doped films deposited on calcium fluoride, polyimide, sapphire, and silicon substrates. Fluorescence studies of the erbium 4S3/2 → 4I13/2 transition, a characteristic emission for a reduced phonon energy host, were conducted for both sol-gel-derived films and conventionally prepared glass rods. The peak intensity observed from the sol-gel films was blue-shifted by 16 nm with a FWHM value approximately half that measured for the melt-quenched rods. Excitation studies indicate that, unlike conventionally prepared glasses, sol-gel materials suffer from nonradiative relaxation of the 4S3/2 excited state to the 4I9/2 level, where subsequent radiative emission to the 4I15/2 ground state occurs. The proposed source of the quenching mechanism are remnant species inherent to the sol-gel process. While this causes the luminescence behavior of rare-earth-doped sol-gel-derived fluoride materials to be similar to oxide hosts, these remnant species modify the branching ratios, resultantly leading to a novel 824 nm emission when excited at 488 nm.
Investigation of the crystallization of ZrO2 (Y2O3 3 mol%) nanopowder
Authors: Liu Huiwen , Xue Qunji
Published: March 2008

The coprecipitation technique has been used to prepare ZrO2 (Y2O3 3 mol %) nanopowder. The influence of residual NH4Cl and pH value on the crystallization of ZrO2 (Y2O3 3 mol %) nanopowder have been investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), x-ray diffraction (XRD), infrared spectrometry (IR), and transmission electron microscopy (TEM) techniques. The IR spectra proved that the presence of residual NH4Cl increased the amount of the hydroxo group. This led to serious gel agglomerate and free enthalpy decrease. Therefore, the crystallization of ZrO2 (Y2O3 3 mol%) nanopowder is greatly influenced by the residual NH4Cl. While there is no residual NH4Cl, the crystallization takes place at 445 °C and is an exothermic process. On the contrary, with NH4Cl the crystallization takes place at 376 °C and is an endothermic process. However, the pH value does not influence the crystallization of ZrO2 (Y2O3 3 mol%) nanopowder.
High resolution studies of crystalline damage induced by lapping and single-point diamond machining of Si(100)
Authors: Kunz R. R. , Clark H. R. , Nitishin P. M. , Rothschild M. , Ahern B. S.
Published: March 2008

Si(100) wafers were prepared by both diamond turning and standard lapping and polishing techniques. For single-point diamond machining, characterization of subsurface damage resulting from ductile-regime machining identified a plastic-yield zone consisting of slip planes and dislocation networks extending 1 to 3 μm deep despite surface root-mean-square roughness values as low as 5 nm. For conventional lapping and polishing using alumina grit, a transition from brittle to ductile yield was observed for grit sizes less than 300 nm. Subsurface damage depth correlated to surface roughness in a more straightforward manner than for the diamond point machining. Completely damage-free material removal was obtained only when a chemical component to the polishing was present.
Synthesis of mullite coatings by chemical vapor deposition
Authors: Mulpuri Rao P. , Sarin Vinod K.
Published: March 2008

Formation of mullite on ceramic substrates via chemical vapor deposition was investigated. Mullite is a solid solution of Al2O3 and SiO2 with a composition of 3Al2O3 · 2SiO2. Thermodynamic calculations performed on the AlCl3–SiCl4–CO2–H2 system were used to construct equilibrium chemical vapor deposition (CVD) phase diagrams. With the aid of these diagrams and consideration of kinetic rate limiting factors, initial process parameters were determined. Through process optimization, crystalline CVD mullite coatings have been successfully grown on SiC and Si3N4 substrates. Results from the thermodynamic analysis, process optimization, and effect of various process parameters on deposition rate and coating morphology are discussed.
Origin of the ϕ ∼ ±9° peaks in YBa2Cu3O7−δ films grown on cubic zirconia substrates
Authors: Schlom D. G. , Hellman E. S. , Hartford E.H. , Eom C.B. , Clark J. C. , Mannhart J.
Published: March 2008

The c-axis oriented YBa2Cu3O7−δ films grown on (001) yttria-stabilized cubic zirconia (YSZ) substrates often contain domains whose in-plane alignment is rotated approximately 9° from the cube-on-cube epitaxial relationship, in addition to the more commonly observed 0° and 45° in-plane rotations. We have investigated the origin of this ∼9° orientation using in situ electron diffraction during growth and ex situ 4-circle x-ray diffraction. Our results indicate that the ∼9° orientation provides the most favorable lattice match between the interfacial (110)-oriented BaZrO3 epitaxial reaction layer, which forms between YBa2Cu3O7−δ and the YSZ substrate. If epitaxy occurs directly between YBa2Cu3O7−δ and the YSZ substrate, i.e., before the BaZrO3 epitaxial reaction layer is formed, the 0° and 45° domains have the most favorable lattice match. However, growth conditions that favor the formation of the BaZrO3 reaction layer prior to the nucleation of YBa2Cu3O7−δ lead to an increase in ∼9° domains. The observed phenomenon, which results from epitaxial alignment between the diagonal of a square surface net and the diagonal of a rectangular surface net, is a general method for producing in-plane misorientations, and has also been observed for the heteroepitaxial growth of other materials, including (Ba, K)BiO3/LaAlO3. The YBa2Cu3O7−δ/YSZ case involves epitaxial alignment between [111]BaZrO3 and [110]YSZ, resulting in an expected in-plane rotation of 11.3° to 9.7° for fully commensurate and for fully relaxed (110)BaZrO3 on (001)YSZ, respectively.
X-ray photoelectron spectroscopy study of the interaction of methanol with polycrystalline copper oxide surface
Authors: Badrinarayanan S. , Mandale A. B. , Sainkar S. R.
Published: March 2008

Methanol decomposition on a clean polycrystalline copper oxide surface was studied by x-ray photoelectron spectroscopy (XPS). Methanol was adsorbed at 133 K and desorbed over a broad temperature range. When CuO was exposed to a very low dose of methanol vapor, dissociative adsorption takes place, leading to the formation of CH3O and H2O. This is attributed to the presence of preadsorbed oxygen on the CuO surface.
Stability of the Tl-1223 phases
Authors: Aselage T. L. , Venturini E. L. , Voigt J. A. , Miller D. J.
Published: March 2008

The thermodynamic stability of TlBa2Ca2Cu3O9–y (1223) and substitutionally related phases has been studied by performing extended high-temperature anneals in a two-zone furnace. This approach allows for independent control of each of the thermodynamic variables: the oxygen and thallous oxide partial pressures [P(O2) and P(Tl2O)], the sample temperature, and the sample composition. P(Tl2O) determines which of several superconducting phases form in the unsubstituted Tl–Ba–Ca–Cu–O system. TlBa2Ca2Cu3O9–y is stable only within a narrow window of P(Tl2O). Partially replacing Tl with Pb and Ba with Sr substantially increases the stability of the 1223 phase. The composition (TlxPb0.5) (Sr1.6Ba0.4)Ca2Cu3O9–y yields only the 1223 phase under two-zone conditions when P(Tl2O) exceeds a lower bound. The stability of Pb- and Sr-substituted 1223 relative to the 1212 phase is related to the substitutional stoichiometry, rather than P(Tl2O).
On the inhomogeneity of the crystallographic rolling texture of polycrystalline Fe3Al
Authors: Raabe D. , Keichel J.
Published: March 2008

An intermetallic Fe3Al alloy was cast, hot rolled, annealed (870 K), and finally quenched. After this treatment, the alloy had an imperfectly ordered B2 structure. The polycrystalline sample was then warm rolled at 800–830 K. The crystallographic texture of the rolled specimen was quantitatively studied within the range, ∈ = 20–80%. Even at large strains (∈ = 80%), recrystallization was not observed in the microstructure. It was found that the rolling texture of Fe3 Al is very inhomogeneous through the sample thickness. In the center layer, a large volume fraction of grains with a {111} lattice plane parallel to the sheet surface, {111}〈uvw〉, and a weak {001} 〈110〉 component were observed. In contrast, close to the sheet surface layer, a weak texture containing the {11 11 8} 〈4 4 11〉 and the {012} 〈110〉 orientations was formed. The results are interpreted in terms of the activation of {110} 〈111〉 and {112} 〈111〉 slip systems. The through-thickness texture gradient was attributed to the inhomogeneous strain distribution during rolling, leading to plane strain in the center layer and to shear strains close to the surface.
Powder x-ray diffraction of turbostratically stacked layer systems
Authors: Yang D. , Frindt R. F.
Published: March 2008

A special form of the Debye formula for calculating the powder x-ray diffraction of a turbostratically stacked layer system is derived, and calculated diffraction patterns for turbostratically stacked graphite and MoS2 layers are presented. Single-molecular-layer MoS2, prepared by exfoliation of lithium-intercalated MoS2 in water or alcohols, has been deposited on various supports, and x-ray diffraction patterns show that the restacking of the MoS2 layers can be perfectly turbostratic. The restacked MoS2 may or may not have water or organic bilayers between them, depending on the deposition conditions.