bluuebunny/crossref_metadata_2025 huggingface dataset:
Prenatal Testosterone Excess Reduces Sperm Count and Motility
Authors: Recabarren Sergio E. , Rojas-García Pedro P. , Recabarren Mónica P. , Alfaro Victor H. , Smith Rosita , Padmanabhan Vasantha , Sir-Petermann Teresa
Published: August 2008

The reproductive system is extremely susceptible to insults from exposure to exogenous steroids during development. Excess prenatal testosterone exposure programs neuroendocrine, ovarian, and metabolic deficits in the female, features seen in women with polycystic ovary disease. The objective of this study was to determine whether prenatal testosterone excess also disrupts the male reproductive system, using sheep as a model system. The extent of reproductive disruption was tested by assessing sperm quantity and quality as well as Leydig cell responsiveness to human chorionic gonadotropin. Males born to mothers treated with 30 mg testosterone propionate twice weekly from d 30 to 90 and with 40 mg testosterone propionate from d 90 to 120 of pregnancy (T-males) showed a significant reduction (P < 0.05) in body weight, scrotal circumference, and sperm count compared with control males. Mean straight line velocity of sperms was also lower in T-males (P < 0.05). Circulating testosterone levels in response to the human chorionic gonadotropin did not differ between groups. These findings demonstrate that exposure to excess testosterone during fetal development has a negative impact on reproductive health of the male offspring, raising concerns relative to unintended human exposure to steroidal mimics in the environment.
Consumer Surplus in Online Auctions
Authors: Bapna Ravi , Jank Wolfgang , Shmueli Galit
Published: August 2008

Despite the growing research interest in Internet auctions, particularly those on eBay, little is known about quantifiable consumer surplus levels in such mechanisms. Using an ongoing novel field experiment that involves real bidders participating in real auctions, and voting with real dollars, we collect and examine a unique data set to estimate consumer surplus in eBay auctions. The estimation procedure relies mainly on knowing the highest bid, which is not disclosed by eBay but is available to us from our experiment. At the outset we assume a private value second-price sealed-bid auction setting, as well as a lack of alternative buying options within or outside eBay. Our analysis, based on a sample of 4,514 eBay auctions, indicates that consumers extract a median surplus of at least $4 per eBay auction. This estimate is unbiased under the above assumptions; otherwise it is a lower bound. The surplus distribution is highly skewed given the diverse nature of the data. We find that eBay's auctions generated at least $7.05 billion in total consumer surplus in 2003 and could generate up to $7.68 billion if the private value sealed-bid assumption does not hold. We check for the validity of our assumptions and the robustness of our estimates using an additional data set from 2005 and a randomly sampled validation data set from eBay.
The Dissociation Between Monetary Assessment and Predicted Utility
Authors: Amir On , Ariely Dan , Carmon Ziv
Published: August 2008

We study the dissociation between two common measures of value—monetary assessment of purchase options versus the predicted utility associated with owning or consuming those options, a disparity that is reflected in well-known judgment anomalies and that is important for interpreting market research data. We propose that a significant cause of this dissociation is the difference in how these two types of evaluations are formed—each is informed by different types of information. Thus, dissociation between these two types of measures should not be interpreted as failure to map utility onto money, as such mapping is not really attempted. We suggest that monetary assessment tends to focus on the transaction in which the purchase alternative would be acquired or forgone (e.g., how fair the transaction seems), failing to adequately reflect the purchase alternative itself (e.g., the expected pleasure of owning or consuming it), which is what informs predicted utility judgments. We illustrate the value of this idea by deriving and testing empirical predictions of disparities in the impact of different types of information and manipulations on the two types of value assessment.
Market Share Constraints and the Loss Function in Choice-Based Conjoint Analysis
Authors: Gilbride Timothy J. , Lenk Peter J. , Brazell Jeff D.
Published: August 2008

Choice-based conjoint analysis is a popular marketing research technique to learn about consumers' preferences and to make market share forecasts under various scenarios for product offerings. Managers expect these forecasts to be “realistic” in terms of being able to replicate market shares at some prespecified or “base-case” scenario. Frequently, there is a discrepancy between the recovered and base-case market share. This paper presents a Bayesian decision theoretic approach to incorporating base-case market shares into conjoint analysis via the loss function. Because defining the base-case scenario typically involves a variety of management decisions, we treat the market shares as constraints on what are acceptable answers, as opposed to informative prior information. Our approach seeks to minimize the adjustment of parameters by using additive factors from a normal distribution centered at 0, with a variance as small as possible, but such that the market share constraints are satisfied. We specify an appropriate loss function, and all estimates are formally derived via minimizing the posterior expected loss. We detail algorithms that provide posterior distributions of constrained and unconstrained parameters and quantities of interest. The methods are demonstrated using discrete choice models with simulated data and data from a commercial market research study. These studies indicate that the method recovers base-case market shares without systematically distorting the preference structure from the conjoint experiment.
Functional Regression: A New Model for Predicting Market Penetration of New Products
Authors: Sood Ashish , James Gareth M. , Tellis Gerard J.
Published: August 2008

The Bass model has been a standard for analyzing and predicting the market penetration of new products. We demonstrate the insights to be gained and predictive performance of functional data analysis (FDA), a new class of nonparametric techniques that has shown impressive results within the statistics community, on the market penetration of 760 categories drawn from 21 products and 70 countries. We propose a new model called Functional Regression and compare its performance to several models, including the Classic Bass model, Estimated Means, Last Observation Projection, a Meta-Bass model, and an Augmented Meta-Bass model for predicting eight aspects of market penetration. Results (a) validate the logic of FDA in integrating information across categories, (b) show that Augmented Functional Regression is superior to the above models, and (c) product-specific effects are more important than country-specific effects when predicting penetration of an evolving new product.
Friction in Related-Party Trade When a Rival Is Also a Customer
Authors: Arya Anil , Mittendorf Brian , Yoon Dae-Hee
Published: August 2008

There are many circumstances in which manufacturers provide inputs to wholesale customers only to subsequently compete with these wholesale customers in the retail realm. Such dual distribution arrangements commonly suffer from excessive encroachment in that the manufacturer's ex post retail aggression is harmful ex ante because it undercuts potential wholesale profits. This paper demonstrates that with dual distribution, a manufacturer can benefit from decentralized control and the use of transfer prices above marginal cost. Although these arrangements often create coordination concerns, a moderate presence of such concerns permits the manufacturer to credibly convey to its wholesale customer that it will not excessively encroach on its retail territory. This, in turn, permits the manufacturer to reap greater wholesale profits. We also note that this force can point to a silver lining in arm's-length (parity) requirements on transfer pricing in that they can solidify commitments to a particular retail posture.
Reliability-Based System-Level Optimization of Bridge Maintenance and Replacement Decisions
Authors: Robelin Charles-Antoine , Madanat Samer M.
Published: August 2008

This paper addresses the problem of optimizing bridge maintenance and replacement (M&R) decisions for a heterogeneous system of facilities. The objective is to determine optimal M&R policies for each facility over a finite planning horizon based on the knowledge of the current facilities conditions and on the prediction of future conditions.

The system-level problem is based on the results of an M&R optimization problem for each facility. The results of the facility-level optimization are incorporated in a reliability-based, bottom-up, system-level formulation that provides recommendations for each individual facility. We derive sufficient conditions for optimality and prove the result for the continuous case. A parametric study shows that the results obtained in the discrete-case implementation of the solution are valid approximations of the continuous case results. The computational efficiency of the system-level solution makes the formulation suitable for systems of realistic sizes.
Pediatric Autoimmune Neuropsychiatric Disorders Associated With Streptococcus: Comparison of Diagnosis and Treatment in the Community and at a Specialty Clinic
Authors: Gabbay Vilma , Coffey Barbara J. , Babb James S. , Meyer Laura , Wachtel Carly , Anam Seeba , Rabinovitz Beth
Published: August 2008

OBJECTIVES. This study aimed to examine whether pediatric autoimmune neuropsychiatric disorders associated with streptococcus were appropriately diagnosed in the community and to determine subsequent rates of unwarranted use of antibiotic treatment for tics and obsessive-compulsive symptoms without the identification of an infection.

METHODS. The design was a retrospective, cross-sectional, observational study of 176 children and adolescents who were evaluated in a specialty program for tics, Tourette's disorder, and related problems. Previously published diagnostic criteria were used to establish the diagnosis of pediatric autoimmune neuropsychiatric disorders associated with streptococcus in our clinic.

RESULTS. Subjects were significantly less likely to receive a diagnosis of pediatric autoimmune neuropsychiatric disorders associated with streptococcus at the specialty clinic than in the community. In the community, subjects were significantly more likely to be treated with antibiotics or immunosuppressant medication if they received a diagnosis of pediatric autoimmune neuropsychiatric disorders associated with streptococcus. Of the 27 subjects with a community diagnosis of pediatric autoimmune neuropsychiatric disorders associated with streptococcus who were treated with antibiotics, 22 (82%) were treated without laboratory evidence of an infection; 2 were treated with immunomodulatory medications.

CONCLUSIONS. Our results support our hypothesis that pediatric autoimmune neuropsychiatric disorders associated with streptococcus are frequently diagnosed in the community without the application of all working diagnostic criteria. This phenomenon has resulted in unwarranted use of antibiotic treatment for tics/obsessive-compulsive disorder without evidence of laboratory infection.
Vitamin D Deficiency in Children and Its Management: Review of Current Knowledge and Recommendations
Authors: Misra Madhusmita , Pacaud Danièle , Petryk Anna , Collett-Solberg Paulo Ferrez , Kappy Michael ,   on behalf of the Drug and Therapeutics Committee of the Lawson Wilkins Pediatric Endocrine Society
Published: August 2008

Given the recent spate of reports of vitamin D deficiency, there is a need to reexamine our understanding of natural and other sources of vitamin D, as well as mechanisms whereby vitamin D synthesis and intake can be optimized. This state-of-the-art report from the Drug and Therapeutics Committee of the Lawson Wilkins Pediatric Endocrine Society was aimed to perform this task and also reviews recommendations for sun exposure and vitamin D intake and possible caveats associated with these recommendations.
Preschool Child Care Participation and Obesity at the Start of Kindergarten
Authors: Maher Erin J. , Li Guanghui , Carter Louise , Johnson Donna B.
Published: August 2008

OBJECTIVE. We examined the association between type of child care, participation in different types of child care in the year before kindergarten and the likelihood of obesity at the start of kindergarten.

METHODS. Using a nationally representative sample of 15 691 first-time kindergartners from the Early Childhood Longitudinal Study-Kindergarten Cohort, we used logistic regression to estimate the relationship between type of primary child care arrangement and children's likelihood of being obese at the start of kindergarten. Our models controlled for family and child characteristics associated with obesity and choice of child care. To examine differential effects of child care participation for groups at high risk for obesity, we tested interactions between children's ethnicity and income with primary type of child care.

RESULTS. At the start of kindergarten, 12% of the children were obese. Without controlling for other characteristics of children and families, children not in child care were significantly less likely and children in family, friend, and neighbor care were significantly more likely to be obese than children in other primary child care arrangements. White children were significantly less likely and Latino children more likely to be obese than children of other ethnic groups. After controlling for relevant child and family characteristics, children in family, friend, and neighbor care and non-Latino children in Head Start were more likely to be obese than children not in child care. For Latino children, however, participation in some types of nonparental child care had protective effects on their likelihood of being obese.

CONCLUSIONS. Primary type of child care is associated with children's obesity. For Latino children, who are at a greater risk of being obese, participation in nonparental child care seems to have a protective effect. These results suggest that child care settings may be an important site for policy intervention during a crucial developmental period. Efforts to help family, friend, and neighbor caregivers support children's physical health may be warranted.
Analysis of Rotavirus Antigenemia and Extraintestinal Manifestations in Children With Rotavirus Gastroenteritis
Authors: Sugata Ken , Taniguchi Koki , Yui Akiko , Miyake Fumi , Suga Sadao , Asano Yoshizo , Ohashi Masahiro , Suzuki Kyoko , Nishimura Naoko , Ozaki Takao , Yoshikawa Tetsushi
Published: August 2008

OBJECTIVE. This study was conducted to examine the association between rotavirus antigenemia and clinical features, particularly extraintestinal manifestations, and the association between serum cytokine levels and rotavirus antigen quantity.

METHODS. Sixty hospitalized children who received a diagnosis of acute rotavirus gastroenteritis were enrolled in this study. Paired serum samples were collected from the 60 children when admitted to and discharged from the hospital. Associations among viral antigen levels and fever, elevated transaminase levels, and seizures were evaluated to determine whether antigenemia correlated with disease severity. Viral antigen was measured by using an in-house enzyme-linked immunosorbent assay that detected VP6 antigen. A flow-cytometric bead array was used to measure serum cytokine levels.

RESULTS. Rotavirus antigen levels were significantly higher in serum collected at the time of hospital admission than at the time of discharge. Serum rotavirus antigen levels peaked on day 2 of the illness (2.02 ± 0.73), followed by a gradual decrease in antigen levels to nearly undetectable levels by day 6. The quantity of rotavirus antigen was significantly higher in serum collected from patients with fever than those without fever. The presence or absence of elevated transaminase levels and seizures was not associated with serum rotavirus antigen levels. A weak but significantly positive association was observed between interleukin 8 levels and antigenemia. A weak but significantly negative association was observed between interleukin 10 levels and antigenemia.

CONCLUSIONS. Rotavirus antigenemia is frequently observed in a patient's serum during the acute phase, and viral antigen levels change dramatically during the acute phase of the illness. Because patients with fever had higher rotavirus antigen levels, antigenemia severity might contribute to fever. The host immune response plays an important role in controlling antigenemia levels.
A Medical Home for Children With Insulin-Dependent Diabetes: Comanagement by Primary and Subspecialty Physicians—Convergence and Divergence of Opinions
Authors: Wegner Steven E. , Lathren Christine R. , Humble Charles G. , Mayer Michelle L. , Feaganes John , Stiles Alan D.
Published: August 2008

OBJECTIVE. The purpose of this work was to examine pediatricians' and endocrinologists' views about management for routine preventive and acute care, diabetes-specific care, and family education and care coordination for children with insulin-dependent diabetes.

METHODS. We conducted a mixed-mode survey of all of the pediatricians in 1 medicaid managed care network and all of the pediatric and adult endocrinologists who treat children with diabetes in North Carolina.

RESULTS. Of the 201 pediatricians surveyed, 132 responded (65%). Among the 61 endocrinologists who treat children, 59% replied. Nearly all of the respondents agreed that primary care physicians should have responsibility for routine primary care (eg, well-child checkups, treating minor illnesses or injuries, and immunizations). Likewise, large majorities favored endocrinologists as leads for diabetes-specific care (eg, 94% for training in use of an insulin pump and 82% for training in use of a glucometer). Many generalists and subspecialists reported that specific aspects of diabetes care should be comanaged (eg, 31% for tracking of hemoglobin A1c). However, large proportions of pediatricians and endocrinologists expressed differing opinions about the primary responsibility for family education and care coordination and for specific diabetes services. For example, 80% of endocrinologists saw subspecialists as leads for monitoring blood sugar levels, whereas 52% of pediatricians favored comanagement.

CONCLUSIONS. An effective medical home model of care depends on establishing clear lines of responsibility between the primary care physician and subspecialist. Our findings suggest that primary care physicians and subspecialists agree on who should lead most aspects of care for patients with insulin-dependent diabetes and that some aspects of care should be comanaged. However, primary care physicians and subspecialists did not agree either between or within disciplines on who should be more responsible for the basic aspect of monitoring of blood sugar levels. Approaches that recognize the appropriate division of care between primary care physicians and subspecialists, facilitate comanagement when it is needed, and reward the collaboration required to provide medical homes for patients should be investigated as models of care.
In-Hospital Falls of Newborn Infants: Data From a Multihospital Health Care System
Authors: Monson Sherry A. , Henry Erick , Lambert Diane K. , Schmutz Nancy , Christensen Robert D.
Published: August 2008

OBJECTIVE. The fall of a newborn infant to the hospital floor is an error that has received little or no attention in medical publications. We sought to analyze the circumstances surrounding all such falls that occurred in an 18-hospital health care system during a 3-year period.

METHODS. Information was located by using electronic and risk-management records. Demographic features, circumstances of the fall, and outcomes were tabulated for each event.

RESULTS. During the study period, 88774 live births occurred at the Intermountain Healthcare hospitals. Fourteen neonatal in-hospital falls were identified during this period (incidence estimate: 1.6 falls per 10000 births). Seven falls occurred when a parent, holding the infant in a hospital bed or reclining chair, fell asleep and the infant fell to the floor. Six of these 7 falls occurred between 1:30 am and 9:00 am. Four falls occurred in the delivery room, 2 in the hallway while a nurse was wheeling a bassinette, and 1 from an infant swing. No deaths occurred. One patient sustained a depressed skull fracture and was transported to the regional children's hospital. At hospital discharge, 13 of the 14 were reported to have a normal examination. No specific protocols for preventing in-hospital falls of neonates were in place.

CONCLUSIONS. If the incidence of a neonatal in-hospital fall in this study is representative, then 600 to 700 such falls occur annually in the United States. Relatively few scenarios explain the majority of falls. We speculate that the prevalence of this error could be reduced significantly by enacting programs aimed at eliminating or monitoring the most common circumstances under which these falls occur.
Imatinib treatment of our chronic myeloid leukemia patients
Authors: Egyed Miklós , Kollár Balázs , Rajnics Péter , Karádi Éva , Matolcsi András
Published: August 2008

A krónikus myeloid leukaemia a pluripotens haemopoeticus őssejt malignus klonális betegsége. A kórkép genetikai háttere a t(9;22) (Philadelphia kromoszóma), amely konvencionális citogenetikával a krónikus myeloid leukaemiás esetek több mint 90%-ában kimutatható, illetve a bcr-abl fúziós gén, amely tirozin-kináz-aktivitású fúziós fehérje szintézisét kódolja. Mai ismereteink alapján ez a folyamatosan aktív tirozin-kináz a krónikus myeloid leukaemia oka. Az imatinib alkalmazása jelentősen megváltoztatta a krónikus myeloid leukaemia kezelését. Az eddigi eredmények a betegség minden fázisában magas arányú citogenetikai választ igazoltak.
Módszerek:
A szerzők az általuk kezelt 21, krónikus fázisú krónikus myeloid leukaemiás beteg citogenetikai és molekuláris válaszait mutatják be. Közülük 13 esetében az imatinib első vonalbeli kezelés volt, a 7 másik beteg esetében több szerrel (interferon-alfa, citarabin, all-trans-retinoic acid) történt előkezelést követően alkalmazták. Minden krónikus myeloid leukaemiás beteg kezelését hidroxi-ureával kezdték a hematológiai remisszió eléréséig. Háromhavonta perifériás vérből kvantitatív valós idejű polimeráz láncreakciós vizsgálatot, 6 havonta csontvelő-aspirátumból konvencionális citogenetikai vizsgálatot végeztek.
Eredmények:
Hidroxi-urea-kezeléssel minden betegüknél hematológiai remissziót értek el. A továbbiakban minden betegük a 6. hónapra komplett citogenetikai és a 12. hónapra major molekuláris remisszióba jutott.
Következtetések:
Az imatinibkezelés mindkét csoportban az összes beteg esetében komplett citogenetikai és major molekuláris remissziót okozott. Az elsődlegesen imatinibkezelt betegek esetén észlelt gyors és mély citogenetikai válasz felveti a hidroxi-urea által elért jelentős sejtredukció esetleges szerepét.
Condensed water on superhydrophobic carbon films
Authors: Xiao Xingcheng , Cheng Yang Tse , Sheldon Brian W. , Rankin Janet
Published: August 2008

Nanostructured carbon materials, including carbon nanotubes, nanofibers, and nanowalls, exhibit a wide range of interesting properties dictated by the many different bonding configurations. Many of these materials can possess superhydrophobic behavior when water drops are placed on their surfaces: these drops have high contact angles and can roll freely on the surfaces, which is desirable for self-cleaning. In this work, we prepared porous carbon films using a microwave plasma enhanced chemical vapor deposition technique. These films showed superhydrophobicity with contact angle of 150°, which was explained by the synergetic effect of the highly rough surface combined with the hydrogen terminated edges of graphene sheets. However, the condensed water drops can behave differently: the drops did not roll readily. This behavior mimicked that of water on lotus leaves and further demonstrated that the reported superhydrophobic behavior is a function of how the water gets on to the surfaces.
Analysis of crystallization behavior of Fe48Cr15Mo14Y2C15B6 bulk metallic glass by synchrotron radiation
Authors: Baser T.A. , Baricco M. , Enzo S. , Vaughan G. , Yavari A.R.
Published: August 2008

The amorphous-to-crystalline transformation behavior of Fe48Cr15Mo14Y2C15B6 bulk metallic glasses was first investigated by high-temperature differential scanning calorimetry. Three events were detected with onset temperatures at 922, 975, and 1036 K, respectively. In situ synchrotron radiation x-ray diffraction patterns were collected during continuous heating and analyzed with the Rietveld approach. To describe simultaneously the amorphous fraction and crystallization products as a function of temperature, a paracrystalline structure-factor model was developed. It was included for quantitative evaluation of the amorphous phase, together with the structure factor of Cr23C6- and Fe3Mo3C-type phases observed during crystallization. Volume fractions of phases as well as lattice parameters, average lattice disorder, and crystallite size of the crystallized phases have been followed as a function of temperature. In this way, the structure evolution and thermal events have been closely inspected and accounted for by a crystallization mechanism.
Nanocrystalline ZrO2thin films on silicon fabricated by pulsed-pressure metalorganic chemical vapor deposition (PP-MOCVD)
Authors: Ramirez L. , Mecartney M.L. , Krumdieck S.P.
Published: August 2008

ZrO2films deposited on silicon (100) substrates using pulsed-pressure metalorganic chemical vapor deposition (PP-MOCVD) with zirconium n-propoxide (ZnP) Zr(OC3H7)4were dense and fully crystalline for substrate temperatures of 500 to 700 °C. Film thicknesses were 40 to 815 nm thick, measured after growth using ellipsometry and scanning electron microscopy (SEM). The growth rate was between 0.1 μm/h at 500 °C and 1 μm/h at 700 °C. Transmission electron microscopy (TEM) and x-ray diffraction (XRD) indicated an average grain size of 10 to 20 nm. There was a random orientation of cubic/tetragonal zirconia at the highest experimental temperature of 700 °C. SEM and atomic force microscopy (AFM) was used to characterize island height of discontinuous films in the initial stages of growth where defects in the substrate caused preferred nucleation of isolated particles. At later stages of growth, the average surface roughness of continuous films was 30 nm, which revealed a more uniform growth had developed. A growth model is proposed, and optimal growth conditions are suggested for targeted microstructures of ZrO2films.
Formation mechanisms and atomic configurations of nitride phases at the interface of aluminum nitride and titanium
Authors: Chiu Chia-Hsiang , Lin Chien-Cheng
Published: August 2008

Aluminum nitride was bonded with a titanium foil at 1400 °C for up to 1 h in Ar. The AlN/Ti interfacial reactions were investigated using analytical electron microscopy. Reaction layers, consisting of δ-TiN, τ2-Ti2AlN, γ-TiAl, α2-Ti3Al, a two-phase region (α2-Ti3Al + α-Ti), and α-Ti (Al, N) solid solution, were observed after annealing at 1400 °C for 0.1 h. Among these phases, the α2-Ti3Al and (α2-Ti3Al + α-Ti) were formed during cooling. Further diffusion of N atoms into the reaction zone precipitates a chopped fiber-like α2-Ti2AlN in the matrix of γ-TiAl, with [110]γ−TiAl//[11¯20]τ2−Ti2AlN and (1¯1¯1)γ−TiAl//(1¯10¯3)τ2−Ti2AlN, by substituting N atoms for one-half Al atoms after annealing at 1400 °C for 1 h. The released Al atoms, due to the precipitation of τ2-Ti2AlN, resulted in an ordered Al-rich γ-TiAl or Ti3Al5. Furthermore, the α-Ti (Al, N) was nitridized into a lamellar layer (δ-TiN + α-Ti) with [110]δ−TiN//[11¯20]α−Ti and (111)δ−TiN//(0001)α−Ti.
Low-temperature gas sensing in individual metal–oxide–metal heterojunction nanowires
Authors: Tresback Jason S. , Padture Nitin P.
Published: August 2008

CO-gas-sensing response of individual metal–oxide–metal (MOM) heterojunction nanowires (∼250 nm diameter) in the Au–NiO–Au system, where a nanoscale segment of NiO oxide (∼250 nm long) is sandwiched axially between Au nanowires, and between individual all-oxide NiO nanowires (∼250 nm diameter, ∼5 μm long), has been measured at 150 °C. While the all-oxide nanowires are highly resistive and show no measurable response, the MOM nanowires show ∼25% decrease in current with the introduction of 800 ppm CO. The response is reversible, but it is slow due to the low temperature used. MOM nanowires, by virtue of the nanoscale-dimension, low-resistance oxide segment and the high-quality “end-on” metal–oxide contact, are an attractive class of nanowire gas-sensing elements for potential use in multifunctional “bottom up” nanoelectronics.
Nucleation and early growth of anodized TiO2 film
Authors: Jaroenworaluck A. , Regonini D. , Bowen C.R. , Stevens R.
Published: August 2008

Anodized films of titanium were prepared under different controlled conditions in a water-based electrolyte containing fluorine ions, using either a constant potential or a potential gradually rising to 20 V. The films were then examined using transmission electron microscopy at different stages of growth, in particular, the very early stages of growth (30 s, 200 s, and 10 min) and when the ordered nano-tubular structure was finally established (2–4 h). The use of ramped voltage during the early stages of anodization allowed a well-interconnected porous network to develop and maintained active oxidation throughout anodization. The film, as formed, consisted mainly of amorphous oxide/hydroxides of titanium with small regions of nano-sized crystals. These were found more often in the denser regions of the amorphous network, particularly the arms of the coral-like structure that formed. As the anodized film grew in thickness, the pores tended to become aligned, leading to a surface layer of nanotubes on the electrode material. Electron optical characterization revealed that the nanotubes consist of a stack of rings where the passage of the current had been optimized.
Spherical indentation of a membrane on an elastic half-space
Authors: Kim Jae Hun , Gouldstone Andrew
Published: August 2008

A number of physiological systems involve contact or indentation of solids with tensed surface layers. In this paper the contact problem of spherical indentation of a linear elastic solid, covered with a tensed membrane is addressed. Semianalytical solutions are obtained relating indentation force to contact radius, as well as contact radius to depth. Good agreement is found between derived equations and results from finite element method (FEM) simulations. In addition, effect of membrane on subsurface stresses is shown quantitatively and compared favorably to FEM results. This work is applicable to mechanical property assessment of a number of biological systems.
Relationship between scratch hardness and yield strength of elastic perfectly plastic materials using finite element analysis
Authors: Lee Ki Myung , Yeo Chang-Dong , Polycarpou Andreas A.
Published: August 2008

With thin solid film usage expanding in numerous technologies, reliable measurements of material properties such as yield strength become important. However, for thin solid films the measurement of yield strength is not readily available, and an alternative method to obtain this property is to measure hardness and convert it to yield strength. Tabor suggested dividing hardness by ∼3 to obtain yield strength, which has been used extensively, despite its shortcomings. Since the pioneering work of Tabor, researchers have performed numerical and experimental studies to investigate the relationships between hardness, yield strength, and elastic modulus, using the indentation technique. In this study, finite element analysis was performed to simulate the nanoscratch technique. Specifically, the nanoscratch finite element analysis was used to validate a previously developed analytical scratch hardness model. A full-factorial design-of-experiments was performed to determine the significant variables for the ratio of calculated scratch hardness to yield strength and a simple analytical prediction model for the ratio of hardness to yield strength was proposed.
Allogeneic Injection of Fetal Membrane-Derived Mesenchymal Stem Cells Induces Therapeutic Angiogenesis in a Rat Model of Hind Limb Ischemia
Authors: Ishikane Shin , Ohnishi Shunsuke , Yamahara Kenichi , Sada Masaharu , Harada Kazuhiko , Mishima Kenichi , Iwasaki Katsunori , Fujiwara Michihiro , Kitamura Soichiro , Nagaya Noritoshi , Ikeda Tomoaki
Published: August 2008

Bone marrow-derived mesenchymal stem cells (BM-MSC) have been demonstrated to be an attractive therapeutic cell source for tissue regeneration and repair. However, it remains unknown whether or not allogeneic transplantation of mesenchymal stem cells (MSC) derived from fetal membranes (FM), which are generally discarded as medical waste after delivery, has therapeutic potential. FM-MSC were obtained from Lewis rats and had surface antigen expression and multipotent potential partly similar to those of BM-MSC. Compared with BM-MSC, FM-MSC secreted a comparable amount of hepatocyte growth factor despite a small amount of vascular endothelial growth factor. FM-MSC and BM-MSC both expressed major histocompatibility complex (MHC) class I but not MHC class II antigens and did not elicit allogeneic lymphocyte proliferation in mixed lymphocyte culture. FM-MSC or BM-MSC obtained from Lewis rats were injected into a MHC-mismatched August-Copenhagen-Irish rat model of hind limb ischemia. Three weeks after injection, blood perfusion and capillary density were significantly higher in the FM-MSC and BM-MSC groups than in the phosphate-buffered saline group, and allogeneic FM-MSC and BM-MSC were still observed. In nonischemic hind limb tissues, allogeneic FM-MSC and BM-MSC injection were associated with a comparatively small amount of T lymphocyte infiltration, compared with the injection of allogeneic splenic lymphocytes. In conclusion, allogeneic FM-MSC injection did not elicit a lymphocyte proliferative response and provided significant improvement in a rat model of hind limb ischemia, comparable to the response to BM-MSC. Thus, allogeneic injection of FM-MSC may be a new therapeutic strategy for the treatment of severe peripheral vascular disease.

Disclosure of potential conflicts of interest is found at the end of this article.
Regulatory Issues for Personalized Pluripotent Cells
Authors: Condic Maureen L. , Rao Mahendra
Published: August 2008

The development of personalized pluripotent stem cells for research and for possible therapies holds out great hope for patients. However, such cells will face significant technical and regulatory challenges before they can be used as therapeutic reagents. Here we consider two possible sources of personalized pluripotent stem cells: embryonic stem cells derived from nuclear transfer (NT-ESCs) and induced pluripotent stem cells (iPSCs) derived from direct reprogramming of adult somatic cells. Both sources of personalized pluripotent stem cells face unique regulatory hurdles that are in some ways significantly higher than those facing stem cells derived from embryos produced by fertilization (ESCs). However, the outstanding long-term potential of iPSCs and their relative freedom from the ethical concerns raised by both ESCs and NT-ESCs makes direct reprogramming an exceptionally promising approach to advancing research and providing therapies in the field of regenerative medicine.

Disclosure of potential conflicts of interest is found at the end of this article.
OP9 Stroma Augments Survival of Hematopoietic Precursors and Progenitors During Hematopoietic Differentiation from Human Embryonic Stem Cells
Authors: Ji Junfeng , Vijayaragavan Kausalia , Bosse Marc , Weisel Katja , Bhatia Mickie
Published: August 2008

The cellular mechanism and target cell affected by stromal microenvironments in augmenting hematopoietic specification from pluripotent human embryonic stem cells (hESCs) has yet to be evaluated. Here, in contrast to aorta-gonad-mesonephros-derived S62 stromal cells, OP9 cells inhibit apoptosis and also augment the proliferation of hemogenic precursors prospectively isolated from human embryoid bodies. In addition, OP9 stroma supported cells within the primitive hematopoietic compartment by inhibiting apoptosis of CD45+CD34+ cells committed to the hematopoietic lineage, but have no effect on more mature blood (CD45+CD34−) cells. Inability of hESC-derived hematopoietic cells cocultured with OP9 stromal cells to engraft in both the adult and newborn NOD/SCID mice after intrafemoral and intrahepatic injection illustrated that although OP9 stromal cells augment hESC-derived hematopoiesis and progenitor output, this optimized environment does not confer or augment repopulating function of specified hematopoietic cells derived from hESCs. OP9 coculture also increases hematopoietic progenitors output from hemogenic precursors overexpressing HOXB4. Our study demonstrates that OP9 cells support both hemogenic precursors and their primitive hematopoietic progeny, thereby providing the first evidence toward understanding the cellular targets and mechanisms underlying the capacity of OP9 stromal cells to support hematopoiesis from ESCs and define the future steps required to achieve the global goal of generating bona fide human hematopoietic stem cells from ESC lines.

Disclosure of potential conflicts of interest is found at the end of this article.
Behaviour of CFRP-strengthened slender square RC columns
Authors: Tao Z. , Yu Q.
Published: August 2008

The objective of this paper is to investigate the performance of slender square reinforced concrete (RC) columns strengthened with carbon fibre reinforced polymer (CFRP) jackets subjected to eccentric loading. Tests were conducted on eight RC columns strengthened with CFRP jackets, and another eight unstrengthened ones served as reference specimens. The main variables explored in this test programme include: (a) load eccentricity (0–150 mm); (b) with or without CFRP strengthening; and (c) CFRP configuration (unidirectional and bidirectional). Compared to those unstrengthened RC specimens, the test results showed that no obvious strength increase was observed for specimens confined by unidirectional CFRP jackets, while an increase of 22·8–61·8% was obtained for those strengthened by bidirectional CFRP jackets. The longitudinal fibres were effective in enhancing load-carrying capacity of slender RC columns subjected to eccentric loading.
Clinical Recommendations for Avoiding and Managing Surgical Complications Associated With Implant Dentistry: A Review
Authors: Greenstein Gary , Cavallaro John , Romanos George , Tarnow Dennis
Published: August 2008

Proposing to place endosseous implants is an integral facet of dental treatment plans. Their insertion is usually associated with a low incidence of untoward events. However, despite careful planning, surgical complications can arise: infection, intraoral hemorrhage, wound dehiscence, postoperative pain, lack of primary implant stability, inadvertent penetration into the maxillary sinus or nasal fossa, sinus lift sequelae, neurosensory disturbances, injuries to adjacent teeth, tissue emphysema, and aspiration, or ingestion of surgical instruments. This article addresses some surgical complications associated with dental implant placement and discusses how to avoid and manage them when they occur.
Changes in Gingival Dimensions Following Connective Tissue Grafts for Root Coverage: Comparison of Two Procedures
Authors: Han Jung S. , John Vanchit , Blanchard Steven B. , Kowolik Michael J. , Eckert George J.
Published: August 2008

Background: The purpose of this study was to investigate the changes in gingival dimensions and root coverage using the same surgical procedure but varying the amount of the connective tissue graft left uncovered.

Methods: Twenty‐five Class I or II recession defects in 20 healthy subjects were randomly assigned to test (exposed connective tissue group; E group) or control (fully covered connective tissue group; FC group) groups and treated with a connective tissue graft procedure. In the E group, 1 to 2 mm of the graft was left uncovered at the completion of the surgery, whereas the FC group had the graft completely covered by the flap. Clinical parameters assessed included probing depth, recession depth, clinical attachment level, width of keratinized tissue, mobility, and plaque score.

Results: At 12 weeks, the mean root coverage percentages for FC and E groups were 93% and 88%, respectively. The difference between the groups was not statistically significant (P = 0.48). Complete root coverage was observed in 79% and 64% of the subjects in FC and E groups, respectively. There was greater increase in the width of keratinized tissue in the E group (1.5 ± 1.1 mm) than the FC group (0.9 ± 0.9 mm), although this difference did not reach statistical significance (P = 0.16). There were no statistically significant differences between the groups for the changes in other parameters.

Conclusions: Both procedures resulted in successful root coverage with an increase in the width of keratinized tissue. Leaving a portion of the graft exposed resulted in a greater increase of keratinized tissue, and complete coverage of the graft resulted in greater root coverage. However, these differences did not reach statistical significance.
Long‐Term Results of Guided Tissue Regeneration Therapy With Non‐Resorbable and Bioabsorbable Barriers. IV. A Case Series of Infrabony Defects After 10 Years
Authors: Pretzl Bernadette , Kim Ti‐Sun , Holle Rolf , Eickholz Peter
Published: August 2008

Background: A 10‐year follow‐up study was conducted to clinically evaluate the long‐term results after guided tissue regeneration (GTR) therapy of infrabony defects using non‐resorbable and bioabsorbable barriers.

Methods: Twelve pairs of contralateral infrabony defects were treated in 12 subjects with advanced periodontitis. Within each subject, one defect received a non‐resorbable barrier and the other received a bioabsorbable barrier by random assignment. Clinical parameters were obtained at baseline and at 12 and 120 ± 6 months after surgery.

Results: Eight of 12 subjects were available for the examination at 120 ± 6 months. Twelve and 120 ± 6 months after GTR therapy statistically significant (P <0.05) vertical clinical attachment level (CAL‐V) gain was observed in both groups (3.4 ± 1.0 mm and 1.5 ± 1.2 mm for the control group at 12 and 120 months, respectively, and 3.3 ± 1.6 mm and 3.5 ± 2.5 mm for the test group at 12 and 120 months, respectively). However, 120 ± 6 months after GTR therapy, three infrabony defects (two controls and one test) had lost >2 mm of the attachment that had been gained 12 months after GTR therapy, and a statistically significant mean CAL‐V loss of 1.7 ± 1.3 mm was observed from 12 to 120 ± 6 months in the control group. One tooth in the control group was lost between 60 and 120 ± 6 months. The case series failed to show statistically significant differences between test and control regarding CAL‐V gain 120 ± 6 months after surgery.

Conclusion: CAL‐V gain achieved 12 months after GTR therapy in infrabony defects using non‐resorbable and bioabsorbable barriers was stable after 10 years in 12 of 16 defects.
Effect of Eucalyptus Extract Chewing Gum on Periodontal Health: A Double‐Masked, Randomized Trial
Authors: Nagata Hideki , Inagaki Yoshika , Tanaka Muneo , Ojima Miki , Kataoka Kosuke , Kuboniwa Masae , Nishida Nobuko , Shimizu Katsumasa , Osawa Kenji , Shizukuishi Satoshi
Published: August 2008

Background: Studies in vitro showed that eucalyptus extracts possess antibacterial activity against cariogenic and periodontopathic bacteria; however, the clinical effects with respect to periodontal health in humans remain unproven. The objective of this study was to evaluate the effect of chewing gum containing eucalyptus extract on periodontal health in a double‐masked, randomized, controlled trial.

Methods: Healthy humans with gingivitis but not deep periodontal pockets were randomly assigned to the following groups: high‐concentration group (n = 32): use of 0.6% eucalyptus extract chewing gum for 12 weeks (90 mg/day); low‐concentration group (n = 32): use of 0.4% eucalyptus extract chewing gum for 12 weeks (60 mg/day); and placebo group (n = 33): use of chewing gum without eucalyptus extract for 12 weeks. Plaque accumulation (PLA), gingival index (GI), bleeding on probing (BOP), periodontal probing depth (PD), and clinical attachment level (CAL) were measured at weeks 0, 4, 8, 12, and 14. Significance was analyzed with repeated‐measures two‐way analysis of variance followed by the Games‐Howell pairwise comparison test.

Results: The interaction between the effects of eucalyptus extract chewing gum and the intake period was statistically significant for PLA, GI, BOP, and PD but not for CAL. The low‐ and high‐concentration groups exhibited statistically significant (P <0.05) improvements compared to the placebo group for PLA, GI, BOP, and PD.

Conclusions: Eucalyptus extract chewing gum had a significant effect on PLA, GI, BOP, and PD. The use of eucalyptus extract chewing gum may promote periodontal health.
Interferon‐Gamma and Interleukin‐12 Gene Polymorphisms and Their Relation to Aggressive and Chronic Periodontitis and Key Periodontal Pathogens
Authors: Reichert Stefan , Machulla Helmut K.G. , Klapproth Jana , Zimmermann Uta , Reichert Yvonne , Gläser Christiane , Schaller Hans‐Günter , Schulz Susanne
Published: August 2008

Background: The gene polymorphisms interferon‐gamma (IFN‐γ) 874 T/A and interleukin (IL)‐12 1188 A/C have been associated with the altered production of cytokines. Therefore, they might be indicative of the occurrence of chronic periodontitis (CP) or aggressive periodontitis (AgP) and the prevalence of key periodontal pathogens. For this purpose, we analyzed these polymorphisms in subjects with generalized AgP or generalized CP. Moreover, we assessed the relationship between these polymorphisms and five periodontopathic bacteria.

Methods: A total of 124 unrelated German white subjects with periodontitis (AgP = 72 and CP = 52) and 74 periodontitis‐free subjects were studied. Gene polymorphisms were determined by polymerase chain reaction with sequence‐specific primers. Subgingival bacteria were molecular biologically analyzed using multiplex polymerase chain reaction and reverse hybridization. The distributions of alleles and genotypes were calculated by the χ2 test with Yates correction. Risk factor analyses were carried out by logistic regression considering established confounders for periodontitis.

Results: Allele and genotype frequencies of both investigated polymorphisms were not significantly different between subjects with periodontitis and periodontitis‐free controls. However, in the total study group, IL‐12 AA–positive subjects had a significantly higher bleeding index than individuals who expressed IL‐12 CC (68.2% versus 50.0%, P = 0.025). Moreover, IFN‐γ AA carriers had a decreased odds ratio (OR) for the individual presence of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) (OR = 0.39, P = 0.012) after adjustment for age, gender, smoking, and probing depth. IFN‐γ TA predisposed an individual to infection with Prevotella intermedia (OR = 2.15, P = 0.019).

Conclusion: Although a relationship between the bleeding index and the presence of bacteria was shown, IFN‐γ and IL‐12 polymorphisms are not suitable diagnostic features for AgP and CP.