bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetic Study of the Electroreduction of Benzoic Acid
Authors: Cheng Po-Chung , Nonaka Tsutomu
Published: July 2006

This work demonstrates the procedures needed to extract kinetic parameters from experimental data and to establish a reasonable model for the electroreduction of benzoic acid in a citrate buffer solution, a reaction typical of consecutive electrochemical reactions with solvent decomposition. Influences of operating conditions (current density, flow rate, etc.) on the formation ratio of benzaldehyde to benzyl alcohol were examined in a flow cell system with a lead cathode. Three reaction mechanism models taking into account dehydration and mass transfer of a hydrated benzaldehyde intermediate were discussed. Numerical calculations showed that the electrolyte in the vicinity of the cathode during an electrolysis was weakly alkaline. Factors controlling the product-selectivity of benzaldehyde are also discussed on the basis of simulation.
Highly Effective Dehydrogenation of Cyclohexanol to Cyclohexanone over Carbon-Supported Cobalt Catalyst
Authors: Uemichi Yoshio , Shouji Kiyoshi , Sugioka Masatoshi , Kanazuka Takaji
Published: July 2006

The dehydrogenation of cyclohexanol to cyclohexanone has been studied over activated carbon-supported transition metals as catalysts. The Co/carbon catalyst was found to be highly effective for the reaction. Its catalytic behaviors strongly depended on the temperature of hydrogen reduction. Highly dispersed and well-reduced cobalt catalyst showed pronounced activity and stability.
Factors Affecting the Redispersibility of Organosilica Sols Prepared by a Modification of Silica Particles with a Polyol-Based Polymer
Authors: Kito Taketoshi , Yamaye Makoto , Yoshinaga Kohji , Ishihara Youichi , Komatsu Michio , Nishida Hiroyasu
Published: July 2006

Organosilica sols which were redispersible in nonpolar or less polar organic solvents were prepared by a chemical modification of the silica surface with a polyol-based coupling polymer; the redispersibility was then examined in terms of the molecular weight of the coupling polymer, charged coupling polymer/silica (mmol g−1) (P/S) ratio, and the size of modified silica particles. Fractionated coupling polymers with an Mw/Mn of 2.0—2.8 were used. The charged P/S ratio was a leading factor for the redispersibility. The redispersibility was achieved when the charged P/S ratio exceeded approximately 0.3 mmol g−1, using coupling polymers of various molecular weights. The particle size of the modified silica decreased along with an increase in the charged P/S ratio and the reaction time. The presence of a free polymer was not essential for the redispersibility when the saturation of the silica surface with the coupling polymer was nearly completed.
Polymerization of 1-(1-Naphthyl)-1-propyne by Nb and Ta Catalysts and Polymer Properties: Effects of the 1-Naphthyl Group
Authors: Kouzai Hiroaki , Masuda Toshio , Higashimura Toshinobu
Published: July 2006

1-(1-Naphthyl)-1-propyne polymerized in the presence of NbCl5–cocatalyst systems to give virtually selectively a new polymer ca. 3 × 105) in high yields. Catalysts based on TaCl5 produced mixtures of the polymer and cyclotrimers. The polymer was a pale-yellow solid soluble in various organic solvents (e.g., toluene, CHCl3), and formed a free-standing film on solution casting. The onset temperature of the weight loss of the polymer in air was ca. 340 °C, which is higher than that (280 °C) of poly(1-phenyl-1-propyne) [poly(1-PP)]. The oxygen permeability coefficient at 25 °C was 80 barrers and one order of magnitude higher than that of poly(1-PP). These results are explicable in terms of the steric effects of the 1-naphthyl group.
Part I : Binary Oxide Catalysts of Alumina–Rare Earth Oxides
Authors: Jayasree Janakiamma , Narayanan Cadavallore S
Published: July 2006

Binary oxides of alumina with rare earths like europium, samarium, praseodymium, neodymium, and yttrium were prepared by coprecipitation from corresponding nitrates. The composition, thermal stability, and surface properties of the catalysts were determined using XRD, TGA, XPS, and MAS 27Al NMR. Surface area and pore size of the catalysts were determined by BET and mercury porosimetry. The catalysts were found to be amorphous and aluminium atom showed tetrahedral and octahedral coordination in its lattice. Catalysts showed weak to moderate acidity and basicity.
Part II: Transformations of α and β-Pinene Oxides over Binary Oxide Catalysts of Alumina–Rare Earth Oxides
Authors: Jayasree Janakiamma , Narayanan Cadavallore S
Published: July 2006

The catalytic activity of binary oxides of Al2O3–Eu2O3, Al2O3–Sm2O3, Al2O3–Nd2O3, Al2O3–Pr6O11, and Al2O3–Y2O3 were checked in the transformations of α and β-pinene oxides. Al2O3–Eu2O3 and Al2O3–Nd2O3 are found to be best catalysts for α-pinene oxide isomeriztion. Among the oxiranes, α-pinene oxide showed more activity mainly yielding 2,2,3-trimethyl cyclopentene-1-acetaldehyde. β-pinene oxide produced trans-myrtanal and myrtanol.
Stockout Compensation: Joint Inventory and Price Optimization in Electronic Retailing
Authors: Bhargava Hemant K. , Sun Daewon , Xu Susan H.
Published: June 2006

Delays in product availability are common in e-commerce where electronic retailers try to manage with very low inventories. While this lowers inventory costs, the negative effect of increased stockouts is to reduce net demand for the product. We analyze the effect of offering a lower price during stockout to compensate for a customer’s waiting time, using an EOQ-type inventory-modeling framework but solving simultaneously for both the optimal prices and the lengths of the in-stock and stockout periods. The lower price recaptures some lost demand and has an important synergistic effect: the increased sales rate leads to lower unit costs for inventory holding and product ordering. Stockout compensation improves market efficiency and increases the retailer’s sales and profit. The optimal stockout-compensation policy is to choose period lengths and prices such that the two periods have equal effective prices (i.e., the optimal stockout compensation equals the average waiting cost for a customer). Compared with the pure wait-free and stockless-operation policies, stockout compensation not only yields greater profits, but also greater revenues, lower unit costs, and increased consumer surplus and market coverage. Compared with a backorder policy without compensation, the stockout compensation policy improves profits and social welfare but at the expense of consumer surplus. Allowing for strategic consumer behavior under knowledge of future prices, the equal-effective-prices solution defines a rational-expectations equilibrium.
Optimal Synchronization Policies for Data Warehouses
Authors: Dey Debabrata , Zhang Zhongju , De Prabuddha
Published: June 2006

The notion of a data warehouse for integrating operational data into a single repository is rapidly becoming popular in modern organizations. An important issue in this context is how often one should synchronize the data warehouse to reflect the changes in the constituent operational data sources. If the synchronization is performed very frequently, the associated cost might be quite high, although the data warehouse would only have a small amount of stale data. On the other hand, if the data warehouse is synchronized infrequently, it might result in costly errors in business decisions arising from the stale data. This paper examines the trade-off between the synchronization and staleness costs and derives the optimal synchronization frequency.
Integrated Real-Time Capacity and Inventory Allocation for Reparable Service Parts in a Two-Echelon Supply System
Authors: Caggiano Kathryn E. , Muckstadt John A. , Rappold James A.
Published: July 2006

Two critical decisions must be made daily when managing multiechelon repair and distribution systems for service parts: (1) allocating available repair capacity among different items and (2) allocating available inventories to field stocking locations to support service operations. In many such systems, procurement lead times for service parts are lengthy and variable, repair capacity is limited, and operational requirements change frequently—resulting in demand processes that are highly uncertain and nonstationary. As a consequence, it is common to have many items in short supply while others are abundant. In such environments, integrated real-time decision-support tools can provide significant value by reducing the impact of inventory imbalances and responding appropriately to the volatile nature of the demand processes. By “integrated” and “real-time,” we mean (respectively) tools that simultaneously consider key aspects of the current state of the operating environment in deciding what items to repair, where to ship available units, and by what mode to ship them.

In this paper, we develop an integrated real-time model for making repair and inventory allocation decisions in a two-echelon reparable service parts system. We formulate the decision problem as a finite-horizon, periodic-review mathematical program, we show it can be formulated as a large-scale linear program, and we develop a practical heuristic method for solving the problem approximately. By simulating the operation of a service parts supply chain, we demonstrate the value of employing integrated decision models over using separate repair and inventory allocation rules for a range of environments where inventory imbalances exist. We also show that our heuristic approach is highly effective and that its inventory allocation subroutine, used as a stand-alone tool for making distribution decisions, outperforms a commonly used inventory allocation rule in most circumstances tested.
Immunofluorometric Point-of-Care Assays for the Detection of Acute Coronary Syndrome-Related Noncomplexed Pregnancy-Associated Plasma Protein A
Authors: Wittfooth Saara , Qin Qiu-Ping , Lund Juha , Tierala Ilkka , Pulkki Kari , Takalo Harri , Pettersson Kim
Published: June 2006

Background: We recently reported that the pregnancy-associated plasma protein A (PAPP-A) form specifically related to acute coronary syndromes (ACS) is not complexed with the proform of eosinophil major basic protein (proMBP). The aim of this study was to develop rapid point-of-care immunoassays for the measurement of the noncomplexed PAPP-A.

Methods: We developed immunofluorometric noncompetitive dry-reagent assays for total PAPP-A with 2 PAPP-A subunit-specific monoclonal antibodies and for PAPP-A/proMBP complex with 1 PAPP-A subunit-specific antibody and 1 proMBP subunit-specific antibody. The concentration of noncomplexed PAPP-A was determined as the difference of the results obtained with the 2 assays.

Results: The assays were linear from 0.5 to 300 mIU/L. The analytical detection limit and functional detection limit (CV <20%) were 0.18 mIU/L and 0.27 mIU/L for total PAPP-A assay and 0.23 mIU/L and 0.70 mIU/L for PAPP-A/proMBP assay, respectively. The total assay imprecisions were <10%, and recoveries were 88%–107% for both assays. The mean difference (95% limits of agreement) between the new total PAPP-A assay and a previously reported total PAPP-A assay was −3.2% (−45.7% to 39.3%; n = 546; P = 0.0019). In serum samples from 159 non-ACS individuals, median concentrations (interquartile range) were 2.42 (1.14) mIU/L for total PAPP-A, 2.20 (1.18) mIU/L for PAPP-A/proMBP, and 0.18 (0.63) mIU/L for noncomplexed PAPP-A. Total PAPP-A and PAPP-A/proMBP, but not noncomplexed PAPP-A, correlated with age (r = 0.290, P = 0.0002; r = 0.230, P = 0.0035; r = 0.075, P = 0.3483, respectively).

Conclusions: The new assays described revealed that noncomplexed PAPP-A is found only in negligible amounts in non-ACS samples.
Large Displays Enhance Optical Flow Cues and Narrow the Gender Gap in 3-D Virtual Navigation
Authors: Tan Desney S. , Czerwinski Mary P. , Robertson George G.
Published: June 2006

Objective: Existing reports suggest that males significantly outperform females in navigating 3-D virtual environments. Although researchers have recognized that this may be attributable to males and females possessing different spatial abilities, most work has attempted to reduce the gender gap by providing more training for females. In this paper, we explore using large displays to narrow the gender gap within these tasks. Background: While evaluating various interaction techniques, we found that large displays affording wider fields of view seemed to improve virtual navigation performance in general and, additionally, to narrow the gender gap that existed on standard desktop displays.Method: We conducted two experiments (32 and 22 participants) exploring the individual contributions of display and geometric fields of view to the observed effects as well as isolating factors explaining performance increases seen on the large displays. Results: We show that wider fields of view on large displays not only increase performance of all users on average but also benefit females to such a degree as to allow them to perform as well as males do. We further demonstrate that these benefits can be attributed to better optical flow cues offered by the large displays. Conclusion: These findings provide a significant contribution, including recommendations for the improved presentation of 3-D environments, backed by empirical data demonstrating performance benefits during navigation tasks. Application. Results can be used to design systems that narrow the gender gap in domains such as teleoperation and virtual environments for entertainment, virtual training, or information visualization.
Learning and Retention of Associations Between Auditory Icons and Denotative Referents: Implications for the Design of Auditory Warnings
Authors: Stephan Karen L. , Smith Sean E. , Martin Russell L. , Parker Simon P. A. , McAnally Ken I.
Published: June 2006

Objective: This study examined the way in which the type and preexisting strength of association between an auditory icon and a warning event affects the ease with which the icon/event pairing can be learned and retained. Background: To be effective, an auditory warning must be audible, identifiable, interpretable, and heeded. Warnings consisting of familiar environmental sounds, or auditory icons, have potential to facilitate identification and interpretation. The ease with which pairings between auditory icons and warning events can be learned and retained is likely to depend on the type and strength of the preexisting icon/event association. Method: Sixty-three participants each learned eight auditory-icon/denotative-referent pairings and attempted to recall them 4 weeks later. Three icon/denotative-referent association types (direct, related, and unrelated) were employed. Participants rated the strength of the association for each pairing on a 7-point scale. Results: The number of errors made while learning pairings was greater for unrelated than for either related or direct associations, whereas the number of errors made while attempting to recall pairings 4 weeks later was greater for unrelated than for related associations and for related than for direct associations. Irrespective of association type, both learning and retention performance remained at very high levels, provided the strength of the association was rated greater than 5. Conclusion: This suggests that strong preexisting associations are used to facilitate learning and retention of icon/denotative-referent pairings. Application: The practical implication of this study is that auditory icons having either direct or strong, indirect associations with warning events should be preferred.
Presence and Quality of Navigational Landmarks: Effect on Driver Performance and Implications for Design
Authors: May Andrew J. , Ross Tracy
Published: June 2006

Objective: The objective of this study was to investigate the impact of landmark information of varying quality within drivers' navigation instructions on driving and navigation performance when navigating an unfamiliar route. Background: Current vehicle navigation systems predominantly use distance-to-turn information to enable a driver to locate a forthcoming maneuver. Although it has been proposed that the design of driver navigation aids can be improved through the incorporation of landmarks as key navigation cues, little research has investigated how the quality of the landmark affects driver behavior. Method: An empirical field trial in a real traffic environment was undertaken with 48 participants in order to assess the effect of landmark quality on driver behavior when navigating an unfamiliar, complex, urban route. Results: The use of good landmarks (as opposed to poor landmarks or distance information) as key verbal navigation cues resulted in significant improvements in navigation performance, driving performance, and driver confidence immediately preceding a turn. The use of distance information to locate a turn resulted in significantly more glances to the in-vehicle display. Conclusions: Good landmarks offer significant safety and performance benefits to a driver navigating an unfamiliar route. Poor landmarks can result in driver performance worse than that obtained using distance to turn to locate forthcoming maneuvers. Application: The design of future vehicle navigation systems should not rely on distance-to turn information alone to enable a driver to locate forthcoming maneuvers but, rather, should incorporate good landmarks within the navigation instructions they present to drivers.
A Comparison of the Cell Phone Driver and the Drunk Driver
Authors: Strayer David L. , Drews Frank A. , Crouch Dennis J.
Published: June 2006

Objective: The objective of this research was to determine the relative impairment associated with conversing on a cellular telephone while driving. Background: Epidemiological evidence suggests that the relative risk of being in a traffic accident while using a cell phone is similar to the hazard associated with driving with a blood alcohol level at the legal limit. The purpose of this research was to provide a direct comparison of the driving performance of a cell phone driver and a drunk driver in a controlled laboratory setting. Method: We used a high-fidelity driving simulator to compare the performance of cell phone drivers with drivers who were intoxicated from ethanol (i.e., blood alcohol concentration at 0.08% weight/volume). Results: When drivers were conversing on either a handheld or hands-free cell phone, their braking reactions were delayed and they were involved in more traffic accidents than when they were not conversing on a cell phone. By contrast, when drivers were intoxicated from ethanol they exhibited a more aggressive driving style, following closer to the vehicle immediately in front of them and applying more force while braking. Conclusion: When driving conditions and time on task were controlled for, the impairments associated with using a cell phone while driving can be as profound as those associated with driving while drunk. Application: This research may help to provide guidance for regulation addressing driver distraction caused by cell phone conversations.
Navigation Performance With a Virtual Auditory Display: Effects of Beacon Sound, Capture Radius, and Practice
Authors: Walker Bruce N. , Lindsay Jeffrey
Published: June 2006

Objective: We examined whether spatialized nonspeech beacons could guide navigation and how sound timbre, waypoint capture radius, and practice affect performance. Background: Auditory displays may assist mobility and wayfinding for those with temporary or permanent visual impairment, but they remain understudied. Previous systems have used speech-based interfaces. Method: Participants (108 undergraduates) navigated three maps, guided by one of three beacons (pink noise, sonar ping, or 1000-Hz pure tone) spatialized by a virtual reality engine. Dependent measures were efficiency of time and path length. Results: Overall navigation was very successful, with significant effects of practice and capture radius, and interactions with beacon sound. Overshooting and subsequent hunting for waypoints was exacerbated for small radius conditions. A human-scale capture radius (1.5 m) and sonar-like beacon yielded the optimal combination for safety and efficiency. Conclusion: The selection of beacon sound and capture radius depend on the specific application, including whether speed of travel or adherence to path are of primary concern. Extended use affects sound preferences and quickly leads to improvements in both speed and accuracy. Application: These findings should lead to improved wayfinding systems for the visually impaired as well as for first responders (e.g., firefighters) and soldiers.
Large-scale gene expression studies of the endometrium: what have we learnt?
Authors: Sherwin Rob , Catalano Rob , Sharkey Andrew
Published: July 2006

The endometrium is a dynamic tissue that undergoes coordinated changes under the influence of steroid hormones. This results in proliferation and differentiation culminating in a receptive state, followed by menstruation and endometrial repair. These functions involve complex interactions between the epithelium, stroma and leucocytes in the endometrium. Understanding the underlying causes of endometrial disorders, such as infertility, endometriosis and heavy menstrual bleeding, therefore represents a considerable challenge. Recently developed techniques, such as differential display and DNA microarrays permit the abundance of thousands of mRNA transcripts within cells or tissues to be measured simultaneously. This provides a new approach to understanding the complex interactions that underlie both healthy and disease states. Responses of the endometrium to hormones or drugs can be studied and the response of the system as an integrated whole can be assessed. Comparisons of endometrium from healthy women and those with endometrial dysfunction have advanced our understanding of key areas of endometrial physiology, including infertility, receptivity, endometriosis and cancer. Using this approach, novel genes controlling specific endometrial functions like receptivity have been identified for functional testing. This paper will review the impact of these techniques for transcript profiling on our understanding of selected areas of endometrial biology and discuss the potential applications in future.
Formation of ovarian follicular fluid may be due to the osmotic potential of large glycosaminoglycans and proteoglycans
Authors: Clarke Hannah G , Hope Sarah A , Byers Sharon , Rodgers Raymond J
Published: July 2006

During mammalian follicle development, a fluid-filled antrum develops in the avascular centre of the follicle. We investigated the hypothesis that follicular fluid contains osmotically-active molecules, sufficiently large so as to not freely escape the follicular fluid. Such molecules could generate an osmotic differential and thus recruit fluid from the surrounding vascularised stroma into the antrum. Follicular fluid was collected from bovine follicles classified histologically as healthy (n = 4 pools) or atretic (n = 4 pools). Dialysis of the follicular fluid at 300 kDa or 500 kDa resulted in a reduction in colloid osmotic pressure of 35% and 60%, respectively, in fluid from healthy follicles and 29% and 80% from atretic follicles. Digestion of follicular fluid with Streptomyces hyaluronidase, chondroitinase ABC or DNase 1 followed by dialysis resulted in reductions in osmotic pressure of 43%, 53% and 43% respectively for fluids from healthy follicles and 34%, 20% and 31% for atretic follicles. Digestion with collagenase I, proteinase K, heparanase 1 or keratanase had no significant effect on the osmotic pressure of follicular fluid of healthy follicles. Ion exchange and size exclusion, Western blotting and ELISA identified the proteoglycans versican and inter-alpha trypsin inhibitor and the glycosaminoglycan hyaluronan in follicular fluid. We conclude that these molecules or aggregates of them are of sufficient size to contribute to the osmotic potential of follicular fluid and thus recruit fluid into the follicular antrum. DNA may also contribute but it is probably not a component that is regulated for this role.
Differential glucocorticoid effects on proliferation and invasion of human trophoblast cell lines
Authors: Mandl M , Ghaffari-Tabrizi N , Haas J , Nöhammer G , Desoye G
Published: July 2006

Several clinical situations require continuous glucocorticoid (GC) treatment during pregnancy. A well-known deleterious side effect of such treatment is the higher incidence of growth-restricted fetuses, for which a too shallow trophoblast invasion is presently hypothesised as the underlying cause. This study investigated whether the synthetic GC triamcinolone acetonide (TA) influences proliferation, invasion and endocrine activity of human trophoblast. BeWo and JEG-3 choriocarcinoma cell lines both express GC receptors (western blotting) and were used as models for human trophoblast. JAR devoid cells of GC receptor were used as negative control. The cells were cultured for 48 h without (control) or with 0.5, 5 and 50 μM TA. In the presence and absence of serum, proliferation was determined by cell counting and measuring the cell cycle regulating protein cyclin B1 (Western blotting); invasion was determined by a conventional Matrigel invasion assay and by measuring the secretion (ELISA) of matrix-metalloproteinases (MMP-2, MMP-9) into the culture medium; endocrine activity was assessed by measuring the levels of human chorionic gonadotropin (ELISA) into the culture medium. TA altered the number of viable and dead cells as well as cyclin B1 levels and, to a lesser extent, invasion of BeWo and JEG-3, with a strong influence of serum. BeWo and JEG-3 cells reacted differently and in most instances reverse. In the cell lines used as models of human trophoblast, TA alter some functions relevant to proliferation and invasion, and suggest that caution should be exercised when treating women with GCs during pregnancy.
Microarray technology offers a novel tool for the diagnosis and identification of therapeutic targets for male infertility
Authors: He Zuping , Chan Wai-Yee , Dym Martin
Published: July 2006

Male infertility is now a major reproductive health problem because of an increasing number of environmental pollutants and chemicals, which eventually result in gene mutations. Genetic alterations caused by environmental factors account for a significant percentage of male infertility. Microarray technology is a powerful tool capable of measuring simultaneously the expression of thousands of genes expressed in a single sample. Eventually, advances in genetic technology will allow for the diagnosis of patients with male infertility due to congenital reasons or environmental factors. Since its introduction in 1994, microarray technology has made significant advances in the identification and characterization of novel or known genes possibly correlated with male infertility in mice, as well as in humans. This provides a rational basis for the application of microarray to establishing molecular signatures for the diagnosis and gene therapy targets of male infertility. In this review, the differential gene expression patterns characterized by microarray in germ and somatic cells at different steps of development or in response to stimuli, as well as a number of novel or known genes identified to be associated with male infertility in mice and humans, are addressed. Moreover, issues pertaining to measurement reproducibility are highlighted for the application of microarray data to male infertility.
Seminal plasma regulates ovarian progesterone production, leukocyte recruitment and follicular cell responses in the pig
Authors: O’Leary S , Jasper M J , Robertson S A , Armstrong D T
Published: July 2006

Seminal plasma (SP) acts to influence the uterine endometrium after mating, activating synthesis of embryotrophic cytokines and inflammatory changes that condition the tract for embryo implantation and establishing pregnancy. The objective of this study was to investigate in pigs whether the ovary might also be responsive to SP exposure. Prepubertal gilts were synchronised with exogenous gonadotrophins and received transcervical treatment with pooled boar SP or PBS; then the ovarian tissue was recovered at 34 h (preovulation) and on days 5 and 9 after treatment. The ovarian response was assessed by measuring ovulation rate, number and size of corpora lutea, ovarian leukocyte populations, progesterone production in vivo, as well as responses of retrieved granulosa cells cultured in vitro. In SP-treated gilts, leukocyte recruitment into the ovarian tissues was increased fourfold at 34 h, with macrophages comprising the most abundant cell lineage. There was no effect of SP on the number of oocytes ovulated; however, the weight of corpora lutea was increased in SP-treated gilts. SP also induced an increase in plasma progesterone content seen from day 5 to at least day 9 after treatment. In addition, granulosa cells and thecal tissue retrieved from preovulatory follicles of SP-treated gilts were more responsive in vitro to growth factor- and gonadotrophin-stimulated cell proliferation and progesterone synthesis. These results suggest that uterine exposure to SP influences immune cell trafficking in the ovary and enhances steroidogenesis in early pregnancy. The effects of SP on ovarian function potentially contribute to reproductive success in the pig.
Luteinization of porcine preovulatory follicles leads to systematic changes in follicular gene expression
Authors: Agca Cansu , Ries James E , Kolath Sarah J , Kim Jae-Hwan , Forrester Lawrence J , Antoniou Eric , Whitworth Kristin M , Mathialagan Nagappan , Springer Gordon K , Prather Randall S , Lucy Matthew C
Published: July 2006

The LH surge initiates the luteinization of preovulatory follicles and causes hormonal and structural changes that ultimately lead to ovulation and the formation of corpora lutea. The objective of the study was to examine gene expression in ovarian follicles (n = 11) collected from pigs (Sus scrofa domestica) approaching estrus (estrogenic preovulatory follicle; n = 6 follicles from two sows) and in ovarian follicles collected from pigs on the second day of estrus (preovulatory follicles that were luteinized but had not ovulated; n = 5 follicles from two sows). The follicular status within each follicle was confirmed by follicular fluid analyses of estradiol and progesterone ratios. Microarrays were made from expressed sequence tags that were isolated from cDNA libraries of porcine ovary. Gene expression was measured by hybridization of fluorescently labeled cDNA (preovulatory estrogenic or -luteinized) to the microarray. Microarray analyses detected 107 and 43 genes whose expression was decreased or increased (respectively) during the transition from preovulatory estrogenic to -luteinized (P<0.01). Cells within preovulatory estrogenic follicles had a gene-expression profile of proliferative and metabolically active cells that were responding to oxidative stress. Cells within preovulatory luteinized follicles had a gene-expression profile of nonproliferative and migratory cells with angiogenic properties. Approximately, 40% of the discovered genes had unknown function.
Topical Voriconazole Solution for Cutaneous Aspergillosis in a Pediatric Patient After Bone Marrow Transplant
Authors: Klein Kristin C. , Blackwood R. Alexander
Published: July 2006

Invasive aspergillosis seems to be on the rise, especially in immunocompromised children. Historically, only systemic amphotericin B has been effective against Aspergillus. Development of newer antifungal agents, such as voriconazole and caspofungin, has improved the treatment options available for aspergillosis, although no definitive management strategy has been established. Here we describe the use of topical voriconazole combined with systemic antifungal agents for cutaneous aspergillosis in a pediatric patient after bone marrow transplant.
Successful Parental Use of an Automated External Defibrillator for an Infant With Long-QT Syndrome
Authors: Divekar Abhay , Soni Reeni
Published: July 2006

Congenital long-QT syndrome with 2:1 atrioventricular block presenting in the perinatal period is rare, has a poor prognosis, and leads to high risk for lethal ventricular arrhythmic events. An implantable cardioverter-defibrillator seems to be the most effective treatment in the prevention of arrhythmic sudden cardiac death in patients with long-QT syndrome. Technical limitations and risks associated with implantable cardioverter-defibrillators in asymptomatic infants is considered too great to justify use for primary prophylaxis against sudden cardiac death. In this case report we describe the first successful parental use of an automated external defibrillator prescribed for primary prophylaxis against sudden cardiac death in an infant with long-QT syndrome.
Comparison of diffraction methods for measurement of surface damage in superalloys
Authors: Brewer L.N. , Othon M.A. , Gao Y. , Hazel B.T. , Buttrill W.H. , Zhong Zhong
Published: June 2006

Surface damage from machining operations is a potential source of failure in metallic components. The ability to quantitatively characterize the depth and extent of the damage layer is critical to controlling the machining process. Electron back scattered diffraction and synchrotron high energy x-ray diffraction were applied to the measurement of machining surface damage in a Ni-based super alloy. Both techniques clearly showed a plastic deformation profile below the surface as a function of the machining conditions used. Using the average intragrain misorientation parameter, the electron back scattered diffraction was able to quantify the amount of surface damage from one surface treatment to another. In addition, the x-ray diffraction measurements were able to simultaneously measure the elastic strain as a function of depth from the surface.
Interfacial reactions in the Sn–20 at.% In/Cu and Sn–20 at.% In/Ni couples at 160 °C
Authors: Lin Shih-kang , Chen Sinn-wen
Published: June 2006

Sn–In alloys are promising low-melting-point Pb-free solders. Cu and Ni are common substrates in the electronic products. This study examines the interfacial reactions in the Sn–20 at.% In(γ–InSn4)/Cu and Sn–20 at.% In/Ni couples at 160 °C. Only the η–Cu6Sn5 phase layer is formed in the Sn–20 at.% In/Cu couple, and the layer grows thicker with longer reaction time. The reaction path is γ–InSn4/η–Cu6Sn5/Cu. A peculiar phenomenon with the bulging of the couple near the Ni substrate is found in the Sn–20 at.% In/Ni couple. A liquid phase is formed by interfacial reaction in the solid/solid Sn–20 at.% In/Ni couple at 160 °C, and the reaction path is γ–InSn4/liquid/δ–Ni3Sn4 + liquid/(δ–Ni3Sn4)/Ni. Usually Ni has a slower reaction rate with solders; however, the consumption rates of Ni substrate are much higher than those of Cu substrate in this study when they are in contact with the Sn–20 at.% In alloy at 160 °C due to the formation of the liquid phase in the Sn–20 at.% In/Ni couple.
TiO-based coatings prepared by plasma spraying in air of Ti + C mixtures
Authors: Haller B. , Grimaud A. , Labbe J-C. , Bonnet J-P.
Published: June 2006

This work presents an original way for preparing TiO-based coatings by thermal spraying. As titanium monoxide is oxidized by the mere trace of oxygen contained in hydrogen, it is obvious that plasma spraying of TiO powder does not lead easily to the formation of a titanium monoxide coating. However, thermodynamical calculations show that the conditions necessary for the preparation of TiO can be reached, at the titanium melting temperature (Tm=1933 K), when oxygen reacts with liquid metal in the presence of excess carbon. These results have led to experiments in which TiO-based coatings have been prepared by spraying a stoichiometric mixture of graphite and titanium grains onto cast iron in air. In optimal conditions, a gas-tight hard coating (1000 ± 15 HV3) of a TiO-based phase (composition: TiO0.81±0.06C0.04±0.02) has been obtained.
Physical properties of porous titania films composed of nanoparticle aggregates
Authors: Ogunsola Oluwatosin , Park Jinwon , Lee Gil , Ehrman Sheryl
Published: June 2006

Highly porous films of titania composed of nanoparticle aggregates were synthesized via gas-to-particle conversion and particle-precipitated chemical vapor deposition. The films were annealed in air for 12 h at temperatures ranging from 400 to 1000 °C. Atomic force microscopy was used to determine the Young's modulus and hardness of both the as-synthesized and annealed films. The Young's modulus and hardness of the as-synthesized films were 4.0 ± 0.4 MPa and 0.026 ± 0.003 MPa, respectively. There was no significant change in either modulus or hardness upon annealing until the films were annealed at a temperature of 1000 °C. The Young's modulus and hardness of these films were 56 ± 6 MPa and 0.10 ± 0.01 MPa, respectively. Results from dynamic light scattering measurements of aggregate size and surface area measurements suggest that annealing at 1000 °C leads to increased networking between distinct nanometer-scale titania aggregates, which strengthens the film.
Effects of ball-milling conditions and additives on the hydrogen sorption properties of Mg + 5 wt% Cr2O3 mixtures
Authors: Bobet J-L. , Kandavel M. , Ramaprabhu S.
Published: June 2006

Effects of particle size of Cr2O3 catalyst on the hydrogen absorption/desorption kinetics of Mg + 5 wt% Cr2O3 mixtures have been studied. To explain the effect of particle size of Cr2O3 and also to yield information about the role of Cr2O3 during the sorption process, the kinetics data have been analyzed using Avrami–Erofeev rate equations. The activation energies and diffusion coefficients of these mixtures are in the ranges of 50.6–63.2 kJ/mol and 1.2.10−11 to 8.9.10−10 cm2/s, respectively. The addition of nano-oxides led to an increase of the diffusion coefficient of hydrogen by one order of magnitude.
Bulk nanocrystalline stainless steel fabricated by equal channel angular pressing
Authors: Huang C.X. , Gao Y.L. , Yang G. , Wu S.D. , Li G.Y. , Li S.X.
Published: June 2006

Bulk fully nanocrystalline grain structures were successfully obtained in ultralow carbon stainless steel by means of equal channel angular pressing at room temperature. Transmission electron microscopy (TEM) and high-resolution TEM investigations indicated that two types of nanostructures were formed: nanocrystalline strain-induced martensite (body-centered cubic structure) with a mean grain size of 74 nm and nanocrystalline austenite (face-centered cubic structure) with a size of 31 nm characterized by dense deformation twins. The results about the formation of fully nanocrystalline grain structures in stainless steel suggested that a low stacking fault energy is exceptionally profitable for producing nanocrystalline materials by equal channel angular pressing.
Nanometric oxides from molecular precursors in the presence of starch: Coatings of glass with these oxides in silica sols
Authors: Callone Emanuela , Carturan Giovanni , Ischia Marco , Sicurelli Adriana
Published: June 2006

Sn, Sn-Sb, Ti, Ce, Zr, Zn, In, In–Sn, and Fe oxides of nanometric size were obtained through the hydrolytic route, starting from molecular precursors in the presence of starch. Gels were treated with α-amylase to produce oxide suspensions and starch degradation. Solid oxide products resulted from reaction with H2O2, washing with H2O, and centrifugation of the suspensions. The nanometric size and morphology of crystallites were assessed by x-ray diffractometry, transmission electron microscopy, and, for SnO2, solid-state nuclear magnetic resonance. Product consolidation at 600 °C did not produce any noticeable increase in dimensions. Thermal analysis coupled with mass spectrometry of evolved gaseous species showed that glucoside residues remain chemically bonded to the nanoparticles, thus explaining the effective stabilization of crystallite dimensions. Aqueous suspensions of nanopowders were mixed with a silicon tetra-ethoxide ethanol solution and subjected to an ordinary sol-gel process. The resulting suspensions were used to obtain stable and homogeneous coatings on glass sheets.
Plasma-assisted metalorganic chemical vapor deposition growth of ZnO thin films
Authors: Losurdo Maria , Giangregorio Maria M. , Sacchetti A. , Capezzuto Pio , Bruno Giovanni , Malandrino Graziella , Fragalà Ignazio L.
Published: June 2006

ZnO thin films have been grown by metalorganic chemical vapor deposition (MOCVD) and plasma-assisted (PA) MOCVD on c-axis-oriented sapphire (0001) and Si (001) substrates using the novel Zn(2-thenoyltrifluoroacetonate)2·N,N,N′,N′-tetramethylethylendiamine precursor. The structural, morphological, and optical properties of ZnO films have been investigated. The results show that the O2 PA growth results in highly c-axis-oriented hexagonal ZnO thin films also on cubic substrates. PA-MOCVD ZnO films have good optical properties, as inferred by the presence of a sharp and intense exciton in the dielectric function.
Kinetic mechanism of TiO2 nanocarving via reaction with hydrogen gas
Authors: Yoo Sehoon , Dregia Suliman A. , Akbar Sheikh A. , Rick Helene , Sandhage Kenneth H.
Published: June 2006

Dense polycrystalline titania (TiO2, rutile) was converted into oriented arrays of single-crystal titania nanofibers by reaction with a noncombustible, hydrogen-bearing gas mixture at only 680–780 °C. Such nanofiber formation resulted from anisotropic etching (“nanocarving”) of the titania grains. The fibers possessed diameters of 20–50 nm and lengths of up to several microns, with the long fiber axes oriented parallel to the [001] crystallographic direction of rutile. Mass spectroscopy and inductively coupled plasma spectroscopy indicated that oxygen, but not titanium, was removed from the specimen during the reaction with hydrogen. The removal of substantial oxygen and solid volume from the reacting surfaces, without an appreciable change in the Ti:O ratio at such surfaces, was consistent with the solid-state diffusion of titanium cations from the surface into the bulk of the specimen. The reaction-induced weight loss followed a parabolic rate law, which was also consistent with a solid-state diffusion-controlled process.
Effective grain alignment in bismuth titanate ceramic by centrifugal force
Authors: Xiang Ping-Hua , Kinemuchi Yoshiaki , Watari Koji , Ishiguro Hirohide , Cao Fei , Dong Xian-Lin
Published: June 2006

Effective grain alignment in bismuth titanate ceramic was successfully realized by a novel pressure sintering technology, centrifugal sintering, in which centrifugal force is introduced by high-speed rotation of materials during the process of sintering. X-ray diffraction analyses indicated a very high orientation degree with a Lotgering factor f of ∼0.96 in centrifugal sintered samples. Scanning electron micrographs revealed that the platelike grains are well oriented with their c axes parallel to centrifugal force. The mechanism responsible for grain alignment with introduction of centrifugal force was tentatively proposed.
Field-assisted synthesis of BaTiO3 particle/polyvinylbutyral composite film
Authors: Kondo Yusuke , Shimura Tetsuo , Sakamoto Wataru , Yogo Toshinobu
Published: June 2006

BaTiO3 particle/polyvinylbutyral composite films were synthesized from titanium-organics and barium ions in aqueous solution using a direct current (dc) field. Titanium-organic films on stainless substrates were reacted with barium nitrate solution under dc field. BaTiO3 nanoparticles were formed in the precursor film at temperatures as low as 30 °C at atmospheric pressure. The crystallization of BaTiO3 particles was dependent on the synthetic conditions, such as applied field, reaction time, and temperature. Crystalline BaTiO3 particles were synthesized in the polymer matrix at 2.3 V/cm and 50 °C for 2 h. The absorption edge of BaTiO3 particle/polyvinylbutyral composite was 343 nm and was blue-shifted compared with that of micron-sized BaTiO3.
Conductivity relaxation in the interfacial phase of iron core–iron oxide shell nanocomposites
Authors: Basu S. , Macdonald J.R. , Chakravorty D.
Published: June 2006

The alternating current electrical conductivity of a gel-derived glass of composition 55Fe2O3⋅45SiO2 (mol%) was measured over a frequency range of 100 Hz to 6 MHz. The gel was subjected to a reduction treatment at 923 K for ½ h and subsequently heated in ordinary atmosphere at a temperature 773 K for ½ h to grow a Fe-core Fe3O4 shell nanostructure with a median diameter of 6.2 nm. This formed a percolative network within the silica gel. Mossbauer spectra confirmed the presence of Fe3O4 in the nanoshell. Electrical measurements were also carried out on these nanocomposites at different frequencies and temperatures. Isothermal electrical modulus data for both reference and treated glass systems were analyzed using both the CK0 and CK1 Kohlrausch-related frequency response models. Reference-glass shape parameter values, estimated by fitting the experimental data to the K0 model at several temperatures, were found to be ∼0.32. Here, the K0 model led to much better fits than the K1 did. However, for the treated core–shell-structured nanocomposite material, both models yielded good fits with consistent but different shape parameter estimates: very close to ½ for the K0 model and ⅓ for the K1 model. In accordance with the structural measurements and with axiomatic topological considerations that predict a shape-parameter value of ⅓ for one-dimensional motion and ½ for two-dimensional motion, it appears that the ∼0.32 value is consistent with one-dimensional motion of charge carriers along the narrow channels of the interconnected iron-rich three-dimensional phase of the reference glass. Further, although the K1-model ⅓ estimates for the treated material also indicate the presence of one-dimensional charge motion at the two-dimensional interface between the two interconnected phases of the reference glass, the ½ K0 estimates for the same material suggest an effective charge-motion dimension of 2. Importantly, comparison of the high-frequency dielectric constant estimates for the K0 reference glass and the K1 treated one clearly leads to the new but physically plausible conclusion that the bulk frequency-independent dielectric constant of about 30 is independent of the treatment.
Preparation and characterization of a novel solid solution of aluminum in tungsten carbide by mechanically activated high-temperature reaction
Authors: Yan Junmin , Ma Xianfeng , Zhao Wei , Tang Huaguo , Zhu Changjun , Cai Shuguang
Published: June 2006

In this work, a novel substitutional solid solution (W0.8Al0.2)C was synthesized by mechanically activated high-temperature reaction. X-ray diffraction was used for phase identification during the whole reaction process. Environment scanning electronic microscopy–field emission gun and energy dispersive x-ray were used to investigate the microstructure and the quantitative material composition of the specimen. (W0.8Al0.2)C was found to crystallize in the WC-type, and the cell parameters were a = 2.907(1) Å and c = 2.837(1) Å. The hardness of (W0.8Al0.2)C was tested to be 19.3 ± 1 GPa, and the density was 13.19 ± 0.05 g cm−3.
Polarization and phase of light transmitted through polymer‐dispersed liquid‐crystal film
Authors: Loiko Valery A. , Konkolovich Alexander V. , Maksimenko Polina G.
Published: July 2006

Abstract— A method for calculating the transmission coefficient, phase shift, and characteristics of the polarization state of light, transmitted through a PDLC film with nanosized nematic droplets, is considered. Functional dependences of these values on the morphological characteristics of a film are obtained and graphically illustrated. Good agreement between the theoretical and available experimental data is established.