bluuebunny/crossref_metadata_2025 huggingface dataset:
Pediatric Traumatic Brain Injury Is Inconsistently Regionalized in the United States
Authors: Hartman Mary , Watson Robert Scott , Linde-Zwirble Walter , Clermont Gilles , Lave Judith , Weissfeld Lisa , Kochanek Patrick , Angus Derek
Published: July 2008

OBJECTIVES. Traumatic brain injury is a leading cause of death in children. On the basis of evidence of better outcomes, the American College of Surgery Committee on Trauma recommends that children with severe traumatic brain injury receive care at high-level trauma centers. We assessed rates of adherence to these recommendations and factors associated with adherence.

METHODS. We studied population and hospital discharge data from 2001 from all of the health care referral regions (n = 68) in 6 US states (Florida, Massachusetts, New Jersey, New York, Texas, and Virginia). We identified children with severe traumatic brain injury by using International Classification of Diseases, Ninth Revision, Clinical Modification, codes and American College of Surgery Committee on Trauma criteria. We defined “high-level centers” as either level I or pediatric trauma centers. We considered an area to be well regionalized if ≥90% of severe traumatic brain injury hospitalizations were in high-level centers. We also explored how use of level II trauma centers affected rates of care at high-level centers.

RESULTS. Of 2117 admissions for severe pediatric traumatic brain injury, 67.3% were in high-level centers, and 87.3% were in either high-level or level II centers. Among states, 56.4% to 93.6% of severe traumatic brain injury admissions were in high-level centers. Only 2 states, Massachusetts and Virginia, were well regionalized. Across health care referral regions, 0% to 100% of severe traumatic brain injury admissions were in high-level centers, and only 19.1% of health care referral regions were well regionalized. Only a weak relationship existed between the distance to the nearest high-level center and regionalization. The age of statewide trauma systems had no relationship to the extent of regionalization.

CONCLUSIONS. Despite evidence for improved outcomes of severely injured children admitted to high-level trauma centers, we found that almost one third of the children with severe traumatic brain injury failed to receive care in such centers. Only 2 of 6 states and less than one fifth of 68 health care referral regions were well regionalized. This study highlights problems with current pediatric trauma care that can serve as a basis for additional research and health care policy.
Clinical and Genetic Analysis of Unclassifiable Inherited Bone Marrow Failure Syndromes
Authors: Teo Juliana T. , Klaassen Robert , Fernandez Conrad V. , Yanofsky Rochelle , Wu John , Champagne Josette , Silva Mariana , Lipton Jeffrey H. , Brossard Jossee , Samson Yvan , Abish Sharon , Steele MacGregor , Ali Kaiser , Athale Uma , Jardine Lawrence , Hand John P. , Tsangaris Elena , Odame Isaac , Beyene Joseph , Dror Yigal
Published: July 2008

OBJECTIVE. Unclassified inherited bone marrow failure syndromes are a heterogeneous group of genetic disorders that represent either new syndromes or atypical clinical courses of known inherited bone marrow failure syndromes. The relative prevalence of the unclassified inherited bone marrow failure syndromes and their characteristics and the clinical and economic challenges that they create have never been studied.

METHODS. We analyzed cases of inherited bone marrow failure syndrome in the Canadian Inherited Marrow Failure Registry that were deemed unclassifiable at study entry.

RESULTS. From October 2001 to March 2006, 39 of the 162 patients enrolled in the Canadian Inherited Marrow Failure Registry were registered as having unclassified inherited bone marrow failure syndromes. These patients presented at a significantly older age (median: 9 months) than the patients with classified inherited bone marrow failure syndrome (median: 1 month) and had substantial variation in the clinical presentations. The hematologic phenotype, however, was similar to the classified inherited bone marrow failure syndromes and included single- or multiple-lineage cytopenia, severe aplastic anemia, myelodysplasia, and malignancy. Grouping patients according to the affected blood cell lineage(s) and to the presence of associated physical malformations was not always sufficient to characterize a condition, because affected members from several families fit into different phenotypic groups. Compared with the classified inherited bone marrow failure syndromes, the patients with unclassified inherited bone marrow failure syndromes had 3.2 more specific diagnostic tests at 4.5 times higher cost per evaluated patient to attempt to categorize their syndrome. At last follow-up, only 20% of the unclassified inherited bone marrow failure syndromes were ultimately diagnosed with a specific syndrome on the basis of the development of new clinical findings or positive genetic tests.

CONCLUSIONS. Unclassified inherited bone marrow failure syndromes are relatively common among the inherited bone marrow failure syndromes and present a major diagnostic and therapeutic dilemma.
Newborn Vitamin A Supplementation Reduced Infant Mortality in Rural Bangladesh
Authors: Klemm Rolf D.W. , Labrique Alain B. , Christian Parul , Rashid Mahbubur , Shamim Abu Ahmed , Katz Joanne , Sommer Alfred , West Keith P.
Published: July 2008

OBJECTIVES. We assessed the effect of supplementing newborns with 50000 IU of vitamin A on all-cause infant mortality through 24 weeks of age.

PATIENTS AND METHODS. This was a community-based, double-masked, cluster-randomized, placebo-controlled trial conducted in 19 unions in rural northwest Bangladesh. The study was nested into and balanced across treatment arms of an ongoing placebo-controlled, weekly maternal vitamin A or β-carotene supplementation trial. Study-defined sectors (N = 596) were evenly randomized for newborns of participating mothers to receive a single, oral supplement of vitamin A (50000 IU) or placebo as droplets of oil squeezed from a gelatinous capsule. Mothers provided informed consent for newborn participation at ∼28 weeks' gestation. After birth, typically at home (where >90% of births occurred), infants were supplemented and their vital status was followed through 24 weeks of age. The main outcome measure was mortality through 24 weeks of age.

RESULTS. We obtained maternal consent to dose 17116 live-born infants (99.8% of all eligible) among whom 15937 (93.1%) were visited to be supplemented <30 days after birth and for whom vital status at 24 weeks of age was known. Dosed infants (n = 15902 [99.8%]) received their study supplement at a median age of 7 hours. Relative to control subjects, the risk of death in vitamin A–supplemented infants was 0.85, reflecting a 15% reduction in all-cause mortality. Protective relative risks were indistinguishable by infant gender, gestational age, birth weight, age at dosing, maternal age, parity, or across the 3 treatment arms of the maternal supplementation trial.

CONCLUSIONS. Newborn vitamin A dosing improved infant survival through the first 6 months of life in Bangladesh. These results corroborate previous findings from studies in Indonesia and India and provide additional evidence that vitamin A supplementation shortly after birth can reduce infant mortality in South Asia.
Asthma Prevalence Among US Children in Underrepresented Minority Populations: American Indian/Alaska Native, Chinese, Filipino, and Asian Indian
Authors: Brim Susan N. , Rudd Rose A. , Funk Renee H. , Callahan David B.
Published: July 2008

OBJECTIVES. The purpose of this work was to estimate asthma prevalence among US children in racial minority subgroups who have been historically underrepresented in the pediatric asthma literature. These subgroups include American Indian/Alaska Native, Chinese, Filipino, and Asian Indian children. We also explored the association between these race categories and asthma after adjusting for demographic and sociodemographic characteristics and explored the effect of place of birth as it relates to current asthma.

PATIENTS AND METHODS. Data on all 51944 children aged 2 to 17 years from the 2001–2005 National Health Interview Survey were aggregated and analyzed to estimate the prevalence of current asthma, lifetime asthma, and asthma attacks according to race and place of birth. Logistic regression was used to determine adjusted odds ratios for current asthma according to race and place of birth while controlling for other demographic and sociodemographic variables.

RESULTS. National estimates of current asthma prevalence among the children in the selected minority subgroups ranged from 4.4% in Asian Indian children to 13.0% in American Indian/Alaska Native children. Overall, children born in the United States had greater adjusted odds of reporting current asthma than did children born outside of the United States.

CONCLUSIONS. Smaller racial and ethnic minority groups are often excluded from asthma studies. This study reveals that, among children from different Asian American subgroups, wide variation may occur in asthma prevalence. We also found that children born in the United States were more likely than children born outside of the United States to have current asthma.
Young Adults With Very Low Birth Weight: Leaving the Parental Home and Sexual Relationships—Helsinki Study of Very Low Birth Weight Adults
Authors: Kajantie Eero , Hovi Petteri , Räikkönen Katri , Pesonen Anu-Katriina , Heinonen Kati , Järvenpää Anna-Liisa , Eriksson Johan G , Strang-Karlsson Sonja , Andersson Sture
Published: July 2008

OBJECTIVE. Although most children and adults who are born very preterm live healthy lives, they have, on average, lower cognitive scores, more internalizing behaviors, and deficits in social skills. This could well affect their transition to adulthood. We studied the tempo of first leaving the parental home and starting cohabitation with an intimate partner and sexual experience of young adults with very low birth weight (<1500 g).

METHODS. In conjunction with the Helsinki Study of Very Low Birth Weight Adults, 162 very low birth weight individuals and 188 individuals who were born at term (mean age: 22.3 years [range: 18.5–27.1]) and did not have any major disability filled out a questionnaire. For analysis of their ages at events which had not occurred in all subjects, we used survival analysis (Cox regression), adjusted for gender, current height, parents' ages at the birth, maternal smoking during pregnancy, parental educational attainment, number of siblings, and parental divorce/death.

RESULTS. During their late teens and early adulthood, these very low birth weight adults were less likely to leave the parental home and to start cohabiting with an intimate partner. In gender-stratified analyses, these hazard ratios were similar between genders, but the latter was statistically significant for women only. These very low birth weight adults were also less likely to experience sexual intercourse. This relationship was statistically significant for women but not for men; however, very low birth weight women and men both reported a smaller lifetime number of sex partners than did control subjects.

CONCLUSIONS. Healthy young adults with very low birth weight show a delay in leaving the parental home and starting sexual activity and partnerships.
Dynamic force microscopy study of the microstructural evolution of pulsed laser deposited ultrathin Ni and Ag films
Authors: Kumar Prashant , Krishna M. Ghanashyam , Bhatnagar A.K. , Bhattacharya A.K.
Published: July 2008

Ultrathin films (6–10 nm) of silver and nickel were deposited by pulsed laser deposition (PLD) in high vacuum (1 × 10−6 mbar). Microstructural evolution of these films as function of incident laser energy, substrate temperature, substrate material [borosilicate glass, fused silica, MgO(100) and Si (311)] and target–substrate distance was studied in detail using dynamic force microscopy. It is shown that with increase in laser energy incident on the target, there is a substantial increase in particle size in the film. The effect of increased laser energy on microstructure is much more drastic than that for the increase of substrate temperature. In general, denser packing of nanoparticles and increased clustering have been observed at elevated substrate temperature. Increase in laser energy gives rise to higher average grain size, packing density, and clustering in comparison to substrate temperature. It is observed that the aspect ratio of grains is dependent on incident laser fluence and substrate temperature, but more drastically on the substrate material. Substrate coverage and aspect ratio of the grains are particularly dependent on the nature of crystallinity of the substrates. It is demonstrated that PLD provides a greater degree of microstructural manipulation than other physical vapor deposition techniques.
In situ formation process and mechanism of bulk MgB2 before Mg melting
Authors: Shi Qing-Zhi , Liu Yong-Chang , Gao Zhi-Ming , Zhao Qian , Ma Zong-Qing
Published: July 2008

Differential thermal analysis, as the main means of measurement, was used to prepare bulk MgB2 samples and monitor the sintering reaction process. Combined with microstructure observation by scanning electron microscopy and x-ray diffraction analysis, the formation process of MgB2 phase at the temperature before Mg melting was summarized. Additionally, a new kinetic analysis (a variant on the Flynn–Wall–Ozawa) method under nonisothermal conditions was used to determine that the reaction between Mg and B powders involves random nucleation followed by an instantaneous growth of nuclei (Avrami–Erofeev equation, n = 2), which can properly explain the in situ formation process of bulk MgB2 at the temperature before Mg melting. The value of activation energy E and the function of conversion f(α) are obtained independently, and thereby the determination of mechanism function is not affected by the value of E. The values of E decrease from 175.418 to 160.395 kJ mol−1 with the increase of the conversion degrees (α) from 0.1 to 0.8. However, as the conversion degrees approach 0.9, the value of E increases to 222.647 kJ mol−1, and the corresponding pre-exponential factor A is about three orders of magnitude larger than the previous ones.
Berkovich indentation of diamondlike carbon coatings on silicon substrates
Authors: Haq Ayesha J. , Munroe P.R. , Hoffman M. , Martin P.J. , Bendavid A.
Published: July 2008

The deformation behavior of diamondlike carbon (DLC) coatings on silicon substrates induced by Berkovich indentation has been investigated. DLC coatings deposited by a plasma-assisted chemical vapor deposition technique were subjected to nanoindentation with a Berkovich indenter over a range of maximum loads from 100 to 300 mN. Distinct pop-ins were observed for loads greater than 150 mN. However, no pop-out was observed for the loads studied. The top surface of the indents showed annular cracks with associated fragmented material. The cross sections showed up to 20% localized reduction in thickness of the DLC coating beneath the indenter tip. Cracking, {111} slip, stacking faults, and localized phase transformations were observed in the silicon substrate. The discontinuities in the load–displacement curves at low loads are attributed to plastic deformation of the silicon substrate, whereas at higher loads they are attributed to plastic deformation as well as phase transformation.
Engineering aerosol-through-plasma torch ceramic particulate structures: Influence of precursor composition
Authors: Phillips Jonathan , Luhrs Claudia , Peng Chunyun , Fanson Paul , Zea Hugo
Published: July 2008

This is the second in a series of articles demonstrating the unique character of the aerosol-through-plasma (A-T-P) process for producing nanoparticles. This study is focused on the impact of two parameters, cation ratio (1:3, 1:1, 3:1) and solvent (evaporated prior to generation of aerosol), on the structures of Ce:Al oxides particles. These two simple changes were found to impact virtually every aspect of particle structure, including the fraction of hollow versus solid, fraction of nanoparticles, phase structure, and even the existence of surface phase segregation. CeAl mixed oxides were found only over a limited range of compositions, and that range was a function of the solvent. At all other cation ratios, only ceria was a crystalline phase, and most if not all the alumina is amorphous. It is notable that the fraction of hollow micron-sized particles and nanoparticles is greatly influenced by the cation ratio and solvent identity. Indeed, significant numbers of nanoparticles were only produced using an aqueous precursor with a Ce:Al ratio of 1:1. Another unique finding is that phase segregation exists in individual particles on the length scale of nanometers. This study compliments an earlier study of the influence of operating conditions on particle structure. Taken together, the studies suggest a means to engineer (as well as limits to the engineering possibilities) ceramic particle structures using the A-T-P method.
Microstructure and properties of pressureless sintered ZrC-based materials
Authors: Silvestroni Laura , Sciti Diletta
Published: July 2008

ZrC-based composites were produced by pressureless sintering thanks to the addition of MoSi2 as sintering aid. After preliminary tests, a baseline ZrC material and two mixed ZrC–HfC and ZrC–ZrB2 composites with 20 vol% MoSi2 were densified at 1900 to 1950 °C reaching final relative densities of 96%–98%. Mean particle size of the dense bodies ranged from 5 to 9 μm. Secondary phases were found to form during sintering, such as SiC and Zr–Mo–Si-based compounds. Room-temperature mechanical properties were in the range of the values reported in the literature for similar materials densified by pressure-assisted techniques. The flexural strength was tested at room temperature, 1200 and 1500 °C.
Solid/solid interfacial reactions between Sn–0.7 wt% Cu and Ni–7 wt% V
Authors: Chen Chih-chi , Chen Sinn-wen , Chang Chih-horng
Published: July 2008

Sn–0.7 wt% Cu alloy is an important Pb-free solder, and Ni–7 wt% V is the major diffusion barrier layer material of flip chip technology. Reactions at the Sn–0.7 wt% Cu/Ni–7 wt% V interface are examined at 160, 180, and 210 °C. Only the Cu6Sn5 phase is formed in the Sn–0.7 wt% Cu/Ni–7 wt% V couple reacted at 160 and 180 °C; however, in addition to the Cu6Sn5 and Ni3Sn4 phases, a quaternary Q phase is formed in the Sn–0.7 wt% Cu/Ni–7 wt% V couple reacted at 210 °C. The Q phase is a mixture of nanocrystalline Ni3Sn4 phase and an amorphous phase. With longer reaction time at 210 °C in the Ni–V/Q/Sn–Cu couple where the Q phase is in direct contact with solder, the Ni3Sn4 phase nucleates inside the preformed Q phase, and the alternating layer phenomenon Ni–V/Q/Ni3Sn4/Q/Ni3Sn4/Cu6Sn5/Sn–Cu is observed. The interesting solid state amorphization and alternating layer phenomena at 210 °C are primarily caused by the fact that Sn and Cu are fast diffusing species, while V is relatively immobile.
Thermochemistry of nanoparticles on a substrate: Zinc oxide on amorphous silica
Authors: Shvareva Tatiana Y. , Ushakov Sergey V. , Navrotsky Alexandra , Libera Joseph A. , Elam Jeffrey W.
Published: July 2008

Crystalline samples of zinc oxide on a mesoporous amorphous silica substrate were prepared by 5 to 15 atomic layer deposition cycles with diethyl zinc and water at 150 °C. Samples were characterized by x-ray diffraction, thermogravimetry, and nitrogen adsorption–desorption isotherms. High-temperature oxide melt solution calorimetry and water adsorption calorimetry experiments were performed to measure surface enthalpy for crystalline ZnO particles supported on the substrate. The measured enthalpies 1.23 ± 0.35 and 2.07 ± 0.59 J/m2 for hydrous and anhydrous surfaces, respectively, are in agreement with previously reported measurements for unsupported ZnO nanoparticles. Feasibility of thermochemical characterization of complex system of atomic layer deposition (ALD) prepared particles on a substrate was demonstrated.
Enhanced ripening behavior of Mg-doped CdSe quantum dots
Authors: Sung Yun-Mo , Kwak Woo-Chul , Kim Woong , Kim Tae Geun
Published: July 2008

Pure CdSe and Mg-doped CdSe nanocrystal quantum dots were synthesized into the zinc-blende structure at a low temperature by the inverse micelle technique using paraffin oil and oleic acid as surface capping agents. The ripening behavior of the nanocrystals was monitored using the red shift in ultraviolet (UV)-visible light absorption peaks, and their size variation was estimated using the so-called, quantum confinement theory. The Lifshitz–Slyozov–Wagner (LSW) kinetics analyses were performed based on the variation in size according to the ripening temperature and time period. The activation energy (Q) and reaction rate constant (Ko) were determined for the ripening reaction using Arrhenius-type plots. The kinetics analyses reveal that the volume diffusion through the liquid-phase solution is the governing mechanism for the ripening of both nanocrystals. The Mg-doped CdSe nanocrystals showed enhanced ripening kinetics due to the low activation energy for the volume diffusion.
In situ mechanical observations during nanoindentation inside a high-resolution scanning electron microscope
Authors: Rzepiejewska-Malyska K.A. , Buerki G. , Michler J. , Major R.C. , Cyrankowski E. , Asif S.A.S. , Warren O.L.
Published: July 2008

In nanoindentation, the occurrence of cracks, pileup, sink-in, or film delamination adds additional complexity to the analysis of the load–displacement curves. Many techniques and analysis methods have been used to extract both qualitative and quantitative information from the indentation test both during and after the test. Much of this information is obtained indirectly or may even be overlooked by current testing methods (e.g., cracks that open only during the loading cycle of the test may go unnoticed from a typical residual indentation analysis). Here we report on the development of a miniature depth-sensing nanoindentation instrument and its integration into a high-resolution scanning electron microscope. Real-time observation of the nanoindentation test via scanning electron microscopy allows for visualization and detection of certain events such as crack initiation, pileup, or sink-in, and other material deformation phenomena. Initial results from aluminum 〈100〉 and a thin gold film (∼225 nm) are presented.
Characterization of biofunctional thin films deposited by activated vapor silanization
Authors: Arroyo-Hernández María , Pérez-Rigueiro José , Conde Ana , Climent Aurelio , Gago Raul , Manso Miguel , Martínez-Duart José M.
Published: July 2008

A novel technique based in the combination of vapor silanization and chemical vapor deposition, hereafter referred to as activated vapor silanization (AVS), is shown to be an effective biofunctionalization technique. The AVS process results in thin organic films with a high surface amine concentration when deposited on substrates with different chemical characteristics, such as silicon, porous silicon, or gold. Chemical characterization shows that the films are composed of carbon (hydrocarbon, C–Si, C–C), silicon (different oxidation states), nitrogen (primary and secondary amines), oxygen, and hydrogen. Relevantly, the amines are also distributed along the film thickness, ensuring functionality even after some degradation of the films. AVS films behave practically as monocrystalline silicon substrates under loading–unloading tests. In addition, the AVS films behave as permeable membranes for molecules smaller than 5 Å, and the amine surface concentration is estimated to be 8 NH2/nm2 for molecules of about 12 Å, which is three times higher than that obtained with standard silanization procedures.
Formation and compression mechanical properties of Ni–Zr–Nb–Pd bulk metallic glasses
Authors: Qiang J.B. , Zhang W. , Inoue A.
Published: July 2008

The formation of bulk metallic glasses (BMGs) and their room temperature mechanical properties have been investigated in a serial of Ni65−xZr20Nb15Pdx (x = 0∼15; at.%) quaternary alloys, which are hopefully hydrogen-permeation materials. The partial substitution of Ni with Pd in Ni65Zr20Nb15 alloy has proved to be effective in improving glass-forming ability (GFA) and thermal stability. In particular, good BMG-forming compositions were revealed within the Pd content range of 2.5–12.5 at.%, and BMG rods of 3 mm in diameter were successfully made at compositions Ni57.5Zr20Nb15Pd7.5 and Ni55Zr20Nb15Pd10 by copper mold casting. The addition of Pd enhanced the thermal stability of the supercooled liquid. With an increase of Pd content, the supercooled liquid span, ΔTx = Tx − Tg, increased from 29 K at Ni65Zr20Nb15 to 47 K at Ni52.5Zr20Nb15Pd12.5. The Pd-bearing BMGs exhibited high fracture strength, which ranged from 2750 to 2850 MPa. These Pd-bearing BMGs showed a certain degree of toughness, and the highest plastic strain, about 2%, was reached in the Ni60Zr20Nb15Pd5 BMG.
Low-temperature one-step synthesis of covalently chelated ZnO/dopamine hybrid nanoparticles and their optical properties
Authors: Huang WeiMin , Jiang Peng , Wei ChenYang , Zhuang DaKui , Shi Jianlin
Published: July 2008

Dopamine covalently chelated ZnO nanoparticles were synthesized by a nonaqueous one-step chemical process at a temperature as low as 60 °C. The formation of ZnO/dopamine hybrid structure was proved by x-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) techniques. Detailed absorption, luminescence, and time-resolved decay studies were performed for these ZnO/dopamine hybrid nanoparticles. We observed an enhanced green emission, which could be assigned to a new band-gap emission based on the fast of nanosecond lifetime of the green emission. Our results demonstrated that the change of optical properties of ZnO nanoparticles after covalently chelated by dopamine ligands is closely associated with the formation of new band structure.
Synthesis and formation mechanism of hollow carbon spheres encapsulating magnetite nanocrystals
Authors: Liu Boyang , Jia Dechang , Feng Haibo , Meng Qingchang , Shao Yingfeng
Published: July 2008

Hollow carbon spheres encapsulating magnetite nanocrystals were obtained in high-pressure argon at 600 °C followed by hydrolysis of Fe(NH3)2Cl2 in the hollow interiors at room temperature and heat treatment in argon at 450 °C for 2 h. The structure, morphology, and properties of the products were characterized by x-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and vibrating sample magnetometry. The hollow carbon spheres have diameters of 1–10 μm and wall thicknesses of hundreds of nanometers; the wt% of magnetite nanocrystals in them is ∼13.2%. Equiaxed magnetite nanocrystals range in size from 15 to 90 nm, while acicular magnetite nanocrystals have diameters of ∼20 nm and lengths of 120–450 nm. The saturation magnetization value of the hollow carbon spheres encapsulating magnetite nanocrystals is 4.29 emu/g.
Role of minor addition of metallic alloying elements in formation and properties of Cu–Ti-rich bulk metallic glasses
Authors: Park E.S. , Chang H.J. , Kyeong J.S. , Kim D.H.
Published: July 2008

The effect of minor addition (MA) of metallic alloying elements in Cu–Ti-rich Cu–Ti–Zr–Ni–Si bulk metallic glasses (BMGs) has been investigated. MA of elements having a relatively small positive enthalpy of mixing (partial substitution of Zr with Nb) leads to enhancement of compressive plasticity (up to about 5% of fracture strain) when the addition leads to improvement in glass-forming ability (GFA). If the GFA is reduced (partial substitution of Ni with Ag or Co), the plasticity is also reduced. On the one hand, the MA of elements having a relatively large positive enthalpy of mixing (partial substitution of Zr with Y) can lead to the liquid-state phase separation in Cu–Ti–Zr–Ni–Si(–Sn) BMGs, although the addition can lead to drastic deterioration in GFA and plasticity. This concept would be considered to be effective even in design of other BMG systems with tailored properties.
Effects of HfO2 buffer layer thickness on the properties of Pt/SrBi2Ta2O9/HfO2/Si structure
Authors: Leu Ching-Chich , Lin Chen-Han , Chien Chao-Hsin , Yang Ming-Jui
Published: July 2008

We investigated structural and characteristic changes in thin HfO2 films (<10 nm) by varying their thicknesses and also examined their influence on the properties of Pt/SrBi2Ta2O9/HfO2/Si metal/ferroelectric/insulator/semiconductor (MFIS) structures. HfO2 films with different thicknesses were found to exhibit rather distinct characteristics and to profoundly affect the properties of the fabricated MFIS capacitor. We found that, when employing 3.2-nm-thick HfO2 as the buffer layer, the MFIS capacitor showed good memory performance at low operation voltage. However, this study demonstrated that some of the HfO2 limited its application in MFIS memory, even though it is the most promising alternative gate dielectric material.
Multicolor luminescence in oxygen-deficient Tb3+-doped calcium aluminogermanate glasses
Authors: Lin Geng , Zhu Bin , Zhou Shifeng , Yang Hucheng , Qiu Jianrong
Published: July 2008

In this paper, we report on the multicolor luminescence in oxygen-deficient Tb3+-doped calcium aluminogermanate glasses. A simple method was proposed to control oxygen-deficient defects in glasses by adding metal Al instead of the corresponding oxide (Al2O3), resulting in efficient blue and red emissions from Tb3+-undoped glasses with 300 and 380 nm excitation wavelengths, respectively. Moreover, in Tb3+-doped oxygen-deficient glasses, bright three-color (sky-blue, green or yellow, and red) luminescence was observed with 300, 380, and 395 nm excitation wavelengths, respectively. These glasses are useful for the fabrication of white light-emitting diode (LED) lighting.
Grain growth and void formation in dielectric-encapsulated Cu thin films
Authors: Yao B. , Sun T. , Kumar V. , Barmak K. , Coffey K.R.
Published: July 2008

Grain growth in 40-nm-thick Cu films encapsulated by over- and under-layers of SiO2, Al2O3, Si3N4, and MgO was investigated. The films were magnetron sputter deposited onto cooled SiO2/Si substrates in an ultrahigh vacuum purity environment. Ex situ annealing was performed at 400 and 800 °C in 1 atm reducing gas. Films deposited at −120 °C exhibited more extensive grain growth after annealing than films deposited at −40 °C. Films annealed at room temperature had grain sizes less than 35 nm. All films exhibited some void formation after annealing at 400 and 800 °C, but the films encapsulated in Al2O3 exhibited the lowest area fraction of voids. The mean grain sizes of the Al2O3-encapsulated films, as measured by the linear intercept method, were 86 and 134 nm after annealing at 400 and 800 °C, respectively.
Factors Affecting Seed Germination and Emergence of Venice Mallow (Hibiscus trionum)
Authors: Chachalis Demosthenis , Korres Nikolaos , Khah Embrahim M.
Published: July 2008

Venice mallow is an emerging weed problem in many regions of the world in various crops. Studies on its hard seed coat were conducted by scanning electron, light, and fluorescence microscopy. The effects of environmental factors on germination and seedling emergence were examined in laboratory experiments. Seeds possessed physical dormancy (90%) that required immersion for 0.5 h in concentrated sulfuric acid to break without damaging the seed. After scarification, 29% of seeds exhibited primary embryo dormancy. Exposure of seeds to even short periods of 15 d of prechilling induced secondary dormancy (10% germination). The surface of hard seeds had a velvety appearance from numerous papillate structures and deposits (hydrophilic material). The location of the water barrier was very superficial in the outer seed coat. Although, in hard seeds, the hilar area appeared to have vertical ruptures and the hilum fissure appeared to be open, there was no water entry. It was observed that microruptures could be the region of structural weakness of hard seeds in relation to water permeability during prolonged burial (8 mo).

The highest (60%) germination was recorded at a day/night temperature of 30/20 C with a 12-h photoperiod. No germination was measured at either 10 or 45 C constant temperature. Germination was recorded with a broad range of pH (3-11) and seeds were rather tolerant to low water potential (20% germination at –1.2 MPa). Seedling emergence was higher for seeds buried at 2 cm than for those placed on the surface (54 vs. 38%, respectively). These results showed that Venice mallow is a rather unique species that possesses a complex mechanism of dormancy (physical, primary, and secondary). Information gained in this study will be used in developing management strategies for this species.
Effect of Branched Broomrape (Orobanche ramosa) Infection on the Growth and Photosynthesis of Tomato
Authors: Mauromicale Giovanni , Monaco Antonino Lo , Longo Angela M. G.
Published: July 2008

The influence of the holoparasite branched broomrape on the vegetative growth, leaf chlorophyll content, photosynthetic rate, and chlorophyll fluorescence of tomato was studied over two growing seasons on plants grown in a commercial greenhouse. The presence of the parasite strongly reduced the aerial biomass by acting as a competing sink for assimilate, but more importantly, by compromising the efficiency of carbon assimilation via a reduction in leaf chlorophyll content and photosynthetic rate. The chlorophyll fluorescence parameters F0, Fm, Fv, and Fv/Fm were all altered in parasitized plants, indicating that branched broomrape–infected plants are more susceptible to photoinhibition. The degree of damage to the host was not dependent on either the number or the biomass of parasitic plants per host plant. We suggest that the ability to maintain a high photosynthetic rate, leaf chlorophyll content, or both and the ability to minimize photoinhibition can be developed as indirect assays for improved tolerance to branched broomrape.
Amino Acid Substitutions in the Acetolactate Synthase Gene of Red Rice (Oryza sativa) Confer Resistance to Imazethapyr
Authors: Sales Marites A. , Shivrain Vinod K. , Burgos Nilda R. , Kuk Yong I.
Published: July 2008

Two red rice accessions from Arkansas have been found to be resistant to the labeled rate of imazethapyr, which is used to control red rice in ClearfieldTMrice. Full-length amplification of the acetolactate synthase (ALS) gene in imazethapyr-resistant red rice revealed a coding sequence of 1,935 base pairs, which is the same as that of the cultivated rice. Coding sequences were generated from four red rice accessions collected from different geographical regions in Arkansas, consisting of accessions that were either resistant or susceptible to imazethapyr. Nucleotide sequence alignments identified six base polymorphisms, three of which resulted in amino acid substitutions in theALSgene. One amino acid substitution, Gly654Glu, involves a residue required for imazethapyr binding to the ALS. The other substitution, Val669Met, implies conformational changes in the ALS structure that enhances binding of thiamine diphosphate, an ALS cofactor. These novel amino acid substitutions first reported for ALS-resistant red rice accessions support the hypothesis that ALS-resistant red rice can evolve with sustained herbicide selection pressure. Thus, it behooves growers to integrate the Cleafield rice technology with other tools to achieve a successful, long-term weed management program.
Growth Regulators and Chemicals Stimulate Germination of Leafy Spurge (Euphorbia esula) Seeds
Authors: Foley Michael E. , Chao Wun S.
Published: July 2008

Baseline information on inducing germination of dormant leafy spurge seeds with growth regulators and chemicals is lacking. This study was conducted to survey the effect of various substances on germination of leafy spurge seeds. The nontreated control seeds in this population were nearly fully imbibed in 3 h and displayed approximately 35% germination in 21 d under the normal alternating temperature of 20/30 C (16/8 h). Gibberellic acid (GA3, 10 mM) induced 65% germination at constant temperatures of 20 and 30 C. The alternating temperature increased the effectiveness of 10 mM GA3with 94% germination, a twofold increase over the control. Nontreated seeds did not germinate at the constant temperatures, suggesting that alternating temperature acts via a GA-independent pathway. Kinetin at 0.1 to 1 mM was no more effective than the control, but a saturated solution of kinetin induced 73% germination. Ethephon at 0.01 to 1 mM induced 58 to 66% germination, although there was little response to different concentrations. Ethylene gas at 1 ppm stimulated germination to 77%, a 1.8-fold increase over the control. Germination of seeds incubated continuously in 1 and 10 mM nitrate displayed 35 and 40% germination, respectively. Seeds pulsed for 24 h with 100 mM nitrate displayed 58% germination after 21 d. Potassium phosphate–citrate buffer (pH 3.4) and its individual components induced 60 to 70% germination. Fluridone (10 and 100 µM), 1-naphthaleneacetic acid (NAA, 0.1 to 10 mM), and ethanol (0.2 to 15%) had no effect on germination, but subsequent elongation in the presence of NAA was inhibited because of swelling of the radicle. This research reveals that GA3is the most effective growth regulator for germination of dormant leafy spurge seeds, and its effect is independent of temperature.
Purple Nutsedge (Cyperus rotundus) Management in an Organic Production System
Authors: Bangarwa Sanjeev K. , Norsworthy Jason K. , Jha Prashant , Malik Mayank
Published: July 2008

Research was initiated in March 2005 to test various integrated purple nutsedge management strategies over two growing seasons in an organic production system in which bell pepper was grown as a fall crop. Main plots consisted of integrated purple nutsedge management strategies from mid-March through July 2005 and 2006. The main-plot factors were (1) green polyethylene film, (2) clear polyethylene film, (3) turnip followed by (fb) green polyethylene film, (4) turnip fb clear polyethylene film, (5) tillage every 3 wk, and (6) fallow. Subplots consisted of hand-weeding, mulching with wheat straw, and no weeding following bell pepper transplanting in early August. Purple nutsedge tuber density was determined in March, August, and November each year. Viable tubers were categorized into three sizes: small (0.1 to 0.25 g), medium (0.26 to 0.50 g), and large (> 0.50 g). The initial tuber density averaged 500 small, 300 medium, and 110 large tubers m−2in mid-March 2005 (910 total tubers m−2). Total tuber density increased to > 5,400 tubers m−2in fallow, nonweeded plots by November 2006. Yearly tuber density remained relatively constant over the 2 yr when the fallow period was fb hand-weeding in the bell pepper crop. Density of large and medium tubers in the season-long management systems remained stable, whereas small tubers were prone to depletion over time. Frequent tillage or use of a polyethylene film with or without turnip resulted in a lower density of large tubers in November 2006 relative to fallow treatments, regardless of management intensity in bell pepper. The density of large tubers after 2 yr was similar among treatments involving frequent tillage or use of a polyethylene film with or without turnip, regardless of subplot treatment; this was also observed for medium tubers, but not for small tubers. All hand-weeded plots had comparable densities of small tubers, ranging from 25 to 194 viable tubers m−2. Intensive management involving frequent tillage or use of a translucent polyethylene film with or without turnip fb hand-weeding was not effective in eradicating purple nutsedge over two growing seasons. Purple nutsedge management costs calculated for each main-plot treatment revealed that use of a translucent polyethylene film alone was at least 4.5-fold more costly than frequent tillage. This research demonstrates that season-long management is essential to prevent purple nutsedge proliferation over time.
Cloning and Characterization of a Critical Meristem Developmental Gene (EeSTM) from Leafy Spurge (Euphorbia esula)
Authors: Varanasi Vijaya , Slotta Tracey , Horvath David
Published: July 2008

SHOOTMERISTEMLESS(STM) encodes a member of the class IKNOXhomeodomain protein family that is required for meristem development and maintenance. We have isolated both genomic and cDNA clones ofSTMfrom the perennial weed leafy spurge. A comparison to other class IKNOXgenes indicates thatEeSTMrepresents an orthologue ofAtSTMand not one of the other class IKNOXgene family members. 5′ rapid amplification of cDNA ends (RACE) indicated that the transcription initiation site is close to the start of translation and is conserved between arabidopsis and leafy spurge. Putativecis-acting elements were identified in theEeSTMpromoter, including a tuber-specific sucrose-responsive element, which could play a major role in the expression ofEeSTMin root tissue.
Weed Seed Pools Concurrent with Corn and Soybean Harvest in Illinois
Authors: Davis Adam S.
Published: July 2008

At the time of grain harvest, weed seeds can be classed into one of four pools on the basis of dispersal status and location: (1) undispersed, remaining on the mother plant; (2) dispersed in the current year, on the soil surface; (3) dispersed in the current year and collected by harvest machinery; and (4) dispersed in a previous year and persisting within the soil seed bank. Knowledge of the relative sizes of these seed pools for different weed species under different crop environments will be useful for determining the best way to reduce the size of inputs to the soil seed bank. In fall 2004 and fall 2005, four randomly selected commercially managed corn and soybean fields in east-central Illinois were sampled to quantify weed seed pools at time of crop harvest. Thirty randomly located 0.125-m2quadrats were placed within each field, the four seed pools mentioned above were sampled for each quadrat, and the species composition and abundance of each seed pool was determined. The magnitude of the weed seed rain varied among species and between years and crops. Twenty-six weed species were found to contribute to at least one of the four seed pools. However, the weed seed pools were consistently dominated by six species: velvetleaf,Amaranthuscomplex (redroot pigweed and waterhemp), ivyleaf morningglory, giant foxtail, prickly sida, and common cocklebur. For each of these species, the ratio of undispersed seeds to seeds in the soil seed bank at harvest time was ≥ 1 in at least one crop during one of the two experimental years, indicating a potential for the soil seed bank to be completely replenished or augmented by that year's seed rain. This analysis demonstrates the urgent need for techniques to limit weed seed inputs to the soil seed bank at the end of the growing season.
Vernalization Responses of Jointed Goatgrass (Aegilops cylindrica), Wheat, and Wheat by Jointed Goatgrass Hybrid Plants
Authors: Fandrich Lynn , Mallory-Smith Carol A. , Zemetra Robert S. , Hansen Jennifer L.
Published: July 2008

To assess the risk of gene movement between winter wheat and jointed goatgrass, information about the reproductive development of jointed goatgrass, winter wheat, and related hybrid plants is required. Seedlings from five jointed goatgrass populations, winter wheat, spring wheat, and jointed goatgrass by wheat reciprocal hybrid plants were exposed to 4, 7, or 10 C temperatures for 0, 2, 4, 5, 6, 6.5, 7, or 8 wk. Vernalized seedlings were transferred to a greenhouse set to 30/18 C day/night temperatures and 16-h photoperiod. Growth stages on all plants were recorded twice a week. All spring wheat and spring wheat related hybrid plants reproduced (as measured by the first reproductive node) in the absence of vernalization. Plants of jointed goatgrass population A-R, winter wheat, and winter wheat related hybrids were unlikely to reproduce in the absence of vernalization. Plants of jointed goatgrass populations B-W, G-S, E-S, and F-W reproduced in the absence of vernalization, and the likelihood that these plants would reproduce was different from all other plants. Plants that entered their reproductive phases together were not in synchronous development at anthesis. Plants in these studies differentially passed through the reproductive phases between the first reproductive node and anthesis. Our results demonstrate that variation in vernalization response exists among several jointed goatgrass populations, and reveal that the reproductive behavior of vernalized jointed goatgrass plants at anthesis is delayed compared to vernalized winter wheat and related hybrid plants. Hybrid plants produced between spring wheat and jointed goatgrass were vernalization insensitive. We hypothesize that hybridization between wheat and jointed goatgrass occurs as a result of cross-pollination between the younger reproductive tillers of jointed goatgrass and older reproductive tillers of wheat. The use of an early maturing wheat cultivar may exploit the difference in reproductive development and reduce the risk of hybrid production.
Interactions of ALS-Inhibiting Herbicide Residues in Three Prairie Soils
Authors: Geisel Bryce G. L. , Schoenau Jeff J. , Holm Frederick A. , Johnson Eric N.
Published: July 2008

The objective of this study was to determine if the presence of two acetolactate synthase (ALS)-inhibiting herbicide residues in different Saskatchewan soils would result in additive, synergistic, or antagonistic interactions. This was determined through field trials where herbicides were applied sequentially over the course of 2 yr. The herbicides examined in these experiments were imazamethabenz, flucarbazone, sulfosulfuron, and florasulam, each in combination with imazamox and imazethapyr. The phytotoxicity and persistence of the herbicides in soil was assessed using an oriental mustard root inhibition bioassay. The determination of herbicide interaction was made through the comparison of the experimentally observed values to theoretically expected values derived from a mathematical equation. On the basis of the bioassay analysis, it was found that the herbicide residue combinations resulting from sequentially applied ALS-inhibiting herbicides in the three soils produced additive injury effects rather than synergistic or antagonistic interactions.
Ozone Enhances Adaptive Benefit of Glyphosate Resistance in Horseweed (Conyza canadensis)
Authors: Grantz D. A. , Shrestha A. , Vu H-B.
Published: July 2008

Since the first identification of glyphosate resistance in horseweed in California in 2005, the glyphosate-sensitive (GS) biotype has become rare, whereas the glyphosate-resistant (GR) biotype has become dominant in the eastern San Joaquin Valley (SJV). This is an area exposed to regular usage of glyphosate and to high levels of ambient ground-level ozone (O3). A previous study showed that SJV biotypes of GR are more robust than GS in the absence of ozone. This advantage was reduced, though not eliminated, at elevated O3. This suggests that the rapid evolution of resistance to glyphosate was not linked to evolution of resistance to O3. In this study, we contrasted these responses to O3 in the presence of concurrent glyphosate pressure. The GR and GS biotypes differed in growth and injury, reflecting their known differential sensitivities to glyphosate, but responded similarly to O3 with no O3 × biotype interaction. Ozone imposed an unexpected, but ecologically important, impact that enhanced the performance advantage of GR over GS. In the presence of the combination of glyphosate and O3 the biomass of GR was reduced to low but viable levels, whereas the biomass of GS was reduced to nonviable levels that effectively removed it from the population. These data do not support a genetic linkage between resistance to glyphosate and to O3, but suggest that air pollution may have accelerated the fixation of glyphosate-resistance alleles in California horseweed populations.