bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil Chemical Properties in the Vicinity of Pores with and without Roots
Authors: Eich-Greatorex Susanne , Strand Line Tau
Published: March 2006

Rhizosphere conditions are of great importance for nutrient uptake and thus plant growth. Nutrient availability in the rhizosphere may differ substantially from that of the bulk soil and specific sampling of the rhizosphere soil is crucial to the understanding of plant growth, particularly where roots are restricted in growth due to high bulk density of the soil. The purpose of this study was to develop suitable methods for investigating the chemical composition of soil around pores with and without roots in soils with high bulk density. Two different methods were undertaken: one approach was to perform sequential extractions with H2O, 0.01, 0.1, and 1 M NH4NO3 on soil samples taken at different distances from the pore wall to determine differences in element availability. Another approach was to analyze resin‐impregnated, undisturbed soil samples from the same site for elemental composition of pore wall material using a scanning electron microscope (SEM) equipped with an x‐ray micro analyzer. In general, the sequential extraction detected few statistically significant differences in nutrient availability between pores containing roots compared with pores without roots. The SEM analysis showed lower amounts of easily weatherable minerals around pores containing roots. Both methods are suitable for investigating differences between rhizosphere and bulk soil characteristics.
Soil Morphology‐Water Table Cumulative Duration Relationships in Southern New England
Authors: Morgan Charles P. , Stolt Mark H.
Published: March 2006

Although redoximorphic features (RMFs) are commonly used in place of direct observation to estimate the depth of the seasonal high water table (SHWT), little is known about the relationships between RMFs and the duration of the water table. The objective of this study was to gain a better understanding of how the expression of RMFs relates to the depth and duration of the water table in moderately well‐drained soils of southern New England. The 20 soils studied included Dystrudepts, Quartzipsamments, and Psammaquents; of these, 17 met the criteria for Oxyaquic (8) or Aquic (9) subgroup classification. Water table levels were monitored for 18 mo from February to July of the following year to compare the depth and cumulative duration of the water table (cumulative saturation) to RMFs within soil horizons. Average seasonal high water table level (ASHWT) was correlated (p < 0.05) to the depth of the first loamy horizon with >2% RMFs (r2 = 0.65–0.72). Water table levels occurred within horizons with no RMFs for as much as 13% of the 18 mo study period. Mean cumulative saturation for soils with textures finer than loamy sand ranged from 3% for horizons with no RMFs to 36% for horizons with a depleted matrix. For horizons with textures of loamy sand and coarser, the mean cumulative saturation ranged from 8% for horizons with no RMFs to 45% for horizons with >2% depletions. (Percentage of cumulative saturation would have likely been less if we monitored for a full 2 yr, as the late summer and fall of the second year were not monitored.) Our results suggest that the abundance of RMFs increases as the percentage of time the water table is present within a horizon increases. Additionally, coarse‐textured horizons are less expressive in regards to RMF abundance than are loamy‐textured horizons with similar cumulative saturation. For land‐use decisions, soil morphology should be used to provide both an estimate of the depths of a defined SHWT and cumulative saturation.
An Accurate and Efficient Method for Sorting Biomass Extracted from Soil Cores Using Point‐Intercept Sampling
Authors: Wenk Rebecca C. , Battles John J. , Jackson Randall D. , Bartolome James W. , Allen-Diaz Barbara
Published: March 2006

We describe a point‐intercept sampling technique that reduces the time and therefore the cost associated with hand sorting biomass extracted from soil cores. Typically, organic material that has been extracted from soil cores is painstakingly separated into categories such as roots, leaves, and unidentifiable organic matter so that each can be weighed. With the point‐intercept method, we spread the extracted organic material over a grid and record the category of randomly located point intercepts within grid cells. The proportion of each category determined via point intercepts is then attributed to the total dry mass of the organic material. With a subset of our data, we determined ordinary least squares regression relationships between hand‐sorted (census) and point‐intercept (sample) estimates of the belowground biomass components roots, aboveground detritus, and soil organic matter. We then applied these regression models to the remainder of our data, which had been hand sorted to serve as a validation dataset. Using bootstrapped 95% confidence intervals of the ordinary least squares (OLS) bisector slope estimate, we found no significant differences between the point‐intercept and hand‐sorted values for all three belowground biomass components. The time saved sorting belowground biomass by the point‐intercept method (∼15 min core−1) allowed us to process 43% more cores during the same period. We applied the same technique to components of aboveground herbaceous biomass, but with less success because these pools tended to be less uniformly distributed throughout the sample layer. We recommend the approach for sorting belowground biomass components from soil cores, but the method requires more development before being used to sort other ecosystem components.
Culturable Escherichia coli in Soil Mixed with Two Types of Manure
Authors: Unc Adrian , Goss Michael J.
Published: March 2006

We evaluated the impact of the manure type used in soil–manure mixtures on the detection of culturable E. coli as tested in water quality monitoring. A series of incubation experiments, lasting up to 200 d, allowed evaluation of the potential impact of manure × soil interactions on the augmentation of culturable E. coli Two soil types (sandy loam and a silt loam), two manure types (liquid swine manure and solid beef cattle manure), and three temperature levels (4, 12, and 20°C) were investigated. The significance of the presence of competing microorganisms was estimated by comparing results from manure mixtures with sterile and nonsterile soils. Water content in the soil–manure mixtures was maintained close to field capacity to eliminate the specific impact of water availability. We found that culturability of the indicator organism, E. coli, changed with time and was dependent on the type of manure used and its interaction with soil. Escherichia coli could be cultured for a longer time from soils with liquid manure additions. Whereas E. coli numbers were initially higher from soils treated with solid beef cattle manure, their numbers decreased more rapidly and the duration of their apparent survival was shorter. Resilience of culturable E. coli was independent of their initial numbers in manure.
Antecedent Moisture Content and Aging Duration Effects on Seal Formation and Erosion in Smectitic Soils
Authors: Mamedov A. I. , Huang C. , Levy G. J.
Published: March 2006

Soil susceptibility to seal formation and erosion depends on its inherent properties and surface conditions. Our objective was to study the interaction of two different surface conditions, antecedent moisture content (AMC) and aging duration, on seal formation and erosion in four smectitic soils. Soil samples were packed in trays and wetted with different amounts of water (0, 1, 2, 3, 4, 6, 8, or 16 mm) with a mist type rain. The wetted samples were put in plastic bags and allowed to age for 0.01, 1, 3, or 7 d. The soil trays were exposed to 60 mm of distilled water rain of high energy. At no aging (0.01 d), runoff volume (a measure for seal development) and soil loss increased with an increase in AMC mainly because of enhanced slaking. In general, runoff and soil loss decreased with the increase in aging duration. For instance, in the Clay (Y) soil, to which 3 mm of water was added, as aging increased from 1 to 7 d, runoff decreased from 39 to 28 mm, and soil loss decreased from 660 to 397 g m2 For any given aging duration, the smallest runoff volume and soil loss were obtained at the intermediate AMC levels (2, 3, and 4 mm of water added); at this AMC range, increasing aging time resulted in up to 40% decrease in runoff or soil loss. The effects of aging at these AMC levels (generally between wilting point and field capacity [i.e., pF 4.1–2.4]) were significantly more pronounced for clay soils probably because at these AMCs water‐filled pores in the clay fabric were considered active in the stabilization process and the development of cohesive bonds between and within particles during the aging period. Soil erosion changed with the increase in aging duration in a manner similar to runoff, suggesting that runoff was the main precursor to erosion under these conditions.
Assessing Soil Hydrophobicity and Its Variability through the Soil Profile Using Two Different Methods
Authors: Buczko U. , Bens O.
Published: March 2006

Soil water repellency (hydrophobicity) and its heterogeneity in field soils under natural conditions can cause unstable wetting fronts, preferential flow, and accelerated solute leaching. For assessing possible effects of water repellency and its heterogeneity on flow processes in a given soil, investigations of both overall levels of repellency and its variability are necessary. The purpose of this study was to assess water repellency levels and its variability in sandy soils under a pine–beech forest transformation chronosequence. Water repellency was quantified at four plots for soil depths between 0 and 160 cm on disturbed and oven‐dried samples with the water drop penetration time (WDPT) test and the sessile drop method (SDM) (contact angles [CAs]). Intrasample variability was quantified with a heterogeneity index (HI) which is based on the difference between the 90 and 10% quantile, divided by the overall range of encountered values. For both methods and all plots, repellency levels were highest in the topsoil layer (0‐ to 10‐cm depth) and decreased clearly with increasing depth. Larger maximum values of intrasample variability were determined with the WDPT method compared to the SDM. When the proportion of estimated measurement error is subtracted from heterogeneity values, the average heterogeneity is higher for log(WDPT) (mean 8.9%) than for CAs (mean 6.7%). The preferential flow which was observed at this site despite the ostensible homogeneity of the soil may be due to the high variability of hydrophobicity, although other factors (e.g., funnel flow) may contribute to this as well.
Dairy Diet Impacts on Fecal Chemical Properties and Nitrogen Cycling in Soils
Authors: Powell J. M. , Wattiaux M. A. , Broderick G. A. , Moreira V. R. , Casler M. D.
Published: March 2006

Availability of manure nitrogen (N) to crops is mitigated by many factors including manure type and composition. Whereas relationships between dairy diets, milk production, manure N excretion, and urine N losses as ammonia have been documented, very little information exists on how diets impact fecal carbon (C), N content, and partitioning, and how these factors impact fecal N mineralization and plant N uptake after application to soil. Feces from 24 to 63 dairy cows (Bos taurus) fed 14 typical diets were incubated aerobically in a sandy loam and two silt loam soils, and soil inorganic N (IN) was determined periodically during a 365‐d period. Feces from 12 of the 14 diets were applied to the same soils and oat (Avena sativa L.), sorghum (Sorghum bicolor L. Moench), and sorghum ratoon dry matter (DM) and N uptake were determined over a 155‐d period. Feces from cows fed alfalfa (Medicago sativa L.) silage (AS)‐based diets generally lead to higher soil IN levels than soils amended with feces from corn (Zea mays L.) silage (CS)‐based diets, especially in soils amended with feces from CS‐low crude protein (LCP) diets; feces from AS‐based diets increased plant DM and N uptake; after application to a silt loam, feces from high crude protein (HCP) diets resulted in greater soil IN levels than feces from LCP diets; and feces from LCP diets did not impact soil IN but decreased plant DM and N uptake. Carbon to N (C/N) ratios of applied feces were found to be significant predictors of plant DM and N uptake. There appears to be a range of dietary options that satisfy nutritional requirements of high‐producing dairy cows and produce feces having differential effects on soil N mineralization and plant N uptake after application to soil.
Phosphorus Fractions in Soils of Taylor Valley, Antarctica
Authors: Blecker S. W. , Ippolito J. A. , Barrett J. E. , Wall D. H. , Virginia R. A. , Norvell K. L.
Published: March 2006

Phosphorus studies in the cold desert ecosystem of the Antarctic Dry Valleys have been largely confined to stream sediments and orthinogenic regions. Expanding P studies to soils may augment the understanding of P biogeochemistry and habitat suitability in this extreme environment. Our objectives were to examine P fractionation in Antarctic Dry Valley soils and sediments and compare their relationship to other soil biogeochemical data. Samples were obtained along transects perpendicular to the Harnish and Priscu streams in Lake Fryxell and Lake Bonney basins, respectively. We utilized a sequential inorganic P extraction procedure, analyzing for a series of labile through resistant P fractions. We further analyzed soils for labile organic P and biomass P. Results showed the amount of inorganic P increased from soluble to Ca‐bound P at both sites, with greater weathering of P‐bearing minerals at the Fryxell site inferred from the greater P levels found in most fractions as compared with the Bonney site. Fryxell site soluble P findings correlated positively with the Al‐bound phase, possibly facilitating P availability to microfauna. The P fraction distribution at both the Fryxell and Bonney sites fits the general relationship between weathering intensity and P distribution of other arid ecosystems.
Grandparents Raising Grandchildren: The Role of Social Support in Coping with Caregiving Challenges
Authors: Gerard Jean M. , Landry-Meyer Laura , Roe Jacqueline Guzell
Published: March 2006

In this investigation of 133 grandparents with primary responsibility for their grandchildren, we examined the potential moderating role of social support in the association between caregiver stressors and grandparents' general well-being. Enacted formal support buffered the association between grandchild health problems and both grandparent caregiving stress and life satisfaction. Enacted formal support also buffered the association between parenting daily hassles and life satisfaction. Compensatory or main effects of perceived informal and formal social support were found for both grandparent caregiving stress and life satisfaction. Findings highlight the importance of professional assistance and community services in minimizing the negative impact of child-related challenges on grandparents' well-being.
Guest Editorial: A Response to Patrick Moore's “Questioning the Motives of Technical Communication and Rhetoric: Steven Katz's ‘Ethic of Expediency’”
Authors: Katz Steven B.
Published: March 2006

In my 1992 College English article “The Ethic of Expediency: Classical Rhetoric, Technology, and the Holocaust” [1], I looked at the implications of a Nazi memo whose sole purpose was to improve the efficiency of the gassing vans, in order to begin to try to understand and discuss the negative uses and ethical abuses to which technical communication, and deliberative rhetoric generally, could be taken by the powerful and unscrupulous. In “Questioning the Motives of Technical Communication and Rhetoric: Steven Katz's ‘Ethic of Expediency’” [2], Patrick Moore accuses me of ignoring alternate translations, citing out of context, and focusing on the negative meaning of words to make my case. The point at issue in these charges, I believe, is whether (and to what degree) Aristotle meant to base deliberative discourse on “expediency.” I will take each of these charges up one at a time to explore them more thoroughly, discuss their interrelations, and then conclude with a few observations of my own.
Changing Patterns of Native American Trade in the Middle Atlantic Region and Chesapeake Watershed: A World Systems Perspective
Authors: Stewart Michael
Published: March 2006

Types of trade and trends in the movement of material goods within the Middle Atlantic Region and with adjacent regions is summarized beginning ca 2500 BC. The timing of cycles of trade and the social and cultural developments that may be linked to them are compared with developments in adjacent regions. While it is clear that native peoples of the Middle Atlantic and Chesapeake areas are interacting with their contemporaries in other geographic areas, trends in trade and socio-cultural developments are not synchronous. The world systems of the Chesapeake and Middle Atlantic Region after 2500 BC are relatively small and somewhat insular, at least in comparison with those of the Midwest and Southeast. Although there is evidence of interaction with cultures and societies in adjacent regions, this interaction is not systemic, especially as regards trade. No core-periphery differentiation appears to exist. There is no clear archaeological evidence of more economically and socially developed cultures dominating or exploiting less developed ones intra-regionally or inter-regionally prior to the time of Native-European contact.
Software Piracy among College Students: A Comprehensive Review of Contributing Factors, Underlying Processes, and Tackling Strategies
Authors: Liang Zhili , Yan Zheng
Published: March 2006

This article reviewed empirical studies published in the past 30 years that examined software piracy among college students. It focused on three areas of study: (a) major factors that affect college students' intentions, attitudes, and moral intensity regarding software piracy, (b) various decision-making processes that underlie software piracy behavior, and (c) technical, legal, and educational strategies that deal with college students' software piracy. Limitations of existing research and future research directions were discussed.
The Guido Site: A Multi-Component Pre-Contact Site in Marbletown, Ulster County, NY
Authors: Diamond Joseph E.
Published: March 2006

The Guido site is a multi-component pre-Contact site in the Esopus drainage in New York's Mid-Hudson Valley. It was almost entirely excavated by avocational archaeologists from 1975 to 1981. Occupations found on the site range from the Late Archaic Vosburg phase to the Terminal Late Woodland Esopus Indians. Settlement pattern information includes a possible Orient phase house pattern, and subsistence data consist of Late Woodland storage pits which have produced dated evidence for the cultivation and storage of maize from the Oak Hill phase to pre-Contact. One human burial, that of an adult aged 30-40 years, of indeterminate sex, was also found.
High-School Students' Regulation of Learning During Computer-Based Science Inquiry
Authors: Winters Fielding I. , Azevedo Roger
Published: March 2006

Sixty-two high-school biology students, paired heterogeneously based on prior knowledge, learned about genetic using GenScope, a computer-based learning environment (CBLE), over four 90-minute class periods. Differences between low and high prior knowledge students emerged with convergence of verbal process data and pre- and post-test product data. The low prior knowledge students gained significantly in conceptual understanding from pre- to post-test, whereas the high prior knowledge students' understanding did not significantly change. In an analysis of their verbalizations, low prior knowledge students regulated their learning by relying on their partners for cognitive and other regulatory support whereas the high prior knowledge students spent most of their time regulating their own learning or providing external support for their lower prior knowledge peer. The results of this naturalistic study can potentially be used to inform educational practice by highlighting scaffolds that may foster self-regulated learning in a CBLE-mediated science inquiry context.
Useful Metaphors for Tackling Problems in Teaching and Learning
Authors: Schwartz Marc S. , Fischer Kurt W.
Published: March 2006

Textbooks and lectures are typically structured around the belief that students learn the same way they would climb a ladder: straight up, one step at a time. Marc Schwartz and Kurt Fischer propose a pyramid and webs of pyramids as far more appropriate and useful metaphors.
Making Connections: Using Skill Theory to Recognize How Students Build and Rebuild Understanding
Authors: King Patricia M. , Vanhecke Jones R.
Published: March 2006

In this companion to Marc Schwartz and Kurt Fischer's article, Patricia King and JoNes VanHecke describe how student affairs educators can help students become sophisticated thinkers.
Sailing through Leadership Theory
Authors: Northup Kimberly R.
Published: March 2006

What do tacking, coming about, traffic control, and jib sheets have to do with leadership? At The University of Tampa, a program combining learning to sail with learning to lead is demonstrating that moving a group is very much like maneuvering a boat.
Choosing an operating policy for seeded batch crystallization
Authors: Ward Jeffrey D. , Mellichamp Duncan A. , Doherty Michael F.
Published: March 2006

Determination of the optimal temperature (or supersaturation) trajectory for a seeded batch crystallizer is a well studied problem. The majority of researchers find that the optimal trajectory has a greater supersaturation at the end of the batch. A significant minority of researchers, however, using very similar models and different but equally justifiable objective functions, find that the optimal trajectory has the greatest supersaturation at the beginning of the batch. Still other researchers have suggested that crystallization processes should be operated with constant supersaturation. These apparent conflicts are resolved into different equivalence classes of objectives and corresponding operating policies. It is shown that the equivalence classes arise as a result of an inherent tradeoff for seeded batch crystallizers involving secondary nucleation: Early growth operating policies tend to minimize the number of nuclei formed because supersaturation is greatest when the mass of crystals is least. However, those nuclei which are formed early have an opportunity to grow to a larger size and compete with the growth of the seed crystals. By contrast, late growth operating policies tend to produce more nuclei because supersaturation is greatest when the mass of crystals is greatest. However, nuclei formed late in the batch do not have a chance to grow as large, and the total mass of nucleus‐grown crystals is small. Which of these outcomes is preferred depends on the particular application. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Liquid‐liquid and liquid‐gas extraction of aroma compounds with hollow fibers
Authors: Viladomat Fabrice Gascons , Souchon Isabelle , Pierre François‐Xavier , Marin Michèle
Published: March 2006

The extraction of 15 aroma compounds from a highly diluted aqueous feed with hollow fiber membrane contactors was investigated. Membrane‐Based Solvent Extraction (MBSE) and Membrane Air‐Stripping (MAS) were tested with the aqueous feed cross‐flowing on the shell side and the stripping phase flowing in the lumen of the hollow fiber. Experimental results showed that globally, MBSE offered higher overall mass transfer coefficients than MAS. This difference was mainly explained by the gap in partition coefficients. Hexane‐water partition coefficients were about 10,000 times higher than air‐water partition coefficients. The contribution of each local resistance to mass transfer was identified by a resistance‐in‐series model. Mass transfer in the aqueous feed boundary layer is the limiting step in MBSE, while mass transfer in the stripping gas boundary layer is the limiting step in MAS. A diagnostic tool based on partition coefficients was developed in order to help choose the adequate process for the extraction of an aroma compound. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Biodegradability of diethylene glycol terephthalate and poly(ethylene terephthalate) fiber by crude enzymes extracted from activated sludge
Authors: Zhang Jianfei , Gong Jixian , Shao Gaiqin , Qin Jijie , Gu Zhenya
Published: March 2006

In this study, diethylene glycol terephthalate (DTP) and poly(ethylene terephthalate) (PET) fiber were degraded by crude enzymes extracted from a strain that was isolated from activated sludge obtained from factories. The feasibility of the biodegradation of the PET fiber is discussed through the rule of the biodegradation of DTP, which was used as the simulacrum of the biodegradation of the PET fiber. We concluded that the proper conditions for the degradation of DTP with the crude enzyme were 30°C and a medium pH. Through the degradation kinetics, we determined that the crude enzyme was more capable of degrading DTP than was lipase. In addition, the crude enzyme also degraded the PET fibers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3855–3859, 2006
Effect of screw axial vibration on polymer melting process in single‐screw extruders
Authors: Qu Jinping , Zeng Guansheng , Feng Yanhong , Jin Gang , He Hezhi , Cao Xianwu
Published: March 2006

A model for investigating the melting process of polymer in a vibration‐induced single‐screw (VISS) extruder is presented. The key feature of this model is as follows: vibration force field is introduced into the overall course of extrusion by the axial vibration of the screw, and the velocity distribution in the polymer melt behaves strongly nonlinear and time‐dependent. To analyze this model, half‐open barrel visible experimental method and low‐density polyethylene material are adopted to investigate the effect of the vibration parameters on the melting process, which goes into further details of study and research on the melting mechanism, and thus, a novel physical melting model is derived. Combining the conservation equations of mass, movement, energy, and constitutive, analytical expressions of the melting rate, the energy consumption, the length of melting section, and the distribution of solid bed are obtained. This model enables the prediction of the processing and design parameters in the VISS extruders from which the optimum conditions for designing VISS extruder and polymer processing are obtained. The theory is supplemented by a calculation sample and experiment, which shows that the introduction of vibration force field can improve the melting capacity and decrease the power consumption of extruder greatly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3860–3876, 2006
Thermal properties of poly(maleic anhydride‐alt‐acrylic acid) in the presence of certain metal chlorides
Authors: Kavlak Serap , Kaplan Can Hatice , Rzaev Zakir M. O. , Güner Ali
Published: March 2006

Polychelates were synthesized by the addition of aqueous solutions of copper(II), cadmium(II), and nickel(II) chlorides to aqueous solutions of poly(maleic anhydride‐alt‐acrylic acid) [poly(MA‐alt‐AA)] in different pH media. The thermal properties of poly(MA‐alt‐AA) and its metal complexes were investigated with thermogravimetry and differential scanning calorimetry (DSC) measurements. The polychelates showed higher thermal stability than poly(MA‐alt‐AA). The thermogravimetry of the polymer–metal complexes revealed variations of the thermal stability by complexation with metal ions. The relative thermal stabilities of the systems under investigation were as follows: poly(MA‐alt‐AA)–Cd(II) > poly(MA‐alt‐AA)–Cu(II) > poly(MA‐alt‐AA)–Ni(II) > poly(MA‐alt‐AA). The effects of pH on the complexation and gravimetric analysis of the polychelates were also studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3926–3930, 2006
Siloxane surfactant‐modified clay and its effect in reinforcing the laminate of polymethylsilsesquioxane
Authors: Li Bai‐Yu , Ma Jun , Liu Hai‐Yun , Guo Xing‐Lin , Zhang Xiao‐Li , Xu Jian
Published: March 2006

To achieve good compatibility between clay layers and siloxane polymer, polymethylsilsesquioxane (PMSQ), montmorillonite was modified by a novel siloxane surfactant with M̄w = 1900 and then environmentally friendly solution‐compounded with PMSQ to prepare glass fiber laminates. Transmission electronic microscope shows the orderly, exfoliated structure of the modified clay in PMSQ matrix; scanning electronic microscope demonstrates the fine dispersion of the clay layers in the matrix because of the good compatibility between the grafted surfactant and the matrix. Both the modified clay and its nanocomposite indicate much improved thermal stability. By incorporation of merely 0.3 wt % of the clay, the flexural modulus and strengths of fiber/PMSQ laminate are increased by 21 and 62%, respectively. This study illuminates the importance of the compatibility of the grafted siloxane surfactant with the matrix polymer in achieving both exfoliation and dispersion of clay as well as ideal mechanical properties for silicone‐based polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3974–3980, 2006
Naturally occurring amino acid: Novel curatives for chloroprene rubber
Authors: Das A. , Naskar N. , Datta R. N. , Bose P. P. , Debnath S. C.
Published: March 2006

Polychloroprene is a diene rubber, but unlike other diene rubbers, its compounding with various additives and curing mechanisms is different. A derivative of thiourea, ethylene thiourea (ETU), is widely used to vulcanize chloroprene rubber (CR), and the vulcanizates thus obtained exhibit excellent mechanical properties, good aging resistance, and very good sealing properties. However, the problem is that ETU is reported to be a potent carcinogenic compound, and hence, the effective substitution for ETU has been extensively explored. In this study, we used a naturally occurring amino acid derivative, dimethyl L‐cystine, as an ecofriendly compound for the vulcanization of CR. It had a significant influence on the curing characteristics and mechanical properties, such as modulus, tensile strength, elongation at break, and hardness values. The concentration of this novel crosslinking agent and also the curing temperature were optimized. In the presence of dimethyl L‐cystine, the amount and activity of magnesium oxide also exhibited significant influences on the crosslinking characteristics. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3981–3986, 2006
Photocatalytic degradation of poly(ethylene oxide) and polyacrylamide
Authors: Vijayalakshmi S. P. , Madras Giridhar
Published: March 2006

The photocatalytic degradation of poly(ethylene oxide) (PEO) and polyacrylamide (PAM) was investigated using combustion synthesized nano‐sized TiO2 catalyst (CSN‐TiO2). The degradation was conducted with two different UV lamps of 125 and 80 W. Degradation of PEO was observed in both the cases, whereas PAM degraded only when exposed to lamp of higher power, even in the presence of catalyst. Gel permeation chromatography was used to determine the molecular weight distribution. Continuous distribution kinetics was applied to determine the kinetics of the photodegradation process. The degradation rate coefficients of the polymers in the presence of combustion synthesized TiO2 were higher than the degradation rate coefficients obtained with commercially available TiO2 (Degussa P‐25). The enhanced degradation rate of the polymers when catalyzed by CSN‐TiO2 can be due to the nano‐size, high surface area, and the presence of hydroxyl groups on the surface of the catalyst. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3997–4003, 2006
Mica reinforced nylon‐6: Effect of coupling agents on mechanical, thermal, and dielectric properties
Authors: Bose S. , Raghu H. , Mahanwar P. A.
Published: March 2006

The effects of applying titanate (TYZOR® TPT) and silane (DYNASYLAN VTMO) coupling agents to wet ground muscovite mica in nylon‐6 composites are described. Nylon‐6 composites of 5–40 wt % filler loadings were compounded using an APV Baker twin‐screw extruder. Mica (25 wt %) brought about an increase in the Young's modulus, flexural strength, and flexural modulus but did not produce significant variations in tensile and impact strength. Hence different coupling agents were employed. It was observed that titanate coupling agent improved the tensile strength and the Young's modulus of the composites much while the impact properties were enhanced by the silane coupling agent. An attempt was made to use ϵ‐caprolactum in improving the interfacial adhesion of the filler and the matrix. It was observed that ϵ‐caprolactum improved the flexural modulus of the composites most. The effect of coupling agents on the dielectric strength, heat distortion temperature, and morphology were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4074–4081, 2006
Reducing hoarding behavior with individualized reinforcement and item return
Authors: Berry Cynthia L. , Schell R. M.
Published: March 2006

Treatment research on hoarding is generally limited to people without intellectual disabilities who have symptoms of obsessive compulsive disorder and respond favorably to cognitive‐based therapies. We evaluated the effects of individualized reinforcement and item return procedures on hoarding behavior in a multiple baseline across three persons with severe mental retardation. Systematic preference assessment procedures identified items used in the individualized reinforcement procedures. Reductions in hoarding behavior occurred for each person when individualized treatment and item return procedures were applied. These reductions were maintained when direct support staff were trained to provide treatment. Copyright © 2006 John Wiley & Sons, Ltd.
Development of Antiviral Fusion Inhibitors: Short Modified Peptides Derived from the Transmembrane Glycoprotein of Feline Immunodeficiency Virus
Authors: D'Ursi Anna Maria , Giannecchini Simone , Esposito Cinzia , Alcaro Maria Claudia , Sichi Olimpia , Armenante Maria Rosaria , Carotenuto Alfonso , Papini Anna Maria , Bendinelli Mauro , Rovero Paolo
Published: March 2006

Feline immunodeficiency virus (FIV) is a naturally occurring pathogen that causes an AIDS‐like syndrome in domestic cats and is a valuable model system by which criteria for antiviral vaccines and drugs development can be tested. The cell‐entry step of the lentivirus life cycle is regarded as a promising target for the development of new generation inhibitors. We have previously described potent in vitro anti‐FIV activity associated with a synthetic octapeptide, termed C8 (Ac‐Trp‐Glu‐Asp‐Trp‐Val‐Gly‐Trp‐Ile‐NH2), containing the Trp‐rich motif of FIV transmembrane glycoprotein, which shares a common structural framework with the corresponding molecule of HIV and appears to play a similar role in cell entry. In this report, in an attempt to develop simpler potential fusion inhibitors to be tested in vivo, we describe further studies focused on synthetic peptide analogues of C8. Since C8 inhibitory activity is dependent upon the Trp motif, we systematically replaced these residues with bulky and/or aromatic natural and unnatural amino acids, in order to develop a rational structure–activity relationship. Furthermore, the amino acids located between the Trp residues, which are not crucial for inhibitory activity, were replaced by simple alkyl spacers of appropriate length. Design, NMR structural analysis, in vitro anti‐FIV activity in lymphoid cell cultures, and serum stability of these new analogues are reported. The final results indicate that a simpler hexapeptide (Ac‐Nal2‐Ape‐Nal2‐Ape‐Nal2‐Ile‐NH2; Nal2=3‐naphthalen‐2‐yl‐L‐alanine, Ape=5‐aminopentanoic acid), almost entirely made up of unnatural amino acid residues, has markedly increased enzymatic stability, while maintaining strong antiviral potency in vitro.
Aptamer to Ribozyme: The Intrinsic Catalytic Potential of a Small RNA
Authors: Brackett David M. , Dieckmann Thorsten
Published: March 2006

The discovery of RNA‐based catalysis 23 years ago dramatically changed the way biologists and biochemists thought of RNA. In the recent past, several ribozymes structures have provided some answers as to how catalysis is accomplished and how it relates to RNA structure and folding. However, there is still little information as to how catalytic activity evolved. Here we show that the small malachite green‐binding aptamer has intrinsic catalytic potential that can be realized by designing the proper substrate. The charge distribution within the RNA binding pocket stabilizes the transition state of an ester hydrolysis reaction and thus accelerates the overall reaction. The results suggest that electrostatic forces can contribute significantly to RNA‐based catalysis. Moreover, even simple RNA structures that have not been selected for catalytic properties can have a basic catalytic potential if they encounter the right substrate. This provides a possible starting point for the molecular evolution of more complex ribozymes.
Entwicklung eines integrierten Prozesses zur enzymatischen Herstellung von Biotensiden aus nachwachsenden Rohstoffen
Authors: del Amor Villa E. M. , Wichmann R.
Published: March 2006

Wegen der vielfältigen Einsatzmöglichkeiten von Biotensiden besteht großes Interesse an der Entwicklung neuer Herstellungsverfahren, vor allem aus nachwachsenden billigen und leicht zugänglichen Rohstoffen wie Zuckern bzw. Fetten/Ölen oder deren Derivaten. Untersucht wird zusätzlich zur Veresterungsreaktion auch die Abtrennung der Nebenprodukte und die Aufarbeitung und Isolierung der Produkte.
Die chemische Industrie als Innovationsmotor für den Klimaschutz
Authors: Rudolph J.
Published: March 2006

Die chemische Industrie hat ihren eigenen Ressourcenverbrauch und damit die Emission von Treibhausgasen in den letzten Jahrzehnten erheblich eingeschränkt. Dieser Erfolg beruht auf einem umfassenden Ansatz, der von der energetische Optimierung ganzer Standorte bis hin zur Verbesserung einzelner Apparate, Prozesse und Reaktionen reicht. Über die Einschränkung ihres eigenen Verbrauchs an fossilen Rohstoffen hinaus trägt die chemische Industrie als Schlüsselindustrie und Innovationsmotor für viele Industriezweige durch ihre Produkte und Lösungen wesentlich zur Einsparung von Energie in anderen Branchen bei. Beispiele hierfür sind die CO2‐Sequestrierung und die Gebäudetechnik. Darüber hinaus erleichtern Innovationen aus der Chemie auch die Erschließung regenerativer Rohstoff‐ und Energiequellen.
Entwicklungsmöglichkeiten der CO2‐Rückhaltung in Kraftwerken aus thermodynamischer Sicht
Authors: Göttlicher G.
Published: March 2006

Emissionsfreie Kraftwerke mit CO2‐Rückhaltung und ‐Speicherung sind mit heutiger Technik mit erheblichem Investitions‐ und Energieaufwand bereits machbar. Die Speicherpotenziale erscheinen ausreichend groß, sind jedoch im Detail noch zu ungenau erforscht. Der großtechnische Einsatz der CO2‐Rückhaltung steht noch am Anfang einer Entwicklung, so dass das Optimierungspotenzial durch Forschung und Entwicklung noch sehr groß ist. Zur Einschätzung der Entwicklungspotenziale wurden die thermodynamischen Einflussfaktoren analysiert. Es zeigt sich, dass die Wirkungsgradverbesserung auch bei CO2‐Rückhaltung weiter forciert werden muss. Eine Optimierungsstrategie im System der CO2‐Rückhaltung ist, die Verdünnung von Verbrennungsprodukten mit Luftstickstoff zu vermeiden. Als zukunftsweisende Methode stellt sich die Anreicherung von CO2 unter selektiver Zumischung von Sauerstoff dar.
Clinical features and correlates of gemcitabine‐associated lung injury
Authors: Belknap Steven M. , Kuzel Timothy M. , Yarnold Paul R. , Slimack Nicholas , Lyons E. Allison , Raisch Dennis W. , Bennett Charles L.
Published: March 2006

BACKGROUND

Gemcitabine is a commonly used chemotherapeutic agent structurally and pharmacologically similar to cytarabine. Recently, instances of severe gemcitabine‐associated lung injury have been reported. Herein, investigators affiliated with the Research on Adverse Drug Events and Reports (RADAR) pharmacovigilance program evaluated clinical characteristics of gemcitabine‐associated severe acute lung injury from clinical trial reports, medical literature case reports, and spontaneous reports to the Food and Drug Administration (FDA) Adverse Event Reporting System (AERS).

METHODS

Clinical data were obtained by reviewing adverse event case reports for gemcitabine‐associated lung injury as reported in the medical literature and in the FDA AERS database. Upper limit estimates of ADE rate were derived from review of published clinical trials reporting gemcitabine‐associated lung injury rates of 10% or higher.

RESULTS

A total of 178 reports of gencitabine‐associated lung injury were identified; in AERS, there were 55 cases from clinical trials and 92 spontaneous reports. A comprehensive search revealed 31 medical literature reports. Clinical features of gemcitabine‐associated lung injury included dyspnea, fever, pulmonary infiltrate, and cough with recognition of toxicity occurring after a median duration of 48 (range, 1‐529) days after initiation of gemcitabine. The taxanes, docetaxel and paclitaxel, were frequently reported as coadministered therapies. Eleven Phase II or Phase III clinical trials with 317 patients identified gemcitabine‐associated lung injury rates of greater than 10%, with the highest rates (22% and 42%) being observed in Phase III clinical trials where Hodgkin disease patients were treated with a regimen that included gemcitabine and bleomycin.

CONCLUSIONS

High rates of gemcitabine‐associated severe lung injury were observed when gemcitabine was combined with other therapies known to also cause lung injury. Physicians should have a high index of suspicion for this toxicity and report the relevant clinical findings to the FDA's AERS. Cancer 2006. © 2006 American Cancer Society.
Why do men choose one treatment over another?
Authors: Zeliadt Steven B. , Ramsey Scott D. , Penson David F. , Hall Ingrid J. , Ekwueme Donatus U. , Stroud Leonard , Lee Judith W.
Published: March 2006

Treatment choices for localized prostate cancer appear to vary widely, although it is unclear whether this variation is a result of patient values or other factors. The authors conducted a systematic review of the literature, identifying 70 articles that focused on prostate cancer decision making. Studies suggest that men consider several issues when making treatment decisions. The authors found conflicting evidence regarding the importance that men place on cancer eradication, with considerable variation in how patients interpret evidence regarding treatment efficacy. The number of physicians that men see and the importance of the physician recommendation were found to vary considerably. Although men stated that side effects are important, few patients reported that side effect factors ultimately influenced their treatment choice. To the authors' knowledge, there is little research regarding how patients' personal values shape and influence their decision, or the role of race/ethnicity or socioeconomic status in preferences for treatment. The authors conclude that variations in treatment decisions may be more indicative of differences in the information patients receive rather than truly reflective of underlying patient preferences. Considerable progress is needed in helping patients fully understand how to balance the complex issues surrounding prostate cancer treatment decision making. Cancer 2006. © 2006 American Cancer Society.
JC‐1, a sensitive probe for a simultaneous detection of P‐glycoprotein activity and apoptosis in leukemic cells
Authors: Chaoui Driss , Faussat Anne‐Marie , Majdak Patricia , Tang Ruoping , Perrot Jean‐Yves , Pasco Sabine , Klein Christophe , Marie Jean‐Pierre , Legrand Ollivier
Published: March 2006

Background

JC‐1 probe has been successfully used for the analysis of either apoptosis or P‐glycoprotein (P‐gp) activity. Therefore, we wanted to see if JC‐1 could also simultaneously assess both, P‐gp activity and apoptosis, in acute myeloid leukemia (AML) cells.

Methods

P‐gp activity was measured using JC‐1 and compared to the results of the Rhodamine 123 (Rh 123) assay in P‐gp negative and P‐gp positive cell lines, and 12 AML samples. For apoptosis, spontaneous apoptosis, as well as, apoptosis induced by Cytosine Arabinosine and Homoharringtonine were analyzed. Both mitochondrial red fluorescence and cytoplasmic green fluorescence of JC‐1 with and without a P‐gp inhibitor (Cyclosporine A : CsA) were used for the identification of apoptotic cells, and this was compared to Annexin V/PI staining.

Results

(1) We found a good correlation between JC‐1 and Rh 123 in viable cells. Even in a small population of viable cells, P‐gp positive cells emitting low red fluorescence, gained on red fluorescence after P‐gp inhibition with CsA permitting an evaluation of P‐gp activity. (2) We found a good correlation between the Annexin V/PI staining and JC‐1 (P < 0.0001) in the assessment of apoptotic cells. Most importantly, the apoptotic cells could be distinguished by the loss of red fluorescence and the increase of green fluorescence without any change after P‐gp inhibition with CsA.

Conclusions

JC‐1 can simultaneously evaluate two important parameters involved in drug resistance in AML cells, P‐gp activity and apoptosis. © 2006 International Society for Analytical Cytology
Do temperamentally shy children process emotion differently than nonshy children? Behavioral, psychophysiological, and gender differences in reticent preschoolers
Authors: Theall‐Honey Laura A. , Schmidt Louis A.
Published: March 2006

We examined regional brain electrical activity (EEG), heart rate, and subjective responses at rest and during the presentation of videoclips designed to elicit a range of emotions (e.g., sadness, anger, happiness, fear) among a sample of healthy 4‐year‐old children selected for temperamental shyness. We found that shy children exhibited significantly greater relative right central EEG activation at rest and during the presentation of the fear‐eliciting videoclip than nonshy children. Shy females displayed greater relative right mid‐frontal EEG activation during the sad, happy, and fear videoclips than shy males who displayed greater relative left mid‐frontal EEG activation. These results (1) suggest that recent frontal EEG activation/emotion models might be gender‐specific and (2) appear to provide the first empirical evidence for recent theoretical notions linking the origins and maintenance of temperamental shyness in children to difficulty in regulating fear responses. © 2006 Wiley Periodicals, Inc. Dev Psyshobiol 48: 187–196, 2006.