bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Acrylic‐modified Acacia Gum Thickener: Preparation, Characterization and Rheological Properties
Authors: Nickzare Morteza , Zohuriaan‐Mehr Mohammad J. , Yousefi Ali A. , Ershad‐Langroudi Amir 
Published: March 2009

AbstractAcacia gum (Arabic gum; A‐gum) is a branched complex heteropolysaccharide with extremely high solubility and extraordinary Newtonian behavior in solution at concentrations even higher than 25%. In this work, A‐gum thickening properties were highly improved to form non‐Newtonian fluids in water at concentrations below 2%. The thickener was prepared by graft copolymerization of acrylonitrile onto A‐gum using ceric ammonium nitrate. The synthesized graft copolymers (differing in percentage and molecular weight of the grafted acrylic chains) were then alkaline‐hydrolyzed under various conditions (i.e. temperature, time and the NaOH concentration) to prepare the thickening agents. FTIR and elemental analyses were used for elucidating the structure of samples. Steady‐shear rheological properties of aqueous solutions of the thickener at variety of concentrations, temperatures and saline solutions were investigated in details.
Spectroscopic Characterisation of Cationic Quaternary Ammonium Starches
Authors: Pigorsch Enrico 
Published: March 2009

AbstractNear‐infrared, infrared and Raman spectra of native starch and cationic quaternary ammonium starches prepared by different reaction methods were recorded. An interpretation of the spectra is given that takes the structural changes of the starch molecules and the degree of substitution (DS) into consideration. The near‐infrared spectra of the cationic starches showed additional bands compared to native starch at about 6010 cm−1 and 4438 cm−1, which are assigned to the first overtone of the stretching vibration and to a combination band of the CH3 groups in the trimethyl ammonium substituent. No significant changes in the infrared spectra of the cationic starches could be observed due to strong absorption bands of OH and H2O. By contrast, the Raman spectra of the cationic starches showed characteristic bands of the trimethyl ammonium substituent at about 3030, 970 and 761 cm−1. Plots of the ratios of intensity of the 761 cm−1 band to an unchanged starch band at 938 cm−1 versus DS gave linear curves which could be used for DS determination. Furthermore, the use of a NIR calibration model for DS determination with a standard error of calibration (SECV) of 0.003 is reported.
Monophosphorylation of Acid‐thinned Starch to Enhance the Quality of Viscose Yarns Sized at Reduced Temperature
Authors: Zhu Zhifeng , Liu Zhijun 
Published: March 2009

AbstractAcid‐thinned cornstarch was monophosphorylated by reaction with orthophosphates to obtain an agent for sizing heat‐sensitive viscose warp yarns under reduced temperature. Influences of the modification and sizing temperature on paste behavior, adhesion to viscose fibers, and properties of sized viscose yarns were studied for a range of substitution of 0.021–0.082 and temperatures from 60°C to 95°C. The modification resulted in an increase in viscosity stability of the starch paste, enhancement of the adhesion to the viscose fibers, improvement of mechanical properties of the sized viscose yarns, and a decrease in hairiness of sized yarns even if the temperature of the starch paste was lowered to 60°C. The modification is capable of improving the sizing properties of starch for viscose yarns at 60–80°C when the degree of substitution with phosphate groups is about 0.05.
Does teaching experience matter? Examining biology teachers' prior knowledge for teaching in an alternative certification program
Authors: Friedrichsen Patricia J. , Abell Sandra K. , Pareja Enrique M. , Brown Patrick L. , Lankford Deanna M. , Volkmann Mark J. 
Published: March 2009

AbstractAlternative certification programs (ACPs) have been proposed as a viable way to address teacher shortages, yet we know little about how teacher knowledge develops within such programs. The purpose of this study was to investigate prior knowledge for teaching among students entering an ACP, comparing individuals with teaching experience to those lacking teaching experience. Of the four participants seeking secondary biology teaching certification, two participants had 2 years of prior biology teaching experience. We used the Lesson Preparation Method as a data collection tool, asking participants to create lesson plans to teach the concept of heritable variation. Primary data sources were the lesson plans and follow‐up interview transcripts. Prior teaching experience made little difference as both groups held didactic teaching orientations and wrote similar lesson plans. Both groups drew on general pedagogical knowledge (PK), and had little pedagogical content knowledge for teaching heritable variation. Teaching experience did appear to lead to more integration among PK components. The study includes implications for the teacher education, research, and policy. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 357–383, 2009
Research education of new scientists: Implications for science teacher education
Authors: Feldman Allan , Divoll Kent , Rogan‐Klyve Allyson 
Published: March 2009

AbstractThis study examined an interdisciplinary scientific research project to understand how graduate and undergraduate honors students learn to do science. It was found that the education of the students occurs as part of an apprenticeship. The apprenticeship takes place in research groups. In general, research groups are structured in two ways: loosely organized and tightly organized, and have characteristics of both communities of practice and epistemic communities. Students have different roles in the research groups: novice researcher, proficient technician, or knowledge producer. Their role depends on their knowledge and skills, and their degree programs. It is possible for students to develop expertise along a continuum from novice researcher to knowledge producer. The members of the research group, including the professor and other students, facilitate the development of the students along the continuum of roles. Implications for the education of science teachers are discussed. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 442–459, 2009
Aluminum induces chromosome aberrations, micronuclei, and cell cycle dysfunction in root cells of Vicia faba
Authors: Yi Min , Yi Huilan , Li Honghai , Wu Lihua 
Published: March 2009

AbstractAluminum (Al) exists naturally in air, water, and soil, and also in our diet. Al can be absorbed into the human body and accumulates in different tissues, which has been linked to the occurrence of Alzheimer's disease and various neurological disorders. By using Vicia cytogenetic tests, which are commonly used to monitor the genotoxicity of environmental pollutants, cytogenetic effects of aluminum (AlCl3) were investigated in this study. Present results showed that Al caused significant increases in the frequencies of micronuclei (MN) and anaphase chromosome aberrations in Vicia faba root tips exposed to Al over a concentration‐tested range of 0.01–10 mM for 12 h. The frequency of micronucleated cells was higher in Al‐treated groups at pH 4.5 than that at pH 5.8. Similarly, AlCl3 treatment caused a decrease in the number of mitotic cells in a dose‐ and pH‐dependent manner. The number of cells in each mitotic phase changed in Al‐treated samples. Mitotic indices (MI) decreased with the increases of pycnotic cells. Our results demonstrate that aluminum chloride is a clear clastogenic/genotoxic and cytotoxic agent in Vicia root cells. The V. faba cytogenetic test could be used for the genotoxicity monitoring of aluminum water contamination. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2010.
Enhanced low‐cost RFID protocol to detect relay attacks
Authors: Munilla Jorge , Peinado Alberto 
Published: March 2009

AbstractContactless smart cards are more and more used in access control and payment systems. However, most of such cards are vulnerable to relay attacks, also known as mafia fraud attacks. This attack requires simpler technical resources than tampering or cryptanalysis. In this the adversary deceives, the verifier into thinking that a genuine prover is close by relaying the messages between both genuine parties. The main countermeasure against this attack is the use of so‐called distance bounding protocols. In the radio frequency identification (RFID) framework, Hancke and Kuhn proposed the first distance bounding protocol, which resorts to an expensive and complex ultra wide band (UWB) radio link. Reid et al. remove this extra radio link and propose a low‐cost protocol, but some aspects still need to be further investigated. In this paper, we propose an enhanced low‐cost protocol which takes advantage of the special characteristics of the inductive communication in RFID, and the use of ‘void‐challenges’ to protect against relay attacks. The processing delay of this protocol is zero and it can be directly implemented on RFID devices, without resorting to any extra resources. We present experimental results to support our arguments. Copyright © 2009 John Wiley & Sons, Ltd.
Predictive Factors for Morbidity and Mortality in Patients Undergoing Laparoscopic Paraesophageal Hernia Repair: Age, ASA Score and Operation Type Influence Morbidity
Authors: Larusson Hannes J. , Zingg Urs , Hahnloser Dieter , Delport Karen , Seifert Burkhardt , Oertli Daniel 
Published: March 2009

AbstractBackgroundPatients undergoing laparoscopic paraesophageal hernia (PEH) repair risk substantial morbidity. The aim of the present study was to analyze predictive factors for postoperative morbidity and mortality.MethodsA total of 354 laparoscopic PEH repairs were analyzed from the database of the Swiss Association for Laparoscopic and Thoracoscopic Surgery (SALTS). Age (<70 and ≥70 years) and risk (low: American Society of Anesthesiologists (ASA) scores 1 + 2; high ASA scores 3 + 4) groups were defined and multivariate logistic regression was conducted.ResultsIn patients ≥70 years of age postoperative morbidity (24.4% versus 10.1%; p = 0.001) and mortality (2.4% versus 0%; p = 0.045) were significantly higher than in patients <70 years of age. In patients with gastropexy, this significant age difference was again present (38.8% versus 10.5%; p = 0.001) whereas in patients with fundoplication no difference between age groups occurred (11.9% versus 10.1%; p = 0.65). Mortality did not differ. High‐risk patients had a significantly higher morbidity (26.0% versus 11.2%; p = 0.001) but not mortality (2.1% versus 0.4%; p = 0.18). The multivariate logistic regression identified the following variables as influencing postoperative morbidity: Age ≥70 years (Odds Ratio [OR] 1.99 [95% CI 1.06 to 3.74], p = 0.033); ASA 3 + 4 (OR 2.29 [95% Confidence Interval (CI) 1.22 to 4.3]; p = 0.010); type of operation (gastropexy) (OR 2.36 [95% CI 1.27 to 4.37]; p = 0.006).ConclusionsIn patients undergoing laparoscopic paraesophageal hernia repair age, ASA score, and type of operation significantly influence postoperative morbidity and mortality. Morbidity is substantial among elderly patients and those with co‐morbidity, questioning the paradigm for surgery in all patients. The indication for surgery must be carefully balanced against the individual patient’s co‐morbidities, age, and symptoms, and the potentially life threatening complications.
Subsampling photographic capture‐recapture data of tigers (Panthera tigris) to minimize closure violation and improve estimate precision: a case study
Authors: Harihar Abishek , Pandav Bivash , Goyal Surendra Prakash 
Published: March 2009

AbstractMost studies using photographic capture‐recapture methodology estimate parameters of interest with ecological and sampling uncertainties. However, the effect of sampling effort on assumption violation and estimate precision has seldom been described using empirical data in studies estimating population size of tigers (Panthera tigris tigris). In this study, we evaluate the influence of trap effort (trap area, mean cell area and trap density) on the assumption of geographic closure and their relationship with estimated capture probability. We do this by subsampling capture histories obtained for tigers from 30 trapping stations within the Chilla range of Rajaji National Park, India. We assessed the importance of trapping effort on geographic closure by estimating fidelity () and immigration () under the Pradel model. Estimate precision (CV% []) was evaluated based on estimates of capture probability (). Results of the Pradel analysis suggested that larger trap area (TA) ensured geographic closure, while high trap densities (TD) exhibited sex‐specific heterogeneity in recapture probabilities p. Simulation results suggested a significant positive correlation between estimates of () and TD. With increase in estimated capture probability, estimate precision (CV% []) also improved sharply. Comparison of prior studies towards optimizing sampling strategies is often compromised due to the difference in scale and methods of sampling. Therefore, we urge that subsampling within a dataset as illustrated in our study may prove to be an advantageous step towards standardizing photographic capture‐recapture sampling methodology for management objectives.
Preparation of Ultrafine Fe–Pt Alloy and Au Nanoparticle Colloids by KrF Excimer Laser Solution Photolysis
Authors: Watanabe Masato , Takamura Hitoshi , Sugai Hiroshi 
Published: March 2009

Abstract
We prepared ultrafine Fe–Pt alloy nanoparticle colloids by UV laser solution photolysis (KrF excimer laser of 248 nm wavelength) using precursors of methanol solutions into which iron and platinum complexes were dissolved together with PVP dispersant to prevent aggregations. From TEM observations, the Fe–Pt nanoparticles were found to be composed of disordered FCC A1 phase with average diameters of 0.5–3 nm regardless of the preparation conditions. Higher iron compositions of nanoparticles require irradiations of higher laser pulse energies typically more than 350 mJ, which is considered to be due to the difficulty in dissociation of Fe(III) acetylacetonate compared with Pt(II) acetylacetonate. Au colloid preparation by the same method was also attempted, resulting in Au nanoparticle colloids with over 10 times larger diameters than the Fe–Pt nanoparticles and UV–visible absorption peaks around 530 nm that originate from the surface plasmon resonance. Differences between the Fe–Pt and Au nanoparticles prepared by the KrF excimer laser solution photolysis are also discussed.
Oligofructose and inulin modulate glucose and amino acid metabolism through propionate production in normal-weight and obese cats
Authors: Verbrugghe Adronie , Hesta Myriam , Gommeren Kris , Daminet Sylvie , Wuyts Birgitte , Buyse Johan , Janssens Geert P. J. 
Published: March 2009

The effect of dietary oligofructose and inulin supplementation on glucose metabolism in obese and non-obese cats was assessed. Two diets were tested in a crossover design; a control diet high in protein (46 % on DM basis), moderate in fat (15 %), low in carbohydrates (27 %), but no soluble fibres added; and a prebiotic diet, with 2·5 % of a mixture of oligofructose and inulin added to the control diet. Eight non-obese and eight obese cats were allotted to each of two diets in random order at intervals of 4 weeks. At the end of each testing period, intravenous glucose tolerance tests were performed. Area under the glucose curve (AUCgluc) was increased (P = 0·022) and the second insulin peak was delayed (P = 0·009) in obese compared to non-obese cats. Diets did not affect fasting plasma glucose concentrations, blood glucose response at each glucose time-point after glucose administration, AUCgluc, fasting serum insulin concentrations, area under the insulin curve, and height and appearance time of insulin response. Yet, analysis of acylcarnitines revealed higher propionylcarnitine concentrations (P = 0·03) when fed the prebiotic diet, suggesting colonic fermentation and propionate absorption. Prebiotic supplementation reduced methylmalonylcarnitine (P = 0·072) and aspartate aminotransferase concentrations (P = 0·025), both indicating reduced gluconeogenesis from amino acids. This trial evidenced impaired glucose tolerance and altered insulin response to glucose administration in obese compared to non-obese cats, regardless of dietary intervention; yet modulation of glucose metabolism by enhancing gluconeogenesis from propionate and inhibition of amino acid catabolism can be suggested.
Dehydroepiandrosterone activates cyclic adenosine 3′,5′-monophosphate/protein kinase A signalling and suppresses sterol regulatory element-binding protein-1 expression in cultured primary chicken hepatocytes
Authors: Tang Xue , Ma Haitian , Shen Zanming , Zou Sixiang , Xu Xijie , Lin Chengzhao 
Published: March 2009

Dehydroepiandrosterone (DHEA), a steroid hormone that is secreted by the adrenal cortex in mammals, has an array of biological actions, including inhibition of fat synthesis, decreasing the number of adipocytes, and a reduction in mammalian metabolic efficiency. Recent studies showed that DHEA may decrease fat deposition in poultry, but the mechanism of action is unclear. In the present study, we demonstrate that DHEA stimulates intracellular cyclic adenosine 3′,5′-monophosphate (cAMP) accumulation in chicken hepatocytes during a 30 min incubation period. Increases in intracellular cAMP are evoked by as low as 0·1 μm-DHEA. The cAMP induced by DHEA, while suppressing cAMP-specific phosphodiesterase activity, also activates cAMP-dependent protein kinase A (PKA) in chicken hepatocytes. In addition, the activation of PKA leads to down-regulation of sterol regulatory element-binding protein-1 (SREBP-1). These findings demonstrate that direct action by DHEA leads to activation of the cAMP/PKA signalling system in the modulation of lipid metabolism by repressing SREBP-1, thereby providing a novel explanation for some of the underlying effects proposed for DHEA in the prevention of fat deposition in poultry.
Supplemental zinc reduced intestinal permeability by enhancing occludin and zonula occludens protein-1 (ZO-1) expression in weaning piglets
Authors: Zhang Bingkun , Guo Yuming 
Published: March 2009

The present study was carried out to evaluate the pharmacological effect of Zn in diarrhoea in relation to intestinal permeability. Seventy-two weaning piglets, aged 24 d, were allocated to three dietary treatments: (1) control diet without supplemental Zn; (2) control diet supplemented with 2000 mg Zn/kg from ZnO; (3) control diet supplemented with 2000 mg Zn/kg from tetrabasic zinc chloride (TBZC). At the end of a 14 d experiment period, piglets were weighed, feed consumption was measured, and mucosal barrier function was determined using the lactulose/mannitol test. Expression of mucosal tight junction protein was measured at RNA and protein level. Inclusion of TBZC or ZnO in the diet significantly increased average daily gain (P < 0·01) and average daily feed intake (P < 0·05), while leading to reduced feed conversion ratio (P < 0·05) and faecal scores (P < 0·01). TBZC reduced urinary lactulose:mannitol ratios of weaning piglets (P < 0·05), while dietary supplementation with ZnO tended to reduce urinary lactulose:mannitol ratios (P = 0·061). ZnO or TBZC significantly enhanced the mRNA and protein expression of occludin (P < 0·05) and zonula occludens protein-1 (ZO-1) (P < 0·05) in the ileal mucosa. Piglets fed the TBZC-supplemented diet had a higher level of occludin than pigs fed the ZnO-supplemented diet (P < 0·05). The results indicate that Zn supplementation decreased faecal scores and the reduction was accompanied by reduced intestinal permeability, which was evident from the reduced urinary lactulose:mannitol ratios and increased expression of occludin and ZO-1. Therefore, the protective effect of pharmacological levels of dietary Zn in reducing diarrhoea might, at least partly, be associated with reduced intestinal permeability.
Double layer (DL) formation in laser-produced plasma
Authors: Eliezer Shalom , Ludmirsky Ariold 
Published: March 2009

It is shown that appropriate conditions for DL formation may be created in laser produced plasma. In particular, a ‘feedback’ mechanism is suggested:Wave instabilities → absorption of laser energy → inward heat flux → DL formation → heat flux inhibition → wave instabilitiesPlasma-target potentials and plasma-currents, produced by Nd. laser intensities (IL) between 1012 to 1015 W/cm2, were measured in situ. These measurements seem to be the first direct evidence of DLs in laser produced plasma. Electric fields of EDL ∼ 5 × 105 to 5 × 106 Volts/cm and widths of 10 to 100 Debye lengths are estimated for the DL.Scaling laws are derived for the measured extremum potentials (V) and currents (I): . Two different slopes were obtained experimentally, one slope equal to α = β = 1·0 for IL < 1014 W/cm2 and another of α = β = 0·4 for IL > 1014 W/cm2. These data are explained for temperature scaling law for the low irradiance and for the high irradiance. While the first scaling law is consistent with inverse bremsstrahlung absorption, the second scaling necessitates other absorption processes. Potential and current probes are suggested as useful devices in detecting wave plasma instabilities.
Laser produced plasma as an ion source for heavy ion inertial fusion
Authors: Barabash L. Z. , Koshkarev D. G. , Lapitskii Yu. I. , Latyshev S. V. , Shumshurov A. V. , Bykovskii Yu. A. , Golvbev A. A. , Kosyrev Yu. P. , Krechet K. I. , Haydarov R. T. , Sharkov B. Yu. 
Published: March 2009

The present paper presents experimental results of the transverse and longitudinal phase volume for the expanding multicharged ions in laser produced plasma, created by focusing a CO2-laser (beam) onto a Pb207 target. The total number of Pb207 ions (with Z = 1 or 2 and Z = 6), the ion current duration and amplitude at a distance of 1 m from the laser target within 10−2 steradians are determined. The measured experimental parameters of the laser heavy ion source are compared with the driver requirement for the heavy ion inertial fusion (HIIF) programme.The phenomena observed in the experiment confirm the results of numerical calculations using a two temperature hydrodynamic programme.
Comments on “A simple model of ion beam heated ICF targets” by R. G. Evans
Authors: Ahlborn Boye 
Published: March 2009

In a recent study R. G. Evans developed an analytic model for ICF targets heated by heavy ion beams in order to show the differences to laser beam heating. However, these differences are really not very pronounced. In fact, Evans' model should be directly applicable to describe exploding pusher foil targets. In addition, Evans' scaling law for the ablation pressure PA with target density ρ0 and particle beam intensity Ib,is identical to the scaling found for laser targets with tamped flow (Ahlborn, 1981).