bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and thermal behavior of inorganic–organic hybrid geopolymer composites
Authors: Hussain M. , Varely R. , Cheng Y. B. , Mathys Z. , Simon G. P. 
Published: January 2005

AbstractInorganic geopolymer potassium aluminosilicate was prepared at room temperature by the reaction of kaolin, potassium silicate, and potassium hydroxide solution and was dispersed in situ into an epoxy matrix by various proportions to fabricate novel inorganic–organic hybrid geopolymer composites. The formation of inorganic geopolymer with respect to time was monitored by X‐ray diffraction and FT‐IR analysis and confirmed that 30 min is required to complete the geopolymerization. When geopolymers were properly mixed at different ratios with organic polymers such as epoxy and cured, these hybrid polymers exhibit significant thermal stability. Pure kaolin was also incorporated into the epoxy matrix to compare the change in chemical and thermal properties. Cone calorimetry results showed about 27% decreased in rate of heat release (RHR) on addition of 20% pure kaolin. However, about 57% of RHR was decreased on addition of only 20% geopolymer. Evaluation of CO2 and CO were found to be minimum 2.0 and 0.7 kg/kg, respectively, for hybrid geopolymer composites compared to very high yield for epoxy at 3.5 kg/kg after 200 s of ignition. The current study shows that due to the high thermal stability of hybrid geopolymer composites, the novel hybrid geopolymer composites have the ability to be potential candidates to use in practical application where fire is of great concern. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 112–121, 2005
Drying biodegradable poly(hydroxybutyrate‐co‐3‐hydroxyvalerate) gels in the elongated state to improve their mechanical properties
Authors: Venkitachalam Rajesh , Mark James E. , Noda Isao 
Published: January 2005

AbstractPolyhydroxyalkanoates are a class of biodegradable polymers that may be used more as environmentally friendly materials if their mechanical properties can be improved. We approached this goal by modifying poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) with a well‐established processing technique involving crosslinking the polymer chains and then drying a swollen gel of the network under uniaxial strain. The mechanical properties of the resulting oriented films were determined in continuous extension as a function of the degree of crosslinking and the extent of strain during the drying process. Crosslinking invariably improved the toughness. Similarly, the subsequent orientation of the process generally increased the toughness as well, but in some cases, a reduction in the extensibility offset the increase in the ultimate stress at break and yielded reduced values of the toughness. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1519–1523, 2005
Acute effects of pulsed microwaves and 3‐nitropropionic acid on neuronal ultrastructure in the rat caudate‐putamen
Authors: Seaman Ronald L. , Phelix Clyde F. 
Published: January 2005

AbstractUltrastructure of the medium sized “spiny” neuron in rat dorsal‐lateral caudate‐putamen was assessed after administration of 3‐nitropropionic acid (3‐NP) and exposure to pulsed microwaves. Sprague–Dawley male rats were given two daily intraperitoneal doses of 0 or 10 mg/kg 3‐NP and 1.5 h after each dose were exposed to microwave radiation at a whole body averaged specific absorption rate (SAR) of 0 (sham exposure), 0.6, or 6 W/kg for 30 min. Microwave exposure consisted of 1.25 GHz radiation delivered as 5.9 μs pulses with repetition frequency 10 Hz. Tissue samples taken 2–3 h after the second sham or microwave exposure showed no injury with light microscope methods. Blinded qualitative assessment of ultrastructure of randomly selected neurons from the same samples did reveal differences. Subsequent detailed, quantitative measurements showed that, when followed by sham exposure, administration of 3‐NP significantly increased endoplasmic reticulum (ER) intracisternal width, ER area density, and nuclear envelope thickness. Microwave exposure at 6 W/kg alone also significantly increased these measures. Exposure of 3‐NP treated animals at 6 W/kg significantly increased effects of 3‐NP on ultrastructure. Although exposure at 0.6 W/kg alone did not affect ultrastructure measures, exposure of 3‐NP treated animals at 0.6 W/kg reduced the effects of 3‐NP. We concluded that 3‐NP changed neuronal ultrastructure and that the microwave exposures used here changed neuronal ultrastructure in ways that depended on microwave SAR and neuron metabolic status. The apparent cancellation of 3‐NP induced changes by exposure to pulsed microwaves at 0.6 W/kg indicated the possibility that such exposure can protect against the effects of mitochondrial toxins on the nervous system. Bioelectromagnetics 26:82–101, 2005. Published 2005 Wiley‐Liss, Inc.
Daily repeated magnetic field shielding induces analgesia in CD‐1 mice
Authors: Prato Frank S. , Robertson John A. , Desjardins Dawn , Hensel Jennifer , Thomas Alex W. 
Published: January 2005

AbstractWe have recently observed that a single exposure of mice to a magnetically shielded environment can attenuate opioid induced analgesia. Here, we report the effect of repeated exposures to the same magnetically shielded environment. Adult male Swiss CD‐1 mice were placed in a Mu‐metal™ lined box or an opaque Plexiglas™ box (sham condition) for 1 h per day for 10 consecutive days. Nociception was measured as the latency time to a foot lift/lick in response to an aversive thermal stimulus (hotplate analgesiometer, 50 ± 1 °C) before and immediately after exposure. Multiple experiments were conducted in which thermal latency was tested on each of the 10 days or on days 1, 5, and 10, with some utilizing post‐exposure testing only. It was shown that mice can detect and will respond to the repeated absence of the ambient magnetic field, with a maximum analgesic response occurring over days 4–6 of exposure and returning to baseline thereafter. The effect was robust, independent of pre‐exposure and intermittent testing, and seems to be opioid related, since the results obtained on day 5 were similar to those from a 5 mg/kg dose of morphine and were abolished with the opioid antagonist, naloxone. Bioelectromagnetics 26:109–117, 2005. © 2005 Wiley‐Liss, Inc.
Modulation of the catalytic activity of free and immobilized peroxidase by extremely low frequency electromagnetic fields: dependence on frequency
Authors: Portaccio M. , De Luca P. , Durante D. , Grano V. , Rossi S. , Bencivenga U. , Lepore M. , Mita D.G. 
Published: January 2005

AbstractA study of the influence of electromagnetic fields (EMF) of various frequencies, from 50 up to 400 Hz, on the catalytic activity of soluble and insoluble horseradish peroxidase (POD) was carried out. To simulate the conditions in which the enzyme operates in vivo, the POD was immobilized by entrapment on a gelatin membrane or by covalent attachment on a nylon graft membrane. The rate of inactivation of the soluble POD was found to exhibit positive and negative interactions with the 1 mT applied magnetic field, with an optimum positive effect at 130 Hz. The immobilized PODs, on the contrary, do not exhibit negative interactions, but show a maximum positive interaction at 150 Hz when entrapped and at 170 Hz when covalently attached. At 50 Hz and at frequencies higher than 250 Hz no effects were observed with insoluble POD. The optimum frequency of positive interaction between the EMF and the catalytic activity of the insoluble enzymes is shifted with respect to that of the soluble enzymes towards higher frequencies, the size of the shifts being dependent on the intensity of the physical forces involved in the immobilization process. Bioelectromagnetics 26:145–152, 2005. © 2005 Wiley‐Liss, Inc.
Morphological anomalies in pollen tubes of Actinidia deliciosa (kiwi) exposed to 50 Hz magnetic field
Authors: Dattilo Arduino M. , Bracchini Luca , Loiselle Steven A. , Ovidi Elisa , Tiezzi Antonio , Rossi Claudio 
Published: January 2005

AbstractThe role of the pollen grain, with respect to the reproductive process of higher plants, is to deliver the spermatic cells to the embryo sac for egg fertilisation. Delivery occurs through the pollen tube, a self produced organ that is generated when the pollen grain reaches the stigma surface. The effect of magnetic fields on pollen tube growth was reported in a recent publication by Germanà et al. Pollen tube growth is an interesting candidate for the detailed study of the effects of electromagnetic fields on cytoplasmic structures and organelles. In this research Actinidia deliciosa (kiwifruit) pollen grains were germinated in the presence of an alternating magnetic field (50 Hz). Our results, although of preliminary nature, show that pollen tube growth is affected by magnetic fields. The analysis of the observed anomalies in the pollen tube appear to be the result of changes in the ionic charges within the pollen tube cytoplasm. Bioelectromagnetics 26:153–156, 2005. © 2005 Wiley‐Liss, Inc.
A numerical and experimental comparison of human head phantoms for compliance testing of mobile telephone equipment
Authors: Christ Andreas , Chavannes Nicolas , Nikoloski Neviana , Gerber Hans‐Ulrich , Poković Katja , Kuster Niels 
Published: January 2005

AbstractA new human head phantom has been proposed by CENELEC/IEEE, based on a large scale anthropometric survey. This phantom is compared to a homogeneous Generic Head Phantom and three high resolution anatomical head models with respect to specific absorption rate (SAR) assessment. The head phantoms are exposed to the radiation of a generic mobile phone (GMP) with different antenna types and a commercial mobile phone. The phones are placed in the standardized testing positions and operate at 900 and 1800 MHz. The average peak SAR is evaluated using both experimental (DASY3 near field scanner) and numerical (FDTD simulations) techniques. The numerical and experimental results compare well and confirm that the applied SAR assessment methods constitute a conservative approach. Bioelectromagnetics 26:125–137, 2005. © 2005 Wiley‐Liss, Inc.
Impulsivity, self‐control, and delay discounting in persons with acquired brain injury
Authors: Dixon Mark R. , Jacobs Eric A. , Sanders Scott , Guercio John M. , Soldner James , Parker‐Singler Susan , Robinson Ashton , Small Stacey , Dillen Jeffrey E. 
Published: January 2005

AbstractThe present paper describes two studies in which participants with and without acquired brain injuries were compared on a temporal discounting task involving various hypothetical amounts of money available at varying delay values. During Experiment 1, both groups of participants were presented with choices between amounts of money ranging from 1 to 1000 US dollars at delays from 1 week to 10 years. The results obtained from this procedure were consistent with previous models of temporal delay discounting for control group participants, yet not for the majority of the participants with acquired brain injuries. During Experiment 2, adjustments in hypothetical amounts and delays were made whereby the amounts of money ranged from 1 to 20 US dollars at delays from 1 day to 1 year. These manipulations yielded data generally consistent with temporal delay discounting models previously reported in the published literature. The utility of using delay discounting procedures as a means of assessing impulsivity in persons with acquired brain injuries is presented. Copyright © 2005 John Wiley & Sons, Ltd.
Effects of therapist gender and type of attention on assessment and treatment of attention‐maintained destructive behavior
Authors: LeBlanc Linda A. , Hagopian Louis P. , Marhefka Jean M. , Wilke Arthur E. 
Published: January 2005

AbstractAdult attention frequently serves as a maintaining variable for problem behavior (Iwata et al., 1994). In addition, different aspects of attention such as the content of a statement or the person delivering the attention may moderate the rate of problem behavior and potentially affect treatment outcome (Fisher, Ninness, Piazza, & Owen‐DeSchryver, 1996). In the current study, we examined the effects of two variables hypothesized to affect the rate of attention‐maintained aggression in an adolescent female with profound mental retardation: gender of therapist and type of attention (physical versus verbal). The initial study examined the results of functional analyses conducted with therapists of different genders. An analysis was then conducted to determine the main and interaction effects of therapist gender and type of attention on the effectiveness of noncontingent reinforcement. The results indicate that each variable affected the rate of problem behavior (i.e., main effects) and that the two variables combined to produce an even greater effect (i.e., interaction effect) for males than for females. Next, we examined the impact of therapist gender on the effectiveness of an alternative intervention (functional communication training with extinction). The results support the initial hypotheses that therapist gender impacted both assessment and intervention results for this adolescent female. Copyright © 2001 John Wiley & Sons, Ltd.
Reducing stereotypic behavior through discrimination training, differential reinforcement of other behavior, and self‐monitoring
Authors: Shabani Daniel B. , Wilder David A. , Flood William A. 
Published: January 2005

AbstractThe effect of a treatment package designed to reduce stereotypic body rocking was examined in a child diagnosed with autism. After baseline, the participant was taught to discriminate between inappropriate (e.g. sitting in a chair and rocking) and appropriate (e.g. sitting in a chair without rocking) behavior. During intervention, both a therapist and the participant himself monitored the occurrence of rocking behavior. A non‐resetting 5 min differential reinforcement of other behavior (DRO) schedule was also introduced. A multiple baseline across behaviors (sitting and standing) design was used to evaluate the effects of the intervention package. The results indicated that the intervention was effective in eliminating body rocking. In addition, the DRO schedule was successfully increased to 20 min for sitting and 17 min for standing and the treatment was successfully introduced at the child's school. Copyright © 2001 John Wiley & Sons, Ltd.
Inclusion complexes of nabumetone with β‐cyclodextrins: thermodynamics and molecular modelling studies. Influence of sodium perchlorate
Authors: Goyenechea Nerea , Sánchez Miguel , Vélaz Itziar , Martín Carmen , Martínez‐Ohárriz Ma Cristina , González‐Gaitano Gustavo 
Published: January 2005

AbstractFluorescence, 1H‐NMR and molecular mechanics have been used to study the inclusion complexes of nabumetone (4,6‐methoxy‐2‐naphthyl‐butan‐2‐one; NAB) with β‐cyclodextrin (β‐CD), randomly methylated‐β (Mβ‐CD) and hydroxypropyl‐β‐cyclodextrins (HPβ‐CD). The emission spectrum of NAB shows a maximum whose fluorescence intensity increases with the different β‐CDs growing concentrations. This phenomenon allows calculation of the stability constants at 15, 25, 37 and 45°C. The thermodynamic parameters ΔH° and ΔS° for the inclusion process were obtained from the temperature dependence of the stability constants. Molecular mechanics calculations, together with proton NMR measurements, for the complex with β‐CD prove that the complex can be formed by penetration through any of the rims, with the naphthalene nucleus included and the substituents outside the cavity. The influence of NaClO4 in the aforementioned complexes has been analysed by spectrofluorimetric measurements. It has been found that the stability constants for the complexes decrease with the salt concentration; the causes are discussed. Copyright­© 2001 John Wiley & Sons, Ltd.
Extraordinary hyperconjugation of the methyl group in the S1 state of 8‐methylquinoline
Authors: Yang Rong , Schulman Stephen G. 
Published: January 2005

Abstract8‐Methylquinoline is unique among the monomethylquinolines in the red‐shift it shows in the absorption band derived from the short axis polarized (1La ← 1A) electronic transition, relative to that in quinoline itself. The effect is even more pronounced in the 8‐methylquinolinium cation, with the 1La band clearly emerging on the long‐wavelength side of the 1Lb band, which is normally the longest wavelength absorption band in quinolines substituted with weakly interacting functional groups. The fluorescences of 8‐methylquinoline and its conjugate acid show a pH dependence which is typical of N‐heterocylic bases that undergo hydrolysis in the lowest excited singlet state. These observations are explained in terms of hyperconjugation in the lowest excited singlet state, with electronic charge being swept into the quinoline ring by coupling of the short‐axis polarized transition of the ring system with the electrons of the methyl group in the 8‐position of the ring. Copyright © 2001 John Wiley & Sons, Ltd.
Membrane fusion induced by a lipopeptidic epitope from VP3 capside protein of hepatitis A virus
Authors: Chávez Abelardo , Pujol Montserrat , Alsina M. Asunción , Cajal Yolanda 
Published: January 2005

AbstractPalmitoyl‐VP3(110–121) (PVP3) is a synthetic lipopeptide derivative of a continuous epitope from the VP3 capsid protein of hepatitis A virus, and it is highly immunogenic in vivo. We have investigated the interaction of PVP3 with lipid model membranes of varying surface charge. Binding of PVP3 to anionic vesicles of PC/SM/PE/PS; (PC) 1‐palmitoyl‐2‐oleoyl‐phosphatidylcholine, (SM) sphingomyelin, (PE) 1,2‐dipalmitoyl‐phosphatidylethanolamine and (PS) L‐α‐phosphatidyl‐L‐serine, a composition that mimics the lipid component of natural membranes, was determined by tryptophan fluorescence and quenching experiments. In addition, and given the anionic net charge of the lipopeptide, binding to zwitterionic (PC/SM/PE) and cationic PC/SM/PE/DOTAP (DOTAP) 1,2‐dioleoyl‐3‐trimethylammonium‐propane mixtures was also determined. PVP3 binds to all three types of vesicles, but it adopts different forms depending on the electrical charge of the interface. This conclusion is supported by the insertion of PVP3 into lipid monolayers of the same charges spread at the air–water interface. The bound lipopeptide has membrane‐destabilizing effects in all three vesicle compositions, as demonstrated by leakage of vesicle contents, whereas lipid mixing only occurs in cationic liposomes. Our results provide useful information for the design of a liposomal system that promotes a direct delivery of the membrane‐incorporated immunogen to the immunocompetent cells, potentially increasing the immune response from the host. Copyright © 2001 John Wiley & Sons, Ltd.
Reporter cell lines are useful tools for monitoring biological activity of nuclear receptor ligands
Authors: Balaguer Patrick , Boussioux Anne‐Marie , Demirpence Ediz , Nicolas Jean‐Claude 
Published: January 2005

AbstractTo characterize the specificity of synthetic compounds for nuclear receptors, we established stable cell lines expressing the luciferase gene and different wild‐type or chimaeric receptors. MCF‐7 cells, which express the oestrogen receptor α (ERα), and HeLa cells, which do not express the oestrogen receptor, were transfected with a plasmid containing the luciferase gene downstream from a minimum promoter (β‐globin) and an oestrogen‐responsive element, generating the MELN and the HELN cell lines, respectively. MELN cells enabled the detection of compounds that bind to the ERα or interfere with its pathway. HELN cells were used to establish stable transfectants expressing different nuclear receptors containing the DNA‐binding domain of the oestrogen receptors. We thus established ERα or ERβ reporter cell lines by transfecting ERα or ERβ expression plasmids, and also retinoic acid receptor α, β or γ reporter cell lines by transfecting the chimaeric RAR gene, in which the DNA‐binding domain was replaced by the ERα DNA‐binding domain. Copyright © 2001 John Wiley & Sons, Ltd.
Interaction study of peptide from VP3 capsid protein of hepatitis A virus through monolayers and fluorescence spectroscopy
Authors: Sospedra P. , Prat J. , Haro I. , Mestres C. , Busquets M. A. 
Published: January 2005

AbstractA synthetic peptide with the sequence [Lys113]VP3(110–121): FWRKDLVFDFQV, corresponding to an epitope of the VP3 capsid protein of hepatitis A virus (HAV), was synthesized by solid phase and characterized. To obtain insight into its physicochemical properties and to understand its possible mechanism of action at the membrane level, interaction with DPPC or DPPC/DPPG (95/5) liposomes and lipid monolayers of DPPC, DPPG, SA, PS, PA and SM were studied by fluorescence spectroscopy and Langmuir–Blotgett films technique, respectively. Fluorescence studies showed that the peptide was in a hydrophobic environment when DPPC liposomes were used. The addition of a 5% of a charged lipid, DPPG, to the preparations changed the preference of the peptide towards a polar surrounding. However, the peptide had a high surface activity (nmol/L) and was able to incorporate into lipid monolayers. Interaction was higher with charged phospholipids than with neutral ones. These results may have physiological significance in the mechanism of infection of host hepatic cells by HAV. Copyright © 2001 John Wiley & Sons, Ltd.
Attempt to separate the fluorescence spectra of adrenaline and noradrenaline using chemometrics
Authors: Nikolajsen Rikke P.H. , Hansen Åse Marie , Bro Rasmus 
Published: January 2005

AbstractAn investigation was conducted on whether the fluorescence spectra of the very similar catecholamines adrenaline and noradrenaline could be separated using chemometric methods. The fluorescence landscapes (several excitation and emission spectra were measured) of two data sets with respectively 16 and 6 samples were measured, the smaller data set with higher resolution and i.e. precision. The samples were artificial urine (pH ≃ 3) spiked with the catecholamines in the concentration ranges 40–1200 nmol/L and 5.5–18 µmol/L, respectively. Unfold partial least squares regression (Unfold‐PLSR) on the larger data set and parallel factor analysis (PARAFAC) of the six samples of the smaller set showed that there was no difference between the fluorescence landscapes of adrenaline and noradrenaline. It can be concluded that chemometric separation of adrenaline and noradrenaline is not obtainable using this type of fluorescence measurement. Raman scatter, which overlaps the catecholamine spectra, was shown not to have any influence on the models calculated. Copyright © 2001 John Wiley & Sons, Ltd.
A fibre‐optic calcium ion sensor using a calcein derivative
Authors: Sloan W. D. , Uttamlal M. 
Published: January 2005

AbstractThis paper describes the development of a new fibre‐optic calcium ion sensor based on the immobilization of the calcein derivative, calcein acrylamide (CA) onto an optical fibre. The method involves the covalent attachment of CA in a polymer which itself is covalently bonded to an optical fibre. The fluorescence of CA is pH‐sensitive in the region 4–12 and also increases as a function of Ca2+ concentration at pH > 12. Typically, the indicator is sensitive to Ca2+ in the concentration range 0–20 µmol/L, with a linear region occurring when the concentration of calcium is equal to or below that of CA. The binding ratio of Ca2+ to CA in the linear calibration region is 1:1 and beyond the linear region is 2:1. The calcium‐sensitive polymer is prepared using photo‐initiated polymerization of a stock solution containing CA, monomer, a crosslinker and a photo‐initiator. The monomer units used were acrylamide and acrylamide doped with MAPTAC. The fluorescence characteristics of bound CA in acrylamide are similar to that of CA in solution. However, the cationic nature of the polymer doped with MAPTAC allows analysis of Ca2+ to be carried out in pH 8.5 solution. The Ca2+ sensing range of the sensor is typically 0–12 µmol/L. Copyright © 2001 John Wiley & Sons, Ltd.