bluuebunny/crossref_metadata_2025 huggingface dataset:
Intraperitoneal Cefazolin and Ceftazidime Effects on Human Peritoneal Mesothelial Cell Release of Cancer Antigen–125
Authors: Manley Harold J , Elwell Rowland J , Bailie George R , Welch Charles L
Published: November 2004

BACKGROUND

Intraperitoneal (IP) cefazolin and ceftazidime are recommended as empiric treatment for peritoneal dialysis (PD)–associated peritonitis. Human peritoneal mesothelial cells (HPMCs) may be affected by high IP cefazolin and ceftazidime concentrations. Peritoneal dialysate cancer antigen–125 (CA-125) appearance rate can be used to measure HPMC damage.

OBJECTIVE

To determine whether IP cefazolin and ceftazidime increase peritoneal CA-125 appearance rate.

METHODS

The study consisted of 2 phases. In phase I, no antibiotic was administered, and in phase II, patients received IP cefazolin and ceftazidime (15 mg/kg rounded to nearest 100 mg). Phase II occurred immediately after phase I. Each phase used a 4-hour dwell time with 2 L of dextrose 2.5% dialysate. Dialysate samples were collected at 0, 0.5, 1, 2, and 4 hours during each phase. Samples were assayed for CA-125, and CA-125 appearance rate was calculated.

RESULTS

Thirteen patients were recruited (7 men; aged 44.0 ± 16.0 y). The mean ± SD (range) CA-125 dialysate concentration after phases I and II were 6.6 ± 3.7 U/mL (2.3–15.0) and 6.4 ± 3.8 U/mL (1.6–13.8), respectively (p = 0.46). The CA-125 appearance rate after phases I and II were 51.9 ± 31.3 U/min/1.73 m2 (13.8–113.0) and 50.5 ± 32.9 U/min/1.73 m2 (11.0–104.0), respectively (p = 0.57). The slopes of the regression lines of CA-125 appearance rate were not significantly different between phases I and II.

CONCLUSIONS

These findings demonstrate that concurrently administered IP cefazolin and ceftazidime have no effect on HPMC release of CA-125 in non-infected PD patients.
Decreased Signs of Nicotine Withdrawal in Mice Null for the β4 Nicotinic Acetylcholine Receptor Subunit
Authors: Salas Ramiro , Pieri Fredalina , De Biasi Mariella
Published: November 2004

Withdrawal from chronic exposure to nicotine, the main addictive component of tobacco, produces distinctive symptoms in humans. The appearance of these symptoms is a major deterrent when people try to quit smoking. To study which type of nicotine receptor is relevant for the onset of the withdrawal syndrome, we used a mouse model of nicotine withdrawal. Wild-type mice and mice null for the β4 (β4-/-) or the β2 (β2-/-) nicotinic acetylcholine receptor subunits were implanted with osmotic minipumps delivering 24 mg · kg-1· d-1nicotine for 13 d. Subsequently, a single intraperitoneal injection of the nicotinic receptor antagonist mecamylamine induced behavioral symptoms of withdrawal measured as increased grooming, chewing, scratching, and shaking, plus the appearance of some unique behaviors such as jumping, leg tremors, and cage scratching. Mecamylamine injection triggered comparable withdrawal signs in wild-type and in β2-/- mice, whereas the β4-/- mice displayed significantly milder somatic symptoms. In addition, nicotine withdrawal produced hyperalgesia in wild-type but not β4-/- mice. Finally, chronic nicotine produced an increase in epibatidine binding in several areas of the brain in both wild-type and in β4-/- mice, but such receptor upregulation did not correlate with the severity of withdrawal signs.

Our results demonstrate a major role for β4-containing nicotinic acetylcholine receptors in the appearance of nicotine withdrawal symptoms. In contrast, the β2 subunit does not seem to greatly influence this phenomenon. We also show that the upregulation of epibatidine binding sites attributable to chronic nicotine, an effect associated with β2-containing receptors, is probably not related to the mechanisms underlying withdrawal.
Independent Coding of Movement Direction and Reward Prediction by Single Pallidal Neurons
Authors: Arkadir David , Morris Genela , Vaadia Eilon , Bergman Hagai
Published: November 2004

Associating action with its reward value is a basic ability needed by adaptive organisms and requires the convergence of limbic, motor, and associative information. To chart the basal ganglia (BG) involvement in this association, we recorded the activity of 61 well isolated neurons in the external segment of the globus pallidus (GPe) of two monkeys performing a probabilistic visuomotor task. Our results indicate that most (96%) neurons responded to multiple phases of the task. The activity of many (34%) pallidal neurons was modulated solely by direction of movement, and the activity of only a few (3%) pallidal neurons was modulated exclusively by reward prediction. However, the activity of a large number (41%) of single pallidal neurons was comodulated by both expected trial outcome and direction of arm movement. The information carried by the neuronal activity of single pallidal neurons dynamically changed as the trial progressed. The activity was predominantly modulated by both outcome prediction and future movement direction at the beginning of trials and became modulated mainly by movement-direction toward the end of trials. GPe neurons can either increase or decrease their discharge rate in response to predicted future reward. The effects of movement-direction and reward probability on neural activity are linearly summed and thus reflect two independent modulations of pallidal activity. We propose that GPe neurons are uniquely suited for independent processing of a multitude of parameters. This is enabled by the funnel-structure characteristic of the BG architecture, as well as by the anatomical and physiological properties of GPe neurons.
Functional-Anatomic Correlates of Memory Retrieval That Suggest Nontraditional Processing Roles for Multiple Distinct Regions within Posterior Parietal Cortex
Authors: Shannon Benjamin J. , Buckner Randy L.
Published: November 2004

Current theories of posterior parietal cortex (PPC) function emphasize space-based attention and motor intention. Imaging studies of long-term memory have demonstrated PPC activation during successful memory retrieval. Here, we explored the relationship between memory processes and classical notions of PPC function. Study 1 investigated old-new recognition using picture and sound stimuli to test whether PPC memory effects were dependent on visuospatial attention. A region lateral to the intraparietal sulcus [inferior parietal lobule complex (IPLC)] and two regions in the medial PPC [precuneus complex (PCC) and posterior cingulate/retrosplenial cortex (pC/Rsp)] showed strong retrieval success effects for both picture and sound stimuli. Study 2 explored a recognition task with varied response contingencies to investigate whether these retrieval success effects are dependent on motor intentions. In one condition, subjects responded to both old and new items. In two other conditions, subjects responded only to old or only to new items. IPLC, PCC, and pC/Rsp continued to show retrieval success effects with similar magnitudes for all response contingencies, including a condition in which no responses were made to old items. In a third study, IPLC and PCC activity was modulated at retrieval based on levels of processing at study, suggesting sensitivity to memory demands. These studies demonstrate that retrieval success effects in lateral and medial PPC regions are not affected by manipulations predicted by classical theories of PPC function but can be modulated by memory-related manipulations. PPC regions thus have prominent response properties associated with memory, which may arise through interactions with medial temporal cortex.
Insulin-Like Growth Factor-I Accelerates the Cell Cycle by Decreasing G1Phase Length and Increases Cell Cycle Reentry in the Embryonic Cerebral Cortex
Authors: Hodge Rebecca D. , D'Ercole A. Joseph , O'Kusky John R.
Published: November 2004

Neurogenesis in the developing cerebral cortex of mice occurs in the dorsal telencephalon between embryonic day 11 (E11) and E17, during which time the majority of cortical projection neurons and some glia are produced from proliferating neuroepithelial cells in the ventricular zone. The number of cells produced by this process is governed by several factors, including cell cycle kinetics and the proportion of daughter cells exiting the cell cycle after a given round of cell division. Thein vivoeffects of IGF-I on cell cycle kinetics were investigated in nestin/IGF-I transgenic (Tg) embryos, in which IGF-I is overexpressed in the cerebral cortex and dorsal telencephalon. These Tg mice have been shown to exhibit increased cell number in the cortical plate by E16 and increased numbers of neurons and glia in the cerebral cortex during postnatal development. Cumulative S phase labeling with 5-bromo-2′-deoxyuridine revealed a decrease in total cell cycle length (TC) in Tg embryos on E14. This decrease in TCwas found to result entirely from a reduction in the length of the G1phase of the cell cycle from 10.66 to 8.81 hr, with no significant changes in the lengths of the S, G2, and M phases. Additionally, the proportion of daughter cells reentering the cell cycle was significantly increased by 15% in Tg embryos on E14-E15 compared with littermate controls. These data demonstrate that IGF-I regulates progenitor cell division in the ventricular zone by reducing G1phase length and decreasing TCbut increases cell cycle reentry.
Role of Mitogen-Activated Protein Kinase Activation in Injured and Intact Primary Afferent Neurons for Mechanical and Heat Hypersensitivity after Spinal Nerve Ligation
Authors: Obata Koichi , Yamanaka Hiroki , Kobayashi Kimiko , Dai Yi , Mizushima Toshiyuki , Katsura Hirokazu , Fukuoka Tetsuo , Tokunaga Atsushi , Noguchi Koichi
Published: November 2004

To investigate whether activation of mitogen-activated protein kinase (MAPK) in damaged and/or undamaged primary afferents participates in neuropathic pain after partial nerve injury, we examined the phosphorylation of extracellular signal-regulated protein kinase (ERK), p38 MAPK, and c-Jun N-terminal kinase (JNK) in the L4 and L5 dorsal root ganglion (DRG) in the L5 spinal nerve ligation (SNL) model. We first confirmed, using activating transcription factor 3 and neuropeptide Y immunoreactivity, that virtually all L4 DRG neurons are spared from axotomy in this model. In the injured L5 DRG, the L5 SNL induced the activation of ERK, p38, and JNK in different populations of DRG neurons. In contrast, in the uninjured L4 DRG, the L5 SNL induced only p38 activation in tyrosine kinase A-expressing small- to medium-diameter neurons. Intrathecal ERK, p38, and JNK inhibitor infusions reversed SNL-induced mechanical allodynia, whereas only p38 inhibitor application attenuated SNL-induced thermal hyperalgesia. Furthermore, the L5 dorsal rhizotomy did not prevent SNL-induced thermal hyperalgesia. We therefore hypothesized that p38 activation in the uninjured L4 DRG might be involved in the development of heat hypersensitivity in the L5 SNL model. In fact, the treatment of the p38 inhibitor and also anti-nerve growth factor reduced SNL-induced upregulation of brain-derived neurotrophic factor and transient receptor potential vanilloid type 1 expression in the L4 DRG. Together, our results demonstrate that the L5 SNL induces differential activation of MAPK in injured and uninjured DRG neurons and, furthermore, that MAPK activation in the primary afferents may participate in generating pain hypersensitivity after partial nerve injury.
Synaptic Targeting by Alzheimer's-Related Amyloid β Oligomers
Authors: Lacor Pascale N. , Buniel Maria C. , Chang Lei , Fernandez Sara J. , Gong Yuesong , Viola Kirsten L. , Lambert Mary P. , Velasco Pauline T. , Bigio Eileen H. , Finch Caleb E. , Krafft Grant A. , Klein William L.
Published: November 2004

The cognitive hallmark of early Alzheimer's disease (AD) is an extraordinary inability to form new memories. For many years, this dementia was attributed to nerve-cell death induced by deposits of fibrillar amyloid β (Aβ). A newer hypothesis has emerged, however, in which early memory loss is considered a synapse failure caused by soluble Aβ oligomers. Such oligomers rapidly block long-term potentiation, a classic experimental paradigm for synaptic plasticity, and they are strikingly elevated in AD brain tissue and transgenic-mouse AD models. The current work characterizes the manner in which Aβ oligomers attack neurons. Antibodies raised against synthetic oligomers applied to AD brain sections were found to give diffuse stain around neuronal cell bodies, suggestive of a dendritic pattern, whereas soluble brain extracts showed robust AD-dependent reactivity in dot immunoblots. Antigens in unfractionated AD extracts attached with specificity to cultured rat hippocampal neurons, binding within dendritic arbors at discrete puncta. Crude fractionation showed ligand size to be between 10 and 100 kDa. Synthetic Aβ oligomers of the same size gave identical punctate binding, which was highly selective for particular neurons. Image analysis by confocal double-label immunofluorescence established that >90% of the punctate oligomer binding sites colocalized with the synaptic marker PSD-95 (postsynaptic density protein 95). Synaptic binding was accompanied by ectopic induction of Arc, a synaptic immediate-early gene, the overexpression of which has been linked to dysfunctional learning. Results suggest the hypothesis that targeting and functional disruption of particular synapses by Aβ oligomers may provide a molecular basis for the specific loss of memory function in early AD.
Induction of Brain Region-Specific Forms of Obesity by Agouti
Authors: Kas Martien J. H. , Tiesjema Birgitte , van Dijk Gertjan , Garner Keith M. , Barsh Gregory S. , Brake Olivier Ter , Verhaagen Joost , Adan Roger A. H.
Published: November 2004

Disruption of melanocortin (MC) signaling, such as by ectopic Agouti overexpression, leads to an obesity syndrome with hyperphagia, obesity, and accelerated body weight gain during high-fat diet. To investigate where in the brain disruption of MC signaling results in obesity, long-term Agouti expression was induced after local injections of recombinant adeno-associated viral particles in selected brain nuclei of adult rats. Agouti expression in the paraventricular nucleus, a hypothalamic region with a high density of MC receptors, induced acute onset hyperphagia and rapid weight gain that persisted for at least 6 weeks. In contrast, obesity and hyperphagia developed with a 3 week delay when Agouti was expressed in the dorsal medial hypothalamus. Agouti expression in the lateral hypothalamus (LH) did not affect food intake and body weight during regular diet, despite the presence of MC receptors in this region. However, during exposure to a high-fat diet, animals with Agouti expression in the LH exhibited a marked increase in body weight. Here we show that the LH is important for the protection against diet-induced obesity by controlling caloric intake during consumption of a high-fat diet. Together, this study provides evidence that different aspects of the Agouti-induced obesity syndrome, such as hyperphagia and diet responsiveness, are mediated by distinct brain regions and opens challenging opportunities for further understanding of pathophysiological processes in the development of the obesity syndrome.
M2Muscarinic Acetylcholine Receptor Knock-Out Mice Show Deficits in Behavioral Flexibility, Working Memory, and Hippocampal Plasticity
Authors: Seeger Thomas , Fedorova Irina , Zheng Fang , Miyakawa Tsuyoshi , Koustova Elena , Gomeza Jesus , Basile Anthony S. , Alzheimer Christian , Wess Jürgen
Published: November 2004

Muscarinic acetylcholine receptors are known to play key roles in facilitating cognitive processes. However, the specific roles of the individual muscarinic receptor subtypes (M1-M5) in learning and memory are not well understood at present. In the present study, we used wild-type (M2+/+) and M2receptor-deficient (M2-/-) mice to examine the potential role of M2receptors in learning and memory and hippocampal synaptic plasticity. M2-/-mice showed significant deficits in behavioral flexibility and working memory in the Barnes circular maze and the T-maze delayed alternation tests, respectively. The behavioral deficits of M2-/-mice were associated with profound changes in neuronal plasticity studied at the Schaffer-CA1 synapse of hippocampal slices. Strikingly, short-term potentiation (STP) was abolished, and long-term potentiation (LTP) was drastically reduced after high-frequency stimulation of M2-/-hippocampi. Treatment of M2-/-hippocampal slices with the GABAAreceptor antagonist, bicuculline, restored STP and significantly increased LTP. Whole-cell recordings from CA1 pyramidal cells demonstrated a much stronger disinhibition of GABAergic than glutamatergic transmission in M2-/-hippocampi, which was particularly prominent during stimulus trains. Increased strength of GABAergic inhibition is thus a likely mechanism underlying the impaired synaptic plasticity observed with M2-/-hippocampi. Moreover, the persistent enhancement of excitatory synaptic transmission in CA1 pyramidal cells induced by the transient application of a low concentration of a muscarinic agonist (referred to as LTPm) was totally abolished in M2-/-mice. Because impaired muscarinic cholinergic neurotransmission is associated with Alzheimer's disease and normal aging processes, these findings should be of considerable therapeutic relevance.
Highly Efficient Small Interfering RNA Delivery to Primary Mammalian Neurons Induces MicroRNA-Like Effects before mRNA Degradation
Authors: Davidson Thomas J. , Harel Sivan , Arboleda Valerie A. , Prunell Giselle F. , Shelanski Michael L. , Greene Lloyd A. , Troy Carol M.
Published: November 2004

The study of protein function in neurons has been hindered by the lack of highly efficient, nontoxic methods of inducing RNA interference in such cells. Here we show that application of synthetic small interfering RNA (siRNA) linked to the vector peptide Penetratin1 results in rapid, highly efficient uptake of siRNA by entire populations of cultured primary mammalian hippocampal and sympathetic neurons. This treatment leads to specific knock-down of targeted proteins within hours without the toxicity associated with transfection. In contrast to current methods, our technique permits study of protein function across entire populations with minimal disturbance of complex cellular networks. Using this technique, we found that protein knock-down (evident after 6 hr) precedes any decrease in targeted message (evident after 24 hr), suggesting an early, translational repression by perfectly targeted siRNAs.
Culturally Appropriate Family Assessment: Analysis of the Family Assessment Device in a Pediatric Chinese Population
Authors: Chen Jyu-Lin , Kennedy Christine , Kools Susan , Slaughter Robert E. , Franck Linda , Kong Sarah K. F. , Wong Thomas K. S.
Published: November 2004

As part of a larger study, we investigated the adaptation of the Family Assessment Device (FAD) to a Chinese population of hospitalized children (N= 313) compared to a sample of families with healthy children (N =29) in Hong Kong and Chinese Mainland. Confirmatory factor analysis and exploratory factor analysis (EFA) were performed to examine the FAD structure. The results supported the notion of cultural variations in measuring family functioning. Eight factors were found to explain 30.34% of the variance in family functioning. The Cronbach’s alphas of families with hospitalized children ranged from 0.29 to 0.74. Similar reliability scores were found in nonhospitalized families. This study indicates that the Chinese FAD has a different factor structure, reliabilities, and mean scores in several subscales compared to U.S. studies. The psychometric properties of the Chinese FAD may be influenced by the fact that the sample was focused on children rather than adults.
From nest to nest—influence of ecology and reproduction on the active period of adult Gombe chimpanzees
Authors: Lodwick Jessica L. , Borries Carola , Pusey Anne E. , Goodall Jane , McGrew William C.
Published: November 2004

The time spent between sleeping periods, which is called the active period, has to accommodate all essential activities, including feeding, resting, social behavior, and reproduction. To minimize costs in terms of, e.g., predation risk, suboptimal foraging, or sleep deficiency, the active period of diurnal animals should be less than or equal to the daylight period. Thus, the active period of an animal should be shaped by local environmental conditions as well as by metabolic and reproductive demands. Chimpanzees, which exhibit reduced predator pressure and a flexible fission‐fusion society, were chosen as a model to explore these links. We investigated the influence of sex, female reproductive status, dominance rank, and season on the duration of the active period of adult chimpanzees at Gombe National Park, Tanzania (1975–1992). Sexually nonreceptive females had shorter active periods compared to males, while receptive females had even longer active periods than males. Dominance rank did not influence the duration of the active period of nonreceptive females, but high‐ and middle‐ranking males had shorter active periods compared to low‐ranking males. Nonreceptive females exhibited longer active periods during the dry season than in the wet season. No seasonal effect was discovered for males, perhaps because they already had long active periods in the wet season. Nonreceptive females seem to be able to accommodate all essential activities in the daylight period available, probably because they live less socially than males. Thus, the active period does not reflect differences in female competitive abilities, but does reflect such differences in males. The duration of the active period appears to be a simple, reliable tool for exploring basic responses and constraints in animal societies. Am. J. Primatol. 64:249–260, 2004. © 2004 Wiley‐Liss, Inc.
Isolation and identification of fungi from vaginal flora in three species of captive Leontopithecus
Authors: Moraes Ismar A. , Stussi Jussara S.P. , Lilenbaum Walter , Pissinatti Alcides , Luz Fabio P. , Ferreira Ana Maria R.
Published: November 2004

The ability to reproduce in captivity is an essential component of lion tamarin (Leontopithecus) conservation programs. However, infections such as vaginitis, cervicitis, and endometritis are important diseases that may influence the reproduction of these animals. Therefore, it is important to detect continuous or occasional vaginal microbial populations, and to understand their potential role as an endogenous source of infection [Collins, 1964; Blue, 1983; Pugh et al., 1986]. Vaginal swabs were collected from 25 female tamarins of the three currently available species (L. rosalia, L. chrysopygus, and L. chrysomelas) at the Center of Primatology in Rio de Janeiro, Brazil. The swabs were processed according to standard mycological protocols, and isolates were biochemically characterized. Fungal isolates were recovered from 16 animals (64.0%). The results showed that 70.6% of the isolated microorganisms consisted of yeast, including three species of Candida (mainly C. glabrata). We suggest that this species is a resident member of the normal vaginal flora in Leontopithecus. Filamentous fungi (mainly from Trichosporon, Aspergillus, and Penicilliumgenera) constituted 29.4% of the isolates, and were considered to be transitory contaminants of the genital area. We suggest that colonization of the vaginal environment is related to the endocrine pattern associated with the reproductive status of these animals, but not to parity. Am. J. Primatol. 64:337–343, 2004. © 2004 Wiley‐Liss, Inc.
Investigating the nonlinear viscoelastic behavior of rubber materials through Fourier transform rheometry
Authors: Leblanc Jean L.
Published: November 2004

Fourier transform rheometry was used to investigate the nonlinear viscoelastic behavior of a series of gum polybutadiene and styrene–butadiene rubbers. A commercial torsional rheometer [the rubber process analyzer (RPA®, Alpha Technologies)] was suitably modified for capturing strain an torque signals, using appropriate software developed in Lab View® (National Instruments). Proprietary programs, written in MathCad® (MathSoft Inc.), were used to perform Fourier transform (FT) calculations and other data treatments. Results showed that FT rheometry provides not only the same information as standard dynamic testing in the linear region, although with a better accuracy, but gives valuable information about the nonlinear behavior of materials. Using a four‐parameter equation to model the variation of the relative 3rd‐harmonic component with strain amplitude, it was found that the strain sensitivity of the materials was adequately quantified, with results apparently consistent with their processing shear sensitivity. The only material parameters that were found to significantly affect the strain sensitivity are the chemical nature of the elastomers (i.e., polybutadiene versus styrene–butadiene rubber) and the molecular weight. No clear effect of the microstructure was seen, however, likely because the sampling was not discriminating enough in this respect. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 90–106, 2005
Friction of short‐fiber–reinforced rubber on wet surfaces
Authors: Uchiyama Yoshitaka , Wada Noriaki , Iwai Tomoaki , Ueda Seiichi , Sado Shinji
Published: November 2004

The friction coefficient of short‐fiber–reinforced rubber (SFRR) was examined under dry and wet conditions. When the unfilled rubber is rubbed against a dry glass disk, the friction coefficient is higher than that of the SFRR and decreases as contact pressure increases. On the other hand, the friction coefficient for the SFRR is relatively low, and decreases slightly with the increase of contact pressure. When the unfilled rubber is rubbed against a silicone oil–lubricated glass disk, the friction coefficient is lower than that in a dry condition, and decreases with increasing sliding speed to reach a minimum value. After that, it increases slightly with the increment of the sliding speed at the sliding speed range examined. The friction coefficient of the SFRR on the wet surfaces is lower than that of the unfilled rubber at low sliding speeds. With an increase in speed, the friction coefficient initially decreases, and then reaches a minimum value. After that, it increases with the increment of sliding speed. The minimum for the unfilled rubber and the SFRRs shifts toward lower sliding speeds when the contact pressure is increased. Therefore, under the condition of mixed lubrication at low speeds, the friction coefficient at low contact pressure is higher than that at high contact pressure. This trend is distinguishable as the fiber content of the SFRR is increased. The phenomena at high contact pressures arise from the reduction of effective surface roughness, as the unfilled rubber deforms and the SFRRs deflect because of the applied load. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 82–89, 2005
Effects of rubber/filler interactions on the structural development and mechanical properties of NBR/silica composites
Authors: Suzuki Nozomu , Ito Masayoshi , Ono Shigeyuki
Published: November 2004

A study was carried out on the effects of interactions between nitrile–butadiene rubber (NBR) and silica on the developments of agglomerates by silica particles and of bound rubber in NBR/silica composites. The mechanical properties of the composites were also investigated in relation to the structure development. Transmission infrared spectra revealed the existence of hydrogen bonding between nitrile groups in NBR and silanol groups on the silica surface. The number of hydrogen bonds increased with the increasing nitrile group content of NBR. Transmission electron microscopy observations and thermal analysis revealed that the averaged size of agglomerates in composites decreased, and simultaneously the amount of filler–gel in silica‐filled NBR decreased with increasing nitrile group content of NBR. These results suggest that the hydrogen bonding between nitrile groups and silanol groups suppresses the development of agglomerates by silica particles, that is, the dispersion of silica is improved by the hydrogen bonding. At a given nitrile group content of NBR, the storage modulus and the initial slope of stress–strain curves for vulcanized composites increased with increasing the amount of filler–gel. Further, at a larger strain, the composites showed a clear pseudo‐yielding point on the stress–strain curves, with this tendency more prominent in the larger agglomerate size. These results suggest that the mechanical properties for NBR/silica composites are affected by the content of filler–gel. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 74–81, 2005
Effect of Mount Pinatubo volcanic ash on the mechanical properties of styrene–butadiene rubber vulcanizates
Authors: Bedia Elinor L. , Kasai Yutaka , Ikeda Yuko , Kohjiya Shinzo
Published: November 2004

Mt. Pinatubo volcanic ash, collected from Porac, Pampanga, was screened at 32 mesh screen, wet‐ground in a pot mill for 3, 5, and 7 days, and dried. The volcanic ash was characterized and compounded with styrene–butadiene rubber (SBR) vulcanizates. Mineralogical investigation of the volcanic ash showed the presence of feldspar, homblende, quartz, mica, and magnetite. The particle size of the volcanic ash ground for 3, 5, and 7 days ranged from 1440 to 4, 720 to 2, and 640 to 2 μm, respectively. The addition of volcanic ash did not significantly influence the mechanical strength of the SBR vulcanizates. Stress–strain curves of the volcanic ash–filled SBR vulcanizates showed a slight increase from that of the pure gum. As the particle size of the volcanic ash decreased, the tensile strength and elongation at break points increased. Crosslinking sites also increased with the addition of rubber. Furthermore, it was noted that the addition of diethylene glycol hastened the curing reaction without affecting the mechanical properties of SBR vulcanizates. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 68–73, 2005
Chemical modification of polydienes in latex medium: Study of epoxidation and ring opening of oxiranes
Authors: Derouet Daniel , Mulder‐Houdayer Stéphanie , Brosse Jean‐Claude
Published: November 2004

Referring to previous work carried out in organic solvents, a study of the action of nucleophilic reagents on epoxidized units of 1,4‐epoxidized polyisoprene (synthetic polyisoprene or natural rubber) was performed in latex medium. Among the considered reagents, dialkylphosphate and ammonium diethyldithiophosphate demonstrated the ability to add under these reaction conditions on epoxidized units according to a SN2 substitution with an oxirane ring‐opening mechanism. A systematic study was performed with dibutylphosphate that was shown to be very reactive. Grafting of phosphorated groups along polyisoprene chains was carried out via reaction of the acidic function (P‐OH) of the phosphate with oxirane rings previously created on a 1,4‐polyisoprene backbone. The prominent role of latex pH on the reaction was shown. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 39–52, 2005
Differential expression of estrogen receptors (ERα/ERβ) in testis of mature and immature pigs
Authors: Rago Vittoria , Maggiolini Marcello , Vivacqua Adele , Palma Antonio , Carpino Amalia
Published: November 2004

High affinity estrogen receptors (ERs) mediate estrogen action in male reproductive tissues. The objective of the present study was the immunolocalization of estrogen receptor α and estrogen receptor β in immature and mature testes of pig, a species in which the role of estrogens on gonadal function is scarcely known. Testes from 3 and 18 month‐old pigs were investigated. Immunohistochemistry was performed on paraffin embedded‐tissues using both mouse anti‐human monoclonal IgG ERα and IgG ERβ 1 isoform. Western blot analysis demonstrated antibody specificity. ERα staining was not observed in immature testes, but it was detected in spermatogonia, spermatocytes and in the most Leydig cells of mature testes. ERβ immunoreactivity was observed in spermatogonia and Leydig cells of immature gonads, while it was clearly detected in spermatogonia and in spermatocytes of adult pig testes. The differential ERα/ERβ expression in germ and somatic cells of the gonads suggest a role of estrogens in function and in development of pig testis. © 2004 Wiley‐Liss, Inc.
Scholarly use of internet‐based electronic resources
Authors: Zhang Yin
Published: November 2004

This research examines the use of Internet‐based electronic resources (e‐sources) by a group of library and information science (LIS) scholars. It focuses particularly on how scholars use, cite, and evaluate e‐sources during the research process. This research also explores the problems scholars encounter and concerns they have when using e‐sources for research. The following approaches were used to collect data for the investigation: (a) a longitudinal analysis of e‐source citations in eight LIS journals from 1991 through 1998; (b) a survey of editors of the eight journals; and (c) a survey of 201 authors with articles to be published in the eight journals. The longitudinal analysis of e‐source citations shows that there has been a notable increase in the number and proportion of authors who cite e‐sources in their research articles over the 8‐year period, although at the time of this study, e‐sources were still cited much less frequently than print sources. This result provides empirical evidence that e‐sources are increasingly used among scholars. Complementing the citation data, the results from the author survey show that e‐sources are becoming an important component in scholars' research, and are serving a wide range of purposes and functions. The number of access points and self‐perceived overall ability to use the Internet are identified as the two significant variables affecting frequency of e‐source use. The results of this study also suggest that a limited number of criteria can be implemented in practice for scholars to evaluate electronic sources and systems. When citing e‐sources, scholars consider some factors that are unique to e‐sources, in addition to the factors they consider for print sources. Although the advantages of e‐sources promote citing, some drawbacks of e‐sources at this stage serve as a barrier. The survey of editors also reveals a lack of clearly stated editorial policies regarding citing e‐sources. The major problems and concerns reported by scholars regarding using e‐sources are summarized, and both the theoretical implications and practical applications of the findings are discussed.
FEATURES: Real‐time adaptive feature and document learning for web search
Authors: Chen Zhixiang , Meng Xiannong , Fowler Richard H. , Zhu Binhai
Published: November 2004

In this article we report our research on building FEATURES—an intelligent web search engine that is able to perform real‐time adaptive feature (i.e., keyword) and document learning. Not only does FEATURES learn from the user's document relevance feedback, but it also automatically extracts and suggests indexing keywords relevant to a search query and learns from the user's keyword relevance feedback so that it is able to speed up its search process and to enhance its search performance. We design two efficient and mutual‐benefiting learning algorithms that work concurrently, one for feature learning and the other for document learning. FEATURES employs these algorithms together with an internal index database and a real‐time meta‐searcher to perform adaptive real‐time learning to find desired documents with as little relevance feedback from the user as possible. The architecture and performance of FEATURES are also discussed.
Analysis of publications and citations from a geophysics research institute
Authors: Frohlich Cliff , Resler Lynn
Published: November 2004

We here perform an analysis of all 1128 publications produced by scientists during their employment at the University of Texas Institute for Geophysics, a geophysical research laboratory founded in 1972 that currently employs 23 Ph.D.‐level scientists. We thus assess research performance using as bibliometric indicators such statistics as publications per year, citations per paper, and cited half‐lives. To characterize the research style of individual scientists and to obtain insight into the origin of certain publication‐counting discrepancies, we classified the 1128 publications into four categories that differed significantly with respect to statistics such as lifetime citation rates, fraction of papers never‐cited after 10 years, and cited half‐life. The categories were: mainstream (prestige journal) publications—32.6 lifetime cit/pap, 2.4% never cited, and 6.9 year half‐life; archival (other refereed)—12.0 lifetime cit/pap. 21.5% never cited, and 9.5 years half‐life; articles published as proceedings of conferences—5.4 lifetime cit/pap, 26.6% never cited, and 5.4 years half‐life; and “other” publications (news articles, book reviews, etc.)—4.2 lifetime cit/pap, 57.1% never cited, and 1.9 years half‐life. Because determining cited half‐lives is highly similar to a well‐studied phenomenon in earthquake seismology, which was familiar to us, we thoroughly evaluate five different methods for determining the cited half‐life and discuss the robustness and limitations of the various methods. Unfortunately, even when data are numerous the various methods often obtain very different values for the half‐life. Our preferred method determines half‐life from the ratio of citations appearing in back‐to‐back 5‐year periods. We also evaluate the reliability of the citation count data used for these kinds of analysis and conclude that citation count data are often imprecise. All observations suggest that reported differences in cited half‐lives must be quite large to be significant.
Google's web page ranking applied to different topological web graph structures
Authors: Meghabghab George
Published: November 2004

This research is part of the ongoing study to better understand web page ranking on the web. It looks at a web page as a graph structure or a web graph, and tries to classify different web graphs in the new coordinate space: (out‐degree, in‐degree). The out‐degree coordinate od is defined as the number of outgoing web pages from a given web page. The in‐degree id coordinate is the number of web pages that point to a given web page. In this new coordinate space a metric is built to classify how close or far different web graphs are. Google's web ranking algorithm (Brin & Page, 1998) on ranking web pages is applied in this new coordinate space. The results of the algorithm has been modified to fit different topological web graph structures. Also the algorithm was not successful in the case of general web graphs and new ranking web algorithms have to be considered. This study does not look at enhancing web ranking by adding any contextual information. It only considers web links as a source to web page ranking. The author believes that understanding the underlying web page as a graph will help design better ranking web algorithms, enhance retrieval and web performance, and recommends using graphs as a part of visual aid for browsing engine designers.
Totality and representation: A history of knowledge management through European documentation, critical modernity, and post‐Fordism
Authors: Day Ronald E.
Published: November 2004

This article presents European documentalist, critical modernist, and Autonomous Marxist influenced post‐Fordist views regarding the management of knowledge in mid‐ and late twentieth century Western modernity and postmodernity, and the complex theoretical and ideological debates, especially concerning issues of language and community. The introduction and use for corporate, governmental, and social purposes of powerful information and communication technologies created conceptual and political tensions and theoretical debates. In this article, knowledge management, including the specific recent approach known as “Knowledge Management,” is discussed as a social, cultural, political, and organizational issue, including the problematic feasibility of capturing and representing knowledge that is “tacit,” “invisible,” and is imperfectly representable. “Social capital” and “affective labor” are discussed as elements of “tacit” knowledge. Views of writers in the European documentalist, critical modernist, and Italian Autonomous Marxist influenced post‐Fordist traditions, such as Otlet, Briet, Heidegger, Benjamin, Marazzi, and Negri, are discussed.1
Toward automatic Chinese temporal information extraction
Authors: Li Wenjie , Wong Kam‐Fai , Yuan Chunfa
Published: November 2004

Over the past few years, temporal information processing and temporal database management have increasingly become hot topics. Nevertheless, only a few researchers have investigated these areas in the Chinese language. This lays down the objective of our research: to exploit Chinese language processing techniques for temporal information extraction and concept reasoning. In this article, we first study the mechanism for expressing time in Chinese. On the basis of the study, we then design a general frame structure for maintaining the extracted temporal concepts and propose a system for extracting time‐dependent information from Hong Kong financial news. In the system, temporal knowledge is represented by different types of temporal concepts (TTC) and different temporal relations, including absolute and relative relations, which are used to correlate between action times and reference times. In analyzing a sentence, the algorithm first determines the situation related to the verb. This in turn will identify the type of temporal concept associated with the verb. After that, the relevant temporal information is extracted and the temporal relations are derived. These relations link relevant concept frames together in chronological order, which in turn provide the knowledge to fulfill users' queries, e.g., for question‐answering (i.e., Q&A) applications.
Information discovery from complementary literatures: Categorizing viruses as potential weapons
Authors: Swanson Don R. , Smalheiser Neil R. , Bookstein A.
Published: November 2004

Using novel informatics techniques to process the output of Medline searches, we have generated a list of viruses that may have the potential for development as weapons. Our findings are intended as a guide to the virus literature to support further studies that might then lead to appropriate defense and public health measures. This article stresses methods that are more generally relevant to information science. Initial Medline searches identified two kinds of virus literatures—the first concerning the genetic aspects of virulence, and the second concerning the transmission of viral diseases. Both literatures taken together are of central importance in identifying research relevant to the development of biological weapons. Yet, the two literatures had very few articles in common. We downloaded the Medline records for each of the two literatures and used a computer to extract all virus terms common to both. The fact that the resulting virus list includes most of an earlier independently published list of viruses considered by military experts to have the highest threat as potential biological weapons served as a test of the method; the test outcome showed a high degree of statistical significance, thus supporting an inference that the new viruses on the list share certain important characteristics with viruses of known biological warfare interest.
A unified maximum likelihood approach to document retrieval
Authors: Bodoff David , Enache Daniel , Kambil Ajit , Simon Gary , Yukhimets Alex
Published: November 2004

Empirical work shows significant benefits from using relevance feedback data to improve information retrieval (IR) performance. Still, one fundamental difficulty has limited the ability to fully exploit this valuable data. The problem is that it is not clear whether the relevance feedback data should be used to train the system about what the users really mean, or about what the documents really mean. In this paper, we resolve the question using a maximum likelihood framework. We show how all the available data can be used to simultaneously estimate both documents and queries in proportions that are optimal in a maximum likelihood sense. The resulting algorithm is directly applicable to many approaches to IR, and the unified framework can help explain previously reported results as well as guide the search for new methods that utilize feedback data in IR.
Content based image retrieval and information theory: A general approach
Authors: Zachary John , Iyengar S. S. , Barhen Jacob
Published: November 2004

A fundamental aspect of content‐based image retrieval (CBIR) is the extraction and the representation of a visual feature that is an effective discriminant between pairs of images. Among the many visual features that have been studied, the distribution of color pixels in an image is the most common visual feature studied. The standard representation of color for content‐based indexing in image databases is the color histogram. Vector‐based distance functions are used to compute the similarity between two images as the distance between points in the color histogram space. This paper proposes an alternative real valued representation of color based on the information theoretic concept of entropy. A theoretical presentation of image entropy is accompanied by a practical description of the merits and limitations of image entropy compared to color histograms. Specifically, the L1norm for color histograms is shown to provide an upper bound on the difference between image entropy values. Our initial results suggest that image entropy is a promising approach to image description and representation.
Information theoretic similarity measures for content based image retrieval
Authors: Zachary John , Iyengar S. S.
Published: November 2004

Content‐based image retrieval is based on the idea of extracting visual features from image and using them to index images in a database. The comparisons that determine similarity between images depend on the representations of the features and the definition of appropriate distance function. Most of the research literature uses vectors as the predominate representation given the rich theory of vector spaces. While vectors are an extremely useful representation, their use in large databases may be prohibitive given their usually large dimensions and similarity functions. In this paper, we propose similarity measures and an indexing algorithm based on information theory that permits an image to be represented as a single number. When use in conjunction with vectors, our method displays improved efficiency when querying large databases.
Flow injection chemiluminescence determination of dihydralazine sulphate based on permanganate oxidation sensitized by rhodamine B
Authors: Yang Xiao‐Feng , Wu Dong‐Bing , Li Hua
Published: November 2004

A novel ﬂow injection chemiluminescence (CL) method for the determination of dihydralazine sulphate (DHZS) is described. The method is based on the CL produced during the oxidation of DHZS by acidic permanganate solution in the presence of rhodamine B. Rhodamine B is suggested as a ﬂuorescing compound for the energy‐transferred excitation. The CL emission allows quantitation of DHZS concentration in the range 5–800 ng/mL, with a detection limit of 1.9 ng/mL (3σ). The experimental conditions for the CL reaction are optimized and the possible reaction mechanism is discussed. The method has been applied to the determination of DHZS in pharmaceutical preparations and compares well with the high performance liquid chromatography (HPLC) method. Copyright © 2004 John Wiley & Sons, Ltd.