bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of heat treatment on bioactivities of enamel matrix derivatives in human periodontal ligament (HPDL) cells
Authors: Nagano Takatoshi , Iwata Takanori , Ogata Yorimasa , Tanabe Takako , Gomi Kazuhiro , Fukae Makoto , Arai Takashi , Oida Shinichiro
Published: June 2004

Objectives:  It has been shown that Emdogain® (EMD) containing enamel matrix derivative has cementum‐ and osteo‐promotive activities in vivo and in vitro. Nevertheless, the commercial sale of EMD was halted because it has some possible risk for infectiosity. At present, Emdogain® Gel (Emd‐Gel) containing the EMD heated to avoid the infectiosity is commercially available. The purpose of this study was to compare the in vitro bioactivities of Emd‐Gel and EMD.

Material and methods:  Healthy human periodontal ligament (HPDL) cells were used to study the effect of Emd‐Gel and EMD on cell differentiation. The HPDL cells exposed to Emd‐Gel and EMD were evaluated for the following effects: (i) alkaline phosphatase (ALP) activity; (ii) mitogenic (MTT) assay; (iii) biomineralization activity; (iv) gene expressions using reverse transcription‐polymerase chain reaction (RT‐PCR). The effect of EMD with or without heat treatment was examined for ALP activity on the cell differentiation.

Results:  The effect of Emd‐Gel on ALP activity was greater than that of EMD. It was confirmed from the effect of EMD with heat treatment at 60°C, 80°C and 100°C on the ALP activity. The effect of Emd‐Gel on the biomineralization activity was also greater than that of the EMD. The Emd‐Gel has a stronger effect for the expression of osteoblast‐like phenotype than the EMD.

Conclusion:  The results indicate that the Emd‐Gel has greater bioactivities than the EMD in vitro.
Effects of long‐term cyclosporin therapy on the periodontium of rats
Authors: Spolidorio L. C. , Spolidorio D. M. , Holzhausen M.
Published: June 2004

Background:  The treatment of cyclosporin A triggers an early bone loss and gingival overgrowth. There is a lack of studies exploring the effects of long‐term cyclosporin A therapy on alveolar bone homeostasis and gingival tissue.

Objective:  The purpose of this study was to evaluate the effects of long‐term therapy with cyclosporin A on the gingival tissue and on the alveolar bone metabolism in rats.

Materials and methods:  Rats were treated for 60, 120, 180 and 240 days with a daily subcutaneous injection of 10 mg/kg body weight of cyclosporin A. At the end of experimental periods, animals were killed and the serum calcium (Ca2+) and alkaline phosphatase levels were measured in all groups. After histological processing, the oral epithelium and the connective tissue, as well as volume densities of alveolar bone (Vb) and multinucleated osteoclasts (Vo), were assessed at the region of the lower first molars.

Results:  Significant increases in the serum alkaline phosphatase were observed in those groups that received cyclosporin A therapy. After 60 and 120 days of the treatment with cyclosporin A, evident gingival overgrowth associated with a significant increase of epithelium and connective tissue was observed, as well as a decrease of the densities of bone and an increase of densities of osteoclasts. After 180 and 240 days of the treatment, there was a reduction of the gingival overgrowth associated with significant decreases of epithelium and connective tissue, as well as an increase of bone densities and a decrease of osteoclasts.

Conclusion:  Within the limits of this experimental study, it can be concluded that the deleterious periodontal effects of cyclosporin A administration may be time‐related side‐effects.
Antibody reactive with Porphyromonas gingivalis hemagglutinin in chronic and generalized aggressive periodontitis
Authors: Califano Joseph V. , Chou Debra , Lewis Janina P. , Rogers Jeffrey D. , Best Al M. , Schenkein Harvey A.
Published: June 2004

Background:  Porphyromonas gingivalis, a black‐pigmented, gram‐negative anaerobe, is found in periodontitis lesions and its presence in subgingival plaque significantly increases the risk for periodontitis. We have previously shown that patients with aggressive forms of periodontitis that are seropositive for P. gingivalis have less attachment loss than those that are seronegative. This suggests that antibody reactive with antigens of P. gingivalis may be protective and decrease disease severity and extent. Recent studies in the murine abscess model and in the host antibody response in chronic periodontitis patients suggest that antibody reactive with P. gingivalis hemagglutinin may be an important protective antibody response.

Objectives:  In this study, we tested the hypothesis that there was a significant relationship between antibody reactive with P. gingivalis hemagglutinin and measures of periodontal attachment loss.

Methods:  We determined the immunoglobulin G (IgG) antibody concentration reactive with recombinant P. gingivalis hemagglutinin in 117 chronic periodontitis and 90 generalized aggressive periodontitis patients. We also determined the IgG subclass distribution for antibody reactive with P. gingivalis hemagglutinin.

Results and Conclusions:  We found IgG reactive with P. gingivalis hemagglutinin in both chronic periodontitis and generalized aggressive periodontitis patients. Most of this IgG antibody was of the IgG1 and IgG3 subclasses. Antibody reactive with P. gingivalis hemagglutinin, however, did not have a significant relationship with measures of periodontal attachment loss.
Potential applications of Erbium:YAG laser in periodontics
Authors: Ishikawa Isao , Aoki Akira , Takasaki Aristeo Atsushi
Published: June 2004

Objectives:  Since lasers were introduced for the treatment of oral diseases, there has been considerable advancement in technology. As a result, numerous laser systems are currently available for oral use. Neodymium:Yttrium–Aluminum:Garnet (Nd:YAG), carbon dioxide (CO2) laser and the semiconductor Diode lasers have already been approved by the US Food and Drug Administration for soft tissue treatment in oral cavity. The Erbium:YAG (Er:YAG) laser was approved in 1997 for hard tissue treatment in dentistry and recent studies have reported positive results. This suggests that the Er:YAG laser system is a promising apparatus, which will be able to revolutionize and improve dental practice, in particular periodontal treatment. In this mini‐review, we would like to describe the positive characteristics of the Er:YAG laser which indicate its potential as a new treatment modality in periodontics.

Materials and methods:  Recent findings are summarized briefly to evaluate the potential of the Er:YAG laser for clinical application in periodontics.

Results:  The Er:YAG laser possesses suitable characteristics for oral soft and hard tissue ablation. Recently, it has been applied for effective elimination of granulation tissue, gingival melanin pigmentation and gingival discoloration. Contouring and cutting of bone with minimal damage and even or faster healing can also be performed with this laser. In addition, irradiation with the Er:YAG laser has a bactericidal effect with reduction of lipopolysaccharide, high ability of plaque and calculus removal, with the effect limited to a very thin layer of the surface and is effective for implant maintenance.

Conclusion:  The Er:YAG laser seems to be an effective tool for periodontal therapy, however, further clinical and basic investigations are required to confirm its clinical application.
Influence of the matrix metalloproteinase inhibitor batimastat (BB‐94) on periodontal bone destruction in Sprague‐Dawley rats
Authors: Björnsson Magnús Jón , Havemose‐Poulsen Anne , Stoltze Kaj , Holmstrup Palle
Published: June 2004

Background: Matrix metalloproteinases (MMPs) are proteolytic enzymes capable of degrading most macromolecules of the extracellular matrix. It has been assumed that an association exists between MMP activity and periodontal disease progression, but the precise role of MMPs in disease progression is still not fully clarified. Batimastat, or BB‐94, is a synthetic broad‐spectrum MMP inhibitor not previously examined in periodontal research. If there is an association between MMP activity and periodontal disease progression, then batimastat might be expected to reduce the progression of experimental periodontal disease in rats.

Objectives: The objective of the present study was to determine the effects of batimastat on periodontal status in healthy Sprague‐Dawley (SPRD) rats as well as in rats with ligature‐induced experimental periodontal disease.

Methods and Results: Periodontal bone destruction was used as a means of evaluating periodontal destruction by measuring periodontal bone loss on defleshed rat jaws and periodontal bone support on radiographs of the jaws. There was significantly more periodontal bone destruction in the groups treated with batimastat than in the placebo and control groups. This accounted for both ligated and non‐ligated groups, irrespective of whether periodontal bone loss (p < 0.05) or periodontal bone support (p < 0.05) were measured.

Conclusion: In conclusion, the results of this study did not support the hypothesis that the MMP inhibitor batimastat could reduce the progression of experimental periodontal disease in rats. Instead, significantly increased bone destruction was found in rats treated with batimastat.
Mifepristone (Ru486) Antagonizes Monocyte Chemotactic Protein‐3 Down‐Regulation at Early Mouse Pregnancy Revealing Immunomodulatory Events in Ru486 Induced Abortion
Authors: Nautiyal Jaya , Kumar Pradeep G. , Laloraya Malini
Published: June 2004

Problem:  The survival of an embryo bearing the paternal antigens within the immunocompetent environment of the maternal uterus renders ‘pregnancy’ to be a state of immunological paradox. The ratio of Th1/Th2 responses is crucial for pregnancy maintenance. Monocyte Chemotactic Protein‐3 (MCP3) is a pro‐inflammatory, CC chemokine and a Th1 effector which is capable of eliciting significant anti‐tumoral immune responses.

Method of study:  MCP3 expression was investigated in the murine uterine tissue at different days of initial pregnancy and the effect of RU 486 in immature and delayed implantation model studied using Western blotting and Immunocytochemical techniques.

Results and conclusion:  Our results show very high uterine MCP3 expression during pre‐implantation followed by a significant MCP3 down‐regulation at peri‐implantation and low levels of MCP3 during post‐implantation period. At the peri‐implantation stage, embryos exhibited lowered MCP3 expression when compared with the pre‐implantation stage. Ru486, a progesterone antagonist when given in a competitive mode with progesterone resulted in a massive surge in MCP3 expression in both immature mice and delayed implantation models. We hypothesize that it is imperative for MCP3 expression to be down‐regulated for the success of pregnancy. The cross‐talk between Ru486 and amplified MCP3 expression may be one of the mechanisms by way of which RU486 performs its abortificient and anti tumor role.
Increased Expression of Pro‐Inflammatory Cytokines in Placentas of Women Undergoing Spontaneous Preterm Delivery or Premature Rupture of Membranes
Authors: El‐Shazly Sherief , Makhseed Ma'asoumah , Azizieh Fawaz , Raghupathy Raj
Published: June 2004

Problem:  The objective of this study was to determine the levels of cytokines in the placentas of women undergoing preterm delivery (PTD) or premature rupture of membranes (PROM) as compared with women undergoing normal delivery at term.

Method of study:  Placentas were obtained from 30 subjects with spontaneous PTD, 30 women with PROM and 30 women with a history of normal delivery at term. Levels of interleukin (IL)‐2, interferon (IFN)‐γ, tumor necrosis factor (TNF)‐α, TNF‐β, IL‐4, IL‐5, IL‐6 and IL‐10 and IL‐12 were estimated by ELISA in detergent lysates of placentas from the subjects.

Results:  We found significantly increased levels of the Th1 cytokines IL‐2 and IFNγ and of the Th1‐inducing cytokine IL‐12 in placentas from the PTD and PROM groups as compared with those delivering at term. In contrast, the levels of the Th2 cytokines IL‐4, IL‐6 and IL‐10 were significantly higher in placentas from term pregnancy.

Conclusions:  These data support our observation of a pro‐inflammatory cytokine bias in women with PTD and PROM.
Computational Design of a Biologically Active Enzyme
Authors: Dwyer Mary A. , Looger Loren L. , Hellinga Homme W.
Published: June 2004

Rational design of enzymes is a stringent test of our understanding of protein chemistry and has numerous potential applications. Here, we present and experimentally validate the computational design of enzyme activity in proteins of known structure. We have predicted mutations that introduce triose phosphate isomerase activity into ribose-binding protein, a receptor that normally lacks enzyme activity. The resulting designs contain 18 to 22 mutations, exhibit 10
5
- to 10
6
-fold rate enhancements over the uncatalyzed reaction, and are biologically active, in that they support the growth of
Escherichia coli
under gluconeogenic conditions. The inherent generality of the design method suggests that many enzymes can be designed by this approach.
A Molecular Photodiode System That Can Switch Photocurrent Direction
Authors: Yasutomi Shiro , Morita Tomoyuki , Imanishi Yukio , Kimura Shunsaku
Published: June 2004

We prepared a molecular photodiode system in which the photocurrent direction can be switched by choosing the wavelength of an irradiating light. The molecular system is composed of two types of helical peptides that carry different chromophores and have different directions of dipole moments when they are immobilized on gold. The mixed, self-assembled monolayer generated an anodic photocurrent when one of the two chromophores was photoexcited, whereas the photocurrent switched to being cathodic when the other chromophore was photoexcited. The opposite current response arises from the dipole moment of each helical peptide, which accelerates electron transfer in the same direction.
Mechanistic Diversity of Cytokine Receptor Signaling Across Cell Membranes
Authors: Stroud Robert M. , Wells James A.
Published: June 2004

Circulating cytokines bind to specific receptors on the cell outer surface to evoke responses inside the cell. Binding of cytokines alters the association between receptor molecules that often cross the membrane only once in a single alpha-helical segment. As a consequence, association of protein domains on the inside of the membrane are also altered. Increasing evidence suggests that an initial "off-state" of associated receptors is perturbed, and brought to an activated state that leads to intracellular signaling and eventually effects a change in DNA transcription. The initial detection event that transduces the change in receptor association is sensitive to both proximity and orientation of the receptors, and probably also to the time that the activated state or receptor association is maintained. Ultimately, a cascade of phosphorylation events is triggered. The initial kinases are sometimes part of the intracellular domains of the receptors. The kinases can also be separate proteins that may be pre-associated with intracellular domains of the receptors, or can be recruited after the intracellular association of the activated receptors. We focus here on each of the cases for which structures of the activated cytokine-receptor complexes are known, in a search for underlying mechanisms. The variations in modes of association, stoichiometries of receptors and cytokines, and orientations before and after activation of these receptors are almost as great as the number of complexes themselves. The principles uncovered nevertheless illustrate the basis for high specificity and fidelity in cytokine-mediated signaling.
A Novel In Situ Assay for the Identification and Characterization of Soluble Nuclear Mobility Factors
Authors: Elbi Cem , Walker Dawn A. , Lewis Marcia , Romero Guillermo , Sullivan William P. , Toft David O. , Hager Gordon L. , DeFranco Donald B.
Published: June 2004

The development of green fluorescent protein (GFP) technology combined with live cell microscopy techniques have revealed the dynamic properties of GFP-tagged proteins in the nucleus. The mobility of a GFP-tagged protein can be assessed using a quantitative photobleaching technique, fluorescence recovery after photobleaching (FRAP) analysis. FRAP experiments demonstrate that many nuclear proteins are highly mobile within the nucleus. However, the factors within the nucleus that regulate this mobility are not known. This is partly due to an absence of protocols that can be used to identify such nuclear mobility factors. We developed a novel in situ assay that combines a biochemical permeabilization and extraction procedure with a quantitative FRAP technique, a method we used to uncover a new functional role for molecular chaperones in the nuclear mobility of steroid receptors. This assay can readily be adapted to identify and characterize other nuclear mobility factors.
Occupational magnetic field exposure among women in Stockholm County, Sweden
Authors: Forssén U M , Mezei G , Nise G , Feychting M
Published: June 2004

Background:Most epidemiological studies on adverse health effects among women in relation to occupational magnetic field exposure have been based on information about men’s exposure.

Aims:To create a job-exposure matrix for occupational exposure to extremely low frequency magnetic fields among women.

Methods and Results:Measurements were performed using personal magnetic field meters (Emdex Lite) carried by the subjects for 24 hours on a normal workday. Subjects were volunteer women working in the occupations identified as common among women in Stockholm County based on the 1980 census. A total of 471 measurements were made in 49 different occupations, with a minimum of 5 and a maximum of 24 measurements in each occupation. The included occupations cover about 85% of the female population gainfully employed in 1980. Parameters representing average and peak magnetic field exposures, temporal change in the exposure, and proportion of time spent above certain exposure levels were calculated both for the workday and for the total 24 hour period grouped by occupational titles. The occupations with higher than average exposure were cashiers, working proprietors in retail trade, air stewardesses, dental nurses, cooks, post-office clerks and kitchen maids.

Conclusions:This new job-exposure matrix substantially increases the knowledge about magnetic field exposure among women and can be used for exposure assessment in future studies.
Hepatitis E,Helicobacter pylori, and gastrointestinal symptoms in workers exposed to waste water
Authors: Jeggli S , Steiner D , Joller H , Tschopp A , Steffen R , Hotz P
Published: June 2004

Background:Workers exposed to sewage may have an increased risk of infection byHelicobacter pyloriand hepatitis E virus (HEV).

Aims:To assess the prevalence of clinical hepatitis E (HE) and peptic ulcer disease as well as the seroprevalence of antibodies toH pyloriand HEV in workers with and without sewage exposure and to look for symptoms due to exposure to endotoxin.

Methods:In the first year of a prospective cohort study 349 sewage exposed workers and 429 municipal manual workers (participation: 61%) underwent a complete medical examination. Travelling to endemic areas, socioeconomic level, age, country in which childhood was spent, and number of siblings were considered as the main confounding factors.

Results:Peptic ulcer disease and clinical HE did not occur more often in workers exposed to sewage. Prevalence of antibodies to HEV was 3.3% and overall prevalence of IgG antibodies toH pyloriwas 42% with large differences between subgroups. Logistic regression did not show an increased risk of seropositivity or antibodies to parietal cells in sewage exposed workers, but disentangling the effect of exposure from that of confounders was extremely difficult. No increase of symptoms due to exposure to endotoxin was found in sewage workers, with the exception of diarrhoea.

Conclusions:No clear increased risk of infection byH pylorior by HEV in workers exposed to sewage was found in this cross-sectional study, but these results need to be confirmed by follow up.
Predictors of re-employment and quality of life in NHS staff one year after early retirement because of ill health; a national prospective study
Authors: Pattani S , Constantinovici N , Williams S
Published: June 2004

Aims:To measure changes in health related quality of life and employment status of NHS staff one year after early retirement because of ill health, and to identify predictors of re-employment.

Methods:A national cohort of 1317 NHS staff taking early retirement because of ill health in 1998 was recruited. Postal questionnaires were used to assess their quality of life (SF-36) and employment status 12 months after retirement.

Results:A total of 1143 (87%) ill health retirees responded; 152 (13%) retirees were working at one year, mostly part-time, and 22% of them were re-employed by the NHS. Independent predictors of re-employment were: living in England rather than Wales and occupation of doctor. There was an increased likelihood of re-employment with reducing age and increasing quality of life at baseline. Retirees’ quality of life improved from baseline to one year after ill health retirement, but at one year still remained lower than the general population. Improvements in physical and mental component scores were greater in those working at one year compared with those not working.

Conclusion:Reducing ill health retirement is likely to be of benefit to the individual, the NHS, and the economy. Results suggest that such a reduction may be possible and the identified predictors of re-employment may help in this process.
Mortality of employees of the United Kingdom Atomic Energy Authority, 1946–97
Authors: Atkinson W D , Law D V , Bromley K J , Inskip H M
Published: June 2004

Background:The workforce of the UK Atomic Energy Authority has been the subject of several previous epidemiological investigations.

Aims:To detect and investigate associations between mortality rates and employment in a substantially increased cohort size and follow up extended to 1997.

Methods and Results:The new cohort included 51 367 employees, of whom 10 249 were dead. Mortality rates for all workers were low compared to national rates, as were rates in radiation workers and for workers monitored for internal contamination. For radiation workers all cause mortality and all cancer mortality were significantly lower than for non-radiation workers. There was no overall trend of increasing mortality with radiation dose. There was little evidence of raised mortality from leukaemia. The association of prostatic cancer with radiation dose was much less significant than in previous reports. However, the relatively high mortality from uterine cancers among radiation workers remained, though the numbers were very small. The association was with endometrial rather than cervical cancer. Mortality from cancer of the pleura was high among radiation workers, but was not correlated with dose.

Conclusion:Overall, radiation workers at UKAEA showed no excess mortality. The previously detected association of prostate cancer with high radiation dose may have been a statistical artefact or a risk associated with discontinued activities. Endometrial cancer occurred at higher rates in female radiation workers, but, because there was no correlation with dose, may well be due to something other than their radiation exposure. Cancer of the pleura in radiation workers was almost certainly related to past asbestos exposure.
MVP: a model to simulate the spatial patterns of photosynthetically active radiation under discrete forest canopies
Authors: Song Conghe , Band Lawrence E
Published: June 2004

The spatial patterns of photosynthetically active radiation (PAR) under forest canopies, including both its mean and spatial variation, are critical factors to numerous understory ecophysiological processes. Currently, Beer's law is the primary algorithm used in ecological models simulating PAR transmission through plant canopies, because more accurate models are too complicated to be used operationally. This study developed a simple and computationally efficient model at a stand scale to simulate both the mean and variation of PAR (MVP) under forest canopies. The model assumes that a forest canopy is composed of individual crowns distributed within upper and lower boundaries with two types of gaps: the between- and within-crown gaps. The between-crown gaps are simulated with geometric optics, and the within-crown gaps are described by Beer's law. The model accounts for the covariance of PAR in space through time, making it possible to simulate both instantaneous and daily accumulated variance of PAR. Validation with observed PAR from the boreal ecosystematmosphere study (BOREAS) indicates that the model captures the mean and variance of PAR under forest canopy reasonably well. MVP holds the potential to improve simulation of light interception by forest canopies as well as the treatment of canopy rainfall interception in ecological models.
Characterizing the light environment in Sierra Nevada mixed-conifer forests using a spatially explicit light model
Authors: Gersonde Rolf , Battles John J , O'Hara Kevin L
Published: June 2004

The spatially explicit light model tRAYci was calibrated to conditions in multi-aged Sierra Nevada mixed-conifer forests. To reflect conditions that are important to growth and regeneration of this forest type, we sampled a variety of managed mature stands with multiple canopy layers and cohorts. Calibration of the light model included determining leaf area density for individual species with the use of leaf area  sapwood area prediction equations. Prediction equations differed between species and could be improved using site index. The light model predicted point measurements from hemispherical photographs well over a range of 27%63% light. Simplifying the crown representation in the tRAYci model to average values for species and canopy strata resulted in little reduction in model performance and makes the model more useful to applications with lower sampling intensity. Vertical light profiles in managed mixed-conifer stands could be divided into homogeneous, sigmiodal, and continuous gradients, depending on stand structure and foliage distribution. Concentration of leaf area in the upper canopy concentrates light resources on dominant trees in continuous canopies. Irregular canopies of multiaged stands, however, provide more light resources to mid-size trees and could support growth of shade-intolerant species. Knowledge of the vertical distribution of light intensity in connection with stand structural information can guide regulation of irregular stand structures to meet forest management objectives.
4-Acetyl-12,13-Epoxyl-9-Trichothecene-3,15-Diol from Isaria japonica Mediates Apoptosis of Rat Bladder Carcinoma NBT-II Cells by Decreasing Anti-apoptotic Bcl-2 Expression and Increasing Pro-apoptotic Bax Expression
Authors: Kim Hyung-Jin , Jang Seon Il , Kim Young-Jun , Pae Hyun-Ock , Won Hae-Young , Hong Kyung-Hwan , Oh Hyuncheol , Kwon Tae-Oh , Chung Hun-Taeg
Published: June 2004

We studied the effect of 4-acetyl-12,13-epoxyl-9-trichothecene-3,15-diol (AETD) isolated from Isaria japonica, one of the most popular Chinese fungal medicines, on the induction of apoptosis in rat bladder carcinoma NBT-II cells. AETD was cytotoxic to NBT-II cells, and this cytotoxic effect appears to be attributed to its induction of apoptotic cell death, as AETD induced nuclear morphological changes and internucleosomal DNA fragmentation, and increased the proportion of hypodiploid cells and activity of caspase-3. AETD treatment also decreased the expression of the anti-apoptotic protein Bcl-2 and increased the expression of the pro-apoptotic protein Bax. These results provide important information in understanding the mechanism(s) of AETD-induced apoptosis.
Acupressure and Transcutaneous Electrical Acupoint Stimulation in Improving Fatigue, Sleep Quality and Depression in Hemodialysis Patients
Authors: Tsay Shiow-Luan , Cho Yi-Ching , Chen Mei-li
Published: June 2004

This paper has been withdrawn from AJCM. Please contact ajcm@wspc.com
The Effectiveness of Auriculoacupoint Treatment for Artificially Induced Acute Hepatic Injury in Dogs
Authors: Lee Sang-Eun , Song Kun-Ho , Liu Jianzhu , Kwon Hyun-Ju , Youn Sang-Bo , Lee Young-Won , Cho Sung-Hwan , Kim Duck-Hwan
Published: June 2004

This study was to investigate effects of auriculoacupoint (AAP) treatment on carbon tetrachloride ( CCl 4)-induced acute hepatic injury in ten dogs (four females and six males). Dogs have been divided into two groups: the control group (four dogs), not stimulated after induction of hepatic injury and the experimental group (six dogs), stimulated with AAP and massaged at the affected liver region of internal ear after induction of hepatic injury. Serum enzyme activities and histopathological findings were examined after the application of AAP. Compared to the control group, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in the experimental group were significantly decreased at the 4th day ( p <0.05) and at the 5th day ( p <0.05), respectively. Histopathological findings of the experimental group showed decrease of necrotic region and size of lipid droplets compared to the control group.

In conclusion, AAP treatment had a therapeutic effect on the recovery of liver injury induced by CCl 4 in dogs.
BLOCH OSCILLATIONS OF COLD ATOMS IN OPTICAL LATTICES
Authors: KOLOVSKY ANDREY R. , KORSCH HANS JÜRGEN
Published: June 2004

This work is devoted to Bloch oscillations (BO) of cold neutral atoms in optical lattices. After a general introduction to the phenomenon of BO and its realization in optical lattices, we study different extentions of this problem, which account for recent developments in this field. These are two-dimensional BO, decoherence of BO, and BO in correlated systems. Although these problems are discussed in relation to the system of cold atoms in optical lattices, many of the results are of general validity and can be well applied to other systems showing the phenomenon of BO.
ϕ-MAPPING TOPOLOGICAL THEORY IN TWO-GAP SUPERCONDUCTOR
Authors: DUAN YISHI , SHI XUGUANG
Published: June 2004

In this paper, the topological structure of the two-gap superconductor is discussed in detail based on the ϕ-mapping theory. The expression of the vorticity ∇×V of the composite vortex is given and the relation between the vorticity and the magnetic field which is carried by the composite vortex is discussed. The curl of velocity ∇×V has important relation to δ2(ϕ) or we can say that ∇×V has an important relation to the zero points of ϕ. The inner structure of the topological current is characterized by the ϕ-mapping topological numbers Hopf-index and Brouwer degrees.
REDUCTIONS OF CHERN–SIMONS THEORY RELATED TO INTEGRABLE SYSTEMS WHICH HAVE GEOMETRIC APPLICATIONS
Authors: BRACKEN PAUL
Published: June 2004

The Chern–Simons functional is introduced in terms of chiral fields and then studied here. The current can be regarded as a non-Abelian pure gauge potential so that the zero-curvature equations are of Lagrangian form for pure non-Abelian Chern–Simons theory. The equations of motion are developed and a formalism which connects the zero curvature equations with a related moving trihedral is introduced. The moving frame equations are written down for the system and a correspondence between these equations and several related elementary integrable systems is described in the same formalism as well.
THE ABELIAN INTEGRALS OF A ONE-PARAMETER HAMILTONIAN SYSTEM UNDER CUBIC PERTURBATIONS
Authors: ZHANG TONGHUA , CHEN WENCHENG , ZANG HONG
Published: June 2004

In this paper, a one-parameter Hamiltonian system under cubic perturbations is investigated and the upper bound of the number of zeros of the Abelian integral is obtained by using Horozov and Iliev's method.
PHASE DEPENDENT TRANSITION BETWEEN MULTISTABLE STATES IN A NEURAL NETWORK WITH RECIPROCAL INHIBITION
Authors: TATENO KATSUMI , TOMONARI HIDEYUKI , HAYASHI HATSUO , ISHIZUKA SATORU
Published: June 2004

We studied multistable oscillatory states of a small neural network model and switching of an oscillatory mode. In the present neural network model, two pacemaker neurons are reciprocally inhibited with conduction delay; one pacemaker neuron inhibits the other via an inhibitory nonpacemaker interneuron, and vice versa. The small network model shows bifurcations from quasi-periodic oscillation to chaos via period 3 with increase in the synaptic weight of the reciprocal inhibition. The route to chaos in the network model is different from that in the single pacemaker neuron. The network model exhibits several multistable states. In a regime of a weak inhibitory connection, in-phase beat, out-of-phase beat (period 3), and chaotic oscillation coexist at the multistable state. We can switch an oscillatory mode by an excitatory synaptic input to one of the pacemaker neurons through an afferent path. In a strong inhibitory connection regime, in-phase beat and out-of-phase beat (period 4) coexist at the multistable state. An excitatory synaptic input through the afferent path leads to the transition from the in-phase beat to the out-of-phase beat. The transition from the out-of-phase beat to the in-phase beat is induced by an inhibitory synaptic input via interneurons. A conduction delay, furthermore, causes the spontaneous transition from the in-phase beat to the out-of-phase beat. These transitions can be explained by phase response curves.
AN ANALYTIC PICTURE OF NEURON OSCILLATIONS
Authors: PHILLIPSON PAUL E. , SCHUSTER PETER
Published: June 2004

Current induced oscillations of a space clamped neuron action potential demonstrates a bifurcation scenario originally encapsulated by the four-dimensional Hodgkin–Huxley equations. These oscillations were subsequently described by the two-dimensional FitzHugh–Nagumo Equations in close agreement with the Hodgkin–Huxley theory. It is shown that the FitzHugh–Nagumo equations can to close approximation be reduced to a generalized van der Pol oscillator externally driven by the current. The current functions as an external constant force driving the action potential. As a consequence approximate analytic expressions are derived which predict the bifurcation scenario, the amplitudes of the oscillations and the oscillation periods in terms of the current and the physiological constants of the FitzHugh–Nagumo model. A second reduction permits explicit analytic solution and results in a spiking model which can be multiply coupled and extended to include the dynamics of phase locking, entrainment and chaos characteristic of time-dependent synaptic inputs.
A NEW PHENOMENON IN NONAUTONOMOUS CHUA'S CIRCUITS: GENERATION OF CHAOTIC BEATS
Authors: CAFAGNA DONATO , GRASSI GIUSEPPE
Published: June 2004

This paper focuses on the dynamics of coupled Chua's circuits driven by two sinusoidal signals. In particular, it is shown that the application of signals with slightly different frequencies enables the new phenomenon of chaotic beats to be generated. Finally, the application of signals with equal frequencies is discussed, with the aim of understanding the formation of beats in nonlinear circuits.
A SIMPLE SMOOTH CHAOTIC SYSTEM WITH A 3-LAYER ATTRACTOR
Authors: ZHOU TIANSHOU , CHEN GUANRONG
Published: June 2004

This Letter reports a simple smooth quadratic autonomous chaotic system with four unstable equilibrium points and three homoclinic orbits, and can display a 3-layer attractor among some others. It is the first example of a simple smooth quadratic system that we know, which can exhibit Šhilnikov chaos without numerical evidence of a route to chaos through period-doubling bifurcations.
MULTIPLE HOPF BIFURCATION AND CHAOTIC REVERSING WAVES IN PROBLEMS WITH O(2) SYMMETRY
Authors: AMDJADI FARIDON
Published: June 2004

Multiple Hopf bifurcation in problems with O(2) symmetry leads to the standing and the traveling wave solutions. Swapping the branches at this point is considered by studying an O(2) symmetric problem on [Formula: see text]. The torus-doubling cascade bifurcations are investigated using canonical coordinate transformation. It is shown that direction reversing chaos can be obtained through a symmetry-increasing bifurcation.
CONTROLLING BIFURCATION AND CHAOS IN INTERNET CONGESTION CONTROL MODEL
Authors: CHEN LIANG , WANG XIAO FAN , HAN ZHENG ZHI
Published: June 2004

The TCP end-to-end congestion control plus RED router queue management can be modeled as a discrete-time dynamical system, which can create complex bifurcating and chaotic behavior. Based on the basic features of the TCP-RED model, we investigate the possibility of controlling bifurcation and chaos in the system via several time-delayed feedback control strategies. Two adaptive parameter-tuning algorithms are proposed and evaluated.
PHASE SYNCHRONIZATION BETWEEN TWO DIFFERENT OSCILLATORS WITH UNIDIRECTIONAL SIGNAL COUPLING
Authors: CHEN J. Y. , WONG K. W. , SHUAI J. W.
Published: June 2004

A control scheme is applied between two different oscillators to study their phase synchronization. It utilizes unidirectional signal coupling and only measures the time interval when the trajectories to the two oscillators' attractors cross the Poincaré surfaces respectively. By using this scheme, phase synchronization (without 2π phase slips) can be obtained between two different chaotic systems whose signal variables have large amplitude mismatch. This unidirectional signal coupling also provides a minimum information flow from the driving system to the response system. Therefore it can be used in synchronizing systems with substantially different dynamics via a channel with low information rate.
ENHANCEMENT OF DETECTABILITY OF NOISY SIGNALS BY STOCHASTIC RESONANCE IN ARRAYS
Authors: LIU ZONGHUA , LAI YING-CHENG , NACHMAN ARJE
Published: June 2004

We propose a scheme to detect signals immersed in strong, externally imposed, undesirable noise (jamming) by making use of the principle of stochastic resonance. The strategy is to construct an array of simple nonlinear oscillators and to apply independent, modulating noise to each oscillator. We show that the collective effect of all oscillators and the interplay between nonlinearity and different noise sources can enhance the detectability of the original signal. For proof of principle we focus on periodic signals mixed with in-band, Gaussian jamming. In particular, we show by both extensive numerical computations and physical arguments that measures of the detectability such as the signal-to-noise ratio can be increased in our scheme. We suggest how the scheme can be implemented in laboratory experiments.
RESTRICTED RANDOM WALK NUMBERS OF THE FIRST AND SECOND KIND
Authors: PADMANABHAN A. S.
Published: June 2004

In a manner analogous to the definition of Stirling numbers of the first and second kind we define a set of numbers for restricted random walks of finite memory. These two sequences of counting numbers should be useful in the exact enumeration of properties of simple and restricted random walks.
THE CARTESIAN MULTIPOLE EXPANSION AS A FOUNDATION FOR FAST MULTIPOLE TYPE ALGORITHMS
Authors: STEIGER DON , AHLBRANDT CALVIN
Published: June 2004

We present a dual origin Cartesian multipole expansion for continuous and discrete charge distributions. The remainder term for the truncated expansion is analyzed and formulas for translating and clustering are derived. The analysis of the remainder term, and the formulas for translating and clustering are equally applicable to one and two center Cartesian expansions.
THE ϕ, ψ SPACE OF BORON ISOSTERES OF AMINO ACIDS: ANAB INITIOSTUDY
Authors: DATAR P. A. , COUTINHO E. C.
Published: June 2004

Boron isosteres [ CH3- CO - BH - CH(R) - CONHCH3; R = CH3, CH2OH , CH2SH ] of natural amino acids have been designed as inhibitors of serine protease based on boron's ability to mimic the transition state of the normal enzyme catalyzed reaction. The conformation and electronic properties of these isosteres have been determined by ab initio calculations at the HF/6-31G** level of theory. The global minimum energy structures of the boron isosteres (which are all identical) and the natural amino acids are radically different. Interestingly, the boron isosteres have favorable conformations with positive values for the ϕ dihedral, which are "disallowed states" for the natural amino acids. This is possible because of the smaller atomic size of boron compared to nitrogen. The molecular electrostatic potential of the boron isosteres is also very different from the natural amino acids. There is a positive potential around the boron atom, which provokes the attack of the Ser195– OH group in the enzyme, resulting in formation of an irreversible enzyme-inhibitor adduct.
CONSTRUCTING THE CRITICAL CURVE FOR A SYMMETRIC TWO-LAYER ISING MODEL
Authors: GHAEMI M. , MIRZA B. , PARSAFAR G. A.
Published: June 2004

A numerical method based on the transfer matrix method is developed to calculate the critical temperature of two-layer Ising ferromagnet with a weak inter-layer coupling. The reduced internal energy per site has been accurately calculated for symmetric ferromagnetic case, with the nearest neighbor coupling K1=K2=K (where K1 and K2 are the nearest neighbor interaction in the first and second layers, respectively) with inter-layer coupling J. The critical temperature as a function of the inter-layer coupling [Formula: see text], is obtained for very weak inter-layer interactions, ξ<0.1. Also a different function is given for the case of the strong inter-layer interactions (ξ>1). The importance of these relations is due to the fact that there is no well tabulated data for the critical points versus J/K. We find the value of the shift exponent ϕ=γ is 1.74 for the system with the same intra-layer interaction and 0.5 for the system with different intra-layer interactions.
A FOURIER TRANSFORM APPROACH FOR TWO-CENTER OVERLAP-LIKE QUANTUM SIMILARITY INTEGRALS OVER SLATER TYPE ORBITALS
Authors: BERLU LILIAN
Published: June 2004

In previous work,1 we presented a one center two range expansion method for the evaluation of the two-center overlap-like quantum similarity integrals over Slater type orbitals which are four orbitals overlap integrals.

In this work, to improve the accuracy and to reduce the calculation times, the above integrals are developed using the Fourier transform approach and the so-called B functions. With the help of angular momentum selection rules, two-center overlap-like quantum similarity integrals are expressed as combinations of usual overlap integrals (e.g. two-orbitals) which could be evaluated very accurately using the Fourier transform method combinated with B functions.
SENSORY SIGNALS IN NEURAL POPULATIONS UNDERLYING TACTILE PERCEPTION AND MANIPULATION
Authors: Goodwin Antony W. , Wheat Heather E.
Published: June 2004

▪ Abstract  For humans to manipulate an object successfully, the motor control system must have accurate information about parameters such as the shape of the stimulus, its position of contact on the skin, and the magnitude and direction of contact force. The same information is required for perception during haptic exploration of an object. Much of these data are relayed by the mechanoreceptive afferents innervating the glabrous skin of the digits. Single afferent responses are modulated by all the relevant stimulus parameters. Thus, only in complete population reconstructions is it clear how each of the parameters can be signaled to the brain independently when many are changing simultaneously, as occurs in most normal movements or haptic exploration. Modeling population responses reveals how resolution is affected by neural noise and intrinsic properties of the population such as the pattern and density of innervation and the covariance of response variability.
ATTENTIONAL MODULATION OF VISUAL PROCESSING
Authors: Reynolds John H. , Chelazzi Leonardo
Published: June 2004

▪ Abstract  Single-unit recording studies in the macaque have carefully documented the modulatory effects of attention on the response properties of visual cortical neurons. Attention produces qualitatively different effects on firing rate, depending on whether a stimulus appears alone or accompanied by distracters. Studies of contrast gain control in anesthetized mammals have found parallel patterns of results when the luminance contrast of a stimulus increases. This finding suggests that attention has co-opted the circuits that mediate contrast gain control and that it operates by increasing the effective contrast of the attended stimulus. Consistent with this idea, microstimulation of the frontal eye fields, one of several areas that control the allocation of spatial attention, induces spatially local increases in sensitivity both at the behavioral level and among neurons in area V4, where endogenously generated attention increases contrast sensitivity. Studies in the slice have begun to explain how modulatory signals might cause such increases in sensitivity.
DESENSITIZATION OF G PROTEIN–COUPLED RECEPTORS AND NEURONAL FUNCTIONS
Authors: Gainetdinov Raul R. , Premont Richard T. , Bohn Laura M. , Lefkowitz Robert J. , Caron Marc G.
Published: June 2004

▪ Abstract  G protein–coupled receptors (GPCRs) have proven to be the most highly favorable class of drug targets in modern pharmacology. Over 90% of nonsensory GPCRs are expressed in the brain, where they play important roles in numerous neuronal functions. GPCRs can be desensitized following activation by agonists by becoming phosphorylated by members of the family of G protein–coupled receptor kinases (GRKs). Phosphorylated receptors are then bound by arrestins, which prevent further stimulation of G proteins and downstream signaling pathways. Discussed in this review are recent progress in understanding basics of GPCR desensitization, novel functional roles, patterns of brain expression, and receptor specificity of GRKs and βarrestins in major brain functions. In particular, screening of genetically modified mice lacking individual GRKs or βarrestins for alterations in behavioral and biochemical responses to cocaine and morphine has revealed a functional specificity in dopamine and μ-opioid receptor regulation of locomotion and analgesia. An important and specific role of GRKs and βarrestins in regulating physiological responsiveness to psychostimulants and morphine suggests potential involvement of these molecules in certain brain disorders, such as addiction, Parkinson's disease, mood disorders, and schizophrenia. Furthermore, the utility of a pharmacological strategy aimed at targeting this GPCR desensitization machinery to regulate brain functions can be envisaged.
CORTICAL NEURAL PROSTHETICS
Authors: Schwartz Andrew B.
Published: June 2004

▪ Abstract  Control of prostheses using cortical signals is based on three elements: chronic microelectrode arrays, extraction algorithms, and prosthetic effectors. Arrays of microelectrodes are permanently implanted in cerebral cortex. These arrays must record populations of single- and multiunit activity indefinitely. Information containing position and velocity correlates of animate movement needs to be extracted continuously in real time from the recorded activity. Prosthetic arms, the current effectors used in this work, need to have the agility and configuration of natural arms. Demonstrations using closed-loop control show that subjects change their neural activity to improve performance with these devices. Adaptive-learning algorithms that capitalize on these improvements show that this technology has the capability of restoring much of the arm movement lost with immobilizing deficits.