bluuebunny/crossref_metadata_2025 huggingface dataset:
Lower incidence of sesquiterpene lactone sensitivity in a population in Asia versus a population in Europe: an effect of chrysanthemum tea?
Authors: Mak Rose K. H. , White Ian R. , White Jonathan M. L. , McFadden John P. , Goon Anthony J. T.
Published: August 2007

Sesquiterpene lactones (SLs) (Fig. 1) are an important cause of allergic plant contact dermatitis but are uncommon in the Far East. They belong to the Compositae family of plants. Sensitivity to SL may be airborne or via the topical route [topical herbal remedies, cosmetic products (1), and in many occupations such as gardeners and florists].

The molecular structure of sesquiterpene lactone.

image
Comparison and correlation between stinging responses to lactic acid and bioengineering parameters
Authors: An Susun , Lee Eunyoung , Kim Seunghun , Nam Gaewon , Lee Haekwang , Moon Seongjoon , Chang Ihseop
Published: August 2007

In evaluating the safety of a novel cosmetic product or a new chemical, it is important to assess susceptible population. One group of subjects is known to stingers who are more likely to experience sensory effects such as stinging and burning after contacting with cosmetics. The purpose of the study is to measure skin biophysical parameters noninvasively in stingers and non‐stingers and to see their correlations with stinging responses. 298 women were evaluated by modified lactic acid stinging test with 5% lactic acid solution rather than classic 10% solution because of strong reaction in Asian populations. Transepidermal water loss (TEWL), skin hydration, sebum content, and pH were measured using the bioengineering instruments in an environment‐controlled room. Correlations between stinging responses and skin biophysical parameters were statistically analysed. There was a positive correlation between stinging responses and TEWL evaluation. However, no correlations was observed between stinging responses and other parameters such as skin hydration, sebum content, and pH. Our data indicate that there is a relationship between the degree of stinging and the skin barrier function. However, we believe that various additional studies are necessary to characterize skin of stingers and the pathogenesis.
Prevalence and 1‐year outcome of facial allergic contact dermatitis in patients patch tested in a university hospital
Authors: Li Lin‐Feng , Liu Guangren , Wang Jing
Published: August 2007

Little is known about the prognosis of facial allergic contact dermatitis (FACD). The objective of the study was to investigate the prevalence and 1‐year outcome of FACD in patients patch tested. 655 consecutive patients patch tested with European standard series in Peking University Hospital in a 2‐year period were studied. At 1 year after testing, all patients were asked a revisit and prognosis of FACD was assessed by the rates of clearance of dermatitis, relapse, and improvement at the final evaluation. Of 599 patients examined, 92 were affected by FACD. All their dermatitis improved. The clearance rate was 55.4%, which was much higher than that (23.1%) of other patients tested in the same period (P < 0.05, chi‐square test); however, the relapse rate was also high (42.4%). Concurrence of atopic diathesis, icthyosis, or drug allergy history had no influence on the clearance rates. The clearance rate was significantly lower (40.9%) in patients with disease duration over 3 months before testing. FACD is common among patients patch tested and has a better prognosis than other eczema. Patients with suspected FACD should be tested early and more work is needed to decrease the relapse rate.
The bone‐regenerative properties of Emdogain adsorbed onto poly(d,l‐lactic‐coglycolic acid)/calcium phosphate composites in an ectopic and an orthotopic rat model
Authors: Plachokova A. S. , Van Den Dolder J. , Jansen J. A.
Published: August 2007

Background and Objective:  The aim of this study was to evaluate the bone‐regenerative properties of Emdogain® in osseous and nonosseous sites.

Material and Methods:  For the orthotopic study, unloaded poly(d,l‐lactic‐coglycolic acid)/calcium phosphate implants, and poly(d,l‐lactic‐coglycolic acid)/calcium phosphate implants loaded with different concentrations (0.25, 0.50 or 0.80 mg per implant) of enamel matrix derivative (EMD), were inserted into cranial defects of 24 rats. The implantation time was 4 wk. For the ectopic study, 32 implants were placed subcutaneously. The same study period and groups as in the orthotopic study were used. Methods of evaluation consisted of descriptive histology, histomorphometry and an in vitro EMD‐release study.

Results:  In the orthotopic study, new bone formation was most abundant in unloaded implants followed by 0.50‐mg EMD composites. Histomorphometric measurements showed 54 ± 15.0% bone ingrowth for unloaded implants, 19 ± 22.5% bone ingrowth for 0.25‐mg EMD composites, 40 ± 23.6% bone ingrowth for 0.50‐mg EMD composites and 26 ± 17.6% bone ingrowth for 0.80‐mg EMD composites. Light microscopic analysis of the subcutaneous sections from the ectopic study revealed no bone formation in any group after 4 wk. The in vitro release study showed 60% cumulative EMD release after 4 wk.

Conclusion:  Emdogain® is not osteoinductive and is not able to enhance bone healing in combination with an osteoconductive material, such as poly(d,l‐lactic‐coglycolic acid)/calcium phosphate cement.
Melatonin inhibits free radical‐mediated mitochondrial‐dependent hepatocyte apoptosis and liver damage induced during malarial infection
Authors: Guha Mithu , Maity Pallab , Choubey Vinay , Mitra Kalyan , Reiter Russel J. , Bandyopadhyay Uday
Published: August 2007

Abstract:  We showed earlier that malarial infection significantly induces liver apoptosis mediated by oxidative stress mechanisms. Thus, a nontoxic antioxidant–antiapoptotic molecule may be beneficial for hepatoprotection. Melatonin remarkably prevents hepatocyte apoptosis in mice induced during malaria as indicated by caspase 3 and TUNEL assays as well as transmission electron microscopy (TEM) of the liver tissue. The mitochondrial apoptotic pathway, which plays a critical role in liver cell death during malarial infection, was almost completely suppressed by melatonin as it corrects both the overexpression of Bax and down‐regulation of bcl‐2 as revealed by semiquantitative RT‐PCR. Fluorometric studies using JC‐1 documented that melatonin also restores mitochondrial transmembrane potential (ΔΨm) in malaria‐infected mice liver. The antiapoptotic effect of melatonin is associated with its antioxidant role because melatonin protects liver from oxidative stress induced during malaria by scavenging the hydroxyl radicals, preventing the depletion of reduced glutathione, inhibiting lipid peroxidation and protein carbonyl formation. The effective antioxidant dose of melatonin to protect liver from oxidative stress during malaria is 20 times lower than that of known antioxidants, vitamin C and vitamin E. Apoptosis of hepatocytes during malarial infection is well correlated with dysfunction of the liver while melatonin offers hepatoprotective effects as indicated by different liver function tests. Thus, melatonin may well be effective in combating oxidative stress‐induced apoptosis and liver damage during malaria infection.
EXCHANGE MARKET PRESSURE, MONETARY POLICY, AND ECONOMIC GROWTH: ARGENTINA, 1993–2004
Authors: GARCÍA Clara , MALET Nuria
Published: August 2007

The exchange market pressure (EMP) against a currency has been frequently measured as the sum of the loss of international reserves plus the loss of nominal value of that currency. This paper follows the tradition of investigating the interactions between such a measure of EMP and monetary policy; but it also questions the usual omission of output growth in empirical investigations. The focus of this work is Argentina between 1993 and 2004. As in previous studies, we found some evidence of a positive and double‐direction relationship between EMP and domestic credit. But output growth also played a role in the determination of EMP, even more than domestic credit or interest rates. Also, there is some evidence that EMP affected growth negatively.
Building Bridges Between School‐Based Health Clinics and Schools
Authors: Richardson Jeanita W.
Published: August 2007

Background:  The 2 institutions that hold great promise in mitigating the negative cyclical relationship between poor health and educational readiness are schools and school‐based health care facilities (SBHCs). In partnership with schools, SBHCs could have a profound effect on learning outcomes, which include, but are not limited to, poor concentration in school, attendance, and disturbances of normal sequential development. This article provides an overview of the role of federal, state, and local governmental agencies in the development and implementation of public educational policy and funding in an effort to provide SBHCs the foundation for building a bridge between the health and the educational lexicon.

Methods:  This article reviews literature from a wide variety of sources to develop a better understanding of the complexities associated with public K‐12 education and provides suggestions for initiating meaningful interactions between SBHC supporters and educational decision makers.

Results:  Strategic reasoning between supporters of SBHCs and educational policy makers is critical because of the limitations of time and money for those delivering educational services. Additional projects (eg, SBHCs) no matter how well conceived will be difficult to promote unless officials can be convinced that collaboration in school‐based health care actually enhances compliance with the No Child Left Behind Act.

Conclusions:  Though SBHCs and schools are both committed to enhancing the lives of children, these institutions speak different languages and are accountable to very different types of public and private bodies.
Use of the Youth Risk Behavior Survey to Monitor Trends for Nutrition and Physical Activity in a Midwest City School District*
Authors: Edwards Jane U. , Magel Rhonda
Published: August 2007

Background:  The Youth Risk Behavior Survey (YRBS) was used by a city school district (∼11,000 students) in the upper Midwest to monitor trends for nutrition and physical activity (PA) behaviors both within and between years and to compare with national 2003 data.

Methods:  Independent random samples were obtained in 1999 (387 middle school [MS] and 931 high school [HS]), in 2001 (322 MS and 367 HS), and in 2003 (658 MS and 1026 HS). A two‐sample test of proportions was used.

Results:  Within each survey year, a higher proportion of MS compared to HS reported positive behaviors with some exceptions: (1) an increased proportion of HS having daily physical education (PE) and (2) a reduced proportion of HS reporting media time. Within 2003, a lower proportion of district females compared to males (MS and HS) reported participation in many measured behaviors. District trends overtime indicated a reduced proportion: (1) drinking milk (MS and HS), (2) eating breakfast (HS), and (3) watching television (MS). Trends overtime indicated an increased proportion: (1) using computers for fun (MS and HS), (2) participating in moderate PA (MS), and (3) daily PE (HS). District HS compared to national (2003) indicated a higher proportion: (1) drinking milk, (2) getting moderate PA, and (3) taking daily PE. District HS compared to national indicated a lower proportion: (1) at risk of overweight, (2) overweight, and (3) watching television.

Conclusions:  Analysis of district YRBS trends provides both a database for informed decisions by the school district and an assessment model for other districts.
Forced Unfolding of Proteins Within Cells
Authors: Johnson Colin P. , Tang Hsin-Yao , Carag Christine , Speicher David W. , Discher Dennis E.
Published: August 2007

To identify cytoskeletal proteins that change conformation or assembly within stressed cells, in situ labeling of sterically shielded cysteines with fluorophores was analyzed by fluorescence imaging, quantitative mass spectrometry, and sequential two-dye labeling. Within red blood cells, shotgun labeling showed that shielded cysteines in the two isoforms of the cytoskeletal protein spectrin were increasingly labeled as a function of shear stress and time, indicative of forced unfolding of specific domains. Within mesenchymal stem cells—as a prototypical adherent cell—nonmuscle myosin IIA and vimentin are just two of the cytoskeletal proteins identified that show differential labeling in tensed versus drug-relaxed cells. Cysteine labeling of proteins within live cells can thus be used to fluorescently map out sites of molecular-scale deformation, and the results also suggest means to colocalize signaling events such as phosphorylation with forced unfolding.
Negative Regulation of Toll-Like Receptor Signaling by NF-κB p50 Ubiquitination Blockade
Authors: Carmody Ruaidhrí J. , Ruan Qingguo , Palmer Scott , Hilliard Brendan , Chen Youhai H.
Published: August 2007

Toll-like receptors (TLRs) trigger the production of inflammatory cytokines and shape adaptive and innate immunity to pathogens. We report the identification of B cell leukemia (Bcl)–3 as an essential negative regulator of TLR signaling. By blocking ubiquitination of p50, a member of the nuclear factor (NF)-κB family, Bcl-3 stabilizes a p50 complex that inhibits gene transcription. As a consequence, Bcl-3–deficient mice and cells were found to be hypersensitive to TLR activation and unable to control responses to lipopolysaccharides. Thus, p50 ubiquitination blockade by Bcl-3 limits the strength of TLR responses and maintains innate immune homeostasis. These findings indicate that the p50 ubiquitination pathway can be selectively targeted to control deleterious inflammatory diseases.
Cervicovaginal Levels of Lactoferrin, Secretory Leukocyte Protease Inhibitor, and RANTES and the Effects of Coexisting Vaginoses in Human Immunodeficiency Virus (HIV)-Seronegative Women with a High Risk of Heterosexual Acquisition of HIV Infection
Authors: Novak Richard M. , Donoval Betty A. , Graham Parrie J. , Boksa Lucy A. , Spear Gregory , Hershow Ronald C. , Chen Hua Yun , Landay Alan
Published: August 2007

Innate immune factors in mucosal secretions may influence human immunodeficiency virus type 1 (HIV-1) transmission. This study examined the levels of three such factors, genital tract lactoferrin [Lf], secretory leukocyte protease inhibitor [SLPI], and RANTES, in women at risk for acquiring HIV infection, as well as cofactors that may be associated with their presence. Women at high risk for HIV infection meeting established criteria (
n
= 62) and low-risk controls (
n
= 33) underwent cervicovaginal lavage (CVL), and the CVL fluid samples were assayed for Lf and SLPI. Subsets of 26 and 10 samples, respectively, were assayed for RANTES. Coexisting sexually transmitted infections and vaginoses were also assessed, and detailed behavioral information was collected. Lf levels were higher in high-risk (mean, 204 ng/ml) versus low-risk (mean, 160 ng/ml,
P
= 0.007) women, but SLPI levels did not differ, and RANTES levels were higher in only the highest-risk subset. Lf was positively associated only with the presence of leukocytes in the CVL fluid (
P
< 0.0001). SLPI levels were lower in women with bacterial vaginosis [BV] than in those without BV (
P
= 0.04). Treatment of BV reduced RANTES levels (
P
= 0.05). The influence, if any, of these three cofactors on HIV transmission in women cannot be determined from this study. The higher Lf concentrations observed in high-risk women were strongly associated with the presence of leukocytes, suggesting a leukocyte source and consistent with greater genital tract inflammation in the high-risk group. Reduced SLPI levels during BV infection are consistent with an increased risk of HIV infection, which has been associated with BV. However, the increased RANTES levels in a higher-risk subset of high-risk women were reduced after BV treatment.
Typical Enteroaggregative and Atypical Enteropathogenic Types of
Escherichia coli
Are the Most Prevalent Diarrhea-Associated Pathotypes among Brazilian Children
Authors: Araujo Joel M. , Tabarelli Graciela F. , Aranda Katia R. S. , Fabbricotti Sandra H. , Fagundes-Neto Ulysses , Mendes Caio M. F. , Scaletsky Isabel C. A.
Published: August 2007

A 1-year prospective study was carried out in two large urban centers of São Paulo State, Brazil, to determine the prevalences and roles of the different
Escherichia coli
pathotypes in children less than 5 years of age with diarrhea presenting to the emergency rooms of public hospitals or visiting private pediatricians' offices. Of the pathotypes sought, typical enteroaggregative and atypical enteropathogenic types of
E. coli
were isolated for 8.9% and 5.4% of 774 diarrhea cases, respectively, and were found to be dominant and significantly associated with diarrhea.
Feasibility of Detecting Human Immunodeficiency Virus Type 1 Drug Resistance in DNA Extracted from Whole Blood or Dried Blood Spots
Authors: Steegen Kim , Luchters Stanley , Demecheleer Els , Dauwe Kenny , Mandaliya Kishor , Jaoko Walter , Plum Jean , Temmerman Marleen , Verhofstede Chris
Published: August 2007

Due to high cost, availability of human immunodeficiency virus type 1 (HIV-1) drug resistance testing in resource-poor settings is still limited. We therefore evaluated the usefulness of viral DNA extracted from either whole blood or dried blood spots (DBS). Samples were collected from 50 patients receiving therapy and 10 therapy-naïve patients. Amplification and sequencing of RNA and DNA was performed using an in-house assay. Protease (PR) and reverse transcriptase (RT) sequences of plasma viral RNA were obtained for 96.6% and 89.7%, respectively, of the 29 patients with a detectable viral load. For cellular viral DNA, useful PR and RT sequences were obtained for 96.6% and 93.1% of the whole-blood-cell samples and for 93.1% and 93.1% of the DBS samples, respectively. For the 31 patients with an undetectable viral load, PR and RT sequences were obtained for 67.7% and 61.3% of the whole-blood-cell DNA preparations and for 54.8% and 58.1% of the DBS DNA preparations, respectively. A good correlation between RNA and DNA sequences was found; most discordances were caused by the detection of mixed amino acids. Of the RT drug-resistant mutations, 13 (38.2%) were seen in RNA only, 6 (17.6%) in DNA only, and 15 (44.1%) in both. Repeated amplification and sequencing of DNA extracts revealed a lack of reproducibility for the detection of drug resistance mutations in a number of samples, indicating a possible founder effect. In conclusion, this study shows the feasibility of genotypic drug resistance testing on whole blood cells or DBS and its possible usefulness for HIV-1 subtyping or examining the overall distribution of drug resistance in a population. For individual patients, RNA sequencing was shown to be superior to DNA sequencing, especially for patients who experienced early treatment failure. The use of DNA extracted from whole blood or DBS for the detection of archived drug resistance mutations deserves further study.
Potential of a Simplified p24 Assay for Early Diagnosis of Infant Human Immunodeficiency Virus Type 1 Infection in Haiti
Authors: George Erik , Beauharnais Carole Anne , Brignoli Emilio , Noel Francine , Bois Gyrlande , De Matteis Rouzier Patricia , Altenor Martine , Lauture Daniel , Hosty Marlène , Mehta Sapna , Wright Peter F. , Pape Jean W.
Published: August 2007

With global efforts to scale up the prevention of mother-to-child transmission services and pediatric antiretroviral therapy, there is an urgent need to introduce a simple, low-cost infant human immunodeficiency virus test in the field. We postulated that the p24 antigen capture enzyme-linked immunosorbent assay could be simplified by eliminating signal amplification without compromising diagnostic accuracy.
The Cytoplasmic Tails of Uukuniemi Virus (
Bunyaviridae
) G
N
and G
C
Glycoproteins Are Important for Intracellular Targeting and the Budding of Virus-Like Particles
Authors: Överby Anna K. , Popov Vsevolod L. , Pettersson Ralf F. , Neve Etienne P. A.
Published: August 2007

Functional motifs within the cytoplasmic tails of the two glycoproteins G
N
and G
C
of Uukuniemi virus (UUK) (
Bunyaviridae
family) were identified with the help of our recently developed virus-like particle (VLP) system for UUK virus (A. K. Overby, V. Popov, E. P. Neve, and R. F. Pettersson, J. Virol.
80
:10428-10435, 2006). We previously reported that information necessary for the packaging of ribonucleoproteins into VLPs is located within the G
N
cytoplasmic tail (A. K. Overby, R. F. Pettersson, and E. P. Neve, J. Virol.
81:
3198-3205, 2007). The G
N
glycoprotein cytoplasmic tail specifically interacts with the ribonucleoproteins and is critical for genome packaging. In addition, two other regions in the G
N
cytoplasmic tail, encompassing residues 21 to 25 and 46 to 50, were shown to be important for particle generation and release. By the introduction of point mutations within these two regions, we demonstrate that leucines at positions 23 and 24 are crucial for the initiation of VLP budding, while leucine 46, glutamate 47, and leucine 50 are important for efficient exit from the endoplasmic reticulum and subsequent transport to the Golgi complex. We found that budding and particle generation are highly dependent on the intracellular localization of both glycoproteins. The short cytoplasmic tail of UUK G
C
contains a lysine at position −3 from the C terminus that is highly conserved among members of the
Phlebovirus
,
Hantavirus
, and
Orthobunyavirus
genera. Mutating this single amino acid residue in G
C
resulted in the mislocalization of not only G
C
but also G
N
to the plasma membrane, and VLP generation was compromised in cells expressing this mutant. Together, these results demonstrate that the cytoplasmic tails of both G
N
and G
C
contain specific information necessary for efficient virus particle generation.
Antiretroviral Drug Therapy Alters the Profile of Human Immunodeficiency Virus Type 1-Specific T-Cell Responses and Shifts the Immunodominant Cytotoxic T-Lymphocyte Response from Gag to Pol
Authors: Karlsson A. C. , Chapman J. M. , Heiken B. D. , Hoh R. , Kallas E. G. , Martin J. N. , Hecht F. M. , Deeks S. G. , Nixon D. F.
Published: August 2007

Antiretroviral drug therapy and cytotoxic T lymphocytes (CTL) both exert selective pressures on human immunodeficiency virus type 1, which influence viral evolution. Compared to chronically infected, antiretroviral-untreated patients, most chronically infected, treated patients with detectable viremia lack a cellular immune response against the Gag 77-85(SL9) epitope but show a new immunodominant response against an epitope in protease PR 76-84. Hence, mutations induced by antiretroviral therapy likely alter the profile of epitopes presented to T cells and thus the direction of the response. The consequences of dual pressures from treatment and CTL need to be considered in monitoring of drug therapy.
Allometric relationships and dendroecology of the dwarf shrubDryas integrifolianear Churchill, subarctic Manitoba
Authors: Au R. , Tardif J.C.
Published: August 2007

Shrubs have generally been overlooked in dendrochronology, and little information exists on allometric relationships in dwarf shrubs. Dryas integrifolia M. Vahl. has been recognized as an important species in revegetation of disturbed gravel pits in northern areas. In this study, the dimensions (mat, stem, and root) of D. integrifolia shrubs were measured in four populations having recolonized disturbed areas, and anatomical slides containing growth rings were prepared for each individual. The first objective was to compare allometric relationships among descriptors of shrub dimension and between these descriptors and shrub age. Secondary objectives included documenting maximum age and evaluation of the potential for cross-dating among shrubs. Strong, consistent allometric relationships between aboveground dimensions were observed among individuals from all sites, although growth rates varied within and between sites. This indicated that even though aboveground shrub dimensions grow proportionally to one another, these measurements cannot be used to infer age, because of differences in growth rates among D. integrifolia shrubs. However, numerous cross-sections from D. integrifolia shrubs could be successfully cross-dated, and a short chronology was developed. The radial growth – climate association was found to be similar to that of dominant tree species of the region regarding the impact of October conditions. Increased snowfall in October prior to and warm May temperature during the year of ring formation appear to restrict growth of these shrubs by altering the onset of the growing season. This study has demonstrated that it is possible to accurately date D. integrifolia shrubs, and this ability may be applied to future studies involving population dynamics and remediation of open gravel sites. Growth rings also have the potential to be used in other Arctic shrubs.
TOPOLOGICAL EFFECT ON PERSISTENT CURRENTS AND THE SIGN OF LOW-FIELD CURRENTS IN n-FOLD TWISTED MOEBIUS STRIPS
Authors: MAITI SANTANU K.
Published: August 2007

I investigate persistent currents and the sign of these currents in a low-field limit (ϕ→0) for n-fold twisted Moebius strips threaded by a slowly varying magnetic flux ϕ and describe the effects of the total number of electrons Ne, chemical potential μ, number of twists n, and disorder on these quantities. Transverse hopping strength (v⊥) of the electrons plays an important role in the periodicity of the persistent current. It is observed that for Moebius strips with an odd number of twists the current shows ϕ0/2 flux-quantum periodicity only when v⊥=0, but if the electrons are allowed to hop along the transverse direction, then current shows ϕ0 flux periodicity for both odd- and even-fold twisted Moebius strips. The sign of the low-field currents also has strong dependence on the number of twists n. For zero transverse hopping strength (v⊥ = 0) the sign of the currents can be predicted exactly in odd-fold twisted Moebius strips that are characterized by fixed Ne only. For impurity free systems, the current shows only diamagnetic sign irrespective of Ne, i.e., whether the systems contain odd or even Ne. In the presence of impurity, the current shows diamagnetic and paramagnetic sign, respectively, for the systems with odd and even Ne. On the other hand, for non-zero transverse hopping strength (v⊥≠0), the sign of the low-field currents cannot be predicted exactly. Then it strongly depends on Ne, μ, and the specific realization of disordered configurations.
SHOT NOISE OF ELECTRON PAIRS IN NONCYCLIC AND NON-ADIABATIC MAGNETIC FIELD
Authors: YE XIAN-JUN
Published: August 2007

By adding a rotating magnetic field in one incoming lead, we calculate the shot noise with different incident states in a 4-lead beam-splitter. The result shows that the shot noise of singlet and triplet states oscillates with the external magnetic field and depends on the symmetric properties of the incident states. Thus, the singlet, entangled triplet, and polarized states can be distinguished by adjusting the magnetic field.
SEISMIC BEHAVIOR OF NON-SEISMICALLY DETAILED REINFORCED CONCRETE STRUCTURAL SYSTEMS AND COMPONENTS — WHAT HAVE WE BEEN LEARNING?
Authors: LI BING , PAN TSO-CHIEN
Published: August 2007

In regions of low to moderate seismic hazard and low wind speed, such as Singapore and Malaysia, buildings with relatively weak lateral load resisting structural system are likely to represent a large portion of the building inventory. Although ground motions, due to long distance earthquakes centered in Sumatra, have occurred in Singapore and Malaysia, there has been no record of earthquake damage locally. Recent post-earthquake investigations indicated that extensive damage has occurred as a result of excessive shear deformation and severe strength degradation of the structural components in non-seismically detailed buildings, thus leading to their full collapse. Therefore, it is of great concern that the strength, ductility, and energy dissipation capacity of these structures are adequate to sustain earthquake-induced loads in regions of low to moderate seismicity. The need for evaluating and improving the detailing of existing structures is obvious. Problems have been encountered when assessing the seismic behavior of non-seismically detailed buildings. They are mainly due to the absence of a theoretical basis for evaluating the element and joint behaviors which are supported by a comprehensive test data. This paper provides an overview of simulated seismic load tests conducted on reinforced concrete beam-column joint subassemblies; columns, and shear walls at the Nanyang Technological University (NTU), Singapore. These investigations attempt to gain a better understanding of the general behaviors of these structural components when subjected to seismic loading.
A Direct Electro-reduction of Silver Compounds: Application to the Preparation of Fine Silver Powder
Authors: Kim Min Seuk , Park Jin-Tai , Kim Sung-Don , Yoon Ho-Sung , Lee Jae-Chun , Sohn Jeong-Soo
Published: August 2007

We developed a new electrochemical method, named a direct electro-reduction of silver compounds, on the purpose of preparing high-purity silver powder from low-grade silver sources. Applying cathodic current converted silver-compound powder into silver powder with almost 100 % current efficiency. Sub-micron silver powder with 99.99+% purity was obtained by the direct electro-reduction of silver chloride powder prepared from the solution containing 0.5 molL- 1 Ag and 1 molL-1 Cu. The chloride content of the electro- reduced powder was about 4 ppm, which was seventy times lower than that of silver powder with unreacted core reduced by hydrazine. Solid-state reaction with a gradual reaction- interface moving through the AgCl particle was suggested based on chronopotentiogram, high magnification SEM observation, and complete conversion of powder core.
Effect of Extension Rate on Stress Corrosion Cracking Velocity Using Electrochemical Noise Analysis
Authors: Lopez Claudia , Gaona Citalli , Borunda Adan , Almeraya Facundo , Martinez Alberto , Carreño Caleb
Published: August 2007

In this work, the experimental results of nucleation, growth, and crack propagation susceptibility in aluminum 2024-T351 are studied. The experimental results were obtained from the constant extension rate test technique using three different extension rates (1X10-6mm/s-1, 2X10-6mm/s-1, and 7x10-6mm/s-1). Electrochemical noise analysis was also used. Scanning electron microscopy (SEM) images showed that the two concentrations of NaCl did not make the aluminum alloy fail under stress. The images did not show pits or other forms of corrosion. The SEM results show that the only failure of the alloy was due to mechanical stress.
Fabrication of Chitosan-Hydroxyapatite Coatings for Biomedical Applications
Authors: Zhitomirsky Igor , Pang Xin
Published: August 2007

An electrophoretic deposition (EPD) method has been developed for the fabrication of nanocomposite hydroxyapatite (HA) - chitosan coatings. Cathodic deposits were obtained on various conductive substrates using suspensions of HA nanoparticles in chitosan solutions. The deposition yield has been studied at various deposition conditions. The method enabled the formation of coatings of different thicknesses in the range of up to 50 μm. The deposit composition and microstructure can be varied by the variation of HA concentration in the suspensions. The method enabled the deposition of HA-chitosan coatings containing Ag particles with antimicrobial properties. It was demonstrated that the composite materials can be deposited as monolayers or coatings of graded compositions. The coatings provided corrosion protection of the 316L stainless steel substrates.
Electrochemical Study and Preparation of Gold Substrates Functionalized with Single-Walled Carbon Nanotubes for DNA Biosensor Application
Authors: Santiago Lenibel , Sanchez-Pomales Germarie , Rios-Pagan Annette , Cabrera Carlos R.
Published: August 2007

We report here the use of self-assembled monolayer (SAM) on gold modified with single-walled carbon nanotubes (SWNTs) as a suitable substrate for deoxyribonucleic acid (DNA) oligonucleotides attachment. For our purpose, the molecule 4- aminothiophenol (4-ATP) was self-assembled on gold by forming a thiolate (Au-S) bond. The amine terminal group of the SAM was used to covalently link SWNTs, which serve as template for the covalent attachment of DNA. Each step were characterized by cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR).
Fabrication and Characterisation of Diamond Ultramicroelectrodes of Diameter < 25 Microns for use in Electroanalysis, Sensing and Imaging Applications
Authors: Holt Katherine B. , Caruana Daren , Foord John , Hu Jingping
Published: August 2007

Boron-doped diamond (BDD) ultramicroelectrodes (UMEs) were fabricated by three methods: (1) CVD deposition of microcrystalline BDD onto sharpened tungsten wires; (2) CVD deposition of nanocrystalline BDD by bias-enhanced growth onto sharpened tungsten wires and (3) selective insulation of BDD 'splinters' formed by breaking a larger BDD electrode. The first two methods produced very sharp, coated wires that could be insulated using a variety of techniques, including nail varnish, electrophoretic paint and epoxy. Good control over exposed electrode size and geometry were achieved and UME electrochemical behavior was observed. The 'splinter' electrodes formed were also of microelectrode dimensions and although there was less control over electrode geometry they were more robust and performed better in the presence of certain redox mediators
Conducting Polymers and Hydrogels for Electrochemically Controlled Drug Release Devices
Authors: Lira Luiz Marcos , Barthus Rosangela , Torresi Susana
Published: August 2007

This work describes the synthesis of two different types of devices for controlled release of drugs. The first system is based on the formation of thin conducting polymer films doped with anions or doped and covered by Nafion® for controlled release of model molecules. These types of devices have shown several limitations, therefore an alternative system based on blends formed by hydrogels and conducting polymers was studied and more promising results were obtained.
Substituent Effects on the Stability of Radical Dianion of 4-R-2-Nitrophenols. Electrochemical and ESR Study.
Authors: Morales Jimmy A. , Frontana Carlos E. , Solano Peralta Alejandro , Bautista Martinez Jose Antonio A. , Cuevas Gonzalez-Bravo Gabriel Eduardo , Gonzalez-Martinez Ignacio , Aguilar-Martinez Martha
Published: August 2007

Voltammetric and spectroelectrochemical-ESR studies of the electro-reduction of five substituted 4-R-2-nitrophenols (R = - H, -OCH3; -CH3; -CN, -CF3) in acetonitrile were made. The results showed that at potential values near the first reduction peak, no ESR signals was recorded for 2-nitrophenol, indicating a difference in stability for the radical anion compared to the behavior reported in DMSO. However, at potential values corresponding to the second peak, the ESR spectrum of this species was detected. Since at this potential, the reduction is related to the transformation of the conjugated base of 2-nitrophenol. The ESR results suggest that the electrogenerated radical dianion protonates partially in solution by acetonitrile. The chemical nature of the radical species obtained during the electro-reduction of 4-R-2- nitrophenols can be modulated through substituent effects and the solvent used in the solution.
Non-transferrin-bound iron reaches mitochondria by a chelator-inaccessible mechanism: biological and clinical implications
Authors: Shvartsman Maya , Kikkeri Raghavendra , Shanzer Abraham , Cabantchik Z. Ioav
Published: August 2007

Non-transferrin-bound iron, commonly found in the plasma of iron-overloaded individuals, permeates into cells via pathways independent of the transferrin receptor. This may lead to excessive cellular accumulation of labile iron followed by oxidative damage and eventually organ failure. Mitochondria are the principal destination of iron in cells and a primary site of prooxidant generation, yet their mode of acquisition of iron is poorly understood. Using fluorescent probes sensitive to iron or to reactive oxygen species, targeted to cytosol and/or to mitochondria, we traced the ingress of labile iron into these compartments by fluorescence microscopy and quantitative fluorimetry. We observed that 1) penetration of non-transferrin-bound iron into the cytosol and subsequently into mitochondria occurs with barely detectable delay and 2) loading of the cytosol with high-affinity iron-binding chelators does not abrogate iron uptake into mitochondria. Therefore, a fraction of non-transferrin-bound iron acquired by cells reaches the mitochondria in a nonlabile form. The physiological role of occluded iron transfer might be to confer cells with a “safe and efficient cytosolic iron corridor” to mitochondria. However, such a mechanism might be deleterious in iron-overload conditions, because it could lead to surplus accumulation of iron in these critical organelles.
Cyclooxygenase-2/prostaglandin E2 accelerates the healing of gastric ulcers via EP4 receptors
Authors: Hatazawa Ryo , Tanaka Akiko , Tanigami Mayu , Amagase Kikuko , Kato Shinichi , Ashida Yasuko , Takeuchi Koji
Published: August 2007

We examined the involvement of cyclooxygenase (COX)-1 as well as COX-2 in the healing of gastric ulcers and investigated which prostaglandin (PG) EP receptor subtype is responsible for the healing-promoting action of PGE2. Male SD rats and C57BL/6 mice, including wild-type, COX-1(−/−), and COX-2(−/−), were used. Gastric ulcers were produced by thermocauterization under ether anesthesia. Gastric ulcer healing was significantly delayed in both rats and mice by indomethacin and rofecoxib but not SC-560 given for 14 days after ulceration. The impaired healing was also observed in COX-2(−/−) but not COX-1(−/−) mice. Mucosal PGE2 content increased after ulceration, and this response was significantly suppressed by indomethacin and rofecoxib but not SC-560. The delayed healing in mice caused by indomethacin was significantly reversed by the coadministration of 11-deoxy-PGE1 (EP3/EP4 agonist) but not other prostanoids, including the EP1, EP2, and EP3 agonists. By contrast, CJ-42794 (selective EP4 antagonist) significantly delayed the ulcer healing in rats and mice. VEGF expression and angiogenesis were both upregulated in the ulcerated mucosa, and these responses were suppressed by indomethacin, rofocoxib, and CJ-42794. The expression of VEGF in primary rat gastric fibroblasts was increased by PGE2 or AE1-329 (EP4 agonist), and these responses were both attenuated by coadministration of CJ-42794. These results confirmed the importance of COX-2/PGE2 in the healing mechanism of gastric ulcers and further suggested that the healing-promoting action of PGE2 is mediated by the activation of EP4 receptors and is associated with VEGF expression.
NO and cGMP mediate angiotensin AT2receptor-induced renal renin inhibition in young rats
Authors: Siragy Helmy M. , Inagami Tadashi , Carey Robert M.
Published: August 2007

We hypothesized that angiotensin subtype-2 receptor (AT2R) inhibits renal renin biosynthesis in young rats via nitric oxide (NO). We monitored changes in renal NO, cGMP, renal renin content (RRC), and ANG II in 4-wk-old rats in response to low sodium (LNa+) intake alone and combined with 8-h direct renal cortical administration of AT1receptor blocker valsartan (VAL), AT2R blocker PD123319 (PD), NO synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME), NO donor S-nitroso- N-acetyl penicillamine (SNAP), or guanylyl cyclase inhibitor 1H-[1,2,4] oxadiazolo[4,2-α] quinoxaline-1-one (ODQ). In addition, we monitored renal endothelial nitric oxide synthase (eNOS) and neuronal nitric oxide synthase (nNOS) in response to VAL or PD. LNa+, VAL, PD, l-NAME, and ODQ increased RRC, ANG II, and renin mRNA. PD and l-NAME decreased NO and cGMP, while SNAP reduced RRC, ANG II, renin mRNA, and reversed the effects of PD. PD also reduced eNOS and nNOS protein and mRNA. Combined treatment with PD, l-NAME, or ODQ and VAL reversed the effects of VAL and caused further increase in RRC, ANG II, renin mRNA, and protein. ODQ reversed the effects of SNAP. These data demonstrate that the renal AT2receptor decreases renal renin biosynthesis and ANG II production in young rats. Reversal of the PD effects by SNAP and SNAP effects by ODQ confirms that NO and cGMP mediate the AT2receptor inhibition of renal renin production.
Acetazolamide protects against posthypoxic unstable breathing in the C57BL/6J mouse
Authors: Yamauchi Motoo , Dostal Jesse , Strohl Kingman P.
Published: August 2007

Acetazolamide (Acz), a carbonic anhydrase inhibitor, is used to manage periodic breathing associated with altitude and with heart failure. We examined whether Acz would alter posthypoxic ventilatory behavior in the C57BL/6J (B6) mouse model of recurrent central apnea. Experiments were performed with unanesthetized, awake adult male B6 mice ( n = 9), ventilatory behavior was measured using flow-through whole body plethysmography. Mice were given an intraperitoneal injection of either vehicle or Acz (40 mg/kg), and 1 h later they were exposed to 1 min of 8% O2-balance N2 (poikilocapnic hypoxia) or 12% O2-3% CO2-balance N2 (isocapnic hypoxia) followed by rapid reoxygenation (100% O2). Hypercapnic response (8% CO2-balance O2) was examined in six mice. With Acz, ventilation, including respiratory frequency, tidal volume, and minute ventilation, in room air was significantly higher and hyperoxic hypercapnic ventilatory responsiveness was generally lower compared with vehicle. Poikilocapnic and isocapnic hypoxic ventilatory responsiveness were similar among treatments. One minute after reoxygenation, animals given Acz exhibited posthypoxic frequency decline, a lower coefficient of variability for frequency, and no tendency toward periodic breathing, compared with vehicle treatment. We conclude that Acz improves unstable breathing in the B6 model, without altering hypoxic response or producing short-term potentiation, but with some blunting of hypercapnic responsiveness.
Synergistic Antiangiogenic Effects of Stathmin Inhibition and Taxol Exposure
Authors: Mistry Sucharita J. , Bank Alexander , Atweh George F.
Published: August 2007

Stathmin is one of the key regulators of the microtubule cytoskeleton and the mitotic spindle in eukaryotic cells. It is expressed at high levels in a wide variety of human cancers and may provide an attractive target for cancer therapy. We had previously shown that stathmin inhibition results in the abrogation of the malignant phenotype. The microtubule-interfering drug, taxol, has both antitumorigenic and antiangiogenic properties. We had also shown that the antitumor activities of taxol and stathmin inhibition are synergistic. We hypothesized that taxol and stathmin inhibition may also have synergistic antiangiogenic activities. A replication-deficient bicistronic adenoviral vector that coexpresses green fluorescent protein and an anti-stathmin ribozyme was used to target stathmin mRNA. Exposure of endothelial cells to anti-stathmin adenovirus alone resulted in a dose-dependent inhibition of proliferation, migration, and differentiation into capillary-like structures. This inhibition was markedly enhanced by exposure of transduced endothelial cells to very low concentrations of taxol, which resulted in a virtually complete loss of proliferation, migration, and differentiation of endothelial cells. In contrast, exposure of nontransduced endothelial cells to taxol alone resulted in a modest inhibition of proliferation, migration, and differentiation. Our detailed analysis showed that the antiangiogenic effects of the combination of stathmin inhibition and taxol exposure are synergistic. Our studies also showed that the mechanism of this synergistic interaction is likely to be mediated through the stabilization of microtubules. Thus, this novel combination may provide an attractive therapeutic strategy that combines a synergistic antitumor activity with a synergistic antiangiogenic activity. (Mol Cancer Res 2007;5(8):773–82)
A Step Forward
Authors: Feres Júnior João
Published: August 2007

Contributions to the History of Concepts has now completed two years of existence. Its history has been closely tied to the annual meetings of the History of Political and Social Concepts Group (HPSCG). Talks about evolving from the HPSCG’s Newsletter to an academic periodical publication began in Bilbao, in 2003. The following year, at the 7th International Conference on the History of Concepts, which took place in Rio de Janeiro, we designed a plan to create a new journal that would serve as a conduit for researchers working with conceptual history, as well as for scholars interested in other related fields, such as intellectual history, the history of political thought, the history of ideas, etc. After a great deal of ground work, the journal was finally launched in 2005, both in digital and paper format, with an elegant graphic design and a host of excellent texts by distinguished scholars in the fields of conceptual history, intellectual history, and the history of political thought, such as Quentin Skinner, Melvin Richter, Kari Palonen, and Robert Darnton. The response from the international academic community was immediate and very encouraging. Since then positive feedback from a growing audience worldwide has been constantly on the rise.
The Concept of Despotism and l'abus des mots
Authors: Richter Melvin
Published: August 2007

In this article, the author applies the methodology of Begriffsgeschichte to the study of the concept of despotism in France, focusing mainly on the eighteenth century and the Revolution. During this period despotism became a basic concept (Grundbegriff), and thus highly contested. At the same time, the concept's long history, which stretches back to antiquity and includes the semantic boundaries that previously made it indistinguishable from "tyranny," created a diachronic thrust against which anyone seeking to add a new meaning or application had to work. Finally, as other key concepts, despotism produced political consequences unanticipated and undesired by those using it, not only major theorists but also pamphleteers, in a number of intensely fought conflicts which helped bring down the monarchy.
Intellectual History, Liberty and Republicanism
Authors: Sebastián Javier Fernández , Skinner Quentin
Published: August 2007

Quentin Skinner was interviewed by Javier Fernández Sebastián (Universidad del País Vasco, Spain) at the Centro de Estudios Políticos y Constitucionales, Madrid, on March 29, 2006. This interview has appeared in Spanish translation in Historia y Política 16: 237-258 (2006).