bluuebunny/crossref_metadata_2025 huggingface dataset:
On-Line Performance Monitoring With Signal Validation and Uncertainty Estimation
Authors: Auh Geun-Sun
Published: October 2009

Methods are developed for performance monitoring of power plant components. On-line uncertainty estimation algorithms are developed. Since this can give new information about the validity of the measurements, proper use of performance monitoring can be achieved. A sequential fault detection method is introduced for the detection of small faults. This signal validation program gives an additional check for good inputs to the performance monitoring. Low-order models are solved using optimal estimation theory to get analytic measurements. The above algorithms are applied to heat transfer loops with real measurement data.
Fossil Unit Performance—1965–1984
Authors: Voegtle R. B. , Koppe R. H. , McCloskey T. H.
Published: October 2009

This paper presents an overview of the results of a study performed for EPRI covering the historical performance of fossil-fired units 200 MW and larger from 1965 through 1984. The study was based on analysis of the information collected over the years by the Equipment Availability Task Force of the Prime Movers Committee of the Edison Electric Institute (EEI), and more recently by the North American Electric Reliability Council (NERC), and covers approximately 7700 unit-years of operation at 668 individual units.
An Autonomous Artificial Designer of Thermal Energy Systems: Part 1—Theoretical Considerations
Authors: Kott A. S. , May J. H. , Hwang C. C.
Published: October 2009

A knowledge-based approach to automated conceptual design (flowsheet synthesis) of thermal energy systems with strong interactions between heat/power/chemical transformations is presented. The approach is based on a computer-oriented state-space search guided by specially developed heuristics, and makes use of Second Law (exergetic) analysis, rather than mimicking the strategy of a human designer. The original design problem, formulated in terms of an equipment units network, is decomposed and reduced to a level of a network of elementary processes, with a resulting reduction in the search space. A special form of fundamental equations for steady-state open thermodynamic systems, based on a “temperature interval” approach, allows one to determine the effects of work, heat and chemical interactions within the system on the magnitude of Second-Law infeasibility, and on the overall exergy loss over any particular temperature interval, prior to the completion of the design. Based on this treatment, a set of generalized transforming operators, a plausible move generator, and a state evaluation function are formulated. The search algorithm is discussed in detail.
Modeling Alkaline Liquid Metal (Na) Evaporating Thin Films Using Both Retarded Dispersion and Electronic Force Components
Authors: Tipton Joseph B. , Kihm Kenneth D. , Pratt David M.
Published: October 2009

A new thin-film evaporation model is presented that captures the unsimplified dispersion force along with an electronic disjoining pressure component that is unique to liquid metals. The resulting nonlinear fourth-order ordinary differential equation (ODE) is solved using implicit orthogonal collocation along with the Levenberg–Marquardt method. The electronic component of the disjoining pressure should be considered when modeling liquid metal extended meniscus evaporation for a wide range of work function boundary values, which represent physical properties of different liquid metals. For liquid sodium, as an example test material, variation in the work function produces order-of-magnitude differences in the film thickness and evaporation profile.
AMPK Regulates the Circadian Clock by Cryptochrome Phosphorylation and Degradation
Authors: Lamia Katja A. , Sachdeva Uma M. , DiTacchio Luciano , Williams Elliot C. , Alvarez Jacqueline G. , Egan Daniel F. , Vasquez Debbie S. , Juguilon Henry , Panda Satchidananda , Shaw Reuben J. , Thompson Craig B. , Evans Ronald M.
Published: October 2009

Coupling Clocks and Metabolism

Circadian clocks in mammals coordinate behavior and physiology with daily light-dark cycles by driving rhythmic transcription of thousands of genes. The master clock in the brain is set by light, but clocks in peripheral tissues, such as the liver, are set by daily feeding. Such coupling should allow tissues to “anticipate” food consumption and optimize the timing of metabolic processes, but how nutritional status is communicated to peripheral clocks is unclear. Studying cell culture models and mice,

Lamia
et al.

(p.
437
; see the Perspective by

Suter and Schibler

) show that the nutrient-responsive signaling molecule AMPK (AMP-activated protein kinase) provides metabolic information to circadian clocks by triggering phosphorylation and subsequent degradation of the clock component cryptochrome-1. Thus—cryptochromes, which originally evolved as blue-light photoreceptors in plants, act as chemical energy sensors in mammals.
Modalities, Modes, and Models in Functional Neuroimaging
Authors: Friston Karl J.
Published: October 2009

In this, the 21st century, human-brain mapping celebrates 21 years of cognitive activation studies. This review looks at imaging neuroscience and key ideas it has pursued; some ideas portend exciting developments, and others have failed gloriously. In terms of achievements, there is much to celebrate, in the sense that it is difficult to imagine modern neuroscience without brain imaging. I will look at recent advances from the perspectives of functional segregation and integration in the brain, paying special attention to approaches that deal with the distributed and integrated nature of neuronal processing and the questions they address.
Teachers’ Participation in Research Programs Improves Their Students’ Achievement in Science
Authors: Silverstein Samuel C. , Dubner Jay , Miller Jon , Glied Sherry , Loike John D.
Published: October 2009

Teaching Teacher

High-school science teachers rarely have an opportunity to participate in scientific research. A program from Columbia University studies what happens when these teachers do get laboratory experience. After a summer program spanning 2 years, including professional development programs, as well as laboratory research,

Silverstein
et al.

(p.
440
) show that the teachers' students benefit. Students of teachers who participated in this summer research experience showed greater pass rates on the tough New York State Regents exams than did students of teachers who did not participate in the program.
A Ball-and-Chain Polymer Model
Authors: Reichhardt C. J. Olson , Lopatina L. M.
Published: October 2009

A macroscopic toy model provides a method to visualize directly the complex behavior of real polymers.
Fantastic Fixers
Authors: Fulweiler Robinson W.
Published: October 2009

Microbial consortia found at deep-sea cold seeps not only reduce sulfur and oxidize methane, but can also fix nitrogen.
Observing Monopoles in a Magnetic Analog of Ice
Authors: Gingras Michel J. P.
Published: October 2009

Experimental evidence has been found that magnetic poles within metal oxide magnets can be separated.
Evolution and Revolution in Odor Detection
Authors: Benton Richard
Published: October 2009

Similarities and differences between phyla give insights into the evolution of the olfactory system.
Great Expectations
Authors: Miyawaki Atsushi
Published: October 2009

A convergence of diverse disciplines is fueling the expansion of neuroscience research, and underpinning this growth are increasingly advanced technologies such as high-performance computation, simulation and neuron modeling, real-time and high-resolution brain imaging, advanced recording techniques, and detailed neuron mapping. This special issue of
Science
gives a well-deserved nod to the technological innovations that have improved our understanding of the development, function, and disorders of the nervous system, and that will continue to open up many new questions about the human brain.
Norman Ernest Borlaug (1914–2009)
Authors: Dowswell Christopher
Published: October 2009

The innovative efforts of a plant scientist revolutionized farming, changed national agricultural policies, and fed the developing world.
Honors to Researchers Who Probed Atomic Structure of Ribosomes
Authors: Service Robert F.
Published: October 2009

This year's Nobel Prize in chemistry was awarded to three scientists who revealed the atomic structure and inner workings of the ribosome: Ada Yonath of the Weizmann Institute of Science; Thomas Steitz of Yale University; and Venkatraman Ramakrishnan of the Medical Research Council Laboratory of Molecular Biology.
In Holland, the Public Face of Flu Takes a Hit
Authors: Enserink Martin
Published: October 2009

Last week, it was alleged that famed virus hunter Albert Osterhaus has been stoking pandemic fears to promote his own business interests in vaccine development. As
Science
went to press, the Dutch House of Representatives had even slated an emergency debate about the matter.
Russian Expats Challenge Government's ‘Disastrous’ Support for Science
Authors: Allakhverdov Andrey , Pokrovsky Vladimir
Published: October 2009

In response to a 2 October letter signed by 100 Russian researchers working abroad complaining of "the disastrous situation in Russian basic research," Russian officials last week boasted about their support of science, particularly a new program to lure back 100 expat researchers to work at least 2 months a year in a Russian research institute or university.
Lunar Mission: A Slam, But Was It a Dunk?
Authors: Kerr Richard A.
Published: October 2009

NASA officials and scientists have declared the Lunar Crater Observation and Sensing Satellite mission a success despite the absence of the expected spray of dust and debris as the 2-ton hunk of metal slammed into the moon.
From Burning Dung to Global Warming and Back Again
Authors: Kerr Richard A.
Published: October 2009

His childhood in rural India inspired the latest twist in climate scientist Veerabhadran Ramanathan's long career studying—and now fighting—climate change.
Alzheimer's Biomarker Initiative Hits Its Stride
Authors: Miller Greg
Published: October 2009

An effort to develop biomarkers for Alzheimer's disease is churning out new data and making plans to expand.
Longitudinal Alzheimer's Studies Go Global
Authors: Miller Greg
Published: October 2009

In the past few years, several international projects inspired in varying degrees by the Alzheimer's Disease Neuroimaging Initiative (see main text) have gotten off the ground.
Characterization of an Antibody Depletion Assay for Analysis of Bactericidal Antibody Specificity
Authors: Zollinger Wendell D. , Moran Elizabeth E. , Schmiel Deborah H.
Published: October 2009

Serum bactericidal antibodies are important for protection against systemic
Neisseria meningitidis
infections. Consequently, identifying the specific targets of bactericidal antibodies is important for understanding protective immunity to meningococcal disease and for vaccine development and evaluation. We have developed a new assay that can be used to investigate the specificity of serum bactericidal antibodies. Prior to testing for bactericidal activity, antibodies specific for a given antigen or group of antigens are depleted from a serum sample by incubation with the antigen(s) bound to the wells of a 96-well microplate. A dilution series of the antigen is bound to the plate to assess the effectiveness of the antigen in removing the bactericidal antibodies. Removal of antibodies with solid-phase antigen prior to bactericidal testing avoids depletion of complement by soluble immune complexes that can form when soluble antigen is present in the bactericidal test mixture (direct inhibition). The parameters associated with this assay are investigated and compared with those associated with a direct-inhibition assay. The bactericidal depletion assay can be an effective tool for studying the specificity of serum bactericidal antibodies.
Screening Respiratory Samples for Detection of Human Rhinoviruses (HRVs) and Enteroviruses: Comprehensive VP4-VP2 Typing Reveals High Incidence and Genetic Diversity of HRV Species C
Authors: Wisdom A. , Leitch E. C. McWilliam , Gaunt E. , Harvala H. , Simmonds P.
Published: October 2009

Rhinovirus infections are the most common cause of viral illness in humans, and there is increasing evidence of their etiological role in severe acute respiratory tract infections (ARTIs). Human rhinoviruses (HRVs) are classified into two species, species A and B, which contain over 100 serotypes, and a recently discovered genetically heterogeneous third species (HRV species C). To investigate their diversity and population turnover, screening for the detection and the genetic characterization of HRV variants in diagnostic respiratory samples was performed by using nested primers for the efficient amplification of the VP4-VP2 region of HRV (and enterovirus) species and serotype identification. HRV species A, B, and C variants were detected in 14%, 1.8%, and 6.8%, respectively, of 456 diagnostic respiratory samples from 345 subjects (6 samples also contained enteroviruses), predominantly among children under age 10 years. HRV species A and B variants were remarkably heterogeneous, with 22 and 6 different serotypes, respectively, detected among 73 positive samples. Similarly, by using a pairwise distance threshold of 0.1, species C variants occurring worldwide were provisionally assigned to 47 different types, of which 15 were present among samples from Edinburgh, United Kingdom. There was a rapid turnover of variants, with only 5 of 43 serotypes detected during both sampling periods. By using divergence thresholds and phylogenetic analysis, several species A and C variants could provisionally be assigned to new types. An initial investigation of the clinical differences between rhinovirus species found HRV species C to be nearly twice as frequently associated with ARTIs than other rhinovirus species, which matches the frequencies of detection of respiratory syncytial virus. The study demonstrates the extraordinary genetic diversity of HRVs, their rapid population turnover, and their extensive involvement in childhood respiratory disease.
Molecular Epidemiology and Risk Factors for Nasal Carriage of
Staphylococcus aureus
and Methicillin-Resistant
S. aureus
in Infants Attending Day Care Centers in Brazil
Authors: Lamaro-Cardoso Juliana , de Lencastre Hermínia , Kipnis Andre , Pimenta Fabiana C. , Oliveira Luciana S. C. , Oliveira Renato M. , Nouer Simonne S. , Aires-de-Sousa Marta , Milheiriço Catarina , Andrade Ana Lucia Sgambatti
Published: October 2009

Investigations regarding
Staphylococcus aureus
carriage among Brazilian children are scarce. We evaluated the determinants of
S. aureus
and methicillin-resistant
S. aureus
(MRSA) nasal carriage in infants attending day care centers (DCCs) and the molecular features of the MRSA strains. A total of 1,192 children aged 2 months to 5 years attending 62 DCCs were screened for
S. aureus
and MRSA nasal carriage. MRSA isolates were characterized by pulsed-field gel electrophoresis, multilocus sequence typing,
spa
typing, staphylococcal cassette chromosome (SCC)
mec
typing and the presence of the Panton-Valentine leukocidin gene. Logistic regression was performed to determine risk factors associated with
S. aureus
and MRSA colonization.
S. aureus
and MRSA carriage were detected in 371 (31.1%) and 14 (1.2%) children, respectively. Variables found to be independently associated with an increased risk for
S. aureus
carriage included being older than 24 months (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.3 to 2.6) and previous DCC attendance (OR, 1.5; 95% CI, 1.0 to 2.2). Having a mother with a high level of education was a protective factor for nasal colonization (OR, 0.4; 95% CI, 0.2 to 0.8). Moreover, we observed that more children carrying MRSA had younger siblings than children not colonized by MRSA. Among the 14 MRSA strains, three SCC
mec
types (IIIA, IV, and V) were detected, together with a multidrug-resistant dominant MRSA lineage sharing 82.7% genetic similarity with the Brazilian clone (ST239-MRSA-IIIA; ST indicates the sequence type determined by multilocus sequence typing). Although SCC
mec
type V was recovered from one healthy child who had been exposed to known risk factors for hospital-associated MRSA, its genetic background was compatible with community-related MRSA. Our data suggest that DCC attendees could be contributing to MRSA cross-transmission between health care and community settings.
Pseudomonas aeruginosa
Genotype Prevalence in Dutch Cystic Fibrosis Patients and Age Dependency of Colonization by Various
P. aeruginosa
Sequence Types
Authors: van Mansfeld Rosa , Willems Rob , Brimicombe Roland , Heijerman Harry , van Berkhout Ferdinand Teding , Wolfs Tom , van der Ent Cornelis , Bonten Marc
Published: October 2009

The patient-to-patient transmission of highly prevalent
Pseudomonas aeruginosa
clones which are associated with enhanced disease progression has led to strict segregation policies for cystic fibrosis (CF) patients in many countries. However, little is known about the population structure of
P. aeruginosa
among CF patients. The aim of the present cross-sectional study was to determine the prevalence and genetic relatedness of
P. aeruginosa
isolates from CF patients who visited two major CF centers in The Netherlands in 2007 and 2008. These patients represented 45% of the Dutch CF population.
P. aeruginosa
carriage in the respiratory tract was determined by standard microbiological culture techniques, and all phenotypically different isolates in the first specimens recovered in 2007 and 2008 were genotyped by multilocus sequence typing. A total of 313 (57%) of 551 patients whose samples were cultured carried
P. aeruginosa
. Two sequence types (STs), ST406 and ST497, were found in 15% and 5% of the patients, respectively, and 60% of the patients harbored a strain that was also found in at least two other patients. The risk ratios for carrying ST406 and ST497 were 17.8 (95% confidence interval [CI], 7.2 to 43.6) for those aged between 15 and 24 years and 6 (95% CI, 1.4 to 26.1) for those aged >25 years. ST406 and ST497 were not genetically linked to previously described epidemic clones, which were also not found in this CF population. The population structure of
P. aeruginosa
in Dutch CF patients is characterized by the presence of two prevalent STs that are associated with certain age groups and that are not genetically linked to previously described epidemic clones.
Similarity and Divergence among Adherent-Invasive
Escherichia coli
and Extraintestinal Pathogenic
E. coli
Strains
Authors: Martinez-Medina Margarita , Mora Azucena , Blanco Miguel , López Cecilia , Alonso María Pilar , Bonacorsi Stéphane , Nicolas-Chanoine Marie-Hélène , Darfeuille-Michaud Arlette , Garcia-Gil Jesus , Blanco Jorge
Published: October 2009

Adherent-invasive
Escherichia coli
(AIEC) pathovar strains, which are associated with Crohn's disease, share many genetic and phenotypic features with extraintestinal pathogenic
E. coli
(ExPEC) strains, but little is known about the level of genetic similarity between the two pathovars. We aimed to determine the frequency of strains with the “AIEC phenotype” among a collection of ExPEC strains and to further search for a common phylogenetic origin for the intestinal and extraintestinal AIEC strains. The adhesion, invasion, and intramacrophage replication capabilities (AIEC phenotype) of 63 ExPEC strains were determined. Correlations between virulence genotype and AIEC phenotype and between intestinal/extraintestinal origin, serotype, and phylogroup were evaluated for the 63 ExPEC and 23 intestinal AIEC strains. Phylogenetic relationships between extraintestinal and intestinal AIEC strains were determined using multilocus sequence typing (MLST) and pulsed-field gel electrophoresis. Only four (6.35%) ExPEC strains, belonging to the O6:H1, O83:H1, and O25:H4 serotypes, were classified as having an AIEC phenotype. These strains were found to be genetically related to some intestinal AIEC strains of the same serotypes as revealed by MLST. No particular virulence gene sets correlated with the intestinal/extraintestinal origin of the strains or with the AIEC phenotype, whereas the gene sets did correlate with the serogroup. We identified two intestinal AIEC strains and one extraintestinal AIEC strain belonging to the O25:H4 serotype that also belonged to the emerging and virulent clonal group ST131. In conclusion, the ExPEC and AIEC pathovars share similar virulence gene sets, and certain strains are phylogenetically related. However, the majority of ExPEC strains did not behave like AIEC strains, thus confirming that the AIEC pathovar possesses virulence-specific features that, to date, are detectable only phenotypically.
Diagnostic Bioluminescent Phage for Detection of
Yersinia pestis
Authors: Schofield David A. , Molineux Ian J. , Westwater Caroline
Published: October 2009

Yersinia pestis
is the etiological agent of the plague. Because of the disease's inherent communicability, rapid clinical course, and high mortality, it is critical that an outbreak, whether it is natural or deliberate, be detected and diagnosed quickly. The objective of this research was to generate a recombinant
luxAB
(“light”)-tagged reporter phage that can detect
Y. pestis
by rapidly and specifically conferring a bioluminescent signal response to these cells. The bacterial
luxAB
reporter genes were integrated into a noncoding region of the CDC plague-diagnostic phage φA1122 by homologous recombination. The identity and fitness of the recombinant phage were assessed through PCR analysis and lysis assays and functionally verified by the ability to transduce a bioluminescent signal to recipient cells. The reporter phage conferred a bioluminescent phenotype to
Y. pestis
within 12 min of infection at 28°C. The signal response time and signal strength were dependent on the number of cells present. A positive signal was obtained from 10
2
cells within 60 min. A signal response was not detectable with
Escherichia coli
, although a weak signal (100-fold lower than that with
Y. pestis
) was obtained with 1 (of 10)
Yersinia enterocolitica
strains and 2 (of 10)
Yersinia
pseudotuberculosis
strains at the restrictive temperature. Importantly, serum did not prevent the ability of the reporter phage to infect
Y. pestis
, nor did it significantly quench the resulting bioluminescent signal. Collectively, the results indicate that the reporter phage displays promise for the rapid and specific diagnostic detection of cultivated
Y. pestis
isolates or infected clinical specimens.
Interactions and Oligomerization of Hantavirus Glycoproteins
Authors: Hepojoki Jussi , Strandin Tomas , Vaheri Antti , Lankinen Hilkka
Published: October 2009

In this report the basis for the structural architecture of the envelope of hantaviruses, family
Bunyaviridae
, is systematically studied by the interactions of two glycoproteins N and C (Gn and Gc, respectively) and their respective disulfide bridge-mediated homo- and heteromeric oligomerizations. In virion extracts Gn and Gc associated in both homo- and hetero-oligomers which were, at least partially, thiol bridge mediated. Due to strong homo-oligomerization, the hetero-oligomers of Gn and Gc are likely to be mediated by homo-oligomeric subunits. A reversible pH-induced disappearance of a neutralizing epitope in Gc and dissociation of the Gn-Gc complex at pH values below 6.2 provide proteochemical evidence for the fusogenicity of Gc. Incomplete inactivation of virions at acidic pH indicates that additional factors are required for hantavirus fusion, as in the case of pestiviruses of the
Flaviviridae
. Based on similarities to class II fusion proteins, a structure model was created of hantavirus Gc using the Semliki Forest virus E1 protein as a template. In total, 10 binding regions for Gn were found by peptide scanning, of which five represent homotypic (Gn
I
to Gn
V
) and five represent heterotypic (Gc
I
to Gc
V
) interaction sites that we assign as intra- and interspike connections, respectively. In conclusion, the glycoprotein associations were compiled to a model wherein the surface of hantaviruses is formed of homotetrameric Gn complexes interconnected with Gc homodimers. This organization would create the grid-like surface pattern described earlier for hantaviruses in negatively stained electron microscopy specimens.
The Human Papillomavirus Type 18 E2 Protein Is a Cell Cycle-Dependent Target of the SCF
Skp2
Ubiquitin Ligase
Authors: Bellanger Sophie , Tan Chye Ling , Nei Wenlong , He Ping Ping , Thierry Françoise
Published: October 2009

The human papillomavirus type 18 (HPV-18) E2 gene is inactivated in cervical carcinoma after integration of the viral DNA into the host cellular genome. Since E2 represses the transcription of the two viral oncogenes E6 and E7, integration which allows their strong expression is considered a major step in transformation by HPV. We show here that E2 is specifically degraded at the end of the G
1
phase in a Brd4-independent manner, implying that its regulatory functions are cell cycle dependent. Degradation of E2 occurs via the Skp1/Cullin1/F-box Skp2 (SCF
Skp2
) ubiquitin ligase, since silencing of Skp2 induces stabilization of E2. In addition, the amino-terminal domain of E2 can interact with Skp2 as shown by coimmunoprecipitation experiments. We previously showed that E2 inhibits the anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase, leading to accumulation of several of its substrates. We demonstrate here that Skp2, which is a known APC/C substrate in G
1
, is also stabilized by E2. Therefore, by negative feedback, SCF
Skp2
activation could lead to E2 degradation and E6/E7 expression specifically in the late G
1
phase. Moreover, since the SCF
Skp2
can trigger S-phase entry and Skp2 itself is a known oncogene, we believe that E2-mediated accumulation of Skp2, together with E2 degradation leading to putative release of E6 and E7 inhibition, could induce premature S-phase entry in HPV-infected cells, pointing to a direct role of E2 in the early steps of HPV-mediated transformation.
The Range of Human APOBEC3H Sensitivity to Lentiviral Vif Proteins
Authors: Li Melody M. H. , Wu Lily I. , Emerman Michael
Published: October 2009

The
APOBEC3H
gene is polymorphic in humans, with four major population-dependent haplotypes that encode proteins with different levels of antiviral activity. Haplotype II, present most frequently in African populations, encodes the most stable protein and is most active against human immunodeficiency virus type 1 (HIV-1). In contrast to human APOBEC3G, which can be completely counteracted by HIV-1 Vif, the protein encoded by
APOBEC3H
haplotype II is only partially sensitive to Vif, while the protein encoded by
APOBEC3H
haplotype I is completely resistant to HIV-1 Vif. We mapped a residue on APOBEC3H that determines this partial Vif sensitivity. However, it is unclear how HIV-1 can replicate in vivo without the ability to neutralize APOBEC3H antiviral activity. In order to directly address this question, we cloned
vif
genes from HIV-1-infected individuals with different
APOBEC3H
genotypes and tested them for their ability to inhibit human APOBEC3H. We found that while the
APOBEC3H
genotype of infected individuals significantly influences the activity of Vif encoded by their virus, none of the Vif variants tested can completely neutralize APOBEC3H as well as they neutralize APOBEC3G. Consistent with this genetic result, APOBEC3H protein expression in human peripheral blood mononuclear cells was below our limit of detection using newly developed antibodies against the endogenous protein. These results demonstrate that human APOBEC3H is not as strong of a selective force for current HIV-1 infections as human APOBEC3G.
Role of Nuclear Factor Y in Stress-Induced Activation of the Herpes Simplex Virus Type 1 ICP0 Promoter
Authors: Kushnir Anna S. , Davido David J. , Schaffer Priscilla A.
Published: October 2009

Herpesviruses are characterized by the ability to establish lifelong latent infections and to reactivate periodically, leading to recurrent disease. The herpes simplex virus type 1 (HSV-1) genome is maintained in a quiescent state in sensory neurons during latency, which is characterized by the absence of detectable viral protein synthesis. Cellular factors induced by stress may act directly on promoters within the latent viral genome to induce the transcription of viral genes and trigger reactivation. In order to identify which viral promoters are induced by stress and elucidate the cellular mechanism responsible for the induction, we generated a panel of HSV-1 promoter-luciferase constructs and measured their response to heat shock. Of the promoters tested, those of ICP0 and ICP22 were the most strongly upregulated after heat shock. Microarray analysis of lytically infected cells supported the upregulation of ICP0 and ICP22 promoters by heat shock. Mutagenic analysis of the ICP0 promoter identified two regions necessary for efficient heat-induced promoter activity, both containing predicted nuclear factor Y (NF-Y) sites, at bases −708 and −75 upstream of the transcriptional start site. While gel shift analysis confirmed NF-Y binding to both sites, only the site at −708 was important for efficient heat-induced activity. Reverse transcription-PCR analysis of selected viral transcripts in the presence of dominant-negative NF-Y confirmed the requirement for NF-Y in the induction of the ICP0 but not the ICP22 promoter by heat shock in lytically infected cells. These findings suggest that the immediate-early ICP0 gene may be among the first genes to be induced during the early events in HSV-1 reactivation, that NF-Y is important for this induction, and that other factors induce the ICP22 promoter.
Transcriptional Downregulation of
p27KIP1
through Regulation of E2F Function during LMP1-Mediated Transformation
Authors: Everly David N. , Mainou Bernardo A. , Raab-Traub Nancy
Published: October 2009

LMP1 induces the phenotypic transformation of fibroblasts and affects regulators of the cell cycle during this process. LMP1 decreases expression of the cyclin-dependent kinase inhibitor p27 and increases the levels and phosphorylation of cyclin-dependent kinase 2 and the retinoblastoma protein. In the present study, the effects of LMP1 on cell cycle progression and the mechanism of p27 downregulation by LMP1 were determined. Although p27 is frequently regulated at the posttranscriptional level during cell cycle progression and in cancer, LMP1 did not decrease ectopically expressed p27. However, LMP1 did decrease p27 RNA levels and inhibited the activity of p27 promoter reporters. The LMP1-regulated promoter element was mapped to a region containing two E2F sites. Electrophoretic mobility shift assays determined that the regulated
cis
element bound an inhibitory E2F complex containing E2F4 and p130. These findings indicate that LMP1 decreases p27 transcription through effects on E2F family transcription factors. This property likely contributes to the ability of LMP1 to stimulate cell cycle progression.
Replicative Capacity of Human Immunodeficiency Virus Type 1 Transmitted from Mother to Child Is Associated with Pediatric Disease Progression Rate
Authors: Prado Julia G. , Prendergast Andrew , Thobakgale Christina , Molina Claudia , Tudor-Williams Gareth , Ndung'u Thumbi , Walker Bruce D. , Goulder Philip
Published: October 2009

Human immunodeficiency virus (HIV)-infected infants in the developing world typically progress to AIDS or death within the first 2 years of life. However, a minority progress relatively slowly. This study addresses the potential contribution of viral factors to HIV disease progression in eight infants selected from a well-characterized cohort of C clade HIV-infected infants, monitored prospectively from birth in Durban, South Africa. Three infants were defined as “progressors,” and five were defined as “slow progressors.” We observed that slow-progressor infants carry HIV isolates with significantly lower replicative capacity compared to virus from progressors. Furthermore, our data suggest a link between the attenuated viral phenotype and HLA-B* 57/5801 epitope-specific Gag mutational patterns of the transmitted virus and not to coreceptor usage or to the presence of Nef deletions or insertions. These data underline the importance of virus-host interactions and highlight the contribution of viral attenuation through Gag-specific CD8+T-cell escape mutations, among other factors, in the control of pediatric HIV infection.
The Poxvirus A35 Protein Is an Immunoregulator
Authors: Rehm Kristina E. , Jones Gwendolyn J. B. , Tripp Alice A. , Metcalf Mark W. , Roper Rachel L.
Published: October 2009

It was shown previously that the highly conserved vaccinia virus A35 gene is an important virulence factor in respiratory infection of mice. We show here that A35 is also required for full virulence by the intraperitoneal route of infection. A virus mutant in which the A35 gene has been removed replicated normally and elicited improved antibody, gamma interferon-secreting cell, and cytotoxic T-lymphocyte responses compared to wild-type virus, suggesting that A35 increases poxvirus virulence by immunomodulation. The enhanced immune response correlated with an improved control of viral titers in target organs after the development of the specific immune response. Finally, the A35 deletion mutant virus also provided protection from lethal challenge (1,000 50% lethal doses) equal to that of the wild-type virus. Together, these data suggest that A35 deletion viruses will make safer and more efficacious vaccines for poxviruses. In addition, the A35 deletion viruses will serve as improved platform vectors for other infectious diseases and cancer and will be superior vaccine choices for postexposure poxvirus vaccination, as they also provide improved kinetics of the immune response.
Influence of relative compaction on the hydraulic conductivity of completely decomposed granite in Hong Kong
Authors: Yin Jian-Hua
Published: October 2009

The relative compaction (RC) parameter is commonly used for assessment of the degree of compaction of existing fill slopes and (or) for the design and construction of new fill slopes. This technical note presents the results of an experimental study on the relationship of RC with the saturated hydraulic conductivity (ksat) of typical completely decomposed granite (CDG) in Hong Kong. The results are interpreted and discussed. Useful correlations of RC versus ksatand void ratio (e) versus ksatare obtained. It is found that the RC has a significant influence on ksatof CDG. The influence of RC is equivalent to the influence of e on ksatof the soil.
Fundamentals of desiccation cracking of fine-grained soils: experimental characterisation and mechanisms identification
Authors: Peron H. , Hueckel T. , Laloui L. , Hu L. B.
Published: October 2009

This paper presents the results of a comprehensive experimental study of the desiccation of fine-grained soils. Air drying of initially saturated soil slabs in controlled conditions is investigated by performing three kinds of tests: free desiccation tests, constrained desiccation tests (prevented shrinkage), and crack pattern tests. Strains, suction, water content, and crack geometry are investigated. Results reveal that unconstrained drying exhibits two stages: a domain with large, mostly irrecoverable deformations and degree of saturation close to 100%, followed by a domain with lower deformations at a decreasing degree of saturation. Homogeneous soil macroscopic cracking is possible only in the presence of boundary constraints and (or) moisture gradients, inducing the build-up of tensile stresses. Results also show that, for the initially saturated remoulded soils tested here, in the whole sample and near a crack initiation point, the degree of saturation remains very close to 100% until cracking, while cracking onset, the air-entry suction, and the shrinkage limit are close to each other. Cavitation nuclei and the formation of an irregular drying front at cracking initiation are commented upon in light of this observation. Finally, results suggest that the crack pattern geometry is the result of energy redistribution. A quantification of the process is proposed.
On the relationship between matric potential and dielectric properties of organic free soils: a sensitivity study
Authors: Wagner Norman , Scheuermann Alexander
Published: October 2009

High-frequency electromagnetic determination of moisture in porous media, (e.g., soil) is based on the strong relationship between volumetric water content and relative dielectric permittivity. In particular, in fine-grained soils the movement of water is influenced by different surface-bonding forces due to interface processes. The interface effects lead to a number of dielectric relaxation processes (free- and bound-water phase, Maxwell–Wagner effect, counterion relaxation effects). These relaxation processes are the reason for the strong frequency dependence of the electromagnetic material properties below 1 GHz. The matric potential is a measure of the bonding forces on water in the soil. Based on a thermodynamic relationship between soil matric potential and dielectric relaxation behaviour of water in different binding states, a broadband dielectric relaxation model was developed that considers low-frequency dispersion up to 1 MHz as well as losses due to direct-current conductivity. The sensitivity of the model on soil suction was systematically analyzed based on a pedotransfer function (PTF) for soil textures ranging from pure sand up to pure clay. The results are compared with known empirical and semiempirical calibration functions, as well as theoretical mixing models.
Adsorption characteristics of coal in constant-pressure tests
Authors: Sabir Ali , Chalaturnyk R. J.
Published: October 2009

Adsorption characteristics of coal have traditionally been studied using crushed coal specimens. When adsorption tests are run on a crushed coal specimen, adsorption kinematics are not involved and therefore the equilibrium of gases is attained rapidly. In this study, the kinematics of CO2 adsorption have been examined on intact coal and crushed coal specimens using experimental methods where pressure rather than volume of the adsorbing gas was kept constant. To understand the adsorption characteristics of the intact specimen, adsorption isotherms for the crushed coal specimen are required from similar test conditions. The crushed coal adsorption isotherms measured in this study are very similar in shape. However, they indicate a slightly larger capacity than those measured in other studies even for coals of similar rank. The average difference between the total adsorption capacity of crushed coal and the intact coal is about 7 mL of adsorbed CO2 per gram of coal at 4000 kPa. Although the difference in adsorption capacities of intact and crushed coal is small, it is important to understand the impact of adsorption kinematics to reach the final adsorption on the intact coal specimen.
Arctic coastal retreat through block failure
Authors: Hoque Md. Azharul , Pollard Wayne H.
Published: October 2009

This study investigates the mechanics of block failure in frozen bluffs underlain by permafrost along Arctic coasts. Different block failure modes with and without thermoerosional niches and ice wedges are identified. A comprehensive analytical model is developed by coupling slope stability analysis with the progressive formation of a thermoerosional niche and the existence of ice wedges in the perennially frozen backshore area. Model computations involve three steps. First, the stability of frozen cliffs is examined by calculating the factor of safety based on slope analysis using the strength of permafrost soil. Second, in the presence of thermoerosional niches at the base of frozen cliffs, the failure modes and critical niche depths are determined by applying the moving boundary of a developing thermoerosional niche to the stability analysis. Finally, the effects of ice wedges are examined by imposing a change in strength conditions related to the existence of ice wedges at different locations in the potential failure region. Different potential failure modes and the critical combination of features contributing to block failure occurrences in Arctic coastal bluffs are identified through model calculations. Nondimensional parameters, regression equations, and graphs are derived to be used for determining the block failure potential for Arctic coasts.
EFFICIENTLY MINING RECENT FREQUENT PATTERNS OVER ONLINE TRANSACTIONAL DATA STREAMS
Authors: CHEN HUI
Published: October 2009

Recent emerging applications, such as network traffic analysis, web click stream mining, power consumption measurement, sensor network data analysis, and dynamic tracing of stock fluctuation, call for study of a new kind of data, stream data. Many data stream management systems, prototype systems and software components have been developed to manage the streams or extract knowledge from stream data. Mining frequent patterns is a foundational job for the methods of data mining and knowledge discovery. This paper proposes an algorithm for mining the recent frequent patterns over an online data stream. This method uses RFP-tree to store compactly the recent frequent patterns of a stream. The content of each transaction is incrementally updated into the pattern tree upon its arrival by scanning the stream only once. Moreover, the strategy of conservative computation and time decaying model are used to ensure the correctness of the mining results. Finally, the performance results of extensive simulation show that our work can reduce the average processing time of stream data element and it is superior to other analogous algorithms.
AN INTELLIGENT CONTROL ARCHITECTURE FOR ADAPTIVE SERVICE-BASED SOFTWARE SYSTEMS
Authors: JIANG CHANG-HAI , HU HAI , CAI KAI-YUAN , HUANG DAZHI , YAU STEPHEN S.
Published: October 2009

Service-oriented architecture (SOA) for distributed computing has become increasingly popular due to the big advantage that distributed applications can be rapidly synthesized with the needed services provided by various service providers through heterogeneous networks. Systems based on SOA are called Service-based Systems (SBS), and a special variety of SBS, namely the Adaptive Service-Based Systems (ASBS), is aimed to be adaptable to constantly changing user requirements, environments and resource constraints. An important and difficult issue is how to design and develop ASBS to satisfy multiple QoS requirements in an open dynamic environment. In this paper, inspired by the underlying principle of hierarchical intelligent control, a three-layer architecture for developing and deploying ASBS is presented to address this issue. Compared with existing architectures for SBS, the advantage of using our architecture is that it provides the flexibility for system designers to adopt different control based approaches to guarantee user requirements and satisfy resource constraints at different levels of the system. Moreover, our architecture enables the system to take hierarchical adaptation actions at runtime to avoid possible violation of user requirement or resource constraint. An example is given to illustrate how to adopt our architecture to guide the design of a simple ASBS, and preliminary experimental data are presented to demonstrate the feasibility of developing ASBS based on our architecture.
CONTROLLING THE USABILITY OF WEB SERVICES
Authors: KENETT RON S. , HAREL AVI , RUGGERI FABRIZIO
Published: October 2009

Service Oriented Architectures (SOA) enable dynamic integration of Web Services (WS) to accomplish a user's need. As such, they are sensitive to user errors. This article presents a framework for mitigating the risks of user errors due to changes in the service delivery context. The underlying methodology incorporates usability in the design, testing, deployment and operation of dynamic collaborative WS, so that the error-prone elements of the User Interface (UI) are identified and eliminated. The methodology incorporates Statistical Process Control (SPC) of Web Service Indices (WSI), obtained by a Decision Support system for User Interface Design (DSUID), in which the users are elements of the control loop.
GENERATIONAL SUCCESSION: EXAMPLES FROM TUNISIAN FAMILY FIRMS
Authors: FATTOUM SALMA , FAYOLLE ALAIN
Published: October 2009

The family character gathers firms whose weight in the economic activity of countries is considerable for developed countries as well as for the others. However, this type of firm is exposed to not only the threats that challenge all types of firms but they must also face dangers related to their family nature.

Several American and European studies were interested in the succession issues associated with family businesses. However, this topic received very little theoretical and empirical investigation in developing countries. In Tunisia, the push in favor of private firms was given in the 60s. Nearly 50 years later, those entrepreneurs who had received state aid to start their businesses are about to retire. How is this dealt with? How is succession "guaranteed"? Hard as it may be to speculate on the outcome of this succession, can we at least describe its phases first and then consider the factors that could have an impact on it? These central questions to Tunisia's economy have yet to be answered academically.

Our aim, in this paper, is to improve our understanding of the nature of the relation between the founder and his successor during the process of succession in the Tunisian family business while proposing reflections to be carried out to make a success of this generational change.

Our paper is organized as follows. The first part will be an analysis of the literature on family firms and the succession process. In the second part, we will introduce the methodological aspects of our study, which was conducted on six Tunisian family firms at different stages of the succession process. In the third part, we will present and discuss the results.
RADICAL STRATEGIC CHANGE IN ISRAELI HIGH TECHNOLOGY NEW VENTURES
Authors: GIMMON ELI , BENJAMIN EYAL , KATZENSTEIN LIORA
Published: October 2009

This study note explores the major causes that stimulate Radical Strategic Change (RSC) in Israeli high technology new ventures. It explores the factors that make RSC successful in these ventures, based on the Resource-Based-View (RBV).

A multiple case study methodology was applied on four Israeli-based start-up companies that experienced both an un-favorable and a favorable RSC, sequentially.

Our findings suggest that the level of resources was the major impetus for these RSCs, and that the alignment of resources to the environment yielded the desired performance goals for these venture.

Further research is needed to validate the findings of this study.
CORPORATE ENTREPRENEURSHIP: INNOVATION AT THE INTERSECTION BETWEEN CREATIVE DESTRUCTION AND CONTROLLED ADAPTATION
Authors: LASSEN ASTRID HEIDEMANN , NIELSEN SUNA LØWE
Published: October 2009

In spite of a growing body of knowledge on the importance of innovation and change, firms still experience great difficulties in being continuously entrepreneurial. This article addresses reasons for such difficulties. Building on a conceptual discussion, the article first identifies seemingly opposing forces found at the core of corporate entrepreneurship. These forces are in the article described in terms of 'creative destruction' and 'controlled adaptation'. Both forces are identified as being essential to successful corporate entrepreneurship, but set very different agendas, which can be expected to give rise to tension. Next, a case study of a Danish high-tech SME is introduced in order to identify patterns of practices which are potentially supportive of the creation of balance between the seemingly opposing forces. Based on this, the article introduces a framework for discussion of the two forces and the consequences of how they are approached managerially.