bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical Characterization of Differentiated Human Embryonic Stem Cells
Authors: Ofek Gidon , Willard Vincent P. , Koay Eugene J. , Hu Jerry C. , Lin Patrick , Athanasiou Kyriacos A.
Published: May 2009

Human embryonic stem cells (hESCs) possess an immense potential in a variety of regenerative applications. A firm understanding of hESC mechanics, on the single cell level, may provide great insight into the role of biophysical forces in the maintenance of cellular phenotype and elucidate mechanical cues promoting differentiation along various mesenchymal lineages. Moreover, cellular biomechanics can provide an additional tool for characterizing stem cells as they follow certain differentiation lineages, and thus may aid in identifying differentiated hESCs, which are most suitable for tissue engineering. This study examined the viscoelastic properties of single undifferentiated hESCs, chondrogenically differentiated hESC subpopulations, mesenchymal stem cells (MSCs), and articular chondrocytes (ACs). hESC chondrogenesis was induced using either transforming growth factor-β1(TGF-β1) or knock out serum replacer as differentiation agents, and the resulting cell populations were separated based on density. All cell groups were mechanically tested using unconfined creep cytocompression. Analyses of subpopulations from all differentiation regimens resulted in a spectrum of mechanical and morphological properties spanning the range of hESCs to MSCs to ACs. Density separation was further successful in isolating cellular subpopulations with distinct mechanical properties. The instantaneous and relaxed moduli of subpopulations from TGF-β1 differentiation regimen were statistically greater than those of undifferentiated hESCs. In addition, two subpopulations from the TGF-β1 group were identified, which were not statistically different from native articular chondrocytes in their instantaneous and relaxed moduli, as well as their apparent viscosity. Identification of a differentiated hESC subpopulation with similar mechanical properties as native chondrocytes may provide an excellent cell source for tissue engineering applications. These cells will need to withstand any mechanical stimulation regimen employed to augment the mechanical and biochemical characteristics of the neotissue. Density separation was effective at purifying distinct populations of cells. A differentiated hESC subpopulation was identified with both similar mechanical and morphological characteristics as ACs. Future research may utilize this cell source in cartilage regeneration efforts.
Microstructure and Mechanics of Collagen-Fibrin Matrices Polymerized Using Ancrod Snake Venom Enzyme
Authors: Rowe Shaneen L. , Stegemann Jan P.
Published: May 2009

The relationship between microstructural features and macroscopic mechanical properties of engineered tissues was investigated in pure and mixed composite scaffolds consisting of collagen Type I and fibrin proteins containing embedded smooth muscle cells. In order to vary the matrix microstructure, fibrin polymerization in mixed constructs was initiated using either the blood-derived enzyme thrombin or the snake venom-derived enzyme ancrod, each at low and high concentrations. Microstructural features of the matrix were quantified by analysis of high resolution scanning electron micrographs. Mechanical properties of the scaffolds were assessed by uniaxial tensile testing as well as creep testing. Viscoelastic parameters were determined by fitting creep data to Burger’s four-parameter model. Oscillatory dynamic mechanical testing was used to determine the storage modulus, loss modulus, and phase shift of each matrix type. Mixed composite scaffolds exhibited improved tensile stiffness and strength, relative to pure collagen matrices, as well as decreased deformation and slower relaxation in creep tests. Storage and loss moduli were increased in mixed composites compared with pure collagen, while phase shift was reduced. A correlation analysis showed that the number of fiber bundles per unit volume was positively correlated with matrix modulus, strength, and dynamic moduli, though this parameter was negatively correlated with phase shift. Fiber diameter also was negatively correlated with scaffold strength. This study demonstrates how microstructural features can be related to the mechanical function of protein matrices and provides insight into structure-function relationships in such materials. This information can be used to identify and promote desirable microstructural features when designing biomaterials and engineered tissues.
Linear and Angular Head Acceleration Measurements in Collegiate Football
Authors: Rowson Steven , Brolinson Gunnar , Goforth Mike , Dietter Dave , Duma Stefan
Published: May 2009

Each year, between 1.6×106 and 3.8×106 concussions are sustained by athletes playing sports, with football having the highest incidence. The high number of concussions in football provides a unique opportunity to collect biomechanical data to characterize mild traumatic brain injury. Human head acceleration data for a range of impact severities were collected by instrumenting the helmets of collegiate football players with accelerometers. The helmets of ten Virginia Tech football players were instrumented with measurement devices for every game and practice for the 2007 football season. The measurement devices recorded linear and angular accelerations about each of the three axes of the head. Data for each impact were downloaded wirelessly to a sideline data collection system shortly after each impact occurred. Data were collected for 1712 impacts, creating a large and unbiased data set. While a majority of the impacts were of relatively low severity (<30 g and <2000 rad/s2), 172 impacts were greater than 40 g and 143 impacts were greater than 3000 rad/s2. No instrumented player sustained a clinically diagnosed concussion during the 2007 season. A large and unbiased data set was compiled by instrumenting the helmets of collegiate football players. Football provides a unique opportunity to collect head acceleration data of varying severity from human volunteers. The addition of concurrent concussive data may advance the understanding of the mechanics of mild traumatic brain injury. With an increased understanding of the biomechanics of head impacts in collegiate football and human tolerance to head acceleration, better equipment can be designed to prevent head injuries.
Effect of MexXY Overexpression on Ceftobiprole Susceptibility in
Pseudomonas aeruginosa
Authors: Baum Ellen Z. , Crespo-Carbone Steven M. , Morrow Brian J. , Davies Todd A. , Foleno Barbara D. , He Wenping , Queenan Anne Marie , Bush Karen
Published: May 2009

Ceftobiprole, an anti-methicillin-resistant
Staphylococcus aureus
broad-spectrum cephalosporin, has activity (MIC for 50% of strains tested, ≤4 μg/ml) against many
Pseudomonas aeruginosa
strains. A common mechanism of
P
.
aeruginosa
resistance to β-lactams, including cefepime and ceftazidime, is efflux via increased expression of Mex pumps, especially MexAB. MexXY has differential substrate specificity, recognizing cefepime but not ceftazidime. In ceftobiprole clinical studies, paired isolates of
P
.
aeruginosa
from four subjects demonstrated ceftobiprole MICs of 2 to 4 μg/ml at baseline but 16 μg/ml posttreatment, unrelated to β-lactamase levels. Within each pair, the level of
mexXY
RNA, but not
mexAB
,
mexCD
, and
mexEF
, increased by an average of 50-fold from baseline to posttreatment isolates. Sequencing of the negative regulatory gene
mexZ
indicated that each posttreatment isolate contained a mutation not present at baseline.
mexXY
expression as a primary ceftobiprole and cefepime resistance mechanism was further examined in isogenic pairs by using cloned
mexXY
and
mexZ
. Expression of cloned
mexXY
in strain PAO1 or in a baseline isolate increased the ceftobiprole MIC to that for the posttreatment isolate. In contrast, in posttreatment isolates, lowering
mexXY
expression via introduction of cloned
mexZ
decreased the ceftobiprole MIC to that for the baseline isolates. Similar changes were observed for cefepime. A spontaneous mutant selectively overexpressing
mexXY
displayed a fourfold elevation in its ceftobiprole MIC, while overexpression of
mexAB
, -
CD
, and -
EF
had a minimal effect. These data indicate that ceftobiprole, like cefepime, is an atypical β-lactam that is a substrate for the MexXY efflux pump in
P
.
aeruginosa
.
Data Mining Validation of Fluconazole Breakpoints Established by the European Committee on Antimicrobial Susceptibility Testing
Authors: Cuesta Isabel , Bielza Concha , Larrañaga Pedro , Cuenca-Estrella Manuel , Laguna Fernando , Rodriguez-Pardo Dolors , Almirante Benito , Pahissa Albert , Rodríguez-Tudela Juan L.
Published: May 2009

European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints classify
Candida
strains with a fluconazole MIC ≤ 2 mg/liter as susceptible, those with a fluconazole MIC of 4 mg/liter as representing intermediate susceptibility, and those with a fluconazole MIC > 4 mg/liter as resistant. Machine learning models are supported by complex statistical analyses assessing whether the results have statistical relevance. The aim of this work was to use supervised classification algorithms to analyze the clinical data used to produce EUCAST fluconazole breakpoints. Five supervised classifiers (J48, Correlation and Regression Trees [CART], OneR, Naïve Bayes, and Simple Logistic) were used to analyze two cohorts of patients with oropharyngeal candidosis and candidemia. The target variable was the outcome of the infections, and the predictor variables consisted of values for the MIC or the proportion between the dose administered and the MIC of the isolate (dose/MIC). Statistical power was assessed by determining values for sensitivity and specificity, the false-positive rate, the area under the receiver operating characteristic (ROC) curve, and the Matthews correlation coefficient (MCC). CART obtained the best statistical power for a MIC > 4 mg/liter for detecting failures (sensitivity, 87%; false-positive rate, 8%; area under the ROC curve, 0.89; MCC index, 0.80). For dose/MIC determinations, the target was >75, with a sensitivity of 91%, a false-positive rate of 10%, an area under the ROC curve of 0.90, and an MCC index of 0.80. Other classifiers gave similar breakpoints with lower statistical power. EUCAST fluconazole breakpoints have been validated by means of machine learning methods. These computer tools must be incorporated in the process for developing breakpoints to avoid researcher bias, thus enhancing the statistical power of the model.
Ultrasensitive Genotypic Detection of Antiviral Resistance in Hepatitis B Virus Clinical Isolates
Authors: Fang Jie , Wichroski Michael J. , Levine Steven M. , Baldick Carl J. , Mazzucco Charles E. , Walsh Ann W. , Kienzle Bernadette K. , Rose Ronald E. , Pokornowski Kevin A. , Colonno Richard J. , Tenney Daniel J.
Published: May 2009

Amino acid substitutions that confer reduced susceptibility to antivirals arise spontaneously through error-prone viral polymerases and are selected as a result of antiviral therapy. Resistance substitutions first emerge in a fraction of the circulating virus population, below the limit of detection by nucleotide sequencing of either the population or limited sets of cloned isolates. These variants can expand under drug pressure to dominate the circulating virus population. To enhance detection of these viruses in clinical samples, we established a highly sensitive quantitative, real-time allele-specific PCR assay for hepatitis B virus (HBV) DNA. Sensitivity was accomplished using a high-fidelity DNA polymerase and oligonucleotide primers containing locked nucleic acid bases. Quantitative measurement of resistant and wild-type variants was accomplished using sequence-matched standards. Detection methodology that was not reliant on hybridization probes, and assay modifications, minimized the effect of patient-specific sequence polymorphisms. The method was validated using samples from patients chronically infected with HBV through parallel sequencing of large numbers of cloned isolates. Viruses with resistance to lamivudine and other
l
-nucleoside analogs and entecavir, involving 17 different nucleotide substitutions, were reliably detected at levels at or below 0.1% of the total population. The method worked across HBV genotypes. Longitudinal analysis of patient samples showed earlier emergence of resistance on therapy than was seen with sequencing methodologies, including some cases of resistance that existed prior to treatment. In summary, we established and validated an ultrasensitive method for measuring resistant HBV variants in clinical specimens, which enabled earlier, quantitative measurement of resistance to therapy.
Safety and Outcomes of Open-Label Deferasirox Iron Chelation Therapy for Mucormycosis
Authors: Spellberg Brad , Andes David , Perez Mario , Anglim Anne , Bonilla Hector , Mathisen Glenn E. , Walsh Thomas J. , Ibrahim Ashraf S.
Published: May 2009

We sought to describe the safety profile of open-label, adjunctive deferasirox iron chelation therapy in eight patients with biopsy-proven mucormycosis. Deferasirox was administered for an average of 14 days (range, 7 to 21) at 5 to 20 mg/kg of body weight/day. The only adverse effects attributable to deferasirox were rashes in two patients. Deferasirox treatment was not associated with changes in renal or liver function, complete blood count, or transplant immunosuppressive levels. Thus, deferasirox appears safe as an adjunctive therapy for mucormycosis.
Mitochondrial DNA Depletion in Rat Liver Induced by Fosalvudine Tidoxil, a Novel Nucleoside Reverse Transcriptase Inhibitor Prodrug
Authors: Venhoff Ana C. , Lebrecht Dirk , Reuss Frank U. , Heckl-Östreicher Brigitte , Wehr Roland , Walker Ulrich A. , Venhoff Nils
Published: May 2009

Fosalvudine tidoxil is a prodrug derived from the nucleoside reverse transcriptase inhibitor 3-deoxy-3-fluorothymidine (FLT; alovudine). FLT effectively inhibits resistant human immunodeficiency virus type 1, but its clinical development was stopped due to bone marrow and liver toxicity. In this study, we examined the long-term in vivo effects of fosalvudine tidoxil on the mitochondrial DNA (mtDNA) contents in rats. Sprague-Dawley rats received fosalvudine tidoxil (15, 40, or 100 mg/kg of body weight/day) by oral gavage during a period of 8 weeks. Didanosine (100 mg/kg/day) was used as a positive control for mitochondrial toxicity. mtDNA levels in liver, gastrocnemius muscle, sciatic nerve, and inguinal fat pad tissues were quantified by real-time PCR. In hepatic mitochondria, fosalvudine tidoxil induced significant mtDNA depletion. At doses of 15, 40, and 100 mg/kg, the mean hepatic mtDNA values were 62, 64, and 47% of control values, respectively. Rats exposed to 100 mg/kg of fosalvudine tidoxil, unlike all other groups, had slightly elevated levels of glutamate pyruvate transaminase in sera. Didanosine induced a loss of mtDNA (to 48% of the control level) similar to that induced by fosalvudine tidoxil. mtDNA levels in skeletal, neural, and adipose tissues in the negative control and treatment groups were similar. Our results suggest that fosalvudine tidoxil induces mitochondrial hepatotoxicity and that this effect warrants scrutiny in clinical trials.
Pharmacokinetics of Posaconazole Administered Orally or by Nasogastric Tube in Healthy Volunteers
Authors: Dodds Ashley Elizabeth S. , Varkey Jay B. , Krishna Gopal , Vickery Donna , Ma Lei , Yu Xin , Malavade Darshana , Goodwin Megan , Perfect John R. , Power Eddie
Published: May 2009

The use of a nasogastric tube is one means of administering antifungal therapy to critically ill patients unable to receive medication via the oral route. This was a phase 1, open-label, single-center, randomized, crossover study of posaconazole administered via nasogastric tube in healthy volunteers. Each subject received two 400-mg single doses of posaconazole, one administered orally and one administered by nasogastric tube, with a 7-day washout period between each dose. Posaconazole was administered 5 to 10 min after subjects received a nutritional supplement. Blood samples for pharmacokinetic analysis were obtained up to 120 h postdose. The analysis of variance estimate of the study population suggests that the posaconazole nasogastric tube administration least-square mean values of observed maximum concentration (
C
max
), area under the plasma concentration-time curve (AUC) to the last measurable concentration, and AUC to time infinity were 81%, 76%, and 77%, respectively, of the corresponding oral administration values. The reason for lower
C
max
and AUC values when posaconazole is administered via the nasogastric tube route is not known. Oral and nasogastric tube administration of a single 400-mg dose of posaconazole suspension was safe and well tolerated in healthy adult subjects. The incidence and nature of treatment-emergent adverse events were similar with both administration routes, and no serious adverse events or clinically significant laboratory test or vital sign abnormalities were reported. Obtaining plasma posaconazole concentrations may be warranted when posaconazole is given to patients via a nasogastric tube to ensure adequate posaconazole exposure. Strategies that have been shown to enhance posaconazole exposure (such as splitting the dose and minimizing the use of proton pump inhibitors) may also be used.
Novel Anion Liposome-Encapsulated Antisense Oligonucleotide Restores Susceptibility of Methicillin-ResistantStaphylococcus aureusand Rescues Mice from Lethal Sepsis by TargetingmecA
Authors: Meng Jingru , Wang Hui , Hou Zheng , Chen Tao , Fu Jingguo , Ma Xue , He Gonghao , Xue Xiaoyan , Jia Min , Luo Xiaoxing
Published: May 2009

β-Lactam resistance in methicillin (meticillin)-resistantStaphylococcus aureus(MRSA) is caused by the production of an additional low-affinity penicillin-binding protein 2a, which is encoded by themecAgene. The disruption ofmecAmay inhibitmecAexpression and thereafter lead to the restoration of MRSA susceptibility to β-lactams. In this study, we developed a novel anionic liposome for encapsulating and delivering the complexes of a specific anti-mecAphosphorothioate oligodeoxynucleotide (PS-ODN833) and polycation polyethylenimine (PEI). The efficiencies of liposome encapsulation of the complexes were around 79.7% ± 2.7%. The liposomes showed sustained release of PS-ODN833 at 37°C but very low levels of release at 4°C and room temperature. The addition of the encapsulated anti-mecAPS-ODN833-PEI complex to cultures of MRSA strains caused 45, 76, 82, and 93% reductions inmecAexpression, accompanied by the inhibition of MRSA growth on Mueller-Hinton agar containing oxacillin (6 μg/ml) in a concentration-dependent manner. The encapsulated-PS-ODN833 treatment also reduced the MICs of five of the most commonly used antibiotics for MRSA clinical isolates to values within the sensitivity range and rescued mice from MRSA-caused septic death by downregulatingmecA. The survival rates of septic mice increased from 0% for the control group to 53% for the PS-ODN833-treated group. The results were associated with reductions of bacterial titers in the blood of surviving mice. The findings of the present study indicate that an antisense oligodeoxynucleotide targeted tomecAcan significantly restore the susceptibility of MRSA to existing β-lactam antibiotics, providing an apparently novel strategy for treating MRSA infections.
Prospective Open-Label Study of the Administration of Two-Percent Voriconazole Eye Drops
Authors: Al-Badriyeh Daoud , Leung Lok , Roydhouse Trent , Fullinfaw Robert , Daniell Mark , Davies Geoffrey E. , Stewart Kay , Kong David C. M.
Published: May 2009

Thirteen human subjects scheduled for elective anterior segment eye surgery received hourly 2% voriconazole eye drops 4 hours presurgery. No side effects were reported. Significantly, the voriconazole concentration in the aqueous humor of the eye was similar to that reported for the 1% voriconazole solution, suggestive of concentration-independent absorption.
Monoclonal Antibody 11E10, Which Neutralizes Shiga Toxin Type 2 (Stx2), Recognizes Three Regions on the Stx2 A Subunit, Blocks the Enzymatic Action of the Toxin In Vitro, and Alters the Overall Cellular Distribution of the Toxin
Authors: Smith Michael J. , Melton-Celsa Angela R. , Sinclair James F. , Carvalho Humberto M. , Robinson Cory M. , O'Brien Alison D.
Published: May 2009

Monoclonal antibody (MAb) 11E10 recognizes the Shiga toxin type 2 (Stx2) A
1
subunit. The binding of 11E10 to Stx2 neutralizes both the cytotoxic and lethal activities of Stx2, but the MAb does not bind to or neutralize Stx1 despite the 61% identity and 75% similarity in the amino acids of the A
1
fragments. In this study, we sought to identify the segment or segments on Stx2 that constitute the 11E10 epitope and to determine how recognition of that region by 11E10 leads to inactivation of the toxin. Toward those objectives, we generated a set of chimeric Stx1/Stx2 molecules and then evaluated the capacity of 11E10 to recognize those hybrid toxins by Western blot analyses and to neutralize them in Vero cell cytotoxicity assays. We also compared the amino acid sequences and crystal structures of Stx1 and Stx2 for stretches of dissimilarity that might predict a binding epitope on Stx2 for 11E10. Through these assessments, we concluded that the 11E10 epitope is comprised of three noncontiguous regions surrounding the Stx2 active site. To determine how 11E10 neutralizes Stx2, we examined the capacity of 11E10/Stx2 complexes to target ribosomes. We found that the binding of 11E10 to Stx2 prevented the toxin from inhibiting protein synthesis in an in vitro assay but also altered the overall cellular distribution of Stx2 in Vero cells. We propose that the binding of MAb 11E10 to Stx2 neutralizes the effects of the toxin by preventing the toxin from reaching and/or inactivating the ribosomes.
Toll-Like Receptor 9-Dependent Activation of Myeloid Dendritic Cells by Deoxynucleic Acids fromCandida albicans
Authors: Miyazato Akiko , Nakamura Kiwamu , Yamamoto Natsuo , Mora-Montes Héctor M. , Tanaka Misuzu , Abe Yuzuru , Tanno Daiki , Inden Ken , Gang Xiao , Ishii Keiko , Takeda Kiyoshi , Akira Shizuo , Saijo Shinobu , Iwakura Yoichiro , Adachi Yoshiyuki , Ohno Naohito , Mitsutake Kotaro , Gow Neil A. R. , Kaku Mitsuo , Kawakami Kazuyoshi
Published: May 2009

The innate immune system of humans recognizes the human pathogenic fungusCandida albicansvia sugar polymers present in the cell wall, such as mannan and β-glucan. Here, we examined whether nucleic acids fromC. albicansactivate dendritic cells.C. albicansDNA induced interleukin-12p40 (IL-12p40) production and CD40 expression by murine bone marrow-derived myeloid dendritic cells (BM-DCs) in a dose-dependent manner. BM-DCs that lacked Toll-like receptor 4 (TLR4), TLR2, and dectin-1, which are pattern recognition receptors for fungal cell wall components, produced IL-12p40 at levels comparable to the levels produced by BM-DCs from wild-type mice, and DNA from aC. albicans pmr1Δ null mutant, which has a gross defect in mannosylation, retained the ability to activate BM-DCs. This stimulatory effect disappeared completely after DNase treatment. In contrast, RNase treatment increased production of the cytokine. A similar reduction in cytokine production was observed when BM-DCs from TLR9−/−and MyD88−/−mice were used. In a luciferase reporter assay, NF-κB activation was detected in TLR9-expressing HEK293T cells stimulated withC. albicansDNA. Confocal microscopic analysis showed similar localization ofC. albicansDNA and CpG-oligodeoxynucleotide (CpG-ODN) in BM-DCs. Treatment ofC. albicansDNA with methylase did not affect its ability to induce IL-12p40 synthesis, whereas the same treatment completely eliminated the ability of CpG-ODN to induce IL-12p40 synthesis. Finally, impaired clearance of this fungal pathogen was not found in the kidneys of TLR9−/−mice. These results suggested thatC. albicansDNA activated BM-DCs through a TLR9-mediated signaling pathway using a mechanism independent of the unmethylated CpG motif.
Genetic Requirements for
Klebsiella pneumoniae
-Induced Liver Abscess in an Oral Infection Model
Authors: Tu Ya-Chun , Lu Min-Chi , Chiang Ming-Ko , Huang Shu-Ping , Peng Hwei-Ling , Chang Hwan-You , Jan Ming-Shiou , Lai Yi-Chyi
Published: May 2009

Klebsiella pneumoniae
is the predominant pathogen of primary liver abscess. However, our knowledge regarding the molecular basis of how
K. pneumoniae
causes primary infection in the liver is limited. We established an oral infection model that recapitulated the characteristics of liver abscess and conducted a genetic screen to identify the
K. pneumoniae
genes required for the development of liver abscess in mice. Twenty-eight mutants with attenuated growth in liver or spleen samples out of 2,880 signature-tagged mutants that produced the wild-type capsule were identified, and genetic loci which were disrupted in these mutants were identified to encode products with roles in cellular metabolism, adhesion, transportation, gene regulation, and unknown functions. We further evaluated the virulence attenuation of these mutants in independent infection experiments and categorized them accordingly into three classes. In particular, the class I and II mutant strains exhibited significantly reduced virulence in mice, and most of these strains were not detected in extraintestinal tissues at 48 h after oral inoculation. Interestingly, the mutated loci of about one-third of the class I and II mutant strains encode proteins with regulatory functions, and the transcript abundances of many other genes identified in the same screen were markedly changed in these regulatory mutant strains, suggesting a requirement for genetic regulatory networks for translocation of
K. pneumoniae
across the intestinal barrier. Furthermore, our finding that preimmunization with certain class I mutant strains protected mice against challenge with the wild-type strain implied a potential application for these strains in prophylaxis against
K. pneumoniae
infections.
VLSI IMPLEMENTATION OF WiMax CONVOLUTIONAL TURBO CODE ENCODER AND DECODER
Authors: MARTINA MAURIZIO , NICOLA MARIO , MASERA GUIDO
Published: May 2009

A VLSI encoder and decoder implementation for the IEEE 802.16 WiMax convolutional turbo code is presented. Architectural choices employed to achieve high throughput, while granting a limited occupation of resources, are addressed both for the encoder and decoder side, including also the subblock interleaving and symbol selection functions specified in the standard. The complete encoder and decoder architectures, implemented on a 0.13 μm standard cell technology, sustain a decoded throughput of more than 90 Mb/s with a 200 MHz clock frequency. The encoder has the complexity of 9.2 kgate of logic and 187.2 kbit of memory, whereas the complete decoder requires 167.7 kgate and 1163 kbit.
A STEREO VISION-BASED BIN PICKING SYSTEM USING HOPFIELD NEURAL NETWORKS
Authors: RASTGAR HOUMAN , AHMADI MAJID , SID-AHMED MAHER
Published: May 2009

In this paper, a new machine vision algorithm for close-range position sensing and bin picking is presented where a Hopfield Neural Network (HNN) is used for the stereo matching process. Stereo Matching is formulated as an energy minimization task and this minimization is accomplished using the HNNs. Various other important aspects of this Vision System are discussed including camera calibration and objects localization using a clustering algorithm.
OPTIMAL ADAPTIVE PREDICTION FOR MIMO SYSTEMS
Authors: SHAHRRAVA BEHNAM
Published: May 2009

An adaptive predictor for decouplable systems, which is optimal in the minimum mean-square error sense at each sample time is proposed, based on priori knowledge of the structure of the interactor matrix and a canonical form. The adaptive predictor includes the uncertainty associated with the parameter and state estimates. Moreover, it is shown that no optimal solution to indirect adaptive prediction exists for nondecouplable systems having unknown interactor matrix.
ADJOINT NETWORK THEOREM AND FLOATING ELEMENTS IN THE NAM
Authors: SOLIMAN AHMED M.
Published: May 2009

Although the adjoint network theorem preserves all the circuit properties it does not, however, guarantee that the floating property of an element is maintained. In other words, the adjoint of a floating element may not be floating and vice-versa a nonfloating element may have an adjoint floating element as will be explained in this paper.

An important and new property of the Nodal Admittance Matrix (NAM) is that it can identify any element as a floating or nonfloating. The four floating basic building blocks including the nullor are tabulated. It is shown that the nullor and the Voltage Mirror (VM)–Current Mirror (CM) pair are self adjoint. The other two floating elements namely Nullator–CM pair and the VM–Norator pair are adjoint to each other.

The NAM of the Op Amp family and Current Conveyor (CCII) family are also given. Two examples are given demonstrating the generation of two families of CCII filters from two known two-CCII filter circuits with demonstration of the floatation property in each of the two filters.

Although the paper has a tutorial nature it also includes new important results.
CMOS PULSE GENERATOR FOR BPSK, OOK, PAM, AND PPM MODULATIONS
Authors: STORNELLI VINCENZO , FERRI GIUSEPPE , PACE KING
Published: May 2009

This work presents a single chip integrated pulse generator-modulator to be utilized in a short range wireless radio sensors remote control applications. The circuit, which can generate single pulses, modulated in BPSK, OOK, PAM, and also PPM, has been developed in a standard CMOS technology (AMS 0.35 μm). Typical pulse duration is about 1 ns while pulse repetition frequency is until 200 MHz (5 ns "chip" time). The operating supply voltage is ± 2.5 V, while the whole power consumption is about 15 mW. Post-layout parametric and corner analyses have confirmed the theoretical expectations.
ON-CHIP POWER-EFFICIENT CURRENT FLATTENING CIRCUIT
Authors: VAHEDI HALEH , GREGORI STEFANO , MURESAN RADU
Published: May 2009

This paper presents a control circuit which regulates the current consumption of integrated circuits using current injection and voltage scaling techniques. The control circuit can be integrated with smart cards as a countermeasure against power analysis attacks and electromagnetic emanation analysis attacks. We have designed the proposed circuit in 0.18 μm CMOS technology at 1.8 V power supply. The simulation results show that the circuit controls the current through the power supply pin of a model of a smart card microcontroller and attenuates the peak-to-peak current variations by 95%. The power dissipation overhead of the control circuit is less than 20% of the original power dissipation of the smart card microcontroller. Comparing the layout area of the proposed circuit with that of an ASIC 3-DES algorithm in the same technology shows that the control circuit only constitutes 4% of the cryptographic processor. The proposed circuit proves to be especially useful for smart cards and small portable devices, where power dissipation and chip area are critical.
EXACT MINIMIZATION OF AND–EXOR EXPRESSIONS OF PRACTICAL BENCHMARK FUNCTIONS
Authors: HIRAYAMA TAKASHI , NISHITANI YASUAKI
Published: May 2009

We propose faster-computing methods for the minimization algorithm of AND–EXOR expressions, or exclusive-or sum-of-products expressions (ESOPs), and obtain the exact minimum ESOPs of benchmark functions. These methods improve the search procedure for ESOPs, which is the most time-consuming part of the original algorithm. For faster computation, the search space for ESOPs is reduced by checking the upper and lower bounds on the size of ESOPs. Experimental results to demonstrate the effectiveness of these methods are presented. The exact minimum ESOPs of many practical benchmark functions have been revealed by this improved algorithm.
INNOVATION AND SELF-ORGANIZATION IN A MULTI-AGENT MODEL
Authors: ARAÚJO TANYA , MENDES R. VILELA
Published: May 2009

A model is developed to study the effectiveness of innovation and its impact on structure creation on agent-based societies. The abstract model that is developed is easily adapted to any particular field. In an interacting environment, the agents receive something from the environment (the other agents) in exchange for their effort and pay the environment a certain amount of value for the fulfilling of their needs or for the very price of existence in that environment. This is coded by two bit strings and the dynamics of the exchange is based on the matching of these strings to those of the other agents. Innovation is related to the adaptation by the agents of their bit strings to improve some utility function.
STRONG LOWEN'S COMPACTNESS IN L-FUZZY TOPOLOGICAL SPACES
Authors: BAI SHI-ZHONG
Published: May 2009

In this paper, a new compactness in L-fuzzy topological spaces called strong Lowen's compactness is introduced. It is a kind of compactness lying between Lowen's compactness and SR-compactness in L-fuzzy topological spaces. Its topological properties are systematically studied. And some good results are obtained.
A MULTI-OBJECTIVE RISK-BASED FRAMEWORK FOR MISSION CAPABILITY PLANNING
Authors: BUI LAM T. , BARLOW MICHAEL , ABBASS HUSSEIN A.
Published: May 2009

In this paper, we propose a risk-based framework for military capability planning. Within this framework, metaheuristic techniques such as Evolutionary Algorithms are used to deal with multi-objectivity of a class of NP-hard resource investment problems, called The Mission Capability Planning Problem, under the presence of risk factors. This problem inherently has at least two conflicting objectives: minimizing the cost of investment in the resources as well as the makespan of the plans. The framework allows the addition of a risk-based objective to the problem in order to support risk assessment during the planning process. In other words, with this framework, a mechanism of progressive risk assessment is introduced to capability planning.

We analyze the performance of the proposed framework under both scenarios: with and without risk. In the case of no risk, the purpose is to study several optimization-related aspects of the framework such as convergence, trade-off analysis, and its sensitivity to the algorithm parameters; while the second case is to demonstrate the ability of the framework in supporting risk assessment and also robustness analysis.
DETERMINING THE CAUSES OF DEMOCRATIC CONSOLIDATION: A CONSIDERATION OF SEVERAL FUZZY METHODS
Authors: MORDESON JOHN N. , CLARK TERRY D. , KARNIK ADAM , MOORE JACOB , WIERMAN MARK J.
Published: May 2009

We use techniques of group decision making and consensus under fuzzy preferences and fuzzy majority developed so as to compare five methods used for determining the degree of causality of eight variables for democratic consolidation. In particular for Q denoting the linguistic variable 'most', we determine the fuzzy Q-core, i.e. the fuzzy subset of the set of causal variables that are not defeated (are undominated or unpreferred) by the methods. We also calculate the Q-consensus winner, i.e. the fuzzy subset of causal variables yielding the extent to which one variable is preferred to another, where 'preferred' here means stronger cause for democratic consolidation. Finally, we use the techniques of fuzzy outranking relations in preference modeling to generate relational systems of fuzzy preferences by the five methods used to determine the degree of causality of the causal variables.
BEYOND INFORMATION SILOS — AN OMNIPRESENT APPROACH TO SOFTWARE EVOLUTION
Authors: RILLING JUERGEN , WITTE RENÉ , SCHUEGERL PHILIPP , CHARLAND PHILIPPE
Published: May 2009

Nowadays, software development and maintenance are highly distributed processes that involve a multitude of supporting tools and resources. Knowledge relevant for a particular software maintenance task is typically dispersed over a wide range of artifacts in different representational formats and at different abstraction levels, resulting in isolated 'information silos'. An increasing number of task-specific software tools aim to support developers, but this often results in additional challenges, as not every project member can be familiar with every tool and its applicability for a given problem. Furthermore, historical knowledge about successfully performed modifications is lost, since only the result is recorded in versioning systems, but not how a developer arrived at the solution. In this research, we introduce conceptual models for the software domain that go beyond existing program and tool models, by including maintenance processes and their constituents. The models are supported by a pro-active, ambient, knowledge-based environment that integrates users, tasks, tools, and resources, as well as processes and history-specific information. Given this ambient environment, we demonstrate how maintainers can be supported with contextual guidance during typical maintenance tasks through the use of ontology queries and reasoning services.
GUEST EDITORS' INTRODUCTION
Authors: GUREVYCH IRYNA , MÜHLHÄUSER MAX
Published: May 2009

This special issue on Ambient Semantic Computing (ASC) proposes a particular approach to the dawning era of computing where computers leave the desktop and surround us everywhere. ASC is related to the terms Ubiquitous Computing, Pervasive Computing, and Ambient Intelligence — each of these terms is claimed by their protagonists to be a superset of the others, but they all turn out to be synonymous after a close inspection of the actual approaches used and results achieved under either of these headlines. ASC is not intended to become yet another synonymous term; rather, it is an invitation to combine Semantic Computing — the very topic of this journal — with the abovementioned synonymous fields in a particularly fruitful way. In our introduction to this special issue, we will first provide an overview of ASC and then position the enclosed three articles within the ASC landscape.
Basilochelys macrobios
n. gen. and n. sp., a large cryptodiran turtle from the Phu Kradung Formation (latest Jurassic-earliest Cretaceous) of the Khorat Plateau, NE Thailand
Authors: Tong Haiyan , Claude Julien , Naksri Wilailuck , Suteethorn Varavudh , Buffetaut Eric , Khansubha Sasidhorn , Wongko Kamonrak , Yuangdetkla Phisit
Published: May 2009

A large cryptodiran turtle,
Basilochelys macrobios
n. gen. n. sp. is described from the latest Jurassic–earliest Cretaceous Phu Kradung Formation of NE Thailand, on the basis of skull, shell and other postcranial elements.
Basilochelys
presents a combination of primitive and derived characters. The derived characters include sculptured skull roof and shell surface; deeply embedded canalis caroticus internus; foramen posterius canalis carotici interni completely surrounded by pterygoid; neural formula of 6>4<6<6<6<6; anteroposteriorly expanded eleventh and twelfth marginal scutes extending onto the suprapygal and costal plates; narrow vertebral scutes; plastron sutured to the carapace, with large and wide anterior and posterior lobes, long and narrow bridge, very narrow axillary and inguinal notch; wide entoplastron; humeropectoral sulcus located on the posterior part of the entoplastron; anal notch absent. This taxon is placed in Trionychoidae and considered as the most basal member of that group.
Oxygen isotope composition of continental vertebrate apatites from Mesozoic formations of Thailand; environmental and ecological significance
Authors: Amiot Romain , Buffetaut Eric , Lécuyer Christophe , Fernandez Vincent , Fourel François , Martineau François , Suteethorn Varavudh
Published: May 2009

Phosphatic remains (tooth enamel, turtle shell fragments and fish scales) of continental vertebrates (freshwater fish, crocodilians, turtles, and theropod and sauropod dinosaurs) recovered from eight localities of NE Thailand ranging in age from the Late Jurassic to the late Early Cretaceous have been analysed for their oxygen isotopic compositions (δ
18
O
p
). From these preliminary data, local meteoric water δ
18
O
w
values estimated using δ
18
O
p
values of crocodilians and turtles range from −4.1±2‰ at the end of the Jurassic to −8.3±2‰ during the Early Cretaceous, suggesting a transition from dry to wetter climates with increasing amount of seasonal precipitation from several hundred millimetres per year to several thousand millimetres. Measurable offsets in δ
18
O
p
values observed between dinosaur taxa (the spinosaurid theropod
Siamosaurus
, other theropods and nemegtosaurid sauropods) are interpreted in terms of differences in water strategies, and suggest that
Siamosaurus
had habits similar to those of semi-aquatic vertebrates such as crocodilians or freshwater turtles.
The geological and palaeontological exploration of Laos; following in the footsteps of J. B. H. Counillon and A. Pavie
Authors: Steyer J. Sebastien
Published: May 2009

Historical studies on the exploration of SE Asia reveal interesting points concerning the geology and palaeontology of this part of the world: the first geological description of northern Laos was published in 1896 by the French geologist J. B. H. Counillon, a member of the famous Pavie Mission (1879–1895). Although scientific notes are rare in the literature about the Pavie Mission, which dealt with diplomacy and politics, Counillon's studies are very informative: they contain accurate observations on the geomorphology, hydrography, stratigraphy and palaeontology of the Mekong River and its banks. Counillon explored the dangerous region of Luang Prabang (northern Laos) with Captain Cupet. He discovered the first fossil tetrapods from Laos, and, with the help of Vasseur and Repelin, correctly referred them to dicynodont mammal-like reptiles.
Implications of Internet architecture on net neutrality
Authors: Jordan Scott
Published: May 2009

Net neutrality represents the idea that Internet users are entitled to service that does not discriminate on the basis of source, destination, or ownership of Internet traffic. The United States Congress is considering legislation on net neutrality, and debate over the issue has generated intense lobbying. Congressional action will substantially affect the evolution of the Internet and of future Internet research. In this article, we argue that neither the pro nor anti net neutrality positions are consistent with the philosophy of Internet architecture. We develop a net neutrality policy founded on a segmentation of Internet services into infrastructure services and application services, based on the Internet's layered architecture. Our net neutrality policy restricts an Internet service Provider's ability to engage in anticompetitive behavior while simultaneously ensuring that it can use desirable forms of network management. We illustrate the effect of this policy by discussing acceptable and unacceptable uses of network management.
Whither Sockets?
Authors: Neville-Neil George V.
Published: May 2009

One of the most pervasive and longest-lasting interfaces in software is the sockets API. Developed by the Computer Systems Research Group at the University of California at Berkeley, the sockets API was first released as part of the 4.1c BSD operating system in 1982. While there are longer-lived APIs, it is quite impressive for an API to have remained in use and largely unchanged for 27 years. The only major update to the sockets API has been the extension of ancillary routines to accommodate the larger addresses used by IPv6.
The State of Macro
Authors: Blanchard Olivier
Published: May 2009

For a long while after the explosion of macroeconomics in the 1970s, the field looked like a battlefield. Over time, however, mainly because facts do not go away, a largely shared vision both of fluctuations and of methodology has emerged. Not everything is fine. Like all revolutions, this one has come with the destruction of some knowledge, and it suffers from extremism and herding. None of this is deadly, however. The state of macro is good.
The Curse of Natural Resources
Authors: Wick Katharina , Bulte Erwin
Published: May 2009

A large literature has developed that documents a negative association between the presence of natural resources and economic development. In this paper we explore the empirics and theories of the so-called resource curse and try to assess its robustness. We conclude that there are many open questions and that the case of the curse needs revision and nuance.
Oligomeric resistin impairs insulin and AICAR-stimulated glucose uptake in mouse skeletal muscle by inhibiting GLUT4 translocation
Authors: Jørgensen Sebastian Beck , Honeyman Jane , Oakhill Jonathan S. , Fazakerley Daniel , Stöckli Jacqueline , Kemp Bruce E. , Steinberg Gregory R.
Published: May 2009

The hormone resistin is elevated in obesity and impairs glucose homeostasis. Here, we examined the effect of oligomerized human resistin on insulin signaling and glucose metabolism in skeletal muscle and myotubes. This was investigated by incubating mouse extensor digitorum longus (EDL) and soleus muscles and L6 myotubes with physiological concentrations of resistin and assessing insulin-stimulated glucose uptake, cellular signaling, suppressor of cytokine signaling 3 (SOCS-3) mRNA, and GLUT4 translocation. We found that resistin at a concentration of 30 ng/ml decreased insulin-stimulated glucose uptake by 30–40% in soleus muscle and myotubes, whereas in EDL muscle insulin-stimulated glucose uptake was impaired at a resistin concentration of 100 ng/ml. Impaired insulin-stimulated glucose uptake was not associated with reduced Akt phosphorylation or IRS-1 protein or increased SOCS-3 mRNA expression. To further investigate the site(s) at which resistin impairs glucose uptake we treated myotubes and skeletal muscle with the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-4-ribofuranoside (AICAR) and found that, although resistin did not impair AMPK activation, it reduced AICAR-stimulated glucose uptake. These data suggested that resistin impairs glucose uptake at a point common to insulin and AMPK signaling pathways, and we thus measured AS160/TBC1D4 Thr642 phosphorylation and GLUT4 translocation in myotubes. Resistin did not impair TBC1D4 phosphorylation but did reduce both insulin and AICAR-stimulated GLUT4 plasma membrane translocation. We conclude that resistin impairs insulin-stimulated glucose uptake by mechanisms involving reduced plasma membrane GLUT4 translocation but independent of the proximal insulin-signaling cascade, AMPK, and SOCS-3.