bluuebunny/crossref_metadata_2025 huggingface dataset:
Cumulative sum quality control for calibrated breast density measurements
Authors: Heine John J. , Cao Ke , Beam Craig
Published: November 2009

Purpose:

Breast density is a significant breast cancer risk factor. Although various methods are used to estimate breast density, there is no standard measurement for this important factor. The authors are developing a breast density standardization method for use in full field digital mammography (FFDM). The approach calibrates for interpatient acquisition technique differences. The calibration produces a normalized breast density pixel value scale. The method relies on first generating a baseline (BL) calibration dataset, which required extensive phantom imaging. Standardizing prospective mammograms with calibration data generated in the past could introduce unanticipated error in the standardized output if the calibration dataset is no longer valid.

Methods:

Sample points from the BL calibration dataset were imaged approximately biweekly over an extended timeframe. These serial samples were used to evaluate the BL dataset reproducibility and quantify the serial calibration accuracy. The cumulative sum (Cusum) quality control method was used to evaluate the serial sampling.

Results:

There is considerable drift in the serial sample points from the BL calibration dataset that is x‐ray beam dependent. Systematic deviation from the BL dataset caused significant calibration errors. This system drift was not captured with routine system quality control measures. Cusum analysis indicated that the drift is a sign of system wear and eventual x‐ray tube failure.

Conclusions:

The BL calibration dataset must be monitored and periodically updated, when necessary, to account for sustained system variations to maintain the calibration accuracy.
Evaluation of similarity measures for use in the intensity‐based rigid 2D‐3D registration for patient positioning in radiotherapy
Authors: Wu Jian , Kim Minho , Peters Jorg , Chung Heeteak , Samant Sanjiv S.
Published: November 2009

Purpose:

Rigid 2D‐3D registration is an alternative to 3D‐3D registration for cases where largely bony anatomy can be used for patient positioning in external beam radiation therapy. In this article, the authors evaluated seven similarity measures for use in the intensity‐based rigid 2D‐3D registration using a variation in Skerl's similarity measure evaluation protocol.

Methods:

The seven similarity measures are partitioned intensity uniformity, normalized mutual information (NMI), normalized cross correlation (NCC), entropy of the difference image, pattern intensity (PI), gradient correlation (GC), and gradient difference (GD). In contrast to traditional evaluation methods that rely on visual inspection or registration outcomes, the similarity measure evaluation protocol probes the transform parameter space and computes a number of similarity measure properties, which is objective and optimization method independent. The variation in protocol offers an improved property in the quantification of the capture range. The authors used this protocol to investigate the effects of the downsampling ratio, the region of interest, and the method of the digitally reconstructed radiograph (DRR) calculation [i.e., the incremental ray‐tracing method implemented on a central processing unit (CPU) or the 3D texture rendering method implemented on a graphics processing unit (GPU)] on the performance of the similarity measures. The studies were carried out using both the kilovoltage (kV) and the megavoltage (MV) images of an anthropomorphic cranial phantom and the MV images of a head‐and‐neck cancer patient.

Results:

Both the phantom and the patient studies showed the 2D‐3D registration using the GPU‐based DRR calculation yielded better robustness, while providing similar accuracy compared to the CPU‐based calculation. The phantom study using kV imaging suggested that NCC has the best accuracy and robustness, but its slow function value change near the global maximum requires a stricter termination condition for an optimization method. The phantom study using MV imaging indicated that PI, GD, and GC have the best accuracy, while NCC and NMI have the best robustness. The clinical study using MV imaging showed that NCC and NMI have the best robustness.

Conclusions:

The authors evaluated the performance of seven similarity measures for use in 2D‐3D image registration using the variation in Skerl's similarity measure evaluation protocol. The generalized methodology can be used to select the best similarity measures, determine the optimal or near optimal choice of parameter, and choose the appropriate registration strategy for the end user in his specific registration applications in medical imaging.
Design and construction of a quality control phantom for SPECT and PET imaging
Authors: Hunt Dylan Christopher , Easton Harry , Caldwell Curtis B.
Published: November 2009

In this article, the authors present a method for quickly and easily constructing test phantoms for PET and SPECT quality assurance. As a demonstration, they constructed a complex prototype test phantom, showing the strengths of the construction method. Images taken using a PET/CT and a SPECT scanner are presented, along with a qualitative evaluation of PET/CT using the test phantom. The construction technique provides a quick, easy, and cost effective means of constructing a phantom for use in nuclear medicine imaging.
Tissue equivalency of phantom materials for neutron dosimetry in proton therapy
Authors: Dowdell Stephen , Clasie Ben , Wroe Andrew , Guatelli Susanna , Metcalfe Peter , Schulte Reinhard , Rosenfeld Anatoly
Published: November 2009

Purpose:

Previous Monte Carlo and experimental studies involving secondary neutrons in proton therapy have employed a number of phantom materials that are designed to represent human tissue. In this study, the authors determined the suitability of common phantom materials for dosimetry of secondary neutrons, specifically for pediatric and intracranial proton therapy treatments.

Methods:

This was achieved through comparison of the absorbed dose and dose equivalent from neutrons generated within the phantom materials and various ICRP tissues. The phantom materials chosen for comparison were Lucite, liquid water, solid water, and A150 tissue equivalent plastic. These phantom materials were compared to brain, muscle, and adipose tissues.

Results:

The magnitude of the doses observed were smaller than those reported in previous experimental and Monte Carlo studies, which incorporated neutrons generated in the treatment head. The results show that for both neutron absorbed dose and dose equivalent, no single phantom material gives agreement with tissue within 5% at all the points considered. Solid water gave the smallest mean variation with the tissues out of field where neutrons are the primary contributor to the total dose.

Conclusions:

Of the phantom materials considered, solid water shows best agreement with tissues out of field.
Geometric feature‐based multimodal image registration of contrast‐enhanced cardiac CT with gated myocardial perfusion SPECT
Authors: Woo Jonghye , Slomka Piotr J. , Dey Damini , Cheng Victor Y. , Hong Byung‐Woo , Ramesh Amit , Berman Daniel S. , Karlsberg Ronald P. , Kuo C.‐C. Jay , Germano Guido
Published: November 2009

Purpose:

Cardiac computed tomography (CT) and single photon emission computed tomography (SPECT) provide clinically complementary information in the diagnosis of coronary artery disease (CAD). Fused anatomical and physiological data acquired sequentially on separate scanners can be coregistered to accurately diagnose CAD in specific coronary vessels.

Methods:

A fully automated registration method is presented utilizing geometric features from a reliable segmentation of gated myocardial perfusion SPECT (MPS) volumes, where regions of myocardium and blood pools are extracted and used as an anatomical mask to de‐emphasize the inhomogeneities of intensity distribution caused by perfusion defects and physiological variations. A multiresolution approach is employed to represent coarse‐to‐fine details of both volumes. The extracted voxels from each level are aligned using a similarity measure with a piecewise constant image model and minimized using a gradient descent method. The authors then perform limited nonlinear registration of gated MPS to adjust for phase differences by automatic cardiac phase matching between CT and MPS. For phase matching, they incorporate nonlinear registration using thin‐plate‐spline‐based warping. Rigid registration has been compared with manual alignment on 20 stress/rest MPS and coronary CTA data sets acquired from two different sites and five stress CT perfusion data sets. Phase matching was also compared to expert visual assessment.

Results:

As compared with manual alignment obtained from two expert observers, the mean and standard deviation of absolute registration errors of the proposed method for MPS were, , and for translation and , , and for rotation at site A and , , and for translation and , , and for rotation at site B. The results for CT perfusion were , , and for translation and , , and for rotation. The registration error shows that the proposed method achieves registration accuracy of less than 1 voxel misalignment. The proposed method was robust for different initializations in the range from to 70, to 70, and in the ‐, ‐, and ‐axes, respectively. Validation results of finding best matching phase showed that best matching phases were not different by more than two phases, as visually determined.

Conclusions:

The authors have developed a fast and fully automated method for registration of contrast cardiac CT with gated MPS which includes nonlinear cardiac phase matching and is capable of registering these modalities with accuracy in 87% of the cases.
An EPID based method for efficient and precise asymmetric jaw alignment quality assurance
Authors: Clews Luke , Greer Peter B.
Published: November 2009

Purpose:

The aim of this work was to investigate the use of amorphous silicon electronic portal imaging devices (EPIDs) for regular quality assurance of linear accelerator asymmetric jaw junctioning.

Methods:

The method uses the beam central axis position on the EPID measured to subpixel accuracy found from two EPID images with 180° opposing collimator angles. Individual zero jaw position (“half‐beam blocked”) images are then acquired and the jaw position precisely determined for each using penumbra interpolation. The accuracy of determining jaw position with the EPID method was measured by translating a block (simulating a jaw) by known distances, using a translation stage, and then measuring each translation distance with the EPID. To establish the utility of EPID based junction dose measurements, radiographic film measurements of junction dose maxima/minima as a function of jaw gap/overlap were made and compared to EPID measurements. Using the method, the long‐term stability of zero jaw positioning was assessed for four linear accelerators over a 1–1.5 yr time period. The stability at nonzero gantry angles was assessed over a shorter time period.

Results:

The accuracy of determining jaw translations with the method was within 0.14 mm found using the translation stage [standard deviation (SD) of 0.037 mm]. The junction doses measured with the EPID were different from film due to the nonwater equivalent EPID scattering properties and hence different penumbra profile. The doses were approximately linear with gap or overlap, and a correction factor was derived to convert EPID measured junction dose to film measured equivalent. Over a 1 yr period, the zero jaw positions at gantry zero position were highly reproducible with an average SD of 0.07 mm for the 16 collimator jaws examined. However, the average jaw positions ranged from −0.7 to 0.9 mm relative to central axis for the different jaws. The zero jaw position was also reproducible at gantry 90° position with 0.1 mm SD variation with the mean jaw position offset from the gantry zero position consistently by 0.3–0.4 mm for the jaws studied.

Conclusions:

The EPID based method is efficient and yields more precise data on linear accelerator jaw positioning and reproducibility than previous methods. The results highlight that zero jaw positions are highly reproducible to a level much smaller than the displayed jaw resolution and that there is a need for better methods to calibrate the jaw positioning.
Computer‐assisted extraction of intracranial aneurysms on 3D rotational angiograms for computational fluid dynamics modeling
Authors: Chang Herng‐Hua , Duckwiler Gary R. , Valentino Daniel J. , Chu Woei Chyn
Published: November 2009

Purpose:

Three‐dimensional rotational angiography (3DRA) is an evolving imaging procedure from traditional digital subtraction angiography and is gaining much interest for detecting intracranial aneurysms. Computational fluid dynamics (CFD) modeling plays an important role in understanding the biomechanical properties and in facilitating the prediction of aneurysm rupture. A successful computational study relies on an accurate description of the vascular geometry that is obtained from volumetric images.

Methods:

The authors propose a new aneurysm segmentation algorithm to facilitate the study of CFD. This software combines a region‐growing segmentation method with the 3D extension of a deformable contour based on a charged fluid model. A charged fluid model essentially consists of a set of charged elements that are governed by the nature of electrostatics. The approach requires no prior knowledge of anatomic structures and automatically segments the vasculature after the end‐user selects a vessel section in a plane image.

Results:

Experimental results on 15 cases indicate that aneurysm structures were effectively segmented and in good agreement with manual delineation outcomes. In comparison with the existing methods, the algorithm provided a much higher overlap index with respect to the ground truth. Furthermore, the outcomes of the proposed approach achieved a clean representation of vascular structures that is advantageous for hemodynamics analyses.

Conclusions:

A new aneurysm segmentation framework in an attempt to automatically segment vascular structures in 3DRA image volumes has been developed. The proposed algorithm demonstrated promising performance and unique characteristics to adequately segment aneurysms in 3DRA image volumes for further study in computational fluid dynamics.
Singular value decomposition based computationally efficient algorithm for rapid dynamic near‐infrared diffuse optical tomography
Authors: Gupta Saurabh , Yalavarthy Phaneendra K. , Roy Debasish , Piao Daqing , Vasu Ram M.
Published: November 2009

Purpose:

A computationally efficient algorithm (linear iterative type) based on singular value decomposition (SVD) of the Jacobian has been developed that can be used in rapid dynamic near‐infrared (NIR) diffuse optical tomography.

Methods:

Numerical and experimental studies have been conducted to prove the computational efficacy of this SVD‐based algorithm over conventional optical image reconstruction algorithms.

Results:

These studies indicate that the performance of linear iterative algorithms in terms of contrast recovery (quantitation of optical images) is better compared to nonlinear iterative (conventional) algorithms, provided the initial guess is close to the actual solution. The nonlinear algorithms can provide better quality images compared to the linear iterative type algorithms. Moreover, the analytical and numerical equivalence of the SVD‐based algorithm to linear iterative algorithms was also established as a part of this work. It is also demonstrated that the SVD‐based image reconstruction typically requires operations per iteration, as contrasted with linear and nonlinear iterative methods that, respectively, require and operations, with “” being the number of unknown parameters in the optical image reconstruction procedure.

Conclusions:

This SVD‐based computationally efficient algorithm can make the integration of image reconstruction procedure with the data acquisition feasible, in turn making the rapid dynamic NIR tomography viable in the clinic to continuously monitor hemodynamic changes in the tissue pathophysiology.
T Cells Get the Nod
Authors: Gough Nancy R.
Published: November 2009

Nod2 functions within T cells to promote differentiation into T helper cells.
Dysbindin Function in Synaptic Homeostasis
Authors: Hurtley Stella M.
Published: November 2009

The dysbindin protein is required for the modulation of presynaptic neurotransmitter release in
Drosophila
.
In Vivo
Assessment of the Antimicrobial Activity of a Calcium-Deficient Apatite Vancomycin Drug Delivery System in a Methicillin-Resistant
Staphylococcus aureus
Rabbit Osteomyelitis Experimental Model
Authors: Amador G. , Gautier H. , Le Mabecque V. , Miegeville A. F. , Potel G. , Bouler J.-M. , Weiss P. , Caillon J. , Jacqueline C.
Published: November 2009

The antimicrobial activities of calcium-deficient apatite loaded with different concentrations (25, 100, and 500 μg/mg) of vancomycin as a filling biomaterial were evaluated in a methicillin-resistant
Staphylococcus aureus
(MRSA) rabbit acute osteomyelitis model. Bacterial counts in bone, bone marrow, and joint fluid samples treated with forms of the apatite were compared to those in tissue samples receiving a constant intravenous vancomycin infusion after 4 days. This study demonstrates that using a calcium-deficient apatite loaded with vancomycin dramatically decreases the bacterial counts in bone and marrow.
Population Pharmacokinetic Analysis of Vancomycin Using Serum Cystatin C as a Marker of Renal Function
Authors: Tanaka Akihiro , Aiba Tetsuya , Otsuka Takashi , Suemaru Katsuya , Nishimiya Tatsuya , Inoue Tomoyoshi , Murase Mitsuharu , Kurosaki Yuji , Araki Hiroaki
Published: November 2009

We determined the population pharmacokinetics of vancomycin (VAN) using the glomerular filtration rate (GFR) estimated from the serum cystatin C concentration. We examined the predictive performance of the trough serum VAN concentration for determination of the initial dose by using a new model for the analysis of the population pharmacokinetic parameters. Data for 86 patients were used to estimate the values of the population pharmacokinetic parameters. Analysis with a nonlinear mixed-effects modeling program was done by using a one-compartment model. Data for 78 patients were used to evaluate the predictive performance of the new model for the analysis of population pharmacokinetic parameters. The estimated GFR values determined by using Hoek's formula correlated linearly with VAN clearance (VAN clearance [ml/min] = 0.825 × GFR). The mean volume of distribution was 0.864 (liters/kg). The interindividual variability of VAN clearance was 19.8%. The accuracy of the prediction determined by use of the new model was statistically better than that determined by use of the Japanese nomogram-based model because the 95% confidence interval (−3.45 to −1.38) of the difference in each value of the mean absolute error (−2.41) did not include 0. Use of the serum cystatin C concentration as a marker of renal function for prediction of serum VAN concentrations may be useful.
Mechanism of Entecavir Resistance of Hepatitis B Virus with Viral Breakthrough as Determined by Long-Term Clinical Assessment and Molecular Docking Simulation
Authors: Mukaide Motokazu , Tanaka Yasuhito , Shin-I Tadasu , Yuen Man-Fung , Kurbanov Fuat , Yokosuka Osamu , Sata Michio , Karino Yoshiyasu , Yamada Gotaro , Sakaguchi Kohsaku , Orito Etsuro , Inoue Manami , Baqai Sumbella , Lai Ching-Lung , Mizokami Masashi
Published: November 2009

The mechanism by which entecavir resistance (ETVr) substitutions of hepatitis B virus (HBV) can induce breakthrough (BT) during ETV therapy is largely unknown. We conducted a cross-sectional study of 49 lamivudine (LVD)-refractory patients and 59 naïve patients with chronic hepatitis B. BT was observed in 26.8% of the LVD-refractory group during weeks 60 to 144 of ETV therapy. A line probe assay revealed ETVr substitutions only in the LVD-refractory group, i.e., in 4.9% of patients at baseline, increasing to 14.6%, 24.4%, and 44.8% at weeks 48, 96, and 144, respectively. Multivariate logistic regression analysis adjusted for age, gender, HBV DNA levels, and LVD resistance (LVDr) (L180M and M204V, but not M204I) indicated that T184 substitutions and S202G (not S202C) were a significant factor for BT (adjusted odds ratio [OR], 141.12, and 95% confidence interval [CI], 6.94 to 2,870.20; OR, 201.25, and 95% CI, 11.22 to 3608.65, respectively). Modeling of HBV reverse transcriptase (RT) by docking simulation indicated that a combination of LVDr and ETVr (T184L or S202G) was characterized by a change in the direction of the D205 residue and steric conflict in the binding pocket of ETV triphosphate (ETV-TP), by significantly longer minimal distances (2.2 Å and 2.1 Å), and by higher potential energy (−117 and −99.8 Kcal/mol) for ETV-TP compared with the wild type (1.3 Å; −178 Kcal/mol) and LVDr substitutions (1.5 Å; −141 Kcal/mol). Our data suggest that the low binding affinity of ETV-TP for the HBV RT, involving conformational change of the binding pocket of HBV RT by L180M, M204V plus T184L, and S202G, could induce BT.
Plasmodium falciparumMerozoite Surface Protein 1 (MSP-1)-MSP-3 Chimeric Protein: Immunogenicity Determined with Human-Compatible Adjuvants and Induction of Protective Immune Response
Authors: Mazumdar Suman , Mukherjee Paushali , Yazdani Syed Shams , Jain S. K. , Mohmmed Asif , Chauhan Virander Singh
Published: November 2009

A chimeric gene,MSP-Fu24, was constructed by genetically coupling immunodominant, conserved regions of the two leading malaria vaccine candidates,Plasmodium falciparummerozoite surface protein 1 (C-terminal 19-kDa region [PfMSP-119]) and merozoite surface protein 3 (11-kDa conserved region [PfMSP-311]). The recombinant MSP-Fu24protein was produced inEscherichia colicells and purified to homogeneity by a two-step purification process with a yield of ∼30 mg/liter. Analyses of conformational properties of MSP-Fu24using PfMSP-119-specific monoclonal antibody showed that the conformational epitopes of PfMSP-119that may be critical for the generation of the antiparasitic immune response remained intact in the fusion protein. Recombinant MSP-Fu24was highly immunogenic in mice and in rabbits when formulated with two different human-compatible adjuvants and induced an immune response against both PfMSP-119and PfMSP-311. Purified anti-MSP-Fu24antibodies showed invasion inhibition ofP. falciparum3D7 and FCR parasites, and this effect was found to be dependent on antibodies specific for the PfMSP-119component. The protective potential of MSP-Fu24was demonstrated byin vitroparasite growth inhibition using an antibody-dependent cell inhibition (ADCI) assay with anti-MSP-Fu24antibodies. Overall, the antiparasitic activity was mediated by a combination of growth-inhibitory antibodies generated by both the PfMSP-119and PfMSP-311components of the MSP-Fu24protein. The antiparasitic activities elicited by anti-MSP-Fu24antibodies were comparable to those elicited by antibodies generated with immunization with a physical mixture of two component antigens, PfMSP-119and PfMSP-311. The fusion protein induces a protective immune response with human-compatible adjuvants and may form a part of a multicomponent malaria vaccine.
Infection of Mast Cells with Live Streptococci Causes a Toll-Like Receptor 2- and Cell-Cell Contact-Dependent Cytokine and Chemokine Response
Authors: Rönnberg Elin , Guss Bengt , Pejler Gunnar
Published: November 2009

Mast cells (MCs) are strongly implicated in immunity toward bacterial infection, but the molecular mechanisms by which MCs contribute to the host response are only partially understood. We addressed this issue by examining the direct effects of a Gram-positive pathogen,Streptococcus equi, on bone marrow-derived MCs (BMMCs). Ultrastructural analysis revealed extensive formation of dilated rough endoplasmic reticulum in response to bacterial infection, indicating strong induction of protein synthesis. However, the BMMCs did not show signs of extensive degranulation, and this was supported by only slow release of histamine in response to infection. Coculture of live bacteria with BMMCs caused a profound secretion of CCL2/MCP-1, CCL7/MCP-3, CXCL2/MIP-2, CCL5/RANTES, interleukin-4 (IL-4), IL-6, IL-12, IL-13, and tumor necrosis factor alpha, as shown by antibody-based cytokine/chemokine arrays and/or enzyme-linked immunosorbent assay. In contrast, heat-inactivated bacteria caused only minimal cytokine/chemokine release. The cytokine/chemokine responses were substantially attenuated in Toll-like receptor 2-deficient BMMCs and were strongly dependent on cell-cell contacts between bacteria and BMMCs. Gene chip microarray analysis confirmed a massively upregulated expression of the genes coding for the secreted cytokines and chemokines and also identified a pronounced upregulation of numerous additional genes, including transcription factors, signaling molecules, and proteases. Together, the present study outlines MC-dependent molecular events associated with Gram-positive infection and thus provides an advancement in our understanding of how MCs may contribute to host defense toward bacterial insults.
Inertia effects in bed-load transport modelsThis paper is one of a selection of papers in this Special Issue in honour of Professor M. Selim Yalin (1925-2007).
Authors: Zech Y. , Soares-Frazão S. , Spinewine B. , Savary C. , Goutière L.
Published: November 2009

Inertia effects are seldom considered in morphological modeling, and most of the transport models were developed from laboratory experiments in steady uniform flow conditions. This paper considers first the hysteresis effects in transient flows between discharge, velocity, and bottom shear stress. These effects can be taken into account as far as the complete shallow-water equations are used. Secondly, inertia effects linked to the sediment response to acting forces are considered. Three types of models are investigated: (i) sediment movement instantaneously adapting to hydrodynamic changes, (ii) spatial or temporal lag laws to give space or time to the sediments to progressively reach the transport capacity, and (iii) a two-layer model, able to account for the inertia of the sediment layer. Finally, three examples are presented: a scour hole downstream of an apron, a jump over a mobile bed, and a dam-break wave. Inertia effects appear significant in the modeling, especially the latter case.
Effect of pulp mill effluent on the transport of suspended sediment in the Athabasca River near Hinton, Alberta, CanadaThis paper is one of a selection of papers in this Special Issue in honour of Professor M. Selim Yalin (1925–2007).
Authors: Krishnappan Bommanna G.
Published: November 2009

Field and laboratory measurements of the transport of the suspended sediment from the Athabasca River near Hinton, Alberta, Canada are described. The objective of these measurements was to examine the influence of pulp mill effluent entering the river from a nearby pulp mill on suspended sediment. The results of the field measurement showed that the effluent had significant impact on the transport of the sediment. Specifically, the effluent increased the deposition rates of the sediment and caused a substantial reduction of sediment concentrations in reaches downstream of the effluent outfall. The reduction in sediment concentrations and the concomitant sediment loads can only be attributed to the pulp mill effluent as there were no abrupt changes in the hydraulic characteristics of the river in the reach of interest. These observations were confirmed by laboratory experiments that were carried out using a rotating circular flume located at the National Water Research Institute in Burlington, Ontario, Canada. The findings of this study have implications for modelling suspended sediment transport in rivers receiving bleached pulp mill effluents.
Molecular and mechano-biology of collagen gel contraction mediated by human MG-63 cells: involvement of specific intracellular signaling pathways and the cytoskeleton
Authors: Parreno Justin , Hart David A.
Published: November 2009

Culture of human osteoblast-like MG-63 cells within collagen gels results in the generation of intrinsic stress. Release of such collagen gels from attachment results in gel contraction and enhanced MMP-1, MMP-3, and α2 integrin mRNA levels. To understand the potential role of microtubules and signaling pathways involved in MG-63 cell-mediated contraction and gene expression, cells were cultured in collagen gels. After 24 h collagen gels were released, then immediately treated with nocodazole or specific protein kinase inhibitors. Contraction was assessed, RNA isolated, and real-time PCR analysis performed. Treatment with high concentrations of a microtubule depolymerization agent, nocodazole, enhanced early contraction and led to elevated mRNA levels for MMP-3, whereas low concentrations inhibited contraction at later time points and did not affect mRNA levels. ROCK inhibitor treatment (Y27632) inhibited collagen gel contraction and led to depressed mRNA levels. The ERK1/2 inhibitor U0126 did not affect contraction, but treatment led to depressed MMP-1, MMP-3, and α2 mRNA levels. The p38MAPK inhibitor SB203580 modestly affected contraction, but did not affect mRNA levels. These results suggest the potential role of cytoskeletal integrity and multiple kinase signaling pathways in specific bone-remodeling events.
Calmodulin inhibition contributes to sensitize TRAIL-induced apoptosis in human lung cancer H1299 cells
Authors: Hwang Mi-kyung , Min Yong Ki , Kim Seong Hwan
Published: November 2009

Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) preferentially triggers apoptosis in tumor cells versus normal cells. However, TRAIL alone is not effective in treating TRAIL-resistant tumors. We evaluated the effect of 180 enzyme inhibitors on TRAIL-induced apoptosis in human lung cancer H1299 cells, and found fluphenazine-N-2-chloroethane (a calmodulin (CaM) antagonist) sensitized TRAIL-induced apoptosis. Interestingly, in the presence of TRAIL, it increased caspase-8 binding to the Fas-associated death domain (FADD), but decreased binding of FADD-like interleukin-1β-converting enzyme inhibitory proteins (FLIPs). Additionally, its combination with TRAIL inhibited Akt phosphorylation. These results were consistently observed in cells treated with CaM siRNA. We suggested the blockade of CaM could sensitize lung cancer cells to TRAIL-induced apoptosis in at least 2 ways: (i) it can activate death-inducing signaling complex mediated apoptosis by inhibiting TRAIL-induced binding of FLIP and TRAIL-enhanced binding of caspase-8 to FADD; (ii) it can inhibit Akt phosphorylation, consequently leading to decreased expression of anti-apoptotic molecules such as FLIP and members of the inhibitor of apoptosis protein family. This study suggests the combination of CaM antagonists with TRAIL may have the therapeutic potential to overcome the resistance of lung cancers to apoptosis.
Beyond structure, to survival: activation of Stat3 by cadherin engagement
Authors: Raptis Leda , Arulanandam Rozanne , Vultur Adina , Geletu Mulu , Chevalier Sébastien , Feracci Hélène
Published: November 2009

Cells in normal tissues or in tumors have extensive opportunities for adhesion to their neighbors and the importance of cell to cell contact in the study of fundamental cellular processes is beginning to emerge. In this review, we discuss recent evidence of dramatic changes in the activity of an important signal transducer found to be profoundly affected by cell to cell adhesion, the signal transducer and activator of transcription-3 (Stat3). Direct cadherin engagement, growth of cells to postconfluence, or formation of multicellular aggregates were found to induce a striking increase in the levels of Stat3 activity, Rac1/Cdc42, and members of the IL6 receptor family in different settings. This activation was specific to Stat3, in that the levels of the extracellular signal regulated kinase (Erk1/2), a signal transducer often coordinately activated with Stat3 by a number of growth factors or oncogenes, remained unaffected by cell density. Density-dependent Stat3 activation may play a key role in survival, and could contribute to the establishment of cell polarity. It is clear that at any given time the total Stat3 activity levels in a cell are the sum of the effects of cell to cell adhesion plus the conventional Stat3 activating factors present.
Ameliorating effects of cloperastine on dysfunction of the urinary bladder caused by cerebral infarction in conscious rats
Authors: Yamamoto Gen , Soeda Fumio , Shirasaki Tetsuya , Takahama Kazuo
Published: November 2009

We investigated the effects of the centrally acting antitussives dextromethorphan and cloperastine on urinary bladder dysfunction 24 h after cerebral infarction in rats using the cystometry technique. First, cystometrography was performed in conscious male Sprague–Dawley rats. Cerebral infarction was then induced by occlusion of the left middle cerebral artery. Twenty-four hours after cerebral infarction, the effect of each drug on micturition disorder was estimated for 5 parameters: bladder capacity, maximum voiding pressure, micturition latency, flow rate, and urethral resistance. Cerebral infarction markedly reduced bladder capacity, micturition latency, and flow rate and increased urethral resistance. After cerebral infarction, intravenous dosing of saline had no effect on these parameters. Dextromethorphan (20 mg/kg) and cloperastine (2.5 and 5.0 mg/kg) at antitussive effective doses significantly increased bladder capacity and micturition latency. Unlike dextromethorphan, cloperastine ameliorated decreases in flow rate and increases in urethral resistance caused by cerebral infarction. These results suggest that cloperastine may have therapeutic value for the treatment of disorders of the micturition reflex associated with cerebral infarction, and that the drug may become a base compound from which to develop more active drugs for such disorders.
Atorvastatin mediates increases in intralesional BAX and BAK expression in human end-stage abdominal aortic aneurysms
Authors: Schweitzer Morris , Mitmaker Benjamin , Obrand Daniel , Sheiner Nathan , Abraham Cherrie , Dostanic Stevan , Chalifour Lorraine E.
Published: November 2009

Chronic apoptosis activation may participate in abdominal aortic aneurysm (AAA) expansion. Statin treatment slows AAA progression independent of cholesterol lowering. We hypothesized that Atorvastatin treatment alters apoptosis protein expression and activation in AAAs. Protein was isolated from the central and distal portions of end-stage human AAA tissue obtained during surgical repair from non-statin (NST) and Atorvastatin-treated (AT) patients. Expression was compared using immunoblots. Bcl-2 expression was unchanged but Bak (4-fold, p < 0.013) and Bax (3-fold, p < 0.035) expression was increased in AT (n = 12) versus NST (n = 15) patients. No cytochrome c release or caspase 3 activation was detected and Clusterin, GRP78, and BNIP1 expression was similar in NST and AT samples. Bcl-2 and Bax cDNA sequences from AAA tissue (n = 10) and the general population were identical. Thus, the increase in Bax and Bak in AT-treated AAAs did not activate the mitochondria or endoplasmic reticulum mediated apoptosis pathways. Bcl-2, Bax, and Bak have non-apoptosis related functions that include maintenance of endoplasmic reticulum (ER), homeostasis, and adaptation to stress. We speculate that Atorvastatin-mediated increases in Bax and Bak may positively affect their non-apotosis related cell functions to account for the beneficial effect of statins to slow AAA expansion.
Behavioral avoidance of injured conspecific and predatory chemical stimuli by larvae of the aquatic caddisfly Hesperophylax occidentalis
Authors: Gall B. G. , Brodie, Jr. E. D.
Published: November 2009

Prey animals often encounter situations that hinder their ability to conduct normal fitness-enhancing behaviors. Mating and foraging are frequently interrupted by predator vigilance and avoidance, and antipredator behavior. Many caddisfly larvae build protective cases that are carried with them throughout the aquatic life cycle. However, they are still vulnerable to predation, yet it is unknown the extent caddisflies use chemical cues for predator recognition and avoidance. We exposed larval caddisfly Hesperophylax occidentalis (Banks, 1908) to predatory, conspecific, and heterospecific chemical cues to determine if caddisfly larvae can use chemical stimuli alone for predator recognition and avoidance. Exposure to predator and injured conspecific chemicals elicited significant decreases in activity, while exposure to injured and uninjured heterospecific chemicals yielded no significant change in activity. The extended latency to move following exposure to predator kairomones indicates larval caddisflies utilize chemical cues for predator recognition and avoidance, and a similar decrease in movement associated with exposure to injured conspecifics suggests the presence of a chemical alarm cue.
Do territorial male three-spined sticklebacks have sperm with different characteristics than nonterritorial males?
Authors: Côté J. , Blier P. U. , Caron A. , Dufresne F.
Published: November 2009

The three-spined stickleback ( Gasterosteus aculeatus aculeatus L., 1758) shows unequal energetic expenditure upon reproduction as some males defend territories and build nest (territorials: TM) where they spawn singly with females, whereas other males remain nonterritorial (NTM), do not build nests, and resort to sneaking fertilizations from nesting males. We examined the effects of reproductive strategy on various sperm parameters. Territorial status was assessed by introducing males in small wading pools and recording the number of males with a nest. Males from all pools were remixed and nesting status was reassessed. This allowed us to discriminate a group of males with repetitive territorial or nonterritorial behaviours (TM and NTM) or a “facultative” territorial behaviour (FM). TM had a significantly larger gonadosomatic index (GSI) than both FM and NTM. FM had a GSI that was significantly larger than NTM, but significantly smaller than TM. Sperm motility did not differ among males with different reproductive tactics. There were no significant differences in citrate synthase (CS) and pyruvate kinase (PK) activities among males with different status. Curiously, we found a significant negative relationship between CS and PK activities and total number of sperm.
AVERAGE VALUE OF SUM OF EXPONENTS OF RUNS IN A STRING
Authors: KUSANO KAZUHIKO , MATSUBARA WATARU , ISHINO AKIRA , SHINOHARA AYUMI
Published: November 2009

A substring w[i.j] in w is called a repetition of period p if w[k] = w[k + p] for any i ≤ k ≤ j - p. Especially, a maximal repetition, which cannot be extended neither to left nor to right, is called a run. The ratio of the length of the run to its period, i.e. [Formula: see text], is called an exponent. The sum of exponents of runs in a string is of interest. The maximal value of the sum is still unknown, and the current upper bound is 2.9n given by Crochemore and Ilie, where n is the length of a string. In this paper we show a closed formula which exactly expresses the average value of it for any n and any alphabet size, and the limit of this value per unit length as n approaches infinity. For binary strings, the limit value is approximately 1.13103. We also show the average number of squares in a string of length n and its limit value.
POLYNOMIAL HAMILTONIANS FOR QUANTUM PAINLEVÉ EQUATIONS
Authors: UENO YUICHI
Published: November 2009

Recently, a quantum version of Painlevé equations from the point of view of their symmetries was proposed by Nagoya. These quantum Painlevé equations can be written as Hamiltonian systems with a (noncommutative) polynomial Hamiltonian H J . We give a characterization of the quantum Painlevé equations by certain holomorphic properties. Namely, we introduce canonical transformations such that the Painlevé Hamiltonian system is again transformed into a polynomial Hamiltonian system, and we show that the Hamiltonian can be uniquely characterized through this holomorphic property.
FAITHFUL REPRESENTATIONS OF MINIMAL DIMENSION OF CURRENT HEISENBERG LIE ALGEBRAS
Authors: CAGLIERO LEANDRO , ROJAS NADINA
Published: November 2009

Given a Lie algebra 𝔤 over a field of characteristic zero k, let μ(𝔤) = min{dim π : π is a faithful representation of 𝔤}. Let 𝔥m be the Heisenberg Lie algebra of dimension 2m + 1 over k and let k [t] be the polynomial algebra in one variable. Given m ∈ ℕ and p ∈ k [t], let 𝔥m, p = 𝔥m ⊗ k [t]/(p) be the current Lie algebra associated to 𝔥m and k [t]/(p), where (p) is the principal ideal in k [t] generated by p. In this paper we prove that [Formula: see text].

We also prove a result that gives information about the structure of a commuting family of operators on a finite dimensional vector space. From it is derived the well-known theorem of Schur on maximal abelian subalgebras of 𝔤𝔩(n, k ).
A RIGIDITY THEOREM FOR QUATERNIONIC KÄHLER STRUCTURES
Authors: HATTORI KOTA
Published: November 2009

We study the moduli space of quaternionic Kähler structures on a compact manifold of dimension 4n ≥ 12 from a point of view of Riemannian geometry, rather than that of twistor theory. Then we obtain a rigidity theorem for quaternionic Kähler structures of nonzero scalar curvature by observing the moduli space.
EXPERIMENTAL STUDY AND LOGISTIC REGRESSION MODELING FOR MACHINE CONDITION MONITORING THROUGH MICROCONTROLLER-BASED DATA ACQUISITION SYSTEM
Authors: ZHANG JULIE , NIE HONG
Published: November 2009

Machine condition monitoring plays an important role in machining performance. A machine condition monitoring system will provide significant economic benefits when applied to machine tools and machining processes. By applying Taguchi design method, real-time pilot experimental study was conducted on a CNC machining center for monitoring the end mill cutting operations through the vibration data collection via a microcontroller-based data acquisition system. Featured machining signals were identified through data analyses and regression models were established that incorporates different combinations of featured machining signals and machining parameters in using logistic regression modeling approach. The onsite tests show that the developed logistic models including the featured machining signals can correctly distinguish worn and new cutting tools. Therefore, they can help construct decision-making mechanism for machine condition monitoring.
Blueprints for self-assembly
Authors: Anthes Gary
Published: November 2009

Researchers are using tools from information theory and computer science to facilitate the automatic creation of nanoscale structures.
Making automation work
Authors: Greengard Samuel
Published: November 2009

Today's automated systems provide enormous safety and convenience. However, when glitches, problems, or breakdowns occur, the results can be catastrophic.
Problem solvers
Authors: Hoffmann Leah
Published: November 2009

This year's Grace Hopper Celebration focused on using technology for social good.
Broadening participationOpening remarks
Authors: Ladner Richard E.
Published: November 2009

Highlighting efforts and providing the rationale to increase the participation and success of underrepresented groups in computing.
The profession of ITComputing's paradigm
Authors: Denning Peter J. , Freeman Peter A.
Published: November 2009

Trying to categorize computing as engineering, science, or math is fruitless; we have our own paradigm.
A threat analysis of RFID passports
Authors: Ramos Alan , Scott Weina , Scott William , Lloyd Doug , O'Leary Katherine , Waldo Jim
Published: November 2009

Do RFID passports make us vulnerable to identity theft?
Maximizing power efficiency with asymmetric multicore systems
Authors: Fedorova Alexandra , Saez Juan Carlos , Shelepov Daniel , Prieto Manuel
Published: November 2009

How do we develop software to make the most of the promise that asymmetric multicore systems use a lot less energy?
Visual passwords
Authors: Renaud Karen , De Angeli Antonella
Published: November 2009

Introduction

Users of computer systems are accustomed to being asked for passwords -- it is as universal as it is frustrating. In the past there was little tolerance for the problems experienced remembering passwords, and many users still remember, with embarrassment, having to go hat-in-hand to request a password change and being treated with disdain by a lofty administrator. Latterly there is more understanding of the problems experienced by users, especially since the "
password conundrum
" has reached epidemic proportions for Web users, who are asked for passwords with unrelenting predictability.

The problems with passwords are clear -- users cannot remember numbers of meaningless alphanumeric strings with ease. Hence, they react by choosing simple and predictable words or numbers related to their everyday life, and engaging in insecure practices, such as writing passwords down or sharing them. These practices cause a breach affecting even the most secure and protected network system. Hence the user is often called the weakest link of the security chain, with system administrators despairing of trying to maintain security with the weak link so often reaching breaking point. Users forgetting passwords has serious economical consequences for organizations.

Both academia and industry have been investigating alternatives to passwords, with varying degrees of success. One of the most well-known solutions is the biometric -- measurement of either behavioral or physiological characteristics of the end-user. This is obviously superior to the password because it removes the burden on the user's memory. So why don't we just switch to biometrics and give the poor user a break? There are some valid and hard-to-overcome reasons for the slow uptake of biometrics, but before we can discuss them we need to consider the mechanics of authentication.
Positive externality, increasing returns, and the rise in cybercrimes
Authors: Kshetri Nir
Published: November 2009

Introduction

The meteoric rise in cybercrime has been an issue of pressing concern to our society. According to Federal Bureau of Investigation (FBI), nine out of 10 U.S. companies experienced computer security incidents in 2005 which led to a loss of $67.2 billion. A survey conducted by IBM found that U.S. businesses worry more about cybercrimes than about physical crimes. Internet-related frauds accounted for 46% of consumer complaints made to the Federal Trade Commission (FTC) in 2005. Total losses of Internet fraud victims reporting to FTC increased from $205 million in 2003 to $336 million in 2005. In a July 2007 interview with
USA Today
, McAfee CEO reported that his company received 3,000--5,000 threat submissions per day from customers and 10% of them were new.

This paper offers an economic analysis to explain cybercrimes' escalation. We define cybercrimes as criminal activities in which computers or computer networks are the principal means of committing an offense. Examples include cyber-theft, cyber-trespass, cyber-obscenity, critical infrastructure attacks and cyber-extortions.
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The most notable features of the cybercrime environment include newness, technology and skill-intensiveness, and a high degree of globalization. Factors such as a wide online availability of hacking tools, information sharing in the cyber-criminal community, availability of experienced hackers' help to less skillful criminals and congestion in law enforcement systems produce externality effects within the cyber-criminal community as well as across society and businesses.

We focus on three positive or self-reinforcing feedback systems to examine increasing returns in cybercrime related activities. In this article, we first provide an overview of the positive feedback loops that reinforce cyber-criminals' behavior. Then, we describe mechanisms associated with externality in cybercrime related activities.