bluuebunny/crossref_metadata_2025 huggingface dataset:
Ratiometric imaging of calcium during ischemia-reperfusion injury in isolated mouse hearts using Fura-2
Authors: Venkataraman Raghav , Holcomb Mark R , Harder Rene , Knollmann Björn C , Baudenbacher Franz
Published: July 2012

Background

We present an easily implementable method for measuring Fura-2 fluorescence from isolated mouse hearts using a commercially available switching light source and CCD camera. After calibration, it provides a good estimate of intracellular [Ca2+] with both high spatial and temporal resolutions, permitting study of changes in dispersion of diastolic [Ca2+], Ca2+ transient dynamics, and conduction velocities in mouse hearts. In a proof-of-principle study, we imaged isolated Langendorff-perfused mouse hearts with reversible regional myocardial infarctions.

Methods

Isolated mouse hearts were perfused in the Landendorff-mode and loaded with Fura-2. Hearts were then paced rapidly and subjected to 15 minutes of regional ischemia by ligation of the left anterior descending coronary artery, following which the ligation was removed to allow reperfusion for 15 minutes. Fura-2 fluorescence was recorded at regular intervals using a high-speed CCD camera. The two wavelengths of excitation light were interleaved at a rate of 1 KHz with a computer controlled switching light source to illuminate the heart.

Results

Fura-2 produced consistent Ca2+ transients from different hearts. Ligating the coronary artery rapidly generated a well defined region with a dramatic rise in diastolic Ca2+ without a significant change in transient amplitude; Ca2+ handling normalized during reperfusion. Conduction velocity was reduced by around 50% during ischemia, and did not recover significantly when monitored for 15 minutes following reperfusion.

Conclusions

Our method of imaging Fura-2 from isolated whole hearts is capable of detecting pathological changes in intracellular Ca2+ levels in cardiac tissue. The persistent change in the conduction velocities indicates that changes to tissue connectivity rather than altered intracellular Ca2+ handling may be underlying the electrical instabilities commonly seen in patients following a myocardial infarction.
Inhibition of nitric oxide synthesis enhances leukocyte rolling and adhesion in human microvasculature
Authors: Hossain Mokarram , Qadri Syed M , Liu Lixin
Published: July 2012

Background

Nitric oxide (NO) is a multifunctional signaling molecule that regulates important cellular events in inflammation including leukocyte recruitment. Previous studies have shown that pharmacological inhibition of NO synthesis induces leukocyte recruitment in various in vitro and animal models. However, it is not known whether NO modulation has similar effects on leukocyte-endothelial cell interactions within the human microvasculature. The present study explored the effect of systemic L-NAME treatment on leukocyte recruitment in the SCID-hu mouse model.

Methods

Human skin xenografts were transplanted in SCID mice to study human leukocyte dynamics in human vasculature. Early events of human leukocyte recruitment in human vasculature were studied using intravital microscopy. NO synthesis was pharmacologically inhibited using NG-nitro-L-arginine methyl ester (L-NAME). Immunohistochemical analysis was performed to elucidate E-selectin expression in human xenograft skin. Human neutrophil-endothelial cell interactions were also studied in an in vitro flow chamber assay system. P- and E-selectin expression on cultured human umbilical vein endothelial cells (HUVECs) was measured using ELISA. Platelet-activating factor (PAF) synthesis was detected using a TLC-based assay.

Results

L-NAME treatment significantly enhanced the rolling and adhesion of human leukocytes to the human vasculature. Functional blocking of P- and E-selectins significantly inhibited rolling but not adhesion induced by inhibition of NO synthesis. Systemic L-NAME treatment enhanced E-selectin expression in human xenograft skin. L-NAME treatment significantly enhanced P- and E-selectin expression on HUVECs. L-NAME treatment did not significantly modify neutrophil rolling or adhesion to HUVECs indicating that L-NAME−induced subtle P- and E-selectin expression was insufficient to elicit dynamic neutrophil-HUVEC interactions in vitro. Moreover, synthesis of endothelial-derived PAF was not significantly modified by L-NAME treatment. These results point to the accelerated leukocyte recruitment in human vasculature following suppression of NO synthesis, effects that are mediated by P- and E-selectins. The findings are, however, not supported by the in vitro data.

Conclusion

Inhibition of endogenous NO triggers early events of human leukocyte recruitment in human vasculature, involving complex cellular or molecular mechanisms in addition to P- and E-selectin-mediated leukocyte rolling.
Mizoguchi-Takahashi-type theorems in tvs-cone metric spaces
Authors: Shatanawi Wasfi , Rajić Vesna Ćojbašić , Radenović Stojan , Al-Rawashdeh Ahmed
Published: July 2012

In this paper, the concepts of a set-valued contraction of Mizoguchi-Takahashi type in the context of topological vector space (tvs)-cone metric spaces are introduced and a fixed point theorem in the context of tvs-cone metric spaces with respect to a solid cone is proved. We obtained results which extend and generalize the main results of S. H. Cho with J. S. Bae, Mizoguchi with Takahashi and S. B. Nadler Jr. Two examples are given to illustrate the usability of our results.

2010 MSC: 47H10, 54H25.
Enhancer of zeste homologue 2 (EZH2) is a reliable immunohistochemical marker to differentiate malignant and benign hepatic tumors
Authors: Hajósi-Kalcakosz Szofia , Dezső Katalin , Bugyik Edina , Bödör Csaba , Paku Sándor , Pávai Zoltán , Halász Judit , Schlachter Krisztina , Schaff Zsuzsa , Nagy Péter
Published: July 2012

Background

The immunohistochemical demonstration of Enhancer of zeste homologue 2 (EZH2) proved to be a useful marker in several tumor types. It has been described to distinguish reliably hepatocellular carcinomas from liver adenomas and other benign hepatocellular lesions. However, no other types of malignant liver tumors were studied so far.

Methods

To evaluate the diagnostic value of this protein in hepatic tumors we have investigated the presence of EZH2 by immunohistochemistry in hepatocellular carcinomas and other common hepatic tumors.

EZH2 expression was examined in 44 hepatocellular carcinomas, 23 cholangiocarcinomas, 31 hepatoblastomas, 16 other childhood tumor types (rhabdomyosarcoma, neuroblastoma, Wilms’ tumor and rhabdoid tumor), 17 metastatic liver tumors 24 hepatocellular adenomas, 15 high grade dysplastic nodules, 3 biliary cystadenomas, 3 biliary hamartomas and 3 Caroli’s diseases.

Results

Most of the malignant liver tumors were positive for EZH2, but neither of the adenomas, cirrhotic/dysplastic nodules, reactive and hamartomatous biliary ductules stained positively.

Conclusions

Our immunostainings confirm that EZH2 is a sensitive marker of hepatocellular carcinoma, but its specificity is very low, since almost all the investigated malignant liver tumors were positive regardless of their histogenesis. Based on these results EZH2 is a sensitive marker of malignancy in hepatic tumors. In routine surgical pathology EZH2 could be most helpful to diagnose cholangiocarcinomas, because as far as we know this is the first marker to distinguish transformed and reactive biliary structures. Although hepatoblastomas also express EZH2, the diagnostic significance of this observation seems to be quite limited whereas, the structurally similar, other blastic childhood tumors are also positive.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1173195902735693
Cardiac tamponade: contrast reflux as an indicator of cardiac chamber equalization
Authors: Nauta Foeke Jacob Harmen , Borstlap Wernard Aat Antoine , Stella Michael , Khalpey Zain
Published: July 2012

Background

Traumatic hemopericardium remains a rare entity; it does however commonly cause cardiac tamponade which remains a major cause of death in traumatic blunt cardiac injury.

Objectives

We present a case of blunt chest trauma complicated by cardiac tamponade causing cardiac chamber equalization revealed by reflux of contrast.

Case report

A 29-year-old unidentified male suffered blunt chest trauma in a motor vehicle collision. Computed tomography (CT) demonstrated a periaortic hematoma and hemopericardium. Significant contrast reflux was seen in the inferior vena cava and hepatic veins suggesting a change in cardiac chamber pressures. After intensive treatment including cardiac massage this patient expired of cardiac arrest.

Conclusion

Reflux of contrast on CT imaging can be an indicator of traumatic cardiac tamponade.
The hybrid approach for the surgical treatment of lone atrial fibrillation: One-year results employing a monopolar radiofrequency source
Authors: La Meir Mark , Gelsomino Sandro , Lorusso Roberto , Lucà Fabiana , Pison Laurant , Parise Orlando , Wellens Francis , Gensini Gian Franco , Maessen Jos
Published: July 2012

Background

The hybrid technique combines a mono or bilateral epicardial approach with a percutaneous endocardial ablation in a single-step procedure. We present our early results with this technique employing a monopolar radiofrequency source through a right thoracoscopy in patients with lone atrial fibrillation (LAF).

Methods

Between June 2009 and December 2010 nineteen consecutive patients (mean 60.8 ± 8.6 years, 84.2% male) underwent right unilateral minimally invasive hybrid procedure for LAF at our Institution. Ten patients (52.6.6%) had long-standing persistent AF while four (21.1%) had persistent and five (26.3%) paroxysmal AF. All patients were followed-up according the Heart Rhythm Society/European Heart Rhythm Association/European Cardiac Arrhythmia Society (HRS/EHRA/ECA) and Society of Thoracic Surgeon (STS) guidelines.

Results

There were neither early nor late deaths. It was possible to complete all the procedures as planned without any conversion to cardiopulmonary bypass. No patient died during the follow up. At one year, 7/19 (36.8%) patients were in sinus rhythm with no episode of AF and off antiarrhythmic drugs (AAD). Time-related prevalence of postoperative AF peaked at 44.4% (41.3–47.4) at two weeks, was 30.4% (27.3–34.9) at three months, fell to 14.2% (11.6–18.1) by 6 months and was 13.3% (11.0–17.4) at 12 months Among patients with long-standing persistent (LSP) AF, 20% (2/10) were in Sinus rythm and off AAD. One-year success rates were 50% (2/4) in persistent and 60% (3/5) in paroxysmal AF. At 12 months estimated prevalence of antyarrhythmic drugs and Warfarin use were 26% (22.4–33.1) and 48% (37.2–53.2), respectively.

Conclusions

One year results combining the percutaneous endocardial with the right thoracoscopic epicardial technique were, in our experience, not satisfactory, particularly in patients with LSP and persistent AF. Our findings need to be confirmed by larger studies.
Implementation of a secure genome sequence search platform on public cloud-leveraging open source solutions
Authors: Saxena Vikas , Doddavula Shyam Kumar , Jain Akansha
Published: July 2012

With looming patent cliffs, resulting in no patent protections for several block buster drugs, several Life sciences organizations are looking at ways to reduce the costs of drug discovery. They are looking to change business models from having all drug discovery activities being done in-house to a more economical collaborative innovation model by forming ecosystems through consortiums and alliances with several other partners to collaborate especially in the pre-competitive areas of drug discovery. They are considering leveraging cloud computing platforms to create the collaborative drug discovery platforms needed to support these new drug discovery models. Another area of focus is to improve the success rate of drug discovery by creating more complex computer models and performing more data intensive simulations. Next generation sequence sequencers are also providing unprecedented amounts of data to work with. Cloud computing has proven to be scalable and capable of meeting the computation needs in life sciences domain but a key inhibitor has been security concerns. This paper is an extension of an earlier paper we had written that describes how to leverage a public cloud to build a scalable genome sequence search platform to enable secure collaboration among multiple partners. This paper describes a few additional techniques and open source solutions that can be leveraged to address security concerns while leveraging public cloud platforms for collaborative drug discovery activities.
Understanding Patients' Attitudes Toward Communication About the Cost of Cancer Care
Authors: Bullock Andrea J. , Hofstatter Erin W. , Yushak Melinda L. , Buss Mary K.
Published: July 2012

Patients' comfort with and desire to discuss cancer costs exceed those of oncologists, suggesting a need to educate oncologists on this important topic.
Adherence to Clinical Practice Guidelines for Adjuvant Chemotherapy for Colorectal Cancer in a Canadian Province: A Population-Based Analysis
Authors: Rayson Daniel , Urquhart Robin , Cox Martha , Grunfeld Eva , Porter Geoff
Published: July 2012

A number of factors influence adherence to adjuvant chemotherapy clinical practice guidelines for colorectal cancer and should be incorporated in future work as novel regimens enter clinical practice.
Persistence of circannual rhythms under constant periodic and aperiodic light conditions: sex differences and relationship with the external environment
Authors: Budki Puja , Rani Sangeeta , Kumar Vinod
Published: July 2012

The timing and duration of gonadal phases in the year indicates that breeding cycles are regulated by endogenous mechanisms. The present study on tropical Spotted Munia (Lonchura punctulata) investigates whether such mechanisms are based on circannual rhythms, and whether circannual rhythms between sexes differ in their relationship with the light environment. Birds were subjected to 12 h light per day (12L:12D), alternate days of light and darkness (24L:24D, LL/DD) and continuous light (LL), with L= 22 lux and D = <1 lux, for 28 months (mo) at constant temperature (18±1°C). Groups kept on natural day lengths (NDL) served as controls. Measurement of body mass, gonads, and molts of the primary wing feathers and body plumage at regular intervals showed that birds underwent repeated cycles in gonads and molt, but not in the body mass. In NDL, gonadal phases in both sexes cycled with 12 mo periods. In other conditions, males cycled with similar periods of about 11 mo, but females cycled with relatively large period variations, about 10 to 13 mo. Gonadal recrudescence – regression phase was longer in males than in females and, in both sexes, in the second year as compared to the first year. The molt of wing primaries was more closely coupled to gonadal maturation in groups on NDL and 12L:12D than in groups on LL and LL/DD, but this relationship drifted apart in the second year. Body plumage molts were relatively more highly variable in both the frequency and pattern. It is suggested that annual breeding cycle in spotted munia is regulated by the self-sustained circannual rhythms, which probably interact with the annual photoperiodic cycle to synchronize breeding cycles to calendar year. Both sexes seem to have independent timing strategies, but females appear to share a greater role in defining the reproductive season in relation with the environment.
Vibrational playback by means of airborne stimuli
Authors: Rebar Darren , Höbel Gerlinde , Rodríguez Rafael L.
Published: July 2012

Substrate-borne vibrational communication is a common form of communication in animals. Current contact-based playback methods limit the number of substrates that can be stimulated simultaneously and potentially change the transmission properties of the substrate. Here, we explore a solution to these limitations by broadcasting airborne stimuli onto plant substrates in an attempt to impart vibrational playbacks. We demonstrate that one can effectively compensate for the filtering properties of any individual plant across a range of frequencies. We then address how well both compensated broad-band and pure-tone stimuli for one plant individual apply to other individuals across days. Variation within and between plants was similar across the range tested, but was quite variable at certain frequencies. Focusing on a subset of this range, at low frequencies responses were flat across days and pure-tone frequency stimuli in this range were consistently transmitted despite repositioning of plants relative to the loudspeaker. Our results present a potential solution to researchers interested in exposing large samples of individuals to vibrational signals, but also highlight the importance of validating the use of airborne stimuli as vibrational playbacks to the particular substrate type and frequency range of interest.
Novel monoclonal antibody recognizing triglyceride-rich oxidized LDLs associated with severe liver disease and small oxidized LDLs in normal subjects
Authors: Sakurai Toshihiro , Ichikawa Ayako , Furukawa Hiroyuki , Wada Norio , Nagasaka Atsushi , Takahashi Yuji , Fujikawa Masato , Ikuta Akiko , Furumaki Hiroaki , Shiga Maiko , Shimizu Chikara , Hui Shu-Ping , Jin Shigeki , Takeda Seiji , Fuda Hirotoshi , Nagasaka Hironori , Kobayashi Seiichi , Chiba Hitoshi
Published: July 2012

Background

Triglyceride-rich low-density lipoproteins (TG-rich LDLs) in the plasma of patients with severe liver disease are reported to change macrophages into foam cells in vitro.

Methods

Male BALB/c mice were immunized with TG-rich LDLs isolated from the plasma of a patient with severe liver disease. The resulting monoclonal antibody (G11-6) was used in a sandwich enzyme-linked immunosorbent assay (ELISA) in combination with polyclonal anti-apolipoprotein B antibodies. The time course of copper-mediated LDL oxidation was monitored using this ELISA. The results were compared with those of the two commercial ELISAs for oxidized LDLs using DLH or ML25, thiobarbituric acid reactive substances and the optical absorbance for the conjugated dienes generated in lipid peroxides. Furthermore, the lipoprotein fractions separated by gel filtration were tested with this ELISA in healthy volunteers ( n = 11) and patients ( n = 3) with liver disease.

Results

G11-6 reacted with oxidized LDLs during only the early phase of copper oxidation, being distinct from the other monoclonal antibodies and methods. G11-6 was confirmed to react with TG-rich LDLs in patients, while it reacted with small LDL particles in normal controls.

Conclusions

The monoclonal antibody G11-6 is useful for detecting oxidized small LDLs in normal controls and oxidized TG-rich LDLs in patients with severe liver disease.
Antioxidant and renoprotective effects of paricalcitol on experimental contrast-induced nephropathy model
Authors: Ari E , Kedrah A E , Alahdab Y , Bulut G , Eren Z , Baytekin O , Odabasi D
Published: July 2012

Objectives: The aim of the study was to assess the effect of paricalcitol on the experimental contrast-induced nephropathy (CIN) model. We hypothesised that paricalcitol may prevent CIN.

Methods: 32 Wistar albino rats were divided into four groups (n=8 each): control group, paricalcitol group, CIN group and paricalcitol plus CIN group. Paricalcitol (0.4 µg kg–1 day–1) was given intraperitoneally for 5 consecutive days prior to induction of CIN. CIN was induced at day 4 by intravenous injection of indometacin (10 mg kg–1), Nω-nitro-l-arginine methyl ester (L-NAME, 10 mg kg–1) and meglumine amidotrizoate (6 ml kg–1). Renal function parameters, oxidative stress biomarkers, histopathological findings and vascular endothelial growth factor (VEGF) immunoexpression were evaluated.

Results: The paricalcitol plus CIN group had lower mean serum creatinine levels (p=0.034) as well as higher creatinine clearance (p=0.042) than the CIN group. Serum malondialdehyde and kidney thiobarbituric acid-reacting substances levels were significantly lower in the paricalcitol plus CIN group than in the CIN group (p=0.024 and p=0.042, respectively). The mean scores of tubular necrosis (p=0.024), proteinaceous casts (p=0.038), medullary congestion (p=0.035) and VEGF immunoexpression (p=0.018) in the paricalcitol plus CIN group were also significantly lower.

Conclusion: This study demonstrates the protective effect of paricalcitol in the prevention of CIN in an experimental model.
Lower extremity and pelvic stress fractures in athletes
Authors: Liong S Y , Whitehouse R W
Published: July 2012

Stress fractures occur following excessive use and are commonly seen in athletes, in whom the lower limbs are frequently involved. Delayed diagnosis and management of these injuries can result in significant long-term damage and athlete morbidity. A high index of suspicion may facilitate diagnosis, but clinical presentation may be non-specific. In this regard, imaging in the form of plain radiograph, CT, MRI and bone scintigraphy may be of value. This article reviews the incidence, presentation, radiological findings and management options for athletes with stress fractures of the lower limb.
An Experimental Study on a Culvert Buried in Granular Soil Subjected to Vehicle Loads
Authors: Bian Xuecheng , Tang Xiaowu , Shen Wenming , Ling Daosheng , Chen Yunmin
Published: July 2012

To understand the performance of culverts buried in the granular soil under heavy vehicle loads, both experimental and numerical studies are conducted. Full-scale model tests with tire loads applied at different locations are carried out to obtain experimental data, and numerical simulation using 3D finite element method is performed to predict the culvert responses and soil distribution due to the same load distribution. Comparisons of the model test results with the computed responses are made in terms of soil pressure above the culvert crown, culvert structure's strain, and culvert deflection. The model test results indicate that the buried concrete culverts embedded with compacted aggregate perform good behavior without structural distress. Both numerical analyses and model tests show that the vehicle loads transferred to culvert crown decrease rapidly with the thickness of fill over the culvert. Based on the model tests and numerical analyses, the cover depth of 1.0 m at least is suggested for prefabricated concrete culverts.
De-Bonding Detection on a CFRP Laminated Concrete Beam Using Self Sensing-Based Multi-Scale Actuated Sensing with Statistical Pattern Recognition
Authors: Lee Changgil , Park Seunghee
Published: July 2012

This paper reports a novel structural health monitoring (SHM) technique for detecting de-bonding defects between a concrete beam structure and a CFRP (Carbon Fiber Reinforced Polymer) sheet attached to the concrete surface. To achieve this purpose, a multi-scale actuated sensing system with a self-sensing circuit using piezoelectric active sensors was applied to a CFRP laminated concrete beam structure. In the self-sensing based multi-scale actuated sensing system, a wide frequency-band structural response from the self-sensed impedance measurements and a specific frequency-induced structural wavelet response from the self-sensed guided wave measurement were utilized to localize the de-bonding defects. Furthermore, in order to quantify the de-bonding levels, the supervised learning-based statistical pattern recognition was implemented by composing a two-dimensional (2D) plane using the damage indices extracted from the impedance and guided wave features. The different levels of de-bonding defects inflicted artificially on the CFRP laminated concrete beam structure were investigated to confirm the effectiveness of the proposed SHM approach.
Modal Frequency Identification of Stay Cables with Ambient Vibration Measurements Based on Nontarget Image Processing Techniques
Authors: Chen Chien-Chou , Tseng Hong-Zeng , Wu Wen-Hwa , Chen Chi-Hong
Published: July 2012

Conventional sensors, such as the accelerometers and velocimeters, have been generally adopted to conduct the vibration measurements of stay cables for the identification of their dynamic parameters. Even though these contact sensors are able to obtain accurate measurements, the installation of such devices may require substantial efforts. A simple digital videogrammetric technique without using any artificial target is developed in this study to perform the ambient vibration measurements of stay cables for the subsequent identification of cable frequencies. This method significantly simplifies the image processing procedures by exploiting the straight boundary of cable to determine the midpoint of its edge line for serving as a convenient pseudo target. Demonstrated by the on-site measurements for three different cables selected from Chi-Lu Bridge, it is shown that this nontarget technique equipped with a customer grade camcorder and an ordinary tripod placed on the bridge deck can attain the same order of accuracy for cable frequency identification as that of high-resolution velocimeters. Both the vertical and transverse displacements of cable were measured under the ambient vibration amplitudes in the order of 0.5 mm and 0.2 mm, respectively. Based on this study, it is proved that the practical application of a nontarget videogrammetric technique to the cables of long-span cable-stayed bridges is not only feasible but also advantageous in many aspects.
Design of thermal stress restrained testing machine for measurement of low temperature cracking in asphalt concrete
Authors: Qadir Adnan
Published: July 2012

Thermal Stress Restrained Testing Machine (TSRST) is used for measurement of thermal stresses produced during testing of specimen at low temperatures. Though this machine has long been in practice by many researchers around the world, no consensus, however, reached on the specification of a standard testing machine. Researchers from different institutions are still coming with their own design of test setup and procedures to perform this test. This would mean that there might not be one manufacturer around the world who may have the capability to produce the machine on regular basis, or this can be put in this word that a TSRST designed is not patented yet. The contents presents in this paper discusses the modified version of one such machine. It is envisaged that the changes made in the TSRST equipment would improve the reliability of measuring thermally induced stresses in asphalt concrete specimen in the laboratory. This in turn will result in providing reliable solution to control low temperature cracking in asphalt pavement.
An Interactive 3-Dimensional Database Applied to the Conservation of a Painted Chapel
Authors: Vallet Jean-Marc , De Luca Livio , Feillou Marie , Guillon Odile , Pierrot-Deseilligny Marc
Published: July 2012

Matteo Giovannetti's frescoes (1355–1356) which decorate the Innocent VI chapel of La Chartreuse du Val des Bénédictins (Villeneuve-lez-Avignon, France) are very sensitive to the alteration. They need a new restoration campaign. Because of the geometrical complexity of the place, the environment and the involved degradation mechanisms, a good conservation management of these murals is essential. Therefore, an interactive 3- dimensional spatial database, including dated data was developped. Architectural measurements, digital scientific documentation were gathered. A historical documentation including restoration acts, used restoration products has been collected. Last, the paintings degradations, up-to-date deterioration patterns description and conservation state diagnosis of these wall paintings including a deterioration mapping are monitored. Results of the physical and chemical analyses of painting, restoration techniques and deterioration products are also integrated. The entire collected and interactive database will be available for conservation managers and researchers within the next three years.
An Enhanced On-Line Service for 3D Model Construction from Photographs
Authors: Tingdahl David , Van Luc Gool
Published: July 2012

We present a web service for image based 3D reconstruction. The system allows a cultural heritage professional to easily create a 3D model of a scene or object out of images taken from different viewpoints. The user uploads the images to our server on which all processing takes place, and the final result can be downloaded upon completion. Any consumer-class digital camera can be used, and the system is free to use for non-commercial purposes. The service includes a number of innovations to greatly simplify the process of taking pictures suitable for reconstruction. In particular, we are able to construct models of planar scenes and from photographs shot using a turntable, and at varying zoom levels. Although the first two may seem like particularly simple cases, they cause some mathematical issues with traditional self-calibration techniques. We handle these cases by taking advantage of a new automatic camera calibration method that uses meta-data stored with the images. For fixed-lens camera setups, we can also reuse previously computed calibrations to support otherwise degenerate scenes. Furthermore, we can automatically compute the relative scale and transformation between two reconstructions of the same scene, merging two reconstructions into one. We demonstrate the capabilities of the system by two case studies: turntable reconstruction of various objects and the reconstruction of a cave, with walls and roof integrated into a complete model.
Tools for Virtual Reassembly of Fresco Fragments
Authors: Brown Benedict , Laken Lara , Dutré Philip , Van Gool Luc , Rusinkiewicz Szymon , Weyrich Tim
Published: July 2012

The process of reassembling fragmented wall paintings is currently prohibitively time consuming, limiting the amount of material that can be examined and reconstructed. Computer-assisted technologies hold the promise of helping humans in this task, making it possible to digitize detailed shape, color, and surface relief information for each fragment. The data can be used for documentation, visualization (both on- and off-site), virtual restoration, and to automatically propose matches between fragments. Our focus in this paper is on improving the workflow, tools, and visualizations, as they are used by archaeologists and conservators to scan fragments and find matches. In particular, we evaluate the system's performance and user experience in ongoing acquisition and matching work on material from a Roman excavation in Tongeren, Belgium. Compared to prior systems, we can acquire fragments approximately 10 times faster, and support a wider range of fragment sizes (from 1 cm to 20 cm in diameter).
Resource Allocation for Homeland Defense: Dealing with the Team Effect
Authors: Samuel Andrew , Guikema Seth D.
Published: July 2012

The federal government's allocation of resources for defense against potential attacks generally involves depending on a multitiered organization consisting of federal, state, and local agencies for information on the risks faced in their jurisdictions and the costs and benefits of defensive actions they may take. These agencies then receive resources, ideally based on the collectively reported risks and resource needs. With private information about local risks and defensive actions and limited resources at the federal level, there are ample opportunities for agencies to take advantage of such a system for their benefit. This yields a suboptimal allocation of limited defensive resources. In this paper we describe this allocation problem formally as a game between a single principal (e.g., Congress) and agents representing more local agencies. This differs substantially from the treatment of the attacker–defender problem in the literature, where the defender is treated as a single, unified decision maker. We show that ignoring the within-team defender interactions in modeling the attacker–defender game leads to a suboptimal resource allocation. Existing results from agency theory are applied to this problem together with new results and insights into the interactions between an attacker and a multilevel defender.
Selection at the Gate: Difficult Cases, Spillovers, and Organizational Learning
Authors: Stan Mihaela , Vermeulen Freek
Published: July 2012

We analyze longitudinal data on British fertility clinics to examine the impact of “selection at the gate,” i.e., the attempts of organizations to improve the success rate of their output by selecting promising cases as input. In contrast to what might be expected, we argue that more stringent input selection is likely to lead to lower overt performance compared with those firms that admit difficult cases, because the latter develop steeper learning curves. That is, difficult cases enable greater learning from prior experience because they promote experimentation, communication among various actors, and the codification of new knowledge. Our results confirm this prediction and provide clear evidence that organizations with more difficult cases in their portfolios gradually begin to display performance figures that compare favorably with those of firms that do select at the gate.
Financial Slack, Strategy, and Competition in Movie Distribution
Authors: Natividad Gabriel
Published: July 2012

Organizations that enjoy some slack are believed to make good use of it in their strategic decisions. Using panel data on firms in the U.S. film distribution industry between 1985 and 2007, this article examines how financial slack affects the volume of new product introductions, the competitive strategies for those releases, and their economic performance. Unexpectedly successful “sleeper” films are exploited as a source of exogenous financial slack in the econometric analysis. The results suggest that unexpected financial slack leads to more product introductions, less marketing support for the new products, and no improvement in performance. These findings are consistent with an attribution process in which managers attempt to replicate extraordinary success even if it is largely random, providing real-world evidence of a mechanism recently developed in theory and laboratory research.
The Sustainable Humanities
Authors: Lemenager Stephanie , Foote Stephanie
Published: July 2012

Any discussion of how the humanities can contribute to sustainability or how the humanities are sustainable must begin with what critics of the sustainability concept have called its cultural deficit: academic humanists and artists have not been central to discussions of what sustainability is and might be. Sustainability is most commonly understood in economic terms, as production that respects ecological carrying capacities. Because the sustainability concept is “squishy,” in Bill McKibben's words, it invariably drifts toward the more pragmatic project of sustainable development, the goal of which is keeping modernization viable—a goal dubious to many environmentalists as well as to cultural critics (102). In an era when the rhetoric of crisis dominates public conversation about political, social, educational, and environmental affairs, the termsustainabilitycan seem anemic. Its emphasis on long-term planning and stewarding of resources has none of the dramatic appeal of apocalyptic visions of a world in which all human and natural ecologies are in collapse. For many environmental critics, it is a term that in some sense fails to account for the necessity of drastic changes in how resources are protected, much less distributed, and it relies too heavily on protecting the very state of affairs that got us into trouble in the first place. For its critics, and even for its reluctant supporters, it is a term about managing anxieties that shuttle between local and global concerns, individual and corporate responsibilities.
After Sustainability
Authors: Mentz Steve
Published: July 2012

It seemed like a good idea while it lasted, but we should have known it could not last. the era of sustainability is over. behind our shared cultural narratives of sustainability sits a fantasy about stasis, an imaginary world in which we can trust that whatever happened yesterday will keep happening tomorrow. It's been pretty to think so, but it's never been so. In literary studies, we name this kind of fantasypastoral.Such a narrative imagines a happy, stable relation between human beings and the nonhuman environment. It seldom rains, mud doesn't clog our panpipes, and our sheep never run away while swains sing beautiful songs to coy shepherdesses. In this sustainable green world, complicated things fit into simple packages, as literary criticism has recognized, from William Empson's “pastoral trick” (115) to Greg Gerrard's “pastoral ecology” (56–58). This green vision provides, in Gerrard's phrase, a “stable, enduring counterpoint to the disruptive energy and change of human societies” (56). That's the dream toward which sustainability entices us. To be sustainable is to persist in time, unchanged in essence if not details. That's not the human experience of the nonhuman world. Remember the feeling of being wet, like King Lear, “to the skin” (Mentz, “Strange Weather”). Changing scale matters, and local variation does not preclude global consistency, but the feeling of the world on our skin is disruptive. Our environment changes constantly, unexpectedly, often painfully.
Rudolph Fisher's Missing Story “The Shadow of White”: A Study in the Transformation of Race Consciousness
Authors: Fisher Rudolph , Rothenberg Molly Anne
Published: July 2012

During the nine years of his writing career, rudolph fisher published two novels as well as fifteen short stories and won Crisis magazine's Amy Spingarn Prize for fiction. He also published two scientific articles and a much anthologized essay, while writing two plays, a revue (with Langston Hughes), and eight other stories unpublished in his time. Seven of the unpublished stories were collected after his death, but one simply disappeared. In May 1925 Fisher submitted his only copy of “The Shadow of White” to Survey Graphic at the invitation of its editor, Paul Kellogg, whom he had met at that year's Opportunity dinner. Thirteen months after the submission, Kellogg offered eighty dollars for the story and said he hoped to publish it in 1926–27. Yet the story never appeared.
Interactive on-line resources for training forensic engineers
Authors: James Malcolm N.
Published: July 2012

Analysing engineering failures to determine causes, mechanisms and routes to avoid or mitigate future problems is often relatively straightforward. However, in multifaceted situations, or with complex structures, the exercise of forensic engineering can be rather more difficult. Alongside the potential interdisciplinary complexity of failure analysis, which is an important subset of the field of forensic engineering, there are significant issues in the communication of learning about failure and in the forensic training of engineers. From the viewpoint of failures experienced in mechanical and metallurgical engineering, this paper explores several current ideas related to definitions of failure, and ways of analysing and communicating learning about the cause–action–result sequence of events in a failure scenario. The paper also outlines the web-based resources developed by the author to support forensic training of undergraduate mechanical engineering students and continuing professional development of working engineers.
The flexural stress-strain relationship of concrete confined by rectangular transverse reinforcement
Authors: Soliman M. T. M. , Yu C. W.
Published: July 2012

Summary

To understand the plastic deformation capacity of critical regions reinforced with longitudinal and transverse reinforcement, it was felt that the stress-strain relationship of bound concrete in flexure must first be established. Sixteen specimens were tested in a specially constructed testing frame under the action of a major and a minor load. The stress-strain relationship for the concrete was obtained by an approach similar to that used by Hognestad, Hanson and McHenry in conjunction with a special graphical interpolation technique. A generalized relationship was finally developed expressed as a function of: the spacing of binders; the ratio of the bound area to the total area under compression; the size of the binders; and the shape of the concrete cross-section.
Some mechanical aspects of compression testing machines
Authors: Cole D. G.
Published: July 2012

Summary

The paper deals with certain aspects, particularly mechanical, of testing machines which vary considerably from model to model and which can lead to difficulties when strength results obtained from different machines are compared. The results quoted were obtained from examinations carried out on a large number of machines engaged in commercial testing.
Hydration and strength of neat Portland cement
Authors: Chandra D. , Sereda P. J. , Swenson E. G.
Published: July 2012

Summary

In order to examine the relationship between some of the mechanical properties and the degree of hydration of Portland cement, two different methods were used to prepare samples of hydrated cement paste. One method involved hydrating the cement in suspension for different lengths of time in rotating polyethylene bottles (water/cement ratio = 5). The dried powder was then compacted to different porosities. In the other method, the dry unhydrated cement was mixed with plastic beads in the ratio of l:3 by weight and compacted at 10,000 lb/in2 to give a porosity oJ about 38%, and then hydrated by immersion in water. These compacts, which were in the shape of discs of 1·25 in. diameter, were used to measure the modulus of elasticity, fracture strength and indentation hardness. This work indicated that these types of sample can be used to follow the characteristic change in mechanical properties with time and degree of hydration of the cement.
Failure criteria for concrete in compression
Authors: Hannant D. J. , Frederick C. O.
Published: July 2012

Summary

This paper describes the failure surface in three-dimensional stress space of concrete subjected to multiaxial compression with maximum stresses up to eight times the uniaxial compressive strength. It is shown that, if the experimental results presented by several authors are correct, the failure surface for concrete cannot be rotationally axi-symmetric. The suggested shape of failure envelope is approximated to aform which can be represented by simple equations, and a safety factor is defined which enables design equations to be presented.
A modified splitting test for concrete specimens
Authors: Davies J. D.
Published: July 2012

Summary

The paper describes a modified splitting test by means of which it is possible to trace the complete load deformation characteristics of plain concrete loaded beyond the nominal splitting load. It is known that concrete will not exhibit a sudden brittle tensile failure provided the deformation is adequately restrained in some way. In this test, the restraint is provided by a steel beam acting in parallel with the concrete specimen in resisting the load applied by the testing machine. The applied load is carried partly by the concrete and partly by the steel in relation to their respective stiffnesses. As the load increases, the steel carries a higher proportion, and it is possible to extend the test on the concrete into the region where its portion of the applied load decreases as the deformation increases, that is, into the zone of negative stiffness.
Slender reinforced concrete columns with biaxial eccentricity of loading
Authors: Pannell F. N. , Robinson J. L. , Swenson E. G.
Published: July 2012

Summary

Seventeen slender reinforced concrete columns have been tested and the results indicate that the failure load of a slender column under biaxial bending may be predicted in terms of the failure load of an equivalent axially loaded column and the load-moment failure surface of a similar short column under biaxial bending.
Creep of air-entrained concrete
Authors: Ward M. A. , Neville A. M. , Singh S. P.
Published: July 2012

Synopsis

The creep of mixes having the same workability and strength at loading is shown not to be affected by the presence or absence of entrained air, so that the approximate linear relationship between creep and stress/strength ratio previously foundfor plain concrete applies also to air-entrained concrete. A correlation between specific creep and the modulus of elasticity at loading is shown to exist for the full range of concrete, mortar and neat cement paste mixes tested. Air-entrained concrete fits the same curve as that obtained for plain mixes of the same strength because both have the same total void content (air, capillary pores and gel pores). This void content is of fundamental importance in understanding the mechanical properties of concrete.
Strain-hardening effects in reinforced concrete
Authors: Eiklid Gunnar-Erik , Gerstle Kurt H. , Tulin Leonard G.
Published: July 2012

Synopsis

This study is concerned with the effect of strain-hardening upon the response of continuous reinforced concrete beams. An analysis including the effect of strain-hardening of the steel is developed to determine moment-rotation relationships of a beam section, and the results are verified experimentally. These moment-rotation relationships are then used in a piecewiselinear analysis in which the non-linear effects are represented by discrete strain-hardening hinges in order to predict the behaviour of the continuous beams. Analytical and experimental results showed good correlation. The increased load-carrying capacity of under-reinforced beams above that predicted by the simple plastic theory is therefore attributed to the strain-hardening of the steel. A reinforcing parameter called the ‘strain-hardening index’ is introduced to determine the effect of yield range and strain-hardening of the steel upon the strength and rotation capacity of the beam. Lastly, it is shown that the energy absorption capacity is only very slightly affected by the shape of the stress-strain curve of the reinforcing steel.
A curiosity of yield-line analysis
Authors: Taylor R. , Mohamedbhai G. T. G.
Published: July 2012

Synopsis

In the analysis of rectangular reinforced concrete slabs by yield-line theory using the simple diagonal patterns of collapse, it has always been considered a necessary part of the calculation to check that the correct diagonal mode has been used. It is shown that,for most practical cases of slab design, this is not necessary, because the values from the correct and incorrect patterns are almost identical.
Yield-line theory and limit analysis of plates and slabs
Authors: Bræstrup M. W.
Published: July 2012

Synopsis

The usual geometrical, statical and physical conditions for the anisotropic, perfectly plastic plate are given. It is demonstrated that the normal moment criterion usually employed in modern yield-line theory is identical with the ‘stepped’ criterion of the classical theory, and that they both correspond to a yield surface, called the upper yield surface, which satisfies the requirements of limit analysis. When the actual yield surface of the plate is different from the upper yield surface, then the yield load predicted by limit analysis can generally not be determined by yield-line theory. It is not even possible to approach the solution by successive refinement of the yield-line pattern. The common yield surfaces of metal plates are compared with the upper yield surface, and the yield surface of the arbitrarily reinforced concrete slab is derived. Finally, the relationship between yield-line theory and limit analysis is discussed, and it is concluded that the two theories are consistent in their foundation.
Regain of strength after firing of concrete
Authors: Crook D. N. , Murray M. J.
Published: July 2012

Synopsis

The mechanism of regain of strength as observed in work on the glazing of concrete was investigated on fired and unfired industrially made masonry units by methods including DTA, pore size distribution, and determination of the degree of carbonation. Immediate loss of strength after firing is attributed to the dehydration of cement paste gel, and the main factor in the regain of mechanical strength in a fired block is a carbonation process facilitated by a new capillary system created in firing.