bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical and laboratory characteristics of infectious mononucleosis by Epstein-Barr virus in Mexican children
Authors: González Saldaña Napoleón , Monroy Colín Victor Antonio , Piña Ruiz Georgina , Juárez Olguín Hugo
Published: July 2012

Background

Infectious mononucleosis (IM) or Mononucleosis syndrome is caused by an acute infection of Epstein-Barr virus. In Latin American countries, there are little information pertaining to the clinical manifestations and complications of this disease. For this reason, the purpose of this work was to describe the clinical and laboratory characteristics of infection by Epstein-Barr virus in Mexican children with infectious mononucleosis.

Methods

A descriptive study was carried out by reviewing the clinical files of patients less than 18 years old with clinical and serological diagnosis of IM by Epstein-Barr virus from November, 1970 to July, 2011 in a third level pediatric hospital in Mexico City.

Results

One hundred and sixty three cases of IM were found. The most frequent clinical signs were lymphadenopathy (89.5%), fever (79.7%), general body pain (69.3%), pharyngitis (55.2%), hepatomegaly (47.2%). The laboratory findings were lymphocytosis (41.7%), atypic lymphocytes (24.5%), and increased transaminases (30.9%), there were no rupture of the spleen and no deaths among the 163 cases.

Conclusions

Our results revealed that IM appeared in earlier ages compared with that reported in industrialized countries, where adolescents are the most affected group. Also, the order and frequency of the clinical manifestations were different in our country than in industrialized ones.
5-Fluorouracil induces apoptosis in rat cardiocytes through intracellular oxidative stress
Authors: Lamberti Monica , Porto Stefania , Marra Monica , Zappavigna Silvia , Grimaldi Anna , Feola Daniela , Pesce Delia , Naviglio Silvio , Spina Annamaria , Sannolo Nicola , Caraglia Michele
Published: July 2012

Background

Cardiotoxicity is a major complication of anticancer drugs, including anthracyclines and 5-fluorouracil(5-FU) and it can have detrimental effects both in patients and workers involved in the preparation of chemotherapy.

Methods

Specifically, we have assessed the effects of increasing concentrations of 5-FU and doxorubicin (DOXO) on proliferation of H9c2 rat cardiocytes and HT-29 human colon adenocarcinoma cells by MTT assay. Cells were treated for 24, 48 and 72 h with different concentrations of the two drugs alone or with 5-FU in combination with 10-4 M of levofolene (LF).

Results

5-FU induced a time- and dose-dependent growth inhibition in both cell lines. The 50% growth inhibition (IC:50) was reached at 72 h with concentrations of 4 μM and 400 μM on HT-29 and H9c2, respectively. The addition of LF to 5-FU enhanced this effect. On the other hand, the IC:50 of DOXO was reached at 72 h with concentrations of 0.118 μM on H9c2 and of 0.31 μM for HT-29. We have evaluated the cell death mechanism induced by 50% growth inhibitory concentrations of 5-FU or DOXO in cardiocytes and colon cancer cells. We have found that the treatment with 400 μM 5-FU induced apoptosis in 32% of H9c2 cells. This effect was increased by the addition of LF to 5-FU (38% of apoptotic cells). Apoptosis occurred in only about 10% of HT-29 cells treated with either 5-FU or 5-FU and LF in combination. DOXO induced poor effects on apoptosis of both H9c2 and HT-29 cells (5–7% apoptotic cells, respectively). The apoptosis induced by 5-FU and LF in cardiocytes was paralleled by the activation of caspases 3, 9 and 7 and by the intracellular increase of O2− levels.

Conclusions

These results suggest that cardiotoxic mechanism of chemotherapy agents are different and this disclose a new scenario for prevention of this complication.
Intramedullary screw fixation with bone autografting to treat proximal fifth metatarsal metaphyseal-diaphyseal fracture in athletes: a case series
Authors: Tsukada Sachiyuki , Ikeda Hiroo , Seki Yoshie , Shimaya Masayuki , Hoshino Akiho , Niga Sadao
Published: July 2012

Background

Delayed unions or refractures are not rare following surgical treatment for proximal fifth metatarsal metaphyseal-diaphyseal fractures. Intramedullary screw fixation with bone autografting has the potential to resolve the issue. The purpose of this study was to evaluate the result of the procedure.

Methods

The authors retrospectively reviewed 15 athletes who underwent surgical treatment for proximal fifth metatarsal metaphyseal-diaphyseal fracture. Surgery involved intramedullary cannulated cancellous screw fixation after curettage of the fracture site, followed by bone autografting. Postoperatively, patients remain non weight-bearing in a splint or cast for two weeks and without immobilization for an additional two weeks. Full weight-bearing was allowed six weeks postoperatively. Running was permitted after radiographic bone union, and return-to-play was approved after gradually increasing the intensity.

Results

All patients returned to their previous level of athletic competition. Mean times to bone union, initiation of running, and return-to-play were 8.4, 8.8, and 12.1 weeks, respectively. Although no delayed unions or refractures was observed, distal diaphyseal stress fractures at the distal tip of the screw occurred in two patients and a thermal necrosis of skin occurred in one patient.

Conclusions

There were no delayed unions or refractures among patients after carrying out a procedure in which bone grafts were routinely performed, combined with adequate periods of immobilization and non weight-bearing. These findings suggest that this procedure may be useful option for athletes to assuring return to competition level.
Cross-species genomic and functional analyses identify a combination therapy using a CHK1 inhibitor and a ribonucleotide reductase inhibitor to treat triple-negative breast cancer
Authors: Bennett Christina N , Tomlinson Christine C , Michalowski Aleksandra M , Chu Isabel M , Luger Dror , Mittereder Lara R , Aprelikova Olga , Shou James , Piwinica-Worms Helen , Caplen Natasha J , Hollingshead Melinda G , Green Jeffrey E
Published: July 2012

Introduction

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is diagnosed in approximately 15% of all human breast cancer (BrCa) patients. Currently, no targeted therapies exist for this subtype of BrCa and prognosis remains poor. Our laboratory has previously identified a proliferation/DNA repair/cell cycle gene signature (Tag signature) that is characteristic of human TNBC. We hypothesize that targeting the dysregulated biological networks in the Tag gene signature will lead to the identification of improved combination therapies for TNBC.

Methods

Cross-species genomic analysis was used to identify human breast cancer cell lines that express the Tag signature. Knock-down of the up-regulated genes in the Tag signature by siRNA identified several genes that are critical for TNBC cell growth. Small molecule inhibitors to two of these genes were analyzed, alone and in combination, for their effects on cell proliferation, cell cycle, and apoptosis in vitro and tumor growth in vivo. Synergy between the two drugs was analyzed by the Chou-Talalay method.

Results

A custom siRNA screen was used to identify targets within the Tag signature that are critical for growth of TNBC cells. Ribonucleotide reductase 1 and 2 (RRM1 and 2) and checkpoint kinase 1 (CHK1) were found to be critical targets for TNBC cell survival. Combination therapy, to simultaneously attenuate cell cycle checkpoint control through inhibition of CHK1 while inducing DNA damage with gemcitabine, improved therapeutic efficacy in vitro and in xenograft models of TNBC.

Conclusions

This combination therapy may have translational value for patients with TNBC and improve therapeutic response for this aggressive form of breast cancer.
Association of hemoglobin concentration and mortality in critically ill patients with severe traumatic brain injury
Authors: Sekhon Mypinder S , McLean Nielson , Henderson William R , Chittock Dean R , Griesdale Donald EG
Published: July 2012

Introduction

The critical care management of traumatic brain injury focuses on preventing secondary ischemic injury. Cerebral oxygen delivery is dependent upon the cerebral perfusion pressure and the oxygen content of blood, which is principally determined by hemoglobin. Despite its importance to the cerebral oxygen delivery, the precise hemoglobin concentration to provide adequate oxygen delivery to injured neuronal tissue in TBI patients is controversial with limited evidence to provide transfusion thresholds.

Methods

We conducted a retrospective cohort study of severe TBI patients, investigating the association between mean 7-day hemoglobin concentration and hospital mortality. Demographic, physiologic, intensive care interventions, clinical outcomes and daily hemoglobin concentrations were recorded for all patients. Patients were all cared for at a tertiary, level 1 trauma center in a mixed medical and surgical intensive unit. Patients were divided into quartiles based on their mean 7-day hemoglobin concentration: < 90 g/L, 90 - 99 g/L, 100 - 109 g/L and > 110 g/L. Multivariable log-binomial regression was used to model the association between mean daily hemoglobin concentration and hospital mortality.

Results

Two hundred seventy-three patients with traumatic brain injury were identified and 169 were included in the analysis based on inclusion/exclusion criteria. Of these, 77% of the patients were male, with a mean age of 38 (SD 17) years and a median best GCS of 6 (IQR 5 - 7). One hundred fifteen patients (68%) received a red blood cell (RBC) transfusion. In RBCs administered in the ICU, the median pre-transfusion hemoglobin was 79 g/L (IQR 73 - 85). Thirty-seven patients (22%) died in hospital. Multivariable analysis revealed that mean 7-day hemoglobin concentration < 90 g/L was independently associated with an increased risk of hospital mortality (RR 3.1, 95% CI 1.5 - 6.3, p = 0.03). Other variables associated with increased mortality on multivariable regression were insertion of external ventricular drain, age and decreased GCS. Red blood cell transfusion was not associated with mortality following multivariable adjustment.

Conclusions

A mean 7-day hemoglobin concentration of < 90g/L is associated with increased hospital mortality in patients with severe traumatic brain injury.
Population-Based Longitudinal Study of Follow-Up Care for Patients With Colorectal Cancer in Nova Scotia
Authors: Urquhart Robin , Folkes Amy , Porter Geoffrey , Kendell Cynthia , Cox Martha , Dewar Ron , Grunfeld Eva
Published: July 2012

Transitioning routine follow-up to primary care could potentially increase guideline adherence by improving access to and continuity of care.
Task dependent activity of motor unit populations in feline ankle extensor muscles
Authors: Hodson-Tole Emma F. , Pantall Annette L. , Maas Huub , Farrell Brad J. , Gregor Robert J. , Prilutsky Boris I.
Published: July 2012

Understanding the functional significance of morphological diversity of mammalian skeletal muscles is limited by technical difficulties of estimating the contribution of motor units with different properties to unconstrained motor behaviours. Recently developed wavelet and principal components analysis of intramuscular myoelectric signals has linked signals with lower and higher frequency contents to use of slower and faster motor unit populations. In this study we estimated the relative contributions of lower- and higher-frequency signals of cat ankle extensors (soleus, medial and lateral gastrocnemii; plantaris) during level, downslope and upslope walking and the paw-shake response. This was done using the first two myoelectric-signal principal components (PCI, PCII), explaining over 90% of signal, and an angle theta, a function of PCI/PCII, indicating the relative contribution of slower and faster motor unit populations. Mean myoelectric frequencies in all walking conditions were lowest for slow soleus (234 Hz) and highest for fast gastrocnemii (307 and 330 Hz) muscles. Motor unit populations within and across the studied muscles that demonstrated lower myoelectric frequency (suggesting slower populations) were recruited during tasks and movement phases with lower mechanical demands on the ankle extensors - during downslope and level walking and in early walking stance and paw-shake phases. With increasing mechanical demands (upslope walking, mid-phase of paw-shake cycles), motor unit populations generating higher frequency signals (suggesting faster populations) contributed progressively more. We concluded that the myoelectric frequency contents within and between feline ankle extensors vary across studied motor behaviours with the patterns that are generally consistent with muscle fibre type composition.
Fabrication of Nanoengineered Metallic Structures and Their Application to Nonlinear Photochemical Reactions
Authors: Ueno Kosei , Misawa Hiroaki
Published: July 2012

We used metallic nanoparticles exhibiting localized surface plasmon resonance and electromagnetic (EM) field enhancement effects induced by plasmon excitation for the photochemical reaction field; this approach makes it possible to increase the probability of an interaction between photons and the materials. EM field enhancement effects induced by gold nanostructures were elucidated using two-photon-induced photoluminescence from nanogap-spaced gold nanoparticles. The photoluminescence was promoted mainly in the surface regions of the gold nanoblocks adjacent to the nanogaps due to the EM field enhancement effect. To elucidate the near-field intensity distribution of the nanogap gold structures, we investigated the photopolymerization of a commercially available negative photoresist assisted by EM field enhancement in the nanogaps separating the gold nanoblocks. Photopolymerization rates were enhanced by several orders of magnitude in the gold nanoblock structures that contained nanogaps narrower than 10 nm. We propose two surface plasmon-assisted nanolithography techniques based on spatially selective photochemical reactions promoted by the EM field enhancement effect. The first method uses ultimate near-field lithography with a local near-field distribution induced in the nanogaps, and the second technique uses the scattering component of multipole plasmon resonance as an exposure mechanism. These lithographic techniques represent a type of application based on plasmon-enhanced chemical reactions.
Predicting portal hypertension as assessed by acoustic radiation force impulse: correlations with the Doppler ultrasound
Authors: Han J-Y , Cho J H , Kwon H J , Nam K J
Published: July 2012

Objective The purpose of this study was to assess the value of acoustic radiation force impulse (ARFI) for evaluating portal hypertension by correlating the elasticity of liver cirrhosis, as measured by ARFI, with haemodynamic indices measured by Doppler ultrasound.

Methods We evaluated the data of a total of 154 prospectively enrolled patients who underwent both duplex Doppler ultrasound and ARFI imaging. The duplex Doppler ultrasound indices, including the mean portal vein velocity, splenic index (SI) and splenoportal index (SPI) were evaluated to determine the statistical correlation with shear wave velocity (SWV) of ARFI. We also analysed the differences in the correlations between the SI, SPI and SWV of the group who had varices. The correlations were assessed with Spearman′s rank correlation coefficients.

Results There was an increase of SWV in parallel with the increase of the SI (ρ=0.409, p<0.01) and SPI (ρ=0.451, p<0.01). In the patient group who did not have varices (n=74), the Doppler indices were found to be more correlated with the SWV (SI: ρ=0.447, SPI: ρ=0.552, p<0.01). However, the group with varices showed no correlation between the SWV and the Doppler parameters.

Conclusion SWV of ARFI was well correlated statistically with Doppler parameters, but is of limited value in predicting portal hypertension directly owing to great variability of Doppler parameters. By evaluating the correlation between ARFI and Doppler ultrasound, we suggest that the SWV might be a non-invasive supplementary tool for predicting portal hypertension.
Wireless Impedance Sensor Node and Interface Washer for Damage Monitoring in Structural Connections
Authors: Kim Jeong-Tae , Nguyen Khac-Duy , Park Jae-Hyung
Published: July 2012

In this study, a technique using wireless impedance sensor node and interface washer is proposed for monitoring damage in structural connections of bridges. In order to achieve the objective, the following approaches are implemented. First, a wireless impedance sensor node is designed for automated and cost-efficient monitoring in structural connections. Second, impedance-based algorithms are embedded in the wireless impedance sensor node for autonomous monitoring of structural connections. Third, a tensile-force monitoring technique using an interface washer is proposed to overcome limitations of the wireless impedance sensor node such as measureable ranges with narrow frequency band, and the proposed technique is numerically validated. Finally, the performance of the wireless impedance sensor node and the interface washer is experimentally evaluated in cable-anchor connection and bolted connection models.
Application of Structural Health Monitoring System for Reliable Seismic Performance Evaluation of Infrastructures
Authors: Yi Jin-Hak , Kim Dookie , Go Sunghyuk , Kim Jeong-Tae , Park Jae-Hyung , Feng Maria Q. , Kang Keum-Seok
Published: July 2012

In this study, the useful application of an instrumented structural health monitoring (SHM) system is proposed for the reliable seismic performance evaluation based on measured response data. A seismic fragility is chosen as a key index for probabilistic seismic performance assessment on an infrastructure. The seismic performance evaluation procedure consists of the following five main steps; (1) measuring ambient vibration of a bridge under general traveling vehicles; (2) identifying modal parameters including natural frequencies and mode shapes from the measured acceleration data by output-only modal identification method; (3) updating linear structural parameters in a preliminary finite element (FE) model using the identified modal parameters; (4) analyzing nonlinear response time histories of the structure using nonlinear seismic analysis program; and finally (5) evaluating the probabilistic seismic performance in terms of seismic fragility. In the present study, the seismic fragility curves are represented by a log-normal distribution function. An instrumented highway bridge is utilized to demonstrate the proposed evaluation procedure and it is found that the seismic fragility of a highway bridge can be reliably evaluated by combining the modal information obtained from the instrumented SHM system and FE model updating by using the information.
A Multiple Random Decrement Method for Modal Parameter Identification of Stay Cables Based on Ambient Vibration Signals
Authors: Wu Wen-Hwa , Chen Chien-Chou , Liau Jau-An
Published: July 2012

The cables of cable-stayed bridges are the primary force-transmitting members of the whole structure and consequently play an important role in reflecting the dynamic characteristics and health condition of the total bridge system. The dynamic response of the cable generally attributes to numerous lower modes because of its low flexural stiffness. Accordingly, the parameters of more modes are usually required for stay cables than other civil structures. It is aimed in this study to develop an effective method for accurately identifying the parameters of various cable modes merely based on the ambient vibration measurement of a single sensor installed on each cable. A mode separation technique is first introduced to extract the independent contributions to the measured signal of cable from individual modes. A multiple random decrement method is further developed to completely exclude the excitation effect and extract the free vibration response. With the combination of the above two techniques, convenient identification techniques such as the Ibrahim time domain method can then be applied to independently identify the individual parameters for each mode. The whole methodology is demonstrated by applying it to the ambient velocity measurements for the cables of Chi-Lu Bridge. Imitating the identified parameter values from the actual measurements, SAP200 models for three different types of cable are constructed to simulate the ambient vibration signals. These simulated signals are finally used for identification to verify the effectiveness and accuracy of this method.
Self-assembled nanometric spacer on surface of natural rubber composited with TiO2
Authors: Taweepreda W. , Phatcharasit K.
Published: July 2012

The dispersion of titanium dioxide (TiO2) was mixed with natural rubber latex (NRL) and other additives before casting on glass slide. The dispersion of TiO2 (75% by wt.) were prepared using high pressure homogenizer by varying the concentration of stabilizer, poly (ethylene glycol) (PEG). The results were found that PEG can disperse TiO2 in water phase and the mechanical properties of NRL film composited with TiO2 dispersion is enhancement with increasing the PEG concentration. The effects of the stabilizer and NRL compounding on composited films properties were discussed using surface morphology. The morphology of TiO2 dispersion and composited NRL films were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM).
Modeling of unixial and biaxial ratcheting of austenitic steel using Chaboche model
Authors: Meziani Salim , Djimli Lynda , Taleb Lakhdar
Published: July 2012

This paper is devoted to the study of the role of identification data base on the prediction of the cyclic behavior of the 304 L stainless steel on ambient temperature. The identification is done using the Chaboche constitutive model. The investigations have been performed with reference to both unixial and biaxial experimental data, strain controlled tests, ratchet tests, ratchet tests after a strain controlled strain tests. Results were reported in graphs representing the effect of the optimized parameters on the prediction of the behavior of the material. The parameters of the Chaboche model have been calculated from the curve of a unixial strain controlled test. Then they were optimized using different data base on ZéBuLoN. The simulation obtained by optimized parameters gives a good representation of stabilised loop in the way it is done with the simulated test. Ratchet was also well predicted in the case of optimization done with all tests considered in the simulation. In this paper it has been demonstrated that the optimization using different data bases have a big impact on the cyclic results and ratchet results.
Documentation of Weathered Architectural Heritage with Visible, near Infrared, Thermal and Laser Scanning Data
Authors: Lerma J. L. , Cabrelles M. , Akasheh T. S. , Haddad N.A.
Published: July 2012

Documentation of cultural heritage requires simple, quick and easy to use multi-sensor approaches to determine the state of conservation of monuments and sites. The documentation of a highly weathered architectural heritage such as the Obelisk Tomb is a good example to test the performance integrating multispectral imagery and laser scanning data. The Obelisk Tomb is the first important façade that a visitor sees while entering to the archaeological site of Petra in Jordan. The rich architectural formations carry Egyptian, Hellenistic and Nabataean influences. The damage that was inflicted on this unique monument led us to study it applying a number of modern digital techniques including 3D scanning, multispectral photography with visible and near infrared images, and thermography. All the multiband content is initially registered onto different multispectral bands. The multispectral information is enhanced and eventually draped onto the 3D laser scanning model in order to improve documentation and analysis of the state of conservation. Our results integrating the multispectral data, thermography and terrestrial laser scanning clearly enhance the power of diagnosis over the Obelisk Tomb with state-of-the-art optical equipment and image processing software. Furthermore, the capacity to examine, analyse and detect the existing damages is enhanced by the false colour processing of the input photographic data. Weathering effects are highlighted onto the 3D model and shed some light on the causes of the damages.
Preliminary Risk Assessment at the Petra Archaeological Park Recording Strategy
Authors: Cesaro G. , Quintero M. Santana , Paolini A. , De Vos P. J. , Glekas E. , Visconti L.
Published: July 2012

This paper describes the activities carried out in Petra by an international and multidisciplinary group of graduate students specializing in heritage conservation from the Raymond Lemaire International Centre for Conservation (RLICC), University of Leuven (Belgium) in cooperation with the University of Jordan, Faculty of Architecture, the Al Hussein Bin Talal University and in partnership with the UNESCO Office in Amman. The main objective of the work was to carry out a preliminary assessment of the risks affecting the integrity of the Petra World Heritage Property, due to both natural and man-made events so to understand the impact of the site's major threats. The outcomes provided the foundations necessary to develop a risk management plan, which should be integrated in the development of a comprehensive management plan for the site. The result of the overall study has been a preliminary risk management recommendation achieved through a rapid risk assessment of specific areas within the property, which readily identified vulnerabilities and threats to the state of conservation of the PAP. Outcomes of this work comprise two movies using time-lapse photography, 25 geo-referenced panoramas, a GIS system showing GPS track logs for all trails, satellite imagery and location of facilities, signage, monuments, 395 geo-referenced photos for the trails assessment, 105 geo-referenced photos for the areas assessment. An easy way to understand and visualize the circulation in the PAP was to bring the different trails on a satellite image through the use of a GPS system, combined with the ArcGIS software, in order to create a live track log while walking the trails in the PAP. Tracing this track log later in the GIS software indicated the actual location of parts of the PAP circulation and proved a very useful tool to retrieve the paths and areas analyzed.
Men Too Sometimes Shy Away from Competition: The Case of Team Competition
Authors: Dargnies Marie-Pierre
Published: July 2012

Recent results in experimental and personnel economics indicate that women do not like competitive environments as much as men. This paper presents an experimental design that gives participants the opportunity to enter a tournament as part of a team rather than alone. Although a large and significant gender gap in entry in the individual tournament is found, in line with the literature, no gender gap is found in entry in the team tournament. Women do not enter the tournament significantly more often when it is team based, but men enter significantly less when they are part of a team than when alone. The main reason for men's disaffection with team competition appears to be linked to the uncertainty of their teammate's performance in a team tournament. More precisely, high-performing men fear being the victims of the free-riding behavior of their teammate. Women, especially low-performing women, tend to enter the team tournament more often than the individual one when they know they will be matched to a teammate of the same level as their own.

This paper was accepted by Teck Ho, decision analysis.
Momentum and Organizational Risk Taking: Evidence from the National Football League
Authors: Lehman David W. , Hahn Jungpil
Published: July 2012

This study examines how momentum shapes organizational risk taking. We define momentum as a sustained and systematic trajectory in performance over time, and we argue that such trends impact interpretations of current performance as well as expectations of future performance. Drawing on the variable focus of attention model, we posit that momentum therefore directs the focus of organizational attention between concerns of aspirations, survival, and slack. Our conceptual model accounts for momentum that occurs within a performance period as well as that which occurs across periods. We propose that within- and across-period momentums are unique in terms of when and how each type impacts risk taking. We tested and found support for our hypotheses in the context of 22,603 play-by-play decisions made by the 32 teams of the National Football League during the 2000–2005 regular season games. Theoretical and practical implications are discussed.

This paper was accepted by Jesper Sørensen, organizations.
Reduction of Emission in a Diesel Engine Using Nanofuel – Ceria Nanoparticle Dispersed Diesel
Authors: Mandal Saptarshi , Kanagaraj S.
Published: July 2012

About one-third of passenger vehicles available in the world market are diesel powered, which leads to greater emphasis on improving the performance of a diesel engine without changing the engine configuration. In this study, an attempt has been made to improve the combustion efficiency of nanofuel, CeO2 nanoparticles dispersed diesel. It was prepared using a tip sonicator with different concentration of ceria varied in the range of 0.02, 0.04, 0.06, 0.08, and 0.10 wt. % in diesel. Cerium concentration in diesel played an important role to control the concentration of toxic exhaust gases by influencing the complete combustion of fuel. The maximum reduction of emission gases and an increase of engine performance were observed at an optimum condition of 75 % of load and 0.06 wt. % of CeO2 in diesel, where brake thermal and mechanical efficiency were increased by 10 % and 7 %, respectively and the specific fuel consumption, NOx, and CO was found to be decreased by 10 %, 50 %, and 40 %, respectively. It is concluded that the use of nanofuel is a very efficient tool to protect our environment from the toxic gases emitted from the burning of fossil fuel.
„Das Amt“ zwischen Versailles und Rapallo
Authors: Neitzert Dieter
Published: July 2012

Vorspann

Ernst von Simsons neu entdecktes Erinnerungsfragment ist keine Sensation, aber doch in dreierlei Hinsicht eine Rarität, die besondere Beachtung verdient: Hier schreibt ein hoher Beamter, der im Staatsdienst vor und nach 1918 viel erlebt hat. Hier berichtet ein kenntnisreicher Außenpolitiker, der in Versailles und Rapallo dabei war, als Weichen gestellt wurden, und hier blickt ein Mann zurück, der vom NS-Regime zum Juden gestempelt und ins Exil gedrängt wurde – trotz seiner immensen Verdienst um sein Volk, die er seinen ehrwürdigen Kollegen im „Amt“ nicht mehr vor Augen führen konnte. In den Geschichtsbüchern werden sie aber ihren Platz finden.
União de juntas dissimilares alumínio-aço de chapas finas pelo processo de soldagem por atrito com pino não consumível (SAPNC)
Authors: Torres Edwar Andrés , Ramirez Antonio Jose
Published: July 2012

Foram obtidas juntas dissimilares da liga de alumínio 6063-T5 e do aço AISI SAE 1020 com espessura de 2,0 mm soldadas por atrito com pino não consumível. O objetivo deste trabalho é avaliar o efeito da penetração e o deslocamento da ferramenta na obtenção de juntas soldadas Al-aço. As juntas foram avaliadas segundo a qualidade da superfície e a profundidade da região soldada. Foi determinado que além das velocidades de rotação (ω) e avanço (ν), o deslocamento e a profundidade de penetração da ferramenta são parâmetros fundamentais, pois definem o aporte térmico e, com este, a aderência ou não de alumínio na ferramenta, a qualidade superficial e a formação de defeitos ao longo da linha da junta.
Essential body of legal knowledge
Authors: Soo Gary , Lam Solomon
Published: July 2012

With the escalating economic growth in construction activities around the world, construction disputes are on the rise again. The construction industry worldwide is on the lookout for better ways to resolve various types of construction disputes. To this end, the roles and functions of forensic engineers in assisting the appropriate resolution of such disputes are much more demanding than before. Knowledge about the legal process and expectations upon forensic engineers are equally crucial as technical knowledge in this regard. Many forensic engineers learn these by training, but some through unfortunate experiences and at the expense of their clients. To ensure the proper discharge of their duties to the parties and to the tribunals, there is a body of legal knowledge with which forensic engineers need to be equipped. Through exploring and studying cases and practices in the UK, Hong Kong and Australia, this paper reviews the essential legal knowledge and hence the protocol of conduct expected from forensic engineers in these countries. In addition, an attempt is made to highlight those issues to be considered by educators of forensic engineers in this regard. The ultimate aim is to provide a checklist of content for the body of knowledge to improve the overall education of forensic engineers in this field.
Elastoplastic consolidation beneath shallowly embedded offshore pipelines
Authors: Chatterjee S. , Yan Y. , Randolph M. F. , White D. J.
Published: July 2012

The consolidation response of partially embedded seabed pipelines has been investigated in the past using small-strain finite-element (SSFE) analysis with elastic soil response. This paper presents results from large-deformation finite-element (LDFE) analyses, using the modified Cam Clay plasticity model for the soil, to address the problem more realistically, including initial plastic penetration of the pipe. The effects of initial embedment, pipe–soil interface friction and strength gradient have been explored in a systematic manner and comparisons with the elastic solutions show the influence of non-linearity. Effects of local soil heave on consolidation rate are quantified by comparing results from SSFE and LDFE analyses. The dissipation responses are fitted by simple equations to aid application in design.
Prestressed concrete: outline of design for bending stresses
Authors: Devis C. E.
Published: July 2012

Summary:

This paper gives the practical engineer a brief and somewhat unusual approach to the theory of prestressed concrete design, and thence develops the formulae essential to design.

Analysis of the stresses in a designed section then follows, and the important moment-stress diagram is illustrated. The latter will be of particular interest to field engineers.
Tests of prestressed concrete beams with alloy steel bars
Authors: Ross A. D.
Published: July 2012

Summary

The paper reports a series of tests of beams prestressed on a system, developed by Mr. Donovan Lee, which utilizes alloy steel bars with an ultimate tensile strength of about 70 tons per sq. in. in diameters up to 1 ⅛ in. The beams were constructed and tested at the Field Test Unit of the Ministry of Works, which has since become the Building Operations Research Unit of the D.S.I.R. Details are given of the five test beams of I- and U-shaped cross sections. Some Were assembled from precast elements and others were monolithic. The spans varied from 21 ft 6 in. to 46 ft 6 in. and the total prestressing force from 27·5 to 89·1 tons.

The method of loading, the sequence of the tests and the recording of deflexions and strains are described. Typical strain and deflexion curves are given, and the results are presented in tables showing loads at cracking and failure, deflexions at working loads and ultimate load factors.

Measurements on the steel were obtained in one of the beams, and data on the strain during prestressing, anchoring and loading are also given.
The relationship between compressive strength and age for soils stabilized with four types of cement
Authors: Clare K. E. , Pollard A. E.
Published: July 2012

Summary:

The relationships between unconfined compressive strength and age up to 28 days have been determined for soil-cement specimens made with a sand, a silty clay and a clay, stabilized with four different cements. A comparison has also been made of the effects on compressive strength of coating test specimens with wax and of placing them in a humid atmosphere during the curing period.

High-alumina cement was found to give the highest strength after 24 hours, wirh all three soils, but afier 28 days it gave lower strengths than the other cements. Rapid-hardening cement was found to give strengths 20-40 lb per sq. in. greater than normal Portland cement with the two cohesive soils, while super-rapid-hardening cement generally gave strengths about 40 lb per sq. in. lower than those obtained with the other two Portland-type cements.

The setting of normal Portland and rapid-hardening cement mixed with the sand was retarded for seven days, due to an organic impurity, but the setting of high-alumina cement was not affected. The addition of lime, or calcium chloride (e.g. in super-rapid-hardening cement) was found to reduce the retardation, the latter being the most effective. The action of calcium chloride in this respect was confirmed with three other soils containing deleterious organic matter.

Coating test specimens with paraffin wax during the curing period was found to result in considerably smaller differences in moisture content among similar specimens in a batch than was obtained by storage in a humid atmosphere. This was accompanied by a reduction in the differences in the unconfined compressive strength of specimens only in the case of the sand-cement.

The average limits of error of the mean compressive strengths based on ten independent measurements were calculated to be between ±10 and ±20 lb per sq. in. for strengths ranging between 200 and 400 lb per sq. in.
The bearing capacity of concrete and rock
Authors: Meyerhof G. G.
Published: July 2012

Summary

The results of published work relating to triaxial compression tests on concrete and rock are briefly analysed to determine the principal strength characteristics which govern the bearing capacity of blocks subjected to concentrated loads and offoundations of concrete and rock. A simple method of estimating the bearing capacity of footings on blocks of various sizes is suggested, and is checked by the results of previous model tests. To obtain further information, especially for large blocks, a series of loading tests has been made on mass and reinforced concrete blocks. The observed bearing capacity, mechanism and extent offailure are analysed and found to be in fair agreement with the theoretical estimates.
The strength of plain, reinforced and prestressed concrete under the action of combined stresses, with particular reference to the combined bending and torsion of rectangular sections
Authors: Cowan Henry J.
Published: July 2012

Summary

A theory for the strength of concrete and reinforced concrete under the action of combined stresses is advanced, which combines Rankine's maximum principal stress criterion and Coulomb's internal friction criterion. Equations for the strength of plain, reinforced and prestressed concrete in combined bending and torsion are then derived. The distinct difference between primary bending and primary torsion fracture is explained by the dual character of the criterion of failure. It also accounts for the increase in the torsional strength of a reinforced concrete section resulting from the addition of bending. Prestressing delays the formation of tension cracks until the compression due to the initial prestress has been offset, and it therefore effects a very great improvement in the torsional strength of concrete.
The thermal diffusivity of hardened cement paste
Authors: Hoyle Russell
Published: July 2012

Summary

The thermal diffusivity of hardened cement paste was measured by immersing long square bars in a steam atmosphere. Thermocouples were used to read temperature at the surface and on the axial centre line during the period of unsteady state of temperature distribution. By reference to existing information for an infinitely long square bar the thermal diffusivity of cement was calculated for each specimen.
A preliminary investigation of the use of fibre-glass for prestressed concrete
Authors: Rubinsky Ivan A. , Rubinsky Andrew
Published: July 2012

Summary

This paper discusses the feasibility of using fibre-glass reinforcement for prestressed concrete, summarizing the physical properties of fibre-glass and some experimental work carried on by the authors. It also gives practical suggestions for future research and concludes with a comparison between fibre-glass and conventional steel reinforcement
A note on the transverse moments in a prestressed concrete bridge slab
Authors: Rowe R. E.
Published: July 2012

Summary

The distribution of load in bridge deck systems(1)* is arousing considerable interest at the present time and this note deals with the application of the theories of Massonnet(2) and Guyon(3) to a flat slab bridge model. Particular mention is made of the distribution and the absolute values of the transverse moments in relation to the theoretical values. Only one slab has been tested at the time of writing but further tests on slabs of different span/breadth ratios are now in progress
Comments on an indirect tensile test on concrete cylinders
Authors: Wright P. J. F.
Published: July 2012

Summary

A test which originated in Brazil for determining the tensile strength of concrete involves applying a compressive load to opposite generators of a cylindrical specimen. The specimenfaiL~ in tension along the diametral plane containing the load. Experiments with this teot have shown that:

(1) Packing strips of relatively soft material are necessary between the specimen and the platens of the testing machine. Plywood strips ½ in. wide and ⅛ in. thick are satisfactory for the purpose, but the material and dimensions of the strips have little effect, provided they can conform to small irregularities in the surface of the specimen.

(2) Cylinders 6 in. in diameter by 6 in. long may be usedfor concrete containing aggregate up to ¾ in. maximum size. Longer specimens may tend to give more uniform results, while smaller specimens may give higher average values.

(3) The new test gives results higher than those given by a direct tensile test, but lower than the modulus of rupture of beams. It tends to give more uniform results than the direct tension or transverse test, but less uniform results than a compression test on cubes.
An alinement chart for the evaluation of the dynamic modulus of elasticity and Poisson's ratio for concrete
Authors: King W. H. , Lee I. D. G.
Published: July 2012

Summary

The report describes the method of construction and use of an alinement chart for the solution of the dynamic modulus of elasticity and Poisson's ratio from observations obtained in the electrodynamic test for longitudinal resonant frequency and the test for ultrasonic pulse velocity of concrete specimens.
The influence of size of concrete test cubes on me all strength and standard deviation
Authors: Neville A. M.
Published: July 2012

Summary

It is suggested that the mean strength and the standard deviation of a sample of concrete cubes are functions of the cube size. The results of tests on over 300 cubes of three sizes are given, and from the statistical analysis of these results it is concluded that the smaller 2·78 in. cubes have a significantly higher mean strength and higher standard deviation than the larger 5 in. and 6 in. cubes.

From these results, it is suggested that the standard deviation obtained from standard 2·78 in. mortar cubes gives an excessive estimate of the effect of the variation in cement quality as compared with the results obtained from 6 in. or 4 ill. concrete cubes.
The use of cements of different fineness in soil-cement mixtures
Authors: Clare K. E. , Farrar D. M.
Published: July 2012

Summary

A study of the literature has shown that increasing the fineness of the cement in mortar and concrete mixes results in an increase in their strength at early ages. This paper describes tests to determine whether a similar effect is obtained with mixtures of soil and cement, so that if possible a reduction could be made in the proportion of cement used in soil stabilization by using a cement of greater fineness than the commercial varieties now employed.

That fraction of a sample of ordinary Portland cement that passed the B.S. No. 300 sieve was added to a silty clay and test specimens were prepared. The 7-day unconfined compressive strength obtained was found to be 140% of the strength obtained when the whole cement was used. Taking the compressive strength at 7 days as the criterion, this suggests that if 10% of ordinary Portland cement was normally required to stabilize this soil, 7% of the fine-grained cement should prove equally satisfactory.

In further tests, a cement clinker was ground to three different degrees of fineness in a laboratory ball mill, the coarsest being equivalent to ordinary Portland cement. The 7-day compressive strength obtained when the finest cement (specific surface = 5,800 cm2/g) was added to the silty clay was 125% of the strength obtained when the coarsest cement (specific surface = 2,900 cm2/g) was used. The corresponding increase for mixtures of sand and cement was 120%.

Chemical analysis showed that the removal of the coarse grains in an ordinary Portland cement increased the proportion of sulphur trioxide present. In a third series of experiments, the compressive strength of a cement-stabilized silty clay obtained with a cement of given fineness was found to increase when the proportion of gypsum added to the cement was increased to a certain optimum value, but the increase was not as large as that obtained in the previous experiments by sieving cement. It is believed that fineness, sulphur trioxide content and possibly also the particle-size distribution can affect the strength obtained with a given cement, and further experiments are needed to determine the combination of fineness and sulphur trioxide content required to obtain a cement of maximum strength from clinker processed in a given way.
The composition of the ferrite phase in Portland cement
Authors: Midgley H. G.
Published: July 2012

Summary

A study of the composition of the ferrite phase present in commercial Portland cements has been made using powder X-ray diffraction techniques. From the results of an examination of thirty-one different samples, the most frequently occurring composition lies between 4CaO.Al2O3.Fe2O3 and 6CaO.Al2O3.2Fe2O3.
The early shrinkage characteristics of hand-placed concrete
Authors: Shacklock B. W.
Published: July 2012

Summary

The shrinkage characteristics of fresh concrete from 10 to 15 minutes up to 2 or more days after mixing have been examined for a variety of mixes suitable for compaction by hand. The apparatus used for these tests, which is still in the prototype stage of design, is described briefly.

Under drying conditions, apparent expansion of the concrete, thought to be caused primarily by settlement of the specimen in the apparatus, occurs immediately after placing up to a time between 1½ and 4½ hours after mixing; by this time the concrete has stiffened sufficiently not to flow. Shrinkage, varying between 1 × 10−4 and 13 × 10−4 takes place during the next 6 to 8 hours; there is then little further movement for a day or more. Concrete kept under water shows a greater apparent expansion, and no early shrinkage.

For mixes of approximately constant workability, the amount of early shrinkage under drying conditions appears to increase as the richness of the mix increases (with corresponding changes in the water/cement ratio), and it also increases as the amount of bleeding within the concrete decreases.