bluuebunny/crossref_metadata_2025 huggingface dataset:
HDAC Inhibitors Augmented Cell Migration and Metastasis through Induction of PKCs Leading to Identification of Low Toxicity Modalities for Combination Cancer Therapy
Authors: Lin Kuen-Tyng , Wang Yi-Wei , Chen Chiung-Tong , Ho Chun-Ming , Su Wen-Hui , Jou Yuh-Shan
Published: July 2012

Purpose: Histone deacetylase inhibitors (HDACi) are actively explored as new-generation epigenetic drugs but have low efficacy in cancer monotherapy. To reveal new mechanism for combination therapy, we show that HDACi induce cell death but simultaneously activate tumor-progressive genes to ruin therapeutic efficacy. Combined treatments to target tumorigenesis and HDACi-activated metastasis with low toxic modalities could develop new strategies for long-term cancer therapy.

Experimental Design: Because metastasis is the major cause of cancer mortality, we measured cell migration activity and profiled metastasis-related gene expressions in HDACi-treated cancer cells. We developed low toxic combination modalities targeting tumorigenesis and HDACi-activated metastasis for preclinical therapies in mice.

Results: We showed that cell migration activity was dramatically and dose dependently enhanced by various classes of HDACi treatments in 13 of 30 examined human breast, gastric, liver, and lung cancer cell lines. Tumor metastasis was also enhanced in HDACi-treated mice. HDACi treatments activated multiple PKCs and downstream substrates along with upregulated proapoptotic p21. For targeting tumorigenesis and metastasis with immediate clinical impact, we showed that new modalities of HDACi combined drugs with PKC inhibitory agent, curcumin or tamoxifen, not only suppressed HDACi-activated tumor progressive proteins and cell migration in vitro but also inhibited tumor growth and metastasis in vivo.

Conclusion: Treatments of different structural classes of HDACi simultaneously induced cell death and promoted cell migration and metastasis in multiple cancer cell types. Suppression of HDACi-induced PKCs leads to development of low toxic and long-term therapeutic strategies to potentially treat cancer as a chronic disease. Clin Cancer Res; 18(17); 4691–701. ©2012 AACR.
Unusually Large Numbers Needed to Treat for Radical Prostatectomy in Prostate Cancer Patients with PSA Velocity ≤2 ng/ml/Year
Authors: Scheerer J. , Kahabka P. , Altwein J.E. , Weißbach L.
Published: July 2012

Background: The numbers needed to treat (NNT) and the corresponding confidence intervals for patients with prostate cancer and defined annual PSA increases (PSA velocity, PSAV) have not been described previously. Aim: The objective of this study is to assess NNT, numbers needed to treat to harm and corresponding confidence intervals for radical prostatectomy (RP) in patients with prostate cancer defined as a PSAV ≤2 ng/ml/year. Methods: NNT following RP were estimated in risk groups defined by PSAV using mortality statistics and hazard ratios obtained in a noncontrolled trial. As no suited control group and no appropriate randomized trials were available for doing this calculation and as such trials are unlikely to become available in the near future we have calculated our NNTs as published previously by using relative risk reduction from an earlier randomized trial (RCT) comparing RP with watchful waiting (WW) [Can J Urol 2006;13(suppl 1):48–55]. Results: For preoperative PSAV >2 ng/ml/year, NNT for RP were estimated at 25, whereas for preoperative PSAV ≤2 ng/ml/year, the estimate was 618. The lower 95% confidence limits (NNTBl) were 9 and 126, respectively (treatment with benefit). The implications emerging from these findings are discussed by comparison with published NNT values from other RCTs. The lower 95% confidence limit for preoperative PSAV ≤2 ng/ml/year was found to be large in comparison. Conclusion: The NNT estimate obtained here for PSAV >2 ng/ml/year and its lower 95% confidence interval is comparable to values in other studies on prostate cancer for therapies considered to be effective, while the estimated NNT for patients with PSAV ≤2 ng/ml/year is large in comparison. We conclude that the benefits of RP for localized prostate cancer with preoperative PSAV ≤2 ng/ml/year may be considered small. There are several limitations to our findings, the most important of which lies in the fact that while PSAV remains significantly associated with outcomes, the predictive value of PSA measurements is low. While PSAV >2 ng/ml/year clearly indicates a need for surgery, a PSAV ≤2 ng/ml/year should imply further decision making.
Identification of nephropathy candidate genes by comparing sclerosis-prone and sclerosis-resistant mouse strain kidney transcriptomes
Authors: El-Meanawy Ashraf , Schelling Jeffery R , Iyengar Sudha K , Hayden Patrick , Barathan Shrinath , Goddard Katrina , Pozuelo Fatima , Elashi Essam , Nair Viji , Kretzler Matthias , Sedor John R
Published: July 2012

Background

The genetic architecture responsible for chronic kidney disease (CKD) remains incompletely described. The Oligosyndactyly (Os) mouse models focal and segmental glomerulosclerosis (FSGS), which is associated with reduced nephron number caused by the Os mutation. The Os mutation leads to FSGS in multiple strains including the ROP-Os/+. However, on the C57Bl/6J background the mutation does not cause FSGS, although nephron number in these mice are equivalent to those in ROP-Os/+ mice. We exploited this phenotypic variation to identify genes that potentially contribute to glomerulosclerosis.

Methods

To identify such novel genes, which regulate susceptibility or resistance to renal disease progression, we generated and compared the renal transcriptomes using serial analysis of gene expression (SAGE) from the sclerosis-prone ROP-Os/+ and sclerosis resistant C57-Os/+ mouse kidneys. We confirmed the validity of the differential gene expression using multiple approaches. We also used an Ingenuity Pathway Analysis engine to assemble differentially regulated molecular networks. Cell culture techniques were employed to confirm functional relevance of selected genes.

Results

A comparative analysis of the kidney transcriptomes revealed multiple genes, with expression levels that were statistically different. These novel, candidate, renal disease susceptibility/resistance genes included neuropilin2 (Nrp2), glutathione-S-transferase theta (Gstt1) and itchy (Itch). Of 34 genes with the most robust statistical difference in expression levels between ROP-Os/+ and C57-Os/+ mice, 13 and 3 transcripts localized to glomerular and tubulointerstitial compartments, respectively, from micro-dissected human FSGS biopsies. Network analysis of all significantly differentially expressed genes identified 13 connectivity networks. The most highly scored network highlighted the roles for oxidative stress and mitochondrial dysfunction pathways. Functional analyses of these networks provided evidence for activation of transforming growth factor beta (TGFβ) signaling in ROP-Os/+ kidneys despite similar expression of the TGFβ ligand between the tested strains.

Conclusions

These data demonstrate the complex dysregulation of normal cellular functions in this animal model of FSGS and suggest that therapies directed at multiple levels will be needed to effectively treat human kidney diseases.
The School Anxiety Scale-Teacher Report (SAS-TR): translation and psychometric properties of the Iranian version
Authors: Hajiamini Zahra , Mohamadi Ashraf , Ebadi Abbas , Fathi- Ashtiani Ali , Tavousi Mahmoud , Montazeri Ali
Published: July 2012

Background

The School Anxiety Scale-Teacher Report (SAS-TR) was designed to assess anxiety in children at school. The SAS-TR is a proxy rated measure and could assess social anxiety, generalized anxiety and also gives a total anxiety score. This study aimed to translate and validate the SAS-TR in Iran.

Methods

The translation and cultural adaptation of the original questionnaire were carried out in accordance with the published guidelines. A sample of students participated in the study. Reliability was estimated using internal consistency and test-retest analysis. Validity was assessed using content validity. The factor structure of the questionnaire was extracted by performing both exploratory and confirmatory factor analyses.

Results

In all 200 elementary students aged 6 to 10 years were studied. Considering the recommended cut-off values, overall the prevalence of high anxiety condition in elementary students was found to be 21 %. Cronbach's alpha coefficient for the Iranian SAS-TR was 0.92 and intraclass correlation coefficient (ICC) was found to be 0.81. The principal component analysis indicated a two-factor structure for the questionnaire (generalized and social anxiety) that jointly accounted for 55.3 % of variances observed. The confirmatory factory analysis also indicated a good fit to the data for the two-latent structure of the questionnaire.

Conclusion

In general the findings suggest that the Iranian version of SAS-TR has satisfactory reliability, and validity for measuring anxiety in 6 to 10 years old children in Iran. It is simple and easy to use and now can be applied in future studies.
Practices and opinions on nitrous oxide/oxygen sedation from dentists licensed to perform relative analgesia in Brazil
Authors: Daher Anelise , Hanna Renata Pinheiro Lima , Costa Luciane Rezende , Leles Cláudio Rodrigues
Published: July 2012

Background

Relative analgesia (RA), defined as the use of inhalation sedation with nitrous oxide and oxygen, is one of the most common pharmacological behavior management techniques used to provide sedation and analgesia for dental patients. This study aimed to assess RA licensed Brazilian dentists’ practices and opinions about nitrous oxide/oxygen sedation in the dental setting.

Methods

A cross sectional national survey was conducted with 281 dentists who were certified to perform RA, using an electronically mailed self-administered questionnaire containing closed questions about their practices and opinions regarding RA. Practice and opinion were individually analyzed by descriptive statistics. Non-parametric tests assessed the relationships between RA practice and independent variables. To test the interplay between practices and opinions, a k-means clusters analysis was used to divide the group for statistical comparisons.

Results

The response rate was 45.2%. Women made up 64.6% of the respondents, the mean age was 39.1 years (SD = 9.8), and the mean time since graduation in dentistry was 16 years (SD = 9.7). Seventy-seven percent of respondents reported the use of RA in clinical practice, most of them ‘sometimes’ (53.5%), and focusing more on adult patients. Patients with certain physical or mental deficiencies were indications associated with RA practice. ‘Equipment acquisition’ (p < 0.001) and ‘living in Southeast and South regions’ (p < 0.02) were also associated with RA practice. The scores for dentists’ opinions ranged from 15 to 41 points (mean 29.2, SD = 5.6), based on nine items scored from 1 to 5. Two clusters representing more favorable (n = 65) and less favorable (n = 55) opinions were established. Dentists who were women (p = 0.04), practiced RA in dental settings (p < 0.01) or practiced it frequently (p < 0.001), had more favorable opinions about RA.

Conclusion

Most of the RA licensed Brazilian dentists interviewed currently use RA. Current practice of RA and frequency of use determined the degree of favorable opinion about this inhalation sedation among this group of respondents.
Continuing Exposure to Low-Dose Nonylphenol Aggravates Adenine-Induced Chronic Renal Dysfunction and Role of Rosuvastatin Therapy
Authors: Yen Chia-Hung , Sun Cheuk-Kwan , Leu Steve , Wallace Christopher Glenn , Lin Yu-Chun , Chang Li-Teh , Chen Yung-Lung , Tsa Tzu-Hsien , Kao Ying-Hsien , Shao Pei-Lin , Hsieh Chi-Ying , Chen Yen-Ta , Yip Hon-Kan
Published: July 2012

Background

Nonylphenol (NP), an environmental organic compound, has been demonstrated to enhance reactive-oxygen species (ROS) synthesis. Chronic exposure to low-dose adenine (AD) has been reported to induce chronic kidney disease (CKD).

Methods

In this study, we tested the hypothesis that chronic exposure to NP will aggravate AD-induced CKD through increasing generations of inflammation, ROS, and apoptosis that could be attenuated by rosuvastatin. Fifty male Wistar rats were equally divided into group 1 (control), group 2 (AD in fodder at a concentration of 0.25%), group 3 (NP: 2 mg/kg/day), group 4 (combined AD & NP), and group 5 (AD-NP + rosuvastatin: 20 mg/kg/day). Treatment was continued for 24 weeks for all animals before being sacrificed.

Results

By the end of 24 weeks, serum blood urea nitrogen (BUN) and creatinine levels were increased in group 4 than in groups 1–3, but significantly reduced in group 5 as compared with group 4 (all p < 0.05). Histopathology scorings of renal-parenchymal and tubular damages were significantly higher in group 4 than in groups 1–3, but remarkably lower in group 5 compared with group 4 (all p < 0.01). Both gene and protein levels of inflammation, oxidative stress, ROS, and cellular apoptosis were remarkably higher in group 4 compared with groups 1–3, but lowered in group 5 than in group 4 (all p < 0.001). Conversely, both gene and protein levels of anti-oxidants, anti-inflammation and anti-apoptosis were markedly increased in group 5 compared with group 4 (all p < 0.001).

Conclusion

NP worsened AD-induced CKD that could be reversed by rosuvastatin therapy.
Forced oscillation of higher-order nonlinear neutral difference equations with positive and negative coefficients
Authors: Gao Yali , Sun Yuangong , Zha Bin , Liu Hongshuang
Published: July 2012

In this paper, we study the forced oscillation of the higher-order nonlinear difference equation of the form

Δm[x(n)−p(n)x(n−τ)]+q1(n)Φα(n−σ1)+q2(n)Φβ(n−σ2)=f(n),

wherem≥1,τ,σ1andσ2are integers,0<α<1<βare constants,Φ∗(u)=|u|∗−1u,p(n),q1(n),q2(n)andf(n)are real sequences withp(n)>0. By taking all possible values ofτ,σ1andσ2into consideration, we establish some new oscillation criteria for the above equation in two cases: (i)q1=q1(n)≤0,q2=q2(n)>0; (ii)q1≥0,q2<0.

MSC:39A10.
LXtoo: an integrated live Linux distribution for the bioinformatics community
Authors: Yu Guangchuang , Wang Li-Gen , Meng Xiao-Hua , He Qing-Yu
Published: July 2012

Background

Recent advances in high-throughput technologies dramatically increase biological data generation. However, many research groups lack computing facilities and specialists. This is an obstacle that remains to be addressed. Here, we present a Linux distribution, LXtoo, to provide a flexible computing platform for bioinformatics analysis.

Findings

Unlike most of the existing live Linux distributions for bioinformatics limiting their usage to sequence analysis and protein structure prediction, LXtoo incorporates a comprehensive collection of bioinformatics software, including data mining tools for microarray and proteomics, protein-protein interaction analysis, and computationally complex tasks like molecular dynamics. Moreover, most of the programs have been configured and optimized for high performance computing.

Conclusions

LXtoo aims to provide well-supported computing environment tailored for bioinformatics research, reducing duplication of efforts in building computing infrastructure. LXtoo is distributed as a Live DVD and freely available athttp://bioinformatics.jnu.edu.cn/LXtoo.
Genetic mismatch affects the immunosuppressive properties of mesenchymal stem cells in vitro and their ability to influence the course of collagen-induced arthritis
Authors: Sullivan Catherine , Murphy J Mary , Griffin Matthew D , Porter Ryan M , Evans Christopher H , O'Flatharta Cathal , Shaw Georgina , Barry Frank
Published: July 2012

Introduction

The immunological and homing properties of mesenchymal stem cells (MSCs) provide a potentially attractive treatment for arthritis. The objective of this study was to determine effects of genetic disparity on the immunosuppressive potential of MSCs in vitro and in vivo within collagen induced arthritis (CIA).

Methods

The ability of DBA/1, FVB and BALB/c MSC preparations to impact the cytokine release profile of CD3/CD28 stimulated DBA/1 T cells was assessed in vitro. The effect of systemically delivered MSCs on the progression of CIA and cytokine production was assessed in vivo.

Results

All MSC preparations suppressed the release of TNFα and augmented the secretion of IL-4 and IL-10 by stimulated DBA/1 T-cells. However, assessment of the ratio of IFNγ to IL-4 production indicated that the more genetically distant BALB/c MSCs had significantly less immunosuppressive capacity. Systemic delivery of BALB/c MSC resulted in an exacerbation of CIA disease score in vivo and a higher erosive disease burden. This was not seen after treatment with syngeneic or partially mismatched MSCs. An increase in serum levels of IL-1β was observed up to 20 days post treatment with allogeneic MSCs. An initial elevation of IL-17 in these treatment groups persisted in those treated with fully mismatched BALB/c MSCs. Over the course of the study, there was a significant suppression of serum IL-17 levels in groups treated with syngeneic MSCs.

Conclusions

These data demonstrate a significant difference in the immunosuppressive properties of syngeneic and allogeneic MSCs in vitro and in vivo, which needs to be appreciated when developing MSC based therapies for inflammatory arthritis.
Pilot Study of Meaningful Use of Electronic Health Records in Radiation Oncology
Authors: Shen Xinglei , Dicker Adam P. , Doyle Laura , Showalter Timothy N. , Harrison Amy S. , DesHarnais Susan I.
Published: July 2012

Most large academic radiation oncology practices have incorporated electronic health record systems into practice and plan to meet meaningful use requirements. Further work should focus on needs of smaller practices, and specific guidelines may improve widespread adoption.
Evaluating the Quality of Colorectal Cancer Care in the State of Florida: Results From the Florida Initiative for Quality Cancer Care
Authors: Siegel Erin M. , Jacobsen Paul B. , Malafa Mokenge , Fulp William , Fletcher Michelle , Lee Ji-Hyun , Smith Jesusa Corazon R. , Brown Richard , Levine Richard , Cartwright Thomas , Abesada-Terk Guillermo , Kim George , Alemany Carlos , Faig Douglas , Sharp Philip , Markham Merry-Jennifer , Shibata David
Published: July 2012

Although the quality of care delivered within the Florida Initiative for Quality Cancer Care practices seems to be high, several components of care were identified that warrant further scrutiny on a systemic level and at individual centers.
Economic and Microbiologic Evaluation of Single-Dose Vial Extension for Hazardous Drugs
Authors: Rowe Erinn C. , Savage Scott W. , Rutala William A. , Weber David J. , Gergen-Teague Maria , Eckel Stephen F.
Published: July 2012

Although savings would be substantial, and numerous drug shortages could be relieved if all medication in the vial were used for patient care, USP <797> is the standard by which all CSPs should be prepared.
Ethical Challenges: Caring for the Underinsured, Geographically Disadvantaged Patient
Authors: Riley Elizabeth C. , Moy Beverly
Published: July 2012

This vignette explores the challenges associated with treating patients who are underinsured and have social factors that create barriers to optimal care.
A physiotherapy perspective of musculoskeletal imaging in sport
Authors: Callaghan M J
Published: July 2012

This paper presents a physiotherapy perspective on the role that imaging is now playing in the diagnosis and management of musculoskeletal and sporting injuries. Although the Royal College of Radiologists and the UK Chartered Society of Physiotherapy were founded in the latter part of the nineteenth century, it is 100 years later that developments in the UK NHS have led to increased roles for non-medical healthcare professionals and allied health professionals, such as physiotherapists, in an extended clinical role. Physiotherapists, perhaps because of their knowledge of clinical and applied anatomy, have keenly taken up the opportunities offered to request and interpret imaging in its various forms; the most commonly available are plain radiography, musculoskeletal ultrasound and MRI. This has meant taking formal courses under the auspices of universities with mentorship and tutoring within the clinical setting, which are part of a continuing professional development. The ability to request several forms of imaging has enhanced physiotherapy practice and has increased the appreciation of the responsibilities which accompany this new role.
Oesophageal squamous cell carcinoma: relationship between fluorine-18 fludeoxyglucose positron emission tomography CT maximum standardised uptake value, metabolic tumour volume, and tumour, node and metastasis classification
Authors: Zhu W-Q , Sun X , Xing L , Li M , Yue J , Qu W , Sun X , Kong L , Yu J
Published: July 2012

Objectives: We aimed to evaluate the relationships between primary tumour, maximum standardised uptake value, metabolic tumour volume and seventh edition American Joint Committee on Cancer (AJCC) classification in oesophageal squamous cell carcinoma (OSCC) patients.

Methods: Fluorine-18 fludeoxyglucose (18F-FDG) positron emission tomography (PET)-CT scans of 41 consecutive newly diagnosed OSCC patients were retrospectively reviewed. Maximum standard uptake value (SUVmax) and metabolic tumour volume (MTV) were recorded. Two-tailed Spearman's correlation was used to analyse the relationships between the metabolic parameters and the AJCC staging system.

Results: Positive correlations were observed between SUVmax, MTV and tumour (T) stage, in addition to node (N) stage and AJCC stage. Both metabolic parameters were independent variables that significantly affected the N stage and AJCC stage, and SUVmax was the only independent variable that significantly affected the T stage.

Conclusion: The metabolic parameters derived from 18F-FDG PET-CT were positively correlated with T, N and AJCC stage in primary OSCC. Our findings may suggest a complementary role of these parameters to seventh-edition AJCC staging in the prognostication of OSCC patients.
Research methods of ultrafine steels after equal channel angular pressing
Authors: Petrova N. , Ivanov A. , Lukin Ev.
Published: July 2012

Steel subjected to ECAP has very high mechanical characteristics. The goal of the present work is to investigate the influence of thermal treatment on steel cold brittle resistance after ECAP. The influence of equal-channel angular pressing and heat treatment on structure-phase state and mechanical characteristics of Fe360 is investigated. Also, the investigations of deformation in metals and steels are carried out with the use of infrared imaging cameras. The results concerned with the evaluation of storage energy in the process of plastic deformation of the structural low carbon steel are presented.
Column leaching test to study effect of cover of fly ash for preventing acid mine drainage from coal waste
Authors: Baoguo Ma , Mingliang Zhang , Zhenqi Hu
Published: July 2012

Coal waste that releases highly acidic, sulfate and metals rich drainage is a serious environmental problem which causes the contamination of surface and ground water as well as soils in coal mining areas in China. In order to study the effect of using fly ash for preventing acid-mine drainage and controlling heavy metals contamination from coal waste, two column leaching tests were conducted to determine if a cover of fly ash could be used for the control of acid-mine drainage from coal waste. We investigated the effect of the cover of fly ash on controlling acid, sulfate and heavy metals contamination from coal waste. The results from the experimental data analyses show that the cover of fly ash can effectively immobilize cadmium, copper, iron, lead and zinc in acid-mine drainage from coal waste, increase the pH value from 2.0 to 7.5 and decrease Eh from 249 mV to 148 mV, EC from 5.22 mS/cm to 1.05 mS/cm and SO42- concentrations from 12911.7 mg/L to 881.4 mg/L of acid-mine drainage from coal waste. The immobilization rate of heavy metals reached 99%. The oxidation of sulfide minerals in coal waste was prevented by the cover of fly ash, which favors the generation of alkalinity, the decrease of the population of Thiobacillus ferrooxidans, the heavy metals immobilization by precipitation inside the column, and the halt of the oxidation process of sulfide through iron coating on the surface of sulfide minerals in coal waste. The cover of fly ash can effectively control acid-mine drainage and heavy metals contamination from coal waste in situ treatment systems.
A Note on a Group Preference Axiomatization with Cardinal Utility
Authors: Dias Luis C. , Sarabando Paula
Published: July 2012

Kenneth Arrow's work on social welfare proposed a set of conditions that a function to aggregate ordinal preferences of the members of a group should satisfy, proving that it was not possible to satisfy all these assumptions simultaneously. Later, Ralph Keeney adapted these conditions and proposed a cardinal utility axiomatization for the problem of aggregating the utility functions. This note discusses in particular the condition of nondictatorship. It proposes stronger formulations for this condition to limit the maximum influence that an individual can have, and it presents the corresponding characterization of compliant group cardinal utility functions. An extension to address coalitions of individuals acting strategically is also discussed.
Regeneration through Misuse: Rugged Consumerism in Contemporary American Culture
Authors: Malewitz Raymond
Published: July 2012

This essay charts the emergence of “rugged consumers” in contemporary American culture: skilled laborers who confront the disappearance of manufacturing jobs during the late twentieth and early twenty-first centuries and the accompanying sense of labor's marginality in American society. Although they are alienated from sites of industrial productivity, rugged consumers find alternative means of practicing their skills by creatively misusing, repairing, and repurposing the commodities in their environments. At the same time, they ennoble such actions by modeling them on the intertwined American myths of primal nature and rugged individualism. Whether in literature or in the broader culture, American rugged consumers thus mediate between the mythic models of self-sufficiency celebrated by the country's older, frontier capitalism and the postindustrial realities of the present. The essay posits four provisional categories of rugged consumerism, ranging from the hypermasculine weaponization of unlikely objects to the (re)creation of environmentally sustainable interior designs.
Writ in Water:Far Tortugaand the Crisis of the Marine Environment
Authors: Brayton Dan
Published: July 2012

ENVIRONMENTAL CATASTROPHE HAUNTS THE EARLY TWENTY-FIRST CENTURY, OUR MENTAL MAPS OF SHRINKING RAINFORESTS MATCHED BY images of melting icecaps and dying polar bear cubs. As the thawing tundra releases an amplifying store of methane, the goal of Bill McKibben's350.org, to reduce carbon in the earth's atmosphere to 350 parts per million, seems wildly optimistic.1So, too, does much of the discourse of sustainability. How can humans depend on the biosphere's capacity to regenerate, having already destroyed entire ecosystems and caused countless extinctions and continuing to do so at an accelerating rate? Isn't it already too late? What tends to get lost in the linked discourses of climate change and sustainability is the rising seawater—salt water, the stuff that covers seventy percent of the planet's surface. If the ocean, as Christopher Connery claims, “has long functioned as Western capitalism's primary myth element” (686), then literary scholarship engaged with the discourse of sustainability should reexamine narratives of oceanic catastrophe.
Briefing: Education to prepare for the practice of forensic engineering
Authors: Ratay Robert T.
Published: July 2012

The education and practice of forensic structural engineering should have three goals: first, and foremost, to reduce the number and magnitude of failures; second, to apply effective and reliable methods of forensic analysis; and third, to provide technical support for the fair resolution of disputes.
The effect of chlorides upon the hydration of Portland cement and upon some clinker minerals
Authors: Skalný J. , Odler I.
Published: July 2012

Summary

The influence of various chlorides upon the hydration process of Portland cement and of calcium chloride upon some clinker minerals has been studied by means of chemical and thermoanalytical methods and X-ray diffractometry. From the results, conclusions may be drawn regarding the mechanism of the influence of chlorides upon the hydration process.
Fatigue of concrete and its effect upon prestressed concrete beams
Authors: Sawko F. , Saha G. P.
Published: July 2012

Summary

The paper reviews the extensive literature on fatigue of concrete and summarizes the most important conclusions. Fatigue hardening of the compressive zone and fatigue softening of the tension zone are examined in detail, and the authors' tests to verify these effects are described. The effects are illustrated by suggested transformations in equivalent section properties in members subjected to fatigue. The increase or decrease of fatigued strength is plotted against maximum stress in the fatigue stress range. It is finally concluded that, with a load factor of 2 specified in the Code of Practice for prestressed concrete, fatigue is never likely to be a design criterion for strength.
Bending and torsion of reinforced concrete beams
Authors: Goode C. D. , Helmy M. A.
Published: July 2012

Summary

Combined bending and torsion tests were carried out on 55 rectangular concrete beams to study the influence of concrete strength, reinforcement and the intensity of applied bending moment on their torsional behaviour and strength. Two series contained only longitudinal reinforcement, two contained longitudinal reinforcement and stirrups inclined at 45°, and six series contained longitudinal reinforcement and vertical stirrups. The intensity of applied bending moment had little effect on the initial torsional stiffness of the beams or on the torque at which diagonal cracking started. A theory is outlined for determining the mode of failure and ultimate strength under bending and torsion and this is compared with the results of these tests and those of other investigators.
A creep rig for testing concrete under multiaxial compressive stress
Authors: Jordaan I. J. , Illston J. M.
Published: July 2012

Summary

The paper describes the design and testing of apparatus for the study of time-dependent strains in concrete under sustained multiaxial loading. The apparatus is designed to measure the three orthogonal strains under three independent compressive stresses. Special attention is given to the problem of frictional effects between the loading platens and the concrete specimens.
The ultimate moment of resistance of unbonded prestressed concrete beams
Authors: Pannell F. N.
Published: July 2012

Synopsis

The method set out in CP 115: 1959 for the determination of the ultimate moment of resistance of unbonded prestressed concrete beams is simple but inaccurate. Alternative methods have been proposed which are more tedious to use, but because (in common with CP 115) they fail to consider.a factor which proves to be of importance, namely the span/depth ratio of the beam, the accuracy of prediction is little better. This is demonstrated by the results of tests on 38 beams, which are then used to investigate the validity of a revised theory. A substantial increase in accuracy of prediction is obtained, and this is confirmed by the results of 19 independent tests. Proposals are put forward for a safe design approach. The equations proposed predict the ultimate moment of resistance of the 57 test beams as having a mean value of 0·995 Mtest, and a coefficient of variation of 4·7%.
On the necessity of a non-slip mechanism between steel and concrete in the region of a crack
Authors: Brown Colin B.
Published: July 2012

Synopsis

Experiments have suggested that the width of a crack occurring in reinforced concrete in flexure becomes zero around the reinforcement. In this paper it is shown that the bond mechanism of no-slip, although obviously sufficient, is not necessary in order that these closed regions of a crack may occur. This allows theories of cracking to proceed unhampered by unduly restrictive conditions on bond.
Strength and deformation of concrete in uniaxial tension and compression
Authors: Johnston C. D.
Published: July 2012

Synopsis

The paper examines the influence of mix parameters upon the strength and deformation of plain concrete subjected to uniaxial tensile or compressive stress. Parameters considered are the effective water/cement ratio, aggregate/cement ratio, aggregate maximum size and grading defined in terms of mean particle size, and the strength, elastic modulus and crushing value (B.S. 812) of the coarse aggregate. Tensile and compressive strength, tensile strain at failure and compressive strain at 50 % compressive strength are related to each parameter in turn, often by expressing the values in relative terms. The results obtained from 94 mixes are used to develop charts which permit reasonably accurate prediction of any of the four properties listed above for a wide range of mixes.
Some observations on the components of creep in concrete
Authors: Parrott L. J.
Published: July 2012

Synopsis

Some experimental creep data are analysed with reference to recent ideas that creep can be separated into recoverable and irrecoverable basic creep and recoverable and irrecoverable drying creep. Data on lateral strain behaviour are also presented. It is shown that this division of creep on the basis of axial strain measurements is not satisfactory. The implications of the results for future work on creep under uniaxial and multiaxial loading are indicated.
The behaviour of prestressed concrete portal frames as influenced by creep and temperature
Authors: Krishnamoorthy S. , England G. L. , Yu C. W.
Published: July 2012

Synopsis

This paper describes experiments staged to observe the long-term effects of creep upon the behaviour of axially prestressed, two-pinned portal frames subjected to long-sustained elevated temperature regimes. The test apparatus is described and experimental results are presented. It is concluded that non-uniform temperatures significantly affect the deflection behaviour of the structures and cause internal stresses and moments to undergo marked changes with time. Elastic theory is incapable a;j'estimating these changes. Other theories which recognize creep are therefore necessary.
The shear strength of uniformly loaded beams without web reinforcement
Authors: Ojha S. K.
Published: July 2012

Synopsis

This paper describes an iterative method of calculating the failure load of uniformly loaded reinforced concrete rectangular beams without shear reinforcement. Use is made of basic equations, derived in an earlier paper. By utilizing the “distortion energy principle”, it has been possible for the first time to predict the section of failure mathematically, and so also the inclination of the shear crack. In developing a failure criterion for the concrete of the compression zone, due weight has been given to the vertical stresses due to loading. The calculated results show fairly good agreement with experimental evidence.
Effects of lateral reinforcement upon the strength and deformation properties of concrete
Authors: Sargin M. , Ghosh S. K. , Handa V. K.
Published: July 2012

Synopsis

Confinement of concrete by rectilinear lateral reinforcement is discussed. An experimental investigation is described in which the main variables were: concrete strength; size, spacing and grade of lateral reinforcement; strain gradient; and thickness of cover. In the analysis of test results, laterally reinforced specimens are treated as composite members consisting of core and cover. The parameters of an analytical stress-strain relationship, which was found to describe the mechanical properties of plain and laterally reinforced concrete adequately, are determined from a regression analysis of the test results. The experimental results are compared with the strength of confined concrete as predicted by (1) a formula based on a theoretical analysis, and (2) an equation which unifies several previously proposed formulae giving the strength of laterally reinforced concrete.
Improvement in long-term bulk storage of cement for a concrete laboratory
Authors: Lunt B. G. , Van Dijk J.
Published: July 2012

Synopsis

The paper describes a simple and economical system which has been successfully used to preserve in good condition cement stored in a silo for a long period. The system also enables any leaks which may occur in the silo to be detected rapidly.
An apparatus for curing to a predetermined time-temperature function
Authors: Bell F. H.
Published: July 2012

Synopsis

An automatically controlled water-curing apparatus has been designed and built at a cost for materials of $400. It can be programmed to follow predetermined time-temperature curves between 8 and 60°C to within ± 1°C, and tests with the tank unloaded have shown that, in a heating period, a temperature change from 8 to 60°C can be achieved in 7 hours. In a cooling period, the temperature can be reduced from 60 to 8°C in 55 hours.
The effect of moisture content upon the elasticity of hardened cement paste
Authors: Parrott L. J.
Published: July 2012

Synopsis

Data on the effect of moisture content upon the axial and lateral elastic compliances of hardened cement pastes with a range of porosities are presented. A number of explanations for the results are examined including one which postulates that calcium silicate hydrate can dehydrate at high humidities. The dehydration mechanism is consistent with the author's results and might help to explain data by other investigators on bulk modulus, shrinkage and sorption behaviour of hardened cement paste.
The effect of different test procedures upon the indicated strength of concrete blocks in compression
Authors: Roberts J. J.
Published: July 2012

Synopsis

Although the use of loose fibre-board caps with single blocks may increase the variation within a set of results when compared with mortar capping, the amount will depend largely upon the skill and experience of the mortar-capping operative. From an economic viewpoint, the board-capped single block specimen offers several advantages, and the sample size may be adjusted to give the required level of accuracy to the determination of block strength. The relationship between the results of tests on mortar- and board-capped specimens may be calculated, and both forms of test related directly to the performance of concrete block work walls.
Methods of measuring the air and water permeability of concrete
Authors: Figg J. W.
Published: July 2012

Synopsis

This paper describes simple and portable apparatus for estimating the air and water permeability of concrete in situ. The methods used require a small hole 5·5 mm diameter and 30 mm deep to be drilled in the specimen. The hole is plugged with a catalysed liquid silicone rubber which sets to give a resilient seal to the small cavity in the concrete. A gas- and liquid-tight connection is obtained by inserting a hypodermic needle through the silicone ruhber. The results obtained using the apparatus on laboratory-prepared concrete show good correlation with both water/cement ratio and compressive strength; it is suggested that the proposed methods may prove useful for predicting the durability of concrete. The techniques are sensitive enough to detect differences in aggregate porosity. The moisture content of the concrete has a major injiuence on the readings; a miniaturized moisture meter is being developed so that corrections can be made for this effect.
A method for determining the shear strength of reinforced concrete beams with small av/d ratios
Authors: Desayi Prakash
Published: July 2012

Synopsis

Some of the limitations of the methods available for determining the ultimate strength of reinforced concrete beams with a < av/d < 1·0 are discussed in the light of the results of an experimental programme. A method for determining the shear strength of such beams is presented which takes into account the splitting strength of concrete and the influence of any steel crossing the failure crack. The nominal ultimate shear stress calculated by the proposed method is found to be comparable with a total of 161 test results on concrete and plaster of Paris beams reported in the literature, including tests by the author on reinforced concrete beams without web reinforcement.
Free and bound water in cement pastes
Authors: Harris D. H. C. , Windsor C. G. , Lawrence C. D.
Published: July 2012

Synopsis

Quasi-elastic neutron scattering has been used to investigate the nature of the bonding of water molecules in cement pastes of various porosities. The experiments show that it is possible, to quite a good approximation, to speak of the water as being either ‘bound’ with negligible mobility, or ‘free’ with the full mobility of bulk water. There is no evidence for any hydration state of intermediate mobility. The ratio offree to total water in saturated specimens given by these experiments is considerably less than that obtained from conventional weight-loss measurements under controlled drying.
Uniaxial tensile creep and failure of concrete
Authors: Domone P. L.
Published: July 2012

Synopsis

This paper describes a series of experiments carried out on concrete under uniaxial tensile stress, using a test method developed previously. The properties assessed include the effect of mix proportions and curing conditions upon the short-term failure stress and strain and upon the tensile creep under a load of 35% of the ultimate short-term strength. The effect of variable humidity states upon the tensile creep was also investigated, and the results interpreted from the viewpoint of creep hypotheses for compressive loading. Where possible, the observed effects are related to the microstructure of cement gel. Finally, the effects upon creep of the level of loading and of the long-term strength of concrete in tension have been determined, and compared with the established behaviour in compression.
The prediction of crack widths in reinforced concrete beams
Authors: Albandar F. A-A. , Mills G. M.
Published: July 2012

Synopsis

Two parameters, concrete cover and average effective area of concrete surrounding each bar, were varied in a factorial experiment on rectangular reinforced concrete beams. Crack widths were measured from full-scale photographic plates taken of the tensile region for the series of nine beams loaded to a selected steel stress. Comparisons are made between the observed mean and maximum crack widths, predicted values from previously suggested formulae, and a new formula proposed by the authors which incorporates the two parameters varied together with the average concrete strain at the level considered.
The strip method of slab design: unique or lower-bound solutions?
Authors: Fernando J. S. , Kemp K. O.
Published: July 2012

Synopsis

The yield conditions in moment fields produced by the strip method of slab design are examined and rules are derived for yield lines in a collapse mechanism to be consistent with the unique solution. It appears that the strip method does not always produce a unique solution for the collapse load, but the exceptions are rare.
Some experimental studies on a reinforced concrete slab-beam system
Authors: Datta T. K. , Ramesh C. K.
Published: July 2012

Synopsis

Experimental tests on nineteen single-panel square slab-beam models are reported in order to study the enhancement of the load-carrying capacity due to the development of compressive membrane forces. The variables included are the percentage of reinforcement, and the degree of edge restraint at the surrounds of the slab provided by the varying lateral rigidity of the edge beams. The ultimate loads of the models are predicted by a method proposed by the authors and compared with the experimentally obtained values for good agreement. An empirical recommendation for the enhanced capacity due to T-beam action alone, which induces some precompression in the slab, is also made.
Shear strength of prestressed concrete beams without web reinforcement
Authors: Mahgoub M. O.
Published: July 2012

Synopsis

This paper represents a detailed study, based on dimensional analysis, of the factors which seem to affect the shear strength of prestressed concrete beams under one- or two-point loading. Fifty-eight pre-tensioned concrete beams of seven different cross-sections were tested. The load at the first inclined tension crack rather than the ultimate load is taken to limit the capacity of these beams in shear because of the indeterminate factors involved in calculating the latter. An expression for predicting this inclined cracking load is derived and compared, for specific cases, with other published expressions. Other published test results are in a good agreement with the derived expression.
Influence of binary aggregate proportions upon some concrete properties
Authors: Nwokoye Daniel N.
Published: July 2012

Synopsis

The paper reports work continuing two earlier researches and exploiting further the use of ultrasonic-pulse-velocity tests to examine the internal structure of concrete and its influence upon certain physical and mechanical properties. It is found that binary aggregate proportions affect (a) the relationships between paste pulse velocity and cube strength and (b) the dynamic elastic moduli of cement paste; mortar, quasi-mortar {cement paste plus coarse aggregate) and concrete phases and also have some influence upon the workability of concrete. For the particular mixes tested, the maximum dynamic modulus, maximum concrete pulse velocity and the maximum loose and rodded bulk densities of the combined aggregates all occurred at the optimum coarse-aggregate content for workability. The test further confirmed that, in predicting the elastic modulus of concrete, the elastic modulus of the quasimortar merits as much consideration as that of the mortar itself. The curves for both moduli due to changes in the volume fraction of sand and coarse aggregates intersect at a point influenced by the age of the concrete
Dynamic versus static artificial neural network model for masonry creep deformation
Authors: El-Shafie Ahmed , Aminah Siti
Published: July 2012

One of the inherent modelling problems in structural engineering is creep of quasi-brittle materials such as concrete and masonry. The creep strain represents the non-instantaneous strain that occurs with time when stress is sustained. It has long been known that creep in brickwork results in deformations that increase gradually over time, and dependable and accurate prediction models for the long-term, time-dependent creep deformation of brickwork structures are, therefore, required. Several models, with limited accuracy, have been developed over recent decades to predict creep in concrete and masonry structures. The stochastic nature of creep deformation and its reliance on a large number of uncontrolled parameters (e.g. relative humidity, time of load application, stress level) make the process of prediction difficult and the development of accurate mathematical models almost impossible. Artificial neural networks have been introduced as an efficient modelling technique for applications incorporating a large number of variables and have proven successful in many cases, especially in problems for which the characteristics of the process are difficult to describe using mathematical models. This study introduces a creep prediction model, based on non-linear autoregression with exogenous inputs (Narx), which is able to detect and consider time dependency (which is the major factor in creep deformation of brickwork structures) within its architecture. The performance of the proposed Narx model was verified with experimental creep data from brickwork assemblages collected over the last 15 years. The results show that the accuracy of the Narx model outperforms existing artificial neural network models and is able to achieve a prediction error of less than 12%, strongly suggesting that the Narx model is more suitable for modelling a time-varying process such as creep prediction.