bluuebunny/crossref_metadata_2025 huggingface dataset:
Cost effectivenes of erlotinib versus chemotherapy for first-line treatment of non small cell lung cancer (NSCLC) in fit elderly patients participating in a prospective phase 2 study (GFPC 0504)
Authors: Christos Chouaid , Hervé Le Caer , Chrystelle Locher , Cecile Dujon , Pascal Thomas , Jean Bernard Auliac , Isabelle Monnet , Alain Vergnenegre ,   and GFPC 0504 Team
Published: July 2012

Background

The median age of newly diagnosed patients with non-small cell lung cancer (NSCLC) is 67 years, and one-third of patients are older than 75 years. Elderly patients are more vulnerable to the adverse effects of chemotherapy, and targeted therapy might thus be a relevant alternative. The objective of this study was to assess the cost-effectiveness of erlotinib followed by chemotherapy after progression, compared to the reverse strategy, in fit elderly patients with advanced NSCLC participating in a prospective randomized phase 2 trial (GFPC0504).

Methods

Outcomes (PFS and overall survival) and costs (limited to direct medical costs, from the third-party payer perspective) were prospectively collected until second progression. Costs after progression and health utilities (based on disease states and grade 3–4 toxicities) were derived from the literature.

Results

Median overall survival, QALY and total costs for the erlotinib-first strategy were respectively 7.1 months, 0.51 and 27 734 €, compared to 9.4 months, 0.52 and 31 688 € for the chemotherapy-first strategy. The Monte Carlo simulation demonstrates that the two strategies do not differ statistically.

Conclusion

In terms of cost effectiveness, in fit elderly patients with NSCLC, erlotinib followed by chemotherapy compares well with the reverse strategy.
Optimal pilot symbol power allocation under time-variant channels
Authors: Šimko Michal , Wang Qi , Rupp Markus
Published: July 2012

Nowadays, most wireless communication systems employ coherent demodulation on the receiver side. Under this circumstance, part of the available transmission resource is reserved and utilized for channel estimation, referred to as pilot symbols. In recent standards, for example long-term evolution (LTE), a certain adjustment is allowed for the power radiated on the pilot symbols. This additional degree of freedom creates space for a further optimization of the system performance. In this article, we consider an orthogonal frequency division multiplexing system and investigate how to distribute the available power between data symbols and pilot symbols under transmissions over time-variant channels so that the overall throughput is maximized. We choose the post-equalization signal-to-interference and noise ratio as the cost function and solve the problem analytically. Simulation results obtained by the Vienna LTE simulator are consistent with the analytical results. With an optimal power distribution between data and pilot symbols, a throughput increase of around 10% can be achieved compared to a system with evenly distributed power between data and pilot symbols.
Subcutaneous metastases from colon cancer: a case report
Authors: Lo Russo Giuseppe , Accarpio Fabio , Spinelli Gian Paolo , Miele Evelina , Borrini Francesco , Cerbone Linda , Stati Valeria , Prinzi Natalie , Strudel Martina , Sibio Simone , Tomao Silverio
Published: July 2012

Introduction

Dukes A stages of colorectal cancer are rarely reported to metastasize. Subcutaneous or skin metastases from colon cancer are rare events and usually indicate widespread disease.

Case presentation

We present the case of a 72-year-old Caucasian woman with Dukes A colorectal cancer at diagnosis and, three years later, a single secondary subcutaneous involvement with no other metastatic sites. The description of this case is supported by critical analysis of its clinical, radiological and pathological features. Our report illustrates that diagnosis can be difficult and controversial when relapse occurs in early stage patients and at uncommon sites.

Conclusion

The unusual and aggressive course of the reported disease stresses the importance of intensive follow-up in colorectal cancer patients with good prognostic factors.
Indian hedgehog gene transfer is a chondrogenic inducer of human mesenchymal stem cells
Authors: Steinert Andre F , Weissenberger Manuel , Kunz Manuela , Gilbert Fabian , Ghivizzani Steven C , Göbel Sascha , Jakob Franz , Nöth Ulrich , Rudert Maximilian
Published: July 2012

Introduction

To date, no single most-appropriate factor or delivery method has been identified for the purpose of mesenchymal stem cell (MSC)-based treatment of cartilage injury. Therefore, in this study we tested whether gene delivery of the growth factor Indian hedgehog (IHH) was able to induce chondrogenesis in human primary MSCs, and whether it was possible by such an approach to modulate the appearance of chondrogenic hypertrophy in pellet cultures in vitro.

Methods

First-generation adenoviral vectors encoding the cDNA of the human IHH gene were created by cre-lox recombination and used alone or in combination with adenoviral vectors, bone morphogenetic protein-2 (Ad.BMP-2), or transforming growth factor beta-1 (Ad.TGF-β1) to transduce human bone-marrow derived MSCs at 5 × 102 infectious particles/cell. Thereafter, 3 × 105 cells were seeded into aggregates and cultured for 3 weeks in serum-free medium, with untransduced or marker gene transduced cultures as controls. Transgene expressions were determined by ELISA, and aggregates were analysed histologically, immunohistochemically, biochemically and by RT-PCR for chondrogenesis and hypertrophy.

Results

IHH, TGF-β1 and BMP-2 genes were equipotent inducers of chondrogenesis in primary MSCs, as evidenced by strong staining for proteoglycans, collagen type II, increased levels of glycosaminoglycan synthesis, and expression of mRNAs associated with chondrogenesis. IHH-modified aggregates, alone or in combination, also showed a tendency to progress towards hypertrophy, as judged by the expression of alkaline phosphatase and stainings for collagen type X and Annexin 5.

Conclusion

As this study provides evidence for chondrogenic induction of MSC aggregates in vitro via IHH gene delivery, this technology may be efficiently employed for generating cartilaginous repair tissues in vivo.
Results of a phase II open-label, non-randomized trial of cisplatin chemotherapy in patients with BRCA1-positive metastatic breast cancer
Authors: Byrski Tomasz , Dent Rebecca , Blecharz Pawel , Foszczynska-Kloda Malgorzata , Gronwald Jacek , Huzarski Tomasz , Cybulski Cezary , Marczyk Elzbieta , Chrzan Robert , Eisen Andrea , Lubinski Jan , Narod Steven A
Published: July 2012

Introduction

The purpose of this investigation was to evaluate the efficacy of cisplatin chemotherapy in BRCA1 mutation carriers with metastatic breast cancer.

Methods

In a phase II, open-label study, 20 patients with metastatic breast cancer who carried a mutation in BRCA1 were treated with cisplatin 75 mg/m2 intravenously every 3 weeks as part of a 21-day cycle for 6 cycles. Restaging studies to assess response were performed after cycles 2 and 6, and every three months thereafter.

Results

Between July 2007 and January 2009, 20 patients were enrolled. Baseline characteristics were as follows: 65% had prior adjuvant chemotherapy, 55% had prior chemotherapy for metastatic breast cancer; mean age was 48 years (ranges 32 to 70); 30% estrogen receptor (ER) or progesterone receptor (PR)+, 70% ER/PR/Human Epidermal Growth Factor Receptor 2 (HER2)- and 0% HER2+. Overall response rate was 80%; nine patients experienced a complete clinical response (45%) and seven experienced a partial response (35%). Overall survival was 80% at one year, 60% at two years and 25% at three years. Four of the 20 patients are alive four years after initiating treatment. The median time to progression was 12 months. The median survival from the start of cisplatinum treatment was 30 months. Cisplatin-related adverse events, including nausea (50%), anemia (5%) and neutropenia (35%) were mostly mild to moderate in severity.

Conclusions

This phase II study demonstrates that cisplatin chemotherapy has high activity in women with a BRCA1 mutation and metastatic breast cancer and is generally well tolerated.

Trial registration

This trial is registered retrospectively on the clinical trials website ClinicalTrials.gov. The identifier is NCT01611727.
Prolactin-induced protein mediates cell invasion and regulates integrin signaling in estrogen receptor-negative breast cancer
Authors: Naderi Ali , Meyer Michelle
Published: July 2012

Introduction

Molecular apocrine is a subtype of estrogen receptor (ER)-negative breast cancer that is characterized by a steroid-response gene signature. We have recently identified a positive feedback loop between androgen receptor (AR) and extracellular signal-regulated kinase (ERK) signaling in this subtype. In this study, we investigated the transcriptional regulation of molecular apocrine genes by the AR-ERK feedback loop.

Methods

The transcriptional effects of AR and ERK inhibition on molecular apocrine genes were assessed in cell lines. The most regulated gene in this process, prolactin-induced protein (PIP), was further studied using immunohistochemistry of breast tumors and xenograft models. The transcriptional regulation of PIP was assessed by luciferase reporter assay and chromatin immunoprecipitation. The functional significance of PIP in cell invasion and viability was assessed using siRNA knockdown experiments and the mechanism of PIP effect on integrin-β1 signaling was studied using immunoblotting and immunoprecipitation.

Results

We found that PIP is the most regulated molecular apocrine gene by the AR-ERK feedback loop and is overexpressed in ER-/AR+ breast tumors. In addition, PIP expression is regulated by AR-ERK signaling in xenograft models. These observations are explained by the fact that PIP is a target gene of the ERK-CREB1 pathway and is also induced by AR activation. Furthermore, we demonstrated that PIP has a significant functional role in maintaining cell invasion and viability of molecular apocrine cells because of a positive regulatory effect on the Integrin-ERK and Integrin-Akt signaling pathways. In fact, PIP-knockdown markedly decreases the phosphorylation of ERK, Akt, and CREB1. Importantly, PIP knockdown leads to a marked reduction of integrin-β1 binding to ILK1 and ErbB2 that can be reversed by the addition of fibronectin fragments.

Conclusions

We have identified a novel feedback loop between PIP and CREB1 mediated through the Integrin signaling pathway. In this process, PIP cleaves fibronectin to release fragments that activate integrin signaling, which in turn increases PIP expression through the ERK-CREB1 pathway. In addition, we demonstrated that PIP expression has a profound effect on cell invasion and the viability of molecular apocrine cells. Therefore, PIP signaling may be a potential therapeutic target in molecular apocrine breast cancer.
Diversification of a Protein Kinase Cascade: IME-2 Is Involved in Nonself Recognition and Programmed Cell Death in Neurospora crassa
Authors: Hutchison Elizabeth A , Bueche Joanna A , Glass N Louise
Published: July 2012

Kinase cascades and the modification of proteins by phosphorylation are major mechanisms for cell signaling and communication, and evolution of these signaling pathways can contribute to new developmental or environmental response pathways. The Saccharomyces cerevisiae kinase Ime2 has been well characterized for its role in meiosis. However, recent studies have revealed alternative functions for Ime2 in both S. cerevisiae and other fungi. In the filamentous fungus Neurospora crassa, the IME2 homolog (ime-2) is not required for meiosis. Here we determine that ime-2 interacts genetically with a transcription factor vib-1 during nonself recognition and programmed cell death (PCD). Mutations in vib-1 (Δvib-1) suppress PCD due to nonself recognition events; however, a Δvib-1 Δime-2 mutant restored wild-type levels of cell death. A role for ime-2 in the post-translational processing and localization of a mitochondrial matrix protein was identified, which may implicate mitochondria in N. crassa nonself recognition and PCD. Further, Δvib-1 strains do not produce extracellular proteases, but protease secretion reverted to near wild-type levels in a Δvib-1 Δime-2 strain. Mass spectrometry analysis revealed that the VIB-1 protein is phosphorylated at several sites, including a site that matches the IME-2 consensus. The genetic and biochemical data for ime-2 and vib-1 indicate that IME-2 is a negative regulator of VIB-1 and suggest parallel negative regulation by IME-2 of a cell death pathway in N. crassa that functions in concert with the VIB-1 cell death pathway. Thus, IME2 kinase function has evolved following the divergence of S. cerevisiae and N. crassa and provides insight into the evolution of kinases and their regulatory targets.
DNA Repair Pathway Choice Is Influenced by the Health of Drosophila melanogaster
Authors: Wang Alethea D , Agrawal Aneil F
Published: July 2012

In nature, individuals vary tremendously in condition and this may be an important source of variation in mutation rate. Condition is likely to affect cell state and thereby impact the amount of DNA damage sustained and/or the way it is repaired. Here, we focus on DNA repair. If low-condition individuals are less capable of devoting the same level of resources to accurate repair, they may suffer higher mutation rates. However, repair decisions are also governed by various aspects of cell physiology, which may render the prediction that “higher-condition individuals use better repair mechanisms” too simplistic. We use a larval diet manipulation in Drosophila melanogaster to create high- and low-condition individuals and then contrast their relative usage of three repair pathways [homologous recombination (HR), single-strand annealing (SSA), and nonhomologous end joining (NHEJ)] that differ in their mechanistic requirements and their mutational consequences. We find that low-condition flies are more likely than high-condition flies to use the most conservative of these three repair pathways, suggesting that physiological constraints on repair pathway usage may be more important than energetic costs. We also show that the repair differences between high- and low-condition flies resemble those between young and old flies, suggesting the underlying mechanisms may be similar. Finally, we observe that the effect of larval diet on adult repair increases as flies age, indicating that developmental differences early in life can have long-lasting consequences.
Apparatus and methods employed in the X-ray examination of cement compounds at Birkbeck College Research Laboratories
Authors: Jeffery J. W.
Published: July 2012

Summary:

The scope of the work being undertaken in the Cement Section of Birkbeck College Research Laboratories is outlined. A brief account of the phenomena of X-ray reflection from crystals is followed by a description of: (a) X-ray tubes, H. T. gear and general layout of the laboratory: (b) powder cameras and accessories, and powder photographs; (c) single crystal cameras and photographs; (d) a special camera for long range work; (e) photographs taken of hydration products using a mica cell; (f) auxiliary apparatus. The article ends with an appeal for co-operation from users and manufacturers of cement to provide the crystal specimens necessary to carryon the work.
The strength of reinforced concrete beams in shear
Authors: Wilby C. B.
Published: July 2012

Summary

This paper deals mainly with the effect of the following factors upon the ultimate shearing strengths of beams:—

(i) The percentage and spacing of the web reinforcement for stirrups inclined at 45° to the horizontal.

(ii) The ratio of span under shear to the eflective depth for beams with plain webs and for two series of beams with different web ratios.

(iii) The percentages of longitudinal compression and tension reinforcement for beams with plain webs and for two series of beams with different web ratios.

In the beams with reinforced webs the stirrups were inclined at 45° to the horizontal, and a total of 79 shear failures was investigated from a study of asymmetrically reinforced beams and eccentrically loaded beams.

The basic assumptions of the various theories in existence were investigated by numerous measurements of concrete and steel strains, defiexions, and widths of cracks.

The results are discussed with regard to existing theories and past research work. It is shown that even small percentages of web reinforcement, below the percentage permitted by the British Code of Practice, were effective in increasing the ultimate shearing failing load. The yield stress of the stirrup was never exceeded and the internal and external shearing forces can only be balanced by assuming that the beam behaves like an open-frame girder. The many theories are compared with the actual failing loads in shear and it is seen that the present British Code of Practice greatly unde~estimates the shearing strength of beams.
Vibrated concrete and mortar cubes: distribution of compressive strength
Authors: Williams T. E. H.
Published: July 2012

Summary:

This paper studies the variation in compressive strength of vibrated mortar cubes and vibrated concrete cubes. Within each of the four series of tests (two mortar and two concrete) the water-cement ratio was constant, but varied from series to series. The effect on compressive strength of varying the grading of the fine aggregate in concrete was observed. The mixes (including water-cement ratio) in the two mortar series were identical, but in one series (M.1) the mortar was vibrated to complete compaction by an electro-magnetic vibrator and in the other mortar series (M.2) a vibrator of the type described in BS 12(1947) was used for the specified time of 2 minutes for each cube.

The coefficient of variation of concrete strength was found to be less than 4 per cent and that of mortar strength to be more than 5 per cent.

It was determined that wide variations in fine aggregate grading had no effect on the dispersion of the values of the compressive strength of concrete. The two methods of compaction used for mortar cubes resulted in widely different mean compressive strengths but the coefficients of variation obtained/or the two series were similar.
Discontinuity in prestressed concrete pipes
Authors: Ooykaas G. A. P.
Published: July 2012

Summary:

The paper gives an analysis of the stresses which may act at the extremities of prestressed concrete pipes, where the prestressed pipe wall changes into the non-prestressed ends.
The Swedish Cement and Concrete Research Institute
Authors: Andrew Ralph P.
Published: July 2012

Summary

The paper gives a description of the laboratories of the Swedish Cement and Concrete Research Institute in Stockholm, which were opened in 1945.

A short note on the research problems at present under investigation is included.
Model tests on a thin prestressed barrel roof
Authors: Vlachlis D.
Published: July 2012

Summary

In order to assist consideration of the design and development of large span prestressed concrete shell roofs a model was constructed and subjected to a series of tests.
An experiment on the theory of voids in granular materials
Authors: Worthington P. M.
Published: July 2012

Summary

The purpose of this experiment was to study the way in which the voids ratio of a granular material depends upon the grading, and in particular to find the grading curve which gives the minimum voids ratio. The theoretical approach is discussed, but as it is not amenable to a complete study of the problem a carefully controlled experiment was carried out. The applications are not discussed in this paper but the most useful application is in the design of concrete mixes.
The design of prestressed continuous beams of uniform section
Authors: Robertson R. G.
Published: July 2012

Summary

The economy of continuous prestressed beams is investigated, with particular reference to three-span beams. Maximum moment envelopes and maximum moment coefficients for three-span beams of several span ratios are given, and compared to those for simply supported spans.

At the critical section prestressing may be arranged to neutralize the mean moment, so that the maximum stresses are equalized in top and bottom fibres; this results in an equation giving the beam dimensions in terms of the range of moment.

At other sections the stresses are smaller, and the position of the cable may be adjusted so as to eliminate secondary moments; the required cable profile depends on the span ratios and the loading, and a method of determining a suitable profile is described.

Precast beams erected as simple spans and subsequently made continuous are shown to be less economical in material than cast in situ continuous beams when the preliminary cables required for the erection of the precast spans are left in place; haunched beams are shown to be less economical than beams of uniform section when live load predominates. Three examples illustrate the calculations for the three types of construction.
The effect of grading and shape on the bulk density of concrete aggregates
Authors: Moncrieff D. S.
Published: July 2012

Summary

Laboratory tests have shown that variation of grading within the limits permitted by the British Standard 882:1944 for concrete aggregates results in differences of as much as 12 lb/cu.ft. in the compacted bulk density of coarse aggregates, and 13 lb/cu.ft. in Class A and 31 lb/cu.ft. in Class B fine aggregates. It was also found that the bulk densities of different gradings of a rounded aggregate were between 5 and 10 per cent higher than those of the corresponding gradings of an angular aggregate with the same specific gravity.
Foundations for concrete roads: their preparation and protection
Authors: Maclean D. J.
Published: July 2012

Summary

This paper describes the practical measures that should be adopted by road engineers in the initial preparation and for the subsequent protection of the foundations of concrete roads.

The provision of a stable foundation for a concrete road consists of: (1) the selection of suitable soils for embankments and materials for the road bases; (2) the compaction of these soils and materials; (3) the control of the moisture conditions in these soils and materials.

Each of these aspects is dealt with in turn, and the paper concludes with a selection of photographs of concrete roads which illustrate a number of cases in which defects might have been avoided if more attention had been given in the first place to the provision of a stable foundation.
Effect on reinforcement in concrete of calcium chloride used as an admixture
Authors: Muller P. P.
Published: July 2012

Summary

This paper gives a brief account of some long-term tests which were undertaken to determine the possible adverse effects of the use of calcium chloride as an admixture upon the reinforcement of concrete. It was found that, even after more than six years, there was no sign of corrosion attributable to the use of calcium chloride.
The distribution of a load in a box-section bridge from tests on a Xylonite model
Authors: Little G.
Published: July 2012

Summary

A small model of a box beam bridge was tested for its load distribution properties. The distribution was determined experimentally by deflexion and strain readings.

The material used in the construction of the model was Xylonite, a cellulose-base material of Young's modulus 33·33 × 104 lb/sq.in. and modulus of rigidity 11·7 × 104 lb/sq.in.

The experimental distribution of deflexions and longitudinal bending moments proved to be in close agreement with the distribution given by a theoretical treatment involving distribUlion factors. The distribution patterns were found to be virtually unaffected by changes in the longitudinal position of the load.

On the other hand, there were large discrepancies between the experimental and theoretical transverse bending moments. The discrepancies were almost certainly due in part to the small absolute values of the bending moments, which were only about 40 per cent of the corresponding longitudinal moments, and to their high rate of variation across the transverse section both in magnitude and sense. Nevertheless, it was confirmed that the maximum transverse moment occurs at the centre of the bridge when the load is at its position of minimum eccentricity. Further investigation into the distribution of transverse moments will be made on suitably designed models.
An experimental investigation of the influence of the formation of a plastic hinge on the shear strength of a singly reinforced concrete beam
Authors: Khan N. M. , Mattock A. H.
Published: July 2012

Summary

A series of rectangular reinforced concrete beams was tested in such a way as to simulate the conditions at a plastic hinge over a support of a continuous beam approaching failure. With the plastic hinge moment constant, the shear force on the section was increased until failure occurred in shear. Similar sections were tested in shear in an uncracked state.

The results indicate that the presence of a plastic hinge does not reduce the ultimate shear strength of a reinforced concrete section.
A method for the calculation of the specific gravities of calcium silicates from their refractive indices
Authors: Howison J. W. , Taylor H. F. W.
Published: July 2012

Summary

A method is described for the calculation of the specific gravity of any anhydrous or hydrated calcium silicate from its mean refractive index. The results usually agree to within ±2% with those determined directly by the suspension or pycnometer methods.
The use of fly ash in soil stabilization
Authors: Wright W. , Ray P. N.
Published: July 2012

Summary

An increasing quantity of fly ash is being produced by the power stations of this country. Experiments using three different soils are described which suggest that fly ash can replace some of the cement normally used for soil stabilization.
Automatic control and recording of load during relaxation tests on prestressing wires
Authors: Bannister J. L. , Butler L. H.
Published: July 2012

Summary

A simple unit has been incorporated in a universal testing machine to compensate automatically for the continuously reducing load during relaxation tests on prestressing wires. In conjunction with a recording camera, it dispenses with the presence of an observer over the long periods required for the tests. In operation it is found that alternate readings taken with automatic and manual control fall sensibly on a single curve.
The strength of right prestressed concrete slab bridges with edge beams
Authors: Reynolds G. C.
Published: July 2012

Summary

Two small prestressed concrete slab bridges with edge beams have been tested to failure under single concentrated loads, and the results are in close agreement with those predicted by the yield line method of analysis.
Load distribution in bridge slabs (with special reference to transverse bending moments determined from tests on three prestressed concrete slabs)
Authors: Rowe R. E.
Published: July 2012

Summary

Tests on three prestressed concrete slabs of varying span/breadth ratios have given data concerning the load distribution properties of such structural forms.

The results for the distribution of deflexions and longitudinal and transverse bending moments under one, two and four equal loads are given and compared with results given by the theoretical analysis. The effect of considering Poisson's ratio in the theoretical analysis is discussed.

The distribution of the transverse bending moments, both in the transverse and longitudinal directions, is considered in detail. The maximum value of the transverse moment occurring under the Ministry of Transport abnormal load is esdmated and the position of the wheel loads to give the maximum moment is considered. The variation in the transverse moments along the span due to such abnormal loading is also discussed.
Quality control in prestressed concrete production
Authors: Masterman O. J.
Published: July 2012

Summary

This paper outlines a system of quality control applied to prestressed concrete joists in which the control depends upon daily testing of a random. selection of the actual joists. The non-destructive testing includes obtaining the modulus of elasticity of the concrete and the load at the first crack for each joist; corresponding cubes are made for crushing at 1 and 28 days. Results are analysed and the means and standard deviations recorded.
The effect of creep upon redundant reactions in continuous prestressed concrete beams
Authors: Saeed-ud-din K. , Hall A. S.
Published: July 2012

Summary

The redundant reactions induced in a statically indeterminate prestressed structure by the use of a non-concordant tendon diminish as the prestressing force decreases with time. This effect is not investigated.

The possibility exists that the redundant reactions may decrease independently of variation in cable force. A theory is advanced in which the variation of the reactions is expressed in terms of the phenomena of creep at constant stress and stress relaxation at constant strain.

Using previous data and suggested relations between these phenomena, it is predicted that, for beams constructed in the normal way, these effects cancel one another.

Tests on two-span beams support the predicted variation of reaction, and thus tend to confirm the assumed relation between creep and stress relaxation.
An analysis of deformation and failure characteristics of concrete
Authors: Baker A. L. L.
Published: July 2012

Summary

The paper shows that the aggregate grading and compaction required for strong concrete produce an internal structural system which approximates to a series of lattices in two directions at right-angles. The diagonal members of the lattice are stiffer than the cross members, which represent the mortar in the “voids”, bonded to the diagonal members. The idealized system is analysed in terms of the relative stiffness of the lattice members, and equations are derived and curves plotted from which Poisson's ratio is related to stiffness ratios for various values of the ratio of axial compression to transverse tensile strength. The curves give a reasonable explanation of changes in Poisson's ratio and compressive strength due to changes in the secant elastic modulus of mortar due to creep.

The paper also introduces a useful model technique by which the internal structural system of concrete can be represented. Ordinary draper's elastic is used to form a lattice having members of appropriate relative stiffness. The elastic is prestressed to prevent buckling. External compression acting on concrete specimens may be studied as external tension on the model, since changes of internal stresses and strains are sufficient to indicate internal distribution. Such models may be used to obtain the distribution of maximum tensile stresses in a concrete specimen under test, and hence the crack pattern and mode of failure for various shapes and external restraints.
The effect of water absorption by aggregates on the water/cement ratio of concrete
Authors: Newman K.
Published: July 2012

Summary

Tests were made on damp and dry aggregates to discover how the definition of “effective water/cement ratio” is affected by aggregate absorption. Analysis of the results indicates that mixes with saturated river gravel aggregates give higher strengths and compacting factors than supposedly similar mixes made with dry aggregates. The coating of cement paste considerably reduces the rate of absorption, which ceases when the paste hardens.

The effective water/cement ratio for strength should be based on the free water content available when the paste hardens. This is known more accurately when saturated aggregates are used. For dry aggregates, crushed rock material becomes saturated to the same degree as after immersion in water for 30 min, but for uncrushed river gravels the degree of saturation depends on the amount and consistence of the cement paste.

The effective water/cement ratio for workability is more difficult to define. It can be assumed, provisionally, that initially dry aggregates will have achieved, at the time of the workability test, the same degree of saturation as they would have in water.

These effects of absorption only apply to high-strength mixes. Rich, uneconomical site mixes can be avoided if laboratory trials are based on the effective water/cement ratio as defined in this paper.
Hydrothermal reactions in the lime-rich part of the system CaO-SiO2-H2O
Authors: Midgley H. G. , Chopra S. K.
Published: July 2012

Summary

The mineralogy of autoclaved products from various forms of calcium silicate andfrom lime and silica has been investigated. The results are as follows. With a CaO/SiO2 ratio of 1, the product is always well crystallized tobermorite. With a CaO/SiO2 ratio of 2, the product varies: starting with lime and silica, dicalcium silicate alpha-hydrate is the first product; this eventually changes into dicalcium silicate beta-hydrate, the stable phase; starting with calcium silicate hydrate I and lime, the first product comprises Flint's CSH(A) and dicalcium silicate alpha-hydrate, and it seems likely that the Flint's CSH(A) will eventually convert to dicalcium silicate alpha-hydrate and the dicalcium silicate alpha-hydrate to dicalcium silicate beta-hydrate; if one starts with β-2CaO.SiO2, the product in the first place is dicalcium silicate gamma-hydrate; in the length of processing used in the experiments reported in this paper, no other phase was found, but it is considered that dicalcium silicate gamma-hydrate is only metastable.

With a CaO/SiO2 ratio of 3, again the products vary with the starting minerals: with mixes of lime and silica and with mixes of 2CaO.SiO2 and lime, the first product is dicalcium silicate alpha-hydrate which is eventually converted to the beta-hydrate; with mixes of calcium silicate hydrate (1) and lime, the product is always Flint's CSH(A) with or without some dicalcium silicate alpha-hydrate; with 3CaO.SiO2 as the starting material, the product is always 3CaO.SiO2.1½H2O.

It is clear from this work that the form of the starting material has a considerable influence on the nature of the metastable phases produced, and also that, in this part of the system CaO-SiO2-H2O, even prolonged processing up to 90 days is insufficient to produce true equilibrium phases.
Some tests on beams prestressed by fibre-glass cords
Authors: Kajfasz Stanislaw
Published: July 2012

Summary

The paper discusses tests on 12 concrete beams prestressed by fibre-glass cords. The values of the forces in the cables are calculated on the basis of the test results. The influence of bond between tendons and concrete on the behaviour of beams is investigated. The low value of modulus of elasticity offibre-glass tendons is discussed.

The results obtained on beams with fibre-glass reinforcement are compared with the results obtained on 23 similar beams prestressed with steel wires.
The design of biaxially loaded columns by ultimate load methods
Authors: Pannell F. N.
Published: July 2012

Summary

The paper describes a method of defining the curves relating ultimate load and moment for rectangular columns having an equal area of steel in each face, and subjected to any radial eccentricity of loading. This leads to a method of accurate and rapid design.

The validity of the approach is demonstrated by case analysis.
Some shear tests on reinforced concrete beams without shear reinforcement
Authors: Taylor R.
Published: July 2012

Summary

Tests were made on rectangular reinforced concrete beams without shear reinforcement in order to determine the effect on shear strength of: manner and position of loading; amount and type of reinforcement; strength of concrete. The results indicate that:

for short shear spans, a beam loaded directly on its top surface can sustain a load greater than that causing the formation of a major inclined crack (the diagonal cracking load), but only with considerable widening of the crack;

a beam loaded through transverse beams or nibs will not sustain a load higher than the diagonal cracking load, whatever the shear span;

the diagonal cracking load increases slightly with increase in the amount of longitudinal reinforcement, but is apparently little affected by the bond characteristics of the bars;

the diagonal cracking load increases with increase in the strength of the concrete, but not at the rate indicated by the British Standard Code of Practice CP 114:1957.

In an evaluation of the results of the tests a method is developed for estimating the diagonal cracking load of rectangular beams without shear reinforcement. From a comparison with available test data it is shown that, though the method is simple in its application, it has a fair degree of accuracy. Design recommendations based on it are given.
Concrete under triaxial stress
Authors: Akroyd T. N. W.
Published: July 2012

Summary

This paper describes the results of the first series of experiments carried out to study the effect of pore-water pressure on the ultimate strength of concrete subject to triaxial stresses. These tests have demonstrated that saturated concrete behaves like a material which does not possess the property of internal friction, when tested triaxially under conditions of no change of water content (undrained test).
The effects of thermal incompatibility and shrinkage on the strength of concrete
Authors: Dougill J. W.
Published: July 2012

Summary

The effect of shrinkage of the mortar on the strength of a concrete specimen is demonstrated by means of a lattice analogy for concrete. The strains due to the thermal incomptability of the cement paste and the aggregate in a concrete heated to high temperatures are taken as a particular example and it is shown that the results deduced from the lattice agree closely with those obtained experimentally by other workers.

The limitations of the lattice approach are discussed: it is emphasized that the method is qualitative and that any extension to give quantitative results would be most unlikely to be successful.
Reinforced concrete under thermal gradients
Authors: England G. L. , Ross A. D.
Published: July 2012

Summary

The significance and current knowledge of thermal effects in concrete and reinforced concrete are reviewed briefly. It is evident that there is a need for more basic data on the shrinkage and creep of concrete subjected to high temperatures. Tests designed to obtain some of these data are described; results for the shrinkage and creep of a particular concrete at temperatures up to l40°C are presented. Some of the specimens were sealed to prevent loss of moisture, to simulate the conditions in mass concrete. It is shown that the time-dependent strains are markedly temperature-dependent.

The paper then describes tests on model reinforced concrete beams subjected to a thermal gradient while flexurally restrained but without longitudinal restraint. The behaviour of the unsealed beams showed a severe departure from the predictions of conventional elastic theory, even to the extent of indicating compression in the reinforcing steel, instead of the expected tension. This was due to shrinkage and creep under the high temperatures. The behaviour of the sealed reinforced concrete specimens approximated to the predictions of elastic theory with a low value of the elastic modulus.

A numerical procedure for estimating approximately the effects of time- and temperature-dependent strains in flexurally restrained beams is outlined in an Appendix.
Strain measurements on reinforced concrete columns
Authors: Ashworth R.
Published: July 2012

Summary

The change of strain in members of a reinforced concrete structure has been traced during and after construction over a period of three years using vibrating-wire strain gauges attached to the reinforcing bars and by making supplementary surface strain measurements with a Demec gauge. Total strains of the order of – 900 × 10−6 were recorded, with average steel stresses in one column of 27,400 lb/in2. The average concrete stress is estimated to have been 600 lb/in2. Short-term tests were also carried out to study the behaviour of the members under known loading conditions, and electrical resistance strain gauges attached to the reinforcing bars were used in addition to the vibrating-wire gauges. The performance of both types of embedded gauge is discussed and attention is drawn tofactors which curtailed the effective life of a number of vibrating-wire gauges.
The behaviour of prestressed concrete sections near the maximum moment
Authors: la Grange L.
Published: July 2012

Summary

Tests are described in which prestressed concrete sections were tested in pure bending in such a way that the complete moment-curvature curves could be obtained. The special requirements of the testing equipment are discussed and it is shown that there are descending branches to the moment-curvature curves of both underand over-reinforced sections. A theoretical discussion is given of the conditions of maximum moment of underand over-reinforced sections, including the cases of combinations of bending moment and axia load. The analysis is based on the stress-strain curve of concrete and it is shown that the conventional curves are not the true stress-strain curves of concrete. Attempts to obtain the actual curves are described; the parameters thus obtained are used in the analysis and give close agreement with measurements of maximum bending moments and curvatures in actual tests.
The effect on normal ⅜ in. reinforcement of adding calcium chloride to dense and porous concretes
Authors: Blenkinsop J. C.
Published: July 2012

Summary

This paper deals with a five-year investigation into the corrosion of mild steel reinforcement embedded at various depths in dense and porous concretes containing calcium chloride. Half the number of specimens were exposed to the effects of the weather on the exposure site at the Building Research Station and the remainder were half-immersed in water in the laboratory; control tests were also made with dense and porous concretes containing no calcium chloride.

After five years it was found that 2% of flake calcium chloride by weight of cement added to concrete had little or no effect on the reinforcement embedded in dense concrete when the cover was at least ½ in. With porous concretes stored outside, however, there was considerably more corrosion of the bars taken from concrete containing calcium chloride than from the control concrete and some corrosion was seen even with 1½ in. cover. In no case could the corrosion be said to have reached serious proportions for reinforcement of ⅜ in. diameter or more but similar amounts of corrosion on thinner bars would probably have caused a serious reduction in the cross-section of the bar, with consequent loss of strength of any reinforced concrete unit.
Young's modulus and Poisson's ratio of concrete cured at various humidities
Authors: Plowman J. M.
Published: July 2012

Summary

Tests are described designed to determine values of E and σ for concretes of various mix proportions and water/cement ratios. The influence of age (maturity) and humidity of curing have also been investigated.
Strain measurements on saturated concrete specimens
Authors: Newman K. , Lachance L. , Loveday R. W.
Published: July 2012

Summary

A programme of work on the mode of deformation and failure of plain concrete has called for the measurement of local tensile strains on the surface and the over-all deformation of saturated, as well as dry, concrete test specimens. Two different strain-measuring techniques have been developed to give this information. In the first, electrical resistance strain gauges, suitably protected, are attached to the mould and cast in situ. These local in-surface gauges are located just beneath the plane of the surface of the specimen. In the second technique, detachable gauges of any length and suitable for measuring over-all strains are manufactured by attaching electrical resistance strain gauges to Perspex strips or rings. Details are given of the methods of manufacture and use of the gauges and comparisons are made between the strains measured with the in-surface and on-surface foil gauges and roller extensometers. The different values obtained imply that the gauges and extensometers are measuring basically different properties of a deformed concrete specimen, and when absolute strain measurements are required this should be recognized.
Creep of concrete as a function of its cement paste content
Authors: Neville A. M.
Published: July 2012

Summary

It is shown that for specimens subjected to a sustained load at a constant stress/strength ratio there is a simple relation between creep and the amount of cement paste in the concrete. The cement content affects also the rate of creep, leaner mixes achieving a given proportion of their long-term creep earlier than rich mixes. This behaviour is shown to be related to the rate of increase in strength ofthe specimen while under load, and is verified for ordinary and rapid-hardening Portland cements. The prediction of creep from the relations established is discussed.
The effect of various heat treatments of the clinker on the early hydration of cement pastes
Authors: Chatterji S. , Jeffery J. W.
Published: July 2012

Summary

Three commercial Portland cement clinkers (low-heat, ordinary and sulphate-resisting) were each given three different heat treatments. The hydration reactions of cements made of these clinkers were then observed by electron-optical and X-ray diffraction techniques from 4 min to 3 months. It has been found that alumina- and iron-bearing compounds in commercial clinkers have reactivities different from those of laboratory-made C3A and C4AF. Alumina- and iron-bearing compounds in commercial clinkers can be made to approach the reactivity of pure C3A and C4AF by prolonged annealing at 1,280°C. Direct evidence of “through-solution” conversion of C4AHx to ettringite has been found.
The effective width of T beams
Authors: Severn R. T.
Published: July 2012

Summary

A method is described for the accurate determination of effective widths of isolated T beams and of T and L beams which form part of a larger structure. This method takes into account the bending stiffness of the flanges in a more satisfactory way than has been used hitherto. Some Tables of effective widths have been calculated for various loading conditions and variations in the geometry of the beams, and comparison is made, where possible, with values produced by the Comite Europeen du Bit on.
Concrete reinforced with glass fibres
Authors: Agbim C. C.
Published: July 2012

Summary

The paper is a summary of test results on the utilization of tensile strength of glass fibres for the reinforcement of concrete members. Particular reference is made to shell structures, and the paper includes the results of preliminary investigations carried out on simpler structures, aimed at obtaining exploratory information on the behaviour of composites of concrete and glass fibre.
A note on the occurrence of crystals of calcium hydroxide and ettringite in voids in hardened Portland cement paste
Authors: Gillott J. E. , Ritchie T.
Published: July 2012

Summary

The occurrence of crystals of calcium hydroxide and of ettringite (calcium sulphoaluminate) in hardened Portland cement, reported previously by others, is confirmed. Samples of hardened Portland cement paste prepared half a century ago at one of Canada's earliest cement plants were, on examination, found to contain voids in which well developed crystals had formed. The crystals occurred as thin plates and needles that were identified by optical microscopy and X-ray diffraction as calcium hydroxide and ettringite, respectively. It is of interest that the calcium hydroxide had not been altered to carbonate even though the cement samples had been stored for a long time under conditions that would be expected to promote this change.