bluuebunny/crossref_metadata_2025 huggingface dataset:
Teaching the Rational Use of Medicinesto medical students: a qualitative research
Authors: Patrício Karina Pavão , Alves Nycholas Adriano Borges , Arenales Nadja Guazzi , Queluz Thais Thomaz
Published: July 2012

Background

Prescribing is a complex and challenging task that must be part of a logical deductive process based on accurate and objective information and not an automated action, without critical thinking or a response to commercial pressure. The objectives of this study were 1) develop and implement a discipline based on the WHO’s Guide to Good Prescribing; 2) evaluate the course acceptance by students; 3) assess the impact that the Rational Use of Medicines (RUM) knowledge had on the students habits of prescribing medication in the University Hospital.

Methods

In 2003, the RUM principal, based in the WHO's Guide to Good Prescribing, was included in the official curriculum of the Botucatu School of Medicine, Brazil, to be taught over a total of 24 hours to students in the 4th year. We analyzed the students' feedback forms about content and teaching methodology filled out immediately after the end of the discipline from 2003 to 2010. In 2010, the use of RUM by past students in their medical practice was assessed through a qualitative approach by a questionnaire with closed-ended rank scaling questions distributed at random and a single semistructured interview for content analysis.

Results

The discipline teaches future prescribers to use a logical deductive process, based on accurate and objective information, to adopt strict criteria (efficacy, safety, convenience and cost) on selecting drugs and to write a complete prescription. At the end of it, most students considered the discipline very good due to the opportunity to reflect on different actions involved in the prescribing process and liked the teaching methodology. However, former students report that although they are aware of the RUM concepts they cannot regularly use this knowledge in their daily practice because they are not stimulated or even allowed to do so by neither older residents nor senior medical staff.

Conclusions

This discipline is useful to teach RUM to medical students who become aware of the importance of this subject, but the assimilation of the RUM principles in the institution seems to be a long-term process which requires the involvement of a greater number of the academic members.
Cytotoxicity and radiosensitising activity of synthesized dinitrophenyl derivatives of 5-fluorouracil
Authors: Abdi Khosrou , Khalaj Ali , Ostad Syeed-Naser , Khoshayand Mohammad Reza
Published: July 2012

Background and the purpose of the study

Dual functional agents in which nitroaromatic or nitroheterocyclic compounds are attached through a linker unit to mustards and aziridines have shown higher cytotoxicities than the corresponding counterparts to both aerobic and hypoxic cells and enhanced radiosensitizing activity. In the present investigation cytotoxicity and radiosensitizing activity of 2,4-dinitrobenzyl, 2,4-dinitrobenzoyl, and 2,4-dinitrophenacetyl derivatives of 5-fluorouracil which was assumed to release cytotoxic active quinone methidide and 5-fluorouracil under hypoxic conditions on HT-29 cell line under both aerobic and hypoxic conditions was investigated.

Methods

5-fluorouracil derivative X-XIII were prepared by the reaction of the corresponding di-nitro substituted benzyl, benzoyl and phenacetyl halides with 5-fluorouracil protected at N-1 with di-t-butoxydicarbonate (BOC) in dimethyl formamide (DMF) in the presence of the potassium carbonate followed by hydrolysis of the blocking group by potassium carbonate in methanol. Cytotoxicity of fluorouracil VIII and tested compounds X-XIII against HT-29 cell line under both aerobic and hypoxic conditions after 48 hrs incubation were measured by determination of the percent of the survival cells using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and percent of the dead cells using propidium iodide(PI)-digitonine assay and results were used to calculate the corresponding IC50 values. Radiosensitization experiments were carried out by irradiation of the incubations with a 60Co source and clonogenic assay was performed to determine the cell viabilities following treatment with the tested compounds and/or radiation. Sensitization Enhancement Ratio (SER) of each tested compound was obtained from the radiation survival curves in the absence and presence of each sensitizer for 37% survival respectively.

Results and major conclusion

Findings of the present study showed that alkylation or acylation of 5-fluorouracil result in compounds which have little or no cytotoxicity and radiosensitizing activity under aerobic conditions, but have high cytotoxicity and radiosensitizing effects under hypoxic conditions. Furthermore radiosensitizing activities of compounds under hypoxic conditions increased by increase in their concentrations and SER of the tested 5-FU derivatives at concentrations higher than 50 μmol were equal or higher than 1.6 which is the minimum effective SER of a radiosensitizer in an in vitro assay.
Common fixed points of g-quasicontractions and related mappings in 0-complete partial metric spaces
Authors: di Bari Cristina , Kadelburg Zoran , Nashine Hemant Kumar , Radenović Stojan
Published: July 2012

Common fixed point results are obtained in 0-complete partial metric spaces under various contractive conditions, including g-quasicontractions and mappings with a contractive iterate. In this way, several results obtained recently are generalized. Examples are provided when these results can be applied and neither corresponding metric results nor the results with the standard completeness assumption of the underlying partial metric space can.

MSC:47H10, 54H25.
Detection method of flexion relaxation phenomenon based on wavelets for patients with low back pain
Authors: Nougarou François , Massicotte Daniel , Descarreaux Martin
Published: July 2012

The flexion relaxation phenomenon (FRP) can be defined as a reduction or silence of myoelectric activity of the lumbar erector spinae muscle during full trunk flexion. It is typically absent in patients with chronic low back pain (LBP). Before any broad clinical utilization of this neuromuscular response can be made, effective, standardized, and accurate methods of identifying FRP limits are needed. However, this phenomenon is clearly more difficult to detect for LBP patients than for healthy patients. The main goal of this study is to develop an automated method based on wavelet transformation that would improve time point limits detection of surface electromyography signals of the FRP in case of LBP patients. Conventional visual identification and proposed automated methods of time point limits detection of relaxation phase were compared on experimental data using criteria of accuracy and repeatability based on physiological properties. The evaluation demonstrates that the use of wavelet transform (WT) yields better results than methods without wavelet decomposition. Furthermore, methods based on wavelet per packet transform are more effective than algorithms employing discrete WT. Compared to visual detection, in addition to demonstrating an obvious saving of time, the use of wavelet per packet transform improves the accuracy and repeatability in the detection of the FRP limits. These results clearly highlight the value of the proposed technique in identifying onset and offset of the flexion relaxation response in LBP subjects.
Vasculitic emergencies in the intensive care unit: a special focus on cryoglobulinemic vasculitis
Authors: Zaidan Mohamad , Mariotte Eric , Galicier Lionel , Arnulf Bertrand , Meignin Véronique , Vérine Jérôme , Mahr Alfred , Azoulay Élie
Published: July 2012

Vasculitis is characterized by the infiltration of vessel walls by inflammatory leukocytes with reactive damage and subsequent loss of vessel integrity. The clinical course of systemic vasculitis may be punctuated by acute life-threatening manifestations that require intensive care unit (ICU) admission. Furthermore, the diagnosis may be established in the ICU after admission for a severe inaugural symptom, mostly acute respiratory failure. Among the systemic vasculitides, cryoglobulinemic vasculitis (CV) has been rarely studied in an ICU setting. Severe CV-related complications may involve the kidneys, lungs, heart, gut, and/or central nervous system. The diagnosis of CV in the ICU may be delayed or completely unrecognized. A high level of suspicion is critical to obtain a timely and accurate diagnosis and to initiate appropriate treatment. We describe severe acute manifestations of CV based on six selected patients admitted to our ICU. That all six patients survived suggests the benefit of prompt ICU admission of patients with severe CV.
Low Rates of Hepatitis B Virus Screening at the Onset of Chemotherapy
Authors: Hwang Jessica P. , Fisch Michael J. , Zhang Hong , Kallen Michael A. , Routbort Mark J. , Lal Lincy S. , Vierling John M. , Suarez-Almazor Maria E.
Published: July 2012

Future research directed toward identifying best screening methods and HBV risk tools will be necessary to reduce the risk of reactivation of HBV infection after chemotherapy.
The Rising Cost of Cancer Care: Physicians Take Charge
Authors: Schnipper Lowell E.
Published: July 2012

The author comments on the ASCO Top Five, a list of five commonly utilized practices in each oncology specialty for which there is no evidence to support their use.
Exposure to critical thermal maxima causes oxidative stress in hearts of white- but not red-blooded Antarctic notothenioid fishes
Authors: Mueller Irina A. , Devor Devin P. , Grim Jeffrey M. , Beers Jody M. , Crockett Elizabeth L. , O'Brien Kristin M.
Published: July 2012

Antarctic icefishes have a significantly lower critical thermal maximum (CTmax) compared to most red-blooded notothenioid fishes. We hypothesized that the lower thermal tolerance of icefishes compared to red-blooded notothenioids may stem from a greater vulnerability to oxidative stress as temperature increases. Oxidative muscles of icefishes have high volume densities of mitochondria, rich in polyunsaturated fatty acids, which can promote the production of reactive oxygen species (ROS). Moreover, icefishes have lower levels of antioxidants compared to red-blooded species. To test our hypothesis, we measured levels of oxidized proteins and lipids, and transcript levels and maximal activities of antioxidants in heart ventricle and oxidative pectoral adductor muscle of icefishes and red-blooded notothenioids held at 0°C and exposed to their CTmax. Levels of oxidized proteins and lipids increased in heart ventricle of some icefishes but not in red-blooded species in response to warming, and not in pectoral adductor muscle of any species. Thus, increases in oxidative damage in heart ventricles may contribute to the reduced thermal tolerance of icefishes. Despite an increase in oxidative damage in hearts of icefishes, neither transcript levels nor activities of antioxidants increased, nor did they increase in any tissue of any species in response to exposure to CTmax. Rather, transcript levels of the enzyme superoxide dismutase (SOD) decreased in hearts of icefishes and the activity of SOD decreased in hearts of the red-blooded species Gobionotothen gibberifrons. These data suggest that notothenioids may have lost the ability to elevate levels of antioxidants in response to heat stress.
Light-induced degeneration and microglial response in the retina of an epibenthonic pigmented teleost: age-dependent photoreceptor susceptibility to cell death
Authors: Bejarano-Escobar Ruth , Blasco Manuel , Martín-Partido Gervasio , Francisco-Morcillo Javier
Published: July 2012

Constant intense light causes apoptosis of photoreceptors in the retina of albino fish. However, very few studies have been performed on pigmented species. Tench (Tinca tinca, Linnaeus 1758) is a teleost inhabiting dimly lit environments with predominance of rods within the photoreceptor layer. To test the hypothesis that constant high intensity light can result in retinal damage in such pigmented epibenthonic teleost species, photodegeneration of the retina was investigated in the larvae and in juveniles of tench to assess whether any damage may also be dependent on fish age. We exposed both groups of animals to 5 days of constant darkness, followed by 4 days of constant 20000 lux light, and then by 6 days of recovery in a 14 h light: 10 h dark cycle. The results showed that the retina of the larvae group exhibited abundant photoreceptor cell apoptosis during the time of exposition to intense light, whereas that of juveniles was indifferent to it. Damaged retinas showed a strong TUNEL signal in photoreceptor nuclei, and occasionally a weak cytoplasmic TUNEL signal in Müller glia. Specific labeling of microglial cells with Griffonia simplicifolia lectin (GSL) histochemistry revealed that photoreceptor cell death alerts microglia in the degenerating retina, leading to local proliferation, migration towards the injured outer nuclear layer (ONL), and enhanced phagocytosis of photoreceptor debris. During the first days of intense light treatment, Müller cells phagocytosed dead photoreceptor cells, but, once microglial cells became activated, there was a progressive increase in the phagocytic capacity of the microglia.
Intense flight and endotoxin injection elicit similar effects on leukocyte distributions but dissimilar effects on plasma-based immunological indices in pigeons
Authors: Matson Kevin D. , Horrocks Nicholas P. C. , Tieleman B. Irene , Haase Eberhard
Published: July 2012

Most birds rely on flight for survival. Yet as an energetically-taxing and physiologically-integrative process, flight has many repercussions. Studying pigeons (Columba livia) and employing physiological and immunological indices that are relevant to ecologists working with wild birds, we determined what, if any, acute immune-like responses result from bouts of intense, non-migratory flight. We compared the effects of flight with the effects of a simulated bacterial infection. We also investigated indices in terms of their post-flight changes within individuals and their relationship with flight speed among individuals. Compared to un-flown controls, flown birds exhibited significant elevations in numbers of heterophils relative to numbers of lymphocytes and significant reductions in numbers eosinophils and monocytes. Furthermore, within-individual changes in concentrations of an acute phase protein were greater in flown birds than in controls. However, none of the flight-affected indices showed any evidence of being related to flight speed. While some of the effects of flight were comparable to the effects of the simulated bacterial infection, other effects were observed only after one of these two physiological challenges. Our study suggests that flight by pigeons yields immune-like responses, and these responses have the potential to complicate the conclusions drawn by ecologists regarding immune function in free-living birds. Still, a better understanding of the repercussions of flight can help clarify the ties between the physiology of exercise and the disease ecology of migration and will ultimately assist in the broader goal of accounting for immunological variation within and among species.
Ovary ecdysteroidogenic hormone activates egg maturation in the mosquito, Georgecraigius atropalpus, after adult eclosion or a blood meal
Authors: Gulia-Nuss Monika , Eum Jai-Hoon , Strand Michael R. , Brown Mark R.
Published: July 2012

The rockpool mosquito, Georgecraigius atropalpus, is a facultatively autogenous species that produces its first egg clutch without a blood meal shortly after emergence. Several days after depositing this clutch, females must take a blood meal to produce a second egg clutch. Decapitation of females shortly after emergence or blood ingestion prevents egg maturation. Here, we report that a single injected dose of the neuropeptide, ovary ecdysteroidogenic hormone (OEH), fully restored egg maturation in females in both circumstances. This neuropeptide and two insulin-like peptides (ILPs) are potent gonadotropins in the related yellow fever mosquito, Aedes aegypti. ILP3 was marginally restorative in decapitated Gc. atropalpus, and ILP4 had no effect. Egg maturation in non- and blood-fed Gc. atropalpus was dependent on the enzymatic mobilization of amino acids from stored protein or the blood meal for yolk protein (vitellogenin, VG) synthesis and uptake by oocytes. We further show that OEH stimulates serine protease activity in the fat body of newly eclosed females or in the midgut of blood fed ones, and ecdysteroid hormone production by the ovaries of both females. In contrast, only 20-hydroxyecdysone stimulated VG synthesis in the fat body of non- and blood fed females. Using RNA interference to knock down expression of the insulin receptor, we found that OEH still fully restored autogenous egg maturation. In total, our results identify OEH as a primary regulator of egg maturation in both autogenous and blood-fed Gc. atropalpus females and suggest the shift from blood meal dependent to blood meal independent release of OEH is a key factor in the evolution of autogeny in this species.
Minors and refusal of medical treatment: a critique of the law regarding the current lack of meaningful consent with regards to minors and recommendations for future change
Authors: O'Brien Sinead
Published: July 2012

The autonomous right of competent adults to decide what happens to their own body and the corresponding right to consent to or refuse medical treatment are cornerstones of modern health care. For minors the situation is not so clear cut. Since the well-known case of Gillick, mature children under the age of 16 can agree to proposed medical treatment. However, those under the age of 18 do not enjoy any corresponding right to refuse medical treatment. Can this separation of the right to agree to treatment and the right to refuse treatment for those under 18, regardless of capacity, be justified? This paper evaluates the key cases in this area of the law. Changes to the current law are then proposed which aim to make the law more consistent and reasonable.
Interobserver variation in parotid gland delineation: a study of its impact on intensity-modulated radiotherapy solutions with a systematic review of the literature
Authors: Loo S W , Martin W M C , Smith P , Cherian S , Roques T W
Published: July 2012

Objectives: This study evaluates the interobserver variation in parotid gland delineation and its impact on intensity-modulated radiotherapy (IMRT) solutions.

Methods: The CT volumetric data sets of 10 patients with oropharyngeal squamous cell carcinoma who had been treated with parotid-sparing IMRT were used. Four radiation oncologists and three radiologists delineated the parotid gland that had been spared using IMRT. The dose–volume histogram (DVH) for each study contour was calculated using the IMRT plan actually delivered for that patient. This was compared with the original DVH obtained when the plan was used clinically.

Results: 70 study contours were analysed. The mean parotid dose achieved during the actual treatment was within 10% of 24 Gy for all cases. Using the study contours, the mean parotid dose obtained was within 10% of 24 Gy for only 53% of volumes by radiation oncologists and 55% of volumes by radiologists. The parotid DVHs of 46% of the study contours were sufficiently different from those used clinically, such that a different IMRT plan would have been produced.

Conclusion: Interobserver variation in parotid gland delineation is significant. Further studies are required to determine ways of improving the interobserver consistency in parotid gland definition.
MRI as a reference standard for suspected scaphoid fractures
Authors: De Zwart A D , Beeres F J P , Ring D , Kingma L M , Coerkamp E G , Meylaerts S A G , Rhemrev S J
Published: July 2012

Objectives: Some have suggested that MRI might be the best reference standard for a true fracture among patients with suspected scaphoid fractures. The primary aim of this study was to determine the rate of false-positive diagnosis of an acute scaphoid fracture in a cohort of healthy volunteers.

Methods: In a prospective study, 33 healthy volunteers were recruited and both wrists of each were scanned, except for 2 volunteers for whom only one wrist was scanned. To simulate the usual clinical context the 64 scans of healthy volunteers were mixed with 60 MRI scans of clinically suspected scaphoid fractures but normal scaphoid radiographs. These 124 MRI scans were blinded and randomly ordered. Five radiologists evaluated the MRI scans independently for the presence or absence of a scaphoid fracture and other injuries according to a standard protocol.

Results: To answer the primary question, only the diagnoses from the 64 scans of healthy volunteers were used. The radiologists diagnosed a total of 13 scaphoid fractures; therefore, specificity for diagnosis of scaphoid fracture was 96% (95% confidence interval: range 94–98%). The 5 observers had a moderate interobserver agreement regarding diagnosis of scaphoid fracture in healthy volunteers (multirater κ=0.44; p<0.001).

Conclusions: The specificity of MRI for scaphoid fractures is high (96%), but false-positives do occur. Radiologists have only moderate agreement when interpreting MRI scans from healthy volunteers. MRI is not an adequate reference standard for true fractures among patients with suspected scaphoid fractures.
Microwave characterisation and detection of wood decay
Authors: Brodie Graham , Ahmed Berhan , Jacob Mohan
Published: July 2012

The transparency of wood to microwave radiation is subject to changes in the wood's properties caused by softening of the wood material during fungal attack or the addition of moisture. A prototype microwave system that measures microwave attenuation and phase delay between two antennae was developed to detect fungal decay in wood at equilibrium moisture content. A total of twelve wooden stakes of 200 x 65 x 65 mm Pinus radiata (softwood) and twelve stakes of Eucalyptus regnans (hardwood) of the same dimensions were exposed to soil containing decay fungi for 12, 16, 20 and 24 weeks in an Accelerated Field Simulator (AFS), which is a climate conditioned room that simulates humid tropical conditions. A control set of three stakes of each wood type was also included in the experiment. Samples were washed and dried in an oven before testing with the prototype system. Orienting the antennae such that the microwave field was perpendicular to the wood grain could not distinguish between sound and decayed wood; however orienting the antennae so that the microwave fields were parallel to the wood grain and having the antennae pressed against the wood sample easily distinguished between sound wood and decayed wood. The phase delay data could not distinguish between sound or decayed wood.
Physical mechanical properties and microstructure analyses on effect of incorporating cigarette butts in fired clay bricks
Authors: Kadir A. , Mohajerani A.
Published: July 2012

Several trillion cigarettes produced worldwide annually lead to many thousands of kilograms of toxic waste. Cigarette butts (CBs) accumulate in the environment due to the poor biodegradability of the cellulose acetate filters. This paper presents some of the results from a continuing study on recycling CBs into fired clay bricks. The results show that the density of fired bricks was reduced by up to 30%, depending on the percentage of CBs incorporated into the raw materials. Similarly, the compressive strength of bricks tested decreased according to the percentage of CBs included in the mix. Nevertheless, by increasing mixing times, better quality bricks can be produced, even with the inclusion of high percentages of CBs. Longer mixing times increased dry density and compressive strength, equivalent to about 53% and 11% respectively. Microstructure observation using ESEM confirm the result by showing the apparent size of pores is reduced drastically and the distribution of pores becomes more uniform as the mixing time increases from 5 to 15 minutes, hence decreasing the porosity in the clay body which subsequently leads to a denser product with higher strength.
Information Technology, Productivity, and Asset Ownership: Evidence from Taxicab Fleets
Authors: Rawley Evan , Simcoe Timothy S.
Published: July 2012

We develop a simple model that links the adoption of a productivity-enhancing technology to increased vertical integration and a less skilled workforce. We test the model’s key prediction using novel microdata on vehicle ownership patterns from the Economic Census during a period when computerized dispatching systems were first adopted by taxicab firms. Controlling for time-invariant firm-specific effects, firms increase the proportion of taxicabs under fleet ownership by 12% when they adopt new computerized dispatching systems. An instrumental variables analysis suggests that the link between dispatching technology and vertical integration is causal. These findings suggest that increasing a firm’s productivity can lead to increased vertical integration, even in the absence of asset specificity.
The Construct of Adaptive Behavior: Its Conceptualization, Measurement, and Use in the Field of Intellectual Disability
Authors: Tassé Marc J , Schalock Robert L , Balboni Giulia , Bersani Hank , Borthwick-Duffy Sharon A , Spreat Scott , Thissen David , Widaman Keith F , Zhang Dalun
Published: July 2012

This article updates the current conceptualization, measurement, and use of the adaptive behavior construct. Major sections of the article address an understanding of the construct, the current approaches to its measurement, four assessment issues and challenges related to the use of adaptive behavior information for the diagnosis of intellectual disability, and two future issues regarding the relations of adaptive behavior to multidimensional models of personal competence and the distribution of adaptive behavior scores. An understanding of the construct of adaptive behavior and its measurement is critical to clinicians and practitioners in the field because of its role in understanding the phenomenon of intellectual disability, diagnosing a person with intellectual disability, providing a framework for person-referenced education and habilitation goals, and focusing on an essential dimension of human functioning.
An Evaluation of School Involvement and Satisfaction of Parents of Children with Autism Spectrum Disorders
Authors: Zablotsky Benjamin , Boswell Katelyn , Smith Christopher
Published: July 2012

Parental school involvement and satisfaction are unstudied in families raising a child with an autism spectrum disorder (ASD). To fill this gap, the current study utilized a national sample of families (N  =  8,978) from the 2007 Parent and Family Involvement in Education survey (U.S. Department of Education, National Center for Education Statistics, 2006–2007). Parents of children with ASDs were found to be more likely than parents of children without the disorder to attend parent–teacher conferences, meet with school guidance counselors, and help with homework. Parents of children with ASD were also more dissatisfied with the level of communication provided by the school. There was a significant positive correlation between parental school involvement and parental school satisfaction. These findings have important implications for how schools interact with families with children with ASD.
Die deutsche Arbeitsverwaltung im Generalgouvernement und die Juden
Authors: Lehnstaedt Stephan
Published: July 2012

Vorspann

Dass die polnischen Juden von der deutschen Besatzungsmacht nicht nur ermordet, sondern auch in großem Maßstab ausgebeutet wurden, erfuhr die Öffentlichkeit erstmals durch ein Buch und einen Film: Schindlers Liste. Über die Geschichte dieser Zwangsarbeit und ihre Bedingungen ist indes nur wenig bekannt. Wie groß die Defizite noch immer sind, zeigte sich erst vor wenigen Jahren, bei den deutschen Prozessen über die Verrentung jüdischer Zwangsarbeiter, die den Holocaust überlebt hatten. Umso wichtiger scheint dieser Aufsatz, der auf der Basis deutscher und polnischer Quellen erstmals präzise nachzeichnet, wie diese Zwangsarbeit organisiert war und welche Konsequenzen dies für die Betroffenen hatte.
The Indigenous Andean Concept of Kawsay, the Politics of Knowledge and Development, and the Borderlands of Environmental Sustainability in Latin America
Authors: Zimmerer Karl S.
Published: July 2012

Kawsay in Colonial and Postcolonial Borderlands

The personage of Huatya Curi, the “Baked Potato Gleaner,” figured prominently in an early colonial account of the landscape and religious mythology of the Andean people of Huarochirí, a province in the mountainous interior of Lima in the Viceroyalty of Peru. The Huarochirí manuscript, a sixteenth-century Quechua document, introduces Huatya Curi with these words: “Chay pacha cay huatya curi ñisca huacchalla micuspapas huatya cuspalla causaptinsi sutiachircan huatya curim ñispa …” ‘At that time Huatya Curi, a poor potato eater, was accustomed to living from gleaning baked potatoes, and for that reason people named him Huatya Curi …‘ (Salomon and Urioste 163; my trans.; see also Taylor 32–33). While poor, Huatya Curi was powerful; in the same passage he goes on to vanquish a mighty Andean lord, Tamta Ñamca. The demise of Tamta Ñamca sets the stage for the ascendance of Paria Caca, Huatya Curi's father, who emerges as the chief Andean deity. Huatya Curi's existence is earthly yet linked to his supernatural lineage.
An approach to forensic engineering education in the USA
Authors: Delatte Norbert
Published: July 2012

Over the past three decades, the Technical Council on Forensic Engineering (TCFE) of the American Society of Civil Engineers has worked hard to establish and promote forensic engineering as a respected profession. The ultimate goal of forensic engineering is to improve quality and safety of constructed facilities. This paper reviews the development of TCFE in the USA with particular emphasis on educational activities, which have made considerable progress over the last decade. Much work has been done in the area of integrating failure case histories, failure case studies and forensics into graduate and undergraduate engineering education. These include a book, a web site and a series of US and international workshops for faculty. The US National Science Foundation has funded three research projects to further this effort. This paper discusses different approaches to teaching with failure cases, using the Hyatt Regency walkway collapse case as an example. In addition, international developments in forensic engineering are discussed. Many of the recent efforts of the TCFE have been focused on outreach to other countries.
Yield-line theory for reinforced concrete slabs at moderately large defiexions
Authors: Morley C. T.
Published: July 2012

Summary

Conventional yield-line theory for reinforced concrete slabs is extended to allow for membrane effects and moderately large dejfexions, by isolating those membrane displacement rates 0/ the rigid slab portions which do not affect yield-line positions, and developing a method of choosing these rates so that the load estimate from the work-rate equation is stationary. For a slab with an assumed pattern of yield lines, the relationship between load-carrying capacity and deffexion can then be obtained. A number of examples are worked, with different shapes of slab and boundary conditions.
The composition of alite (tricalcium silicate) in a Portland cement clinker
Authors: Midgley H. G.
Published: July 2012

Summary

The composition of the alite (tricalcium silicate) phase in a Portland cement clinker has been determined by using an electron probe microanalyser. The molar proportions of the ions based on the unit cell are Ca 103·54 Fe 1·43, Mg 1·75, Na 0·80, K 0·18, Mn 0·02, Al 0·28 (in caldum sites); Al 0·23 (in interstitial sites); Si 34·48, Al 1·41, Ti 0·11 (in silicon sites); O 180. A comparison has been made with two other chemical analyses of tricaldum silicates and also with synthetic preparations.
A direct tensile test for concrete under long- or short-term loading
Authors: Elvery R. H. , Haroun W.
Published: July 2012

Summary

This paper describes details of a method of testing concrete in uniaxial tension. This method was devised to suit the requirements of a research programme started in 1965 to study the tensile creep andfailure of concrete. Details of the p.v.c. moulds for the manufacture of the specimens are given and a description of the arrangements for loading the specimens includes details of end attachments and a frame in which up to 30 specimens can be loaded in tension simultaneously. Typical experimental results of strain behaviour and strength are presented to indicate the performance of the method in the laboratory.
The bearing strength of concrete loaded through flexible plates
Authors: Hawkins N. M.
Published: July 2012

Summary

Approximate expressions are developed for the bearing strength of concrete axially loaded by a punch covering a limited area of the bearing plate. Depending on their stiffnesses, plates are characterized as flexible, semi-flexible or rigid. It is shown that for a flexible plate the ultimate capacity increases linearly with the plate thickness, whereas for a semi-flexible plate the rate of increase rises continuously until a maximum value is reached corresponding to the capacity for a rigid plate. The expressions predict the results for eight series of tests on concrete blocks loaded through plates ranging in thickness from 1/32 in. to 1 in.
The analysis of belite in Portland cement clinker by means of an electron-probe micro analyser
Authors: Fletcher K. E.
Published: July 2012

Summary

It is believed that the rate of hydration of dicalcium silicate in a Portland cement clinker will depend upon the type and amount of stabilizing agent present in the crystal lattice. Complete analyses are given for a belite grain in a normal British Portland cement clinker and in a sulphate-resisting Portland cement clinker. Lattice substitutions are suggested which are consistent with the analyses obtained. Belite grains in the normal and sulphate-resisting Portland cement clinkers differed in the relative proportions of Al and Fe present. The ratio of Al to Fe in the belite grains corresponded closely to the ratio of Al to Fe in the cement clinker. Difficulties which arise in the electron-probe microanalysis are discussed.
Shear in reinforced concrete beams
Authors: Regan P. E.
Published: July 2012

Synopsis

Generally acceptable compatibility and ultimate strength precepts are used in this paper to establish a physical theory of shear in reinforced concrete. Account is taken of the shear resistances of both un cracked concrete and shear reinforcement. The theory is used as the basis for the development of a simpler, but still analytic rather than empirical, design method, and the adequacy of the accuracies of both the basic and the simplified approaches is established by comparison with more than a thousand published test results.
A partial failure of limit analysis for slabs, and the consequences for future research
Authors: Wood R. H.
Published: July 2012

Synopsis

A brief discussion of the essential differences between yield-line theory and limit analysis is followed by an examination of whether or not it is possible to prove the existence or otherwise of exact solutions in all cases in limit analysis, in the light of considerable new evidence. It is maintained that the evidence is now strong enough to eliminate the possibility of exact solutions for most slabs governed by the ‘square’ yield criterion, especially continuous and encastered slabs commonly dealt with in yield-line theory. The changes that this would entail in the future direction of reinforced concrete research, and the immediate practical consequences, are discussed. It is suggested that the nodal-force theory of Johansen is a general technique which could well find application in many other branches of science.
Destructive tests on rationally designed slabs
Authors: Muspratt M. A.
Published: July 2012

Synopsis

Destructive tests on prototype reinforced concrete slabs designed by Johansen's yield-line method and Hillerborg's strip method are described. All the slabs were square, simply supported and uniformly loaded. The yield and failure characteristics of these slabs are then compared with those obtained from slabs designed by an optimum lower-bound approach. The optimum slabs contained 37 % and 16 % less reinforcing steel than the slabs designed by Johansen's and Hillerborg's methods respectively.
The effect of lead compounds in aggregate upon the setting of Portland cement
Authors: Midgley H. G.
Published: July 2012

Synopsis

Lead compounds may occur in rocks used as aggregates in concrete and those soluble in lime water will affect the rate of hardening of the concrete. The set will be delayed for 7 days by 0·8 % lead soluble in limewater, for 1 day by 0·15 %. Smaller amounts will delay the set and lower the early strength, but subsequent strengths will be as good as or better than for concretes with an equivalent aggregate without the lime-soluble lead.
Limit-state design for shear in rectangular and T beams
Authors: Regan P. E. , Placas A. , Baker A. L. L.
Published: July 2012

Synopsis

The four major modes of shear failure—diagonal tension, shearing, shear-compression and web crushing—are discussed briefly and equations are given for predicting resistances to them. The larger part of the paper is devoted to two other design criteria. An analytical approach to shear cracking at vertical web-flange junctions is outlined and its predictions are compared with the results of a limited group of tests by the authors. A semi-empirical equation is derived for the calculation of limit state of local damage resistance as determined by widths of shear cracks, and is compared with more extensive test data for various types of beam tested by the authors and others.
Some tests on the transmission length and ultimate strength of pre-tensioned concrete beams incorporating Dyform strand
Authors: Mayfield B. , Davies G. , Kong F. K.
Published: July 2012

Synopsis

Tests were carried out on 24 beams pre-tensioned with Dyform strand and 6 beams pre-tensioned with standard strand, to determine and compare transmission length, flexural strength and behaviour. It was found that the transmission length was greater for specimens incorporating Dyform strand than for those with standard strand, both at transfer and after a period of some months. Ultimate load tests indicated that the flexural behaviour of the two types of specimen was similar.
Further consideration of a mathematical model for progressive fracture of a heterogeneous material
Authors: Dougill J. W.
Published: July 2012

Synopsis

Uniaxial stress-strain curves are derived for a mathematical model designed to represent a heterogeneous material that fails in tension by progressive fracture. These results show qualitative agreement with the behaviour of real materials including mortars and concretes. The results suggest that the behaviour that occurs, after the peak stress has been achieved in a deformation-controlled test, is dependent upon the energy required to fracture the material. If this is sufficiently high, stable fracture propagation occurs. However, if the energy required for fracture is low, failure occurs by instability under reducing stress. The conditions for the occurrence of this instability are obtained in terms of the properties of the model material and the implications of this behaviour, for materials testing and the derivation of failure criteria, are briefly discussed.
Stress-strain-time relationships for concrete
Authors: Spooner D. C.
Published: July 2012

Synopsis

A pilot study has been made of the effects of strain rate upon the compressive stress-strain behaviour of prism specimens made from one particular concrete mix. The specimens were cured either in water or in air in the laboratory and tested when approximately three months old. The stress at failure was strain-rate dependent for the specimens cured in water, and the strain at failure was strain-rate dependent for the specimens cured in air.
Time-dependent strains in sealed concrete under systems of variable multiaxial stress
Authors: Jordaan I. J. , Illston J. M.
Published: July 2012

Synopsis

Sealed concrete cubes were subjected to sustained systems of uni-, bi- and triaxial stress. The uniaxial stress and one of the principal stresses in the bi- and triaxially loaded specimens were set initially at the same nominal value, and later cycled between this and a higher level while the orthogonal stresses remained constant. The strains resulting from the stress cycle were essentially the same for all three stress systems; the strains in a direction orthogonal to the stress change were found to be fully recoverable but those in the direction of the stress included an irrecoverable component. The creep Poisson's ratio was approximately the same for all stress increments. The Poisson's ratio for creep recovery rose with time from the removal of load. It is concluded that, in engineering analysis, the time-dependent strain of concrete under constant multiaxial compressive stress can be found by using a constant value of creep Poisson's ratio, equal to the static elastic value. Under variable stress, Boltzmann superposition (or a similar principle) can be applied to sum the effects of a succession of changes in stress.
Incremental deformations of under-reinforced concrete beams
Authors: Gerstle Kurt H. , Tulin Leonard G.
Published: July 2012

Synopsis

Existing ultimate strength theories for reinforced concrete structures are not sufficient to describe behaviour under cyclic loading. In particular, the phenomenon called ‘incremental collapse’ or its converse, ‘shake-dow’, must be considered. An elastic-perfectly-plastic theory has been developed, but its applicability has been questioned. If the material properties show evidence of strain-hardening, the system will shake down under cyclic loads up to and greater than the perfectly plastic limit load. This paper applies strain-hardening concepts to the theoretical response of reinforced concrete structures and verifies the predictions so obtained by comparing results with experimental responses of a set of reinforced concrete continuous beams.
The plastic flow law for reinforced concrete beams under combined flexure and torsion
Authors: Jackson Neil , Estañero Romeo A.
Published: July 2012

Synopsis

The possible application of plastic analysis to reinforced concrete structures, the members of which are subjected to both bending and twisting moments, depends not only upon their ductility but also upon a knowledge of the associated plastic flow law. An experimental investigation to determine the flow law for rectangular reinforced concrete beams under combined flexure and torsion is described in this paper. Bending and twisting rotations measured during the pseudo-plastic stage occurring near maximum load are reported for 80 beams, which included both symmetrically and unsymmetrically placed reinforcement. Typical interaction curves with their associated incremental rotation vectors are presented and the corresponding flow law is stated. The complete interaction curve is considered and the implications of this and the plastic flow law are discussed in relation to the applicability of current methods of plastic analysis to concrete structures.
Modes of failure of concrete panels exposed to high temperatures
Authors: Dougill J. W.
Published: July 2012

Synopsis

The occurrence of a mode of general spalling, in which a concrete wall panel or floor slab may be completely destroyed shortly alier the start of a fire test, is examined. Examples are given to suggest that this may be a form of compression failure, caused by strain softening, which has much in common with behaviour observed in a standard compression test. A method of analysis for the structural behaviour of a plain concrete panel is formulated in general terms. This analysis demonstrates the effects of strain softening, suggests that there are two possible modes of instability causing compression failure and shows that instability is not possible under conditions of high axial and flexural restraint. These conclusions are independent of the precise form of the stress-strain relationship but are primarily a direct consequence of the existence of a descending branch in the stress-strain curve of concrete in compression.
The effect of mix proportions upon the ultimate air-drying shrinkage of mortars
Authors: Dougill J. W. , Hobbs D. W.
Published: July 2012

Synopsis

Values are given for the ultimate air-drying shrinkage of 25 mm square mortar and paste prisms moist-cured for one week and dried at 65% R.H. and 20°C. The mortars, of water/cement ratios 0·35, 0·47, 0·59 and 0·71 and aggregate volume concentrations ranging from 40 to 70%, were made from one hatch of all ordinary Portland cement and Thames Valley flint aggregate of 5 mm maximum size. The ultimate shrinkages of the mortars are plotted as contours on a ternary diagram of mix proportions by weight and it is shown that ultimate shrinkage of the mortars is approximately proportional to water content by weight in the original mix. A comparison is made between theoretical predictions of shrinkage and the experimental values.
Determining the water content of concrete panels by using a microwave moisture meter
Authors: Figg J.
Published: July 2012

Synopsis

Sections of 1 × 2 m, sawn from full-size commercial concrete panels, were tested with a microwave moisture meter to establish calibration curves for different types of concrete cladding panel. The tests confirmed that the relationship between microwave attenuation and percentage of absorhed water for such panels was linear, but it was also found that the slope of the curve depended upon the particular construction of the concrete panel. With 10% absorbed water, the microwave attenuation varied between approximately 10 and 20 dB. Anomalous results were obtained during freezing weather and these were attributed to molecular orientation of the water in the concrete.
Deflections of prestressed concrete bridges in Japan
Authors: Kokubu Masatane
Published: July 2012

Synopsis

This paper summarizes and discusses measurements made of the deflections in service of four prestressed concrete bridges in Japan. The bridges, of long-span and central-hinge type, were constructed by the cantilever method. The paper discusses a simplified formula for calculating the deflection occurring after hinges have been joined.
Moment redistribution in continuous prestressed concrete beams
Authors: Priestley M. J. N. , Park R.
Published: July 2012

Synopsis

In a previous paper relationships between moment and average curvature were developed for prestressed sections subjected to constant moment. The variation of stiffness due to concrete tension between cracks was taken into account. These relationships are now used to determine the moment-load and load-deflection curves for continuous beams up to the onset of concrete crushing. The results of an experimental programme on two-span continuous beams are presented and show close agreement with theoretical results.
Steel-fibre-reinforced mortar: a technique for producing composites with uniaxial fibre alignment
Authors: Hannant D. J. , Spring N.
Published: July 2012

Synopsis

A technique is described by which short steel fibres can be aligned parallel to the direction of tensile stress in mortar beams to be subjected to flexural loading. A combination of vibration and mechanical alignment enables the load carried by the beam to be doubled in comparison with that achieved by using vibration alone.