bluuebunny/crossref_metadata_2025 huggingface dataset:
Pancreatic solid pseudopapillary tumours – EUS FNA is the ideal tool for diagnosis
Authors: Stoita Alina , Earls Peter , Williams David
Published: August 2010

Background:  Solid pseudopapillary tumour (SPT) is a rare tumour of the pancreas with low malignant potential affecting mainly young women difficult to diagnose preoperatively. The aim of this study is to describe the endoscopic ultrasound (EUS) features and utility of EUS‐guided fine needle aspiration (FNA) in diagnosing these tumours.

Methods:  A retrospective analysis of SPTs identified in a tertiary institution EUS database between April 2002 and April 2009 was performed. Medical records, imaging, EUS features, cytology and histology specimens were reviewed. Patients were followed up until April 2009.

Results:  Seven cases of SPTs were indentified out of 2400 EUS performed. All patients were females with a mean age of 41 years (range 22–69). The tumours were solitary with a mean diameter of 2.9 cm (range 2–4.3 cm). Five tumours were located in the body and tail of the pancreas and two in the neck. All lesions were hypoechoic, heterogenous and well circumscribed, with five having a cystic component and two having a calcified rim. FNA using a 22‐gauge needle was performed in six cases with no complications. A preoperative diagnosis of SPT based on cytology was obtained in 5/6 cases (83%). Surgical resection was done in six cases with confirmation of SPT and no metastatic disease.

Conclusion:  EUS‐guided FNA is a minimally invasive, safe and reliable way of diagnosing SPT by providing characteristic cytological specimens. Definitive preoperative diagnosis leads to targeted and minimally invasive surgical resection.
Outcomes of the overlay graft technique in tympanoplasty
Authors: Ryan Jennifer E. , Briggs Robert J. S.
Published: August 2010

Background:  This audit was undertaken to review the outcomes achieved with the overlay graft technique of tympanic membrane repair in tympanoplasty surgery.

Methods:  The charts of all patients who underwent tympanoplasty, in whom an overlay graft technique of temporalis fascia tympanic membrane repair was used, between 1994 and 2007 were reviewed. Information with respect to patient demographics, presence of cholesteatoma or active infection and perforation size was documented. Details of the surgical procedure and clinical outcomes and pre‐ and post‐operative hearing thresholds were recorded in a computer database.

Results:  A total of 147 overlay graft procedures were performed in 130 patients. Graft failure with reperforation occurred following five procedures, for an overall success rate of 96.6%. Eighty Type 1 tympanoplasty procedures were performed in which one failure occurred for a 98.75% success rate. Overlay grafting was combined with intact canal wall mastoidectomy (ICW) in 38 cases and with modified radical mastoidectomy (MRM) in 17 cases for a success rate of 93.8 and 95%, respectively. Delayed graft healing as a result of infection, problems such as epithelial pearl, blunting and myringitis occurred in 39 cases (26.5%). Thirty‐one cases underwent procedures for ossicular chain reconstruction, 21 of which were 2nd stage procedures. Hearing outcomes were significantly better with Type 1 tympanoplasty compared with ICW or MRM procedures.

Conclusion:  This review demonstrates the overlay graft technique of tympanoplasty to be highly successful for tympanic membrane repair, particularly for the more difficult cases such as revision surgery, subtotal perforations and mesotympanic cholesteatoma.
Are there anatomical barriers to laparoscopic donor nephrectomy?
Authors: Crane Catherine , Lam Vincent W. T. , Alsakran Abdulrahman , Vasilaras Arthur , Lau Howard , Ryan Brendan , Pleass Henry C. C. , Allen Richard D. M.
Published: August 2010

Background:  The aim of this study was to analyse the effect of the right donor kidney and multiple arteries, on donor and recipient outcomes in the era of laparoscopic live donor nephrectomy (LLDN).

Methods:  We retrospectively analysed the 200 donors and recipients who underwent a planned laparoscopic nephrectomy at two hospitals between September 1998 and December 2006. The impact of donor right kidney and multiple donor renal arteries on operative time, hospital stay, graft function, and donor and recipient complications were analysed.

Results:  Of the total cohort (n = 200), 140 (70%) were classified as Simple LLDN (left live donor kidney with single renal artery). The Complex LLDN group (n = 60) contained all right‐sided kidney (n = 28) and left‐sided kidneys with multiple renal arteries (n = 32). Baseline characteristics, extraction time, conversion to open, length of admission, overall graft function and complication rates were similar between the simple and complex groups. The second warm ischaemic time in the Simple LLDN group was slightly shorter than the Complex LLDN group (32 versus 36 min P = 0.016). The 1‐month post‐operative recipient serum creatinine level was lower in the Simple LLDN group when compared with the Complex LLDN group (117 versus 125 µmol/L P = 0.025). There was no difference in post op dialysis, acute rejection within 3 months or graft survival between the Simple and Complex LLDN groups.

Conclusion:  Laparoscopic procurements of right kidneys and kidneys with multiple arteries were safe and yielded kidneys with excellent function comparable with those of laparoscopic left donor nephrectomy with single artery.
Surgical anatomy of the external branch of the superior laryngeal nerve
Authors: Whitfield Patricia , Morton Randall P. , Al‐Ali Saad
Published: August 2010

Background:  The variations in the anatomy of the external branch of the superior laryngeal nerve (EBSLN) are generally classified according to the relationship of the nerve to the superior thyroid artery, or the superior pole of the thyroid. Both artery and superior pole are themselves variable landmarks, and therefore are not consistent between subjects. We sought to examine EBSLN anatomy in relation to alternate, more consistent surgical landmarks.

Methods:  Fifteen hemi‐larynges from 20 embalmed human cadavers were dissected anatomically. Each nerve was categorized using established classification systems, and terminal branching patterns were also noted. Nerve location was recorded in relation to three different constant anatomical structures: the laryngeal prominence, midline junction of the cricothyroid muscles and ipsilateral cricothyroid joint.

Results:  All cadavers were of European descent. The EBSLN had two branches to the cricothyroid muscle in 34% of cases. The EBSLN anatomical types found were mainly Cernea type 1 (80%), with 7% type 2a and 13% type Ni. An EBSLN was more likely to lie in an ‘at risk’ location if the subject was less than 160 cm tall. The EBSLN entered the crico‐thyroid muscle at a median distance of 14 mm lateral from the laryngeal prominence and 8 mm inferiorly. The median distance from the medial‐most point of the cricothyroid muscle junction was 14 mm laterally and 14 mm superiorly, and from the cricothyroid joint the entry lay a median distance of 10 mm superiorly and 11 mm medially.

Conclusions:  The variability of EBSLN anatomy is again evident, as is the need for careful and knowledgeable surgical technique. New surgical landmarks for the relations of the insertion of the EBSLN reveal a deployment range for each, but one of more of these landmarks may prove useful in thyroid surgery.
INSULIN SECRETORY CAPACITY, β‐THROMBOGLOBULIN and BLOOD VISCOSITY IN LONG STANDING, NON‐INSULIN DEPENDENT DIABETICS WITH and WITHOUT MICROANGIOPATHY
Authors: BARNETT A. H. , SMITH J. R.
Published: August 2010

A comparison was made of insulin secretion in response to i.v. glucose between non‐insulin dependent diabetics with and without severe microangiopathy. During i.v. glucose tolerance testing those with complications had significantly lower serum insulin concentration (at 40 and 60 min 15.2 ± 2.9 and 11.7 ± 2.5 mll‐1 respectively) than those without (26.1 ± 4.7 and 24.3 ± 3.6 mU‐1, p <0.01). The differences were also significant when insulin increment above basal was determined. All subjects had raised plasma beta‐thromboglobulin concentration (indicating increased tendency to platelet aggregation), but with no significant difference between the two groups. There was also no difference in fasting glucose, kg values, HbAI or blood viscosity. We conclude that non‐insulin dependent diabetics with severe microangiopathy have significantly reduced insulin secretory capacity in response to i.v. glucose when compared with those without.
A RADIOIMMUNOASSAY FOR THE DETECTION OF CIRCULATING ANTI‐GLOMERULAR BASEMENT MEMBRANE ANTIBODIES
Authors: HOLDSWORTH S. R. , WISCHUSEN N. J. , DOWLING J. P.
Published: August 2010

A fluid phase radioimmunoassay (RIA) has been established for the detection of circulating anti‐glomerular basement membrane (GBM) antibodies. Antibodies were detected by binding with a collagenase solubilised, immunochemically purified, radiolabeled extract of human particulate GBM. Sera from 108 patients with a variety of histological types of glomerulonephritis (GN) were assessed for the presence of antibodies. Likely positive sera were those from patients with clinical features of rapidly progressive glomerulonephritis (RPGN) with crescentic or diffusely proliferative GN and linear staining of their GBM's with IgG. Thirty one of 35 sera from such patients were positive in the RIA. Sera from 14 patients with RPGN but with granular IgG deposition (i.e. immune complex related GN) were all negative for anti‐GBM antibodies as were sera from 59 patients with a variety of non‐crescentic non RPGN without linear IgG. Comparison of the RIA with conventional indirect immunofluorescence (IIF) showed that the RIA had a higher detection rate of antibodies in likely positive sera (19/21 RIA: 16/21 IIF) lower false positive detection rate with sera from patients without GN (0/26 RIA: 2/26 IIF) and was three to four times more sensitive in serial dilution studies.
EARLY CROSSOVER OF INDUCTION CHEMOTHERAPY IN SMALL CELL LUNG CARCINOMA
Authors: ROBINSON P. C. , DREW M. J. R. , GILL P. G. , McLENNAN G. , ANTIC R.
Published: August 2010

The aim of this trial was to assess whether early crossover induction chemotherapy would improve the complete response rate in patients with small cell lung carcinoma. Tumour markers were defined in all 48 patients at diagnosis. The patients were reassessed after three and six cycles of chemotherapy and classified as having either complete, partial or non response of tumour on each occasion.

Initial induction therapy consisted of cyclophosphamide, vincristine and adriamycin (T1). The therapy of the patients with no tumour response was changed to a regimen (T2) consisting of VP16‐213, procarbazine, CCNU and high dose methotrexate with folinic acid rescue. The patients with partial tumour response were randomised to receive either T1 or T2, while patients with complete tumour response continued with T1.

In those patients classified initially as having partial tumour response, crossover chemotherapy did not improve tumour response or survival. Similarly, in patients with no tumour response there was not an acceptable improvement.

We conclude that non cross resistant crossover chemotherapy using these drug regimens confers no added benefit when compared with continuing the initial therapy.
COMPARISON OF WET and DRY AEROSOL SALBUTAMOL
Authors: HARRISON B. A. , PIERCE R. J.
Published: August 2010

Wet aerosol and metered dose inhaler (MDI) modes of inhalation of salbutamol were compared in ten asthmatic patients with severe, reversible airways obstruction and in ten chronic bronchitic patients with severe, poorly reversible airways obstruction. The responses to cumulative doses to 800 μgm (8 times 100 μgm) by MDI and 10 mg (4 times 0.5 ml of 0.5% standard solution) by wet aerosol were studied. From maximum expiratory flow‐volume curves, measurements were made of FEV1, FVC, PEFR, Vmax 50% and Vmax 75%, and pulse and blood pressure responses to cumulative doses of salbutamol were measured. In both groups of patients there was no significant difference between the two modes of inhalation either for each treatment interval or for the maximal response in any of these indices.
THIAMIN INADEQUACY IN INFANTS: LACK OF EVIDENCE OF AMPROLIUM IN EGG YOLK
Authors: THORNBER E. J. , MARRIOTT J. M. L. , ELLIOTT L. E. , MASSERA F. C. , KERR D.
Published: August 2010

This study investigated the hypothesis that the consumption of egg yolks might lead to thiamin inadequacy in infants because of the possible contamination of the egg yolks with amprolium. Earlier workers showed that the presence of amprolium in the diet inhibits the absorption of thiamin. Amprolium is added to some poultry feeds to control coccidiosis: it is readily incorporated in the egg yolk and egg yolk is one of the solid foods offered to infants at weaning. We found that under current commercial poultry feeding practices in WA it is extremely unlikely that any amprolium would be present in commercial eggs or poultry. Amprolium was undetectable in eggs purchased at several retail outlets. Thus there is no evidence that consumption of egg yolk contributes to thiamin inadequacy in infants.
PATTERNS OF STROKE: AN ANALYSIS OF THE FIRST 700 CONSECUTIVE ADMISSIONS TO THE AUSTIN HOSPITAL STROKE UNIT
Authors: CHAMBERS B. R. , DONNAN G. A. , BLADIN P. F.
Published: August 2010

An analysis is presented of the first 700 admissions to the Austin Hospital Stroke Unit with special emphasis on the incidence of the various patterns of stroke and the underlying mechanisms involved. There were 616 admissions for confirmed stroke events–the remainder were for events simulating stroke. Three hundred and fifty‐three (57.3% of stroke events) were for cortical (including retinal) ischaemic events. Of these, arterial lesions were demonstrated in 55% and suspected in 20% whilst embolism from the heart probably accounted for 14% of events. No cause was determined in 11% despite complete investigation. Where arterial lesions were found, they were extracranial in 85%. There were 140 cases of internal capsular ischaemia (22.7% of stroke events) and 16 cases (2.6%) for which the exact site of ischaemia was not determined, although it was presumed to have occurred within the carotid territory. Vertebrobasilar ischaemic events were responsible for 71 admissions (11.5%). There were 36 cases of primary intracerebral haemorrhage (5.8%).

This survey has highlighted some aspects of stroke requiring further research. These include the elucidation of cortical and retinal ischaemic events of unknown aetiology, the possible role of large vessel lesions in the pathogenesis of capsular ischaemic events and pathologic mechanisms involved in ischaemic events of the vertebrobasilar territory.
The efficacy of chelation therapy and factors influencing mortality in lead intoxicated petrol sniffers
Authors: Burns C. B. , Currie B.
Published: August 2010

Backgmund:The use of chelating agents to treat patients with petrol sniffing encephalopathy has been controversial, since alkyllead additives in petrol are not chelatable. A high mortality has also been reported in hospitalised petrol sniffers.

Aims: (i) Evaluate the efficacy of chelating agents in mobilising lead for excretion and lowering blood lead; (ii) Review factors contributing to mortality in hospitalised petrol sniffers.

Methods: All males chelated between 1992–1993 were studied (n = 20). Blood and urinary lead were measured daily before and during chelation then twice weekly until discharge. Parenteral calcium disodium edetate (EDTA) and dimercaprol (BAL) were administered together, every six hours for five days, seven patients subsequently received oral D‐penicillamine until discharge. Clinical details were reviewed for eight patients with petrol sniffing encephalopathy who died between 1990–1994.

Results: Urinary lead excretion substantially increased during parenteral chelation (median excretion=I13 μM/L days, compared with pre‐chelation excretion =1.1 μM/day). Median blood lead concentration fell from 4.83 μM/L (pre‐chelation) to 1.91 μM/L (post‐chelation). D‐Penicillamine did not appear to increase urinary lead excretion appreciably. All eight deaths followed sepsis; five from complications of aspiration pneumonia.

Conclusions: Airway maintenance and management are crucial for survival in these patients. In the short‐term, parenteral chelation was effective in mobilising lead for excretion and reducing blood lead in encephalopathic petrol sniffers and was comparable to cases of inorganic lead intoxication. However, as in the treatment of inorganic lead intoxication, the long‐term efficacy of chelation for petrol sniffers remains controversial. Prevention strategies against petrol sniffing at a community level are recommended.
Focal segmental glomerulosclerosis and Guillain–Barre syndrome associated with Campylobacter enteritis
Authors: Lim A. , Lydia A. , Rim H. , Dowling J. , Kerr P.
Published: August 2010

Previous reports have noted an association between membranous nephropathy and focal segmental glomerulosclerosis with Guillain–Barre syndrome. We report a case of Campylobacter enteritis, which was complicated by both focal segmental glomerulosclerosis of the collapsing variety and Guillain–Barre syndrome, and propose that Campylobacter may be the common link between the glomerular disease and Guillain–Barre syndrome. We also briefly review previous reports of kidney disease associated with Campylobacter infection.
Hepatitis B virus reactivation following immunosuppressive therapy: guidelines for prevention and management
Authors: Lubel J. S. , Testro A. G. , Angus P. W.
Published: August 2010

It is well known that immunosuppressive drugs or cancer chemotherapy can stimulate replication of hepatitis B virus (HBV) and precipitate severe flares of HBV infection. The risk of this syndrome of ‘reactivation hepatitis B’ is highest in haematopoietic stem cell or solid organ transplant recipients and in those undergoing chemotherapy for haematological malignancies; however, it has been described following almost any form of immunosuppressive treatment. Fortunately, it can be largely prevented by prophylactic therapy with oral anti‐HBV nucleoside/nucleotide analogues. Importantly, chronic HBV infection is usually asymptomatic, and most patients at risk are likely to be unaware that they carry the infection. Thus, the key to avoiding this potentially fatal complication of immunosuppressive treatment is to ensure that all patients at risk of chronic HBV infection are screened for the disease before commencing immunosuppressive treatment or chemotherapy.
Two rare severe and fulminant presentations of Q fever in patients with minimal risk factors for this disease
Authors: Munckhof W. J. , Runnegar N. , Gray T. J. , Taylor C. , Palmer C. , Holley A.
Published: August 2010

We described two rare severe and fulminant clinical presentations of acute Q fever. The first patient had severe multiorgan failure. The second patient had fever and severe cholera‐like diarrhoea. Coxiella burnetii polymerase chain reaction on blood or serum can be clinically useful in the diagnosis of acute Q fever before seroconversion.
Exploring pathways to improve indigenous organ donation
Authors: Stephens D
Published: August 2010

Australia has one of the worst organ donation rates in the western world. The consequence of this is that the waiting list for life‐saving transplants is increasing. Australia has a highly successful transplant programme, but a limited number of organs are donated. Unfortunately, Aboriginal people are over‐represented in the organ‐failure patient group – particularly in end‐stage renal disease. Renal transplantation has the potential to improve quantity and quality of life for Aboriginal people with renal failure. Aboriginal people have a right to be given the same opportunities as non‐indigenous people to donate their organs at the end of life and improve the transplantation rates among their own people. The most effective way to improve indigenous donation rates will be through improving the knowledge of Aboriginal people about organ donation. There are cultural complexities and end‐of‐life rituals that make the decision to donate organs difficult, but these issues do not preclude a family from making the decision to donate organs at the end of life. We need to provide Aboriginal communities with appropriately presented information to give them a basis for making an informed decision about organ donation. Equity of access is important. Cultural competence of requestors is important. Consultation, communication and education are the way forward.
Managing confidentiality in illicit drugs research: ethical and legal lessons from studies in remote Aboriginal communities
Authors: Clough A. , Conigrave K.
Published: August 2010

Assuring participant confidentiality in illicit drugs research has raised legal questions and challenges both for researchers and ethics committees. There are similar challenges for clinicians. To study cannabis use in Aboriginal people in Arnhem Land (Northern Territory), a risk‐management approach was successful. Aboriginal participants were informed in their own language that confidentiality could not be assured if they disclosed information about illegal behaviours. Researchers avoided questions of intrinsic interest to law enforcement. Relationships between researchers and study participants and the integrity of the study were preserved. These considerations have relevance for clinicians as well as researchers dealing with the influence of illicit behaviours on health.
Deviation from published guidelines in the management of primary spontaneous pneumothorax in Australia
Authors: Kelly A.‐M. , Clooney M. ,   Spontaneous Pneumothorax Australia Study Group
Published: August 2010

There are a several published guidelines recommending treatment pathways for patients with primary spontaneous pneumothorax (PSP). Little is known about how these patients are actually treated in Australia. The aim of this study was to establish treatment patterns for Australian patients with PSP. This was a multicentre retrospective observational study conducted at 19 emergency departments across Australia of adult patients with PSP presenting in the calendar year 2005. In Australia, there is considerable deviation from published guidelines for the management of PSP. In light of the lack of high‐quality evidence to assist in choosing treatment approaches, a randomized controlled trial of management strategies is recommended.
Advances in percutaneous treatment for adult valvular heart disease
Authors: Wong M. C. G. , Clark D. J. , Horrigan M. C. G. , Grube E. , Matalanis G. , Farouque H. M. O.
Published: August 2010

Valvular heart disease occurs in 2–3% of the general population with an increase in prevalence with advancing age. The aetiology of valvular heart disease has evolved in recent decades with degenerative aortic and mitral valve disease supplanting rheumatic heart disease as a primary cause. The common valve lesions to be discussed in this article are aortic stenosis and mitral regurgitation. The traditional approach to calcific aortic stenosis when either symptoms or left ventricular impairment develops is surgical aortic valve replacement and it remains a treatment with excellent outcomes. In recent years there has been interest in less invasive approaches, including percutaneous and transapical aortic valve implantation. With refinements in technology these approaches are becoming a potential treatment option, primarily for high‐risk patients who may otherwise be unsuitable for traditional open surgical treatment. Catheter‐based approaches for mitral valve disease are also evolving. Mitral regurgitation may often be the result of mitral annular dilatation seen in patients with an enlarged left ventricle or left atrium. Percutaneous implantation of a constricting device in the coronary sinus, which lies in close proximity to the mitral annulus, results in a change to the geometry of the mitral valve and reduced regurgitation. Another technique in patients with degenerative mitral regurgitation is the endovascular edge‐to‐edge repair in which coaptation of the mitral valve leaflets can be improved with a percutaneously deployed clip. Small patient series indicate that these new techniques are promising. As such, advances in percutaneous interventional and surgical approaches have the potential to further improve outcomes for selected patients with valvular heart disease.
A fatal case of phlegmonous colitis in chronic hepatitis C receiving combination interferon and ribavirin therapy
Authors: Pang S. H. , De Silva K. , Napoli J. , Jones B. E.
Published: August 2010

Phlegmonous colitis is an acute suppurative infection of the large bowel that is rarely described, rapidly fatal and often escapes clinical attention. Patients with chronic hepatic diseases appear to be predisposed to this condition. We report a novel case of fatal phlegmonous colitis in a cirrhotic patient receiving combination pegylated interferon and ribavirin for chronic hepatitis C, highlighting the importance of early recognition of this aggressive infectious entity.
Acute Q fever in pregnancy: report and literature review
Authors: Denman J. , Woods M.
Published: August 2010

Acute Q fever in pregnancy is uncommon, but is probably underrecognized. It results in a significant risk of adverse pregnancy outcome and also predisposes to the development of chronic Q fever in the mother. Here, we review the clinical features, epidemiology, treatment and follow‐up of acute Q fever in pregnancy. The potential for transmission of Coxiella to the neonate and birthing suite staff will also be highlighted.
FATIGUE CRACK GROWTH IN CORROSIVE ENVIRONMENTS
Authors: Panasyuk V. V. , Ratych L. V. , Dmytrakh I. N.
Published: August 2010

Abstract— An analysis is presented of factors causing fatigue crack resistance in metals exposed to liquid corrosive environments. A new approach involving invariant diagrams is proposed that takes simultaneous account of the stress‐strain state and the electrochemical conditions at the tip of a crack. Variations in electrochemical conditions at the tip of a stationary crack and the relationship between the electrochemical conditions at the crack tip and the fatigue crack growth rate in aqueous corrosive environments are discussed with the aid of these diagrams.
A MODEL FOR CALCULATING THE FATIGUE CRACK OPENING LOAD AND ITS APPLICATIONS
Authors: Qingzhi He
Published: August 2010

Abstract— A model is proposed for calculating the fatigue crack opening load based on the concept of residual strain in the overload plastic zone. An equation relating the fatigue crack opening load to loading parameters is given. The model is used to evaluate the retardation effect due to overload under various loading conditions. It is found that the calculated results agree with test data.
THE INFLUENCE OF NITROGEN ON HIGH TEMPERATURE LOW CYCLE FATIGUE BEHAVIOUR OF AUSTENITIC STAINLESS STEELS
Authors: Nilsson J.‐O.
Published: August 2010

Abstract— High strain fatigue properties of AISI 316, AISI 316N and Sandvik 253MA have been investigated at 600°C. The two latter alloys, which contain significant amounts of N, exhibit a higher resistance to fatigue than 316. This effect is accompanied by a planar dislocation slip mode in 316N and 253MA as opposed to a wavy slip mode in 316. The results provide strong evidence that N improves fatigue strength in austenitic stainless steels, by inhibiting cross‐slip of screw dislocations.
CREEP LIFE OF AISI 316 STAINLESS STEEL SUBJECTED AT 550°C TO STEP CHANGES IN TENSILE LOAD
Authors: Kelly D. A. , Singh G.
Published: August 2010

Abstract— A phenomenological model of cumulative creep damage combining simulated grain boundary cavitation with internal redistribution of stress is developed and matched to constant load tensile creep data for an AISI 316 stainless steel tested at 550°C. The model is shown to predict the creep life of the material when it is subjected to single step changes in load provided the strain rates subsequent to the change are imposed in the model. It is inferred that this supports current suggestions that cavitation failure may be strain controlled.
THE GROWTH OF SMALL CORROSION FATIGUE CRACKS IN ALLOY 2024
Authors: Piascik R. S. , Willard S. A.
Published: August 2010

Abstract—The corrosion fatigue crack growth characteristics of small surface and corner cracks in aluminium alloy 2024 is established. The damaging effect of salt water on the early stages of small crack growth is characterized by: (1) crack initiation at constituent particle pits, (2) intergranular microcracking for a≤100μm, and (3) transgranular small crack growth for a≥100μm. In aqueous 1% NaCl and at a constant anodic potential of −700 mVSCE, small cracks exhibit a factor of three increase in fatigue crack growth rates compared to laboratory air. Small cracks exhibit accelerated corrosion fatigue crack growth rates at low levels of ΔK(< 1 MPa√m) below the long crack ΔKthvalue. When exposed to Paris regime levels of crack tip stress intensity, small corrosion fatigue cracks exhibit growth rates similar to that observed for long cracks. Similar small and long crack growth behavior at various levels ofRsuggest that crack closure effects influence the corrosion fatigue crack growth rates of small cracks for a≥100 μm. Contrary to the corrosion fatigue characteristics of small cracks in high strength steels, no pronounced chemical crack length effect is observed for alloy 2024 exposed to salt water.
MICRO‐CRACK GROWTH AND LIFE PREDICTION OF A 1CrMoV STEEL UNDER AXIAL‐TORSIONAL LOW CYCLE FATIGUE AT 550°C
Authors: Sakurai S. , Fukuda Y. , Isobe N. , Kaneko R.
Published: August 2010

Abstract— Micro‐crack behaviour under axial and torsional loading at 550°C was observed by replica techniques. Cracking behaviour and micro‐damage observations were correlated using several parameters that are based on equivalent strain parameters. From the observations, micro‐cracking of the oxide films at the crack tip in the strain localized regions seems to be a dominant micromechanism of fatigue crack growth. The maximum principal strain has been identified as an important parameter in multiaxial fatigue at high temperature. A good correlation was obtained between the principal strain range and the crack growth rate. Finally, a life prediction method was proposed based on maximum crack length.
DYNAMIC CRACK PROPAGATION AND CRACK ARREST BEHAVIOUR IN RELATION TO BRITTLE INTERGRANULAR AND CLEAVAGE FRACTURE
Authors: Jaeckels H. , Iung T. , Pineau A.
Published: August 2010

Abstract— Conventional mechanical tests and fracture mechanics experiments were carried out at – 196°C on a low alloy steel (A508 class 3) which was investigated under two different conditions: (i) a reference condition in which the failure mode was cleavage and (ii) an embrittled condition in which the fracture mode was either partly or predominantly intergranular fracture. These experiments, performed with a new specimen geometry, a ring specimen instrumented to measure also the crack velocity, were used to determine the fracture toughness at crack initiation (KIc) and at crack arrest (KIa). It is confirmed that the reduction in KIc measured in the embrittled material is associated with the appearance of intergranular fracture. It is also shown that KIa, determined by a static analysis decreases rapidly with crack velocity when the fracture mode is predominantly cleavage. On the other hand, KIa, corresponding to intergranular fracture seems to be much less dependent on crack speed. This difference in the sensitivity of both modes of brittle fracture to crack velocity is briefly discussed.
A SIMPLIFIED APPROACH TO CRACK GROWTH PREDICTION IN A CRANKSHAFT
Authors: Guagliano M. , Vergani L.
Published: August 2010

Abstract— Fracture mechanics analyses are carried out on a cracked machine element of complex geometry to predict its fatigue behaviour. Usually, in order to obtain reliable values of stress intensity factors, it is necessary to realize three‐dimensional meshes or to utilize the energy approach. An alternative, simplified and approximate approach is proposed here. It is based on the construction of simple two‐dimensional models to obtain accurate values of the geometry factors of the component at the deepest point of the crack. Experimental tests show that the relation between the depth and the length of the crack on the free surface is linear. Hence it is possible to reduce the problem to two dimensions with a consequent saving of calculation time. A comparison with experimental data indicates that a satisfactory prediction is obtained by the proposed method.
ESTIMATED AND EXPERIMENTAL FATIGUE LIVES OF 30CrNiMo8 STEEL UNDER IN‐AND OUT‐OF‐PHASE COMBINED BENDING AND TORSION WITH VARIABLE AMPLITUDES
Authors: ŁAgoda T. , Macha E.
Published: August 2010

Abstract— Calculated fatigue lives, based on three criteria for multiaxial random fatigue, were compared with lives obtained from tests on cylindrical specimens of 30CrNiMo8 steel subjected to in‐ and out‐of‐phase bending and torsion at variable amplitudes. In the chosen fatigue criteria the expected position of the fracture plane, determined from a variance method for the equivalent stress, were taken into account. The equivalent stress history was related to the rain flow method and fatigue damage was evaluated from the Palmgren–Miner hypothesis. It has been shown that the expected fatigue fracture planes agree with those determined by experiments. The most realistic estimations of fatigue life were obtained by the criterion of maximum shear and normal stresses on the fracture plane using a modified shear stress.
PREDICTION OF THE COMPETITION BETWEEN SURFACE AND INTERNAL FATIGUE CRACK INITIATION IN PM ALLOYS
Authors: de Bussac A.
Published: August 2010

Abstract— Low cycle fatigue (LCF) testing of powder metallurgy (PM) superalloys has determined that LCF cracks initiate from defects such as pores and ceramic inclusions located either at the surface or internally. The ratio of surface‐to‐internal crack initiation sites depends upon experimental conditions. In the current work, a probabilistic model is presented that describes the competition between these two failure mechanisms from a single experimental parameter, μ. The model predicts the size distribution of defects which initiate LCF cracks, as well as the proportion of specimens which fail as a result of internally located defects. Model predictions were found to correlate well with experimental LCF data obtained from a N18 PM Ni‐base superalloy. The model further enables evaluation of a “size effect”, as it predicts that internal crack initiation is favoured for larger components/specimens.
PREDICTION OF THE FATIGUE LIFE OF LASER WELDED STAINLESS STEEL JOINTS
Authors: Dattoma V.
Published: August 2010

Abstract— A fatigue scatter band has been computed for laser welded austenitic stainless steel joints. These laser welded steels have a very small heat affected zone. The unified scatter band provided by standards for welded structural steels does not adequately describe the trend of the experimental data of laser welded steels and this makes their design parameters scarcely realistic. The scatter band proposed in this paper has been computed by re‐sorting experimental data relative to joints with high stress concentration factors and has subsequently been assessed with data relevant to butt welded joints.
A STUDY OF THE GROWTH OF SMALL FATIGUE CRACKS IN A HIGH STRENGTH STEEL USING A SURFACE ACOUSTIC WAVE TECHNIQUE
Authors: Nelson D. V. , Yuce H. H. , Chow L. G.
Published: August 2010

Abstract— An ultrasonic surface acoustic wave technique for studying the growth behaviour of small fatigue cracks is described. The technique allows crack depth and opening stress to be monitored continuously during the course of a fatigue test. Results are given for a 1740 MPa yield strength, silicon‐modified, AISI 4340 steel tested under zero‐to‐tension cyclic loading. Good agreement is shown between acoustically determined crack depth and that measured by post‐fracture optical microscopy. The monitoring of changing crack depth‐to‐surface length ratios during tests is also demonstrated. Acoustically determined crack opening stresses were found to be about 10% higher than values determined by measurements of crack tip opening displacements by scanning electron microscopy. Effects on crack growth of two different specimen surface preparations, electropolishing and diamond paste polishing, are also reported. Growth rates in electropolished specimens were as much as an order of magnitude higher than in diamond paste polished specimens which had a shallow but significant layer of compressive residual stress.
EFFECT OF RE‐COLD WORKING ON FATIGUE LIFE ENHANCEMENT OF A FASTENER HOLE
Authors: Bernard M. , Bui‐Quoc T. , Burlat M.
Published: August 2010

Abstract The present study aims to assess the additional fatigue life enhancement obtained by coldworking a previously cold expanded plate hole. Two different methods of performing the second coldworking were considered, i.e. moving the mandrel in the same direction as for the first coldworking or moving it in the opposite direction. A three dimensional finite element analysis for establishing the residual stress field induced by two successive coldworkings (5.58% then 4.8%) was carried out. Al 7475‐T7351 specimens with a central hole were cold expanded at 5.58%, subjected to cyclic loading at constant amplitude for a predetermined life fraction (on the basis of 5.58% cold expanded hole fatigue life) and then re‐coldworked at 4.8%. After this rework, the specimens were again subjected to the same fatigue loading conditions until failure. During cycling, the fatigue crack extension was monitored using a video‐camera in order to determine the coldworking effect on both the initiation period and the propagation life.

The fatigue test results have shown that a second coldworking may enhance the fatigue life of an already coldworked hole. For a given cyclic loading level, the beneficial effect depends upon the applied life fraction before reworking. The direction of the mandrel movement during the second coldworking has no noticeable influence on the additional fatigue life improvement. These experimental results have been analyzed with reference to the calculated residual stress field.
A NEW APPROACH TO FATIGUE THRESHOLD
Authors: Wu X. J. , Wallace W. , Koul A. K.
Published: August 2010

Abstract Conventionally, the fatigue threshold of a long‐crack is obtained by load shedding using a constant normalized K‐gradient, as recommended by ASTM E‐647. However, this load shedding procedure often causes the crack opening displacement to decrease with increasing crack length, which may trigger crack closure. In this study, load shedding tests were conducted in load control following a power‐law load shedding schedule such that the crack opening displacement was kept at a relatively constant level. Using this new testing procedure, it is shown that crack closure is not always as high as that associated with the ASTM recommended procedure at a given ΔK. Comparisons of fatigue crack growth rates under identical testing parameters, but with different closure levels produced by the two load shedding procedures, have been made for several structural alloys. The extrinsic shielding of the crack tip zone via crack closure has also been examined using an energy approach for these alloys. On the basis of these analyses, the true effective stress intensity range is evaluated for fatigue crack propagation and the role of crack closure in creating a fatigue threshold is re‐assessed.
CALIBRATION OF THE LOCALIZED DCPD METHOD FOR CRACK SHAPE MEASUREMENT USING THE BOUNDARY ELEMENT METHOD
Authors: Harrington D. S. , Bell R. , Tan C. L.
Published: August 2010

Abstract The boundary element method (BEM) is used to develop an effective calibration method for the localized DCPD crack measurement technique. Electrical potentials are obtained from a three‐dimensional BEM analysis of a flat plate specimen containing a pair of coplanar coalescing surface cracks. This calibration technique is developed as part of a study of fatigue crack propagation and coalescence. The development of this calibration technique is presented with an evaluation based on the experimental results.
PRACTICAL STRESS EXPRESSIONS FOR STRESS CONCENTRATION REGIONS
Authors: Xu R. X. , Thompson J. C. , Topper T. H.
Published: August 2010

Abstract Approximate equations were developed to describe the stress fields in stress concentration regions. A uniaxial tension loading condition was considered. For infinite bodies, the stress equations contain two parameters, the stress concentration factor Kt and the notch root radius ρ; for finite bodies, a finite size correction factor fw which involves the notch depth, t, and the length of ligament ahead of the notch tip, d, was introduced. After the approximate equations reach their minimum value, a uniform distribution is assumed. The accuracy of this description of the stress field was verified by comparison with analytical solutions and the results of numerical analysis. The new equations give better estimations of stress fields than currently available approximate expressions.
A PROCEDURE TO MINIMISE ERROR IN FATIGUE CRACK GROWTH TESTING
Authors: Oore M.
Published: August 2010

Abstract A concept for minimising the error associated with the K gradient and the interval of crack length measurement in fatigue crack growth testing has been extended to include crack configurations where crack size is significant relative to specimen width. This was used to develop a procedure for deriving the da/dn vs. ΔK relationship from crack growth data. The procedure was applied to several test data, utilizing six measurement points of length vs. cycles data and experimenting with various sizes of crack measurement interval (up to 85% of crack size). The accuracy of the derived da/dn vs. ΔK data was examined by comparison with the baseline data curves. The results were within a few per cent of the actual test data and were usually more accurate than those obtained by secant methods. Increasing the number of data points used in the analysis generally improved the accuracy of the present procedure more than it did with the standard secant method results.
CRITICAL CRACK ASSESSMENT PROCEDURE FOR HIGH PRESSURE STEAM TURBINE ROTORS
Authors: Sedmak A. , Sedmak S.
Published: August 2010

Abstract A critical crack assessment procedure for high pressure steam turbine rotors is introduce and applied. The processes relating to low‐cycle thermal fatigue (LCTF), high‐cycle fatigue (HCF) and creep are considered and the critical crack length is determined in accordance with its shape and position, based on a linear elastic fracture mechanics criterion. Taking this critical crack length as the final value, two mechanisms of crack growth are analysed, LCTF and creep, with the aim of defining the initial value of crack length. Alternatively, LCTF and creep are analysed as crack initiation processes with the aim of defining the appropriate time and number of cycles which can be used in relation to crack growth. The worst‐case materials data are used in order to obtain a conservative estimation of the critical crack length. The procedure is also applicable, directly or modified, to other power plant components, e.g. intermediate and low pressure rotors, steamlines and castings.
A FRACTURE CRITERION FOR CRACKS UNDER MIXED‐MODE LOADING
Authors: Kfouri A. P. , Brown M. W.
Published: August 2010

Abstract A fracture criterion is proposed, based on maximum energy release rates at the tips of short kinks when the main cracks are subjected to mixed mode loading. The criterion differs from existing energy based criteria in that the fracture toughness, gc, is not independent of the stress mode prevailing in the region of the tip of the kink but is a function of the ratio of the mode II to mode I stress intensity factors at the tip of the kink, i.e., gc is determined directionally by an elliptical region with major and minor axes equal to the fracture resistances of the material, KIr and KIIr, for pure mode I and pure mode II, respectively. Points inside the elliptical region are considered safe. When KIIr is equal to KIr the ellipse degenerates into a circle and the fracture criterion reverts to the existing familiar maximum energy release rate criterion based on a single value of the fracture toughness, irrespective of the active mode prevailing in the region at the tip of the kink. In this case, under pure shear (mode II) applied load, KII, the angle of inclination of the fracture crack extension to the main crack, α, is in the region of −76°, in general agreement with previous well established results. However, when the ratio r (=KIIrKIr) is less than r′ (=0.82, approximately) a different pattern emerges and, in particular, under pure mode II load, the crack advance is co‐planar with the main crack, i.e., in mode II. A lower transition value r″ (=0.582, approximately) was also detected under pure mode I applied load. Thus for values of r≥r″, the crack extension is in pure mode I and is co‐planar with the main crack but when r < r″, the crack branches out at an angle (which can be positive or negative) in mixed modes I/II crack extension. Some implications of these results are discussed.
PSEUDO STRESS AND PSEUDO STRAIN BASED APPROACHES TO MULTIAXIAL NOTCH ANALYSIS
Authors: Köttgen V. B. , Barkey M. E. , Socie D. F.
Published: August 2010

Abstract The analysis of notch stresses and strains is one of the key parts of fatigue life prediction of components and structures, In this paper two related approaches are introduced, covering the whole field from uniaxial to multiaxial non‐proportional loading. The pseudo stress at the notch root computed by theory of elasticity is introduced as the governing variable for elastic‐plastic notch analysis. Although the pseudo stress is just a specially defined nominal stress, it eases notch analysis in comparison to using arbitrarily definable nominal stresses, especially for non‐proportional multiaxial loading. Additionally a pseudo strain based approach is introduced and compared to the stress approach. Both proportional and non‐proportional loading are discussed, and compared with the approaches of other workers.
TOUGHNESS GIVEN BY ACCUMULATED WORK IN LEFM: POSSIBLE IMPLICATIONS FOR ELASTOPLASTIC JR“RESISTANCE CURVES”
Authors: Atkins A. G.
Published: August 2010

Abstract J
R vs. Δa curves are often determined from the accumulated work Uacc operated on by an η/Bb factor, and rising JR curves are said to indicate increased resistance to fracture. It seems to have been overlooked, however, that Krafft GR resistance curves in lefm are not obtained in this way from Uacc. Indeed the concept of accumulated work during propagation does not appear in the lefm literature. This paper investigates Uacc in lefm and derives relations for ηUacc/Bb vs. Δa/b for the compact tension and 3‐point notched bend testpieces. For fracture at constant Gc a series of quasi‐linear plots is predicted: all have Gc as their ordinate intercept with slopes which are multiples of Gc, individual values depending on the starting (a/W). Note that ηUacc/Bb does not indicate current toughness directly during globally‐elastic crack propagation; the ordinate values not coinciding with the known toughness Gc (or R, Kc etc) even in cases where there is “real”GR behaviour in the Irwin‐Krafft sense.
DAMAGE HEALING AND STRENGTHENING BEHAVIOUR IN INTELLIGENT MULLITE/SiC CERAMICS
Authors: Chu M. C. , Sato S. , Kobayashi Y. , Ando K.
Published: August 2010

Abstract Fifteen kinds of mullite/SiC samples with different microstructures were prepared in order to examine the effect of Sic volume% and Sic grain size on mullite morphology and mechanical properties. Special attention was paid to the effect of heat‐treatment on fracture stress. It is shown that these materials have damage self‐healing characteristics. The best mullite/SiC system, within the given test conditions, is 20% by volume of Sic, having a grain sue of 0.56 μm, and the best condition for damage healing is a 1 h heat treatment at 1300°C in an air atmosphere.