bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of clinical optic disc assessment with tests of early visual field loss
Authors: Landers John A , Goldberg Ivan , Graham Stuart L
Published: March 2003

Purpose: Clinical optic disc assessment may identify glaucomatous optic neuropathy prior to a patient developing visual field abnormalities on achromatic automated peri­metry (AAP). Tests targeting axons that are selectively damaged or whose redundancy is low, such as short wavelength automated perimetry (SWAP) and frequency doubling perimetry (FDP), may detect visual field loss before it is seen on AAP. This study investigated whether patients in whom characteristic glaucomatous optic disc damage was present without AAP abnormalities had visual field abnormalities with SWAP and FDP.

Methods: A sample of patients (n = 50) with ocular hypertension (normal AAP) were selected, who had SWAP, FDP and stereofundus photography performed. The photographs were then analysed by two glaucoma subspecialists who were masked to the assessments of the other and to the patients’ SWAP and FDP results. A categorization of the optic discs was made as either normal or abnormal and this was compared with their SWAP and FDP findings.

Results: On comparing SWAP and FDP with clinical optic disc assessment as the ‘gold standard’, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 33%, 92%, 57% and 81%, respectively, for SWAP and 25%, 89%, 49% and 79%, respectively, for FDP.

Conclusion: In glaucoma suspects, the study suggests that SWAP and FDP identify subjects with early glaucomatous optic neuropathy missed by AAP.
Pars plana vitrectomy in the management of retained intravitreal lens fragments after cataract surgery
Authors: Kwok Alvin KH , Li Kenneth KW , Lai Timothy YY , Lam Dennis SC
Published: March 2003

Purpose: To assess the outcome of patients who underwent pars plana vitrectomy for retained lens fragments after cataract surgery.

Methods: A retrospective study of all consecutive cases with pars plana vitrectomy performed for retained lens fragment was conducted. Twenty‐seven eyes of 27 patients were included in the study.

Results: Twenty‐four (89.9%) eyes received phacoemulsification. Pars plana vitrectomy was performed at the same sitting, or ranged from day 1−70 after cataract surgery. The mean follow up was 31.1 months. Final visual acuity of 6/12 or better was achieved in 15 (55.6%) patients. After excluding patients with pre‐existing eye diseases, 68.4% of patients had visual acuity 6/12 or better. Complications after pars plana vitrectomy included glaucoma (22.2%), retinal detachment (11.1%) and surgically induced necrotizing scleritis (3.7%).

Conclusion: Ocular complications with poor visual outcome can occur after removal of intravitreal retained lens fragments complicating cataract surgery.
Management of rhegmatogenous retinal detachment without detectable breaks
Authors: Kocaoglan Hülya , Ünlü Nurten , Acar Mehmet A , Sargin Müge , Aslan Bekir S , Duman Sunay
Published: March 2003

Purpose: To evaluate the causes of failure to find retinal breaks, the anatomical and functional outcomes of patients with rhegmatogenous retinal detachment (RD) without detectable breaks (Group I), to compare the results with detectable breaks (Group II).

Methods: Forty‐five out of 258 eyes that had RD without detectable breaks were analysed retrospectively.

Results: The causes of failure to find retinal breaks were aphakia/pseudophakia in 22 eyes, small pupil without any eye disease in four eyes, corneal opacity in two eyes, cataract in two eyes, vitreous haze in two eyes, choroidal detachment in one eye, and unknown cause in 12 eyes. After a single scleral buckling procedure, anatomical re‐attachment of the retina successfully occurred in 62.2% of group I and 78.9% of group II patients. After repeated surgery, final anatomical success rates were 87.2% and 90.2%, respectively. The best corrected visual acuity was 6/60 or better in 53.9% in Group I and 52.5% in Group II.

Conclusion: The main cause of failure to find the retinal break was aphakia or pseudophakia. Although the rates of retinal reattachment in eyes without detectable breaks in primary buckling surgery was lower than detectable breaks and reoperations were required more frequently, final success rates were satisfactory and similar in both groups.
Pneumococcal keratitis: a clinical profile
Authors: Parmar Pragya , Salman Amjad , Kalavathy C Munusamy , Jesudasan CA Nelson , Thomas Philip A
Published: March 2003

Aim: To study the clinical features of pneumococcal keratitis and response to ciprofloxacin therapy.

Methods: A retrospective analysis was undertaken of 58 patients with culture‐proven pneumococcal keratitis seen over a period of 2 years.

Results: Pneumococcal keratitis accounted for 33.3% of bacterial keratitis. Most cases presented with non‐severe keratitis (77.5%). Co‐existing sac pathology was more frequent in pneumococcal ulcers as compared to non‐pneumococcal bacterial ulcers (50%vs 9%, P < 0.001). Characteristic clinical features enabling an accurate clinical diagnosis were found in 27.5% and lanceolate diplococci on Gram's stain were identified in 76% of cases. In vitro testing showed a high susceptibility to cephazolin and ciprofloxacin. All patients received ciprofloxacin as first‐line therapy. Eighty per cent responded well with complete healing of the ulcer. A second drug was required in 8.5%.

Conclusion: Ciprofloxacin therapy can be effective in the treatment of pneumococcal keratitis.
A CASE OF TYPHOID ULCERS FOLLOWED UP WITH COLONOSCOPY
Authors: Kasamaki Shinji , Sato Teruhiko , Ochiai Takumi , Shijo Hiromasa , Kudo Keizo , Suda Sumito
Published: March 2003

A 56‐year‐old man was admitted to the Misato‐Junshin Hospital because of severe melena, fever, and abdominal pain. He had never traveled outside of Japan. Colonoscopic examinations revealed multiple round ulcers extending from the cecum to the proximal transverse colon. Cultures of stools and arterial blood were positive for Salmonella typhi, confirming a diagnosis of typhoid fever. The patient responded to treatment with oral neuquinoron antibiotics, tosufloxacin tosilate.
Successful Endoscopic Band Ligation for Treatment of Postpolypectomy Hemorrhage
Authors: Mizuta Yohei , Yamakawa Masaki , Isomoto Hajime , Takeshima Fuminao , Murase Kunihiko , Irie Jyunji , Kawai Kioko , Murata Ikuo , Kohno Shigeru
Published: March 2003

We describe a case of large pedunculated tubulovillous adenoma of the stomach associated with postpolypectomy hemorrhage, which was successfully treated by endoscopic band ligation. The case study involved a 60‐year‐old Japanese woman with a pedunculated polyp with a slightly lobular surface, measuring 25 mm in diameter. It was detected on the posterior wall of the middle body of the gastric remnant. The lesion was diagnosed as a tubulovillous adenoma by a biopsy specimen and treated by endoscopic polypectomy using the detachable snare to prevent postpolypectomy hemorrhage. There was no episode of immediate postpolypectomy hemorrhage, but hematemesis occured 18 h after the excision. Endoscopic examination of the stomach showed the mark left by bleeding on the cutting surface and the absence of the detachable snare. Endoscopic intervention by rubber band ligation was performed to prevent the recurrent bleeding. Complete hemostasis was obtained and no serious complications occured.
Role of pituitary adenylate cyclase‐activating polypeptide in the growth modulation of human pancreatic carcinoma
Authors: Zhao Min , Sun Lumei , Jiang Ruolan
Published: March 2003

OBJECTIVE: To investigate the role of pituitary adenylate cyclase‐activating polypeptide (PACAP) in the growth modulation of human pancreatic carcinoma and to determine whether sphingomyelin may act as a second messenger in post‐receptor signal transduction.

METHODS: Three human pancreatic cancer cell lines, JF305, HS766T and ASPC‐1, were cultivated, propagated and then treated with various concentrations of PACAP1–38 (10–12–10–6 mol/L). The number of proliferating cancer cells was estimated by using Mosmann’s MTT method. The concentration of intracellular sphingomyelin was determined by thin layer chromatography. Levels of intracellular adenosine monophosphate and Ca2+ were measured by radioimmunoassay and Fura‐2/AM, respectively.

RESULTS: The proliferation of human pancreatic cancer cell lines was enhanced and the intracellular levels of sphingomyelin, cAMP and cytosolic Ca2+ were increased by treatment with PACAP1–38. The effect of PACAP1–38 on JF305, HS766T and ASPC‐1 cells was inhibited by somatostatin.

CONCLUSIONS: It is possible that PACAP1–38 plays a role in the proliferation of human pancreatic cancer cells. The post‐receptor signal transduction of PACAP may be mediated by both the adenosine cyclinase and calcium–calmodulin pathways. Sphingomyelin may be a second messenger involved in this process.
Supine hypertension with transient papilledema
Authors: Igase Michiya , Kohara Katsuhiko , Nomura Takuo , Yamamoto Yoshikuni , Miki Tetsurou
Published: March 2003

A 68‐year‐old male, married, retired public official was admitted to hospital for thorough examination and appropriate treatment of gait disturbance and dizziness. He had been diagnosed with diabetes mellitus and hypertension for at least 28 years, and had been treated with insulin and antihypertensive medications intermittently at another hospital. We identified the major cause of his complaints as orthostatic hypotension, and controlled his casual systolic blood pressure (BP) to within the range of 140–160 mmHg in a sitting position. After a few weeks, on ophthalmic study, right papilledema was diagnosed. There was no progression of visual disturbance nor circulatory impairment in the optic fundi. Based on the results of 24‐h ambulatory BP monitoring, we assumed that his supine systolic hypertension triggered the papilledema, so we controlled his supine systolic BP to within the range of approximately 140–160 mmHg. After 2 weeks of controlled BP the papilledema improved. Visual disturbance was not reported during 1 year of follow up. In case of severe autonomic disorder such as orthostatic hypotension, attention should be paid to changes in the optic fundi, and ophthalmoscopic examination should be performed regularly.
Clinical significance of geriatric sleep apnea syndrome
Authors: Teramoto Shinji , Inoue Yuichi , Ouchi Yasuyoshi
Published: March 2003

The prevalence of sleep apnea syndrome (SAS) is known to increase with advancing age, contributing to excessive daytime sleepiness, cardiovascular dysfunction and the impairment of health‐related quality of life. However SAS is often undiagnosed and overlooked in the elderly. It is important to note that SAS is a differential diagnosis of insomnia, dementia, and depression in the elderly. For an accurate diagnosis of geriatric SAS, the apnea and hypopnea index as measured by polysomnography must be greater than 10 or 15. Many untoward effects of SAS on the health status of the elderly are considered to be clinically significant. Although it has been suggested that geriatric SAS has less effect on the mortality and morbidity of sufferers than does middle‐aged SAS, sleep apnea in any age group, if severe and accompanied by symptoms, should be treated. However, the clinical significance of geriatric SAS should be further elucidated.
Development of a short neuropsychological battery to screen early dementia in the elderly
Authors: Funabiki Yasuko , Takechi Hajime , Akamatsu Tomoko , Kita Toru
Published: March 2003

Background:  The purpose of the present study was to develop a short screening neuropsychological battery for patients with very mild and mild dementia.

Methods:  The participants involved in the present study consisted of 162 persons who were 65 years and older. Fifty‐four of the patients had very mild or mild dementia and had a mini‐mental state examination (MMSE) score of 19 or above. Normal control samples were community‐dwelling volunteers, or persons recruited from outpatients who did not suffer from any cognitive problems. Mini‐mental state examination, the category cued memory test (CCMT) – a modified brief memory test in which category cues were given for both acquisition and retrieval – verbal fluency test (VFT) and clock drawing test (CDT) were carried out. Using logistic regression models, the best battery was selected. The validity and reliability of the battery were also assessed.

Results:  The combination of CCMT, VFT and CDT was the best screening battery and could be accomplished in about 10 min. The battery had a high degree of sensitivity (94.4%), specificity (99.1%), positive and negative predictive values. Test‐retest, interrater and alternate forms reliabilities were substantial using the intraclass correlation coefficient, and all of the P‐values analyzed by the Pearson correlation coefficient were below 0.005.

Conclusions:  This short battery has enough validity, reliability and efficiency to detect early dementia especially in an elderly primary care setting. The CCMT is also a useful memory test even if used alone.
Julian Smith: Scientific surgeon, photographer, inventor
Authors: Vellar Ivo D.
Published: March 2003

Julian Augustus Romaine Smith was one of the surgeons who, in the company of Thomas Dunhill, Hugh Devine, Douglas Shields and David Murray Morton, established Saint Vincent’s Hospital, Melbourne, as arguably the premier surgical hospital in Victoria, if not Australia. Smith abandoned a most promising scientific career to study medicine, completing his medical course in Melbourne where he graduated top of his year in 1898/1899. He gained his MD in 1901 and set up practice in Morwell, a Victorian country town, where he initiated his surgical career. In 1905 Smith returned to Melbourne and worked as assistant to Mr F. D. Bird, a prominent surgeon. He travelled overseas in 1906, visiting leading medical centres in England where Almroth Wright’s work on vaccination made a deep impression on him. On his return to Australia in 1908 he joined the surgical staff at Saint Vincent’s Hospital as surgeon to outpatients, finally retiring as surgeon to inpatients in 1928. Smith was made a Foundation Fellow of the Australasian College of Surgeons in 1927. Smith was regarded by his peers as a brilliant innovative surgeon with a special interest in urology. He became an expert cystoscopist. After he retired, he continued his long‐standing interest in portrait photography for which he was considered a master. During World War II he designed and built an elegant roller pump for use in direct blood transfusion. He died in 1947, survived by his wife, a daughter and three sons, one of whom became President of the Royal Australasian College of Surgeons.
Simplified technique for laparoscopic appendectomy
Authors: Motson Roger W. , Kelly Michael D.
Published: March 2003

In this article, a simplified technique for laparoscopic appendectomy is described in which the base of the appendix is firstly divided, and then ligated with an endoloop. An endoloop is then passed over the appendix onto the mesoappendix and tightened to secure the blood supply. The appendix can then be freed and removed. This technique has been used by the authors in difficult cases, and has produced excellent results.
Tube sigmoidostomy: A modification of the antegrade colonic evacuation
Authors: Whineray Kelly Erica , Bowkett Brendon
Published: March 2003

Background:  The Malone appendicostomy enema has established its place in the treatment of paediatric faecal incontinence. More recently, the laparoscopic appendicostomy enema has gained favour. In the situation where the appendix has already been removed, caecal stomal tubes can be constructed to facilitate antegrade colonic wash‐outs. These techniques may not provide an accept­able result if there is a significant time delay from the introduction of the enema to the result. Wash‐outs through the more distal colon − either by retrograde techniques with a rectal tube or, more recently, through a plastic stomal device inserted percutaneously into the sigmoid colon (the Chait tube) − can result in rapid evacuation. Rectal wash‐outs may not provide an adequate lavage and can be technically difficult for some children to perform, while many other children find external devices cosmetically unacceptable. We present a modification of this distal colonic technique that can allow greater control, can be used in the absence of an appendix and avoids the need for an external device.

Methods:  Two paediatric patients with spina bifida and faecal incontinence underwent tube sigmoidostomy formation. In both patients, the appendix was not available to be used for colonic wash‐outs.

Results:  Both patients reported excellent success with this procedure. They are continent, able to cannulate the stoma and irrigate independently.

Conclusions:  The technique can provide excellent continence control in patients who are not successful with a right‐sided Malone appendicostomy. It also overcomes the need for a catheterizable appendix, and an external device.
Targeting molecular mechanisms in cancer
Authors: Balleine Rosemary L. , Kefford Richard F.
Published: March 2003

Malignant disease is characterized by the disregulated growth of transformed cells. In recent years, dramatic insight into the molecular mechanisms of this phenomenon have come from basic cancer research. Detailed knowledge of the molecular pathology of cancer allows therapeutic agents to be designed that specifically target aberrant cellular processes. There are currently a number of targeted treatment strategies being evaluated. In the future, it is likely that this mechanistic approach will have a significant impact on clinical oncologyand the diagnostic evaluation of tumours.
Use of red blood cell transfusions in surgery
Authors: Maxwell Ellen L. , Metz Jack , Haeusler Michael N. , Savoia Helen F.
Published: March 2003

Background:  Limited blood supplies necessitate the rational use of blood products. The aim of the present study was to provide a basis for audits of red cell usage in surgery by benchmarking common practice. Application of the data to the construction of a maximum surgical blood order schedule may be relevant for centres that perform a serological crossmatch or who collect autologous units.

Methods:  Data on surgical procedures identified by Commonwealth Medical Benefits Schedule item numbers, were collected retro­spectively from theatre and blood bank records at the Royal Melbourne and Melbourne Private hospitals from May 1997 to April 1998. The percentage of procedures for which red cells were transfused, and the mean, median and range of units transfused for procedures with ≥ 30% transfusion likelihood were identified.

Results:  Over 12 months, 266 surgical procedure codes were itemized ≥ 10 times each, contributing 12 300 data entries. Only 38 procedures demonstrated an incidence of transfusion of at least 30%. Most frequently transfused procedures included spinal fusion, total hip replacement, mandible/maxilla resection, prostatectomy and bladder excision.

Conclusion:  The number of common surgical procedures in which there is a 30% or greater likelihood that red cell transfusions will be given is limited. This benchmarking of common red cell usage is a first step in the process of determination of transfusion appropriateness.
Abdominal aortic aneurysm repair in the veteran population
Authors: Kruger Allan , Foster Wallace , Love Arthur , Woodruff Peter , Blackford John
Published: March 2003

Background:  The aim of this study was to audit the outcome of elective open aortic aneurysm repair in a veteran hospital to determine whether age ≥80 years influenced the morbidity or mortality.

Methods:  All elective abdominal aortic aneurysm (AAA) repaired at Greenslopes Private (Repatriation) Hospital between January 1995 and July 2000 were reviewed. Operative details, premorbid condition, postoperative outcomes as well as length of admission were recorded. Patients were grouped according to age as ≥80 years or <80 years.

Results:  There were 251 open elective AAA (including infrarenal and suprarenal, as well as recurrent AAA) repairs carried out during this period, 64 of which were patients of age ≥80 years. Cardiovascular risks factors did not differ between groups nor did complication rates for patients ≥80 and <80 years of age (19.1 and 19.8%, respectively). Mortality rates were not significantly different between groups (≥80 years: 6.25%; <80 years: 4.8%; P > 0.6).

Conclusions:  Age ≥80 years should not be an exclusion criteria when contemplating open elective AAA repair.
Use of adjuvant, preoperative chemo‐radiotherapy in patients with locally advanced rectal cancer
Authors: Platell Cameron , Cassidy Barry , Heywood Janelle , Claringbold Phillip
Published: March 2003

Background:  The objective of this study was to perform a non‐randomised prospective examination of the efficacy of adjuvant, preoperative chemo‐radiotherapy in patients with locally advanced rectal cancer.

Methods:  Between 1996 and 2001, patients presenting with biopsy‐proven, locally advanced, rectal cancers within 12 cm of the anal verge were referred for a long course of adjuvant chemo‐radiotherapy prior to their surgery. Locally advanced lesions were defined by either: (i) endoanal ultrasound showing at least full thickness penetration of the rectal wall (i.e. T3, T4); (ii) abdominal computed tomography scan showing infiltration of adjacent structures, or; (iii) clinical examination demonstrating a fixed lesion. All patients were followed through the hospital colorectal unit. A Kaplan−Meier survival analysis was used to determine survival and local recurrence rates.

Results:  There were 60 patients with a mean age of 61.5 years (range 33−77 years) with a sex distribution of males to females of 1.7−1.0. Curative resections were performed in 81% of these patients. The remainder (n
= 12) were found to have either metastatic disease at operation (n
= 5), inoperable disease (n
= 2), or had positive resection margins on histology (n = 7). The mean follow up was 2.1 years (maximum 5.1 years). The overall 2‐year survival rate was 86.1% (95% CI ±5.4%). In patients undergoing curative resections, the overall 2‐year survival rate was 91.4% (95% CI ±4.8%), and the 2‐year disease free survival rate was 85.1% (95% CI ±6.2%). The 2‐year local recurrence rate was 7.5%.

Conclusions:  The use of adjuvant, preoperative, chemo‐radiotherapy in patients with locally advanced rectal cancer is associated with high short‐term survival and a low recurrence rate.
New technique to assess the axilla for breast cancer metastases using cell separation technology
Authors: Edwards Meredith , Twin Jane , Wilkinson Stephen
Published: March 2003

Introduction:  Accurate staging of the axilla for metastatic disease is critical in deciding on the optimal management of patients with breast cancer. Lymph node status is the most powerful prognostic factor. Current standard surgical management of breast cancer involves axillary dissection for staging. Pathological staging by routine histology, however, is known to understage the disease extent because only one or two sections are taken from each node, a sampling of less than 1% of most nodes. Sentinel node biopsy is currently under trial to determine if thorough pathological staging of the most likely involved node is more accurate than standard pathological assessment of all nodes. The present pilot study was undertaken to investigate an alternative method of assessing all axillary nodes for cancer cells.

Methods:  After routine material was taken from lymph nodes for standard pathological assessment, discarded parts of nodes were used for the study technique. These node parts were mechanically disaggregated, and the cell suspension centrifuged on a density gradient to separate any tumour cells (into the pellet) from lymphocytes (at the top of the gradient). The pellet was then assessed by haematoxylin and eosin and immunohistochemistry.

Results:  The results of the present study proved highly significant. The technique detected metastatic cells in three nodes which were negative on routine pathology, in one case changing the status of the patient from node‐negative to node‐positive.

Discussion:  It is concluded that the technique examined in the present paper has the potential to reduce sampling error, may offer far more accurate axillary staging than routine histopathology, and should be further evaluated in a controlled trial.
Surgical management of ductal carcinoma in situ in Australia in 1995
Authors: Shugg Dace , White Victoria M. , Kitchen Paul R. B. , Pruden Myee , Collins John P. , Hill David J.
Published: March 2003

Background:  In the present paper we describe the presentation and management of ductal carcinoma in situ (DCIS) of the breast in women in Australia in 1995. This representative, national data set provides a historical comparator for studies examining DCIS management that follow.

Methods:  Surgeons identified by population‐based cancer registries as having treated a new diagnosis of DCIS between 1 April and 30 September 1995 completed a questionnaire on the presentation and management of each case.

Results:  Two hundred and five surgeons supplied treatment details on 418 DCIS tumours in 415 women. Half of all tumours were detected at BreastScreen clinics and a further 25% were detected at other mammography centres. Twenty‐six percent of tumours were palpable at presentation, 33% were multifocal and 55% were high grade (including comedocarcinoma). Breast conserving therapy (BCT) rather than mastectomy was utilized in 260 (62%) of cases. Tumours that were of low grade, small in size and not multifocal were more likely to be treated by BCT. Surgeons seeing six or more DCIS cases in the 6‐month period were more likely to utilize BCT. Of the conservatively treated cases, 22% were referred for a radiation oncology consultation. The most common reasons for treating DCIS with mastectomy were that the tumour was too extensive or multifocal (63%), it extended to margins of the specimen (42%), or patient concerns about recurrence (34%).

Conclusions:  In 1995 the majority of DCIS was treated with breast conserving surgery alone. Surgeons treating more DCIS cases were more likely to perform conservative surgery than surgeons treating only one DCIS case in the study period.
Current evidence does not support routine adjuvant radiotherapy for rectal cancer
Authors: Meagher Alan P. , Ward Robyn L.
Published: March 2003

Background:  There is widespread support in the published literature for routine adjuvant radiotherapy for rectal cancer.

Methods:  In the present paper, the current evidence regarding adjuvant radiotherapy is reviewed, particularly the most recent studies of preoperative radiotherapy (usually including patients with Stage I, II and III disease) and postoperative radiotherapy (usually for Stage II and III disease), and meta‐analyses. Two questions in particular are addressed: Does radiotherapy improve survival when surgeons are able to achieve low local recurrence rates with surgery alone? Does radiotherapy improve patients’ quality of life?

Results:  Radiotherapy has only been demonstrated to significantly improve survival in one individual study and one recent meta‐analysis. The local recurrence rates in the no‐radiotherapy arm of these studies were 27% and 21−36.5%, respectively. In more recent studies, with lower local recurrence rates reflecting modern surgical standards, no survival advantage has been found. It is currently unknown whether radiotherapy improves patients’ quality of life. Studies have demonstrated that radiotherapy has acute and long‐term detrimental effects on quality of life. While local recurrence can be very debilitating, it can also be asymptomatic, and the overall effect of the local recurrence statistics found in adjuvant therapy studies on quality of life has not been systematically investigated. The most recent studies demonstrate that 17−20 patients need to undergo adjuvant radiotherapy to prevent one local recurrence.

Conclusion:  Current evidence does not support the widespread advocacy for routine adjuvant radiotherapy as used in the treatment arms of recent trials.
Audits, errors and the misplace of clinical indicators: Revisiting the Quality in Australian Health Care Study
Authors: Siddins Mark
Published: March 2003

Publication of the Quality in Australian Health Care Study in 1995 represented a defining moment for Australian health care providers. The high incidence and cost of preventable adverse events underscored a need for defined process, error recognition and audit cycle. Despite this, surgical audit has continued to emphasize clinical indicators relevant to technical performance. The greatest burden of preventable error can be traced to deficiencies in the process by which management expectations are supported. Recog­nizing this, the focus of clinical audit must be expanded. In particular, outcome assessment should be routine rather than sporadic, and should broadly encompass safety, effectiveness and efficiency. Devolving this responsibility to paraclinical groups is in itself insuf­ficient. Quality and safety cannot be adequately addressed unless surgeons actively participate in audit cycle. Failure to meet this challenge in a transparent and timely manner potentially undermines the future of professional autonomy.
Initial experience with cultured epithelial autografts in massively burnt patients
Authors: Elliott Michael , Vandervord John
Published: March 2003

Background:  Prognosis in patients with severe burns is improved by early debridement and coverage with skin. The limiting factor in these patients is the lack of unburnt skin for harvesting. Cultured epithelial autograft (CEA) sheets provide an alternative means of covering debrided skin. This is a report on an initial experience with using CEA sheets.

Methods:  The two patients in this study had their medical records examined retrospectively.

Results:  The effective take of the CEA sheets was zero in both patients. One of the patients died approximately 6 weeks after admission.

Conclusions:  Because of the poor graft take seen in the patients in the present study, the use of CEA sheets only as a form of temporary biological dressing is recommended.
CONSIDERATIONS OF THE EFFECT OF RESIDUAL STRESSES ON FATIGUE OF WELDED ALUMINIUM ALLOY STRUCTURES
Authors: Berkovits A , Kelly DW , Di S
Published: March 2003

A new class of large, high‐speed seagoing ferry‐boat is under development for service around the world. The ships, which are built entirely of aluminium‐alloy plate and stiffeners, show a propensity for fatigue cracking of the welded structure. Cracks may occur in both the hulls and the superstructure early in their 20‐year service life. Early appearance of fatigue cracks is shown to result from the combined stress and strain fields set up in weld zones by the static residual stresses and cyclic loads, beyond the effects of weld and detail geometry. A numerical example demonstrates that conventional methods of fatigue analysis overestimate the lifetime of the welded aluminium structure, while damage tolerance analysis based on fracture mechanics leads to improved prediction.
DELAMINATION: LAMINATE ANALYSIS AND FRACTURE MECHANICS
Authors: Yin
Published: March 2003

In the analysis of a multilayered composite laminate with an arbitrarily shaped delamination, accurate non‐linear laminate analysis is required to obtain the kinematic and kinetic variables which characterize the local state of deformation at a generic point of the delamination front. These variables provide the strain/curvature parameters and the boundary tractions for the local analysis model of a multimaterial region containing an interfacial crack. The singular elasticity solution in the vicinity of the crack tip is obtained by an eigenfunction expansion, where the coefficients of the eigenfunctions are evaluated by boundary collocation. The accuracy of the present solution is indicated by the computed energy release rate, which is in close agreement with the result based on path‐independent integrals.
REPRESENTATION OF CYCLIC PROPERTIES OF AUSTENITIC STEELS WITH PLASTICITY‐INDUCED MARTENSITIC TRANSFORMATION
Authors: Kaleta J , Zie G
Published: March 2003

This study is part of a wider research project on the cyclic properties, energy cumulation and fatigue life of metastable austenitic steels undergoing a martensitic transformation induced by plastic straining.

This paper considers the representation of the σ–ε hysteresis loop over a wide range of strain. A novel, power‐function model of cyclic elastic–plastic material behaviour was used. The model allows the occurrence of a cyclic yield point and the characteristic inflection point of the CSS curve, which separates the single‐phase (austenite) region from the two‐phase (austenite + martensite) one. The plastic strain corresponding to the inflection point is assumed to be a material constant and is termed the martensitic transformation cyclic limit ε1 . The generalization of the model made possible the representation of cyclic softening of the two‐phase material.

In addition, the study chose a measurement technique that assisted the estimation of the cyclic plastic strain (ε1 ) inducing the martensitic transformation. The crossed magnetomechanical (Villari) effect was shown to be applicable in detecting the nucleation and estimating the increase of the α′‐martensite content.

The identification was performed making use of experimental results obtained from an AISI 304 high nickel content steel. The tests were performed under both increasing and constant plastic strain amplitude. The measured quantities were: total strain εt elastic strain εe , plastic strain εp , stress σ and hysteresis loop area ΔW. The results justify the assumed model.
MODAL APPROACH FOR PROCESSING ONE‐ AND THREE‐POINT BEND TEST DATA FOR DSIF‐TIME DIAGRAM DETERMINATION PART I—THEORY
Authors: Rokach IV
Published: March 2003

A hybrid experimental/numerical method for the determination of the variation in the dynamic stress intensity factor (DSIF) with time during one‐ or three‐point bend impact tests is presented. According to the concept of hybrid methods, a DSIF–time diagram is calculated for a particular mathematical model for the specimen using experimentally registered loading as the model excitation. The simple expression for the impact DSIF–response function is derived for an arbitrary linear model of the specimen, using the modal superposition method. Finally, formulae for DSIF calculations for different types of loading approximation are derived.
CYCLIC DEFORMATION OF A DIRECTIONALLY SOLIDIFIED COBALT‐BASE SUPERALLOY
Authors: Zheng  , Lu  , Yongbo  , Zhuangqi
Published: March 2003

An investigation has been carried out on the cyclic deformation and changes in microstructure of a directionally solidified cobalt‐base superalloy. The tests are conducted at 700 °C and 850 °C in air under different total strain amplitudes. The alloy tested at 700 °C exhibits an initial hardening, a short saturation stage and an evident secondary hardening, while the alloy at 850 °C suffers continuous cyclic hardening until fracture. TEM examinations indicate that the initial hardening of the alloy at 700 °C is caused by the pile‐ups of dislocations and stacking faults at the stacking fault intersections, while the stress saturation is due to the weakening of obstacles against the dislocation movement. The secondary hardening has a contribution from the formation of sessile dislocation tangles. The early stage of continuous hardening of the alloy at 850 °C is related to the pile‐ups of dislocations and stacking faults at the intersections, and the later stage is controlled by the interaction between precipitates and dislocations.
THE FATIGUE BEHAVIOUR OF METAL–MATRIX COMPOSITES UNDER SINGLE OVERLOADS
Authors: Rodopoulos  , Yates
Published: March 2003

The fatigue crack growth response of Ti‐based metal–matrix composites (MMCs) under single overloads was investigated. Extensive debonding and failure of bridging fibres were confirmed to be the major controlling mechanisms accelerating crack growth after peak overloads. Numerical predictions show that the fatigue damage severity is increased when the overload is applied at shorter crack lengths. Finally, extensive debonding and failure of bridging fibres was corroborated with a fatigue damage map to provide design guidelines.
IMPROVING THE FATIGUE CRACK RESISTANCE OF WASPALOY BY SHOT PEENING
Authors: Turnbull  , De Los Rios  , Tait  , Laurant  , Boabaid
Published: March 2003

Four‐point bending fatigue tests were conducted to study the effect of shot peening on the fatigue life of the nickel‐base superalloy, Waspaloy. The influence of shot peening intensity on crack initiation, Stage I crack growth and the Stage I‐to‐Stage II crack growth transition phases, has been examined to identify the mechanisms by which shot peening improves fatigue resistance. The potential for extending the fatigue life of fatigue‐damaged Waspaloy components has been explored by shot peening specimens which had been cyclic damaged to various degrees. The fatigue test was then continued after peening to ascertain the possibility of crack arrest or extending fatigue life. These experiments explore the possibility of ‘healing’ fatigue damage by a surface engineering treatment.
CORROSION FATIGUE FRACTURE BEHAVIOUR OF A SiC WHISKER–ALUMINIUM MATRIX COMPOSITE UNDER COMBINED TENSION–TORSION LOADING
Authors: Minoshima  , Nagashima  , Komai
Published: March 2003

We describe an investigation into the fatigue fracture behaviour under combined tension–torsion loading of a SiC whisker‐reinforced A6061 aluminium alloy fabricated by a squeeze casting process. Special attention was paid to the environmental effects on fatigue fracture behaviour. Tests were conducted on both the composite and its unreinforced matrix material, A6061‐T6, under load‐controlled conditions with a constant value of the combined stress ratio, α = τmax /σmax in laboratory air or in a 3.5% NaCl solution at the free corrosion potential. The corrosion fatigue strength of both the matrix and composite was less in the solution than in air. The dominating mechanical factor that determined the fatigue strength in air was either the maximum principal stress or the von Mises‐type equivalent stress, depending on the combined stress ratio. However, in the 3.5% NaCl solution, the corrosion fatigue strength of both materials was determined by the maximum principal stress, irrespective of the combined stress ratio. In the case of the matrix material, crack initiation occurred by a brittle facet normal to the principal stress due to hydrogen embrittlement. However, in the composite material, the crack was initiated not at the brittle facet, but at a corrosion pit formed on the specimen surface. At the bottom of the pit, a crack normal to the principal stress was nucleated and propagated, resulting in final failure. Pitting corrosion was nucleated at an early stage of fatigue life, i.e. about 1% of total fatigue life. However, crack initiation at the bottom of a pit was close to the terminal stage, i.e. about 70% or more of total fatigue life. The dominating factor which determined crack initiation at a pit was the Mode I stress intensity factor obtained by assuming the pit to be a sharp crack. Initiation and propagation due to pitting corrosion and crack growth were closely examined, and the fatigue fracture mechanisms and influence of the 3.5% NaCl solution on fatigue strength of the composite and matrix under combined tension–torsion loading were examined in detail.
FATIGUE SPECIMENS FOR SHEET AND PLATE MATERIAL
Authors: Schijve J
Published: March 2003

The usefulness of simple sheet and plate specimens is discussed for various experimental research purposes. Specimens should be representative, as much as possible, of the conditions of fatigue problems in practice, which is more difficult to achieve for the fatigue crack initiation phase than for macro‐crack growth. In many cases, small specimens can not be recommended because of insufficient similarity to the conditions of the engineering structure. Larger specimens have advantages for measurements of crack length and crack closure. The compact tension specimen and a recently proposed derivative are asymmetric specimens, while the middle crack specimen, central notch specimen and double‐edge notch specimen are symmetric. The latter specimens should be preferred for experimental reasons as well as for reasons of a better similarity to the conditions of practical fatigue problems. A significant disadvantage of the asymmetric specimens is the high gradient of the stress intensity factor (dK/da).
The crack‐modelling technique: optimization of parameters
Authors: Taylor D. , Carr A. K.
Published: March 2003

The crack‐modelling technique is a method for prediction of fatigue in components using finite element (FE) analysis. The technique, which is based on the estimation of equivalent K factors for stress‐concentrators, has had some initial success in analysing components of complex shape, but this has raised a number of questions about the potential accuracy of the method and its sensitivity to the choice of operating parameters. The present paper reports on a systematic study using four different specimen types and one component geometry. Accurate estimates of equivalent K values are shown to be possible for both sharp notches and blunt notches, loaded in uniaxial tension or bending, using a very simple approach in which the stress distribution from the notch is compared to that from a standard cracked body. The method shows some sensitivity to the optimization routines used, and to some extent to the choice of the standard cracked body. It is relatively insensitive to mesh refinement and can be used with simple, elastic FE models.
Fracture modelling of WC‐Co hardmetals using crystal plasticity theory and the Gurson model
Authors: Connolly P. , McHugh P.E.
Published: March 2003

The behaviour of edge cracks under Mode I loading in the WC–Co material system is studied using the finite element method (FEM). This work focuses on ductile failure mechanisms in the Co binder. A micromechanical approach is taken whereby Co layers are modelled explicitly. An embedding technique is employed. Crystal plasticity theory and J2 flow theory are used to represent plastic deformation in Co ligaments. Areas of high hydrostatic stress, triaxiality and accumulated slip or effective plastic strain are identified within the binder material. The Gurson model is used to model crack growth in the Co ligaments. Fracture resistance curves are obtained giving a relationship between macroscopic material behaviour and microscopic failure mechanisms. Factors effecting the crack growth in single and multiple ligaments are identified.
A note on the limit load of welded joints of a rectangular cross‐section
Authors: Alexandrov S.
Published: March 2003

A flat layer of a rigid perfectly plastic material subjected to tension between two rigid blocks is considered. The layer is assumed to have a rectangular cross‐section. The influence of the ratio of the in‐plane layer dimensions on the limit load and the maximum tensile stress is studied. Comparison with numerical calculations of the limit load based on the assumption of the plane strain conditions is made.
A normalization of corrosion fatigue behaviour: an example using an offshore structural steel in chloride environments
Authors: Angelova D. , Akid R.
Published: March 2003

A normalized presentation of the metal fatigue process is proposed and applied to the corrosion fatigue behaviour of an offshore structural steel under different loading conditions. Corrosion fatigue development in this steel under different stress levels and frequencies is presented in both ‘normal’ and ‘normalized’ terms. Experimental results on pitting and corrosion fatigue‐crack growth are used to introduce the new normalized presentation approach, which may be employed to illustrate the corrosion fatigue behaviour of any given metal/environment system. This allows a description of the initiation and growth of defects to be made, involving both time‐dependent and cycle‐dependent stages. It is suggested that a set of dependencies between fatigue‐characterizing parameters may be presented in graphic form and used as a ‘fatigue certificate’ for any given metal/environment system.
An investigation into the location of crack initiation sites in alumina, polycarbonate and mild steel
Authors: Tsuji  , Iwase  , Ando
Published: March 2003

The effects of notch root radius on fracture toughness and crack initiation sites have been investigated in this paper using three different classes of materials. Data on alumina which represent ceramics, mild steel from the metals ffeily and polycarbonate representing plastics were obtained and analysed. The locations of crack initiation sites have been pinpointed by scanning electron microscopy. These identified sites more or less are located within the critical process zone or the theoretical plastic zone. The critical process zone size (Dc ) or the theoretical plastic zone size (RYF ) are independent of the notch root radius unlike the plain‐strain fracture toughness of notched specimens [KIC (ρ)]. The authors emphasize why the parameters Dc and RYF are useful for a quantitative evaluation of the reliability of structural materials.
High‐cycle fatigue of Ti–6Al–4V
Authors: Ritchie  , Davidson  , Boyce  , Campbell  , Roder
Published: March 2003

The definition of the critical levels of microstructural damage that can lead to the propagation of fatigue cracks under high‐cycle fatigue loading conditions is a major concern with respect to the structural integrity of turbine‐engine components in military aircraft. The extremely high cyclic frequencies characteristic of in‐flight loading spectra, coupled with the presence of small cracks resulting from fretting or foreign object damage (FOD), necessitate that a defect‐tolerant design approach be based on a crack‐propagation threshold. The present study is focused on characterizing such near‐threshold fatigue‐crack propagation behaviour in a Ti–6Al–4V blade alloy (with ~60% primary α in a matrix of lamellar α + β), at high frequencies (20–1500 Hz) and load ratios (0.1–0.95) in both ambient temperature air and vacuum environments. Results indicate that ‘worst‐case’ thresholds, measured on large cracks, may be used as a practical lower bound to describe the onset of naturally initiated small‐crack growth and the initiation and early growth of small cracks emanating from sites of simulated FOD.
Fatigue crack growth in a structural steel under single and multiple periodic overload cycles
Authors: Skorupa M. , Schijve J. , Skorupa A. , Machniewicz T.
Published: March 2003

Preliminary results of a research program on fatigue crack growth in a low‐carbon steel under a variable amplitude loading are presented. First, test results are reported on crack growth under simple loading sequences containing single and multiple tensile overloads applied periodically between smaller, constant amplitude cycles. Next, the observed crack growth behaviour is compared to predictions from a theoretical model developed by the authors.