bluuebunny/crossref_metadata_2025 huggingface dataset:
An evidence based medicine approach to determining the adequacy of peritoneal dialysis
Authors: CHURCHILL DAVID N
Published: April 2007

Summary: The most frequently used estimates of adequacy of peritoneal dialysis are Kt/V for urea and creatinine clearance (CCr) expressed as the sum of residual renal and peritoneal clearance. the assumption that renal and peritoneal clearances are equivalent is unproven. Theoretical constructs suggest that a weekly Kt/V of 2.0–2.25 represents adequate dialysis while clinical experience supports a weekly CCr of 40–50L per week. Prospective cohort studies using univariate analysis report better patient survival with weekly Kt/V >1.89. Composite indices show an association of good outcome with weekly Kt/V values of 2.3 and poor outcomes with values of 1.5–1.6. A multicentre prospective cohort study in North America used a multivariate analysis to demonstrate an independent statistically significant association between adequacy of dialysis and patient survival. A 0.1 unit decrease in weekly Kt/V was associated with a 5% increase in the relative risk of death; a 5L/1.73m2 per week decrease in CCr was associated with a 7% increase in the relative risk of death. Over the range of 1.5‐2.3 in weekly Kt/V and 40–95 L/1.73m2 per week in CCr, there was no plateau effect on patient survival. Optimum dialysis, occurring when the incremental clinical gain from increased dialysis dose is not considered worth the increased patient effort or cost, has not been defined. Strategies to achieve adequate dialysis include an earlier initiation of dialysis, use of optimal dialysate volumes and prescription according to membrane transport characteristics.
New peritoneal dialysis solutions
Authors: GOKAL R
Published: April 2007

Summary: Current peritoneal dialysis solutions are not biocompatible, particularly in respect to low pH, high osmolality and use of lactate. In addition, glucose is not an ideal osmotic agent. Recent advances in the formulation of peritoneal dialysis fluids aim to provide a more physiological environment to preserve membrane integrity. the effects of pH and lactate have been overcome by the use of bicarbonate based solutions whilst icodextrin (glucose polymers) often prolonged ultrafiltration in spite of being isomotic to uraemic plasma. Future formulations will see a combination of osmotic agents (including amino acids) and bicarbonate to achieve a more biocompatible solution whilst still meeting the ultrafiltration needs of the patients. Additives (glycosaminoglycans, procysteine) may protect the peritoneum from free radical injury.
Optimalization of erythropoietin administration: an Asian perspective
Authors: LUI SIU FAI
Published: April 2007

Summary: The efficacy and benefits of recombinant human erythropoietin (r‐HuEPO) in the treatment of renal anaemia are well established. Because r‐HuEPO therapy is expensive, it is important to optimize its use. It is acceptable to start with a moderate dosage and aim for a moderate rate of response in order to avoid side effects and to reduce costs. the optimal haemoglobin level should be around 12 g/dL; however, in practice, this is often limited to 10 g/dL. Response rate should be around 1 g/dL per month. Subcutaneous administration is the most optimal route and it can be given once or twice weekly.
Guidelines for writing a scientific paper: an address to beginners
Authors: KLAHR SAULO
Published: April 2007

Summary: Although writing a publishable scientific paper does not require extraordinary writing talent, it does require adherence to a few basic principles. First, choosing a forum for publication is important, since books and journals tend to be highly specialized. Second, following the instructions to authors for that publication is mandatory, and reading those instructions before even beginning the manuscript is advisable. Third, writing the abstract or summary requires a painstaking distillation of background, methods, and results; one should recognize that this is the only part of the work that most readers will ever see. Fourth, the other components of the typical scientific paper: introduction, methods, results, and discussion should constitute an appropriate expansion of the abstract. Results in particular are crucial and should be presented in terms of a few specific findings logically supported by selected data, with details presented in tables and figures that are themselves cogent and easy to follow. Fifth, the writer should review the paper carefully, eliminating all wordiness and clarifying statements that are not as meaningful as they could be. (Writers not proficient in English should ask a colleague to do this.) Following these principles will not guarantee publication, but will guarantee serious consideration of the submission.
Age‐related modification of serum sickness nephritis in the rat
Authors: KOMIYAMA Yuichi , YAMAMOTO Masatoshi , NAKAZAWA Koh , ITOH Nobuo
Published: April 2007

Summary: Serum sickness nephritis was induced in young (3 weeks old) and old (50 weeks old) Fischer rats by immunization with egg albumin, and the age‐related clinicopathological differences were analyzed. At least four differences were recognized between the young and old nephritis rats. First, the induced proteinuria was transient in the young group, but persistent in the old group and second, intramembranous electron dense deposits (IMEDD) in the thickened glomerular basement membrane were characteristic in the old group by electron microscopic observation. Third, the peripheral distribution of immune complexes in glomemlus was much more dominant in the young group. Fourth, the accumulation of monocytes was more prominent in the young group. These findings support the following suggestions: (i) in the ageing rats, there may be lowered efficiency of turnover of the extracellular matrix and the decreased ability of the mononuclear phagocyte system function; (ii) these changes may be responsible for the delayed clearance of the immune complexes from the glomerulus, and (iii) the longstanding presence of IMEDD observed in the ageing rats may play a role in persistent proteinuria.
Correlation of enhanced cell proliferation with decreased density of vitamin D receptor in parathyroid hyperplasia in chronic dialysis patients
Authors: KOIKE Taro , FUKUDA Naoko , FUKAGAWA Masafumi , OHTA Kazuo , KUROKAWA Kiyoshi
Published: April 2007

Summary: The decreased density of the vitamin D receptor (VDR) plays an important role in the pathogenesis and progression of parathyroid hyperplasia in renal failure. In chronic dialysis patients, VDR density is less in nodular hyperplasia than in diffuse hyperplasia and the difference of cell proliferation has been also suggested by DNA analysis. to prove a more direct correlation between VDR density and cell proliferation, VDR density and proliferating cell nuclear antigen (PCNA) were detected in situ by immunohistochemistry in serial sections of surgically excised parathyroid glands from 10 chronic dialysis patients. Among 28 excised glands, 20 glands were nodular hyperplasia and eight glands were diffuse hyperplasia. Vitamin D receptor positive cells were much fewer in nodular hyperplasia (13.1 ± 4.8%) than in diffuse hyperplasia (383 ± 5.6%). In contrast, mean PCNA positive cell numbers per one 400 x field were much higher in nodular hyperplasia (2.0± 1.2) than in diffuse hyperplasia (0.1±0.2). These two parameters, simultaneously detected in the same area of the serial sections, showed strong negative correlation (r= ‐0.719, P<0.0001). Remarkable differences in VDR and PCNA were evident between nodules and the surrounding diffuse hyperplasia in the same section. These data suggest more direct relationship between the decrease of VDR density and parathyroid cell proliferation in chronic renal failure as a pathophysiological mechanism.
Renal tubular calcification in six nephrotic children with acute renal insufficiency
Authors: KANO Kenichi , UEDA Yoshihiko , KYO Keisho , ITO Sachio , ANDO Tamotsu
Published: April 2007

Summary: A review of 42 primary nephrotic children who underwent kidney biopsies found that six patients had calcification of the renal tubules (aged 2‐9 years). These six patients showed significant increases in weight gain, blood pressure, urinary protein, serum urea nitrogen and urinary calcium/creatinine, and significant decreases in serum phosphate, % tubular reabsorption of phosphate and creatinine clearance as compared with 36 nephrotic patients without tubular calcification. Furthermore, these patients received high dose furosemide, and five of six patients received methylprednisolone pulse therapy to treat progressive renal dysfunction. the interval before the first kidney biopsy and after both the onset of the nephrotic syndrome, and the start of glucocorticoid therapy, including methylprednisolone pulse therapy and furosemide, ranged from 1 to 5 months excluding one patient (33 months). Although one patient received haemodialysis, renal insufficiency was resolved from 10 to 18 days after its onset. Glucocorticoid therapy, including methylprednisolone pulse therapy and high dose furosemide in primary nephrotic children with acute renal insufficiency, induced calcification of the renal tubules.
Aluminium accumulation in chronic renal failure affects erythropoiesis
Authors: NESSE Alcira , GARBOSSA Graciela , STRIPEIKIS Jorge , GÁLVEZ Gladys , CASTRO María E , RIZZO Norma , LAURICELLA Ana M , GUTNISKY Abraham
Published: April 2007

Summary: Aluminium (Al) toxicity has been associated with anaemia in exposed patients with chronic renal failure (CRF). the present study was undertaken to determine whether the ingestion of Al citrate was able to affect erythropoiesis in rats with normal or impaired renal function. the renal insufficiency was induced by surgical procedures and control rats were sham operated. Twenty‐four rats were allocated to four groups of six rats each: (A) Sham; (B) Sham+Al; (C) CRF; and (D) CRF+Al. the groups B and D received daily doses of Al citrate (0.5 μmol/g bodyweight) and the groups A and C, deionized water, via the intragastric route. At the end of the experimental period (15 weeks) cultures of late erythroid progenitor cells (CFU‐E) stimulated with erythropoietin were performed and haematological parameters determined. the liver, kidney, brain, bone and serum Al amounts were quantified. the results are expressed as median and interquartile range. the CFU‐E growth was found inhibited in B and D groups (A: 100; B: 74/54‐83; C: 86/54‐98; D: 46/39‐53 %). the haematocrit values were significantly diminished in rats with renal insufficiency when compared to controls (A: 42/40‐43; B: 45/42‐46; C: 37/32‐40 and D: 37/24‐39 %). Serum Al accumulation was observed in B and D groups receiving Al (A: 8/5‐12; B: 36/36‐44; C: 5/5‐6; D: 45/26‐132 μg Al/l). No differences among groups were found in the liver and kidney Al contents, but uraemic state favoured Al accumulation in brain (A: 6/5.0‐9.0; B: 4/3.8‐4.3; C: 2/1.0‐3.0; D: 15/12.0‐21.0 μg Al/g tissue) and bone (A: 29/27‐31; B: 30/29‐39; C: 42/33‐48; D: 68/56‐79 μg Al/g tissue). We suggest that the heavy accumulation of Al in the bone compartment may result in a protracted endogenous exposure of bone marrow cells, affecting the erythropoiesis in vivo.
Comparison between males and females with lupus nephritis
Authors: KHAJEHDEHI Parviz , RAIS‐JALALI Ghanbarali
Published: April 2007

Summary: In this study 17 male and 100 female cases with lupus nephritis were divided into four groups according to their clinical features at presentation. Each case was compared in order to identify sex‐linked differences in their disease manifestations as well as underlying histopathological features and ultimate prognosis. the World Health Organization (WHO) histologic criteria were used for classification purposes. In all patients, age, chronicity index, duration of clinical activity of the disease before kidney biopsy and follow‐up periods were statistically similar in the two groups of males and females. However, males had a significantly higher activity index in comparison to females at the time of initial kidney biopsy. In addition, diffuse proliferative histopathology was more common in males compared to females (P= 0.002). Moreover, the renal and patient survival was significantly shorter in males as compared to female cases (P= 0.0024, P= 0.0165, respectively). the proportions of males with severe lupus nephritis presenting with hypertension, reduced creatinine clearance, massive proteinuria and reduced levels of complement leading to end‐stage renal disease was significantly higher compared to the females among the four clinical groups of the patients. In conclusion, our data indicates that lupus nephritis in males is a more progressive and severe disease in comparison to female cases. In addition its underlying histopathology is almost always diffuse proliferative lesions, leading to a poorer renal and patient survival in them.
Combination of vasopressin and angiotensin inhibition in experimental focal glomerulosclerosis
Authors: KURIHARA Isao , SAITO Takao , OBARA Katsuya , HIRAI Mariko , SOMA Jun , SATO Hiroshi , ABE Keishi
Published: April 2007

Summary: This study was designed to investigate the role of vasopressin and angiotensin II in the pathogenesis of focal glomerulosclerosis (FGS). A non‐peptide vasopressin VI antagonist (OPC‐21268) and an angiotensin converting enzyme inhibitor (ACE‐I) were administered either alone or in combination for 15 weeks to FGS, spontaneously hypercholesterolaemic rats. Treatment with the V1 antagonist (1% OPC‐21268) suppressed the rise in systolic blood pressure (SBP), serum triglyceride (TG), blood urea nitrogen (BUN) and serum creatinine (S‐Cr) levels, but not the elevations of urinary protein excretion (UPE) or serum total cholesterol (TC) levels. Morphologically, V1 antagonist significantly prevented an increase in the index of glomerular sclerosis (IS) and relative interstitial volume (RIV). In the low dose/high dose of V1 antagonist supplementation, the administration of 0.2% OPC‐21268 failed to suppress any increase in the SBP and TG levels, but significantly preserved renal function and attenuated renal lesions. In the combination study, rats were divided into four groups: (i) V1 antagonist (1% OPC‐21268); (ii) ACEI (imidapril, 5 mg/kg/per day); (iii) both treated groups; and (iv) an untreated control group. Angiotensin‐converting enzyme inhibitor significantly suppressed increases in SBP, UPE, TC, BUN, and S‐Cr levels compared with V1 antagonist. the combination therapy significantly enhanced these effects. Both agents significantly reduced IS and RIV, and combination therapy further reduced these levels. the results indicated that vasopressin, as well as angiotensin II, via the V1 receptor cause hypertension and renal injury in FGS rats. Vi antagonist and ACE‐I have antihypertensive and renoprotective effects in this FGS model, and enhanced their beneficial effects when used as combination therapy.
Intracellular localization of 73 kDa heat‐shock protein in rat kidneys with acute gentamicin nephropathy: an electron microscopic immunohistochemical study
Authors: KOMATSUDA Atsushi , WAKUI Hideki , OHTANI Hiroshi , MIURA Aiura B , ITOH Hideaki , TASHIMA Yohtalou
Published: April 2007

Summary: Recent in vitro studies have suggested a chaperone function of 73 kDa heat‐shock protein (HSP73) in targeting denatured proteins to lysosomes for degradation. We previously reported the induction of HSP73 in rat kidneys with gentamicin‐induced acute tubular injury, and suggested that HSP73 might accumulate in injured lysosomes by observations at light microscopic level. In this study, we examined serial intracellular localizations of HSP73 in this animal model at electron microscopic level. Sprague‐Dawley rats received gentamicin (80 mg/kg per day) for 14 days, and developed acute proximal tubular injury. After the gentamicin exposure, HSP73 moved from the nucleus to the cytoplasm, and was expressed within enlarged lysosomes in the injured proximal tubular epithelial cells. These accumulations started to appear from 36 h after the first gentamicin exposure, enlarged in size until day 12, and gradually diminished after day 18. At day 27, the HSP73 localization pattern returned to that of the normal kidney. We next observed serial intracellular localizations of a renal isoform of argininosuccinate synthetase (ASS), which is not a chaperone protein. Argininosuccinate synthetase was mainly expressed in the cytoplasm of normal proximal tubular epithelial cells. After the gentamicin exposure, ASS also accumulated within the lysosomes, but the magnitude of this lysosomal accumulation was less than that of HSP73. These findings in vivo support the suggested function of HSP73 in lysosomal protein degradation pathways. HSP73 may have a role in the disposition of damaged proteins for the repair of target cells from gentamicin nephrotoxicity.
Intrarenal synthesis of IL‐6 in IgA nephropathy
Authors: MIYAZAKI Masanobu , SUZUKI Daisuke , KOJI Takehiko , YANO Nohiro , YAGAME Mitsunori , ENDOH Masayuki , NOMOTO Yasuo , NIKOLIC‐PATERSON David J , ATKINS Robert C , SAKAI Hideto
Published: April 2007

Summary: Recent in vitro studies have shown the synthesis of interleukin‐6 (IL‐6) in glomerular mesangial and epithelial cells, and suggested the involvement of IL‐6 in mesangial proliferative glomerulonephritis. However, the expression site of IL‐6 mRNA in renal tissue of IgA nephropathy (IgAN), the most common chronic mesangial proliferative glomerulonephritis, remains obscure. to localize IL‐6 mRNA in renal biopsy specimens of IgAN, we used nonradioactive in situ hybridization (ISH) developed in our laboratory, sensitive in detecting individual cells positive for a specific mRNA. In some sections, periodic acid‐Schiff staining was performed after ISH in order to identify the topographical relation between IL‐6 mRNA positive cells and glomerular basement membrane and mesangial area. In situ hybridization for IL‐6 mRNA and immunohistochemistry for CD3 and CD68, markers for lymphocytes and monocytes, respectively, were also performed on serial sections to examine the contribution of infiltrated mononuclear cells to cells positive for IL‐6 mRNA in glomeruli. Glomerular resident cells, including glomerular mesangial and epithelial cells and cells of Bowman's capsule, as well as tubular epithelial cells and infiltrated mononuclear cells expressed IL‐6 mRNA. We also compared the localization of IL‐6 mRNA and protein and showed different distribution between the gene product and protein. the expression of IL‐6 mRNA correlated with the degree of mesangial cell proliferation and tubulointerstitial changes. Our results indicate that IL‐6 is synthesized in renal tissues of IgAN and suggest that the increased IL‐6 expression may be important in the pathogenesis of IgAN.
Molecular analysis of human glomerulonephritis
Authors: NIKOLIC‐PATERSON David J , MAIN Ian W , LAN Hui Y , FOTI Rita , ATKINS Robert C
Published: April 2007

Summary: Understanding the complex mechanisms involved in the induction and progression of glomerulonephritis requires a detailed analysis of the disease at the molecular level. This has become possible with the advent of antibody‐based, and in particular, DNA‐based techologies. This paper provides an overview of the methods of molecular analysis currently in use in the study of human glomerulonephritis. Although largely restricted to the research laboratories at present, these techniques of molecular analysis are now entering the mainstream of clinical diagnostic testing.
The mucosal immune system in IgA nephropathy
Authors: VAN ES LA , DE FIJTER JW , DAHA MR
Published: April 2007

Summary: IgA nephropathy is a clinically and histologically defined syndrome of unknown aetiology, which may have various causes in different parts of the world. Immunologically it is characterized by deposition of IgA1, probably polymeric IgA, in the mesangium and is frequently associated with IgG, C3 and components of the alternative pathway of the complement cascade. the disease can go into complete remission in children, but in adults it usually has a progressive course, characterized by the appearance of proteinuria and hypertension and loss of glomerular filtration rate (GFR). Histologically the development of glomerulosclerosis and tubulo‐interstitial changes correlate with a clinical progressive course. the mucosal immune system is characterized by high plasma IgAl antibody responses after parenteral immunization with viral or bacterial vaccines. However, following nasal challenge with a bacterial neoantigen, IgA nephropathy patients appear to have a defective mucosal immune response in their nasal washes, in their bone marrow and in their plasma IgA1 antibody levels.
Treatment of childhood IgA nephropathy
Authors: YOSHIKAWA Norishige , ITO Hiroshi
Published: April 2007

Summary: Knowledge concerning childhood IgA nephropathy has expanded greatly in the last 10 years, and its importance as the major form of glomerulonephritis and major contributor to the end‐stage renal disease is becoming apparent in children. IgA nephropathy is a slow progressive glomerular disease. Once renal function impairment develops, eventual progression to uraemia is inevitable, therefore a prophylactic approach to the progression of IgA nephropathy, based on an arbitrary period of therapy early in the course of disease in children with IgA nephropathy, warrants serious consideration and investigation. Our recent controlled trial in children with severe glomerular lesions based on renal biopsy demonstrates that 2 year prednisolone therapy combined with azathioprine, dipyridamole and heparin‐warfarin benefits those with clinical evidence of disease of relatively short duration. the development of successful therapy during childhood will offer the potential to reduce the high morbidity and mortality associated with this disease in adults.
CREEP‐FATIGUE BEHAVIOUR OF FOUR CASTS OF TYPE 316 STAINLESS STEEL
Authors: WAREING J.
Published: April 2007

Abstract—

Low‐cycle fatigue tests including hold periods up to 24 h at maximum tensile strain have been conducted on four casts of Type 316 stainless steel in the temperature range 570 to 625°C. These resulted in failure times up to 4000 h. In general, fatigue life is reduced as the hold period increases, but the extent of life reduction varies from material to material and with test temperature. For two casts material this initial life reduction is followed by an increase in life as hold periods are extended. The results are rationalised in terms of prevailing fracture processes, and the implication for the extrapolation of short‐term data is discussed.
A METHOD FOR PREDICTING THE LIFETIME OF GAS TURBINE BLADES
Authors: POLICELLA HUMBERT , CULIÉ JEAN‐PIERRE
Published: April 2007

Abstract—

–The article describes a method developed at ONERA for predicting the lifetime of gas turbine blades. This method makes use of non‐linear viscoplastic constitutive laws, the problem being solved from a plane cross section assumption and through a time‐step linearization. The initiation of the first macroscopic crack is calculated from a stabilized cycle condition. A blade test rig has been developed for checking the method under load and temperature conditions that are as close as possible to operational ones. The results of two series of tests on convection cooled IN100 blades prove the method to be acceptable to design engineers.
THE ENGINEERING FATIGUE PROPERTIES OF WROUGHT COPPER*†
Authors: MURPHY M. C.
Published: April 2007

Abstract—

The paper presents a comprehensive review, supplemented by original data, of the engineering fatigue behaviour of copper. Variations in manufacturing route and softening treatments are shown to have little effect on the fatigue of annealed copper but the high cycle fatigue strength is increased by cold work. The high strain fatigue behaviour is defined in terms of the plastic strain range and the cyclic stress‐strain characteristics are documented. Fatigue behaviour in bending and torsion is defined by data and related to that in tension by simple design rules.

Notches are found to reduce the laboratory measured fatigue strength of copper by ∼ 30% and the effect of surface finish, surface distortion and surface residual stress is defined in the literature. Fatigue crack growth is defined in terms of stress intensity factor range ΔKby an upperbound law and, together with the conditions for non‐growth (ΔK0), shown to relate to the equivalent conditions for steels via the ratio of the respective elastic moduli.

The effect of environment on the fatigue of copper has received scant attention in the literature, such results as exist suggesting little if any reduction in strength to be brought about by gaseous or aqueous environments. The most dramatic change is the improvement of about an order of magnitude which results when tests in vacuum are compared with equivalent tests in air. Results of fatigue tests on copper in ammoniacal environments are conspicuously absent from the literature.

As the test temperature is reduced below room temperature there is a predictable increase in high cycle fatigue strength, a reduction in fatigue strength occurring above room temperature. High strain fatigue test results presented in terms of plastic strain range appear insensitive to temperature although at very low strain rates and high temperatures a reduction in fatigue strength occurs. A linear life fraction cumulative damage creep‐fatigue law appears sometimes to be non‐conservative but much more testing is needed to evaluate fatigue damage summation laws generally for copper.

Numerical data are given in support of all the aspects of the engineering fatigue behaviour reviewed in the paper.
THE APPLICABILITY OF STRAIN‐RANGE PARTITIONING TO HIGH TEMPERATURE LOW CYCLE FATIGUE LIFE PREDICTION OF “IN 738” ALLOY
Authors: NAZMY M. Y.
Published: April 2007

Abstract—

The results of high temperature low cycle fatigue (HTLCF) on IN 738, obtained from two different sources, were used to study the applicability of strain‐range partitioning (SRP) to this alloy. In spite of the difficulty in separating the plastic‐plastic strain component from the different strain‐life relations, an attempt was made to determine the coefficients and exponents for each of these relations from both sets of data. The observation that compressive creep, balanced by tensile plastic deformation, was more damaging than the reverse, could be related to the behaviour of the material. The evidence of the effect of temperature on the plastic‐plastic strain‐life relation, reported by some researches, was shown to be not decisive in the reported temperature range. The reasonable agreement and the similarity in the material's behaviour, obtained from the analysis of the high temperature low cycle fatigue of the two sets of data, substantiates the applicability of the strain‐range partitioning method to IN 738 alloy.
DAMAGE ACCUMULATION DURING INITIATION AND SHORT CRACK GROWTH REGIMES
Authors: MILLER K. J. , IBRAHIM M. F. E.
Published: April 2007

Abstract—

The birth and growth of short cracks is analysed from an elastic‐plastic fracture mechanics viewpoint. Low to high cumulative damage tests from the low stress to high strain regime indicate that there is no crack initiation period in the metallurgical sense and that cracks grow from the first cycle, but at a slow rate. The initiation phase terminates when one crack starts to dominate and accelerates to failure, its initial size being given by
image
for the medium carbon steel tested here, of grain size 56 μm.
THE IMPACT FATIGUE PROPERTIES OF PEARLITIC PLAIN CARBON STEELS
Authors: JOHNSON ALAN A. , KELLER DAVID J.
Published: April 2007

Abstract—

A literature search has revealed that the most extensive study of impact fatigue reported is still that of Stanton and Bairstow (1908) who were the first to work on this topic. Their results, which were on pearlitic plain carbon steels, have been reanalyzed in an attempt to deduce from them the effects of chemical composition on impact fatigue in this class of materials.

The results show that when the number of impacts to failure, Nf, is greater than about 103, Nf and the energy absorbed per impact, Ei, are related by the equation: Ei, =Eo+EkNf−p, where Eo appears to be the impact endurance limit. It is suggested that Ek and p be named respectively the “impact fatigue parameter” and “impact fatigue exponent”. Ek is independent of composition except that it is lower by a factor of about four for two materials which probably failed by an intercrystalline rather than transcrystalline fracture; p has a value of 0.6; and Eo increases monotonically with silicon content but does not vary systematically with the carbon, manganese, sulphur or phorphorus contents. The significance of these results is discussed.
CRYSTALLOGRAPHIC FATIGUE CRACK GROWTH IN NIMONIC AP1
Authors: KING J. E.
Published: April 2007

Recently a controversy has developed over whether crystallographic crack growth near threshold in Ni‐base superalloys occurs along {111} slip planes or {100} planes at room temperature. In this work on Nimonic API crack propagation is shown to occur on both {100} and {111} planes. The most common facet plane is {111} and this is the only orientation observed at the lowest stress intensities, but at higher stress intensities occasional {100} facets are also produced. This behaviour is compared with similar results in aluminium alloys.
FATIGUE LIFE BEHAVIOR OF COPPER SINGLE CRYSTALS. PART I: OBSERVATIONS OF CRACK NUCLEATION
Authors: CHENG ALEX S. , LAIRD CAMPBELL
Published: April 2007

In low strain fatigue, cracks often form in persistent slip bands (PSB) in a wide variety of materials. Observations of crack nucleation involving PSB have been made in copper single crystals by careful interferometric studies. The width, length, step height and thus strain localization in the PSBs remain very stable during saturation, even up to three‐quarters of the life. For a given applied strain amplitude, the specimen will form PSBs having a certain distribution of slip offsets. The fatal crack is found to nucleate in the group of micro‐PSBs having the largest offsets, and the largest strain localization. The PSB volume fraction for a given strain amplitude depends only very slightly on crystal orientation, and the slip offsets not at all. Thus the kinetics of crack nucleation are not affected by orientation. The mechanism of nucleation is concluded to be one of random walk in the slip offsets of PSBs.
CYCLIC STRAIN HARDENING OF 316 STAINLESS STEEL AT ELEVATED TEMPERATURES
Authors: DE LOS RIOS E. R. , BROWN M. W.
Published: April 2007

The cyclic strain hardening occurring during fatigue testing at 550°C was studied in terms of the dislocation structures developed. The dislocations are collected in dense tangles which form the boundaries of a cell structure. The stress required to push through, or eject, a dislocation from the cell boundary predicts the flow stress. These values showed good correlation with the cyclic shear stresses obtained by applying the Tresca criterion, which underlies its usefulness in design under cyclic loads. Carbide particles are shown to precipitate on grain and cell boundaries.
AN UNDERSTANDING OF FATIGUE THRESHOLDS THROUGH THE INFLUENCE OF NON‐METALLIC INCLUSIONS IN STEEL
Authors: MAYES I. C. , BAKER T. J.
Published: April 2007

Abstract —In recent years the low fatigue growth rate regime has been the subject of extensive study revealing its complex and often seemingly inconsistent nature. The value of alternating stress intensity at threshold ΔKTh) is sensitive to a range of variables which include mean stress, stress history, monotonie and cyclic yield strength, grain size and environment. A degree of coherency may be achieved by interpreting the data in terms of a crack closure mechanism which is a function of surface roughness. Experiments, in which the surface roughness (φ) has been altered by the introduction of non‐metallic inclusions, give insight into the significance of crack closure in this regime.
FATIGUE CRACK GROWTH IN A SINTERED TUNGSTEN ALLOY
Authors: ROMAN I. , JINCHUK D.
Published: April 2007

Abstract—Room temperature fatigue crack propagation in a sintered tungsten alloy was studied. The fatigue crack growth rates were found to be identical for the material in the sintered and forged and as sintered conditions. The propagation rates are slower when compared with other metals due to the relatively high Young's modulus of tungsten. The value of the exponentmin Paris' power law equation was found to be 12 which is higher than for most metals. This was ascribed to the activity of a cleavage mechanism through some of the tungsten grains along with the ductile decohesion fatigue mechanism.
THE STRESS INTENSITY FACTOR OF SMALL CRACKS AT NOTCHES
Authors: SCHIJVE J.
Published: April 2007

Abstract— It was found in a previous publication that stress fields around notches are quantitatively very similar, if the peak stress at the notch root (σpeak) and the notch root radius (ρ) are the same. As a consequence, small cracks (length l) should have the same stress intensity factor, if σpeak and ρ are similar. This implies that the geometry factor C in

image

should primarily depend on l/ρ only, and not on other dimensions. Available data on calculated K values was analysed, which confirmed the similarity concept. An equation for C as a function of l/ρ was obtained. It was shown that K‐values calculated with this equation are an accurate approximation for the stress intensity factor of small cracks at notches.
ON THE TRANSITION FROM NEAR‐THRESHOLD TO INTERMEDIATE GROWTH RATES IN FATIGUE
Authors: James M. R. , Morris W. L. , Zurek A. K.
Published: April 2007

Abstract—Evidence is presented that the cyclic stress intensity threshold for fatigue crack growth in A1 2219‐T851 is associated with a critical maximum value of stress intensity,Kc. This relationship is discovered by measuring the local value of stress intensity at the crack tip which is less than the applied stress intensity because of fatigue induced compressive residual stresses in the plastic zone. Crack growth rates and values of the crack tip residual stress are measured as functions of load ratio. For local stress intensities greater thanKc, the growth rate follows a power‐law relationship, increasing monotonically with δK. For local stress intensities belowKc, growth rates are also sensitive to the cyclic stress range, δσ. If the stress range is small, a threshold to growth, typical of long cracks, is seen. When the cracks are short and δσ exceeds a critical value, growth rates are a complex function of both δσ and δK. This behavior is attributed to the effect of δσ on the propagation of the crack front past obstacles such as grain boundaries.
ON LIFE TIME PREDICTIONS WITH THE STRAIN RANGE PARTITIONING METHOD
Authors: HOFFELNER W. , MELTON K. N. , WÜTHRICH C.
Published: April 2007

Abstract— Computer optimization techniques were applied to the strain range partitioning method for lifetime prediction under high temperature low cycle fatigue loading. The experimental data were evaluated using a simultaneous parameter fit determination of the baseline coefficients. This approach gave good predictions whereas a more conventional method did not work. The significance of the linear damage rule and the interaction damage rule is discussed on the basis of a generalised rule containing both as special cases. This formalism was applied to a ferritic steel and a cast nickelbase‐super‐alloy. In both cases a very good agreement between calculated and measured lifetimes was found.
IN‐REACTOR LOW‐CYCLE FATIGUE OF TYPE 0Kh16N15M3B STAINLESS STEEL
Authors: Kiselevsky V. N. , Kharitonov D. F.
Published: April 2007

An investigation has been carried out on austenitic stainless steel 0Kh16N15M3B under normal conditions and also to neutron irradiation of 6.8 × 1016nm‐2s‐1 (E > 0.1 MeV) intensity. Thin‐walled torsion cylindrical specimens were tested in strain‐controlled fully reversed loading mode at 923 K. Various ranges of strain, pre‐loading fluences and half‐cycle hold times (1, 5 and 30min) were applied. Neutron irradiation was found to result in hardening of the steel, stimulating cyclic stress relaxation and a reduction in cyclic life. When acting together, neutron irradiation and static loads cause a more significant reduction in the number of cycles to failure than if summed up as independent factors. Application of a kinetic failure criterion based on a damage parameter enables an estimation to be made of the limiting state of the steel under high‐temperature cyclic loading with hold periods.
ON THE IMPACT FATIGUE CRACK GROWTH BEHAVIOUR OF METALLIC MATERIALS
Authors: Tanaka T. , Nakayama H. , Kimura K.
Published: April 2007

The impact fatigue crack growth characteristics of a low carbon steel and an aluminium alloy were studied. An impact fatigue testing machine of the Hopkinson bar type was used in these experiments to conduct a series of crack growth tests under simple impact stresses.

The following characteristics of impact fatigue crack growth behaviour were revealed: (1) crack growth rate is higher in impact fatigue than in non‐impact fatigue; (2) crack opening ratio in impact fatigue takes a higher value than in non‐impact fatigue; (3) crack tip plastic zone size is smaller in impact fatigue than in non‐impact fatigue.
EFFECT OF LASER BEAM RADIATION ON FATIGUE CRACK GROWTH BEHAVIOUR
Authors: Peiyan Huang , Changchun Li , Qiguang Zheng , Guangxia Li , Lee Hao
Published: April 2007

This paper studies the effect of laser beam radiation on the fatigue crack growth threshold and the crack growth rate in 25CrMnSi steel plate. A comparison of radiated and unradiated specimens permits the derivation of an equation for the fatigue crack growth rate. The results show that radiation can enhance the fatigue threshold and retard crack growth rate.
THE LOW CYCLE IMPACT FATIGUE PROPERTIES OF PEARLITIC PLAIN CARBON STEELS
Authors: Johnson David N. , Johnson Alan A.
Published: April 2007

The results of Stan ton and Bairstow (1908) have been reanalyzed to yield information on the composition dependence of the low cycle impact fatigue properties of pearlitic plain carbon steels. It has been found that the energy absorbed per impact, Ei, and the number of impacts are failure, Nf, are related by the equation:

In this equation q is determined by the carbon, manganese and silicon contents of the steel; Eo is the impact endurance limit; and C and D are constants. The curve represented by this equation intersects that representing the Johnson‐Keller high cycle impact fatigue equation at a value of logeNf equal to 1/C. Thus, the transition from low to high cycle impact fatigue occurs at this value of logeNf.
AN EXPERIMENTAL AND STATISTICAL INVESTIGATION OF SURFACE FATIGUE CRACK INITIATION AND GROWTH
Authors: Ochi Y. , Ishii A. , Sasaki S. K.
Published: April 2007

Surface fatigue crack studies were carried out and statistically analysed from rotating bend fatigue tests in the high cycle region for three metals, copper, stainless steel and mild steel with four ferrite grain sizes. Quantitative observations of the initiation and growth behavior, including coalescence of closely spaced cracks, are discussed and a limiting condition for coalescence is proposed. Statistical properties of initiation, propagation and propagation rate of surface cracks are examined and the effect of different metals and grain sizes is discussed.
LOW CYCLE FATIGUE BEHAVIOUR OF ALLOY 800H AT 600°C—EFFECT OF GRAIN SIZE AND γ′ ‐PRECIPITATE DISPERSION
Authors: Nilsson J.‐O. , Thorvaldsson T.
Published: April 2007

High strain fatigue properties of Alloy 800H have been investigated at 600°C in strain control. The behaviour of solution heat treated material was compared with that of material aged at 550 and 600°C. It was found that both aging treatments extended the fatigue life significantly, the longest fatigue life being observed for fine‐grained material aged at 550°C. The results are explicable in terms of partially reversible plastic flow occurring when the γ′ particles are by‐passed by shearing.
FRETTING FATIGUE IN 0.55C SPRING STEEL AND 0.45C CARBON STEEL
Authors: Tanaka K. , Mutoh Y. , Sakoda S. , Leadbeater G.
Published: April 2007

Abstract— Fretting fatigue strengths of high strength spring steel (JIS SUP9) and low strength medium carbon steel (JIS S45C) were examined by clamping the contact pads of the same individual materials. The pad contact pressures were kept constant at 60 MPa for SUP9 steel and at 45 MPa for S45C steel. The fretting reduced the fatigue strengths by a factor of about two in both the steels. Cyclic J‐integral concepts were successfully employed to predict crack propagation lives using measured data on frictional forces between the fretting pads and the specimens.
AN ASSESSMENT OF CRACK CLOSURE AND THE EXTENT OF THE SHORT CRACK REGIME IN Q1N (HY80) STEEL
Authors: James M. N. , Knott J. F.
Published: April 2007

Abstract— The paper addresses some aspects of the differences in fatigue crack growth rate behaviour and threshold values obtained for long through‐cracks, short through‐cracks and surface cracks. Attention is focused on plasticity induced closure in the wake behind the growing crack tip. For long cracks at high Kmax, closure is found to depend in a linear manner on Kmax, i.e. Kop, increases with the size of the monotonic plastic zone. Closure increases at low δK and this is primarily a consequence of the load shedding procedure. If short through‐cracks are prepared by machining specimens containing long cracks, a substantial part of the plastic wake is removed and this can produce marked effects on the closure contribution during subsequent growth. The length of crack “closed” in a long crack threshold test was found to be of the order of 1 mm. Cracks less than this length exhibited “short crack” behaviour: greater than this length, they behaved as “long cracks”, with plastic wake effects apparently fully operative. Small surface cracks exhibit “long crack” behaviour at lengths as short as 0.2 mm and reasons for this are discussed.
CYCLIC CREEP ACCELERATION AND RETARDATION IN Cr‐Mo‐V ROTOR STEEL AT AMBIENT AND ELEVATED TEMPERATURE RESPECTIVELY
Authors: Wang Zhong‐Ghuang , Rahka Klaus , Laird Campbell
Published: April 2007

The cyclic creep properties of Cr‐Mo‐V rotor steel have been explored at room temperature and elevated temperature by multiple‐step tests with increasing maximum stress (R= 0), and with subsequent tests in partial unloading (0 ≤R < 1). Cyclic creep acceleration is observed at room temperature and cyclic creep retardation at elevated temperature. This behavior is explained in terms of cyclic softening at low temperature and by creep‐dominated deformation at high temperature with a ferritic material considered especially prone to retardation because of the high diffusivity of b.c.c. material. Other interesting effects, such as strain burst phenomena and the observation of anomalously high values of the ratio of diametral strain to axial strain, are also reported.
A PROBABILISTIC MODEL FOR LOWER‐SHELF FRACTURE TOUGHNESS—THEORY AND APPLICATION
Authors: Slatcher Stephen
Published: April 2007

When fitting parametric distributions to fracture toughness data, one will often encounter the situation where there are few data available. In such a situation, additional information obtained from a theoretical model can prove to be of value. A theoretical model is described here, which predicts that lower‐shelf fracture toughness follows a 2‐parameter Weibull distribution with a shape parameter equal to 2 or 4 (depending on the units used for fracture toughness), the scale parameter being determined by the crack front length and a material constant. A rule‐of‐thumb is given for determining when it is an advantage to use this theoretical information, and when it is best to fit a parametric distribution on the basis of the available data alone.
NEAR THRESHOLD FATIGUE CRACK PROPAGATION BEHAVIOUR OF A HETEROGENEOUS MICROSTRUCTURE
Authors: Vaidya W. V.
Published: April 2007

The threshold regime of a heterogeneous, pearlitic‐ferritic microstructure was investigated at R= 0.1. Not only did the ΔKth values vary depending on the test procedure in that da/dN vs ΔK curves before and after ΔKth determination were not identical but transition ΔK values also differed. The observations are correlated with inherent micro‐ structural features.
HUMID AIR EFFECTS ON CRACK TIP PLASTIC WORK IN 1008 STEEL
Authors: Gross T. S. , Joseph A. D.
Published: April 2007

The cyclic plastic work of fatigue crack propagation, Qpw, and the effective surface energy, U, were measured for an annealed 1008 steel in humid air and dry nitrogen using calorimetry Qpw was not significantly affected by the humid air environment suggesting that the hydrogen generated by the oxidation of iron at the crack tip does not strongly affect the cyclic properties for this material U was identical and constant for the two environments for crack growth rates greater than ∼ 100 A/cycle. Below da/dN∼ 100 A/cycle U decreased rapidly with decreasing δK in the humid air environment It was concluded from these two observations that the main effect of hydrogen on crack growth in this alloy was to lower the atomic surface energy, γ, thereby lowering the local fracture stress.
THE EFFECT OF RESIDUAL STRESSES INDUCED BY SHOT‐PEENING ON FATIGUE CRACK PROPAGATION IN TWO HIGH STRENGTH ALUMINIUM ALLOYS
Authors: Mutoh Y. , Fair G. H. , Noble B. , Waterhouse R. B.
Published: April 2007

Abstract— The crack initiation lives of peened specimens of aluminium alloys 7010 and 8090 are shorter than those of unpeened specimens. This is caused by the acceleration of crack initiation due to stress concentration in the rough peened surface, especially at fold‐like defects. The crack growth rate in peened specimens is significantly reduced with increasing ΔK, i.e. with increasing crack length. At a crack length of approximately 0.3 mm this trend is reversed and the crack growth rate rapidly increases and attains the same level of crack growth rate as that in unpeened specimens. The point of smallest crack growth rate roughly corresponds to the point of maximum residual stress. The crack growth rate in a peened specimen has been modelled by assuming the effect of residual stress reduces to the equivalent stress ratio. The predicted results agree well with the experimental data.
NEAR‐THRESHOLD FATIGUE CRACK GROWTH AND CRACK CLOSURE IN A NODULAR CAST IRON
Authors: Ogawa Takeshi , Kobayashi Hideo
Published: April 2007

Abstract— Near‐threshold fatigue crack growth and crack closure were investigated in a nodular cast iron. Fracture surface roughness was promoted by spheroidal graphites. The spheroidal graphites are partially crushed to form powder which accumulates within the crack and thus enhance crack closure. The marked influence of stress ratio on near‐threshold crack growth is due to graphite‐induced crack closure. When the contribution of graphite‐induced crack closure is excluded, the crack growth characteristics are insensitive to stress ratio, and the threshold behaviour for crack growth tends to disappear. In this case, Young's modulus becomes a controlling material parameter for the power law relationship between crack growth rate and stress intensity range.
EVALUATION ON LIMITATION OF LINEAR ELASTIC FRACTURE MECHANICS FOR SMALL FATIGUE CRACK GROWTH
Authors: Tokaji Keiro , Ogawa Takeshi , Harada Yukio
Published: April 2007

Abstract— The growth characteristics of small fatigue cracks were investigated under rotary bending in a high tensile strength steel, and the critical crack length above which linear elastic fracture mechanics (LEFM) is applicable was evaluated systematically from the results of the present study and previous studies in which two steels having different microstructures and strengths were used. It is found that the critical crack length extends over two regions each exhibiting different growth mechanisms. These regions of microstructurally small cracks and mechanically small cracks are found to be a unique function of the microstructural unit size and the yield strength of the materials, respectively. Therefore, using these relationships, it is possible to estimate the critical crack length for a given material.