Mixed-mode stress intensity factors for kink cracks with finite kink length loaded in tension and bending: application to dentin and enamel.

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Bechtle, Sabine; Fett, Theo; Rizzi, Gabriele; Habelitz, Stefan; Schneider, Gerold A

2010-05-01

Fracture toughness resistance curves describe a material's resistance against crack propagation. These curves are often used to characterize biomaterials like bone, nacre or dentin as these materials commonly exhibit a pronounced increase in fracture toughness with crack extension due to co-acting mechanisms such as crack bridging, crack deflection and microcracking. The knowledge of appropriate stress intensity factors which depend on the sample and crack geometry is essential for determining these curves. For the dental biomaterials enamel and dentin it was observed that, under bending and tensile loading, crack propagation occurs under certain constant angles to the initial notch direction during testing procedures used for fracture resistance curve determination. For this special crack geometry (a kink crack of finite length in a finite body) appropriate geometric function solutions are missing. Hence, we present in this study new mixed-mode stress intensity factors for kink cracks with finite kink length within samples of finite dimensions for two loading cases (tension and bending) which were derived from a combination of mixed-mode stress intensity factors of kink cracks with infinitely small kinks and of slant cracks. These results were further applied to determine the fracture resistance curves of enamel and dentin by testing single edge notched bending (SENB) specimens. It was found that kink cracks with finite kink length exhibit identical stress fields to slant cracks as soon as the kink length exceeds 0.15 times the initial straight crack or notch length. The use of stress intensity factor solutions for infinitely small kink cracks for the determination of dentin fracture resistance curves (as was done by other researchers) leads to an overestimation of dentin's fracture resistance of up to 30%. Copyright 2010 Elsevier Ltd. All rights reserved.

Neonatal clavicle fracture in cesarean delivery: incidence and risk factors.

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Choi, Hyun Ah; Lee, Yeon Kyung; Ko, Sun Young; Shin, Son Moon

2017-07-01

Neonatal clavicle fracture in cesarean delivery is rare and has not been extensively studied. We performed a retrospective review of cesarean deliveries with neonatal clavicle fracture during a 12-year period. Maternal and neonatal factors as well as surgical factors related to cesarean delivery for the fracture were determined and compared to the control group to analyze their significance. Among a total 89 367 deliveries during the study period, 36 286 babies were born via cesarean section. Nineteen cases of clavicle fractures in cesarean section were identified (0.05% of total live births via cesarean section). In the analysis of maternal and neonatal risk factors, birthweight, birthweight ≥ 4000  g and maternal age were significantly associated with clavicle fracture in cesarean section. However, clavicle fractures were not correlated with the selected surgical factors such as indication for cesarean section, skin incision to delivery time and incision type of skin and uterus. Logistic regression analysis showed that birthweight was the major risk factor for clavicle fracture. Clavicle fractures complicated 0.05% of cesarean deliveries. The main risk factor related to a clavicle fracture in cesarean section was the birthweight of an infant. As reported in previous studies associated with vaginal delivery, clavicle fracture is considered to be an unavoidable event and may not be eliminated, even in cesarean delivery.

The treatment of residual stress in fracture assessment of pressure vessels

International Nuclear Information System (INIS)

Green, D.; Knowles, J.

1992-01-01

The treatment of weld residual stress in the fracture assessment of cylindrical pressure vessels is considered through partitioning the stress into membrane, bending and self-balancing through wall components. The influence of each on fracture behavior is discussed. Stress intensity factor solutions appropriate to each type of stress are presented. Short range, medium range and long range stress categories are identified according to simple rules relating the effect of increasing crack length to stress intensity factor and ligament net stress. Proposals are made on how the stress intensity factor from these stress types may be incorporated into a Kr, Lr based fracture assessment

Factors affecting functional prognosis of patients with hip fracture

DEFF Research Database (Denmark)

Kristensen, M T

2011-01-01

to just one or two single factors. The current article reviews important factors affecting the functional prognosis, and clinicians are encouraged to include all factors potentially influencing the outcome of patients with hip fracture in their individualised treatment and rehabilitation plan. Especially......Having a hip fracture is considered one of the most fatal fractures for elderly people, resulting in impaired function, and increased morbidity and mortality. This challenges clinicians in identifying patients at risk of worse outcome, in order to optimise and intensify treatment in these patients....... A variety of factors such as age, prefracture function and health status, fracture type, pain, anaemia, muscle strength, and the early mobility level have been shown to influence patient outcome. Thus, the outcome of patients with hip fracture is considered multi-factorial, and can therefore not be related...

X-ray fractography on fatigue fracture surface of high manganese austenitic steel

International Nuclear Information System (INIS)

Akita, Koichi; Misawa, Hiroshi; Kodama, Shotaro; Saito, Tetsuro.

1997-01-01

Fatigue tests were carried out under constant stress amplitude, using a non-magnetic high manganese Mn-Cr steel. X-ray fractography was applied on the fatigue fractured surface to investigate the relationship between stress intensity factor and residual stress or half-value breadth of the X-ray diffraction profile. The fatigue crack propagation rate of this non-magnetic Mn-Cr steel had the same tendency as in the ordinary structural ferritic steels. The relationship between stress intensity factor and the residual stress or half-value breadth of the steel was almost the same as that of the ferritic cyclic work hardening steels. No stress induced transformation was observed on the fracture surface, but the residual stress on the fractured surface was compressive in the high stress intensity factors range, which is typical in the cyclic work hardening steels. The half-value breadth on the fractured surface increased with increasing effective stress intensity factor range. The relationship between the half-value breadth and stress intensity factor range was represented by a linear line regardless of the stress ratio. Therefore, the acting stress intensity factor range at the time of fracture can be estimated from the half-value breadth. The depth of monotonic plastic zone was estimated from the distribution of half-value breadth beneath the fractured surface. The relationship between the maximum stress intensity factor and half-value breadth was expressed by the equation ω m α(K max /σ y ) 2 , where the value of α was 0.025. This is about one sixth of the value for ferritic steels, and the fact shows the severe work hardening occuring in the plastic zone in this manganese steel. (author)

Modified stress intensity factor as a crack growth parameter applicable under large scale yielding conditions

International Nuclear Information System (INIS)

Yasuoka, Tetsuo; Mizutani, Yoshihiro; Todoroki, Akira

2014-01-01

High-temperature water stress corrosion cracking has high tensile stress sensitivity, and its growth rate has been evaluated using the stress intensity factor, which is a linear fracture mechanics parameter. Stress corrosion cracking mainly occurs and propagates around welded metals or heat-affected zones. These regions have complex residual stress distributions and yield strength distributions because of input heat effects. The authors previously reported that the stress intensity factor becomes inapplicable when steep residual stress distributions or yield strength distributions occur along the crack propagation path, because small-scale yielding conditions deviate around those distributions. Here, when the stress intensity factor is modified by considering these distributions, the modified stress intensity factor may be used for crack growth evaluation for large-scale yielding. The authors previously proposed a modified stress intensity factor incorporating the stress distribution or yield strength distribution in front of the crack using the rate of change of stress intensity factor and yield strength. However, the applicable range of modified stress intensity factor for large-scale yielding was not clarified. In this study, the range was analytically investigated by comparison with the J-integral solution. A three-point bending specimen with parallel surface crack was adopted as the analytical model and the stress intensity factor, modified stress intensity factor and equivalent stress intensity factor derived from the J-integral were calculated and compared under large-scale yielding conditions. The modified stress intensity was closer to the equivalent stress intensity factor when compared with the stress intensity factor. If deviation from the J-integral solution is acceptable up to 2%, the modified stress intensity factor is applicable up to 30% of the J-integral limit, while the stress intensity factor is applicable up to 10%. These results showed that

Fracture Risk and Risk Factors for Osteoporosis.

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Schürer, Christian; Wallaschofski, Henri; Nauck, Matthias; Völzke, Henry; Schober, Hans-Christof; Hannemann, Anke

2015-05-25

As the population ages, diseases of the elderly are becoming more common, including osteoporosis. Ways to assess the risk of fracture and the distribution and effects of known risk factors for osteoporosis will be important in planning for future healthcare needs, as well as in the development of preventive strategies. The study population included 6029 men and women aged 20-90 who underwent examination in the second follow-up wave of the Study of Health in Pomerania (SHIP-2) or in the basal SHIP-Trend Study. The risk of fracture was estimated on the basis of quantitative ultrasonography of the calcaneus. Prior fractures and risk factors for osteoporosis were ascertained in standardized interviews. 4.6% of the male subjects and 10.6% of the female subjects were judged to have an elevated risk of fracture. The corresponding percentages among subjects over age 65 were 8.8% for men and 28.2% for women. Even among subjects under age 55, risk factors for osteoporosis were associated with lower bone stiffness: the mean stiffness index was 103/98 (men/women) without risk factors, 99/96 with one risk factor, and 93/95 with more than one risk factor. Logistic regression analysis yielded an odds ratio of 1.89 (95% confidence interval: 1.44-2.50; p<0.01) for prevalent fractures among subjects aged 75 and older compared to subjects under age 55. The data indicate a high prevalence of osteoporosis from age 65 onward. These findings are consistent with those of other studies from Germany and across Europe. Younger men and women should already begin taking steps to counteract modifiable risk factors.

Experimental and numerical determination of critical stress intensity factor of aluminum curved thin sheets under tensile stress

Energy Technology Data Exchange (ETDEWEB)

Heidarvand, Majid; Soltani, Naser; Hajializadeh, Farshid [University of Tehran, Tehran (Iran, Islamic Republic of)

2017-05-15

We determined the fracture toughness of aluminum curved thin sheets using tensile stress tests and finite element method. We applied Linear elastic fracture mechanics (LEFM) and Feddersen procedure to evaluate stress intensity factor of the samples with central wire-cut cracks and fatigue cracks with different lengths to investigate the notch radius effect. Special fixture design was utilized to establish uniform stress distribution at the crack zone. Less than 9 % difference was found between the wire-cut and the fatigue cracked samples. Since generating central fatigue crack with different lengths required so much effort, wire-cut cracked samples were used to determine critical stress intensity factor. Finite element analysis was also performed on one-quarter of the specimen using both the singular Borsum elements and the regular isoparametric elements to further investigate fracture toughness of the samples. It was observed that the singular elements presented better results than the isoparametric ones. A slight difference was also found between the results obtained from finite element method using singular elements and the experimental results.

Threshold intensity factors as lower boundaries for crack propagation in ceramics

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Walter Per-Ole

2004-11-01

Full Text Available Abstract Background Slow crack growth can be described in a v (crack velocity versus KI (stress intensity factor diagram. Slow crack growth in ceramics is attributed to corrosion assisted stress at the crack tip or at any pre-existing defect in the ceramic. The combined effect of high stresses at the crack tip and the presence of water or body fluid molecules (reducing surface energy at the crack tip induces crack propagation, which eventually may result in fatigue. The presence of a threshold in the stress intensity factor, below which no crack propagation occurs, has been the subject of important research in the last years. The higher this threshold, the higher the reliability of the ceramic, and consequently the longer its lifetime. Methods We utilize the Irwin K-field displacement relation to deduce crack tip stress intensity factors from the near crack tip profile. Cracks are initiated by indentation impressions. The threshold stress intensity factor is determined as the time limit of the tip stress intensity when the residual stresses have (nearly disappeared. Results We determined the threshold stress intensity factors for most of the all ceramic materials presently important for dental restorations in Europe. Of special significance is the finding that alumina ceramic has a threshold limit nearly identical with that of zirconia. Conclusion The intention of the present paper is to stress the point that the threshold stress intensity factor represents a more intrinsic property for a given ceramic material than the widely used toughness (bend strength or fracture toughness, which refers only to fast crack growth. Considering two ceramics with identical threshold limits, although with different critical stress intensity limits, means that both ceramics have identical starting points for slow crack growth. Fast catastrophic crack growth leading to spontaneous fatigue, however, is different. This growth starts later in those ceramic materials

Elastic fracture in driven media

International Nuclear Information System (INIS)

Lung Chiwei; Wang Shenggang; Long Qiyi

1999-08-01

Fracture as one of the mechanical properties of materials is structurally dependent. Defects, defect assemblies, grain boundaries and sub-boundaries materials, modify the local stress intensity factors intensively. Brittle fracture prefers to confine to the grain boundary where the specific surface energy is lower than that in the grain. Again, transgranular cracking may occur on the crystal cleavage plane or planes where the local toughness is lowered by dislocation interaction and motion. This paper shows the complexity of the fractal dimension or roughness index of fractured surfaces in materials with metallographic structures or in inhomogeneous media. (author)

Risk Factors for Hip Fracture in Japanese Older Adults

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Takashi Yamashita

2012-09-01

Full Text Available Risk factors for hip fracture in Japanese older populations are understudied compared with Western countries arguably due to the relatively lower prevalence rates in Japan. Nationally representative data from the Nihon University Japanese Longitudinal Study of Aging were analyzed using logistic regression to examine possible risk factors of hip fractures, separately for older women (n = 2,859 and older men (n = 2,108. Results showed that older Japanese women with difficulty bending their knees (OR = 1.9, with diabetes (OR = 1.7 times, and/or with more activity of daily living limitations (OR = 1.1 had higher risks of hip fracture. Older Japanese men with difficulty bending their knees (OR = 2.6, who use more external prescription drugs (OR = 1.9, and with cancer (OR = 2.0 times had higher risks of hip fracture. Further considerations of gender- and culture-specific factors along with the identified risk factors may provide insights into future intervention programs for hip fracture in Japanese older populations.

Dislocation-free zone model of fracture comparison with experiments

International Nuclear Information System (INIS)

Ohr, S.M.; Chang, S.

1982-01-01

The dislocation-free zone (DFZ) model of fracture has been extended to study the relationship between the stress intensity factor, extent of plastic deformation, and crack tip geometry of an elastic-plastic crack as a function of applied stress. The results show that the stress intensity factor K decreases from the elastic value at first slowly, then goes rapidly to zero as the number of dislocations in the plastic zone increases. The crack with a zero stress intensity factor has its crack tip stress field completely relaxed by plastic deformation and hence is called a plastic crack. Between the elastic and plastic cracks, a wide range of elastic-plastic cracks having both a stress singularity and a plastic zone are possible. These elastic-plastic cracks with a DFZ are predicted if there is a critical stress intensity factor K/sub g/ required for the generation of dislocations at the crack tip. The expression for K/sub g/ is obtained from the crack tip dislocation nucleation model of Rice and Thomson. In most metals, the magnitude of K/sub g/ is less than the critical stress intensity factor for brittle fracture K/sub c/. The values of K are determined from electron microscope fracture experiments for various metals and they are found to be in good agreement with the K/sub g/ predicted from the model. It is concluded that for most ductile and semibrittle metals, the mechanism of dislocation generation is more important than the fracture surface energy in determining the stress intensity factor at the crack tip

X-ray analysis on the fatigue fracture surface of stainless steels

International Nuclear Information System (INIS)

Yoshioka, Yasuo; Guimard, B.

1986-01-01

Several X-ray diffraction parameters were observed on the fatigue fracture surface and its vicinity of both of SUS420J1 martensitic and SUS304 austenitic stainless steels and we discussed the relation between the stress intensity factor and these parameters. Monotonic plastic zone depth determined by the measurement of residual stress distribution proportionals to the squre of the maximum stress intensity factor as well as the case of ferritic steel. However, it is very difficult to find the relation between the stress intensity factor and residual stress or half value breadth of X-ray diffraction profile in the fracture surface for both materials. On the other hand, the amount of martensite induced by the transformation during fatigue process in SUS304 is related to the maximum stress intensity factor in the fracture surface regardless the stress ratio R. (author)

Stress intensity factors and constant stress terms for interface cracks

International Nuclear Information System (INIS)

Fett, T.; Rizzi, G.

2004-01-01

In bi-material joints cracks can propagate along the interface or kink into one of the two materials. Whereas the energy release rate can be applied for interface cracks in the same way as usual for homogeneous materials, the computation of stresses in the vicinity of the crack tip is significantly more complicated. In order to assess crack kinking, it is necessary to know the mixed-mode stress intensity factor contributions K I and K II as well as the constant stress terms in the two materials. Whereas the stress intensity factors are available for a large number of infinite and semi-infinite bodies, there is experimental interest in practically used test specimens. This especially holds for the constant x-stress terms. Finite element computations are performed for the special case of a disappearing second Dundurs parameter, i.e. β=0. The fracture mechanics parameters K I , K II , σ 0 for the interface crack are reported in the form of diagrams and approximate relations. (orig.)

Risk factors for hip fracture among institutionalised older people.

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Chen, Jian Sheng; Sambrook, Philip N; Simpson, Judy M; Cameron, Ian D; Cumming, Robert G; Seibel, Markus J; Lord, Stephen R; March, Lyn M

2009-07-01

risk factors for hip fracture in community-dwelling individuals have been extensively studied, but there have been fewer studies of institutionalised older people. a total of 1,894 older people (1,433 females, 461 males; mean age 86 years, SD 7.1 years) were recruited from 52 nursing homes and 30 intermediate-care nursing care facilities in Australia during March 1999 and February 2003. We assessed clinical risk factors for hip fracture and skeletal fragility by calcaneus broadband ultrasound attenuation (BUA) at baseline and then followed up for fracture for 4 years. Hip fractures were validated by x-ray reports. Survival analysis with age as a time-dependent covariate was used to analyse the data. during a mean follow-up period of 2.65 years (SD 1.38), 201 hip fractures in 191 residents were recorded, giving an overall hip fracture incidence rate of 4.0% per person year (males 3.6% and females 4.1%). Residents living in intermediate-care hostels had a higher crude hip fracture rate (4.6% vs. 3.0%) than those living in high-care nursing homes. In multivariate analysis, an increased risk of hip fracture was significantly associated with older age, cognitive impairment, a history of fracture since age 50, lower body weight, longer lower leg length and poorer balance in intermediate-care hostel residents, but not with lower BUA. institutionalised older people, who are at a higher risk of hip fracture than community-dwelling individuals, have differences in some risk factors for hip fracture that should be considered in targeting intervention programs.

Risk Factors for Migration, Fracture, and Dislocation of Pancreatic Stents

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Yoshiaki Kawaguchi

2015-01-01

Full Text Available Aim. To analyze the risk factors for pancreatic stent migration, dislocation, and fracture in chronic pancreatitis patients with pancreatic strictures. Materials and Methods. Endoscopic stent placements (total 386 times were performed in 99 chronic pancreatitis patients with pancreatic duct stenosis at our institution between April 2006 and June 2014. We retrospectively examined the frequency of stent migration, dislocation, and fracture and analyzed the patient factors and stent factors. We also investigated the retrieval methods for migrated and fractured stents and their success rates. Results. The frequencies of stent migration, dislocation, and fracture were 1.5% (5/396, 0.8% (3/396, and 1.2% (4/396, respectively. No significant differences in the rates of migration, dislocation, or fracture were noted on the patient factors (etiology, cases undergoing endoscopic pancreatic sphincterotomy, location of pancreatic duct stenosis, existence of pancreatic stone, and approach from the main or minor papilla and stent factors (duration of stent placement, numbers of stent placements, stent shape, diameter, and length. Stent retrieval was successful in all cases of migration. In cases of fractured stents, retrieval was successful in 2 of 4 cases. Conclusion. Stent migration, fracture, and dislocation are relatively rare, but possible complications. A good understanding of retrieval techniques is necessary.

Risk Factors for Pelvic Insufficiency Fractures in Locally Advanced Cervical Cancer Following Intensity Modulated Radiation Therapy

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Ramlov, Anne, E-mail: anraml@rm.dk [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Pedersen, Erik Morre; Røhl, Lisbeth [Department of Radiotherapy, Aarhus University Hospital, Aarhus (Denmark); Worm, Esben [Department of Medical Physics, Aarhus University Hospital, Aarhus (Denmark); Fokdal, Lars; Lindegaard, Jacob Chr. [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Tanderup, Kari [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Department of Medical Physics, Aarhus University Hospital, Aarhus (Denmark)

2017-04-01

Purpose: To investigate the incidence of and risk factors for pelvic insufficiency fracture (PIF) after definitive chemoradiation therapy for locally advanced cervical cancer (LACC). Methods and Materials: We analyzed 101 patients with LACC treated from 2008-2014. Patients received weekly cisplatin and underwent external beam radiation therapy with 45 Gy in 25 fractions (node-negative patients) or 50 Gy in 25 fractions with a simultaneous integrated boost of 60 Gy in 30 fractions (node-positive patients). Pulsed dose rate magnetic resonance imaging guided adaptive brachytherapy was given in addition. Follow-up magnetic resonance imaging was performed routinely at 3 and 12 months after the end of treatment or based on clinical indication. PIF was defined as a fracture line with or without sclerotic changes in the pelvic bones. D{sub 50%} and V{sub 55Gy} were calculated for the os sacrum and jointly for the os ileum and pubis. Patient- and treatment-related factors including dose were analyzed for correlation with PIF. Results: The median follow-up period was 25 months. The median age was 50 years. In 20 patients (20%), a median of 2 PIFs (range, 1-3 PIFs) were diagnosed; half were asymptomatic. The majority of the fractures were located in the sacrum (77%). Age was a significant risk factor (P<.001), and the incidence of PIF was 4% and 37% in patients aged ≤50 years and patients aged >50 years, respectively. Sacrum D{sub 50%} was a significant risk factor in patients aged >50 years (P=.04), whereas V{sub 55Gy} of the sacrum and V{sub 55Gy} of the pelvic bones were insignificant (P=.33 and P=.18, respectively). A dose-effect curve for sacrum D{sub 50%} in patients aged >50 years showed that reduction of sacrum D{sub 50%} from 40 Gy{sub EQD2} to 35 Gy{sub EQD2} reduces PIF risk from 45% to 22%. Conclusions: PIF is common after treatment of LACC and is mainly seen in patients aged >50 years. Our data indicate that PIFs are not related to lymph node

Spalling fracture of metals and alloys under intense x-radiation

International Nuclear Information System (INIS)

Molitvin, A.M.

2001-01-01

Creation of different power and irradiating installations assisted in studying mechanical properties of structural materials under the effect of high-power radiation fluxes: laser, electron, X-ray, ion beam etc. There are being widely investigated such phenomena as surface and deep hardening of metals and alloys under irradiation, generation of elastic and shock waves, materials failure under thermal shock etc.In the paper there are discussed the results of long researches of spalling fracture of materials and alloys under intense X-radiation. Model assemblies with consequently arranged samples (foils) of metals and alloys under investigation underwent pulse X-radiation. The energy flux of X-radiation was weakened to the needed value by dose filters intensively absorbing soft spectrum of X-radiation. At carrying out the researches the foils of copper, nickel, titanium, brass, bronze, molybdenum, tungsten, tantalum, cadmium, lead, zinc, silver and steels 0.005-1 mm thick were used as objects under investigation. The samples diameter (10-16 mm) was chosen to be quite large as compared to their thickness so that the side load does not affect the central part of the samples and the front (looking the source of X-radiation) and back (shadow) surfaces of the samples are free what makes it possible to consider the processes of spalling fracture in one-dimensional approximation. Within the frames of kinetic approach to the problem of solid states spalling fracture under pulse loading that considers fracture as progressing in time process there were found spalling fracture time dependencies of lead, cadmium, zinc, silver, copper, brass, bronze, nickel, titanium, molybdenum, tungsten, tantalum and steels under thermal shock initiated by X-radiation. It was demonstrated that longevity of metals and alloys under thermal shock exponentially decreases with the growth of rupture stresses amplitude and can be described in terms of kinetic concept of strength.Within the frames of

Analysis on the risk factors of second fracture in osteoporosis-

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RUAN Wen-dong

2011-04-01

Full Text Available 【Abstract】 Objective: To explore the clinical characteristics and risk factors of refracture in patients suffering from osteoporosis-related fractures as well as effective interventions. Methods: From January 2006 to January 2008, both out-patients and in-patients in our hospital who were over 50 years old and suffered from osteoporosis-related fractures were selected for this research. They were divided into fracture group and refracture group. The refracture rate was followed up for 2 years, during which 11 patients developed refracture, thus were included in the refracture group. Therefore, 273 patients, 225 first-fracture cases, aged (67.7± 8.5 years, and 48 refracture cases, aged (72.7±9.5 years, were included in this study. General data including age and sex, fracture types, femoral neck bone mineral density (BMD T-scores tested by dual-energy X-rays absorptiometry (DEXA, Charlson index, time-frame between two fractures as well as mobility skill assessment were collected and analyzed by single-factor and multivariate statistical methods. Results: Females accounted for 70.2% of the fracture group and 77.1% of the refracture group. The most common refracture type was vertebral fracture for the first time and femoral neck fracture for the second time during the followup. The second fracture happened 3.7 years after the first one on average. The refracture rate was 2.12% within one year, and 4.66% within two years. Risk factors for a second fracture in osteoporotic fracture patients included age (>75 years, HR=1.23, 95%CI 1.18-1.29; >85 years, HR=1.68, 95% CI 1.60-1.76, female sex (HR=1.36, 95%CI 1.32-1.40, prior vertebral fractures (HR=1.62, 95%CI 1.01-2.07, prior hip fractures (HR=1.27, 95%CI 0.89-2.42, BMD T-score<-3.5 (HR=1.38, 95%CI 1.17-1.72 and weakened motor skills (HR=1.27, 95%CI 1.09-1.40. Conclusions: The risks of second fracture among patients with initial brittle fracture are substantial. There is adequate time between the

Factors affecting visualization of posterior rib fractures in abused infants

International Nuclear Information System (INIS)

Kleinman, P.K.; Adams, V.I.; Blackbourne, B.D.; Marks, S.C.

1987-01-01

Rib fractures in abused infants commonly occur in the posterior rib arcs. Fractures occurring near the costovertebral articulations are usually identified radiographically only once callus has formed. To assess the factors influencing the visibility of fractures near the costovertical articulations, the authors studied 103 posterior rib fractures occurring in 16 abused infants. Radiologic findings were correlated with CT findings and pathologic material from nine ribs in four patients. The limited visibility of fractures relates to (1) the frequent superimposition of the transverse process over the rib fracture site, (2) a fracture line that crosses at an obliquity to the x-ray beam, and (3) nondisplacement of rib fragments due to preservation of the posterior periosteum. Fresh rib fractures invisible on a frontal projection may be clearly defined on axial CT scans, or on postmortem radiographs. A knowledge of the factors influencing the visibility of these important injuries is useful in planning an appropriate diagnostic evaluation of suspected infant abuse

Epidemiology and risk factors of humerus fractures among skiers and snowboarders.

Science.gov (United States)

Bissell, Benjamin T; Johnson, Robert J; Shafritz, Adam B; Chase, Derek C; Ettlinger, Carl F

2008-10-01

The incidence of humerus fractures while participating in snowboarding and skiing is undefined. Very little is known about the risk factors associated with these fractures. Snowboarders are at increased risk for sustaining humerus fractures when compared with skiers. In addition, the types of fractures, laterality, and risk factors differ between the 2 groups. Case-control study; Level of evidence, 3. At a major ski area clinic, 318 humerus fractures were evaluated over 34 seasons. Radiographs were classified according to the AO and Neer systems. Patient data were analyzed and compared with that of a control population of uninjured skiers and snowboarders to determine incidence and risk factors. The incidence of humerus fractures among snowboarders (0.062 per 1000 snowboarder days) was significantly higher than that of skiers (0.041 per 1000, P Jumping was involved in 28.3% of humerus fractures among snowboarders and in 5.4% among skiers. Skiers with humerus fractures were more skilled, older, and fell less frequently than controls. Snowboarders were less skilled, younger, and fell at a similar rate compared with controls. Snowboarders are at significantly higher risk of sustaining humerus fractures than skiers. In skiers, humerus fractures show no laterality and most often involve the proximal humerus. In contrast, snowboarders more often fracture the left humerus at the diaphysis.

Risk Factors of the Hip Fractures in Elderly Patients

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Ali Reza Nik-Tab'e

2001-12-01

Full Text Available Objective: The hip fractures are the most frequent cause of traumatic death after the age of 75 years, occurring more frequently in women that will make a negative impact of the patient's life style. The purpose of this research was to evaluate the risk factors of the hip fractures in elderly hospitalized in centers of education and treatment of Kerman and Rafsanjan cities in 1998-2000. Methods and Materials & Methods: This study was a descriptive method of sampling during 27 months (from 19 April 1998 to 21 July 2000 in hospitalized patients of orthopedic wards of Ali ebne Abitaleb hospital of Rafsanjan and Shahid bahonar hospital of Kerman. 257 patients who were afflicted with hip fracture were evaluated by a questionnaire with 20 statements (risk factors of hip fractures that was used to recorded information about this study: This risk factors were including age, sex, type of fracture, osteoporosis, milk consumption, muscle atrophy, environmental hazards, body mass index diseases, diabetes, previous fracture, smoking, antidepressant and anti convulsion drugs, heart disease, low mobility and activity perception disorders, age of menopause, impaired visual and nonuse external hip protector (padding. Results: The results of this study showed that many of above risk factors were effective (>50% than others. These factors were including environmental hazards (81.7%, muscle atrophy (72.8%, previous fractures (52.1%, low mobility and activity (70.8%, low milk consumption (100%, low BMI (79.8%, osteoporosis (52.1% and nonuse external hip protector (100%. Conclusion: The results of this study recommend that environmental hazards of elderly should be modified (e.g. well lighted, stair case with secure hand rail to prevent from falling Exercise and faradic current prevent muscle atrophy and improve physical fitness, muscle strength, balance and coordination. Treatment of impaired visual is important because risk of falling is decreased. Regular load

Factors contributing to the surgical retreatment of mandibular fractures

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João Gualberto de Cerqueira Luz

2013-06-01

Full Text Available The purpose of this retrospective study was to evaluate contributing factors in patients requiring surgical retreatment of mandibular fractures. Of all the patients with mandibular fractures who were treated using internal fixation at a trauma hospital over a seven-year period, 20 patients (4.7% required a second surgery and thus composed the “reoperated” group. The control group comprised 42 consecutive patients with mandibular fractures who were treated at the same clinic and who healed without complications. Medical charts were reviewed for gender, age, substance abuse history, dental condition, etiology, location of fracture, degree of fragmentation, fracture exposure, teeth in the fracture line, associated facial fractures, polytrauma, time elapsed between trauma and initial treatment, surgical approach and fixation system. Statistical analyses were performed using the Statistical Package for Social Sciences (SPSS version 20.0; descriptive statistics and the chi-squared test were used to determine differences between groups. Significant differences in substance abuse (p = 0.006, dental condition (p < 0.001, location of fracture (p = 0.010, degree of fragmentation (p = 0.003 and fracture exposure (p < 0.001 were found. With regard to age and time elapsed between trauma and initial treatment, older patients (31.4 years, SD = 11.1 and a delay in fracture repair (19.1 days, SD = 18.7 were more likely to be associated with reoperation. It was concluded that substance abuse, age, dental condition, location of fracture, degree of fragmentation, fracture exposure and the time between trauma and initial treatment should be considered contributing factors to the occurrence of complications that require surgical retreatment of mandibular fractures.

Experimental control of calculation model of scale factor during fracture of circular samples with cracks

International Nuclear Information System (INIS)

Gnyp, I.P.; Ganulich, B.K.; Pokhmurskij, V.I.

1982-01-01

Reliable methods of estimation of cracking resistance of low-strength plastic materials using the notched samples acceptable for laboratory tests are analysed. Experimental data on the fracture of round notched samples for a number of steels are given. A perfect comparability of calculational and experimental data confirms the legitimacy of the proposed scheme of estimation of the scale factor effect. The necessity of taking into account the strain hardening coefficient at the choice of a sample size for determining the stress intensity factor is pointed out

Risk factors for falls within the first 3 months after a fracture.

OpenAIRE

GEUSENS, Piet; Helden, SV; Wyers, C; Dagnelie, PC; Pijpers, E; Willems, G; Brink, P; Linden, SV; Nieuwenhuijzen-Kruseman, A

2006-01-01

A history of fracture indicates a risk for future fractures. The absolute risk is highest in the first year after a clinical fracture. We investigated the incidence offalls and fracture and the risk factors for falls within 3 months after a fracture. We included 296 consecutive men and women aged 50 years who presented to the hospital with a clinical fracture. Risk factors for falls were assessed according to the guidelines on fall prevention in the Netherlands. Osteoporosis wa...

Epidemiology and risk factors of lower limb fractures (literature review

Directory of Open Access Journals (Sweden)

N.V. Grygorieva

2017-08-01

Full Text Available The article presents current data about the risk factors of main lower limb fractures (LLFs of different localization (femur, tibia and foot. It has been shown that the most studies examine epidemiology and risk factors for hip fractures, but information about the risk factors for other LLFs is insufficient and controversial. It has been demonstrated that in addition to factors of age and sex, the road traffic accidents, sports, inadequate physical activity, injuries, falls and previous fractures play the important role in the development of LLFs. Also some diseases (systemic osteoporosis, large joints osteoarthritis, rheumatoid arthritis, dementia, epilepsy, alcoholism, parkinsonism, cancer, obesity and cataract can influence the LLFs risk. Administration of some drugs, in particular, hypnotic and sedative, as well as antidepressants, antipsychotic drugs and glucocorticoids, is the additional risk factor for LLFs. Almost all types of fractures in women are associated with low bone mineral density, which is more defined at femoral neck than at spine or peripheral skeleton, but part of fractures associated with osteoporosis is small and ranges from 10 to 44 %. The assessment of risk factors should necessarily be carried out in routine clinical practice in patients with LLFs, since it affects not only their incidence, but also the prognosis of treatment of these patients.

Clinical factors affecting pathological fracture and healing of unicameral bone cysts.

Science.gov (United States)

Urakawa, Hiroshi; Tsukushi, Satoshi; Hosono, Kozo; Sugiura, Hideshi; Yamada, Kenji; Yamada, Yoshihisa; Kozawa, Eiji; Arai, Eisuke; Futamura, Naohisa; Ishiguro, Naoki; Nishida, Yoshihiro

2014-05-17

Unicameral bone cyst (UBC) is the most common benign lytic bone lesion seen in children. The aim of this study is to investigate clinical factors affecting pathological fracture and healing of UBC. We retrospectively reviewed 155 UBC patients who consulted Nagoya musculoskeletal oncology group hospitals in Japan. Sixty of the 155 patients had pathological fracture at presentation. Of 141 patients with follow-up periods exceeding 6 months, 77 were followed conservatively and 64 treated by surgery. The fracture risk was significantly higher in the humerus than other bones. In multivariate analysis, ballooning of bone, cyst in long bone, male sex, thin cortical thickness and multilocular cyst were significant adverse prognostic factors for pathological fractures at presentation. The healing rates were 30% and 83% with observation and surgery, respectively. Multivariate analysis revealed that fracture at presentation and history of biopsy were good prognostic factors for healing of UBC in patients under observation. The present results suggest that mechanical disruption of UBC such as fracture and biopsy promotes healing, and thus watchful waiting is indicated in these patients, whereas patients with poor prognostic factors for fractures should be considered for surgery.

Risk Factors for Pelvic Insufficiency Fractures in Locally Advanced Cervical Cancer Following Intensity Modulated Radiation Therapy

DEFF Research Database (Denmark)

Ramlov, Anne; Pedersen, Erik Morre; Røhl, Lisbeth

2017-01-01

and underwent external beam radiation therapy with 45 Gy in 25 fractions (node-negative patients) or 50 Gy in 25 fractions with a simultaneous integrated boost of 60 Gy in 30 fractions (node-positive patients). Pulsed dose rate magnetic resonance imaging guided adaptive brachytherapy was given in addition......PURPOSE: To investigate the incidence of and risk factors for pelvic insufficiency fracture (PIF) after definitive chemoradiation therapy for locally advanced cervical cancer (LACC). METHODS AND MATERIALS: We analyzed 101 patients with LACC treated from 2008-2014. Patients received weekly cisplatin...

Stress fracture risk factors in female football players and their clinical implications.

Science.gov (United States)

Warden, Stuart J; Creaby, Mark W; Bryant, Adam L; Crossley, Kay M

2007-08-01

A stress fracture represents the inability of the skeleton to withstand repetitive bouts of mechanical loading, which results in structural fatigue, and resultant signs and symptoms of localised pain and tenderness. Reports of stress fractures in female football players are not prevalent; however, they are probably under-reported and their importance lies in the morbidity that they cause in terms of time lost from participation. By considering risk factors for stress fractures in female football players it may be possible to reduce the impact of these troublesome injuries. Risk factors for stress fractures in female football players include intrinsic risk factors such as gender, endocrine, nutritional, physical fitness and neuromusculoskeletal factors, as well as extrinsic risk factors such as training programme, equipment and environmental factors. This paper discusses these risk factors and their implications in terms of developing prevention and management strategies for stress fractures in female football players.

Fracture Mechanics

CERN Document Server

Zehnder, Alan T

2012-01-01

Fracture mechanics is a vast and growing field. This book develops the basic elements needed for both fracture research and engineering practice. The emphasis is on continuum mechanics models for energy flows and crack-tip stress- and deformation fields in elastic and elastic-plastic materials. In addition to a brief discussion of computational fracture methods, the text includes practical sections on fracture criteria, fracture toughness testing, and methods for measuring stress intensity factors and energy release rates. Class-tested at Cornell, this book is designed for students, researchers and practitioners interested in understanding and contributing to a diverse and vital field of knowledge. Alan Zehnder joined the faculty at Cornell University in 1988. Since then he has served in a number of leadership roles including Chair of the Department of Theoretical and Applied Mechanics, and Director of the Sibley School of Mechanical and Aerospace Engineering.  He teaches applied mechanics and his research t...

Study on predicting residual life of elevator links by fracture mechanics approach

Energy Technology Data Exchange (ETDEWEB)

Li Helin; Zhang Yi; Deng Zengjie [China National Petroleum Corp., Xi`an, Shaanxi (China). Tubular Goods Research Center; Jin Dazeng [Xi`an Jiaotong Univ., Xi`an, Shaanxi (China)

1995-12-31

On the basis of investigation, failure and fracture analysis of elevator links, residual life prediction of links using fracture mechanics approach is studied, and mechanical properties, fracture toughness value K{sub IC} and fatigue crack propagation rage da/dN of the steel for elevator links are determined. Using the relation between stress intensity factor K{sub I} and the strain-energy release rate, the two-dimensional conversion thickness finite element method has been used to calculate the stress intensity factors K{sub I} for dangerous sections in the ring part of links. Furthermore, the reliability of calculations of the finite element stress intensity factors K{sub I} for dangerous sections of elevator links and the residual life computation for links are verified by fatigue tests of actual links. Finally, the experimental verification of computed results by 150T link fractured at site indicates that the computed critical crack lengths and residual life tally well with those measured and meet the needs of oil drilling.

Factors Associated with Infection Following Open Distal Radius Fractures

OpenAIRE

Glueck, Dane A.; Charoglu, Constantine P.; Lawton, Jeffrey N.

2009-01-01

Open fractures are often classified according to a system described by Gustilo and Anderson. However, this system was applied to open long bone factures, which may not predict the incidence of infection in open metaphyseal fractures of the upper extremity. Other studies have found that wound contamination and systemic illness were the best predictors of infections in open hand fractures. Our study assessed infection in open distal radius fractures and identifies factors that are associated wi...

Determination of Stress Intensity Factor K1 from Two Fringe Orders by Fringe Multiplication and Sharpening

International Nuclear Information System (INIS)

Chen, Lei; Baek, Tae Hyun

2007-01-01

Stress intensity factor is one of the most important parameters in fracture mechanics. Both the stress field distribution and the crack propagation are closely related to these parameters. Due to the complexity of actual engineering problems, it is difficult to calculate the stress intensity factor by theoretical formulation, so photoelasticity method is a good choice. In this paper, modified two parameter method is employed to calculate stress intensity factor for opening mode by using data from more than one photoelastic fringe loop. For getting accurate experiment results, the initial fringes are doubled and sharpened by digital image programs from the fringe patterns obtained by a CCD camera. Photoelastic results are compared with those obtained by the use of empirical equation and FEM. Good agreement shows that the methods utilized in experiments are considerably reliable. The photoelastic experiment can be used for bench mark in theoretical study and other experiments

Histomorphometrical analysis on the effects of two therapeutic ultrasound intensities on fracture healing in aged rats

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Jeronimo Rafael Skau

Full Text Available Introduction Experimental studies conducted in young animals show that therapeutic ultrasound (TUS has been successfully used to shorten the healing time of bone fractures. However, they were not found in the literature, studies comparing the effect of different intensities of UST in aged animals. Objective To test the efficacy of intensity 1.0 W/cm2 and of 0.5 W/cm2 in the consolidation of experimental fracture of the tibia from aged Wistar rats. Materials and methods Three groups of 15 month old rats were submitted to a midshaft osteotomy of the tibia and then, the hind member was immobilized with a metal splint and plaster of Paris, wrapping the knee and ankle joint. One group (L, received ultrasound at 0.5 W/cm2; the other group (I, were exposed to ultrasound at 1.0 W/cm2. One control group (C, did not receive the ultrasound. Fifteen animals (five from each group were euthanatized at the end of the first week and fifteen (five from each group at the end of the third week. The progress of the fracture healing was performed for each group by morphometric analysis of histological sections of the fracture region. Results and conclusion The results showed that fractures treated with ultrasound at 1.0 W/cm2 healed significantly faster than did the fractures treated with ultrasound at 0.5 W/cm2 and the control.

Hyponatremia, a risk factor for osteoporosis and fractures in women

DEFF Research Database (Denmark)

Holm, J P; Amar, A O S; Hyldstrup, L

2016-01-01

Hyponatremia has been linked to an increased risk of osteoporosis and fractures. We found an increased hazard ratio of major osteoporotic fractures adjusted for potential confounders, including osteoporosis and medication. A reduced BMD was not sufficiently explaining the association. Our data...... indicate that hyponatremia should be considered a risk factor for osteoporosis and fractures. INTRODUCTION: Hyponatremia is the most common electrolyte disorder in clinical practice and could be a risk factor for both osteoporosis and fractures. Mild hyponatremia has traditionally been regarded as a benign...... and asymptomatic condition; however, data from large population and animal studies have led to a reappraisal of this view. The purpose of this study was to evaluate the association of hyponatremia with osteoporosis and major osteoporotic fractures (MOF) in women. METHODS: This is a historical cohort study...

Forefoot Adduction Is a Risk Factor for Jones Fracture.

Science.gov (United States)

Fleischer, Adam E; Stack, Rebecca; Klein, Erin E; Baker, Jeffrey R; Weil, Lowell; Weil, Lowell Scott

Jones fractures are among the most common fractures of the foot; however, much remains unknown about their etiology. The purpose of the present study was to further examine the risk factors of forefoot and hindfoot alignment on Jones fractures using an epidemiologic study design. We used a retrospective, matched, case-control study design. Cases consisted of patients with acute, isolated Jones fractures confirmed on plain film radiographs seen at our institute from January 2009 to December 2013. Patients presenting with pain unrelated to metatarsal fractures served as controls. Controls were matched to cases by age (±2 years), gender, and year of presentation. Weightbearing foot radiographs were assessed for 13 angular relationships by a single rater. Conditional multivariable logistic regression was used to identify important risk factors. Fifty patients with acute Jones fractures and 200 controls were included. The only significant variables in the final multivariable model were the metatarsus adductus angle (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.08 to 1.25) and fourth/fifth intermetatarsal angle (OR 0.69, 95% CI 0.57 to 0.83)-both measures of static forefoot adduction. The presence of metatarsus adductus (defined as >15°) on foot radiographs was associated with a 2.4 times greater risk of a Jones fracture (adjusted OR 2.4, 95% CI 1.2 to 4.8). We have concluded that the risk of Jones fracture increases with an adducted forefoot posture. In our population, which consisted primarily of patients presenting after a fall (10 of 50; 20%) or misstep/inversion injury (19 of 50; 38%), the hindfoot alignment appeared to be a less important factor. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Risk factors for trochanteric and femoral neck fracture.

Science.gov (United States)

Díaz, A R; Navas, P Z

The differences between the two main types of fracture of proximal end of the femur, trochanteric and cervical fractures, are still a subject of study, and could be the key to a better understanding of its pathophysiology and prevention. The aim of this study is to determine whether epidemiological differences in the distribution of risk factors associated with hip fracture exist between these two entities. A descriptive cross-sectional study of 428 patients over the age of 65 admitted for trochanteric or cervical fractures in 2015, in which gender, age, previous diagnosis, external causes associated with fracture and place of the event were recorded. There were 220 patients with a cervical fracture (51.4%) and 208 patients with a trochanteric fracture (48.6%). The average age was higher in the trochanteric fracture, observing a constant increase with age only in women with trochanteric fractures. Cervical fracture showed a significant association with cerebrovascular disease (p=0.039) and trochanteric fracture with accidental falls (p=0.047) and presence of 5-9 previous diseases (p=0.014). A regression analysis maintained this association in the case of a cerebrovascular disease (OR 2.6, 95%CI 1.1-6.4) and the presence of 5-9 diseases (OR 1.5, 95%CI 1.1-2.3). Trochanteric fractures are associated with women patients of more advanced ages, 5-9 previous diseases and accidental falls. Cerebrovascular disease shows a higher prevalence in cervical fractures. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Risk-factors for surgical delay following hip fracture.

Science.gov (United States)

Sanz-Reig, J; Salvador Marín, J; Ferrández Martínez, J; Orozco Beltrán, D; Martínez López, J F

To identify pre-operative risk factors for surgical delay of more than 2 days after admission in patients older than 65 years with a hip fracture. A prospective observational study was conducted on 180 hip fractures in patients older than 65 years of age admitted to our hospital from January 2015 to April 2016. The data recorded included, patient demographics, day of admission, pre-fracture comorbidities, mental state, level of mobility and physical function, type of fracture, antiaggregant and anticoagulant medication, pre-operative haemoglobin value, type of treatment, and surgical delay. The mean age of the patients was 83.7 years. The mean Charlson Index was 2.8. The pre-fracture baseline co-morbidities were equal or greater than 2 in 70% of cases. Mean timing of surgery was 3.1 days. At the time of admission, 122 (67.7%) patients were fit for surgery, of which 80 (44.4%) underwent surgery within 2 days. A Charlson index greater than 2, anticoagulant therapy, and admission on Thursday to Saturday, were independently associated with a surgical delay greater than 2 days. The rate of hip fracture patients undergoing surgery within 2 days is low. Risk factors associated to surgical delay are non-modifiable. However, their knowledge should allow the development of protocols that can reduce surgical delay in this group of patients. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Assessment of a Boat Fractured Steering Wheel

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Vukelic Goran

2016-09-01

Full Text Available During regular use of the steering wheel mounted on a boat, two cracks emanating from a fastener hole were noticed which, consequently, caused final fracture of the wheel. To determine the behavior of a boat steering wheel with cracks present, assessment of a fractured wheel was performed. Torque moments of the fasteners were measured prior to removing the steering wheel from the boat. Visual and dye penetrant inspection followed along with the material detection. Besides using experimental procedures, assessment of the fractured wheel was performed using finite element analysis, i.e. stress intensity factor values were numerically determined. Variation of stress intensity factor with crack length is presented. Possible causes of crack occurrence are given and they include excessive values of fastener torque moments coupled with fretting between fastener and fastener hole that was poorly machined. Results obtained by this assessment can be taken for predicting fracture behavior of a cracked steering wheel and as a reference in the design, mounting and exploitation process of steering wheels improving that way their safety in transportation environment.

Fracture mechanical treatment of bridging stresses in ceramics

International Nuclear Information System (INIS)

Fett, T.; Munz, D.

1993-12-01

Failure of ceramic materials often starts from cracks which can originate at pores, inclusions or can be generated during surface treatment. Fracture occurs when the stress intensity factor of the most serious crack in a component reaches a critical value K lc , the fracture toughness of the material. In case of ideal brittle materials the fracture toughness is independent of the crack extension and, consequently, identical with the stress intensity factor K l0 necessary for the onset of stable crack growth. It is a well-known fact that failure of several ceramics is influenced by an increasing crack-growth resistance curve. Several effects are responsible for this behaviour. Crack-border interactions in the wake of the advancing crack, residual stress fields in the crack region of transformation-toughened ceramics, the generation of a micro-crack zone ahead the crack tip and crack branching. The effect of increasing crack resistance has consequences on many properties of ceramic materials. In this report the authors discuss the some aspects of R-curve behaviour as the representation by stress intensity factors or energies and the influence on the compliance using the bridging stress model. (orig.) [de

[Is Mapuche ethnicity a risk factor for hip fracture in aged?].

Science.gov (United States)

Sapunar, Jorge; Bravo, Paulina; Schneider, Hermann; Jiménez, Marcela

2003-10-01

Ethnic factors are involved in the risk for osteoporosis and hip fracture. To assess the effect of Mapuche ethnicity on the risk of hip fracture. A case control study. Cases were subjects over 55 years of age admitted, during one year, for hip fracture not associated to major trauma or tumors. Controls were randomly chosen from other hospital services and paired for age with cases. The magnitude of the association between ethnicity and hip fracture was expressed as odds ratio in a logistic regression model. In the study period, 156 cases with hip fracture were admitted. The proportion of subjects with Mapuche origin was significantly lower among cases than controls (11.8 and 26.5% respectively, p Mapuche ethnicity was associated with hip fracture with an odds radio of 0.14 (p = 0.03, 95% CI 0.03-0.8). In this sample, Mapuche ethnicity is a protective factor for hip fracture.

Risk factors for fracture in elderly men: a population-based prospective study

DEFF Research Database (Denmark)

Nielsen, Morten Frost; Abrahamsen, Bo; Masud, T

2012-01-01

.30-3.09) and pulmonary illness (1.90; 1.03-3.53) were associated with increased risk of osteoporotic fractures in adjusted models. CONCLUSION: These results underline the importance of assessment of dizziness, falls and those with a family history of hip fracture. Frequent urination and erectile dysfunction were......Risk factors for fractures were assessed in a random sample of 4,696 elderly men followed for 5.4 years. Results highlighted the importance of assessment of falls and dizziness as well as novel risk factors including frequent urination and erectile dysfunction. INTRODUCTION: Knowledge about risk...... in the forearm). Cox proportional hazard regression models were used to evaluate risk factors for any and osteoporotic fractures. The following variables were found to be associated with increased risk of any fracture in adjusted models family history of a hip fracture (HR; 95%CI: 1.56; 1.05-2.33), falls (2...

Factors associated with infection following open distal radius fractures.

Science.gov (United States)

Glueck, Dane A; Charoglu, Constantine P; Lawton, Jeffrey N

2009-09-01

Open fractures are often classified according to a system described by Gustilo and Anderson. However, this system was applied to open long bone fractures, which may not predict the incidence of infection in open metaphyseal fractures of the upper extremity. Other studies have found that wound contamination and systemic illness were the best predictors of infections in open hand fractures. Our study assessed infection in open distal radius fractures and identifies factors that are associated with these infections. We hypothesize that contamination, rather than absolute wound size, is the best predictor of infection associated with open distal radius fractures. A review by CPT code yielded 42 patients with open distal radius fractures between 1997 and 2002 treated at a level one trauma center. Medical records and radiographic follow-up were reviewed to assess the time to irrigation and debridement, the number of debridements in initial treatment period, the method of operative stabilization, the Gustilo and Anderson type of fracture, the Swanson type of fracture, and description of wound contamination. Forty-two patients were followed up for an average of 15 months (range 4 to 68 months). Twenty-four fractures were classified as Gustilo and Anderson type I, ten were type II, and eight were type III, 30 were Swanson type I, and 12 were Swanson type II. Five of the 42 fractures were considered contaminated. Two were exposed to fecal contamination. The others were contaminated with tar, dirt/grass, and gravel, respectively. Three of 42 (7%) fractures developed infections. All three infected cases received a single irrigation and debridement. Two of five contaminated fractures (40%) developed a polymicrobial infection. Both were exposed to fecal contamination and, therefore, considered Swanson type II fractures. They were classified as Gustilo and Anderson type II and IIIB based solely upon the size of the wound. Both required multiple debridements and eventually wrist

The Fracture Toughness of Nuclear Graphites Grades

Energy Technology Data Exchange (ETDEWEB)

Burchell, Timothy D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Erdman, III, Donald L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lowden, Rick R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunter, James A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hannel, Cara C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-04-01

New measurements of graphite mode I critical stress intensity factor, KIc (commonly referred to as the fracture toughness) and the mode II critical shear stress intensity, KIIc, are reported and compared with prior data for KIc and KIIc. The new data are for graphite grades PCEA, IG-110 and 2114. Variations of KIc and acoustic emission (AE) data with graphite texture are reported and discussed. The Codes and Standards applications of fracture toughness, KIc, data are also discussed. A specified minimum value for nuclear graphite KIc is recommended.

Differential impact of some risk factors on trochanteric and cervical hip fractures.

Science.gov (United States)

Tal, Sari; Gurevich, Alexander; Sagiv, Shaul; Guller, Vladimir

2015-04-01

To investigate the potential distinct risk factors associated with trochanteric and cervical hip fractures. Elderly patients aged 65 years and older (n = 1161) were admitted to the orthopedic department with hip fractures during the years 2006-2011. Demographic and clinical data, as well as routine blood tests, were retrieved from the patient electronic medical records. Approximately 58% of patients had trochanteric fractures and 42% had cervical fractures. Women were more likely to have trochanteric fractures than men (P = 0.002). Female sex, frailty, falls, diabetes and subnormal calcium, as well as subnormal hemoglobin levels, were significant risk factors for trochanteric fractures (OR 1.39, P = 0.0202, OR 1.36, P = 0.0166, OR 1.49, P = 0.0015, OR 1.33, P = 0.0343, OR 0.68, P = 0.0054, OR 0.70, P = 0.0036, respectively). Patients with Parkinson's disease were at a lower risk for trochanteric fractures (OR 0.6, P = 0.007). As there are some differences between risk factors for trochanteric and cervical hip fractures, there is a need for further studies in order to understand the etiology of fractures and to be able to carry out effective preventive efforts. © 2014 Japan Geriatrics Society.

Fracture Analyses of Cracked Delta Eye Plates in Ship Towing

Science.gov (United States)

Huang, Xiangbing; Huang, Xingling; Sun, Jizheng

2018-01-01

Based on fracture mechanics, a safety analysis approach is proposed for cracked delta eye plates in ship towing. The static analysis model is presented when the delta eye plate is in service, and the fracture criterion is introduced on basis of stress intensity factor, which is estimated with domain integral method. Subsequently, three-dimensional finite element analyses are carried out to obtain the effective stress intensity factors, and a case is studied to demonstrate the reasonability of the approach. The results show that the classical strength theory is not applicable to evaluate the cracked plate while fracture mechanics can solve the problem very well, and the load level, which a delta eye plate can carry on, decreases evidently when it is damaged.

Intrinsic and extrinsic risk factors for nonunion after nonoperative treatment of midshaft clavicle fractures.

Science.gov (United States)

Liu, W; Xiao, J; Ji, F; Xie, Y; Hao, Y

2015-04-01

The optimal treatment of midshaft clavicle fractures remains controversial. Nonunion is usually considered to be an uncommon complication following a nonoperatively treated clavicle fracture. Not every midshaft clavicular fractures shares the same risk of developing nonunion after nonoperative treatment. The present study was performed to identify the intrinsic and extrinsic independent factors that are independently predictive of nonunion in patients with midshaft clavicular fractures after nonoperative treatment. We performed a retrospective study of a series of 804 patients (391 men and 413 women with a median age of 51.3 years) with a radiographically confirmed midshaft clavicle fracture, which was treated nonoperatively. There were 96 patients who underwent nonunion. Putative intrinsic (patient-related) and extrinsic (injured-related) risk factors associated with nonunion were determined with the use of bivariate and multivariate statistical analyses. By bivariate analysis, the risk of nonunion was significantly increased by several intrinsic risk factors including age, sex, and smoking and extrinsic risk factors including displacement of the fracture and the presence of comminution (P<0.05 for all). On multivariate analysis, smoking (OR=4.16, 95% CI: 1.01-14.16), fracture displacement (OR=7.81, 95% CI: 2.27-25.38) and comminution of fracture (OR=3.86, 95% CI: 1.16-13.46) were identified as independent predictive factors. The risk factors for nonunion after nonoperative treatment of midshaft clavicle fractures are multifactorial. Smoking, fracture displacement and comminution of fracture are independent predictors for an individual likelihood of nonunion. Further studies are still required to evaluate these factors in the future. Level III, case-control study. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Evaluation of easily measured risk factors in the prediction of osteoporotic fractures

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Brown Jacques P

2005-09-01

Full Text Available Abstract Background Fracture represents the single most important clinical event in patients with osteoporosis, yet remains under-predicted. As few premonitory symptoms for fracture exist, it is of critical importance that physicians effectively and efficiently identify individuals at increased fracture risk. Methods Of 3426 postmenopausal women in CANDOO, 40, 158, 99, and 64 women developed a new hip, vertebral, wrist or rib fracture, respectively. Seven easily measured risk factors predictive of fracture in research trials were examined in clinical practice including: age (, 65–69, 70–74, 75–79, 80+ years, rising from a chair with arms (yes, no, weight (≥ 57kg, maternal history of hip facture (yes, no, prior fracture after age 50 (yes, no, hip T-score (>-1, -1 to >-2.5, ≤-2.5, and current smoking status (yes, no. Multivariable logistic regression analysis was conducted. Results The inability to rise from a chair without the use of arms (3.58; 95% CI: 1.17, 10.93 was the most significant risk factor for new hip fracture. Notable risk factors for predicting new vertebral fractures were: low body weight (1.57; 95% CI: 1.04, 2.37, current smoking (1.95; 95% CI: 1.20, 3.18 and age between 75–79 years (1.96; 95% CI: 1.10, 3.51. New wrist fractures were significantly identified by low body weight (1.71, 95% CI: 1.01, 2.90 and prior fracture after 50 years (1.96; 95% CI: 1.19, 3.22. Predictors of new rib fractures include a maternal history of a hip facture (2.89; 95% CI: 1.04, 8.08 and a prior fracture after 50 years (2.16; 95% CI: 1.20, 3.87. Conclusion This study has shown that there exists a variety of predictors of future fracture, besides BMD, that can be easily assessed by a physician. The significance of each variable depends on the site of incident fracture. Of greatest interest is that an inability to rise from a chair is perhaps the most readily identifiable significant risk factor for hip fracture and can be easily incorporated

Inclusion-initiated fracture model for ceramics

International Nuclear Information System (INIS)

Sung, J.; Nicholson, P.S.

1990-01-01

The fracture of ceramics initiating from a typical inclusion is analyzed. The inclusion is considered to have a thermal expansion coefficient and fracture toughness lower than those of the matrix and a Young's modulus higher than that of the matrix. Inclusion-initiated fracture is modeled for a spherical inclusion using a weight function method to compute the residual stress intensity factor for a part-through elliptical crack. The results are applied to an α-Al 2 O 3 inclusion embedded in a tetragonal ZrO 2 ceramic. The strength predictions agree well with experimental data

Probabilistic finite elements for fracture mechanics

Science.gov (United States)

Besterfield, Glen

1988-01-01

The probabilistic finite element method (PFEM) is developed for probabilistic fracture mechanics (PFM). A finite element which has the near crack-tip singular strain embedded in the element is used. Probabilistic distributions, such as expectation, covariance and correlation stress intensity factors, are calculated for random load, random material and random crack length. The method is computationally quite efficient and can be expected to determine the probability of fracture or reliability.

Prognostic Factors of Orbital Fractures with Muscle Incarceration

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Seung Chan Lee

2017-09-01

Full Text Available Background Among the various signs and symptoms of orbital fractures, certain clinical findings warrant immediate surgical exploration, including gaze restriction, computed tomographic (CT evidence of entrapment, and prolonged oculocardiac reflex. Despite proper surgical reconstruction, prolonged complications such as diplopia and gaze restriction can occur. This article evaluated the prognostic factors associated with prolonged complications of orbital fractures with muscle incarceration. Methods The medical records of 37 patients (37 orbits with an orbital fracture with muscle incarceration from January 2001 to January 2015 were reviewed. The presence of Incarcerated muscle was confirmed via CT, as well as by intraoperative findings. Various factors potentially contributing to complications lasting for over 1 year after the injury were categorized and analyzed, including age, cause of injury, injury-to-operation time, operative time, fracture type, nausea, vomiting and other concomitant symptoms and injuries. Results All patients who presented with extraocular muscle limitations, positive CT findings, and/or a positive forced duction test underwent surgery. Of the 37 patients, 9 (24% exhibited lasting complications, such as diplopia and gaze restriction. The mean follow-up period was 18.4 months (range, 1–108 months, while that of patients who experienced prolonged complications was 30.1 months (range, 13–36 months. Two factors were significantly associated with prolonged complications: injury-to-operation time and nausea/vomiting. Loss of vision, worsening of motility, and implant complication did not occur. Conclusions Patients who present with gaze limitations, with or without other signs of a blow-out fracture, require a thorough evaluation and emergent surgery. A better prognosis is expected with a shorter injury-to-operation time and lack of nausea and vomiting at the initial presentation.

Hip fracture epidemiological trends, outcomes, and risk factors, 1970–2009

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Ray Marks

2009-12-01

Full Text Available Ray MarksCity University of New York and Columbia University, New York, NY, USAAbstract: Hip fractures – which commonly lead to premature death, high rates of morbidity, or reduced life quality – have been the target of a voluminous amount of research for many years. But has the lifetime risk of incurring a hip fracture decreased sufficiently over the last decade or are high numbers of incident cases continuing to prevail, despite a large body of knowledge and a variety of contemporary preventive and refined surgical approaches? This review examines the extensive hip fracture literature published in the English language between 1980 and 2009 concerning hip fracture prevalence trends, and injury mechanisms. It also highlights the contemporary data concerning the personal and economic impact of the injury, plus potentially remediable risk factors underpinning the injury and ensuing disability. The goal was to examine if there is a continuing need to elucidate upon intervention points that might minimize the risk of incurring a hip fracture and its attendant consequences. Based on this information, it appears hip fractures remain a serious global health issue, despite some declines in the incidence rate of hip fractures among some women. Research also shows widespread regional, ethnic and diagnostic variations in hip fracture incidence trends. Key determinants of hip fractures include age, osteoporosis, and falls, but some determinants such as socioeconomic status, have not been well explored. It is concluded that while more research is needed, well-designed primary, secondary, and tertiary preventive efforts applied in both affluent as well as developing countries are desirable to reduce the present and future burden associated with hip fracture injuries. In this context, and in recognition of the considerable variation in manifestation and distribution, as well as risk factors underpinning hip fractures, well-crafted comprehensive, rather

Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.

Energy Technology Data Exchange (ETDEWEB)

Dadfarnia, Mohsen (University of Illinois at Urbana-Champaign, Urbana, IL); Nibur, Kevin A.; San Marchi, Christopher W.; Sofronis, Petros (University of Illinois at Urbana-Champaign, Urbana, IL); Somerday, Brian P.; Foulk, James W., III; Hayden, Gary A. (CP Industries, McKeesport, PA)

2010-07-01

Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} is the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.

Risk factors for stress fracture among young female cross-country runners.

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Kelsey, Jennifer L; Bachrach, Laura K; Procter-Gray, Elizabeth; Nieves, Jeri; Greendale, Gail A; Sowers, Maryfran; Brown, Byron W; Matheson, Kim A; Crawford, Sybil L; Cobb, Kristin L

2007-09-01

To identify risk factors for stress fracture among young female distance runners. Participants were 127 competitive female distance runners, aged 18-26, who provided at least some follow-up data in a randomized trial among 150 runners of the effects of oral contraceptives on bone health. After completing a baseline questionnaire and undergoing bone densitometry, they were followed an average of 1.85 yr. Eighteen participants had at least one stress fracture during follow-up. Baseline characteristics associated (Pstress fracture occurrence were one or more previous stress fractures (rate ratio [RR] [95% confidence interval]=6.42 (1.80-22.87), lower whole-body bone mineral content (RR=2.70 [1.26-5.88] per 1-SD [293.2 g] decrease), younger chronologic age (RR=1.42 [1.05-1.92] per 1-yr decrease), lower dietary calcium intake (RR=1.11 [0.98-1.25] per 100-mg decrease), and younger age at menarche (RR=1.92 [1.15-3.23] per 1-yr decrease). Although not statistically significant, a history of irregular menstrual periods was also associated with increased risk (RR=3.41 [0.69-16.91]). Training-related factors did not affect risk. The results of this and other studies indicate that risk factors for stress fracture among young female runners include previous stress fractures, lower bone mass, and, although not statistically significant in this study, menstrual irregularity. More study is needed of the associations between stress fracture and age, calcium intake, and age at menarche. Given the importance of stress fractures to runners, identifying preventive measures is of high priority.

Fracture toughness testing of a reactor grade graphite

Energy Technology Data Exchange (ETDEWEB)

Roeding, M.; Klein, G.; Schiffers, H.; Nickel, H.

1976-03-15

Fracture mechanics is a well established tool for the assessment of brittle fracture in metallic structural materials. In this paper an attempt is made to apply fracture mechanics to a reactor-grade graphite. The effect of several test parameters on the stress intensity factor was measured; this was found to lie in the range 25 and 50 N/mm/sup -3/2/. The results are discussed in terms of the well known mechanical characteristics of graphite.

Ketamine as an Analgesic Adjuvant in Adult Trauma Intensive Care Unit Patients With Rib Fracture.

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Walters, Mary K; Farhat, Joseph; Bischoff, James; Foss, Mary; Evans, Cory

2018-03-01

Rib fracture associated pain is difficult to control. There are no published studies that use ketamine as a therapeutic modality to reduce the amount of opioid to control rib fracture pain. To examine the analgesic effects of adjuvant ketamine on pain scale scores in trauma intensive care unit (ICU) rib fracture. This retrospective, case-control cohort chart review evaluated ICU adult patients with a diagnosis of ≥1 rib fracture and an Injury Severity Score >15 during 2016. Patients received standard-of-care pain management with the physician's choice analgesics with or without ketamine as a continuous, fixed, intravenous infusion at 0.1 mg/kg/h. A total of 15 ketamine treatment patients were matched with 15 control standard-of-care patients. Efficacy was measured via Numeric Pain Scale (NPS)/Behavioral Pain Scale (BPS) scores, opioid use, and ICU and hospital length of stay. Safety of ketamine was measured by changes in vital signs, adverse effects, and mortality. Average NPS/BPS, severest NPS/BPS, and opioid use were lower in the ketamine group than in controls (NPS: 4.1 vs 5.8, P rib fracture.

Risk Factors for First Fractures Among Males With Duchenne or Becker Muscular Dystrophy.

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James, Katherine A; Cunniff, Christopher; Apkon, Susan D; Mathews, Katherine; Lu, Zhenqiang; Holtzer, Caleb; Pandya, Shree; Ciafaloni, Emma; Miller, Lisa

2015-09-01

Fractures are a significant concern for individuals with Duchenne/Becker muscular dystrophy with 21% to 44% of males experiencing a fracture. Factors that increase or decrease the risk for fracture have been suggested in past research, although statistical risk has not been determined. In this retrospective cohort study, we used the Muscular Dystrophy Surveillance, Tracking and Research Network cohort, a large, population-based sample to identify risk factors associated with first fractures in patients with Duchenne or Becker muscular dystrophy. Our study cohort included males with Duchenne or Becker muscular dystrophy born between 1982 and 2006 who resided in Arizona, Colorado, Georgia, Iowa, and Western New York, retrospectively identified and followed through 2010. We utilized a multivariate Cox proportional hazard model to determine hazard ratios for relevant factors associated with first fracture risk including race/ethnicity, surveillance site, ambulation status, calcium/vitamin D use and duration, bisphosphonate use and duration, and corticosteroid use and duration. Of 747 cases, 249 had at least 1 fracture (33.3%). Full-time wheelchair use increased the risk of first fracture by 75% for every 3 months of use (hazard ratio=1.75, 95% confidence interval, 1.14, 2.68), but corticosteroid use, bisphosphonate use, and calcium/vitamin D use did not significantly affect risk in the final adjusted model. In this cohort, first fractures were common and full-time wheelchair use, but not corticosteroid use, was identified as a risk factor. The impact of prevention measures should be more thoroughly assessed. Fractures are a significant concern for individuals with dystrophinopathies, but the contribution of various risk factors has not been consistently demonstrated.

Poverty is a risk factor for osteoporotic fractures.

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Navarro, M C; Sosa, M; Saavedra, P; Lainez, P; Marrero, M; Torres, M; Medina, C D

2009-03-01

the lumbar spine, and a higher prevalence of densitometric osteoporosis, and a higher prevalence of total and vertebral fractures. Because of this, apart from the well known risk factors for osteoporosis, poverty should be taken into account as a possible risk factor for both osteoporosis and fragility fractures, in order to establish sanitary strategies to protect unfavoured postmenopausal women.

Rib fractures after reirradiation plus hyperthermia for recurrent breast cancer. Predictive factors

International Nuclear Information System (INIS)

Oldenborg, Sabine; Valk, Christel; Os, Rob van; Voerde Sive Voerding, Paul zum; Crezee, Hans; Tienhoven, Geertjan van; Rasch, Coen; Oei, Bing; Venselaar, Jack; Randen, Adrienne van

2016-01-01

Combining reirradiation (reRT) and hyperthermia (HT) has shown high therapeutic value for patients with locoregional recurrent breast cancer (LR). However, additional toxicity of reirradiation (e.g., rib fractures) may occur. The aim of this study is to determine the impact of potential risk factors on the occurrence of rib fractures. From 1982-2005, 234 patients were treated with adjuvant reRT + HT after surgery for LR. ReRT consisted typically of 8 fractions of 4 Gy twice a week, or 12 fractions of 3 Gy four times a week. A total of 118 patients were irradiated with abutted photon and electron fields. In all, 60 patients were irradiated using either one or alternating combinations of abutted AP electron fields. Hyperthermia was given once or twice a week. The 5-year infield local control (LC) rate was 70 %. Rib fractures were detected in 16 of 234 patients (actuarial risk: 7 % at 5 years). All rib fractures occurred in patients treated with a combination of photon and abutted electron fields (p = 0.000); in 15 of 16 patients fractures were located in the abutment regions. The other significant predictive factors for rib fractures were a higher fraction dose (p = 0.040), large RT fields, and treatment before the year 2000. ReRT + HT results in long-term LC. The majority of rib fractures were located in the photon/electron abutment area, emphasizing the disadvantage of field overlap. Large abutted photon/electron fields combined with 4 Gy fractions increase the number of rib fractures in this study group. However, as these factors were highly correlated no relative importance of the individual factors could be estimated. Increasing the number of HT sessions a week does not increase the risk of rib fractures. (orig.) [de

Risk factors for fractures in patients with rheumatoid arthritis (preliminary results of the multicenter program «Osteoporosis in rheumatoid arthritis: Diagnosis, risk factors, fractures, treatment»

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Marina Mikhailovna Podvorotova

2013-01-01

Full Text Available In patients with rheumatoid arthritis (RA, bone fractures occur 1.5-2 times more frequently than in the population. They often lead to reduced quality of life, to disability and death in the patients. It should be noted that risk factors (RFs for fractures have not been studied on a sufficient sample in Russia; there are no recommendations on the prevention of fractures in this category of patients. Objective: to compare groups of RA patients with and without a history of fractures to further identify possible RFs for fractures. Subjects and methods. The trial included 254 patients aged 18 to 85 years, diagnosed with RA, from the database of the multicenter program «Osteoporosis in rheumatoid arthritis: Diagnosis, risk factors, fractures, treatment», who had been followed up in 2010 to 2011. The patients were divided into two groups: 1 101 (39.8% patients with a history of low-trauma fractures and 2 153 (60.2% patients without a history of fractures. In Group 1, the patients were older than in Group 2 (mean age 59.8 and 56.1 years, respectively. Menopause was recorded in 88.1 and 77.8% of cases, respectively. The groups differed in the duration of RA an average of 15.5 and 11.5 years, respectively Results. The fractures in the history were associated with the use of glucocorticoids (GC, their higher cumulative dose and use duration. In Group 1 patients, the bone mineral density (BMD was lower in all study skeleton portions and more frequently corresponded to osteoporosis. RA complications, such as amyloidosis and osteonecrosis, were more common in the patients with a history of fractures. Conclusion. In RA patients, the most likely RFs of fractures are age, the long-term intake of large-dose GC, low BMD, the severe course of RA, and the presence of its complications.

Recombinant human parathyroid hormone (PTH 1-34) and low-intensity pulsed ultrasound have contrasting additive effects during fracture healing.

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Warden, Stuart J; Komatsu, David E; Rydberg, Johanna; Bond, Julie L; Hassett, Sean M

2009-03-01

Fracture healing is thought to be naturally optimized; however, recent evidence indicates that it may be manipulated to occur at a faster rate. This has implications for the duration of morbidity associated with bone injuries. Two interventions found to accelerate fracture healing processes are recombinant human parathyroid hormone [1-34] (PTH) and low-intensity pulsed ultrasound (LIPUS). This study aimed to investigate the individual and combined effects of PTH and LIPUS on fracture healing. Bilateral midshaft femur fractures were created in Sprague-Dawley rats, and the animals treated 7 days/week with PTH (10 microg/kg) or a vehicle solution. Each animal also had one fracture treated for 20 min/day with active-LIPUS (spatial-averaged, temporal-averaged intensity [I(SATA)]=100 mW/cm(2)) and the contralateral fracture treated with inactive-LIPUS (placebo). Femurs were harvested 35 days following injury to permit micro-computed tomography, mechanical property and histological assessments of the fracture calluses. There were no interactions between PTH and LIPUS indicating that their effects were additive rather than synergistic. These additive effects were contrasting with LIPUS primarily increasing total callus volume (TV) without influencing bone mineral content (BMC), and PTH having the opposite effect of increasing BMC without influencing TV. As a consequence of the effect of LIPUS on TV but not BMC, it decreased volumetric bone mineral density (vBMD) resulting in a less mature callus. The decreased maturity and persistence of cartilage at the fracture site when harvested offset any beneficial mechanical effects of the increased callus size with LIPUS. In contrast, the effect of PTH on callus BMC but not TV resulted in increased callus vBMD and a more mature callus. This resulted in PTH increasing fracture site mechanical strength and stiffness. These data suggest that PTH may have utility in the treatment of acute bone fractures, whereas LIPUS at an I(SATA) of

Laplace-SGBEM analysis of the dynamic stress intensity factors and the dynamic T-stress for the interaction between a crack and auxetic inclusions

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Kwon, Kibum

A dynamic analysis of the interaction between a crack and an auxetic (negative Poisson ratio)/non-auxetic inclusion is presented. The two most important fracture parameters, namely the stress intensity factors and the T-stress are analyzed by using the symmetric Galerkin boundary element method in the Laplace domain for three different models of crack-inclusion interaction. To investigate the effects of auxetic inclusions on the fracture behavior of composites reinforced by this new type of material, comparisons of the dynamic stress intensity factors and the dynamic T-stress are made between the use of auxetic inclusions as opposed to the use of traditional inclusions. Furthermore, the technique presented in this research can be employed to analyze for the interaction between a crack and a cluster of auxetic/non-auxetic inclusions. Results from the latter models can be employed in crack growth analysis in auxetic-fiber-reinforced composites.

Risk factors of neurological lesions in low cervical spine fractures and dislocations

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COELHO DANILO GONÇALVES

2000-01-01

Full Text Available Eighty-nine patients with lower cervical spine fractures or dislocations were evaluated for risk factors of neurological lesion. The age, sex, level and pattern of fracture and sagittal diameter of the spinal canal were analysed. There were no significant differences on the age, gender, level and Torg's ratio between intact patients and those with nerve root injury, incomplete or complete spinal cord injuries. Bilateral facet dislocations and burst fractures are a significant risk factor of spinal cord injury.

Risk Factors for Hip Fracture in Older Home Care Clients

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Poss, Jeff; Cook, Richard J.; Byrne, Kerry; Hirdes, John P.

2009-01-01

Background Little information is available on hip fracture risks among community-dwelling persons receiving home care. Our aim was to identify risk factors for hip fracture from health information routinely collected for older home care clients. Methods This was a cohort study involving secondary analysis of data on 40,279 long-stay (>60 days) home care clients aged 65 and older in Ontario, Canada; occurrence of hip fracture as well as potential risk factor information were measured using the Resident Assessment Instrument (RAI)/Minimum Data Set–Home Care assessment instrument. Results In all, 1,003 clients (2.5%) had hip fracture on follow-up assessment. Older (85+ vs 65–74, relative risk [95% confidence interval]: 0.52 [0.43–0.64]) clients are at increased risk; males are at reduced risk [0.60 (0.51–0.70)]. Other risk factors include osteoporosis (1.19 [1.03–1.36]), falls (1.31 [1.15–1.49]), unsteady gait (1.18 [1.03–1.36]), use of ambulation aide (1.39 [1.21–1.59]), tobacco use (1.42, [1.13–1.80]), severe malnutrition (2.61 [1.67–4.08]), and cognitive impairment (1.30 [1.12–1.51]). Arthritis (0.86 [0.76–0.98]) and morbid obesity (0.34 [0.16–0.72]) were associated with reduced risk. Males and females demonstrated different risk profiles. Conclusions Important risk factors for hip fracture can be identified from routinely collected data; these could be used to identify at-risk clients for further investigation and prevention strategies [22]. PMID:19196903

Various methods of numerical estimation of generalized stress intensity factors of bi-material notches

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Klusák J.

2009-12-01

Full Text Available The study of bi-material notches becomes a topical problem as they can model efficiently geometrical or material discontinuities. When assessing crack initiation conditions in the bi-material notches, the generalized stress intensity factors H have to be calculated. Contrary to the determination of the K-factor for a crack in an isotropic homogeneous medium, for the ascertainment of the H-factor there is no procedure incorporated in the calculation systems. The calculation of these fracture parameters requires experience. Direct methods of estimation of H-factors need choosing usually length parameter entering into calculation. On the other hand the method combining the application of the reciprocal theorem (Ψ-integral and FEM does not require entering any length parameter and is capable to extract the near-tip information directly from the far-field deformation.

[Association between hip fractures and risk factors for osteoporosis. Multivariate analysis].

Science.gov (United States)

Masoni, Ana; Morosano, Mario; Tomat, María Florencia; Pezzotto, Stella M; Sánchez, Ariel

2007-01-01

In this observational, case-control study, 376 inpatients were evaluated in order to determine the association of risk factors (RF) and hip fracture; 151 patients had osteoporotic hip fracture (cases); the remaining were controls. Data were obtained from medical charts, and through a standardized questionnaire about RF. Mean age of the sample (+/- SD) was 80.6 +/- 8.1 years, without statistically significant difference between cases and controls; the female:male ratio was 3:1 in both groups. Fractured women were older than men (82.5 +/- 8.1 vs. 79.7 +/- 7.2 years, respectively; p household duties was a RF (p = 0.007), which was absent in males. In multivariate analysis, the following RF were significantly more frequent: Cognitive impairment (p = 0.001), and previous falls (p < 0.0001); whereas the following protective factors were significantly different from controls: Calcium intake during youth (p < 0.0001), current calcium intake (p < 0.0001), and mechanical aid for walking (p < 0.0001). Evaluation of RF and protective factors may contribute to diminish the probability of hip fracture, through a modification of personal habits, and measures to prevent falls among elderly adults. Present information can help to develop local and national population-based strategies to diminish the burden of hip fractures for the health system.

Factors leading to tracheobronchial self-expandable metallic stent fracture.

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Chung, Fu-Tsai; Lin, Shu-Min; Chen, Hao-Cheng; Chou, Chun-Liang; Yu, Chih-Teng; Liu, Chien-Ying; Wang, Chun-Hua; Lin, Horng-Chyuan; Huang, Chien-Da; Kuo, Han-Pin

2008-11-01

This retrospective study was to determine factors that contribute to self-expandable metallic stent fracture in patients with tracheobronchial disease. From 2001 to 2006, 139 patients (age, 62.1 +/- 15.4 years; range, 23-87 years) with benign (n = 62) and malignant (n = 77) tracheobronchial disease received 192 Ultraflex (Boston Scientific, Natick, Mass) self-expandable metallic stents (98 in patients with benign disease and 94 in patients with malignant disease). Seventeen fractured self-expandable metallic stents were found; the incidence was 12.2% (17/139 patients) among patients with tracheobronchial disease. Tortuous airway (odds ratio, 4.06; 95% confidence interval, 1.04-18.34; P = .04) independently predicted self-expandable metallic stent fracture. Most self-expandable metallic stent fractures (64.7%, 11/17) were detected 500 to 1000 days after self-expandable metallic stent implantation. Clinical presentations for patients with fractured self-expandable metallic stents included dyspnea exacerbation (70.6%, 12/17) and cough (23.5%, 4/17). Self-expandable metallic stent fracture is not uncommon in patients with tracheobronchial disease. Tortuous airway is an independent predictor for it. Although management of the fractured self-expandable metallic stent in our study was feasible and safe, self-expandable metallic stents should be restricted to a more select population.

Characterising rock fracture aperture-spacing relationships using power-law relationships: some considerations

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Brook, Martin; Hebblewhite, Bruce; Mitra, Rudrajit

2016-04-01

The size-scaling of rock fractures is a well-studied problem in geology, especially for permeability quantification. The intensity of fractures may control the economic exploitation of fractured reservoirs because fracture intensity describes the abundance of fractures potentially available for fluid flow. Moreover, in geotechnical engineering, fractures are important for parameterisation of stress models and excavation design. As fracture data is often collected from widely-spaced boreholes where core recovery is often incomplete, accurate interpretation and representation of fracture aperture-frequency relationships from sparse datasets is important. Fracture intensity is the number of fractures encountered per unit length along a sample scanline oriented perpendicular to the fractures in a set. Cumulative frequency of fractures (F) is commonly related to fracture aperture (A) in the form of a power-law (F = aA-b), with variations in the size of the a coefficient between sites interpreted to equate to fracture frequency for a given aperture (A). However, a common flaw in this approach is that even a small change in b can have a large effect on the response of the fracture frequency (F) parameter. We compare fracture data from the Late Permian Rangal Coal Measures from Australia's Bowen Basin, with fracture data from Jurassic carbonates from the Sierra Madre Oriental, northeastern Mexico. Both power-law coefficient a and exponent b control the fracture aperture-frequency relationship in conjunction with each other; that is, power-laws with relatively low a coefficients have relatively high b exponents and vice versa. Hence, any comparison of different power-laws must take both a and b into consideration. The corollary is that different sedimentary beds in the Sierra Madre carbonates do not show ˜8× the fracture frequency for a given fracture aperture, as based solely on the comparison of coefficient a. Rather, power-law "sensitivity factors" developed from both

The science of ultrasound therapy for fracture healing

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Della Rocca Gregory

2009-01-01

Full Text Available Fracture healing involves a complex interplay of cellular processes, culminating in bridging of a fracture gap with bone. Fracture healing can be compromised by numerous exogenous and endogenous patient factors, and intense research is currently going on to identify modalities that can increase the likelihood of successful healing. Low-intensity pulsed ultrasound (LIPUS has been proposed as a modality that may have a benefit for increasing reliable fracture healing as well as perhaps increasing the rate of fracture healing. We conducted a review to establish basic scince evidence of therapeutic role of lipus in fracture healing. An electronic search without language restrictions was accomplished of three databases (PubMed, Embase, Cinahl for ultrasound-related research in osteocyte and chondrocyte cell culture and in animal fracture models, published from inception of the databases through December, 2008. Studies deemed to be most relevant were included in this review. Multiple in vitro and animal in vivo studies were identified. An extensive body of literature exists which delineates the mechanism of action for ultrasound on cellular and tissue signaling systems that may be related to fracture healing. Research on LIPUS in animal fracture models has demonstrated promising results for acceleration of fracture healing and for promotion of fracture healing in compromised tissue beds. A large body of cellular and animal research exists which reveals that LIPUS may be beneficial for accelerating normal fracture healing or for promoting fracture healing in compromised tissue beds. Further investigation of the effects of LIPUS in human fracture healing is warranted for this promising new therapy.

The maximum possible stress intensity factor for a crack in an unknown residual stress field

International Nuclear Information System (INIS)

Coules, H.E.; Smith, D.J.

2015-01-01

Residual and thermal stress fields in engineering components can act on cracks and structural flaws, promoting or inhibiting fracture. However, these stresses are limited in magnitude by the ability of materials to sustain them elastically. As a consequence, the stress intensity factor which can be applied to a given defect by a self-equilibrating stress field is also limited. We propose a simple weight function method for determining the maximum stress intensity factor which can occur for a given crack or defect in a one-dimensional self-equilibrating stress field, i.e. an upper bound for the residual stress contribution to K I . This can be used for analysing structures containing defects and subject to residual stress without any information about the actual stress field which exists in the structure being analysed. A number of examples are given, including long radial cracks and fully-circumferential cracks in thick-walled hollow cylinders containing self-equilibrating stresses. - Highlights: • An upper limit to the contribution of residual stress to stress intensity factor. • The maximum K I for self-equilibrating stresses in several geometries is calculated. • A weight function method can determine this maximum for 1-dimensional stress fields. • Simple MATLAB scripts for calculating maximum K I provided as supplementary material.

Measurements of interface fracture properties of composite materials

International Nuclear Information System (INIS)

Ashkenazi, D.; Bank-Sills, L.; Travitzky, N.; Eliasi, R.

1998-01-01

In this investigation, interface Fracture properties are measured. To this end, glass/epoxy Brazilian disk specimens are studied. In order to calibrate the specimen, a numerical procedure is used. The finite element method is employed to derive stress intensity factors as a function of loading angle and crack length. By means of the weight friction method together with finite elements, a correction to the stress intensity factors for residual thermal stresses is obtained. These are combined to determine the critical interface energy release rate as a function of phase angle Tom the measured load and crack length at Fracture. A series of tests on a glass/epoxy material pair were carried out. It may be observed from the results that the residual thermal stresses resulting from the material mismatch greatly affect the interface toughness values

Risk factors for hip fracture in elderly persons

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P. Olivi

2011-06-01

Full Text Available Objective: The aim of this observational study, promoted by the Health Authorities of the Regione Veneto (Italy, is to assess the prevalence of the most relevant environmental and individual risk factors in subjects with a recent hip fracture. Methods: Patients aged more than 60 years of both genders with a recent hip fracture not associated with malignancies, were administered questionnaires on dietary habits, sun exposure, and disability score. A complete family, pharmacological and pathology history was collected together with information on previous falls, details of the fracture index, and anthropometric data. In all subjects, blood was taken for the measurement of serum 25 hydroxy-vitamin D (25OHD. Results: The study included 704 patients (573 women and 131 men. Mean age was 81±8 years (range 60-102. Severe pre-fracture disability was a common feature (58% associated with multiple co-morbidities (84%, more frequently cardio- vascular and neurological diseases, and specific medications. In a large proportion (86% of the patients, environmental or individual risk factors for falling were found. Vitamin D insufficiency (serum 25OHD levels <75 nmol/l was quite common (70%, particularly in the regional Health Districts were strategies for preventing vitamin D deficiency were not implemented (91%. Only a small proportion (17% of the study population had been evaluated and treated for osteoporosis. Conclusions: In senile patients with a recent hip fracture, pre-existing disability, multiple co-morbidities, high risk of falling and inadequate intake of calcium and vitamin D is relatively common. Community and case-finding interventions aimed at selecting subjects at high risk of osteoporosis, preventing vitamin D and dietary calcium deficiency, and increasing awareness on the environmental risks of falling are highly warranted.

Clinical and Radiologic Predictive Factors of Rib Fractures in Outpatients With Chest Pain.

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Zhang, Liang; McMahon, Colm J; Shah, Samir; Wu, Jim S; Eisenberg, Ronald L; Kung, Justin W

To identify the clinical and radiologic predictive factors of rib fractures in stable adult outpatients presenting with chest pain and to determine the utility of dedicated rib radiographs in this population of patients. Following Institutional Review Board approval, we performed a retrospective review of 339 consecutive cases in which a frontal chest radiograph and dedicated rib series had been obtained for chest pain in the outpatient setting. The frontal chest radiograph and dedicated rib series were sequentially reviewed in consensus by two fellowship-trained musculoskeletal radiologists blinded to the initial report. The consensus interpretation of the dedicated rib series was used as the gold standard. Multiple variable logistic regression analysis assessed clinical and radiological factors associated with rib fractures. Fisher exact test was used to assess differences in medical treatment between the 2 groups. Of the 339 patients, 53 (15.6%) had at least 1 rib fracture. Only 20 of the 53 (37.7%) patients' fractures could be identified on the frontal chest radiograph. The frontal chest radiograph had a sensitivity of 38% and specificity of 100% when using the rib series as the reference standard. No pneumothorax, new mediastinal widening or pulmonary contusion was identified. Multiple variable logistic regression analysis of clinical factors associated with the presence of rib fractures revealed a significant association of trauma history (odds ratio 5.7 [p rib fractures in this population demonstrated a significant association of pleural effusion with rib fractures (odds ratio 18.9 [p rib fractures received narcotic analgesia in 47.2% of the cases, significantly more than those without rib fractures (21.3%, p rib fractures have a higher association with a history of minor trauma and age ≥40 in the adult population. Radiographic findings associated with rib fractures include pleural effusion. The frontal chest radiograph alone has low sensitivity in

[Effect factors analysis of knee function recovery after distal femoral fracture operation].

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Bei, Chaoyong; Wang, Ruiying; Tang, Jicun; Li, Qiang

2009-09-01

To investigate the effect factors of knee function recovery after operation in distal femoral fractures. From January 2001 to May 2007, 92 cases of distal femoral fracture were treated. There were 50 males and 42 females, aged 20-77 years old (average 46.7 years old). Fracture was caused by traffic accident in 48 cases, by falling from height in 26 cases, by bruise in 12 cases and by tumble in 6 cases. According to Müller's Fracture classification, there were 29 cases of type A, 12 cases of type B and 51 cases of type C. According to American Society of Anesthesiologists (ASA) classification, there were 21 cases of grade I, 39 cases of grade II, 24 cases of grade III, and 8 cases of grade IV. The time from injury to operation was 4 hours to 24 days with an average of 7 days. Anatomical plate was used in 43 cases, retrograde interlocking intramedullary nail in 37 cases, and bone screws, bolts and internal fixation with Kirschner pins in 12 cases. After operation, the HSS knee function score was used to evaluate efficacy. Ten related factors were applied for statistical analysis, to knee function recovery after operation in distal femoral fractures, such as age, sex, preoperative ASA classification, injury to surgery time, fracture type, treatment, reduction quality, functional exercise after operation, whether or not CPM functional training and postoperative complications. Wound healed by first intention in 88 cases, infection occurred in 4 cases. All patients followed up 16-32 months with an average of 23.1 months. Clinical union of fracture was achieved within 3-7 months after operation. Extensor device adhesions and the scope of activities of fracture displacement in 6 cases, mild knee varus or valgus in 7 cases and implant loosening in 6 cases. According to HSS knee function score, the results were excellent in 52 cases, good in 15 cases, fair in 10 cases and poor in 15 cases with an excellent and good rate of 72.83%. Single factor analysis showed that age

Fracture Testing with Surface Crack Specimens. [especially the residual tensile strength test

Science.gov (United States)

Orange, T. W.

1974-01-01

Recommendations are given for the design, preparation, and static fracture testing of surface crack specimens. The recommendations are preceded by background information including discussions of stress intensity factors, crack opening displacements, and fracture toughness values associated with surface crack specimens. Cyclic load and sustained load tests are discussed briefly.

Mandible Fracture Complications and Infection: The Influence of Demographics and Modifiable Factors.

Science.gov (United States)

Odom, Elizabeth B; Snyder-Warwick, Alison K

2016-08-01

Mandible fractures account for 36 to 70 percent of all facial fractures. Despite their high prevalence, the literature lacks a comprehensive review of demographics, fracture patterns, timing of management, antibiotic selection, and outcomes, particularly when evaluating pediatric versus adult patients. The authors aim to determine the complication and infection rates after surgical treatment of mandibular fractures and the bacterial isolates and antibiotic sensitivities from mandible infections after open reduction and internal fixation at their institution. Data were collected retrospectively for all mandible fractures treated at the authors' institution between 2003 and 2013. Patients were divided into pediatric (younger than 16 years) and adult (16 years or older) subgroups. Demographics, fracture location, fracture cause, comorbidities, antibiotic choice, and subsequent complications and infections were analyzed. Data were evaluated using appropriate statistical tests for each variable. Three hundred ninety-five patients were evaluated. Demographics and fracture cause were similar to those reported in current literature. Of the 56 pediatric patients, complications occurred in 5.6 percent. Time from injury to operative intervention did not affect outcome. The complication rate was 17.5 percent and the infection rate was 9.4 percent in the adult subgroup. Time from injury to operative intervention, sex, and edentulism were not significant predictors of complication or infection. Tobacco use, number of fractures, number of fractures fixated, and surgical approach were predictors of complication and infection. Perioperative ampicillin-sulbactam had a significantly lower risk of infection. Certain demographic and operative factors lead to significantly higher risks of complications after surgical management of mandibular fractures. Ampicillin-sulbactam provides effective antibiotic prophylaxis. Risk factor modification may improve outcomes. Risk, IV.

Mode II brittle fracture: recent developments

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A. Campagnolo

2017-10-01

Full Text Available Fracture behaviour of V-notched specimens is assessed using two energy based criteria namely the averaged strain energy density (SED and Finite Fracture Mechanics (FFM. Two different formulations of FFM criterion are considered for fracture analysis. A new formulation for calculation of the control radius Rc under pure Mode II loading is presented and used for prediction of fracture behaviour. The critical Notch Stress Intensity Factor (NSIF at failure under Mode II loading condition can be expressed as a function of notch opening angle. Different formulations of NSIFs are derived using the three criteria and the results are compared in the case of sharp V-notched brittle components under in-plane shear loading, in order to investigate the ability of each method for the fracture assessment. For this purpose, a bulk of experimental data taken from the literature is employed for the comparison among the mentioned criteria

Prediction of brittle fracture of epoxy-aluminum flanging

Directory of Open Access Journals (Sweden)

Korbel J.

2010-07-01

Full Text Available This paper presents a fracture mechanical approach for estimation of critical bending load of different types of aluminum-epoxy flanging and comparison with experimental measurements. For this purpose, several designs of the flanges were investigated. The flanges were glued to the epoxy bars and adhesive-epoxy interface was considered as a bi-material notch. Prediction of the failure is based on generalized stress intensity factor and generalized fracture toughness.

Factors associated with union time of acute middle-third scaphoid fractures: an observational study

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Zhao H

2018-06-01

Full Text Available Hongfang Zhao,* Siyu Tian,* Lingde Kong,* Jiangbo Bai,* Jian Lu, Bing Zhang, Dehu Tian Department of Orthopedics, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei 050051, People’s Republic of China *These authors contributed equally to this work Background: The aim of this study was to investigate the union time of acute middle-third scaphoid fractures following treatments and to analyze the effect of different factors on late union.Patients and methods: We retrospectively reviewed patients with acute middle-third scaphoid fracture at our institution between January 2013 and December 2017. Patient demographics, fracture characteristics, and treatment strategy, such as age, gender, body mass index, habit of smoking, sides of injury, dominant hand, ulnar variance, multiple fractures, and treatment methods, were investigated. Univariate and multivariate analyses were used to identify possible predictive factors.Results: A total of 132 patients with scaphoid fracture were included in our study. Operation was performed in 67 patients (50.8%, and conservative treatment was performed in the other 65 patients (49.2%. The union time was 7.2±0.5 weeks. In the multivariate logistic regression analysis, late diagnosis (odds ratio, 1.247; 95% CI, 1.022–1.521 and conservative treatment method (odds ratio, 1.615; 95% CI, 1.031–2.528 were identified as 2 independent predictors of late union in scaphoid fractures patients. Other parameters were not demonstrated to be predictive factors.Conclusion: Late diagnosis and conservative treatment were two factors associated with late union. Long time of follow-up is necessary for patient with these factors. Keywords: predictive factors, union time, nonunion, scaphoid fractures, multivariable analysis

A review of lifestyle, smoking and other modifiable risk factors for osteoporotic fractures

DEFF Research Database (Denmark)

Abrahamsen, Bo; Brask-Lindemann, Dorthe; Rubin, Katrine Hass

2014-01-01

Although many strong risk factors for osteoporosis-such as family history, fracture history and age-are not modifiable, a number of important risk factors are potential targets for intervention. Thus, simple, non-pharmacological intervention in patients at increased risk of osteoporotic fractures...... could include reduction of excessive alcohol intake, smoking cessation, adequate nutrition, patient education, daily physical activity and a careful review of medications that could increase the risk of falls and fractures. There remains, however, an unmet need for high-quality intervention studies...

[Comparison of clinical effectiveness of thoracic epidural and intravenous patient-controlled analgesia for the treatment of rib fractures pain in intensive care unit].

Science.gov (United States)

Topçu, Ismet; Ekici, Zeynep; Sakarya, Melek

2007-07-01

The results of thoracic epidural and systemic patient controlled analgesia practice were evaluated retrospectively in patients with thoracic trauma. Patients who were admitted to the intensive care unit between 1997 and 2003, with a diagnosis of multiple rib fractures related to thoracic trauma were evaluated retrospectively. Data were recorded from 49 patients who met the following criteria; three or more rib fractures, initiation of PCA with I.V. phentanyl or thoracic epidural analgesia with phentanyl and bupivacaine. There were no significant differences between the groups concerning injury severity score. APACHE II score (8.1+/-1.6 and 9.2+/-1.7) and the number of rib fractures (4+/-1.1 and 6.8+/-2.7) were higher in thoracic epidural analgesia group (pPain scores of patients who received thoracic epidural analgesia were significantly lower as from 6th hour during whole therapy (prib fractures who require intensive care.

Thermal stress intensity factor for an axial crack in a clad cylinder

International Nuclear Information System (INIS)

Kuo, An Yu; Deardorf, A.F.; Riccardella, P.C.

1993-01-01

Many clad pressure vessels have been found to have cracks running through the inside surface cladding and into the base material. Although Young's moduli and Poisson's ratios of the clad and base materials are about the same for most of the industrial applications, coefficients of thermal expansion of the two dissimilar materials, clad and base materials, are usually quite different. For example, low alloy ferritic steel is a common base material for reactor pressure vessels (RPV) and the vessels are usually clad with austenitic stainless steel. Young's moduli for the low alloy steel and stainless steel at 350 F are 29,000 ksi and 28,000 ksi, respectively, while their coefficients of thermal expansion are 7.47x10 -6 in/in and 9.50x10 -6 in/in-degree F, respectively. The mismatch in coefficients of thermal expansion will cause high residual thermal stress even when the entire vessel is at a uniform temperature. This residual stress is one of the primary reasons why so many cracks have been found in the cladded components. In performing reactor pressure vessel integrity evaluation, such as computing probability of brittle fracture of the RPV, it is necessary to calculate stress intensity factors for cracks, which initiate from the clad material and run into the base metal. This paper presents a convenient method of calculating stress intensity factor for an axial crack emanating from the inside surface of a cladded cylinder under thermal loading. A J-integral like line integral was derived and used to calculate the stress intensity factors from finite element stress solutions of the problem

Generalized linear elastic fracture mechanics: an application to a crack touching the bimaterial interface

Czech Academy of Sciences Publication Activity Database

Náhlík, Luboš; Šestáková, L.; Hutař, Pavel; Knésl, Zdeněk

2011-01-01

Roč. 452-453, - (2011), s. 445-448 ISSN 1013-9826 R&D Projects: GA AV ČR(CZ) KJB200410803; GA ČR GA101/09/1821 Institutional research plan: CEZ:AV0Z20410507 Keywords : generalized stress intensity factor * bimaterial interface * composite materials * strain energy density factor * fracture criterion * generalized linear elastic fracture mechanics Subject RIV: JL - Materials Fatigue, Friction Mechanics

Expression of various growth factors for cell proliferation and cytodifferentiation during fracture repair of bone

Directory of Open Access Journals (Sweden)

M Fukuda

2009-12-01

Full Text Available We examined immunohistochemically the fracture repair process in rat tibial bone using antibodies to PCNA, BMP2, TGF-b 1,-2,-3, TGF-b R1,- R2, bFGF, bFGFR, PDGF, VEGF, and S-100. The peak level of cell proliferation as revealed by PCNA labelling appeared first in primitive mesenchymal cells and inflammatory cells at the fracture edges and neighboring periosteum at 2-days after fracture, followed by the peaks of periosteal primitive fibroblasts and chondroblasts, which appeared at fracture edges at 3- and 4-days after fracture, respectively. BMP2 was weakly positive in primitive mesenchymal cells, osteoblasts and chondroblasts. At 3-days post-fracture, periosteal osteoblasts produced osteoid tissue and callus with marrow spaces lined by osteoblasts and osteoclasts, and all primitive mesenchymal cells and osteoblasts were positive for TGF-b 1,-2,-3, and TGF-b R1,-R2. They were also positive for vascular growth factors bFGF, FGFR and PDGF, but negative for VEGF, and the peak of PCNA labelling of vascular endothelial cells in the marrow space was delayed to 4-days after fracture. Chondroblasts at fracture edges produced hypertrophic chondrocytes at 5-days after fracture and they were positive for TGF-b 1,-2,-3, and TGF-b R1,-R2. Primitive chondroblasts were positive for vascular growth factors VEGF as well as bFGF, FGFR, and the peak of PCNA labelling of vascular endothelial cells in the cartilage was at 5-days after fracture. Hypertrophic chondrocytes were also positive for these growth factors but negative for bFGF and bFGFR. S-100 protein-induced calcification was only positive on chondroblasts and hypertrophic chondrocytes. At 7-days after fracture, bone began to be formed from the cartilage at fracture edges, by a process similar to bone formation in the growth plate. Enchondral ossification established a bridge between both fracture edges and periosteal membranous ossification encompassed the fracture site like a sheath at 14- day after

Hybrid determination of mixed-mode stress intensity factors on discontinuous finite-width plate by finite element and photoelasticity

International Nuclear Information System (INIS)

Baek, Tae Hyun; Chen, Lei; Hong, Dong Pyo

2011-01-01

For isotropic material structure, the stress in the vicinity of crack tip is generally much higher than the stress far away from it. This phenomenon usually leads to stress concentration and fracture of structure. Previous researches and studies show that the stress intensity factor is one of most important parameter for crack growth and propagation. This paper provides a convenient numerical method, which is called hybrid photoelasticity method, to accurately determine the stress field distribution in the vicinity of crack tip and mixed-mode stress intensity factors. The model was simulated by finite element method and isochromatic data along straight lines far away from the crack tip were calculated. By using the isochromatic data obtained from finite element method and a conformal mapping procedure, stress components and photoelastic fringes in the hybrid region were calculated. To easily compare calculated photoelastic fringes with experiment results, the fringe patterns were reconstructed, doubled and sharpened. Good agreement shows that the method presented in this paper is reliable and convenient. This method can then directly be applied to obtain mixed mode stress intensity factors from the experimentally measured isochromatic data along the straight lines

Risk factors for deep surgical site infection following operative treatment of ankle fractures.

Science.gov (United States)

Ovaska, Mikko T; Mäkinen, Tatu J; Madanat, Rami; Huotari, Kaisa; Vahlberg, Tero; Hirvensalo, Eero; Lindahl, Jan

2013-02-20

Surgical site infection is one of the most common complications following ankle fracture surgery. These infections are associated with substantial morbidity and lead to increased resource utilization. Identification of risk factors is crucial for developing strategies to prevent these complications. We performed an age and sex-matched case-control study to identify patient and surgery-related risk factors for deep surgical site infection following operative ankle fracture treatment. We identified 1923 ankle fracture operations performed in 1915 patients from 2006 through 2009. A total of 131 patients with deep infection were identified and compared with an equal number of uninfected control patients. Risk factors for infection were determined with use of conditional logistic regression analysis. The incidence of deep infection was 6.8%. Univariate analysis showed diabetes (odds ratio [OR] = 2.2, 95% confidence interval [CI] = 1.0, 4.9), alcohol abuse (OR = 3.8, 95% CI = 1.6, 9.4), fracture-dislocation (OR = 2.0, 95% CI = 1.2, 3.5), and soft-tissue injury (a Tscherne grade of ≥1) (OR = 2.6, 95% CI = 1.3, 5.3) to be significant patient-related risk factors for infection. Surgery-related risk factors were suboptimal timing of prophylactic antibiotics (OR = 1.9, 95% CI = 1.0, 3.4), difficulties encountered during surgery, (OR = 2.1, 95% CI = 1.1, 4.0), wound complications (OR = 4.8, 95% CI = 1.6, 14.0), and fracture malreduction (OR = 3.4, 95% CI = 1.3, 9.2). Independent risk factors for infection identified by multivariable analyses were tobacco use (OR = 3.7, 95% CI = 1.6, 8.5) and a duration of surgery of more than ninety minutes (OR = 2.5, 95% CI = 1.1, 5.7). Cast application in the operating room was independently associated with a decreased infection rate (OR = 0.4, 95% CI = 0.2, 0.8). We identified several modifiable risk factors for deep surgical site infection following operative treatment of ankle fractures.

Complications of Open Tibial Fracture Management: Risk Factors and Treatment

OpenAIRE

Lua, JYC; Tan, VH; Sivasubramanian, H; Kwek, EBK

2017-01-01

Open tibial fractures result in high rates of complications. This study aims to elucidate the risk factors causing these complications, and suggest antimicrobial regimens based on the organisms grown in post-operative infections. Over a period of five years, 173 patients had sustained open tibial fractures and undergone operative treatment at a single institution. All surgical data was gathered retrospectively through online medical records. Thirty-one patients (17.9%) had sustained post-oper...

Interfacial fracture of the fibre-metal laminates based on fibre reinforced thermoplastics

International Nuclear Information System (INIS)

Abdullah, M.R.; Prawoto, Y.; Cantwell, W.J.

2015-01-01

As the adhesion quality plays an important role in determining the mechanical performance and environmental stability of most types of fibre-metal laminates (FMLs), investigating the interfacial fracture properties becomes one of the key factors for the improvement. Adhesion of a self-reinforced polypropylene (SRPP) and glass fibre reinforced polypropylene (GFPP) based FML is evaluated experimentally. Single Cantilever Beam (SCB) tests were performed to access interfacial fracture energy (G c ) of the bi-material laminates and their associated interlayer materials. Simulations mimicking the experiments were also performed. The energy needed to fracture was obtained experimentally and also via stress intensity factor from the simulations. The test results show that good adhesion between the aluminium and fibre reinforced thermoplastics can be achieved using a sulphuric acid anodising surface pre-treatment. Further examination has shown that the edges of the test samples highlighted the presence of significant fibre bridging in the SRPP and plastics deformation in the GFPP. - Highlights: • Adhesion of a self-reinforced polypropylene and glass fibre reinforced polypropylene is evaluated. • Single Cantilever Beam tests were performed to access interfacial fracture energy. • The energy needed to fracture was obtained experimentally and also via stress intensity factor from the simulations. • The test results show that best adhesion is achieved using a sulphuric acid anodizing surface pre-treatment

Pubic insufficiency fracture: MRI findings

International Nuclear Information System (INIS)

Min, Tae Kyu; Lee, Yeon Soo; Park, Jeong Mi; Kim, Jee Young; Chung, Hong Jun; Lee, Eun Hee; Lee, Eun Ja; Kang, So Won; Han Tae Il

2000-01-01

To evaluate the characteristic MRI findings of pubic insufficiency fracture. In nine cases of pubic insufficiency fracture, the findings of plain radiography (n=9), MRI (n=9), and bone scintigraphy (n=8) were reviewed. We retrospectively analyzed, with regard to fracture site, the destructive pattern revealed by plain radiography, and uptake by other pelvic bones, as demonstrated by RI bone scanning. The MR findings evaluated were the fracture gap and its signal intensity, the site and signal intensity of the soft tissue mass, and other pelvic bone fractures. Plain radiography revealed osteolysis and sclerosis of pubic bone in eight of nine cases (89%), and parasymphyseal fractures in seven (78%). RI indicated uptake by the sacrum in six cases (66%), and by the ilium in three (33%). MR findings of fracture gap (seven cases, 78%) were hypo to isointensity on T1WI, hyper intensity on T2WI and the absence of contrast enhancement. Soft tissue masses were found in seven cases (78%); in four of these the location was parasymphyseal, and in three, surrounding muscle was involved. Hypo to isointensity was revealed by T1WI, hyperintensity by T2WI, and there was peripheral enhancement. Other associated pelvic bone fractures involved the sacrum in seven cases and the ilium in four. The characteristic MR findings of pubic insufficiency fracture were parasymphyseal location, fracture gap, peripherally enhanced soft tissue mass formation, and fractures of other pelvic bones, namely the sacrum and ilium

Analytical, numerical and experimental investigations of transverse fracture propagation from horizontal wells

Energy Technology Data Exchange (ETDEWEB)

Rahman, M.M.; Hossain, M.M.; Crosby, D.G.; Rahman, M.K.; Rahman, S.S. [School of Petroleum Engineering, The University of New South Wales, 2052 Sydney (Australia)

2002-08-01

This paper presents results of a comprehensive study involving analytical, numerical and experimental investigations into transverse fracture propagation from horizontal wells. The propagation of transverse hydraulic fractures from horizontal wells is simulated and investigated in the laboratory using carefully designed experimental setups. Closed-form analytical theories for Mode I (opening) stress intensity factors for idealized fracture geometries are reviewed, and a boundary element-based model is used herein to investigate non-planar propagation of fractures. Using the mixed mode fracture propagation criterion of the model, a reasonable agreement is found with respect to fracture geometry, net fracture pressures and fracture propagation paths between the modeled fractures and the laboratory tested fractures. These results suggest that the propagation of multiple fractures requires higher net pressures than a single fracture, the underlying reason of which is theoretically justified on the basis of local stress distribution.

Cardiovascular Risk Factor Analysis in Patients with a Recent Clinical Fracture at the Fracture Liaison Service

Directory of Open Access Journals (Sweden)

Caroline E. Wyers

2014-01-01

Full Text Available Patients with a low bone mineral density have an increased risk of cardiovascular diseases (CVD and venous thromboembolic events (VTE. The aim of our retrospective chart review was to investigate the prevalence of CVD, VTE, hypertension (HT, and diabetes mellitus type 2 (DM2 in patients with a recent clinical fracture visiting the Fracture Liaison Service (FLS. Out of 3057 patients aged 50–90 years, 1359 consecutive patients, who agreed and were able to visit the FLS for fracture risk evaluation, were included (71.7% women; mean age 65.2 yrs. Based on medical history, 29.9% had a history of CVD (13.7%, VTE (1.7%, HT (14.9%, and DM2 (7.1% or a combination. Their prevalence increased with age (21% in patients aged 50–59 years to 48% in patients aged >80 years and was higher in men than in women (36% versus 27%, but independent of bone mineral density and fracture type. Careful evaluation of medical history with respect to these risk factors should be performed in patients with a recent clinical fracture before starting treatment with medications that increase the risk of VTE or cardiovascular events, such as raloxifene, strontium ranelate, or NSAIDs.

Hip fractures. Epidemiology, risk factors, falls, energy absorption, hip protectors, and prevention

DEFF Research Database (Denmark)

Lauritzen, J B

1997-01-01

have a high risk of hip fracture (annual rate of 5-6%), and the incidence of falls is about 1,500 falls/1,000 persons/year. Most hip fractures are a result of a direct trauma against the hip. The incidence of falls on the hip among nursing home residents is about 290 falls/1,000 persons/year and about......%, corresponding to 9 out of 247 residents saved from sustaining a hip fracture. The review points to the essentials of the development of hip fracture, which constitutes; risk of fall, type of fall, type of impact, energy absorption, and lastly bone strength, which is the ultimate and last permissive factor......The present review summarizes the pathogenic mechanisms leading to hip fracture based on epidemiological, experimental, and controlled studies. The estimated lifetime risk of hip fracture is about 14% in postmenopausal women and 6% in men. The incidence of hip fractures increases exponentially...

Risk factors for fragility fracture in Seremban district, Malaysia: a comparison of patients with fragility fracture in the orthopedic ward versus those in the outpatient department.

Science.gov (United States)

Keng Yin Loh; King Hock Shong; Soo Nie Lan; Lo, Wan-Yi; Shu Yuen Woon

2008-01-01

Osteoporosis is a silent disease and becomes clinically significant in the presence of fragility fracture. Identifying risk factors that are associated with osteoporosis in the community is important in reducing the incidence of fragility fracture. The aim of this study is to identify risk factors associated with fragility fracture in the Seremban District of Malaysia. This is a population comparison study between orthopedic ward patients and outpatients attending a community health clinic for 6 months. Epidemiological data and the possible risk factors for osteoporosis were collected by direct interview. This study demonstrates that advancing age, low body weight, smoking, lack of regular exercise, low consumption of calcium containing foods, and using bone depleting drugs (steroids, thyroid hormone, and frusemides) are major risk factors for fragility fracture. Most of these risk factors are modifiable through effective lifestyle intervention.

Risk factors for equine fractures in Thoroughbred flat racing in North America.

Science.gov (United States)

Georgopoulos, Stamatis Panagiotis; Parkin, Tim D H

2017-04-01

The aim of this paper is to identify risk factors associated with equine fractures in flat horse racing of Thoroughbreds in North America. Equine fractures were defined as any fracture sustained by a horse during a race. This was a cohort study that made use of all starts from the racecourses reporting injuries. The analysis was based on 2,201,152 racing starts that represent 91% of all official racing starts in the USA and Canada from 1st January 2009-31st December 2014. Approximately 3,990,000 workout starts made by the 171,523 Thoroughbreds that raced during that period were also included in the analysis. During this period the incidence of equine fractures was 2 per 1000 starts. The final multivariable logistic regression models identified risk factors significantly associated (pfracture. For example, horses were found to have a 32% higher chance of sustaining a fracture when racing on a dirt surface compared to a synthetic surface; a 35% higher chance if they had sustained a previous injury during racing and a 47% higher chance was also found for stallions compared to mares and geldings. Furthermore, logistic regression models based on data available only from the period 2009-2013 were used to predict the probability of a Thoroughbred sustaining a fracture for 2014. The 5% of starts that had the highest score in our predictive models for 2014 were found to have 2.4 times (95% CI: 1.9-2.9) higher fracture prevalence than the mean fracture prevalence of 2014. The results of this study can be used to identify horses at higher risk on entering a race and could help inform the design and implementation of preventive measures aimed at minimising the number of Thoroughbreds sustaining fractures during racing in North America. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of the factors influencing the frequency ofpathological fractures in postmenopausal women with osteoporosis

Directory of Open Access Journals (Sweden)

Karadžov-Nikolić A.

2015-01-01

Full Text Available Introduction: Osteoporosis is a disease characterized by bone strength disorder and weakness of the entire skeleton causing the predisposition to fractures to grow. Identification of factors which may influence pathological fractures in postmenopausal women and determining which of the identified factors have the largest influence on the development of osteoporotic fractures. A retrospective study has included 400 postmenopausal women with newly diagnosed osteoporosis examined at the Institute of Rheumatology in Belgrade. We have examined demographic data and the following fracture risk factors: physical activity, menarche, menopause, fractures after the age of forty, osteoporotic fractures in the family, comorbidity: inflammatory rheumatic diseases, intestine diseases, chronic kidney insufficiency and endocrinopathy (hyperthyroidism and diabetes and taking glucocorticoid therapy. The value of bone density has been measured using DXA method in the spine and hip, and the body mass index has been calculated based on the body height and weight. Logistic regression has been used as the method for analyzing the relation between binary results and potential predictors. Statistical hypotheses have been tested at the statistical significance level of 0.05. In the model of multivariate logistic regression, the significant predictors of osteoporotic fractures are as follows: older age (B = 0.13; p = 0.001, higher BMI values (B = 0.094; p = 0.022 and lower BMD values (hip (B = -3.060; p = 0.023. Elderly overweight women with lower BMD values in the hip are more susceptible to fractures due to osteoporosis; therefore this subgroup of postmenopausal women is important for the application of the measures of primary and secondary prevention of osteoporotic fractures.

Screening for postoperative delirium in patients with acute hip fracture: Assessment of predictive factors.

Science.gov (United States)

Koskderelioglu, Asli; Onder, Ozlem; Gucuyener, Melike; Altay, Taskin; Kayali, Cemil; Gedizlioglu, Muhtesem

2017-06-01

The aim of the present study was to estimate the incidence and risk factors of delirium during the early postoperative period after hip fracture surgery. Furthermore, we investigated the accuracy of the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) for detection and assessment of delirium in orthopedic patients. We consecutively recruited patients aged 65 years or older undergoing hip fracture surgery. The presence of delirium was determined daily by two of the authors according to the CAM-ICU criteria. A further evaluation was made with the reference standard Diagnostic and Statistical Manual of Mental Disorders Fourth Edition criteria for delirium. Their cognitive function was evaluated with the Mini-Mental State Examination, and possible depressive mood with the Beck Depression Inventory. Baseline characteristics, as well as the American Society of Anesthesiologists classification and clinical outcomes, were analyzed for a correlation with accompanying delirium. Among 109 patients, 20 (18.3%) were diagnosed with delirium. The concurrent validity of CAM-ICU was good (kappa = 0.84). Specificity was 98.9%, and sensitivity was 80%. Multivariate regression analysis showed that Mini-Mental State Examination (P = 0.001; odds ratio 0.75, 95% confidence interval 0.65-0.86) and Beck Depression Inventory scores (P = 0.001; odds ratio 1.13, 95% confidence interval 1.05-1.22) correlated with the occurrence of delirium. The present results show that CAM-ICU is highly sensitive and specific to identify delirium in hip fracture patients in the postoperative period. Among all of the risk factors, cognitive impairment and depressive mood were strongly associated with postoperative delirium. We suggest that a preoperative assessment of cognition and depression might be useful for identifying patients with a higher risk of postoperative delirium. Geriatr Gerontol Int 2017; 17: 919-924. © 2016 Japan Geriatrics Society.

Surgical Site Infection Following Fixation of Acetabular Fractures.

Science.gov (United States)

Iqbal, Faizan; Younus, Sajid; Asmatullah; Zia, Osama Bin; Khan, Naveed

2017-09-01

Acetabular fractures are mainly caused by high energy trauma. Surgical fixation of these fractures requires extensive surgical exposure which increases the length of operation and blood loss as well. This may increase the risk of surgical site infection. Our aim is to evaluate the prevalence of surgical site infections and the risk factors associated with it so as to minimize its chances. A total of 261 patients who underwent acetabular fracture surgery were retrospectively reviewed. Patients were divided into 2 groups, with or without surgical site infection. Factors examined include patients' gender, age, body mass index (BMI), time between injury and surgery, operative time, estimated blood loss, number of packed red blood cell transfused, length of total intensive care unit (ICU) stay, fracture type, surgical approach, smoking status, patients' comorbids and associated injuries. Fourteen patients (5.4%) developed surgical site infection. Out of 14 infections, 4 were superficial and 10 were deep. The factors that were found to be associated with surgical site infection following acetabular fracture fixation were prolonged operation time, increased BMI, prolonged ICU stay, larger amount of packed red blood cell transfused and associated genitourinary and abdominal trauma. In our study, we conclude that measures should be undertaken to attenuate the chances of surgical site infection in this major surgery by considering the risk factors significantly associated with it.

Influence of scale-dependent fracture intensity on block size distribution and rock slope failure mechanisms in a DFN framework

Science.gov (United States)

Agliardi, Federico; Galletti, Laura; Riva, Federico; Zanchi, Andrea; Crosta, Giovanni B.

2017-04-01

An accurate characterization of the geometry and intensity of discontinuities in a rock mass is key to assess block size distribution and degree of freedom. These are the main controls on the magnitude and mechanisms of rock slope instabilities (structurally-controlled, step-path or mass failures) and rock mass strength and deformability. Nevertheless, the use of over-simplified discontinuity characterization approaches, unable to capture the stochastic nature of discontinuity features, often hampers a correct identification of dominant rock mass behaviour. Discrete Fracture Network (DFN) modelling tools have provided new opportunities to overcome these caveats. Nevertheless, their ability to provide a representative picture of reality strongly depends on the quality and scale of field data collection. Here we used DFN modelling with FracmanTM to investigate the influence of fracture intensity, characterized on different scales and with different techniques, on the geometry and size distribution of generated blocks, in a rock slope stability perspective. We focused on a test site near Lecco (Southern Alps, Italy), where 600 m high cliffs in thickly-bedded limestones folded at the slope scale impend on the Lake Como. We characterized the 3D slope geometry by Structure-from-Motion photogrammetry (range: 150-1500m; point cloud density > 50 pts/m2). Since the nature and attributes of discontinuities are controlled by brittle failure processes associated to large-scale folding, we performed a field characterization of meso-structural features (faults and related kinematics, vein and joint associations) in different fold domains. We characterized the discontinuity populations identified by structural geology on different spatial scales ranging from outcrops (field surveys and photo-mapping) to large slope sectors (point cloud and photo-mapping). For each sampling domain, we characterized discontinuity orientation statistics and performed fracture mapping and circular

Preoperative factors associated with red blood cell transfusion in hip fracture patients

DEFF Research Database (Denmark)

Madsen, Christian Medom; Jørgensen, Henrik Løvendahl; Norgaard, Astrid

2014-01-01

Red blood cell (RBC) transfusion is a frequently used treatment in patients admitted with a fractured hip, but the use remains an area of much debate. The aim of this study was to determine preoperative factors associated with the risk of receiving a red blood cell transfusion in hip fracture...

Effect of Random Natural Fractures on Hydraulic Fracture Propagation Geometry in Fractured Carbonate Rocks

Science.gov (United States)

Liu, Zhiyuan; Wang, Shijie; Zhao, Haiyang; Wang, Lei; Li, Wei; Geng, Yudi; Tao, Shan; Zhang, Guangqing; Chen, Mian

2018-02-01

Natural fractures have a significant influence on the propagation geometry of hydraulic fractures in fractured reservoirs. True triaxial volumetric fracturing experiments, in which random natural fractures are created by placing cement blocks of different dimensions in a cuboid mold and filling the mold with additional cement to create the final test specimen, were used to study the factors that influence the hydraulic fracture propagation geometry. These factors include the presence of natural fractures around the wellbore, the dimension and volumetric density of random natural fractures and the horizontal differential stress. The results show that volumetric fractures preferentially formed when natural fractures occurred around the wellbore, the natural fractures are medium to long and have a volumetric density of 6-9%, and the stress difference is less than 11 MPa. The volumetric fracture geometries are mainly major multi-branch fractures with fracture networks or major multi-branch fractures (2-4 fractures). The angles between the major fractures and the maximum horizontal in situ stress are 30°-45°, and fracture networks are located at the intersections of major multi-branch fractures. Short natural fractures rarely led to the formation of fracture networks. Thus, the interaction between hydraulic fractures and short natural fractures has little engineering significance. The conclusions are important for field applications and for gaining a deeper understanding of the formation process of volumetric fractures.

Fracture analysis of a transversely isotropic high temperature superconductor strip based on real fundamental solutions

International Nuclear Information System (INIS)

Gao, Zhiwen; Zhou, Youhe

2015-01-01

Highlights: • We studied fracture problem in HTS based on real fundamental solutions. • When the thickness of HTS strip increases the SIF decrease. • A higher applied field leads to a larger stress intensity factor. • The greater the critical current density is, the smaller values of the SIF is. - Abstract: Real fundamental solution for fracture problem of transversely isotropic high temperature superconductor (HTS) strip is obtained. The superconductor E–J constitutive law is characterized by the Bean model where the critical current density is independent of the flux density. Fracture analysis is performed by the methods of singular integral equations which are solved numerically by Gauss–Lobatto–Chybeshev (GSL) collocation method. To guarantee a satisfactory accuracy, the convergence behavior of the kernel function is investigated. Numerical results of fracture parameters are obtained and the effects of the geometric characteristics, applied magnetic field and critical current density on the stress intensity factors (SIF) are discussed

Correlation of fracture parameters during onset of crack in middle tension specimen

Directory of Open Access Journals (Sweden)

M.S. Starvin

2017-07-01

Full Text Available The present study addresses the implementation of finite element analysis and the prediction of fracture parameters in a middle tension (MT specimen that was fabricated using AISI 4140 steel. The correlation of fracture parameters with external loads and crack sizes was investigated. A Finite Element code was developed to simulate the fracture model. The contour integral method was applied in the calculation of stress intensity factor and J-integral in the cracked specimen. The ASTM standard empirical formula was used to calculate the stress intensity factor (SIF and the numerical predictions were validated. A standard laboratory experiment was also carried out using the MT specimen to calculate the crack growth rate in this specific material. The SIF values were almost linear with external load but it was decreasing as the crack size increases. The crack requires minimum load for crack propagation as the crack size increases. Similarly the J-integral was accelerated with increase in crack size.

Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors

International Nuclear Information System (INIS)

Nambu, Atsushi; Marino, Kan; Koshiishi, Tsuyota; Sawada, Eiichi; Araki, Tsutomu; Onishi, Hiroshi; Aoki, Shinichi; Tominaga, Licht; Kuriyama, Kengo; Araya, Masayuki; Saito, Ryoh; Maehata, Yoshiyasu; Komiyama, Takafumi

2013-01-01

As stereotactic body radiotherapy (SBRT) is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated. Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT). The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED) was calculated with a range of α/β ratios (1–10 Gy). Receiver operating characteristics analysis was used to define the most appropriate α/β ratio. Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41), and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy. Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients

Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors

Directory of Open Access Journals (Sweden)

Nambu Atsushi

2013-02-01

Full Text Available Abstract Background As stereotactic body radiotherapy (SBRT is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated. Methods Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT. The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED was calculated with a range of α/β ratios (1–10 Gy. Receiver operating characteristics analysis was used to define the most appropriate α/β ratio. Results Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41, and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy. Conclusions Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients.

Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors

Science.gov (United States)

2013-01-01

Background As stereotactic body radiotherapy (SBRT) is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated. Methods Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT). The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED) was calculated with a range of α/β ratios (1–10 Gy). Receiver operating characteristics analysis was used to define the most appropriate α/β ratio. Results Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41), and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy. Conclusions Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients. PMID:23391264

Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors.

Science.gov (United States)

Nambu, Atsushi; Onishi, Hiroshi; Aoki, Shinichi; Tominaga, Licht; Kuriyama, Kengo; Araya, Masayuki; Saito, Ryoh; Maehata, Yoshiyasu; Komiyama, Takafumi; Marino, Kan; Koshiishi, Tsuyota; Sawada, Eiichi; Araki, Tsutomu

2013-02-07

As stereotactic body radiotherapy (SBRT) is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated. Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT). The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED) was calculated with a range of α/β ratios (1-10 Gy). Receiver operating characteristics analysis was used to define the most appropriate α/β ratio. Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41), and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy. Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients.

Effect of TiC addition on fracture toughness of Al6061 alloy

Science.gov (United States)

Raviraj, M. S.; Sharanprabhu, C. M.; Mohankumar, G. C.

2018-04-01

Al 6061 matrix was reinforced with different proportions of TiC particles such as 3wt%, 5wt% and 7wt% and the effect on fracture toughness was studied. Al-TiC metal matrix composites were produced by stir casting method to ensure uniform distribution of the TiC particulates in the Al matrix. LEFM (Linear Elastic Fracture Mechanics) has been used to characterize the fracture toughness using various specimen geometries. The compact tension (CT) specimens with straight through notch were machined as per ASTM E399 specifications. All the specimens were machined to have constant a/W=0.5 and B/W was varied from 0.2 to 0.7. A sharp crack initiation was done at the end of notch by fatigue loading using servo-hydraulic controlled testing machine. Load v/s crack mouth opening displacement (CMOD) data was plotted and stress intensity factor, KQ determined. Critical stress intensity factor KIC was obtained by plotting KQ v/s thickness of specimen data. The fracture toughness of the composites varied between 16-19 MPa√m as compared to 23MPa√m for base alloy Al6061. Composites with 3wt% and 7wt% TiC showed better fracture toughness than 5wt% TiC reinforced Al metal matrix composites.

Influence of fall related factors and bone strength on fracture risk in the frail elderly.

Science.gov (United States)

Sambrook, P N; Cameron, I D; Chen, J S; Cumming, R G; Lord, S R; March, L M; Schwarz, J; Seibel, M J; Simpson, J M

2007-05-01

When subjects are selected on the basis of fall risk alone, therapies for osteoporosis have not been effective. In a prospective study of elderly subjects at high risk of falls, we investigated the influence of bone strength and fall risk on fracture. At baseline we assessed calcaneal bone ultrasound attenuation (BUA) as well as quantitative measures of fall risk in 2005 subjects in residential care. Incident falls and fractures were recorded (median follow-up 705 days). A total of 6646 fall events and 375 low trauma fracture events occurred. The fall rate was 214 per 100 person years and the fracture rate 12.1 per 100 person years. 82% of the fractures could be attributed to falls. Although fracture rates increased with decreasing BUA (incidence rate ratio 1.94 for lowest vs. highest BUA tertile, pfalls also affected fracture incidence. Subjects who fell frequently (>3.15 falls/per person year) were 3.35 times more likely to suffer a fracture than those who did not fall. Some fall risk factors such as balance were associated with the lowest fracture risk lowest in the worst performing group. Multivariate analysis revealed higher fall rate, history of previous fracture, lower BUA, lower body weight, cognitive impairment and better balance as significant independent risk factors for fracture. In the frail elderly, both skeletal fragility and fall risk including the frequency of exposure to falls are important determinants of fracture risk.

Couple stresses and the fracture of rock.

Science.gov (United States)

Atkinson, Colin; Coman, Ciprian D; Aldazabal, Javier

2015-03-28

An assessment is made here of the role played by the micropolar continuum theory on the cracked Brazilian disc test used for determining rock fracture toughness. By analytically solving the corresponding mixed boundary-value problems and employing singular-perturbation arguments, we provide closed-form expressions for the energy release rate and the corresponding stress-intensity factors for both mode I and mode II loading. These theoretical results are augmented by a set of fracture toughness experiments on both sandstone and marble rocks. It is further shown that the morphology of the fracturing process in our centrally pre-cracked circular samples correlates very well with discrete element simulations. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Factors influencing period from surgery to discharge in patients with femoral trochanteric fractures

Science.gov (United States)

Shinoda, Soichiro; Mutsuzaki, Hirotaka; Watanabe, Arata; Morita, Hidetaka; Kamioka, Yumiko

2017-01-01

[Purpose] The purpose of this study was to investigate factors influencing the period from surgery to discharge in patients with femoral trochanteric fractures. [Subjects and Methods] Sixty patients with femoral trochanteric fractures were investigated retrospectively. Based on the mean period from surgery to discharge (85.6 ± 26.6 days), the patients were divided into two groups: an under-85-day group (range, 29–78 days) and an over-85-day group (87–128 days). Age, gender, fracture type, presence of lesser trochanteric displacement, discharge destination, and walking ability were investigated. The relationship between these factors and the period from surgery to discharge was analyzed with logistic regression analysis. [Results] Age and lesser trochanteric displacement were significantly higher in the over-85-day group, and walking ability before fracture and at discharge were significantly lower in the over-85-day group. Logistic regression analysis showed that lesser trochanteric displacement and age were predictors of the length from surgery to discharge. Lesser trochanteric displacement were observed in 87.5% of these. Immediate displacement after surgery occurred in 57.8% of lesser trochanteric fractures, while 26.3% displaced 1 to 3 weeks after surgery. [Conclusion] This study revealed that lesser trochanteric displacement, higher age, and lower walking ability before fracture and at discharge were associated with longer hospitalizations in patients with femoral trochanteric fractures. Lesser trochanteric displacement were observed in 87.5% of lesser trochanteric fractures. These displacements occurred within 3 weeks after surgery in 84.1% of cases. PMID:29200639

Malnutrition and chronic inflammation as risk factors for sarcopenia in elderly patients with hip fracture.

Science.gov (United States)

Yoo, Jun-Il; Ha, Yong-Chan; Choi, Hana; Kim, Kyu-Hwang; Lee, Young-Kyun; Koo, Kyung-Hoi; Park, Ki-Soo

2018-01-01

To evaluate malnutrition and chronic inflammation as risk factors for sarcopenia in elderly patients with hip fractures, as defined by the criteria of the Asian Working Group on Sarcopenia (AWGS). A total of 327 elderly patients with hip fractures were enrolled in this retrospective observational study. The main outcome measure was the nutritional status and nutritional risk factors for sarcopenia in elderly patients. Diagnosis of sarcopenia was made according to the guidelines of the AWGS. Whole body densitometry analysis was used to measure skeletal muscle mass, and muscle strength was evaluated by handgrip testing. Multivariable regression analysis was utilized to analyze the nutritional risk factors for sarcopenia in patients with hip fractures. Of 327 patients with hip fractures (78 men and 249 women), the prevalence of sarcopenia was 60.3% and 30.1% in men and women, respectively. The rates of three indicators of malnutrition in men and women (low BMI, hypoalbuminemia, and hypoproteinemia) in sarcopenia patients with hip fractures were 23.4%, 31.9%, and 53.2% and 21.3%, 21.3%, and 37.3%, respectively. The prevalence of markers of chronic inflammation (increased CRP and ESR) in men and women with sarcopenia and hip fractures were 74.9% and 52.2%, and 49.3% and 85.1%, respectively. After adjusting for covariates, low BMI and hypoproteinemia in women were associated with a 2.9- and 2.1-fold greater risk of sarcopenia than non-sarcopenia, respectively. The present study revealed a strong relationship between sarcopenia and malnutrition and chronic inflammatory factors in elderly patients with hip fractures.

Risk factors for equine fractures in Thoroughbred flat racing in North America

OpenAIRE

Georgopoulos, Stamatis Panagiotis; Parkin, Tim D.H.

2017-01-01

The aim of this paper is to identify risk factors associated with equine fractures in flat horse racing of Thoroughbreds in North America. Equine fractures were defined as any fracture sustained by a horse during a race. This was a cohort study that made use of all starts from the racecourses reporting injuries. The analysis was based on 2,201,152 racing starts that represent 91% of all official racing starts in the USA and Canada from 1 st January 2009–31 st December 2014. Approximately 3,99...

Failure and fracture of thin film materials for MEMS

Science.gov (United States)

Jonnalagadda, Krishna Nagasai

Design and reliable operation of Microelectromechanical systems (MEMS) depend on the material parameters that influence the failure and fracture properties of brittle and metallic thin films. Failure in brittle materials is quantified by the onset of catastrophic fracture, while in metals, the onset of inelastic deformation is considered as failure as it increases the material compliance. This dissertation research developed new experimental methods to address three aspects on the failure response of these two categories of materials: (a) the role of microstructure and intrinsic stress gradients in the opening mode fracture of mathematically sharp pre-cracks in amorphous and polycrystalline brittle thin films, (b) the critical conditions for mixed mode I/II pre-cracks and their comparison with linear elastic fracture mechanics (LEFM) criteria for crack initiation in homogeneous materials, and (c) the strain rate sensitivity of textured nanocrystalline Au and Pt films with grain sizes of 38 nm and 25 nm respectively. One of the technical objectives of this research was to develop experimental methods and tools that could become standards in MEMS and thin film experimental mechanics. In this regard, a new method was introduced to conduct mode I and mixed mode I/II fracture studies with microscale thin film specimens containing sharp edge pre-cracks. The mode I experiments permitted the direct application of LEFM handbook solutions. On the other hand, the newly introduced mixed mode I/II experiments in thin films were conducted by establishing a new protocol that employs non-standard oblique edge pre-cracks and a numerical analysis based on the J-integral to calculate the stress intensity factors. Similarly, a new experimental protocol has been implemented to carry out experiments with metallic thin films at strain rates that vary by more than six orders of magnitude. The results of mode I fracture experiments concluded that grain inhomogeneity in polycrystalline

Fatigue fracture analysis in medium carbon structural steel and austenitic stainless steel by X-ray fractography

International Nuclear Information System (INIS)

Rao, N.N.; Azmi bin Rahmat

1994-01-01

Apart from the reidual stresses present in the bulk material, a growing fatigue crack may develop its own stress field ahead of the crack tip which in turn could influence the crack propagation behaviour. A fracture surface analysis through measurement of the residual stress of a failed component may provide some additional useful information to that obtained through conventional metallurgical and fracture mechanics investigations. This method of fracture surface analysis using x-ray diffraction technique is known as X -ray Fractography . Residual stress (ρ sub γ) and the full width at half maximum (FWHM) of the x-ray diffraction profile of any reflection are determined at different crack lengths on the fracture surface. These are then corelated to the fracture toughness parameters such as fracture toughness K sub I sub C, the maximum stress intensity factor K sub max and the stress intensity factor range δK. The present investigation aims at detailed x-ray analysis of the fatigue fractured surfaces of the compact tension specimens prepared from ferritic and austenitic stainless steels. The ferritic steel has been subjected to various heat treatments to obtain different microstructures and mechanical properties. The overall observations are analyzed through fatigue (cumulative) damage and material science concepts

Fear of Falling in Patients With Hip Fractures: Prevalence and Related Psychological Factors

NARCIS (Netherlands)

Visschedijk, J.; Van Balen, R.; Hertogh, C.M.P.M.; Achterberg, W.

2013-01-01

Objective: To determine the prevalence of fear of falling (FoF) in patients after a hip fracture, to investigate the relation with time after fracture, and to assess associations between FoF and other psychological factors. Design: Cross-sectional study performed between September 2010 and March

Crack tip fields and mixed mode fracture behaviour of progressively drawn pearlitic steel

Directory of Open Access Journals (Sweden)

J. Toribio

2015-07-01

Full Text Available This paper deals with the influence of the cold drawing process on the fracture behaviour of pearlitic steels. To this end, fracture tests under axial loading were performed on steel wires with different drawing degree (from a hot rolled bar to a commercial prestressing steel wire, transversely pre-cracked by fatigue, analyzing in detail the changes in fracture micromechanisms. The deflection angles of the fracture path were measured by longitudinal metallographic sections and the characteristic parameters of the loaddisplacement plot were related to different fracture events. Results allowed a calculation of critical stress intensity factors for different fracture angles and drawing degrees, thus evaluating the strength anisotropy and obtaining a sort of directional toughness.

Risk factors for cervical and trochanteric hip fractures in elderly women: a population-based 10-year follow-up study.

Science.gov (United States)

Jokinen, Heikki; Pulkkinen, Pasi; Korpelainen, Juha; Heikkinen, Jorma; Keinänen-Kiukaanniemi, Sirkka; Jämsä, Timo; Korpelainen, Raija

2010-07-01

We evaluated the contribution of lifestyle-related factors, calcaneal ultrasound, and radial bone mineral density (BMD) to cervical and trochanteric hip fractures in elderly women in a 10-year population-based cohort study. The study population consisted of 1,681 women (age range 70-73 years). Seventy-two percent (n = 1,222) of them participated in the baseline measurements. Calcaneal ultrasound was assessed with a quantitative ultrasound device. BMD measurements were performed at the distal and ultradistal radius by dual-energy X-ray absorptiometry. Forward stepwise logistic regression analysis was used to find the most predictive variables for hip fracture risk. During the follow-up, 53 of the women had hip fractures, including 32 cervical and 21 trochanteric ones. The fractured women were taller and thinner and had lower calcaneal ultrasound values than those without fractures. High body mass index (BMI) was a protective factor against any hip fractures, while low functional mobility was a risk factor of hip fractures. Specifically, high BMI protected against cervical hip fractures, while low physical activity was a significant predictor of these fractures. Similarly, high BMI protected against trochanteric fractures, whereas low functional mobility and high coffee consumption were significant predictors of trochanteric fractures. Cervical and trochanteric hip fractures seem to have different risk factors. Therefore, fracture type should be taken into account in clinical fracture risk assessment and preventative efforts, including patient counseling. However, the study is not conclusive due to the limited number of observed fractures during follow-up, and the results have to be confirmed in future studies.

Standard test method for determining a threshold stress intensity factor for environment-assisted cracking of metallic materials

CERN Document Server

American Society for Testing and Materials. Philadelphia

2003-01-01

1.1 This test method covers the determination of the environment-assisted cracking threshold stress intensity factor parameters, KIEAC and KEAC, for metallic materials from constant-force testing of fatigue precracked beam or compact fracture specimens and from constant-displacement testing of fatigue precracked bolt-load compact fracture specimens. 1.2 This test method is applicable to environment-assisted cracking in aqueous or other aggressive environments. 1.3 Materials that can be tested by this test method are not limited by thickness or by strength as long as specimens are of sufficient thickness and planar size to meet the size requirements of this test method. 1.4 A range of specimen sizes with proportional planar dimensions is provided, but size may be variable and adjusted for yield strength and applied force. Specimen thickness is a variable independent of planar size. 1.5 Specimen configurations other than those contained in this test method may be used, provided that well-established stress ...

Effect of loading rate on dynamic fracture of reaction bonded silicon nitride

Science.gov (United States)

Liaw, B. M.; Kobayashi, A. S.; Emery, A. F.

1986-01-01

Wedge-loaded, modified tapered double cantilever beam (WL-MTDCB) specimens under impact loading were used to determine the room temperature dynamic fracture response of reaction bonded silicon nitride (RBSN). The crack extension history, with the exception of the terminal phase, was similar to that obtained under static loading. Like its static counterpart, a distinct crack acceleration phase, which was not observed in dynamic fracture of steel and brittle polymers, was noted. Unlike its static counterpart, the crack continued to propagate at nearly its terminal velocity under a low dynamic stress intensity factor during the terminal phase of crack propagation. These and previously obtained results for glass and RBSN show that dynamic crack arrest under a positive dynamic stress intensity factor is unlikely in static and impact loaded structural ceramics.

Quantifying Fracture Heterogeneity in Different Domains of Folded Carbonate Rocks to Improve Fractured Reservoir Analog Fluid Flow Models

NARCIS (Netherlands)

Bisdom, K.; Bertotti, G.; Gauthier, B.D.M.; Hardebol, N.J.

2013-01-01

Fluid flow in carbonate reservoirs is largely controlled by multiscale fracture networks. Significant variations of fracture network porosity and permeability are caused by the 3D heterogeneity of the fracture network characteristics, such as intensity, orientation and size. Characterizing fracture

Factors influencing period from surgery to discharge in patients with femoral trochanteric fractures

OpenAIRE

Shinoda, Soichiro; Mutsuzaki, Hirotaka; Watanabe, Arata; Morita, Hidetaka; Kamioka, Yumiko

2017-01-01

[Purpose] The purpose of this study was to investigate factors influencing the period from surgery to discharge in patients with femoral trochanteric fractures. [Subjects and Methods] Sixty patients with femoral trochanteric fractures were investigated retrospectively. Based on the mean period from surgery to discharge (85.6 ± 26.6 days), the patients were divided into two groups: an under-85-day group (range, 29–78 days) and an over-85-day group (87–128 days). Age, gender, fracture type, pre...

Dynamic fracture initiation in brittle materials under combined mode I/II loading

International Nuclear Information System (INIS)

Nakano, M.; Kishida, K.; Yamauchi, Y.; Sogabe, Y.

1994-01-01

A new test method has been developed to measure the resistance of dynamic fracture initiation in brittle materials under combined mode I/II loadings. The Brazilian disks with center-cracks have been fractured under oblique impact loadings in diametral-compression. The dynamic stress intensity factors of mode I and II are evaluated from the superposition integrals of the step response functions for the cracked disk. The experimental results are presented to elucidate the influence of loading rate on the combined mode fracture toughness for ceramics and glasses. (orig.)

A proposed standard round compact specimen for plane strain fracture toughness testing

Science.gov (United States)

Underwood, J. H.; Newman, J. C., Jr.; Seeley, R. R.

1980-01-01

A round, disk-shaped specimen is proposed as a standard test specimen for addition to ASTM Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399-78A). The specimen is diametrically cracked, and loaded in the same way as the existing standard compact specimen. Tests and analyses were performed to verify that the proposed round compact specimen and associated stress intensity factor K solution are appropriate for a standard plane strain fracture toughness test. The use of the round compact specimen for other fracture tests is described.

Osteoporosis among Fallers without Concomitant Fracture Identified in an Emergency Department: Frequencies and Risk Factors

DEFF Research Database (Denmark)

Glintborg, Bente; Hesse, Ulrik; Houe, Thomas

2011-01-01

aged 50-80 years sustaining a low-energy fall without fracture were identified from an ED (n = 199). Patients answered a questionnaire on risk factors and underwent osteodensitometry. Data was compared to a group of patients routinely referred to osteodensitometry from general practice (n = 201......). Results. Among the 199 included fallers, 41 (21%) had osteoporosis. Among these, 35 (85%) reported either previous fracture or reduced body height (>3¿cm). These two risk factors were more frequent among fallers with osteoporosis compared to fallers with normal bone mineral density or osteopenia (previous...... if the patient has a prior fracture or declined body height. Since fallers generally have higher fracture risk, the ED might serve as an additional entrance to osteodensitometry compared to referral from primary care....

Osteoporotic compression fracture of the thoracolumbar spine and sacral insufficiency fracture: incidence and analysis of the relationship according to the clinical factors

International Nuclear Information System (INIS)

Kong, Jeong Hwa; Park, Ji Sun; Ryu, Kyung Nam

2006-01-01

To evaluate the incidence of sacral insufficiency fracture in osteoporotic patient with compression fracture of the thoracolumbar (T-L) spine on magnetic resonance image (MRI), and to analyze the correlation of variable clinical factors and the incidence of sacral insufficiency fracture. We retrospectively reviewed 160 patients (27 men, 133 women; age range of 50 to 89 years) who underwent spinal MRI and had compression fracture of the T-L spine. Compression fractures due to trauma or tumor were excluded. We evaluated the incidence of sacral insufficiency fracture according to the patients' age, sex, number of compression fractures, and the existence of bone marrow edema pattern of compression fracture. During the same period, we evaluated the incidence of spinal compression fracture in the patients of pelvic insufficiency fracture. Out of the 160 patients who had compression fracture in the T-L spine, 17 (10.6%) had insufficiency fracture of the sacrum. Compression fracture occurred almost 5 times more frequently in women (27:133), but the incidence of sacral insufficiency fracture was 2/27 for men (7.4%) and 15/133 for women (11.3%), with no statistically significant difference (ρ = 0.80). According to age, the ratio of insufficiency fracture to compression fracture was 0% (0/23) in the 50's, 10.6% (7/66) in the 60's, 12.5% (7/56) in the 70's, and 20.0% (3/15) in the 80's. In respect of single and multiple compression fracture, the incidence of sacral insufficiency fracture was 8/65 for men (12.3%) and 9/95 for women (9.5%), showing no significant difference (ρ = 0.37). In the patients with and without compression fracture with bone marrow edema, insufficiency fracture occurred in 5/76 (6.6%) and 12/84 (14.3%), respectively. On the other hand, of the 67 patients who had pelvic insufficiency fracture, 27 (40.3%) also had spinal compression fracture. About 10% of the patients with osteoporotic compression fracture in the T/L spine also had pelvic sacral

Quantitative analysis by X-ray fractography of fatigue fractured surface under variable amplitude loading

International Nuclear Information System (INIS)

Akita, Koichi; Kodama, Shotaro; Misawa, Hiroshi

1994-01-01

X-ray fractography is a method of analysing the causes of accidental fracture of machine components or structures. Almost all of the previous research on this problem has been carried out using constant amplitude fatigue tests. However, the actual loads on components and structures are usually of variable amplitudes. In this study, X-ray fractography was applied to fatigue fractured surfaces produced by variable amplitude loading. Fatigue tests were carried out on Ni-Cr-Mo steel CT specimens under the conditions of repeated, two-step and multiple-step loading. Residual stresses were measured on the fatigue fractured surface by an X-ray diffraction method. The relationships between residual stress and stress intensity factor or crack propagation rate were studied. They were discussed in terms of the quantitative expressions under constant amplitude loading, proposed by the authors in previous papers. The main results obtained were as follows : (1) It was possible to estimate the crack propagation rate of the fatigue fractured surface under variable amplitude loading by using the relationship between residual stress and stress intensity factor under constant amplitude loading. (2) The compressive residual stress components on the fatigue fractured surface correspond with cyclic softening of the material rather than with compressive plastic deformation at the crack tip. (author)

Acoustic emission characterization of fracture toughness for fiber reinforced ceramic matrix composites

International Nuclear Information System (INIS)

Mei, Hui; Sun, Yuyao; Zhang, Lidong; Wang, Hongqin; Cheng, Laifei

2013-01-01

The fracture toughness of a carbon fiber reinforced silicon carbide composite was investigated relating to classical critical stress intensity factor K IC , work of fracture, and acoustic emission energy. The K IC was obtained by the single edge notch beam method and the work of fracture was calculated using the featured area under the load–displacement curves. The K IC , work of fracture, and acoustic emission energy were compared for the composites before and after heat treatment and then analyzed associated with toughening microstructures of fiber pullout. It indicates that the work of fracture and acoustic emission energy can be more suitable to reflect the toughness rather than the traditional K IC , which has certain limitation for the fracture toughness characterization of the crack tolerant fiber ceramic composites.

Physiological role of growth factors and bone morphogenetic proteins in osteogenesis and bone fracture healing: а review

Directory of Open Access Journals (Sweden)

S. Sagalovsky

2015-01-01

Full Text Available The repair of large bone defects remains a major clinical orthopedic challenge. Bone regeneration and fracture healing is a complex physiological mechanisms regulated by a large number of biologically active molecules. Multiple factors regulate this cascade of molecular events, which affects different stages in the osteoblast and chondroblast lineage during such processes as migration, proliferation, chemotaxis, differentiation, inhibition, and extracellular protein synthesis. A recent review has focused on the mechanisms by which growth and differentiation factors regulate the fracture healing process. Rapid progress in skeletal cellular and molecular biology has led to identification of many signaling molecules associated with formation of skeletal tissues, including a large family of growth factors (transforming growth factor-β and bone morphogenetic proteins, fibroblast growth factor, insulin-like growth factor, vascular endothelial growth factor, platelet-derived growth factor, cytokines and interleukins. There is increasing evidence indicating that they are critical regulators of cellular proliferation, differentiation, extracellular matrix biosynthesis and bone mineralization. A clear understanding of cellular and molecular pathways involved in fracture healing is not only critical for improvement of fracture treatments, but it may also enhance further our knowledge of mechanisms involved in skeletal growth and repair, as well as mechanisms of aging. This suggests that, in the future, they may play a major role in the treatment of bone disease and fracture repair.

Statistical model of fractures and deformations zones for Forsmark. Preliminary site description Forsmark area - version 1.2

Energy Technology Data Exchange (ETDEWEB)

La Pointe, Paul R. [Golder Associate Inc., Redmond, WA (United States); Olofsson, Isabelle; Hermanson, Jan [Golder Associates AB, Uppsala (Sweden)

2005-04-01

Compared to version 1.1, a much larger amount of data especially from boreholes is available. Both one-hole interpretation and Boremap indicate the presence of high and low fracture intensity intervals in the rock mass. The depth and width of these intervals varies from borehole to borehole but these constant fracture intensity intervals are contiguous and present quite sharp transitions. There is not a consistent pattern of intervals of high fracture intensity at or near to the surface. In many cases, the intervals of highest fracture intensity are considerably below the surface. While some fractures may have occurred or been reactivated in response to surficial stress relief, surficial stress relief does not appear to be a significant explanatory variable for the observed variations in fracture intensity. Data from the high fracture intensity intervals were extracted and statistical analyses were conducted in order to identify common geological factors. Stereoplots of fracture orientation versus depth for the different fracture intensity intervals were also produced for each borehole. Moreover percussion borehole data were analysed in order to identify the persistence of these intervals throughout the model volume. The main conclusions of these analyses are the following: The fracture intensity is conditioned by the rock domain, but inside a rock domain intervals of high and low fracture intensity are identified. The intervals of high fracture intensity almost always correspond to intervals with distinct fracture orientations (whether a set, most often the NW sub-vertical set, is highly dominant, or some orientation sets are missing). These high fracture intensity intervals are positively correlated to the presence of first and second generation minerals (epidote, calcite). No clear correlation for these fracture intensity intervals has been identified between holes. Based on these results the fracture frequency has been calculated in each rock domain for the

Statistical model of fractures and deformations zones for Forsmark. Preliminary site description Forsmark area - version 1.2

International Nuclear Information System (INIS)

La Pointe, Paul R.; Olofsson, Isabelle; Hermanson, Jan

2005-04-01

Compared to version 1.1, a much larger amount of data especially from boreholes is available. Both one-hole interpretation and Boremap indicate the presence of high and low fracture intensity intervals in the rock mass. The depth and width of these intervals varies from borehole to borehole but these constant fracture intensity intervals are contiguous and present quite sharp transitions. There is not a consistent pattern of intervals of high fracture intensity at or near to the surface. In many cases, the intervals of highest fracture intensity are considerably below the surface. While some fractures may have occurred or been reactivated in response to surficial stress relief, surficial stress relief does not appear to be a significant explanatory variable for the observed variations in fracture intensity. Data from the high fracture intensity intervals were extracted and statistical analyses were conducted in order to identify common geological factors. Stereoplots of fracture orientation versus depth for the different fracture intensity intervals were also produced for each borehole. Moreover percussion borehole data were analysed in order to identify the persistence of these intervals throughout the model volume. The main conclusions of these analyses are the following: The fracture intensity is conditioned by the rock domain, but inside a rock domain intervals of high and low fracture intensity are identified. The intervals of high fracture intensity almost always correspond to intervals with distinct fracture orientations (whether a set, most often the NW sub-vertical set, is highly dominant, or some orientation sets are missing). These high fracture intensity intervals are positively correlated to the presence of first and second generation minerals (epidote, calcite). No clear correlation for these fracture intensity intervals has been identified between holes. Based on these results the fracture frequency has been calculated in each rock domain for the

Complications and their risk factors following hip fracture surgery.

Science.gov (United States)

Poh, Keng Soon; Lingaraj, K

2013-08-01

PURPOSE. To evaluate various postoperative complications and their risk factors in hip fracture patients. METHODS. 207 female and 87 male consecutive patients (mean age, 78.1 years) who underwent surgical (n=242) or conservative (n=52) treatment for closed fractures of the femoral neck (n=157) or peritrochanter (n=137) were prospectively studied. The types of complication and outcome were recorded. The comorbidity status of the patients was categorised based on the American Society of Anesthesiologists (ASA) classification. Complications and their associations with various risk factors and mortality were analysed. RESULTS. For all patients, the mean length of hospitalisation was 14.6 days. For the 242 patients who underwent surgical treatment after a mean of 3.6 days, 56.8% of them had at least one complication. Acute urinary retention (39.3%) and urinary tract infection (24.0%) were most common. Patients with ASA grade III or higher had 2.3 fold higher risk of developing complications than those with lower-grade comorbidity, whereas patients with delayed operation (>48 hours after presentation) had 1.8 fold higher risk of developing complications than those without delayed operation. Four patients died in hospital: 2 from myocardial infarction and 2 from upper gastrointestinal bleeding. CONCLUSION. Complications after hip fracture surgery were common. Advanced age, high ASA status, and delay in surgery were associated with higher complication rates. Operations should be performed on medically fit patients as early as possible.

Risk factors for surgical site infection following operative ankle fracture fixation.

Science.gov (United States)

Kelly, E G; Cashman, J P; Groarke, P J; Morris, S F

2013-09-01

Ankle fracture is a common injury and there is an increasingly greater emphasis on operative fixation. The purpose of the study was to determine the complication rate in this cohort of patients and, in doing so, determine risk factors which predispose to surgical site infection. A prospective cohort study was performed at a tertiary referral trauma center examining risk factors for surgical site infection in operatively treated ankle fractures. Univariate and multivariate analysis was performed. Female gender and advancing age were determined to be the risk factors in univariate analysis. Drain usage and peri-operative pyrexia were found to be significant for infection in multivariate analysis. This study allows surgeons to identify those at increased risk of infection and counsel them appropriately. It also allows for a high level of vigilance with regard to soft tissue handling intra-operatively in this higher risk group.

Fracture mechanics applied to the machining of brittle materials

Energy Technology Data Exchange (ETDEWEB)

Hiatt, G.D.; Strenkowski, J.S.

1988-12-01

Research has begun on incorporating fracture mechanics into a model of the orthogonal cutting of brittle materials. Residual stresses are calculated for the machined material by a combination of Eulerian and Lagrangian finite element models and then used in the calculation of stress intensity factors by the Green`s Function Method.

Numerical methods in dynamic fracture mechanics

International Nuclear Information System (INIS)

Beskos, D.E.

1987-01-01

A review of numerical methods for the solution of dynamic problems of fracture mechanics is presented. Finite difference, finite element and boundary element methods as applied to linear elastic or viscoelastic and non-linear elastoplastic or elastoviscoplastic dynamic fracture mechanics problems are described and critically evaluated. Both cases of stationary cracks and rapidly propagating cracks of simple I, II, III or mixed modes are considered. Harmonically varying with time or general transient dynamic disturbances in the form of external loading or incident waves are taken into account. Determination of the dynamic stress intensity factor for stationary cracks or moving cracks with known velocity history as well as determination of the crack-tip propagation history for given dynamic fracture toughness versus crack velocity relation are described and illustrated by means of certain representative examples. Finally, a brief assessment of the present state of knowledge is made and research needs are identified

Statistical methodology for discrete fracture model - including fracture size, orientation uncertainty together with intensity uncertainty and variability

Energy Technology Data Exchange (ETDEWEB)

Darcel, C. (Itasca Consultants SAS (France)); Davy, P.; Le Goc, R.; Dreuzy, J.R. de; Bour, O. (Geosciences Rennes, UMR 6118 CNRS, Univ. def Rennes, Rennes (France))

2009-11-15

Investigations led for several years at Laxemar and Forsmark reveal the large heterogeneity of geological formations and associated fracturing. This project aims at reinforcing the statistical DFN modeling framework adapted to a site scale. This leads therefore to develop quantitative methods of characterization adapted to the nature of fracturing and data availability. We start with the hypothesis that the maximum likelihood DFN model is a power-law model with a density term depending on orientations. This is supported both by literature and specifically here by former analyses of the SKB data. This assumption is nevertheless thoroughly tested by analyzing the fracture trace and lineament maps. Fracture traces range roughly between 0.5 m and 10 m - i e the usual extension of the sample outcrops. Between the raw data and final data used to compute the fracture size distribution from which the size distribution model will arise, several steps are necessary, in order to correct data from finite-size, topographical and sampling effects. More precisely, a particular attention is paid to fracture segmentation status and fracture linkage consistent with the DFN model expected. The fracture scaling trend observed over both sites displays finally a shape parameter k{sub t} close to 1.2 with a density term (alpha{sub 2d}) between 1.4 and 1.8. Only two outcrops clearly display a different trend with k{sub t} close to 3 and a density term (alpha{sub 2d}) between 2 and 3.5. The fracture lineaments spread over the range between 100 meters and a few kilometers. When compared with fracture trace maps, these datasets are already interpreted and the linkage process developed previously has not to be done. Except for the subregional lineament map from Forsmark, lineaments display a clear power-law trend with a shape parameter k{sub t} equal to 3 and a density term between 2 and 4.5. The apparent variation in scaling exponent, from the outcrop scale (k{sub t} = 1.2) on one side, to

Statistical methodology for discrete fracture model - including fracture size, orientation uncertainty together with intensity uncertainty and variability

International Nuclear Information System (INIS)

Darcel, C.; Davy, P.; Le Goc, R.; Dreuzy, J.R. de; Bour, O.

2009-11-01

Investigations led for several years at Laxemar and Forsmark reveal the large heterogeneity of geological formations and associated fracturing. This project aims at reinforcing the statistical DFN modeling framework adapted to a site scale. This leads therefore to develop quantitative methods of characterization adapted to the nature of fracturing and data availability. We start with the hypothesis that the maximum likelihood DFN model is a power-law model with a density term depending on orientations. This is supported both by literature and specifically here by former analyses of the SKB data. This assumption is nevertheless thoroughly tested by analyzing the fracture trace and lineament maps. Fracture traces range roughly between 0.5 m and 10 m - i e the usual extension of the sample outcrops. Between the raw data and final data used to compute the fracture size distribution from which the size distribution model will arise, several steps are necessary, in order to correct data from finite-size, topographical and sampling effects. More precisely, a particular attention is paid to fracture segmentation status and fracture linkage consistent with the DFN model expected. The fracture scaling trend observed over both sites displays finally a shape parameter k t close to 1.2 with a density term (α 2d ) between 1.4 and 1.8. Only two outcrops clearly display a different trend with k t close to 3 and a density term (α 2d ) between 2 and 3.5. The fracture lineaments spread over the range between 100 meters and a few kilometers. When compared with fracture trace maps, these datasets are already interpreted and the linkage process developed previously has not to be done. Except for the subregional lineament map from Forsmark, lineaments display a clear power-law trend with a shape parameter k t equal to 3 and a density term between 2 and 4.5. The apparent variation in scaling exponent, from the outcrop scale (k t = 1.2) on one side, to the lineament scale (k t = 2) on

Risk Factors Associated With Survival to Hospital Discharge of 54 Horses With Fractures of the Radius.

Science.gov (United States)

Stewart, Suzanne; Richardson, Dean; Boston, Ray; Schaer, Thomas P

2015-11-01

To determine (1) survival to discharge of horses with radial fractures (excluding osteochondral fragmentation of the distal aspect of the radius and stress fractures); and (2) risk factors affecting survival to hospital discharge in conservative and surgically managed fractures. Case series. Horses (n = 54). Medical records (1990-June 2012) and radiographs of horses admitted with radial fracture were reviewed. Horses with osteochondral fragmentation of the distal aspect of the radius or stress fractures were excluded. Evaluated risk factors were age, fracture configuration, surgical repair method, surgical duration, hospitalization time, implant failure rate, and surgical site infection (SSI) rate. Of 54 horses, overall survival to discharge was 50%. Thirteen (24%) were euthanatized on admission because of (1) fracture severity; (2) presence of an open fracture; or (3) financial constraints. Fourteen (26%) horses with minimally displaced incomplete fractures were conservatively managed and 12 (86%) survived to discharge. Twenty-seven (50%) horses had surgical treatment by open reduction and internal fixation (ORIF) and 15 (56%) survived to hospital discharge. Open fractures were significantly more likely to develop SSI (P = .008), which also resulted in a 17-fold increase in implant failure (P horses with an open fracture did not survive to discharge. Outcome was also adversely affected by age (P 168 minutes (P fractures is good. Young horses have a good prognosis survival to discharge for ORIF, whereas ORIF in adult horses has a poor prognosis and SSI strongly correlates with catastrophic implant failure. © Copyright 2015 by The American College of Veterinary Surgeons.

Overweight/obesity and underweight are both risk factors for osteoporotic fractures at different sites in Japanese postmenopausal women.

Science.gov (United States)

Tanaka, S; Kuroda, T; Saito, M; Shiraki, M

2013-01-01

This cohort study of 1,614 postmenopausal Japanese women followed for 6.7 years showed that overweight/obesity and underweight are both risk factors for fractures at different sites. Fracture risk assessment may be improved if fracture sites are taken into account and BMI is categorized. The effect of body mass index (BMI) on fracture at a given level of bone mineral density (BMD) is controversial, since varying associations between BMI and fracture sites have been reported. A total of 1,614 postmenopausal Japanese women were followed for 6.7 years in a hospital-based cohort study. Endpoints included incident vertebral, femoral neck, and long-bone fractures. Rate ratios were estimated by Poisson regression models adjusted for age, diabetes mellitus, BMD, prior fracture, back pain, and treatment by estrogen. Over a mean follow-up period of 6.7 years, a total of 254 clinical and 335 morphometric vertebral fractures, 48 femoral neck fractures, and 159 long-bone fractures were observed. Incidence rates of vertebral fracture in underweight and normal weight women were significantly lower than overweight or obese women by 0.45 (95 % confidence interval: 0.32 to 0.63) and 0.61 (0.50 to 0.74), respectively, if BMD and other risk factors were adjusted, and by 0.66 (0.48 to 0.90) and 0.70 (0.58 to 0.84) if only BMD was not adjusted. Incidence rates of femoral neck and long-bone fractures in the underweight group were higher than the overweight/obese group by 2.15 (0.73 to 6.34) and 1.51 (0.82 to 2.77) and were similar between normal weight and overweight/obesity. Overweight/obesity and underweight are both risk factors for fractures at different sites. Fracture risk assessment may be improved if fracture sites are taken into account and BMI is categorized.

Geological discrete-fracture network model (version 1) for the Olkiluoto site, Finland

International Nuclear Information System (INIS)

Fox, A.; Buoro, A.; Dahlbo, K.; Wiren, L.

2009-10-01

This report describes the methods, analyses, and conclusions of the modelling team in the production of a discrete-fracture network (DFN) model for the Olkiluoto Site in Finland. The geological DFN is a statistical model for stochastically simulating rock fractures and minor faults at a scale ranging from approximately 0.05 m to approximately 500 m; an upper scale limit is not expressly defined, but the DFN model explicitly excludes structures at deformation-zone scales (∼ 500 m) and larger. The DFN model is presented as a series of tables summarizing probability distributions for several parameters necessary for fracture modelling: fracture orientation, fracture size, fracture intensity, and associated spatial constraints. The geological DFN is built from data collected during site characterization (SC) activities at Olkiluoto, which is currently planned to function as a final deep geological repository for spent fuel and nuclear waste from the Finnish nuclear power program. Data used in the DFN analyses include fracture maps from surface outcrops and trenches (as of July 2007), geological and structural data from cored boreholes (as of July 2007), and fracture information collected during the construction of the main tunnels and shafts at the ONKALO laboratory (January 2008). The modelling results suggest that the rock volume at Olkiluoto surrounding the ONKALO tunnel can be separated into three distinct volumes (fracture domains): an upper block, an intermediate block, and a lower block. The three fracture domains are bounded horizontally and vertically by large deformation zones. Fracture properties, such as fracture orientation and relative orientation set intensity, vary between fracture domains. The rock volume at Olkiluoto is dominated by three distinct fracture sets: subhorizontally-dipping fractures striking north-northeast and dipping to the east, a subvertically-dipping fracture set striking roughly north-south, and a subverticallydipping fracture set

Hole Defects Affect the Dynamic Fracture Behavior of Nearby Running Cracks

Directory of Open Access Journals (Sweden)

R. S. Yang

2018-01-01

Full Text Available Effects of defects on the dynamic fracture behavior of engineering materials cannot be neglected. Using the experimental system of digital laser dynamic caustics, the effects of defects on the dynamic fracture behavior of nearby running cracks are studied. When running cracks propagate near to defects, the crack path deflects toward the defect; the degree of deflection is greater for larger defect diameters. When the running crack propagates away from the defect, the degree of deflection gradually reduces and the original crack path is restored. The intersection between the caustic spot and the defect is the direct cause of the running crack deflection; the intersection area determines the degree of deflection. In addition, the defect locally inhibits the dynamic stress intensity factor of running cracks when they propagate toward the defect and locally promotes the dynamic stress intensity factor of running cracks when they propagate away from the defect.

Factors that influence exercise activity among women post hip fracture participating in the Exercise Plus Program.

Science.gov (United States)

Resnick, Barbara; Orwig, Denise; D'Adamo, Christopher; Yu-Yahiro, Janet; Hawkes, William; Shardell, Michelle; Golden, Justine; Zimmerman, Sheryl; Magaziner, Jay

2007-01-01

Using a social ecological model, this paper describes selected intra- and interpersonal factors that influence exercise behavior in women post hip fracture who participated in the Exercise Plus Program. Model testing of factors that influence exercise behavior at 2, 6 and 12 months post hip fracture was done. The full model hypothesized that demographic variables; cognitive, affective, physical and functional status; pain; fear of falling; social support for exercise, and exposure to the Exercise Plus Program would influence self-efficacy, outcome expectations, and stage of change both directly and indirectly influencing total time spent exercising. Two hundred and nine female hip fracture patients (age 81.0 +/- 6.9), the majority of whom were Caucasian (97%), participated in this study. The three predictive models tested across the 12 month recovery trajectory suggest that somewhat different factors may influence exercise over the recovery period and the models explained 8 to 21% of the variance in time spent exercising. To optimize exercise activity post hip fracture, older adults should be helped to realistically assess their self-efficacy and outcome expectations related to exercise, health care providers and friends/peers should be encouraged to reinforce the positive benefits of exercise post hip fracture, and fear of falling should be addressed throughout the entire hip fracture recovery trajectory.

Pipe stress intensity factors and coupled depressurization and dynamic crack propagation. 1976 Annual report

International Nuclear Information System (INIS)

Emery, A.F.; Kobayashi, A.S.; Love, W.J.

1978-04-01

This report contains the description of predictive models for the initiation and propagation of cracks in pipes and the numerical results obtained. The initiation of the crack was studied by evaluating stress intensity factors under static conditions for a series of representative flaws. Three-dimensional static stress intensity factors were determined for quarter-elliptical cracks at the corner of a hole in an infinite plate and at the corner of a bore in a rotating disk. Semi-elliptical cracks for plates in bending and in pressurized and thermally stressed hollow cylinders were also evaluated. The stress fields, in the absence of a crack, were used in the ''alternating technique'' to compute the stress intensity factors along the crack front. Parametric studies were made to assess the effects of crack thickness, the ratio of the major and minor axes of the ellipse and the thickness of the cylinders or plates. These parametric results may be used to predict critical flaw sizes for the initiation of the running crack. The initiation and propagation of axial through cracks in pressurized pipes was studied by using an elastic-plastic finite different shell code coupled with a one-dimensional thermal-hydraulic code which computed the leakage through the crack opening and the depressurization of the fluid in the pipe. The effects of large deflections and different fluid pressure profiles were investigated. The results showed that the crack opening shape is dependent upon the fracture criterion used and upon the average pressure on the crack flaps, but not upon the specific pressure profile. The consideration of large deflections changed the opening size of the crack and through the coupling with the pipe pressures, strongly affected the crack tip speed. However, for equal crack lengths, there was little difference between calculations made for large and small deflection

Main factors causing intergranular and quasi-cleavage fractures at hydrogen-induced cracking in tempered martensitic steels

Science.gov (United States)

Kurokawa, Ami; Doshida, Tomoki; Hagihara, Yukito; Suzuki, Hiroshi; Takai, Kenichi

2018-05-01

Though intergranular (IG) and quasi-cleavage (QC) fractures have been widely recognized as typical fracture modes of the hydrogen-induced cracking in high-strength steels, the main factor has been unclarified yet. In the present study, the hydrogen content dependence on the main factor causing hydrogen-induced cracking has been examined through the fracture mode transition from QC to IG at the crack initiation site in the tempered martensitic steels. Two kinds of tempered martensitic steels were prepared to change the cohesive force due to the different precipitation states of Fe3C on the prior γ grain boundaries. A high amount of Si (H-Si) steel has a small amount of Fe3C on the prior austenite grain boundaries. Whereas, a low amount of Si (L-Si) steel has a large amount of Fe3C sheets on the grain boundaries. The fracture modes and initiations were observed using FE-SEM (Field Emission-Scanning Electron Microscope). The crack initiation sites of the H-Si steel were QC fracture at the notch tip under various hydrogen contents. While the crack initiation of the L-Si steel change from QC fracture at the notch tip to QC and IG fractures from approximately 10 µm ahead of the notch tip as increasing in hydrogen content. For L-Si steels, two possibilities are considered that the QC or IG fracture occurred firstly, or the QC and IG fractures occurred simultaneously. Furthermore, the principal stress and equivalent plastic strain distributions near the notch tip were calculated with FEM (Finite Element Method) analysis. The plastic strain was the maximum at the notch tip and the principle stress was the maximum at approximately 10 µm from the notch tip. The position of the initiation of QC and IG fracture observed using FE-SEM corresponds to the position of maximum strain and stress obtained with FEM, respectively. These findings indicate that the main factors causing hydrogen-induced cracking are different between QC and IG fractures.

Progressive fracture of polymer matrix composite structures: A new approach

Science.gov (United States)

Chamis, C. C.; Murthy, P. L. N.; Minnetyan, L.

1992-01-01

A new approach independent of stress intensity factors and fracture toughness parameters has been developed and is described for the computational simulation of progressive fracture of polymer matrix composite structures. The damage stages are quantified based on physics via composite mechanics while the degradation of the structural behavior is quantified via the finite element method. The approach account for all types of composite behavior, structures, load conditions, and fracture processes starting from damage initiation, to unstable propagation and to global structural collapse. Results of structural fracture in composite beams, panels, plates, and shells are presented to demonstrate the effectiveness and versatility of this new approach. Parameters and guidelines are identified which can be used as criteria for structural fracture, inspection intervals, and retirement for cause. Generalization to structures made of monolithic metallic materials are outlined and lessons learned in undertaking the development of new approaches, in general, are summarized.

Numerical examination of the factors controlling DNAPL migration through a single fracture.

Science.gov (United States)

Reynolds, D A; Kueper, B H

2002-01-01

The migration of five dense nonaqueous phase liquids (DNAPLs) through a single fracture in a clay aquitard was numerically simulated with the use of a compositional simulator. The effects of fracture aperture, fracture dip, matrix porosity, and matrix organic carbon content on the migration of chlorobenzene, 1,2-dichloroethylene, trichloroethylene, tetra-chloroethylene, and 1,2-dibromoethane were examined. Boundary conditions were chosen such that DNAPL entry into the system was allowed to vary according to the stresses applied. The aperture is the most important factor of those studied controlling the migration rate of DNAPL through a single fracture embedded in a clay matrix. Loss of mass to the matrix through diffusion does not significantly retard the migration rate of the DNAPL, particularly in larger aperture fractures (e.g., 50 microm). With time, the ratio of diffusive loss to the matrix to DNAPL flux into the fracture approaches an asymptotic value lower than unity. The implication is that matrix diffusion cannot arrest the migration of DNAPL in a single fracture. The complex relationships between density, viscosity, and solubility that, to some extent, govern the migration of DNAPL through these systems prevent accurate predictions without the use of numerical models. The contamination potential of the migrating DNAPL is significantly increased through the transfer of mass to the matrix. The occurrence of opposite concentration gradients within the matrix can cause dissolved phase contamination to exist in the system for more than 1000 years after the DNAPL has been completely removed from the fracture.

comparison of elastic-plastic FE method and engineering method for RPV fracture mechanics analysis

International Nuclear Information System (INIS)

Sun Yingxue; Zheng Bin; Zhang Fenggang

2009-01-01

This paper described the FE analysis of elastic-plastic fracture mechanics for a crack in RPV belt line using ABAQUS code. It calculated and evaluated the stress intensity factor and J integral of crack under PTS transients. The result is also compared with that by engineering analysis method. It shows that the results using engineering analysis method is a little larger than the results using FE analysis of 3D elastic-plastic fracture mechanics, thus the engineering analysis method is conservative than the elastic-plastic fracture mechanics method. (authors)

Pilot case-control investigation of risk factors for hip fractures in the urban Indian population

Directory of Open Access Journals (Sweden)

Malhotra Nidhi

2010-03-01

Full Text Available Abstract Background Despite the reported high prevalence of osteoporosis in India, there have been no previous studies examining the risk factors for hip fracture in the Indian population. Methods We carried out a case control investigation comprising 100 case subjects (57 women and 43 men admitted with a first hip fracture into one of three hospitals across New Delhi. The 100 controls were age and sex matched subjects who were either healthy visitors not related to the case patients or hospital staff. Information from all subjects was obtained through a questionnaire based interview. Results There was a significant increase in the number of cases of hip fracture with increasing age. There were significantly more women (57% than men (43%. Univariate analysis identified protective effects for increased activity, exercise, calcium and vitamin supplements, almonds, fish, paneer (cottage cheese, curd (plain yogurt, and milk. However, tea and other caffeinated beverages were significant risk factors. In women, hormone/estrogen therapy appeared to have a marginal protective effect. For all cases, decreased agility, visual impairment, long term medications, chronic illnesses increased the risk of hip fracture. The multivariate analysis confirmed a protective effect of increased activity and also showed a decrease in hip fracture risk with increasing body mass index (odds ratio (OR 0.024, 95% confidence interval (CI 0.006-0.10 & OR 0.81, 95% CI 0.68-0.97 respectively. Individuals who take calcium supplements have a decreased risk of hip fracture (OR 0.076; CI 0.017-0.340, as do individuals who eat fish (OR 0.094; CI 0.020-0.431, and those who eat paneer (OR 0.152; 0.031-0.741. Tea drinkers have a higher risk of hip fracture (OR 22.8; 95% CI 3.73-139.43. Difficulty in getting up from a chair also appears to be an important risk factor for hip fractures (OR 14.53; 95% CI 3.86-54.23. Conclusions In the urban Indian population, dietary calcium, vitamin D

Hip Fracture

Science.gov (United States)

... hip fractures in people of all ages. In older adults, a hip fracture is most often a result of a fall from a standing height. In people with very weak bones, a hip fracture can occur simply by standing on the leg and twisting. Risk factors The rate of hip fractures increases substantially with ...

Rib fractures after reirradiation plus hyperthermia for recurrent breast cancer. Predictive factors

Energy Technology Data Exchange (ETDEWEB)

Oldenborg, Sabine; Valk, Christel; Os, Rob van; Voerde Sive Voerding, Paul zum; Crezee, Hans; Tienhoven, Geertjan van; Rasch, Coen [University of Amsterdam, Department of Radiation Oncology, Z1-215, Academic Medical Center, Amsterdam (Netherlands); Oei, Bing; Venselaar, Jack [Institute Verbeeten (BVI), Tilburg (Netherlands); Randen, Adrienne van [University of Amsterdam (AMC), Department of Radiology Academic Medical Center, Amsterdam (Netherlands)

2016-04-15

Combining reirradiation (reRT) and hyperthermia (HT) has shown high therapeutic value for patients with locoregional recurrent breast cancer (LR). However, additional toxicity of reirradiation (e.g., rib fractures) may occur. The aim of this study is to determine the impact of potential risk factors on the occurrence of rib fractures. From 1982-2005, 234 patients were treated with adjuvant reRT + HT after surgery for LR. ReRT consisted typically of 8 fractions of 4 Gy twice a week, or 12 fractions of 3 Gy four times a week. A total of 118 patients were irradiated with abutted photon and electron fields. In all, 60 patients were irradiated using either one or alternating combinations of abutted AP electron fields. Hyperthermia was given once or twice a week. The 5-year infield local control (LC) rate was 70 %. Rib fractures were detected in 16 of 234 patients (actuarial risk: 7 % at 5 years). All rib fractures occurred in patients treated with a combination of photon and abutted electron fields (p = 0.000); in 15 of 16 patients fractures were located in the abutment regions. The other significant predictive factors for rib fractures were a higher fraction dose (p = 0.040), large RT fields, and treatment before the year 2000. ReRT + HT results in long-term LC. The majority of rib fractures were located in the photon/electron abutment area, emphasizing the disadvantage of field overlap. Large abutted photon/electron fields combined with 4 Gy fractions increase the number of rib fractures in this study group. However, as these factors were highly correlated no relative importance of the individual factors could be estimated. Increasing the number of HT sessions a week does not increase the risk of rib fractures. (orig.) [German] Der kombinierte Einsatz von Rebestrahlung (reRT) und Hyperthermie (HT) zeigt eine hohe Wirksamkeit bei Patienten mit lokoregional rezidiviertem Brustkrebs (LR). Jedoch koennen zusaetzliche toxische Effekte von reRT (z. B. Rippenfrakturen

Stress Concentration Factor and Stress Intensity Factor with U-notch and Crack in the Beam

Energy Technology Data Exchange (ETDEWEB)

Seo, Bo Seong; Lee, Kwang Ho [Kyungpook National Univ., Daegu (Korea, Republic of)

2016-05-15

The stress concentration factors and stress intensity factors for a simple beam and a cantilever are analyzed by using finite element method and photoelasticity. Using the analyzed results, the estimated graphs on stress concentration factors and stress intensity factors are obtained. To analyze stress concentration factors of notch, the dimensionless notch length H(height of specimen)/h=1.1-2 and dimensionless gap space r(radius at the notch tip)/h=0.1~0.5 are used, where h=H-c and c is the notch length. As the notch gap length increases and the gap decreases, the stress concentration factors increase. Stress concentration factors of a simple beam are greater than those of a cantilever beam. However, actually, the maximum stress values under a load, a notch length and a gap occur more greatly in the cantilever beam than in the simple beam. To analyze stress intensity factors, the normalized crack length α(crack length)/H=0.2~0.5 is used. As the length of the crack increases, the normalized stress intensity factors increase. The stress intensity factors under a constant load and a crack length occur more greatly in the cantilever beam than in the simple beam.

The use of the J* integral for non-linear fracture mechanics

International Nuclear Information System (INIS)

Hellen, T.K.

1976-09-01

The Griffith energy balance criterion, first postulated over 50 years ago, is still the basis of linear elastic fracture mechanics. From this, accurate numerical methods for establishing stress intensity factors and energy release rates have been developed. One such method involves path independent contour integrals about the crack tip. An improved contour integral, designated J* is discussed, and shown to have distinct advantages over others in non-linear strain situations. A number of examples are shown including fractures in thermo-plastic and creep situations. (author)

High prevalence of simultaneous rib and vertebral fractures in patients with hip fracture.

Science.gov (United States)

Lee, Bong-Gun; Sung, Yoon-Kyoung; Kim, Dam; Choi, Yun Young; Kim, Hunchul; Kim, Yeesuk

2017-02-01

The purpose was to evaluate the prevalence and location of simultaneous fracture using bone scans in patients with hip fracture and to determine the risk factors associated with simultaneous fracture. One hundred eighty two patients with hip fracture were reviewed for this study. Clinical parameters and bone mineral density (BMD) of the lumbar vertebra and femoral neck were investigated. To identify acute simultaneous fracture, a bone scan was performed at 15.4±4.1days after hip fracture. The prevalence and location of simultaneous fracture were evaluated, and multivariate logistic regression analysis was performed to determine the risk factors. Simultaneous fracture was observed in 102 of 182 patients, a prevalence of 56.0%. Rib fracture was the most common type of simultaneous fracture followed by rib with vertebral fracture. The BMD of the lumbar vertebra was significantly lower in patients with simultaneous fracture (p=0.044) and was identified as an independent risk factor (odds ratio: OR 0.05, 95% confidence interval: CI 0.01-0.57). The prevalence of simultaneous fracture was relatively high among patients with hip fracture, and BMD was significantly lower in patients with simultaneous fracture than in patients without it. Surgeons should be aware of the possibility of simultaneous fracture in patients with hip fracture. Copyright © 2016 Elsevier Ltd. All rights reserved.

A study on the fracture strength of steel fiber reinforced concrete structures with initial cracks

International Nuclear Information System (INIS)

Chang, Dong Il; Chai, Won Kyu; Lee, Myeong Gu

1991-01-01

Fracture tests were carried out in order to investigate the fracture behavior of SFRC(Steel Fiber Reinforced Concrete) structures with initial cracks. Sixty three SFRC beams were used in the tests. And the fracture mode, and relations between loading and mid-span deflection of the beams were observed. On the base of test results, fracture behavior of SFRC beams resulted from steel fiber content and initial crack length to beam depth ratio were found out, and the stress intensity factors, the modulus of rupture and the fracture energy of SFRC beams may then be calculated. According to the results of regression analysis, prediction formulas for the modulus of rupture and the fracture energy of SFRC beams are also suggested. (Author)

Fragility fracture risk and skeletal muscle function.

Science.gov (United States)

Pérez-López, F R; Ara, I

2016-01-01

Low-intensity fractures are closely related with age-related musculoskeletal disorders, including osteoporosis, muscle dysfunction and sarcopenia, age-related chronic diseases, and pharmacological treatments. During the last years, a huge amount of information and recommendations has been released in relation to bone metabolism and mineral content. Muscle dysfunction and sarcopenia are highly prevalent during the second half of life, especially in older subjects. The development of sarcopenia may be slowed through healthy lifestyle changes, which include adequate dietary protein, vitamin D and mineral intakes, and regular physical activity. Prevention of falls should be integral, including correction in major involved factors in order to reduce fragility fracture, improve quality of life and appropriately focus clinical and economic resources. Therefore, to obtain better results a global approach is needed to prevent age-related fractures in frail patients that is not only centered on bone metabolism and antiresorptive drugs.

Improved Formula for the Stress Intensity Factor of Semi-Elliptical Surface Cracks in Welded Joints under Bending Stress

Science.gov (United States)

Peng, Yang; Wu, Chao; Zheng, Yifu; Dong, Jun

2017-01-01

Welded joints are prone to fatigue cracking with the existence of welding defects and bending stress. Fracture mechanics is a useful approach in which the fatigue life of the welded joint can be predicted. The key challenge of such predictions using fracture mechanics is how to accurately calculate the stress intensity factor (SIF). An empirical formula for calculating the SIF of welded joints under bending stress was developed by Baik, Yamada and Ishikawa based on the hybrid method. However, when calculating the SIF of a semi-elliptical crack, this study found that the accuracy of the Baik-Yamada formula was poor when comparing the benchmark results, experimental data and numerical results. The reasons for the reduced accuracy of the Baik-Yamada formula were identified and discussed in this paper. Furthermore, a new correction factor was developed and added to the Baik-Yamada formula by using theoretical analysis and numerical regression. Finally, the predictions using the modified Baik-Yamada formula were compared with the benchmark results, experimental data and numerical results. It was found that the accuracy of the modified Baik-Yamada formula was greatly improved. Therefore, it is proposed that this modified formula is used to conveniently and accurately calculate the SIF of semi-elliptical cracks in welded joints under bending stress. PMID:28772527

Effect of Crack Tip Stress Concentration Factor on Fracture Resistance in Vacuum Environment

Science.gov (United States)

2015-01-20

indicate: (1) in all alloys, the fracture resistance is highest for blunt-notches (smaller Kt), and is lowest for fatigue -sharpened precracked...paths are transgranular and the fracture mode is ductile void coalescence in all cases, irrespective of the stress concentration factor. 20-01-2015...because of corrosion and/or various loading conditions such as fatigue , fretting, abrasion, etc. Also, the geometry of the structure may cause an

Assessment of fracture risk

International Nuclear Information System (INIS)

Kanis, John A.; Johansson, Helena; Oden, Anders; McCloskey, Eugene V.

2009-01-01

Fractures are a common complication of osteoporosis. Although osteoporosis is defined by bone mineral density at the femoral neck, other sites and validated techniques can be used for fracture prediction. Several clinical risk factors contribute to fracture risk independently of BMD. These include age, prior fragility fracture, smoking, excess alcohol, family history of hip fracture, rheumatoid arthritis and the use of oral glucocorticoids. These risk factors in conjunction with BMD can be integrated to provide estimates of fracture probability using the FRAX tool. Fracture probability rather than BMD alone can be used to fashion strategies for the assessment and treatment of osteoporosis.

Defect enhanced diffusion process and hydrogen delayed fracture in high strength steels

International Nuclear Information System (INIS)

Lung, C.W.; Mu Zaiqin.

1985-10-01

A defect enhanced diffusion model for hydrogen delayed fracture in high strength steels is suggested. It is shown that the rate of crack growth is dependent on the square or higher power of the stress intensity factor which is consistent with recent experiments. (author)

Experimental investigation of effect of specimen thickness on fracture toughness of Al-TiC composites

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M. S. Raviraj

2016-07-01

Full Text Available In this paper, the macro and micro-mechanical fracture behavior was studied for aluminum (Al6061 alloy matrix, reinforced with various proportions of TiC particles such as 3wt%, 5wt% and 7wt%. The Al6061-TiC metal matrix composites were produced by stir casting method to ensure uniform distribution of the TiC particulates in the Al matrix. The compact tension (CT specimens were machined according to ASTM E399 specifications to evaluate the fracture toughness for Al6061-TiC metal matrix composites. The CT specimens were machined for crack to width (a/W ratio of 0.5 and thickness to width (B/W ratios of 0.2 to 0.7 with an increment of 0.1. Load versus crack mouth opening displacement (CMOD data was plotted to estimate stress intensity factor KQ for various thicknesses of the specimen. The fracture toughness KIC was obtained by plotting stress intensity factor versus thickness to width ratios of specimen data. The fracture toughness of these composites varied between 16.4-19.2 MPa√m. Scanning Electron Microscope (SEM studies was made on the fractured surface of the specimens to understand the micro-mechanisms of failure involved in these composites. Void initiation is more significant in the matrix near the interface. The micro-cracks grow from these micro-voids and crack propagates by linking these micro cracks locating the crack path preferentially in the matrix adjacent to the interface indicating ductile fracture.

Stress intensity factors of corner cracks in two nozzle-cylinder intersections

International Nuclear Information System (INIS)

Kobayashi, A.S.; Polvanich, N.; Emery, A.F.; Love, W.J.

1977-01-01

In a recent paper, the authors presented the stress-intensity-magnification factors of a quarter-elliptical surface crack in a quarter-infinite solid and a circular crack approaching a reentry corner in a three-quarter infinite solid. These stress-intensity-magnification factors were used together with a curvature-correction factor to estimate the stress-intensity factor of a corner crack at a nozzle-cylinder intersection. Through appropriate superposition of the above stress-intensity-magnification factors, stress-intensity factors for hypothetical corner cracks at a nozzle-cylinder intersection subjected to internal pressure and transient thermal-stress loadings can be obtained. A description of a computer code based on this procedure as well as its applications in analyzing two corner-crack problems at a nozzle-cylinder intersection are discussed in this paper

Stress intensity factors of corner cracks in two nozzle-cylinder interactions

International Nuclear Information System (INIS)

Kobayashi, A.S.; Polvanich, N.; Emery, A.F.; Love, W.J.

1977-01-01

In a recent paper, the authors presented the stress-intensity-magnification factors of a quarter-elliptical surface crack in a quarter-infinite solid and a circular crack approaching a reentry corner in a three-quarter infinite solid. These stress-intensity-magnification factors were used together with a curvature-correction factor to estimate the stress-intensity factor of a corner crack at a nozzle-cylinder interaction. Through appropriate superposition of the above stress-intensity-magnification factors, stress-intensity factors for hypothetical corner cracks at a nozzle-cylinder intersection subjected to internal pressure and transient thermal-stress loadings can be obtained. A description of a computer code based on this procedure as well as its applications in analyzing two corner-crack probems at a nozzle-cylinder intersection are discussed in this paper. (Auth.)

Fracture history in osteoporosis: risk factors and its effect on quality of life.

Science.gov (United States)

Kuru, Pınar; Akyüz, Gülseren; Cerşit, Hülya Peynirci; Çelenlioğlu, Alp Eren; Cumhur, Ahmet; Biricik, Şefikcan; Kozan, Seda; Gökşen, Aylin; Özdemir, Mikail; Lüleci, Emel

2014-12-01

Fractures are one of the main outcomes in osteoporosis and have an important effect on the general health status. The purpose of this study was to determine the effect of major fracture history on quality of life. We also investigated the important risk factors and their effect on bone mineral density and fracture history. Cross-sectional study. We recruited 105 patients who were admitted to an osteoporosis outpatient clinic. Medical history, family history, calcium intake, physical activity level and biochemical tests were evaluated. Lumbar spine and femur neck bone mineral density were measured. The Qualeffo-41 questionnaire was also used for evaluating quality of life. The average age of the 105 patients included in the study was 56.04±13.73 and 89% of them were post-menopausal women. The average body mass index was 26.84±5.99, which means that the women were overweight. Also, 48.5% of the patients were diagnosed with osteoporosis and 51.5% of them were diagnosed as low bone density. A total of 34 patients had a fracture history with minor trauma and some of the patients had more than one fracture (12 ankle and foot, 10 forearm, 9 vertebral, 4 hand, 3 hip, 2 rib, 1 tibial). When the patients with and without fracture history were compared, the mean Qualeffo-41 score in patients with fracture was 43.85±2.57 and in the non-fracture group was 36.27±2.01. Forearm, ankle and foot fractures can be commonly seen in osteoporosis patients with fracture history. We suggest that it is important to recognise osteoporosis prior to first fracture and disease-specific quality of life assessment should be done.

Fracture History in Osteoporosis: Risk Factors and its Effect on Quality of Life

Directory of Open Access Journals (Sweden)

Pınar Kuru

2014-12-01

Full Text Available Background: Fractures are one of the main outcomes in osteoporosis and have an important effect on the general health status. Aims: The purpose of this study was to determine the effect of major fracture history on quality of life. We also investigated the important risk factors and their effect on bone mineral density and fracture history. Study Design: Cross-sectional study. Methods: We recruited 105 patients who were admitted to an osteoporosis outpatient clinic. Medical history, family history, calcium intake, physical activity level and biochemical tests were evaluated. Lumbar spine and femur neck bone mineral density were measured. The Qualeffo- 41 questionnaire was also used for evaluating quality of life. Results: The average age of the 105 patients included in the study was 56.04±13.73 and 89% of them were post-menopausal women. The average body mass index was 26.84±5.99, which means that the women were overweight. Also, 48.5% of the patients were diagnosed with osteoporosis and 51.5% of them were diagnosed as low bone density. A total of 34 patients had a fracture history with minor trauma and some of the patients had more than one fracture (12 ankle and foot, 10 forearm, 9 vertebral, 4 hand, 3 hip, 2 rib, 1 tibial. When the patients with and without fracture history were compared, the mean Qualeffo-41 score in patients with fracture was 43.85±2.57 and in the non-fracture group was 36.27±2.01. Conclusion: Forearm, ankle and foot fractures can be commonly seen in osteoporosis patients with fracture history. We suggest that it is important to recognise osteoporosis prior to first fracture and disease-specific quality of life assessment should be done.

Risk factors for decreased range of motion and poor outcomes in open periarticular elbow fractures.

Science.gov (United States)

Dickens, Jonathan F; Wilson, Kevin W; Tintle, Scott M; Heckert, Reed; Gordon, Wade T; D'Alleyrand, Jean-Claude G; Potter, Benjamin K

2015-04-01

The purpose of this study was to identify risk factors present at the time of injury that predict poor functional outcomes and heterotopic ossification (HO) in open periarticular elbow fractures. We performed a retrospective review of 136 combat-related open elbow fractures from 2003 to 2010. Patient demographics, injury characteristics, treatment variables, and complications were recorded. Functional outcomes were analyzed to determine range of motion (ROM) and Mayo Elbow Performance Score (MEPS). Secondary outcome measures included the development of HO, return to duty, and revision operation. At a median 2.7 years from injury the median MEPS was 67.8 (range 30-100) with an average ulnohumeral arc motion of 89°. Bipolar fractures, with periarticular fractures on both sides of the elbow and at least one side containing intra-articular extension, were independently associated with decreased ulnohumeral motion (p=0.02) and decreased MEPS (pROM included more severe osseous comminution (p=0.001), and increased time to definitive fixation (p=0.03) and HO (p=0.02). More severe soft tissue injury (Gustilo and Anderson fracture type, p=0.02), peripheral nerve injury (p=0.04), and HO (p=0.03) were independently associated with decreased MEPS. HO developed in 65% (89/136) of extremities and was associated with more severe Orthopaedic Trauma Association (OTA) fracture type (p=0.01) and escalating Gustilo and Anderson fracture classification (p=0.049). In the largest series of open elbow fractures, we identified risk factors that portend a poor clinical outcome and decreased ROM. Bipolar elbow fractures, which have not previously been associated with worse results, are particularly prone to decreased ROM and worse outcomes. Prognostic level IV. Published by Elsevier Ltd.

The application of post yield fracture methodology to the evaluation of large structures

International Nuclear Information System (INIS)

Landes, J.D.

1979-01-01

The objective of this work is to determine how to use small specimens test results to measure fracture toughness values for application to the evaluation of large structural components. Linear elastic fracture mechanics concepts based on the crack tip stress intensity factor, K, have been extended into the post yield regime by the use of elastic-plastic characterizing parameters such as J integral and COD. One of the primary applications of this technology is the determination of fracture toughness values from small specimens tests taken primarily in the post yield regime which can be used to evaluate structures operating in an essentially linear elastic regime. The fracture toughness values may be either conservative or unconservative depending on the fracture mode; extreme care must be taken in interpretting these results. (orig.)

Benign compression fractures of the spine: signal patterns

International Nuclear Information System (INIS)

Ryu, Kyung Nam; Choi, Woo Suk; Lee, Sun Wha; Lim, Jae Hoon

1992-01-01

Fifteen patients with 38 compression fractures of the spine underwent magnetic resonance(MR) imaging. We retrospectively evaluated MR images in those benign compression fractures. MR images showed four patterns in T1-weighted images. MR imaging patterns were normal signal(21), band like low signal(8), low signal with preservation of peripheral portion of the body(8), and diffuse low signal through the vertebral body(1). The low signal portions were changed to high signal intensities in T2-weighted images. In 7 of 15 patients (11 compression fractures), there was a history of trauma, and the remaining 8 patients (27 compression fractures) had no history of trauma. Benign compression fractures of trauma, remained 8 patients (27 compression fractures) were non-traumatic. Benign compression fractures of the spine reveal variable signal intensities in MR imagings. These patterns of benign compression fractures may be useful in interpretation of MR imagings of the spine

Application of the boundary elements method for modeling of the fracture of cylindrical bodies by hydraulic fracturing

Science.gov (United States)

Legan, M. A.; Blinov, V. A.; Larichkin, A. Yu; Novoselov, A. N.

2017-10-01

Experimental study of hydraulic fracturing of thick-walled cylinders with a central circular hole was carried out using the machine that creates a high oil pressure. Experiments on the compression fracture of the solid cylinders by diameter and rectangular parallelepipeds perpendicular to the ends were carried out with a multipurpose test machine Zwick / Roell Z100. Samples were made of GF-177 material based on cement. Ultimate stresses in the material under study were determined for three types of stress state: under compression, with a pure shear on the surface of the hole under frecking conditions and under a compound stress state under conditions of diametral compression of a solid cylinder. The value of the critical stress intensity factor of GF-177 material was obtained. The modeling of the fracturing process taking into account the inhomogeneity of the stress state near the hole was carried out using the boundary elements method (in the variant of the fictitious load method) and the gradient fracture criterion. Calculation results of the ultimate pressure were compared with values obtained analytically on the basis of the Lame solution and with experimental data.

Persistent hyperparathyroidism is a major risk factor for fractures in the five years after kidney transplantation.

Science.gov (United States)

Perrin, P; Caillard, S; Javier, R M; Braun, L; Heibel, F; Borni-Duval, C; Muller, C; Olagne, J; Moulin, B

2013-10-01

The risk of fractures after kidney transplantation is high. Hyperparathyroidism frequently persists after successful kidney transplantation and contributes to bone loss, but its impact on fracture has not been demonstrated. This longitudinal study was designed to evaluate hyperparathyroidism and its associations with mineral disorders and fractures in the 5 posttransplant years. We retrospectively analyzed 143 consecutive patients who underwent kidney transplantation between August 2004 and April 2006. The biochemical parameters were determined at transplantation and at 3, 12 and 60 months posttransplantation, and fractures were recorded. The median intact parathyroid hormone (PTH) level was 334 ng/L (interquartile 151-642) at the time of transplantation and 123 ng/L (interquartile 75-224) at 3 months. Thirty fractures occurred in 22 patients. The receiver operating characteristic (ROC) curve analysis for PTH at 3 months (area under the ROC curve = 0.711, p = 0.002) showed that a good threshold for predicting fractures was 130 ng/L (sensitivity = 81%, specificity = 57%). In a multivariable analysis, independent risk factors for fracture were PTH >130 ng/L at 3 months (adjusted hazard ratio [AHR] = 7.5, 95% CI 2.18-25.50), and pretransplant osteopenia (AHR = 2.7, 95% CI 1.07-7.26). In summary, this study demonstrates for the first time that persistent hyperparathyroidism is an independent risk factor for fractures after kidney transplantation. © Copyright 2013 The American Society of Transplantation and the American Society of Transplant Surgeons.

What Factors are Associated With a Surgical Site Infection After Operative Treatment of an Elbow Fracture?

Science.gov (United States)

Claessen, Femke M A P; Braun, Yvonne; van Leeuwen, Wouter F; Dyer, George S; van den Bekerom, Michel P J; Ring, David

2016-02-01

Surgical site infections are one of the more common major complications of elbow fracture surgery and can contribute to other adverse outcomes, prolonged hospital stays, and increased healthcare costs. We asked: (1) What are the factors associated with a surgical site infection after elbow fracture surgery? (2) When taking the subset of closed elbow fractures only, what are the factors associated with a surgical site infection? (3) What are the common organisms isolated from an elbow infection after open treatment? One thousand three hundred twenty adult patients underwent surgery for an elbow fracture between January 2002 and July 2014 and were included in our study. Forty-eight of 1320 patients (4%) had a surgical site infection develop. Thirty-four of 1113 patients with a closed fracture (3%) had a surgical site infection develop. For all elbow fractures, use of plate and screw fixation (adjusted odds ratio [OR]= 2.2; 95% CI, 1.0-4.5; p = 0.041) and use of external fixation before surgery (adjusted OR = 4.7; 95% CI, 1.1-21; p = 0.035) were associated with higher infection rates. When subset analysis was performed for closed fractures, only smoking (adjusted OR = 2.2; 95% CI, 1.1-4.5; p = 0.023) was associated with higher infection rates. Staphylococcus aureus was the most common bacteria cultured (59%). The only modifiable risk factor for a surgical site infection after open reduction and internal fixation was cigarette smoking. Plate fixation and temporary external fixation are likely surrogates for more complex injuries, therefore no recommendations should be inferred from this association. Surgeons should counsel patients who smoke. Level IV, prognostic study.

Estimation of possibility of brittle fracture in high pressure boiler drums

International Nuclear Information System (INIS)

Grin', E.A.

2005-01-01

Paper presents the results of analysis of the problem to ensure brittle strength of high pressure boiler drums made with application of the present-day methods of linear and nonlinear fracture mechanics. The charts of the temperature boundaries of brittle fracture and of the critical factors of stress intensity plotted depending on the actual properties of the material and on dimensions of flaws are presented for standard size drums made of 22K and 16GNM steels. In the paper there are some examples of the practical application of the given charts [ru

A Numerical Study of Factors Affecting Fracture-Fluid Cleanup and Produced Gas/Water in Marcellus Shale: Part II

Energy Technology Data Exchange (ETDEWEB)

Seales, Maxian B.; Dilmore, Robert; Ertekin, Turgay; Wang, John Yilin

2017-04-01

Horizontal wells combined with successful multi-stage hydraulic fracture treatments are currently the most established method for effectively stimulating and enabling economic development of gas bearing organic-rich shale formations. Fracture cleanup in the Stimulated Reservoir Volume (SRV) is critical to stimulation effectiveness and long-term well performance. However, fluid cleanup is often hampered by formation damage, and post-fracture well performance frequently falls below expectations. A systematic study of the factors that hinder fracture fluid cleanup in shale formations can help optimize fracture treatments and better quantify long term volumes of produced water and gas. Fracture fluid cleanup is a complex process influenced by multi-phase flow through porous media (relative permeability hysteresis, capillary pressure etc.), reservoir rock and fluid properties, fracture fluid properties, proppant placement, fracture treatment parameters, and subsequent flowback and field operations. Changing SRV and fracture conductivity as production progresses further adds to the complexity of this problem. Numerical simulation is the best, and most practical approach to investigate such a complicated blend of mechanisms, parameters, their interactions, and subsequent impact on fracture fluid cleanup and well deliverability. In this paper, a 3-dimensional, 2-phase, dual-porosity model was used to investigate the impact of multiphase flow, proppant crushing, proppant diagenesis, shut-in time, reservoir rock compaction, gas slippage, and gas desorption on fracture fluid cleanup, and well performance in Marcellus shale. The research findings have shed light on the factors that substantially constrains efficient fracture fluid cleanup in gas shales, and provided guidelines for improved fracture treatment designs and water management.

Major factors controlling fracture development in the Middle Permian Lucaogou Formation tight oil reservoir, Junggar Basin, NW China

Science.gov (United States)

Zhang, Chen; Zhu, Deyu; Luo, Qun; Liu, Luofu; Liu, Dongdong; Yan, Lin; Zhang, Yunzhao

2017-09-01

Natural fractures in seven wells from the Middle Permian Lucaogou Formation in the Junggar Basin were evaluated in light of regional structural evolution, tight reservoir geochemistry (including TOC and mineral composition), carbon and oxygen isotopes of calcite-filled fractures, and acoustic emission (AE). Factors controlling the development of natural fractures were analyzed using qualitative and/or semi-quantitative techniques, with results showing that tectonic factors are the primary control on fracture development in the Middle Permian Lucaogou Formation of the Junggar Basin. Analyses of calcite, dolomite, and TOC show positive correlations with the number of fractures, while deltaic lithofacies appear to be the most favorable for fracture development. Mineral content was found to be a major control on tectonic fracture development, while TOC content and sedimentary facies mainly control bedding fractures. Carbon and oxygen isotopes vary greatly in calcite-filled fractures (δ13C ranges from 0.87‰ to 7.98‰, while δ18O ranges from -12.63‰ to -5.65‰), indicating that fracture development increases with intensified tectonic activity or enhanced diagenetic alteration. By analyzing the cross-cutting relationships of fractures in core, as well as four Kaiser Effect points in the acoustic emission curve, we observed four stages of tectonic fracture development. First-stage fractures are extensional, and were generated in the late Triassic, with calcite fracture fills formed between 36.51 °C and 56.89 °C. Second-stage fractures are shear fractures caused by extrusion stress from the southwest to the northeast, generated by the rapid uplift of the Tianshan in the Middle and Late Jurassic; calcite fracture fills formed between 62.91 °C and 69.88 °C. Third-stage fractures are NNW-trending shear fractures that resulted from north-south extrusion and thrusting in a foreland depression along the front of the Early Cretaceous Bogda Mountains. Calcite fracture

Could whole body vibration exercises influence the risk factors for fractures in women with osteoporosis?

Directory of Open Access Journals (Sweden)

Eloá Moreira-Marconi

2016-12-01

Conclusions: Although the paucity of research regarding direct effects of WBV in decreasing fractures, WBV could be a feasible and effective way to modify well-recognized risk factors for falls and fractures, improvements in some aspects of neuromuscular function and balance. More studies have to be performed establish protocols with well controlled parameters.

Application of fracture mechanics to fatigue in pressure vessels

International Nuclear Information System (INIS)

Ghavami, K.

1982-01-01

The methods of application of fracture mechanics to predict fatigue crack propagation in welded structures and pressure vessels are described with the following objectives: i) To identify the effect of different variables such as crack tip plasticity, free surface, finite plate thickness, stress concentration and type of the structure, on the magnitude of stress intensity factor K in Welded joint. ii) To demonstrate the use of fracture mechanics for analysing fatigue crack propagation data. iii) To show how a law of fatigue crack propagation based on fracure mechanics, may be used to predict fatigue behavior of welded structures such as pressure vessel. (Author) [pt

Factors that influence exercise activity among women post hip fracture participating in the Exercise Plus Program

OpenAIRE

Resnick, Barbara; Orwig, Denise; D?Adamo, Christopher; Yu-Yahiro, Janet; Hawkes, William; Shardell, Michelle; Golden, Justine; Zimmerman, Sheryl; Magaziner, Jay

2007-01-01

Using a social ecological model, this paper describes selected intra- and interpersonal factors that influence exercise behavior in women post hip fracture who participated in the Exercise Plus Program. Model testing of factors that influence exercise behavior at 2, 6 and 12 months post hip fracture was done. The full model hypothesized that demographic variables; cognitive, affective, physical and functional status; pain; fear of falling; social support for exercise, and exposure to the Exer...

External fixation of tibial pilon fractures and fracture healing.

Science.gov (United States)

Ristiniemi, Jukka

2007-06-01

Distal tibial fractures are rare and difficult to treat because the bones are subcutaneous. External fixation is commonly used, but the method often results in delayed union. The aim of the present study was to find out the factors that affect fracture union in tibial pilon fractures. For this purpose, prospective data collection of tibial pilon fractures was carried out in 1998-2004, resulting in 159 fractures, of which 83 were treated with external fixation. Additionally, 23 open tibial fractures with significant > 3 cm bone defect that were treated with a staged method in 2000-2004 were retrospectively evaluated. The specific questions to be answered were: What are the risk factors for delayed union associated with two-ring hybrid external fixation? Does human recombinant BMP-7 accelerate healing? What is the role of temporary ankle-spanning external fixation? What is the healing potential of distal tibial bone loss treated with a staged method using antibiotic beads and subsequent autogenous cancellous grafting compared to other locations of the tibia? The following risk factors for delayed healing after external fixation were identified: post-reduction fracture gap of >3 mm and fixation of the associated fibula fracture. Fracture displacement could be better controlled with initial temporary external fixation than with early definitive fixation, but it had no significant effect on healing time, functional outcome or complication rate. Osteoinduction with rhBMP-7 was found to accelerate fracture healing and to shorten the sick leave. A staged method using antibiotic beads and subsequent autogenous cancellous grafting proved to be effective in the treatment of tibial bone loss. Healing potential of the bone loss in distal tibia was at least equally good as in other locations of the tibia.

[Pregnancy and lactation are not risk factors for osteoporosis or fractures].

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Karlsson, Magnus K; Ahlborg, Henrik G; Karlsson, Caroline

Observational and case control studies infer that a pregnancy and a period of lactation are followed by loss in bone mass of up to 5%. The reason for this loss is virtually impossible to conclude as so many factors known to influence the bone mass undergo changes during a pregnancy and lactation. The increased calcium demand, changed nutritional habits, reduced smoking and alcohol consumption seen in many women during these periods, the changes in body weight and fat content, the changed level of physical activity and the changed levels of hormones with potential to influence the bone metabolism could all influence the bone mass. Most studies also report that the deficit in "bone mass" normalises after weaning. Multiple pregnancies and long total duration of lactation can not be regarded as risk factors for osteoporosis and fragility fractures as most reports indicate that women with multiple pregnancies have similar or higher bone mass and similar or lower fracture incidence than their peers with no children.

Immediate versus delayed intramedullary nailing for open fractures of the tibial shaft: a multivariate analysis of factors affecting deep infection and fracture healing.

Science.gov (United States)

Yokoyama, Kazuhiko; Itoman, Moritoshi; Uchino, Masataka; Fukushima, Kensuke; Nitta, Hiroshi; Kojima, Yoshiaki

2008-10-01

The purpose of this study was to evaluate contributing factors affecting deep infection and fracture healing of open tibia fractures treated with locked intramedullary nailing (IMN) by multivariate analysis. We examined 99 open tibial fractures (98 patients) treated with immediate or delayed locked IMN in static fashion from 1991 to 2002. Multivariate analyses following univariate analyses were derived to determine predictors of deep infection, nonunion, and healing time to union. The following predictive variables of deep infection were selected for analysis: age, sex, Gustilo type, fracture grade by AO type, fracture location, timing or method of IMN, reamed or unreamed nailing, debridement time (6 h), method of soft-tissue management, skin closure time (1 week), existence of polytrauma (ISS or =18), existence of floating knee injury, and existence of superficial/pin site infection. The predictive variables of nonunion selected for analysis was the same as those for deep infection, with the addition of deep infection for exchange of pin site infection. The predictive variables of union time selected for analysis was the same as those for nonunion, excluding of location, debridement time, and existence of floating knee and superficial infection. Six (6.1%; type II Gustilo n=1, type IIIB Gustilo n=5) of the 99 open tibial fractures developed deep infections. Multivariate analysis revealed that timing or method of IMN, debridement time, method of soft-tissue management, and existence of superficial or pin site infection significantly correlated with the occurrence of deep infection (Prate in type IIIB + IIIC was significantly higher than those in type I + II and IIIA (P = 0.016). Nonunion occurred in 17 fractures (20.3%, 17/84). Multivariate analysis revealed that Gustilo type, skin closure time, and existence of deep infection significantly correlated with occurrence of nonunion (P < 0.05). Gustilo type and existence of deep infection were significantly correlated

Stress intensity factors of eccentric cracks in bi-materials plate under mode I loading

Energy Technology Data Exchange (ETDEWEB)

Ismail, A. E. [Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Batu Pahat, Johor (Malaysia)

2015-05-15

Bi-material plates were generally used to joint electronic devices or mechanical components requiring dissimilar materials to be attached. During services, mechanical failure can be occurred due to the formation of cracks at the interfacial joint or away from the centre. Generally, linear elastic fracture mechanics approach is used to characterize these cracks based on stress intensity factors (SIF). Based on the literature survey, the SIFs for the central cracks were easily available. However, the SIFs for eccentric cracks were difficult to obtain. Therefore, this paper presented the SIFs for eccentric cracks subjected to mode I tension loading. Three important parameters were used such as relative crack depth, a/L, relative offset distance, b/L and elastic mismatch, E{sub 1}/E{sub 2} or α. It was found that such parameters significantly affected the characteristic of SIFs and it was depend on the location of cracks.

Spinal cord injuries related to cervical spine fractures in elderly patients: factors affecting mortality.

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Daneshvar, Parham; Roffey, Darren M; Brikeet, Yasser A; Tsai, Eve C; Bailey, Chris S; Wai, Eugene K

2013-08-01

Spinal cord injuries (SCIs) related to cervical spine (C-spine) fractures can cause significant morbidity and mortality. Aggressive treatment often required to manage instability associated with C-spine fractures is complicated and hazardous in the elderly population. To determine the mortality rate of elderly patients with SCIs related to C-spine fractures and identify factors that contribute toward a higher risk for negative outcomes. Retrospective cohort study at two Level 1 trauma centers. Thirty-seven consecutive patients aged 60 years and older who had SCIs related to C-spine fractures. Level of injury, injury severity, preinjury medical comorbidities, treatment (operative vs. nonoperative), and cause of death. Hospital medical records were reviewed independently. Baseline radiographs and computed tomography or magnetic resonance imaging scans were examined to permit categorization according to the mechanistic classification by Allen and Ferguson of subaxial C-spine injuries. Univariate logistic regression analyses were performed to identify factors related to in-hospital mortality and ambulation at discharge. There were no funding sources or potential conflicts of interest to disclose. The in-hospital mortality rate was 38%. Respiratory failure was the leading cause of death. Preinjury medical comorbidities, age, and operative versus nonoperative treatment did not affect mortality. Injury level at or above C4 was associated with a 7.1 times higher risk of mortality compared with injuries below C4 (p=.01). Complete SCI was associated with a 5.1 times higher risk of mortality compared with incomplete SCI (p=.03). Neurological recovery was uncommon. Apart from severity of initial SCI, no other factor was related to ambulatory disposition at discharge. In this elderly population, neurological recovery was poor and the in-hospital mortality rate was high. The strongest risk factors for mortality were injury level and severity of SCI. Although each case of SCI

Predicting Early Mortality After Hip Fracture Surgery: The Hip Fracture Estimator of Mortality Amsterdam.

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Karres, Julian; Kieviet, Noera; Eerenberg, Jan-Peter; Vrouenraets, Bart C

2018-01-01

Early mortality after hip fracture surgery is high and preoperative risk assessment for the individual patient is challenging. A risk model could identify patients in need of more intensive perioperative care, provide insight in the prognosis, and allow for risk adjustment in audits. This study aimed to develop and validate a risk prediction model for 30-day mortality after hip fracture surgery: the Hip fracture Estimator of Mortality Amsterdam (HEMA). Data on 1050 consecutive patients undergoing hip fracture surgery between 2004 and 2010 were retrospectively collected and randomly split into a development cohort (746 patients) and validation cohort (304 patients). Logistic regression analysis was performed in the development cohort to determine risk factors for the HEMA. Discrimination and calibration were assessed in both cohorts using the area under the receiver operating characteristic curve (AUC), the Hosmer-Lemeshow goodness-of-fit test, and by stratification into low-, medium- and high-risk groups. Nine predictors for 30-day mortality were identified and used in the final model: age ≥85 years, in-hospital fracture, signs of malnutrition, myocardial infarction, congestive heart failure, current pneumonia, renal failure, malignancy, and serum urea >9 mmol/L. The HEMA showed good discrimination in the development cohort (AUC = 0.81) and the validation cohort (AUC = 0.79). The Hosmer-Lemeshow test indicated no lack of fit in either cohort (P > 0.05). The HEMA is based on preoperative variables and can be used to predict the risk of 30-day mortality after hip fracture surgery for the individual patient. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Stress analysis of implant-bone fixation at different fracture angle

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Izzawati, B.; Daud, R.; Afendi, M.; Majid, MS Abdul; Zain, N. A. M.; Bajuri, Y.

2017-10-01

Internal fixation is a mechanism purposed to maintain and protect the reduction of a fracture. Understanding of the fixation stability is necessary to determine parameters influence the mechanical stability and the risk of implant failure. A static structural analysis on a bone fracture fixation was developed to simulate and analyse the biomechanics of a diaphysis shaft fracture with a compression plate and conventional screws. This study aims to determine a critical area of the implant to be fractured based on different implant material and angle of fracture (i.e. 0°, 30° and 45°). Several factors were shown to influence stability to implant after surgical. The stainless steel, (S. S) and Titanium, (Ti) screws experienced the highest stress at 30° fracture angle. The fracture angle had a most significant effect on the conventional screw as compared to the compression plate. The stress was significantly higher in S.S material as compared to Ti material, with concentrated on the 4th screw for all range of fracture angle. It was also noted that the screws closest to the intense concentration stress areas on the compression plate experienced increasing amounts of stress. The highest was observed at the screw thread-head junction.

Fear of falling in patients with hip fractures: prevalence and related psychological factors.

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Visschedijk, Jan; van Balen, Romke; Hertogh, Cees; Achterberg, Wilco

2013-03-01

To determine the prevalence of fear of falling (FoF) in patients after a hip fracture, to investigate the relation with time after fracture, and to assess associations between FoF and other psychological factors. Cross-sectional study performed between September 2010 and March 2011 in elderly patients after a hip fracture. Ten postacute geriatric rehabilitation wards in Dutch nursing homes. A total of 100 patients aged ≥65 years with a hip fracture admitted to a geriatric rehabilitation ward. FoF and related concepts such as falls-related self-efficacy, depression, and anxiety were measured by means of self-assessment instruments. Of all patients, 36% had a little FoF and 27% had quite a bit or very much FoF. Scores on the Falls Efficacy Scale-International were 30.6 in the first 4 weeks after hip fracture, 35.6 in the second 4 weeks, and 29.4 in the period ≥8 weeks after fracture. In these 3 periods, the prevalence rates of FoF were 62%, 68%, and 59%, respectively. Significant correlations were found between FoF and anxiety (P falls-related self-efficacy. During rehabilitation, FoF is greatest in the second 4 weeks after hip fracture. More studies are needed to explore the determinants of FoF and develop interventions to reduce FoF and improve outcome after rehabilitation. Copyright © 2013. Published by Elsevier Inc.

Fracture Sealing in Shales: Geological and Geochemical Factors

International Nuclear Information System (INIS)

Cathelineau, Michel

2001-01-01

The so-called self-sealing processes can be re-examined at the light of geological and geochemical consideration about the past history of the rocks. The concept of 'self sealing' needs to consider the formation and the sealing of fractures, especially three main stages: (i) the initiation of the fracture (development of micro-cracks initiated from previous heterogeneities up to fracturing), ii) the fracturing processes which occur generally at depth in presence of a fluid phase, iii) the healing or sealing of the fractures which corresponds basically to two main processes: a restoration of the initial permeability of the rock block by reducing the transmissivity of the discontinuity down to values equivalent to that of the homogeneous medium before fracturing, or the sealing of the open discontinuity by precipitation of newly formed minerals. In the latter case, the evolution of the open fracture is driven by re-arrangement of particles or precipitation of newly formed material, either by dissolution/crystallisation processes or by crystallisation from the percolating fluids (advective processes). Such processes are governed by chemical processes, especially the rate of precipitation of minerals which depends of the degree of saturation with respect to the mineral, and the kinetics of precipitation. (author)

Elastic-plastic Fracture Mechanics Assessment of nozzle corners submitted to thermal shock loading

International Nuclear Information System (INIS)

Chapuliot, S.; Marie, S.

2016-01-01

This paper focuses on the development of a simplified analytical scheme for the elastic-plastic Fracture Mechanics Assessment of large nozzle corners. Within that frame, following the specific numerical effort performed for the definition of a Stress Intensity Factor compendium, complementary elastic-plastic developments are proposed here for the consideration of the thermal shock loading in the elastic-plastic domain: this type of loading is a major loading for massive structures such as nozzle corners of large components. Thus, an important numerical was performed in order to extend the applicability domain of existing analytical schemes to those complex geometries. The final formulation is a simple one, applicable to a large variety of materials and geometrical configurations as long as the structure is large and the defect remains small in comparison to the internal radius of the nozzle. - Highlights: • Fracture Mechanics Assessment of large nozzle corners. • Elastic-plastic Stress Intensity Factor determination under thermal shock loading. • Semi-analytical schemes for J calculation.

Serial MRI findings of osteoporotic vertebral fractures in the thoracic and lumbar spine

International Nuclear Information System (INIS)

Hamada, Yoshitaka; Henmi, Tatsuhiko; Sakamoto, Rintaro; Hiasa, Masahiko

1998-01-01

The prognosis of osteoporotic vertebral fractures in the thoracic and lumbar spine was studied by serial MRI findings. This study covered 80 vertebrae in 69 patients treated conservatively and followed-up for more than six months (23 males and 46 females, average age 70 yrs). Group A, characterized by poor diagnostic imaging, consisted of patients who had both severely collapsed vertebra which was progressive in the lateral roentgenogram and delayed improvement in MRI signal intensities. Group B, consisting of poor clinical prognosis, comprised patients with persistent back pain. The predictive factors for Group A were found to be T 1 -low finding over the entire vertebra within one month after injury and fractures of Th 12 or L 1 vertebra. Areas of T 1 -low and T 2 -low intensity adjacent to the vertebral disc presented no improvement in signal intensity and often caused persistent back pain. (author)

Application of Fracture Mechanics to Specify the Proof Load Factor for Clamp Band Systems of Launch Vehicles

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Singaravelu, J.; Sundaresan, S.; Nageswara Rao, B.

2013-04-01

This article presents a methodology for evaluation of the proof load factor (PLF) for clamp band system (CBS) made of M250 Maraging steel following fracture mechanics principles.CBS is most widely used as a structural element and as a separation system. Using Taguchi's design of experiments and the response surface method (RSM) the compact tension specimens were tested to establish an empirical relation for the failure load ( P max) in terms of the ultimate strength, width, thickness, and initial crack length. The test results of P max closely matched with the developed RSM empirical relation. Crack growth rates of the maraging steel in different environments were examined. Fracture strength (σf) of center surface cracks and through-crack tension specimens are evaluated utilizing the fracture toughness ( K IC). Stress induced in merman band at flight loading conditions is evaluated to estimate the higher load factor and PLF. Statistical safety factor and reliability assessments were made for the specified flaw sizes useful in the development of fracture control plan for CBS of launch vehicles.

Magnetic resonance imaging in osteomalacic insufficiency fractures of the pelvis

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Kanberoglu, K. [Department of Radiology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul (Turkey)]. E-mail: zkanber@istanbul.edu.tr; Kantarci, F. [Department of Radiology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul (Turkey); Cebi, D. [Department of Radiology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul (Turkey); Yilmaz, M.H. [Department of Radiology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul (Turkey); Kurugoglu, S. [Department of Radiology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul (Turkey); Bilici, A. [Department of Internal Medicine, Cerrahpasa Medical Faculty, Istanbul University, Istanbul (Turkey); Koyuncu, H. [Department of Physical Medicine and Rehabilitation, Cerrahpasa Medical Faculty, Istanbul University, Istanbul (Turkey)

2005-01-01

AIMS: To report the magnetic resonance imaging (MRI) findings of osteomalacic insufficiency fractures of the pelvis. MATERIALS AND METHODS: In all, 12 persons presenting with chronic pelvic pain and with a definitive diagnosis of osteomalacia (OM) were enrolled in this study. Radiological work-up included direct radiographs (n=12), computed tomography (n=5), scintigraphy n=12) and MRI (n=12). The location of the insufficiency fractures and corresponding MRI appearances were evaluated. Depending on the presence or absence of signal intensity around the fractures, the lesions were grouped into active and chronic forms. RESULTS: A total of 34 insufficiency fractures were depicted on imaging studies. MRI demonstrated 33 of the lesions. All the insufficiency fractures were seen as a hypointense lines or fissures on T1- and T2-weighted and STIR MR images. There was a high frequency of insufficiency fractures at the sacrum and iliac bone (16/34, 47%). Overall, 11 chronic-type (no abnormal signal intensity around the fissure) and 22 active-type (abnormal signal intensity around the fissure) insufficiency fractures were detected by MRI. Follow-up MR examinations of 2 subjects showed that abnormal signal intensity had disappeared after appropriate treatment. CONCLUSION: The results of this study showed that the iliac and sacral bones are frequently involved in patients with OM. MRI can determine the clinical activity of the disease, and can monitor the response to treatment of the active type of insufficiency fractures.

Magnetic resonance imaging in osteomalacic insufficiency fractures of the pelvis

International Nuclear Information System (INIS)

Kanberoglu, K.; Kantarci, F.; Cebi, D.; Yilmaz, M.H.; Kurugoglu, S.; Bilici, A.; Koyuncu, H.

2005-01-01

AIMS: To report the magnetic resonance imaging (MRI) findings of osteomalacic insufficiency fractures of the pelvis. MATERIALS AND METHODS: In all, 12 persons presenting with chronic pelvic pain and with a definitive diagnosis of osteomalacia (OM) were enrolled in this study. Radiological work-up included direct radiographs (n=12), computed tomography (n=5), scintigraphy n=12) and MRI (n=12). The location of the insufficiency fractures and corresponding MRI appearances were evaluated. Depending on the presence or absence of signal intensity around the fractures, the lesions were grouped into active and chronic forms. RESULTS: A total of 34 insufficiency fractures were depicted on imaging studies. MRI demonstrated 33 of the lesions. All the insufficiency fractures were seen as a hypointense lines or fissures on T1- and T2-weighted and STIR MR images. There was a high frequency of insufficiency fractures at the sacrum and iliac bone (16/34, 47%). Overall, 11 chronic-type (no abnormal signal intensity around the fissure) and 22 active-type (abnormal signal intensity around the fissure) insufficiency fractures were detected by MRI. Follow-up MR examinations of 2 subjects showed that abnormal signal intensity had disappeared after appropriate treatment. CONCLUSION: The results of this study showed that the iliac and sacral bones are frequently involved in patients with OM. MRI can determine the clinical activity of the disease, and can monitor the response to treatment of the active type of insufficiency fractures

Fatigue in Intensive Care Nurses and Related Factors.

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Çelik, Sevim; Taşdemir, Nurten; Kurt, Aylin; İlgezdi, Ebru; Kubalas, Özge

2017-10-01

Fatigue negatively affects the performance of intensive care nurses. Factors contributing to the fatigue experienced by nurses include lifestyle, psychological status, work organization and sleep problems. To determine the level of fatigue among nurses working in intensive care units and the related factors. This descriptive study was conducted with 102 nurses working in intensive care units in the West Black Sea Region of Turkey. Data were collected between February and May 2014 using a personal information form, the Visual Analogue Scale for Fatigue (VAS-F), the Hospital Anxiety and Depression Scale and the Pittsburg Sleep Quality Index. The intensive care nurses in the study were found to be experiencing fatigue. Significant correlations were observed between scores on the VAS-F Fatigue and anxiety (p=0.01), depression (p=0.002), and sleep quality (pnurses' levels of fatigue. These results can be of benefit in taking measures which may be used to reduce fatigue in nurses, especially the fatigue related to work organization and social life.

3D Simulation of Multiple Simultaneous Hydraulic Fractures with Different Initial Lengths in Rock

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Tang, X.; Rayudu, N. M.; Singh, G.

2017-12-01

Hydraulic fracturing is widely used technique for extracting shale gas. During this process, fractures with various initial lengths are induced in rock mass with hydraulic pressure. Understanding the mechanism of propagation and interaction between these induced hydraulic cracks is critical for optimizing the fracking process. In this work, numerical results are presented for investigating the effect of in-situ parameters and fluid properties on growth and interaction of multi simultaneous hydraulic fractures. A fully coupled 3D fracture simulator, TOUGH- GFEM is used for simulating the effect of different vital parameters, including in-situ stress, initial fracture length, fracture spacing, fluid viscosity and flow rate on induced hydraulic fractures growth. This TOUGH-GFEM simulator is based on 3D finite volume method (FVM) and partition of unity element method (PUM). Displacement correlation method (DCM) is used for calculating multi - mode (Mode I, II, III) stress intensity factors. Maximum principal stress criteria is used for crack propagation. Key words: hydraulic fracturing, TOUGH, partition of unity element method , displacement correlation method, 3D fracturing simulator

Cement Leakage in Percutaneous Vertebral Augmentation for Osteoporotic Vertebral Compression Fractures: Analysis of Risk Factors.

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Xie, Weixing; Jin, Daxiang; Ma, Hui; Ding, Jinyong; Xu, Jixi; Zhang, Shuncong; Liang, De

2016-05-01

The risk factors for cement leakage were retrospectively reviewed in 192 patients who underwent percutaneous vertebral augmentation (PVA). To discuss the factors related to the cement leakage in PVA procedure for the treatment of osteoporotic vertebral compression fractures. PVA is widely applied for the treatment of osteoporotic vertebral fractures. Cement leakage is a major complication of this procedure. The risk factors for cement leakage were controversial. A retrospective review of 192 patients who underwent PVA was conducted. The following data were recorded: age, sex, bone density, number of fractured vertebrae before surgery, number of treated vertebrae, severity of the treated vertebrae, operative approach, volume of injected bone cement, preoperative vertebral compression ratio, preoperative local kyphosis angle, intraosseous clefts, preoperative vertebral cortical bone defect, and ratio and type of cement leakage. To study the correlation between each factor and cement leakage ratio, bivariate regression analysis was employed to perform univariate analysis, whereas multivariate linear regression analysis was employed to perform multivariate analysis. The study included 192 patients (282 treated vertebrae), and cement leakage occurred in 100 vertebrae (35.46%). The vertebrae with preoperative cortical bone defects generally exhibited higher cement leakage ratio, and the leakage is typically type C. Vertebrae with intact cortical bones before the procedure tend to experience type S leakage. Univariate analysis showed that patient age, bone density, number of fractured vertebrae before surgery, and vertebral cortical bone were associated with cement leakage ratio (Pcement leakage are bone density and vertebral cortical bone defect, with standardized partial regression coefficients of -0.085 and 0.144, respectively. High bone density and vertebral cortical bone defect are independent risk factors associated with bone cement leakage.

Association of Insulin-like Growth Factor-1, Bone Mass and Inflammation to Low-energy Distal Radius Fractures and Fracture Healing in Elderly Women Attending Emergency Care.

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Chisalita, Simona I; Chong, Lee Ti; Wajda, Maciej; Adolfsson, Lars; Woisetschläger, Mischa; Spångeus, Anna

2017-11-01

Elderly patients suffer fractures through low-energy mechanisms. The distal radius is the most frequent fracture localization. Insulin-like growth factor-1 (IGF1) plays an important role in the maintenance of bone mass and its levels decline with advancing age and in states of malnutrition. Our aim was to investigate the association of IGF1 levels, bone mass, nutritional status, and inflammation to low-energy distal radius fractures and also study if fracture healing is influenced by IGF1, nutritional status, and inflammation. Postmenopausal women, 55 years or older, with low-energy distal radius fractures occurring due to falling on slippery ground, indoors or outdoors, were recruited in the emergency department (ED) and followed 1 and 5 weeks after the initial trauma with biomarkers for nutritional status and inflammation. Fractures were diagnosed according to standard procedure by physical examination and X-ray. All patients were conservatively treated with plaster casts in the ED. Patients who needed interventions were excluded from our study. Fracture healing was evaluated from radiographs. Fracture healing assessment was made with a five-point scale where the radiological assessment included callus formation, fracture line, and stage of union. Blood samples were taken within 24 h after fracture and analyzed in the routine laboratory. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DXA). Thirty-eight Caucasian women, aged 70.5 ± 8.9 years (mean ± SD) old, were recruited. Nutritional status, as evaluated by albumin (40.3 ± 3.1 g/L), IGF1 (125.3 ± 39.9 μg/L), body mass index (26.9 ± 3.6 kg/m 2 ), arm diameter (28.9 ± 8.9 cm), and arm skinfold (2.5 ± 0.7 cm), was normal. A positive correlation was found between IGF1 at visit 1 and the lowest BMD for hip, spine, or radius (r = 0.39, P = 0.04). High sensitive C-reactive protein (hsCRP) and leukocytes were higher at the fracture event compared to 5 weeks later (P = 0.07 and P

Time dependent fracture growth in intact crystalline rock: new laboratory procedures

International Nuclear Information System (INIS)

Backers, T.; Stephansson, O.

2008-01-01

Short term laboratory tests to determine the strength of rock material are commonly used to assess stability of rock excavations. However, loading the rock below its short term strength may lead to delayed failure due to slow stable fracture growth. This time-dependent phenomenon is called subcritical fracture growth. A fracture mechanics based approach is applied in this study to determine the parameters describing subcritical fracture growth under Mode Ⅰ (tensile) and Mode Ⅱ (in-plane shear) loading in terms of the stress intensity factors of saturated granodiorite from the) Aespoe HRL. A statistical method is applied to data from three-point bending (tension) and Punch-Through Shear with Confining Pressure, PTS/CP, (shear) experiments. One population of each set-up was subjected to rapid loading tests yielding a strength probability distribution. A second population was loaded up to a certain fraction of the statistical percentage for failure and the time-to-failure was determined. From these two populations the subcritical fracture growth parameters were determined successfully. Earlier studies demonstrated subcritical fracture growth under Mode I loading conditions, but this study shows that under a Mode Ⅱ load time-dependent fracture growth exists as well. (authors)

Pelvic fracture in the patient with multiple injuries: factors and lesions associated with mortality.

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Martínez, Fernando; Alegret, Núria; Carol, Federico; Laso, M Jesús; Zancajo, Juanjo; García, Esteban; Ros, Vanesa

2018-01-01

The main objective of this study was to identify demographic, clinical, analytical factors or injuries associated with 30-day mortality in patients with pelvic fractures. Prospective observational study of patients with multiple injuries including pelvic fractures between January 2009 and January 2017. We recorded demographic, clinical, and laboratory data on arrival at the emergency department; type of pelvic fracture; treatments; associated lesions; and 30-day mortality. Univariable and multivariable models were used to analyze the data. A total of 2061 multiple-injury patients were attended; 118 had pelvic fractures. Fifteen of the patients with pelvic fractures (12.7%) died within 30 days. Arterial blood pressure on admission was less than 90 mm Hg in 23.7%, heart rate was over 100 beats per minute in 41.52%, lactic acid level was 20 mg/dL or higher in 67.6%, and base excess of -6 or less was recorded for 26.3%. The mean Injury Severity Score was 20 points. Angiographic embolization was required in 80.6% and preperitoneal packing in 3.4%. The main associated lesions were rib fractures (35.6%), hemo-pneumothorax (31.3%), spinal injuries (35.6%), and head injuries (30%). The 6 independent variables associated with risk of death in multiple-injury patients with pelvic fractures are age, female sex, complex fractures (Tile type C), lactic acid level of 20 mg/dL or more, base excess of -6 or less, and bowel perforation.

Dynamic fracture toughness and evaluation of fracture in a ferritic nodular cast iron for casks

International Nuclear Information System (INIS)

Yasunaka, T.; Nakano, K.

1993-01-01

The effect of loading rate and temperature on fracture toughness of a ferritic nodular cast iron obtained from a thick-walled cylindrical casting has been investigated. Based upon this result, the cast iron is evaluated as a material for casks. (1) In the ductile fracture region, fracture toughness increases with increases in loading rate. (2) Ductile-brittle transition temperature is linearly related to the logarithm of stress intensity rate. (3) In the ductile fracture region, converted plain strain fracture toughness divided by yield stress can be adopted as a material constant which is independent of loading rate and temperature. From the result of a static fracture toughness test, the evaluation of fracture in high loading rate can be made. (4) In the ductile fracture region of the material investigated, the maximum allowable flaw depth exceeded the minimum detectable flaw size by a nondestructive inspection. Ferritic nodular cast iron can be used as a material for casks in the ductile fracture region at least. (J.P.N.)

Stress concentration factor and stress intensity factor on hard metals in connection with the wear characteristics

International Nuclear Information System (INIS)

Dawihl, W.; Altmeyer, G.

1977-01-01

Description of a method to determine stress intensity factors on hard metals by lapping in notches of different diameter. Dependence of the values of the stress intensity factors on the size of the notch base diameter. For tungsten carbide hard metals with 6% Co, determination of a final value of 250 Nmm -3 / 2 . Characterisation of the stress intensity factor governed by the surface roughness which is decisive for the assessment of the wear-resistant behaviour. (orig.) [de

Immediate versus delayed intramedullary nailing for open fractures of the tibial shaft: A multivariate analysis of factors affecting deep infection and fracture healing

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Yokoyama Kazuhiko

2008-01-01

Full Text Available Background: The purpose of this study was to evaluate contributing factors affecting deep infection and fracture healing of open tibia fractures treated with locked intramedullary nailing (IMN by multivariate analysis. Materials and Methods: We examined 99 open tibial fractures (98 patients treated with immediate or delayed locked IMN in static fashion from 1991 to 2002. Multivariate analyses following univariate analyses were derived to determine predictors of deep infection, nonunion, and healing time to union. The following predictive variables of deep infection were selected for analysis: age, sex, Gustilo type, fracture grade by AO type, fracture location, timing or method of IMN, reamed or unreamed nailing, debridement time (≤6 h or> 6 h, method of soft-tissue management, skin closure time (≤1 week or> 1 week, existence of polytrauma (ISS< 18 or ISS≥18, existence of floating knee injury, and existence of superficial/pin site infection. The predictive variables of nonunion selected for analysis was the same as those for deep infection, with the addition of deep infection for exchange of pin site infection. The predictive variables of union time selected for analysis was the same as those for nonunion, excluding of location, debridement time, and existence of floating knee and superficial infection. Results: Six (6.1%; type II Gustilo n=1, type IIIB Gustilo n=5 of the 99 open tibial fractures developed deep infections. Multivariate analysis revealed that timing or method of IMN, debridement time, method of soft-tissue management, and existence of superficial or pin site infection significantly correlated with the occurrence of deep infection ( P < 0.0001. In the immediate nailing group alone, the deep infection rate in type IIIB + IIIC was significantly higher than those in type I + II and IIIA ( P = 0.016. Nonunion occurred in 17 fractures (20.3%, 17/84. Multivariate analysis revealed that Gustilo type, skin closure time, and

The fracture of boron fibre-reinforced 6061 aluminium alloy

Science.gov (United States)

Wright, M. A.; Welch, D.; Jollay, J.

1979-01-01

The fracture of 6061 aluminium alloy reinforced with unidirectional and cross-plied 0/90 deg, 0/90/+ or - 45 deg boron fibres has been investigated. The results have been described in terms of a critical stress intensity, K(Q). Critical stress intensity factors were obtained by substituting the failure stress and the initial crack length into the appropriate expression for K(Q). Values were obtained that depended on the dimensions of the specimens. It was therefore concluded that, for the size of specimen tested, the values of K(Q) did not reflect any basic materials property.

Risk Factors and Clinical Evaluation of Superficial Femoral Artery Stent Fracture: Prote'ge'GPS Stent

International Nuclear Information System (INIS)

Lee, Da Un; Kim, Jae Kyu; Jung, Hye Doo; Huh, Tae Wook; Yim, Nam Yeol; Oh, Hyun jun; Choi, Soo Jin Na; Chang, Nam Kyu

2010-01-01

To evaluate the occurrence of superficial femoral artery stent fractures, the risk factors of stent fracture, and the relationship between fractures and clinical findings. Of the 38 patients who underwent treatment with Prote'ge'GPS stenting due to arterial occlusions on the superficial femoral artery, 17 also underwent a clinical analysis. Forty-three stents were inserted in the 17 superficial femoral arteries, ranging between 15 and 50 cm in length, with a mean treated length of 26.4 cm (15-50 cm). A fracture was evaluated by taking a PA and lateral simple radiography, as well as a follow-up evaluation accompanied with a CT angiography, DSA, and a color Doppler sonography. The examination involved the assessment of the difference between bone fractures due to length, placement, and frequency. Fractures occurred in 13 of 43 stents (30.2%). A total of 10 (71.4%) occurred in the upper third, compared to 4 (28.6%) in the lower third of the superficial femoral artery. In addition, 10 stents (71.4%) had a single strut fracture, whereas 4 (28.6%) had multiple strut fractures. A stent fracture occurred more frequently when the stents and lesions were longer (p=0.021, 0.012) and the stents were inserted near the joint. However, there was no significant relationship between stent numbers and the fractures (p=0.126). When the stents were inserted along the popliteal artery, a stent fracture occurred more frequently in the lower third of the artery. The stent fractures did not significantly influence the patency rate of the stented artery (p=0.44) Prote'ge'GPS stents in the superficial femoral artery revealed a considerable number of fractures and the fracture frequency showed a significant relationship with the length of stents and lesions. The closer stent insertion was to the joints, the more frequently fractures occurred. There were no evident significant relationships between the presence of stent fractures and the patency of the stented arteries

Prevalence of and risk factors for osteoporosis and fracture among a male HIV-infected population in the UK.

Science.gov (United States)

Short, Charlotte-Eve S; Shaw, Simon G; Fisher, Martin J; Walker-Bone, Karen; Gilleece, Yvonne C

2014-02-01

Rates of osteoporosis and fracture may be increased in HIV but there are few UK data. Our aim was to examine the prevalence of and risk factors for osteoporosis and fractures among a homogeneous cohort of well-characterized HIV-infected men. In total, 168 men were recruited, median age 45 years, 37 combination antiretroviral therapy (cART) naïve, 46 with exposed longer term (median >10 years). All participants provided information on bone health and underwent DEXA scanning. Osteopenia was found in 58% of subjects and osteoporosis in 12%; 14% reported fractures since HIV diagnosis. Number of fractures since HIV diagnosis was significantly increased among those with osteoporosis (OR 3.5, 95% CI 1.2-10.4, p = 0.018). Duration of infection greater than 13 years was significantly associated with osteoporosis. Duration of cART was associated in univariate but not multivariate analyses. Strategies to prevent osteoporosis and fractures in HIV will require attention to viral and lifestyle factors and not just cART.

The factors influencing the decision making of operative treatment for proximal humeral fractures.

Science.gov (United States)

Hageman, Michiel G J S; Jayakumar, Prakash; King, John D; Guitton, Thierry G; Doornberg, Job N; Ring, David

2015-01-01

The factors influencing the decision making of operative treatment for fractures of the proximal humerus are debated. We hypothesized that there is no difference in treatment recommendations between surgeons shown radiographs alone and those shown radiographs and patient information. Secondarily, we addressed (1) factors associated with a recommendation for operative treatment, (2) factors associated with recommendation for arthroplasty, (3) concordance with the recommendations of the treating surgeons, and (4) factors affecting the inter-rater reliability of treatment recommendations. A total of 238 surgeons of the Science of Variation Group rated 40 radiographs of patients with proximal humerus fractures. Participants were randomized to receive information about the patient and mechanism of injury. The response variables included the choice of treatment (operative vs nonoperative) and the percentage of matches with the actual treatment. Participants who received patient information recommended operative treatment less than those who received no information. The patient information that had the greatest influence on treatment recommendations included age (55%) and fracture mechanism (32%). The only other factor associated with a recommendation for operative treatment was region of practice. There was no significant difference between participants who were and were not provided with information regarding agreement with the actual treatment (operative vs nonoperative) provided by the treating surgeon. Patient information-older age in particular-is associated with a higher likelihood of recommending nonoperative treatment than radiographs alone. Clinical information did not improve agreement of the Science of Variation Group with the actual treatment or the generally poor interobserver agreement on treatment recommendations. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Elastic-plastic fracture mechanics study of thermal shock cracking

International Nuclear Information System (INIS)

Hirano, K.; Kobayashi, H.; Nakazawa, H.

1980-01-01

This paper describes thermal shock experiments conducted on a nuclear pressure vessel steel (A533 Grade B Class 1), an AISI304 steel and a tool steel (JIS SKD62) using both a new thermal shock test facility and method. Analysis of their quasi-static thermal stress intensity factors is performed on the basis of linear-elastic fracture mechanics; and a thermal shock fracture toughness value, Ksub(tsc) is evaluated. Then elastic-plastic fracture toughness tests are carried out in the same high temperature range of the thermal shock experiment, and a relation between the stretched zone width, SZW, formed as a result of the fatigue precrack tip plastic blunting and the J-integral is clarified. An elastic-plastic thermal shock fracture toughness value, Jsub(tsc), is evaluated from a critical value of the stretched zone width, SZWsub(tsc), at the initiation of the thermal shock cracking by using the relation between SZW and J. The Jsub(tsc) value is compared with an elastic-plastic fracture toughness value, Jsub(Ic), and the difference between these Jsub(tsc) and Jsub(Ic) values is discussed on the basis of fractography. (author)

Statistical geological discrete fracture network model. Forsmark modelling stage 2.2

Energy Technology Data Exchange (ETDEWEB)

Fox, Aaron; La Pointe, Paul [Golder Associates Inc (United States); Simeonov, Assen [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Hermanson, Jan; Oehman, Johan [Golder Associates AB, Stockholm (Sweden)

2007-11-15

The Swedish Nuclear Fuel and Waste Management Company (SKB) is performing site characterization at two different locations, Forsmark and Laxemar, in order to locate a site for a final geologic repository for spent nuclear fuel. The program is built upon the development of Site Descriptive Models (SDMs) at specific timed data freezes. Each SDM is formed from discipline-specific reports from across the scientific spectrum. This report describes the methods, analyses, and conclusions of the geological modeling team with respect to a geological and statistical model of fractures and minor deformation zones (henceforth referred to as the geological DFN), version 2.2, at the Forsmark site. The geological DFN builds upon the work of other geological modelers, including the deformation zone (DZ), rock domain (RD), and fracture domain (FD) models. The geological DFN is a statistical model for stochastically simulating rock fractures and minor deformation zones as a scale of less than 1,000 m (the lower cut-off of the DZ models). The geological DFN is valid within four specific fracture domains inside the local model region, and encompassing the candidate volume at Forsmark: FFM01, FFM02, FFM03, and FFM06. The models are build using data from detailed surface outcrop maps and the cored borehole record at Forsmark. The conceptual model for the Forsmark 2.2 geological revolves around the concept of orientation sets; for each fracture domain, other model parameters such as size and intensity are tied to the orientation sets. Two classes of orientation sets were described; Global sets, which are encountered everywhere in the model region, and Local sets, which represent highly localized stress environments. Orientation sets were described in terms of their general cardinal direction (NE, NW, etc). Two alternatives are presented for fracture size modeling: - the tectonic continuum approach (TCM, TCMF) described by coupled size-intensity scaling following power law distributions

Statistical geological discrete fracture network model. Forsmark modelling stage 2.2

International Nuclear Information System (INIS)

Fox, Aaron; La Pointe, Paul; Simeonov, Assen; Hermanson, Jan; Oehman, Johan

2007-11-01

The Swedish Nuclear Fuel and Waste Management Company (SKB) is performing site characterization at two different locations, Forsmark and Laxemar, in order to locate a site for a final geologic repository for spent nuclear fuel. The program is built upon the development of Site Descriptive Models (SDMs) at specific timed data freezes. Each SDM is formed from discipline-specific reports from across the scientific spectrum. This report describes the methods, analyses, and conclusions of the geological modeling team with respect to a geological and statistical model of fractures and minor deformation zones (henceforth referred to as the geological DFN), version 2.2, at the Forsmark site. The geological DFN builds upon the work of other geological modelers, including the deformation zone (DZ), rock domain (RD), and fracture domain (FD) models. The geological DFN is a statistical model for stochastically simulating rock fractures and minor deformation zones as a scale of less than 1,000 m (the lower cut-off of the DZ models). The geological DFN is valid within four specific fracture domains inside the local model region, and encompassing the candidate volume at Forsmark: FFM01, FFM02, FFM03, and FFM06. The models are build using data from detailed surface outcrop maps and the cored borehole record at Forsmark. The conceptual model for the Forsmark 2.2 geological revolves around the concept of orientation sets; for each fracture domain, other model parameters such as size and intensity are tied to the orientation sets. Two classes of orientation sets were described; Global sets, which are encountered everywhere in the model region, and Local sets, which represent highly localized stress environments. Orientation sets were described in terms of their general cardinal direction (NE, NW, etc). Two alternatives are presented for fracture size modeling: - the tectonic continuum approach (TCM, TCMF) described by coupled size-intensity scaling following power law distributions

Factores de riesgo de fracturas por fragilidad en una cohorte de mujeres españolas Risk factors for fragility fractures in a cohort of Spanish women

Directory of Open Access Journals (Sweden)

Cristian Tebé

2011-12-01

Full Text Available Introducción: Las fracturas por fragilidad constituyen un problema de salud pública. El objetivo fue analizar la asociación de los principales factores de riesgo de osteoporosis con la fracturas por fragilidad en una cohorte de mujeres con indicación de densitometría ósea. Métodos: Cohorte retrospectiva con seguimiento hasta una fractura por fragilidad, de una población de mujeres de 40 a 90 años de edad con una primera visita para realizarse una densitometría entre enero de 1992 y febrero de 2008. Se calcularon la tasa de incidencia de fracturas por 1000 mujeres-año de seguimiento y la hazard ratio (HR de fractura mediante un modelo de regresión de Cox. Resultados: Se estudiaron 49.735 mujeres con una edad media de 57,8 años (desviación estándar: 8,5. De ellas, 3631 mujeres (7,1% declararon al menos una fractura por fragilidad en las visitas posteriores a la basal. Los factores de riesgo con una mayor HR ajustada fueron la edad >75 años respecto a Introduction: Fragility fractures are an important public health issue. The aim of this study was to analyze the association of the main osteoporotic risk factors related to fragility fracture in a cohort of women with an indication of bone densitometry (BD. Methods: A retrospective cohort was followed-up until a fragile fracture occurred, in a population of women aged 40 to 90 years with a first visit for BD between January 1992 and February 2008. We calculated the incidence rate of fracture per 1000 women-years of follow-up, and the hazard ratio (HR of fragile fracture using a Cox regression model. Results: A total of 49,735 women were studied. The average age of participants was 57.8 years (SD: 8.5. Of these, 3631 women (7.1% reported a new fragility fracture in post-baseline visits. Risk factors with higher adjusted HR were age > 75 years compared with age < 55 years (HR: 3.8; 95% CI: 3.3-4.4 and having a BC result evaluated as osteoporosis compared to normal (HR: 2.0; 95% CI: 1

Rib fractures after reirradiation plus hyperthermia for recurrent breast cancer: Predictive factors

NARCIS (Netherlands)

Oldenborg, Sabine; Valk, Christel; van Os, Rob; Oei, Bing; Venselaar, Jack; Vörding, Paul Zum Vörde Sive; van Randen, Adriënne; Crezee, Hans; van Tienhoven, Geertjan; Rasch, Coen

2016-01-01

Combining reirradiation (reRT) and hyperthermia (HT) has shown high therapeutic value for patients with locoregional recurrent breast cancer (LR). However, additional toxicity of reirradiation (e.g., rib fractures) may occur. The aim of this study is to determine the impact of potential risk factors

Risk factors and epidemiological profile of hip fractures in Indian population: A case-control study

Directory of Open Access Journals (Sweden)

Kaustubh Ahuja

2017-09-01

Conclusions: Hip fractures in the elderly population are on a rising trend especially in the Indian subcontinent due to a number of factors both hereditary and acquired. Simple measures like routine usage of bedside railing, wall-side railings at an appropriate height, high friction tiles inside rooms and washrooms, and adequate lighting indoors can play a significant role in reducing falls and hip fractures among the elderly.

Factors that influence exercise activity among women post hip fracture participating in the Exercise Plus Program

Directory of Open Access Journals (Sweden)

Barbara Resnick

2007-10-01

Full Text Available Barbara Resnick1, Denise Orwig2, Christopher D’Adamo2, Janet Yu-Yahiro3, William Hawkes2, Michelle Shardell2, Justine Golden2, Sheryl Zimmerman4, Jay Magaziner21University of Maryland School of Nursing, 655 West Lombard Street, Baltimore, MD,21201, USA; 2University of Maryland School of Medicine, Howard Hall, Redwood Street, Baltimore MD 21201, USA; 3Department of Orthopaedic Surgery, Union Memorial Hospital, Baltimore, USA; 4University of North Carolina Chapel Hill, 301 Pittsboro St., CB#3550, Chapel Hill, NC 27599-3550, USAAbstract: Using a social ecological model, this paper describes selected intra- and interpersonal factors that influence exercise behavior in women post hip fracture who participated in the Exercise Plus Program. Model testing of factors that influence exercise behavior at 2, 6 and 12 months post hip fracture was done. The full model hypothesized that demographic variables; cognitive, affective, physical and functional status; pain; fear of falling; social support for exercise, and exposure to the Exercise Plus Program would influence self-efficacy, outcome expectations, and stage of change both directly and indirectly influencing total time spent exercising. Two hundred and nine female hip fracture patients (age 81.0 ± 6.9, the majority of whom were Caucasian (97%, participated in this study. The three predictive models tested across the 12 month recovery trajectory suggest that somewhat different factors may influence exercise over the recovery period and the models explained 8 to 21% of the variance in time spent exercising. To optimize exercise activity post hip fracture, older adults should be helped to realistically assess their self-efficacy and outcome expectations related to exercise, health care providers and friends/peers should be encouraged to reinforce the positive benefits of exercise post hip fracture, and fear of falling should be addressed throughout the entire hip fracture recovery trajectory

Factors Associated With Psycho-Cognitive Functions in Patients With Persistent Pain After Surgery for Femoral Neck Fracture.

Science.gov (United States)

Kitayama, Atsushi; Hida, Mitsumasa; Takami, Hidenobu; Hirata, Naoki; Deguchi, Yuko; Miyaguchi, Kazuya; Nakazono, Masako; Nakagawa, Rie; Fukumoto, Noriyuki; Hamaoka, Katsumi

2017-09-01

The aim of the study was to address issues arising from fracture of the femoral neck in elderly individuals, the prevalence of which continues to increase in Japan. The prevalence is increasing in Japan and there have been many reports on physical functions such as prevention of a fall. However, there have been a few studies that focus on psycho-cognitive functions. We must examine factors in patients with fractured femur necks to develop methods to assist affected patients. The current study aimed to examine factors associated with psycho-cognitive functions after surgery for fractured femoral neck in the Japanese elderly. In this study, we examined the relationships among sex, age, fracture site, operative procedure, body mass index, lifestyle, psycho-cognitive functions, and types of pain in 142 patients, performed multiple regression analysis using the mini-mental state examination (MMSE) and the Montgomery-Asberg depression rating scale (MADRS) scores as dependent variables, and created MMSE and MADRS models. Analysis of MMSE and MADRS models identified night pain and the number of family members as factors that affected mental function in a population with persistent pain for 1 week after surgery for fractured femoral neck. In addition, the number of family members was identified in multiple regression analysis models as a factor associated with psycho-cognitive functions. Pain, and night pain in particular, affect psycho-cognitive functions. We speculated that emotional changes were associated with number of family members. Patients living with family members maintained psycho-cognitive functions better than did those living alone, even when they experienced pain in their daily lives.

Calcaneal Fractures in Non-Racing Dogs and Cats: Complications, Outcome, and Associated Risk Factors.

Science.gov (United States)

Perry, Karen L; Adams, Robert J; Woods, Samantha; Bruce, Mieghan

2017-01-01

To estimate the prevalence of complications and describe the outcome associated with calcaneal fractures in non-racing dogs and in cats. Retrospective multicenter clinical cohort study. Medical records of client-owned dogs and cats (2004-2013). Medical records were searched and 50 animals with calcaneal fractures were included for analysis. Complications were recorded and an outcome score applied to each fracture. Associations between putative risk factors and both major complications, and final outcome scores were explored. Complications occurred in 27/50 fractures (61%) including 23 major and 4 minor complications. At final follow-up, 4 animals (10%) were sound, 27 (64%) had either intermittent or consistent mild weight-bearing lameness, 7 (17%) had moderate weight-bearing lameness, and 1 (2%) had severe weight-bearing lameness. Fractures managed using plates and screws had a lower risk of complications than fractures managed using pin and tension band wire, lag or positional screws or a combination of these techniques (Relative risk 0.16, 95% CI 0.02-1.02, P=.052). Non-sighthounds had reduced odds of a poorer outcome score than sighthounds (Odds ratio 0.11, 95% CI 0.02-0.50, P=.005) and fractures with major complications had 13 times the odds of a poorer outcome score (Odds ratio 13.4, 95% CI 3.6-59.5, Pdogs and in cats, and a poorer outcome score was more likely in animals with complications. A more guarded prognosis should be given to owners of non-racing dogs or cats with calcaneal fractures than previously applied to racing Greyhounds with calcaneal fractures. © 2016 The American College of Veterinary Surgeons.

Fatigue stress fractures of the sacrum: diagnosis with MR imaging

International Nuclear Information System (INIS)

Ahovuo, J.A.; Vusuri, T.

2004-01-01

The aim of this study was to describe the MRI findings and clinical observations in a fatigue stress fracture of the sacrum. In this retrospective study, 380 conscripts (53 women, 327 men; age range 18-29 years, mean age 20.7 years) who suffered from stress-related hip pain were studied with MRI of the pelvis. The findings of MRI were evaluated with regard to stress fracture of the sacrum. Thirty-one (8%) patients had MRI changes in signal intensity of the cranial part of the sacrum, extending to the first and second sacral foramina. The MRI changes in signal intensity were intermediate on T1-weighted images, and high on short tau inversion recovery or T2-weighted fat-suppressed images. A linear signal void fracture line was also seen. Multiple stress injuries to the pelvic bones were also seen in 7 of 31 (23%) patients. Five patients (16%) had bilateral sacral stress fracture. Fatigue sacral stress fractures appeared more commonly in women than in men (p<0.001). During recovery time 20 of the 31 patients underwent control MRI, and fatty marrow conversion was seen in 8 (40%) cases as high signal intensity on T1-weighted images, which disappeared 5-6 months after the onset of symptoms. Fatigue sacral stress fractures are associated with stress-related hip pain. These fractures were more common in women than in men. Other stress injuries of the pelvis may be seen simultaneously with sacral stress fractures. Signal intensity of the sacrum was normal after 5-6 months

Sacral Stress Fracture in an Amateur Badminton Player

Directory of Open Access Journals (Sweden)

Yusuke Yuasa

2017-01-01

Full Text Available Sacral stress fractures are rare among athletes but have been reported most frequently in long distance runners. We report herein the first case of a sacral stress fracture in an amateur badminton player. A 16-year-old, left-handed adolescent girl, who had just started to play badminton 3 months previously, complained of acute left buttock pain when she received a shuttlecock. Magnetic resonance imaging revealed a linear lesion of the left sacrum with low signal intensity on T1- and high signal intensity on T2-weighted images, which was consistent with a stress fracture. Conservative treatment with rest relieved her symptoms. Her fracture was considered to have occurred due to repetition of an exercise that caused excessive vertical power.

Environmental controls on micro fracture processes in shelf ice

Science.gov (United States)

Sammonds, Peter

2013-04-01

The recent retreat and collapse of the ice shelves on the Antarctic Peninsula has been associated with regional atmospheric warming, oceanic warming, increased summer melt and shelf flexure. Although the cause of collapse is a matter of active discussion, the process is that of fracture of a creep-brittle material, close to its melting point. The environmental controls on how fracturing initiates, at a micro-scale, strongly determine the macroscopic disintegration of ice shelves. In particular the shelf temperature profile controls the plasticity of the ice shelf; the densification of shelf ice due to melting and re-freezing affects the crack tip stress intensity; the accretion of marine ice at the bottom of the shelf imposes a thermal/mechanical discontinuity; saline environments control crack tip stress corrosion; cyclic loading promotes sub-critical crack propagation. These strong environmental controls on shelf ice fracture means that assessing shelf stability is a non-deterministic problem. How these factors may be parameterized in ice shelf models, through the use of fracture mechanisms maps, is discussed. The findings are discussed in relation to the stability of Larsen C.

Serial MRI findings of osteoporotic vertebral fractures in the thoracic and lumbar spine

Energy Technology Data Exchange (ETDEWEB)

Hamada, Yoshitaka; Henmi, Tatsuhiko; Sakamoto, Rintaro; Hiasa, Masahiko [Health Insurance Naruto Hospital, Tokushima (Japan)

1998-12-01

The prognosis of osteoporotic vertebral fractures in the thoracic and lumbar spine was studied by serial MRI findings. This study covered 80 vertebrae in 69 patients treated conservatively and followed-up for more than six months (23 males and 46 females, average age 70 yrs). Group A, characterized by poor diagnostic imaging, consisted of patients who had both severely collapsed vertebra which was progressive in the lateral roentgenogram and delayed improvement in MRI signal intensities. Group B, consisting of poor clinical prognosis, comprised patients with persistent back pain. The predictive factors for Group A were found to be T{sub 1}-low finding over the entire vertebra within one month after injury and fractures of Th{sub 12} or L{sub 1} vertebra. Areas of T{sub 1}-low and T{sub 2}-low intensity adjacent to the vertebral disc presented no improvement in signal intensity and often caused persistent back pain. (author)

Bone and fall-related fracture risks in women and men with a recent clinical fracture.

Science.gov (United States)

van Helden, Svenhjalmar; van Geel, Antonia C M; Geusens, Piet P; Kessels, Alfons; Nieuwenhuijzen Kruseman, Arie C; Brink, Peter R G

2008-02-01

Worldwide fracture rates are increasing as a result of the aging population, and prevention, both primary and secondary, is an important public health goal. Therefore, we systematically analyzed risk factors in subjects with a recent clinical fracture. All men and women over fifty years of age who had been treated in the emergency department of, or hospitalized at, our institution because of a recent fracture during a one-year period were offered the opportunity to undergo an evidence-based bone and fall-related risk-factor assessment and bone densitometry. The women included in this study were also compared with a group of postmenopausal women without a fracture history who had been included in another cohort study. Of the 940 consecutive patients, 797 (85%) were eligible for this study and 568 (60%) agreed to participate. The prevalence of fall-related risk factors (75% [95% confidence interval = 71% to 78%]; n = 425) and the prevalence of bone-related risk factors (53% [95% confidence interval = 49% to 57%]; n = 299) at the time of fracture were higher than the prevalence of osteoporosis (35% [95% confidence interval = 31% to 39%]; n = 201) as defined by a dual x-ray absorptiometry T score of fall and bone-related risk factors were present irrespective of the fracture location, patient age, or gender. An overlap between bone and fall-related risk factors was found in 50% of the patients. After adjusting for age, weight, and height, we found that women with a fracture more frequently had a diagnosis of osteoporosis (odds ratio = 2.9; 95% confidence interval = 2.0 to 4.1) and had a more extensive history of falls (odds ratio = 4.0; 95% confidence interval = 2.7 to 5.9) than did the postmenopausal women without a fracture history. Men and women over fifty years of age who had recently sustained a clinical fracture had, at the time of that fracture, bone and fall-related risk factors that were greater than the risk predicted by the presence of osteoporosis. Risk

Different aspects of visual impairment as risk factors for falls and fractures in older men and women

NARCIS (Netherlands)

de Boer, Michiel R; Pluijm, Saskia M F; Lips, Paul; Moll, Annette C; Völker-Dieben, Hennie J; Deeg, Dorly J H; van Rens, Ger H M B

UNLABELLED: Visual impairment has been implicated as a risk factor for falling and fractures, but results of previous studies have been inconsistent. The relationship between several aspects of vision and falling/fractures were examined in a prospective cohort study in 1,509 older men and women. The

The stress and stress intensity factors computation by BEM and FEM combination for nozzle junction under pressure and thermal loads

International Nuclear Information System (INIS)

Du, Q.; Cen, Z.; Zhu, H.

1989-01-01

This paper reports linear elastic fracture analysis based upon the stress intensity factor evaluation successfully applied to safety assessments of cracked structures. The nozzle junction are usually subjected to high pressure and thermal loads simultaneously. In validity of linear elastic fracture analysis, K can be decomposed into K P (caused by mechanic loads) and K τ (caused by thermal loads). Under thermal transient loading, explicit analysis (say by the FEM or BEM) of K tracing an entire history respectively for a range of crack depth may be much more time consuming. The techniques of weight function provide efficient means for transforming the problem into the stress computation of the uncracked structure and generation of influence function (for the given structure and size of crack). In this paper, a combination of BE-FEM has been used for the analysis of the cracked nozzle structure by techniques of weight function. The influence functions are obtained by coupled BE-FEM and the uncracked structure stress are computed by finite element methods

Risk factors associated with incident clinical vertebral and nonvertebral fractures in postmenopausal women: the Canadian Multicentre Osteoporosis Study (CaMos).

Science.gov (United States)

Papaioannou, Alexandra; Joseph, Lawrence; Ioannidis, George; Berger, Claudie; Anastassiades, Tassos; Brown, Jacques P; Hanley, David A; Hopman, Wilma; Josse, Robert G; Kirkland, Susan; Murray, Timothy M; Olszynski, Wojciech P; Pickard, Laura; Prior, Jerilynn C; Siminoski, Kerry; Adachi, Jonathan D

2005-05-01

Utilizing data from the Canadian Multicentre Osteoporosis Study (CaMos), we examined the association between potential risk factors and incident vertebral and nonvertebral fractures. A total of 5,143 postmenopausal women were enrolled. Information collected during the study included data from the CaMos baseline and annually mailed fracture questionnaires, the Short Form 36 (SF-36), the Health Utilities Index, and physical measurements. Participants were followed for 3 years. Postmenopausal women were classified into four groups according to their incident fracture status since baseline: those without a new fracture; those with a new clinically recognized vertebral fracture; those with an incident nonvertebral fracture at the wrist, hip, humerus, pelvis, or ribs (main nonvertebral fracture group); and those with any new nonvertebral fracture (any-nonvertebral-fracture group). We performed multivariate Cox proportional hazard analysis using all possible risk factors to determine the association between risk factors and the time to the first minimal trauma fracture. Best predictive models were also determined using variables that were included in the full models. The Bayesian information criterion was used for model selection. For all analyses, relative risks and associated 95% confidence intervals were calculated. During the follow-up period, 34, 163, and 280 women developed a vertebral, a main nonvertebral, or any nonvertebral fracture, respectively. The best predictive models indicated that a five point lower quality of life as measured by the SF-36 physical component summary score was associated with relative risks of 1.21 (95% CI, 1.02 to 1.44), 1.17 (95% CI, 1.07 to 1.28), and 1.19 (95% CI, 1.11 to 1.27) for incident vertebral, main nonvertebral, and all nonvertebral fractures, respectively. In addition, for a one standard deviation (SD=0.12) lower femoral neck BMD, the relative risks for incident vertebral, main nonvertebral, and any nonvertebral fractures

Fracture analysis of a transversely isotropic high temperature superconductor strip based on real fundamental solutions

Science.gov (United States)

Gao, Zhiwen; Zhou, Youhe

2015-04-01

Real fundamental solution for fracture problem of transversely isotropic high temperature superconductor (HTS) strip is obtained. The superconductor E-J constitutive law is characterized by the Bean model where the critical current density is independent of the flux density. Fracture analysis is performed by the methods of singular integral equations which are solved numerically by Gauss-Lobatto-Chybeshev (GSL) collocation method. To guarantee a satisfactory accuracy, the convergence behavior of the kernel function is investigated. Numerical results of fracture parameters are obtained and the effects of the geometric characteristics, applied magnetic field and critical current density on the stress intensity factors (SIF) are discussed.

Intensely irradiated steel components: Plastic and fracture properties, and a new concept of structural design criteria for assuring the structural integrity

International Nuclear Information System (INIS)

Suzuki, Kazuhiko; Jitsukawa, Shiro; Okubo, Nariaki; Takada, Fumiki

2010-01-01

In order to develop a systematic and reasonable concept assuring the structural integrity of components under intense neutron irradiation, two basic tensile properties, true stress-true strain (TS-TS) curves and fracture strain, were investigated on an austenitic stainless steel and martensitic steel. Application of Swift equation is confirmed to a large plastic strain range of TS-TS curves. Fracture strain ε f data were well correlated as ε f + ε 0 = const. where ε 0 is the pre-strain representing the irradiation hardening. Based on those formulations and available experimental information, several critical issues to be dealt with in developing the concept were identified possible reduction in ductility, significant change in mechanical properties, remarkable cyclic softening and other unique cyclic properties observed during a high-cycle fatigue testing, and the redundancy of the plastic collapse concept to bending. Existing structural codes are all based on the assumption that there will be no significant changes in mechanical properties during operation, and of high ductility. Therefore, a new concept for assuring structural integrity is required for application not only to components with high ductility but also components with reduced ductility. First, potential failure modes were identified, and a new and systematic concept was proposed for preventing these modes of failure, introducing a new concept of categorizing the loadings by stability of deformation process to fracture (as type F and M loadings). Based on the basic concept, a detailed concept of how to protect against ductile fracture was given, and loading type-dependent limiting parameters were set. Finally, application of the detailed concept was presented, especially on determination of loading type (in numerical approach, the formulation of TS-TS curves and fracture strain derived above are needed), and on how to determine the limiting parameters as allowable limits. Experiments were done to

Intensely irradiated steel components: Plastic and fracture properties, and a new concept of structural design criteria for assuring the structural integrity

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Kazuhiko, E-mail: suzuki.kazuhiko@jaea.go.j [Japan Atomic Energy Agency, Nuclear Science and Engineering Directorate, 2-4 Shirane, Shirakata, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Jitsukawa, Shiro; Okubo, Nariaki [Japan Atomic Energy Agency, Nuclear Science and Engineering Directorate, 2-4 Shirane, Shirakata, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Takada, Fumiki [Japan Atomic Energy Agency, Department of JMTR Operation, Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki-ken 311-1393 (Japan)

2010-06-15

In order to develop a systematic and reasonable concept assuring the structural integrity of components under intense neutron irradiation, two basic tensile properties, true stress-true strain (TS-TS) curves and fracture strain, were investigated on an austenitic stainless steel and martensitic steel. Application of Swift equation is confirmed to a large plastic strain range of TS-TS curves. Fracture strain epsilon{sub f} data were well correlated as epsilon{sub f} + epsilon{sub 0} = const. where epsilon{sub 0} is the pre-strain representing the irradiation hardening. Based on those formulations and available experimental information, several critical issues to be dealt with in developing the concept were identified possible reduction in ductility, significant change in mechanical properties, remarkable cyclic softening and other unique cyclic properties observed during a high-cycle fatigue testing, and the redundancy of the plastic collapse concept to bending. Existing structural codes are all based on the assumption that there will be no significant changes in mechanical properties during operation, and of high ductility. Therefore, a new concept for assuring structural integrity is required for application not only to components with high ductility but also components with reduced ductility. First, potential failure modes were identified, and a new and systematic concept was proposed for preventing these modes of failure, introducing a new concept of categorizing the loadings by stability of deformation process to fracture (as type F and M loadings). Based on the basic concept, a detailed concept of how to protect against ductile fracture was given, and loading type-dependent limiting parameters were set. Finally, application of the detailed concept was presented, especially on determination of loading type (in numerical approach, the formulation of TS-TS curves and fracture strain derived above are needed), and on how to determine the limiting parameters as

The loss of activating transcription factor 4 (ATF4) reduces bone toughness and fracture toughness.

Science.gov (United States)

Makowski, Alexander J; Uppuganti, Sasidhar; Wadeer, Sandra A; Whitehead, Jack M; Rowland, Barbara J; Granke, Mathilde; Mahadevan-Jansen, Anita; Yang, Xiangli; Nyman, Jeffry S

2014-05-01

Even though age-related changes to bone tissue affecting fracture risk are well characterized, only a few matrix-related factors have been identified as important to maintaining fracture resistance. As a gene critical to osteoblast differentiation, activating transcription factor 4 (ATF4) is possibly one of these important factors. To test the hypothesis that the loss of ATF4 affects the fracture resistance of bone beyond bone mass and structure, we harvested bones from Atf4+/+ and Atf4-/- littermates at 8 and 20 weeks of age (n≥9 per group) for bone assessment across several length scales. From whole bone mechanical tests in bending, femurs from Atf4-/- mice were found to be brittle with reduced toughness and fracture toughness compared to femurs from Atf4+/+ mice. However, there were no differences in material strength and in tissue hardness, as determined by nanoindentation, between the genotypes, irrespective of age. Tissue mineral density of the cortex at the point of loading as determined by micro-computed tomography was also not significantly different. However, by analyzing local composition by Raman Spectroscopy (RS), bone tissue of Atf4-/- mice was found to have higher mineral to collagen ratio compared to wild-type tissue, primarily at 20 weeks of age. From RS analysis of intact femurs at 2 orthogonal orientations relative to the polarization axis of the laser, we also found that the organizational-sensitive peak ratio, ν1Phosphate per Amide I, changed to a greater extent upon bone rotation for Atf4-deficient tissue, implying bone matrix organization may contribute to the brittleness phenotype. Target genes of ATF4 activity are not only important to osteoblast differentiation but also in maintaining bone toughness and fracture toughness. Published by Elsevier Inc.

The Loss of Activating Transcription Factor 4 (ATF4) Reduces Bone Toughness and Fracture Toughness

Science.gov (United States)

Makowski, Alexander J.; Uppuganti, Sasidhar; Waader, Sandra A.; Whitehead, Jack M.; Rowland, Barbara J.; Granke, Mathilde; Mahadevan-Jansen, Anita; Yang, Xiangli; Nyman, Jeffry S.

2014-01-01

Even though age-related changes to bone tissue affecting fracture risk are well characterized, only a few matrix-related factors have been identified as important to maintaining fracture resistance. As a gene critical to osteoblast differentiation, activating transcription factor 4 (ATF4) is possibly one of the seimportant factors. To test the hypothesis that the loss of ATF4 affects the fracture resistance of bone beyond bone mass and structure, we harvested bones from Atf4+/+ and Atf4−/− littermates at 8 and 20 weeks of age (n≥9 per group) for bone assessment across several length scales. From whole bone mechanical tests in bending, femurs from Atf4−/− mice were found to be brittle with reduced toughness and fracture toughness compared to femurs from Atf4+/+ mice. However, there were no differences in material strength and in tissue hardness, as determined by nanoindentation, between the genotypes, irrespective age. Tissue mineral density of the cortex at the point of loading as determined by micro-computed tomography was also not significantly different. However, by analyzing local composition by Raman Spectroscopy (RS), bone tissue of Atf4−/− mice was found to have higher mineral to collagen ratio compared to wild-type tissue, primarily at 20 weeks of age. From RS analysis of intact femurs at 2 orthogonal orientations relative to the polarization axis of the laser, we also found that the organizational-sensitive peak ratio, ν1 Phosphate per Amide I, changed to a greater extent upon bone rotation for Atf4-deficient tissue, implying bone matrix organization may contribute to the brittleness phenotype. Target genes of ATF4 activity are not only important to osteoblast differentiation but also maintaining bone toughness and fracture toughness. PMID:24509412

Fracture Capabilities in Grizzly with the extended Finite Element Method (X-FEM)

Energy Technology Data Exchange (ETDEWEB)

Dolbow, John [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Ziyu [Idaho National Lab. (INL), Idaho Falls, ID (United States); Spencer, Benjamin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jiang, Wen [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-09-01

Efforts are underway to develop fracture mechanics capabilities in the Grizzly code to enable it to be used to perform deterministic fracture assessments of degraded reactor pressure vessels (RPVs). A capability was previously developed to calculate three-dimensional interaction- integrals to extract mixed-mode stress-intensity factors. This capability requires the use of a finite element mesh that conforms to the crack geometry. The eXtended Finite Element Method (X-FEM) provides a means to represent a crack geometry without explicitly fitting the finite element mesh to it. This is effected by enhancing the element kinematics to represent jump discontinuities at arbitrary locations inside of the element, as well as the incorporation of asymptotic near-tip fields to better capture crack singularities. In this work, use of only the discontinuous enrichment functions was examined to see how accurate stress intensity factors could still be calculated. This report documents the following work to enhance Grizzly’s engineering fracture capabilities by introducing arbitrary jump discontinuities for prescribed crack geometries; X-FEM Mesh Cutting in 3D: to enhance the kinematics of elements that are intersected by arbitrary crack geometries, a mesh cutting algorithm was implemented in Grizzly. The algorithm introduces new virtual nodes and creates partial elements, and then creates a new mesh connectivity; Interaction Integral Modifications: the existing code for evaluating the interaction integral in Grizzly was based on the assumption of a mesh that was fitted to the crack geometry. Modifications were made to allow for the possibility of a crack front that passes arbitrarily through the mesh; and Benchmarking for 3D Fracture: the new capabilities were benchmarked against mixed-mode three-dimensional fracture problems with known analytical solutions.

A fracture mechanics assessment of surface cracks existing in protective layers of multi-layer composite pipes

Czech Academy of Sciences Publication Activity Database

Hutař, Pavel; Náhlík, Luboš; Šestáková, Lucie; Ševčík, Martin; Knésl, Zdeněk; Nezbedová, E.

2010-01-01

Roč. 92, č. 5 (2010), s. 1120-1125 ISSN 0263-8223 R&D Projects: GA ČR GA106/09/0279 Institutional research plan: CEZ:AV0Z20410507 Keywords : Protective layers * Multi-layer pipes damage * Fracture mechanics * Bi-material interface * Generalized stress intensity factor Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.028, year: 2010

Simulation of crack propagation in fiber-reinforced concrete by fracture mechanics

International Nuclear Information System (INIS)

Zhang Jun; Li, Victor C.

2004-01-01

Mode I crack propagation in fiber-reinforced concrete (FRC) is simulated by a fracture mechanics approach. A superposition method is applied to calculate the crack tip stress intensity factor. The model relies on the fracture toughness of hardened cement paste (K IC ) and the crack bridging law, so-called stress-crack width (σ-δ) relationship of the material, as the fundamental material parameters for model input. As two examples, experimental data from steel FRC beams under three-point bending load are analyzed with the present fracture mechanics model. A good agreement has been found between model predictions and experimental results in terms of flexural stress-crack mouth opening displacement (CMOD) diagrams. These analyses and comparisons confirm that the structural performance of concrete and FRC elements, such as beams in bending, can be predicted by the simple fracture mechanics model as long as the related material properties, K IC and (σ-δ) relationship, are known

Prevalence of risk factors for fractures and use of DXA scanning in Danish women. A regional population-based study

DEFF Research Database (Denmark)

Rubin, K H; Abrahamsen, B; Hermann, A P

2011-01-01

.5% of those with more than 40 km to the nearest scanner had a history of DXA. Logistic regression analysis showed that distance, fracture risk, oral glucocorticoids, low-energy fracture, conditions associated with secondary osteoporosis, low BMI, history of falls, age 65–79 years, spouse status, and income......To determine the relationship between risk factors and use of DXA scans. Our study showed a relatively high use of DXA in low-risk women and the relatively low coverage in women with multiple risk factors. Moreover, distance to DXA clinics, age, and socio-economic factors are associated...... with the use of DXA. Introduction To determine the relationship between risk factors for fracture and use of DXA scans in Danish women in relation to distance to DXA clinics and socio-economic factors. Methods From the Danish National Civil Register we randomly selected 5,000 women aged 40–90 years living...

Simulating Hydraulic Fracturing: Failure in soft versus hard rocks

Science.gov (United States)

Aleksans, J.; Koehn, D.; Toussaint, R.

2017-12-01

In this contribution we discuss the dynamic development of hydraulic fractures, their evolution and the resulting seismicity during fluid injection in a coupled numerical model. The model describes coupling between a solid that can fracture dynamically and a compressible fluid that can push back at the rock and open fractures. With a series of numerical simulations we show how the fracture pattern and seismicity change depending on changes in depth, injection rate, Young's Modulus and breaking strength. Our simulations indicate that the Young's Modulus has the largest influence on the fracture dynamics and also the related seismicity. Simulations of rocks with a Young's modulus smaller than 10 GPa show dominant mode I failure and a growth of fracture aperture with a decrease in Young's modulus. Simulations of rocks with a higher Young's modulus than 10 GPa show fractures with a constant aperture and fracture growth that is mainly governed by a growth in crack length and an increasing amount of mode II failure. We propose that two distinct failure regimes are observed in the simulations, above 10 GPa rocks break with a constant critical stress intensity factor whereas below 10 GPa they break reaching a critical cohesion, i.e. a critical tensile strength. These results are very important for the prediction of fracture dynamics and seismicity during fluid injection, especially since we see a transition from one failure regime to another at around 10 GPa, a Young's modulus that lies in the middle of possible values for natural shale rocks.

Risk factors for post-operative periprosthetic fractures following primary total hip arthroplasty with a proximally coated double-tapered cementless femoral component

DEFF Research Database (Denmark)

Gromov, K; Bersang, A; Nielsen, C S

2017-01-01

ratio were recorded post-operatively. Periprosthetic fractures were identified and classified according to the Vancouver classification. Regression analysis was performed to identify risk factors for early periprosthetic fracture. RESULTS: The mean follow-up was 713 days (1 to 2058). A total of 48......AIMS: The aim of this study was to identify patient- and surgery-related risk factors for sustaining an early periprosthetic fracture following primary total hip arthroplasty (THA) performed using a double-tapered cementless femoral component (Bi-Metric femoral stem; Biomet Inc., Warsaw, Indiana...... periprosthetic fractures (3.0%) were identified during the follow-up and median time until fracture was 16 days, (interquartile range 10 to 31.5). Patients with femoral Dorr type C had a 5.2 times increased risk of post-operative periprosthetic fracture compared with type B, while female patients had a near...

Stress-intensity factor equations for cracks in three-dimensional finite bodies

Science.gov (United States)

Newman, J. C., Jr.; Raju, I. S.

1981-01-01

Empirical stress intensity factor equations are presented for embedded elliptical cracks, semi-elliptical surface cracks, quarter-elliptical corner cracks, semi-elliptical surface cracks at a hole, and quarter-elliptical corner cracks at a hole in finite plates. The plates were subjected to remote tensile loading. Equations give stress intensity factors as a function of parametric angle, crack depth, crack length, plate thickness, and where applicable, hole radius. The stress intensity factors used to develop the equations were obtained from three dimensional finite element analyses of these crack configurations.

Calculation of mixed mode stress intensity factors using an alternating method

International Nuclear Information System (INIS)

Sakai, Takayuki

1999-01-01

In this study, mixed mode stress intensity factors (K I and K II ) of a square plate with a notch were calculated using a finite element alternating method. The obtained results were compared with the ones by a finite element method, and it was shown that the finite element alternating method can accurately estimate mixed mode stress intensity factors. Then, using this finite element alternating method, mixed mode stress intensity factors were calculated as changing the size and position of the notch, and its simplified equations were proposed. (author)

Simulation of complex fracture networks influenced by natural fractures in shale gas reservoir

Directory of Open Access Journals (Sweden)

Zhao Jinzhou

2014-10-01

Full Text Available When hydraulic fractures intersect with natural fractures, the geometry and complexity of a fracture network are determined by the initiation and propagation pattern which is affected by a number of factors. Based on the fracture mechanics, the criterion for initiation and propagation of a fracture was introduced to analyze the tendency of a propagating angle and factors affecting propagating pressure. On this basis, a mathematic model with a complex fracture network was established to investigate how the fracture network form changes with different parameters, including rock mechanics, in-situ stress distribution, fracture properties, and frac treatment parameters. The solving process of this model was accelerated by classifying the calculation nodes on the extending direction of the fracture by equal pressure gradients, and solving the geometrical parameters prior to the iteration fitting flow distribution. With the initiation and propagation criterion as the bases for the propagation of branch fractures, this method decreased the iteration times through eliminating the fitting of the fracture length in conventional 3D fracture simulation. The simulation results indicated that the formation with abundant natural fractures and smaller in-situ stress difference is sufficient conditions for fracture network development. If the pressure in the hydraulic fractures can be kept at a high level by temporary sealing or diversion, the branch fractures will propagate further with minor curvature radius, thus enlarging the reservoir stimulation area. The simulated shape of fracture network can be well matched with the field microseismic mapping in data point range and distribution density, validating the accuracy of this model.

Risk factors for falls with severe fracture in elderly people living in a middle-income country: a case control study

OpenAIRE

Coutinho, Evandro SF; Fletcher, Astrid; Bloch, Katia V; Rodrigues, Laura C

2008-01-01

Abstract Background Fracture after falling has been identified as an important problem in public health. Most studies of risk factors for fractures due to falls have been carried out in developed countries, although the size of the elderly population is increasing fast in middle income countries. The objective of this paper is to identify risk factors for fall related to severe fractures in those aged 60 or more in a middle-income country. Methods A case-control study was carried out in Rio d...

The factors influencing the decision making of operative treatment for proximal humeral fractures

NARCIS (Netherlands)

Hageman, Michiel G. J. S.; Jayakumar, Prakash; King, John D.; Guitton, Thierry G.; Doornberg, Job N.; Ring, David

2015-01-01

The factors influencing the decision making of operative treatment for fractures of the proximal humerus are debated. We hypothesized that there is no difference in treatment recommendations between surgeons shown radiographs alone and those shown radiographs and patient information. Secondarily, we

The factors influencing the decision making of operative treatment for proximal humeral fractures

NARCIS (Netherlands)

Hageman, M.G.; Jayakumar, P.; King, J.D.; Guitton, T.G.; Doornberg, J.N.; Ring, D.; Poelhekke, L.M.S.J.; et al.,

2015-01-01

BACKGROUND: The factors influencing the decision making of operative treatment for fractures of the proximal humerus are debated. We hypothesized that there is no difference in treatment recommendations between surgeons shown radiographs alone and those shown radiographs and patient information.

on GAGD EOR in Naturally Fractured Reservoirs

Directory of Open Access Journals (Sweden)

Misagh Delalat

2013-01-01

Full Text Available The gas-assisted gravity drainage (GAGD process is designed and practiced based on gravity drainage idea and uses the advantage of density difference between injected CO2 and reservoir oil. In this work, one of Iran western oilfields was selected as a case study and a sector model was simulated based on its rock and fluid properties. The pressure of CO2 gas injection was close to the MMP of the oil, which was measured 1740 psia. Both homogeneous and heterogeneous types of fractures were simulated by creating maps of permeability and porosity. The results showed that homogeneous fractures had the highest value of efficiency, namely 40%; however, in heterogeneous fractures, the efficiency depended on the value of fracture density and the maximum efficiency was around 37%. Also, the effect of injection rate on two different intensities of fracture was studied and the results demonstrated that the model having higher fracture intensity had less limitation in increasing the CO2 injection rate; furthermore, its BHP did not increase intensively at higher injection rates either. In addition, three different types of water influxes were inspected on GAGD performance to simulate active, partial, and weak aquifer. The results showed that strong aquifer had a reverse effect on the influence of GAGD and almost completely disabled the gravity drainage mechanism. Finally, we inventively used a method to weaken the aquifer strength, and thus the gravity drainage revived and efficiency started to increase as if there was no aquifer.

The epidemiology of wrist fractures in older men: the Osteoporotic Fractures in Men (MrOS) study.

Science.gov (United States)

Wright, N C; Hooker, E R; Nielson, C M; Ensrud, K E; Harrison, S L; Orwoll, E S; Barrett-Connor, E

2018-04-01

There is limited wrist fracture information on men. Our goal was to calculate frequency and identify risk factors for wrist fracture in the Osteoporotic Fractures in Men (MrOS) study. We confirmed that fracture history and certain medications are predictors, and identified novel predictors including markers of kidney function and physical performance. To calculate the incidence of wrist fractures and their risk factors in older community-dwelling men from the US Osteoporotic Fractures in Men (MrOS) study. Using triannual postcards, we identified incident wrist fractures (centrally confirmed by radiology) in men aged ≥ 65. Potential risk factors included the following: demographics, lifestyle, bone mineral density (BMD), selected medications, biomarkers, and physical function and performance measures. Both baseline and time-varying models were adjusted for age, race/ethnicity, MrOS geographic location, and competing mortality risks. We observed 97 incident wrist fractures among 5875 men followed for an average of 10.8 years. The incidence of wrist fracture was 1.6 per 1000 person-years overall and ranged from 1.0 among men aged 65-69 to 2.4 among men age ≥ 80. Significant predictors included the following: fracture history after age 50 [hazard ratio (95% CI): 2.48 (1.65, 3.73)], high serum phosphate [1.25 (1.02, 1.53)], use of selective serotonin receptor inhibitor (SSRI) [3.60 (1.96, 6.63), decreased right arm BMD [0.49 (0.37, 0.65) per SD increase], and inability to perform the grip strength test [3.38 (1.24, 9.25)]. We did not find associations with factors commonly associated with wrist and other osteoporosis fractures like falls, diabetes, calcium and vitamin D intake, and alcohol intake. Among these older, community-dwelling men, we confirmed that fracture history is a strong predictor of wrist fractures in men. Medications such as SSRIs and corticosteroids also play a role in wrist fracture risk. We identified novel risk factors including kidney

Prevention of non-ductile fracture in 6061-T6 aluminum nuclear pressure vessels

International Nuclear Information System (INIS)

Yahr, G.T.

1995-01-01

The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Committee has approved rules for the use of 6061-T6 and 6061-T651 aluminum for the construction of Class 1 welded nuclear pressure vessels for temperatures not exceeding 149 C (300 F). Nuclear Code Case N-519 allows the use of this aluminum in the construction of low temperature research reactors such as the Advanced Neutron Source. The rules for protection against non-ductile fracture are discussed. The basis for a value of 25.3 MPa √m (23 ksi √in.) for the critical or reference stress intensity factor for use in the fracture analysis is presented. Requirements for consideration of the effects of neutron irradiation on the fracture toughness are discussed

Comparison of fracture toughness values of normal and high strength concrete determined by three point bend and modified disk-shaped compact tension specimens

Czech Academy of Sciences Publication Activity Database

Seitl, Stanislav; Ríjos, J. D.; Cifuentes, H.

2017-01-01

Roč. 11, č. 42 (2017), s. 56-65 ISSN 1971-8993 R&D Projects: GA ČR(CZ) GA16-18702S; GA MŠk LM2015069 Institutional support: RVO:68081723 Keywords : Concrete * Stress intensity factors * T-stress * Compact tension test * Fracture behavior * Fracture toughness Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis

Assessment of radiological vertebral fractures in HIV-infected patients: clinical implications and predictive factors.

Science.gov (United States)

Gazzola, L; Savoldi, A; Bai, F; Magenta, A; Dziubak, M; Pietrogrande, L; Tagliabue, L; Del Sole, A; Bini, T; Marchetti, G; d'Arminio Monforte, A

2015-10-01

The aim of this study was to evaluate the clinical impact of including lateral spine X-ray in the screening of bone diseases in HIV-positive patients. A total of 194 HIV-positive patients underwent dual-energy X-ray absorptiometry (DEXA), lateral spine X-ray and bone biochemical analysis. Vertebral fractures were identified using a morphometric analysis of X-rays and classified using the semiquantitative scoring system of Genant et al. For each patient, a spine deformity index (SDI) score was calculated by summing the grades of vertebral deformities. Reductions in vertebral body height of > 25% were considered vertebral fractures, and those Risk factors associated with vertebral fractures were evaluated by univariate and multivariate analysis. Vertebral fractures were detected in 24 patients (12.4%) and vertebral deformities in 17 patients (8.7%); 153 patients (78.9%) did not show any vertebral deformity. Among patients with fractures, only two with SDI > 10 reported lumbar pain; the remaining were asymptomatic. Patients over 50 years old showed a higher prevalence of vertebral fracture [24.4% versus 11.8% in patients 41-50 years old (P = 0.05) and 1.9% in patients ≤ 40 years old (P = 0.04)]. No significant increase in the prevalence according to bone mineral density (BMD) reduction was observed, and 70% of fractures were diagnosed in nonosteoporotic patients. Older age [adjusted odds ratio 1.09; 95% confidence interval (CI) 1.03-1.13; P = 0.001] and steroid use (adjusted odds ratio 3.64; 95% CI 1.29-10.3; P = 0.01) were independently associated with vertebral fracture; no association was found with HIV- or highly active antiretroviral therapy (HAART)-related variables. A prevalence of vertebral fractures of 12.4% was observed in our HIV-positive cohort. Given that two-thirds of fractures occurred in nonosteoporotic patients, spine X-ray may be considered in patients at increased risk, irrespective of BMD; that is, in elderly patients

Flow characteristics through a single fracture of artificial fracture system

International Nuclear Information System (INIS)

Park, Byoung Yoon; Bae, Dae Seok; Kim, Chun Soo; Kim, Kyung Su; Koh, Young Kwon; Jeon, Seok Won

2001-04-01

Fracture flow in rock masses is one of the most important issues in petroleum engineering, geology, and hydrogeology. Especially, in case of the HLW disposal, groundwater flow in fractures is an important factor in the performance assessment of the repository because the radionuclides move along the flowing groundwater through fractures. Recently, the characterization of fractures and the modeling of fluid flow in fractures are studied by a great number of researchers. Among those studies, the hydraulic behavior in a single fracture is one of the basic issues for understanding of fracture flow in rockmass. In this study, a fluid flow test in the single fracture made of transparent epoxy replica was carried out to obtain the practical exponent values proposed from the Cubic law and to estimate the flow rates through a single fracture. Not only the relationship between flow rates and the geometry of fracture was studied, but also the various statistical parameters of fracture geometry were compared to the effective transmissivity data obtained from computer simulation.

Development of Deterministic and Probabilistic Fracture Mechanics Analysis Code PROFAS-RV for Reactor Pressure Vessel - Progress of the Work

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Min; Lee, Bong Sang [KAERI, Daejeon (Korea, Republic of)

2016-05-15

In this study, a deterministic/probabilistic fracture mechanics analysis program for reactor pressure vessel, PROFAS-RV, is developed. This program can evaluate failure probability of RPV using recent radiation embrittlement model of 10CFR50.61a and stress intensity factor calculation method of RCC-MRx code as well as the required basic functions of PFM program. Applications of some new radiation embrittlement model, material database, calculation method of stress intensity factors, and others which can improve fracture mechanics assessment of RPV are introduced. The purpose of this study is to develop a probabilistic fracture mechanics (PFM) analysis program for RPV considering above modification and application of newly developed models and calculation methods. In this paper, it deals with the development progress of the PFM analysis program for RPV, PROFAS-RV. The PROFAS-RV is being tested with other codes, and it is expected to revise and upgrade by reflecting the latest model and calculation method continuously. These efforts can minimize the uncertainty of the integrity evaluation for the reactor pressure vessel.

Fracture characterization and discrimination criteria for karst and tectonic fractures in the Ellenburger Group, West Texas: Implications for reservoir and exploration models

Energy Technology Data Exchange (ETDEWEB)

Hoak, T.E. [Science Applications International Corp., Germantown, MD (United States)]|[Kestrel Geoscience, Littleton, CO (United States); Sundberg, K.R. [Phillips Petroleum Co., Bartlesville, OK (United States); Deyhim, P. [Oklahoma State Univ., Stillwater, OK (United States); Ortoleva, P. [Indiana Univ., Bloomington, IN (United States). Lab. for Computational Geodynamics

1998-12-31

In the Ellenburger Group fractured dolomite reservoirs of West Texas, it is extremely difficult to distinguish between multiple phases of karst-related fracturing, modifications to the karst system during burial, and overprinting tectonic fractures. From the analyses of drill core, the authors developed criteria to distinguish between karst and tectonic fractures. In addition, they have applied these criteria within the context of a detailed diagenetic cement history that allows them to further refine the fracture genesis and chronology. In these analyses, the authors evaluated the relationships between fracture intensity, morphologic attributes, host lithology, fracture cement, and oil-staining. From this analysis, they have been able to characterize variations in Ellenburger tectonic fracture intensity by separating these fractures from karst-related features. In general, the majority of fracturing in the Ellenburger is caused by karst-related fracturing although a considerable percentage is caused by tectonism. These findings underscore the importance of considering the complete geologic evolution of a karst reservoir during exploration and field development programs. The authors have been able to more precisely define the spatial significance of the fracture data sets by use of oriented core from Andector Field. They have also demonstrated the importance of these results for exploration and reservoir development programs in West Texas, and the potential to extrapolate these results around the globe. Given the historic interest in the large hydrocarbon reserves in West Texas carbonate reservoirs, results of this study will have tremendous implications for exploration and production strategies targeting vuggy, fractured carbonate systems not only in West Texas, but throughout the globe.

Investigation of translaminar fracture in fibrereinforced composite laminates---applicability of linear elastic fracture mechanics and cohesive-zone model

Science.gov (United States)

Hou, Fang

With the extensive application of fiber-reinforced composite laminates in industry, research on the fracture mechanisms of this type of materials have drawn more and more attentions. A variety of fracture theories and models have been developed. Among them, the linear elastic fracture mechanics (LEFM) and cohesive-zone model (CZM) are two widely-accepted fracture models, which have already shown applicability in the fracture analysis of fiber-reinforced composite laminates. However, there remain challenges which prevent further applications of the two fracture models, such as the experimental measurement of fracture resistance. This dissertation primarily focused on the study of the applicability of LEFM and CZM for the fracture analysis of translaminar fracture in fibre-reinforced composite laminates. The research for each fracture model consisted of two sections: the analytical characterization of crack-tip fields and the experimental measurement of fracture resistance parameters. In the study of LEFM, an experimental investigation based on full-field crack-tip displacement measurements was carried out as a way to characterize the subcritical and steady-state crack advances in translaminar fracture of fiber-reinforced composite laminates. Here, the fiber-reinforced composite laminates were approximated as anisotropic solids. The experimental investigation relied on the LEFM theory with a modification with respect to the material anisotropy. Firstly, the full-field crack-tip displacement fields were measured by Digital Image Correlation (DIC). Then two methods, separately based on the stress intensity approach and the energy approach, were developed to measure the crack-tip field parameters from crack-tip displacement fields. The studied crack-tip field parameters included the stress intensity factor, energy release rate and effective crack length. Moreover, the crack-growth resistance curves (R-curves) were constructed with the measured crack-tip field parameters

Factors associated with an increased risk of vertebral fracture in monoclonal gammopathies of undetermined significance

International Nuclear Information System (INIS)

Piot, J M; Royer, M; Schmidt-Tanguy, A; Hoppé, E; Gardembas, M; Bourrée, T; Hunault, M; François, S; Boyer, F; Ifrah, N; Renier, G; Chevailler, A; Audran, M; Chappard, D; Libouban, H; Mabilleau, G; Legrand, E; Bouvard, B

2015-01-01

Monoclonal gammopathies of undetermined significance (MGUS) have been shown to be associated with an increased risk of fractures. This study describes prospectively the bone status of MGUS patients and determines the factors associated with vertebral fracture. We included prospectively 201 patients with MGUS, incidentally discovered, and with no known history of osteoporosis: mean age 66.6±12.5 years, 48.3% women, 51.7% immunoglobulin G (IgG), 33.3% IgM and 10.4% IgA. Light chain was kappa in 64.2% patients. All patients had spinal radiographs and bone mineral density measurement in addition to gammopathy assessment. At least one prevalent non-traumatic vertebral fracture was discovered in 18.4% patients and equally distributed between men and women. Fractured patients were older, had a lower bone density and had also more frequently a lambda light chain isotype. Compared with patients with κ light chain, the odds ratio of being fractured for patients with λ light chain was 4.32 (95% confidence interval 1.80–11.16; P=0.002). These results suggest a high prevalence of non-traumatic vertebral fractures in MGUS associated with lambda light chain isotype and not only explained by low bone density

Is warfarin usage a risk factor for osteoporotic fractures? A cohort study in the emergency department

Directory of Open Access Journals (Sweden)

Genady Drozdinsky

2017-04-01

Full Text Available Background Several studies have examined the association between warfarin sodium use and risk of osteoporotic fractures with conflicting results. Our study addresses this question, for the first time regarding patients attending emergency department (ED. Aims The aim of this study was to retrospectively detect whether there is higher rate of usage of warfarin sodium in patients with osteoporotic fractures attending an ED. Methods This is a retrospective study from patients' computerized charts. All individuals >65 years old who had an osteoporotic fracture and attended an ED in a tertiary hospital were compared with a similar group of elderly individuals >65 years old without an osteoporotic fracture who attended the ED for a cause other than an osteoporotic fracture. Results This study included 328 patients who were evaluated in the years 2005–2016. Overall, 164 individuals with a typical osteoporotic fracture (hip -66 patients (40 per cent, spine- 92 patients (56 per cent, humerus -4 patients (2 per cent, radius -13 patients (8 per cent were identified and compared with a matched group of elderly individuals who were evaluated in the ED for other complaints. Warfarin sodium was used in 61 individuals (19 per cent in the entire cohort, 34 in the fracture group and 27 in the non-fracture group (p=0.324. Conclusion In elderly patients, attending an ED, warfarin sodium use does not seem to be a risk factor for an osteoporotic fracture

Fracture Anisotropy and Toughness in the Mancos Shale: Implications for crack-growth geometry

Science.gov (United States)

Chandler, M. R.; Meredith, P. G.; Brantut, N.; Crawford, B. R.

2013-12-01

The hydraulic fracturing of gas-shales has drawn attention to the fundamental fracture properties of shales. Fracture propagation is dependent on a combination of the in-situ stress field, the fracturing fluid and pressure, and the mechanical properties of the shale. However, shales are strongly anisotropic, and there is a general paucity of available experimental data on the anisotropic mechanical properties of shales in the scientific literature. The mode-I stress intensity factor, KI, quantifies the concentration of stress at crack tips. The Fracture Toughness of a linear elastic material is then defined as the critical value of this stress intensity factor; KIc, beyond which rapid catastrophic crack growth occurs. However, shales display significant non-linearity, which produces hysteresis during experimental cyclic loading. This allows for the calculation of a ductility coefficient using the residual displacement after successive loading cycles. From this coefficient, a ductility corrected Fracture Toughness value, KIcc can be determined. In the Mancos Shale this ductility correction can be as large as 60%, giving a Divider orientation KIcc value of 0.8 MPa.m0.5. Tensile strength and mode-I Fracture Toughness have been experimentally determined for the Mancos Shale using the Brazil Disk and Short-Rod methodologies respectively. The three principal fracture orientations; Arrester, Divider and Short-Transverse were all analysed. A significant anisotropy is observed in the tensile strength, with the Arrester value being 1.5 times higher than the Short-Transverse value. Even larger anisotropy is observed in the Fracture Toughness, with KIcc in the Divider and Arrester orientations being around 1.8 times that in the Short-Transverse orientation. For both tensile strength and fracture toughness, the Short-Transverse orientation, where the fracture propagates in the bedding plane in a direction parallel to the bedding, is found to have significantly lower values than

Midshaft clavicle fractures with associated ipsilateral acromioclavicular joint dislocations: Incidence and risk factors.

Science.gov (United States)

Ottomeyer, Christina; Taylor, Benjamin C; Isaacson, Mark; Martinez, Lara; Ebaugh, Pierce; French, Bruce G

2017-02-01

Simultaneous ipsilateral clavicle and acromioclavicular (AC) joint injury have been infrequently reported in the literature at this time. The purpose of this study was to assess incidence as well as assess risk factors for this dual injury pattern. We performed a retrospective review of a prospectively collected database (Level III evidence), evaluating 383 adult patients without previous shoulder girdle injury or trauma with a minimum 1-year follow-up who sustained a displaced diaphyseal clavicle fracture. All patients in the study underwent either nonoperative management or surgical reduction and stabilization of a diaphyseal clavicle fracture with a plate and screw construct. Study subjects were followed with serial radiographs. Clavicle and shoulder radiographs, as well as chest radiographs and contralateral films in questionable cases, were used to assess for acromioclavicular joint injury in both operative and nonoperative groups. Additional data was collected on concurrent injuries, patient demographics, fracture characteristics, fixation techniques, surgical/post-operative data, and operative or nonoperative treatment. We found that 13/183 (7.1%) of patients undergoing fixation of a diaphyseal clavicle fracture had an ipsilateral AC joint injury, while 13/200 (6.5%) of patients undergoing conservative management had an ipsilateral AC joint injury. Critical analysis of the data revealed that presence of ipsilateral scapular body fractures, and a likely incidental association with superior plating fixation, were associated with an increased rate of this injury pattern. Ipsilateral clavicle fracture and AC joint injury is much more common than traditionally believed, with an incidence of 6.8% overall. It is unknown how the presence of an associated AC injury influences outcome, as AC injury was not universally symptomatic. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lifestyle factors and site-specific risk of hip fracture in community dwelling older women – a 13-year prospective population-based cohort study

Directory of Open Access Journals (Sweden)

Määttä Mikko

2012-09-01

Full Text Available Abstract Background Several risk factors are associated to hip fractures. It seems that different hip fracture types have different etiologies. In this study, we evaluated the lifestyle-related risk factors for cervical and trochanteric hip fractures in older women over a 13-year follow-up period. Methods The study design was a prospective, population-based study consisting of 1681 women (mean age 72 years. Seventy-three percent (n = 1222 participated in the baseline measurements, including medical history, leisure-time physical activity, smoking, and nutrition, along with body anthropometrics and functional mobility. Cox regression was used to identify the independent predictors of cervical and trochanteric hip fractures. Results During the follow-up, 49 cervical and 31 trochanteric fractures were recorded. The women with hip fractures were older, taller, and thinner than the women with no fractures (p  Conclusions Impaired functional mobility, physical inactivity, and low body mass may increase the risk for hip fractures with different effects at the cervical and trochanteric levels.

Rib Fracture Fixation: Indications and Outcomes.

Science.gov (United States)

Senekjian, Lara; Nirula, Raminder

2017-01-01

Rib fractures are a frequently identified injury in the trauma population. Not only are multiple rib fractures painful, but they are associated with an increased risk of adverse outcomes. Pneumonia in particular can be devastating, especially to an elderly patient, but other complications such as prolonged ventilation and increased intensive care and hospital durations of stay have a negative impact on the patient. Computed tomography scan is the best modality to diagnosis rib fractures but the treatment of fractures is still evolving. Currently patient care involves a multidisciplinary approach that includes pain control, aggressive pulmonary therapy, and possibly surgical fixation. Copyright © 2016 Elsevier Inc. All rights reserved.

Stress intensity factor analyses of surface cracks in three-dimensional structures

International Nuclear Information System (INIS)

Miyazaki, Noriyuki; Shibata, Katsuyuki; Watanabe, Takayuki; Tagata, Kazunori.

1983-11-01

The stress intensity factor analyses of surface cracks in various three-dimensional structures were performed using the finite element computer program EPAS-J1. The results obtained by EPAS-J1 were compared with other finite element solutions or results obtained by the simplified estimation methods. Among the simplified estimation methods, the equations proposed by Newman and Raju give the distributions of the stress intensity factor along a crack front, which were compared with the result obtained by EPAS-J1. It was confirmed by comparing the results that EPAS-J1 gives reasonable stress intensity factors of surface cracks in three-dimensional structures. (author)

Effects of overload on the threshold stress intensity factor for SCC

International Nuclear Information System (INIS)

Takahashi, Koji; Ando, Kotoji; Miyazaki, Yuji; Hashikura, Yasuaki

2009-01-01

The effects of overload on the threshold stress intensity factor for stress corrosion crack (K ISCC ) of stainless steel were studied. Tensile overload was applied to a wedge opening loaded (WOL) specimen of SUS316. Then, SCC tests were carried out to determine the resultant K ISCC . As a result, the apparent value of K ISCC increases as increasing a stress intensity factor by tensile overload (K OV ). The effects of tensile overload on K ISCC and the threshold stress intensity factor range for fatigue (ΔK th ) were compared. It was found that the effects of tensile overload on K ISCC were larger than that on ΔK th . (author)

Viscoplasticity and the dynamics of brittle fracture

International Nuclear Information System (INIS)

Langer, J. S.

2000-01-01

I propose a model of fracture in which the curvature of the crack tip is a relevant dynamical variable and crack advance is governed solely by plastic deformation of the material near the tip. This model is based on a rate-and-state theory of plasticity introduced in earlier papers by Falk, Lobkovsky, and myself. In the approximate analysis developed here, fracture is brittle whenever the plastic yield stress is nonzero. The tip curvature finds a stable steady-state value at all loading strengths, and the tip stress remains at or near the plastic yield stress. The crack speed grows linearly with the square of the effective stress intensity factor above a threshold that depends on the surface tension. This result provides a possible answer to the fundamental question of how breaking stresses are transmitted through plastic zones near crack tips. (c) 2000 The American Physical Society

Risk factors for falls with severe fracture in elderly people living in a middle-income country: a case control study

Directory of Open Access Journals (Sweden)

Bloch Katia V

2008-08-01

Full Text Available Abstract Background Fracture after falling has been identified as an important problem in public health. Most studies of risk factors for fractures due to falls have been carried out in developed countries, although the size of the elderly population is increasing fast in middle income countries. The objective of this paper is to identify risk factors for fall related to severe fractures in those aged 60 or more in a middle-income country. Methods A case-control study was carried out in Rio de Janeiro-Brazil based general hospitals between 2002–2003. Two hundred-fifty hospitalised cases of fracture were matched with 250 community controls by sex, age group and living area. Data were collected for socio-demographic variables, health status and drugs used before the fall. A conditional logistic regression model was fitted to identify variables associated with the risk of fall related severe fracture. Results Low body mass index, cognitive impairment, stroke and lack of urine control were associated with increased risk of severe fall related fractures. Benzodiazepines and muscle relaxants were also related to an increased risk of severe fractures while moderate use of alcohol was associated with reduced risk. Conclusion Although the association between benzodiazepines and fractures due to fall has been consistently demonstrated for old people, this has not been the case for muscle relaxant drugs. The decision to prescribe muscle relaxants for elderly people should take into account the risk of severe fracture associated with these drugs.

Risk factors for falls with severe fracture in elderly people living in a middle-income country: a case control study.

Science.gov (United States)

Coutinho, Evandro S F; Fletcher, Astrid; Bloch, Katia V; Rodrigues, Laura C

2008-08-26

Fracture after falling has been identified as an important problem in public health. Most studies of risk factors for fractures due to falls have been carried out in developed countries, although the size of the elderly population is increasing fast in middle income countries. The objective of this paper is to identify risk factors for fall related to severe fractures in those aged 60 or more in a middle-income country. A case-control study was carried out in Rio de Janeiro-Brazil based general hospitals between 2002-2003. Two hundred-fifty hospitalised cases of fracture were matched with 250 community controls by sex, age group and living area. Data were collected for socio-demographic variables, health status and drugs used before the fall. A conditional logistic regression model was fitted to identify variables associated with the risk of fall related severe fracture. Low body mass index, cognitive impairment, stroke and lack of urine control were associated with increased risk of severe fall related fractures. Benzodiazepines and muscle relaxants were also related to an increased risk of severe fractures while moderate use of alcohol was associated with reduced risk. Although the association between benzodiazepines and fractures due to fall has been consistently demonstrated for old people, this has not been the case for muscle relaxant drugs. The decision to prescribe muscle relaxants for elderly people should take into account the risk of severe fracture associated with these drugs.

Nontraumatic femur fracture in an oligomenorrheic athlete.

Science.gov (United States)

Dugowson, C E; Drinkwater, B L; Clark, J M

1991-12-01

Exercise-associated amenorrhea is the cessation of menses in a woman following onset of training or an increase in training intensity. Its physiologic basis is characterized by consistently low levels of gonadotropin and ovarian hormones, but the underlying cause of this phenomenon is unknown. Although osteopenia has been described in amenorrheic women athletes, it has been primarily a laboratory diagnosis. Several recent studies have described a significantly lower bone mineral density (BMD) in the lumbar spine of amenorrheic athletes. Marcus et al. also reported an increased number of metatarsal and tibial stress fractures in a group of amenorrheic women. We report here the first case of a nontraumatic femur fracture in an amenorrheic athlete. A 32-yr-old white female, with four prior fibular stress fractures, suffered a left femoral shaft fracture during the 13th mile of a half-marathon. The fracture was successfully internally fixed. Biochemical studies showed no metabolic abnormality. Bone mineral density of the lumbar spine, femoral neck, tibia, and fibula were below the mean for both eumenorrheic and amenorrheic female athletes. Exercise-associated amenorrhea is a medical problem that may have serious implications for both competitive and high-intensity recreational female athletes.

Fracture risk in patients with type 2 diabetes mellitus and possible risk factors: a systematic review and meta-analysis

Directory of Open Access Journals (Sweden)

Moayeri A

2017-04-01

Full Text Available Ardeshir Moayeri,1 Mahmoud Mohamadpour,2 Seyedeh Fatemeh Mousavi,3 Ehsan Shirzadpour,2 Safoura Mohamadpour,3 Mansour Amraei4 1Department of Anatomy, 2Department of Biochemistry, Faculty of Medicine, 3Department of Epidemiology, Prevention of Psychosocial Injuries Research Center, 4Department of Physiology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran Aim: Patients with type 2 diabetes mellitus (T2DM have an increased risk of bone fractures. A variable increase in fracture risk has been reported depending on skeletal site, diabetes duration, study design, insulin use, and so on. The present meta-analysis aimed to investigate the association between T2DM with fracture risk and possible risk factors.Methods: Different databases including PubMed, Institute for Scientific Information, and Scopus were searched up to May 2016. All epidemiologic studies on the association between T2DM and fracture risk were included. The relevant data obtained from these papers were analyzed by a random effects model and publication bias was assessed by funnel plot. All analyses were done by R software (version 3.2.1 and STATA (version 11.1.Results: Thirty eligible studies were selected for the meta-analysis. We found a statistically significant positive association between T2DM and hip, vertebral, or foot fractures and no association between T2DM and wrist, proximal humerus, or ankle fractures. Overall, T2DM was associated with an increased risk of any fracture (summary relative risk =1.05, 95% confidence interval: 1.04, 1.06 and increased with age, duration of diabetes, and insulin therapy.Conclusion: Our findings strongly support an association between T2DM and increased risk of overall fracture. These findings emphasize the need for fracture prevention strategies in patients with diabetes. Keywords: diabetes mellitus, fractures, bone, osteoporosis, risk factors, meta-analysis

Wedge splitting test method: quantification of influence of glued marble plates by two-parameter fracture mechanics

Czech Academy of Sciences Publication Activity Database

Seitl, Stanislav; Nieto Garcia, B.; Merta, I.

2014-01-01

Roč. 30, OCT (2014), s. 174-181 ISSN 1971-8993 R&D Projects: GA MŠk(CZ) 7AMB14AT012 Institutional support: RVO:68081723 Keywords : Wedge splitting test * T-stress * K-calibration curves * Stress intensity factor * Concrete fracture test Subject RIV: JL - Materials Fatigue, Friction Mechanics

Lifestyle factors and site-specific risk of hip fracture in community dwelling older women – a 13-year prospective population-based cohort study

Science.gov (United States)

2012-01-01

Background Several risk factors are associated to hip fractures. It seems that different hip fracture types have different etiologies. In this study, we evaluated the lifestyle-related risk factors for cervical and trochanteric hip fractures in older women over a 13-year follow-up period. Methods The study design was a prospective, population-based study consisting of 1681 women (mean age 72 years). Seventy-three percent (n = 1222) participated in the baseline measurements, including medical history, leisure-time physical activity, smoking, and nutrition, along with body anthropometrics and functional mobility. Cox regression was used to identify the independent predictors of cervical and trochanteric hip fractures. Results During the follow-up, 49 cervical and 31 trochanteric fractures were recorded. The women with hip fractures were older, taller, and thinner than the women with no fractures (p trochanteric fractures (HR = 3.4, 95% CI 1.8-6.6, and HR = 5.3, 95% CI 2.5-11.4, respectively). Low baseline physical activity was associated with an increased risk of hip fracture, especially in the cervical region (HR = 2.5, 95% CI 1.3-4.9). A decrease in cervical fracture risk (p = 0.002) was observed with physically active individuals compared to their less active peers (categories: very low or low, moderate, and high). Moderate coffee consumption and hypertension decreased the risk of cervical fractures (HR = 0.4, 95% CI 0.2-0.8, for both), while smoking was a predisposing factor for trochanteric fractures (HR = 3.2, 95% CI 1.1-9.3). Conclusions Impaired functional mobility, physical inactivity, and low body mass may increase the risk for hip fractures with different effects at the cervical and trochanteric levels. PMID:22978821

Cough-induced rib fractures.

Science.gov (United States)

Hanak, Viktor; Hartman, Thomas E; Ryu, Jay H

2005-07-01

To define the demographic, clinical, and radiological features of patients with cough-induced rib fractures and to assess potential risk factors. For this retrospective, single-center study, we identified all cases of cough-induced rib fractures diagnosed at the Mayo Clinic in Rochester, Minn, over a 9-year period between January 1, 1996, and January 31, 2005. Bone densitometry data from patients' medical records were analyzed, and T scores were used to classify patients into bone density categories. The mean +/- SD age of the 54 study patients at presentation was 55+/-17 years, and 42 patients (78%) were female. Patients presented with chest wall pain after onset of cough. Rib fracture was associated with chronic cough (> or =3 weeks' duration) in 85% of patients. Rib fractures were documented by chest radiography, rib radiography, computed tomography, or bone scan. Chest radiography had been performed in 52 patients and revealed rib fracture in 30 (58%). There were 112 fractured ribs in 54 patients. One half of patients had more than one fractured rib. Right-sided rib fractures alone were present in 17 patients (26 fractured ribs), left-sided in 23 patients (35 fractured ribs), and bilateral in 14 patients (51 fractured ribs). The most commonly fractured rib on both sides was rib 6. The fractures were most common at the lateral aspect of the rib cage. Bone densitometry was done in 26 patients and revealed osteopenia or osteoporosis in 17 (65%). Cough-induced rib fractures occur primarily in women with chronic cough. Middle ribs along the lateral aspect of the rib cage are affected most commonly. Although reduced bone density is likely a risk factor, cough-induced rib fractures can occur in the presence of normal bone density.

Factors related to mortality after osteoporotic hip fracture treatment at Chiang Mai University Hospital, Thailand, during 2006 and 2007.

Science.gov (United States)

Chaysri, Rathasart; Leerapun, Taninnit; Klunklin, Kasisin; Chiewchantanakit, Siripong; Luevitoonvechkij, Sirichai; Rojanasthien, Sattaya

2015-01-01

To investigate the one-year mortality rate after osteoporotic hip fracture and to identify factors associated with that mortality rate. A retrospective review of 275 osteoporotic patients who sustained a low-trauma hip fracture and were admitted in Chiang Mai University Hospital during January 1, 2006 to December 31, 2007 was accomplished. Eligibility criteria were defined as age over 50 years, fracture caused by a simple fall and not apathologicalfracture caused by cancer or infection. Results of this one-year mortality rate study were compared to studies of hip fracture patient mortality in 1997 and the period 1998-2003. The average one-year mortality rate in 2006-2007 was 21.1%. Factors correlated with higher mortality were non-operative treatment, delayed surgical treatment, and absence of medical treatment for osteoporosis. The 2006-2007 mortality rate was slightly higher than for the 1997 and 1998-2003 periods. The one-year mortality rate after osteoporotic hip fracture of 21.1% was approximately 9.3 times the mortality rate for the same age group in the general population, indicating that treatment of osteoporosis as a means of helping prevent hip fracture is very important for the individual, the family, and society as a whole.

Data Mining Activity for Bone Discipline: Calculating a Factor of Risk for Hip Fracture in Long-Duration Astronauts

Science.gov (United States)

Ellman, R.; Sibonga, J. D.; Bouxsein, M. L.

2010-01-01

The factor-of-risk (Phi), defined as the ratio of applied load to bone strength, is a biomechanical approach to hip fracture risk assessment that may be used to identify subjects who are at increased risk for fracture. The purpose of this project was to calculate the factor of risk in long duration astronauts after return from a mission on the International Space Station (ISS), which is typically 6 months in duration. The load applied to the hip was calculated for a sideways fall from standing height based on the individual height and weight of the astronauts. The soft tissue thickness overlying the greater trochanter was measured from the DXA whole body scans and used to estimate attenuation of the impact force provided by soft tissues overlying the hip. Femoral strength was estimated from femoral areal bone mineral density (aBMD) measurements by dual-energy x-ray absorptiometry (DXA), which were performed between 5-32 days of landing. All long-duration NASA astronauts from Expedition 1 to 18 were included in this study, where repeat flyers were treated as separate subjects. Male astronauts (n=20) had a significantly higher factor of risk for hip fracture Phi than females (n=5), with preflight values of 0.83+/-0.11 and 0.36+/-0.07, respectively, but there was no significant difference between preflight and postflight Phi (Figure 1). Femoral aBMD measurements were not found to be significantly different between men and women. Three men and no women exceeded the theoretical fracture threshold of Phi=1 immediately postflight, indicating that they would likely suffer a hip fracture if they were to experience a sideways fall with impact to the greater trochanter. These data suggest that male astronauts may be at greater risk for hip fracture than women following spaceflight, primarily due to relatively less soft tissue thickness and subsequently greater impact force.

The fracture sites of atypical femoral fractures are associated with the weight-bearing lower limb alignment.

Science.gov (United States)

Saita, Yoshitomo; Ishijima, Muneaki; Mogami, Atsuhiko; Kubota, Mitsuaki; Baba, Tomonori; Kaketa, Takefumi; Nagao, Masashi; Sakamoto, Yuko; Sakai, Kensuke; Kato, Rui; Nagura, Nana; Miyagawa, Kei; Wada, Tomoki; Liu, Lizu; Obayashi, Osamu; Shitoto, Katsuo; Nozawa, Masahiko; Kajihara, Hajime; Gen, Hogaku; Kaneko, Kazuo

2014-09-01

Atypical femoral fractures (AFFs) are stress-related fractures that are speculated to associate with long-term treatment with bisphosphonates for osteoporosis. A history of AFF is a high risk factor for the development of a subsequent AFF in the same location of the contralateral femur, suggesting that a patient's individual anatomical factor(s) are related to the fracture site of AFFs. In this study, we investigated the radiographs of fourteen AFFs (four bilateral fractures among ten patients) treated at six hospitals associated with our university between 2005 and 2010. The fracture site and standing femorotibial angle (FTA), which reflects the mechanical axis of the lower limb, were measured on weight-bearing lower limb radiographs. The fracture site and FTA of patients with typical femoral fractures (TFF) were compared to those of patients with AFFs. The correlations were examined using Spearman's rank correlation coefficients. The fracture locations in the femora were almost the same in the patients with bilateral AFFs. There was a positive correlation between the fracture site and the standing FTA in the patients with AFFs (r=0.82, 95% confidence interval; 0.49 to 0.94), indicating that the larger the standing FTA (varus alignment), the more distal the site of the fracture in the femur. The FTA of the patients with atypical diaphyseal femoral fracture were significantly larger compared to that of those with not only atypical subtrochanteric fractures but also TFFs. In conclusion, the fracture sites of AFFs are associated with the standing lower limb alignment, while those of TFFs are not. Copyright © 2014 Elsevier Inc. All rights reserved.

Investigations on the influence of the stress state on fracture-mechanical values

International Nuclear Information System (INIS)

Schmidt, P.

1979-01-01

Fracture toughness obtained from specimen can be applied to construction elements only when the same stress state exists. In standardised fracture-mechanical tests plain strain is realised. Using the stress intensity factor, a critical crack length or a critical load can be obtained. Above these values a crack propagates in an unstable way. The specimen are tested under uni-axial load. In this paper investigations have been made whether a biaxial load increases the stress state over the plain strain and whether consequently a decrease of the critical fracture toughness and a shift of the temperatures Tsub(g)sub(y) and Tsub(s) results which characterise the fracture behaviour of steel. In order to answer these questions the tests were made which induced due to their geometry an additional nominal stress parallel to the crack front in spite of uni-axial loading. The results were compared with those from specimen without an additional nominal stress and having in their cross section under same test conditions nearly the same plain strain. The fracture toughness of both specimen types were compared at temperatures between 142 K and 252 K and correlated to other material-characterising values. The tests were completed by stress analysis and by comparing the crack opening displacement. Due to the additional stress, Tsub(g)sub(y) was found to be 20 K higher than for the reference specimen. The fracture toughness decreases significantly in certain temperature ranges. The plastic stress concentration factor was comperatively higher and the remaining plastic crack opening decreases up to 25%. (orig.) [de

Is human fracture hematoma inherently angiogenic?

LENUS (Irish Health Repository)

Street, J

2012-02-03

This study attempts to explain the cellular events characterizing the changes seen in the medullary callus adjacent to the interfragmentary hematoma during the early stages of fracture healing. It also shows that human fracture hematoma contains the angiogenic cytokine vascular endothelial growth factor and has the inherent capability to induce angiogenesis and thus promote revascularization during bone repair. Patients undergoing emergency surgery for isolated bony injury were studied. Raised circulating levels of vascular endothelial growth factor were seen in all injured patients, whereas the fracture hematoma contained significantly higher levels of vascular endothelial growth factor than did plasma from these injured patients. However, incubation of endothelial cells in fracture hematoma supernatant significantly inhibited the in vitro angiogenic parameters of endothelial cell proliferation and microtubule formation. These phenomena are dependent on a local biochemical milieu that does not support cytokinesis. The hematoma potassium concentration is cytotoxic to endothelial cells and osteoblasts. Subcutaneous transplantation of the fracture hematoma into a murine wound model resulted in new blood vessel formation after hematoma resorption. This angiogenic effect is mediated by the significant concentrations of vascular endothelial growth factor found in the hematoma. This study identifies an angiogenic cytokine involved in human fracture healing and shows that fracture hematoma is inherently angiogenic. The differences between the in vitro and in vivo findings may explain the phenomenon of interfragmentary hematoma organization and resorption that precedes fracture revascularization.

Morbidity, mortality, associated injuries, and management of traumatic rib fractures

OpenAIRE

Frank Cheau-Feng Lin; Ruei-Yun Li; Yung-Wei Tung; Kee-Ching Jeng; Stella Chin-Shaw Tsai

2016-01-01

Background: Thoracic trauma is responsible for approximately 25% of trauma deaths, and rib fractures are present in as many as 40–80% of patients, and intensive care and/or ventilator support are frequently required for these patients. To identify their risk factors would improve treatment strategies for these patients. Methods: Between March 2005 and December 2013, consecutive patients with blunt thoracic trauma, who were admitted to the Department of Thoracic Surgery at Tungs' Taichung M...

A fracture mechanics model for iodine stress corrosion crack propagation in Zircaloy tubing

International Nuclear Information System (INIS)

Crescimanno, P.J.; Campbell, W.R.; Goldberg, I.

1984-01-01

A fracture mechanics model is presented for iodine-induced stress corrosion cracking in Zircaloy tubing. The model utilizes a power law to relate crack extension velocity to stress intensity factor, a hyperbolic tangent function for the influence of iodine concentration, and an exponential function for the influence of temperature and material strength. Comparisons of predicted to measured failure times show that predicted times are within a factor of two of the measured times for a majority of the specimens considered

Mathematical algorithm development and parametric studies with the GEOFRAC three-dimensional stochastic model of natural rock fracture systems

Science.gov (United States)

Ivanova, Violeta M.; Sousa, Rita; Murrihy, Brian; Einstein, Herbert H.

2014-06-01

This paper presents results from research conducted at MIT during 2010-2012 on modeling of natural rock fracture systems with the GEOFRAC three-dimensional stochastic model. Following a background summary of discrete fracture network models and a brief introduction of GEOFRAC, the paper provides a thorough description of the newly developed mathematical and computer algorithms for fracture intensity, aperture, and intersection representation, which have been implemented in MATLAB. The new methods optimize, in particular, the representation of fracture intensity in terms of cumulative fracture area per unit volume, P32, via the Poisson-Voronoi Tessellation of planes into polygonal fracture shapes. In addition, fracture apertures now can be represented probabilistically or deterministically whereas the newly implemented intersection algorithms allow for computing discrete pathways of interconnected fractures. In conclusion, results from a statistical parametric study, which was conducted with the enhanced GEOFRAC model and the new MATLAB-based Monte Carlo simulation program FRACSIM, demonstrate how fracture intensity, size, and orientations influence fracture connectivity.

Study on the relationship between stress intensity factor and J integral for mixed mode crack with arbitrary inclination based on SBFEM

International Nuclear Information System (INIS)

Zhu, C L; Li, J B; Lin, G; Zhong, H

2010-01-01

The J integral and the stress intensity factor (SIF) K are both important research objects of fracture mechanics, and are often employed to establish criteria for crackpropagation. The relationship between them has always been a research hotspot. In this paper, the SIF can be obtained conveniently by the scaled boundary finite element method (SBFEM) due to the fact that analytical solution can be obtained along the radial direction for stress singularity problems. The J integral can be solved analytically using the formulae between J and K for mixed mode crack with arbitrary inclination in elastic materials. Moreover, the J integral values obtained by this method are more accurate and convenient than by its definition. Factors that affect the accuracy of SIF and J integral, such as the distance between the crack and outer boundary, size of the discretized elements and partition of the domain into super-elements, are examined.

Associations of early premenopausal fractures with subsequent fractures vary by sites and mechanisms of fractures.

Science.gov (United States)

Honkanen, R; Tuppurainen, M; Kroger, H; Alhava, E; Puntila, E

1997-04-01

In a retrospective population-based study we assessed whether and how self-reported former fractures sustained at the ages of 20-34 are associated with subsequent fractures sustained at the ages of 35-57. The 12,162 women who responded to fracture questions of the baseline postal enquiry (in 1989) of the Kuopio Osteoporosis Study, Finland formed the study population. They reported 589 former and 2092 subsequent fractures. The hazard ratio (HR), with 95% confidence interval (CI), of a subsequent fracture was 1.9 (1.6-2.3) in women with the history of a former fracture compared with women without such a history. A former low-energy wrist fracture was related to subsequent low-energy wrist [HR = 3.7 (2.0-6.8)] and high-energy nonwrist [HR = 2.4 (1.3-4.4)] fractures, whereas former high-energy nonwrist fractures were related only to subsequent high-energy nonwrist [HR = 2.8 (1.9-4.1)] but not to low-energy wrist [HR = 0.7 (0.3-1.8)] fractures. The analysis of bone mineral density (BMD) data of a subsample of premenopausal women who underwent dual x-ray absorptiometry (DXA) during 1989-91 revealed that those with a wrist fracture due to a fall on the same level at the age of 20-34 recorded 6.5% lower spinal (P = 0.140) and 10.5% lower femoral (P = 0.026) BMD than nonfractured women, whereas the corresponding differences for women with a former nonwrist fracture due to high-energy trauma were -1.8% (P = 0.721) and -2.4% (P = 0. 616), respectively. Our results suggest that an early premenopausal, low-energy wrist fracture is an indicator of low peak BMD which predisposes to subsequent fractures in general, whereas early high-energy fractures are mainly indicators of other and more specific extraskeletal factors which mainly predispose to same types of subsequent fractures only.

Time to first fracture affects sweetness of gels

NARCIS (Netherlands)

Sala, G.; Stieger, M.A.

2013-01-01

The aim of this study was to investigate the influence of the breakdown behaviour on sweetness intensity of gelled model foods. Emulsion-filled gelatine/agar gels varying mainly in fracture strain (eF) were used. The fracture strain was modified by changing either the ratio between gelatine and agar

Obesity and fracture risk

OpenAIRE

Gonnelli, Stefano; Caffarelli, Carla; Nuti, Ranuccio

2014-01-01

Obesity and osteoporosis are two common diseases with an increasing prevalence and a high impact on morbidity and mortality. Obese women have always been considered protected against osteoporosis and osteoporotic fractures. However, several recent studies have challenged the widespread belief that obesity is protective against fracture and have suggested that obesity is a risk factor for certain fractures.

Effects of " vitex agnus castus" extract and magnesium supplementation, alone and in combination, on osteogenic and angiogenic factors and fracture healing in women with long bone fracture

OpenAIRE

Mohammad Hassan Eftekhari; Zahra Hassanzadeh Rostami; Mohammad Jafar Emami; Hamid Reza Tabatabaee

2014-01-01

Background: The purpose of this study was to investigate the effects of the combination of vitex agnus castus extract, as a source of phytoestrogens, plus magnesium supplementation on osteogenic and angiogenic factors and callus formation in women with long bone fracture. Material and Methods: In a double-blind randomized placebo controlled trial, 64 women with long bone fracture, 20-45 years old, were randomly allocated to receive 1) one Agnugol tablet (4 mg dried fruit extract of vitex agnu...

Numerical estimate of fracture parameters under elastic and elastic-plastic conditions

International Nuclear Information System (INIS)

Soba, Alejandro; Denis, Alicia C.

2003-01-01

The importance of the stress intensity factor K in the elastic fracture analysis is well known. In this work three methods are developed to estimate the parameter K I , corresponding to the normal loading mode, employing the finite elements method. The elastic-plastic condition is also analyzed, where the line integral J is the relevant parameter. Two cases of interest are studied: sample with a crack in its center and tubes with internal pressure. (author)

A comparative study on the influential factors of China's provincial energy intensity

International Nuclear Information System (INIS)

Yang, Guangfei; Li, Wenli; Wang, Jianliang; Zhang, Dongqing

2016-01-01

China has become the largest energy consumer worldwide, and it is important to study the energy intensity to realize the sustainable development goal of China. This paper focuses on investigating the influential factors of China's energy intensity using provincial-level panel data from 1985 to 2012. More specifically, we try to identify which factor is relatively more important to pay attention to. A novel approach based on evolutionary computation is proposed to intelligently mine the intrinsic relations between observed phenomena and to let the important factors automatically emerge from the discovered nonlinear models. However, due to China's vast territory and significant heterogeneities, this approach may fail to examine some detailed or hidden information when analyzing the country as a whole. Instead, we concentrate on the provincial level because the provinces play vital roles in reducing energy intensity in China. From our analytical results, the main findings are as follows: (1) the Total Population is the most important influential factor across China's provinces, while the Energy Price Index has the least impact; and (2) the provinces could be naturally classified into four categories based on the primary factors emerged from data, and such classification could reveal more about the true underlying features of each area. - Highlights: • Identify the important factors of China's energy intensity by symbolic regression. • Analyze China's energy intensity using provincial-level panel data from 1985 to 2012. • Intelligently investigate nonlinear models and the emergence of important factors. • The Total Population is discovered to be the most important influential factor. • Provinces are naturally classified into four categories by the influential factors.

Transient Stress Intensity Factors of Functionally Graded Hollow Cylinders with Internal Circumferential Cracks

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Iman Eshraghi

Full Text Available Abstract In this paper, transient thermomechanical stress intensity factors for functionally graded cylinders with complete internal circumferential cracks are obtained using the weight function method. The finite difference method is used to calculate the time dependent temperature distribution and thermal stresses along the cylinder thickness. Furthermore, finite element analysis is performed to determine the weight function coefficients and to investigate the accuracy of the predicted stress intensity factors from the weight functions. Variation of the stress intensity factors with time and effects of the material gradation on the results are investigated, as well. It is shown that the proposed technique can be used to accurately predict transient thermomechanical stress intensity factors for functionally graded cylinders with arbitrary material gradation.

Low-energy extracorporeal shockwave therapy (ESWT improves metaphyseal fracture healing in an osteoporotic rat model.

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Gina A Mackert

Full Text Available As result of the current demographic changes, osteoporosis and osteoporotic fractures are becoming an increasing social and economic burden. In this experimental study, extracorporeal shock wave therapy (ESWT, was evaluated as a treatment option for the improvement of osteoporotic fracture healing.A well-established fracture model in the metaphyseal tibia in the osteoporotic rat was used. 132 animals were divided into 11 groups, with 12 animals each, consisting of one sham-operated group and 10 ovariectomized (osteoporotic groups, of which 9 received ESWT treatment. Different energy flux intensities (0.15 mJ/mm2, 0.35 mJ/mm2, or 0.55 mJ/mm2 as well as different numbers of ESWT applications (once, three times, or five times throughout the 35-day healing period were applied to the osteoporotic fractures. Fracture healing was investigated quantitatively and qualitatively using micro-CT imaging, quantitative real-time polymerase chain reaction (qRT-PCR analysis, histomorphometric analysis and biomechanical analysis.The results of this study show a qualitative and quantitative improvement in the osteoporotic fracture healing under low-energy (energy flux intensity: 0,15 mJ/mm2 ESWT and with fewer treatment applications per healing period.In conclusion, low-energy ESWT seems to exhibit a beneficial effect on the healing of osteoporotic fractures, leading to improved biomechanical properties, enhanced callus-quantity and -quality, and an increase in the expression of bone specific transcription factors. The results suggest that low-energy ESWT, as main treatment or as adjunctive treatment in addition to a surgical intervention, may prove to be an effective, simple to use, and cost-efficient option for the qualitative and quantitative improvement of osteoporotic fracture healing.

Stress intensity factors for complete internal and external cracks in spherical shells

International Nuclear Information System (INIS)

Chao, Y.J.; Chen, H.

1989-01-01

Cracks or flows found in the nuclear structure must be fully evaluated to assure the safety of the plant. The weight function method has been widely used in the determination of stress intensity factors for cracks under stress gradient e.g. for thermal shock loading. The unique features of the weight function method is that once the weight function for a particular cracked geometry is determined the stress intensity factors at the crack tip for any loading applied to the flawed structure can be calculated by a simple integration. In this paper the stress intensity factors of the complete, part-through internal and external cracks in a spherical shell are determined. The finite element method was used to develop the weight functions for the flawed geometry. The approximate crack surface profile was used to derive the weight functions. The stress intensity factors associated with the cracks in spherical shells under internal pressure are determined by both the weight functions and the direct finite element method

Fracture behaviour of heat cured fly ash based geopolymer concrete

International Nuclear Information System (INIS)

Sarker, Prabir K.; Haque, Rashedul; Ramgolam, Karamchand V.

2013-01-01

Highlights: ► Fly ash geopolymer (GPC) can help reduce carbon footprint of concrete. ► Fracture behaviour of GPC as compared to OPC concrete was studied. ► Fracture energy of GPC was similar to that of OPC concrete. ► GPC showed higher fracture toughness than OPC concrete. ► Higher bond strength resulted in higher crack resistance of GPC. -- Abstract: Use of fly ash based geopolymer as an alternative binder can help reduce CO 2 emission of concrete. The binder of geopolymer concrete (GPC) is different from that of ordinary Portland cement (OPC) concrete. Thus, it is necessary to study the effects of the geopolymer binder on the behaviour of concrete. In this study, the effect of the geopolymer binder on fracture characteristics of concrete has been investigated by three point bending test of RILEM TC 50 – FMC type notched beam specimens. The peak load was generally higher in the GPC specimens than the OPC concrete specimens of similar compressive strength. The failure modes of the GPC specimens were found to be more brittle with relatively smooth fracture planes as compared to the OPC concrete specimens. The post-peak parts of the load–deflection curves of GPC specimens were steeper than that of OPC concrete specimens. Fracture energy calculated by the work of fracture method was found to be similar in both types of concrete. Available equations for fracture energy of OPC concrete yielded conservative estimations of fracture energy of GPC. The critical stress intensity factor of GPC was found to be higher than that of OPC concrete. The different fracture behaviour of GPC is mainly because of its higher tensile strength and bond strength than OPC concrete of the same compressive strength.

Risk Factors for the Failure of Spinal Burst Fractures Treated Conservatively According to the Thoracolumbar Injury Classification and Severity Score (TLICS: A Retrospective Cohort Trial.

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Jieliang Shen

Full Text Available The management of thoracolumbar (TL burst fractures is still controversial. The thoracolumbar injury classification and severity score (TLICS algorithm is now widely used to guide clinical decision making, however, in clinical practice, we come to realize that TLICS also has its limitations for treating patients with total scores less than 4, for which conservative treatment may not be optimal in all cases.The aim of this study is to identify several risk factors for the failure of conservative treatment of TL burst fractures according to TLICS algorithm.From June 2008 to December 2013, a cohort of 129 patients with T10-l2 TL burst fractures with a TLISC score ≤3 treated non-operatively were identified and included into this retrospective study. Age, sex, pain intensity, interpedicular distance (IPD, canal compromise, loss of vertebral body height and kyphotic angle (KA were selected as potential risk factors and compared between the non-operative success group and the non-operative failure group.One hundred and four patients successfully completed non-operative treatment, the other 25 patients were converted to surgical treatment because of persistent local back pain or progressive neurological deficits during follow-up. Our results showed that age, visual analogue scale (VAS score and IPD, KA were significantly different between the two groups. Furthermore, regression analysis indicated that VAS score and IPD could be considered as significant predictors for the failure of conservative treatment.The recommendation of non-operative treatment for TLICS score ≤3 has limitations in some patients, and VAS score and IPD could be considered as risk factors for the failure of conservative treatment. Thus, conservative treatment should be decided with caution in patients with greater VAS scores or IPD. If non-operative management is decided, a close follow-up is necessary.

Sedimentological and Stratigraphic Controls on Natural Fracture Distribution in Wajid Group, SW Saudi Arabia

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Benaafi, Mohammed; Hariri, Mustafa; Abdullatif, Osman; Makkawi, Mohammed; Korvin, Gabor

2016-04-01

The Cambro-Permian Wajid Group, SW Saudi Arabia, is the main groundwater aquifer in Wadi Al-Dawasir and Najran areas. In addition, it has a reservoir potentiality for oil and natural gas in Rub' Al-Khali Basin. Wajid Group divided into four formations, ascending Dibsiyah, Sanamah, Khussyayan and Juwayl. They are mainly sandstone and exposed in an area extend from Wadi Al-Dawasir southward to Najran city and deposited within fluvial, shallow marine and glacial environments. This study aims to investigate the sedimentological and stratigraphic controls on the distribution of natural fractures within Wajid Group outcrops. A scanline sampling method was used to study the natural fracture network within Wajid Group outcrops, where the natural fractures were measured and characterized in 12 locations. Four regional natural fracture sets were observed with mean strikes of 050o, 075o, 345o, and 320o. Seven lithofacies characterized the Wajid Group at these locations and include fine-grained sandstone, coarse to pebbly sandstone, cross-bedded sandstone, massive sandstone, bioturbated sandstone, conglomerate sandstone, and conglomerate lithofacies. We found that the fine-grained and small scale cross-bedded sandstones lithofacies are characterized by high fracture intensity. In contrast, the coarse-grained sandstone and conglomerate lithofacies have low fracture intensity. Therefore, the relative fracture intensity and spacing of natural fractures within Wajid Group in the subsurface can be predicted by using the lithofacies and their depositional environments. In terms of stratigraphy, we found that the bed thickness and the stratigraphic architecture are the main controls on fractures intensity. The outcomes of this study can help to understand and predict the natural fracture distribution within the subsurface fractured sandstone hosting groundwater and hydrocarbon in Wajid and Rub' Al-Khali Basins. Hence, the finding of this study might help to explore and develop the

Facial Fractures.

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Ghosh, Rajarshi; Gopalkrishnan, Kulandaswamy

2018-06-01

The aim of this study is to retrospectively analyze the incidence of facial fractures along with age, gender predilection, etiology, commonest site, associated dental injuries, and any complications of patients operated in Craniofacial Unit of SDM College of Dental Sciences and Hospital. This retrospective study was conducted at the Department of OMFS, SDM College of Dental Sciences, Dharwad from January 2003 to December 2013. Data were recorded for the cause of injury, age and gender distribution, frequency and type of injury, localization and frequency of soft tissue injuries, dentoalveolar trauma, facial bone fractures, complications, concomitant injuries, and different treatment protocols.All the data were analyzed using statistical analysis that is chi-squared test. A total of 1146 patients reported at our unit with facial fractures during these 10 years. Males accounted for a higher frequency of facial fractures (88.8%). Mandible was the commonest bone to be fractured among all the facial bones (71.2%). Maxillary central incisors were the most common teeth to be injured (33.8%) and avulsion was the most common type of injury (44.6%). Commonest postoperative complication was plate infection (11%) leading to plate removal. Other injuries associated with facial fractures were rib fractures, head injuries, upper and lower limb fractures, etc., among these rib fractures were seen most frequently (21.6%). This study was performed to compare the different etiologic factors leading to diverse facial fracture patterns. By statistical analysis of this record the authors come to know about the relationship of facial fractures with gender, age, associated comorbidities, etc.

A New Displacement-based Approach to Calculate Stress Intensity Factors With the Boundary Element Method

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Marco Gonzalez

Full Text Available Abstract The analysis of cracked brittle mechanical components considering linear elastic fracture mechanics is usually reduced to the evaluation of stress intensity factors (SIFs. The SIF calculation can be carried out experimentally, theoretically or numerically. Each methodology has its own advantages but the use of numerical methods has become very popular. Several schemes for numerical SIF calculations have been developed, the J-integral method being one of the most widely used because of its energy-like formulation. Additionally, some variations of the J-integral method, such as displacement-based methods, are also becoming popular due to their simplicity. In this work, a simple displacement-based scheme is proposed to calculate SIFs, and its performance is compared with contour integrals. These schemes are all implemented with the Boundary Element Method (BEM in order to exploit its advantages in crack growth modelling. Some simple examples are solved with the BEM and the calculated SIF values are compared against available solutions, showing good agreement between the different schemes.

[The role of malnutrition and other medical factors in the evolution of patients with hip fracture].

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García Lázaro, M; Montero Pérez-Barquero, M; Carpintero Benítez, P

2004-11-01

As the population progressively ages, hip fractures have become increasingly common and are associated with high morbidity and mortality and a pronounced decline in functional status. Hip fractures frequently occur in elderly patients with a high rate of comorbidity and polymedication. Patients hospitalised with hip fractures often display signs of protein malnutrition and may develop medical complications requiring intrahospital care. These factors, more than simply surgical ones, unfavourably influence the vital status and functional outcome of these patients. For this reason, it is necessary to improve the management of pre-existing conditions during hospitalisation, assess and treat malnutrition and prevent medical complications to achieve optimal outcomes for these patients. With this objective, we believe that care should be provided by multidisciplinary teams in close partnership with internists.

[Stress fractures in disabled athletes' preparation for the paralympic games in Athens, 2004: an assessment].

Science.gov (United States)

Laboute, E; Druvert, J C; Pailler, D; Piera, J-B

2008-03-01

To identify stress fracture frequency and the associated risk factors in disabled female athletes preparing the Paralympic Games in Athens in 2004. The study is focused on four athletes (including one with a vision impairment) among the 31 women selected to participate in the Paralympic Games. The medical records of selected athletes not having been able to participate in the Games due to a stress fracture were analyzed. One case of stress fracture to the first metatarsal was reported of one below-knee amputee and an additional case to the second metatarsal of one hemiplegic athlete. Two of three athletes with physical disability were unable to participate in the Games because of stress fracture occurring during the preparatory phase. Among four athletes selected to take part in the Paralympic Games. If morphological predispositions are inherent to the sportswomen, the main favouring factor to be retained is their running asymmetry. Training programmes must therefore take this characteristic into account and must not offer heavy-load repetitive exercise (such as endurance or jogging) at the expense of technique. Over-intense training exposes the disabled athlete to this type of pathology and is likely to affect his chances of competing.

The vascular and neurogenic factors associated with erectile dysfunction in patients after pelvic fractures

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Yong Guan

2015-10-01

Full Text Available ABSTRACT Erectile dysfunction (ED is a common complication of pelvic fractures. To identify the vascular and neurogenic factors associated with ED, 120 patients admitted with ED after traumatic pelvic fracture between January 2009 and June 2013 were enrolled in this study. All patients answered the International Index of Erectile Function (IIEF-5 questionnaire. Nocturnal penile tumescence (NPT testing confirmed the occurrence of ED in 96 (80% patients on whom penile duplex ultrasound and neurophysiological testing were further performed. Of these ED patients 29 (30% were demonstrated only with vascular abnormality, 41 (42.7% were detected only with neural abnormality, 26 (27.1% revealed mixed abnormalities. Of the 55 patients (29+26 with vascular problems, 7 patients (12.7% with abnormal arterial response to intracavernous injection of Bimix (15mg papaverine and 1mg phentolamine, 31 (56.4% with corporal veno-occlusive dysfunction and 17 (30.9% had both problems. Of the 67 (41+26 patients with abnormal neurophysiological outcomes, 51 (76.1% with abnormal bulbocavernosus reflex (BCR, 20 (29.9% with pathological pudendal nerve evoked potentials (PDEPs and 25 (37.3% with abnormal posterior tibial somatosensory nerve evoked potentials (PTSSEPs. Our observation indicated that neurogenic factors are important for the generation of ED in patients with pelvic fracture; venous impotence is more common than arteriogenic ED.

Effects of cold working ratio and stress intensity factor on intergranular stress corrosion cracking susceptibility of non-sensitized austenitic stainless steels in simulated BWR and PWR primary water

International Nuclear Information System (INIS)

Yaguchi, Seiji; Yonezawa, Toshio

2012-01-01

To evaluate the effects of cold working ratio, stress intensity factor and water chemistry on an IGSCC susceptibility of non-sensitized austenitic stainless steel, constant displacement DCB specimens were applied to SCC tests in simulated BWR and PWR primary water for the three types of austenitic stainless steels, Types 316L, 347 and 321. IGSCC was observed on the test specimens in simulated BWR and PWR primary water. The observed IGSCC was categorized into the following two types. The one is that the IGSCC observed on the same plane of the pre-fatigue crack plane, and the other is that the IGSCC observed on a plane perpendicular to the pre-fatigue crack plane. The later IGSCC fractured plane is parallel to the rolling plane of a cold rolled material. Two types of IGSCC fractured planes were changed according to the combination of the testing conditions (cold working ratio, stress intensity factor and simulated water). It seems to suggest that the most susceptible plane due to fabrication process of materials might play a significant role of IGSCC for non-sensitized cold worked austenitic stainless steels, especially, in simulated PWR primary water. Based upon evaluating on the reference crack growth rate (R-CGR) of the test specimens, the R-CGR seems to be mainly affected by cold working ratio. In case of simulated PWR primary water, it seems that the effect of metallurgical aspects dominates IGSCC susceptibility. (author)

Fall with and without fracture in elderly: what's different?

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Kantayaporn, Choochat

2012-10-01

Falling fracture was one of the health problems in elderly. This presentation aimed to identify the factors of fall that caused fractures. The retrospective case-control study was designed. Samples were all who experienced fall within 1 year in Lamphun. Factors included age, gender underlying diseases, chronic drugs used, history of parent fragility fracture, age of menopause, steroid used, body mass index, visual acuity and time up and go test were studied. Multivariate regression analysis was used. 336 cases of fractures in 1,244 cases of fall were found. Significant factors of falling fracture group that were different from fall without fracture group included age, female gender, menopause before age of 45 and visual impairment. Visual impairment was the other key factor rather than osteoporosis that caused fall with fracture. The author suggested that falling fracture prevention programs should be included correction of visual impairment other than osteoporosis treatment.

Vertebral Fractures and Spondylosis in Men - Original Investigation

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Selmin Gülbahar

2008-04-01

Full Text Available Aim: The aim of this study was to investigate the relationship between vertebral fractures and spondylosis and bone mineral density in men older than 60 years. Material and Method: Thirty-two men with back and low back pain aged over 60 years were included into the study. Thoracic and lumbar spine radiographs were taken and, anterior, central and posterior heights of each vertebral body from T4 to L5 was measured and than the number of vertebral fractures was assessed. Osteophyte and disc scores were used for evaluation of spondylosis. Bone mineral density was measured by dual-energy-X-ray absorptiometry. Measurements were obtained from lumbar vertebrae and proximal femoral region. Results: Significant positive correlations were found between vertebral fracture and osteophyte score and bone mineral density of total femoral region. When osteophyte score and total femoral bone mineral density were taken into consideration, there were no significant correlations between other parameters and vertebral fracture. Significant positive correlations were observed between osteophyte score and bone mineral density and t scores of L1-4. Also there were significant positive correlations between disc score and both bone mineral density and t scores of L1-4. Significant positive correlation was also found between femoral bone density and body weight. Conclusion: Finally, lumbar bone mineral density increases with spinal degenerative changes, but the increase in bone mineral density can not prevent sub clinic vertebral fractures. Especially, in the men who have intensive spinal degenerative changes, the measurement of lumbar bone mineral density is not enough for determining the fracture risk. Measurement of femoral bone mineral density and evaluation of clinic risk factors are more important for determining the fracture risk. (From the World of Osteoporosis 2008;14:1-6

Epidemiology of rib fractures in older men: Osteoporotic Fractures in Men (MrOS) prospective cohort study.

Science.gov (United States)

Barrett-Connor, Elizabeth; Nielson, Carrie M; Orwoll, Eric; Bauer, Douglas C; Cauley, Jane A

2010-03-15

To study the causes and consequences of radiologically confirmed rib fractures (seldom considered in the context of osteoporosis) in community dwelling older men. Prospective cohort study (Osteoporotic Fractures in Men (MrOS) Study). 5995 men aged 65 or over recruited in 2000-2 from six US sites; 99% answered mailed questionnaires about falls and fractures every four months for a mean 6.2 (SD 1.3) year follow-up. New fractures validated by radiology reports; multivariate Cox proportional hazard ratios were used to evaluate factors independently associated with time to incident rib fracture; associations between baseline rib fracture and incident hip and wrist fracture were also evaluated. The incidence of rib fracture was 3.5/1000 person years, and 24% (126/522) of all incident non-spine fractures were rib fractures. Nearly half of new rib fractures (48%; n=61) followed falling from standing height or lower. Independent risk factors for an incident rib fracture were age 80 or above, low bone density, difficulty with instrumental activities of daily living, and a baseline history of rib/chest fracture. Men with a history of rib/chest fracture had at least a twofold increased risk of an incident rib fracture (adjusted hazard ratio 2.71, 95% confidence interval 1.86 to 3.95), hip fracture (2.05, 1.33 to 3.15), and wrist fracture (2.06, 1.14 to 3.70). Only 14/82 of men reported being treated with bone specific drugs after their incident rib fracture. Rib fracture, the most common incident clinical fracture in men, was associated with classic risk markers for osteoporosis, including old age, low hip bone mineral density, and history of fracture. A history of rib fracture predicted a more than twofold increased risk of future fracture of the rib, hip, or wrist, independent of bone density and other covariates. Rib fractures should be considered to be osteoporotic fractures in the evaluation of older men for treatment to prevent future fracture.

Predisposing Risk Factors and Stress Fractures in Division I Cross Country Runners.

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Giffin, Kaci L; Knight, Kathy B; Bass, Martha A; Valliant, Melinda W

2017-11-11

The purpose of this study was to explore factors associated with increased stress fractures in collegiate cross country runners. Participants in this study were 42 male and female cross country runners at a Division I university. Each athlete completed a questionnaire regarding smoking status, vitamin/mineral intake, previous stress fracture history, birth control usage, menstrual status, and demographic information. Nutritional assessment via a 3-day food record and measurements of whole body, lumbar spine, and hip bone mineral densities (BMD) were also conducted on each athlete. Results indicated that 40% of the female and 35% of the male runners reported a history of stress fracture, and that all of these did not meet the recommended daily energy intake or adequate intakes for calcium or Vitamin D required for their amount of training. Two-tailed t-test found statistically higher incidences of lumbar spine BMD in males and females whose daily calcium and Vitamin D intakes were below minimum requirements as well as for women whose caloric intake was below the required level. When data on the lumbar spine was evaluated, 31% of participants (31.8% of the male and 30% of the female runners) were identified as having osteopenia and 4.8% with osteoporosis. Results warrant a need for future longitudinal studies.

[Factors affecting the recovery in the intensive care unit].

Science.gov (United States)

Turkov, P N; Nikitin, V V; Antsupova, M A; Podkopaev, V N; Panfilova, R P; Ivanova, I N; Nesterova, L I

2013-01-01

Urgency of the problem is defined by economical, regulatory and legislative acts, regional social and moral factors. There is critical situation in Russian Pediatric Healthcare system. This situation is due to inadequate funding, high medical technologies inaccessibility for some Russian children, their adverse health state. The article presents a retrospective analysis of intensive therapy and resuscitation outcomes with technical equipment and work environment assessment in the intensive care unit of Tushinskaya city pediatric clinic for the period from 2007 to 2011. Anaesthetic and emergency care quality and safety depend on several factors: permanent equipment improvement, comprehensive analysis of every fatal case and full implementation of "Anti-epidemic (prophylactic) actions plan" and "Program of monitoring compliance with the sanitary norms".

Low-intensity pulsed ultrasound: Nonunions

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Dijkman Bernadette

2009-01-01

Full Text Available Nonunions occur in 5-10% of fractures and are characterized by the failure to heal without further intervention. Low intensity pulsed ultrasound therapy has been developed as an alternative to surgery in the treatment of nonunions. We describe a systematic review on trials of low-intensity pulsed ultrasound therapy for healing of nonunions. We searched the electronic databases Medline and the Cochrane library for articles on ultrasound and healing of nonunions published up to 2008. Trials selected for the review met the following criteria: treatment of at least one intervention group with low intensity pulsed ultrasound; inclusion of patients (humans with one or more nonunions (defined as "established" or as a failure to heal for a minimum of eight months after initial injury; and assessment of healing and time to healing, as determined radiographically. The following data were abstracted from the included studies: sample size, ultrasound treatment characteristics, nonunion location, healing rate, time to fracture healing, fracture age, and demographic information. We found 79 potentially eligible publications, of which 14 met our inclusion criteria. Of these, eight studies were used for data abstraction. Healing rates averaged 87%, (range 65.6%-100% among eight trials. Mean time to healing was 146.5 days, (range 56-219 days. There is evidence from trials that low-intensity pulsed ultrasound may be an effective treatment for healing of nonunions. More homogeneous and larger controlled series are needed to further investigate its efficacy.

Perioperative factors affecting the occurrence of acute complex regional pain syndrome following limb bone fracture surgery: data from the Japanese Diagnosis Procedure Combination database.

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Sumitani, Masahiko; Yasunaga, Hideo; Uchida, Kanji; Horiguchi, Hiromasa; Nakamura, Masaya; Ohe, Kazuhiko; Fushimi, Kiyohide; Matsuda, Shinya; Yamada, Yoshitsugu

2014-07-01

Complex regional pain syndrome (CRPS) describes a broad spectrum of symptoms that predominantly localize to the extremities. Although limb fracture is one of the most frequently reported triggering events, few large-scale studies have shown the occurrence of and factors associated with CRPS following limb fracture. This study aimed to show the occurrence and identify of those factors. Using the Japanese Diagnosis Procedure Combination database, we identified 39 patients diagnosed with CRPS immediately after open reduction and internal fixation (ORIF) for limb fracture from a cohort of 185 378 inpatients treated with ORIF between 1 July and 31 December of each year between 2007 and 2010. Patient and clinical characteristics such as age, gender, fracture site, duration of anaesthesia and use of regional anaesthesia were investigated by logistic regression analyses to examine associations between these factors and the in-hospital occurrence of CRPS after ORIF. The occurrence of CRPS was relatively high in fractures of the distal forearm, but low in fractures of the lower limb and in patients with multiple fractures. Generally females are considered to be at high risk of CRPS; however, we found a comparable number of male and female patients suffering from CRPS after ORIF for limb fracture. In terms of perioperative factors, a longer duration of anaesthesia, but not regional anaesthesia, was significantly associated with a higher incidence of CRPS. Although a limited number of CRPS patients were analysed in this study, reduced operative time might help to prevent the development of acute CRPS following limb fracture. © The Author 2013. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Analysis of stress intensity factors for a new mechanical corrosion specimen

International Nuclear Information System (INIS)

Rassineux, B.; Crouzet, D.; Le Hong, S.

1996-03-01

Electricite de France is conducting a research program to determine corrosion cracking rates in the steam generators Alloy 600 tubes of the primary system. The objective is to correlate the cracking rates with the specimen stress intensity factor K I . One of the samples selected for the purpose of this study is the longitudinal notched specimen TEL (TEL: ''Tubulaire a Entailles Longitudinales''). This paper presents the analysis of the stress intensity factor and its experimental validation. The stress intensity factor has been evaluated for different loads using 3D finite element calculations with the Hellen-Parks and G(θ) methods. Both crack initiation and propagation are considered. As an assessment of the method, the numerical simulations are in good agreement with the fatigue crack growth rates measured experimentally for TEL and compact tension (CT) specimens. (authors). 8 refs., 6 figs., 2 tabs

Fracture Risk Assessment in Chronic Kidney Disease, Prospective Testing Under Real World Environments (FRACTURE: a prospective study

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West Sarah L

2010-08-01

Full Text Available Abstract Background Chronic kidney disease (CKD is associated with an increased risk of fracture. Decreased bone mass and disruption of microarchitecture occur early in the course of CKD and worsens with the progressive decline in renal function so that at the time of initiation of dialysis at least 50% of patients have had a fracture. Despite the excess fracture risk, and the associated increases in morbidity and mortality, little is known about the factors that are associated with an increase in fracture risk. Our study aims to identify prognostic factors for bone loss and fractures in patients with stages 3 to 5 CKD. Methods This prospective study aims to enroll two hundred and sixty men and women with stages 3 to 5 CKD. Subjects will be followed for 24 months and we will examine the ability of: 1 bone mineral density by dual x-ray absorptiometry at the spine, hip, and radius; 2 volumetric bone density by high resolution peripheral quantitated computed tomography at the radius and tibia; 3 serum markers of bone turnover; 4 bone formation rate by bone biopsy; and 5 muscle strength and balance to predict spine and non-spine fractures, identified by self-report and/or vertebral morphometry. All measurements will be obtained at baseline, at 12 and at 24 months with the exception of bone biopsy, which will be measured once at 12 months. Subjects will be contacted every 4 months to determine if there have been incident fractures or falls. Discussion This study is one of the first that aims to identify risk factors for fracture in early stage CKD patients. Ultimately, by identifying risk factors for fracture and targeting treatments in this group-before the initiation of renal replacement therapy - we will reduce the burden of disease due to fractures among patients with CKD.

Fracture resistance of teeth restored with packable and hybrid composites

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Ghavam M

2006-06-01

Full Text Available Background and Aim: With recent introduction of packable composites, it is claimed that they apply less stress on tooth structure because of reduced polymerization shrinkage, and similarity of coefficient of thermal expansion to tooth structure. However, the high viscosity may in turn cause less adaptation, so it is not clearly known whether these materials strengthen tooth structure or not. The aim of this study was to evaluate fracture resistance of maxillary premolars, receiving hybrid or packable composite restorations with different methods of application and curing. Materials and Methods: In this experimental study, seventy five intact premolars were randomly assigned to five groups of 15 teeth each. One group was maintained intact as the control group. Similar MOD cavities were prepared in the other teeth. The teeth in group two were restored with Spectrum in incremental layers and light cured with 500 mw/cm2 intensity. The third group were filled with Surefil and cured with light intensity of 500 mw/cm2. The groups four and five were restored with Surefil in bulk technique with two different modes: 500 mw/cm2 intensity and a ramp mode (100-900 mw/cm2 respectively. After thermocycling, force to fracture was assessed and degree of conversion (DC at the bottom of cavities was evaluated for different modes and methods. The curing and placement methods in groups tested for DC (A to D were the same as fracture resistance groups (2 to 5. Data were analyzed using one way ANOVA and Tukey HSD tests with p<0.05 as the limit of significance. Results: All the restored groups showed significantly less fracture resistance than the control group, but had no significant difference among themselves. DC of Spectrum was higher than Surefil. Bulk method with 500 mw/cm2 light intensity, significantly decreased DC. DC in bulk method with high light intensity was not significantly different from incremental method with 500 mw/cm2 light intensity. Conclusion

Predictive factors determining outcomes in pulseless limb in paediatric supracondylar fractures of humerus.

Science.gov (United States)

Chaturvedi, Hemant; Khanna, Vikram; Bhargava, Rakesh; Vaishya, Raju

2018-03-01

Amongst all the complications associated with paediatric supracondylar humerus fractures, significant vascular injury is reported in only 1% cases, of which, less than 1% develop Volkmann's ischemic contracture. This study evaluates factors, like delay in presentation of the injury, limb perfusion and pulse, in determining functional outcome in a supracondylar humerus fractures with pulseless limb. Twenty-one paediatric patients with a pulseless supracondylar humerus fracture presenting from 2012 to 2014 were included. The patients were divided into 3 groups with Group A (pulse returned post-reduction, n = 13), Group B (pink pulseless hand, n = 7) and Group C (white pulseless hand, n = 1). 11 patients in group A and 4 patients in Group B presented within 6 h. of injury while the remaining patients presented after 6 h. The primary outcome was vascular status as indicated by radial pulse and perfusion, and secondary outcomes included functional parameters assessed with Mayo Elbow Performance Score and Flynn criteria. Mean peripheral SpO2 in Group A patients was higher than Group B and Group C had a non-recordable oxygen saturation. Mean capillary refill time was more in Group A than Group B whereas in Group C patient had blanching and no capillary refill was seen. Mean Mayo Elbow Performance Score of Group A patients was highest as compared to Group B and Group C. Patients presenting within 6 h. of injury had a higher mean Mayo Elbow Performance score as compared to the patients presenting after 6 h of injury. Functional outcome as measured by Flynn Criteria was excellent in 13 patients. 6 patients had a good, 2 had fair outcome. A moderate negative corrélation (R = -0.5798) was seen between the time elapsed from the injury and the Mayo Elbow Performance score. Duration to presentation since injury, limb perfusion and presence of peripheral pulses seem to be important predictive factors determining the outcomes in pulseless supracondylar fracture humerus.

Factores de riesgo para osteoporosis y fracturas de cadera: Análisis multivariado Association between hip fractures and risk factors for osteoporosis: Multivariate analysis

Directory of Open Access Journals (Sweden)

Ana Masoni

2007-10-01

Full Text Available En este trabajo se analizó la asociación entre factores de riesgo (FR y fracturas de cadera, se evaluó la influencia de FR relacionados con baja masa ósea o con traumatismos, y se exploró la existencia de factores protectores (FP. Se estudiaron datos de 376 pacientes hospitalizados, de los cuales 151 presentaban fracturas de cadera osteoporóticas (casos; el resto fueron controles, a partir de historias clínicas y un cuestionario sobre FR para osteoporosis. La edad promedio fue 80.6 ± 8.1 años, similar en casos y controles; la relación mujer/varón fue de 3:1 en ambos grupos. Las mujeres fracturadas eran mayores que los varones fracturados (82.5 ± 8.1 versus 79.7 ± 7.2 años; p In this observational, case-control study, 376 inpatients were evaluated in order to determine the association of risk factors (RF and hip fracture; 151 patients had osteoporotic hip fracture (cases; the remaining were controls. Data were obtained from medical charts, and through a standardized questionnaire about RF. Mean age of the sample (± SD was 80.6 ± 8.1 years, without statistically significant difference between cases and controls; the female:male ratio was 3:1 in both groups. Fractured women were older than men (82.5 ± 8.1 vs. 79.7 ± 7.2 years, respectively; p < 0.01. Physical activity, intake of alcohol and tobacco, and sun exposure were low in all patients. Falls among cases happened predominantly at home (p < 0.001. Among female cases, time spent in household duties was a RF (p = 0.007, which was absent in males. In multivariate analysis, the following RF were significantly more frequent: Cognitive impairment (p = 0.001, and previous falls (p < 0.0001; whereas the following protective factors were significantly different from controls: Calcium intake during youth (p < 0.0001, current calcium intake (p < 0.0001, and mechanical aid for walking (p < 0.0001. Evaluation of RF and protective factors may contribute to diminish the probability of hip

Factors associated with recurrent fifth metatarsal stress fracture.

Science.gov (United States)

Lee, Kyung-tai; Park, Young-uk; Jegal, Hyuk; Kim, Ki-chun; Young, Ki-won; Kim, Jin-su

2013-12-01

Many surgeons agree that fifth metatarsal stress fractures have a tendency toward delayed union, nonunion, and possibly refracture. Difficulty healing seems to be correlated with fracture classification. However, refracture sometimes occurs after low-grade fracture, even long after apparent resolution. The records of 168 consecutive cases of fifth metatarsal stress fracture (163 patients) treated by modified tension band wiring from March 2002 to June 2011 were evaluated retrospectively. Mean length of follow-up was 23.6 months (range, 10-112 months). Forty-nine cases classified as Torg III were bone grafted initially also. All enrolled patients were elite athletes. Eleven patients experienced nonunion and 18 refracture. The 11 nonunion cases were bone grafted. The 157 patients (excluding nonunion cases) were allocated to either a refracture group or a union group. Clinical features, such as age, weight, fracture classification, time to union, and reinjury history, were compared. Radiological parameters representing cavus deformity and fifth metatarsal head protrusion were compared to evaluate the influence of structural abnormalities. Mean group weights were significantly different (P = .041), but mean ages (P = .879), fracture grades (P = .216, P = .962), and time from surgery to rehabilitation (P = .539) were similar. No significant intergroup differences were found for talocalcaneal (TC) angle (P = .470), calcaneal pitch (CP) angle (P = .847), or talo-first metatarsal (T-MT1) angle (P = .407) on lateral radiographs; for fifth metatarsal lateral deviation (MT5-LD) angle (P = .623) on anteroposterior (AP) radiographs; or for MT5-LD angle (P = .065) on the 30-degree medial oblique radiographs. However, the mean fourth-fifth intermetatarsal (IMA4-5) angle on AP radiographs was significantly greater in the refracture group, and for Torg II cases, mean weight (P = .042), IMA4-5 angle on AP radiographs (P = .014), and MT5-LD angle (P = .043) on 30-degree medial

Effects of Material Modulus on Fracture Toughness of Human Enamel, a Natural Biocomposite

Energy Technology Data Exchange (ETDEWEB)

Mishra, Dhaneshwar; Yoo, Seung Hyun [Ajou University, Suwon (Korea, Republic of)

2011-06-15

The enamel, the upper layer of a tooth has remarkable capability of bearing severe loading on the tooth. The fracture behavior is important to understand the mechanism of load bearing and it cold be very useful for developing new materials. Non-destructive evaluation of such materials will also benefit from this knowledge. The graded microstructures of enamel were modeled by finite element analysis software and the J-integrals and the stress intensity factors were evaluated as the fracture parameters. The results show that these parameters are location dependent. Those values increase when measure in the direction of dentine enamel junction. This finding matched well with experiments and implies many useful understanding of biomaterials and applications to new materials

Stress fractures in elite cross-country athletes.

Science.gov (United States)

Laker, Scott R; Saint-Phard, Deborah; Tyburski, Mark; Van Dorsten, Brent

2007-04-01

This retrospective and comparative survey investigates an unusual number of stress fractures seen within a Division I college cross-country team. An anonymous questionnaire-designed to observe factors known to increase stress fracture incidence-was distributed to members of the current and previous seasons' teams. Running surface, sleep hours, intake of calcium, and shoe type were among the factors investigated. Eleven lower extremity stress fractures were found in nine athletes. Athletes with stress fractures reported significantly fewer workouts per week on the new track. All other study parameters had no statistically significant effect on stress fractures in these athletes.

Estimation of stress intensity factors for circumferential cracked pipes under welding residual stress filed

International Nuclear Information System (INIS)

Oh, Chang Young; Kim, Yun Jae; Oh, Young Jin; Song, Tae Kwang; Kim, Yong Beum; Oh, Young Jin; Song, Tae Kwang; Kim, Yong Beum

2012-01-01

Recently, stress corrosion cracking(SCC) have been found in dissimilar metal welds of nozzles in some pressurized water reactors and on low carbon stainless steel piping systems of boiling water reactors. The important factor of SCC is the residual stress field caused by weld. For the evaluation of crack growth analysis due to SCC, stress intensity factor under a residual stress field should be estimated. Several solutions for stress intensity factor under residual stress field were recommended in flaw assessment codes such as the American Society of Mechanical Engineers (ASME) Section XI, R6, American Petroleum Institute (API579). Some relevant works have been studied. Dong et al. evaluated stress intensity factors in welded structures. Miyazaki et al. estimated stress intensity factors of surface crack in simple stress fields. This paper presents a simple method to estimate stress intensity factors in welding residual stress field. For general application, results of structure integrity assessment codes KI solutions were compared Finite element analyses of welding simulation and cracked pipes are described. Comparison results of KI solutions and proposed simplified solution are presented in the works

Organizational Factors and Long-Term Mortality after Hip Fracture Surgery. A Cohort Study of 6143 Consecutive Patients Undergoing Hip Fracture Surgery

DEFF Research Database (Denmark)

Lund, Caterina A; Møller, Ann M; Wetterslev, Jørn

2014-01-01

OBJECTIVE: In hospital and health care organizational factors may be changed to reduce postoperative mortality. The aim of this study is to evaluate a possible association between mortality and 'length of hospital stay', 'priority of surgery', 'time of surgery', or 'surgical delay' in hip fracture...... surgery. DESIGN: Observational cohort study. SETTING: Prospectively and consecutively reported data from the Danish Anaesthesia Database were linked to The Danish National Registry of Patients and The Civil Registration System. Records on vital status, admittance, discharges, codes of diagnosis......; therefore cluster randomized clinical trials comparing different clinical set ups may be warranted evaluating health care organizational factors....

Rib stress fractures among rowers: definition, epidemiology, mechanisms, risk factors and effectiveness of injury prevention strategies.

Science.gov (United States)

McDonnell, Lisa K; Hume, Patria A; Nolte, Volker

2011-11-01

Rib stress fractures (RSFs) can have serious effects on rowing training and performance and accordingly represent an important topic for sports medicine practitioners. Therefore, the aim of this review is to outline the definition, epidemiology, mechanisms, intrinsic and extrinsic risk factors, injury management and injury prevention strategies for RSF in rowers. To this end, nine relevant books, 140 journal articles, the proceedings of five conferences and two unpublished presentations were reviewed after searches of electronic databases using the keywords 'rowing', 'rib', 'stress fracture', 'injury', 'mechanics' and 'kinetics'. The review showed that RSF is an incomplete fracture occurring from an imbalance between the rate of bone resorption and the rate of bone formation. RSF occurs in 8.1-16.4% of elite rowers, 2% of university rowers and 1% of junior elite rowers. Approximately 86% of rowing RSF cases with known locations occur in ribs four to eight, mostly along the anterolateral/lateral rib cage. Elite rowers are more likely to experience RSF than nonelite rowers. Injury occurrence is equal among sweep rowers and scullers, but the regional location of the injury differs. The mechanism of injury is multifactorial with numerous intrinsic and extrinsic risk factors contributing. Posterior-directed resultant forces arising from the forward directed force vector through the arms to the oar handle in combination with the force vector induced by the scapula retractors during mid-drive, or repetitive stress from the external obliques and rectus abdominis in the 'finish' position, may be responsible for RSF. Joint hypomobility, vertebral malalignment or low bone mineral density may be associated with RSF. Case studies have shown increased risk associated with amenorrhoea, low bone density or poor technique, in combination with increases in training volume. Training volume alone may have less effect on injury than other factors. Large differences in seat and handle

Scapular fracture: lower severity and mortality

Directory of Open Access Journals (Sweden)

Javad Salimi

Full Text Available CONTEXT AND OBJECTIVE: The presence of scapular fracture is believed to be associated with high rates of other injuries and accompanying morbidities. The aim was to study injury patterns and their overall outcomes in patients with scapula fractures. DESIGN AND SETTING: Cross-sectional study of trauma patients treated at six general hospitals in Tehran. METHODS: One-year trauma records were obtained from six general hospitals Among these, forty-one had sustained a scapular fracture and were included in this study. RESULTS: Scapular fracture occurred predominantly among 20 to 50-year-old patients (78%. Road traffic accidents (RTAs were the main cause of injury (73.2%; 30/41. Pedestrians accounted for 46.7% (14/30 of the injuries due to RTAs. Falls were the next most common cause, accounting for seven cases (17.1%. Body fractures were the most common type of scapular fractures (80%. Eighteen patients (43.9% had isolated scapular fractures. Limb fracture was the most common associated injury, detected in 18 cases (43.9%. Three patients (7.3% had severe injuries (injury severity score, ISS > 16 which resulted in one death (2.4%. The majority of the patients were treated conservatively (87.8%. CONCLUSIONS: Patients with scapula fractures have more severe underlying chest injuries and clavicle fractures. However, this did not correlate with higher rates of injury severity score, intensive care unit admission or mortality.

Postoperative mortality and morbidity in octogenarians and nonagenarians with hip fracture: an analysis of perioperative risk factors

Directory of Open Access Journals (Sweden)

MA Ren-shi

2012-02-01

Full Text Available 【Abstract】Objective: To evaluate the role of high risk factors in octogenarians and nonagenarians with hip trauma, which may lead to excessive mortality and morbi- dity postoperatively. Methods: Fifty-four octogenarians and nonagenarians patients were enrolled in the study, receiving surgical repair of hip fracture in our hospital from January 2006 to January 2010. High risk factors were recorded preoperatively in detail. Complications and survival state were followed up by telephone for 2 years postoperatively. All the data were analyzed by Chi-square test with SPSS 13.0. Results: Twenty-six males (48.1%, aged from 80 to 94 years with a mean age of 84.2 years, and twenty-eight females (51.9%, aged from 80 to 95 years with a mean age of 83.4 years, were presented in the cohort study. The hip traumas were caused by daily slight injuries (52 cases and car accidents (2 cases, respectively. Twenty-eight patients (51.9% with femoral neck fracture while 26 patients (48.1% with intertrochanteric fracture were diagnosed through an anterior-posterior pelvic radiophotograph. In this series, 39 patients (72.2% suffered from one or more comorbidities preoperatively. The morbidity was 48.1% and the major cause was urinary tract infection, while a significant difference was noted between females and males. The mortality was 20.4% with a predominant cause of acute renal failure. Conclusions: The gender should be considered as a critical high risk factor in octogenarians and nonagenarians with hip trauma postoperatively. Females are more likely to suffer complications postoperatively, which is especially obvious in senile patients over 80 years (P<0.05. Urinary tract infection is the most frequent complication after hip surgery, followed by low limb embolism and malnutrition. The mortality is dramatically greater in patients over 80 years old than those below, and major causes are acute renal failure, multiple organ dysfunction syndrome and mental

Weaning from mechanical ventilation: factors that influence intensive care nurses' decision-making.

Science.gov (United States)

Tingsvik, Catarina; Johansson, Karin; Mårtensson, Jan

2015-01-01

The aim of the study was to describe the factors that influence intensive care nurses' decision-making when weaning patients from mechanical ventilation. Patients with failing vital function may require respiratory support. Weaning from mechanical ventilation is a process in which the intensive care nurse participates in both planning and implementation. A qualitative approach was used. The data were collected by means of semi-structured interviews with 22 intensive care nurses. The interviews were transcribed and analysed using qualitative content analysis. One theme emerged: 'A complex nursing situation where the patient receives attention and which is influenced by the current care culture'. There was consensus that the overall assessment of the patient made by the intensive care nurse was the main factor that influenced the decision-making process. This assessment was a continuous process consisting of three factors: the patient's perspective as well as her/his physical and mental state. On the other hand, there was a lack of consensus about what other factors influenced the decision-making process. These factors included the care culture constituted by the characteristics of the team, the intensive care nurses' professional skills, personalities and ability to be present. The individual overall assessment of the patient enabled nursing care from a holistic perspective. Furthermore, the weaning process can be more effective and potential suffering reduced by creating awareness of the care culture's impact on the decision-making process. © 2014 British Association of Critical Care Nurses.

Irradiated dynamic fracture toughness of ASTM A533, Grade B, Class 1 steel plate and submerged arc weldment. Heavy section steel technology program technical report No. 41

International Nuclear Information System (INIS)

Davidson, J.A.; Ceschini, L.J.; Shogan, R.P.; Rao, G.V.

1976-10-01

As a result of the Heavy Section Steel Technology Program (HSST), sponsored by the Nuclear Regulatory Commission, Westinghouse Electric Corporation conducted dynamic fracture toughness tests on irradiated HSST Plate 02 and submerged arc weldment material. Testing performed at the Westinghouse Research and Development Laboratory in Pittsburgh, Pennsylvania, included 0.394T compact tension, 1.9T compact tension, and 4T compact tension specimens. This data showed that, in the transition region, dynamic test procedures resulted in lower (compared to static) fracture toughness results, and that weak direction (WR) oriented specimen data were lower than the strong direction (RW) oriented specimen results. Irradiated lower-bound fracture toughness results of the HSST Program material were well above the adjusted ASME Section III K/sub IR/ curve. An irradiated and nonirradiated 4T-CT specimen was tested during a fracture toughness test as a preliminary study to determine the effect of irradiation on the acoustic emission-stress intensity factor relation in pressure vessel grade steel. The results indicated higher levels of acoustic emission activity from the irradiated sample as compared to the unirradiated one at a given stress intensity factor (K) level

Factors in secondary prevention subsequent to distal radius fracture : Focus on physical function, co-morbidity, bone mineral density and health-related quality of life

OpenAIRE

Nordvall, Helena

2009-01-01

In Sweden approximately 25000 distal radius fractures occur annually, which is 37 % of all fractures related to osteoporosis. In this thesis, risk factors for osteoporosis, bone mineral density (BMD) and health-related quality of life (the SF-36) were compared in patients who suffered a distal radius fracture after low energy trauma with a control group matched on the basis of age, gender, and municipality of residence. The aim was also to analyse, among these patients, whether a risk factor ...

Influence of Bone Remodeling Inhibition on the Development of Experimental Stress Fractures

National Research Council Canada - National Science Library

Schaffler, Mitchell B

2005-01-01

.... Using a bisphosphonate (BIS) to suppress remodeling in the rabbit tibial stress fracture model, we found that antiresorptive therapy reduced the intensity of the stress fracture response in this model...

Predictive factors of hospital stay, mortality and functional recovery after surgery for hip fracture in elderly patients.

Science.gov (United States)

Pareja Sierra, T; Bartolomé Martín, I; Rodríguez Solís, J; Bárcena Goitiandia, L; Torralba González de Suso, M; Morales Sanz, M D; Hornillos Calvo, M

Due to its high prevalence and serious consequences it is very important to be well aware of factors that might be related to medical complications, mortality, hospital stay and functional recovery in elderly patients with hip fracture. A prospective study of a group of 130 patients aged over 75 years admitted for osteoporotic hip fracture. Their medical records, physical and cognitive status prior to the fall, fracture type and surgical treatment, medical complications and functional and social evolution after hospitalization were evaluated. Patients with greater physical disability, more severe cognitive impairment and those who lived in a nursing home before the fracture had worse functional recovery after surgery. Treatment with intravenous iron to reduce transfusions reduced hospital stay and improved walking ability. Infections and heart failure were the most frequent medical complications and were related to a longer hospital stay. The prescription of nutritional supplements for the patients with real indication improved their physical recovery after the hip fracture CONCLUSIONS: Evaluation of physical, cognitive and social status prior to hip fracture should be the basis of an individual treatment plan because of its great prognostic value. Multidisciplinary teams with continuous monitoring of medical problems should prevent and treat complications as soon as possible. Intravenous iron and specific nutritional supplements can improve functional recovery six months after hip fracture. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Acetabular Fracture

Directory of Open Access Journals (Sweden)

Chad Correa

2017-09-01

; they will show a sagittally oriented fracture line at the roof of the acetabulum on axial CT. Lastly, wall fractures should be evaluated with axial CT images. This is because wall fractures have an obliquely oriented fracture line on axial CT images at the roof of the acetabulum, as opposed to the coronal and sagittal fracture lines described with column and transverse fractures, respectively.2 Fractures are organized using the Letournel Classification based on whether the fracture site lies in the anterior or posterior walls and columns of bone. After diagnosis, early surgical intervention is critical in achieving good results.3 The majority of acetabular fractures are repaired by open reduction and internal fixation. Patients with significant osteopenia or communition benefit most from total hip arthroplasty. However, due to the complex nature of these fractures, there is potential for poor outcome regardless of the injury pattern due to contributing factors such as imperfect reduction, osteochondral defects in the acetabulum or femoral head, osteoarthritis, avascular necrosis of the femoral head, sciatic nerve injury and infection.4

Alpha radiation and in-pile annealing effects on the fracture properties of a sintered alumino borosilicate glass

International Nuclear Information System (INIS)

Bevilacqua, Arturo M.; Prado, Miguel O.; Messi de Bernasconi, Norma B.; Heredia, Arturo D.; Sanfilippo, Miguel

1999-01-01

The alpha radiation and the in-pile during irradiation effects on the hardness, the crack nucleation and the fracture toughness of the German alumino borosilicate glass SG7 were investigated by using the Vickers indentation. Cold pressed and sintered samples were irradiated with thermal neutrons, in the Argentine nuclear reactors RA-3 and RA-6, to produce alpha particles in the whole volume of the glass by means of the (n, alpha)-reaction with B-10. The Vickers hardness, the crack nucleation, as 50 percent fracture probability load, plotted as the Weibull's fracture probability distribution function and the fracture toughness, as critical stress intensity factor K Ic , were correlated to the four cumulative disintegration values. It was ascertained that: a) the Vickers hardness decreases from 5.6 GPa for the non-irradiated sample up to 4.7 GPa for the sample irradiated 70 h at the lower neutron flux (4.0 x 10 - sup 18 - alpha disintegration per cm - sup 3 -), b) the 50 % fracture probability load increases from 1.4 N for the non-irradiated sample up to 4.7 g for the sample irradiated 22 h at the higher flux (6.8 x 10 - sup 18 - alpha disintegration per cm - sup 3 -), and c) the stress intensity factor increases from 0.80 MPa.m - sup 1/2 - for the non irradiated sample up to 0.86 MPa.m - sup 1/2 - for the sample mentioned in b). The in-pile annealing was analyzed by comparing the crack nucleation after irradiation with data obtained by heavy ion irradiation followed by thermal annealing. Results for the SG7 glass were compared to those for soda-lime and borosilicate glasses. (author)

Application of artificial intelligence to characterize naturally fractured zones in Hassi Messaoud Oil Field, Algeria

Energy Technology Data Exchange (ETDEWEB)

El Ouahed, Abdelkader Kouider; Mazouzi, Amine [Sonatrach, Rue Djenane Malik, Hydra, Algiers (Algeria); Tiab, Djebbar [Mewbourne School of Petroleum and Geological Engineering, The University of Oklahoma, 100 East Boyd Street, SEC T310, Norman, OK, 73019 (United States)

2005-12-15

In highly heterogeneous reservoirs classical characterization methods often fail to detect the location and orientation of the fractures. Recent applications of Artificial Intelligence to the area of reservoir characterization have made this challenge a possible practice. Such a practice consists of seeking the complex relationship between the fracture index and some geological and geomechanical drivers (facies, porosity, permeability, bed thickness, proximity to faults, slopes and curvatures of the structure) in order to obtain a fracture intensity map using Fuzzy Logic and Neural Network. This paper shows the successful application of Artificial Intelligence tools such as Artificial Neural Network and Fuzzy Logic to characterize naturally fractured reservoirs. A 2D fracture intensity map and fracture network map in a large block of Hassi Messaoud field have been developed using Artificial Neural Network and Fuzzy Logic. This was achieved by first building the geological model of the permeability, porosity and shale volume using stochastic conditional simulation. Then by applying some geomechanical concepts first and second structure directional derivatives, distance to the nearest fault, and bed thickness were calculated throughout the entire area of interest. Two methods were then used to select the appropriate fracture intensity index. In the first method well performance was used as a fracture index. In the second method a Fuzzy Inference System (FIS) was built. Using this FIS, static and dynamic data were coupled to reduce the uncertainty, which resulted in a more reliable Fracture Index. The different geological and geomechanical drivers were ranked with the corresponding fracture index for both methods using a Fuzzy Ranking algorithm. Only important and measurable data were selected to be mapped with the appropriate fracture index using a feed forward Back Propagation Neural Network (BPNN). The neural network was then used to obtain a fracture intensity

Fracture healing: Quantitative three-phase bone scintigraphy as a prognostic factor

International Nuclear Information System (INIS)

Dodig, D.; Kasal, B.; Kragic-Pranic, A.; Predic, P.

2002-01-01

Aim: Careful clinical examination and conventional radiography, together with other standard methods for evaluation of bone fracture healing, are frequently inconclusive. Furthermore, it is difficult to predict the complications of healing on the basis of clinical and radiographic findings only. Bone scintigraphy plays an important role in detecting bone fractures. This method is very sensitive, but not enough specific. The aim of this work was to evaluate the role of three-phase bone scintigraphy in the healing prognosis of long bone fractures. Material and Methods: We evaluated the three elements (perfusion, blood pool and static image) of three-phase bone scintigraphy in early prognosis of the course of fracture healing in patients with fractures of femur or tibia. Three-phase bone scintigraphy was performed in 73 patients. The patients were divided into 4 groups according to X-ray and clinical examination: 1) Non operated patients with stable fracture, 2) Operated patients with unstable fracture (infection), 3) Fractures with delayed union, 4) Patients with pseudoarthrosis. Using region of interest (ROI) method we compared the activity on the site of fracture with the activity on the symmetrical place in the healthy bone. The relative indices for each group of patients and for each element of three-bone scintigraphy were calculated in order to make possible the follow up of the fracture healing and to obtain data for prognosis and evaluation of possible complications. Results: The most valuable results were obtained by quantitative analysis of perfusion data immediately after trauma and 2-3 weeks later. Our results show a high diagnostic accuracy in identifying infection by perfusion scintigrams immediately after trauma. The perfusion indices obtained immediately and after 2-3 weeks could predict delayed union after the trauma. Quantitative analysis of blood pool phase gave no data of clinical significance in distinguishing various pathologies. Conclusion: Our

Prior nonhip limb fracture predicts subsequent hip fracture in institutionalized elderly people.

Science.gov (United States)

Nakamura, K; Takahashi, S; Oyama, M; Oshiki, R; Kobayashi, R; Saito, T; Yoshizawa, Y; Tsuchiya, Y

2010-08-01

This 1-year cohort study of nursing home residents revealed that historical fractures of upper limbs or nonhip lower limbs were associated with hip fracture (hazard ratio = 2.14), independent of activities of daily living (ADL), mobility, dementia, weight, and type of nursing home. Prior nonhip fractures are useful for predicting of hip fracture in institutional settings. The aim of this study was to evaluate the utility of fracture history for the prediction of hip fracture in nursing home residents. This was a cohort study with a 1-year follow-up. Subjects were 8,905 residents of nursing homes in Niigata, Japan (mean age, 84.3 years). Fracture histories were obtained from nursing home medical records. ADL levels were assessed by caregivers. Hip fracture diagnosis was based on hospital medical records. Subjects had fracture histories of upper limbs (5.0%), hip (14.0%), and nonhip lower limbs (4.6%). Among historical single fractures, only prior nonhip lower limbs significantly predicted subsequent fracture (adjusted hazard ratio, 2.43; 95% confidence interval (CI), 1.30-4.57). The stepwise method selected the best model, in which a combined historical fracture at upper limbs or nonhip lower limbs (adjusted hazard ratio, 2.14; 95% CI, 1.30-3.52), dependence, ADL levels, mobility, dementia, weight, and type of nursing home independently predicted subsequent hip fracture. A fracture history at upper or nonhip lower limbs, in combination with other known risk factors, is useful for the prediction of future hip fracture in institutional settings.

What accounts for rib fractures in older adults?

Science.gov (United States)

Wuermser, Lisa-Ann; Achenbach, Sara J; Amin, Shreyasee; Khosla, Sundeep; Melton, L Joseph

2011-01-01

To address the epidemiology of rib fractures, an age- and sex-stratified random sample of 699 Rochester, Minnesota, adults age 21-93 years was followed in a long-term prospective study. Bone mineral density (BMD) was assessed at baseline, and fractures were ascertained by periodic interview and medical record review. During 8560 person-years of followup (median, 13.9 years), 56 subjects experienced 67 rib fracture episodes. Risk factors for falling predicted rib fractures as well as BMD, but both were strongly age-related. After age-adjustment, BMD was associated with rib fractures in women but not men. Importantly, rib fractures attributed to severe trauma were associated with BMD in older individuals of both sexes. Self-reported heavy alcohol use doubled fracture risk but did not achieve significance due to limited statistical power. Bone density, along with heavy alcohol use and other risk factors for falling, contributes to the risk of rib fractures, but no one factor predominates. Older women with rib fractures, regardless of cause, should be considered for an osteoporosis evaluation, and strategies to prevent falling should be considered in both sexes.

What Accounts for Rib Fractures in Older Adults?

Directory of Open Access Journals (Sweden)

Lisa-Ann Wuermser

2011-01-01

Full Text Available To address the epidemiology of rib fractures, an age- and sex-stratified random sample of 699 Rochester, Minnesota, adults age 21–93 years was followed in a long-term prospective study. Bone mineral density (BMD was assessed at baseline, and fractures were ascertained by periodic interview and medical record review. During 8560 person-years of followup (median, 13.9 years, 56 subjects experienced 67 rib fracture episodes. Risk factors for falling predicted rib fractures as well as BMD, but both were strongly age-related. After age-adjustment, BMD was associated with rib fractures in women but not men. Importantly, rib fractures attributed to severe trauma were associated with BMD in older individuals of both sexes. Self-reported heavy alcohol use doubled fracture risk but did not achieve significance due to limited statistical power. Bone density, along with heavy alcohol use and other risk factors for falling, contributes to the risk of rib fractures, but no one factor predominates. Older women with rib fractures, regardless of cause, should be considered for an osteoporosis evaluation, and strategies to prevent falling should be considered in both sexes.

What Accounts for Rib Fractures in Older Adults?

Science.gov (United States)

Wuermser, Lisa-Ann; Achenbach, Sara J.; Amin, Shreyasee; Khosla, Sundeep; Melton, L. Joseph

2011-01-01

To address the epidemiology of rib fractures, an age- and sex-stratified random sample of 699 Rochester, Minnesota, adults age 21–93 years was followed in a long-term prospective study. Bone mineral density (BMD) was assessed at baseline, and fractures were ascertained by periodic interview and medical record review. During 8560 person-years of followup (median, 13.9 years), 56 subjects experienced 67 rib fracture episodes. Risk factors for falling predicted rib fractures as well as BMD, but both were strongly age-related. After age-adjustment, BMD was associated with rib fractures in women but not men. Importantly, rib fractures attributed to severe trauma were associated with BMD in older individuals of both sexes. Self-reported heavy alcohol use doubled fracture risk but did not achieve significance due to limited statistical power. Bone density, along with heavy alcohol use and other risk factors for falling, contributes to the risk of rib fractures, but no one factor predominates. Older women with rib fractures, regardless of cause, should be considered for an osteoporosis evaluation, and strategies to prevent falling should be considered in both sexes. PMID:22028986

Geological discrete fracture network model for the Olkiluoto site, Eurajoki, Finland. Version 2.0

International Nuclear Information System (INIS)

Fox, A.; Forchhammer, K.; Pettersson, A.; La Pointe, P.; Lim, D-H.

2012-06-01

This report describes the methods, analyses, and conclusions of the modeling team in the production of the 2010 revision to the geological discrete fracture network (DFN) model for the Olkiluoto Site in Finland. The geological DFN is a statistical model for stochastically simulating rock fractures and minor faults at a scale ranging from approximately 0.05 m to approximately 565m; deformation zones are expressly excluded from the DFN model. The DFN model is presented as a series of tables summarizing probability distributions for several parameters necessary for fracture modeling: fracture orientation, fracture size, fracture intensity, and associated spatial constraints. The geological DFN is built from data collected during site characterization (SC) activities at Olkiluoto, which is selected to function as a final deep geological repository for spent fuel and nuclear waste from the Finnish nuclear power program. Data used in the DFN analyses include fracture maps from surface outcrops and trenches, geological and structural data from cored drillholes, and fracture information collected during the construction of the main tunnels and shafts at the ONKALO laboratory. Unlike the initial geological DFN, which was focused on the vicinity of the ONKALO tunnel, the 2010 revisions present a model parameterization for the entire island. Fracture domains are based on the tectonic subdivisions at the site (northern, central, and southern tectonic units) presented in the Geological Site Model (GSM), and are further subdivided along the intersection of major brittle-ductile zones. The rock volume at Olkiluoto is dominated by three distinct fracture sets: subhorizontally-dipping fractures striking north-northeast and dipping to the east that is subparallel to the mean bedrock foliation direction, a subvertically-dipping fracture set striking roughly north-south, and a subvertically-dipping fracture set striking approximately east-west. The subhorizontally-dipping fractures

Geological discrete fracture network model for the Olkiluoto site, Eurajoki, Finland. Version 2.0

Energy Technology Data Exchange (ETDEWEB)

Fox, A.; Forchhammer, K.; Pettersson, A. [Golder Associates AB, Stockholm (Sweden); La Pointe, P.; Lim, D-H. [Golder Associates Inc. (Finland)

2012-06-15

This report describes the methods, analyses, and conclusions of the modeling team in the production of the 2010 revision to the geological discrete fracture network (DFN) model for the Olkiluoto Site in Finland. The geological DFN is a statistical model for stochastically simulating rock fractures and minor faults at a scale ranging from approximately 0.05 m to approximately 565m; deformation zones are expressly excluded from the DFN model. The DFN model is presented as a series of tables summarizing probability distributions for several parameters necessary for fracture modeling: fracture orientation, fracture size, fracture intensity, and associated spatial constraints. The geological DFN is built from data collected during site characterization (SC) activities at Olkiluoto, which is selected to function as a final deep geological repository for spent fuel and nuclear waste from the Finnish nuclear power program. Data used in the DFN analyses include fracture maps from surface outcrops and trenches, geological and structural data from cored drillholes, and fracture information collected during the construction of the main tunnels and shafts at the ONKALO laboratory. Unlike the initial geological DFN, which was focused on the vicinity of the ONKALO tunnel, the 2010 revisions present a model parameterization for the entire island. Fracture domains are based on the tectonic subdivisions at the site (northern, central, and southern tectonic units) presented in the Geological Site Model (GSM), and are further subdivided along the intersection of major brittle-ductile zones. The rock volume at Olkiluoto is dominated by three distinct fracture sets: subhorizontally-dipping fractures striking north-northeast and dipping to the east that is subparallel to the mean bedrock foliation direction, a subvertically-dipping fracture set striking roughly north-south, and a subvertically-dipping fracture set striking approximately east-west. The subhorizontally-dipping fractures

Naturally fractured reservoirs-yet an unsolved mystery

International Nuclear Information System (INIS)

Zahoor, M.K.

2013-01-01

Some of the world's most profitable reservoirs are assumed to be naturally fractured reservoirs (NFR). Effective evaluation, prediction and planning of these reservoirs require an early recognition of the role of natural fractures and then a comprehensive study of factors which affect the flowing performance through these fractures is necessary. As NFRs are the combination of matrix and fractures mediums so their analysis varies from non-fractured reservoirs. Matrix acts as a storage medium while mostly fluid flow takes place from fracture network. Many authors adopted different approaches to understand the flow behavior in such reservoirs. In this paper a broad review about the previous work done in naturally fractured reservoirs area is outlined and a different idea is initiated for the NFR simulation studies. The role of capillary pressure in natural fractures is always been a key factor for accurate recovery estimations. Also recovery through these reservoirs is dependent upon grid block shape while doing NFR simulation. Some authors studied above mentioned factors in combination with other rock properties to understand the flow behavior in such reservoirs but less emphasis was given for checking the effects on recovery estimations by the variations of only fracture capillary pressures and grid block shapes. So there is need to analyze the behavior of NFR for the mentioned conditions. (author)

Fracture patterns and the energy release rate of phosphorene.

Science.gov (United States)

Liu, Ning; Hong, Jiawang; Pidaparti, Ramana; Wang, Xianqiao

2016-03-14

Phosphorene, also known as monolayer black phosphorus, has been enjoying popularity in electronic devices due to its superior electrical properties. However, it's relatively low Young's modulus, low fracture strength and susceptibility to structural failure have limited its application in mechanical devices. Therefore, in order to design more mechanically reliable devices that utilize phosphorene, it is necessary to explore the fracture patterns and energy release rate of phosphorene. In this study, molecular dynamics simulations are performed to investigate phosphorene's fracture mechanism. The results indicate that fracture under uniaxial tension along the armchair direction is attributed to a break in the interlayer bond angles, while failure in the zigzag direction is triggered by the break in both intra-layer angles and bonds. Furthermore, we developed a modified Griffith criterion to analyze the energy release rate of phosphorene and its dependence on the strain rates and orientations of cracks. Simulation results indicate that phosphorene's energy release rate remains almost unchanged in the armchair direction while it fluctuates intensively in the zigzag direction. Additionally, the strain rate was found to play a negligible role in the energy release rate. The geometrical factor α in the Griffith's criterion is almost constant when the crack orientation is smaller than 45 degree, regardless of the crack orientation and loading direction. Overall, these findings provide helpful insights into the mechanical properties and failure behavior of phosphorene.

Structural-Diagenetic Controls on Fracture Opening in Tight Gas Sandstone Reservoirs, Alberta Foothills

Science.gov (United States)

Ukar, Estibalitz; Eichhubl, Peter; Fall, Andras; Hooker, John

2013-04-01

In tight gas reservoirs, understanding the characteristics, orientation and distribution of natural open fractures, and how these relate to the structural and stratigraphic setting are important for exploration and production. Outcrops provide the opportunity to sample fracture characteristics that would otherwise be unknown due to the limitations of sampling by cores and well logs. However, fractures in exhumed outcrops may not be representative of fractures in the reservoir because of differences in burial and exhumation history. Appropriate outcrop analogs of producing reservoirs with comparable geologic history, structural setting, fracture networks, and diagenetic attributes are desirable but rare. The Jurassic to Lower Cretaceous Nikanassin Formation from the Alberta Foothills produces gas at commercial rates where it contains a network of open fractures. Fractures from outcrops have the same diagenetic attributes as those observed in cores fractures relative to fold cores, hinges and limbs, 2) compare the distribution and attributes of fractures in outcrop vs. core samples, 3) estimate the timing of fracture formation relative to the evolution of the fold-and-thrust belt, and 4) estimate the degradation of fracture porosity due to postkinematic cementation. Cathodoluminescence images of cemented fractures in both outcrop and core samples reveal several generations of quartz and ankerite cement that is synkinematic and postkinematic relative to fracture opening. Crack-seal textures in synkinematic quartz are ubiquitous, and well-developed cement bridges abundant. Fracture porosity may be preserved in fractures wider than ~100 microns. 1-D scanlines in outcrop and core samples indicate fractures are most abundant within small parasitic folds within larger, tight, mesoscopic folds. Fracture intensity is lower away from parasitic folds; intensity progressively decreases from the faulted cores of mesoscopic folds to their forelimbs, with lowest intensities within

Pathogenesis of osteoporotic hip fractures.

Science.gov (United States)

McClung, Michael R

2003-01-01

Osteoporosis is characterized late in the course of the disease by an increased risk of fracture, particularly in the elderly. It occurs in both sexes, affecting approximately 8 million women and 2 million men aged > or = 50 years (1). While low bone density is a predictor of fractures, it is not the only determinant of fracture risk. Other factors include advanced age, altered bone quality, a personal or family history of falls, frailty, poor eyesight, debilitating diseases, and high bone turnover. A diet with sufficient calcium and vitamin D is important to minimize bone loss and, along with regular exercise, to maintain muscle strength. Bisphosphonates have been shown to reduce the risk of hip fracture. For elderly patients, the use of hip protectors may be used as a treatment of last resort. Regardless of the age of the patient, individual patient risk factors must be considered to target appropriate treatment and prevent fracture.

On the nature of groundwater flow paths: Observations at fractures and fracture coating at road-cuts

International Nuclear Information System (INIS)

Lindberg, A.; Hellmuth, K.-H.

2001-01-01

Preliminary investigations were conducted at fractures and their surface coatings exposed along recently quarried road-cuts to the north and east of Helsinki. While (sub)horizontal fractures were usually rare at depths more than a few meters, (sub)vertical fractures were dominating. Fracture fillings/coatings were mostly absent in the formers and generally thin in the latters. Often these fillings/coatings were representative for processes which occurred in the far past at conditions others than present ambient ones. But, on the other hand only a few cases of more intense rock matrix alteration in connection with these processes were observed. Post-glacial weathering has caused at many of the investigated sites surficial oxidation of Fe(II)-rich minerals which has led to mostly thin coatings of fracture surfaces by soft amorphous Fe(III)-oxyhydroxides. Surface coatings were generally homogeneous with fairly even surface structures. It was found that at road-cuts huge areas of undamaged fracture surfaces were accessable to investigations. These can serve for demonstration purposes for the nature of contact surface between groundwater and rock. Despite some oxidation, these exposures give a fairly representative impression of the situation at greater depth where similar fracture types were reported in repository site investigations. (orig.)

Assessment of Outcomes of Treatment of Fractures of Distal Femur with a Locking Plate Taking into Account Factors Influencing the Result.

Science.gov (United States)

Pakuła, Grzegorz; Kwiatkowski, Krzysztof; Kuczmera, Piotr; Fudalej, Piotr

2015-10-01

The aim of this paper is to evaluate the results of treatment of distal femoral fractures (DFF) fixed with locking plates and analysis of factors that influence the final outcome. The patients were treated at the Department of Traumatology and Orthopedics, Military Medical Institute in Warsaw, and the Department of Orthopedics and Traumatology, 4th Military Research Hospital in Wroclaw. We analysed 39 patients with 42 fractures of the distal femur. Treatment results were analysed using the KOOS and KSS scales. Factors influencing the outcome were also investigated. Statistical analysis was performed using STATISTICA v. 10. Mean KOOS scores indicate a predominance of poor outcomes, while mean KSS scores indicate good outcomes. Treatment outcomes were significantly influenced by pain and limited mobility. 1. Subjective evaluation of treatment of fractures of the distal femur using the KOOS scale per form edworse than a clinical evaluation using the KSS. 2. Post-operative management should emphasise pain relief and restoration of the performance of the treated lower limb to ensure good mobility without crutches. 3. Despite the use of modern operational methods of fracture fixation, treatment of distal femur fractures is still a challenge.

Incidence of and Risk Factors for Knee Collateral Ligament Injuries With Proximal Tibia Fractures: A Study of 32,441 Patients.

Science.gov (United States)

Samuel, Andre M; Diaz-Collado, Pablo J; Szolomayer, Lauren K; Wiznia, Daniel H; Chan, Wayne W; Lukasiewicz, Adam M; Basques, Bryce A; Bohl, Daniel D; Grauer, Jonathan N

2018-03-01

Proximal tibia fractures are associated with concurrent collateral ligament injuries. Failure to recognize these injuries may lead to chronic knee instability. The purpose of this study was to identify risk factors for concurrent collateral ligament injuries with proximal tibia fractures and their association with inpatient outcomes. A total of 32,441 patients with proximal tibia fractures were identified in the 2011-2012 National Trauma Data Bank. A total of 1445 (4.5%) had collateral ligament injuries, 794 (2.4%) had injuries to both collateral ligaments, 456 (1.4%) had a medial collateral ligament injury only, and 195 (0.6%) had a lateral collateral ligament injury only. On multivariate analysis, risk factors found to be associated with collateral ligament injuries included distal femur fracture (odds ratio, 2.1), pedestrian struck by motor vehicle (odds ratio, 2.0), obesity (odds ratio, 1.6), young age (odds ratio, 1.9 for 18 to 29 years vs 40 to 49 years), motorcycle accident (odds ratio, 1.5), and Injury Severity Score of 20 or higher (odds ratio, 1.4). In addition, patients with simultaneous injuries to both collateral ligaments had higher odds of inpatient adverse events (odds ratio, 1.51) and longer hospital stay (mean, 2.27 days longer). The risk factors reported by this study can be used to identify patients with proximal tibia fractures who may warrant more careful and thorough evaluation and imaging of their knee collateral ligaments. [Orthopedics. 2018; 41(2):e268-e276.]. Copyright 2018, SLACK Incorporated.

Femoral neck fractures after removal of hardware in healed trochanteric fractures.

Science.gov (United States)

Barquet, Antonio; Giannoudis, Peter V; Gelink, Andrés

2017-12-01

Hardware removal in healed trochanteric fractures (TF) in the absence of infection or significant mechanical complications is rarely indicated. However, in patients with persistent pain, prominent material and discomfort in the activities of daily living, the implant is eventually removed. Publications of ipsilateral femoral neck fracture after removal of implants from healed trochanteric fractures (FNFARIHTF) just because of pain or discomfort are rare. The purpose of this systematic review of the literature is to report on the eventual risk factors, the mechanisms, the clinical presentation, and frequency, and to pay special emphasis in their prevention. A comprehensive review of the literature was undertaken using the PRISMA guidelines with no language restriction. Case reports of FNFARIHTF and series of TF with cases of FNFARIHTF due to pain or discomfort published between inception of journals to December 2016 were eligible for inclusion. Relevant information was divided in two parts. Part I included the analysis of cases of FNFARIHTF, with the objective of establishing the eventual risk factors, mechanisms and pathoanatomy, clinical presentation and diagnosis, treatment and prevention. Part II analyzed series of TF which included cases of FNFARIHTF for assessing the incidence of femoral neck fractures in this condition. Overall 24 publications with 45 cases of FNFARIHTF met the inclusion criteria. We found that the only prevalent factors for FNFARIHTF were: 1) preexisisting systemic osteoporosis, as most patients were older and elder females, with lower bone mineral density and bone mass; 2) local osteoporosis as a result of preloading by the fixation device in the femoral neck, leading to stress protection, reducing the strain at the neck, and increasing bone loss and weakness; and 3) the removal of hardware from the femoral neck, with reduction of the failure strength of the neck. The femoral neck fractures were spontaneous, i.e. not related to trauma or

Percutaneous Vertebroplasty for Osteoporotic Compression Fracture: Multivariate Study of Predictors of New Vertebral Body Fracture

International Nuclear Information System (INIS)

Komemushi, Atsushi; Tanigawa, Noboru; Kariya, Shuji; Kojima, Hiroyuki; Shomura, Yuzo; Komemushi, Sadao; Sawada, Satoshi

2006-01-01

Purpose. To investigate the risk factors and relative risk of new compression fractures following vertebroplasty. Methods. Initially, we enrolled 104 consecutive patients with vertebral compression fractures caused by osteoporosis. A total of 83 of the 104 patients visited our hospital for follow-up examinations for more than 4 weeks after vertebroplasty. Logistic regression analysis of the data obtained from these 83 patients was used to determine relative risks of recurrent compression fractures, using 13 different factors. Results. We identified 59 new fractures in 30 of the 83 patients: 41 new fractures in vertebrae adjacent to treated vertebrae; and 18 new fractures in vertebrae not adjacent to treated vertebrae. New fractures occurred in vertebrae adjacent to treated vertebrae significantly more frequently than in vertebrae not adjacent to treated vertebrae. Only cement leakage into the disk was a significant predictor of new vertebral body fracture after vertebroplasty (odds ratio = 4.633). None of the following covariates were associated with increased risk of new fracture: age, gender, bone mineral density, the number of vertebroplasty procedures, the number of vertebrae treated per procedure, the cumulative number of vertebrae treated, the presence of a single untreated vertebra between treated vertebrae, the presence of multiple untreated vertebrae between treated vertebrae, the amount of bone cement injected per procedure, the cumulative amount of bone cement injected, cement leakage into the soft tissue around the vertebra, and cement leakage into the vein

Effects of "vitex agnus castus" extract and magnesium supplementation, alone and in combination, on osteogenic and angiogenic factors and fracture healing in women with long bone fracture.

Science.gov (United States)

Eftekhari, Mohammad Hassan; Rostami, Zahra Hassanzadeh; Emami, Mohammad Jafar; Tabatabaee, Hamid Reza

2014-01-01

The purpose of this study was to investigate the effects of the combination of vitex agnus castus extract, as a source of phytoestrogens, plus magnesium supplementation on osteogenic and angiogenic factors and callus formation in women with long bone fracture. In a double-blind randomized placebo controlled trial, 64 women with long bone fracture, 20-45 years old, were randomly allocated to receive 1) one Agnugol tablet (4 mg dried fruit extract of vitex agnus castus) plus 250 mg magnesium oxide (VAC + Mg group (n = 10)), 2) one Agnugol tablet plus placebo (VAC group (n = 15)), 3) placebo plus 250 mg magnesium oxide (Mg group (n = 12)), or 4) placebo plus placebo (placebo group (n = 14)) per day for 8 weeks. At baseline and endpoint of the trial, serum alkaline phosphatase, osteocalcin, and vascular endothelial growth factor (VEGF) were measured together with radiological bone assessment. There were no significant differences in the characteristic aspects of concern between the four groups at baseline. Despite the increased level of alkaline phosphatase in the VAC group (188.33 ± 16.27 to 240.40 ± 21.49, P = 0.05), administration of VAC + Mg could not increase alkaline phosphatase activity. However, treatment with VAC + Mg significantly enhanced the osteocalcin level. The serum concentration of VEGF was increased in the VAC group (269.04 ± 116.63 to 640.03 ± 240.16, P vitex agnus castus plus magnesium may promote fracture healing. However, more studies need to further explore the roles of vitex agnus castus in fracture repair processes.

Fracture propagation in gas pipelines - relevance to submarine lines

Energy Technology Data Exchange (ETDEWEB)

Fearnehough, G D [British Gas Corp., Newcastle upon Tyne. Engineering Research Station

1976-09-01

This paper reviews the factors which control fracture propagation in pipes and suggests how they are influenced by submarine environments. If fracture arrest capability is required then these factors should be considered in terms of the design philosophy and the maximum tolerable length of fracture which can be repaired. The paper shows that brittle fracture characteristics of submarine pipelines are probably similar to land based lines and fracture arrest can only be guaranteed by appropriate material toughness specification. Resistance to ductile fracture propagation in submarine lines is enhanced by lower design stresses, thicker pipe, concrete coating and the effect of hydrostatic head on gas dynamics. However, additional factors due to submarine design can be deleterious viz: uncertainty about backfill integrity and a tendency of thicker steels to low fracture resistance arising from 'separation' formation. Attention is drawn to problems which may arise with transportation of gases rich in hydrocarbons and the use of mechanical methods of fracture arrest.

Comparison of tibial shaft ski fractures in children and adults.

Science.gov (United States)

Hamada, Tomo; Matsumoto, Kazu; Ishimaru, Daichi; Sumi, Hiroshi; Shimizu, Katsuji

2014-09-01

To examine whether child and adult skiers have different risk factors or mechanisms of injury for tibial shaft fractures. Descriptive epidemiological study. Prospectively analyzed the epidemiologic factors, injury types, and injury mechanisms at Sumi Memorial Hospital. This study analyzed information obtained from 276 patients with tibial fractures sustained during skiing between 2004 and 2012. We focused on 174 ski-related tibial shaft fractures with respect to the following factors: age, gender, laterality of fracture, skill level, mechanism of fracture (fall vs collision), scene of injury (steepness of slope), snow condition, and weather. Fracture pattern was graded according to Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification and mechanical direction [external (ER) or internal rotation (IR)]. Tibial shaft fractures were the most common in both children (89.3%) and adults (47.4%). There were no significant differences in gender, side of fracture, mechanism of fracture, snow condition, or weather between children and adults. Skill levels were significantly lower in children than in adults (P differences in some of these parameters, suggesting that child and adult skiers have different risk factors or mechanisms of injury for tibial shaft fractures.

Dependence of the specific essential work of fracture in mode I in commercially pure copper with thickener

International Nuclear Information System (INIS)

Ochoa M, Herman; Monsalve G, Alberto

2004-01-01

Due to the great ductility of DHP copper, the classic characterization of the fracture's lineal mechanics with the critical intensity factor of K 10 tensions fails because of the increased amount of plastic deformation that the material displays before fracturing. For this reason other parameters such as the integral J are also not able to characterize the fracture phenomenon. Therefore there is a need to define a more appropriate parameter, that is able to describe the breakage phenomenon in this type of material: the specific essential work of fracture that includes the large amount of plastic deformation that can absorb materials with definite ductile behavior. Tests with DENT (Double Edge Notched Tension) pieces were carried out for the calculation of the specific essential fracture work, according to the pre-standard ESIS 1995. These tests have been carried out with pieces of different ligament lengths, so that the specific fracture energy (W sf ) correlates with the ligament length, allowing the value of the specific essential fracture work (W sf ) to be calculated. Tests have been made using pieces of different thicknesses to establish the relationship between specific essential fracture work and the thickness of the material, finding that the value of W sf increases with the increased thickness of the material (CW)

Epidemiology of open tibia fractures in a population-based database: update on current risk factors and clinical implications.

Science.gov (United States)

Weber, Christian David; Hildebrand, Frank; Kobbe, Philipp; Lefering, Rolf; Sellei, Richard M; Pape, Hans-Christoph

2018-02-02

Open tibia fractures usually occur in high-energy mechanisms and are commonly associated with multiple traumas. The purposes of this study were to define the epidemiology of open tibia fractures in severely injured patients and to evaluate risk factors for major complications. A cohort from a nationwide population-based prospective database was analyzed (TraumaRegister DGU ® ). Inclusion criteria were: (1) open or closed tibia fracture, (2) Injury Severity Score (ISS) ≥ 16 points, (3) age ≥ 16 years, and (4) survival until primary admission. According to the soft tissue status, patients were divided either in the closed (CTF) or into the open fracture (OTF) group. The OTF group was subdivided according to the Gustilo/Anderson classification. Demographic data, injury mechanisms, injury severity, surgical fracture management, hospital and ICU length of stay and systemic complications (e.g., multiple organ failure (MOF), sepsis, mortality) were collected and analyzed by SPSS (Version 23, IBM Inc., NY, USA). Out of 148.498 registered patients between 1/2002 and 12/2013; a total of 4.940 met the inclusion criteria (mean age 46.2 ± 19.4 years, ISS 30.4 ± 12.6 points). The CTF group included 2000 patients (40.5%), whereas 2940 patients (59.5%) sustained open tibia fractures (I°: 49.3%, II°: 27.5%, III°: 23.2%). High-energy trauma was the leading mechanism in case of open fractures. Despite comparable ISS and NISS values in patients with closed and open tibia fractures, open fractures were significantly associated with higher volume resuscitation (p Open tibia fractures are common in multiple trauma patients and are therefore associated with increased resuscitation requirements, more surgical procedures and increased in-hospital length of stay. However, increased systemic complications are not observed if a soft tissue adapted surgical protocol is applied.

Prospective study of ankle and foot fractures in elderly women

Directory of Open Access Journals (Sweden)

Yadagiri Surender Rao

2015-01-01

Full Text Available The epidemiology of ankle fractures in old people is changing as time passes on. The incidence of ankle fractures increases with advancing age. The study conducted was among a rural popula-tion which comprised of 68 women (32 women with ankle fractures & 36 women with foot fractures. Patients studied were in the age group more than 50 years. The study highlights the etiological & risk factors for fractures of ankle & foot. The commonest ankle fracture was the lateral malleolar fracture & the commonest foot fracture was the 5th Metatarsal fracture. Diabetes is a risk factor which increases the occurrence of ankle and foot injuries.

Traumatic Vertebral Fractures and Concomitant Fractures of the Rib in Southwest China, 2001 to 2010

Science.gov (United States)

Wang, Hongwei; Zhou, Yue; Ou, Lan; Li, Changqing; Liu, Jun; Xiang, Liangbi

2015-01-01

Abstract To our knowledge, the clinical characteristics of traumatic vertebral fractures and concomitant fractures of the rib (TVF-RF) have not been described in previous studies. To investigate the clinical characteristics of patients managed for TVF-RF. A retrospective study of 3142 patients who presented with traumatic vertebral fractures was performed. Two hundred twenty-six patients (7.2%) suffered from TVF-RF. Incidence rate ratios were then calculated with respect to the level of injury to the spine, the ASIA classification of neurological deficits and age. There were 171 male (75.7%) and 55 female (24.3%) patients with a mean age of 43.8 years. The most common mechanisms were falls from high heights in 81 cases and road traffic crashes in 67 cases. Right-sided rib injury occurred in 106 cases, left-sided injury occurred in 76 cases, and bilateral injury occurred in 44 cases. The most frequent location of the rib fractures was from the fourth rib to the ninth rib (70.3%, 510/725). Initial pulmonary complications (IPC) after trauma occurred in 116 cases (51.3%). The mortality rate for the entire group was 1.3% (3/226). The patients with thoracic vertebral fractures and neurological deficits had a higher frequency of multiple rib fractures and IPC than the other patients (P rib fractures, the frequency of IPC and mean intensive care unit (ICU) length of stay also increased. The rates of complications for patients with rib fractures were significantly different from those without rib fractures. We should pay much attention to the patients who presented with thoracic vertebral fractures and neurological deficits for minimizing further complications and mortality in such patients who had a higher frequency of multiple rib fractures and IPC than the other patients. PMID:26554809

Inaccuracy in self-report of fractures may underestimate association with health outcomes when compared with medical record based fracture registry

International Nuclear Information System (INIS)

Siggeirsdottir, Kristin; Aspelund, Thor; Sigurdsson, Gunnar; Mogensen, Brynjolfur; Chang, Milan; Jonsdottir, Birna; Eiriksdottir, Gudny; Launer, Lenore J.; Harris, Tamara B.; Jonsson, Brynjolfur Y.; Gudnason, Vilmundur

2007-01-01

Introduction and objective Misreporting fractures in questionnaires is known. However, the effect of misreporting on the association of fractures with subsequent health outcomes has not been examined. Methods Data from a fracture registry (FR) developed from an extensive review of radiographic and medical records were related to self-report of fracture for 2,255 participants from the AGES Reykjavik Study. This data was used to determine false negative and false positive rates of self-reported fractures, correlates of misreporting, and the potential effect of the misreporting on estimates of health outcomes following fractures. Results In women, the false positive rate decreased with age as the false negative rate increased with no clear trend with age in men. Kappa values for agreement between FR and self-report were generally higher in women than men with the best agreement for forearm fracture (men 0.64 and women 0.82) and the least for rib (men 0.28 and women 0.25). Impaired cognition was a major factor associated with discordant answers between FR and self-report, OR 1.7 (95% CI: 1.3-2.1) (P < 0.0001). We estimated the effect of misreporting on health after fracture by comparison of the association of the self-report of fracture and fracture from the FR, adjusting for those factors associated with discordance. The weighted attenuation factor measured by mobility and muscle strength was 11% (95% CI: 0-24%) when adjusted for age and sex but reduced to 6% (95% CI: -10-22%) when adjusted for cognitive impairment. Conclusion Studies of hip fractures should include an independent ascertainment of fracture but for other fractures this study supports the use of self-report

Low-intensity pulsed ultrasound increases bone volume, osteoid thickness and mineral apposition rate in the area of fracture healing in patients with a delayed union of the osteotomized fibula

NARCIS (Netherlands)

Rutten, S.; Nolte, P.A.; Korstjens, C.M.; van Duin, M.A.; Klein-Nulend, J.